Initial Contribution

21 files changed, 36620 insertions, 0 deletions

diff --git a/distrib/libpng-1.2.19/Makefile b/distrib/libpng-1.2.19/Makefile
new file mode 100644
index 0000000..ba59f45
--- /dev/null
+++ b/distrib/libpng-1.2.19/Makefile
@@ -0,0 +1,25 @@
+# Makefile used to compile libpng statically
+# you need to define ZLIB_INCLUDE to the Zlib include path
+# and PREFIX to the installation path
+#
+LIBPNG_LIB    := $(SRC_PATH)/libpng.a
+LIBPNG_CFLAGS := -I$(LIBPNG_DIR)
+
+HOST_ARCH := $(shell uname -p)
+HOST_OS   := $(shell uname -s)
+ifeq ($(HOST_OS),Darwin)
+    HOST_OS := darwin
+endif
+
+include $(LIBPNG_DIR)/sources.make
+
+LIBPNG_OBJS := $(LIBPNG_SOURCES:%.c=%.o)
+
+$(LIBPNG_LIB): $(LIBPNG_OBJS)
+	ar ru $@ $(LIBPNG_OBJS)
+
+$(LIBPNG_OBJS): CFLAGS += $(ZLIB_CFLAGS) $(LIBPNG_CFLAGS)
+
+clean-libpng:
+	rm -f $(LIBPNG_OBJS) $(LIBPNG_LIB)
+
diff --git a/distrib/libpng-1.2.19/png.c b/distrib/libpng-1.2.19/png.c
new file mode 100644
index 0000000..8aa4131
--- /dev/null
+++ b/distrib/libpng-1.2.19/png.c
@@ -0,0 +1,895 @@
+
+/* png.c - location for general purpose libpng functions
+ *
+ * Last changed in libpng 1.2.19 August 18, 2007
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1998-2007 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ */
+
+#define PNG_INTERNAL
+#define PNG_NO_EXTERN
+#include "png.h"
+
+/* Generate a compiler error if there is an old png.h in the search path. */
+typedef version_1_2_19 Your_png_h_is_not_version_1_2_19;
+
+/* Version information for C files.  This had better match the version
+ * string defined in png.h.  */
+
+#ifdef PNG_USE_GLOBAL_ARRAYS
+/* png_libpng_ver was changed to a function in version 1.0.5c */
+PNG_CONST char png_libpng_ver[18] = PNG_LIBPNG_VER_STRING;
+
+#ifdef PNG_READ_SUPPORTED
+
+/* png_sig was changed to a function in version 1.0.5c */
+/* Place to hold the signature string for a PNG file. */
+PNG_CONST png_byte FARDATA png_sig[8] = {137, 80, 78, 71, 13, 10, 26, 10};
+#endif /* PNG_READ_SUPPORTED */
+
+/* Invoke global declarations for constant strings for known chunk types */
+PNG_IHDR;
+PNG_IDAT;
+PNG_IEND;
+PNG_PLTE;
+PNG_bKGD;
+PNG_cHRM;
+PNG_gAMA;
+PNG_hIST;
+PNG_iCCP;
+PNG_iTXt;
+PNG_oFFs;
+PNG_pCAL;
+PNG_sCAL;
+PNG_pHYs;
+PNG_sBIT;
+PNG_sPLT;
+PNG_sRGB;
+PNG_tEXt;
+PNG_tIME;
+PNG_tRNS;
+PNG_zTXt;
+
+#ifdef PNG_READ_SUPPORTED
+/* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+/* start of interlace block */
+PNG_CONST int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
+
+/* offset to next interlace block */
+PNG_CONST int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
+
+/* start of interlace block in the y direction */
+PNG_CONST int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
+
+/* offset to next interlace block in the y direction */
+PNG_CONST int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
+
+/* width of interlace block (used in assembler routines only) */
+#if defined(PNG_HAVE_MMX_COMBINE_ROW) || defined(PNG_OPTIMIZED_CODE_SUPPORTED)
+PNG_CONST int FARDATA png_pass_width[] = {8, 4, 4, 2, 2, 1, 1};
+#endif
+
+/* Height of interlace block.  This is not currently used - if you need
+ * it, uncomment it here and in png.h
+PNG_CONST int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
+*/
+
+/* Mask to determine which pixels are valid in a pass */
+PNG_CONST int FARDATA png_pass_mask[] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
+
+/* Mask to determine which pixels to overwrite while displaying */
+PNG_CONST int FARDATA png_pass_dsp_mask[]
+   = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
+
+#endif /* PNG_READ_SUPPORTED */
+#endif /* PNG_USE_GLOBAL_ARRAYS */
+
+/* Tells libpng that we have already handled the first "num_bytes" bytes
+ * of the PNG file signature.  If the PNG data is embedded into another
+ * stream we can set num_bytes = 8 so that libpng will not attempt to read
+ * or write any of the magic bytes before it starts on the IHDR.
+ */
+
+#ifdef PNG_READ_SUPPORTED
+void PNGAPI
+png_set_sig_bytes(png_structp png_ptr, int num_bytes)
+{
+   if(png_ptr == NULL) return;
+   png_debug(1, "in png_set_sig_bytes\n");
+   if (num_bytes > 8)
+      png_error(png_ptr, "Too many bytes for PNG signature.");
+
+   png_ptr->sig_bytes = (png_byte)(num_bytes < 0 ? 0 : num_bytes);
+}
+
+/* Checks whether the supplied bytes match the PNG signature.  We allow
+ * checking less than the full 8-byte signature so that those apps that
+ * already read the first few bytes of a file to determine the file type
+ * can simply check the remaining bytes for extra assurance.  Returns
+ * an integer less than, equal to, or greater than zero if sig is found,
+ * respectively, to be less than, to match, or be greater than the correct
+ * PNG signature (this is the same behaviour as strcmp, memcmp, etc).
+ */
+int PNGAPI
+png_sig_cmp(png_bytep sig, png_size_t start, png_size_t num_to_check)
+{
+   png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
+   if (num_to_check > 8)
+      num_to_check = 8;
+   else if (num_to_check < 1)
+      return (-1);
+
+   if (start > 7)
+      return (-1);
+
+   if (start + num_to_check > 8)
+      num_to_check = 8 - start;
+
+   return ((int)(png_memcmp(&sig[start], &png_signature[start], num_to_check)));
+}
+
+#if defined(PNG_1_0_X) || defined(PNG_1_2_X)
+/* (Obsolete) function to check signature bytes.  It does not allow one
+ * to check a partial signature.  This function might be removed in the
+ * future - use png_sig_cmp().  Returns true (nonzero) if the file is PNG.
+ */
+int PNGAPI
+png_check_sig(png_bytep sig, int num)
+{
+  return ((int)!png_sig_cmp(sig, (png_size_t)0, (png_size_t)num));
+}
+#endif
+#endif /* PNG_READ_SUPPORTED */
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+/* Function to allocate memory for zlib and clear it to 0. */
+#ifdef PNG_1_0_X
+voidpf PNGAPI
+#else
+voidpf /* private */
+#endif
+png_zalloc(voidpf png_ptr, uInt items, uInt size)
+{
+   png_voidp ptr;
+   png_structp p=(png_structp)png_ptr;
+   png_uint_32 save_flags=p->flags;
+   png_uint_32 num_bytes;
+
+   if(png_ptr == NULL) return (NULL);
+   if (items > PNG_UINT_32_MAX/size)
+   {
+     png_warning (p, "Potential overflow in png_zalloc()");
+     return (NULL);
+   }
+   num_bytes = (png_uint_32)items * size;
+
+   p->flags|=PNG_FLAG_MALLOC_NULL_MEM_OK;
+   ptr = (png_voidp)png_malloc((png_structp)png_ptr, num_bytes);
+   p->flags=save_flags;
+
+#if defined(PNG_1_0_X) && !defined(PNG_NO_ZALLOC_ZERO)
+   if (ptr == NULL)
+       return ((voidpf)ptr);
+
+   if (num_bytes > (png_uint_32)0x8000L)
+   {
+      png_memset(ptr, 0, (png_size_t)0x8000L);
+      png_memset((png_bytep)ptr + (png_size_t)0x8000L, 0,
+         (png_size_t)(num_bytes - (png_uint_32)0x8000L));
+   }
+   else
+   {
+      png_memset(ptr, 0, (png_size_t)num_bytes);
+   }
+#endif
+   return ((voidpf)ptr);
+}
+
+/* function to free memory for zlib */
+#ifdef PNG_1_0_X
+void PNGAPI
+#else
+void /* private */
+#endif
+png_zfree(voidpf png_ptr, voidpf ptr)
+{
+   png_free((png_structp)png_ptr, (png_voidp)ptr);
+}
+
+/* Reset the CRC variable to 32 bits of 1's.  Care must be taken
+ * in case CRC is > 32 bits to leave the top bits 0.
+ */
+void /* PRIVATE */
+png_reset_crc(png_structp png_ptr)
+{
+   png_ptr->crc = crc32(0, Z_NULL, 0);
+}
+
+/* Calculate the CRC over a section of data.  We can only pass as
+ * much data to this routine as the largest single buffer size.  We
+ * also check that this data will actually be used before going to the
+ * trouble of calculating it.
+ */
+void /* PRIVATE */
+png_calculate_crc(png_structp png_ptr, png_bytep ptr, png_size_t length)
+{
+   int need_crc = 1;
+
+   if (png_ptr->chunk_name[0] & 0x20)                     /* ancillary */
+   {
+      if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
+          (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
+         need_crc = 0;
+   }
+   else                                                    /* critical */
+   {
+      if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE)
+         need_crc = 0;
+   }
+
+   if (need_crc)
+      png_ptr->crc = crc32(png_ptr->crc, ptr, (uInt)length);
+}
+
+/* Allocate the memory for an info_struct for the application.  We don't
+ * really need the png_ptr, but it could potentially be useful in the
+ * future.  This should be used in favour of malloc(png_sizeof(png_info))
+ * and png_info_init() so that applications that want to use a shared
+ * libpng don't have to be recompiled if png_info changes size.
+ */
+png_infop PNGAPI
+png_create_info_struct(png_structp png_ptr)
+{
+   png_infop info_ptr;
+
+   png_debug(1, "in png_create_info_struct\n");
+   if(png_ptr == NULL) return (NULL);
+#ifdef PNG_USER_MEM_SUPPORTED
+   info_ptr = (png_infop)png_create_struct_2(PNG_STRUCT_INFO,
+      png_ptr->malloc_fn, png_ptr->mem_ptr);
+#else
+   info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);
+#endif
+   if (info_ptr != NULL)
+      png_info_init_3(&info_ptr, png_sizeof(png_info));
+
+   return (info_ptr);
+}
+
+/* This function frees the memory associated with a single info struct.
+ * Normally, one would use either png_destroy_read_struct() or
+ * png_destroy_write_struct() to free an info struct, but this may be
+ * useful for some applications.
+ */
+void PNGAPI
+png_destroy_info_struct(png_structp png_ptr, png_infopp info_ptr_ptr)
+{
+   png_infop info_ptr = NULL;
+   if(png_ptr == NULL) return;
+
+   png_debug(1, "in png_destroy_info_struct\n");
+   if (info_ptr_ptr != NULL)
+      info_ptr = *info_ptr_ptr;
+
+   if (info_ptr != NULL)
+   {
+      png_info_destroy(png_ptr, info_ptr);
+
+#ifdef PNG_USER_MEM_SUPPORTED
+      png_destroy_struct_2((png_voidp)info_ptr, png_ptr->free_fn,
+          png_ptr->mem_ptr);
+#else
+      png_destroy_struct((png_voidp)info_ptr);
+#endif
+      *info_ptr_ptr = NULL;
+   }
+}
+
+/* Initialize the info structure.  This is now an internal function (0.89)
+ * and applications using it are urged to use png_create_info_struct()
+ * instead.
+ */
+#if defined(PNG_1_0_X) || defined(PNG_1_2_X)
+#undef png_info_init
+void PNGAPI
+png_info_init(png_infop info_ptr)
+{
+   /* We only come here via pre-1.0.12-compiled applications */
+   png_info_init_3(&info_ptr, 0);
+}
+#endif
+
+void PNGAPI
+png_info_init_3(png_infopp ptr_ptr, png_size_t png_info_struct_size)
+{
+   png_infop info_ptr = *ptr_ptr;
+
+   if(info_ptr == NULL) return;
+
+   png_debug(1, "in png_info_init_3\n");
+
+   if(png_sizeof(png_info) > png_info_struct_size)
+     {
+       png_destroy_struct(info_ptr);
+       info_ptr = (png_infop)png_create_struct(PNG_STRUCT_INFO);
+       *ptr_ptr = info_ptr;
+     }
+
+   /* set everything to 0 */
+   png_memset(info_ptr, 0, png_sizeof (png_info));
+}
+
+#ifdef PNG_FREE_ME_SUPPORTED
+void PNGAPI
+png_data_freer(png_structp png_ptr, png_infop info_ptr,
+   int freer, png_uint_32 mask)
+{
+   png_debug(1, "in png_data_freer\n");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+   if(freer == PNG_DESTROY_WILL_FREE_DATA)
+      info_ptr->free_me |= mask;
+   else if(freer == PNG_USER_WILL_FREE_DATA)
+      info_ptr->free_me &= ~mask;
+   else
+      png_warning(png_ptr,
+         "Unknown freer parameter in png_data_freer.");
+}
+#endif
+
+void PNGAPI
+png_free_data(png_structp png_ptr, png_infop info_ptr, png_uint_32 mask,
+   int num)
+{
+   png_debug(1, "in png_free_data\n");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+#if defined(PNG_TEXT_SUPPORTED)
+/* free text item num or (if num == -1) all text items */
+#ifdef PNG_FREE_ME_SUPPORTED
+if ((mask & PNG_FREE_TEXT) & info_ptr->free_me)
+#else
+if (mask & PNG_FREE_TEXT)
+#endif
+{
+   if (num != -1)
+   {
+     if (info_ptr->text && info_ptr->text[num].key)
+     {
+         png_free(png_ptr, info_ptr->text[num].key);
+         info_ptr->text[num].key = NULL;
+     }
+   }
+   else
+   {
+       int i;
+       for (i = 0; i < info_ptr->num_text; i++)
+           png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, i);
+       png_free(png_ptr, info_ptr->text);
+       info_ptr->text = NULL;
+       info_ptr->num_text=0;
+   }
+}
+#endif
+
+#if defined(PNG_tRNS_SUPPORTED)
+/* free any tRNS entry */
+#ifdef PNG_FREE_ME_SUPPORTED
+if ((mask & PNG_FREE_TRNS) & info_ptr->free_me)
+#else
+if ((mask & PNG_FREE_TRNS) && (png_ptr->flags & PNG_FLAG_FREE_TRNS))
+#endif
+{
+    png_free(png_ptr, info_ptr->trans);
+    info_ptr->valid &= ~PNG_INFO_tRNS;
+#ifndef PNG_FREE_ME_SUPPORTED
+    png_ptr->flags &= ~PNG_FLAG_FREE_TRNS;
+#endif
+    info_ptr->trans = NULL;
+}
+#endif
+
+#if defined(PNG_sCAL_SUPPORTED)
+/* free any sCAL entry */
+#ifdef PNG_FREE_ME_SUPPORTED
+if ((mask & PNG_FREE_SCAL) & info_ptr->free_me)
+#else
+if (mask & PNG_FREE_SCAL)
+#endif
+{
+#if defined(PNG_FIXED_POINT_SUPPORTED) && !defined(PNG_FLOATING_POINT_SUPPORTED)
+    png_free(png_ptr, info_ptr->scal_s_width);
+    png_free(png_ptr, info_ptr->scal_s_height);
+    info_ptr->scal_s_width = NULL;
+    info_ptr->scal_s_height = NULL;
+#endif
+    info_ptr->valid &= ~PNG_INFO_sCAL;
+}
+#endif
+
+#if defined(PNG_pCAL_SUPPORTED)
+/* free any pCAL entry */
+#ifdef PNG_FREE_ME_SUPPORTED
+if ((mask & PNG_FREE_PCAL) & info_ptr->free_me)
+#else
+if (mask & PNG_FREE_PCAL)
+#endif
+{
+    png_free(png_ptr, info_ptr->pcal_purpose);
+    png_free(png_ptr, info_ptr->pcal_units);
+    info_ptr->pcal_purpose = NULL;
+    info_ptr->pcal_units = NULL;
+    if (info_ptr->pcal_params != NULL)
+    {
+        int i;
+        for (i = 0; i < (int)info_ptr->pcal_nparams; i++)
+        {
+          png_free(png_ptr, info_ptr->pcal_params[i]);
+          info_ptr->pcal_params[i]=NULL;
+        }
+        png_free(png_ptr, info_ptr->pcal_params);
+        info_ptr->pcal_params = NULL;
+    }
+    info_ptr->valid &= ~PNG_INFO_pCAL;
+}
+#endif
+
+#if defined(PNG_iCCP_SUPPORTED)
+/* free any iCCP entry */
+#ifdef PNG_FREE_ME_SUPPORTED
+if ((mask & PNG_FREE_ICCP) & info_ptr->free_me)
+#else
+if (mask & PNG_FREE_ICCP)
+#endif
+{
+    png_free(png_ptr, info_ptr->iccp_name);
+    png_free(png_ptr, info_ptr->iccp_profile);
+    info_ptr->iccp_name = NULL;
+    info_ptr->iccp_profile = NULL;
+    info_ptr->valid &= ~PNG_INFO_iCCP;
+}
+#endif
+
+#if defined(PNG_sPLT_SUPPORTED)
+/* free a given sPLT entry, or (if num == -1) all sPLT entries */
+#ifdef PNG_FREE_ME_SUPPORTED
+if ((mask & PNG_FREE_SPLT) & info_ptr->free_me)
+#else
+if (mask & PNG_FREE_SPLT)
+#endif
+{
+   if (num != -1)
+   {
+      if(info_ptr->splt_palettes)
+      {
+          png_free(png_ptr, info_ptr->splt_palettes[num].name);
+          png_free(png_ptr, info_ptr->splt_palettes[num].entries);
+          info_ptr->splt_palettes[num].name = NULL;
+          info_ptr->splt_palettes[num].entries = NULL;
+      }
+   }
+   else
+   {
+       if(info_ptr->splt_palettes_num)
+       {
+         int i;
+         for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
+            png_free_data(png_ptr, info_ptr, PNG_FREE_SPLT, i);
+
+         png_free(png_ptr, info_ptr->splt_palettes);
+         info_ptr->splt_palettes = NULL;
+         info_ptr->splt_palettes_num = 0;
+       }
+       info_ptr->valid &= ~PNG_INFO_sPLT;
+   }
+}
+#endif
+
+#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+  if(png_ptr->unknown_chunk.data)
+  {
+    png_free(png_ptr, png_ptr->unknown_chunk.data);
+    png_ptr->unknown_chunk.data = NULL;
+  }
+#ifdef PNG_FREE_ME_SUPPORTED
+if ((mask & PNG_FREE_UNKN) & info_ptr->free_me)
+#else
+if (mask & PNG_FREE_UNKN)
+#endif
+{
+   if (num != -1)
+   {
+       if(info_ptr->unknown_chunks)
+       {
+          png_free(png_ptr, info_ptr->unknown_chunks[num].data);
+          info_ptr->unknown_chunks[num].data = NULL;
+       }
+   }
+   else
+   {
+       int i;
+
+       if(info_ptr->unknown_chunks_num)
+       {
+         for (i = 0; i < (int)info_ptr->unknown_chunks_num; i++)
+            png_free_data(png_ptr, info_ptr, PNG_FREE_UNKN, i);
+
+         png_free(png_ptr, info_ptr->unknown_chunks);
+         info_ptr->unknown_chunks = NULL;
+         info_ptr->unknown_chunks_num = 0;
+       }
+   }
+}
+#endif
+
+#if defined(PNG_hIST_SUPPORTED)
+/* free any hIST entry */
+#ifdef PNG_FREE_ME_SUPPORTED
+if ((mask & PNG_FREE_HIST)  & info_ptr->free_me)
+#else
+if ((mask & PNG_FREE_HIST) && (png_ptr->flags & PNG_FLAG_FREE_HIST))
+#endif
+{
+    png_free(png_ptr, info_ptr->hist);
+    info_ptr->hist = NULL;
+    info_ptr->valid &= ~PNG_INFO_hIST;
+#ifndef PNG_FREE_ME_SUPPORTED
+    png_ptr->flags &= ~PNG_FLAG_FREE_HIST;
+#endif
+}
+#endif
+
+/* free any PLTE entry that was internally allocated */
+#ifdef PNG_FREE_ME_SUPPORTED
+if ((mask & PNG_FREE_PLTE) & info_ptr->free_me)
+#else
+if ((mask & PNG_FREE_PLTE) && (png_ptr->flags & PNG_FLAG_FREE_PLTE))
+#endif
+{
+    png_zfree(png_ptr, info_ptr->palette);
+    info_ptr->palette = NULL;
+    info_ptr->valid &= ~PNG_INFO_PLTE;
+#ifndef PNG_FREE_ME_SUPPORTED
+    png_ptr->flags &= ~PNG_FLAG_FREE_PLTE;
+#endif
+    info_ptr->num_palette = 0;
+}
+
+#if defined(PNG_INFO_IMAGE_SUPPORTED)
+/* free any image bits attached to the info structure */
+#ifdef PNG_FREE_ME_SUPPORTED
+if ((mask & PNG_FREE_ROWS) & info_ptr->free_me)
+#else
+if (mask & PNG_FREE_ROWS)
+#endif
+{
+    if(info_ptr->row_pointers)
+    {
+       int row;
+       for (row = 0; row < (int)info_ptr->height; row++)
+       {
+          png_free(png_ptr, info_ptr->row_pointers[row]);
+          info_ptr->row_pointers[row]=NULL;
+       }
+       png_free(png_ptr, info_ptr->row_pointers);
+       info_ptr->row_pointers=NULL;
+    }
+    info_ptr->valid &= ~PNG_INFO_IDAT;
+}
+#endif
+
+#ifdef PNG_FREE_ME_SUPPORTED
+   if(num == -1)
+     info_ptr->free_me &= ~mask;
+   else
+     info_ptr->free_me &= ~(mask & ~PNG_FREE_MUL);
+#endif
+}
+
+/* This is an internal routine to free any memory that the info struct is
+ * pointing to before re-using it or freeing the struct itself.  Recall
+ * that png_free() checks for NULL pointers for us.
+ */
+void /* PRIVATE */
+png_info_destroy(png_structp png_ptr, png_infop info_ptr)
+{
+   png_debug(1, "in png_info_destroy\n");
+
+   png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
+
+#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+   if (png_ptr->num_chunk_list)
+   {
+       png_free(png_ptr, png_ptr->chunk_list);
+       png_ptr->chunk_list=NULL;
+       png_ptr->num_chunk_list=0;
+   }
+#endif
+
+   png_info_init_3(&info_ptr, png_sizeof(png_info));
+}
+#endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
+
+/* This function returns a pointer to the io_ptr associated with the user
+ * functions.  The application should free any memory associated with this
+ * pointer before png_write_destroy() or png_read_destroy() are called.
+ */
+png_voidp PNGAPI
+png_get_io_ptr(png_structp png_ptr)
+{
+   if(png_ptr == NULL) return (NULL);
+   return (png_ptr->io_ptr);
+}
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+#if !defined(PNG_NO_STDIO)
+/* Initialize the default input/output functions for the PNG file.  If you
+ * use your own read or write routines, you can call either png_set_read_fn()
+ * or png_set_write_fn() instead of png_init_io().  If you have defined
+ * PNG_NO_STDIO, you must use a function of your own because "FILE *" isn't
+ * necessarily available.
+ */
+void PNGAPI
+png_init_io(png_structp png_ptr, png_FILE_p fp)
+{
+   png_debug(1, "in png_init_io\n");
+   if(png_ptr == NULL) return;
+   png_ptr->io_ptr = (png_voidp)fp;
+}
+#endif
+
+#if defined(PNG_TIME_RFC1123_SUPPORTED)
+/* Convert the supplied time into an RFC 1123 string suitable for use in
+ * a "Creation Time" or other text-based time string.
+ */
+png_charp PNGAPI
+png_convert_to_rfc1123(png_structp png_ptr, png_timep ptime)
+{
+   static PNG_CONST char short_months[12][4] =
+        {"Jan", "Feb", "Mar", "Apr", "May", "Jun",
+         "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"};
+
+   if(png_ptr == NULL) return (NULL);
+   if (png_ptr->time_buffer == NULL)
+   {
+      png_ptr->time_buffer = (png_charp)png_malloc(png_ptr, (png_uint_32)(29*
+         png_sizeof(char)));
+   }
+
+#if defined(_WIN32_WCE)
+   {
+      wchar_t time_buf[29];
+      wsprintf(time_buf, TEXT("%d %S %d %02d:%02d:%02d +0000"),
+          ptime->day % 32, short_months[(ptime->month - 1) % 12],
+        ptime->year, ptime->hour % 24, ptime->minute % 60,
+          ptime->second % 61);
+      WideCharToMultiByte(CP_ACP, 0, time_buf, -1, png_ptr->time_buffer, 29,
+          NULL, NULL);
+   }
+#else
+#ifdef USE_FAR_KEYWORD
+   {
+      char near_time_buf[29];
+      png_snprintf6(near_time_buf,29,"%d %s %d %02d:%02d:%02d +0000",
+          ptime->day % 32, short_months[(ptime->month - 1) % 12],
+          ptime->year, ptime->hour % 24, ptime->minute % 60,
+          ptime->second % 61);
+      png_memcpy(png_ptr->time_buffer, near_time_buf,
+          29*png_sizeof(char));
+   }
+#else
+   png_snprintf6(png_ptr->time_buffer,29,"%d %s %d %02d:%02d:%02d +0000",
+       ptime->day % 32, short_months[(ptime->month - 1) % 12],
+       ptime->year, ptime->hour % 24, ptime->minute % 60,
+       ptime->second % 61);
+#endif
+#endif /* _WIN32_WCE */
+   return ((png_charp)png_ptr->time_buffer);
+}
+#endif /* PNG_TIME_RFC1123_SUPPORTED */
+
+#endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
+
+png_charp PNGAPI
+png_get_copyright(png_structp png_ptr)
+{
+   png_ptr = png_ptr;  /* silence compiler warning about unused png_ptr */
+   return ((png_charp) "\n libpng version 1.2.19 - August 18, 2007\n\
+   Copyright (c) 1998-2007 Glenn Randers-Pehrson\n\
+   Copyright (c) 1996-1997 Andreas Dilger\n\
+   Copyright (c) 1995-1996 Guy Eric Schalnat, Group 42, Inc.\n");
+}
+
+/* The following return the library version as a short string in the
+ * format 1.0.0 through 99.99.99zz.  To get the version of *.h files
+ * used with your application, print out PNG_LIBPNG_VER_STRING, which
+ * is defined in png.h.
+ * Note: now there is no difference between png_get_libpng_ver() and
+ * png_get_header_ver().  Due to the version_nn_nn_nn typedef guard,
+ * it is guaranteed that png.c uses the correct version of png.h.
+ */
+png_charp PNGAPI
+png_get_libpng_ver(png_structp png_ptr)
+{
+   /* Version of *.c files used when building libpng */
+   png_ptr = png_ptr;  /* silence compiler warning about unused png_ptr */
+   return ((png_charp) PNG_LIBPNG_VER_STRING);
+}
+
+png_charp PNGAPI
+png_get_header_ver(png_structp png_ptr)
+{
+   /* Version of *.h files used when building libpng */
+   png_ptr = png_ptr;  /* silence compiler warning about unused png_ptr */
+   return ((png_charp) PNG_LIBPNG_VER_STRING);
+}
+
+png_charp PNGAPI
+png_get_header_version(png_structp png_ptr)
+{
+   /* Returns longer string containing both version and date */
+   png_ptr = png_ptr;  /* silence compiler warning about unused png_ptr */
+   return ((png_charp) PNG_HEADER_VERSION_STRING
+#ifdef PNG_READ_SUPPORTED
+#  ifdef PNG_USE_PNGGCCRD
+#    ifdef __x86_64__
+#      ifdef __PIC__
+   "     (PNGGCRD x86_64, PIC)\n"
+#      else
+#        ifdef PNG_THREAD_UNSAFE_OK
+   "     (PNGGCRD x86_64, Thread unsafe)\n"
+#        else
+   "     (PNGGCRD x86_64, Thread safe)\n"
+#        endif
+#      endif
+#    else
+#    ifdef PNG_THREAD_UNSAFE_OK
+   "     (PNGGCRD, Thread unsafe)\n"
+#      else
+   "     (PNGGCRD, Thread safe)\n"
+#      endif
+#    endif
+#  else
+#    ifdef PNG_USE_PNGVCRD
+#      ifdef __x86_64__
+   "     (x86_64 PNGVCRD)\n"
+#      else
+   "     (PNGVCRD)\n"
+#      endif
+#    else
+#      ifdef __x86_64__
+#        ifdef PNG_OPTIMIZED_CODE_SUPPORTED
+   "     (x86_64 OPTIMIZED)\n"
+#        else
+   "     (x86_64 NOT OPTIMIZED)\n"
+#        endif
+#      else
+#        ifdef PNG_OPTIMIZED_CODE_SUPPORTED
+   "     (OPTIMIZED)\n"
+#        else
+   "     (NOT OPTIMIZED)\n"
+#        endif
+#      endif
+#    endif
+#  endif
+#else
+   "     (NO READ SUPPORT)\n"
+#endif
+   );
+}
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+int PNGAPI
+png_handle_as_unknown(png_structp png_ptr, png_bytep chunk_name)
+{
+   /* check chunk_name and return "keep" value if it's on the list, else 0 */
+   int i;
+   png_bytep p;
+   if(png_ptr == NULL || chunk_name == NULL || png_ptr->num_chunk_list<=0)
+      return 0;
+   p=png_ptr->chunk_list+png_ptr->num_chunk_list*5-5;
+   for (i = png_ptr->num_chunk_list; i; i--, p-=5)
+      if (!png_memcmp(chunk_name, p, 4))
+        return ((int)*(p+4));
+   return 0;
+}
+#endif
+
+/* This function, added to libpng-1.0.6g, is untested. */
+int PNGAPI
+png_reset_zstream(png_structp png_ptr)
+{
+   if (png_ptr == NULL) return Z_STREAM_ERROR;
+   return (inflateReset(&png_ptr->zstream));
+}
+#endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
+
+/* This function was added to libpng-1.0.7 */
+png_uint_32 PNGAPI
+png_access_version_number(void)
+{
+   /* Version of *.c files used when building libpng */
+   return((png_uint_32) PNG_LIBPNG_VER);
+}
+
+
+#if defined(PNG_READ_SUPPORTED) && defined(PNG_ASSEMBLER_CODE_SUPPORTED)
+#if !defined(PNG_1_0_X)
+#if defined(PNG_MMX_CODE_SUPPORTED)
+/* this INTERNAL function was added to libpng 1.2.0 */
+void /* PRIVATE */
+png_init_mmx_flags (png_structp png_ptr)
+{
+    if(png_ptr == NULL) return;
+    png_ptr->mmx_rowbytes_threshold = 0;
+    png_ptr->mmx_bitdepth_threshold = 0;
+
+#  if (defined(PNG_USE_PNGVCRD) || defined(PNG_USE_PNGGCCRD))
+
+    png_ptr->asm_flags |= PNG_ASM_FLAG_MMX_SUPPORT_COMPILED;
+
+    if (png_mmx_support() > 0) {
+        png_ptr->asm_flags |= PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
+#    ifdef PNG_HAVE_MMX_COMBINE_ROW
+                              | PNG_ASM_FLAG_MMX_READ_COMBINE_ROW
+#    endif
+#    ifdef PNG_HAVE_MMX_READ_INTERLACE
+                              | PNG_ASM_FLAG_MMX_READ_INTERLACE
+#    endif
+#    ifndef PNG_HAVE_MMX_READ_FILTER_ROW
+                              ;
+#    else
+                              | PNG_ASM_FLAG_MMX_READ_FILTER_SUB
+                              | PNG_ASM_FLAG_MMX_READ_FILTER_UP
+                              | PNG_ASM_FLAG_MMX_READ_FILTER_AVG
+                              | PNG_ASM_FLAG_MMX_READ_FILTER_PAETH ;
+
+        png_ptr->mmx_rowbytes_threshold = PNG_MMX_ROWBYTES_THRESHOLD_DEFAULT;
+        png_ptr->mmx_bitdepth_threshold = PNG_MMX_BITDEPTH_THRESHOLD_DEFAULT;
+#    endif
+    } else {
+        png_ptr->asm_flags &= ~( PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU
+                               | PNG_MMX_READ_FLAGS
+                               | PNG_MMX_WRITE_FLAGS );
+    }
+
+#  else /* !(PNGVCRD || PNGGCCRD) */
+
+    /* clear all MMX flags; no support is compiled in */
+    png_ptr->asm_flags &= ~( PNG_MMX_FLAGS );
+
+#  endif /* ?(PNGVCRD || PNGGCCRD) */
+}
+
+#endif /* !(PNG_MMX_CODE_SUPPORTED) */
+
+/* this function was added to libpng 1.2.0 */
+#if !defined(PNG_USE_PNGGCCRD) && \
+    !(defined(PNG_MMX_CODE_SUPPORTED) && defined(PNG_USE_PNGVCRD))
+int PNGAPI
+png_mmx_support(void)
+{
+    return -1;
+}
+#endif
+#endif /* PNG_1_0_X */
+#endif /* PNG_READ_SUPPORTED && PNG_ASSEMBLER_CODE_SUPPORTED */
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+#ifdef PNG_SIZE_T
+/* Added at libpng version 1.2.6 */
+   PNG_EXTERN png_size_t PNGAPI png_convert_size PNGARG((size_t size));
+png_size_t PNGAPI
+png_convert_size(size_t size)
+{
+  if (size > (png_size_t)-1)
+     PNG_ABORT();  /* We haven't got access to png_ptr, so no png_error() */
+  return ((png_size_t)size);
+}
+#endif /* PNG_SIZE_T */
+#endif /* defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED) */
diff --git a/distrib/libpng-1.2.19/png.h b/distrib/libpng-1.2.19/png.h
new file mode 100644
index 0000000..04f786d
--- /dev/null
+++ b/distrib/libpng-1.2.19/png.h
@@ -0,0 +1,3525 @@
+
+/* png.h - header file for PNG reference library
+ *
+ * libpng version 1.2.19 - August 18, 2007
+ * Copyright (c) 1998-2007 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * Authors and maintainers:
+ *  libpng versions 0.71, May 1995, through 0.88, January 1996: Guy Schalnat
+ *  libpng versions 0.89c, June 1996, through 0.96, May 1997: Andreas Dilger
+ *  libpng versions 0.97, January 1998, through 1.2.19 - August 18, 2007: Glenn
+ *  See also "Contributing Authors", below.
+ *
+ * Note about libpng version numbers:
+ *
+ *    Due to various miscommunications, unforeseen code incompatibilities
+ *    and occasional factors outside the authors' control, version numbering
+ *    on the library has not always been consistent and straightforward.
+ *    The following table summarizes matters since version 0.89c, which was
+ *    the first widely used release:
+ *
+ *    source                 png.h  png.h  shared-lib
+ *    version                string   int  version
+ *    -------                ------ -----  ----------
+ *    0.89c "1.0 beta 3"     0.89      89  1.0.89
+ *    0.90  "1.0 beta 4"     0.90      90  0.90  [should have been 2.0.90]
+ *    0.95  "1.0 beta 5"     0.95      95  0.95  [should have been 2.0.95]
+ *    0.96  "1.0 beta 6"     0.96      96  0.96  [should have been 2.0.96]
+ *    0.97b "1.00.97 beta 7" 1.00.97   97  1.0.1 [should have been 2.0.97]
+ *    0.97c                  0.97      97  2.0.97
+ *    0.98                   0.98      98  2.0.98
+ *    0.99                   0.99      98  2.0.99
+ *    0.99a-m                0.99      99  2.0.99
+ *    1.00                   1.00     100  2.1.0 [100 should be 10000]
+ *    1.0.0      (from here on, the   100  2.1.0 [100 should be 10000]
+ *    1.0.1       png.h string is   10001  2.1.0
+ *    1.0.1a-e    identical to the  10002  from here on, the shared library
+ *    1.0.2       source version)   10002  is 2.V where V is the source code
+ *    1.0.2a-b                      10003  version, except as noted.
+ *    1.0.3                         10003
+ *    1.0.3a-d                      10004
+ *    1.0.4                         10004
+ *    1.0.4a-f                      10005
+ *    1.0.5 (+ 2 patches)           10005
+ *    1.0.5a-d                      10006
+ *    1.0.5e-r                      10100 (not source compatible)
+ *    1.0.5s-v                      10006 (not binary compatible)
+ *    1.0.6 (+ 3 patches)           10006 (still binary incompatible)
+ *    1.0.6d-f                      10007 (still binary incompatible)
+ *    1.0.6g                        10007
+ *    1.0.6h                        10007  10.6h (testing xy.z so-numbering)
+ *    1.0.6i                        10007  10.6i
+ *    1.0.6j                        10007  2.1.0.6j (incompatible with 1.0.0)
+ *    1.0.7beta11-14        DLLNUM  10007  2.1.0.7beta11-14 (binary compatible)
+ *    1.0.7beta15-18           1    10007  2.1.0.7beta15-18 (binary compatible)
+ *    1.0.7rc1-2               1    10007  2.1.0.7rc1-2 (binary compatible)
+ *    1.0.7                    1    10007  (still compatible)
+ *    1.0.8beta1-4             1    10008  2.1.0.8beta1-4
+ *    1.0.8rc1                 1    10008  2.1.0.8rc1
+ *    1.0.8                    1    10008  2.1.0.8
+ *    1.0.9beta1-6             1    10009  2.1.0.9beta1-6
+ *    1.0.9rc1                 1    10009  2.1.0.9rc1
+ *    1.0.9beta7-10            1    10009  2.1.0.9beta7-10
+ *    1.0.9rc2                 1    10009  2.1.0.9rc2
+ *    1.0.9                    1    10009  2.1.0.9
+ *    1.0.10beta1              1    10010  2.1.0.10beta1
+ *    1.0.10rc1                1    10010  2.1.0.10rc1
+ *    1.0.10                   1    10010  2.1.0.10
+ *    1.0.11beta1-3            1    10011  2.1.0.11beta1-3
+ *    1.0.11rc1                1    10011  2.1.0.11rc1
+ *    1.0.11                   1    10011  2.1.0.11
+ *    1.0.12beta1-2            2    10012  2.1.0.12beta1-2
+ *    1.0.12rc1                2    10012  2.1.0.12rc1
+ *    1.0.12                   2    10012  2.1.0.12
+ *    1.1.0a-f                 -    10100  2.1.1.0a-f (branch abandoned)
+ *    1.2.0beta1-2             2    10200  2.1.2.0beta1-2
+ *    1.2.0beta3-5             3    10200  3.1.2.0beta3-5
+ *    1.2.0rc1                 3    10200  3.1.2.0rc1
+ *    1.2.0                    3    10200  3.1.2.0
+ *    1.2.1beta1-4             3    10201  3.1.2.1beta1-4
+ *    1.2.1rc1-2               3    10201  3.1.2.1rc1-2
+ *    1.2.1                    3    10201  3.1.2.1
+ *    1.2.2beta1-6            12    10202  12.so.0.1.2.2beta1-6
+ *    1.0.13beta1             10    10013  10.so.0.1.0.13beta1
+ *    1.0.13rc1               10    10013  10.so.0.1.0.13rc1
+ *    1.2.2rc1                12    10202  12.so.0.1.2.2rc1
+ *    1.0.13                  10    10013  10.so.0.1.0.13
+ *    1.2.2                   12    10202  12.so.0.1.2.2
+ *    1.2.3rc1-6              12    10203  12.so.0.1.2.3rc1-6
+ *    1.2.3                   12    10203  12.so.0.1.2.3
+ *    1.2.4beta1-3            13    10204  12.so.0.1.2.4beta1-3
+ *    1.0.14rc1               13    10014  10.so.0.1.0.14rc1
+ *    1.2.4rc1                13    10204  12.so.0.1.2.4rc1
+ *    1.0.14                  10    10014  10.so.0.1.0.14
+ *    1.2.4                   13    10204  12.so.0.1.2.4
+ *    1.2.5beta1-2            13    10205  12.so.0.1.2.5beta1-2
+ *    1.0.15rc1-3             10    10015  10.so.0.1.0.15rc1-3
+ *    1.2.5rc1-3              13    10205  12.so.0.1.2.5rc1-3
+ *    1.0.15                  10    10015  10.so.0.1.0.15
+ *    1.2.5                   13    10205  12.so.0.1.2.5
+ *    1.2.6beta1-4            13    10206  12.so.0.1.2.6beta1-4
+ *    1.0.16                  10    10016  10.so.0.1.0.16
+ *    1.2.6                   13    10206  12.so.0.1.2.6
+ *    1.2.7beta1-2            13    10207  12.so.0.1.2.7beta1-2
+ *    1.0.17rc1               10    10017  10.so.0.1.0.17rc1
+ *    1.2.7rc1                13    10207  12.so.0.1.2.7rc1
+ *    1.0.17                  10    10017  10.so.0.1.0.17
+ *    1.2.7                   13    10207  12.so.0.1.2.7
+ *    1.2.8beta1-5            13    10208  12.so.0.1.2.8beta1-5
+ *    1.0.18rc1-5             10    10018  10.so.0.1.0.18rc1-5
+ *    1.2.8rc1-5              13    10208  12.so.0.1.2.8rc1-5
+ *    1.0.18                  10    10018  10.so.0.1.0.18
+ *    1.2.8                   13    10208  12.so.0.1.2.8
+ *    1.2.9beta1-3            13    10209  12.so.0.1.2.9beta1-3
+ *    1.2.9beta4-11           13    10209  12.so.0.9[.0]
+ *    1.2.9rc1                13    10209  12.so.0.9[.0]
+ *    1.2.9                   13    10209  12.so.0.9[.0]
+ *    1.2.10beta1-8           13    10210  12.so.0.10[.0]
+ *    1.2.10rc1-3             13    10210  12.so.0.10[.0]
+ *    1.2.10                  13    10210  12.so.0.10[.0]
+ *    1.2.11beta1-4           13    10211  12.so.0.11[.0]
+ *    1.0.19rc1-5             10    10019  10.so.0.19[.0]
+ *    1.2.11rc1-5             13    10211  12.so.0.11[.0]
+ *    1.0.19                  10    10019  10.so.0.19[.0]
+ *    1.2.11                  13    10211  12.so.0.11[.0]
+ *    1.0.20                  10    10020  10.so.0.20[.0]
+ *    1.2.12                  13    10212  12.so.0.12[.0]
+ *    1.2.13beta1             13    10213  12.so.0.13[.0]
+ *    1.0.21                  10    10021  10.so.0.21[.0]
+ *    1.2.13                  13    10213  12.so.0.13[.0]
+ *    1.2.14beta1-2           13    10214  12.so.0.14[.0]
+ *    1.0.22rc1               10    10022  10.so.0.22[.0]
+ *    1.2.14rc1               13    10214  12.so.0.14[.0]
+ *    1.0.22                  10    10022  10.so.0.22[.0]
+ *    1.2.14                  13    10214  12.so.0.14[.0]
+ *    1.2.15beta1-6           13    10215  12.so.0.15[.0]
+ *    1.0.23rc1-5             10    10023  10.so.0.23[.0]
+ *    1.2.15rc1-5             13    10215  12.so.0.15[.0]
+ *    1.0.23                  10    10023  10.so.0.23[.0]
+ *    1.2.15                  13    10215  12.so.0.15[.0]
+ *    1.2.16beta1-2           13    10216  12.so.0.16[.0]
+ *    1.2.16rc1               13    10216  12.so.0.16[.0]
+ *    1.0.24                  10    10024  10.so.0.24[.0]
+ *    1.2.16                  13    10216  12.so.0.16[.0]
+ *    1.2.17beta1-2           13    10217  12.so.0.17[.0]
+ *    1.0.25rc1               10    10025  10.so.0.25[.0]
+ *    1.2.17rc1-3             13    10217  12.so.0.17[.0]
+ *    1.0.25                  10    10025  10.so.0.25[.0]
+ *    1.2.17                  13    10217  12.so.0.17[.0]
+ *    1.0.26                  10    10026  10.so.0.26[.0]
+ *    1.2.18                  13    10218  12.so.0.18[.0]
+ *    1.2.19beta1-31          13    10219  12.so.0.19[.0]
+ *    1.0.27rc1-6             10    10027  10.so.0.27[.0]
+ *    1.2.19rc1-6             13    10219  12.so.0.19[.0]
+ *    1.0.27                  10    10027  10.so.0.27[.0]
+ *    1.2.19                  13    10219  12.so.0.19[.0]
+ *
+ *    Henceforth the source version will match the shared-library major
+ *    and minor numbers; the shared-library major version number will be
+ *    used for changes in backward compatibility, as it is intended.  The
+ *    PNG_LIBPNG_VER macro, which is not used within libpng but is available
+ *    for applications, is an unsigned integer of the form xyyzz corresponding
+ *    to the source version x.y.z (leading zeros in y and z).  Beta versions
+ *    were given the previous public release number plus a letter, until
+ *    version 1.0.6j; from then on they were given the upcoming public
+ *    release number plus "betaNN" or "rcN".
+ *
+ *    Binary incompatibility exists only when applications make direct access
+ *    to the info_ptr or png_ptr members through png.h, and the compiled
+ *    application is loaded with a different version of the library.
+ *
+ *    DLLNUM will change each time there are forward or backward changes
+ *    in binary compatibility (e.g., when a new feature is added).
+ *
+ * See libpng.txt or libpng.3 for more information.  The PNG specification
+ * is available as a W3C Recommendation and as an ISO Specification,
+ * <http://www.w3.org/TR/2003/REC-PNG-20031110/
+ */
+
+/*
+ * COPYRIGHT NOTICE, DISCLAIMER, and LICENSE:
+ *
+ * If you modify libpng you may insert additional notices immediately following
+ * this sentence.
+ *
+ * libpng versions 1.2.6, August 15, 2004, through 1.2.19, August 18, 2007, are
+ * Copyright (c) 2004, 2006-2007 Glenn Randers-Pehrson, and are
+ * distributed according to the same disclaimer and license as libpng-1.2.5
+ * with the following individual added to the list of Contributing Authors:
+ *
+ *    Cosmin Truta
+ *
+ * libpng versions 1.0.7, July 1, 2000, through 1.2.5, October 3, 2002, are
+ * Copyright (c) 2000-2002 Glenn Randers-Pehrson, and are
+ * distributed according to the same disclaimer and license as libpng-1.0.6
+ * with the following individuals added to the list of Contributing Authors:
+ *
+ *    Simon-Pierre Cadieux
+ *    Eric S. Raymond
+ *    Gilles Vollant
+ *
+ * and with the following additions to the disclaimer:
+ *
+ *    There is no warranty against interference with your enjoyment of the
+ *    library or against infringement.  There is no warranty that our
+ *    efforts or the library will fulfill any of your particular purposes
+ *    or needs.  This library is provided with all faults, and the entire
+ *    risk of satisfactory quality, performance, accuracy, and effort is with
+ *    the user.
+ *
+ * libpng versions 0.97, January 1998, through 1.0.6, March 20, 2000, are
+ * Copyright (c) 1998, 1999, 2000 Glenn Randers-Pehrson, and are
+ * distributed according to the same disclaimer and license as libpng-0.96,
+ * with the following individuals added to the list of Contributing Authors:
+ *
+ *    Tom Lane
+ *    Glenn Randers-Pehrson
+ *    Willem van Schaik
+ *
+ * libpng versions 0.89, June 1996, through 0.96, May 1997, are
+ * Copyright (c) 1996, 1997 Andreas Dilger
+ * Distributed according to the same disclaimer and license as libpng-0.88,
+ * with the following individuals added to the list of Contributing Authors:
+ *
+ *    John Bowler
+ *    Kevin Bracey
+ *    Sam Bushell
+ *    Magnus Holmgren
+ *    Greg Roelofs
+ *    Tom Tanner
+ *
+ * libpng versions 0.5, May 1995, through 0.88, January 1996, are
+ * Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.
+ *
+ * For the purposes of this copyright and license, "Contributing Authors"
+ * is defined as the following set of individuals:
+ *
+ *    Andreas Dilger
+ *    Dave Martindale
+ *    Guy Eric Schalnat
+ *    Paul Schmidt
+ *    Tim Wegner
+ *
+ * The PNG Reference Library is supplied "AS IS".  The Contributing Authors
+ * and Group 42, Inc. disclaim all warranties, expressed or implied,
+ * including, without limitation, the warranties of merchantability and of
+ * fitness for any purpose.  The Contributing Authors and Group 42, Inc.
+ * assume no liability for direct, indirect, incidental, special, exemplary,
+ * or consequential damages, which may result from the use of the PNG
+ * Reference Library, even if advised of the possibility of such damage.
+ *
+ * Permission is hereby granted to use, copy, modify, and distribute this
+ * source code, or portions hereof, for any purpose, without fee, subject
+ * to the following restrictions:
+ *
+ * 1. The origin of this source code must not be misrepresented.
+ *
+ * 2. Altered versions must be plainly marked as such and
+ * must not be misrepresented as being the original source.
+ *
+ * 3. This Copyright notice may not be removed or altered from
+ *    any source or altered source distribution.
+ *
+ * The Contributing Authors and Group 42, Inc. specifically permit, without
+ * fee, and encourage the use of this source code as a component to
+ * supporting the PNG file format in commercial products.  If you use this
+ * source code in a product, acknowledgment is not required but would be
+ * appreciated.
+ */
+
+/*
+ * A "png_get_copyright" function is available, for convenient use in "about"
+ * boxes and the like:
+ *
+ * printf("%s",png_get_copyright(NULL));
+ *
+ * Also, the PNG logo (in PNG format, of course) is supplied in the
+ * files "pngbar.png" and "pngbar.jpg (88x31) and "pngnow.png" (98x31).
+ */
+
+/*
+ * Libpng is OSI Certified Open Source Software.  OSI Certified is a
+ * certification mark of the Open Source Initiative.
+ */
+
+/*
+ * The contributing authors would like to thank all those who helped
+ * with testing, bug fixes, and patience.  This wouldn't have been
+ * possible without all of you.
+ *
+ * Thanks to Frank J. T. Wojcik for helping with the documentation.
+ */
+
+/*
+ * Y2K compliance in libpng:
+ * =========================
+ *
+ *    August 18, 2007
+ *
+ *    Since the PNG Development group is an ad-hoc body, we can't make
+ *    an official declaration.
+ *
+ *    This is your unofficial assurance that libpng from version 0.71 and
+ *    upward through 1.2.19 are Y2K compliant.  It is my belief that earlier
+ *    versions were also Y2K compliant.
+ *
+ *    Libpng only has three year fields.  One is a 2-byte unsigned integer
+ *    that will hold years up to 65535.  The other two hold the date in text
+ *    format, and will hold years up to 9999.
+ *
+ *    The integer is
+ *        "png_uint_16 year" in png_time_struct.
+ *
+ *    The strings are
+ *        "png_charp time_buffer" in png_struct and
+ *        "near_time_buffer", which is a local character string in png.c.
+ *
+ *    There are seven time-related functions:
+ *        png.c: png_convert_to_rfc_1123() in png.c
+ *          (formerly png_convert_to_rfc_1152() in error)
+ *        png_convert_from_struct_tm() in pngwrite.c, called in pngwrite.c
+ *        png_convert_from_time_t() in pngwrite.c
+ *        png_get_tIME() in pngget.c
+ *        png_handle_tIME() in pngrutil.c, called in pngread.c
+ *        png_set_tIME() in pngset.c
+ *        png_write_tIME() in pngwutil.c, called in pngwrite.c
+ *
+ *    All handle dates properly in a Y2K environment.  The
+ *    png_convert_from_time_t() function calls gmtime() to convert from system
+ *    clock time, which returns (year - 1900), which we properly convert to
+ *    the full 4-digit year.  There is a possibility that applications using
+ *    libpng are not passing 4-digit years into the png_convert_to_rfc_1123()
+ *    function, or that they are incorrectly passing only a 2-digit year
+ *    instead of "year - 1900" into the png_convert_from_struct_tm() function,
+ *    but this is not under our control.  The libpng documentation has always
+ *    stated that it works with 4-digit years, and the APIs have been
+ *    documented as such.
+ *
+ *    The tIME chunk itself is also Y2K compliant.  It uses a 2-byte unsigned
+ *    integer to hold the year, and can hold years as large as 65535.
+ *
+ *    zlib, upon which libpng depends, is also Y2K compliant.  It contains
+ *    no date-related code.
+ *
+ *       Glenn Randers-Pehrson
+ *       libpng maintainer
+ *       PNG Development Group
+ */
+
+#ifndef PNG_H
+#define PNG_H
+
+/* This is not the place to learn how to use libpng.  The file libpng.txt
+ * describes how to use libpng, and the file example.c summarizes it
+ * with some code on which to build.  This file is useful for looking
+ * at the actual function definitions and structure components.
+ */
+
+/* Version information for png.h - this should match the version in png.c */
+#define PNG_LIBPNG_VER_STRING "1.2.19"
+#define PNG_HEADER_VERSION_STRING \
+   " libpng version 1.2.19 - August 18, 2007\n"
+
+#define PNG_LIBPNG_VER_SONUM   0
+#define PNG_LIBPNG_VER_DLLNUM  13
+
+/* These should match the first 3 components of PNG_LIBPNG_VER_STRING: */
+#define PNG_LIBPNG_VER_MAJOR   1
+#define PNG_LIBPNG_VER_MINOR   2
+#define PNG_LIBPNG_VER_RELEASE 19
+/* This should match the numeric part of the final component of
+ * PNG_LIBPNG_VER_STRING, omitting any leading zero: */
+
+#define PNG_LIBPNG_VER_BUILD  0
+
+/* Release Status */
+#define PNG_LIBPNG_BUILD_ALPHA    1
+#define PNG_LIBPNG_BUILD_BETA     2
+#define PNG_LIBPNG_BUILD_RC       3
+#define PNG_LIBPNG_BUILD_STABLE   4
+#define PNG_LIBPNG_BUILD_RELEASE_STATUS_MASK 7
+  
+/* Release-Specific Flags */
+#define PNG_LIBPNG_BUILD_PATCH    8 /* Can be OR'ed with
+                                       PNG_LIBPNG_BUILD_STABLE only */
+#define PNG_LIBPNG_BUILD_PRIVATE 16 /* Cannot be OR'ed with
+                                       PNG_LIBPNG_BUILD_SPECIAL */
+#define PNG_LIBPNG_BUILD_SPECIAL 32 /* Cannot be OR'ed with
+                                       PNG_LIBPNG_BUILD_PRIVATE */
+
+#define PNG_LIBPNG_BUILD_BASE_TYPE PNG_LIBPNG_BUILD_STABLE
+
+/* Careful here.  At one time, Guy wanted to use 082, but that would be octal.
+ * We must not include leading zeros.
+ * Versions 0.7 through 1.0.0 were in the range 0 to 100 here (only
+ * version 1.0.0 was mis-numbered 100 instead of 10000).  From
+ * version 1.0.1 it's    xxyyzz, where x=major, y=minor, z=release */
+#define PNG_LIBPNG_VER 10219 /* 1.2.19 */
+
+#ifndef PNG_VERSION_INFO_ONLY
+/* include the compression library's header */
+#include "zlib.h"
+#endif
+
+/* include all user configurable info, including optional assembler routines */
+#include "pngconf.h"
+
+/*
+ * Added at libpng-1.2.8 */
+/* Ref MSDN: Private as priority over Special
+ * VS_FF_PRIVATEBUILD File *was not* built using standard release
+ * procedures. If this value is given, the StringFileInfo block must
+ * contain a PrivateBuild string. 
+ *
+ * VS_FF_SPECIALBUILD File *was* built by the original company using
+ * standard release procedures but is a variation of the standard
+ * file of the same version number. If this value is given, the
+ * StringFileInfo block must contain a SpecialBuild string. 
+ */
+
+#if defined(PNG_USER_PRIVATEBUILD)
+#  define PNG_LIBPNG_BUILD_TYPE \
+          (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_PRIVATE)
+#else
+#  if defined(PNG_LIBPNG_SPECIALBUILD)
+#    define PNG_LIBPNG_BUILD_TYPE \
+            (PNG_LIBPNG_BUILD_BASE_TYPE | PNG_LIBPNG_BUILD_SPECIAL)
+#  else
+#    define PNG_LIBPNG_BUILD_TYPE (PNG_LIBPNG_BUILD_BASE_TYPE)
+#  endif
+#endif
+
+#ifndef PNG_VERSION_INFO_ONLY
+
+/* Inhibit C++ name-mangling for libpng functions but not for system calls. */
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+
+/* This file is arranged in several sections.  The first section contains
+ * structure and type definitions.  The second section contains the external
+ * library functions, while the third has the internal library functions,
+ * which applications aren't expected to use directly.
+ */
+
+#ifndef PNG_NO_TYPECAST_NULL
+#define int_p_NULL                (int *)NULL
+#define png_bytep_NULL            (png_bytep)NULL
+#define png_bytepp_NULL           (png_bytepp)NULL
+#define png_doublep_NULL          (png_doublep)NULL
+#define png_error_ptr_NULL        (png_error_ptr)NULL
+#define png_flush_ptr_NULL        (png_flush_ptr)NULL
+#define png_free_ptr_NULL         (png_free_ptr)NULL
+#define png_infopp_NULL           (png_infopp)NULL
+#define png_malloc_ptr_NULL       (png_malloc_ptr)NULL
+#define png_read_status_ptr_NULL  (png_read_status_ptr)NULL
+#define png_rw_ptr_NULL           (png_rw_ptr)NULL
+#define png_structp_NULL          (png_structp)NULL
+#define png_uint_16p_NULL         (png_uint_16p)NULL
+#define png_voidp_NULL            (png_voidp)NULL
+#define png_write_status_ptr_NULL (png_write_status_ptr)NULL
+#else
+#define int_p_NULL                NULL
+#define png_bytep_NULL            NULL
+#define png_bytepp_NULL           NULL
+#define png_doublep_NULL          NULL
+#define png_error_ptr_NULL        NULL
+#define png_flush_ptr_NULL        NULL
+#define png_free_ptr_NULL         NULL
+#define png_infopp_NULL           NULL
+#define png_malloc_ptr_NULL       NULL
+#define png_read_status_ptr_NULL  NULL
+#define png_rw_ptr_NULL           NULL
+#define png_structp_NULL          NULL
+#define png_uint_16p_NULL         NULL
+#define png_voidp_NULL            NULL
+#define png_write_status_ptr_NULL NULL
+#endif
+
+/* variables declared in png.c - only it needs to define PNG_NO_EXTERN */
+#if !defined(PNG_NO_EXTERN) || defined(PNG_ALWAYS_EXTERN)
+/* Version information for C files, stored in png.c.  This had better match
+ * the version above.
+ */
+#ifdef PNG_USE_GLOBAL_ARRAYS
+PNG_EXPORT_VAR (PNG_CONST char) png_libpng_ver[18];
+  /* need room for 99.99.99beta99z */
+#else
+#define png_libpng_ver png_get_header_ver(NULL)
+#endif
+
+#ifdef PNG_USE_GLOBAL_ARRAYS
+/* This was removed in version 1.0.5c */
+/* Structures to facilitate easy interlacing.  See png.c for more details */
+PNG_EXPORT_VAR (PNG_CONST int FARDATA) png_pass_start[7];
+PNG_EXPORT_VAR (PNG_CONST int FARDATA) png_pass_inc[7];
+PNG_EXPORT_VAR (PNG_CONST int FARDATA) png_pass_ystart[7];
+PNG_EXPORT_VAR (PNG_CONST int FARDATA) png_pass_yinc[7];
+PNG_EXPORT_VAR (PNG_CONST int FARDATA) png_pass_mask[7];
+PNG_EXPORT_VAR (PNG_CONST int FARDATA) png_pass_dsp_mask[7];
+#if defined(PNG_HAVE_MMX_COMBINE_ROW) || defined(PNG_OPTIMIZED_CODE_SUPPORTED)
+PNG_EXPORT_VAR (PNG_CONST int FARDATA) png_pass_width[7];
+#endif
+/* This isn't currently used.  If you need it, see png.c for more details.
+PNG_EXPORT_VAR (PNG_CONST int FARDATA) png_pass_height[7];
+*/
+#endif
+
+#endif /* PNG_NO_EXTERN */
+
+/* Three color definitions.  The order of the red, green, and blue, (and the
+ * exact size) is not important, although the size of the fields need to
+ * be png_byte or png_uint_16 (as defined below).
+ */
+typedef struct png_color_struct
+{
+   png_byte red;
+   png_byte green;
+   png_byte blue;
+} png_color;
+typedef png_color FAR * png_colorp;
+typedef png_color FAR * FAR * png_colorpp;
+
+typedef struct png_color_16_struct
+{
+   png_byte index;    /* used for palette files */
+   png_uint_16 red;   /* for use in red green blue files */
+   png_uint_16 green;
+   png_uint_16 blue;
+   png_uint_16 gray;  /* for use in grayscale files */
+} png_color_16;
+typedef png_color_16 FAR * png_color_16p;
+typedef png_color_16 FAR * FAR * png_color_16pp;
+
+typedef struct png_color_8_struct
+{
+   png_byte red;   /* for use in red green blue files */
+   png_byte green;
+   png_byte blue;
+   png_byte gray;  /* for use in grayscale files */
+   png_byte alpha; /* for alpha channel files */
+} png_color_8;
+typedef png_color_8 FAR * png_color_8p;
+typedef png_color_8 FAR * FAR * png_color_8pp;
+
+/*
+ * The following two structures are used for the in-core representation
+ * of sPLT chunks.
+ */
+typedef struct png_sPLT_entry_struct
+{
+   png_uint_16 red;
+   png_uint_16 green;
+   png_uint_16 blue;
+   png_uint_16 alpha;
+   png_uint_16 frequency;
+} png_sPLT_entry;
+typedef png_sPLT_entry FAR * png_sPLT_entryp;
+typedef png_sPLT_entry FAR * FAR * png_sPLT_entrypp;
+
+/*  When the depth of the sPLT palette is 8 bits, the color and alpha samples
+ *  occupy the LSB of their respective members, and the MSB of each member
+ *  is zero-filled.  The frequency member always occupies the full 16 bits.
+ */
+
+typedef struct png_sPLT_struct
+{
+   png_charp name;           /* palette name */
+   png_byte depth;           /* depth of palette samples */
+   png_sPLT_entryp entries;  /* palette entries */
+   png_int_32 nentries;      /* number of palette entries */
+} png_sPLT_t;
+typedef png_sPLT_t FAR * png_sPLT_tp;
+typedef png_sPLT_t FAR * FAR * png_sPLT_tpp;
+
+#ifdef PNG_TEXT_SUPPORTED
+/* png_text holds the contents of a text/ztxt/itxt chunk in a PNG file,
+ * and whether that contents is compressed or not.  The "key" field
+ * points to a regular zero-terminated C string.  The "text", "lang", and
+ * "lang_key" fields can be regular C strings, empty strings, or NULL pointers.
+ * However, the * structure returned by png_get_text() will always contain
+ * regular zero-terminated C strings (possibly empty), never NULL pointers,
+ * so they can be safely used in printf() and other string-handling functions.
+ */
+typedef struct png_text_struct
+{
+   int  compression;       /* compression value:
+                             -1: tEXt, none
+                              0: zTXt, deflate
+                              1: iTXt, none
+                              2: iTXt, deflate  */
+   png_charp key;          /* keyword, 1-79 character description of "text" */
+   png_charp text;         /* comment, may be an empty string (ie "")
+                              or a NULL pointer */
+   png_size_t text_length; /* length of the text string */
+#ifdef PNG_iTXt_SUPPORTED
+   png_size_t itxt_length; /* length of the itxt string */
+   png_charp lang;         /* language code, 0-79 characters
+                              or a NULL pointer */
+   png_charp lang_key;     /* keyword translated UTF-8 string, 0 or more
+                              chars or a NULL pointer */
+#endif
+} png_text;
+typedef png_text FAR * png_textp;
+typedef png_text FAR * FAR * png_textpp;
+#endif
+
+/* Supported compression types for text in PNG files (tEXt, and zTXt).
+ * The values of the PNG_TEXT_COMPRESSION_ defines should NOT be changed. */
+#define PNG_TEXT_COMPRESSION_NONE_WR -3
+#define PNG_TEXT_COMPRESSION_zTXt_WR -2
+#define PNG_TEXT_COMPRESSION_NONE    -1
+#define PNG_TEXT_COMPRESSION_zTXt     0
+#define PNG_ITXT_COMPRESSION_NONE     1
+#define PNG_ITXT_COMPRESSION_zTXt     2
+#define PNG_TEXT_COMPRESSION_LAST     3  /* Not a valid value */
+
+/* png_time is a way to hold the time in an machine independent way.
+ * Two conversions are provided, both from time_t and struct tm.  There
+ * is no portable way to convert to either of these structures, as far
+ * as I know.  If you know of a portable way, send it to me.  As a side
+ * note - PNG has always been Year 2000 compliant!
+ */
+typedef struct png_time_struct
+{
+   png_uint_16 year; /* full year, as in, 1995 */
+   png_byte month;   /* month of year, 1 - 12 */
+   png_byte day;     /* day of month, 1 - 31 */
+   png_byte hour;    /* hour of day, 0 - 23 */
+   png_byte minute;  /* minute of hour, 0 - 59 */
+   png_byte second;  /* second of minute, 0 - 60 (for leap seconds) */
+} png_time;
+typedef png_time FAR * png_timep;
+typedef png_time FAR * FAR * png_timepp;
+
+#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+/* png_unknown_chunk is a structure to hold queued chunks for which there is
+ * no specific support.  The idea is that we can use this to queue
+ * up private chunks for output even though the library doesn't actually
+ * know about their semantics.
+ */
+typedef struct png_unknown_chunk_t
+{
+    png_byte name[5];
+    png_byte *data;
+    png_size_t size;
+
+    /* libpng-using applications should NOT directly modify this byte. */
+    png_byte location; /* mode of operation at read time */
+}
+png_unknown_chunk;
+typedef png_unknown_chunk FAR * png_unknown_chunkp;
+typedef png_unknown_chunk FAR * FAR * png_unknown_chunkpp;
+#endif
+
+/* png_info is a structure that holds the information in a PNG file so
+ * that the application can find out the characteristics of the image.
+ * If you are reading the file, this structure will tell you what is
+ * in the PNG file.  If you are writing the file, fill in the information
+ * you want to put into the PNG file, then call png_write_info().
+ * The names chosen should be very close to the PNG specification, so
+ * consult that document for information about the meaning of each field.
+ *
+ * With libpng < 0.95, it was only possible to directly set and read the
+ * the values in the png_info_struct, which meant that the contents and
+ * order of the values had to remain fixed.  With libpng 0.95 and later,
+ * however, there are now functions that abstract the contents of
+ * png_info_struct from the application, so this makes it easier to use
+ * libpng with dynamic libraries, and even makes it possible to use
+ * libraries that don't have all of the libpng ancillary chunk-handing
+ * functionality.
+ *
+ * In any case, the order of the parameters in png_info_struct should NOT
+ * be changed for as long as possible to keep compatibility with applications
+ * that use the old direct-access method with png_info_struct.
+ *
+ * The following members may have allocated storage attached that should be
+ * cleaned up before the structure is discarded: palette, trans, text,
+ * pcal_purpose, pcal_units, pcal_params, hist, iccp_name, iccp_profile,
+ * splt_palettes, scal_unit, row_pointers, and unknowns.   By default, these
+ * are automatically freed when the info structure is deallocated, if they were
+ * allocated internally by libpng.  This behavior can be changed by means
+ * of the png_data_freer() function.
+ *
+ * More allocation details: all the chunk-reading functions that
+ * change these members go through the corresponding png_set_*
+ * functions.  A function to clear these members is available: see
+ * png_free_data().  The png_set_* functions do not depend on being
+ * able to point info structure members to any of the storage they are
+ * passed (they make their own copies), EXCEPT that the png_set_text
+ * functions use the same storage passed to them in the text_ptr or
+ * itxt_ptr structure argument, and the png_set_rows and png_set_unknowns
+ * functions do not make their own copies.
+ */
+typedef struct png_info_struct
+{
+   /* the following are necessary for every PNG file */
+   png_uint_32 width;       /* width of image in pixels (from IHDR) */
+   png_uint_32 height;      /* height of image in pixels (from IHDR) */
+   png_uint_32 valid;       /* valid chunk data (see PNG_INFO_ below) */
+   png_uint_32 rowbytes;    /* bytes needed to hold an untransformed row */
+   png_colorp palette;      /* array of color values (valid & PNG_INFO_PLTE) */
+   png_uint_16 num_palette; /* number of color entries in "palette" (PLTE) */
+   png_uint_16 num_trans;   /* number of transparent palette color (tRNS) */
+   png_byte bit_depth;      /* 1, 2, 4, 8, or 16 bits/channel (from IHDR) */
+   png_byte color_type;     /* see PNG_COLOR_TYPE_ below (from IHDR) */
+   /* The following three should have been named *_method not *_type */
+   png_byte compression_type; /* must be PNG_COMPRESSION_TYPE_BASE (IHDR) */
+   png_byte filter_type;    /* must be PNG_FILTER_TYPE_BASE (from IHDR) */
+   png_byte interlace_type; /* One of PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */
+
+   /* The following is informational only on read, and not used on writes. */
+   png_byte channels;       /* number of data channels per pixel (1, 2, 3, 4) */
+   png_byte pixel_depth;    /* number of bits per pixel */
+   png_byte spare_byte;     /* to align the data, and for future use */
+   png_byte signature[8];   /* magic bytes read by libpng from start of file */
+
+   /* The rest of the data is optional.  If you are reading, check the
+    * valid field to see if the information in these are valid.  If you
+    * are writing, set the valid field to those chunks you want written,
+    * and initialize the appropriate fields below.
+    */
+
+#if defined(PNG_gAMA_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED)
+   /* The gAMA chunk describes the gamma characteristics of the system
+    * on which the image was created, normally in the range [1.0, 2.5].
+    * Data is valid if (valid & PNG_INFO_gAMA) is non-zero.
+    */
+   float gamma; /* gamma value of image, if (valid & PNG_INFO_gAMA) */
+#endif
+
+#if defined(PNG_sRGB_SUPPORTED)
+    /* GR-P, 0.96a */
+    /* Data valid if (valid & PNG_INFO_sRGB) non-zero. */
+   png_byte srgb_intent; /* sRGB rendering intent [0, 1, 2, or 3] */
+#endif
+
+#if defined(PNG_TEXT_SUPPORTED)
+   /* The tEXt, and zTXt chunks contain human-readable textual data in
+    * uncompressed, compressed, and optionally compressed forms, respectively.
+    * The data in "text" is an array of pointers to uncompressed,
+    * null-terminated C strings. Each chunk has a keyword that describes the
+    * textual data contained in that chunk.  Keywords are not required to be
+    * unique, and the text string may be empty.  Any number of text chunks may
+    * be in an image.
+    */
+   int num_text; /* number of comments read/to write */
+   int max_text; /* current size of text array */
+   png_textp text; /* array of comments read/to write */
+#endif /* PNG_TEXT_SUPPORTED */
+
+#if defined(PNG_tIME_SUPPORTED)
+   /* The tIME chunk holds the last time the displayed image data was
+    * modified.  See the png_time struct for the contents of this struct.
+    */
+   png_time mod_time;
+#endif
+
+#if defined(PNG_sBIT_SUPPORTED)
+   /* The sBIT chunk specifies the number of significant high-order bits
+    * in the pixel data.  Values are in the range [1, bit_depth], and are
+    * only specified for the channels in the pixel data.  The contents of
+    * the low-order bits is not specified.  Data is valid if
+    * (valid & PNG_INFO_sBIT) is non-zero.
+    */
+   png_color_8 sig_bit; /* significant bits in color channels */
+#endif
+
+#if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_EXPAND_SUPPORTED) || \
+defined(PNG_READ_BACKGROUND_SUPPORTED)
+   /* The tRNS chunk supplies transparency data for paletted images and
+    * other image types that don't need a full alpha channel.  There are
+    * "num_trans" transparency values for a paletted image, stored in the
+    * same order as the palette colors, starting from index 0.  Values
+    * for the data are in the range [0, 255], ranging from fully transparent
+    * to fully opaque, respectively.  For non-paletted images, there is a
+    * single color specified that should be treated as fully transparent.
+    * Data is valid if (valid & PNG_INFO_tRNS) is non-zero.
+    */
+   png_bytep trans; /* transparent values for paletted image */
+   png_color_16 trans_values; /* transparent color for non-palette image */
+#endif
+
+#if defined(PNG_bKGD_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
+   /* The bKGD chunk gives the suggested image background color if the
+    * display program does not have its own background color and the image
+    * is needs to composited onto a background before display.  The colors
+    * in "background" are normally in the same color space/depth as the
+    * pixel data.  Data is valid if (valid & PNG_INFO_bKGD) is non-zero.
+    */
+   png_color_16 background;
+#endif
+
+#if defined(PNG_oFFs_SUPPORTED)
+   /* The oFFs chunk gives the offset in "offset_unit_type" units rightwards
+    * and downwards from the top-left corner of the display, page, or other
+    * application-specific co-ordinate space.  See the PNG_OFFSET_ defines
+    * below for the unit types.  Valid if (valid & PNG_INFO_oFFs) non-zero.
+    */
+   png_int_32 x_offset; /* x offset on page */
+   png_int_32 y_offset; /* y offset on page */
+   png_byte offset_unit_type; /* offset units type */
+#endif
+
+#if defined(PNG_pHYs_SUPPORTED)
+   /* The pHYs chunk gives the physical pixel density of the image for
+    * display or printing in "phys_unit_type" units (see PNG_RESOLUTION_
+    * defines below).  Data is valid if (valid & PNG_INFO_pHYs) is non-zero.
+    */
+   png_uint_32 x_pixels_per_unit; /* horizontal pixel density */
+   png_uint_32 y_pixels_per_unit; /* vertical pixel density */
+   png_byte phys_unit_type; /* resolution type (see PNG_RESOLUTION_ below) */
+#endif
+
+#if defined(PNG_hIST_SUPPORTED)
+   /* The hIST chunk contains the relative frequency or importance of the
+    * various palette entries, so that a viewer can intelligently select a
+    * reduced-color palette, if required.  Data is an array of "num_palette"
+    * values in the range [0,65535]. Data valid if (valid & PNG_INFO_hIST)
+    * is non-zero.
+    */
+   png_uint_16p hist;
+#endif
+
+#ifdef PNG_cHRM_SUPPORTED
+   /* The cHRM chunk describes the CIE color characteristics of the monitor
+    * on which the PNG was created.  This data allows the viewer to do gamut
+    * mapping of the input image to ensure that the viewer sees the same
+    * colors in the image as the creator.  Values are in the range
+    * [0.0, 0.8].  Data valid if (valid & PNG_INFO_cHRM) non-zero.
+    */
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+   float x_white;
+   float y_white;
+   float x_red;
+   float y_red;
+   float x_green;
+   float y_green;
+   float x_blue;
+   float y_blue;
+#endif
+#endif
+
+#if defined(PNG_pCAL_SUPPORTED)
+   /* The pCAL chunk describes a transformation between the stored pixel
+    * values and original physical data values used to create the image.
+    * The integer range [0, 2^bit_depth - 1] maps to the floating-point
+    * range given by [pcal_X0, pcal_X1], and are further transformed by a
+    * (possibly non-linear) transformation function given by "pcal_type"
+    * and "pcal_params" into "pcal_units".  Please see the PNG_EQUATION_
+    * defines below, and the PNG-Group's PNG extensions document for a
+    * complete description of the transformations and how they should be
+    * implemented, and for a description of the ASCII parameter strings.
+    * Data values are valid if (valid & PNG_INFO_pCAL) non-zero.
+    */
+   png_charp pcal_purpose;  /* pCAL chunk description string */
+   png_int_32 pcal_X0;      /* minimum value */
+   png_int_32 pcal_X1;      /* maximum value */
+   png_charp pcal_units;    /* Latin-1 string giving physical units */
+   png_charpp pcal_params;  /* ASCII strings containing parameter values */
+   png_byte pcal_type;      /* equation type (see PNG_EQUATION_ below) */
+   png_byte pcal_nparams;   /* number of parameters given in pcal_params */
+#endif
+
+/* New members added in libpng-1.0.6 */
+#ifdef PNG_FREE_ME_SUPPORTED
+   png_uint_32 free_me;     /* flags items libpng is responsible for freeing */
+#endif
+
+#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+   /* storage for unknown chunks that the library doesn't recognize. */
+   png_unknown_chunkp unknown_chunks;
+   png_size_t unknown_chunks_num;
+#endif
+
+#if defined(PNG_iCCP_SUPPORTED)
+   /* iCCP chunk data. */
+   png_charp iccp_name;     /* profile name */
+   png_charp iccp_profile;  /* International Color Consortium profile data */
+                            /* Note to maintainer: should be png_bytep */
+   png_uint_32 iccp_proflen;  /* ICC profile data length */
+   png_byte iccp_compression; /* Always zero */
+#endif
+
+#if defined(PNG_sPLT_SUPPORTED)
+   /* data on sPLT chunks (there may be more than one). */
+   png_sPLT_tp splt_palettes;
+   png_uint_32 splt_palettes_num;
+#endif
+
+#if defined(PNG_sCAL_SUPPORTED)
+   /* The sCAL chunk describes the actual physical dimensions of the
+    * subject matter of the graphic.  The chunk contains a unit specification
+    * a byte value, and two ASCII strings representing floating-point
+    * values.  The values are width and height corresponsing to one pixel
+    * in the image.  This external representation is converted to double
+    * here.  Data values are valid if (valid & PNG_INFO_sCAL) is non-zero.
+    */
+   png_byte scal_unit;         /* unit of physical scale */
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+   double scal_pixel_width;    /* width of one pixel */
+   double scal_pixel_height;   /* height of one pixel */
+#endif
+#ifdef PNG_FIXED_POINT_SUPPORTED
+   png_charp scal_s_width;     /* string containing height */
+   png_charp scal_s_height;    /* string containing width */
+#endif
+#endif
+
+#if defined(PNG_INFO_IMAGE_SUPPORTED)
+   /* Memory has been allocated if (valid & PNG_ALLOCATED_INFO_ROWS) non-zero */
+   /* Data valid if (valid & PNG_INFO_IDAT) non-zero */
+   png_bytepp row_pointers;        /* the image bits */
+#endif
+
+#if defined(PNG_FIXED_POINT_SUPPORTED) && defined(PNG_gAMA_SUPPORTED)
+   png_fixed_point int_gamma; /* gamma of image, if (valid & PNG_INFO_gAMA) */
+#endif
+
+#if defined(PNG_cHRM_SUPPORTED) && defined(PNG_FIXED_POINT_SUPPORTED)
+   png_fixed_point int_x_white;
+   png_fixed_point int_y_white;
+   png_fixed_point int_x_red;
+   png_fixed_point int_y_red;
+   png_fixed_point int_x_green;
+   png_fixed_point int_y_green;
+   png_fixed_point int_x_blue;
+   png_fixed_point int_y_blue;
+#endif
+
+} png_info;
+
+typedef png_info FAR * png_infop;
+typedef png_info FAR * FAR * png_infopp;
+
+/* Maximum positive integer used in PNG is (2^31)-1 */
+#define PNG_UINT_31_MAX ((png_uint_32)0x7fffffffL)
+#define PNG_UINT_32_MAX ((png_uint_32)(-1))
+#define PNG_SIZE_MAX ((png_size_t)(-1))
+#if defined(PNG_1_0_X) || defined (PNG_1_2_X)
+/* PNG_MAX_UINT is deprecated; use PNG_UINT_31_MAX instead. */
+#define PNG_MAX_UINT PNG_UINT_31_MAX
+#endif
+
+/* These describe the color_type field in png_info. */
+/* color type masks */
+#define PNG_COLOR_MASK_PALETTE    1
+#define PNG_COLOR_MASK_COLOR      2
+#define PNG_COLOR_MASK_ALPHA      4
+
+/* color types.  Note that not all combinations are legal */
+#define PNG_COLOR_TYPE_GRAY 0
+#define PNG_COLOR_TYPE_PALETTE  (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_PALETTE)
+#define PNG_COLOR_TYPE_RGB        (PNG_COLOR_MASK_COLOR)
+#define PNG_COLOR_TYPE_RGB_ALPHA  (PNG_COLOR_MASK_COLOR | PNG_COLOR_MASK_ALPHA)
+#define PNG_COLOR_TYPE_GRAY_ALPHA (PNG_COLOR_MASK_ALPHA)
+/* aliases */
+#define PNG_COLOR_TYPE_RGBA  PNG_COLOR_TYPE_RGB_ALPHA
+#define PNG_COLOR_TYPE_GA  PNG_COLOR_TYPE_GRAY_ALPHA
+
+/* This is for compression type. PNG 1.0-1.2 only define the single type. */
+#define PNG_COMPRESSION_TYPE_BASE 0 /* Deflate method 8, 32K window */
+#define PNG_COMPRESSION_TYPE_DEFAULT PNG_COMPRESSION_TYPE_BASE
+
+/* This is for filter type. PNG 1.0-1.2 only define the single type. */
+#define PNG_FILTER_TYPE_BASE      0 /* Single row per-byte filtering */
+#define PNG_INTRAPIXEL_DIFFERENCING 64 /* Used only in MNG datastreams */
+#define PNG_FILTER_TYPE_DEFAULT   PNG_FILTER_TYPE_BASE
+
+/* These are for the interlacing type.  These values should NOT be changed. */
+#define PNG_INTERLACE_NONE        0 /* Non-interlaced image */
+#define PNG_INTERLACE_ADAM7       1 /* Adam7 interlacing */
+#define PNG_INTERLACE_LAST        2 /* Not a valid value */
+
+/* These are for the oFFs chunk.  These values should NOT be changed. */
+#define PNG_OFFSET_PIXEL          0 /* Offset in pixels */
+#define PNG_OFFSET_MICROMETER     1 /* Offset in micrometers (1/10^6 meter) */
+#define PNG_OFFSET_LAST           2 /* Not a valid value */
+
+/* These are for the pCAL chunk.  These values should NOT be changed. */
+#define PNG_EQUATION_LINEAR       0 /* Linear transformation */
+#define PNG_EQUATION_BASE_E       1 /* Exponential base e transform */
+#define PNG_EQUATION_ARBITRARY    2 /* Arbitrary base exponential transform */
+#define PNG_EQUATION_HYPERBOLIC   3 /* Hyperbolic sine transformation */
+#define PNG_EQUATION_LAST         4 /* Not a valid value */
+
+/* These are for the sCAL chunk.  These values should NOT be changed. */
+#define PNG_SCALE_UNKNOWN         0 /* unknown unit (image scale) */
+#define PNG_SCALE_METER           1 /* meters per pixel */
+#define PNG_SCALE_RADIAN          2 /* radians per pixel */
+#define PNG_SCALE_LAST            3 /* Not a valid value */
+
+/* These are for the pHYs chunk.  These values should NOT be changed. */
+#define PNG_RESOLUTION_UNKNOWN    0 /* pixels/unknown unit (aspect ratio) */
+#define PNG_RESOLUTION_METER      1 /* pixels/meter */
+#define PNG_RESOLUTION_LAST       2 /* Not a valid value */
+
+/* These are for the sRGB chunk.  These values should NOT be changed. */
+#define PNG_sRGB_INTENT_PERCEPTUAL 0
+#define PNG_sRGB_INTENT_RELATIVE   1
+#define PNG_sRGB_INTENT_SATURATION 2
+#define PNG_sRGB_INTENT_ABSOLUTE   3
+#define PNG_sRGB_INTENT_LAST       4 /* Not a valid value */
+
+/* This is for text chunks */
+#define PNG_KEYWORD_MAX_LENGTH     79
+
+/* Maximum number of entries in PLTE/sPLT/tRNS arrays */
+#define PNG_MAX_PALETTE_LENGTH    256
+
+/* These determine if an ancillary chunk's data has been successfully read
+ * from the PNG header, or if the application has filled in the corresponding
+ * data in the info_struct to be written into the output file.  The values
+ * of the PNG_INFO_<chunk> defines should NOT be changed.
+ */
+#define PNG_INFO_gAMA 0x0001
+#define PNG_INFO_sBIT 0x0002
+#define PNG_INFO_cHRM 0x0004
+#define PNG_INFO_PLTE 0x0008
+#define PNG_INFO_tRNS 0x0010
+#define PNG_INFO_bKGD 0x0020
+#define PNG_INFO_hIST 0x0040
+#define PNG_INFO_pHYs 0x0080
+#define PNG_INFO_oFFs 0x0100
+#define PNG_INFO_tIME 0x0200
+#define PNG_INFO_pCAL 0x0400
+#define PNG_INFO_sRGB 0x0800   /* GR-P, 0.96a */
+#define PNG_INFO_iCCP 0x1000   /* ESR, 1.0.6 */
+#define PNG_INFO_sPLT 0x2000   /* ESR, 1.0.6 */
+#define PNG_INFO_sCAL 0x4000   /* ESR, 1.0.6 */
+#define PNG_INFO_IDAT 0x8000L  /* ESR, 1.0.6 */
+
+/* This is used for the transformation routines, as some of them
+ * change these values for the row.  It also should enable using
+ * the routines for other purposes.
+ */
+typedef struct png_row_info_struct
+{
+   png_uint_32 width; /* width of row */
+   png_uint_32 rowbytes; /* number of bytes in row */
+   png_byte color_type; /* color type of row */
+   png_byte bit_depth; /* bit depth of row */
+   png_byte channels; /* number of channels (1, 2, 3, or 4) */
+   png_byte pixel_depth; /* bits per pixel (depth * channels) */
+} png_row_info;
+
+typedef png_row_info FAR * png_row_infop;
+typedef png_row_info FAR * FAR * png_row_infopp;
+
+/* These are the function types for the I/O functions and for the functions
+ * that allow the user to override the default I/O functions with his or her
+ * own.  The png_error_ptr type should match that of user-supplied warning
+ * and error functions, while the png_rw_ptr type should match that of the
+ * user read/write data functions.
+ */
+typedef struct png_struct_def png_struct;
+typedef png_struct FAR * png_structp;
+
+typedef void (PNGAPI *png_error_ptr) PNGARG((png_structp, png_const_charp));
+typedef void (PNGAPI *png_rw_ptr) PNGARG((png_structp, png_bytep, png_size_t));
+typedef void (PNGAPI *png_flush_ptr) PNGARG((png_structp));
+typedef void (PNGAPI *png_read_status_ptr) PNGARG((png_structp, png_uint_32,
+   int));
+typedef void (PNGAPI *png_write_status_ptr) PNGARG((png_structp, png_uint_32,
+   int));
+
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+typedef void (PNGAPI *png_progressive_info_ptr) PNGARG((png_structp, png_infop));
+typedef void (PNGAPI *png_progressive_end_ptr) PNGARG((png_structp, png_infop));
+typedef void (PNGAPI *png_progressive_row_ptr) PNGARG((png_structp, png_bytep,
+   png_uint_32, int));
+#endif
+
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
+    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) || \
+    defined(PNG_LEGACY_SUPPORTED)
+typedef void (PNGAPI *png_user_transform_ptr) PNGARG((png_structp,
+    png_row_infop, png_bytep));
+#endif
+
+#if defined(PNG_USER_CHUNKS_SUPPORTED)
+typedef int (PNGAPI *png_user_chunk_ptr) PNGARG((png_structp, png_unknown_chunkp));
+#endif
+#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+typedef void (PNGAPI *png_unknown_chunk_ptr) PNGARG((png_structp));
+#endif
+
+/* Transform masks for the high-level interface */
+#define PNG_TRANSFORM_IDENTITY       0x0000    /* read and write */
+#define PNG_TRANSFORM_STRIP_16       0x0001    /* read only */
+#define PNG_TRANSFORM_STRIP_ALPHA    0x0002    /* read only */
+#define PNG_TRANSFORM_PACKING        0x0004    /* read and write */
+#define PNG_TRANSFORM_PACKSWAP       0x0008    /* read and write */
+#define PNG_TRANSFORM_EXPAND         0x0010    /* read only */
+#define PNG_TRANSFORM_INVERT_MONO    0x0020    /* read and write */
+#define PNG_TRANSFORM_SHIFT          0x0040    /* read and write */
+#define PNG_TRANSFORM_BGR            0x0080    /* read and write */
+#define PNG_TRANSFORM_SWAP_ALPHA     0x0100    /* read and write */
+#define PNG_TRANSFORM_SWAP_ENDIAN    0x0200    /* read and write */
+#define PNG_TRANSFORM_INVERT_ALPHA   0x0400    /* read and write */
+#define PNG_TRANSFORM_STRIP_FILLER   0x0800    /* WRITE only */
+
+/* Flags for MNG supported features */
+#define PNG_FLAG_MNG_EMPTY_PLTE     0x01
+#define PNG_FLAG_MNG_FILTER_64      0x04
+#define PNG_ALL_MNG_FEATURES        0x05
+
+typedef png_voidp (*png_malloc_ptr) PNGARG((png_structp, png_size_t));
+typedef void (*png_free_ptr) PNGARG((png_structp, png_voidp));
+
+/* The structure that holds the information to read and write PNG files.
+ * The only people who need to care about what is inside of this are the
+ * people who will be modifying the library for their own special needs.
+ * It should NOT be accessed directly by an application, except to store
+ * the jmp_buf.
+ */
+
+struct png_struct_def
+{
+#ifdef PNG_SETJMP_SUPPORTED
+   jmp_buf jmpbuf;            /* used in png_error */
+#endif
+   png_error_ptr error_fn;    /* function for printing errors and aborting */
+   png_error_ptr warning_fn;  /* function for printing warnings */
+   png_voidp error_ptr;       /* user supplied struct for error functions */
+   png_rw_ptr write_data_fn;  /* function for writing output data */
+   png_rw_ptr read_data_fn;   /* function for reading input data */
+   png_voidp io_ptr;          /* ptr to application struct for I/O functions */
+
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
+   png_user_transform_ptr read_user_transform_fn; /* user read transform */
+#endif
+
+#if defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
+   png_user_transform_ptr write_user_transform_fn; /* user write transform */
+#endif
+
+/* These were added in libpng-1.0.2 */
+#if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
+    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
+   png_voidp user_transform_ptr; /* user supplied struct for user transform */
+   png_byte user_transform_depth;    /* bit depth of user transformed pixels */
+   png_byte user_transform_channels; /* channels in user transformed pixels */
+#endif
+#endif
+
+   png_uint_32 mode;          /* tells us where we are in the PNG file */
+   png_uint_32 flags;         /* flags indicating various things to libpng */
+   png_uint_32 transformations; /* which transformations to perform */
+
+   z_stream zstream;          /* pointer to decompression structure (below) */
+   png_bytep zbuf;            /* buffer for zlib */
+   png_size_t zbuf_size;      /* size of zbuf */
+   int zlib_level;            /* holds zlib compression level */
+   int zlib_method;           /* holds zlib compression method */
+   int zlib_window_bits;      /* holds zlib compression window bits */
+   int zlib_mem_level;        /* holds zlib compression memory level */
+   int zlib_strategy;         /* holds zlib compression strategy */
+
+   png_uint_32 width;         /* width of image in pixels */
+   png_uint_32 height;        /* height of image in pixels */
+   png_uint_32 num_rows;      /* number of rows in current pass */
+   png_uint_32 usr_width;     /* width of row at start of write */
+   png_uint_32 rowbytes;      /* size of row in bytes */
+   png_uint_32 irowbytes;     /* size of current interlaced row in bytes */
+   png_uint_32 iwidth;        /* width of current interlaced row in pixels */
+   png_uint_32 row_number;    /* current row in interlace pass */
+   png_bytep prev_row;        /* buffer to save previous (unfiltered) row */
+   png_bytep row_buf;         /* buffer to save current (unfiltered) row */
+   png_bytep sub_row;         /* buffer to save "sub" row when filtering */
+   png_bytep up_row;          /* buffer to save "up" row when filtering */
+   png_bytep avg_row;         /* buffer to save "avg" row when filtering */
+   png_bytep paeth_row;       /* buffer to save "Paeth" row when filtering */
+   png_row_info row_info;     /* used for transformation routines */
+
+   png_uint_32 idat_size;     /* current IDAT size for read */
+   png_uint_32 crc;           /* current chunk CRC value */
+   png_colorp palette;        /* palette from the input file */
+   png_uint_16 num_palette;   /* number of color entries in palette */
+   png_uint_16 num_trans;     /* number of transparency values */
+   png_byte chunk_name[5];    /* null-terminated name of current chunk */
+   png_byte compression;      /* file compression type (always 0) */
+   png_byte filter;           /* file filter type (always 0) */
+   png_byte interlaced;       /* PNG_INTERLACE_NONE, PNG_INTERLACE_ADAM7 */
+   png_byte pass;             /* current interlace pass (0 - 6) */
+   png_byte do_filter;        /* row filter flags (see PNG_FILTER_ below ) */
+   png_byte color_type;       /* color type of file */
+   png_byte bit_depth;        /* bit depth of file */
+   png_byte usr_bit_depth;    /* bit depth of users row */
+   png_byte pixel_depth;      /* number of bits per pixel */
+   png_byte channels;         /* number of channels in file */
+   png_byte usr_channels;     /* channels at start of write */
+   png_byte sig_bytes;        /* magic bytes read/written from start of file */
+
+#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
+#ifdef PNG_LEGACY_SUPPORTED
+   png_byte filler;           /* filler byte for pixel expansion */
+#else
+   png_uint_16 filler;           /* filler bytes for pixel expansion */
+#endif
+#endif
+
+#if defined(PNG_bKGD_SUPPORTED)
+   png_byte background_gamma_type;
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+   float background_gamma;
+#  endif
+   png_color_16 background;   /* background color in screen gamma space */
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+   png_color_16 background_1; /* background normalized to gamma 1.0 */
+#endif
+#endif /* PNG_bKGD_SUPPORTED */
+
+#if defined(PNG_WRITE_FLUSH_SUPPORTED)
+   png_flush_ptr output_flush_fn;/* Function for flushing output */
+   png_uint_32 flush_dist;    /* how many rows apart to flush, 0 - no flush */
+   png_uint_32 flush_rows;    /* number of rows written since last flush */
+#endif
+
+#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
+   int gamma_shift;      /* number of "insignificant" bits 16-bit gamma */
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+   float gamma;          /* file gamma value */
+   float screen_gamma;   /* screen gamma value (display_exponent) */
+#endif
+#endif
+
+#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
+   png_bytep gamma_table;     /* gamma table for 8-bit depth files */
+   png_bytep gamma_from_1;    /* converts from 1.0 to screen */
+   png_bytep gamma_to_1;      /* converts from file to 1.0 */
+   png_uint_16pp gamma_16_table; /* gamma table for 16-bit depth files */
+   png_uint_16pp gamma_16_from_1; /* converts from 1.0 to screen */
+   png_uint_16pp gamma_16_to_1; /* converts from file to 1.0 */
+#endif
+
+#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_sBIT_SUPPORTED)
+   png_color_8 sig_bit;       /* significant bits in each available channel */
+#endif
+
+#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
+   png_color_8 shift;         /* shift for significant bit tranformation */
+#endif
+
+#if defined(PNG_tRNS_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED) \
+ || defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
+   png_bytep trans;           /* transparency values for paletted files */
+   png_color_16 trans_values; /* transparency values for non-paletted files */
+#endif
+
+   png_read_status_ptr read_row_fn;   /* called after each row is decoded */
+   png_write_status_ptr write_row_fn; /* called after each row is encoded */
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+   png_progressive_info_ptr info_fn; /* called after header data fully read */
+   png_progressive_row_ptr row_fn;   /* called after each prog. row is decoded */
+   png_progressive_end_ptr end_fn;   /* called after image is complete */
+   png_bytep save_buffer_ptr;        /* current location in save_buffer */
+   png_bytep save_buffer;            /* buffer for previously read data */
+   png_bytep current_buffer_ptr;     /* current location in current_buffer */
+   png_bytep current_buffer;         /* buffer for recently used data */
+   png_uint_32 push_length;          /* size of current input chunk */
+   png_uint_32 skip_length;          /* bytes to skip in input data */
+   png_size_t save_buffer_size;      /* amount of data now in save_buffer */
+   png_size_t save_buffer_max;       /* total size of save_buffer */
+   png_size_t buffer_size;           /* total amount of available input data */
+   png_size_t current_buffer_size;   /* amount of data now in current_buffer */
+   int process_mode;                 /* what push library is currently doing */
+   int cur_palette;                  /* current push library palette index */
+
+#  if defined(PNG_TEXT_SUPPORTED)
+     png_size_t current_text_size;   /* current size of text input data */
+     png_size_t current_text_left;   /* how much text left to read in input */
+     png_charp current_text;         /* current text chunk buffer */
+     png_charp current_text_ptr;     /* current location in current_text */
+#  endif /* PNG_PROGRESSIVE_READ_SUPPORTED && PNG_TEXT_SUPPORTED */
+
+#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
+
+#if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
+/* for the Borland special 64K segment handler */
+   png_bytepp offset_table_ptr;
+   png_bytep offset_table;
+   png_uint_16 offset_table_number;
+   png_uint_16 offset_table_count;
+   png_uint_16 offset_table_count_free;
+#endif
+
+#if defined(PNG_READ_DITHER_SUPPORTED)
+   png_bytep palette_lookup;         /* lookup table for dithering */
+   png_bytep dither_index;           /* index translation for palette files */
+#endif
+
+#if defined(PNG_READ_DITHER_SUPPORTED) || defined(PNG_hIST_SUPPORTED)
+   png_uint_16p hist;                /* histogram */
+#endif
+
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+   png_byte heuristic_method;        /* heuristic for row filter selection */
+   png_byte num_prev_filters;        /* number of weights for previous rows */
+   png_bytep prev_filters;           /* filter type(s) of previous row(s) */
+   png_uint_16p filter_weights;      /* weight(s) for previous line(s) */
+   png_uint_16p inv_filter_weights;  /* 1/weight(s) for previous line(s) */
+   png_uint_16p filter_costs;        /* relative filter calculation cost */
+   png_uint_16p inv_filter_costs;    /* 1/relative filter calculation cost */
+#endif
+
+#if defined(PNG_TIME_RFC1123_SUPPORTED)
+   png_charp time_buffer;            /* String to hold RFC 1123 time text */
+#endif
+
+/* New members added in libpng-1.0.6 */
+
+#ifdef PNG_FREE_ME_SUPPORTED
+   png_uint_32 free_me;       /* flags items libpng is responsible for freeing */
+#endif
+
+#if defined(PNG_USER_CHUNKS_SUPPORTED)
+   png_voidp user_chunk_ptr;
+   png_user_chunk_ptr read_user_chunk_fn; /* user read chunk handler */
+#endif
+
+#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+   int num_chunk_list;
+   png_bytep chunk_list;
+#endif
+
+/* New members added in libpng-1.0.3 */
+#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+   png_byte rgb_to_gray_status;
+   /* These were changed from png_byte in libpng-1.0.6 */
+   png_uint_16 rgb_to_gray_red_coeff;
+   png_uint_16 rgb_to_gray_green_coeff;
+   png_uint_16 rgb_to_gray_blue_coeff;
+#endif
+
+/* New member added in libpng-1.0.4 (renamed in 1.0.9) */
+#if defined(PNG_MNG_FEATURES_SUPPORTED) || \
+    defined(PNG_READ_EMPTY_PLTE_SUPPORTED) || \
+    defined(PNG_WRITE_EMPTY_PLTE_SUPPORTED)
+/* changed from png_byte to png_uint_32 at version 1.2.0 */
+#ifdef PNG_1_0_X
+   png_byte mng_features_permitted;
+#else
+   png_uint_32 mng_features_permitted;
+#endif /* PNG_1_0_X */
+#endif
+
+/* New member added in libpng-1.0.7 */
+#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
+   png_fixed_point int_gamma;
+#endif
+
+/* New member added in libpng-1.0.9, ifdef'ed out in 1.0.12, enabled in 1.2.0 */
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
+   png_byte filter_type;
+#endif
+
+#if defined(PNG_1_0_X)
+/* New member added in libpng-1.0.10, ifdef'ed out in 1.2.0 */
+   png_uint_32 row_buf_size;
+#endif
+
+/* New members added in libpng-1.2.0 */
+#if defined(PNG_ASSEMBLER_CODE_SUPPORTED)
+#  if !defined(PNG_1_0_X)
+#    if defined(PNG_MMX_CODE_SUPPORTED)
+   png_byte     mmx_bitdepth_threshold;
+   png_uint_32  mmx_rowbytes_threshold;
+#    endif
+   png_uint_32  asm_flags;
+#  endif
+#endif
+
+/* New members added in libpng-1.0.2 but first enabled by default in 1.2.0 */
+#ifdef PNG_USER_MEM_SUPPORTED
+   png_voidp mem_ptr;                /* user supplied struct for mem functions */
+   png_malloc_ptr malloc_fn;         /* function for allocating memory */
+   png_free_ptr free_fn;             /* function for freeing memory */
+#endif
+
+/* New member added in libpng-1.0.13 and 1.2.0 */
+   png_bytep big_row_buf;         /* buffer to save current (unfiltered) row */
+
+#if defined(PNG_READ_DITHER_SUPPORTED)
+/* The following three members were added at version 1.0.14 and 1.2.4 */
+   png_bytep dither_sort;            /* working sort array */
+   png_bytep index_to_palette;       /* where the original index currently is */
+                                     /* in the palette */
+   png_bytep palette_to_index;       /* which original index points to this */
+                                     /* palette color */
+#endif
+
+/* New members added in libpng-1.0.16 and 1.2.6 */
+   png_byte compression_type;
+
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+   png_uint_32 user_width_max;
+   png_uint_32 user_height_max;
+#endif
+
+/* New member added in libpng-1.0.25 and 1.2.17 */
+#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+   /* storage for unknown chunk that the library doesn't recognize. */
+   png_unknown_chunk unknown_chunk;
+#endif
+};
+
+
+/* This triggers a compiler error in png.c, if png.c and png.h
+ * do not agree upon the version number.
+ */
+typedef png_structp version_1_2_19;
+
+typedef png_struct FAR * FAR * png_structpp;
+
+/* Here are the function definitions most commonly used.  This is not
+ * the place to find out how to use libpng.  See libpng.txt for the
+ * full explanation, see example.c for the summary.  This just provides
+ * a simple one line description of the use of each function.
+ */
+
+/* Returns the version number of the library */
+extern PNG_EXPORT(png_uint_32,png_access_version_number) PNGARG((void));
+
+/* Tell lib we have already handled the first <num_bytes> magic bytes.
+ * Handling more than 8 bytes from the beginning of the file is an error.
+ */
+extern PNG_EXPORT(void,png_set_sig_bytes) PNGARG((png_structp png_ptr,
+   int num_bytes));
+
+/* Check sig[start] through sig[start + num_to_check - 1] to see if it's a
+ * PNG file.  Returns zero if the supplied bytes match the 8-byte PNG
+ * signature, and non-zero otherwise.  Having num_to_check == 0 or
+ * start > 7 will always fail (ie return non-zero).
+ */
+extern PNG_EXPORT(int,png_sig_cmp) PNGARG((png_bytep sig, png_size_t start,
+   png_size_t num_to_check));
+
+/* Simple signature checking function.  This is the same as calling
+ * png_check_sig(sig, n) := !png_sig_cmp(sig, 0, n).
+ */
+extern PNG_EXPORT(int,png_check_sig) PNGARG((png_bytep sig, int num));
+
+/* Allocate and initialize png_ptr struct for reading, and any other memory. */
+extern PNG_EXPORT(png_structp,png_create_read_struct)
+   PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,
+   png_error_ptr error_fn, png_error_ptr warn_fn));
+
+/* Allocate and initialize png_ptr struct for writing, and any other memory */
+extern PNG_EXPORT(png_structp,png_create_write_struct)
+   PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,
+   png_error_ptr error_fn, png_error_ptr warn_fn));
+
+#ifdef PNG_WRITE_SUPPORTED
+extern PNG_EXPORT(png_uint_32,png_get_compression_buffer_size)
+   PNGARG((png_structp png_ptr));
+#endif
+
+#ifdef PNG_WRITE_SUPPORTED
+extern PNG_EXPORT(void,png_set_compression_buffer_size)
+   PNGARG((png_structp png_ptr, png_uint_32 size));
+#endif
+
+/* Reset the compression stream */
+extern PNG_EXPORT(int,png_reset_zstream) PNGARG((png_structp png_ptr));
+
+/* New functions added in libpng-1.0.2 (not enabled by default until 1.2.0) */
+#ifdef PNG_USER_MEM_SUPPORTED
+extern PNG_EXPORT(png_structp,png_create_read_struct_2)
+   PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,
+   png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
+   png_malloc_ptr malloc_fn, png_free_ptr free_fn));
+extern PNG_EXPORT(png_structp,png_create_write_struct_2)
+   PNGARG((png_const_charp user_png_ver, png_voidp error_ptr,
+   png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
+   png_malloc_ptr malloc_fn, png_free_ptr free_fn));
+#endif
+
+/* Write a PNG chunk - size, type, (optional) data, CRC. */
+extern PNG_EXPORT(void,png_write_chunk) PNGARG((png_structp png_ptr,
+   png_bytep chunk_name, png_bytep data, png_size_t length));
+
+/* Write the start of a PNG chunk - length and chunk name. */
+extern PNG_EXPORT(void,png_write_chunk_start) PNGARG((png_structp png_ptr,
+   png_bytep chunk_name, png_uint_32 length));
+
+/* Write the data of a PNG chunk started with png_write_chunk_start(). */
+extern PNG_EXPORT(void,png_write_chunk_data) PNGARG((png_structp png_ptr,
+   png_bytep data, png_size_t length));
+
+/* Finish a chunk started with png_write_chunk_start() (includes CRC). */
+extern PNG_EXPORT(void,png_write_chunk_end) PNGARG((png_structp png_ptr));
+
+/* Allocate and initialize the info structure */
+extern PNG_EXPORT(png_infop,png_create_info_struct)
+   PNGARG((png_structp png_ptr));
+
+#if defined(PNG_1_0_X) || defined (PNG_1_2_X)
+/* Initialize the info structure (old interface - DEPRECATED) */
+extern PNG_EXPORT(void,png_info_init) PNGARG((png_infop info_ptr));
+#undef png_info_init
+#define png_info_init(info_ptr) png_info_init_3(&info_ptr,\
+    png_sizeof(png_info));
+#endif
+
+extern PNG_EXPORT(void,png_info_init_3) PNGARG((png_infopp info_ptr,
+    png_size_t png_info_struct_size));
+
+/* Writes all the PNG information before the image. */
+extern PNG_EXPORT(void,png_write_info_before_PLTE) PNGARG((png_structp png_ptr,
+   png_infop info_ptr));
+extern PNG_EXPORT(void,png_write_info) PNGARG((png_structp png_ptr,
+   png_infop info_ptr));
+
+#ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
+/* read the information before the actual image data. */
+extern PNG_EXPORT(void,png_read_info) PNGARG((png_structp png_ptr,
+   png_infop info_ptr));
+#endif
+
+#if defined(PNG_TIME_RFC1123_SUPPORTED)
+extern PNG_EXPORT(png_charp,png_convert_to_rfc1123)
+   PNGARG((png_structp png_ptr, png_timep ptime));
+#endif
+
+#if !defined(_WIN32_WCE)
+/* "time.h" functions are not supported on WindowsCE */
+#if defined(PNG_WRITE_tIME_SUPPORTED)
+/* convert from a struct tm to png_time */
+extern PNG_EXPORT(void,png_convert_from_struct_tm) PNGARG((png_timep ptime,
+   struct tm FAR * ttime));
+
+/* convert from time_t to png_time.  Uses gmtime() */
+extern PNG_EXPORT(void,png_convert_from_time_t) PNGARG((png_timep ptime,
+   time_t ttime));
+#endif /* PNG_WRITE_tIME_SUPPORTED */
+#endif /* _WIN32_WCE */
+
+#if defined(PNG_READ_EXPAND_SUPPORTED)
+/* Expand data to 24-bit RGB, or 8-bit grayscale, with alpha if available. */
+extern PNG_EXPORT(void,png_set_expand) PNGARG((png_structp png_ptr));
+#if !defined(PNG_1_0_X)
+extern PNG_EXPORT(void,png_set_expand_gray_1_2_4_to_8) PNGARG((png_structp
+  png_ptr));
+#endif
+extern PNG_EXPORT(void,png_set_palette_to_rgb) PNGARG((png_structp png_ptr));
+extern PNG_EXPORT(void,png_set_tRNS_to_alpha) PNGARG((png_structp png_ptr));
+#if defined(PNG_1_0_X) || defined (PNG_1_2_X)
+/* Deprecated */
+extern PNG_EXPORT(void,png_set_gray_1_2_4_to_8) PNGARG((png_structp png_ptr));
+#endif
+#endif
+
+#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
+/* Use blue, green, red order for pixels. */
+extern PNG_EXPORT(void,png_set_bgr) PNGARG((png_structp png_ptr));
+#endif
+
+#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
+/* Expand the grayscale to 24-bit RGB if necessary. */
+extern PNG_EXPORT(void,png_set_gray_to_rgb) PNGARG((png_structp png_ptr));
+#endif
+
+#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+/* Reduce RGB to grayscale. */
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+extern PNG_EXPORT(void,png_set_rgb_to_gray) PNGARG((png_structp png_ptr,
+   int error_action, double red, double green ));
+#endif
+extern PNG_EXPORT(void,png_set_rgb_to_gray_fixed) PNGARG((png_structp png_ptr,
+   int error_action, png_fixed_point red, png_fixed_point green ));
+extern PNG_EXPORT(png_byte,png_get_rgb_to_gray_status) PNGARG((png_structp
+   png_ptr));
+#endif
+
+extern PNG_EXPORT(void,png_build_grayscale_palette) PNGARG((int bit_depth,
+   png_colorp palette));
+
+#if defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
+extern PNG_EXPORT(void,png_set_strip_alpha) PNGARG((png_structp png_ptr));
+#endif
+
+#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
+    defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
+extern PNG_EXPORT(void,png_set_swap_alpha) PNGARG((png_structp png_ptr));
+#endif
+
+#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
+    defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
+extern PNG_EXPORT(void,png_set_invert_alpha) PNGARG((png_structp png_ptr));
+#endif
+
+#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
+/* Add a filler byte to 8-bit Gray or 24-bit RGB images. */
+extern PNG_EXPORT(void,png_set_filler) PNGARG((png_structp png_ptr,
+   png_uint_32 filler, int flags));
+/* The values of the PNG_FILLER_ defines should NOT be changed */
+#define PNG_FILLER_BEFORE 0
+#define PNG_FILLER_AFTER 1
+/* Add an alpha byte to 8-bit Gray or 24-bit RGB images. */
+#if !defined(PNG_1_0_X)
+extern PNG_EXPORT(void,png_set_add_alpha) PNGARG((png_structp png_ptr,
+   png_uint_32 filler, int flags));
+#endif
+#endif /* PNG_READ_FILLER_SUPPORTED || PNG_WRITE_FILLER_SUPPORTED */
+
+#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
+/* Swap bytes in 16-bit depth files. */
+extern PNG_EXPORT(void,png_set_swap) PNGARG((png_structp png_ptr));
+#endif
+
+#if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
+/* Use 1 byte per pixel in 1, 2, or 4-bit depth files. */
+extern PNG_EXPORT(void,png_set_packing) PNGARG((png_structp png_ptr));
+#endif
+
+#if defined(PNG_READ_PACKSWAP_SUPPORTED) || defined(PNG_WRITE_PACKSWAP_SUPPORTED)
+/* Swap packing order of pixels in bytes. */
+extern PNG_EXPORT(void,png_set_packswap) PNGARG((png_structp png_ptr));
+#endif
+
+#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
+/* Converts files to legal bit depths. */
+extern PNG_EXPORT(void,png_set_shift) PNGARG((png_structp png_ptr,
+   png_color_8p true_bits));
+#endif
+
+#if defined(PNG_READ_INTERLACING_SUPPORTED) || \
+    defined(PNG_WRITE_INTERLACING_SUPPORTED)
+/* Have the code handle the interlacing.  Returns the number of passes. */
+extern PNG_EXPORT(int,png_set_interlace_handling) PNGARG((png_structp png_ptr));
+#endif
+
+#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
+/* Invert monochrome files */
+extern PNG_EXPORT(void,png_set_invert_mono) PNGARG((png_structp png_ptr));
+#endif
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+/* Handle alpha and tRNS by replacing with a background color. */
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+extern PNG_EXPORT(void,png_set_background) PNGARG((png_structp png_ptr,
+   png_color_16p background_color, int background_gamma_code,
+   int need_expand, double background_gamma));
+#endif
+#define PNG_BACKGROUND_GAMMA_UNKNOWN 0
+#define PNG_BACKGROUND_GAMMA_SCREEN  1
+#define PNG_BACKGROUND_GAMMA_FILE    2
+#define PNG_BACKGROUND_GAMMA_UNIQUE  3
+#endif
+
+#if defined(PNG_READ_16_TO_8_SUPPORTED)
+/* strip the second byte of information from a 16-bit depth file. */
+extern PNG_EXPORT(void,png_set_strip_16) PNGARG((png_structp png_ptr));
+#endif
+
+#if defined(PNG_READ_DITHER_SUPPORTED)
+/* Turn on dithering, and reduce the palette to the number of colors available. */
+extern PNG_EXPORT(void,png_set_dither) PNGARG((png_structp png_ptr,
+   png_colorp palette, int num_palette, int maximum_colors,
+   png_uint_16p histogram, int full_dither));
+#endif
+
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+/* Handle gamma correction. Screen_gamma=(display_exponent) */
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+extern PNG_EXPORT(void,png_set_gamma) PNGARG((png_structp png_ptr,
+   double screen_gamma, double default_file_gamma));
+#endif
+#endif
+
+#if defined(PNG_1_0_X) || defined (PNG_1_2_X)
+#if defined(PNG_READ_EMPTY_PLTE_SUPPORTED) || \
+    defined(PNG_WRITE_EMPTY_PLTE_SUPPORTED)
+/* Permit or disallow empty PLTE (0: not permitted, 1: permitted) */
+/* Deprecated and will be removed.  Use png_permit_mng_features() instead. */
+extern PNG_EXPORT(void,png_permit_empty_plte) PNGARG((png_structp png_ptr,
+   int empty_plte_permitted));
+#endif
+#endif
+
+#if defined(PNG_WRITE_FLUSH_SUPPORTED)
+/* Set how many lines between output flushes - 0 for no flushing */
+extern PNG_EXPORT(void,png_set_flush) PNGARG((png_structp png_ptr, int nrows));
+/* Flush the current PNG output buffer */
+extern PNG_EXPORT(void,png_write_flush) PNGARG((png_structp png_ptr));
+#endif
+
+/* optional update palette with requested transformations */
+extern PNG_EXPORT(void,png_start_read_image) PNGARG((png_structp png_ptr));
+
+/* optional call to update the users info structure */
+extern PNG_EXPORT(void,png_read_update_info) PNGARG((png_structp png_ptr,
+   png_infop info_ptr));
+
+#ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
+/* read one or more rows of image data. */
+extern PNG_EXPORT(void,png_read_rows) PNGARG((png_structp png_ptr,
+   png_bytepp row, png_bytepp display_row, png_uint_32 num_rows));
+#endif
+
+#ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
+/* read a row of data. */
+extern PNG_EXPORT(void,png_read_row) PNGARG((png_structp png_ptr,
+   png_bytep row,
+   png_bytep display_row));
+#endif
+
+#ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
+/* read the whole image into memory at once. */
+extern PNG_EXPORT(void,png_read_image) PNGARG((png_structp png_ptr,
+   png_bytepp image));
+#endif
+
+/* write a row of image data */
+extern PNG_EXPORT(void,png_write_row) PNGARG((png_structp png_ptr,
+   png_bytep row));
+
+/* write a few rows of image data */
+extern PNG_EXPORT(void,png_write_rows) PNGARG((png_structp png_ptr,
+   png_bytepp row, png_uint_32 num_rows));
+
+/* write the image data */
+extern PNG_EXPORT(void,png_write_image) PNGARG((png_structp png_ptr,
+   png_bytepp image));
+
+/* writes the end of the PNG file. */
+extern PNG_EXPORT(void,png_write_end) PNGARG((png_structp png_ptr,
+   png_infop info_ptr));
+
+#ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
+/* read the end of the PNG file. */
+extern PNG_EXPORT(void,png_read_end) PNGARG((png_structp png_ptr,
+   png_infop info_ptr));
+#endif
+
+/* free any memory associated with the png_info_struct */
+extern PNG_EXPORT(void,png_destroy_info_struct) PNGARG((png_structp png_ptr,
+   png_infopp info_ptr_ptr));
+
+/* free any memory associated with the png_struct and the png_info_structs */
+extern PNG_EXPORT(void,png_destroy_read_struct) PNGARG((png_structpp
+   png_ptr_ptr, png_infopp info_ptr_ptr, png_infopp end_info_ptr_ptr));
+
+/* free all memory used by the read (old method - NOT DLL EXPORTED) */
+extern void png_read_destroy PNGARG((png_structp png_ptr, png_infop info_ptr,
+   png_infop end_info_ptr));
+
+/* free any memory associated with the png_struct and the png_info_structs */
+extern PNG_EXPORT(void,png_destroy_write_struct)
+   PNGARG((png_structpp png_ptr_ptr, png_infopp info_ptr_ptr));
+
+/* free any memory used in png_ptr struct (old method - NOT DLL EXPORTED) */
+extern void png_write_destroy PNGARG((png_structp png_ptr));
+
+/* set the libpng method of handling chunk CRC errors */
+extern PNG_EXPORT(void,png_set_crc_action) PNGARG((png_structp png_ptr,
+   int crit_action, int ancil_action));
+
+/* Values for png_set_crc_action() to say how to handle CRC errors in
+ * ancillary and critical chunks, and whether to use the data contained
+ * therein.  Note that it is impossible to "discard" data in a critical
+ * chunk.  For versions prior to 0.90, the action was always error/quit,
+ * whereas in version 0.90 and later, the action for CRC errors in ancillary
+ * chunks is warn/discard.  These values should NOT be changed.
+ *
+ *      value                       action:critical     action:ancillary
+ */
+#define PNG_CRC_DEFAULT       0  /* error/quit          warn/discard data */
+#define PNG_CRC_ERROR_QUIT    1  /* error/quit          error/quit        */
+#define PNG_CRC_WARN_DISCARD  2  /* (INVALID)           warn/discard data */
+#define PNG_CRC_WARN_USE      3  /* warn/use data       warn/use data     */
+#define PNG_CRC_QUIET_USE     4  /* quiet/use data      quiet/use data    */
+#define PNG_CRC_NO_CHANGE     5  /* use current value   use current value */
+
+/* These functions give the user control over the scan-line filtering in
+ * libpng and the compression methods used by zlib.  These functions are
+ * mainly useful for testing, as the defaults should work with most users.
+ * Those users who are tight on memory or want faster performance at the
+ * expense of compression can modify them.  See the compression library
+ * header file (zlib.h) for an explination of the compression functions.
+ */
+
+/* set the filtering method(s) used by libpng.  Currently, the only valid
+ * value for "method" is 0.
+ */
+extern PNG_EXPORT(void,png_set_filter) PNGARG((png_structp png_ptr, int method,
+   int filters));
+
+/* Flags for png_set_filter() to say which filters to use.  The flags
+ * are chosen so that they don't conflict with real filter types
+ * below, in case they are supplied instead of the #defined constants.
+ * These values should NOT be changed.
+ */
+#define PNG_NO_FILTERS     0x00
+#define PNG_FILTER_NONE    0x08
+#define PNG_FILTER_SUB     0x10
+#define PNG_FILTER_UP      0x20
+#define PNG_FILTER_AVG     0x40
+#define PNG_FILTER_PAETH   0x80
+#define PNG_ALL_FILTERS (PNG_FILTER_NONE | PNG_FILTER_SUB | PNG_FILTER_UP | \
+                         PNG_FILTER_AVG | PNG_FILTER_PAETH)
+
+/* Filter values (not flags) - used in pngwrite.c, pngwutil.c for now.
+ * These defines should NOT be changed.
+ */
+#define PNG_FILTER_VALUE_NONE  0
+#define PNG_FILTER_VALUE_SUB   1
+#define PNG_FILTER_VALUE_UP    2
+#define PNG_FILTER_VALUE_AVG   3
+#define PNG_FILTER_VALUE_PAETH 4
+#define PNG_FILTER_VALUE_LAST  5
+
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED) /* EXPERIMENTAL */
+/* The "heuristic_method" is given by one of the PNG_FILTER_HEURISTIC_
+ * defines, either the default (minimum-sum-of-absolute-differences), or
+ * the experimental method (weighted-minimum-sum-of-absolute-differences).
+ *
+ * Weights are factors >= 1.0, indicating how important it is to keep the
+ * filter type consistent between rows.  Larger numbers mean the current
+ * filter is that many times as likely to be the same as the "num_weights"
+ * previous filters.  This is cumulative for each previous row with a weight.
+ * There needs to be "num_weights" values in "filter_weights", or it can be
+ * NULL if the weights aren't being specified.  Weights have no influence on
+ * the selection of the first row filter.  Well chosen weights can (in theory)
+ * improve the compression for a given image.
+ *
+ * Costs are factors >= 1.0 indicating the relative decoding costs of a
+ * filter type.  Higher costs indicate more decoding expense, and are
+ * therefore less likely to be selected over a filter with lower computational
+ * costs.  There needs to be a value in "filter_costs" for each valid filter
+ * type (given by PNG_FILTER_VALUE_LAST), or it can be NULL if you aren't
+ * setting the costs.  Costs try to improve the speed of decompression without
+ * unduly increasing the compressed image size.
+ *
+ * A negative weight or cost indicates the default value is to be used, and
+ * values in the range [0.0, 1.0) indicate the value is to remain unchanged.
+ * The default values for both weights and costs are currently 1.0, but may
+ * change if good general weighting/cost heuristics can be found.  If both
+ * the weights and costs are set to 1.0, this degenerates the WEIGHTED method
+ * to the UNWEIGHTED method, but with added encoding time/computation.
+ */
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+extern PNG_EXPORT(void,png_set_filter_heuristics) PNGARG((png_structp png_ptr,
+   int heuristic_method, int num_weights, png_doublep filter_weights,
+   png_doublep filter_costs));
+#endif
+#endif /*  PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */
+
+/* Heuristic used for row filter selection.  These defines should NOT be
+ * changed.
+ */
+#define PNG_FILTER_HEURISTIC_DEFAULT    0  /* Currently "UNWEIGHTED" */
+#define PNG_FILTER_HEURISTIC_UNWEIGHTED 1  /* Used by libpng < 0.95 */
+#define PNG_FILTER_HEURISTIC_WEIGHTED   2  /* Experimental feature */
+#define PNG_FILTER_HEURISTIC_LAST       3  /* Not a valid value */
+
+/* Set the library compression level.  Currently, valid values range from
+ * 0 - 9, corresponding directly to the zlib compression levels 0 - 9
+ * (0 - no compression, 9 - "maximal" compression).  Note that tests have
+ * shown that zlib compression levels 3-6 usually perform as well as level 9
+ * for PNG images, and do considerably fewer caclulations.  In the future,
+ * these values may not correspond directly to the zlib compression levels.
+ */
+extern PNG_EXPORT(void,png_set_compression_level) PNGARG((png_structp png_ptr,
+   int level));
+
+extern PNG_EXPORT(void,png_set_compression_mem_level)
+   PNGARG((png_structp png_ptr, int mem_level));
+
+extern PNG_EXPORT(void,png_set_compression_strategy)
+   PNGARG((png_structp png_ptr, int strategy));
+
+extern PNG_EXPORT(void,png_set_compression_window_bits)
+   PNGARG((png_structp png_ptr, int window_bits));
+
+extern PNG_EXPORT(void,png_set_compression_method) PNGARG((png_structp png_ptr,
+   int method));
+
+/* These next functions are called for input/output, memory, and error
+ * handling.  They are in the file pngrio.c, pngwio.c, and pngerror.c,
+ * and call standard C I/O routines such as fread(), fwrite(), and
+ * fprintf().  These functions can be made to use other I/O routines
+ * at run time for those applications that need to handle I/O in a
+ * different manner by calling png_set_???_fn().  See libpng.txt for
+ * more information.
+ */
+
+#if !defined(PNG_NO_STDIO)
+/* Initialize the input/output for the PNG file to the default functions. */
+extern PNG_EXPORT(void,png_init_io) PNGARG((png_structp png_ptr, png_FILE_p fp));
+#endif
+
+/* Replace the (error and abort), and warning functions with user
+ * supplied functions.  If no messages are to be printed you must still
+ * write and use replacement functions. The replacement error_fn should
+ * still do a longjmp to the last setjmp location if you are using this
+ * method of error handling.  If error_fn or warning_fn is NULL, the
+ * default function will be used.
+ */
+
+extern PNG_EXPORT(void,png_set_error_fn) PNGARG((png_structp png_ptr,
+   png_voidp error_ptr, png_error_ptr error_fn, png_error_ptr warning_fn));
+
+/* Return the user pointer associated with the error functions */
+extern PNG_EXPORT(png_voidp,png_get_error_ptr) PNGARG((png_structp png_ptr));
+
+/* Replace the default data output functions with a user supplied one(s).
+ * If buffered output is not used, then output_flush_fn can be set to NULL.
+ * If PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile time
+ * output_flush_fn will be ignored (and thus can be NULL).
+ */
+extern PNG_EXPORT(void,png_set_write_fn) PNGARG((png_structp png_ptr,
+   png_voidp io_ptr, png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn));
+
+/* Replace the default data input function with a user supplied one. */
+extern PNG_EXPORT(void,png_set_read_fn) PNGARG((png_structp png_ptr,
+   png_voidp io_ptr, png_rw_ptr read_data_fn));
+
+/* Return the user pointer associated with the I/O functions */
+extern PNG_EXPORT(png_voidp,png_get_io_ptr) PNGARG((png_structp png_ptr));
+
+extern PNG_EXPORT(void,png_set_read_status_fn) PNGARG((png_structp png_ptr,
+   png_read_status_ptr read_row_fn));
+
+extern PNG_EXPORT(void,png_set_write_status_fn) PNGARG((png_structp png_ptr,
+   png_write_status_ptr write_row_fn));
+
+#ifdef PNG_USER_MEM_SUPPORTED
+/* Replace the default memory allocation functions with user supplied one(s). */
+extern PNG_EXPORT(void,png_set_mem_fn) PNGARG((png_structp png_ptr,
+   png_voidp mem_ptr, png_malloc_ptr malloc_fn, png_free_ptr free_fn));
+/* Return the user pointer associated with the memory functions */
+extern PNG_EXPORT(png_voidp,png_get_mem_ptr) PNGARG((png_structp png_ptr));
+#endif
+
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
+    defined(PNG_LEGACY_SUPPORTED)
+extern PNG_EXPORT(void,png_set_read_user_transform_fn) PNGARG((png_structp
+   png_ptr, png_user_transform_ptr read_user_transform_fn));
+#endif
+
+#if defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) || \
+    defined(PNG_LEGACY_SUPPORTED)
+extern PNG_EXPORT(void,png_set_write_user_transform_fn) PNGARG((png_structp
+   png_ptr, png_user_transform_ptr write_user_transform_fn));
+#endif
+
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
+    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) || \
+    defined(PNG_LEGACY_SUPPORTED)
+extern PNG_EXPORT(void,png_set_user_transform_info) PNGARG((png_structp
+   png_ptr, png_voidp user_transform_ptr, int user_transform_depth,
+   int user_transform_channels));
+/* Return the user pointer associated with the user transform functions */
+extern PNG_EXPORT(png_voidp,png_get_user_transform_ptr)
+   PNGARG((png_structp png_ptr));
+#endif
+
+#ifdef PNG_USER_CHUNKS_SUPPORTED
+extern PNG_EXPORT(void,png_set_read_user_chunk_fn) PNGARG((png_structp png_ptr,
+   png_voidp user_chunk_ptr, png_user_chunk_ptr read_user_chunk_fn));
+extern PNG_EXPORT(png_voidp,png_get_user_chunk_ptr) PNGARG((png_structp
+   png_ptr));
+#endif
+
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+/* Sets the function callbacks for the push reader, and a pointer to a
+ * user-defined structure available to the callback functions.
+ */
+extern PNG_EXPORT(void,png_set_progressive_read_fn) PNGARG((png_structp png_ptr,
+   png_voidp progressive_ptr,
+   png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
+   png_progressive_end_ptr end_fn));
+
+/* returns the user pointer associated with the push read functions */
+extern PNG_EXPORT(png_voidp,png_get_progressive_ptr)
+   PNGARG((png_structp png_ptr));
+
+/* function to be called when data becomes available */
+extern PNG_EXPORT(void,png_process_data) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_bytep buffer, png_size_t buffer_size));
+
+/* function that combines rows.  Not very much different than the
+ * png_combine_row() call.  Is this even used?????
+ */
+extern PNG_EXPORT(void,png_progressive_combine_row) PNGARG((png_structp png_ptr,
+   png_bytep old_row, png_bytep new_row));
+#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
+
+extern PNG_EXPORT(png_voidp,png_malloc) PNGARG((png_structp png_ptr,
+   png_uint_32 size));
+
+#if defined(PNG_1_0_X)
+#  define png_malloc_warn png_malloc
+#else
+/* Added at libpng version 1.2.4 */
+extern PNG_EXPORT(png_voidp,png_malloc_warn) PNGARG((png_structp png_ptr,
+   png_uint_32 size));
+#endif
+
+/* frees a pointer allocated by png_malloc() */
+extern PNG_EXPORT(void,png_free) PNGARG((png_structp png_ptr, png_voidp ptr));
+
+#if defined(PNG_1_0_X)
+/* Function to allocate memory for zlib. */
+extern PNG_EXPORT(voidpf,png_zalloc) PNGARG((voidpf png_ptr, uInt items,
+   uInt size));
+
+/* Function to free memory for zlib */
+extern PNG_EXPORT(void,png_zfree) PNGARG((voidpf png_ptr, voidpf ptr));
+#endif
+
+/* Free data that was allocated internally */
+extern PNG_EXPORT(void,png_free_data) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_uint_32 free_me, int num));
+#ifdef PNG_FREE_ME_SUPPORTED
+/* Reassign responsibility for freeing existing data, whether allocated
+ * by libpng or by the application */
+extern PNG_EXPORT(void,png_data_freer) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, int freer, png_uint_32 mask));
+#endif
+/* assignments for png_data_freer */
+#define PNG_DESTROY_WILL_FREE_DATA 1
+#define PNG_SET_WILL_FREE_DATA 1
+#define PNG_USER_WILL_FREE_DATA 2
+/* Flags for png_ptr->free_me and info_ptr->free_me */
+#define PNG_FREE_HIST 0x0008
+#define PNG_FREE_ICCP 0x0010
+#define PNG_FREE_SPLT 0x0020
+#define PNG_FREE_ROWS 0x0040
+#define PNG_FREE_PCAL 0x0080
+#define PNG_FREE_SCAL 0x0100
+#define PNG_FREE_UNKN 0x0200
+#define PNG_FREE_LIST 0x0400
+#define PNG_FREE_PLTE 0x1000
+#define PNG_FREE_TRNS 0x2000
+#define PNG_FREE_TEXT 0x4000
+#define PNG_FREE_ALL  0x7fff
+#define PNG_FREE_MUL  0x4220 /* PNG_FREE_SPLT|PNG_FREE_TEXT|PNG_FREE_UNKN */
+
+#ifdef PNG_USER_MEM_SUPPORTED
+extern PNG_EXPORT(png_voidp,png_malloc_default) PNGARG((png_structp png_ptr,
+   png_uint_32 size));
+extern PNG_EXPORT(void,png_free_default) PNGARG((png_structp png_ptr,
+   png_voidp ptr));
+#endif
+
+extern PNG_EXPORT(png_voidp,png_memcpy_check) PNGARG((png_structp png_ptr,
+   png_voidp s1, png_voidp s2, png_uint_32 size));
+
+extern PNG_EXPORT(png_voidp,png_memset_check) PNGARG((png_structp png_ptr,
+   png_voidp s1, int value, png_uint_32 size));
+
+#if defined(USE_FAR_KEYWORD)  /* memory model conversion function */
+extern void *png_far_to_near PNGARG((png_structp png_ptr,png_voidp ptr,
+   int check));
+#endif /* USE_FAR_KEYWORD */
+
+/* Fatal error in PNG image of libpng - can't continue */
+extern PNG_EXPORT(void,png_error) PNGARG((png_structp png_ptr,
+   png_const_charp error_message));
+
+/* The same, but the chunk name is prepended to the error string. */
+extern PNG_EXPORT(void,png_chunk_error) PNGARG((png_structp png_ptr,
+   png_const_charp error_message));
+
+#ifndef PNG_NO_WARNINGS
+/* Non-fatal error in libpng.  Can continue, but may have a problem. */
+extern PNG_EXPORT(void,png_warning) PNGARG((png_structp png_ptr,
+   png_const_charp warning_message));
+
+#ifdef PNG_READ_SUPPORTED
+/* Non-fatal error in libpng, chunk name is prepended to message. */
+extern PNG_EXPORT(void,png_chunk_warning) PNGARG((png_structp png_ptr,
+   png_const_charp warning_message));
+#endif /* PNG_READ_SUPPORTED */
+#endif /* PNG_NO_WARNINGS */
+
+/* The png_set_<chunk> functions are for storing values in the png_info_struct.
+ * Similarly, the png_get_<chunk> calls are used to read values from the
+ * png_info_struct, either storing the parameters in the passed variables, or
+ * setting pointers into the png_info_struct where the data is stored.  The
+ * png_get_<chunk> functions return a non-zero value if the data was available
+ * in info_ptr, or return zero and do not change any of the parameters if the
+ * data was not available.
+ *
+ * These functions should be used instead of directly accessing png_info
+ * to avoid problems with future changes in the size and internal layout of
+ * png_info_struct.
+ */
+/* Returns "flag" if chunk data is valid in info_ptr. */
+extern PNG_EXPORT(png_uint_32,png_get_valid) PNGARG((png_structp png_ptr,
+png_infop info_ptr, png_uint_32 flag));
+
+/* Returns number of bytes needed to hold a transformed row. */
+extern PNG_EXPORT(png_uint_32,png_get_rowbytes) PNGARG((png_structp png_ptr,
+png_infop info_ptr));
+
+#if defined(PNG_INFO_IMAGE_SUPPORTED)
+/* Returns row_pointers, which is an array of pointers to scanlines that was
+returned from png_read_png(). */
+extern PNG_EXPORT(png_bytepp,png_get_rows) PNGARG((png_structp png_ptr,
+png_infop info_ptr));
+/* Set row_pointers, which is an array of pointers to scanlines for use
+by png_write_png(). */
+extern PNG_EXPORT(void,png_set_rows) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_bytepp row_pointers));
+#endif
+
+/* Returns number of color channels in image. */
+extern PNG_EXPORT(png_byte,png_get_channels) PNGARG((png_structp png_ptr,
+png_infop info_ptr));
+
+#ifdef PNG_EASY_ACCESS_SUPPORTED
+/* Returns image width in pixels. */
+extern PNG_EXPORT(png_uint_32, png_get_image_width) PNGARG((png_structp
+png_ptr, png_infop info_ptr));
+
+/* Returns image height in pixels. */
+extern PNG_EXPORT(png_uint_32, png_get_image_height) PNGARG((png_structp
+png_ptr, png_infop info_ptr));
+
+/* Returns image bit_depth. */
+extern PNG_EXPORT(png_byte, png_get_bit_depth) PNGARG((png_structp
+png_ptr, png_infop info_ptr));
+
+/* Returns image color_type. */
+extern PNG_EXPORT(png_byte, png_get_color_type) PNGARG((png_structp
+png_ptr, png_infop info_ptr));
+
+/* Returns image filter_type. */
+extern PNG_EXPORT(png_byte, png_get_filter_type) PNGARG((png_structp
+png_ptr, png_infop info_ptr));
+
+/* Returns image interlace_type. */
+extern PNG_EXPORT(png_byte, png_get_interlace_type) PNGARG((png_structp
+png_ptr, png_infop info_ptr));
+
+/* Returns image compression_type. */
+extern PNG_EXPORT(png_byte, png_get_compression_type) PNGARG((png_structp
+png_ptr, png_infop info_ptr));
+
+/* Returns image resolution in pixels per meter, from pHYs chunk data. */
+extern PNG_EXPORT(png_uint_32, png_get_pixels_per_meter) PNGARG((png_structp
+png_ptr, png_infop info_ptr));
+extern PNG_EXPORT(png_uint_32, png_get_x_pixels_per_meter) PNGARG((png_structp
+png_ptr, png_infop info_ptr));
+extern PNG_EXPORT(png_uint_32, png_get_y_pixels_per_meter) PNGARG((png_structp
+png_ptr, png_infop info_ptr));
+
+/* Returns pixel aspect ratio, computed from pHYs chunk data.  */
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+extern PNG_EXPORT(float, png_get_pixel_aspect_ratio) PNGARG((png_structp
+png_ptr, png_infop info_ptr));
+#endif
+
+/* Returns image x, y offset in pixels or microns, from oFFs chunk data. */
+extern PNG_EXPORT(png_int_32, png_get_x_offset_pixels) PNGARG((png_structp
+png_ptr, png_infop info_ptr));
+extern PNG_EXPORT(png_int_32, png_get_y_offset_pixels) PNGARG((png_structp
+png_ptr, png_infop info_ptr));
+extern PNG_EXPORT(png_int_32, png_get_x_offset_microns) PNGARG((png_structp
+png_ptr, png_infop info_ptr));
+extern PNG_EXPORT(png_int_32, png_get_y_offset_microns) PNGARG((png_structp
+png_ptr, png_infop info_ptr));
+
+#endif /* PNG_EASY_ACCESS_SUPPORTED */
+
+/* Returns pointer to signature string read from PNG header */
+extern PNG_EXPORT(png_bytep,png_get_signature) PNGARG((png_structp png_ptr,
+png_infop info_ptr));
+
+#if defined(PNG_bKGD_SUPPORTED)
+extern PNG_EXPORT(png_uint_32,png_get_bKGD) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_color_16p *background));
+#endif
+
+#if defined(PNG_bKGD_SUPPORTED)
+extern PNG_EXPORT(void,png_set_bKGD) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_color_16p background));
+#endif
+
+#if defined(PNG_cHRM_SUPPORTED)
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+extern PNG_EXPORT(png_uint_32,png_get_cHRM) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, double *white_x, double *white_y, double *red_x,
+   double *red_y, double *green_x, double *green_y, double *blue_x,
+   double *blue_y));
+#endif
+#ifdef PNG_FIXED_POINT_SUPPORTED
+extern PNG_EXPORT(png_uint_32,png_get_cHRM_fixed) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_fixed_point *int_white_x, png_fixed_point
+   *int_white_y, png_fixed_point *int_red_x, png_fixed_point *int_red_y,
+   png_fixed_point *int_green_x, png_fixed_point *int_green_y, png_fixed_point
+   *int_blue_x, png_fixed_point *int_blue_y));
+#endif
+#endif
+
+#if defined(PNG_cHRM_SUPPORTED)
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+extern PNG_EXPORT(void,png_set_cHRM) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, double white_x, double white_y, double red_x,
+   double red_y, double green_x, double green_y, double blue_x, double blue_y));
+#endif
+#ifdef PNG_FIXED_POINT_SUPPORTED
+extern PNG_EXPORT(void,png_set_cHRM_fixed) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_fixed_point int_white_x, png_fixed_point int_white_y,
+   png_fixed_point int_red_x, png_fixed_point int_red_y, png_fixed_point
+   int_green_x, png_fixed_point int_green_y, png_fixed_point int_blue_x,
+   png_fixed_point int_blue_y));
+#endif
+#endif
+
+#if defined(PNG_gAMA_SUPPORTED)
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+extern PNG_EXPORT(png_uint_32,png_get_gAMA) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, double *file_gamma));
+#endif
+extern PNG_EXPORT(png_uint_32,png_get_gAMA_fixed) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_fixed_point *int_file_gamma));
+#endif
+
+#if defined(PNG_gAMA_SUPPORTED)
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+extern PNG_EXPORT(void,png_set_gAMA) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, double file_gamma));
+#endif
+extern PNG_EXPORT(void,png_set_gAMA_fixed) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_fixed_point int_file_gamma));
+#endif
+
+#if defined(PNG_hIST_SUPPORTED)
+extern PNG_EXPORT(png_uint_32,png_get_hIST) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_uint_16p *hist));
+#endif
+
+#if defined(PNG_hIST_SUPPORTED)
+extern PNG_EXPORT(void,png_set_hIST) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_uint_16p hist));
+#endif
+
+extern PNG_EXPORT(png_uint_32,png_get_IHDR) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_uint_32 *width, png_uint_32 *height,
+   int *bit_depth, int *color_type, int *interlace_method,
+   int *compression_method, int *filter_method));
+
+extern PNG_EXPORT(void,png_set_IHDR) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_uint_32 width, png_uint_32 height, int bit_depth,
+   int color_type, int interlace_method, int compression_method,
+   int filter_method));
+
+#if defined(PNG_oFFs_SUPPORTED)
+extern PNG_EXPORT(png_uint_32,png_get_oFFs) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_int_32 *offset_x, png_int_32 *offset_y,
+   int *unit_type));
+#endif
+
+#if defined(PNG_oFFs_SUPPORTED)
+extern PNG_EXPORT(void,png_set_oFFs) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_int_32 offset_x, png_int_32 offset_y,
+   int unit_type));
+#endif
+
+#if defined(PNG_pCAL_SUPPORTED)
+extern PNG_EXPORT(png_uint_32,png_get_pCAL) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_charp *purpose, png_int_32 *X0, png_int_32 *X1,
+   int *type, int *nparams, png_charp *units, png_charpp *params));
+#endif
+
+#if defined(PNG_pCAL_SUPPORTED)
+extern PNG_EXPORT(void,png_set_pCAL) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_charp purpose, png_int_32 X0, png_int_32 X1,
+   int type, int nparams, png_charp units, png_charpp params));
+#endif
+
+#if defined(PNG_pHYs_SUPPORTED)
+extern PNG_EXPORT(png_uint_32,png_get_pHYs) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_uint_32 *res_x, png_uint_32 *res_y, int *unit_type));
+#endif
+
+#if defined(PNG_pHYs_SUPPORTED)
+extern PNG_EXPORT(void,png_set_pHYs) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_uint_32 res_x, png_uint_32 res_y, int unit_type));
+#endif
+
+extern PNG_EXPORT(png_uint_32,png_get_PLTE) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_colorp *palette, int *num_palette));
+
+extern PNG_EXPORT(void,png_set_PLTE) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_colorp palette, int num_palette));
+
+#if defined(PNG_sBIT_SUPPORTED)
+extern PNG_EXPORT(png_uint_32,png_get_sBIT) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_color_8p *sig_bit));
+#endif
+
+#if defined(PNG_sBIT_SUPPORTED)
+extern PNG_EXPORT(void,png_set_sBIT) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_color_8p sig_bit));
+#endif
+
+#if defined(PNG_sRGB_SUPPORTED)
+extern PNG_EXPORT(png_uint_32,png_get_sRGB) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, int *intent));
+#endif
+
+#if defined(PNG_sRGB_SUPPORTED)
+extern PNG_EXPORT(void,png_set_sRGB) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, int intent));
+extern PNG_EXPORT(void,png_set_sRGB_gAMA_and_cHRM) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, int intent));
+#endif
+
+#if defined(PNG_iCCP_SUPPORTED)
+extern PNG_EXPORT(png_uint_32,png_get_iCCP) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_charpp name, int *compression_type,
+   png_charpp profile, png_uint_32 *proflen));
+   /* Note to maintainer: profile should be png_bytepp */
+#endif
+
+#if defined(PNG_iCCP_SUPPORTED)
+extern PNG_EXPORT(void,png_set_iCCP) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_charp name, int compression_type,
+   png_charp profile, png_uint_32 proflen));
+   /* Note to maintainer: profile should be png_bytep */
+#endif
+
+#if defined(PNG_sPLT_SUPPORTED)
+extern PNG_EXPORT(png_uint_32,png_get_sPLT) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_sPLT_tpp entries));
+#endif
+
+#if defined(PNG_sPLT_SUPPORTED)
+extern PNG_EXPORT(void,png_set_sPLT) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_sPLT_tp entries, int nentries));
+#endif
+
+#if defined(PNG_TEXT_SUPPORTED)
+/* png_get_text also returns the number of text chunks in *num_text */
+extern PNG_EXPORT(png_uint_32,png_get_text) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_textp *text_ptr, int *num_text));
+#endif
+
+/*
+ *  Note while png_set_text() will accept a structure whose text,
+ *  language, and  translated keywords are NULL pointers, the structure
+ *  returned by png_get_text will always contain regular
+ *  zero-terminated C strings.  They might be empty strings but
+ *  they will never be NULL pointers.
+ */
+
+#if defined(PNG_TEXT_SUPPORTED)
+extern PNG_EXPORT(void,png_set_text) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_textp text_ptr, int num_text));
+#endif
+
+#if defined(PNG_tIME_SUPPORTED)
+extern PNG_EXPORT(png_uint_32,png_get_tIME) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_timep *mod_time));
+#endif
+
+#if defined(PNG_tIME_SUPPORTED)
+extern PNG_EXPORT(void,png_set_tIME) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_timep mod_time));
+#endif
+
+#if defined(PNG_tRNS_SUPPORTED)
+extern PNG_EXPORT(png_uint_32,png_get_tRNS) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_bytep *trans, int *num_trans,
+   png_color_16p *trans_values));
+#endif
+
+#if defined(PNG_tRNS_SUPPORTED)
+extern PNG_EXPORT(void,png_set_tRNS) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_bytep trans, int num_trans,
+   png_color_16p trans_values));
+#endif
+
+#if defined(PNG_tRNS_SUPPORTED)
+#endif
+
+#if defined(PNG_sCAL_SUPPORTED)
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+extern PNG_EXPORT(png_uint_32,png_get_sCAL) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, int *unit, double *width, double *height));
+#else
+#ifdef PNG_FIXED_POINT_SUPPORTED
+extern PNG_EXPORT(png_uint_32,png_get_sCAL_s) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, int *unit, png_charpp swidth, png_charpp sheight));
+#endif
+#endif
+#endif /* PNG_sCAL_SUPPORTED */
+
+#if defined(PNG_sCAL_SUPPORTED)
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+extern PNG_EXPORT(void,png_set_sCAL) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, int unit, double width, double height));
+#else
+#ifdef PNG_FIXED_POINT_SUPPORTED
+extern PNG_EXPORT(void,png_set_sCAL_s) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, int unit, png_charp swidth, png_charp sheight));
+#endif
+#endif
+#endif /* PNG_sCAL_SUPPORTED || PNG_WRITE_sCAL_SUPPORTED */
+
+#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+/* provide a list of chunks and how they are to be handled, if the built-in
+   handling or default unknown chunk handling is not desired.  Any chunks not
+   listed will be handled in the default manner.  The IHDR and IEND chunks
+   must not be listed.
+      keep = 0: follow default behaviour
+           = 1: do not keep
+           = 2: keep only if safe-to-copy
+           = 3: keep even if unsafe-to-copy
+*/
+extern PNG_EXPORT(void, png_set_keep_unknown_chunks) PNGARG((png_structp
+   png_ptr, int keep, png_bytep chunk_list, int num_chunks));
+extern PNG_EXPORT(void, png_set_unknown_chunks) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_unknown_chunkp unknowns, int num_unknowns));
+extern PNG_EXPORT(void, png_set_unknown_chunk_location)
+   PNGARG((png_structp png_ptr, png_infop info_ptr, int chunk, int location));
+extern PNG_EXPORT(png_uint_32,png_get_unknown_chunks) PNGARG((png_structp
+   png_ptr, png_infop info_ptr, png_unknown_chunkpp entries));
+#endif
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+PNG_EXPORT(int,png_handle_as_unknown) PNGARG((png_structp png_ptr, png_bytep
+   chunk_name));
+#endif
+
+/* Png_free_data() will turn off the "valid" flag for anything it frees.
+   If you need to turn it off for a chunk that your application has freed,
+   you can use png_set_invalid(png_ptr, info_ptr, PNG_INFO_CHNK); */
+extern PNG_EXPORT(void, png_set_invalid) PNGARG((png_structp png_ptr,
+   png_infop info_ptr, int mask));
+
+#if defined(PNG_INFO_IMAGE_SUPPORTED)
+/* The "params" pointer is currently not used and is for future expansion. */
+extern PNG_EXPORT(void, png_read_png) PNGARG((png_structp png_ptr,
+                        png_infop info_ptr,
+                        int transforms,
+                        png_voidp params));
+extern PNG_EXPORT(void, png_write_png) PNGARG((png_structp png_ptr,
+                        png_infop info_ptr,
+                        int transforms,
+                        png_voidp params));
+#endif
+
+/* Define PNG_DEBUG at compile time for debugging information.  Higher
+ * numbers for PNG_DEBUG mean more debugging information.  This has
+ * only been added since version 0.95 so it is not implemented throughout
+ * libpng yet, but more support will be added as needed.
+ */
+#ifdef PNG_DEBUG
+#if (PNG_DEBUG > 0)
+#if !defined(PNG_DEBUG_FILE) && defined(_MSC_VER)
+#include <crtdbg.h>
+#if (PNG_DEBUG > 1)
+#define png_debug(l,m)  _RPT0(_CRT_WARN,m)
+#define png_debug1(l,m,p1)  _RPT1(_CRT_WARN,m,p1)
+#define png_debug2(l,m,p1,p2) _RPT2(_CRT_WARN,m,p1,p2)
+#endif
+#else /* PNG_DEBUG_FILE || !_MSC_VER */
+#ifndef PNG_DEBUG_FILE
+#define PNG_DEBUG_FILE stderr
+#endif /* PNG_DEBUG_FILE */
+#if (PNG_DEBUG > 1)
+#define png_debug(l,m) \
+{ \
+     int num_tabs=l; \
+     fprintf(PNG_DEBUG_FILE,"%s"m,(num_tabs==1 ? "\t" : \
+       (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":"")))); \
+}
+#define png_debug1(l,m,p1) \
+{ \
+     int num_tabs=l; \
+     fprintf(PNG_DEBUG_FILE,"%s"m,(num_tabs==1 ? "\t" : \
+       (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))),p1); \
+}
+#define png_debug2(l,m,p1,p2) \
+{ \
+     int num_tabs=l; \
+     fprintf(PNG_DEBUG_FILE,"%s"m,(num_tabs==1 ? "\t" : \
+       (num_tabs==2 ? "\t\t":(num_tabs>2 ? "\t\t\t":""))),p1,p2); \
+}
+#endif /* (PNG_DEBUG > 1) */
+#endif /* _MSC_VER */
+#endif /* (PNG_DEBUG > 0) */
+#endif /* PNG_DEBUG */
+#ifndef png_debug
+#define png_debug(l, m)
+#endif
+#ifndef png_debug1
+#define png_debug1(l, m, p1)
+#endif
+#ifndef png_debug2
+#define png_debug2(l, m, p1, p2)
+#endif
+
+extern PNG_EXPORT(png_charp,png_get_copyright) PNGARG((png_structp png_ptr));
+extern PNG_EXPORT(png_charp,png_get_header_ver) PNGARG((png_structp png_ptr));
+extern PNG_EXPORT(png_charp,png_get_header_version) PNGARG((png_structp png_ptr));
+extern PNG_EXPORT(png_charp,png_get_libpng_ver) PNGARG((png_structp png_ptr));
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+extern PNG_EXPORT(png_uint_32,png_permit_mng_features) PNGARG((png_structp
+   png_ptr, png_uint_32 mng_features_permitted));
+#endif
+
+/* For use in png_set_keep_unknown, added to version 1.2.6 */
+#define PNG_HANDLE_CHUNK_AS_DEFAULT   0
+#define PNG_HANDLE_CHUNK_NEVER        1
+#define PNG_HANDLE_CHUNK_IF_SAFE      2
+#define PNG_HANDLE_CHUNK_ALWAYS       3
+
+/* Added to version 1.2.0 */
+#if defined(PNG_ASSEMBLER_CODE_SUPPORTED)
+#if defined(PNG_MMX_CODE_SUPPORTED)
+#define PNG_ASM_FLAG_MMX_SUPPORT_COMPILED  0x01  /* not user-settable */
+#define PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU    0x02  /* not user-settable */
+#define PNG_ASM_FLAG_MMX_READ_COMBINE_ROW  0x04
+#define PNG_ASM_FLAG_MMX_READ_INTERLACE    0x08
+#define PNG_ASM_FLAG_MMX_READ_FILTER_SUB   0x10
+#define PNG_ASM_FLAG_MMX_READ_FILTER_UP    0x20
+#define PNG_ASM_FLAG_MMX_READ_FILTER_AVG   0x40
+#define PNG_ASM_FLAG_MMX_READ_FILTER_PAETH 0x80
+#define PNG_ASM_FLAGS_INITIALIZED          0x80000000  /* not user-settable */
+
+#define PNG_MMX_READ_FLAGS ( PNG_ASM_FLAG_MMX_READ_COMBINE_ROW  \
+                           | PNG_ASM_FLAG_MMX_READ_INTERLACE    \
+                           | PNG_ASM_FLAG_MMX_READ_FILTER_SUB   \
+                           | PNG_ASM_FLAG_MMX_READ_FILTER_UP    \
+                           | PNG_ASM_FLAG_MMX_READ_FILTER_AVG   \
+                           | PNG_ASM_FLAG_MMX_READ_FILTER_PAETH )
+#define PNG_MMX_WRITE_FLAGS ( 0 )
+
+#define PNG_MMX_FLAGS ( PNG_ASM_FLAG_MMX_SUPPORT_COMPILED \
+                      | PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU   \
+                      | PNG_MMX_READ_FLAGS                \
+                      | PNG_MMX_WRITE_FLAGS )
+
+#define PNG_SELECT_READ   1
+#define PNG_SELECT_WRITE  2
+#endif /* PNG_MMX_CODE_SUPPORTED */
+
+#if !defined(PNG_1_0_X)
+/* pngget.c */
+extern PNG_EXPORT(png_uint_32,png_get_mmx_flagmask)
+   PNGARG((int flag_select, int *compilerID));
+
+/* pngget.c */
+extern PNG_EXPORT(png_uint_32,png_get_asm_flagmask)
+   PNGARG((int flag_select));
+
+/* pngget.c */
+extern PNG_EXPORT(png_uint_32,png_get_asm_flags)
+   PNGARG((png_structp png_ptr));
+
+/* pngget.c */
+extern PNG_EXPORT(png_byte,png_get_mmx_bitdepth_threshold)
+   PNGARG((png_structp png_ptr));
+
+/* pngget.c */
+extern PNG_EXPORT(png_uint_32,png_get_mmx_rowbytes_threshold)
+   PNGARG((png_structp png_ptr));
+
+/* pngset.c */
+extern PNG_EXPORT(void,png_set_asm_flags)
+   PNGARG((png_structp png_ptr, png_uint_32 asm_flags));
+
+/* pngset.c */
+extern PNG_EXPORT(void,png_set_mmx_thresholds)
+   PNGARG((png_structp png_ptr, png_byte mmx_bitdepth_threshold,
+   png_uint_32 mmx_rowbytes_threshold));
+
+#endif /* PNG_1_0_X */
+
+#if !defined(PNG_1_0_X)
+/* png.c, pnggccrd.c, or pngvcrd.c */
+extern PNG_EXPORT(int,png_mmx_support) PNGARG((void));
+#endif /* PNG_ASSEMBLER_CODE_SUPPORTED */
+
+/* Strip the prepended error numbers ("#nnn ") from error and warning
+ * messages before passing them to the error or warning handler. */
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+extern PNG_EXPORT(void,png_set_strip_error_numbers) PNGARG((png_structp
+   png_ptr, png_uint_32 strip_mode));
+#endif
+
+#endif /* PNG_1_0_X */
+
+/* Added at libpng-1.2.6 */
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+extern PNG_EXPORT(void,png_set_user_limits) PNGARG((png_structp
+   png_ptr, png_uint_32 user_width_max, png_uint_32 user_height_max));
+extern PNG_EXPORT(png_uint_32,png_get_user_width_max) PNGARG((png_structp
+   png_ptr));
+extern PNG_EXPORT(png_uint_32,png_get_user_height_max) PNGARG((png_structp
+   png_ptr));
+#endif
+
+/* Maintainer: Put new public prototypes here ^, in libpng.3, and project defs */
+
+#ifdef PNG_READ_COMPOSITE_NODIV_SUPPORTED
+/* With these routines we avoid an integer divide, which will be slower on
+ * most machines.  However, it does take more operations than the corresponding
+ * divide method, so it may be slower on a few RISC systems.  There are two
+ * shifts (by 8 or 16 bits) and an addition, versus a single integer divide.
+ *
+ * Note that the rounding factors are NOT supposed to be the same!  128 and
+ * 32768 are correct for the NODIV code; 127 and 32767 are correct for the
+ * standard method.
+ *
+ * [Optimized code by Greg Roelofs and Mark Adler...blame us for bugs. :-) ]
+ */
+
+ /* fg and bg should be in `gamma 1.0' space; alpha is the opacity          */
+
+#  define png_composite(composite, fg, alpha, bg)                            \
+     { png_uint_16 temp = (png_uint_16)((png_uint_16)(fg) * (png_uint_16)(alpha) \
+                        +        (png_uint_16)(bg)*(png_uint_16)(255 -       \
+                        (png_uint_16)(alpha)) + (png_uint_16)128);           \
+       (composite) = (png_byte)((temp + (temp >> 8)) >> 8); }
+
+#  define png_composite_16(composite, fg, alpha, bg)                         \
+     { png_uint_32 temp = (png_uint_32)((png_uint_32)(fg) * (png_uint_32)(alpha) \
+                        + (png_uint_32)(bg)*(png_uint_32)(65535L -           \
+                        (png_uint_32)(alpha)) + (png_uint_32)32768L);        \
+       (composite) = (png_uint_16)((temp + (temp >> 16)) >> 16); }
+
+#else  /* standard method using integer division */
+
+#  define png_composite(composite, fg, alpha, bg)                            \
+     (composite) = (png_byte)(((png_uint_16)(fg) * (png_uint_16)(alpha) +    \
+       (png_uint_16)(bg) * (png_uint_16)(255 - (png_uint_16)(alpha)) +       \
+       (png_uint_16)127) / 255)
+
+#  define png_composite_16(composite, fg, alpha, bg)                         \
+     (composite) = (png_uint_16)(((png_uint_32)(fg) * (png_uint_32)(alpha) + \
+       (png_uint_32)(bg)*(png_uint_32)(65535L - (png_uint_32)(alpha)) +      \
+       (png_uint_32)32767) / (png_uint_32)65535L)
+
+#endif /* PNG_READ_COMPOSITE_NODIV_SUPPORTED */
+
+/* Inline macros to do direct reads of bytes from the input buffer.  These
+ * require that you are using an architecture that uses PNG byte ordering
+ * (MSB first) and supports unaligned data storage.  I think that PowerPC
+ * in big-endian mode and 680x0 are the only ones that will support this.
+ * The x86 line of processors definitely do not.  The png_get_int_32()
+ * routine also assumes we are using two's complement format for negative
+ * values, which is almost certainly true.
+ */
+#if defined(PNG_READ_BIG_ENDIAN_SUPPORTED)
+#  define png_get_uint_32(buf) ( *((png_uint_32p) (buf)))
+#  define png_get_uint_16(buf) ( *((png_uint_16p) (buf)))
+#  define png_get_int_32(buf)  ( *((png_int_32p)  (buf)))
+#else
+extern PNG_EXPORT(png_uint_32,png_get_uint_32) PNGARG((png_bytep buf));
+extern PNG_EXPORT(png_uint_16,png_get_uint_16) PNGARG((png_bytep buf));
+extern PNG_EXPORT(png_int_32,png_get_int_32) PNGARG((png_bytep buf));
+#endif /* !PNG_READ_BIG_ENDIAN_SUPPORTED */
+extern PNG_EXPORT(png_uint_32,png_get_uint_31)
+  PNGARG((png_structp png_ptr, png_bytep buf));
+/* No png_get_int_16 -- may be added if there's a real need for it. */
+
+/* Place a 32-bit number into a buffer in PNG byte order (big-endian).
+ */
+extern PNG_EXPORT(void,png_save_uint_32)
+   PNGARG((png_bytep buf, png_uint_32 i));
+extern PNG_EXPORT(void,png_save_int_32)
+   PNGARG((png_bytep buf, png_int_32 i));
+
+/* Place a 16-bit number into a buffer in PNG byte order.
+ * The parameter is declared unsigned int, not png_uint_16,
+ * just to avoid potential problems on pre-ANSI C compilers.
+ */
+extern PNG_EXPORT(void,png_save_uint_16)
+   PNGARG((png_bytep buf, unsigned int i));
+/* No png_save_int_16 -- may be added if there's a real need for it. */
+
+/* ************************************************************************* */
+
+/* These next functions are used internally in the code.  They generally
+ * shouldn't be used unless you are writing code to add or replace some
+ * functionality in libpng.  More information about most functions can
+ * be found in the files where the functions are located.
+ */
+
+
+/* Various modes of operation, that are visible to applications because
+ * they are used for unknown chunk location.
+ */
+#define PNG_HAVE_IHDR               0x01
+#define PNG_HAVE_PLTE               0x02
+#define PNG_HAVE_IDAT               0x04
+#define PNG_AFTER_IDAT              0x08 /* Have complete zlib datastream */
+#define PNG_HAVE_IEND               0x10
+
+#if defined(PNG_INTERNAL)
+
+/* More modes of operation.  Note that after an init, mode is set to
+ * zero automatically when the structure is created.
+ */
+#define PNG_HAVE_gAMA               0x20
+#define PNG_HAVE_cHRM               0x40
+#define PNG_HAVE_sRGB               0x80
+#define PNG_HAVE_CHUNK_HEADER      0x100
+#define PNG_WROTE_tIME             0x200
+#define PNG_WROTE_INFO_BEFORE_PLTE 0x400
+#define PNG_BACKGROUND_IS_GRAY     0x800
+#define PNG_HAVE_PNG_SIGNATURE    0x1000
+#define PNG_HAVE_CHUNK_AFTER_IDAT 0x2000 /* Have another chunk after IDAT */
+
+/* flags for the transformations the PNG library does on the image data */
+#define PNG_BGR                0x0001
+#define PNG_INTERLACE          0x0002
+#define PNG_PACK               0x0004
+#define PNG_SHIFT              0x0008
+#define PNG_SWAP_BYTES         0x0010
+#define PNG_INVERT_MONO        0x0020
+#define PNG_DITHER             0x0040
+#define PNG_BACKGROUND         0x0080
+#define PNG_BACKGROUND_EXPAND  0x0100
+                          /*   0x0200 unused */
+#define PNG_16_TO_8            0x0400
+#define PNG_RGBA               0x0800
+#define PNG_EXPAND             0x1000
+#define PNG_GAMMA              0x2000
+#define PNG_GRAY_TO_RGB        0x4000
+#define PNG_FILLER             0x8000L
+#define PNG_PACKSWAP          0x10000L
+#define PNG_SWAP_ALPHA        0x20000L
+#define PNG_STRIP_ALPHA       0x40000L
+#define PNG_INVERT_ALPHA      0x80000L
+#define PNG_USER_TRANSFORM   0x100000L
+#define PNG_RGB_TO_GRAY_ERR  0x200000L
+#define PNG_RGB_TO_GRAY_WARN 0x400000L
+#define PNG_RGB_TO_GRAY      0x600000L  /* two bits, RGB_TO_GRAY_ERR|WARN */
+                       /*    0x800000L     Unused */
+#define PNG_ADD_ALPHA       0x1000000L  /* Added to libpng-1.2.7 */
+#define PNG_EXPAND_tRNS     0x2000000L  /* Added to libpng-1.2.9 */
+                       /*   0x4000000L  unused */
+                       /*   0x8000000L  unused */
+                       /*  0x10000000L  unused */
+                       /*  0x20000000L  unused */
+                       /*  0x40000000L  unused */
+
+/* flags for png_create_struct */
+#define PNG_STRUCT_PNG   0x0001
+#define PNG_STRUCT_INFO  0x0002
+
+/* Scaling factor for filter heuristic weighting calculations */
+#define PNG_WEIGHT_SHIFT 8
+#define PNG_WEIGHT_FACTOR (1<<(PNG_WEIGHT_SHIFT))
+#define PNG_COST_SHIFT 3
+#define PNG_COST_FACTOR (1<<(PNG_COST_SHIFT))
+
+/* flags for the png_ptr->flags rather than declaring a byte for each one */
+#define PNG_FLAG_ZLIB_CUSTOM_STRATEGY     0x0001
+#define PNG_FLAG_ZLIB_CUSTOM_LEVEL        0x0002
+#define PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL    0x0004
+#define PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS  0x0008
+#define PNG_FLAG_ZLIB_CUSTOM_METHOD       0x0010
+#define PNG_FLAG_ZLIB_FINISHED            0x0020
+#define PNG_FLAG_ROW_INIT                 0x0040
+#define PNG_FLAG_FILLER_AFTER             0x0080
+#define PNG_FLAG_CRC_ANCILLARY_USE        0x0100
+#define PNG_FLAG_CRC_ANCILLARY_NOWARN     0x0200
+#define PNG_FLAG_CRC_CRITICAL_USE         0x0400
+#define PNG_FLAG_CRC_CRITICAL_IGNORE      0x0800
+#define PNG_FLAG_FREE_PLTE                0x1000
+#define PNG_FLAG_FREE_TRNS                0x2000
+#define PNG_FLAG_FREE_HIST                0x4000
+#define PNG_FLAG_KEEP_UNKNOWN_CHUNKS      0x8000L
+#define PNG_FLAG_KEEP_UNSAFE_CHUNKS       0x10000L
+#define PNG_FLAG_LIBRARY_MISMATCH         0x20000L
+#define PNG_FLAG_STRIP_ERROR_NUMBERS      0x40000L
+#define PNG_FLAG_STRIP_ERROR_TEXT         0x80000L
+#define PNG_FLAG_MALLOC_NULL_MEM_OK       0x100000L
+#define PNG_FLAG_ADD_ALPHA                0x200000L  /* Added to libpng-1.2.8 */
+#define PNG_FLAG_STRIP_ALPHA              0x400000L  /* Added to libpng-1.2.8 */
+                                  /*      0x800000L  unused */
+                                  /*     0x1000000L  unused */
+                                  /*     0x2000000L  unused */
+                                  /*     0x4000000L  unused */
+                                  /*     0x8000000L  unused */
+                                  /*    0x10000000L  unused */
+                                  /*    0x20000000L  unused */
+                                  /*    0x40000000L  unused */
+
+#define PNG_FLAG_CRC_ANCILLARY_MASK (PNG_FLAG_CRC_ANCILLARY_USE | \
+                                     PNG_FLAG_CRC_ANCILLARY_NOWARN)
+
+#define PNG_FLAG_CRC_CRITICAL_MASK  (PNG_FLAG_CRC_CRITICAL_USE | \
+                                     PNG_FLAG_CRC_CRITICAL_IGNORE)
+
+#define PNG_FLAG_CRC_MASK           (PNG_FLAG_CRC_ANCILLARY_MASK | \
+                                     PNG_FLAG_CRC_CRITICAL_MASK)
+
+/* save typing and make code easier to understand */
+
+#define PNG_COLOR_DIST(c1, c2) (abs((int)((c1).red) - (int)((c2).red)) + \
+   abs((int)((c1).green) - (int)((c2).green)) + \
+   abs((int)((c1).blue) - (int)((c2).blue)))
+
+/* Added to libpng-1.2.6 JB */
+#define PNG_ROWBYTES(pixel_bits, width) \
+    ((pixel_bits) >= 8 ? \
+    ((width) * (((png_uint_32)(pixel_bits)) >> 3)) : \
+    (( ((width) * ((png_uint_32)(pixel_bits))) + 7) >> 3) )
+
+/* PNG_OUT_OF_RANGE returns true if value is outside the range
+   ideal-delta..ideal+delta.  Each argument is evaluated twice.
+   "ideal" and "delta" should be constants, normally simple
+   integers, "value" a variable. Added to libpng-1.2.6 JB */
+#define PNG_OUT_OF_RANGE(value, ideal, delta) \
+        ( (value) < (ideal)-(delta) || (value) > (ideal)+(delta) )
+
+/* variables declared in png.c - only it needs to define PNG_NO_EXTERN */
+#if !defined(PNG_NO_EXTERN) || defined(PNG_ALWAYS_EXTERN)
+/* place to hold the signature string for a PNG file. */
+#ifdef PNG_USE_GLOBAL_ARRAYS
+   PNG_EXPORT_VAR (PNG_CONST png_byte FARDATA) png_sig[8];
+#else
+#endif
+#endif /* PNG_NO_EXTERN */
+
+/* Constant strings for known chunk types.  If you need to add a chunk,
+ * define the name here, and add an invocation of the macro in png.c and
+ * wherever it's needed.
+ */
+#define PNG_IHDR png_byte png_IHDR[5] = { 73,  72,  68,  82, '\0'}
+#define PNG_IDAT png_byte png_IDAT[5] = { 73,  68,  65,  84, '\0'}
+#define PNG_IEND png_byte png_IEND[5] = { 73,  69,  78,  68, '\0'}
+#define PNG_PLTE png_byte png_PLTE[5] = { 80,  76,  84,  69, '\0'}
+#define PNG_bKGD png_byte png_bKGD[5] = { 98,  75,  71,  68, '\0'}
+#define PNG_cHRM png_byte png_cHRM[5] = { 99,  72,  82,  77, '\0'}
+#define PNG_gAMA png_byte png_gAMA[5] = {103,  65,  77,  65, '\0'}
+#define PNG_hIST png_byte png_hIST[5] = {104,  73,  83,  84, '\0'}
+#define PNG_iCCP png_byte png_iCCP[5] = {105,  67,  67,  80, '\0'}
+#define PNG_iTXt png_byte png_iTXt[5] = {105,  84,  88, 116, '\0'}
+#define PNG_oFFs png_byte png_oFFs[5] = {111,  70,  70, 115, '\0'}
+#define PNG_pCAL png_byte png_pCAL[5] = {112,  67,  65,  76, '\0'}
+#define PNG_sCAL png_byte png_sCAL[5] = {115,  67,  65,  76, '\0'}
+#define PNG_pHYs png_byte png_pHYs[5] = {112,  72,  89, 115, '\0'}
+#define PNG_sBIT png_byte png_sBIT[5] = {115,  66,  73,  84, '\0'}
+#define PNG_sPLT png_byte png_sPLT[5] = {115,  80,  76,  84, '\0'}
+#define PNG_sRGB png_byte png_sRGB[5] = {115,  82,  71,  66, '\0'}
+#define PNG_tEXt png_byte png_tEXt[5] = {116,  69,  88, 116, '\0'}
+#define PNG_tIME png_byte png_tIME[5] = {116,  73,  77,  69, '\0'}
+#define PNG_tRNS png_byte png_tRNS[5] = {116,  82,  78,  83, '\0'}
+#define PNG_zTXt png_byte png_zTXt[5] = {122,  84,  88, 116, '\0'}
+
+#ifdef PNG_USE_GLOBAL_ARRAYS
+PNG_EXPORT_VAR (png_byte FARDATA) png_IHDR[5];
+PNG_EXPORT_VAR (png_byte FARDATA) png_IDAT[5];
+PNG_EXPORT_VAR (png_byte FARDATA) png_IEND[5];
+PNG_EXPORT_VAR (png_byte FARDATA) png_PLTE[5];
+PNG_EXPORT_VAR (png_byte FARDATA) png_bKGD[5];
+PNG_EXPORT_VAR (png_byte FARDATA) png_cHRM[5];
+PNG_EXPORT_VAR (png_byte FARDATA) png_gAMA[5];
+PNG_EXPORT_VAR (png_byte FARDATA) png_hIST[5];
+PNG_EXPORT_VAR (png_byte FARDATA) png_iCCP[5];
+PNG_EXPORT_VAR (png_byte FARDATA) png_iTXt[5];
+PNG_EXPORT_VAR (png_byte FARDATA) png_oFFs[5];
+PNG_EXPORT_VAR (png_byte FARDATA) png_pCAL[5];
+PNG_EXPORT_VAR (png_byte FARDATA) png_sCAL[5];
+PNG_EXPORT_VAR (png_byte FARDATA) png_pHYs[5];
+PNG_EXPORT_VAR (png_byte FARDATA) png_sBIT[5];
+PNG_EXPORT_VAR (png_byte FARDATA) png_sPLT[5];
+PNG_EXPORT_VAR (png_byte FARDATA) png_sRGB[5];
+PNG_EXPORT_VAR (png_byte FARDATA) png_tEXt[5];
+PNG_EXPORT_VAR (png_byte FARDATA) png_tIME[5];
+PNG_EXPORT_VAR (png_byte FARDATA) png_tRNS[5];
+PNG_EXPORT_VAR (png_byte FARDATA) png_zTXt[5];
+#endif /* PNG_USE_GLOBAL_ARRAYS */
+
+#if defined(PNG_1_0_X) || defined (PNG_1_2_X)
+/* Initialize png_ptr struct for reading, and allocate any other memory.
+ * (old interface - DEPRECATED - use png_create_read_struct instead).
+ */
+extern PNG_EXPORT(void,png_read_init) PNGARG((png_structp png_ptr));
+#undef png_read_init
+#define png_read_init(png_ptr) png_read_init_3(&png_ptr, \
+    PNG_LIBPNG_VER_STRING,  png_sizeof(png_struct));
+#endif
+
+extern PNG_EXPORT(void,png_read_init_3) PNGARG((png_structpp ptr_ptr,
+    png_const_charp user_png_ver, png_size_t png_struct_size));
+#if defined(PNG_1_0_X) || defined (PNG_1_2_X)
+extern PNG_EXPORT(void,png_read_init_2) PNGARG((png_structp png_ptr,
+    png_const_charp user_png_ver, png_size_t png_struct_size, png_size_t
+    png_info_size));
+#endif
+
+#if defined(PNG_1_0_X) || defined (PNG_1_2_X)
+/* Initialize png_ptr struct for writing, and allocate any other memory.
+ * (old interface - DEPRECATED - use png_create_write_struct instead).
+ */
+extern PNG_EXPORT(void,png_write_init) PNGARG((png_structp png_ptr));
+#undef png_write_init
+#define png_write_init(png_ptr) png_write_init_3(&png_ptr, \
+    PNG_LIBPNG_VER_STRING, png_sizeof(png_struct));
+#endif
+
+extern PNG_EXPORT(void,png_write_init_3) PNGARG((png_structpp ptr_ptr,
+    png_const_charp user_png_ver, png_size_t png_struct_size));
+extern PNG_EXPORT(void,png_write_init_2) PNGARG((png_structp png_ptr,
+    png_const_charp user_png_ver, png_size_t png_struct_size, png_size_t
+    png_info_size));
+
+/* Allocate memory for an internal libpng struct */
+PNG_EXTERN png_voidp png_create_struct PNGARG((int type));
+
+/* Free memory from internal libpng struct */
+PNG_EXTERN void png_destroy_struct PNGARG((png_voidp struct_ptr));
+
+PNG_EXTERN png_voidp png_create_struct_2 PNGARG((int type, png_malloc_ptr
+  malloc_fn, png_voidp mem_ptr));
+PNG_EXTERN void png_destroy_struct_2 PNGARG((png_voidp struct_ptr,
+   png_free_ptr free_fn, png_voidp mem_ptr));
+
+/* Free any memory that info_ptr points to and reset struct. */
+PNG_EXTERN void png_info_destroy PNGARG((png_structp png_ptr,
+   png_infop info_ptr));
+
+#ifndef PNG_1_0_X
+/* Function to allocate memory for zlib. */
+PNG_EXTERN voidpf png_zalloc PNGARG((voidpf png_ptr, uInt items, uInt size));
+
+/* Function to free memory for zlib */
+PNG_EXTERN void png_zfree PNGARG((voidpf png_ptr, voidpf ptr));
+
+#ifdef PNG_SIZE_T
+/* Function to convert a sizeof an item to png_sizeof item */
+   PNG_EXTERN png_size_t PNGAPI png_convert_size PNGARG((size_t size));
+#endif
+
+/* Next four functions are used internally as callbacks.  PNGAPI is required
+ * but not PNG_EXPORT.  PNGAPI added at libpng version 1.2.3. */
+
+PNG_EXTERN void PNGAPI png_default_read_data PNGARG((png_structp png_ptr,
+   png_bytep data, png_size_t length));
+
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+PNG_EXTERN void PNGAPI png_push_fill_buffer PNGARG((png_structp png_ptr,
+   png_bytep buffer, png_size_t length));
+#endif
+
+PNG_EXTERN void PNGAPI png_default_write_data PNGARG((png_structp png_ptr,
+   png_bytep data, png_size_t length));
+
+#if defined(PNG_WRITE_FLUSH_SUPPORTED)
+#if !defined(PNG_NO_STDIO)
+PNG_EXTERN void PNGAPI png_default_flush PNGARG((png_structp png_ptr));
+#endif
+#endif
+#else /* PNG_1_0_X */
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+PNG_EXTERN void png_push_fill_buffer PNGARG((png_structp png_ptr,
+   png_bytep buffer, png_size_t length));
+#endif
+#endif /* PNG_1_0_X */
+
+/* Reset the CRC variable */
+PNG_EXTERN void png_reset_crc PNGARG((png_structp png_ptr));
+
+/* Write the "data" buffer to whatever output you are using. */
+PNG_EXTERN void png_write_data PNGARG((png_structp png_ptr, png_bytep data,
+   png_size_t length));
+
+/* Read data from whatever input you are using into the "data" buffer */
+PNG_EXTERN void png_read_data PNGARG((png_structp png_ptr, png_bytep data,
+   png_size_t length));
+
+/* Read bytes into buf, and update png_ptr->crc */
+PNG_EXTERN void png_crc_read PNGARG((png_structp png_ptr, png_bytep buf,
+   png_size_t length));
+
+/* Decompress data in a chunk that uses compression */
+#if defined(PNG_zTXt_SUPPORTED) || defined(PNG_iTXt_SUPPORTED) || \
+    defined(PNG_iCCP_SUPPORTED) || defined(PNG_sPLT_SUPPORTED)
+PNG_EXTERN png_charp png_decompress_chunk PNGARG((png_structp png_ptr,
+   int comp_type, png_charp chunkdata, png_size_t chunklength,
+   png_size_t prefix_length, png_size_t *data_length));
+#endif
+
+/* Read "skip" bytes, read the file crc, and (optionally) verify png_ptr->crc */
+PNG_EXTERN int png_crc_finish PNGARG((png_structp png_ptr, png_uint_32 skip));
+
+/* Read the CRC from the file and compare it to the libpng calculated CRC */
+PNG_EXTERN int png_crc_error PNGARG((png_structp png_ptr));
+
+/* Calculate the CRC over a section of data.  Note that we are only
+ * passing a maximum of 64K on systems that have this as a memory limit,
+ * since this is the maximum buffer size we can specify.
+ */
+PNG_EXTERN void png_calculate_crc PNGARG((png_structp png_ptr, png_bytep ptr,
+   png_size_t length));
+
+#if defined(PNG_WRITE_FLUSH_SUPPORTED)
+PNG_EXTERN void png_flush PNGARG((png_structp png_ptr));
+#endif
+
+/* simple function to write the signature */
+PNG_EXTERN void png_write_sig PNGARG((png_structp png_ptr));
+
+/* write various chunks */
+
+/* Write the IHDR chunk, and update the png_struct with the necessary
+ * information.
+ */
+PNG_EXTERN void png_write_IHDR PNGARG((png_structp png_ptr, png_uint_32 width,
+   png_uint_32 height,
+   int bit_depth, int color_type, int compression_method, int filter_method,
+   int interlace_method));
+
+PNG_EXTERN void png_write_PLTE PNGARG((png_structp png_ptr, png_colorp palette,
+   png_uint_32 num_pal));
+
+PNG_EXTERN void png_write_IDAT PNGARG((png_structp png_ptr, png_bytep data,
+   png_size_t length));
+
+PNG_EXTERN void png_write_IEND PNGARG((png_structp png_ptr));
+
+#if defined(PNG_WRITE_gAMA_SUPPORTED)
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+PNG_EXTERN void png_write_gAMA PNGARG((png_structp png_ptr, double file_gamma));
+#endif
+#ifdef PNG_FIXED_POINT_SUPPORTED
+PNG_EXTERN void png_write_gAMA_fixed PNGARG((png_structp png_ptr, png_fixed_point
+    file_gamma));
+#endif
+#endif
+
+#if defined(PNG_WRITE_sBIT_SUPPORTED)
+PNG_EXTERN void png_write_sBIT PNGARG((png_structp png_ptr, png_color_8p sbit,
+   int color_type));
+#endif
+
+#if defined(PNG_WRITE_cHRM_SUPPORTED)
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+PNG_EXTERN void png_write_cHRM PNGARG((png_structp png_ptr,
+   double white_x, double white_y,
+   double red_x, double red_y, double green_x, double green_y,
+   double blue_x, double blue_y));
+#endif
+#ifdef PNG_FIXED_POINT_SUPPORTED
+PNG_EXTERN void png_write_cHRM_fixed PNGARG((png_structp png_ptr,
+   png_fixed_point int_white_x, png_fixed_point int_white_y,
+   png_fixed_point int_red_x, png_fixed_point int_red_y, png_fixed_point
+   int_green_x, png_fixed_point int_green_y, png_fixed_point int_blue_x,
+   png_fixed_point int_blue_y));
+#endif
+#endif
+
+#if defined(PNG_WRITE_sRGB_SUPPORTED)
+PNG_EXTERN void png_write_sRGB PNGARG((png_structp png_ptr,
+   int intent));
+#endif
+
+#if defined(PNG_WRITE_iCCP_SUPPORTED)
+PNG_EXTERN void png_write_iCCP PNGARG((png_structp png_ptr,
+   png_charp name, int compression_type,
+   png_charp profile, int proflen));
+   /* Note to maintainer: profile should be png_bytep */
+#endif
+
+#if defined(PNG_WRITE_sPLT_SUPPORTED)
+PNG_EXTERN void png_write_sPLT PNGARG((png_structp png_ptr,
+   png_sPLT_tp palette));
+#endif
+
+#if defined(PNG_WRITE_tRNS_SUPPORTED)
+PNG_EXTERN void png_write_tRNS PNGARG((png_structp png_ptr, png_bytep trans,
+   png_color_16p values, int number, int color_type));
+#endif
+
+#if defined(PNG_WRITE_bKGD_SUPPORTED)
+PNG_EXTERN void png_write_bKGD PNGARG((png_structp png_ptr,
+   png_color_16p values, int color_type));
+#endif
+
+#if defined(PNG_WRITE_hIST_SUPPORTED)
+PNG_EXTERN void png_write_hIST PNGARG((png_structp png_ptr, png_uint_16p hist,
+   int num_hist));
+#endif
+
+#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \
+    defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
+PNG_EXTERN png_size_t png_check_keyword PNGARG((png_structp png_ptr,
+   png_charp key, png_charpp new_key));
+#endif
+
+#if defined(PNG_WRITE_tEXt_SUPPORTED)
+PNG_EXTERN void png_write_tEXt PNGARG((png_structp png_ptr, png_charp key,
+   png_charp text, png_size_t text_len));
+#endif
+
+#if defined(PNG_WRITE_zTXt_SUPPORTED)
+PNG_EXTERN void png_write_zTXt PNGARG((png_structp png_ptr, png_charp key,
+   png_charp text, png_size_t text_len, int compression));
+#endif
+
+#if defined(PNG_WRITE_iTXt_SUPPORTED)
+PNG_EXTERN void png_write_iTXt PNGARG((png_structp png_ptr,
+   int compression, png_charp key, png_charp lang, png_charp lang_key,
+   png_charp text));
+#endif
+
+#if defined(PNG_TEXT_SUPPORTED)  /* Added at version 1.0.14 and 1.2.4 */
+PNG_EXTERN int png_set_text_2 PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_textp text_ptr, int num_text));
+#endif
+
+#if defined(PNG_WRITE_oFFs_SUPPORTED)
+PNG_EXTERN void png_write_oFFs PNGARG((png_structp png_ptr,
+   png_int_32 x_offset, png_int_32 y_offset, int unit_type));
+#endif
+
+#if defined(PNG_WRITE_pCAL_SUPPORTED)
+PNG_EXTERN void png_write_pCAL PNGARG((png_structp png_ptr, png_charp purpose,
+   png_int_32 X0, png_int_32 X1, int type, int nparams,
+   png_charp units, png_charpp params));
+#endif
+
+#if defined(PNG_WRITE_pHYs_SUPPORTED)
+PNG_EXTERN void png_write_pHYs PNGARG((png_structp png_ptr,
+   png_uint_32 x_pixels_per_unit, png_uint_32 y_pixels_per_unit,
+   int unit_type));
+#endif
+
+#if defined(PNG_WRITE_tIME_SUPPORTED)
+PNG_EXTERN void png_write_tIME PNGARG((png_structp png_ptr,
+   png_timep mod_time));
+#endif
+
+#if defined(PNG_WRITE_sCAL_SUPPORTED)
+#if defined(PNG_FLOATING_POINT_SUPPORTED) && !defined(PNG_NO_STDIO)
+PNG_EXTERN void png_write_sCAL PNGARG((png_structp png_ptr,
+   int unit, double width, double height));
+#else
+#ifdef PNG_FIXED_POINT_SUPPORTED
+PNG_EXTERN void png_write_sCAL_s PNGARG((png_structp png_ptr,
+   int unit, png_charp width, png_charp height));
+#endif
+#endif
+#endif
+
+/* Called when finished processing a row of data */
+PNG_EXTERN void png_write_finish_row PNGARG((png_structp png_ptr));
+
+/* Internal use only.   Called before first row of data */
+PNG_EXTERN void png_write_start_row PNGARG((png_structp png_ptr));
+
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+PNG_EXTERN void png_build_gamma_table PNGARG((png_structp png_ptr));
+#endif
+
+/* combine a row of data, dealing with alpha, etc. if requested */
+PNG_EXTERN void png_combine_row PNGARG((png_structp png_ptr, png_bytep row,
+   int mask));
+
+#if defined(PNG_READ_INTERLACING_SUPPORTED)
+/* expand an interlaced row */
+/* OLD pre-1.0.9 interface:
+PNG_EXTERN void png_do_read_interlace PNGARG((png_row_infop row_info,
+   png_bytep row, int pass, png_uint_32 transformations));
+ */
+PNG_EXTERN void png_do_read_interlace PNGARG((png_structp png_ptr));
+#endif
+
+/* GRR TO DO (2.0 or whenever):  simplify other internal calling interfaces */
+
+#if defined(PNG_WRITE_INTERLACING_SUPPORTED)
+/* grab pixels out of a row for an interlaced pass */
+PNG_EXTERN void png_do_write_interlace PNGARG((png_row_infop row_info,
+   png_bytep row, int pass));
+#endif
+
+/* unfilter a row */
+PNG_EXTERN void png_read_filter_row PNGARG((png_structp png_ptr,
+   png_row_infop row_info, png_bytep row, png_bytep prev_row, int filter));
+
+/* Choose the best filter to use and filter the row data */
+PNG_EXTERN void png_write_find_filter PNGARG((png_structp png_ptr,
+   png_row_infop row_info));
+
+/* Write out the filtered row. */
+PNG_EXTERN void png_write_filtered_row PNGARG((png_structp png_ptr,
+   png_bytep filtered_row));
+/* finish a row while reading, dealing with interlacing passes, etc. */
+PNG_EXTERN void png_read_finish_row PNGARG((png_structp png_ptr));
+
+/* initialize the row buffers, etc. */
+PNG_EXTERN void png_read_start_row PNGARG((png_structp png_ptr));
+/* optional call to update the users info structure */
+PNG_EXTERN void png_read_transform_info PNGARG((png_structp png_ptr,
+   png_infop info_ptr));
+
+/* these are the functions that do the transformations */
+#if defined(PNG_READ_FILLER_SUPPORTED)
+PNG_EXTERN void png_do_read_filler PNGARG((png_row_infop row_info,
+   png_bytep row, png_uint_32 filler, png_uint_32 flags));
+#endif
+
+#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED)
+PNG_EXTERN void png_do_read_swap_alpha PNGARG((png_row_infop row_info,
+   png_bytep row));
+#endif
+
+#if defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
+PNG_EXTERN void png_do_write_swap_alpha PNGARG((png_row_infop row_info,
+   png_bytep row));
+#endif
+
+#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED)
+PNG_EXTERN void png_do_read_invert_alpha PNGARG((png_row_infop row_info,
+   png_bytep row));
+#endif
+
+#if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
+PNG_EXTERN void png_do_write_invert_alpha PNGARG((png_row_infop row_info,
+   png_bytep row));
+#endif
+
+#if defined(PNG_WRITE_FILLER_SUPPORTED) || \
+    defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
+PNG_EXTERN void png_do_strip_filler PNGARG((png_row_infop row_info,
+   png_bytep row, png_uint_32 flags));
+#endif
+
+#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
+PNG_EXTERN void png_do_swap PNGARG((png_row_infop row_info, png_bytep row));
+#endif
+
+#if defined(PNG_READ_PACKSWAP_SUPPORTED) || defined(PNG_WRITE_PACKSWAP_SUPPORTED)
+PNG_EXTERN void png_do_packswap PNGARG((png_row_infop row_info, png_bytep row));
+#endif
+
+#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+PNG_EXTERN int png_do_rgb_to_gray PNGARG((png_structp png_ptr, png_row_infop
+   row_info, png_bytep row));
+#endif
+
+#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
+PNG_EXTERN void png_do_gray_to_rgb PNGARG((png_row_infop row_info,
+   png_bytep row));
+#endif
+
+#if defined(PNG_READ_PACK_SUPPORTED)
+PNG_EXTERN void png_do_unpack PNGARG((png_row_infop row_info, png_bytep row));
+#endif
+
+#if defined(PNG_READ_SHIFT_SUPPORTED)
+PNG_EXTERN void png_do_unshift PNGARG((png_row_infop row_info, png_bytep row,
+   png_color_8p sig_bits));
+#endif
+
+#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
+PNG_EXTERN void png_do_invert PNGARG((png_row_infop row_info, png_bytep row));
+#endif
+
+#if defined(PNG_READ_16_TO_8_SUPPORTED)
+PNG_EXTERN void png_do_chop PNGARG((png_row_infop row_info, png_bytep row));
+#endif
+
+#if defined(PNG_READ_DITHER_SUPPORTED)
+PNG_EXTERN void png_do_dither PNGARG((png_row_infop row_info,
+   png_bytep row, png_bytep palette_lookup, png_bytep dither_lookup));
+
+#  if defined(PNG_CORRECT_PALETTE_SUPPORTED)
+PNG_EXTERN void png_correct_palette PNGARG((png_structp png_ptr,
+   png_colorp palette, int num_palette));
+#  endif
+#endif
+
+#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
+PNG_EXTERN void png_do_bgr PNGARG((png_row_infop row_info, png_bytep row));
+#endif
+
+#if defined(PNG_WRITE_PACK_SUPPORTED)
+PNG_EXTERN void png_do_pack PNGARG((png_row_infop row_info,
+   png_bytep row, png_uint_32 bit_depth));
+#endif
+
+#if defined(PNG_WRITE_SHIFT_SUPPORTED)
+PNG_EXTERN void png_do_shift PNGARG((png_row_infop row_info, png_bytep row,
+   png_color_8p bit_depth));
+#endif
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+PNG_EXTERN void png_do_background PNGARG((png_row_infop row_info, png_bytep row,
+   png_color_16p trans_values, png_color_16p background,
+   png_color_16p background_1,
+   png_bytep gamma_table, png_bytep gamma_from_1, png_bytep gamma_to_1,
+   png_uint_16pp gamma_16, png_uint_16pp gamma_16_from_1,
+   png_uint_16pp gamma_16_to_1, int gamma_shift));
+#else
+PNG_EXTERN void png_do_background PNGARG((png_row_infop row_info, png_bytep row,
+   png_color_16p trans_values, png_color_16p background));
+#endif
+#endif
+
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+PNG_EXTERN void png_do_gamma PNGARG((png_row_infop row_info, png_bytep row,
+   png_bytep gamma_table, png_uint_16pp gamma_16_table,
+   int gamma_shift));
+#endif
+
+#if defined(PNG_READ_EXPAND_SUPPORTED)
+PNG_EXTERN void png_do_expand_palette PNGARG((png_row_infop row_info,
+   png_bytep row, png_colorp palette, png_bytep trans, int num_trans));
+PNG_EXTERN void png_do_expand PNGARG((png_row_infop row_info,
+   png_bytep row, png_color_16p trans_value));
+#endif
+
+/* The following decodes the appropriate chunks, and does error correction,
+ * then calls the appropriate callback for the chunk if it is valid.
+ */
+
+/* decode the IHDR chunk */
+PNG_EXTERN void png_handle_IHDR PNGARG((png_structp png_ptr, png_infop info_ptr,
+   png_uint_32 length));
+PNG_EXTERN void png_handle_PLTE PNGARG((png_structp png_ptr, png_infop info_ptr,
+   png_uint_32 length));
+PNG_EXTERN void png_handle_IEND PNGARG((png_structp png_ptr, png_infop info_ptr,
+   png_uint_32 length));
+
+#if defined(PNG_READ_bKGD_SUPPORTED)
+PNG_EXTERN void png_handle_bKGD PNGARG((png_structp png_ptr, png_infop info_ptr,
+   png_uint_32 length));
+#endif
+
+#if defined(PNG_READ_cHRM_SUPPORTED)
+PNG_EXTERN void png_handle_cHRM PNGARG((png_structp png_ptr, png_infop info_ptr,
+   png_uint_32 length));
+#endif
+
+#if defined(PNG_READ_gAMA_SUPPORTED)
+PNG_EXTERN void png_handle_gAMA PNGARG((png_structp png_ptr, png_infop info_ptr,
+   png_uint_32 length));
+#endif
+
+#if defined(PNG_READ_hIST_SUPPORTED)
+PNG_EXTERN void png_handle_hIST PNGARG((png_structp png_ptr, png_infop info_ptr,
+   png_uint_32 length));
+#endif
+
+#if defined(PNG_READ_iCCP_SUPPORTED)
+extern void png_handle_iCCP PNGARG((png_structp png_ptr, png_infop info_ptr,
+   png_uint_32 length));
+#endif /* PNG_READ_iCCP_SUPPORTED */
+
+#if defined(PNG_READ_iTXt_SUPPORTED)
+PNG_EXTERN void png_handle_iTXt PNGARG((png_structp png_ptr, png_infop info_ptr,
+   png_uint_32 length));
+#endif
+
+#if defined(PNG_READ_oFFs_SUPPORTED)
+PNG_EXTERN void png_handle_oFFs PNGARG((png_structp png_ptr, png_infop info_ptr,
+   png_uint_32 length));
+#endif
+
+#if defined(PNG_READ_pCAL_SUPPORTED)
+PNG_EXTERN void png_handle_pCAL PNGARG((png_structp png_ptr, png_infop info_ptr,
+   png_uint_32 length));
+#endif
+
+#if defined(PNG_READ_pHYs_SUPPORTED)
+PNG_EXTERN void png_handle_pHYs PNGARG((png_structp png_ptr, png_infop info_ptr,
+   png_uint_32 length));
+#endif
+
+#if defined(PNG_READ_sBIT_SUPPORTED)
+PNG_EXTERN void png_handle_sBIT PNGARG((png_structp png_ptr, png_infop info_ptr,
+   png_uint_32 length));
+#endif
+
+#if defined(PNG_READ_sCAL_SUPPORTED)
+PNG_EXTERN void png_handle_sCAL PNGARG((png_structp png_ptr, png_infop info_ptr,
+   png_uint_32 length));
+#endif
+
+#if defined(PNG_READ_sPLT_SUPPORTED)
+extern void png_handle_sPLT PNGARG((png_structp png_ptr, png_infop info_ptr,
+   png_uint_32 length));
+#endif /* PNG_READ_sPLT_SUPPORTED */
+
+#if defined(PNG_READ_sRGB_SUPPORTED)
+PNG_EXTERN void png_handle_sRGB PNGARG((png_structp png_ptr, png_infop info_ptr,
+   png_uint_32 length));
+#endif
+
+#if defined(PNG_READ_tEXt_SUPPORTED)
+PNG_EXTERN void png_handle_tEXt PNGARG((png_structp png_ptr, png_infop info_ptr,
+   png_uint_32 length));
+#endif
+
+#if defined(PNG_READ_tIME_SUPPORTED)
+PNG_EXTERN void png_handle_tIME PNGARG((png_structp png_ptr, png_infop info_ptr,
+   png_uint_32 length));
+#endif
+
+#if defined(PNG_READ_tRNS_SUPPORTED)
+PNG_EXTERN void png_handle_tRNS PNGARG((png_structp png_ptr, png_infop info_ptr,
+   png_uint_32 length));
+#endif
+
+#if defined(PNG_READ_zTXt_SUPPORTED)
+PNG_EXTERN void png_handle_zTXt PNGARG((png_structp png_ptr, png_infop info_ptr,
+   png_uint_32 length));
+#endif
+
+PNG_EXTERN void png_handle_unknown PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_uint_32 length));
+
+PNG_EXTERN void png_check_chunk_name PNGARG((png_structp png_ptr,
+   png_bytep chunk_name));
+
+/* handle the transformations for reading and writing */
+PNG_EXTERN void png_do_read_transformations PNGARG((png_structp png_ptr));
+PNG_EXTERN void png_do_write_transformations PNGARG((png_structp png_ptr));
+
+PNG_EXTERN void png_init_read_transformations PNGARG((png_structp png_ptr));
+
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+PNG_EXTERN void png_push_read_chunk PNGARG((png_structp png_ptr,
+   png_infop info_ptr));
+PNG_EXTERN void png_push_read_sig PNGARG((png_structp png_ptr,
+   png_infop info_ptr));
+PNG_EXTERN void png_push_check_crc PNGARG((png_structp png_ptr));
+PNG_EXTERN void png_push_crc_skip PNGARG((png_structp png_ptr,
+   png_uint_32 length));
+PNG_EXTERN void png_push_crc_finish PNGARG((png_structp png_ptr));
+PNG_EXTERN void png_push_save_buffer PNGARG((png_structp png_ptr));
+PNG_EXTERN void png_push_restore_buffer PNGARG((png_structp png_ptr,
+   png_bytep buffer, png_size_t buffer_length));
+PNG_EXTERN void png_push_read_IDAT PNGARG((png_structp png_ptr));
+PNG_EXTERN void png_process_IDAT_data PNGARG((png_structp png_ptr,
+   png_bytep buffer, png_size_t buffer_length));
+PNG_EXTERN void png_push_process_row PNGARG((png_structp png_ptr));
+PNG_EXTERN void png_push_handle_unknown PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_uint_32 length));
+PNG_EXTERN void png_push_have_info PNGARG((png_structp png_ptr,
+   png_infop info_ptr));
+PNG_EXTERN void png_push_have_end PNGARG((png_structp png_ptr,
+   png_infop info_ptr));
+PNG_EXTERN void png_push_have_row PNGARG((png_structp png_ptr, png_bytep row));
+PNG_EXTERN void png_push_read_end PNGARG((png_structp png_ptr,
+   png_infop info_ptr));
+PNG_EXTERN void png_process_some_data PNGARG((png_structp png_ptr,
+   png_infop info_ptr));
+PNG_EXTERN void png_read_push_finish_row PNGARG((png_structp png_ptr));
+#if defined(PNG_READ_tEXt_SUPPORTED)
+PNG_EXTERN void png_push_handle_tEXt PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_uint_32 length));
+PNG_EXTERN void png_push_read_tEXt PNGARG((png_structp png_ptr,
+   png_infop info_ptr));
+#endif
+#if defined(PNG_READ_zTXt_SUPPORTED)
+PNG_EXTERN void png_push_handle_zTXt PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_uint_32 length));
+PNG_EXTERN void png_push_read_zTXt PNGARG((png_structp png_ptr,
+   png_infop info_ptr));
+#endif
+#if defined(PNG_READ_iTXt_SUPPORTED)
+PNG_EXTERN void png_push_handle_iTXt PNGARG((png_structp png_ptr,
+   png_infop info_ptr, png_uint_32 length));
+PNG_EXTERN void png_push_read_iTXt PNGARG((png_structp png_ptr,
+   png_infop info_ptr));
+#endif
+
+#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
+
+#ifdef PNG_MNG_FEATURES_SUPPORTED
+PNG_EXTERN void png_do_read_intrapixel PNGARG((png_row_infop row_info,
+   png_bytep row));
+PNG_EXTERN void png_do_write_intrapixel PNGARG((png_row_infop row_info,
+   png_bytep row));
+#endif
+
+#if defined(PNG_ASSEMBLER_CODE_SUPPORTED)
+#if defined(PNG_MMX_CODE_SUPPORTED)
+/* png.c */ /* PRIVATE */
+PNG_EXTERN void png_init_mmx_flags PNGARG((png_structp png_ptr));
+#endif
+#endif
+
+#if defined(PNG_INCH_CONVERSIONS) && defined(PNG_FLOATING_POINT_SUPPORTED)
+PNG_EXTERN png_uint_32 png_get_pixels_per_inch PNGARG((png_structp png_ptr,
+png_infop info_ptr));
+
+PNG_EXTERN png_uint_32 png_get_x_pixels_per_inch PNGARG((png_structp png_ptr,
+png_infop info_ptr));
+
+PNG_EXTERN png_uint_32 png_get_y_pixels_per_inch PNGARG((png_structp png_ptr,
+png_infop info_ptr));
+
+PNG_EXTERN float png_get_x_offset_inches PNGARG((png_structp png_ptr,
+png_infop info_ptr));
+
+PNG_EXTERN float png_get_y_offset_inches PNGARG((png_structp png_ptr,
+png_infop info_ptr));
+
+#if defined(PNG_pHYs_SUPPORTED)
+PNG_EXTERN png_uint_32 png_get_pHYs_dpi PNGARG((png_structp png_ptr,
+png_infop info_ptr, png_uint_32 *res_x, png_uint_32 *res_y, int *unit_type));
+#endif /* PNG_pHYs_SUPPORTED */
+#endif  /* PNG_INCH_CONVERSIONS && PNG_FLOATING_POINT_SUPPORTED */
+
+/* Maintainer: Put new private prototypes here ^ and in libpngpf.3 */
+
+#endif /* PNG_INTERNAL */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* PNG_VERSION_INFO_ONLY */
+/* do not put anything past this line */
+#endif /* PNG_H */
diff --git a/distrib/libpng-1.2.19/pngconf.h b/distrib/libpng-1.2.19/pngconf.h
new file mode 100644
index 0000000..43dfe04
--- /dev/null
+++ b/distrib/libpng-1.2.19/pngconf.h
@@ -0,0 +1,1535 @@
+
+/* pngconf.h - machine configurable file for libpng
+ *
+ * libpng version 1.2.19 - August 18, 2007
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1998-2007 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ */
+
+/* Any machine specific code is near the front of this file, so if you
+ * are configuring libpng for a machine, you may want to read the section
+ * starting here down to where it starts to typedef png_color, png_text,
+ * and png_info.
+ */
+
+#ifndef PNGCONF_H
+#define PNGCONF_H
+
+#define PNG_1_2_X
+
+/* 
+ * PNG_USER_CONFIG has to be defined on the compiler command line. This
+ * includes the resource compiler for Windows DLL configurations.
+ */
+#ifdef PNG_USER_CONFIG
+#  ifndef PNG_USER_PRIVATEBUILD
+#    define PNG_USER_PRIVATEBUILD
+#  endif
+#include "pngusr.h"
+#endif
+
+/* PNG_CONFIGURE_LIBPNG is set by the "configure" script. */
+#ifdef PNG_CONFIGURE_LIBPNG
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+#endif
+
+/*
+ * Added at libpng-1.2.8
+ *  
+ * If you create a private DLL you need to define in "pngusr.h" the followings:
+ * #define PNG_USER_PRIVATEBUILD <Describes by whom and why this version of
+ *        the DLL was built>
+ *  e.g. #define PNG_USER_PRIVATEBUILD "Build by MyCompany for xyz reasons."
+ * #define PNG_USER_DLLFNAME_POSTFIX <two-letter postfix that serve to
+ *        distinguish your DLL from those of the official release. These
+ *        correspond to the trailing letters that come after the version
+ *        number and must match your private DLL name>
+ *  e.g. // private DLL "libpng13gx.dll"
+ *       #define PNG_USER_DLLFNAME_POSTFIX "gx"
+ * 
+ * The following macros are also at your disposal if you want to complete the 
+ * DLL VERSIONINFO structure.
+ * - PNG_USER_VERSIONINFO_COMMENTS
+ * - PNG_USER_VERSIONINFO_COMPANYNAME
+ * - PNG_USER_VERSIONINFO_LEGALTRADEMARKS
+ */
+
+#ifdef __STDC__
+#ifdef SPECIALBUILD
+#  pragma message("PNG_LIBPNG_SPECIALBUILD (and deprecated SPECIALBUILD)\
+ are now LIBPNG reserved macros. Use PNG_USER_PRIVATEBUILD instead.")
+#endif
+
+#ifdef PRIVATEBUILD
+# pragma message("PRIVATEBUILD is deprecated.\
+ Use PNG_USER_PRIVATEBUILD instead.")
+# define PNG_USER_PRIVATEBUILD PRIVATEBUILD
+#endif
+#endif /* __STDC__ */
+
+#ifndef PNG_VERSION_INFO_ONLY
+
+/* End of material added to libpng-1.2.8 */
+
+/* Added at libpng-1.2.19 */
+#ifndef PNG_NO_WARN_UNINITIALIZED_ROW
+#  ifndef PNG_WARN_UNINITIALIZED_ROW
+#    define PNG_WARN_UNINITIALIZED_ROW 1 /* 0: warning; 1: error */
+#  endif
+#endif
+/* End of material added at libpng-1.2.19 */
+
+/* This is the size of the compression buffer, and thus the size of
+ * an IDAT chunk.  Make this whatever size you feel is best for your
+ * machine.  One of these will be allocated per png_struct.  When this
+ * is full, it writes the data to the disk, and does some other
+ * calculations.  Making this an extremely small size will slow
+ * the library down, but you may want to experiment to determine
+ * where it becomes significant, if you are concerned with memory
+ * usage.  Note that zlib allocates at least 32Kb also.  For readers,
+ * this describes the size of the buffer available to read the data in.
+ * Unless this gets smaller than the size of a row (compressed),
+ * it should not make much difference how big this is.
+ */
+
+#ifndef PNG_ZBUF_SIZE
+#  define PNG_ZBUF_SIZE 8192
+#endif
+
+/* Enable if you want a write-only libpng */
+
+#ifndef PNG_NO_READ_SUPPORTED
+#  define PNG_READ_SUPPORTED
+#endif
+
+/* Enable if you want a read-only libpng */
+
+#ifndef PNG_NO_WRITE_SUPPORTED
+#  define PNG_WRITE_SUPPORTED
+#endif
+
+/* Enabled by default in 1.2.0.  You can disable this if you don't need to
+   support PNGs that are embedded in MNG datastreams */
+#if !defined(PNG_1_0_X) && !defined(PNG_NO_MNG_FEATURES)
+#  ifndef PNG_MNG_FEATURES_SUPPORTED
+#    define PNG_MNG_FEATURES_SUPPORTED
+#  endif
+#endif
+
+#ifndef PNG_NO_FLOATING_POINT_SUPPORTED
+#  ifndef PNG_FLOATING_POINT_SUPPORTED
+#    define PNG_FLOATING_POINT_SUPPORTED
+#  endif
+#endif
+
+/* If you are running on a machine where you cannot allocate more
+ * than 64K of memory at once, uncomment this.  While libpng will not
+ * normally need that much memory in a chunk (unless you load up a very
+ * large file), zlib needs to know how big of a chunk it can use, and
+ * libpng thus makes sure to check any memory allocation to verify it
+ * will fit into memory.
+#define PNG_MAX_MALLOC_64K
+ */
+#if defined(MAXSEG_64K) && !defined(PNG_MAX_MALLOC_64K)
+#  define PNG_MAX_MALLOC_64K
+#endif
+
+/* Special munging to support doing things the 'cygwin' way:
+ * 'Normal' png-on-win32 defines/defaults:
+ *   PNG_BUILD_DLL -- building dll
+ *   PNG_USE_DLL   -- building an application, linking to dll
+ *   (no define)   -- building static library, or building an
+ *                    application and linking to the static lib
+ * 'Cygwin' defines/defaults:
+ *   PNG_BUILD_DLL -- (ignored) building the dll
+ *   (no define)   -- (ignored) building an application, linking to the dll
+ *   PNG_STATIC    -- (ignored) building the static lib, or building an 
+ *                    application that links to the static lib.
+ *   ALL_STATIC    -- (ignored) building various static libs, or building an 
+ *                    application that links to the static libs.
+ * Thus,
+ * a cygwin user should define either PNG_BUILD_DLL or PNG_STATIC, and
+ * this bit of #ifdefs will define the 'correct' config variables based on
+ * that. If a cygwin user *wants* to define 'PNG_USE_DLL' that's okay, but
+ * unnecessary.
+ *
+ * Also, the precedence order is:
+ *   ALL_STATIC (since we can't #undef something outside our namespace)
+ *   PNG_BUILD_DLL
+ *   PNG_STATIC
+ *   (nothing) == PNG_USE_DLL
+ * 
+ * CYGWIN (2002-01-20): The preceding is now obsolete. With the advent
+ *   of auto-import in binutils, we no longer need to worry about 
+ *   __declspec(dllexport) / __declspec(dllimport) and friends.  Therefore,
+ *   we don't need to worry about PNG_STATIC or ALL_STATIC when it comes
+ *   to __declspec() stuff.  However, we DO need to worry about 
+ *   PNG_BUILD_DLL and PNG_STATIC because those change some defaults
+ *   such as CONSOLE_IO and whether GLOBAL_ARRAYS are allowed.
+ */
+#if defined(__CYGWIN__)
+#  if defined(ALL_STATIC)
+#    if defined(PNG_BUILD_DLL)
+#      undef PNG_BUILD_DLL
+#    endif
+#    if defined(PNG_USE_DLL)
+#      undef PNG_USE_DLL
+#    endif
+#    if defined(PNG_DLL)
+#      undef PNG_DLL
+#    endif
+#    if !defined(PNG_STATIC)
+#      define PNG_STATIC
+#    endif
+#  else
+#    if defined (PNG_BUILD_DLL)
+#      if defined(PNG_STATIC)
+#        undef PNG_STATIC
+#      endif
+#      if defined(PNG_USE_DLL)
+#        undef PNG_USE_DLL
+#      endif
+#      if !defined(PNG_DLL)
+#        define PNG_DLL
+#      endif
+#    else
+#      if defined(PNG_STATIC)
+#        if defined(PNG_USE_DLL)
+#          undef PNG_USE_DLL
+#        endif
+#        if defined(PNG_DLL)
+#          undef PNG_DLL
+#        endif
+#      else
+#        if !defined(PNG_USE_DLL)
+#          define PNG_USE_DLL
+#        endif
+#        if !defined(PNG_DLL)
+#          define PNG_DLL
+#        endif
+#      endif  
+#    endif  
+#  endif
+#endif
+
+/* This protects us against compilers that run on a windowing system
+ * and thus don't have or would rather us not use the stdio types:
+ * stdin, stdout, and stderr.  The only one currently used is stderr
+ * in png_error() and png_warning().  #defining PNG_NO_CONSOLE_IO will
+ * prevent these from being compiled and used. #defining PNG_NO_STDIO
+ * will also prevent these, plus will prevent the entire set of stdio
+ * macros and functions (FILE *, printf, etc.) from being compiled and used,
+ * unless (PNG_DEBUG > 0) has been #defined.
+ *
+ * #define PNG_NO_CONSOLE_IO
+ * #define PNG_NO_STDIO
+ */
+
+#if defined(_WIN32_WCE)
+#  include <windows.h>
+   /* Console I/O functions are not supported on WindowsCE */
+#  define PNG_NO_CONSOLE_IO
+#  ifdef PNG_DEBUG
+#    undef PNG_DEBUG
+#  endif
+#endif
+
+#ifdef PNG_BUILD_DLL
+#  ifndef PNG_CONSOLE_IO_SUPPORTED
+#    ifndef PNG_NO_CONSOLE_IO
+#      define PNG_NO_CONSOLE_IO
+#    endif
+#  endif
+#endif
+
+#  ifdef PNG_NO_STDIO
+#    ifndef PNG_NO_CONSOLE_IO
+#      define PNG_NO_CONSOLE_IO
+#    endif
+#    ifdef PNG_DEBUG
+#      if (PNG_DEBUG > 0)
+#        include <stdio.h>
+#      endif
+#    endif
+#  else
+#    if !defined(_WIN32_WCE)
+/* "stdio.h" functions are not supported on WindowsCE */
+#      include <stdio.h>
+#    endif
+#  endif
+
+/* This macro protects us against machines that don't have function
+ * prototypes (ie K&R style headers).  If your compiler does not handle
+ * function prototypes, define this macro and use the included ansi2knr.
+ * I've always been able to use _NO_PROTO as the indicator, but you may
+ * need to drag the empty declaration out in front of here, or change the
+ * ifdef to suit your own needs.
+ */
+#ifndef PNGARG
+
+#ifdef OF /* zlib prototype munger */
+#  define PNGARG(arglist) OF(arglist)
+#else
+
+#ifdef _NO_PROTO
+#  define PNGARG(arglist) ()
+#  ifndef PNG_TYPECAST_NULL
+#     define PNG_TYPECAST_NULL
+#  endif
+#else
+#  define PNGARG(arglist) arglist
+#endif /* _NO_PROTO */
+
+
+#endif /* OF */
+
+#endif /* PNGARG */
+
+/* Try to determine if we are compiling on a Mac.  Note that testing for
+ * just __MWERKS__ is not good enough, because the Codewarrior is now used
+ * on non-Mac platforms.
+ */
+#ifndef MACOS
+#  if (defined(__MWERKS__) && defined(macintosh)) || defined(applec) || \
+      defined(THINK_C) || defined(__SC__) || defined(TARGET_OS_MAC)
+#    define MACOS
+#  endif
+#endif
+
+/* enough people need this for various reasons to include it here */
+#if !defined(MACOS) && !defined(RISCOS) && !defined(_WIN32_WCE)
+#  include <sys/types.h>
+#endif
+
+#if !defined(PNG_SETJMP_NOT_SUPPORTED) && !defined(PNG_NO_SETJMP_SUPPORTED)
+#  define PNG_SETJMP_SUPPORTED
+#endif
+
+#ifdef PNG_SETJMP_SUPPORTED
+/* This is an attempt to force a single setjmp behaviour on Linux.  If
+ * the X config stuff didn't define _BSD_SOURCE we wouldn't need this.
+ */
+
+#  ifdef __linux__
+#    ifdef _BSD_SOURCE
+#      define PNG_SAVE_BSD_SOURCE
+#      undef _BSD_SOURCE
+#    endif
+#    ifdef _SETJMP_H
+     /* If you encounter a compiler error here, see the explanation
+      * near the end of INSTALL.
+      */
+         __png.h__ already includes setjmp.h;
+         __dont__ include it again.;
+#    endif
+#  endif /* __linux__ */
+
+   /* include setjmp.h for error handling */
+#  include <setjmp.h>
+
+#  ifdef __linux__
+#    ifdef PNG_SAVE_BSD_SOURCE
+#      define _BSD_SOURCE
+#      undef PNG_SAVE_BSD_SOURCE
+#    endif
+#  endif /* __linux__ */
+#endif /* PNG_SETJMP_SUPPORTED */
+
+#ifdef BSD
+#  include <strings.h>
+#else
+#  include <string.h>
+#endif
+
+/* Other defines for things like memory and the like can go here.  */
+#ifdef PNG_INTERNAL
+
+#include <stdlib.h>
+
+/* The functions exported by PNG_EXTERN are PNG_INTERNAL functions, which
+ * aren't usually used outside the library (as far as I know), so it is
+ * debatable if they should be exported at all.  In the future, when it is
+ * possible to have run-time registry of chunk-handling functions, some of
+ * these will be made available again.
+#define PNG_EXTERN extern
+ */
+#define PNG_EXTERN
+
+/* Other defines specific to compilers can go here.  Try to keep
+ * them inside an appropriate ifdef/endif pair for portability.
+ */
+
+#if defined(PNG_FLOATING_POINT_SUPPORTED)
+#  if defined(MACOS)
+     /* We need to check that <math.h> hasn't already been included earlier
+      * as it seems it doesn't agree with <fp.h>, yet we should really use
+      * <fp.h> if possible.
+      */
+#    if !defined(__MATH_H__) && !defined(__MATH_H) && !defined(__cmath__)
+#      include <fp.h>
+#    endif
+#  else
+#    include <math.h>
+#  endif
+#  if defined(_AMIGA) && defined(__SASC) && defined(_M68881)
+     /* Amiga SAS/C: We must include builtin FPU functions when compiling using
+      * MATH=68881
+      */
+#    include <m68881.h>
+#  endif
+#endif
+
+/* Codewarrior on NT has linking problems without this. */
+#if (defined(__MWERKS__) && defined(WIN32)) || defined(__STDC__)
+#  define PNG_ALWAYS_EXTERN
+#endif
+
+/* This provides the non-ANSI (far) memory allocation routines. */
+#if defined(__TURBOC__) && defined(__MSDOS__)
+#  include <mem.h>
+#  include <alloc.h>
+#endif
+
+/* I have no idea why is this necessary... */
+#if defined(_MSC_VER) && (defined(WIN32) || defined(_Windows) || \
+    defined(_WINDOWS) || defined(_WIN32) || defined(__WIN32__))
+#  include <malloc.h>
+#endif
+
+/* This controls how fine the dithering gets.  As this allocates
+ * a largish chunk of memory (32K), those who are not as concerned
+ * with dithering quality can decrease some or all of these.
+ */
+#ifndef PNG_DITHER_RED_BITS
+#  define PNG_DITHER_RED_BITS 5
+#endif
+#ifndef PNG_DITHER_GREEN_BITS
+#  define PNG_DITHER_GREEN_BITS 5
+#endif
+#ifndef PNG_DITHER_BLUE_BITS
+#  define PNG_DITHER_BLUE_BITS 5
+#endif
+
+/* This controls how fine the gamma correction becomes when you
+ * are only interested in 8 bits anyway.  Increasing this value
+ * results in more memory being used, and more pow() functions
+ * being called to fill in the gamma tables.  Don't set this value
+ * less then 8, and even that may not work (I haven't tested it).
+ */
+
+#ifndef PNG_MAX_GAMMA_8
+#  define PNG_MAX_GAMMA_8 11
+#endif
+
+/* This controls how much a difference in gamma we can tolerate before
+ * we actually start doing gamma conversion.
+ */
+#ifndef PNG_GAMMA_THRESHOLD
+#  define PNG_GAMMA_THRESHOLD 0.05
+#endif
+
+#endif /* PNG_INTERNAL */
+
+/* The following uses const char * instead of char * for error
+ * and warning message functions, so some compilers won't complain.
+ * If you do not want to use const, define PNG_NO_CONST here.
+ */
+
+#ifndef PNG_NO_CONST
+#  define PNG_CONST const
+#else
+#  define PNG_CONST
+#endif
+
+/* The following defines give you the ability to remove code from the
+ * library that you will not be using.  I wish I could figure out how to
+ * automate this, but I can't do that without making it seriously hard
+ * on the users.  So if you are not using an ability, change the #define
+ * to and #undef, and that part of the library will not be compiled.  If
+ * your linker can't find a function, you may want to make sure the
+ * ability is defined here.  Some of these depend upon some others being
+ * defined.  I haven't figured out all the interactions here, so you may
+ * have to experiment awhile to get everything to compile.  If you are
+ * creating or using a shared library, you probably shouldn't touch this,
+ * as it will affect the size of the structures, and this will cause bad
+ * things to happen if the library and/or application ever change.
+ */
+
+/* Any features you will not be using can be undef'ed here */
+
+/* GR-P, 0.96a: Set "*TRANSFORMS_SUPPORTED as default but allow user
+ * to turn it off with "*TRANSFORMS_NOT_SUPPORTED" or *PNG_NO_*_TRANSFORMS
+ * on the compile line, then pick and choose which ones to define without
+ * having to edit this file. It is safe to use the *TRANSFORMS_NOT_SUPPORTED
+ * if you only want to have a png-compliant reader/writer but don't need
+ * any of the extra transformations.  This saves about 80 kbytes in a
+ * typical installation of the library. (PNG_NO_* form added in version
+ * 1.0.1c, for consistency)
+ */
+
+/* The size of the png_text structure changed in libpng-1.0.6 when
+ * iTXt support was added.  iTXt support was turned off by default through
+ * libpng-1.2.x, to support old apps that malloc the png_text structure
+ * instead of calling png_set_text() and letting libpng malloc it.  It
+ * was turned on by default in libpng-1.3.0.
+ */
+
+#if defined(PNG_1_0_X) || defined (PNG_1_2_X)
+#  ifndef PNG_NO_iTXt_SUPPORTED
+#    define PNG_NO_iTXt_SUPPORTED
+#  endif
+#  ifndef PNG_NO_READ_iTXt
+#    define PNG_NO_READ_iTXt
+#  endif
+#  ifndef PNG_NO_WRITE_iTXt
+#    define PNG_NO_WRITE_iTXt
+#  endif
+#endif
+
+#if !defined(PNG_NO_iTXt_SUPPORTED)
+#  if !defined(PNG_READ_iTXt_SUPPORTED) && !defined(PNG_NO_READ_iTXt)
+#    define PNG_READ_iTXt
+#  endif
+#  if !defined(PNG_WRITE_iTXt_SUPPORTED) && !defined(PNG_NO_WRITE_iTXt)
+#    define PNG_WRITE_iTXt
+#  endif
+#endif
+
+/* The following support, added after version 1.0.0, can be turned off here en
+ * masse by defining PNG_LEGACY_SUPPORTED in case you need binary compatibility
+ * with old applications that require the length of png_struct and png_info
+ * to remain unchanged.
+ */
+
+#ifdef PNG_LEGACY_SUPPORTED
+#  define PNG_NO_FREE_ME
+#  define PNG_NO_READ_UNKNOWN_CHUNKS
+#  define PNG_NO_WRITE_UNKNOWN_CHUNKS
+#  define PNG_NO_READ_USER_CHUNKS
+#  define PNG_NO_READ_iCCP
+#  define PNG_NO_WRITE_iCCP
+#  define PNG_NO_READ_iTXt
+#  define PNG_NO_WRITE_iTXt
+#  define PNG_NO_READ_sCAL
+#  define PNG_NO_WRITE_sCAL
+#  define PNG_NO_READ_sPLT
+#  define PNG_NO_WRITE_sPLT
+#  define PNG_NO_INFO_IMAGE
+#  define PNG_NO_READ_RGB_TO_GRAY
+#  define PNG_NO_READ_USER_TRANSFORM
+#  define PNG_NO_WRITE_USER_TRANSFORM
+#  define PNG_NO_USER_MEM
+#  define PNG_NO_READ_EMPTY_PLTE
+#  define PNG_NO_MNG_FEATURES
+#  define PNG_NO_FIXED_POINT_SUPPORTED
+#endif
+
+/* Ignore attempt to turn off both floating and fixed point support */
+#if !defined(PNG_FLOATING_POINT_SUPPORTED) || \
+    !defined(PNG_NO_FIXED_POINT_SUPPORTED)
+#  define PNG_FIXED_POINT_SUPPORTED
+#endif
+
+#ifndef PNG_NO_FREE_ME
+#  define PNG_FREE_ME_SUPPORTED
+#endif
+
+#if defined(PNG_READ_SUPPORTED)
+
+#if !defined(PNG_READ_TRANSFORMS_NOT_SUPPORTED) && \
+      !defined(PNG_NO_READ_TRANSFORMS)
+#  define PNG_READ_TRANSFORMS_SUPPORTED
+#endif
+
+#ifdef PNG_READ_TRANSFORMS_SUPPORTED
+#  ifndef PNG_NO_READ_EXPAND
+#    define PNG_READ_EXPAND_SUPPORTED
+#  endif
+#  ifndef PNG_NO_READ_SHIFT
+#    define PNG_READ_SHIFT_SUPPORTED
+#  endif
+#  ifndef PNG_NO_READ_PACK
+#    define PNG_READ_PACK_SUPPORTED
+#  endif
+#  ifndef PNG_NO_READ_BGR
+#    define PNG_READ_BGR_SUPPORTED
+#  endif
+#  ifndef PNG_NO_READ_SWAP
+#    define PNG_READ_SWAP_SUPPORTED
+#  endif
+#  ifndef PNG_NO_READ_PACKSWAP
+#    define PNG_READ_PACKSWAP_SUPPORTED
+#  endif
+#  ifndef PNG_NO_READ_INVERT
+#    define PNG_READ_INVERT_SUPPORTED
+#  endif
+#  ifndef PNG_NO_READ_DITHER
+#    define PNG_READ_DITHER_SUPPORTED
+#  endif
+#  ifndef PNG_NO_READ_BACKGROUND
+#    define PNG_READ_BACKGROUND_SUPPORTED
+#  endif
+#  ifndef PNG_NO_READ_16_TO_8
+#    define PNG_READ_16_TO_8_SUPPORTED
+#  endif
+#  ifndef PNG_NO_READ_FILLER
+#    define PNG_READ_FILLER_SUPPORTED
+#  endif
+#  ifndef PNG_NO_READ_GAMMA
+#    define PNG_READ_GAMMA_SUPPORTED
+#  endif
+#  ifndef PNG_NO_READ_GRAY_TO_RGB
+#    define PNG_READ_GRAY_TO_RGB_SUPPORTED
+#  endif
+#  ifndef PNG_NO_READ_SWAP_ALPHA
+#    define PNG_READ_SWAP_ALPHA_SUPPORTED
+#  endif
+#  ifndef PNG_NO_READ_INVERT_ALPHA
+#    define PNG_READ_INVERT_ALPHA_SUPPORTED
+#  endif
+#  ifndef PNG_NO_READ_STRIP_ALPHA
+#    define PNG_READ_STRIP_ALPHA_SUPPORTED
+#  endif
+#  ifndef PNG_NO_READ_USER_TRANSFORM
+#    define PNG_READ_USER_TRANSFORM_SUPPORTED
+#  endif
+#  ifndef PNG_NO_READ_RGB_TO_GRAY
+#    define PNG_READ_RGB_TO_GRAY_SUPPORTED
+#  endif
+#endif /* PNG_READ_TRANSFORMS_SUPPORTED */
+
+#if !defined(PNG_NO_PROGRESSIVE_READ) && \
+ !defined(PNG_PROGRESSIVE_READ_NOT_SUPPORTED) /* if you don't do progressive */
+#  define PNG_PROGRESSIVE_READ_SUPPORTED    /* reading.  This is not talking */
+#endif                              /* about interlacing capability!  You'll */
+             /* still have interlacing unless you change the following line: */
+
+#define PNG_READ_INTERLACING_SUPPORTED /* required in PNG-compliant decoders */
+
+#ifndef PNG_NO_READ_COMPOSITE_NODIV
+#  ifndef PNG_NO_READ_COMPOSITED_NODIV  /* libpng-1.0.x misspelling */
+#    define PNG_READ_COMPOSITE_NODIV_SUPPORTED  /* well tested on Intel, SGI */
+#  endif
+#endif
+
+#if defined(PNG_1_0_X) || defined (PNG_1_2_X)
+/* Deprecated, will be removed from version 2.0.0.
+   Use PNG_MNG_FEATURES_SUPPORTED instead. */
+#ifndef PNG_NO_READ_EMPTY_PLTE
+#  define PNG_READ_EMPTY_PLTE_SUPPORTED
+#endif
+#endif
+
+#endif /* PNG_READ_SUPPORTED */
+
+#if defined(PNG_WRITE_SUPPORTED)
+
+# if !defined(PNG_WRITE_TRANSFORMS_NOT_SUPPORTED) && \
+    !defined(PNG_NO_WRITE_TRANSFORMS)
+#  define PNG_WRITE_TRANSFORMS_SUPPORTED
+#endif
+
+#ifdef PNG_WRITE_TRANSFORMS_SUPPORTED
+#  ifndef PNG_NO_WRITE_SHIFT
+#    define PNG_WRITE_SHIFT_SUPPORTED
+#  endif
+#  ifndef PNG_NO_WRITE_PACK
+#    define PNG_WRITE_PACK_SUPPORTED
+#  endif
+#  ifndef PNG_NO_WRITE_BGR
+#    define PNG_WRITE_BGR_SUPPORTED
+#  endif
+#  ifndef PNG_NO_WRITE_SWAP
+#    define PNG_WRITE_SWAP_SUPPORTED
+#  endif
+#  ifndef PNG_NO_WRITE_PACKSWAP
+#    define PNG_WRITE_PACKSWAP_SUPPORTED
+#  endif
+#  ifndef PNG_NO_WRITE_INVERT
+#    define PNG_WRITE_INVERT_SUPPORTED
+#  endif
+#  ifndef PNG_NO_WRITE_FILLER
+#    define PNG_WRITE_FILLER_SUPPORTED   /* same as WRITE_STRIP_ALPHA */
+#  endif
+#  ifndef PNG_NO_WRITE_SWAP_ALPHA
+#    define PNG_WRITE_SWAP_ALPHA_SUPPORTED
+#  endif
+#  ifndef PNG_NO_WRITE_INVERT_ALPHA
+#    define PNG_WRITE_INVERT_ALPHA_SUPPORTED
+#  endif
+#  ifndef PNG_NO_WRITE_USER_TRANSFORM
+#    define PNG_WRITE_USER_TRANSFORM_SUPPORTED
+#  endif
+#endif /* PNG_WRITE_TRANSFORMS_SUPPORTED */
+
+#if !defined(PNG_NO_WRITE_INTERLACING_SUPPORTED) && \
+    !defined(PNG_WRITE_INTERLACING_SUPPORTED)
+#define PNG_WRITE_INTERLACING_SUPPORTED  /* not required for PNG-compliant
+                                            encoders, but can cause trouble
+                                            if left undefined */
+#endif
+
+#if !defined(PNG_NO_WRITE_WEIGHTED_FILTER) && \
+    !defined(PNG_WRITE_WEIGHTED_FILTER) && \
+     defined(PNG_FLOATING_POINT_SUPPORTED)
+#  define PNG_WRITE_WEIGHTED_FILTER_SUPPORTED
+#endif
+
+#ifndef PNG_NO_WRITE_FLUSH
+#  define PNG_WRITE_FLUSH_SUPPORTED
+#endif
+
+#if defined(PNG_1_0_X) || defined (PNG_1_2_X)
+/* Deprecated, see PNG_MNG_FEATURES_SUPPORTED, above */
+#ifndef PNG_NO_WRITE_EMPTY_PLTE
+#  define PNG_WRITE_EMPTY_PLTE_SUPPORTED
+#endif
+#endif
+
+#endif /* PNG_WRITE_SUPPORTED */
+
+#ifndef PNG_1_0_X
+#  ifndef PNG_NO_ERROR_NUMBERS
+#    define PNG_ERROR_NUMBERS_SUPPORTED
+#  endif
+#endif /* PNG_1_0_X */
+
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
+    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
+#  ifndef PNG_NO_USER_TRANSFORM_PTR
+#    define PNG_USER_TRANSFORM_PTR_SUPPORTED
+#  endif
+#endif
+
+#ifndef PNG_NO_STDIO
+#  define PNG_TIME_RFC1123_SUPPORTED
+#endif
+
+/* This adds extra functions in pngget.c for accessing data from the
+ * info pointer (added in version 0.99)
+ * png_get_image_width()
+ * png_get_image_height()
+ * png_get_bit_depth()
+ * png_get_color_type()
+ * png_get_compression_type()
+ * png_get_filter_type()
+ * png_get_interlace_type()
+ * png_get_pixel_aspect_ratio()
+ * png_get_pixels_per_meter()
+ * png_get_x_offset_pixels()
+ * png_get_y_offset_pixels()
+ * png_get_x_offset_microns()
+ * png_get_y_offset_microns()
+ */
+#if !defined(PNG_NO_EASY_ACCESS) && !defined(PNG_EASY_ACCESS_SUPPORTED)
+#  define PNG_EASY_ACCESS_SUPPORTED
+#endif
+
+/* PNG_ASSEMBLER_CODE was enabled by default in version 1.2.0 
+ * even when PNG_USE_PNGVCRD or PNG_USE_PNGGCCRD is not defined.
+ *
+ * PNG_NO_ASSEMBLER_CODE disables use of all assembler code,
+ * and removes several functions from the API.
+ *
+ * PNG_NO_MMX_CODE disables the use of MMX code without changing the API.
+ * When MMX code is off, then optimized C replacement functions are used,
+ * if PNG_NO_OPTIMIZED_CODE is not enabled.  This was added in version
+ * 1.2.19.
+*/
+
+#if defined(PNG_READ_SUPPORTED) && !defined(PNG_NO_OPTIMIZED_CODE)
+#  ifndef PNG_OPTIMIZED_CODE_SUPPORTED
+#    define PNG_OPTIMIZED_CODE_SUPPORTED
+#  endif
+#endif
+
+#if defined(PNG_READ_SUPPORTED) && !defined(PNG_NO_ASSEMBLER_CODE)
+#  ifndef PNG_ASSEMBLER_CODE_SUPPORTED
+#    define PNG_ASSEMBLER_CODE_SUPPORTED
+#  endif
+
+#  if !defined(PNG_MMX_CODE_SUPPORTED) && !defined(PNG_NO_MMX_CODE)
+#    define PNG_MMX_CODE_SUPPORTED
+#  endif
+
+#  if !defined(PNG_USE_PNGVCRD) && defined(PNG_MMX_CODE_SUPPORTED) && \
+     defined(_MSC_VER)
+#    define PNG_USE_PNGVCRD
+#  endif
+
+#  if !defined(PNG_USE_PNGGCCRD) && defined(PNG_MMX_CODE_SUPPORTED) && \
+     !defined(PNG_USE_PNGVCRD)
+#    define PNG_USE_PNGGCCRD
+     /* If you are sure that you don't need thread safety and you are compiling
+        with PNG_USE_PNGCCRD for an MMX application, you can define this for
+        faster execution.  See pnggccrd.c.
+#    define PNG_THREAD_UNSAFE_OK
+     */
+#  endif
+
+#endif
+
+#if !defined(PNG_1_0_X)
+#if !defined(PNG_NO_USER_MEM) && !defined(PNG_USER_MEM_SUPPORTED)
+#  define PNG_USER_MEM_SUPPORTED
+#endif
+#endif /* PNG_1_0_X */
+
+/* Added at libpng-1.2.6 */
+#if !defined(PNG_1_0_X)
+#ifndef PNG_SET_USER_LIMITS_SUPPORTED
+#if !defined(PNG_NO_SET_USER_LIMITS) && !defined(PNG_SET_USER_LIMITS_SUPPORTED)
+#  define PNG_SET_USER_LIMITS_SUPPORTED
+#endif
+#endif
+#endif /* PNG_1_0_X */
+
+/* Added at libpng-1.0.16 and 1.2.6.  To accept all valid PNGS no matter
+ * how large, set these limits to 0x7fffffffL
+ */
+#ifndef PNG_USER_WIDTH_MAX
+#  define PNG_USER_WIDTH_MAX 1000000L
+#endif
+#ifndef PNG_USER_HEIGHT_MAX
+#  define PNG_USER_HEIGHT_MAX 1000000L
+#endif
+
+/* These are currently experimental features, define them if you want */
+
+/* very little testing */
+/*
+#ifdef PNG_READ_SUPPORTED
+#  ifndef PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
+#    define PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED
+#  endif
+#endif
+*/
+
+/* This is only for PowerPC big-endian and 680x0 systems */
+/* some testing */
+/*
+#ifndef PNG_READ_BIG_ENDIAN_SUPPORTED
+#  define PNG_READ_BIG_ENDIAN_SUPPORTED
+#endif
+*/
+
+/* Buggy compilers (e.g., gcc 2.7.2.2) need this */
+/*
+#define PNG_NO_POINTER_INDEXING
+*/
+
+/* These functions are turned off by default, as they will be phased out. */
+/*
+#define  PNG_USELESS_TESTS_SUPPORTED
+#define  PNG_CORRECT_PALETTE_SUPPORTED
+*/
+
+/* Any chunks you are not interested in, you can undef here.  The
+ * ones that allocate memory may be expecially important (hIST,
+ * tEXt, zTXt, tRNS, pCAL).  Others will just save time and make png_info
+ * a bit smaller.
+ */
+
+#if defined(PNG_READ_SUPPORTED) && \
+    !defined(PNG_READ_ANCILLARY_CHUNKS_NOT_SUPPORTED) && \
+    !defined(PNG_NO_READ_ANCILLARY_CHUNKS)
+#  define PNG_READ_ANCILLARY_CHUNKS_SUPPORTED
+#endif
+
+#if defined(PNG_WRITE_SUPPORTED) && \
+    !defined(PNG_WRITE_ANCILLARY_CHUNKS_NOT_SUPPORTED) && \
+    !defined(PNG_NO_WRITE_ANCILLARY_CHUNKS)
+#  define PNG_WRITE_ANCILLARY_CHUNKS_SUPPORTED
+#endif
+
+#ifdef PNG_READ_ANCILLARY_CHUNKS_SUPPORTED
+
+#ifdef PNG_NO_READ_TEXT
+#  define PNG_NO_READ_iTXt
+#  define PNG_NO_READ_tEXt
+#  define PNG_NO_READ_zTXt
+#endif
+#ifndef PNG_NO_READ_bKGD
+#  define PNG_READ_bKGD_SUPPORTED
+#  define PNG_bKGD_SUPPORTED
+#endif
+#ifndef PNG_NO_READ_cHRM
+#  define PNG_READ_cHRM_SUPPORTED
+#  define PNG_cHRM_SUPPORTED
+#endif
+#ifndef PNG_NO_READ_gAMA
+#  define PNG_READ_gAMA_SUPPORTED
+#  define PNG_gAMA_SUPPORTED
+#endif
+#ifndef PNG_NO_READ_hIST
+#  define PNG_READ_hIST_SUPPORTED
+#  define PNG_hIST_SUPPORTED
+#endif
+#ifndef PNG_NO_READ_iCCP
+#  define PNG_READ_iCCP_SUPPORTED
+#  define PNG_iCCP_SUPPORTED
+#endif
+#ifndef PNG_NO_READ_iTXt
+#  ifndef PNG_READ_iTXt_SUPPORTED
+#    define PNG_READ_iTXt_SUPPORTED
+#  endif
+#  ifndef PNG_iTXt_SUPPORTED
+#    define PNG_iTXt_SUPPORTED
+#  endif
+#endif
+#ifndef PNG_NO_READ_oFFs
+#  define PNG_READ_oFFs_SUPPORTED
+#  define PNG_oFFs_SUPPORTED
+#endif
+#ifndef PNG_NO_READ_pCAL
+#  define PNG_READ_pCAL_SUPPORTED
+#  define PNG_pCAL_SUPPORTED
+#endif
+#ifndef PNG_NO_READ_sCAL
+#  define PNG_READ_sCAL_SUPPORTED
+#  define PNG_sCAL_SUPPORTED
+#endif
+#ifndef PNG_NO_READ_pHYs
+#  define PNG_READ_pHYs_SUPPORTED
+#  define PNG_pHYs_SUPPORTED
+#endif
+#ifndef PNG_NO_READ_sBIT
+#  define PNG_READ_sBIT_SUPPORTED
+#  define PNG_sBIT_SUPPORTED
+#endif
+#ifndef PNG_NO_READ_sPLT
+#  define PNG_READ_sPLT_SUPPORTED
+#  define PNG_sPLT_SUPPORTED
+#endif
+#ifndef PNG_NO_READ_sRGB
+#  define PNG_READ_sRGB_SUPPORTED
+#  define PNG_sRGB_SUPPORTED
+#endif
+#ifndef PNG_NO_READ_tEXt
+#  define PNG_READ_tEXt_SUPPORTED
+#  define PNG_tEXt_SUPPORTED
+#endif
+#ifndef PNG_NO_READ_tIME
+#  define PNG_READ_tIME_SUPPORTED
+#  define PNG_tIME_SUPPORTED
+#endif
+#ifndef PNG_NO_READ_tRNS
+#  define PNG_READ_tRNS_SUPPORTED
+#  define PNG_tRNS_SUPPORTED
+#endif
+#ifndef PNG_NO_READ_zTXt
+#  define PNG_READ_zTXt_SUPPORTED
+#  define PNG_zTXt_SUPPORTED
+#endif
+#ifndef PNG_NO_READ_UNKNOWN_CHUNKS
+#  define PNG_READ_UNKNOWN_CHUNKS_SUPPORTED
+#  ifndef PNG_UNKNOWN_CHUNKS_SUPPORTED
+#    define PNG_UNKNOWN_CHUNKS_SUPPORTED
+#  endif
+#  ifndef PNG_NO_HANDLE_AS_UNKNOWN
+#    define PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+#  endif
+#endif
+#if !defined(PNG_NO_READ_USER_CHUNKS) && \
+     defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
+#  define PNG_READ_USER_CHUNKS_SUPPORTED
+#  define PNG_USER_CHUNKS_SUPPORTED
+#  ifdef PNG_NO_READ_UNKNOWN_CHUNKS
+#    undef PNG_NO_READ_UNKNOWN_CHUNKS
+#  endif
+#  ifdef PNG_NO_HANDLE_AS_UNKNOWN
+#    undef PNG_NO_HANDLE_AS_UNKNOWN
+#  endif
+#endif
+#ifndef PNG_NO_READ_OPT_PLTE
+#  define PNG_READ_OPT_PLTE_SUPPORTED /* only affects support of the */
+#endif                      /* optional PLTE chunk in RGB and RGBA images */
+#if defined(PNG_READ_iTXt_SUPPORTED) || defined(PNG_READ_tEXt_SUPPORTED) || \
+    defined(PNG_READ_zTXt_SUPPORTED)
+#  define PNG_READ_TEXT_SUPPORTED
+#  define PNG_TEXT_SUPPORTED
+#endif
+
+#endif /* PNG_READ_ANCILLARY_CHUNKS_SUPPORTED */
+
+#ifdef PNG_WRITE_ANCILLARY_CHUNKS_SUPPORTED
+
+#ifdef PNG_NO_WRITE_TEXT
+#  define PNG_NO_WRITE_iTXt
+#  define PNG_NO_WRITE_tEXt
+#  define PNG_NO_WRITE_zTXt
+#endif
+#ifndef PNG_NO_WRITE_bKGD
+#  define PNG_WRITE_bKGD_SUPPORTED
+#  ifndef PNG_bKGD_SUPPORTED
+#    define PNG_bKGD_SUPPORTED
+#  endif
+#endif
+#ifndef PNG_NO_WRITE_cHRM
+#  define PNG_WRITE_cHRM_SUPPORTED
+#  ifndef PNG_cHRM_SUPPORTED
+#    define PNG_cHRM_SUPPORTED
+#  endif
+#endif
+#ifndef PNG_NO_WRITE_gAMA
+#  define PNG_WRITE_gAMA_SUPPORTED
+#  ifndef PNG_gAMA_SUPPORTED
+#    define PNG_gAMA_SUPPORTED
+#  endif
+#endif
+#ifndef PNG_NO_WRITE_hIST
+#  define PNG_WRITE_hIST_SUPPORTED
+#  ifndef PNG_hIST_SUPPORTED
+#    define PNG_hIST_SUPPORTED
+#  endif
+#endif
+#ifndef PNG_NO_WRITE_iCCP
+#  define PNG_WRITE_iCCP_SUPPORTED
+#  ifndef PNG_iCCP_SUPPORTED
+#    define PNG_iCCP_SUPPORTED
+#  endif
+#endif
+#ifndef PNG_NO_WRITE_iTXt
+#  ifndef PNG_WRITE_iTXt_SUPPORTED
+#    define PNG_WRITE_iTXt_SUPPORTED
+#  endif
+#  ifndef PNG_iTXt_SUPPORTED
+#    define PNG_iTXt_SUPPORTED
+#  endif
+#endif
+#ifndef PNG_NO_WRITE_oFFs
+#  define PNG_WRITE_oFFs_SUPPORTED
+#  ifndef PNG_oFFs_SUPPORTED
+#    define PNG_oFFs_SUPPORTED
+#  endif
+#endif
+#ifndef PNG_NO_WRITE_pCAL
+#  define PNG_WRITE_pCAL_SUPPORTED
+#  ifndef PNG_pCAL_SUPPORTED
+#    define PNG_pCAL_SUPPORTED
+#  endif
+#endif
+#ifndef PNG_NO_WRITE_sCAL
+#  define PNG_WRITE_sCAL_SUPPORTED
+#  ifndef PNG_sCAL_SUPPORTED
+#    define PNG_sCAL_SUPPORTED
+#  endif
+#endif
+#ifndef PNG_NO_WRITE_pHYs
+#  define PNG_WRITE_pHYs_SUPPORTED
+#  ifndef PNG_pHYs_SUPPORTED
+#    define PNG_pHYs_SUPPORTED
+#  endif
+#endif
+#ifndef PNG_NO_WRITE_sBIT
+#  define PNG_WRITE_sBIT_SUPPORTED
+#  ifndef PNG_sBIT_SUPPORTED
+#    define PNG_sBIT_SUPPORTED
+#  endif
+#endif
+#ifndef PNG_NO_WRITE_sPLT
+#  define PNG_WRITE_sPLT_SUPPORTED
+#  ifndef PNG_sPLT_SUPPORTED
+#    define PNG_sPLT_SUPPORTED
+#  endif
+#endif
+#ifndef PNG_NO_WRITE_sRGB
+#  define PNG_WRITE_sRGB_SUPPORTED
+#  ifndef PNG_sRGB_SUPPORTED
+#    define PNG_sRGB_SUPPORTED
+#  endif
+#endif
+#ifndef PNG_NO_WRITE_tEXt
+#  define PNG_WRITE_tEXt_SUPPORTED
+#  ifndef PNG_tEXt_SUPPORTED
+#    define PNG_tEXt_SUPPORTED
+#  endif
+#endif
+#ifndef PNG_NO_WRITE_tIME
+#  define PNG_WRITE_tIME_SUPPORTED
+#  ifndef PNG_tIME_SUPPORTED
+#    define PNG_tIME_SUPPORTED
+#  endif
+#endif
+#ifndef PNG_NO_WRITE_tRNS
+#  define PNG_WRITE_tRNS_SUPPORTED
+#  ifndef PNG_tRNS_SUPPORTED
+#    define PNG_tRNS_SUPPORTED
+#  endif
+#endif
+#ifndef PNG_NO_WRITE_zTXt
+#  define PNG_WRITE_zTXt_SUPPORTED
+#  ifndef PNG_zTXt_SUPPORTED
+#    define PNG_zTXt_SUPPORTED
+#  endif
+#endif
+#ifndef PNG_NO_WRITE_UNKNOWN_CHUNKS
+#  define PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED
+#  ifndef PNG_UNKNOWN_CHUNKS_SUPPORTED
+#    define PNG_UNKNOWN_CHUNKS_SUPPORTED
+#  endif
+#  ifndef PNG_NO_HANDLE_AS_UNKNOWN
+#     ifndef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+#       define PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+#     endif
+#  endif
+#endif
+#if defined(PNG_WRITE_iTXt_SUPPORTED) || defined(PNG_WRITE_tEXt_SUPPORTED) || \
+    defined(PNG_WRITE_zTXt_SUPPORTED)
+#  define PNG_WRITE_TEXT_SUPPORTED
+#  ifndef PNG_TEXT_SUPPORTED
+#    define PNG_TEXT_SUPPORTED
+#  endif
+#endif
+
+#endif /* PNG_WRITE_ANCILLARY_CHUNKS_SUPPORTED */
+
+/* Turn this off to disable png_read_png() and
+ * png_write_png() and leave the row_pointers member
+ * out of the info structure.
+ */
+#ifndef PNG_NO_INFO_IMAGE
+#  define PNG_INFO_IMAGE_SUPPORTED
+#endif
+
+/* need the time information for reading tIME chunks */
+#if defined(PNG_tIME_SUPPORTED)
+#  if !defined(_WIN32_WCE)
+     /* "time.h" functions are not supported on WindowsCE */
+#    include <time.h>
+#  endif
+#endif
+
+/* Some typedefs to get us started.  These should be safe on most of the
+ * common platforms.  The typedefs should be at least as large as the
+ * numbers suggest (a png_uint_32 must be at least 32 bits long), but they
+ * don't have to be exactly that size.  Some compilers dislike passing
+ * unsigned shorts as function parameters, so you may be better off using
+ * unsigned int for png_uint_16.  Likewise, for 64-bit systems, you may
+ * want to have unsigned int for png_uint_32 instead of unsigned long.
+ */
+
+typedef unsigned long png_uint_32;
+typedef long png_int_32;
+typedef unsigned short png_uint_16;
+typedef short png_int_16;
+typedef unsigned char png_byte;
+
+/* This is usually size_t.  It is typedef'ed just in case you need it to
+   change (I'm not sure if you will or not, so I thought I'd be safe) */
+#ifdef PNG_SIZE_T
+   typedef PNG_SIZE_T png_size_t;
+#  define png_sizeof(x) png_convert_size(sizeof (x))
+#else
+   typedef size_t png_size_t;
+#  define png_sizeof(x) sizeof (x)
+#endif
+
+/* The following is needed for medium model support.  It cannot be in the
+ * PNG_INTERNAL section.  Needs modification for other compilers besides
+ * MSC.  Model independent support declares all arrays and pointers to be
+ * large using the far keyword.  The zlib version used must also support
+ * model independent data.  As of version zlib 1.0.4, the necessary changes
+ * have been made in zlib.  The USE_FAR_KEYWORD define triggers other
+ * changes that are needed. (Tim Wegner)
+ */
+
+/* Separate compiler dependencies (problem here is that zlib.h always
+   defines FAR. (SJT) */
+#ifdef __BORLANDC__
+#  if defined(__LARGE__) || defined(__HUGE__) || defined(__COMPACT__)
+#    define LDATA 1
+#  else
+#    define LDATA 0
+#  endif
+   /* GRR:  why is Cygwin in here?  Cygwin is not Borland C... */
+#  if !defined(__WIN32__) && !defined(__FLAT__) && !defined(__CYGWIN__)
+#    define PNG_MAX_MALLOC_64K
+#    if (LDATA != 1)
+#      ifndef FAR
+#        define FAR __far
+#      endif
+#      define USE_FAR_KEYWORD
+#    endif   /* LDATA != 1 */
+     /* Possibly useful for moving data out of default segment.
+      * Uncomment it if you want. Could also define FARDATA as
+      * const if your compiler supports it. (SJT)
+#    define FARDATA FAR
+      */
+#  endif  /* __WIN32__, __FLAT__, __CYGWIN__ */
+#endif   /* __BORLANDC__ */
+
+
+/* Suggest testing for specific compiler first before testing for
+ * FAR.  The Watcom compiler defines both __MEDIUM__ and M_I86MM,
+ * making reliance oncertain keywords suspect. (SJT)
+ */
+
+/* MSC Medium model */
+#if defined(FAR)
+#  if defined(M_I86MM)
+#    define USE_FAR_KEYWORD
+#    define FARDATA FAR
+#    include <dos.h>
+#  endif
+#endif
+
+/* SJT: default case */
+#ifndef FAR
+#  define FAR
+#endif
+
+/* At this point FAR is always defined */
+#ifndef FARDATA
+#  define FARDATA
+#endif
+
+/* Typedef for floating-point numbers that are converted
+   to fixed-point with a multiple of 100,000, e.g., int_gamma */
+typedef png_int_32 png_fixed_point;
+
+/* Add typedefs for pointers */
+typedef void            FAR * png_voidp;
+typedef png_byte        FAR * png_bytep;
+typedef png_uint_32     FAR * png_uint_32p;
+typedef png_int_32      FAR * png_int_32p;
+typedef png_uint_16     FAR * png_uint_16p;
+typedef png_int_16      FAR * png_int_16p;
+typedef PNG_CONST char  FAR * png_const_charp;
+typedef char            FAR * png_charp;
+typedef png_fixed_point FAR * png_fixed_point_p;
+
+#ifndef PNG_NO_STDIO
+#if defined(_WIN32_WCE)
+typedef HANDLE                png_FILE_p;
+#else
+typedef FILE                * png_FILE_p;
+#endif
+#endif
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+typedef double          FAR * png_doublep;
+#endif
+
+/* Pointers to pointers; i.e. arrays */
+typedef png_byte        FAR * FAR * png_bytepp;
+typedef png_uint_32     FAR * FAR * png_uint_32pp;
+typedef png_int_32      FAR * FAR * png_int_32pp;
+typedef png_uint_16     FAR * FAR * png_uint_16pp;
+typedef png_int_16      FAR * FAR * png_int_16pp;
+typedef PNG_CONST char  FAR * FAR * png_const_charpp;
+typedef char            FAR * FAR * png_charpp;
+typedef png_fixed_point FAR * FAR * png_fixed_point_pp;
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+typedef double          FAR * FAR * png_doublepp;
+#endif
+
+/* Pointers to pointers to pointers; i.e., pointer to array */
+typedef char            FAR * FAR * FAR * png_charppp;
+
+#if defined(PNG_1_0_X) || defined(PNG_1_2_X)
+/* SPC -  Is this stuff deprecated? */
+/* It'll be removed as of libpng-1.3.0 - GR-P */
+/* libpng typedefs for types in zlib. If zlib changes
+ * or another compression library is used, then change these.
+ * Eliminates need to change all the source files.
+ */
+typedef charf *         png_zcharp;
+typedef charf * FAR *   png_zcharpp;
+typedef z_stream FAR *  png_zstreamp;
+#endif /* (PNG_1_0_X) || defined(PNG_1_2_X) */
+
+/*
+ * Define PNG_BUILD_DLL if the module being built is a Windows
+ * LIBPNG DLL.
+ *
+ * Define PNG_USE_DLL if you want to *link* to the Windows LIBPNG DLL.
+ * It is equivalent to Microsoft predefined macro _DLL that is
+ * automatically defined when you compile using the share
+ * version of the CRT (C Run-Time library)
+ *
+ * The cygwin mods make this behavior a little different:
+ * Define PNG_BUILD_DLL if you are building a dll for use with cygwin
+ * Define PNG_STATIC if you are building a static library for use with cygwin,
+ *   -or- if you are building an application that you want to link to the
+ *   static library.
+ * PNG_USE_DLL is defined by default (no user action needed) unless one of
+ *   the other flags is defined.
+ */
+
+#if !defined(PNG_DLL) && (defined(PNG_BUILD_DLL) || defined(PNG_USE_DLL))
+#  define PNG_DLL
+#endif
+/* If CYGWIN, then disallow GLOBAL ARRAYS unless building a static lib.
+ * When building a static lib, default to no GLOBAL ARRAYS, but allow
+ * command-line override
+ */
+#if defined(__CYGWIN__)
+#  if !defined(PNG_STATIC)
+#    if defined(PNG_USE_GLOBAL_ARRAYS)
+#      undef PNG_USE_GLOBAL_ARRAYS
+#    endif
+#    if !defined(PNG_USE_LOCAL_ARRAYS)
+#      define PNG_USE_LOCAL_ARRAYS
+#    endif
+#  else
+#    if defined(PNG_USE_LOCAL_ARRAYS) || defined(PNG_NO_GLOBAL_ARRAYS)
+#      if defined(PNG_USE_GLOBAL_ARRAYS)
+#        undef PNG_USE_GLOBAL_ARRAYS
+#      endif
+#    endif
+#  endif
+#  if !defined(PNG_USE_LOCAL_ARRAYS) && !defined(PNG_USE_GLOBAL_ARRAYS)
+#    define PNG_USE_LOCAL_ARRAYS
+#  endif
+#endif
+
+/* Do not use global arrays (helps with building DLL's)
+ * They are no longer used in libpng itself, since version 1.0.5c,
+ * but might be required for some pre-1.0.5c applications.
+ */
+#if !defined(PNG_USE_LOCAL_ARRAYS) && !defined(PNG_USE_GLOBAL_ARRAYS)
+#  if defined(PNG_NO_GLOBAL_ARRAYS) || \
+      (defined(__GNUC__) && defined(PNG_DLL)) || defined(_MSC_VER)
+#    define PNG_USE_LOCAL_ARRAYS
+#  else
+#    define PNG_USE_GLOBAL_ARRAYS
+#  endif
+#endif
+
+#if defined(__CYGWIN__)
+#  undef PNGAPI
+#  define PNGAPI __cdecl
+#  undef PNG_IMPEXP
+#  define PNG_IMPEXP
+#endif  
+
+/* If you define PNGAPI, e.g., with compiler option "-DPNGAPI=__stdcall",
+ * you may get warnings regarding the linkage of png_zalloc and png_zfree.
+ * Don't ignore those warnings; you must also reset the default calling
+ * convention in your compiler to match your PNGAPI, and you must build
+ * zlib and your applications the same way you build libpng.
+ */
+
+#if defined(__MINGW32__) && !defined(PNG_MODULEDEF)
+#  ifndef PNG_NO_MODULEDEF
+#    define PNG_NO_MODULEDEF
+#  endif
+#endif
+
+#if !defined(PNG_IMPEXP) && defined(PNG_BUILD_DLL) && !defined(PNG_NO_MODULEDEF)
+#  define PNG_IMPEXP
+#endif
+
+#if defined(PNG_DLL) || defined(_DLL) || defined(__DLL__ ) || \
+    (( defined(_Windows) || defined(_WINDOWS) || \
+       defined(WIN32) || defined(_WIN32) || defined(__WIN32__) ))
+
+#  ifndef PNGAPI
+#     if defined(__GNUC__) || (defined (_MSC_VER) && (_MSC_VER >= 800))
+#        define PNGAPI __cdecl
+#     else
+#        define PNGAPI _cdecl
+#     endif
+#  endif
+
+#  if !defined(PNG_IMPEXP) && (!defined(PNG_DLL) || \
+       0 /* WINCOMPILER_WITH_NO_SUPPORT_FOR_DECLIMPEXP */)
+#     define PNG_IMPEXP
+#  endif
+
+#  if !defined(PNG_IMPEXP)
+
+#     define PNG_EXPORT_TYPE1(type,symbol)  PNG_IMPEXP type PNGAPI symbol
+#     define PNG_EXPORT_TYPE2(type,symbol)  type PNG_IMPEXP PNGAPI symbol
+
+      /* Borland/Microsoft */
+#     if defined(_MSC_VER) || defined(__BORLANDC__)
+#        if (_MSC_VER >= 800) || (__BORLANDC__ >= 0x500)
+#           define PNG_EXPORT PNG_EXPORT_TYPE1
+#        else
+#           define PNG_EXPORT PNG_EXPORT_TYPE2
+#           if defined(PNG_BUILD_DLL)
+#              define PNG_IMPEXP __export
+#           else
+#              define PNG_IMPEXP /*__import */ /* doesn't exist AFAIK in
+                                                 VC++ */
+#           endif                             /* Exists in Borland C++ for
+                                                 C++ classes (== huge) */
+#        endif
+#     endif
+
+#     if !defined(PNG_IMPEXP)
+#        if defined(PNG_BUILD_DLL)
+#           define PNG_IMPEXP __declspec(dllexport)
+#        else
+#           define PNG_IMPEXP __declspec(dllimport)
+#        endif
+#     endif
+#  endif  /* PNG_IMPEXP */
+#else /* !(DLL || non-cygwin WINDOWS) */
+#   if (defined(__IBMC__) || defined(__IBMCPP__)) && defined(__OS2__)
+#      ifndef PNGAPI
+#         define PNGAPI _System
+#      endif
+#   else
+#      if 0 /* ... other platforms, with other meanings */
+#      endif
+#   endif
+#endif
+
+#ifndef PNGAPI
+#  define PNGAPI
+#endif
+#ifndef PNG_IMPEXP
+#  define PNG_IMPEXP
+#endif
+
+#ifdef PNG_BUILDSYMS
+#  ifndef PNG_EXPORT
+#    define PNG_EXPORT(type,symbol) PNG_FUNCTION_EXPORT symbol END
+#  endif
+#  ifdef PNG_USE_GLOBAL_ARRAYS
+#    ifndef PNG_EXPORT_VAR
+#      define PNG_EXPORT_VAR(type) PNG_DATA_EXPORT
+#    endif
+#  endif
+#endif
+
+#ifndef PNG_EXPORT
+#  define PNG_EXPORT(type,symbol) PNG_IMPEXP type PNGAPI symbol
+#endif
+
+#ifdef PNG_USE_GLOBAL_ARRAYS
+#  ifndef PNG_EXPORT_VAR
+#    define PNG_EXPORT_VAR(type) extern PNG_IMPEXP type
+#  endif
+#endif
+
+/* User may want to use these so they are not in PNG_INTERNAL. Any library
+ * functions that are passed far data must be model independent.
+ */
+
+#ifndef PNG_ABORT
+#  define PNG_ABORT() abort()
+#endif
+
+#ifdef PNG_SETJMP_SUPPORTED
+#  define png_jmpbuf(png_ptr) ((png_ptr)->jmpbuf)
+#else
+#  define png_jmpbuf(png_ptr) \
+   (LIBPNG_WAS_COMPILED_WITH__PNG_SETJMP_NOT_SUPPORTED)
+#endif
+
+#if defined(USE_FAR_KEYWORD)  /* memory model independent fns */
+/* use this to make far-to-near assignments */
+#  define CHECK   1
+#  define NOCHECK 0
+#  define CVT_PTR(ptr) (png_far_to_near(png_ptr,ptr,CHECK))
+#  define CVT_PTR_NOCHECK(ptr) (png_far_to_near(png_ptr,ptr,NOCHECK))
+#  define png_snprintf _fsnprintf   /* Added to v 1.2.19 */
+#  define png_strcpy  _fstrcpy
+#  define png_strncpy _fstrncpy   /* Added to v 1.2.6 */
+#  define png_strlen  _fstrlen
+#  define png_memcmp  _fmemcmp    /* SJT: added */
+#  define png_memcpy  _fmemcpy
+#  define png_memset  _fmemset
+#else /* use the usual functions */
+#  define CVT_PTR(ptr)         (ptr)
+#  define CVT_PTR_NOCHECK(ptr) (ptr)
+#  ifndef PNG_NO_SNPRINTF
+#    ifdef _MSC_VER
+#      define png_snprintf _snprintf   /* Added to v 1.2.19 */
+#      define png_snprintf2 _snprintf
+#      define png_snprintf6 _snprintf
+#    else
+#      define png_snprintf snprintf   /* Added to v 1.2.19 */
+#      define png_snprintf2 snprintf
+#      define png_snprintf6 snprintf
+#    endif
+#  else
+     /* You don't have or don't want to use snprintf().  Caution: Using
+      * sprintf instead of snprintf exposes your application to accidental
+      * or malevolent buffer overflows.  If you don't have snprintf()
+      * as a general rule you should provide one (you can get one from
+      * Portable OpenSSH). */
+#    define png_snprintf(s1,n,fmt,x1) sprintf(s1,fmt,x1)
+#    define png_snprintf2(s1,n,fmt,x1,x2) sprintf(s1,fmt,x1,x2)
+#    define png_snprintf6(s1,n,fmt,x1,x2,x3,x4,x5,x6) \
+        sprintf(s1,fmt,x1,x2,x3,x4,x5,x6)
+#  endif
+#  define png_strcpy  strcpy
+#  define png_strncpy strncpy     /* Added to v 1.2.6 */
+#  define png_strlen  strlen
+#  define png_memcmp  memcmp      /* SJT: added */
+#  define png_memcpy  memcpy
+#  define png_memset  memset
+#endif
+/* End of memory model independent support */
+
+/* Just a little check that someone hasn't tried to define something
+ * contradictory.
+ */
+#if (PNG_ZBUF_SIZE > 65536L) && defined(PNG_MAX_MALLOC_64K)
+#  undef PNG_ZBUF_SIZE
+#  define PNG_ZBUF_SIZE 65536L
+#endif
+
+#ifdef PNG_READ_SUPPORTED
+/* Prior to libpng-1.0.9, this block was in pngasmrd.h */
+#if defined(PNG_INTERNAL)
+
+#if defined(PNG_USE_PNGGCCRD) || defined(PNG_USE_PNGVCRD)
+  /* Platform must be Pentium.  Makefile must assemble and load
+   * pnggccrd.c or  pngvcrd.c. MMX will be detected at run time and
+   * used if present.
+   */
+#  ifndef PNG_NO_MMX_COMBINE_ROW
+#    define PNG_HAVE_MMX_COMBINE_ROW
+#  endif
+#  ifndef PNG_NO_MMX_READ_INTERLACE
+#    define PNG_HAVE_MMX_READ_INTERLACE
+#  endif
+#  ifndef PNG_NO_MMX_READ_FILTER_ROW
+#    define PNG_HAVE_MMX_READ_FILTER_ROW
+#    ifndef PNG_NO_MMX_FILTER_SUB
+#      define PNG_MMX_READ_FILTER_SUB_SUPPORTED
+#    endif
+#    if !(defined(__GNUC__) && defined(__x86_64__) && (__GNUC__ < 4))
+       /* work around 64-bit gcc compiler bugs in gcc-3.x */
+#      ifndef PNG_NO_MMX_FILTER_UP
+#        define PNG_MMX_READ_FILTER_UP_SUPPORTED
+#      endif
+#      ifndef PNG_NO_MMX_FILTER_AVG
+#        define PNG_MMX_READ_FILTER_AVG_SUPPORTED
+#      endif
+#      ifndef PNG_NO_MMX_FILTER_PAETH
+#        define PNG_MMX_READ_FILTER_PAETH_SUPPORTED
+#      endif
+#    endif /* !((__x86_64__) && (GNUC < 4)) */
+#  endif
+  /* These are the default thresholds before the MMX code kicks in; if either
+   * rowbytes or bitdepth is below the threshold, plain C code is used.  These
+   * can be overridden at runtime via the png_set_mmx_thresholds() call in
+   * libpng 1.2.0 and later.  The values below were chosen by Intel.
+   */
+#  ifndef PNG_MMX_ROWBYTES_THRESHOLD_DEFAULT
+#    define PNG_MMX_ROWBYTES_THRESHOLD_DEFAULT  128  /*  >=  */
+#  endif
+#  ifndef PNG_MMX_BITDEPTH_THRESHOLD_DEFAULT
+#    define PNG_MMX_BITDEPTH_THRESHOLD_DEFAULT  9    /*  >=  */   
+#  endif
+#endif /* PNG_USE_PNGGCCRD || PNG_USE_PNGVCRD */
+/* - see pngvcrd.c or pnggccrd.c for info about what is currently enabled */
+
+#endif /* PNG_INTERNAL */
+#endif /* PNG_READ_SUPPORTED */
+
+/* Added at libpng-1.2.8 */
+#endif /* PNG_VERSION_INFO_ONLY */
+
+#endif /* PNGCONF_H */
diff --git a/distrib/libpng-1.2.19/pngerror.c b/distrib/libpng-1.2.19/pngerror.c
new file mode 100644
index 0000000..b1d5fbe
--- /dev/null
+++ b/distrib/libpng-1.2.19/pngerror.c
@@ -0,0 +1,326 @@
+
+/* pngerror.c - stub functions for i/o and memory allocation
+ *
+ * Last changed in libpng 1.2.19 August 18, 2007
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1998-2007 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This file provides a location for all error handling.  Users who
+ * need special error handling are expected to write replacement functions
+ * and use png_set_error_fn() to use those functions.  See the instructions
+ * at each function.
+ */
+
+#define PNG_INTERNAL
+#include "png.h"
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+static void /* PRIVATE */
+png_default_error PNGARG((png_structp png_ptr,
+  png_const_charp error_message));
+#ifndef PNG_NO_WARNINGS
+static void /* PRIVATE */
+png_default_warning PNGARG((png_structp png_ptr,
+  png_const_charp warning_message));
+#endif /* PNG_NO_WARNINGS */
+
+/* This function is called whenever there is a fatal error.  This function
+ * should not be changed.  If there is a need to handle errors differently,
+ * you should supply a replacement error function and use png_set_error_fn()
+ * to replace the error function at run-time.
+ */
+void PNGAPI
+png_error(png_structp png_ptr, png_const_charp error_message)
+{
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+   char msg[16];
+   if (png_ptr != NULL)
+   {
+     if (png_ptr->flags&
+       (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))
+     {
+       if (*error_message == '#')
+       {
+           int offset;
+           for (offset=1; offset<15; offset++)
+              if (*(error_message+offset) == ' ')
+                  break;
+           if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT)
+           {
+              int i;
+              for (i=0; i<offset-1; i++)
+                 msg[i]=error_message[i+1];
+              msg[i]='\0';
+              error_message=msg;
+           }
+           else
+              error_message+=offset;
+       }
+       else
+       {
+           if (png_ptr->flags&PNG_FLAG_STRIP_ERROR_TEXT)
+           {
+              msg[0]='0';
+              msg[1]='\0';
+              error_message=msg;
+           }
+       }
+     }
+   }
+#endif
+   if (png_ptr != NULL && png_ptr->error_fn != NULL)
+      (*(png_ptr->error_fn))(png_ptr, error_message);
+
+   /* If the custom handler doesn't exist, or if it returns,
+      use the default handler, which will not return. */
+   png_default_error(png_ptr, error_message);
+}
+
+#ifndef PNG_NO_WARNINGS
+/* This function is called whenever there is a non-fatal error.  This function
+ * should not be changed.  If there is a need to handle warnings differently,
+ * you should supply a replacement warning function and use
+ * png_set_error_fn() to replace the warning function at run-time.
+ */
+void PNGAPI
+png_warning(png_structp png_ptr, png_const_charp warning_message)
+{
+   int offset = 0;
+   if (png_ptr != NULL)
+   {
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+   if (png_ptr->flags&
+     (PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))
+#endif
+     {
+       if (*warning_message == '#')
+       {
+           for (offset=1; offset<15; offset++)
+              if (*(warning_message+offset) == ' ')
+                  break;
+       }
+     }
+     if (png_ptr != NULL && png_ptr->warning_fn != NULL)
+        (*(png_ptr->warning_fn))(png_ptr, warning_message+offset);
+   }
+   else
+      png_default_warning(png_ptr, warning_message+offset);
+}
+#endif /* PNG_NO_WARNINGS */
+
+
+/* These utilities are used internally to build an error message that relates
+ * to the current chunk.  The chunk name comes from png_ptr->chunk_name,
+ * this is used to prefix the message.  The message is limited in length
+ * to 63 bytes, the name characters are output as hex digits wrapped in []
+ * if the character is invalid.
+ */
+#define isnonalpha(c) ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
+static PNG_CONST char png_digit[16] = {
+   '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
+   'A', 'B', 'C', 'D', 'E', 'F'
+};
+
+static void /* PRIVATE */
+png_format_buffer(png_structp png_ptr, png_charp buffer, png_const_charp
+   error_message)
+{
+   int iout = 0, iin = 0;
+
+   while (iin < 4)
+   {
+      int c = png_ptr->chunk_name[iin++];
+      if (isnonalpha(c))
+      {
+         buffer[iout++] = '[';
+         buffer[iout++] = png_digit[(c & 0xf0) >> 4];
+         buffer[iout++] = png_digit[c & 0x0f];
+         buffer[iout++] = ']';
+      }
+      else
+      {
+         buffer[iout++] = (png_byte)c;
+      }
+   }
+
+   if (error_message == NULL)
+      buffer[iout] = 0;
+   else
+   {
+      buffer[iout++] = ':';
+      buffer[iout++] = ' ';
+      png_strncpy(buffer+iout, error_message, 63);
+      buffer[iout+63] = 0;
+   }
+}
+
+#ifdef PNG_READ_SUPPORTED
+void PNGAPI
+png_chunk_error(png_structp png_ptr, png_const_charp error_message)
+{
+   char msg[18+64];
+   if (png_ptr == NULL)
+     png_error(png_ptr, error_message);
+   else
+   {
+     png_format_buffer(png_ptr, msg, error_message);
+     png_error(png_ptr, msg);
+   }
+}
+
+#ifndef PNG_NO_WARNINGS
+void PNGAPI
+png_chunk_warning(png_structp png_ptr, png_const_charp warning_message)
+{
+   char msg[18+64];
+   if (png_ptr == NULL)
+     png_warning(png_ptr, warning_message);
+   else
+   {
+     png_format_buffer(png_ptr, msg, warning_message);
+     png_warning(png_ptr, msg);
+   }
+}
+#endif /* PNG_NO_WARNINGS */
+
+#endif /* PNG_READ_SUPPORTED */
+
+/* This is the default error handling function.  Note that replacements for
+ * this function MUST NOT RETURN, or the program will likely crash.  This
+ * function is used by default, or if the program supplies NULL for the
+ * error function pointer in png_set_error_fn().
+ */
+static void /* PRIVATE */
+png_default_error(png_structp png_ptr, png_const_charp error_message)
+{
+#ifndef PNG_NO_CONSOLE_IO
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+   if (*error_message == '#')
+   {
+     int offset;
+     char error_number[16];
+     for (offset=0; offset<15; offset++)
+     {
+         error_number[offset] = *(error_message+offset+1);
+         if (*(error_message+offset) == ' ')
+             break;
+     }
+     if((offset > 1) && (offset < 15))
+     {
+       error_number[offset-1]='\0';
+       fprintf(stderr, "libpng error no. %s: %s\n", error_number,
+          error_message+offset);
+     }
+     else
+       fprintf(stderr, "libpng error: %s, offset=%d\n", error_message,offset);
+   }
+   else
+#endif
+   fprintf(stderr, "libpng error: %s\n", error_message);
+#endif
+
+#ifdef PNG_SETJMP_SUPPORTED
+   if (png_ptr)
+   {
+#  ifdef USE_FAR_KEYWORD
+   {
+      jmp_buf jmpbuf;
+      png_memcpy(jmpbuf, png_ptr->jmpbuf, png_sizeof(jmp_buf));
+      longjmp(jmpbuf, 1);
+   }
+#  else
+   longjmp(png_ptr->jmpbuf, 1);
+#  endif
+   }
+#else
+   PNG_ABORT();
+#endif
+#ifdef PNG_NO_CONSOLE_IO
+   error_message = error_message; /* make compiler happy */
+#endif
+}
+
+#ifndef PNG_NO_WARNINGS
+/* This function is called when there is a warning, but the library thinks
+ * it can continue anyway.  Replacement functions don't have to do anything
+ * here if you don't want them to.  In the default configuration, png_ptr is
+ * not used, but it is passed in case it may be useful.
+ */
+static void /* PRIVATE */
+png_default_warning(png_structp png_ptr, png_const_charp warning_message)
+{
+#ifndef PNG_NO_CONSOLE_IO
+#  ifdef PNG_ERROR_NUMBERS_SUPPORTED
+   if (*warning_message == '#')
+   {
+     int offset;
+     char warning_number[16];
+     for (offset=0; offset<15; offset++)
+     {
+        warning_number[offset]=*(warning_message+offset+1);
+        if (*(warning_message+offset) == ' ')
+            break;
+     }
+     if((offset > 1) && (offset < 15))
+     {
+       warning_number[offset-1]='\0';
+       fprintf(stderr, "libpng warning no. %s: %s\n", warning_number,
+          warning_message+offset);
+     }
+     else
+       fprintf(stderr, "libpng warning: %s\n", warning_message);
+   }
+   else
+#  endif
+     fprintf(stderr, "libpng warning: %s\n", warning_message);
+#else
+   warning_message = warning_message; /* make compiler happy */
+#endif
+   png_ptr = png_ptr; /* make compiler happy */
+}
+#endif /* PNG_NO_WARNINGS */
+
+/* This function is called when the application wants to use another method
+ * of handling errors and warnings.  Note that the error function MUST NOT
+ * return to the calling routine or serious problems will occur.  The return
+ * method used in the default routine calls longjmp(png_ptr->jmpbuf, 1)
+ */
+void PNGAPI
+png_set_error_fn(png_structp png_ptr, png_voidp error_ptr,
+   png_error_ptr error_fn, png_error_ptr warning_fn)
+{
+   if (png_ptr == NULL)
+      return;
+   png_ptr->error_ptr = error_ptr;
+   png_ptr->error_fn = error_fn;
+   png_ptr->warning_fn = warning_fn;
+}
+
+
+/* This function returns a pointer to the error_ptr associated with the user
+ * functions.  The application should free any memory associated with this
+ * pointer before png_write_destroy and png_read_destroy are called.
+ */
+png_voidp PNGAPI
+png_get_error_ptr(png_structp png_ptr)
+{
+   if (png_ptr == NULL)
+      return NULL;
+   return ((png_voidp)png_ptr->error_ptr);
+}
+
+
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+void PNGAPI
+png_set_strip_error_numbers(png_structp png_ptr, png_uint_32 strip_mode)
+{
+   if(png_ptr != NULL)
+   {
+     png_ptr->flags &=
+       ((~(PNG_FLAG_STRIP_ERROR_NUMBERS|PNG_FLAG_STRIP_ERROR_TEXT))&strip_mode);
+   }
+}
+#endif
+#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
diff --git a/distrib/libpng-1.2.19/pnggccrd.c b/distrib/libpng-1.2.19/pnggccrd.c
new file mode 100644
index 0000000..f63867c
--- /dev/null
+++ b/distrib/libpng-1.2.19/pnggccrd.c
@@ -0,0 +1,6041 @@
+
+/* pnggccrd.c - mixed C/assembler version of utilities to read a PNG file
+ *
+ * For Intel/AMD x86 or x86-64 CPU (Pentium-MMX or later) and GNU C compiler.
+ *
+ * Last changed in libpng 1.2.19 August 18, 2007
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1998 Intel Corporation
+ * Copyright (c) 1999-2002,2007 Greg Roelofs
+ * Copyright (c) 1998-2007 Glenn Randers-Pehrson
+ *
+ * Based on MSVC code contributed by Nirav Chhatrapati, Intel Corp., 1998.
+ * Interface to libpng contributed by Gilles Vollant, 1999.
+ * GNU C port by Greg Roelofs, 1999-2001.
+ *
+ * References:
+ *
+ *     http://www.intel.com/drg/pentiumII/appnotes/916/916.htm
+ *     http://www.intel.com/drg/pentiumII/appnotes/923/923.htm
+ *       [Intel's performance analysis of the MMX vs. non-MMX code;
+ *        moved/deleted as of 2006, but text and some graphs still
+ *        available via WayBack Machine at archive.org]
+ *
+ *     http://www.ibiblio.org/gferg/ldp/GCC-Inline-Assembly-HOWTO.html
+ *     http://sam.zoy.org/blog/2007-04-13-shlib-with-non-pic-code-have-inline-assembly-and-pic-mix-well
+ *     http://gcc.gnu.org/onlinedocs/gcc/Extended-Asm.html
+ *     http://gcc.gnu.org/onlinedocs/gcc/Variable-Attributes.html
+ *     http://gcc.gnu.org/onlinedocs/gcc/Function-Attributes.html
+ *     AMD64 Architecture Programmer's Manual, volumes 1 and 5
+ *       [http://www.amd.com/us-en/Processors/TechnicalResources/0,,30_182_739_7044,00.html]
+ *     Intel 64 and IA-32 Software Developer's Manuals
+ *       [http://developer.intel.com/products/processor/manuals/]
+ *
+ * png_read_filter_row_mmx_*() were converted in place with intel2gas 1.3.1:
+ *
+ *     intel2gas -mdI pnggccrd.c.partially-msvc -o pnggccrd.c
+ *
+ * and then cleaned up by hand.  See http://hermes.terminal.at/intel2gas/ .
+ *
+ * NOTE:  A sufficiently recent version of GNU as (or as.exe under DOS/Windows)
+ * is required to assemble the newer asm instructions such as movq.  (Version
+ * 2.5.2l.15 is definitely too old.)  See ftp://ftp.gnu.org/pub/gnu/binutils/ .
+ */
+
+/*
+ * PORTING NOTES AND CHANGELOG (mostly by Greg Roelofs)
+ * ===========================
+ *
+ * 19991006:
+ *  - fixed sign error in post-MMX cleanup code (16- & 32-bit cases)
+ *
+ * 19991007:
+ *  - additional optimizations (possible or definite):
+ *     x [DONE] write MMX code for 64-bit case (pixel_bytes == 8) [not tested]
+ *     - write MMX code for 48-bit case (pixel_bytes == 6)
+ *     - figure out what's up with 24-bit case (pixel_bytes == 3):
+ *        why subtract 8 from width_mmx in the pass 4/5 case?
+ *        (only width_mmx case) (near line 2335)
+ *     x [DONE] replace pixel_bytes within each block with the true
+ *        constant value (or are compilers smart enough to do that?)
+ *     - rewrite all MMX interlacing code so it's aligned with
+ *        the *beginning* of the row buffer, not the end.  This
+ *        would not only allow one to eliminate half of the memory
+ *        writes for odd passes (that is, pass == odd), it may also
+ *        eliminate some unaligned-data-access exceptions (assuming
+ *        there's a penalty for not aligning 64-bit accesses on
+ *        64-bit boundaries).  The only catch is that the "leftover"
+ *        pixel(s) at the end of the row would have to be saved,
+ *        but there are enough unused MMX registers in every case,
+ *        so this is not a problem.  A further benefit is that the
+ *        post-MMX cleanup code (C code) in at least some of the
+ *        cases could be done within the assembler block.
+ *  x [DONE] the "v3 v2 v1 v0 v7 v6 v5 v4" comments are confusing,
+ *     inconsistent, and don't match the MMX Programmer's Reference
+ *     Manual conventions anyway.  They should be changed to
+ *     "b7 b6 b5 b4 b3 b2 b1 b0," where b0 indicates the byte that
+ *     was lowest in memory (i.e., corresponding to a left pixel)
+ *     and b7 is the byte that was highest (i.e., a right pixel).
+ *
+ * 19991016:
+ *  - Brennan's Guide notwithstanding, gcc under Linux does *not*
+ *     want globals prefixed by underscores when referencing them--
+ *     i.e., if the variable is const4, then refer to it as const4,
+ *     not _const4.  This seems to be a djgpp-specific requirement.
+ *     Also, such variables apparently *must* be declared outside
+ *     of functions; neither static nor automatic variables work if
+ *     defined within the scope of a single function, but both
+ *     static and truly global (multi-module) variables work fine.
+ *
+ * 19991017:
+ *  - replaced pixel_bytes in each png_memcpy() call with constant value for
+ *     inlining (png_do_read_interlace() "non-MMX/modified C code" block)
+ *
+ * 19991023:
+ *  - fixed png_combine_row() non-MMX replication bug (odd passes only?)
+ *  - switched from string-concatenation-with-macros to cleaner method of
+ *     renaming global variables for djgpp--i.e., always use prefixes in
+ *     inlined assembler code (== strings) and conditionally rename the
+ *     variables, not the other way around.  Hence _const4, _mask8_0, etc.
+ *
+ * 19991024:
+ *  - fixed mmxsupport()/png_do_read_interlace() first-row bug
+ *     This one was severely weird:  even though mmxsupport() doesn't touch
+ *     ebx (where "row" pointer was stored), it nevertheless managed to zero
+ *     the register (even in static/non-fPIC code--see below), which in turn
+ *     caused png_do_read_interlace() to return prematurely on the first row of
+ *     interlaced images (i.e., without expanding the interlaced pixels).
+ *     Inspection of the generated assembly code didn't turn up any clues,
+ *     although it did point at a minor optimization (i.e., get rid of
+ *     mmx_supported_local variable and just use eax).  Possibly the CPUID
+ *     instruction is more destructive than it looks?  (Not yet checked.)
+ *  - "info gcc" was next to useless, so compared fPIC and non-fPIC assembly
+ *     listings...  Apparently register spillage has to do with ebx, since
+ *     it's used to index the global offset table.  Commenting it out of the
+ *     input-reg lists in png_combine_row() eliminated compiler barfage, so
+ *     ifdef'd with __PIC__ macro:  if defined, use a global for unmask
+ *
+ * 19991107:
+ *  - verified CPUID clobberage:  12-char string constant ("GenuineIntel",
+ *     "AuthenticAMD", etc.) placed in ebx:ecx:edx.  Still need to polish.
+ *
+ * 19991120:
+ *  - made "diff" variable (now "_dif") global to simplify conversion of
+ *     filtering routines (running out of regs, sigh).  "diff" is still used
+ *     in interlacing routines, however.
+ *  - fixed up both versions of mmxsupport() (ORIG_THAT_USED_TO_CLOBBER_EBX
+ *     macro determines which is used); original not yet tested.
+ *
+ * 20000213:
+ *  - when compiling with gcc, be sure to use  -fomit-frame-pointer
+ *
+ * 20000319:
+ *  - fixed a register-name typo in png_do_read_interlace(), default (MMX) case,
+ *     pass == 4 or 5, that caused visible corruption of interlaced images
+ *
+ * 20000623:
+ *  - Various problems were reported with gcc 2.95.2 in the Cygwin environment,
+ *     many of the form "forbidden register 0 (ax) was spilled for class AREG."
+ *     This is explained at http://gcc.gnu.org/fom_serv/cache/23.html, and
+ *     Chuck Wilson supplied a patch involving dummy output registers.  See
+ *     http://sourceforge.net/bugs/?func=detailbug&bug_id=108741&group_id=5624
+ *     for the original (anonymous) SourceForge bug report.
+ *
+ * 20000706:
+ *  - Chuck Wilson passed along these remaining gcc 2.95.2 errors:
+ *       pnggccrd.c: In function `png_combine_row':
+ *       pnggccrd.c:525: more than 10 operands in `asm'
+ *       pnggccrd.c:669: more than 10 operands in `asm'
+ *       pnggccrd.c:828: more than 10 operands in `asm'
+ *       pnggccrd.c:994: more than 10 operands in `asm'
+ *       pnggccrd.c:1177: more than 10 operands in `asm'
+ *     They are all the same problem and can be worked around by using the
+ *     global _unmask variable unconditionally, not just in the -fPIC case.
+ *     Reportedly earlier versions of gcc also have the problem with more than
+ *     10 operands; they just don't report it.  Much strangeness ensues, etc.
+ *
+ * 20000729:
+ *  - enabled png_read_filter_row_mmx_up() (shortest remaining unconverted
+ *     MMX routine); began converting png_read_filter_row_mmx_sub()
+ *  - to finish remaining sections:
+ *     - clean up indentation and comments
+ *     - preload local variables
+ *     - add output and input regs (order of former determines numerical
+ *        mapping of latter)
+ *     - avoid all usage of ebx (including bx, bh, bl) register [20000823]
+ *     - remove "$" from addressing of Shift and Mask variables [20000823]
+ *
+ * 20000731:
+ *  - global union vars causing segfaults in png_read_filter_row_mmx_sub()?
+ *
+ * 20000822:
+ *  - ARGH, stupid png_read_filter_row_mmx_sub() segfault only happens with
+ *     shared-library (-fPIC) version!  Code works just fine as part of static
+ *     library.  Should have tested that sooner.
+ *     ebx is getting clobbered again (explicitly this time); need to save it
+ *     on stack or rewrite asm code to avoid using it altogether.  Blargh!
+ *
+ * 20000823:
+ *  - first section was trickiest; all remaining sections have ebx -> edx now.
+ *     (-fPIC works again.)  Also added missing underscores to various Shift*
+ *     and *Mask* globals and got rid of leading "$" signs.
+ *
+ * 20000826:
+ *  - added visual separators to help navigate microscopic printed copies
+ *     (http://pobox.com/~newt/code/gpr-latest.zip, mode 10); started working
+ *     on png_read_filter_row_mmx_avg()
+ *
+ * 20000828:
+ *  - finished png_read_filter_row_mmx_avg():  only Paeth left! (930 lines...)
+ *     What the hell, did png_read_filter_row_mmx_paeth(), too.  Comments not
+ *     cleaned up/shortened in either routine, but functionality is complete
+ *     and seems to be working fine.
+ *
+ * 20000829:
+ *  - ahhh, figured out last(?) bit of gcc/gas asm-fu:  if register is listed
+ *     as an input reg (with dummy output variables, etc.), then it *cannot*
+ *     also appear in the clobber list or gcc 2.95.2 will barf.  The solution
+ *     is simple enough...
+ *
+ * 20000914:
+ *  - bug in png_read_filter_row_mmx_avg():  16-bit grayscale not handled
+ *     correctly (but 48-bit RGB just fine)
+ *
+ * 20000916:
+ *  - fixed bug in png_read_filter_row_mmx_avg(), bpp == 2 case; three errors:
+ *     - "_ShiftBpp.use = 24;"      should have been   "_ShiftBpp.use = 16;"
+ *     - "_ShiftRem.use = 40;"      should have been   "_ShiftRem.use = 48;"
+ *     - "psllq _ShiftRem, %%mm2"   should have been   "psrlq _ShiftRem, %%mm2"
+ *
+ * 20010101:
+ *  - added new png_init_mmx_flags() function (here only because it needs to
+ *     call mmxsupport(), which should probably become global png_mmxsupport());
+ *     modified other MMX routines to run conditionally (png_ptr->asm_flags)
+ *
+ * 20010103:
+ *  - renamed mmxsupport() to png_mmx_support(), with auto-set of mmx_supported,
+ *     and made it public; moved png_init_mmx_flags() to png.c as internal func
+ *
+ * 20010104:
+ *  - removed dependency on png_read_filter_row_c() (C code already duplicated
+ *     within MMX version of png_read_filter_row()) so no longer necessary to
+ *     compile it into pngrutil.o
+ *
+ * 20010310:
+ *  - fixed buffer-overrun bug in png_combine_row() C code (non-MMX)
+ *
+ * 20010808:
+ *  - added PNG_THREAD_UNSAFE_OK around code using global variables [GR-P]
+ *
+ * 20011124:
+ *  - fixed missing save of Eflag in png_mmx_support() [Maxim Sobolev]
+ *
+ * 20020304:
+ *  - eliminated incorrect use of width_mmx in pixel_bytes == 8 case
+ *
+ * 20020407:
+ *  - fixed insufficient preservation of ebx register [Sami Farin]
+ *
+ * 20040724:
+ *  - more tinkering with clobber list at lines 4529 and 5033 to get it to
+ *     compile with gcc 3.4 [GR-P]
+ *
+ * 20040809:
+ *  - added "rim" definitions for CONST4 and CONST6 [GR-P]
+ *
+ * 20060303:
+ *  - added "OS2" to list of systems that don't need leading underscores [GR-P]
+ *
+ * 20060320:
+ *  - made PIC-compliant [Christian Aichinger]
+ *
+ * 20070313:
+ *  - finally applied Giuseppe Ghibò's 64-bit patch of 20060803 (completely
+ *     overlooked Dylan Alex Simon's similar patch of 20060414, oops...)
+ *
+ * 20070524:
+ *  - fixed link failure caused by asm-only variables being optimized out
+ *     (identified by Dimitri of Trolltech) with __attribute__((used)), which
+ *     also gets rid of warnings => nuked ugly png_squelch_warnings() hack
+ *  - dropped redundant ifdef
+ *  - moved png_mmx_support() back up where originally intended (as in
+ *     pngvcrd.c), using __attribute__((noinline)) in extra prototype
+ *
+ * 20070527:
+ *  - revised png_combine_row() to reuse mask in lieu of external _unmask
+ *  - moved 32-bit (RGBA) case to top of png_combine_row():  most common
+ *  - just about ready to give up on x86-64 -fPIC mode; can't even access 16
+ *     _mask*_* constants without triggering link error on shared library:
+ *       /usr/bin/ld: pnggccrd.pic.o: relocation R_X86_64_32S against `a local
+ *         symbol' can not be used when making a shared object; recompile with
+ *         -fPIC
+ *       pnggccrd.pic.o: could not read symbols: Bad value
+ *       ("objdump -x pnggccrd.pic.o | grep rodata" to verify)
+ *     [might be able to work around by doing within assembly code whatever
+ *     -fPIC does, but given problems to date, seems like long shot...]
+ *     [relevant ifdefs:  __x86_64__ && __PIC__ => C code only]
+ *  - changed #if 0 to #ifdef PNG_CLOBBER_MMX_REGS_SUPPORTED in case gcc ever
+ *     supports MMX regs (%mm0, etc.) in clobber list (not supported by gcc
+ *     2.7.2.3, 2.91.66 (egcs 1.1.2), 3.x, or 4.1.2)
+ *
+ * 20070603:
+ *  - revised png_combine_row() to use @GOTPCREL(%%rip) addressing on _c64
+ *     struct of _mask*_* constants for x86-64 -fPIC; see sam.zoy.org link
+ *     above for details
+ *  - moved _const4 and _const6 into _c64 struct, renamed to _amask5_3_0 and
+ *     _amask7_1_0, respectively
+ *  - can't figure out how to use _c64._mask*_* vars within asm code, so still
+ *     need single variables for non-x86-64/-fPIC half :-(
+ *  - replaced various __PIC__ ifdefs with *_GOT_ebx macros
+ *  - moved _LBCarryMask and _HBClearMask into _c64 struct
+ *  - conditionally replaced _p*temp variables with %r11d-%r13d (via p*_TEMP
+ *     and CLOBBER_r1*d macros)
+ *
+ * 20070604:
+ *  - replaced all _ActiveMask and _ActiveMaskEnd with new _amask*_*_* consts
+ *     (_amask naming convention:  numbers of 00-bytes, ff-bytes, 00-bytes)
+ *    - _ActiveMask     // (10) // avg/paeth/sub; read-only; consts; movq/pand
+ *       0x0000000000ffffffLL (bpp 3, avg)      _amask5_3_0
+ *       0xffffffffffffffffLL (bpp 4, 6, avg)   _amask0_8_0
+ *       0x000000000000ffffLL (bpp 2, avg)      _amask6_2_0
+ *       0x0000000000ffffffLL (bpp 3, paeth)    _amask5_3_0
+ *       0x00000000ffffffffLL (bpp 6, paeth)    _amask4_4_0
+ *       0x00000000ffffffffLL (bpp 4, paeth)    _amask4_4_0
+ *       0x00000000ffffffffLL (bpp 8, paeth)    _amask4_4_0
+ *       0x0000ffffff000000LL (bpp 3, sub)      _amask2_3_3
+ *       0x00000000ffff0000LL (bpp 2, sub)      _amask4_2_2
+ *    - _ActiveMaskEnd  // (1)  // paeth only; read-only; const; pand
+ *       0xffff000000000000LL (bpp 3, paeth)    _amask0_2_6
+ *  - changed all "#if defined(__x86_64__) // later // && defined(__PIC__)"
+ *     lines to "#ifdef PNG_x86_64_USE_GOTPCREL" for easier/safer testing
+ *
+ * 20070605:
+ *  - merged PNG_x86_64_USE_GOTPCREL, non-PNG_x86_64_USE_GOTPCREL code via
+ *     *MASK* and LOAD/RESTORE macros
+ *
+ * 20070607:
+ *  - replaced all constant instances of _ShiftBpp, _ShiftRem with immediates
+ *     (still have two shared cases in avg, sub routines)
+ *
+ * 20070609:
+ *  - replaced remaining instances of _ShiftBpp, _ShiftRem with immediates
+ *     (split sub and avg 4/6-bpp cases into separate blocks)
+ *  - fixed paeth bug due to clobbered r11/r12/r13 regs
+ *
+ * 20070610:
+ *  - made global "_dif" variable (avg/paeth/sub routines) local again (now
+ *     "diff"--see 19991120 entry above), using register constraints
+ *  - note that %ebp in clobber list doesn't actually work, at least for 32-bit
+ *     version and gcc 4.1.2; must save and restore manually.  (Seems to work
+ *     OK for 64-bit version and gcc 3.4.3, but gcc may not be using ebp/rbp
+ *     in that case.)
+ *  - started replacing direct _MMXLength accesses with register constraints
+ *
+ * 20070612:
+ *  - continued replacing direct _MMXLength accesses with register constraints
+ *
+ * 20070613:
+ *  - finished replacing direct _MMXLength accesses with register constraints;
+ *     switched to local variable (and renamed back to MMXLength)
+ *
+ * 20070614:
+ *  - fixed sub bpp = 1 bug
+ *  - started replacing direct _FullLength accesses with register constraints
+ *
+ * 20070615:
+ *  - fixed 64-bit paeth bpp 3 crash bug (misplaced LOAD_GOT_rbp)
+ *  - fixed 64-bit paeth bpp 1/2 and cleanup-block crash bugs (misplaced
+ *     RESTORE_r11_r12_r13)
+ *  - slightly optimized avg/paeth cleanup blocks and paeth bpp 1/2 block
+ *     (save/restore ebx only if needed)
+ *  - continued replacing direct _FullLength accesses with register constraints
+ *
+ * 20070616:
+ *  - finished replacing direct _FullLength accesses with register constraints
+ *     (*ugly* conditional clobber-separator macros for avg and paeth, sigh)
+ *
+ * 20070618:
+ *  - fixed misplaced PNG_THREAD_UNSAFE_OK endif (was missing LOAD_GOT_rbp/
+ *     RESTORE_rbp in 32-bit thread-safe case)
+ *  - changed all "ifdef *" to "if defined(*)" [GR-P]
+ *
+ * 20070619:
+ *  - rearranged most bitdepth-related case statements to put most frequent
+ *     cases at top (24-bit, 32-bit, 8-bit, rest)
+ *
+ * 20070623:
+ *  - cleaned up png_debug() warnings/formatting
+ *  - removed PNG_MMX_CODE_SUPPORTED ifdefs and added outer __GNUC__ ifdef
+ *     (module no longer used by non-x86/non-GCC builds as of libpng 1.2.19)
+ *  - removed single libpng-1.2.x PNG_DEBUG dependency on 1.0.x png_struct
+ *     member (row_buf_size)
+ *  - rearranged pass-related if-blocks in png_do_read_interlace() to put most
+ *     frequent cases (4, 5) at top [GR-P suggestion]
+ *
+ * 20070624-29:
+ *  - fixed 64-bit crash bug:  pointers -> rsi/rdi, not esi/edi (switched to
+ *     %0/%1/%2/%3/%4 notation; eliminated size suffixes from relevant add/
+ *     inc/sub/mov instructions; changed dummy vars to pointers)
+ *     - png_combine_row()
+ *     - png_do_read_interlace()
+ *     - png_read_filter_row_mmx_avg()
+ *     - png_read_filter_row_mmx_paeth()
+ *     - png_read_filter_row_mmx_sub()
+ *     - png_read_filter_row_mmx_up()
+ *  - NOTE:  this fix makes use of the fact that modifying a 32-bit reg (e.g.,
+ *     %%ebx) clears the top half of its corresponding 64-bit reg (%%rbx), so
+ *     it's safe to mix 32-bit operations with 64-bit base/index addressing
+ *     (see new PSI/PAX/PBX/PDX/PBP/etc. "pointer-register" macros); applies
+ *     also to clobber lists
+ *
+ * 20070630:
+ *  - cleaned up formatting, macros, minor png_read_filter_row_mmx_sub() 8-bpp
+ *     register-usage inefficiency
+ *  - fixed 32-bit png_do_read_interlace() bug (was using pointer size for
+ *     64-bit dummy values)
+ *
+ * 20070703:
+ *  - added check for (manual) PIC macro to fix OpenBSD crash bug
+ *
+ * 20070717:
+ *  - fixed 48-bit png_combine_row() bug (was acting like 32-bit):  copy 6
+ *     bytes per pixel, not 4, and use stride of 6, not 4, in the second loop
+ *     of interlace processing of 48-bit pixels [GR-P]
+ *
+ * 20070722:
+ *  - fixed 64-bit png_uint_32 bug with MMXLength/FullLength temp vars
+ *
+ * [still broken:  tops of all row-filter blocks (input/output constraints);
+ *  shows up on 64-bit dynamic (-fPIC) version with -O2, especially if debug-
+ *  printfs enabled, but at right edge of odd-width images even if disabled]
+ *
+ *
+ * STILL TO DO:
+ *  - fix final thread-unsafe code using stack vars and pointer? (paeth top,
+ *     default, bottom only:  default, bottom already 5 reg constraints; could
+ *     replace bpp with pointer and group bpp/patemp/pbtemp/pctemp in array)
+ *  - fix ebp/no-reg-constraint inefficiency (avg/paeth/sub top)
+ *  - test png_do_read_interlace() 64-bit case (pixel_bytes == 8)
+ *  - write MMX code for 48-bit case (pixel_bytes == 6)
+ *  - figure out what's up with 24-bit case (pixel_bytes == 3):
+ *     why subtract 8 from width_mmx in the pass 4/5 case?  due to
+ *     odd number of bytes? (only width_mmx case) (near line 2335)
+ *  - rewrite all MMX interlacing code so it's aligned with beginning
+ *     of the row buffer, not the end (see 19991007 for details)
+ *  - add error messages to any remaining bogus default cases
+ *  - enable pixel_depth == 8 cases in png_read_filter_row()? (test speed)
+ *  - try =r, etc., as reg constraints?  (would gcc use 64-bit ones on x86-64?)
+ *  - need full, non-graphical, CRC-based test suite...  maybe autogenerate
+ *     random data of various height/width/depth, compute CRCs, write (C
+ *     funcs), read (asm/MMX), recompute CRCs, and compare?
+ *  - write true x86-64 version using 128-bit "media instructions", %xmm0-15,
+ *     and extra general-purpose registers
+ */
+
+#if defined(__GNUC__)
+
+#define PNG_INTERNAL
+#include "png.h"
+
+
+/* for some inexplicable reason, gcc 3.3.5 on OpenBSD (and elsewhere?) does
+ * *not* define __PIC__ when the -fPIC option is used, so we have to rely on
+ * makefiles and whatnot to define the PIC macro explicitly */
+#if defined(PIC) && !defined(__PIC__)   // (this can/should move to pngconf.h)
+#  define __PIC__
+#endif
+
+#if defined(PNG_ASSEMBLER_CODE_SUPPORTED) && defined(PNG_USE_PNGGCCRD)
+
+/* if you want/need full thread-safety on x86-64 even when linking statically,
+ * comment out the "&& defined(__PIC__)" part here: */
+#if defined(__x86_64__) && defined(__PIC__)
+#  define PNG_x86_64_USE_GOTPCREL            // GOTPCREL => full thread-safety
+#  define PNG_CLOBBER_x86_64_REGS_SUPPORTED  // works as of gcc 3.4.3 ...
+#endif
+
+int PNGAPI png_mmx_support(void);
+
+#if defined(PNG_USE_LOCAL_ARRAYS)
+static PNG_CONST int FARDATA png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+static PNG_CONST int FARDATA png_pass_inc[7]   = {8, 8, 4, 4, 2, 2, 1};
+static PNG_CONST int FARDATA png_pass_width[7] = {8, 4, 4, 2, 2, 1, 1};
+#endif
+
+/* djgpp, Win32, Cygwin, and OS2 add their own underscores to global variables,
+ * so define them without: */
+#if defined(__DJGPP__) || defined(WIN32) || defined(__CYGWIN__) || \
+    defined(__OS2__)
+#  define _mmx_supported  mmx_supported
+#  define _mask8_0        mask8_0
+#  define _mask16_1       mask16_1
+#  define _mask16_0       mask16_0
+#  define _mask24_2       mask24_2
+#  define _mask24_1       mask24_1
+#  define _mask24_0       mask24_0
+#  define _mask32_3       mask32_3
+#  define _mask32_2       mask32_2
+#  define _mask32_1       mask32_1
+#  define _mask32_0       mask32_0
+#  define _mask48_5       mask48_5
+#  define _mask48_4       mask48_4
+#  define _mask48_3       mask48_3
+#  define _mask48_2       mask48_2
+#  define _mask48_1       mask48_1
+#  define _mask48_0       mask48_0
+#  define _amask5_3_0     amask5_3_0
+#  define _amask7_1_0     amask7_1_0
+#  define _LBCarryMask    LBCarryMask
+#  define _HBClearMask    HBClearMask
+#  define _amask0_8_0     amask0_8_0
+#  define _amask6_2_0     amask6_2_0
+#  define _amask4_4_0     amask4_4_0
+#  define _amask0_2_6     amask0_2_6
+#  define _amask2_3_3     amask2_3_3
+#  define _amask4_2_2     amask4_2_2
+#  if defined(PNG_THREAD_UNSAFE_OK)
+#    define _patemp       patemp
+#    define _pbtemp       pbtemp
+#    define _pctemp       pctemp
+#  endif
+#endif // djgpp, Win32, Cygwin, OS2
+
+
+/* These constants are used in the inlined MMX assembly code. */
+
+typedef unsigned long long  ull;
+
+#if defined(PNG_x86_64_USE_GOTPCREL)
+static PNG_CONST struct {
+    //ull _mask_array[26];
+
+    // png_combine_row() constants:
+    ull _mask8_0;
+    ull _mask16_0, _mask16_1;
+    ull _mask24_0, _mask24_1, _mask24_2;
+    ull _mask32_0, _mask32_1, _mask32_2, _mask32_3;
+    ull _mask48_0, _mask48_1, _mask48_2, _mask48_3, _mask48_4, _mask48_5;
+
+    // png_do_read_interlace() constants:
+    ull _amask5_3_0, _amask7_1_0;  // was _const4 and _const6, respectively
+
+    // png_read_filter_row_mmx_avg() constants (also uses _amask5_3_0):
+    ull _LBCarryMask, _HBClearMask;
+    ull _amask0_8_0, _amask6_2_0;  // was ActiveMask for bpp 4/6 and 2 cases
+
+    // png_read_filter_row_mmx_paeth() constants (also uses _amask5_3_0):
+    ull _amask4_4_0, _amask0_2_6;  // was ActiveMask{,End} for bpp 6/4/8 and 3
+
+    // png_read_filter_row_mmx_sub() constants:
+    ull _amask2_3_3, _amask4_2_2;  // was ActiveMask for bpp 3 and 2 cases
+
+} _c64 __attribute__((used, aligned(8))) = {
+
+    // png_combine_row() constants:
+    0x0102040810204080LL, // _mask8_0      offset 0
+
+    0x1010202040408080LL, // _mask16_0     offset 8
+    0x0101020204040808LL, // _mask16_1     offset 16
+
+    0x2020404040808080LL, // _mask24_0     offset 24
+    0x0408080810101020LL, // _mask24_1     offset 32
+    0x0101010202020404LL, // _mask24_2     offset 40
+
+    0x4040404080808080LL, // _mask32_0     offset 48
+    0x1010101020202020LL, // _mask32_1     offset 56
+    0x0404040408080808LL, // _mask32_2     offset 64
+    0x0101010102020202LL, // _mask32_3     offset 72
+
+    0x4040808080808080LL, // _mask48_0     offset 80
+    0x2020202040404040LL, // _mask48_1     offset 88
+    0x1010101010102020LL, // _mask48_2     offset 96
+    0x0404080808080808LL, // _mask48_3     offset 104
+    0x0202020204040404LL, // _mask48_4     offset 112
+    0x0101010101010202LL, // _mask48_5     offset 120
+
+    // png_do_read_interlace() constants:
+    0x0000000000FFFFFFLL, // _amask5_3_0   offset 128  (bpp 3, avg/paeth) const4
+    0x00000000000000FFLL, // _amask7_1_0   offset 136                     const6
+
+    // png_read_filter_row_mmx_avg() constants:
+    0x0101010101010101LL, // _LBCarryMask  offset 144
+    0x7F7F7F7F7F7F7F7FLL, // _HBClearMask  offset 152
+    0xFFFFFFFFFFFFFFFFLL, // _amask0_8_0   offset 160  (bpp 4/6, avg)
+    0x000000000000FFFFLL, // _amask6_2_0   offset 168  (bpp 2,   avg)
+
+    // png_read_filter_row_mmx_paeth() constants:
+    0x00000000FFFFFFFFLL, // _amask4_4_0   offset 176  (bpp 6/4/8, paeth)
+    0xFFFF000000000000LL, // _amask0_2_6   offset 184  (bpp 3, paeth)   A.M.End
+
+    // png_read_filter_row_mmx_sub() constants:
+    0x0000FFFFFF000000LL, // _amask2_3_3   offset 192  (bpp 3, sub)
+    0x00000000FFFF0000LL, // _amask4_2_2   offset 200  (bpp 2, sub)
+
+};
+
+#define MASK8_0        "(%%rbp)"
+#define MASK16_0       "8(%%rbp)"
+#define MASK16_1       "16(%%rbp)"
+#define MASK24_0       "24(%%rbp)"
+#define MASK24_1       "32(%%rbp)"
+#define MASK24_2       "40(%%rbp)"
+#define MASK32_0       "48(%%rbp)"
+#define MASK32_1       "56(%%rbp)"
+#define MASK32_2       "64(%%rbp)"
+#define MASK32_3       "72(%%rbp)"
+#define MASK48_0       "80(%%rbp)"
+#define MASK48_1       "88(%%rbp)"
+#define MASK48_2       "96(%%rbp)"
+#define MASK48_3       "104(%%rbp)"
+#define MASK48_4       "112(%%rbp)"
+#define MASK48_5       "120(%%rbp)"
+#define AMASK5_3_0     "128(%%rbp)"
+#define AMASK7_1_0     "136(%%rbp)"
+#define LB_CARRY_MASK  "144(%%rbp)"
+#define HB_CLEAR_MASK  "152(%%rbp)"
+#define AMASK0_8_0     "160(%%rbp)"
+#define AMASK6_2_0     "168(%%rbp)"
+#define AMASK4_4_0     "176(%%rbp)"
+#define AMASK0_2_6     "184(%%rbp)"
+#define AMASK2_3_3     "192(%%rbp)"
+#define AMASK4_2_2     "200(%%rbp)"
+
+#else // !PNG_x86_64_USE_GOTPCREL
+
+static PNG_CONST ull _mask8_0  __attribute__((used, aligned(8))) = 0x0102040810204080LL;
+
+static PNG_CONST ull _mask16_1 __attribute__((used, aligned(8))) = 0x0101020204040808LL;
+static PNG_CONST ull _mask16_0 __attribute__((used, aligned(8))) = 0x1010202040408080LL;
+
+static PNG_CONST ull _mask24_2 __attribute__((used, aligned(8))) = 0x0101010202020404LL;
+static PNG_CONST ull _mask24_1 __attribute__((used, aligned(8))) = 0x0408080810101020LL;
+static PNG_CONST ull _mask24_0 __attribute__((used, aligned(8))) = 0x2020404040808080LL;
+
+static PNG_CONST ull _mask32_3 __attribute__((used, aligned(8))) = 0x0101010102020202LL;
+static PNG_CONST ull _mask32_2 __attribute__((used, aligned(8))) = 0x0404040408080808LL;
+static PNG_CONST ull _mask32_1 __attribute__((used, aligned(8))) = 0x1010101020202020LL;
+static PNG_CONST ull _mask32_0 __attribute__((used, aligned(8))) = 0x4040404080808080LL;
+
+static PNG_CONST ull _mask48_5 __attribute__((used, aligned(8))) = 0x0101010101010202LL;
+static PNG_CONST ull _mask48_4 __attribute__((used, aligned(8))) = 0x0202020204040404LL;
+static PNG_CONST ull _mask48_3 __attribute__((used, aligned(8))) = 0x0404080808080808LL;
+static PNG_CONST ull _mask48_2 __attribute__((used, aligned(8))) = 0x1010101010102020LL;
+static PNG_CONST ull _mask48_1 __attribute__((used, aligned(8))) = 0x2020202040404040LL;
+static PNG_CONST ull _mask48_0 __attribute__((used, aligned(8))) = 0x4040808080808080LL;
+
+// png_do_read_interlace() constants:
+static PNG_CONST ull _amask5_3_0  __attribute__((aligned(8))) = 0x0000000000FFFFFFLL;  // was _const4
+static PNG_CONST ull _amask7_1_0  __attribute__((aligned(8))) = 0x00000000000000FFLL;  // was _const6
+
+// png_read_filter_row_mmx_avg() constants:
+static PNG_CONST ull _LBCarryMask __attribute__((used, aligned(8))) = 0x0101010101010101LL;
+static PNG_CONST ull _HBClearMask __attribute__((used, aligned(8))) = 0x7f7f7f7f7f7f7f7fLL;
+static PNG_CONST ull _amask0_8_0  __attribute__((used, aligned(8))) = 0xFFFFFFFFFFFFFFFFLL;
+static PNG_CONST ull _amask6_2_0  __attribute__((used, aligned(8))) = 0x000000000000FFFFLL;
+
+// png_read_filter_row_mmx_paeth() constants:
+static PNG_CONST ull _amask4_4_0  __attribute__((used, aligned(8))) = 0x00000000FFFFFFFFLL;
+static PNG_CONST ull _amask0_2_6  __attribute__((used, aligned(8))) = 0xFFFF000000000000LL;
+
+// png_read_filter_row_mmx_sub() constants:
+static PNG_CONST ull _amask2_3_3  __attribute__((used, aligned(8))) = 0x0000FFFFFF000000LL;
+static PNG_CONST ull _amask4_2_2  __attribute__((used, aligned(8))) = 0x00000000FFFF0000LL;
+
+#define MASK8_0        "_mask8_0"
+#define MASK16_0       "_mask16_0"
+#define MASK16_1       "_mask16_1"
+#define MASK24_0       "_mask24_0"
+#define MASK24_1       "_mask24_1"
+#define MASK24_2       "_mask24_2"
+#define MASK32_0       "_mask32_0"
+#define MASK32_1       "_mask32_1"
+#define MASK32_2       "_mask32_2"
+#define MASK32_3       "_mask32_3"
+#define MASK48_0       "_mask48_0"
+#define MASK48_1       "_mask48_1"
+#define MASK48_2       "_mask48_2"
+#define MASK48_3       "_mask48_3"
+#define MASK48_4       "_mask48_4"
+#define MASK48_5       "_mask48_5"
+#define AMASK5_3_0     "_amask5_3_0"
+#define AMASK7_1_0     "_amask7_1_0"
+#define LB_CARRY_MASK  "_LBCarryMask"
+#define HB_CLEAR_MASK  "_HBClearMask"
+#define AMASK0_8_0     "_amask0_8_0"
+#define AMASK6_2_0     "_amask6_2_0"
+#define AMASK4_4_0     "_amask4_4_0"
+#define AMASK0_2_6     "_amask0_2_6"
+#define AMASK2_3_3     "_amask2_3_3"
+#define AMASK4_2_2     "_amask4_2_2"
+
+#endif // ?PNG_x86_64_USE_GOTPCREL
+
+
+#if defined(PNG_HAVE_MMX_READ_FILTER_ROW) || defined(PNG_HAVE_MMX_COMBINE_ROW)
+
+// this block is specific to png_read_filter_row_mmx_paeth() except for
+// LOAD_GOT_rbp and RESTORE_rbp, which are also used in png_combine_row()
+#if defined(PNG_x86_64_USE_GOTPCREL)
+#  define pa_TEMP                "%%r11d"
+#  define pb_TEMP                "%%r12d"
+#  define pc_TEMP                "%%r13d"
+#  if defined(PNG_CLOBBER_x86_64_REGS_SUPPORTED)  // works as of gcc 3.4.3 ...
+#    define SAVE_r11_r12_r13
+#    define RESTORE_r11_r12_r13
+#    define _CLOBBER_r11_r12_r13 ,"%r11", "%r12", "%r13"
+#    define CLOBBER_r11_r12_r13  "%r11", "%r12", "%r13"
+#  else // !PNG_CLOBBER_x86_64_REGS_SUPPORTED
+#    define SAVE_r11_r12_r13     "pushq %%r11  \n\t" \
+                                 "pushq %%r12  \n\t" \
+                                 "pushq %%r13  \n\t"  // "normally 0-extended"
+#    define RESTORE_r11_r12_r13  "popq  %%r13  \n\t" \
+                                 "popq  %%r12  \n\t" \
+                                 "popq  %%r11  \n\t"
+#    define _CLOBBER_r11_r12_r13
+#    define CLOBBER_r11_r12_r13
+#  endif
+#  define LOAD_GOT_rbp           "pushq %%rbp                        \n\t" \
+                                 "movq  _c64@GOTPCREL(%%rip), %%rbp  \n\t"
+#  define RESTORE_rbp            "popq  %%rbp                        \n\t"
+#else // 32-bit and/or non-PIC
+#  if defined(PNG_THREAD_UNSAFE_OK)
+     // These variables are used in png_read_filter_row_mmx_paeth() and would be
+     //   local variables if not for gcc-inline-assembly addressing limitations
+     //   (some apparently related to ELF format, others to CPU type).
+     //
+     // WARNING: Their presence defeats the thread-safety of libpng.
+     static int                     _patemp  __attribute__((used));
+     static int                     _pbtemp  __attribute__((used));
+     static int                     _pctemp  __attribute__((used));
+#    define pa_TEMP                "_patemp"
+#    define pb_TEMP                "_pbtemp"  // temp variables for
+#    define pc_TEMP                "_pctemp"  //  Paeth routine
+#    define SAVE_r11_r12_r13
+#    define RESTORE_r11_r12_r13
+#    define _CLOBBER_r11_r12_r13   // not using regs => not clobbering
+#    define CLOBBER_r11_r12_r13
+#  endif // PNG_THREAD_UNSAFE_OK
+#  define LOAD_GOT_rbp
+#  define RESTORE_rbp
+#endif
+
+#if defined(__x86_64__)
+#  define SAVE_ebp
+#  define RESTORE_ebp
+#  define _CLOBBER_ebp         ,"%ebp"
+#  define CLOBBER_ebp          "%ebp"
+#  define SAVE_FullLength      "movl %%eax, %%r15d  \n\t"
+#  define RESTORE_FullLength   "movl %%r15d, "     // may go into eax or ecx
+#  if defined(PNG_CLOBBER_x86_64_REGS_SUPPORTED)   // works as of gcc 3.4.3 ...
+#    define SAVE_r15
+#    define RESTORE_r15
+#    define _CLOBBER_r15       ,"%r15"
+#  else
+#    define SAVE_r15           "pushq %%r15  \n\t"
+#    define RESTORE_r15        "popq  %%r15  \n\t"
+#    define _CLOBBER_r15
+#  endif
+#  define PBP                  "%%rbp"             // regs used for 64-bit
+#  define PAX                  "%%rax"             //  pointers or in
+#  define PBX                  "%%rbx"             //  combination with
+#  define PCX                  "%%rcx"             //  64-bit pointer-regs
+#  define PDX                  "%%rdx"             //  (base/index pairs,
+#  define PSI                  "%%rsi"             //  add/sub/mov pairs)
+#  define CLEAR_BOTTOM_3_BITS  "and  $0xfffffffffffffff8, "
+#else
+#  define SAVE_ebp             "pushl %%ebp \n\t"  // clobber list doesn't work
+#  define RESTORE_ebp          "popl  %%ebp \n\t"  //  for %ebp on 32-bit; not
+#  define _CLOBBER_ebp                             //  clear why not
+#  define CLOBBER_ebp
+#  define SAVE_FullLength      "pushl %%eax \n\t"
+#  define RESTORE_FullLength   "popl "             // eax (avg) or ecx (paeth)
+#  define SAVE_r15
+#  define RESTORE_r15
+#  define _CLOBBER_r15
+#  define PBP                  "%%ebp"             // regs used for or in
+#  define PAX                  "%%eax"             //  combination with
+#  define PBX                  "%%ebx"             //  "normal," 32-bit
+#  define PCX                  "%%ecx"             //  pointers
+#  define PDX                  "%%edx"
+#  define PSI                  "%%esi"
+#  define CLEAR_BOTTOM_3_BITS  "and  $0xfffffff8, "
+#endif
+
+// CLOB_COMMA_ebx_ebp:  need comma ONLY if both CLOBBER_ebp and CLOBBER_GOT_ebx
+//                      have values, i.e., only if __x86_64__ AND !__PIC__
+#if defined(__x86_64__) && !defined(__PIC__)
+#  define CLOB_COMMA_ebx_ebp    , // clobbering both ebp and ebx => need comma
+#else
+#  define CLOB_COMMA_ebx_ebp
+#endif
+
+// CLOB_COMMA_ebX_r1X:  need comma UNLESS both CLOBBER_ebp and CLOBBER_GOT_ebx
+//                   are empty OR CLOBBER_r11_r12_r13 is empty--i.e., NO comma
+//                   if (!__x86_64__ AND __PIC__) OR !(PNG_x86_64_USE_GOTPCREL
+//                   AND PNG_CLOBBER_x86_64_REGS_SUPPORTED)   (double sigh...)
+#if (!defined(__x86_64__) && defined(__PIC__)) || \
+    !defined(PNG_x86_64_USE_GOTPCREL) || \
+    !defined(PNG_CLOBBER_x86_64_REGS_SUPPORTED)
+#  define CLOB_COMMA_ebX_r1X
+#else
+#  define CLOB_COMMA_ebX_r1X    , // clobbering (ebp OR ebx) AND r11_r12_r13
+#endif
+
+// CLOB_COLON_ebx_ebp:  need colon unless CLOBBER_ebp and CLOBBER_GOT_ebx are
+//                      BOTH empty--i.e., NO colon if (!__x86_64__ AND __PIC__)
+// CLOB_COLON_ebx_ebp_r1X:  if, in addition, CLOBBER_r11_r12_r13 is empty, then
+//                          no colon for Paeth blocks, either--i.e., NO colon
+//                          if !(PNG_x86_64_USE_GOTPCREL AND
+//                               PNG_CLOBBER_x86_64_REGS_SUPPORTED)
+#if (!defined(__x86_64__) && defined(__PIC__))
+#  define CLOB_COLON_ebx_ebp
+#  if !(defined(PNG_x86_64_USE_GOTPCREL) && \
+        defined(PNG_CLOBBER_x86_64_REGS_SUPPORTED))
+#    define CLOB_COLON_ebx_ebp_r1X
+#  else
+#    define CLOB_COLON_ebx_ebp_r1X  : // clobbering ebp OR ebx OR r11_r12_r13
+#  endif
+#else
+#  define CLOB_COLON_ebx_ebp        : // clobbering ebp OR ebx
+#  define CLOB_COLON_ebx_ebp_r1X    : // clobbering ebp OR ebx OR r11_r12_r13
+#endif
+
+#endif // PNG_HAVE_MMX_READ_FILTER_ROW
+
+#if defined(__PIC__)  // macros to save, restore index to Global Offset Table
+#  if defined(__x86_64__)
+#    define SAVE_GOT_ebx     "pushq %%rbx \n\t"
+#    define RESTORE_GOT_ebx  "popq  %%rbx \n\t"
+#  else
+#    define SAVE_GOT_ebx     "pushl %%ebx \n\t"
+#    define RESTORE_GOT_ebx  "popl  %%ebx \n\t"
+#  endif
+#  define _CLOBBER_GOT_ebx   // explicitly saved, restored => not clobbered
+#  define CLOBBER_GOT_ebx
+#else
+#  define SAVE_GOT_ebx
+#  define RESTORE_GOT_ebx
+#  define _CLOBBER_GOT_ebx   ,"%ebx"
+#  define CLOBBER_GOT_ebx    "%ebx"
+#endif
+
+#if defined(PNG_HAVE_MMX_COMBINE_ROW) || defined(PNG_HAVE_MMX_READ_INTERLACE)
+#  define BPP2  2
+#  define BPP3  3  // bytes per pixel (a.k.a. pixel_bytes)
+#  define BPP4  4  // (defined only to help avoid cut-and-paste errors)
+#  define BPP6  6
+#  define BPP8  8
+#endif
+
+
+
+static int _mmx_supported = 2; // 0: no MMX; 1: MMX supported; 2: not tested
+
+/*===========================================================================*/
+/*                                                                           */
+/*                      P N G _ M M X _ S U P P O R T                        */
+/*                                                                           */
+/*===========================================================================*/
+
+// GRR NOTES:  (1) the following code assumes 386 or better (pushfl/popfl)
+//             (2) all instructions compile with gcc 2.7.2.3 and later
+//           x (3) the function is moved down here to prevent gcc from
+//           x      inlining it in multiple places and then barfing be-
+//           x      cause the ".NOT_SUPPORTED" label is multiply defined
+//                  [need to retest with gcc 2.7.2.3]
+
+// GRR 20070524:  This declaration apparently is compatible with but supersedes
+//   the one in png.h; in any case, the generated object file is slightly
+//   smaller.  It is unnecessary with gcc 4.1.2, but gcc 2.x apparently
+//   replicated the ".NOT_SUPPORTED" label in each location the function was
+//   inlined, leading to compilation errors due to the "multiply defined"
+//   label.  Old workaround was to leave the function at the end of this
+//   file; new one (still testing) is to use a gcc-specific function attribute
+//   to prevent local inlining.
+int PNGAPI
+png_mmx_support(void) __attribute__((noinline));
+
+int PNGAPI
+png_mmx_support(void)
+{
+#if defined(PNG_MMX_CODE_SUPPORTED)  // superfluous, but what the heck
+    int result;
+    __asm__ __volatile__ (
+#if defined(__x86_64__)
+        "pushq %%rbx          \n\t"  // rbx gets clobbered by CPUID instruction
+        "pushq %%rcx          \n\t"  // so does rcx...
+        "pushq %%rdx          \n\t"  // ...and rdx (but rcx & rdx safe on Linux)
+        "pushfq               \n\t"  // save Eflag to stack
+        "popq %%rax           \n\t"  // get Eflag from stack into rax
+        "movq %%rax, %%rcx    \n\t"  // make another copy of Eflag in rcx
+        "xorl $0x200000, %%eax \n\t" // toggle ID bit in Eflag (i.e., bit 21)
+        "pushq %%rax          \n\t"  // save modified Eflag back to stack
+        "popfq                \n\t"  // restore modified value to Eflag reg
+        "pushfq               \n\t"  // save Eflag to stack
+        "popq %%rax           \n\t"  // get Eflag from stack
+        "pushq %%rcx          \n\t"  // save original Eflag to stack
+        "popfq                \n\t"  // restore original Eflag
+#else
+        "pushl %%ebx          \n\t"  // ebx gets clobbered by CPUID instruction
+        "pushl %%ecx          \n\t"  // so does ecx...
+        "pushl %%edx          \n\t"  // ...and edx (but ecx & edx safe on Linux)
+        "pushfl               \n\t"  // save Eflag to stack
+        "popl %%eax           \n\t"  // get Eflag from stack into eax
+        "movl %%eax, %%ecx    \n\t"  // make another copy of Eflag in ecx
+        "xorl $0x200000, %%eax \n\t" // toggle ID bit in Eflag (i.e., bit 21)
+        "pushl %%eax          \n\t"  // save modified Eflag back to stack
+        "popfl                \n\t"  // restore modified value to Eflag reg
+        "pushfl               \n\t"  // save Eflag to stack
+        "popl %%eax           \n\t"  // get Eflag from stack
+        "pushl %%ecx          \n\t"  // save original Eflag to stack
+        "popfl                \n\t"  // restore original Eflag
+#endif
+        "xorl %%ecx, %%eax    \n\t"  // compare new Eflag with original Eflag
+        "jz 0f                \n\t"  // if same, CPUID instr. is not supported
+
+        "xorl %%eax, %%eax    \n\t"  // set eax to zero
+//      ".byte  0x0f, 0xa2    \n\t"  // CPUID instruction (two-byte opcode)
+        "cpuid                \n\t"  // get the CPU identification info
+        "cmpl $1, %%eax       \n\t"  // make sure eax return non-zero value
+        "jl 0f                \n\t"  // if eax is zero, MMX is not supported
+
+        "xorl %%eax, %%eax    \n\t"  // set eax to zero and...
+        "incl %%eax           \n\t"  // ...increment eax to 1.  This pair is
+                                     // faster than the instruction "mov eax, 1"
+        "cpuid                \n\t"  // get the CPU identification info again
+        "andl $0x800000, %%edx \n\t" // mask out all bits but MMX bit (23)
+        "cmpl $0, %%edx       \n\t"  // 0 = MMX not supported
+        "jz 0f                \n\t"  // non-zero = yes, MMX IS supported
+
+        "movl $1, %%eax       \n\t"  // set return value to 1
+        "jmp  1f              \n\t"  // DONE:  have MMX support
+
+    "0:                       \n\t"  // .NOT_SUPPORTED: target label for jump instructions
+        "movl $0, %%eax       \n\t"  // set return value to 0
+    "1:                       \n\t"  // .RETURN: target label for jump instructions
+#if defined(__x86_64__)
+        "popq %%rdx           \n\t"  // restore rdx
+        "popq %%rcx           \n\t"  // restore rcx
+        "popq %%rbx           \n\t"  // restore rbx
+#else
+        "popl %%edx           \n\t"  // restore edx
+        "popl %%ecx           \n\t"  // restore ecx
+        "popl %%ebx           \n\t"  // restore ebx
+#endif
+
+//      "ret                  \n\t"  // DONE:  no MMX support
+                                     // (fall through to standard C "ret")
+
+        : "=a" (result)              // output list
+
+        :                            // any variables used on input (none)
+
+                                     // no clobber list
+//      , "%ebx", "%ecx", "%edx"     // GRR:  we handle these manually
+//      , "memory"   // if write to a variable gcc thought was in a reg
+//      , "cc"       // "condition codes" (flag bits)
+    );
+    _mmx_supported = result;
+#else
+    _mmx_supported = 0;
+#endif /* PNG_MMX_CODE_SUPPORTED */
+
+    return _mmx_supported;
+}
+
+
+/*===========================================================================*/
+/*                                                                           */
+/*                       P N G _ C O M B I N E _ R O W                       */
+/*                                                                           */
+/*===========================================================================*/
+
+#if defined(PNG_HAVE_MMX_COMBINE_ROW)
+
+/* Combines the row recently read in with the previous row.
+   This routine takes care of alpha and transparency if requested.
+   This routine also handles the two methods of progressive display
+   of interlaced images, depending on the mask value.
+   The mask value describes which pixels are to be combined with
+   the row.  The pattern always repeats every 8 pixels, so just 8
+   bits are needed.  A one indicates the pixel is to be combined; a
+   zero indicates the pixel is to be skipped.  This is in addition
+   to any alpha or transparency value associated with the pixel.
+   If you want all pixels to be combined, pass 0xff (255) in mask. */
+
+/* Use this routine for the x86 platform - it uses a faster MMX routine
+   if the machine supports MMX. */
+
+void /* PRIVATE */
+png_combine_row(png_structp png_ptr, png_bytep row, int mask)
+{
+   int dummy_value_a;    // fix 'forbidden register spilled' error
+   int dummy_value_c;
+   int dummy_value_d;
+   png_bytep dummy_value_S;
+   png_bytep dummy_value_D;
+
+   png_debug(1, "in png_combine_row (pnggccrd.c)\n");
+
+   if (_mmx_supported == 2) {
+#if !defined(PNG_1_0_X)
+       /* this should have happened in png_init_mmx_flags() already */
+       png_warning(png_ptr, "asm_flags may not have been initialized");
+#endif
+       png_mmx_support();
+   }
+
+   if (mask == 0xff)
+   {
+      png_debug(2,"mask == 0xff:  doing single png_memcpy()\n");
+      png_memcpy(row, png_ptr->row_buf + 1,
+       (png_size_t)PNG_ROWBYTES(png_ptr->row_info.pixel_depth,png_ptr->width));
+   }
+   else   /* (png_combine_row() is never called with mask == 0) */
+   {
+      switch (png_ptr->row_info.pixel_depth)
+      {
+         case 24:       /* png_ptr->row_info.pixel_depth */
+         {
+            png_bytep srcptr;
+            png_bytep dstptr;
+
+#if !defined(PNG_1_0_X)
+            if (png_ptr->asm_flags & PNG_ASM_FLAG_MMX_READ_COMBINE_ROW)
+#else
+            if (_mmx_supported)
+#endif
+            {
+               png_uint_32 len;
+               int diff;
+
+               srcptr = png_ptr->row_buf + 1;
+               dstptr = row;
+               len  = png_ptr->width & ~7;          // reduce to multiple of 8
+               diff = (int) (png_ptr->width & 7);   // amount lost
+
+               __asm__ __volatile__ (
+                  "not       %%edx            \n\t" // mask => unmask
+                  "movd      %%edx, %%mm7     \n\t" // load bit pattern
+                  "not       %%edx            \n\t" // unmask => mask for later
+                  "psubb     %%mm6, %%mm6     \n\t" // zero mm6
+                  "punpcklbw %%mm7, %%mm7     \n\t"
+                  "punpcklwd %%mm7, %%mm7     \n\t"
+                  "punpckldq %%mm7, %%mm7     \n\t" // fill reg with 8 masks
+
+                  LOAD_GOT_rbp
+                  "movq   " MASK24_0 ", %%mm0 \n\t" // _mask24_0 -> mm0
+                  "movq   " MASK24_1 ", %%mm1 \n\t" // _mask24_1 -> mm1
+                  "movq   " MASK24_2 ", %%mm2 \n\t" // _mask24_2 -> mm2
+                  RESTORE_rbp
+
+                  "pand      %%mm7, %%mm0     \n\t"
+                  "pand      %%mm7, %%mm1     \n\t"
+                  "pand      %%mm7, %%mm2     \n\t"
+
+                  "pcmpeqb   %%mm6, %%mm0     \n\t"
+                  "pcmpeqb   %%mm6, %%mm1     \n\t"
+                  "pcmpeqb   %%mm6, %%mm2     \n\t"
+
+// preload        "movl      len, %%ecx       \n\t" // load length of line
+// preload        "movl      srcptr, %3       \n\t" // load source
+// preload        "movl      dstptr, %4       \n\t" // load dest
+
+                  "cmpl      $0, %%ecx        \n\t"
+                  "jz        mainloop24end    \n\t"
+
+                "mainloop24:                  \n\t"
+                  "movq      (%3), %%mm4      \n\t"
+                  "pand      %%mm0, %%mm4     \n\t"
+                  "movq      %%mm0, %%mm6     \n\t"
+                  "movq      (%4), %%mm7      \n\t"
+                  "pandn     %%mm7, %%mm6     \n\t"
+                  "por       %%mm6, %%mm4     \n\t"
+                  "movq      %%mm4, (%4)      \n\t"
+
+                  "movq      8(%3), %%mm5     \n\t"
+                  "pand      %%mm1, %%mm5     \n\t"
+                  "movq      %%mm1, %%mm7     \n\t"
+                  "movq      8(%4), %%mm6     \n\t"
+                  "pandn     %%mm6, %%mm7     \n\t"
+                  "por       %%mm7, %%mm5     \n\t"
+                  "movq      %%mm5, 8(%4)     \n\t"
+
+                  "movq      16(%3), %%mm6    \n\t"
+                  "pand      %%mm2, %%mm6     \n\t"
+                  "movq      %%mm2, %%mm4     \n\t"
+                  "movq      16(%4), %%mm7    \n\t"
+                  "pandn     %%mm7, %%mm4     \n\t"
+                  "por       %%mm4, %%mm6     \n\t"
+                  "movq      %%mm6, 16(%4)    \n\t"
+
+                  "add       $24, %3          \n\t" // inc by 24 bytes processed
+                  "add       $24, %4          \n\t"
+                  "subl      $8, %%ecx        \n\t" // dec by 8 pixels processed
+
+                  "ja        mainloop24       \n\t"
+
+                "mainloop24end:               \n\t"
+// preload        "movl      diff, %%ecx      \n\t" // (diff is in eax)
+                  "movl      %%eax, %%ecx     \n\t"
+                  "cmpl      $0, %%ecx        \n\t"
+                  "jz        end24            \n\t"
+// preload        "movl      mask, %%edx      \n\t"
+                  "sall      $24, %%edx       \n\t" // make low byte, high byte
+
+                "secondloop24:                \n\t"
+                  "sall      %%edx            \n\t" // move high bit to CF
+                  "jnc       skip24           \n\t" // if CF = 0
+                  "movw      (%3), %%ax       \n\t"
+                  "movw      %%ax, (%4)       \n\t"
+                  "xorl      %%eax, %%eax     \n\t"
+                  "movb      2(%3), %%al      \n\t"
+                  "movb      %%al, 2(%4)      \n\t"
+
+                "skip24:                      \n\t"
+                  "add       $3, %3           \n\t"
+                  "add       $3, %4           \n\t"
+                  "decl      %%ecx            \n\t"
+                  "jnz       secondloop24     \n\t"
+
+                "end24:                       \n\t"
+                  "EMMS                       \n\t" // DONE
+
+                  : "=a" (dummy_value_a),           // output regs (dummy)
+                    "=d" (dummy_value_d),
+                    "=c" (dummy_value_c),
+                    "=S" (dummy_value_S),
+                    "=D" (dummy_value_D)
+
+                  : "0" (diff),        // eax       // input regs
+                    "1" (mask),        // edx
+                    "2" (len),         // ecx
+// was (unmask)     "b"    RESERVED    // ebx       // Global Offset Table idx
+                    "3" (srcptr),      // esi/rsi
+                    "4" (dstptr)       // edi/rdi
+
+#if defined(PNG_CLOBBER_MMX_REGS_SUPPORTED)
+                  : "%mm0", "%mm1", "%mm2"          // clobber list
+                  , "%mm4", "%mm5", "%mm6", "%mm7"
+#endif
+               );
+            }
+            else /* not _mmx_supported - use modified C routine */
+            {
+               register png_uint_32 i;
+               png_uint_32 initial_val = BPP3 * png_pass_start[png_ptr->pass];
+                 /* png.c:  png_pass_start[] = {0, 4, 0, 2, 0, 1, 0}; */
+               register int stride = BPP3 * png_pass_inc[png_ptr->pass];
+                 /* png.c:  png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1}; */
+               register int rep_bytes = BPP3 * png_pass_width[png_ptr->pass];
+                 /* png.c:  png_pass_width[] = {8, 4, 4, 2, 2, 1, 1}; */
+               png_uint_32 len = png_ptr->width &~7;  /* reduce to mult. of 8 */
+               int diff = (int) (png_ptr->width & 7); /* amount lost */
+               register png_uint_32 final_val = BPP3 * len;   /* GRR bugfix */
+
+               srcptr = png_ptr->row_buf + 1 + initial_val;
+               dstptr = row + initial_val;
+
+               for (i = initial_val; i < final_val; i += stride)
+               {
+                  png_memcpy(dstptr, srcptr, rep_bytes);
+                  srcptr += stride;
+                  dstptr += stride;
+               }
+               if (diff)  /* number of leftover pixels:  3 for pngtest */
+               {
+                  final_val += diff*BPP3;
+                  for (; i < final_val; i += stride)
+                  {
+                     if (rep_bytes > (int)(final_val-i))
+                        rep_bytes = (int)(final_val-i);
+                     png_memcpy(dstptr, srcptr, rep_bytes);
+                     srcptr += stride;
+                     dstptr += stride;
+                  }
+               }
+            } /* end of else (_mmx_supported) */
+
+            break;
+         }       /* end 24 bpp */
+
+         // formerly claimed to be most common case (combining 32-bit RGBA),
+         // but almost certainly less common than 24-bit RGB case
+         case 32:       /* png_ptr->row_info.pixel_depth */
+         {
+            png_bytep srcptr;
+            png_bytep dstptr;
+
+#if !defined(PNG_1_0_X)
+            if (png_ptr->asm_flags & PNG_ASM_FLAG_MMX_READ_COMBINE_ROW)
+#else
+            if (_mmx_supported)
+#endif
+            {
+               png_uint_32 len;
+               int diff;
+
+               srcptr = png_ptr->row_buf + 1;
+               dstptr = row;
+               len  = png_ptr->width & ~7;          // reduce to multiple of 8
+               diff = (int) (png_ptr->width & 7);   // amount lost
+
+               __asm__ __volatile__ (
+                  "not       %%edx            \n\t" // mask => unmask
+                  "movd      %%edx, %%mm7     \n\t" // load bit pattern
+                  "not       %%edx            \n\t" // unmask => mask for later
+                  "psubb     %%mm6, %%mm6     \n\t" // zero mm6
+                  "punpcklbw %%mm7, %%mm7     \n\t"
+                  "punpcklwd %%mm7, %%mm7     \n\t"
+                  "punpckldq %%mm7, %%mm7     \n\t" // fill reg with 8 masks
+
+                  LOAD_GOT_rbp
+                  "movq   " MASK32_0 ", %%mm0 \n\t" // _mask32_0
+                  "movq   " MASK32_1 ", %%mm1 \n\t" // _mask32_1
+                  "movq   " MASK32_2 ", %%mm2 \n\t" // _mask32_2
+                  "movq   " MASK32_3 ", %%mm3 \n\t" // _mask32_3
+                  RESTORE_rbp
+
+                  "pand      %%mm7, %%mm0     \n\t"
+                  "pand      %%mm7, %%mm1     \n\t"
+                  "pand      %%mm7, %%mm2     \n\t"
+                  "pand      %%mm7, %%mm3     \n\t"
+
+                  "pcmpeqb   %%mm6, %%mm0     \n\t"
+                  "pcmpeqb   %%mm6, %%mm1     \n\t"
+                  "pcmpeqb   %%mm6, %%mm2     \n\t"
+                  "pcmpeqb   %%mm6, %%mm3     \n\t"
+
+// preload        "movl      len, %%ecx       \n\t" // load length of line
+// preload        "movl      srcptr, %3       \n\t" // load source
+// preload        "movl      dstptr, %4       \n\t" // load dest
+
+                  "cmpl      $0, %%ecx        \n\t" // lcr
+                  "jz        mainloop32end    \n\t"
+
+                "mainloop32:                  \n\t"
+                  "movq      (%3), %%mm4      \n\t"
+                  "pand      %%mm0, %%mm4     \n\t"
+                  "movq      %%mm0, %%mm6     \n\t"
+                  "movq      (%4), %%mm7      \n\t"
+                  "pandn     %%mm7, %%mm6     \n\t"
+                  "por       %%mm6, %%mm4     \n\t"
+                  "movq      %%mm4, (%4)      \n\t"
+
+                  "movq      8(%3), %%mm5     \n\t"
+                  "pand      %%mm1, %%mm5     \n\t"
+                  "movq      %%mm1, %%mm7     \n\t"
+                  "movq      8(%4), %%mm6     \n\t"
+                  "pandn     %%mm6, %%mm7     \n\t"
+                  "por       %%mm7, %%mm5     \n\t"
+                  "movq      %%mm5, 8(%4)     \n\t"
+
+                  "movq      16(%3), %%mm6    \n\t"
+                  "pand      %%mm2, %%mm6     \n\t"
+                  "movq      %%mm2, %%mm4     \n\t"
+                  "movq      16(%4), %%mm7    \n\t"
+                  "pandn     %%mm7, %%mm4     \n\t"
+                  "por       %%mm4, %%mm6     \n\t"
+                  "movq      %%mm6, 16(%4)    \n\t"
+
+                  "movq      24(%3), %%mm7    \n\t"
+                  "pand      %%mm3, %%mm7     \n\t"
+                  "movq      %%mm3, %%mm5     \n\t"
+                  "movq      24(%4), %%mm4    \n\t"
+                  "pandn     %%mm4, %%mm5     \n\t"
+                  "por       %%mm5, %%mm7     \n\t"
+                  "movq      %%mm7, 24(%4)    \n\t"
+
+                  "add       $32, %3          \n\t" // inc by 32 bytes processed
+                  "add       $32, %4          \n\t"
+                  "subl      $8, %%ecx        \n\t" // dec by 8 pixels processed
+                  "ja        mainloop32       \n\t"
+
+                "mainloop32end:               \n\t"
+// preload        "movl      diff, %%ecx      \n\t" // (diff is in eax)
+                  "movl      %%eax, %%ecx     \n\t"
+                  "cmpl      $0, %%ecx        \n\t"
+                  "jz        end32            \n\t"
+// preload        "movl      mask, %%edx      \n\t"
+                  "sall      $24, %%edx       \n\t" // low byte => high byte
+
+                "secondloop32:                \n\t"
+                  "sall      %%edx            \n\t" // move high bit to CF
+                  "jnc       skip32           \n\t" // if CF = 0
+                  "movl      (%3), %%eax      \n\t"
+                  "movl      %%eax, (%4)      \n\t"
+
+                "skip32:                      \n\t"
+                  "add       $4, %3           \n\t"
+                  "add       $4, %4           \n\t"
+                  "decl      %%ecx            \n\t"
+                  "jnz       secondloop32     \n\t"
+
+                "end32:                       \n\t"
+                  "EMMS                       \n\t" // DONE
+
+                  : "=a" (dummy_value_a),           // output regs (dummy)
+                    "=d" (dummy_value_d),
+                    "=c" (dummy_value_c),
+                    "=S" (dummy_value_S),
+                    "=D" (dummy_value_D)
+
+                  : "0" (diff),        // eax       // input regs
+                    "1" (mask),        // edx
+                    "2" (len),         // ecx
+// was (unmask)     "b"    RESERVED    // ebx       // Global Offset Table idx
+                    "3" (srcptr),      // esi/rsi
+                    "4" (dstptr)       // edi/rdi
+
+#if defined(PNG_CLOBBER_MMX_REGS_SUPPORTED)
+                  : "%mm0", "%mm1", "%mm2", "%mm3"  // clobber list
+                  , "%mm4", "%mm5", "%mm6", "%mm7"
+#endif
+               );
+            }
+            else /* not _mmx_supported - use modified C routine */
+            {
+               register png_uint_32 i;
+               png_uint_32 initial_val = BPP4 * png_pass_start[png_ptr->pass];
+                 /* png.c:  png_pass_start[] = {0, 4, 0, 2, 0, 1, 0}; */
+               register int stride = BPP4 * png_pass_inc[png_ptr->pass];
+                 /* png.c:  png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1}; */
+               register int rep_bytes = BPP4 * png_pass_width[png_ptr->pass];
+                 /* png.c:  png_pass_width[] = {8, 4, 4, 2, 2, 1, 1}; */
+               png_uint_32 len = png_ptr->width &~7;  /* reduce to mult. of 8 */
+               int diff = (int) (png_ptr->width & 7); /* amount lost */
+               register png_uint_32 final_val = BPP4 * len;   /* GRR bugfix */
+
+               srcptr = png_ptr->row_buf + 1 + initial_val;
+               dstptr = row + initial_val;
+
+               for (i = initial_val; i < final_val; i += stride)
+               {
+                  png_memcpy(dstptr, srcptr, rep_bytes);
+                  srcptr += stride;
+                  dstptr += stride;
+               }
+               if (diff)  /* number of leftover pixels:  3 for pngtest */
+               {
+                  final_val += diff*BPP4;
+                  for (; i < final_val; i += stride)
+                  {
+                     if (rep_bytes > (int)(final_val-i))
+                        rep_bytes = (int)(final_val-i);
+                     png_memcpy(dstptr, srcptr, rep_bytes);
+                     srcptr += stride;
+                     dstptr += stride;
+                  }
+               }
+            } /* end of else (_mmx_supported) */
+
+            break;
+         }       /* end 32 bpp */
+
+         case 8:        /* png_ptr->row_info.pixel_depth */
+         {
+            png_bytep srcptr;
+            png_bytep dstptr;
+
+#if !defined(PNG_1_0_X)
+            if (png_ptr->asm_flags & PNG_ASM_FLAG_MMX_READ_COMBINE_ROW)
+#else
+            if (_mmx_supported)
+#endif
+            {
+               png_uint_32 len;
+               int diff;
+
+               srcptr = png_ptr->row_buf + 1;
+               dstptr = row;
+               len  = png_ptr->width & ~7;          // reduce to multiple of 8
+               diff = (int) (png_ptr->width & 7);   // amount lost
+
+               __asm__ __volatile__ (
+                  "not       %%edx            \n\t" // mask => unmask
+                  "movd      %%edx, %%mm7     \n\t" // load bit pattern
+                  "not       %%edx            \n\t" // unmask => mask for later
+                  "psubb     %%mm6, %%mm6     \n\t" // zero mm6
+                  "punpcklbw %%mm7, %%mm7     \n\t"
+                  "punpcklwd %%mm7, %%mm7     \n\t"
+                  "punpckldq %%mm7, %%mm7     \n\t" // fill reg with 8 masks
+
+                  LOAD_GOT_rbp
+                  "movq   " MASK8_0 ", %%mm0  \n\t" // _mask8_0 -> mm0
+                  RESTORE_rbp
+
+                  "pand      %%mm7, %%mm0     \n\t" // nonzero if keep byte
+                  "pcmpeqb   %%mm6, %%mm0     \n\t" // zeros->1s, v versa
+
+// preload        "movl      len, %%ecx       \n\t" // load length of line
+// preload        "movl      srcptr, %3       \n\t" // load source
+// preload        "movl      dstptr, %4       \n\t" // load dest
+
+                  "cmpl      $0, %%ecx        \n\t" // len == 0 ?
+                  "je        mainloop8end     \n\t"
+
+                "mainloop8:                   \n\t"
+                  "movq      (%3), %%mm4      \n\t" // *srcptr
+                  "pand      %%mm0, %%mm4     \n\t"
+                  "movq      %%mm0, %%mm6     \n\t"
+                  "pandn     (%4), %%mm6      \n\t" // *dstptr
+                  "por       %%mm6, %%mm4     \n\t"
+                  "movq      %%mm4, (%4)      \n\t"
+                  "add       $8, %3           \n\t" // inc by 8 bytes processed
+                  "add       $8, %4           \n\t"
+                  "subl      $8, %%ecx        \n\t" // dec by 8 pixels processed
+                  "ja        mainloop8        \n\t"
+
+                "mainloop8end:                \n\t"
+// preload        "movl      diff, %%ecx      \n\t" // (diff is in eax)
+                  "movl      %%eax, %%ecx     \n\t"
+                  "cmpl      $0, %%ecx        \n\t"
+                  "jz        end8             \n\t"
+// preload        "movl      mask, %%edx      \n\t"
+                  "sall      $24, %%edx       \n\t" // make low byte, high byte
+
+                "secondloop8:                 \n\t"
+                  "sall      %%edx            \n\t" // move high bit to CF
+                  "jnc       skip8            \n\t" // if CF = 0
+                  "movb      (%3), %%al       \n\t"
+                  "movb      %%al, (%4)       \n\t"
+
+                "skip8:                       \n\t"
+                  "inc       %3               \n\t"
+                  "inc       %4               \n\t"
+                  "decl      %%ecx            \n\t"
+                  "jnz       secondloop8      \n\t"
+
+                "end8:                        \n\t"
+                  "EMMS                       \n\t" // DONE
+
+                  : "=a" (dummy_value_a),           // output regs (dummy)
+                    "=d" (dummy_value_d),
+                    "=c" (dummy_value_c),
+                    "=S" (dummy_value_S),
+                    "=D" (dummy_value_D)
+
+                  : "0" (diff),        // eax       // input regs
+                    "1" (mask),        // edx
+                    "2" (len),         // ecx
+// was (unmask)     "b"    RESERVED    // ebx       // Global Offset Table idx
+                    "3" (srcptr),      // esi/rsi
+                    "4" (dstptr)       // edi/rdi
+
+#if defined(PNG_CLOBBER_MMX_REGS_SUPPORTED)
+                  : "%mm0", "%mm4", "%mm6", "%mm7"  // clobber list
+#endif
+               );
+            }
+            else /* not _mmx_supported - use modified C routine */
+            {
+               register png_uint_32 i;
+               png_uint_32 initial_val = png_pass_start[png_ptr->pass];
+                 /* png.c:  png_pass_start[] = {0, 4, 0, 2, 0, 1, 0}; */
+               register int stride = png_pass_inc[png_ptr->pass];
+                 /* png.c:  png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1}; */
+               register int rep_bytes = png_pass_width[png_ptr->pass];
+                 /* png.c:  png_pass_width[] = {8, 4, 4, 2, 2, 1, 1}; */
+               png_uint_32 len = png_ptr->width &~7;  /* reduce to mult. of 8 */
+               int diff = (int) (png_ptr->width & 7); /* amount lost */
+               register png_uint_32 final_val = len;  /* GRR bugfix */
+
+               srcptr = png_ptr->row_buf + 1 + initial_val;
+               dstptr = row + initial_val;
+
+               for (i = initial_val; i < final_val; i += stride)
+               {
+                  png_memcpy(dstptr, srcptr, rep_bytes);
+                  srcptr += stride;
+                  dstptr += stride;
+               }
+               if (diff)  /* number of leftover pixels:  3 for pngtest */
+               {
+                  final_val += diff /* *BPP1 */ ;
+                  for (; i < final_val; i += stride)
+                  {
+                     if (rep_bytes > (int)(final_val-i))
+                        rep_bytes = (int)(final_val-i);
+                     png_memcpy(dstptr, srcptr, rep_bytes);
+                     srcptr += stride;
+                     dstptr += stride;
+                  }
+               }
+
+            } /* end of else (_mmx_supported) */
+
+            break;
+         }       /* end 8 bpp */
+
+         case 1:        /* png_ptr->row_info.pixel_depth */
+         {
+            png_bytep sp;
+            png_bytep dp;
+            int s_inc, s_start, s_end;
+            int m;
+            int shift;
+            png_uint_32 i;
+
+            sp = png_ptr->row_buf + 1;
+            dp = row;
+            m = 0x80;
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+            if (png_ptr->transformations & PNG_PACKSWAP)
+            {
+               s_start = 0;
+               s_end = 7;
+               s_inc = 1;
+            }
+            else
+#endif
+            {
+               s_start = 7;
+               s_end = 0;
+               s_inc = -1;
+            }
+
+            shift = s_start;
+
+            for (i = 0; i < png_ptr->width; i++)
+            {
+               if (m & mask)
+               {
+                  int value;
+
+                  value = (*sp >> shift) & 0x1;
+                  *dp &= (png_byte)((0x7f7f >> (7 - shift)) & 0xff);
+                  *dp |= (png_byte)(value << shift);
+               }
+
+               if (shift == s_end)
+               {
+                  shift = s_start;
+                  sp++;
+                  dp++;
+               }
+               else
+                  shift += s_inc;
+
+               if (m == 1)
+                  m = 0x80;
+               else
+                  m >>= 1;
+            }
+            break;
+         }       /* end 1 bpp */
+
+         case 2:        /* png_ptr->row_info.pixel_depth */
+         {
+            png_bytep sp;
+            png_bytep dp;
+            int s_start, s_end, s_inc;
+            int m;
+            int shift;
+            png_uint_32 i;
+            int value;
+
+            sp = png_ptr->row_buf + 1;
+            dp = row;
+            m = 0x80;
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+            if (png_ptr->transformations & PNG_PACKSWAP)
+            {
+               s_start = 0;
+               s_end = 6;
+               s_inc = 2;
+            }
+            else
+#endif
+            {
+               s_start = 6;
+               s_end = 0;
+               s_inc = -2;
+            }
+
+            shift = s_start;
+
+            for (i = 0; i < png_ptr->width; i++)
+            {
+               if (m & mask)
+               {
+                  value = (*sp >> shift) & 0x3;
+                  *dp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
+                  *dp |= (png_byte)(value << shift);
+               }
+
+               if (shift == s_end)
+               {
+                  shift = s_start;
+                  sp++;
+                  dp++;
+               }
+               else
+                  shift += s_inc;
+               if (m == 1)
+                  m = 0x80;
+               else
+                  m >>= 1;
+            }
+            break;
+         }       /* end 2 bpp */
+
+         case 4:        /* png_ptr->row_info.pixel_depth */
+         {
+            png_bytep sp;
+            png_bytep dp;
+            int s_start, s_end, s_inc;
+            int m;
+            int shift;
+            png_uint_32 i;
+            int value;
+
+            sp = png_ptr->row_buf + 1;
+            dp = row;
+            m = 0x80;
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+            if (png_ptr->transformations & PNG_PACKSWAP)
+            {
+               s_start = 0;
+               s_end = 4;
+               s_inc = 4;
+            }
+            else
+#endif
+            {
+               s_start = 4;
+               s_end = 0;
+               s_inc = -4;
+            }
+
+            shift = s_start;
+
+            for (i = 0; i < png_ptr->width; i++)
+            {
+               if (m & mask)
+               {
+                  value = (*sp >> shift) & 0xf;
+                  *dp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
+                  *dp |= (png_byte)(value << shift);
+               }
+
+               if (shift == s_end)
+               {
+                  shift = s_start;
+                  sp++;
+                  dp++;
+               }
+               else
+                  shift += s_inc;
+               if (m == 1)
+                  m = 0x80;
+               else
+                  m >>= 1;
+            }
+            break;
+         }       /* end 4 bpp */
+
+         case 16:       /* png_ptr->row_info.pixel_depth */
+         {
+            png_bytep srcptr;
+            png_bytep dstptr;
+
+#if !defined(PNG_1_0_X)
+            if (png_ptr->asm_flags & PNG_ASM_FLAG_MMX_READ_COMBINE_ROW)
+#else
+            if (_mmx_supported)
+#endif
+            {
+               png_uint_32 len;
+               int diff;
+
+               srcptr = png_ptr->row_buf + 1;
+               dstptr = row;
+               len  = png_ptr->width & ~7;          // reduce to multiple of 8
+               diff = (int) (png_ptr->width & 7);   // amount lost
+
+               __asm__ __volatile__ (
+                  "not       %%edx            \n\t" // mask => unmask
+                  "movd      %%edx, %%mm7     \n\t" // load bit pattern
+                  "not       %%edx            \n\t" // unmask => mask for later
+                  "psubb     %%mm6, %%mm6     \n\t" // zero mm6
+                  "punpcklbw %%mm7, %%mm7     \n\t"
+                  "punpcklwd %%mm7, %%mm7     \n\t"
+                  "punpckldq %%mm7, %%mm7     \n\t" // fill reg with 8 masks
+
+                  LOAD_GOT_rbp
+                  "movq   " MASK16_0 ", %%mm0 \n\t" // _mask16_0 -> mm0
+                  "movq   " MASK16_1 ", %%mm1 \n\t" // _mask16_1 -> mm1
+                  RESTORE_rbp
+
+                  "pand      %%mm7, %%mm0     \n\t"
+                  "pand      %%mm7, %%mm1     \n\t"
+
+                  "pcmpeqb   %%mm6, %%mm0     \n\t"
+                  "pcmpeqb   %%mm6, %%mm1     \n\t"
+
+// preload        "movl      len, %%ecx       \n\t" // load length of line
+// preload        "movl      srcptr, %3       \n\t" // load source
+// preload        "movl      dstptr, %4       \n\t" // load dest
+
+                  "cmpl      $0, %%ecx        \n\t"
+                  "jz        mainloop16end    \n\t"
+
+                "mainloop16:                  \n\t"
+                  "movq      (%3), %%mm4      \n\t"
+                  "pand      %%mm0, %%mm4     \n\t"
+                  "movq      %%mm0, %%mm6     \n\t"
+                  "movq      (%4), %%mm7      \n\t"
+                  "pandn     %%mm7, %%mm6     \n\t"
+                  "por       %%mm6, %%mm4     \n\t"
+                  "movq      %%mm4, (%4)      \n\t"
+
+                  "movq      8(%3), %%mm5     \n\t"
+                  "pand      %%mm1, %%mm5     \n\t"
+                  "movq      %%mm1, %%mm7     \n\t"
+                  "movq      8(%4), %%mm6     \n\t"
+                  "pandn     %%mm6, %%mm7     \n\t"
+                  "por       %%mm7, %%mm5     \n\t"
+                  "movq      %%mm5, 8(%4)     \n\t"
+
+                  "add       $16, %3          \n\t" // inc by 16 bytes processed
+                  "add       $16, %4          \n\t"
+                  "subl      $8, %%ecx        \n\t" // dec by 8 pixels processed
+                  "ja        mainloop16       \n\t"
+
+                "mainloop16end:               \n\t"
+// preload        "movl      diff, %%ecx      \n\t" // (diff is in eax)
+                  "movl      %%eax, %%ecx     \n\t"
+                  "cmpl      $0, %%ecx        \n\t"
+                  "jz        end16            \n\t"
+// preload        "movl      mask, %%edx      \n\t"
+                  "sall      $24, %%edx       \n\t" // make low byte, high byte
+
+                "secondloop16:                \n\t"
+                  "sall      %%edx            \n\t" // move high bit to CF
+                  "jnc       skip16           \n\t" // if CF = 0
+                  "movw      (%3), %%ax       \n\t"
+                  "movw      %%ax, (%4)       \n\t"
+
+                "skip16:                      \n\t"
+                  "add       $2, %3           \n\t"
+                  "add       $2, %4           \n\t"
+                  "decl      %%ecx            \n\t"
+                  "jnz       secondloop16     \n\t"
+
+                "end16:                       \n\t"
+                  "EMMS                       \n\t" // DONE
+
+                  : "=a" (dummy_value_a),           // output regs (dummy)
+                    "=d" (dummy_value_d),
+                    "=c" (dummy_value_c),
+                    "=S" (dummy_value_S),
+                    "=D" (dummy_value_D)
+
+                  : "0" (diff),        // eax       // input regs
+                    "1" (mask),        // edx
+                    "2" (len),         // ecx
+// was (unmask)     "b"    RESERVED    // ebx       // Global Offset Table idx
+                    "3" (srcptr),      // esi/rsi
+                    "4" (dstptr)       // edi/rdi
+
+#if defined(PNG_CLOBBER_MMX_REGS_SUPPORTED)
+                  : "%mm0", "%mm1", "%mm4"          // clobber list
+                  , "%mm5", "%mm6", "%mm7"
+#endif
+               );
+            }
+            else /* not _mmx_supported - use modified C routine */
+            {
+               register png_uint_32 i;
+               png_uint_32 initial_val = BPP2 * png_pass_start[png_ptr->pass];
+                 /* png.c:  png_pass_start[] = {0, 4, 0, 2, 0, 1, 0}; */
+               register int stride = BPP2 * png_pass_inc[png_ptr->pass];
+                 /* png.c:  png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1}; */
+               register int rep_bytes = BPP2 * png_pass_width[png_ptr->pass];
+                 /* png.c:  png_pass_width[] = {8, 4, 4, 2, 2, 1, 1}; */
+               png_uint_32 len = png_ptr->width &~7;  /* reduce to mult. of 8 */
+               int diff = (int) (png_ptr->width & 7); /* amount lost */
+               register png_uint_32 final_val = BPP2 * len;   /* GRR bugfix */
+
+               srcptr = png_ptr->row_buf + 1 + initial_val;
+               dstptr = row + initial_val;
+
+               for (i = initial_val; i < final_val; i += stride)
+               {
+                  png_memcpy(dstptr, srcptr, rep_bytes);
+                  srcptr += stride;
+                  dstptr += stride;
+               }
+               if (diff)  /* number of leftover pixels:  3 for pngtest */
+               {
+                  final_val += diff*BPP2;
+                  for (; i < final_val; i += stride)
+                  {
+                     if (rep_bytes > (int)(final_val-i))
+                        rep_bytes = (int)(final_val-i);
+                     png_memcpy(dstptr, srcptr, rep_bytes);
+                     srcptr += stride;
+                     dstptr += stride;
+                  }
+               }
+            } /* end of else (_mmx_supported) */
+
+            break;
+         }       /* end 16 bpp */
+
+         case 48:       /* png_ptr->row_info.pixel_depth */
+         {
+            png_bytep srcptr;
+            png_bytep dstptr;
+
+#if !defined(PNG_1_0_X)
+            if (png_ptr->asm_flags & PNG_ASM_FLAG_MMX_READ_COMBINE_ROW)
+#else
+            if (_mmx_supported)
+#endif
+            {
+               png_uint_32 len;
+               int diff;
+
+               srcptr = png_ptr->row_buf + 1;
+               dstptr = row;
+               len  = png_ptr->width & ~7;          // reduce to multiple of 8
+               diff = (int) (png_ptr->width & 7);   // amount lost
+
+               __asm__ __volatile__ (
+                  "not       %%edx            \n\t" // mask => unmask
+                  "movd      %%edx, %%mm7     \n\t" // load bit pattern
+                  "not       %%edx            \n\t" // unmask => mask for later
+                  "psubb     %%mm6, %%mm6     \n\t" // zero mm6
+                  "punpcklbw %%mm7, %%mm7     \n\t"
+                  "punpcklwd %%mm7, %%mm7     \n\t"
+                  "punpckldq %%mm7, %%mm7     \n\t" // fill reg with 8 masks
+
+                  LOAD_GOT_rbp
+                  "movq   " MASK48_0 ", %%mm0 \n\t" // _mask48_0 -> mm0
+                  "movq   " MASK48_1 ", %%mm1 \n\t" // _mask48_1 -> mm1
+                  "movq   " MASK48_2 ", %%mm2 \n\t" // _mask48_2 -> mm2
+                  "movq   " MASK48_3 ", %%mm3 \n\t" // _mask48_3 -> mm3
+                  "movq   " MASK48_4 ", %%mm4 \n\t" // _mask48_4 -> mm4
+                  "movq   " MASK48_5 ", %%mm5 \n\t" // _mask48_5 -> mm5
+                  RESTORE_rbp
+
+                  "pand      %%mm7, %%mm0     \n\t"
+                  "pand      %%mm7, %%mm1     \n\t"
+                  "pand      %%mm7, %%mm2     \n\t"
+                  "pand      %%mm7, %%mm3     \n\t"
+                  "pand      %%mm7, %%mm4     \n\t"
+                  "pand      %%mm7, %%mm5     \n\t"
+
+                  "pcmpeqb   %%mm6, %%mm0     \n\t"
+                  "pcmpeqb   %%mm6, %%mm1     \n\t"
+                  "pcmpeqb   %%mm6, %%mm2     \n\t"
+                  "pcmpeqb   %%mm6, %%mm3     \n\t"
+                  "pcmpeqb   %%mm6, %%mm4     \n\t"
+                  "pcmpeqb   %%mm6, %%mm5     \n\t"
+
+// preload        "movl      len, %%ecx       \n\t" // load length of line
+// preload        "movl      srcptr, %3       \n\t" // load source
+// preload        "movl      dstptr, %4       \n\t" // load dest
+
+                  "cmpl      $0, %%ecx        \n\t"
+                  "jz        mainloop48end    \n\t"
+
+                "mainloop48:                  \n\t"
+                  "movq      (%3), %%mm7      \n\t"
+                  "pand      %%mm0, %%mm7     \n\t"
+                  "movq      %%mm0, %%mm6     \n\t"
+                  "pandn     (%4), %%mm6      \n\t"
+                  "por       %%mm6, %%mm7     \n\t"
+                  "movq      %%mm7, (%4)      \n\t"
+
+                  "movq      8(%3), %%mm6     \n\t"
+                  "pand      %%mm1, %%mm6     \n\t"
+                  "movq      %%mm1, %%mm7     \n\t"
+                  "pandn     8(%4), %%mm7     \n\t"
+                  "por       %%mm7, %%mm6     \n\t"
+                  "movq      %%mm6, 8(%4)     \n\t"
+
+                  "movq      16(%3), %%mm6    \n\t"
+                  "pand      %%mm2, %%mm6     \n\t"
+                  "movq      %%mm2, %%mm7     \n\t"
+                  "pandn     16(%4), %%mm7    \n\t"
+                  "por       %%mm7, %%mm6     \n\t"
+                  "movq      %%mm6, 16(%4)    \n\t"
+
+                  "movq      24(%3), %%mm7    \n\t"
+                  "pand      %%mm3, %%mm7     \n\t"
+                  "movq      %%mm3, %%mm6     \n\t"
+                  "pandn     24(%4), %%mm6    \n\t"
+                  "por       %%mm6, %%mm7     \n\t"
+                  "movq      %%mm7, 24(%4)    \n\t"
+
+                  "movq      32(%3), %%mm6    \n\t"
+                  "pand      %%mm4, %%mm6     \n\t"
+                  "movq      %%mm4, %%mm7     \n\t"
+                  "pandn     32(%4), %%mm7    \n\t"
+                  "por       %%mm7, %%mm6     \n\t"
+                  "movq      %%mm6, 32(%4)    \n\t"
+
+                  "movq      40(%3), %%mm7    \n\t"
+                  "pand      %%mm5, %%mm7     \n\t"
+                  "movq      %%mm5, %%mm6     \n\t"
+                  "pandn     40(%4), %%mm6    \n\t"
+                  "por       %%mm6, %%mm7     \n\t"
+                  "movq      %%mm7, 40(%4)    \n\t"
+
+                  "add       $48, %3          \n\t" // inc by 48 bytes processed
+                  "add       $48, %4          \n\t"
+                  "subl      $8, %%ecx        \n\t" // dec by 8 pixels processed
+
+                  "ja        mainloop48       \n\t"
+
+                "mainloop48end:               \n\t"
+// preload        "movl      diff, %%ecx      \n\t" // (diff is in eax)
+                  "movl      %%eax, %%ecx     \n\t"
+                  "cmpl      $0, %%ecx        \n\t"
+                  "jz        end48            \n\t"
+// preload        "movl      mask, %%edx      \n\t"
+                  "sall      $24, %%edx       \n\t" // make low byte, high byte
+
+                "secondloop48:                \n\t"
+                  "sall      %%edx            \n\t" // move high bit to CF
+                  "jnc       skip48           \n\t" // if CF = 0
+                  "movl      (%3), %%eax      \n\t"
+                  "movl      %%eax, (%4)      \n\t"
+                  "movw      4(%3), %%ax      \n\t" // GR-P bugfix 20070717
+                  "movw      %%ax, 4(%4)      \n\t" // GR-P bugfix 20070717
+
+                "skip48:                      \n\t"
+                  "add       $6, %3           \n\t" // GR-P bugfix 20070717
+                  "add       $6, %4           \n\t" // GR-P bugfix 20070717
+                  "decl      %%ecx            \n\t"
+                  "jnz       secondloop48     \n\t"
+
+                "end48:                       \n\t"
+                  "EMMS                       \n\t" // DONE
+
+                  : "=a" (dummy_value_a),           // output regs (dummy)
+                    "=d" (dummy_value_d),
+                    "=c" (dummy_value_c),
+                    "=S" (dummy_value_S),
+                    "=D" (dummy_value_D)
+
+                  : "0" (diff),        // eax       // input regs
+                    "1" (mask),        // edx
+                    "2" (len),         // ecx
+// was (unmask)     "b"    RESERVED    // ebx       // Global Offset Table idx
+                    "3" (srcptr),      // esi/rsi
+                    "4" (dstptr)       // edi/rdi
+
+#if defined(PNG_CLOBBER_MMX_REGS_SUPPORTED)
+                  : "%mm0", "%mm1", "%mm2", "%mm3"  // clobber list
+                  , "%mm4", "%mm5", "%mm6", "%mm7"
+#endif
+               );
+            }
+            else /* not _mmx_supported - use modified C routine */
+            {
+               register png_uint_32 i;
+               png_uint_32 initial_val = BPP6 * png_pass_start[png_ptr->pass];
+                 /* png.c:  png_pass_start[] = {0, 4, 0, 2, 0, 1, 0}; */
+               register int stride = BPP6 * png_pass_inc[png_ptr->pass];
+                 /* png.c:  png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1}; */
+               register int rep_bytes = BPP6 * png_pass_width[png_ptr->pass];
+                 /* png.c:  png_pass_width[] = {8, 4, 4, 2, 2, 1, 1}; */
+               png_uint_32 len = png_ptr->width &~7;  /* reduce to mult. of 8 */
+               int diff = (int) (png_ptr->width & 7); /* amount lost */
+               register png_uint_32 final_val = BPP6 * len;   /* GRR bugfix */
+
+               srcptr = png_ptr->row_buf + 1 + initial_val;
+               dstptr = row + initial_val;
+
+               for (i = initial_val; i < final_val; i += stride)
+               {
+                  png_memcpy(dstptr, srcptr, rep_bytes);
+                  srcptr += stride;
+                  dstptr += stride;
+               }
+               if (diff)  /* number of leftover pixels:  3 for pngtest */
+               {
+                  final_val += diff*BPP6;
+                  for (; i < final_val; i += stride)
+                  {
+                     if (rep_bytes > (int)(final_val-i))
+                        rep_bytes = (int)(final_val-i);
+                     png_memcpy(dstptr, srcptr, rep_bytes);
+                     srcptr += stride;
+                     dstptr += stride;
+                  }
+               }
+            } /* end of else (_mmx_supported) */
+
+            break;
+         }       /* end 48 bpp */
+
+         case 64:       /* png_ptr->row_info.pixel_depth */
+         {
+            png_bytep srcptr;
+            png_bytep dstptr;
+            register png_uint_32 i;
+            png_uint_32 initial_val = BPP8 * png_pass_start[png_ptr->pass];
+              /* png.c:  png_pass_start[] = {0, 4, 0, 2, 0, 1, 0}; */
+            register int stride = BPP8 * png_pass_inc[png_ptr->pass];
+              /* png.c:  png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1}; */
+            register int rep_bytes = BPP8 * png_pass_width[png_ptr->pass];
+              /* png.c:  png_pass_width[] = {8, 4, 4, 2, 2, 1, 1}; */
+            png_uint_32 len = png_ptr->width &~7;  /* reduce to mult. of 8 */
+            int diff = (int) (png_ptr->width & 7); /* amount lost */
+            register png_uint_32 final_val = BPP8 * len;   /* GRR bugfix */
+
+            srcptr = png_ptr->row_buf + 1 + initial_val;
+            dstptr = row + initial_val;
+
+            for (i = initial_val; i < final_val; i += stride)
+            {
+               png_memcpy(dstptr, srcptr, rep_bytes);
+               srcptr += stride;
+               dstptr += stride;
+            }
+            if (diff)  /* number of leftover pixels:  3 for pngtest */
+            {
+               final_val += diff*BPP8;
+               for (; i < final_val; i += stride)
+               {
+                  if (rep_bytes > (int)(final_val-i))
+                     rep_bytes = (int)(final_val-i);
+                  png_memcpy(dstptr, srcptr, rep_bytes);
+                  srcptr += stride;
+                  dstptr += stride;
+               }
+            }
+
+            break;
+         }       /* end 64 bpp */
+
+         default: /* png_ptr->row_info.pixel_depth != 1,2,4,8,16,24,32,48,64 */
+         {
+            // ERROR:  SHOULD NEVER BE REACHED
+#if defined(PNG_DEBUG)
+            png_debug(1, "Internal libpng logic error (GCC "
+              "png_combine_row() pixel_depth)\n");
+#endif
+            break;
+         }
+      } /* end switch (png_ptr->row_info.pixel_depth) */
+
+   } /* end if (non-trivial mask) */
+
+} /* end png_combine_row() */
+
+#endif /* PNG_HAVE_MMX_COMBINE_ROW */
+
+
+
+
+/*===========================================================================*/
+/*                                                                           */
+/*                 P N G _ D O _ R E A D _ I N T E R L A C E                 */
+/*                                                                           */
+/*===========================================================================*/
+
+#if defined(PNG_READ_INTERLACING_SUPPORTED)
+#if defined(PNG_HAVE_MMX_READ_INTERLACE)
+
+/* png_do_read_interlace() is called after any 16-bit to 8-bit conversion
+ * has taken place.  [GRR: what other steps come before and/or after?]
+ */
+
+void /* PRIVATE */
+png_do_read_interlace(png_structp png_ptr)
+{
+   png_row_infop row_info = &(png_ptr->row_info);
+   png_bytep row = png_ptr->row_buf + 1;
+   int pass = png_ptr->pass;
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+   png_uint_32 transformations = png_ptr->transformations;
+#endif
+
+   png_debug(1, "in png_do_read_interlace (pnggccrd.c)\n");
+
+   if (_mmx_supported == 2) {
+#if !defined(PNG_1_0_X)
+       /* this should have happened in png_init_mmx_flags() already */
+       png_warning(png_ptr, "asm_flags may not have been initialized");
+#endif
+       png_mmx_support();
+   }
+
+   if (row != NULL && row_info != NULL)
+   {
+      png_uint_32 final_width;
+
+      final_width = row_info->width * png_pass_inc[pass];
+
+      switch (row_info->pixel_depth)
+      {
+         case 1:
+         {
+            png_bytep sp, dp;
+            int sshift, dshift;
+            int s_start, s_end, s_inc;
+            png_byte v;
+            png_uint_32 i;
+            int j;
+
+            sp = row + (png_size_t)((row_info->width - 1) >> 3);
+            dp = row + (png_size_t)((final_width - 1) >> 3);
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+            if (transformations & PNG_PACKSWAP)
+            {
+               sshift = (int)((row_info->width + 7) & 7);
+               dshift = (int)((final_width + 7) & 7);
+               s_start = 7;
+               s_end = 0;
+               s_inc = -1;
+            }
+            else
+#endif
+            {
+               sshift = 7 - (int)((row_info->width + 7) & 7);
+               dshift = 7 - (int)((final_width + 7) & 7);
+               s_start = 0;
+               s_end = 7;
+               s_inc = 1;
+            }
+
+            for (i = row_info->width; i; i--)
+            {
+               v = (png_byte)((*sp >> sshift) & 0x1);
+               for (j = 0; j < png_pass_inc[pass]; j++)
+               {
+                  *dp &= (png_byte)((0x7f7f >> (7 - dshift)) & 0xff);
+                  *dp |= (png_byte)(v << dshift);
+                  if (dshift == s_end)
+                  {
+                     dshift = s_start;
+                     dp--;
+                  }
+                  else
+                     dshift += s_inc;
+               }
+               if (sshift == s_end)
+               {
+                  sshift = s_start;
+                  sp--;
+               }
+               else
+                  sshift += s_inc;
+            }
+            break;
+         }
+
+         case 2:
+         {
+            png_bytep sp, dp;
+            int sshift, dshift;
+            int s_start, s_end, s_inc;
+            png_uint_32 i;
+
+            sp = row + (png_size_t)((row_info->width - 1) >> 2);
+            dp = row + (png_size_t)((final_width - 1) >> 2);
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+            if (transformations & PNG_PACKSWAP)
+            {
+               sshift = (png_size_t)(((row_info->width + 3) & 3) << 1);
+               dshift = (png_size_t)(((final_width + 3) & 3) << 1);
+               s_start = 6;
+               s_end = 0;
+               s_inc = -2;
+            }
+            else
+#endif
+            {
+               sshift = (png_size_t)((3 - ((row_info->width + 3) & 3)) << 1);
+               dshift = (png_size_t)((3 - ((final_width + 3) & 3)) << 1);
+               s_start = 0;
+               s_end = 6;
+               s_inc = 2;
+            }
+
+            for (i = row_info->width; i; i--)
+            {
+               png_byte v;
+               int j;
+
+               v = (png_byte)((*sp >> sshift) & 0x3);
+               for (j = 0; j < png_pass_inc[pass]; j++)
+               {
+                  *dp &= (png_byte)((0x3f3f >> (6 - dshift)) & 0xff);
+                  *dp |= (png_byte)(v << dshift);
+                  if (dshift == s_end)
+                  {
+                     dshift = s_start;
+                     dp--;
+                  }
+                  else
+                     dshift += s_inc;
+               }
+               if (sshift == s_end)
+               {
+                  sshift = s_start;
+                  sp--;
+               }
+               else
+                  sshift += s_inc;
+            }
+            break;
+         }
+
+         case 4:
+         {
+            png_bytep sp, dp;
+            int sshift, dshift;
+            int s_start, s_end, s_inc;
+            png_uint_32 i;
+
+            sp = row + (png_size_t)((row_info->width - 1) >> 1);
+            dp = row + (png_size_t)((final_width - 1) >> 1);
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+            if (transformations & PNG_PACKSWAP)
+            {
+               sshift = (png_size_t)(((row_info->width + 1) & 1) << 2);
+               dshift = (png_size_t)(((final_width + 1) & 1) << 2);
+               s_start = 4;
+               s_end = 0;
+               s_inc = -4;
+            }
+            else
+#endif
+            {
+               sshift = (png_size_t)((1 - ((row_info->width + 1) & 1)) << 2);
+               dshift = (png_size_t)((1 - ((final_width + 1) & 1)) << 2);
+               s_start = 0;
+               s_end = 4;
+               s_inc = 4;
+            }
+
+            for (i = row_info->width; i; i--)
+            {
+               png_byte v;
+               int j;
+
+               v = (png_byte)((*sp >> sshift) & 0xf);
+               for (j = 0; j < png_pass_inc[pass]; j++)
+               {
+                  *dp &= (png_byte)((0xf0f >> (4 - dshift)) & 0xff);
+                  *dp |= (png_byte)(v << dshift);
+                  if (dshift == s_end)
+                  {
+                     dshift = s_start;
+                     dp--;
+                  }
+                  else
+                     dshift += s_inc;
+               }
+               if (sshift == s_end)
+               {
+                  sshift = s_start;
+                  sp--;
+               }
+               else
+                  sshift += s_inc;
+            }
+            break;
+         }
+
+       /*====================================================================*/
+
+         default: /* 8-bit or larger (this is where the routine is modified) */
+         {
+            png_bytep sptr, dp;
+            png_uint_32 i;
+            png_size_t pixel_bytes;
+            int width = (int)row_info->width;
+
+            pixel_bytes = (row_info->pixel_depth >> 3);
+
+            /* point sptr at the last pixel in the pre-expanded row: */
+            sptr = row + (width - 1) * pixel_bytes;
+
+            /* point dp at the last pixel position in the expanded row: */
+            dp = row + (final_width - 1) * pixel_bytes;
+
+            /* New code by Nirav Chhatrapati - Intel Corporation */
+
+#if !defined(PNG_1_0_X)
+            if (png_ptr->asm_flags & PNG_ASM_FLAG_MMX_READ_INTERLACE)
+#else
+            if (_mmx_supported)
+#endif
+            {
+               int dummy_value_c;        // fix 'forbidden register spilled'
+               png_bytep dummy_value_S;
+               png_bytep dummy_value_D;
+               png_bytep dummy_value_a;
+               png_bytep dummy_value_d;
+
+               //--------------------------------------------------------------
+               if (pixel_bytes == BPP3)
+               {
+                  if (((pass == 4) || (pass == 5)) && width)
+                  {
+                     int width_mmx = ((width >> 1) << 1) - 8;   // GRR:  huh?
+                     if (width_mmx < 0)
+                         width_mmx = 0;
+                     width -= width_mmx;        // 8 or 9 pix, 24 or 27 bytes
+                     if (width_mmx)
+                     {
+                        // png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
+                        // sptr points at last pixel in pre-expanded row
+                        // dp points at last pixel position in expanded row
+                        __asm__ __volatile__ (
+                           "sub  $3, %1             \n\t"
+                           "sub  $9, %2             \n\t"
+                                        // (png_pass_inc[pass] + 1)*pixel_bytes
+
+                        ".loop3_pass4:              \n\t"
+                           "movq (%1), %%mm0        \n\t" // x x 5 4 3 2 1 0
+                           "movq %%mm0, %%mm1       \n\t" // x x 5 4 3 2 1 0
+                           "movq %%mm0, %%mm2       \n\t" // x x 5 4 3 2 1 0
+                           "psllq $24, %%mm0        \n\t" // 4 3 2 1 0 z z z
+                           "pand (%3), %%mm1        \n\t" // z z z z z 2 1 0
+                           "psrlq $24, %%mm2        \n\t" // z z z x x 5 4 3
+                           "por %%mm1, %%mm0        \n\t" // 4 3 2 1 0 2 1 0
+                           "movq %%mm2, %%mm3       \n\t" // z z z x x 5 4 3
+                           "psllq $8, %%mm2         \n\t" // z z x x 5 4 3 z
+                           "movq %%mm0, (%2)        \n\t"
+                           "psrlq $16, %%mm3        \n\t" // z z z z z x x 5
+                           "pand (%4), %%mm3        \n\t" // z z z z z z z 5
+                           "por %%mm3, %%mm2        \n\t" // z z x x 5 4 3 5
+                           "sub  $6, %1             \n\t"
+                           "movd %%mm2, 8(%2)       \n\t"
+                           "sub  $12, %2            \n\t"
+                           "subl $2, %%ecx          \n\t"
+                           "jnz .loop3_pass4        \n\t"
+                           "EMMS                    \n\t" // DONE
+
+                           : "=c" (dummy_value_c),        // output regs (dummy)
+                             "=S" (dummy_value_S),
+                             "=D" (dummy_value_D),
+                             "=a" (dummy_value_a),
+                             "=d" (dummy_value_d)
+
+                           : "0" (width_mmx),     // ecx  // input regs
+                             "1" (sptr),          // esi/rsi
+                             "2" (dp),            // edi/rdi
+#if defined(PNG_x86_64_USE_GOTPCREL)     // formerly _const4 and _const6:
+                             "3" (&_c64._amask5_3_0), // (0x0000000000FFFFFFLL)
+                             "4" (&_c64._amask7_1_0)  // (0x00000000000000FFLL)
+#else
+                             "3" (&_amask5_3_0),  // eax (0x0000000000FFFFFFLL)
+                             "4" (&_amask7_1_0)   // edx (0x00000000000000FFLL)
+#endif
+
+#if defined(PNG_CLOBBER_MMX_REGS_SUPPORTED)
+                           : "%mm0", "%mm1"               // clobber list
+                           , "%mm2", "%mm3"
+#endif
+                        );
+                     }
+
+                     sptr -= width_mmx*BPP3;
+                     dp -= width_mmx*2*BPP3;
+                     for (i = width; i; i--)
+                     {
+                        png_byte v[8];
+                        int j;
+
+                        png_memcpy(v, sptr, BPP3);
+                        for (j = 0; j < png_pass_inc[pass]; j++)
+                        {
+                           png_memcpy(dp, v, BPP3);
+                           dp -= BPP3;
+                        }
+                        sptr -= BPP3;
+                     }
+                  }
+                  else if (((pass == 2) || (pass == 3)) && width)
+                  {
+                     __asm__ __volatile__ (
+                        "sub  $9, %2             \n\t"
+                                     // (png_pass_inc[pass] - 1)*pixel_bytes
+
+                     ".loop3_pass2:              \n\t"
+                        "movd (%1), %%mm0        \n\t" // x x x x x 2 1 0
+                        "pand (%3), %%mm0        \n\t" // z z z z z 2 1 0
+                        "movq %%mm0, %%mm1       \n\t" // z z z z z 2 1 0
+                        "psllq $16, %%mm0        \n\t" // z z z 2 1 0 z z
+                        "movq %%mm0, %%mm2       \n\t" // z z z 2 1 0 z z
+                        "psllq $24, %%mm0        \n\t" // 2 1 0 z z z z z
+                        "psrlq $8, %%mm1         \n\t" // z z z z z z 2 1
+                        "por %%mm2, %%mm0        \n\t" // 2 1 0 2 1 0 z z
+                        "por %%mm1, %%mm0        \n\t" // 2 1 0 2 1 0 2 1
+                        "movq %%mm0, 4(%2)       \n\t"
+                        "psrlq $16, %%mm0        \n\t" // z z 2 1 0 2 1 0
+                        "sub  $3, %1             \n\t"
+                        "movd %%mm0, (%2)        \n\t"
+                        "sub  $12, %2            \n\t"
+                        "decl %%ecx              \n\t"
+                        "jnz .loop3_pass2        \n\t"
+                        "EMMS                    \n\t" // DONE
+
+                        : "=c" (dummy_value_c),        // output regs (dummy)
+                          "=S" (dummy_value_S),
+                          "=D" (dummy_value_D),
+                          "=a" (dummy_value_a)
+
+                        : "0" (width),         // ecx  // input regs
+                          "1" (sptr),          // esi/rsi
+                          "2" (dp),            // edi/rdi
+#if defined(PNG_x86_64_USE_GOTPCREL)           // formerly _const4:
+                          "3" (&_c64._amask5_3_0)  // (0x0000000000FFFFFFLL)
+#else
+                          "3" (&_amask5_3_0)   // eax (0x0000000000FFFFFFLL)
+#endif
+
+#if defined(CLOBBER_MMX_REGS_SUPPORTED)
+                        : "%mm0", "%mm1", "%mm2"       // clobber list
+#endif
+                     );
+                  }
+                  else if (width)  // && ((pass == 0) || (pass == 1))
+                  {
+                     __asm__ __volatile__ (
+                        "sub  $21, %2            \n\t"
+                                     // (png_pass_inc[pass] - 1)*pixel_bytes
+
+                     ".loop3_pass0:              \n\t"
+                        "movd (%1), %%mm0        \n\t" // x x x x x 2 1 0
+                        "pand (%3), %%mm0        \n\t" // z z z z z 2 1 0
+                        "movq %%mm0, %%mm1       \n\t" // z z z z z 2 1 0
+                        "psllq $16, %%mm0        \n\t" // z z z 2 1 0 z z
+                        "movq %%mm0, %%mm2       \n\t" // z z z 2 1 0 z z
+                        "psllq $24, %%mm0        \n\t" // 2 1 0 z z z z z
+                        "psrlq $8, %%mm1         \n\t" // z z z z z z 2 1
+                        "por %%mm2, %%mm0        \n\t" // 2 1 0 2 1 0 z z
+                        "por %%mm1, %%mm0        \n\t" // 2 1 0 2 1 0 2 1
+                        "movq %%mm0, %%mm3       \n\t" // 2 1 0 2 1 0 2 1
+                        "psllq $16, %%mm0        \n\t" // 0 2 1 0 2 1 z z
+                        "movq %%mm3, %%mm4       \n\t" // 2 1 0 2 1 0 2 1
+                        "punpckhdq %%mm0, %%mm3  \n\t" // 0 2 1 0 2 1 0 2
+                        "movq %%mm4, 16(%2)      \n\t"
+                        "psrlq $32, %%mm0        \n\t" // z z z z 0 2 1 0
+                        "movq %%mm3, 8(%2)       \n\t"
+                        "punpckldq %%mm4, %%mm0  \n\t" // 1 0 2 1 0 2 1 0
+                        "sub  $3, %1             \n\t"
+                        "movq %%mm0, (%2)        \n\t"
+                        "sub  $24, %2            \n\t"
+                        "decl %%ecx              \n\t"
+                        "jnz .loop3_pass0        \n\t"
+                        "EMMS                    \n\t" // DONE
+
+                        : "=c" (dummy_value_c),        // output regs (dummy)
+                          "=S" (dummy_value_S),
+                          "=D" (dummy_value_D),
+                          "=a" (dummy_value_a)
+
+                        : "0" (width),         // ecx  // input regs
+                          "1" (sptr),          // esi/rsi
+                          "2" (dp),            // edi/rdi
+#if defined(PNG_x86_64_USE_GOTPCREL)           // formerly _const4:
+                          "3" (&_c64._amask5_3_0)  // (0x0000000000FFFFFFLL)
+#else
+                          "3" (&_amask5_3_0)   // eax (0x0000000000FFFFFFLL)
+#endif
+
+#if defined(PNG_CLOBBER_MMX_REGS_SUPPORTED)
+                        : "%mm0", "%mm1", "%mm2"       // clobber list
+                        , "%mm3", "%mm4"
+#endif
+                     );
+                  }
+               } /* end of pixel_bytes == 3 */
+
+               //--------------------------------------------------------------
+               else if (pixel_bytes == BPP4)
+               {
+                  if (((pass == 4) || (pass == 5)) && width)
+                  {
+                     int width_mmx = ((width >> 1) << 1) ;
+                     width -= width_mmx;        // 0,1 pixels => 0,4 bytes
+                     if (width_mmx)
+                     {
+                        __asm__ __volatile__ (
+                           "sub  $4, %1             \n\t"
+                           "sub  $12, %2            \n\t"
+
+                        ".loop4_pass4:              \n\t"
+                           "movq (%1), %%mm0        \n\t" // 7 6 5 4 3 2 1 0
+                           "movq %%mm0, %%mm1       \n\t" // 7 6 5 4 3 2 1 0
+                           "punpckldq %%mm0, %%mm0  \n\t" // 3 2 1 0 3 2 1 0
+                           "punpckhdq %%mm1, %%mm1  \n\t" // 7 6 5 4 7 6 5 4
+                           "movq %%mm0, (%2)        \n\t"
+                           "sub  $8, %1             \n\t"
+                           "movq %%mm1, 8(%2)       \n\t"
+                           "sub  $16, %2            \n\t"
+                           "subl $2, %%ecx          \n\t"
+                           "jnz .loop4_pass4        \n\t"
+                           "EMMS                    \n\t" // DONE
+
+                           : "=c" (dummy_value_c),        // output regs (dummy)
+                             "=S" (dummy_value_S),
+                             "=D" (dummy_value_D)
+
+                           : "0" (width_mmx),     // ecx  // input regs
+                             "1" (sptr),          // esi/rsi
+                             "2" (dp)             // edi/rdi
+
+#if defined(CLOBBER_MMX_REGS_SUPPORTED)
+                           : "%mm0", "%mm1"               // clobber list
+#endif
+                        );
+                     }
+
+                     sptr -= (width_mmx*BPP4 - BPP4); // sign fixed
+                     dp -= (width_mmx*2*BPP4 - BPP4); // sign fixed
+                     for (i = width; i; i--)
+                     {
+                        png_byte v[8];
+                        int j;
+                        sptr -= BPP4;
+                        png_memcpy(v, sptr, BPP4);
+                        for (j = 0; j < png_pass_inc[pass]; j++)
+                        {
+                           dp -= BPP4;
+                           png_memcpy(dp, v, BPP4);
+                        }
+                     }
+                  }
+                  else if (((pass == 2) || (pass == 3)) && width)
+                  {
+                     int width_mmx = ((width >> 1) << 1);
+                     width -= width_mmx;        // 0,1 pixels => 0,4 bytes
+                     if (width_mmx)
+                     {
+                        __asm__ __volatile__ (
+                           "sub  $4, %1             \n\t"
+                           "sub  $28, %2            \n\t"
+
+                        ".loop4_pass2:              \n\t"
+                           "movq (%1), %%mm0        \n\t" // 7 6 5 4 3 2 1 0
+                           "movq %%mm0, %%mm1       \n\t" // 7 6 5 4 3 2 1 0
+                           "punpckldq %%mm0, %%mm0  \n\t" // 3 2 1 0 3 2 1 0
+                           "punpckhdq %%mm1, %%mm1  \n\t" // 7 6 5 4 7 6 5 4
+                           "movq %%mm0, (%2)        \n\t"
+                           "movq %%mm0, 8(%2)       \n\t"
+                           "movq %%mm1, 16(%2)      \n\t"
+                           "movq %%mm1, 24(%2)      \n\t"
+                           "sub  $8, %1             \n\t"
+                           "sub  $32, %2            \n\t"
+                           "subl $2, %%ecx          \n\t"
+                           "jnz .loop4_pass2        \n\t"
+                           "EMMS                    \n\t" // DONE
+
+                           : "=c" (dummy_value_c),        // output regs (dummy)
+                             "=S" (dummy_value_S),
+                             "=D" (dummy_value_D)
+
+                           : "0" (width_mmx),     // ecx  // input regs
+                             "1" (sptr),          // esi/rsi
+                             "2" (dp)             // edi/rdi
+
+#if defined(CLOBBER_MMX_REGS_SUPPORTED)
+                           : "%mm0", "%mm1"               // clobber list
+#endif
+                        );
+                     }
+
+                     sptr -= (width_mmx*4 - 4); // sign fixed
+                     dp -= (width_mmx*16 - 4);  // sign fixed
+                     for (i = width; i; i--)
+                     {
+                        png_byte v[8];
+                        int j;
+                        sptr -= 4;
+                        png_memcpy(v, sptr, 4);
+                        for (j = 0; j < png_pass_inc[pass]; j++)
+                        {
+                           dp -= 4;
+                           png_memcpy(dp, v, 4);
+                        }
+                     }
+                  }
+                  else if (width)  // && ((pass == 0) || (pass == 1))
+                  {
+                     int width_mmx = ((width >> 1) << 1);
+                     width -= width_mmx;        // 0,1 pixels => 0,4 bytes
+                     if (width_mmx)
+                     {
+                        __asm__ __volatile__ (
+                           "sub  $4, %1             \n\t"
+                           "sub  $60, %2            \n\t"
+
+                        ".loop4_pass0:              \n\t"
+                           "movq (%1), %%mm0        \n\t" // 7 6 5 4 3 2 1 0
+                           "movq %%mm0, %%mm1       \n\t" // 7 6 5 4 3 2 1 0
+                           "punpckldq %%mm0, %%mm0  \n\t" // 3 2 1 0 3 2 1 0
+                           "punpckhdq %%mm1, %%mm1  \n\t" // 7 6 5 4 7 6 5 4
+                           "movq %%mm0, (%2)        \n\t"
+                           "movq %%mm0, 8(%2)       \n\t"
+                           "movq %%mm0, 16(%2)      \n\t"
+                           "movq %%mm0, 24(%2)      \n\t"
+                           "movq %%mm1, 32(%2)      \n\t"
+                           "movq %%mm1, 40(%2)      \n\t"
+                           "movq %%mm1, 48(%2)      \n\t"
+                           "sub  $8, %1             \n\t"
+                           "movq %%mm1, 56(%2)      \n\t"
+                           "sub  $64, %2            \n\t"
+                           "subl $2, %%ecx          \n\t"
+                           "jnz .loop4_pass0        \n\t"
+                           "EMMS                    \n\t" // DONE
+
+                           : "=c" (dummy_value_c),        // output regs (dummy)
+                             "=S" (dummy_value_S),
+                             "=D" (dummy_value_D)
+
+                           : "0" (width_mmx),     // ecx  // input regs
+                             "1" (sptr),          // esi/rsi
+                             "2" (dp)             // edi/rdi
+
+#if defined(PNG_CLOBBER_MMX_REGS_SUPPORTED)
+                           : "%mm0", "%mm1"               // clobber list
+#endif
+                        );
+                     }
+
+                     sptr -= (width_mmx*4 - 4); // sign fixed
+                     dp -= (width_mmx*32 - 4);  // sign fixed
+                     for (i = width; i; i--)
+                     {
+                        png_byte v[8];
+                        int j;
+                        sptr -= 4;
+                        png_memcpy(v, sptr, 4);
+                        for (j = 0; j < png_pass_inc[pass]; j++)
+                        {
+                           dp -= 4;
+                           png_memcpy(dp, v, 4);
+                        }
+                     }
+                  }
+               } /* end of pixel_bytes == 4 */
+
+               //--------------------------------------------------------------
+               else if (pixel_bytes == 1)
+               {
+                  if (((pass == 4) || (pass == 5)) && width)
+                  {
+                     int width_mmx = ((width >> 3) << 3);
+                     width -= width_mmx;        // 0-3 pixels => 0-3 bytes
+                     if (width_mmx)
+                     {
+                        __asm__ __volatile__ (
+                           "sub  $7, %1             \n\t"
+                           "sub  $15, %2            \n\t"
+
+                        ".loop1_pass4:              \n\t"
+                           "movq (%1), %%mm0        \n\t" // 7 6 5 4 3 2 1 0
+                           "movq %%mm0, %%mm1       \n\t" // 7 6 5 4 3 2 1 0
+                           "punpcklbw %%mm0, %%mm0  \n\t" // 3 3 2 2 1 1 0 0
+                           "punpckhbw %%mm1, %%mm1  \n\t" // 7 7 6 6 5 5 4 4
+                           "movq %%mm1, 8(%2)       \n\t"
+                           "sub  $8, %1             \n\t"
+                           "movq %%mm0, (%2)        \n\t"
+                           "sub  $16, %2            \n\t"
+                           "subl $8, %%ecx          \n\t"
+                           "jnz .loop1_pass4        \n\t"
+                           "EMMS                    \n\t" // DONE
+
+                           : "=c" (dummy_value_c),        // output regs (dummy)
+                             "=S" (dummy_value_S),
+                             "=D" (dummy_value_D)
+
+                           : "0" (width_mmx),     // ecx  // input regs
+                             "1" (sptr),          // esi/rsi
+                             "2" (dp)             // edi/rdi
+
+#if defined(PNG_CLOBBER_MMX_REGS_SUPPORTED)
+                           : "%mm0", "%mm1"               // clobber list
+#endif
+                        );
+                     }
+
+                     sptr -= width_mmx;
+                     dp -= width_mmx*2;
+                     for (i = width; i; i--)
+                     {
+                        int j;
+
+                        for (j = 0; j < png_pass_inc[pass]; j++)
+                        {
+                           *dp-- = *sptr;
+                        }
+                        --sptr;
+                     }
+                  }
+                  else if (((pass == 2) || (pass == 3)) && width)
+                  {
+                     int width_mmx = ((width >> 2) << 2);
+                     width -= width_mmx;        // 0-3 pixels => 0-3 bytes
+                     if (width_mmx)
+                     {
+                        __asm__ __volatile__ (
+                           "sub  $3, %1             \n\t"
+                           "sub  $15, %2            \n\t"
+
+                        ".loop1_pass2:              \n\t"
+                           "movd (%1), %%mm0        \n\t" // x x x x 3 2 1 0
+                           "punpcklbw %%mm0, %%mm0  \n\t" // 3 3 2 2 1 1 0 0
+                           "movq %%mm0, %%mm1       \n\t" // 3 3 2 2 1 1 0 0
+                           "punpcklwd %%mm0, %%mm0  \n\t" // 1 1 1 1 0 0 0 0
+                           "punpckhwd %%mm1, %%mm1  \n\t" // 3 3 3 3 2 2 2 2
+                           "movq %%mm0, (%2)        \n\t"
+                           "sub  $4, %1             \n\t"
+                           "movq %%mm1, 8(%2)       \n\t"
+                           "sub  $16, %2            \n\t"
+                           "subl $4, %%ecx          \n\t"
+                           "jnz .loop1_pass2        \n\t"
+                           "EMMS                    \n\t" // DONE
+
+                           : "=c" (dummy_value_c),        // output regs (dummy)
+                             "=S" (dummy_value_S),
+                             "=D" (dummy_value_D)
+
+                           : "0" (width_mmx),     // ecx  // input regs
+                             "1" (sptr),          // esi/rsi
+                             "2" (dp)             // edi/rdi
+
+#if defined(PNG_CLOBBER_MMX_REGS_SUPPORTED)
+                           : "%mm0", "%mm1"               // clobber list
+#endif
+                        );
+                     }
+
+                     sptr -= width_mmx;
+                     dp -= width_mmx*4;
+                     for (i = width; i; i--)
+                     {
+                        int j;
+
+                        for (j = 0; j < png_pass_inc[pass]; j++)
+                        {
+                           *dp-- = *sptr;
+                        }
+                        --sptr;
+                     }
+                  }
+                  else if (width)  // && ((pass == 0) || (pass == 1))
+                  {
+                     int width_mmx = ((width >> 2) << 2);
+                     width -= width_mmx;        // 0-3 pixels => 0-3 bytes
+                     if (width_mmx)
+                     {
+                        __asm__ __volatile__ (
+                           "sub  $3, %1             \n\t"
+                           "sub  $31, %2            \n\t"
+
+                        ".loop1_pass0:              \n\t"
+                           "movd (%1), %%mm0        \n\t" // x x x x 3 2 1 0
+                           "movq %%mm0, %%mm1       \n\t" // x x x x 3 2 1 0
+                           "punpcklbw %%mm0, %%mm0  \n\t" // 3 3 2 2 1 1 0 0
+                           "movq %%mm0, %%mm2       \n\t" // 3 3 2 2 1 1 0 0
+                           "punpcklwd %%mm0, %%mm0  \n\t" // 1 1 1 1 0 0 0 0
+                           "movq %%mm0, %%mm3       \n\t" // 1 1 1 1 0 0 0 0
+                           "punpckldq %%mm0, %%mm0  \n\t" // 0 0 0 0 0 0 0 0
+                           "punpckhdq %%mm3, %%mm3  \n\t" // 1 1 1 1 1 1 1 1
+                           "movq %%mm0, (%2)        \n\t"
+                           "punpckhwd %%mm2, %%mm2  \n\t" // 3 3 3 3 2 2 2 2
+                           "movq %%mm3, 8(%2)       \n\t"
+                           "movq %%mm2, %%mm4       \n\t" // 3 3 3 3 2 2 2 2
+                           "punpckldq %%mm2, %%mm2  \n\t" // 2 2 2 2 2 2 2 2
+                           "punpckhdq %%mm4, %%mm4  \n\t" // 3 3 3 3 3 3 3 3
+                           "movq %%mm2, 16(%2)      \n\t"
+                           "sub  $4, %1             \n\t"
+                           "movq %%mm4, 24(%2)      \n\t"
+                           "sub  $32, %2            \n\t"
+                           "subl $4, %%ecx          \n\t"
+                           "jnz .loop1_pass0        \n\t"
+                           "EMMS                    \n\t" // DONE
+
+                           : "=c" (dummy_value_c),        // output regs (dummy)
+                             "=S" (dummy_value_S),
+                             "=D" (dummy_value_D)
+
+                           : "0" (width_mmx),     // ecx  // input regs
+                             "1" (sptr),          // esi/rsi
+                             "2" (dp)             // edi/rdi
+
+#if defined(PNG_CLOBBER_MMX_REGS_SUPPORTED)
+                           : "%mm0", "%mm1", "%mm2"       // clobber list
+                           , "%mm3", "%mm4"
+#endif
+                        );
+                     }
+
+                     sptr -= width_mmx;
+                     dp -= width_mmx*8;
+                     for (i = width; i; i--)
+                     {
+                        int j;
+
+                       /* I simplified this part in version 1.0.4e
+                        * here and in several other instances where
+                        * pixel_bytes == 1  -- GR-P
+                        *
+                        * Original code:
+                        *
+                        * png_byte v[8];
+                        * png_memcpy(v, sptr, pixel_bytes);
+                        * for (j = 0; j < png_pass_inc[pass]; j++)
+                        * {
+                        *    png_memcpy(dp, v, pixel_bytes);
+                        *    dp -= pixel_bytes;
+                        * }
+                        * sptr -= pixel_bytes;
+                        *
+                        * Replacement code is in the next three lines:
+                        */
+
+                        for (j = 0; j < png_pass_inc[pass]; j++)
+                        {
+                           *dp-- = *sptr;
+                        }
+                        --sptr;
+                     }
+                  }
+               } /* end of pixel_bytes == 1 */
+
+               //--------------------------------------------------------------
+               else if (pixel_bytes == BPP2)
+               {
+                  if (((pass == 4) || (pass == 5)) && width)
+                  {
+                     int width_mmx = ((width >> 1) << 1) ;
+                     width -= width_mmx;        // 0,1 pixels => 0,2 bytes
+                     if (width_mmx)
+                     {
+                        __asm__ __volatile__ (
+                           "sub  $2, %1             \n\t"
+                           "sub  $6, %2             \n\t"
+
+                        ".loop2_pass4:              \n\t"
+                           "movd (%1), %%mm0        \n\t" // x x x x 3 2 1 0
+                           "punpcklwd %%mm0, %%mm0  \n\t" // 3 2 3 2 1 0 1 0
+                           "sub  $4, %1             \n\t"
+                           "movq %%mm0, (%2)        \n\t"
+                           "sub  $8, %2             \n\t"
+                           "subl $2, %%ecx          \n\t"
+                           "jnz .loop2_pass4        \n\t"
+                           "EMMS                    \n\t" // DONE
+
+                           : "=c" (dummy_value_c),        // output regs (dummy)
+                             "=S" (dummy_value_S),
+                             "=D" (dummy_value_D)
+
+                           : "0" (width_mmx),     // ecx  // input regs
+                             "1" (sptr),          // esi/rsi
+                             "2" (dp)             // edi/rdi
+
+#if defined(PNG_CLOBBER_MMX_REGS_SUPPORTED)
+                           : "%mm0"                       // clobber list
+#endif
+                        );
+                     }
+
+                     sptr -= (width_mmx*BPP2 - BPP2); // sign fixed
+                     dp -= (width_mmx*2*BPP2 - BPP2); // sign fixed
+                     for (i = width; i; i--)
+                     {
+                        png_byte v[8];
+                        int j;
+                        sptr -= BPP2;
+                        png_memcpy(v, sptr, BPP2);
+                        for (j = 0; j < png_pass_inc[pass]; j++)
+                        {
+                           dp -= BPP2;
+                           png_memcpy(dp, v, BPP2);
+                        }
+                     }
+                  }
+                  else if (((pass == 2) || (pass == 3)) && width)
+                  {
+                     int width_mmx = ((width >> 1) << 1) ;
+                     width -= width_mmx;        // 0,1 pixels => 0,2 bytes
+                     if (width_mmx)
+                     {
+                        __asm__ __volatile__ (
+                           "sub  $2, %1             \n\t"
+                           "sub  $14, %2            \n\t"
+
+                        ".loop2_pass2:              \n\t"
+                           "movd (%1), %%mm0        \n\t" // x x x x 3 2 1 0
+                           "punpcklwd %%mm0, %%mm0  \n\t" // 3 2 3 2 1 0 1 0
+                           "movq %%mm0, %%mm1       \n\t" // 3 2 3 2 1 0 1 0
+                           "punpckldq %%mm0, %%mm0  \n\t" // 1 0 1 0 1 0 1 0
+                           "punpckhdq %%mm1, %%mm1  \n\t" // 3 2 3 2 3 2 3 2
+                           "movq %%mm0, (%2)        \n\t"
+                           "sub  $4, %1             \n\t"
+                           "movq %%mm1, 8(%2)       \n\t"
+                           "sub  $16, %2            \n\t"
+                           "subl $2, %%ecx          \n\t"
+                           "jnz .loop2_pass2        \n\t"
+                           "EMMS                    \n\t" // DONE
+
+                           : "=c" (dummy_value_c),        // output regs (dummy)
+                             "=S" (dummy_value_S),
+                             "=D" (dummy_value_D)
+
+                           : "0" (width_mmx),     // ecx  // input regs
+                             "1" (sptr),          // esi/rsi
+                             "2" (dp)             // edi/rdi
+
+#if defined(CLOBBER_MMX_REGS_SUPPORTED)
+                           : "%mm0", "%mm1"               // clobber list
+#endif
+                        );
+                     }
+
+                     sptr -= (width_mmx*2 - 2); // sign fixed
+                     dp -= (width_mmx*8 - 2);   // sign fixed
+                     for (i = width; i; i--)
+                     {
+                        png_byte v[8];
+                        int j;
+                        sptr -= 2;
+                        png_memcpy(v, sptr, 2);
+                        for (j = 0; j < png_pass_inc[pass]; j++)
+                        {
+                           dp -= 2;
+                           png_memcpy(dp, v, 2);
+                        }
+                     }
+                  }
+                  else if (width)  // && ((pass == 0) || (pass == 1))
+                  {
+                     int width_mmx = ((width >> 1) << 1);
+                     width -= width_mmx;        // 0,1 pixels => 0,2 bytes
+                     if (width_mmx)
+                     {
+                        __asm__ __volatile__ (
+                           "sub  $2, %1             \n\t"
+                           "sub  $30, %2            \n\t"
+
+                        ".loop2_pass0:              \n\t"
+                           "movd (%1), %%mm0        \n\t" // x x x x 3 2 1 0
+                           "punpcklwd %%mm0, %%mm0  \n\t" // 3 2 3 2 1 0 1 0
+                           "movq %%mm0, %%mm1       \n\t" // 3 2 3 2 1 0 1 0
+                           "punpckldq %%mm0, %%mm0  \n\t" // 1 0 1 0 1 0 1 0
+                           "punpckhdq %%mm1, %%mm1  \n\t" // 3 2 3 2 3 2 3 2
+                           "movq %%mm0, (%2)        \n\t"
+                           "movq %%mm0, 8(%2)       \n\t"
+                           "movq %%mm1, 16(%2)      \n\t"
+                           "sub  $4, %1             \n\t"
+                           "movq %%mm1, 24(%2)      \n\t"
+                           "sub  $32, %2            \n\t"
+                           "subl $2, %%ecx          \n\t"
+                           "jnz .loop2_pass0        \n\t"
+                           "EMMS                    \n\t" // DONE
+
+                           : "=c" (dummy_value_c),        // output regs (dummy)
+                             "=S" (dummy_value_S),
+                             "=D" (dummy_value_D)
+
+                           : "0" (width_mmx),     // ecx  // input regs
+                             "1" (sptr),          // esi/rsi
+                             "2" (dp)             // edi/rdi
+
+#if defined(CLOBBER_MMX_REGS_SUPPORTED)
+                           : "%mm0", "%mm1"               // clobber list
+#endif
+                        );
+                     }
+
+                     sptr -= (width_mmx*2 - 2); // sign fixed
+                     dp -= (width_mmx*16 - 2);  // sign fixed
+                     for (i = width; i; i--)
+                     {
+                        png_byte v[8];
+                        int j;
+                        sptr -= 2;
+                        png_memcpy(v, sptr, 2);
+                        for (j = 0; j < png_pass_inc[pass]; j++)
+                        {
+                           dp -= 2;
+                           png_memcpy(dp, v, 2);
+                        }
+                     }
+                  }
+               } /* end of pixel_bytes == 2 */
+
+               //--------------------------------------------------------------
+               else if (pixel_bytes == BPP8)
+               {
+// GRR TEST:  should work, but needs testing (special 64-bit version of rpng2?)
+                  // GRR NOTE:  no need to combine passes here!
+                  if (((pass == 4) || (pass == 5)) && width)
+                  {
+                     // source is 8-byte RRGGBBAA
+                     // dest is 16-byte RRGGBBAA RRGGBBAA
+                     __asm__ __volatile__ (
+                        "sub  $8, %2             \n\t" // start of last block
+
+                     ".loop8_pass4:              \n\t"
+                        "movq (%1), %%mm0        \n\t" // 7 6 5 4 3 2 1 0
+                        "movq %%mm0, (%2)        \n\t"
+                        "sub  $8, %1             \n\t"
+                        "movq %%mm0, 8(%2)       \n\t"
+                        "sub  $16, %2            \n\t"
+                        "decl %%ecx              \n\t"
+                        "jnz .loop8_pass4        \n\t"
+                        "EMMS                    \n\t" // DONE
+
+                        : "=c" (dummy_value_c),        // output regs (dummy)
+                          "=S" (dummy_value_S),
+                          "=D" (dummy_value_D)
+
+                        : "0" (width),         // ecx  // input regs
+                          "1" (sptr),          // esi/rsi
+                          "2" (dp)             // edi/rdi
+
+#if defined(CLOBBER_MMX_REGS_SUPPORTED)
+                        : "%mm0"                       // clobber list
+#endif
+                     );
+                  }
+                  else if (((pass == 2) || (pass == 3)) && width)
+                  {
+                     // source is 8-byte RRGGBBAA
+                     // dest is 32-byte RRGGBBAA RRGGBBAA RRGGBBAA RRGGBBAA
+                     // (recall that expansion is _in place_:  sptr and dp
+                     //  both point at locations within same row buffer)
+                     __asm__ __volatile__ (
+                        "sub  $24, %2            \n\t" // start of last block
+
+                     ".loop8_pass2:              \n\t"
+                        "movq (%1), %%mm0        \n\t" // 7 6 5 4 3 2 1 0
+                        "movq %%mm0, (%2)        \n\t"
+                        "movq %%mm0, 8(%2)       \n\t"
+                        "movq %%mm0, 16(%2)      \n\t"
+                        "sub  $8, %1             \n\t"
+                        "movq %%mm0, 24(%2)      \n\t"
+                        "sub  $32, %2            \n\t"
+                        "decl %%ecx              \n\t"
+                        "jnz .loop8_pass2        \n\t"
+                        "EMMS                    \n\t" // DONE
+
+                        : "=c" (dummy_value_c),        // output regs (dummy)
+                          "=S" (dummy_value_S),
+                          "=D" (dummy_value_D)
+
+                        : "0" (width),         // ecx  // input regs
+                          "1" (sptr),          // esi/rsi
+                          "2" (dp)             // edi/rdi
+
+#if defined(PNG_CLOBBER_MMX_REGS_SUPPORTED)
+                        : "%mm0"                       // clobber list
+#endif
+                     );
+                  }
+                  else if (width)  // && ((pass == 0) || (pass == 1))
+                  {
+                     // source is 8-byte RRGGBBAA
+                     // dest is 64-byte RRGGBBAA RRGGBBAA RRGGBBAA RRGGBBAA ...
+                     __asm__ __volatile__ (
+                        "sub  $56, %2            \n\t" // start of last block
+
+                     ".loop8_pass0:              \n\t"
+                        "movq (%1), %%mm0        \n\t" // 7 6 5 4 3 2 1 0
+                        "movq %%mm0, (%2)        \n\t"
+                        "movq %%mm0, 8(%2)       \n\t"
+                        "movq %%mm0, 16(%2)      \n\t"
+                        "movq %%mm0, 24(%2)      \n\t"
+                        "movq %%mm0, 32(%2)      \n\t"
+                        "movq %%mm0, 40(%2)      \n\t"
+                        "movq %%mm0, 48(%2)      \n\t"
+                        "sub  $8, %1             \n\t"
+                        "movq %%mm0, 56(%2)      \n\t"
+                        "sub  $64, %2            \n\t"
+                        "decl %%ecx              \n\t"
+                        "jnz .loop8_pass0        \n\t"
+                        "EMMS                    \n\t" // DONE
+
+                        : "=c" (dummy_value_c),        // output regs (dummy)
+                          "=S" (dummy_value_S),
+                          "=D" (dummy_value_D)
+
+                        : "0" (width),         // ecx  // input regs
+                          "1" (sptr),          // esi/rsi
+                          "2" (dp)             // edi/rdi
+
+#if defined(PNG_CLOBBER_MMX_REGS_SUPPORTED)
+                        : "%mm0"                       // clobber list
+#endif
+                     );
+                  }
+               } /* end of pixel_bytes == 8 */
+
+               //--------------------------------------------------------------
+               else if (pixel_bytes == BPP6)   // why no MMX for this case?
+               {
+                  for (i = width; i; i--)
+                  {
+                     png_byte v[8];
+                     int j;
+                     png_memcpy(v, sptr, BPP6);
+                     for (j = 0; j < png_pass_inc[pass]; j++)
+                     {
+                        png_memcpy(dp, v, BPP6);
+                        dp -= BPP6;
+                     }
+                     sptr -= BPP6;
+                  }
+               } /* end of pixel_bytes == 6 */
+
+               //--------------------------------------------------------------
+               else
+               {
+                  // ERROR:  SHOULD NEVER BE REACHED
+#if defined(PNG_DEBUG)
+                  png_debug(1, "Internal libpng logic error (GCC "
+                    "png_do_read_interlace() _mmx_supported)\n");
+#endif
+               }
+
+            } // end of _mmx_supported ========================================
+
+            else /* MMX not supported:  use modified C code - takes advantage
+                  *   of inlining of png_memcpy for a constant */
+            {
+               if (pixel_bytes == BPP3)
+               {
+                  for (i = width; i; i--)
+                  {
+                     png_byte v[8];
+                     int j;
+                     png_memcpy(v, sptr, BPP3);
+                     for (j = 0; j < png_pass_inc[pass]; j++)
+                     {
+                        png_memcpy(dp, v, BPP3);
+                        dp -= BPP3;
+                     }
+                     sptr -= BPP3;
+                  }
+               }
+               else if (pixel_bytes == BPP4)
+               {
+                  for (i = width; i; i--)
+                  {
+                     png_byte v[8];
+                     int j;
+                     png_memcpy(v, sptr, BPP4);
+                     for (j = 0; j < png_pass_inc[pass]; j++)
+                     {
+#if defined(PNG_DEBUG) && defined(PNG_1_0_X)  // row_buf_size gone in 1.2.x
+                        if (dp < row || dp+3 > row+png_ptr->row_buf_size)
+                        {
+                           printf("dp out of bounds: row=%10p, dp=%10p, "
+                             "rp=%10p\n", row, dp, row+png_ptr->row_buf_size);
+                           printf("row_buf_size=%lu\n", png_ptr->row_buf_size);
+                        }
+#endif
+                        png_memcpy(dp, v, BPP4);
+                        dp -= BPP4;
+                     }
+                     sptr -= BPP4;
+                  }
+               }
+               else if (pixel_bytes == 1)
+               {
+                  for (i = width; i; i--)
+                  {
+                     int j;
+                     for (j = 0; j < png_pass_inc[pass]; j++)
+                     {
+                        *dp-- = *sptr;
+                     }
+                     --sptr;
+                  }
+               }
+               else if (pixel_bytes == BPP2)
+               {
+                  for (i = width; i; i--)
+                  {
+                     png_byte v[8];
+                     int j;
+                     png_memcpy(v, sptr, BPP2);
+                     for (j = 0; j < png_pass_inc[pass]; j++)
+                     {
+                        png_memcpy(dp, v, BPP2);
+                        dp -= BPP2;
+                     }
+                     sptr -= BPP2;
+                  }
+               }
+               else if (pixel_bytes == BPP6)
+               {
+                  for (i = width; i; i--)
+                  {
+                     png_byte v[8];
+                     int j;
+                     png_memcpy(v, sptr, BPP6);
+                     for (j = 0; j < png_pass_inc[pass]; j++)
+                     {
+                        png_memcpy(dp, v, BPP6);
+                        dp -= BPP6;
+                     }
+                     sptr -= BPP6;
+                  }
+               }
+               else if (pixel_bytes == BPP8)
+               {
+                  for (i = width; i; i--)
+                  {
+                     png_byte v[8];
+                     int j;
+                     png_memcpy(v, sptr, BPP8);
+                     for (j = 0; j < png_pass_inc[pass]; j++)
+                     {
+                        png_memcpy(dp, v, BPP8);
+                        dp -= BPP8;
+                     }
+                     sptr -= BPP8;
+                  }
+               }
+               else
+               {
+                  // ERROR:  SHOULD NEVER BE REACHED
+#if defined(PNG_DEBUG)
+                  png_debug(1, "Internal libpng logic error (GCC "
+                    "png_do_read_interlace() !_mmx_supported)\n");
+#endif
+               }
+
+            } /* end if (MMX not supported) */
+            break;
+         } /* end default (8-bit or larger) */
+      } /* end switch (row_info->pixel_depth) */
+
+      row_info->width = final_width;
+
+      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,final_width);
+   }
+
+} /* end png_do_read_interlace() */
+
+#endif /* PNG_HAVE_MMX_READ_INTERLACE */
+#endif /* PNG_READ_INTERLACING_SUPPORTED */
+
+
+
+#if defined(PNG_HAVE_MMX_READ_FILTER_ROW)
+#if defined(PNG_MMX_READ_FILTER_AVG_SUPPORTED)
+
+//===========================================================================//
+//                                                                           //
+//           P N G _ R E A D _ F I L T E R _ R O W _ M M X _ A V G           //
+//                                                                           //
+//===========================================================================//
+
+// Optimized code for PNG Average filter decoder
+
+static void /* PRIVATE */
+png_read_filter_row_mmx_avg(png_row_infop row_info, png_bytep row,
+                            png_bytep prev_row)
+{
+   unsigned FullLength, MMXLength;  // png_uint_32 is actually 64-bit on x86-64
+   int bpp;
+   int dummy_value_a;
+   int dummy_value_c;   // fix 'forbidden register 2 (cx) was spilled' error
+   int dummy_value_d;
+   png_bytep dummy_value_S;
+   png_bytep dummy_value_D;
+   int diff; //     __attribute__((used));
+
+   bpp = (row_info->pixel_depth + 7) >> 3;  // calc number of bytes per pixel
+   FullLength = row_info->rowbytes;         // number of bytes to filter
+
+   __asm__ __volatile__ (
+   "avg_top:                       \n\t"
+      SAVE_GOT_ebx
+      SAVE_r15
+      SAVE_ebp
+      // initialize address pointers and offset
+//pre "movl row, %5                \n\t" // edi/rdi:  ptr to Avg(x)
+      "xorl %%ebx, %%ebx           \n\t" // ebx:  x
+//pre "movl prev_row, %4           \n\t" // esi/rsi:  ptr to Prior(x)
+      "mov  %5, " PDX "            \n\t" // copy of row ptr...
+//pre "subl bpp, " PDX "           \n\t" // (bpp is preloaded into ecx)
+      "sub  " PCX "," PDX "        \n\t" // edx/rdx:  ptr to Raw(x-bpp)
+//pre "movl FullLength, %%eax      \n\t" // bring in via eax...
+      SAVE_FullLength                    // ...but store for later use
+      "xorl %%eax, %%eax           \n\t"
+
+      // Compute the Raw value for the first bpp bytes
+      //    Raw(x) = Avg(x) + (Prior(x)/2)
+   "avg_rlp:                       \n\t"
+      "movb (%4," PBX ",), %%al    \n\t" // load al with Prior(x)
+      "incl %%ebx                  \n\t"
+      "shrb %%al                   \n\t" // divide by 2
+      "addb -1(%5," PBX ",), %%al  \n\t" // add Avg(x); -1 to offset inc ebx
+//pre "cmpl bpp, %%ebx             \n\t" // (bpp is preloaded into ecx)
+      "cmpl %%ecx, %%ebx           \n\t"
+      "movb %%al, -1(%5," PBX ",)  \n\t" // write Raw(x); -1 to offset inc ebx
+      "jb avg_rlp                  \n\t" // mov does not affect flags
+
+      // get # of bytes to alignment (32-bit mask _would_ be good enough
+      // [computing delta], but 32-bit ops are zero-extended on 64-bit, argh)
+      // (if swapped edx and ebp, could do 8-bit or 16-bit mask...FIXME?)
+      "mov  %5, " PBP "            \n\t" // take start of row
+      "add  " PBX "," PBP "        \n\t" // add bpp
+      "add  $0xf, " PBP "          \n\t" // add 7+8 to incr past alignment bdry
+//    "andl $0xfffffff8, %%ebp     \n\t" // mask to alignment boundary (32-bit!)
+      CLEAR_BOTTOM_3_BITS  PBP    "\n\t" // mask to alignment boundary
+      "sub  %5, " PBP "            \n\t" // subtract row ptr again => ebp =
+      "jz avg_go                   \n\t" //  target value of ebx at alignment
+
+      "xorl %%ecx, %%ecx           \n\t"
+
+      // fix alignment
+      // Compute the Raw value for the bytes up to the alignment boundary
+      //    Raw(x) = Avg(x) + ((Raw(x-bpp) + Prior(x))/2)
+   "avg_lp1:                       \n\t"
+      "xorl %%eax, %%eax           \n\t"
+      "movb (%4," PBX ",), %%cl    \n\t" // load cl with Prior(x)
+      "movb (" PDX "," PBX ",), %%al \n\t" // load al with Raw(x-bpp)
+      "addw %%cx, %%ax             \n\t"
+      "incl %%ebx                  \n\t"
+      "shrw %%ax                   \n\t" // divide by 2
+      "addb -1(%5," PBX ",), %%al  \n\t" // add Avg(x); -1 to offset inc ebx
+      "cmpl %%ebp, %%ebx           \n\t" // check if at alignment boundary
+      "movb %%al, -1(%5," PBX ",)  \n\t" // write Raw(x); -1 to offset inc ebx
+      "jb avg_lp1                  \n\t" // repeat until at alignment boundary
+
+   "avg_go:                        \n\t"
+      RESTORE_FullLength "%%eax    \n\t" // FullLength -> eax
+      "movl %%eax, %%ecx           \n\t" // copy -> ecx
+      "subl %%ebx, %%eax           \n\t" // subtract alignment fix
+      "andl $0x00000007, %%eax     \n\t" // calc bytes over mult of 8
+      "subl %%eax, %%ecx           \n\t" // sub over-bytes from original length
+//out "movl %%ecx, MMXLength       \n\t"
+      "movl %%ebp, %%eax           \n\t" // ebp = diff, but no reg constraint(?)
+      RESTORE_ebp                        //  (could swap ebp and edx functions)
+      RESTORE_r15
+      RESTORE_GOT_ebx
+
+// "There is no way for you to specify that an input operand is modified
+// without also specifying it as an output operand."  [makes sense]
+
+// "Unless an output operand has the `&' constraint modifier, GCC may
+// allocate it in the same register as an unrelated input operand, on the
+// assumption the inputs are consumed before the outputs are produced."
+// [trying to _force_ this]
+
+// "`='   Means that this operand is write-only for this instruction:
+//        the previous value is discarded and replaced by output data."
+//        [operand == variable name, presumably]
+
+      // output regs
+      // these are operands 0-1 (originally 0-3):
+      : "=c" (MMXLength),      // %0 -> %0
+        "=a" (diff)            // %3 -> %1
+//      "=S" (dummy_value_S),  // %1 -> GONE
+//      "=D" (dummy_value_D),  // %2 -> GONE
+
+      // input regs
+      // these are operands 2-5 (originally 4-7); two of their constraints say
+      // they must go in same places as operands 0-1 (originally 0-3) above:
+      : "0" (bpp),         // %4 -> %2 ecx
+        "1" (FullLength),  // %7 -> %3 eax
+        "S" (prev_row),    // %5 -> %4 esi/rsi
+        "D" (row)          // %6 -> %5 edi/rdi
+
+      : "%edx"                           // clobber list
+        _CLOBBER_r15
+        _CLOBBER_ebp
+        _CLOBBER_GOT_ebx
+   );
+
+   // now do the math for the rest of the row
+   switch (bpp)
+   {
+      case 3:
+      {
+//       _ShiftBpp = 24;    // == 3 * 8
+//       _ShiftRem = 40;    // == 64 - 24
+
+         __asm__ __volatile__ (
+            // re-init address pointers and offset
+            LOAD_GOT_rbp
+            "movq " AMASK5_3_0 ", %%mm7    \n\t" // _amask5_3_0 -> mm7
+// preload  "movl  diff, %%ecx             \n\t" // ecx:  x = offset to
+                                                 //  alignment boundary
+            "movq " LB_CARRY_MASK ", %%mm5 \n\t" // [interleave for parallel.?]
+// preload  "movl  row, %1                 \n\t" // edi:  Avg(x)
+            "movq " HB_CLEAR_MASK ", %%mm4 \n\t" // _HBClearMask -> mm4
+// preload  "movl  prev_row, %0            \n\t" // esi:  Prior(x)
+            RESTORE_rbp
+
+            // prime the pump:  load the first Raw(x-bpp) data set
+            "movq  -8(%1," PCX ",), %%mm2 \n\t"// load previous aligned 8 bytes
+                                               // (correct pos. in loop below)
+         "avg_3lp:                        \n\t"
+            "movq  (%1," PCX ",), %%mm0   \n\t" // load mm0 with Avg(x)
+            "movq  %%mm5, %%mm3           \n\t"
+            "psrlq $40, %%mm2             \n\t" // correct position Raw(x-bpp)
+                                                // data
+            "movq  (%0," PCX ",), %%mm1   \n\t" // load mm1 with Prior(x)
+            "movq  %%mm7, %%mm6           \n\t"
+            "pand  %%mm1, %%mm3           \n\t" // get lsb for each prevrow byte
+            "psrlq $1, %%mm1              \n\t" // divide prev_row bytes by 2
+            "pand  %%mm4, %%mm1           \n\t" // clear invalid bit 7 of each
+                                                // byte
+            "paddb %%mm1, %%mm0           \n\t" // add (Prev_row/2) to Avg for
+                                                // each byte
+            // add 1st active group (Raw(x-bpp)/2) to average with LBCarry
+            "movq  %%mm3, %%mm1           \n\t" // now use mm1 for getting
+                                                // LBCarrys
+            "pand  %%mm2, %%mm1           \n\t" // get LBCarrys for each byte
+                                                // where both lsb's were == 1
+                                                // (valid only for active group)
+            "psrlq $1, %%mm2              \n\t" // divide raw bytes by 2
+            "pand  %%mm4, %%mm2           \n\t" // clear invalid bit 7 of each
+                                                // byte
+            "paddb %%mm1, %%mm2           \n\t" // add LBCarrys to Raw(x-bpp)/2
+                                                // for each byte
+            "pand  %%mm6, %%mm2           \n\t" // leave only Active Group 1
+                                                // bytes to add to Avg
+            "paddb %%mm2, %%mm0           \n\t" // add (Raw/2) + LBCarrys to
+                                                // Avg for each Active byte
+            // add 2nd active group (Raw(x-bpp)/2) to average with _LBCarry
+            "psllq $24, %%mm6             \n\t" // shift the mm6 mask to cover
+                                                // bytes 3-5
+            "movq  %%mm0, %%mm2           \n\t" // mov updated Raws to mm2
+            "psllq $24, %%mm2             \n\t" // shift data to pos. correctly
+            "movq  %%mm3, %%mm1           \n\t" // now use mm1 for getting
+                                                // LBCarrys
+            "pand  %%mm2, %%mm1           \n\t" // get LBCarrys for each byte
+                                                // where both lsb's were == 1
+                                                // (valid only for active group)
+            "psrlq $1, %%mm2              \n\t" // divide raw bytes by 2
+            "pand  %%mm4, %%mm2           \n\t" // clear invalid bit 7 of each
+                                                // byte
+            "paddb %%mm1, %%mm2           \n\t" // add LBCarrys to Raw(x-bpp)/2
+                                                // for each byte
+            "pand  %%mm6, %%mm2           \n\t" // leave only Active Group 2
+                                                // bytes to add to Avg
+            "paddb %%mm2, %%mm0           \n\t" // add (Raw/2) + LBCarrys to
+                                                // Avg for each Active byte
+
+            // add 3rd active group (Raw(x-bpp)/2) to average with _LBCarry
+            "psllq $24, %%mm6             \n\t" // shift mm6 mask to cover last
+                                                // two bytes
+            "movq  %%mm0, %%mm2           \n\t" // mov updated Raws to mm2
+            "psllq $24, %%mm2             \n\t" // shift data to pos. correctly
+                              // Data need be shifted only once here to
+                              // get the correct x-bpp offset.
+            "movq  %%mm3, %%mm1           \n\t" // now use mm1 for getting
+                                                // LBCarrys
+            "pand  %%mm2, %%mm1           \n\t" // get LBCarrys for each byte
+                                                // where both
+                              // lsb's were == 1 (only valid for active group)
+            "psrlq $1, %%mm2              \n\t" // divide raw bytes by 2
+            "pand  %%mm4, %%mm2           \n\t" // clear invalid bit 7 of each
+                                                // byte
+            "paddb %%mm1, %%mm2           \n\t" // add LBCarrys to Raw(x-bpp)/2
+                                                // for each byte
+            "pand  %%mm6, %%mm2           \n\t" // leave only Active Group 2
+                                                // bytes to add to Avg
+            "addl  $8, %%ecx              \n\t"
+            "paddb %%mm2, %%mm0           \n\t" // add (Raw/2) + LBCarrys to
+                                                // Avg for each Active byte
+            // now ready to write back to memory
+            "movq  %%mm0, -8(%1," PCX ",) \n\t"
+            // move updated Raw(x) to use as Raw(x-bpp) for next loop
+            "cmpl  %%eax, %%ecx           \n\t" // MMXLength
+            "movq  %%mm0, %%mm2           \n\t" // mov updated Raw(x) to mm2
+            "jb avg_3lp                   \n\t"
+
+            : "=S" (dummy_value_S),            // output regs (dummy)
+              "=D" (dummy_value_D),
+              "=c" (dummy_value_c),
+              "=a" (dummy_value_a)
+
+            : "0" (prev_row),    // esi/rsi    // input regs
+              "1" (row),         // edi/rdi
+              "2" (diff),        // ecx
+              "3" (MMXLength)    // eax
+
+#if defined(CLOBBER_MMX_REGS_SUPPORTED)
+            : "%mm0", "%mm1", "%mm2", "%mm3"   // clobber list
+            , "%mm4", "%mm5", "%mm6", "%mm7"
+#endif
+         );
+      }
+      break;  // end 3 bpp
+
+      case 4:   // formerly shared with 6 bpp case via _ShiftBpp and _ShiftRem,
+      {         // but loop uses all 8 MMX regs, and psrlq/psllq require 64-bit
+                // mem (PIC/.so problems), MMX reg (none left), or immediate
+//       _ShiftBpp = bpp << 3;        // 32 (psllq)
+//       _ShiftRem = 64 - _ShiftBpp;  // 32 (psrlq)
+
+         __asm__ __volatile__ (
+            LOAD_GOT_rbp
+            "movq " HB_CLEAR_MASK ", %%mm4 \n\t" // _HBClearMask -> mm4
+            "movq " LB_CARRY_MASK ", %%mm5 \n\t" // _LBCarryMask -> mm5
+            // re-init address pointers and offset
+// preload  "movl  diff, %%ecx             \n\t" // ecx:  x = offset to
+                                                 // alignment boundary
+            "movq " AMASK0_8_0 ", %%mm7    \n\t" // _amask0_8_0 -> mm7
+            RESTORE_rbp
+
+            // ... and clear all bytes except for 1st active group
+// preload  "movl  row, %1               \n\t" // edi:  Avg(x)
+            "psrlq $32, %%mm7            \n\t" // was _ShiftRem
+// preload  "movl  prev_row, %0          \n\t" // esi:  Prior(x)
+            "movq  %%mm7, %%mm6          \n\t"
+            "psllq $32, %%mm6            \n\t" // mask for 2nd active group
+
+            // prime the pump:  load the first Raw(x-bpp) data set
+            "movq -8(%1," PCX ",), %%mm2 \n\t" // load previous aligned 8 bytes
+                                             // (we correct pos. in loop below)
+         "avg_4lp:                       \n\t"
+            "movq (%1," PCX ",), %%mm0   \n\t"
+            "psrlq $32, %%mm2            \n\t" // shift data to pos. correctly
+            "movq (%0," PCX ",), %%mm1   \n\t"
+            // add (Prev_row/2) to average
+            "movq %%mm5, %%mm3           \n\t"
+            "pand %%mm1, %%mm3           \n\t" // get lsb for each prev_row byte
+            "psrlq $1, %%mm1             \n\t" // divide prev_row bytes by 2
+            "pand  %%mm4, %%mm1          \n\t" // clear invalid bit 7 of each
+                                               // byte
+            "paddb %%mm1, %%mm0          \n\t" // add (Prev_row/2) to Avg for
+                                               // each byte
+            // add 1st active group (Raw(x-bpp)/2) to average with _LBCarry
+            "movq %%mm3, %%mm1           \n\t" // now use mm1 for getting
+                                               // LBCarrys
+            "pand %%mm2, %%mm1           \n\t" // get LBCarrys for each byte
+                                               // where both
+                              // lsb's were == 1 (only valid for active group)
+            "psrlq $1, %%mm2             \n\t" // divide raw bytes by 2
+            "pand  %%mm4, %%mm2          \n\t" // clear invalid bit 7 of each
+                                               // byte
+            "paddb %%mm1, %%mm2          \n\t" // add LBCarrys to (Raw(x-bpp)/2)
+                                               // for each byte
+            "pand %%mm7, %%mm2           \n\t" // leave only Active Group 1
+                                               // bytes to add to Avg
+            "paddb %%mm2, %%mm0          \n\t" // add (Raw/2) + LBCarrys to Avg
+                                               // for each Active
+                              // byte
+            // add 2nd active group (Raw(x-bpp)/2) to average with _LBCarry
+            "movq %%mm0, %%mm2           \n\t" // mov updated Raws to mm2
+            "psllq $32, %%mm2            \n\t" // shift data to pos. correctly
+            "addl $8, %%ecx              \n\t"
+            "movq %%mm3, %%mm1           \n\t" // now use mm1 for getting
+                                               // LBCarrys
+            "pand %%mm2, %%mm1           \n\t" // get LBCarrys for each byte
+                                               // where both
+                              // lsb's were == 1 (only valid for active group)
+            "psrlq $1, %%mm2             \n\t" // divide raw bytes by 2
+            "pand  %%mm4, %%mm2          \n\t" // clear invalid bit 7 of each
+                                               // byte
+            "paddb %%mm1, %%mm2          \n\t" // add LBCarrys to (Raw(x-bpp)/2)
+                                               // for each byte
+            "pand %%mm6, %%mm2           \n\t" // leave only Active Group 2
+                                               // bytes to add to Avg
+            "paddb %%mm2, %%mm0          \n\t" // add (Raw/2) + LBCarrys to
+                                               // Avg for each Active byte
+            "cmpl %%eax, %%ecx           \n\t" // MMXLength
+            // now ready to write back to memory
+            "movq %%mm0, -8(%1," PCX ",) \n\t"
+            // prep Raw(x-bpp) for next loop
+            "movq %%mm0, %%mm2           \n\t" // mov updated Raws to mm2
+            "jb avg_4lp                  \n\t"
+
+            : "=S" (dummy_value_S),            // output regs (dummy)
+              "=D" (dummy_value_D),
+              "=c" (dummy_value_c),
+              "=a" (dummy_value_a)
+
+            : "0" (prev_row),    // esi/rsi    // input regs
+              "1" (row),         // edi/rdi
+              "2" (diff),        // ecx
+              "3" (MMXLength)    // eax
+
+#if defined(CLOBBER_MMX_REGS_SUPPORTED)
+            : "%mm0", "%mm1", "%mm2", "%mm3"   // clobber list
+            , "%mm4", "%mm5", "%mm6", "%mm7"
+#endif
+         );
+      }
+      break;  // end 4 bpp
+
+      case 1:
+      {
+         __asm__ __volatile__ (
+            // re-init address pointers and offset
+// preload  "movl diff, %%ecx            \n\t" // ecx: x = offset to align. bdry
+// preload  "movl row, %1                \n\t" // edi/rdi:  Avg(x)
+// preload  "movl FullLength, %%eax      \n\t"
+            "cmpl %%eax, %%ecx           \n\t" // test if offset at end of array
+            "jnb avg_1end                \n\t"
+
+            SAVE_ebp
+
+            // do Avg decode for remaining bytes
+// preload  "movl prev_row, %0           \n\t" // esi/rsi:  Prior(x)
+            "mov  %1, " PBP "            \n\t" // copy of row pointer...
+            "dec  " PBP "                \n\t" // ebp/rbp:  Raw(x-bpp)
+            "xorl %%edx, %%edx           \n\t" // zero edx before using dl & dx
+                                               //  in loop below
+            SAVE_GOT_ebx
+
+         "avg_1lp:                       \n\t"
+            // Raw(x) = Avg(x) + ((Raw(x-bpp) + Prior(x))/2)
+            "xorl %%ebx, %%ebx           \n\t"
+            "movb (%0," PCX ",), %%dl    \n\t" // load dl with Prior(x)
+            "movb (" PBP "," PCX ",), %%bl \n\t" // load bl with Raw(x-bpp)
+            "addw %%dx, %%bx             \n\t"
+            "incl %%ecx                  \n\t"
+            "shrw %%bx                   \n\t" // divide by 2
+            "addb -1(%1," PCX ",), %%bl  \n\t" // add Avg(x); -1 to offset
+                                               // inc ecx
+            "cmpl %%eax, %%ecx           \n\t" // check if at end of array
+            "movb %%bl, -1(%1," PCX ",)  \n\t" // write back Raw(x);
+                         // mov does not affect flags; -1 to offset inc ecx
+            "jb avg_1lp                  \n\t"
+
+            RESTORE_GOT_ebx
+            RESTORE_ebp
+
+         "avg_1end:                      \n\t"
+
+            : "=S" (dummy_value_S),            // output regs (dummy)
+              "=D" (dummy_value_D),
+              "=c" (dummy_value_c),
+              "=a" (dummy_value_a)
+
+            : "0" (prev_row),    // esi/rsi    // input regs
+              "1" (row),         // edi/rdi
+              "2" (diff),        // ecx
+              "3" (FullLength)   // eax
+
+            : "%edx"                           // clobber list
+              _CLOBBER_GOT_ebx
+              _CLOBBER_ebp
+         );
+      }
+      return;  // end 1 bpp
+
+      case 2:
+      {
+//       _ShiftBpp = 16;   // == 2 * 8
+//       _ShiftRem = 48;   // == 64 - _ShiftBpp
+
+         __asm__ __volatile__ (
+            LOAD_GOT_rbp
+            // load (former) _ActiveMask
+            "movq " AMASK6_2_0 ", %%mm7    \n\t" // _amask6_2_0 -> mm7
+            // re-init address pointers and offset
+// preload  "movl  diff, %%ecx             \n\t" // ecx:  x = offset to
+                                                 // alignment boundary
+            "movq " LB_CARRY_MASK ", %%mm5 \n\t" // _LBCarryMask -> mm5
+// preload  "movl  row, %1                 \n\t" // edi:  Avg(x)
+            "movq " HB_CLEAR_MASK ", %%mm4 \n\t" // _HBClearMask -> mm4
+// preload  "movl  prev_row, %0            \n\t" // esi:  Prior(x)
+            RESTORE_rbp
+
+            // prime the pump:  load the first Raw(x-bpp) data set
+            "movq -8(%1," PCX ",), %%mm2 \n\t" // load previous aligned 8 bytes
+                                             // (we correct pos. in loop below)
+         "avg_2lp:                       \n\t"
+            "movq (%1," PCX ",), %%mm0   \n\t"
+            "psrlq $48, %%mm2            \n\t" // shift data to pos. correctly
+            "movq (%0," PCX ",), %%mm1   \n\t" //  (GRR BUGFIX:  was psllq)
+            // add (Prev_row/2) to average
+            "movq %%mm5, %%mm3           \n\t"
+            "pand %%mm1, %%mm3           \n\t" // get lsb for each prev_row byte
+            "psrlq $1, %%mm1             \n\t" // divide prev_row bytes by 2
+            "pand  %%mm4, %%mm1          \n\t" // clear invalid bit 7 of each
+                                               // byte
+            "movq %%mm7, %%mm6           \n\t"
+            "paddb %%mm1, %%mm0          \n\t" // add (Prev_row/2) to Avg for
+                                               // each byte
+
+            // add 1st active group (Raw(x-bpp)/2) to average with _LBCarry
+            "movq %%mm3, %%mm1           \n\t" // now use mm1 for getting
+                                               // LBCarrys
+            "pand %%mm2, %%mm1           \n\t" // get LBCarrys for each byte
+                                               // where both
+                                               // lsb's were == 1 (only valid
+                                               // for active group)
+            "psrlq $1, %%mm2             \n\t" // divide raw bytes by 2
+            "pand  %%mm4, %%mm2          \n\t" // clear invalid bit 7 of each
+                                               // byte
+            "paddb %%mm1, %%mm2          \n\t" // add LBCarrys to (Raw(x-bpp)/2)
+                                               // for each byte
+            "pand %%mm6, %%mm2           \n\t" // leave only Active Group 1
+                                               // bytes to add to Avg
+            "paddb %%mm2, %%mm0          \n\t" // add (Raw/2) + LBCarrys to Avg
+                                               // for each Active byte
+
+            // add 2nd active group (Raw(x-bpp)/2) to average with _LBCarry
+            "psllq $16, %%mm6            \n\t" // shift the mm6 mask to cover
+                                               // bytes 2 & 3
+            "movq %%mm0, %%mm2           \n\t" // mov updated Raws to mm2
+            "psllq $16, %%mm2            \n\t" // shift data to pos. correctly
+            "movq %%mm3, %%mm1           \n\t" // now use mm1 for getting
+                                               // LBCarrys
+            "pand %%mm2, %%mm1           \n\t" // get LBCarrys for each byte
+                                               // where both
+                                               // lsb's were == 1 (only valid
+                                               // for active group)
+            "psrlq $1, %%mm2             \n\t" // divide raw bytes by 2
+            "pand  %%mm4, %%mm2          \n\t" // clear invalid bit 7 of each
+                                               // byte
+            "paddb %%mm1, %%mm2          \n\t" // add LBCarrys to (Raw(x-bpp)/2)
+                                               // for each byte
+            "pand %%mm6, %%mm2           \n\t" // leave only Active Group 2
+                                               // bytes to add to Avg
+            "paddb %%mm2, %%mm0          \n\t" // add (Raw/2) + LBCarrys to
+                                               // Avg for each Active byte
+
+            // add 3rd active group (Raw(x-bpp)/2) to average with _LBCarry
+            "psllq $16, %%mm6            \n\t" // shift the mm6 mask to cover
+                                               // bytes 4 & 5
+            "movq %%mm0, %%mm2           \n\t" // mov updated Raws to mm2
+            "psllq $16, %%mm2            \n\t" // shift data to pos. correctly
+            "movq %%mm3, %%mm1           \n\t" // now use mm1 for getting
+                                               // LBCarrys
+            "pand %%mm2, %%mm1           \n\t" // get LBCarrys for each byte
+                                               // where both lsb's were == 1
+                                               // (only valid for active group)
+            "psrlq $1, %%mm2             \n\t" // divide raw bytes by 2
+            "pand  %%mm4, %%mm2          \n\t" // clear invalid bit 7 of each
+                                               // byte
+            "paddb %%mm1, %%mm2          \n\t" // add LBCarrys to (Raw(x-bpp)/2)
+                                               // for each byte
+            "pand %%mm6, %%mm2           \n\t" // leave only Active Group 2
+                                               // bytes to add to Avg
+            "paddb %%mm2, %%mm0          \n\t" // add (Raw/2) + LBCarrys to
+                                               // Avg for each Active byte
+
+            // add 4th active group (Raw(x-bpp)/2) to average with _LBCarry
+            "psllq $16, %%mm6            \n\t" // shift the mm6 mask to cover
+                                               // bytes 6 & 7
+            "movq %%mm0, %%mm2           \n\t" // mov updated Raws to mm2
+            "psllq $16, %%mm2            \n\t" // shift data to pos. correctly
+            "addl $8, %%ecx              \n\t"
+            "movq %%mm3, %%mm1           \n\t" // now use mm1 for getting
+                                               // LBCarrys
+            "pand %%mm2, %%mm1           \n\t" // get LBCarrys for each byte
+                                               // where both
+                                               // lsb's were == 1 (only valid
+                                               // for active group)
+            "psrlq $1, %%mm2             \n\t" // divide raw bytes by 2
+            "pand  %%mm4, %%mm2          \n\t" // clear invalid bit 7 of each
+                                               // byte
+            "paddb %%mm1, %%mm2          \n\t" // add LBCarrys to (Raw(x-bpp)/2)
+                                               // for each byte
+            "pand %%mm6, %%mm2           \n\t" // leave only Active Group 2
+                                               // bytes to add to Avg
+            "paddb %%mm2, %%mm0          \n\t" // add (Raw/2) + LBCarrys to
+                                               // Avg for each Active byte
+            "cmpl %%eax, %%ecx           \n\t" // MMXLength
+            // now ready to write back to memory
+            "movq %%mm0, -8(%1," PCX ",) \n\t"
+            // prep Raw(x-bpp) for next loop
+            "movq %%mm0, %%mm2           \n\t" // mov updated Raws to mm2
+            "jb avg_2lp                  \n\t"
+
+            : "=S" (dummy_value_S),            // output regs (dummy)
+              "=D" (dummy_value_D),
+              "=c" (dummy_value_c),
+              "=a" (dummy_value_a)
+
+            : "0" (prev_row),    // esi/rsi    // input regs
+              "1" (row),         // edi/rdi
+              "2" (diff),        // ecx
+              "3" (MMXLength)    // eax
+
+#if defined(CLOBBER_MMX_REGS_SUPPORTED)
+            : "%mm0", "%mm1", "%mm2", "%mm3"   // clobber list
+            , "%mm4", "%mm5", "%mm6", "%mm7"
+#endif
+         );
+      }
+      break;  // end 2 bpp
+
+      case 6:   // formerly shared with 4 bpp case (see comments there)
+      {
+//       _ShiftBpp = bpp << 3;        // 48 (psllq)
+//       _ShiftRem = 64 - _ShiftBpp;  // 16 (psrlq)
+
+         __asm__ __volatile__ (
+            LOAD_GOT_rbp
+            "movq " HB_CLEAR_MASK ", %%mm4 \n\t" // _HBClearMask -> mm4
+            "movq " LB_CARRY_MASK ", %%mm5 \n\t" // _LBCarryMask -> mm5
+            // re-init address pointers and offset
+// preload  "movl  diff, %%ecx             \n\t" // ecx:  x = offset to
+                                                 // alignment boundary
+            "movq " AMASK0_8_0 ", %%mm7    \n\t" // _amask0_8_0 -> mm7
+            RESTORE_rbp
+
+            // ... and clear all bytes except for 1st active group
+// preload  "movl  row, %1               \n\t" // edi:  Avg(x)
+            "psrlq $16, %%mm7            \n\t"
+// preload  "movl  prev_row, %0          \n\t" // esi:  Prior(x)
+            "movq  %%mm7, %%mm6          \n\t"
+            "psllq $48, %%mm6            \n\t" // mask for 2nd active group
+
+            // prime the pump:  load the first Raw(x-bpp) data set
+            "movq -8(%1," PCX ",), %%mm2 \n\t" // load previous aligned 8 bytes
+                                             // (we correct pos. in loop below)
+         "avg_6lp:                       \n\t"
+            "movq (%1," PCX ",), %%mm0   \n\t"
+            "psrlq $16, %%mm2            \n\t" // shift data to pos. correctly
+            "movq (%0," PCX ",), %%mm1   \n\t"
+            // add (Prev_row/2) to average
+            "movq %%mm5, %%mm3           \n\t"
+            "pand %%mm1, %%mm3           \n\t" // get lsb for each prev_row byte
+            "psrlq $1, %%mm1             \n\t" // divide prev_row bytes by 2
+            "pand  %%mm4, %%mm1          \n\t" // clear invalid bit 7 of each
+                                               // byte
+            "paddb %%mm1, %%mm0          \n\t" // add (Prev_row/2) to Avg for
+                                               // each byte
+            // add 1st active group (Raw(x-bpp)/2) to average with _LBCarry
+            "movq %%mm3, %%mm1           \n\t" // now use mm1 for getting
+                                               // LBCarrys
+            "pand %%mm2, %%mm1           \n\t" // get LBCarrys for each byte
+                                               // where both
+                              // lsb's were == 1 (only valid for active group)
+            "psrlq $1, %%mm2             \n\t" // divide raw bytes by 2
+            "pand  %%mm4, %%mm2          \n\t" // clear invalid bit 7 of each
+                                               // byte
+            "paddb %%mm1, %%mm2          \n\t" // add LBCarrys to (Raw(x-bpp)/2)
+                                               // for each byte
+            "pand %%mm7, %%mm2           \n\t" // leave only Active Group 1
+                                               // bytes to add to Avg
+            "paddb %%mm2, %%mm0          \n\t" // add (Raw/2) + LBCarrys to Avg
+                                               // for each Active
+                              // byte
+            // add 2nd active group (Raw(x-bpp)/2) to average with _LBCarry
+            "movq %%mm0, %%mm2           \n\t" // mov updated Raws to mm2
+            "psllq $48, %%mm2            \n\t" // shift data to pos. correctly
+            "addl $8, %%ecx              \n\t"
+            "movq %%mm3, %%mm1           \n\t" // now use mm1 for getting
+                                               // LBCarrys
+            "pand %%mm2, %%mm1           \n\t" // get LBCarrys for each byte
+                                               // where both
+                              // lsb's were == 1 (only valid for active group)
+            "psrlq $1, %%mm2             \n\t" // divide raw bytes by 2
+            "pand  %%mm4, %%mm2          \n\t" // clear invalid bit 7 of each
+                                               // byte
+            "paddb %%mm1, %%mm2          \n\t" // add LBCarrys to (Raw(x-bpp)/2)
+                                               // for each byte
+            "pand %%mm6, %%mm2           \n\t" // leave only Active Group 2
+                                               // bytes to add to Avg
+            "paddb %%mm2, %%mm0          \n\t" // add (Raw/2) + LBCarrys to
+                                               // Avg for each Active byte
+            "cmpl %%eax, %%ecx           \n\t" // MMXLength
+            // now ready to write back to memory
+            "movq %%mm0, -8(%1," PCX ",) \n\t"
+            // prep Raw(x-bpp) for next loop
+            "movq %%mm0, %%mm2           \n\t" // mov updated Raws to mm2
+            "jb avg_6lp                  \n\t"
+
+            : "=S" (dummy_value_S),            // output regs (dummy)
+              "=D" (dummy_value_D),
+              "=c" (dummy_value_c),
+              "=a" (dummy_value_a)
+
+            : "0" (prev_row),    // esi/rsi    // input regs
+              "1" (row),         // edi/rdi
+              "2" (diff),        // ecx
+              "3" (MMXLength)    // eax
+
+#if defined(CLOBBER_MMX_REGS_SUPPORTED)
+            : "%mm0", "%mm1", "%mm2", "%mm3"   // clobber list
+            , "%mm4", "%mm5", "%mm6", "%mm7"
+#endif
+         );
+      }
+      break;  // end 6 bpp
+
+      case 8:
+      {
+         __asm__ __volatile__ (
+            // re-init address pointers and offset
+// preload  "movl  diff, %%ecx             \n\t" // ecx:  x = offset to
+                                                 // alignment boundary
+            LOAD_GOT_rbp
+            "movq " LB_CARRY_MASK ", %%mm5 \n\t" // [interleave for parallel.?]
+// preload  "movl  row, %1                 \n\t" // edi:  Avg(x)
+            "movq " HB_CLEAR_MASK ", %%mm4 \n\t" // _HBClearMask -> mm4
+// preload  "movl  prev_row, %0            \n\t" // esi:  Prior(x)
+            RESTORE_rbp
+
+            // prime the pump:  load the first Raw(x-bpp) data set
+            "movq -8(%1," PCX ",), %%mm2 \n\t" // load previous aligned 8 bytes
+                                      // (NO NEED to correct pos. in loop below)
+
+         "avg_8lp:                       \n\t"
+            "movq (%1," PCX ",), %%mm0   \n\t"
+            "movq %%mm5, %%mm3           \n\t"
+            "movq (%0," PCX ",), %%mm1   \n\t"
+            "addl $8, %%ecx              \n\t"
+            "pand %%mm1, %%mm3           \n\t" // get lsb for each prev_row byte
+            "psrlq $1, %%mm1             \n\t" // divide prev_row bytes by 2
+            "pand %%mm2, %%mm3           \n\t" // get LBCarrys for each byte
+                                               //  where both lsb's were == 1
+            "psrlq $1, %%mm2             \n\t" // divide raw bytes by 2
+            "pand  %%mm4, %%mm1          \n\t" // clear invalid bit 7, each byte
+            "paddb %%mm3, %%mm0          \n\t" // add LBCarrys to Avg, each byte
+            "pand  %%mm4, %%mm2          \n\t" // clear invalid bit 7, each byte
+            "paddb %%mm1, %%mm0          \n\t" // add (Prev_row/2) to Avg, each
+            "paddb %%mm2, %%mm0          \n\t" // add (Raw/2) to Avg for each
+            "cmpl %%eax, %%ecx           \n\t" // MMXLength
+            "movq %%mm0, -8(%1," PCX ",) \n\t"
+            "movq %%mm0, %%mm2           \n\t" // reuse as Raw(x-bpp)
+            "jb avg_8lp                  \n\t"
+
+            : "=S" (dummy_value_S),            // output regs (dummy)
+              "=D" (dummy_value_D),
+              "=c" (dummy_value_c),
+              "=a" (dummy_value_a)
+
+            : "0" (prev_row),    // esi/rsi    // input regs
+              "1" (row),         // edi/rdi
+              "2" (diff),        // ecx
+              "3" (MMXLength)    // eax
+
+#if defined(CLOBBER_MMX_REGS_SUPPORTED)
+            : "%mm0", "%mm1", "%mm2"           // clobber list
+            , "%mm3", "%mm4", "%mm5"
+#endif
+         );
+      }
+      break;  // end 8 bpp
+
+      default:                // bpp != 1,2,3,4,6,8:  doesn't exist
+      {
+         // ERROR:  SHOULD NEVER BE REACHED
+#if defined(PNG_DEBUG)
+         png_debug(1, "Internal libpng logic error (GCC "
+           "png_read_filter_row_mmx_avg())\n");
+#endif
+      }
+      break;
+
+   } // end switch (bpp)
+
+   __asm__ __volatile__ (
+      // MMX acceleration complete; now do clean-up
+      // check if any remaining bytes left to decode
+//pre "movl FullLength, %%edx      \n\t"
+//pre "movl MMXLength, %%eax       \n\t" // eax:  x == offset bytes after MMX
+//pre "movl row, %2                \n\t" // edi:  Avg(x)
+      "cmpl %%edx, %%eax           \n\t" // test if offset at end of array
+      "jnb avg_end                 \n\t"
+
+      SAVE_ebp
+
+      // do Avg decode for remaining bytes
+//pre "movl prev_row, %1           \n\t" // esi:  Prior(x)
+      "mov  %2, " PBP "            \n\t" // copy of row pointer...
+//pre "subl bpp, " PBP "           \n\t" // (bpp is preloaded into ecx)
+      "sub  " PCX "," PBP "        \n\t" // ebp:  Raw(x-bpp)
+      "xorl %%ecx, %%ecx           \n\t" // zero ecx before using cl & cx below
+
+      SAVE_GOT_ebx
+
+   "avg_lp2:                       \n\t"
+      // Raw(x) = Avg(x) + ((Raw(x-bpp) + Prior(x))/2)
+      "xorl %%ebx, %%ebx           \n\t"
+      "movb (%1," PAX ",), %%cl    \n\t" // load cl with Prior(x)
+      "movb (" PBP "," PAX ",), %%bl \n\t" // load bl with Raw(x-bpp)
+      "addw %%cx, %%bx             \n\t"
+      "incl %%eax                  \n\t"
+      "shrw %%bx                   \n\t" // divide by 2
+      "addb -1(%2," PAX ",), %%bl  \n\t" // add Avg(x); -1 to offset inc eax
+      "cmpl %%edx, %%eax           \n\t" // check if at end of array
+      "movb %%bl, -1(%2," PAX ",)  \n\t" // write back Raw(x) [mov does not
+      "jb avg_lp2                  \n\t" //  affect flags; -1 to offset inc eax]
+
+      RESTORE_GOT_ebx
+      RESTORE_ebp
+
+   "avg_end:                       \n\t"
+      "EMMS                        \n\t" // end MMX; prep for poss. FP instrs.
+
+      : "=c" (dummy_value_c),            // output regs (dummy)
+        "=S" (dummy_value_S),
+        "=D" (dummy_value_D),
+        "=a" (dummy_value_a),
+        "=d" (dummy_value_d)
+
+      : "0" (bpp),         // ecx        // input regs
+        "1" (prev_row),    // esi/rsi
+        "2" (row),         // edi/rdi
+        "3" (MMXLength),   // eax
+        "4" (FullLength)   // edx
+
+      CLOB_COLON_ebx_ebp                 // clobber list
+        CLOBBER_GOT_ebx
+        CLOB_COMMA_ebx_ebp
+        CLOBBER_ebp
+   );
+
+} /* end png_read_filter_row_mmx_avg() */
+
+#endif /* PNG_MMX_READ_FILTER_AVG_SUPPORTED */
+
+
+
+#if defined(PNG_MMX_READ_FILTER_PAETH_SUPPORTED)
+#if defined(PNG_x86_64_USE_GOTPCREL) || defined(PNG_THREAD_UNSAFE_OK)
+
+//===========================================================================//
+//                                                                           //
+//         P N G _ R E A D _ F I L T E R _ R O W _ M M X _ P A E T H         //
+//                                                                           //
+//===========================================================================//
+
+// Optimized code for PNG Paeth filter decoder
+
+static void /* PRIVATE */
+png_read_filter_row_mmx_paeth(png_row_infop row_info, png_bytep row,
+                              png_bytep prev_row)
+{
+   unsigned FullLength, MMXLength;  // png_uint_32 is actually 64-bit on x86-64
+   int bpp;
+   int dummy_value_a;
+   int dummy_value_c;   // fix 'forbidden register 2 (cx) was spilled' error
+   int dummy_value_d;
+   png_charp dummy_value_S;
+   png_charp dummy_value_D;
+   int diff; //     __attribute__((used));
+
+   bpp = (row_info->pixel_depth + 7) >> 3;  // calc number of bytes per pixel
+   FullLength = row_info->rowbytes;         // number of bytes to filter
+
+   __asm__ __volatile__ (
+      SAVE_GOT_ebx
+      SAVE_r15
+      SAVE_ebp
+//pre "movl row, %2                \n\t" // edi/rdi
+      "xorl %%ebx, %%ebx           \n\t" // ebx:  x offset
+//pre "movl prev_row, %1           \n\t" // esi/rsi
+      "xorl %%edx, %%edx           \n\t" // edx:  x-bpp offset
+//pre "movl FullLength, %%eax      \n\t" // bring in via eax...
+      SAVE_FullLength                    // ...but store for later use
+      "xorl %%eax, %%eax           \n\t"
+
+      // Compute the Raw value for the first bpp bytes
+      // Note: the formula works out to be always
+      //   Paeth(x) = Raw(x) + Prior(x)      where x < bpp
+   "paeth_rlp:                     \n\t"
+      "movb (%2," PBX ",), %%al    \n\t"
+      "addb (%1," PBX ",), %%al    \n\t"
+      "incl %%ebx                  \n\t"
+//pre "cmpl bpp, %%ebx             \n\t" (bpp is preloaded into ecx)
+      "cmpl %%ecx, %%ebx           \n\t"
+      "movb %%al, -1(%2," PBX ",)  \n\t"
+      "jb paeth_rlp                \n\t"
+
+      // get # of bytes to alignment (note:  computing _delta_ of two pointers,
+      // so hereafter %%ebp is sufficient even on 64-bit)
+      "mov  %2, " PBP "            \n\t" // take start of row
+      "add  " PBX "," PBP "        \n\t" // add bpp
+      "add  $0xf, " PBP "          \n\t" // add 7+8 to incr past alignment bdry
+//    "andl $0xfffffff8, %%ebp     \n\t" // mask to alignment boundary (32-bit!)
+      CLEAR_BOTTOM_3_BITS  PBP    "\n\t" // mask to alignment boundary
+      "sub  %2, " PBP "            \n\t" // subtract row ptr again => ebp =
+      "jz paeth_go                 \n\t" //  target value of ebx at alignment
+
+      "xorl %%ecx, %%ecx           \n\t"
+
+      SAVE_r11_r12_r13
+
+      // fix alignment
+   "paeth_lp1:                     \n\t"
+      "xorl %%eax, %%eax           \n\t"
+      // pav = p - a = (a + b - c) - a = b - c
+      "movb (%1," PBX ",), %%al    \n\t" // load Prior(x) into al
+      "movb (%1," PDX ",), %%cl    \n\t" // load Prior(x-bpp) into cl
+      "subl %%ecx, %%eax           \n\t" // subtract Prior(x-bpp)
+      "movl %%eax, " pa_TEMP "     \n\t" // Save pav for later use
+      "xorl %%eax, %%eax           \n\t"
+      // pbv = p - b = (a + b - c) - b = a - c
+      "movb (%2," PDX ",), %%al    \n\t" // load Raw(x-bpp) into al
+      "subl %%ecx, %%eax           \n\t" // subtract Prior(x-bpp)
+      "movl %%eax, %%ecx           \n\t"
+      // pcv = p - c = (a + b - c) - c = (a - c) + (b - c) = pav + pbv
+      "addl " pa_TEMP ", %%eax     \n\t" // pcv = pav + pbv
+      // pc = abs(pcv)
+      "testl $0x80000000, %%eax    \n\t"
+      "jz paeth_pca                \n\t"
+      "negl %%eax                  \n\t" // reverse sign of neg values
+
+   "paeth_pca:                     \n\t"
+      "movl %%eax, " pc_TEMP "     \n\t" // save pc for later use
+      // pb = abs(pbv)
+      "testl $0x80000000, %%ecx    \n\t"
+      "jz paeth_pba                \n\t"
+      "negl %%ecx                  \n\t" // reverse sign of neg values
+
+   "paeth_pba:                     \n\t"
+      "movl %%ecx, " pb_TEMP "     \n\t" // save pb for later use
+      // pa = abs(pav)
+      "movl " pa_TEMP ", %%eax     \n\t"
+      "testl $0x80000000, %%eax    \n\t"
+      "jz paeth_paa                \n\t"
+      "negl %%eax                  \n\t" // reverse sign of neg values
+
+   "paeth_paa:                     \n\t"
+      "movl %%eax, " pa_TEMP "     \n\t" // save pa for later use
+      // test if pa <= pb
+      "cmpl %%ecx, %%eax           \n\t"
+      "jna paeth_abb               \n\t"
+      // pa > pb; now test if pb <= pc
+      "cmpl " pc_TEMP ", %%ecx     \n\t"
+      "jna paeth_bbc               \n\t"
+      // pb > pc; Raw(x) = Paeth(x) + Prior(x-bpp)
+      "movb (%1," PDX ",), %%cl    \n\t" // load Prior(x-bpp) into cl
+      "jmp paeth_paeth             \n\t"
+
+   "paeth_bbc:                     \n\t"
+      // pb <= pc; Raw(x) = Paeth(x) + Prior(x)
+      "movb (%1," PBX ",), %%cl    \n\t" // load Prior(x) into cl
+      "jmp paeth_paeth             \n\t"
+
+   "paeth_abb:                     \n\t"
+      // pa <= pb; now test if pa <= pc
+      "cmpl " pc_TEMP ", %%eax     \n\t"
+      "jna paeth_abc               \n\t"
+      // pa > pc; Raw(x) = Paeth(x) + Prior(x-bpp)
+      "movb (%1," PDX ",), %%cl    \n\t" // load Prior(x-bpp) into cl
+      "jmp paeth_paeth             \n\t"
+
+   "paeth_abc:                     \n\t"
+      // pa <= pc; Raw(x) = Paeth(x) + Raw(x-bpp)
+      "movb (%2," PDX ",), %%cl    \n\t" // load Raw(x-bpp) into cl
+
+   "paeth_paeth:                   \n\t"
+      "incl %%ebx                  \n\t"
+      "incl %%edx                  \n\t"
+      // Raw(x) = (Paeth(x) + Paeth_Predictor( a, b, c )) mod 256
+      "addb %%cl, -1(%2," PBX ",)  \n\t"
+      "cmpl %%ebp, %%ebx           \n\t"
+      "jb paeth_lp1                \n\t"
+
+      RESTORE_r11_r12_r13
+
+   "paeth_go:                      \n\t"
+      RESTORE_FullLength "%%ecx    \n\t" // FullLength -> ecx
+      "movl %%ecx, %%eax           \n\t"
+      "subl %%ebx, %%eax           \n\t" // subtract alignment fix
+      "andl $0x00000007, %%eax     \n\t" // calc bytes over mult of 8
+      "subl %%eax, %%ecx           \n\t" // drop over bytes from original length
+//out "movl %%ecx, MMXLength       \n\t"
+      "movl %%ebp, %%eax           \n\t" // ebp = diff, but no reg constraint(?)
+      RESTORE_ebp                        //  (could swap ebp and edx functions)
+      RESTORE_r15
+      RESTORE_GOT_ebx
+
+      : "=c" (MMXLength),                // output regs
+        "=S" (dummy_value_S),
+        "=D" (dummy_value_D),
+        "=a" (diff)
+
+      : "0" (bpp),         // ecx        // input regs
+        "1" (prev_row),    // esi/rsi
+        "2" (row),         // edi/rdi
+        "3" (FullLength)   // eax
+
+      : "%edx"                           // clobber list
+        _CLOBBER_r11_r12_r13
+        _CLOBBER_r15
+        _CLOBBER_ebp
+        _CLOBBER_GOT_ebx
+   );
+
+   // now do the math for the rest of the row
+   switch (bpp)
+   {
+      case 3:
+      {
+//       _ShiftBpp = 24;    // == bpp * 8
+//       _ShiftRem = 40;    // == 64 - _ShiftBpp
+
+         __asm__ __volatile__ (
+            LOAD_GOT_rbp
+// preload  "movl diff, %%ecx            \n\t"
+// preload  "movl row, %1                \n\t" // edi/rdi
+// preload  "movl prev_row, %0           \n\t" // esi/rsi
+            "pxor %%mm0, %%mm0           \n\t"
+
+            // prime the pump:  load the first Raw(x-bpp) data set
+            "movq -8(%1," PCX ",), %%mm1 \n\t"
+         "paeth_3lp:                     \n\t"
+            "psrlq $40, %%mm1            \n\t" // shift last 3 bytes to 1st
+                                               // 3 bytes
+            "movq (%0," PCX ",), %%mm2   \n\t" // load b=Prior(x)
+            "punpcklbw %%mm0, %%mm1      \n\t" // unpack High bytes of a
+            "movq -8(%0," PCX ",), %%mm3 \n\t" // prep c=Prior(x-bpp) bytes
+            "punpcklbw %%mm0, %%mm2      \n\t" // unpack High bytes of b
+            "psrlq $40, %%mm3            \n\t" // shift last 3 bytes to 1st
+                                               // 3 bytes
+            // pav = p - a = (a + b - c) - a = b - c
+            "movq %%mm2, %%mm4           \n\t"
+            "punpcklbw %%mm0, %%mm3      \n\t" // unpack High bytes of c
+            // pbv = p - b = (a + b - c) - b = a - c
+            "movq %%mm1, %%mm5           \n\t"
+            "psubw %%mm3, %%mm4          \n\t"
+            "pxor %%mm7, %%mm7           \n\t"
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+            "movq %%mm4, %%mm6           \n\t"
+            "psubw %%mm3, %%mm5          \n\t"
+
+            // pa = abs(p-a) = abs(pav)
+            // pb = abs(p-b) = abs(pbv)
+            // pc = abs(p-c) = abs(pcv)
+            "pcmpgtw %%mm4, %%mm0        \n\t" // create mask pav bytes < 0
+            "paddw %%mm5, %%mm6          \n\t"
+            "pand %%mm4, %%mm0           \n\t" // only pav bytes < 0 in mm7
+            "pcmpgtw %%mm5, %%mm7        \n\t" // create mask pbv bytes < 0
+            "psubw %%mm0, %%mm4          \n\t"
+            "pand %%mm5, %%mm7           \n\t" // only pbv bytes < 0 in mm0
+            "psubw %%mm0, %%mm4          \n\t"
+            "psubw %%mm7, %%mm5          \n\t"
+            "pxor %%mm0, %%mm0           \n\t"
+            "pcmpgtw %%mm6, %%mm0        \n\t" // create mask pcv bytes < 0
+            "pand %%mm6, %%mm0           \n\t" // only pav bytes < 0 in mm7
+            "psubw %%mm7, %%mm5          \n\t"
+            "psubw %%mm0, %%mm6          \n\t"
+            //  test pa <= pb
+            "movq %%mm4, %%mm7           \n\t"
+            "psubw %%mm0, %%mm6          \n\t"
+            "pcmpgtw %%mm5, %%mm7        \n\t" // pa > pb?
+            "movq %%mm7, %%mm0           \n\t"
+            // use mm7 mask to merge pa & pb
+            "pand %%mm7, %%mm5           \n\t"
+            // use mm0 mask copy to merge a & b
+            "pand %%mm0, %%mm2           \n\t"
+            "pandn %%mm4, %%mm7          \n\t"
+            "pandn %%mm1, %%mm0          \n\t"
+            "paddw %%mm5, %%mm7          \n\t"
+            "paddw %%mm2, %%mm0          \n\t"
+            //  test  ((pa <= pb)? pa:pb) <= pc
+            "pcmpgtw %%mm6, %%mm7        \n\t" // pab > pc?
+            "pxor %%mm1, %%mm1           \n\t"
+            "pand %%mm7, %%mm3           \n\t"
+            "pandn %%mm0, %%mm7          \n\t"
+            "paddw %%mm3, %%mm7          \n\t"
+            "pxor %%mm0, %%mm0           \n\t"
+            "packuswb %%mm1, %%mm7       \n\t"
+            "movq (%0," PCX ",), %%mm3   \n\t" // load c=Prior(x-bpp)
+            "pand " AMASK5_3_0 ", %%mm7  \n\t" // _amask5_3_0 (was _ActiveMask)
+            "movq %%mm3, %%mm2           \n\t" // load b=Prior(x) step 1
+            "paddb (%1," PCX ",), %%mm7  \n\t" // add Paeth predictor + Raw(x)
+            "punpcklbw %%mm0, %%mm3      \n\t" // unpack High bytes of c
+            "movq %%mm7, (%1," PCX ",)   \n\t" // write back updated value
+            "movq %%mm7, %%mm1           \n\t" // now mm1 will be used as
+                                               // Raw(x-bpp)
+            // now do Paeth for 2nd set of bytes (3-5)
+            "psrlq $24, %%mm2            \n\t" // load b=Prior(x) step 2
+            "punpcklbw %%mm0, %%mm1      \n\t" // unpack High bytes of a
+            "pxor %%mm7, %%mm7           \n\t"
+            "punpcklbw %%mm0, %%mm2      \n\t" // unpack High bytes of b
+            // pbv = p - b = (a + b - c) - b = a - c
+            "movq %%mm1, %%mm5           \n\t"
+            // pav = p - a = (a + b - c) - a = b - c
+            "movq %%mm2, %%mm4           \n\t"
+            "psubw %%mm3, %%mm5          \n\t"
+            "psubw %%mm3, %%mm4          \n\t"
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) =
+            //       pav + pbv = pbv + pav
+            "movq %%mm5, %%mm6           \n\t"
+            "paddw %%mm4, %%mm6          \n\t"
+
+            // pa = abs(p-a) = abs(pav)
+            // pb = abs(p-b) = abs(pbv)
+            // pc = abs(p-c) = abs(pcv)
+            "pcmpgtw %%mm5, %%mm0        \n\t" // create mask pbv bytes < 0
+            "pcmpgtw %%mm4, %%mm7        \n\t" // create mask pav bytes < 0
+            "pand %%mm5, %%mm0           \n\t" // only pbv bytes < 0 in mm0
+            "pand %%mm4, %%mm7           \n\t" // only pav bytes < 0 in mm7
+            "psubw %%mm0, %%mm5          \n\t"
+            "psubw %%mm7, %%mm4          \n\t"
+            "psubw %%mm0, %%mm5          \n\t"
+            "psubw %%mm7, %%mm4          \n\t"
+            "pxor %%mm0, %%mm0           \n\t"
+            "pcmpgtw %%mm6, %%mm0        \n\t" // create mask pcv bytes < 0
+            "pand %%mm6, %%mm0           \n\t" // only pav bytes < 0 in mm7
+            "psubw %%mm0, %%mm6          \n\t"
+            //  test pa <= pb
+            "movq %%mm4, %%mm7           \n\t"
+            "psubw %%mm0, %%mm6          \n\t"
+            "pcmpgtw %%mm5, %%mm7        \n\t" // pa > pb?
+            "movq %%mm7, %%mm0           \n\t"
+            // use mm7 mask to merge pa & pb
+            "pand %%mm7, %%mm5           \n\t"
+            // use mm0 mask copy to merge a & b
+            "pand %%mm0, %%mm2           \n\t"
+            "pandn %%mm4, %%mm7          \n\t"
+            "pandn %%mm1, %%mm0          \n\t"
+            "paddw %%mm5, %%mm7          \n\t"
+            "paddw %%mm2, %%mm0          \n\t"
+            //  test  ((pa <= pb)? pa:pb) <= pc
+            "pcmpgtw %%mm6, %%mm7        \n\t" // pab > pc?
+            "movq (%0," PCX ",), %%mm2   \n\t" // load b=Prior(x)
+            "pand %%mm7, %%mm3           \n\t"
+            "pandn %%mm0, %%mm7          \n\t"
+            "pxor %%mm1, %%mm1           \n\t"
+            "paddw %%mm3, %%mm7          \n\t"
+            "pxor %%mm0, %%mm0           \n\t"
+            "packuswb %%mm1, %%mm7       \n\t"
+            "movq %%mm2, %%mm3           \n\t" // load c=Prior(x-bpp) step 1
+            "pand " AMASK5_3_0 ", %%mm7  \n\t" // _amask5_3_0 (was _ActiveMask)
+            "punpckhbw %%mm0, %%mm2      \n\t" // unpack High bytes of b
+            "psllq $24, %%mm7            \n\t" // shift bytes to 2nd group of
+                                               // 3 bytes
+             // pav = p - a = (a + b - c) - a = b - c
+            "movq %%mm2, %%mm4           \n\t"
+            "paddb (%1," PCX ",), %%mm7  \n\t" // add Paeth predictor + Raw(x)
+            "psllq $24, %%mm3            \n\t" // load c=Prior(x-bpp) step 2
+            "movq %%mm7, (%1," PCX ",)   \n\t" // write back updated value
+            "movq %%mm7, %%mm1           \n\t"
+            "punpckhbw %%mm0, %%mm3      \n\t" // unpack High bytes of c
+            "psllq $24, %%mm1            \n\t" // shift bytes (was _ShiftBpp)
+                                    // now mm1 will be used as Raw(x-bpp)
+            // now do Paeth for 3rd, and final, set of bytes (6-7)
+            "pxor %%mm7, %%mm7           \n\t"
+            "punpckhbw %%mm0, %%mm1      \n\t" // unpack High bytes of a
+            "psubw %%mm3, %%mm4          \n\t"
+            // pbv = p - b = (a + b - c) - b = a - c
+            "movq %%mm1, %%mm5           \n\t"
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+            "movq %%mm4, %%mm6           \n\t"
+            "psubw %%mm3, %%mm5          \n\t"
+            "pxor %%mm0, %%mm0           \n\t"
+            "paddw %%mm5, %%mm6          \n\t"
+
+            // pa = abs(p-a) = abs(pav)
+            // pb = abs(p-b) = abs(pbv)
+            // pc = abs(p-c) = abs(pcv)
+            "pcmpgtw %%mm4, %%mm0        \n\t" // create mask pav bytes < 0
+            "pcmpgtw %%mm5, %%mm7        \n\t" // create mask pbv bytes < 0
+            "pand %%mm4, %%mm0           \n\t" // only pav bytes < 0 in mm7
+            "pand %%mm5, %%mm7           \n\t" // only pbv bytes < 0 in mm0
+            "psubw %%mm0, %%mm4          \n\t"
+            "psubw %%mm7, %%mm5          \n\t"
+            "psubw %%mm0, %%mm4          \n\t"
+            "psubw %%mm7, %%mm5          \n\t"
+            "pxor %%mm0, %%mm0           \n\t"
+            "pcmpgtw %%mm6, %%mm0        \n\t" // create mask pcv bytes < 0
+            "pand %%mm6, %%mm0           \n\t" // only pav bytes < 0 in mm7
+            "psubw %%mm0, %%mm6          \n\t"
+            //  test pa <= pb
+            "movq %%mm4, %%mm7           \n\t"
+            "psubw %%mm0, %%mm6          \n\t"
+            "pcmpgtw %%mm5, %%mm7        \n\t" // pa > pb?
+            "movq %%mm7, %%mm0           \n\t"
+            // use mm0 mask copy to merge a & b
+            "pand %%mm0, %%mm2           \n\t"
+            // use mm7 mask to merge pa & pb
+            "pand %%mm7, %%mm5           \n\t"
+            "pandn %%mm1, %%mm0          \n\t"
+            "pandn %%mm4, %%mm7          \n\t"
+            "paddw %%mm2, %%mm0          \n\t"
+            "paddw %%mm5, %%mm7          \n\t"
+            //  test  ((pa <= pb)? pa:pb) <= pc
+            "pcmpgtw %%mm6, %%mm7        \n\t" // pab > pc?
+            "pand %%mm7, %%mm3           \n\t"
+            "pandn %%mm0, %%mm7          \n\t"
+            "paddw %%mm3, %%mm7          \n\t"
+            "pxor %%mm1, %%mm1           \n\t"
+            "packuswb %%mm7, %%mm1       \n\t"
+            // step ecx to next set of 8 bytes and repeat loop til done
+            "addl $8, %%ecx              \n\t"
+            "pand " AMASK0_2_6 ", %%mm1  \n\t" // _amask0_2_6 (_ActiveMaskEnd)
+            "paddb -8(%1," PCX ",), %%mm1 \n\t" // add Paeth predictor + Raw(x)
+            "cmpl %%eax, %%ecx           \n\t" // MMXLength
+            "pxor %%mm0, %%mm0           \n\t" // pxor does not affect flags
+            "movq %%mm1, -8(%1," PCX ",) \n\t" // write back updated value
+                                 // mm1 will be used as Raw(x-bpp) next loop
+                           // mm3 ready to be used as Prior(x-bpp) next loop
+            "jb paeth_3lp                \n\t"
+            RESTORE_rbp
+
+            : "=S" (dummy_value_S),            // output regs (dummy)
+              "=D" (dummy_value_D),
+              "=c" (dummy_value_c),
+              "=a" (dummy_value_a)
+
+            : "0" (prev_row),  // esi/rsi      // input regs
+              "1" (row),       // edi/rdi
+              "2" (diff),      // ecx
+              "3" (MMXLength)  // eax
+
+#if defined(CLOBBER_MMX_REGS_SUPPORTED)
+            : "%mm0", "%mm1", "%mm2", "%mm3"   // clobber list
+            , "%mm4", "%mm5", "%mm6", "%mm7"
+#endif
+         );
+      }
+      break;  // end 3 bpp
+
+      case 4:
+      {
+         __asm__ __volatile__ (
+// preload  "movl diff, %%ecx            \n\t"
+// preload  "movl row, %1                \n\t" // edi/rdi
+// preload  "movl prev_row, %0           \n\t" // esi/rsi
+            "pxor %%mm0, %%mm0           \n\t"
+            // prime the pump:  load the first Raw(x-bpp) data set
+            "movq -8(%1," PCX ",), %%mm1 \n\t" // only time should need to read
+                                               //  a=Raw(x-bpp) bytes
+         "paeth_4lp:                     \n\t"
+            // do first set of 4 bytes
+            "movq -8(%0," PCX ",), %%mm3 \n\t" // read c=Prior(x-bpp) bytes
+            "punpckhbw %%mm0, %%mm1      \n\t" // unpack Low bytes of a
+            "movq (%0," PCX ",), %%mm2   \n\t" // load b=Prior(x)
+            "punpcklbw %%mm0, %%mm2      \n\t" // unpack High bytes of b
+            // pav = p - a = (a + b - c) - a = b - c
+            "movq %%mm2, %%mm4           \n\t"
+            "punpckhbw %%mm0, %%mm3      \n\t" // unpack High bytes of c
+            // pbv = p - b = (a + b - c) - b = a - c
+            "movq %%mm1, %%mm5           \n\t"
+            "psubw %%mm3, %%mm4          \n\t"
+            "pxor %%mm7, %%mm7           \n\t"
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+            "movq %%mm4, %%mm6           \n\t"
+            "psubw %%mm3, %%mm5          \n\t"
+            // pa = abs(p-a) = abs(pav)
+            // pb = abs(p-b) = abs(pbv)
+            // pc = abs(p-c) = abs(pcv)
+            "pcmpgtw %%mm4, %%mm0        \n\t" // create mask pav bytes < 0
+            "paddw %%mm5, %%mm6          \n\t"
+            "pand %%mm4, %%mm0           \n\t" // only pav bytes < 0 in mm7
+            "pcmpgtw %%mm5, %%mm7        \n\t" // create mask pbv bytes < 0
+            "psubw %%mm0, %%mm4          \n\t"
+            "pand %%mm5, %%mm7           \n\t" // only pbv bytes < 0 in mm0
+            "psubw %%mm0, %%mm4          \n\t"
+            "psubw %%mm7, %%mm5          \n\t"
+            "pxor %%mm0, %%mm0           \n\t"
+            "pcmpgtw %%mm6, %%mm0        \n\t" // create mask pcv bytes < 0
+            "pand %%mm6, %%mm0           \n\t" // only pav bytes < 0 in mm7
+            "psubw %%mm7, %%mm5          \n\t"
+            "psubw %%mm0, %%mm6          \n\t"
+            //  test pa <= pb
+            "movq %%mm4, %%mm7           \n\t"
+            "psubw %%mm0, %%mm6          \n\t"
+            "pcmpgtw %%mm5, %%mm7        \n\t" // pa > pb?
+            "movq %%mm7, %%mm0           \n\t"
+            // use mm7 mask to merge pa & pb
+            "pand %%mm7, %%mm5           \n\t"
+            // use mm0 mask copy to merge a & b
+            "pand %%mm0, %%mm2           \n\t"
+            "pandn %%mm4, %%mm7          \n\t"
+            "pandn %%mm1, %%mm0          \n\t"
+            "paddw %%mm5, %%mm7          \n\t"
+            "paddw %%mm2, %%mm0          \n\t"
+            //  test  ((pa <= pb)? pa:pb) <= pc
+            "pcmpgtw %%mm6, %%mm7        \n\t" // pab > pc?
+            "pxor %%mm1, %%mm1           \n\t"
+            "pand %%mm7, %%mm3           \n\t"
+            "pandn %%mm0, %%mm7          \n\t"
+            "paddw %%mm3, %%mm7          \n\t"
+            "pxor %%mm0, %%mm0           \n\t"
+            "packuswb %%mm1, %%mm7       \n\t"
+            "movq (%0," PCX ",), %%mm3   \n\t" // load c=Prior(x-bpp)
+            LOAD_GOT_rbp
+            "pand " AMASK4_4_0 ", %%mm7  \n\t" // _amask4_4_0 (was _ActiveMask)
+            RESTORE_rbp
+            "movq %%mm3, %%mm2           \n\t" // load b=Prior(x) step 1
+            "paddb (%1," PCX ",), %%mm7  \n\t" // add Paeth predictor + Raw(x)
+            "punpcklbw %%mm0, %%mm3      \n\t" // unpack High bytes of c
+            "movq %%mm7, (%1," PCX ",)   \n\t" // write back updated value
+            "movq %%mm7, %%mm1           \n\t" // now mm1 will be used as
+                                               // Raw(x-bpp)
+            // do second set of 4 bytes
+            "punpckhbw %%mm0, %%mm2      \n\t" // unpack Low bytes of b
+            "punpcklbw %%mm0, %%mm1      \n\t" // unpack Low bytes of a
+            // pav = p - a = (a + b - c) - a = b - c
+            "movq %%mm2, %%mm4           \n\t"
+            // pbv = p - b = (a + b - c) - b = a - c
+            "movq %%mm1, %%mm5           \n\t"
+            "psubw %%mm3, %%mm4          \n\t"
+            "pxor %%mm7, %%mm7           \n\t"
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+            "movq %%mm4, %%mm6           \n\t"
+            "psubw %%mm3, %%mm5          \n\t"
+            // pa = abs(p-a) = abs(pav)
+            // pb = abs(p-b) = abs(pbv)
+            // pc = abs(p-c) = abs(pcv)
+            "pcmpgtw %%mm4, %%mm0        \n\t" // create mask pav bytes < 0
+            "paddw %%mm5, %%mm6          \n\t"
+            "pand %%mm4, %%mm0           \n\t" // only pav bytes < 0 in mm7
+            "pcmpgtw %%mm5, %%mm7        \n\t" // create mask pbv bytes < 0
+            "psubw %%mm0, %%mm4          \n\t"
+            "pand %%mm5, %%mm7           \n\t" // only pbv bytes < 0 in mm0
+            "psubw %%mm0, %%mm4          \n\t"
+            "psubw %%mm7, %%mm5          \n\t"
+            "pxor %%mm0, %%mm0           \n\t"
+            "pcmpgtw %%mm6, %%mm0        \n\t" // create mask pcv bytes < 0
+            "pand %%mm6, %%mm0           \n\t" // only pav bytes < 0 in mm7
+            "psubw %%mm7, %%mm5          \n\t"
+            "psubw %%mm0, %%mm6          \n\t"
+            //  test pa <= pb
+            "movq %%mm4, %%mm7           \n\t"
+            "psubw %%mm0, %%mm6          \n\t"
+            "pcmpgtw %%mm5, %%mm7        \n\t" // pa > pb?
+            "movq %%mm7, %%mm0           \n\t"
+            // use mm7 mask to merge pa & pb
+            "pand %%mm7, %%mm5           \n\t"
+            // use mm0 mask copy to merge a & b
+            "pand %%mm0, %%mm2           \n\t"
+            "pandn %%mm4, %%mm7          \n\t"
+            "pandn %%mm1, %%mm0          \n\t"
+            "paddw %%mm5, %%mm7          \n\t"
+            "paddw %%mm2, %%mm0          \n\t"
+            //  test  ((pa <= pb)? pa:pb) <= pc
+            "pcmpgtw %%mm6, %%mm7        \n\t" // pab > pc?
+            "pxor %%mm1, %%mm1           \n\t"
+            "pand %%mm7, %%mm3           \n\t"
+            "pandn %%mm0, %%mm7          \n\t"
+            "pxor %%mm1, %%mm1           \n\t"
+            "paddw %%mm3, %%mm7          \n\t"
+            "pxor %%mm0, %%mm0           \n\t"
+            // step ecx to next set of 8 bytes and repeat loop til done
+            "addl $8, %%ecx              \n\t"
+            "packuswb %%mm7, %%mm1       \n\t"
+            "paddb -8(%1," PCX ",), %%mm1 \n\t" // add predictor with Raw(x)
+            "cmpl %%eax, %%ecx           \n\t" // MMXLength
+            "movq %%mm1, -8(%1," PCX ",) \n\t" // write back updated value
+                                 // mm1 will be used as Raw(x-bpp) next loop
+            "jb paeth_4lp                \n\t"
+
+            : "=S" (dummy_value_S),            // output regs (dummy)
+              "=D" (dummy_value_D),
+              "=c" (dummy_value_c),
+              "=a" (dummy_value_a)
+
+            : "0" (prev_row),  // esi/rsi      // input regs
+              "1" (row),       // edi/rdi
+              "2" (diff),      // ecx
+              "3" (MMXLength)  // eax
+
+#if defined(CLOBBER_MMX_REGS_SUPPORTED)
+            : "%mm0", "%mm1", "%mm2", "%mm3"   // clobber list
+            , "%mm4", "%mm5", "%mm6", "%mm7"
+#endif
+         );
+      }
+      break;  // end 4 bpp
+
+      case 1:
+      case 2:
+      {
+         __asm__ __volatile__ (
+// preload  "movl diff, %%eax            \n\t" // eax: x = offset to align. bdry
+// preload  "movl FullLength, %%edx      \n\t"
+            "cmpl %%edx, %%eax           \n\t"
+            "jnb paeth_dend              \n\t"
+
+            SAVE_ebp
+
+// preload  "movl row, %2                \n\t" // edi/rdi
+            // do Paeth decode for remaining bytes
+// preload  "movl prev_row, %1           \n\t" // esi/rsi
+            "movl %%eax, %%ebp           \n\t"
+// preload  "subl bpp, %%ebp             \n\t" // (bpp is preloaded into ecx)
+            "subl %%ecx, %%ebp           \n\t" // ebp = eax - bpp
+            "xorl %%ecx, %%ecx           \n\t" // zero ecx before using cl & cx
+
+            SAVE_GOT_ebx
+            SAVE_r11_r12_r13
+
+         "paeth_dlp:                     \n\t"
+            "xorl %%ebx, %%ebx           \n\t"
+            // pav = p - a = (a + b - c) - a = b - c
+            "movb (%1," PAX ",), %%bl    \n\t" // load Prior(x) into bl
+            "movb (%1," PBP ",), %%cl    \n\t" // load Prior(x-bpp) into cl
+            "subl %%ecx, %%ebx           \n\t" // subtract Prior(x-bpp)
+            "movl %%ebx, " pa_TEMP "     \n\t" // Save pav for later use
+            "xorl %%ebx, %%ebx           \n\t"
+            // pbv = p - b = (a + b - c) - b = a - c
+            "movb (%2," PBP ",), %%bl    \n\t" // load Raw(x-bpp) into bl
+            "subl %%ecx, %%ebx           \n\t" // subtract Prior(x-bpp)
+            "movl %%ebx, %%ecx           \n\t"
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+            "addl " pa_TEMP ", %%ebx     \n\t" // pcv = pav + pbv
+            // pc = abs(pcv)
+            "testl $0x80000000, %%ebx    \n\t"
+            "jz paeth_dpca               \n\t"
+            "negl %%ebx                  \n\t" // reverse sign of neg values
+
+         "paeth_dpca:                    \n\t"
+            "movl %%ebx, " pc_TEMP "     \n\t" // save pc for later use
+            // pb = abs(pbv)
+            "testl $0x80000000, %%ecx    \n\t"
+            "jz paeth_dpba               \n\t"
+            "negl %%ecx                  \n\t" // reverse sign of neg values
+
+         "paeth_dpba:                    \n\t"
+            "movl %%ecx, " pb_TEMP "     \n\t" // save pb for later use
+            // pa = abs(pav)
+            "movl " pa_TEMP ", %%ebx     \n\t"
+            "testl $0x80000000, %%ebx    \n\t"
+            "jz paeth_dpaa               \n\t"
+            "negl %%ebx                  \n\t" // reverse sign of neg values
+
+         "paeth_dpaa:                    \n\t"
+            "movl %%ebx, " pa_TEMP "     \n\t" // save pa for later use
+            // test if pa <= pb
+            "cmpl %%ecx, %%ebx           \n\t"
+            "jna paeth_dabb              \n\t"
+            // pa > pb; now test if pb <= pc
+            "cmpl " pc_TEMP ", %%ecx     \n\t"
+            "jna paeth_dbbc              \n\t"
+            // pb > pc; Raw(x) = Paeth(x) + Prior(x-bpp)
+            "movb (%1," PBP ",), %%cl    \n\t" // load Prior(x-bpp) into cl
+            "jmp paeth_dpaeth            \n\t"
+
+         "paeth_dbbc:                    \n\t"
+            // pb <= pc; Raw(x) = Paeth(x) + Prior(x)
+            "movb (%1," PAX ",), %%cl    \n\t" // load Prior(x) into cl
+            "jmp paeth_dpaeth            \n\t"
+
+         "paeth_dabb:                    \n\t"
+            // pa <= pb; now test if pa <= pc
+            "cmpl " pc_TEMP ", %%ebx     \n\t"
+            "jna paeth_dabc              \n\t"
+            // pa > pc; Raw(x) = Paeth(x) + Prior(x-bpp)
+            "movb (%1," PBP ",), %%cl   \n\t" // load Prior(x-bpp) into cl
+            "jmp paeth_dpaeth            \n\t"
+
+         "paeth_dabc:                    \n\t"
+            // pa <= pc; Raw(x) = Paeth(x) + Raw(x-bpp)
+            "movb (%2," PBP ",), %%cl    \n\t" // load Raw(x-bpp) into cl
+
+         "paeth_dpaeth:                  \n\t"
+            "incl %%eax                  \n\t"
+            "incl %%ebp                  \n\t"
+            // Raw(x) = (Paeth(x) + Paeth_Predictor( a, b, c )) mod 256
+            "addb %%cl, -1(%2," PAX ",)  \n\t"
+            "cmpl %%edx, %%eax           \n\t" // check against FullLength
+            "jb paeth_dlp                \n\t"
+
+            RESTORE_r11_r12_r13
+            RESTORE_GOT_ebx
+            RESTORE_ebp
+
+         "paeth_dend:                    \n\t"
+
+            : "=c" (dummy_value_c),            // output regs (dummy)
+              "=S" (dummy_value_S),
+              "=D" (dummy_value_D),
+              "=a" (dummy_value_a),
+              "=d" (dummy_value_d)
+
+            : "0" (bpp),         // ecx        // input regs
+              "1" (prev_row),    // esi/rsi
+              "2" (row),         // edi/rdi
+              "3" (diff),        // eax
+              "4" (FullLength)   // edx
+
+            CLOB_COLON_ebx_ebp_r1X             // clobber list
+              CLOBBER_GOT_ebx
+              CLOB_COMMA_ebx_ebp
+              CLOBBER_ebp
+              CLOB_COMMA_ebX_r1X
+              CLOBBER_r11_r12_r13
+         );
+      }
+      return; // end 1 or 2 bpp (no need to go further with this one)
+
+      case 6:
+      {
+//       _ActiveMask2 = 0xffffffff00000000LL;  // NOT USED ("_amask_0_4_4")
+//       _ShiftBpp = 48;       // bpp << 3 == bpp * 8
+//       _ShiftRem = 16;       // 64 - _ShiftBpp
+
+         __asm__ __volatile__ (
+// preload  "movl diff, %%ecx            \n\t"
+// preload  "movl row, %1                \n\t" // edi/rdi
+// preload  "movl prev_row, %0           \n\t" // esi/rsi
+            // prime the pump:  load the first Raw(x-bpp) data set
+            "movq -8(%1," PCX ",), %%mm1 \n\t"
+            "pxor %%mm0, %%mm0           \n\t"
+
+         "paeth_6lp:                     \n\t"
+            // must shift to position Raw(x-bpp) data
+            "psrlq $16, %%mm1            \n\t" // was _ShiftRem
+            // do first set of 4 bytes
+            "movq -8(%0," PCX ",), %%mm3 \n\t" // read c=Prior(x-bpp) bytes
+            "punpcklbw %%mm0, %%mm1      \n\t" // unpack Low bytes of a
+            "movq (%0," PCX ",), %%mm2   \n\t" // load b=Prior(x)
+            "punpcklbw %%mm0, %%mm2      \n\t" // unpack Low bytes of b
+            // must shift to position Prior(x-bpp) data
+            "psrlq $16, %%mm3            \n\t" // was _ShiftRem
+            // pav = p - a = (a + b - c) - a = b - c
+            "movq %%mm2, %%mm4           \n\t"
+            "punpcklbw %%mm0, %%mm3      \n\t" // unpack Low bytes of c
+            // pbv = p - b = (a + b - c) - b = a - c
+            "movq %%mm1, %%mm5           \n\t"
+            "psubw %%mm3, %%mm4          \n\t"
+            "pxor %%mm7, %%mm7           \n\t"
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+            "movq %%mm4, %%mm6           \n\t"
+            "psubw %%mm3, %%mm5          \n\t"
+            // pa = abs(p-a) = abs(pav)
+            // pb = abs(p-b) = abs(pbv)
+            // pc = abs(p-c) = abs(pcv)
+            "pcmpgtw %%mm4, %%mm0        \n\t" // create mask pav bytes < 0
+            "paddw %%mm5, %%mm6          \n\t"
+            "pand %%mm4, %%mm0           \n\t" // only pav bytes < 0 in mm7
+            "pcmpgtw %%mm5, %%mm7        \n\t" // create mask pbv bytes < 0
+            "psubw %%mm0, %%mm4          \n\t"
+            "pand %%mm5, %%mm7           \n\t" // only pbv bytes < 0 in mm0
+            "psubw %%mm0, %%mm4          \n\t"
+            "psubw %%mm7, %%mm5          \n\t"
+            "pxor %%mm0, %%mm0           \n\t"
+            "pcmpgtw %%mm6, %%mm0        \n\t" // create mask pcv bytes < 0
+            "pand %%mm6, %%mm0           \n\t" // only pav bytes < 0 in mm7
+            "psubw %%mm7, %%mm5          \n\t"
+            "psubw %%mm0, %%mm6          \n\t"
+            //  test pa <= pb
+            "movq %%mm4, %%mm7           \n\t"
+            "psubw %%mm0, %%mm6          \n\t"
+            "pcmpgtw %%mm5, %%mm7        \n\t" // pa > pb?
+            "movq %%mm7, %%mm0           \n\t"
+            // use mm7 mask to merge pa & pb
+            "pand %%mm7, %%mm5           \n\t"
+            // use mm0 mask copy to merge a & b
+            "pand %%mm0, %%mm2           \n\t"
+            "pandn %%mm4, %%mm7          \n\t"
+            "pandn %%mm1, %%mm0          \n\t"
+            "paddw %%mm5, %%mm7          \n\t"
+            "paddw %%mm2, %%mm0          \n\t"
+            //  test  ((pa <= pb)? pa:pb) <= pc
+            "pcmpgtw %%mm6, %%mm7        \n\t" // pab > pc?
+            "pxor %%mm1, %%mm1           \n\t"
+            "pand %%mm7, %%mm3           \n\t"
+            "pandn %%mm0, %%mm7          \n\t"
+            "paddw %%mm3, %%mm7          \n\t"
+            "pxor %%mm0, %%mm0           \n\t"
+            "packuswb %%mm1, %%mm7       \n\t"
+            "movq -8(%0," PCX ",), %%mm3 \n\t" // load c=Prior(x-bpp)
+            LOAD_GOT_rbp
+            "pand " AMASK4_4_0 ", %%mm7  \n\t" // _amask4_4_0 (was _ActiveMask)
+            RESTORE_rbp
+            "psrlq $16, %%mm3            \n\t"
+            "movq (%0," PCX ",), %%mm2   \n\t" // load b=Prior(x) step 1
+            "paddb (%1," PCX ",), %%mm7  \n\t" // add Paeth predictor + Raw(x)
+            "movq %%mm2, %%mm6           \n\t"
+            "movq %%mm7, (%1," PCX ",)   \n\t" // write back updated value
+            "movq -8(%1," PCX ",), %%mm1 \n\t"
+            "psllq $48, %%mm6            \n\t" // bpp * 8 = bits per pixel
+            "movq %%mm7, %%mm5           \n\t"
+            "psrlq $16, %%mm1            \n\t" // 64 - (bpp * 8) = remainder
+            "por %%mm6, %%mm3            \n\t"
+            "psllq $48, %%mm5            \n\t" // was _ShiftBpp
+            "punpckhbw %%mm0, %%mm3      \n\t" // unpack High bytes of c
+            "por %%mm5, %%mm1            \n\t"
+            // do second set of 4 bytes
+            "punpckhbw %%mm0, %%mm2      \n\t" // unpack High bytes of b
+            "punpckhbw %%mm0, %%mm1      \n\t" // unpack High bytes of a
+            // pav = p - a = (a + b - c) - a = b - c
+            "movq %%mm2, %%mm4           \n\t"
+            // pbv = p - b = (a + b - c) - b = a - c
+            "movq %%mm1, %%mm5           \n\t"
+            "psubw %%mm3, %%mm4          \n\t"
+            "pxor %%mm7, %%mm7           \n\t"
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+            "movq %%mm4, %%mm6           \n\t"
+            "psubw %%mm3, %%mm5          \n\t"
+            // pa = abs(p-a) = abs(pav)
+            // pb = abs(p-b) = abs(pbv)
+            // pc = abs(p-c) = abs(pcv)
+            "pcmpgtw %%mm4, %%mm0        \n\t" // create mask pav bytes < 0
+            "paddw %%mm5, %%mm6          \n\t"
+            "pand %%mm4, %%mm0           \n\t" // only pav bytes < 0 in mm7
+            "pcmpgtw %%mm5, %%mm7        \n\t" // create mask pbv bytes < 0
+            "psubw %%mm0, %%mm4          \n\t"
+            "pand %%mm5, %%mm7           \n\t" // only pbv bytes < 0 in mm0
+            "psubw %%mm0, %%mm4          \n\t"
+            "psubw %%mm7, %%mm5          \n\t"
+            "pxor %%mm0, %%mm0           \n\t"
+            "pcmpgtw %%mm6, %%mm0        \n\t" // create mask pcv bytes < 0
+            "pand %%mm6, %%mm0           \n\t" // only pav bytes < 0 in mm7
+            "psubw %%mm7, %%mm5          \n\t"
+            "psubw %%mm0, %%mm6          \n\t"
+            //  test pa <= pb
+            "movq %%mm4, %%mm7           \n\t"
+            "psubw %%mm0, %%mm6          \n\t"
+            "pcmpgtw %%mm5, %%mm7        \n\t" // pa > pb?
+            "movq %%mm7, %%mm0           \n\t"
+            // use mm7 mask to merge pa & pb
+            "pand %%mm7, %%mm5           \n\t"
+            // use mm0 mask copy to merge a & b
+            "pand %%mm0, %%mm2           \n\t"
+            "pandn %%mm4, %%mm7          \n\t"
+            "pandn %%mm1, %%mm0          \n\t"
+            "paddw %%mm5, %%mm7          \n\t"
+            "paddw %%mm2, %%mm0          \n\t"
+            //  test  ((pa <= pb)? pa:pb) <= pc
+            "pcmpgtw %%mm6, %%mm7        \n\t" // pab > pc?
+            "pxor %%mm1, %%mm1           \n\t"
+            "pand %%mm7, %%mm3           \n\t"
+            "pandn %%mm0, %%mm7          \n\t"
+            "pxor %%mm1, %%mm1           \n\t"
+            "paddw %%mm3, %%mm7          \n\t"
+            "pxor %%mm0, %%mm0           \n\t"
+            // step ecx to next set of 8 bytes and repeat loop til done
+            "addl $8, %%ecx              \n\t"
+            "packuswb %%mm7, %%mm1       \n\t"
+            "paddb -8(%1," PCX ",), %%mm1 \n\t" // add Paeth predictor + Raw(x)
+            "cmpl %%eax, %%ecx           \n\t" // MMXLength
+            "movq %%mm1, -8(%1," PCX ",) \n\t" // write back updated value
+                                 // mm1 will be used as Raw(x-bpp) next loop
+            "jb paeth_6lp                \n\t"
+
+            : "=S" (dummy_value_S),            // output regs (dummy)
+              "=D" (dummy_value_D),
+              "=c" (dummy_value_c),
+              "=a" (dummy_value_a)
+
+            : "0" (prev_row),  // esi/rsi      // input regs
+              "1" (row),       // edi/rdi
+              "2" (diff),      // ecx
+              "3" (MMXLength)  // eax
+
+#if defined(CLOBBER_MMX_REGS_SUPPORTED)
+            : "%mm0", "%mm1", "%mm2", "%mm3"   // clobber list
+            , "%mm4", "%mm5", "%mm6", "%mm7"
+#endif
+         );
+      }
+      break;  // end 6 bpp
+
+      case 8:                          // bpp == 8
+      {
+         __asm__ __volatile__ (
+// preload  "movl diff, %%ecx            \n\t"
+// preload  "movl row, %1                \n\t" // edi/rdi
+// preload  "movl prev_row, %0           \n\t" // esi/rsi
+            "pxor %%mm0, %%mm0           \n\t"
+            // prime the pump:  load the first Raw(x-bpp) data set
+            "movq -8(%1," PCX ",), %%mm1 \n\t" // only time should need to read
+                                               //  a=Raw(x-bpp) bytes
+         "paeth_8lp:                     \n\t"
+            // do first set of 4 bytes
+            "movq -8(%0," PCX ",), %%mm3 \n\t" // read c=Prior(x-bpp) bytes
+            "punpcklbw %%mm0, %%mm1      \n\t" // unpack Low bytes of a
+            "movq (%0," PCX ",), %%mm2   \n\t" // load b=Prior(x)
+            "punpcklbw %%mm0, %%mm2      \n\t" // unpack Low bytes of b
+            // pav = p - a = (a + b - c) - a = b - c
+            "movq %%mm2, %%mm4           \n\t"
+            "punpcklbw %%mm0, %%mm3      \n\t" // unpack Low bytes of c
+            // pbv = p - b = (a + b - c) - b = a - c
+            "movq %%mm1, %%mm5           \n\t"
+            "psubw %%mm3, %%mm4          \n\t"
+            "pxor %%mm7, %%mm7           \n\t"
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+            "movq %%mm4, %%mm6           \n\t"
+            "psubw %%mm3, %%mm5          \n\t"
+            // pa = abs(p-a) = abs(pav)
+            // pb = abs(p-b) = abs(pbv)
+            // pc = abs(p-c) = abs(pcv)
+            "pcmpgtw %%mm4, %%mm0        \n\t" // create mask pav bytes < 0
+            "paddw %%mm5, %%mm6          \n\t"
+            "pand %%mm4, %%mm0           \n\t" // only pav bytes < 0 in mm7
+            "pcmpgtw %%mm5, %%mm7        \n\t" // create mask pbv bytes < 0
+            "psubw %%mm0, %%mm4          \n\t"
+            "pand %%mm5, %%mm7           \n\t" // only pbv bytes < 0 in mm0
+            "psubw %%mm0, %%mm4          \n\t"
+            "psubw %%mm7, %%mm5          \n\t"
+            "pxor %%mm0, %%mm0           \n\t"
+            "pcmpgtw %%mm6, %%mm0        \n\t" // create mask pcv bytes < 0
+            "pand %%mm6, %%mm0           \n\t" // only pav bytes < 0 in mm7
+            "psubw %%mm7, %%mm5          \n\t"
+            "psubw %%mm0, %%mm6          \n\t"
+            //  test pa <= pb
+            "movq %%mm4, %%mm7           \n\t"
+            "psubw %%mm0, %%mm6          \n\t"
+            "pcmpgtw %%mm5, %%mm7        \n\t" // pa > pb?
+            "movq %%mm7, %%mm0           \n\t"
+            // use mm7 mask to merge pa & pb
+            "pand %%mm7, %%mm5           \n\t"
+            // use mm0 mask copy to merge a & b
+            "pand %%mm0, %%mm2           \n\t"
+            "pandn %%mm4, %%mm7          \n\t"
+            "pandn %%mm1, %%mm0          \n\t"
+            "paddw %%mm5, %%mm7          \n\t"
+            "paddw %%mm2, %%mm0          \n\t"
+            //  test  ((pa <= pb)? pa:pb) <= pc
+            "pcmpgtw %%mm6, %%mm7        \n\t" // pab > pc?
+            "pxor %%mm1, %%mm1           \n\t"
+            "pand %%mm7, %%mm3           \n\t"
+            "pandn %%mm0, %%mm7          \n\t"
+            "paddw %%mm3, %%mm7          \n\t"
+            "pxor %%mm0, %%mm0           \n\t"
+            "packuswb %%mm1, %%mm7       \n\t"
+            "movq -8(%0," PCX ",), %%mm3 \n\t" // read c=Prior(x-bpp) bytes
+            LOAD_GOT_rbp
+            "pand " AMASK4_4_0 ", %%mm7  \n\t" // _amask4_4_0 (was _ActiveMask)
+            RESTORE_rbp
+            "movq (%0," PCX ",), %%mm2   \n\t" // load b=Prior(x)
+            "paddb (%1," PCX ",), %%mm7  \n\t" // add Paeth predictor + Raw(x)
+            "punpckhbw %%mm0, %%mm3      \n\t" // unpack High bytes of c
+            "movq %%mm7, (%1," PCX ",)   \n\t" // write back updated value
+            "movq -8(%1," PCX ",), %%mm1 \n\t" // read a=Raw(x-bpp) bytes
+
+            // do second set of 4 bytes
+            "punpckhbw %%mm0, %%mm2      \n\t" // unpack High bytes of b
+            "punpckhbw %%mm0, %%mm1      \n\t" // unpack High bytes of a
+            // pav = p - a = (a + b - c) - a = b - c
+            "movq %%mm2, %%mm4           \n\t"
+            // pbv = p - b = (a + b - c) - b = a - c
+            "movq %%mm1, %%mm5           \n\t"
+            "psubw %%mm3, %%mm4          \n\t"
+            "pxor %%mm7, %%mm7           \n\t"
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+            "movq %%mm4, %%mm6           \n\t"
+            "psubw %%mm3, %%mm5          \n\t"
+            // pa = abs(p-a) = abs(pav)
+            // pb = abs(p-b) = abs(pbv)
+            // pc = abs(p-c) = abs(pcv)
+            "pcmpgtw %%mm4, %%mm0        \n\t" // create mask pav bytes < 0
+            "paddw %%mm5, %%mm6          \n\t"
+            "pand %%mm4, %%mm0           \n\t" // only pav bytes < 0 in mm7
+            "pcmpgtw %%mm5, %%mm7        \n\t" // create mask pbv bytes < 0
+            "psubw %%mm0, %%mm4          \n\t"
+            "pand %%mm5, %%mm7           \n\t" // only pbv bytes < 0 in mm0
+            "psubw %%mm0, %%mm4          \n\t"
+            "psubw %%mm7, %%mm5          \n\t"
+            "pxor %%mm0, %%mm0           \n\t"
+            "pcmpgtw %%mm6, %%mm0        \n\t" // create mask pcv bytes < 0
+            "pand %%mm6, %%mm0           \n\t" // only pav bytes < 0 in mm7
+            "psubw %%mm7, %%mm5          \n\t"
+            "psubw %%mm0, %%mm6          \n\t"
+            //  test pa <= pb
+            "movq %%mm4, %%mm7           \n\t"
+            "psubw %%mm0, %%mm6          \n\t"
+            "pcmpgtw %%mm5, %%mm7        \n\t" // pa > pb?
+            "movq %%mm7, %%mm0           \n\t"
+            // use mm7 mask to merge pa & pb
+            "pand %%mm7, %%mm5           \n\t"
+            // use mm0 mask copy to merge a & b
+            "pand %%mm0, %%mm2           \n\t"
+            "pandn %%mm4, %%mm7          \n\t"
+            "pandn %%mm1, %%mm0          \n\t"
+            "paddw %%mm5, %%mm7          \n\t"
+            "paddw %%mm2, %%mm0          \n\t"
+            //  test  ((pa <= pb)? pa:pb) <= pc
+            "pcmpgtw %%mm6, %%mm7        \n\t" // pab > pc?
+            "pxor %%mm1, %%mm1           \n\t"
+            "pand %%mm7, %%mm3           \n\t"
+            "pandn %%mm0, %%mm7          \n\t"
+            "pxor %%mm1, %%mm1           \n\t"
+            "paddw %%mm3, %%mm7          \n\t"
+            "pxor %%mm0, %%mm0           \n\t"
+            // step ecx to next set of 8 bytes and repeat loop til done
+            "addl $8, %%ecx              \n\t"
+            "packuswb %%mm7, %%mm1       \n\t"
+            "paddb -8(%1," PCX ",), %%mm1 \n\t" // add Paeth predictor + Raw(x)
+            "cmpl %%eax, %%ecx           \n\t" // MMXLength
+            "movq %%mm1, -8(%1," PCX ",) \n\t" // write back updated value
+                                 // mm1 will be used as Raw(x-bpp) next loop
+            "jb paeth_8lp                \n\t"
+
+            : "=S" (dummy_value_S),            // output regs (dummy)
+              "=D" (dummy_value_D),
+              "=c" (dummy_value_c),
+              "=a" (dummy_value_a)
+
+            : "0" (prev_row),  // esi/rsi      // input regs
+              "1" (row),       // edi/rdi
+              "2" (diff),      // ecx
+              "3" (MMXLength)  // eax
+
+#if defined(CLOBBER_MMX_REGS_SUPPORTED)
+            : "%mm0", "%mm1", "%mm2", "%mm3"   // clobber list
+            , "%mm4", "%mm5", "%mm6", "%mm7"
+#endif
+         );
+      }
+      break;  // end 8 bpp
+
+      default:                // bpp != 1,2,3,4,6,8:  doesn't exist
+      {
+         // ERROR:  SHOULD NEVER BE REACHED
+#if defined(PNG_DEBUG)
+         png_debug(1, "Internal libpng logic error (GCC "
+           "png_read_filter_row_mmx_paeth())\n");
+#endif
+      }
+      break;
+
+   } // end switch (bpp)
+
+   __asm__ __volatile__ (
+      // MMX acceleration complete; now do clean-up
+      // check if any remaining bytes left to decode
+//pre "movl FullLength, %%edx      \n\t"
+//pre "movl MMXLength, %%eax       \n\t"
+      "cmpl %%edx, %%eax           \n\t"
+      "jnb paeth_end               \n\t"
+
+      SAVE_ebp
+
+//pre "movl row, %2                \n\t" // edi/rdi
+//pre "movl prev_row, %1           \n\t" // esi/rsi
+      // do Paeth decode for remaining bytes
+      "movl %%eax, %%ebp           \n\t"
+//pre "subl bpp, %%ebp             \n\t" // (bpp is preloaded into ecx)
+      "subl %%ecx, %%ebp           \n\t" // ebp = eax - bpp
+      "xorl %%ecx, %%ecx           \n\t" // zero ecx before using cl & cx below
+
+      SAVE_GOT_ebx
+      SAVE_r11_r12_r13
+
+   "paeth_lp2:                     \n\t"
+      "xorl %%ebx, %%ebx           \n\t"
+      // pav = p - a = (a + b - c) - a = b - c
+      "movb (%1," PAX ",), %%bl    \n\t" // load Prior(x) into bl
+      "movb (%1," PBP ",), %%cl    \n\t" // load Prior(x-bpp) into cl
+      "subl %%ecx, %%ebx           \n\t" // subtract Prior(x-bpp)
+      "movl %%ebx, " pa_TEMP "     \n\t" // Save pav for later use
+      "xorl %%ebx, %%ebx           \n\t"
+      // pbv = p - b = (a + b - c) - b = a - c
+      "movb (%2," PBP ",), %%bl    \n\t" // load Raw(x-bpp) into bl
+      "subl %%ecx, %%ebx           \n\t" // subtract Prior(x-bpp)
+      "movl %%ebx, %%ecx           \n\t"
+      // pcv = p - c = (a + b - c) - c = (a - c) + (b - c) = pav + pbv
+      "addl " pa_TEMP ", %%ebx     \n\t" // pcv = pav + pbv
+      // pc = abs(pcv)
+      "testl $0x80000000, %%ebx    \n\t"
+      "jz paeth_pca2               \n\t"
+      "negl %%ebx                  \n\t" // reverse sign of neg values
+
+   "paeth_pca2:                    \n\t"
+      "movl %%ebx, " pc_TEMP "     \n\t" // save pc for later use
+      // pb = abs(pbv)
+      "testl $0x80000000, %%ecx    \n\t"
+      "jz paeth_pba2               \n\t"
+      "negl %%ecx                  \n\t" // reverse sign of neg values
+
+   "paeth_pba2:                    \n\t"
+      "movl %%ecx, " pb_TEMP "     \n\t" // save pb for later use
+      // pa = abs(pav)
+      "movl " pa_TEMP ", %%ebx     \n\t"
+      "testl $0x80000000, %%ebx    \n\t"
+      "jz paeth_paa2               \n\t"
+      "negl %%ebx                  \n\t" // reverse sign of neg values
+
+   "paeth_paa2:                    \n\t"
+      "movl %%ebx, " pa_TEMP "     \n\t" // save pa for later use
+      // test if pa <= pb
+      "cmpl %%ecx, %%ebx           \n\t"
+      "jna paeth_abb2              \n\t"
+      // pa > pb; now test if pb <= pc
+      "cmpl " pc_TEMP ", %%ecx     \n\t"
+      "jna paeth_bbc2              \n\t"
+      // pb > pc; Raw(x) = Paeth(x) + Prior(x-bpp)
+      "movb (%1," PBP ",), %%cl    \n\t" // load Prior(x-bpp) into cl
+      "jmp paeth_paeth2            \n\t"
+
+   "paeth_bbc2:                    \n\t"
+      // pb <= pc; Raw(x) = Paeth(x) + Prior(x)
+      "movb (%1," PAX ",), %%cl    \n\t" // load Prior(x) into cl
+      "jmp paeth_paeth2            \n\t"
+
+   "paeth_abb2:                    \n\t"
+      // pa <= pb; now test if pa <= pc
+      "cmpl " pc_TEMP ", %%ebx     \n\t"
+      "jna paeth_abc2              \n\t"
+      // pa > pc; Raw(x) = Paeth(x) + Prior(x-bpp)
+      "movb (%1," PBP ",), %%cl    \n\t" // load Prior(x-bpp) into cl
+      "jmp paeth_paeth2            \n\t"
+
+   "paeth_abc2:                    \n\t"
+      // pa <= pc; Raw(x) = Paeth(x) + Raw(x-bpp)
+      "movb (%2," PBP ",), %%cl    \n\t" // load Raw(x-bpp) into cl
+
+   "paeth_paeth2:                  \n\t"
+      "incl %%eax                  \n\t"
+      "incl %%ebp                  \n\t"
+      // Raw(x) = (Paeth(x) + Paeth_Predictor( a, b, c )) mod 256
+      "addb %%cl, -1(%2," PAX ",)  \n\t"
+      "cmpl %%edx, %%eax           \n\t" // check against FullLength
+      "jb paeth_lp2                \n\t"
+
+      RESTORE_r11_r12_r13
+      RESTORE_GOT_ebx
+      RESTORE_ebp
+
+   "paeth_end:                     \n\t"
+      "EMMS                        \n\t" // end MMX; prep for poss. FP instrs.
+
+      : "=c" (dummy_value_c),            // output regs (dummy)
+        "=S" (dummy_value_S),
+        "=D" (dummy_value_D),
+        "=a" (dummy_value_a),
+        "=d" (dummy_value_d)
+
+      : "0" (bpp),         // ecx        // input regs
+        "1" (prev_row),    // esi/rsi
+        "2" (row),         // edi/rdi
+        "3" (MMXLength),   // eax
+        "4" (FullLength)   // edx
+
+      CLOB_COLON_ebx_ebp_r1X             // clobber list
+        CLOBBER_GOT_ebx
+        CLOB_COMMA_ebx_ebp
+        CLOBBER_ebp
+        CLOB_COMMA_ebX_r1X
+        CLOBBER_r11_r12_r13
+   );
+
+} /* end png_read_filter_row_mmx_paeth() */
+
+#endif // PNG_x86_64_USE_GOTPCREL || PNG_THREAD_UNSAFE_OK
+#endif /* PNG_MMX_READ_FILTER_PAETH_SUPPORTED */
+
+
+
+
+#if defined(PNG_MMX_READ_FILTER_SUB_SUPPORTED)
+
+//===========================================================================//
+//                                                                           //
+//           P N G _ R E A D _ F I L T E R _ R O W _ M M X _ S U B           //
+//                                                                           //
+//===========================================================================//
+
+// Optimized code for PNG Sub filter decoder
+
+static void /* PRIVATE */
+png_read_filter_row_mmx_sub(png_row_infop row_info, png_bytep row)
+{
+   unsigned FullLength, MMXLength;  // png_uint_32 is actually 64-bit on x86-64
+   int bpp;
+   int dummy_value_a;
+   int dummy_value_c;
+   int dummy_value_d;
+   png_bytep dummy_value_D;
+   int diff; //     __attribute__((used));
+
+   bpp = (row_info->pixel_depth + 7) >> 3;  // calc number of bytes per pixel
+   FullLength = row_info->rowbytes - bpp;   // number of bytes to filter
+     // (why do we subtract off bpp?  not so in avg or paeth...)
+
+   __asm__ __volatile__ (
+      SAVE_r15
+      SAVE_ebp
+//pre "movl row, %1                \n\t" // edi/rdi
+      "mov  %1, " PSI "            \n\t" // lp = row
+//pre "movl bpp, %%ecx             \n\t"
+      "add  " PCX ", %1            \n\t" // rp = row + bpp
+//pre "movl FullLength, %%eax      \n\t" // bring in via eax...
+      SAVE_FullLength                    // ...but store for later use
+
+      "xorl %%eax, %%eax           \n\t"
+
+      // get # of bytes to alignment (note:  computing _delta_ of two pointers,
+      // so hereafter %%ebp is sufficient even on 64-bit)
+      "mov  %1, " PBP "            \n\t" // take start of row
+      "add  $0xf, " PBP "          \n\t" // add 7+8 to incr past alignment bdry
+//    "andl $0xfffffff8, %%ebp     \n\t" // mask to alignment boundary (32-bit!)
+      CLEAR_BOTTOM_3_BITS  PBP    "\n\t" // mask to alignment boundary
+      "sub  %1, " PBP "            \n\t" // subtract row ptr again => ebp =
+      "jz sub_go                   \n\t" //  target value of eax at alignment
+
+   "sub_lp1:                       \n\t" // fix alignment
+      "movb (" PSI "," PAX ",), %%cl \n\t"
+      "addb %%cl, (%1," PAX ",)    \n\t"
+      "incl %%eax                  \n\t"
+      "cmpl %%ebp, %%eax           \n\t"
+      "jb sub_lp1                  \n\t"
+
+   "sub_go:                        \n\t"
+      RESTORE_FullLength "%%ecx    \n\t" // FullLength -> ecx
+      "movl %%ecx, %%edx           \n\t"
+      "subl %%eax, %%edx           \n\t" // subtract alignment fix
+      "andl $0x00000007, %%edx     \n\t" // calc bytes over mult of 8
+      "subl %%edx, %%ecx           \n\t" // drop over bytes from length
+//out "movl %%ecx, MMXLength       \n\t"
+      "movl %%ebp, %%eax           \n\t" // ebp = diff, but no reg constraint(?)
+      RESTORE_ebp                        //  (could swap ebp and ecx functions,
+      RESTORE_r15                        //  but %%cl issues...)
+
+      : "=c" (MMXLength),       // 0     // output regs
+        "=D" (dummy_value_D),   // 1
+        "=a" (diff)             // 2
+
+      : "0" (bpp),              // ecx   // input regs
+        "1" (row),              // edi
+        "2" (FullLength)        // eax
+
+      : "%esi", "%edx"                   // clobber list
+        _CLOBBER_r15
+        _CLOBBER_ebp
+   );
+
+   // now do the math for the rest of the row
+   switch (bpp)
+   {
+      case 3:
+      {
+//       _ShiftBpp = 24;       // == 3 * 8
+//       _ShiftRem  = 40;      // == 64 - 24
+
+         __asm__ __volatile__ (
+// preload  "mov  row, %1                 \n\t" // edi/rdi
+            LOAD_GOT_rbp
+            // load (former) _ActiveMask for 2nd active byte group
+            "movq " AMASK2_3_3 ", %%mm7   \n\t" // _amask2_3_3
+            RESTORE_rbp
+
+// notused  "mov  %1, " PSI "             \n\t" // lp = row
+// preload  "movl bpp, %%ecx              \n\t"
+            "add  " PCX ", %1             \n\t" // rp = row + bpp
+            "movq %%mm7, %%mm6            \n\t"
+// preload  "movl diff, %%edx             \n\t"
+            "psllq $24, %%mm6             \n\t" // move mask in mm6 to cover
+                                                //  3rd active byte group
+            // prime the pump:  load the first Raw(x-bpp) data set
+            "movq -8(%1," PDX ",), %%mm1  \n\t"
+
+         "sub_3lp:                        \n\t" // shift data for adding first
+            "psrlq $40, %%mm1             \n\t" //  bpp bytes (no need for mask;
+                                                //  shift clears inactive bytes)
+            // add 1st active group
+            "movq (%1," PDX ",), %%mm0    \n\t"
+            "paddb %%mm1, %%mm0           \n\t"
+
+            // add 2nd active group
+            "movq %%mm0, %%mm1            \n\t" // mov updated Raws to mm1
+            "psllq $24, %%mm1             \n\t" // shift data to pos. correctly
+            "pand %%mm7, %%mm1            \n\t" // mask to use 2nd active group
+            "paddb %%mm1, %%mm0           \n\t"
+
+            // add 3rd active group
+            "movq %%mm0, %%mm1            \n\t" // mov updated Raws to mm1
+            "psllq $24, %%mm1             \n\t" // shift data to pos. correctly
+            "pand %%mm6, %%mm1            \n\t" // mask to use 3rd active group
+            "addl $8, %%edx               \n\t"
+            "paddb %%mm1, %%mm0           \n\t"
+
+            "cmpl %%eax, %%edx            \n\t" // MMXLength
+            "movq %%mm0, -8(%1," PDX ",)  \n\t" // write updated Raws to array
+            "movq %%mm0, %%mm1            \n\t" // prep 1st add at top of loop
+            "jb sub_3lp                   \n\t"
+
+            : "=c" (dummy_value_c),   // 0      // output regs (dummy)
+              "=D" (dummy_value_D),   // 1
+              "=d" (dummy_value_d),   // 2
+              "=a" (dummy_value_a)    // 3
+
+            : "0" (bpp),              // ecx    // input regs
+              "1" (row),              // edi
+              "2" (diff),             // edx
+              "3" (MMXLength)         // eax
+
+#if defined(CLOBBER_MMX_REGS_SUPPORTED)
+            : "%mm0", "%mm1", "%mm6", "%mm7"    // clobber list
+#endif
+         );
+      }
+      break;  // end 3 bpp
+
+      case 4:   // formerly shared with 6 bpp case via _ShiftBpp and _ShiftRem,
+      {         // but 64-bit PIC/.so problems (could still share, moving vars
+                // into unused MMX regs via ecx/edx, but kludgy)
+//       _ShiftBpp = bpp << 3;        // 32 (psllq)
+//       _ShiftRem = 64 - _ShiftBpp;  // 32 (psrlq)
+
+         __asm__ __volatile__ (
+// preload  "mov  row, %1                 \n\t" // edi/rdi
+// preload  "movl diff, %%edx             \n\t"
+// notused  "mov  %1, " PSI "             \n\t" // lp = row
+// preload  "movl bpp, %%ecx              \n\t"
+            "add  " PCX ", %1             \n\t" // rp = row + bpp
+
+            // prime the pump:  load the first Raw(x-bpp) data set
+            "movq -8(%1," PDX ",), %%mm1  \n\t"
+
+         "sub_4lp:                        \n\t" // shift data for adding first
+            "psrlq $32, %%mm1             \n\t" //  bpp bytes (no need for mask;
+                                                //  shift clears inactive bytes)
+            "movq (%1," PDX ",), %%mm0    \n\t"
+            "paddb %%mm1, %%mm0           \n\t"
+
+            // add 2nd active group
+            "movq %%mm0, %%mm1            \n\t" // mov updated Raws to mm1
+            "psllq $32, %%mm1             \n\t" // shift data to pos. correctly
+            "addl $8, %%edx               \n\t"
+            "paddb %%mm1, %%mm0           \n\t"
+
+            "cmpl %%eax, %%edx            \n\t" // MMXLength
+            "movq %%mm0, -8(%1," PDX ",)  \n\t" // write updated Raws to array
+            "movq %%mm0, %%mm1            \n\t" // prep 1st add at top of loop
+            "jb sub_4lp                   \n\t"
+
+            : "=c" (dummy_value_c),   // 0      // output regs (dummy)
+              "=D" (dummy_value_D),   // 1
+              "=d" (dummy_value_d),   // 2
+              "=a" (dummy_value_a)    // 3
+
+            : "0" (bpp),              // ecx    // input regs
+              "1" (row),              // edi
+              "2" (diff),             // edx
+              "3" (MMXLength)         // eax
+
+#if defined(CLOBBER_MMX_REGS_SUPPORTED)
+            : "%mm0", "%mm1"                    // clobber list
+#endif
+         );
+      }
+      break;  // end 4 bpp
+
+      case 1:
+      {
+         __asm__ __volatile__ (
+// preload  "movl diff, %%edx              \n\t"
+// preload  "mov  row, %1                  \n\t" // edi/rdi
+// preload  "cmpl FullLength, %%edx        \n\t"
+            "cmpl %%eax, %%edx             \n\t"
+            "jnb sub_1end                  \n\t"
+            "mov  %1, " PSI "              \n\t" // lp = row
+// irrel.   "xorl %%ecx, %%ecx             \n\t" // (actually bug with preload)
+// preload  "movl bpp, %%ecx               \n\t"
+            "add  " PCX ", %1              \n\t" // rp = row + bpp
+
+         "sub_1lp:                         \n\t"
+            "movb (" PSI "," PDX ",), %%cl \n\t"
+            "addb %%cl, (%1," PDX ",)      \n\t"
+            "incl %%edx                    \n\t"
+            "cmpl %%eax, %%edx             \n\t" // compare with FullLength
+            "jb sub_1lp                    \n\t"
+
+         "sub_1end:                        \n\t"
+
+            : "=c" (dummy_value_c),   // 0      // output regs (dummy)
+              "=D" (dummy_value_D),   // 1
+              "=d" (dummy_value_d),   // 2
+              "=a" (dummy_value_a)    // 3
+
+            : "0" (bpp),              // ecx    // input regs
+              "1" (row),              // edi
+              "2" (diff),             // edx
+              "3" (FullLength)        // eax
+
+            : "%esi"                            // clobber list
+         );
+      }
+      return;  // end 1 bpp (bypassing cleanup block!)
+
+      case 2:
+      {
+//       _ShiftBpp = 16;       // == 2 * 8
+//       _ShiftRem = 48;       // == 64 - 16
+
+         __asm__ __volatile__ (
+            LOAD_GOT_rbp
+            // load (former) _ActiveMask for 2nd active byte group
+            "movq " AMASK4_2_2 ", %%mm7   \n\t" // _amask4_2_2
+            RESTORE_rbp
+// preload  "movl diff, %%edx             \n\t"
+            "movq %%mm7, %%mm6            \n\t"
+// preload  "mov  row, %1                 \n\t" // edi/rdi
+            "psllq $16, %%mm6             \n\t" // move mask in mm6 to cover
+                                                //  3rd active byte group
+// notused  "mov  %1, " PSI "             \n\t" // lp = row
+            "movq %%mm6, %%mm5            \n\t"
+// preload  "movl bpp, %%ecx              \n\t"
+            "add  " PCX ", %1             \n\t" // rp = row + bpp
+            "psllq $16, %%mm5             \n\t" // move mask in mm5 to cover
+                                                //  4th active byte group
+            // prime the pump:  load the first Raw(x-bpp) data set
+            "movq -8(%1," PDX ",), %%mm1  \n\t"
+
+         "sub_2lp:                        \n\t" // shift data for adding first
+            "psrlq $48, %%mm1             \n\t" //  bpp bytes (no need for mask;
+                                                //  shift clears inactive bytes)
+            // add 1st active group
+            "movq (%1," PDX ",), %%mm0    \n\t"
+            "paddb %%mm1, %%mm0           \n\t"
+
+            // add 2nd active group
+            "movq %%mm0, %%mm1            \n\t" // mov updated Raws to mm1
+            "psllq $16, %%mm1             \n\t" // shift data to pos. correctly
+            "pand %%mm7, %%mm1            \n\t" // mask to use 2nd active group
+            "paddb %%mm1, %%mm0           \n\t"
+
+            // add 3rd active group
+            "movq %%mm0, %%mm1            \n\t" // mov updated Raws to mm1
+            "psllq $16, %%mm1             \n\t" // shift data to pos. correctly
+            "pand %%mm6, %%mm1            \n\t" // mask to use 3rd active group
+            "paddb %%mm1, %%mm0           \n\t"
+
+            // add 4th active group
+            "movq %%mm0, %%mm1            \n\t" // mov updated Raws to mm1
+            "psllq $16, %%mm1             \n\t" // shift data to pos. correctly
+            "pand %%mm5, %%mm1            \n\t" // mask to use 4th active group
+            "addl $8, %%edx               \n\t"
+            "paddb %%mm1, %%mm0           \n\t"
+            "cmpl %%eax, %%edx            \n\t" // MMXLength
+            "movq %%mm0, -8(%1," PDX ",)  \n\t" // write updated Raws to array
+            "movq %%mm0, %%mm1            \n\t" // prep 1st add at top of loop
+            "jb sub_2lp                   \n\t"
+
+            : "=c" (dummy_value_c),   // 0      // output regs (dummy)
+              "=D" (dummy_value_D),   // 1
+              "=d" (dummy_value_d),   // 2
+              "=a" (dummy_value_a)    // 3
+
+            : "0" (bpp),              // ecx    // input regs
+              "1" (row),              // edi
+              "2" (diff),             // edx
+              "3" (MMXLength)         // eax
+
+#if defined(CLOBBER_MMX_REGS_SUPPORTED)
+            : "%mm0", "%mm1", "%mm5", "%mm6"    // clobber list
+            , "%mm7"
+#endif
+         );
+      }
+      break;  // end 2 bpp
+
+      case 6:   // formerly shared with 4 bpp case (see comments there)
+      {
+//       _ShiftBpp = bpp << 3;        // 48 (psllq)
+//       _ShiftRem = 64 - _ShiftBpp;  // 16 (psrlq)
+
+         __asm__ __volatile__ (
+// preload  "mov  row, %1                 \n\t" // edi/rdi
+// preload  "movl diff, %%edx             \n\t"
+// notused  "mov  %1, " PSI "             \n\t" // lp = row
+// preload  "movl bpp, %%ecx              \n\t"
+            "add  " PCX ", %1             \n\t" // rp = row + bpp
+
+            // prime the pump:  load the first Raw(x-bpp) data set
+            "movq -8(%1," PDX ",), %%mm1  \n\t"
+
+         "sub_6lp:                        \n\t" // shift data for adding first
+            "psrlq $16, %%mm1             \n\t" //  bpp bytes (no need for mask;
+                                                //  shift clears inactive bytes)
+            "movq (%1," PDX ",), %%mm0    \n\t"
+            "paddb %%mm1, %%mm0           \n\t"
+
+            // add 2nd active group
+            "movq %%mm0, %%mm1            \n\t" // mov updated Raws to mm1
+            "psllq $48, %%mm1             \n\t" // shift data to pos. correctly
+            "addl $8, %%edx               \n\t"
+            "paddb %%mm1, %%mm0           \n\t"
+
+            "cmpl %%eax, %%edx            \n\t" // MMXLength
+            "movq %%mm0, -8(%1," PDX ",)  \n\t" // write updated Raws to array
+            "movq %%mm0, %%mm1            \n\t" // prep 1st add at top of loop
+            "jb sub_6lp                   \n\t"
+
+            : "=c" (dummy_value_c),   // 0      // output regs (dummy)
+              "=D" (dummy_value_D),   // 1
+              "=d" (dummy_value_d),   // 2
+              "=a" (dummy_value_a)    // 3
+
+            : "0" (bpp),              // ecx    // input regs
+              "1" (row),              // edi
+              "2" (diff),             // edx
+              "3" (MMXLength)         // eax
+
+#if defined(CLOBBER_MMX_REGS_SUPPORTED)
+            : "%mm0", "%mm1"                    // clobber list
+#endif
+         );
+      }
+      break;  // end 6 bpp
+
+      case 8:
+      {
+         __asm__ __volatile__ (
+// preload  "mov  row, %1                 \n\t" // edi/rdi
+// preload  "movl diff, %%edx             \n\t"
+// notused  "mov  %1, " PSI "             \n\t" // lp = row
+// preload  "movl bpp, %%ecx              \n\t"
+            "add  " PCX ", %1             \n\t" // rp = row + bpp
+// preload  "movl MMXLength, %%eax        \n\t"
+
+            // prime the pump:  load the first Raw(x-bpp) data set
+            "movq -8(%1," PDX ",), %%mm7  \n\t"
+            "movl %%eax, %%esi            \n\t" // copy of MMXLength -> esi
+            "andl $0x0000003f, %%esi      \n\t" // calc bytes over mult of 64
+
+         "sub_8lp:                        \n\t"
+            "movq (%1," PDX ",), %%mm0    \n\t" // load Sub(x) for 1st 8 bytes
+            "paddb %%mm7, %%mm0           \n\t"
+            "movq 8(%1," PDX ",), %%mm1   \n\t" // load Sub(x) for 2nd 8 bytes
+            "movq %%mm0, (%1," PDX ",)    \n\t" // write Raw(x) for 1st 8 bytes
+
+            // Now mm0 will be used as Raw(x-bpp) for the 2nd group of 8 bytes.
+            // This will be repeated for each group of 8 bytes with the 8th
+            // group being used as the Raw(x-bpp) for the 1st group of the
+            // next loop.
+
+            "paddb %%mm0, %%mm1           \n\t"
+            "movq 16(%1," PDX ",), %%mm2  \n\t" // load Sub(x) for 3rd 8 bytes
+            "movq %%mm1, 8(%1," PDX ",)   \n\t" // write Raw(x) for 2nd 8 bytes
+            "paddb %%mm1, %%mm2           \n\t"
+            "movq 24(%1," PDX ",), %%mm3  \n\t" // load Sub(x) for 4th 8 bytes
+            "movq %%mm2, 16(%1," PDX ",)  \n\t" // write Raw(x) for 3rd 8 bytes
+            "paddb %%mm2, %%mm3           \n\t"
+            "movq 32(%1," PDX ",), %%mm4  \n\t" // load Sub(x) for 5th 8 bytes
+            "movq %%mm3, 24(%1," PDX ",)  \n\t" // write Raw(x) for 4th 8 bytes
+            "paddb %%mm3, %%mm4           \n\t"
+            "movq 40(%1," PDX ",), %%mm5  \n\t" // load Sub(x) for 6th 8 bytes
+            "movq %%mm4, 32(%1," PDX ",)  \n\t" // write Raw(x) for 5th 8 bytes
+            "paddb %%mm4, %%mm5           \n\t"
+            "movq 48(%1," PDX ",), %%mm6  \n\t" // load Sub(x) for 7th 8 bytes
+            "movq %%mm5, 40(%1," PDX ",)  \n\t" // write Raw(x) for 6th 8 bytes
+            "paddb %%mm5, %%mm6           \n\t"
+            "movq 56(%1," PDX ",), %%mm7  \n\t" // load Sub(x) for 8th 8 bytes
+            "movq %%mm6, 48(%1," PDX ",)  \n\t" // write Raw(x) for 7th 8 bytes
+            "addl $64, %%edx              \n\t"
+            "paddb %%mm6, %%mm7           \n\t"
+            "cmpl %%esi, %%edx            \n\t" // cmp to bytes over mult of 64
+            "movq %%mm7, -8(%1," PDX ",)  \n\t" // write Raw(x) for 8th 8 bytes
+            "jb sub_8lp                   \n\t"
+
+            "cmpl %%eax, %%edx            \n\t" // compare to MMXLength
+            "jnb sub_8lt8                 \n\t"
+
+         "sub_8lpA:                       \n\t"
+            "movq (%1," PDX ",), %%mm0    \n\t"
+            "addl $8, %%edx               \n\t"
+            "paddb %%mm7, %%mm0           \n\t"
+            "cmpl %%eax, %%edx            \n\t" // compare to MMXLength
+            "movq %%mm0, -8(%1," PDX ",)  \n\t" // -8 to offset early addl edx
+            "movq %%mm0, %%mm7            \n\t" // move calculated Raw(x) data
+            "jb sub_8lpA                  \n\t" //  to mm7 to be new Raw(x-bpp)
+                                                //  for next loop
+         "sub_8lt8:                       \n\t"
+
+            : "=c" (dummy_value_c),   // 0      // output regs (dummy)
+              "=D" (dummy_value_D),   // 1
+              "=d" (dummy_value_d),   // 2
+              "=a" (dummy_value_a)    // 3
+
+            : "0" (bpp),              // ecx    // input regs
+              "1" (row),              // edi
+              "2" (diff),             // edx
+              "3" (MMXLength)         // eax
+
+            : "%esi"                            // clobber list
+#if defined(CLOBBER_MMX_REGS_SUPPORTED)
+            , "%mm0", "%mm1", "%mm2", "%mm3"
+            , "%mm4", "%mm5", "%mm6", "%mm7"
+#endif
+         );
+      }
+      break;  // end 8 bpp
+
+      default:                // bpp != 1,2,3,4,6,8:  doesn't exist
+      {
+         // ERROR:  SHOULD NEVER BE REACHED
+#if defined(PNG_DEBUG)
+         png_debug(1, "Internal libpng logic error (GCC "
+           "png_read_filter_row_mmx_sub())\n");
+#endif
+      }
+      break;
+
+   } // end switch (bpp)
+
+   __asm__ __volatile__ (
+//pre "movl MMXLength, %%eax         \n\t"
+//pre "mov  row, %1                  \n\t" // edi/rdi
+//pre "cmpl FullLength, %%eax        \n\t"
+      "cmpl %%edx, %%eax             \n\t"
+      "jnb sub_end                   \n\t"
+
+      "mov  %1, " PSI "              \n\t" // lp = row
+//pre "movl bpp, %%ecx               \n\t"
+      "add  " PCX ", %1              \n\t" // rp = row + bpp
+      "xorl %%ecx, %%ecx             \n\t"
+
+   "sub_lp2:                         \n\t"
+      "movb (" PSI "," PAX ",), %%cl \n\t"
+      "addb %%cl, (%1," PAX ",)      \n\t"
+      "incl %%eax                    \n\t"
+      "cmpl %%edx, %%eax             \n\t" // FullLength
+      "jb sub_lp2                    \n\t"
+
+   "sub_end:                         \n\t"
+      "EMMS                          \n\t" // end MMX instructions
+
+      : "=c" (dummy_value_c),   // 0      // output regs (dummy)
+        "=D" (dummy_value_D),   // 1
+        "=a" (dummy_value_a),   // 2
+        "=d" (dummy_value_d)    // 3
+
+      : "0" (bpp),              // ecx    // input regs
+        "1" (row),              // edi
+        "2" (MMXLength),        // eax
+        "3" (FullLength)        // edx
+
+      : "%esi"                            // clobber list
+   );
+
+} // end of png_read_filter_row_mmx_sub()
+
+#endif /* PNG_MMX_READ_FILTER_SUB_SUPPORTED */
+
+
+
+
+#if defined(PNG_MMX_READ_FILTER_UP_SUPPORTED)
+
+//===========================================================================//
+//                                                                           //
+//            P N G _ R E A D _ F I L T E R _ R O W _ M M X _ U P            //
+//                                                                           //
+//===========================================================================//
+
+// Optimized code for PNG Up filter decoder
+
+static void /* PRIVATE */
+png_read_filter_row_mmx_up(png_row_infop row_info, png_bytep row,
+                           png_bytep prev_row)
+{
+   unsigned len;        // png_uint_32 is actually 64-bit on x86-64
+   int dummy_value_d;   // fix 'forbidden register 3 (dx) was spilled' error
+   png_bytep dummy_value_S;
+   png_bytep dummy_value_D;
+
+   len = row_info->rowbytes;              // number of bytes to filter
+
+   __asm__ __volatile__ (
+      SAVE_GOT_ebx
+//pre "mov  prev_row, %1           \n\t" // esi/rsi
+//pre "movl row, %2                \n\t" // edi/rdi
+
+      "xorl %%ebx, %%ebx           \n\t"
+      "xorl %%eax, %%eax           \n\t"
+
+      // get # of bytes to alignment (note:  computing _delta_ of two pointers,
+      // so hereafter %%ecx is sufficient even on 64-bit)
+      "mov  %2, " PCX "            \n\t" // take start of row
+      "add  $0x7, " PCX "          \n\t" // add 7 to incr past alignment bdry
+//    "andl $0xfffffff8, %%ecx     \n\t" // mask to alignment boundary (32-bit!)
+      CLEAR_BOTTOM_3_BITS  PCX    "\n\t" // mask to alignment boundary
+      "sub  %2, " PCX "            \n\t" // subtract row ptr again => ebp =
+      "jz up_go                    \n\t" //  target value of ecx at alignment
+
+   "up_lp1:                        \n\t" // fix alignment
+      "movb (%2," PBX ",), %%al    \n\t"
+      "addb (%1," PBX ",), %%al    \n\t"
+      "incl %%ebx                  \n\t"
+      "cmpl %%ecx, %%ebx           \n\t"
+      "movb %%al, -1(%2," PBX ",)  \n\t" // mov does not affect flags; -1 to
+      "jb up_lp1                   \n\t" //  offset incl ebx
+
+   "up_go:                         \n\t"
+//pre "movl len, %%edx             \n\t"
+      "movl %%edx, %%ecx           \n\t"
+      "subl %%ebx, %%edx           \n\t" // subtract alignment fix
+      "andl $0x0000003f, %%edx     \n\t" // calc bytes over mult of 64
+      "subl %%edx, %%ecx           \n\t" // sub over-bytes from original length
+
+      // unrolled loop - use all MMX registers and interleave to reduce
+      // number of branch instructions (loops) and reduce partial stalls
+   "up_loop:                       \n\t"
+      "movq (%1," PBX ",), %%mm1   \n\t"
+      "movq (%2," PBX ",), %%mm0   \n\t"
+      "movq 8(%1," PBX ",), %%mm3  \n\t"
+      "paddb %%mm1, %%mm0          \n\t"
+      "movq 8(%2," PBX ",), %%mm2  \n\t"
+      "movq %%mm0, (%2," PBX ",)   \n\t"
+      "paddb %%mm3, %%mm2          \n\t"
+      "movq 16(%1," PBX ",), %%mm5 \n\t"
+      "movq %%mm2, 8(%2," PBX ",)  \n\t"
+      "movq 16(%2," PBX ",), %%mm4 \n\t"
+      "movq 24(%1," PBX ",), %%mm7 \n\t"
+      "paddb %%mm5, %%mm4          \n\t"
+      "movq 24(%2," PBX ",), %%mm6 \n\t"
+      "movq %%mm4, 16(%2," PBX ",) \n\t"
+      "paddb %%mm7, %%mm6          \n\t"
+      "movq 32(%1," PBX ",), %%mm1 \n\t"
+      "movq %%mm6, 24(%2," PBX ",) \n\t"
+      "movq 32(%2," PBX ",), %%mm0 \n\t"
+      "movq 40(%1," PBX ",), %%mm3 \n\t"
+      "paddb %%mm1, %%mm0          \n\t"
+      "movq 40(%2," PBX ",), %%mm2 \n\t"
+      "movq %%mm0, 32(%2," PBX ",) \n\t"
+      "paddb %%mm3, %%mm2          \n\t"
+      "movq 48(%1," PBX ",), %%mm5 \n\t"
+      "movq %%mm2, 40(%2," PBX ",) \n\t"
+      "movq 48(%2," PBX ",), %%mm4 \n\t"
+      "movq 56(%1," PBX ",), %%mm7 \n\t"
+      "paddb %%mm5, %%mm4          \n\t"
+      "movq 56(%2," PBX ",), %%mm6 \n\t"
+      "movq %%mm4, 48(%2," PBX ",) \n\t"
+      "addl $64, %%ebx             \n\t"
+      "paddb %%mm7, %%mm6          \n\t"
+      "cmpl %%ecx, %%ebx           \n\t"
+      "movq %%mm6, -8(%2," PBX ",) \n\t" // (+56)movq does not affect flags;
+      "jb up_loop                  \n\t" //  -8 to offset addl ebx
+
+      "cmpl $0, %%edx              \n\t" // test for bytes over mult of 64
+      "jz up_end                   \n\t"
+
+      "cmpl $8, %%edx              \n\t" // test for less than 8 bytes
+      "jb up_lt8                   \n\t" //  [added by lcreeve at netins.net]
+
+      "addl %%edx, %%ecx           \n\t"
+      "andl $0x00000007, %%edx     \n\t" // calc bytes over mult of 8
+      "subl %%edx, %%ecx           \n\t" // drop over-bytes from length
+      "jz up_lt8                   \n\t"
+
+   "up_lpA:                        \n\t" // use MMX regs to update 8 bytes sim.
+      "movq (%1," PBX ",), %%mm1   \n\t"
+      "movq (%2," PBX ",), %%mm0   \n\t"
+      "addl $8, %%ebx              \n\t"
+      "paddb %%mm1, %%mm0          \n\t"
+      "cmpl %%ecx, %%ebx           \n\t"
+      "movq %%mm0, -8(%2," PBX ",) \n\t" // movq does not affect flags; -8 to
+      "jb up_lpA                   \n\t" //  offset add ebx
+      "cmpl $0, %%edx              \n\t" // test for bytes over mult of 8
+      "jz up_end                   \n\t"
+
+   "up_lt8:                        \n\t"
+      "xorl %%eax, %%eax           \n\t"
+      "addl %%edx, %%ecx           \n\t" // move over byte count into counter
+
+   "up_lp2:                        \n\t" // use x86 regs for remaining bytes
+      "movb (%2," PBX ",), %%al    \n\t"
+      "addb (%1," PBX ",), %%al    \n\t"
+      "incl %%ebx                  \n\t"
+      "cmpl %%ecx, %%ebx           \n\t"
+      "movb %%al, -1(%2," PBX ",)  \n\t" // mov does not affect flags; -1 to
+      "jb up_lp2                   \n\t" //  offset inc ebx
+
+   "up_end:                        \n\t"
+      "EMMS                        \n\t" // conversion of filtered row complete
+      RESTORE_GOT_ebx
+
+      : "=d" (dummy_value_d),   // 0     // output regs (dummy)
+        "=S" (dummy_value_S),   // 1
+        "=D" (dummy_value_D)    // 2
+
+      : "0" (len),              // edx   // input regs
+        "1" (prev_row),         // esi
+        "2" (row)               // edi
+
+      : "%eax", "%ecx"                   // clobber list (no input regs!)
+        _CLOBBER_GOT_ebx
+#if defined(PNG_CLOBBER_MMX_REGS_SUPPORTED)
+      , "%mm0", "%mm1", "%mm2", "%mm3"
+      , "%mm4", "%mm5", "%mm6", "%mm7"
+#endif
+   );
+
+} // end of png_read_filter_row_mmx_up()
+
+#endif /* PNG_MMX_READ_FILTER_UP_SUPPORTED */
+
+
+
+
+/*===========================================================================*/
+/*                                                                           */
+/*                   P N G _ R E A D _ F I L T E R _ R O W                   */
+/*                                                                           */
+/*===========================================================================*/
+
+/* Optimized png_read_filter_row routines */
+
+void /* PRIVATE */
+png_read_filter_row(png_structp png_ptr, png_row_infop row_info, png_bytep
+   row, png_bytep prev_row, int filter)
+{
+#if defined(PNG_DEBUG)
+   char filtname[10];
+#endif
+
+   if (_mmx_supported == 2) {
+#if !defined(PNG_1_0_X)
+       /* this should have happened in png_init_mmx_flags() already */
+       png_warning(png_ptr, "asm_flags may not have been initialized");
+#endif
+       png_mmx_support();
+   }
+
+#if defined(PNG_DEBUG)
+   png_debug(1, "in png_read_filter_row (pnggccrd.c)\n");
+   switch (filter)
+   {
+      case 0:
+         png_snprintf(filtname, 10, "none");
+         break;
+
+      case 1:
+         png_snprintf(filtname, 10, "sub-%s",
+#ifdef PNG_MMX_READ_FILTER_SUB_SUPPORTED
+#if !defined(PNG_1_0_X)
+           ((png_ptr->asm_flags & PNG_ASM_FLAG_MMX_READ_FILTER_SUB) &&
+            (row_info->pixel_depth >= png_ptr->mmx_bitdepth_threshold) &&
+            (row_info->rowbytes >= png_ptr->mmx_rowbytes_threshold))
+#else
+           _mmx_supported
+#endif
+           ? "MMX" :
+#endif
+           "C");
+         break;
+
+      case 2:
+         png_snprintf(filtname, 10, "up-%s",
+#ifdef PNG_MMX_READ_FILTER_UP_SUPPORTED
+#if !defined(PNG_1_0_X)
+           ((png_ptr->asm_flags & PNG_ASM_FLAG_MMX_READ_FILTER_UP) &&
+            (row_info->pixel_depth >= png_ptr->mmx_bitdepth_threshold) &&
+            (row_info->rowbytes >= png_ptr->mmx_rowbytes_threshold))
+#else
+           _mmx_supported
+#endif
+           ? "MMX" :
+#endif
+           "C");
+         break;
+
+      case 3:
+         png_snprintf(filtname, 10, "avg-%s",
+#ifdef PNG_MMX_READ_FILTER_AVG_SUPPORTED
+#if !defined(PNG_1_0_X)
+           ((png_ptr->asm_flags & PNG_ASM_FLAG_MMX_READ_FILTER_AVG) &&
+            (row_info->pixel_depth >= png_ptr->mmx_bitdepth_threshold) &&
+            (row_info->rowbytes >= png_ptr->mmx_rowbytes_threshold))
+#else
+           _mmx_supported
+#endif
+           ? "MMX" :
+#endif
+           "C");
+         break;
+
+      case 4:
+         png_snprintf(filtname, 10, "paeth-%s",
+#ifdef PNG_MMX_READ_FILTER_PAETH_SUPPORTED
+#if defined(PNG_x86_64_USE_GOTPCREL) || defined(PNG_THREAD_UNSAFE_OK)
+#if !defined(PNG_1_0_X)
+           ((png_ptr->asm_flags & PNG_ASM_FLAG_MMX_READ_FILTER_PAETH) &&
+            (row_info->pixel_depth >= png_ptr->mmx_bitdepth_threshold) &&
+            (row_info->rowbytes >= png_ptr->mmx_rowbytes_threshold))
+#else
+           _mmx_supported
+#endif
+           ? "MMX" :
+#endif /* PNG_x86_64_USE_GOTPCREL || PNG_THREAD_UNSAFE_OK */
+#endif
+           "C");
+         break;
+
+      default:
+         png_snprintf(filtname, 10, "unknown");
+         break;
+   }
+   png_debug2(2, "row_number=%ld, %s, ", png_ptr->row_number, filtname);
+   //png_debug1(0, "png_ptr=%10p, ", png_ptr);
+   //png_debug1(0, "asm_flags=0x%08lx, ", png_ptr->asm_flags);
+   png_debug1(0, "row=%10p, ", row);
+   png_debug2(0, "pixdepth=%d, bytes=%d, ", (int)row_info->pixel_depth,
+      (int)((row_info->pixel_depth + 7) >> 3));
+   png_debug1(0, "rowbytes=%ld\n", row_info->rowbytes);
+#endif /* PNG_DEBUG */
+
+   switch (filter)
+   {
+      case PNG_FILTER_VALUE_NONE:
+         break;
+
+      case PNG_FILTER_VALUE_SUB:
+#ifdef PNG_MMX_READ_FILTER_SUB_SUPPORTED
+#if !defined(PNG_1_0_X)
+         if ((png_ptr->asm_flags & PNG_ASM_FLAG_MMX_READ_FILTER_SUB) &&
+             (row_info->pixel_depth >= png_ptr->mmx_bitdepth_threshold) &&
+             (row_info->rowbytes >= png_ptr->mmx_rowbytes_threshold))
+#else
+         if (_mmx_supported)
+#endif
+         {
+            png_read_filter_row_mmx_sub(row_info, row);
+         }
+         else
+#endif
+         {
+            png_uint_32 i;
+            png_uint_32 istop = row_info->rowbytes;
+            png_uint_32 bpp = (row_info->pixel_depth + 7) >> 3;
+            png_bytep rp = row + bpp;
+            png_bytep lp = row;
+
+            for (i = bpp; i < istop; i++)
+            {
+               *rp = (png_byte)(((int)(*rp) + (int)(*lp++)) & 0xff);
+               rp++;
+            }
+         }  /* end !UseMMX_sub */
+         break;
+
+      case PNG_FILTER_VALUE_UP:
+#ifdef PNG_MMX_READ_FILTER_UP_SUPPORTED
+#if !defined(PNG_1_0_X)
+         if ((png_ptr->asm_flags & PNG_ASM_FLAG_MMX_READ_FILTER_UP) &&
+             (row_info->pixel_depth >= png_ptr->mmx_bitdepth_threshold) &&
+             (row_info->rowbytes >= png_ptr->mmx_rowbytes_threshold))
+#else
+         if (_mmx_supported)
+#endif
+         {
+            png_read_filter_row_mmx_up(row_info, row, prev_row);
+         }
+          else
+#endif
+         {
+            png_uint_32 i;
+            png_uint_32 istop = row_info->rowbytes;
+            png_bytep rp = row;
+            png_bytep pp = prev_row;
+
+            for (i = 0; i < istop; ++i)
+            {
+               *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
+               rp++;
+            }
+         }  /* end !UseMMX_up */
+         break;
+
+      case PNG_FILTER_VALUE_AVG:
+#ifdef PNG_MMX_READ_FILTER_AVG_SUPPORTED
+#if !defined(PNG_1_0_X)
+         if ((png_ptr->asm_flags & PNG_ASM_FLAG_MMX_READ_FILTER_AVG) &&
+             (row_info->pixel_depth >= png_ptr->mmx_bitdepth_threshold) &&
+             (row_info->rowbytes >= png_ptr->mmx_rowbytes_threshold))
+#else
+         if (_mmx_supported)
+#endif
+         {
+            png_read_filter_row_mmx_avg(row_info, row, prev_row);
+         }
+         else
+#endif
+         {
+            png_uint_32 i;
+            png_bytep rp = row;
+            png_bytep pp = prev_row;
+            png_bytep lp = row;
+            png_uint_32 bpp = (row_info->pixel_depth + 7) >> 3;
+            png_uint_32 istop = row_info->rowbytes - bpp;
+
+            for (i = 0; i < bpp; i++)
+            {
+               *rp = (png_byte)(((int)(*rp) +
+                  ((int)(*pp++) >> 1)) & 0xff);
+               rp++;
+            }
+
+            for (i = 0; i < istop; i++)
+            {
+               *rp = (png_byte)(((int)(*rp) +
+                  ((int)(*pp++ + *lp++) >> 1)) & 0xff);
+               rp++;
+            }
+         }  /* end !UseMMX_avg */
+         break;
+
+      case PNG_FILTER_VALUE_PAETH:
+#ifdef PNG_MMX_READ_FILTER_PAETH_SUPPORTED
+#if defined(PNG_x86_64_USE_GOTPCREL) || defined(PNG_THREAD_UNSAFE_OK)
+#if !defined(PNG_1_0_X)
+         if ((png_ptr->asm_flags & PNG_ASM_FLAG_MMX_READ_FILTER_PAETH) &&
+             (row_info->pixel_depth >= png_ptr->mmx_bitdepth_threshold) &&
+             (row_info->rowbytes >= png_ptr->mmx_rowbytes_threshold))
+#else
+         if (_mmx_supported)
+#endif
+         {
+            png_read_filter_row_mmx_paeth(row_info, row, prev_row);
+         }
+         else
+#endif /* PNG_x86_64_USE_GOTPCREL || PNG_THREAD_UNSAFE_OK */
+#endif
+         {
+            png_uint_32 i;
+            png_bytep rp = row;
+            png_bytep pp = prev_row;
+            png_bytep lp = row;
+            png_bytep cp = prev_row;
+            png_uint_32 bpp = (row_info->pixel_depth + 7) >> 3;
+            png_uint_32 istop = row_info->rowbytes - bpp;
+
+            for (i = 0; i < bpp; i++)
+            {
+               *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
+               rp++;
+            }
+
+            for (i = 0; i < istop; i++)   /* use leftover rp,pp */
+            {
+               int a, b, c, pa, pb, pc, p;
+
+               a = *lp++;
+               b = *pp++;
+               c = *cp++;
+
+               p = b - c;
+               pc = a - c;
+
+#if defined(PNG_USE_ABS)
+               pa = abs(p);
+               pb = abs(pc);
+               pc = abs(p + pc);
+#else
+               pa = p < 0 ? -p : p;
+               pb = pc < 0 ? -pc : pc;
+               pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+#endif
+
+               /*
+                  if (pa <= pb && pa <= pc)
+                     p = a;
+                  else if (pb <= pc)
+                     p = b;
+                  else
+                     p = c;
+                */
+
+               p = (pa <= pb && pa <= pc) ? a : (pb <= pc) ? b : c;
+
+               *rp = (png_byte)(((int)(*rp) + p) & 0xff);
+               rp++;
+            }
+         }  /* end !UseMMX_paeth */
+         break;
+
+      default:
+         png_warning(png_ptr, "Ignoring bad row-filter type");
+         *row=0;
+         break;
+   }
+}
+
+#endif /* PNG_HAVE_MMX_READ_FILTER_ROW */
+
+
+#endif /* PNG_ASSEMBLER_CODE_SUPPORTED && PNG_USE_PNGGCCRD */
+#endif /* __GNUC__ */
diff --git a/distrib/libpng-1.2.19/pngget.c b/distrib/libpng-1.2.19/pngget.c
new file mode 100644
index 0000000..75d2ca0
--- /dev/null
+++ b/distrib/libpng-1.2.19/pngget.c
@@ -0,0 +1,962 @@
+
+/* pngget.c - retrieval of values from info struct
+ *
+ * Last changed in libpng 1.2.15 January 5, 2007
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1998-2007 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ */
+
+#define PNG_INTERNAL
+#include "png.h"
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+
+png_uint_32 PNGAPI
+png_get_valid(png_structp png_ptr, png_infop info_ptr, png_uint_32 flag)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return(info_ptr->valid & flag);
+   else
+      return(0);
+}
+
+png_uint_32 PNGAPI
+png_get_rowbytes(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return(info_ptr->rowbytes);
+   else
+      return(0);
+}
+
+#if defined(PNG_INFO_IMAGE_SUPPORTED)
+png_bytepp PNGAPI
+png_get_rows(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return(info_ptr->row_pointers);
+   else
+      return(0);
+}
+#endif
+
+#ifdef PNG_EASY_ACCESS_SUPPORTED
+/* easy access to info, added in libpng-0.99 */
+png_uint_32 PNGAPI
+png_get_image_width(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+   {
+      return info_ptr->width;
+   }
+   return (0);
+}
+
+png_uint_32 PNGAPI
+png_get_image_height(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+   {
+      return info_ptr->height;
+   }
+   return (0);
+}
+
+png_byte PNGAPI
+png_get_bit_depth(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+   {
+      return info_ptr->bit_depth;
+   }
+   return (0);
+}
+
+png_byte PNGAPI
+png_get_color_type(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+   {
+      return info_ptr->color_type;
+   }
+   return (0);
+}
+
+png_byte PNGAPI
+png_get_filter_type(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+   {
+      return info_ptr->filter_type;
+   }
+   return (0);
+}
+
+png_byte PNGAPI
+png_get_interlace_type(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+   {
+      return info_ptr->interlace_type;
+   }
+   return (0);
+}
+
+png_byte PNGAPI
+png_get_compression_type(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+   {
+      return info_ptr->compression_type;
+   }
+   return (0);
+}
+
+png_uint_32 PNGAPI
+png_get_x_pixels_per_meter(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+#if defined(PNG_pHYs_SUPPORTED)
+   if (info_ptr->valid & PNG_INFO_pHYs)
+   {
+      png_debug1(1, "in %s retrieval function\n", "png_get_x_pixels_per_meter");
+      if(info_ptr->phys_unit_type != PNG_RESOLUTION_METER)
+          return (0);
+      else return (info_ptr->x_pixels_per_unit);
+   }
+#else
+   return (0);
+#endif
+   return (0);
+}
+
+png_uint_32 PNGAPI
+png_get_y_pixels_per_meter(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+#if defined(PNG_pHYs_SUPPORTED)
+   if (info_ptr->valid & PNG_INFO_pHYs)
+   {
+      png_debug1(1, "in %s retrieval function\n", "png_get_y_pixels_per_meter");
+      if(info_ptr->phys_unit_type != PNG_RESOLUTION_METER)
+          return (0);
+      else return (info_ptr->y_pixels_per_unit);
+   }
+#else
+   return (0);
+#endif
+   return (0);
+}
+
+png_uint_32 PNGAPI
+png_get_pixels_per_meter(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+#if defined(PNG_pHYs_SUPPORTED)
+   if (info_ptr->valid & PNG_INFO_pHYs)
+   {
+      png_debug1(1, "in %s retrieval function\n", "png_get_pixels_per_meter");
+      if(info_ptr->phys_unit_type != PNG_RESOLUTION_METER ||
+         info_ptr->x_pixels_per_unit != info_ptr->y_pixels_per_unit)
+          return (0);
+      else return (info_ptr->x_pixels_per_unit);
+   }
+#else
+   return (0);
+#endif
+   return (0);
+}
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+float PNGAPI
+png_get_pixel_aspect_ratio(png_structp png_ptr, png_infop info_ptr)
+   {
+   if (png_ptr != NULL && info_ptr != NULL)
+#if defined(PNG_pHYs_SUPPORTED)
+   if (info_ptr->valid & PNG_INFO_pHYs)
+   {
+      png_debug1(1, "in %s retrieval function\n", "png_get_aspect_ratio");
+      if (info_ptr->x_pixels_per_unit == 0)
+         return ((float)0.0);
+      else
+         return ((float)((float)info_ptr->y_pixels_per_unit
+            /(float)info_ptr->x_pixels_per_unit));
+   }
+#else
+   return (0.0);
+#endif
+   return ((float)0.0);
+}
+#endif
+
+png_int_32 PNGAPI
+png_get_x_offset_microns(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+#if defined(PNG_oFFs_SUPPORTED)
+   if (info_ptr->valid & PNG_INFO_oFFs)
+   {
+      png_debug1(1, "in %s retrieval function\n", "png_get_x_offset_microns");
+      if(info_ptr->offset_unit_type != PNG_OFFSET_MICROMETER)
+          return (0);
+      else return (info_ptr->x_offset);
+   }
+#else
+   return (0);
+#endif
+   return (0);
+}
+
+png_int_32 PNGAPI
+png_get_y_offset_microns(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+#if defined(PNG_oFFs_SUPPORTED)
+   if (info_ptr->valid & PNG_INFO_oFFs)
+   {
+      png_debug1(1, "in %s retrieval function\n", "png_get_y_offset_microns");
+      if(info_ptr->offset_unit_type != PNG_OFFSET_MICROMETER)
+          return (0);
+      else return (info_ptr->y_offset);
+   }
+#else
+   return (0);
+#endif
+   return (0);
+}
+
+png_int_32 PNGAPI
+png_get_x_offset_pixels(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+#if defined(PNG_oFFs_SUPPORTED)
+   if (info_ptr->valid & PNG_INFO_oFFs)
+   {
+      png_debug1(1, "in %s retrieval function\n", "png_get_x_offset_microns");
+      if(info_ptr->offset_unit_type != PNG_OFFSET_PIXEL)
+          return (0);
+      else return (info_ptr->x_offset);
+   }
+#else
+   return (0);
+#endif
+   return (0);
+}
+
+png_int_32 PNGAPI
+png_get_y_offset_pixels(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+#if defined(PNG_oFFs_SUPPORTED)
+   if (info_ptr->valid & PNG_INFO_oFFs)
+   {
+      png_debug1(1, "in %s retrieval function\n", "png_get_y_offset_microns");
+      if(info_ptr->offset_unit_type != PNG_OFFSET_PIXEL)
+          return (0);
+      else return (info_ptr->y_offset);
+   }
+#else
+   return (0);
+#endif
+   return (0);
+}
+
+#if defined(PNG_INCH_CONVERSIONS) && defined(PNG_FLOATING_POINT_SUPPORTED)
+png_uint_32 PNGAPI
+png_get_pixels_per_inch(png_structp png_ptr, png_infop info_ptr)
+{
+   return ((png_uint_32)((float)png_get_pixels_per_meter(png_ptr, info_ptr)
+     *.0254 +.5));
+}
+
+png_uint_32 PNGAPI
+png_get_x_pixels_per_inch(png_structp png_ptr, png_infop info_ptr)
+{
+   return ((png_uint_32)((float)png_get_x_pixels_per_meter(png_ptr, info_ptr)
+     *.0254 +.5));
+}
+
+png_uint_32 PNGAPI
+png_get_y_pixels_per_inch(png_structp png_ptr, png_infop info_ptr)
+{
+   return ((png_uint_32)((float)png_get_y_pixels_per_meter(png_ptr, info_ptr)
+     *.0254 +.5));
+}
+
+float PNGAPI
+png_get_x_offset_inches(png_structp png_ptr, png_infop info_ptr)
+{
+   return ((float)png_get_x_offset_microns(png_ptr, info_ptr)
+     *.00003937);
+}
+
+float PNGAPI
+png_get_y_offset_inches(png_structp png_ptr, png_infop info_ptr)
+{
+   return ((float)png_get_y_offset_microns(png_ptr, info_ptr)
+     *.00003937);
+}
+
+#if defined(PNG_pHYs_SUPPORTED)
+png_uint_32 PNGAPI
+png_get_pHYs_dpi(png_structp png_ptr, png_infop info_ptr,
+   png_uint_32 *res_x, png_uint_32 *res_y, int *unit_type)
+{
+   png_uint_32 retval = 0;
+
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
+   {
+      png_debug1(1, "in %s retrieval function\n", "pHYs");
+      if (res_x != NULL)
+      {
+         *res_x = info_ptr->x_pixels_per_unit;
+         retval |= PNG_INFO_pHYs;
+      }
+      if (res_y != NULL)
+      {
+         *res_y = info_ptr->y_pixels_per_unit;
+         retval |= PNG_INFO_pHYs;
+      }
+      if (unit_type != NULL)
+      {
+         *unit_type = (int)info_ptr->phys_unit_type;
+         retval |= PNG_INFO_pHYs;
+         if(*unit_type == 1)
+         {
+            if (res_x != NULL) *res_x = (png_uint_32)(*res_x * .0254 + .50);
+            if (res_y != NULL) *res_y = (png_uint_32)(*res_y * .0254 + .50);
+         }
+      }
+   }
+   return (retval);
+}
+#endif /* PNG_pHYs_SUPPORTED */
+#endif  /* PNG_INCH_CONVERSIONS && PNG_FLOATING_POINT_SUPPORTED */
+
+/* png_get_channels really belongs in here, too, but it's been around longer */
+
+#endif  /* PNG_EASY_ACCESS_SUPPORTED */
+
+png_byte PNGAPI
+png_get_channels(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return(info_ptr->channels);
+   else
+      return (0);
+}
+
+png_bytep PNGAPI
+png_get_signature(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr != NULL && info_ptr != NULL)
+      return(info_ptr->signature);
+   else
+      return (NULL);
+}
+
+#if defined(PNG_bKGD_SUPPORTED)
+png_uint_32 PNGAPI
+png_get_bKGD(png_structp png_ptr, png_infop info_ptr,
+   png_color_16p *background)
+{
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD)
+      && background != NULL)
+   {
+      png_debug1(1, "in %s retrieval function\n", "bKGD");
+      *background = &(info_ptr->background);
+      return (PNG_INFO_bKGD);
+   }
+   return (0);
+}
+#endif
+
+#if defined(PNG_cHRM_SUPPORTED)
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_cHRM(png_structp png_ptr, png_infop info_ptr,
+   double *white_x, double *white_y, double *red_x, double *red_y,
+   double *green_x, double *green_y, double *blue_x, double *blue_y)
+{
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_cHRM))
+   {
+      png_debug1(1, "in %s retrieval function\n", "cHRM");
+      if (white_x != NULL)
+         *white_x = (double)info_ptr->x_white;
+      if (white_y != NULL)
+         *white_y = (double)info_ptr->y_white;
+      if (red_x != NULL)
+         *red_x = (double)info_ptr->x_red;
+      if (red_y != NULL)
+         *red_y = (double)info_ptr->y_red;
+      if (green_x != NULL)
+         *green_x = (double)info_ptr->x_green;
+      if (green_y != NULL)
+         *green_y = (double)info_ptr->y_green;
+      if (blue_x != NULL)
+         *blue_x = (double)info_ptr->x_blue;
+      if (blue_y != NULL)
+         *blue_y = (double)info_ptr->y_blue;
+      return (PNG_INFO_cHRM);
+   }
+   return (0);
+}
+#endif
+#ifdef PNG_FIXED_POINT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_cHRM_fixed(png_structp png_ptr, png_infop info_ptr,
+   png_fixed_point *white_x, png_fixed_point *white_y, png_fixed_point *red_x,
+   png_fixed_point *red_y, png_fixed_point *green_x, png_fixed_point *green_y,
+   png_fixed_point *blue_x, png_fixed_point *blue_y)
+{
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_cHRM))
+   {
+      png_debug1(1, "in %s retrieval function\n", "cHRM");
+      if (white_x != NULL)
+         *white_x = info_ptr->int_x_white;
+      if (white_y != NULL)
+         *white_y = info_ptr->int_y_white;
+      if (red_x != NULL)
+         *red_x = info_ptr->int_x_red;
+      if (red_y != NULL)
+         *red_y = info_ptr->int_y_red;
+      if (green_x != NULL)
+         *green_x = info_ptr->int_x_green;
+      if (green_y != NULL)
+         *green_y = info_ptr->int_y_green;
+      if (blue_x != NULL)
+         *blue_x = info_ptr->int_x_blue;
+      if (blue_y != NULL)
+         *blue_y = info_ptr->int_y_blue;
+      return (PNG_INFO_cHRM);
+   }
+   return (0);
+}
+#endif
+#endif
+
+#if defined(PNG_gAMA_SUPPORTED)
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_gAMA(png_structp png_ptr, png_infop info_ptr, double *file_gamma)
+{
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_gAMA)
+      && file_gamma != NULL)
+   {
+      png_debug1(1, "in %s retrieval function\n", "gAMA");
+      *file_gamma = (double)info_ptr->gamma;
+      return (PNG_INFO_gAMA);
+   }
+   return (0);
+}
+#endif
+#ifdef PNG_FIXED_POINT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_gAMA_fixed(png_structp png_ptr, png_infop info_ptr,
+    png_fixed_point *int_file_gamma)
+{
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_gAMA)
+      && int_file_gamma != NULL)
+   {
+      png_debug1(1, "in %s retrieval function\n", "gAMA");
+      *int_file_gamma = info_ptr->int_gamma;
+      return (PNG_INFO_gAMA);
+   }
+   return (0);
+}
+#endif
+#endif
+
+#if defined(PNG_sRGB_SUPPORTED)
+png_uint_32 PNGAPI
+png_get_sRGB(png_structp png_ptr, png_infop info_ptr, int *file_srgb_intent)
+{
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_sRGB)
+      && file_srgb_intent != NULL)
+   {
+      png_debug1(1, "in %s retrieval function\n", "sRGB");
+      *file_srgb_intent = (int)info_ptr->srgb_intent;
+      return (PNG_INFO_sRGB);
+   }
+   return (0);
+}
+#endif
+
+#if defined(PNG_iCCP_SUPPORTED)
+png_uint_32 PNGAPI
+png_get_iCCP(png_structp png_ptr, png_infop info_ptr,
+             png_charpp name, int *compression_type,
+             png_charpp profile, png_uint_32 *proflen)
+{
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_iCCP)
+      && name != NULL && profile != NULL && proflen != NULL)
+   {
+      png_debug1(1, "in %s retrieval function\n", "iCCP");
+      *name = info_ptr->iccp_name;
+      *profile = info_ptr->iccp_profile;
+      /* compression_type is a dummy so the API won't have to change
+         if we introduce multiple compression types later. */
+      *proflen = (int)info_ptr->iccp_proflen;
+      *compression_type = (int)info_ptr->iccp_compression;
+      return (PNG_INFO_iCCP);
+   }
+   return (0);
+}
+#endif
+
+#if defined(PNG_sPLT_SUPPORTED)
+png_uint_32 PNGAPI
+png_get_sPLT(png_structp png_ptr, png_infop info_ptr,
+             png_sPLT_tpp spalettes)
+{
+   if (png_ptr != NULL && info_ptr != NULL && spalettes != NULL)
+   {
+     *spalettes = info_ptr->splt_palettes;
+     return ((png_uint_32)info_ptr->splt_palettes_num);
+   }
+   return (0);
+}
+#endif
+
+#if defined(PNG_hIST_SUPPORTED)
+png_uint_32 PNGAPI
+png_get_hIST(png_structp png_ptr, png_infop info_ptr, png_uint_16p *hist)
+{
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST)
+      && hist != NULL)
+   {
+      png_debug1(1, "in %s retrieval function\n", "hIST");
+      *hist = info_ptr->hist;
+      return (PNG_INFO_hIST);
+   }
+   return (0);
+}
+#endif
+
+png_uint_32 PNGAPI
+png_get_IHDR(png_structp png_ptr, png_infop info_ptr,
+   png_uint_32 *width, png_uint_32 *height, int *bit_depth,
+   int *color_type, int *interlace_type, int *compression_type,
+   int *filter_type)
+
+{
+   if (png_ptr != NULL && info_ptr != NULL && width != NULL && height != NULL &&
+      bit_depth != NULL && color_type != NULL)
+   {
+      png_debug1(1, "in %s retrieval function\n", "IHDR");
+      *width = info_ptr->width;
+      *height = info_ptr->height;
+      *bit_depth = info_ptr->bit_depth;
+      if (info_ptr->bit_depth < 1 || info_ptr->bit_depth > 16)
+        png_error(png_ptr, "Invalid bit depth");
+      *color_type = info_ptr->color_type;
+      if (info_ptr->color_type > 6)
+        png_error(png_ptr, "Invalid color type");
+      if (compression_type != NULL)
+         *compression_type = info_ptr->compression_type;
+      if (filter_type != NULL)
+         *filter_type = info_ptr->filter_type;
+      if (interlace_type != NULL)
+         *interlace_type = info_ptr->interlace_type;
+
+      /* check for potential overflow of rowbytes */
+      if (*width == 0 || *width > PNG_UINT_31_MAX)
+        png_error(png_ptr, "Invalid image width");
+      if (*height == 0 || *height > PNG_UINT_31_MAX)
+        png_error(png_ptr, "Invalid image height");
+      if (info_ptr->width > (PNG_UINT_32_MAX
+                 >> 3)      /* 8-byte RGBA pixels */
+                 - 64       /* bigrowbuf hack */
+                 - 1        /* filter byte */
+                 - 7*8      /* rounding of width to multiple of 8 pixels */
+                 - 8)       /* extra max_pixel_depth pad */
+      {
+         png_warning(png_ptr,
+            "Width too large for libpng to process image data.");
+      }
+      return (1);
+   }
+   return (0);
+}
+
+#if defined(PNG_oFFs_SUPPORTED)
+png_uint_32 PNGAPI
+png_get_oFFs(png_structp png_ptr, png_infop info_ptr,
+   png_int_32 *offset_x, png_int_32 *offset_y, int *unit_type)
+{
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs)
+      && offset_x != NULL && offset_y != NULL && unit_type != NULL)
+   {
+      png_debug1(1, "in %s retrieval function\n", "oFFs");
+      *offset_x = info_ptr->x_offset;
+      *offset_y = info_ptr->y_offset;
+      *unit_type = (int)info_ptr->offset_unit_type;
+      return (PNG_INFO_oFFs);
+   }
+   return (0);
+}
+#endif
+
+#if defined(PNG_pCAL_SUPPORTED)
+png_uint_32 PNGAPI
+png_get_pCAL(png_structp png_ptr, png_infop info_ptr,
+   png_charp *purpose, png_int_32 *X0, png_int_32 *X1, int *type, int *nparams,
+   png_charp *units, png_charpp *params)
+{
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL)
+      && purpose != NULL && X0 != NULL && X1 != NULL && type != NULL &&
+      nparams != NULL && units != NULL && params != NULL)
+   {
+      png_debug1(1, "in %s retrieval function\n", "pCAL");
+      *purpose = info_ptr->pcal_purpose;
+      *X0 = info_ptr->pcal_X0;
+      *X1 = info_ptr->pcal_X1;
+      *type = (int)info_ptr->pcal_type;
+      *nparams = (int)info_ptr->pcal_nparams;
+      *units = info_ptr->pcal_units;
+      *params = info_ptr->pcal_params;
+      return (PNG_INFO_pCAL);
+   }
+   return (0);
+}
+#endif
+
+#if defined(PNG_sCAL_SUPPORTED)
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_sCAL(png_structp png_ptr, png_infop info_ptr,
+             int *unit, double *width, double *height)
+{
+    if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_sCAL))
+    {
+        *unit = info_ptr->scal_unit;
+        *width = info_ptr->scal_pixel_width;
+        *height = info_ptr->scal_pixel_height;
+        return (PNG_INFO_sCAL);
+    }
+    return(0);
+}
+#else
+#ifdef PNG_FIXED_POINT_SUPPORTED
+png_uint_32 PNGAPI
+png_get_sCAL_s(png_structp png_ptr, png_infop info_ptr,
+             int *unit, png_charpp width, png_charpp height)
+{
+    if (png_ptr != NULL && info_ptr != NULL &&
+       (info_ptr->valid & PNG_INFO_sCAL))
+    {
+        *unit = info_ptr->scal_unit;
+        *width = info_ptr->scal_s_width;
+        *height = info_ptr->scal_s_height;
+        return (PNG_INFO_sCAL);
+    }
+    return(0);
+}
+#endif
+#endif
+#endif
+
+#if defined(PNG_pHYs_SUPPORTED)
+png_uint_32 PNGAPI
+png_get_pHYs(png_structp png_ptr, png_infop info_ptr,
+   png_uint_32 *res_x, png_uint_32 *res_y, int *unit_type)
+{
+   png_uint_32 retval = 0;
+
+   if (png_ptr != NULL && info_ptr != NULL &&
+      (info_ptr->valid & PNG_INFO_pHYs))
+   {
+      png_debug1(1, "in %s retrieval function\n", "pHYs");
+      if (res_x != NULL)
+      {
+         *res_x = info_ptr->x_pixels_per_unit;
+         retval |= PNG_INFO_pHYs;
+      }
+      if (res_y != NULL)
+      {
+         *res_y = info_ptr->y_pixels_per_unit;
+         retval |= PNG_INFO_pHYs;
+      }
+      if (unit_type != NULL)
+      {
+         *unit_type = (int)info_ptr->phys_unit_type;
+         retval |= PNG_INFO_pHYs;
+      }
+   }
+   return (retval);
+}
+#endif
+
+png_uint_32 PNGAPI
+png_get_PLTE(png_structp png_ptr, png_infop info_ptr, png_colorp *palette,
+   int *num_palette)
+{
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_PLTE)
+       && palette != NULL)
+   {
+      png_debug1(1, "in %s retrieval function\n", "PLTE");
+      *palette = info_ptr->palette;
+      *num_palette = info_ptr->num_palette;
+      png_debug1(3, "num_palette = %d\n", *num_palette);
+      return (PNG_INFO_PLTE);
+   }
+   return (0);
+}
+
+#if defined(PNG_sBIT_SUPPORTED)
+png_uint_32 PNGAPI
+png_get_sBIT(png_structp png_ptr, png_infop info_ptr, png_color_8p *sig_bit)
+{
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT)
+      && sig_bit != NULL)
+   {
+      png_debug1(1, "in %s retrieval function\n", "sBIT");
+      *sig_bit = &(info_ptr->sig_bit);
+      return (PNG_INFO_sBIT);
+   }
+   return (0);
+}
+#endif
+
+#if defined(PNG_TEXT_SUPPORTED)
+png_uint_32 PNGAPI
+png_get_text(png_structp png_ptr, png_infop info_ptr, png_textp *text_ptr,
+   int *num_text)
+{
+   if (png_ptr != NULL && info_ptr != NULL && info_ptr->num_text > 0)
+   {
+      png_debug1(1, "in %s retrieval function\n",
+         (png_ptr->chunk_name[0] == '\0' ? "text"
+             : (png_const_charp)png_ptr->chunk_name));
+      if (text_ptr != NULL)
+         *text_ptr = info_ptr->text;
+      if (num_text != NULL)
+         *num_text = info_ptr->num_text;
+      return ((png_uint_32)info_ptr->num_text);
+   }
+   if (num_text != NULL)
+     *num_text = 0;
+   return(0);
+}
+#endif
+
+#if defined(PNG_tIME_SUPPORTED)
+png_uint_32 PNGAPI
+png_get_tIME(png_structp png_ptr, png_infop info_ptr, png_timep *mod_time)
+{
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME)
+       && mod_time != NULL)
+   {
+      png_debug1(1, "in %s retrieval function\n", "tIME");
+      *mod_time = &(info_ptr->mod_time);
+      return (PNG_INFO_tIME);
+   }
+   return (0);
+}
+#endif
+
+#if defined(PNG_tRNS_SUPPORTED)
+png_uint_32 PNGAPI
+png_get_tRNS(png_structp png_ptr, png_infop info_ptr,
+   png_bytep *trans, int *num_trans, png_color_16p *trans_values)
+{
+   png_uint_32 retval = 0;
+   if (png_ptr != NULL && info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS))
+   {
+      png_debug1(1, "in %s retrieval function\n", "tRNS");
+      if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      {
+          if (trans != NULL)
+          {
+             *trans = info_ptr->trans;
+             retval |= PNG_INFO_tRNS;
+          }
+          if (trans_values != NULL)
+             *trans_values = &(info_ptr->trans_values);
+      }
+      else /* if (info_ptr->color_type != PNG_COLOR_TYPE_PALETTE) */
+      {
+          if (trans_values != NULL)
+          {
+             *trans_values = &(info_ptr->trans_values);
+             retval |= PNG_INFO_tRNS;
+          }
+          if(trans != NULL)
+             *trans = NULL;
+      }
+      if(num_trans != NULL)
+      {
+         *num_trans = info_ptr->num_trans;
+         retval |= PNG_INFO_tRNS;
+      }
+   }
+   return (retval);
+}
+#endif
+
+#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+png_uint_32 PNGAPI
+png_get_unknown_chunks(png_structp png_ptr, png_infop info_ptr,
+             png_unknown_chunkpp unknowns)
+{
+   if (png_ptr != NULL && info_ptr != NULL && unknowns != NULL)
+   {
+     *unknowns = info_ptr->unknown_chunks;
+     return ((png_uint_32)info_ptr->unknown_chunks_num);
+   }
+   return (0);
+}
+#endif
+
+#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+png_byte PNGAPI
+png_get_rgb_to_gray_status (png_structp png_ptr)
+{
+   return (png_byte)(png_ptr? png_ptr->rgb_to_gray_status : 0);
+}
+#endif
+
+#if defined(PNG_USER_CHUNKS_SUPPORTED)
+png_voidp PNGAPI
+png_get_user_chunk_ptr(png_structp png_ptr)
+{
+   return (png_ptr? png_ptr->user_chunk_ptr : NULL);
+}
+#endif
+
+#ifdef PNG_WRITE_SUPPORTED
+png_uint_32 PNGAPI
+png_get_compression_buffer_size(png_structp png_ptr)
+{
+   return (png_uint_32)(png_ptr? png_ptr->zbuf_size : 0L);
+}
+#endif
+
+#ifdef PNG_ASSEMBLER_CODE_SUPPORTED
+#ifndef PNG_1_0_X
+/* this function was added to libpng 1.2.0 and should exist by default */
+png_uint_32 PNGAPI
+png_get_asm_flags (png_structp png_ptr)
+{
+#ifdef PNG_MMX_CODE_SUPPORTED
+    return (png_uint_32)(png_ptr? png_ptr->asm_flags : 0L);
+#else
+    return (png_ptr? 0L: 0L);
+#endif
+}
+
+/* this function was added to libpng 1.2.0 and should exist by default */
+png_uint_32 PNGAPI
+png_get_asm_flagmask (int flag_select)
+{
+#ifdef PNG_MMX_CODE_SUPPORTED
+    png_uint_32 settable_asm_flags = 0;
+
+    if (flag_select & PNG_SELECT_READ)
+        settable_asm_flags |=
+          PNG_ASM_FLAG_MMX_READ_COMBINE_ROW  |
+          PNG_ASM_FLAG_MMX_READ_INTERLACE    |
+          PNG_ASM_FLAG_MMX_READ_FILTER_SUB   |
+          PNG_ASM_FLAG_MMX_READ_FILTER_UP    |
+          PNG_ASM_FLAG_MMX_READ_FILTER_AVG   |
+          PNG_ASM_FLAG_MMX_READ_FILTER_PAETH ;
+          /* no non-MMX flags yet */
+
+#if 0
+    /* GRR:  no write-flags yet, either, but someday... */
+    if (flag_select & PNG_SELECT_WRITE)
+        settable_asm_flags |=
+          PNG_ASM_FLAG_MMX_WRITE_ [whatever] ;
+#endif /* 0 */
+
+    return settable_asm_flags;  /* _theoretically_ settable capabilities only */
+#else
+    return (0L);
+#endif /* PNG_MMX_CODE_SUPPORTED */
+}
+
+
+    /* GRR:  could add this:   && defined(PNG_MMX_CODE_SUPPORTED) */
+/* this function was added to libpng 1.2.0 */
+png_uint_32 PNGAPI
+png_get_mmx_flagmask (int flag_select, int *compilerID)
+{
+#if defined(PNG_MMX_CODE_SUPPORTED)
+    png_uint_32 settable_mmx_flags = 0;
+
+    if (flag_select & PNG_SELECT_READ)
+        settable_mmx_flags |=
+          PNG_ASM_FLAG_MMX_READ_COMBINE_ROW  |
+          PNG_ASM_FLAG_MMX_READ_INTERLACE    |
+          PNG_ASM_FLAG_MMX_READ_FILTER_SUB   |
+          PNG_ASM_FLAG_MMX_READ_FILTER_UP    |
+          PNG_ASM_FLAG_MMX_READ_FILTER_AVG   |
+          PNG_ASM_FLAG_MMX_READ_FILTER_PAETH ;
+#if 0
+    /* GRR:  no MMX write support yet, but someday... */
+    if (flag_select & PNG_SELECT_WRITE)
+        settable_mmx_flags |=
+          PNG_ASM_FLAG_MMX_WRITE_ [whatever] ;
+#endif /* 0 */
+
+    if (compilerID != NULL) {
+#ifdef PNG_USE_PNGVCRD
+        *compilerID = 1;    /* MSVC */
+#else
+#ifdef PNG_USE_PNGGCCRD
+        *compilerID = 2;    /* gcc/gas */
+#else
+        *compilerID = -1;   /* unknown (i.e., no asm/MMX code compiled) */
+#endif
+#endif
+    }
+
+    return settable_mmx_flags;  /* _theoretically_ settable capabilities only */
+#else
+    return (0L);
+#endif /* ?PNG_MMX_CODE_SUPPORTED */
+}
+
+/* this function was added to libpng 1.2.0 */
+png_byte PNGAPI
+png_get_mmx_bitdepth_threshold (png_structp png_ptr)
+{
+#if defined(PNG_MMX_CODE_SUPPORTED)
+    return (png_byte)(png_ptr? png_ptr->mmx_bitdepth_threshold : 0);
+#else
+    return (png_ptr? 0: 0);
+#endif /* ?PNG_MMX_CODE_SUPPORTED */
+}
+
+/* this function was added to libpng 1.2.0 */
+png_uint_32 PNGAPI
+png_get_mmx_rowbytes_threshold (png_structp png_ptr)
+{
+#if defined(PNG_MMX_CODE_SUPPORTED)
+    return (png_uint_32)(png_ptr? png_ptr->mmx_rowbytes_threshold : 0L);
+#else
+    return (png_ptr? 0L: 0L);
+#endif /* ?PNG_MMX_CODE_SUPPORTED */
+}
+#endif /* ?PNG_1_0_X */
+#endif /* ?PNG_ASSEMBLER_CODE_SUPPORTED */
+
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+/* these functions were added to libpng 1.2.6 */
+png_uint_32 PNGAPI
+png_get_user_width_max (png_structp png_ptr)
+{
+    return (png_ptr? png_ptr->user_width_max : 0);
+}
+png_uint_32 PNGAPI
+png_get_user_height_max (png_structp png_ptr)
+{
+    return (png_ptr? png_ptr->user_height_max : 0);
+}
+#endif /* ?PNG_SET_USER_LIMITS_SUPPORTED */
+ 
+
+#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
diff --git a/distrib/libpng-1.2.19/pngmem.c b/distrib/libpng-1.2.19/pngmem.c
new file mode 100644
index 0000000..248060f
--- /dev/null
+++ b/distrib/libpng-1.2.19/pngmem.c
@@ -0,0 +1,608 @@
+
+/* pngmem.c - stub functions for memory allocation
+ *
+ * Last changed in libpng 1.2.13 November 13, 2006
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1998-2006 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This file provides a location for all memory allocation.  Users who
+ * need special memory handling are expected to supply replacement
+ * functions for png_malloc() and png_free(), and to use
+ * png_create_read_struct_2() and png_create_write_struct_2() to
+ * identify the replacement functions.
+ */
+
+#define PNG_INTERNAL
+#include "png.h"
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+
+/* Borland DOS special memory handler */
+#if defined(__TURBOC__) && !defined(_Windows) && !defined(__FLAT__)
+/* if you change this, be sure to change the one in png.h also */
+
+/* Allocate memory for a png_struct.  The malloc and memset can be replaced
+   by a single call to calloc() if this is thought to improve performance. */
+png_voidp /* PRIVATE */
+png_create_struct(int type)
+{
+#ifdef PNG_USER_MEM_SUPPORTED
+   return (png_create_struct_2(type, png_malloc_ptr_NULL, png_voidp_NULL));
+}
+
+/* Alternate version of png_create_struct, for use with user-defined malloc. */
+png_voidp /* PRIVATE */
+png_create_struct_2(int type, png_malloc_ptr malloc_fn, png_voidp mem_ptr)
+{
+#endif /* PNG_USER_MEM_SUPPORTED */
+   png_size_t size;
+   png_voidp struct_ptr;
+
+   if (type == PNG_STRUCT_INFO)
+     size = png_sizeof(png_info);
+   else if (type == PNG_STRUCT_PNG)
+     size = png_sizeof(png_struct);
+   else
+     return (png_get_copyright(NULL));
+
+#ifdef PNG_USER_MEM_SUPPORTED
+   if(malloc_fn != NULL)
+   {
+      png_struct dummy_struct;
+      png_structp png_ptr = &dummy_struct;
+      png_ptr->mem_ptr=mem_ptr;
+      struct_ptr = (*(malloc_fn))(png_ptr, (png_uint_32)size);
+   }
+   else
+#endif /* PNG_USER_MEM_SUPPORTED */
+      struct_ptr = (png_voidp)farmalloc(size);
+   if (struct_ptr != NULL)
+      png_memset(struct_ptr, 0, size);
+   return (struct_ptr);
+}
+
+/* Free memory allocated by a png_create_struct() call */
+void /* PRIVATE */
+png_destroy_struct(png_voidp struct_ptr)
+{
+#ifdef PNG_USER_MEM_SUPPORTED
+   png_destroy_struct_2(struct_ptr, png_free_ptr_NULL, png_voidp_NULL);
+}
+
+/* Free memory allocated by a png_create_struct() call */
+void /* PRIVATE */
+png_destroy_struct_2(png_voidp struct_ptr, png_free_ptr free_fn,
+    png_voidp mem_ptr)
+{
+#endif
+   if (struct_ptr != NULL)
+   {
+#ifdef PNG_USER_MEM_SUPPORTED
+      if(free_fn != NULL)
+      {
+         png_struct dummy_struct;
+         png_structp png_ptr = &dummy_struct;
+         png_ptr->mem_ptr=mem_ptr;
+         (*(free_fn))(png_ptr, struct_ptr);
+         return;
+      }
+#endif /* PNG_USER_MEM_SUPPORTED */
+      farfree (struct_ptr);
+   }
+}
+
+/* Allocate memory.  For reasonable files, size should never exceed
+ * 64K.  However, zlib may allocate more then 64K if you don't tell
+ * it not to.  See zconf.h and png.h for more information. zlib does
+ * need to allocate exactly 64K, so whatever you call here must
+ * have the ability to do that.
+ *
+ * Borland seems to have a problem in DOS mode for exactly 64K.
+ * It gives you a segment with an offset of 8 (perhaps to store its
+ * memory stuff).  zlib doesn't like this at all, so we have to
+ * detect and deal with it.  This code should not be needed in
+ * Windows or OS/2 modes, and only in 16 bit mode.  This code has
+ * been updated by Alexander Lehmann for version 0.89 to waste less
+ * memory.
+ *
+ * Note that we can't use png_size_t for the "size" declaration,
+ * since on some systems a png_size_t is a 16-bit quantity, and as a
+ * result, we would be truncating potentially larger memory requests
+ * (which should cause a fatal error) and introducing major problems.
+ */
+
+png_voidp PNGAPI
+png_malloc(png_structp png_ptr, png_uint_32 size)
+{
+   png_voidp ret;
+
+   if (png_ptr == NULL || size == 0)
+      return (NULL);
+
+#ifdef PNG_USER_MEM_SUPPORTED
+   if(png_ptr->malloc_fn != NULL)
+       ret = ((png_voidp)(*(png_ptr->malloc_fn))(png_ptr, (png_size_t)size));
+   else
+       ret = (png_malloc_default(png_ptr, size));
+   if (ret == NULL && (png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
+       png_error(png_ptr, "Out of memory!");
+   return (ret);
+}
+
+png_voidp PNGAPI
+png_malloc_default(png_structp png_ptr, png_uint_32 size)
+{
+   png_voidp ret;
+#endif /* PNG_USER_MEM_SUPPORTED */
+
+   if (png_ptr == NULL || size == 0)
+      return (NULL);
+
+#ifdef PNG_MAX_MALLOC_64K
+   if (size > (png_uint_32)65536L)
+   {
+      png_warning(png_ptr, "Cannot Allocate > 64K");
+      ret = NULL;
+   }
+   else
+#endif
+
+   if (size != (size_t)size)
+     ret = NULL;
+   else if (size == (png_uint_32)65536L)
+   {
+      if (png_ptr->offset_table == NULL)
+      {
+         /* try to see if we need to do any of this fancy stuff */
+         ret = farmalloc(size);
+         if (ret == NULL || ((png_size_t)ret & 0xffff))
+         {
+            int num_blocks;
+            png_uint_32 total_size;
+            png_bytep table;
+            int i;
+            png_byte huge * hptr;
+
+            if (ret != NULL)
+            {
+               farfree(ret);
+               ret = NULL;
+            }
+
+            if(png_ptr->zlib_window_bits > 14)
+               num_blocks = (int)(1 << (png_ptr->zlib_window_bits - 14));
+            else
+               num_blocks = 1;
+            if (png_ptr->zlib_mem_level >= 7)
+               num_blocks += (int)(1 << (png_ptr->zlib_mem_level - 7));
+            else
+               num_blocks++;
+
+            total_size = ((png_uint_32)65536L) * (png_uint_32)num_blocks+16;
+
+            table = farmalloc(total_size);
+
+            if (table == NULL)
+            {
+#ifndef PNG_USER_MEM_SUPPORTED
+               if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
+                  png_error(png_ptr, "Out Of Memory."); /* Note "O" and "M" */
+               else
+                  png_warning(png_ptr, "Out Of Memory.");
+#endif
+               return (NULL);
+            }
+
+            if ((png_size_t)table & 0xfff0)
+            {
+#ifndef PNG_USER_MEM_SUPPORTED
+               if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
+                  png_error(png_ptr,
+                    "Farmalloc didn't return normalized pointer");
+               else
+                  png_warning(png_ptr,
+                    "Farmalloc didn't return normalized pointer");
+#endif
+               return (NULL);
+            }
+
+            png_ptr->offset_table = table;
+            png_ptr->offset_table_ptr = farmalloc(num_blocks *
+               png_sizeof (png_bytep));
+
+            if (png_ptr->offset_table_ptr == NULL)
+            {
+#ifndef PNG_USER_MEM_SUPPORTED
+               if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
+                  png_error(png_ptr, "Out Of memory."); /* Note "O" and "M" */
+               else
+                  png_warning(png_ptr, "Out Of memory.");
+#endif
+               return (NULL);
+            }
+
+            hptr = (png_byte huge *)table;
+            if ((png_size_t)hptr & 0xf)
+            {
+               hptr = (png_byte huge *)((long)(hptr) & 0xfffffff0L);
+               hptr = hptr + 16L;  /* "hptr += 16L" fails on Turbo C++ 3.0 */
+            }
+            for (i = 0; i < num_blocks; i++)
+            {
+               png_ptr->offset_table_ptr[i] = (png_bytep)hptr;
+               hptr = hptr + (png_uint_32)65536L;  /* "+=" fails on TC++3.0 */
+            }
+
+            png_ptr->offset_table_number = num_blocks;
+            png_ptr->offset_table_count = 0;
+            png_ptr->offset_table_count_free = 0;
+         }
+      }
+
+      if (png_ptr->offset_table_count >= png_ptr->offset_table_number)
+      {
+#ifndef PNG_USER_MEM_SUPPORTED
+         if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
+            png_error(png_ptr, "Out of Memory."); /* Note "o" and "M" */
+         else
+            png_warning(png_ptr, "Out of Memory.");
+#endif
+         return (NULL);
+      }
+
+      ret = png_ptr->offset_table_ptr[png_ptr->offset_table_count++];
+   }
+   else
+      ret = farmalloc(size);
+
+#ifndef PNG_USER_MEM_SUPPORTED
+   if (ret == NULL)
+   {
+      if ((png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
+         png_error(png_ptr, "Out of memory."); /* Note "o" and "m" */
+      else
+         png_warning(png_ptr, "Out of memory."); /* Note "o" and "m" */
+   }
+#endif
+
+   return (ret);
+}
+
+/* free a pointer allocated by png_malloc().  In the default
+   configuration, png_ptr is not used, but is passed in case it
+   is needed.  If ptr is NULL, return without taking any action. */
+void PNGAPI
+png_free(png_structp png_ptr, png_voidp ptr)
+{
+   if (png_ptr == NULL || ptr == NULL)
+      return;
+
+#ifdef PNG_USER_MEM_SUPPORTED
+   if (png_ptr->free_fn != NULL)
+   {
+      (*(png_ptr->free_fn))(png_ptr, ptr);
+      return;
+   }
+   else png_free_default(png_ptr, ptr);
+}
+
+void PNGAPI
+png_free_default(png_structp png_ptr, png_voidp ptr)
+{
+#endif /* PNG_USER_MEM_SUPPORTED */
+
+   if(png_ptr == NULL) return;
+
+   if (png_ptr->offset_table != NULL)
+   {
+      int i;
+
+      for (i = 0; i < png_ptr->offset_table_count; i++)
+      {
+         if (ptr == png_ptr->offset_table_ptr[i])
+         {
+            ptr = NULL;
+            png_ptr->offset_table_count_free++;
+            break;
+         }
+      }
+      if (png_ptr->offset_table_count_free == png_ptr->offset_table_count)
+      {
+         farfree(png_ptr->offset_table);
+         farfree(png_ptr->offset_table_ptr);
+         png_ptr->offset_table = NULL;
+         png_ptr->offset_table_ptr = NULL;
+      }
+   }
+
+   if (ptr != NULL)
+   {
+      farfree(ptr);
+   }
+}
+
+#else /* Not the Borland DOS special memory handler */
+
+/* Allocate memory for a png_struct or a png_info.  The malloc and
+   memset can be replaced by a single call to calloc() if this is thought
+   to improve performance noticably. */
+png_voidp /* PRIVATE */
+png_create_struct(int type)
+{
+#ifdef PNG_USER_MEM_SUPPORTED
+   return (png_create_struct_2(type, png_malloc_ptr_NULL, png_voidp_NULL));
+}
+
+/* Allocate memory for a png_struct or a png_info.  The malloc and
+   memset can be replaced by a single call to calloc() if this is thought
+   to improve performance noticably. */
+png_voidp /* PRIVATE */
+png_create_struct_2(int type, png_malloc_ptr malloc_fn, png_voidp mem_ptr)
+{
+#endif /* PNG_USER_MEM_SUPPORTED */
+   png_size_t size;
+   png_voidp struct_ptr;
+
+   if (type == PNG_STRUCT_INFO)
+      size = png_sizeof(png_info);
+   else if (type == PNG_STRUCT_PNG)
+      size = png_sizeof(png_struct);
+   else
+      return (NULL);
+
+#ifdef PNG_USER_MEM_SUPPORTED
+   if(malloc_fn != NULL)
+   {
+      png_struct dummy_struct;
+      png_structp png_ptr = &dummy_struct;
+      png_ptr->mem_ptr=mem_ptr;
+      struct_ptr = (*(malloc_fn))(png_ptr, size);
+      if (struct_ptr != NULL)
+         png_memset(struct_ptr, 0, size);
+      return (struct_ptr);
+   }
+#endif /* PNG_USER_MEM_SUPPORTED */
+
+#if defined(__TURBOC__) && !defined(__FLAT__)
+   struct_ptr = (png_voidp)farmalloc(size);
+#else
+# if defined(_MSC_VER) && defined(MAXSEG_64K)
+   struct_ptr = (png_voidp)halloc(size,1);
+# else
+   struct_ptr = (png_voidp)malloc(size);
+# endif
+#endif
+   if (struct_ptr != NULL)
+      png_memset(struct_ptr, 0, size);
+
+   return (struct_ptr);
+}
+
+
+/* Free memory allocated by a png_create_struct() call */
+void /* PRIVATE */
+png_destroy_struct(png_voidp struct_ptr)
+{
+#ifdef PNG_USER_MEM_SUPPORTED
+   png_destroy_struct_2(struct_ptr, png_free_ptr_NULL, png_voidp_NULL);
+}
+
+/* Free memory allocated by a png_create_struct() call */
+void /* PRIVATE */
+png_destroy_struct_2(png_voidp struct_ptr, png_free_ptr free_fn,
+    png_voidp mem_ptr)
+{
+#endif /* PNG_USER_MEM_SUPPORTED */
+   if (struct_ptr != NULL)
+   {
+#ifdef PNG_USER_MEM_SUPPORTED
+      if(free_fn != NULL)
+      {
+         png_struct dummy_struct;
+         png_structp png_ptr = &dummy_struct;
+         png_ptr->mem_ptr=mem_ptr;
+         (*(free_fn))(png_ptr, struct_ptr);
+         return;
+      }
+#endif /* PNG_USER_MEM_SUPPORTED */
+#if defined(__TURBOC__) && !defined(__FLAT__)
+      farfree(struct_ptr);
+#else
+# if defined(_MSC_VER) && defined(MAXSEG_64K)
+      hfree(struct_ptr);
+# else
+      free(struct_ptr);
+# endif
+#endif
+   }
+}
+
+/* Allocate memory.  For reasonable files, size should never exceed
+   64K.  However, zlib may allocate more then 64K if you don't tell
+   it not to.  See zconf.h and png.h for more information.  zlib does
+   need to allocate exactly 64K, so whatever you call here must
+   have the ability to do that. */
+
+png_voidp PNGAPI
+png_malloc(png_structp png_ptr, png_uint_32 size)
+{
+   png_voidp ret;
+
+#ifdef PNG_USER_MEM_SUPPORTED
+   if (png_ptr == NULL || size == 0)
+      return (NULL);
+
+   if(png_ptr->malloc_fn != NULL)
+       ret = ((png_voidp)(*(png_ptr->malloc_fn))(png_ptr, (png_size_t)size));
+   else
+       ret = (png_malloc_default(png_ptr, size));
+   if (ret == NULL && (png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
+       png_error(png_ptr, "Out of Memory!");
+   return (ret);
+}
+
+png_voidp PNGAPI
+png_malloc_default(png_structp png_ptr, png_uint_32 size)
+{
+   png_voidp ret;
+#endif /* PNG_USER_MEM_SUPPORTED */
+
+   if (png_ptr == NULL || size == 0)
+      return (NULL);
+
+#ifdef PNG_MAX_MALLOC_64K
+   if (size > (png_uint_32)65536L)
+   {
+#ifndef PNG_USER_MEM_SUPPORTED
+      if(png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
+         png_error(png_ptr, "Cannot Allocate > 64K");
+      else
+#endif
+         return NULL;
+   }
+#endif
+
+ /* Check for overflow */
+#if defined(__TURBOC__) && !defined(__FLAT__)
+ if (size != (unsigned long)size)
+   ret = NULL;
+ else
+   ret = farmalloc(size);
+#else
+# if defined(_MSC_VER) && defined(MAXSEG_64K)
+ if (size != (unsigned long)size)
+   ret = NULL;
+ else
+   ret = halloc(size, 1);
+# else
+ if (size != (size_t)size)
+   ret = NULL;
+ else
+   ret = malloc((size_t)size);
+# endif
+#endif
+
+#ifndef PNG_USER_MEM_SUPPORTED
+   if (ret == NULL && (png_ptr->flags&PNG_FLAG_MALLOC_NULL_MEM_OK) == 0)
+      png_error(png_ptr, "Out of Memory");
+#endif
+
+   return (ret);
+}
+
+/* Free a pointer allocated by png_malloc().  If ptr is NULL, return
+   without taking any action. */
+void PNGAPI
+png_free(png_structp png_ptr, png_voidp ptr)
+{
+   if (png_ptr == NULL || ptr == NULL)
+      return;
+
+#ifdef PNG_USER_MEM_SUPPORTED
+   if (png_ptr->free_fn != NULL)
+   {
+      (*(png_ptr->free_fn))(png_ptr, ptr);
+      return;
+   }
+   else png_free_default(png_ptr, ptr);
+}
+void PNGAPI
+png_free_default(png_structp png_ptr, png_voidp ptr)
+{
+   if (png_ptr == NULL || ptr == NULL)
+      return;
+
+#endif /* PNG_USER_MEM_SUPPORTED */
+
+#if defined(__TURBOC__) && !defined(__FLAT__)
+   farfree(ptr);
+#else
+# if defined(_MSC_VER) && defined(MAXSEG_64K)
+   hfree(ptr);
+# else
+   free(ptr);
+# endif
+#endif
+}
+
+#endif /* Not Borland DOS special memory handler */
+
+#if defined(PNG_1_0_X)
+#  define png_malloc_warn png_malloc
+#else
+/* This function was added at libpng version 1.2.3.  The png_malloc_warn()
+ * function will set up png_malloc() to issue a png_warning and return NULL
+ * instead of issuing a png_error, if it fails to allocate the requested
+ * memory.
+ */
+png_voidp PNGAPI
+png_malloc_warn(png_structp png_ptr, png_uint_32 size)
+{
+   png_voidp ptr;
+   png_uint_32 save_flags;
+   if(png_ptr == NULL) return (NULL);
+
+   save_flags=png_ptr->flags;
+   png_ptr->flags|=PNG_FLAG_MALLOC_NULL_MEM_OK;
+   ptr = (png_voidp)png_malloc((png_structp)png_ptr, size);
+   png_ptr->flags=save_flags;
+   return(ptr);
+}
+#endif
+
+png_voidp PNGAPI
+png_memcpy_check (png_structp png_ptr, png_voidp s1, png_voidp s2,
+   png_uint_32 length)
+{
+   png_size_t size;
+
+   size = (png_size_t)length;
+   if ((png_uint_32)size != length)
+      png_error(png_ptr,"Overflow in png_memcpy_check.");
+
+   return(png_memcpy (s1, s2, size));
+}
+
+png_voidp PNGAPI
+png_memset_check (png_structp png_ptr, png_voidp s1, int value,
+   png_uint_32 length)
+{
+   png_size_t size;
+
+   size = (png_size_t)length;
+   if ((png_uint_32)size != length)
+      png_error(png_ptr,"Overflow in png_memset_check.");
+
+   return (png_memset (s1, value, size));
+
+}
+
+#ifdef PNG_USER_MEM_SUPPORTED
+/* This function is called when the application wants to use another method
+ * of allocating and freeing memory.
+ */
+void PNGAPI
+png_set_mem_fn(png_structp png_ptr, png_voidp mem_ptr, png_malloc_ptr
+  malloc_fn, png_free_ptr free_fn)
+{
+   if(png_ptr != NULL) {
+   png_ptr->mem_ptr = mem_ptr;
+   png_ptr->malloc_fn = malloc_fn;
+   png_ptr->free_fn = free_fn;
+   }
+}
+
+/* This function returns a pointer to the mem_ptr associated with the user
+ * functions.  The application should free any memory associated with this
+ * pointer before png_write_destroy and png_read_destroy are called.
+ */
+png_voidp PNGAPI
+png_get_mem_ptr(png_structp png_ptr)
+{
+   if(png_ptr == NULL) return (NULL);
+   return ((png_voidp)png_ptr->mem_ptr);
+}
+#endif /* PNG_USER_MEM_SUPPORTED */
+#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
diff --git a/distrib/libpng-1.2.19/pngpread.c b/distrib/libpng-1.2.19/pngpread.c
new file mode 100644
index 0000000..7d29e98
--- /dev/null
+++ b/distrib/libpng-1.2.19/pngpread.c
@@ -0,0 +1,1585 @@
+
+/* pngpread.c - read a png file in push mode
+ *
+ * Last changed in libpng 1.2.19 August 18, 2007
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1998-2007 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ */
+
+#define PNG_INTERNAL
+#include "png.h"
+
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+
+/* push model modes */
+#define PNG_READ_SIG_MODE   0
+#define PNG_READ_CHUNK_MODE 1
+#define PNG_READ_IDAT_MODE  2
+#define PNG_SKIP_MODE       3
+#define PNG_READ_tEXt_MODE  4
+#define PNG_READ_zTXt_MODE  5
+#define PNG_READ_DONE_MODE  6
+#define PNG_READ_iTXt_MODE  7
+#define PNG_ERROR_MODE      8
+
+void PNGAPI
+png_process_data(png_structp png_ptr, png_infop info_ptr,
+   png_bytep buffer, png_size_t buffer_size)
+{
+   if(png_ptr == NULL) return;
+   png_push_restore_buffer(png_ptr, buffer, buffer_size);
+
+   while (png_ptr->buffer_size)
+   {
+      png_process_some_data(png_ptr, info_ptr);
+   }
+}
+
+/* What we do with the incoming data depends on what we were previously
+ * doing before we ran out of data...
+ */
+void /* PRIVATE */
+png_process_some_data(png_structp png_ptr, png_infop info_ptr)
+{
+   if(png_ptr == NULL) return;
+   switch (png_ptr->process_mode)
+   {
+      case PNG_READ_SIG_MODE:
+      {
+         png_push_read_sig(png_ptr, info_ptr);
+         break;
+      }
+      case PNG_READ_CHUNK_MODE:
+      {
+         png_push_read_chunk(png_ptr, info_ptr);
+         break;
+      }
+      case PNG_READ_IDAT_MODE:
+      {
+         png_push_read_IDAT(png_ptr);
+         break;
+      }
+#if defined(PNG_READ_tEXt_SUPPORTED)
+      case PNG_READ_tEXt_MODE:
+      {
+         png_push_read_tEXt(png_ptr, info_ptr);
+         break;
+      }
+#endif
+#if defined(PNG_READ_zTXt_SUPPORTED)
+      case PNG_READ_zTXt_MODE:
+      {
+         png_push_read_zTXt(png_ptr, info_ptr);
+         break;
+      }
+#endif
+#if defined(PNG_READ_iTXt_SUPPORTED)
+      case PNG_READ_iTXt_MODE:
+      {
+         png_push_read_iTXt(png_ptr, info_ptr);
+         break;
+      }
+#endif
+      case PNG_SKIP_MODE:
+      {
+         png_push_crc_finish(png_ptr);
+         break;
+      }
+      default:
+      {
+         png_ptr->buffer_size = 0;
+         break;
+      }
+   }
+}
+
+/* Read any remaining signature bytes from the stream and compare them with
+ * the correct PNG signature.  It is possible that this routine is called
+ * with bytes already read from the signature, either because they have been
+ * checked by the calling application, or because of multiple calls to this
+ * routine.
+ */
+void /* PRIVATE */
+png_push_read_sig(png_structp png_ptr, png_infop info_ptr)
+{
+   png_size_t num_checked = png_ptr->sig_bytes,
+             num_to_check = 8 - num_checked;
+
+   if (png_ptr->buffer_size < num_to_check)
+   {
+      num_to_check = png_ptr->buffer_size;
+   }
+
+   png_push_fill_buffer(png_ptr, &(info_ptr->signature[num_checked]),
+      num_to_check);
+   png_ptr->sig_bytes = (png_byte)(png_ptr->sig_bytes+num_to_check);
+
+   if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
+   {
+      if (num_checked < 4 &&
+          png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
+         png_error(png_ptr, "Not a PNG file");
+      else
+         png_error(png_ptr, "PNG file corrupted by ASCII conversion");
+   }
+   else
+   {
+      if (png_ptr->sig_bytes >= 8)
+      {
+         png_ptr->process_mode = PNG_READ_CHUNK_MODE;
+      }
+   }
+}
+
+void /* PRIVATE */
+png_push_read_chunk(png_structp png_ptr, png_infop info_ptr)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+      PNG_CONST PNG_IHDR;
+      PNG_CONST PNG_IDAT;
+      PNG_CONST PNG_IEND;
+      PNG_CONST PNG_PLTE;
+#if defined(PNG_READ_bKGD_SUPPORTED)
+      PNG_CONST PNG_bKGD;
+#endif
+#if defined(PNG_READ_cHRM_SUPPORTED)
+      PNG_CONST PNG_cHRM;
+#endif
+#if defined(PNG_READ_gAMA_SUPPORTED)
+      PNG_CONST PNG_gAMA;
+#endif
+#if defined(PNG_READ_hIST_SUPPORTED)
+      PNG_CONST PNG_hIST;
+#endif
+#if defined(PNG_READ_iCCP_SUPPORTED)
+      PNG_CONST PNG_iCCP;
+#endif
+#if defined(PNG_READ_iTXt_SUPPORTED)
+      PNG_CONST PNG_iTXt;
+#endif
+#if defined(PNG_READ_oFFs_SUPPORTED)
+      PNG_CONST PNG_oFFs;
+#endif
+#if defined(PNG_READ_pCAL_SUPPORTED)
+      PNG_CONST PNG_pCAL;
+#endif
+#if defined(PNG_READ_pHYs_SUPPORTED)
+      PNG_CONST PNG_pHYs;
+#endif
+#if defined(PNG_READ_sBIT_SUPPORTED)
+      PNG_CONST PNG_sBIT;
+#endif
+#if defined(PNG_READ_sCAL_SUPPORTED)
+      PNG_CONST PNG_sCAL;
+#endif
+#if defined(PNG_READ_sRGB_SUPPORTED)
+      PNG_CONST PNG_sRGB;
+#endif
+#if defined(PNG_READ_sPLT_SUPPORTED)
+      PNG_CONST PNG_sPLT;
+#endif
+#if defined(PNG_READ_tEXt_SUPPORTED)
+      PNG_CONST PNG_tEXt;
+#endif
+#if defined(PNG_READ_tIME_SUPPORTED)
+      PNG_CONST PNG_tIME;
+#endif
+#if defined(PNG_READ_tRNS_SUPPORTED)
+      PNG_CONST PNG_tRNS;
+#endif
+#if defined(PNG_READ_zTXt_SUPPORTED)
+      PNG_CONST PNG_zTXt;
+#endif
+#endif /* PNG_USE_LOCAL_ARRAYS */
+   /* First we make sure we have enough data for the 4 byte chunk name
+    * and the 4 byte chunk length before proceeding with decoding the
+    * chunk data.  To fully decode each of these chunks, we also make
+    * sure we have enough data in the buffer for the 4 byte CRC at the
+    * end of every chunk (except IDAT, which is handled separately).
+    */
+   if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
+   {
+      png_byte chunk_length[4];
+
+      if (png_ptr->buffer_size < 8)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
+      png_push_fill_buffer(png_ptr, chunk_length, 4);
+      png_ptr->push_length = png_get_uint_31(png_ptr,chunk_length);
+      png_reset_crc(png_ptr);
+      png_crc_read(png_ptr, png_ptr->chunk_name, 4);
+      png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
+   }
+
+   if (!png_memcmp(png_ptr->chunk_name, (png_bytep)png_IDAT, 4))
+     if(png_ptr->mode & PNG_AFTER_IDAT)
+        png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
+
+   if (!png_memcmp(png_ptr->chunk_name, png_IHDR, 4))
+   {
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+      png_handle_IHDR(png_ptr, info_ptr, png_ptr->push_length);
+   }
+   else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
+   {
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+      png_handle_IEND(png_ptr, info_ptr, png_ptr->push_length);
+
+      png_ptr->process_mode = PNG_READ_DONE_MODE;
+      png_push_have_end(png_ptr, info_ptr);
+   }
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+   else if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name))
+   {
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+      if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
+         png_ptr->mode |= PNG_HAVE_IDAT;
+      png_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
+      if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
+         png_ptr->mode |= PNG_HAVE_PLTE;
+      else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
+      {
+         if (!(png_ptr->mode & PNG_HAVE_IHDR))
+            png_error(png_ptr, "Missing IHDR before IDAT");
+         else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
+                  !(png_ptr->mode & PNG_HAVE_PLTE))
+            png_error(png_ptr, "Missing PLTE before IDAT");
+      }
+   }
+#endif
+   else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
+   {
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+      png_handle_PLTE(png_ptr, info_ptr, png_ptr->push_length);
+   }
+   else if (!png_memcmp(png_ptr->chunk_name, (png_bytep)png_IDAT, 4))
+   {
+      /* If we reach an IDAT chunk, this means we have read all of the
+       * header chunks, and we can start reading the image (or if this
+       * is called after the image has been read - we have an error).
+       */
+     if (!(png_ptr->mode & PNG_HAVE_IHDR))
+       png_error(png_ptr, "Missing IHDR before IDAT");
+     else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
+         !(png_ptr->mode & PNG_HAVE_PLTE))
+       png_error(png_ptr, "Missing PLTE before IDAT");
+
+      if (png_ptr->mode & PNG_HAVE_IDAT)
+      {
+         if (!(png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
+           if (png_ptr->push_length == 0)
+              return;
+
+         if (png_ptr->mode & PNG_AFTER_IDAT)
+            png_error(png_ptr, "Too many IDAT's found");
+      }
+
+      png_ptr->idat_size = png_ptr->push_length;
+      png_ptr->mode |= PNG_HAVE_IDAT;
+      png_ptr->process_mode = PNG_READ_IDAT_MODE;
+      png_push_have_info(png_ptr, info_ptr);
+      png_ptr->zstream.avail_out = (uInt)png_ptr->irowbytes;
+      png_ptr->zstream.next_out = png_ptr->row_buf;
+      return;
+   }
+#if defined(PNG_READ_gAMA_SUPPORTED)
+   else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4))
+   {
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+      png_handle_gAMA(png_ptr, info_ptr, png_ptr->push_length);
+   }
+#endif
+#if defined(PNG_READ_sBIT_SUPPORTED)
+   else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))
+   {
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+      png_handle_sBIT(png_ptr, info_ptr, png_ptr->push_length);
+   }
+#endif
+#if defined(PNG_READ_cHRM_SUPPORTED)
+   else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))
+   {
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+      png_handle_cHRM(png_ptr, info_ptr, png_ptr->push_length);
+   }
+#endif
+#if defined(PNG_READ_sRGB_SUPPORTED)
+   else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
+   {
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+      png_handle_sRGB(png_ptr, info_ptr, png_ptr->push_length);
+   }
+#endif
+#if defined(PNG_READ_iCCP_SUPPORTED)
+   else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
+   {
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+      png_handle_iCCP(png_ptr, info_ptr, png_ptr->push_length);
+   }
+#endif
+#if defined(PNG_READ_sPLT_SUPPORTED)
+   else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
+   {
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+      png_handle_sPLT(png_ptr, info_ptr, png_ptr->push_length);
+   }
+#endif
+#if defined(PNG_READ_tRNS_SUPPORTED)
+   else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
+   {
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+      png_handle_tRNS(png_ptr, info_ptr, png_ptr->push_length);
+   }
+#endif
+#if defined(PNG_READ_bKGD_SUPPORTED)
+   else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))
+   {
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+      png_handle_bKGD(png_ptr, info_ptr, png_ptr->push_length);
+   }
+#endif
+#if defined(PNG_READ_hIST_SUPPORTED)
+   else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))
+   {
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+      png_handle_hIST(png_ptr, info_ptr, png_ptr->push_length);
+   }
+#endif
+#if defined(PNG_READ_pHYs_SUPPORTED)
+   else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))
+   {
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+      png_handle_pHYs(png_ptr, info_ptr, png_ptr->push_length);
+   }
+#endif
+#if defined(PNG_READ_oFFs_SUPPORTED)
+   else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))
+   {
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+      png_handle_oFFs(png_ptr, info_ptr, png_ptr->push_length);
+   }
+#endif
+#if defined(PNG_READ_pCAL_SUPPORTED)
+   else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))
+   {
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+      png_handle_pCAL(png_ptr, info_ptr, png_ptr->push_length);
+   }
+#endif
+#if defined(PNG_READ_sCAL_SUPPORTED)
+   else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
+   {
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+      png_handle_sCAL(png_ptr, info_ptr, png_ptr->push_length);
+   }
+#endif
+#if defined(PNG_READ_tIME_SUPPORTED)
+   else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))
+   {
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+      png_handle_tIME(png_ptr, info_ptr, png_ptr->push_length);
+   }
+#endif
+#if defined(PNG_READ_tEXt_SUPPORTED)
+   else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4))
+   {
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+      png_push_handle_tEXt(png_ptr, info_ptr, png_ptr->push_length);
+   }
+#endif
+#if defined(PNG_READ_zTXt_SUPPORTED)
+   else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))
+   {
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+      png_push_handle_zTXt(png_ptr, info_ptr, png_ptr->push_length);
+   }
+#endif
+#if defined(PNG_READ_iTXt_SUPPORTED)
+   else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))
+   {
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+      png_push_handle_iTXt(png_ptr, info_ptr, png_ptr->push_length);
+   }
+#endif
+   else
+   {
+      if (png_ptr->push_length + 4 > png_ptr->buffer_size)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+      png_push_handle_unknown(png_ptr, info_ptr, png_ptr->push_length);
+   }
+
+   png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
+}
+
+void /* PRIVATE */
+png_push_crc_skip(png_structp png_ptr, png_uint_32 skip)
+{
+   png_ptr->process_mode = PNG_SKIP_MODE;
+   png_ptr->skip_length = skip;
+}
+
+void /* PRIVATE */
+png_push_crc_finish(png_structp png_ptr)
+{
+   if (png_ptr->skip_length && png_ptr->save_buffer_size)
+   {
+      png_size_t save_size;
+
+      if (png_ptr->skip_length < (png_uint_32)png_ptr->save_buffer_size)
+         save_size = (png_size_t)png_ptr->skip_length;
+      else
+         save_size = png_ptr->save_buffer_size;
+
+      png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
+
+      png_ptr->skip_length -= save_size;
+      png_ptr->buffer_size -= save_size;
+      png_ptr->save_buffer_size -= save_size;
+      png_ptr->save_buffer_ptr += save_size;
+   }
+   if (png_ptr->skip_length && png_ptr->current_buffer_size)
+   {
+      png_size_t save_size;
+
+      if (png_ptr->skip_length < (png_uint_32)png_ptr->current_buffer_size)
+         save_size = (png_size_t)png_ptr->skip_length;
+      else
+         save_size = png_ptr->current_buffer_size;
+
+      png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
+
+      png_ptr->skip_length -= save_size;
+      png_ptr->buffer_size -= save_size;
+      png_ptr->current_buffer_size -= save_size;
+      png_ptr->current_buffer_ptr += save_size;
+   }
+   if (!png_ptr->skip_length)
+   {
+      if (png_ptr->buffer_size < 4)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
+      png_crc_finish(png_ptr, 0);
+      png_ptr->process_mode = PNG_READ_CHUNK_MODE;
+   }
+}
+
+void PNGAPI
+png_push_fill_buffer(png_structp png_ptr, png_bytep buffer, png_size_t length)
+{
+   png_bytep ptr;
+
+   if(png_ptr == NULL) return;
+   ptr = buffer;
+   if (png_ptr->save_buffer_size)
+   {
+      png_size_t save_size;
+
+      if (length < png_ptr->save_buffer_size)
+         save_size = length;
+      else
+         save_size = png_ptr->save_buffer_size;
+
+      png_memcpy(ptr, png_ptr->save_buffer_ptr, save_size);
+      length -= save_size;
+      ptr += save_size;
+      png_ptr->buffer_size -= save_size;
+      png_ptr->save_buffer_size -= save_size;
+      png_ptr->save_buffer_ptr += save_size;
+   }
+   if (length && png_ptr->current_buffer_size)
+   {
+      png_size_t save_size;
+
+      if (length < png_ptr->current_buffer_size)
+         save_size = length;
+      else
+         save_size = png_ptr->current_buffer_size;
+
+      png_memcpy(ptr, png_ptr->current_buffer_ptr, save_size);
+      png_ptr->buffer_size -= save_size;
+      png_ptr->current_buffer_size -= save_size;
+      png_ptr->current_buffer_ptr += save_size;
+   }
+}
+
+void /* PRIVATE */
+png_push_save_buffer(png_structp png_ptr)
+{
+   if (png_ptr->save_buffer_size)
+   {
+      if (png_ptr->save_buffer_ptr != png_ptr->save_buffer)
+      {
+         png_size_t i,istop;
+         png_bytep sp;
+         png_bytep dp;
+
+         istop = png_ptr->save_buffer_size;
+         for (i = 0, sp = png_ptr->save_buffer_ptr, dp = png_ptr->save_buffer;
+            i < istop; i++, sp++, dp++)
+         {
+            *dp = *sp;
+         }
+      }
+   }
+   if (png_ptr->save_buffer_size + png_ptr->current_buffer_size >
+      png_ptr->save_buffer_max)
+   {
+      png_size_t new_max;
+      png_bytep old_buffer;
+
+      if (png_ptr->save_buffer_size > PNG_SIZE_MAX -
+         (png_ptr->current_buffer_size + 256))
+      {
+        png_error(png_ptr, "Potential overflow of save_buffer");
+      }
+      new_max = png_ptr->save_buffer_size + png_ptr->current_buffer_size + 256;
+      old_buffer = png_ptr->save_buffer;
+      png_ptr->save_buffer = (png_bytep)png_malloc(png_ptr,
+         (png_uint_32)new_max);
+      png_memcpy(png_ptr->save_buffer, old_buffer, png_ptr->save_buffer_size);
+      png_free(png_ptr, old_buffer);
+      png_ptr->save_buffer_max = new_max;
+   }
+   if (png_ptr->current_buffer_size)
+   {
+      png_memcpy(png_ptr->save_buffer + png_ptr->save_buffer_size,
+         png_ptr->current_buffer_ptr, png_ptr->current_buffer_size);
+      png_ptr->save_buffer_size += png_ptr->current_buffer_size;
+      png_ptr->current_buffer_size = 0;
+   }
+   png_ptr->save_buffer_ptr = png_ptr->save_buffer;
+   png_ptr->buffer_size = 0;
+}
+
+void /* PRIVATE */
+png_push_restore_buffer(png_structp png_ptr, png_bytep buffer,
+   png_size_t buffer_length)
+{
+   png_ptr->current_buffer = buffer;
+   png_ptr->current_buffer_size = buffer_length;
+   png_ptr->buffer_size = buffer_length + png_ptr->save_buffer_size;
+   png_ptr->current_buffer_ptr = png_ptr->current_buffer;
+}
+
+void /* PRIVATE */
+png_push_read_IDAT(png_structp png_ptr)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_CONST PNG_IDAT;
+#endif
+   if (!(png_ptr->mode & PNG_HAVE_CHUNK_HEADER))
+   {
+      png_byte chunk_length[4];
+
+      if (png_ptr->buffer_size < 8)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
+      png_push_fill_buffer(png_ptr, chunk_length, 4);
+      png_ptr->push_length = png_get_uint_31(png_ptr,chunk_length);
+      png_reset_crc(png_ptr);
+      png_crc_read(png_ptr, png_ptr->chunk_name, 4);
+      png_ptr->mode |= PNG_HAVE_CHUNK_HEADER;
+
+      if (png_memcmp(png_ptr->chunk_name, (png_bytep)png_IDAT, 4))
+      {
+         png_ptr->process_mode = PNG_READ_CHUNK_MODE;
+         if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
+            png_error(png_ptr, "Not enough compressed data");
+         return;
+      }
+
+      png_ptr->idat_size = png_ptr->push_length;
+   }
+   if (png_ptr->idat_size && png_ptr->save_buffer_size)
+   {
+      png_size_t save_size;
+
+      if (png_ptr->idat_size < (png_uint_32)png_ptr->save_buffer_size)
+      {
+         save_size = (png_size_t)png_ptr->idat_size;
+         /* check for overflow */
+         if((png_uint_32)save_size != png_ptr->idat_size)
+            png_error(png_ptr, "save_size overflowed in pngpread");
+      }
+      else
+         save_size = png_ptr->save_buffer_size;
+
+      png_calculate_crc(png_ptr, png_ptr->save_buffer_ptr, save_size);
+      if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
+         png_process_IDAT_data(png_ptr, png_ptr->save_buffer_ptr, save_size);
+      png_ptr->idat_size -= save_size;
+      png_ptr->buffer_size -= save_size;
+      png_ptr->save_buffer_size -= save_size;
+      png_ptr->save_buffer_ptr += save_size;
+   }
+   if (png_ptr->idat_size && png_ptr->current_buffer_size)
+   {
+      png_size_t save_size;
+
+      if (png_ptr->idat_size < (png_uint_32)png_ptr->current_buffer_size)
+      {
+         save_size = (png_size_t)png_ptr->idat_size;
+         /* check for overflow */
+         if((png_uint_32)save_size != png_ptr->idat_size)
+            png_error(png_ptr, "save_size overflowed in pngpread");
+      }
+      else
+         save_size = png_ptr->current_buffer_size;
+
+      png_calculate_crc(png_ptr, png_ptr->current_buffer_ptr, save_size);
+      if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
+        png_process_IDAT_data(png_ptr, png_ptr->current_buffer_ptr, save_size);
+
+      png_ptr->idat_size -= save_size;
+      png_ptr->buffer_size -= save_size;
+      png_ptr->current_buffer_size -= save_size;
+      png_ptr->current_buffer_ptr += save_size;
+   }
+   if (!png_ptr->idat_size)
+   {
+      if (png_ptr->buffer_size < 4)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
+      png_crc_finish(png_ptr, 0);
+      png_ptr->mode &= ~PNG_HAVE_CHUNK_HEADER;
+      png_ptr->mode |= PNG_AFTER_IDAT;
+   }
+}
+
+void /* PRIVATE */
+png_process_IDAT_data(png_structp png_ptr, png_bytep buffer,
+   png_size_t buffer_length)
+{
+   int ret;
+
+   if ((png_ptr->flags & PNG_FLAG_ZLIB_FINISHED) && buffer_length)
+      png_error(png_ptr, "Extra compression data");
+
+   png_ptr->zstream.next_in = buffer;
+   png_ptr->zstream.avail_in = (uInt)buffer_length;
+   for(;;)
+   {
+      ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
+      if (ret != Z_OK)
+      {
+         if (ret == Z_STREAM_END)
+         {
+            if (png_ptr->zstream.avail_in)
+               png_error(png_ptr, "Extra compressed data");
+            if (!(png_ptr->zstream.avail_out))
+            {
+               png_push_process_row(png_ptr);
+            }
+
+            png_ptr->mode |= PNG_AFTER_IDAT;
+            png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
+            break;
+         }
+         else if (ret == Z_BUF_ERROR)
+            break;
+         else
+            png_error(png_ptr, "Decompression Error");
+      }
+      if (!(png_ptr->zstream.avail_out))
+      {
+         if ((
+#if defined(PNG_READ_INTERLACING_SUPPORTED)
+             png_ptr->interlaced && png_ptr->pass > 6) ||
+             (!png_ptr->interlaced &&
+#endif
+             png_ptr->row_number == png_ptr->num_rows))
+         {
+           if (png_ptr->zstream.avail_in)
+             png_warning(png_ptr, "Too much data in IDAT chunks");
+           png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
+           break;
+         }
+         png_push_process_row(png_ptr);
+         png_ptr->zstream.avail_out = (uInt)png_ptr->irowbytes;
+         png_ptr->zstream.next_out = png_ptr->row_buf;
+      }
+      else
+         break;
+   }
+}
+
+void /* PRIVATE */
+png_push_process_row(png_structp png_ptr)
+{
+   png_ptr->row_info.color_type = png_ptr->color_type;
+   png_ptr->row_info.width = png_ptr->iwidth;
+   png_ptr->row_info.channels = png_ptr->channels;
+   png_ptr->row_info.bit_depth = png_ptr->bit_depth;
+   png_ptr->row_info.pixel_depth = png_ptr->pixel_depth;
+
+   png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
+       png_ptr->row_info.width);
+
+   png_read_filter_row(png_ptr, &(png_ptr->row_info),
+      png_ptr->row_buf + 1, png_ptr->prev_row + 1,
+      (int)(png_ptr->row_buf[0]));
+
+   png_memcpy_check(png_ptr, png_ptr->prev_row, png_ptr->row_buf,
+      png_ptr->rowbytes + 1);
+
+   if (png_ptr->transformations || (png_ptr->flags&PNG_FLAG_STRIP_ALPHA))
+      png_do_read_transformations(png_ptr);
+
+#if defined(PNG_READ_INTERLACING_SUPPORTED)
+   /* blow up interlaced rows to full size */
+   if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
+   {
+      if (png_ptr->pass < 6)
+/*       old interface (pre-1.0.9):
+         png_do_read_interlace(&(png_ptr->row_info),
+            png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);
+ */
+         png_do_read_interlace(png_ptr);
+
+    switch (png_ptr->pass)
+    {
+         case 0:
+         {
+            int i;
+            for (i = 0; i < 8 && png_ptr->pass == 0; i++)
+            {
+               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+               png_read_push_finish_row(png_ptr); /* updates png_ptr->pass */
+            }
+            if (png_ptr->pass == 2) /* pass 1 might be empty */
+            {
+               for (i = 0; i < 4 && png_ptr->pass == 2; i++)
+               {
+                  png_push_have_row(png_ptr, png_bytep_NULL);
+                  png_read_push_finish_row(png_ptr);
+               }
+            }
+            if (png_ptr->pass == 4 && png_ptr->height <= 4)
+            {
+               for (i = 0; i < 2 && png_ptr->pass == 4; i++)
+               {
+                  png_push_have_row(png_ptr, png_bytep_NULL);
+                  png_read_push_finish_row(png_ptr);
+               }
+            }
+            if (png_ptr->pass == 6 && png_ptr->height <= 4)
+            {
+                png_push_have_row(png_ptr, png_bytep_NULL);
+                png_read_push_finish_row(png_ptr);
+            }
+            break;
+         }
+         case 1:
+         {
+            int i;
+            for (i = 0; i < 8 && png_ptr->pass == 1; i++)
+            {
+               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+               png_read_push_finish_row(png_ptr);
+            }
+            if (png_ptr->pass == 2) /* skip top 4 generated rows */
+            {
+               for (i = 0; i < 4 && png_ptr->pass == 2; i++)
+               {
+                  png_push_have_row(png_ptr, png_bytep_NULL);
+                  png_read_push_finish_row(png_ptr);
+               }
+            }
+            break;
+         }
+         case 2:
+         {
+            int i;
+            for (i = 0; i < 4 && png_ptr->pass == 2; i++)
+            {
+               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+               png_read_push_finish_row(png_ptr);
+            }
+            for (i = 0; i < 4 && png_ptr->pass == 2; i++)
+            {
+               png_push_have_row(png_ptr, png_bytep_NULL);
+               png_read_push_finish_row(png_ptr);
+            }
+            if (png_ptr->pass == 4) /* pass 3 might be empty */
+            {
+               for (i = 0; i < 2 && png_ptr->pass == 4; i++)
+               {
+                  png_push_have_row(png_ptr, png_bytep_NULL);
+                  png_read_push_finish_row(png_ptr);
+               }
+            }
+            break;
+         }
+         case 3:
+         {
+            int i;
+            for (i = 0; i < 4 && png_ptr->pass == 3; i++)
+            {
+               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+               png_read_push_finish_row(png_ptr);
+            }
+            if (png_ptr->pass == 4) /* skip top two generated rows */
+            {
+               for (i = 0; i < 2 && png_ptr->pass == 4; i++)
+               {
+                  png_push_have_row(png_ptr, png_bytep_NULL);
+                  png_read_push_finish_row(png_ptr);
+               }
+            }
+            break;
+         }
+         case 4:
+         {
+            int i;
+            for (i = 0; i < 2 && png_ptr->pass == 4; i++)
+            {
+               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+               png_read_push_finish_row(png_ptr);
+            }
+            for (i = 0; i < 2 && png_ptr->pass == 4; i++)
+            {
+               png_push_have_row(png_ptr, png_bytep_NULL);
+               png_read_push_finish_row(png_ptr);
+            }
+            if (png_ptr->pass == 6) /* pass 5 might be empty */
+            {
+               png_push_have_row(png_ptr, png_bytep_NULL);
+               png_read_push_finish_row(png_ptr);
+            }
+            break;
+         }
+         case 5:
+         {
+            int i;
+            for (i = 0; i < 2 && png_ptr->pass == 5; i++)
+            {
+               png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+               png_read_push_finish_row(png_ptr);
+            }
+            if (png_ptr->pass == 6) /* skip top generated row */
+            {
+               png_push_have_row(png_ptr, png_bytep_NULL);
+               png_read_push_finish_row(png_ptr);
+            }
+            break;
+         }
+         case 6:
+         {
+            png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+            png_read_push_finish_row(png_ptr);
+            if (png_ptr->pass != 6)
+               break;
+            png_push_have_row(png_ptr, png_bytep_NULL);
+            png_read_push_finish_row(png_ptr);
+         }
+      }
+   }
+   else
+#endif
+   {
+      png_push_have_row(png_ptr, png_ptr->row_buf + 1);
+      png_read_push_finish_row(png_ptr);
+   }
+}
+
+void /* PRIVATE */
+png_read_push_finish_row(png_structp png_ptr)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+   /* start of interlace block */
+   PNG_CONST int FARDATA png_pass_start[] = {0, 4, 0, 2, 0, 1, 0};
+
+   /* offset to next interlace block */
+   PNG_CONST int FARDATA png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1};
+
+   /* start of interlace block in the y direction */
+   PNG_CONST int FARDATA png_pass_ystart[] = {0, 0, 4, 0, 2, 0, 1};
+
+   /* offset to next interlace block in the y direction */
+   PNG_CONST int FARDATA png_pass_yinc[] = {8, 8, 8, 4, 4, 2, 2};
+
+   /* Width of interlace block.  This is not currently used - if you need
+    * it, uncomment it here and in png.h
+   PNG_CONST int FARDATA png_pass_width[] = {8, 4, 4, 2, 2, 1, 1};
+   */
+
+   /* Height of interlace block.  This is not currently used - if you need
+    * it, uncomment it here and in png.h
+   PNG_CONST int FARDATA png_pass_height[] = {8, 8, 4, 4, 2, 2, 1};
+   */
+#endif
+
+   png_ptr->row_number++;
+   if (png_ptr->row_number < png_ptr->num_rows)
+      return;
+
+   if (png_ptr->interlaced)
+   {
+      png_ptr->row_number = 0;
+      png_memset_check(png_ptr, png_ptr->prev_row, 0,
+         png_ptr->rowbytes + 1);
+      do
+      {
+         png_ptr->pass++;
+         if ((png_ptr->pass == 1 && png_ptr->width < 5) ||
+             (png_ptr->pass == 3 && png_ptr->width < 3) ||
+             (png_ptr->pass == 5 && png_ptr->width < 2))
+           png_ptr->pass++;
+
+         if (png_ptr->pass > 7)
+            png_ptr->pass--;
+         if (png_ptr->pass >= 7)
+            break;
+
+         png_ptr->iwidth = (png_ptr->width +
+            png_pass_inc[png_ptr->pass] - 1 -
+            png_pass_start[png_ptr->pass]) /
+            png_pass_inc[png_ptr->pass];
+
+         png_ptr->irowbytes = PNG_ROWBYTES(png_ptr->pixel_depth,
+            png_ptr->iwidth) + 1;
+
+         if (png_ptr->transformations & PNG_INTERLACE)
+            break;
+
+         png_ptr->num_rows = (png_ptr->height +
+            png_pass_yinc[png_ptr->pass] - 1 -
+            png_pass_ystart[png_ptr->pass]) /
+            png_pass_yinc[png_ptr->pass];
+
+      } while (png_ptr->iwidth == 0 || png_ptr->num_rows == 0);
+   }
+}
+
+#if defined(PNG_READ_tEXt_SUPPORTED)
+void /* PRIVATE */
+png_push_handle_tEXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
+   length)
+{
+   if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
+      {
+         png_error(png_ptr, "Out of place tEXt");
+         info_ptr = info_ptr; /* to quiet some compiler warnings */
+      }
+
+#ifdef PNG_MAX_MALLOC_64K
+   png_ptr->skip_length = 0;  /* This may not be necessary */
+
+   if (length > (png_uint_32)65535L) /* Can't hold entire string in memory */
+   {
+      png_warning(png_ptr, "tEXt chunk too large to fit in memory");
+      png_ptr->skip_length = length - (png_uint_32)65535L;
+      length = (png_uint_32)65535L;
+   }
+#endif
+
+   png_ptr->current_text = (png_charp)png_malloc(png_ptr,
+         (png_uint_32)(length+1));
+   png_ptr->current_text[length] = '\0';
+   png_ptr->current_text_ptr = png_ptr->current_text;
+   png_ptr->current_text_size = (png_size_t)length;
+   png_ptr->current_text_left = (png_size_t)length;
+   png_ptr->process_mode = PNG_READ_tEXt_MODE;
+}
+
+void /* PRIVATE */
+png_push_read_tEXt(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr->buffer_size && png_ptr->current_text_left)
+   {
+      png_size_t text_size;
+
+      if (png_ptr->buffer_size < png_ptr->current_text_left)
+         text_size = png_ptr->buffer_size;
+      else
+         text_size = png_ptr->current_text_left;
+      png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
+      png_ptr->current_text_left -= text_size;
+      png_ptr->current_text_ptr += text_size;
+   }
+   if (!(png_ptr->current_text_left))
+   {
+      png_textp text_ptr;
+      png_charp text;
+      png_charp key;
+      int ret;
+
+      if (png_ptr->buffer_size < 4)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
+      png_push_crc_finish(png_ptr);
+
+#if defined(PNG_MAX_MALLOC_64K)
+      if (png_ptr->skip_length)
+         return;
+#endif
+
+      key = png_ptr->current_text;
+
+      for (text = key; *text; text++)
+         /* empty loop */ ;
+
+      if (text != key + png_ptr->current_text_size)
+         text++;
+
+      text_ptr = (png_textp)png_malloc(png_ptr,
+         (png_uint_32)png_sizeof(png_text));
+      text_ptr->compression = PNG_TEXT_COMPRESSION_NONE;
+      text_ptr->key = key;
+#ifdef PNG_iTXt_SUPPORTED
+      text_ptr->lang = NULL;
+      text_ptr->lang_key = NULL;
+#endif
+      text_ptr->text = text;
+
+      ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
+
+      png_free(png_ptr, key);
+      png_free(png_ptr, text_ptr);
+      png_ptr->current_text = NULL;
+
+      if (ret)
+        png_warning(png_ptr, "Insufficient memory to store text chunk.");
+   }
+}
+#endif
+
+#if defined(PNG_READ_zTXt_SUPPORTED)
+void /* PRIVATE */
+png_push_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
+   length)
+{
+   if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
+      {
+         png_error(png_ptr, "Out of place zTXt");
+         info_ptr = info_ptr; /* to quiet some compiler warnings */
+      }
+
+#ifdef PNG_MAX_MALLOC_64K
+   /* We can't handle zTXt chunks > 64K, since we don't have enough space
+    * to be able to store the uncompressed data.  Actually, the threshold
+    * is probably around 32K, but it isn't as definite as 64K is.
+    */
+   if (length > (png_uint_32)65535L)
+   {
+      png_warning(png_ptr, "zTXt chunk too large to fit in memory");
+      png_push_crc_skip(png_ptr, length);
+      return;
+   }
+#endif
+
+   png_ptr->current_text = (png_charp)png_malloc(png_ptr,
+       (png_uint_32)(length+1));
+   png_ptr->current_text[length] = '\0';
+   png_ptr->current_text_ptr = png_ptr->current_text;
+   png_ptr->current_text_size = (png_size_t)length;
+   png_ptr->current_text_left = (png_size_t)length;
+   png_ptr->process_mode = PNG_READ_zTXt_MODE;
+}
+
+void /* PRIVATE */
+png_push_read_zTXt(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr->buffer_size && png_ptr->current_text_left)
+   {
+      png_size_t text_size;
+
+      if (png_ptr->buffer_size < (png_uint_32)png_ptr->current_text_left)
+         text_size = png_ptr->buffer_size;
+      else
+         text_size = png_ptr->current_text_left;
+      png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
+      png_ptr->current_text_left -= text_size;
+      png_ptr->current_text_ptr += text_size;
+   }
+   if (!(png_ptr->current_text_left))
+   {
+      png_textp text_ptr;
+      png_charp text;
+      png_charp key;
+      int ret;
+      png_size_t text_size, key_size;
+
+      if (png_ptr->buffer_size < 4)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
+      png_push_crc_finish(png_ptr);
+
+      key = png_ptr->current_text;
+
+      for (text = key; *text; text++)
+         /* empty loop */ ;
+
+      /* zTXt can't have zero text */
+      if (text == key + png_ptr->current_text_size)
+      {
+         png_ptr->current_text = NULL;
+         png_free(png_ptr, key);
+         return;
+      }
+
+      text++;
+
+      if (*text != PNG_TEXT_COMPRESSION_zTXt) /* check compression byte */
+      {
+         png_ptr->current_text = NULL;
+         png_free(png_ptr, key);
+         return;
+      }
+
+      text++;
+
+      png_ptr->zstream.next_in = (png_bytep )text;
+      png_ptr->zstream.avail_in = (uInt)(png_ptr->current_text_size -
+         (text - key));
+      png_ptr->zstream.next_out = png_ptr->zbuf;
+      png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+
+      key_size = text - key;
+      text_size = 0;
+      text = NULL;
+      ret = Z_STREAM_END;
+
+      while (png_ptr->zstream.avail_in)
+      {
+         ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
+         if (ret != Z_OK && ret != Z_STREAM_END)
+         {
+            inflateReset(&png_ptr->zstream);
+            png_ptr->zstream.avail_in = 0;
+            png_ptr->current_text = NULL;
+            png_free(png_ptr, key);
+            png_free(png_ptr, text);
+            return;
+         }
+         if (!(png_ptr->zstream.avail_out) || ret == Z_STREAM_END)
+         {
+            if (text == NULL)
+            {
+               text = (png_charp)png_malloc(png_ptr,
+                  (png_uint_32)(png_ptr->zbuf_size - png_ptr->zstream.avail_out
+                     + key_size + 1));
+               png_memcpy(text + key_size, png_ptr->zbuf,
+                  png_ptr->zbuf_size - png_ptr->zstream.avail_out);
+               png_memcpy(text, key, key_size);
+               text_size = key_size + png_ptr->zbuf_size -
+                  png_ptr->zstream.avail_out;
+               *(text + text_size) = '\0';
+            }
+            else
+            {
+               png_charp tmp;
+
+               tmp = text;
+               text = (png_charp)png_malloc(png_ptr, text_size +
+                  (png_uint_32)(png_ptr->zbuf_size - png_ptr->zstream.avail_out
+                   + 1));
+               png_memcpy(text, tmp, text_size);
+               png_free(png_ptr, tmp);
+               png_memcpy(text + text_size, png_ptr->zbuf,
+                  png_ptr->zbuf_size - png_ptr->zstream.avail_out);
+               text_size += png_ptr->zbuf_size - png_ptr->zstream.avail_out;
+               *(text + text_size) = '\0';
+            }
+            if (ret != Z_STREAM_END)
+            {
+               png_ptr->zstream.next_out = png_ptr->zbuf;
+               png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+            }
+         }
+         else
+         {
+            break;
+         }
+
+         if (ret == Z_STREAM_END)
+            break;
+      }
+
+      inflateReset(&png_ptr->zstream);
+      png_ptr->zstream.avail_in = 0;
+
+      if (ret != Z_STREAM_END)
+      {
+         png_ptr->current_text = NULL;
+         png_free(png_ptr, key);
+         png_free(png_ptr, text);
+         return;
+      }
+
+      png_ptr->current_text = NULL;
+      png_free(png_ptr, key);
+      key = text;
+      text += key_size;
+
+      text_ptr = (png_textp)png_malloc(png_ptr,
+          (png_uint_32)png_sizeof(png_text));
+      text_ptr->compression = PNG_TEXT_COMPRESSION_zTXt;
+      text_ptr->key = key;
+#ifdef PNG_iTXt_SUPPORTED
+      text_ptr->lang = NULL;
+      text_ptr->lang_key = NULL;
+#endif
+      text_ptr->text = text;
+
+      ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
+
+      png_free(png_ptr, key);
+      png_free(png_ptr, text_ptr);
+
+      if (ret)
+        png_warning(png_ptr, "Insufficient memory to store text chunk.");
+   }
+}
+#endif
+
+#if defined(PNG_READ_iTXt_SUPPORTED)
+void /* PRIVATE */
+png_push_handle_iTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32
+   length)
+{
+   if (!(png_ptr->mode & PNG_HAVE_IHDR) || (png_ptr->mode & PNG_HAVE_IEND))
+      {
+         png_error(png_ptr, "Out of place iTXt");
+         info_ptr = info_ptr; /* to quiet some compiler warnings */
+      }
+
+#ifdef PNG_MAX_MALLOC_64K
+   png_ptr->skip_length = 0;  /* This may not be necessary */
+
+   if (length > (png_uint_32)65535L) /* Can't hold entire string in memory */
+   {
+      png_warning(png_ptr, "iTXt chunk too large to fit in memory");
+      png_ptr->skip_length = length - (png_uint_32)65535L;
+      length = (png_uint_32)65535L;
+   }
+#endif
+
+   png_ptr->current_text = (png_charp)png_malloc(png_ptr,
+         (png_uint_32)(length+1));
+   png_ptr->current_text[length] = '\0';
+   png_ptr->current_text_ptr = png_ptr->current_text;
+   png_ptr->current_text_size = (png_size_t)length;
+   png_ptr->current_text_left = (png_size_t)length;
+   png_ptr->process_mode = PNG_READ_iTXt_MODE;
+}
+
+void /* PRIVATE */
+png_push_read_iTXt(png_structp png_ptr, png_infop info_ptr)
+{
+
+   if (png_ptr->buffer_size && png_ptr->current_text_left)
+   {
+      png_size_t text_size;
+
+      if (png_ptr->buffer_size < png_ptr->current_text_left)
+         text_size = png_ptr->buffer_size;
+      else
+         text_size = png_ptr->current_text_left;
+      png_crc_read(png_ptr, (png_bytep)png_ptr->current_text_ptr, text_size);
+      png_ptr->current_text_left -= text_size;
+      png_ptr->current_text_ptr += text_size;
+   }
+   if (!(png_ptr->current_text_left))
+   {
+      png_textp text_ptr;
+      png_charp key;
+      int comp_flag;
+      png_charp lang;
+      png_charp lang_key;
+      png_charp text;
+      int ret;
+
+      if (png_ptr->buffer_size < 4)
+      {
+         png_push_save_buffer(png_ptr);
+         return;
+      }
+
+      png_push_crc_finish(png_ptr);
+
+#if defined(PNG_MAX_MALLOC_64K)
+      if (png_ptr->skip_length)
+         return;
+#endif
+
+      key = png_ptr->current_text;
+
+      for (lang = key; *lang; lang++)
+         /* empty loop */ ;
+
+      if (lang != key + png_ptr->current_text_size)
+         lang++;
+
+      comp_flag = *lang++;
+      lang++;     /* skip comp_type, always zero */
+
+      for (lang_key = lang; *lang_key; lang_key++)
+         /* empty loop */ ;
+      lang_key++;        /* skip NUL separator */
+
+      for (text = lang_key; *text; text++)
+         /* empty loop */ ;
+
+      if (text != key + png_ptr->current_text_size)
+         text++;
+
+      text_ptr = (png_textp)png_malloc(png_ptr,
+         (png_uint_32)png_sizeof(png_text));
+      text_ptr->compression = comp_flag + 2;
+      text_ptr->key = key;
+      text_ptr->lang = lang;
+      text_ptr->lang_key = lang_key;
+      text_ptr->text = text;
+      text_ptr->text_length = 0;
+      text_ptr->itxt_length = png_strlen(text);
+
+      ret = png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
+
+      png_ptr->current_text = NULL;
+
+      png_free(png_ptr, text_ptr);
+      if (ret)
+        png_warning(png_ptr, "Insufficient memory to store iTXt chunk.");
+   }
+}
+#endif
+
+/* This function is called when we haven't found a handler for this
+ * chunk.  If there isn't a problem with the chunk itself (ie a bad chunk
+ * name or a critical chunk), the chunk is (currently) silently ignored.
+ */
+void /* PRIVATE */
+png_push_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32
+   length)
+{
+   png_uint_32 skip=0;
+   png_check_chunk_name(png_ptr, png_ptr->chunk_name);
+
+   if (!(png_ptr->chunk_name[0] & 0x20))
+   {
+#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
+      if(png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
+           PNG_HANDLE_CHUNK_ALWAYS
+#if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
+           && png_ptr->read_user_chunk_fn == NULL
+#endif
+         )
+#endif
+         png_chunk_error(png_ptr, "unknown critical chunk");
+
+      info_ptr = info_ptr; /* to quiet some compiler warnings */
+   }
+
+#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
+   if (png_ptr->flags & PNG_FLAG_KEEP_UNKNOWN_CHUNKS)
+   {
+#ifdef PNG_MAX_MALLOC_64K
+       if (length > (png_uint_32)65535L)
+       {
+           png_warning(png_ptr, "unknown chunk too large to fit in memory");
+           skip = length - (png_uint_32)65535L;
+           length = (png_uint_32)65535L;
+       }
+#endif
+       png_strncpy((png_charp)png_ptr->unknown_chunk.name,
+	 (png_charp)png_ptr->chunk_name,
+         png_sizeof((png_charp)png_ptr->chunk_name));
+       png_ptr->unknown_chunk.data = (png_bytep)png_malloc(png_ptr, length);
+       png_ptr->unknown_chunk.size = (png_size_t)length;
+       png_crc_read(png_ptr, (png_bytep)png_ptr->unknown_chunk.data, length);
+#if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
+       if(png_ptr->read_user_chunk_fn != NULL)
+       {
+          /* callback to user unknown chunk handler */
+          int ret;
+          ret = (*(png_ptr->read_user_chunk_fn))
+            (png_ptr, &png_ptr->unknown_chunk);
+          if (ret < 0)
+             png_chunk_error(png_ptr, "error in user chunk");
+          if (ret == 0)
+          {
+             if (!(png_ptr->chunk_name[0] & 0x20))
+                if(png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
+                     PNG_HANDLE_CHUNK_ALWAYS)
+                   png_chunk_error(png_ptr, "unknown critical chunk");
+                png_set_unknown_chunks(png_ptr, info_ptr,
+                   &png_ptr->unknown_chunk, 1);
+          }
+       }
+#else
+       png_set_unknown_chunks(png_ptr, info_ptr, &png_ptr->unknown_chunk, 1);
+#endif
+       png_free(png_ptr, png_ptr->unknown_chunk.data);
+       png_ptr->unknown_chunk.data = NULL;
+   }
+   else
+#endif
+      skip=length;
+   png_push_crc_skip(png_ptr, skip);
+}
+
+void /* PRIVATE */
+png_push_have_info(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr->info_fn != NULL)
+      (*(png_ptr->info_fn))(png_ptr, info_ptr);
+}
+
+void /* PRIVATE */
+png_push_have_end(png_structp png_ptr, png_infop info_ptr)
+{
+   if (png_ptr->end_fn != NULL)
+      (*(png_ptr->end_fn))(png_ptr, info_ptr);
+}
+
+void /* PRIVATE */
+png_push_have_row(png_structp png_ptr, png_bytep row)
+{
+   if (png_ptr->row_fn != NULL)
+      (*(png_ptr->row_fn))(png_ptr, row, png_ptr->row_number,
+         (int)png_ptr->pass);
+}
+
+void PNGAPI
+png_progressive_combine_row (png_structp png_ptr,
+   png_bytep old_row, png_bytep new_row)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_CONST int FARDATA png_pass_dsp_mask[7] =
+      {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff};
+#endif
+   if(png_ptr == NULL) return;
+   if (new_row != NULL)    /* new_row must == png_ptr->row_buf here. */
+      png_combine_row(png_ptr, old_row, png_pass_dsp_mask[png_ptr->pass]);
+}
+
+void PNGAPI
+png_set_progressive_read_fn(png_structp png_ptr, png_voidp progressive_ptr,
+   png_progressive_info_ptr info_fn, png_progressive_row_ptr row_fn,
+   png_progressive_end_ptr end_fn)
+{
+   if(png_ptr == NULL) return;
+   png_ptr->info_fn = info_fn;
+   png_ptr->row_fn = row_fn;
+   png_ptr->end_fn = end_fn;
+
+   png_set_read_fn(png_ptr, progressive_ptr, png_push_fill_buffer);
+}
+
+png_voidp PNGAPI
+png_get_progressive_ptr(png_structp png_ptr)
+{
+   if(png_ptr == NULL) return (NULL);
+   return png_ptr->io_ptr;
+}
+#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
diff --git a/distrib/libpng-1.2.19/pngread.c b/distrib/libpng-1.2.19/pngread.c
new file mode 100644
index 0000000..2e561e8
--- /dev/null
+++ b/distrib/libpng-1.2.19/pngread.c
@@ -0,0 +1,1478 @@
+
+/* pngread.c - read a PNG file
+ *
+ * Last changed in libpng 1.2.19 August 18, 2007
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1998-2007 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This file contains routines that an application calls directly to
+ * read a PNG file or stream.
+ */
+
+#define PNG_INTERNAL
+#include "png.h"
+
+#if defined(PNG_READ_SUPPORTED)
+
+/* Create a PNG structure for reading, and allocate any memory needed. */
+png_structp PNGAPI
+png_create_read_struct(png_const_charp user_png_ver, png_voidp error_ptr,
+   png_error_ptr error_fn, png_error_ptr warn_fn)
+{
+
+#ifdef PNG_USER_MEM_SUPPORTED
+   return (png_create_read_struct_2(user_png_ver, error_ptr, error_fn,
+      warn_fn, png_voidp_NULL, png_malloc_ptr_NULL, png_free_ptr_NULL));
+}
+
+/* Alternate create PNG structure for reading, and allocate any memory needed. */
+png_structp PNGAPI
+png_create_read_struct_2(png_const_charp user_png_ver, png_voidp error_ptr,
+   png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
+   png_malloc_ptr malloc_fn, png_free_ptr free_fn)
+{
+#endif /* PNG_USER_MEM_SUPPORTED */
+
+   png_structp png_ptr;
+
+#ifdef PNG_SETJMP_SUPPORTED
+#ifdef USE_FAR_KEYWORD
+   jmp_buf jmpbuf;
+#endif
+#endif
+
+   int i;
+
+   png_debug(1, "in png_create_read_struct\n");
+#ifdef PNG_USER_MEM_SUPPORTED
+   png_ptr = (png_structp)png_create_struct_2(PNG_STRUCT_PNG,
+      (png_malloc_ptr)malloc_fn, (png_voidp)mem_ptr);
+#else
+   png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
+#endif
+   if (png_ptr == NULL)
+      return (NULL);
+
+#if !defined(PNG_1_0_X)
+#ifdef PNG_MMX_CODE_SUPPORTED
+   png_init_mmx_flags(png_ptr);   /* 1.2.0 addition */
+#endif
+#endif /* PNG_1_0_X */
+
+   /* added at libpng-1.2.6 */
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+   png_ptr->user_width_max=PNG_USER_WIDTH_MAX;
+   png_ptr->user_height_max=PNG_USER_HEIGHT_MAX;
+#endif
+
+#ifdef PNG_SETJMP_SUPPORTED
+#ifdef USE_FAR_KEYWORD
+   if (setjmp(jmpbuf))
+#else
+   if (setjmp(png_ptr->jmpbuf))
+#endif
+   {
+      png_free(png_ptr, png_ptr->zbuf);
+      png_ptr->zbuf=NULL;
+#ifdef PNG_USER_MEM_SUPPORTED
+      png_destroy_struct_2((png_voidp)png_ptr,
+         (png_free_ptr)free_fn, (png_voidp)mem_ptr);
+#else
+      png_destroy_struct((png_voidp)png_ptr);
+#endif
+      return (NULL);
+   }
+#ifdef USE_FAR_KEYWORD
+   png_memcpy(png_ptr->jmpbuf,jmpbuf,png_sizeof(jmp_buf));
+#endif
+#endif
+
+#ifdef PNG_USER_MEM_SUPPORTED
+   png_set_mem_fn(png_ptr, mem_ptr, malloc_fn, free_fn);
+#endif
+
+   png_set_error_fn(png_ptr, error_ptr, error_fn, warn_fn);
+
+   i=0;
+   do
+   {
+     if(user_png_ver[i] != png_libpng_ver[i])
+        png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
+   } while (png_libpng_ver[i++]);
+
+   if (png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH)
+   {
+     /* Libpng 0.90 and later are binary incompatible with libpng 0.89, so
+      * we must recompile any applications that use any older library version.
+      * For versions after libpng 1.0, we will be compatible, so we need
+      * only check the first digit.
+      */
+     if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] ||
+         (user_png_ver[0] == '1' && user_png_ver[2] != png_libpng_ver[2]) ||
+         (user_png_ver[0] == '0' && user_png_ver[2] < '9'))
+     {
+#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
+        char msg[80];
+        if (user_png_ver)
+        {
+          png_snprintf(msg, 80,
+             "Application was compiled with png.h from libpng-%.20s",
+             user_png_ver);
+          png_warning(png_ptr, msg);
+        }
+        png_snprintf(msg, 80,
+             "Application  is  running with png.c from libpng-%.20s",
+           png_libpng_ver);
+        png_warning(png_ptr, msg);
+#endif
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+        png_ptr->flags=0;
+#endif
+        png_error(png_ptr,
+           "Incompatible libpng version in application and library");
+     }
+   }
+
+   /* initialize zbuf - compression buffer */
+   png_ptr->zbuf_size = PNG_ZBUF_SIZE;
+   png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
+     (png_uint_32)png_ptr->zbuf_size);
+   png_ptr->zstream.zalloc = png_zalloc;
+   png_ptr->zstream.zfree = png_zfree;
+   png_ptr->zstream.opaque = (voidpf)png_ptr;
+
+   switch (inflateInit(&png_ptr->zstream))
+   {
+     case Z_OK: /* Do nothing */ break;
+     case Z_MEM_ERROR:
+     case Z_STREAM_ERROR: png_error(png_ptr, "zlib memory error"); break;
+     case Z_VERSION_ERROR: png_error(png_ptr, "zlib version error"); break;
+     default: png_error(png_ptr, "Unknown zlib error");
+   }
+
+   png_ptr->zstream.next_out = png_ptr->zbuf;
+   png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+
+   png_set_read_fn(png_ptr, png_voidp_NULL, png_rw_ptr_NULL);
+
+#ifdef PNG_SETJMP_SUPPORTED
+/* Applications that neglect to set up their own setjmp() and then encounter
+   a png_error() will longjmp here.  Since the jmpbuf is then meaningless we
+   abort instead of returning. */
+#ifdef USE_FAR_KEYWORD
+   if (setjmp(jmpbuf))
+      PNG_ABORT();
+   png_memcpy(png_ptr->jmpbuf,jmpbuf,png_sizeof(jmp_buf));
+#else
+   if (setjmp(png_ptr->jmpbuf))
+      PNG_ABORT();
+#endif
+#endif
+   return (png_ptr);
+}
+
+#if defined(PNG_1_0_X) || defined(PNG_1_2_X)
+/* Initialize PNG structure for reading, and allocate any memory needed.
+   This interface is deprecated in favour of the png_create_read_struct(),
+   and it will disappear as of libpng-1.3.0. */
+#undef png_read_init
+void PNGAPI
+png_read_init(png_structp png_ptr)
+{
+   /* We only come here via pre-1.0.7-compiled applications */
+   png_read_init_2(png_ptr, "1.0.6 or earlier", 0, 0);
+}
+
+void PNGAPI
+png_read_init_2(png_structp png_ptr, png_const_charp user_png_ver,
+   png_size_t png_struct_size, png_size_t png_info_size)
+{
+   /* We only come here via pre-1.0.12-compiled applications */
+   if(png_ptr == NULL) return;
+#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
+   if(png_sizeof(png_struct) > png_struct_size ||
+      png_sizeof(png_info) > png_info_size)
+   {
+      char msg[80];
+      png_ptr->warning_fn=NULL;
+      if (user_png_ver)
+      {
+        png_snprintf(msg, 80,
+           "Application was compiled with png.h from libpng-%.20s",
+           user_png_ver);
+        png_warning(png_ptr, msg);
+      }
+      png_snprintf(msg, 80,
+         "Application  is  running with png.c from libpng-%.20s",
+         png_libpng_ver);
+      png_warning(png_ptr, msg);
+   }
+#endif
+   if(png_sizeof(png_struct) > png_struct_size)
+     {
+       png_ptr->error_fn=NULL;
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+       png_ptr->flags=0;
+#endif
+       png_error(png_ptr,
+       "The png struct allocated by the application for reading is too small.");
+     }
+   if(png_sizeof(png_info) > png_info_size)
+     {
+       png_ptr->error_fn=NULL;
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+       png_ptr->flags=0;
+#endif
+       png_error(png_ptr,
+         "The info struct allocated by application for reading is too small.");
+     }
+   png_read_init_3(&png_ptr, user_png_ver, png_struct_size);
+}
+#endif /* PNG_1_0_X || PNG_1_2_X */
+
+void PNGAPI
+png_read_init_3(png_structpp ptr_ptr, png_const_charp user_png_ver,
+   png_size_t png_struct_size)
+{
+#ifdef PNG_SETJMP_SUPPORTED
+   jmp_buf tmp_jmp;  /* to save current jump buffer */
+#endif
+
+   int i=0;
+
+   png_structp png_ptr=*ptr_ptr;
+
+   if(png_ptr == NULL) return;
+
+   do
+   {
+     if(user_png_ver[i] != png_libpng_ver[i])
+     {
+#ifdef PNG_LEGACY_SUPPORTED
+       png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
+#else
+       png_ptr->warning_fn=NULL;
+       png_warning(png_ptr,
+        "Application uses deprecated png_read_init() and should be recompiled.");
+       break;
+#endif
+     }
+   } while (png_libpng_ver[i++]);
+
+   png_debug(1, "in png_read_init_3\n");
+
+#ifdef PNG_SETJMP_SUPPORTED
+   /* save jump buffer and error functions */
+   png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof (jmp_buf));
+#endif
+
+   if(png_sizeof(png_struct) > png_struct_size)
+     {
+       png_destroy_struct(png_ptr);
+       *ptr_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
+       png_ptr = *ptr_ptr;
+     }
+
+   /* reset all variables to 0 */
+   png_memset(png_ptr, 0, png_sizeof (png_struct));
+
+#ifdef PNG_SETJMP_SUPPORTED
+   /* restore jump buffer */
+   png_memcpy(png_ptr->jmpbuf, tmp_jmp, png_sizeof (jmp_buf));
+#endif
+
+   /* added at libpng-1.2.6 */
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+   png_ptr->user_width_max=PNG_USER_WIDTH_MAX;
+   png_ptr->user_height_max=PNG_USER_HEIGHT_MAX;
+#endif
+
+   /* initialize zbuf - compression buffer */
+   png_ptr->zbuf_size = PNG_ZBUF_SIZE;
+   png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
+     (png_uint_32)png_ptr->zbuf_size);
+   png_ptr->zstream.zalloc = png_zalloc;
+   png_ptr->zstream.zfree = png_zfree;
+   png_ptr->zstream.opaque = (voidpf)png_ptr;
+
+   switch (inflateInit(&png_ptr->zstream))
+   {
+     case Z_OK: /* Do nothing */ break;
+     case Z_MEM_ERROR:
+     case Z_STREAM_ERROR: png_error(png_ptr, "zlib memory"); break;
+     case Z_VERSION_ERROR: png_error(png_ptr, "zlib version"); break;
+     default: png_error(png_ptr, "Unknown zlib error");
+   }
+
+   png_ptr->zstream.next_out = png_ptr->zbuf;
+   png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+
+   png_set_read_fn(png_ptr, png_voidp_NULL, png_rw_ptr_NULL);
+}
+
+#ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
+/* Read the information before the actual image data.  This has been
+ * changed in v0.90 to allow reading a file that already has the magic
+ * bytes read from the stream.  You can tell libpng how many bytes have
+ * been read from the beginning of the stream (up to the maximum of 8)
+ * via png_set_sig_bytes(), and we will only check the remaining bytes
+ * here.  The application can then have access to the signature bytes we
+ * read if it is determined that this isn't a valid PNG file.
+ */
+void PNGAPI
+png_read_info(png_structp png_ptr, png_infop info_ptr)
+{
+   if(png_ptr == NULL) return;
+   png_debug(1, "in png_read_info\n");
+   /* If we haven't checked all of the PNG signature bytes, do so now. */
+   if (png_ptr->sig_bytes < 8)
+   {
+      png_size_t num_checked = png_ptr->sig_bytes,
+                 num_to_check = 8 - num_checked;
+
+      png_read_data(png_ptr, &(info_ptr->signature[num_checked]), num_to_check);
+      png_ptr->sig_bytes = 8;
+
+      if (png_sig_cmp(info_ptr->signature, num_checked, num_to_check))
+      {
+         if (num_checked < 4 &&
+             png_sig_cmp(info_ptr->signature, num_checked, num_to_check - 4))
+            png_error(png_ptr, "Not a PNG file");
+         else
+            png_error(png_ptr, "PNG file corrupted by ASCII conversion");
+      }
+      if (num_checked < 3)
+         png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
+   }
+
+   for(;;)
+   {
+#ifdef PNG_USE_LOCAL_ARRAYS
+      PNG_CONST PNG_IHDR;
+      PNG_CONST PNG_IDAT;
+      PNG_CONST PNG_IEND;
+      PNG_CONST PNG_PLTE;
+#if defined(PNG_READ_bKGD_SUPPORTED)
+      PNG_CONST PNG_bKGD;
+#endif
+#if defined(PNG_READ_cHRM_SUPPORTED)
+      PNG_CONST PNG_cHRM;
+#endif
+#if defined(PNG_READ_gAMA_SUPPORTED)
+      PNG_CONST PNG_gAMA;
+#endif
+#if defined(PNG_READ_hIST_SUPPORTED)
+      PNG_CONST PNG_hIST;
+#endif
+#if defined(PNG_READ_iCCP_SUPPORTED)
+      PNG_CONST PNG_iCCP;
+#endif
+#if defined(PNG_READ_iTXt_SUPPORTED)
+      PNG_CONST PNG_iTXt;
+#endif
+#if defined(PNG_READ_oFFs_SUPPORTED)
+      PNG_CONST PNG_oFFs;
+#endif
+#if defined(PNG_READ_pCAL_SUPPORTED)
+      PNG_CONST PNG_pCAL;
+#endif
+#if defined(PNG_READ_pHYs_SUPPORTED)
+      PNG_CONST PNG_pHYs;
+#endif
+#if defined(PNG_READ_sBIT_SUPPORTED)
+      PNG_CONST PNG_sBIT;
+#endif
+#if defined(PNG_READ_sCAL_SUPPORTED)
+      PNG_CONST PNG_sCAL;
+#endif
+#if defined(PNG_READ_sPLT_SUPPORTED)
+      PNG_CONST PNG_sPLT;
+#endif
+#if defined(PNG_READ_sRGB_SUPPORTED)
+      PNG_CONST PNG_sRGB;
+#endif
+#if defined(PNG_READ_tEXt_SUPPORTED)
+      PNG_CONST PNG_tEXt;
+#endif
+#if defined(PNG_READ_tIME_SUPPORTED)
+      PNG_CONST PNG_tIME;
+#endif
+#if defined(PNG_READ_tRNS_SUPPORTED)
+      PNG_CONST PNG_tRNS;
+#endif
+#if defined(PNG_READ_zTXt_SUPPORTED)
+      PNG_CONST PNG_zTXt;
+#endif
+#endif /* PNG_USE_LOCAL_ARRAYS */
+      png_byte chunk_length[4];
+      png_uint_32 length;
+
+      png_read_data(png_ptr, chunk_length, 4);
+      length = png_get_uint_31(png_ptr,chunk_length);
+
+      png_reset_crc(png_ptr);
+      png_crc_read(png_ptr, png_ptr->chunk_name, 4);
+
+      png_debug2(0, "Reading %s chunk, length=%lu.\n", png_ptr->chunk_name,
+         length);
+
+      /* This should be a binary subdivision search or a hash for
+       * matching the chunk name rather than a linear search.
+       */
+      if (!png_memcmp(png_ptr->chunk_name, (png_bytep)png_IDAT, 4))
+        if(png_ptr->mode & PNG_AFTER_IDAT)
+          png_ptr->mode |= PNG_HAVE_CHUNK_AFTER_IDAT;
+
+      if (!png_memcmp(png_ptr->chunk_name, png_IHDR, 4))
+         png_handle_IHDR(png_ptr, info_ptr, length);
+      else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
+         png_handle_IEND(png_ptr, info_ptr, length);
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+      else if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name))
+      {
+         if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
+            png_ptr->mode |= PNG_HAVE_IDAT;
+         png_handle_unknown(png_ptr, info_ptr, length);
+         if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
+            png_ptr->mode |= PNG_HAVE_PLTE;
+         else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
+         {
+            if (!(png_ptr->mode & PNG_HAVE_IHDR))
+               png_error(png_ptr, "Missing IHDR before IDAT");
+            else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
+                     !(png_ptr->mode & PNG_HAVE_PLTE))
+               png_error(png_ptr, "Missing PLTE before IDAT");
+            break;
+         }
+      }
+#endif
+      else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
+         png_handle_PLTE(png_ptr, info_ptr, length);
+      else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
+      {
+         if (!(png_ptr->mode & PNG_HAVE_IHDR))
+            png_error(png_ptr, "Missing IHDR before IDAT");
+         else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
+                  !(png_ptr->mode & PNG_HAVE_PLTE))
+            png_error(png_ptr, "Missing PLTE before IDAT");
+
+         png_ptr->idat_size = length;
+         png_ptr->mode |= PNG_HAVE_IDAT;
+         break;
+      }
+#if defined(PNG_READ_bKGD_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))
+         png_handle_bKGD(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_cHRM_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))
+         png_handle_cHRM(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_gAMA_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4))
+         png_handle_gAMA(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_hIST_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))
+         png_handle_hIST(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_oFFs_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))
+         png_handle_oFFs(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_pCAL_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))
+         png_handle_pCAL(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_sCAL_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
+         png_handle_sCAL(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_pHYs_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))
+         png_handle_pHYs(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_sBIT_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))
+         png_handle_sBIT(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_sRGB_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
+         png_handle_sRGB(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_iCCP_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
+         png_handle_iCCP(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_sPLT_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
+         png_handle_sPLT(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_tEXt_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4))
+         png_handle_tEXt(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_tIME_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))
+         png_handle_tIME(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_tRNS_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
+         png_handle_tRNS(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_zTXt_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))
+         png_handle_zTXt(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_iTXt_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))
+         png_handle_iTXt(png_ptr, info_ptr, length);
+#endif
+      else
+         png_handle_unknown(png_ptr, info_ptr, length);
+   }
+}
+#endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
+
+/* optional call to update the users info_ptr structure */
+void PNGAPI
+png_read_update_info(png_structp png_ptr, png_infop info_ptr)
+{
+   png_debug(1, "in png_read_update_info\n");
+   if(png_ptr == NULL) return;
+   if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
+      png_read_start_row(png_ptr);
+   else
+      png_warning(png_ptr,
+      "Ignoring extra png_read_update_info() call; row buffer not reallocated");
+   png_read_transform_info(png_ptr, info_ptr);
+}
+
+#ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
+/* Initialize palette, background, etc, after transformations
+ * are set, but before any reading takes place.  This allows
+ * the user to obtain a gamma-corrected palette, for example.
+ * If the user doesn't call this, we will do it ourselves.
+ */
+void PNGAPI
+png_start_read_image(png_structp png_ptr)
+{
+   png_debug(1, "in png_start_read_image\n");
+   if(png_ptr == NULL) return;
+   if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
+      png_read_start_row(png_ptr);
+}
+#endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
+
+#ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
+void PNGAPI
+png_read_row(png_structp png_ptr, png_bytep row, png_bytep dsp_row)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_CONST PNG_IDAT;
+   PNG_CONST int png_pass_dsp_mask[7] = {0xff, 0x0f, 0xff, 0x33, 0xff, 0x55,
+     0xff};
+   PNG_CONST int png_pass_mask[7] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
+#endif
+   int ret;
+   if(png_ptr == NULL) return;
+   png_debug2(1, "in png_read_row (row %lu, pass %d)\n",
+      png_ptr->row_number, png_ptr->pass);
+   if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
+      png_read_start_row(png_ptr);
+   if (png_ptr->row_number == 0 && png_ptr->pass == 0)
+   {
+   /* check for transforms that have been set but were defined out */
+#if defined(PNG_WRITE_INVERT_SUPPORTED) && !defined(PNG_READ_INVERT_SUPPORTED)
+   if (png_ptr->transformations & PNG_INVERT_MONO)
+      png_warning(png_ptr, "PNG_READ_INVERT_SUPPORTED is not defined.");
+#endif
+#if defined(PNG_WRITE_FILLER_SUPPORTED) && !defined(PNG_READ_FILLER_SUPPORTED)
+   if (png_ptr->transformations & PNG_FILLER)
+      png_warning(png_ptr, "PNG_READ_FILLER_SUPPORTED is not defined.");
+#endif
+#if defined(PNG_WRITE_PACKSWAP_SUPPORTED) && !defined(PNG_READ_PACKSWAP_SUPPORTED)
+   if (png_ptr->transformations & PNG_PACKSWAP)
+      png_warning(png_ptr, "PNG_READ_PACKSWAP_SUPPORTED is not defined.");
+#endif
+#if defined(PNG_WRITE_PACK_SUPPORTED) && !defined(PNG_READ_PACK_SUPPORTED)
+   if (png_ptr->transformations & PNG_PACK)
+      png_warning(png_ptr, "PNG_READ_PACK_SUPPORTED is not defined.");
+#endif
+#if defined(PNG_WRITE_SHIFT_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED)
+   if (png_ptr->transformations & PNG_SHIFT)
+      png_warning(png_ptr, "PNG_READ_SHIFT_SUPPORTED is not defined.");
+#endif
+#if defined(PNG_WRITE_BGR_SUPPORTED) && !defined(PNG_READ_BGR_SUPPORTED)
+   if (png_ptr->transformations & PNG_BGR)
+      png_warning(png_ptr, "PNG_READ_BGR_SUPPORTED is not defined.");
+#endif
+#if defined(PNG_WRITE_SWAP_SUPPORTED) && !defined(PNG_READ_SWAP_SUPPORTED)
+   if (png_ptr->transformations & PNG_SWAP_BYTES)
+      png_warning(png_ptr, "PNG_READ_SWAP_SUPPORTED is not defined.");
+#endif
+   }
+
+#if defined(PNG_READ_INTERLACING_SUPPORTED)
+   /* if interlaced and we do not need a new row, combine row and return */
+   if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
+   {
+      switch (png_ptr->pass)
+      {
+         case 0:
+            if (png_ptr->row_number & 0x07)
+            {
+               if (dsp_row != NULL)
+                  png_combine_row(png_ptr, dsp_row,
+                     png_pass_dsp_mask[png_ptr->pass]);
+               png_read_finish_row(png_ptr);
+               return;
+            }
+            break;
+         case 1:
+            if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
+            {
+               if (dsp_row != NULL)
+                  png_combine_row(png_ptr, dsp_row,
+                     png_pass_dsp_mask[png_ptr->pass]);
+               png_read_finish_row(png_ptr);
+               return;
+            }
+            break;
+         case 2:
+            if ((png_ptr->row_number & 0x07) != 4)
+            {
+               if (dsp_row != NULL && (png_ptr->row_number & 4))
+                  png_combine_row(png_ptr, dsp_row,
+                     png_pass_dsp_mask[png_ptr->pass]);
+               png_read_finish_row(png_ptr);
+               return;
+            }
+            break;
+         case 3:
+            if ((png_ptr->row_number & 3) || png_ptr->width < 3)
+            {
+               if (dsp_row != NULL)
+                  png_combine_row(png_ptr, dsp_row,
+                     png_pass_dsp_mask[png_ptr->pass]);
+               png_read_finish_row(png_ptr);
+               return;
+            }
+            break;
+         case 4:
+            if ((png_ptr->row_number & 3) != 2)
+            {
+               if (dsp_row != NULL && (png_ptr->row_number & 2))
+                  png_combine_row(png_ptr, dsp_row,
+                     png_pass_dsp_mask[png_ptr->pass]);
+               png_read_finish_row(png_ptr);
+               return;
+            }
+            break;
+         case 5:
+            if ((png_ptr->row_number & 1) || png_ptr->width < 2)
+            {
+               if (dsp_row != NULL)
+                  png_combine_row(png_ptr, dsp_row,
+                     png_pass_dsp_mask[png_ptr->pass]);
+               png_read_finish_row(png_ptr);
+               return;
+            }
+            break;
+         case 6:
+            if (!(png_ptr->row_number & 1))
+            {
+               png_read_finish_row(png_ptr);
+               return;
+            }
+            break;
+      }
+   }
+#endif
+
+   if (!(png_ptr->mode & PNG_HAVE_IDAT))
+      png_error(png_ptr, "Invalid attempt to read row data");
+
+   png_ptr->zstream.next_out = png_ptr->row_buf;
+   png_ptr->zstream.avail_out = (uInt)png_ptr->irowbytes;
+   do
+   {
+      if (!(png_ptr->zstream.avail_in))
+      {
+         while (!png_ptr->idat_size)
+         {
+            png_byte chunk_length[4];
+
+            png_crc_finish(png_ptr, 0);
+
+            png_read_data(png_ptr, chunk_length, 4);
+            png_ptr->idat_size = png_get_uint_31(png_ptr,chunk_length);
+
+            png_reset_crc(png_ptr);
+            png_crc_read(png_ptr, png_ptr->chunk_name, 4);
+            if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
+               png_error(png_ptr, "Not enough image data");
+         }
+         png_ptr->zstream.avail_in = (uInt)png_ptr->zbuf_size;
+         png_ptr->zstream.next_in = png_ptr->zbuf;
+         if (png_ptr->zbuf_size > png_ptr->idat_size)
+            png_ptr->zstream.avail_in = (uInt)png_ptr->idat_size;
+         png_crc_read(png_ptr, png_ptr->zbuf,
+            (png_size_t)png_ptr->zstream.avail_in);
+         png_ptr->idat_size -= png_ptr->zstream.avail_in;
+      }
+      ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
+      if (ret == Z_STREAM_END)
+      {
+         if (png_ptr->zstream.avail_out || png_ptr->zstream.avail_in ||
+            png_ptr->idat_size)
+            png_error(png_ptr, "Extra compressed data");
+         png_ptr->mode |= PNG_AFTER_IDAT;
+         png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
+         break;
+      }
+      if (ret != Z_OK)
+         png_error(png_ptr, png_ptr->zstream.msg ? png_ptr->zstream.msg :
+                   "Decompression error");
+
+   } while (png_ptr->zstream.avail_out);
+
+   png_ptr->row_info.color_type = png_ptr->color_type;
+   png_ptr->row_info.width = png_ptr->iwidth;
+   png_ptr->row_info.channels = png_ptr->channels;
+   png_ptr->row_info.bit_depth = png_ptr->bit_depth;
+   png_ptr->row_info.pixel_depth = png_ptr->pixel_depth;
+   png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
+       png_ptr->row_info.width);
+
+   if(png_ptr->row_buf[0])
+   png_read_filter_row(png_ptr, &(png_ptr->row_info),
+      png_ptr->row_buf + 1, png_ptr->prev_row + 1,
+      (int)(png_ptr->row_buf[0]));
+
+   png_memcpy_check(png_ptr, png_ptr->prev_row, png_ptr->row_buf,
+      png_ptr->rowbytes + 1);
+
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
+   if((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
+      (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
+   {
+      /* Intrapixel differencing */
+      png_do_read_intrapixel(&(png_ptr->row_info), png_ptr->row_buf + 1);
+   }
+#endif
+
+
+   if (png_ptr->transformations || (png_ptr->flags&PNG_FLAG_STRIP_ALPHA))
+      png_do_read_transformations(png_ptr);
+
+#if defined(PNG_READ_INTERLACING_SUPPORTED)
+   /* blow up interlaced rows to full size */
+   if (png_ptr->interlaced &&
+      (png_ptr->transformations & PNG_INTERLACE))
+   {
+      if (png_ptr->pass < 6)
+/*       old interface (pre-1.0.9):
+         png_do_read_interlace(&(png_ptr->row_info),
+            png_ptr->row_buf + 1, png_ptr->pass, png_ptr->transformations);
+ */
+         png_do_read_interlace(png_ptr);
+
+      if (dsp_row != NULL)
+         png_combine_row(png_ptr, dsp_row,
+            png_pass_dsp_mask[png_ptr->pass]);
+      if (row != NULL)
+         png_combine_row(png_ptr, row,
+            png_pass_mask[png_ptr->pass]);
+   }
+   else
+#endif
+   {
+      if (row != NULL)
+         png_combine_row(png_ptr, row, 0xff);
+      if (dsp_row != NULL)
+         png_combine_row(png_ptr, dsp_row, 0xff);
+   }
+   png_read_finish_row(png_ptr);
+
+   if (png_ptr->read_row_fn != NULL)
+      (*(png_ptr->read_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
+}
+#endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
+
+#ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
+/* Read one or more rows of image data.  If the image is interlaced,
+ * and png_set_interlace_handling() has been called, the rows need to
+ * contain the contents of the rows from the previous pass.  If the
+ * image has alpha or transparency, and png_handle_alpha()[*] has been
+ * called, the rows contents must be initialized to the contents of the
+ * screen.
+ *
+ * "row" holds the actual image, and pixels are placed in it
+ * as they arrive.  If the image is displayed after each pass, it will
+ * appear to "sparkle" in.  "display_row" can be used to display a
+ * "chunky" progressive image, with finer detail added as it becomes
+ * available.  If you do not want this "chunky" display, you may pass
+ * NULL for display_row.  If you do not want the sparkle display, and
+ * you have not called png_handle_alpha(), you may pass NULL for rows.
+ * If you have called png_handle_alpha(), and the image has either an
+ * alpha channel or a transparency chunk, you must provide a buffer for
+ * rows.  In this case, you do not have to provide a display_row buffer
+ * also, but you may.  If the image is not interlaced, or if you have
+ * not called png_set_interlace_handling(), the display_row buffer will
+ * be ignored, so pass NULL to it.
+ *
+ * [*] png_handle_alpha() does not exist yet, as of this version of libpng
+ */
+
+void PNGAPI
+png_read_rows(png_structp png_ptr, png_bytepp row,
+   png_bytepp display_row, png_uint_32 num_rows)
+{
+   png_uint_32 i;
+   png_bytepp rp;
+   png_bytepp dp;
+
+   png_debug(1, "in png_read_rows\n");
+   if(png_ptr == NULL) return;
+   rp = row;
+   dp = display_row;
+   if (rp != NULL && dp != NULL)
+      for (i = 0; i < num_rows; i++)
+      {
+         png_bytep rptr = *rp++;
+         png_bytep dptr = *dp++;
+
+         png_read_row(png_ptr, rptr, dptr);
+      }
+   else if(rp != NULL)
+      for (i = 0; i < num_rows; i++)
+      {
+         png_bytep rptr = *rp;
+         png_read_row(png_ptr, rptr, png_bytep_NULL);
+         rp++;
+      }
+   else if(dp != NULL)
+      for (i = 0; i < num_rows; i++)
+      {
+         png_bytep dptr = *dp;
+         png_read_row(png_ptr, png_bytep_NULL, dptr);
+         dp++;
+      }
+}
+#endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
+
+#ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
+/* Read the entire image.  If the image has an alpha channel or a tRNS
+ * chunk, and you have called png_handle_alpha()[*], you will need to
+ * initialize the image to the current image that PNG will be overlaying.
+ * We set the num_rows again here, in case it was incorrectly set in
+ * png_read_start_row() by a call to png_read_update_info() or
+ * png_start_read_image() if png_set_interlace_handling() wasn't called
+ * prior to either of these functions like it should have been.  You can
+ * only call this function once.  If you desire to have an image for
+ * each pass of a interlaced image, use png_read_rows() instead.
+ *
+ * [*] png_handle_alpha() does not exist yet, as of this version of libpng
+ */
+void PNGAPI
+png_read_image(png_structp png_ptr, png_bytepp image)
+{
+   png_uint_32 i,image_height;
+   int pass, j;
+   png_bytepp rp;
+
+   png_debug(1, "in png_read_image\n");
+   if(png_ptr == NULL) return;
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+   pass = png_set_interlace_handling(png_ptr);
+#else
+   if (png_ptr->interlaced)
+      png_error(png_ptr,
+        "Cannot read interlaced image -- interlace handler disabled.");
+   pass = 1;
+#endif
+
+
+   image_height=png_ptr->height;
+   png_ptr->num_rows = image_height; /* Make sure this is set correctly */
+
+   for (j = 0; j < pass; j++)
+   {
+      rp = image;
+      for (i = 0; i < image_height; i++)
+      {
+         png_read_row(png_ptr, *rp, png_bytep_NULL);
+         rp++;
+      }
+   }
+}
+#endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
+
+#ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
+/* Read the end of the PNG file.  Will not read past the end of the
+ * file, will verify the end is accurate, and will read any comments
+ * or time information at the end of the file, if info is not NULL.
+ */
+void PNGAPI
+png_read_end(png_structp png_ptr, png_infop info_ptr)
+{
+   png_byte chunk_length[4];
+   png_uint_32 length;
+
+   png_debug(1, "in png_read_end\n");
+   if(png_ptr == NULL) return;
+   png_crc_finish(png_ptr, 0); /* Finish off CRC from last IDAT chunk */
+
+   do
+   {
+#ifdef PNG_USE_LOCAL_ARRAYS
+      PNG_CONST PNG_IHDR;
+      PNG_CONST PNG_IDAT;
+      PNG_CONST PNG_IEND;
+      PNG_CONST PNG_PLTE;
+#if defined(PNG_READ_bKGD_SUPPORTED)
+      PNG_CONST PNG_bKGD;
+#endif
+#if defined(PNG_READ_cHRM_SUPPORTED)
+      PNG_CONST PNG_cHRM;
+#endif
+#if defined(PNG_READ_gAMA_SUPPORTED)
+      PNG_CONST PNG_gAMA;
+#endif
+#if defined(PNG_READ_hIST_SUPPORTED)
+      PNG_CONST PNG_hIST;
+#endif
+#if defined(PNG_READ_iCCP_SUPPORTED)
+      PNG_CONST PNG_iCCP;
+#endif
+#if defined(PNG_READ_iTXt_SUPPORTED)
+      PNG_CONST PNG_iTXt;
+#endif
+#if defined(PNG_READ_oFFs_SUPPORTED)
+      PNG_CONST PNG_oFFs;
+#endif
+#if defined(PNG_READ_pCAL_SUPPORTED)
+      PNG_CONST PNG_pCAL;
+#endif
+#if defined(PNG_READ_pHYs_SUPPORTED)
+      PNG_CONST PNG_pHYs;
+#endif
+#if defined(PNG_READ_sBIT_SUPPORTED)
+      PNG_CONST PNG_sBIT;
+#endif
+#if defined(PNG_READ_sCAL_SUPPORTED)
+      PNG_CONST PNG_sCAL;
+#endif
+#if defined(PNG_READ_sPLT_SUPPORTED)
+      PNG_CONST PNG_sPLT;
+#endif
+#if defined(PNG_READ_sRGB_SUPPORTED)
+      PNG_CONST PNG_sRGB;
+#endif
+#if defined(PNG_READ_tEXt_SUPPORTED)
+      PNG_CONST PNG_tEXt;
+#endif
+#if defined(PNG_READ_tIME_SUPPORTED)
+      PNG_CONST PNG_tIME;
+#endif
+#if defined(PNG_READ_tRNS_SUPPORTED)
+      PNG_CONST PNG_tRNS;
+#endif
+#if defined(PNG_READ_zTXt_SUPPORTED)
+      PNG_CONST PNG_zTXt;
+#endif
+#endif /* PNG_USE_LOCAL_ARRAYS */
+
+      png_read_data(png_ptr, chunk_length, 4);
+      length = png_get_uint_31(png_ptr,chunk_length);
+
+      png_reset_crc(png_ptr);
+      png_crc_read(png_ptr, png_ptr->chunk_name, 4);
+
+      png_debug1(0, "Reading %s chunk.\n", png_ptr->chunk_name);
+
+      if (!png_memcmp(png_ptr->chunk_name, png_IHDR, 4))
+         png_handle_IHDR(png_ptr, info_ptr, length);
+      else if (!png_memcmp(png_ptr->chunk_name, png_IEND, 4))
+         png_handle_IEND(png_ptr, info_ptr, length);
+#ifdef PNG_HANDLE_AS_UNKNOWN_SUPPORTED
+      else if (png_handle_as_unknown(png_ptr, png_ptr->chunk_name))
+      {
+         if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
+         {
+            if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
+               png_error(png_ptr, "Too many IDAT's found");
+         }
+         png_handle_unknown(png_ptr, info_ptr, length);
+         if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
+            png_ptr->mode |= PNG_HAVE_PLTE;
+      }
+#endif
+      else if (!png_memcmp(png_ptr->chunk_name, png_IDAT, 4))
+      {
+         /* Zero length IDATs are legal after the last IDAT has been
+          * read, but not after other chunks have been read.
+          */
+         if ((length > 0) || (png_ptr->mode & PNG_HAVE_CHUNK_AFTER_IDAT))
+            png_error(png_ptr, "Too many IDAT's found");
+         png_crc_finish(png_ptr, length);
+      }
+      else if (!png_memcmp(png_ptr->chunk_name, png_PLTE, 4))
+         png_handle_PLTE(png_ptr, info_ptr, length);
+#if defined(PNG_READ_bKGD_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_bKGD, 4))
+         png_handle_bKGD(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_cHRM_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_cHRM, 4))
+         png_handle_cHRM(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_gAMA_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_gAMA, 4))
+         png_handle_gAMA(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_hIST_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_hIST, 4))
+         png_handle_hIST(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_oFFs_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_oFFs, 4))
+         png_handle_oFFs(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_pCAL_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_pCAL, 4))
+         png_handle_pCAL(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_sCAL_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_sCAL, 4))
+         png_handle_sCAL(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_pHYs_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_pHYs, 4))
+         png_handle_pHYs(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_sBIT_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_sBIT, 4))
+         png_handle_sBIT(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_sRGB_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_sRGB, 4))
+         png_handle_sRGB(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_iCCP_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_iCCP, 4))
+         png_handle_iCCP(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_sPLT_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_sPLT, 4))
+         png_handle_sPLT(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_tEXt_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_tEXt, 4))
+         png_handle_tEXt(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_tIME_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_tIME, 4))
+         png_handle_tIME(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_tRNS_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_tRNS, 4))
+         png_handle_tRNS(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_zTXt_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_zTXt, 4))
+         png_handle_zTXt(png_ptr, info_ptr, length);
+#endif
+#if defined(PNG_READ_iTXt_SUPPORTED)
+      else if (!png_memcmp(png_ptr->chunk_name, png_iTXt, 4))
+         png_handle_iTXt(png_ptr, info_ptr, length);
+#endif
+      else
+         png_handle_unknown(png_ptr, info_ptr, length);
+   } while (!(png_ptr->mode & PNG_HAVE_IEND));
+}
+#endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
+
+/* free all memory used by the read */
+void PNGAPI
+png_destroy_read_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr,
+   png_infopp end_info_ptr_ptr)
+{
+   png_structp png_ptr = NULL;
+   png_infop info_ptr = NULL, end_info_ptr = NULL;
+#ifdef PNG_USER_MEM_SUPPORTED
+   png_free_ptr free_fn;
+   png_voidp mem_ptr;
+#endif
+
+   png_debug(1, "in png_destroy_read_struct\n");
+   if (png_ptr_ptr != NULL)
+      png_ptr = *png_ptr_ptr;
+
+   if (info_ptr_ptr != NULL)
+      info_ptr = *info_ptr_ptr;
+
+   if (end_info_ptr_ptr != NULL)
+      end_info_ptr = *end_info_ptr_ptr;
+
+#ifdef PNG_USER_MEM_SUPPORTED
+   free_fn = png_ptr->free_fn;
+   mem_ptr = png_ptr->mem_ptr;
+#endif
+
+   png_read_destroy(png_ptr, info_ptr, end_info_ptr);
+
+   if (info_ptr != NULL)
+   {
+#if defined(PNG_TEXT_SUPPORTED)
+      png_free_data(png_ptr, info_ptr, PNG_FREE_TEXT, -1);
+#endif
+
+#ifdef PNG_USER_MEM_SUPPORTED
+      png_destroy_struct_2((png_voidp)info_ptr, (png_free_ptr)free_fn,
+          (png_voidp)mem_ptr);
+#else
+      png_destroy_struct((png_voidp)info_ptr);
+#endif
+      *info_ptr_ptr = NULL;
+   }
+
+   if (end_info_ptr != NULL)
+   {
+#if defined(PNG_READ_TEXT_SUPPORTED)
+      png_free_data(png_ptr, end_info_ptr, PNG_FREE_TEXT, -1);
+#endif
+#ifdef PNG_USER_MEM_SUPPORTED
+      png_destroy_struct_2((png_voidp)end_info_ptr, (png_free_ptr)free_fn,
+         (png_voidp)mem_ptr);
+#else
+      png_destroy_struct((png_voidp)end_info_ptr);
+#endif
+      *end_info_ptr_ptr = NULL;
+   }
+
+   if (png_ptr != NULL)
+   {
+#ifdef PNG_USER_MEM_SUPPORTED
+      png_destroy_struct_2((png_voidp)png_ptr, (png_free_ptr)free_fn,
+          (png_voidp)mem_ptr);
+#else
+      png_destroy_struct((png_voidp)png_ptr);
+#endif
+      *png_ptr_ptr = NULL;
+   }
+}
+
+/* free all memory used by the read (old method) */
+void /* PRIVATE */
+png_read_destroy(png_structp png_ptr, png_infop info_ptr, png_infop end_info_ptr)
+{
+#ifdef PNG_SETJMP_SUPPORTED
+   jmp_buf tmp_jmp;
+#endif
+   png_error_ptr error_fn;
+   png_error_ptr warning_fn;
+   png_voidp error_ptr;
+#ifdef PNG_USER_MEM_SUPPORTED
+   png_free_ptr free_fn;
+#endif
+
+   png_debug(1, "in png_read_destroy\n");
+   if (info_ptr != NULL)
+      png_info_destroy(png_ptr, info_ptr);
+
+   if (end_info_ptr != NULL)
+      png_info_destroy(png_ptr, end_info_ptr);
+
+   png_free(png_ptr, png_ptr->zbuf);
+   png_free(png_ptr, png_ptr->big_row_buf);
+   png_free(png_ptr, png_ptr->prev_row);
+#if defined(PNG_READ_DITHER_SUPPORTED)
+   png_free(png_ptr, png_ptr->palette_lookup);
+   png_free(png_ptr, png_ptr->dither_index);
+#endif
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+   png_free(png_ptr, png_ptr->gamma_table);
+#endif
+#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+   png_free(png_ptr, png_ptr->gamma_from_1);
+   png_free(png_ptr, png_ptr->gamma_to_1);
+#endif
+#ifdef PNG_FREE_ME_SUPPORTED
+   if (png_ptr->free_me & PNG_FREE_PLTE)
+      png_zfree(png_ptr, png_ptr->palette);
+   png_ptr->free_me &= ~PNG_FREE_PLTE;
+#else
+   if (png_ptr->flags & PNG_FLAG_FREE_PLTE)
+      png_zfree(png_ptr, png_ptr->palette);
+   png_ptr->flags &= ~PNG_FLAG_FREE_PLTE;
+#endif
+#if defined(PNG_tRNS_SUPPORTED) || \
+    defined(PNG_READ_EXPAND_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
+#ifdef PNG_FREE_ME_SUPPORTED
+   if (png_ptr->free_me & PNG_FREE_TRNS)
+      png_free(png_ptr, png_ptr->trans);
+   png_ptr->free_me &= ~PNG_FREE_TRNS;
+#else
+   if (png_ptr->flags & PNG_FLAG_FREE_TRNS)
+      png_free(png_ptr, png_ptr->trans);
+   png_ptr->flags &= ~PNG_FLAG_FREE_TRNS;
+#endif
+#endif
+#if defined(PNG_READ_hIST_SUPPORTED)
+#ifdef PNG_FREE_ME_SUPPORTED
+   if (png_ptr->free_me & PNG_FREE_HIST)
+      png_free(png_ptr, png_ptr->hist);
+   png_ptr->free_me &= ~PNG_FREE_HIST;
+#else
+   if (png_ptr->flags & PNG_FLAG_FREE_HIST)
+      png_free(png_ptr, png_ptr->hist);
+   png_ptr->flags &= ~PNG_FLAG_FREE_HIST;
+#endif
+#endif
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+   if (png_ptr->gamma_16_table != NULL)
+   {
+      int i;
+      int istop = (1 << (8 - png_ptr->gamma_shift));
+      for (i = 0; i < istop; i++)
+      {
+         png_free(png_ptr, png_ptr->gamma_16_table[i]);
+      }
+   png_free(png_ptr, png_ptr->gamma_16_table);
+   }
+#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+   if (png_ptr->gamma_16_from_1 != NULL)
+   {
+      int i;
+      int istop = (1 << (8 - png_ptr->gamma_shift));
+      for (i = 0; i < istop; i++)
+      {
+         png_free(png_ptr, png_ptr->gamma_16_from_1[i]);
+      }
+   png_free(png_ptr, png_ptr->gamma_16_from_1);
+   }
+   if (png_ptr->gamma_16_to_1 != NULL)
+   {
+      int i;
+      int istop = (1 << (8 - png_ptr->gamma_shift));
+      for (i = 0; i < istop; i++)
+      {
+         png_free(png_ptr, png_ptr->gamma_16_to_1[i]);
+      }
+   png_free(png_ptr, png_ptr->gamma_16_to_1);
+   }
+#endif
+#endif
+#if defined(PNG_TIME_RFC1123_SUPPORTED)
+   png_free(png_ptr, png_ptr->time_buffer);
+#endif
+
+   inflateEnd(&png_ptr->zstream);
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+   png_free(png_ptr, png_ptr->save_buffer);
+#endif
+
+#ifdef PNG_PROGRESSIVE_READ_SUPPORTED
+#ifdef PNG_TEXT_SUPPORTED
+   png_free(png_ptr, png_ptr->current_text);
+#endif /* PNG_TEXT_SUPPORTED */
+#endif /* PNG_PROGRESSIVE_READ_SUPPORTED */
+
+   /* Save the important info out of the png_struct, in case it is
+    * being used again.
+    */
+#ifdef PNG_SETJMP_SUPPORTED
+   png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof (jmp_buf));
+#endif
+
+   error_fn = png_ptr->error_fn;
+   warning_fn = png_ptr->warning_fn;
+   error_ptr = png_ptr->error_ptr;
+#ifdef PNG_USER_MEM_SUPPORTED
+   free_fn = png_ptr->free_fn;
+#endif
+
+   png_memset(png_ptr, 0, png_sizeof (png_struct));
+
+   png_ptr->error_fn = error_fn;
+   png_ptr->warning_fn = warning_fn;
+   png_ptr->error_ptr = error_ptr;
+#ifdef PNG_USER_MEM_SUPPORTED
+   png_ptr->free_fn = free_fn;
+#endif
+
+#ifdef PNG_SETJMP_SUPPORTED
+   png_memcpy(png_ptr->jmpbuf, tmp_jmp, png_sizeof (jmp_buf));
+#endif
+
+}
+
+void PNGAPI
+png_set_read_status_fn(png_structp png_ptr, png_read_status_ptr read_row_fn)
+{
+   if(png_ptr == NULL) return;
+   png_ptr->read_row_fn = read_row_fn;
+}
+
+
+#ifndef PNG_NO_SEQUENTIAL_READ_SUPPORTED
+#if defined(PNG_INFO_IMAGE_SUPPORTED)
+void PNGAPI
+png_read_png(png_structp png_ptr, png_infop info_ptr,
+                           int transforms,
+                           voidp params)
+{
+   int row;
+
+   if(png_ptr == NULL) return;
+#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED)
+   /* invert the alpha channel from opacity to transparency
+    */
+   if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
+       png_set_invert_alpha(png_ptr);
+#endif
+
+   /* png_read_info() gives us all of the information from the
+    * PNG file before the first IDAT (image data chunk).
+    */
+   png_read_info(png_ptr, info_ptr);
+   if (info_ptr->height > PNG_UINT_32_MAX/png_sizeof(png_bytep))
+      png_error(png_ptr,"Image is too high to process with png_read_png()");
+
+   /* -------------- image transformations start here ------------------- */
+
+#if defined(PNG_READ_16_TO_8_SUPPORTED)
+   /* tell libpng to strip 16 bit/color files down to 8 bits per color
+    */
+   if (transforms & PNG_TRANSFORM_STRIP_16)
+       png_set_strip_16(png_ptr);
+#endif
+
+#if defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
+   /* Strip alpha bytes from the input data without combining with
+    * the background (not recommended).
+    */
+   if (transforms & PNG_TRANSFORM_STRIP_ALPHA)
+       png_set_strip_alpha(png_ptr);
+#endif
+
+#if defined(PNG_READ_PACK_SUPPORTED) && !defined(PNG_READ_EXPAND_SUPPORTED)
+   /* Extract multiple pixels with bit depths of 1, 2, or 4 from a single
+    * byte into separate bytes (useful for paletted and grayscale images).
+    */
+   if (transforms & PNG_TRANSFORM_PACKING)
+       png_set_packing(png_ptr);
+#endif
+
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+   /* Change the order of packed pixels to least significant bit first
+    * (not useful if you are using png_set_packing).
+    */
+   if (transforms & PNG_TRANSFORM_PACKSWAP)
+       png_set_packswap(png_ptr);
+#endif
+
+#if defined(PNG_READ_EXPAND_SUPPORTED)
+   /* Expand paletted colors into true RGB triplets
+    * Expand grayscale images to full 8 bits from 1, 2, or 4 bits/pixel
+    * Expand paletted or RGB images with transparency to full alpha
+    * channels so the data will be available as RGBA quartets.
+    */
+   if (transforms & PNG_TRANSFORM_EXPAND)
+       if ((png_ptr->bit_depth < 8) ||
+           (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE) ||
+           (png_get_valid(png_ptr, info_ptr, PNG_INFO_tRNS)))
+         png_set_expand(png_ptr);
+#endif
+
+   /* We don't handle background color or gamma transformation or dithering.
+    */
+
+#if defined(PNG_READ_INVERT_SUPPORTED)
+   /* invert monochrome files to have 0 as white and 1 as black
+    */
+   if (transforms & PNG_TRANSFORM_INVERT_MONO)
+       png_set_invert_mono(png_ptr);
+#endif
+
+#if defined(PNG_READ_SHIFT_SUPPORTED)
+   /* If you want to shift the pixel values from the range [0,255] or
+    * [0,65535] to the original [0,7] or [0,31], or whatever range the
+    * colors were originally in:
+    */
+   if ((transforms & PNG_TRANSFORM_SHIFT)
+       && png_get_valid(png_ptr, info_ptr, PNG_INFO_sBIT))
+   {
+      png_color_8p sig_bit;
+
+      png_get_sBIT(png_ptr, info_ptr, &sig_bit);
+      png_set_shift(png_ptr, sig_bit);
+   }
+#endif
+
+#if defined(PNG_READ_BGR_SUPPORTED)
+   /* flip the RGB pixels to BGR (or RGBA to BGRA)
+    */
+   if (transforms & PNG_TRANSFORM_BGR)
+       png_set_bgr(png_ptr);
+#endif
+
+#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED)
+   /* swap the RGBA or GA data to ARGB or AG (or BGRA to ABGR)
+    */
+   if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
+       png_set_swap_alpha(png_ptr);
+#endif
+
+#if defined(PNG_READ_SWAP_SUPPORTED)
+   /* swap bytes of 16 bit files to least significant byte first
+    */
+   if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
+       png_set_swap(png_ptr);
+#endif
+
+   /* We don't handle adding filler bytes */
+
+   /* Optional call to gamma correct and add the background to the palette
+    * and update info structure.  REQUIRED if you are expecting libpng to
+    * update the palette for you (i.e., you selected such a transform above).
+    */
+   png_read_update_info(png_ptr, info_ptr);
+
+   /* -------------- image transformations end here ------------------- */
+
+#ifdef PNG_FREE_ME_SUPPORTED
+   png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
+#endif
+   if(info_ptr->row_pointers == NULL)
+   {
+      info_ptr->row_pointers = (png_bytepp)png_malloc(png_ptr,
+         info_ptr->height * png_sizeof(png_bytep));
+#ifdef PNG_FREE_ME_SUPPORTED
+      info_ptr->free_me |= PNG_FREE_ROWS;
+#endif
+      for (row = 0; row < (int)info_ptr->height; row++)
+      {
+         info_ptr->row_pointers[row] = (png_bytep)png_malloc(png_ptr,
+            png_get_rowbytes(png_ptr, info_ptr));
+      }
+   }
+
+   png_read_image(png_ptr, info_ptr->row_pointers);
+   info_ptr->valid |= PNG_INFO_IDAT;
+
+   /* read rest of file, and get additional chunks in info_ptr - REQUIRED */
+   png_read_end(png_ptr, info_ptr);
+
+   transforms = transforms; /* quiet compiler warnings */
+   params = params;
+
+}
+#endif /* PNG_INFO_IMAGE_SUPPORTED */
+#endif /* PNG_NO_SEQUENTIAL_READ_SUPPORTED */
+#endif /* PNG_READ_SUPPORTED */
diff --git a/distrib/libpng-1.2.19/pngrio.c b/distrib/libpng-1.2.19/pngrio.c
new file mode 100644
index 0000000..7d2522f
--- /dev/null
+++ b/distrib/libpng-1.2.19/pngrio.c
@@ -0,0 +1,167 @@
+
+/* pngrio.c - functions for data input
+ *
+ * Last changed in libpng 1.2.13 November 13, 2006
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1998-2006 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This file provides a location for all input.  Users who need
+ * special handling are expected to write a function that has the same
+ * arguments as this and performs a similar function, but that possibly
+ * has a different input method.  Note that you shouldn't change this
+ * function, but rather write a replacement function and then make
+ * libpng use it at run time with png_set_read_fn(...).
+ */
+
+#define PNG_INTERNAL
+#include "png.h"
+
+#if defined(PNG_READ_SUPPORTED)
+
+/* Read the data from whatever input you are using.  The default routine
+   reads from a file pointer.  Note that this routine sometimes gets called
+   with very small lengths, so you should implement some kind of simple
+   buffering if you are using unbuffered reads.  This should never be asked
+   to read more then 64K on a 16 bit machine. */
+void /* PRIVATE */
+png_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
+{
+   png_debug1(4,"reading %d bytes\n", (int)length);
+   if (png_ptr->read_data_fn != NULL)
+      (*(png_ptr->read_data_fn))(png_ptr, data, length);
+   else
+      png_error(png_ptr, "Call to NULL read function");
+}
+
+#if !defined(PNG_NO_STDIO)
+/* This is the function that does the actual reading of data.  If you are
+   not reading from a standard C stream, you should create a replacement
+   read_data function and use it at run time with png_set_read_fn(), rather
+   than changing the library. */
+#ifndef USE_FAR_KEYWORD
+void PNGAPI
+png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
+{
+   png_size_t check;
+
+   if(png_ptr == NULL) return;
+   /* fread() returns 0 on error, so it is OK to store this in a png_size_t
+    * instead of an int, which is what fread() actually returns.
+    */
+#if defined(_WIN32_WCE)
+   if ( !ReadFile((HANDLE)(png_ptr->io_ptr), data, length, &check, NULL) )
+      check = 0;
+#else
+   check = (png_size_t)fread(data, (png_size_t)1, length,
+      (png_FILE_p)png_ptr->io_ptr);
+#endif
+
+   if (check != length)
+      png_error(png_ptr, "Read Error");
+}
+#else
+/* this is the model-independent version. Since the standard I/O library
+   can't handle far buffers in the medium and small models, we have to copy
+   the data.
+*/
+
+#define NEAR_BUF_SIZE 1024
+#define MIN(a,b) (a <= b ? a : b)
+
+static void PNGAPI
+png_default_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
+{
+   int check;
+   png_byte *n_data;
+   png_FILE_p io_ptr;
+
+   if(png_ptr == NULL) return;
+   /* Check if data really is near. If so, use usual code. */
+   n_data = (png_byte *)CVT_PTR_NOCHECK(data);
+   io_ptr = (png_FILE_p)CVT_PTR(png_ptr->io_ptr);
+   if ((png_bytep)n_data == data)
+   {
+#if defined(_WIN32_WCE)
+      if ( !ReadFile((HANDLE)(png_ptr->io_ptr), data, length, &check, NULL) )
+         check = 0;
+#else
+      check = fread(n_data, 1, length, io_ptr);
+#endif
+   }
+   else
+   {
+      png_byte buf[NEAR_BUF_SIZE];
+      png_size_t read, remaining, err;
+      check = 0;
+      remaining = length;
+      do
+      {
+         read = MIN(NEAR_BUF_SIZE, remaining);
+#if defined(_WIN32_WCE)
+         if ( !ReadFile((HANDLE)(io_ptr), buf, read, &err, NULL) )
+            err = 0;
+#else
+         err = fread(buf, (png_size_t)1, read, io_ptr);
+#endif
+         png_memcpy(data, buf, read); /* copy far buffer to near buffer */
+         if(err != read)
+            break;
+         else
+            check += err;
+         data += read;
+         remaining -= read;
+      }
+      while (remaining != 0);
+   }
+   if ((png_uint_32)check != (png_uint_32)length)
+      png_error(png_ptr, "read Error");
+}
+#endif
+#endif
+
+/* This function allows the application to supply a new input function
+   for libpng if standard C streams aren't being used.
+
+   This function takes as its arguments:
+   png_ptr      - pointer to a png input data structure
+   io_ptr       - pointer to user supplied structure containing info about
+                  the input functions.  May be NULL.
+   read_data_fn - pointer to a new input function that takes as its
+                  arguments a pointer to a png_struct, a pointer to
+                  a location where input data can be stored, and a 32-bit
+                  unsigned int that is the number of bytes to be read.
+                  To exit and output any fatal error messages the new write
+                  function should call png_error(png_ptr, "Error msg"). */
+void PNGAPI
+png_set_read_fn(png_structp png_ptr, png_voidp io_ptr,
+   png_rw_ptr read_data_fn)
+{
+   if(png_ptr == NULL) return;
+   png_ptr->io_ptr = io_ptr;
+
+#if !defined(PNG_NO_STDIO)
+   if (read_data_fn != NULL)
+      png_ptr->read_data_fn = read_data_fn;
+   else
+      png_ptr->read_data_fn = png_default_read_data;
+#else
+   png_ptr->read_data_fn = read_data_fn;
+#endif
+
+   /* It is an error to write to a read device */
+   if (png_ptr->write_data_fn != NULL)
+   {
+      png_ptr->write_data_fn = NULL;
+      png_warning(png_ptr,
+         "It's an error to set both read_data_fn and write_data_fn in the ");
+      png_warning(png_ptr,
+         "same structure.  Resetting write_data_fn to NULL.");
+   }
+
+#if defined(PNG_WRITE_FLUSH_SUPPORTED)
+   png_ptr->output_flush_fn = NULL;
+#endif
+}
+#endif /* PNG_READ_SUPPORTED */
diff --git a/distrib/libpng-1.2.19/pngrtran.c b/distrib/libpng-1.2.19/pngrtran.c
new file mode 100644
index 0000000..3f04051
--- /dev/null
+++ b/distrib/libpng-1.2.19/pngrtran.c
@@ -0,0 +1,4284 @@
+
+/* pngrtran.c - transforms the data in a row for PNG readers
+ *
+ * Last changed in libpng 1.2.19 August 18, 2007
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1998-2007 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This file contains functions optionally called by an application
+ * in order to tell libpng how to handle data when reading a PNG.
+ * Transformations that are used in both reading and writing are
+ * in pngtrans.c.
+ */
+
+#define PNG_INTERNAL
+#include "png.h"
+
+#if defined(PNG_READ_SUPPORTED)
+
+/* Set the action on getting a CRC error for an ancillary or critical chunk. */
+void PNGAPI
+png_set_crc_action(png_structp png_ptr, int crit_action, int ancil_action)
+{
+   png_debug(1, "in png_set_crc_action\n");
+   /* Tell libpng how we react to CRC errors in critical chunks */
+   if(png_ptr == NULL) return;
+   switch (crit_action)
+   {
+      case PNG_CRC_NO_CHANGE:                        /* leave setting as is */
+         break;
+      case PNG_CRC_WARN_USE:                               /* warn/use data */
+         png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
+         png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE;
+         break;
+      case PNG_CRC_QUIET_USE:                             /* quiet/use data */
+         png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
+         png_ptr->flags |= PNG_FLAG_CRC_CRITICAL_USE |
+                           PNG_FLAG_CRC_CRITICAL_IGNORE;
+         break;
+      case PNG_CRC_WARN_DISCARD:    /* not a valid action for critical data */
+         png_warning(png_ptr, "Can't discard critical data on CRC error.");
+      case PNG_CRC_ERROR_QUIT:                                /* error/quit */
+      case PNG_CRC_DEFAULT:
+      default:
+         png_ptr->flags &= ~PNG_FLAG_CRC_CRITICAL_MASK;
+         break;
+   }
+
+   switch (ancil_action)
+   {
+      case PNG_CRC_NO_CHANGE:                       /* leave setting as is */
+         break;
+      case PNG_CRC_WARN_USE:                              /* warn/use data */
+         png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
+         png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE;
+         break;
+      case PNG_CRC_QUIET_USE:                            /* quiet/use data */
+         png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
+         png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_USE |
+                           PNG_FLAG_CRC_ANCILLARY_NOWARN;
+         break;
+      case PNG_CRC_ERROR_QUIT:                               /* error/quit */
+         png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
+         png_ptr->flags |= PNG_FLAG_CRC_ANCILLARY_NOWARN;
+         break;
+      case PNG_CRC_WARN_DISCARD:                      /* warn/discard data */
+      case PNG_CRC_DEFAULT:
+      default:
+         png_ptr->flags &= ~PNG_FLAG_CRC_ANCILLARY_MASK;
+         break;
+   }
+}
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
+    defined(PNG_FLOATING_POINT_SUPPORTED)
+/* handle alpha and tRNS via a background color */
+void PNGAPI
+png_set_background(png_structp png_ptr,
+   png_color_16p background_color, int background_gamma_code,
+   int need_expand, double background_gamma)
+{
+   png_debug(1, "in png_set_background\n");
+   if(png_ptr == NULL) return;
+   if (background_gamma_code == PNG_BACKGROUND_GAMMA_UNKNOWN)
+   {
+      png_warning(png_ptr, "Application must supply a known background gamma");
+      return;
+   }
+
+   png_ptr->transformations |= PNG_BACKGROUND;
+   png_memcpy(&(png_ptr->background), background_color,
+      png_sizeof(png_color_16));
+   png_ptr->background_gamma = (float)background_gamma;
+   png_ptr->background_gamma_type = (png_byte)(background_gamma_code);
+   png_ptr->transformations |= (need_expand ? PNG_BACKGROUND_EXPAND : 0);
+}
+#endif
+
+#if defined(PNG_READ_16_TO_8_SUPPORTED)
+/* strip 16 bit depth files to 8 bit depth */
+void PNGAPI
+png_set_strip_16(png_structp png_ptr)
+{
+   png_debug(1, "in png_set_strip_16\n");
+   if(png_ptr == NULL) return;
+   png_ptr->transformations |= PNG_16_TO_8;
+}
+#endif
+
+#if defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
+void PNGAPI
+png_set_strip_alpha(png_structp png_ptr)
+{
+   png_debug(1, "in png_set_strip_alpha\n");
+   if(png_ptr == NULL) return;
+   png_ptr->flags |= PNG_FLAG_STRIP_ALPHA;
+}
+#endif
+
+#if defined(PNG_READ_DITHER_SUPPORTED)
+/* Dither file to 8 bit.  Supply a palette, the current number
+ * of elements in the palette, the maximum number of elements
+ * allowed, and a histogram if possible.  If the current number
+ * of colors is greater then the maximum number, the palette will be
+ * modified to fit in the maximum number.  "full_dither" indicates
+ * whether we need a dithering cube set up for RGB images, or if we
+ * simply are reducing the number of colors in a paletted image.
+ */
+
+typedef struct png_dsort_struct
+{
+   struct png_dsort_struct FAR * next;
+   png_byte left;
+   png_byte right;
+} png_dsort;
+typedef png_dsort FAR *       png_dsortp;
+typedef png_dsort FAR * FAR * png_dsortpp;
+
+void PNGAPI
+png_set_dither(png_structp png_ptr, png_colorp palette,
+   int num_palette, int maximum_colors, png_uint_16p histogram,
+   int full_dither)
+{
+   png_debug(1, "in png_set_dither\n");
+   if(png_ptr == NULL) return;
+   png_ptr->transformations |= PNG_DITHER;
+
+   if (!full_dither)
+   {
+      int i;
+
+      png_ptr->dither_index = (png_bytep)png_malloc(png_ptr,
+         (png_uint_32)(num_palette * png_sizeof (png_byte)));
+      for (i = 0; i < num_palette; i++)
+         png_ptr->dither_index[i] = (png_byte)i;
+   }
+
+   if (num_palette > maximum_colors)
+   {
+      if (histogram != NULL)
+      {
+         /* This is easy enough, just throw out the least used colors.
+            Perhaps not the best solution, but good enough. */
+
+         int i;
+
+         /* initialize an array to sort colors */
+         png_ptr->dither_sort = (png_bytep)png_malloc(png_ptr,
+            (png_uint_32)(num_palette * png_sizeof (png_byte)));
+
+         /* initialize the dither_sort array */
+         for (i = 0; i < num_palette; i++)
+            png_ptr->dither_sort[i] = (png_byte)i;
+
+         /* Find the least used palette entries by starting a
+            bubble sort, and running it until we have sorted
+            out enough colors.  Note that we don't care about
+            sorting all the colors, just finding which are
+            least used. */
+
+         for (i = num_palette - 1; i >= maximum_colors; i--)
+         {
+            int done; /* to stop early if the list is pre-sorted */
+            int j;
+
+            done = 1;
+            for (j = 0; j < i; j++)
+            {
+               if (histogram[png_ptr->dither_sort[j]]
+                   < histogram[png_ptr->dither_sort[j + 1]])
+               {
+                  png_byte t;
+
+                  t = png_ptr->dither_sort[j];
+                  png_ptr->dither_sort[j] = png_ptr->dither_sort[j + 1];
+                  png_ptr->dither_sort[j + 1] = t;
+                  done = 0;
+               }
+            }
+            if (done)
+               break;
+         }
+
+         /* swap the palette around, and set up a table, if necessary */
+         if (full_dither)
+         {
+            int j = num_palette;
+
+            /* put all the useful colors within the max, but don't
+               move the others */
+            for (i = 0; i < maximum_colors; i++)
+            {
+               if ((int)png_ptr->dither_sort[i] >= maximum_colors)
+               {
+                  do
+                     j--;
+                  while ((int)png_ptr->dither_sort[j] >= maximum_colors);
+                  palette[i] = palette[j];
+               }
+            }
+         }
+         else
+         {
+            int j = num_palette;
+
+            /* move all the used colors inside the max limit, and
+               develop a translation table */
+            for (i = 0; i < maximum_colors; i++)
+            {
+               /* only move the colors we need to */
+               if ((int)png_ptr->dither_sort[i] >= maximum_colors)
+               {
+                  png_color tmp_color;
+
+                  do
+                     j--;
+                  while ((int)png_ptr->dither_sort[j] >= maximum_colors);
+
+                  tmp_color = palette[j];
+                  palette[j] = palette[i];
+                  palette[i] = tmp_color;
+                  /* indicate where the color went */
+                  png_ptr->dither_index[j] = (png_byte)i;
+                  png_ptr->dither_index[i] = (png_byte)j;
+               }
+            }
+
+            /* find closest color for those colors we are not using */
+            for (i = 0; i < num_palette; i++)
+            {
+               if ((int)png_ptr->dither_index[i] >= maximum_colors)
+               {
+                  int min_d, k, min_k, d_index;
+
+                  /* find the closest color to one we threw out */
+                  d_index = png_ptr->dither_index[i];
+                  min_d = PNG_COLOR_DIST(palette[d_index], palette[0]);
+                  for (k = 1, min_k = 0; k < maximum_colors; k++)
+                  {
+                     int d;
+
+                     d = PNG_COLOR_DIST(palette[d_index], palette[k]);
+
+                     if (d < min_d)
+                     {
+                        min_d = d;
+                        min_k = k;
+                     }
+                  }
+                  /* point to closest color */
+                  png_ptr->dither_index[i] = (png_byte)min_k;
+               }
+            }
+         }
+         png_free(png_ptr, png_ptr->dither_sort);
+         png_ptr->dither_sort=NULL;
+      }
+      else
+      {
+         /* This is much harder to do simply (and quickly).  Perhaps
+            we need to go through a median cut routine, but those
+            don't always behave themselves with only a few colors
+            as input.  So we will just find the closest two colors,
+            and throw out one of them (chosen somewhat randomly).
+            [We don't understand this at all, so if someone wants to
+             work on improving it, be our guest - AED, GRP]
+            */
+         int i;
+         int max_d;
+         int num_new_palette;
+         png_dsortp t;
+         png_dsortpp hash;
+
+         t=NULL;
+
+         /* initialize palette index arrays */
+         png_ptr->index_to_palette = (png_bytep)png_malloc(png_ptr,
+            (png_uint_32)(num_palette * png_sizeof (png_byte)));
+         png_ptr->palette_to_index = (png_bytep)png_malloc(png_ptr,
+            (png_uint_32)(num_palette * png_sizeof (png_byte)));
+
+         /* initialize the sort array */
+         for (i = 0; i < num_palette; i++)
+         {
+            png_ptr->index_to_palette[i] = (png_byte)i;
+            png_ptr->palette_to_index[i] = (png_byte)i;
+         }
+
+         hash = (png_dsortpp)png_malloc(png_ptr, (png_uint_32)(769 *
+            png_sizeof (png_dsortp)));
+         for (i = 0; i < 769; i++)
+            hash[i] = NULL;
+/*         png_memset(hash, 0, 769 * png_sizeof (png_dsortp)); */
+
+         num_new_palette = num_palette;
+
+         /* initial wild guess at how far apart the farthest pixel
+            pair we will be eliminating will be.  Larger
+            numbers mean more areas will be allocated, Smaller
+            numbers run the risk of not saving enough data, and
+            having to do this all over again.
+
+            I have not done extensive checking on this number.
+            */
+         max_d = 96;
+
+         while (num_new_palette > maximum_colors)
+         {
+            for (i = 0; i < num_new_palette - 1; i++)
+            {
+               int j;
+
+               for (j = i + 1; j < num_new_palette; j++)
+               {
+                  int d;
+
+                  d = PNG_COLOR_DIST(palette[i], palette[j]);
+
+                  if (d <= max_d)
+                  {
+
+                     t = (png_dsortp)png_malloc_warn(png_ptr,
+                         (png_uint_32)(png_sizeof(png_dsort)));
+                     if (t == NULL)
+                         break;
+                     t->next = hash[d];
+                     t->left = (png_byte)i;
+                     t->right = (png_byte)j;
+                     hash[d] = t;
+                  }
+               }
+               if (t == NULL)
+                  break;
+            }
+
+            if (t != NULL)
+            for (i = 0; i <= max_d; i++)
+            {
+               if (hash[i] != NULL)
+               {
+                  png_dsortp p;
+
+                  for (p = hash[i]; p; p = p->next)
+                  {
+                     if ((int)png_ptr->index_to_palette[p->left]
+                        < num_new_palette &&
+                        (int)png_ptr->index_to_palette[p->right]
+                        < num_new_palette)
+                     {
+                        int j, next_j;
+
+                        if (num_new_palette & 0x01)
+                        {
+                           j = p->left;
+                           next_j = p->right;
+                        }
+                        else
+                        {
+                           j = p->right;
+                           next_j = p->left;
+                        }
+
+                        num_new_palette--;
+                        palette[png_ptr->index_to_palette[j]]
+                          = palette[num_new_palette];
+                        if (!full_dither)
+                        {
+                           int k;
+
+                           for (k = 0; k < num_palette; k++)
+                           {
+                              if (png_ptr->dither_index[k] ==
+                                 png_ptr->index_to_palette[j])
+                                 png_ptr->dither_index[k] =
+                                    png_ptr->index_to_palette[next_j];
+                              if ((int)png_ptr->dither_index[k] ==
+                                 num_new_palette)
+                                 png_ptr->dither_index[k] =
+                                    png_ptr->index_to_palette[j];
+                           }
+                        }
+
+                        png_ptr->index_to_palette[png_ptr->palette_to_index
+                           [num_new_palette]] = png_ptr->index_to_palette[j];
+                        png_ptr->palette_to_index[png_ptr->index_to_palette[j]]
+                           = png_ptr->palette_to_index[num_new_palette];
+
+                        png_ptr->index_to_palette[j] = (png_byte)num_new_palette;
+                        png_ptr->palette_to_index[num_new_palette] = (png_byte)j;
+                     }
+                     if (num_new_palette <= maximum_colors)
+                        break;
+                  }
+                  if (num_new_palette <= maximum_colors)
+                     break;
+               }
+            }
+
+            for (i = 0; i < 769; i++)
+            {
+               if (hash[i] != NULL)
+               {
+                  png_dsortp p = hash[i];
+                  while (p)
+                  {
+                     t = p->next;
+                     png_free(png_ptr, p);
+                     p = t;
+                  }
+               }
+               hash[i] = 0;
+            }
+            max_d += 96;
+         }
+         png_free(png_ptr, hash);
+         png_free(png_ptr, png_ptr->palette_to_index);
+         png_free(png_ptr, png_ptr->index_to_palette);
+         png_ptr->palette_to_index=NULL;
+         png_ptr->index_to_palette=NULL;
+      }
+      num_palette = maximum_colors;
+   }
+   if (png_ptr->palette == NULL)
+   {
+      png_ptr->palette = palette;
+   }
+   png_ptr->num_palette = (png_uint_16)num_palette;
+
+   if (full_dither)
+   {
+      int i;
+      png_bytep distance;
+      int total_bits = PNG_DITHER_RED_BITS + PNG_DITHER_GREEN_BITS +
+         PNG_DITHER_BLUE_BITS;
+      int num_red = (1 << PNG_DITHER_RED_BITS);
+      int num_green = (1 << PNG_DITHER_GREEN_BITS);
+      int num_blue = (1 << PNG_DITHER_BLUE_BITS);
+      png_size_t num_entries = ((png_size_t)1 << total_bits);
+
+      png_ptr->palette_lookup = (png_bytep )png_malloc(png_ptr,
+         (png_uint_32)(num_entries * png_sizeof (png_byte)));
+
+      png_memset(png_ptr->palette_lookup, 0, num_entries *
+         png_sizeof (png_byte));
+
+      distance = (png_bytep)png_malloc(png_ptr, (png_uint_32)(num_entries *
+         png_sizeof(png_byte)));
+
+      png_memset(distance, 0xff, num_entries * png_sizeof(png_byte));
+
+      for (i = 0; i < num_palette; i++)
+      {
+         int ir, ig, ib;
+         int r = (palette[i].red >> (8 - PNG_DITHER_RED_BITS));
+         int g = (palette[i].green >> (8 - PNG_DITHER_GREEN_BITS));
+         int b = (palette[i].blue >> (8 - PNG_DITHER_BLUE_BITS));
+
+         for (ir = 0; ir < num_red; ir++)
+         {
+            /* int dr = abs(ir - r); */
+            int dr = ((ir > r) ? ir - r : r - ir);
+            int index_r = (ir << (PNG_DITHER_BLUE_BITS + PNG_DITHER_GREEN_BITS));
+
+            for (ig = 0; ig < num_green; ig++)
+            {
+               /* int dg = abs(ig - g); */
+               int dg = ((ig > g) ? ig - g : g - ig);
+               int dt = dr + dg;
+               int dm = ((dr > dg) ? dr : dg);
+               int index_g = index_r | (ig << PNG_DITHER_BLUE_BITS);
+
+               for (ib = 0; ib < num_blue; ib++)
+               {
+                  int d_index = index_g | ib;
+                  /* int db = abs(ib - b); */
+                  int db = ((ib > b) ? ib - b : b - ib);
+                  int dmax = ((dm > db) ? dm : db);
+                  int d = dmax + dt + db;
+
+                  if (d < (int)distance[d_index])
+                  {
+                     distance[d_index] = (png_byte)d;
+                     png_ptr->palette_lookup[d_index] = (png_byte)i;
+                  }
+               }
+            }
+         }
+      }
+
+      png_free(png_ptr, distance);
+   }
+}
+#endif
+
+#if defined(PNG_READ_GAMMA_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED)
+/* Transform the image from the file_gamma to the screen_gamma.  We
+ * only do transformations on images where the file_gamma and screen_gamma
+ * are not close reciprocals, otherwise it slows things down slightly, and
+ * also needlessly introduces small errors.
+ *
+ * We will turn off gamma transformation later if no semitransparent entries
+ * are present in the tRNS array for palette images.  We can't do it here
+ * because we don't necessarily have the tRNS chunk yet.
+ */
+void PNGAPI
+png_set_gamma(png_structp png_ptr, double scrn_gamma, double file_gamma)
+{
+   png_debug(1, "in png_set_gamma\n");
+   if(png_ptr == NULL) return;
+   if ((fabs(scrn_gamma * file_gamma - 1.0) > PNG_GAMMA_THRESHOLD) ||
+       (png_ptr->color_type & PNG_COLOR_MASK_ALPHA) ||
+       (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE))
+     png_ptr->transformations |= PNG_GAMMA;
+   png_ptr->gamma = (float)file_gamma;
+   png_ptr->screen_gamma = (float)scrn_gamma;
+}
+#endif
+
+#if defined(PNG_READ_EXPAND_SUPPORTED)
+/* Expand paletted images to RGB, expand grayscale images of
+ * less than 8-bit depth to 8-bit depth, and expand tRNS chunks
+ * to alpha channels.
+ */
+void PNGAPI
+png_set_expand(png_structp png_ptr)
+{
+   png_debug(1, "in png_set_expand\n");
+   if(png_ptr == NULL) return;
+   png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
+#ifdef PNG_WARN_UNINITIALIZED_ROW
+   png_ptr->flags &= !(PNG_FLAG_ROW_INIT);
+#endif
+}
+
+/* GRR 19990627:  the following three functions currently are identical
+ *  to png_set_expand().  However, it is entirely reasonable that someone
+ *  might wish to expand an indexed image to RGB but *not* expand a single,
+ *  fully transparent palette entry to a full alpha channel--perhaps instead
+ *  convert tRNS to the grayscale/RGB format (16-bit RGB value), or replace
+ *  the transparent color with a particular RGB value, or drop tRNS entirely.
+ *  IOW, a future version of the library may make the transformations flag
+ *  a bit more fine-grained, with separate bits for each of these three
+ *  functions.
+ *
+ *  More to the point, these functions make it obvious what libpng will be
+ *  doing, whereas "expand" can (and does) mean any number of things.
+ *
+ *  GRP 20060307: In libpng-1.4.0, png_set_gray_1_2_4_to_8() was modified
+ *  to expand only the sample depth but not to expand the tRNS to alpha.
+ */
+
+/* Expand paletted images to RGB. */
+void PNGAPI
+png_set_palette_to_rgb(png_structp png_ptr)
+{
+   png_debug(1, "in png_set_palette_to_rgb\n");
+   if(png_ptr == NULL) return;
+   png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
+#ifdef PNG_WARN_UNINITIALIZED_ROW
+   png_ptr->flags &= !(PNG_FLAG_ROW_INIT);
+#endif
+}
+
+#if !defined(PNG_1_0_X)
+/* Expand grayscale images of less than 8-bit depth to 8 bits. */
+void PNGAPI
+png_set_expand_gray_1_2_4_to_8(png_structp png_ptr)
+{
+   png_debug(1, "in png_set_expand_gray_1_2_4_to_8\n");
+   if(png_ptr == NULL) return;
+   png_ptr->transformations |= PNG_EXPAND;
+#ifdef PNG_WARN_UNINITIALIZED_ROW
+   png_ptr->flags &= !(PNG_FLAG_ROW_INIT);
+#endif
+}
+#endif
+
+#if defined(PNG_1_0_X) || defined(PNG_1_2_X)
+/* Expand grayscale images of less than 8-bit depth to 8 bits. */
+/* Deprecated as of libpng-1.2.9 */
+void PNGAPI
+png_set_gray_1_2_4_to_8(png_structp png_ptr)
+{
+   png_debug(1, "in png_set_gray_1_2_4_to_8\n");
+   if(png_ptr == NULL) return;
+   png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
+}
+#endif
+
+
+/* Expand tRNS chunks to alpha channels. */
+void PNGAPI
+png_set_tRNS_to_alpha(png_structp png_ptr)
+{
+   png_debug(1, "in png_set_tRNS_to_alpha\n");
+   png_ptr->transformations |= (PNG_EXPAND | PNG_EXPAND_tRNS);
+#ifdef PNG_WARN_UNINITIALIZED_ROW
+   png_ptr->flags &= !(PNG_FLAG_ROW_INIT);
+#endif
+}
+#endif /* defined(PNG_READ_EXPAND_SUPPORTED) */
+
+#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
+void PNGAPI
+png_set_gray_to_rgb(png_structp png_ptr)
+{
+   png_debug(1, "in png_set_gray_to_rgb\n");
+   png_ptr->transformations |= PNG_GRAY_TO_RGB;
+#ifdef PNG_WARN_UNINITIALIZED_ROW
+   png_ptr->flags &= !(PNG_FLAG_ROW_INIT);
+#endif
+}
+#endif
+
+#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+#if defined(PNG_FLOATING_POINT_SUPPORTED)
+/* Convert a RGB image to a grayscale of the same width.  This allows us,
+ * for example, to convert a 24 bpp RGB image into an 8 bpp grayscale image.
+ */
+
+void PNGAPI
+png_set_rgb_to_gray(png_structp png_ptr, int error_action, double red,
+   double green)
+{
+      int red_fixed = (int)((float)red*100000.0 + 0.5);
+      int green_fixed = (int)((float)green*100000.0 + 0.5);
+      if(png_ptr == NULL) return;
+      png_set_rgb_to_gray_fixed(png_ptr, error_action, red_fixed, green_fixed);
+}
+#endif
+
+void PNGAPI
+png_set_rgb_to_gray_fixed(png_structp png_ptr, int error_action,
+   png_fixed_point red, png_fixed_point green)
+{
+   png_debug(1, "in png_set_rgb_to_gray\n");
+   if(png_ptr == NULL) return;
+   switch(error_action)
+   {
+      case 1: png_ptr->transformations |= PNG_RGB_TO_GRAY;
+              break;
+      case 2: png_ptr->transformations |= PNG_RGB_TO_GRAY_WARN;
+              break;
+      case 3: png_ptr->transformations |= PNG_RGB_TO_GRAY_ERR;
+   }
+   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+#if defined(PNG_READ_EXPAND_SUPPORTED)
+      png_ptr->transformations |= PNG_EXPAND;
+#else
+   {
+      png_warning(png_ptr, "Cannot do RGB_TO_GRAY without EXPAND_SUPPORTED.");
+      png_ptr->transformations &= ~PNG_RGB_TO_GRAY;
+   }
+#endif
+   {
+      png_uint_16 red_int, green_int;
+      if(red < 0 || green < 0)
+      {
+         red_int   =  6968; /* .212671 * 32768 + .5 */
+         green_int = 23434; /* .715160 * 32768 + .5 */
+      }
+      else if(red + green < 100000L)
+      {
+        red_int = (png_uint_16)(((png_uint_32)red*32768L)/100000L);
+        green_int = (png_uint_16)(((png_uint_32)green*32768L)/100000L);
+      }
+      else
+      {
+         png_warning(png_ptr, "ignoring out of range rgb_to_gray coefficients");
+         red_int   =  6968;
+         green_int = 23434;
+      }
+      png_ptr->rgb_to_gray_red_coeff   = red_int;
+      png_ptr->rgb_to_gray_green_coeff = green_int;
+      png_ptr->rgb_to_gray_blue_coeff  = (png_uint_16)(32768-red_int-green_int);
+   }
+}
+#endif
+
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
+    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) || \
+    defined(PNG_LEGACY_SUPPORTED)
+void PNGAPI
+png_set_read_user_transform_fn(png_structp png_ptr, png_user_transform_ptr
+   read_user_transform_fn)
+{
+   png_debug(1, "in png_set_read_user_transform_fn\n");
+   if(png_ptr == NULL) return;
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
+   png_ptr->transformations |= PNG_USER_TRANSFORM;
+   png_ptr->read_user_transform_fn = read_user_transform_fn;
+#endif
+#ifdef PNG_LEGACY_SUPPORTED
+   if(read_user_transform_fn)
+      png_warning(png_ptr,
+        "This version of libpng does not support user transforms");
+#endif
+}
+#endif
+
+/* Initialize everything needed for the read.  This includes modifying
+ * the palette.
+ */
+void /* PRIVATE */
+png_init_read_transformations(png_structp png_ptr)
+{
+   png_debug(1, "in png_init_read_transformations\n");
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+   if(png_ptr != NULL)
+#endif
+  {
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) || defined(PNG_READ_SHIFT_SUPPORTED) \
+ || defined(PNG_READ_GAMMA_SUPPORTED)
+   int color_type = png_ptr->color_type;
+#endif
+
+#if defined(PNG_READ_EXPAND_SUPPORTED) && defined(PNG_READ_BACKGROUND_SUPPORTED)
+
+#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
+   /* Detect gray background and attempt to enable optimization
+    * for gray --> RGB case */
+   /* Note:  if PNG_BACKGROUND_EXPAND is set and color_type is either RGB or
+    * RGB_ALPHA (in which case need_expand is superfluous anyway), the
+    * background color might actually be gray yet not be flagged as such.
+    * This is not a problem for the current code, which uses
+    * PNG_BACKGROUND_IS_GRAY only to decide when to do the
+    * png_do_gray_to_rgb() transformation.
+    */
+   if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
+       !(color_type & PNG_COLOR_MASK_COLOR))
+   {
+          png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
+   } else if ((png_ptr->transformations & PNG_BACKGROUND) &&
+              !(png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
+              (png_ptr->transformations & PNG_GRAY_TO_RGB) &&
+              png_ptr->background.red == png_ptr->background.green &&
+              png_ptr->background.red == png_ptr->background.blue)
+   {
+          png_ptr->mode |= PNG_BACKGROUND_IS_GRAY;
+          png_ptr->background.gray = png_ptr->background.red;
+   }
+#endif
+
+   if ((png_ptr->transformations & PNG_BACKGROUND_EXPAND) &&
+       (png_ptr->transformations & PNG_EXPAND))
+   {
+      if (!(color_type & PNG_COLOR_MASK_COLOR))  /* i.e., GRAY or GRAY_ALPHA */
+      {
+         /* expand background and tRNS chunks */
+         switch (png_ptr->bit_depth)
+         {
+            case 1:
+               png_ptr->background.gray *= (png_uint_16)0xff;
+               png_ptr->background.red = png_ptr->background.green
+                 =  png_ptr->background.blue = png_ptr->background.gray;
+               if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
+               {
+                 png_ptr->trans_values.gray *= (png_uint_16)0xff;
+                 png_ptr->trans_values.red = png_ptr->trans_values.green
+                   = png_ptr->trans_values.blue = png_ptr->trans_values.gray;
+               }
+               break;
+            case 2:
+               png_ptr->background.gray *= (png_uint_16)0x55;
+               png_ptr->background.red = png_ptr->background.green
+                 = png_ptr->background.blue = png_ptr->background.gray;
+               if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
+               {
+                 png_ptr->trans_values.gray *= (png_uint_16)0x55;
+                 png_ptr->trans_values.red = png_ptr->trans_values.green
+                   = png_ptr->trans_values.blue = png_ptr->trans_values.gray;
+               }
+               break;
+            case 4:
+               png_ptr->background.gray *= (png_uint_16)0x11;
+               png_ptr->background.red = png_ptr->background.green
+                 = png_ptr->background.blue = png_ptr->background.gray;
+               if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
+               {
+                 png_ptr->trans_values.gray *= (png_uint_16)0x11;
+                 png_ptr->trans_values.red = png_ptr->trans_values.green
+                   = png_ptr->trans_values.blue = png_ptr->trans_values.gray;
+               }
+               break;
+            case 8:
+            case 16:
+               png_ptr->background.red = png_ptr->background.green
+                 = png_ptr->background.blue = png_ptr->background.gray;
+               break;
+         }
+      }
+      else if (color_type == PNG_COLOR_TYPE_PALETTE)
+      {
+         png_ptr->background.red   =
+            png_ptr->palette[png_ptr->background.index].red;
+         png_ptr->background.green =
+            png_ptr->palette[png_ptr->background.index].green;
+         png_ptr->background.blue  =
+            png_ptr->palette[png_ptr->background.index].blue;
+
+#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED)
+        if (png_ptr->transformations & PNG_INVERT_ALPHA)
+        {
+#if defined(PNG_READ_EXPAND_SUPPORTED)
+           if (!(png_ptr->transformations & PNG_EXPAND_tRNS))
+#endif
+           {
+           /* invert the alpha channel (in tRNS) unless the pixels are
+              going to be expanded, in which case leave it for later */
+              int i,istop;
+              istop=(int)png_ptr->num_trans;
+              for (i=0; i<istop; i++)
+                 png_ptr->trans[i] = (png_byte)(255 - png_ptr->trans[i]);
+           }
+        }
+#endif
+
+      }
+   }
+#endif
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) && defined(PNG_READ_GAMMA_SUPPORTED)
+   png_ptr->background_1 = png_ptr->background;
+#endif
+#if defined(PNG_READ_GAMMA_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED)
+
+   if ((color_type == PNG_COLOR_TYPE_PALETTE && png_ptr->num_trans != 0)
+       && (fabs(png_ptr->screen_gamma * png_ptr->gamma - 1.0)
+         < PNG_GAMMA_THRESHOLD))
+   {
+    int i,k;
+    k=0;
+    for (i=0; i<png_ptr->num_trans; i++)
+    {
+      if (png_ptr->trans[i] != 0 && png_ptr->trans[i] != 0xff)
+        k=1; /* partial transparency is present */
+    }
+    if (k == 0)
+      png_ptr->transformations &= (~PNG_GAMMA);
+   }
+
+   if ((png_ptr->transformations & (PNG_GAMMA | PNG_RGB_TO_GRAY)) &&
+        png_ptr->gamma != 0.0)
+   {
+      png_build_gamma_table(png_ptr);
+#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+      if (png_ptr->transformations & PNG_BACKGROUND)
+      {
+         if (color_type == PNG_COLOR_TYPE_PALETTE)
+         {
+           /* could skip if no transparency and
+           */
+            png_color back, back_1;
+            png_colorp palette = png_ptr->palette;
+            int num_palette = png_ptr->num_palette;
+            int i;
+            if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_FILE)
+            {
+               back.red = png_ptr->gamma_table[png_ptr->background.red];
+               back.green = png_ptr->gamma_table[png_ptr->background.green];
+               back.blue = png_ptr->gamma_table[png_ptr->background.blue];
+
+               back_1.red = png_ptr->gamma_to_1[png_ptr->background.red];
+               back_1.green = png_ptr->gamma_to_1[png_ptr->background.green];
+               back_1.blue = png_ptr->gamma_to_1[png_ptr->background.blue];
+            }
+            else
+            {
+               double g, gs;
+
+               switch (png_ptr->background_gamma_type)
+               {
+                  case PNG_BACKGROUND_GAMMA_SCREEN:
+                     g = (png_ptr->screen_gamma);
+                     gs = 1.0;
+                     break;
+                  case PNG_BACKGROUND_GAMMA_FILE:
+                     g = 1.0 / (png_ptr->gamma);
+                     gs = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);
+                     break;
+                  case PNG_BACKGROUND_GAMMA_UNIQUE:
+                     g = 1.0 / (png_ptr->background_gamma);
+                     gs = 1.0 / (png_ptr->background_gamma *
+                                 png_ptr->screen_gamma);
+                     break;
+                  default:
+                     g = 1.0;    /* back_1 */
+                     gs = 1.0;   /* back */
+               }
+
+               if ( fabs(gs - 1.0) < PNG_GAMMA_THRESHOLD)
+               {
+                  back.red   = (png_byte)png_ptr->background.red;
+                  back.green = (png_byte)png_ptr->background.green;
+                  back.blue  = (png_byte)png_ptr->background.blue;
+               }
+               else
+               {
+                  back.red = (png_byte)(pow(
+                     (double)png_ptr->background.red/255, gs) * 255.0 + .5);
+                  back.green = (png_byte)(pow(
+                     (double)png_ptr->background.green/255, gs) * 255.0 + .5);
+                  back.blue = (png_byte)(pow(
+                     (double)png_ptr->background.blue/255, gs) * 255.0 + .5);
+               }
+
+               back_1.red = (png_byte)(pow(
+                  (double)png_ptr->background.red/255, g) * 255.0 + .5);
+               back_1.green = (png_byte)(pow(
+                  (double)png_ptr->background.green/255, g) * 255.0 + .5);
+               back_1.blue = (png_byte)(pow(
+                  (double)png_ptr->background.blue/255, g) * 255.0 + .5);
+            }
+            for (i = 0; i < num_palette; i++)
+            {
+               if (i < (int)png_ptr->num_trans && png_ptr->trans[i] != 0xff)
+               {
+                  if (png_ptr->trans[i] == 0)
+                  {
+                     palette[i] = back;
+                  }
+                  else /* if (png_ptr->trans[i] != 0xff) */
+                  {
+                     png_byte v, w;
+
+                     v = png_ptr->gamma_to_1[palette[i].red];
+                     png_composite(w, v, png_ptr->trans[i], back_1.red);
+                     palette[i].red = png_ptr->gamma_from_1[w];
+
+                     v = png_ptr->gamma_to_1[palette[i].green];
+                     png_composite(w, v, png_ptr->trans[i], back_1.green);
+                     palette[i].green = png_ptr->gamma_from_1[w];
+
+                     v = png_ptr->gamma_to_1[palette[i].blue];
+                     png_composite(w, v, png_ptr->trans[i], back_1.blue);
+                     palette[i].blue = png_ptr->gamma_from_1[w];
+                  }
+               }
+               else
+               {
+                  palette[i].red = png_ptr->gamma_table[palette[i].red];
+                  palette[i].green = png_ptr->gamma_table[palette[i].green];
+                  palette[i].blue = png_ptr->gamma_table[palette[i].blue];
+               }
+            }
+         }
+         /* if (png_ptr->background_gamma_type!=PNG_BACKGROUND_GAMMA_UNKNOWN) */
+         else
+         /* color_type != PNG_COLOR_TYPE_PALETTE */
+         {
+            double m = (double)(((png_uint_32)1 << png_ptr->bit_depth) - 1);
+            double g = 1.0;
+            double gs = 1.0;
+
+            switch (png_ptr->background_gamma_type)
+            {
+               case PNG_BACKGROUND_GAMMA_SCREEN:
+                  g = (png_ptr->screen_gamma);
+                  gs = 1.0;
+                  break;
+               case PNG_BACKGROUND_GAMMA_FILE:
+                  g = 1.0 / (png_ptr->gamma);
+                  gs = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);
+                  break;
+               case PNG_BACKGROUND_GAMMA_UNIQUE:
+                  g = 1.0 / (png_ptr->background_gamma);
+                  gs = 1.0 / (png_ptr->background_gamma *
+                     png_ptr->screen_gamma);
+                  break;
+            }
+
+            png_ptr->background_1.gray = (png_uint_16)(pow(
+               (double)png_ptr->background.gray / m, g) * m + .5);
+            png_ptr->background.gray = (png_uint_16)(pow(
+               (double)png_ptr->background.gray / m, gs) * m + .5);
+
+            if ((png_ptr->background.red != png_ptr->background.green) ||
+                (png_ptr->background.red != png_ptr->background.blue) ||
+                (png_ptr->background.red != png_ptr->background.gray))
+            {
+               /* RGB or RGBA with color background */
+               png_ptr->background_1.red = (png_uint_16)(pow(
+                  (double)png_ptr->background.red / m, g) * m + .5);
+               png_ptr->background_1.green = (png_uint_16)(pow(
+                  (double)png_ptr->background.green / m, g) * m + .5);
+               png_ptr->background_1.blue = (png_uint_16)(pow(
+                  (double)png_ptr->background.blue / m, g) * m + .5);
+               png_ptr->background.red = (png_uint_16)(pow(
+                  (double)png_ptr->background.red / m, gs) * m + .5);
+               png_ptr->background.green = (png_uint_16)(pow(
+                  (double)png_ptr->background.green / m, gs) * m + .5);
+               png_ptr->background.blue = (png_uint_16)(pow(
+                  (double)png_ptr->background.blue / m, gs) * m + .5);
+            }
+            else
+            {
+               /* GRAY, GRAY ALPHA, RGB, or RGBA with gray background */
+               png_ptr->background_1.red = png_ptr->background_1.green
+                 = png_ptr->background_1.blue = png_ptr->background_1.gray;
+               png_ptr->background.red = png_ptr->background.green
+                 = png_ptr->background.blue = png_ptr->background.gray;
+            }
+         }
+      }
+      else
+      /* transformation does not include PNG_BACKGROUND */
+#endif /* PNG_READ_BACKGROUND_SUPPORTED */
+      if (color_type == PNG_COLOR_TYPE_PALETTE)
+      {
+         png_colorp palette = png_ptr->palette;
+         int num_palette = png_ptr->num_palette;
+         int i;
+
+         for (i = 0; i < num_palette; i++)
+         {
+            palette[i].red = png_ptr->gamma_table[palette[i].red];
+            palette[i].green = png_ptr->gamma_table[palette[i].green];
+            palette[i].blue = png_ptr->gamma_table[palette[i].blue];
+         }
+      }
+   }
+#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+   else
+#endif
+#endif /* PNG_READ_GAMMA_SUPPORTED && PNG_FLOATING_POINT_SUPPORTED */
+#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+   /* No GAMMA transformation */
+   if ((png_ptr->transformations & PNG_BACKGROUND) &&
+       (color_type == PNG_COLOR_TYPE_PALETTE))
+   {
+      int i;
+      int istop = (int)png_ptr->num_trans;
+      png_color back;
+      png_colorp palette = png_ptr->palette;
+
+      back.red   = (png_byte)png_ptr->background.red;
+      back.green = (png_byte)png_ptr->background.green;
+      back.blue  = (png_byte)png_ptr->background.blue;
+
+      for (i = 0; i < istop; i++)
+      {
+         if (png_ptr->trans[i] == 0)
+         {
+            palette[i] = back;
+         }
+         else if (png_ptr->trans[i] != 0xff)
+         {
+            /* The png_composite() macro is defined in png.h */
+            png_composite(palette[i].red, palette[i].red,
+               png_ptr->trans[i], back.red);
+            png_composite(palette[i].green, palette[i].green,
+               png_ptr->trans[i], back.green);
+            png_composite(palette[i].blue, palette[i].blue,
+               png_ptr->trans[i], back.blue);
+         }
+      }
+   }
+#endif /* PNG_READ_BACKGROUND_SUPPORTED */
+
+#if defined(PNG_READ_SHIFT_SUPPORTED)
+   if ((png_ptr->transformations & PNG_SHIFT) &&
+      (color_type == PNG_COLOR_TYPE_PALETTE))
+   {
+      png_uint_16 i;
+      png_uint_16 istop = png_ptr->num_palette;
+      int sr = 8 - png_ptr->sig_bit.red;
+      int sg = 8 - png_ptr->sig_bit.green;
+      int sb = 8 - png_ptr->sig_bit.blue;
+
+      if (sr < 0 || sr > 8)
+         sr = 0;
+      if (sg < 0 || sg > 8)
+         sg = 0;
+      if (sb < 0 || sb > 8)
+         sb = 0;
+      for (i = 0; i < istop; i++)
+      {
+         png_ptr->palette[i].red >>= sr;
+         png_ptr->palette[i].green >>= sg;
+         png_ptr->palette[i].blue >>= sb;
+      }
+   }
+#endif  /* PNG_READ_SHIFT_SUPPORTED */
+ }
+#if !defined(PNG_READ_GAMMA_SUPPORTED) && !defined(PNG_READ_SHIFT_SUPPORTED) \
+ && !defined(PNG_READ_BACKGROUND_SUPPORTED)
+   if(png_ptr)
+      return;
+#endif
+}
+
+/* Modify the info structure to reflect the transformations.  The
+ * info should be updated so a PNG file could be written with it,
+ * assuming the transformations result in valid PNG data.
+ */
+void /* PRIVATE */
+png_read_transform_info(png_structp png_ptr, png_infop info_ptr)
+{
+   png_debug(1, "in png_read_transform_info\n");
+#if defined(PNG_READ_EXPAND_SUPPORTED)
+   if (png_ptr->transformations & PNG_EXPAND)
+   {
+      if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      {
+         if (png_ptr->num_trans && (png_ptr->transformations & PNG_EXPAND_tRNS))
+            info_ptr->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
+         else
+            info_ptr->color_type = PNG_COLOR_TYPE_RGB;
+         info_ptr->bit_depth = 8;
+         info_ptr->num_trans = 0;
+      }
+      else
+      {
+         if (png_ptr->num_trans)
+         {
+            if (png_ptr->transformations & PNG_EXPAND_tRNS)
+              info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
+            else
+              info_ptr->color_type |= PNG_COLOR_MASK_COLOR;
+         }
+         if (info_ptr->bit_depth < 8)
+            info_ptr->bit_depth = 8;
+         info_ptr->num_trans = 0;
+      }
+   }
+#endif
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+   if (png_ptr->transformations & PNG_BACKGROUND)
+   {
+      info_ptr->color_type &= ~PNG_COLOR_MASK_ALPHA;
+      info_ptr->num_trans = 0;
+      info_ptr->background = png_ptr->background;
+   }
+#endif
+
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+   if (png_ptr->transformations & PNG_GAMMA)
+   {
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+      info_ptr->gamma = png_ptr->gamma;
+#endif
+#ifdef PNG_FIXED_POINT_SUPPORTED
+      info_ptr->int_gamma = png_ptr->int_gamma;
+#endif
+   }
+#endif
+
+#if defined(PNG_READ_16_TO_8_SUPPORTED)
+   if ((png_ptr->transformations & PNG_16_TO_8) && (info_ptr->bit_depth == 16))
+      info_ptr->bit_depth = 8;
+#endif
+
+#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
+   if (png_ptr->transformations & PNG_GRAY_TO_RGB)
+      info_ptr->color_type |= PNG_COLOR_MASK_COLOR;
+#endif
+
+#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+   if (png_ptr->transformations & PNG_RGB_TO_GRAY)
+      info_ptr->color_type &= ~PNG_COLOR_MASK_COLOR;
+#endif
+
+#if defined(PNG_READ_DITHER_SUPPORTED)
+   if (png_ptr->transformations & PNG_DITHER)
+   {
+      if (((info_ptr->color_type == PNG_COLOR_TYPE_RGB) ||
+         (info_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)) &&
+         png_ptr->palette_lookup && info_ptr->bit_depth == 8)
+      {
+         info_ptr->color_type = PNG_COLOR_TYPE_PALETTE;
+      }
+   }
+#endif
+
+#if defined(PNG_READ_PACK_SUPPORTED)
+   if ((png_ptr->transformations & PNG_PACK) && (info_ptr->bit_depth < 8))
+      info_ptr->bit_depth = 8;
+#endif
+
+   if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      info_ptr->channels = 1;
+   else if (info_ptr->color_type & PNG_COLOR_MASK_COLOR)
+      info_ptr->channels = 3;
+   else
+      info_ptr->channels = 1;
+
+#if defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
+   if (png_ptr->flags & PNG_FLAG_STRIP_ALPHA)
+      info_ptr->color_type &= ~PNG_COLOR_MASK_ALPHA;
+#endif
+
+   if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
+      info_ptr->channels++;
+
+#if defined(PNG_READ_FILLER_SUPPORTED)
+   /* STRIP_ALPHA and FILLER allowed:  MASK_ALPHA bit stripped above */
+   if ((png_ptr->transformations & PNG_FILLER) &&
+       ((info_ptr->color_type == PNG_COLOR_TYPE_RGB) ||
+       (info_ptr->color_type == PNG_COLOR_TYPE_GRAY)))
+   {
+      info_ptr->channels++;
+      /* if adding a true alpha channel not just filler */
+#if !defined(PNG_1_0_X)
+      if (png_ptr->transformations & PNG_ADD_ALPHA)
+        info_ptr->color_type |= PNG_COLOR_MASK_ALPHA;
+#endif
+   }
+#endif
+
+#if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED) && \
+defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
+   if(png_ptr->transformations & PNG_USER_TRANSFORM)
+     {
+       if(info_ptr->bit_depth < png_ptr->user_transform_depth)
+         info_ptr->bit_depth = png_ptr->user_transform_depth;
+       if(info_ptr->channels < png_ptr->user_transform_channels)
+         info_ptr->channels = png_ptr->user_transform_channels;
+     }
+#endif
+
+   info_ptr->pixel_depth = (png_byte)(info_ptr->channels *
+      info_ptr->bit_depth);
+
+   info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth,info_ptr->width);
+
+#if !defined(PNG_READ_EXPAND_SUPPORTED)
+   if(png_ptr)
+      return;
+#endif
+}
+
+/* Transform the row.  The order of transformations is significant,
+ * and is very touchy.  If you add a transformation, take care to
+ * decide how it fits in with the other transformations here.
+ */
+void /* PRIVATE */
+png_do_read_transformations(png_structp png_ptr)
+{
+   png_debug(1, "in png_do_read_transformations\n");
+   if (png_ptr->row_buf == NULL)
+   {
+#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
+      char msg[50];
+
+      png_snprintf2(msg, 50,
+         "NULL row buffer for row %ld, pass %d", png_ptr->row_number,
+         png_ptr->pass);
+      png_error(png_ptr, msg);
+#else
+      png_error(png_ptr, "NULL row buffer");
+#endif
+   }
+#ifdef PNG_WARN_UNINITIALIZED_ROW
+   if (!(png_ptr->flags & PNG_FLAG_ROW_INIT))
+      /* Application has failed to call either png_read_start_image()
+       * or png_read_update_info() after setting transforms that expand
+       * pixels.  This check added to libpng-1.2.19 */
+#if (PNG_WARN_UNINITIALIZED_ROW==1)
+      png_error(png_ptr, "Uninitialized row");
+#else
+      png_warning(png_ptr, "Uninitialized row");
+#endif
+#endif
+
+#if defined(PNG_READ_EXPAND_SUPPORTED)
+   if (png_ptr->transformations & PNG_EXPAND)
+   {
+      if (png_ptr->row_info.color_type == PNG_COLOR_TYPE_PALETTE)
+      {
+         png_do_expand_palette(&(png_ptr->row_info), png_ptr->row_buf + 1,
+            png_ptr->palette, png_ptr->trans, png_ptr->num_trans);
+      }
+      else
+      {
+         if (png_ptr->num_trans &&
+             (png_ptr->transformations & PNG_EXPAND_tRNS))
+            png_do_expand(&(png_ptr->row_info), png_ptr->row_buf + 1,
+               &(png_ptr->trans_values));
+         else
+            png_do_expand(&(png_ptr->row_info), png_ptr->row_buf + 1,
+               NULL);
+      }
+   }
+#endif
+
+#if defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
+   if (png_ptr->flags & PNG_FLAG_STRIP_ALPHA)
+      png_do_strip_filler(&(png_ptr->row_info), png_ptr->row_buf + 1,
+         PNG_FLAG_FILLER_AFTER | (png_ptr->flags & PNG_FLAG_STRIP_ALPHA));
+#endif
+
+#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+   if (png_ptr->transformations & PNG_RGB_TO_GRAY)
+   {
+      int rgb_error =
+         png_do_rgb_to_gray(png_ptr, &(png_ptr->row_info), png_ptr->row_buf + 1);
+      if(rgb_error)
+      {
+         png_ptr->rgb_to_gray_status=1;
+         if((png_ptr->transformations & PNG_RGB_TO_GRAY) == 
+             PNG_RGB_TO_GRAY_WARN)
+            png_warning(png_ptr, "png_do_rgb_to_gray found nongray pixel");
+         if((png_ptr->transformations & PNG_RGB_TO_GRAY) ==
+             PNG_RGB_TO_GRAY_ERR)
+            png_error(png_ptr, "png_do_rgb_to_gray found nongray pixel");
+      }
+   }
+#endif
+
+/*
+From Andreas Dilger e-mail to png-implement, 26 March 1998:
+
+  In most cases, the "simple transparency" should be done prior to doing
+  gray-to-RGB, or you will have to test 3x as many bytes to check if a
+  pixel is transparent.  You would also need to make sure that the
+  transparency information is upgraded to RGB.
+
+  To summarize, the current flow is:
+  - Gray + simple transparency -> compare 1 or 2 gray bytes and composite
+                                  with background "in place" if transparent,
+                                  convert to RGB if necessary
+  - Gray + alpha -> composite with gray background and remove alpha bytes,
+                                  convert to RGB if necessary
+
+  To support RGB backgrounds for gray images we need:
+  - Gray + simple transparency -> convert to RGB + simple transparency, compare
+                                  3 or 6 bytes and composite with background
+                                  "in place" if transparent (3x compare/pixel
+                                  compared to doing composite with gray bkgrnd)
+  - Gray + alpha -> convert to RGB + alpha, composite with background and
+                                  remove alpha bytes (3x float operations/pixel
+                                  compared with composite on gray background)
+
+  Greg's change will do this.  The reason it wasn't done before is for
+  performance, as this increases the per-pixel operations.  If we would check
+  in advance if the background was gray or RGB, and position the gray-to-RGB
+  transform appropriately, then it would save a lot of work/time.
+ */
+
+#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
+   /* if gray -> RGB, do so now only if background is non-gray; else do later
+    * for performance reasons */
+   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
+       !(png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
+      png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+   if ((png_ptr->transformations & PNG_BACKGROUND) &&
+      ((png_ptr->num_trans != 0 ) ||
+      (png_ptr->color_type & PNG_COLOR_MASK_ALPHA)))
+      png_do_background(&(png_ptr->row_info), png_ptr->row_buf + 1,
+         &(png_ptr->trans_values), &(png_ptr->background)
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+         , &(png_ptr->background_1),
+         png_ptr->gamma_table, png_ptr->gamma_from_1,
+         png_ptr->gamma_to_1, png_ptr->gamma_16_table,
+         png_ptr->gamma_16_from_1, png_ptr->gamma_16_to_1,
+         png_ptr->gamma_shift
+#endif
+);
+#endif
+
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+   if ((png_ptr->transformations & PNG_GAMMA) &&
+#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+      !((png_ptr->transformations & PNG_BACKGROUND) &&
+      ((png_ptr->num_trans != 0) ||
+      (png_ptr->color_type & PNG_COLOR_MASK_ALPHA))) &&
+#endif
+      (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE))
+      png_do_gamma(&(png_ptr->row_info), png_ptr->row_buf + 1,
+         png_ptr->gamma_table, png_ptr->gamma_16_table,
+         png_ptr->gamma_shift);
+#endif
+
+#if defined(PNG_READ_16_TO_8_SUPPORTED)
+   if (png_ptr->transformations & PNG_16_TO_8)
+      png_do_chop(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+
+#if defined(PNG_READ_DITHER_SUPPORTED)
+   if (png_ptr->transformations & PNG_DITHER)
+   {
+      png_do_dither((png_row_infop)&(png_ptr->row_info), png_ptr->row_buf + 1,
+         png_ptr->palette_lookup, png_ptr->dither_index);
+      if(png_ptr->row_info.rowbytes == (png_uint_32)0)
+         png_error(png_ptr, "png_do_dither returned rowbytes=0");
+   }
+#endif
+
+#if defined(PNG_READ_INVERT_SUPPORTED)
+   if (png_ptr->transformations & PNG_INVERT_MONO)
+      png_do_invert(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+
+#if defined(PNG_READ_SHIFT_SUPPORTED)
+   if (png_ptr->transformations & PNG_SHIFT)
+      png_do_unshift(&(png_ptr->row_info), png_ptr->row_buf + 1,
+         &(png_ptr->shift));
+#endif
+
+#if defined(PNG_READ_PACK_SUPPORTED)
+   if (png_ptr->transformations & PNG_PACK)
+      png_do_unpack(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+
+#if defined(PNG_READ_BGR_SUPPORTED)
+   if (png_ptr->transformations & PNG_BGR)
+      png_do_bgr(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+   if (png_ptr->transformations & PNG_PACKSWAP)
+      png_do_packswap(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+
+#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
+   /* if gray -> RGB, do so now only if we did not do so above */
+   if ((png_ptr->transformations & PNG_GRAY_TO_RGB) &&
+       (png_ptr->mode & PNG_BACKGROUND_IS_GRAY))
+      png_do_gray_to_rgb(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+
+#if defined(PNG_READ_FILLER_SUPPORTED)
+   if (png_ptr->transformations & PNG_FILLER)
+      png_do_read_filler(&(png_ptr->row_info), png_ptr->row_buf + 1,
+         (png_uint_32)png_ptr->filler, png_ptr->flags);
+#endif
+
+#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED)
+   if (png_ptr->transformations & PNG_INVERT_ALPHA)
+      png_do_read_invert_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+
+#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED)
+   if (png_ptr->transformations & PNG_SWAP_ALPHA)
+      png_do_read_swap_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+
+#if defined(PNG_READ_SWAP_SUPPORTED)
+   if (png_ptr->transformations & PNG_SWAP_BYTES)
+      png_do_swap(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED)
+   if (png_ptr->transformations & PNG_USER_TRANSFORM)
+    {
+      if(png_ptr->read_user_transform_fn != NULL)
+        (*(png_ptr->read_user_transform_fn)) /* user read transform function */
+          (png_ptr,                    /* png_ptr */
+           &(png_ptr->row_info),       /* row_info:     */
+             /*  png_uint_32 width;          width of row */
+             /*  png_uint_32 rowbytes;       number of bytes in row */
+             /*  png_byte color_type;        color type of pixels */
+             /*  png_byte bit_depth;         bit depth of samples */
+             /*  png_byte channels;          number of channels (1-4) */
+             /*  png_byte pixel_depth;       bits per pixel (depth*channels) */
+           png_ptr->row_buf + 1);      /* start of pixel data for row */
+#if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
+      if(png_ptr->user_transform_depth)
+         png_ptr->row_info.bit_depth = png_ptr->user_transform_depth;
+      if(png_ptr->user_transform_channels)
+         png_ptr->row_info.channels = png_ptr->user_transform_channels;
+#endif
+      png_ptr->row_info.pixel_depth = (png_byte)(png_ptr->row_info.bit_depth *
+         png_ptr->row_info.channels);
+      png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
+         png_ptr->row_info.width);
+   }
+#endif
+
+}
+
+#if defined(PNG_READ_PACK_SUPPORTED)
+/* Unpack pixels of 1, 2, or 4 bits per pixel into 1 byte per pixel,
+ * without changing the actual values.  Thus, if you had a row with
+ * a bit depth of 1, you would end up with bytes that only contained
+ * the numbers 0 or 1.  If you would rather they contain 0 and 255, use
+ * png_do_shift() after this.
+ */
+void /* PRIVATE */
+png_do_unpack(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_unpack\n");
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+   if (row != NULL && row_info != NULL && row_info->bit_depth < 8)
+#else
+   if (row_info->bit_depth < 8)
+#endif
+   {
+      png_uint_32 i;
+      png_uint_32 row_width=row_info->width;
+
+      switch (row_info->bit_depth)
+      {
+         case 1:
+         {
+            png_bytep sp = row + (png_size_t)((row_width - 1) >> 3);
+            png_bytep dp = row + (png_size_t)row_width - 1;
+            png_uint_32 shift = 7 - (int)((row_width + 7) & 0x07);
+            for (i = 0; i < row_width; i++)
+            {
+               *dp = (png_byte)((*sp >> shift) & 0x01);
+               if (shift == 7)
+               {
+                  shift = 0;
+                  sp--;
+               }
+               else
+                  shift++;
+
+               dp--;
+            }
+            break;
+         }
+         case 2:
+         {
+
+            png_bytep sp = row + (png_size_t)((row_width - 1) >> 2);
+            png_bytep dp = row + (png_size_t)row_width - 1;
+            png_uint_32 shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
+            for (i = 0; i < row_width; i++)
+            {
+               *dp = (png_byte)((*sp >> shift) & 0x03);
+               if (shift == 6)
+               {
+                  shift = 0;
+                  sp--;
+               }
+               else
+                  shift += 2;
+
+               dp--;
+            }
+            break;
+         }
+         case 4:
+         {
+            png_bytep sp = row + (png_size_t)((row_width - 1) >> 1);
+            png_bytep dp = row + (png_size_t)row_width - 1;
+            png_uint_32 shift = (int)((1 - ((row_width + 1) & 0x01)) << 2);
+            for (i = 0; i < row_width; i++)
+            {
+               *dp = (png_byte)((*sp >> shift) & 0x0f);
+               if (shift == 4)
+               {
+                  shift = 0;
+                  sp--;
+               }
+               else
+                  shift = 4;
+
+               dp--;
+            }
+            break;
+         }
+      }
+      row_info->bit_depth = 8;
+      row_info->pixel_depth = (png_byte)(8 * row_info->channels);
+      row_info->rowbytes = row_width * row_info->channels;
+   }
+}
+#endif
+
+#if defined(PNG_READ_SHIFT_SUPPORTED)
+/* Reverse the effects of png_do_shift.  This routine merely shifts the
+ * pixels back to their significant bits values.  Thus, if you have
+ * a row of bit depth 8, but only 5 are significant, this will shift
+ * the values back to 0 through 31.
+ */
+void /* PRIVATE */
+png_do_unshift(png_row_infop row_info, png_bytep row, png_color_8p sig_bits)
+{
+   png_debug(1, "in png_do_unshift\n");
+   if (
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+       row != NULL && row_info != NULL && sig_bits != NULL &&
+#endif
+       row_info->color_type != PNG_COLOR_TYPE_PALETTE)
+   {
+      int shift[4];
+      int channels = 0;
+      int c;
+      png_uint_16 value = 0;
+      png_uint_32 row_width = row_info->width;
+
+      if (row_info->color_type & PNG_COLOR_MASK_COLOR)
+      {
+         shift[channels++] = row_info->bit_depth - sig_bits->red;
+         shift[channels++] = row_info->bit_depth - sig_bits->green;
+         shift[channels++] = row_info->bit_depth - sig_bits->blue;
+      }
+      else
+      {
+         shift[channels++] = row_info->bit_depth - sig_bits->gray;
+      }
+      if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
+      {
+         shift[channels++] = row_info->bit_depth - sig_bits->alpha;
+      }
+
+      for (c = 0; c < channels; c++)
+      {
+         if (shift[c] <= 0)
+            shift[c] = 0;
+         else
+            value = 1;
+      }
+
+      if (!value)
+         return;
+
+      switch (row_info->bit_depth)
+      {
+         case 2:
+         {
+            png_bytep bp;
+            png_uint_32 i;
+            png_uint_32 istop = row_info->rowbytes;
+
+            for (bp = row, i = 0; i < istop; i++)
+            {
+               *bp >>= 1;
+               *bp++ &= 0x55;
+            }
+            break;
+         }
+         case 4:
+         {
+            png_bytep bp = row;
+            png_uint_32 i;
+            png_uint_32 istop = row_info->rowbytes;
+            png_byte mask = (png_byte)((((int)0xf0 >> shift[0]) & (int)0xf0) |
+               (png_byte)((int)0xf >> shift[0]));
+
+            for (i = 0; i < istop; i++)
+            {
+               *bp >>= shift[0];
+               *bp++ &= mask;
+            }
+            break;
+         }
+         case 8:
+         {
+            png_bytep bp = row;
+            png_uint_32 i;
+            png_uint_32 istop = row_width * channels;
+
+            for (i = 0; i < istop; i++)
+            {
+               *bp++ >>= shift[i%channels];
+            }
+            break;
+         }
+         case 16:
+         {
+            png_bytep bp = row;
+            png_uint_32 i;
+            png_uint_32 istop = channels * row_width;
+
+            for (i = 0; i < istop; i++)
+            {
+               value = (png_uint_16)((*bp << 8) + *(bp + 1));
+               value >>= shift[i%channels];
+               *bp++ = (png_byte)(value >> 8);
+               *bp++ = (png_byte)(value & 0xff);
+            }
+            break;
+         }
+      }
+   }
+}
+#endif
+
+#if defined(PNG_READ_16_TO_8_SUPPORTED)
+/* chop rows of bit depth 16 down to 8 */
+void /* PRIVATE */
+png_do_chop(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_chop\n");
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+   if (row != NULL && row_info != NULL && row_info->bit_depth == 16)
+#else
+   if (row_info->bit_depth == 16)
+#endif
+   {
+      png_bytep sp = row;
+      png_bytep dp = row;
+      png_uint_32 i;
+      png_uint_32 istop = row_info->width * row_info->channels;
+
+      for (i = 0; i<istop; i++, sp += 2, dp++)
+      {
+#if defined(PNG_READ_16_TO_8_ACCURATE_SCALE_SUPPORTED)
+      /* This does a more accurate scaling of the 16-bit color
+       * value, rather than a simple low-byte truncation.
+       *
+       * What the ideal calculation should be:
+       *   *dp = (((((png_uint_32)(*sp) << 8) |
+       *          (png_uint_32)(*(sp + 1))) * 255 + 127) / (png_uint_32)65535L;
+       *
+       * GRR: no, I think this is what it really should be:
+       *   *dp = (((((png_uint_32)(*sp) << 8) |
+       *           (png_uint_32)(*(sp + 1))) + 128L) / (png_uint_32)257L;
+       *
+       * GRR: here's the exact calculation with shifts:
+       *   temp = (((png_uint_32)(*sp) << 8) | (png_uint_32)(*(sp + 1))) + 128L;
+       *   *dp = (temp - (temp >> 8)) >> 8;
+       *
+       * Approximate calculation with shift/add instead of multiply/divide:
+       *   *dp = ((((png_uint_32)(*sp) << 8) |
+       *          (png_uint_32)((int)(*(sp + 1)) - *sp)) + 128) >> 8;
+       *
+       * What we actually do to avoid extra shifting and conversion:
+       */
+
+         *dp = *sp + ((((int)(*(sp + 1)) - *sp) > 128) ? 1 : 0);
+#else
+       /* Simply discard the low order byte */
+         *dp = *sp;
+#endif
+      }
+      row_info->bit_depth = 8;
+      row_info->pixel_depth = (png_byte)(8 * row_info->channels);
+      row_info->rowbytes = row_info->width * row_info->channels;
+   }
+}
+#endif
+
+#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED)
+void /* PRIVATE */
+png_do_read_swap_alpha(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_read_swap_alpha\n");
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+   if (row != NULL && row_info != NULL)
+#endif
+   {
+      png_uint_32 row_width = row_info->width;
+      if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+      {
+         /* This converts from RGBA to ARGB */
+         if (row_info->bit_depth == 8)
+         {
+            png_bytep sp = row + row_info->rowbytes;
+            png_bytep dp = sp;
+            png_byte save;
+            png_uint_32 i;
+
+            for (i = 0; i < row_width; i++)
+            {
+               save = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = save;
+            }
+         }
+         /* This converts from RRGGBBAA to AARRGGBB */
+         else
+         {
+            png_bytep sp = row + row_info->rowbytes;
+            png_bytep dp = sp;
+            png_byte save[2];
+            png_uint_32 i;
+
+            for (i = 0; i < row_width; i++)
+            {
+               save[0] = *(--sp);
+               save[1] = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = save[0];
+               *(--dp) = save[1];
+            }
+         }
+      }
+      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      {
+         /* This converts from GA to AG */
+         if (row_info->bit_depth == 8)
+         {
+            png_bytep sp = row + row_info->rowbytes;
+            png_bytep dp = sp;
+            png_byte save;
+            png_uint_32 i;
+
+            for (i = 0; i < row_width; i++)
+            {
+               save = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = save;
+            }
+         }
+         /* This converts from GGAA to AAGG */
+         else
+         {
+            png_bytep sp = row + row_info->rowbytes;
+            png_bytep dp = sp;
+            png_byte save[2];
+            png_uint_32 i;
+
+            for (i = 0; i < row_width; i++)
+            {
+               save[0] = *(--sp);
+               save[1] = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = save[0];
+               *(--dp) = save[1];
+            }
+         }
+      }
+   }
+}
+#endif
+
+#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED)
+void /* PRIVATE */
+png_do_read_invert_alpha(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_read_invert_alpha\n");
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+   if (row != NULL && row_info != NULL)
+#endif
+   {
+      png_uint_32 row_width = row_info->width;
+      if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+      {
+         /* This inverts the alpha channel in RGBA */
+         if (row_info->bit_depth == 8)
+         {
+            png_bytep sp = row + row_info->rowbytes;
+            png_bytep dp = sp;
+            png_uint_32 i;
+
+            for (i = 0; i < row_width; i++)
+            {
+               *(--dp) = (png_byte)(255 - *(--sp));
+
+/*             This does nothing:
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               We can replace it with:
+*/
+               sp-=3;
+               dp=sp;
+            }
+         }
+         /* This inverts the alpha channel in RRGGBBAA */
+         else
+         {
+            png_bytep sp = row + row_info->rowbytes;
+            png_bytep dp = sp;
+            png_uint_32 i;
+
+            for (i = 0; i < row_width; i++)
+            {
+               *(--dp) = (png_byte)(255 - *(--sp));
+               *(--dp) = (png_byte)(255 - *(--sp));
+
+/*             This does nothing:
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               We can replace it with:
+*/
+               sp-=6;
+               dp=sp;
+            }
+         }
+      }
+      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      {
+         /* This inverts the alpha channel in GA */
+         if (row_info->bit_depth == 8)
+         {
+            png_bytep sp = row + row_info->rowbytes;
+            png_bytep dp = sp;
+            png_uint_32 i;
+
+            for (i = 0; i < row_width; i++)
+            {
+               *(--dp) = (png_byte)(255 - *(--sp));
+               *(--dp) = *(--sp);
+            }
+         }
+         /* This inverts the alpha channel in GGAA */
+         else
+         {
+            png_bytep sp  = row + row_info->rowbytes;
+            png_bytep dp = sp;
+            png_uint_32 i;
+
+            for (i = 0; i < row_width; i++)
+            {
+               *(--dp) = (png_byte)(255 - *(--sp));
+               *(--dp) = (png_byte)(255 - *(--sp));
+/*
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+*/
+               sp-=2;
+               dp=sp;
+            }
+         }
+      }
+   }
+}
+#endif
+
+#if defined(PNG_READ_FILLER_SUPPORTED)
+/* Add filler channel if we have RGB color */
+void /* PRIVATE */
+png_do_read_filler(png_row_infop row_info, png_bytep row,
+   png_uint_32 filler, png_uint_32 flags)
+{
+   png_uint_32 i;
+   png_uint_32 row_width = row_info->width;
+
+   png_byte hi_filler = (png_byte)((filler>>8) & 0xff);
+   png_byte lo_filler = (png_byte)(filler & 0xff);
+
+   png_debug(1, "in png_do_read_filler\n");
+   if (
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+       row != NULL  && row_info != NULL &&
+#endif
+       row_info->color_type == PNG_COLOR_TYPE_GRAY)
+   {
+      if(row_info->bit_depth == 8)
+      {
+         /* This changes the data from G to GX */
+         if (flags & PNG_FLAG_FILLER_AFTER)
+         {
+            png_bytep sp = row + (png_size_t)row_width;
+            png_bytep dp =  sp + (png_size_t)row_width;
+            for (i = 1; i < row_width; i++)
+            {
+               *(--dp) = lo_filler;
+               *(--dp) = *(--sp);
+            }
+            *(--dp) = lo_filler;
+            row_info->channels = 2;
+            row_info->pixel_depth = 16;
+            row_info->rowbytes = row_width * 2;
+         }
+      /* This changes the data from G to XG */
+         else
+         {
+            png_bytep sp = row + (png_size_t)row_width;
+            png_bytep dp = sp  + (png_size_t)row_width;
+            for (i = 0; i < row_width; i++)
+            {
+               *(--dp) = *(--sp);
+               *(--dp) = lo_filler;
+            }
+            row_info->channels = 2;
+            row_info->pixel_depth = 16;
+            row_info->rowbytes = row_width * 2;
+         }
+      }
+      else if(row_info->bit_depth == 16)
+      {
+         /* This changes the data from GG to GGXX */
+         if (flags & PNG_FLAG_FILLER_AFTER)
+         {
+            png_bytep sp = row + (png_size_t)row_width * 2;
+            png_bytep dp = sp  + (png_size_t)row_width * 2;
+            for (i = 1; i < row_width; i++)
+            {
+               *(--dp) = hi_filler;
+               *(--dp) = lo_filler;
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+            }
+            *(--dp) = hi_filler;
+            *(--dp) = lo_filler;
+            row_info->channels = 2;
+            row_info->pixel_depth = 32;
+            row_info->rowbytes = row_width * 4;
+         }
+         /* This changes the data from GG to XXGG */
+         else
+         {
+            png_bytep sp = row + (png_size_t)row_width * 2;
+            png_bytep dp = sp  + (png_size_t)row_width * 2;
+            for (i = 0; i < row_width; i++)
+            {
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = hi_filler;
+               *(--dp) = lo_filler;
+            }
+            row_info->channels = 2;
+            row_info->pixel_depth = 32;
+            row_info->rowbytes = row_width * 4;
+         }
+      }
+   } /* COLOR_TYPE == GRAY */
+   else if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+   {
+      if(row_info->bit_depth == 8)
+      {
+         /* This changes the data from RGB to RGBX */
+         if (flags & PNG_FLAG_FILLER_AFTER)
+         {
+            png_bytep sp = row + (png_size_t)row_width * 3;
+            png_bytep dp = sp  + (png_size_t)row_width;
+            for (i = 1; i < row_width; i++)
+            {
+               *(--dp) = lo_filler;
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+            }
+            *(--dp) = lo_filler;
+            row_info->channels = 4;
+            row_info->pixel_depth = 32;
+            row_info->rowbytes = row_width * 4;
+         }
+      /* This changes the data from RGB to XRGB */
+         else
+         {
+            png_bytep sp = row + (png_size_t)row_width * 3;
+            png_bytep dp = sp + (png_size_t)row_width;
+            for (i = 0; i < row_width; i++)
+            {
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = lo_filler;
+            }
+            row_info->channels = 4;
+            row_info->pixel_depth = 32;
+            row_info->rowbytes = row_width * 4;
+         }
+      }
+      else if(row_info->bit_depth == 16)
+      {
+         /* This changes the data from RRGGBB to RRGGBBXX */
+         if (flags & PNG_FLAG_FILLER_AFTER)
+         {
+            png_bytep sp = row + (png_size_t)row_width * 6;
+            png_bytep dp = sp  + (png_size_t)row_width * 2;
+            for (i = 1; i < row_width; i++)
+            {
+               *(--dp) = hi_filler;
+               *(--dp) = lo_filler;
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+            }
+            *(--dp) = hi_filler;
+            *(--dp) = lo_filler;
+            row_info->channels = 4;
+            row_info->pixel_depth = 64;
+            row_info->rowbytes = row_width * 8;
+         }
+         /* This changes the data from RRGGBB to XXRRGGBB */
+         else
+         {
+            png_bytep sp = row + (png_size_t)row_width * 6;
+            png_bytep dp = sp  + (png_size_t)row_width * 2;
+            for (i = 0; i < row_width; i++)
+            {
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = *(--sp);
+               *(--dp) = hi_filler;
+               *(--dp) = lo_filler;
+            }
+            row_info->channels = 4;
+            row_info->pixel_depth = 64;
+            row_info->rowbytes = row_width * 8;
+         }
+      }
+   } /* COLOR_TYPE == RGB */
+}
+#endif
+
+#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
+/* expand grayscale files to RGB, with or without alpha */
+void /* PRIVATE */
+png_do_gray_to_rgb(png_row_infop row_info, png_bytep row)
+{
+   png_uint_32 i;
+   png_uint_32 row_width = row_info->width;
+
+   png_debug(1, "in png_do_gray_to_rgb\n");
+   if (row_info->bit_depth >= 8 &&
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+       row != NULL && row_info != NULL &&
+#endif
+      !(row_info->color_type & PNG_COLOR_MASK_COLOR))
+   {
+      if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
+      {
+         if (row_info->bit_depth == 8)
+         {
+            png_bytep sp = row + (png_size_t)row_width - 1;
+            png_bytep dp = sp  + (png_size_t)row_width * 2;
+            for (i = 0; i < row_width; i++)
+            {
+               *(dp--) = *sp;
+               *(dp--) = *sp;
+               *(dp--) = *(sp--);
+            }
+         }
+         else
+         {
+            png_bytep sp = row + (png_size_t)row_width * 2 - 1;
+            png_bytep dp = sp  + (png_size_t)row_width * 4;
+            for (i = 0; i < row_width; i++)
+            {
+               *(dp--) = *sp;
+               *(dp--) = *(sp - 1);
+               *(dp--) = *sp;
+               *(dp--) = *(sp - 1);
+               *(dp--) = *(sp--);
+               *(dp--) = *(sp--);
+            }
+         }
+      }
+      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      {
+         if (row_info->bit_depth == 8)
+         {
+            png_bytep sp = row + (png_size_t)row_width * 2 - 1;
+            png_bytep dp = sp  + (png_size_t)row_width * 2;
+            for (i = 0; i < row_width; i++)
+            {
+               *(dp--) = *(sp--);
+               *(dp--) = *sp;
+               *(dp--) = *sp;
+               *(dp--) = *(sp--);
+            }
+         }
+         else
+         {
+            png_bytep sp = row + (png_size_t)row_width * 4 - 1;
+            png_bytep dp = sp  + (png_size_t)row_width * 4;
+            for (i = 0; i < row_width; i++)
+            {
+               *(dp--) = *(sp--);
+               *(dp--) = *(sp--);
+               *(dp--) = *sp;
+               *(dp--) = *(sp - 1);
+               *(dp--) = *sp;
+               *(dp--) = *(sp - 1);
+               *(dp--) = *(sp--);
+               *(dp--) = *(sp--);
+            }
+         }
+      }
+      row_info->channels += (png_byte)2;
+      row_info->color_type |= PNG_COLOR_MASK_COLOR;
+      row_info->pixel_depth = (png_byte)(row_info->channels *
+         row_info->bit_depth);
+      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,row_width);
+   }
+}
+#endif
+
+#if defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+/* reduce RGB files to grayscale, with or without alpha
+ * using the equation given in Poynton's ColorFAQ at
+ * <http://www.inforamp.net/~poynton/>
+ * Copyright (c) 1998-01-04 Charles Poynton poynton at inforamp.net
+ *
+ *     Y = 0.212671 * R + 0.715160 * G + 0.072169 * B
+ *
+ *  We approximate this with
+ *
+ *     Y = 0.21268 * R    + 0.7151 * G    + 0.07217 * B
+ *
+ *  which can be expressed with integers as
+ *
+ *     Y = (6969 * R + 23434 * G + 2365 * B)/32768
+ *
+ *  The calculation is to be done in a linear colorspace.
+ *
+ *  Other integer coefficents can be used via png_set_rgb_to_gray().
+ */
+int /* PRIVATE */
+png_do_rgb_to_gray(png_structp png_ptr, png_row_infop row_info, png_bytep row)
+
+{
+   png_uint_32 i;
+
+   png_uint_32 row_width = row_info->width;
+   int rgb_error = 0;
+
+   png_debug(1, "in png_do_rgb_to_gray\n");
+   if (
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+       row != NULL && row_info != NULL &&
+#endif
+      (row_info->color_type & PNG_COLOR_MASK_COLOR))
+   {
+      png_uint_32 rc = png_ptr->rgb_to_gray_red_coeff;
+      png_uint_32 gc = png_ptr->rgb_to_gray_green_coeff;
+      png_uint_32 bc = png_ptr->rgb_to_gray_blue_coeff;
+
+      if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+      {
+         if (row_info->bit_depth == 8)
+         {
+#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
+            if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL)
+            {
+               png_bytep sp = row;
+               png_bytep dp = row;
+
+               for (i = 0; i < row_width; i++)
+               {
+                  png_byte red   = png_ptr->gamma_to_1[*(sp++)];
+                  png_byte green = png_ptr->gamma_to_1[*(sp++)];
+                  png_byte blue  = png_ptr->gamma_to_1[*(sp++)];
+                  if(red != green || red != blue)
+                  {
+                     rgb_error |= 1;
+                     *(dp++) = png_ptr->gamma_from_1[
+                       (rc*red+gc*green+bc*blue)>>15];
+                  }
+                  else
+                     *(dp++) = *(sp-1);
+               }
+            }
+            else
+#endif
+            {
+               png_bytep sp = row;
+               png_bytep dp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  png_byte red   = *(sp++);
+                  png_byte green = *(sp++);
+                  png_byte blue  = *(sp++);
+                  if(red != green || red != blue)
+                  {
+                     rgb_error |= 1;
+                     *(dp++) = (png_byte)((rc*red+gc*green+bc*blue)>>15);
+                  }
+                  else
+                     *(dp++) = *(sp-1);
+               }
+            }
+         }
+
+         else /* RGB bit_depth == 16 */
+         {
+#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
+            if (png_ptr->gamma_16_to_1 != NULL &&
+                png_ptr->gamma_16_from_1 != NULL)
+            {
+               png_bytep sp = row;
+               png_bytep dp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  png_uint_16 red, green, blue, w;
+
+                  red   = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
+                  green = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
+                  blue  = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
+
+                  if(red == green && red == blue)
+                     w = red;
+                  else
+                  {
+                     png_uint_16 red_1   = png_ptr->gamma_16_to_1[(red&0xff) >>
+                                  png_ptr->gamma_shift][red>>8];
+                     png_uint_16 green_1 = png_ptr->gamma_16_to_1[(green&0xff) >>
+                                  png_ptr->gamma_shift][green>>8];
+                     png_uint_16 blue_1  = png_ptr->gamma_16_to_1[(blue&0xff) >>
+                                  png_ptr->gamma_shift][blue>>8];
+                     png_uint_16 gray16  = (png_uint_16)((rc*red_1 + gc*green_1
+                                  + bc*blue_1)>>15);
+                     w = png_ptr->gamma_16_from_1[(gray16&0xff) >>
+                         png_ptr->gamma_shift][gray16 >> 8];
+                     rgb_error |= 1;
+                  }
+
+                  *(dp++) = (png_byte)((w>>8) & 0xff);
+                  *(dp++) = (png_byte)(w & 0xff);
+               }
+            }
+            else
+#endif
+            {
+               png_bytep sp = row;
+               png_bytep dp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  png_uint_16 red, green, blue, gray16;
+
+                  red   = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
+                  green = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
+                  blue  = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
+
+                  if(red != green || red != blue)
+                     rgb_error |= 1;
+                  gray16  = (png_uint_16)((rc*red + gc*green + bc*blue)>>15);
+                  *(dp++) = (png_byte)((gray16>>8) & 0xff);
+                  *(dp++) = (png_byte)(gray16 & 0xff);
+               }
+            }
+         }
+      }
+      if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+      {
+         if (row_info->bit_depth == 8)
+         {
+#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
+            if (png_ptr->gamma_from_1 != NULL && png_ptr->gamma_to_1 != NULL)
+            {
+               png_bytep sp = row;
+               png_bytep dp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  png_byte red   = png_ptr->gamma_to_1[*(sp++)];
+                  png_byte green = png_ptr->gamma_to_1[*(sp++)];
+                  png_byte blue  = png_ptr->gamma_to_1[*(sp++)];
+                  if(red != green || red != blue)
+                     rgb_error |= 1;
+                  *(dp++) =  png_ptr->gamma_from_1
+                             [(rc*red + gc*green + bc*blue)>>15];
+                  *(dp++) = *(sp++);  /* alpha */
+               }
+            }
+            else
+#endif
+            {
+               png_bytep sp = row;
+               png_bytep dp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  png_byte red   = *(sp++);
+                  png_byte green = *(sp++);
+                  png_byte blue  = *(sp++);
+                  if(red != green || red != blue)
+                     rgb_error |= 1;
+                  *(dp++) =  (png_byte)((rc*red + gc*green + bc*blue)>>15);
+                  *(dp++) = *(sp++);  /* alpha */
+               }
+            }
+         }
+         else /* RGBA bit_depth == 16 */
+         {
+#if defined(PNG_READ_GAMMA_SUPPORTED) || defined(PNG_READ_BACKGROUND_SUPPORTED)
+            if (png_ptr->gamma_16_to_1 != NULL &&
+                png_ptr->gamma_16_from_1 != NULL)
+            {
+               png_bytep sp = row;
+               png_bytep dp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  png_uint_16 red, green, blue, w;
+
+                  red   = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
+                  green = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
+                  blue  = (png_uint_16)(((*(sp))<<8) | *(sp+1)); sp+=2;
+
+                  if(red == green && red == blue)
+                     w = red;
+                  else
+                  {
+                     png_uint_16 red_1   = png_ptr->gamma_16_to_1[(red&0xff) >>
+                                  png_ptr->gamma_shift][red>>8];
+                     png_uint_16 green_1 = png_ptr->gamma_16_to_1[(green&0xff) >>
+                                  png_ptr->gamma_shift][green>>8];
+                     png_uint_16 blue_1  = png_ptr->gamma_16_to_1[(blue&0xff) >>
+                                  png_ptr->gamma_shift][blue>>8];
+                     png_uint_16 gray16  = (png_uint_16)((rc * red_1
+                                  + gc * green_1 + bc * blue_1)>>15);
+                     w = png_ptr->gamma_16_from_1[(gray16&0xff) >>
+                         png_ptr->gamma_shift][gray16 >> 8];
+                     rgb_error |= 1;
+                  }
+
+                  *(dp++) = (png_byte)((w>>8) & 0xff);
+                  *(dp++) = (png_byte)(w & 0xff);
+                  *(dp++) = *(sp++);  /* alpha */
+                  *(dp++) = *(sp++);
+               }
+            }
+            else
+#endif
+            {
+               png_bytep sp = row;
+               png_bytep dp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  png_uint_16 red, green, blue, gray16;
+                  red   = (png_uint_16)((*(sp)<<8) | *(sp+1)); sp+=2;
+                  green = (png_uint_16)((*(sp)<<8) | *(sp+1)); sp+=2;
+                  blue  = (png_uint_16)((*(sp)<<8) | *(sp+1)); sp+=2;
+                  if(red != green || red != blue)
+                     rgb_error |= 1;
+                  gray16  = (png_uint_16)((rc*red + gc*green + bc*blue)>>15);
+                  *(dp++) = (png_byte)((gray16>>8) & 0xff);
+                  *(dp++) = (png_byte)(gray16 & 0xff);
+                  *(dp++) = *(sp++);  /* alpha */
+                  *(dp++) = *(sp++);
+               }
+            }
+         }
+      }
+   row_info->channels -= (png_byte)2;
+      row_info->color_type &= ~PNG_COLOR_MASK_COLOR;
+      row_info->pixel_depth = (png_byte)(row_info->channels *
+         row_info->bit_depth);
+      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,row_width);
+   }
+   return rgb_error;
+}
+#endif
+
+/* Build a grayscale palette.  Palette is assumed to be 1 << bit_depth
+ * large of png_color.  This lets grayscale images be treated as
+ * paletted.  Most useful for gamma correction and simplification
+ * of code.
+ */
+void PNGAPI
+png_build_grayscale_palette(int bit_depth, png_colorp palette)
+{
+   int num_palette;
+   int color_inc;
+   int i;
+   int v;
+
+   png_debug(1, "in png_do_build_grayscale_palette\n");
+   if (palette == NULL)
+      return;
+
+   switch (bit_depth)
+   {
+      case 1:
+         num_palette = 2;
+         color_inc = 0xff;
+         break;
+      case 2:
+         num_palette = 4;
+         color_inc = 0x55;
+         break;
+      case 4:
+         num_palette = 16;
+         color_inc = 0x11;
+         break;
+      case 8:
+         num_palette = 256;
+         color_inc = 1;
+         break;
+      default:
+         num_palette = 0;
+         color_inc = 0;
+         break;
+   }
+
+   for (i = 0, v = 0; i < num_palette; i++, v += color_inc)
+   {
+      palette[i].red = (png_byte)v;
+      palette[i].green = (png_byte)v;
+      palette[i].blue = (png_byte)v;
+   }
+}
+
+/* This function is currently unused.  Do we really need it? */
+#if defined(PNG_READ_DITHER_SUPPORTED) && defined(PNG_CORRECT_PALETTE_SUPPORTED)
+void /* PRIVATE */
+png_correct_palette(png_structp png_ptr, png_colorp palette,
+   int num_palette)
+{
+   png_debug(1, "in png_correct_palette\n");
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) && \
+    defined(PNG_READ_GAMMA_SUPPORTED) && defined(PNG_FLOATING_POINT_SUPPORTED)
+   if (png_ptr->transformations & (PNG_GAMMA | PNG_BACKGROUND))
+   {
+      png_color back, back_1;
+
+      if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_FILE)
+      {
+         back.red = png_ptr->gamma_table[png_ptr->background.red];
+         back.green = png_ptr->gamma_table[png_ptr->background.green];
+         back.blue = png_ptr->gamma_table[png_ptr->background.blue];
+
+         back_1.red = png_ptr->gamma_to_1[png_ptr->background.red];
+         back_1.green = png_ptr->gamma_to_1[png_ptr->background.green];
+         back_1.blue = png_ptr->gamma_to_1[png_ptr->background.blue];
+      }
+      else
+      {
+         double g;
+
+         g = 1.0 / (png_ptr->background_gamma * png_ptr->screen_gamma);
+
+         if (png_ptr->background_gamma_type == PNG_BACKGROUND_GAMMA_SCREEN ||
+             fabs(g - 1.0) < PNG_GAMMA_THRESHOLD)
+         {
+            back.red = png_ptr->background.red;
+            back.green = png_ptr->background.green;
+            back.blue = png_ptr->background.blue;
+         }
+         else
+         {
+            back.red =
+               (png_byte)(pow((double)png_ptr->background.red/255, g) *
+                255.0 + 0.5);
+            back.green =
+               (png_byte)(pow((double)png_ptr->background.green/255, g) *
+                255.0 + 0.5);
+            back.blue =
+               (png_byte)(pow((double)png_ptr->background.blue/255, g) *
+                255.0 + 0.5);
+         }
+
+         g = 1.0 / png_ptr->background_gamma;
+
+         back_1.red =
+            (png_byte)(pow((double)png_ptr->background.red/255, g) *
+             255.0 + 0.5);
+         back_1.green =
+            (png_byte)(pow((double)png_ptr->background.green/255, g) *
+             255.0 + 0.5);
+         back_1.blue =
+            (png_byte)(pow((double)png_ptr->background.blue/255, g) *
+             255.0 + 0.5);
+      }
+
+      if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      {
+         png_uint_32 i;
+
+         for (i = 0; i < (png_uint_32)num_palette; i++)
+         {
+            if (i < png_ptr->num_trans && png_ptr->trans[i] == 0)
+            {
+               palette[i] = back;
+            }
+            else if (i < png_ptr->num_trans && png_ptr->trans[i] != 0xff)
+            {
+               png_byte v, w;
+
+               v = png_ptr->gamma_to_1[png_ptr->palette[i].red];
+               png_composite(w, v, png_ptr->trans[i], back_1.red);
+               palette[i].red = png_ptr->gamma_from_1[w];
+
+               v = png_ptr->gamma_to_1[png_ptr->palette[i].green];
+               png_composite(w, v, png_ptr->trans[i], back_1.green);
+               palette[i].green = png_ptr->gamma_from_1[w];
+
+               v = png_ptr->gamma_to_1[png_ptr->palette[i].blue];
+               png_composite(w, v, png_ptr->trans[i], back_1.blue);
+               palette[i].blue = png_ptr->gamma_from_1[w];
+            }
+            else
+            {
+               palette[i].red = png_ptr->gamma_table[palette[i].red];
+               palette[i].green = png_ptr->gamma_table[palette[i].green];
+               palette[i].blue = png_ptr->gamma_table[palette[i].blue];
+            }
+         }
+      }
+      else
+      {
+         int i;
+
+         for (i = 0; i < num_palette; i++)
+         {
+            if (palette[i].red == (png_byte)png_ptr->trans_values.gray)
+            {
+               palette[i] = back;
+            }
+            else
+            {
+               palette[i].red = png_ptr->gamma_table[palette[i].red];
+               palette[i].green = png_ptr->gamma_table[palette[i].green];
+               palette[i].blue = png_ptr->gamma_table[palette[i].blue];
+            }
+         }
+      }
+   }
+   else
+#endif
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+   if (png_ptr->transformations & PNG_GAMMA)
+   {
+      int i;
+
+      for (i = 0; i < num_palette; i++)
+      {
+         palette[i].red = png_ptr->gamma_table[palette[i].red];
+         palette[i].green = png_ptr->gamma_table[palette[i].green];
+         palette[i].blue = png_ptr->gamma_table[palette[i].blue];
+      }
+   }
+#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+   else
+#endif
+#endif
+#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+   if (png_ptr->transformations & PNG_BACKGROUND)
+   {
+      if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      {
+         png_color back;
+
+         back.red   = (png_byte)png_ptr->background.red;
+         back.green = (png_byte)png_ptr->background.green;
+         back.blue  = (png_byte)png_ptr->background.blue;
+
+         for (i = 0; i < (int)png_ptr->num_trans; i++)
+         {
+            if (png_ptr->trans[i] == 0)
+            {
+               palette[i].red = back.red;
+               palette[i].green = back.green;
+               palette[i].blue = back.blue;
+            }
+            else if (png_ptr->trans[i] != 0xff)
+            {
+               png_composite(palette[i].red, png_ptr->palette[i].red,
+                  png_ptr->trans[i], back.red);
+               png_composite(palette[i].green, png_ptr->palette[i].green,
+                  png_ptr->trans[i], back.green);
+               png_composite(palette[i].blue, png_ptr->palette[i].blue,
+                  png_ptr->trans[i], back.blue);
+            }
+         }
+      }
+      else /* assume grayscale palette (what else could it be?) */
+      {
+         int i;
+
+         for (i = 0; i < num_palette; i++)
+         {
+            if (i == (png_byte)png_ptr->trans_values.gray)
+            {
+               palette[i].red = (png_byte)png_ptr->background.red;
+               palette[i].green = (png_byte)png_ptr->background.green;
+               palette[i].blue = (png_byte)png_ptr->background.blue;
+            }
+         }
+      }
+   }
+#endif
+}
+#endif
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED)
+/* Replace any alpha or transparency with the supplied background color.
+ * "background" is already in the screen gamma, while "background_1" is
+ * at a gamma of 1.0.  Paletted files have already been taken care of.
+ */
+void /* PRIVATE */
+png_do_background(png_row_infop row_info, png_bytep row,
+   png_color_16p trans_values, png_color_16p background
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+   , png_color_16p background_1,
+   png_bytep gamma_table, png_bytep gamma_from_1, png_bytep gamma_to_1,
+   png_uint_16pp gamma_16, png_uint_16pp gamma_16_from_1,
+   png_uint_16pp gamma_16_to_1, int gamma_shift
+#endif
+   )
+{
+   png_bytep sp, dp;
+   png_uint_32 i;
+   png_uint_32 row_width=row_info->width;
+   int shift;
+
+   png_debug(1, "in png_do_background\n");
+   if (background != NULL &&
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+       row != NULL && row_info != NULL &&
+#endif
+      (!(row_info->color_type & PNG_COLOR_MASK_ALPHA) ||
+      (row_info->color_type != PNG_COLOR_TYPE_PALETTE && trans_values)))
+   {
+      switch (row_info->color_type)
+      {
+         case PNG_COLOR_TYPE_GRAY:
+         {
+            switch (row_info->bit_depth)
+            {
+               case 1:
+               {
+                  sp = row;
+                  shift = 7;
+                  for (i = 0; i < row_width; i++)
+                  {
+                     if ((png_uint_16)((*sp >> shift) & 0x01)
+                        == trans_values->gray)
+                     {
+                        *sp &= (png_byte)((0x7f7f >> (7 - shift)) & 0xff);
+                        *sp |= (png_byte)(background->gray << shift);
+                     }
+                     if (!shift)
+                     {
+                        shift = 7;
+                        sp++;
+                     }
+                     else
+                        shift--;
+                  }
+                  break;
+               }
+               case 2:
+               {
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+                  if (gamma_table != NULL)
+                  {
+                     sp = row;
+                     shift = 6;
+                     for (i = 0; i < row_width; i++)
+                     {
+                        if ((png_uint_16)((*sp >> shift) & 0x03)
+                            == trans_values->gray)
+                        {
+                           *sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
+                           *sp |= (png_byte)(background->gray << shift);
+                        }
+                        else
+                        {
+                           png_byte p = (png_byte)((*sp >> shift) & 0x03);
+                           png_byte g = (png_byte)((gamma_table [p | (p << 2) |
+                               (p << 4) | (p << 6)] >> 6) & 0x03);
+                           *sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
+                           *sp |= (png_byte)(g << shift);
+                        }
+                        if (!shift)
+                        {
+                           shift = 6;
+                           sp++;
+                        }
+                        else
+                           shift -= 2;
+                     }
+                  }
+                  else
+#endif
+                  {
+                     sp = row;
+                     shift = 6;
+                     for (i = 0; i < row_width; i++)
+                     {
+                        if ((png_uint_16)((*sp >> shift) & 0x03)
+                            == trans_values->gray)
+                        {
+                           *sp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
+                           *sp |= (png_byte)(background->gray << shift);
+                        }
+                        if (!shift)
+                        {
+                           shift = 6;
+                           sp++;
+                        }
+                        else
+                           shift -= 2;
+                     }
+                  }
+                  break;
+               }
+               case 4:
+               {
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+                  if (gamma_table != NULL)
+                  {
+                     sp = row;
+                     shift = 4;
+                     for (i = 0; i < row_width; i++)
+                     {
+                        if ((png_uint_16)((*sp >> shift) & 0x0f)
+                            == trans_values->gray)
+                        {
+                           *sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
+                           *sp |= (png_byte)(background->gray << shift);
+                        }
+                        else
+                        {
+                           png_byte p = (png_byte)((*sp >> shift) & 0x0f);
+                           png_byte g = (png_byte)((gamma_table[p |
+                             (p << 4)] >> 4) & 0x0f);
+                           *sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
+                           *sp |= (png_byte)(g << shift);
+                        }
+                        if (!shift)
+                        {
+                           shift = 4;
+                           sp++;
+                        }
+                        else
+                           shift -= 4;
+                     }
+                  }
+                  else
+#endif
+                  {
+                     sp = row;
+                     shift = 4;
+                     for (i = 0; i < row_width; i++)
+                     {
+                        if ((png_uint_16)((*sp >> shift) & 0x0f)
+                            == trans_values->gray)
+                        {
+                           *sp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
+                           *sp |= (png_byte)(background->gray << shift);
+                        }
+                        if (!shift)
+                        {
+                           shift = 4;
+                           sp++;
+                        }
+                        else
+                           shift -= 4;
+                     }
+                  }
+                  break;
+               }
+               case 8:
+               {
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+                  if (gamma_table != NULL)
+                  {
+                     sp = row;
+                     for (i = 0; i < row_width; i++, sp++)
+                     {
+                        if (*sp == trans_values->gray)
+                        {
+                           *sp = (png_byte)background->gray;
+                        }
+                        else
+                        {
+                           *sp = gamma_table[*sp];
+                        }
+                     }
+                  }
+                  else
+#endif
+                  {
+                     sp = row;
+                     for (i = 0; i < row_width; i++, sp++)
+                     {
+                        if (*sp == trans_values->gray)
+                        {
+                           *sp = (png_byte)background->gray;
+                        }
+                     }
+                  }
+                  break;
+               }
+               case 16:
+               {
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+                  if (gamma_16 != NULL)
+                  {
+                     sp = row;
+                     for (i = 0; i < row_width; i++, sp += 2)
+                     {
+                        png_uint_16 v;
+
+                        v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+                        if (v == trans_values->gray)
+                        {
+                           /* background is already in screen gamma */
+                           *sp = (png_byte)((background->gray >> 8) & 0xff);
+                           *(sp + 1) = (png_byte)(background->gray & 0xff);
+                        }
+                        else
+                        {
+                           v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
+                           *sp = (png_byte)((v >> 8) & 0xff);
+                           *(sp + 1) = (png_byte)(v & 0xff);
+                        }
+                     }
+                  }
+                  else
+#endif
+                  {
+                     sp = row;
+                     for (i = 0; i < row_width; i++, sp += 2)
+                     {
+                        png_uint_16 v;
+
+                        v = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+                        if (v == trans_values->gray)
+                        {
+                           *sp = (png_byte)((background->gray >> 8) & 0xff);
+                           *(sp + 1) = (png_byte)(background->gray & 0xff);
+                        }
+                     }
+                  }
+                  break;
+               }
+            }
+            break;
+         }
+         case PNG_COLOR_TYPE_RGB:
+         {
+            if (row_info->bit_depth == 8)
+            {
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+               if (gamma_table != NULL)
+               {
+                  sp = row;
+                  for (i = 0; i < row_width; i++, sp += 3)
+                  {
+                     if (*sp == trans_values->red &&
+                        *(sp + 1) == trans_values->green &&
+                        *(sp + 2) == trans_values->blue)
+                     {
+                        *sp = (png_byte)background->red;
+                        *(sp + 1) = (png_byte)background->green;
+                        *(sp + 2) = (png_byte)background->blue;
+                     }
+                     else
+                     {
+                        *sp = gamma_table[*sp];
+                        *(sp + 1) = gamma_table[*(sp + 1)];
+                        *(sp + 2) = gamma_table[*(sp + 2)];
+                     }
+                  }
+               }
+               else
+#endif
+               {
+                  sp = row;
+                  for (i = 0; i < row_width; i++, sp += 3)
+                  {
+                     if (*sp == trans_values->red &&
+                        *(sp + 1) == trans_values->green &&
+                        *(sp + 2) == trans_values->blue)
+                     {
+                        *sp = (png_byte)background->red;
+                        *(sp + 1) = (png_byte)background->green;
+                        *(sp + 2) = (png_byte)background->blue;
+                     }
+                  }
+               }
+            }
+            else /* if (row_info->bit_depth == 16) */
+            {
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+               if (gamma_16 != NULL)
+               {
+                  sp = row;
+                  for (i = 0; i < row_width; i++, sp += 6)
+                  {
+                     png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+                     png_uint_16 g = (png_uint_16)(((*(sp+2)) << 8) + *(sp+3));
+                     png_uint_16 b = (png_uint_16)(((*(sp+4)) << 8) + *(sp+5));
+                     if (r == trans_values->red && g == trans_values->green &&
+                        b == trans_values->blue)
+                     {
+                        /* background is already in screen gamma */
+                        *sp = (png_byte)((background->red >> 8) & 0xff);
+                        *(sp + 1) = (png_byte)(background->red & 0xff);
+                        *(sp + 2) = (png_byte)((background->green >> 8) & 0xff);
+                        *(sp + 3) = (png_byte)(background->green & 0xff);
+                        *(sp + 4) = (png_byte)((background->blue >> 8) & 0xff);
+                        *(sp + 5) = (png_byte)(background->blue & 0xff);
+                     }
+                     else
+                     {
+                        png_uint_16 v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
+                        *sp = (png_byte)((v >> 8) & 0xff);
+                        *(sp + 1) = (png_byte)(v & 0xff);
+                        v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
+                        *(sp + 2) = (png_byte)((v >> 8) & 0xff);
+                        *(sp + 3) = (png_byte)(v & 0xff);
+                        v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
+                        *(sp + 4) = (png_byte)((v >> 8) & 0xff);
+                        *(sp + 5) = (png_byte)(v & 0xff);
+                     }
+                  }
+               }
+               else
+#endif
+               {
+                  sp = row;
+                  for (i = 0; i < row_width; i++, sp += 6)
+                  {
+                     png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp+1));
+                     png_uint_16 g = (png_uint_16)(((*(sp+2)) << 8) + *(sp+3));
+                     png_uint_16 b = (png_uint_16)(((*(sp+4)) << 8) + *(sp+5));
+
+                     if (r == trans_values->red && g == trans_values->green &&
+                        b == trans_values->blue)
+                     {
+                        *sp = (png_byte)((background->red >> 8) & 0xff);
+                        *(sp + 1) = (png_byte)(background->red & 0xff);
+                        *(sp + 2) = (png_byte)((background->green >> 8) & 0xff);
+                        *(sp + 3) = (png_byte)(background->green & 0xff);
+                        *(sp + 4) = (png_byte)((background->blue >> 8) & 0xff);
+                        *(sp + 5) = (png_byte)(background->blue & 0xff);
+                     }
+                  }
+               }
+            }
+            break;
+         }
+         case PNG_COLOR_TYPE_GRAY_ALPHA:
+         {
+            if (row_info->bit_depth == 8)
+            {
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+               if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
+                   gamma_table != NULL)
+               {
+                  sp = row;
+                  dp = row;
+                  for (i = 0; i < row_width; i++, sp += 2, dp++)
+                  {
+                     png_uint_16 a = *(sp + 1);
+
+                     if (a == 0xff)
+                     {
+                        *dp = gamma_table[*sp];
+                     }
+                     else if (a == 0)
+                     {
+                        /* background is already in screen gamma */
+                        *dp = (png_byte)background->gray;
+                     }
+                     else
+                     {
+                        png_byte v, w;
+
+                        v = gamma_to_1[*sp];
+                        png_composite(w, v, a, background_1->gray);
+                        *dp = gamma_from_1[w];
+                     }
+                  }
+               }
+               else
+#endif
+               {
+                  sp = row;
+                  dp = row;
+                  for (i = 0; i < row_width; i++, sp += 2, dp++)
+                  {
+                     png_byte a = *(sp + 1);
+
+                     if (a == 0xff)
+                     {
+                        *dp = *sp;
+                     }
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+                     else if (a == 0)
+                     {
+                        *dp = (png_byte)background->gray;
+                     }
+                     else
+                     {
+                        png_composite(*dp, *sp, a, background_1->gray);
+                     }
+#else
+                     *dp = (png_byte)background->gray;
+#endif
+                  }
+               }
+            }
+            else /* if (png_ptr->bit_depth == 16) */
+            {
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+               if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
+                   gamma_16_to_1 != NULL)
+               {
+                  sp = row;
+                  dp = row;
+                  for (i = 0; i < row_width; i++, sp += 4, dp += 2)
+                  {
+                     png_uint_16 a = (png_uint_16)(((*(sp+2)) << 8) + *(sp+3));
+
+                     if (a == (png_uint_16)0xffff)
+                     {
+                        png_uint_16 v;
+
+                        v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
+                        *dp = (png_byte)((v >> 8) & 0xff);
+                        *(dp + 1) = (png_byte)(v & 0xff);
+                     }
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+                     else if (a == 0)
+#else
+                     else
+#endif
+                     {
+                        /* background is already in screen gamma */
+                        *dp = (png_byte)((background->gray >> 8) & 0xff);
+                        *(dp + 1) = (png_byte)(background->gray & 0xff);
+                     }
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+                     else
+                     {
+                        png_uint_16 g, v, w;
+
+                        g = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
+                        png_composite_16(v, g, a, background_1->gray);
+                        w = gamma_16_from_1[(v&0xff) >> gamma_shift][v >> 8];
+                        *dp = (png_byte)((w >> 8) & 0xff);
+                        *(dp + 1) = (png_byte)(w & 0xff);
+                     }
+#endif
+                  }
+               }
+               else
+#endif
+               {
+                  sp = row;
+                  dp = row;
+                  for (i = 0; i < row_width; i++, sp += 4, dp += 2)
+                  {
+                     png_uint_16 a = (png_uint_16)(((*(sp+2)) << 8) + *(sp+3));
+                     if (a == (png_uint_16)0xffff)
+                     {
+                        png_memcpy(dp, sp, 2);
+                     }
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+                     else if (a == 0)
+#else
+                     else
+#endif
+                     {
+                        *dp = (png_byte)((background->gray >> 8) & 0xff);
+                        *(dp + 1) = (png_byte)(background->gray & 0xff);
+                     }
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+                     else
+                     {
+                        png_uint_16 g, v;
+
+                        g = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+                        png_composite_16(v, g, a, background_1->gray);
+                        *dp = (png_byte)((v >> 8) & 0xff);
+                        *(dp + 1) = (png_byte)(v & 0xff);
+                     }
+#endif
+                  }
+               }
+            }
+            break;
+         }
+         case PNG_COLOR_TYPE_RGB_ALPHA:
+         {
+            if (row_info->bit_depth == 8)
+            {
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+               if (gamma_to_1 != NULL && gamma_from_1 != NULL &&
+                   gamma_table != NULL)
+               {
+                  sp = row;
+                  dp = row;
+                  for (i = 0; i < row_width; i++, sp += 4, dp += 3)
+                  {
+                     png_byte a = *(sp + 3);
+
+                     if (a == 0xff)
+                     {
+                        *dp = gamma_table[*sp];
+                        *(dp + 1) = gamma_table[*(sp + 1)];
+                        *(dp + 2) = gamma_table[*(sp + 2)];
+                     }
+                     else if (a == 0)
+                     {
+                        /* background is already in screen gamma */
+                        *dp = (png_byte)background->red;
+                        *(dp + 1) = (png_byte)background->green;
+                        *(dp + 2) = (png_byte)background->blue;
+                     }
+                     else
+                     {
+                        png_byte v, w;
+
+                        v = gamma_to_1[*sp];
+                        png_composite(w, v, a, background_1->red);
+                        *dp = gamma_from_1[w];
+                        v = gamma_to_1[*(sp + 1)];
+                        png_composite(w, v, a, background_1->green);
+                        *(dp + 1) = gamma_from_1[w];
+                        v = gamma_to_1[*(sp + 2)];
+                        png_composite(w, v, a, background_1->blue);
+                        *(dp + 2) = gamma_from_1[w];
+                     }
+                  }
+               }
+               else
+#endif
+               {
+                  sp = row;
+                  dp = row;
+                  for (i = 0; i < row_width; i++, sp += 4, dp += 3)
+                  {
+                     png_byte a = *(sp + 3);
+
+                     if (a == 0xff)
+                     {
+                        *dp = *sp;
+                        *(dp + 1) = *(sp + 1);
+                        *(dp + 2) = *(sp + 2);
+                     }
+                     else if (a == 0)
+                     {
+                        *dp = (png_byte)background->red;
+                        *(dp + 1) = (png_byte)background->green;
+                        *(dp + 2) = (png_byte)background->blue;
+                     }
+                     else
+                     {
+                        png_composite(*dp, *sp, a, background->red);
+                        png_composite(*(dp + 1), *(sp + 1), a,
+                           background->green);
+                        png_composite(*(dp + 2), *(sp + 2), a,
+                           background->blue);
+                     }
+                  }
+               }
+            }
+            else /* if (row_info->bit_depth == 16) */
+            {
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+               if (gamma_16 != NULL && gamma_16_from_1 != NULL &&
+                   gamma_16_to_1 != NULL)
+               {
+                  sp = row;
+                  dp = row;
+                  for (i = 0; i < row_width; i++, sp += 8, dp += 6)
+                  {
+                     png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
+                         << 8) + (png_uint_16)(*(sp + 7)));
+                     if (a == (png_uint_16)0xffff)
+                     {
+                        png_uint_16 v;
+
+                        v = gamma_16[*(sp + 1) >> gamma_shift][*sp];
+                        *dp = (png_byte)((v >> 8) & 0xff);
+                        *(dp + 1) = (png_byte)(v & 0xff);
+                        v = gamma_16[*(sp + 3) >> gamma_shift][*(sp + 2)];
+                        *(dp + 2) = (png_byte)((v >> 8) & 0xff);
+                        *(dp + 3) = (png_byte)(v & 0xff);
+                        v = gamma_16[*(sp + 5) >> gamma_shift][*(sp + 4)];
+                        *(dp + 4) = (png_byte)((v >> 8) & 0xff);
+                        *(dp + 5) = (png_byte)(v & 0xff);
+                     }
+                     else if (a == 0)
+                     {
+                        /* background is already in screen gamma */
+                        *dp = (png_byte)((background->red >> 8) & 0xff);
+                        *(dp + 1) = (png_byte)(background->red & 0xff);
+                        *(dp + 2) = (png_byte)((background->green >> 8) & 0xff);
+                        *(dp + 3) = (png_byte)(background->green & 0xff);
+                        *(dp + 4) = (png_byte)((background->blue >> 8) & 0xff);
+                        *(dp + 5) = (png_byte)(background->blue & 0xff);
+                     }
+                     else
+                     {
+                        png_uint_16 v, w, x;
+
+                        v = gamma_16_to_1[*(sp + 1) >> gamma_shift][*sp];
+                        png_composite_16(w, v, a, background_1->red);
+                        x = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8];
+                        *dp = (png_byte)((x >> 8) & 0xff);
+                        *(dp + 1) = (png_byte)(x & 0xff);
+                        v = gamma_16_to_1[*(sp + 3) >> gamma_shift][*(sp + 2)];
+                        png_composite_16(w, v, a, background_1->green);
+                        x = gamma_16_from_1[((w&0xff) >> gamma_shift)][w >> 8];
+                        *(dp + 2) = (png_byte)((x >> 8) & 0xff);
+                        *(dp + 3) = (png_byte)(x & 0xff);
+                        v = gamma_16_to_1[*(sp + 5) >> gamma_shift][*(sp + 4)];
+                        png_composite_16(w, v, a, background_1->blue);
+                        x = gamma_16_from_1[(w & 0xff) >> gamma_shift][w >> 8];
+                        *(dp + 4) = (png_byte)((x >> 8) & 0xff);
+                        *(dp + 5) = (png_byte)(x & 0xff);
+                     }
+                  }
+               }
+               else
+#endif
+               {
+                  sp = row;
+                  dp = row;
+                  for (i = 0; i < row_width; i++, sp += 8, dp += 6)
+                  {
+                     png_uint_16 a = (png_uint_16)(((png_uint_16)(*(sp + 6))
+                        << 8) + (png_uint_16)(*(sp + 7)));
+                     if (a == (png_uint_16)0xffff)
+                     {
+                        png_memcpy(dp, sp, 6);
+                     }
+                     else if (a == 0)
+                     {
+                        *dp = (png_byte)((background->red >> 8) & 0xff);
+                        *(dp + 1) = (png_byte)(background->red & 0xff);
+                        *(dp + 2) = (png_byte)((background->green >> 8) & 0xff);
+                        *(dp + 3) = (png_byte)(background->green & 0xff);
+                        *(dp + 4) = (png_byte)((background->blue >> 8) & 0xff);
+                        *(dp + 5) = (png_byte)(background->blue & 0xff);
+                     }
+                     else
+                     {
+                        png_uint_16 v;
+
+                        png_uint_16 r = (png_uint_16)(((*sp) << 8) + *(sp + 1));
+                        png_uint_16 g = (png_uint_16)(((*(sp + 2)) << 8)
+                            + *(sp + 3));
+                        png_uint_16 b = (png_uint_16)(((*(sp + 4)) << 8)
+                            + *(sp + 5));
+
+                        png_composite_16(v, r, a, background->red);
+                        *dp = (png_byte)((v >> 8) & 0xff);
+                        *(dp + 1) = (png_byte)(v & 0xff);
+                        png_composite_16(v, g, a, background->green);
+                        *(dp + 2) = (png_byte)((v >> 8) & 0xff);
+                        *(dp + 3) = (png_byte)(v & 0xff);
+                        png_composite_16(v, b, a, background->blue);
+                        *(dp + 4) = (png_byte)((v >> 8) & 0xff);
+                        *(dp + 5) = (png_byte)(v & 0xff);
+                     }
+                  }
+               }
+            }
+            break;
+         }
+      }
+
+      if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
+      {
+         row_info->color_type &= ~PNG_COLOR_MASK_ALPHA;
+         row_info->channels--;
+         row_info->pixel_depth = (png_byte)(row_info->channels *
+            row_info->bit_depth);
+         row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,row_width);
+      }
+   }
+}
+#endif
+
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+/* Gamma correct the image, avoiding the alpha channel.  Make sure
+ * you do this after you deal with the transparency issue on grayscale
+ * or RGB images. If your bit depth is 8, use gamma_table, if it
+ * is 16, use gamma_16_table and gamma_shift.  Build these with
+ * build_gamma_table().
+ */
+void /* PRIVATE */
+png_do_gamma(png_row_infop row_info, png_bytep row,
+   png_bytep gamma_table, png_uint_16pp gamma_16_table,
+   int gamma_shift)
+{
+   png_bytep sp;
+   png_uint_32 i;
+   png_uint_32 row_width=row_info->width;
+
+   png_debug(1, "in png_do_gamma\n");
+   if (
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+       row != NULL && row_info != NULL &&
+#endif
+       ((row_info->bit_depth <= 8 && gamma_table != NULL) ||
+        (row_info->bit_depth == 16 && gamma_16_table != NULL)))
+   {
+      switch (row_info->color_type)
+      {
+         case PNG_COLOR_TYPE_RGB:
+         {
+            if (row_info->bit_depth == 8)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  *sp = gamma_table[*sp];
+                  sp++;
+                  *sp = gamma_table[*sp];
+                  sp++;
+                  *sp = gamma_table[*sp];
+                  sp++;
+               }
+            }
+            else /* if (row_info->bit_depth == 16) */
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  png_uint_16 v;
+
+                  v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+                  *sp = (png_byte)((v >> 8) & 0xff);
+                  *(sp + 1) = (png_byte)(v & 0xff);
+                  sp += 2;
+                  v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+                  *sp = (png_byte)((v >> 8) & 0xff);
+                  *(sp + 1) = (png_byte)(v & 0xff);
+                  sp += 2;
+                  v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+                  *sp = (png_byte)((v >> 8) & 0xff);
+                  *(sp + 1) = (png_byte)(v & 0xff);
+                  sp += 2;
+               }
+            }
+            break;
+         }
+         case PNG_COLOR_TYPE_RGB_ALPHA:
+         {
+            if (row_info->bit_depth == 8)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  *sp = gamma_table[*sp];
+                  sp++;
+                  *sp = gamma_table[*sp];
+                  sp++;
+                  *sp = gamma_table[*sp];
+                  sp++;
+                  sp++;
+               }
+            }
+            else /* if (row_info->bit_depth == 16) */
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+                  *sp = (png_byte)((v >> 8) & 0xff);
+                  *(sp + 1) = (png_byte)(v & 0xff);
+                  sp += 2;
+                  v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+                  *sp = (png_byte)((v >> 8) & 0xff);
+                  *(sp + 1) = (png_byte)(v & 0xff);
+                  sp += 2;
+                  v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+                  *sp = (png_byte)((v >> 8) & 0xff);
+                  *(sp + 1) = (png_byte)(v & 0xff);
+                  sp += 4;
+               }
+            }
+            break;
+         }
+         case PNG_COLOR_TYPE_GRAY_ALPHA:
+         {
+            if (row_info->bit_depth == 8)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  *sp = gamma_table[*sp];
+                  sp += 2;
+               }
+            }
+            else /* if (row_info->bit_depth == 16) */
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+                  *sp = (png_byte)((v >> 8) & 0xff);
+                  *(sp + 1) = (png_byte)(v & 0xff);
+                  sp += 4;
+               }
+            }
+            break;
+         }
+         case PNG_COLOR_TYPE_GRAY:
+         {
+            if (row_info->bit_depth == 2)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i += 4)
+               {
+                  int a = *sp & 0xc0;
+                  int b = *sp & 0x30;
+                  int c = *sp & 0x0c;
+                  int d = *sp & 0x03;
+
+                  *sp = (png_byte)(
+                        ((((int)gamma_table[a|(a>>2)|(a>>4)|(a>>6)])   ) & 0xc0)|
+                        ((((int)gamma_table[(b<<2)|b|(b>>2)|(b>>4)])>>2) & 0x30)|
+                        ((((int)gamma_table[(c<<4)|(c<<2)|c|(c>>2)])>>4) & 0x0c)|
+                        ((((int)gamma_table[(d<<6)|(d<<4)|(d<<2)|d])>>6) ));
+                  sp++;
+               }
+            }
+            if (row_info->bit_depth == 4)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i += 2)
+               {
+                  int msb = *sp & 0xf0;
+                  int lsb = *sp & 0x0f;
+
+                  *sp = (png_byte)((((int)gamma_table[msb | (msb >> 4)]) & 0xf0)
+                          | (((int)gamma_table[(lsb << 4) | lsb]) >> 4));
+                  sp++;
+               }
+            }
+            else if (row_info->bit_depth == 8)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  *sp = gamma_table[*sp];
+                  sp++;
+               }
+            }
+            else if (row_info->bit_depth == 16)
+            {
+               sp = row;
+               for (i = 0; i < row_width; i++)
+               {
+                  png_uint_16 v = gamma_16_table[*(sp + 1) >> gamma_shift][*sp];
+                  *sp = (png_byte)((v >> 8) & 0xff);
+                  *(sp + 1) = (png_byte)(v & 0xff);
+                  sp += 2;
+               }
+            }
+            break;
+         }
+      }
+   }
+}
+#endif
+
+#if defined(PNG_READ_EXPAND_SUPPORTED)
+/* Expands a palette row to an RGB or RGBA row depending
+ * upon whether you supply trans and num_trans.
+ */
+void /* PRIVATE */
+png_do_expand_palette(png_row_infop row_info, png_bytep row,
+   png_colorp palette, png_bytep trans, int num_trans)
+{
+   int shift, value;
+   png_bytep sp, dp;
+   png_uint_32 i;
+   png_uint_32 row_width=row_info->width;
+
+   png_debug(1, "in png_do_expand_palette\n");
+   if (
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+       row != NULL && row_info != NULL &&
+#endif
+       row_info->color_type == PNG_COLOR_TYPE_PALETTE)
+   {
+      if (row_info->bit_depth < 8)
+      {
+         switch (row_info->bit_depth)
+         {
+            case 1:
+            {
+               sp = row + (png_size_t)((row_width - 1) >> 3);
+               dp = row + (png_size_t)row_width - 1;
+               shift = 7 - (int)((row_width + 7) & 0x07);
+               for (i = 0; i < row_width; i++)
+               {
+                  if ((*sp >> shift) & 0x01)
+                     *dp = 1;
+                  else
+                     *dp = 0;
+                  if (shift == 7)
+                  {
+                     shift = 0;
+                     sp--;
+                  }
+                  else
+                     shift++;
+
+                  dp--;
+               }
+               break;
+            }
+            case 2:
+            {
+               sp = row + (png_size_t)((row_width - 1) >> 2);
+               dp = row + (png_size_t)row_width - 1;
+               shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
+               for (i = 0; i < row_width; i++)
+               {
+                  value = (*sp >> shift) & 0x03;
+                  *dp = (png_byte)value;
+                  if (shift == 6)
+                  {
+                     shift = 0;
+                     sp--;
+                  }
+                  else
+                     shift += 2;
+
+                  dp--;
+               }
+               break;
+            }
+            case 4:
+            {
+               sp = row + (png_size_t)((row_width - 1) >> 1);
+               dp = row + (png_size_t)row_width - 1;
+               shift = (int)((row_width & 0x01) << 2);
+               for (i = 0; i < row_width; i++)
+               {
+                  value = (*sp >> shift) & 0x0f;
+                  *dp = (png_byte)value;
+                  if (shift == 4)
+                  {
+                     shift = 0;
+                     sp--;
+                  }
+                  else
+                     shift += 4;
+
+                  dp--;
+               }
+               break;
+            }
+         }
+         row_info->bit_depth = 8;
+         row_info->pixel_depth = 8;
+         row_info->rowbytes = row_width;
+      }
+      switch (row_info->bit_depth)
+      {
+         case 8:
+         {
+            if (trans != NULL)
+            {
+               sp = row + (png_size_t)row_width - 1;
+               dp = row + (png_size_t)(row_width << 2) - 1;
+
+               for (i = 0; i < row_width; i++)
+               {
+                  if ((int)(*sp) >= num_trans)
+                     *dp-- = 0xff;
+                  else
+                     *dp-- = trans[*sp];
+                  *dp-- = palette[*sp].blue;
+                  *dp-- = palette[*sp].green;
+                  *dp-- = palette[*sp].red;
+                  sp--;
+               }
+               row_info->bit_depth = 8;
+               row_info->pixel_depth = 32;
+               row_info->rowbytes = row_width * 4;
+               row_info->color_type = 6;
+               row_info->channels = 4;
+            }
+            else
+            {
+               sp = row + (png_size_t)row_width - 1;
+               dp = row + (png_size_t)(row_width * 3) - 1;
+
+               for (i = 0; i < row_width; i++)
+               {
+                  *dp-- = palette[*sp].blue;
+                  *dp-- = palette[*sp].green;
+                  *dp-- = palette[*sp].red;
+                  sp--;
+               }
+               row_info->bit_depth = 8;
+               row_info->pixel_depth = 24;
+               row_info->rowbytes = row_width * 3;
+               row_info->color_type = 2;
+               row_info->channels = 3;
+            }
+            break;
+         }
+      }
+   }
+}
+
+/* If the bit depth < 8, it is expanded to 8.  Also, if the already
+ * expanded transparency value is supplied, an alpha channel is built.
+ */
+void /* PRIVATE */
+png_do_expand(png_row_infop row_info, png_bytep row,
+   png_color_16p trans_value)
+{
+   int shift, value;
+   png_bytep sp, dp;
+   png_uint_32 i;
+   png_uint_32 row_width=row_info->width;
+
+   png_debug(1, "in png_do_expand\n");
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+   if (row != NULL && row_info != NULL)
+#endif
+   {
+      if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
+      {
+         png_uint_16 gray = (png_uint_16)(trans_value ? trans_value->gray : 0);
+
+         if (row_info->bit_depth < 8)
+         {
+            switch (row_info->bit_depth)
+            {
+               case 1:
+               {
+                  gray = (png_uint_16)((gray&0x01)*0xff);
+                  sp = row + (png_size_t)((row_width - 1) >> 3);
+                  dp = row + (png_size_t)row_width - 1;
+                  shift = 7 - (int)((row_width + 7) & 0x07);
+                  for (i = 0; i < row_width; i++)
+                  {
+                     if ((*sp >> shift) & 0x01)
+                        *dp = 0xff;
+                     else
+                        *dp = 0;
+                     if (shift == 7)
+                     {
+                        shift = 0;
+                        sp--;
+                     }
+                     else
+                        shift++;
+
+                     dp--;
+                  }
+                  break;
+               }
+               case 2:
+               {
+                  gray = (png_uint_16)((gray&0x03)*0x55);
+                  sp = row + (png_size_t)((row_width - 1) >> 2);
+                  dp = row + (png_size_t)row_width - 1;
+                  shift = (int)((3 - ((row_width + 3) & 0x03)) << 1);
+                  for (i = 0; i < row_width; i++)
+                  {
+                     value = (*sp >> shift) & 0x03;
+                     *dp = (png_byte)(value | (value << 2) | (value << 4) |
+                        (value << 6));
+                     if (shift == 6)
+                     {
+                        shift = 0;
+                        sp--;
+                     }
+                     else
+                        shift += 2;
+
+                     dp--;
+                  }
+                  break;
+               }
+               case 4:
+               {
+                  gray = (png_uint_16)((gray&0x0f)*0x11);
+                  sp = row + (png_size_t)((row_width - 1) >> 1);
+                  dp = row + (png_size_t)row_width - 1;
+                  shift = (int)((1 - ((row_width + 1) & 0x01)) << 2);
+                  for (i = 0; i < row_width; i++)
+                  {
+                     value = (*sp >> shift) & 0x0f;
+                     *dp = (png_byte)(value | (value << 4));
+                     if (shift == 4)
+                     {
+                        shift = 0;
+                        sp--;
+                     }
+                     else
+                        shift = 4;
+
+                     dp--;
+                  }
+                  break;
+               }
+            }
+            row_info->bit_depth = 8;
+            row_info->pixel_depth = 8;
+            row_info->rowbytes = row_width;
+         }
+
+         if (trans_value != NULL)
+         {
+            if (row_info->bit_depth == 8)
+            {
+               gray = gray & 0xff;
+               sp = row + (png_size_t)row_width - 1;
+               dp = row + (png_size_t)(row_width << 1) - 1;
+               for (i = 0; i < row_width; i++)
+               {
+                  if (*sp == gray)
+                     *dp-- = 0;
+                  else
+                     *dp-- = 0xff;
+                  *dp-- = *sp--;
+               }
+            }
+            else if (row_info->bit_depth == 16)
+            {
+               png_byte gray_high = (gray >> 8) & 0xff;
+               png_byte gray_low = gray & 0xff;
+               sp = row + row_info->rowbytes - 1;
+               dp = row + (row_info->rowbytes << 1) - 1;
+               for (i = 0; i < row_width; i++)
+               {
+                  if (*(sp-1) == gray_high && *(sp) == gray_low) 
+                  {
+                     *dp-- = 0;
+                     *dp-- = 0;
+                  }
+                  else
+                  {
+                     *dp-- = 0xff;
+                     *dp-- = 0xff;
+                  }
+                  *dp-- = *sp--;
+                  *dp-- = *sp--;
+               }
+            }
+            row_info->color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
+            row_info->channels = 2;
+            row_info->pixel_depth = (png_byte)(row_info->bit_depth << 1);
+            row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
+               row_width);
+         }
+      }
+      else if (row_info->color_type == PNG_COLOR_TYPE_RGB && trans_value)
+      {
+         if (row_info->bit_depth == 8)
+         {
+            png_byte red = trans_value->red & 0xff;
+            png_byte green = trans_value->green & 0xff;
+            png_byte blue = trans_value->blue & 0xff;
+            sp = row + (png_size_t)row_info->rowbytes - 1;
+            dp = row + (png_size_t)(row_width << 2) - 1;
+            for (i = 0; i < row_width; i++)
+            {
+               if (*(sp - 2) == red && *(sp - 1) == green && *(sp) == blue)
+                  *dp-- = 0;
+               else
+                  *dp-- = 0xff;
+               *dp-- = *sp--;
+               *dp-- = *sp--;
+               *dp-- = *sp--;
+            }
+         }
+         else if (row_info->bit_depth == 16)
+         {
+            png_byte red_high = (trans_value->red > 8) & 0xff;
+            png_byte green_high = (trans_value->green > 8) & 0xff;
+            png_byte blue_high = (trans_value->blue > 8) & 0xff;
+            png_byte red_low = trans_value->red & 0xff;
+            png_byte green_low = trans_value->green & 0xff;
+            png_byte blue_low = trans_value->blue & 0xff;
+            sp = row + row_info->rowbytes - 1;
+            dp = row + (png_size_t)(row_width << 3) - 1;
+            for (i = 0; i < row_width; i++)
+            {
+               if (*(sp - 5) == red_high &&
+                  *(sp - 4) == red_low &&
+                  *(sp - 3) == green_high &&
+                  *(sp - 2) == green_low &&
+                  *(sp - 1) == blue_high &&
+                  *(sp    ) == blue_low)
+               {
+                  *dp-- = 0;
+                  *dp-- = 0;
+               }
+               else
+               {
+                  *dp-- = 0xff;
+                  *dp-- = 0xff;
+               }
+               *dp-- = *sp--;
+               *dp-- = *sp--;
+               *dp-- = *sp--;
+               *dp-- = *sp--;
+               *dp-- = *sp--;
+               *dp-- = *sp--;
+            }
+         }
+         row_info->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
+         row_info->channels = 4;
+         row_info->pixel_depth = (png_byte)(row_info->bit_depth << 2);
+         row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,row_width);
+      }
+   }
+}
+#endif
+
+#if defined(PNG_READ_DITHER_SUPPORTED)
+void /* PRIVATE */
+png_do_dither(png_row_infop row_info, png_bytep row,
+    png_bytep palette_lookup, png_bytep dither_lookup)
+{
+   png_bytep sp, dp;
+   png_uint_32 i;
+   png_uint_32 row_width=row_info->width;
+
+   png_debug(1, "in png_do_dither\n");
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+   if (row != NULL && row_info != NULL)
+#endif
+   {
+      if (row_info->color_type == PNG_COLOR_TYPE_RGB &&
+         palette_lookup && row_info->bit_depth == 8)
+      {
+         int r, g, b, p;
+         sp = row;
+         dp = row;
+         for (i = 0; i < row_width; i++)
+         {
+            r = *sp++;
+            g = *sp++;
+            b = *sp++;
+
+            /* this looks real messy, but the compiler will reduce
+               it down to a reasonable formula.  For example, with
+               5 bits per color, we get:
+               p = (((r >> 3) & 0x1f) << 10) |
+                  (((g >> 3) & 0x1f) << 5) |
+                  ((b >> 3) & 0x1f);
+               */
+            p = (((r >> (8 - PNG_DITHER_RED_BITS)) &
+               ((1 << PNG_DITHER_RED_BITS) - 1)) <<
+               (PNG_DITHER_GREEN_BITS + PNG_DITHER_BLUE_BITS)) |
+               (((g >> (8 - PNG_DITHER_GREEN_BITS)) &
+               ((1 << PNG_DITHER_GREEN_BITS) - 1)) <<
+               (PNG_DITHER_BLUE_BITS)) |
+               ((b >> (8 - PNG_DITHER_BLUE_BITS)) &
+               ((1 << PNG_DITHER_BLUE_BITS) - 1));
+
+            *dp++ = palette_lookup[p];
+         }
+         row_info->color_type = PNG_COLOR_TYPE_PALETTE;
+         row_info->channels = 1;
+         row_info->pixel_depth = row_info->bit_depth;
+         row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,row_width);
+      }
+      else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
+         palette_lookup != NULL && row_info->bit_depth == 8)
+      {
+         int r, g, b, p;
+         sp = row;
+         dp = row;
+         for (i = 0; i < row_width; i++)
+         {
+            r = *sp++;
+            g = *sp++;
+            b = *sp++;
+            sp++;
+
+            p = (((r >> (8 - PNG_DITHER_RED_BITS)) &
+               ((1 << PNG_DITHER_RED_BITS) - 1)) <<
+               (PNG_DITHER_GREEN_BITS + PNG_DITHER_BLUE_BITS)) |
+               (((g >> (8 - PNG_DITHER_GREEN_BITS)) &
+               ((1 << PNG_DITHER_GREEN_BITS) - 1)) <<
+               (PNG_DITHER_BLUE_BITS)) |
+               ((b >> (8 - PNG_DITHER_BLUE_BITS)) &
+               ((1 << PNG_DITHER_BLUE_BITS) - 1));
+
+            *dp++ = palette_lookup[p];
+         }
+         row_info->color_type = PNG_COLOR_TYPE_PALETTE;
+         row_info->channels = 1;
+         row_info->pixel_depth = row_info->bit_depth;
+         row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,row_width);
+      }
+      else if (row_info->color_type == PNG_COLOR_TYPE_PALETTE &&
+         dither_lookup && row_info->bit_depth == 8)
+      {
+         sp = row;
+         for (i = 0; i < row_width; i++, sp++)
+         {
+            *sp = dither_lookup[*sp];
+         }
+      }
+   }
+}
+#endif
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+#if defined(PNG_READ_GAMMA_SUPPORTED)
+static PNG_CONST int png_gamma_shift[] =
+   {0x10, 0x21, 0x42, 0x84, 0x110, 0x248, 0x550, 0xff0, 0x00};
+
+/* We build the 8- or 16-bit gamma tables here.  Note that for 16-bit
+ * tables, we don't make a full table if we are reducing to 8-bit in
+ * the future.  Note also how the gamma_16 tables are segmented so that
+ * we don't need to allocate > 64K chunks for a full 16-bit table.
+ */
+void /* PRIVATE */
+png_build_gamma_table(png_structp png_ptr)
+{
+  png_debug(1, "in png_build_gamma_table\n");
+
+  if (png_ptr->bit_depth <= 8)
+  {
+     int i;
+     double g;
+
+     if (png_ptr->screen_gamma > .000001)
+        g = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);
+     else
+        g = 1.0;
+
+     png_ptr->gamma_table = (png_bytep)png_malloc(png_ptr,
+        (png_uint_32)256);
+
+     for (i = 0; i < 256; i++)
+     {
+        png_ptr->gamma_table[i] = (png_byte)(pow((double)i / 255.0,
+           g) * 255.0 + .5);
+     }
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+   defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+     if (png_ptr->transformations & ((PNG_BACKGROUND) | PNG_RGB_TO_GRAY))
+     {
+
+        g = 1.0 / (png_ptr->gamma);
+
+        png_ptr->gamma_to_1 = (png_bytep)png_malloc(png_ptr,
+           (png_uint_32)256);
+
+        for (i = 0; i < 256; i++)
+        {
+           png_ptr->gamma_to_1[i] = (png_byte)(pow((double)i / 255.0,
+              g) * 255.0 + .5);
+        }
+
+
+        png_ptr->gamma_from_1 = (png_bytep)png_malloc(png_ptr,
+           (png_uint_32)256);
+
+        if(png_ptr->screen_gamma > 0.000001)
+           g = 1.0 / png_ptr->screen_gamma;
+        else
+           g = png_ptr->gamma;   /* probably doing rgb_to_gray */
+
+        for (i = 0; i < 256; i++)
+        {
+           png_ptr->gamma_from_1[i] = (png_byte)(pow((double)i / 255.0,
+              g) * 255.0 + .5);
+
+        }
+     }
+#endif /* PNG_READ_BACKGROUND_SUPPORTED || PNG_RGB_TO_GRAY_SUPPORTED */
+  }
+  else
+  {
+     double g;
+     int i, j, shift, num;
+     int sig_bit;
+     png_uint_32 ig;
+
+     if (png_ptr->color_type & PNG_COLOR_MASK_COLOR)
+     {
+        sig_bit = (int)png_ptr->sig_bit.red;
+        if ((int)png_ptr->sig_bit.green > sig_bit)
+           sig_bit = png_ptr->sig_bit.green;
+        if ((int)png_ptr->sig_bit.blue > sig_bit)
+           sig_bit = png_ptr->sig_bit.blue;
+     }
+     else
+     {
+        sig_bit = (int)png_ptr->sig_bit.gray;
+     }
+
+     if (sig_bit > 0)
+        shift = 16 - sig_bit;
+     else
+        shift = 0;
+
+     if (png_ptr->transformations & PNG_16_TO_8)
+     {
+        if (shift < (16 - PNG_MAX_GAMMA_8))
+           shift = (16 - PNG_MAX_GAMMA_8);
+     }
+
+     if (shift > 8)
+        shift = 8;
+     if (shift < 0)
+        shift = 0;
+
+     png_ptr->gamma_shift = (png_byte)shift;
+
+     num = (1 << (8 - shift));
+
+     if (png_ptr->screen_gamma > .000001)
+        g = 1.0 / (png_ptr->gamma * png_ptr->screen_gamma);
+     else
+        g = 1.0;
+
+     png_ptr->gamma_16_table = (png_uint_16pp)png_malloc(png_ptr,
+        (png_uint_32)(num * png_sizeof (png_uint_16p)));
+
+     if (png_ptr->transformations & (PNG_16_TO_8 | PNG_BACKGROUND))
+     {
+        double fin, fout;
+        png_uint_32 last, max;
+
+        for (i = 0; i < num; i++)
+        {
+           png_ptr->gamma_16_table[i] = (png_uint_16p)png_malloc(png_ptr,
+              (png_uint_32)(256 * png_sizeof (png_uint_16)));
+        }
+
+        g = 1.0 / g;
+        last = 0;
+        for (i = 0; i < 256; i++)
+        {
+           fout = ((double)i + 0.5) / 256.0;
+           fin = pow(fout, g);
+           max = (png_uint_32)(fin * (double)((png_uint_32)num << 8));
+           while (last <= max)
+           {
+              png_ptr->gamma_16_table[(int)(last & (0xff >> shift))]
+                 [(int)(last >> (8 - shift))] = (png_uint_16)(
+                 (png_uint_16)i | ((png_uint_16)i << 8));
+              last++;
+           }
+        }
+        while (last < ((png_uint_32)num << 8))
+        {
+           png_ptr->gamma_16_table[(int)(last & (0xff >> shift))]
+              [(int)(last >> (8 - shift))] = (png_uint_16)65535L;
+           last++;
+        }
+     }
+     else
+     {
+        for (i = 0; i < num; i++)
+        {
+           png_ptr->gamma_16_table[i] = (png_uint_16p)png_malloc(png_ptr,
+              (png_uint_32)(256 * png_sizeof (png_uint_16)));
+
+           ig = (((png_uint_32)i * (png_uint_32)png_gamma_shift[shift]) >> 4);
+           for (j = 0; j < 256; j++)
+           {
+              png_ptr->gamma_16_table[i][j] =
+                 (png_uint_16)(pow((double)(ig + ((png_uint_32)j << 8)) /
+                    65535.0, g) * 65535.0 + .5);
+           }
+        }
+     }
+
+#if defined(PNG_READ_BACKGROUND_SUPPORTED) || \
+   defined(PNG_READ_RGB_TO_GRAY_SUPPORTED)
+     if (png_ptr->transformations & (PNG_BACKGROUND | PNG_RGB_TO_GRAY))
+     {
+
+        g = 1.0 / (png_ptr->gamma);
+
+        png_ptr->gamma_16_to_1 = (png_uint_16pp)png_malloc(png_ptr,
+           (png_uint_32)(num * png_sizeof (png_uint_16p )));
+
+        for (i = 0; i < num; i++)
+        {
+           png_ptr->gamma_16_to_1[i] = (png_uint_16p)png_malloc(png_ptr,
+              (png_uint_32)(256 * png_sizeof (png_uint_16)));
+
+           ig = (((png_uint_32)i *
+              (png_uint_32)png_gamma_shift[shift]) >> 4);
+           for (j = 0; j < 256; j++)
+           {
+              png_ptr->gamma_16_to_1[i][j] =
+                 (png_uint_16)(pow((double)(ig + ((png_uint_32)j << 8)) /
+                    65535.0, g) * 65535.0 + .5);
+           }
+        }
+
+        if(png_ptr->screen_gamma > 0.000001)
+           g = 1.0 / png_ptr->screen_gamma;
+        else
+           g = png_ptr->gamma;   /* probably doing rgb_to_gray */
+
+        png_ptr->gamma_16_from_1 = (png_uint_16pp)png_malloc(png_ptr,
+           (png_uint_32)(num * png_sizeof (png_uint_16p)));
+
+        for (i = 0; i < num; i++)
+        {
+           png_ptr->gamma_16_from_1[i] = (png_uint_16p)png_malloc(png_ptr,
+              (png_uint_32)(256 * png_sizeof (png_uint_16)));
+
+           ig = (((png_uint_32)i *
+              (png_uint_32)png_gamma_shift[shift]) >> 4);
+           for (j = 0; j < 256; j++)
+           {
+              png_ptr->gamma_16_from_1[i][j] =
+                 (png_uint_16)(pow((double)(ig + ((png_uint_32)j << 8)) /
+                    65535.0, g) * 65535.0 + .5);
+           }
+        }
+     }
+#endif /* PNG_READ_BACKGROUND_SUPPORTED || PNG_RGB_TO_GRAY_SUPPORTED */
+  }
+}
+#endif
+/* To do: install integer version of png_build_gamma_table here */
+#endif
+
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
+/* undoes intrapixel differencing  */
+void /* PRIVATE */
+png_do_read_intrapixel(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_read_intrapixel\n");
+   if (
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+       row != NULL && row_info != NULL &&
+#endif
+       (row_info->color_type & PNG_COLOR_MASK_COLOR))
+   {
+      int bytes_per_pixel;
+      png_uint_32 row_width = row_info->width;
+      if (row_info->bit_depth == 8)
+      {
+         png_bytep rp;
+         png_uint_32 i;
+
+         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+            bytes_per_pixel = 3;
+         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+            bytes_per_pixel = 4;
+         else
+            return;
+
+         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
+         {
+            *(rp) = (png_byte)((256 + *rp + *(rp+1))&0xff);
+            *(rp+2) = (png_byte)((256 + *(rp+2) + *(rp+1))&0xff);
+         }
+      }
+      else if (row_info->bit_depth == 16)
+      {
+         png_bytep rp;
+         png_uint_32 i;
+
+         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+            bytes_per_pixel = 6;
+         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+            bytes_per_pixel = 8;
+         else
+            return;
+
+         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
+         {
+            png_uint_32 s0   = (*(rp  ) << 8) | *(rp+1);
+            png_uint_32 s1   = (*(rp+2) << 8) | *(rp+3);
+            png_uint_32 s2   = (*(rp+4) << 8) | *(rp+5);
+            png_uint_32 red  = (png_uint_32)((s0+s1+65536L) & 0xffffL);
+            png_uint_32 blue = (png_uint_32)((s2+s1+65536L) & 0xffffL);
+            *(rp  ) = (png_byte)((red >> 8) & 0xff);
+            *(rp+1) = (png_byte)(red & 0xff);
+            *(rp+4) = (png_byte)((blue >> 8) & 0xff);
+            *(rp+5) = (png_byte)(blue & 0xff);
+         }
+      }
+   }
+}
+#endif /* PNG_MNG_FEATURES_SUPPORTED */
+#endif /* PNG_READ_SUPPORTED */
diff --git a/distrib/libpng-1.2.19/pngrutil.c b/distrib/libpng-1.2.19/pngrutil.c
new file mode 100644
index 0000000..86e924c
--- /dev/null
+++ b/distrib/libpng-1.2.19/pngrutil.c
@@ -0,0 +1,4189 @@
+
+/* pngrutil.c - utilities to read a PNG file
+ *
+ * Last changed in libpng 1.2.19 August 18, 2007
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1998-2007 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This file contains routines that are only called from within
+ * libpng itself during the course of reading an image.
+ */
+
+#define PNG_INTERNAL
+#include "png.h"
+
+#if defined(PNG_READ_SUPPORTED)
+
+#if defined(_WIN32_WCE) && (_WIN32_WCE<0x500)
+#  define WIN32_WCE_OLD
+#endif
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+#  if defined(WIN32_WCE_OLD)
+/* strtod() function is not supported on WindowsCE */
+__inline double png_strtod(png_structp png_ptr, PNG_CONST char *nptr, char **endptr)
+{
+   double result = 0;
+   int len;
+   wchar_t *str, *end;
+
+   len = MultiByteToWideChar(CP_ACP, 0, nptr, -1, NULL, 0);
+   str = (wchar_t *)png_malloc(png_ptr, len * sizeof(wchar_t));
+   if ( NULL != str )
+   {
+      MultiByteToWideChar(CP_ACP, 0, nptr, -1, str, len);
+      result = wcstod(str, &end);
+      len = WideCharToMultiByte(CP_ACP, 0, end, -1, NULL, 0, NULL, NULL);
+      *endptr = (char *)nptr + (png_strlen(nptr) - len + 1);
+      png_free(png_ptr, str);
+   }
+   return result;
+}
+#  else
+#    define png_strtod(p,a,b) strtod(a,b)
+#  endif
+#endif
+
+png_uint_32 PNGAPI
+png_get_uint_31(png_structp png_ptr, png_bytep buf)
+{
+   png_uint_32 i = png_get_uint_32(buf);
+   if (i > PNG_UINT_31_MAX)
+     png_error(png_ptr, "PNG unsigned integer out of range.");
+   return (i);
+}
+#ifndef PNG_READ_BIG_ENDIAN_SUPPORTED
+/* Grab an unsigned 32-bit integer from a buffer in big-endian format. */
+png_uint_32 PNGAPI
+png_get_uint_32(png_bytep buf)
+{
+   png_uint_32 i = ((png_uint_32)(*buf) << 24) +
+      ((png_uint_32)(*(buf + 1)) << 16) +
+      ((png_uint_32)(*(buf + 2)) << 8) +
+      (png_uint_32)(*(buf + 3));
+
+   return (i);
+}
+
+/* Grab a signed 32-bit integer from a buffer in big-endian format.  The
+ * data is stored in the PNG file in two's complement format, and it is
+ * assumed that the machine format for signed integers is the same. */
+png_int_32 PNGAPI
+png_get_int_32(png_bytep buf)
+{
+   png_int_32 i = ((png_int_32)(*buf) << 24) +
+      ((png_int_32)(*(buf + 1)) << 16) +
+      ((png_int_32)(*(buf + 2)) << 8) +
+      (png_int_32)(*(buf + 3));
+
+   return (i);
+}
+
+/* Grab an unsigned 16-bit integer from a buffer in big-endian format. */
+png_uint_16 PNGAPI
+png_get_uint_16(png_bytep buf)
+{
+   png_uint_16 i = (png_uint_16)(((png_uint_16)(*buf) << 8) +
+      (png_uint_16)(*(buf + 1)));
+
+   return (i);
+}
+#endif /* PNG_READ_BIG_ENDIAN_SUPPORTED */
+
+/* Read data, and (optionally) run it through the CRC. */
+void /* PRIVATE */
+png_crc_read(png_structp png_ptr, png_bytep buf, png_size_t length)
+{
+   if(png_ptr == NULL) return;
+   png_read_data(png_ptr, buf, length);
+   png_calculate_crc(png_ptr, buf, length);
+}
+
+/* Optionally skip data and then check the CRC.  Depending on whether we
+   are reading a ancillary or critical chunk, and how the program has set
+   things up, we may calculate the CRC on the data and print a message.
+   Returns '1' if there was a CRC error, '0' otherwise. */
+int /* PRIVATE */
+png_crc_finish(png_structp png_ptr, png_uint_32 skip)
+{
+   png_size_t i;
+   png_size_t istop = png_ptr->zbuf_size;
+
+   for (i = (png_size_t)skip; i > istop; i -= istop)
+   {
+      png_crc_read(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
+   }
+   if (i)
+   {
+      png_crc_read(png_ptr, png_ptr->zbuf, i);
+   }
+
+   if (png_crc_error(png_ptr))
+   {
+      if (((png_ptr->chunk_name[0] & 0x20) &&                /* Ancillary */
+           !(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN)) ||
+          (!(png_ptr->chunk_name[0] & 0x20) &&             /* Critical  */
+          (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_USE)))
+      {
+         png_chunk_warning(png_ptr, "CRC error");
+      }
+      else
+      {
+         png_chunk_error(png_ptr, "CRC error");
+      }
+      return (1);
+   }
+
+   return (0);
+}
+
+/* Compare the CRC stored in the PNG file with that calculated by libpng from
+   the data it has read thus far. */
+int /* PRIVATE */
+png_crc_error(png_structp png_ptr)
+{
+   png_byte crc_bytes[4];
+   png_uint_32 crc;
+   int need_crc = 1;
+
+   if (png_ptr->chunk_name[0] & 0x20)                     /* ancillary */
+   {
+      if ((png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_MASK) ==
+          (PNG_FLAG_CRC_ANCILLARY_USE | PNG_FLAG_CRC_ANCILLARY_NOWARN))
+         need_crc = 0;
+   }
+   else                                                    /* critical */
+   {
+      if (png_ptr->flags & PNG_FLAG_CRC_CRITICAL_IGNORE)
+         need_crc = 0;
+   }
+
+   png_read_data(png_ptr, crc_bytes, 4);
+
+   if (need_crc)
+   {
+      crc = png_get_uint_32(crc_bytes);
+      return ((int)(crc != png_ptr->crc));
+   }
+   else
+      return (0);
+}
+
+#if defined(PNG_READ_zTXt_SUPPORTED) || defined(PNG_READ_iTXt_SUPPORTED) || \
+    defined(PNG_READ_iCCP_SUPPORTED)
+/*
+ * Decompress trailing data in a chunk.  The assumption is that chunkdata
+ * points at an allocated area holding the contents of a chunk with a
+ * trailing compressed part.  What we get back is an allocated area
+ * holding the original prefix part and an uncompressed version of the
+ * trailing part (the malloc area passed in is freed).
+ */
+png_charp /* PRIVATE */
+png_decompress_chunk(png_structp png_ptr, int comp_type,
+                              png_charp chunkdata, png_size_t chunklength,
+                              png_size_t prefix_size, png_size_t *newlength)
+{
+   static PNG_CONST char msg[] = "Error decoding compressed text";
+   png_charp text;
+   png_size_t text_size;
+
+   if (comp_type == PNG_COMPRESSION_TYPE_BASE)
+   {
+      int ret = Z_OK;
+      png_ptr->zstream.next_in = (png_bytep)(chunkdata + prefix_size);
+      png_ptr->zstream.avail_in = (uInt)(chunklength - prefix_size);
+      png_ptr->zstream.next_out = png_ptr->zbuf;
+      png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+
+      text_size = 0;
+      text = NULL;
+
+      while (png_ptr->zstream.avail_in)
+      {
+         ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
+         if (ret != Z_OK && ret != Z_STREAM_END)
+         {
+            if (png_ptr->zstream.msg != NULL)
+               png_warning(png_ptr, png_ptr->zstream.msg);
+            else
+               png_warning(png_ptr, msg);
+            inflateReset(&png_ptr->zstream);
+            png_ptr->zstream.avail_in = 0;
+
+            if (text ==  NULL)
+            {
+               text_size = prefix_size + png_sizeof(msg) + 1;
+               text = (png_charp)png_malloc_warn(png_ptr, text_size);
+               if (text ==  NULL)
+                 {
+                    png_free(png_ptr,chunkdata);
+                    png_error(png_ptr,"Not enough memory to decompress chunk");
+                 }
+               png_memcpy(text, chunkdata, prefix_size);
+            }
+
+            text[text_size - 1] = 0x00;
+
+            /* Copy what we can of the error message into the text chunk */
+            text_size = (png_size_t)(chunklength - (text - chunkdata) - 1);
+            text_size = png_sizeof(msg) > text_size ? text_size :
+               png_sizeof(msg);
+            png_memcpy(text + prefix_size, msg, text_size + 1);
+            break;
+         }
+         if (!png_ptr->zstream.avail_out || ret == Z_STREAM_END)
+         {
+            if (text == NULL)
+            {
+               text_size = prefix_size +
+                   png_ptr->zbuf_size - png_ptr->zstream.avail_out;
+               text = (png_charp)png_malloc_warn(png_ptr, text_size + 1);
+               if (text ==  NULL)
+                 {
+                    png_free(png_ptr,chunkdata);
+                    png_error(png_ptr,"Not enough memory to decompress chunk.");
+                 }
+               png_memcpy(text + prefix_size, png_ptr->zbuf,
+                    text_size - prefix_size);
+               png_memcpy(text, chunkdata, prefix_size);
+               *(text + text_size) = 0x00;
+            }
+            else
+            {
+               png_charp tmp;
+
+               tmp = text;
+               text = (png_charp)png_malloc_warn(png_ptr,
+                  (png_uint_32)(text_size +
+                  png_ptr->zbuf_size - png_ptr->zstream.avail_out + 1));
+               if (text == NULL)
+               {
+                  png_free(png_ptr, tmp);
+                  png_free(png_ptr, chunkdata);
+                  png_error(png_ptr,"Not enough memory to decompress chunk..");
+               }
+               png_memcpy(text, tmp, text_size);
+               png_free(png_ptr, tmp);
+               png_memcpy(text + text_size, png_ptr->zbuf,
+                  (png_ptr->zbuf_size - png_ptr->zstream.avail_out));
+               text_size += png_ptr->zbuf_size - png_ptr->zstream.avail_out;
+               *(text + text_size) = 0x00;
+            }
+            if (ret == Z_STREAM_END)
+               break;
+            else
+            {
+               png_ptr->zstream.next_out = png_ptr->zbuf;
+               png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+            }
+         }
+      }
+      if (ret != Z_STREAM_END)
+      {
+#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
+         char umsg[52];
+
+         if (ret == Z_BUF_ERROR)
+            png_snprintf(umsg, 52,
+                "Buffer error in compressed datastream in %s chunk",
+                png_ptr->chunk_name);
+         else if (ret == Z_DATA_ERROR)
+            png_snprintf(umsg, 52,
+                "Data error in compressed datastream in %s chunk",
+                png_ptr->chunk_name);
+         else
+            png_snprintf(umsg, 52,
+                "Incomplete compressed datastream in %s chunk",
+                png_ptr->chunk_name);
+         png_warning(png_ptr, umsg);
+#else
+         png_warning(png_ptr,
+            "Incomplete compressed datastream in chunk other than IDAT");
+#endif
+         text_size=prefix_size;
+         if (text ==  NULL)
+         {
+            text = (png_charp)png_malloc_warn(png_ptr, text_size+1);
+            if (text == NULL)
+              {
+                png_free(png_ptr, chunkdata);
+                png_error(png_ptr,"Not enough memory for text.");
+              }
+            png_memcpy(text, chunkdata, prefix_size);
+         }
+         *(text + text_size) = 0x00;
+      }
+
+      inflateReset(&png_ptr->zstream);
+      png_ptr->zstream.avail_in = 0;
+
+      png_free(png_ptr, chunkdata);
+      chunkdata = text;
+      *newlength=text_size;
+   }
+   else /* if (comp_type != PNG_COMPRESSION_TYPE_BASE) */
+   {
+#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
+      char umsg[50];
+
+      png_snprintf(umsg, 50,
+         "Unknown zTXt compression type %d", comp_type);
+      png_warning(png_ptr, umsg);
+#else
+      png_warning(png_ptr, "Unknown zTXt compression type");
+#endif
+
+      *(chunkdata + prefix_size) = 0x00;
+      *newlength=prefix_size;
+   }
+
+   return chunkdata;
+}
+#endif
+
+/* read and check the IDHR chunk */
+void /* PRIVATE */
+png_handle_IHDR(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+   png_byte buf[13];
+   png_uint_32 width, height;
+   int bit_depth, color_type, compression_type, filter_type;
+   int interlace_type;
+
+   png_debug(1, "in png_handle_IHDR\n");
+
+   if (png_ptr->mode & PNG_HAVE_IHDR)
+      png_error(png_ptr, "Out of place IHDR");
+
+   /* check the length */
+   if (length != 13)
+      png_error(png_ptr, "Invalid IHDR chunk");
+
+   png_ptr->mode |= PNG_HAVE_IHDR;
+
+   png_crc_read(png_ptr, buf, 13);
+   png_crc_finish(png_ptr, 0);
+
+   width = png_get_uint_31(png_ptr, buf);
+   height = png_get_uint_31(png_ptr, buf + 4);
+   bit_depth = buf[8];
+   color_type = buf[9];
+   compression_type = buf[10];
+   filter_type = buf[11];
+   interlace_type = buf[12];
+
+   /* set internal variables */
+   png_ptr->width = width;
+   png_ptr->height = height;
+   png_ptr->bit_depth = (png_byte)bit_depth;
+   png_ptr->interlaced = (png_byte)interlace_type;
+   png_ptr->color_type = (png_byte)color_type;
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
+   png_ptr->filter_type = (png_byte)filter_type;
+#endif
+   png_ptr->compression_type = (png_byte)compression_type;
+
+   /* find number of channels */
+   switch (png_ptr->color_type)
+   {
+      case PNG_COLOR_TYPE_GRAY:
+      case PNG_COLOR_TYPE_PALETTE:
+         png_ptr->channels = 1;
+         break;
+      case PNG_COLOR_TYPE_RGB:
+         png_ptr->channels = 3;
+         break;
+      case PNG_COLOR_TYPE_GRAY_ALPHA:
+         png_ptr->channels = 2;
+         break;
+      case PNG_COLOR_TYPE_RGB_ALPHA:
+         png_ptr->channels = 4;
+         break;
+   }
+
+   /* set up other useful info */
+   png_ptr->pixel_depth = (png_byte)(png_ptr->bit_depth *
+   png_ptr->channels);
+   png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth,png_ptr->width);
+   png_debug1(3,"bit_depth = %d\n", png_ptr->bit_depth);
+   png_debug1(3,"channels = %d\n", png_ptr->channels);
+   png_debug1(3,"rowbytes = %lu\n", png_ptr->rowbytes);
+   png_set_IHDR(png_ptr, info_ptr, width, height, bit_depth,
+      color_type, interlace_type, compression_type, filter_type);
+}
+
+/* read and check the palette */
+void /* PRIVATE */
+png_handle_PLTE(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+   png_color palette[PNG_MAX_PALETTE_LENGTH];
+   int num, i;
+#ifndef PNG_NO_POINTER_INDEXING
+   png_colorp pal_ptr;
+#endif
+
+   png_debug(1, "in png_handle_PLTE\n");
+
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Missing IHDR before PLTE");
+   else if (png_ptr->mode & PNG_HAVE_IDAT)
+   {
+      png_warning(png_ptr, "Invalid PLTE after IDAT");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+   else if (png_ptr->mode & PNG_HAVE_PLTE)
+      png_error(png_ptr, "Duplicate PLTE chunk");
+
+   png_ptr->mode |= PNG_HAVE_PLTE;
+
+   if (!(png_ptr->color_type&PNG_COLOR_MASK_COLOR))
+   {
+      png_warning(png_ptr,
+        "Ignoring PLTE chunk in grayscale PNG");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+#if !defined(PNG_READ_OPT_PLTE_SUPPORTED)
+   if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
+   {
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+#endif
+
+   if (length > 3*PNG_MAX_PALETTE_LENGTH || length % 3)
+   {
+      if (png_ptr->color_type != PNG_COLOR_TYPE_PALETTE)
+      {
+         png_warning(png_ptr, "Invalid palette chunk");
+         png_crc_finish(png_ptr, length);
+         return;
+      }
+      else
+      {
+         png_error(png_ptr, "Invalid palette chunk");
+      }
+   }
+
+   num = (int)length / 3;
+
+#ifndef PNG_NO_POINTER_INDEXING
+   for (i = 0, pal_ptr = palette; i < num; i++, pal_ptr++)
+   {
+      png_byte buf[3];
+
+      png_crc_read(png_ptr, buf, 3);
+      pal_ptr->red = buf[0];
+      pal_ptr->green = buf[1];
+      pal_ptr->blue = buf[2];
+   }
+#else
+   for (i = 0; i < num; i++)
+   {
+      png_byte buf[3];
+
+      png_crc_read(png_ptr, buf, 3);
+      /* don't depend upon png_color being any order */
+      palette[i].red = buf[0];
+      palette[i].green = buf[1];
+      palette[i].blue = buf[2];
+   }
+#endif
+
+   /* If we actually NEED the PLTE chunk (ie for a paletted image), we do
+      whatever the normal CRC configuration tells us.  However, if we
+      have an RGB image, the PLTE can be considered ancillary, so
+      we will act as though it is. */
+#if !defined(PNG_READ_OPT_PLTE_SUPPORTED)
+   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+#endif
+   {
+      png_crc_finish(png_ptr, 0);
+   }
+#if !defined(PNG_READ_OPT_PLTE_SUPPORTED)
+   else if (png_crc_error(png_ptr))  /* Only if we have a CRC error */
+   {
+      /* If we don't want to use the data from an ancillary chunk,
+         we have two options: an error abort, or a warning and we
+         ignore the data in this chunk (which should be OK, since
+         it's considered ancillary for a RGB or RGBA image). */
+      if (!(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_USE))
+      {
+         if (png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN)
+         {
+            png_chunk_error(png_ptr, "CRC error");
+         }
+         else
+         {
+            png_chunk_warning(png_ptr, "CRC error");
+            return;
+         }
+      }
+      /* Otherwise, we (optionally) emit a warning and use the chunk. */
+      else if (!(png_ptr->flags & PNG_FLAG_CRC_ANCILLARY_NOWARN))
+      {
+         png_chunk_warning(png_ptr, "CRC error");
+      }
+   }
+#endif
+
+   png_set_PLTE(png_ptr, info_ptr, palette, num);
+
+#if defined(PNG_READ_tRNS_SUPPORTED)
+   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+   {
+      if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS))
+      {
+         if (png_ptr->num_trans > (png_uint_16)num)
+         {
+            png_warning(png_ptr, "Truncating incorrect tRNS chunk length");
+            png_ptr->num_trans = (png_uint_16)num;
+         }
+         if (info_ptr->num_trans > (png_uint_16)num)
+         {
+            png_warning(png_ptr, "Truncating incorrect info tRNS chunk length");
+            info_ptr->num_trans = (png_uint_16)num;
+         }
+      }
+   }
+#endif
+
+}
+
+void /* PRIVATE */
+png_handle_IEND(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+   png_debug(1, "in png_handle_IEND\n");
+
+   if (!(png_ptr->mode & PNG_HAVE_IHDR) || !(png_ptr->mode & PNG_HAVE_IDAT))
+   {
+      png_error(png_ptr, "No image in file");
+   }
+
+   png_ptr->mode |= (PNG_AFTER_IDAT | PNG_HAVE_IEND);
+
+   if (length != 0)
+   {
+      png_warning(png_ptr, "Incorrect IEND chunk length");
+   }
+   png_crc_finish(png_ptr, length);
+
+   info_ptr =info_ptr; /* quiet compiler warnings about unused info_ptr */
+}
+
+#if defined(PNG_READ_gAMA_SUPPORTED)
+void /* PRIVATE */
+png_handle_gAMA(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+   png_fixed_point igamma;
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+   float file_gamma;
+#endif
+   png_byte buf[4];
+
+   png_debug(1, "in png_handle_gAMA\n");
+
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Missing IHDR before gAMA");
+   else if (png_ptr->mode & PNG_HAVE_IDAT)
+   {
+      png_warning(png_ptr, "Invalid gAMA after IDAT");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+   else if (png_ptr->mode & PNG_HAVE_PLTE)
+      /* Should be an error, but we can cope with it */
+      png_warning(png_ptr, "Out of place gAMA chunk");
+
+   if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_gAMA)
+#if defined(PNG_READ_sRGB_SUPPORTED)
+      && !(info_ptr->valid & PNG_INFO_sRGB)
+#endif
+      )
+   {
+      png_warning(png_ptr, "Duplicate gAMA chunk");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+   if (length != 4)
+   {
+      png_warning(png_ptr, "Incorrect gAMA chunk length");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+   png_crc_read(png_ptr, buf, 4);
+   if (png_crc_finish(png_ptr, 0))
+      return;
+
+   igamma = (png_fixed_point)png_get_uint_32(buf);
+   /* check for zero gamma */
+   if (igamma == 0)
+      {
+         png_warning(png_ptr,
+           "Ignoring gAMA chunk with gamma=0");
+         return;
+      }
+
+#if defined(PNG_READ_sRGB_SUPPORTED)
+   if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sRGB))
+      if (PNG_OUT_OF_RANGE(igamma, 45500L, 500))
+      {
+         png_warning(png_ptr,
+           "Ignoring incorrect gAMA value when sRGB is also present");
+#ifndef PNG_NO_CONSOLE_IO
+         fprintf(stderr, "gamma = (%d/100000)\n", (int)igamma);
+#endif
+         return;
+      }
+#endif /* PNG_READ_sRGB_SUPPORTED */
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+   file_gamma = (float)igamma / (float)100000.0;
+#  ifdef PNG_READ_GAMMA_SUPPORTED
+     png_ptr->gamma = file_gamma;
+#  endif
+     png_set_gAMA(png_ptr, info_ptr, file_gamma);
+#endif
+#ifdef PNG_FIXED_POINT_SUPPORTED
+   png_set_gAMA_fixed(png_ptr, info_ptr, igamma);
+#endif
+}
+#endif
+
+#if defined(PNG_READ_sBIT_SUPPORTED)
+void /* PRIVATE */
+png_handle_sBIT(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+   png_size_t truelen;
+   png_byte buf[4];
+
+   png_debug(1, "in png_handle_sBIT\n");
+
+   buf[0] = buf[1] = buf[2] = buf[3] = 0;
+
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Missing IHDR before sBIT");
+   else if (png_ptr->mode & PNG_HAVE_IDAT)
+   {
+      png_warning(png_ptr, "Invalid sBIT after IDAT");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+   else if (png_ptr->mode & PNG_HAVE_PLTE)
+   {
+      /* Should be an error, but we can cope with it */
+      png_warning(png_ptr, "Out of place sBIT chunk");
+   }
+   if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sBIT))
+   {
+      png_warning(png_ptr, "Duplicate sBIT chunk");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      truelen = 3;
+   else
+      truelen = (png_size_t)png_ptr->channels;
+
+   if (length != truelen || length > 4)
+   {
+      png_warning(png_ptr, "Incorrect sBIT chunk length");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+   png_crc_read(png_ptr, buf, truelen);
+   if (png_crc_finish(png_ptr, 0))
+      return;
+
+   if (png_ptr->color_type & PNG_COLOR_MASK_COLOR)
+   {
+      png_ptr->sig_bit.red = buf[0];
+      png_ptr->sig_bit.green = buf[1];
+      png_ptr->sig_bit.blue = buf[2];
+      png_ptr->sig_bit.alpha = buf[3];
+   }
+   else
+   {
+      png_ptr->sig_bit.gray = buf[0];
+      png_ptr->sig_bit.red = buf[0];
+      png_ptr->sig_bit.green = buf[0];
+      png_ptr->sig_bit.blue = buf[0];
+      png_ptr->sig_bit.alpha = buf[1];
+   }
+   png_set_sBIT(png_ptr, info_ptr, &(png_ptr->sig_bit));
+}
+#endif
+
+#if defined(PNG_READ_cHRM_SUPPORTED)
+void /* PRIVATE */
+png_handle_cHRM(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+   png_byte buf[4];
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+   float white_x, white_y, red_x, red_y, green_x, green_y, blue_x, blue_y;
+#endif
+   png_fixed_point int_x_white, int_y_white, int_x_red, int_y_red, int_x_green,
+      int_y_green, int_x_blue, int_y_blue;
+
+   png_uint_32 uint_x, uint_y;
+
+   png_debug(1, "in png_handle_cHRM\n");
+
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Missing IHDR before cHRM");
+   else if (png_ptr->mode & PNG_HAVE_IDAT)
+   {
+      png_warning(png_ptr, "Invalid cHRM after IDAT");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+   else if (png_ptr->mode & PNG_HAVE_PLTE)
+      /* Should be an error, but we can cope with it */
+      png_warning(png_ptr, "Missing PLTE before cHRM");
+
+   if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_cHRM)
+#if defined(PNG_READ_sRGB_SUPPORTED)
+      && !(info_ptr->valid & PNG_INFO_sRGB)
+#endif
+      )
+   {
+      png_warning(png_ptr, "Duplicate cHRM chunk");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+   if (length != 32)
+   {
+      png_warning(png_ptr, "Incorrect cHRM chunk length");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+   png_crc_read(png_ptr, buf, 4);
+   uint_x = png_get_uint_32(buf);
+
+   png_crc_read(png_ptr, buf, 4);
+   uint_y = png_get_uint_32(buf);
+
+   if (uint_x > 80000L || uint_y > 80000L ||
+      uint_x + uint_y > 100000L)
+   {
+      png_warning(png_ptr, "Invalid cHRM white point");
+      png_crc_finish(png_ptr, 24);
+      return;
+   }
+   int_x_white = (png_fixed_point)uint_x;
+   int_y_white = (png_fixed_point)uint_y;
+
+   png_crc_read(png_ptr, buf, 4);
+   uint_x = png_get_uint_32(buf);
+
+   png_crc_read(png_ptr, buf, 4);
+   uint_y = png_get_uint_32(buf);
+
+   if (uint_x + uint_y > 100000L)
+   {
+      png_warning(png_ptr, "Invalid cHRM red point");
+      png_crc_finish(png_ptr, 16);
+      return;
+   }
+   int_x_red = (png_fixed_point)uint_x;
+   int_y_red = (png_fixed_point)uint_y;
+
+   png_crc_read(png_ptr, buf, 4);
+   uint_x = png_get_uint_32(buf);
+
+   png_crc_read(png_ptr, buf, 4);
+   uint_y = png_get_uint_32(buf);
+
+   if (uint_x + uint_y > 100000L)
+   {
+      png_warning(png_ptr, "Invalid cHRM green point");
+      png_crc_finish(png_ptr, 8);
+      return;
+   }
+   int_x_green = (png_fixed_point)uint_x;
+   int_y_green = (png_fixed_point)uint_y;
+
+   png_crc_read(png_ptr, buf, 4);
+   uint_x = png_get_uint_32(buf);
+
+   png_crc_read(png_ptr, buf, 4);
+   uint_y = png_get_uint_32(buf);
+
+   if (uint_x + uint_y > 100000L)
+   {
+      png_warning(png_ptr, "Invalid cHRM blue point");
+      png_crc_finish(png_ptr, 0);
+      return;
+   }
+   int_x_blue = (png_fixed_point)uint_x;
+   int_y_blue = (png_fixed_point)uint_y;
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+   white_x = (float)int_x_white / (float)100000.0;
+   white_y = (float)int_y_white / (float)100000.0;
+   red_x   = (float)int_x_red   / (float)100000.0;
+   red_y   = (float)int_y_red   / (float)100000.0;
+   green_x = (float)int_x_green / (float)100000.0;
+   green_y = (float)int_y_green / (float)100000.0;
+   blue_x  = (float)int_x_blue  / (float)100000.0;
+   blue_y  = (float)int_y_blue  / (float)100000.0;
+#endif
+
+#if defined(PNG_READ_sRGB_SUPPORTED)
+   if ((info_ptr != NULL) && (info_ptr->valid & PNG_INFO_sRGB))
+      {
+      if (PNG_OUT_OF_RANGE(int_x_white, 31270,  1000) ||
+          PNG_OUT_OF_RANGE(int_y_white, 32900,  1000) ||
+          PNG_OUT_OF_RANGE(int_x_red,   64000L, 1000) ||
+          PNG_OUT_OF_RANGE(int_y_red,   33000,  1000) ||
+          PNG_OUT_OF_RANGE(int_x_green, 30000,  1000) ||
+          PNG_OUT_OF_RANGE(int_y_green, 60000L, 1000) ||
+          PNG_OUT_OF_RANGE(int_x_blue,  15000,  1000) ||
+          PNG_OUT_OF_RANGE(int_y_blue,   6000,  1000))
+         {
+            png_warning(png_ptr,
+              "Ignoring incorrect cHRM value when sRGB is also present");
+#ifndef PNG_NO_CONSOLE_IO
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+            fprintf(stderr,"wx=%f, wy=%f, rx=%f, ry=%f\n",
+               white_x, white_y, red_x, red_y);
+            fprintf(stderr,"gx=%f, gy=%f, bx=%f, by=%f\n",
+               green_x, green_y, blue_x, blue_y);
+#else
+            fprintf(stderr,"wx=%ld, wy=%ld, rx=%ld, ry=%ld\n",
+               int_x_white, int_y_white, int_x_red, int_y_red);
+            fprintf(stderr,"gx=%ld, gy=%ld, bx=%ld, by=%ld\n",
+               int_x_green, int_y_green, int_x_blue, int_y_blue);
+#endif
+#endif /* PNG_NO_CONSOLE_IO */
+         }
+         png_crc_finish(png_ptr, 0);
+         return;
+      }
+#endif /* PNG_READ_sRGB_SUPPORTED */
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+   png_set_cHRM(png_ptr, info_ptr,
+      white_x, white_y, red_x, red_y, green_x, green_y, blue_x, blue_y);
+#endif
+#ifdef PNG_FIXED_POINT_SUPPORTED
+   png_set_cHRM_fixed(png_ptr, info_ptr,
+      int_x_white, int_y_white, int_x_red, int_y_red, int_x_green,
+      int_y_green, int_x_blue, int_y_blue);
+#endif
+   if (png_crc_finish(png_ptr, 0))
+      return;
+}
+#endif
+
+#if defined(PNG_READ_sRGB_SUPPORTED)
+void /* PRIVATE */
+png_handle_sRGB(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+   int intent;
+   png_byte buf[1];
+
+   png_debug(1, "in png_handle_sRGB\n");
+
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Missing IHDR before sRGB");
+   else if (png_ptr->mode & PNG_HAVE_IDAT)
+   {
+      png_warning(png_ptr, "Invalid sRGB after IDAT");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+   else if (png_ptr->mode & PNG_HAVE_PLTE)
+      /* Should be an error, but we can cope with it */
+      png_warning(png_ptr, "Out of place sRGB chunk");
+
+   if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sRGB))
+   {
+      png_warning(png_ptr, "Duplicate sRGB chunk");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+   if (length != 1)
+   {
+      png_warning(png_ptr, "Incorrect sRGB chunk length");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+   png_crc_read(png_ptr, buf, 1);
+   if (png_crc_finish(png_ptr, 0))
+      return;
+
+   intent = buf[0];
+   /* check for bad intent */
+   if (intent >= PNG_sRGB_INTENT_LAST)
+   {
+      png_warning(png_ptr, "Unknown sRGB intent");
+      return;
+   }
+
+#if defined(PNG_READ_gAMA_SUPPORTED) && defined(PNG_READ_GAMMA_SUPPORTED)
+   if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_gAMA))
+   {
+   png_fixed_point igamma;
+#ifdef PNG_FIXED_POINT_SUPPORTED
+      igamma=info_ptr->int_gamma;
+#else
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+      igamma=(png_fixed_point)(info_ptr->gamma * 100000.);
+#  endif
+#endif
+      if (PNG_OUT_OF_RANGE(igamma, 45500L, 500))
+      {
+         png_warning(png_ptr,
+           "Ignoring incorrect gAMA value when sRGB is also present");
+#ifndef PNG_NO_CONSOLE_IO
+#  ifdef PNG_FIXED_POINT_SUPPORTED
+         fprintf(stderr,"incorrect gamma=(%d/100000)\n",(int)png_ptr->int_gamma);
+#  else
+#    ifdef PNG_FLOATING_POINT_SUPPORTED
+         fprintf(stderr,"incorrect gamma=%f\n",png_ptr->gamma);
+#    endif
+#  endif
+#endif
+      }
+   }
+#endif /* PNG_READ_gAMA_SUPPORTED */
+
+#ifdef PNG_READ_cHRM_SUPPORTED
+#ifdef PNG_FIXED_POINT_SUPPORTED
+   if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_cHRM))
+      if (PNG_OUT_OF_RANGE(info_ptr->int_x_white, 31270,  1000) ||
+          PNG_OUT_OF_RANGE(info_ptr->int_y_white, 32900,  1000) ||
+          PNG_OUT_OF_RANGE(info_ptr->int_x_red,   64000L, 1000) ||
+          PNG_OUT_OF_RANGE(info_ptr->int_y_red,   33000,  1000) ||
+          PNG_OUT_OF_RANGE(info_ptr->int_x_green, 30000,  1000) ||
+          PNG_OUT_OF_RANGE(info_ptr->int_y_green, 60000L, 1000) ||
+          PNG_OUT_OF_RANGE(info_ptr->int_x_blue,  15000,  1000) ||
+          PNG_OUT_OF_RANGE(info_ptr->int_y_blue,   6000,  1000))
+         {
+            png_warning(png_ptr,
+              "Ignoring incorrect cHRM value when sRGB is also present");
+         }
+#endif /* PNG_FIXED_POINT_SUPPORTED */
+#endif /* PNG_READ_cHRM_SUPPORTED */
+
+   png_set_sRGB_gAMA_and_cHRM(png_ptr, info_ptr, intent);
+}
+#endif /* PNG_READ_sRGB_SUPPORTED */
+
+#if defined(PNG_READ_iCCP_SUPPORTED)
+void /* PRIVATE */
+png_handle_iCCP(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+/* Note: this does not properly handle chunks that are > 64K under DOS */
+{
+   png_charp chunkdata;
+   png_byte compression_type;
+   png_bytep pC;
+   png_charp profile;
+   png_uint_32 skip = 0;
+   png_uint_32 profile_size, profile_length;
+   png_size_t slength, prefix_length, data_length;
+
+   png_debug(1, "in png_handle_iCCP\n");
+
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Missing IHDR before iCCP");
+   else if (png_ptr->mode & PNG_HAVE_IDAT)
+   {
+      png_warning(png_ptr, "Invalid iCCP after IDAT");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+   else if (png_ptr->mode & PNG_HAVE_PLTE)
+      /* Should be an error, but we can cope with it */
+      png_warning(png_ptr, "Out of place iCCP chunk");
+
+   if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_iCCP))
+   {
+      png_warning(png_ptr, "Duplicate iCCP chunk");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+#ifdef PNG_MAX_MALLOC_64K
+   if (length > (png_uint_32)65535L)
+   {
+      png_warning(png_ptr, "iCCP chunk too large to fit in memory");
+      skip = length - (png_uint_32)65535L;
+      length = (png_uint_32)65535L;
+   }
+#endif
+
+   chunkdata = (png_charp)png_malloc(png_ptr, length + 1);
+   slength = (png_size_t)length;
+   png_crc_read(png_ptr, (png_bytep)chunkdata, slength);
+
+   if (png_crc_finish(png_ptr, skip))
+   {
+      png_free(png_ptr, chunkdata);
+      return;
+   }
+
+   chunkdata[slength] = 0x00;
+
+   for (profile = chunkdata; *profile; profile++)
+      /* empty loop to find end of name */ ;
+
+   ++profile;
+
+   /* there should be at least one zero (the compression type byte)
+      following the separator, and we should be on it  */
+   if ( profile >= chunkdata + slength - 1)
+   {
+      png_free(png_ptr, chunkdata);
+      png_warning(png_ptr, "Malformed iCCP chunk");
+      return;
+   }
+
+   /* compression_type should always be zero */
+   compression_type = *profile++;
+   if (compression_type)
+   {
+      png_warning(png_ptr, "Ignoring nonzero compression type in iCCP chunk");
+      compression_type=0x00;  /* Reset it to zero (libpng-1.0.6 through 1.0.8
+                                 wrote nonzero) */
+   }
+
+   prefix_length = profile - chunkdata;
+   chunkdata = png_decompress_chunk(png_ptr, compression_type, chunkdata,
+                                    slength, prefix_length, &data_length);
+
+   profile_length = data_length - prefix_length;
+
+   if ( prefix_length > data_length || profile_length < 4)
+   {
+      png_free(png_ptr, chunkdata);
+      png_warning(png_ptr, "Profile size field missing from iCCP chunk");
+      return;
+   }
+
+   /* Check the profile_size recorded in the first 32 bits of the ICC profile */
+   pC = (png_bytep)(chunkdata+prefix_length);
+   profile_size = ((*(pC  ))<<24) |
+                  ((*(pC+1))<<16) |
+                  ((*(pC+2))<< 8) |
+                  ((*(pC+3))    );
+
+   if(profile_size < profile_length)
+      profile_length = profile_size;
+
+   if(profile_size > profile_length)
+   {
+      png_free(png_ptr, chunkdata);
+      png_warning(png_ptr, "Ignoring truncated iCCP profile.");
+      return;
+   }
+
+   png_set_iCCP(png_ptr, info_ptr, chunkdata, compression_type,
+                chunkdata + prefix_length, profile_length);
+   png_free(png_ptr, chunkdata);
+}
+#endif /* PNG_READ_iCCP_SUPPORTED */
+
+#if defined(PNG_READ_sPLT_SUPPORTED)
+void /* PRIVATE */
+png_handle_sPLT(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+/* Note: this does not properly handle chunks that are > 64K under DOS */
+{
+   png_bytep chunkdata;
+   png_bytep entry_start;
+   png_sPLT_t new_palette;
+#ifdef PNG_NO_POINTER_INDEXING
+   png_sPLT_entryp pp;
+#endif
+   int data_length, entry_size, i;
+   png_uint_32 skip = 0;
+   png_size_t slength;
+
+   png_debug(1, "in png_handle_sPLT\n");
+
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Missing IHDR before sPLT");
+   else if (png_ptr->mode & PNG_HAVE_IDAT)
+   {
+      png_warning(png_ptr, "Invalid sPLT after IDAT");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+#ifdef PNG_MAX_MALLOC_64K
+   if (length > (png_uint_32)65535L)
+   {
+      png_warning(png_ptr, "sPLT chunk too large to fit in memory");
+      skip = length - (png_uint_32)65535L;
+      length = (png_uint_32)65535L;
+   }
+#endif
+
+   chunkdata = (png_bytep)png_malloc(png_ptr, length + 1);
+   slength = (png_size_t)length;
+   png_crc_read(png_ptr, (png_bytep)chunkdata, slength);
+
+   if (png_crc_finish(png_ptr, skip))
+   {
+      png_free(png_ptr, chunkdata);
+      return;
+   }
+
+   chunkdata[slength] = 0x00;
+
+   for (entry_start = chunkdata; *entry_start; entry_start++)
+      /* empty loop to find end of name */ ;
+   ++entry_start;
+
+   /* a sample depth should follow the separator, and we should be on it  */
+   if (entry_start > chunkdata + slength - 2)
+   {
+      png_free(png_ptr, chunkdata);
+      png_warning(png_ptr, "malformed sPLT chunk");
+      return;
+   }
+
+   new_palette.depth = *entry_start++;
+   entry_size = (new_palette.depth == 8 ? 6 : 10);
+   data_length = (slength - (entry_start - chunkdata));
+
+   /* integrity-check the data length */
+   if (data_length % entry_size)
+   {
+      png_free(png_ptr, chunkdata);
+      png_warning(png_ptr, "sPLT chunk has bad length");
+      return;
+   }
+
+   new_palette.nentries = (png_int_32) ( data_length / entry_size);
+   if ((png_uint_32) new_palette.nentries > (png_uint_32) (PNG_SIZE_MAX /
+       png_sizeof(png_sPLT_entry)))
+   {
+       png_warning(png_ptr, "sPLT chunk too long");
+       return;
+   }
+   new_palette.entries = (png_sPLT_entryp)png_malloc_warn(
+       png_ptr, new_palette.nentries * png_sizeof(png_sPLT_entry));
+   if (new_palette.entries == NULL)
+   {
+       png_warning(png_ptr, "sPLT chunk requires too much memory");
+       return;
+   }
+
+#ifndef PNG_NO_POINTER_INDEXING
+   for (i = 0; i < new_palette.nentries; i++)
+   {
+      png_sPLT_entryp pp = new_palette.entries + i;
+
+      if (new_palette.depth == 8)
+      {
+          pp->red = *entry_start++;
+          pp->green = *entry_start++;
+          pp->blue = *entry_start++;
+          pp->alpha = *entry_start++;
+      }
+      else
+      {
+          pp->red   = png_get_uint_16(entry_start); entry_start += 2;
+          pp->green = png_get_uint_16(entry_start); entry_start += 2;
+          pp->blue  = png_get_uint_16(entry_start); entry_start += 2;
+          pp->alpha = png_get_uint_16(entry_start); entry_start += 2;
+      }
+      pp->frequency = png_get_uint_16(entry_start); entry_start += 2;
+   }
+#else
+   pp = new_palette.entries;
+   for (i = 0; i < new_palette.nentries; i++)
+   {
+
+      if (new_palette.depth == 8)
+      {
+          pp[i].red   = *entry_start++;
+          pp[i].green = *entry_start++;
+          pp[i].blue  = *entry_start++;
+          pp[i].alpha = *entry_start++;
+      }
+      else
+      {
+          pp[i].red   = png_get_uint_16(entry_start); entry_start += 2;
+          pp[i].green = png_get_uint_16(entry_start); entry_start += 2;
+          pp[i].blue  = png_get_uint_16(entry_start); entry_start += 2;
+          pp[i].alpha = png_get_uint_16(entry_start); entry_start += 2;
+      }
+      pp->frequency = png_get_uint_16(entry_start); entry_start += 2;
+   }
+#endif
+
+   /* discard all chunk data except the name and stash that */
+   new_palette.name = (png_charp)chunkdata;
+
+   png_set_sPLT(png_ptr, info_ptr, &new_palette, 1);
+
+   png_free(png_ptr, chunkdata);
+   png_free(png_ptr, new_palette.entries);
+}
+#endif /* PNG_READ_sPLT_SUPPORTED */
+
+#if defined(PNG_READ_tRNS_SUPPORTED)
+void /* PRIVATE */
+png_handle_tRNS(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+   png_byte readbuf[PNG_MAX_PALETTE_LENGTH];
+   int bit_mask;
+
+   png_debug(1, "in png_handle_tRNS\n");
+
+   /* For non-indexed color, mask off any bits in the tRNS value that
+    * exceed the bit depth.  Some creators were writing extra bits there.
+    * This is not needed for indexed color. */
+   bit_mask = (1 << png_ptr->bit_depth) - 1;
+
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Missing IHDR before tRNS");
+   else if (png_ptr->mode & PNG_HAVE_IDAT)
+   {
+      png_warning(png_ptr, "Invalid tRNS after IDAT");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tRNS))
+   {
+      png_warning(png_ptr, "Duplicate tRNS chunk");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+   if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
+   {
+      png_byte buf[2];
+
+      if (length != 2)
+      {
+         png_warning(png_ptr, "Incorrect tRNS chunk length");
+         png_crc_finish(png_ptr, length);
+         return;
+      }
+
+      png_crc_read(png_ptr, buf, 2);
+      png_ptr->num_trans = 1;
+      png_ptr->trans_values.gray = png_get_uint_16(buf) & bit_mask;
+   }
+   else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
+   {
+      png_byte buf[6];
+
+      if (length != 6)
+      {
+         png_warning(png_ptr, "Incorrect tRNS chunk length");
+         png_crc_finish(png_ptr, length);
+         return;
+      }
+      png_crc_read(png_ptr, buf, (png_size_t)length);
+      png_ptr->num_trans = 1;
+      png_ptr->trans_values.red = png_get_uint_16(buf) & bit_mask;
+      png_ptr->trans_values.green = png_get_uint_16(buf + 2) & bit_mask;
+      png_ptr->trans_values.blue = png_get_uint_16(buf + 4) & bit_mask;
+   }
+   else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+   {
+      if (!(png_ptr->mode & PNG_HAVE_PLTE))
+      {
+         /* Should be an error, but we can cope with it. */
+         png_warning(png_ptr, "Missing PLTE before tRNS");
+      }
+      if (length > (png_uint_32)png_ptr->num_palette ||
+          length > PNG_MAX_PALETTE_LENGTH)
+      {
+         png_warning(png_ptr, "Incorrect tRNS chunk length");
+         png_crc_finish(png_ptr, length);
+         return;
+      }
+      if (length == 0)
+      {
+         png_warning(png_ptr, "Zero length tRNS chunk");
+         png_crc_finish(png_ptr, length);
+         return;
+      }
+      png_crc_read(png_ptr, readbuf, (png_size_t)length);
+      png_ptr->num_trans = (png_uint_16)length;
+   }
+   else
+   {
+      png_warning(png_ptr, "tRNS chunk not allowed with alpha channel");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+   if (png_crc_finish(png_ptr, 0))
+   {
+      png_ptr->num_trans = 0;
+      return;
+   }
+
+   png_set_tRNS(png_ptr, info_ptr, readbuf, png_ptr->num_trans,
+      &(png_ptr->trans_values));
+}
+#endif
+
+#if defined(PNG_READ_bKGD_SUPPORTED)
+void /* PRIVATE */
+png_handle_bKGD(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+   png_size_t truelen;
+   png_byte buf[6];
+
+   png_debug(1, "in png_handle_bKGD\n");
+
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Missing IHDR before bKGD");
+   else if (png_ptr->mode & PNG_HAVE_IDAT)
+   {
+      png_warning(png_ptr, "Invalid bKGD after IDAT");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+   else if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE &&
+            !(png_ptr->mode & PNG_HAVE_PLTE))
+   {
+      png_warning(png_ptr, "Missing PLTE before bKGD");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_bKGD))
+   {
+      png_warning(png_ptr, "Duplicate bKGD chunk");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      truelen = 1;
+   else if (png_ptr->color_type & PNG_COLOR_MASK_COLOR)
+      truelen = 6;
+   else
+      truelen = 2;
+
+   if (length != truelen)
+   {
+      png_warning(png_ptr, "Incorrect bKGD chunk length");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+   png_crc_read(png_ptr, buf, truelen);
+   if (png_crc_finish(png_ptr, 0))
+      return;
+
+   /* We convert the index value into RGB components so that we can allow
+    * arbitrary RGB values for background when we have transparency, and
+    * so it is easy to determine the RGB values of the background color
+    * from the info_ptr struct. */
+   if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+   {
+      png_ptr->background.index = buf[0];
+      if(info_ptr->num_palette)
+      {
+          if(buf[0] > info_ptr->num_palette)
+          {
+             png_warning(png_ptr, "Incorrect bKGD chunk index value");
+             return;
+          }
+          png_ptr->background.red =
+             (png_uint_16)png_ptr->palette[buf[0]].red;
+          png_ptr->background.green =
+             (png_uint_16)png_ptr->palette[buf[0]].green;
+          png_ptr->background.blue =
+             (png_uint_16)png_ptr->palette[buf[0]].blue;
+      }
+   }
+   else if (!(png_ptr->color_type & PNG_COLOR_MASK_COLOR)) /* GRAY */
+   {
+      png_ptr->background.red =
+      png_ptr->background.green =
+      png_ptr->background.blue =
+      png_ptr->background.gray = png_get_uint_16(buf);
+   }
+   else
+   {
+      png_ptr->background.red = png_get_uint_16(buf);
+      png_ptr->background.green = png_get_uint_16(buf + 2);
+      png_ptr->background.blue = png_get_uint_16(buf + 4);
+   }
+
+   png_set_bKGD(png_ptr, info_ptr, &(png_ptr->background));
+}
+#endif
+
+#if defined(PNG_READ_hIST_SUPPORTED)
+void /* PRIVATE */
+png_handle_hIST(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+   unsigned int num, i;
+   png_uint_16 readbuf[PNG_MAX_PALETTE_LENGTH];
+
+   png_debug(1, "in png_handle_hIST\n");
+
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Missing IHDR before hIST");
+   else if (png_ptr->mode & PNG_HAVE_IDAT)
+   {
+      png_warning(png_ptr, "Invalid hIST after IDAT");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+   else if (!(png_ptr->mode & PNG_HAVE_PLTE))
+   {
+      png_warning(png_ptr, "Missing PLTE before hIST");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_hIST))
+   {
+      png_warning(png_ptr, "Duplicate hIST chunk");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+   num = length / 2 ;
+   if (num != (unsigned int) png_ptr->num_palette || num >
+      (unsigned int) PNG_MAX_PALETTE_LENGTH)
+   {
+      png_warning(png_ptr, "Incorrect hIST chunk length");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+   for (i = 0; i < num; i++)
+   {
+      png_byte buf[2];
+
+      png_crc_read(png_ptr, buf, 2);
+      readbuf[i] = png_get_uint_16(buf);
+   }
+
+   if (png_crc_finish(png_ptr, 0))
+      return;
+
+   png_set_hIST(png_ptr, info_ptr, readbuf);
+}
+#endif
+
+#if defined(PNG_READ_pHYs_SUPPORTED)
+void /* PRIVATE */
+png_handle_pHYs(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+   png_byte buf[9];
+   png_uint_32 res_x, res_y;
+   int unit_type;
+
+   png_debug(1, "in png_handle_pHYs\n");
+
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Missing IHDR before pHYs");
+   else if (png_ptr->mode & PNG_HAVE_IDAT)
+   {
+      png_warning(png_ptr, "Invalid pHYs after IDAT");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pHYs))
+   {
+      png_warning(png_ptr, "Duplicate pHYs chunk");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+   if (length != 9)
+   {
+      png_warning(png_ptr, "Incorrect pHYs chunk length");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+   png_crc_read(png_ptr, buf, 9);
+   if (png_crc_finish(png_ptr, 0))
+      return;
+
+   res_x = png_get_uint_32(buf);
+   res_y = png_get_uint_32(buf + 4);
+   unit_type = buf[8];
+   png_set_pHYs(png_ptr, info_ptr, res_x, res_y, unit_type);
+}
+#endif
+
+#if defined(PNG_READ_oFFs_SUPPORTED)
+void /* PRIVATE */
+png_handle_oFFs(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+   png_byte buf[9];
+   png_int_32 offset_x, offset_y;
+   int unit_type;
+
+   png_debug(1, "in png_handle_oFFs\n");
+
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Missing IHDR before oFFs");
+   else if (png_ptr->mode & PNG_HAVE_IDAT)
+   {
+      png_warning(png_ptr, "Invalid oFFs after IDAT");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_oFFs))
+   {
+      png_warning(png_ptr, "Duplicate oFFs chunk");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+   if (length != 9)
+   {
+      png_warning(png_ptr, "Incorrect oFFs chunk length");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+   png_crc_read(png_ptr, buf, 9);
+   if (png_crc_finish(png_ptr, 0))
+      return;
+
+   offset_x = png_get_int_32(buf);
+   offset_y = png_get_int_32(buf + 4);
+   unit_type = buf[8];
+   png_set_oFFs(png_ptr, info_ptr, offset_x, offset_y, unit_type);
+}
+#endif
+
+#if defined(PNG_READ_pCAL_SUPPORTED)
+/* read the pCAL chunk (described in the PNG Extensions document) */
+void /* PRIVATE */
+png_handle_pCAL(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+   png_charp purpose;
+   png_int_32 X0, X1;
+   png_byte type, nparams;
+   png_charp buf, units, endptr;
+   png_charpp params;
+   png_size_t slength;
+   int i;
+
+   png_debug(1, "in png_handle_pCAL\n");
+
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Missing IHDR before pCAL");
+   else if (png_ptr->mode & PNG_HAVE_IDAT)
+   {
+      png_warning(png_ptr, "Invalid pCAL after IDAT");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_pCAL))
+   {
+      png_warning(png_ptr, "Duplicate pCAL chunk");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+   png_debug1(2, "Allocating and reading pCAL chunk data (%lu bytes)\n",
+      length + 1);
+   purpose = (png_charp)png_malloc_warn(png_ptr, length + 1);
+   if (purpose == NULL)
+     {
+       png_warning(png_ptr, "No memory for pCAL purpose.");
+       return;
+     }
+   slength = (png_size_t)length;
+   png_crc_read(png_ptr, (png_bytep)purpose, slength);
+
+   if (png_crc_finish(png_ptr, 0))
+   {
+      png_free(png_ptr, purpose);
+      return;
+   }
+
+   purpose[slength] = 0x00; /* null terminate the last string */
+
+   png_debug(3, "Finding end of pCAL purpose string\n");
+   for (buf = purpose; *buf; buf++)
+      /* empty loop */ ;
+
+   endptr = purpose + slength;
+
+   /* We need to have at least 12 bytes after the purpose string
+      in order to get the parameter information. */
+   if (endptr <= buf + 12)
+   {
+      png_warning(png_ptr, "Invalid pCAL data");
+      png_free(png_ptr, purpose);
+      return;
+   }
+
+   png_debug(3, "Reading pCAL X0, X1, type, nparams, and units\n");
+   X0 = png_get_int_32((png_bytep)buf+1);
+   X1 = png_get_int_32((png_bytep)buf+5);
+   type = buf[9];
+   nparams = buf[10];
+   units = buf + 11;
+
+   png_debug(3, "Checking pCAL equation type and number of parameters\n");
+   /* Check that we have the right number of parameters for known
+      equation types. */
+   if ((type == PNG_EQUATION_LINEAR && nparams != 2) ||
+       (type == PNG_EQUATION_BASE_E && nparams != 3) ||
+       (type == PNG_EQUATION_ARBITRARY && nparams != 3) ||
+       (type == PNG_EQUATION_HYPERBOLIC && nparams != 4))
+   {
+      png_warning(png_ptr, "Invalid pCAL parameters for equation type");
+      png_free(png_ptr, purpose);
+      return;
+   }
+   else if (type >= PNG_EQUATION_LAST)
+   {
+      png_warning(png_ptr, "Unrecognized equation type for pCAL chunk");
+   }
+
+   for (buf = units; *buf; buf++)
+      /* Empty loop to move past the units string. */ ;
+
+   png_debug(3, "Allocating pCAL parameters array\n");
+   params = (png_charpp)png_malloc_warn(png_ptr, (png_uint_32)(nparams
+      *png_sizeof(png_charp))) ;
+   if (params == NULL)
+     {
+       png_free(png_ptr, purpose);
+       png_warning(png_ptr, "No memory for pCAL params.");
+       return;
+     }
+
+   /* Get pointers to the start of each parameter string. */
+   for (i = 0; i < (int)nparams; i++)
+   {
+      buf++; /* Skip the null string terminator from previous parameter. */
+
+      png_debug1(3, "Reading pCAL parameter %d\n", i);
+      for (params[i] = buf; *buf != 0x00 && buf <= endptr; buf++)
+         /* Empty loop to move past each parameter string */ ;
+
+      /* Make sure we haven't run out of data yet */
+      if (buf > endptr)
+      {
+         png_warning(png_ptr, "Invalid pCAL data");
+         png_free(png_ptr, purpose);
+         png_free(png_ptr, params);
+         return;
+      }
+   }
+
+   png_set_pCAL(png_ptr, info_ptr, purpose, X0, X1, type, nparams,
+      units, params);
+
+   png_free(png_ptr, purpose);
+   png_free(png_ptr, params);
+}
+#endif
+
+#if defined(PNG_READ_sCAL_SUPPORTED)
+/* read the sCAL chunk */
+void /* PRIVATE */
+png_handle_sCAL(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+   png_charp buffer, ep;
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+   double width, height;
+   png_charp vp;
+#else
+#ifdef PNG_FIXED_POINT_SUPPORTED
+   png_charp swidth, sheight;
+#endif
+#endif
+   png_size_t slength;
+
+   png_debug(1, "in png_handle_sCAL\n");
+
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Missing IHDR before sCAL");
+   else if (png_ptr->mode & PNG_HAVE_IDAT)
+   {
+      png_warning(png_ptr, "Invalid sCAL after IDAT");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_sCAL))
+   {
+      png_warning(png_ptr, "Duplicate sCAL chunk");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+   png_debug1(2, "Allocating and reading sCAL chunk data (%lu bytes)\n",
+      length + 1);
+   buffer = (png_charp)png_malloc_warn(png_ptr, length + 1);
+   if (buffer == NULL)
+     {
+       png_warning(png_ptr, "Out of memory while processing sCAL chunk");
+       return;
+     }
+   slength = (png_size_t)length;
+   png_crc_read(png_ptr, (png_bytep)buffer, slength);
+
+   if (png_crc_finish(png_ptr, 0))
+   {
+      png_free(png_ptr, buffer);
+      return;
+   }
+
+   buffer[slength] = 0x00; /* null terminate the last string */
+
+   ep = buffer + 1;        /* skip unit byte */
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+   width = png_strtod(png_ptr, ep, &vp);
+   if (*vp)
+   {
+       png_warning(png_ptr, "malformed width string in sCAL chunk");
+       return;
+   }
+#else
+#ifdef PNG_FIXED_POINT_SUPPORTED
+   swidth = (png_charp)png_malloc_warn(png_ptr, png_strlen(ep) + 1);
+   if (swidth == NULL)
+     {
+       png_warning(png_ptr, "Out of memory while processing sCAL chunk width");
+       return;
+     }
+   png_memcpy(swidth, ep, (png_size_t)png_strlen(ep));
+#endif
+#endif
+
+   for (ep = buffer; *ep; ep++)
+      /* empty loop */ ;
+   ep++;
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+   height = png_strtod(png_ptr, ep, &vp);
+   if (*vp)
+   {
+       png_warning(png_ptr, "malformed height string in sCAL chunk");
+       return;
+   }
+#else
+#ifdef PNG_FIXED_POINT_SUPPORTED
+   sheight = (png_charp)png_malloc_warn(png_ptr, png_strlen(ep) + 1);
+   if (swidth == NULL)
+     {
+       png_warning(png_ptr, "Out of memory while processing sCAL chunk height");
+       return;
+     }
+   png_memcpy(sheight, ep, (png_size_t)png_strlen(ep));
+#endif
+#endif
+
+   if (buffer + slength < ep
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+      || width <= 0. || height <= 0.
+#endif
+      )
+   {
+      png_warning(png_ptr, "Invalid sCAL data");
+      png_free(png_ptr, buffer);
+#if defined(PNG_FIXED_POINT_SUPPORTED) && !defined(PNG_FLOATING_POINT_SUPPORTED)
+      png_free(png_ptr, swidth);
+      png_free(png_ptr, sheight);
+#endif
+      return;
+   }
+
+
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+   png_set_sCAL(png_ptr, info_ptr, buffer[0], width, height);
+#else
+#ifdef PNG_FIXED_POINT_SUPPORTED
+   png_set_sCAL_s(png_ptr, info_ptr, buffer[0], swidth, sheight);
+#endif
+#endif
+
+   png_free(png_ptr, buffer);
+#if defined(PNG_FIXED_POINT_SUPPORTED) && !defined(PNG_FLOATING_POINT_SUPPORTED)
+   png_free(png_ptr, swidth);
+   png_free(png_ptr, sheight);
+#endif
+}
+#endif
+
+#if defined(PNG_READ_tIME_SUPPORTED)
+void /* PRIVATE */
+png_handle_tIME(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+   png_byte buf[7];
+   png_time mod_time;
+
+   png_debug(1, "in png_handle_tIME\n");
+
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Out of place tIME chunk");
+   else if (info_ptr != NULL && (info_ptr->valid & PNG_INFO_tIME))
+   {
+      png_warning(png_ptr, "Duplicate tIME chunk");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+   if (png_ptr->mode & PNG_HAVE_IDAT)
+      png_ptr->mode |= PNG_AFTER_IDAT;
+
+   if (length != 7)
+   {
+      png_warning(png_ptr, "Incorrect tIME chunk length");
+      png_crc_finish(png_ptr, length);
+      return;
+   }
+
+   png_crc_read(png_ptr, buf, 7);
+   if (png_crc_finish(png_ptr, 0))
+      return;
+
+   mod_time.second = buf[6];
+   mod_time.minute = buf[5];
+   mod_time.hour = buf[4];
+   mod_time.day = buf[3];
+   mod_time.month = buf[2];
+   mod_time.year = png_get_uint_16(buf);
+
+   png_set_tIME(png_ptr, info_ptr, &mod_time);
+}
+#endif
+
+#if defined(PNG_READ_tEXt_SUPPORTED)
+/* Note: this does not properly handle chunks that are > 64K under DOS */
+void /* PRIVATE */
+png_handle_tEXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+   png_textp text_ptr;
+   png_charp key;
+   png_charp text;
+   png_uint_32 skip = 0;
+   png_size_t slength;
+   int ret;
+
+   png_debug(1, "in png_handle_tEXt\n");
+
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Missing IHDR before tEXt");
+
+   if (png_ptr->mode & PNG_HAVE_IDAT)
+      png_ptr->mode |= PNG_AFTER_IDAT;
+
+#ifdef PNG_MAX_MALLOC_64K
+   if (length > (png_uint_32)65535L)
+   {
+      png_warning(png_ptr, "tEXt chunk too large to fit in memory");
+      skip = length - (png_uint_32)65535L;
+      length = (png_uint_32)65535L;
+   }
+#endif
+
+   key = (png_charp)png_malloc_warn(png_ptr, length + 1);
+   if (key == NULL)
+   {
+     png_warning(png_ptr, "No memory to process text chunk.");
+     return;
+   }
+   slength = (png_size_t)length;
+   png_crc_read(png_ptr, (png_bytep)key, slength);
+
+   if (png_crc_finish(png_ptr, skip))
+   {
+      png_free(png_ptr, key);
+      return;
+   }
+
+   key[slength] = 0x00;
+
+   for (text = key; *text; text++)
+      /* empty loop to find end of key */ ;
+
+   if (text != key + slength)
+      text++;
+
+   text_ptr = (png_textp)png_malloc_warn(png_ptr,
+      (png_uint_32)png_sizeof(png_text));
+   if (text_ptr == NULL)
+   {
+     png_warning(png_ptr, "Not enough memory to process text chunk.");
+     png_free(png_ptr, key);
+     return;
+   }
+   text_ptr->compression = PNG_TEXT_COMPRESSION_NONE;
+   text_ptr->key = key;
+#ifdef PNG_iTXt_SUPPORTED
+   text_ptr->lang = NULL;
+   text_ptr->lang_key = NULL;
+   text_ptr->itxt_length = 0;
+#endif
+   text_ptr->text = text;
+   text_ptr->text_length = png_strlen(text);
+
+   ret=png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
+
+   png_free(png_ptr, key);
+   png_free(png_ptr, text_ptr);
+   if (ret)
+     png_warning(png_ptr, "Insufficient memory to process text chunk.");
+}
+#endif
+
+#if defined(PNG_READ_zTXt_SUPPORTED)
+/* note: this does not correctly handle chunks that are > 64K under DOS */
+void /* PRIVATE */
+png_handle_zTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+   png_textp text_ptr;
+   png_charp chunkdata;
+   png_charp text;
+   int comp_type;
+   int ret;
+   png_size_t slength, prefix_len, data_len;
+
+   png_debug(1, "in png_handle_zTXt\n");
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Missing IHDR before zTXt");
+
+   if (png_ptr->mode & PNG_HAVE_IDAT)
+      png_ptr->mode |= PNG_AFTER_IDAT;
+
+#ifdef PNG_MAX_MALLOC_64K
+   /* We will no doubt have problems with chunks even half this size, but
+      there is no hard and fast rule to tell us where to stop. */
+   if (length > (png_uint_32)65535L)
+   {
+     png_warning(png_ptr,"zTXt chunk too large to fit in memory");
+     png_crc_finish(png_ptr, length);
+     return;
+   }
+#endif
+
+   chunkdata = (png_charp)png_malloc_warn(png_ptr, length + 1);
+   if (chunkdata == NULL)
+   {
+     png_warning(png_ptr,"Out of memory processing zTXt chunk.");
+     return;
+   }
+   slength = (png_size_t)length;
+   png_crc_read(png_ptr, (png_bytep)chunkdata, slength);
+   if (png_crc_finish(png_ptr, 0))
+   {
+      png_free(png_ptr, chunkdata);
+      return;
+   }
+
+   chunkdata[slength] = 0x00;
+
+   for (text = chunkdata; *text; text++)
+      /* empty loop */ ;
+
+   /* zTXt must have some text after the chunkdataword */
+   if (text == chunkdata + slength - 1)
+   {
+      png_warning(png_ptr, "Truncated zTXt chunk");
+      png_free(png_ptr, chunkdata);
+      return;
+   }
+   else
+   {
+       comp_type = *(++text);
+       if (comp_type != PNG_TEXT_COMPRESSION_zTXt)
+       {
+          png_warning(png_ptr, "Unknown compression type in zTXt chunk");
+          comp_type = PNG_TEXT_COMPRESSION_zTXt;
+       }
+       text++;        /* skip the compression_method byte */
+   }
+   prefix_len = text - chunkdata;
+
+   chunkdata = (png_charp)png_decompress_chunk(png_ptr, comp_type, chunkdata,
+                                    (png_size_t)length, prefix_len, &data_len);
+
+   text_ptr = (png_textp)png_malloc_warn(png_ptr,
+     (png_uint_32)png_sizeof(png_text));
+   if (text_ptr == NULL)
+   {
+     png_warning(png_ptr,"Not enough memory to process zTXt chunk.");
+     png_free(png_ptr, chunkdata);
+     return;
+   }
+   text_ptr->compression = comp_type;
+   text_ptr->key = chunkdata;
+#ifdef PNG_iTXt_SUPPORTED
+   text_ptr->lang = NULL;
+   text_ptr->lang_key = NULL;
+   text_ptr->itxt_length = 0;
+#endif
+   text_ptr->text = chunkdata + prefix_len;
+   text_ptr->text_length = data_len;
+
+   ret=png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
+
+   png_free(png_ptr, text_ptr);
+   png_free(png_ptr, chunkdata);
+   if (ret)
+     png_error(png_ptr, "Insufficient memory to store zTXt chunk.");
+}
+#endif
+
+#if defined(PNG_READ_iTXt_SUPPORTED)
+/* note: this does not correctly handle chunks that are > 64K under DOS */
+void /* PRIVATE */
+png_handle_iTXt(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+   png_textp text_ptr;
+   png_charp chunkdata;
+   png_charp key, lang, text, lang_key;
+   int comp_flag;
+   int comp_type = 0;
+   int ret;
+   png_size_t slength, prefix_len, data_len;
+
+   png_debug(1, "in png_handle_iTXt\n");
+
+   if (!(png_ptr->mode & PNG_HAVE_IHDR))
+      png_error(png_ptr, "Missing IHDR before iTXt");
+
+   if (png_ptr->mode & PNG_HAVE_IDAT)
+      png_ptr->mode |= PNG_AFTER_IDAT;
+
+#ifdef PNG_MAX_MALLOC_64K
+   /* We will no doubt have problems with chunks even half this size, but
+      there is no hard and fast rule to tell us where to stop. */
+   if (length > (png_uint_32)65535L)
+   {
+     png_warning(png_ptr,"iTXt chunk too large to fit in memory");
+     png_crc_finish(png_ptr, length);
+     return;
+   }
+#endif
+
+   chunkdata = (png_charp)png_malloc_warn(png_ptr, length + 1);
+   if (chunkdata == NULL)
+   {
+     png_warning(png_ptr, "No memory to process iTXt chunk.");
+     return;
+   }
+   slength = (png_size_t)length;
+   png_crc_read(png_ptr, (png_bytep)chunkdata, slength);
+   if (png_crc_finish(png_ptr, 0))
+   {
+      png_free(png_ptr, chunkdata);
+      return;
+   }
+
+   chunkdata[slength] = 0x00;
+
+   for (lang = chunkdata; *lang; lang++)
+      /* empty loop */ ;
+   lang++;        /* skip NUL separator */
+
+   /* iTXt must have a language tag (possibly empty), two compression bytes,
+      translated keyword (possibly empty), and possibly some text after the
+      keyword */
+
+   if (lang >= chunkdata + slength - 3)
+   {
+      png_warning(png_ptr, "Truncated iTXt chunk");
+      png_free(png_ptr, chunkdata);
+      return;
+   }
+   else
+   {
+       comp_flag = *lang++;
+       comp_type = *lang++;
+   }
+
+   for (lang_key = lang; *lang_key; lang_key++)
+      /* empty loop */ ;
+   lang_key++;        /* skip NUL separator */
+
+   for (text = lang_key; *text; text++)
+      /* empty loop */ ;
+   text++;        /* skip NUL separator */
+   if (text >= chunkdata + slength)
+   {
+      png_warning(png_ptr, "Malformed iTXt chunk");
+      png_free(png_ptr, chunkdata);
+      return;
+   }
+
+   prefix_len = text - chunkdata;
+
+   key=chunkdata;
+   if (comp_flag)
+       chunkdata = png_decompress_chunk(png_ptr, comp_type, chunkdata,
+          (size_t)length, prefix_len, &data_len);
+   else
+       data_len=png_strlen(chunkdata + prefix_len);
+   text_ptr = (png_textp)png_malloc_warn(png_ptr,
+      (png_uint_32)png_sizeof(png_text));
+   if (text_ptr == NULL)
+   {
+     png_warning(png_ptr,"Not enough memory to process iTXt chunk.");
+     png_free(png_ptr, chunkdata);
+     return;
+   }
+   text_ptr->compression = (int)comp_flag + 1;
+   text_ptr->lang_key = chunkdata+(lang_key-key);
+   text_ptr->lang = chunkdata+(lang-key);
+   text_ptr->itxt_length = data_len;
+   text_ptr->text_length = 0;
+   text_ptr->key = chunkdata;
+   text_ptr->text = chunkdata + prefix_len;
+
+   ret=png_set_text_2(png_ptr, info_ptr, text_ptr, 1);
+
+   png_free(png_ptr, text_ptr);
+   png_free(png_ptr, chunkdata);
+   if (ret)
+     png_error(png_ptr, "Insufficient memory to store iTXt chunk.");
+}
+#endif
+
+/* This function is called when we haven't found a handler for a
+   chunk.  If there isn't a problem with the chunk itself (ie bad
+   chunk name, CRC, or a critical chunk), the chunk is silently ignored
+   -- unless the PNG_FLAG_UNKNOWN_CHUNKS_SUPPORTED flag is on in which
+   case it will be saved away to be written out later. */
+void /* PRIVATE */
+png_handle_unknown(png_structp png_ptr, png_infop info_ptr, png_uint_32 length)
+{
+   png_uint_32 skip = 0;
+
+   png_debug(1, "in png_handle_unknown\n");
+
+   if (png_ptr->mode & PNG_HAVE_IDAT)
+   {
+#ifdef PNG_USE_LOCAL_ARRAYS
+      PNG_CONST PNG_IDAT;
+#endif
+      if (png_memcmp(png_ptr->chunk_name, png_IDAT, 4))  /* not an IDAT */
+         png_ptr->mode |= PNG_AFTER_IDAT;
+   }
+
+   png_check_chunk_name(png_ptr, png_ptr->chunk_name);
+
+   if (!(png_ptr->chunk_name[0] & 0x20))
+   {
+#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
+      if(png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
+           PNG_HANDLE_CHUNK_ALWAYS
+#if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
+           && png_ptr->read_user_chunk_fn == NULL
+#endif
+        )
+#endif
+          png_chunk_error(png_ptr, "unknown critical chunk");
+   }
+
+#if defined(PNG_READ_UNKNOWN_CHUNKS_SUPPORTED)
+   if ((png_ptr->flags & PNG_FLAG_KEEP_UNKNOWN_CHUNKS) ||
+       (png_ptr->read_user_chunk_fn != NULL))
+   {
+#ifdef PNG_MAX_MALLOC_64K
+       if (length > (png_uint_32)65535L)
+       {
+           png_warning(png_ptr, "unknown chunk too large to fit in memory");
+           skip = length - (png_uint_32)65535L;
+           length = (png_uint_32)65535L;
+       }
+#endif
+       png_strncpy((png_charp)png_ptr->unknown_chunk.name,
+	 (png_charp)png_ptr->chunk_name,
+         png_sizeof((png_charp)png_ptr->chunk_name));
+       png_ptr->unknown_chunk.data = (png_bytep)png_malloc(png_ptr, length);
+       png_ptr->unknown_chunk.size = (png_size_t)length;
+       png_crc_read(png_ptr, (png_bytep)png_ptr->unknown_chunk.data, length);
+#if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
+       if(png_ptr->read_user_chunk_fn != NULL)
+       {
+          /* callback to user unknown chunk handler */
+          int ret;
+          ret = (*(png_ptr->read_user_chunk_fn))
+            (png_ptr, &png_ptr->unknown_chunk);
+          if (ret < 0)
+             png_chunk_error(png_ptr, "error in user chunk");
+          if (ret == 0)
+          {
+             if (!(png_ptr->chunk_name[0] & 0x20))
+                if(png_handle_as_unknown(png_ptr, png_ptr->chunk_name) !=
+                     PNG_HANDLE_CHUNK_ALWAYS)
+                   png_chunk_error(png_ptr, "unknown critical chunk");
+             png_set_unknown_chunks(png_ptr, info_ptr,
+               &png_ptr->unknown_chunk, 1);
+          }
+       }
+#else
+       png_set_unknown_chunks(png_ptr, info_ptr, &png_ptr->unknown_chunk, 1);
+#endif
+       png_free(png_ptr, png_ptr->unknown_chunk.data);
+       png_ptr->unknown_chunk.data = NULL;
+   }
+   else
+#endif
+      skip = length;
+
+   png_crc_finish(png_ptr, skip);
+
+#if !defined(PNG_READ_USER_CHUNKS_SUPPORTED)
+   info_ptr = info_ptr; /* quiet compiler warnings about unused info_ptr */
+#endif
+}
+
+/* This function is called to verify that a chunk name is valid.
+   This function can't have the "critical chunk check" incorporated
+   into it, since in the future we will need to be able to call user
+   functions to handle unknown critical chunks after we check that
+   the chunk name itself is valid. */
+
+#define isnonalpha(c) ((c) < 65 || (c) > 122 || ((c) > 90 && (c) < 97))
+
+void /* PRIVATE */
+png_check_chunk_name(png_structp png_ptr, png_bytep chunk_name)
+{
+   png_debug(1, "in png_check_chunk_name\n");
+   if (isnonalpha(chunk_name[0]) || isnonalpha(chunk_name[1]) ||
+       isnonalpha(chunk_name[2]) || isnonalpha(chunk_name[3]))
+   {
+      png_chunk_error(png_ptr, "invalid chunk type");
+   }
+}
+
+/* Combines the row recently read in with the existing pixels in the
+   row.  This routine takes care of alpha and transparency if requested.
+   This routine also handles the two methods of progressive display
+   of interlaced images, depending on the mask value.
+   The mask value describes which pixels are to be combined with
+   the row.  The pattern always repeats every 8 pixels, so just 8
+   bits are needed.  A one indicates the pixel is to be combined,
+   a zero indicates the pixel is to be skipped.  This is in addition
+   to any alpha or transparency value associated with the pixel.  If
+   you want all pixels to be combined, pass 0xff (255) in mask.  */
+
+/* Optimized C version of utilities to read a PNG file
+ *
+ * Based on code contributed by Nirav Chhatrapati, Intel Corp., 1998.
+ * Interface to libpng contributed by Gilles Vollant, 1999.
+ * GNU C port by Greg Roelofs, 1999-2001.
+ *
+ */
+
+#if defined(PNG_OPTIMIZED_CODE_SUPPORTED)
+#if !defined(PNG_HAVE_MMX_COMBINE_ROW)
+
+/*===========================================================================*/
+/*                                                                           */
+/*                       P N G _ C O M B I N E _ R O W                       */
+/*                                                                           */
+/*===========================================================================*/
+
+
+#define BPP2  2
+#define BPP3  3 /* bytes per pixel (a.k.a. pixel_bytes) */
+#define BPP4  4
+#define BPP6  6 /* (defined only to help avoid cut-and-paste errors) */
+#define BPP8  8
+
+/* Combines the row recently read in with the previous row.
+   This routine takes care of alpha and transparency if requested.
+   This routine also handles the two methods of progressive display
+   of interlaced images, depending on the mask value.
+   The mask value describes which pixels are to be combined with
+   the row.  The pattern always repeats every 8 pixels, so just 8
+   bits are needed.  A one indicates the pixel is to be combined; a
+   zero indicates the pixel is to be skipped.  This is in addition
+   to any alpha or transparency value associated with the pixel.
+   If you want all pixels to be combined, pass 0xff (255) in mask. */
+
+/* Use this routine for the x86 platform - it uses a faster MMX routine
+   if the machine supports MMX. */
+
+void /* PRIVATE */
+png_combine_row(png_structp png_ptr, png_bytep row, int mask)
+{
+
+#if defined(PNG_USE_LOCAL_ARRAYS)
+static PNG_CONST int FARDATA png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+static PNG_CONST int FARDATA png_pass_inc[7]   = {8, 8, 4, 4, 2, 2, 1};
+static PNG_CONST int FARDATA png_pass_width[7] = {8, 4, 4, 2, 2, 1, 1};
+#endif
+
+   png_debug(1, "in png_combine_row (pngrutil.c OPTIMIZED)\n");
+
+   if (mask == 0xff)
+   {
+      png_debug(2,"mask == 0xff:  doing single png_memcpy()\n");
+      png_memcpy(row, png_ptr->row_buf + 1,
+       (png_size_t)PNG_ROWBYTES(png_ptr->row_info.pixel_depth,png_ptr->width));
+   }
+   else   /* (png_combine_row() is never called with mask == 0) */
+   {
+      switch (png_ptr->row_info.pixel_depth)
+      {
+         /* most common case:  combining 24-bit RGB */
+         case 24:       /* png_ptr->row_info.pixel_depth */
+         {
+            png_bytep srcptr;
+            png_bytep dstptr;
+
+            {
+               register png_uint_32 i;
+               png_uint_32 initial_val = BPP3 * png_pass_start[png_ptr->pass];
+                 /* png.c:  png_pass_start[] = {0, 4, 0, 2, 0, 1, 0}; */
+               register int stride = BPP3 * png_pass_inc[png_ptr->pass];
+                 /* png.c:  png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1}; */
+               register int rep_bytes = BPP3 * png_pass_width[png_ptr->pass];
+                 /* png.c:  png_pass_width[] = {8, 4, 4, 2, 2, 1, 1}; */
+               png_uint_32 len = png_ptr->width &~7; /* reduce to mult of 8 */
+               int diff = (int) (png_ptr->width & 7); /* amount lost */
+               register png_uint_32 final_val = BPP3 * len;   /* GRR bugfix */
+
+               srcptr = png_ptr->row_buf + 1 + initial_val;
+               dstptr = row + initial_val;
+
+               for (i = initial_val; i < final_val; i += stride)
+               {
+                  png_memcpy(dstptr, srcptr, rep_bytes);
+                  srcptr += stride;
+                  dstptr += stride;
+               }
+               if (diff)  /* number of leftover pixels:  3 for pngtest */
+               {
+                  final_val += diff*BPP3;
+                  for (; i < final_val; i += stride)
+                  {
+                     if (rep_bytes > (int)(final_val-i))
+                        rep_bytes = (int)(final_val-i);
+                     png_memcpy(dstptr, srcptr, rep_bytes);
+                     srcptr += stride;
+                     dstptr += stride;
+                  }
+               }
+            } /* end of else (_mmx_supported) */
+
+            break;
+         }       /* end 24 bpp */
+
+         case 32:       /* png_ptr->row_info.pixel_depth */
+         {
+            png_bytep srcptr;
+            png_bytep dstptr;
+
+            {
+               register png_uint_32 i;
+               png_uint_32 initial_val = BPP4 * png_pass_start[png_ptr->pass];
+                 /* png.c:  png_pass_start[] = {0, 4, 0, 2, 0, 1, 0}; */
+               register int stride = BPP4 * png_pass_inc[png_ptr->pass];
+                 /* png.c:  png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1}; */
+               register int rep_bytes = BPP4 * png_pass_width[png_ptr->pass];
+                 /* png.c:  png_pass_width[] = {8, 4, 4, 2, 2, 1, 1}; */
+               png_uint_32 len = png_ptr->width &~7; /* reduce to mult of 8 */
+               int diff = (int) (png_ptr->width & 7); /* amount lost */
+               register png_uint_32 final_val = BPP4 * len;   /* GRR bugfix */
+
+               srcptr = png_ptr->row_buf + 1 + initial_val;
+               dstptr = row + initial_val;
+
+               for (i = initial_val; i < final_val; i += stride)
+               {
+                  png_memcpy(dstptr, srcptr, rep_bytes);
+                  srcptr += stride;
+                  dstptr += stride;
+               }
+               if (diff)  /* number of leftover pixels:  3 for pngtest */
+               {
+                  final_val += diff*BPP4;
+                  for (; i < final_val; i += stride)
+                  {
+                     if (rep_bytes > (int)(final_val-i))
+                        rep_bytes = (int)(final_val-i);
+                     png_memcpy(dstptr, srcptr, rep_bytes);
+                     srcptr += stride;
+                     dstptr += stride;
+                  }
+               }
+            }
+
+            break;
+         }       /* end 32 bpp */
+
+         case 8:        /* png_ptr->row_info.pixel_depth */
+         {
+            png_bytep srcptr;
+            png_bytep dstptr;
+            {
+               register png_uint_32 i;
+               png_uint_32 initial_val = png_pass_start[png_ptr->pass];
+                 /* png.c:  png_pass_start[] = {0, 4, 0, 2, 0, 1, 0}; */
+               register int stride = png_pass_inc[png_ptr->pass];
+                 /* png.c:  png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1}; */
+               register int rep_bytes = png_pass_width[png_ptr->pass];
+                 /* png.c:  png_pass_width[] = {8, 4, 4, 2, 2, 1, 1}; */
+               png_uint_32 len = png_ptr->width &~7; /* reduce to mult of 8 */
+               int diff = (int) (png_ptr->width & 7); /* amount lost */
+               register png_uint_32 final_val = len;  /* GRR bugfix */
+
+               srcptr = png_ptr->row_buf + 1 + initial_val;
+               dstptr = row + initial_val;
+
+               for (i = initial_val; i < final_val; i += stride)
+               {
+                  png_memcpy(dstptr, srcptr, rep_bytes);
+                  srcptr += stride;
+                  dstptr += stride;
+               }
+               if (diff)  /* number of leftover pixels:  3 for pngtest */
+               {
+                  final_val += diff /* *BPP1 */ ;
+                  for (; i < final_val; i += stride)
+                  {
+                     if (rep_bytes > (int)(final_val-i))
+                        rep_bytes = (int)(final_val-i);
+                     png_memcpy(dstptr, srcptr, rep_bytes);
+                     srcptr += stride;
+                     dstptr += stride;
+                  }
+               }
+            }
+
+            break;
+         }       /* end 8 bpp */
+
+         case 1:        /* png_ptr->row_info.pixel_depth */
+         {
+            png_bytep sp;
+            png_bytep dp;
+            int s_inc, s_start, s_end;
+            int m;
+            int shift;
+            png_uint_32 i;
+
+            sp = png_ptr->row_buf + 1;
+            dp = row;
+            m = 0x80;
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+            if (png_ptr->transformations & PNG_PACKSWAP)
+            {
+                s_start = 0;
+                s_end = 7;
+                s_inc = 1;
+            }
+            else
+#endif
+            {
+                s_start = 7;
+                s_end = 0;
+                s_inc = -1;
+            }
+
+            shift = s_start;
+
+            for (i = 0; i < png_ptr->width; i++)
+            {
+               if (m & mask)
+               {
+                  int value;
+
+                  value = (*sp >> shift) & 0x1;
+                  *dp &= (png_byte)((0x7f7f >> (7 - shift)) & 0xff);
+                  *dp |= (png_byte)(value << shift);
+               }
+
+               if (shift == s_end)
+               {
+                  shift = s_start;
+                  sp++;
+                  dp++;
+               }
+               else
+                  shift += s_inc;
+
+               if (m == 1)
+                  m = 0x80;
+               else
+                  m >>= 1;
+            }
+            break;
+         }       /* end 1 bpp */
+
+         case 2:        /* png_ptr->row_info.pixel_depth */
+         {
+            png_bytep sp;
+            png_bytep dp;
+            int s_start, s_end, s_inc;
+            int m;
+            int shift;
+            png_uint_32 i;
+            int value;
+
+            sp = png_ptr->row_buf + 1;
+            dp = row;
+            m = 0x80;
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+            if (png_ptr->transformations & PNG_PACKSWAP)
+            {
+               s_start = 0;
+               s_end = 6;
+               s_inc = 2;
+            }
+            else
+#endif
+            {
+               s_start = 6;
+               s_end = 0;
+               s_inc = -2;
+            }
+
+            shift = s_start;
+
+            for (i = 0; i < png_ptr->width; i++)
+            {
+               if (m & mask)
+               {
+                  value = (*sp >> shift) & 0x3;
+                  *dp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
+                  *dp |= (png_byte)(value << shift);
+               }
+
+               if (shift == s_end)
+               {
+                  shift = s_start;
+                  sp++;
+                  dp++;
+               }
+               else
+                  shift += s_inc;
+               if (m == 1)
+                  m = 0x80;
+               else
+                  m >>= 1;
+            }
+            break;
+         }       /* end 2 bpp */
+
+         case 4:        /* png_ptr->row_info.pixel_depth */
+         {
+            png_bytep sp;
+            png_bytep dp;
+            int s_start, s_end, s_inc;
+            int m;
+            int shift;
+            png_uint_32 i;
+            int value;
+
+            sp = png_ptr->row_buf + 1;
+            dp = row;
+            m = 0x80;
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+            if (png_ptr->transformations & PNG_PACKSWAP)
+            {
+               s_start = 0;
+               s_end = 4;
+               s_inc = 4;
+            }
+            else
+#endif
+            {
+               s_start = 4;
+               s_end = 0;
+               s_inc = -4;
+            }
+            shift = s_start;
+
+            for (i = 0; i < png_ptr->width; i++)
+            {
+               if (m & mask)
+               {
+                  value = (*sp >> shift) & 0xf;
+                  *dp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
+                  *dp |= (png_byte)(value << shift);
+               }
+
+               if (shift == s_end)
+               {
+                  shift = s_start;
+                  sp++;
+                  dp++;
+               }
+               else
+                  shift += s_inc;
+               if (m == 1)
+                  m = 0x80;
+               else
+                  m >>= 1;
+            }
+            break;
+         }       /* end 4 bpp */
+
+         case 16:       /* png_ptr->row_info.pixel_depth */
+         {
+            png_bytep srcptr;
+            png_bytep dstptr;
+
+            {
+               register png_uint_32 i;
+               png_uint_32 initial_val = BPP2 * png_pass_start[png_ptr->pass];
+                 /* png.c:  png_pass_start[] = {0, 4, 0, 2, 0, 1, 0}; */
+               register int stride = BPP2 * png_pass_inc[png_ptr->pass];
+                 /* png.c:  png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1}; */
+               register int rep_bytes = BPP2 * png_pass_width[png_ptr->pass];
+                 /* png.c:  png_pass_width[] = {8, 4, 4, 2, 2, 1, 1}; */
+               png_uint_32 len = png_ptr->width &~7;  /* reduce to mult of 8 */
+               int diff = (int) (png_ptr->width & 7); /* amount lost */
+               register png_uint_32 final_val = BPP2 * len;   /* GRR bugfix */
+
+               srcptr = png_ptr->row_buf + 1 + initial_val;
+               dstptr = row + initial_val;
+
+               for (i = initial_val; i < final_val; i += stride)
+               {
+                  png_memcpy(dstptr, srcptr, rep_bytes);
+                  srcptr += stride;
+                  dstptr += stride;
+               }
+               if (diff)  /* number of leftover pixels:  3 for pngtest */
+               {
+                  final_val += diff*BPP2;
+                  for (; i < final_val; i += stride)
+                  {
+                     if (rep_bytes > (int)(final_val-i))
+                        rep_bytes = (int)(final_val-i);
+                     png_memcpy(dstptr, srcptr, rep_bytes);
+                     srcptr += stride;
+                     dstptr += stride;
+                  }
+               }
+            } /* end of else (_mmx_supported) */
+
+            break;
+         }       /* end 16 bpp */
+
+
+
+         case 48:       /* png_ptr->row_info.pixel_depth */
+         {
+            png_bytep srcptr;
+            png_bytep dstptr;
+            {
+               register png_uint_32 i;
+               png_uint_32 initial_val = BPP6 * png_pass_start[png_ptr->pass];
+                 /* png.c:  png_pass_start[] = {0, 4, 0, 2, 0, 1, 0}; */
+               register int stride = BPP6 * png_pass_inc[png_ptr->pass];
+                 /* png.c:  png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1}; */
+               register int rep_bytes = BPP6 * png_pass_width[png_ptr->pass];
+                 /* png.c:  png_pass_width[] = {8, 4, 4, 2, 2, 1, 1}; */
+               png_uint_32 len = png_ptr->width &~7; /* reduce to mult of 8 */
+               int diff = (int) (png_ptr->width & 7); /* amount lost */
+               register png_uint_32 final_val = BPP6 * len;   /* GRR bugfix */
+
+               srcptr = png_ptr->row_buf + 1 + initial_val;
+               dstptr = row + initial_val;
+
+               for (i = initial_val; i < final_val; i += stride)
+               {
+                  png_memcpy(dstptr, srcptr, rep_bytes);
+                  srcptr += stride;
+                  dstptr += stride;
+               }
+               if (diff)  /* number of leftover pixels:  3 for pngtest */
+               {
+                  final_val += diff*BPP6;
+                  for (; i < final_val; i += stride)
+                  {
+                     if (rep_bytes > (int)(final_val-i))
+                        rep_bytes = (int)(final_val-i);
+                     png_memcpy(dstptr, srcptr, rep_bytes);
+                     srcptr += stride;
+                     dstptr += stride;
+                  }
+               }
+            }
+            break;
+         }       /* end 48 bpp */
+
+         case 64:       /* png_ptr->row_info.pixel_depth */
+         {
+            png_bytep srcptr;
+            png_bytep dstptr;
+            register png_uint_32 i;
+            png_uint_32 initial_val = BPP8 * png_pass_start[png_ptr->pass];
+              /* png.c:  png_pass_start[] = {0, 4, 0, 2, 0, 1, 0}; */
+            register int stride = BPP8 * png_pass_inc[png_ptr->pass];
+              /* png.c:  png_pass_inc[] = {8, 8, 4, 4, 2, 2, 1}; */
+            register int rep_bytes = BPP8 * png_pass_width[png_ptr->pass];
+              /* png.c:  png_pass_width[] = {8, 4, 4, 2, 2, 1, 1}; */
+            png_uint_32 len = png_ptr->width &~7;  /* reduce to mult of 8 */
+            int diff = (int) (png_ptr->width & 7); /* amount lost */
+            register png_uint_32 final_val = BPP8 * len;   /* GRR bugfix */
+
+            srcptr = png_ptr->row_buf + 1 + initial_val;
+            dstptr = row + initial_val;
+
+            for (i = initial_val; i < final_val; i += stride)
+            {
+               png_memcpy(dstptr, srcptr, rep_bytes);
+               srcptr += stride;
+               dstptr += stride;
+            }
+            if (diff)  /* number of leftover pixels:  3 for pngtest */
+            {
+               final_val += diff*BPP8;
+               for (; i < final_val; i += stride)
+               {
+                  if (rep_bytes > (int)(final_val-i))
+                     rep_bytes = (int)(final_val-i);
+                  png_memcpy(dstptr, srcptr, rep_bytes);
+                  srcptr += stride;
+                  dstptr += stride;
+               }
+            }
+
+            break;
+         }       /* end 64 bpp */
+
+         default: /* png_ptr->row_info.pixel_depth != 1,2,4,8,16,24,32,48,64 */
+         {
+            /* this should never happen */
+            png_warning(png_ptr, "Invalid row_info.pixel_depth in pngrutil");
+            break;
+         }
+      } /* end switch (png_ptr->row_info.pixel_depth) */
+
+   } /* end if (non-trivial mask) */
+
+} /* end png_combine_row() */
+#endif /* PNG_HAVE_MMX_COMBINE_ROW */
+
+
+
+/*===========================================================================*/
+/*                                                                           */
+/*                 P N G _ D O _ R E A D _ I N T E R L A C E                 */
+/*                                                                           */
+/*===========================================================================*/
+
+#if defined(PNG_READ_INTERLACING_SUPPORTED)
+#if !defined(PNG_HAVE_MMX_READ_INTERLACE)
+
+/* png_do_read_interlace() is called after any 16-bit to 8-bit conversion
+ * has taken place.  [GRR: what other steps come before and/or after?]
+ */
+
+void /* PRIVATE */
+png_do_read_interlace(png_structp png_ptr)
+{
+#if defined(PNG_USE_LOCAL_ARRAYS)
+static PNG_CONST int FARDATA png_pass_inc[7]   = {8, 8, 4, 4, 2, 2, 1};
+#endif
+   png_row_infop row_info = &(png_ptr->row_info);
+   png_bytep row = png_ptr->row_buf + 1;
+   int pass = png_ptr->pass;
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+   png_uint_32 transformations = png_ptr->transformations;
+#endif
+   png_debug(1,"in png_do_read_interlace (pngrutil.c OPTIMIZED)\n");
+
+   if (row != NULL && row_info != NULL)
+   {
+      png_uint_32 final_width;
+
+      final_width = row_info->width * png_pass_inc[pass];
+
+      switch (row_info->pixel_depth)
+      {
+         case 1:
+         {
+            png_bytep sp, dp;
+            int sshift, dshift;
+            int s_start, s_end, s_inc;
+            png_byte v;
+            png_uint_32 i;
+            int j;
+
+            sp = row + (png_size_t)((row_info->width - 1) >> 3);
+            dp = row + (png_size_t)((final_width - 1) >> 3);
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+            if (transformations & PNG_PACKSWAP)
+            {
+               sshift = (int)((row_info->width + 7) & 7);
+               dshift = (int)((final_width + 7) & 7);
+               s_start = 7;
+               s_end = 0;
+               s_inc = -1;
+            }
+            else
+#endif
+            {
+               sshift = 7 - (int)((row_info->width + 7) & 7);
+               dshift = 7 - (int)((final_width + 7) & 7);
+               s_start = 0;
+               s_end = 7;
+               s_inc = 1;
+            }
+
+            for (i = row_info->width; i; i--)
+            {
+               v = (png_byte)((*sp >> sshift) & 0x1);
+               for (j = 0; j < png_pass_inc[pass]; j++)
+               {
+                  *dp &= (png_byte)((0x7f7f >> (7 - dshift)) & 0xff);
+                  *dp |= (png_byte)(v << dshift);
+                  if (dshift == s_end)
+                  {
+                     dshift = s_start;
+                     dp--;
+                  }
+                  else
+                     dshift += s_inc;
+               }
+               if (sshift == s_end)
+               {
+                  sshift = s_start;
+                  sp--;
+               }
+               else
+                  sshift += s_inc;
+            }
+            break;
+         }
+
+         case 2:
+         {
+            png_bytep sp, dp;
+            int sshift, dshift;
+            int s_start, s_end, s_inc;
+            png_uint_32 i;
+
+            sp = row + (png_size_t)((row_info->width - 1) >> 2);
+            dp = row + (png_size_t)((final_width - 1) >> 2);
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+            if (transformations & PNG_PACKSWAP)
+            {
+               sshift = (png_size_t)(((row_info->width + 3) & 3) << 1);
+               dshift = (png_size_t)(((final_width + 3) & 3) << 1);
+               s_start = 6;
+               s_end = 0;
+               s_inc = -2;
+            }
+            else
+#endif
+            {
+               sshift = (png_size_t)((3 - ((row_info->width + 3) & 3)) << 1);
+               dshift = (png_size_t)((3 - ((final_width + 3) & 3)) << 1);
+               s_start = 0;
+               s_end = 6;
+               s_inc = 2;
+            }
+
+            for (i = row_info->width; i; i--)
+            {
+               png_byte v;
+               int j;
+
+               v = (png_byte)((*sp >> sshift) & 0x3);
+               for (j = 0; j < png_pass_inc[pass]; j++)
+               {
+                  *dp &= (png_byte)((0x3f3f >> (6 - dshift)) & 0xff);
+                  *dp |= (png_byte)(v << dshift);
+                  if (dshift == s_end)
+                  {
+                     dshift = s_start;
+                     dp--;
+                  }
+                  else
+                     dshift += s_inc;
+               }
+               if (sshift == s_end)
+               {
+                  sshift = s_start;
+                  sp--;
+               }
+               else
+                  sshift += s_inc;
+            }
+            break;
+         }
+
+         case 4:
+         {
+            png_bytep sp, dp;
+            int sshift, dshift;
+            int s_start, s_end, s_inc;
+            png_uint_32 i;
+
+            sp = row + (png_size_t)((row_info->width - 1) >> 1);
+            dp = row + (png_size_t)((final_width - 1) >> 1);
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+            if (transformations & PNG_PACKSWAP)
+            {
+               sshift = (png_size_t)(((row_info->width + 1) & 1) << 2);
+               dshift = (png_size_t)(((final_width + 1) & 1) << 2);
+               s_start = 4;
+               s_end = 0;
+               s_inc = -4;
+            }
+            else
+#endif
+            {
+               sshift = (png_size_t)((1 - ((row_info->width + 1) & 1)) << 2);
+               dshift = (png_size_t)((1 - ((final_width + 1) & 1)) << 2);
+               s_start = 0;
+               s_end = 4;
+               s_inc = 4;
+            }
+
+            for (i = row_info->width; i; i--)
+            {
+               png_byte v;
+               int j;
+
+               v = (png_byte)((*sp >> sshift) & 0xf);
+               for (j = 0; j < png_pass_inc[pass]; j++)
+               {
+                  *dp &= (png_byte)((0xf0f >> (4 - dshift)) & 0xff);
+                  *dp |= (png_byte)(v << dshift);
+                  if (dshift == s_end)
+                  {
+                     dshift = s_start;
+                     dp--;
+                  }
+                  else
+                     dshift += s_inc;
+               }
+               if (sshift == s_end)
+               {
+                  sshift = s_start;
+                  sp--;
+               }
+               else
+                  sshift += s_inc;
+            }
+            break;
+         }
+
+       /*====================================================================*/
+
+         default: /* 8-bit or larger (this is where the routine is modified) */
+         {
+            png_bytep sptr, dp;
+            png_uint_32 i;
+            png_size_t pixel_bytes;
+            int width = (int)row_info->width;
+
+            pixel_bytes = (row_info->pixel_depth >> 3);
+
+            /* point sptr at the last pixel in the pre-expanded row: */
+            sptr = row + (width - 1) * pixel_bytes;
+
+            /* point dp at the last pixel position in the expanded row: */
+            dp = row + (final_width - 1) * pixel_bytes;
+
+            /* MMX not supported:  use modified C code - takes advantage
+             *   of inlining of png_memcpy for a constant */
+            /* GRR 19991007:  does it?  or should pixel_bytes in each
+             *   block be replaced with immediate value (e.g., 1)? */
+            /* GRR 19991017:  replaced with constants in each case */
+            {
+               if (pixel_bytes == 1)
+               {
+                  for (i = width; i; i--)
+                  {
+                     int j;
+                     for (j = 0; j < png_pass_inc[pass]; j++)
+                     {
+                        *dp-- = *sptr;
+                     }
+                     --sptr;
+                  }
+               }
+               else if (pixel_bytes == 3)
+               {
+                  for (i = width; i; i--)
+                  {
+                     png_byte v[8];
+                     int j;
+                     png_memcpy(v, sptr, 3);
+                     for (j = 0; j < png_pass_inc[pass]; j++)
+                     {
+                        png_memcpy(dp, v, 3);
+                        dp -= 3;
+                     }
+                     sptr -= 3;
+                  }
+               }
+               else if (pixel_bytes == 2)
+               {
+                  for (i = width; i; i--)
+                  {
+                     png_byte v[8];
+                     int j;
+                     png_memcpy(v, sptr, 2);
+                     for (j = 0; j < png_pass_inc[pass]; j++)
+                     {
+                        png_memcpy(dp, v, 2);
+                        dp -= 2;
+                     }
+                     sptr -= 2;
+                  }
+               }
+               else if (pixel_bytes == 4)
+               {
+                  for (i = width; i; i--)
+                  {
+                     png_byte v[8];
+                     int j;
+                     png_memcpy(v, sptr, 4);
+                     for (j = 0; j < png_pass_inc[pass]; j++)
+                     {
+#if defined(PNG_DEBUG) && defined(PNG_1_0_X)
+                        if (dp < row || dp+3 > row+png_ptr->row_buf_size)
+                        {
+                           printf("dp out of bounds: row=%d, dp=%d, rp=%d\n",
+                             row, dp, row+png_ptr->row_buf_size);
+                           printf("row_buf=%d\n",png_ptr->row_buf_size);
+                        }
+#endif
+                        png_memcpy(dp, v, 4);
+                        dp -= 4;
+                     }
+                     sptr -= 4;
+                  }
+               }
+               else if (pixel_bytes == 6)
+               {
+                  for (i = width; i; i--)
+                  {
+                     png_byte v[8];
+                     int j;
+                     png_memcpy(v, sptr, 6);
+                     for (j = 0; j < png_pass_inc[pass]; j++)
+                     {
+                        png_memcpy(dp, v, 6);
+                        dp -= 6;
+                     }
+                     sptr -= 6;
+                  }
+               }
+               else if (pixel_bytes == 8)
+               {
+                  for (i = width; i; i--)
+                  {
+                     png_byte v[8];
+                     int j;
+                     png_memcpy(v, sptr, 8);
+                     for (j = 0; j < png_pass_inc[pass]; j++)
+                     {
+                        png_memcpy(dp, v, 8);
+                        dp -= 8;
+                     }
+                     sptr -= 8;
+                  }
+               }
+               else     /* GRR:  should never be reached */
+               {
+                  for (i = width; i; i--)
+                  {
+                     png_byte v[8];
+                     int j;
+                     png_memcpy(v, sptr, pixel_bytes);
+                     for (j = 0; j < png_pass_inc[pass]; j++)
+                     {
+                        png_memcpy(dp, v, pixel_bytes);
+                        dp -= pixel_bytes;
+                     }
+                     sptr -= pixel_bytes;
+                  }
+               }
+
+            }
+            break;
+         }
+      } /* end switch (row_info->pixel_depth) */
+
+      row_info->width = final_width;
+
+      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,final_width);
+   }
+
+} /* end png_do_read_interlace() */
+
+#endif /* PNG_HAVE_MMX_READ_INTERLACE */
+#endif /* PNG_READ_INTERLACING_SUPPORTED */
+
+
+
+#if !defined(PNG_HAVE_MMX_READ_FILTER_ROW)
+/*===========================================================================*/
+/*                                                                           */
+/*                   P N G _ R E A D _ F I L T E R _ R O W                   */
+/*                                                                           */
+/*===========================================================================*/
+
+
+/* Optimized png_read_filter_row routines */
+
+void /* PRIVATE */
+png_read_filter_row(png_structp png_ptr, png_row_infop row_info, png_bytep
+   row, png_bytep prev_row, int filter)
+{
+#if defined(PNG_DEBUG)
+   char filnm[10];
+#endif
+
+
+#if defined(PNG_DEBUG)
+   png_debug(1, "in png_read_filter_row (pngrutil.c OPTIMIZED)\n");
+   switch (filter)
+   {
+      case 0:
+         png_snprintf(filnm, 10, "none");
+         break;
+
+      case 1:
+         png_snprintf(filnm, 10, "sub-%s",
+             "x86");
+         break;
+
+      case 2:
+         png_snprintf(filnm, 10, "up-%s",
+             "x86");
+         break;
+
+      case 3:
+         png_snprintf(filnm, 10, "avg-%s",
+             "x86");
+         break;
+
+      case 4:
+         png_snprintf(filnm, 10, "Paeth-%s",
+             "x86");
+         break;
+
+      default:
+         png_snprintf(filnm, 10, "unknown");
+         break;
+   }
+   png_debug2(0, "row_number=%5ld, %10s, ", png_ptr->row_number, filnm);
+   png_debug1(0, "row=0x%08lx, ", (unsigned long)row);
+   png_debug2(0, "pixdepth=%2d, bytes=%d, ", (int)row_info->pixel_depth,
+      (int)((row_info->pixel_depth + 7) >> 3));
+   png_debug1(0,"rowbytes=%8ld\n", row_info->rowbytes);
+#endif /* PNG_DEBUG */
+
+   switch (filter)
+   {
+      case PNG_FILTER_VALUE_NONE:
+         break;
+
+      case PNG_FILTER_VALUE_SUB:
+         {
+            png_uint_32 i;
+            png_uint_32 istop = row_info->rowbytes;
+            png_uint_32 bpp = (row_info->pixel_depth + 7) >> 3;
+            png_bytep rp = row + bpp;
+            png_bytep lp = row;
+
+            for (i = bpp; i < istop; i++)
+            {
+               *rp = (png_byte)(((int)(*rp) + (int)(*lp++)) & 0xff);
+               rp++;
+            }
+         }
+         break;
+
+      case PNG_FILTER_VALUE_UP:
+         {
+            png_uint_32 i;
+            png_uint_32 istop = row_info->rowbytes;
+            png_bytep rp = row;
+            png_bytep pp = prev_row;
+
+            for (i = 0; i < istop; ++i)
+            {
+               *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
+               rp++;
+            }
+         }
+         break;
+
+      case PNG_FILTER_VALUE_AVG:
+         {
+            png_uint_32 i;
+            png_bytep rp = row;
+            png_bytep pp = prev_row;
+            png_bytep lp = row;
+            png_uint_32 bpp = (row_info->pixel_depth + 7) >> 3;
+            png_uint_32 istop = row_info->rowbytes - bpp;
+
+            for (i = 0; i < bpp; i++)
+            {
+               *rp = (png_byte)(((int)(*rp) +
+                  ((int)(*pp++) >> 1)) & 0xff);
+               rp++;
+            }
+
+            for (i = 0; i < istop; i++)
+            {
+               *rp = (png_byte)(((int)(*rp) +
+                  ((int)(*pp++ + *lp++) >> 1)) & 0xff);
+               rp++;
+            }
+         }
+         break;
+
+      case PNG_FILTER_VALUE_PAETH:
+         {
+            png_uint_32 i;
+            png_bytep rp = row;
+            png_bytep pp = prev_row;
+            png_bytep lp = row;
+            png_bytep cp = prev_row;
+            png_uint_32 bpp = (row_info->pixel_depth + 7) >> 3;
+            png_uint_32 istop = row_info->rowbytes - bpp;
+
+            for (i = 0; i < bpp; i++)
+            {
+               *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
+               rp++;
+            }
+
+            for (i = 0; i < istop; i++)   /* use leftover rp,pp */
+            {
+               int a, b, c, pa, pb, pc, p;
+
+               a = *lp++;
+               b = *pp++;
+               c = *cp++;
+
+               p = b - c;
+               pc = a - c;
+
+#if defined(PNG_USE_ABS)
+               pa = abs(p);
+               pb = abs(pc);
+               pc = abs(p + pc);
+#else
+               pa = p < 0 ? -p : p;
+               pb = pc < 0 ? -pc : pc;
+               pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+#endif
+
+               /*
+                  if (pa <= pb && pa <= pc)
+                     p = a;
+                  else if (pb <= pc)
+                     p = b;
+                  else
+                     p = c;
+                */
+
+               p = (pa <= pb && pa <= pc) ? a : (pb <= pc) ? b : c;
+
+               *rp = (png_byte)(((int)(*rp) + p) & 0xff);
+               rp++;
+            }
+         }
+         break;
+
+      default:
+         png_warning(png_ptr, "Ignoring bad row-filter type");
+         *row=0;
+         break;
+   }
+}
+
+#endif /* PNG_HAVE_MMX_READ_FILTER_ROW */
+#endif /* PNG_OPTIMIZED_CODE_SUPPORTED */
+
+#if !defined(PNG_USE_PNGGCCRD) && !defined(PNG_USE_PNGVCRD)
+#if !defined(PNG_OPTIMIZED_CODE_SUPPORTED)
+/* Use the unoptimized original C code.  This might be removed from a future
+ * version of libpng if testing proves it to be worthless. */
+void /* PRIVATE */
+png_combine_row(png_structp png_ptr, png_bytep row, int mask)
+{
+   png_debug(1,"in png_combine_row NOT OPTIMIZED\n");
+   if (mask == 0xff)
+   {
+      png_memcpy(row, png_ptr->row_buf + 1,
+         PNG_ROWBYTES(png_ptr->row_info.pixel_depth, png_ptr->width));
+   }
+   else
+   {
+      switch (png_ptr->row_info.pixel_depth)
+      {
+         case 1:
+         {
+            png_bytep sp = png_ptr->row_buf + 1;
+            png_bytep dp = row;
+            int s_inc, s_start, s_end;
+            int m = 0x80;
+            int shift;
+            png_uint_32 i;
+            png_uint_32 row_width = png_ptr->width;
+
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+            if (png_ptr->transformations & PNG_PACKSWAP)
+            {
+                s_start = 0;
+                s_end = 7;
+                s_inc = 1;
+            }
+            else
+#endif
+            {
+                s_start = 7;
+                s_end = 0;
+                s_inc = -1;
+            }
+
+            shift = s_start;
+
+            for (i = 0; i < row_width; i++)
+            {
+               if (m & mask)
+               {
+                  int value;
+
+                  value = (*sp >> shift) & 0x01;
+                  *dp &= (png_byte)((0x7f7f >> (7 - shift)) & 0xff);
+                  *dp |= (png_byte)(value << shift);
+               }
+
+               if (shift == s_end)
+               {
+                  shift = s_start;
+                  sp++;
+                  dp++;
+               }
+               else
+                  shift += s_inc;
+
+               if (m == 1)
+                  m = 0x80;
+               else
+                  m >>= 1;
+            }
+            break;
+         }
+         case 2:
+         {
+            png_bytep sp = png_ptr->row_buf + 1;
+            png_bytep dp = row;
+            int s_start, s_end, s_inc;
+            int m = 0x80;
+            int shift;
+            png_uint_32 i;
+            png_uint_32 row_width = png_ptr->width;
+            int value;
+
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+            if (png_ptr->transformations & PNG_PACKSWAP)
+            {
+               s_start = 0;
+               s_end = 6;
+               s_inc = 2;
+            }
+            else
+#endif
+            {
+               s_start = 6;
+               s_end = 0;
+               s_inc = -2;
+            }
+
+            shift = s_start;
+
+            for (i = 0; i < row_width; i++)
+            {
+               if (m & mask)
+               {
+                  value = (*sp >> shift) & 0x03;
+                  *dp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
+                  *dp |= (png_byte)(value << shift);
+               }
+
+               if (shift == s_end)
+               {
+                  shift = s_start;
+                  sp++;
+                  dp++;
+               }
+               else
+                  shift += s_inc;
+               if (m == 1)
+                  m = 0x80;
+               else
+                  m >>= 1;
+            }
+            break;
+         }
+         case 4:
+         {
+            png_bytep sp = png_ptr->row_buf + 1;
+            png_bytep dp = row;
+            int s_start, s_end, s_inc;
+            int m = 0x80;
+            int shift;
+            png_uint_32 i;
+            png_uint_32 row_width = png_ptr->width;
+            int value;
+
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+            if (png_ptr->transformations & PNG_PACKSWAP)
+            {
+               s_start = 0;
+               s_end = 4;
+               s_inc = 4;
+            }
+            else
+#endif
+            {
+               s_start = 4;
+               s_end = 0;
+               s_inc = -4;
+            }
+            shift = s_start;
+
+            for (i = 0; i < row_width; i++)
+            {
+               if (m & mask)
+               {
+                  value = (*sp >> shift) & 0xf;
+                  *dp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
+                  *dp |= (png_byte)(value << shift);
+               }
+
+               if (shift == s_end)
+               {
+                  shift = s_start;
+                  sp++;
+                  dp++;
+               }
+               else
+                  shift += s_inc;
+               if (m == 1)
+                  m = 0x80;
+               else
+                  m >>= 1;
+            }
+            break;
+         }
+         default:
+         {
+            png_bytep sp = png_ptr->row_buf + 1;
+            png_bytep dp = row;
+            png_size_t pixel_bytes = (png_ptr->row_info.pixel_depth >> 3);
+            png_uint_32 i;
+            png_uint_32 row_width = png_ptr->width;
+            png_byte m = 0x80;
+
+
+            for (i = 0; i < row_width; i++)
+            {
+               if (m & mask)
+               {
+                  png_memcpy(dp, sp, pixel_bytes);
+               }
+
+               sp += pixel_bytes;
+               dp += pixel_bytes;
+
+               if (m == 1)
+                  m = 0x80;
+               else
+                  m >>= 1;
+            }
+            break;
+         }
+      }
+   }
+}
+
+#ifdef PNG_READ_INTERLACING_SUPPORTED
+/* OLD pre-1.0.9 interface:
+void png_do_read_interlace(png_row_infop row_info, png_bytep row, int pass,
+   png_uint_32 transformations)
+ */
+void /* PRIVATE */
+png_do_read_interlace(png_structp png_ptr)
+{
+   png_row_infop row_info = &(png_ptr->row_info);
+   png_bytep row = png_ptr->row_buf + 1;
+   int pass = png_ptr->pass;
+   png_uint_32 transformations = png_ptr->transformations;
+#ifdef PNG_USE_LOCAL_ARRAYS
+   /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+   /* offset to next interlace block */
+   PNG_CONST int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+#endif
+
+   png_debug(1,"in png_do_read_interlace (pngrutil.c NOT OPTIMIZED)\n");
+   if (row != NULL && row_info != NULL)
+   {
+      png_uint_32 final_width;
+
+      final_width = row_info->width * png_pass_inc[pass];
+
+      switch (row_info->pixel_depth)
+      {
+         case 1:
+         {
+            png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 3);
+            png_bytep dp = row + (png_size_t)((final_width - 1) >> 3);
+            int sshift, dshift;
+            int s_start, s_end, s_inc;
+            int jstop = png_pass_inc[pass];
+            png_byte v;
+            png_uint_32 i;
+            int j;
+
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+            if (transformations & PNG_PACKSWAP)
+            {
+                sshift = (int)((row_info->width + 7) & 0x07);
+                dshift = (int)((final_width + 7) & 0x07);
+                s_start = 7;
+                s_end = 0;
+                s_inc = -1;
+            }
+            else
+#endif
+            {
+                sshift = 7 - (int)((row_info->width + 7) & 0x07);
+                dshift = 7 - (int)((final_width + 7) & 0x07);
+                s_start = 0;
+                s_end = 7;
+                s_inc = 1;
+            }
+
+            for (i = 0; i < row_info->width; i++)
+            {
+               v = (png_byte)((*sp >> sshift) & 0x01);
+               for (j = 0; j < jstop; j++)
+               {
+                  *dp &= (png_byte)((0x7f7f >> (7 - dshift)) & 0xff);
+                  *dp |= (png_byte)(v << dshift);
+                  if (dshift == s_end)
+                  {
+                     dshift = s_start;
+                     dp--;
+                  }
+                  else
+                     dshift += s_inc;
+               }
+               if (sshift == s_end)
+               {
+                  sshift = s_start;
+                  sp--;
+               }
+               else
+                  sshift += s_inc;
+            }
+            break;
+         }
+         case 2:
+         {
+            png_bytep sp = row + (png_uint_32)((row_info->width - 1) >> 2);
+            png_bytep dp = row + (png_uint_32)((final_width - 1) >> 2);
+            int sshift, dshift;
+            int s_start, s_end, s_inc;
+            int jstop = png_pass_inc[pass];
+            png_uint_32 i;
+
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+            if (transformations & PNG_PACKSWAP)
+            {
+               sshift = (int)(((row_info->width + 3) & 0x03) << 1);
+               dshift = (int)(((final_width + 3) & 0x03) << 1);
+               s_start = 6;
+               s_end = 0;
+               s_inc = -2;
+            }
+            else
+#endif
+            {
+               sshift = (int)((3 - ((row_info->width + 3) & 0x03)) << 1);
+               dshift = (int)((3 - ((final_width + 3) & 0x03)) << 1);
+               s_start = 0;
+               s_end = 6;
+               s_inc = 2;
+            }
+
+            for (i = 0; i < row_info->width; i++)
+            {
+               png_byte v;
+               int j;
+
+               v = (png_byte)((*sp >> sshift) & 0x03);
+               for (j = 0; j < jstop; j++)
+               {
+                  *dp &= (png_byte)((0x3f3f >> (6 - dshift)) & 0xff);
+                  *dp |= (png_byte)(v << dshift);
+                  if (dshift == s_end)
+                  {
+                     dshift = s_start;
+                     dp--;
+                  }
+                  else
+                     dshift += s_inc;
+               }
+               if (sshift == s_end)
+               {
+                  sshift = s_start;
+                  sp--;
+               }
+               else
+                  sshift += s_inc;
+            }
+            break;
+         }
+         case 4:
+         {
+            png_bytep sp = row + (png_size_t)((row_info->width - 1) >> 1);
+            png_bytep dp = row + (png_size_t)((final_width - 1) >> 1);
+            int sshift, dshift;
+            int s_start, s_end, s_inc;
+            png_uint_32 i;
+            int jstop = png_pass_inc[pass];
+
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+            if (transformations & PNG_PACKSWAP)
+            {
+               sshift = (int)(((row_info->width + 1) & 0x01) << 2);
+               dshift = (int)(((final_width + 1) & 0x01) << 2);
+               s_start = 4;
+               s_end = 0;
+               s_inc = -4;
+            }
+            else
+#endif
+            {
+               sshift = (int)((1 - ((row_info->width + 1) & 0x01)) << 2);
+               dshift = (int)((1 - ((final_width + 1) & 0x01)) << 2);
+               s_start = 0;
+               s_end = 4;
+               s_inc = 4;
+            }
+
+            for (i = 0; i < row_info->width; i++)
+            {
+               png_byte v = (png_byte)((*sp >> sshift) & 0xf);
+               int j;
+
+               for (j = 0; j < jstop; j++)
+               {
+                  *dp &= (png_byte)((0xf0f >> (4 - dshift)) & 0xff);
+                  *dp |= (png_byte)(v << dshift);
+                  if (dshift == s_end)
+                  {
+                     dshift = s_start;
+                     dp--;
+                  }
+                  else
+                     dshift += s_inc;
+               }
+               if (sshift == s_end)
+               {
+                  sshift = s_start;
+                  sp--;
+               }
+               else
+                  sshift += s_inc;
+            }
+            break;
+         }
+         default:
+         {
+            png_size_t pixel_bytes = (row_info->pixel_depth >> 3);
+            png_bytep sp = row + (png_size_t)(row_info->width - 1) * pixel_bytes;
+            png_bytep dp = row + (png_size_t)(final_width - 1) * pixel_bytes;
+
+            int jstop = png_pass_inc[pass];
+            png_uint_32 i;
+
+            for (i = 0; i < row_info->width; i++)
+            {
+               png_byte v[8];
+               int j;
+
+               png_memcpy(v, sp, pixel_bytes);
+               for (j = 0; j < jstop; j++)
+               {
+                  png_memcpy(dp, v, pixel_bytes);
+                  dp -= pixel_bytes;
+               }
+               sp -= pixel_bytes;
+            }
+            break;
+         }
+      }
+      row_info->width = final_width;
+      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,final_width);
+   }
+#if !defined(PNG_READ_PACKSWAP_SUPPORTED)
+   transformations = transformations; /* silence compiler warning */
+#endif
+}
+#endif /* PNG_READ_INTERLACING_SUPPORTED */
+
+void /* PRIVATE */
+png_read_filter_row(png_structp png_ptr, png_row_infop row_info, png_bytep row,
+   png_bytep prev_row, int filter)
+{
+   png_debug(1, "in png_read_filter_row (NOT OPTIMIZED)\n");
+   png_debug2(2,"row = %lu, filter = %d\n", png_ptr->row_number, filter);
+   switch (filter)
+   {
+      case PNG_FILTER_VALUE_NONE:
+         break;
+      case PNG_FILTER_VALUE_SUB:
+      {
+         png_uint_32 i;
+         png_uint_32 istop = row_info->rowbytes;
+         png_uint_32 bpp = (row_info->pixel_depth + 7) >> 3;
+         png_bytep rp = row + bpp;
+         png_bytep lp = row;
+
+         for (i = bpp; i < istop; i++)
+         {
+            *rp = (png_byte)(((int)(*rp) + (int)(*lp++)) & 0xff);
+            rp++;
+         }
+         break;
+      }
+      case PNG_FILTER_VALUE_UP:
+      {
+         png_uint_32 i;
+         png_uint_32 istop = row_info->rowbytes;
+         png_bytep rp = row;
+         png_bytep pp = prev_row;
+
+         for (i = 0; i < istop; i++)
+         {
+            *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
+            rp++;
+         }
+         break;
+      }
+      case PNG_FILTER_VALUE_AVG:
+      {
+         png_uint_32 i;
+         png_bytep rp = row;
+         png_bytep pp = prev_row;
+         png_bytep lp = row;
+         png_uint_32 bpp = (row_info->pixel_depth + 7) >> 3;
+         png_uint_32 istop = row_info->rowbytes - bpp;
+
+         for (i = 0; i < bpp; i++)
+         {
+            *rp = (png_byte)(((int)(*rp) +
+               ((int)(*pp++) / 2 )) & 0xff);
+            rp++;
+         }
+
+         for (i = 0; i < istop; i++)
+         {
+            *rp = (png_byte)(((int)(*rp) +
+               (int)(*pp++ + *lp++) / 2 ) & 0xff);
+            rp++;
+         }
+         break;
+      }
+      case PNG_FILTER_VALUE_PAETH:
+      {
+         png_uint_32 i;
+         png_bytep rp = row;
+         png_bytep pp = prev_row;
+         png_bytep lp = row;
+         png_bytep cp = prev_row;
+         png_uint_32 bpp = (row_info->pixel_depth + 7) >> 3;
+         png_uint_32 istop=row_info->rowbytes - bpp;
+
+         for (i = 0; i < bpp; i++)
+         {
+            *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
+            rp++;
+         }
+
+         for (i = 0; i < istop; i++)   /* use leftover rp,pp */
+         {
+            int a, b, c, pa, pb, pc, p;
+
+            a = *lp++;
+            b = *pp++;
+            c = *cp++;
+
+            p = b - c;
+            pc = a - c;
+
+#ifdef PNG_USE_ABS
+            pa = abs(p);
+            pb = abs(pc);
+            pc = abs(p + pc);
+#else
+            pa = p < 0 ? -p : p;
+            pb = pc < 0 ? -pc : pc;
+            pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+#endif
+
+            /*
+               if (pa <= pb && pa <= pc)
+                  p = a;
+               else if (pb <= pc)
+                  p = b;
+               else
+                  p = c;
+             */
+
+            p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
+
+            *rp = (png_byte)(((int)(*rp) + p) & 0xff);
+            rp++;
+         }
+         break;
+      }
+      default:
+         png_warning(png_ptr, "Ignoring bad adaptive filter type");
+         *row=0;
+         break;
+   }
+}
+#endif /* !PNG_OPTIMIZED_CODE_SUPPORTED */
+#endif /* !PNG_USE_PNGGCCRD && !PNG_USE_PNGVCRD */
+
+void /* PRIVATE */
+png_read_finish_row(png_structp png_ptr)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+   /* start of interlace block */
+   PNG_CONST int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+
+   /* offset to next interlace block */
+   PNG_CONST int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+
+   /* start of interlace block in the y direction */
+   PNG_CONST int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
+
+   /* offset to next interlace block in the y direction */
+   PNG_CONST int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+#endif
+
+   png_debug(1, "in png_read_finish_row\n");
+   png_ptr->row_number++;
+   if (png_ptr->row_number < png_ptr->num_rows)
+      return;
+
+   if (png_ptr->interlaced)
+   {
+      png_ptr->row_number = 0;
+      png_memset_check(png_ptr, png_ptr->prev_row, 0,
+         png_ptr->rowbytes + 1);
+      do
+      {
+         png_ptr->pass++;
+         if (png_ptr->pass >= 7)
+            break;
+         png_ptr->iwidth = (png_ptr->width +
+            png_pass_inc[png_ptr->pass] - 1 -
+            png_pass_start[png_ptr->pass]) /
+            png_pass_inc[png_ptr->pass];
+
+         png_ptr->irowbytes = PNG_ROWBYTES(png_ptr->pixel_depth,
+            png_ptr->iwidth) + 1;
+
+         if (!(png_ptr->transformations & PNG_INTERLACE))
+         {
+            png_ptr->num_rows = (png_ptr->height +
+               png_pass_yinc[png_ptr->pass] - 1 -
+               png_pass_ystart[png_ptr->pass]) /
+               png_pass_yinc[png_ptr->pass];
+            if (!(png_ptr->num_rows))
+               continue;
+         }
+         else  /* if (png_ptr->transformations & PNG_INTERLACE) */
+            break;
+      } while (png_ptr->iwidth == 0);
+
+      if (png_ptr->pass < 7)
+         return;
+   }
+
+   if (!(png_ptr->flags & PNG_FLAG_ZLIB_FINISHED))
+   {
+#ifdef PNG_USE_LOCAL_ARRAYS
+      PNG_CONST PNG_IDAT;
+#endif
+      char extra;
+      int ret;
+
+      png_ptr->zstream.next_out = (Byte *)&extra;
+      png_ptr->zstream.avail_out = (uInt)1;
+      for(;;)
+      {
+         if (!(png_ptr->zstream.avail_in))
+         {
+            while (!png_ptr->idat_size)
+            {
+               png_byte chunk_length[4];
+
+               png_crc_finish(png_ptr, 0);
+
+               png_read_data(png_ptr, chunk_length, 4);
+               png_ptr->idat_size = png_get_uint_31(png_ptr, chunk_length);
+               png_reset_crc(png_ptr);
+               png_crc_read(png_ptr, png_ptr->chunk_name, 4);
+               if (png_memcmp(png_ptr->chunk_name, (png_bytep)png_IDAT, 4))
+                  png_error(png_ptr, "Not enough image data");
+
+            }
+            png_ptr->zstream.avail_in = (uInt)png_ptr->zbuf_size;
+            png_ptr->zstream.next_in = png_ptr->zbuf;
+            if (png_ptr->zbuf_size > png_ptr->idat_size)
+               png_ptr->zstream.avail_in = (uInt)png_ptr->idat_size;
+            png_crc_read(png_ptr, png_ptr->zbuf, png_ptr->zstream.avail_in);
+            png_ptr->idat_size -= png_ptr->zstream.avail_in;
+         }
+         ret = inflate(&png_ptr->zstream, Z_PARTIAL_FLUSH);
+         if (ret == Z_STREAM_END)
+         {
+            if (!(png_ptr->zstream.avail_out) || png_ptr->zstream.avail_in ||
+               png_ptr->idat_size)
+               png_warning(png_ptr, "Extra compressed data");
+            png_ptr->mode |= PNG_AFTER_IDAT;
+            png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
+            break;
+         }
+         if (ret != Z_OK)
+            png_error(png_ptr, png_ptr->zstream.msg ? png_ptr->zstream.msg :
+                      "Decompression Error");
+
+         if (!(png_ptr->zstream.avail_out))
+         {
+            png_warning(png_ptr, "Extra compressed data.");
+            png_ptr->mode |= PNG_AFTER_IDAT;
+            png_ptr->flags |= PNG_FLAG_ZLIB_FINISHED;
+            break;
+         }
+
+      }
+      png_ptr->zstream.avail_out = 0;
+   }
+
+   if (png_ptr->idat_size || png_ptr->zstream.avail_in)
+      png_warning(png_ptr, "Extra compression data");
+
+   inflateReset(&png_ptr->zstream);
+
+   png_ptr->mode |= PNG_AFTER_IDAT;
+}
+
+void /* PRIVATE */
+png_read_start_row(png_structp png_ptr)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+   /* start of interlace block */
+   PNG_CONST int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+
+   /* offset to next interlace block */
+   PNG_CONST int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+
+   /* start of interlace block in the y direction */
+   PNG_CONST int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
+
+   /* offset to next interlace block in the y direction */
+   PNG_CONST int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+#endif
+
+   int max_pixel_depth;
+   png_uint_32 row_bytes;
+
+   png_debug(1, "in png_read_start_row\n");
+   png_ptr->zstream.avail_in = 0;
+   png_init_read_transformations(png_ptr);
+   if (png_ptr->interlaced)
+   {
+      if (!(png_ptr->transformations & PNG_INTERLACE))
+         png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
+            png_pass_ystart[0]) / png_pass_yinc[0];
+      else
+         png_ptr->num_rows = png_ptr->height;
+
+      png_ptr->iwidth = (png_ptr->width +
+         png_pass_inc[png_ptr->pass] - 1 -
+         png_pass_start[png_ptr->pass]) /
+         png_pass_inc[png_ptr->pass];
+
+         row_bytes = PNG_ROWBYTES(png_ptr->pixel_depth,png_ptr->iwidth) + 1;
+
+         png_ptr->irowbytes = (png_size_t)row_bytes;
+         if((png_uint_32)png_ptr->irowbytes != row_bytes)
+            png_error(png_ptr, "Rowbytes overflow in png_read_start_row");
+   }
+   else
+   {
+      png_ptr->num_rows = png_ptr->height;
+      png_ptr->iwidth = png_ptr->width;
+      png_ptr->irowbytes = png_ptr->rowbytes + 1;
+   }
+   max_pixel_depth = png_ptr->pixel_depth;
+
+#if defined(PNG_READ_PACK_SUPPORTED)
+   if ((png_ptr->transformations & PNG_PACK) && png_ptr->bit_depth < 8)
+      max_pixel_depth = 8;
+#endif
+
+#if defined(PNG_READ_EXPAND_SUPPORTED)
+   if (png_ptr->transformations & PNG_EXPAND)
+   {
+      if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      {
+         if (png_ptr->num_trans)
+            max_pixel_depth = 32;
+         else
+            max_pixel_depth = 24;
+      }
+      else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
+      {
+         if (max_pixel_depth < 8)
+            max_pixel_depth = 8;
+         if (png_ptr->num_trans)
+            max_pixel_depth *= 2;
+      }
+      else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
+      {
+         if (png_ptr->num_trans)
+         {
+            max_pixel_depth *= 4;
+            max_pixel_depth /= 3;
+         }
+      }
+   }
+#endif
+
+#if defined(PNG_READ_FILLER_SUPPORTED)
+   if (png_ptr->transformations & (PNG_FILLER))
+   {
+      if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+         max_pixel_depth = 32;
+      else if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY)
+      {
+         if (max_pixel_depth <= 8)
+            max_pixel_depth = 16;
+         else
+            max_pixel_depth = 32;
+      }
+      else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
+      {
+         if (max_pixel_depth <= 32)
+            max_pixel_depth = 32;
+         else
+            max_pixel_depth = 64;
+      }
+   }
+#endif
+
+#if defined(PNG_READ_GRAY_TO_RGB_SUPPORTED)
+   if (png_ptr->transformations & PNG_GRAY_TO_RGB)
+   {
+      if (
+#if defined(PNG_READ_EXPAND_SUPPORTED)
+        (png_ptr->num_trans && (png_ptr->transformations & PNG_EXPAND)) ||
+#endif
+#if defined(PNG_READ_FILLER_SUPPORTED)
+        (png_ptr->transformations & (PNG_FILLER)) ||
+#endif
+        png_ptr->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      {
+         if (max_pixel_depth <= 16)
+            max_pixel_depth = 32;
+         else
+            max_pixel_depth = 64;
+      }
+      else
+      {
+         if (max_pixel_depth <= 8)
+           {
+             if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+               max_pixel_depth = 32;
+             else
+               max_pixel_depth = 24;
+           }
+         else if (png_ptr->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+            max_pixel_depth = 64;
+         else
+            max_pixel_depth = 48;
+      }
+   }
+#endif
+
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) && \
+defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
+   if(png_ptr->transformations & PNG_USER_TRANSFORM)
+     {
+       int user_pixel_depth=png_ptr->user_transform_depth*
+         png_ptr->user_transform_channels;
+       if(user_pixel_depth > max_pixel_depth)
+         max_pixel_depth=user_pixel_depth;
+     }
+#endif
+
+   /* align the width on the next larger 8 pixels.  Mainly used
+      for interlacing */
+   row_bytes = ((png_ptr->width + 7) & ~((png_uint_32)7));
+   /* calculate the maximum bytes needed, adding a byte and a pixel
+      for safety's sake */
+   row_bytes = PNG_ROWBYTES(max_pixel_depth,row_bytes) +
+      1 + ((max_pixel_depth + 7) >> 3);
+#ifdef PNG_MAX_MALLOC_64K
+   if (row_bytes > (png_uint_32)65536L)
+      png_error(png_ptr, "This image requires a row greater than 64KB");
+#endif
+   png_ptr->big_row_buf = (png_bytep)png_malloc(png_ptr, row_bytes+64);
+   png_ptr->row_buf = png_ptr->big_row_buf+32;
+#if defined(PNG_DEBUG) && defined(PNG_USE_PNGGCCRD) && defined(PNG_1_0_X)
+   png_ptr->row_buf_size = row_bytes;
+#endif
+
+#ifdef PNG_MAX_MALLOC_64K
+   if ((png_uint_32)png_ptr->rowbytes + 1 > (png_uint_32)65536L)
+      png_error(png_ptr, "This image requires a row greater than 64KB");
+#endif
+   if ((png_uint_32)png_ptr->rowbytes > (png_uint_32)(PNG_SIZE_MAX - 1))
+      png_error(png_ptr, "Row has too many bytes to allocate in memory.");
+   png_ptr->prev_row = (png_bytep)png_malloc(png_ptr, (png_uint_32)(
+      png_ptr->rowbytes + 1));
+
+   png_memset_check(png_ptr, png_ptr->prev_row, 0, png_ptr->rowbytes + 1);
+
+   png_debug1(3, "width = %lu,\n", png_ptr->width);
+   png_debug1(3, "height = %lu,\n", png_ptr->height);
+   png_debug1(3, "iwidth = %lu,\n", png_ptr->iwidth);
+   png_debug1(3, "num_rows = %lu\n", png_ptr->num_rows);
+   png_debug1(3, "rowbytes = %lu,\n", png_ptr->rowbytes);
+   png_debug1(3, "irowbytes = %lu,\n", png_ptr->irowbytes);
+
+   png_ptr->flags |= PNG_FLAG_ROW_INIT;
+}
+#endif /* PNG_READ_SUPPORTED */
diff --git a/distrib/libpng-1.2.19/pngset.c b/distrib/libpng-1.2.19/pngset.c
new file mode 100644
index 0000000..8d1cbfc
--- /dev/null
+++ b/distrib/libpng-1.2.19/pngset.c
@@ -0,0 +1,1284 @@
+
+/* pngset.c - storage of image information into info struct
+ *
+ * Last changed in libpng 1.2.17 May 15, 2007
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1998-2007 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * The functions here are used during reads to store data from the file
+ * into the info struct, and during writes to store application data
+ * into the info struct for writing into the file.  This abstracts the
+ * info struct and allows us to change the structure in the future.
+ */
+
+#define PNG_INTERNAL
+#include "png.h"
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+
+#if defined(PNG_bKGD_SUPPORTED)
+void PNGAPI
+png_set_bKGD(png_structp png_ptr, png_infop info_ptr, png_color_16p background)
+{
+   png_debug1(1, "in %s storage function\n", "bKGD");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   png_memcpy(&(info_ptr->background), background, png_sizeof(png_color_16));
+   info_ptr->valid |= PNG_INFO_bKGD;
+}
+#endif
+
+#if defined(PNG_cHRM_SUPPORTED)
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
+png_set_cHRM(png_structp png_ptr, png_infop info_ptr,
+   double white_x, double white_y, double red_x, double red_y,
+   double green_x, double green_y, double blue_x, double blue_y)
+{
+   png_debug1(1, "in %s storage function\n", "cHRM");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   if (white_x < 0.0 || white_y < 0.0 ||
+         red_x < 0.0 ||   red_y < 0.0 ||
+       green_x < 0.0 || green_y < 0.0 ||
+        blue_x < 0.0 ||  blue_y < 0.0)
+   {
+      png_warning(png_ptr,
+        "Ignoring attempt to set negative chromaticity value");
+      return;
+   }
+   if (white_x > 21474.83 || white_y > 21474.83 ||
+         red_x > 21474.83 ||   red_y > 21474.83 ||
+       green_x > 21474.83 || green_y > 21474.83 ||
+        blue_x > 21474.83 ||  blue_y > 21474.83)
+   {
+      png_warning(png_ptr,
+        "Ignoring attempt to set chromaticity value exceeding 21474.83");
+      return;
+   }
+
+   info_ptr->x_white = (float)white_x;
+   info_ptr->y_white = (float)white_y;
+   info_ptr->x_red   = (float)red_x;
+   info_ptr->y_red   = (float)red_y;
+   info_ptr->x_green = (float)green_x;
+   info_ptr->y_green = (float)green_y;
+   info_ptr->x_blue  = (float)blue_x;
+   info_ptr->y_blue  = (float)blue_y;
+#ifdef PNG_FIXED_POINT_SUPPORTED
+   info_ptr->int_x_white = (png_fixed_point)(white_x*100000.+0.5);
+   info_ptr->int_y_white = (png_fixed_point)(white_y*100000.+0.5);
+   info_ptr->int_x_red   = (png_fixed_point)(  red_x*100000.+0.5);
+   info_ptr->int_y_red   = (png_fixed_point)(  red_y*100000.+0.5);
+   info_ptr->int_x_green = (png_fixed_point)(green_x*100000.+0.5);
+   info_ptr->int_y_green = (png_fixed_point)(green_y*100000.+0.5);
+   info_ptr->int_x_blue  = (png_fixed_point)( blue_x*100000.+0.5);
+   info_ptr->int_y_blue  = (png_fixed_point)( blue_y*100000.+0.5);
+#endif
+   info_ptr->valid |= PNG_INFO_cHRM;
+}
+#endif
+#ifdef PNG_FIXED_POINT_SUPPORTED
+void PNGAPI
+png_set_cHRM_fixed(png_structp png_ptr, png_infop info_ptr,
+   png_fixed_point white_x, png_fixed_point white_y, png_fixed_point red_x,
+   png_fixed_point red_y, png_fixed_point green_x, png_fixed_point green_y,
+   png_fixed_point blue_x, png_fixed_point blue_y)
+{
+   png_debug1(1, "in %s storage function\n", "cHRM");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   if (white_x < 0 || white_y < 0 ||
+         red_x < 0 ||   red_y < 0 ||
+       green_x < 0 || green_y < 0 ||
+        blue_x < 0 ||  blue_y < 0)
+   {
+      png_warning(png_ptr,
+        "Ignoring attempt to set negative chromaticity value");
+      return;
+   }
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+   if (white_x > (double) PNG_UINT_31_MAX ||
+       white_y > (double) PNG_UINT_31_MAX ||
+         red_x > (double) PNG_UINT_31_MAX ||
+         red_y > (double) PNG_UINT_31_MAX ||
+       green_x > (double) PNG_UINT_31_MAX ||
+       green_y > (double) PNG_UINT_31_MAX ||
+        blue_x > (double) PNG_UINT_31_MAX ||
+        blue_y > (double) PNG_UINT_31_MAX)
+#else
+   if (white_x > (png_fixed_point) PNG_UINT_31_MAX/100000L ||
+       white_y > (png_fixed_point) PNG_UINT_31_MAX/100000L ||
+         red_x > (png_fixed_point) PNG_UINT_31_MAX/100000L ||
+         red_y > (png_fixed_point) PNG_UINT_31_MAX/100000L ||
+       green_x > (png_fixed_point) PNG_UINT_31_MAX/100000L ||
+       green_y > (png_fixed_point) PNG_UINT_31_MAX/100000L ||
+        blue_x > (png_fixed_point) PNG_UINT_31_MAX/100000L ||
+        blue_y > (png_fixed_point) PNG_UINT_31_MAX/100000L)
+#endif
+   {
+      png_warning(png_ptr,
+        "Ignoring attempt to set chromaticity value exceeding 21474.83");
+      return;
+   }
+   info_ptr->int_x_white = white_x;
+   info_ptr->int_y_white = white_y;
+   info_ptr->int_x_red   = red_x;
+   info_ptr->int_y_red   = red_y;
+   info_ptr->int_x_green = green_x;
+   info_ptr->int_y_green = green_y;
+   info_ptr->int_x_blue  = blue_x;
+   info_ptr->int_y_blue  = blue_y;
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+   info_ptr->x_white = (float)(white_x/100000.);
+   info_ptr->y_white = (float)(white_y/100000.);
+   info_ptr->x_red   = (float)(  red_x/100000.);
+   info_ptr->y_red   = (float)(  red_y/100000.);
+   info_ptr->x_green = (float)(green_x/100000.);
+   info_ptr->y_green = (float)(green_y/100000.);
+   info_ptr->x_blue  = (float)( blue_x/100000.);
+   info_ptr->y_blue  = (float)( blue_y/100000.);
+#endif
+   info_ptr->valid |= PNG_INFO_cHRM;
+}
+#endif
+#endif
+
+#if defined(PNG_gAMA_SUPPORTED)
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
+png_set_gAMA(png_structp png_ptr, png_infop info_ptr, double file_gamma)
+{
+   double gamma;
+   png_debug1(1, "in %s storage function\n", "gAMA");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   /* Check for overflow */
+   if (file_gamma > 21474.83)
+   {
+      png_warning(png_ptr, "Limiting gamma to 21474.83");
+      gamma=21474.83;
+   }
+   else
+      gamma=file_gamma;
+   info_ptr->gamma = (float)gamma;
+#ifdef PNG_FIXED_POINT_SUPPORTED
+   info_ptr->int_gamma = (int)(gamma*100000.+.5);
+#endif
+   info_ptr->valid |= PNG_INFO_gAMA;
+   if(gamma == 0.0)
+      png_warning(png_ptr, "Setting gamma=0");
+}
+#endif
+void PNGAPI
+png_set_gAMA_fixed(png_structp png_ptr, png_infop info_ptr, png_fixed_point
+   int_gamma)
+{
+   png_fixed_point gamma;
+
+   png_debug1(1, "in %s storage function\n", "gAMA");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   if (int_gamma > (png_fixed_point) PNG_UINT_31_MAX)
+   {
+     png_warning(png_ptr, "Limiting gamma to 21474.83");
+     gamma=PNG_UINT_31_MAX;
+   }
+   else
+   {
+     if (int_gamma < 0)
+     {
+       png_warning(png_ptr, "Setting negative gamma to zero");
+       gamma=0;
+     }
+     else
+       gamma=int_gamma;
+   }
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+   info_ptr->gamma = (float)(gamma/100000.);
+#endif
+#ifdef PNG_FIXED_POINT_SUPPORTED
+   info_ptr->int_gamma = gamma;
+#endif
+   info_ptr->valid |= PNG_INFO_gAMA;
+   if(gamma == 0)
+      png_warning(png_ptr, "Setting gamma=0");
+}
+#endif
+
+#if defined(PNG_hIST_SUPPORTED)
+void PNGAPI
+png_set_hIST(png_structp png_ptr, png_infop info_ptr, png_uint_16p hist)
+{
+   int i;
+
+   png_debug1(1, "in %s storage function\n", "hIST");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+   if (info_ptr->num_palette <= 0 || info_ptr->num_palette
+       > PNG_MAX_PALETTE_LENGTH)
+   {
+       png_warning(png_ptr,
+          "Invalid palette size, hIST allocation skipped.");
+       return;
+   }
+
+#ifdef PNG_FREE_ME_SUPPORTED
+   png_free_data(png_ptr, info_ptr, PNG_FREE_HIST, 0);
+#endif
+   /* Changed from info->num_palette to PNG_MAX_PALETTE_LENGTH in version
+      1.2.1 */
+   png_ptr->hist = (png_uint_16p)png_malloc_warn(png_ptr,
+      (png_uint_32)(PNG_MAX_PALETTE_LENGTH * png_sizeof (png_uint_16)));
+   if (png_ptr->hist == NULL)
+     {
+       png_warning(png_ptr, "Insufficient memory for hIST chunk data.");
+       return;
+     }
+
+   for (i = 0; i < info_ptr->num_palette; i++)
+       png_ptr->hist[i] = hist[i];
+   info_ptr->hist = png_ptr->hist;
+   info_ptr->valid |= PNG_INFO_hIST;
+
+#ifdef PNG_FREE_ME_SUPPORTED
+   info_ptr->free_me |= PNG_FREE_HIST;
+#else
+   png_ptr->flags |= PNG_FLAG_FREE_HIST;
+#endif
+}
+#endif
+
+void PNGAPI
+png_set_IHDR(png_structp png_ptr, png_infop info_ptr,
+   png_uint_32 width, png_uint_32 height, int bit_depth,
+   int color_type, int interlace_type, int compression_type,
+   int filter_type)
+{
+   png_debug1(1, "in %s storage function\n", "IHDR");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   /* check for width and height valid values */
+   if (width == 0 || height == 0)
+      png_error(png_ptr, "Image width or height is zero in IHDR");
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+   if (width > png_ptr->user_width_max || height > png_ptr->user_height_max)
+      png_error(png_ptr, "image size exceeds user limits in IHDR");
+#else
+   if (width > PNG_USER_WIDTH_MAX || height > PNG_USER_HEIGHT_MAX)
+      png_error(png_ptr, "image size exceeds user limits in IHDR");
+#endif
+   if (width > PNG_UINT_31_MAX || height > PNG_UINT_31_MAX)
+      png_error(png_ptr, "Invalid image size in IHDR");
+   if ( width > (PNG_UINT_32_MAX
+                 >> 3)      /* 8-byte RGBA pixels */
+                 - 64       /* bigrowbuf hack */
+                 - 1        /* filter byte */
+                 - 7*8      /* rounding of width to multiple of 8 pixels */
+                 - 8)       /* extra max_pixel_depth pad */
+      png_warning(png_ptr, "Width is too large for libpng to process pixels");
+
+   /* check other values */
+   if (bit_depth != 1 && bit_depth != 2 && bit_depth != 4 &&
+      bit_depth != 8 && bit_depth != 16)
+      png_error(png_ptr, "Invalid bit depth in IHDR");
+
+   if (color_type < 0 || color_type == 1 ||
+      color_type == 5 || color_type > 6)
+      png_error(png_ptr, "Invalid color type in IHDR");
+
+   if (((color_type == PNG_COLOR_TYPE_PALETTE) && bit_depth > 8) ||
+       ((color_type == PNG_COLOR_TYPE_RGB ||
+         color_type == PNG_COLOR_TYPE_GRAY_ALPHA ||
+         color_type == PNG_COLOR_TYPE_RGB_ALPHA) && bit_depth < 8))
+      png_error(png_ptr, "Invalid color type/bit depth combination in IHDR");
+
+   if (interlace_type >= PNG_INTERLACE_LAST)
+      png_error(png_ptr, "Unknown interlace method in IHDR");
+
+   if (compression_type != PNG_COMPRESSION_TYPE_BASE)
+      png_error(png_ptr, "Unknown compression method in IHDR");
+
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
+   /* Accept filter_method 64 (intrapixel differencing) only if
+    * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
+    * 2. Libpng did not read a PNG signature (this filter_method is only
+    *    used in PNG datastreams that are embedded in MNG datastreams) and
+    * 3. The application called png_permit_mng_features with a mask that
+    *    included PNG_FLAG_MNG_FILTER_64 and
+    * 4. The filter_method is 64 and
+    * 5. The color_type is RGB or RGBA
+    */
+   if((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE)&&png_ptr->mng_features_permitted)
+      png_warning(png_ptr,"MNG features are not allowed in a PNG datastream");
+   if(filter_type != PNG_FILTER_TYPE_BASE)
+   {
+     if(!((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
+        (filter_type == PNG_INTRAPIXEL_DIFFERENCING) &&
+        ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) == 0) &&
+        (color_type == PNG_COLOR_TYPE_RGB ||
+         color_type == PNG_COLOR_TYPE_RGB_ALPHA)))
+        png_error(png_ptr, "Unknown filter method in IHDR");
+     if(png_ptr->mode&PNG_HAVE_PNG_SIGNATURE)
+        png_warning(png_ptr, "Invalid filter method in IHDR");
+   }
+#else
+   if(filter_type != PNG_FILTER_TYPE_BASE)
+      png_error(png_ptr, "Unknown filter method in IHDR");
+#endif
+
+   info_ptr->width = width;
+   info_ptr->height = height;
+   info_ptr->bit_depth = (png_byte)bit_depth;
+   info_ptr->color_type =(png_byte) color_type;
+   info_ptr->compression_type = (png_byte)compression_type;
+   info_ptr->filter_type = (png_byte)filter_type;
+   info_ptr->interlace_type = (png_byte)interlace_type;
+   if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      info_ptr->channels = 1;
+   else if (info_ptr->color_type & PNG_COLOR_MASK_COLOR)
+      info_ptr->channels = 3;
+   else
+      info_ptr->channels = 1;
+   if (info_ptr->color_type & PNG_COLOR_MASK_ALPHA)
+      info_ptr->channels++;
+   info_ptr->pixel_depth = (png_byte)(info_ptr->channels * info_ptr->bit_depth);
+
+   /* check for potential overflow */
+   if (width > (PNG_UINT_32_MAX
+                 >> 3)      /* 8-byte RGBA pixels */
+                 - 64       /* bigrowbuf hack */
+                 - 1        /* filter byte */
+                 - 7*8      /* rounding of width to multiple of 8 pixels */
+                 - 8)       /* extra max_pixel_depth pad */
+      info_ptr->rowbytes = (png_size_t)0;
+   else
+      info_ptr->rowbytes = PNG_ROWBYTES(info_ptr->pixel_depth,width);
+}
+
+#if defined(PNG_oFFs_SUPPORTED)
+void PNGAPI
+png_set_oFFs(png_structp png_ptr, png_infop info_ptr,
+   png_int_32 offset_x, png_int_32 offset_y, int unit_type)
+{
+   png_debug1(1, "in %s storage function\n", "oFFs");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   info_ptr->x_offset = offset_x;
+   info_ptr->y_offset = offset_y;
+   info_ptr->offset_unit_type = (png_byte)unit_type;
+   info_ptr->valid |= PNG_INFO_oFFs;
+}
+#endif
+
+#if defined(PNG_pCAL_SUPPORTED)
+void PNGAPI
+png_set_pCAL(png_structp png_ptr, png_infop info_ptr,
+   png_charp purpose, png_int_32 X0, png_int_32 X1, int type, int nparams,
+   png_charp units, png_charpp params)
+{
+   png_uint_32 length;
+   int i;
+
+   png_debug1(1, "in %s storage function\n", "pCAL");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   length = png_strlen(purpose) + 1;
+   png_debug1(3, "allocating purpose for info (%lu bytes)\n", length);
+   info_ptr->pcal_purpose = (png_charp)png_malloc_warn(png_ptr, length);
+   if (info_ptr->pcal_purpose == NULL)
+     {
+       png_warning(png_ptr, "Insufficient memory for pCAL purpose.");
+       return;
+     }
+   png_memcpy(info_ptr->pcal_purpose, purpose, (png_size_t)length);
+
+   png_debug(3, "storing X0, X1, type, and nparams in info\n");
+   info_ptr->pcal_X0 = X0;
+   info_ptr->pcal_X1 = X1;
+   info_ptr->pcal_type = (png_byte)type;
+   info_ptr->pcal_nparams = (png_byte)nparams;
+
+   length = png_strlen(units) + 1;
+   png_debug1(3, "allocating units for info (%lu bytes)\n", length);
+   info_ptr->pcal_units = (png_charp)png_malloc_warn(png_ptr, length);
+   if (info_ptr->pcal_units == NULL)
+     {
+       png_warning(png_ptr, "Insufficient memory for pCAL units.");
+       return;
+     }
+   png_memcpy(info_ptr->pcal_units, units, (png_size_t)length);
+
+   info_ptr->pcal_params = (png_charpp)png_malloc_warn(png_ptr,
+      (png_uint_32)((nparams + 1) * png_sizeof(png_charp)));
+   if (info_ptr->pcal_params == NULL)
+     {
+       png_warning(png_ptr, "Insufficient memory for pCAL params.");
+       return;
+     }
+
+   info_ptr->pcal_params[nparams] = NULL;
+
+   for (i = 0; i < nparams; i++)
+   {
+      length = png_strlen(params[i]) + 1;
+      png_debug2(3, "allocating parameter %d for info (%lu bytes)\n", i, length);
+      info_ptr->pcal_params[i] = (png_charp)png_malloc_warn(png_ptr, length);
+      if (info_ptr->pcal_params[i] == NULL)
+        {
+          png_warning(png_ptr, "Insufficient memory for pCAL parameter.");
+          return;
+        }
+      png_memcpy(info_ptr->pcal_params[i], params[i], (png_size_t)length);
+   }
+
+   info_ptr->valid |= PNG_INFO_pCAL;
+#ifdef PNG_FREE_ME_SUPPORTED
+   info_ptr->free_me |= PNG_FREE_PCAL;
+#endif
+}
+#endif
+
+#if defined(PNG_READ_sCAL_SUPPORTED) || defined(PNG_WRITE_sCAL_SUPPORTED)
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+void PNGAPI
+png_set_sCAL(png_structp png_ptr, png_infop info_ptr,
+             int unit, double width, double height)
+{
+   png_debug1(1, "in %s storage function\n", "sCAL");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   info_ptr->scal_unit = (png_byte)unit;
+   info_ptr->scal_pixel_width = width;
+   info_ptr->scal_pixel_height = height;
+
+   info_ptr->valid |= PNG_INFO_sCAL;
+}
+#else
+#ifdef PNG_FIXED_POINT_SUPPORTED
+void PNGAPI
+png_set_sCAL_s(png_structp png_ptr, png_infop info_ptr,
+             int unit, png_charp swidth, png_charp sheight)
+{
+   png_uint_32 length;
+
+   png_debug1(1, "in %s storage function\n", "sCAL");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   info_ptr->scal_unit = (png_byte)unit;
+
+   length = png_strlen(swidth) + 1;
+   png_debug1(3, "allocating unit for info (%d bytes)\n", length);
+   info_ptr->scal_s_width = (png_charp)png_malloc_warn(png_ptr, length);
+   if (info_ptr->scal_s_width == NULL)
+   {
+      png_warning(png_ptr,
+       "Memory allocation failed while processing sCAL.");
+   }
+   png_memcpy(info_ptr->scal_s_width, swidth, (png_size_t)length);
+
+   length = png_strlen(sheight) + 1;
+   png_debug1(3, "allocating unit for info (%d bytes)\n", length);
+   info_ptr->scal_s_height = (png_charp)png_malloc_warn(png_ptr, length);
+   if (info_ptr->scal_s_height == NULL)
+   {
+      png_free (png_ptr, info_ptr->scal_s_width);
+      png_warning(png_ptr,
+       "Memory allocation failed while processing sCAL.");
+   }
+   png_memcpy(info_ptr->scal_s_height, sheight, (png_size_t)length);
+
+   info_ptr->valid |= PNG_INFO_sCAL;
+#ifdef PNG_FREE_ME_SUPPORTED
+   info_ptr->free_me |= PNG_FREE_SCAL;
+#endif
+}
+#endif
+#endif
+#endif
+
+#if defined(PNG_pHYs_SUPPORTED)
+void PNGAPI
+png_set_pHYs(png_structp png_ptr, png_infop info_ptr,
+   png_uint_32 res_x, png_uint_32 res_y, int unit_type)
+{
+   png_debug1(1, "in %s storage function\n", "pHYs");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   info_ptr->x_pixels_per_unit = res_x;
+   info_ptr->y_pixels_per_unit = res_y;
+   info_ptr->phys_unit_type = (png_byte)unit_type;
+   info_ptr->valid |= PNG_INFO_pHYs;
+}
+#endif
+
+void PNGAPI
+png_set_PLTE(png_structp png_ptr, png_infop info_ptr,
+   png_colorp palette, int num_palette)
+{
+
+   png_debug1(1, "in %s storage function\n", "PLTE");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   if (num_palette < 0 || num_palette > PNG_MAX_PALETTE_LENGTH)
+     {
+       if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+         png_error(png_ptr, "Invalid palette length");
+       else
+       {
+         png_warning(png_ptr, "Invalid palette length");
+         return;
+       }
+     }
+
+   /*
+    * It may not actually be necessary to set png_ptr->palette here;
+    * we do it for backward compatibility with the way the png_handle_tRNS
+    * function used to do the allocation.
+    */
+#ifdef PNG_FREE_ME_SUPPORTED
+   png_free_data(png_ptr, info_ptr, PNG_FREE_PLTE, 0);
+#endif
+
+   /* Changed in libpng-1.2.1 to allocate PNG_MAX_PALETTE_LENGTH instead
+      of num_palette entries,
+      in case of an invalid PNG file that has too-large sample values. */
+   png_ptr->palette = (png_colorp)png_malloc(png_ptr,
+      PNG_MAX_PALETTE_LENGTH * png_sizeof(png_color));
+   png_memset(png_ptr->palette, 0, PNG_MAX_PALETTE_LENGTH *
+      png_sizeof(png_color));
+   png_memcpy(png_ptr->palette, palette, num_palette * png_sizeof (png_color));
+   info_ptr->palette = png_ptr->palette;
+   info_ptr->num_palette = png_ptr->num_palette = (png_uint_16)num_palette;
+
+#ifdef PNG_FREE_ME_SUPPORTED
+   info_ptr->free_me |= PNG_FREE_PLTE;
+#else
+   png_ptr->flags |= PNG_FLAG_FREE_PLTE;
+#endif
+
+   info_ptr->valid |= PNG_INFO_PLTE;
+}
+
+#if defined(PNG_sBIT_SUPPORTED)
+void PNGAPI
+png_set_sBIT(png_structp png_ptr, png_infop info_ptr,
+   png_color_8p sig_bit)
+{
+   png_debug1(1, "in %s storage function\n", "sBIT");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   png_memcpy(&(info_ptr->sig_bit), sig_bit, png_sizeof (png_color_8));
+   info_ptr->valid |= PNG_INFO_sBIT;
+}
+#endif
+
+#if defined(PNG_sRGB_SUPPORTED)
+void PNGAPI
+png_set_sRGB(png_structp png_ptr, png_infop info_ptr, int intent)
+{
+   png_debug1(1, "in %s storage function\n", "sRGB");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   info_ptr->srgb_intent = (png_byte)intent;
+   info_ptr->valid |= PNG_INFO_sRGB;
+}
+
+void PNGAPI
+png_set_sRGB_gAMA_and_cHRM(png_structp png_ptr, png_infop info_ptr,
+   int intent)
+{
+#if defined(PNG_gAMA_SUPPORTED)
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+   float file_gamma;
+#endif
+#ifdef PNG_FIXED_POINT_SUPPORTED
+   png_fixed_point int_file_gamma;
+#endif
+#endif
+#if defined(PNG_cHRM_SUPPORTED)
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+   float white_x, white_y, red_x, red_y, green_x, green_y, blue_x, blue_y;
+#endif
+#ifdef PNG_FIXED_POINT_SUPPORTED
+   png_fixed_point int_white_x, int_white_y, int_red_x, int_red_y, int_green_x,
+      int_green_y, int_blue_x, int_blue_y;
+#endif
+#endif
+   png_debug1(1, "in %s storage function\n", "sRGB_gAMA_and_cHRM");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   png_set_sRGB(png_ptr, info_ptr, intent);
+
+#if defined(PNG_gAMA_SUPPORTED)
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+   file_gamma = (float).45455;
+   png_set_gAMA(png_ptr, info_ptr, file_gamma);
+#endif
+#ifdef PNG_FIXED_POINT_SUPPORTED
+   int_file_gamma = 45455L;
+   png_set_gAMA_fixed(png_ptr, info_ptr, int_file_gamma);
+#endif
+#endif
+
+#if defined(PNG_cHRM_SUPPORTED)
+#ifdef PNG_FIXED_POINT_SUPPORTED
+   int_white_x = 31270L;
+   int_white_y = 32900L;
+   int_red_x   = 64000L;
+   int_red_y   = 33000L;
+   int_green_x = 30000L;
+   int_green_y = 60000L;
+   int_blue_x  = 15000L;
+   int_blue_y  =  6000L;
+
+   png_set_cHRM_fixed(png_ptr, info_ptr,
+      int_white_x, int_white_y, int_red_x, int_red_y, int_green_x, int_green_y,
+      int_blue_x, int_blue_y);
+#endif
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+   white_x = (float).3127;
+   white_y = (float).3290;
+   red_x   = (float).64;
+   red_y   = (float).33;
+   green_x = (float).30;
+   green_y = (float).60;
+   blue_x  = (float).15;
+   blue_y  = (float).06;
+
+   png_set_cHRM(png_ptr, info_ptr,
+      white_x, white_y, red_x, red_y, green_x, green_y, blue_x, blue_y);
+#endif
+#endif
+}
+#endif
+
+
+#if defined(PNG_iCCP_SUPPORTED)
+void PNGAPI
+png_set_iCCP(png_structp png_ptr, png_infop info_ptr,
+             png_charp name, int compression_type,
+             png_charp profile, png_uint_32 proflen)
+{
+   png_charp new_iccp_name;
+   png_charp new_iccp_profile;
+
+   png_debug1(1, "in %s storage function\n", "iCCP");
+   if (png_ptr == NULL || info_ptr == NULL || name == NULL || profile == NULL)
+      return;
+
+   new_iccp_name = (png_charp)png_malloc_warn(png_ptr, png_strlen(name)+1);
+   if (new_iccp_name == NULL)
+   {
+      png_warning(png_ptr, "Insufficient memory to process iCCP chunk.");
+      return;
+   }
+   png_strncpy(new_iccp_name, name, png_sizeof(new_iccp_name));
+   new_iccp_profile = (png_charp)png_malloc_warn(png_ptr, proflen);
+   if (new_iccp_profile == NULL)
+   {
+      png_free (png_ptr, new_iccp_name);
+      png_warning(png_ptr, "Insufficient memory to process iCCP profile.");
+      return;
+   }
+   png_memcpy(new_iccp_profile, profile, (png_size_t)proflen);
+
+   png_free_data(png_ptr, info_ptr, PNG_FREE_ICCP, 0);
+
+   info_ptr->iccp_proflen = proflen;
+   info_ptr->iccp_name = new_iccp_name;
+   info_ptr->iccp_profile = new_iccp_profile;
+   /* Compression is always zero but is here so the API and info structure
+    * does not have to change if we introduce multiple compression types */
+   info_ptr->iccp_compression = (png_byte)compression_type;
+#ifdef PNG_FREE_ME_SUPPORTED
+   info_ptr->free_me |= PNG_FREE_ICCP;
+#endif
+   info_ptr->valid |= PNG_INFO_iCCP;
+}
+#endif
+
+#if defined(PNG_TEXT_SUPPORTED)
+void PNGAPI
+png_set_text(png_structp png_ptr, png_infop info_ptr, png_textp text_ptr,
+   int num_text)
+{
+   int ret;
+   ret=png_set_text_2(png_ptr, info_ptr, text_ptr, num_text);
+   if (ret)
+     png_error(png_ptr, "Insufficient memory to store text");
+}
+
+int /* PRIVATE */
+png_set_text_2(png_structp png_ptr, png_infop info_ptr, png_textp text_ptr,
+   int num_text)
+{
+   int i;
+
+   png_debug1(1, "in %s storage function\n", (png_ptr->chunk_name[0] == '\0' ?
+      "text" : (png_const_charp)png_ptr->chunk_name));
+
+   if (png_ptr == NULL || info_ptr == NULL || num_text == 0)
+      return(0);
+
+   /* Make sure we have enough space in the "text" array in info_struct
+    * to hold all of the incoming text_ptr objects.
+    */
+   if (info_ptr->num_text + num_text > info_ptr->max_text)
+   {
+      if (info_ptr->text != NULL)
+      {
+         png_textp old_text;
+         int old_max;
+
+         old_max = info_ptr->max_text;
+         info_ptr->max_text = info_ptr->num_text + num_text + 8;
+         old_text = info_ptr->text;
+         info_ptr->text = (png_textp)png_malloc_warn(png_ptr,
+            (png_uint_32)(info_ptr->max_text * png_sizeof (png_text)));
+         if (info_ptr->text == NULL)
+           {
+             png_free(png_ptr, old_text);
+             return(1);
+           }
+         png_memcpy(info_ptr->text, old_text, (png_size_t)(old_max *
+            png_sizeof(png_text)));
+         png_free(png_ptr, old_text);
+      }
+      else
+      {
+         info_ptr->max_text = num_text + 8;
+         info_ptr->num_text = 0;
+         info_ptr->text = (png_textp)png_malloc_warn(png_ptr,
+            (png_uint_32)(info_ptr->max_text * png_sizeof (png_text)));
+         if (info_ptr->text == NULL)
+           return(1);
+#ifdef PNG_FREE_ME_SUPPORTED
+         info_ptr->free_me |= PNG_FREE_TEXT;
+#endif
+      }
+      png_debug1(3, "allocated %d entries for info_ptr->text\n",
+         info_ptr->max_text);
+   }
+   for (i = 0; i < num_text; i++)
+   {
+      png_size_t text_length,key_len;
+      png_size_t lang_len,lang_key_len;
+      png_textp textp = &(info_ptr->text[info_ptr->num_text]);
+
+      if (text_ptr[i].key == NULL)
+          continue;
+
+      key_len = png_strlen(text_ptr[i].key);
+
+      if(text_ptr[i].compression <= 0)
+      {
+        lang_len = 0;
+        lang_key_len = 0;
+      }
+      else
+#ifdef PNG_iTXt_SUPPORTED
+      {
+        /* set iTXt data */
+        if (text_ptr[i].lang != NULL)
+          lang_len = png_strlen(text_ptr[i].lang);
+        else
+          lang_len = 0;
+        if (text_ptr[i].lang_key != NULL)
+          lang_key_len = png_strlen(text_ptr[i].lang_key);
+        else
+          lang_key_len = 0;
+      }
+#else
+      {
+        png_warning(png_ptr, "iTXt chunk not supported.");
+        continue;
+      }
+#endif
+
+      if (text_ptr[i].text == NULL || text_ptr[i].text[0] == '\0')
+      {
+         text_length = 0;
+#ifdef PNG_iTXt_SUPPORTED
+         if(text_ptr[i].compression > 0)
+            textp->compression = PNG_ITXT_COMPRESSION_NONE;
+         else
+#endif
+            textp->compression = PNG_TEXT_COMPRESSION_NONE;
+      }
+      else
+      {
+         text_length = png_strlen(text_ptr[i].text);
+         textp->compression = text_ptr[i].compression;
+      }
+
+      textp->key = (png_charp)png_malloc_warn(png_ptr,
+         (png_uint_32)(key_len + text_length + lang_len + lang_key_len + 4));
+      if (textp->key == NULL)
+        return(1);
+      png_debug2(2, "Allocated %lu bytes at %x in png_set_text\n",
+         (png_uint_32)(key_len + lang_len + lang_key_len + text_length + 4),
+         (int)textp->key);
+
+      png_memcpy(textp->key, text_ptr[i].key,
+         (png_size_t)(key_len));
+      *(textp->key+key_len) = '\0';
+#ifdef PNG_iTXt_SUPPORTED
+      if (text_ptr[i].compression > 0)
+      {
+         textp->lang=textp->key + key_len + 1;
+         png_memcpy(textp->lang, text_ptr[i].lang, lang_len);
+         *(textp->lang+lang_len) = '\0';
+         textp->lang_key=textp->lang + lang_len + 1;
+         png_memcpy(textp->lang_key, text_ptr[i].lang_key, lang_key_len);
+         *(textp->lang_key+lang_key_len) = '\0';
+         textp->text=textp->lang_key + lang_key_len + 1;
+      }
+      else
+#endif
+      {
+#ifdef PNG_iTXt_SUPPORTED
+         textp->lang=NULL;
+         textp->lang_key=NULL;
+#endif
+         textp->text=textp->key + key_len + 1;
+      }
+      if(text_length)
+         png_memcpy(textp->text, text_ptr[i].text,
+            (png_size_t)(text_length));
+      *(textp->text+text_length) = '\0';
+
+#ifdef PNG_iTXt_SUPPORTED
+      if(textp->compression > 0)
+      {
+         textp->text_length = 0;
+         textp->itxt_length = text_length;
+      }
+      else
+#endif
+      {
+         textp->text_length = text_length;
+#ifdef PNG_iTXt_SUPPORTED
+         textp->itxt_length = 0;
+#endif
+      }
+      info_ptr->num_text++;
+      png_debug1(3, "transferred text chunk %d\n", info_ptr->num_text);
+   }
+   return(0);
+}
+#endif
+
+#if defined(PNG_tIME_SUPPORTED)
+void PNGAPI
+png_set_tIME(png_structp png_ptr, png_infop info_ptr, png_timep mod_time)
+{
+   png_debug1(1, "in %s storage function\n", "tIME");
+   if (png_ptr == NULL || info_ptr == NULL ||
+       (png_ptr->mode & PNG_WROTE_tIME))
+      return;
+
+   png_memcpy(&(info_ptr->mod_time), mod_time, png_sizeof (png_time));
+   info_ptr->valid |= PNG_INFO_tIME;
+}
+#endif
+
+#if defined(PNG_tRNS_SUPPORTED)
+void PNGAPI
+png_set_tRNS(png_structp png_ptr, png_infop info_ptr,
+   png_bytep trans, int num_trans, png_color_16p trans_values)
+{
+   png_debug1(1, "in %s storage function\n", "tRNS");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   if (trans != NULL)
+   {
+       /*
+        * It may not actually be necessary to set png_ptr->trans here;
+        * we do it for backward compatibility with the way the png_handle_tRNS
+        * function used to do the allocation.
+        */
+#ifdef PNG_FREE_ME_SUPPORTED
+       png_free_data(png_ptr, info_ptr, PNG_FREE_TRNS, 0);
+#endif
+       /* Changed from num_trans to PNG_MAX_PALETTE_LENGTH in version 1.2.1 */
+       png_ptr->trans = info_ptr->trans = (png_bytep)png_malloc(png_ptr,
+           (png_uint_32)PNG_MAX_PALETTE_LENGTH);
+       if (num_trans <= PNG_MAX_PALETTE_LENGTH)
+         png_memcpy(info_ptr->trans, trans, (png_size_t)num_trans);
+#ifdef PNG_FREE_ME_SUPPORTED
+       info_ptr->free_me |= PNG_FREE_TRNS;
+#else
+       png_ptr->flags |= PNG_FLAG_FREE_TRNS;
+#endif
+   }
+
+   if (trans_values != NULL)
+   {
+      png_memcpy(&(info_ptr->trans_values), trans_values,
+         png_sizeof(png_color_16));
+      if (num_trans == 0)
+        num_trans = 1;
+   }
+   info_ptr->num_trans = (png_uint_16)num_trans;
+   info_ptr->valid |= PNG_INFO_tRNS;
+}
+#endif
+
+#if defined(PNG_sPLT_SUPPORTED)
+void PNGAPI
+png_set_sPLT(png_structp png_ptr,
+             png_infop info_ptr, png_sPLT_tp entries, int nentries)
+{
+    png_sPLT_tp np;
+    int i;
+
+    if (png_ptr == NULL || info_ptr == NULL)
+       return;
+
+    np = (png_sPLT_tp)png_malloc_warn(png_ptr,
+        (info_ptr->splt_palettes_num + nentries) * png_sizeof(png_sPLT_t));
+    if (np == NULL)
+    {
+      png_warning(png_ptr, "No memory for sPLT palettes.");
+      return;
+    }
+
+    png_memcpy(np, info_ptr->splt_palettes,
+           info_ptr->splt_palettes_num * png_sizeof(png_sPLT_t));
+    png_free(png_ptr, info_ptr->splt_palettes);
+    info_ptr->splt_palettes=NULL;
+
+    for (i = 0; i < nentries; i++)
+    {
+        png_sPLT_tp to = np + info_ptr->splt_palettes_num + i;
+        png_sPLT_tp from = entries + i;
+
+        to->name = (png_charp)png_malloc_warn(png_ptr,
+          png_strlen(from->name) + 1);
+        if (to->name == NULL)
+        {
+           png_warning(png_ptr,
+             "Out of memory while processing sPLT chunk");
+        }
+        /* TODO: use png_malloc_warn */
+        png_strncpy(to->name, from->name, png_strlen(from->name));
+        to->entries = (png_sPLT_entryp)png_malloc_warn(png_ptr,
+            from->nentries * png_sizeof(png_sPLT_entry));
+        /* TODO: use png_malloc_warn */
+        png_memcpy(to->entries, from->entries,
+            from->nentries * png_sizeof(png_sPLT_entry));
+        if (to->entries == NULL)
+        {
+           png_warning(png_ptr,
+             "Out of memory while processing sPLT chunk");
+           png_free(png_ptr,to->name);
+           to->name = NULL;
+        }
+        to->nentries = from->nentries;
+        to->depth = from->depth;
+    }
+
+    info_ptr->splt_palettes = np;
+    info_ptr->splt_palettes_num += nentries;
+    info_ptr->valid |= PNG_INFO_sPLT;
+#ifdef PNG_FREE_ME_SUPPORTED
+    info_ptr->free_me |= PNG_FREE_SPLT;
+#endif
+}
+#endif /* PNG_sPLT_SUPPORTED */
+
+#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+void PNGAPI
+png_set_unknown_chunks(png_structp png_ptr,
+   png_infop info_ptr, png_unknown_chunkp unknowns, int num_unknowns)
+{
+    png_unknown_chunkp np;
+    int i;
+
+    if (png_ptr == NULL || info_ptr == NULL || num_unknowns == 0)
+        return;
+
+    np = (png_unknown_chunkp)png_malloc_warn(png_ptr,
+        (info_ptr->unknown_chunks_num + num_unknowns) *
+        png_sizeof(png_unknown_chunk));
+    if (np == NULL)
+    {
+       png_warning(png_ptr,
+          "Out of memory while processing unknown chunk.");
+       return;
+    }
+
+    png_memcpy(np, info_ptr->unknown_chunks,
+           info_ptr->unknown_chunks_num * png_sizeof(png_unknown_chunk));
+    png_free(png_ptr, info_ptr->unknown_chunks);
+    info_ptr->unknown_chunks=NULL;
+
+    for (i = 0; i < num_unknowns; i++)
+    {
+        png_unknown_chunkp to = np + info_ptr->unknown_chunks_num + i;
+        png_unknown_chunkp from = unknowns + i;
+
+        png_strncpy((png_charp)to->name, (png_charp)from->name, 5);
+        to->data = (png_bytep)png_malloc_warn(png_ptr, from->size);
+        if (to->data == NULL)
+        {
+           png_warning(png_ptr,
+              "Out of memory while processing unknown chunk.");
+        }
+        else
+        {
+           png_memcpy(to->data, from->data, from->size);
+           to->size = from->size;
+
+           /* note our location in the read or write sequence */
+           to->location = (png_byte)(png_ptr->mode & 0xff);
+        }
+    }
+
+    info_ptr->unknown_chunks = np;
+    info_ptr->unknown_chunks_num += num_unknowns;
+#ifdef PNG_FREE_ME_SUPPORTED
+    info_ptr->free_me |= PNG_FREE_UNKN;
+#endif
+}
+void PNGAPI
+png_set_unknown_chunk_location(png_structp png_ptr, png_infop info_ptr,
+   int chunk, int location)
+{
+   if(png_ptr != NULL && info_ptr != NULL && chunk >= 0 && chunk <
+         (int)info_ptr->unknown_chunks_num)
+      info_ptr->unknown_chunks[chunk].location = (png_byte)location;
+}
+#endif
+
+#if defined(PNG_1_0_X) || defined(PNG_1_2_X)
+#if defined(PNG_READ_EMPTY_PLTE_SUPPORTED) || \
+    defined(PNG_WRITE_EMPTY_PLTE_SUPPORTED)
+void PNGAPI
+png_permit_empty_plte (png_structp png_ptr, int empty_plte_permitted)
+{
+   /* This function is deprecated in favor of png_permit_mng_features()
+      and will be removed from libpng-1.3.0 */
+   png_debug(1, "in png_permit_empty_plte, DEPRECATED.\n");
+   if (png_ptr == NULL)
+      return;
+   png_ptr->mng_features_permitted = (png_byte)
+     ((png_ptr->mng_features_permitted & (~(PNG_FLAG_MNG_EMPTY_PLTE))) |
+     ((empty_plte_permitted & PNG_FLAG_MNG_EMPTY_PLTE)));
+}
+#endif
+#endif
+
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
+png_uint_32 PNGAPI
+png_permit_mng_features (png_structp png_ptr, png_uint_32 mng_features)
+{
+   png_debug(1, "in png_permit_mng_features\n");
+   if (png_ptr == NULL)
+      return (png_uint_32)0;
+   png_ptr->mng_features_permitted =
+     (png_byte)(mng_features & PNG_ALL_MNG_FEATURES);
+   return (png_uint_32)png_ptr->mng_features_permitted;
+}
+#endif
+
+#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+void PNGAPI
+png_set_keep_unknown_chunks(png_structp png_ptr, int keep, png_bytep
+   chunk_list, int num_chunks)
+{
+    png_bytep new_list, p;
+    int i, old_num_chunks;
+    if (png_ptr == NULL)
+       return;
+    if (num_chunks == 0)
+    {
+      if(keep == PNG_HANDLE_CHUNK_ALWAYS || keep == PNG_HANDLE_CHUNK_IF_SAFE)
+        png_ptr->flags |= PNG_FLAG_KEEP_UNKNOWN_CHUNKS;
+      else
+        png_ptr->flags &= ~PNG_FLAG_KEEP_UNKNOWN_CHUNKS;
+
+      if(keep == PNG_HANDLE_CHUNK_ALWAYS)
+        png_ptr->flags |= PNG_FLAG_KEEP_UNSAFE_CHUNKS;
+      else
+        png_ptr->flags &= ~PNG_FLAG_KEEP_UNSAFE_CHUNKS;
+      return;
+    }
+    if (chunk_list == NULL)
+      return;
+    old_num_chunks=png_ptr->num_chunk_list;
+    new_list=(png_bytep)png_malloc(png_ptr,
+       (png_uint_32)(5*(num_chunks+old_num_chunks)));
+    if(png_ptr->chunk_list != NULL)
+    {
+       png_memcpy(new_list, png_ptr->chunk_list,
+          (png_size_t)(5*old_num_chunks));
+       png_free(png_ptr, png_ptr->chunk_list);
+       png_ptr->chunk_list=NULL;
+    }
+    png_memcpy(new_list+5*old_num_chunks, chunk_list,
+       (png_size_t)(5*num_chunks));
+    for (p=new_list+5*old_num_chunks+4, i=0; i<num_chunks; i++, p+=5)
+       *p=(png_byte)keep;
+    png_ptr->num_chunk_list=old_num_chunks+num_chunks;
+    png_ptr->chunk_list=new_list;
+#ifdef PNG_FREE_ME_SUPPORTED
+    png_ptr->free_me |= PNG_FREE_LIST;
+#endif
+}
+#endif
+
+#if defined(PNG_READ_USER_CHUNKS_SUPPORTED)
+void PNGAPI
+png_set_read_user_chunk_fn(png_structp png_ptr, png_voidp user_chunk_ptr,
+   png_user_chunk_ptr read_user_chunk_fn)
+{
+   png_debug(1, "in png_set_read_user_chunk_fn\n");
+   if (png_ptr == NULL)
+      return;
+   png_ptr->read_user_chunk_fn = read_user_chunk_fn;
+   png_ptr->user_chunk_ptr = user_chunk_ptr;
+}
+#endif
+
+#if defined(PNG_INFO_IMAGE_SUPPORTED)
+void PNGAPI
+png_set_rows(png_structp png_ptr, png_infop info_ptr, png_bytepp row_pointers)
+{
+   png_debug1(1, "in %s storage function\n", "rows");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   if(info_ptr->row_pointers && (info_ptr->row_pointers != row_pointers))
+      png_free_data(png_ptr, info_ptr, PNG_FREE_ROWS, 0);
+   info_ptr->row_pointers = row_pointers;
+   if(row_pointers)
+      info_ptr->valid |= PNG_INFO_IDAT;
+}
+#endif
+
+#ifdef PNG_WRITE_SUPPORTED
+void PNGAPI
+png_set_compression_buffer_size(png_structp png_ptr, png_uint_32 size)
+{
+    if (png_ptr == NULL)
+       return;
+    if(png_ptr->zbuf)
+       png_free(png_ptr, png_ptr->zbuf);
+    png_ptr->zbuf_size = (png_size_t)size;
+    png_ptr->zbuf = (png_bytep)png_malloc(png_ptr, size);
+    png_ptr->zstream.next_out = png_ptr->zbuf;
+    png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+}
+#endif
+
+void PNGAPI
+png_set_invalid(png_structp png_ptr, png_infop info_ptr, int mask)
+{
+   if (png_ptr && info_ptr)
+      info_ptr->valid &= ~(mask);
+}
+
+
+#ifndef PNG_1_0_X
+#ifdef PNG_ASSEMBLER_CODE_SUPPORTED
+/* this function was added to libpng 1.2.0 and should always exist by default */
+void PNGAPI
+png_set_asm_flags (png_structp png_ptr, png_uint_32 asm_flags)
+{
+#ifdef PNG_MMX_CODE_SUPPORTED
+    png_uint_32 settable_asm_flags;
+    png_uint_32 settable_mmx_flags;
+#endif
+    if (png_ptr == NULL)
+       return;
+#ifdef PNG_MMX_CODE_SUPPORTED
+
+    settable_mmx_flags =
+#ifdef PNG_HAVE_MMX_COMBINE_ROW
+                         PNG_ASM_FLAG_MMX_READ_COMBINE_ROW  |
+#endif
+#ifdef PNG_HAVE_MMX_READ_INTERLACE
+                         PNG_ASM_FLAG_MMX_READ_INTERLACE    |
+#endif
+#ifdef PNG_HAVE_MMX_READ_FILTER_ROW
+                         PNG_ASM_FLAG_MMX_READ_FILTER_SUB   |
+                         PNG_ASM_FLAG_MMX_READ_FILTER_UP    |
+                         PNG_ASM_FLAG_MMX_READ_FILTER_AVG   |
+                         PNG_ASM_FLAG_MMX_READ_FILTER_PAETH |
+#endif
+                         0;
+
+    /* could be some non-MMX ones in the future, but not currently: */
+    settable_asm_flags = settable_mmx_flags;
+
+    if (!(png_ptr->asm_flags & PNG_ASM_FLAG_MMX_SUPPORT_COMPILED) ||
+        !(png_ptr->asm_flags & PNG_ASM_FLAG_MMX_SUPPORT_IN_CPU))
+    {
+        /* clear all MMX flags if MMX isn't supported */
+        settable_asm_flags &= ~settable_mmx_flags;
+        png_ptr->asm_flags &= ~settable_mmx_flags;
+    }
+
+    /* we're replacing the settable bits with those passed in by the user,
+     * so first zero them out of the master copy, then bitwise-OR in the
+     * allowed subset that was requested */
+
+    png_ptr->asm_flags &= ~settable_asm_flags;               /* zero them */
+    png_ptr->asm_flags |= (asm_flags & settable_asm_flags);  /* set them */
+#endif /* ?PNG_MMX_CODE_SUPPORTED */
+}
+
+/* this function was added to libpng 1.2.0 */
+void PNGAPI
+png_set_mmx_thresholds (png_structp png_ptr,
+                        png_byte mmx_bitdepth_threshold,
+                        png_uint_32 mmx_rowbytes_threshold)
+{
+    if (png_ptr == NULL)
+       return;
+#ifdef PNG_MMX_CODE_SUPPORTED
+    png_ptr->mmx_bitdepth_threshold = mmx_bitdepth_threshold;
+    png_ptr->mmx_rowbytes_threshold = mmx_rowbytes_threshold;
+#endif /* ?PNG_MMX_CODE_SUPPORTED */
+}
+#endif /* ?PNG_ASSEMBLER_CODE_SUPPORTED */
+
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+/* this function was added to libpng 1.2.6 */
+void PNGAPI
+png_set_user_limits (png_structp png_ptr, png_uint_32 user_width_max,
+    png_uint_32 user_height_max)
+{
+    /* Images with dimensions larger than these limits will be
+     * rejected by png_set_IHDR().  To accept any PNG datastream
+     * regardless of dimensions, set both limits to 0x7ffffffL.
+     */
+    if(png_ptr == NULL) return;
+    png_ptr->user_width_max = user_width_max;
+    png_ptr->user_height_max = user_height_max;
+}
+#endif /* ?PNG_SET_USER_LIMITS_SUPPORTED */
+
+#endif /* ?PNG_1_0_X */
+#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
diff --git a/distrib/libpng-1.2.19/pngtrans.c b/distrib/libpng-1.2.19/pngtrans.c
new file mode 100644
index 0000000..1640095
--- /dev/null
+++ b/distrib/libpng-1.2.19/pngtrans.c
@@ -0,0 +1,662 @@
+
+/* pngtrans.c - transforms the data in a row (used by both readers and writers)
+ *
+ * Last changed in libpng 1.2.17 May 15, 2007
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1998-2007 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ */
+
+#define PNG_INTERNAL
+#include "png.h"
+
+#if defined(PNG_READ_SUPPORTED) || defined(PNG_WRITE_SUPPORTED)
+#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
+/* turn on BGR-to-RGB mapping */
+void PNGAPI
+png_set_bgr(png_structp png_ptr)
+{
+   png_debug(1, "in png_set_bgr\n");
+   if(png_ptr == NULL) return;
+   png_ptr->transformations |= PNG_BGR;
+}
+#endif
+
+#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
+/* turn on 16 bit byte swapping */
+void PNGAPI
+png_set_swap(png_structp png_ptr)
+{
+   png_debug(1, "in png_set_swap\n");
+   if(png_ptr == NULL) return;
+   if (png_ptr->bit_depth == 16)
+      png_ptr->transformations |= PNG_SWAP_BYTES;
+}
+#endif
+
+#if defined(PNG_READ_PACK_SUPPORTED) || defined(PNG_WRITE_PACK_SUPPORTED)
+/* turn on pixel packing */
+void PNGAPI
+png_set_packing(png_structp png_ptr)
+{
+   png_debug(1, "in png_set_packing\n");
+   if(png_ptr == NULL) return;
+   if (png_ptr->bit_depth < 8)
+   {
+      png_ptr->transformations |= PNG_PACK;
+      png_ptr->usr_bit_depth = 8;
+   }
+}
+#endif
+
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED)
+/* turn on packed pixel swapping */
+void PNGAPI
+png_set_packswap(png_structp png_ptr)
+{
+   png_debug(1, "in png_set_packswap\n");
+   if(png_ptr == NULL) return;
+   if (png_ptr->bit_depth < 8)
+      png_ptr->transformations |= PNG_PACKSWAP;
+}
+#endif
+
+#if defined(PNG_READ_SHIFT_SUPPORTED) || defined(PNG_WRITE_SHIFT_SUPPORTED)
+void PNGAPI
+png_set_shift(png_structp png_ptr, png_color_8p true_bits)
+{
+   png_debug(1, "in png_set_shift\n");
+   if(png_ptr == NULL) return;
+   png_ptr->transformations |= PNG_SHIFT;
+   png_ptr->shift = *true_bits;
+}
+#endif
+
+#if defined(PNG_READ_INTERLACING_SUPPORTED) || \
+    defined(PNG_WRITE_INTERLACING_SUPPORTED)
+int PNGAPI
+png_set_interlace_handling(png_structp png_ptr)
+{
+   png_debug(1, "in png_set_interlace handling\n");
+   if (png_ptr && png_ptr->interlaced)
+   {
+      png_ptr->transformations |= PNG_INTERLACE;
+      return (7);
+   }
+
+   return (1);
+}
+#endif
+
+#if defined(PNG_READ_FILLER_SUPPORTED) || defined(PNG_WRITE_FILLER_SUPPORTED)
+/* Add a filler byte on read, or remove a filler or alpha byte on write.
+ * The filler type has changed in v0.95 to allow future 2-byte fillers
+ * for 48-bit input data, as well as to avoid problems with some compilers
+ * that don't like bytes as parameters.
+ */
+void PNGAPI
+png_set_filler(png_structp png_ptr, png_uint_32 filler, int filler_loc)
+{
+   png_debug(1, "in png_set_filler\n");
+   if(png_ptr == NULL) return;
+   png_ptr->transformations |= PNG_FILLER;
+   png_ptr->filler = (png_byte)filler;
+   if (filler_loc == PNG_FILLER_AFTER)
+      png_ptr->flags |= PNG_FLAG_FILLER_AFTER;
+   else
+      png_ptr->flags &= ~PNG_FLAG_FILLER_AFTER;
+
+   /* This should probably go in the "do_read_filler" routine.
+    * I attempted to do that in libpng-1.0.1a but that caused problems
+    * so I restored it in libpng-1.0.2a
+   */
+
+   if (png_ptr->color_type == PNG_COLOR_TYPE_RGB)
+   {
+      png_ptr->usr_channels = 4;
+   }
+
+   /* Also I added this in libpng-1.0.2a (what happens when we expand
+    * a less-than-8-bit grayscale to GA? */
+
+   if (png_ptr->color_type == PNG_COLOR_TYPE_GRAY && png_ptr->bit_depth >= 8)
+   {
+      png_ptr->usr_channels = 2;
+   }
+}
+
+#if !defined(PNG_1_0_X)
+/* Added to libpng-1.2.7 */
+void PNGAPI
+png_set_add_alpha(png_structp png_ptr, png_uint_32 filler, int filler_loc)
+{
+   png_debug(1, "in png_set_add_alpha\n");
+   if(png_ptr == NULL) return;
+   png_set_filler(png_ptr, filler, filler_loc);
+   png_ptr->transformations |= PNG_ADD_ALPHA;
+}
+#endif
+
+#endif
+
+#if defined(PNG_READ_SWAP_ALPHA_SUPPORTED) || \
+    defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
+void PNGAPI
+png_set_swap_alpha(png_structp png_ptr)
+{
+   png_debug(1, "in png_set_swap_alpha\n");
+   if(png_ptr == NULL) return;
+   png_ptr->transformations |= PNG_SWAP_ALPHA;
+}
+#endif
+
+#if defined(PNG_READ_INVERT_ALPHA_SUPPORTED) || \
+    defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
+void PNGAPI
+png_set_invert_alpha(png_structp png_ptr)
+{
+   png_debug(1, "in png_set_invert_alpha\n");
+   if(png_ptr == NULL) return;
+   png_ptr->transformations |= PNG_INVERT_ALPHA;
+}
+#endif
+
+#if defined(PNG_READ_INVERT_SUPPORTED) || defined(PNG_WRITE_INVERT_SUPPORTED)
+void PNGAPI
+png_set_invert_mono(png_structp png_ptr)
+{
+   png_debug(1, "in png_set_invert_mono\n");
+   if(png_ptr == NULL) return;
+   png_ptr->transformations |= PNG_INVERT_MONO;
+}
+
+/* invert monochrome grayscale data */
+void /* PRIVATE */
+png_do_invert(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_invert\n");
+  /* This test removed from libpng version 1.0.13 and 1.2.0:
+   *   if (row_info->bit_depth == 1 &&
+   */
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+   if (row == NULL || row_info == NULL)
+     return;
+#endif
+   if (row_info->color_type == PNG_COLOR_TYPE_GRAY)
+   {
+      png_bytep rp = row;
+      png_uint_32 i;
+      png_uint_32 istop = row_info->rowbytes;
+
+      for (i = 0; i < istop; i++)
+      {
+         *rp = (png_byte)(~(*rp));
+         rp++;
+      }
+   }
+   else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA &&
+      row_info->bit_depth == 8)
+   {
+      png_bytep rp = row;
+      png_uint_32 i;
+      png_uint_32 istop = row_info->rowbytes;
+
+      for (i = 0; i < istop; i+=2)
+      {
+         *rp = (png_byte)(~(*rp));
+         rp+=2;
+      }
+   }
+   else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA &&
+      row_info->bit_depth == 16)
+   {
+      png_bytep rp = row;
+      png_uint_32 i;
+      png_uint_32 istop = row_info->rowbytes;
+
+      for (i = 0; i < istop; i+=4)
+      {
+         *rp = (png_byte)(~(*rp));
+         *(rp+1) = (png_byte)(~(*(rp+1)));
+         rp+=4;
+      }
+   }
+}
+#endif
+
+#if defined(PNG_READ_SWAP_SUPPORTED) || defined(PNG_WRITE_SWAP_SUPPORTED)
+/* swaps byte order on 16 bit depth images */
+void /* PRIVATE */
+png_do_swap(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_swap\n");
+   if (
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+       row != NULL && row_info != NULL &&
+#endif
+       row_info->bit_depth == 16)
+   {
+      png_bytep rp = row;
+      png_uint_32 i;
+      png_uint_32 istop= row_info->width * row_info->channels;
+
+      for (i = 0; i < istop; i++, rp += 2)
+      {
+         png_byte t = *rp;
+         *rp = *(rp + 1);
+         *(rp + 1) = t;
+      }
+   }
+}
+#endif
+
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)||defined(PNG_WRITE_PACKSWAP_SUPPORTED)
+static PNG_CONST png_byte onebppswaptable[256] = {
+   0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0,
+   0x10, 0x90, 0x50, 0xD0, 0x30, 0xB0, 0x70, 0xF0,
+   0x08, 0x88, 0x48, 0xC8, 0x28, 0xA8, 0x68, 0xE8,
+   0x18, 0x98, 0x58, 0xD8, 0x38, 0xB8, 0x78, 0xF8,
+   0x04, 0x84, 0x44, 0xC4, 0x24, 0xA4, 0x64, 0xE4,
+   0x14, 0x94, 0x54, 0xD4, 0x34, 0xB4, 0x74, 0xF4,
+   0x0C, 0x8C, 0x4C, 0xCC, 0x2C, 0xAC, 0x6C, 0xEC,
+   0x1C, 0x9C, 0x5C, 0xDC, 0x3C, 0xBC, 0x7C, 0xFC,
+   0x02, 0x82, 0x42, 0xC2, 0x22, 0xA2, 0x62, 0xE2,
+   0x12, 0x92, 0x52, 0xD2, 0x32, 0xB2, 0x72, 0xF2,
+   0x0A, 0x8A, 0x4A, 0xCA, 0x2A, 0xAA, 0x6A, 0xEA,
+   0x1A, 0x9A, 0x5A, 0xDA, 0x3A, 0xBA, 0x7A, 0xFA,
+   0x06, 0x86, 0x46, 0xC6, 0x26, 0xA6, 0x66, 0xE6,
+   0x16, 0x96, 0x56, 0xD6, 0x36, 0xB6, 0x76, 0xF6,
+   0x0E, 0x8E, 0x4E, 0xCE, 0x2E, 0xAE, 0x6E, 0xEE,
+   0x1E, 0x9E, 0x5E, 0xDE, 0x3E, 0xBE, 0x7E, 0xFE,
+   0x01, 0x81, 0x41, 0xC1, 0x21, 0xA1, 0x61, 0xE1,
+   0x11, 0x91, 0x51, 0xD1, 0x31, 0xB1, 0x71, 0xF1,
+   0x09, 0x89, 0x49, 0xC9, 0x29, 0xA9, 0x69, 0xE9,
+   0x19, 0x99, 0x59, 0xD9, 0x39, 0xB9, 0x79, 0xF9,
+   0x05, 0x85, 0x45, 0xC5, 0x25, 0xA5, 0x65, 0xE5,
+   0x15, 0x95, 0x55, 0xD5, 0x35, 0xB5, 0x75, 0xF5,
+   0x0D, 0x8D, 0x4D, 0xCD, 0x2D, 0xAD, 0x6D, 0xED,
+   0x1D, 0x9D, 0x5D, 0xDD, 0x3D, 0xBD, 0x7D, 0xFD,
+   0x03, 0x83, 0x43, 0xC3, 0x23, 0xA3, 0x63, 0xE3,
+   0x13, 0x93, 0x53, 0xD3, 0x33, 0xB3, 0x73, 0xF3,
+   0x0B, 0x8B, 0x4B, 0xCB, 0x2B, 0xAB, 0x6B, 0xEB,
+   0x1B, 0x9B, 0x5B, 0xDB, 0x3B, 0xBB, 0x7B, 0xFB,
+   0x07, 0x87, 0x47, 0xC7, 0x27, 0xA7, 0x67, 0xE7,
+   0x17, 0x97, 0x57, 0xD7, 0x37, 0xB7, 0x77, 0xF7,
+   0x0F, 0x8F, 0x4F, 0xCF, 0x2F, 0xAF, 0x6F, 0xEF,
+   0x1F, 0x9F, 0x5F, 0xDF, 0x3F, 0xBF, 0x7F, 0xFF
+};
+
+static PNG_CONST png_byte twobppswaptable[256] = {
+   0x00, 0x40, 0x80, 0xC0, 0x10, 0x50, 0x90, 0xD0,
+   0x20, 0x60, 0xA0, 0xE0, 0x30, 0x70, 0xB0, 0xF0,
+   0x04, 0x44, 0x84, 0xC4, 0x14, 0x54, 0x94, 0xD4,
+   0x24, 0x64, 0xA4, 0xE4, 0x34, 0x74, 0xB4, 0xF4,
+   0x08, 0x48, 0x88, 0xC8, 0x18, 0x58, 0x98, 0xD8,
+   0x28, 0x68, 0xA8, 0xE8, 0x38, 0x78, 0xB8, 0xF8,
+   0x0C, 0x4C, 0x8C, 0xCC, 0x1C, 0x5C, 0x9C, 0xDC,
+   0x2C, 0x6C, 0xAC, 0xEC, 0x3C, 0x7C, 0xBC, 0xFC,
+   0x01, 0x41, 0x81, 0xC1, 0x11, 0x51, 0x91, 0xD1,
+   0x21, 0x61, 0xA1, 0xE1, 0x31, 0x71, 0xB1, 0xF1,
+   0x05, 0x45, 0x85, 0xC5, 0x15, 0x55, 0x95, 0xD5,
+   0x25, 0x65, 0xA5, 0xE5, 0x35, 0x75, 0xB5, 0xF5,
+   0x09, 0x49, 0x89, 0xC9, 0x19, 0x59, 0x99, 0xD9,
+   0x29, 0x69, 0xA9, 0xE9, 0x39, 0x79, 0xB9, 0xF9,
+   0x0D, 0x4D, 0x8D, 0xCD, 0x1D, 0x5D, 0x9D, 0xDD,
+   0x2D, 0x6D, 0xAD, 0xED, 0x3D, 0x7D, 0xBD, 0xFD,
+   0x02, 0x42, 0x82, 0xC2, 0x12, 0x52, 0x92, 0xD2,
+   0x22, 0x62, 0xA2, 0xE2, 0x32, 0x72, 0xB2, 0xF2,
+   0x06, 0x46, 0x86, 0xC6, 0x16, 0x56, 0x96, 0xD6,
+   0x26, 0x66, 0xA6, 0xE6, 0x36, 0x76, 0xB6, 0xF6,
+   0x0A, 0x4A, 0x8A, 0xCA, 0x1A, 0x5A, 0x9A, 0xDA,
+   0x2A, 0x6A, 0xAA, 0xEA, 0x3A, 0x7A, 0xBA, 0xFA,
+   0x0E, 0x4E, 0x8E, 0xCE, 0x1E, 0x5E, 0x9E, 0xDE,
+   0x2E, 0x6E, 0xAE, 0xEE, 0x3E, 0x7E, 0xBE, 0xFE,
+   0x03, 0x43, 0x83, 0xC3, 0x13, 0x53, 0x93, 0xD3,
+   0x23, 0x63, 0xA3, 0xE3, 0x33, 0x73, 0xB3, 0xF3,
+   0x07, 0x47, 0x87, 0xC7, 0x17, 0x57, 0x97, 0xD7,
+   0x27, 0x67, 0xA7, 0xE7, 0x37, 0x77, 0xB7, 0xF7,
+   0x0B, 0x4B, 0x8B, 0xCB, 0x1B, 0x5B, 0x9B, 0xDB,
+   0x2B, 0x6B, 0xAB, 0xEB, 0x3B, 0x7B, 0xBB, 0xFB,
+   0x0F, 0x4F, 0x8F, 0xCF, 0x1F, 0x5F, 0x9F, 0xDF,
+   0x2F, 0x6F, 0xAF, 0xEF, 0x3F, 0x7F, 0xBF, 0xFF
+};
+
+static PNG_CONST png_byte fourbppswaptable[256] = {
+   0x00, 0x10, 0x20, 0x30, 0x40, 0x50, 0x60, 0x70,
+   0x80, 0x90, 0xA0, 0xB0, 0xC0, 0xD0, 0xE0, 0xF0,
+   0x01, 0x11, 0x21, 0x31, 0x41, 0x51, 0x61, 0x71,
+   0x81, 0x91, 0xA1, 0xB1, 0xC1, 0xD1, 0xE1, 0xF1,
+   0x02, 0x12, 0x22, 0x32, 0x42, 0x52, 0x62, 0x72,
+   0x82, 0x92, 0xA2, 0xB2, 0xC2, 0xD2, 0xE2, 0xF2,
+   0x03, 0x13, 0x23, 0x33, 0x43, 0x53, 0x63, 0x73,
+   0x83, 0x93, 0xA3, 0xB3, 0xC3, 0xD3, 0xE3, 0xF3,
+   0x04, 0x14, 0x24, 0x34, 0x44, 0x54, 0x64, 0x74,
+   0x84, 0x94, 0xA4, 0xB4, 0xC4, 0xD4, 0xE4, 0xF4,
+   0x05, 0x15, 0x25, 0x35, 0x45, 0x55, 0x65, 0x75,
+   0x85, 0x95, 0xA5, 0xB5, 0xC5, 0xD5, 0xE5, 0xF5,
+   0x06, 0x16, 0x26, 0x36, 0x46, 0x56, 0x66, 0x76,
+   0x86, 0x96, 0xA6, 0xB6, 0xC6, 0xD6, 0xE6, 0xF6,
+   0x07, 0x17, 0x27, 0x37, 0x47, 0x57, 0x67, 0x77,
+   0x87, 0x97, 0xA7, 0xB7, 0xC7, 0xD7, 0xE7, 0xF7,
+   0x08, 0x18, 0x28, 0x38, 0x48, 0x58, 0x68, 0x78,
+   0x88, 0x98, 0xA8, 0xB8, 0xC8, 0xD8, 0xE8, 0xF8,
+   0x09, 0x19, 0x29, 0x39, 0x49, 0x59, 0x69, 0x79,
+   0x89, 0x99, 0xA9, 0xB9, 0xC9, 0xD9, 0xE9, 0xF9,
+   0x0A, 0x1A, 0x2A, 0x3A, 0x4A, 0x5A, 0x6A, 0x7A,
+   0x8A, 0x9A, 0xAA, 0xBA, 0xCA, 0xDA, 0xEA, 0xFA,
+   0x0B, 0x1B, 0x2B, 0x3B, 0x4B, 0x5B, 0x6B, 0x7B,
+   0x8B, 0x9B, 0xAB, 0xBB, 0xCB, 0xDB, 0xEB, 0xFB,
+   0x0C, 0x1C, 0x2C, 0x3C, 0x4C, 0x5C, 0x6C, 0x7C,
+   0x8C, 0x9C, 0xAC, 0xBC, 0xCC, 0xDC, 0xEC, 0xFC,
+   0x0D, 0x1D, 0x2D, 0x3D, 0x4D, 0x5D, 0x6D, 0x7D,
+   0x8D, 0x9D, 0xAD, 0xBD, 0xCD, 0xDD, 0xED, 0xFD,
+   0x0E, 0x1E, 0x2E, 0x3E, 0x4E, 0x5E, 0x6E, 0x7E,
+   0x8E, 0x9E, 0xAE, 0xBE, 0xCE, 0xDE, 0xEE, 0xFE,
+   0x0F, 0x1F, 0x2F, 0x3F, 0x4F, 0x5F, 0x6F, 0x7F,
+   0x8F, 0x9F, 0xAF, 0xBF, 0xCF, 0xDF, 0xEF, 0xFF
+};
+
+/* swaps pixel packing order within bytes */
+void /* PRIVATE */
+png_do_packswap(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_packswap\n");
+   if (
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+       row != NULL && row_info != NULL &&
+#endif
+       row_info->bit_depth < 8)
+   {
+      png_bytep rp, end, table;
+
+      end = row + row_info->rowbytes;
+
+      if (row_info->bit_depth == 1)
+         table = (png_bytep)onebppswaptable;
+      else if (row_info->bit_depth == 2)
+         table = (png_bytep)twobppswaptable;
+      else if (row_info->bit_depth == 4)
+         table = (png_bytep)fourbppswaptable;
+      else
+         return;
+
+      for (rp = row; rp < end; rp++)
+         *rp = table[*rp];
+   }
+}
+#endif /* PNG_READ_PACKSWAP_SUPPORTED or PNG_WRITE_PACKSWAP_SUPPORTED */
+
+#if defined(PNG_WRITE_FILLER_SUPPORTED) || \
+    defined(PNG_READ_STRIP_ALPHA_SUPPORTED)
+/* remove filler or alpha byte(s) */
+void /* PRIVATE */
+png_do_strip_filler(png_row_infop row_info, png_bytep row, png_uint_32 flags)
+{
+   png_debug(1, "in png_do_strip_filler\n");
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+   if (row != NULL && row_info != NULL)
+#endif
+   {
+      png_bytep sp=row;
+      png_bytep dp=row;
+      png_uint_32 row_width=row_info->width;
+      png_uint_32 i;
+
+      if ((row_info->color_type == PNG_COLOR_TYPE_RGB ||
+         (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA &&
+         (flags & PNG_FLAG_STRIP_ALPHA))) &&
+         row_info->channels == 4)
+      {
+         if (row_info->bit_depth == 8)
+         {
+            /* This converts from RGBX or RGBA to RGB */
+            if (flags & PNG_FLAG_FILLER_AFTER)
+            {
+               dp+=3; sp+=4;
+               for (i = 1; i < row_width; i++)
+               {
+                  *dp++ = *sp++;
+                  *dp++ = *sp++;
+                  *dp++ = *sp++;
+                  sp++;
+               }
+            }
+            /* This converts from XRGB or ARGB to RGB */
+            else
+            {
+               for (i = 0; i < row_width; i++)
+               {
+                  sp++;
+                  *dp++ = *sp++;
+                  *dp++ = *sp++;
+                  *dp++ = *sp++;
+               }
+            }
+            row_info->pixel_depth = 24;
+            row_info->rowbytes = row_width * 3;
+         }
+         else /* if (row_info->bit_depth == 16) */
+         {
+            if (flags & PNG_FLAG_FILLER_AFTER)
+            {
+               /* This converts from RRGGBBXX or RRGGBBAA to RRGGBB */
+               sp += 8; dp += 6;
+               for (i = 1; i < row_width; i++)
+               {
+                  /* This could be (although png_memcpy is probably slower):
+                  png_memcpy(dp, sp, 6);
+                  sp += 8;
+                  dp += 6;
+                  */
+
+                  *dp++ = *sp++;
+                  *dp++ = *sp++;
+                  *dp++ = *sp++;
+                  *dp++ = *sp++;
+                  *dp++ = *sp++;
+                  *dp++ = *sp++;
+                  sp += 2;
+               }
+            }
+            else
+            {
+               /* This converts from XXRRGGBB or AARRGGBB to RRGGBB */
+               for (i = 0; i < row_width; i++)
+               {
+                  /* This could be (although png_memcpy is probably slower):
+                  png_memcpy(dp, sp, 6);
+                  sp += 8;
+                  dp += 6;
+                  */
+
+                  sp+=2;
+                  *dp++ = *sp++;
+                  *dp++ = *sp++;
+                  *dp++ = *sp++;
+                  *dp++ = *sp++;
+                  *dp++ = *sp++;
+                  *dp++ = *sp++;
+               }
+            }
+            row_info->pixel_depth = 48;
+            row_info->rowbytes = row_width * 6;
+         }
+         row_info->channels = 3;
+      }
+      else if ((row_info->color_type == PNG_COLOR_TYPE_GRAY ||
+         (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA &&
+         (flags & PNG_FLAG_STRIP_ALPHA))) &&
+          row_info->channels == 2)
+      {
+         if (row_info->bit_depth == 8)
+         {
+            /* This converts from GX or GA to G */
+            if (flags & PNG_FLAG_FILLER_AFTER)
+            {
+               for (i = 0; i < row_width; i++)
+               {
+                  *dp++ = *sp++;
+                  sp++;
+               }
+            }
+            /* This converts from XG or AG to G */
+            else
+            {
+               for (i = 0; i < row_width; i++)
+               {
+                  sp++;
+                  *dp++ = *sp++;
+               }
+            }
+            row_info->pixel_depth = 8;
+            row_info->rowbytes = row_width;
+         }
+         else /* if (row_info->bit_depth == 16) */
+         {
+            if (flags & PNG_FLAG_FILLER_AFTER)
+            {
+               /* This converts from GGXX or GGAA to GG */
+               sp += 4; dp += 2;
+               for (i = 1; i < row_width; i++)
+               {
+                  *dp++ = *sp++;
+                  *dp++ = *sp++;
+                  sp += 2;
+               }
+            }
+            else
+            {
+               /* This converts from XXGG or AAGG to GG */
+               for (i = 0; i < row_width; i++)
+               {
+                  sp += 2;
+                  *dp++ = *sp++;
+                  *dp++ = *sp++;
+               }
+            }
+            row_info->pixel_depth = 16;
+            row_info->rowbytes = row_width * 2;
+         }
+         row_info->channels = 1;
+      }
+      if (flags & PNG_FLAG_STRIP_ALPHA)
+        row_info->color_type &= ~PNG_COLOR_MASK_ALPHA;
+   }
+}
+#endif
+
+#if defined(PNG_READ_BGR_SUPPORTED) || defined(PNG_WRITE_BGR_SUPPORTED)
+/* swaps red and blue bytes within a pixel */
+void /* PRIVATE */
+png_do_bgr(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_bgr\n");
+   if (
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+       row != NULL && row_info != NULL &&
+#endif
+       (row_info->color_type & PNG_COLOR_MASK_COLOR))
+   {
+      png_uint_32 row_width = row_info->width;
+      if (row_info->bit_depth == 8)
+      {
+         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+         {
+            png_bytep rp;
+            png_uint_32 i;
+
+            for (i = 0, rp = row; i < row_width; i++, rp += 3)
+            {
+               png_byte save = *rp;
+               *rp = *(rp + 2);
+               *(rp + 2) = save;
+            }
+         }
+         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+         {
+            png_bytep rp;
+            png_uint_32 i;
+
+            for (i = 0, rp = row; i < row_width; i++, rp += 4)
+            {
+               png_byte save = *rp;
+               *rp = *(rp + 2);
+               *(rp + 2) = save;
+            }
+         }
+      }
+      else if (row_info->bit_depth == 16)
+      {
+         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+         {
+            png_bytep rp;
+            png_uint_32 i;
+
+            for (i = 0, rp = row; i < row_width; i++, rp += 6)
+            {
+               png_byte save = *rp;
+               *rp = *(rp + 4);
+               *(rp + 4) = save;
+               save = *(rp + 1);
+               *(rp + 1) = *(rp + 5);
+               *(rp + 5) = save;
+            }
+         }
+         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+         {
+            png_bytep rp;
+            png_uint_32 i;
+
+            for (i = 0, rp = row; i < row_width; i++, rp += 8)
+            {
+               png_byte save = *rp;
+               *rp = *(rp + 4);
+               *(rp + 4) = save;
+               save = *(rp + 1);
+               *(rp + 1) = *(rp + 5);
+               *(rp + 5) = save;
+            }
+         }
+      }
+   }
+}
+#endif /* PNG_READ_BGR_SUPPORTED or PNG_WRITE_BGR_SUPPORTED */
+
+#if defined(PNG_READ_USER_TRANSFORM_SUPPORTED) || \
+    defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED) || \
+    defined(PNG_LEGACY_SUPPORTED)
+void PNGAPI
+png_set_user_transform_info(png_structp png_ptr, png_voidp
+   user_transform_ptr, int user_transform_depth, int user_transform_channels)
+{
+   png_debug(1, "in png_set_user_transform_info\n");
+   if(png_ptr == NULL) return;
+#if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
+   png_ptr->user_transform_ptr = user_transform_ptr;
+   png_ptr->user_transform_depth = (png_byte)user_transform_depth;
+   png_ptr->user_transform_channels = (png_byte)user_transform_channels;
+#else
+   if(user_transform_ptr || user_transform_depth || user_transform_channels)
+      png_warning(png_ptr,
+        "This version of libpng does not support user transform info");
+#endif
+}
+#endif
+
+/* This function returns a pointer to the user_transform_ptr associated with
+ * the user transform functions.  The application should free any memory
+ * associated with this pointer before png_write_destroy and png_read_destroy
+ * are called.
+ */
+png_voidp PNGAPI
+png_get_user_transform_ptr(png_structp png_ptr)
+{
+#if defined(PNG_USER_TRANSFORM_PTR_SUPPORTED)
+   if (png_ptr == NULL) return (NULL);
+   return ((png_voidp)png_ptr->user_transform_ptr);
+#else
+   return (NULL);
+#endif
+}
+#endif /* PNG_READ_SUPPORTED || PNG_WRITE_SUPPORTED */
diff --git a/distrib/libpng-1.2.19/pngvcrd.c b/distrib/libpng-1.2.19/pngvcrd.c
new file mode 100644
index 0000000..34d42c9
--- /dev/null
+++ b/distrib/libpng-1.2.19/pngvcrd.c
@@ -0,0 +1,3922 @@
+
+/* pngvcrd.c - mixed C/assembler version of utilities to read a PNG file
+ *
+ * For Intel x86 CPU and Microsoft Visual C++ compiler
+ *
+ * Last changed in libpng 1.2.19 August 18, 2007
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1998-2007 Glenn Randers-Pehrson
+ * Copyright (c) 1998, Intel Corporation
+ *
+ * Contributed by Nirav Chhatrapati, Intel Corporation, 1998
+ * Interface to libpng contributed by Gilles Vollant, 1999
+ *
+ *
+ * In png_do_read_interlace() in libpng versions 1.0.3a through 1.0.4d,
+ * a sign error in the post-MMX cleanup code for each pixel_depth resulted
+ * in bad pixels at the beginning of some rows of some images, and also
+ * (due to out-of-range memory reads and writes) caused heap corruption
+ * when compiled with MSVC 6.0.  The error was fixed in version 1.0.4e.
+ *
+ * [png_read_filter_row_mmx_avg() bpp == 2 bugfix, GRR 20000916]
+ *
+ * [runtime MMX configuration, GRR 20010102]
+ *
+ * [Copy 6 bytes per pixel, not 4, and use stride of 6, not 4, in the
+ *  second loop of interlace processing of 48-bit pixels, GR-P 20070717]
+ *
+ * [move instances of uAll union into local, except for two constant
+ * instances, GR-P 20070805]
+ */
+
+#define PNG_INTERNAL
+#include "png.h"
+
+#if defined(PNG_MMX_CODE_SUPPORTED) && defined(PNG_USE_PNGVCRD)
+
+
+static int mmx_supported=2;
+
+int PNGAPI
+png_mmx_support(void)
+{
+  int mmx_supported_local = 0;
+  _asm {
+    push ebx          //CPUID will trash these
+    push ecx
+    push edx
+
+    pushfd            //Save Eflag to stack
+    pop eax           //Get Eflag from stack into eax
+    mov ecx, eax      //Make another copy of Eflag in ecx
+    xor eax, 0x200000 //Toggle ID bit in Eflag [i.e. bit(21)]
+    push eax          //Save modified Eflag back to stack
+
+    popfd             //Restored modified value back to Eflag reg
+    pushfd            //Save Eflag to stack
+    pop eax           //Get Eflag from stack
+    push ecx          // save original Eflag to stack
+    popfd             // restore original Eflag
+    xor eax, ecx      //Compare the new Eflag with the original Eflag
+    jz NOT_SUPPORTED  //If the same, CPUID instruction is not supported,
+                      //skip following instructions and jump to
+                      //NOT_SUPPORTED label
+
+    xor eax, eax      //Set eax to zero
+
+    _asm _emit 0x0f   //CPUID instruction  (two bytes opcode)
+    _asm _emit 0xa2
+
+    cmp eax, 1        //make sure eax return non-zero value
+    jl NOT_SUPPORTED  //If eax is zero, mmx not supported
+
+    xor eax, eax      //set eax to zero
+    inc eax           //Now increment eax to 1.  This instruction is
+                      //faster than the instruction "mov eax, 1"
+
+    _asm _emit 0x0f   //CPUID instruction
+    _asm _emit 0xa2
+
+    and edx, 0x00800000  //mask out all bits but mmx bit(24)
+    cmp edx, 0        // 0 = mmx not supported
+    jz  NOT_SUPPORTED // non-zero = Yes, mmx IS supported
+
+    mov  mmx_supported_local, 1  //set return value to 1
+
+NOT_SUPPORTED:
+    mov  eax, mmx_supported_local  //move return value to eax
+    pop edx          //CPUID trashed these
+    pop ecx
+    pop ebx
+  }
+
+  //mmx_supported_local=0; // test code for force don't support MMX
+  //printf("MMX : %u (1=MMX supported)\n",mmx_supported_local);
+
+  mmx_supported = mmx_supported_local;
+  return mmx_supported_local;
+}
+
+/* Combines the row recently read in with the previous row.
+   This routine takes care of alpha and transparency if requested.
+   This routine also handles the two methods of progressive display
+   of interlaced images, depending on the mask value.
+   The mask value describes which pixels are to be combined with
+   the row.  The pattern always repeats every 8 pixels, so just 8
+   bits are needed.  A one indicates the pixel is to be combined; a
+   zero indicates the pixel is to be skipped.  This is in addition
+   to any alpha or transparency value associated with the pixel.  If
+   you want all pixels to be combined, pass 0xff (255) in mask.  */
+
+/* Use this routine for x86 platform - uses faster MMX routine if machine
+   supports MMX */
+
+void /* PRIVATE */
+png_combine_row(png_structp png_ptr, png_bytep row, int mask)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_CONST int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+#endif
+
+   png_debug(1,"in png_combine_row_asm\n");
+
+   if (mmx_supported == 2) {
+#if !defined(PNG_1_0_X)
+       /* this should have happened in png_init_mmx_flags() already */
+       png_warning(png_ptr, "asm_flags may not have been initialized");
+#endif
+       png_mmx_support();
+   }
+
+   if (mask == 0xff)
+   {
+      png_memcpy(row, png_ptr->row_buf + 1,
+       (png_size_t)PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
+       png_ptr->width));
+   }
+   /* GRR:  add "else if (mask == 0)" case?
+    *       or does png_combine_row() not even get called in that case? */
+   else
+   {
+      switch (png_ptr->row_info.pixel_depth)
+      {
+         case 24:
+         {
+            png_bytep srcptr;
+            png_bytep dstptr;
+            png_uint_32 len;
+            int unmask, diff;
+
+            __int64 mask2=0x0101010202020404,  //24bpp
+                    mask1=0x0408080810101020,
+                    mask0=0x2020404040808080;
+
+            srcptr = png_ptr->row_buf + 1;
+            dstptr = row;
+
+            unmask = ~mask;
+            len     = (png_ptr->width)&~7;
+            diff = (png_ptr->width)&7;
+
+#if !defined(PNG_1_0_X)
+            if ((png_ptr->asm_flags & PNG_ASM_FLAG_MMX_READ_COMBINE_ROW)
+                /* && mmx_supported */ )
+#else
+            if (mmx_supported)
+#endif
+            {
+               _asm
+               {
+                  movd       mm7, unmask       //load bit pattern
+                  psubb      mm6,mm6           //zero mm6
+                  punpcklbw  mm7,mm7
+                  punpcklwd  mm7,mm7
+                  punpckldq  mm7,mm7           //fill register with 8 masks
+
+                  movq       mm0,mask0
+                  movq       mm1,mask1
+                  movq       mm2,mask2
+
+                  pand       mm0,mm7
+                  pand       mm1,mm7
+                  pand       mm2,mm7
+
+                  pcmpeqb    mm0,mm6
+                  pcmpeqb    mm1,mm6
+                  pcmpeqb    mm2,mm6
+
+                  mov        ecx,len           //load length of line
+                  mov        esi,srcptr        //load source
+                  mov        ebx,dstptr        //load dest
+                  cmp        ecx,0
+                  jz         mainloop24end
+
+mainloop24:
+                  movq       mm4,[esi]
+                  pand       mm4,mm0
+                  movq       mm6,mm0
+                  movq       mm7,[ebx]
+                  pandn      mm6,mm7
+                  por        mm4,mm6
+                  movq       [ebx],mm4
+
+
+                  movq       mm5,[esi+8]
+                  pand       mm5,mm1
+                  movq       mm7,mm1
+                  movq       mm6,[ebx+8]
+                  pandn      mm7,mm6
+                  por        mm5,mm7
+                  movq       [ebx+8],mm5
+
+                  movq       mm6,[esi+16]
+                  pand       mm6,mm2
+                  movq       mm4,mm2
+                  movq       mm7,[ebx+16]
+                  pandn      mm4,mm7
+                  por        mm6,mm4
+                  movq       [ebx+16],mm6
+
+                  add        esi,24            //inc by 24 bytes processed
+                  add        ebx,24
+                  sub        ecx,8             //dec by 8 pixels processed
+
+                  ja         mainloop24
+
+mainloop24end:
+                  mov        ecx,diff
+                  cmp        ecx,0
+                  jz         end24
+
+                  mov        edx,mask
+                  sal        edx,24            //make low byte the high byte
+secondloop24:
+                  sal        edx,1             //move high bit to CF
+                  jnc        skip24            //if CF = 0
+                  mov        ax,[esi]
+                  mov        [ebx],ax
+                  xor        eax,eax
+                  mov        al,[esi+2]
+                  mov        [ebx+2],al
+skip24:
+                  add        esi,3
+                  add        ebx,3
+
+                  dec        ecx
+                  jnz        secondloop24
+
+end24:
+                  emms
+               }
+            }
+            else /* mmx not supported - use modified C routine */
+            {
+               register unsigned int incr1, initial_val, final_val;
+               png_size_t pixel_bytes;
+               png_uint_32 i;
+               register int disp = png_pass_inc[png_ptr->pass];
+               int offset_table[7] = {0, 4, 0, 2, 0, 1, 0};
+
+               pixel_bytes = (png_ptr->row_info.pixel_depth >> 3);
+               srcptr = png_ptr->row_buf + 1 + offset_table[png_ptr->pass]*
+                  pixel_bytes;
+               dstptr = row + offset_table[png_ptr->pass]*pixel_bytes;
+               initial_val = offset_table[png_ptr->pass]*pixel_bytes;
+               final_val = png_ptr->width*pixel_bytes;
+               incr1 = (disp)*pixel_bytes;
+               for (i = initial_val; i < final_val; i += incr1)
+               {
+                  png_memcpy(dstptr, srcptr, pixel_bytes);
+                  srcptr += incr1;
+                  dstptr += incr1;
+               }
+            } /* end of else */
+
+            break;
+         }       // end 24 bpp
+
+         case 32:
+         {
+            png_bytep srcptr;
+            png_bytep dstptr;
+            png_uint_32 len;
+            int unmask, diff;
+
+            __int64 mask3=0x0101010102020202,  //32bpp
+                    mask2=0x0404040408080808,
+                    mask1=0x1010101020202020,
+                    mask0=0x4040404080808080;
+
+            srcptr = png_ptr->row_buf + 1;
+            dstptr = row;
+
+            unmask = ~mask;
+            len     = (png_ptr->width)&~7;
+            diff = (png_ptr->width)&7;
+
+#if !defined(PNG_1_0_X)
+            if ((png_ptr->asm_flags & PNG_ASM_FLAG_MMX_READ_COMBINE_ROW)
+                /* && mmx_supported */ )
+#else
+            if (mmx_supported)
+#endif
+            {
+               _asm
+               {
+                  movd       mm7, unmask       //load bit pattern
+                  psubb      mm6,mm6           //zero mm6
+                  punpcklbw  mm7,mm7
+                  punpcklwd  mm7,mm7
+                  punpckldq  mm7,mm7           //fill register with 8 masks
+
+                  movq       mm0,mask0
+                  movq       mm1,mask1
+                  movq       mm2,mask2
+                  movq       mm3,mask3
+
+                  pand       mm0,mm7
+                  pand       mm1,mm7
+                  pand       mm2,mm7
+                  pand       mm3,mm7
+
+                  pcmpeqb    mm0,mm6
+                  pcmpeqb    mm1,mm6
+                  pcmpeqb    mm2,mm6
+                  pcmpeqb    mm3,mm6
+
+                  mov        ecx,len           //load length of line
+                  mov        esi,srcptr        //load source
+                  mov        ebx,dstptr        //load dest
+
+                  cmp        ecx,0             //lcr
+                  jz         mainloop32end
+
+mainloop32:
+                  movq       mm4,[esi]
+                  pand       mm4,mm0
+                  movq       mm6,mm0
+                  movq       mm7,[ebx]
+                  pandn      mm6,mm7
+                  por        mm4,mm6
+                  movq       [ebx],mm4
+
+                  movq       mm5,[esi+8]
+                  pand       mm5,mm1
+                  movq       mm7,mm1
+                  movq       mm6,[ebx+8]
+                  pandn      mm7,mm6
+                  por        mm5,mm7
+                  movq       [ebx+8],mm5
+
+                  movq       mm6,[esi+16]
+                  pand       mm6,mm2
+                  movq       mm4,mm2
+                  movq       mm7,[ebx+16]
+                  pandn      mm4,mm7
+                  por        mm6,mm4
+                  movq       [ebx+16],mm6
+
+                  movq       mm7,[esi+24]
+                  pand       mm7,mm3
+                  movq       mm5,mm3
+                  movq       mm4,[ebx+24]
+                  pandn      mm5,mm4
+                  por        mm7,mm5
+                  movq       [ebx+24],mm7
+
+                  add        esi,32            //inc by 32 bytes processed
+                  add        ebx,32
+                  sub        ecx,8             //dec by 8 pixels processed
+
+                  ja         mainloop32
+
+mainloop32end:
+                  mov        ecx,diff
+                  cmp        ecx,0
+                  jz         end32
+
+                  mov        edx,mask
+                  sal        edx,24            //make low byte the high byte
+secondloop32:
+                  sal        edx,1             //move high bit to CF
+                  jnc        skip32            //if CF = 0
+                  mov        eax,[esi]
+                  mov        [ebx],eax
+skip32:
+                  add        esi,4
+                  add        ebx,4
+
+                  dec        ecx
+                  jnz        secondloop32
+
+end32:
+                  emms
+               }
+            }
+            else /* mmx _not supported - Use modified C routine */
+            {
+               register unsigned int incr1, initial_val, final_val;
+               png_size_t pixel_bytes;
+               png_uint_32 i;
+               register int disp = png_pass_inc[png_ptr->pass];
+               int offset_table[7] = {0, 4, 0, 2, 0, 1, 0};
+
+               pixel_bytes = (png_ptr->row_info.pixel_depth >> 3);
+               srcptr = png_ptr->row_buf + 1 + offset_table[png_ptr->pass]*
+                  pixel_bytes;
+               dstptr = row + offset_table[png_ptr->pass]*pixel_bytes;
+               initial_val = offset_table[png_ptr->pass]*pixel_bytes;
+               final_val = png_ptr->width*pixel_bytes;
+               incr1 = (disp)*pixel_bytes;
+               for (i = initial_val; i < final_val; i += incr1)
+               {
+                  png_memcpy(dstptr, srcptr, pixel_bytes);
+                  srcptr += incr1;
+                  dstptr += incr1;
+               }
+            } /* end of else */
+
+            break;
+         }       // end 32 bpp
+
+         case 8:
+         {
+            png_bytep srcptr;
+            png_bytep dstptr;
+            png_uint_32 len;
+            int m;
+            int diff, unmask;
+
+            __int64 mask0=0x0102040810204080;
+
+#if !defined(PNG_1_0_X)
+            if ((png_ptr->asm_flags & PNG_ASM_FLAG_MMX_READ_COMBINE_ROW)
+                /* && mmx_supported */ )
+#else
+            if (mmx_supported)
+#endif
+            {
+               srcptr = png_ptr->row_buf + 1;
+               dstptr = row;
+               m = 0x80;
+               unmask = ~mask;
+               len  = png_ptr->width &~7;  //reduce to multiple of 8
+               diff = png_ptr->width & 7;  //amount lost
+
+               _asm
+               {
+                  movd       mm7, unmask   //load bit pattern
+                  psubb      mm6,mm6       //zero mm6
+                  punpcklbw  mm7,mm7
+                  punpcklwd  mm7,mm7
+                  punpckldq  mm7,mm7       //fill register with 8 masks
+
+                  movq       mm0,mask0
+
+                  pand       mm0,mm7       //nonzero if keep byte
+                  pcmpeqb    mm0,mm6       //zeros->1s, v versa
+
+                  mov        ecx,len       //load length of line (pixels)
+                  mov        esi,srcptr    //load source
+                  mov        ebx,dstptr    //load dest
+                  cmp        ecx,0         //lcr
+                  je         mainloop8end
+
+mainloop8:
+                  movq       mm4,[esi]
+                  pand       mm4,mm0
+                  movq       mm6,mm0
+                  pandn      mm6,[ebx]
+                  por        mm4,mm6
+                  movq       [ebx],mm4
+
+                  add        esi,8         //inc by 8 bytes processed
+                  add        ebx,8
+                  sub        ecx,8         //dec by 8 pixels processed
+
+                  ja         mainloop8
+mainloop8end:
+
+                  mov        ecx,diff
+                  cmp        ecx,0
+                  jz         end8
+
+                  mov        edx,mask
+                  sal        edx,24        //make low byte the high byte
+
+secondloop8:
+                  sal        edx,1         //move high bit to CF
+                  jnc        skip8         //if CF = 0
+                  mov        al,[esi]
+                  mov        [ebx],al
+skip8:
+                  inc        esi
+                  inc        ebx
+
+                  dec        ecx
+                  jnz        secondloop8
+end8:
+                  emms
+               }
+            }
+            else /* mmx not supported - use modified C routine */
+            {
+               register unsigned int incr1, initial_val, final_val;
+               png_size_t pixel_bytes;
+               png_uint_32 i;
+               register int disp = png_pass_inc[png_ptr->pass];
+               int offset_table[7] = {0, 4, 0, 2, 0, 1, 0};
+
+               pixel_bytes = (png_ptr->row_info.pixel_depth >> 3);
+               srcptr = png_ptr->row_buf + 1 + offset_table[png_ptr->pass]*
+                  pixel_bytes;
+               dstptr = row + offset_table[png_ptr->pass]*pixel_bytes;
+               initial_val = offset_table[png_ptr->pass]*pixel_bytes;
+               final_val = png_ptr->width*pixel_bytes;
+               incr1 = (disp)*pixel_bytes;
+               for (i = initial_val; i < final_val; i += incr1)
+               {
+                  png_memcpy(dstptr, srcptr, pixel_bytes);
+                  srcptr += incr1;
+                  dstptr += incr1;
+               }
+            } /* end of else */
+
+            break;
+         }       // end 8 bpp
+
+         case 1:
+         {
+            png_bytep sp;
+            png_bytep dp;
+            int s_inc, s_start, s_end;
+            int m;
+            int shift;
+            png_uint_32 i;
+
+            sp = png_ptr->row_buf + 1;
+            dp = row;
+            m = 0x80;
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+            if (png_ptr->transformations & PNG_PACKSWAP)
+            {
+                s_start = 0;
+                s_end = 7;
+                s_inc = 1;
+            }
+            else
+#endif
+            {
+                s_start = 7;
+                s_end = 0;
+                s_inc = -1;
+            }
+
+            shift = s_start;
+
+            for (i = 0; i < png_ptr->width; i++)
+            {
+               if (m & mask)
+               {
+                  int value;
+
+                  value = (*sp >> shift) & 0x1;
+                  *dp &= (png_byte)((0x7f7f >> (7 - shift)) & 0xff);
+                  *dp |= (png_byte)(value << shift);
+               }
+
+               if (shift == s_end)
+               {
+                  shift = s_start;
+                  sp++;
+                  dp++;
+               }
+               else
+                  shift += s_inc;
+
+               if (m == 1)
+                  m = 0x80;
+               else
+                  m >>= 1;
+            }
+            break;
+         }
+
+         case 2:
+         {
+            png_bytep sp;
+            png_bytep dp;
+            int s_start, s_end, s_inc;
+            int m;
+            int shift;
+            png_uint_32 i;
+            int value;
+
+            sp = png_ptr->row_buf + 1;
+            dp = row;
+            m = 0x80;
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+            if (png_ptr->transformations & PNG_PACKSWAP)
+            {
+               s_start = 0;
+               s_end = 6;
+               s_inc = 2;
+            }
+            else
+#endif
+            {
+               s_start = 6;
+               s_end = 0;
+               s_inc = -2;
+            }
+
+            shift = s_start;
+
+            for (i = 0; i < png_ptr->width; i++)
+            {
+               if (m & mask)
+               {
+                  value = (*sp >> shift) & 0x3;
+                  *dp &= (png_byte)((0x3f3f >> (6 - shift)) & 0xff);
+                  *dp |= (png_byte)(value << shift);
+               }
+
+               if (shift == s_end)
+               {
+                  shift = s_start;
+                  sp++;
+                  dp++;
+               }
+               else
+                  shift += s_inc;
+               if (m == 1)
+                  m = 0x80;
+               else
+                  m >>= 1;
+            }
+            break;
+         }
+
+         case 4:
+         {
+            png_bytep sp;
+            png_bytep dp;
+            int s_start, s_end, s_inc;
+            int m;
+            int shift;
+            png_uint_32 i;
+            int value;
+
+            sp = png_ptr->row_buf + 1;
+            dp = row;
+            m = 0x80;
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+            if (png_ptr->transformations & PNG_PACKSWAP)
+            {
+               s_start = 0;
+               s_end = 4;
+               s_inc = 4;
+            }
+            else
+#endif
+            {
+               s_start = 4;
+               s_end = 0;
+               s_inc = -4;
+            }
+            shift = s_start;
+
+            for (i = 0; i < png_ptr->width; i++)
+            {
+               if (m & mask)
+               {
+                  value = (*sp >> shift) & 0xf;
+                  *dp &= (png_byte)((0xf0f >> (4 - shift)) & 0xff);
+                  *dp |= (png_byte)(value << shift);
+               }
+
+               if (shift == s_end)
+               {
+                  shift = s_start;
+                  sp++;
+                  dp++;
+               }
+               else
+                  shift += s_inc;
+               if (m == 1)
+                  m = 0x80;
+               else
+                  m >>= 1;
+            }
+            break;
+         }
+
+         case 16:
+         {
+            png_bytep srcptr;
+            png_bytep dstptr;
+            png_uint_32 len;
+            int unmask, diff;
+            __int64 mask1=0x0101020204040808,
+                    mask0=0x1010202040408080;
+
+#if !defined(PNG_1_0_X)
+            if ((png_ptr->asm_flags & PNG_ASM_FLAG_MMX_READ_COMBINE_ROW)
+                /* && mmx_supported */ )
+#else
+            if (mmx_supported)
+#endif
+            {
+               srcptr = png_ptr->row_buf + 1;
+               dstptr = row;
+
+               unmask = ~mask;
+               len     = (png_ptr->width)&~7;
+               diff = (png_ptr->width)&7;
+               _asm
+               {
+                  movd       mm7, unmask       //load bit pattern
+                  psubb      mm6,mm6           //zero mm6
+                  punpcklbw  mm7,mm7
+                  punpcklwd  mm7,mm7
+                  punpckldq  mm7,mm7           //fill register with 8 masks
+
+                  movq       mm0,mask0
+                  movq       mm1,mask1
+
+                  pand       mm0,mm7
+                  pand       mm1,mm7
+
+                  pcmpeqb    mm0,mm6
+                  pcmpeqb    mm1,mm6
+
+                  mov        ecx,len           //load length of line
+                  mov        esi,srcptr        //load source
+                  mov        ebx,dstptr        //load dest
+                  cmp        ecx,0             //lcr
+                  jz         mainloop16end
+
+mainloop16:
+                  movq       mm4,[esi]
+                  pand       mm4,mm0
+                  movq       mm6,mm0
+                  movq       mm7,[ebx]
+                  pandn      mm6,mm7
+                  por        mm4,mm6
+                  movq       [ebx],mm4
+
+                  movq       mm5,[esi+8]
+                  pand       mm5,mm1
+                  movq       mm7,mm1
+                  movq       mm6,[ebx+8]
+                  pandn      mm7,mm6
+                  por        mm5,mm7
+                  movq       [ebx+8],mm5
+
+                  add        esi,16            //inc by 16 bytes processed
+                  add        ebx,16
+                  sub        ecx,8             //dec by 8 pixels processed
+
+                  ja         mainloop16
+
+mainloop16end:
+                  mov        ecx,diff
+                  cmp        ecx,0
+                  jz         end16
+
+                  mov        edx,mask
+                  sal        edx,24            //make low byte the high byte
+secondloop16:
+                  sal        edx,1             //move high bit to CF
+                  jnc        skip16            //if CF = 0
+                  mov        ax,[esi]
+                  mov        [ebx],ax
+skip16:
+                  add        esi,2
+                  add        ebx,2
+
+                  dec        ecx
+                  jnz        secondloop16
+end16:
+                  emms
+               }
+            }
+            else /* mmx not supported - use modified C routine */
+            {
+               register unsigned int incr1, initial_val, final_val;
+               png_size_t pixel_bytes;
+               png_uint_32 i;
+               register int disp = png_pass_inc[png_ptr->pass];
+               int offset_table[7] = {0, 4, 0, 2, 0, 1, 0};
+
+               pixel_bytes = (png_ptr->row_info.pixel_depth >> 3);
+               srcptr = png_ptr->row_buf + 1 + offset_table[png_ptr->pass]*
+                  pixel_bytes;
+               dstptr = row + offset_table[png_ptr->pass]*pixel_bytes;
+               initial_val = offset_table[png_ptr->pass]*pixel_bytes;
+               final_val = png_ptr->width*pixel_bytes;
+               incr1 = (disp)*pixel_bytes;
+               for (i = initial_val; i < final_val; i += incr1)
+               {
+                  png_memcpy(dstptr, srcptr, pixel_bytes);
+                  srcptr += incr1;
+                  dstptr += incr1;
+               }
+            } /* end of else */
+
+            break;
+         }       // end 16 bpp
+
+         case 48:
+         {
+            png_bytep srcptr;
+            png_bytep dstptr;
+            png_uint_32 len;
+            int unmask, diff;
+
+            __int64 mask5=0x0101010101010202,
+                    mask4=0x0202020204040404,
+                    mask3=0x0404080808080808,
+                    mask2=0x1010101010102020,
+                    mask1=0x2020202040404040,
+                    mask0=0x4040808080808080;
+
+#if !defined(PNG_1_0_X)
+            if ((png_ptr->asm_flags & PNG_ASM_FLAG_MMX_READ_COMBINE_ROW)
+                /* && mmx_supported */ )
+#else
+            if (mmx_supported)
+#endif
+            {
+               srcptr = png_ptr->row_buf + 1;
+               dstptr = row;
+
+               unmask = ~mask;
+               len     = (png_ptr->width)&~7;
+               diff = (png_ptr->width)&7;
+               _asm
+               {
+                  movd       mm7, unmask       //load bit pattern
+                  psubb      mm6,mm6           //zero mm6
+                  punpcklbw  mm7,mm7
+                  punpcklwd  mm7,mm7
+                  punpckldq  mm7,mm7           //fill register with 8 masks
+
+                  movq       mm0,mask0
+                  movq       mm1,mask1
+                  movq       mm2,mask2
+                  movq       mm3,mask3
+                  movq       mm4,mask4
+                  movq       mm5,mask5
+
+                  pand       mm0,mm7
+                  pand       mm1,mm7
+                  pand       mm2,mm7
+                  pand       mm3,mm7
+                  pand       mm4,mm7
+                  pand       mm5,mm7
+
+                  pcmpeqb    mm0,mm6
+                  pcmpeqb    mm1,mm6
+                  pcmpeqb    mm2,mm6
+                  pcmpeqb    mm3,mm6
+                  pcmpeqb    mm4,mm6
+                  pcmpeqb    mm5,mm6
+
+                  mov        ecx,len           //load length of line
+                  mov        esi,srcptr        //load source
+                  mov        ebx,dstptr        //load dest
+
+                  cmp        ecx,0
+                  jz         mainloop48end
+
+mainloop48:
+                  movq       mm7,[esi]
+                  pand       mm7,mm0
+                  movq       mm6,mm0
+                  pandn      mm6,[ebx]
+                  por        mm7,mm6
+                  movq       [ebx],mm7
+
+                  movq       mm6,[esi+8]
+                  pand       mm6,mm1
+                  movq       mm7,mm1
+                  pandn      mm7,[ebx+8]
+                  por        mm6,mm7
+                  movq       [ebx+8],mm6
+
+                  movq       mm6,[esi+16]
+                  pand       mm6,mm2
+                  movq       mm7,mm2
+                  pandn      mm7,[ebx+16]
+                  por        mm6,mm7
+                  movq       [ebx+16],mm6
+
+                  movq       mm7,[esi+24]
+                  pand       mm7,mm3
+                  movq       mm6,mm3
+                  pandn      mm6,[ebx+24]
+                  por        mm7,mm6
+                  movq       [ebx+24],mm7
+
+                  movq       mm6,[esi+32]
+                  pand       mm6,mm4
+                  movq       mm7,mm4
+                  pandn      mm7,[ebx+32]
+                  por        mm6,mm7
+                  movq       [ebx+32],mm6
+
+                  movq       mm7,[esi+40]
+                  pand       mm7,mm5
+                  movq       mm6,mm5
+                  pandn      mm6,[ebx+40]
+                  por        mm7,mm6
+                  movq       [ebx+40],mm7
+
+                  add        esi,48            //inc by 32 bytes processed
+                  add        ebx,48
+                  sub        ecx,8             //dec by 8 pixels processed
+
+                  ja         mainloop48
+mainloop48end:
+
+                  mov        ecx,diff
+                  cmp        ecx,0
+                  jz         end48
+
+                  mov        edx,mask
+                  sal        edx,24            //make low byte the high byte
+
+secondloop48:
+                  sal        edx,1             //move high bit to CF
+                  jnc        skip48            //if CF = 0
+                  mov        eax,[esi]
+                  mov        [ebx],eax
+                  mov        ax,[esi+4]       // These 2 lines added 20070717
+                  mov        [ebx+4],ax       // Glenn R-P
+skip48:
+                  add        esi,6            // Changed 4 to 6 on these 2
+                  add        ebx,6            // lines.  Glenn R-P 20070717
+
+                  dec        ecx
+                  jnz        secondloop48
+
+end48:
+                  emms
+               }
+            }
+            else /* mmx _not supported - Use modified C routine */
+            {
+               register unsigned int incr1, initial_val, final_val;
+               png_size_t pixel_bytes;
+               png_uint_32 i;
+               register int disp = png_pass_inc[png_ptr->pass];
+               int offset_table[7] = {0, 4, 0, 2, 0, 1, 0};
+
+               pixel_bytes = (png_ptr->row_info.pixel_depth >> 3);
+               srcptr = png_ptr->row_buf + 1 + offset_table[png_ptr->pass]*
+                  pixel_bytes;
+               dstptr = row + offset_table[png_ptr->pass]*pixel_bytes;
+               initial_val = offset_table[png_ptr->pass]*pixel_bytes;
+               final_val = png_ptr->width*pixel_bytes;
+               incr1 = (disp)*pixel_bytes;
+               for (i = initial_val; i < final_val; i += incr1)
+               {
+                  png_memcpy(dstptr, srcptr, pixel_bytes);
+                  srcptr += incr1;
+                  dstptr += incr1;
+               }
+            } /* end of else */
+
+            break;
+         }       // end 48 bpp
+
+         default:
+         {
+            png_bytep sptr;
+            png_bytep dp;
+            png_size_t pixel_bytes;
+            int offset_table[7] = {0, 4, 0, 2, 0, 1, 0};
+            unsigned int i;
+            register int disp = png_pass_inc[png_ptr->pass];  // get the offset
+            register unsigned int incr1, initial_val, final_val;
+
+            pixel_bytes = (png_ptr->row_info.pixel_depth >> 3);
+            sptr = png_ptr->row_buf + 1 + offset_table[png_ptr->pass]*
+               pixel_bytes;
+            dp = row + offset_table[png_ptr->pass]*pixel_bytes;
+            initial_val = offset_table[png_ptr->pass]*pixel_bytes;
+            final_val = png_ptr->width*pixel_bytes;
+            incr1 = (disp)*pixel_bytes;
+            for (i = initial_val; i < final_val; i += incr1)
+            {
+               png_memcpy(dp, sptr, pixel_bytes);
+               sptr += incr1;
+               dp += incr1;
+            }
+            break;
+         }
+      } /* end switch (png_ptr->row_info.pixel_depth) */
+   } /* end if (non-trivial mask) */
+
+} /* end png_combine_row() */
+
+
+#if defined(PNG_READ_INTERLACING_SUPPORTED)
+
+void /* PRIVATE */
+png_do_read_interlace(png_structp png_ptr)
+{
+   png_row_infop row_info = &(png_ptr->row_info);
+   png_bytep row = png_ptr->row_buf + 1;
+   int pass = png_ptr->pass;
+   png_uint_32 transformations = png_ptr->transformations;
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_CONST int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+#endif
+
+   png_debug(1,"in png_do_read_interlace\n");
+
+   if (mmx_supported == 2) {
+#if !defined(PNG_1_0_X)
+       /* this should have happened in png_init_mmx_flags() already */
+       png_warning(png_ptr, "asm_flags may not have been initialized");
+#endif
+       png_mmx_support();
+   }
+
+   if (row != NULL && row_info != NULL)
+   {
+      png_uint_32 final_width;
+
+      final_width = row_info->width * png_pass_inc[pass];
+
+      switch (row_info->pixel_depth)
+      {
+         case 1:
+         {
+            png_bytep sp, dp;
+            int sshift, dshift;
+            int s_start, s_end, s_inc;
+            png_byte v;
+            png_uint_32 i;
+            int j;
+
+            sp = row + (png_size_t)((row_info->width - 1) >> 3);
+            dp = row + (png_size_t)((final_width - 1) >> 3);
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+            if (transformations & PNG_PACKSWAP)
+            {
+               sshift = (int)((row_info->width + 7) & 7);
+               dshift = (int)((final_width + 7) & 7);
+               s_start = 7;
+               s_end = 0;
+               s_inc = -1;
+            }
+            else
+#endif
+            {
+               sshift = 7 - (int)((row_info->width + 7) & 7);
+               dshift = 7 - (int)((final_width + 7) & 7);
+               s_start = 0;
+               s_end = 7;
+               s_inc = 1;
+            }
+
+            for (i = row_info->width; i; i--)
+            {
+               v = (png_byte)((*sp >> sshift) & 0x1);
+               for (j = 0; j < png_pass_inc[pass]; j++)
+               {
+                  *dp &= (png_byte)((0x7f7f >> (7 - dshift)) & 0xff);
+                  *dp |= (png_byte)(v << dshift);
+                  if (dshift == s_end)
+                  {
+                     dshift = s_start;
+                     dp--;
+                  }
+                  else
+                     dshift += s_inc;
+               }
+               if (sshift == s_end)
+               {
+                  sshift = s_start;
+                  sp--;
+               }
+               else
+                  sshift += s_inc;
+            }
+            break;
+         }
+
+         case 2:
+         {
+            png_bytep sp, dp;
+            int sshift, dshift;
+            int s_start, s_end, s_inc;
+            png_uint_32 i;
+
+            sp = row + (png_size_t)((row_info->width - 1) >> 2);
+            dp = row + (png_size_t)((final_width - 1) >> 2);
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+            if (transformations & PNG_PACKSWAP)
+            {
+               sshift = (png_size_t)(((row_info->width + 3) & 3) << 1);
+               dshift = (png_size_t)(((final_width + 3) & 3) << 1);
+               s_start = 6;
+               s_end = 0;
+               s_inc = -2;
+            }
+            else
+#endif
+            {
+               sshift = (png_size_t)((3 - ((row_info->width + 3) & 3)) << 1);
+               dshift = (png_size_t)((3 - ((final_width + 3) & 3)) << 1);
+               s_start = 0;
+               s_end = 6;
+               s_inc = 2;
+            }
+
+            for (i = row_info->width; i; i--)
+            {
+               png_byte v;
+               int j;
+
+               v = (png_byte)((*sp >> sshift) & 0x3);
+               for (j = 0; j < png_pass_inc[pass]; j++)
+               {
+                  *dp &= (png_byte)((0x3f3f >> (6 - dshift)) & 0xff);
+                  *dp |= (png_byte)(v << dshift);
+                  if (dshift == s_end)
+                  {
+                     dshift = s_start;
+                     dp--;
+                  }
+                  else
+                     dshift += s_inc;
+               }
+               if (sshift == s_end)
+               {
+                  sshift = s_start;
+                  sp--;
+               }
+               else
+                  sshift += s_inc;
+            }
+            break;
+         }
+
+         case 4:
+         {
+            png_bytep sp, dp;
+            int sshift, dshift;
+            int s_start, s_end, s_inc;
+            png_uint_32 i;
+
+            sp = row + (png_size_t)((row_info->width - 1) >> 1);
+            dp = row + (png_size_t)((final_width - 1) >> 1);
+#if defined(PNG_READ_PACKSWAP_SUPPORTED)
+            if (transformations & PNG_PACKSWAP)
+            {
+               sshift = (png_size_t)(((row_info->width + 1) & 1) << 2);
+               dshift = (png_size_t)(((final_width + 1) & 1) << 2);
+               s_start = 4;
+               s_end = 0;
+               s_inc = -4;
+            }
+            else
+#endif
+            {
+               sshift = (png_size_t)((1 - ((row_info->width + 1) & 1)) << 2);
+               dshift = (png_size_t)((1 - ((final_width + 1) & 1)) << 2);
+               s_start = 0;
+               s_end = 4;
+               s_inc = 4;
+            }
+
+            for (i = row_info->width; i; i--)
+            {
+               png_byte v;
+               int j;
+
+               v = (png_byte)((*sp >> sshift) & 0xf);
+               for (j = 0; j < png_pass_inc[pass]; j++)
+               {
+                  *dp &= (png_byte)((0xf0f >> (4 - dshift)) & 0xff);
+                  *dp |= (png_byte)(v << dshift);
+                  if (dshift == s_end)
+                  {
+                     dshift = s_start;
+                     dp--;
+                  }
+                  else
+                     dshift += s_inc;
+               }
+               if (sshift == s_end)
+               {
+                  sshift = s_start;
+                  sp--;
+               }
+               else
+                  sshift += s_inc;
+            }
+            break;
+         }
+
+         default:         // This is the place where the routine is modified
+         {
+            __int64 const4 = 0x0000000000FFFFFF;
+            // __int64 const5 = 0x000000FFFFFF0000;  // unused...
+            __int64 const6 = 0x00000000000000FF;
+            png_bytep sptr, dp;
+            png_uint_32 i;
+            png_size_t pixel_bytes;
+            int width = row_info->width;
+
+            pixel_bytes = (row_info->pixel_depth >> 3);
+
+            sptr = row + (width - 1) * pixel_bytes;
+            dp = row + (final_width - 1) * pixel_bytes;
+            // New code by Nirav Chhatrapati - Intel Corporation
+            // sign fix by GRR
+            // NOTE:  there is NO MMX code for 48-bit and 64-bit images
+
+            // use MMX routine if machine supports it
+#if !defined(PNG_1_0_X)
+            if ((png_ptr->asm_flags & PNG_ASM_FLAG_MMX_READ_INTERLACE)
+                /* && mmx_supported */ )
+#else
+            if (mmx_supported)
+#endif
+            {
+               if (pixel_bytes == 3)
+               {
+                  if (((pass == 4) || (pass == 5)) && width)
+                  {
+                     int width_mmx = ((width >> 1) << 1) - 8;
+                     if (width_mmx < 0)
+                         width_mmx = 0;
+                     width -= width_mmx;        // 8 or 9 pix, 24 or 27 bytes
+                     if (width_mmx)
+                     {
+                        _asm
+                        {
+                           mov esi, sptr
+                           mov edi, dp
+                           mov ecx, width_mmx
+                           sub esi, 3
+                           sub edi, 9
+loop_pass4:
+                           movq mm0, [esi]     ; X X v2 v1 v0 v5 v4 v3
+                           movq mm7, mm0       ; X X v2 v1 v0 v5 v4 v3
+                           movq mm6, mm0       ; X X v2 v1 v0 v5 v4 v3
+                           psllq mm0, 24       ; v1 v0 v5 v4 v3 0 0 0
+                           pand mm7, const4    ; 0 0 0 0 0 v5 v4 v3
+                           psrlq mm6, 24       ; 0 0 0 X X v2 v1 v0
+                           por mm0, mm7        ; v1 v0 v5 v4 v3 v5 v4 v3
+                           movq mm5, mm6       ; 0 0 0 X X v2 v1 v0
+                           psllq mm6, 8        ; 0 0 X X v2 v1 v0 0
+                           movq [edi], mm0     ; move quad to memory
+                           psrlq mm5, 16       ; 0 0 0 0 0 X X v2
+                           pand mm5, const6    ; 0 0 0 0 0 0 0 v2
+                           por mm6, mm5        ; 0 0 X X v2 v1 v0 v2
+                           movd [edi+8], mm6   ; move double to memory
+                           sub esi, 6
+                           sub edi, 12
+                           sub ecx, 2
+                           jnz loop_pass4
+                           EMMS
+                        }
+                     }
+
+                     sptr -= width_mmx*3;
+                     dp -= width_mmx*6;
+                     for (i = width; i; i--)
+                     {
+                        png_byte v[8];
+                        int j;
+
+                        png_memcpy(v, sptr, 3);
+                        for (j = 0; j < png_pass_inc[pass]; j++)
+                        {
+                           png_memcpy(dp, v, 3);
+                           dp -= 3;
+                        }
+                        sptr -= 3;
+                     }
+                  }
+                  else if (((pass == 2) || (pass == 3)) && width)
+                  {
+                     _asm
+                     {
+                        mov esi, sptr
+                        mov edi, dp
+                        mov ecx, width
+                        sub edi, 9   // (png_pass_inc[pass] - 1)*pixel_bytes
+loop_pass2:
+                        movd mm0, [esi]     ; X X X X X v2 v1 v0
+                        pand mm0, const4    ; 0 0 0 0 0 v2 v1 v0
+                        movq mm1, mm0       ; 0 0 0 0 0 v2 v1 v0
+                        psllq mm0, 16       ; 0 0 0 v2 v1 v0 0 0
+                        movq mm2, mm0       ; 0 0 0 v2 v1 v0 0 0
+                        psllq mm0, 24       ; v2 v1 v0 0 0 0 0 0
+                        psrlq mm1, 8        ; 0 0 0 0 0 0 v2 v1
+                        por mm0, mm2        ; v2 v1 v0 v2 v1 v0 0 0
+                        por mm0, mm1        ; v2 v1 v0 v2 v1 v0 v2 v1
+                        movq [edi+4], mm0   ; move to memory
+                        psrlq mm0, 16       ; 0 0 v2 v1 v0 v2 v1 v0
+                        movd [edi], mm0     ; move to memory
+                        sub esi, 3
+                        sub edi, 12
+                        dec ecx
+                        jnz loop_pass2
+                        EMMS
+                     }
+                  }
+                  else if (width) /* && ((pass == 0) || (pass == 1))) */
+                  {
+                     _asm
+                     {
+                        mov esi, sptr
+                        mov edi, dp
+                        mov ecx, width
+                        sub edi, 21   // (png_pass_inc[pass] - 1)*pixel_bytes
+loop_pass0:
+                        movd mm0, [esi]     ; X X X X X v2 v1 v0
+                        pand mm0, const4    ; 0 0 0 0 0 v2 v1 v0
+                        movq mm1, mm0       ; 0 0 0 0 0 v2 v1 v0
+                        psllq mm0, 16       ; 0 0 0 v2 v1 v0 0 0
+                        movq mm2, mm0       ; 0 0 0 v2 v1 v0 0 0
+                        psllq mm0, 24       ; v2 v1 v0 0 0 0 0 0
+                        psrlq mm1, 8        ; 0 0 0 0 0 0 v2 v1
+                        por mm0, mm2        ; v2 v1 v0 v2 v1 v0 0 0
+                        por mm0, mm1        ; v2 v1 v0 v2 v1 v0 v2 v1
+                        movq mm3, mm0       ; v2 v1 v0 v2 v1 v0 v2 v1
+                        psllq mm0, 16       ; v0 v2 v1 v0 v2 v1 0 0
+                        movq mm4, mm3       ; v2 v1 v0 v2 v1 v0 v2 v1
+                        punpckhdq mm3, mm0  ; v0 v2 v1 v0 v2 v1 v0 v2
+                        movq [edi+16] , mm4
+                        psrlq mm0, 32       ; 0 0 0 0 v0 v2 v1 v0
+                        movq [edi+8] , mm3
+                        punpckldq mm0, mm4  ; v1 v0 v2 v1 v0 v2 v1 v0
+                        sub esi, 3
+                        movq [edi], mm0
+                        sub edi, 24
+                        //sub esi, 3
+                        dec ecx
+                        jnz loop_pass0
+                        EMMS
+                     }
+                  }
+               } /* end of pixel_bytes == 3 */
+
+               else if (pixel_bytes == 1)
+               {
+                  if (((pass == 4) || (pass == 5)) && width)
+                  {
+                     int width_mmx = ((width >> 3) << 3);
+                     width -= width_mmx;
+                     if (width_mmx)
+                     {
+                        _asm
+                        {
+                           mov esi, sptr
+                           mov edi, dp
+                           mov ecx, width_mmx
+                           sub edi, 15
+                           sub esi, 7
+loop1_pass4:
+                           movq mm0, [esi]     ; v0 v1 v2 v3 v4 v5 v6 v7
+                           movq mm1, mm0       ; v0 v1 v2 v3 v4 v5 v6 v7
+                           punpcklbw mm0, mm0  ; v4 v4 v5 v5 v6 v6 v7 v7
+                           //movq mm1, mm0     ; v0 v0 v1 v1 v2 v2 v3 v3
+                           punpckhbw mm1, mm1  ;v0 v0 v1 v1 v2 v2 v3 v3
+                           movq [edi+8], mm1   ; move to memory v0 v1 v2 and v3
+                           sub esi, 8
+                           movq [edi], mm0     ; move to memory v4 v5 v6 and v7
+                           //sub esi, 4
+                           sub edi, 16
+                           sub ecx, 8
+                           jnz loop1_pass4
+                           EMMS
+                        }
+                     }
+
+                     sptr -= width_mmx;
+                     dp -= width_mmx*2;
+                     for (i = width; i; i--)
+                     {
+                        int j;
+
+                        for (j = 0; j < png_pass_inc[pass]; j++)
+                        {
+                           *dp-- = *sptr;
+                        }
+                        sptr --;
+                     }
+                  }
+                  else if (((pass == 2) || (pass == 3)) && width)
+                  {
+                     int width_mmx = ((width >> 2) << 2);
+                     width -= width_mmx;
+                     if (width_mmx)
+                     {
+                        _asm
+                        {
+                           mov esi, sptr
+                           mov edi, dp
+                           mov ecx, width_mmx
+                           sub edi, 15
+                           sub esi, 3
+loop1_pass2:
+                           movd mm0, [esi]     ; X X X X v0 v1 v2 v3
+                           punpcklbw mm0, mm0  ; v0 v0 v1 v1 v2 v2 v3 v3
+                           movq mm1, mm0       ; v0 v0 v1 v1 v2 v2 v3 v3
+                           punpcklwd mm0, mm0  ; v2 v2 v2 v2 v3 v3 v3 v3
+                           punpckhwd mm1, mm1  ; v0 v0 v0 v0 v1 v1 v1 v1
+                           movq [edi], mm0     ; move to memory v2 and v3
+                           sub esi, 4
+                           movq [edi+8], mm1   ; move to memory v1     and v0
+                           sub edi, 16
+                           sub ecx, 4
+                           jnz loop1_pass2
+                           EMMS
+                        }
+                     }
+
+                     sptr -= width_mmx;
+                     dp -= width_mmx*4;
+                     for (i = width; i; i--)
+                     {
+                        int j;
+
+                        for (j = 0; j < png_pass_inc[pass]; j++)
+                        {
+                           *dp-- = *sptr;
+                        }
+                        sptr --;
+                     }
+                  }
+                  else if (width) /* && ((pass == 0) || (pass == 1))) */
+                  {
+                     int width_mmx = ((width >> 2) << 2);
+                     width -= width_mmx;
+                     if (width_mmx)
+                     {
+                        _asm
+                        {
+                           mov esi, sptr
+                           mov edi, dp
+                           mov ecx, width_mmx
+                           sub edi, 31
+                           sub esi, 3
+loop1_pass0:
+                           movd mm0, [esi]     ; X X X X v0 v1 v2 v3
+                           movq mm1, mm0       ; X X X X v0 v1 v2 v3
+                           punpcklbw mm0, mm0  ; v0 v0 v1 v1 v2 v2 v3 v3
+                           movq mm2, mm0       ; v0 v0 v1 v1 v2 v2 v3 v3
+                           punpcklwd mm0, mm0  ; v2 v2 v2 v2 v3 v3 v3 v3
+                           movq mm3, mm0       ; v2 v2 v2 v2 v3 v3 v3 v3
+                           punpckldq mm0, mm0  ; v3 v3 v3 v3 v3 v3 v3 v3
+                           punpckhdq mm3, mm3  ; v2 v2 v2 v2 v2 v2 v2 v2
+                           movq [edi], mm0     ; move to memory v3
+                           punpckhwd mm2, mm2  ; v0 v0 v0 v0 v1 v1 v1 v1
+                           movq [edi+8], mm3   ; move to memory v2
+                           movq mm4, mm2       ; v0 v0 v0 v0 v1 v1 v1 v1
+                           punpckldq mm2, mm2  ; v1 v1 v1 v1 v1 v1 v1 v1
+                           punpckhdq mm4, mm4  ; v0 v0 v0 v0 v0 v0 v0 v0
+                           movq [edi+16], mm2  ; move to memory v1
+                           movq [edi+24], mm4  ; move to memory v0
+                           sub esi, 4
+                           sub edi, 32
+                           sub ecx, 4
+                           jnz loop1_pass0
+                           EMMS
+                        }
+                     }
+
+                     sptr -= width_mmx;
+                     dp -= width_mmx*8;
+                     for (i = width; i; i--)
+                     {
+                        int j;
+
+                       /* I simplified this part in version 1.0.4e
+                        * here and in several other instances where
+                        * pixel_bytes == 1  -- GR-P
+                        *
+                        * Original code:
+                        *
+                        * png_byte v[8];
+                        * png_memcpy(v, sptr, pixel_bytes);
+                        * for (j = 0; j < png_pass_inc[pass]; j++)
+                        * {
+                        *    png_memcpy(dp, v, pixel_bytes);
+                        *    dp -= pixel_bytes;
+                        * }
+                        * sptr -= pixel_bytes;
+                        *
+                        * Replacement code is in the next three lines:
+                        */
+
+                        for (j = 0; j < png_pass_inc[pass]; j++)
+                           *dp-- = *sptr;
+                        sptr--;
+                     }
+                  }
+               } /* end of pixel_bytes == 1 */
+
+               else if (pixel_bytes == 2)
+               {
+                  if (((pass == 4) || (pass == 5)) && width)
+                  {
+                     int width_mmx = ((width >> 1) << 1) ;
+                     width -= width_mmx;
+                     if (width_mmx)
+                     {
+                        _asm
+                        {
+                           mov esi, sptr
+                           mov edi, dp
+                           mov ecx, width_mmx
+                           sub esi, 2
+                           sub edi, 6
+loop2_pass4:
+                           movd mm0, [esi]        ; X X X X v1 v0 v3 v2
+                           punpcklwd mm0, mm0     ; v1 v0 v1 v0 v3 v2 v3 v2
+                           sub esi, 4
+                           movq [edi], mm0
+                           sub edi, 8
+                           sub ecx, 2
+                           jnz loop2_pass4
+                           EMMS
+                        }
+                     }
+
+                     sptr -= (width_mmx*2 - 2);            // sign fixed
+                     dp -= (width_mmx*4 - 2);            // sign fixed
+                     for (i = width; i; i--)
+                     {
+                        png_byte v[8];
+                        int j;
+                        sptr -= 2;
+                        png_memcpy(v, sptr, 2);
+                        for (j = 0; j < png_pass_inc[pass]; j++)
+                        {
+                           dp -= 2;
+                           png_memcpy(dp, v, 2);
+                        }
+                     }
+                  }
+                  else if (((pass == 2) || (pass == 3)) && width)
+                  {
+                     int width_mmx = ((width >> 1) << 1) ;
+                     width -= width_mmx;
+                     if (width_mmx)
+                     {
+                        _asm
+                        {
+                           mov esi, sptr
+                           mov edi, dp
+                           mov ecx, width_mmx
+                           sub esi, 2
+                           sub edi, 14
+loop2_pass2:
+                           movd mm0, [esi]        ; X X X X v1 v0 v3 v2
+                           punpcklwd mm0, mm0     ; v1 v0 v1 v0 v3 v2 v3 v2
+                           movq mm1, mm0          ; v1 v0 v1 v0 v3 v2 v3 v2
+                           punpckldq mm0, mm0     ; v3 v2 v3 v2 v3 v2 v3 v2
+                           punpckhdq mm1, mm1     ; v1 v0 v1 v0 v1 v0 v1 v0
+                           movq [edi], mm0
+                           sub esi, 4
+                           movq [edi + 8], mm1
+                           //sub esi, 4
+                           sub edi, 16
+                           sub ecx, 2
+                           jnz loop2_pass2
+                           EMMS
+                        }
+                     }
+
+                     sptr -= (width_mmx*2 - 2);            // sign fixed
+                     dp -= (width_mmx*8 - 2);            // sign fixed
+                     for (i = width; i; i--)
+                     {
+                        png_byte v[8];
+                        int j;
+                        sptr -= 2;
+                        png_memcpy(v, sptr, 2);
+                        for (j = 0; j < png_pass_inc[pass]; j++)
+                        {
+                           dp -= 2;
+                           png_memcpy(dp, v, 2);
+                        }
+                     }
+                  }
+                  else if (width) /* && ((pass == 0) || (pass == 1))) */
+                  {
+                     int width_mmx = ((width >> 1) << 1);
+                     width -= width_mmx;
+                     if (width_mmx)
+                     {
+                        _asm
+                        {
+                           mov esi, sptr
+                           mov edi, dp
+                           mov ecx, width_mmx
+                           sub esi, 2
+                           sub edi, 30
+loop2_pass0:
+                           movd mm0, [esi]        ; X X X X v1 v0 v3 v2
+                           punpcklwd mm0, mm0     ; v1 v0 v1 v0 v3 v2 v3 v2
+                           movq mm1, mm0          ; v1 v0 v1 v0 v3 v2 v3 v2
+                           punpckldq mm0, mm0     ; v3 v2 v3 v2 v3 v2 v3 v2
+                           punpckhdq mm1, mm1     ; v1 v0 v1 v0 v1 v0 v1 v0
+                           movq [edi], mm0
+                           movq [edi + 8], mm0
+                           movq [edi + 16], mm1
+                           movq [edi + 24], mm1
+                           sub esi, 4
+                           sub edi, 32
+                           sub ecx, 2
+                           jnz loop2_pass0
+                           EMMS
+                        }
+                     }
+
+                     sptr -= (width_mmx*2 - 2);            // sign fixed
+                     dp -= (width_mmx*16 - 2);            // sign fixed
+                     for (i = width; i; i--)
+                     {
+                        png_byte v[8];
+                        int j;
+                        sptr -= 2;
+                        png_memcpy(v, sptr, 2);
+                        for (j = 0; j < png_pass_inc[pass]; j++)
+                        {
+                           dp -= 2;
+                           png_memcpy(dp, v, 2);
+                        }
+                     }
+                  }
+               } /* end of pixel_bytes == 2 */
+
+               else if (pixel_bytes == 4)
+               {
+                  if (((pass == 4) || (pass == 5)) && width)
+                  {
+                     int width_mmx = ((width >> 1) << 1) ;
+                     width -= width_mmx;
+                     if (width_mmx)
+                     {
+                        _asm
+                        {
+                           mov esi, sptr
+                           mov edi, dp
+                           mov ecx, width_mmx
+                           sub esi, 4
+                           sub edi, 12
+loop4_pass4:
+                           movq mm0, [esi]      ; v3 v2 v1 v0 v7 v6 v5 v4
+                           movq mm1, mm0        ; v3 v2 v1 v0 v7 v6 v5 v4
+                           punpckldq mm0, mm0   ; v7 v6 v5 v4 v7 v6 v5 v4
+                           punpckhdq mm1, mm1   ; v3 v2 v1 v0 v3 v2 v1 v0
+                           movq [edi], mm0
+                           sub esi, 8
+                           movq [edi + 8], mm1
+                           sub edi, 16
+                           sub ecx, 2
+                           jnz loop4_pass4
+                           EMMS
+                        }
+                     }
+
+                     sptr -= (width_mmx*4 - 4);          // sign fixed
+                     dp -= (width_mmx*8 - 4);            // sign fixed
+                     for (i = width; i; i--)
+                     {
+                        png_byte v[8];
+                        int j;
+                        sptr -= 4;
+                        png_memcpy(v, sptr, 4);
+                        for (j = 0; j < png_pass_inc[pass]; j++)
+                        {
+                           dp -= 4;
+                           png_memcpy(dp, v, 4);
+                        }
+                     }
+                  }
+                  else if (((pass == 2) || (pass == 3)) && width)
+                  {
+                     int width_mmx = ((width >> 1) << 1) ;
+                     width -= width_mmx;
+                     if (width_mmx)
+                     {
+                        _asm
+                        {
+                           mov esi, sptr
+                           mov edi, dp
+                           mov ecx, width_mmx
+                           sub esi, 4
+                           sub edi, 28
+loop4_pass2:
+                           movq mm0, [esi]      ; v3 v2 v1 v0 v7 v6 v5 v4
+                           movq mm1, mm0        ; v3 v2 v1 v0 v7 v6 v5 v4
+                           punpckldq mm0, mm0   ; v7 v6 v5 v4 v7 v6 v5 v4
+                           punpckhdq mm1, mm1   ; v3 v2 v1 v0 v3 v2 v1 v0
+                           movq [edi], mm0
+                           movq [edi + 8], mm0
+                           movq [edi+16], mm1
+                           movq [edi + 24], mm1
+                           sub esi, 8
+                           sub edi, 32
+                           sub ecx, 2
+                           jnz loop4_pass2
+                           EMMS
+                        }
+                     }
+
+                     sptr -= (width_mmx*4 - 4);            // sign fixed
+                     dp -= (width_mmx*16 - 4);            // sign fixed
+                     for (i = width; i; i--)
+                     {
+                        png_byte v[8];
+                        int j;
+                        sptr -= 4;
+                        png_memcpy(v, sptr, 4);
+                        for (j = 0; j < png_pass_inc[pass]; j++)
+                        {
+                           dp -= 4;
+                           png_memcpy(dp, v, 4);
+                        }
+                     }
+                  }
+                  else if (width) /* && ((pass == 0) || (pass == 1))) */
+                  {
+                     int width_mmx = ((width >> 1) << 1) ;
+                     width -= width_mmx;
+                     if (width_mmx)
+                     {
+                        _asm
+                        {
+                           mov esi, sptr
+                           mov edi, dp
+                           mov ecx, width_mmx
+                           sub esi, 4
+                           sub edi, 60
+loop4_pass0:
+                           movq mm0, [esi]        ; v3 v2 v1 v0 v7 v6 v5 v4
+                           movq mm1, mm0          ; v3 v2 v1 v0 v7 v6 v5 v4
+                           punpckldq mm0, mm0     ; v7 v6 v5 v4 v7 v6 v5 v4
+                           punpckhdq mm1, mm1     ; v3 v2 v1 v0 v3 v2 v1 v0
+                           movq [edi], mm0
+                           movq [edi + 8], mm0
+                           movq [edi + 16], mm0
+                           movq [edi + 24], mm0
+                           movq [edi+32], mm1
+                           movq [edi + 40], mm1
+                           movq [edi+ 48], mm1
+                           sub esi, 8
+                           movq [edi + 56], mm1
+                           sub edi, 64
+                           sub ecx, 2
+                           jnz loop4_pass0
+                           EMMS
+                        }
+                     }
+
+                     sptr -= (width_mmx*4 - 4);            // sign fixed
+                     dp -= (width_mmx*32 - 4);            // sign fixed
+                     for (i = width; i; i--)
+                     {
+                        png_byte v[8];
+                        int j;
+                        sptr -= 4;
+                        png_memcpy(v, sptr, 4);
+                        for (j = 0; j < png_pass_inc[pass]; j++)
+                        {
+                           dp -= 4;
+                           png_memcpy(dp, v, 4);
+                        }
+                     }
+                  }
+
+               } /* end of pixel_bytes == 4 */
+
+               else if (pixel_bytes == 6)
+               {
+                  for (i = width; i; i--)
+                  {
+                     png_byte v[8];
+                     int j;
+                     png_memcpy(v, sptr, 6);
+                     for (j = 0; j < png_pass_inc[pass]; j++)
+                     {
+                        png_memcpy(dp, v, 6);
+                        dp -= 6;
+                     }
+                     sptr -= 6;
+                  }
+               } /* end of pixel_bytes == 6 */
+
+               else
+               {
+                  for (i = width; i; i--)
+                  {
+                     png_byte v[8];
+                     int j;
+                     png_memcpy(v, sptr, pixel_bytes);
+                     for (j = 0; j < png_pass_inc[pass]; j++)
+                     {
+                        png_memcpy(dp, v, pixel_bytes);
+                        dp -= pixel_bytes;
+                     }
+                     sptr-= pixel_bytes;
+                  }
+               }
+            } /* end of mmx_supported */
+
+            else /* MMX not supported:  use modified C code - takes advantage
+                  * of inlining of memcpy for a constant */
+            {
+               if (pixel_bytes == 1)
+               {
+                  for (i = width; i; i--)
+                  {
+                     int j;
+                     for (j = 0; j < png_pass_inc[pass]; j++)
+                        *dp-- = *sptr;
+                     sptr--;
+                  }
+               }
+               else if (pixel_bytes == 3)
+               {
+                  for (i = width; i; i--)
+                  {
+                     png_byte v[8];
+                     int j;
+                     png_memcpy(v, sptr, pixel_bytes);
+                     for (j = 0; j < png_pass_inc[pass]; j++)
+                     {
+                        png_memcpy(dp, v, pixel_bytes);
+                        dp -= pixel_bytes;
+                     }
+                     sptr -= pixel_bytes;
+                  }
+               }
+               else if (pixel_bytes == 2)
+               {
+                  for (i = width; i; i--)
+                  {
+                     png_byte v[8];
+                     int j;
+                     png_memcpy(v, sptr, pixel_bytes);
+                     for (j = 0; j < png_pass_inc[pass]; j++)
+                     {
+                        png_memcpy(dp, v, pixel_bytes);
+                        dp -= pixel_bytes;
+                     }
+                     sptr -= pixel_bytes;
+                  }
+               }
+               else if (pixel_bytes == 4)
+               {
+                  for (i = width; i; i--)
+                  {
+                     png_byte v[8];
+                     int j;
+                     png_memcpy(v, sptr, pixel_bytes);
+                     for (j = 0; j < png_pass_inc[pass]; j++)
+                     {
+                        png_memcpy(dp, v, pixel_bytes);
+                        dp -= pixel_bytes;
+                     }
+                     sptr -= pixel_bytes;
+                  }
+               }
+               else if (pixel_bytes == 6)
+               {
+                  for (i = width; i; i--)
+                  {
+                     png_byte v[8];
+                     int j;
+                     png_memcpy(v, sptr, pixel_bytes);
+                     for (j = 0; j < png_pass_inc[pass]; j++)
+                     {
+                        png_memcpy(dp, v, pixel_bytes);
+                        dp -= pixel_bytes;
+                     }
+                     sptr -= pixel_bytes;
+                  }
+               }
+               else
+               {
+                  for (i = width; i; i--)
+                  {
+                     png_byte v[8];
+                     int j;
+                     png_memcpy(v, sptr, pixel_bytes);
+                     for (j = 0; j < png_pass_inc[pass]; j++)
+                     {
+                        png_memcpy(dp, v, pixel_bytes);
+                        dp -= pixel_bytes;
+                     }
+                     sptr -= pixel_bytes;
+                  }
+               }
+
+            } /* end of MMX not supported */
+            break;
+         }
+      } /* end switch (row_info->pixel_depth) */
+
+      row_info->width = final_width;
+
+      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,final_width);
+   }
+
+}
+
+#endif /* PNG_READ_INTERLACING_SUPPORTED */
+
+
+// These global constants are declared
+// here to ensure alignment on 8-byte boundaries.
+  union uAll {
+     __int64 use;
+     double  double_align;
+     long long long_long_align;
+  } ;
+  static PNG_CONST union uAll LBCarryMask = {0x0101010101010101},
+                              HBClearMask = {0x7f7f7f7f7f7f7f7f};
+
+// Optimized code for PNG Average filter decoder
+void /* PRIVATE */
+png_read_filter_row_mmx_avg(png_row_infop row_info, png_bytep row
+                            , png_bytep prev_row)
+{
+  // These variables are declared
+  // here to ensure alignment on 8-byte boundaries.
+  union uAll ActiveMask, ShiftBpp, ShiftRem;
+
+   int bpp;
+   png_uint_32 FullLength;
+   png_uint_32 MMXLength;
+   //png_uint_32 len;
+   int diff;
+
+   bpp = (row_info->pixel_depth + 7) >> 3; // Get # bytes per pixel
+   FullLength  = row_info->rowbytes; // # of bytes to filter
+   _asm {
+         // Init address pointers and offset
+         mov edi, row          // edi ==> Avg(x)
+         xor ebx, ebx          // ebx ==> x
+         mov edx, edi
+         mov esi, prev_row           // esi ==> Prior(x)
+         sub edx, bpp          // edx ==> Raw(x-bpp)
+
+         xor eax, eax
+         // Compute the Raw value for the first bpp bytes
+         //    Raw(x) = Avg(x) + (Prior(x)/2)
+davgrlp:
+         mov al, [esi + ebx]   // Load al with Prior(x)
+         inc ebx
+         shr al, 1             // divide by 2
+         add al, [edi+ebx-1]   // Add Avg(x); -1 to offset inc ebx
+         cmp ebx, bpp
+         mov [edi+ebx-1], al    // Write back Raw(x);
+                            // mov does not affect flags; -1 to offset inc ebx
+         jb davgrlp
+         // get # of bytes to alignment
+         mov diff, edi         // take start of row
+         add diff, ebx         // add bpp
+         add diff, 0xf         // add 7 + 8 to incr past alignment boundary
+         and diff, 0xfffffff8  // mask to alignment boundary
+         sub diff, edi         // subtract from start ==> value ebx at alignment
+         jz davggo
+         // fix alignment
+         // Compute the Raw value for the bytes upto the alignment boundary
+         //    Raw(x) = Avg(x) + ((Raw(x-bpp) + Prior(x))/2)
+         xor ecx, ecx
+davglp1:
+         xor eax, eax
+         mov cl, [esi + ebx]        // load cl with Prior(x)
+         mov al, [edx + ebx]  // load al with Raw(x-bpp)
+         add ax, cx
+         inc ebx
+         shr ax, 1            // divide by 2
+         add al, [edi+ebx-1]  // Add Avg(x); -1 to offset inc ebx
+         cmp ebx, diff              // Check if at alignment boundary
+         mov [edi+ebx-1], al        // Write back Raw(x);
+                            // mov does not affect flags; -1 to offset inc ebx
+         jb davglp1               // Repeat until at alignment boundary
+davggo:
+         mov eax, FullLength
+         mov ecx, eax
+         sub eax, ebx          // subtract alignment fix
+         and eax, 0x00000007   // calc bytes over mult of 8
+         sub ecx, eax          // drop over bytes from original length
+         mov MMXLength, ecx
+   } // end _asm block
+   // Now do the math for the rest of the row
+   switch ( bpp )
+   {
+      case 3:
+      {
+         ActiveMask.use  = 0x0000000000ffffff;
+         ShiftBpp.use = 24;    // == 3 * 8
+         ShiftRem.use = 40;    // == 64 - 24
+         _asm {
+            // Re-init address pointers and offset
+            movq mm7, ActiveMask
+            mov ebx, diff      // ebx ==> x = offset to alignment boundary
+            movq mm5, LBCarryMask
+            mov edi, row       // edi ==> Avg(x)
+            movq mm4, HBClearMask
+            mov esi, prev_row        // esi ==> Prior(x)
+            // PRIME the pump (load the first Raw(x-bpp) data set
+            movq mm2, [edi + ebx - 8]  // Load previous aligned 8 bytes
+                               // (we correct position in loop below)
+davg3lp:
+            movq mm0, [edi + ebx]      // Load mm0 with Avg(x)
+            // Add (Prev_row/2) to Average
+            movq mm3, mm5
+            psrlq mm2, ShiftRem      // Correct position Raw(x-bpp) data
+            movq mm1, [esi + ebx]    // Load mm1 with Prior(x)
+            movq mm6, mm7
+            pand mm3, mm1      // get lsb for each prev_row byte
+            psrlq mm1, 1       // divide prev_row bytes by 2
+            pand  mm1, mm4     // clear invalid bit 7 of each byte
+            paddb mm0, mm1     // add (Prev_row/2) to Avg for each byte
+            // Add 1st active group (Raw(x-bpp)/2) to Average with LBCarry
+            movq mm1, mm3      // now use mm1 for getting LBCarrys
+            pand mm1, mm2      // get LBCarrys for each byte where both
+                               // lsb's were == 1 (Only valid for active group)
+            psrlq mm2, 1       // divide raw bytes by 2
+            pand  mm2, mm4     // clear invalid bit 7 of each byte
+            paddb mm2, mm1     // add LBCarrys to (Raw(x-bpp)/2) for each byte
+            pand mm2, mm6      // Leave only Active Group 1 bytes to add to Avg
+            paddb mm0, mm2     // add (Raw/2) + LBCarrys to Avg for each Active
+                               //  byte
+            // Add 2nd active group (Raw(x-bpp)/2) to Average with LBCarry
+            psllq mm6, ShiftBpp  // shift the mm6 mask to cover bytes 3-5
+            movq mm2, mm0        // mov updated Raws to mm2
+            psllq mm2, ShiftBpp  // shift data to position correctly
+            movq mm1, mm3        // now use mm1 for getting LBCarrys
+            pand mm1, mm2      // get LBCarrys for each byte where both
+                               // lsb's were == 1 (Only valid for active group)
+            psrlq mm2, 1       // divide raw bytes by 2
+            pand  mm2, mm4     // clear invalid bit 7 of each byte
+            paddb mm2, mm1     // add LBCarrys to (Raw(x-bpp)/2) for each byte
+            pand mm2, mm6      // Leave only Active Group 2 bytes to add to Avg
+            paddb mm0, mm2     // add (Raw/2) + LBCarrys to Avg for each Active
+                               //  byte
+
+            // Add 3rd active group (Raw(x-bpp)/2) to Average with LBCarry
+            psllq mm6, ShiftBpp  // shift the mm6 mask to cover the last two
+                                 // bytes
+            movq mm2, mm0        // mov updated Raws to mm2
+            psllq mm2, ShiftBpp  // shift data to position correctly
+                              // Data only needs to be shifted once here to
+                              // get the correct x-bpp offset.
+            movq mm1, mm3     // now use mm1 for getting LBCarrys
+            pand mm1, mm2     // get LBCarrys for each byte where both
+                              // lsb's were == 1 (Only valid for active group)
+            psrlq mm2, 1      // divide raw bytes by 2
+            pand  mm2, mm4    // clear invalid bit 7 of each byte
+            paddb mm2, mm1    // add LBCarrys to (Raw(x-bpp)/2) for each byte
+            pand mm2, mm6     // Leave only Active Group 2 bytes to add to Avg
+            add ebx, 8
+            paddb mm0, mm2    // add (Raw/2) + LBCarrys to Avg for each Active
+                              // byte
+
+            // Now ready to write back to memory
+            movq [edi + ebx - 8], mm0
+            // Move updated Raw(x) to use as Raw(x-bpp) for next loop
+            cmp ebx, MMXLength
+            movq mm2, mm0     // mov updated Raw(x) to mm2
+            jb davg3lp
+         } // end _asm block
+      }
+      break;
+
+      case 6:
+      case 4:
+      case 7:
+      case 5:
+      {
+         ActiveMask.use  = 0xffffffffffffffff;  // use shift below to clear
+                                                // appropriate inactive bytes
+         ShiftBpp.use = bpp << 3;
+         ShiftRem.use = 64 - ShiftBpp.use;
+         _asm {
+            movq mm4, HBClearMask
+            // Re-init address pointers and offset
+            mov ebx, diff       // ebx ==> x = offset to alignment boundary
+            // Load ActiveMask and clear all bytes except for 1st active group
+            movq mm7, ActiveMask
+            mov edi, row         // edi ==> Avg(x)
+            psrlq mm7, ShiftRem
+            mov esi, prev_row    // esi ==> Prior(x)
+            movq mm6, mm7
+            movq mm5, LBCarryMask
+            psllq mm6, ShiftBpp  // Create mask for 2nd active group
+            // PRIME the pump (load the first Raw(x-bpp) data set
+            movq mm2, [edi + ebx - 8]  // Load previous aligned 8 bytes
+                                 // (we correct position in loop below)
+davg4lp:
+            movq mm0, [edi + ebx]
+            psrlq mm2, ShiftRem  // shift data to position correctly
+            movq mm1, [esi + ebx]
+            // Add (Prev_row/2) to Average
+            movq mm3, mm5
+            pand mm3, mm1     // get lsb for each prev_row byte
+            psrlq mm1, 1      // divide prev_row bytes by 2
+            pand  mm1, mm4    // clear invalid bit 7 of each byte
+            paddb mm0, mm1    // add (Prev_row/2) to Avg for each byte
+            // Add 1st active group (Raw(x-bpp)/2) to Average with LBCarry
+            movq mm1, mm3     // now use mm1 for getting LBCarrys
+            pand mm1, mm2     // get LBCarrys for each byte where both
+                              // lsb's were == 1 (Only valid for active group)
+            psrlq mm2, 1      // divide raw bytes by 2
+            pand  mm2, mm4    // clear invalid bit 7 of each byte
+            paddb mm2, mm1    // add LBCarrys to (Raw(x-bpp)/2) for each byte
+            pand mm2, mm7     // Leave only Active Group 1 bytes to add to Avg
+            paddb mm0, mm2    // add (Raw/2) + LBCarrys to Avg for each Active
+                              // byte
+            // Add 2nd active group (Raw(x-bpp)/2) to Average with LBCarry
+            movq mm2, mm0     // mov updated Raws to mm2
+            psllq mm2, ShiftBpp // shift data to position correctly
+            add ebx, 8
+            movq mm1, mm3     // now use mm1 for getting LBCarrys
+            pand mm1, mm2     // get LBCarrys for each byte where both
+                              // lsb's were == 1 (Only valid for active group)
+            psrlq mm2, 1      // divide raw bytes by 2
+            pand  mm2, mm4    // clear invalid bit 7 of each byte
+            paddb mm2, mm1    // add LBCarrys to (Raw(x-bpp)/2) for each byte
+            pand mm2, mm6     // Leave only Active Group 2 bytes to add to Avg
+            paddb mm0, mm2    // add (Raw/2) + LBCarrys to Avg for each Active
+                              // byte
+            cmp ebx, MMXLength
+            // Now ready to write back to memory
+            movq [edi + ebx - 8], mm0
+            // Prep Raw(x-bpp) for next loop
+            movq mm2, mm0     // mov updated Raws to mm2
+            jb davg4lp
+         } // end _asm block
+      }
+      break;
+      case 2:
+      {
+         ActiveMask.use  = 0x000000000000ffff;
+         ShiftBpp.use = 16;   // == 2 * 8     [BUGFIX]
+         ShiftRem.use = 48;   // == 64 - 16   [BUGFIX]
+         _asm {
+            // Load ActiveMask
+            movq mm7, ActiveMask
+            // Re-init address pointers and offset
+            mov ebx, diff     // ebx ==> x = offset to alignment boundary
+            movq mm5, LBCarryMask
+            mov edi, row      // edi ==> Avg(x)
+            movq mm4, HBClearMask
+            mov esi, prev_row  // esi ==> Prior(x)
+            // PRIME the pump (load the first Raw(x-bpp) data set
+            movq mm2, [edi + ebx - 8]  // Load previous aligned 8 bytes
+                              // (we correct position in loop below)
+davg2lp:
+            movq mm0, [edi + ebx]
+            psrlq mm2, ShiftRem  // shift data to position correctly   [BUGFIX]
+            movq mm1, [esi + ebx]
+            // Add (Prev_row/2) to Average
+            movq mm3, mm5
+            pand mm3, mm1     // get lsb for each prev_row byte
+            psrlq mm1, 1      // divide prev_row bytes by 2
+            pand  mm1, mm4    // clear invalid bit 7 of each byte
+            movq mm6, mm7
+            paddb mm0, mm1    // add (Prev_row/2) to Avg for each byte
+            // Add 1st active group (Raw(x-bpp)/2) to Average with LBCarry
+            movq mm1, mm3     // now use mm1 for getting LBCarrys
+            pand mm1, mm2     // get LBCarrys for each byte where both
+                              // lsb's were == 1 (Only valid for active group)
+            psrlq mm2, 1      // divide raw bytes by 2
+            pand  mm2, mm4    // clear invalid bit 7 of each byte
+            paddb mm2, mm1    // add LBCarrys to (Raw(x-bpp)/2) for each byte
+            pand mm2, mm6     // Leave only Active Group 1 bytes to add to Avg
+            paddb mm0, mm2 // add (Raw/2) + LBCarrys to Avg for each Active byte
+            // Add 2nd active group (Raw(x-bpp)/2) to Average with LBCarry
+            psllq mm6, ShiftBpp // shift the mm6 mask to cover bytes 2 & 3
+            movq mm2, mm0       // mov updated Raws to mm2
+            psllq mm2, ShiftBpp // shift data to position correctly
+            movq mm1, mm3       // now use mm1 for getting LBCarrys
+            pand mm1, mm2       // get LBCarrys for each byte where both
+                                // lsb's were == 1 (Only valid for active group)
+            psrlq mm2, 1        // divide raw bytes by 2
+            pand  mm2, mm4      // clear invalid bit 7 of each byte
+            paddb mm2, mm1      // add LBCarrys to (Raw(x-bpp)/2) for each byte
+            pand mm2, mm6       // Leave only Active Group 2 bytes to add to Avg
+            paddb mm0, mm2 // add (Raw/2) + LBCarrys to Avg for each Active byte
+
+            // Add rdd active group (Raw(x-bpp)/2) to Average with LBCarry
+            psllq mm6, ShiftBpp // shift the mm6 mask to cover bytes 4 & 5
+            movq mm2, mm0       // mov updated Raws to mm2
+            psllq mm2, ShiftBpp // shift data to position correctly
+                                // Data only needs to be shifted once here to
+                                // get the correct x-bpp offset.
+            movq mm1, mm3       // now use mm1 for getting LBCarrys
+            pand mm1, mm2       // get LBCarrys for each byte where both
+                                // lsb's were == 1 (Only valid for active group)
+            psrlq mm2, 1        // divide raw bytes by 2
+            pand  mm2, mm4      // clear invalid bit 7 of each byte
+            paddb mm2, mm1      // add LBCarrys to (Raw(x-bpp)/2) for each byte
+            pand mm2, mm6       // Leave only Active Group 2 bytes to add to Avg
+            paddb mm0, mm2 // add (Raw/2) + LBCarrys to Avg for each Active byte
+
+            // Add 4th active group (Raw(x-bpp)/2) to Average with LBCarry
+            psllq mm6, ShiftBpp  // shift the mm6 mask to cover bytes 6 & 7
+            movq mm2, mm0        // mov updated Raws to mm2
+            psllq mm2, ShiftBpp  // shift data to position correctly
+                                 // Data only needs to be shifted once here to
+                                 // get the correct x-bpp offset.
+            add ebx, 8
+            movq mm1, mm3    // now use mm1 for getting LBCarrys
+            pand mm1, mm2    // get LBCarrys for each byte where both
+                             // lsb's were == 1 (Only valid for active group)
+            psrlq mm2, 1     // divide raw bytes by 2
+            pand  mm2, mm4   // clear invalid bit 7 of each byte
+            paddb mm2, mm1   // add LBCarrys to (Raw(x-bpp)/2) for each byte
+            pand mm2, mm6    // Leave only Active Group 2 bytes to add to Avg
+            paddb mm0, mm2 // add (Raw/2) + LBCarrys to Avg for each Active byte
+
+            cmp ebx, MMXLength
+            // Now ready to write back to memory
+            movq [edi + ebx - 8], mm0
+            // Prep Raw(x-bpp) for next loop
+            movq mm2, mm0    // mov updated Raws to mm2
+            jb davg2lp
+        } // end _asm block
+      }
+      break;
+
+      case 1:                 // bpp == 1
+      {
+         _asm {
+            // Re-init address pointers and offset
+            mov ebx, diff     // ebx ==> x = offset to alignment boundary
+            mov edi, row      // edi ==> Avg(x)
+            cmp ebx, FullLength  // Test if offset at end of array
+            jnb davg1end
+            // Do Paeth decode for remaining bytes
+            mov esi, prev_row    // esi ==> Prior(x)
+            mov edx, edi
+            xor ecx, ecx         // zero ecx before using cl & cx in loop below
+            sub edx, bpp         // edx ==> Raw(x-bpp)
+davg1lp:
+            // Raw(x) = Avg(x) + ((Raw(x-bpp) + Prior(x))/2)
+            xor eax, eax
+            mov cl, [esi + ebx]  // load cl with Prior(x)
+            mov al, [edx + ebx]  // load al with Raw(x-bpp)
+            add ax, cx
+            inc ebx
+            shr ax, 1            // divide by 2
+            add al, [edi+ebx-1]  // Add Avg(x); -1 to offset inc ebx
+            cmp ebx, FullLength  // Check if at end of array
+            mov [edi+ebx-1], al  // Write back Raw(x);
+                         // mov does not affect flags; -1 to offset inc ebx
+            jb davg1lp
+davg1end:
+         } // end _asm block
+      }
+      return;
+
+      case 8:             // bpp == 8
+      {
+         _asm {
+            // Re-init address pointers and offset
+            mov ebx, diff           // ebx ==> x = offset to alignment boundary
+            movq mm5, LBCarryMask
+            mov edi, row            // edi ==> Avg(x)
+            movq mm4, HBClearMask
+            mov esi, prev_row       // esi ==> Prior(x)
+            // PRIME the pump (load the first Raw(x-bpp) data set
+            movq mm2, [edi + ebx - 8]  // Load previous aligned 8 bytes
+                                // (NO NEED to correct position in loop below)
+davg8lp:
+            movq mm0, [edi + ebx]
+            movq mm3, mm5
+            movq mm1, [esi + ebx]
+            add ebx, 8
+            pand mm3, mm1       // get lsb for each prev_row byte
+            psrlq mm1, 1        // divide prev_row bytes by 2
+            pand mm3, mm2       // get LBCarrys for each byte where both
+                                // lsb's were == 1
+            psrlq mm2, 1        // divide raw bytes by 2
+            pand  mm1, mm4      // clear invalid bit 7 of each byte
+            paddb mm0, mm3      // add LBCarrys to Avg for each byte
+            pand  mm2, mm4      // clear invalid bit 7 of each byte
+            paddb mm0, mm1      // add (Prev_row/2) to Avg for each byte
+            paddb mm0, mm2      // add (Raw/2) to Avg for each byte
+            cmp ebx, MMXLength
+            movq [edi + ebx - 8], mm0
+            movq mm2, mm0       // reuse as Raw(x-bpp)
+            jb davg8lp
+        } // end _asm block
+      }
+      break;
+      default:                  // bpp greater than 8
+      {
+        _asm {
+            movq mm5, LBCarryMask
+            // Re-init address pointers and offset
+            mov ebx, diff       // ebx ==> x = offset to alignment boundary
+            mov edi, row        // edi ==> Avg(x)
+            movq mm4, HBClearMask
+            mov edx, edi
+            mov esi, prev_row   // esi ==> Prior(x)
+            sub edx, bpp        // edx ==> Raw(x-bpp)
+davgAlp:
+            movq mm0, [edi + ebx]
+            movq mm3, mm5
+            movq mm1, [esi + ebx]
+            pand mm3, mm1       // get lsb for each prev_row byte
+            movq mm2, [edx + ebx]
+            psrlq mm1, 1        // divide prev_row bytes by 2
+            pand mm3, mm2       // get LBCarrys for each byte where both
+                                // lsb's were == 1
+            psrlq mm2, 1        // divide raw bytes by 2
+            pand  mm1, mm4      // clear invalid bit 7 of each byte
+            paddb mm0, mm3      // add LBCarrys to Avg for each byte
+            pand  mm2, mm4      // clear invalid bit 7 of each byte
+            paddb mm0, mm1      // add (Prev_row/2) to Avg for each byte
+            add ebx, 8
+            paddb mm0, mm2      // add (Raw/2) to Avg for each byte
+            cmp ebx, MMXLength
+            movq [edi + ebx - 8], mm0
+            jb davgAlp
+        } // end _asm block
+      }
+      break;
+   }                         // end switch ( bpp )
+
+   _asm {
+         // MMX acceleration complete now do clean-up
+         // Check if any remaining bytes left to decode
+         mov ebx, MMXLength    // ebx ==> x = offset bytes remaining after MMX
+         mov edi, row          // edi ==> Avg(x)
+         cmp ebx, FullLength   // Test if offset at end of array
+         jnb davgend
+         // Do Paeth decode for remaining bytes
+         mov esi, prev_row     // esi ==> Prior(x)
+         mov edx, edi
+         xor ecx, ecx          // zero ecx before using cl & cx in loop below
+         sub edx, bpp          // edx ==> Raw(x-bpp)
+davglp2:
+         // Raw(x) = Avg(x) + ((Raw(x-bpp) + Prior(x))/2)
+         xor eax, eax
+         mov cl, [esi + ebx]   // load cl with Prior(x)
+         mov al, [edx + ebx]   // load al with Raw(x-bpp)
+         add ax, cx
+         inc ebx
+         shr ax, 1              // divide by 2
+         add al, [edi+ebx-1]    // Add Avg(x); -1 to offset inc ebx
+         cmp ebx, FullLength    // Check if at end of array
+         mov [edi+ebx-1], al    // Write back Raw(x);
+                          // mov does not affect flags; -1 to offset inc ebx
+         jb davglp2
+davgend:
+         emms             // End MMX instructions; prep for possible FP instrs.
+   } // end _asm block
+}
+
+// Optimized code for PNG Paeth filter decoder
+void /* PRIVATE */
+png_read_filter_row_mmx_paeth(png_row_infop row_info, png_bytep row,
+                              png_bytep prev_row)
+{
+  // These variables are declared
+  // here to ensure alignment on 8-byte boundaries.
+  union uAll  ActiveMask, ActiveMask2, ActiveMaskEnd, ShiftBpp, ShiftRem;
+
+   png_uint_32 FullLength;
+   png_uint_32 MMXLength;
+   //png_uint_32 len;
+   int bpp;
+   int diff;
+   //int ptemp;
+   int patemp, pbtemp, pctemp;
+
+   bpp = (row_info->pixel_depth + 7) >> 3; // Get # bytes per pixel
+   FullLength  = row_info->rowbytes; // # of bytes to filter
+   _asm
+   {
+         xor ebx, ebx        // ebx ==> x offset
+         mov edi, row
+         xor edx, edx        // edx ==> x-bpp offset
+         mov esi, prev_row
+         xor eax, eax
+
+         // Compute the Raw value for the first bpp bytes
+         // Note: the formula works out to be always
+         //   Paeth(x) = Raw(x) + Prior(x)      where x < bpp
+dpthrlp:
+         mov al, [edi + ebx]
+         add al, [esi + ebx]
+         inc ebx
+         cmp ebx, bpp
+         mov [edi + ebx - 1], al
+         jb dpthrlp
+         // get # of bytes to alignment
+         mov diff, edi         // take start of row
+         add diff, ebx         // add bpp
+         xor ecx, ecx
+         add diff, 0xf         // add 7 + 8 to incr past alignment boundary
+         and diff, 0xfffffff8  // mask to alignment boundary
+         sub diff, edi         // subtract from start ==> value ebx at alignment
+         jz dpthgo
+         // fix alignment
+dpthlp1:
+         xor eax, eax
+         // pav = p - a = (a + b - c) - a = b - c
+         mov al, [esi + ebx]   // load Prior(x) into al
+         mov cl, [esi + edx]   // load Prior(x-bpp) into cl
+         sub eax, ecx          // subtract Prior(x-bpp)
+         mov patemp, eax       // Save pav for later use
+         xor eax, eax
+         // pbv = p - b = (a + b - c) - b = a - c
+         mov al, [edi + edx]   // load Raw(x-bpp) into al
+         sub eax, ecx          // subtract Prior(x-bpp)
+         mov ecx, eax
+         // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+         add eax, patemp       // pcv = pav + pbv
+         // pc = abs(pcv)
+         test eax, 0x80000000
+         jz dpthpca
+         neg eax               // reverse sign of neg values
+dpthpca:
+         mov pctemp, eax       // save pc for later use
+         // pb = abs(pbv)
+         test ecx, 0x80000000
+         jz dpthpba
+         neg ecx               // reverse sign of neg values
+dpthpba:
+         mov pbtemp, ecx       // save pb for later use
+         // pa = abs(pav)
+         mov eax, patemp
+         test eax, 0x80000000
+         jz dpthpaa
+         neg eax               // reverse sign of neg values
+dpthpaa:
+         mov patemp, eax       // save pa for later use
+         // test if pa <= pb
+         cmp eax, ecx
+         jna dpthabb
+         // pa > pb; now test if pb <= pc
+         cmp ecx, pctemp
+         jna dpthbbc
+         // pb > pc; Raw(x) = Paeth(x) + Prior(x-bpp)
+         mov cl, [esi + edx]  // load Prior(x-bpp) into cl
+         jmp dpthpaeth
+dpthbbc:
+         // pb <= pc; Raw(x) = Paeth(x) + Prior(x)
+         mov cl, [esi + ebx]   // load Prior(x) into cl
+         jmp dpthpaeth
+dpthabb:
+         // pa <= pb; now test if pa <= pc
+         cmp eax, pctemp
+         jna dpthabc
+         // pa > pc; Raw(x) = Paeth(x) + Prior(x-bpp)
+         mov cl, [esi + edx]  // load Prior(x-bpp) into cl
+         jmp dpthpaeth
+dpthabc:
+         // pa <= pc; Raw(x) = Paeth(x) + Raw(x-bpp)
+         mov cl, [edi + edx]  // load Raw(x-bpp) into cl
+dpthpaeth:
+         inc ebx
+         inc edx
+         // Raw(x) = (Paeth(x) + Paeth_Predictor( a, b, c )) mod 256
+         add [edi + ebx - 1], cl
+         cmp ebx, diff
+         jb dpthlp1
+dpthgo:
+         mov ecx, FullLength
+         mov eax, ecx
+         sub eax, ebx          // subtract alignment fix
+         and eax, 0x00000007   // calc bytes over mult of 8
+         sub ecx, eax          // drop over bytes from original length
+         mov MMXLength, ecx
+   } // end _asm block
+   // Now do the math for the rest of the row
+   switch ( bpp )
+   {
+      case 3:
+      {
+         ActiveMask.use = 0x0000000000ffffff;
+         ActiveMaskEnd.use = 0xffff000000000000;
+         ShiftBpp.use = 24;    // == bpp(3) * 8
+         ShiftRem.use = 40;    // == 64 - 24
+         _asm
+         {
+            mov ebx, diff
+            mov edi, row
+            mov esi, prev_row
+            pxor mm0, mm0
+            // PRIME the pump (load the first Raw(x-bpp) data set
+            movq mm1, [edi+ebx-8]
+dpth3lp:
+            psrlq mm1, ShiftRem     // shift last 3 bytes to 1st 3 bytes
+            movq mm2, [esi + ebx]   // load b=Prior(x)
+            punpcklbw mm1, mm0      // Unpack High bytes of a
+            movq mm3, [esi+ebx-8]   // Prep c=Prior(x-bpp) bytes
+            punpcklbw mm2, mm0      // Unpack High bytes of b
+            psrlq mm3, ShiftRem     // shift last 3 bytes to 1st 3 bytes
+            // pav = p - a = (a + b - c) - a = b - c
+            movq mm4, mm2
+            punpcklbw mm3, mm0      // Unpack High bytes of c
+            // pbv = p - b = (a + b - c) - b = a - c
+            movq mm5, mm1
+            psubw mm4, mm3
+            pxor mm7, mm7
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+            movq mm6, mm4
+            psubw mm5, mm3
+
+            // pa = abs(p-a) = abs(pav)
+            // pb = abs(p-b) = abs(pbv)
+            // pc = abs(p-c) = abs(pcv)
+            pcmpgtw mm0, mm4    // Create mask pav bytes < 0
+            paddw mm6, mm5
+            pand mm0, mm4       // Only pav bytes < 0 in mm7
+            pcmpgtw mm7, mm5    // Create mask pbv bytes < 0
+            psubw mm4, mm0
+            pand mm7, mm5       // Only pbv bytes < 0 in mm0
+            psubw mm4, mm0
+            psubw mm5, mm7
+            pxor mm0, mm0
+            pcmpgtw mm0, mm6    // Create mask pcv bytes < 0
+            pand mm0, mm6       // Only pav bytes < 0 in mm7
+            psubw mm5, mm7
+            psubw mm6, mm0
+            //  test pa <= pb
+            movq mm7, mm4
+            psubw mm6, mm0
+            pcmpgtw mm7, mm5    // pa > pb?
+            movq mm0, mm7
+            // use mm7 mask to merge pa & pb
+            pand mm5, mm7
+            // use mm0 mask copy to merge a & b
+            pand mm2, mm0
+            pandn mm7, mm4
+            pandn mm0, mm1
+            paddw mm7, mm5
+            paddw mm0, mm2
+            //  test  ((pa <= pb)? pa:pb) <= pc
+            pcmpgtw mm7, mm6       // pab > pc?
+            pxor mm1, mm1
+            pand mm3, mm7
+            pandn mm7, mm0
+            paddw mm7, mm3
+            pxor mm0, mm0
+            packuswb mm7, mm1
+            movq mm3, [esi + ebx]   // load c=Prior(x-bpp)
+            pand mm7, ActiveMask
+            movq mm2, mm3           // load b=Prior(x) step 1
+            paddb mm7, [edi + ebx]  // add Paeth predictor with Raw(x)
+            punpcklbw mm3, mm0      // Unpack High bytes of c
+            movq [edi + ebx], mm7   // write back updated value
+            movq mm1, mm7           // Now mm1 will be used as Raw(x-bpp)
+            // Now do Paeth for 2nd set of bytes (3-5)
+            psrlq mm2, ShiftBpp     // load b=Prior(x) step 2
+            punpcklbw mm1, mm0      // Unpack High bytes of a
+            pxor mm7, mm7
+            punpcklbw mm2, mm0      // Unpack High bytes of b
+            // pbv = p - b = (a + b - c) - b = a - c
+            movq mm5, mm1
+            // pav = p - a = (a + b - c) - a = b - c
+            movq mm4, mm2
+            psubw mm5, mm3
+            psubw mm4, mm3
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) =
+            //       pav + pbv = pbv + pav
+            movq mm6, mm5
+            paddw mm6, mm4
+
+            // pa = abs(p-a) = abs(pav)
+            // pb = abs(p-b) = abs(pbv)
+            // pc = abs(p-c) = abs(pcv)
+            pcmpgtw mm0, mm5       // Create mask pbv bytes < 0
+            pcmpgtw mm7, mm4       // Create mask pav bytes < 0
+            pand mm0, mm5          // Only pbv bytes < 0 in mm0
+            pand mm7, mm4          // Only pav bytes < 0 in mm7
+            psubw mm5, mm0
+            psubw mm4, mm7
+            psubw mm5, mm0
+            psubw mm4, mm7
+            pxor mm0, mm0
+            pcmpgtw mm0, mm6       // Create mask pcv bytes < 0
+            pand mm0, mm6          // Only pav bytes < 0 in mm7
+            psubw mm6, mm0
+            //  test pa <= pb
+            movq mm7, mm4
+            psubw mm6, mm0
+            pcmpgtw mm7, mm5       // pa > pb?
+            movq mm0, mm7
+            // use mm7 mask to merge pa & pb
+            pand mm5, mm7
+            // use mm0 mask copy to merge a & b
+            pand mm2, mm0
+            pandn mm7, mm4
+            pandn mm0, mm1
+            paddw mm7, mm5
+            paddw mm0, mm2
+            //  test  ((pa <= pb)? pa:pb) <= pc
+            pcmpgtw mm7, mm6       // pab > pc?
+            movq mm2, [esi + ebx]  // load b=Prior(x)
+            pand mm3, mm7
+            pandn mm7, mm0
+            pxor mm1, mm1
+            paddw mm7, mm3
+            pxor mm0, mm0
+            packuswb mm7, mm1
+            movq mm3, mm2           // load c=Prior(x-bpp) step 1
+            pand mm7, ActiveMask
+            punpckhbw mm2, mm0      // Unpack High bytes of b
+            psllq mm7, ShiftBpp     // Shift bytes to 2nd group of 3 bytes
+             // pav = p - a = (a + b - c) - a = b - c
+            movq mm4, mm2
+            paddb mm7, [edi + ebx]  // add Paeth predictor with Raw(x)
+            psllq mm3, ShiftBpp     // load c=Prior(x-bpp) step 2
+            movq [edi + ebx], mm7   // write back updated value
+            movq mm1, mm7
+            punpckhbw mm3, mm0      // Unpack High bytes of c
+            psllq mm1, ShiftBpp     // Shift bytes
+                                    // Now mm1 will be used as Raw(x-bpp)
+            // Now do Paeth for 3rd, and final, set of bytes (6-7)
+            pxor mm7, mm7
+            punpckhbw mm1, mm0      // Unpack High bytes of a
+            psubw mm4, mm3
+            // pbv = p - b = (a + b - c) - b = a - c
+            movq mm5, mm1
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+            movq mm6, mm4
+            psubw mm5, mm3
+            pxor mm0, mm0
+            paddw mm6, mm5
+
+            // pa = abs(p-a) = abs(pav)
+            // pb = abs(p-b) = abs(pbv)
+            // pc = abs(p-c) = abs(pcv)
+            pcmpgtw mm0, mm4    // Create mask pav bytes < 0
+            pcmpgtw mm7, mm5    // Create mask pbv bytes < 0
+            pand mm0, mm4       // Only pav bytes < 0 in mm7
+            pand mm7, mm5       // Only pbv bytes < 0 in mm0
+            psubw mm4, mm0
+            psubw mm5, mm7
+            psubw mm4, mm0
+            psubw mm5, mm7
+            pxor mm0, mm0
+            pcmpgtw mm0, mm6    // Create mask pcv bytes < 0
+            pand mm0, mm6       // Only pav bytes < 0 in mm7
+            psubw mm6, mm0
+            //  test pa <= pb
+            movq mm7, mm4
+            psubw mm6, mm0
+            pcmpgtw mm7, mm5    // pa > pb?
+            movq mm0, mm7
+            // use mm0 mask copy to merge a & b
+            pand mm2, mm0
+            // use mm7 mask to merge pa & pb
+            pand mm5, mm7
+            pandn mm0, mm1
+            pandn mm7, mm4
+            paddw mm0, mm2
+            paddw mm7, mm5
+            //  test  ((pa <= pb)? pa:pb) <= pc
+            pcmpgtw mm7, mm6    // pab > pc?
+            pand mm3, mm7
+            pandn mm7, mm0
+            paddw mm7, mm3
+            pxor mm1, mm1
+            packuswb mm1, mm7
+            // Step ebx to next set of 8 bytes and repeat loop til done
+            add ebx, 8
+            pand mm1, ActiveMaskEnd
+            paddb mm1, [edi + ebx - 8] // add Paeth predictor with Raw(x)
+
+            cmp ebx, MMXLength
+            pxor mm0, mm0              // pxor does not affect flags
+            movq [edi + ebx - 8], mm1  // write back updated value
+                                 // mm1 will be used as Raw(x-bpp) next loop
+                           // mm3 ready to be used as Prior(x-bpp) next loop
+            jb dpth3lp
+         } // end _asm block
+      }
+      break;
+
+      case 6:
+      case 7:
+      case 5:
+      {
+         ActiveMask.use  = 0x00000000ffffffff;
+         ActiveMask2.use = 0xffffffff00000000;
+         ShiftBpp.use = bpp << 3;    // == bpp * 8
+         ShiftRem.use = 64 - ShiftBpp.use;
+         _asm
+         {
+            mov ebx, diff
+            mov edi, row
+            mov esi, prev_row
+            // PRIME the pump (load the first Raw(x-bpp) data set
+            movq mm1, [edi+ebx-8]
+            pxor mm0, mm0
+dpth6lp:
+            // Must shift to position Raw(x-bpp) data
+            psrlq mm1, ShiftRem
+            // Do first set of 4 bytes
+            movq mm3, [esi+ebx-8]      // read c=Prior(x-bpp) bytes
+            punpcklbw mm1, mm0      // Unpack Low bytes of a
+            movq mm2, [esi + ebx]   // load b=Prior(x)
+            punpcklbw mm2, mm0      // Unpack Low bytes of b
+            // Must shift to position Prior(x-bpp) data
+            psrlq mm3, ShiftRem
+            // pav = p - a = (a + b - c) - a = b - c
+            movq mm4, mm2
+            punpcklbw mm3, mm0      // Unpack Low bytes of c
+            // pbv = p - b = (a + b - c) - b = a - c
+            movq mm5, mm1
+            psubw mm4, mm3
+            pxor mm7, mm7
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+            movq mm6, mm4
+            psubw mm5, mm3
+            // pa = abs(p-a) = abs(pav)
+            // pb = abs(p-b) = abs(pbv)
+            // pc = abs(p-c) = abs(pcv)
+            pcmpgtw mm0, mm4    // Create mask pav bytes < 0
+            paddw mm6, mm5
+            pand mm0, mm4       // Only pav bytes < 0 in mm7
+            pcmpgtw mm7, mm5    // Create mask pbv bytes < 0
+            psubw mm4, mm0
+            pand mm7, mm5       // Only pbv bytes < 0 in mm0
+            psubw mm4, mm0
+            psubw mm5, mm7
+            pxor mm0, mm0
+            pcmpgtw mm0, mm6    // Create mask pcv bytes < 0
+            pand mm0, mm6       // Only pav bytes < 0 in mm7
+            psubw mm5, mm7
+            psubw mm6, mm0
+            //  test pa <= pb
+            movq mm7, mm4
+            psubw mm6, mm0
+            pcmpgtw mm7, mm5    // pa > pb?
+            movq mm0, mm7
+            // use mm7 mask to merge pa & pb
+            pand mm5, mm7
+            // use mm0 mask copy to merge a & b
+            pand mm2, mm0
+            pandn mm7, mm4
+            pandn mm0, mm1
+            paddw mm7, mm5
+            paddw mm0, mm2
+            //  test  ((pa <= pb)? pa:pb) <= pc
+            pcmpgtw mm7, mm6    // pab > pc?
+            pxor mm1, mm1
+            pand mm3, mm7
+            pandn mm7, mm0
+            paddw mm7, mm3
+            pxor mm0, mm0
+            packuswb mm7, mm1
+            movq mm3, [esi + ebx - 8]  // load c=Prior(x-bpp)
+            pand mm7, ActiveMask
+            psrlq mm3, ShiftRem
+            movq mm2, [esi + ebx]      // load b=Prior(x) step 1
+            paddb mm7, [edi + ebx]     // add Paeth predictor with Raw(x)
+            movq mm6, mm2
+            movq [edi + ebx], mm7      // write back updated value
+            movq mm1, [edi+ebx-8]
+            psllq mm6, ShiftBpp
+            movq mm5, mm7
+            psrlq mm1, ShiftRem
+            por mm3, mm6
+            psllq mm5, ShiftBpp
+            punpckhbw mm3, mm0         // Unpack High bytes of c
+            por mm1, mm5
+            // Do second set of 4 bytes
+            punpckhbw mm2, mm0         // Unpack High bytes of b
+            punpckhbw mm1, mm0         // Unpack High bytes of a
+            // pav = p - a = (a + b - c) - a = b - c
+            movq mm4, mm2
+            // pbv = p - b = (a + b - c) - b = a - c
+            movq mm5, mm1
+            psubw mm4, mm3
+            pxor mm7, mm7
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+            movq mm6, mm4
+            psubw mm5, mm3
+            // pa = abs(p-a) = abs(pav)
+            // pb = abs(p-b) = abs(pbv)
+            // pc = abs(p-c) = abs(pcv)
+            pcmpgtw mm0, mm4       // Create mask pav bytes < 0
+            paddw mm6, mm5
+            pand mm0, mm4          // Only pav bytes < 0 in mm7
+            pcmpgtw mm7, mm5       // Create mask pbv bytes < 0
+            psubw mm4, mm0
+            pand mm7, mm5          // Only pbv bytes < 0 in mm0
+            psubw mm4, mm0
+            psubw mm5, mm7
+            pxor mm0, mm0
+            pcmpgtw mm0, mm6       // Create mask pcv bytes < 0
+            pand mm0, mm6          // Only pav bytes < 0 in mm7
+            psubw mm5, mm7
+            psubw mm6, mm0
+            //  test pa <= pb
+            movq mm7, mm4
+            psubw mm6, mm0
+            pcmpgtw mm7, mm5       // pa > pb?
+            movq mm0, mm7
+            // use mm7 mask to merge pa & pb
+            pand mm5, mm7
+            // use mm0 mask copy to merge a & b
+            pand mm2, mm0
+            pandn mm7, mm4
+            pandn mm0, mm1
+            paddw mm7, mm5
+            paddw mm0, mm2
+            //  test  ((pa <= pb)? pa:pb) <= pc
+            pcmpgtw mm7, mm6           // pab > pc?
+            pxor mm1, mm1
+            pand mm3, mm7
+            pandn mm7, mm0
+            pxor mm1, mm1
+            paddw mm7, mm3
+            pxor mm0, mm0
+            // Step ex to next set of 8 bytes and repeat loop til done
+            add ebx, 8
+            packuswb mm1, mm7
+            paddb mm1, [edi + ebx - 8]     // add Paeth predictor with Raw(x)
+            cmp ebx, MMXLength
+            movq [edi + ebx - 8], mm1      // write back updated value
+                                // mm1 will be used as Raw(x-bpp) next loop
+            jb dpth6lp
+         } // end _asm block
+      }
+      break;
+
+      case 4:
+      {
+         ActiveMask.use  = 0x00000000ffffffff;
+         _asm {
+            mov ebx, diff
+            mov edi, row
+            mov esi, prev_row
+            pxor mm0, mm0
+            // PRIME the pump (load the first Raw(x-bpp) data set
+            movq mm1, [edi+ebx-8]    // Only time should need to read
+                                     //  a=Raw(x-bpp) bytes
+dpth4lp:
+            // Do first set of 4 bytes
+            movq mm3, [esi+ebx-8]    // read c=Prior(x-bpp) bytes
+            punpckhbw mm1, mm0       // Unpack Low bytes of a
+            movq mm2, [esi + ebx]    // load b=Prior(x)
+            punpcklbw mm2, mm0       // Unpack High bytes of b
+            // pav = p - a = (a + b - c) - a = b - c
+            movq mm4, mm2
+            punpckhbw mm3, mm0       // Unpack High bytes of c
+            // pbv = p - b = (a + b - c) - b = a - c
+            movq mm5, mm1
+            psubw mm4, mm3
+            pxor mm7, mm7
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+            movq mm6, mm4
+            psubw mm5, mm3
+            // pa = abs(p-a) = abs(pav)
+            // pb = abs(p-b) = abs(pbv)
+            // pc = abs(p-c) = abs(pcv)
+            pcmpgtw mm0, mm4       // Create mask pav bytes < 0
+            paddw mm6, mm5
+            pand mm0, mm4          // Only pav bytes < 0 in mm7
+            pcmpgtw mm7, mm5       // Create mask pbv bytes < 0
+            psubw mm4, mm0
+            pand mm7, mm5          // Only pbv bytes < 0 in mm0
+            psubw mm4, mm0
+            psubw mm5, mm7
+            pxor mm0, mm0
+            pcmpgtw mm0, mm6       // Create mask pcv bytes < 0
+            pand mm0, mm6          // Only pav bytes < 0 in mm7
+            psubw mm5, mm7
+            psubw mm6, mm0
+            //  test pa <= pb
+            movq mm7, mm4
+            psubw mm6, mm0
+            pcmpgtw mm7, mm5       // pa > pb?
+            movq mm0, mm7
+            // use mm7 mask to merge pa & pb
+            pand mm5, mm7
+            // use mm0 mask copy to merge a & b
+            pand mm2, mm0
+            pandn mm7, mm4
+            pandn mm0, mm1
+            paddw mm7, mm5
+            paddw mm0, mm2
+            //  test  ((pa <= pb)? pa:pb) <= pc
+            pcmpgtw mm7, mm6       // pab > pc?
+            pxor mm1, mm1
+            pand mm3, mm7
+            pandn mm7, mm0
+            paddw mm7, mm3
+            pxor mm0, mm0
+            packuswb mm7, mm1
+            movq mm3, [esi + ebx]      // load c=Prior(x-bpp)
+            pand mm7, ActiveMask
+            movq mm2, mm3              // load b=Prior(x) step 1
+            paddb mm7, [edi + ebx]     // add Paeth predictor with Raw(x)
+            punpcklbw mm3, mm0         // Unpack High bytes of c
+            movq [edi + ebx], mm7      // write back updated value
+            movq mm1, mm7              // Now mm1 will be used as Raw(x-bpp)
+            // Do second set of 4 bytes
+            punpckhbw mm2, mm0         // Unpack Low bytes of b
+            punpcklbw mm1, mm0         // Unpack Low bytes of a
+            // pav = p - a = (a + b - c) - a = b - c
+            movq mm4, mm2
+            // pbv = p - b = (a + b - c) - b = a - c
+            movq mm5, mm1
+            psubw mm4, mm3
+            pxor mm7, mm7
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+            movq mm6, mm4
+            psubw mm5, mm3
+            // pa = abs(p-a) = abs(pav)
+            // pb = abs(p-b) = abs(pbv)
+            // pc = abs(p-c) = abs(pcv)
+            pcmpgtw mm0, mm4       // Create mask pav bytes < 0
+            paddw mm6, mm5
+            pand mm0, mm4          // Only pav bytes < 0 in mm7
+            pcmpgtw mm7, mm5       // Create mask pbv bytes < 0
+            psubw mm4, mm0
+            pand mm7, mm5          // Only pbv bytes < 0 in mm0
+            psubw mm4, mm0
+            psubw mm5, mm7
+            pxor mm0, mm0
+            pcmpgtw mm0, mm6       // Create mask pcv bytes < 0
+            pand mm0, mm6          // Only pav bytes < 0 in mm7
+            psubw mm5, mm7
+            psubw mm6, mm0
+            //  test pa <= pb
+            movq mm7, mm4
+            psubw mm6, mm0
+            pcmpgtw mm7, mm5       // pa > pb?
+            movq mm0, mm7
+            // use mm7 mask to merge pa & pb
+            pand mm5, mm7
+            // use mm0 mask copy to merge a & b
+            pand mm2, mm0
+            pandn mm7, mm4
+            pandn mm0, mm1
+            paddw mm7, mm5
+            paddw mm0, mm2
+            //  test  ((pa <= pb)? pa:pb) <= pc
+            pcmpgtw mm7, mm6       // pab > pc?
+            pxor mm1, mm1
+            pand mm3, mm7
+            pandn mm7, mm0
+            pxor mm1, mm1
+            paddw mm7, mm3
+            pxor mm0, mm0
+            // Step ex to next set of 8 bytes and repeat loop til done
+            add ebx, 8
+            packuswb mm1, mm7
+            paddb mm1, [edi + ebx - 8]     // add Paeth predictor with Raw(x)
+            cmp ebx, MMXLength
+            movq [edi + ebx - 8], mm1      // write back updated value
+                                // mm1 will be used as Raw(x-bpp) next loop
+            jb dpth4lp
+         } // end _asm block
+      }
+      break;
+      case 8:                          // bpp == 8
+      {
+         ActiveMask.use  = 0x00000000ffffffff;
+         _asm {
+            mov ebx, diff
+            mov edi, row
+            mov esi, prev_row
+            pxor mm0, mm0
+            // PRIME the pump (load the first Raw(x-bpp) data set
+            movq mm1, [edi+ebx-8]      // Only time should need to read
+                                       //  a=Raw(x-bpp) bytes
+dpth8lp:
+            // Do first set of 4 bytes
+            movq mm3, [esi+ebx-8]      // read c=Prior(x-bpp) bytes
+            punpcklbw mm1, mm0         // Unpack Low bytes of a
+            movq mm2, [esi + ebx]      // load b=Prior(x)
+            punpcklbw mm2, mm0         // Unpack Low bytes of b
+            // pav = p - a = (a + b - c) - a = b - c
+            movq mm4, mm2
+            punpcklbw mm3, mm0         // Unpack Low bytes of c
+            // pbv = p - b = (a + b - c) - b = a - c
+            movq mm5, mm1
+            psubw mm4, mm3
+            pxor mm7, mm7
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+            movq mm6, mm4
+            psubw mm5, mm3
+            // pa = abs(p-a) = abs(pav)
+            // pb = abs(p-b) = abs(pbv)
+            // pc = abs(p-c) = abs(pcv)
+            pcmpgtw mm0, mm4       // Create mask pav bytes < 0
+            paddw mm6, mm5
+            pand mm0, mm4          // Only pav bytes < 0 in mm7
+            pcmpgtw mm7, mm5       // Create mask pbv bytes < 0
+            psubw mm4, mm0
+            pand mm7, mm5          // Only pbv bytes < 0 in mm0
+            psubw mm4, mm0
+            psubw mm5, mm7
+            pxor mm0, mm0
+            pcmpgtw mm0, mm6       // Create mask pcv bytes < 0
+            pand mm0, mm6          // Only pav bytes < 0 in mm7
+            psubw mm5, mm7
+            psubw mm6, mm0
+            //  test pa <= pb
+            movq mm7, mm4
+            psubw mm6, mm0
+            pcmpgtw mm7, mm5       // pa > pb?
+            movq mm0, mm7
+            // use mm7 mask to merge pa & pb
+            pand mm5, mm7
+            // use mm0 mask copy to merge a & b
+            pand mm2, mm0
+            pandn mm7, mm4
+            pandn mm0, mm1
+            paddw mm7, mm5
+            paddw mm0, mm2
+            //  test  ((pa <= pb)? pa:pb) <= pc
+            pcmpgtw mm7, mm6       // pab > pc?
+            pxor mm1, mm1
+            pand mm3, mm7
+            pandn mm7, mm0
+            paddw mm7, mm3
+            pxor mm0, mm0
+            packuswb mm7, mm1
+            movq mm3, [esi+ebx-8]    // read c=Prior(x-bpp) bytes
+            pand mm7, ActiveMask
+            movq mm2, [esi + ebx]    // load b=Prior(x)
+            paddb mm7, [edi + ebx]   // add Paeth predictor with Raw(x)
+            punpckhbw mm3, mm0       // Unpack High bytes of c
+            movq [edi + ebx], mm7    // write back updated value
+            movq mm1, [edi+ebx-8]    // read a=Raw(x-bpp) bytes
+
+            // Do second set of 4 bytes
+            punpckhbw mm2, mm0       // Unpack High bytes of b
+            punpckhbw mm1, mm0       // Unpack High bytes of a
+            // pav = p - a = (a + b - c) - a = b - c
+            movq mm4, mm2
+            // pbv = p - b = (a + b - c) - b = a - c
+            movq mm5, mm1
+            psubw mm4, mm3
+            pxor mm7, mm7
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+            movq mm6, mm4
+            psubw mm5, mm3
+            // pa = abs(p-a) = abs(pav)
+            // pb = abs(p-b) = abs(pbv)
+            // pc = abs(p-c) = abs(pcv)
+            pcmpgtw mm0, mm4       // Create mask pav bytes < 0
+            paddw mm6, mm5
+            pand mm0, mm4          // Only pav bytes < 0 in mm7
+            pcmpgtw mm7, mm5       // Create mask pbv bytes < 0
+            psubw mm4, mm0
+            pand mm7, mm5          // Only pbv bytes < 0 in mm0
+            psubw mm4, mm0
+            psubw mm5, mm7
+            pxor mm0, mm0
+            pcmpgtw mm0, mm6       // Create mask pcv bytes < 0
+            pand mm0, mm6          // Only pav bytes < 0 in mm7
+            psubw mm5, mm7
+            psubw mm6, mm0
+            //  test pa <= pb
+            movq mm7, mm4
+            psubw mm6, mm0
+            pcmpgtw mm7, mm5       // pa > pb?
+            movq mm0, mm7
+            // use mm7 mask to merge pa & pb
+            pand mm5, mm7
+            // use mm0 mask copy to merge a & b
+            pand mm2, mm0
+            pandn mm7, mm4
+            pandn mm0, mm1
+            paddw mm7, mm5
+            paddw mm0, mm2
+            //  test  ((pa <= pb)? pa:pb) <= pc
+            pcmpgtw mm7, mm6       // pab > pc?
+            pxor mm1, mm1
+            pand mm3, mm7
+            pandn mm7, mm0
+            pxor mm1, mm1
+            paddw mm7, mm3
+            pxor mm0, mm0
+            // Step ex to next set of 8 bytes and repeat loop til done
+            add ebx, 8
+            packuswb mm1, mm7
+            paddb mm1, [edi + ebx - 8]     // add Paeth predictor with Raw(x)
+            cmp ebx, MMXLength
+            movq [edi + ebx - 8], mm1      // write back updated value
+                            // mm1 will be used as Raw(x-bpp) next loop
+            jb dpth8lp
+         } // end _asm block
+      }
+      break;
+
+      case 1:                // bpp = 1
+      case 2:                // bpp = 2
+      default:               // bpp > 8
+      {
+         _asm {
+            mov ebx, diff
+            cmp ebx, FullLength
+            jnb dpthdend
+            mov edi, row
+            mov esi, prev_row
+            // Do Paeth decode for remaining bytes
+            mov edx, ebx
+            xor ecx, ecx        // zero ecx before using cl & cx in loop below
+            sub edx, bpp        // Set edx = ebx - bpp
+dpthdlp:
+            xor eax, eax
+            // pav = p - a = (a + b - c) - a = b - c
+            mov al, [esi + ebx]        // load Prior(x) into al
+            mov cl, [esi + edx]        // load Prior(x-bpp) into cl
+            sub eax, ecx                 // subtract Prior(x-bpp)
+            mov patemp, eax                 // Save pav for later use
+            xor eax, eax
+            // pbv = p - b = (a + b - c) - b = a - c
+            mov al, [edi + edx]        // load Raw(x-bpp) into al
+            sub eax, ecx                 // subtract Prior(x-bpp)
+            mov ecx, eax
+            // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+            add eax, patemp                 // pcv = pav + pbv
+            // pc = abs(pcv)
+            test eax, 0x80000000
+            jz dpthdpca
+            neg eax                     // reverse sign of neg values
+dpthdpca:
+            mov pctemp, eax             // save pc for later use
+            // pb = abs(pbv)
+            test ecx, 0x80000000
+            jz dpthdpba
+            neg ecx                     // reverse sign of neg values
+dpthdpba:
+            mov pbtemp, ecx             // save pb for later use
+            // pa = abs(pav)
+            mov eax, patemp
+            test eax, 0x80000000
+            jz dpthdpaa
+            neg eax                     // reverse sign of neg values
+dpthdpaa:
+            mov patemp, eax             // save pa for later use
+            // test if pa <= pb
+            cmp eax, ecx
+            jna dpthdabb
+            // pa > pb; now test if pb <= pc
+            cmp ecx, pctemp
+            jna dpthdbbc
+            // pb > pc; Raw(x) = Paeth(x) + Prior(x-bpp)
+            mov cl, [esi + edx]  // load Prior(x-bpp) into cl
+            jmp dpthdpaeth
+dpthdbbc:
+            // pb <= pc; Raw(x) = Paeth(x) + Prior(x)
+            mov cl, [esi + ebx]        // load Prior(x) into cl
+            jmp dpthdpaeth
+dpthdabb:
+            // pa <= pb; now test if pa <= pc
+            cmp eax, pctemp
+            jna dpthdabc
+            // pa > pc; Raw(x) = Paeth(x) + Prior(x-bpp)
+            mov cl, [esi + edx]  // load Prior(x-bpp) into cl
+            jmp dpthdpaeth
+dpthdabc:
+            // pa <= pc; Raw(x) = Paeth(x) + Raw(x-bpp)
+            mov cl, [edi + edx]  // load Raw(x-bpp) into cl
+dpthdpaeth:
+            inc ebx
+            inc edx
+            // Raw(x) = (Paeth(x) + Paeth_Predictor( a, b, c )) mod 256
+            add [edi + ebx - 1], cl
+            cmp ebx, FullLength
+            jb dpthdlp
+dpthdend:
+         } // end _asm block
+      }
+      return;                   // No need to go further with this one
+   }                         // end switch ( bpp )
+   _asm
+   {
+         // MMX acceleration complete now do clean-up
+         // Check if any remaining bytes left to decode
+         mov ebx, MMXLength
+         cmp ebx, FullLength
+         jnb dpthend
+         mov edi, row
+         mov esi, prev_row
+         // Do Paeth decode for remaining bytes
+         mov edx, ebx
+         xor ecx, ecx         // zero ecx before using cl & cx in loop below
+         sub edx, bpp         // Set edx = ebx - bpp
+dpthlp2:
+         xor eax, eax
+         // pav = p - a = (a + b - c) - a = b - c
+         mov al, [esi + ebx]  // load Prior(x) into al
+         mov cl, [esi + edx]  // load Prior(x-bpp) into cl
+         sub eax, ecx         // subtract Prior(x-bpp)
+         mov patemp, eax      // Save pav for later use
+         xor eax, eax
+         // pbv = p - b = (a + b - c) - b = a - c
+         mov al, [edi + edx]  // load Raw(x-bpp) into al
+         sub eax, ecx         // subtract Prior(x-bpp)
+         mov ecx, eax
+         // pcv = p - c = (a + b - c) -c = (a - c) + (b - c) = pav + pbv
+         add eax, patemp      // pcv = pav + pbv
+         // pc = abs(pcv)
+         test eax, 0x80000000
+         jz dpthpca2
+         neg eax              // reverse sign of neg values
+dpthpca2:
+         mov pctemp, eax      // save pc for later use
+         // pb = abs(pbv)
+         test ecx, 0x80000000
+         jz dpthpba2
+         neg ecx              // reverse sign of neg values
+dpthpba2:
+         mov pbtemp, ecx      // save pb for later use
+         // pa = abs(pav)
+         mov eax, patemp
+         test eax, 0x80000000
+         jz dpthpaa2
+         neg eax              // reverse sign of neg values
+dpthpaa2:
+         mov patemp, eax      // save pa for later use
+         // test if pa <= pb
+         cmp eax, ecx
+         jna dpthabb2
+         // pa > pb; now test if pb <= pc
+         cmp ecx, pctemp
+         jna dpthbbc2
+         // pb > pc; Raw(x) = Paeth(x) + Prior(x-bpp)
+         mov cl, [esi + edx]  // load Prior(x-bpp) into cl
+         jmp dpthpaeth2
+dpthbbc2:
+         // pb <= pc; Raw(x) = Paeth(x) + Prior(x)
+         mov cl, [esi + ebx]        // load Prior(x) into cl
+         jmp dpthpaeth2
+dpthabb2:
+         // pa <= pb; now test if pa <= pc
+         cmp eax, pctemp
+         jna dpthabc2
+         // pa > pc; Raw(x) = Paeth(x) + Prior(x-bpp)
+         mov cl, [esi + edx]  // load Prior(x-bpp) into cl
+         jmp dpthpaeth2
+dpthabc2:
+         // pa <= pc; Raw(x) = Paeth(x) + Raw(x-bpp)
+         mov cl, [edi + edx]  // load Raw(x-bpp) into cl
+dpthpaeth2:
+         inc ebx
+         inc edx
+         // Raw(x) = (Paeth(x) + Paeth_Predictor( a, b, c )) mod 256
+         add [edi + ebx - 1], cl
+         cmp ebx, FullLength
+         jb dpthlp2
+dpthend:
+         emms             // End MMX instructions; prep for possible FP instrs.
+   } // end _asm block
+}
+
+// Optimized code for PNG Sub filter decoder
+void /* PRIVATE */
+png_read_filter_row_mmx_sub(png_row_infop row_info, png_bytep row)
+{
+  // These variables are declared
+  // here to ensure alignment on 8-byte boundaries.
+  union uAll ActiveMask, ShiftBpp, ShiftRem;
+
+   //int test;
+   int bpp;
+   png_uint_32 FullLength;
+   png_uint_32 MMXLength;
+   int diff;
+
+   bpp = (row_info->pixel_depth + 7) >> 3; // Get # bytes per pixel
+   FullLength  = row_info->rowbytes - bpp; // # of bytes to filter
+   _asm {
+        mov edi, row
+        mov esi, edi               // lp = row
+        add edi, bpp               // rp = row + bpp
+        xor eax, eax
+        // get # of bytes to alignment
+        mov diff, edi               // take start of row
+        add diff, 0xf               // add 7 + 8 to incr past
+                                        // alignment boundary
+        xor ebx, ebx
+        and diff, 0xfffffff8        // mask to alignment boundary
+        sub diff, edi               // subtract from start ==> value
+                                        //  ebx at alignment
+        jz dsubgo
+        // fix alignment
+dsublp1:
+        mov al, [esi+ebx]
+        add [edi+ebx], al
+        inc ebx
+        cmp ebx, diff
+        jb dsublp1
+dsubgo:
+        mov ecx, FullLength
+        mov edx, ecx
+        sub edx, ebx                  // subtract alignment fix
+        and edx, 0x00000007           // calc bytes over mult of 8
+        sub ecx, edx                  // drop over bytes from length
+        mov MMXLength, ecx
+   } // end _asm block
+
+   // Now do the math for the rest of the row
+   switch ( bpp )
+   {
+        case 3:
+        {
+         ActiveMask.use  = 0x0000ffffff000000;
+         ShiftBpp.use = 24;       // == 3 * 8
+         ShiftRem.use  = 40;      // == 64 - 24
+         _asm {
+            mov edi, row
+            movq mm7, ActiveMask  // Load ActiveMask for 2nd active byte group
+            mov esi, edi              // lp = row
+            add edi, bpp          // rp = row + bpp
+            movq mm6, mm7
+            mov ebx, diff
+            psllq mm6, ShiftBpp   // Move mask in mm6 to cover 3rd active
+                                  // byte group
+            // PRIME the pump (load the first Raw(x-bpp) data set
+            movq mm1, [edi+ebx-8]
+dsub3lp:
+            psrlq mm1, ShiftRem   // Shift data for adding 1st bpp bytes
+                          // no need for mask; shift clears inactive bytes
+            // Add 1st active group
+            movq mm0, [edi+ebx]
+            paddb mm0, mm1
+            // Add 2nd active group
+            movq mm1, mm0         // mov updated Raws to mm1
+            psllq mm1, ShiftBpp   // shift data to position correctly
+            pand mm1, mm7         // mask to use only 2nd active group
+            paddb mm0, mm1
+            // Add 3rd active group
+            movq mm1, mm0         // mov updated Raws to mm1
+            psllq mm1, ShiftBpp   // shift data to position correctly
+            pand mm1, mm6         // mask to use only 3rd active group
+            add ebx, 8
+            paddb mm0, mm1
+            cmp ebx, MMXLength
+            movq [edi+ebx-8], mm0     // Write updated Raws back to array
+            // Prep for doing 1st add at top of loop
+            movq mm1, mm0
+            jb dsub3lp
+         } // end _asm block
+      }
+      break;
+
+      case 1:
+      {
+         // Placed here just in case this is a duplicate of the
+         // non-MMX code for the SUB filter in png_read_filter_row below
+         //
+         //         png_bytep rp;
+         //         png_bytep lp;
+         //         png_uint_32 i;
+         //         bpp = (row_info->pixel_depth + 7) >> 3;
+         //         for (i = (png_uint_32)bpp, rp = row + bpp, lp = row;
+         //            i < row_info->rowbytes; i++, rp++, lp++)
+         //      {
+         //            *rp = (png_byte)(((int)(*rp) + (int)(*lp)) & 0xff);
+         //      }
+         _asm {
+            mov ebx, diff
+            mov edi, row
+            cmp ebx, FullLength
+            jnb dsub1end
+            mov esi, edi          // lp = row
+            xor eax, eax
+            add edi, bpp      // rp = row + bpp
+dsub1lp:
+            mov al, [esi+ebx]
+            add [edi+ebx], al
+            inc ebx
+            cmp ebx, FullLength
+            jb dsub1lp
+dsub1end:
+         } // end _asm block
+      }
+      return;
+
+      case 6:
+      case 7:
+      case 4:
+      case 5:
+      {
+         ShiftBpp.use = bpp << 3;
+         ShiftRem.use = 64 - ShiftBpp.use;
+         _asm {
+            mov edi, row
+            mov ebx, diff
+            mov esi, edi               // lp = row
+            add edi, bpp           // rp = row + bpp
+            // PRIME the pump (load the first Raw(x-bpp) data set
+            movq mm1, [edi+ebx-8]
+dsub4lp:
+            psrlq mm1, ShiftRem // Shift data for adding 1st bpp bytes
+                          // no need for mask; shift clears inactive bytes
+            movq mm0, [edi+ebx]
+            paddb mm0, mm1
+            // Add 2nd active group
+            movq mm1, mm0          // mov updated Raws to mm1
+            psllq mm1, ShiftBpp    // shift data to position correctly
+                                   // there is no need for any mask
+                                   // since shift clears inactive bits/bytes
+            add ebx, 8
+            paddb mm0, mm1
+            cmp ebx, MMXLength
+            movq [edi+ebx-8], mm0
+            movq mm1, mm0          // Prep for doing 1st add at top of loop
+            jb dsub4lp
+         } // end _asm block
+      }
+      break;
+
+      case 2:
+      {
+         ActiveMask.use  = 0x00000000ffff0000;
+         ShiftBpp.use = 16;       // == 2 * 8
+         ShiftRem.use = 48;       // == 64 - 16
+         _asm {
+            movq mm7, ActiveMask  // Load ActiveMask for 2nd active byte group
+            mov ebx, diff
+            movq mm6, mm7
+            mov edi, row
+            psllq mm6, ShiftBpp     // Move mask in mm6 to cover 3rd active
+                                    //  byte group
+            mov esi, edi            // lp = row
+            movq mm5, mm6
+            add edi, bpp            // rp = row + bpp
+            psllq mm5, ShiftBpp     // Move mask in mm5 to cover 4th active
+                                    //  byte group
+            // PRIME the pump (load the first Raw(x-bpp) data set
+            movq mm1, [edi+ebx-8]
+dsub2lp:
+            // Add 1st active group
+            psrlq mm1, ShiftRem     // Shift data for adding 1st bpp bytes
+                                    // no need for mask; shift clears inactive
+                                    //  bytes
+            movq mm0, [edi+ebx]
+            paddb mm0, mm1
+            // Add 2nd active group
+            movq mm1, mm0           // mov updated Raws to mm1
+            psllq mm1, ShiftBpp     // shift data to position correctly
+            pand mm1, mm7           // mask to use only 2nd active group
+            paddb mm0, mm1
+            // Add 3rd active group
+            movq mm1, mm0           // mov updated Raws to mm1
+            psllq mm1, ShiftBpp     // shift data to position correctly
+            pand mm1, mm6           // mask to use only 3rd active group
+            paddb mm0, mm1
+            // Add 4th active group
+            movq mm1, mm0           // mov updated Raws to mm1
+            psllq mm1, ShiftBpp     // shift data to position correctly
+            pand mm1, mm5           // mask to use only 4th active group
+            add ebx, 8
+            paddb mm0, mm1
+            cmp ebx, MMXLength
+            movq [edi+ebx-8], mm0   // Write updated Raws back to array
+            movq mm1, mm0           // Prep for doing 1st add at top of loop
+            jb dsub2lp
+         } // end _asm block
+      }
+      break;
+      case 8:
+      {
+         _asm {
+            mov edi, row
+            mov ebx, diff
+            mov esi, edi            // lp = row
+            add edi, bpp            // rp = row + bpp
+            mov ecx, MMXLength
+            movq mm7, [edi+ebx-8]   // PRIME the pump (load the first
+                                    // Raw(x-bpp) data set
+            and ecx, 0x0000003f     // calc bytes over mult of 64
+dsub8lp:
+            movq mm0, [edi+ebx]     // Load Sub(x) for 1st 8 bytes
+            paddb mm0, mm7
+            movq mm1, [edi+ebx+8]   // Load Sub(x) for 2nd 8 bytes
+            movq [edi+ebx], mm0    // Write Raw(x) for 1st 8 bytes
+                                   // Now mm0 will be used as Raw(x-bpp) for
+                                   // the 2nd group of 8 bytes.  This will be
+                                   // repeated for each group of 8 bytes with
+                                   // the 8th group being used as the Raw(x-bpp)
+                                   // for the 1st group of the next loop.
+            paddb mm1, mm0
+            movq mm2, [edi+ebx+16]  // Load Sub(x) for 3rd 8 bytes
+            movq [edi+ebx+8], mm1   // Write Raw(x) for 2nd 8 bytes
+            paddb mm2, mm1
+            movq mm3, [edi+ebx+24]  // Load Sub(x) for 4th 8 bytes
+            movq [edi+ebx+16], mm2  // Write Raw(x) for 3rd 8 bytes
+            paddb mm3, mm2
+            movq mm4, [edi+ebx+32]  // Load Sub(x) for 5th 8 bytes
+            movq [edi+ebx+24], mm3  // Write Raw(x) for 4th 8 bytes
+            paddb mm4, mm3
+            movq mm5, [edi+ebx+40]  // Load Sub(x) for 6th 8 bytes
+            movq [edi+ebx+32], mm4  // Write Raw(x) for 5th 8 bytes
+            paddb mm5, mm4
+            movq mm6, [edi+ebx+48]  // Load Sub(x) for 7th 8 bytes
+            movq [edi+ebx+40], mm5  // Write Raw(x) for 6th 8 bytes
+            paddb mm6, mm5
+            movq mm7, [edi+ebx+56]  // Load Sub(x) for 8th 8 bytes
+            movq [edi+ebx+48], mm6  // Write Raw(x) for 7th 8 bytes
+            add ebx, 64
+            paddb mm7, mm6
+            cmp ebx, ecx
+            movq [edi+ebx-8], mm7   // Write Raw(x) for 8th 8 bytes
+            jb dsub8lp
+            cmp ebx, MMXLength
+            jnb dsub8lt8
+dsub8lpA:
+            movq mm0, [edi+ebx]
+            add ebx, 8
+            paddb mm0, mm7
+            cmp ebx, MMXLength
+            movq [edi+ebx-8], mm0   // use -8 to offset early add to ebx
+            movq mm7, mm0           // Move calculated Raw(x) data to mm1 to
+                                    // be the new Raw(x-bpp) for the next loop
+            jb dsub8lpA
+dsub8lt8:
+         } // end _asm block
+      }
+      break;
+
+      default:                // bpp greater than 8 bytes
+      {
+         _asm {
+            mov ebx, diff
+            mov edi, row
+            mov esi, edi           // lp = row
+            add edi, bpp           // rp = row + bpp
+dsubAlp:
+            movq mm0, [edi+ebx]
+            movq mm1, [esi+ebx]
+            add ebx, 8
+            paddb mm0, mm1
+            cmp ebx, MMXLength
+            movq [edi+ebx-8], mm0  // mov does not affect flags; -8 to offset
+                                   //  add ebx
+            jb dsubAlp
+         } // end _asm block
+      }
+      break;
+
+   } // end switch ( bpp )
+
+   _asm {
+        mov ebx, MMXLength
+        mov edi, row
+        cmp ebx, FullLength
+        jnb dsubend
+        mov esi, edi               // lp = row
+        xor eax, eax
+        add edi, bpp               // rp = row + bpp
+dsublp2:
+        mov al, [esi+ebx]
+        add [edi+ebx], al
+        inc ebx
+        cmp ebx, FullLength
+        jb dsublp2
+dsubend:
+        emms             // End MMX instructions; prep for possible FP instrs.
+   } // end _asm block
+}
+
+// Optimized code for PNG Up filter decoder
+void /* PRIVATE */
+png_read_filter_row_mmx_up(png_row_infop row_info, png_bytep row,
+   png_bytep prev_row)
+{
+   png_uint_32 len;
+   len  = row_info->rowbytes;       // # of bytes to filter
+   _asm {
+      mov edi, row
+      // get # of bytes to alignment
+      mov ecx, edi
+      xor ebx, ebx
+      add ecx, 0x7
+      xor eax, eax
+      and ecx, 0xfffffff8
+      mov esi, prev_row
+      sub ecx, edi
+      jz dupgo
+      // fix alignment
+duplp1:
+      mov al, [edi+ebx]
+      add al, [esi+ebx]
+      inc ebx
+      cmp ebx, ecx
+      mov [edi + ebx-1], al  // mov does not affect flags; -1 to offset inc ebx
+      jb duplp1
+dupgo:
+      mov ecx, len
+      mov edx, ecx
+      sub edx, ebx                  // subtract alignment fix
+      and edx, 0x0000003f           // calc bytes over mult of 64
+      sub ecx, edx                  // drop over bytes from length
+      // Unrolled loop - use all MMX registers and interleave to reduce
+      // number of branch instructions (loops) and reduce partial stalls
+duploop:
+      movq mm1, [esi+ebx]
+      movq mm0, [edi+ebx]
+      movq mm3, [esi+ebx+8]
+      paddb mm0, mm1
+      movq mm2, [edi+ebx+8]
+      movq [edi+ebx], mm0
+      paddb mm2, mm3
+      movq mm5, [esi+ebx+16]
+      movq [edi+ebx+8], mm2
+      movq mm4, [edi+ebx+16]
+      movq mm7, [esi+ebx+24]
+      paddb mm4, mm5
+      movq mm6, [edi+ebx+24]
+      movq [edi+ebx+16], mm4
+      paddb mm6, mm7
+      movq mm1, [esi+ebx+32]
+      movq [edi+ebx+24], mm6
+      movq mm0, [edi+ebx+32]
+      movq mm3, [esi+ebx+40]
+      paddb mm0, mm1
+      movq mm2, [edi+ebx+40]
+      movq [edi+ebx+32], mm0
+      paddb mm2, mm3
+      movq mm5, [esi+ebx+48]
+      movq [edi+ebx+40], mm2
+      movq mm4, [edi+ebx+48]
+      movq mm7, [esi+ebx+56]
+      paddb mm4, mm5
+      movq mm6, [edi+ebx+56]
+      movq [edi+ebx+48], mm4
+      add ebx, 64
+      paddb mm6, mm7
+      cmp ebx, ecx
+      movq [edi+ebx-8], mm6 // (+56)movq does not affect flags;
+                                     // -8 to offset add ebx
+      jb duploop
+
+      cmp edx, 0                     // Test for bytes over mult of 64
+      jz dupend
+
+
+      // 2 lines added by lcreeve at netins.net
+      // (mail 11 Jul 98 in png-implement list)
+      cmp edx, 8 //test for less than 8 bytes
+      jb duplt8
+
+
+      add ecx, edx
+      and edx, 0x00000007           // calc bytes over mult of 8
+      sub ecx, edx                  // drop over bytes from length
+      jz duplt8
+      // Loop using MMX registers mm0 & mm1 to update 8 bytes simultaneously
+duplpA:
+      movq mm1, [esi+ebx]
+      movq mm0, [edi+ebx]
+      add ebx, 8
+      paddb mm0, mm1
+      cmp ebx, ecx
+      movq [edi+ebx-8], mm0 // movq does not affect flags; -8 to offset add ebx
+      jb duplpA
+      cmp edx, 0            // Test for bytes over mult of 8
+      jz dupend
+duplt8:
+      xor eax, eax
+      add ecx, edx          // move over byte count into counter
+      // Loop using x86 registers to update remaining bytes
+duplp2:
+      mov al, [edi + ebx]
+      add al, [esi + ebx]
+      inc ebx
+      cmp ebx, ecx
+      mov [edi + ebx-1], al // mov does not affect flags; -1 to offset inc ebx
+      jb duplp2
+dupend:
+      // Conversion of filtered row completed
+      emms          // End MMX instructions; prep for possible FP instrs.
+   } // end _asm block
+}
+
+
+// Optimized png_read_filter_row routines
+void /* PRIVATE */
+png_read_filter_row(png_structp png_ptr, png_row_infop row_info, png_bytep
+   row, png_bytep prev_row, int filter)
+{
+#ifdef PNG_DEBUG
+   char filnm[10];
+#endif
+
+   if (mmx_supported == 2) {
+#if !defined(PNG_1_0_X)
+       /* this should have happened in png_init_mmx_flags() already */
+       png_warning(png_ptr, "asm_flags may not have been initialized");
+#endif
+       png_mmx_support();
+   }
+
+#ifdef PNG_DEBUG
+   png_debug(1, "in png_read_filter_row\n");
+   switch (filter)
+   {
+      case 0: png_snprintf(filnm, 10, "none");
+         break;
+#if !defined(PNG_1_0_X)
+      case 1: png_snprintf(filnm, 10, "sub-%s",
+        (png_ptr->asm_flags & PNG_ASM_FLAG_MMX_READ_FILTER_SUB)? "MMX" : "x86");
+         break;
+      case 2: png_snprintf(filnm, 10, "up-%s",
+        (png_ptr->asm_flags & PNG_ASM_FLAG_MMX_READ_FILTER_UP)? "MMX" : "x86");
+         break;
+      case 3: png_snprintf(filnm, 10, "avg-%s",
+        (png_ptr->asm_flags & PNG_ASM_FLAG_MMX_READ_FILTER_AVG)? "MMX" : "x86");
+         break;
+      case 4: png_snprintf(filnm, 10, "Paeth-%s",
+        (png_ptr->asm_flags & PNG_ASM_FLAG_MMX_READ_FILTER_PAETH)? "MMX":"x86");
+         break;
+#else
+      case 1: png_snprintf(filnm, 10, "sub");
+         break;
+      case 2: png_snprintf(filnm, 10, "up");
+         break;
+      case 3: png_snprintf(filnm, 10, "avg");
+         break;
+      case 4: png_snprintf(filnm, 10, "Paeth");
+         break;
+#endif
+      default: png_snprintf(filnm, 10, "unknw");
+         break;
+   }
+   png_debug2(0,"row=%5d, %s, ", png_ptr->row_number, filnm);
+   png_debug2(0, "pd=%2d, b=%d, ", (int)row_info->pixel_depth,
+      (int)((row_info->pixel_depth + 7) >> 3));
+   png_debug1(0,"len=%8d, ", row_info->rowbytes);
+#endif /* PNG_DEBUG */
+
+   switch (filter)
+   {
+      case PNG_FILTER_VALUE_NONE:
+         break;
+
+      case PNG_FILTER_VALUE_SUB:
+      {
+#if !defined(PNG_1_0_X)
+         if ((png_ptr->asm_flags & PNG_ASM_FLAG_MMX_READ_FILTER_SUB) &&
+             (row_info->pixel_depth >= png_ptr->mmx_bitdepth_threshold) &&
+             (row_info->rowbytes >= png_ptr->mmx_rowbytes_threshold))
+#else
+         if (mmx_supported)
+#endif
+         {
+            png_read_filter_row_mmx_sub(row_info, row);
+         }
+         else
+         {
+            png_uint_32 i;
+            png_uint_32 istop = row_info->rowbytes;
+            png_uint_32 bpp = (row_info->pixel_depth + 7) >> 3;
+            png_bytep rp = row + bpp;
+            png_bytep lp = row;
+
+            for (i = bpp; i < istop; i++)
+            {
+               *rp = (png_byte)(((int)(*rp) + (int)(*lp++)) & 0xff);
+               rp++;
+            }
+         }
+         break;
+      }
+
+      case PNG_FILTER_VALUE_UP:
+      {
+#if !defined(PNG_1_0_X)
+         if ((png_ptr->asm_flags & PNG_ASM_FLAG_MMX_READ_FILTER_UP) &&
+             (row_info->pixel_depth >= png_ptr->mmx_bitdepth_threshold) &&
+             (row_info->rowbytes >= png_ptr->mmx_rowbytes_threshold))
+#else
+         if (mmx_supported)
+#endif
+         {
+            png_read_filter_row_mmx_up(row_info, row, prev_row);
+         }
+         else
+         {
+            png_uint_32 i;
+            png_uint_32 istop = row_info->rowbytes;
+            png_bytep rp = row;
+            png_bytep pp = prev_row;
+
+            for (i = 0; i < istop; ++i)
+            {
+               *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
+               rp++;
+            }
+         }
+         break;
+      }
+
+      case PNG_FILTER_VALUE_AVG:
+      {
+#if !defined(PNG_1_0_X)
+         if ((png_ptr->asm_flags & PNG_ASM_FLAG_MMX_READ_FILTER_AVG) &&
+             (row_info->pixel_depth >= png_ptr->mmx_bitdepth_threshold) &&
+             (row_info->rowbytes >= png_ptr->mmx_rowbytes_threshold))
+#else
+         if (mmx_supported)
+#endif
+         {
+            png_read_filter_row_mmx_avg(row_info, row, prev_row);
+         }
+         else
+         {
+            png_uint_32 i;
+            png_bytep rp = row;
+            png_bytep pp = prev_row;
+            png_bytep lp = row;
+            png_uint_32 bpp = (row_info->pixel_depth + 7) >> 3;
+            png_uint_32 istop = row_info->rowbytes - bpp;
+
+            for (i = 0; i < bpp; i++)
+            {
+               *rp = (png_byte)(((int)(*rp) +
+                  ((int)(*pp++) >> 1)) & 0xff);
+               rp++;
+            }
+
+            for (i = 0; i < istop; i++)
+            {
+               *rp = (png_byte)(((int)(*rp) +
+                  ((int)(*pp++ + *lp++) >> 1)) & 0xff);
+               rp++;
+            }
+         }
+         break;
+      }
+
+      case PNG_FILTER_VALUE_PAETH:
+      {
+#if !defined(PNG_1_0_X)
+         if ((png_ptr->asm_flags & PNG_ASM_FLAG_MMX_READ_FILTER_PAETH) &&
+             (row_info->pixel_depth >= png_ptr->mmx_bitdepth_threshold) &&
+             (row_info->rowbytes >= png_ptr->mmx_rowbytes_threshold))
+#else
+         if (mmx_supported)
+#endif
+         {
+            png_read_filter_row_mmx_paeth(row_info, row, prev_row);
+         }
+         else
+         {
+            png_uint_32 i;
+            png_bytep rp = row;
+            png_bytep pp = prev_row;
+            png_bytep lp = row;
+            png_bytep cp = prev_row;
+            png_uint_32 bpp = (row_info->pixel_depth + 7) >> 3;
+            png_uint_32 istop=row_info->rowbytes - bpp;
+
+            for (i = 0; i < bpp; i++)
+            {
+               *rp = (png_byte)(((int)(*rp) + (int)(*pp++)) & 0xff);
+               rp++;
+            }
+
+            for (i = 0; i < istop; i++)   // use leftover rp,pp
+            {
+               int a, b, c, pa, pb, pc, p;
+
+               a = *lp++;
+               b = *pp++;
+               c = *cp++;
+
+               p = b - c;
+               pc = a - c;
+
+#ifdef PNG_USE_ABS
+               pa = abs(p);
+               pb = abs(pc);
+               pc = abs(p + pc);
+#else
+               pa = p < 0 ? -p : p;
+               pb = pc < 0 ? -pc : pc;
+               pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+#endif
+
+               /*
+                  if (pa <= pb && pa <= pc)
+                     p = a;
+                  else if (pb <= pc)
+                     p = b;
+                  else
+                     p = c;
+                */
+
+               p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
+
+               *rp = (png_byte)(((int)(*rp) + p) & 0xff);
+               rp++;
+            }
+         }
+         break;
+      }
+
+      default:
+         png_warning(png_ptr, "Ignoring bad row filter type");
+         *row=0;
+         break;
+   }
+}
+
+#endif /* PNG_MMX_CODE_SUPPORTED && PNG_USE_PNGVCRD */
diff --git a/distrib/libpng-1.2.19/pngwio.c b/distrib/libpng-1.2.19/pngwio.c
new file mode 100644
index 0000000..371a4fa
--- /dev/null
+++ b/distrib/libpng-1.2.19/pngwio.c
@@ -0,0 +1,234 @@
+
+/* pngwio.c - functions for data output
+ *
+ * Last changed in libpng 1.2.13 November 13, 2006
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1998-2006 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ *
+ * This file provides a location for all output.  Users who need
+ * special handling are expected to write functions that have the same
+ * arguments as these and perform similar functions, but that possibly
+ * use different output methods.  Note that you shouldn't change these
+ * functions, but rather write replacement functions and then change
+ * them at run time with png_set_write_fn(...).
+ */
+
+#define PNG_INTERNAL
+#include "png.h"
+#ifdef PNG_WRITE_SUPPORTED
+
+/* Write the data to whatever output you are using.  The default routine
+   writes to a file pointer.  Note that this routine sometimes gets called
+   with very small lengths, so you should implement some kind of simple
+   buffering if you are using unbuffered writes.  This should never be asked
+   to write more than 64K on a 16 bit machine.  */
+
+void /* PRIVATE */
+png_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
+{
+   if (png_ptr->write_data_fn != NULL )
+      (*(png_ptr->write_data_fn))(png_ptr, data, length);
+   else
+      png_error(png_ptr, "Call to NULL write function");
+}
+
+#if !defined(PNG_NO_STDIO)
+/* This is the function that does the actual writing of data.  If you are
+   not writing to a standard C stream, you should create a replacement
+   write_data function and use it at run time with png_set_write_fn(), rather
+   than changing the library. */
+#ifndef USE_FAR_KEYWORD
+void PNGAPI
+png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
+{
+   png_uint_32 check;
+
+   if(png_ptr == NULL) return;
+#if defined(_WIN32_WCE)
+   if ( !WriteFile((HANDLE)(png_ptr->io_ptr), data, length, &check, NULL) )
+      check = 0;
+#else
+   check = fwrite(data, 1, length, (png_FILE_p)(png_ptr->io_ptr));
+#endif
+   if (check != length)
+      png_error(png_ptr, "Write Error");
+}
+#else
+/* this is the model-independent version. Since the standard I/O library
+   can't handle far buffers in the medium and small models, we have to copy
+   the data.
+*/
+
+#define NEAR_BUF_SIZE 1024
+#define MIN(a,b) (a <= b ? a : b)
+
+void PNGAPI
+png_default_write_data(png_structp png_ptr, png_bytep data, png_size_t length)
+{
+   png_uint_32 check;
+   png_byte *near_data;  /* Needs to be "png_byte *" instead of "png_bytep" */
+   png_FILE_p io_ptr;
+
+   if(png_ptr == NULL) return;
+   /* Check if data really is near. If so, use usual code. */
+   near_data = (png_byte *)CVT_PTR_NOCHECK(data);
+   io_ptr = (png_FILE_p)CVT_PTR(png_ptr->io_ptr);
+   if ((png_bytep)near_data == data)
+   {
+#if defined(_WIN32_WCE)
+      if ( !WriteFile(io_ptr, near_data, length, &check, NULL) )
+         check = 0;
+#else
+      check = fwrite(near_data, 1, length, io_ptr);
+#endif
+   }
+   else
+   {
+      png_byte buf[NEAR_BUF_SIZE];
+      png_size_t written, remaining, err;
+      check = 0;
+      remaining = length;
+      do
+      {
+         written = MIN(NEAR_BUF_SIZE, remaining);
+         png_memcpy(buf, data, written); /* copy far buffer to near buffer */
+#if defined(_WIN32_WCE)
+         if ( !WriteFile(io_ptr, buf, written, &err, NULL) )
+            err = 0;
+#else
+         err = fwrite(buf, 1, written, io_ptr);
+#endif
+         if (err != written)
+            break;
+         else
+            check += err;
+         data += written;
+         remaining -= written;
+      }
+      while (remaining != 0);
+   }
+   if (check != length)
+      png_error(png_ptr, "Write Error");
+}
+
+#endif
+#endif
+
+/* This function is called to output any data pending writing (normally
+   to disk).  After png_flush is called, there should be no data pending
+   writing in any buffers. */
+#if defined(PNG_WRITE_FLUSH_SUPPORTED)
+void /* PRIVATE */
+png_flush(png_structp png_ptr)
+{
+   if (png_ptr->output_flush_fn != NULL)
+      (*(png_ptr->output_flush_fn))(png_ptr);
+}
+
+#if !defined(PNG_NO_STDIO)
+void PNGAPI
+png_default_flush(png_structp png_ptr)
+{
+#if !defined(_WIN32_WCE)
+   png_FILE_p io_ptr;
+#endif
+   if(png_ptr == NULL) return;
+#if !defined(_WIN32_WCE)
+   io_ptr = (png_FILE_p)CVT_PTR((png_ptr->io_ptr));
+   if (io_ptr != NULL)
+      fflush(io_ptr);
+#endif
+}
+#endif
+#endif
+
+/* This function allows the application to supply new output functions for
+   libpng if standard C streams aren't being used.
+
+   This function takes as its arguments:
+   png_ptr       - pointer to a png output data structure
+   io_ptr        - pointer to user supplied structure containing info about
+                   the output functions.  May be NULL.
+   write_data_fn - pointer to a new output function that takes as its
+                   arguments a pointer to a png_struct, a pointer to
+                   data to be written, and a 32-bit unsigned int that is
+                   the number of bytes to be written.  The new write
+                   function should call png_error(png_ptr, "Error msg")
+                   to exit and output any fatal error messages.
+   flush_data_fn - pointer to a new flush function that takes as its
+                   arguments a pointer to a png_struct.  After a call to
+                   the flush function, there should be no data in any buffers
+                   or pending transmission.  If the output method doesn't do
+                   any buffering of ouput, a function prototype must still be
+                   supplied although it doesn't have to do anything.  If
+                   PNG_WRITE_FLUSH_SUPPORTED is not defined at libpng compile
+                   time, output_flush_fn will be ignored, although it must be
+                   supplied for compatibility. */
+void PNGAPI
+png_set_write_fn(png_structp png_ptr, png_voidp io_ptr,
+   png_rw_ptr write_data_fn, png_flush_ptr output_flush_fn)
+{
+   if(png_ptr == NULL) return;
+   png_ptr->io_ptr = io_ptr;
+
+#if !defined(PNG_NO_STDIO)
+   if (write_data_fn != NULL)
+      png_ptr->write_data_fn = write_data_fn;
+   else
+      png_ptr->write_data_fn = png_default_write_data;
+#else
+   png_ptr->write_data_fn = write_data_fn;
+#endif
+
+#if defined(PNG_WRITE_FLUSH_SUPPORTED)
+#if !defined(PNG_NO_STDIO)
+   if (output_flush_fn != NULL)
+      png_ptr->output_flush_fn = output_flush_fn;
+   else
+      png_ptr->output_flush_fn = png_default_flush;
+#else
+   png_ptr->output_flush_fn = output_flush_fn;
+#endif
+#endif /* PNG_WRITE_FLUSH_SUPPORTED */
+
+   /* It is an error to read while writing a png file */
+   if (png_ptr->read_data_fn != NULL)
+   {
+      png_ptr->read_data_fn = NULL;
+      png_warning(png_ptr,
+         "Attempted to set both read_data_fn and write_data_fn in");
+      png_warning(png_ptr,
+         "the same structure.  Resetting read_data_fn to NULL.");
+   }
+}
+
+#if defined(USE_FAR_KEYWORD)
+#if defined(_MSC_VER)
+void *png_far_to_near(png_structp png_ptr,png_voidp ptr, int check)
+{
+   void *near_ptr;
+   void FAR *far_ptr;
+   FP_OFF(near_ptr) = FP_OFF(ptr);
+   far_ptr = (void FAR *)near_ptr;
+   if(check != 0)
+      if(FP_SEG(ptr) != FP_SEG(far_ptr))
+         png_error(png_ptr,"segment lost in conversion");
+   return(near_ptr);
+}
+#  else
+void *png_far_to_near(png_structp png_ptr,png_voidp ptr, int check)
+{
+   void *near_ptr;
+   void FAR *far_ptr;
+   near_ptr = (void FAR *)ptr;
+   far_ptr = (void FAR *)near_ptr;
+   if(check != 0)
+      if(far_ptr != ptr)
+         png_error(png_ptr,"segment lost in conversion");
+   return(near_ptr);
+}
+#   endif
+#   endif
+#endif /* PNG_WRITE_SUPPORTED */
diff --git a/distrib/libpng-1.2.19/pngwrite.c b/distrib/libpng-1.2.19/pngwrite.c
new file mode 100644
index 0000000..8d5b98a
--- /dev/null
+++ b/distrib/libpng-1.2.19/pngwrite.c
@@ -0,0 +1,1530 @@
+
+/* pngwrite.c - general routines to write a PNG file
+ *
+ * Last changed in libpng 1.2.15 January 5, 2007
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1998-2007 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ */
+
+/* get internal access to png.h */
+#define PNG_INTERNAL
+#include "png.h"
+#ifdef PNG_WRITE_SUPPORTED
+
+/* Writes all the PNG information.  This is the suggested way to use the
+ * library.  If you have a new chunk to add, make a function to write it,
+ * and put it in the correct location here.  If you want the chunk written
+ * after the image data, put it in png_write_end().  I strongly encourage
+ * you to supply a PNG_INFO_ flag, and check info_ptr->valid before writing
+ * the chunk, as that will keep the code from breaking if you want to just
+ * write a plain PNG file.  If you have long comments, I suggest writing
+ * them in png_write_end(), and compressing them.
+ */
+void PNGAPI
+png_write_info_before_PLTE(png_structp png_ptr, png_infop info_ptr)
+{
+   png_debug(1, "in png_write_info_before_PLTE\n");
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+   if (!(png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE))
+   {
+   png_write_sig(png_ptr); /* write PNG signature */
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
+   if((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE)&&(png_ptr->mng_features_permitted))
+   {
+      png_warning(png_ptr,"MNG features are not allowed in a PNG datastream");
+      png_ptr->mng_features_permitted=0;
+   }
+#endif
+   /* write IHDR information. */
+   png_write_IHDR(png_ptr, info_ptr->width, info_ptr->height,
+      info_ptr->bit_depth, info_ptr->color_type, info_ptr->compression_type,
+      info_ptr->filter_type,
+#if defined(PNG_WRITE_INTERLACING_SUPPORTED)
+      info_ptr->interlace_type);
+#else
+      0);
+#endif
+   /* the rest of these check to see if the valid field has the appropriate
+      flag set, and if it does, writes the chunk. */
+#if defined(PNG_WRITE_gAMA_SUPPORTED)
+   if (info_ptr->valid & PNG_INFO_gAMA)
+   {
+#  ifdef PNG_FLOATING_POINT_SUPPORTED
+      png_write_gAMA(png_ptr, info_ptr->gamma);
+#else
+#ifdef PNG_FIXED_POINT_SUPPORTED
+      png_write_gAMA_fixed(png_ptr, info_ptr->int_gamma);
+#  endif
+#endif
+   }
+#endif
+#if defined(PNG_WRITE_sRGB_SUPPORTED)
+   if (info_ptr->valid & PNG_INFO_sRGB)
+      png_write_sRGB(png_ptr, (int)info_ptr->srgb_intent);
+#endif
+#if defined(PNG_WRITE_iCCP_SUPPORTED)
+   if (info_ptr->valid & PNG_INFO_iCCP)
+      png_write_iCCP(png_ptr, info_ptr->iccp_name, PNG_COMPRESSION_TYPE_BASE,
+                     info_ptr->iccp_profile, (int)info_ptr->iccp_proflen);
+#endif
+#if defined(PNG_WRITE_sBIT_SUPPORTED)
+   if (info_ptr->valid & PNG_INFO_sBIT)
+      png_write_sBIT(png_ptr, &(info_ptr->sig_bit), info_ptr->color_type);
+#endif
+#if defined(PNG_WRITE_cHRM_SUPPORTED)
+   if (info_ptr->valid & PNG_INFO_cHRM)
+   {
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+      png_write_cHRM(png_ptr,
+         info_ptr->x_white, info_ptr->y_white,
+         info_ptr->x_red, info_ptr->y_red,
+         info_ptr->x_green, info_ptr->y_green,
+         info_ptr->x_blue, info_ptr->y_blue);
+#else
+#  ifdef PNG_FIXED_POINT_SUPPORTED
+      png_write_cHRM_fixed(png_ptr,
+         info_ptr->int_x_white, info_ptr->int_y_white,
+         info_ptr->int_x_red, info_ptr->int_y_red,
+         info_ptr->int_x_green, info_ptr->int_y_green,
+         info_ptr->int_x_blue, info_ptr->int_y_blue);
+#  endif
+#endif
+   }
+#endif
+#if defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED)
+   if (info_ptr->unknown_chunks_num)
+   {
+       png_unknown_chunk *up;
+
+       png_debug(5, "writing extra chunks\n");
+
+       for (up = info_ptr->unknown_chunks;
+            up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;
+            up++)
+       {
+         int keep=png_handle_as_unknown(png_ptr, up->name);
+         if (keep != PNG_HANDLE_CHUNK_NEVER &&
+            up->location && !(up->location & PNG_HAVE_PLTE) &&
+            !(up->location & PNG_HAVE_IDAT) &&
+            ((up->name[3] & 0x20) || keep == PNG_HANDLE_CHUNK_ALWAYS ||
+            (png_ptr->flags & PNG_FLAG_KEEP_UNSAFE_CHUNKS)))
+         {
+            png_write_chunk(png_ptr, up->name, up->data, up->size);
+         }
+       }
+   }
+#endif
+      png_ptr->mode |= PNG_WROTE_INFO_BEFORE_PLTE;
+   }
+}
+
+void PNGAPI
+png_write_info(png_structp png_ptr, png_infop info_ptr)
+{
+#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
+   int i;
+#endif
+
+   png_debug(1, "in png_write_info\n");
+
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+
+   png_write_info_before_PLTE(png_ptr, info_ptr);
+
+   if (info_ptr->valid & PNG_INFO_PLTE)
+      png_write_PLTE(png_ptr, info_ptr->palette,
+         (png_uint_32)info_ptr->num_palette);
+   else if (info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+      png_error(png_ptr, "Valid palette required for paletted images");
+
+#if defined(PNG_WRITE_tRNS_SUPPORTED)
+   if (info_ptr->valid & PNG_INFO_tRNS)
+      {
+#if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
+         /* invert the alpha channel (in tRNS) */
+         if ((png_ptr->transformations & PNG_INVERT_ALPHA) &&
+            info_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+         {
+            int j;
+            for (j=0; j<(int)info_ptr->num_trans; j++)
+               info_ptr->trans[j] = (png_byte)(255 - info_ptr->trans[j]);
+         }
+#endif
+      png_write_tRNS(png_ptr, info_ptr->trans, &(info_ptr->trans_values),
+         info_ptr->num_trans, info_ptr->color_type);
+      }
+#endif
+#if defined(PNG_WRITE_bKGD_SUPPORTED)
+   if (info_ptr->valid & PNG_INFO_bKGD)
+      png_write_bKGD(png_ptr, &(info_ptr->background), info_ptr->color_type);
+#endif
+#if defined(PNG_WRITE_hIST_SUPPORTED)
+   if (info_ptr->valid & PNG_INFO_hIST)
+      png_write_hIST(png_ptr, info_ptr->hist, info_ptr->num_palette);
+#endif
+#if defined(PNG_WRITE_oFFs_SUPPORTED)
+   if (info_ptr->valid & PNG_INFO_oFFs)
+      png_write_oFFs(png_ptr, info_ptr->x_offset, info_ptr->y_offset,
+         info_ptr->offset_unit_type);
+#endif
+#if defined(PNG_WRITE_pCAL_SUPPORTED)
+   if (info_ptr->valid & PNG_INFO_pCAL)
+      png_write_pCAL(png_ptr, info_ptr->pcal_purpose, info_ptr->pcal_X0,
+         info_ptr->pcal_X1, info_ptr->pcal_type, info_ptr->pcal_nparams,
+         info_ptr->pcal_units, info_ptr->pcal_params);
+#endif
+#if defined(PNG_WRITE_sCAL_SUPPORTED)
+   if (info_ptr->valid & PNG_INFO_sCAL)
+#if defined(PNG_FLOATING_POINT_SUPPORTED) && !defined(PNG_NO_STDIO)
+      png_write_sCAL(png_ptr, (int)info_ptr->scal_unit,
+          info_ptr->scal_pixel_width, info_ptr->scal_pixel_height);
+#else
+#ifdef PNG_FIXED_POINT_SUPPORTED
+      png_write_sCAL_s(png_ptr, (int)info_ptr->scal_unit,
+          info_ptr->scal_s_width, info_ptr->scal_s_height);
+#else
+      png_warning(png_ptr,
+          "png_write_sCAL not supported; sCAL chunk not written.");
+#endif
+#endif
+#endif
+#if defined(PNG_WRITE_pHYs_SUPPORTED)
+   if (info_ptr->valid & PNG_INFO_pHYs)
+      png_write_pHYs(png_ptr, info_ptr->x_pixels_per_unit,
+         info_ptr->y_pixels_per_unit, info_ptr->phys_unit_type);
+#endif
+#if defined(PNG_WRITE_tIME_SUPPORTED)
+   if (info_ptr->valid & PNG_INFO_tIME)
+   {
+      png_write_tIME(png_ptr, &(info_ptr->mod_time));
+      png_ptr->mode |= PNG_WROTE_tIME;
+   }
+#endif
+#if defined(PNG_WRITE_sPLT_SUPPORTED)
+   if (info_ptr->valid & PNG_INFO_sPLT)
+     for (i = 0; i < (int)info_ptr->splt_palettes_num; i++)
+       png_write_sPLT(png_ptr, info_ptr->splt_palettes + i);
+#endif
+#if defined(PNG_WRITE_TEXT_SUPPORTED)
+   /* Check to see if we need to write text chunks */
+   for (i = 0; i < info_ptr->num_text; i++)
+   {
+      png_debug2(2, "Writing header text chunk %d, type %d\n", i,
+         info_ptr->text[i].compression);
+      /* an internationalized chunk? */
+      if (info_ptr->text[i].compression > 0)
+      {
+#if defined(PNG_WRITE_iTXt_SUPPORTED)
+          /* write international chunk */
+          png_write_iTXt(png_ptr,
+                         info_ptr->text[i].compression,
+                         info_ptr->text[i].key,
+                         info_ptr->text[i].lang,
+                         info_ptr->text[i].lang_key,
+                         info_ptr->text[i].text);
+#else
+          png_warning(png_ptr, "Unable to write international text");
+#endif
+          /* Mark this chunk as written */
+          info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
+      }
+      /* If we want a compressed text chunk */
+      else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_zTXt)
+      {
+#if defined(PNG_WRITE_zTXt_SUPPORTED)
+         /* write compressed chunk */
+         png_write_zTXt(png_ptr, info_ptr->text[i].key,
+            info_ptr->text[i].text, 0,
+            info_ptr->text[i].compression);
+#else
+         png_warning(png_ptr, "Unable to write compressed text");
+#endif
+         /* Mark this chunk as written */
+         info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
+      }
+      else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
+      {
+#if defined(PNG_WRITE_tEXt_SUPPORTED)
+         /* write uncompressed chunk */
+         png_write_tEXt(png_ptr, info_ptr->text[i].key,
+                         info_ptr->text[i].text,
+                         0);
+#else
+         png_warning(png_ptr, "Unable to write uncompressed text");
+#endif
+         /* Mark this chunk as written */
+         info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
+      }
+   }
+#endif
+#if defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED)
+   if (info_ptr->unknown_chunks_num)
+   {
+       png_unknown_chunk *up;
+
+       png_debug(5, "writing extra chunks\n");
+
+       for (up = info_ptr->unknown_chunks;
+            up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;
+            up++)
+       {
+         int keep=png_handle_as_unknown(png_ptr, up->name);
+         if (keep != PNG_HANDLE_CHUNK_NEVER &&
+            up->location && (up->location & PNG_HAVE_PLTE) &&
+            !(up->location & PNG_HAVE_IDAT) &&
+            ((up->name[3] & 0x20) || keep == PNG_HANDLE_CHUNK_ALWAYS ||
+            (png_ptr->flags & PNG_FLAG_KEEP_UNSAFE_CHUNKS)))
+         {
+            png_write_chunk(png_ptr, up->name, up->data, up->size);
+         }
+       }
+   }
+#endif
+}
+
+/* Writes the end of the PNG file.  If you don't want to write comments or
+ * time information, you can pass NULL for info.  If you already wrote these
+ * in png_write_info(), do not write them again here.  If you have long
+ * comments, I suggest writing them here, and compressing them.
+ */
+void PNGAPI
+png_write_end(png_structp png_ptr, png_infop info_ptr)
+{
+   png_debug(1, "in png_write_end\n");
+   if (png_ptr == NULL)
+      return;
+   if (!(png_ptr->mode & PNG_HAVE_IDAT))
+      png_error(png_ptr, "No IDATs written into file");
+
+   /* see if user wants us to write information chunks */
+   if (info_ptr != NULL)
+   {
+#if defined(PNG_WRITE_TEXT_SUPPORTED)
+      int i; /* local index variable */
+#endif
+#if defined(PNG_WRITE_tIME_SUPPORTED)
+      /* check to see if user has supplied a time chunk */
+      if ((info_ptr->valid & PNG_INFO_tIME) &&
+         !(png_ptr->mode & PNG_WROTE_tIME))
+         png_write_tIME(png_ptr, &(info_ptr->mod_time));
+#endif
+#if defined(PNG_WRITE_TEXT_SUPPORTED)
+      /* loop through comment chunks */
+      for (i = 0; i < info_ptr->num_text; i++)
+      {
+         png_debug2(2, "Writing trailer text chunk %d, type %d\n", i,
+            info_ptr->text[i].compression);
+         /* an internationalized chunk? */
+         if (info_ptr->text[i].compression > 0)
+         {
+#if defined(PNG_WRITE_iTXt_SUPPORTED)
+             /* write international chunk */
+             png_write_iTXt(png_ptr,
+                         info_ptr->text[i].compression,
+                         info_ptr->text[i].key,
+                         info_ptr->text[i].lang,
+                         info_ptr->text[i].lang_key,
+                         info_ptr->text[i].text);
+#else
+             png_warning(png_ptr, "Unable to write international text");
+#endif
+             /* Mark this chunk as written */
+             info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
+         }
+         else if (info_ptr->text[i].compression >= PNG_TEXT_COMPRESSION_zTXt)
+         {
+#if defined(PNG_WRITE_zTXt_SUPPORTED)
+            /* write compressed chunk */
+            png_write_zTXt(png_ptr, info_ptr->text[i].key,
+               info_ptr->text[i].text, 0,
+               info_ptr->text[i].compression);
+#else
+            png_warning(png_ptr, "Unable to write compressed text");
+#endif
+            /* Mark this chunk as written */
+            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_zTXt_WR;
+         }
+         else if (info_ptr->text[i].compression == PNG_TEXT_COMPRESSION_NONE)
+         {
+#if defined(PNG_WRITE_tEXt_SUPPORTED)
+            /* write uncompressed chunk */
+            png_write_tEXt(png_ptr, info_ptr->text[i].key,
+               info_ptr->text[i].text, 0);
+#else
+            png_warning(png_ptr, "Unable to write uncompressed text");
+#endif
+
+            /* Mark this chunk as written */
+            info_ptr->text[i].compression = PNG_TEXT_COMPRESSION_NONE_WR;
+         }
+      }
+#endif
+#if defined(PNG_WRITE_UNKNOWN_CHUNKS_SUPPORTED)
+   if (info_ptr->unknown_chunks_num)
+   {
+       png_unknown_chunk *up;
+
+       png_debug(5, "writing extra chunks\n");
+
+       for (up = info_ptr->unknown_chunks;
+            up < info_ptr->unknown_chunks + info_ptr->unknown_chunks_num;
+            up++)
+       {
+         int keep=png_handle_as_unknown(png_ptr, up->name);
+         if (keep != PNG_HANDLE_CHUNK_NEVER &&
+            up->location && (up->location & PNG_AFTER_IDAT) &&
+            ((up->name[3] & 0x20) || keep == PNG_HANDLE_CHUNK_ALWAYS ||
+            (png_ptr->flags & PNG_FLAG_KEEP_UNSAFE_CHUNKS)))
+         {
+            png_write_chunk(png_ptr, up->name, up->data, up->size);
+         }
+       }
+   }
+#endif
+   }
+
+   png_ptr->mode |= PNG_AFTER_IDAT;
+
+   /* write end of PNG file */
+   png_write_IEND(png_ptr);
+}
+
+#if defined(PNG_WRITE_tIME_SUPPORTED)
+#if !defined(_WIN32_WCE)
+/* "time.h" functions are not supported on WindowsCE */
+void PNGAPI
+png_convert_from_struct_tm(png_timep ptime, struct tm FAR * ttime)
+{
+   png_debug(1, "in png_convert_from_struct_tm\n");
+   ptime->year = (png_uint_16)(1900 + ttime->tm_year);
+   ptime->month = (png_byte)(ttime->tm_mon + 1);
+   ptime->day = (png_byte)ttime->tm_mday;
+   ptime->hour = (png_byte)ttime->tm_hour;
+   ptime->minute = (png_byte)ttime->tm_min;
+   ptime->second = (png_byte)ttime->tm_sec;
+}
+
+void PNGAPI
+png_convert_from_time_t(png_timep ptime, time_t ttime)
+{
+   struct tm *tbuf;
+
+   png_debug(1, "in png_convert_from_time_t\n");
+   tbuf = gmtime(&ttime);
+   png_convert_from_struct_tm(ptime, tbuf);
+}
+#endif
+#endif
+
+/* Initialize png_ptr structure, and allocate any memory needed */
+png_structp PNGAPI
+png_create_write_struct(png_const_charp user_png_ver, png_voidp error_ptr,
+   png_error_ptr error_fn, png_error_ptr warn_fn)
+{
+#ifdef PNG_USER_MEM_SUPPORTED
+   return (png_create_write_struct_2(user_png_ver, error_ptr, error_fn,
+      warn_fn, png_voidp_NULL, png_malloc_ptr_NULL, png_free_ptr_NULL));
+}
+
+/* Alternate initialize png_ptr structure, and allocate any memory needed */
+png_structp PNGAPI
+png_create_write_struct_2(png_const_charp user_png_ver, png_voidp error_ptr,
+   png_error_ptr error_fn, png_error_ptr warn_fn, png_voidp mem_ptr,
+   png_malloc_ptr malloc_fn, png_free_ptr free_fn)
+{
+#endif /* PNG_USER_MEM_SUPPORTED */
+   png_structp png_ptr;
+#ifdef PNG_SETJMP_SUPPORTED
+#ifdef USE_FAR_KEYWORD
+   jmp_buf jmpbuf;
+#endif
+#endif
+   int i;
+   png_debug(1, "in png_create_write_struct\n");
+#ifdef PNG_USER_MEM_SUPPORTED
+   png_ptr = (png_structp)png_create_struct_2(PNG_STRUCT_PNG,
+      (png_malloc_ptr)malloc_fn, (png_voidp)mem_ptr);
+#else
+   png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
+#endif /* PNG_USER_MEM_SUPPORTED */
+   if (png_ptr == NULL)
+      return (NULL);
+
+#if !defined(PNG_1_0_X)
+#ifdef PNG_ASSEMBLER_CODE_SUPPORTED
+#ifdef PNG_MMX_CODE_SUPPORTED
+   png_init_mmx_flags(png_ptr);   /* 1.2.0 addition */
+#endif
+#endif
+#endif /* PNG_1_0_X */
+
+   /* added at libpng-1.2.6 */
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+   png_ptr->user_width_max=PNG_USER_WIDTH_MAX;
+   png_ptr->user_height_max=PNG_USER_HEIGHT_MAX;
+#endif
+
+#ifdef PNG_SETJMP_SUPPORTED
+#ifdef USE_FAR_KEYWORD
+   if (setjmp(jmpbuf))
+#else
+   if (setjmp(png_ptr->jmpbuf))
+#endif
+   {
+      png_free(png_ptr, png_ptr->zbuf);
+      png_ptr->zbuf=NULL;
+      png_destroy_struct(png_ptr);
+      return (NULL);
+   }
+#ifdef USE_FAR_KEYWORD
+   png_memcpy(png_ptr->jmpbuf,jmpbuf,png_sizeof(jmp_buf));
+#endif
+#endif
+
+#ifdef PNG_USER_MEM_SUPPORTED
+   png_set_mem_fn(png_ptr, mem_ptr, malloc_fn, free_fn);
+#endif /* PNG_USER_MEM_SUPPORTED */
+   png_set_error_fn(png_ptr, error_ptr, error_fn, warn_fn);
+
+   i=0;
+   do
+   {
+     if(user_png_ver[i] != png_libpng_ver[i])
+        png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
+   } while (png_libpng_ver[i++]);
+
+   if (png_ptr->flags & PNG_FLAG_LIBRARY_MISMATCH)
+   {
+     /* Libpng 0.90 and later are binary incompatible with libpng 0.89, so
+      * we must recompile any applications that use any older library version.
+      * For versions after libpng 1.0, we will be compatible, so we need
+      * only check the first digit.
+      */
+     if (user_png_ver == NULL || user_png_ver[0] != png_libpng_ver[0] ||
+         (user_png_ver[0] == '1' && user_png_ver[2] != png_libpng_ver[2]) ||
+         (user_png_ver[0] == '0' && user_png_ver[2] < '9'))
+     {
+#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
+        char msg[80];
+        if (user_png_ver)
+        {
+          png_snprintf(msg, 80,
+             "Application was compiled with png.h from libpng-%.20s",
+             user_png_ver);
+          png_warning(png_ptr, msg);
+        }
+        png_snprintf(msg, 80,
+           "Application  is  running with png.c from libpng-%.20s",
+           png_libpng_ver);
+        png_warning(png_ptr, msg);
+#endif
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+        png_ptr->flags=0;
+#endif
+        png_error(png_ptr,
+           "Incompatible libpng version in application and library");
+     }
+   }
+
+   /* initialize zbuf - compression buffer */
+   png_ptr->zbuf_size = PNG_ZBUF_SIZE;
+   png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
+      (png_uint_32)png_ptr->zbuf_size);
+
+   png_set_write_fn(png_ptr, png_voidp_NULL, png_rw_ptr_NULL,
+      png_flush_ptr_NULL);
+
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+   png_set_filter_heuristics(png_ptr, PNG_FILTER_HEURISTIC_DEFAULT,
+      1, png_doublep_NULL, png_doublep_NULL);
+#endif
+
+#ifdef PNG_SETJMP_SUPPORTED
+/* Applications that neglect to set up their own setjmp() and then encounter
+   a png_error() will longjmp here.  Since the jmpbuf is then meaningless we
+   abort instead of returning. */
+#ifdef USE_FAR_KEYWORD
+   if (setjmp(jmpbuf))
+      PNG_ABORT();
+   png_memcpy(png_ptr->jmpbuf,jmpbuf,png_sizeof(jmp_buf));
+#else
+   if (setjmp(png_ptr->jmpbuf))
+      PNG_ABORT();
+#endif
+#endif
+   return (png_ptr);
+}
+
+/* Initialize png_ptr structure, and allocate any memory needed */
+#if defined(PNG_1_0_X) || defined(PNG_1_2_X)
+/* Deprecated. */
+#undef png_write_init
+void PNGAPI
+png_write_init(png_structp png_ptr)
+{
+   /* We only come here via pre-1.0.7-compiled applications */
+   png_write_init_2(png_ptr, "1.0.6 or earlier", 0, 0);
+}
+
+void PNGAPI
+png_write_init_2(png_structp png_ptr, png_const_charp user_png_ver,
+   png_size_t png_struct_size, png_size_t png_info_size)
+{
+   /* We only come here via pre-1.0.12-compiled applications */
+   if(png_ptr == NULL) return;
+#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
+   if(png_sizeof(png_struct) > png_struct_size ||
+      png_sizeof(png_info) > png_info_size)
+   {
+      char msg[80];
+      png_ptr->warning_fn=NULL;
+      if (user_png_ver)
+      {
+        png_snprintf(msg, 80,
+           "Application was compiled with png.h from libpng-%.20s",
+           user_png_ver);
+        png_warning(png_ptr, msg);
+      }
+      png_snprintf(msg, 80,
+         "Application  is  running with png.c from libpng-%.20s",
+         png_libpng_ver);
+      png_warning(png_ptr, msg);
+   }
+#endif
+   if(png_sizeof(png_struct) > png_struct_size)
+     {
+       png_ptr->error_fn=NULL;
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+       png_ptr->flags=0;
+#endif
+       png_error(png_ptr,
+       "The png struct allocated by the application for writing is too small.");
+     }
+   if(png_sizeof(png_info) > png_info_size)
+     {
+       png_ptr->error_fn=NULL;
+#ifdef PNG_ERROR_NUMBERS_SUPPORTED
+       png_ptr->flags=0;
+#endif
+       png_error(png_ptr,
+       "The info struct allocated by the application for writing is too small.");
+     }
+   png_write_init_3(&png_ptr, user_png_ver, png_struct_size);
+}
+#endif /* PNG_1_0_X || PNG_1_2_X */
+
+
+void PNGAPI
+png_write_init_3(png_structpp ptr_ptr, png_const_charp user_png_ver,
+   png_size_t png_struct_size)
+{
+   png_structp png_ptr=*ptr_ptr;
+#ifdef PNG_SETJMP_SUPPORTED
+   jmp_buf tmp_jmp; /* to save current jump buffer */
+#endif
+
+   int i = 0;
+
+   if (png_ptr == NULL)
+      return;
+
+   do
+   {
+     if (user_png_ver[i] != png_libpng_ver[i])
+     {
+#ifdef PNG_LEGACY_SUPPORTED
+       png_ptr->flags |= PNG_FLAG_LIBRARY_MISMATCH;
+#else
+       png_ptr->warning_fn=NULL;
+       png_warning(png_ptr,
+     "Application uses deprecated png_write_init() and should be recompiled.");
+       break;
+#endif
+     }
+   } while (png_libpng_ver[i++]);
+
+   png_debug(1, "in png_write_init_3\n");
+
+#ifdef PNG_SETJMP_SUPPORTED
+   /* save jump buffer and error functions */
+   png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof (jmp_buf));
+#endif
+
+   if (png_sizeof(png_struct) > png_struct_size)
+     {
+       png_destroy_struct(png_ptr);
+       png_ptr = (png_structp)png_create_struct(PNG_STRUCT_PNG);
+       *ptr_ptr = png_ptr;
+     }
+
+   /* reset all variables to 0 */
+   png_memset(png_ptr, 0, png_sizeof (png_struct));
+
+   /* added at libpng-1.2.6 */
+#ifdef PNG_SET_USER_LIMITS_SUPPORTED
+   png_ptr->user_width_max=PNG_USER_WIDTH_MAX;
+   png_ptr->user_height_max=PNG_USER_HEIGHT_MAX;
+#endif
+
+#if !defined(PNG_1_0_X)
+#ifdef PNG_ASSEMBLER_CODE_SUPPORTED
+#ifdef PNG_MMX_CODE_SUPPORTED
+   png_init_mmx_flags(png_ptr);   /* 1.2.0 addition */
+#endif
+#endif
+#endif /* PNG_1_0_X */
+
+#ifdef PNG_SETJMP_SUPPORTED
+   /* restore jump buffer */
+   png_memcpy(png_ptr->jmpbuf, tmp_jmp, png_sizeof (jmp_buf));
+#endif
+
+   png_set_write_fn(png_ptr, png_voidp_NULL, png_rw_ptr_NULL,
+      png_flush_ptr_NULL);
+
+   /* initialize zbuf - compression buffer */
+   png_ptr->zbuf_size = PNG_ZBUF_SIZE;
+   png_ptr->zbuf = (png_bytep)png_malloc(png_ptr,
+      (png_uint_32)png_ptr->zbuf_size);
+
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+   png_set_filter_heuristics(png_ptr, PNG_FILTER_HEURISTIC_DEFAULT,
+      1, png_doublep_NULL, png_doublep_NULL);
+#endif
+}
+
+/* Write a few rows of image data.  If the image is interlaced,
+ * either you will have to write the 7 sub images, or, if you
+ * have called png_set_interlace_handling(), you will have to
+ * "write" the image seven times.
+ */
+void PNGAPI
+png_write_rows(png_structp png_ptr, png_bytepp row,
+   png_uint_32 num_rows)
+{
+   png_uint_32 i; /* row counter */
+   png_bytepp rp; /* row pointer */
+
+   png_debug(1, "in png_write_rows\n");
+
+   if (png_ptr == NULL)
+      return;
+
+   /* loop through the rows */
+   for (i = 0, rp = row; i < num_rows; i++, rp++)
+   {
+      png_write_row(png_ptr, *rp);
+   }
+}
+
+/* Write the image.  You only need to call this function once, even
+ * if you are writing an interlaced image.
+ */
+void PNGAPI
+png_write_image(png_structp png_ptr, png_bytepp image)
+{
+   png_uint_32 i; /* row index */
+   int pass, num_pass; /* pass variables */
+   png_bytepp rp; /* points to current row */
+
+   if (png_ptr == NULL)
+      return;
+
+   png_debug(1, "in png_write_image\n");
+#if defined(PNG_WRITE_INTERLACING_SUPPORTED)
+   /* intialize interlace handling.  If image is not interlaced,
+      this will set pass to 1 */
+   num_pass = png_set_interlace_handling(png_ptr);
+#else
+   num_pass = 1;
+#endif
+   /* loop through passes */
+   for (pass = 0; pass < num_pass; pass++)
+   {
+      /* loop through image */
+      for (i = 0, rp = image; i < png_ptr->height; i++, rp++)
+      {
+         png_write_row(png_ptr, *rp);
+      }
+   }
+}
+
+/* called by user to write a row of image data */
+void PNGAPI
+png_write_row(png_structp png_ptr, png_bytep row)
+{
+   if (png_ptr == NULL)
+      return;
+   png_debug2(1, "in png_write_row (row %ld, pass %d)\n",
+      png_ptr->row_number, png_ptr->pass);
+
+   /* initialize transformations and other stuff if first time */
+   if (png_ptr->row_number == 0 && png_ptr->pass == 0)
+   {
+   /* make sure we wrote the header info */
+   if (!(png_ptr->mode & PNG_WROTE_INFO_BEFORE_PLTE))
+      png_error(png_ptr,
+         "png_write_info was never called before png_write_row.");
+
+   /* check for transforms that have been set but were defined out */
+#if !defined(PNG_WRITE_INVERT_SUPPORTED) && defined(PNG_READ_INVERT_SUPPORTED)
+   if (png_ptr->transformations & PNG_INVERT_MONO)
+      png_warning(png_ptr, "PNG_WRITE_INVERT_SUPPORTED is not defined.");
+#endif
+#if !defined(PNG_WRITE_FILLER_SUPPORTED) && defined(PNG_READ_FILLER_SUPPORTED)
+   if (png_ptr->transformations & PNG_FILLER)
+      png_warning(png_ptr, "PNG_WRITE_FILLER_SUPPORTED is not defined.");
+#endif
+#if !defined(PNG_WRITE_PACKSWAP_SUPPORTED) && defined(PNG_READ_PACKSWAP_SUPPORTED)
+   if (png_ptr->transformations & PNG_PACKSWAP)
+      png_warning(png_ptr, "PNG_WRITE_PACKSWAP_SUPPORTED is not defined.");
+#endif
+#if !defined(PNG_WRITE_PACK_SUPPORTED) && defined(PNG_READ_PACK_SUPPORTED)
+   if (png_ptr->transformations & PNG_PACK)
+      png_warning(png_ptr, "PNG_WRITE_PACK_SUPPORTED is not defined.");
+#endif
+#if !defined(PNG_WRITE_SHIFT_SUPPORTED) && defined(PNG_READ_SHIFT_SUPPORTED)
+   if (png_ptr->transformations & PNG_SHIFT)
+      png_warning(png_ptr, "PNG_WRITE_SHIFT_SUPPORTED is not defined.");
+#endif
+#if !defined(PNG_WRITE_BGR_SUPPORTED) && defined(PNG_READ_BGR_SUPPORTED)
+   if (png_ptr->transformations & PNG_BGR)
+      png_warning(png_ptr, "PNG_WRITE_BGR_SUPPORTED is not defined.");
+#endif
+#if !defined(PNG_WRITE_SWAP_SUPPORTED) && defined(PNG_READ_SWAP_SUPPORTED)
+   if (png_ptr->transformations & PNG_SWAP_BYTES)
+      png_warning(png_ptr, "PNG_WRITE_SWAP_SUPPORTED is not defined.");
+#endif
+
+      png_write_start_row(png_ptr);
+   }
+
+#if defined(PNG_WRITE_INTERLACING_SUPPORTED)
+   /* if interlaced and not interested in row, return */
+   if (png_ptr->interlaced && (png_ptr->transformations & PNG_INTERLACE))
+   {
+      switch (png_ptr->pass)
+      {
+         case 0:
+            if (png_ptr->row_number & 0x07)
+            {
+               png_write_finish_row(png_ptr);
+               return;
+            }
+            break;
+         case 1:
+            if ((png_ptr->row_number & 0x07) || png_ptr->width < 5)
+            {
+               png_write_finish_row(png_ptr);
+               return;
+            }
+            break;
+         case 2:
+            if ((png_ptr->row_number & 0x07) != 4)
+            {
+               png_write_finish_row(png_ptr);
+               return;
+            }
+            break;
+         case 3:
+            if ((png_ptr->row_number & 0x03) || png_ptr->width < 3)
+            {
+               png_write_finish_row(png_ptr);
+               return;
+            }
+            break;
+         case 4:
+            if ((png_ptr->row_number & 0x03) != 2)
+            {
+               png_write_finish_row(png_ptr);
+               return;
+            }
+            break;
+         case 5:
+            if ((png_ptr->row_number & 0x01) || png_ptr->width < 2)
+            {
+               png_write_finish_row(png_ptr);
+               return;
+            }
+            break;
+         case 6:
+            if (!(png_ptr->row_number & 0x01))
+            {
+               png_write_finish_row(png_ptr);
+               return;
+            }
+            break;
+      }
+   }
+#endif
+
+   /* set up row info for transformations */
+   png_ptr->row_info.color_type = png_ptr->color_type;
+   png_ptr->row_info.width = png_ptr->usr_width;
+   png_ptr->row_info.channels = png_ptr->usr_channels;
+   png_ptr->row_info.bit_depth = png_ptr->usr_bit_depth;
+   png_ptr->row_info.pixel_depth = (png_byte)(png_ptr->row_info.bit_depth *
+      png_ptr->row_info.channels);
+
+   png_ptr->row_info.rowbytes = PNG_ROWBYTES(png_ptr->row_info.pixel_depth,
+      png_ptr->row_info.width);
+
+   png_debug1(3, "row_info->color_type = %d\n", png_ptr->row_info.color_type);
+   png_debug1(3, "row_info->width = %lu\n", png_ptr->row_info.width);
+   png_debug1(3, "row_info->channels = %d\n", png_ptr->row_info.channels);
+   png_debug1(3, "row_info->bit_depth = %d\n", png_ptr->row_info.bit_depth);
+   png_debug1(3, "row_info->pixel_depth = %d\n", png_ptr->row_info.pixel_depth);
+   png_debug1(3, "row_info->rowbytes = %lu\n", png_ptr->row_info.rowbytes);
+
+   /* Copy user's row into buffer, leaving room for filter byte. */
+   png_memcpy_check(png_ptr, png_ptr->row_buf + 1, row,
+      png_ptr->row_info.rowbytes);
+
+#if defined(PNG_WRITE_INTERLACING_SUPPORTED)
+   /* handle interlacing */
+   if (png_ptr->interlaced && png_ptr->pass < 6 &&
+      (png_ptr->transformations & PNG_INTERLACE))
+   {
+      png_do_write_interlace(&(png_ptr->row_info),
+         png_ptr->row_buf + 1, png_ptr->pass);
+      /* this should always get caught above, but still ... */
+      if (!(png_ptr->row_info.width))
+      {
+         png_write_finish_row(png_ptr);
+         return;
+      }
+   }
+#endif
+
+   /* handle other transformations */
+   if (png_ptr->transformations)
+      png_do_write_transformations(png_ptr);
+
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
+   /* Write filter_method 64 (intrapixel differencing) only if
+    * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
+    * 2. Libpng did not write a PNG signature (this filter_method is only
+    *    used in PNG datastreams that are embedded in MNG datastreams) and
+    * 3. The application called png_permit_mng_features with a mask that
+    *    included PNG_FLAG_MNG_FILTER_64 and
+    * 4. The filter_method is 64 and
+    * 5. The color_type is RGB or RGBA
+    */
+   if((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
+      (png_ptr->filter_type == PNG_INTRAPIXEL_DIFFERENCING))
+   {
+      /* Intrapixel differencing */
+      png_do_write_intrapixel(&(png_ptr->row_info), png_ptr->row_buf + 1);
+   }
+#endif
+
+   /* Find a filter if necessary, filter the row and write it out. */
+   png_write_find_filter(png_ptr, &(png_ptr->row_info));
+
+   if (png_ptr->write_row_fn != NULL)
+      (*(png_ptr->write_row_fn))(png_ptr, png_ptr->row_number, png_ptr->pass);
+}
+
+#if defined(PNG_WRITE_FLUSH_SUPPORTED)
+/* Set the automatic flush interval or 0 to turn flushing off */
+void PNGAPI
+png_set_flush(png_structp png_ptr, int nrows)
+{
+   png_debug(1, "in png_set_flush\n");
+   if (png_ptr == NULL)
+      return;
+   png_ptr->flush_dist = (nrows < 0 ? 0 : nrows);
+}
+
+/* flush the current output buffers now */
+void PNGAPI
+png_write_flush(png_structp png_ptr)
+{
+   int wrote_IDAT;
+
+   png_debug(1, "in png_write_flush\n");
+   if (png_ptr == NULL)
+      return;
+   /* We have already written out all of the data */
+   if (png_ptr->row_number >= png_ptr->num_rows)
+     return;
+
+   do
+   {
+      int ret;
+
+      /* compress the data */
+      ret = deflate(&png_ptr->zstream, Z_SYNC_FLUSH);
+      wrote_IDAT = 0;
+
+      /* check for compression errors */
+      if (ret != Z_OK)
+      {
+         if (png_ptr->zstream.msg != NULL)
+            png_error(png_ptr, png_ptr->zstream.msg);
+         else
+            png_error(png_ptr, "zlib error");
+      }
+
+      if (!(png_ptr->zstream.avail_out))
+      {
+         /* write the IDAT and reset the zlib output buffer */
+         png_write_IDAT(png_ptr, png_ptr->zbuf,
+                        png_ptr->zbuf_size);
+         png_ptr->zstream.next_out = png_ptr->zbuf;
+         png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+         wrote_IDAT = 1;
+      }
+   } while(wrote_IDAT == 1);
+
+   /* If there is any data left to be output, write it into a new IDAT */
+   if (png_ptr->zbuf_size != png_ptr->zstream.avail_out)
+   {
+      /* write the IDAT and reset the zlib output buffer */
+      png_write_IDAT(png_ptr, png_ptr->zbuf,
+                     png_ptr->zbuf_size - png_ptr->zstream.avail_out);
+      png_ptr->zstream.next_out = png_ptr->zbuf;
+      png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+   }
+   png_ptr->flush_rows = 0;
+   png_flush(png_ptr);
+}
+#endif /* PNG_WRITE_FLUSH_SUPPORTED */
+
+/* free all memory used by the write */
+void PNGAPI
+png_destroy_write_struct(png_structpp png_ptr_ptr, png_infopp info_ptr_ptr)
+{
+   png_structp png_ptr = NULL;
+   png_infop info_ptr = NULL;
+#ifdef PNG_USER_MEM_SUPPORTED
+   png_free_ptr free_fn = NULL;
+   png_voidp mem_ptr = NULL;
+#endif
+
+   png_debug(1, "in png_destroy_write_struct\n");
+   if (png_ptr_ptr != NULL)
+   {
+      png_ptr = *png_ptr_ptr;
+#ifdef PNG_USER_MEM_SUPPORTED
+      free_fn = png_ptr->free_fn;
+      mem_ptr = png_ptr->mem_ptr;
+#endif
+   }
+
+   if (info_ptr_ptr != NULL)
+      info_ptr = *info_ptr_ptr;
+
+   if (info_ptr != NULL)
+   {
+      png_free_data(png_ptr, info_ptr, PNG_FREE_ALL, -1);
+
+#if defined(PNG_UNKNOWN_CHUNKS_SUPPORTED)
+      if (png_ptr->num_chunk_list)
+      {
+         png_free(png_ptr, png_ptr->chunk_list);
+         png_ptr->chunk_list=NULL;
+         png_ptr->num_chunk_list=0;
+      }
+#endif
+
+#ifdef PNG_USER_MEM_SUPPORTED
+      png_destroy_struct_2((png_voidp)info_ptr, (png_free_ptr)free_fn,
+         (png_voidp)mem_ptr);
+#else
+      png_destroy_struct((png_voidp)info_ptr);
+#endif
+      *info_ptr_ptr = NULL;
+   }
+
+   if (png_ptr != NULL)
+   {
+      png_write_destroy(png_ptr);
+#ifdef PNG_USER_MEM_SUPPORTED
+      png_destroy_struct_2((png_voidp)png_ptr, (png_free_ptr)free_fn,
+         (png_voidp)mem_ptr);
+#else
+      png_destroy_struct((png_voidp)png_ptr);
+#endif
+      *png_ptr_ptr = NULL;
+   }
+}
+
+
+/* Free any memory used in png_ptr struct (old method) */
+void /* PRIVATE */
+png_write_destroy(png_structp png_ptr)
+{
+#ifdef PNG_SETJMP_SUPPORTED
+   jmp_buf tmp_jmp; /* save jump buffer */
+#endif
+   png_error_ptr error_fn;
+   png_error_ptr warning_fn;
+   png_voidp error_ptr;
+#ifdef PNG_USER_MEM_SUPPORTED
+   png_free_ptr free_fn;
+#endif
+
+   png_debug(1, "in png_write_destroy\n");
+   /* free any memory zlib uses */
+   deflateEnd(&png_ptr->zstream);
+
+   /* free our memory.  png_free checks NULL for us. */
+   png_free(png_ptr, png_ptr->zbuf);
+   png_free(png_ptr, png_ptr->row_buf);
+   png_free(png_ptr, png_ptr->prev_row);
+   png_free(png_ptr, png_ptr->sub_row);
+   png_free(png_ptr, png_ptr->up_row);
+   png_free(png_ptr, png_ptr->avg_row);
+   png_free(png_ptr, png_ptr->paeth_row);
+
+#if defined(PNG_TIME_RFC1123_SUPPORTED)
+   png_free(png_ptr, png_ptr->time_buffer);
+#endif
+
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+   png_free(png_ptr, png_ptr->prev_filters);
+   png_free(png_ptr, png_ptr->filter_weights);
+   png_free(png_ptr, png_ptr->inv_filter_weights);
+   png_free(png_ptr, png_ptr->filter_costs);
+   png_free(png_ptr, png_ptr->inv_filter_costs);
+#endif
+
+#ifdef PNG_SETJMP_SUPPORTED
+   /* reset structure */
+   png_memcpy(tmp_jmp, png_ptr->jmpbuf, png_sizeof (jmp_buf));
+#endif
+
+   error_fn = png_ptr->error_fn;
+   warning_fn = png_ptr->warning_fn;
+   error_ptr = png_ptr->error_ptr;
+#ifdef PNG_USER_MEM_SUPPORTED
+   free_fn = png_ptr->free_fn;
+#endif
+
+   png_memset(png_ptr, 0, png_sizeof (png_struct));
+
+   png_ptr->error_fn = error_fn;
+   png_ptr->warning_fn = warning_fn;
+   png_ptr->error_ptr = error_ptr;
+#ifdef PNG_USER_MEM_SUPPORTED
+   png_ptr->free_fn = free_fn;
+#endif
+
+#ifdef PNG_SETJMP_SUPPORTED
+   png_memcpy(png_ptr->jmpbuf, tmp_jmp, png_sizeof (jmp_buf));
+#endif
+}
+
+/* Allow the application to select one or more row filters to use. */
+void PNGAPI
+png_set_filter(png_structp png_ptr, int method, int filters)
+{
+   png_debug(1, "in png_set_filter\n");
+   if (png_ptr == NULL)
+      return;
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
+   if((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
+      (method == PNG_INTRAPIXEL_DIFFERENCING))
+         method = PNG_FILTER_TYPE_BASE;
+#endif
+   if (method == PNG_FILTER_TYPE_BASE)
+   {
+      switch (filters & (PNG_ALL_FILTERS | 0x07))
+      {
+#ifndef PNG_NO_WRITE_FILTER
+         case 5:
+         case 6:
+         case 7: png_warning(png_ptr, "Unknown row filter for method 0");
+#endif /* PNG_NO_WRITE_FILTER */
+         case PNG_FILTER_VALUE_NONE:
+              png_ptr->do_filter=PNG_FILTER_NONE; break;
+#ifndef PNG_NO_WRITE_FILTER
+         case PNG_FILTER_VALUE_SUB:
+              png_ptr->do_filter=PNG_FILTER_SUB; break;
+         case PNG_FILTER_VALUE_UP:
+              png_ptr->do_filter=PNG_FILTER_UP; break;
+         case PNG_FILTER_VALUE_AVG:
+              png_ptr->do_filter=PNG_FILTER_AVG; break;
+         case PNG_FILTER_VALUE_PAETH:
+              png_ptr->do_filter=PNG_FILTER_PAETH; break;
+         default: png_ptr->do_filter = (png_byte)filters; break;
+#else
+         default: png_warning(png_ptr, "Unknown row filter for method 0");
+#endif /* PNG_NO_WRITE_FILTER */
+      }
+
+      /* If we have allocated the row_buf, this means we have already started
+       * with the image and we should have allocated all of the filter buffers
+       * that have been selected.  If prev_row isn't already allocated, then
+       * it is too late to start using the filters that need it, since we
+       * will be missing the data in the previous row.  If an application
+       * wants to start and stop using particular filters during compression,
+       * it should start out with all of the filters, and then add and
+       * remove them after the start of compression.
+       */
+      if (png_ptr->row_buf != NULL)
+      {
+#ifndef PNG_NO_WRITE_FILTER
+         if ((png_ptr->do_filter & PNG_FILTER_SUB) && png_ptr->sub_row == NULL)
+         {
+            png_ptr->sub_row = (png_bytep)png_malloc(png_ptr,
+              (png_ptr->rowbytes + 1));
+            png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
+         }
+
+         if ((png_ptr->do_filter & PNG_FILTER_UP) && png_ptr->up_row == NULL)
+         {
+            if (png_ptr->prev_row == NULL)
+            {
+               png_warning(png_ptr, "Can't add Up filter after starting");
+               png_ptr->do_filter &= ~PNG_FILTER_UP;
+            }
+            else
+            {
+               png_ptr->up_row = (png_bytep)png_malloc(png_ptr,
+                  (png_ptr->rowbytes + 1));
+               png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
+            }
+         }
+
+         if ((png_ptr->do_filter & PNG_FILTER_AVG) && png_ptr->avg_row == NULL)
+         {
+            if (png_ptr->prev_row == NULL)
+            {
+               png_warning(png_ptr, "Can't add Average filter after starting");
+               png_ptr->do_filter &= ~PNG_FILTER_AVG;
+            }
+            else
+            {
+               png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,
+                  (png_ptr->rowbytes + 1));
+               png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
+            }
+         }
+
+         if ((png_ptr->do_filter & PNG_FILTER_PAETH) &&
+             png_ptr->paeth_row == NULL)
+         {
+            if (png_ptr->prev_row == NULL)
+            {
+               png_warning(png_ptr, "Can't add Paeth filter after starting");
+               png_ptr->do_filter &= (png_byte)(~PNG_FILTER_PAETH);
+            }
+            else
+            {
+               png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,
+                  (png_ptr->rowbytes + 1));
+               png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
+            }
+         }
+
+         if (png_ptr->do_filter == PNG_NO_FILTERS)
+#endif /* PNG_NO_WRITE_FILTER */
+            png_ptr->do_filter = PNG_FILTER_NONE;
+      }
+   }
+   else
+      png_error(png_ptr, "Unknown custom filter method");
+}
+
+/* This allows us to influence the way in which libpng chooses the "best"
+ * filter for the current scanline.  While the "minimum-sum-of-absolute-
+ * differences metric is relatively fast and effective, there is some
+ * question as to whether it can be improved upon by trying to keep the
+ * filtered data going to zlib more consistent, hopefully resulting in
+ * better compression.
+ */
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)      /* GRR 970116 */
+void PNGAPI
+png_set_filter_heuristics(png_structp png_ptr, int heuristic_method,
+   int num_weights, png_doublep filter_weights,
+   png_doublep filter_costs)
+{
+   int i;
+
+   png_debug(1, "in png_set_filter_heuristics\n");
+   if (png_ptr == NULL)
+      return;
+   if (heuristic_method >= PNG_FILTER_HEURISTIC_LAST)
+   {
+      png_warning(png_ptr, "Unknown filter heuristic method");
+      return;
+   }
+
+   if (heuristic_method == PNG_FILTER_HEURISTIC_DEFAULT)
+   {
+      heuristic_method = PNG_FILTER_HEURISTIC_UNWEIGHTED;
+   }
+
+   if (num_weights < 0 || filter_weights == NULL ||
+      heuristic_method == PNG_FILTER_HEURISTIC_UNWEIGHTED)
+   {
+      num_weights = 0;
+   }
+
+   png_ptr->num_prev_filters = (png_byte)num_weights;
+   png_ptr->heuristic_method = (png_byte)heuristic_method;
+
+   if (num_weights > 0)
+   {
+      if (png_ptr->prev_filters == NULL)
+      {
+         png_ptr->prev_filters = (png_bytep)png_malloc(png_ptr,
+            (png_uint_32)(png_sizeof(png_byte) * num_weights));
+
+         /* To make sure that the weighting starts out fairly */
+         for (i = 0; i < num_weights; i++)
+         {
+            png_ptr->prev_filters[i] = 255;
+         }
+      }
+
+      if (png_ptr->filter_weights == NULL)
+      {
+         png_ptr->filter_weights = (png_uint_16p)png_malloc(png_ptr,
+            (png_uint_32)(png_sizeof(png_uint_16) * num_weights));
+
+         png_ptr->inv_filter_weights = (png_uint_16p)png_malloc(png_ptr,
+            (png_uint_32)(png_sizeof(png_uint_16) * num_weights));
+         for (i = 0; i < num_weights; i++)
+         {
+            png_ptr->inv_filter_weights[i] =
+            png_ptr->filter_weights[i] = PNG_WEIGHT_FACTOR;
+         }
+      }
+
+      for (i = 0; i < num_weights; i++)
+      {
+         if (filter_weights[i] < 0.0)
+         {
+            png_ptr->inv_filter_weights[i] =
+            png_ptr->filter_weights[i] = PNG_WEIGHT_FACTOR;
+         }
+         else
+         {
+            png_ptr->inv_filter_weights[i] =
+               (png_uint_16)((double)PNG_WEIGHT_FACTOR*filter_weights[i]+0.5);
+            png_ptr->filter_weights[i] =
+               (png_uint_16)((double)PNG_WEIGHT_FACTOR/filter_weights[i]+0.5);
+         }
+      }
+   }
+
+   /* If, in the future, there are other filter methods, this would
+    * need to be based on png_ptr->filter.
+    */
+   if (png_ptr->filter_costs == NULL)
+   {
+      png_ptr->filter_costs = (png_uint_16p)png_malloc(png_ptr,
+         (png_uint_32)(png_sizeof(png_uint_16) * PNG_FILTER_VALUE_LAST));
+
+      png_ptr->inv_filter_costs = (png_uint_16p)png_malloc(png_ptr,
+         (png_uint_32)(png_sizeof(png_uint_16) * PNG_FILTER_VALUE_LAST));
+
+      for (i = 0; i < PNG_FILTER_VALUE_LAST; i++)
+      {
+         png_ptr->inv_filter_costs[i] =
+         png_ptr->filter_costs[i] = PNG_COST_FACTOR;
+      }
+   }
+
+   /* Here is where we set the relative costs of the different filters.  We
+    * should take the desired compression level into account when setting
+    * the costs, so that Paeth, for instance, has a high relative cost at low
+    * compression levels, while it has a lower relative cost at higher
+    * compression settings.  The filter types are in order of increasing
+    * relative cost, so it would be possible to do this with an algorithm.
+    */
+   for (i = 0; i < PNG_FILTER_VALUE_LAST; i++)
+   {
+      if (filter_costs == NULL || filter_costs[i] < 0.0)
+      {
+         png_ptr->inv_filter_costs[i] =
+         png_ptr->filter_costs[i] = PNG_COST_FACTOR;
+      }
+      else if (filter_costs[i] >= 1.0)
+      {
+         png_ptr->inv_filter_costs[i] =
+            (png_uint_16)((double)PNG_COST_FACTOR / filter_costs[i] + 0.5);
+         png_ptr->filter_costs[i] =
+            (png_uint_16)((double)PNG_COST_FACTOR * filter_costs[i] + 0.5);
+      }
+   }
+}
+#endif /* PNG_WRITE_WEIGHTED_FILTER_SUPPORTED */
+
+void PNGAPI
+png_set_compression_level(png_structp png_ptr, int level)
+{
+   png_debug(1, "in png_set_compression_level\n");
+   if (png_ptr == NULL)
+      return;
+   png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_LEVEL;
+   png_ptr->zlib_level = level;
+}
+
+void PNGAPI
+png_set_compression_mem_level(png_structp png_ptr, int mem_level)
+{
+   png_debug(1, "in png_set_compression_mem_level\n");
+   if (png_ptr == NULL)
+      return;
+   png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL;
+   png_ptr->zlib_mem_level = mem_level;
+}
+
+void PNGAPI
+png_set_compression_strategy(png_structp png_ptr, int strategy)
+{
+   png_debug(1, "in png_set_compression_strategy\n");
+   if (png_ptr == NULL)
+      return;
+   png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_STRATEGY;
+   png_ptr->zlib_strategy = strategy;
+}
+
+void PNGAPI
+png_set_compression_window_bits(png_structp png_ptr, int window_bits)
+{
+   if (png_ptr == NULL)
+      return;
+   if (window_bits > 15)
+      png_warning(png_ptr, "Only compression windows <= 32k supported by PNG");
+   else if (window_bits < 8)
+      png_warning(png_ptr, "Only compression windows >= 256 supported by PNG");
+#ifndef WBITS_8_OK
+   /* avoid libpng bug with 256-byte windows */
+   if (window_bits == 8)
+     {
+       png_warning(png_ptr, "Compression window is being reset to 512");
+       window_bits=9;
+     }
+#endif
+   png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS;
+   png_ptr->zlib_window_bits = window_bits;
+}
+
+void PNGAPI
+png_set_compression_method(png_structp png_ptr, int method)
+{
+   png_debug(1, "in png_set_compression_method\n");
+   if (png_ptr == NULL)
+      return;
+   if (method != 8)
+      png_warning(png_ptr, "Only compression method 8 is supported by PNG");
+   png_ptr->flags |= PNG_FLAG_ZLIB_CUSTOM_METHOD;
+   png_ptr->zlib_method = method;
+}
+
+void PNGAPI
+png_set_write_status_fn(png_structp png_ptr, png_write_status_ptr write_row_fn)
+{
+   if (png_ptr == NULL)
+      return;
+   png_ptr->write_row_fn = write_row_fn;
+}
+
+#if defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
+void PNGAPI
+png_set_write_user_transform_fn(png_structp png_ptr, png_user_transform_ptr
+   write_user_transform_fn)
+{
+   png_debug(1, "in png_set_write_user_transform_fn\n");
+   if (png_ptr == NULL)
+      return;
+   png_ptr->transformations |= PNG_USER_TRANSFORM;
+   png_ptr->write_user_transform_fn = write_user_transform_fn;
+}
+#endif
+
+
+#if defined(PNG_INFO_IMAGE_SUPPORTED)
+void PNGAPI
+png_write_png(png_structp png_ptr, png_infop info_ptr,
+              int transforms, voidp params)
+{
+   if (png_ptr == NULL || info_ptr == NULL)
+      return;
+#if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
+   /* invert the alpha channel from opacity to transparency */
+   if (transforms & PNG_TRANSFORM_INVERT_ALPHA)
+       png_set_invert_alpha(png_ptr);
+#endif
+
+   /* Write the file header information. */
+   png_write_info(png_ptr, info_ptr);
+
+   /* ------ these transformations don't touch the info structure ------- */
+
+#if defined(PNG_WRITE_INVERT_SUPPORTED)
+   /* invert monochrome pixels */
+   if (transforms & PNG_TRANSFORM_INVERT_MONO)
+       png_set_invert_mono(png_ptr);
+#endif
+
+#if defined(PNG_WRITE_SHIFT_SUPPORTED)
+   /* Shift the pixels up to a legal bit depth and fill in
+    * as appropriate to correctly scale the image.
+    */
+   if ((transforms & PNG_TRANSFORM_SHIFT)
+               && (info_ptr->valid & PNG_INFO_sBIT))
+       png_set_shift(png_ptr, &info_ptr->sig_bit);
+#endif
+
+#if defined(PNG_WRITE_PACK_SUPPORTED)
+   /* pack pixels into bytes */
+   if (transforms & PNG_TRANSFORM_PACKING)
+       png_set_packing(png_ptr);
+#endif
+
+#if defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
+   /* swap location of alpha bytes from ARGB to RGBA */
+   if (transforms & PNG_TRANSFORM_SWAP_ALPHA)
+       png_set_swap_alpha(png_ptr);
+#endif
+
+#if defined(PNG_WRITE_FILLER_SUPPORTED)
+   /* Get rid of filler (OR ALPHA) bytes, pack XRGB/RGBX/ARGB/RGBA into
+    * RGB (4 channels -> 3 channels). The second parameter is not used.
+    */
+   if (transforms & PNG_TRANSFORM_STRIP_FILLER)
+       png_set_filler(png_ptr, 0, PNG_FILLER_BEFORE);
+#endif
+
+#if defined(PNG_WRITE_BGR_SUPPORTED)
+   /* flip BGR pixels to RGB */
+   if (transforms & PNG_TRANSFORM_BGR)
+       png_set_bgr(png_ptr);
+#endif
+
+#if defined(PNG_WRITE_SWAP_SUPPORTED)
+   /* swap bytes of 16-bit files to most significant byte first */
+   if (transforms & PNG_TRANSFORM_SWAP_ENDIAN)
+       png_set_swap(png_ptr);
+#endif
+
+#if defined(PNG_WRITE_PACKSWAP_SUPPORTED)
+   /* swap bits of 1, 2, 4 bit packed pixel formats */
+   if (transforms & PNG_TRANSFORM_PACKSWAP)
+       png_set_packswap(png_ptr);
+#endif
+
+   /* ----------------------- end of transformations ------------------- */
+
+   /* write the bits */
+   if (info_ptr->valid & PNG_INFO_IDAT)
+       png_write_image(png_ptr, info_ptr->row_pointers);
+
+   /* It is REQUIRED to call this to finish writing the rest of the file */
+   png_write_end(png_ptr, info_ptr);
+
+   transforms = transforms; /* quiet compiler warnings */
+   params = params;
+}
+#endif
+#endif /* PNG_WRITE_SUPPORTED */
diff --git a/distrib/libpng-1.2.19/pngwtran.c b/distrib/libpng-1.2.19/pngwtran.c
new file mode 100644
index 0000000..0372fe6
--- /dev/null
+++ b/distrib/libpng-1.2.19/pngwtran.c
@@ -0,0 +1,572 @@
+
+/* pngwtran.c - transforms the data in a row for PNG writers
+ *
+ * Last changed in libpng 1.2.9 April 14, 2006
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1998-2006 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ */
+
+#define PNG_INTERNAL
+#include "png.h"
+#ifdef PNG_WRITE_SUPPORTED
+
+/* Transform the data according to the user's wishes.  The order of
+ * transformations is significant.
+ */
+void /* PRIVATE */
+png_do_write_transformations(png_structp png_ptr)
+{
+   png_debug(1, "in png_do_write_transformations\n");
+
+   if (png_ptr == NULL)
+      return;
+
+#if defined(PNG_WRITE_USER_TRANSFORM_SUPPORTED)
+   if (png_ptr->transformations & PNG_USER_TRANSFORM)
+      if(png_ptr->write_user_transform_fn != NULL)
+        (*(png_ptr->write_user_transform_fn)) /* user write transform function */
+          (png_ptr,                    /* png_ptr */
+           &(png_ptr->row_info),       /* row_info:     */
+             /*  png_uint_32 width;          width of row */
+             /*  png_uint_32 rowbytes;       number of bytes in row */
+             /*  png_byte color_type;        color type of pixels */
+             /*  png_byte bit_depth;         bit depth of samples */
+             /*  png_byte channels;          number of channels (1-4) */
+             /*  png_byte pixel_depth;       bits per pixel (depth*channels) */
+           png_ptr->row_buf + 1);      /* start of pixel data for row */
+#endif
+#if defined(PNG_WRITE_FILLER_SUPPORTED)
+   if (png_ptr->transformations & PNG_FILLER)
+      png_do_strip_filler(&(png_ptr->row_info), png_ptr->row_buf + 1,
+         png_ptr->flags);
+#endif
+#if defined(PNG_WRITE_PACKSWAP_SUPPORTED)
+   if (png_ptr->transformations & PNG_PACKSWAP)
+      png_do_packswap(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+#if defined(PNG_WRITE_PACK_SUPPORTED)
+   if (png_ptr->transformations & PNG_PACK)
+      png_do_pack(&(png_ptr->row_info), png_ptr->row_buf + 1,
+         (png_uint_32)png_ptr->bit_depth);
+#endif
+#if defined(PNG_WRITE_SWAP_SUPPORTED)
+   if (png_ptr->transformations & PNG_SWAP_BYTES)
+      png_do_swap(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+#if defined(PNG_WRITE_SHIFT_SUPPORTED)
+   if (png_ptr->transformations & PNG_SHIFT)
+      png_do_shift(&(png_ptr->row_info), png_ptr->row_buf + 1,
+         &(png_ptr->shift));
+#endif
+#if defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
+   if (png_ptr->transformations & PNG_SWAP_ALPHA)
+      png_do_write_swap_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+#if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
+   if (png_ptr->transformations & PNG_INVERT_ALPHA)
+      png_do_write_invert_alpha(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+#if defined(PNG_WRITE_BGR_SUPPORTED)
+   if (png_ptr->transformations & PNG_BGR)
+      png_do_bgr(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+#if defined(PNG_WRITE_INVERT_SUPPORTED)
+   if (png_ptr->transformations & PNG_INVERT_MONO)
+      png_do_invert(&(png_ptr->row_info), png_ptr->row_buf + 1);
+#endif
+}
+
+#if defined(PNG_WRITE_PACK_SUPPORTED)
+/* Pack pixels into bytes.  Pass the true bit depth in bit_depth.  The
+ * row_info bit depth should be 8 (one pixel per byte).  The channels
+ * should be 1 (this only happens on grayscale and paletted images).
+ */
+void /* PRIVATE */
+png_do_pack(png_row_infop row_info, png_bytep row, png_uint_32 bit_depth)
+{
+   png_debug(1, "in png_do_pack\n");
+   if (row_info->bit_depth == 8 &&
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+       row != NULL && row_info != NULL &&
+#endif
+      row_info->channels == 1)
+   {
+      switch ((int)bit_depth)
+      {
+         case 1:
+         {
+            png_bytep sp, dp;
+            int mask, v;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            sp = row;
+            dp = row;
+            mask = 0x80;
+            v = 0;
+
+            for (i = 0; i < row_width; i++)
+            {
+               if (*sp != 0)
+                  v |= mask;
+               sp++;
+               if (mask > 1)
+                  mask >>= 1;
+               else
+               {
+                  mask = 0x80;
+                  *dp = (png_byte)v;
+                  dp++;
+                  v = 0;
+               }
+            }
+            if (mask != 0x80)
+               *dp = (png_byte)v;
+            break;
+         }
+         case 2:
+         {
+            png_bytep sp, dp;
+            int shift, v;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            sp = row;
+            dp = row;
+            shift = 6;
+            v = 0;
+            for (i = 0; i < row_width; i++)
+            {
+               png_byte value;
+
+               value = (png_byte)(*sp & 0x03);
+               v |= (value << shift);
+               if (shift == 0)
+               {
+                  shift = 6;
+                  *dp = (png_byte)v;
+                  dp++;
+                  v = 0;
+               }
+               else
+                  shift -= 2;
+               sp++;
+            }
+            if (shift != 6)
+               *dp = (png_byte)v;
+            break;
+         }
+         case 4:
+         {
+            png_bytep sp, dp;
+            int shift, v;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            sp = row;
+            dp = row;
+            shift = 4;
+            v = 0;
+            for (i = 0; i < row_width; i++)
+            {
+               png_byte value;
+
+               value = (png_byte)(*sp & 0x0f);
+               v |= (value << shift);
+
+               if (shift == 0)
+               {
+                  shift = 4;
+                  *dp = (png_byte)v;
+                  dp++;
+                  v = 0;
+               }
+               else
+                  shift -= 4;
+
+               sp++;
+            }
+            if (shift != 4)
+               *dp = (png_byte)v;
+            break;
+         }
+      }
+      row_info->bit_depth = (png_byte)bit_depth;
+      row_info->pixel_depth = (png_byte)(bit_depth * row_info->channels);
+      row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
+         row_info->width);
+   }
+}
+#endif
+
+#if defined(PNG_WRITE_SHIFT_SUPPORTED)
+/* Shift pixel values to take advantage of whole range.  Pass the
+ * true number of bits in bit_depth.  The row should be packed
+ * according to row_info->bit_depth.  Thus, if you had a row of
+ * bit depth 4, but the pixels only had values from 0 to 7, you
+ * would pass 3 as bit_depth, and this routine would translate the
+ * data to 0 to 15.
+ */
+void /* PRIVATE */
+png_do_shift(png_row_infop row_info, png_bytep row, png_color_8p bit_depth)
+{
+   png_debug(1, "in png_do_shift\n");
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+   if (row != NULL && row_info != NULL &&
+#else
+   if (
+#endif
+      row_info->color_type != PNG_COLOR_TYPE_PALETTE)
+   {
+      int shift_start[4], shift_dec[4];
+      int channels = 0;
+
+      if (row_info->color_type & PNG_COLOR_MASK_COLOR)
+      {
+         shift_start[channels] = row_info->bit_depth - bit_depth->red;
+         shift_dec[channels] = bit_depth->red;
+         channels++;
+         shift_start[channels] = row_info->bit_depth - bit_depth->green;
+         shift_dec[channels] = bit_depth->green;
+         channels++;
+         shift_start[channels] = row_info->bit_depth - bit_depth->blue;
+         shift_dec[channels] = bit_depth->blue;
+         channels++;
+      }
+      else
+      {
+         shift_start[channels] = row_info->bit_depth - bit_depth->gray;
+         shift_dec[channels] = bit_depth->gray;
+         channels++;
+      }
+      if (row_info->color_type & PNG_COLOR_MASK_ALPHA)
+      {
+         shift_start[channels] = row_info->bit_depth - bit_depth->alpha;
+         shift_dec[channels] = bit_depth->alpha;
+         channels++;
+      }
+
+      /* with low row depths, could only be grayscale, so one channel */
+      if (row_info->bit_depth < 8)
+      {
+         png_bytep bp = row;
+         png_uint_32 i;
+         png_byte mask;
+         png_uint_32 row_bytes = row_info->rowbytes;
+
+         if (bit_depth->gray == 1 && row_info->bit_depth == 2)
+            mask = 0x55;
+         else if (row_info->bit_depth == 4 && bit_depth->gray == 3)
+            mask = 0x11;
+         else
+            mask = 0xff;
+
+         for (i = 0; i < row_bytes; i++, bp++)
+         {
+            png_uint_16 v;
+            int j;
+
+            v = *bp;
+            *bp = 0;
+            for (j = shift_start[0]; j > -shift_dec[0]; j -= shift_dec[0])
+            {
+               if (j > 0)
+                  *bp |= (png_byte)((v << j) & 0xff);
+               else
+                  *bp |= (png_byte)((v >> (-j)) & mask);
+            }
+         }
+      }
+      else if (row_info->bit_depth == 8)
+      {
+         png_bytep bp = row;
+         png_uint_32 i;
+         png_uint_32 istop = channels * row_info->width;
+
+         for (i = 0; i < istop; i++, bp++)
+         {
+
+            png_uint_16 v;
+            int j;
+            int c = (int)(i%channels);
+
+            v = *bp;
+            *bp = 0;
+            for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
+            {
+               if (j > 0)
+                  *bp |= (png_byte)((v << j) & 0xff);
+               else
+                  *bp |= (png_byte)((v >> (-j)) & 0xff);
+            }
+         }
+      }
+      else
+      {
+         png_bytep bp;
+         png_uint_32 i;
+         png_uint_32 istop = channels * row_info->width;
+
+         for (bp = row, i = 0; i < istop; i++)
+         {
+            int c = (int)(i%channels);
+            png_uint_16 value, v;
+            int j;
+
+            v = (png_uint_16)(((png_uint_16)(*bp) << 8) + *(bp + 1));
+            value = 0;
+            for (j = shift_start[c]; j > -shift_dec[c]; j -= shift_dec[c])
+            {
+               if (j > 0)
+                  value |= (png_uint_16)((v << j) & (png_uint_16)0xffff);
+               else
+                  value |= (png_uint_16)((v >> (-j)) & (png_uint_16)0xffff);
+            }
+            *bp++ = (png_byte)(value >> 8);
+            *bp++ = (png_byte)(value & 0xff);
+         }
+      }
+   }
+}
+#endif
+
+#if defined(PNG_WRITE_SWAP_ALPHA_SUPPORTED)
+void /* PRIVATE */
+png_do_write_swap_alpha(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_write_swap_alpha\n");
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+   if (row != NULL && row_info != NULL)
+#endif
+   {
+      if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+      {
+         /* This converts from ARGB to RGBA */
+         if (row_info->bit_depth == 8)
+         {
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               png_byte save = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = save;
+            }
+         }
+         /* This converts from AARRGGBB to RRGGBBAA */
+         else
+         {
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               png_byte save[2];
+               save[0] = *(sp++);
+               save[1] = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = save[0];
+               *(dp++) = save[1];
+            }
+         }
+      }
+      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      {
+         /* This converts from AG to GA */
+         if (row_info->bit_depth == 8)
+         {
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               png_byte save = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = save;
+            }
+         }
+         /* This converts from AAGG to GGAA */
+         else
+         {
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               png_byte save[2];
+               save[0] = *(sp++);
+               save[1] = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = save[0];
+               *(dp++) = save[1];
+            }
+         }
+      }
+   }
+}
+#endif
+
+#if defined(PNG_WRITE_INVERT_ALPHA_SUPPORTED)
+void /* PRIVATE */
+png_do_write_invert_alpha(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_write_invert_alpha\n");
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+   if (row != NULL && row_info != NULL)
+#endif
+   {
+      if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+      {
+         /* This inverts the alpha channel in RGBA */
+         if (row_info->bit_depth == 8)
+         {
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               /* does nothing
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               */
+               sp+=3; dp = sp;
+               *(dp++) = (png_byte)(255 - *(sp++));
+            }
+         }
+         /* This inverts the alpha channel in RRGGBBAA */
+         else
+         {
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               /* does nothing
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               */
+               sp+=6; dp = sp;
+               *(dp++) = (png_byte)(255 - *(sp++));
+               *(dp++) = (png_byte)(255 - *(sp++));
+            }
+         }
+      }
+      else if (row_info->color_type == PNG_COLOR_TYPE_GRAY_ALPHA)
+      {
+         /* This inverts the alpha channel in GA */
+         if (row_info->bit_depth == 8)
+         {
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               *(dp++) = *(sp++);
+               *(dp++) = (png_byte)(255 - *(sp++));
+            }
+         }
+         /* This inverts the alpha channel in GGAA */
+         else
+         {
+            png_bytep sp, dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            for (i = 0, sp = dp = row; i < row_width; i++)
+            {
+               /* does nothing
+               *(dp++) = *(sp++);
+               *(dp++) = *(sp++);
+               */
+               sp+=2; dp = sp;
+               *(dp++) = (png_byte)(255 - *(sp++));
+               *(dp++) = (png_byte)(255 - *(sp++));
+            }
+         }
+      }
+   }
+}
+#endif
+
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
+/* undoes intrapixel differencing  */
+void /* PRIVATE */
+png_do_write_intrapixel(png_row_infop row_info, png_bytep row)
+{
+   png_debug(1, "in png_do_write_intrapixel\n");
+   if (
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+       row != NULL && row_info != NULL &&
+#endif
+       (row_info->color_type & PNG_COLOR_MASK_COLOR))
+   {
+      int bytes_per_pixel;
+      png_uint_32 row_width = row_info->width;
+      if (row_info->bit_depth == 8)
+      {
+         png_bytep rp;
+         png_uint_32 i;
+
+         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+            bytes_per_pixel = 3;
+         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+            bytes_per_pixel = 4;
+         else
+            return;
+
+         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
+         {
+            *(rp)   = (png_byte)((*rp     - *(rp+1))&0xff);
+            *(rp+2) = (png_byte)((*(rp+2) - *(rp+1))&0xff);
+         }
+      }
+      else if (row_info->bit_depth == 16)
+      {
+         png_bytep rp;
+         png_uint_32 i;
+
+         if (row_info->color_type == PNG_COLOR_TYPE_RGB)
+            bytes_per_pixel = 6;
+         else if (row_info->color_type == PNG_COLOR_TYPE_RGB_ALPHA)
+            bytes_per_pixel = 8;
+         else
+            return;
+
+         for (i = 0, rp = row; i < row_width; i++, rp += bytes_per_pixel)
+         {
+            png_uint_32 s0   = (*(rp  ) << 8) | *(rp+1);
+            png_uint_32 s1   = (*(rp+2) << 8) | *(rp+3);
+            png_uint_32 s2   = (*(rp+4) << 8) | *(rp+5);
+            png_uint_32 red  = (png_uint_32)((s0-s1) & 0xffffL);
+            png_uint_32 blue = (png_uint_32)((s2-s1) & 0xffffL);
+            *(rp  ) = (png_byte)((red >> 8) & 0xff);
+            *(rp+1) = (png_byte)(red & 0xff);
+            *(rp+4) = (png_byte)((blue >> 8) & 0xff);
+            *(rp+5) = (png_byte)(blue & 0xff);
+         }
+      }
+   }
+}
+#endif /* PNG_MNG_FEATURES_SUPPORTED */
+#endif /* PNG_WRITE_SUPPORTED */
diff --git a/distrib/libpng-1.2.19/pngwutil.c b/distrib/libpng-1.2.19/pngwutil.c
new file mode 100644
index 0000000..849ee7d
--- /dev/null
+++ b/distrib/libpng-1.2.19/pngwutil.c
@@ -0,0 +1,2782 @@
+
+/* pngwutil.c - utilities to write a PNG file
+ *
+ * Last changed in libpng 1.2.19 August 18, 2007
+ * For conditions of distribution and use, see copyright notice in png.h
+ * Copyright (c) 1998-2007 Glenn Randers-Pehrson
+ * (Version 0.96 Copyright (c) 1996, 1997 Andreas Dilger)
+ * (Version 0.88 Copyright (c) 1995, 1996 Guy Eric Schalnat, Group 42, Inc.)
+ */
+
+#define PNG_INTERNAL
+#include "png.h"
+#ifdef PNG_WRITE_SUPPORTED
+
+/* Place a 32-bit number into a buffer in PNG byte order.  We work
+ * with unsigned numbers for convenience, although one supported
+ * ancillary chunk uses signed (two's complement) numbers.
+ */
+void PNGAPI
+png_save_uint_32(png_bytep buf, png_uint_32 i)
+{
+   buf[0] = (png_byte)((i >> 24) & 0xff);
+   buf[1] = (png_byte)((i >> 16) & 0xff);
+   buf[2] = (png_byte)((i >> 8) & 0xff);
+   buf[3] = (png_byte)(i & 0xff);
+}
+
+/* The png_save_int_32 function assumes integers are stored in two's
+ * complement format.  If this isn't the case, then this routine needs to
+ * be modified to write data in two's complement format.
+ */
+void PNGAPI
+png_save_int_32(png_bytep buf, png_int_32 i)
+{
+   buf[0] = (png_byte)((i >> 24) & 0xff);
+   buf[1] = (png_byte)((i >> 16) & 0xff);
+   buf[2] = (png_byte)((i >> 8) & 0xff);
+   buf[3] = (png_byte)(i & 0xff);
+}
+
+/* Place a 16-bit number into a buffer in PNG byte order.
+ * The parameter is declared unsigned int, not png_uint_16,
+ * just to avoid potential problems on pre-ANSI C compilers.
+ */
+void PNGAPI
+png_save_uint_16(png_bytep buf, unsigned int i)
+{
+   buf[0] = (png_byte)((i >> 8) & 0xff);
+   buf[1] = (png_byte)(i & 0xff);
+}
+
+/* Write a PNG chunk all at once.  The type is an array of ASCII characters
+ * representing the chunk name.  The array must be at least 4 bytes in
+ * length, and does not need to be null terminated.  To be safe, pass the
+ * pre-defined chunk names here, and if you need a new one, define it
+ * where the others are defined.  The length is the length of the data.
+ * All the data must be present.  If that is not possible, use the
+ * png_write_chunk_start(), png_write_chunk_data(), and png_write_chunk_end()
+ * functions instead.
+ */
+void PNGAPI
+png_write_chunk(png_structp png_ptr, png_bytep chunk_name,
+   png_bytep data, png_size_t length)
+{
+   if(png_ptr == NULL) return;
+   png_write_chunk_start(png_ptr, chunk_name, (png_uint_32)length);
+   png_write_chunk_data(png_ptr, data, length);
+   png_write_chunk_end(png_ptr);
+}
+
+/* Write the start of a PNG chunk.  The type is the chunk type.
+ * The total_length is the sum of the lengths of all the data you will be
+ * passing in png_write_chunk_data().
+ */
+void PNGAPI
+png_write_chunk_start(png_structp png_ptr, png_bytep chunk_name,
+   png_uint_32 length)
+{
+   png_byte buf[4];
+   png_debug2(0, "Writing %s chunk (%lu bytes)\n", chunk_name, length);
+   if(png_ptr == NULL) return;
+
+   /* write the length */
+   png_save_uint_32(buf, length);
+   png_write_data(png_ptr, buf, (png_size_t)4);
+
+   /* write the chunk name */
+   png_write_data(png_ptr, chunk_name, (png_size_t)4);
+   /* reset the crc and run it over the chunk name */
+   png_reset_crc(png_ptr);
+   png_calculate_crc(png_ptr, chunk_name, (png_size_t)4);
+}
+
+/* Write the data of a PNG chunk started with png_write_chunk_start().
+ * Note that multiple calls to this function are allowed, and that the
+ * sum of the lengths from these calls *must* add up to the total_length
+ * given to png_write_chunk_start().
+ */
+void PNGAPI
+png_write_chunk_data(png_structp png_ptr, png_bytep data, png_size_t length)
+{
+   /* write the data, and run the CRC over it */
+   if(png_ptr == NULL) return;
+   if (data != NULL && length > 0)
+   {
+      png_calculate_crc(png_ptr, data, length);
+      png_write_data(png_ptr, data, length);
+   }
+}
+
+/* Finish a chunk started with png_write_chunk_start(). */
+void PNGAPI
+png_write_chunk_end(png_structp png_ptr)
+{
+   png_byte buf[4];
+
+   if(png_ptr == NULL) return;
+
+   /* write the crc */
+   png_save_uint_32(buf, png_ptr->crc);
+
+   png_write_data(png_ptr, buf, (png_size_t)4);
+}
+
+/* Simple function to write the signature.  If we have already written
+ * the magic bytes of the signature, or more likely, the PNG stream is
+ * being embedded into another stream and doesn't need its own signature,
+ * we should call png_set_sig_bytes() to tell libpng how many of the
+ * bytes have already been written.
+ */
+void /* PRIVATE */
+png_write_sig(png_structp png_ptr)
+{
+   png_byte png_signature[8] = {137, 80, 78, 71, 13, 10, 26, 10};
+   /* write the rest of the 8 byte signature */
+   png_write_data(png_ptr, &png_signature[png_ptr->sig_bytes],
+      (png_size_t)8 - png_ptr->sig_bytes);
+   if(png_ptr->sig_bytes < 3)
+      png_ptr->mode |= PNG_HAVE_PNG_SIGNATURE;
+}
+
+#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_iCCP_SUPPORTED)
+/*
+ * This pair of functions encapsulates the operation of (a) compressing a
+ * text string, and (b) issuing it later as a series of chunk data writes.
+ * The compression_state structure is shared context for these functions
+ * set up by the caller in order to make the whole mess thread-safe.
+ */
+
+typedef struct
+{
+    char *input;   /* the uncompressed input data */
+    int input_len;   /* its length */
+    int num_output_ptr; /* number of output pointers used */
+    int max_output_ptr; /* size of output_ptr */
+    png_charpp output_ptr; /* array of pointers to output */
+} compression_state;
+
+/* compress given text into storage in the png_ptr structure */
+static int /* PRIVATE */
+png_text_compress(png_structp png_ptr,
+        png_charp text, png_size_t text_len, int compression,
+        compression_state *comp)
+{
+   int ret;
+
+   comp->num_output_ptr = 0;
+   comp->max_output_ptr = 0;
+   comp->output_ptr = NULL;
+   comp->input = NULL;
+   comp->input_len = 0;
+
+   /* we may just want to pass the text right through */
+   if (compression == PNG_TEXT_COMPRESSION_NONE)
+   {
+       comp->input = text;
+       comp->input_len = text_len;
+       return((int)text_len);
+   }
+
+   if (compression >= PNG_TEXT_COMPRESSION_LAST)
+   {
+#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
+      char msg[50];
+      png_snprintf(msg, 50, "Unknown compression type %d", compression);
+      png_warning(png_ptr, msg);
+#else
+      png_warning(png_ptr, "Unknown compression type");
+#endif
+   }
+
+   /* We can't write the chunk until we find out how much data we have,
+    * which means we need to run the compressor first and save the
+    * output.  This shouldn't be a problem, as the vast majority of
+    * comments should be reasonable, but we will set up an array of
+    * malloc'd pointers to be sure.
+    *
+    * If we knew the application was well behaved, we could simplify this
+    * greatly by assuming we can always malloc an output buffer large
+    * enough to hold the compressed text ((1001 * text_len / 1000) + 12)
+    * and malloc this directly.  The only time this would be a bad idea is
+    * if we can't malloc more than 64K and we have 64K of random input
+    * data, or if the input string is incredibly large (although this
+    * wouldn't cause a failure, just a slowdown due to swapping).
+    */
+
+   /* set up the compression buffers */
+   png_ptr->zstream.avail_in = (uInt)text_len;
+   png_ptr->zstream.next_in = (Bytef *)text;
+   png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+   png_ptr->zstream.next_out = (Bytef *)png_ptr->zbuf;
+
+   /* this is the same compression loop as in png_write_row() */
+   do
+   {
+      /* compress the data */
+      ret = deflate(&png_ptr->zstream, Z_NO_FLUSH);
+      if (ret != Z_OK)
+      {
+         /* error */
+         if (png_ptr->zstream.msg != NULL)
+            png_error(png_ptr, png_ptr->zstream.msg);
+         else
+            png_error(png_ptr, "zlib error");
+      }
+      /* check to see if we need more room */
+      if (!(png_ptr->zstream.avail_out))
+      {
+         /* make sure the output array has room */
+         if (comp->num_output_ptr >= comp->max_output_ptr)
+         {
+            int old_max;
+
+            old_max = comp->max_output_ptr;
+            comp->max_output_ptr = comp->num_output_ptr + 4;
+            if (comp->output_ptr != NULL)
+            {
+               png_charpp old_ptr;
+
+               old_ptr = comp->output_ptr;
+               comp->output_ptr = (png_charpp)png_malloc(png_ptr,
+                  (png_uint_32)(comp->max_output_ptr *
+                  png_sizeof (png_charpp)));
+               png_memcpy(comp->output_ptr, old_ptr, old_max
+                  * png_sizeof (png_charp));
+               png_free(png_ptr, old_ptr);
+            }
+            else
+               comp->output_ptr = (png_charpp)png_malloc(png_ptr,
+                  (png_uint_32)(comp->max_output_ptr *
+                  png_sizeof (png_charp)));
+         }
+
+         /* save the data */
+         comp->output_ptr[comp->num_output_ptr] = (png_charp)png_malloc(png_ptr,
+            (png_uint_32)png_ptr->zbuf_size);
+         png_memcpy(comp->output_ptr[comp->num_output_ptr], png_ptr->zbuf,
+            png_ptr->zbuf_size);
+         comp->num_output_ptr++;
+
+         /* and reset the buffer */
+         png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+         png_ptr->zstream.next_out = png_ptr->zbuf;
+      }
+   /* continue until we don't have any more to compress */
+   } while (png_ptr->zstream.avail_in);
+
+   /* finish the compression */
+   do
+   {
+      /* tell zlib we are finished */
+      ret = deflate(&png_ptr->zstream, Z_FINISH);
+
+      if (ret == Z_OK)
+      {
+         /* check to see if we need more room */
+         if (!(png_ptr->zstream.avail_out))
+         {
+            /* check to make sure our output array has room */
+            if (comp->num_output_ptr >= comp->max_output_ptr)
+            {
+               int old_max;
+
+               old_max = comp->max_output_ptr;
+               comp->max_output_ptr = comp->num_output_ptr + 4;
+               if (comp->output_ptr != NULL)
+               {
+                  png_charpp old_ptr;
+
+                  old_ptr = comp->output_ptr;
+                  /* This could be optimized to realloc() */
+                  comp->output_ptr = (png_charpp)png_malloc(png_ptr,
+                     (png_uint_32)(comp->max_output_ptr *
+                     png_sizeof (png_charpp)));
+                  png_memcpy(comp->output_ptr, old_ptr,
+                     old_max * png_sizeof (png_charp));
+                  png_free(png_ptr, old_ptr);
+               }
+               else
+                  comp->output_ptr = (png_charpp)png_malloc(png_ptr,
+                     (png_uint_32)(comp->max_output_ptr *
+                     png_sizeof (png_charp)));
+            }
+
+            /* save off the data */
+            comp->output_ptr[comp->num_output_ptr] =
+               (png_charp)png_malloc(png_ptr, (png_uint_32)png_ptr->zbuf_size);
+            png_memcpy(comp->output_ptr[comp->num_output_ptr], png_ptr->zbuf,
+               png_ptr->zbuf_size);
+            comp->num_output_ptr++;
+
+            /* and reset the buffer pointers */
+            png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+            png_ptr->zstream.next_out = png_ptr->zbuf;
+         }
+      }
+      else if (ret != Z_STREAM_END)
+      {
+         /* we got an error */
+         if (png_ptr->zstream.msg != NULL)
+            png_error(png_ptr, png_ptr->zstream.msg);
+         else
+            png_error(png_ptr, "zlib error");
+      }
+   } while (ret != Z_STREAM_END);
+
+   /* text length is number of buffers plus last buffer */
+   text_len = png_ptr->zbuf_size * comp->num_output_ptr;
+   if (png_ptr->zstream.avail_out < png_ptr->zbuf_size)
+      text_len += png_ptr->zbuf_size - (png_size_t)png_ptr->zstream.avail_out;
+
+   return((int)text_len);
+}
+
+/* ship the compressed text out via chunk writes */
+static void /* PRIVATE */
+png_write_compressed_data_out(png_structp png_ptr, compression_state *comp)
+{
+   int i;
+
+   /* handle the no-compression case */
+   if (comp->input)
+   {
+       png_write_chunk_data(png_ptr, (png_bytep)comp->input,
+                            (png_size_t)comp->input_len);
+       return;
+   }
+
+   /* write saved output buffers, if any */
+   for (i = 0; i < comp->num_output_ptr; i++)
+   {
+      png_write_chunk_data(png_ptr,(png_bytep)comp->output_ptr[i],
+         png_ptr->zbuf_size);
+      png_free(png_ptr, comp->output_ptr[i]);
+      comp->output_ptr[i]=NULL;
+   }
+   if (comp->max_output_ptr != 0)
+      png_free(png_ptr, comp->output_ptr);
+      comp->output_ptr=NULL;
+   /* write anything left in zbuf */
+   if (png_ptr->zstream.avail_out < (png_uint_32)png_ptr->zbuf_size)
+      png_write_chunk_data(png_ptr, png_ptr->zbuf,
+         png_ptr->zbuf_size - png_ptr->zstream.avail_out);
+
+   /* reset zlib for another zTXt/iTXt or image data */
+   deflateReset(&png_ptr->zstream);
+   png_ptr->zstream.data_type = Z_BINARY;
+}
+#endif
+
+/* Write the IHDR chunk, and update the png_struct with the necessary
+ * information.  Note that the rest of this code depends upon this
+ * information being correct.
+ */
+void /* PRIVATE */
+png_write_IHDR(png_structp png_ptr, png_uint_32 width, png_uint_32 height,
+   int bit_depth, int color_type, int compression_type, int filter_type,
+   int interlace_type)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_IHDR;
+#endif
+   png_byte buf[13]; /* buffer to store the IHDR info */
+
+   png_debug(1, "in png_write_IHDR\n");
+   /* Check that we have valid input data from the application info */
+   switch (color_type)
+   {
+      case PNG_COLOR_TYPE_GRAY:
+         switch (bit_depth)
+         {
+            case 1:
+            case 2:
+            case 4:
+            case 8:
+            case 16: png_ptr->channels = 1; break;
+            default: png_error(png_ptr,"Invalid bit depth for grayscale image");
+         }
+         break;
+      case PNG_COLOR_TYPE_RGB:
+         if (bit_depth != 8 && bit_depth != 16)
+            png_error(png_ptr, "Invalid bit depth for RGB image");
+         png_ptr->channels = 3;
+         break;
+      case PNG_COLOR_TYPE_PALETTE:
+         switch (bit_depth)
+         {
+            case 1:
+            case 2:
+            case 4:
+            case 8: png_ptr->channels = 1; break;
+            default: png_error(png_ptr, "Invalid bit depth for paletted image");
+         }
+         break;
+      case PNG_COLOR_TYPE_GRAY_ALPHA:
+         if (bit_depth != 8 && bit_depth != 16)
+            png_error(png_ptr, "Invalid bit depth for grayscale+alpha image");
+         png_ptr->channels = 2;
+         break;
+      case PNG_COLOR_TYPE_RGB_ALPHA:
+         if (bit_depth != 8 && bit_depth != 16)
+            png_error(png_ptr, "Invalid bit depth for RGBA image");
+         png_ptr->channels = 4;
+         break;
+      default:
+         png_error(png_ptr, "Invalid image color type specified");
+   }
+
+   if (compression_type != PNG_COMPRESSION_TYPE_BASE)
+   {
+      png_warning(png_ptr, "Invalid compression type specified");
+      compression_type = PNG_COMPRESSION_TYPE_BASE;
+   }
+
+   /* Write filter_method 64 (intrapixel differencing) only if
+    * 1. Libpng was compiled with PNG_MNG_FEATURES_SUPPORTED and
+    * 2. Libpng did not write a PNG signature (this filter_method is only
+    *    used in PNG datastreams that are embedded in MNG datastreams) and
+    * 3. The application called png_permit_mng_features with a mask that
+    *    included PNG_FLAG_MNG_FILTER_64 and
+    * 4. The filter_method is 64 and
+    * 5. The color_type is RGB or RGBA
+    */
+   if (
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
+      !((png_ptr->mng_features_permitted & PNG_FLAG_MNG_FILTER_64) &&
+      ((png_ptr->mode&PNG_HAVE_PNG_SIGNATURE) == 0) &&
+      (color_type == PNG_COLOR_TYPE_RGB ||
+       color_type == PNG_COLOR_TYPE_RGB_ALPHA) &&
+      (filter_type == PNG_INTRAPIXEL_DIFFERENCING)) &&
+#endif
+      filter_type != PNG_FILTER_TYPE_BASE)
+   {
+      png_warning(png_ptr, "Invalid filter type specified");
+      filter_type = PNG_FILTER_TYPE_BASE;
+   }
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+   if (interlace_type != PNG_INTERLACE_NONE &&
+      interlace_type != PNG_INTERLACE_ADAM7)
+   {
+      png_warning(png_ptr, "Invalid interlace type specified");
+      interlace_type = PNG_INTERLACE_ADAM7;
+   }
+#else
+   interlace_type=PNG_INTERLACE_NONE;
+#endif
+
+   /* save off the relevent information */
+   png_ptr->bit_depth = (png_byte)bit_depth;
+   png_ptr->color_type = (png_byte)color_type;
+   png_ptr->interlaced = (png_byte)interlace_type;
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
+   png_ptr->filter_type = (png_byte)filter_type;
+#endif
+   png_ptr->compression_type = (png_byte)compression_type;
+   png_ptr->width = width;
+   png_ptr->height = height;
+
+   png_ptr->pixel_depth = (png_byte)(bit_depth * png_ptr->channels);
+   png_ptr->rowbytes = PNG_ROWBYTES(png_ptr->pixel_depth, width);
+   /* set the usr info, so any transformations can modify it */
+   png_ptr->usr_width = png_ptr->width;
+   png_ptr->usr_bit_depth = png_ptr->bit_depth;
+   png_ptr->usr_channels = png_ptr->channels;
+
+   /* pack the header information into the buffer */
+   png_save_uint_32(buf, width);
+   png_save_uint_32(buf + 4, height);
+   buf[8] = (png_byte)bit_depth;
+   buf[9] = (png_byte)color_type;
+   buf[10] = (png_byte)compression_type;
+   buf[11] = (png_byte)filter_type;
+   buf[12] = (png_byte)interlace_type;
+
+   /* write the chunk */
+   png_write_chunk(png_ptr, (png_bytep)png_IHDR, buf, (png_size_t)13);
+
+   /* initialize zlib with PNG info */
+   png_ptr->zstream.zalloc = png_zalloc;
+   png_ptr->zstream.zfree = png_zfree;
+   png_ptr->zstream.opaque = (voidpf)png_ptr;
+   if (!(png_ptr->do_filter))
+   {
+      if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE ||
+         png_ptr->bit_depth < 8)
+         png_ptr->do_filter = PNG_FILTER_NONE;
+      else
+         png_ptr->do_filter = PNG_ALL_FILTERS;
+   }
+   if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_STRATEGY))
+   {
+      if (png_ptr->do_filter != PNG_FILTER_NONE)
+         png_ptr->zlib_strategy = Z_FILTERED;
+      else
+         png_ptr->zlib_strategy = Z_DEFAULT_STRATEGY;
+   }
+   if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_LEVEL))
+      png_ptr->zlib_level = Z_DEFAULT_COMPRESSION;
+   if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_MEM_LEVEL))
+      png_ptr->zlib_mem_level = 8;
+   if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_WINDOW_BITS))
+      png_ptr->zlib_window_bits = 15;
+   if (!(png_ptr->flags & PNG_FLAG_ZLIB_CUSTOM_METHOD))
+      png_ptr->zlib_method = 8;
+   if (deflateInit2(&png_ptr->zstream, png_ptr->zlib_level,
+      png_ptr->zlib_method, png_ptr->zlib_window_bits,
+      png_ptr->zlib_mem_level, png_ptr->zlib_strategy) != Z_OK)
+       png_error(png_ptr, "zlib failed to initialize compressor");
+   png_ptr->zstream.next_out = png_ptr->zbuf;
+   png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+   /* libpng is not interested in zstream.data_type */
+   /* set it to a predefined value, to avoid its evaluation inside zlib */
+   png_ptr->zstream.data_type = Z_BINARY;
+
+   png_ptr->mode = PNG_HAVE_IHDR;
+}
+
+/* write the palette.  We are careful not to trust png_color to be in the
+ * correct order for PNG, so people can redefine it to any convenient
+ * structure.
+ */
+void /* PRIVATE */
+png_write_PLTE(png_structp png_ptr, png_colorp palette, png_uint_32 num_pal)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_PLTE;
+#endif
+   png_uint_32 i;
+   png_colorp pal_ptr;
+   png_byte buf[3];
+
+   png_debug(1, "in png_write_PLTE\n");
+   if ((
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
+        !(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE) &&
+#endif
+        num_pal == 0) || num_pal > 256)
+   {
+     if (png_ptr->color_type == PNG_COLOR_TYPE_PALETTE)
+     {
+        png_error(png_ptr, "Invalid number of colors in palette");
+     }
+     else
+     {
+        png_warning(png_ptr, "Invalid number of colors in palette");
+        return;
+     }
+   }
+
+   if (!(png_ptr->color_type&PNG_COLOR_MASK_COLOR))
+   {
+      png_warning(png_ptr,
+        "Ignoring request to write a PLTE chunk in grayscale PNG");
+      return;
+   }
+
+   png_ptr->num_palette = (png_uint_16)num_pal;
+   png_debug1(3, "num_palette = %d\n", png_ptr->num_palette);
+
+   png_write_chunk_start(png_ptr, png_PLTE, num_pal * 3);
+#ifndef PNG_NO_POINTER_INDEXING
+   for (i = 0, pal_ptr = palette; i < num_pal; i++, pal_ptr++)
+   {
+      buf[0] = pal_ptr->red;
+      buf[1] = pal_ptr->green;
+      buf[2] = pal_ptr->blue;
+      png_write_chunk_data(png_ptr, buf, (png_size_t)3);
+   }
+#else
+   /* This is a little slower but some buggy compilers need to do this instead */
+   pal_ptr=palette;
+   for (i = 0; i < num_pal; i++)
+   {
+      buf[0] = pal_ptr[i].red;
+      buf[1] = pal_ptr[i].green;
+      buf[2] = pal_ptr[i].blue;
+      png_write_chunk_data(png_ptr, buf, (png_size_t)3);
+   }
+#endif
+   png_write_chunk_end(png_ptr);
+   png_ptr->mode |= PNG_HAVE_PLTE;
+}
+
+/* write an IDAT chunk */
+void /* PRIVATE */
+png_write_IDAT(png_structp png_ptr, png_bytep data, png_size_t length)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_IDAT;
+#endif
+   png_debug(1, "in png_write_IDAT\n");
+
+   /* Optimize the CMF field in the zlib stream. */
+   /* This hack of the zlib stream is compliant to the stream specification. */
+   if (!(png_ptr->mode & PNG_HAVE_IDAT) &&
+       png_ptr->compression_type == PNG_COMPRESSION_TYPE_BASE)
+   {
+      unsigned int z_cmf = data[0];  /* zlib compression method and flags */
+      if ((z_cmf & 0x0f) == 8 && (z_cmf & 0xf0) <= 0x70)
+      {
+         /* Avoid memory underflows and multiplication overflows. */
+         /* The conditions below are practically always satisfied;
+            however, they still must be checked. */
+         if (length >= 2 &&
+             png_ptr->height < 16384 && png_ptr->width < 16384)
+         {
+            png_uint_32 uncompressed_idat_size = png_ptr->height *
+               ((png_ptr->width *
+               png_ptr->channels * png_ptr->bit_depth + 15) >> 3);
+            unsigned int z_cinfo = z_cmf >> 4;
+            unsigned int half_z_window_size = 1 << (z_cinfo + 7);
+            while (uncompressed_idat_size <= half_z_window_size &&
+                   half_z_window_size >= 256)
+            {
+               z_cinfo--;
+               half_z_window_size >>= 1;
+            }
+            z_cmf = (z_cmf & 0x0f) | (z_cinfo << 4);
+            if (data[0] != (png_byte)z_cmf)
+            {
+               data[0] = (png_byte)z_cmf;
+               data[1] &= 0xe0;
+               data[1] += (png_byte)(0x1f - ((z_cmf << 8) + data[1]) % 0x1f);
+            }
+         }
+      }
+      else
+         png_error(png_ptr,
+            "Invalid zlib compression method or flags in IDAT");
+   }
+
+   png_write_chunk(png_ptr, (png_bytep)png_IDAT, data, length);
+   png_ptr->mode |= PNG_HAVE_IDAT;
+}
+
+/* write an IEND chunk */
+void /* PRIVATE */
+png_write_IEND(png_structp png_ptr)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_IEND;
+#endif
+   png_debug(1, "in png_write_IEND\n");
+   png_write_chunk(png_ptr, (png_bytep)png_IEND, png_bytep_NULL,
+     (png_size_t)0);
+   png_ptr->mode |= PNG_HAVE_IEND;
+}
+
+#if defined(PNG_WRITE_gAMA_SUPPORTED)
+/* write a gAMA chunk */
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+void /* PRIVATE */
+png_write_gAMA(png_structp png_ptr, double file_gamma)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_gAMA;
+#endif
+   png_uint_32 igamma;
+   png_byte buf[4];
+
+   png_debug(1, "in png_write_gAMA\n");
+   /* file_gamma is saved in 1/100,000ths */
+   igamma = (png_uint_32)(file_gamma * 100000.0 + 0.5);
+   png_save_uint_32(buf, igamma);
+   png_write_chunk(png_ptr, (png_bytep)png_gAMA, buf, (png_size_t)4);
+}
+#endif
+#ifdef PNG_FIXED_POINT_SUPPORTED
+void /* PRIVATE */
+png_write_gAMA_fixed(png_structp png_ptr, png_fixed_point file_gamma)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_gAMA;
+#endif
+   png_byte buf[4];
+
+   png_debug(1, "in png_write_gAMA\n");
+   /* file_gamma is saved in 1/100,000ths */
+   png_save_uint_32(buf, (png_uint_32)file_gamma);
+   png_write_chunk(png_ptr, (png_bytep)png_gAMA, buf, (png_size_t)4);
+}
+#endif
+#endif
+
+#if defined(PNG_WRITE_sRGB_SUPPORTED)
+/* write a sRGB chunk */
+void /* PRIVATE */
+png_write_sRGB(png_structp png_ptr, int srgb_intent)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_sRGB;
+#endif
+   png_byte buf[1];
+
+   png_debug(1, "in png_write_sRGB\n");
+   if(srgb_intent >= PNG_sRGB_INTENT_LAST)
+         png_warning(png_ptr,
+            "Invalid sRGB rendering intent specified");
+   buf[0]=(png_byte)srgb_intent;
+   png_write_chunk(png_ptr, (png_bytep)png_sRGB, buf, (png_size_t)1);
+}
+#endif
+
+#if defined(PNG_WRITE_iCCP_SUPPORTED)
+/* write an iCCP chunk */
+void /* PRIVATE */
+png_write_iCCP(png_structp png_ptr, png_charp name, int compression_type,
+   png_charp profile, int profile_len)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_iCCP;
+#endif
+   png_size_t name_len;
+   png_charp new_name;
+   compression_state comp;
+   int embedded_profile_len = 0;
+
+   png_debug(1, "in png_write_iCCP\n");
+
+   comp.num_output_ptr = 0;
+   comp.max_output_ptr = 0;
+   comp.output_ptr = NULL;
+   comp.input = NULL;
+   comp.input_len = 0;
+
+   if (name == NULL || (name_len = png_check_keyword(png_ptr, name,
+      &new_name)) == 0)
+   {
+      png_warning(png_ptr, "Empty keyword in iCCP chunk");
+      return;
+   }
+
+   if (compression_type != PNG_COMPRESSION_TYPE_BASE)
+      png_warning(png_ptr, "Unknown compression type in iCCP chunk");
+
+   if (profile == NULL)
+      profile_len = 0;
+
+   if (profile_len > 3)
+      embedded_profile_len =
+          ((*( (png_bytep)profile  ))<<24) |
+          ((*( (png_bytep)profile+1))<<16) |
+          ((*( (png_bytep)profile+2))<< 8) |
+          ((*( (png_bytep)profile+3))    );
+
+   if (profile_len < embedded_profile_len)
+     {
+        png_warning(png_ptr,
+          "Embedded profile length too large in iCCP chunk");
+        return;
+     }
+
+   if (profile_len > embedded_profile_len)
+     {
+        png_warning(png_ptr,
+          "Truncating profile to actual length in iCCP chunk");
+        profile_len = embedded_profile_len;
+     }
+
+   if (profile_len)
+       profile_len = png_text_compress(png_ptr, profile, (png_size_t)profile_len,
+          PNG_COMPRESSION_TYPE_BASE, &comp);
+
+   /* make sure we include the NULL after the name and the compression type */
+   png_write_chunk_start(png_ptr, png_iCCP,
+          (png_uint_32)name_len+profile_len+2);
+   new_name[name_len+1]=0x00;
+   png_write_chunk_data(png_ptr, (png_bytep)new_name, name_len + 2);
+
+   if (profile_len)
+      png_write_compressed_data_out(png_ptr, &comp);
+
+   png_write_chunk_end(png_ptr);
+   png_free(png_ptr, new_name);
+}
+#endif
+
+#if defined(PNG_WRITE_sPLT_SUPPORTED)
+/* write a sPLT chunk */
+void /* PRIVATE */
+png_write_sPLT(png_structp png_ptr, png_sPLT_tp spalette)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_sPLT;
+#endif
+   png_size_t name_len;
+   png_charp new_name;
+   png_byte entrybuf[10];
+   int entry_size = (spalette->depth == 8 ? 6 : 10);
+   int palette_size = entry_size * spalette->nentries;
+   png_sPLT_entryp ep;
+#ifdef PNG_NO_POINTER_INDEXING
+   int i;
+#endif
+
+   png_debug(1, "in png_write_sPLT\n");
+   if (spalette->name == NULL || (name_len = png_check_keyword(png_ptr,
+      spalette->name, &new_name))==0)
+   {
+      png_warning(png_ptr, "Empty keyword in sPLT chunk");
+      return;
+   }
+
+   /* make sure we include the NULL after the name */
+   png_write_chunk_start(png_ptr, png_sPLT,
+          (png_uint_32)(name_len + 2 + palette_size));
+   png_write_chunk_data(png_ptr, (png_bytep)new_name, name_len + 1);
+   png_write_chunk_data(png_ptr, (png_bytep)&spalette->depth, 1);
+
+   /* loop through each palette entry, writing appropriately */
+#ifndef PNG_NO_POINTER_INDEXING
+   for (ep = spalette->entries; ep<spalette->entries+spalette->nentries; ep++)
+   {
+       if (spalette->depth == 8)
+       {
+           entrybuf[0] = (png_byte)ep->red;
+           entrybuf[1] = (png_byte)ep->green;
+           entrybuf[2] = (png_byte)ep->blue;
+           entrybuf[3] = (png_byte)ep->alpha;
+           png_save_uint_16(entrybuf + 4, ep->frequency);
+       }
+       else
+       {
+           png_save_uint_16(entrybuf + 0, ep->red);
+           png_save_uint_16(entrybuf + 2, ep->green);
+           png_save_uint_16(entrybuf + 4, ep->blue);
+           png_save_uint_16(entrybuf + 6, ep->alpha);
+           png_save_uint_16(entrybuf + 8, ep->frequency);
+       }
+       png_write_chunk_data(png_ptr, entrybuf, (png_size_t)entry_size);
+   }
+#else
+   ep=spalette->entries;
+   for (i=0; i>spalette->nentries; i++)
+   {
+       if (spalette->depth == 8)
+       {
+           entrybuf[0] = (png_byte)ep[i].red;
+           entrybuf[1] = (png_byte)ep[i].green;
+           entrybuf[2] = (png_byte)ep[i].blue;
+           entrybuf[3] = (png_byte)ep[i].alpha;
+           png_save_uint_16(entrybuf + 4, ep[i].frequency);
+       }
+       else
+       {
+           png_save_uint_16(entrybuf + 0, ep[i].red);
+           png_save_uint_16(entrybuf + 2, ep[i].green);
+           png_save_uint_16(entrybuf + 4, ep[i].blue);
+           png_save_uint_16(entrybuf + 6, ep[i].alpha);
+           png_save_uint_16(entrybuf + 8, ep[i].frequency);
+       }
+       png_write_chunk_data(png_ptr, entrybuf, entry_size);
+   }
+#endif
+
+   png_write_chunk_end(png_ptr);
+   png_free(png_ptr, new_name);
+}
+#endif
+
+#if defined(PNG_WRITE_sBIT_SUPPORTED)
+/* write the sBIT chunk */
+void /* PRIVATE */
+png_write_sBIT(png_structp png_ptr, png_color_8p sbit, int color_type)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_sBIT;
+#endif
+   png_byte buf[4];
+   png_size_t size;
+
+   png_debug(1, "in png_write_sBIT\n");
+   /* make sure we don't depend upon the order of PNG_COLOR_8 */
+   if (color_type & PNG_COLOR_MASK_COLOR)
+   {
+      png_byte maxbits;
+
+      maxbits = (png_byte)(color_type==PNG_COLOR_TYPE_PALETTE ? 8 :
+                png_ptr->usr_bit_depth);
+      if (sbit->red == 0 || sbit->red > maxbits ||
+          sbit->green == 0 || sbit->green > maxbits ||
+          sbit->blue == 0 || sbit->blue > maxbits)
+      {
+         png_warning(png_ptr, "Invalid sBIT depth specified");
+         return;
+      }
+      buf[0] = sbit->red;
+      buf[1] = sbit->green;
+      buf[2] = sbit->blue;
+      size = 3;
+   }
+   else
+   {
+      if (sbit->gray == 0 || sbit->gray > png_ptr->usr_bit_depth)
+      {
+         png_warning(png_ptr, "Invalid sBIT depth specified");
+         return;
+      }
+      buf[0] = sbit->gray;
+      size = 1;
+   }
+
+   if (color_type & PNG_COLOR_MASK_ALPHA)
+   {
+      if (sbit->alpha == 0 || sbit->alpha > png_ptr->usr_bit_depth)
+      {
+         png_warning(png_ptr, "Invalid sBIT depth specified");
+         return;
+      }
+      buf[size++] = sbit->alpha;
+   }
+
+   png_write_chunk(png_ptr, (png_bytep)png_sBIT, buf, size);
+}
+#endif
+
+#if defined(PNG_WRITE_cHRM_SUPPORTED)
+/* write the cHRM chunk */
+#ifdef PNG_FLOATING_POINT_SUPPORTED
+void /* PRIVATE */
+png_write_cHRM(png_structp png_ptr, double white_x, double white_y,
+   double red_x, double red_y, double green_x, double green_y,
+   double blue_x, double blue_y)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_cHRM;
+#endif
+   png_byte buf[32];
+   png_uint_32 itemp;
+
+   png_debug(1, "in png_write_cHRM\n");
+   /* each value is saved in 1/100,000ths */
+   if (white_x < 0 || white_x > 0.8 || white_y < 0 || white_y > 0.8 ||
+       white_x + white_y > 1.0)
+   {
+      png_warning(png_ptr, "Invalid cHRM white point specified");
+#if !defined(PNG_NO_CONSOLE_IO)
+      fprintf(stderr,"white_x=%f, white_y=%f\n",white_x, white_y);
+#endif
+      return;
+   }
+   itemp = (png_uint_32)(white_x * 100000.0 + 0.5);
+   png_save_uint_32(buf, itemp);
+   itemp = (png_uint_32)(white_y * 100000.0 + 0.5);
+   png_save_uint_32(buf + 4, itemp);
+
+   if (red_x < 0 ||  red_y < 0 || red_x + red_y > 1.0)
+   {
+      png_warning(png_ptr, "Invalid cHRM red point specified");
+      return;
+   }
+   itemp = (png_uint_32)(red_x * 100000.0 + 0.5);
+   png_save_uint_32(buf + 8, itemp);
+   itemp = (png_uint_32)(red_y * 100000.0 + 0.5);
+   png_save_uint_32(buf + 12, itemp);
+
+   if (green_x < 0 || green_y < 0 || green_x + green_y > 1.0)
+   {
+      png_warning(png_ptr, "Invalid cHRM green point specified");
+      return;
+   }
+   itemp = (png_uint_32)(green_x * 100000.0 + 0.5);
+   png_save_uint_32(buf + 16, itemp);
+   itemp = (png_uint_32)(green_y * 100000.0 + 0.5);
+   png_save_uint_32(buf + 20, itemp);
+
+   if (blue_x < 0 || blue_y < 0 || blue_x + blue_y > 1.0)
+   {
+      png_warning(png_ptr, "Invalid cHRM blue point specified");
+      return;
+   }
+   itemp = (png_uint_32)(blue_x * 100000.0 + 0.5);
+   png_save_uint_32(buf + 24, itemp);
+   itemp = (png_uint_32)(blue_y * 100000.0 + 0.5);
+   png_save_uint_32(buf + 28, itemp);
+
+   png_write_chunk(png_ptr, (png_bytep)png_cHRM, buf, (png_size_t)32);
+}
+#endif
+#ifdef PNG_FIXED_POINT_SUPPORTED
+void /* PRIVATE */
+png_write_cHRM_fixed(png_structp png_ptr, png_fixed_point white_x,
+   png_fixed_point white_y, png_fixed_point red_x, png_fixed_point red_y,
+   png_fixed_point green_x, png_fixed_point green_y, png_fixed_point blue_x,
+   png_fixed_point blue_y)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_cHRM;
+#endif
+   png_byte buf[32];
+
+   png_debug(1, "in png_write_cHRM\n");
+   /* each value is saved in 1/100,000ths */
+   if (white_x > 80000L || white_y > 80000L || white_x + white_y > 100000L)
+   {
+      png_warning(png_ptr, "Invalid fixed cHRM white point specified");
+#if !defined(PNG_NO_CONSOLE_IO)
+      fprintf(stderr,"white_x=%ld, white_y=%ld\n",white_x, white_y);
+#endif
+      return;
+   }
+   png_save_uint_32(buf, (png_uint_32)white_x);
+   png_save_uint_32(buf + 4, (png_uint_32)white_y);
+
+   if (red_x + red_y > 100000L)
+   {
+      png_warning(png_ptr, "Invalid cHRM fixed red point specified");
+      return;
+   }
+   png_save_uint_32(buf + 8, (png_uint_32)red_x);
+   png_save_uint_32(buf + 12, (png_uint_32)red_y);
+
+   if (green_x + green_y > 100000L)
+   {
+      png_warning(png_ptr, "Invalid fixed cHRM green point specified");
+      return;
+   }
+   png_save_uint_32(buf + 16, (png_uint_32)green_x);
+   png_save_uint_32(buf + 20, (png_uint_32)green_y);
+
+   if (blue_x + blue_y > 100000L)
+   {
+      png_warning(png_ptr, "Invalid fixed cHRM blue point specified");
+      return;
+   }
+   png_save_uint_32(buf + 24, (png_uint_32)blue_x);
+   png_save_uint_32(buf + 28, (png_uint_32)blue_y);
+
+   png_write_chunk(png_ptr, (png_bytep)png_cHRM, buf, (png_size_t)32);
+}
+#endif
+#endif
+
+#if defined(PNG_WRITE_tRNS_SUPPORTED)
+/* write the tRNS chunk */
+void /* PRIVATE */
+png_write_tRNS(png_structp png_ptr, png_bytep trans, png_color_16p tran,
+   int num_trans, int color_type)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_tRNS;
+#endif
+   png_byte buf[6];
+
+   png_debug(1, "in png_write_tRNS\n");
+   if (color_type == PNG_COLOR_TYPE_PALETTE)
+   {
+      if (num_trans <= 0 || num_trans > (int)png_ptr->num_palette)
+      {
+         png_warning(png_ptr,"Invalid number of transparent colors specified");
+         return;
+      }
+      /* write the chunk out as it is */
+      png_write_chunk(png_ptr, (png_bytep)png_tRNS, trans, (png_size_t)num_trans);
+   }
+   else if (color_type == PNG_COLOR_TYPE_GRAY)
+   {
+      /* one 16 bit value */
+      if(tran->gray >= (1 << png_ptr->bit_depth))
+      {
+         png_warning(png_ptr,
+           "Ignoring attempt to write tRNS chunk out-of-range for bit_depth");
+         return;
+      }
+      png_save_uint_16(buf, tran->gray);
+      png_write_chunk(png_ptr, (png_bytep)png_tRNS, buf, (png_size_t)2);
+   }
+   else if (color_type == PNG_COLOR_TYPE_RGB)
+   {
+      /* three 16 bit values */
+      png_save_uint_16(buf, tran->red);
+      png_save_uint_16(buf + 2, tran->green);
+      png_save_uint_16(buf + 4, tran->blue);
+      if(png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))
+         {
+            png_warning(png_ptr,
+              "Ignoring attempt to write 16-bit tRNS chunk when bit_depth is 8");
+            return;
+         }
+      png_write_chunk(png_ptr, (png_bytep)png_tRNS, buf, (png_size_t)6);
+   }
+   else
+   {
+      png_warning(png_ptr, "Can't write tRNS with an alpha channel");
+   }
+}
+#endif
+
+#if defined(PNG_WRITE_bKGD_SUPPORTED)
+/* write the background chunk */
+void /* PRIVATE */
+png_write_bKGD(png_structp png_ptr, png_color_16p back, int color_type)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_bKGD;
+#endif
+   png_byte buf[6];
+
+   png_debug(1, "in png_write_bKGD\n");
+   if (color_type == PNG_COLOR_TYPE_PALETTE)
+   {
+      if (
+#if defined(PNG_MNG_FEATURES_SUPPORTED)
+          (png_ptr->num_palette ||
+          (!(png_ptr->mng_features_permitted & PNG_FLAG_MNG_EMPTY_PLTE))) &&
+#endif
+         back->index > png_ptr->num_palette)
+      {
+         png_warning(png_ptr, "Invalid background palette index");
+         return;
+      }
+      buf[0] = back->index;
+      png_write_chunk(png_ptr, (png_bytep)png_bKGD, buf, (png_size_t)1);
+   }
+   else if (color_type & PNG_COLOR_MASK_COLOR)
+   {
+      png_save_uint_16(buf, back->red);
+      png_save_uint_16(buf + 2, back->green);
+      png_save_uint_16(buf + 4, back->blue);
+      if(png_ptr->bit_depth == 8 && (buf[0] | buf[2] | buf[4]))
+         {
+            png_warning(png_ptr,
+              "Ignoring attempt to write 16-bit bKGD chunk when bit_depth is 8");
+            return;
+         }
+      png_write_chunk(png_ptr, (png_bytep)png_bKGD, buf, (png_size_t)6);
+   }
+   else
+   {
+      if(back->gray >= (1 << png_ptr->bit_depth))
+      {
+         png_warning(png_ptr,
+           "Ignoring attempt to write bKGD chunk out-of-range for bit_depth");
+         return;
+      }
+      png_save_uint_16(buf, back->gray);
+      png_write_chunk(png_ptr, (png_bytep)png_bKGD, buf, (png_size_t)2);
+   }
+}
+#endif
+
+#if defined(PNG_WRITE_hIST_SUPPORTED)
+/* write the histogram */
+void /* PRIVATE */
+png_write_hIST(png_structp png_ptr, png_uint_16p hist, int num_hist)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_hIST;
+#endif
+   int i;
+   png_byte buf[3];
+
+   png_debug(1, "in png_write_hIST\n");
+   if (num_hist > (int)png_ptr->num_palette)
+   {
+      png_debug2(3, "num_hist = %d, num_palette = %d\n", num_hist,
+         png_ptr->num_palette);
+      png_warning(png_ptr, "Invalid number of histogram entries specified");
+      return;
+   }
+
+   png_write_chunk_start(png_ptr, png_hIST, (png_uint_32)(num_hist * 2));
+   for (i = 0; i < num_hist; i++)
+   {
+      png_save_uint_16(buf, hist[i]);
+      png_write_chunk_data(png_ptr, buf, (png_size_t)2);
+   }
+   png_write_chunk_end(png_ptr);
+}
+#endif
+
+#if defined(PNG_WRITE_TEXT_SUPPORTED) || defined(PNG_WRITE_pCAL_SUPPORTED) || \
+    defined(PNG_WRITE_iCCP_SUPPORTED) || defined(PNG_WRITE_sPLT_SUPPORTED)
+/* Check that the tEXt or zTXt keyword is valid per PNG 1.0 specification,
+ * and if invalid, correct the keyword rather than discarding the entire
+ * chunk.  The PNG 1.0 specification requires keywords 1-79 characters in
+ * length, forbids leading or trailing whitespace, multiple internal spaces,
+ * and the non-break space (0x80) from ISO 8859-1.  Returns keyword length.
+ *
+ * The new_key is allocated to hold the corrected keyword and must be freed
+ * by the calling routine.  This avoids problems with trying to write to
+ * static keywords without having to have duplicate copies of the strings.
+ */
+png_size_t /* PRIVATE */
+png_check_keyword(png_structp png_ptr, png_charp key, png_charpp new_key)
+{
+   png_size_t key_len;
+   png_charp kp, dp;
+   int kflag;
+   int kwarn=0;
+
+   png_debug(1, "in png_check_keyword\n");
+   *new_key = NULL;
+
+   if (key == NULL || (key_len = png_strlen(key)) == 0)
+   {
+      png_warning(png_ptr, "zero length keyword");
+      return ((png_size_t)0);
+   }
+
+   png_debug1(2, "Keyword to be checked is '%s'\n", key);
+
+   *new_key = (png_charp)png_malloc_warn(png_ptr, (png_uint_32)(key_len + 2));
+   if (*new_key == NULL)
+   {
+      png_warning(png_ptr, "Out of memory while procesing keyword");
+      return ((png_size_t)0);
+   }
+
+   /* Replace non-printing characters with a blank and print a warning */
+   for (kp = key, dp = *new_key; *kp != '\0'; kp++, dp++)
+   {
+      if ((png_byte)*kp < 0x20 ||
+         ((png_byte)*kp > 0x7E && (png_byte)*kp < 0xA1))
+      {
+#if !defined(PNG_NO_STDIO) && !defined(_WIN32_WCE)
+         char msg[40];
+
+         png_snprintf(msg, 40,
+           "invalid keyword character 0x%02X", (png_byte)*kp);
+         png_warning(png_ptr, msg);
+#else
+         png_warning(png_ptr, "invalid character in keyword");
+#endif
+         *dp = ' ';
+      }
+      else
+      {
+         *dp = *kp;
+      }
+   }
+   *dp = '\0';
+
+   /* Remove any trailing white space. */
+   kp = *new_key + key_len - 1;
+   if (*kp == ' ')
+   {
+      png_warning(png_ptr, "trailing spaces removed from keyword");
+
+      while (*kp == ' ')
+      {
+        *(kp--) = '\0';
+        key_len--;
+      }
+   }
+
+   /* Remove any leading white space. */
+   kp = *new_key;
+   if (*kp == ' ')
+   {
+      png_warning(png_ptr, "leading spaces removed from keyword");
+
+      while (*kp == ' ')
+      {
+        kp++;
+        key_len--;
+      }
+   }
+
+   png_debug1(2, "Checking for multiple internal spaces in '%s'\n", kp);
+
+   /* Remove multiple internal spaces. */
+   for (kflag = 0, dp = *new_key; *kp != '\0'; kp++)
+   {
+      if (*kp == ' ' && kflag == 0)
+      {
+         *(dp++) = *kp;
+         kflag = 1;
+      }
+      else if (*kp == ' ')
+      {
+         key_len--;
+         kwarn=1;
+      }
+      else
+      {
+         *(dp++) = *kp;
+         kflag = 0;
+      }
+   }
+   *dp = '\0';
+   if(kwarn)
+      png_warning(png_ptr, "extra interior spaces removed from keyword");
+
+   if (key_len == 0)
+   {
+      png_free(png_ptr, *new_key);
+      *new_key=NULL;
+      png_warning(png_ptr, "Zero length keyword");
+   }
+
+   if (key_len > 79)
+   {
+      png_warning(png_ptr, "keyword length must be 1 - 79 characters");
+      new_key[79] = '\0';
+      key_len = 79;
+   }
+
+   return (key_len);
+}
+#endif
+
+#if defined(PNG_WRITE_tEXt_SUPPORTED)
+/* write a tEXt chunk */
+void /* PRIVATE */
+png_write_tEXt(png_structp png_ptr, png_charp key, png_charp text,
+   png_size_t text_len)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_tEXt;
+#endif
+   png_size_t key_len;
+   png_charp new_key;
+
+   png_debug(1, "in png_write_tEXt\n");
+   if (key == NULL || (key_len = png_check_keyword(png_ptr, key, &new_key))==0)
+   {
+      png_warning(png_ptr, "Empty keyword in tEXt chunk");
+      return;
+   }
+
+   if (text == NULL || *text == '\0')
+      text_len = 0;
+   else
+      text_len = png_strlen(text);
+
+   /* make sure we include the 0 after the key */
+   png_write_chunk_start(png_ptr, (png_bytep)png_tEXt, (png_uint_32)key_len+text_len+1);
+   /*
+    * We leave it to the application to meet PNG-1.0 requirements on the
+    * contents of the text.  PNG-1.0 through PNG-1.2 discourage the use of
+    * any non-Latin-1 characters except for NEWLINE.  ISO PNG will forbid them.
+    * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
+    */
+   png_write_chunk_data(png_ptr, (png_bytep)new_key, key_len + 1);
+   if (text_len)
+      png_write_chunk_data(png_ptr, (png_bytep)text, text_len);
+
+   png_write_chunk_end(png_ptr);
+   png_free(png_ptr, new_key);
+}
+#endif
+
+#if defined(PNG_WRITE_zTXt_SUPPORTED)
+/* write a compressed text chunk */
+void /* PRIVATE */
+png_write_zTXt(png_structp png_ptr, png_charp key, png_charp text,
+   png_size_t text_len, int compression)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_zTXt;
+#endif
+   png_size_t key_len;
+   char buf[1];
+   png_charp new_key;
+   compression_state comp;
+
+   png_debug(1, "in png_write_zTXt\n");
+
+   comp.num_output_ptr = 0;
+   comp.max_output_ptr = 0;
+   comp.output_ptr = NULL;
+   comp.input = NULL;
+   comp.input_len = 0;
+
+   if (key == NULL || (key_len = png_check_keyword(png_ptr, key, &new_key))==0)
+   {
+      png_warning(png_ptr, "Empty keyword in zTXt chunk");
+      return;
+   }
+
+   if (text == NULL || *text == '\0' || compression==PNG_TEXT_COMPRESSION_NONE)
+   {
+      png_write_tEXt(png_ptr, new_key, text, (png_size_t)0);
+      png_free(png_ptr, new_key);
+      return;
+   }
+
+   text_len = png_strlen(text);
+
+   /* compute the compressed data; do it now for the length */
+   text_len = png_text_compress(png_ptr, text, text_len, compression,
+       &comp);
+
+   /* write start of chunk */
+   png_write_chunk_start(png_ptr, (png_bytep)png_zTXt, (png_uint_32)
+      (key_len+text_len+2));
+   /* write key */
+   png_write_chunk_data(png_ptr, (png_bytep)new_key, key_len + 1);
+   png_free(png_ptr, new_key);
+
+   buf[0] = (png_byte)compression;
+   /* write compression */
+   png_write_chunk_data(png_ptr, (png_bytep)buf, (png_size_t)1);
+   /* write the compressed data */
+   png_write_compressed_data_out(png_ptr, &comp);
+
+   /* close the chunk */
+   png_write_chunk_end(png_ptr);
+}
+#endif
+
+#if defined(PNG_WRITE_iTXt_SUPPORTED)
+/* write an iTXt chunk */
+void /* PRIVATE */
+png_write_iTXt(png_structp png_ptr, int compression, png_charp key,
+    png_charp lang, png_charp lang_key, png_charp text)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_iTXt;
+#endif
+   png_size_t lang_len, key_len, lang_key_len, text_len;
+   png_charp new_lang, new_key;
+   png_byte cbuf[2];
+   compression_state comp;
+
+   png_debug(1, "in png_write_iTXt\n");
+
+   comp.num_output_ptr = 0;
+   comp.max_output_ptr = 0;
+   comp.output_ptr = NULL;
+   comp.input = NULL;
+
+   if (key == NULL || (key_len = png_check_keyword(png_ptr, key, &new_key))==0)
+   {
+      png_warning(png_ptr, "Empty keyword in iTXt chunk");
+      return;
+   }
+   if (lang == NULL || (lang_len = png_check_keyword(png_ptr, lang, &new_lang))==0)
+   {
+      png_warning(png_ptr, "Empty language field in iTXt chunk");
+      new_lang = NULL;
+      lang_len = 0;
+   }
+
+   if (lang_key == NULL)
+     lang_key_len = 0;
+   else
+     lang_key_len = png_strlen(lang_key);
+
+   if (text == NULL)
+      text_len = 0;
+   else
+     text_len = png_strlen(text);
+
+   /* compute the compressed data; do it now for the length */
+   text_len = png_text_compress(png_ptr, text, text_len, compression-2,
+      &comp);
+
+
+   /* make sure we include the compression flag, the compression byte,
+    * and the NULs after the key, lang, and lang_key parts */
+
+   png_write_chunk_start(png_ptr, (png_bytep)png_iTXt,
+          (png_uint_32)(
+        5 /* comp byte, comp flag, terminators for key, lang and lang_key */
+        + key_len
+        + lang_len
+        + lang_key_len
+        + text_len));
+
+   /*
+    * We leave it to the application to meet PNG-1.0 requirements on the
+    * contents of the text.  PNG-1.0 through PNG-1.2 discourage the use of
+    * any non-Latin-1 characters except for NEWLINE.  ISO PNG will forbid them.
+    * The NUL character is forbidden by PNG-1.0 through PNG-1.2 and ISO PNG.
+    */
+   png_write_chunk_data(png_ptr, (png_bytep)new_key, key_len + 1);
+
+   /* set the compression flag */
+   if (compression == PNG_ITXT_COMPRESSION_NONE || \
+       compression == PNG_TEXT_COMPRESSION_NONE)
+       cbuf[0] = 0;
+   else /* compression == PNG_ITXT_COMPRESSION_zTXt */
+       cbuf[0] = 1;
+   /* set the compression method */
+   cbuf[1] = 0;
+   png_write_chunk_data(png_ptr, cbuf, 2);
+
+   cbuf[0] = 0;
+   png_write_chunk_data(png_ptr, (new_lang ? (png_bytep)new_lang : cbuf), lang_len + 1);
+   png_write_chunk_data(png_ptr, (lang_key ? (png_bytep)lang_key : cbuf), lang_key_len + 1);
+   png_write_compressed_data_out(png_ptr, &comp);
+
+   png_write_chunk_end(png_ptr);
+   png_free(png_ptr, new_key);
+   if (new_lang)
+     png_free(png_ptr, new_lang);
+}
+#endif
+
+#if defined(PNG_WRITE_oFFs_SUPPORTED)
+/* write the oFFs chunk */
+void /* PRIVATE */
+png_write_oFFs(png_structp png_ptr, png_int_32 x_offset, png_int_32 y_offset,
+   int unit_type)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_oFFs;
+#endif
+   png_byte buf[9];
+
+   png_debug(1, "in png_write_oFFs\n");
+   if (unit_type >= PNG_OFFSET_LAST)
+      png_warning(png_ptr, "Unrecognized unit type for oFFs chunk");
+
+   png_save_int_32(buf, x_offset);
+   png_save_int_32(buf + 4, y_offset);
+   buf[8] = (png_byte)unit_type;
+
+   png_write_chunk(png_ptr, png_oFFs, buf, (png_size_t)9);
+}
+#endif
+#if defined(PNG_WRITE_pCAL_SUPPORTED)
+/* write the pCAL chunk (described in the PNG extensions document) */
+void /* PRIVATE */
+png_write_pCAL(png_structp png_ptr, png_charp purpose, png_int_32 X0,
+   png_int_32 X1, int type, int nparams, png_charp units, png_charpp params)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_pCAL;
+#endif
+   png_size_t purpose_len, units_len, total_len;
+   png_uint_32p params_len;
+   png_byte buf[10];
+   png_charp new_purpose;
+   int i;
+
+   png_debug1(1, "in png_write_pCAL (%d parameters)\n", nparams);
+   if (type >= PNG_EQUATION_LAST)
+      png_warning(png_ptr, "Unrecognized equation type for pCAL chunk");
+
+   purpose_len = png_check_keyword(png_ptr, purpose, &new_purpose) + 1;
+   png_debug1(3, "pCAL purpose length = %d\n", (int)purpose_len);
+   units_len = png_strlen(units) + (nparams == 0 ? 0 : 1);
+   png_debug1(3, "pCAL units length = %d\n", (int)units_len);
+   total_len = purpose_len + units_len + 10;
+
+   params_len = (png_uint_32p)png_malloc(png_ptr, (png_uint_32)(nparams
+      *png_sizeof(png_uint_32)));
+
+   /* Find the length of each parameter, making sure we don't count the
+      null terminator for the last parameter. */
+   for (i = 0; i < nparams; i++)
+   {
+      params_len[i] = png_strlen(params[i]) + (i == nparams - 1 ? 0 : 1);
+      png_debug2(3, "pCAL parameter %d length = %lu\n", i, params_len[i]);
+      total_len += (png_size_t)params_len[i];
+   }
+
+   png_debug1(3, "pCAL total length = %d\n", (int)total_len);
+   png_write_chunk_start(png_ptr, png_pCAL, (png_uint_32)total_len);
+   png_write_chunk_data(png_ptr, (png_bytep)new_purpose, purpose_len);
+   png_save_int_32(buf, X0);
+   png_save_int_32(buf + 4, X1);
+   buf[8] = (png_byte)type;
+   buf[9] = (png_byte)nparams;
+   png_write_chunk_data(png_ptr, buf, (png_size_t)10);
+   png_write_chunk_data(png_ptr, (png_bytep)units, (png_size_t)units_len);
+
+   png_free(png_ptr, new_purpose);
+
+   for (i = 0; i < nparams; i++)
+   {
+      png_write_chunk_data(png_ptr, (png_bytep)params[i],
+         (png_size_t)params_len[i]);
+   }
+
+   png_free(png_ptr, params_len);
+   png_write_chunk_end(png_ptr);
+}
+#endif
+
+#if defined(PNG_WRITE_sCAL_SUPPORTED)
+/* write the sCAL chunk */
+#if defined(PNG_FLOATING_POINT_SUPPORTED) && !defined(PNG_NO_STDIO)
+void /* PRIVATE */
+png_write_sCAL(png_structp png_ptr, int unit, double width, double height)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_sCAL;
+#endif
+   char buf[64];
+   png_size_t total_len;
+
+   png_debug(1, "in png_write_sCAL\n");
+
+   buf[0] = (char)unit;
+#if defined(_WIN32_WCE)
+/* sprintf() function is not supported on WindowsCE */
+   {
+      wchar_t wc_buf[32];
+      size_t wc_len;
+      swprintf(wc_buf, TEXT("%12.12e"), width);
+      wc_len = wcslen(wc_buf);
+      WideCharToMultiByte(CP_ACP, 0, wc_buf, -1, buf + 1, wc_len, NULL, NULL);
+      total_len = wc_len + 2;
+      swprintf(wc_buf, TEXT("%12.12e"), height);
+      wc_len = wcslen(wc_buf);
+      WideCharToMultiByte(CP_ACP, 0, wc_buf, -1, buf + total_len, wc_len,
+         NULL, NULL);
+      total_len += wc_len;
+   }
+#else
+   png_snprintf(buf + 1, 63, "%12.12e", width);
+   total_len = 1 + png_strlen(buf + 1) + 1;
+   png_snprintf(buf + total_len, 64-total_len, "%12.12e", height);
+   total_len += png_strlen(buf + total_len);
+#endif
+
+   png_debug1(3, "sCAL total length = %u\n", (unsigned int)total_len);
+   png_write_chunk(png_ptr, png_sCAL, (png_bytep)buf, total_len);
+}
+#else
+#ifdef PNG_FIXED_POINT_SUPPORTED
+void /* PRIVATE */
+png_write_sCAL_s(png_structp png_ptr, int unit, png_charp width,
+   png_charp height)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_sCAL;
+#endif
+   png_byte buf[64];
+   png_size_t wlen, hlen, total_len;
+
+   png_debug(1, "in png_write_sCAL_s\n");
+
+   wlen = png_strlen(width);
+   hlen = png_strlen(height);
+   total_len = wlen + hlen + 2;
+   if (total_len > 64)
+   {
+      png_warning(png_ptr, "Can't write sCAL (buffer too small)");
+      return;
+   }
+
+   buf[0] = (png_byte)unit;
+   png_memcpy(buf + 1, width, wlen + 1);      /* append the '\0' here */
+   png_memcpy(buf + wlen + 2, height, hlen);  /* do NOT append the '\0' here */
+
+   png_debug1(3, "sCAL total length = %u\n", (unsigned int)total_len);
+   png_write_chunk(png_ptr, png_sCAL, buf, total_len);
+}
+#endif
+#endif
+#endif
+
+#if defined(PNG_WRITE_pHYs_SUPPORTED)
+/* write the pHYs chunk */
+void /* PRIVATE */
+png_write_pHYs(png_structp png_ptr, png_uint_32 x_pixels_per_unit,
+   png_uint_32 y_pixels_per_unit,
+   int unit_type)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_pHYs;
+#endif
+   png_byte buf[9];
+
+   png_debug(1, "in png_write_pHYs\n");
+   if (unit_type >= PNG_RESOLUTION_LAST)
+      png_warning(png_ptr, "Unrecognized unit type for pHYs chunk");
+
+   png_save_uint_32(buf, x_pixels_per_unit);
+   png_save_uint_32(buf + 4, y_pixels_per_unit);
+   buf[8] = (png_byte)unit_type;
+
+   png_write_chunk(png_ptr, png_pHYs, buf, (png_size_t)9);
+}
+#endif
+
+#if defined(PNG_WRITE_tIME_SUPPORTED)
+/* Write the tIME chunk.  Use either png_convert_from_struct_tm()
+ * or png_convert_from_time_t(), or fill in the structure yourself.
+ */
+void /* PRIVATE */
+png_write_tIME(png_structp png_ptr, png_timep mod_time)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   PNG_tIME;
+#endif
+   png_byte buf[7];
+
+   png_debug(1, "in png_write_tIME\n");
+   if (mod_time->month  > 12 || mod_time->month  < 1 ||
+       mod_time->day    > 31 || mod_time->day    < 1 ||
+       mod_time->hour   > 23 || mod_time->second > 60)
+   {
+      png_warning(png_ptr, "Invalid time specified for tIME chunk");
+      return;
+   }
+
+   png_save_uint_16(buf, mod_time->year);
+   buf[2] = mod_time->month;
+   buf[3] = mod_time->day;
+   buf[4] = mod_time->hour;
+   buf[5] = mod_time->minute;
+   buf[6] = mod_time->second;
+
+   png_write_chunk(png_ptr, png_tIME, buf, (png_size_t)7);
+}
+#endif
+
+/* initializes the row writing capability of libpng */
+void /* PRIVATE */
+png_write_start_row(png_structp png_ptr)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+   /* start of interlace block */
+   int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+
+   /* offset to next interlace block */
+   int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+
+   /* start of interlace block in the y direction */
+   int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
+
+   /* offset to next interlace block in the y direction */
+   int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+#endif
+
+   png_size_t buf_size;
+
+   png_debug(1, "in png_write_start_row\n");
+   buf_size = (png_size_t)(PNG_ROWBYTES(
+      png_ptr->usr_channels*png_ptr->usr_bit_depth,png_ptr->width)+1);
+
+   /* set up row buffer */
+   png_ptr->row_buf = (png_bytep)png_malloc(png_ptr, (png_uint_32)buf_size);
+   png_ptr->row_buf[0] = PNG_FILTER_VALUE_NONE;
+
+#ifndef PNG_NO_WRITE_FILTERING
+   /* set up filtering buffer, if using this filter */
+   if (png_ptr->do_filter & PNG_FILTER_SUB)
+   {
+      png_ptr->sub_row = (png_bytep)png_malloc(png_ptr,
+         (png_ptr->rowbytes + 1));
+      png_ptr->sub_row[0] = PNG_FILTER_VALUE_SUB;
+   }
+
+   /* We only need to keep the previous row if we are using one of these. */
+   if (png_ptr->do_filter & (PNG_FILTER_AVG | PNG_FILTER_UP | PNG_FILTER_PAETH))
+   {
+     /* set up previous row buffer */
+      png_ptr->prev_row = (png_bytep)png_malloc(png_ptr, (png_uint_32)buf_size);
+      png_memset(png_ptr->prev_row, 0, buf_size);
+
+      if (png_ptr->do_filter & PNG_FILTER_UP)
+      {
+         png_ptr->up_row = (png_bytep)png_malloc(png_ptr,
+            (png_ptr->rowbytes + 1));
+         png_ptr->up_row[0] = PNG_FILTER_VALUE_UP;
+      }
+
+      if (png_ptr->do_filter & PNG_FILTER_AVG)
+      {
+         png_ptr->avg_row = (png_bytep)png_malloc(png_ptr,
+            (png_ptr->rowbytes + 1));
+         png_ptr->avg_row[0] = PNG_FILTER_VALUE_AVG;
+      }
+
+      if (png_ptr->do_filter & PNG_FILTER_PAETH)
+      {
+         png_ptr->paeth_row = (png_bytep)png_malloc(png_ptr,
+            (png_ptr->rowbytes + 1));
+         png_ptr->paeth_row[0] = PNG_FILTER_VALUE_PAETH;
+      }
+#endif /* PNG_NO_WRITE_FILTERING */
+   }
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+   /* if interlaced, we need to set up width and height of pass */
+   if (png_ptr->interlaced)
+   {
+      if (!(png_ptr->transformations & PNG_INTERLACE))
+      {
+         png_ptr->num_rows = (png_ptr->height + png_pass_yinc[0] - 1 -
+            png_pass_ystart[0]) / png_pass_yinc[0];
+         png_ptr->usr_width = (png_ptr->width + png_pass_inc[0] - 1 -
+            png_pass_start[0]) / png_pass_inc[0];
+      }
+      else
+      {
+         png_ptr->num_rows = png_ptr->height;
+         png_ptr->usr_width = png_ptr->width;
+      }
+   }
+   else
+#endif
+   {
+      png_ptr->num_rows = png_ptr->height;
+      png_ptr->usr_width = png_ptr->width;
+   }
+   png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+   png_ptr->zstream.next_out = png_ptr->zbuf;
+}
+
+/* Internal use only.  Called when finished processing a row of data. */
+void /* PRIVATE */
+png_write_finish_row(png_structp png_ptr)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+   /* start of interlace block */
+   int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+
+   /* offset to next interlace block */
+   int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+
+   /* start of interlace block in the y direction */
+   int png_pass_ystart[7] = {0, 0, 4, 0, 2, 0, 1};
+
+   /* offset to next interlace block in the y direction */
+   int png_pass_yinc[7] = {8, 8, 8, 4, 4, 2, 2};
+#endif
+
+   int ret;
+
+   png_debug(1, "in png_write_finish_row\n");
+   /* next row */
+   png_ptr->row_number++;
+
+   /* see if we are done */
+   if (png_ptr->row_number < png_ptr->num_rows)
+      return;
+
+#ifdef PNG_WRITE_INTERLACING_SUPPORTED
+   /* if interlaced, go to next pass */
+   if (png_ptr->interlaced)
+   {
+      png_ptr->row_number = 0;
+      if (png_ptr->transformations & PNG_INTERLACE)
+      {
+         png_ptr->pass++;
+      }
+      else
+      {
+         /* loop until we find a non-zero width or height pass */
+         do
+         {
+            png_ptr->pass++;
+            if (png_ptr->pass >= 7)
+               break;
+            png_ptr->usr_width = (png_ptr->width +
+               png_pass_inc[png_ptr->pass] - 1 -
+               png_pass_start[png_ptr->pass]) /
+               png_pass_inc[png_ptr->pass];
+            png_ptr->num_rows = (png_ptr->height +
+               png_pass_yinc[png_ptr->pass] - 1 -
+               png_pass_ystart[png_ptr->pass]) /
+               png_pass_yinc[png_ptr->pass];
+            if (png_ptr->transformations & PNG_INTERLACE)
+               break;
+         } while (png_ptr->usr_width == 0 || png_ptr->num_rows == 0);
+
+      }
+
+      /* reset the row above the image for the next pass */
+      if (png_ptr->pass < 7)
+      {
+         if (png_ptr->prev_row != NULL)
+            png_memset(png_ptr->prev_row, 0,
+               (png_size_t)(PNG_ROWBYTES(png_ptr->usr_channels*
+               png_ptr->usr_bit_depth,png_ptr->width))+1);
+         return;
+      }
+   }
+#endif
+
+   /* if we get here, we've just written the last row, so we need
+      to flush the compressor */
+   do
+   {
+      /* tell the compressor we are done */
+      ret = deflate(&png_ptr->zstream, Z_FINISH);
+      /* check for an error */
+      if (ret == Z_OK)
+      {
+         /* check to see if we need more room */
+         if (!(png_ptr->zstream.avail_out))
+         {
+            png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
+            png_ptr->zstream.next_out = png_ptr->zbuf;
+            png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+         }
+      }
+      else if (ret != Z_STREAM_END)
+      {
+         if (png_ptr->zstream.msg != NULL)
+            png_error(png_ptr, png_ptr->zstream.msg);
+         else
+            png_error(png_ptr, "zlib error");
+      }
+   } while (ret != Z_STREAM_END);
+
+   /* write any extra space */
+   if (png_ptr->zstream.avail_out < png_ptr->zbuf_size)
+   {
+      png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size -
+         png_ptr->zstream.avail_out);
+   }
+
+   deflateReset(&png_ptr->zstream);
+   png_ptr->zstream.data_type = Z_BINARY;
+}
+
+#if defined(PNG_WRITE_INTERLACING_SUPPORTED)
+/* Pick out the correct pixels for the interlace pass.
+ * The basic idea here is to go through the row with a source
+ * pointer and a destination pointer (sp and dp), and copy the
+ * correct pixels for the pass.  As the row gets compacted,
+ * sp will always be >= dp, so we should never overwrite anything.
+ * See the default: case for the easiest code to understand.
+ */
+void /* PRIVATE */
+png_do_write_interlace(png_row_infop row_info, png_bytep row, int pass)
+{
+#ifdef PNG_USE_LOCAL_ARRAYS
+   /* arrays to facilitate easy interlacing - use pass (0 - 6) as index */
+
+   /* start of interlace block */
+   int png_pass_start[7] = {0, 4, 0, 2, 0, 1, 0};
+
+   /* offset to next interlace block */
+   int png_pass_inc[7] = {8, 8, 4, 4, 2, 2, 1};
+#endif
+
+   png_debug(1, "in png_do_write_interlace\n");
+   /* we don't have to do anything on the last pass (6) */
+#if defined(PNG_USELESS_TESTS_SUPPORTED)
+   if (row != NULL && row_info != NULL && pass < 6)
+#else
+   if (pass < 6)
+#endif
+   {
+      /* each pixel depth is handled separately */
+      switch (row_info->pixel_depth)
+      {
+         case 1:
+         {
+            png_bytep sp;
+            png_bytep dp;
+            int shift;
+            int d;
+            int value;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            dp = row;
+            d = 0;
+            shift = 7;
+            for (i = png_pass_start[pass]; i < row_width;
+               i += png_pass_inc[pass])
+            {
+               sp = row + (png_size_t)(i >> 3);
+               value = (int)(*sp >> (7 - (int)(i & 0x07))) & 0x01;
+               d |= (value << shift);
+
+               if (shift == 0)
+               {
+                  shift = 7;
+                  *dp++ = (png_byte)d;
+                  d = 0;
+               }
+               else
+                  shift--;
+
+            }
+            if (shift != 7)
+               *dp = (png_byte)d;
+            break;
+         }
+         case 2:
+         {
+            png_bytep sp;
+            png_bytep dp;
+            int shift;
+            int d;
+            int value;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            dp = row;
+            shift = 6;
+            d = 0;
+            for (i = png_pass_start[pass]; i < row_width;
+               i += png_pass_inc[pass])
+            {
+               sp = row + (png_size_t)(i >> 2);
+               value = (*sp >> ((3 - (int)(i & 0x03)) << 1)) & 0x03;
+               d |= (value << shift);
+
+               if (shift == 0)
+               {
+                  shift = 6;
+                  *dp++ = (png_byte)d;
+                  d = 0;
+               }
+               else
+                  shift -= 2;
+            }
+            if (shift != 6)
+                   *dp = (png_byte)d;
+            break;
+         }
+         case 4:
+         {
+            png_bytep sp;
+            png_bytep dp;
+            int shift;
+            int d;
+            int value;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+
+            dp = row;
+            shift = 4;
+            d = 0;
+            for (i = png_pass_start[pass]; i < row_width;
+               i += png_pass_inc[pass])
+            {
+               sp = row + (png_size_t)(i >> 1);
+               value = (*sp >> ((1 - (int)(i & 0x01)) << 2)) & 0x0f;
+               d |= (value << shift);
+
+               if (shift == 0)
+               {
+                  shift = 4;
+                  *dp++ = (png_byte)d;
+                  d = 0;
+               }
+               else
+                  shift -= 4;
+            }
+            if (shift != 4)
+               *dp = (png_byte)d;
+            break;
+         }
+         default:
+         {
+            png_bytep sp;
+            png_bytep dp;
+            png_uint_32 i;
+            png_uint_32 row_width = row_info->width;
+            png_size_t pixel_bytes;
+
+            /* start at the beginning */
+            dp = row;
+            /* find out how many bytes each pixel takes up */
+            pixel_bytes = (row_info->pixel_depth >> 3);
+            /* loop through the row, only looking at the pixels that
+               matter */
+            for (i = png_pass_start[pass]; i < row_width;
+               i += png_pass_inc[pass])
+            {
+               /* find out where the original pixel is */
+               sp = row + (png_size_t)i * pixel_bytes;
+               /* move the pixel */
+               if (dp != sp)
+                  png_memcpy(dp, sp, pixel_bytes);
+               /* next pixel */
+               dp += pixel_bytes;
+            }
+            break;
+         }
+      }
+      /* set new row width */
+      row_info->width = (row_info->width +
+         png_pass_inc[pass] - 1 -
+         png_pass_start[pass]) /
+         png_pass_inc[pass];
+         row_info->rowbytes = PNG_ROWBYTES(row_info->pixel_depth,
+            row_info->width);
+   }
+}
+#endif
+
+/* This filters the row, chooses which filter to use, if it has not already
+ * been specified by the application, and then writes the row out with the
+ * chosen filter.
+ */
+#define PNG_MAXSUM (((png_uint_32)(-1)) >> 1)
+#define PNG_HISHIFT 10
+#define PNG_LOMASK ((png_uint_32)0xffffL)
+#define PNG_HIMASK ((png_uint_32)(~PNG_LOMASK >> PNG_HISHIFT))
+void /* PRIVATE */
+png_write_find_filter(png_structp png_ptr, png_row_infop row_info)
+{
+   png_bytep prev_row, best_row, row_buf;
+   png_uint_32 mins, bpp;
+   png_byte filter_to_do = png_ptr->do_filter;
+   png_uint_32 row_bytes = row_info->rowbytes;
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+   int num_p_filters = (int)png_ptr->num_prev_filters;
+#endif
+
+   png_debug(1, "in png_write_find_filter\n");
+   /* find out how many bytes offset each pixel is */
+   bpp = (row_info->pixel_depth + 7) >> 3;
+
+   prev_row = png_ptr->prev_row;
+   best_row = row_buf = png_ptr->row_buf;
+#ifndef PNG_NO_WRITE_FILTER
+   mins = PNG_MAXSUM;
+
+   /* The prediction method we use is to find which method provides the
+    * smallest value when summing the absolute values of the distances
+    * from zero, using anything >= 128 as negative numbers.  This is known
+    * as the "minimum sum of absolute differences" heuristic.  Other
+    * heuristics are the "weighted minimum sum of absolute differences"
+    * (experimental and can in theory improve compression), and the "zlib
+    * predictive" method (not implemented yet), which does test compressions
+    * of lines using different filter methods, and then chooses the
+    * (series of) filter(s) that give minimum compressed data size (VERY
+    * computationally expensive).
+    *
+    * GRR 980525:  consider also
+    *   (1) minimum sum of absolute differences from running average (i.e.,
+    *       keep running sum of non-absolute differences & count of bytes)
+    *       [track dispersion, too?  restart average if dispersion too large?]
+    *  (1b) minimum sum of absolute differences from sliding average, probably
+    *       with window size <= deflate window (usually 32K)
+    *   (2) minimum sum of squared differences from zero or running average
+    *       (i.e., ~ root-mean-square approach)
+    */
+
+
+   /* We don't need to test the 'no filter' case if this is the only filter
+    * that has been chosen, as it doesn't actually do anything to the data.
+    */
+   if ((filter_to_do & PNG_FILTER_NONE) &&
+       filter_to_do != PNG_FILTER_NONE)
+   {
+      png_bytep rp;
+      png_uint_32 sum = 0;
+      png_uint_32 i;
+      int v;
+
+      for (i = 0, rp = row_buf + 1; i < row_bytes; i++, rp++)
+      {
+         v = *rp;
+         sum += (v < 128) ? v : 256 - v;
+      }
+
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+      {
+         png_uint_32 sumhi, sumlo;
+         int j;
+         sumlo = sum & PNG_LOMASK;
+         sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK; /* Gives us some footroom */
+
+         /* Reduce the sum if we match any of the previous rows */
+         for (j = 0; j < num_p_filters; j++)
+         {
+            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
+            {
+               sumlo = (sumlo * png_ptr->filter_weights[j]) >>
+                  PNG_WEIGHT_SHIFT;
+               sumhi = (sumhi * png_ptr->filter_weights[j]) >>
+                  PNG_WEIGHT_SHIFT;
+            }
+         }
+
+         /* Factor in the cost of this filter (this is here for completeness,
+          * but it makes no sense to have a "cost" for the NONE filter, as
+          * it has the minimum possible computational cost - none).
+          */
+         sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>
+            PNG_COST_SHIFT;
+         sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_NONE]) >>
+            PNG_COST_SHIFT;
+
+         if (sumhi > PNG_HIMASK)
+            sum = PNG_MAXSUM;
+         else
+            sum = (sumhi << PNG_HISHIFT) + sumlo;
+      }
+#endif
+      mins = sum;
+   }
+
+   /* sub filter */
+   if (filter_to_do == PNG_FILTER_SUB)
+   /* it's the only filter so no testing is needed */
+   {
+      png_bytep rp, lp, dp;
+      png_uint_32 i;
+      for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
+           i++, rp++, dp++)
+      {
+         *dp = *rp;
+      }
+      for (lp = row_buf + 1; i < row_bytes;
+         i++, rp++, lp++, dp++)
+      {
+         *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
+      }
+      best_row = png_ptr->sub_row;
+   }
+
+   else if (filter_to_do & PNG_FILTER_SUB)
+   {
+      png_bytep rp, dp, lp;
+      png_uint_32 sum = 0, lmins = mins;
+      png_uint_32 i;
+      int v;
+
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+      /* We temporarily increase the "minimum sum" by the factor we
+       * would reduce the sum of this filter, so that we can do the
+       * early exit comparison without scaling the sum each time.
+       */
+      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+      {
+         int j;
+         png_uint_32 lmhi, lmlo;
+         lmlo = lmins & PNG_LOMASK;
+         lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
+
+         for (j = 0; j < num_p_filters; j++)
+         {
+            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
+            {
+               lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
+                  PNG_WEIGHT_SHIFT;
+               lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
+                  PNG_WEIGHT_SHIFT;
+            }
+         }
+
+         lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
+            PNG_COST_SHIFT;
+         lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
+            PNG_COST_SHIFT;
+
+         if (lmhi > PNG_HIMASK)
+            lmins = PNG_MAXSUM;
+         else
+            lmins = (lmhi << PNG_HISHIFT) + lmlo;
+      }
+#endif
+
+      for (i = 0, rp = row_buf + 1, dp = png_ptr->sub_row + 1; i < bpp;
+           i++, rp++, dp++)
+      {
+         v = *dp = *rp;
+
+         sum += (v < 128) ? v : 256 - v;
+      }
+      for (lp = row_buf + 1; i < row_bytes;
+         i++, rp++, lp++, dp++)
+      {
+         v = *dp = (png_byte)(((int)*rp - (int)*lp) & 0xff);
+
+         sum += (v < 128) ? v : 256 - v;
+
+         if (sum > lmins)  /* We are already worse, don't continue. */
+            break;
+      }
+
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+      {
+         int j;
+         png_uint_32 sumhi, sumlo;
+         sumlo = sum & PNG_LOMASK;
+         sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
+
+         for (j = 0; j < num_p_filters; j++)
+         {
+            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_SUB)
+            {
+               sumlo = (sumlo * png_ptr->inv_filter_weights[j]) >>
+                  PNG_WEIGHT_SHIFT;
+               sumhi = (sumhi * png_ptr->inv_filter_weights[j]) >>
+                  PNG_WEIGHT_SHIFT;
+            }
+         }
+
+         sumlo = (sumlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
+            PNG_COST_SHIFT;
+         sumhi = (sumhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_SUB]) >>
+            PNG_COST_SHIFT;
+
+         if (sumhi > PNG_HIMASK)
+            sum = PNG_MAXSUM;
+         else
+            sum = (sumhi << PNG_HISHIFT) + sumlo;
+      }
+#endif
+
+      if (sum < mins)
+      {
+         mins = sum;
+         best_row = png_ptr->sub_row;
+      }
+   }
+
+   /* up filter */
+   if (filter_to_do == PNG_FILTER_UP)
+   {
+      png_bytep rp, dp, pp;
+      png_uint_32 i;
+
+      for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
+           pp = prev_row + 1; i < row_bytes;
+           i++, rp++, pp++, dp++)
+      {
+         *dp = (png_byte)(((int)*rp - (int)*pp) & 0xff);
+      }
+      best_row = png_ptr->up_row;
+   }
+
+   else if (filter_to_do & PNG_FILTER_UP)
+   {
+      png_bytep rp, dp, pp;
+      png_uint_32 sum = 0, lmins = mins;
+      png_uint_32 i;
+      int v;
+
+
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+      {
+         int j;
+         png_uint_32 lmhi, lmlo;
+         lmlo = lmins & PNG_LOMASK;
+         lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
+
+         for (j = 0; j < num_p_filters; j++)
+         {
+            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
+            {
+               lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
+                  PNG_WEIGHT_SHIFT;
+               lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
+                  PNG_WEIGHT_SHIFT;
+            }
+         }
+
+         lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
+            PNG_COST_SHIFT;
+         lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_UP]) >>
+            PNG_COST_SHIFT;
+
+         if (lmhi > PNG_HIMASK)
+            lmins = PNG_MAXSUM;
+         else
+            lmins = (lmhi << PNG_HISHIFT) + lmlo;
+      }
+#endif
+
+      for (i = 0, rp = row_buf + 1, dp = png_ptr->up_row + 1,
+           pp = prev_row + 1; i < row_bytes; i++)
+      {
+         v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
+
+         sum += (v < 128) ? v : 256 - v;
+
+         if (sum > lmins)  /* We are already worse, don't continue. */
+            break;
+      }
+
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+      {
+         int j;
+         png_uint_32 sumhi, sumlo;
+         sumlo = sum & PNG_LOMASK;
+         sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
+
+         for (j = 0; j < num_p_filters; j++)
+         {
+            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_UP)
+            {
+               sumlo = (sumlo * png_ptr->filter_weights[j]) >>
+                  PNG_WEIGHT_SHIFT;
+               sumhi = (sumhi * png_ptr->filter_weights[j]) >>
+                  PNG_WEIGHT_SHIFT;
+            }
+         }
+
+         sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
+            PNG_COST_SHIFT;
+         sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_UP]) >>
+            PNG_COST_SHIFT;
+
+         if (sumhi > PNG_HIMASK)
+            sum = PNG_MAXSUM;
+         else
+            sum = (sumhi << PNG_HISHIFT) + sumlo;
+      }
+#endif
+
+      if (sum < mins)
+      {
+         mins = sum;
+         best_row = png_ptr->up_row;
+      }
+   }
+
+   /* avg filter */
+   if (filter_to_do == PNG_FILTER_AVG)
+   {
+      png_bytep rp, dp, pp, lp;
+      png_uint_32 i;
+      for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
+           pp = prev_row + 1; i < bpp; i++)
+      {
+         *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
+      }
+      for (lp = row_buf + 1; i < row_bytes; i++)
+      {
+         *dp++ = (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2))
+                 & 0xff);
+      }
+      best_row = png_ptr->avg_row;
+   }
+
+   else if (filter_to_do & PNG_FILTER_AVG)
+   {
+      png_bytep rp, dp, pp, lp;
+      png_uint_32 sum = 0, lmins = mins;
+      png_uint_32 i;
+      int v;
+
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+      {
+         int j;
+         png_uint_32 lmhi, lmlo;
+         lmlo = lmins & PNG_LOMASK;
+         lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
+
+         for (j = 0; j < num_p_filters; j++)
+         {
+            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_AVG)
+            {
+               lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
+                  PNG_WEIGHT_SHIFT;
+               lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
+                  PNG_WEIGHT_SHIFT;
+            }
+         }
+
+         lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>
+            PNG_COST_SHIFT;
+         lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_AVG]) >>
+            PNG_COST_SHIFT;
+
+         if (lmhi > PNG_HIMASK)
+            lmins = PNG_MAXSUM;
+         else
+            lmins = (lmhi << PNG_HISHIFT) + lmlo;
+      }
+#endif
+
+      for (i = 0, rp = row_buf + 1, dp = png_ptr->avg_row + 1,
+           pp = prev_row + 1; i < bpp; i++)
+      {
+         v = *dp++ = (png_byte)(((int)*rp++ - ((int)*pp++ / 2)) & 0xff);
+
+         sum += (v < 128) ? v : 256 - v;
+      }
+      for (lp = row_buf + 1; i < row_bytes; i++)
+      {
+         v = *dp++ =
+          (png_byte)(((int)*rp++ - (((int)*pp++ + (int)*lp++) / 2)) & 0xff);
+
+         sum += (v < 128) ? v : 256 - v;
+
+         if (sum > lmins)  /* We are already worse, don't continue. */
+            break;
+      }
+
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+      {
+         int j;
+         png_uint_32 sumhi, sumlo;
+         sumlo = sum & PNG_LOMASK;
+         sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
+
+         for (j = 0; j < num_p_filters; j++)
+         {
+            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_NONE)
+            {
+               sumlo = (sumlo * png_ptr->filter_weights[j]) >>
+                  PNG_WEIGHT_SHIFT;
+               sumhi = (sumhi * png_ptr->filter_weights[j]) >>
+                  PNG_WEIGHT_SHIFT;
+            }
+         }
+
+         sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
+            PNG_COST_SHIFT;
+         sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_AVG]) >>
+            PNG_COST_SHIFT;
+
+         if (sumhi > PNG_HIMASK)
+            sum = PNG_MAXSUM;
+         else
+            sum = (sumhi << PNG_HISHIFT) + sumlo;
+      }
+#endif
+
+      if (sum < mins)
+      {
+         mins = sum;
+         best_row = png_ptr->avg_row;
+      }
+   }
+
+   /* Paeth filter */
+   if (filter_to_do == PNG_FILTER_PAETH)
+   {
+      png_bytep rp, dp, pp, cp, lp;
+      png_uint_32 i;
+      for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
+           pp = prev_row + 1; i < bpp; i++)
+      {
+         *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
+      }
+
+      for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
+      {
+         int a, b, c, pa, pb, pc, p;
+
+         b = *pp++;
+         c = *cp++;
+         a = *lp++;
+
+         p = b - c;
+         pc = a - c;
+
+#ifdef PNG_USE_ABS
+         pa = abs(p);
+         pb = abs(pc);
+         pc = abs(p + pc);
+#else
+         pa = p < 0 ? -p : p;
+         pb = pc < 0 ? -pc : pc;
+         pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+#endif
+
+         p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
+
+         *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
+      }
+      best_row = png_ptr->paeth_row;
+   }
+
+   else if (filter_to_do & PNG_FILTER_PAETH)
+   {
+      png_bytep rp, dp, pp, cp, lp;
+      png_uint_32 sum = 0, lmins = mins;
+      png_uint_32 i;
+      int v;
+
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+      {
+         int j;
+         png_uint_32 lmhi, lmlo;
+         lmlo = lmins & PNG_LOMASK;
+         lmhi = (lmins >> PNG_HISHIFT) & PNG_HIMASK;
+
+         for (j = 0; j < num_p_filters; j++)
+         {
+            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
+            {
+               lmlo = (lmlo * png_ptr->inv_filter_weights[j]) >>
+                  PNG_WEIGHT_SHIFT;
+               lmhi = (lmhi * png_ptr->inv_filter_weights[j]) >>
+                  PNG_WEIGHT_SHIFT;
+            }
+         }
+
+         lmlo = (lmlo * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>
+            PNG_COST_SHIFT;
+         lmhi = (lmhi * png_ptr->inv_filter_costs[PNG_FILTER_VALUE_PAETH]) >>
+            PNG_COST_SHIFT;
+
+         if (lmhi > PNG_HIMASK)
+            lmins = PNG_MAXSUM;
+         else
+            lmins = (lmhi << PNG_HISHIFT) + lmlo;
+      }
+#endif
+
+      for (i = 0, rp = row_buf + 1, dp = png_ptr->paeth_row + 1,
+           pp = prev_row + 1; i < bpp; i++)
+      {
+         v = *dp++ = (png_byte)(((int)*rp++ - (int)*pp++) & 0xff);
+
+         sum += (v < 128) ? v : 256 - v;
+      }
+
+      for (lp = row_buf + 1, cp = prev_row + 1; i < row_bytes; i++)
+      {
+         int a, b, c, pa, pb, pc, p;
+
+         b = *pp++;
+         c = *cp++;
+         a = *lp++;
+
+#ifndef PNG_SLOW_PAETH
+         p = b - c;
+         pc = a - c;
+#ifdef PNG_USE_ABS
+         pa = abs(p);
+         pb = abs(pc);
+         pc = abs(p + pc);
+#else
+         pa = p < 0 ? -p : p;
+         pb = pc < 0 ? -pc : pc;
+         pc = (p + pc) < 0 ? -(p + pc) : p + pc;
+#endif
+         p = (pa <= pb && pa <=pc) ? a : (pb <= pc) ? b : c;
+#else /* PNG_SLOW_PAETH */
+         p = a + b - c;
+         pa = abs(p - a);
+         pb = abs(p - b);
+         pc = abs(p - c);
+         if (pa <= pb && pa <= pc)
+            p = a;
+         else if (pb <= pc)
+            p = b;
+         else
+            p = c;
+#endif /* PNG_SLOW_PAETH */
+
+         v = *dp++ = (png_byte)(((int)*rp++ - p) & 0xff);
+
+         sum += (v < 128) ? v : 256 - v;
+
+         if (sum > lmins)  /* We are already worse, don't continue. */
+            break;
+      }
+
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+      if (png_ptr->heuristic_method == PNG_FILTER_HEURISTIC_WEIGHTED)
+      {
+         int j;
+         png_uint_32 sumhi, sumlo;
+         sumlo = sum & PNG_LOMASK;
+         sumhi = (sum >> PNG_HISHIFT) & PNG_HIMASK;
+
+         for (j = 0; j < num_p_filters; j++)
+         {
+            if (png_ptr->prev_filters[j] == PNG_FILTER_VALUE_PAETH)
+            {
+               sumlo = (sumlo * png_ptr->filter_weights[j]) >>
+                  PNG_WEIGHT_SHIFT;
+               sumhi = (sumhi * png_ptr->filter_weights[j]) >>
+                  PNG_WEIGHT_SHIFT;
+            }
+         }
+
+         sumlo = (sumlo * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>
+            PNG_COST_SHIFT;
+         sumhi = (sumhi * png_ptr->filter_costs[PNG_FILTER_VALUE_PAETH]) >>
+            PNG_COST_SHIFT;
+
+         if (sumhi > PNG_HIMASK)
+            sum = PNG_MAXSUM;
+         else
+            sum = (sumhi << PNG_HISHIFT) + sumlo;
+      }
+#endif
+
+      if (sum < mins)
+      {
+         best_row = png_ptr->paeth_row;
+      }
+   }
+#endif /* PNG_NO_WRITE_FILTER */
+   /* Do the actual writing of the filtered row data from the chosen filter. */
+
+   png_write_filtered_row(png_ptr, best_row);
+
+#if defined(PNG_WRITE_WEIGHTED_FILTER_SUPPORTED)
+   /* Save the type of filter we picked this time for future calculations */
+   if (png_ptr->num_prev_filters > 0)
+   {
+      int j;
+      for (j = 1; j < num_p_filters; j++)
+      {
+         png_ptr->prev_filters[j] = png_ptr->prev_filters[j - 1];
+      }
+      png_ptr->prev_filters[j] = best_row[0];
+   }
+#endif
+}
+
+
+/* Do the actual writing of a previously filtered row. */
+void /* PRIVATE */
+png_write_filtered_row(png_structp png_ptr, png_bytep filtered_row)
+{
+   png_debug(1, "in png_write_filtered_row\n");
+   png_debug1(2, "filter = %d\n", filtered_row[0]);
+   /* set up the zlib input buffer */
+
+   png_ptr->zstream.next_in = filtered_row;
+   png_ptr->zstream.avail_in = (uInt)png_ptr->row_info.rowbytes + 1;
+   /* repeat until we have compressed all the data */
+   do
+   {
+      int ret; /* return of zlib */
+
+      /* compress the data */
+      ret = deflate(&png_ptr->zstream, Z_NO_FLUSH);
+      /* check for compression errors */
+      if (ret != Z_OK)
+      {
+         if (png_ptr->zstream.msg != NULL)
+            png_error(png_ptr, png_ptr->zstream.msg);
+         else
+            png_error(png_ptr, "zlib error");
+      }
+
+      /* see if it is time to write another IDAT */
+      if (!(png_ptr->zstream.avail_out))
+      {
+         /* write the IDAT and reset the zlib output buffer */
+         png_write_IDAT(png_ptr, png_ptr->zbuf, png_ptr->zbuf_size);
+         png_ptr->zstream.next_out = png_ptr->zbuf;
+         png_ptr->zstream.avail_out = (uInt)png_ptr->zbuf_size;
+      }
+   /* repeat until all data has been compressed */
+   } while (png_ptr->zstream.avail_in);
+
+   /* swap the current and previous rows */
+   if (png_ptr->prev_row != NULL)
+   {
+      png_bytep tptr;
+
+      tptr = png_ptr->prev_row;
+      png_ptr->prev_row = png_ptr->row_buf;
+      png_ptr->row_buf = tptr;
+   }
+
+   /* finish row - updates counters and flushes zlib if last row */
+   png_write_finish_row(png_ptr);
+
+#if defined(PNG_WRITE_FLUSH_SUPPORTED)
+   png_ptr->flush_rows++;
+
+   if (png_ptr->flush_dist > 0 &&
+       png_ptr->flush_rows >= png_ptr->flush_dist)
+   {
+      png_write_flush(png_ptr);
+   }
+#endif
+}
+#endif /* PNG_WRITE_SUPPORTED */
diff --git a/distrib/libpng-1.2.19/sources.make b/distrib/libpng-1.2.19/sources.make
new file mode 100644
index 0000000..d8088c7
--- /dev/null
+++ b/distrib/libpng-1.2.19/sources.make
@@ -0,0 +1,14 @@
+# this file is included by various Makefiles and defines the set of sources used by our version of LibPng
+#
+LIBPNG_SOURCES := png.c pngerror.c pngget.c pngmem.c pngpread.c pngread.c \
+                  pngrio.c pngrtran.c pngrutil.c pngset.c pngtrans.c pngvcrd.c pngwio.c \
+                  pngwrite.c pngwtran.c pngwutil.c
+
+ifeq ($(HOST_OS),darwin)
+    LIBPNG_CFLAGS += -DPNG_NO_MMX_CODE
+else
+    LIBPNG_SOURCES += pnggccrd.c
+endif
+
+LIBPNG_SOURCES := $(LIBPNG_SOURCES:%=$(LIBPNG_DIR)/%)
+