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Diffstat (limited to 'WebCore/platform/image-decoders/gif/GIFImageReader.h')
| -rw-r--r-- | WebCore/platform/image-decoders/gif/GIFImageReader.h | 214 |
1 files changed, 214 insertions, 0 deletions
diff --git a/WebCore/platform/image-decoders/gif/GIFImageReader.h b/WebCore/platform/image-decoders/gif/GIFImageReader.h new file mode 100644 index 0000000..faa08d2 --- /dev/null +++ b/WebCore/platform/image-decoders/gif/GIFImageReader.h @@ -0,0 +1,214 @@ +/* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* ***** BEGIN LICENSE BLOCK ***** + * Version: MPL 1.1/GPL 2.0/LGPL 2.1 + * + * The contents of this file are subject to the Mozilla Public License Version + * 1.1 (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * http://www.mozilla.org/MPL/ + * + * Software distributed under the License is distributed on an "AS IS" basis, + * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License + * for the specific language governing rights and limitations under the + * License. + * + * The Original Code is Mozilla Communicator client code. + * + * The Initial Developer of the Original Code is + * Netscape Communications Corporation. + * Portions created by the Initial Developer are Copyright (C) 1998 + * the Initial Developer. All Rights Reserved. + * + * Contributor(s): + * + * Alternatively, the contents of this file may be used under the terms of + * either the GNU General Public License Version 2 or later (the "GPL"), or + * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), + * in which case the provisions of the GPL or the LGPL are applicable instead + * of those above. If you wish to allow use of your version of this file only + * under the terms of either the GPL or the LGPL, and not to allow others to + * use your version of this file under the terms of the MPL, indicate your + * decision by deleting the provisions above and replace them with the notice + * and other provisions required by the GPL or the LGPL. If you do not delete + * the provisions above, a recipient may use your version of this file under + * the terms of any one of the MPL, the GPL or the LGPL. + * + * ***** END LICENSE BLOCK ***** */ + +#ifndef _GIF_H_ +#define _GIF_H_ + +// Define ourselves as the clientPtr. Mozilla just hacked their C++ callback class into this old C decoder, +// so we will too. +#include "GIFImageDecoder.h" + +#define MAX_LZW_BITS 12 +#define MAX_BITS 4097 /* 2^MAX_LZW_BITS+1 */ +#define MAX_COLORS 256 +#define MAX_HOLD_SIZE 256 + +/* gif2.h + The interface for the GIF87/89a decoder. +*/ +// List of possible parsing states +typedef enum { + gif_type, + gif_global_header, + gif_global_colormap, + gif_image_start, + gif_image_header, + gif_image_colormap, + gif_image_body, + gif_lzw_start, + gif_lzw, + gif_sub_block, + gif_extension, + gif_control_extension, + gif_consume_block, + gif_skip_block, + gif_done, + gif_oom, + gif_error, + gif_comment_extension, + gif_application_extension, + gif_netscape_extension_block, + gif_consume_netscape_extension, + gif_consume_comment +} gstate; + +struct GIFFrameReader { + /* LZW decoder state machine */ + unsigned char *stackp; /* Current stack pointer */ + int datasize; + int codesize; + int codemask; + int clear_code; /* Codeword used to trigger dictionary reset */ + int avail; /* Index of next available slot in dictionary */ + int oldcode; + unsigned char firstchar; + int bits; /* Number of unread bits in "datum" */ + int datum; /* 32-bit input buffer */ + + /* Output state machine */ + int ipass; /* Interlace pass; Ranges 1-4 if interlaced. */ + unsigned int rows_remaining; /* Rows remaining to be output */ + unsigned int irow; /* Current output row, starting at zero */ + unsigned char *rowbuf; /* Single scanline temporary buffer */ + unsigned char *rowend; /* Pointer to end of rowbuf */ + unsigned char *rowp; /* Current output pointer */ + + /* Parameters for image frame currently being decoded */ + unsigned int x_offset, y_offset; /* With respect to "screen" origin */ + unsigned int height, width; + int tpixel; /* Index of transparent pixel */ + WebCore::RGBA32Buffer::FrameDisposalMethod disposal_method; /* Restore to background, leave in place, etc.*/ + unsigned char *local_colormap; /* Per-image colormap */ + int local_colormap_size; /* Size of local colormap array. */ + + bool is_local_colormap_defined : 1; + bool progressive_display : 1; /* If TRUE, do Haeberli interlace hack */ + bool interlaced : 1; /* TRUE, if scanlines arrive interlaced order */ + bool is_transparent : 1; /* TRUE, if tpixel is valid */ + + unsigned delay_time; /* Display time, in milliseconds, + for this image in a multi-image GIF */ + + + unsigned short* prefix; /* LZW decoding tables */ + unsigned char* suffix; /* LZW decoding tables */ + unsigned char* stack; /* Base of LZW decoder stack */ + + + GIFFrameReader() { + stackp = 0; + datasize = codesize = codemask = clear_code = avail = oldcode = 0; + firstchar = 0; + bits = datum = 0; + ipass = 0; + rows_remaining = irow = 0; + rowbuf = rowend = rowp = 0; + + x_offset = y_offset = width = height = 0; + tpixel = 0; + disposal_method = WebCore::RGBA32Buffer::DisposeNotSpecified; + + local_colormap = 0; + local_colormap_size = 0; + is_local_colormap_defined = progressive_display = is_transparent = interlaced = false; + + delay_time = 0; + + prefix = 0; + suffix = stack = 0; + } + + ~GIFFrameReader() { + delete []rowbuf; + delete []local_colormap; + delete []prefix; + delete []suffix; + delete []stack; + } +}; + +struct GIFImageReader { + WebCore::GIFImageDecoder* clientptr; + /* Parsing state machine */ + gstate state; /* Current decoder master state */ + unsigned bytes_to_consume; /* Number of bytes to accumulate */ + unsigned bytes_in_hold; /* bytes accumulated so far*/ + unsigned char hold[MAX_HOLD_SIZE]; /* Accumulation buffer */ + unsigned char* global_colormap; /* (3* MAX_COLORS in size) Default colormap if local not supplied, 3 bytes for each color */ + + /* Global (multi-image) state */ + int screen_bgcolor; /* Logical screen background color */ + int version; /* Either 89 for GIF89 or 87 for GIF87 */ + unsigned screen_width; /* Logical screen width & height */ + unsigned screen_height; + int global_colormap_size; /* Size of global colormap array. */ + int images_decoded; /* Counts completed frames for animated GIFs */ + int images_count; /* Counted all frames seen so far (including incomplete frames) */ + int loop_count; /* Netscape specific extension block to control + the number of animation loops a GIF renders. */ + + // Not really global, but convenient to locate here. + int count; /* Remaining # bytes in sub-block */ + + GIFFrameReader* frame_reader; + + GIFImageReader(WebCore::GIFImageDecoder* client = 0) { + clientptr = client; + state = gif_type; + bytes_to_consume = 6; + bytes_in_hold = 0; + frame_reader = 0; + global_colormap = 0; + + screen_bgcolor = version = 0; + screen_width = screen_height = 0; + global_colormap_size = images_decoded = images_count = 0; + loop_count = -1; + count = 0; + } + + ~GIFImageReader() { + close(); + } + + void close() { + delete []global_colormap; + global_colormap = 0; + delete frame_reader; + frame_reader = 0; + } + + bool read(const unsigned char * buf, unsigned int numbytes, + WebCore::GIFImageDecoder::GIFQuery query = WebCore::GIFImageDecoder::GIFFullQuery, unsigned haltAtFrame = -1); + +private: + void output_row(); + int do_lzw(const unsigned char *q); +}; + +#endif + |