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/* -*- 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 GIFImageReader_h
#define GIFImageReader_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
const int cLoopCountNotSeen = -2;
/* 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. */
unsigned 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 = cLoopCountNotSeen;
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:
bool output_row();
bool do_lzw(const unsigned char *q);
};
#endif
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