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bcf6c51c4c
1999-10-30 <jrb@redhat.com> * src/io-gif.c: Some more work. Now it generates a gdk_pixbuf of the right size, at a minimum, even if the image is squished and the wrong color.
584 lines
13 KiB
C
584 lines
13 KiB
C
/* GdkPixbuf library - GIF image loader
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*
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* Copyright (C) 1999 Mark Crichton
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* Copyright (C) 1999 The Free Software Foundation
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*
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* Authors: Jonathan Blandford <jrb@redhat.com>
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* Adapted from the gimp gif filter written by Adam Moss <adam@gimp.org>
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* Gimp work based on earlier work by ......
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* Permission to relicense under the LGPL obtained.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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#include <config.h>
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#include <stdio.h>
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#include <glib.h>
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#include <gif_lib.h>
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#include <string.h>
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#include "gdk-pixbuf.h"
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#include "gdk-pixbuf-io.h"
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#define MAXCOLORMAPSIZE 256
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#define CM_RED 0
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#define CM_GREEN 1
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#define CM_BLUE 2
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#define MAX_LWZ_BITS 12
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#define INTERLACE 0x40
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#define LOCALCOLORMAP 0x80
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#define BitSet(byte, bit) (((byte) & (bit)) == (bit))
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#define ReadOK(file,buffer,len) (fread(buffer, len, 1, file) != 0)
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#define LM_to_uint(a,b) (((b)<<8)|(a))
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#define GRAYSCALE 1
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#define COLOR 2
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typedef unsigned char CMap[3][MAXCOLORMAPSIZE];
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typedef struct _Gif89 Gif89;
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struct _Gif89
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{
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int transparent;
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int delay_time;
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int input_flag;
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int disposal;
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};
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typedef struct _GifContext GifContext;
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struct _GifContext
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{
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unsigned int width;
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unsigned int height;
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CMap color_map;
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unsigned int bit_pixel;
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unsigned int color_resolution;
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unsigned int background;
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unsigned int aspect_ratio;
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int gray_scale;
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GdkPixbuf *pixbuf;
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guchar used_cmap[3][256];
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Gif89 gif89;
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};
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int verbose = FALSE;
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int showComment = TRUE;
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char *globalcomment = NULL;
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gint globalusecomment = TRUE;
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static int ReadColorMap (FILE *, int, CMap, int *);
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static int DoExtension (FILE *file, GifContext *context, int label);
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static int GetDataBlock (FILE *, unsigned char *);
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static int GetCode (FILE *, int, int);
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static int LWZReadByte (FILE *, int, int);
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static void ReadImage (FILE *file,
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GifContext *context,
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int len,
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int height,
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CMap cmap,
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int ncols,
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int format,
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int interlace,
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int number,
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guint leftpos,
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guint toppos);
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static int
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ReadColorMap (FILE *file,
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int number,
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CMap buffer,
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int *format)
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{
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int i;
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unsigned char rgb[3];
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int flag;
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flag = TRUE;
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for (i = 0; i < number; ++i) {
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if (!ReadOK (file, rgb, sizeof (rgb))) {
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/*g_message (_("GIF: bad colormap\n"));*/
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return TRUE;
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}
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buffer[CM_RED][i] = rgb[0];
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buffer[CM_GREEN][i] = rgb[1];
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buffer[CM_BLUE][i] = rgb[2];
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flag &= (rgb[0] == rgb[1] && rgb[1] == rgb[2]);
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}
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*format = (flag) ? GRAYSCALE : COLOR;
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return FALSE;
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}
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static int
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DoExtension (FILE *file, GifContext *context, int label)
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{
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static guchar buf[256];
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switch (label) {
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case 0xf9: /* Graphic Control Extension */
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(void) GetDataBlock (file, (unsigned char *) buf);
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context->gif89.disposal = (buf[0] >> 2) & 0x7;
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context->gif89.input_flag = (buf[0] >> 1) & 0x1;
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context->gif89.delay_time = LM_to_uint (buf[1], buf[2]);
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if (context->pixbuf == NULL) {
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/* I only want to set the transparency if I haven't
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* created the pixbuf yet. */
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if ((buf[0] & 0x1) != 0)
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context->gif89.transparent = buf[3];
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else
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context->gif89.transparent = -1;
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}
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while (GetDataBlock (file, (unsigned char *) buf) != 0)
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;
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return FALSE;
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break;
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default:
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/* Unhandled extension */
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break;
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}
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while (GetDataBlock (file, (unsigned char *) buf) != 0)
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;
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return FALSE;
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}
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int ZeroDataBlock = FALSE;
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static int
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GetDataBlock (FILE *file,
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unsigned char *buf)
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{
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unsigned char count;
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if (!ReadOK (file, &count, 1)) {
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/*g_message (_("GIF: error in getting DataBlock size\n"));*/
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return -1;
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}
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ZeroDataBlock = count == 0;
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if ((count != 0) && (!ReadOK (file, buf, count))) {
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/*g_message (_("GIF: error in reading DataBlock\n"));*/
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return -1;
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}
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return count;
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}
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static int
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GetCode (FILE *file,
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int code_size,
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int flag)
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{
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static unsigned char buf[280];
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static int curbit, lastbit, done, last_byte;
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int i, j, ret;
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unsigned char count;
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if (flag) {
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curbit = 0;
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lastbit = 0;
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done = FALSE;
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return 0;
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}
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if ((curbit + code_size) >= lastbit){
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if (done) {
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if (curbit >= lastbit) {
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/*g_message (_("GIF: ran off the end of by bits\n"));*/
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return -1;
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}
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return -1;
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}
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buf[0] = buf[last_byte - 2];
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buf[1] = buf[last_byte - 1];
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if ((count = GetDataBlock (file, &buf[2])) == 0)
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done = TRUE;
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last_byte = 2 + count;
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curbit = (curbit - lastbit) + 16;
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lastbit = (2 + count) * 8;
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}
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ret = 0;
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for (i = curbit, j = 0; j < code_size; ++i, ++j)
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ret |= ((buf[i / 8] & (1 << (i % 8))) != 0) << j;
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curbit += code_size;
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return ret;
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}
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static int
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LWZReadByte (FILE *file,
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int flag,
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int input_code_size)
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{
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static int fresh = FALSE;
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int code, incode;
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static int code_size, set_code_size;
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static int max_code, max_code_size;
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static int firstcode, oldcode;
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static int clear_code, end_code;
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static int table[2][(1 << MAX_LWZ_BITS)];
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static int stack[(1 << (MAX_LWZ_BITS)) * 2], *sp;
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register int i;
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if (flag) {
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set_code_size = input_code_size;
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code_size = set_code_size + 1;
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clear_code = 1 << set_code_size;
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end_code = clear_code + 1;
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max_code_size = 2 * clear_code;
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max_code = clear_code + 2;
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GetCode (file, 0, TRUE);
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fresh = TRUE;
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for (i = 0; i < clear_code; ++i) {
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table[0][i] = 0;
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table[1][i] = i;
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}
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for (; i < (1 << MAX_LWZ_BITS); ++i)
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table[0][i] = table[1][0] = 0;
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sp = stack;
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return 0;
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} else if (fresh) {
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fresh = FALSE;
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do {
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firstcode = oldcode = GetCode (file, code_size, FALSE);
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} while (firstcode == clear_code);
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return firstcode;
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}
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if (sp > stack)
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return *--sp;
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while ((code = GetCode (file, code_size, FALSE)) >= 0) {
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if (code == clear_code) {
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for (i = 0; i < clear_code; ++i) {
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table[0][i] = 0;
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table[1][i] = i;
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}
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for (; i < (1 << MAX_LWZ_BITS); ++i)
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table[0][i] = table[1][i] = 0;
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code_size = set_code_size + 1;
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max_code_size = 2 * clear_code;
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max_code = clear_code + 2;
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sp = stack;
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firstcode = oldcode =
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GetCode (file, code_size, FALSE);
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return firstcode;
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} else if (code == end_code) {
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int count;
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unsigned char buf[260];
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if (ZeroDataBlock)
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return -2;
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while ((count = GetDataBlock (file, buf)) > 0)
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;
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if (count != 0)
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/*g_print (_("GIF: missing EOD in data stream (common occurence)"));*/
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return -2;
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}
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incode = code;
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if (code >= max_code) {
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*sp++ = firstcode;
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code = oldcode;
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}
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while (code >= clear_code) {
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*sp++ = table[1][code];
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if (code == table[0][code]) {
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/*g_message (_("GIF: circular table entry BIG ERROR\n"));*/
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/*gimp_quit ();*/
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return -1;
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}
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code = table[0][code];
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}
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*sp++ = firstcode = table[1][code];
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if ((code = max_code) < (1 << MAX_LWZ_BITS)) {
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table[0][code] = oldcode;
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table[1][code] = firstcode;
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++max_code;
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if ((max_code >= max_code_size) &&
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(max_code_size < (1 << MAX_LWZ_BITS))) {
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max_code_size *= 2;
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++code_size;
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}
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}
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oldcode = incode;
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if (sp > stack)
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return *--sp;
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}
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return code;
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}
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static void
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ReadImage (FILE *file,
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GifContext *context,
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int len,
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int height,
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CMap cmap,
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int ncols,
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int format,
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int interlace,
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int number,
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guint leftpos,
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guint toppos)
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{
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guchar *dest, *temp;
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guchar c;
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gint xpos = 0, ypos = 0, pass = 0;
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gint v;
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gint i, j;
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/*
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** Initialize the Compression routines
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*/
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if (!ReadOK (file, &c, 1)) {
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/*g_message (_("GIF: EOF / read error on image data\n"));*/
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return;
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}
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if (LWZReadByte (file, TRUE, c) < 0) {
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/*g_message (_("GIF: error while reading\n"));*/
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return;
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}
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context->pixbuf = gdk_pixbuf_new (ART_PIX_RGB,
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context->gif89.transparent,
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8,
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context->width,
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context->height);
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for (i = 0, j = 0; i < ncols; i++) {
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context->used_cmap[0][i] = cmap[0][i];
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context->used_cmap[1][i] = cmap[1][i];
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context->used_cmap[2][i] = cmap[2][i];
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}
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dest = gdk_pixbuf_get_pixels (context->pixbuf);
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while ((v = LWZReadByte (file, FALSE, c)) >= 0) {
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if (context->gif89.transparent) {
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temp = dest + ( (ypos * len) + xpos ) * 2;
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*temp = (guchar) v;
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*(temp+1) = (guchar) ((v == context->gif89.transparent) ? 0 : 255);
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} else {
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temp = dest + (ypos * len) + xpos;
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*temp = (guchar) v;
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}
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xpos++;
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if (xpos == len) {
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xpos = 0;
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if (interlace) {
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switch (pass) {
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case 0:
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case 1:
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ypos += 8;
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break;
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case 2:
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ypos += 4;
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break;
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case 3:
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ypos += 2;
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break;
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}
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if (ypos >= height) {
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pass++;
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switch (pass) {
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case 1:
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ypos = 4;
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break;
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case 2:
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ypos = 2;
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break;
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case 3:
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ypos = 1;
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break;
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default:
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goto fini;
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}
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}
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} else {
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ypos++;
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}
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}
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if (ypos >= height)
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break;
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}
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fini:
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if (LWZReadByte (file, FALSE, c) >= 0)
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g_print ("GIF: too much input data, ignoring extra...\n");
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}
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|
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/* Shared library entry point */
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GdkPixbuf *
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image_load (FILE *file)
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{
|
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unsigned char buf[16];
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unsigned char c;
|
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CMap localColorMap;
|
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int useGlobalColormap;
|
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int bitPixel;
|
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int imageCount = 0;
|
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char version[4];
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GifContext *context;
|
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|
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g_return_val_if_fail (file != NULL, NULL);
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|
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context = g_new (GifContext, 1);
|
||
|
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if (!ReadOK (file, buf, 6)) {
|
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/* Unable to read magic number */
|
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return NULL;
|
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}
|
||
|
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if (strncmp ((char *) buf, "GIF", 3) != 0) {
|
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/* Not a GIF file */
|
||
return NULL;
|
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}
|
||
|
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strncpy (version, (char *) buf + 3, 3);
|
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version[3] = '\0';
|
||
|
||
if ((strcmp (version, "87a") != 0) && (strcmp (version, "89a") != 0)) {
|
||
/* bad version number, not '87a' or '89a' */
|
||
return NULL;
|
||
}
|
||
|
||
/* read the screen descriptor */
|
||
if (!ReadOK (file, buf, 7)) {
|
||
/* Failed to read screen descriptor */
|
||
return NULL;
|
||
}
|
||
|
||
context->width = LM_to_uint (buf[0], buf[1]);
|
||
context->height = LM_to_uint (buf[2], buf[3]);
|
||
context->bit_pixel = 2 << (buf[4] & 0x07);
|
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context->color_resolution = (((buf[4] & 0x70) >> 3) + 1);
|
||
context->background = buf[5];
|
||
context->aspect_ratio = buf[6];
|
||
context->pixbuf = NULL;
|
||
|
||
if (BitSet (buf[4], LOCALCOLORMAP)) {
|
||
/* Global Colormap */
|
||
if (ReadColorMap (file, context->bit_pixel,
|
||
context->color_map,
|
||
&context->gray_scale)) {
|
||
g_free (context);
|
||
return NULL;
|
||
}
|
||
}
|
||
|
||
if (context->aspect_ratio != 0 && context->aspect_ratio != 49) {
|
||
/*g_message (_("GIF: warning - non-square pixels\n"));*/
|
||
}
|
||
|
||
for (;;) {
|
||
if (!ReadOK (file, &c, 1)) {
|
||
/*g_message (_("GIF: EOF / read error on image data\n"));*/
|
||
return context->pixbuf;
|
||
}
|
||
|
||
if (c == ';') {
|
||
/* GIF terminator */
|
||
return context->pixbuf;
|
||
}
|
||
|
||
if (c == '!') {
|
||
/* Extension */
|
||
if (!ReadOK (file, &c, 1)) {
|
||
/*g_message (_("GIF: EOF / read error on extension function code\n"));*/
|
||
return context->pixbuf; /* will be -1 if failed on first image! */
|
||
}
|
||
DoExtension (file, context, c);
|
||
continue;
|
||
}
|
||
|
||
if (c != ',') {
|
||
/* Not a valid start character */
|
||
/*g_message (_("GIF: bogus character 0x%02x, ignoring\n"), (int) c);*/
|
||
continue;
|
||
}
|
||
|
||
++imageCount;
|
||
|
||
if (!ReadOK (file, buf, 9)) {
|
||
/*g_message (_("GIF: couldn't read left/top/width/height\n"));*/
|
||
return context->pixbuf; /* will be -1 if failed on first image! */
|
||
}
|
||
|
||
useGlobalColormap = !BitSet (buf[8], LOCALCOLORMAP);
|
||
|
||
bitPixel = 1 << ((buf[8] & 0x07) + 1);
|
||
|
||
if (!useGlobalColormap) {
|
||
if (ReadColorMap (file, bitPixel, localColorMap, &context->gray_scale)) {
|
||
/*g_message (_("GIF: error reading local colormap\n"));*/
|
||
return context->pixbuf; /* will be -1 if failed on first image! */
|
||
}
|
||
ReadImage (file, context, LM_to_uint (buf[4], buf[5]),
|
||
LM_to_uint (buf[6], buf[7]),
|
||
localColorMap, bitPixel,
|
||
context->gray_scale,
|
||
BitSet (buf[8], INTERLACE), imageCount,
|
||
(guint) LM_to_uint (buf[0], buf[1]),
|
||
(guint) LM_to_uint (buf[2], buf[3]));
|
||
} else {
|
||
ReadImage (file, context, LM_to_uint (buf[4], buf[5]),
|
||
LM_to_uint (buf[6], buf[7]),
|
||
context->color_map, context->bit_pixel,
|
||
context->gray_scale,
|
||
BitSet (buf[8], INTERLACE), imageCount,
|
||
(guint) LM_to_uint (buf[0], buf[1]),
|
||
(guint) LM_to_uint (buf[2], buf[3]));
|
||
}
|
||
}
|
||
|
||
return context->pixbuf;
|
||
}
|
||
|
||
|
||
|