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ef416fc2 | 1 | /* |
b19ccc9e | 2 | * "$Id: image-gif.c 7720 2008-07-11 22:46:21Z mike $" |
ef416fc2 | 3 | * |
4 | * GIF image routines for the Common UNIX Printing System (CUPS). | |
5 | * | |
91c84a35 | 6 | * Copyright 2007-2008 by Apple Inc. |
c0e1af83 | 7 | * Copyright 1993-2007 by Easy Software Products. |
ef416fc2 | 8 | * |
9 | * These coded instructions, statements, and computer programs are the | |
bc44d920 | 10 | * property of Apple Inc. and are protected by Federal copyright |
11 | * law. Distribution and use rights are outlined in the file "LICENSE.txt" | |
12 | * which should have been included with this file. If this file is | |
13 | * file is missing or damaged, see the license at "http://www.cups.org/". | |
ef416fc2 | 14 | * |
15 | * This file is subject to the Apple OS-Developed Software exception. | |
16 | * | |
17 | * Contents: | |
18 | * | |
19 | * _cupsImageReadGIF() - Read a GIF image file. | |
20 | * gif_get_block() - Read a GIF data block... | |
21 | * gif_get_code() - Get a LZW code from the file... | |
22 | * gif_read_cmap() - Read the colormap from a GIF file... | |
23 | * gif_read_image() - Read a GIF image stream... | |
24 | * gif_read_lzw() - Read a byte from the LZW stream... | |
25 | */ | |
26 | ||
27 | /* | |
28 | * Include necessary headers... | |
29 | */ | |
30 | ||
31 | #include "image-private.h" | |
32 | ||
33 | ||
34 | /* | |
35 | * GIF definitions... | |
36 | */ | |
37 | ||
38 | #define GIF_INTERLACE 0x40 | |
39 | #define GIF_COLORMAP 0x80 | |
839a51c8 | 40 | #define GIF_MAX_BITS 12 |
ef416fc2 | 41 | |
42 | typedef cups_ib_t gif_cmap_t[256][4]; | |
43 | typedef short gif_table_t[4096]; | |
44 | ||
45 | ||
46 | /* | |
47 | * Local globals... | |
48 | */ | |
49 | ||
50 | static int gif_eof = 0; /* Did we hit EOF? */ | |
51 | ||
52 | ||
53 | /* | |
54 | * Local functions... | |
55 | */ | |
56 | ||
57 | static int gif_get_block(FILE *fp, unsigned char *buffer); | |
58 | static int gif_get_code (FILE *fp, int code_size, int first_time); | |
59 | static int gif_read_cmap(FILE *fp, int ncolors, gif_cmap_t cmap, | |
60 | int *gray); | |
61 | static int gif_read_image(FILE *fp, cups_image_t *img, gif_cmap_t cmap, | |
62 | int interlace); | |
63 | static int gif_read_lzw(FILE *fp, int first_time, int input_code_size); | |
64 | ||
65 | ||
66 | /* | |
67 | * '_cupsImageReadGIF()' - Read a GIF image file. | |
68 | */ | |
69 | ||
70 | int /* O - Read status */ | |
71 | _cupsImageReadGIF( | |
72 | cups_image_t *img, /* IO - cupsImage */ | |
73 | FILE *fp, /* I - cupsImage file */ | |
74 | cups_icspace_t primary, /* I - Primary choice for colorspace */ | |
75 | cups_icspace_t secondary, /* I - Secondary choice for colorspace */ | |
76 | int saturation, /* I - Color saturation (%) */ | |
77 | int hue, /* I - Color hue (degrees) */ | |
78 | const cups_ib_t *lut) /* I - Lookup table for gamma/brightness */ | |
79 | { | |
80 | unsigned char buf[1024]; /* Input buffer */ | |
81 | gif_cmap_t cmap; /* Colormap */ | |
82 | int i, /* Looping var */ | |
83 | bpp, /* Bytes per pixel */ | |
84 | gray, /* Grayscale image? */ | |
85 | ncolors, /* Bits per pixel */ | |
86 | transparent; /* Transparent color index */ | |
87 | ||
88 | ||
89 | /* | |
90 | * GIF files are either grayscale or RGB - no CMYK... | |
91 | */ | |
92 | ||
93 | if (primary == CUPS_IMAGE_RGB_CMYK) | |
94 | primary = CUPS_IMAGE_RGB; | |
95 | ||
96 | /* | |
97 | * Read the header; we already know it is a GIF file... | |
98 | */ | |
99 | ||
100 | fread(buf, 13, 1, fp); | |
101 | ||
102 | img->xsize = (buf[7] << 8) | buf[6]; | |
103 | img->ysize = (buf[9] << 8) | buf[8]; | |
104 | ncolors = 2 << (buf[10] & 0x07); | |
105 | gray = primary == CUPS_IMAGE_BLACK || primary == CUPS_IMAGE_WHITE; | |
106 | ||
107 | if (buf[10] & GIF_COLORMAP) | |
108 | if (gif_read_cmap(fp, ncolors, cmap, &gray)) | |
109 | { | |
110 | fclose(fp); | |
111 | return (-1); | |
112 | } | |
113 | ||
114 | transparent = -1; | |
115 | ||
116 | for (;;) | |
117 | { | |
118 | switch (getc(fp)) | |
119 | { | |
120 | case ';' : /* End of image */ | |
121 | fclose(fp); | |
122 | return (-1); /* Early end of file */ | |
123 | ||
124 | case '!' : /* Extension record */ | |
125 | buf[0] = getc(fp); | |
126 | if (buf[0] == 0xf9) /* Graphic Control Extension */ | |
127 | { | |
128 | gif_get_block(fp, buf); | |
129 | if (buf[0] & 1) /* Get transparent color index */ | |
130 | transparent = buf[3]; | |
131 | } | |
132 | ||
133 | while (gif_get_block(fp, buf) != 0); | |
134 | break; | |
135 | ||
136 | case ',' : /* cupsImage data */ | |
137 | fread(buf, 9, 1, fp); | |
138 | ||
139 | if (buf[8] & GIF_COLORMAP) | |
140 | { | |
141 | ncolors = 2 << (buf[8] & 0x07); | |
142 | gray = primary == CUPS_IMAGE_BLACK || primary == CUPS_IMAGE_WHITE; | |
143 | ||
144 | if (gif_read_cmap(fp, ncolors, cmap, &gray)) | |
145 | { | |
146 | fclose(fp); | |
147 | return (-1); | |
148 | } | |
149 | } | |
150 | ||
151 | if (transparent >= 0) | |
152 | { | |
153 | /* | |
154 | * Make transparent color white... | |
155 | */ | |
156 | ||
157 | cmap[transparent][0] = 255; | |
158 | cmap[transparent][1] = 255; | |
159 | cmap[transparent][2] = 255; | |
160 | } | |
161 | ||
162 | if (gray) | |
163 | { | |
164 | switch (secondary) | |
165 | { | |
166 | case CUPS_IMAGE_CMYK : | |
167 | for (i = ncolors - 1; i >= 0; i --) | |
168 | cupsImageWhiteToCMYK(cmap[i], cmap[i], 1); | |
169 | break; | |
170 | case CUPS_IMAGE_CMY : | |
171 | for (i = ncolors - 1; i >= 0; i --) | |
172 | cupsImageWhiteToCMY(cmap[i], cmap[i], 1); | |
173 | break; | |
174 | case CUPS_IMAGE_BLACK : | |
175 | for (i = ncolors - 1; i >= 0; i --) | |
176 | cupsImageWhiteToBlack(cmap[i], cmap[i], 1); | |
177 | break; | |
178 | case CUPS_IMAGE_WHITE : | |
179 | break; | |
180 | case CUPS_IMAGE_RGB : | |
181 | case CUPS_IMAGE_RGB_CMYK : | |
182 | for (i = ncolors - 1; i >= 0; i --) | |
183 | cupsImageWhiteToRGB(cmap[i], cmap[i], 1); | |
184 | break; | |
185 | } | |
186 | ||
187 | img->colorspace = secondary; | |
188 | } | |
189 | else | |
190 | { | |
191 | if (hue != 0 || saturation != 100) | |
192 | for (i = ncolors - 1; i >= 0; i --) | |
193 | cupsImageRGBAdjust(cmap[i], 1, saturation, hue); | |
194 | ||
195 | switch (primary) | |
196 | { | |
197 | case CUPS_IMAGE_CMYK : | |
198 | for (i = ncolors - 1; i >= 0; i --) | |
199 | cupsImageRGBToCMYK(cmap[i], cmap[i], 1); | |
200 | break; | |
201 | case CUPS_IMAGE_CMY : | |
202 | for (i = ncolors - 1; i >= 0; i --) | |
203 | cupsImageRGBToCMY(cmap[i], cmap[i], 1); | |
204 | break; | |
205 | case CUPS_IMAGE_BLACK : | |
206 | for (i = ncolors - 1; i >= 0; i --) | |
207 | cupsImageRGBToBlack(cmap[i], cmap[i], 1); | |
208 | break; | |
209 | case CUPS_IMAGE_WHITE : | |
210 | for (i = ncolors - 1; i >= 0; i --) | |
211 | cupsImageRGBToWhite(cmap[i], cmap[i], 1); | |
212 | break; | |
213 | case CUPS_IMAGE_RGB : | |
214 | case CUPS_IMAGE_RGB_CMYK : | |
f301802f | 215 | for (i = ncolors - 1; i >= 0; i --) |
216 | cupsImageRGBToRGB(cmap[i], cmap[i], 1); | |
ef416fc2 | 217 | break; |
218 | } | |
219 | ||
220 | img->colorspace = primary; | |
221 | } | |
222 | ||
223 | if (lut) | |
224 | { | |
225 | bpp = cupsImageGetDepth(img); | |
226 | ||
227 | for (i = ncolors - 1; i >= 0; i --) | |
228 | cupsImageLut(cmap[i], bpp, lut); | |
229 | } | |
230 | ||
231 | img->xsize = (buf[5] << 8) | buf[4]; | |
232 | img->ysize = (buf[7] << 8) | buf[6]; | |
233 | ||
234 | /* | |
235 | * Check the dimensions of the image; since the dimensions are | |
236 | * a 16-bit integer we just need to check for 0... | |
237 | */ | |
238 | ||
239 | if (img->xsize == 0 || img->ysize == 0) | |
240 | { | |
c0e1af83 | 241 | fprintf(stderr, "DEBUG: Bad GIF image dimensions: %dx%d\n", |
ef416fc2 | 242 | img->xsize, img->ysize); |
243 | fclose(fp); | |
244 | return (1); | |
245 | } | |
246 | ||
247 | i = gif_read_image(fp, img, cmap, buf[8] & GIF_INTERLACE); | |
248 | fclose(fp); | |
249 | return (i); | |
250 | } | |
251 | } | |
252 | } | |
253 | ||
254 | ||
255 | /* | |
256 | * 'gif_get_block()' - Read a GIF data block... | |
257 | */ | |
258 | ||
259 | static int /* O - Number characters read */ | |
260 | gif_get_block(FILE *fp, /* I - File to read from */ | |
261 | unsigned char *buf) /* I - Input buffer */ | |
262 | { | |
263 | int count; /* Number of character to read */ | |
264 | ||
265 | ||
266 | /* | |
267 | * Read the count byte followed by the data from the file... | |
268 | */ | |
269 | ||
270 | if ((count = getc(fp)) == EOF) | |
271 | { | |
272 | gif_eof = 1; | |
273 | return (-1); | |
274 | } | |
275 | else if (count == 0) | |
276 | gif_eof = 1; | |
277 | else if (fread(buf, 1, count, fp) < count) | |
278 | { | |
279 | gif_eof = 1; | |
280 | return (-1); | |
281 | } | |
282 | else | |
283 | gif_eof = 0; | |
284 | ||
285 | return (count); | |
286 | } | |
287 | ||
288 | ||
289 | /* | |
290 | * 'gif_get_code()' - Get a LZW code from the file... | |
291 | */ | |
292 | ||
293 | static int /* O - LZW code */ | |
294 | gif_get_code(FILE *fp, /* I - File to read from */ | |
295 | int code_size, /* I - Size of code in bits */ | |
296 | int first_time) /* I - 1 = first time, 0 = not first time */ | |
297 | { | |
298 | unsigned i, j, /* Looping vars */ | |
299 | ret; /* Return value */ | |
300 | int count; /* Number of bytes read */ | |
301 | static unsigned char buf[280]; /* Input buffer */ | |
302 | static unsigned curbit, /* Current bit */ | |
303 | lastbit, /* Last bit in buffer */ | |
304 | done, /* Done with this buffer? */ | |
305 | last_byte; /* Last byte in buffer */ | |
306 | static const unsigned char bits[8] = /* Bit masks for codes */ | |
307 | { | |
308 | 0x01, 0x02, 0x04, 0x08, | |
309 | 0x10, 0x20, 0x40, 0x80 | |
310 | }; | |
311 | ||
312 | ||
313 | if (first_time) | |
314 | { | |
315 | /* | |
316 | * Just initialize the input buffer... | |
317 | */ | |
318 | ||
319 | curbit = 0; | |
320 | lastbit = 0; | |
321 | last_byte = 0; | |
322 | done = 0; | |
323 | ||
324 | return (0); | |
325 | } | |
326 | ||
327 | if ((curbit + code_size) >= lastbit) | |
328 | { | |
329 | /* | |
330 | * Don't have enough bits to hold the code... | |
331 | */ | |
332 | ||
333 | if (done) | |
334 | return (-1); /* Sorry, no more... */ | |
335 | ||
336 | /* | |
337 | * Move last two bytes to front of buffer... | |
338 | */ | |
339 | ||
340 | if (last_byte > 1) | |
341 | { | |
342 | buf[0] = buf[last_byte - 2]; | |
343 | buf[1] = buf[last_byte - 1]; | |
344 | last_byte = 2; | |
345 | } | |
346 | else if (last_byte == 1) | |
347 | { | |
348 | buf[0] = buf[last_byte - 1]; | |
349 | last_byte = 1; | |
350 | } | |
351 | ||
352 | /* | |
353 | * Read in another buffer... | |
354 | */ | |
355 | ||
356 | if ((count = gif_get_block (fp, buf + last_byte)) <= 0) | |
357 | { | |
358 | /* | |
359 | * Whoops, no more data! | |
360 | */ | |
361 | ||
362 | done = 1; | |
363 | return (-1); | |
364 | } | |
365 | ||
366 | /* | |
367 | * Update buffer state... | |
368 | */ | |
369 | ||
370 | curbit = (curbit - lastbit) + 8 * last_byte; | |
371 | last_byte += count; | |
372 | lastbit = last_byte * 8; | |
373 | } | |
374 | ||
ef416fc2 | 375 | for (ret = 0, i = curbit + code_size - 1, j = code_size; |
376 | j > 0; | |
377 | i --, j --) | |
378 | ret = (ret << 1) | ((buf[i / 8] & bits[i & 7]) != 0); | |
379 | ||
380 | curbit += code_size; | |
381 | ||
382 | return ret; | |
383 | } | |
384 | ||
385 | ||
386 | /* | |
387 | * 'gif_read_cmap()' - Read the colormap from a GIF file... | |
388 | */ | |
389 | ||
390 | static int /* O - -1 on error, 0 on success */ | |
391 | gif_read_cmap(FILE *fp, /* I - File to read from */ | |
392 | int ncolors, /* I - Number of colors in file */ | |
393 | gif_cmap_t cmap, /* O - Colormap information */ | |
394 | int *gray) /* IO - Is the image grayscale? */ | |
395 | { | |
396 | int i; /* Looping var */ | |
397 | ||
398 | ||
399 | /* | |
400 | * Read the colormap... | |
401 | */ | |
402 | ||
403 | for (i = 0; i < ncolors; i ++) | |
404 | if (fread(cmap[i], 3, 1, fp) < 1) | |
405 | return (-1); | |
406 | ||
407 | /* | |
408 | * Check to see if the colormap is a grayscale ramp... | |
409 | */ | |
410 | ||
411 | for (i = 0; i < ncolors; i ++) | |
412 | if (cmap[i][0] != cmap[i][1] || cmap[i][1] != cmap[i][2]) | |
413 | break; | |
414 | ||
415 | if (i == ncolors) | |
416 | { | |
417 | *gray = 1; | |
418 | return (0); | |
419 | } | |
420 | ||
421 | /* | |
422 | * If this needs to be a grayscale image, convert the RGB values to | |
423 | * luminance values... | |
424 | */ | |
425 | ||
426 | if (*gray) | |
427 | for (i = 0; i < ncolors; i ++) | |
428 | cmap[i][0] = (cmap[i][0] * 31 + cmap[i][1] * 61 + cmap[i][2] * 8) / 100; | |
429 | ||
430 | return (0); | |
431 | } | |
432 | ||
433 | ||
434 | /* | |
435 | * 'gif_read_image()' - Read a GIF image stream... | |
436 | */ | |
437 | ||
438 | static int /* I - 0 = success, -1 = failure */ | |
439 | gif_read_image(FILE *fp, /* I - Input file */ | |
440 | cups_image_t *img, /* I - cupsImage pointer */ | |
441 | gif_cmap_t cmap, /* I - Colormap */ | |
442 | int interlace) /* I - Non-zero = interlaced image */ | |
443 | { | |
444 | unsigned char code_size; /* Code size */ | |
445 | cups_ib_t *pixels, /* Pixel buffer */ | |
446 | *temp; /* Current pixel */ | |
447 | int xpos, /* Current X position */ | |
448 | ypos, /* Current Y position */ | |
449 | pass; /* Current pass */ | |
450 | int pixel; /* Current pixel */ | |
451 | int bpp; /* Bytes per pixel */ | |
452 | static const int xpasses[4] = /* X interleaving */ | |
453 | { 8, 8, 4, 2 }, | |
454 | ypasses[5] = /* Y interleaving */ | |
455 | { 0, 4, 2, 1, 999999 }; | |
456 | ||
457 | ||
458 | bpp = cupsImageGetDepth(img); | |
459 | pixels = calloc(bpp, img->xsize); | |
460 | xpos = 0; | |
461 | ypos = 0; | |
462 | pass = 0; | |
463 | code_size = getc(fp); | |
464 | ||
839a51c8 | 465 | if (code_size > GIF_MAX_BITS || !pixels) |
91c84a35 MS |
466 | return (-1); |
467 | ||
ef416fc2 | 468 | if (gif_read_lzw(fp, 1, code_size) < 0) |
91c84a35 MS |
469 | { |
470 | free(pixels); | |
ef416fc2 | 471 | return (-1); |
91c84a35 | 472 | } |
ef416fc2 | 473 | |
474 | temp = pixels; | |
475 | while ((pixel = gif_read_lzw(fp, 0, code_size)) >= 0) | |
476 | { | |
477 | switch (bpp) | |
478 | { | |
479 | case 4 : | |
480 | temp[3] = cmap[pixel][3]; | |
481 | case 3 : | |
482 | temp[2] = cmap[pixel][2]; | |
483 | case 2 : | |
484 | temp[1] = cmap[pixel][1]; | |
485 | default : | |
486 | temp[0] = cmap[pixel][0]; | |
487 | } | |
488 | ||
489 | xpos ++; | |
490 | temp += bpp; | |
491 | if (xpos == img->xsize) | |
492 | { | |
493 | _cupsImagePutRow(img, 0, ypos, img->xsize, pixels); | |
494 | ||
495 | xpos = 0; | |
496 | temp = pixels; | |
497 | ||
498 | if (interlace) | |
499 | { | |
500 | ypos += xpasses[pass]; | |
501 | ||
502 | if (ypos >= img->ysize) | |
503 | { | |
504 | pass ++; | |
505 | ||
506 | ypos = ypasses[pass]; | |
507 | } | |
508 | } | |
509 | else | |
510 | ypos ++; | |
511 | } | |
512 | ||
513 | if (ypos >= img->ysize) | |
514 | break; | |
515 | } | |
516 | ||
517 | free(pixels); | |
518 | ||
519 | return (0); | |
520 | } | |
521 | ||
522 | ||
523 | /* | |
524 | * 'gif_read_lzw()' - Read a byte from the LZW stream... | |
525 | */ | |
526 | ||
527 | static int /* I - Byte from stream */ | |
528 | gif_read_lzw(FILE *fp, /* I - File to read from */ | |
529 | int first_time, /* I - 1 = first time, 0 = not first time */ | |
530 | int input_code_size) /* I - Code size in bits */ | |
531 | { | |
532 | int i, /* Looping var */ | |
533 | code, /* Current code */ | |
534 | incode; /* Input code */ | |
535 | static short fresh = 0, /* 1 = empty buffers */ | |
536 | code_size, /* Current code size */ | |
537 | set_code_size, /* Initial code size set */ | |
538 | max_code, /* Maximum code used */ | |
539 | max_code_size, /* Maximum code size */ | |
540 | firstcode, /* First code read */ | |
541 | oldcode, /* Last code read */ | |
542 | clear_code, /* Clear code for LZW input */ | |
543 | end_code, /* End code for LZW input */ | |
544 | *stack = NULL, /* Output stack */ | |
545 | *sp; /* Current stack pointer */ | |
546 | static gif_table_t *table = NULL; /* String table */ | |
547 | ||
548 | ||
549 | if (first_time) | |
550 | { | |
551 | /* | |
552 | * Setup LZW state... | |
553 | */ | |
554 | ||
555 | set_code_size = input_code_size; | |
556 | code_size = set_code_size + 1; | |
557 | clear_code = 1 << set_code_size; | |
558 | end_code = clear_code + 1; | |
559 | max_code_size = 2 * clear_code; | |
560 | max_code = clear_code + 2; | |
561 | ||
562 | /* | |
563 | * Allocate memory for buffers... | |
564 | */ | |
565 | ||
566 | if (table == NULL) | |
567 | table = calloc(2, sizeof(gif_table_t)); | |
568 | ||
569 | if (table == NULL) | |
570 | return (-1); | |
571 | ||
572 | if (stack == NULL) | |
573 | stack = calloc(8192, sizeof(short)); | |
574 | ||
575 | if (stack == NULL) | |
576 | return (-1); | |
577 | ||
578 | /* | |
579 | * Initialize input buffers... | |
580 | */ | |
581 | ||
582 | gif_get_code(fp, 0, 1); | |
583 | ||
584 | /* | |
585 | * Wipe the decompressor table... | |
586 | */ | |
587 | ||
588 | fresh = 1; | |
589 | ||
590 | for (i = 0; i < clear_code; i ++) | |
591 | { | |
592 | table[0][i] = 0; | |
593 | table[1][i] = i; | |
594 | } | |
595 | ||
596 | for (; i < 4096; i ++) | |
597 | table[0][i] = table[1][0] = 0; | |
598 | ||
599 | sp = stack; | |
600 | ||
601 | return (0); | |
602 | } | |
603 | else if (fresh) | |
604 | { | |
605 | fresh = 0; | |
606 | ||
607 | do | |
608 | firstcode = oldcode = gif_get_code(fp, code_size, 0); | |
609 | while (firstcode == clear_code); | |
610 | ||
611 | return (firstcode); | |
612 | } | |
1f0275e3 MS |
613 | else if (!table) |
614 | return (0); | |
ef416fc2 | 615 | |
616 | if (sp > stack) | |
617 | return (*--sp); | |
618 | ||
619 | while ((code = gif_get_code (fp, code_size, 0)) >= 0) | |
620 | { | |
621 | if (code == clear_code) | |
622 | { | |
623 | for (i = 0; i < clear_code; i ++) | |
624 | { | |
625 | table[0][i] = 0; | |
626 | table[1][i] = i; | |
627 | } | |
628 | ||
629 | for (; i < 4096; i ++) | |
630 | table[0][i] = table[1][i] = 0; | |
631 | ||
632 | code_size = set_code_size + 1; | |
633 | max_code_size = 2 * clear_code; | |
634 | max_code = clear_code + 2; | |
635 | ||
636 | sp = stack; | |
637 | ||
638 | firstcode = oldcode = gif_get_code(fp, code_size, 0); | |
639 | ||
640 | return (firstcode); | |
641 | } | |
642 | else if (code == end_code) | |
643 | { | |
644 | unsigned char buf[260]; | |
645 | ||
646 | ||
647 | if (!gif_eof) | |
648 | while (gif_get_block(fp, buf) > 0); | |
649 | ||
650 | return (-2); | |
651 | } | |
652 | ||
653 | incode = code; | |
654 | ||
655 | if (code >= max_code) | |
656 | { | |
657 | *sp++ = firstcode; | |
658 | code = oldcode; | |
659 | } | |
660 | ||
661 | while (code >= clear_code) | |
662 | { | |
663 | *sp++ = table[1][code]; | |
664 | if (code == table[0][code]) | |
665 | return (255); | |
666 | ||
667 | code = table[0][code]; | |
668 | } | |
669 | ||
670 | *sp++ = firstcode = table[1][code]; | |
671 | code = max_code; | |
672 | ||
673 | if (code < 4096) | |
674 | { | |
675 | table[0][code] = oldcode; | |
676 | table[1][code] = firstcode; | |
677 | max_code ++; | |
678 | ||
679 | if (max_code >= max_code_size && max_code_size < 4096) | |
680 | { | |
681 | max_code_size *= 2; | |
682 | code_size ++; | |
683 | } | |
684 | } | |
685 | ||
686 | oldcode = incode; | |
687 | ||
688 | if (sp > stack) | |
689 | return (*--sp); | |
690 | } | |
691 | ||
692 | return (code); | |
693 | } | |
694 | ||
695 | ||
696 | /* | |
b19ccc9e | 697 | * End of "$Id: image-gif.c 7720 2008-07-11 22:46:21Z mike $". |
ef416fc2 | 698 | */ |