1 /* GIF reading routines based on those in pbmplus:ppm/giftoppm.c, bearing
2 * following copyright notice:
3 */
4
5 /* +-------------------------------------------------------------------+ */
6 /* | Copyright 1990, David Koblas. | */
7 /* | Permission to use, copy, modify, and distribute this software | */
8 /* | and its documentation for any purpose and without fee is hereby | */
9 /* | granted, provided that the above copyright notice appear in all | */
10 /* | copies and that both that copyright notice and this permission | */
11 /* | notice appear in supporting documentation. This software is | */
12 /* | provided "as is" without express or implied warranty. | */
13 /* +-------------------------------------------------------------------+ */
14
15
16 #include "config.h"
17 #include "tile.h"
18
19 #ifndef MONITOR_HEAP
20 extern long *FDECL(alloc, (unsigned int));
21 #endif
22
23 #define PPM_ASSIGN(p,red,grn,blu) do { (p).r = (red); (p).g = (grn); (p).b = (blu); } while ( 0 )
24
25 #define MAX_LWZ_BITS 12
26
27 #define INTERLACE 0x40
28 #define LOCALCOLORMAP 0x80
29 #define BitSet(byte, bit) (((byte) & (bit)) == (bit))
30
31 #define ReadOK(file,buffer,len) (fread((genericptr_t)buffer, (int)len, 1, file) != 0)
32
33 #define LM_to_uint(a,b) (((b)<<8)|(a))
34
35 struct gifscreen {
36 int Width;
37 int Height;
38 int Colors;
39 int ColorResolution;
40 int Background;
41 int AspectRatio;
42 int Interlace;
43 } GifScreen;
44
45 struct {
46 int transparent;
47 int delayTime;
48 int inputFlag;
49 int disposal;
50 } Gif89 = { -1, -1, -1, 0 };
51
52 int ZeroDataBlock = FALSE;
53
54 static FILE *gif_file;
55 static int tiles_across, tiles_down, curr_tiles_across, curr_tiles_down;
56 static pixel **image;
57 static unsigned char input_code_size;
58
59 static int FDECL(GetDataBlock, (FILE *fd, unsigned char *buf));
60 static void FDECL(DoExtension, (FILE *fd, int label));
61 static boolean FDECL(ReadColorMap, (FILE *fd, int number));
62 static void FDECL(read_header, (FILE *fd));
63 static int FDECL(GetCode, (FILE *fd, int code_size, int flag));
64 static int FDECL(LWZReadByte, (FILE *fd, int flag, int input_code_size));
65 static void FDECL(ReadInterleavedImage, (FILE *fd, int len, int height));
66 static void FDECL(ReadTileStrip, (FILE *fd, int len));
67
68 /* These should be in gif.h, but there isn't one. */
69 boolean FDECL(fopen_gif_file, (const char *, const char *));
70 boolean FDECL(read_gif_tile, (pixel(*)[]));
71 int NDECL(fclose_gif_file);
72
73 static int
GetDataBlock(fd,buf)74 GetDataBlock(fd, buf)
75 FILE *fd;
76 unsigned char *buf;
77 {
78 unsigned char count;
79
80 if (!ReadOK(fd,&count,1)) {
81 Fprintf(stderr, "error in getting DataBlock size\n");
82 return -1;
83 }
84
85 ZeroDataBlock = (count == 0);
86
87 if ((count != 0) && (!ReadOK(fd, buf, count))) {
88 Fprintf(stderr, "error in reading DataBlock\n");
89 return -1;
90 }
91
92 return count;
93 }
94
95 static void
DoExtension(fd,label)96 DoExtension(fd, label)
97 FILE *fd;
98 int label;
99 {
100 static char buf[256];
101 char *str;
102
103 switch (label) {
104 case 0x01: /* Plain Text Extension */
105 str = "Plain Text Extension";
106 #ifdef notdef
107 if (GetDataBlock(fd, (unsigned char*) buf) == 0)
108 ;
109
110 lpos = LM_to_uint(buf[0], buf[1]);
111 tpos = LM_to_uint(buf[2], buf[3]);
112 width = LM_to_uint(buf[4], buf[5]);
113 height = LM_to_uint(buf[6], buf[7]);
114 cellw = buf[8];
115 cellh = buf[9];
116 foreground = buf[10];
117 background = buf[11];
118
119 while (GetDataBlock(fd, (unsigned char*) buf) != 0) {
120 PPM_ASSIGN(image[ypos][xpos],
121 cmap[CM_RED][v],
122 cmap[CM_GREEN][v],
123 cmap[CM_BLUE][v]);
124 ++index;
125 }
126
127 return;
128 #else
129 break;
130 #endif
131 case 0xff: /* Application Extension */
132 str = "Application Extension";
133 break;
134 case 0xfe: /* Comment Extension */
135 str = "Comment Extension";
136 while (GetDataBlock(fd, (unsigned char*) buf) != 0) {
137 Fprintf(stderr, "gif comment: %s\n", buf );
138 }
139 return;
140 case 0xf9: /* Graphic Control Extension */
141 str = "Graphic Control Extension";
142 (void) GetDataBlock(fd, (unsigned char*) buf);
143 Gif89.disposal = (buf[0] >> 2) & 0x7;
144 Gif89.inputFlag = (buf[0] >> 1) & 0x1;
145 Gif89.delayTime = LM_to_uint(buf[1],buf[2]);
146 if ((buf[0] & 0x1) != 0)
147 Gif89.transparent = buf[3];
148
149 while (GetDataBlock(fd, (unsigned char*) buf) != 0)
150 ;
151 return;
152 default:
153 str = buf;
154 Sprintf(buf, "UNKNOWN (0x%02x)", label);
155 break;
156 }
157
158 Fprintf(stderr, "got a '%s' extension\n", str);
159
160 while (GetDataBlock(fd, (unsigned char*) buf) != 0)
161 ;
162 }
163
164 static
165 boolean
ReadColorMap(fd,number)166 ReadColorMap(fd,number)
167 FILE *fd;
168 int number;
169 {
170 int i;
171 unsigned char rgb[3];
172
173 for (i = 0; i < number; ++i) {
174 if (!ReadOK(fd, rgb, sizeof(rgb))) {
175 return(FALSE);
176 }
177
178 ColorMap[CM_RED][i] = rgb[0] ;
179 ColorMap[CM_GREEN][i] = rgb[1] ;
180 ColorMap[CM_BLUE][i] = rgb[2] ;
181 }
182 colorsinmap = number;
183 return TRUE;
184 }
185
186 /*
187 * Read gif header, including colormaps. We expect only one image per
188 * file, so if that image has a local colormap, overwrite the global one.
189 */
190 static void
read_header(fd)191 read_header(fd)
192 FILE *fd;
193 {
194 unsigned char buf[16];
195 unsigned char c;
196 char version[4];
197
198 if (!ReadOK(fd,buf,6)) {
199 Fprintf(stderr, "error reading magic number\n");
200 exit(EXIT_FAILURE);
201 }
202
203 if (strncmp((genericptr_t)buf,"GIF",3) != 0) {
204 Fprintf(stderr, "not a GIF file\n");
205 exit(EXIT_FAILURE);
206 }
207
208 (void) strncpy(version, (char *)buf + 3, 3);
209 version[3] = '\0';
210
211 if ((strcmp(version, "87a") != 0) && (strcmp(version, "89a") != 0)) {
212 Fprintf(stderr, "bad version number, not '87a' or '89a'\n");
213 exit(EXIT_FAILURE);
214 }
215
216 if (!ReadOK(fd,buf,7)) {
217 Fprintf(stderr, "failed to read screen descriptor\n");
218 exit(EXIT_FAILURE);
219 }
220
221 GifScreen.Width = LM_to_uint(buf[0],buf[1]);
222 GifScreen.Height = LM_to_uint(buf[2],buf[3]);
223 GifScreen.Colors = 2<<(buf[4]&0x07);
224 GifScreen.ColorResolution = (((buf[4]&0x70)>>3)+1);
225 GifScreen.Background = buf[5];
226 GifScreen.AspectRatio = buf[6];
227
228 if (BitSet(buf[4], LOCALCOLORMAP)) { /* Global Colormap */
229 if (!ReadColorMap(fd, GifScreen.Colors)) {
230 Fprintf(stderr, "error reading global colormap\n");
231 exit(EXIT_FAILURE);
232 }
233 }
234
235 if (GifScreen.AspectRatio != 0 && GifScreen.AspectRatio != 49) {
236 Fprintf(stderr, "warning - non-square pixels\n");
237 }
238
239 for (;;) {
240 if (!ReadOK(fd,&c,1)) {
241 Fprintf(stderr, "EOF / read error on image data\n");
242 exit(EXIT_FAILURE);
243 }
244
245 if (c == ';') { /* GIF terminator */
246 return;
247 }
248
249 if (c == '!') { /* Extension */
250 if (!ReadOK(fd,&c,1)) {
251 Fprintf(stderr,
252 "EOF / read error on extension function code\n");
253 exit(EXIT_FAILURE);
254 }
255 DoExtension(fd, (int)c);
256 continue;
257 }
258
259 if (c != ',') { /* Not a valid start character */
260 Fprintf(stderr,
261 "bogus character 0x%02x, ignoring\n", (int) c);
262 continue;
263 }
264
265 if (!ReadOK(fd,buf,9)) {
266 Fprintf(stderr, "couldn't read left/top/width/height\n");
267 exit(EXIT_FAILURE);
268 }
269
270 if (BitSet(buf[8], LOCALCOLORMAP)) {
271 /* replace global color map with local */
272 GifScreen.Colors = 1<<((buf[8]&0x07)+1);
273 if (!ReadColorMap(fd, GifScreen.Colors)) {
274 Fprintf(stderr, "error reading local colormap\n");
275 exit(EXIT_FAILURE);
276 }
277
278 }
279 if (GifScreen.Width != LM_to_uint(buf[4],buf[5])) {
280 Fprintf(stderr, "warning: widths don't match\n");
281 GifScreen.Width = LM_to_uint(buf[4],buf[5]);
282 }
283 if (GifScreen.Height != LM_to_uint(buf[6],buf[7])) {
284 Fprintf(stderr, "warning: heights don't match\n");
285 GifScreen.Height = LM_to_uint(buf[6],buf[7]);
286 }
287 GifScreen.Interlace = BitSet(buf[8], INTERLACE);
288 return;
289 }
290 }
291
292 static int
GetCode(fd,code_size,flag)293 GetCode(fd, code_size, flag)
294 FILE *fd;
295 int code_size;
296 int flag;
297 {
298 static unsigned char buf[280];
299 static int curbit, lastbit, done, last_byte;
300 int i, j, ret;
301 unsigned char count;
302
303 if (flag) {
304 curbit = 0;
305 lastbit = 0;
306 done = FALSE;
307 return 0;
308 }
309
310 if ((curbit+code_size) >= lastbit) {
311 if (done) {
312 if (curbit >= lastbit)
313 Fprintf(stderr, "ran off the end of my bits\n");
314 return -1;
315 }
316 buf[0] = buf[last_byte-2];
317 buf[1] = buf[last_byte-1];
318
319 if ((count = GetDataBlock(fd, &buf[2])) == 0)
320 done = TRUE;
321
322 last_byte = 2 + count;
323 curbit = (curbit - lastbit) + 16;
324 lastbit = (2+count)*8 ;
325 }
326
327 ret = 0;
328 for (i = curbit, j = 0; j < code_size; ++i, ++j)
329 ret |= ((buf[ i / 8 ] & (1 << (i % 8))) != 0) << j;
330
331 curbit += code_size;
332
333 return ret;
334 }
335
336 static int
LWZReadByte(fd,flag,input_code_size)337 LWZReadByte(fd, flag, input_code_size)
338 FILE *fd;
339 int flag;
340 int input_code_size;
341 {
342 static int fresh = FALSE;
343 int code, incode;
344 static int code_size, set_code_size;
345 static int max_code, max_code_size;
346 static int firstcode, oldcode;
347 static int clear_code, end_code;
348 static int table[2][(1<< MAX_LWZ_BITS)];
349 static int stack[(1<<(MAX_LWZ_BITS))*2], *sp;
350 register int i;
351
352 if (flag) {
353 set_code_size = input_code_size;
354 code_size = set_code_size+1;
355 clear_code = 1 << set_code_size ;
356 end_code = clear_code + 1;
357 max_code_size = 2*clear_code;
358 max_code = clear_code+2;
359
360 (void) GetCode(fd, 0, TRUE);
361
362 fresh = TRUE;
363
364 for (i = 0; i < clear_code; ++i) {
365 table[0][i] = 0;
366 table[1][i] = i;
367 }
368 for (; i < (1<<MAX_LWZ_BITS); ++i)
369 table[0][i] = table[1][0] = 0;
370
371 sp = stack;
372
373 return 0;
374 } else if (fresh) {
375 fresh = FALSE;
376 do {
377 firstcode = oldcode = GetCode(fd, code_size, FALSE);
378 } while (firstcode == clear_code);
379 return firstcode;
380 }
381
382 if (sp > stack)
383 return *--sp;
384
385 while ((code = GetCode(fd, code_size, FALSE)) >= 0) {
386 if (code == clear_code) {
387 for (i = 0; i < clear_code; ++i) {
388 table[0][i] = 0;
389 table[1][i] = i;
390 }
391 for (; i < (1<<MAX_LWZ_BITS); ++i)
392 table[0][i] = table[1][i] = 0;
393 code_size = set_code_size+1;
394 max_code_size = 2*clear_code;
395 max_code = clear_code+2;
396 sp = stack;
397 firstcode = oldcode = GetCode(fd, code_size, FALSE);
398 return firstcode;
399 } else if (code == end_code) {
400 int count;
401 unsigned char buf[260];
402
403 if (ZeroDataBlock)
404 return -2;
405
406 while ((count = GetDataBlock(fd, buf)) > 0)
407 ;
408
409 if (count != 0)
410 Fprintf(stderr,
411 "missing EOD in data stream (common occurrence)\n");
412 return -2;
413 }
414
415 incode = code;
416
417 if (code >= max_code) {
418 *sp++ = firstcode;
419 code = oldcode;
420 }
421
422 while (code >= clear_code) {
423 *sp++ = table[1][code];
424 if (code == table[0][code]) {
425 Fprintf(stderr, "circular table entry BIG ERROR\n");
426 exit(EXIT_FAILURE);
427 }
428 code = table[0][code];
429 }
430
431 *sp++ = firstcode = table[1][code];
432
433 if ((code = max_code) <(1<<MAX_LWZ_BITS)) {
434 table[0][code] = oldcode;
435 table[1][code] = firstcode;
436 ++max_code;
437 if ((max_code >= max_code_size) &&
438 (max_code_size < (1<<MAX_LWZ_BITS))) {
439 max_code_size *= 2;
440 ++code_size;
441 }
442 }
443
444 oldcode = incode;
445
446 if (sp > stack)
447 return *--sp;
448 }
449 return code;
450 }
451
452
453 static void
ReadInterleavedImage(fd,len,height)454 ReadInterleavedImage(fd, len, height)
455 FILE *fd;
456 int len, height;
457 {
458 int v;
459 int xpos = 0, ypos = 0, pass = 0;
460
461 while ((v = LWZReadByte(fd,FALSE,(int)input_code_size)) >= 0 ) {
462 PPM_ASSIGN(image[ypos][xpos], ColorMap[CM_RED][v],
463 ColorMap[CM_GREEN][v], ColorMap[CM_BLUE][v]);
464
465 ++xpos;
466 if (xpos == len) {
467 xpos = 0;
468 switch (pass) {
469 case 0:
470 case 1:
471 ypos += 8; break;
472 case 2:
473 ypos += 4; break;
474 case 3:
475 ypos += 2; break;
476 }
477
478 if (ypos >= height) {
479 ++pass;
480 switch (pass) {
481 case 1:
482 ypos = 4; break;
483 case 2:
484 ypos = 2; break;
485 case 3:
486 ypos = 1; break;
487 default:
488 goto fini;
489 }
490 }
491 }
492 if (ypos >= height)
493 break;
494 }
495
496 fini:
497 if (LWZReadByte(fd,FALSE,(int)input_code_size)>=0)
498 Fprintf(stderr, "too much input data, ignoring extra...\n");
499 }
500
501 static
502 void
ReadTileStrip(fd,len)503 ReadTileStrip(fd,len)
504 FILE *fd;
505 int len;
506 {
507 int v;
508 int xpos = 0, ypos = 0;
509
510 while ((v = LWZReadByte(fd,FALSE,(int)input_code_size)) >= 0 ) {
511 PPM_ASSIGN(image[ypos][xpos], ColorMap[CM_RED][v],
512 ColorMap[CM_GREEN][v], ColorMap[CM_BLUE][v]);
513
514 ++xpos;
515 if (xpos == len) {
516 xpos = 0;
517 ++ypos;
518 }
519 if (ypos >= TILE_Y)
520 break;
521 }
522 }
523
524
525
526
527 boolean
fopen_gif_file(filename,type)528 fopen_gif_file(filename, type)
529 const char *filename;
530 const char *type;
531 {
532 int i;
533
534 if (strcmp(type, RDBMODE)) {
535 Fprintf(stderr, "using reading routine for non-reading?\n");
536 return FALSE;
537 }
538 gif_file = fopen(filename, type);
539 if (gif_file == (FILE *)0) {
540 Fprintf(stderr, "cannot open gif file %s\n", filename);
541 return FALSE;
542 }
543
544 read_header(gif_file);
545 if (GifScreen.Width % TILE_X) {
546 Fprintf(stderr, "error: width %d not divisible by %d\n",
547 GifScreen.Width, TILE_X);
548 exit(EXIT_FAILURE);
549 }
550 tiles_across = GifScreen.Width / TILE_X;
551 curr_tiles_across = 0;
552 if (GifScreen.Height % TILE_Y) {
553 Fprintf(stderr, "error: height %d not divisible by %d\n",
554 GifScreen.Height, TILE_Y);
555 /* exit(EXIT_FAILURE) */;
556 }
557 tiles_down = GifScreen.Height / TILE_Y;
558 curr_tiles_down = 0;
559
560 if (GifScreen.Interlace) {
561 /* sigh -- hope this doesn't happen on micros */
562 image = (pixel **)alloc(GifScreen.Height * sizeof(pixel *));
563 for (i = 0; i < GifScreen.Height; i++) {
564 image[i] = (pixel *) alloc(GifScreen.Width * sizeof(pixel));
565 }
566 } else {
567 image = (pixel **)alloc(TILE_Y * sizeof(pixel *));
568 for (i = 0; i < TILE_Y; i++) {
569 image[i] = (pixel *) alloc(GifScreen.Width * sizeof(pixel));
570 }
571 }
572
573 /*
574 ** Initialize the Compression routines
575 */
576 if (!ReadOK(gif_file,&input_code_size,1)) {
577 Fprintf(stderr, "EOF / read error on image data\n");
578 exit(EXIT_FAILURE);
579 }
580
581 if (LWZReadByte(gif_file, TRUE, (int)input_code_size) < 0) {
582 Fprintf(stderr, "error reading image\n");
583 exit(EXIT_FAILURE);
584 }
585
586 /* read first section */
587 if (GifScreen.Interlace) {
588 ReadInterleavedImage(gif_file,
589 GifScreen.Width,GifScreen.Height);
590 } else {
591 ReadTileStrip(gif_file,GifScreen.Width);
592 }
593 return TRUE;
594 }
595
596 /* Read a tile. Returns FALSE when there are no more tiles */
597 boolean
598 read_gif_tile(pixels)
599 pixel (*pixels)[TILE_X];
600 {
601 int i, j;
602
603 if (curr_tiles_down >= tiles_down) return FALSE;
604 if (curr_tiles_across == tiles_across) {
605 curr_tiles_across = 0;
606 curr_tiles_down++;
607 if (curr_tiles_down >= tiles_down) return FALSE;
608 if (!GifScreen.Interlace)
609 ReadTileStrip(gif_file,GifScreen.Width);
610 }
611 if (GifScreen.Interlace) {
612 for (j = 0; j < TILE_Y; j++) {
613 for (i = 0; i < TILE_X; i++) {
614 pixels[j][i] = image[curr_tiles_down*TILE_Y + j]
615 [curr_tiles_across*TILE_X + i];
616 }
617 }
618 } else {
619 for (j = 0; j < TILE_Y; j++) {
620 for (i = 0; i < TILE_X; i++) {
621 pixels[j][i] = image[j][curr_tiles_across*TILE_X + i];
622 }
623 }
624 }
625 curr_tiles_across++;
626
627 /* check for "filler" tile */
628 for (j = 0; j < TILE_Y; j++) {
629 for (i = 0; i < TILE_X && i < 4; i += 2) {
630 if (pixels[j][i].r != ColorMap[CM_RED][0] ||
631 pixels[j][i].g != ColorMap[CM_GREEN][0] ||
632 pixels[j][i].b != ColorMap[CM_BLUE][0] ||
633 pixels[j][i+1].r != ColorMap[CM_RED][1] ||
634 pixels[j][i+1].g != ColorMap[CM_GREEN][1] ||
635 pixels[j][i+1].b != ColorMap[CM_BLUE][1])
636 return TRUE;
637 }
638 }
639 return FALSE;
640 }
641
642 int
fclose_gif_file()643 fclose_gif_file()
644 {
645 int i;
646
647 if (GifScreen.Interlace) {
648 for (i = 0; i < GifScreen.Height; i++) {
649 free((genericptr_t)image[i]);
650 }
651 free((genericptr_t)image);
652 } else {
653 for (i = 0; i < TILE_Y; i++) {
654 free((genericptr_t)image[i]);
655 }
656 free((genericptr_t)image);
657 }
658 return(fclose(gif_file));
659 }
660
661 #ifndef AMIGA
662 static char *std_args[] = { "tilemap", /* dummy argv[0] */
663 "monsters.gif", "monsters.txt",
664 "objects.gif", "objects.txt",
665 "other.gif", "other.txt" };
666
667 int
main(argc,argv)668 main(argc, argv)
669 int argc;
670 char *argv[];
671 {
672 pixel pixels[TILE_Y][TILE_X];
673
674 if (argc == 1) {
675 argc = SIZE(std_args);
676 argv = std_args;
677 } else if (argc != 3) {
678 Fprintf(stderr, "usage: gif2txt giffile txtfile\n");
679 exit(EXIT_FAILURE);
680 }
681
682 while (argc > 1) {
683 if (!fopen_gif_file(argv[1], RDBMODE))
684 exit(EXIT_FAILURE);
685
686 init_colormap();
687
688 if (!fopen_text_file(argv[2], WRTMODE)) {
689 (void) fclose_gif_file();
690 exit(EXIT_FAILURE);
691 }
692
693 while (read_gif_tile(pixels))
694 (void) write_text_tile(pixels);
695
696 (void) fclose_gif_file();
697 (void) fclose_text_file();
698
699 argc -= 2;
700 argv += 2;
701 }
702 exit(EXIT_SUCCESS);
703 /*NOTREACHED*/
704 return 0;
705 }
706 #endif
707