win/share/gifread.c

   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  * $ANH-Date: 1432512803 2015/05/25 00:13:23 $  $ANH-Branch: master $:$ANH-Revision: 1.5 $
  17  */
  18
  19 #include "config.h"
  20 #include "tile.h"
  21
  22 #ifndef MONITOR_HEAP
  23 extern long *FDECL(alloc, (unsigned int));
  24 #endif
  25
  26 #define PPM_ASSIGN(p, red, grn, blu) \
  27     do {                             \
  28         (p).r = (red);               \
  29         (p).g = (grn);               \
  30         (p).b = (blu);               \
  31     } while (0)
  32
  33 #define MAX_LWZ_BITS 12
  34
  35 #define INTERLACE 0x40
  36 #define LOCALCOLORMAP 0x80
  37 #define BitSet(byte, bit) (((byte) & (bit)) == (bit))
  38
  39 #define ReadOK(file, buffer, len) \
  40     (fread((genericptr_t) buffer, (int) len, 1, file) != 0)
  41
  42 #define LM_to_uint(a, b) (((b) << 8) | (a))
  43
  44 struct gifscreen {
  45     int Width;
  46     int Height;
  47     int Colors;
  48     int ColorResolution;
  49     int Background;
  50     int AspectRatio;
  51     int Interlace;
  52 } GifScreen;
  53
  54 struct {
  55     int transparent;
  56     int delayTime;
  57     int inputFlag;
  58     int disposal;
  59 } Gif89 = { -1, -1, -1, 0 };
  60
  61 int ZeroDataBlock = FALSE;
  62
  63 static FILE *gif_file;
  64 static int tiles_across, tiles_down, curr_tiles_across, curr_tiles_down;
  65 static pixel **image;
  66 static unsigned char input_code_size;
  67
  68 static int FDECL(GetDataBlock, (FILE * fd, unsigned char *buf));
  69 static void FDECL(DoExtension, (FILE * fd, int label));
  70 static boolean FDECL(ReadColorMap, (FILE * fd, int number));
  71 static void FDECL(read_header, (FILE * fd));
  72 static int FDECL(GetCode, (FILE * fd, int code_size, int flag));
  73 static int FDECL(LWZReadByte, (FILE * fd, int flag, int input_code_size));
  74 static void FDECL(ReadInterleavedImage, (FILE * fd, int len, int height));
  75 static void FDECL(ReadTileStrip, (FILE * fd, int len));
  76
  77 /* These should be in gif.h, but there isn't one. */
  78 boolean FDECL(fopen_gif_file, (const char *, const char *));
  79 boolean FDECL(read_gif_tile, (pixel(*) [TILE_X]));
  80 int NDECL(fclose_gif_file);
  81
  82 static int
  83 GetDataBlock(fd, buf)
  84 FILE *fd;
  85 unsigned char *buf;
  86 {
  87     unsigned char count;
  88
  89     if (!ReadOK(fd, &count, 1)) {
  90         Fprintf(stderr, "error in getting DataBlock size\n");
  91         return -1;
  92     }
  93
  94     ZeroDataBlock = (count == 0);
  95
  96     if ((count != 0) && (!ReadOK(fd, buf, count))) {
  97         Fprintf(stderr, "error in reading DataBlock\n");
  98         return -1;
  99     }
 100
 101     return count;
 102 }
 103
 104 static void
 105 DoExtension(fd, label)
 106 FILE *fd;
 107 int label;
 108 {
 109     static char buf[256];
 110     char *str;
 111
 112     switch (label) {
 113     case 0x01: /* Plain Text Extension */
 114         str = "Plain Text Extension";
 115 #ifdef notdef
 116         if (GetDataBlock(fd, (unsigned char *) buf) == 0)
 117             ;
 118
 119         lpos = LM_to_uint(buf[0], buf[1]);
 120         tpos = LM_to_uint(buf[2], buf[3]);
 121         width = LM_to_uint(buf[4], buf[5]);
 122         height = LM_to_uint(buf[6], buf[7]);
 123         cellw = buf[8];
 124         cellh = buf[9];
 125         foreground = buf[10];
 126         background = buf[11];
 127
 128         while (GetDataBlock(fd, (unsigned char *) buf) != 0) {
 129             PPM_ASSIGN(image[ypos][xpos], cmap[CM_RED][v], cmap[CM_GREEN][v],
 130                        cmap[CM_BLUE][v]);
 131             ++index;
 132         }
 133
 134         return;
 135 #else
 136         break;
 137 #endif
 138     case 0xff: /* Application Extension */
 139         str = "Application Extension";
 140         break;
 141     case 0xfe: /* Comment Extension */
 142         str = "Comment Extension";
 143         while (GetDataBlock(fd, (unsigned char *) buf) != 0) {
 144             Fprintf(stderr, "gif comment: %s\n", buf);
 145         }
 146         return;
 147     case 0xf9: /* Graphic Control Extension */
 148         str = "Graphic Control Extension";
 149         (void) GetDataBlock(fd, (unsigned char *) buf);
 150         Gif89.disposal = (buf[0] >> 2) & 0x7;
 151         Gif89.inputFlag = (buf[0] >> 1) & 0x1;
 152         Gif89.delayTime = LM_to_uint(buf[1], buf[2]);
 153         if ((buf[0] & 0x1) != 0)
 154             Gif89.transparent = buf[3];
 155
 156         while (GetDataBlock(fd, (unsigned char *) buf) != 0)
 157             ;
 158         return;
 159     default:
 160         str = buf;
 161         Sprintf(buf, "UNKNOWN (0x%02x)", label);
 162         break;
 163     }
 164
 165     Fprintf(stderr, "got a '%s' extension\n", str);
 166
 167     while (GetDataBlock(fd, (unsigned char *) buf) != 0)
 168         ;
 169 }
 170
 171 static boolean
 172 ReadColorMap(fd, number)
 173 FILE *fd;
 174 int number;
 175 {
 176     int i;
 177     unsigned char rgb[3];
 178
 179     for (i = 0; i < number; ++i) {
 180         if (!ReadOK(fd, rgb, sizeof(rgb))) {
 181             return (FALSE);
 182         }
 183
 184         ColorMap[CM_RED][i] = rgb[0];
 185         ColorMap[CM_GREEN][i] = rgb[1];
 186         ColorMap[CM_BLUE][i] = rgb[2];
 187     }
 188     colorsinmap = number;
 189     return TRUE;
 190 }
 191
 192 /*
 193  * Read gif header, including colormaps.  We expect only one image per
 194  * file, so if that image has a local colormap, overwrite the global one.
 195  */
 196 static void
 197 read_header(fd)
 198 FILE *fd;
 199 {
 200     unsigned char buf[16];
 201     unsigned char c;
 202     char version[4];
 203
 204     if (!ReadOK(fd, buf, 6)) {
 205         Fprintf(stderr, "error reading magic number\n");
 206         exit(EXIT_FAILURE);
 207     }
 208
 209     if (strncmp((genericptr_t) buf, "GIF", 3) != 0) {
 210         Fprintf(stderr, "not a GIF file\n");
 211         exit(EXIT_FAILURE);
 212     }
 213
 214     (void) strncpy(version, (char *) buf + 3, 3);
 215     version[3] = '\0';
 216
 217     if ((strcmp(version, "87a") != 0) && (strcmp(version, "89a") != 0)) {
 218         Fprintf(stderr, "bad version number, not '87a' or '89a'\n");
 219         exit(EXIT_FAILURE);
 220     }
 221
 222     if (!ReadOK(fd, buf, 7)) {
 223         Fprintf(stderr, "failed to read screen descriptor\n");
 224         exit(EXIT_FAILURE);
 225     }
 226
 227     GifScreen.Width = LM_to_uint(buf[0], buf[1]);
 228     GifScreen.Height = LM_to_uint(buf[2], buf[3]);
 229     GifScreen.Colors = 2 << (buf[4] & 0x07);
 230     GifScreen.ColorResolution = (((buf[4] & 0x70) >> 3) + 1);
 231     GifScreen.Background = buf[5];
 232     GifScreen.AspectRatio = buf[6];
 233
 234     if (BitSet(buf[4], LOCALCOLORMAP)) { /* Global Colormap */
 235         if (!ReadColorMap(fd, GifScreen.Colors)) {
 236             Fprintf(stderr, "error reading global colormap\n");
 237             exit(EXIT_FAILURE);
 238         }
 239     }
 240
 241     if (GifScreen.AspectRatio != 0 && GifScreen.AspectRatio != 49) {
 242         Fprintf(stderr, "warning - non-square pixels\n");
 243     }
 244
 245     for (;;) {
 246         if (!ReadOK(fd, &c, 1)) {
 247             Fprintf(stderr, "EOF / read error on image data\n");
 248             exit(EXIT_FAILURE);
 249         }
 250
 251         if (c == ';') { /* GIF terminator */
 252             return;
 253         }
 254
 255         if (c == '!') { /* Extension */
 256             if (!ReadOK(fd, &c, 1)) {
 257                 Fprintf(stderr,
 258                         "EOF / read error on extension function code\n");
 259                 exit(EXIT_FAILURE);
 260             }
 261             DoExtension(fd, (int) c);
 262             continue;
 263         }
 264
 265         if (c != ',') { /* Not a valid start character */
 266             Fprintf(stderr, "bogus character 0x%02x, ignoring\n", (int) c);
 267             continue;
 268         }
 269
 270         if (!ReadOK(fd, buf, 9)) {
 271             Fprintf(stderr, "couldn't read left/top/width/height\n");
 272             exit(EXIT_FAILURE);
 273         }
 274
 275         if (BitSet(buf[8], LOCALCOLORMAP)) {
 276             /* replace global color map with local */
 277             GifScreen.Colors = 1 << ((buf[8] & 0x07) + 1);
 278             if (!ReadColorMap(fd, GifScreen.Colors)) {
 279                 Fprintf(stderr, "error reading local colormap\n");
 280                 exit(EXIT_FAILURE);
 281             }
 282         }
 283         if (GifScreen.Width != LM_to_uint(buf[4], buf[5])) {
 284             Fprintf(stderr, "warning: widths don't match\n");
 285             GifScreen.Width = LM_to_uint(buf[4], buf[5]);
 286         }
 287         if (GifScreen.Height != LM_to_uint(buf[6], buf[7])) {
 288             Fprintf(stderr, "warning: heights don't match\n");
 289             GifScreen.Height = LM_to_uint(buf[6], buf[7]);
 290         }
 291         GifScreen.Interlace = BitSet(buf[8], INTERLACE);
 292         return;
 293     }
 294 }
 295
 296 static int
 297 GetCode(fd, code_size, flag)
 298 FILE *fd;
 299 int code_size;
 300 int flag;
 301 {
 302     static unsigned char buf[280];
 303     static int curbit, lastbit, done, last_byte;
 304     int i, j, ret;
 305     unsigned char count;
 306
 307     if (flag) {
 308         curbit = 0;
 309         lastbit = 0;
 310         done = FALSE;
 311         return 0;
 312     }
 313
 314     if ((curbit + code_size) >= lastbit) {
 315         if (done) {
 316             if (curbit >= lastbit)
 317                 Fprintf(stderr, "ran off the end of my bits\n");
 318             return -1;
 319         }
 320         buf[0] = buf[last_byte - 2];
 321         buf[1] = buf[last_byte - 1];
 322
 323         if ((count = GetDataBlock(fd, &buf[2])) == 0)
 324             done = TRUE;
 325
 326         last_byte = 2 + count;
 327         curbit = (curbit - lastbit) + 16;
 328         lastbit = (2 + count) * 8;
 329     }
 330
 331     ret = 0;
 332     for (i = curbit, j = 0; j < code_size; ++i, ++j)
 333         ret |= ((buf[i / 8] & (1 << (i % 8))) != 0) << j;
 334
 335     curbit += code_size;
 336
 337     return ret;
 338 }
 339
 340 static int
 341 LWZReadByte(fd, flag, input_code_size)
 342 FILE *fd;
 343 int flag;
 344 int input_code_size;
 345 {
 346     static int fresh = FALSE;
 347     int code, incode;
 348     static int code_size, set_code_size;
 349     static int max_code, max_code_size;
 350     static int firstcode, oldcode;
 351     static int clear_code, end_code;
 352     static int table[2][(1 << MAX_LWZ_BITS)];
 353     static int stack[(1 << (MAX_LWZ_BITS)) * 2], *sp;
 354     register int i;
 355
 356     if (flag) {
 357         set_code_size = input_code_size;
 358         code_size = set_code_size + 1;
 359         clear_code = 1 << set_code_size;
 360         end_code = clear_code + 1;
 361         max_code_size = 2 * clear_code;
 362         max_code = clear_code + 2;
 363
 364         (void) GetCode(fd, 0, TRUE);
 365
 366         fresh = TRUE;
 367
 368         for (i = 0; i < clear_code; ++i) {
 369             table[0][i] = 0;
 370             table[1][i] = i;
 371         }
 372         for (; i < (1 << MAX_LWZ_BITS); ++i)
 373             table[0][i] = table[1][0] = 0;
 374
 375         sp = stack;
 376
 377         return 0;
 378     } else if (fresh) {
 379         fresh = FALSE;
 380         do {
 381             firstcode = oldcode = GetCode(fd, code_size, FALSE);
 382         } while (firstcode == clear_code);
 383         return firstcode;
 384     }
 385
 386     if (sp > stack)
 387         return *--sp;
 388
 389     while ((code = GetCode(fd, code_size, FALSE)) >= 0) {
 390         if (code == clear_code) {
 391             for (i = 0; i < clear_code; ++i) {
 392                 table[0][i] = 0;
 393                 table[1][i] = i;
 394             }
 395             for (; i < (1 << MAX_LWZ_BITS); ++i)
 396                 table[0][i] = table[1][i] = 0;
 397             code_size = set_code_size + 1;
 398             max_code_size = 2 * clear_code;
 399             max_code = clear_code + 2;
 400             sp = stack;
 401             firstcode = oldcode = GetCode(fd, code_size, FALSE);
 402             return firstcode;
 403         } else if (code == end_code) {
 404             int count;
 405             unsigned char buf[260];
 406
 407             if (ZeroDataBlock)
 408                 return -2;
 409
 410             while ((count = GetDataBlock(fd, buf)) > 0)
 411                 ;
 412
 413             if (count != 0)
 414                 Fprintf(stderr,
 415                         "missing EOD in data stream (common occurrence)\n");
 416             return -2;
 417         }
 418
 419         incode = code;
 420
 421         if (code >= max_code) {
 422             *sp++ = firstcode;
 423             code = oldcode;
 424         }
 425
 426         while (code >= clear_code) {
 427             *sp++ = table[1][code];
 428             if (code == table[0][code]) {
 429                 Fprintf(stderr, "circular table entry BIG ERROR\n");
 430                 exit(EXIT_FAILURE);
 431             }
 432             code = table[0][code];
 433         }
 434
 435         *sp++ = firstcode = table[1][code];
 436
 437         if ((code = max_code) < (1 << MAX_LWZ_BITS)) {
 438             table[0][code] = oldcode;
 439             table[1][code] = firstcode;
 440             ++max_code;
 441             if ((max_code >= max_code_size)
 442                 && (max_code_size < (1 << MAX_LWZ_BITS))) {
 443                 max_code_size *= 2;
 444                 ++code_size;
 445             }
 446         }
 447
 448         oldcode = incode;
 449
 450         if (sp > stack)
 451             return *--sp;
 452     }
 453     return code;
 454 }
 455
 456 static void
 457 ReadInterleavedImage(fd, len, height)
 458 FILE *fd;
 459 int len, height;
 460 {
 461     int v;
 462     int xpos = 0, ypos = 0, pass = 0;
 463
 464     while ((v = LWZReadByte(fd, FALSE, (int) input_code_size)) >= 0) {
 465         PPM_ASSIGN(image[ypos][xpos], ColorMap[CM_RED][v],
 466                    ColorMap[CM_GREEN][v], ColorMap[CM_BLUE][v]);
 467
 468         ++xpos;
 469         if (xpos == len) {
 470             xpos = 0;
 471             switch (pass) {
 472             case 0:
 473             case 1:
 474                 ypos += 8;
 475                 break;
 476             case 2:
 477                 ypos += 4;
 478                 break;
 479             case 3:
 480                 ypos += 2;
 481                 break;
 482             }
 483
 484             if (ypos >= height) {
 485                 ++pass;
 486                 switch (pass) {
 487                 case 1:
 488                     ypos = 4;
 489                     break;
 490                 case 2:
 491                     ypos = 2;
 492                     break;
 493                 case 3:
 494                     ypos = 1;
 495                     break;
 496                 default:
 497                     goto fini;
 498                 }
 499             }
 500         }
 501         if (ypos >= height)
 502             break;
 503     }
 504
 505 fini:
 506     if (LWZReadByte(fd, FALSE, (int) input_code_size) >= 0)
 507         Fprintf(stderr, "too much input data, ignoring extra...\n");
 508 }
 509
 510 static void
 511 ReadTileStrip(fd, len)
 512 FILE *fd;
 513 int len;
 514 {
 515     int v;
 516     int xpos = 0, ypos = 0;
 517
 518     while ((v = LWZReadByte(fd, FALSE, (int) input_code_size)) >= 0) {
 519         PPM_ASSIGN(image[ypos][xpos], ColorMap[CM_RED][v],
 520                    ColorMap[CM_GREEN][v], ColorMap[CM_BLUE][v]);
 521
 522         ++xpos;
 523         if (xpos == len) {
 524             xpos = 0;
 525             ++ypos;
 526         }
 527         if (ypos >= TILE_Y)
 528             break;
 529     }
 530 }
 531
 532 boolean
 533 fopen_gif_file(filename, type)
 534 const char *filename;
 535 const char *type;
 536 {
 537     int i;
 538
 539     if (strcmp(type, RDBMODE)) {
 540         Fprintf(stderr, "using reading routine for non-reading?\n");
 541         return FALSE;
 542     }
 543     gif_file = fopen(filename, type);
 544     if (gif_file == (FILE *) 0) {
 545         Fprintf(stderr, "cannot open gif file %s\n", filename);
 546         return FALSE;
 547     }
 548
 549     read_header(gif_file);
 550     if (GifScreen.Width % TILE_X) {
 551         Fprintf(stderr, "error: width %d not divisible by %d\n",
 552                 GifScreen.Width, TILE_X);
 553         exit(EXIT_FAILURE);
 554     }
 555     tiles_across = GifScreen.Width / TILE_X;
 556     curr_tiles_across = 0;
 557     if (GifScreen.Height % TILE_Y) {
 558         Fprintf(stderr, "error: height %d not divisible by %d\n",
 559                 GifScreen.Height, TILE_Y);
 560         /* exit(EXIT_FAILURE) */;
 561     }
 562     tiles_down = GifScreen.Height / TILE_Y;
 563     curr_tiles_down = 0;
 564
 565     if (GifScreen.Interlace) {
 566         /* sigh -- hope this doesn't happen on micros */
 567         image = (pixel **) alloc(GifScreen.Height * sizeof(pixel *));
 568         for (i = 0; i < GifScreen.Height; i++) {
 569             image[i] = (pixel *) alloc(GifScreen.Width * sizeof(pixel));
 570         }
 571     } else {
 572         image = (pixel **) alloc(TILE_Y * sizeof(pixel *));
 573         for (i = 0; i < TILE_Y; i++) {
 574             image[i] = (pixel *) alloc(GifScreen.Width * sizeof(pixel));
 575         }
 576     }
 577
 578     /*
 579     **  Initialize the Compression routines
 580     */
 581     if (!ReadOK(gif_file, &input_code_size, 1)) {
 582         Fprintf(stderr, "EOF / read error on image data\n");
 583         exit(EXIT_FAILURE);
 584     }
 585
 586     if (LWZReadByte(gif_file, TRUE, (int) input_code_size) < 0) {
 587         Fprintf(stderr, "error reading image\n");
 588         exit(EXIT_FAILURE);
 589     }
 590
 591     /* read first section */
 592     if (GifScreen.Interlace) {
 593         ReadInterleavedImage(gif_file, GifScreen.Width, GifScreen.Height);
 594     } else {
 595         ReadTileStrip(gif_file, GifScreen.Width);
 596     }
 597     return TRUE;
 598 }
 599
 600 /* Read a tile.  Returns FALSE when there are no more tiles */
 601 boolean
 602 read_gif_tile(pixels)
 603 pixel (*pixels)[TILE_X];
 604 {
 605     int i, j;
 606
 607     if (curr_tiles_down >= tiles_down)
 608         return FALSE;
 609     if (curr_tiles_across == tiles_across) {
 610         curr_tiles_across = 0;
 611         curr_tiles_down++;
 612         if (curr_tiles_down >= tiles_down)
 613             return FALSE;
 614         if (!GifScreen.Interlace)
 615             ReadTileStrip(gif_file, GifScreen.Width);
 616     }
 617     if (GifScreen.Interlace) {
 618         for (j = 0; j < TILE_Y; j++) {
 619             for (i = 0; i < TILE_X; i++) {
 620                 pixels[j][i] = image[curr_tiles_down * TILE_Y
 621                                      + j][curr_tiles_across * TILE_X + i];
 622             }
 623         }
 624     } else {
 625         for (j = 0; j < TILE_Y; j++) {
 626             for (i = 0; i < TILE_X; i++) {
 627                 pixels[j][i] = image[j][curr_tiles_across * TILE_X + i];
 628             }
 629         }
 630     }
 631     curr_tiles_across++;
 632
 633     /* check for "filler" tile */
 634     for (j = 0; j < TILE_Y; j++) {
 635         for (i = 0; i < TILE_X && i < 4; i += 2) {
 636             if (pixels[j][i].r != ColorMap[CM_RED][0]
 637                 || pixels[j][i].g != ColorMap[CM_GREEN][0]
 638                 || pixels[j][i].b != ColorMap[CM_BLUE][0]
 639                 || pixels[j][i + 1].r != ColorMap[CM_RED][1]
 640                 || pixels[j][i + 1].g != ColorMap[CM_GREEN][1]
 641                 || pixels[j][i + 1].b != ColorMap[CM_BLUE][1])
 642                 return TRUE;
 643         }
 644     }
 645     return FALSE;
 646 }
 647
 648 int
 649 fclose_gif_file()
 650 {
 651     int i;
 652
 653     if (GifScreen.Interlace) {
 654         for (i = 0; i < GifScreen.Height; i++) {
 655             free((genericptr_t) image[i]);
 656         }
 657         free((genericptr_t) image);
 658     } else {
 659         for (i = 0; i < TILE_Y; i++) {
 660             free((genericptr_t) image[i]);
 661         }
 662         free((genericptr_t) image);
 663     }
 664     return (fclose(gif_file));
 665 }
 666
 667 #ifndef AMIGA
 668 static char *std_args[] = { "tilemap", /* dummy argv[0] */
 669                             "monsters.gif", "monsters.txt", "objects.gif",
 670                             "objects.txt",  "other.gif",    "other.txt" };
 671
 672 int
 673 main(argc, argv)
 674 int argc;
 675 char *argv[];
 676 {
 677     pixel pixels[TILE_Y][TILE_X];
 678
 679     if (argc == 1) {
 680         argc = SIZE(std_args);
 681         argv = std_args;
 682     } else if (argc != 3) {
 683         Fprintf(stderr, "usage: gif2txt giffile txtfile\n");
 684         exit(EXIT_FAILURE);
 685     }
 686
 687     while (argc > 1) {
 688         if (!fopen_gif_file(argv[1], RDBMODE))
 689             exit(EXIT_FAILURE);
 690
 691         init_colormap();
 692
 693         if (!fopen_text_file(argv[2], WRTMODE)) {
 694             (void) fclose_gif_file();
 695             exit(EXIT_FAILURE);
 696         }
 697
 698         while (read_gif_tile(pixels))
 699             (void) write_text_tile(pixels);
 700
 701         (void) fclose_gif_file();
 702         (void) fclose_text_file();
 703
 704         argc -= 2;
 705         argv += 2;
 706     }
 707     exit(EXIT_SUCCESS);
 708     /*NOTREACHED*/
 709     return 0;
 710 }
 711 #endif