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