workbench/libs/jpeg/rdtarga.c

   1 /*
   2  * rdtarga.c
   3  *
   4  * Copyright (C) 1991-1996, Thomas G. Lane.
   5  * This file is part of the Independent JPEG Group's software.
   6  * For conditions of distribution and use, see the accompanying README file.
   7  *
   8  * This file contains routines to read input images in Targa format.
   9  *
  10  * These routines may need modification for non-Unix environments or
  11  * specialized applications.  As they stand, they assume input from
  12  * an ordinary stdio stream.  They further assume that reading begins
  13  * at the start of the file; start_input may need work if the
  14  * user interface has already read some data (e.g., to determine that
  15  * the file is indeed Targa format).
  16  *
  17  * Based on code contributed by Lee Daniel Crocker.
  18  */
  19
  20 #include "cdjpeg.h"             /* Common decls for cjpeg/djpeg applications */
  21
  22 #ifdef TARGA_SUPPORTED
  23
  24
  25 /* Macros to deal with unsigned chars as efficiently as compiler allows */
  26
  27 #ifdef HAVE_UNSIGNED_CHAR
  28 typedef unsigned char U_CHAR;
  29 #define UCH(x)  ((int) (x))
  30 #else /* !HAVE_UNSIGNED_CHAR */
  31 #ifdef CHAR_IS_UNSIGNED
  32 typedef char U_CHAR;
  33 #define UCH(x)  ((int) (x))
  34 #else
  35 typedef char U_CHAR;
  36 #define UCH(x)  ((int) (x) & 0xFF)
  37 #endif
  38 #endif /* HAVE_UNSIGNED_CHAR */
  39
  40
  41 #define ReadOK(file,buffer,len) (JFREAD(file,buffer,len) == ((size_t) (len)))
  42
  43
  44 /* Private version of data source object */
  45
  46 typedef struct _tga_source_struct * tga_source_ptr;
  47
  48 typedef struct _tga_source_struct {
  49   struct cjpeg_source_struct pub; /* public fields */
  50
  51   j_compress_ptr cinfo;         /* back link saves passing separate parm */
  52
  53   JSAMPARRAY colormap;          /* Targa colormap (converted to my format) */
  54
  55   jvirt_sarray_ptr whole_image; /* Needed if funny input row order */
  56   JDIMENSION current_row;       /* Current logical row number to read */
  57
  58   /* Pointer to routine to extract next Targa pixel from input file */
  59   JMETHOD(void, read_pixel, (tga_source_ptr sinfo));
  60
  61   /* Result of read_pixel is delivered here: */
  62   U_CHAR tga_pixel[4];
  63
  64   int pixel_size;               /* Bytes per Targa pixel (1 to 4) */
  65
  66   /* State info for reading RLE-coded pixels; both counts must be init to 0 */
  67   int block_count;              /* # of pixels remaining in RLE block */
  68   int dup_pixel_count;          /* # of times to duplicate previous pixel */
  69
  70   /* This saves the correct pixel-row-expansion method for preload_image */
  71   JMETHOD(JDIMENSION, get_pixel_rows, (j_compress_ptr cinfo,
  72                                        cjpeg_source_ptr sinfo));
  73 } tga_source_struct;
  74
  75
  76 /* For expanding 5-bit pixel values to 8-bit with best rounding */
  77
  78 static const UINT8 c5to8bits[32] = {
  79     0,   8,  16,  25,  33,  41,  49,  58,
  80    66,  74,  82,  90,  99, 107, 115, 123,
  81   132, 140, 148, 156, 165, 173, 181, 189,
  82   197, 206, 214, 222, 230, 239, 247, 255
  83 };
  84
  85
  86
  87 LOCAL(int)
  88 read_byte (tga_source_ptr sinfo)
  89 /* Read next byte from Targa file */
  90 {
  91   register FILE *infile = sinfo->pub.input_file;
  92   register int c;
  93
  94   if ((c = getc(infile)) == EOF)
  95     ERREXIT(sinfo->cinfo, JERR_INPUT_EOF);
  96   return c;
  97 }
  98
  99
 100 LOCAL(void)
 101 read_colormap (tga_source_ptr sinfo, int cmaplen, int mapentrysize)
 102 /* Read the colormap from a Targa file */
 103 {
 104   int i;
 105
 106   /* Presently only handles 24-bit BGR format */
 107   if (mapentrysize != 24)
 108     ERREXIT(sinfo->cinfo, JERR_TGA_BADCMAP);
 109
 110   for (i = 0; i < cmaplen; i++) {
 111     sinfo->colormap[2][i] = (JSAMPLE) read_byte(sinfo);
 112     sinfo->colormap[1][i] = (JSAMPLE) read_byte(sinfo);
 113     sinfo->colormap[0][i] = (JSAMPLE) read_byte(sinfo);
 114   }
 115 }
 116
 117
 118 /*
 119  * read_pixel methods: get a single pixel from Targa file into tga_pixel[]
 120  */
 121
 122 METHODDEF(void)
 123 read_non_rle_pixel (tga_source_ptr sinfo)
 124 /* Read one Targa pixel from the input file; no RLE expansion */
 125 {
 126   register FILE *infile = sinfo->pub.input_file;
 127   register int i;
 128
 129   for (i = 0; i < sinfo->pixel_size; i++) {
 130     sinfo->tga_pixel[i] = (U_CHAR) getc(infile);
 131   }
 132 }
 133
 134
 135 METHODDEF(void)
 136 read_rle_pixel (tga_source_ptr sinfo)
 137 /* Read one Targa pixel from the input file, expanding RLE data as needed */
 138 {
 139   register FILE *infile = sinfo->pub.input_file;
 140   register int i;
 141
 142   /* Duplicate previously read pixel? */
 143   if (sinfo->dup_pixel_count > 0) {
 144     sinfo->dup_pixel_count--;
 145     return;
 146   }
 147
 148   /* Time to read RLE block header? */
 149   if (--sinfo->block_count < 0) { /* decrement pixels remaining in block */
 150     i = read_byte(sinfo);
 151     if (i & 0x80) {             /* Start of duplicate-pixel block? */
 152       sinfo->dup_pixel_count = i & 0x7F; /* number of dups after this one */
 153       sinfo->block_count = 0;   /* then read new block header */
 154     } else {
 155       sinfo->block_count = i & 0x7F; /* number of pixels after this one */
 156     }
 157   }
 158
 159   /* Read next pixel */
 160   for (i = 0; i < sinfo->pixel_size; i++) {
 161     sinfo->tga_pixel[i] = (U_CHAR) getc(infile);
 162   }
 163 }
 164
 165
 166 /*
 167  * Read one row of pixels.
 168  *
 169  * We provide several different versions depending on input file format.
 170  */
 171
 172
 173 METHODDEF(JDIMENSION)
 174 get_8bit_gray_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
 175 /* This version is for reading 8-bit grayscale pixels */
 176 {
 177   tga_source_ptr source = (tga_source_ptr) sinfo;
 178   register JSAMPROW ptr;
 179   register JDIMENSION col;
 180
 181   ptr = source->pub.buffer[0];
 182   for (col = cinfo->image_width; col > 0; col--) {
 183     (*source->read_pixel) (source); /* Load next pixel into tga_pixel */
 184     *ptr++ = (JSAMPLE) UCH(source->tga_pixel[0]);
 185   }
 186   return 1;
 187 }
 188
 189 METHODDEF(JDIMENSION)
 190 get_8bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
 191 /* This version is for reading 8-bit colormap indexes */
 192 {
 193   tga_source_ptr source = (tga_source_ptr) sinfo;
 194   register int t;
 195   register JSAMPROW ptr;
 196   register JDIMENSION col;
 197   register JSAMPARRAY colormap = source->colormap;
 198
 199   ptr = source->pub.buffer[0];
 200   for (col = cinfo->image_width; col > 0; col--) {
 201     (*source->read_pixel) (source); /* Load next pixel into tga_pixel */
 202     t = UCH(source->tga_pixel[0]);
 203     *ptr++ = colormap[0][t];
 204     *ptr++ = colormap[1][t];
 205     *ptr++ = colormap[2][t];
 206   }
 207   return 1;
 208 }
 209
 210 METHODDEF(JDIMENSION)
 211 get_16bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
 212 /* This version is for reading 16-bit pixels */
 213 {
 214   tga_source_ptr source = (tga_source_ptr) sinfo;
 215   register int t;
 216   register JSAMPROW ptr;
 217   register JDIMENSION col;
 218
 219   ptr = source->pub.buffer[0];
 220   for (col = cinfo->image_width; col > 0; col--) {
 221     (*source->read_pixel) (source); /* Load next pixel into tga_pixel */
 222     t = UCH(source->tga_pixel[0]);
 223     t += UCH(source->tga_pixel[1]) << 8;
 224     /* We expand 5 bit data to 8 bit sample width.
 225      * The format of the 16-bit (LSB first) input word is
 226      *     xRRRRRGGGGGBBBBB
 227      */
 228     ptr[2] = (JSAMPLE) c5to8bits[t & 0x1F];
 229     t >>= 5;
 230     ptr[1] = (JSAMPLE) c5to8bits[t & 0x1F];
 231     t >>= 5;
 232     ptr[0] = (JSAMPLE) c5to8bits[t & 0x1F];
 233     ptr += 3;
 234   }
 235   return 1;
 236 }
 237
 238 METHODDEF(JDIMENSION)
 239 get_24bit_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
 240 /* This version is for reading 24-bit pixels */
 241 {
 242   tga_source_ptr source = (tga_source_ptr) sinfo;
 243   register JSAMPROW ptr;
 244   register JDIMENSION col;
 245
 246   ptr = source->pub.buffer[0];
 247   for (col = cinfo->image_width; col > 0; col--) {
 248     (*source->read_pixel) (source); /* Load next pixel into tga_pixel */
 249     *ptr++ = (JSAMPLE) UCH(source->tga_pixel[2]); /* change BGR to RGB order */
 250     *ptr++ = (JSAMPLE) UCH(source->tga_pixel[1]);
 251     *ptr++ = (JSAMPLE) UCH(source->tga_pixel[0]);
 252   }
 253   return 1;
 254 }
 255
 256 /*
 257  * Targa also defines a 32-bit pixel format with order B,G,R,A.
 258  * We presently ignore the attribute byte, so the code for reading
 259  * these pixels is identical to the 24-bit routine above.
 260  * This works because the actual pixel length is only known to read_pixel.
 261  */
 262
 263 #define get_32bit_row  get_24bit_row
 264
 265
 266 /*
 267  * This method is for re-reading the input data in standard top-down
 268  * row order.  The entire image has already been read into whole_image
 269  * with proper conversion of pixel format, but it's in a funny row order.
 270  */
 271
 272 METHODDEF(JDIMENSION)
 273 get_memory_row (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
 274 {
 275   tga_source_ptr source = (tga_source_ptr) sinfo;
 276   JDIMENSION source_row;
 277
 278   /* Compute row of source that maps to current_row of normal order */
 279   /* For now, assume image is bottom-up and not interlaced. */
 280   /* NEEDS WORK to support interlaced images! */
 281   source_row = cinfo->image_height - source->current_row - 1;
 282
 283   /* Fetch that row from virtual array */
 284   source->pub.buffer = (*cinfo->mem->access_virt_sarray)
 285     ((j_common_ptr) cinfo, source->whole_image,
 286      source_row, (JDIMENSION) 1, FALSE);
 287
 288   source->current_row++;
 289   return 1;
 290 }
 291
 292
 293 /*
 294  * This method loads the image into whole_image during the first call on
 295  * get_pixel_rows.  The get_pixel_rows pointer is then adjusted to call
 296  * get_memory_row on subsequent calls.
 297  */
 298
 299 METHODDEF(JDIMENSION)
 300 preload_image (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
 301 {
 302   tga_source_ptr source = (tga_source_ptr) sinfo;
 303   JDIMENSION row;
 304   cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;
 305
 306   /* Read the data into a virtual array in input-file row order. */
 307   for (row = 0; row < cinfo->image_height; row++) {
 308     if (progress != NULL) {
 309       progress->pub.pass_counter = (long) row;
 310       progress->pub.pass_limit = (long) cinfo->image_height;
 311       (*progress->pub.progress_monitor) ((j_common_ptr) cinfo);
 312     }
 313     source->pub.buffer = (*cinfo->mem->access_virt_sarray)
 314       ((j_common_ptr) cinfo, source->whole_image, row, (JDIMENSION) 1, TRUE);
 315     (*source->get_pixel_rows) (cinfo, sinfo);
 316   }
 317   if (progress != NULL)
 318     progress->completed_extra_passes++;
 319
 320   /* Set up to read from the virtual array in unscrambled order */
 321   source->pub.get_pixel_rows = get_memory_row;
 322   source->current_row = 0;
 323   /* And read the first row */
 324   return get_memory_row(cinfo, sinfo);
 325 }
 326
 327
 328 /*
 329  * Read the file header; return image size and component count.
 330  */
 331
 332 METHODDEF(void)
 333 start_input_tga (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
 334 {
 335   tga_source_ptr source = (tga_source_ptr) sinfo;
 336   U_CHAR targaheader[18];
 337   int idlen, cmaptype, subtype, flags, interlace_type, components;
 338   unsigned int width, height, maplen;
 339   boolean is_bottom_up;
 340
 341 #define GET_2B(offset)  ((unsigned int) UCH(targaheader[offset]) + \
 342                          (((unsigned int) UCH(targaheader[offset+1])) << 8))
 343
 344   if (! ReadOK(source->pub.input_file, targaheader, 18))
 345     ERREXIT(cinfo, JERR_INPUT_EOF);
 346
 347   /* Pretend "15-bit" pixels are 16-bit --- we ignore attribute bit anyway */
 348   if (targaheader[16] == 15)
 349     targaheader[16] = 16;
 350
 351   idlen = UCH(targaheader[0]);
 352   cmaptype = UCH(targaheader[1]);
 353   subtype = UCH(targaheader[2]);
 354   maplen = GET_2B(5);
 355   width = GET_2B(12);
 356   height = GET_2B(14);
 357   source->pixel_size = UCH(targaheader[16]) >> 3;
 358   flags = UCH(targaheader[17]); /* Image Descriptor byte */
 359
 360   is_bottom_up = ((flags & 0x20) == 0); /* bit 5 set => top-down */
 361   interlace_type = flags >> 6;  /* bits 6/7 are interlace code */
 362
 363   if (cmaptype > 1 ||           /* cmaptype must be 0 or 1 */
 364       source->pixel_size < 1 || source->pixel_size > 4 ||
 365       (UCH(targaheader[16]) & 7) != 0 || /* bits/pixel must be multiple of 8 */
 366       interlace_type != 0)      /* currently don't allow interlaced image */
 367     ERREXIT(cinfo, JERR_TGA_BADPARMS);
 368
 369   if (subtype > 8) {
 370     /* It's an RLE-coded file */
 371     source->read_pixel = read_rle_pixel;
 372     source->block_count = source->dup_pixel_count = 0;
 373     subtype -= 8;
 374   } else {
 375     /* Non-RLE file */
 376     source->read_pixel = read_non_rle_pixel;
 377   }
 378
 379   /* Now should have subtype 1, 2, or 3 */
 380   components = 3;               /* until proven different */
 381   cinfo->in_color_space = JCS_RGB;
 382
 383   switch (subtype) {
 384   case 1:                       /* Colormapped image */
 385     if (source->pixel_size == 1 && cmaptype == 1)
 386       source->get_pixel_rows = get_8bit_row;
 387     else
 388       ERREXIT(cinfo, JERR_TGA_BADPARMS);
 389     TRACEMS2(cinfo, 1, JTRC_TGA_MAPPED, width, height);
 390     break;
 391   case 2:                       /* RGB image */
 392     switch (source->pixel_size) {
 393     case 2:
 394       source->get_pixel_rows = get_16bit_row;
 395       break;
 396     case 3:
 397       source->get_pixel_rows = get_24bit_row;
 398       break;
 399     case 4:
 400       source->get_pixel_rows = get_32bit_row;
 401       break;
 402     default:
 403       ERREXIT(cinfo, JERR_TGA_BADPARMS);
 404       break;
 405     }
 406     TRACEMS2(cinfo, 1, JTRC_TGA, width, height);
 407     break;
 408   case 3:                       /* Grayscale image */
 409     components = 1;
 410     cinfo->in_color_space = JCS_GRAYSCALE;
 411     if (source->pixel_size == 1)
 412       source->get_pixel_rows = get_8bit_gray_row;
 413     else
 414       ERREXIT(cinfo, JERR_TGA_BADPARMS);
 415     TRACEMS2(cinfo, 1, JTRC_TGA_GRAY, width, height);
 416     break;
 417   default:
 418     ERREXIT(cinfo, JERR_TGA_BADPARMS);
 419     break;
 420   }
 421
 422   if (is_bottom_up) {
 423     /* Create a virtual array to buffer the upside-down image. */
 424     source->whole_image = (*cinfo->mem->request_virt_sarray)
 425       ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
 426        (JDIMENSION) width * components, (JDIMENSION) height, (JDIMENSION) 1);
 427     if (cinfo->progress != NULL) {
 428       cd_progress_ptr progress = (cd_progress_ptr) cinfo->progress;
 429       progress->total_extra_passes++; /* count file input as separate pass */
 430     }
 431     /* source->pub.buffer will point to the virtual array. */
 432     source->pub.buffer_height = 1; /* in case anyone looks at it */
 433     source->pub.get_pixel_rows = preload_image;
 434   } else {
 435     /* Don't need a virtual array, but do need a one-row input buffer. */
 436     source->whole_image = NULL;
 437     source->pub.buffer = (*cinfo->mem->alloc_sarray)
 438       ((j_common_ptr) cinfo, JPOOL_IMAGE,
 439        (JDIMENSION) width * components, (JDIMENSION) 1);
 440     source->pub.buffer_height = 1;
 441     source->pub.get_pixel_rows = source->get_pixel_rows;
 442   }
 443
 444   while (idlen--)               /* Throw away ID field */
 445     (void) read_byte(source);
 446
 447   if (maplen > 0) {
 448     if (maplen > 256 || GET_2B(3) != 0)
 449       ERREXIT(cinfo, JERR_TGA_BADCMAP);
 450     /* Allocate space to store the colormap */
 451     source->colormap = (*cinfo->mem->alloc_sarray)
 452       ((j_common_ptr) cinfo, JPOOL_IMAGE, (JDIMENSION) maplen, (JDIMENSION) 3);
 453     /* and read it from the file */
 454     read_colormap(source, (int) maplen, UCH(targaheader[7]));
 455   } else {
 456     if (cmaptype)               /* but you promised a cmap! */
 457       ERREXIT(cinfo, JERR_TGA_BADPARMS);
 458     source->colormap = NULL;
 459   }
 460
 461   cinfo->input_components = components;
 462   cinfo->data_precision = 8;
 463   cinfo->image_width = width;
 464   cinfo->image_height = height;
 465 }
 466
 467
 468 /*
 469  * Finish up at the end of the file.
 470  */
 471
 472 METHODDEF(void)
 473 finish_input_tga (j_compress_ptr cinfo, cjpeg_source_ptr sinfo)
 474 {
 475   /* no work */
 476 }
 477
 478
 479 /*
 480  * The module selection routine for Targa format input.
 481  */
 482
 483 GLOBAL(cjpeg_source_ptr)
 484 jinit_read_targa (j_compress_ptr cinfo)
 485 {
 486   tga_source_ptr source;
 487
 488   /* Create module interface object */
 489   source = (tga_source_ptr)
 490       (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
 491                                   SIZEOF(tga_source_struct));
 492   source->cinfo = cinfo;        /* make back link for subroutines */
 493   /* Fill in method ptrs, except get_pixel_rows which start_input sets */
 494   source->pub.start_input = start_input_tga;
 495   source->pub.finish_input = finish_input_tga;
 496
 497   return (cjpeg_source_ptr) source;
 498 }
 499
 500 #endif /* TARGA_SUPPORTED */