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| 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 */ |
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