1 /* 2 * jdmaster.c 3 * 4 * This file was part of the Independent JPEG Group's software: 5 * Copyright (C) 1991-1997, Thomas G. Lane. 6 * Modified 2002-2009 by Guido Vollbeding. 7 * libjpeg-turbo Modifications: 8 * Copyright (C) 2009-2011, D. R. Commander. 9 * For conditions of distribution and use, see the accompanying README file. 10 * 11 * This file contains master control logic for the JPEG decompressor. 12 * These routines are concerned with selecting the modules to be executed 13 * and with determining the number of passes and the work to be done in each 14 * pass. 15 */ 16 17 #define JPEG_INTERNALS 18 #include "jinclude.h" 19 #include "jpeglib.h" 20 #include "jpegcomp.h" 21 22 23 /* Private state */ 24 25 typedef struct { 26 struct jpeg_decomp_master pub; /* public fields */ 27 28 int pass_number; /* # of passes completed */ 29 30 boolean using_merged_upsample; /* TRUE if using merged upsample/cconvert */ 31 32 /* Saved references to initialized quantizer modules, 33 * in case we need to switch modes. 34 */ 35 struct jpeg_color_quantizer * quantizer_1pass; 36 struct jpeg_color_quantizer * quantizer_2pass; 37 } my_decomp_master; 38 39 typedef my_decomp_master * my_master_ptr; 40 41 42 /* 43 * Determine whether merged upsample/color conversion should be used. 44 * CRUCIAL: this must match the actual capabilities of jdmerge.c! 45 */ 46 47 LOCAL(boolean) 48 use_merged_upsample (j_decompress_ptr cinfo) 49 { 50 #ifdef UPSAMPLE_MERGING_SUPPORTED 51 /* Merging is the equivalent of plain box-filter upsampling */ 52 if (cinfo->do_fancy_upsampling || cinfo->CCIR601_sampling) 53 return FALSE; 54 /* jdmerge.c only supports YCC=>RGB color conversion */ 55 if (cinfo->jpeg_color_space != JCS_YCbCr || cinfo->num_components != 3 || 56 (cinfo->out_color_space != JCS_RGB && 57 cinfo->out_color_space != JCS_EXT_RGB && 58 cinfo->out_color_space != JCS_EXT_RGBX && 59 cinfo->out_color_space != JCS_EXT_BGR && 60 cinfo->out_color_space != JCS_EXT_BGRX && 61 cinfo->out_color_space != JCS_EXT_XBGR && 62 cinfo->out_color_space != JCS_EXT_XRGB && 63 cinfo->out_color_space != JCS_EXT_RGBA && 64 cinfo->out_color_space != JCS_EXT_BGRA && 65 cinfo->out_color_space != JCS_EXT_ABGR && 66 cinfo->out_color_space != JCS_EXT_ARGB) || 67 cinfo->out_color_components != rgb_pixelsize[cinfo->out_color_space]) 68 return FALSE; 69 /* and it only handles 2h1v or 2h2v sampling ratios */ 70 if (cinfo->comp_info[0].h_samp_factor != 2 || 71 cinfo->comp_info[1].h_samp_factor != 1 || 72 cinfo->comp_info[2].h_samp_factor != 1 || 73 cinfo->comp_info[0].v_samp_factor > 2 || 74 cinfo->comp_info[1].v_samp_factor != 1 || 75 cinfo->comp_info[2].v_samp_factor != 1) 76 return FALSE; 77 /* furthermore, it doesn't work if we've scaled the IDCTs differently */ 78 if (cinfo->comp_info[0]._DCT_scaled_size != cinfo->_min_DCT_scaled_size || 79 cinfo->comp_info[1]._DCT_scaled_size != cinfo->_min_DCT_scaled_size || 80 cinfo->comp_info[2]._DCT_scaled_size != cinfo->_min_DCT_scaled_size) 81 return FALSE; 82 /* ??? also need to test for upsample-time rescaling, when & if supported */ 83 return TRUE; /* by golly, it'll work... */ 84 #else 85 return FALSE; 86 #endif 87 } 88 89 90 /* 91 * Compute output image dimensions and related values. 92 * NOTE: this is exported for possible use by application. 93 * Hence it mustn't do anything that can't be done twice. 94 */ 95 96 #if JPEG_LIB_VERSION >= 80 97 GLOBAL(void) 98 #else 99 LOCAL(void) 100 #endif 101 jpeg_core_output_dimensions (j_decompress_ptr cinfo) 102 /* Do computations that are needed before master selection phase. 103 * This function is used for transcoding and full decompression. 104 */ 105 { 106 #ifdef IDCT_SCALING_SUPPORTED 107 int ci; 108 jpeg_component_info *compptr; 109 110 /* Compute actual output image dimensions and DCT scaling choices. */ 111 if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom) { 112 /* Provide 1/block_size scaling */ 113 cinfo->output_width = (JDIMENSION) 114 jdiv_round_up((long) cinfo->image_width, (long) DCTSIZE); 115 cinfo->output_height = (JDIMENSION) 116 jdiv_round_up((long) cinfo->image_height, (long) DCTSIZE); 117 cinfo->_min_DCT_h_scaled_size = 1; 118 cinfo->_min_DCT_v_scaled_size = 1; 119 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 2) { 120 /* Provide 2/block_size scaling */ 121 cinfo->output_width = (JDIMENSION) 122 jdiv_round_up((long) cinfo->image_width * 2L, (long) DCTSIZE); 123 cinfo->output_height = (JDIMENSION) 124 jdiv_round_up((long) cinfo->image_height * 2L, (long) DCTSIZE); 125 cinfo->_min_DCT_h_scaled_size = 2; 126 cinfo->_min_DCT_v_scaled_size = 2; 127 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 3) { 128 /* Provide 3/block_size scaling */ 129 cinfo->output_width = (JDIMENSION) 130 jdiv_round_up((long) cinfo->image_width * 3L, (long) DCTSIZE); 131 cinfo->output_height = (JDIMENSION) 132 jdiv_round_up((long) cinfo->image_height * 3L, (long) DCTSIZE); 133 cinfo->_min_DCT_h_scaled_size = 3; 134 cinfo->_min_DCT_v_scaled_size = 3; 135 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 4) { 136 /* Provide 4/block_size scaling */ 137 cinfo->output_width = (JDIMENSION) 138 jdiv_round_up((long) cinfo->image_width * 4L, (long) DCTSIZE); 139 cinfo->output_height = (JDIMENSION) 140 jdiv_round_up((long) cinfo->image_height * 4L, (long) DCTSIZE); 141 cinfo->_min_DCT_h_scaled_size = 4; 142 cinfo->_min_DCT_v_scaled_size = 4; 143 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 5) { 144 /* Provide 5/block_size scaling */ 145 cinfo->output_width = (JDIMENSION) 146 jdiv_round_up((long) cinfo->image_width * 5L, (long) DCTSIZE); 147 cinfo->output_height = (JDIMENSION) 148 jdiv_round_up((long) cinfo->image_height * 5L, (long) DCTSIZE); 149 cinfo->_min_DCT_h_scaled_size = 5; 150 cinfo->_min_DCT_v_scaled_size = 5; 151 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 6) { 152 /* Provide 6/block_size scaling */ 153 cinfo->output_width = (JDIMENSION) 154 jdiv_round_up((long) cinfo->image_width * 6L, (long) DCTSIZE); 155 cinfo->output_height = (JDIMENSION) 156 jdiv_round_up((long) cinfo->image_height * 6L, (long) DCTSIZE); 157 cinfo->_min_DCT_h_scaled_size = 6; 158 cinfo->_min_DCT_v_scaled_size = 6; 159 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 7) { 160 /* Provide 7/block_size scaling */ 161 cinfo->output_width = (JDIMENSION) 162 jdiv_round_up((long) cinfo->image_width * 7L, (long) DCTSIZE); 163 cinfo->output_height = (JDIMENSION) 164 jdiv_round_up((long) cinfo->image_height * 7L, (long) DCTSIZE); 165 cinfo->_min_DCT_h_scaled_size = 7; 166 cinfo->_min_DCT_v_scaled_size = 7; 167 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 8) { 168 /* Provide 8/block_size scaling */ 169 cinfo->output_width = (JDIMENSION) 170 jdiv_round_up((long) cinfo->image_width * 8L, (long) DCTSIZE); 171 cinfo->output_height = (JDIMENSION) 172 jdiv_round_up((long) cinfo->image_height * 8L, (long) DCTSIZE); 173 cinfo->_min_DCT_h_scaled_size = 8; 174 cinfo->_min_DCT_v_scaled_size = 8; 175 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 9) { 176 /* Provide 9/block_size scaling */ 177 cinfo->output_width = (JDIMENSION) 178 jdiv_round_up((long) cinfo->image_width * 9L, (long) DCTSIZE); 179 cinfo->output_height = (JDIMENSION) 180 jdiv_round_up((long) cinfo->image_height * 9L, (long) DCTSIZE); 181 cinfo->_min_DCT_h_scaled_size = 9; 182 cinfo->_min_DCT_v_scaled_size = 9; 183 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 10) { 184 /* Provide 10/block_size scaling */ 185 cinfo->output_width = (JDIMENSION) 186 jdiv_round_up((long) cinfo->image_width * 10L, (long) DCTSIZE); 187 cinfo->output_height = (JDIMENSION) 188 jdiv_round_up((long) cinfo->image_height * 10L, (long) DCTSIZE); 189 cinfo->_min_DCT_h_scaled_size = 10; 190 cinfo->_min_DCT_v_scaled_size = 10; 191 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 11) { 192 /* Provide 11/block_size scaling */ 193 cinfo->output_width = (JDIMENSION) 194 jdiv_round_up((long) cinfo->image_width * 11L, (long) DCTSIZE); 195 cinfo->output_height = (JDIMENSION) 196 jdiv_round_up((long) cinfo->image_height * 11L, (long) DCTSIZE); 197 cinfo->_min_DCT_h_scaled_size = 11; 198 cinfo->_min_DCT_v_scaled_size = 11; 199 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 12) { 200 /* Provide 12/block_size scaling */ 201 cinfo->output_width = (JDIMENSION) 202 jdiv_round_up((long) cinfo->image_width * 12L, (long) DCTSIZE); 203 cinfo->output_height = (JDIMENSION) 204 jdiv_round_up((long) cinfo->image_height * 12L, (long) DCTSIZE); 205 cinfo->_min_DCT_h_scaled_size = 12; 206 cinfo->_min_DCT_v_scaled_size = 12; 207 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 13) { 208 /* Provide 13/block_size scaling */ 209 cinfo->output_width = (JDIMENSION) 210 jdiv_round_up((long) cinfo->image_width * 13L, (long) DCTSIZE); 211 cinfo->output_height = (JDIMENSION) 212 jdiv_round_up((long) cinfo->image_height * 13L, (long) DCTSIZE); 213 cinfo->_min_DCT_h_scaled_size = 13; 214 cinfo->_min_DCT_v_scaled_size = 13; 215 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 14) { 216 /* Provide 14/block_size scaling */ 217 cinfo->output_width = (JDIMENSION) 218 jdiv_round_up((long) cinfo->image_width * 14L, (long) DCTSIZE); 219 cinfo->output_height = (JDIMENSION) 220 jdiv_round_up((long) cinfo->image_height * 14L, (long) DCTSIZE); 221 cinfo->_min_DCT_h_scaled_size = 14; 222 cinfo->_min_DCT_v_scaled_size = 14; 223 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 15) { 224 /* Provide 15/block_size scaling */ 225 cinfo->output_width = (JDIMENSION) 226 jdiv_round_up((long) cinfo->image_width * 15L, (long) DCTSIZE); 227 cinfo->output_height = (JDIMENSION) 228 jdiv_round_up((long) cinfo->image_height * 15L, (long) DCTSIZE); 229 cinfo->_min_DCT_h_scaled_size = 15; 230 cinfo->_min_DCT_v_scaled_size = 15; 231 } else { 232 /* Provide 16/block_size scaling */ 233 cinfo->output_width = (JDIMENSION) 234 jdiv_round_up((long) cinfo->image_width * 16L, (long) DCTSIZE); 235 cinfo->output_height = (JDIMENSION) 236 jdiv_round_up((long) cinfo->image_height * 16L, (long) DCTSIZE); 237 cinfo->_min_DCT_h_scaled_size = 16; 238 cinfo->_min_DCT_v_scaled_size = 16; 239 } 240 241 /* Recompute dimensions of components */ 242 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 243 ci++, compptr++) { 244 compptr->_DCT_h_scaled_size = cinfo->_min_DCT_h_scaled_size; 245 compptr->_DCT_v_scaled_size = cinfo->_min_DCT_v_scaled_size; 246 } 247 248 #else /* !IDCT_SCALING_SUPPORTED */ 249 250 /* Hardwire it to "no scaling" */ 251 cinfo->output_width = cinfo->image_width; 252 cinfo->output_height = cinfo->image_height; 253 /* jdinput.c has already initialized DCT_scaled_size, 254 * and has computed unscaled downsampled_width and downsampled_height. 255 */ 256 257 #endif /* IDCT_SCALING_SUPPORTED */ 258 } 259 260 261 /* 262 * Compute output image dimensions and related values. 263 * NOTE: this is exported for possible use by application. 264 * Hence it mustn't do anything that can't be done twice. 265 * Also note that it may be called before the master module is initialized! 266 */ 267 268 GLOBAL(void) 269 jpeg_calc_output_dimensions (j_decompress_ptr cinfo) 270 /* Do computations that are needed before master selection phase */ 271 { 272 #ifdef IDCT_SCALING_SUPPORTED 273 int ci; 274 jpeg_component_info *compptr; 275 #endif 276 277 /* Prevent application from calling me at wrong times */ 278 if (cinfo->global_state != DSTATE_READY) 279 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 280 281 /* Compute core output image dimensions and DCT scaling choices. */ 282 jpeg_core_output_dimensions(cinfo); 283 284 #ifdef IDCT_SCALING_SUPPORTED 285 286 /* In selecting the actual DCT scaling for each component, we try to 287 * scale up the chroma components via IDCT scaling rather than upsampling. 288 * This saves time if the upsampler gets to use 1:1 scaling. 289 * Note this code adapts subsampling ratios which are powers of 2. 290 */ 291 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 292 ci++, compptr++) { 293 int ssize = cinfo->_min_DCT_scaled_size; 294 while (ssize < DCTSIZE && 295 ((cinfo->max_h_samp_factor * cinfo->_min_DCT_scaled_size) % 296 (compptr->h_samp_factor * ssize * 2) == 0) && 297 ((cinfo->max_v_samp_factor * cinfo->_min_DCT_scaled_size) % 298 (compptr->v_samp_factor * ssize * 2) == 0)) { 299 ssize = ssize * 2; 300 } 301 #if JPEG_LIB_VERSION >= 70 302 compptr->DCT_h_scaled_size = compptr->DCT_v_scaled_size = ssize; 303 #else 304 compptr->DCT_scaled_size = ssize; 305 #endif 306 } 307 308 /* Recompute downsampled dimensions of components; 309 * application needs to know these if using raw downsampled data. 310 */ 311 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 312 ci++, compptr++) { 313 /* Size in samples, after IDCT scaling */ 314 compptr->downsampled_width = (JDIMENSION) 315 jdiv_round_up((long) cinfo->image_width * 316 (long) (compptr->h_samp_factor * compptr->_DCT_scaled_size), 317 (long) (cinfo->max_h_samp_factor * DCTSIZE)); 318 compptr->downsampled_height = (JDIMENSION) 319 jdiv_round_up((long) cinfo->image_height * 320 (long) (compptr->v_samp_factor * compptr->_DCT_scaled_size), 321 (long) (cinfo->max_v_samp_factor * DCTSIZE)); 322 } 323 324 #else /* !IDCT_SCALING_SUPPORTED */ 325 326 /* Hardwire it to "no scaling" */ 327 cinfo->output_width = cinfo->image_width; 328 cinfo->output_height = cinfo->image_height; 329 /* jdinput.c has already initialized DCT_scaled_size to DCTSIZE, 330 * and has computed unscaled downsampled_width and downsampled_height. 331 */ 332 333 #endif /* IDCT_SCALING_SUPPORTED */ 334 335 /* Report number of components in selected colorspace. */ 336 /* Probably this should be in the color conversion module... */ 337 switch (cinfo->out_color_space) { 338 case JCS_GRAYSCALE: 339 cinfo->out_color_components = 1; 340 break; 341 case JCS_RGB: 342 case JCS_EXT_RGB: 343 case JCS_EXT_RGBX: 344 case JCS_EXT_BGR: 345 case JCS_EXT_BGRX: 346 case JCS_EXT_XBGR: 347 case JCS_EXT_XRGB: 348 case JCS_EXT_RGBA: 349 case JCS_EXT_BGRA: 350 case JCS_EXT_ABGR: 351 case JCS_EXT_ARGB: 352 cinfo->out_color_components = rgb_pixelsize[cinfo->out_color_space]; 353 break; 354 case JCS_YCbCr: 355 cinfo->out_color_components = 3; 356 break; 357 case JCS_CMYK: 358 case JCS_YCCK: 359 cinfo->out_color_components = 4; 360 break; 361 default: /* else must be same colorspace as in file */ 362 cinfo->out_color_components = cinfo->num_components; 363 break; 364 } 365 cinfo->output_components = (cinfo->quantize_colors ? 1 : 366 cinfo->out_color_components); 367 368 /* See if upsampler will want to emit more than one row at a time */ 369 if (use_merged_upsample(cinfo)) 370 cinfo->rec_outbuf_height = cinfo->max_v_samp_factor; 371 else 372 cinfo->rec_outbuf_height = 1; 373 } 374 375 376 /* 377 * Several decompression processes need to range-limit values to the range 378 * 0..MAXJSAMPLE; the input value may fall somewhat outside this range 379 * due to noise introduced by quantization, roundoff error, etc. These 380 * processes are inner loops and need to be as fast as possible. On most 381 * machines, particularly CPUs with pipelines or instruction prefetch, 382 * a (subscript-check-less) C table lookup 383 * x = sample_range_limit[x]; 384 * is faster than explicit tests 385 * if (x < 0) x = 0; 386 * else if (x > MAXJSAMPLE) x = MAXJSAMPLE; 387 * These processes all use a common table prepared by the routine below. 388 * 389 * For most steps we can mathematically guarantee that the initial value 390 * of x is within MAXJSAMPLE+1 of the legal range, so a table running from 391 * -(MAXJSAMPLE+1) to 2*MAXJSAMPLE+1 is sufficient. But for the initial 392 * limiting step (just after the IDCT), a wildly out-of-range value is 393 * possible if the input data is corrupt. To avoid any chance of indexing 394 * off the end of memory and getting a bad-pointer trap, we perform the 395 * post-IDCT limiting thus: 396 * x = range_limit[x & MASK]; 397 * where MASK is 2 bits wider than legal sample data, ie 10 bits for 8-bit 398 * samples. Under normal circumstances this is more than enough range and 399 * a correct output will be generated; with bogus input data the mask will 400 * cause wraparound, and we will safely generate a bogus-but-in-range output. 401 * For the post-IDCT step, we want to convert the data from signed to unsigned 402 * representation by adding CENTERJSAMPLE at the same time that we limit it. 403 * So the post-IDCT limiting table ends up looking like this: 404 * CENTERJSAMPLE,CENTERJSAMPLE+1,...,MAXJSAMPLE, 405 * MAXJSAMPLE (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times), 406 * 0 (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times), 407 * 0,1,...,CENTERJSAMPLE-1 408 * Negative inputs select values from the upper half of the table after 409 * masking. 410 * 411 * We can save some space by overlapping the start of the post-IDCT table 412 * with the simpler range limiting table. The post-IDCT table begins at 413 * sample_range_limit + CENTERJSAMPLE. 414 * 415 * Note that the table is allocated in near data space on PCs; it's small 416 * enough and used often enough to justify this. 417 */ 418 419 LOCAL(void) 420 prepare_range_limit_table (j_decompress_ptr cinfo) 421 /* Allocate and fill in the sample_range_limit table */ 422 { 423 JSAMPLE * table; 424 int i; 425 426 table = (JSAMPLE *) 427 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 428 (5 * (MAXJSAMPLE+1) + CENTERJSAMPLE) * SIZEOF(JSAMPLE)); 429 table += (MAXJSAMPLE+1); /* allow negative subscripts of simple table */ 430 cinfo->sample_range_limit = table; 431 /* First segment of "simple" table: limit[x] = 0 for x < 0 */ 432 MEMZERO(table - (MAXJSAMPLE+1), (MAXJSAMPLE+1) * SIZEOF(JSAMPLE)); 433 /* Main part of "simple" table: limit[x] = x */ 434 for (i = 0; i <= MAXJSAMPLE; i++) 435 table[i] = (JSAMPLE) i; 436 table += CENTERJSAMPLE; /* Point to where post-IDCT table starts */ 437 /* End of simple table, rest of first half of post-IDCT table */ 438 for (i = CENTERJSAMPLE; i < 2*(MAXJSAMPLE+1); i++) 439 table[i] = MAXJSAMPLE; 440 /* Second half of post-IDCT table */ 441 MEMZERO(table + (2 * (MAXJSAMPLE+1)), 442 (2 * (MAXJSAMPLE+1) - CENTERJSAMPLE) * SIZEOF(JSAMPLE)); 443 MEMCOPY(table + (4 * (MAXJSAMPLE+1) - CENTERJSAMPLE), 444 cinfo->sample_range_limit, CENTERJSAMPLE * SIZEOF(JSAMPLE)); 445 } 446 447 448 /* 449 * Master selection of decompression modules. 450 * This is done once at jpeg_start_decompress time. We determine 451 * which modules will be used and give them appropriate initialization calls. 452 * We also initialize the decompressor input side to begin consuming data. 453 * 454 * Since jpeg_read_header has finished, we know what is in the SOF 455 * and (first) SOS markers. We also have all the application parameter 456 * settings. 457 */ 458 459 LOCAL(void) 460 master_selection (j_decompress_ptr cinfo) 461 { 462 my_master_ptr master = (my_master_ptr) cinfo->master; 463 boolean use_c_buffer; 464 long samplesperrow; 465 JDIMENSION jd_samplesperrow; 466 467 /* Initialize dimensions and other stuff */ 468 jpeg_calc_output_dimensions(cinfo); 469 prepare_range_limit_table(cinfo); 470 471 /* Width of an output scanline must be representable as JDIMENSION. */ 472 samplesperrow = (long) cinfo->output_width * (long) cinfo->out_color_components; 473 jd_samplesperrow = (JDIMENSION) samplesperrow; 474 if ((long) jd_samplesperrow != samplesperrow) 475 ERREXIT(cinfo, JERR_WIDTH_OVERFLOW); 476 477 /* Initialize my private state */ 478 master->pass_number = 0; 479 master->using_merged_upsample = use_merged_upsample(cinfo); 480 481 /* Color quantizer selection */ 482 master->quantizer_1pass = NULL; 483 master->quantizer_2pass = NULL; 484 /* No mode changes if not using buffered-image mode. */ 485 if (! cinfo->quantize_colors || ! cinfo->buffered_image) { 486 cinfo->enable_1pass_quant = FALSE; 487 cinfo->enable_external_quant = FALSE; 488 cinfo->enable_2pass_quant = FALSE; 489 } 490 if (cinfo->quantize_colors) { 491 if (cinfo->raw_data_out) 492 ERREXIT(cinfo, JERR_NOTIMPL); 493 /* 2-pass quantizer only works in 3-component color space. */ 494 if (cinfo->out_color_components != 3) { 495 cinfo->enable_1pass_quant = TRUE; 496 cinfo->enable_external_quant = FALSE; 497 cinfo->enable_2pass_quant = FALSE; 498 cinfo->colormap = NULL; 499 } else if (cinfo->colormap != NULL) { 500 cinfo->enable_external_quant = TRUE; 501 } else if (cinfo->two_pass_quantize) { 502 cinfo->enable_2pass_quant = TRUE; 503 } else { 504 cinfo->enable_1pass_quant = TRUE; 505 } 506 507 if (cinfo->enable_1pass_quant) { 508 #ifdef QUANT_1PASS_SUPPORTED 509 jinit_1pass_quantizer(cinfo); 510 master->quantizer_1pass = cinfo->cquantize; 511 #else 512 ERREXIT(cinfo, JERR_NOT_COMPILED); 513 #endif 514 } 515 516 /* We use the 2-pass code to map to external colormaps. */ 517 if (cinfo->enable_2pass_quant || cinfo->enable_external_quant) { 518 #ifdef QUANT_2PASS_SUPPORTED 519 jinit_2pass_quantizer(cinfo); 520 master->quantizer_2pass = cinfo->cquantize; 521 #else 522 ERREXIT(cinfo, JERR_NOT_COMPILED); 523 #endif 524 } 525 /* If both quantizers are initialized, the 2-pass one is left active; 526 * this is necessary for starting with quantization to an external map. 527 */ 528 } 529 530 /* Post-processing: in particular, color conversion first */ 531 if (! cinfo->raw_data_out) { 532 if (master->using_merged_upsample) { 533 #ifdef UPSAMPLE_MERGING_SUPPORTED 534 jinit_merged_upsampler(cinfo); /* does color conversion too */ 535 #else 536 ERREXIT(cinfo, JERR_NOT_COMPILED); 537 #endif 538 } else { 539 jinit_color_deconverter(cinfo); 540 jinit_upsampler(cinfo); 541 } 542 jinit_d_post_controller(cinfo, cinfo->enable_2pass_quant); 543 } 544 /* Inverse DCT */ 545 jinit_inverse_dct(cinfo); 546 /* Entropy decoding: either Huffman or arithmetic coding. */ 547 if (cinfo->arith_code) { 548 #ifdef D_ARITH_CODING_SUPPORTED 549 jinit_arith_decoder(cinfo); 550 #else 551 ERREXIT(cinfo, JERR_ARITH_NOTIMPL); 552 #endif 553 } else { 554 if (cinfo->progressive_mode) { 555 #ifdef D_PROGRESSIVE_SUPPORTED 556 jinit_phuff_decoder(cinfo); 557 #else 558 ERREXIT(cinfo, JERR_NOT_COMPILED); 559 #endif 560 } else 561 jinit_huff_decoder(cinfo); 562 } 563 564 /* Initialize principal buffer controllers. */ 565 use_c_buffer = cinfo->inputctl->has_multiple_scans || cinfo->buffered_image; 566 jinit_d_coef_controller(cinfo, use_c_buffer); 567 568 if (! cinfo->raw_data_out) 569 jinit_d_main_controller(cinfo, FALSE /* never need full buffer here */); 570 571 /* We can now tell the memory manager to allocate virtual arrays. */ 572 (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo); 573 574 /* Initialize input side of decompressor to consume first scan. */ 575 (*cinfo->inputctl->start_input_pass) (cinfo); 576 577 #ifdef D_MULTISCAN_FILES_SUPPORTED 578 /* If jpeg_start_decompress will read the whole file, initialize 579 * progress monitoring appropriately. The input step is counted 580 * as one pass. 581 */ 582 if (cinfo->progress != NULL && ! cinfo->buffered_image && 583 cinfo->inputctl->has_multiple_scans) { 584 int nscans; 585 /* Estimate number of scans to set pass_limit. */ 586 if (cinfo->progressive_mode) { 587 /* Arbitrarily estimate 2 interleaved DC scans + 3 AC scans/component. */ 588 nscans = 2 + 3 * cinfo->num_components; 589 } else { 590 /* For a nonprogressive multiscan file, estimate 1 scan per component. */ 591 nscans = cinfo->num_components; 592 } 593 cinfo->progress->pass_counter = 0L; 594 cinfo->progress->pass_limit = (long) cinfo->total_iMCU_rows * nscans; 595 cinfo->progress->completed_passes = 0; 596 cinfo->progress->total_passes = (cinfo->enable_2pass_quant ? 3 : 2); 597 /* Count the input pass as done */ 598 master->pass_number++; 599 } 600 #endif /* D_MULTISCAN_FILES_SUPPORTED */ 601 } 602 603 604 /* 605 * Per-pass setup. 606 * This is called at the beginning of each output pass. We determine which 607 * modules will be active during this pass and give them appropriate 608 * start_pass calls. We also set is_dummy_pass to indicate whether this 609 * is a "real" output pass or a dummy pass for color quantization. 610 * (In the latter case, jdapistd.c will crank the pass to completion.) 611 */ 612 613 METHODDEF(void) 614 prepare_for_output_pass (j_decompress_ptr cinfo) 615 { 616 my_master_ptr master = (my_master_ptr) cinfo->master; 617 618 if (master->pub.is_dummy_pass) { 619 #ifdef QUANT_2PASS_SUPPORTED 620 /* Final pass of 2-pass quantization */ 621 master->pub.is_dummy_pass = FALSE; 622 (*cinfo->cquantize->start_pass) (cinfo, FALSE); 623 (*cinfo->post->start_pass) (cinfo, JBUF_CRANK_DEST); 624 (*cinfo->main->start_pass) (cinfo, JBUF_CRANK_DEST); 625 #else 626 ERREXIT(cinfo, JERR_NOT_COMPILED); 627 #endif /* QUANT_2PASS_SUPPORTED */ 628 } else { 629 if (cinfo->quantize_colors && cinfo->colormap == NULL) { 630 /* Select new quantization method */ 631 if (cinfo->two_pass_quantize && cinfo->enable_2pass_quant) { 632 cinfo->cquantize = master->quantizer_2pass; 633 master->pub.is_dummy_pass = TRUE; 634 } else if (cinfo->enable_1pass_quant) { 635 cinfo->cquantize = master->quantizer_1pass; 636 } else { 637 ERREXIT(cinfo, JERR_MODE_CHANGE); 638 } 639 } 640 (*cinfo->idct->start_pass) (cinfo); 641 (*cinfo->coef->start_output_pass) (cinfo); 642 if (! cinfo->raw_data_out) { 643 if (! master->using_merged_upsample) 644 (*cinfo->cconvert->start_pass) (cinfo); 645 (*cinfo->upsample->start_pass) (cinfo); 646 if (cinfo->quantize_colors) 647 (*cinfo->cquantize->start_pass) (cinfo, master->pub.is_dummy_pass); 648 (*cinfo->post->start_pass) (cinfo, 649 (master->pub.is_dummy_pass ? JBUF_SAVE_AND_PASS : JBUF_PASS_THRU)); 650 (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU); 651 } 652 } 653 654 /* Set up progress monitor's pass info if present */ 655 if (cinfo->progress != NULL) { 656 cinfo->progress->completed_passes = master->pass_number; 657 cinfo->progress->total_passes = master->pass_number + 658 (master->pub.is_dummy_pass ? 2 : 1); 659 /* In buffered-image mode, we assume one more output pass if EOI not 660 * yet reached, but no more passes if EOI has been reached. 661 */ 662 if (cinfo->buffered_image && ! cinfo->inputctl->eoi_reached) { 663 cinfo->progress->total_passes += (cinfo->enable_2pass_quant ? 2 : 1); 664 } 665 } 666 } 667 668 669 /* 670 * Finish up at end of an output pass. 671 */ 672 673 METHODDEF(void) 674 finish_output_pass (j_decompress_ptr cinfo) 675 { 676 my_master_ptr master = (my_master_ptr) cinfo->master; 677 678 if (cinfo->quantize_colors) 679 (*cinfo->cquantize->finish_pass) (cinfo); 680 master->pass_number++; 681 } 682 683 684 #ifdef D_MULTISCAN_FILES_SUPPORTED 685 686 /* 687 * Switch to a new external colormap between output passes. 688 */ 689 690 GLOBAL(void) 691 jpeg_new_colormap (j_decompress_ptr cinfo) 692 { 693 my_master_ptr master = (my_master_ptr) cinfo->master; 694 695 /* Prevent application from calling me at wrong times */ 696 if (cinfo->global_state != DSTATE_BUFIMAGE) 697 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 698 699 if (cinfo->quantize_colors && cinfo->enable_external_quant && 700 cinfo->colormap != NULL) { 701 /* Select 2-pass quantizer for external colormap use */ 702 cinfo->cquantize = master->quantizer_2pass; 703 /* Notify quantizer of colormap change */ 704 (*cinfo->cquantize->new_color_map) (cinfo); 705 master->pub.is_dummy_pass = FALSE; /* just in case */ 706 } else 707 ERREXIT(cinfo, JERR_MODE_CHANGE); 708 } 709 710 #endif /* D_MULTISCAN_FILES_SUPPORTED */ 711 712 713 /* 714 * Initialize master decompression control and select active modules. 715 * This is performed at the start of jpeg_start_decompress. 716 */ 717 718 GLOBAL(void) 719 jinit_master_decompress (j_decompress_ptr cinfo) 720 { 721 my_master_ptr master; 722 723 master = (my_master_ptr) 724 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 725 SIZEOF(my_decomp_master)); 726 cinfo->master = (struct jpeg_decomp_master *) master; 727 master->pub.prepare_for_output_pass = prepare_for_output_pass; 728 master->pub.finish_output_pass = finish_output_pass; 729 730 master->pub.is_dummy_pass = FALSE; 731 732 master_selection(cinfo); 733 } 734
