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, 2016, D. R. Commander. 9 * Copyright (C) 2013, Linaro Limited. 10 * Copyright (C) 2015, Google, Inc. 11 * For conditions of distribution and use, see the accompanying README.ijg 12 * file. 13 * 14 * This file contains master control logic for the JPEG decompressor. 15 * These routines are concerned with selecting the modules to be executed 16 * and with determining the number of passes and the work to be done in each 17 * pass. 18 */ 19 20#define JPEG_INTERNALS 21#include "jinclude.h" 22#include "jpeglib.h" 23#include "jpegcomp.h" 24#include "jdmaster.h" 25 26 27/* 28 * Determine whether merged upsample/color conversion should be used. 29 * CRUCIAL: this must match the actual capabilities of jdmerge.c! 30 */ 31 32LOCAL(boolean) 33use_merged_upsample (j_decompress_ptr cinfo) 34{ 35#ifdef UPSAMPLE_MERGING_SUPPORTED 36 /* Merging is the equivalent of plain box-filter upsampling */ 37 if (cinfo->do_fancy_upsampling || cinfo->CCIR601_sampling) 38 return FALSE; 39 /* jdmerge.c only supports YCC=>RGB and YCC=>RGB565 color conversion */ 40 if (cinfo->jpeg_color_space != JCS_YCbCr || cinfo->num_components != 3 || 41 (cinfo->out_color_space != JCS_RGB && 42 cinfo->out_color_space != JCS_RGB565 && 43 cinfo->out_color_space != JCS_EXT_RGB && 44 cinfo->out_color_space != JCS_EXT_RGBX && 45 cinfo->out_color_space != JCS_EXT_BGR && 46 cinfo->out_color_space != JCS_EXT_BGRX && 47 cinfo->out_color_space != JCS_EXT_XBGR && 48 cinfo->out_color_space != JCS_EXT_XRGB && 49 cinfo->out_color_space != JCS_EXT_RGBA && 50 cinfo->out_color_space != JCS_EXT_BGRA && 51 cinfo->out_color_space != JCS_EXT_ABGR && 52 cinfo->out_color_space != JCS_EXT_ARGB)) 53 return FALSE; 54 if ((cinfo->out_color_space == JCS_RGB565 && 55 cinfo->out_color_components != 3) || 56 (cinfo->out_color_space != JCS_RGB565 && 57 cinfo->out_color_components != rgb_pixelsize[cinfo->out_color_space])) 58 return FALSE; 59 /* and it only handles 2h1v or 2h2v sampling ratios */ 60 if (cinfo->comp_info[0].h_samp_factor != 2 || 61 cinfo->comp_info[1].h_samp_factor != 1 || 62 cinfo->comp_info[2].h_samp_factor != 1 || 63 cinfo->comp_info[0].v_samp_factor > 2 || 64 cinfo->comp_info[1].v_samp_factor != 1 || 65 cinfo->comp_info[2].v_samp_factor != 1) 66 return FALSE; 67 /* furthermore, it doesn't work if we've scaled the IDCTs differently */ 68 if (cinfo->comp_info[0]._DCT_scaled_size != cinfo->_min_DCT_scaled_size || 69 cinfo->comp_info[1]._DCT_scaled_size != cinfo->_min_DCT_scaled_size || 70 cinfo->comp_info[2]._DCT_scaled_size != cinfo->_min_DCT_scaled_size) 71 return FALSE; 72 /* ??? also need to test for upsample-time rescaling, when & if supported */ 73 return TRUE; /* by golly, it'll work... */ 74#else 75 return FALSE; 76#endif 77} 78 79 80/* 81 * Compute output image dimensions and related values. 82 * NOTE: this is exported for possible use by application. 83 * Hence it mustn't do anything that can't be done twice. 84 */ 85 86#if JPEG_LIB_VERSION >= 80 87GLOBAL(void) 88#else 89LOCAL(void) 90#endif 91jpeg_core_output_dimensions (j_decompress_ptr cinfo) 92/* Do computations that are needed before master selection phase. 93 * This function is used for transcoding and full decompression. 94 */ 95{ 96#ifdef IDCT_SCALING_SUPPORTED 97 int ci; 98 jpeg_component_info *compptr; 99 100 /* Compute actual output image dimensions and DCT scaling choices. */ 101 if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom) { 102 /* Provide 1/block_size scaling */ 103 cinfo->output_width = (JDIMENSION) 104 jdiv_round_up((long) cinfo->image_width, (long) DCTSIZE); 105 cinfo->output_height = (JDIMENSION) 106 jdiv_round_up((long) cinfo->image_height, (long) DCTSIZE); 107 cinfo->_min_DCT_h_scaled_size = 1; 108 cinfo->_min_DCT_v_scaled_size = 1; 109 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 2) { 110 /* Provide 2/block_size scaling */ 111 cinfo->output_width = (JDIMENSION) 112 jdiv_round_up((long) cinfo->image_width * 2L, (long) DCTSIZE); 113 cinfo->output_height = (JDIMENSION) 114 jdiv_round_up((long) cinfo->image_height * 2L, (long) DCTSIZE); 115 cinfo->_min_DCT_h_scaled_size = 2; 116 cinfo->_min_DCT_v_scaled_size = 2; 117 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 3) { 118 /* Provide 3/block_size scaling */ 119 cinfo->output_width = (JDIMENSION) 120 jdiv_round_up((long) cinfo->image_width * 3L, (long) DCTSIZE); 121 cinfo->output_height = (JDIMENSION) 122 jdiv_round_up((long) cinfo->image_height * 3L, (long) DCTSIZE); 123 cinfo->_min_DCT_h_scaled_size = 3; 124 cinfo->_min_DCT_v_scaled_size = 3; 125 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 4) { 126 /* Provide 4/block_size scaling */ 127 cinfo->output_width = (JDIMENSION) 128 jdiv_round_up((long) cinfo->image_width * 4L, (long) DCTSIZE); 129 cinfo->output_height = (JDIMENSION) 130 jdiv_round_up((long) cinfo->image_height * 4L, (long) DCTSIZE); 131 cinfo->_min_DCT_h_scaled_size = 4; 132 cinfo->_min_DCT_v_scaled_size = 4; 133 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 5) { 134 /* Provide 5/block_size scaling */ 135 cinfo->output_width = (JDIMENSION) 136 jdiv_round_up((long) cinfo->image_width * 5L, (long) DCTSIZE); 137 cinfo->output_height = (JDIMENSION) 138 jdiv_round_up((long) cinfo->image_height * 5L, (long) DCTSIZE); 139 cinfo->_min_DCT_h_scaled_size = 5; 140 cinfo->_min_DCT_v_scaled_size = 5; 141 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 6) { 142 /* Provide 6/block_size scaling */ 143 cinfo->output_width = (JDIMENSION) 144 jdiv_round_up((long) cinfo->image_width * 6L, (long) DCTSIZE); 145 cinfo->output_height = (JDIMENSION) 146 jdiv_round_up((long) cinfo->image_height * 6L, (long) DCTSIZE); 147 cinfo->_min_DCT_h_scaled_size = 6; 148 cinfo->_min_DCT_v_scaled_size = 6; 149 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 7) { 150 /* Provide 7/block_size scaling */ 151 cinfo->output_width = (JDIMENSION) 152 jdiv_round_up((long) cinfo->image_width * 7L, (long) DCTSIZE); 153 cinfo->output_height = (JDIMENSION) 154 jdiv_round_up((long) cinfo->image_height * 7L, (long) DCTSIZE); 155 cinfo->_min_DCT_h_scaled_size = 7; 156 cinfo->_min_DCT_v_scaled_size = 7; 157 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 8) { 158 /* Provide 8/block_size scaling */ 159 cinfo->output_width = (JDIMENSION) 160 jdiv_round_up((long) cinfo->image_width * 8L, (long) DCTSIZE); 161 cinfo->output_height = (JDIMENSION) 162 jdiv_round_up((long) cinfo->image_height * 8L, (long) DCTSIZE); 163 cinfo->_min_DCT_h_scaled_size = 8; 164 cinfo->_min_DCT_v_scaled_size = 8; 165 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 9) { 166 /* Provide 9/block_size scaling */ 167 cinfo->output_width = (JDIMENSION) 168 jdiv_round_up((long) cinfo->image_width * 9L, (long) DCTSIZE); 169 cinfo->output_height = (JDIMENSION) 170 jdiv_round_up((long) cinfo->image_height * 9L, (long) DCTSIZE); 171 cinfo->_min_DCT_h_scaled_size = 9; 172 cinfo->_min_DCT_v_scaled_size = 9; 173 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 10) { 174 /* Provide 10/block_size scaling */ 175 cinfo->output_width = (JDIMENSION) 176 jdiv_round_up((long) cinfo->image_width * 10L, (long) DCTSIZE); 177 cinfo->output_height = (JDIMENSION) 178 jdiv_round_up((long) cinfo->image_height * 10L, (long) DCTSIZE); 179 cinfo->_min_DCT_h_scaled_size = 10; 180 cinfo->_min_DCT_v_scaled_size = 10; 181 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 11) { 182 /* Provide 11/block_size scaling */ 183 cinfo->output_width = (JDIMENSION) 184 jdiv_round_up((long) cinfo->image_width * 11L, (long) DCTSIZE); 185 cinfo->output_height = (JDIMENSION) 186 jdiv_round_up((long) cinfo->image_height * 11L, (long) DCTSIZE); 187 cinfo->_min_DCT_h_scaled_size = 11; 188 cinfo->_min_DCT_v_scaled_size = 11; 189 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 12) { 190 /* Provide 12/block_size scaling */ 191 cinfo->output_width = (JDIMENSION) 192 jdiv_round_up((long) cinfo->image_width * 12L, (long) DCTSIZE); 193 cinfo->output_height = (JDIMENSION) 194 jdiv_round_up((long) cinfo->image_height * 12L, (long) DCTSIZE); 195 cinfo->_min_DCT_h_scaled_size = 12; 196 cinfo->_min_DCT_v_scaled_size = 12; 197 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 13) { 198 /* Provide 13/block_size scaling */ 199 cinfo->output_width = (JDIMENSION) 200 jdiv_round_up((long) cinfo->image_width * 13L, (long) DCTSIZE); 201 cinfo->output_height = (JDIMENSION) 202 jdiv_round_up((long) cinfo->image_height * 13L, (long) DCTSIZE); 203 cinfo->_min_DCT_h_scaled_size = 13; 204 cinfo->_min_DCT_v_scaled_size = 13; 205 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 14) { 206 /* Provide 14/block_size scaling */ 207 cinfo->output_width = (JDIMENSION) 208 jdiv_round_up((long) cinfo->image_width * 14L, (long) DCTSIZE); 209 cinfo->output_height = (JDIMENSION) 210 jdiv_round_up((long) cinfo->image_height * 14L, (long) DCTSIZE); 211 cinfo->_min_DCT_h_scaled_size = 14; 212 cinfo->_min_DCT_v_scaled_size = 14; 213 } else if (cinfo->scale_num * DCTSIZE <= cinfo->scale_denom * 15) { 214 /* Provide 15/block_size scaling */ 215 cinfo->output_width = (JDIMENSION) 216 jdiv_round_up((long) cinfo->image_width * 15L, (long) DCTSIZE); 217 cinfo->output_height = (JDIMENSION) 218 jdiv_round_up((long) cinfo->image_height * 15L, (long) DCTSIZE); 219 cinfo->_min_DCT_h_scaled_size = 15; 220 cinfo->_min_DCT_v_scaled_size = 15; 221 } else { 222 /* Provide 16/block_size scaling */ 223 cinfo->output_width = (JDIMENSION) 224 jdiv_round_up((long) cinfo->image_width * 16L, (long) DCTSIZE); 225 cinfo->output_height = (JDIMENSION) 226 jdiv_round_up((long) cinfo->image_height * 16L, (long) DCTSIZE); 227 cinfo->_min_DCT_h_scaled_size = 16; 228 cinfo->_min_DCT_v_scaled_size = 16; 229 } 230 231 /* Recompute dimensions of components */ 232 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 233 ci++, compptr++) { 234 compptr->_DCT_h_scaled_size = cinfo->_min_DCT_h_scaled_size; 235 compptr->_DCT_v_scaled_size = cinfo->_min_DCT_v_scaled_size; 236 } 237 238#else /* !IDCT_SCALING_SUPPORTED */ 239 240 /* Hardwire it to "no scaling" */ 241 cinfo->output_width = cinfo->image_width; 242 cinfo->output_height = cinfo->image_height; 243 /* jdinput.c has already initialized DCT_scaled_size, 244 * and has computed unscaled downsampled_width and downsampled_height. 245 */ 246 247#endif /* IDCT_SCALING_SUPPORTED */ 248} 249 250 251/* 252 * Compute output image dimensions and related values. 253 * NOTE: this is exported for possible use by application. 254 * Hence it mustn't do anything that can't be done twice. 255 * Also note that it may be called before the master module is initialized! 256 */ 257 258GLOBAL(void) 259jpeg_calc_output_dimensions (j_decompress_ptr cinfo) 260/* Do computations that are needed before master selection phase */ 261{ 262#ifdef IDCT_SCALING_SUPPORTED 263 int ci; 264 jpeg_component_info *compptr; 265#endif 266 267 /* Prevent application from calling me at wrong times */ 268 if (cinfo->global_state != DSTATE_READY) 269 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 270 271 /* Compute core output image dimensions and DCT scaling choices. */ 272 jpeg_core_output_dimensions(cinfo); 273 274#ifdef IDCT_SCALING_SUPPORTED 275 276 /* In selecting the actual DCT scaling for each component, we try to 277 * scale up the chroma components via IDCT scaling rather than upsampling. 278 * This saves time if the upsampler gets to use 1:1 scaling. 279 * Note this code adapts subsampling ratios which are powers of 2. 280 */ 281 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 282 ci++, compptr++) { 283 int ssize = cinfo->_min_DCT_scaled_size; 284 while (ssize < DCTSIZE && 285 ((cinfo->max_h_samp_factor * cinfo->_min_DCT_scaled_size) % 286 (compptr->h_samp_factor * ssize * 2) == 0) && 287 ((cinfo->max_v_samp_factor * cinfo->_min_DCT_scaled_size) % 288 (compptr->v_samp_factor * ssize * 2) == 0)) { 289 ssize = ssize * 2; 290 } 291#if JPEG_LIB_VERSION >= 70 292 compptr->DCT_h_scaled_size = compptr->DCT_v_scaled_size = ssize; 293#else 294 compptr->DCT_scaled_size = ssize; 295#endif 296 } 297 298 /* Recompute downsampled dimensions of components; 299 * application needs to know these if using raw downsampled data. 300 */ 301 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 302 ci++, compptr++) { 303 /* Size in samples, after IDCT scaling */ 304 compptr->downsampled_width = (JDIMENSION) 305 jdiv_round_up((long) cinfo->image_width * 306 (long) (compptr->h_samp_factor * compptr->_DCT_scaled_size), 307 (long) (cinfo->max_h_samp_factor * DCTSIZE)); 308 compptr->downsampled_height = (JDIMENSION) 309 jdiv_round_up((long) cinfo->image_height * 310 (long) (compptr->v_samp_factor * compptr->_DCT_scaled_size), 311 (long) (cinfo->max_v_samp_factor * DCTSIZE)); 312 } 313 314#else /* !IDCT_SCALING_SUPPORTED */ 315 316 /* Hardwire it to "no scaling" */ 317 cinfo->output_width = cinfo->image_width; 318 cinfo->output_height = cinfo->image_height; 319 /* jdinput.c has already initialized DCT_scaled_size to DCTSIZE, 320 * and has computed unscaled downsampled_width and downsampled_height. 321 */ 322 323#endif /* IDCT_SCALING_SUPPORTED */ 324 325 /* Report number of components in selected colorspace. */ 326 /* Probably this should be in the color conversion module... */ 327 switch (cinfo->out_color_space) { 328 case JCS_GRAYSCALE: 329 cinfo->out_color_components = 1; 330 break; 331 case JCS_RGB: 332 case JCS_EXT_RGB: 333 case JCS_EXT_RGBX: 334 case JCS_EXT_BGR: 335 case JCS_EXT_BGRX: 336 case JCS_EXT_XBGR: 337 case JCS_EXT_XRGB: 338 case JCS_EXT_RGBA: 339 case JCS_EXT_BGRA: 340 case JCS_EXT_ABGR: 341 case JCS_EXT_ARGB: 342 cinfo->out_color_components = rgb_pixelsize[cinfo->out_color_space]; 343 break; 344 case JCS_YCbCr: 345 case JCS_RGB565: 346 cinfo->out_color_components = 3; 347 break; 348 case JCS_CMYK: 349 case JCS_YCCK: 350 cinfo->out_color_components = 4; 351 break; 352 default: /* else must be same colorspace as in file */ 353 cinfo->out_color_components = cinfo->num_components; 354 break; 355 } 356 cinfo->output_components = (cinfo->quantize_colors ? 1 : 357 cinfo->out_color_components); 358 359 /* See if upsampler will want to emit more than one row at a time */ 360 if (use_merged_upsample(cinfo)) 361 cinfo->rec_outbuf_height = cinfo->max_v_samp_factor; 362 else 363 cinfo->rec_outbuf_height = 1; 364} 365 366 367/* 368 * Several decompression processes need to range-limit values to the range 369 * 0..MAXJSAMPLE; the input value may fall somewhat outside this range 370 * due to noise introduced by quantization, roundoff error, etc. These 371 * processes are inner loops and need to be as fast as possible. On most 372 * machines, particularly CPUs with pipelines or instruction prefetch, 373 * a (subscript-check-less) C table lookup 374 * x = sample_range_limit[x]; 375 * is faster than explicit tests 376 * if (x < 0) x = 0; 377 * else if (x > MAXJSAMPLE) x = MAXJSAMPLE; 378 * These processes all use a common table prepared by the routine below. 379 * 380 * For most steps we can mathematically guarantee that the initial value 381 * of x is within MAXJSAMPLE+1 of the legal range, so a table running from 382 * -(MAXJSAMPLE+1) to 2*MAXJSAMPLE+1 is sufficient. But for the initial 383 * limiting step (just after the IDCT), a wildly out-of-range value is 384 * possible if the input data is corrupt. To avoid any chance of indexing 385 * off the end of memory and getting a bad-pointer trap, we perform the 386 * post-IDCT limiting thus: 387 * x = range_limit[x & MASK]; 388 * where MASK is 2 bits wider than legal sample data, ie 10 bits for 8-bit 389 * samples. Under normal circumstances this is more than enough range and 390 * a correct output will be generated; with bogus input data the mask will 391 * cause wraparound, and we will safely generate a bogus-but-in-range output. 392 * For the post-IDCT step, we want to convert the data from signed to unsigned 393 * representation by adding CENTERJSAMPLE at the same time that we limit it. 394 * So the post-IDCT limiting table ends up looking like this: 395 * CENTERJSAMPLE,CENTERJSAMPLE+1,...,MAXJSAMPLE, 396 * MAXJSAMPLE (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times), 397 * 0 (repeat 2*(MAXJSAMPLE+1)-CENTERJSAMPLE times), 398 * 0,1,...,CENTERJSAMPLE-1 399 * Negative inputs select values from the upper half of the table after 400 * masking. 401 * 402 * We can save some space by overlapping the start of the post-IDCT table 403 * with the simpler range limiting table. The post-IDCT table begins at 404 * sample_range_limit + CENTERJSAMPLE. 405 */ 406 407LOCAL(void) 408prepare_range_limit_table (j_decompress_ptr cinfo) 409/* Allocate and fill in the sample_range_limit table */ 410{ 411 JSAMPLE * table; 412 int i; 413 414 table = (JSAMPLE *) 415 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 416 (5 * (MAXJSAMPLE+1) + CENTERJSAMPLE) * sizeof(JSAMPLE)); 417 table += (MAXJSAMPLE+1); /* allow negative subscripts of simple table */ 418 cinfo->sample_range_limit = table; 419 /* First segment of "simple" table: limit[x] = 0 for x < 0 */ 420 MEMZERO(table - (MAXJSAMPLE+1), (MAXJSAMPLE+1) * sizeof(JSAMPLE)); 421 /* Main part of "simple" table: limit[x] = x */ 422 for (i = 0; i <= MAXJSAMPLE; i++) 423 table[i] = (JSAMPLE) i; 424 table += CENTERJSAMPLE; /* Point to where post-IDCT table starts */ 425 /* End of simple table, rest of first half of post-IDCT table */ 426 for (i = CENTERJSAMPLE; i < 2*(MAXJSAMPLE+1); i++) 427 table[i] = MAXJSAMPLE; 428 /* Second half of post-IDCT table */ 429 MEMZERO(table + (2 * (MAXJSAMPLE+1)), 430 (2 * (MAXJSAMPLE+1) - CENTERJSAMPLE) * sizeof(JSAMPLE)); 431 MEMCOPY(table + (4 * (MAXJSAMPLE+1) - CENTERJSAMPLE), 432 cinfo->sample_range_limit, CENTERJSAMPLE * sizeof(JSAMPLE)); 433} 434 435 436/* 437 * Master selection of decompression modules. 438 * This is done once at jpeg_start_decompress time. We determine 439 * which modules will be used and give them appropriate initialization calls. 440 * We also initialize the decompressor input side to begin consuming data. 441 * 442 * Since jpeg_read_header has finished, we know what is in the SOF 443 * and (first) SOS markers. We also have all the application parameter 444 * settings. 445 */ 446 447LOCAL(void) 448master_selection (j_decompress_ptr cinfo) 449{ 450 my_master_ptr master = (my_master_ptr) cinfo->master; 451 boolean use_c_buffer; 452 long samplesperrow; 453 JDIMENSION jd_samplesperrow; 454 455 /* Initialize dimensions and other stuff */ 456 jpeg_calc_output_dimensions(cinfo); 457 prepare_range_limit_table(cinfo); 458 459 /* Width of an output scanline must be representable as JDIMENSION. */ 460 samplesperrow = (long) cinfo->output_width * (long) cinfo->out_color_components; 461 jd_samplesperrow = (JDIMENSION) samplesperrow; 462 if ((long) jd_samplesperrow != samplesperrow) 463 ERREXIT(cinfo, JERR_WIDTH_OVERFLOW); 464 465 /* Initialize my private state */ 466 master->pass_number = 0; 467 master->using_merged_upsample = use_merged_upsample(cinfo); 468 469 /* Color quantizer selection */ 470 master->quantizer_1pass = NULL; 471 master->quantizer_2pass = NULL; 472 /* No mode changes if not using buffered-image mode. */ 473 if (! cinfo->quantize_colors || ! cinfo->buffered_image) { 474 cinfo->enable_1pass_quant = FALSE; 475 cinfo->enable_external_quant = FALSE; 476 cinfo->enable_2pass_quant = FALSE; 477 } 478 if (cinfo->quantize_colors) { 479 if (cinfo->raw_data_out) 480 ERREXIT(cinfo, JERR_NOTIMPL); 481 /* 2-pass quantizer only works in 3-component color space. */ 482 if (cinfo->out_color_components != 3) { 483 cinfo->enable_1pass_quant = TRUE; 484 cinfo->enable_external_quant = FALSE; 485 cinfo->enable_2pass_quant = FALSE; 486 cinfo->colormap = NULL; 487 } else if (cinfo->colormap != NULL) { 488 cinfo->enable_external_quant = TRUE; 489 } else if (cinfo->two_pass_quantize) { 490 cinfo->enable_2pass_quant = TRUE; 491 } else { 492 cinfo->enable_1pass_quant = TRUE; 493 } 494 495 if (cinfo->enable_1pass_quant) { 496#ifdef QUANT_1PASS_SUPPORTED 497 jinit_1pass_quantizer(cinfo); 498 master->quantizer_1pass = cinfo->cquantize; 499#else 500 ERREXIT(cinfo, JERR_NOT_COMPILED); 501#endif 502 } 503 504 /* We use the 2-pass code to map to external colormaps. */ 505 if (cinfo->enable_2pass_quant || cinfo->enable_external_quant) { 506#ifdef QUANT_2PASS_SUPPORTED 507 jinit_2pass_quantizer(cinfo); 508 master->quantizer_2pass = cinfo->cquantize; 509#else 510 ERREXIT(cinfo, JERR_NOT_COMPILED); 511#endif 512 } 513 /* If both quantizers are initialized, the 2-pass one is left active; 514 * this is necessary for starting with quantization to an external map. 515 */ 516 } 517 518 /* Post-processing: in particular, color conversion first */ 519 if (! cinfo->raw_data_out) { 520 if (master->using_merged_upsample) { 521#ifdef UPSAMPLE_MERGING_SUPPORTED 522 jinit_merged_upsampler(cinfo); /* does color conversion too */ 523#else 524 ERREXIT(cinfo, JERR_NOT_COMPILED); 525#endif 526 } else { 527 jinit_color_deconverter(cinfo); 528 jinit_upsampler(cinfo); 529 } 530 jinit_d_post_controller(cinfo, cinfo->enable_2pass_quant); 531 } 532 /* Inverse DCT */ 533 jinit_inverse_dct(cinfo); 534 /* Entropy decoding: either Huffman or arithmetic coding. */ 535 if (cinfo->arith_code) { 536#ifdef D_ARITH_CODING_SUPPORTED 537 jinit_arith_decoder(cinfo); 538#else 539 ERREXIT(cinfo, JERR_ARITH_NOTIMPL); 540#endif 541 } else { 542 if (cinfo->progressive_mode) { 543#ifdef D_PROGRESSIVE_SUPPORTED 544 jinit_phuff_decoder(cinfo); 545#else 546 ERREXIT(cinfo, JERR_NOT_COMPILED); 547#endif 548 } else 549 jinit_huff_decoder(cinfo); 550 } 551 552 /* Initialize principal buffer controllers. */ 553 use_c_buffer = cinfo->inputctl->has_multiple_scans || cinfo->buffered_image; 554 jinit_d_coef_controller(cinfo, use_c_buffer); 555 556 if (! cinfo->raw_data_out) 557 jinit_d_main_controller(cinfo, FALSE /* never need full buffer here */); 558 559 /* We can now tell the memory manager to allocate virtual arrays. */ 560 (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo); 561 562 /* Initialize input side of decompressor to consume first scan. */ 563 (*cinfo->inputctl->start_input_pass) (cinfo); 564 565 /* Set the first and last iMCU columns to decompress from single-scan images. 566 * By default, decompress all of the iMCU columns. 567 */ 568 cinfo->master->first_iMCU_col = 0; 569 cinfo->master->last_iMCU_col = cinfo->MCUs_per_row - 1; 570 571#ifdef D_MULTISCAN_FILES_SUPPORTED 572 /* If jpeg_start_decompress will read the whole file, initialize 573 * progress monitoring appropriately. The input step is counted 574 * as one pass. 575 */ 576 if (cinfo->progress != NULL && ! cinfo->buffered_image && 577 cinfo->inputctl->has_multiple_scans) { 578 int nscans; 579 /* Estimate number of scans to set pass_limit. */ 580 if (cinfo->progressive_mode) { 581 /* Arbitrarily estimate 2 interleaved DC scans + 3 AC scans/component. */ 582 nscans = 2 + 3 * cinfo->num_components; 583 } else { 584 /* For a nonprogressive multiscan file, estimate 1 scan per component. */ 585 nscans = cinfo->num_components; 586 } 587 cinfo->progress->pass_counter = 0L; 588 cinfo->progress->pass_limit = (long) cinfo->total_iMCU_rows * nscans; 589 cinfo->progress->completed_passes = 0; 590 cinfo->progress->total_passes = (cinfo->enable_2pass_quant ? 3 : 2); 591 /* Count the input pass as done */ 592 master->pass_number++; 593 } 594#endif /* D_MULTISCAN_FILES_SUPPORTED */ 595} 596 597 598/* 599 * Per-pass setup. 600 * This is called at the beginning of each output pass. We determine which 601 * modules will be active during this pass and give them appropriate 602 * start_pass calls. We also set is_dummy_pass to indicate whether this 603 * is a "real" output pass or a dummy pass for color quantization. 604 * (In the latter case, jdapistd.c will crank the pass to completion.) 605 */ 606 607METHODDEF(void) 608prepare_for_output_pass (j_decompress_ptr cinfo) 609{ 610 my_master_ptr master = (my_master_ptr) cinfo->master; 611 612 if (master->pub.is_dummy_pass) { 613#ifdef QUANT_2PASS_SUPPORTED 614 /* Final pass of 2-pass quantization */ 615 master->pub.is_dummy_pass = FALSE; 616 (*cinfo->cquantize->start_pass) (cinfo, FALSE); 617 (*cinfo->post->start_pass) (cinfo, JBUF_CRANK_DEST); 618 (*cinfo->main->start_pass) (cinfo, JBUF_CRANK_DEST); 619#else 620 ERREXIT(cinfo, JERR_NOT_COMPILED); 621#endif /* QUANT_2PASS_SUPPORTED */ 622 } else { 623 if (cinfo->quantize_colors && cinfo->colormap == NULL) { 624 /* Select new quantization method */ 625 if (cinfo->two_pass_quantize && cinfo->enable_2pass_quant) { 626 cinfo->cquantize = master->quantizer_2pass; 627 master->pub.is_dummy_pass = TRUE; 628 } else if (cinfo->enable_1pass_quant) { 629 cinfo->cquantize = master->quantizer_1pass; 630 } else { 631 ERREXIT(cinfo, JERR_MODE_CHANGE); 632 } 633 } 634 (*cinfo->idct->start_pass) (cinfo); 635 (*cinfo->coef->start_output_pass) (cinfo); 636 if (! cinfo->raw_data_out) { 637 if (! master->using_merged_upsample) 638 (*cinfo->cconvert->start_pass) (cinfo); 639 (*cinfo->upsample->start_pass) (cinfo); 640 if (cinfo->quantize_colors) 641 (*cinfo->cquantize->start_pass) (cinfo, master->pub.is_dummy_pass); 642 (*cinfo->post->start_pass) (cinfo, 643 (master->pub.is_dummy_pass ? JBUF_SAVE_AND_PASS : JBUF_PASS_THRU)); 644 (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU); 645 } 646 } 647 648 /* Set up progress monitor's pass info if present */ 649 if (cinfo->progress != NULL) { 650 cinfo->progress->completed_passes = master->pass_number; 651 cinfo->progress->total_passes = master->pass_number + 652 (master->pub.is_dummy_pass ? 2 : 1); 653 /* In buffered-image mode, we assume one more output pass if EOI not 654 * yet reached, but no more passes if EOI has been reached. 655 */ 656 if (cinfo->buffered_image && ! cinfo->inputctl->eoi_reached) { 657 cinfo->progress->total_passes += (cinfo->enable_2pass_quant ? 2 : 1); 658 } 659 } 660} 661 662 663/* 664 * Finish up at end of an output pass. 665 */ 666 667METHODDEF(void) 668finish_output_pass (j_decompress_ptr cinfo) 669{ 670 my_master_ptr master = (my_master_ptr) cinfo->master; 671 672 if (cinfo->quantize_colors) 673 (*cinfo->cquantize->finish_pass) (cinfo); 674 master->pass_number++; 675} 676 677 678#ifdef D_MULTISCAN_FILES_SUPPORTED 679 680/* 681 * Switch to a new external colormap between output passes. 682 */ 683 684GLOBAL(void) 685jpeg_new_colormap (j_decompress_ptr cinfo) 686{ 687 my_master_ptr master = (my_master_ptr) cinfo->master; 688 689 /* Prevent application from calling me at wrong times */ 690 if (cinfo->global_state != DSTATE_BUFIMAGE) 691 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 692 693 if (cinfo->quantize_colors && cinfo->enable_external_quant && 694 cinfo->colormap != NULL) { 695 /* Select 2-pass quantizer for external colormap use */ 696 cinfo->cquantize = master->quantizer_2pass; 697 /* Notify quantizer of colormap change */ 698 (*cinfo->cquantize->new_color_map) (cinfo); 699 master->pub.is_dummy_pass = FALSE; /* just in case */ 700 } else 701 ERREXIT(cinfo, JERR_MODE_CHANGE); 702} 703 704#endif /* D_MULTISCAN_FILES_SUPPORTED */ 705 706 707/* 708 * Initialize master decompression control and select active modules. 709 * This is performed at the start of jpeg_start_decompress. 710 */ 711 712GLOBAL(void) 713jinit_master_decompress (j_decompress_ptr cinfo) 714{ 715 my_master_ptr master = (my_master_ptr) cinfo->master; 716 717 master->pub.prepare_for_output_pass = prepare_for_output_pass; 718 master->pub.finish_output_pass = finish_output_pass; 719 720 master->pub.is_dummy_pass = FALSE; 721 master->pub.jinit_upsampler_no_alloc = FALSE; 722 723 master_selection(cinfo); 724} 725