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