1 /* 2 * jcmaster.c 3 * 4 * This file was part of the Independent JPEG Group's software: 5 * Copyright (C) 1991-1997, Thomas G. Lane. 6 * Modified 2003-2010 by Guido Vollbeding. 7 * libjpeg-turbo Modifications: 8 * Copyright (C) 2010, 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 compressor. 12 * These routines are concerned with parameter validation, initial setup, 13 * and inter-pass control (determining the number of passes and the work 14 * to be done in each 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 enum { 26 main_pass, /* input data, also do first output step */ 27 huff_opt_pass, /* Huffman code optimization pass */ 28 output_pass /* data output pass */ 29 } c_pass_type; 30 31 typedef struct { 32 struct jpeg_comp_master pub; /* public fields */ 33 34 c_pass_type pass_type; /* the type of the current pass */ 35 36 int pass_number; /* # of passes completed */ 37 int total_passes; /* total # of passes needed */ 38 39 int scan_number; /* current index in scan_info[] */ 40 } my_comp_master; 41 42 typedef my_comp_master * my_master_ptr; 43 44 45 /* 46 * Support routines that do various essential calculations. 47 */ 48 49 #if JPEG_LIB_VERSION >= 70 50 /* 51 * Compute JPEG image dimensions and related values. 52 * NOTE: this is exported for possible use by application. 53 * Hence it mustn't do anything that can't be done twice. 54 */ 55 56 GLOBAL(void) 57 jpeg_calc_jpeg_dimensions (j_compress_ptr cinfo) 58 /* Do computations that are needed before master selection phase */ 59 { 60 /* Hardwire it to "no scaling" */ 61 cinfo->jpeg_width = cinfo->image_width; 62 cinfo->jpeg_height = cinfo->image_height; 63 cinfo->min_DCT_h_scaled_size = DCTSIZE; 64 cinfo->min_DCT_v_scaled_size = DCTSIZE; 65 } 66 #endif 67 68 69 LOCAL(void) 70 initial_setup (j_compress_ptr cinfo, boolean transcode_only) 71 /* Do computations that are needed before master selection phase */ 72 { 73 int ci; 74 jpeg_component_info *compptr; 75 long samplesperrow; 76 JDIMENSION jd_samplesperrow; 77 78 #if JPEG_LIB_VERSION >= 70 79 #if JPEG_LIB_VERSION >= 80 80 if (!transcode_only) 81 #endif 82 jpeg_calc_jpeg_dimensions(cinfo); 83 #endif 84 85 /* Sanity check on image dimensions */ 86 if (cinfo->_jpeg_height <= 0 || cinfo->_jpeg_width <= 0 87 || cinfo->num_components <= 0 || cinfo->input_components <= 0) 88 ERREXIT(cinfo, JERR_EMPTY_IMAGE); 89 90 /* Make sure image isn't bigger than I can handle */ 91 if ((long) cinfo->_jpeg_height > (long) JPEG_MAX_DIMENSION || 92 (long) cinfo->_jpeg_width > (long) JPEG_MAX_DIMENSION) 93 ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION); 94 95 /* Width of an input scanline must be representable as JDIMENSION. */ 96 samplesperrow = (long) cinfo->image_width * (long) cinfo->input_components; 97 jd_samplesperrow = (JDIMENSION) samplesperrow; 98 if ((long) jd_samplesperrow != samplesperrow) 99 ERREXIT(cinfo, JERR_WIDTH_OVERFLOW); 100 101 /* For now, precision must match compiled-in value... */ 102 if (cinfo->data_precision != BITS_IN_JSAMPLE) 103 ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision); 104 105 /* Check that number of components won't exceed internal array sizes */ 106 if (cinfo->num_components > MAX_COMPONENTS) 107 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components, 108 MAX_COMPONENTS); 109 110 /* Compute maximum sampling factors; check factor validity */ 111 cinfo->max_h_samp_factor = 1; 112 cinfo->max_v_samp_factor = 1; 113 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 114 ci++, compptr++) { 115 if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR || 116 compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR) 117 ERREXIT(cinfo, JERR_BAD_SAMPLING); 118 cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor, 119 compptr->h_samp_factor); 120 cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor, 121 compptr->v_samp_factor); 122 } 123 124 /* Compute dimensions of components */ 125 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 126 ci++, compptr++) { 127 /* Fill in the correct component_index value; don't rely on application */ 128 compptr->component_index = ci; 129 /* For compression, we never do DCT scaling. */ 130 #if JPEG_LIB_VERSION >= 70 131 compptr->DCT_h_scaled_size = compptr->DCT_v_scaled_size = DCTSIZE; 132 #else 133 compptr->DCT_scaled_size = DCTSIZE; 134 #endif 135 /* Size in DCT blocks */ 136 compptr->width_in_blocks = (JDIMENSION) 137 jdiv_round_up((long) cinfo->_jpeg_width * (long) compptr->h_samp_factor, 138 (long) (cinfo->max_h_samp_factor * DCTSIZE)); 139 compptr->height_in_blocks = (JDIMENSION) 140 jdiv_round_up((long) cinfo->_jpeg_height * (long) compptr->v_samp_factor, 141 (long) (cinfo->max_v_samp_factor * DCTSIZE)); 142 /* Size in samples */ 143 compptr->downsampled_width = (JDIMENSION) 144 jdiv_round_up((long) cinfo->_jpeg_width * (long) compptr->h_samp_factor, 145 (long) cinfo->max_h_samp_factor); 146 compptr->downsampled_height = (JDIMENSION) 147 jdiv_round_up((long) cinfo->_jpeg_height * (long) compptr->v_samp_factor, 148 (long) cinfo->max_v_samp_factor); 149 /* Mark component needed (this flag isn't actually used for compression) */ 150 compptr->component_needed = TRUE; 151 } 152 153 /* Compute number of fully interleaved MCU rows (number of times that 154 * main controller will call coefficient controller). 155 */ 156 cinfo->total_iMCU_rows = (JDIMENSION) 157 jdiv_round_up((long) cinfo->_jpeg_height, 158 (long) (cinfo->max_v_samp_factor*DCTSIZE)); 159 } 160 161 162 #ifdef C_MULTISCAN_FILES_SUPPORTED 163 164 LOCAL(void) 165 validate_script (j_compress_ptr cinfo) 166 /* Verify that the scan script in cinfo->scan_info[] is valid; also 167 * determine whether it uses progressive JPEG, and set cinfo->progressive_mode. 168 */ 169 { 170 const jpeg_scan_info * scanptr; 171 int scanno, ncomps, ci, coefi, thisi; 172 int Ss, Se, Ah, Al; 173 boolean component_sent[MAX_COMPONENTS]; 174 #ifdef C_PROGRESSIVE_SUPPORTED 175 int * last_bitpos_ptr; 176 int last_bitpos[MAX_COMPONENTS][DCTSIZE2]; 177 /* -1 until that coefficient has been seen; then last Al for it */ 178 #endif 179 180 if (cinfo->num_scans <= 0) 181 ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, 0); 182 183 /* For sequential JPEG, all scans must have Ss=0, Se=DCTSIZE2-1; 184 * for progressive JPEG, no scan can have this. 185 */ 186 scanptr = cinfo->scan_info; 187 if (scanptr->Ss != 0 || scanptr->Se != DCTSIZE2-1) { 188 #ifdef C_PROGRESSIVE_SUPPORTED 189 cinfo->progressive_mode = TRUE; 190 last_bitpos_ptr = & last_bitpos[0][0]; 191 for (ci = 0; ci < cinfo->num_components; ci++) 192 for (coefi = 0; coefi < DCTSIZE2; coefi++) 193 *last_bitpos_ptr++ = -1; 194 #else 195 ERREXIT(cinfo, JERR_NOT_COMPILED); 196 #endif 197 } else { 198 cinfo->progressive_mode = FALSE; 199 for (ci = 0; ci < cinfo->num_components; ci++) 200 component_sent[ci] = FALSE; 201 } 202 203 for (scanno = 1; scanno <= cinfo->num_scans; scanptr++, scanno++) { 204 /* Validate component indexes */ 205 ncomps = scanptr->comps_in_scan; 206 if (ncomps <= 0 || ncomps > MAX_COMPS_IN_SCAN) 207 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, ncomps, MAX_COMPS_IN_SCAN); 208 for (ci = 0; ci < ncomps; ci++) { 209 thisi = scanptr->component_index[ci]; 210 if (thisi < 0 || thisi >= cinfo->num_components) 211 ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno); 212 /* Components must appear in SOF order within each scan */ 213 if (ci > 0 && thisi <= scanptr->component_index[ci-1]) 214 ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno); 215 } 216 /* Validate progression parameters */ 217 Ss = scanptr->Ss; 218 Se = scanptr->Se; 219 Ah = scanptr->Ah; 220 Al = scanptr->Al; 221 if (cinfo->progressive_mode) { 222 #ifdef C_PROGRESSIVE_SUPPORTED 223 /* The JPEG spec simply gives the ranges 0..13 for Ah and Al, but that 224 * seems wrong: the upper bound ought to depend on data precision. 225 * Perhaps they really meant 0..N+1 for N-bit precision. 226 * Here we allow 0..10 for 8-bit data; Al larger than 10 results in 227 * out-of-range reconstructed DC values during the first DC scan, 228 * which might cause problems for some decoders. 229 */ 230 #if BITS_IN_JSAMPLE == 8 231 #define MAX_AH_AL 10 232 #else 233 #define MAX_AH_AL 13 234 #endif 235 if (Ss < 0 || Ss >= DCTSIZE2 || Se < Ss || Se >= DCTSIZE2 || 236 Ah < 0 || Ah > MAX_AH_AL || Al < 0 || Al > MAX_AH_AL) 237 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno); 238 if (Ss == 0) { 239 if (Se != 0) /* DC and AC together not OK */ 240 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno); 241 } else { 242 if (ncomps != 1) /* AC scans must be for only one component */ 243 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno); 244 } 245 for (ci = 0; ci < ncomps; ci++) { 246 last_bitpos_ptr = & last_bitpos[scanptr->component_index[ci]][0]; 247 if (Ss != 0 && last_bitpos_ptr[0] < 0) /* AC without prior DC scan */ 248 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno); 249 for (coefi = Ss; coefi <= Se; coefi++) { 250 if (last_bitpos_ptr[coefi] < 0) { 251 /* first scan of this coefficient */ 252 if (Ah != 0) 253 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno); 254 } else { 255 /* not first scan */ 256 if (Ah != last_bitpos_ptr[coefi] || Al != Ah-1) 257 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno); 258 } 259 last_bitpos_ptr[coefi] = Al; 260 } 261 } 262 #endif 263 } else { 264 /* For sequential JPEG, all progression parameters must be these: */ 265 if (Ss != 0 || Se != DCTSIZE2-1 || Ah != 0 || Al != 0) 266 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno); 267 /* Make sure components are not sent twice */ 268 for (ci = 0; ci < ncomps; ci++) { 269 thisi = scanptr->component_index[ci]; 270 if (component_sent[thisi]) 271 ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno); 272 component_sent[thisi] = TRUE; 273 } 274 } 275 } 276 277 /* Now verify that everything got sent. */ 278 if (cinfo->progressive_mode) { 279 #ifdef C_PROGRESSIVE_SUPPORTED 280 /* For progressive mode, we only check that at least some DC data 281 * got sent for each component; the spec does not require that all bits 282 * of all coefficients be transmitted. Would it be wiser to enforce 283 * transmission of all coefficient bits?? 284 */ 285 for (ci = 0; ci < cinfo->num_components; ci++) { 286 if (last_bitpos[ci][0] < 0) 287 ERREXIT(cinfo, JERR_MISSING_DATA); 288 } 289 #endif 290 } else { 291 for (ci = 0; ci < cinfo->num_components; ci++) { 292 if (! component_sent[ci]) 293 ERREXIT(cinfo, JERR_MISSING_DATA); 294 } 295 } 296 } 297 298 #endif /* C_MULTISCAN_FILES_SUPPORTED */ 299 300 301 LOCAL(void) 302 select_scan_parameters (j_compress_ptr cinfo) 303 /* Set up the scan parameters for the current scan */ 304 { 305 int ci; 306 307 #ifdef C_MULTISCAN_FILES_SUPPORTED 308 if (cinfo->scan_info != NULL) { 309 /* Prepare for current scan --- the script is already validated */ 310 my_master_ptr master = (my_master_ptr) cinfo->master; 311 const jpeg_scan_info * scanptr = cinfo->scan_info + master->scan_number; 312 313 cinfo->comps_in_scan = scanptr->comps_in_scan; 314 for (ci = 0; ci < scanptr->comps_in_scan; ci++) { 315 cinfo->cur_comp_info[ci] = 316 &cinfo->comp_info[scanptr->component_index[ci]]; 317 } 318 cinfo->Ss = scanptr->Ss; 319 cinfo->Se = scanptr->Se; 320 cinfo->Ah = scanptr->Ah; 321 cinfo->Al = scanptr->Al; 322 } 323 else 324 #endif 325 { 326 /* Prepare for single sequential-JPEG scan containing all components */ 327 if (cinfo->num_components > MAX_COMPS_IN_SCAN) 328 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components, 329 MAX_COMPS_IN_SCAN); 330 cinfo->comps_in_scan = cinfo->num_components; 331 for (ci = 0; ci < cinfo->num_components; ci++) { 332 cinfo->cur_comp_info[ci] = &cinfo->comp_info[ci]; 333 } 334 cinfo->Ss = 0; 335 cinfo->Se = DCTSIZE2-1; 336 cinfo->Ah = 0; 337 cinfo->Al = 0; 338 } 339 } 340 341 342 LOCAL(void) 343 per_scan_setup (j_compress_ptr cinfo) 344 /* Do computations that are needed before processing a JPEG scan */ 345 /* cinfo->comps_in_scan and cinfo->cur_comp_info[] are already set */ 346 { 347 int ci, mcublks, tmp; 348 jpeg_component_info *compptr; 349 350 if (cinfo->comps_in_scan == 1) { 351 352 /* Noninterleaved (single-component) scan */ 353 compptr = cinfo->cur_comp_info[0]; 354 355 /* Overall image size in MCUs */ 356 cinfo->MCUs_per_row = compptr->width_in_blocks; 357 cinfo->MCU_rows_in_scan = compptr->height_in_blocks; 358 359 /* For noninterleaved scan, always one block per MCU */ 360 compptr->MCU_width = 1; 361 compptr->MCU_height = 1; 362 compptr->MCU_blocks = 1; 363 compptr->MCU_sample_width = DCTSIZE; 364 compptr->last_col_width = 1; 365 /* For noninterleaved scans, it is convenient to define last_row_height 366 * as the number of block rows present in the last iMCU row. 367 */ 368 tmp = (int) (compptr->height_in_blocks % compptr->v_samp_factor); 369 if (tmp == 0) tmp = compptr->v_samp_factor; 370 compptr->last_row_height = tmp; 371 372 /* Prepare array describing MCU composition */ 373 cinfo->blocks_in_MCU = 1; 374 cinfo->MCU_membership[0] = 0; 375 376 } else { 377 378 /* Interleaved (multi-component) scan */ 379 if (cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN) 380 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan, 381 MAX_COMPS_IN_SCAN); 382 383 /* Overall image size in MCUs */ 384 cinfo->MCUs_per_row = (JDIMENSION) 385 jdiv_round_up((long) cinfo->_jpeg_width, 386 (long) (cinfo->max_h_samp_factor*DCTSIZE)); 387 cinfo->MCU_rows_in_scan = (JDIMENSION) 388 jdiv_round_up((long) cinfo->_jpeg_height, 389 (long) (cinfo->max_v_samp_factor*DCTSIZE)); 390 391 cinfo->blocks_in_MCU = 0; 392 393 for (ci = 0; ci < cinfo->comps_in_scan; ci++) { 394 compptr = cinfo->cur_comp_info[ci]; 395 /* Sampling factors give # of blocks of component in each MCU */ 396 compptr->MCU_width = compptr->h_samp_factor; 397 compptr->MCU_height = compptr->v_samp_factor; 398 compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height; 399 compptr->MCU_sample_width = compptr->MCU_width * DCTSIZE; 400 /* Figure number of non-dummy blocks in last MCU column & row */ 401 tmp = (int) (compptr->width_in_blocks % compptr->MCU_width); 402 if (tmp == 0) tmp = compptr->MCU_width; 403 compptr->last_col_width = tmp; 404 tmp = (int) (compptr->height_in_blocks % compptr->MCU_height); 405 if (tmp == 0) tmp = compptr->MCU_height; 406 compptr->last_row_height = tmp; 407 /* Prepare array describing MCU composition */ 408 mcublks = compptr->MCU_blocks; 409 if (cinfo->blocks_in_MCU + mcublks > C_MAX_BLOCKS_IN_MCU) 410 ERREXIT(cinfo, JERR_BAD_MCU_SIZE); 411 while (mcublks-- > 0) { 412 cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci; 413 } 414 } 415 416 } 417 418 /* Convert restart specified in rows to actual MCU count. */ 419 /* Note that count must fit in 16 bits, so we provide limiting. */ 420 if (cinfo->restart_in_rows > 0) { 421 long nominal = (long) cinfo->restart_in_rows * (long) cinfo->MCUs_per_row; 422 cinfo->restart_interval = (unsigned int) MIN(nominal, 65535L); 423 } 424 } 425 426 427 /* 428 * Per-pass setup. 429 * This is called at the beginning of each pass. We determine which modules 430 * will be active during this pass and give them appropriate start_pass calls. 431 * We also set is_last_pass to indicate whether any more passes will be 432 * required. 433 */ 434 435 METHODDEF(void) 436 prepare_for_pass (j_compress_ptr cinfo) 437 { 438 my_master_ptr master = (my_master_ptr) cinfo->master; 439 440 switch (master->pass_type) { 441 case main_pass: 442 /* Initial pass: will collect input data, and do either Huffman 443 * optimization or data output for the first scan. 444 */ 445 select_scan_parameters(cinfo); 446 per_scan_setup(cinfo); 447 if (! cinfo->raw_data_in) { 448 (*cinfo->cconvert->start_pass) (cinfo); 449 (*cinfo->downsample->start_pass) (cinfo); 450 (*cinfo->prep->start_pass) (cinfo, JBUF_PASS_THRU); 451 } 452 (*cinfo->fdct->start_pass) (cinfo); 453 (*cinfo->entropy->start_pass) (cinfo, cinfo->optimize_coding); 454 (*cinfo->coef->start_pass) (cinfo, 455 (master->total_passes > 1 ? 456 JBUF_SAVE_AND_PASS : JBUF_PASS_THRU)); 457 (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU); 458 if (cinfo->optimize_coding) { 459 /* No immediate data output; postpone writing frame/scan headers */ 460 master->pub.call_pass_startup = FALSE; 461 } else { 462 /* Will write frame/scan headers at first jpeg_write_scanlines call */ 463 master->pub.call_pass_startup = TRUE; 464 } 465 break; 466 #ifdef ENTROPY_OPT_SUPPORTED 467 case huff_opt_pass: 468 /* Do Huffman optimization for a scan after the first one. */ 469 select_scan_parameters(cinfo); 470 per_scan_setup(cinfo); 471 if (cinfo->Ss != 0 || cinfo->Ah == 0 || cinfo->arith_code) { 472 (*cinfo->entropy->start_pass) (cinfo, TRUE); 473 (*cinfo->coef->start_pass) (cinfo, JBUF_CRANK_DEST); 474 master->pub.call_pass_startup = FALSE; 475 break; 476 } 477 /* Special case: Huffman DC refinement scans need no Huffman table 478 * and therefore we can skip the optimization pass for them. 479 */ 480 master->pass_type = output_pass; 481 master->pass_number++; 482 /*FALLTHROUGH*/ 483 #endif 484 case output_pass: 485 /* Do a data-output pass. */ 486 /* We need not repeat per-scan setup if prior optimization pass did it. */ 487 if (! cinfo->optimize_coding) { 488 select_scan_parameters(cinfo); 489 per_scan_setup(cinfo); 490 } 491 (*cinfo->entropy->start_pass) (cinfo, FALSE); 492 (*cinfo->coef->start_pass) (cinfo, JBUF_CRANK_DEST); 493 /* We emit frame/scan headers now */ 494 if (master->scan_number == 0) 495 (*cinfo->marker->write_frame_header) (cinfo); 496 (*cinfo->marker->write_scan_header) (cinfo); 497 master->pub.call_pass_startup = FALSE; 498 break; 499 default: 500 ERREXIT(cinfo, JERR_NOT_COMPILED); 501 } 502 503 master->pub.is_last_pass = (master->pass_number == master->total_passes-1); 504 505 /* Set up progress monitor's pass info if present */ 506 if (cinfo->progress != NULL) { 507 cinfo->progress->completed_passes = master->pass_number; 508 cinfo->progress->total_passes = master->total_passes; 509 } 510 } 511 512 513 /* 514 * Special start-of-pass hook. 515 * This is called by jpeg_write_scanlines if call_pass_startup is TRUE. 516 * In single-pass processing, we need this hook because we don't want to 517 * write frame/scan headers during jpeg_start_compress; we want to let the 518 * application write COM markers etc. between jpeg_start_compress and the 519 * jpeg_write_scanlines loop. 520 * In multi-pass processing, this routine is not used. 521 */ 522 523 METHODDEF(void) 524 pass_startup (j_compress_ptr cinfo) 525 { 526 cinfo->master->call_pass_startup = FALSE; /* reset flag so call only once */ 527 528 (*cinfo->marker->write_frame_header) (cinfo); 529 (*cinfo->marker->write_scan_header) (cinfo); 530 } 531 532 533 /* 534 * Finish up at end of pass. 535 */ 536 537 METHODDEF(void) 538 finish_pass_master (j_compress_ptr cinfo) 539 { 540 my_master_ptr master = (my_master_ptr) cinfo->master; 541 542 /* The entropy coder always needs an end-of-pass call, 543 * either to analyze statistics or to flush its output buffer. 544 */ 545 (*cinfo->entropy->finish_pass) (cinfo); 546 547 /* Update state for next pass */ 548 switch (master->pass_type) { 549 case main_pass: 550 /* next pass is either output of scan 0 (after optimization) 551 * or output of scan 1 (if no optimization). 552 */ 553 master->pass_type = output_pass; 554 if (! cinfo->optimize_coding) 555 master->scan_number++; 556 break; 557 case huff_opt_pass: 558 /* next pass is always output of current scan */ 559 master->pass_type = output_pass; 560 break; 561 case output_pass: 562 /* next pass is either optimization or output of next scan */ 563 if (cinfo->optimize_coding) 564 master->pass_type = huff_opt_pass; 565 master->scan_number++; 566 break; 567 } 568 569 master->pass_number++; 570 } 571 572 573 /* 574 * Initialize master compression control. 575 */ 576 577 GLOBAL(void) 578 jinit_c_master_control (j_compress_ptr cinfo, boolean transcode_only) 579 { 580 my_master_ptr master; 581 582 master = (my_master_ptr) 583 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 584 SIZEOF(my_comp_master)); 585 cinfo->master = (struct jpeg_comp_master *) master; 586 master->pub.prepare_for_pass = prepare_for_pass; 587 master->pub.pass_startup = pass_startup; 588 master->pub.finish_pass = finish_pass_master; 589 master->pub.is_last_pass = FALSE; 590 591 /* Validate parameters, determine derived values */ 592 initial_setup(cinfo, transcode_only); 593 594 if (cinfo->scan_info != NULL) { 595 #ifdef C_MULTISCAN_FILES_SUPPORTED 596 validate_script(cinfo); 597 #else 598 ERREXIT(cinfo, JERR_NOT_COMPILED); 599 #endif 600 } else { 601 cinfo->progressive_mode = FALSE; 602 cinfo->num_scans = 1; 603 } 604 605 if (cinfo->progressive_mode && !cinfo->arith_code) /* TEMPORARY HACK ??? */ 606 cinfo->optimize_coding = TRUE; /* assume default tables no good for progressive mode */ 607 608 /* Initialize my private state */ 609 if (transcode_only) { 610 /* no main pass in transcoding */ 611 if (cinfo->optimize_coding) 612 master->pass_type = huff_opt_pass; 613 else 614 master->pass_type = output_pass; 615 } else { 616 /* for normal compression, first pass is always this type: */ 617 master->pass_type = main_pass; 618 } 619 master->scan_number = 0; 620 master->pass_number = 0; 621 if (cinfo->optimize_coding) 622 master->total_passes = cinfo->num_scans * 2; 623 else 624 master->total_passes = cinfo->num_scans; 625 } 626
