1/* 2 * jcmaster.c 3 * 4 * Copyright (C) 1991-1997, Thomas G. Lane. 5 * Modified 2003-2009 by Guido Vollbeding. 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 compressor. 10 * These routines are concerned with parameter validation, initial setup, 11 * and inter-pass control (determining the number of passes and the work 12 * to be done in each pass). 13 */ 14 15#define JPEG_INTERNALS 16#include "jinclude.h" 17#include "jpeglib.h" 18 19 20/* Private state */ 21 22typedef enum { 23 main_pass, /* input data, also do first output step */ 24 huff_opt_pass, /* Huffman code optimization pass */ 25 output_pass /* data output pass */ 26} c_pass_type; 27 28typedef struct { 29 struct jpeg_comp_master pub; /* public fields */ 30 31 c_pass_type pass_type; /* the type of the current pass */ 32 33 int pass_number; /* # of passes completed */ 34 int total_passes; /* total # of passes needed */ 35 36 int scan_number; /* current index in scan_info[] */ 37} my_comp_master; 38 39typedef my_comp_master * my_master_ptr; 40 41 42/* 43 * Support routines that do various essential calculations. 44 */ 45 46/* 47 * Compute JPEG image dimensions and related values. 48 * NOTE: this is exported for possible use by application. 49 * Hence it mustn't do anything that can't be done twice. 50 */ 51 52GLOBAL(void) 53jpeg_calc_jpeg_dimensions (j_compress_ptr cinfo) 54/* Do computations that are needed before master selection phase */ 55{ 56#ifdef DCT_SCALING_SUPPORTED 57 58 /* Compute actual JPEG image dimensions and DCT scaling choices. */ 59 if (cinfo->scale_num >= cinfo->scale_denom * 8) { 60 /* Provide 8/1 scaling */ 61 cinfo->jpeg_width = cinfo->image_width << 3; 62 cinfo->jpeg_height = cinfo->image_height << 3; 63 cinfo->min_DCT_h_scaled_size = 1; 64 cinfo->min_DCT_v_scaled_size = 1; 65 } else if (cinfo->scale_num >= cinfo->scale_denom * 4) { 66 /* Provide 4/1 scaling */ 67 cinfo->jpeg_width = cinfo->image_width << 2; 68 cinfo->jpeg_height = cinfo->image_height << 2; 69 cinfo->min_DCT_h_scaled_size = 2; 70 cinfo->min_DCT_v_scaled_size = 2; 71 } else if (cinfo->scale_num * 3 >= cinfo->scale_denom * 8) { 72 /* Provide 8/3 scaling */ 73 cinfo->jpeg_width = (cinfo->image_width << 1) + (JDIMENSION) 74 jdiv_round_up((long) cinfo->image_width * 2, 3L); 75 cinfo->jpeg_height = (cinfo->image_height << 1) + (JDIMENSION) 76 jdiv_round_up((long) cinfo->image_height * 2, 3L); 77 cinfo->min_DCT_h_scaled_size = 3; 78 cinfo->min_DCT_v_scaled_size = 3; 79 } else if (cinfo->scale_num >= cinfo->scale_denom * 2) { 80 /* Provide 2/1 scaling */ 81 cinfo->jpeg_width = cinfo->image_width << 1; 82 cinfo->jpeg_height = cinfo->image_height << 1; 83 cinfo->min_DCT_h_scaled_size = 4; 84 cinfo->min_DCT_v_scaled_size = 4; 85 } else if (cinfo->scale_num * 5 >= cinfo->scale_denom * 8) { 86 /* Provide 8/5 scaling */ 87 cinfo->jpeg_width = cinfo->image_width + (JDIMENSION) 88 jdiv_round_up((long) cinfo->image_width * 3, 5L); 89 cinfo->jpeg_height = cinfo->image_height + (JDIMENSION) 90 jdiv_round_up((long) cinfo->image_height * 3, 5L); 91 cinfo->min_DCT_h_scaled_size = 5; 92 cinfo->min_DCT_v_scaled_size = 5; 93 } else if (cinfo->scale_num * 3 >= cinfo->scale_denom * 4) { 94 /* Provide 4/3 scaling */ 95 cinfo->jpeg_width = cinfo->image_width + (JDIMENSION) 96 jdiv_round_up((long) cinfo->image_width, 3L); 97 cinfo->jpeg_height = cinfo->image_height + (JDIMENSION) 98 jdiv_round_up((long) cinfo->image_height, 3L); 99 cinfo->min_DCT_h_scaled_size = 6; 100 cinfo->min_DCT_v_scaled_size = 6; 101 } else if (cinfo->scale_num * 7 >= cinfo->scale_denom * 8) { 102 /* Provide 8/7 scaling */ 103 cinfo->jpeg_width = cinfo->image_width + (JDIMENSION) 104 jdiv_round_up((long) cinfo->image_width, 7L); 105 cinfo->jpeg_height = cinfo->image_height + (JDIMENSION) 106 jdiv_round_up((long) cinfo->image_height, 7L); 107 cinfo->min_DCT_h_scaled_size = 7; 108 cinfo->min_DCT_v_scaled_size = 7; 109 } else if (cinfo->scale_num >= cinfo->scale_denom) { 110 /* Provide 1/1 scaling */ 111 cinfo->jpeg_width = cinfo->image_width; 112 cinfo->jpeg_height = cinfo->image_height; 113 cinfo->min_DCT_h_scaled_size = DCTSIZE; 114 cinfo->min_DCT_v_scaled_size = DCTSIZE; 115 } else if (cinfo->scale_num * 9 >= cinfo->scale_denom * 8) { 116 /* Provide 8/9 scaling */ 117 cinfo->jpeg_width = (JDIMENSION) 118 jdiv_round_up((long) cinfo->image_width * 8, 9L); 119 cinfo->jpeg_height = (JDIMENSION) 120 jdiv_round_up((long) cinfo->image_height * 8, 9L); 121 cinfo->min_DCT_h_scaled_size = 9; 122 cinfo->min_DCT_v_scaled_size = 9; 123 } else if (cinfo->scale_num * 5 >= cinfo->scale_denom * 4) { 124 /* Provide 4/5 scaling */ 125 cinfo->jpeg_width = (JDIMENSION) 126 jdiv_round_up((long) cinfo->image_width * 4, 5L); 127 cinfo->jpeg_height = (JDIMENSION) 128 jdiv_round_up((long) cinfo->image_height * 4, 5L); 129 cinfo->min_DCT_h_scaled_size = 10; 130 cinfo->min_DCT_v_scaled_size = 10; 131 } else if (cinfo->scale_num * 11 >= cinfo->scale_denom * 8) { 132 /* Provide 8/11 scaling */ 133 cinfo->jpeg_width = (JDIMENSION) 134 jdiv_round_up((long) cinfo->image_width * 8, 11L); 135 cinfo->jpeg_height = (JDIMENSION) 136 jdiv_round_up((long) cinfo->image_height * 8, 11L); 137 cinfo->min_DCT_h_scaled_size = 11; 138 cinfo->min_DCT_v_scaled_size = 11; 139 } else if (cinfo->scale_num * 3 >= cinfo->scale_denom * 2) { 140 /* Provide 2/3 scaling */ 141 cinfo->jpeg_width = (JDIMENSION) 142 jdiv_round_up((long) cinfo->image_width * 2, 3L); 143 cinfo->jpeg_height = (JDIMENSION) 144 jdiv_round_up((long) cinfo->image_height * 2, 3L); 145 cinfo->min_DCT_h_scaled_size = 12; 146 cinfo->min_DCT_v_scaled_size = 12; 147 } else if (cinfo->scale_num * 13 >= cinfo->scale_denom * 8) { 148 /* Provide 8/13 scaling */ 149 cinfo->jpeg_width = (JDIMENSION) 150 jdiv_round_up((long) cinfo->image_width * 8, 13L); 151 cinfo->jpeg_height = (JDIMENSION) 152 jdiv_round_up((long) cinfo->image_height * 8, 13L); 153 cinfo->min_DCT_h_scaled_size = 13; 154 cinfo->min_DCT_v_scaled_size = 13; 155 } else if (cinfo->scale_num * 7 >= cinfo->scale_denom * 4) { 156 /* Provide 4/7 scaling */ 157 cinfo->jpeg_width = (JDIMENSION) 158 jdiv_round_up((long) cinfo->image_width * 4, 7L); 159 cinfo->jpeg_height = (JDIMENSION) 160 jdiv_round_up((long) cinfo->image_height * 4, 7L); 161 cinfo->min_DCT_h_scaled_size = 14; 162 cinfo->min_DCT_v_scaled_size = 14; 163 } else if (cinfo->scale_num * 15 >= cinfo->scale_denom * 8) { 164 /* Provide 8/15 scaling */ 165 cinfo->jpeg_width = (JDIMENSION) 166 jdiv_round_up((long) cinfo->image_width * 8, 15L); 167 cinfo->jpeg_height = (JDIMENSION) 168 jdiv_round_up((long) cinfo->image_height * 8, 15L); 169 cinfo->min_DCT_h_scaled_size = 15; 170 cinfo->min_DCT_v_scaled_size = 15; 171 } else { 172 /* Provide 1/2 scaling */ 173 cinfo->jpeg_width = (JDIMENSION) 174 jdiv_round_up((long) cinfo->image_width, 2L); 175 cinfo->jpeg_height = (JDIMENSION) 176 jdiv_round_up((long) cinfo->image_height, 2L); 177 cinfo->min_DCT_h_scaled_size = 16; 178 cinfo->min_DCT_v_scaled_size = 16; 179 } 180 181#else /* !DCT_SCALING_SUPPORTED */ 182 183 /* Hardwire it to "no scaling" */ 184 cinfo->jpeg_width = cinfo->image_width; 185 cinfo->jpeg_height = cinfo->image_height; 186 cinfo->min_DCT_h_scaled_size = DCTSIZE; 187 cinfo->min_DCT_v_scaled_size = DCTSIZE; 188 189#endif /* DCT_SCALING_SUPPORTED */ 190} 191 192 193LOCAL(void) 194initial_setup (j_compress_ptr cinfo) 195/* Do computations that are needed before master selection phase */ 196{ 197 int ci, ssize; 198 jpeg_component_info *compptr; 199 long samplesperrow; 200 JDIMENSION jd_samplesperrow; 201 202 jpeg_calc_jpeg_dimensions(cinfo); 203 204 /* Sanity check on image dimensions */ 205 if (cinfo->jpeg_height <= 0 || cinfo->jpeg_width <= 0 206 || cinfo->num_components <= 0 || cinfo->input_components <= 0) 207 ERREXIT(cinfo, JERR_EMPTY_IMAGE); 208 209 /* Make sure image isn't bigger than I can handle */ 210 if ((long) cinfo->jpeg_height > (long) JPEG_MAX_DIMENSION || 211 (long) cinfo->jpeg_width > (long) JPEG_MAX_DIMENSION) 212 ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION); 213 214 /* Width of an input scanline must be representable as JDIMENSION. */ 215 samplesperrow = (long) cinfo->image_width * (long) cinfo->input_components; 216 jd_samplesperrow = (JDIMENSION) samplesperrow; 217 if ((long) jd_samplesperrow != samplesperrow) 218 ERREXIT(cinfo, JERR_WIDTH_OVERFLOW); 219 220 /* For now, precision must match compiled-in value... */ 221 if (cinfo->data_precision != BITS_IN_JSAMPLE) 222 ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision); 223 224 /* Check that number of components won't exceed internal array sizes */ 225 if (cinfo->num_components > MAX_COMPONENTS) 226 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components, 227 MAX_COMPONENTS); 228 229 /* Compute maximum sampling factors; check factor validity */ 230 cinfo->max_h_samp_factor = 1; 231 cinfo->max_v_samp_factor = 1; 232 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 233 ci++, compptr++) { 234 if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR || 235 compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR) 236 ERREXIT(cinfo, JERR_BAD_SAMPLING); 237 cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor, 238 compptr->h_samp_factor); 239 cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor, 240 compptr->v_samp_factor); 241 } 242 243 /* Compute dimensions of components */ 244 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 245 ci++, compptr++) { 246 /* Fill in the correct component_index value; don't rely on application */ 247 compptr->component_index = ci; 248 /* In selecting the actual DCT scaling for each component, we try to 249 * scale down the chroma components via DCT scaling rather than downsampling. 250 * This saves time if the downsampler gets to use 1:1 scaling. 251 * Note this code adapts subsampling ratios which are powers of 2. 252 */ 253 ssize = 1; 254#ifdef DCT_SCALING_SUPPORTED 255 while (cinfo->min_DCT_h_scaled_size * ssize <= 256 (cinfo->do_fancy_downsampling ? DCTSIZE : DCTSIZE / 2) && 257 (cinfo->max_h_samp_factor % (compptr->h_samp_factor * ssize * 2)) == 0) { 258 ssize = ssize * 2; 259 } 260#endif 261 compptr->DCT_h_scaled_size = cinfo->min_DCT_h_scaled_size * ssize; 262 ssize = 1; 263#ifdef DCT_SCALING_SUPPORTED 264 while (cinfo->min_DCT_v_scaled_size * ssize <= 265 (cinfo->do_fancy_downsampling ? DCTSIZE : DCTSIZE / 2) && 266 (cinfo->max_v_samp_factor % (compptr->v_samp_factor * ssize * 2)) == 0) { 267 ssize = ssize * 2; 268 } 269#endif 270 compptr->DCT_v_scaled_size = cinfo->min_DCT_v_scaled_size * ssize; 271 272 /* We don't support DCT ratios larger than 2. */ 273 if (compptr->DCT_h_scaled_size > compptr->DCT_v_scaled_size * 2) 274 compptr->DCT_h_scaled_size = compptr->DCT_v_scaled_size * 2; 275 else if (compptr->DCT_v_scaled_size > compptr->DCT_h_scaled_size * 2) 276 compptr->DCT_v_scaled_size = compptr->DCT_h_scaled_size * 2; 277 278 /* Size in DCT blocks */ 279 compptr->width_in_blocks = (JDIMENSION) 280 jdiv_round_up((long) cinfo->jpeg_width * (long) compptr->h_samp_factor, 281 (long) (cinfo->max_h_samp_factor * DCTSIZE)); 282 compptr->height_in_blocks = (JDIMENSION) 283 jdiv_round_up((long) cinfo->jpeg_height * (long) compptr->v_samp_factor, 284 (long) (cinfo->max_v_samp_factor * DCTSIZE)); 285 /* Size in samples */ 286 compptr->downsampled_width = (JDIMENSION) 287 jdiv_round_up((long) cinfo->jpeg_width * 288 (long) (compptr->h_samp_factor * compptr->DCT_h_scaled_size), 289 (long) (cinfo->max_h_samp_factor * DCTSIZE)); 290 compptr->downsampled_height = (JDIMENSION) 291 jdiv_round_up((long) cinfo->jpeg_height * 292 (long) (compptr->v_samp_factor * compptr->DCT_v_scaled_size), 293 (long) (cinfo->max_v_samp_factor * DCTSIZE)); 294 /* Mark component needed (this flag isn't actually used for compression) */ 295 compptr->component_needed = TRUE; 296 } 297 298 /* Compute number of fully interleaved MCU rows (number of times that 299 * main controller will call coefficient controller). 300 */ 301 cinfo->total_iMCU_rows = (JDIMENSION) 302 jdiv_round_up((long) cinfo->jpeg_height, 303 (long) (cinfo->max_v_samp_factor*DCTSIZE)); 304} 305 306 307#ifdef C_MULTISCAN_FILES_SUPPORTED 308 309LOCAL(void) 310validate_script (j_compress_ptr cinfo) 311/* Verify that the scan script in cinfo->scan_info[] is valid; also 312 * determine whether it uses progressive JPEG, and set cinfo->progressive_mode. 313 */ 314{ 315 const jpeg_scan_info * scanptr; 316 int scanno, ncomps, ci, coefi, thisi; 317 int Ss, Se, Ah, Al; 318 boolean component_sent[MAX_COMPONENTS]; 319#ifdef C_PROGRESSIVE_SUPPORTED 320 int * last_bitpos_ptr; 321 int last_bitpos[MAX_COMPONENTS][DCTSIZE2]; 322 /* -1 until that coefficient has been seen; then last Al for it */ 323#endif 324 325 if (cinfo->num_scans <= 0) 326 ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, 0); 327 328 /* For sequential JPEG, all scans must have Ss=0, Se=DCTSIZE2-1; 329 * for progressive JPEG, no scan can have this. 330 */ 331 scanptr = cinfo->scan_info; 332 if (scanptr->Ss != 0 || scanptr->Se != DCTSIZE2-1) { 333#ifdef C_PROGRESSIVE_SUPPORTED 334 cinfo->progressive_mode = TRUE; 335 last_bitpos_ptr = & last_bitpos[0][0]; 336 for (ci = 0; ci < cinfo->num_components; ci++) 337 for (coefi = 0; coefi < DCTSIZE2; coefi++) 338 *last_bitpos_ptr++ = -1; 339#else 340 ERREXIT(cinfo, JERR_NOT_COMPILED); 341#endif 342 } else { 343 cinfo->progressive_mode = FALSE; 344 for (ci = 0; ci < cinfo->num_components; ci++) 345 component_sent[ci] = FALSE; 346 } 347 348 for (scanno = 1; scanno <= cinfo->num_scans; scanptr++, scanno++) { 349 /* Validate component indexes */ 350 ncomps = scanptr->comps_in_scan; 351 if (ncomps <= 0 || ncomps > MAX_COMPS_IN_SCAN) 352 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, ncomps, MAX_COMPS_IN_SCAN); 353 for (ci = 0; ci < ncomps; ci++) { 354 thisi = scanptr->component_index[ci]; 355 if (thisi < 0 || thisi >= cinfo->num_components) 356 ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno); 357 /* Components must appear in SOF order within each scan */ 358 if (ci > 0 && thisi <= scanptr->component_index[ci-1]) 359 ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno); 360 } 361 /* Validate progression parameters */ 362 Ss = scanptr->Ss; 363 Se = scanptr->Se; 364 Ah = scanptr->Ah; 365 Al = scanptr->Al; 366 if (cinfo->progressive_mode) { 367#ifdef C_PROGRESSIVE_SUPPORTED 368 /* The JPEG spec simply gives the ranges 0..13 for Ah and Al, but that 369 * seems wrong: the upper bound ought to depend on data precision. 370 * Perhaps they really meant 0..N+1 for N-bit precision. 371 * Here we allow 0..10 for 8-bit data; Al larger than 10 results in 372 * out-of-range reconstructed DC values during the first DC scan, 373 * which might cause problems for some decoders. 374 */ 375#if BITS_IN_JSAMPLE == 8 376#define MAX_AH_AL 10 377#else 378#define MAX_AH_AL 13 379#endif 380 if (Ss < 0 || Ss >= DCTSIZE2 || Se < Ss || Se >= DCTSIZE2 || 381 Ah < 0 || Ah > MAX_AH_AL || Al < 0 || Al > MAX_AH_AL) 382 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno); 383 if (Ss == 0) { 384 if (Se != 0) /* DC and AC together not OK */ 385 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno); 386 } else { 387 if (ncomps != 1) /* AC scans must be for only one component */ 388 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno); 389 } 390 for (ci = 0; ci < ncomps; ci++) { 391 last_bitpos_ptr = & last_bitpos[scanptr->component_index[ci]][0]; 392 if (Ss != 0 && last_bitpos_ptr[0] < 0) /* AC without prior DC scan */ 393 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno); 394 for (coefi = Ss; coefi <= Se; coefi++) { 395 if (last_bitpos_ptr[coefi] < 0) { 396 /* first scan of this coefficient */ 397 if (Ah != 0) 398 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno); 399 } else { 400 /* not first scan */ 401 if (Ah != last_bitpos_ptr[coefi] || Al != Ah-1) 402 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno); 403 } 404 last_bitpos_ptr[coefi] = Al; 405 } 406 } 407#endif 408 } else { 409 /* For sequential JPEG, all progression parameters must be these: */ 410 if (Ss != 0 || Se != DCTSIZE2-1 || Ah != 0 || Al != 0) 411 ERREXIT1(cinfo, JERR_BAD_PROG_SCRIPT, scanno); 412 /* Make sure components are not sent twice */ 413 for (ci = 0; ci < ncomps; ci++) { 414 thisi = scanptr->component_index[ci]; 415 if (component_sent[thisi]) 416 ERREXIT1(cinfo, JERR_BAD_SCAN_SCRIPT, scanno); 417 component_sent[thisi] = TRUE; 418 } 419 } 420 } 421 422 /* Now verify that everything got sent. */ 423 if (cinfo->progressive_mode) { 424#ifdef C_PROGRESSIVE_SUPPORTED 425 /* For progressive mode, we only check that at least some DC data 426 * got sent for each component; the spec does not require that all bits 427 * of all coefficients be transmitted. Would it be wiser to enforce 428 * transmission of all coefficient bits?? 429 */ 430 for (ci = 0; ci < cinfo->num_components; ci++) { 431 if (last_bitpos[ci][0] < 0) 432 ERREXIT(cinfo, JERR_MISSING_DATA); 433 } 434#endif 435 } else { 436 for (ci = 0; ci < cinfo->num_components; ci++) { 437 if (! component_sent[ci]) 438 ERREXIT(cinfo, JERR_MISSING_DATA); 439 } 440 } 441} 442 443#endif /* C_MULTISCAN_FILES_SUPPORTED */ 444 445 446LOCAL(void) 447select_scan_parameters (j_compress_ptr cinfo) 448/* Set up the scan parameters for the current scan */ 449{ 450 int ci; 451 452#ifdef C_MULTISCAN_FILES_SUPPORTED 453 if (cinfo->scan_info != NULL) { 454 /* Prepare for current scan --- the script is already validated */ 455 my_master_ptr master = (my_master_ptr) cinfo->master; 456 const jpeg_scan_info * scanptr = cinfo->scan_info + master->scan_number; 457 458 cinfo->comps_in_scan = scanptr->comps_in_scan; 459 for (ci = 0; ci < scanptr->comps_in_scan; ci++) { 460 cinfo->cur_comp_info[ci] = 461 &cinfo->comp_info[scanptr->component_index[ci]]; 462 } 463 cinfo->Ss = scanptr->Ss; 464 cinfo->Se = scanptr->Se; 465 cinfo->Ah = scanptr->Ah; 466 cinfo->Al = scanptr->Al; 467 } 468 else 469#endif 470 { 471 /* Prepare for single sequential-JPEG scan containing all components */ 472 if (cinfo->num_components > MAX_COMPS_IN_SCAN) 473 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components, 474 MAX_COMPS_IN_SCAN); 475 cinfo->comps_in_scan = cinfo->num_components; 476 for (ci = 0; ci < cinfo->num_components; ci++) { 477 cinfo->cur_comp_info[ci] = &cinfo->comp_info[ci]; 478 } 479 cinfo->Ss = 0; 480 cinfo->Se = DCTSIZE2-1; 481 cinfo->Ah = 0; 482 cinfo->Al = 0; 483 } 484} 485 486 487LOCAL(void) 488per_scan_setup (j_compress_ptr cinfo) 489/* Do computations that are needed before processing a JPEG scan */ 490/* cinfo->comps_in_scan and cinfo->cur_comp_info[] are already set */ 491{ 492 int ci, mcublks, tmp; 493 jpeg_component_info *compptr; 494 495 if (cinfo->comps_in_scan == 1) { 496 497 /* Noninterleaved (single-component) scan */ 498 compptr = cinfo->cur_comp_info[0]; 499 500 /* Overall image size in MCUs */ 501 cinfo->MCUs_per_row = compptr->width_in_blocks; 502 cinfo->MCU_rows_in_scan = compptr->height_in_blocks; 503 504 /* For noninterleaved scan, always one block per MCU */ 505 compptr->MCU_width = 1; 506 compptr->MCU_height = 1; 507 compptr->MCU_blocks = 1; 508 compptr->MCU_sample_width = compptr->DCT_h_scaled_size; 509 compptr->last_col_width = 1; 510 /* For noninterleaved scans, it is convenient to define last_row_height 511 * as the number of block rows present in the last iMCU row. 512 */ 513 tmp = (int) (compptr->height_in_blocks % compptr->v_samp_factor); 514 if (tmp == 0) tmp = compptr->v_samp_factor; 515 compptr->last_row_height = tmp; 516 517 /* Prepare array describing MCU composition */ 518 cinfo->blocks_in_MCU = 1; 519 cinfo->MCU_membership[0] = 0; 520 521 } else { 522 523 /* Interleaved (multi-component) scan */ 524 if (cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN) 525 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan, 526 MAX_COMPS_IN_SCAN); 527 528 /* Overall image size in MCUs */ 529 cinfo->MCUs_per_row = (JDIMENSION) 530 jdiv_round_up((long) cinfo->jpeg_width, 531 (long) (cinfo->max_h_samp_factor*DCTSIZE)); 532 cinfo->MCU_rows_in_scan = (JDIMENSION) 533 jdiv_round_up((long) cinfo->jpeg_height, 534 (long) (cinfo->max_v_samp_factor*DCTSIZE)); 535 536 cinfo->blocks_in_MCU = 0; 537 538 for (ci = 0; ci < cinfo->comps_in_scan; ci++) { 539 compptr = cinfo->cur_comp_info[ci]; 540 /* Sampling factors give # of blocks of component in each MCU */ 541 compptr->MCU_width = compptr->h_samp_factor; 542 compptr->MCU_height = compptr->v_samp_factor; 543 compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height; 544 compptr->MCU_sample_width = compptr->MCU_width * compptr->DCT_h_scaled_size; 545 /* Figure number of non-dummy blocks in last MCU column & row */ 546 tmp = (int) (compptr->width_in_blocks % compptr->MCU_width); 547 if (tmp == 0) tmp = compptr->MCU_width; 548 compptr->last_col_width = tmp; 549 tmp = (int) (compptr->height_in_blocks % compptr->MCU_height); 550 if (tmp == 0) tmp = compptr->MCU_height; 551 compptr->last_row_height = tmp; 552 /* Prepare array describing MCU composition */ 553 mcublks = compptr->MCU_blocks; 554 if (cinfo->blocks_in_MCU + mcublks > C_MAX_BLOCKS_IN_MCU) 555 ERREXIT(cinfo, JERR_BAD_MCU_SIZE); 556 while (mcublks-- > 0) { 557 cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci; 558 } 559 } 560 561 } 562 563 /* Convert restart specified in rows to actual MCU count. */ 564 /* Note that count must fit in 16 bits, so we provide limiting. */ 565 if (cinfo->restart_in_rows > 0) { 566 long nominal = (long) cinfo->restart_in_rows * (long) cinfo->MCUs_per_row; 567 cinfo->restart_interval = (unsigned int) MIN(nominal, 65535L); 568 } 569} 570 571 572/* 573 * Per-pass setup. 574 * This is called at the beginning of each pass. We determine which modules 575 * will be active during this pass and give them appropriate start_pass calls. 576 * We also set is_last_pass to indicate whether any more passes will be 577 * required. 578 */ 579 580METHODDEF(void) 581prepare_for_pass (j_compress_ptr cinfo) 582{ 583 my_master_ptr master = (my_master_ptr) cinfo->master; 584 585 switch (master->pass_type) { 586 case main_pass: 587 /* Initial pass: will collect input data, and do either Huffman 588 * optimization or data output for the first scan. 589 */ 590 select_scan_parameters(cinfo); 591 per_scan_setup(cinfo); 592 if (! cinfo->raw_data_in) { 593 (*cinfo->cconvert->start_pass) (cinfo); 594 (*cinfo->downsample->start_pass) (cinfo); 595 (*cinfo->prep->start_pass) (cinfo, JBUF_PASS_THRU); 596 } 597 (*cinfo->fdct->start_pass) (cinfo); 598 (*cinfo->entropy->start_pass) (cinfo, cinfo->optimize_coding); 599 (*cinfo->coef->start_pass) (cinfo, 600 (master->total_passes > 1 ? 601 JBUF_SAVE_AND_PASS : JBUF_PASS_THRU)); 602 (*cinfo->main->start_pass) (cinfo, JBUF_PASS_THRU); 603 if (cinfo->optimize_coding) { 604 /* No immediate data output; postpone writing frame/scan headers */ 605 master->pub.call_pass_startup = FALSE; 606 } else { 607 /* Will write frame/scan headers at first jpeg_write_scanlines call */ 608 master->pub.call_pass_startup = TRUE; 609 } 610 break; 611#ifdef ENTROPY_OPT_SUPPORTED 612 case huff_opt_pass: 613 /* Do Huffman optimization for a scan after the first one. */ 614 select_scan_parameters(cinfo); 615 per_scan_setup(cinfo); 616 if (cinfo->Ss != 0 || cinfo->Ah == 0) { 617 (*cinfo->entropy->start_pass) (cinfo, TRUE); 618 (*cinfo->coef->start_pass) (cinfo, JBUF_CRANK_DEST); 619 master->pub.call_pass_startup = FALSE; 620 break; 621 } 622 /* Special case: Huffman DC refinement scans need no Huffman table 623 * and therefore we can skip the optimization pass for them. 624 */ 625 master->pass_type = output_pass; 626 master->pass_number++; 627 /*FALLTHROUGH*/ 628#endif 629 case output_pass: 630 /* Do a data-output pass. */ 631 /* We need not repeat per-scan setup if prior optimization pass did it. */ 632 if (! cinfo->optimize_coding) { 633 select_scan_parameters(cinfo); 634 per_scan_setup(cinfo); 635 } 636 (*cinfo->entropy->start_pass) (cinfo, FALSE); 637 (*cinfo->coef->start_pass) (cinfo, JBUF_CRANK_DEST); 638 /* We emit frame/scan headers now */ 639 if (master->scan_number == 0) 640 (*cinfo->marker->write_frame_header) (cinfo); 641 (*cinfo->marker->write_scan_header) (cinfo); 642 master->pub.call_pass_startup = FALSE; 643 break; 644 default: 645 ERREXIT(cinfo, JERR_NOT_COMPILED); 646 } 647 648 master->pub.is_last_pass = (master->pass_number == master->total_passes-1); 649 650 /* Set up progress monitor's pass info if present */ 651 if (cinfo->progress != NULL) { 652 cinfo->progress->completed_passes = master->pass_number; 653 cinfo->progress->total_passes = master->total_passes; 654 } 655} 656 657 658/* 659 * Special start-of-pass hook. 660 * This is called by jpeg_write_scanlines if call_pass_startup is TRUE. 661 * In single-pass processing, we need this hook because we don't want to 662 * write frame/scan headers during jpeg_start_compress; we want to let the 663 * application write COM markers etc. between jpeg_start_compress and the 664 * jpeg_write_scanlines loop. 665 * In multi-pass processing, this routine is not used. 666 */ 667 668METHODDEF(void) 669pass_startup (j_compress_ptr cinfo) 670{ 671 cinfo->master->call_pass_startup = FALSE; /* reset flag so call only once */ 672 673 (*cinfo->marker->write_frame_header) (cinfo); 674 (*cinfo->marker->write_scan_header) (cinfo); 675} 676 677 678/* 679 * Finish up at end of pass. 680 */ 681 682METHODDEF(void) 683finish_pass_master (j_compress_ptr cinfo) 684{ 685 my_master_ptr master = (my_master_ptr) cinfo->master; 686 687 /* The entropy coder always needs an end-of-pass call, 688 * either to analyze statistics or to flush its output buffer. 689 */ 690 (*cinfo->entropy->finish_pass) (cinfo); 691 692 /* Update state for next pass */ 693 switch (master->pass_type) { 694 case main_pass: 695 /* next pass is either output of scan 0 (after optimization) 696 * or output of scan 1 (if no optimization). 697 */ 698 master->pass_type = output_pass; 699 if (! cinfo->optimize_coding) 700 master->scan_number++; 701 break; 702 case huff_opt_pass: 703 /* next pass is always output of current scan */ 704 master->pass_type = output_pass; 705 break; 706 case output_pass: 707 /* next pass is either optimization or output of next scan */ 708 if (cinfo->optimize_coding) 709 master->pass_type = huff_opt_pass; 710 master->scan_number++; 711 break; 712 } 713 714 master->pass_number++; 715} 716 717 718/* 719 * Initialize master compression control. 720 */ 721 722GLOBAL(void) 723jinit_c_master_control (j_compress_ptr cinfo, boolean transcode_only) 724{ 725 my_master_ptr master; 726 727 master = (my_master_ptr) 728 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 729 SIZEOF(my_comp_master)); 730 cinfo->master = (struct jpeg_comp_master *) master; 731 master->pub.prepare_for_pass = prepare_for_pass; 732 master->pub.pass_startup = pass_startup; 733 master->pub.finish_pass = finish_pass_master; 734 master->pub.is_last_pass = FALSE; 735 736 /* Validate parameters, determine derived values */ 737 initial_setup(cinfo); 738 739 if (cinfo->scan_info != NULL) { 740#ifdef C_MULTISCAN_FILES_SUPPORTED 741 validate_script(cinfo); 742#else 743 ERREXIT(cinfo, JERR_NOT_COMPILED); 744#endif 745 } else { 746 cinfo->progressive_mode = FALSE; 747 cinfo->num_scans = 1; 748 } 749 750 if (cinfo->progressive_mode && cinfo->arith_code == 0) /* TEMPORARY HACK ??? */ 751 cinfo->optimize_coding = TRUE; /* assume default tables no good for progressive mode */ 752 753 /* Initialize my private state */ 754 if (transcode_only) { 755 /* no main pass in transcoding */ 756 if (cinfo->optimize_coding) 757 master->pass_type = huff_opt_pass; 758 else 759 master->pass_type = output_pass; 760 } else { 761 /* for normal compression, first pass is always this type: */ 762 master->pass_type = main_pass; 763 } 764 master->scan_number = 0; 765 master->pass_number = 0; 766 if (cinfo->optimize_coding) 767 master->total_passes = cinfo->num_scans * 2; 768 else 769 master->total_passes = cinfo->num_scans; 770} 771