1/* 2 * jdinput.c 3 * 4 * Copyright (C) 1991-1997, Thomas G. Lane. 5 * Modified 2002-2009 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 input control logic for the JPEG decompressor. 10 * These routines are concerned with controlling the decompressor's input 11 * processing (marker reading and coefficient decoding). The actual input 12 * reading is done in jdmarker.c, jdhuff.c, and jdarith.c. 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_input_controller pub; /* public fields */ 24 25 int inheaders; /* Nonzero until first SOS is reached */ 26} my_input_controller; 27 28typedef my_input_controller * my_inputctl_ptr; 29 30 31/* Forward declarations */ 32METHODDEF(int) consume_markers JPP((j_decompress_ptr cinfo)); 33 34 35/* 36 * Routines to calculate various quantities related to the size of the image. 37 */ 38 39 40/* 41 * Compute output image dimensions and related values. 42 * NOTE: this is exported for possible use by application. 43 * Hence it mustn't do anything that can't be done twice. 44 */ 45 46GLOBAL(void) 47jpeg_core_output_dimensions (j_decompress_ptr cinfo) 48/* Do computations that are needed before master selection phase. 49 * This function is used for transcoding and full decompression. 50 */ 51{ 52#ifdef IDCT_SCALING_SUPPORTED 53 int ci; 54 jpeg_component_info *compptr; 55 56 /* Compute actual output image dimensions and DCT scaling choices. */ 57 if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom) { 58 /* Provide 1/block_size scaling */ 59 cinfo->output_width = (JDIMENSION) 60 jdiv_round_up((long) cinfo->image_width, (long) cinfo->block_size); 61 cinfo->output_height = (JDIMENSION) 62 jdiv_round_up((long) cinfo->image_height, (long) cinfo->block_size); 63 cinfo->min_DCT_h_scaled_size = 1; 64 cinfo->min_DCT_v_scaled_size = 1; 65 } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 2) { 66 /* Provide 2/block_size scaling */ 67 cinfo->output_width = (JDIMENSION) 68 jdiv_round_up((long) cinfo->image_width * 2L, (long) cinfo->block_size); 69 cinfo->output_height = (JDIMENSION) 70 jdiv_round_up((long) cinfo->image_height * 2L, (long) cinfo->block_size); 71 cinfo->min_DCT_h_scaled_size = 2; 72 cinfo->min_DCT_v_scaled_size = 2; 73 } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 3) { 74 /* Provide 3/block_size scaling */ 75 cinfo->output_width = (JDIMENSION) 76 jdiv_round_up((long) cinfo->image_width * 3L, (long) cinfo->block_size); 77 cinfo->output_height = (JDIMENSION) 78 jdiv_round_up((long) cinfo->image_height * 3L, (long) cinfo->block_size); 79 cinfo->min_DCT_h_scaled_size = 3; 80 cinfo->min_DCT_v_scaled_size = 3; 81 } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 4) { 82 /* Provide 4/block_size scaling */ 83 cinfo->output_width = (JDIMENSION) 84 jdiv_round_up((long) cinfo->image_width * 4L, (long) cinfo->block_size); 85 cinfo->output_height = (JDIMENSION) 86 jdiv_round_up((long) cinfo->image_height * 4L, (long) cinfo->block_size); 87 cinfo->min_DCT_h_scaled_size = 4; 88 cinfo->min_DCT_v_scaled_size = 4; 89 } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 5) { 90 /* Provide 5/block_size scaling */ 91 cinfo->output_width = (JDIMENSION) 92 jdiv_round_up((long) cinfo->image_width * 5L, (long) cinfo->block_size); 93 cinfo->output_height = (JDIMENSION) 94 jdiv_round_up((long) cinfo->image_height * 5L, (long) cinfo->block_size); 95 cinfo->min_DCT_h_scaled_size = 5; 96 cinfo->min_DCT_v_scaled_size = 5; 97 } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 6) { 98 /* Provide 6/block_size scaling */ 99 cinfo->output_width = (JDIMENSION) 100 jdiv_round_up((long) cinfo->image_width * 6L, (long) cinfo->block_size); 101 cinfo->output_height = (JDIMENSION) 102 jdiv_round_up((long) cinfo->image_height * 6L, (long) cinfo->block_size); 103 cinfo->min_DCT_h_scaled_size = 6; 104 cinfo->min_DCT_v_scaled_size = 6; 105 } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 7) { 106 /* Provide 7/block_size scaling */ 107 cinfo->output_width = (JDIMENSION) 108 jdiv_round_up((long) cinfo->image_width * 7L, (long) cinfo->block_size); 109 cinfo->output_height = (JDIMENSION) 110 jdiv_round_up((long) cinfo->image_height * 7L, (long) cinfo->block_size); 111 cinfo->min_DCT_h_scaled_size = 7; 112 cinfo->min_DCT_v_scaled_size = 7; 113 } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 8) { 114 /* Provide 8/block_size scaling */ 115 cinfo->output_width = (JDIMENSION) 116 jdiv_round_up((long) cinfo->image_width * 8L, (long) cinfo->block_size); 117 cinfo->output_height = (JDIMENSION) 118 jdiv_round_up((long) cinfo->image_height * 8L, (long) cinfo->block_size); 119 cinfo->min_DCT_h_scaled_size = 8; 120 cinfo->min_DCT_v_scaled_size = 8; 121 } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 9) { 122 /* Provide 9/block_size scaling */ 123 cinfo->output_width = (JDIMENSION) 124 jdiv_round_up((long) cinfo->image_width * 9L, (long) cinfo->block_size); 125 cinfo->output_height = (JDIMENSION) 126 jdiv_round_up((long) cinfo->image_height * 9L, (long) cinfo->block_size); 127 cinfo->min_DCT_h_scaled_size = 9; 128 cinfo->min_DCT_v_scaled_size = 9; 129 } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 10) { 130 /* Provide 10/block_size scaling */ 131 cinfo->output_width = (JDIMENSION) 132 jdiv_round_up((long) cinfo->image_width * 10L, (long) cinfo->block_size); 133 cinfo->output_height = (JDIMENSION) 134 jdiv_round_up((long) cinfo->image_height * 10L, (long) cinfo->block_size); 135 cinfo->min_DCT_h_scaled_size = 10; 136 cinfo->min_DCT_v_scaled_size = 10; 137 } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 11) { 138 /* Provide 11/block_size scaling */ 139 cinfo->output_width = (JDIMENSION) 140 jdiv_round_up((long) cinfo->image_width * 11L, (long) cinfo->block_size); 141 cinfo->output_height = (JDIMENSION) 142 jdiv_round_up((long) cinfo->image_height * 11L, (long) cinfo->block_size); 143 cinfo->min_DCT_h_scaled_size = 11; 144 cinfo->min_DCT_v_scaled_size = 11; 145 } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 12) { 146 /* Provide 12/block_size scaling */ 147 cinfo->output_width = (JDIMENSION) 148 jdiv_round_up((long) cinfo->image_width * 12L, (long) cinfo->block_size); 149 cinfo->output_height = (JDIMENSION) 150 jdiv_round_up((long) cinfo->image_height * 12L, (long) cinfo->block_size); 151 cinfo->min_DCT_h_scaled_size = 12; 152 cinfo->min_DCT_v_scaled_size = 12; 153 } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 13) { 154 /* Provide 13/block_size scaling */ 155 cinfo->output_width = (JDIMENSION) 156 jdiv_round_up((long) cinfo->image_width * 13L, (long) cinfo->block_size); 157 cinfo->output_height = (JDIMENSION) 158 jdiv_round_up((long) cinfo->image_height * 13L, (long) cinfo->block_size); 159 cinfo->min_DCT_h_scaled_size = 13; 160 cinfo->min_DCT_v_scaled_size = 13; 161 } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 14) { 162 /* Provide 14/block_size scaling */ 163 cinfo->output_width = (JDIMENSION) 164 jdiv_round_up((long) cinfo->image_width * 14L, (long) cinfo->block_size); 165 cinfo->output_height = (JDIMENSION) 166 jdiv_round_up((long) cinfo->image_height * 14L, (long) cinfo->block_size); 167 cinfo->min_DCT_h_scaled_size = 14; 168 cinfo->min_DCT_v_scaled_size = 14; 169 } else if (cinfo->scale_num * cinfo->block_size <= cinfo->scale_denom * 15) { 170 /* Provide 15/block_size scaling */ 171 cinfo->output_width = (JDIMENSION) 172 jdiv_round_up((long) cinfo->image_width * 15L, (long) cinfo->block_size); 173 cinfo->output_height = (JDIMENSION) 174 jdiv_round_up((long) cinfo->image_height * 15L, (long) cinfo->block_size); 175 cinfo->min_DCT_h_scaled_size = 15; 176 cinfo->min_DCT_v_scaled_size = 15; 177 } else { 178 /* Provide 16/block_size scaling */ 179 cinfo->output_width = (JDIMENSION) 180 jdiv_round_up((long) cinfo->image_width * 16L, (long) cinfo->block_size); 181 cinfo->output_height = (JDIMENSION) 182 jdiv_round_up((long) cinfo->image_height * 16L, (long) cinfo->block_size); 183 cinfo->min_DCT_h_scaled_size = 16; 184 cinfo->min_DCT_v_scaled_size = 16; 185 } 186 187 /* Recompute dimensions of components */ 188 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 189 ci++, compptr++) { 190 compptr->DCT_h_scaled_size = cinfo->min_DCT_h_scaled_size; 191 compptr->DCT_v_scaled_size = cinfo->min_DCT_v_scaled_size; 192 } 193 194#else /* !IDCT_SCALING_SUPPORTED */ 195 196 /* Hardwire it to "no scaling" */ 197 cinfo->output_width = cinfo->image_width; 198 cinfo->output_height = cinfo->image_height; 199 /* jdinput.c has already initialized DCT_scaled_size, 200 * and has computed unscaled downsampled_width and downsampled_height. 201 */ 202 203#endif /* IDCT_SCALING_SUPPORTED */ 204} 205 206 207LOCAL(void) 208initial_setup (j_decompress_ptr cinfo) 209/* Called once, when first SOS marker is reached */ 210{ 211 int ci; 212 jpeg_component_info *compptr; 213 214 /* Make sure image isn't bigger than I can handle */ 215 if ((long) cinfo->image_height > (long) JPEG_MAX_DIMENSION || 216 (long) cinfo->image_width > (long) JPEG_MAX_DIMENSION) 217 ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION); 218 219 /* For now, precision must match compiled-in value... */ 220 if (cinfo->data_precision != BITS_IN_JSAMPLE) 221 ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision); 222 223 /* Check that number of components won't exceed internal array sizes */ 224 if (cinfo->num_components > MAX_COMPONENTS) 225 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->num_components, 226 MAX_COMPONENTS); 227 228 /* Compute maximum sampling factors; check factor validity */ 229 cinfo->max_h_samp_factor = 1; 230 cinfo->max_v_samp_factor = 1; 231 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 232 ci++, compptr++) { 233 if (compptr->h_samp_factor<=0 || compptr->h_samp_factor>MAX_SAMP_FACTOR || 234 compptr->v_samp_factor<=0 || compptr->v_samp_factor>MAX_SAMP_FACTOR) 235 ERREXIT(cinfo, JERR_BAD_SAMPLING); 236 cinfo->max_h_samp_factor = MAX(cinfo->max_h_samp_factor, 237 compptr->h_samp_factor); 238 cinfo->max_v_samp_factor = MAX(cinfo->max_v_samp_factor, 239 compptr->v_samp_factor); 240 } 241 242 /* Derive block_size, natural_order, and lim_Se */ 243 if (cinfo->is_baseline || (cinfo->progressive_mode && 244 cinfo->comps_in_scan)) { /* no pseudo SOS marker */ 245 cinfo->block_size = DCTSIZE; 246 cinfo->natural_order = jpeg_natural_order; 247 cinfo->lim_Se = DCTSIZE2-1; 248 } else 249 switch (cinfo->Se) { 250 case (1*1-1): 251 cinfo->block_size = 1; 252 cinfo->natural_order = jpeg_natural_order; /* not needed */ 253 cinfo->lim_Se = cinfo->Se; 254 break; 255 case (2*2-1): 256 cinfo->block_size = 2; 257 cinfo->natural_order = jpeg_natural_order2; 258 cinfo->lim_Se = cinfo->Se; 259 break; 260 case (3*3-1): 261 cinfo->block_size = 3; 262 cinfo->natural_order = jpeg_natural_order3; 263 cinfo->lim_Se = cinfo->Se; 264 break; 265 case (4*4-1): 266 cinfo->block_size = 4; 267 cinfo->natural_order = jpeg_natural_order4; 268 cinfo->lim_Se = cinfo->Se; 269 break; 270 case (5*5-1): 271 cinfo->block_size = 5; 272 cinfo->natural_order = jpeg_natural_order5; 273 cinfo->lim_Se = cinfo->Se; 274 break; 275 case (6*6-1): 276 cinfo->block_size = 6; 277 cinfo->natural_order = jpeg_natural_order6; 278 cinfo->lim_Se = cinfo->Se; 279 break; 280 case (7*7-1): 281 cinfo->block_size = 7; 282 cinfo->natural_order = jpeg_natural_order7; 283 cinfo->lim_Se = cinfo->Se; 284 break; 285 case (8*8-1): 286 cinfo->block_size = 8; 287 cinfo->natural_order = jpeg_natural_order; 288 cinfo->lim_Se = DCTSIZE2-1; 289 break; 290 case (9*9-1): 291 cinfo->block_size = 9; 292 cinfo->natural_order = jpeg_natural_order; 293 cinfo->lim_Se = DCTSIZE2-1; 294 break; 295 case (10*10-1): 296 cinfo->block_size = 10; 297 cinfo->natural_order = jpeg_natural_order; 298 cinfo->lim_Se = DCTSIZE2-1; 299 break; 300 case (11*11-1): 301 cinfo->block_size = 11; 302 cinfo->natural_order = jpeg_natural_order; 303 cinfo->lim_Se = DCTSIZE2-1; 304 break; 305 case (12*12-1): 306 cinfo->block_size = 12; 307 cinfo->natural_order = jpeg_natural_order; 308 cinfo->lim_Se = DCTSIZE2-1; 309 break; 310 case (13*13-1): 311 cinfo->block_size = 13; 312 cinfo->natural_order = jpeg_natural_order; 313 cinfo->lim_Se = DCTSIZE2-1; 314 break; 315 case (14*14-1): 316 cinfo->block_size = 14; 317 cinfo->natural_order = jpeg_natural_order; 318 cinfo->lim_Se = DCTSIZE2-1; 319 break; 320 case (15*15-1): 321 cinfo->block_size = 15; 322 cinfo->natural_order = jpeg_natural_order; 323 cinfo->lim_Se = DCTSIZE2-1; 324 break; 325 case (16*16-1): 326 cinfo->block_size = 16; 327 cinfo->natural_order = jpeg_natural_order; 328 cinfo->lim_Se = DCTSIZE2-1; 329 break; 330 default: 331 ERREXIT4(cinfo, JERR_BAD_PROGRESSION, 332 cinfo->Ss, cinfo->Se, cinfo->Ah, cinfo->Al); 333 break; 334 } 335 336 /* We initialize DCT_scaled_size and min_DCT_scaled_size to block_size. 337 * In the full decompressor, 338 * this will be overridden by jpeg_calc_output_dimensions in jdmaster.c; 339 * but in the transcoder, 340 * jpeg_calc_output_dimensions is not used, so we must do it here. 341 */ 342 cinfo->min_DCT_h_scaled_size = cinfo->block_size; 343 cinfo->min_DCT_v_scaled_size = cinfo->block_size; 344 345 /* Compute dimensions of components */ 346 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 347 ci++, compptr++) { 348 compptr->DCT_h_scaled_size = cinfo->block_size; 349 compptr->DCT_v_scaled_size = cinfo->block_size; 350 /* Size in DCT blocks */ 351 compptr->width_in_blocks = (JDIMENSION) 352 jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor, 353 (long) (cinfo->max_h_samp_factor * cinfo->block_size)); 354 compptr->height_in_blocks = (JDIMENSION) 355 jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor, 356 (long) (cinfo->max_v_samp_factor * cinfo->block_size)); 357 /* downsampled_width and downsampled_height will also be overridden by 358 * jdmaster.c if we are doing full decompression. The transcoder library 359 * doesn't use these values, but the calling application might. 360 */ 361 /* Size in samples */ 362 compptr->downsampled_width = (JDIMENSION) 363 jdiv_round_up((long) cinfo->image_width * (long) compptr->h_samp_factor, 364 (long) cinfo->max_h_samp_factor); 365 compptr->downsampled_height = (JDIMENSION) 366 jdiv_round_up((long) cinfo->image_height * (long) compptr->v_samp_factor, 367 (long) cinfo->max_v_samp_factor); 368 /* Mark component needed, until color conversion says otherwise */ 369 compptr->component_needed = TRUE; 370 /* Mark no quantization table yet saved for component */ 371 compptr->quant_table = NULL; 372 } 373 374 /* Compute number of fully interleaved MCU rows. */ 375 cinfo->total_iMCU_rows = (JDIMENSION) 376 jdiv_round_up((long) cinfo->image_height, 377 (long) (cinfo->max_v_samp_factor * cinfo->block_size)); 378 379 /* Decide whether file contains multiple scans */ 380 if (cinfo->comps_in_scan < cinfo->num_components || cinfo->progressive_mode) 381 cinfo->inputctl->has_multiple_scans = TRUE; 382 else 383 cinfo->inputctl->has_multiple_scans = FALSE; 384} 385 386 387LOCAL(void) 388per_scan_setup (j_decompress_ptr cinfo) 389/* Do computations that are needed before processing a JPEG scan */ 390/* cinfo->comps_in_scan and cinfo->cur_comp_info[] were set from SOS marker */ 391{ 392 int ci, mcublks, tmp; 393 jpeg_component_info *compptr; 394 395 if (cinfo->comps_in_scan == 1) { 396 397 /* Noninterleaved (single-component) scan */ 398 compptr = cinfo->cur_comp_info[0]; 399 400 /* Overall image size in MCUs */ 401 cinfo->MCUs_per_row = compptr->width_in_blocks; 402 cinfo->MCU_rows_in_scan = compptr->height_in_blocks; 403 404 /* For noninterleaved scan, always one block per MCU */ 405 compptr->MCU_width = 1; 406 compptr->MCU_height = 1; 407 compptr->MCU_blocks = 1; 408 compptr->MCU_sample_width = compptr->DCT_h_scaled_size; 409 compptr->last_col_width = 1; 410 /* For noninterleaved scans, it is convenient to define last_row_height 411 * as the number of block rows present in the last iMCU row. 412 */ 413 tmp = (int) (compptr->height_in_blocks % compptr->v_samp_factor); 414 if (tmp == 0) tmp = compptr->v_samp_factor; 415 compptr->last_row_height = tmp; 416 417 /* Prepare array describing MCU composition */ 418 cinfo->blocks_in_MCU = 1; 419 cinfo->MCU_membership[0] = 0; 420 421 } else { 422 423 /* Interleaved (multi-component) scan */ 424 if (cinfo->comps_in_scan <= 0 || cinfo->comps_in_scan > MAX_COMPS_IN_SCAN) 425 ERREXIT2(cinfo, JERR_COMPONENT_COUNT, cinfo->comps_in_scan, 426 MAX_COMPS_IN_SCAN); 427 428 /* Overall image size in MCUs */ 429 cinfo->MCUs_per_row = (JDIMENSION) 430 jdiv_round_up((long) cinfo->image_width, 431 (long) (cinfo->max_h_samp_factor * cinfo->block_size)); 432 cinfo->MCU_rows_in_scan = (JDIMENSION) 433 jdiv_round_up((long) cinfo->image_height, 434 (long) (cinfo->max_v_samp_factor * cinfo->block_size)); 435 436 cinfo->blocks_in_MCU = 0; 437 438 for (ci = 0; ci < cinfo->comps_in_scan; ci++) { 439 compptr = cinfo->cur_comp_info[ci]; 440 /* Sampling factors give # of blocks of component in each MCU */ 441 compptr->MCU_width = compptr->h_samp_factor; 442 compptr->MCU_height = compptr->v_samp_factor; 443 compptr->MCU_blocks = compptr->MCU_width * compptr->MCU_height; 444 compptr->MCU_sample_width = compptr->MCU_width * compptr->DCT_h_scaled_size; 445 /* Figure number of non-dummy blocks in last MCU column & row */ 446 tmp = (int) (compptr->width_in_blocks % compptr->MCU_width); 447 if (tmp == 0) tmp = compptr->MCU_width; 448 compptr->last_col_width = tmp; 449 tmp = (int) (compptr->height_in_blocks % compptr->MCU_height); 450 if (tmp == 0) tmp = compptr->MCU_height; 451 compptr->last_row_height = tmp; 452 /* Prepare array describing MCU composition */ 453 mcublks = compptr->MCU_blocks; 454 if (cinfo->blocks_in_MCU + mcublks > D_MAX_BLOCKS_IN_MCU) 455 ERREXIT(cinfo, JERR_BAD_MCU_SIZE); 456 while (mcublks-- > 0) { 457 cinfo->MCU_membership[cinfo->blocks_in_MCU++] = ci; 458 } 459 } 460 461 } 462} 463 464 465/* 466 * Save away a copy of the Q-table referenced by each component present 467 * in the current scan, unless already saved during a prior scan. 468 * 469 * In a multiple-scan JPEG file, the encoder could assign different components 470 * the same Q-table slot number, but change table definitions between scans 471 * so that each component uses a different Q-table. (The IJG encoder is not 472 * currently capable of doing this, but other encoders might.) Since we want 473 * to be able to dequantize all the components at the end of the file, this 474 * means that we have to save away the table actually used for each component. 475 * We do this by copying the table at the start of the first scan containing 476 * the component. 477 * The JPEG spec prohibits the encoder from changing the contents of a Q-table 478 * slot between scans of a component using that slot. If the encoder does so 479 * anyway, this decoder will simply use the Q-table values that were current 480 * at the start of the first scan for the component. 481 * 482 * The decompressor output side looks only at the saved quant tables, 483 * not at the current Q-table slots. 484 */ 485 486LOCAL(void) 487latch_quant_tables (j_decompress_ptr cinfo) 488{ 489 int ci, qtblno; 490 jpeg_component_info *compptr; 491 JQUANT_TBL * qtbl; 492 493 for (ci = 0; ci < cinfo->comps_in_scan; ci++) { 494 compptr = cinfo->cur_comp_info[ci]; 495 /* No work if we already saved Q-table for this component */ 496 if (compptr->quant_table != NULL) 497 continue; 498 /* Make sure specified quantization table is present */ 499 qtblno = compptr->quant_tbl_no; 500 if (qtblno < 0 || qtblno >= NUM_QUANT_TBLS || 501 cinfo->quant_tbl_ptrs[qtblno] == NULL) 502 ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, qtblno); 503 /* OK, save away the quantization table */ 504 qtbl = (JQUANT_TBL *) 505 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 506 SIZEOF(JQUANT_TBL)); 507 MEMCOPY(qtbl, cinfo->quant_tbl_ptrs[qtblno], SIZEOF(JQUANT_TBL)); 508 compptr->quant_table = qtbl; 509 } 510} 511 512 513/* 514 * Initialize the input modules to read a scan of compressed data. 515 * The first call to this is done by jdmaster.c after initializing 516 * the entire decompressor (during jpeg_start_decompress). 517 * Subsequent calls come from consume_markers, below. 518 */ 519 520METHODDEF(void) 521start_input_pass (j_decompress_ptr cinfo) 522{ 523 per_scan_setup(cinfo); 524 latch_quant_tables(cinfo); 525 (*cinfo->entropy->start_pass) (cinfo); 526 (*cinfo->coef->start_input_pass) (cinfo); 527 cinfo->inputctl->consume_input = cinfo->coef->consume_data; 528} 529 530 531/* 532 * Finish up after inputting a compressed-data scan. 533 * This is called by the coefficient controller after it's read all 534 * the expected data of the scan. 535 */ 536 537METHODDEF(void) 538finish_input_pass (j_decompress_ptr cinfo) 539{ 540 cinfo->inputctl->consume_input = consume_markers; 541} 542 543 544/* 545 * Read JPEG markers before, between, or after compressed-data scans. 546 * Change state as necessary when a new scan is reached. 547 * Return value is JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI. 548 * 549 * The consume_input method pointer points either here or to the 550 * coefficient controller's consume_data routine, depending on whether 551 * we are reading a compressed data segment or inter-segment markers. 552 * 553 * Note: This function should NOT return a pseudo SOS marker (with zero 554 * component number) to the caller. A pseudo marker received by 555 * read_markers is processed and then skipped for other markers. 556 */ 557 558METHODDEF(int) 559consume_markers (j_decompress_ptr cinfo) 560{ 561 my_inputctl_ptr inputctl = (my_inputctl_ptr) cinfo->inputctl; 562 int val; 563 564 if (inputctl->pub.eoi_reached) /* After hitting EOI, read no further */ 565 return JPEG_REACHED_EOI; 566 567 for (;;) { /* Loop to pass pseudo SOS marker */ 568 val = (*cinfo->marker->read_markers) (cinfo); 569 570 switch (val) { 571 case JPEG_REACHED_SOS: /* Found SOS */ 572 if (inputctl->inheaders) { /* 1st SOS */ 573 if (inputctl->inheaders == 1) 574 initial_setup(cinfo); 575 if (cinfo->comps_in_scan == 0) { /* pseudo SOS marker */ 576 inputctl->inheaders = 2; 577 break; 578 } 579 inputctl->inheaders = 0; 580 /* Note: start_input_pass must be called by jdmaster.c 581 * before any more input can be consumed. jdapimin.c is 582 * responsible for enforcing this sequencing. 583 */ 584 } else { /* 2nd or later SOS marker */ 585 if (! inputctl->pub.has_multiple_scans) 586 ERREXIT(cinfo, JERR_EOI_EXPECTED); /* Oops, I wasn't expecting this! */ 587 if (cinfo->comps_in_scan == 0) /* unexpected pseudo SOS marker */ 588 break; 589 start_input_pass(cinfo); 590 } 591 return val; 592 case JPEG_REACHED_EOI: /* Found EOI */ 593 inputctl->pub.eoi_reached = TRUE; 594 if (inputctl->inheaders) { /* Tables-only datastream, apparently */ 595 if (cinfo->marker->saw_SOF) 596 ERREXIT(cinfo, JERR_SOF_NO_SOS); 597 } else { 598 /* Prevent infinite loop in coef ctlr's decompress_data routine 599 * if user set output_scan_number larger than number of scans. 600 */ 601 if (cinfo->output_scan_number > cinfo->input_scan_number) 602 cinfo->output_scan_number = cinfo->input_scan_number; 603 } 604 return val; 605 case JPEG_SUSPENDED: 606 return val; 607 default: 608 return val; 609 } 610 } 611} 612 613 614/* 615 * Reset state to begin a fresh datastream. 616 */ 617 618METHODDEF(void) 619reset_input_controller (j_decompress_ptr cinfo) 620{ 621 my_inputctl_ptr inputctl = (my_inputctl_ptr) cinfo->inputctl; 622 623 inputctl->pub.consume_input = consume_markers; 624 inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */ 625 inputctl->pub.eoi_reached = FALSE; 626 inputctl->inheaders = 1; 627 /* Reset other modules */ 628 (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo); 629 (*cinfo->marker->reset_marker_reader) (cinfo); 630 /* Reset progression state -- would be cleaner if entropy decoder did this */ 631 cinfo->coef_bits = NULL; 632} 633 634 635/* 636 * Initialize the input controller module. 637 * This is called only once, when the decompression object is created. 638 */ 639 640GLOBAL(void) 641jinit_input_controller (j_decompress_ptr cinfo) 642{ 643 my_inputctl_ptr inputctl; 644 645 /* Create subobject in permanent pool */ 646 inputctl = (my_inputctl_ptr) 647 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT, 648 SIZEOF(my_input_controller)); 649 cinfo->inputctl = (struct jpeg_input_controller *) inputctl; 650 /* Initialize method pointers */ 651 inputctl->pub.consume_input = consume_markers; 652 inputctl->pub.reset_input_controller = reset_input_controller; 653 inputctl->pub.start_input_pass = start_input_pass; 654 inputctl->pub.finish_input_pass = finish_input_pass; 655 /* Initialize state: can't use reset_input_controller since we don't 656 * want to try to reset other modules yet. 657 */ 658 inputctl->pub.has_multiple_scans = FALSE; /* "unknown" would be better */ 659 inputctl->pub.eoi_reached = FALSE; 660 inputctl->inheaders = 1; 661} 662