1/* 2 * jdmarker.c 3 * 4 * Copyright (C) 1991-1998, Thomas G. Lane. 5 * Modified 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 routines to decode JPEG datastream markers. 10 * Most of the complexity arises from our desire to support input 11 * suspension: if not all of the data for a marker is available, 12 * we must exit back to the application. On resumption, we reprocess 13 * the marker. 14 */ 15 16#define JPEG_INTERNALS 17#include "jinclude.h" 18#include "jpeglib.h" 19 20 21typedef enum { /* JPEG marker codes */ 22 M_SOF0 = 0xc0, 23 M_SOF1 = 0xc1, 24 M_SOF2 = 0xc2, 25 M_SOF3 = 0xc3, 26 27 M_SOF5 = 0xc5, 28 M_SOF6 = 0xc6, 29 M_SOF7 = 0xc7, 30 31 M_JPG = 0xc8, 32 M_SOF9 = 0xc9, 33 M_SOF10 = 0xca, 34 M_SOF11 = 0xcb, 35 36 M_SOF13 = 0xcd, 37 M_SOF14 = 0xce, 38 M_SOF15 = 0xcf, 39 40 M_DHT = 0xc4, 41 42 M_DAC = 0xcc, 43 44 M_RST0 = 0xd0, 45 M_RST1 = 0xd1, 46 M_RST2 = 0xd2, 47 M_RST3 = 0xd3, 48 M_RST4 = 0xd4, 49 M_RST5 = 0xd5, 50 M_RST6 = 0xd6, 51 M_RST7 = 0xd7, 52 53 M_SOI = 0xd8, 54 M_EOI = 0xd9, 55 M_SOS = 0xda, 56 M_DQT = 0xdb, 57 M_DNL = 0xdc, 58 M_DRI = 0xdd, 59 M_DHP = 0xde, 60 M_EXP = 0xdf, 61 62 M_APP0 = 0xe0, 63 M_APP1 = 0xe1, 64 M_APP2 = 0xe2, 65 M_APP3 = 0xe3, 66 M_APP4 = 0xe4, 67 M_APP5 = 0xe5, 68 M_APP6 = 0xe6, 69 M_APP7 = 0xe7, 70 M_APP8 = 0xe8, 71 M_APP9 = 0xe9, 72 M_APP10 = 0xea, 73 M_APP11 = 0xeb, 74 M_APP12 = 0xec, 75 M_APP13 = 0xed, 76 M_APP14 = 0xee, 77 M_APP15 = 0xef, 78 79 M_JPG0 = 0xf0, 80 M_JPG13 = 0xfd, 81 M_COM = 0xfe, 82 83 M_TEM = 0x01, 84 85 M_ERROR = 0x100 86} JPEG_MARKER; 87 88 89/* Private state */ 90 91typedef struct { 92 struct jpeg_marker_reader pub; /* public fields */ 93 94 /* Application-overridable marker processing methods */ 95 jpeg_marker_parser_method process_COM; 96 jpeg_marker_parser_method process_APPn[16]; 97 98 /* Limit on marker data length to save for each marker type */ 99 unsigned int length_limit_COM; 100 unsigned int length_limit_APPn[16]; 101 102 /* Status of COM/APPn marker saving */ 103 jpeg_saved_marker_ptr cur_marker; /* NULL if not processing a marker */ 104 unsigned int bytes_read; /* data bytes read so far in marker */ 105 /* Note: cur_marker is not linked into marker_list until it's all read. */ 106} my_marker_reader; 107 108typedef my_marker_reader * my_marker_ptr; 109 110 111/* 112 * Macros for fetching data from the data source module. 113 * 114 * At all times, cinfo->src->next_input_byte and ->bytes_in_buffer reflect 115 * the current restart point; we update them only when we have reached a 116 * suitable place to restart if a suspension occurs. 117 */ 118 119/* Declare and initialize local copies of input pointer/count */ 120#define INPUT_VARS(cinfo) \ 121 struct jpeg_source_mgr * datasrc = (cinfo)->src; \ 122 const JOCTET * next_input_byte = datasrc->next_input_byte; \ 123 size_t bytes_in_buffer = datasrc->bytes_in_buffer 124 125/* Unload the local copies --- do this only at a restart boundary */ 126#define INPUT_SYNC(cinfo) \ 127 ( datasrc->next_input_byte = next_input_byte, \ 128 datasrc->bytes_in_buffer = bytes_in_buffer ) 129 130/* Reload the local copies --- used only in MAKE_BYTE_AVAIL */ 131#define INPUT_RELOAD(cinfo) \ 132 ( next_input_byte = datasrc->next_input_byte, \ 133 bytes_in_buffer = datasrc->bytes_in_buffer ) 134 135/* Internal macro for INPUT_BYTE and INPUT_2BYTES: make a byte available. 136 * Note we do *not* do INPUT_SYNC before calling fill_input_buffer, 137 * but we must reload the local copies after a successful fill. 138 */ 139#define MAKE_BYTE_AVAIL(cinfo,action) \ 140 if (bytes_in_buffer == 0) { \ 141 if (! (*datasrc->fill_input_buffer) (cinfo)) \ 142 { action; } \ 143 INPUT_RELOAD(cinfo); \ 144 } 145 146/* Read a byte into variable V. 147 * If must suspend, take the specified action (typically "return FALSE"). 148 */ 149#define INPUT_BYTE(cinfo,V,action) \ 150 MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \ 151 bytes_in_buffer--; \ 152 V = GETJOCTET(*next_input_byte++); ) 153 154/* As above, but read two bytes interpreted as an unsigned 16-bit integer. 155 * V should be declared unsigned int or perhaps INT32. 156 */ 157#define INPUT_2BYTES(cinfo,V,action) \ 158 MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \ 159 bytes_in_buffer--; \ 160 V = ((unsigned int) GETJOCTET(*next_input_byte++)) << 8; \ 161 MAKE_BYTE_AVAIL(cinfo,action); \ 162 bytes_in_buffer--; \ 163 V += GETJOCTET(*next_input_byte++); ) 164 165 166/* 167 * Routines to process JPEG markers. 168 * 169 * Entry condition: JPEG marker itself has been read and its code saved 170 * in cinfo->unread_marker; input restart point is just after the marker. 171 * 172 * Exit: if return TRUE, have read and processed any parameters, and have 173 * updated the restart point to point after the parameters. 174 * If return FALSE, was forced to suspend before reaching end of 175 * marker parameters; restart point has not been moved. Same routine 176 * will be called again after application supplies more input data. 177 * 178 * This approach to suspension assumes that all of a marker's parameters 179 * can fit into a single input bufferload. This should hold for "normal" 180 * markers. Some COM/APPn markers might have large parameter segments 181 * that might not fit. If we are simply dropping such a marker, we use 182 * skip_input_data to get past it, and thereby put the problem on the 183 * source manager's shoulders. If we are saving the marker's contents 184 * into memory, we use a slightly different convention: when forced to 185 * suspend, the marker processor updates the restart point to the end of 186 * what it's consumed (ie, the end of the buffer) before returning FALSE. 187 * On resumption, cinfo->unread_marker still contains the marker code, 188 * but the data source will point to the next chunk of marker data. 189 * The marker processor must retain internal state to deal with this. 190 * 191 * Note that we don't bother to avoid duplicate trace messages if a 192 * suspension occurs within marker parameters. Other side effects 193 * require more care. 194 */ 195 196 197LOCAL(boolean) 198get_soi (j_decompress_ptr cinfo) 199/* Process an SOI marker */ 200{ 201 int i; 202 203 TRACEMS(cinfo, 1, JTRC_SOI); 204 205 if (cinfo->marker->saw_SOI) 206 ERREXIT(cinfo, JERR_SOI_DUPLICATE); 207 208 /* Reset all parameters that are defined to be reset by SOI */ 209 210 for (i = 0; i < NUM_ARITH_TBLS; i++) { 211 cinfo->arith_dc_L[i] = 0; 212 cinfo->arith_dc_U[i] = 1; 213 cinfo->arith_ac_K[i] = 5; 214 } 215 cinfo->restart_interval = 0; 216 217 /* Set initial assumptions for colorspace etc */ 218 219 cinfo->jpeg_color_space = JCS_UNKNOWN; 220 cinfo->CCIR601_sampling = FALSE; /* Assume non-CCIR sampling??? */ 221 222 cinfo->saw_JFIF_marker = FALSE; 223 cinfo->JFIF_major_version = 1; /* set default JFIF APP0 values */ 224 cinfo->JFIF_minor_version = 1; 225 cinfo->density_unit = 0; 226 cinfo->X_density = 1; 227 cinfo->Y_density = 1; 228 cinfo->saw_Adobe_marker = FALSE; 229 cinfo->Adobe_transform = 0; 230 231 cinfo->marker->saw_SOI = TRUE; 232 233 return TRUE; 234} 235 236 237LOCAL(boolean) 238get_sof (j_decompress_ptr cinfo, boolean is_baseline, boolean is_prog, 239 boolean is_arith) 240/* Process a SOFn marker */ 241{ 242 INT32 length; 243 int c, ci; 244 jpeg_component_info * compptr; 245 INPUT_VARS(cinfo); 246 247 cinfo->is_baseline = is_baseline; 248 cinfo->progressive_mode = is_prog; 249 cinfo->arith_code = is_arith; 250 251 INPUT_2BYTES(cinfo, length, return FALSE); 252 253 INPUT_BYTE(cinfo, cinfo->data_precision, return FALSE); 254 INPUT_2BYTES(cinfo, cinfo->image_height, return FALSE); 255 INPUT_2BYTES(cinfo, cinfo->image_width, return FALSE); 256 INPUT_BYTE(cinfo, cinfo->num_components, return FALSE); 257 258 length -= 8; 259 260 TRACEMS4(cinfo, 1, JTRC_SOF, cinfo->unread_marker, 261 (int) cinfo->image_width, (int) cinfo->image_height, 262 cinfo->num_components); 263 264 if (cinfo->marker->saw_SOF) 265 ERREXIT(cinfo, JERR_SOF_DUPLICATE); 266 267 /* We don't support files in which the image height is initially specified */ 268 /* as 0 and is later redefined by DNL. As long as we have to check that, */ 269 /* might as well have a general sanity check. */ 270 if (cinfo->image_height <= 0 || cinfo->image_width <= 0 271 || cinfo->num_components <= 0) 272 ERREXIT(cinfo, JERR_EMPTY_IMAGE); 273 274 if (length != (cinfo->num_components * 3)) 275 ERREXIT(cinfo, JERR_BAD_LENGTH); 276 277 if (cinfo->comp_info == NULL) /* do only once, even if suspend */ 278 cinfo->comp_info = (jpeg_component_info *) (*cinfo->mem->alloc_small) 279 ((j_common_ptr) cinfo, JPOOL_IMAGE, 280 cinfo->num_components * SIZEOF(jpeg_component_info)); 281 282 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 283 ci++, compptr++) { 284 compptr->component_index = ci; 285 INPUT_BYTE(cinfo, compptr->component_id, return FALSE); 286 INPUT_BYTE(cinfo, c, return FALSE); 287 compptr->h_samp_factor = (c >> 4) & 15; 288 compptr->v_samp_factor = (c ) & 15; 289 INPUT_BYTE(cinfo, compptr->quant_tbl_no, return FALSE); 290 291 TRACEMS4(cinfo, 1, JTRC_SOF_COMPONENT, 292 compptr->component_id, compptr->h_samp_factor, 293 compptr->v_samp_factor, compptr->quant_tbl_no); 294 } 295 296 cinfo->marker->saw_SOF = TRUE; 297 298 INPUT_SYNC(cinfo); 299 return TRUE; 300} 301 302 303LOCAL(boolean) 304get_sos (j_decompress_ptr cinfo) 305/* Process a SOS marker */ 306{ 307 INT32 length; 308 int i, ci, n, c, cc; 309 jpeg_component_info * compptr; 310 INPUT_VARS(cinfo); 311 312 if (! cinfo->marker->saw_SOF) 313 ERREXIT(cinfo, JERR_SOS_NO_SOF); 314 315 INPUT_2BYTES(cinfo, length, return FALSE); 316 317 INPUT_BYTE(cinfo, n, return FALSE); /* Number of components */ 318 319 TRACEMS1(cinfo, 1, JTRC_SOS, n); 320 321 if (length != (n * 2 + 6) || n > MAX_COMPS_IN_SCAN || 322 (n == 0 && !cinfo->progressive_mode)) 323 /* pseudo SOS marker only allowed in progressive mode */ 324 ERREXIT(cinfo, JERR_BAD_LENGTH); 325 326 cinfo->comps_in_scan = n; 327 328 /* Collect the component-spec parameters */ 329 330 for (i = 0; i < n; i++) { 331 INPUT_BYTE(cinfo, cc, return FALSE); 332 INPUT_BYTE(cinfo, c, return FALSE); 333 334 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 335 ci++, compptr++) { 336 if (cc == compptr->component_id) 337 goto id_found; 338 } 339 340 ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc); 341 342 id_found: 343 344 cinfo->cur_comp_info[i] = compptr; 345 compptr->dc_tbl_no = (c >> 4) & 15; 346 compptr->ac_tbl_no = (c ) & 15; 347 348 TRACEMS3(cinfo, 1, JTRC_SOS_COMPONENT, cc, 349 compptr->dc_tbl_no, compptr->ac_tbl_no); 350 } 351 352 /* Collect the additional scan parameters Ss, Se, Ah/Al. */ 353 INPUT_BYTE(cinfo, c, return FALSE); 354 cinfo->Ss = c; 355 INPUT_BYTE(cinfo, c, return FALSE); 356 cinfo->Se = c; 357 INPUT_BYTE(cinfo, c, return FALSE); 358 cinfo->Ah = (c >> 4) & 15; 359 cinfo->Al = (c ) & 15; 360 361 TRACEMS4(cinfo, 1, JTRC_SOS_PARAMS, cinfo->Ss, cinfo->Se, 362 cinfo->Ah, cinfo->Al); 363 364 /* Prepare to scan data & restart markers */ 365 cinfo->marker->next_restart_num = 0; 366 367 /* Count another (non-pseudo) SOS marker */ 368 if (n) cinfo->input_scan_number++; 369 370 INPUT_SYNC(cinfo); 371 return TRUE; 372} 373 374 375#ifdef D_ARITH_CODING_SUPPORTED 376 377LOCAL(boolean) 378get_dac (j_decompress_ptr cinfo) 379/* Process a DAC marker */ 380{ 381 INT32 length; 382 int index, val; 383 INPUT_VARS(cinfo); 384 385 INPUT_2BYTES(cinfo, length, return FALSE); 386 length -= 2; 387 388 while (length > 0) { 389 INPUT_BYTE(cinfo, index, return FALSE); 390 INPUT_BYTE(cinfo, val, return FALSE); 391 392 length -= 2; 393 394 TRACEMS2(cinfo, 1, JTRC_DAC, index, val); 395 396 if (index < 0 || index >= (2*NUM_ARITH_TBLS)) 397 ERREXIT1(cinfo, JERR_DAC_INDEX, index); 398 399 if (index >= NUM_ARITH_TBLS) { /* define AC table */ 400 cinfo->arith_ac_K[index-NUM_ARITH_TBLS] = (UINT8) val; 401 } else { /* define DC table */ 402 cinfo->arith_dc_L[index] = (UINT8) (val & 0x0F); 403 cinfo->arith_dc_U[index] = (UINT8) (val >> 4); 404 if (cinfo->arith_dc_L[index] > cinfo->arith_dc_U[index]) 405 ERREXIT1(cinfo, JERR_DAC_VALUE, val); 406 } 407 } 408 409 if (length != 0) 410 ERREXIT(cinfo, JERR_BAD_LENGTH); 411 412 INPUT_SYNC(cinfo); 413 return TRUE; 414} 415 416#else /* ! D_ARITH_CODING_SUPPORTED */ 417 418#define get_dac(cinfo) skip_variable(cinfo) 419 420#endif /* D_ARITH_CODING_SUPPORTED */ 421 422 423LOCAL(boolean) 424get_dht (j_decompress_ptr cinfo) 425/* Process a DHT marker */ 426{ 427 INT32 length; 428 UINT8 bits[17]; 429 UINT8 huffval[256]; 430 int i, index, count; 431 JHUFF_TBL **htblptr; 432 INPUT_VARS(cinfo); 433 434 INPUT_2BYTES(cinfo, length, return FALSE); 435 length -= 2; 436 437 while (length > 16) { 438 INPUT_BYTE(cinfo, index, return FALSE); 439 440 TRACEMS1(cinfo, 1, JTRC_DHT, index); 441 442 bits[0] = 0; 443 count = 0; 444 for (i = 1; i <= 16; i++) { 445 INPUT_BYTE(cinfo, bits[i], return FALSE); 446 count += bits[i]; 447 } 448 449 length -= 1 + 16; 450 451 TRACEMS8(cinfo, 2, JTRC_HUFFBITS, 452 bits[1], bits[2], bits[3], bits[4], 453 bits[5], bits[6], bits[7], bits[8]); 454 TRACEMS8(cinfo, 2, JTRC_HUFFBITS, 455 bits[9], bits[10], bits[11], bits[12], 456 bits[13], bits[14], bits[15], bits[16]); 457 458 /* Here we just do minimal validation of the counts to avoid walking 459 * off the end of our table space. jdhuff.c will check more carefully. 460 */ 461 if (count > 256 || ((INT32) count) > length) 462 ERREXIT(cinfo, JERR_BAD_HUFF_TABLE); 463 464 for (i = 0; i < count; i++) 465 INPUT_BYTE(cinfo, huffval[i], return FALSE); 466 467 length -= count; 468 469 if (index & 0x10) { /* AC table definition */ 470 index -= 0x10; 471 htblptr = &cinfo->ac_huff_tbl_ptrs[index]; 472 } else { /* DC table definition */ 473 htblptr = &cinfo->dc_huff_tbl_ptrs[index]; 474 } 475 476 if (index < 0 || index >= NUM_HUFF_TBLS) 477 ERREXIT1(cinfo, JERR_DHT_INDEX, index); 478 479 if (*htblptr == NULL) 480 *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo); 481 482 MEMCOPY((*htblptr)->bits, bits, SIZEOF((*htblptr)->bits)); 483 MEMCOPY((*htblptr)->huffval, huffval, SIZEOF((*htblptr)->huffval)); 484 } 485 486 if (length != 0) 487 ERREXIT(cinfo, JERR_BAD_LENGTH); 488 489 INPUT_SYNC(cinfo); 490 return TRUE; 491} 492 493 494LOCAL(boolean) 495get_dqt (j_decompress_ptr cinfo) 496/* Process a DQT marker */ 497{ 498 INT32 length, count, i; 499 int n, prec; 500 unsigned int tmp; 501 JQUANT_TBL *quant_ptr; 502 const int *natural_order; 503 INPUT_VARS(cinfo); 504 505 INPUT_2BYTES(cinfo, length, return FALSE); 506 length -= 2; 507 508 while (length > 0) { 509 length--; 510 INPUT_BYTE(cinfo, n, return FALSE); 511 prec = n >> 4; 512 n &= 0x0F; 513 514 TRACEMS2(cinfo, 1, JTRC_DQT, n, prec); 515 516 if (n >= NUM_QUANT_TBLS) 517 ERREXIT1(cinfo, JERR_DQT_INDEX, n); 518 519 if (cinfo->quant_tbl_ptrs[n] == NULL) 520 cinfo->quant_tbl_ptrs[n] = jpeg_alloc_quant_table((j_common_ptr) cinfo); 521 quant_ptr = cinfo->quant_tbl_ptrs[n]; 522 523 if (prec) { 524 if (length < DCTSIZE2 * 2) { 525 /* Initialize full table for safety. */ 526 for (i = 0; i < DCTSIZE2; i++) { 527 quant_ptr->quantval[i] = 1; 528 } 529 count = length >> 1; 530 } else 531 count = DCTSIZE2; 532 } else { 533 if (length < DCTSIZE2) { 534 /* Initialize full table for safety. */ 535 for (i = 0; i < DCTSIZE2; i++) { 536 quant_ptr->quantval[i] = 1; 537 } 538 count = length; 539 } else 540 count = DCTSIZE2; 541 } 542 543 switch (count) { 544 case (2*2): natural_order = jpeg_natural_order2; break; 545 case (3*3): natural_order = jpeg_natural_order3; break; 546 case (4*4): natural_order = jpeg_natural_order4; break; 547 case (5*5): natural_order = jpeg_natural_order5; break; 548 case (6*6): natural_order = jpeg_natural_order6; break; 549 case (7*7): natural_order = jpeg_natural_order7; break; 550 default: natural_order = jpeg_natural_order; break; 551 } 552 553 for (i = 0; i < count; i++) { 554 if (prec) 555 INPUT_2BYTES(cinfo, tmp, return FALSE); 556 else 557 INPUT_BYTE(cinfo, tmp, return FALSE); 558 /* We convert the zigzag-order table to natural array order. */ 559 quant_ptr->quantval[natural_order[i]] = (UINT16) tmp; 560 } 561 562 if (cinfo->err->trace_level >= 2) { 563 for (i = 0; i < DCTSIZE2; i += 8) { 564 TRACEMS8(cinfo, 2, JTRC_QUANTVALS, 565 quant_ptr->quantval[i], quant_ptr->quantval[i+1], 566 quant_ptr->quantval[i+2], quant_ptr->quantval[i+3], 567 quant_ptr->quantval[i+4], quant_ptr->quantval[i+5], 568 quant_ptr->quantval[i+6], quant_ptr->quantval[i+7]); 569 } 570 } 571 572 length -= count; 573 if (prec) length -= count; 574 } 575 576 if (length != 0) 577 ERREXIT(cinfo, JERR_BAD_LENGTH); 578 579 INPUT_SYNC(cinfo); 580 return TRUE; 581} 582 583 584LOCAL(boolean) 585get_dri (j_decompress_ptr cinfo) 586/* Process a DRI marker */ 587{ 588 INT32 length; 589 unsigned int tmp; 590 INPUT_VARS(cinfo); 591 592 INPUT_2BYTES(cinfo, length, return FALSE); 593 594 if (length != 4) 595 ERREXIT(cinfo, JERR_BAD_LENGTH); 596 597 INPUT_2BYTES(cinfo, tmp, return FALSE); 598 599 TRACEMS1(cinfo, 1, JTRC_DRI, tmp); 600 601 cinfo->restart_interval = tmp; 602 603 INPUT_SYNC(cinfo); 604 return TRUE; 605} 606 607 608/* 609 * Routines for processing APPn and COM markers. 610 * These are either saved in memory or discarded, per application request. 611 * APP0 and APP14 are specially checked to see if they are 612 * JFIF and Adobe markers, respectively. 613 */ 614 615#define APP0_DATA_LEN 14 /* Length of interesting data in APP0 */ 616#define APP14_DATA_LEN 12 /* Length of interesting data in APP14 */ 617#define APPN_DATA_LEN 14 /* Must be the largest of the above!! */ 618 619 620LOCAL(void) 621examine_app0 (j_decompress_ptr cinfo, JOCTET FAR * data, 622 unsigned int datalen, INT32 remaining) 623/* Examine first few bytes from an APP0. 624 * Take appropriate action if it is a JFIF marker. 625 * datalen is # of bytes at data[], remaining is length of rest of marker data. 626 */ 627{ 628 INT32 totallen = (INT32) datalen + remaining; 629 630 if (datalen >= APP0_DATA_LEN && 631 GETJOCTET(data[0]) == 0x4A && 632 GETJOCTET(data[1]) == 0x46 && 633 GETJOCTET(data[2]) == 0x49 && 634 GETJOCTET(data[3]) == 0x46 && 635 GETJOCTET(data[4]) == 0) { 636 /* Found JFIF APP0 marker: save info */ 637 cinfo->saw_JFIF_marker = TRUE; 638 cinfo->JFIF_major_version = GETJOCTET(data[5]); 639 cinfo->JFIF_minor_version = GETJOCTET(data[6]); 640 cinfo->density_unit = GETJOCTET(data[7]); 641 cinfo->X_density = (GETJOCTET(data[8]) << 8) + GETJOCTET(data[9]); 642 cinfo->Y_density = (GETJOCTET(data[10]) << 8) + GETJOCTET(data[11]); 643 /* Check version. 644 * Major version must be 1, anything else signals an incompatible change. 645 * (We used to treat this as an error, but now it's a nonfatal warning, 646 * because some bozo at Hijaak couldn't read the spec.) 647 * Minor version should be 0..2, but process anyway if newer. 648 */ 649 if (cinfo->JFIF_major_version != 1) 650 WARNMS2(cinfo, JWRN_JFIF_MAJOR, 651 cinfo->JFIF_major_version, cinfo->JFIF_minor_version); 652 /* Generate trace messages */ 653 TRACEMS5(cinfo, 1, JTRC_JFIF, 654 cinfo->JFIF_major_version, cinfo->JFIF_minor_version, 655 cinfo->X_density, cinfo->Y_density, cinfo->density_unit); 656 /* Validate thumbnail dimensions and issue appropriate messages */ 657 if (GETJOCTET(data[12]) | GETJOCTET(data[13])) 658 TRACEMS2(cinfo, 1, JTRC_JFIF_THUMBNAIL, 659 GETJOCTET(data[12]), GETJOCTET(data[13])); 660 totallen -= APP0_DATA_LEN; 661 if (totallen != 662 ((INT32)GETJOCTET(data[12]) * (INT32)GETJOCTET(data[13]) * (INT32) 3)) 663 TRACEMS1(cinfo, 1, JTRC_JFIF_BADTHUMBNAILSIZE, (int) totallen); 664 } else if (datalen >= 6 && 665 GETJOCTET(data[0]) == 0x4A && 666 GETJOCTET(data[1]) == 0x46 && 667 GETJOCTET(data[2]) == 0x58 && 668 GETJOCTET(data[3]) == 0x58 && 669 GETJOCTET(data[4]) == 0) { 670 /* Found JFIF "JFXX" extension APP0 marker */ 671 /* The library doesn't actually do anything with these, 672 * but we try to produce a helpful trace message. 673 */ 674 switch (GETJOCTET(data[5])) { 675 case 0x10: 676 TRACEMS1(cinfo, 1, JTRC_THUMB_JPEG, (int) totallen); 677 break; 678 case 0x11: 679 TRACEMS1(cinfo, 1, JTRC_THUMB_PALETTE, (int) totallen); 680 break; 681 case 0x13: 682 TRACEMS1(cinfo, 1, JTRC_THUMB_RGB, (int) totallen); 683 break; 684 default: 685 TRACEMS2(cinfo, 1, JTRC_JFIF_EXTENSION, 686 GETJOCTET(data[5]), (int) totallen); 687 break; 688 } 689 } else { 690 /* Start of APP0 does not match "JFIF" or "JFXX", or too short */ 691 TRACEMS1(cinfo, 1, JTRC_APP0, (int) totallen); 692 } 693} 694 695 696LOCAL(void) 697examine_app14 (j_decompress_ptr cinfo, JOCTET FAR * data, 698 unsigned int datalen, INT32 remaining) 699/* Examine first few bytes from an APP14. 700 * Take appropriate action if it is an Adobe marker. 701 * datalen is # of bytes at data[], remaining is length of rest of marker data. 702 */ 703{ 704 unsigned int version, flags0, flags1, transform; 705 706 if (datalen >= APP14_DATA_LEN && 707 GETJOCTET(data[0]) == 0x41 && 708 GETJOCTET(data[1]) == 0x64 && 709 GETJOCTET(data[2]) == 0x6F && 710 GETJOCTET(data[3]) == 0x62 && 711 GETJOCTET(data[4]) == 0x65) { 712 /* Found Adobe APP14 marker */ 713 version = (GETJOCTET(data[5]) << 8) + GETJOCTET(data[6]); 714 flags0 = (GETJOCTET(data[7]) << 8) + GETJOCTET(data[8]); 715 flags1 = (GETJOCTET(data[9]) << 8) + GETJOCTET(data[10]); 716 transform = GETJOCTET(data[11]); 717 TRACEMS4(cinfo, 1, JTRC_ADOBE, version, flags0, flags1, transform); 718 cinfo->saw_Adobe_marker = TRUE; 719 cinfo->Adobe_transform = (UINT8) transform; 720 } else { 721 /* Start of APP14 does not match "Adobe", or too short */ 722 TRACEMS1(cinfo, 1, JTRC_APP14, (int) (datalen + remaining)); 723 } 724} 725 726 727METHODDEF(boolean) 728get_interesting_appn (j_decompress_ptr cinfo) 729/* Process an APP0 or APP14 marker without saving it */ 730{ 731 INT32 length; 732 JOCTET b[APPN_DATA_LEN]; 733 unsigned int i, numtoread; 734 INPUT_VARS(cinfo); 735 736 INPUT_2BYTES(cinfo, length, return FALSE); 737 length -= 2; 738 739 /* get the interesting part of the marker data */ 740 if (length >= APPN_DATA_LEN) 741 numtoread = APPN_DATA_LEN; 742 else if (length > 0) 743 numtoread = (unsigned int) length; 744 else 745 numtoread = 0; 746 for (i = 0; i < numtoread; i++) 747 INPUT_BYTE(cinfo, b[i], return FALSE); 748 length -= numtoread; 749 750 /* process it */ 751 switch (cinfo->unread_marker) { 752 case M_APP0: 753 examine_app0(cinfo, (JOCTET FAR *) b, numtoread, length); 754 break; 755 case M_APP14: 756 examine_app14(cinfo, (JOCTET FAR *) b, numtoread, length); 757 break; 758 default: 759 /* can't get here unless jpeg_save_markers chooses wrong processor */ 760 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker); 761 break; 762 } 763 764 /* skip any remaining data -- could be lots */ 765 INPUT_SYNC(cinfo); 766 if (length > 0) 767 (*cinfo->src->skip_input_data) (cinfo, (long) length); 768 769 return TRUE; 770} 771 772 773#ifdef SAVE_MARKERS_SUPPORTED 774 775METHODDEF(boolean) 776save_marker (j_decompress_ptr cinfo) 777/* Save an APPn or COM marker into the marker list */ 778{ 779 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 780 jpeg_saved_marker_ptr cur_marker = marker->cur_marker; 781 unsigned int bytes_read, data_length; 782 JOCTET FAR * data; 783 INT32 length = 0; 784 INPUT_VARS(cinfo); 785 786 if (cur_marker == NULL) { 787 /* begin reading a marker */ 788 INPUT_2BYTES(cinfo, length, return FALSE); 789 length -= 2; 790 if (length >= 0) { /* watch out for bogus length word */ 791 /* figure out how much we want to save */ 792 unsigned int limit; 793 if (cinfo->unread_marker == (int) M_COM) 794 limit = marker->length_limit_COM; 795 else 796 limit = marker->length_limit_APPn[cinfo->unread_marker - (int) M_APP0]; 797 if ((unsigned int) length < limit) 798 limit = (unsigned int) length; 799 /* allocate and initialize the marker item */ 800 cur_marker = (jpeg_saved_marker_ptr) 801 (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE, 802 SIZEOF(struct jpeg_marker_struct) + limit); 803 cur_marker->next = NULL; 804 cur_marker->marker = (UINT8) cinfo->unread_marker; 805 cur_marker->original_length = (unsigned int) length; 806 cur_marker->data_length = limit; 807 /* data area is just beyond the jpeg_marker_struct */ 808 data = cur_marker->data = (JOCTET FAR *) (cur_marker + 1); 809 marker->cur_marker = cur_marker; 810 marker->bytes_read = 0; 811 bytes_read = 0; 812 data_length = limit; 813 } else { 814 /* deal with bogus length word */ 815 bytes_read = data_length = 0; 816 data = NULL; 817 } 818 } else { 819 /* resume reading a marker */ 820 bytes_read = marker->bytes_read; 821 data_length = cur_marker->data_length; 822 data = cur_marker->data + bytes_read; 823 } 824 825 while (bytes_read < data_length) { 826 INPUT_SYNC(cinfo); /* move the restart point to here */ 827 marker->bytes_read = bytes_read; 828 /* If there's not at least one byte in buffer, suspend */ 829 MAKE_BYTE_AVAIL(cinfo, return FALSE); 830 /* Copy bytes with reasonable rapidity */ 831 while (bytes_read < data_length && bytes_in_buffer > 0) { 832 *data++ = *next_input_byte++; 833 bytes_in_buffer--; 834 bytes_read++; 835 } 836 } 837 838 /* Done reading what we want to read */ 839 if (cur_marker != NULL) { /* will be NULL if bogus length word */ 840 /* Add new marker to end of list */ 841 if (cinfo->marker_list == NULL) { 842 cinfo->marker_list = cur_marker; 843 } else { 844 jpeg_saved_marker_ptr prev = cinfo->marker_list; 845 while (prev->next != NULL) 846 prev = prev->next; 847 prev->next = cur_marker; 848 } 849 /* Reset pointer & calc remaining data length */ 850 data = cur_marker->data; 851 length = cur_marker->original_length - data_length; 852 } 853 /* Reset to initial state for next marker */ 854 marker->cur_marker = NULL; 855 856 /* Process the marker if interesting; else just make a generic trace msg */ 857 switch (cinfo->unread_marker) { 858 case M_APP0: 859 examine_app0(cinfo, data, data_length, length); 860 break; 861 case M_APP14: 862 examine_app14(cinfo, data, data_length, length); 863 break; 864 default: 865 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, 866 (int) (data_length + length)); 867 break; 868 } 869 870 /* skip any remaining data -- could be lots */ 871 INPUT_SYNC(cinfo); /* do before skip_input_data */ 872 if (length > 0) 873 (*cinfo->src->skip_input_data) (cinfo, (long) length); 874 875 return TRUE; 876} 877 878#endif /* SAVE_MARKERS_SUPPORTED */ 879 880 881METHODDEF(boolean) 882skip_variable (j_decompress_ptr cinfo) 883/* Skip over an unknown or uninteresting variable-length marker */ 884{ 885 INT32 length; 886 INPUT_VARS(cinfo); 887 888 INPUT_2BYTES(cinfo, length, return FALSE); 889 length -= 2; 890 891 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, (int) length); 892 893 INPUT_SYNC(cinfo); /* do before skip_input_data */ 894 if (length > 0) 895 (*cinfo->src->skip_input_data) (cinfo, (long) length); 896 897 return TRUE; 898} 899 900 901/* 902 * Find the next JPEG marker, save it in cinfo->unread_marker. 903 * Returns FALSE if had to suspend before reaching a marker; 904 * in that case cinfo->unread_marker is unchanged. 905 * 906 * Note that the result might not be a valid marker code, 907 * but it will never be 0 or FF. 908 */ 909 910LOCAL(boolean) 911next_marker (j_decompress_ptr cinfo) 912{ 913 int c; 914 INPUT_VARS(cinfo); 915 916 for (;;) { 917 INPUT_BYTE(cinfo, c, return FALSE); 918 /* Skip any non-FF bytes. 919 * This may look a bit inefficient, but it will not occur in a valid file. 920 * We sync after each discarded byte so that a suspending data source 921 * can discard the byte from its buffer. 922 */ 923 while (c != 0xFF) { 924 cinfo->marker->discarded_bytes++; 925 INPUT_SYNC(cinfo); 926 INPUT_BYTE(cinfo, c, return FALSE); 927 } 928 /* This loop swallows any duplicate FF bytes. Extra FFs are legal as 929 * pad bytes, so don't count them in discarded_bytes. We assume there 930 * will not be so many consecutive FF bytes as to overflow a suspending 931 * data source's input buffer. 932 */ 933 do { 934 INPUT_BYTE(cinfo, c, return FALSE); 935 } while (c == 0xFF); 936 if (c != 0) 937 break; /* found a valid marker, exit loop */ 938 /* Reach here if we found a stuffed-zero data sequence (FF/00). 939 * Discard it and loop back to try again. 940 */ 941 cinfo->marker->discarded_bytes += 2; 942 INPUT_SYNC(cinfo); 943 } 944 945 if (cinfo->marker->discarded_bytes != 0) { 946 WARNMS2(cinfo, JWRN_EXTRANEOUS_DATA, cinfo->marker->discarded_bytes, c); 947 cinfo->marker->discarded_bytes = 0; 948 } 949 950 cinfo->unread_marker = c; 951 952 INPUT_SYNC(cinfo); 953 return TRUE; 954} 955 956 957LOCAL(boolean) 958first_marker (j_decompress_ptr cinfo) 959/* Like next_marker, but used to obtain the initial SOI marker. */ 960/* For this marker, we do not allow preceding garbage or fill; otherwise, 961 * we might well scan an entire input file before realizing it ain't JPEG. 962 * If an application wants to process non-JFIF files, it must seek to the 963 * SOI before calling the JPEG library. 964 */ 965{ 966 int c, c2; 967 INPUT_VARS(cinfo); 968 969 INPUT_BYTE(cinfo, c, return FALSE); 970 INPUT_BYTE(cinfo, c2, return FALSE); 971 if (c != 0xFF || c2 != (int) M_SOI) 972 ERREXIT2(cinfo, JERR_NO_SOI, c, c2); 973 974 cinfo->unread_marker = c2; 975 976 INPUT_SYNC(cinfo); 977 return TRUE; 978} 979 980 981/* 982 * Read markers until SOS or EOI. 983 * 984 * Returns same codes as are defined for jpeg_consume_input: 985 * JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI. 986 * 987 * Note: This function may return a pseudo SOS marker (with zero 988 * component number) for treat by input controller's consume_input. 989 * consume_input itself should filter out (skip) the pseudo marker 990 * after processing for the caller. 991 */ 992 993METHODDEF(int) 994read_markers (j_decompress_ptr cinfo) 995{ 996 /* Outer loop repeats once for each marker. */ 997 for (;;) { 998 /* Collect the marker proper, unless we already did. */ 999 /* NB: first_marker() enforces the requirement that SOI appear first. */ 1000 if (cinfo->unread_marker == 0) { 1001 if (! cinfo->marker->saw_SOI) { 1002 if (! first_marker(cinfo)) 1003 return JPEG_SUSPENDED; 1004 } else { 1005 if (! next_marker(cinfo)) 1006 return JPEG_SUSPENDED; 1007 } 1008 } 1009 /* At this point cinfo->unread_marker contains the marker code and the 1010 * input point is just past the marker proper, but before any parameters. 1011 * A suspension will cause us to return with this state still true. 1012 */ 1013 switch (cinfo->unread_marker) { 1014 case M_SOI: 1015 if (! get_soi(cinfo)) 1016 return JPEG_SUSPENDED; 1017 break; 1018 1019 case M_SOF0: /* Baseline */ 1020 if (! get_sof(cinfo, TRUE, FALSE, FALSE)) 1021 return JPEG_SUSPENDED; 1022 break; 1023 1024 case M_SOF1: /* Extended sequential, Huffman */ 1025 if (! get_sof(cinfo, FALSE, FALSE, FALSE)) 1026 return JPEG_SUSPENDED; 1027 break; 1028 1029 case M_SOF2: /* Progressive, Huffman */ 1030 if (! get_sof(cinfo, FALSE, TRUE, FALSE)) 1031 return JPEG_SUSPENDED; 1032 break; 1033 1034 case M_SOF9: /* Extended sequential, arithmetic */ 1035 if (! get_sof(cinfo, FALSE, FALSE, TRUE)) 1036 return JPEG_SUSPENDED; 1037 break; 1038 1039 case M_SOF10: /* Progressive, arithmetic */ 1040 if (! get_sof(cinfo, FALSE, TRUE, TRUE)) 1041 return JPEG_SUSPENDED; 1042 break; 1043 1044 /* Currently unsupported SOFn types */ 1045 case M_SOF3: /* Lossless, Huffman */ 1046 case M_SOF5: /* Differential sequential, Huffman */ 1047 case M_SOF6: /* Differential progressive, Huffman */ 1048 case M_SOF7: /* Differential lossless, Huffman */ 1049 case M_JPG: /* Reserved for JPEG extensions */ 1050 case M_SOF11: /* Lossless, arithmetic */ 1051 case M_SOF13: /* Differential sequential, arithmetic */ 1052 case M_SOF14: /* Differential progressive, arithmetic */ 1053 case M_SOF15: /* Differential lossless, arithmetic */ 1054 ERREXIT1(cinfo, JERR_SOF_UNSUPPORTED, cinfo->unread_marker); 1055 break; 1056 1057 case M_SOS: 1058 if (! get_sos(cinfo)) 1059 return JPEG_SUSPENDED; 1060 cinfo->unread_marker = 0; /* processed the marker */ 1061 return JPEG_REACHED_SOS; 1062 1063 case M_EOI: 1064 TRACEMS(cinfo, 1, JTRC_EOI); 1065 cinfo->unread_marker = 0; /* processed the marker */ 1066 return JPEG_REACHED_EOI; 1067 1068 case M_DAC: 1069 if (! get_dac(cinfo)) 1070 return JPEG_SUSPENDED; 1071 break; 1072 1073 case M_DHT: 1074 if (! get_dht(cinfo)) 1075 return JPEG_SUSPENDED; 1076 break; 1077 1078 case M_DQT: 1079 if (! get_dqt(cinfo)) 1080 return JPEG_SUSPENDED; 1081 break; 1082 1083 case M_DRI: 1084 if (! get_dri(cinfo)) 1085 return JPEG_SUSPENDED; 1086 break; 1087 1088 case M_APP0: 1089 case M_APP1: 1090 case M_APP2: 1091 case M_APP3: 1092 case M_APP4: 1093 case M_APP5: 1094 case M_APP6: 1095 case M_APP7: 1096 case M_APP8: 1097 case M_APP9: 1098 case M_APP10: 1099 case M_APP11: 1100 case M_APP12: 1101 case M_APP13: 1102 case M_APP14: 1103 case M_APP15: 1104 if (! (*((my_marker_ptr) cinfo->marker)->process_APPn[ 1105 cinfo->unread_marker - (int) M_APP0]) (cinfo)) 1106 return JPEG_SUSPENDED; 1107 break; 1108 1109 case M_COM: 1110 if (! (*((my_marker_ptr) cinfo->marker)->process_COM) (cinfo)) 1111 return JPEG_SUSPENDED; 1112 break; 1113 1114 case M_RST0: /* these are all parameterless */ 1115 case M_RST1: 1116 case M_RST2: 1117 case M_RST3: 1118 case M_RST4: 1119 case M_RST5: 1120 case M_RST6: 1121 case M_RST7: 1122 case M_TEM: 1123 TRACEMS1(cinfo, 1, JTRC_PARMLESS_MARKER, cinfo->unread_marker); 1124 break; 1125 1126 case M_DNL: /* Ignore DNL ... perhaps the wrong thing */ 1127 if (! skip_variable(cinfo)) 1128 return JPEG_SUSPENDED; 1129 break; 1130 1131 default: /* must be DHP, EXP, JPGn, or RESn */ 1132 /* For now, we treat the reserved markers as fatal errors since they are 1133 * likely to be used to signal incompatible JPEG Part 3 extensions. 1134 * Once the JPEG 3 version-number marker is well defined, this code 1135 * ought to change! 1136 */ 1137 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker); 1138 break; 1139 } 1140 /* Successfully processed marker, so reset state variable */ 1141 cinfo->unread_marker = 0; 1142 } /* end loop */ 1143} 1144 1145 1146/* 1147 * Read a restart marker, which is expected to appear next in the datastream; 1148 * if the marker is not there, take appropriate recovery action. 1149 * Returns FALSE if suspension is required. 1150 * 1151 * This is called by the entropy decoder after it has read an appropriate 1152 * number of MCUs. cinfo->unread_marker may be nonzero if the entropy decoder 1153 * has already read a marker from the data source. Under normal conditions 1154 * cinfo->unread_marker will be reset to 0 before returning; if not reset, 1155 * it holds a marker which the decoder will be unable to read past. 1156 */ 1157 1158METHODDEF(boolean) 1159read_restart_marker (j_decompress_ptr cinfo) 1160{ 1161 /* Obtain a marker unless we already did. */ 1162 /* Note that next_marker will complain if it skips any data. */ 1163 if (cinfo->unread_marker == 0) { 1164 if (! next_marker(cinfo)) 1165 return FALSE; 1166 } 1167 1168 if (cinfo->unread_marker == 1169 ((int) M_RST0 + cinfo->marker->next_restart_num)) { 1170 /* Normal case --- swallow the marker and let entropy decoder continue */ 1171 TRACEMS1(cinfo, 3, JTRC_RST, cinfo->marker->next_restart_num); 1172 cinfo->unread_marker = 0; 1173 } else { 1174 /* Uh-oh, the restart markers have been messed up. */ 1175 /* Let the data source manager determine how to resync. */ 1176 if (! (*cinfo->src->resync_to_restart) (cinfo, 1177 cinfo->marker->next_restart_num)) 1178 return FALSE; 1179 } 1180 1181 /* Update next-restart state */ 1182 cinfo->marker->next_restart_num = (cinfo->marker->next_restart_num + 1) & 7; 1183 1184 return TRUE; 1185} 1186 1187 1188/* 1189 * This is the default resync_to_restart method for data source managers 1190 * to use if they don't have any better approach. Some data source managers 1191 * may be able to back up, or may have additional knowledge about the data 1192 * which permits a more intelligent recovery strategy; such managers would 1193 * presumably supply their own resync method. 1194 * 1195 * read_restart_marker calls resync_to_restart if it finds a marker other than 1196 * the restart marker it was expecting. (This code is *not* used unless 1197 * a nonzero restart interval has been declared.) cinfo->unread_marker is 1198 * the marker code actually found (might be anything, except 0 or FF). 1199 * The desired restart marker number (0..7) is passed as a parameter. 1200 * This routine is supposed to apply whatever error recovery strategy seems 1201 * appropriate in order to position the input stream to the next data segment. 1202 * Note that cinfo->unread_marker is treated as a marker appearing before 1203 * the current data-source input point; usually it should be reset to zero 1204 * before returning. 1205 * Returns FALSE if suspension is required. 1206 * 1207 * This implementation is substantially constrained by wanting to treat the 1208 * input as a data stream; this means we can't back up. Therefore, we have 1209 * only the following actions to work with: 1210 * 1. Simply discard the marker and let the entropy decoder resume at next 1211 * byte of file. 1212 * 2. Read forward until we find another marker, discarding intervening 1213 * data. (In theory we could look ahead within the current bufferload, 1214 * without having to discard data if we don't find the desired marker. 1215 * This idea is not implemented here, in part because it makes behavior 1216 * dependent on buffer size and chance buffer-boundary positions.) 1217 * 3. Leave the marker unread (by failing to zero cinfo->unread_marker). 1218 * This will cause the entropy decoder to process an empty data segment, 1219 * inserting dummy zeroes, and then we will reprocess the marker. 1220 * 1221 * #2 is appropriate if we think the desired marker lies ahead, while #3 is 1222 * appropriate if the found marker is a future restart marker (indicating 1223 * that we have missed the desired restart marker, probably because it got 1224 * corrupted). 1225 * We apply #2 or #3 if the found marker is a restart marker no more than 1226 * two counts behind or ahead of the expected one. We also apply #2 if the 1227 * found marker is not a legal JPEG marker code (it's certainly bogus data). 1228 * If the found marker is a restart marker more than 2 counts away, we do #1 1229 * (too much risk that the marker is erroneous; with luck we will be able to 1230 * resync at some future point). 1231 * For any valid non-restart JPEG marker, we apply #3. This keeps us from 1232 * overrunning the end of a scan. An implementation limited to single-scan 1233 * files might find it better to apply #2 for markers other than EOI, since 1234 * any other marker would have to be bogus data in that case. 1235 */ 1236 1237GLOBAL(boolean) 1238jpeg_resync_to_restart (j_decompress_ptr cinfo, int desired) 1239{ 1240 int marker = cinfo->unread_marker; 1241 int action = 1; 1242 1243 /* Always put up a warning. */ 1244 WARNMS2(cinfo, JWRN_MUST_RESYNC, marker, desired); 1245 1246 /* Outer loop handles repeated decision after scanning forward. */ 1247 for (;;) { 1248 if (marker < (int) M_SOF0) 1249 action = 2; /* invalid marker */ 1250 else if (marker < (int) M_RST0 || marker > (int) M_RST7) 1251 action = 3; /* valid non-restart marker */ 1252 else { 1253 if (marker == ((int) M_RST0 + ((desired+1) & 7)) || 1254 marker == ((int) M_RST0 + ((desired+2) & 7))) 1255 action = 3; /* one of the next two expected restarts */ 1256 else if (marker == ((int) M_RST0 + ((desired-1) & 7)) || 1257 marker == ((int) M_RST0 + ((desired-2) & 7))) 1258 action = 2; /* a prior restart, so advance */ 1259 else 1260 action = 1; /* desired restart or too far away */ 1261 } 1262 TRACEMS2(cinfo, 4, JTRC_RECOVERY_ACTION, marker, action); 1263 switch (action) { 1264 case 1: 1265 /* Discard marker and let entropy decoder resume processing. */ 1266 cinfo->unread_marker = 0; 1267 return TRUE; 1268 case 2: 1269 /* Scan to the next marker, and repeat the decision loop. */ 1270 if (! next_marker(cinfo)) 1271 return FALSE; 1272 marker = cinfo->unread_marker; 1273 break; 1274 case 3: 1275 /* Return without advancing past this marker. */ 1276 /* Entropy decoder will be forced to process an empty segment. */ 1277 return TRUE; 1278 } 1279 } /* end loop */ 1280} 1281 1282 1283/* 1284 * Reset marker processing state to begin a fresh datastream. 1285 */ 1286 1287METHODDEF(void) 1288reset_marker_reader (j_decompress_ptr cinfo) 1289{ 1290 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 1291 1292 cinfo->comp_info = NULL; /* until allocated by get_sof */ 1293 cinfo->input_scan_number = 0; /* no SOS seen yet */ 1294 cinfo->unread_marker = 0; /* no pending marker */ 1295 marker->pub.saw_SOI = FALSE; /* set internal state too */ 1296 marker->pub.saw_SOF = FALSE; 1297 marker->pub.discarded_bytes = 0; 1298 marker->cur_marker = NULL; 1299} 1300 1301 1302/* 1303 * Initialize the marker reader module. 1304 * This is called only once, when the decompression object is created. 1305 */ 1306 1307GLOBAL(void) 1308jinit_marker_reader (j_decompress_ptr cinfo) 1309{ 1310 my_marker_ptr marker; 1311 int i; 1312 1313 /* Create subobject in permanent pool */ 1314 marker = (my_marker_ptr) 1315 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT, 1316 SIZEOF(my_marker_reader)); 1317 cinfo->marker = (struct jpeg_marker_reader *) marker; 1318 /* Initialize public method pointers */ 1319 marker->pub.reset_marker_reader = reset_marker_reader; 1320 marker->pub.read_markers = read_markers; 1321 marker->pub.read_restart_marker = read_restart_marker; 1322 /* Initialize COM/APPn processing. 1323 * By default, we examine and then discard APP0 and APP14, 1324 * but simply discard COM and all other APPn. 1325 */ 1326 marker->process_COM = skip_variable; 1327 marker->length_limit_COM = 0; 1328 for (i = 0; i < 16; i++) { 1329 marker->process_APPn[i] = skip_variable; 1330 marker->length_limit_APPn[i] = 0; 1331 } 1332 marker->process_APPn[0] = get_interesting_appn; 1333 marker->process_APPn[14] = get_interesting_appn; 1334 /* Reset marker processing state */ 1335 reset_marker_reader(cinfo); 1336} 1337 1338 1339/* 1340 * Control saving of COM and APPn markers into marker_list. 1341 */ 1342 1343#ifdef SAVE_MARKERS_SUPPORTED 1344 1345GLOBAL(void) 1346jpeg_save_markers (j_decompress_ptr cinfo, int marker_code, 1347 unsigned int length_limit) 1348{ 1349 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 1350 long maxlength; 1351 jpeg_marker_parser_method processor; 1352 1353 /* Length limit mustn't be larger than what we can allocate 1354 * (should only be a concern in a 16-bit environment). 1355 */ 1356 maxlength = cinfo->mem->max_alloc_chunk - SIZEOF(struct jpeg_marker_struct); 1357 if (((long) length_limit) > maxlength) 1358 length_limit = (unsigned int) maxlength; 1359 1360 /* Choose processor routine to use. 1361 * APP0/APP14 have special requirements. 1362 */ 1363 if (length_limit) { 1364 processor = save_marker; 1365 /* If saving APP0/APP14, save at least enough for our internal use. */ 1366 if (marker_code == (int) M_APP0 && length_limit < APP0_DATA_LEN) 1367 length_limit = APP0_DATA_LEN; 1368 else if (marker_code == (int) M_APP14 && length_limit < APP14_DATA_LEN) 1369 length_limit = APP14_DATA_LEN; 1370 } else { 1371 processor = skip_variable; 1372 /* If discarding APP0/APP14, use our regular on-the-fly processor. */ 1373 if (marker_code == (int) M_APP0 || marker_code == (int) M_APP14) 1374 processor = get_interesting_appn; 1375 } 1376 1377 if (marker_code == (int) M_COM) { 1378 marker->process_COM = processor; 1379 marker->length_limit_COM = length_limit; 1380 } else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15) { 1381 marker->process_APPn[marker_code - (int) M_APP0] = processor; 1382 marker->length_limit_APPn[marker_code - (int) M_APP0] = length_limit; 1383 } else 1384 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code); 1385} 1386 1387#endif /* SAVE_MARKERS_SUPPORTED */ 1388 1389 1390/* 1391 * Install a special processing method for COM or APPn markers. 1392 */ 1393 1394GLOBAL(void) 1395jpeg_set_marker_processor (j_decompress_ptr cinfo, int marker_code, 1396 jpeg_marker_parser_method routine) 1397{ 1398 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 1399 1400 if (marker_code == (int) M_COM) 1401 marker->process_COM = routine; 1402 else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15) 1403 marker->process_APPn[marker_code - (int) M_APP0] = routine; 1404 else 1405 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code); 1406} 1407