1/* 2 * reserved comment block 3 * DO NOT REMOVE OR ALTER! 4 */ 5/* 6 * jdmarker.c 7 * 8 * Copyright (C) 1991-1998, Thomas G. Lane. 9 * This file is part of the Independent JPEG Group's software. 10 * For conditions of distribution and use, see the accompanying README file. 11 * 12 * This file contains routines to decode JPEG datastream markers. 13 * Most of the complexity arises from our desire to support input 14 * suspension: if not all of the data for a marker is available, 15 * we must exit back to the application. On resumption, we reprocess 16 * the marker. 17 */ 18 19#define JPEG_INTERNALS 20#include "jinclude.h" 21#include "jpeglib.h" 22 23 24typedef enum { /* JPEG marker codes */ 25 M_SOF0 = 0xc0, 26 M_SOF1 = 0xc1, 27 M_SOF2 = 0xc2, 28 M_SOF3 = 0xc3, 29 30 M_SOF5 = 0xc5, 31 M_SOF6 = 0xc6, 32 M_SOF7 = 0xc7, 33 34 M_JPG = 0xc8, 35 M_SOF9 = 0xc9, 36 M_SOF10 = 0xca, 37 M_SOF11 = 0xcb, 38 39 M_SOF13 = 0xcd, 40 M_SOF14 = 0xce, 41 M_SOF15 = 0xcf, 42 43 M_DHT = 0xc4, 44 45 M_DAC = 0xcc, 46 47 M_RST0 = 0xd0, 48 M_RST1 = 0xd1, 49 M_RST2 = 0xd2, 50 M_RST3 = 0xd3, 51 M_RST4 = 0xd4, 52 M_RST5 = 0xd5, 53 M_RST6 = 0xd6, 54 M_RST7 = 0xd7, 55 56 M_SOI = 0xd8, 57 M_EOI = 0xd9, 58 M_SOS = 0xda, 59 M_DQT = 0xdb, 60 M_DNL = 0xdc, 61 M_DRI = 0xdd, 62 M_DHP = 0xde, 63 M_EXP = 0xdf, 64 65 M_APP0 = 0xe0, 66 M_APP1 = 0xe1, 67 M_APP2 = 0xe2, 68 M_APP3 = 0xe3, 69 M_APP4 = 0xe4, 70 M_APP5 = 0xe5, 71 M_APP6 = 0xe6, 72 M_APP7 = 0xe7, 73 M_APP8 = 0xe8, 74 M_APP9 = 0xe9, 75 M_APP10 = 0xea, 76 M_APP11 = 0xeb, 77 M_APP12 = 0xec, 78 M_APP13 = 0xed, 79 M_APP14 = 0xee, 80 M_APP15 = 0xef, 81 82 M_JPG0 = 0xf0, 83 M_JPG13 = 0xfd, 84 M_COM = 0xfe, 85 86 M_TEM = 0x01, 87 88 M_ERROR = 0x100 89} JPEG_MARKER; 90 91 92/* Private state */ 93 94typedef struct { 95 struct jpeg_marker_reader pub; /* public fields */ 96 97 /* Application-overridable marker processing methods */ 98 jpeg_marker_parser_method process_COM; 99 jpeg_marker_parser_method process_APPn[16]; 100 101 /* Limit on marker data length to save for each marker type */ 102 unsigned int length_limit_COM; 103 unsigned int length_limit_APPn[16]; 104 105 /* Status of COM/APPn marker saving */ 106 jpeg_saved_marker_ptr cur_marker; /* NULL if not processing a marker */ 107 unsigned int bytes_read; /* data bytes read so far in marker */ 108 /* Note: cur_marker is not linked into marker_list until it's all read. */ 109} my_marker_reader; 110 111typedef my_marker_reader * my_marker_ptr; 112 113 114/* 115 * Macros for fetching data from the data source module. 116 * 117 * At all times, cinfo->src->next_input_byte and ->bytes_in_buffer reflect 118 * the current restart point; we update them only when we have reached a 119 * suitable place to restart if a suspension occurs. 120 */ 121 122/* Declare and initialize local copies of input pointer/count */ 123#define INPUT_VARS(cinfo) \ 124 struct jpeg_source_mgr * datasrc = (cinfo)->src; \ 125 const JOCTET * next_input_byte = datasrc->next_input_byte; \ 126 size_t bytes_in_buffer = datasrc->bytes_in_buffer 127 128/* Unload the local copies --- do this only at a restart boundary */ 129#define INPUT_SYNC(cinfo) \ 130 ( datasrc->next_input_byte = next_input_byte, \ 131 datasrc->bytes_in_buffer = bytes_in_buffer ) 132 133/* Reload the local copies --- used only in MAKE_BYTE_AVAIL */ 134#define INPUT_RELOAD(cinfo) \ 135 ( next_input_byte = datasrc->next_input_byte, \ 136 bytes_in_buffer = datasrc->bytes_in_buffer ) 137 138/* Internal macro for INPUT_BYTE and INPUT_2BYTES: make a byte available. 139 * Note we do *not* do INPUT_SYNC before calling fill_input_buffer, 140 * but we must reload the local copies after a successful fill. 141 */ 142#define MAKE_BYTE_AVAIL(cinfo,action) \ 143 if (bytes_in_buffer == 0) { \ 144 if (! (*datasrc->fill_input_buffer) (cinfo)) \ 145 { action; } \ 146 INPUT_RELOAD(cinfo); \ 147 } 148 149/* Read a byte into variable V. 150 * If must suspend, take the specified action (typically "return FALSE"). 151 */ 152#define INPUT_BYTE(cinfo,V,action) \ 153 MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \ 154 bytes_in_buffer--; \ 155 V = GETJOCTET(*next_input_byte++); ) 156 157/* As above, but read two bytes interpreted as an unsigned 16-bit integer. 158 * V should be declared unsigned int or perhaps INT32. 159 */ 160#define INPUT_2BYTES(cinfo,V,action) \ 161 MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \ 162 bytes_in_buffer--; \ 163 V = ((unsigned int) GETJOCTET(*next_input_byte++)) << 8; \ 164 MAKE_BYTE_AVAIL(cinfo,action); \ 165 bytes_in_buffer--; \ 166 V += GETJOCTET(*next_input_byte++); ) 167 168 169/* 170 * Routines to process JPEG markers. 171 * 172 * Entry condition: JPEG marker itself has been read and its code saved 173 * in cinfo->unread_marker; input restart point is just after the marker. 174 * 175 * Exit: if return TRUE, have read and processed any parameters, and have 176 * updated the restart point to point after the parameters. 177 * If return FALSE, was forced to suspend before reaching end of 178 * marker parameters; restart point has not been moved. Same routine 179 * will be called again after application supplies more input data. 180 * 181 * This approach to suspension assumes that all of a marker's parameters 182 * can fit into a single input bufferload. This should hold for "normal" 183 * markers. Some COM/APPn markers might have large parameter segments 184 * that might not fit. If we are simply dropping such a marker, we use 185 * skip_input_data to get past it, and thereby put the problem on the 186 * source manager's shoulders. If we are saving the marker's contents 187 * into memory, we use a slightly different convention: when forced to 188 * suspend, the marker processor updates the restart point to the end of 189 * what it's consumed (ie, the end of the buffer) before returning FALSE. 190 * On resumption, cinfo->unread_marker still contains the marker code, 191 * but the data source will point to the next chunk of marker data. 192 * The marker processor must retain internal state to deal with this. 193 * 194 * Note that we don't bother to avoid duplicate trace messages if a 195 * suspension occurs within marker parameters. Other side effects 196 * require more care. 197 */ 198 199 200LOCAL(boolean) 201get_soi (j_decompress_ptr cinfo) 202/* Process an SOI marker */ 203{ 204 int i; 205 206 TRACEMS(cinfo, 1, JTRC_SOI); 207 208 if (cinfo->marker->saw_SOI) 209 ERREXIT(cinfo, JERR_SOI_DUPLICATE); 210 211 /* Reset all parameters that are defined to be reset by SOI */ 212 213 for (i = 0; i < NUM_ARITH_TBLS; i++) { 214 cinfo->arith_dc_L[i] = 0; 215 cinfo->arith_dc_U[i] = 1; 216 cinfo->arith_ac_K[i] = 5; 217 } 218 cinfo->restart_interval = 0; 219 220 /* Set initial assumptions for colorspace etc */ 221 222 cinfo->jpeg_color_space = JCS_UNKNOWN; 223 cinfo->CCIR601_sampling = FALSE; /* Assume non-CCIR sampling??? */ 224 225 cinfo->saw_JFIF_marker = FALSE; 226 cinfo->JFIF_major_version = 1; /* set default JFIF APP0 values */ 227 cinfo->JFIF_minor_version = 1; 228 cinfo->density_unit = 0; 229 cinfo->X_density = 1; 230 cinfo->Y_density = 1; 231 cinfo->saw_Adobe_marker = FALSE; 232 cinfo->Adobe_transform = 0; 233 234 cinfo->marker->saw_SOI = TRUE; 235 236 return TRUE; 237} 238 239 240LOCAL(boolean) 241get_sof (j_decompress_ptr cinfo, boolean is_prog, boolean is_arith) 242/* Process a SOFn marker */ 243{ 244 INT32 length; 245 int c, ci; 246 jpeg_component_info * compptr; 247 INPUT_VARS(cinfo); 248 249 cinfo->progressive_mode = is_prog; 250 cinfo->arith_code = is_arith; 251 252 INPUT_2BYTES(cinfo, length, return FALSE); 253 254 INPUT_BYTE(cinfo, cinfo->data_precision, return FALSE); 255 INPUT_2BYTES(cinfo, cinfo->image_height, return FALSE); 256 INPUT_2BYTES(cinfo, cinfo->image_width, return FALSE); 257 INPUT_BYTE(cinfo, cinfo->num_components, return FALSE); 258 259 length -= 8; 260 261 TRACEMS4(cinfo, 1, JTRC_SOF, cinfo->unread_marker, 262 (int) cinfo->image_width, (int) cinfo->image_height, 263 cinfo->num_components); 264 265 if (cinfo->marker->saw_SOF) 266 ERREXIT(cinfo, JERR_SOF_DUPLICATE); 267 268 /* We don't support files in which the image height is initially specified */ 269 /* as 0 and is later redefined by DNL. As long as we have to check that, */ 270 /* might as well have a general sanity check. */ 271 if (cinfo->image_height <= 0 || cinfo->image_width <= 0 272 || cinfo->num_components <= 0) 273 ERREXIT(cinfo, JERR_EMPTY_IMAGE); 274 275 if (length != (cinfo->num_components * 3)) 276 ERREXIT(cinfo, JERR_BAD_LENGTH); 277 278 if (cinfo->comp_info == NULL) { /* do only once, even if suspend */ 279 cinfo->comp_info = (jpeg_component_info *) (*cinfo->mem->alloc_small) 280 ((j_common_ptr) cinfo, JPOOL_IMAGE, 281 cinfo->num_components * SIZEOF(jpeg_component_info)); 282 MEMZERO(cinfo->comp_info, 283 cinfo->num_components * SIZEOF(jpeg_component_info)); 284 } 285 286 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 287 ci++, compptr++) { 288 compptr->component_index = ci; 289 INPUT_BYTE(cinfo, compptr->component_id, return FALSE); 290 INPUT_BYTE(cinfo, c, return FALSE); 291 compptr->h_samp_factor = (c >> 4) & 15; 292 compptr->v_samp_factor = (c ) & 15; 293 INPUT_BYTE(cinfo, compptr->quant_tbl_no, return FALSE); 294 295 TRACEMS4(cinfo, 1, JTRC_SOF_COMPONENT, 296 compptr->component_id, compptr->h_samp_factor, 297 compptr->v_samp_factor, compptr->quant_tbl_no); 298 } 299 300 cinfo->marker->saw_SOF = TRUE; 301 302 INPUT_SYNC(cinfo); 303 return TRUE; 304} 305 306 307LOCAL(boolean) 308get_sos (j_decompress_ptr cinfo) 309/* Process a SOS marker */ 310{ 311 INT32 length; 312 int i, ci, n, c, cc; 313 jpeg_component_info * compptr; 314 INPUT_VARS(cinfo); 315 316 if (! cinfo->marker->saw_SOF) 317 ERREXIT(cinfo, JERR_SOS_NO_SOF); 318 319 INPUT_2BYTES(cinfo, length, return FALSE); 320 321 INPUT_BYTE(cinfo, n, return FALSE); /* Number of components */ 322 323 TRACEMS1(cinfo, 1, JTRC_SOS, n); 324 325 if (length != (n * 2 + 6) || n < 1 || n > MAX_COMPS_IN_SCAN) 326 ERREXIT(cinfo, JERR_BAD_LENGTH); 327 328 cinfo->comps_in_scan = n; 329 330 /* Collect the component-spec parameters */ 331 332 for (i = 0; i < n; i++) { 333 INPUT_BYTE(cinfo, cc, return FALSE); 334 INPUT_BYTE(cinfo, c, return FALSE); 335 336 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 337 ci++, compptr++) { 338 if (cc == compptr->component_id) 339 goto id_found; 340 } 341 342 ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc); 343 344 id_found: 345 346 cinfo->cur_comp_info[i] = compptr; 347 compptr->dc_tbl_no = (c >> 4) & 15; 348 compptr->ac_tbl_no = (c ) & 15; 349 350 TRACEMS3(cinfo, 1, JTRC_SOS_COMPONENT, cc, 351 compptr->dc_tbl_no, compptr->ac_tbl_no); 352 353 /* This CSi (cc) should differ from the previous CSi */ 354 for (ci = 0; ci < i; ci++) { 355 if (cinfo->cur_comp_info[ci] == compptr) 356 ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc); 357 } 358 } 359 360 /* Collect the additional scan parameters Ss, Se, Ah/Al. */ 361 INPUT_BYTE(cinfo, c, return FALSE); 362 cinfo->Ss = c; 363 INPUT_BYTE(cinfo, c, return FALSE); 364 cinfo->Se = c; 365 INPUT_BYTE(cinfo, c, return FALSE); 366 cinfo->Ah = (c >> 4) & 15; 367 cinfo->Al = (c ) & 15; 368 369 TRACEMS4(cinfo, 1, JTRC_SOS_PARAMS, cinfo->Ss, cinfo->Se, 370 cinfo->Ah, cinfo->Al); 371 372 /* Prepare to scan data & restart markers */ 373 cinfo->marker->next_restart_num = 0; 374 375 /* Count another SOS marker */ 376 cinfo->input_scan_number++; 377 378 INPUT_SYNC(cinfo); 379 return TRUE; 380} 381 382 383#ifdef D_ARITH_CODING_SUPPORTED 384 385LOCAL(boolean) 386get_dac (j_decompress_ptr cinfo) 387/* Process a DAC marker */ 388{ 389 INT32 length; 390 int index, val; 391 INPUT_VARS(cinfo); 392 393 INPUT_2BYTES(cinfo, length, return FALSE); 394 length -= 2; 395 396 while (length > 0) { 397 INPUT_BYTE(cinfo, index, return FALSE); 398 INPUT_BYTE(cinfo, val, return FALSE); 399 400 length -= 2; 401 402 TRACEMS2(cinfo, 1, JTRC_DAC, index, val); 403 404 if (index < 0 || index >= (2*NUM_ARITH_TBLS)) 405 ERREXIT1(cinfo, JERR_DAC_INDEX, index); 406 407 if (index >= NUM_ARITH_TBLS) { /* define AC table */ 408 cinfo->arith_ac_K[index-NUM_ARITH_TBLS] = (UINT8) val; 409 } else { /* define DC table */ 410 cinfo->arith_dc_L[index] = (UINT8) (val & 0x0F); 411 cinfo->arith_dc_U[index] = (UINT8) (val >> 4); 412 if (cinfo->arith_dc_L[index] > cinfo->arith_dc_U[index]) 413 ERREXIT1(cinfo, JERR_DAC_VALUE, val); 414 } 415 } 416 417 if (length != 0) 418 ERREXIT(cinfo, JERR_BAD_LENGTH); 419 420 INPUT_SYNC(cinfo); 421 return TRUE; 422} 423 424#else /* ! D_ARITH_CODING_SUPPORTED */ 425 426#define get_dac(cinfo) skip_variable(cinfo) 427 428#endif /* D_ARITH_CODING_SUPPORTED */ 429 430 431LOCAL(boolean) 432get_dht (j_decompress_ptr cinfo) 433/* Process a DHT marker */ 434{ 435 INT32 length; 436 UINT8 bits[17]; 437 UINT8 huffval[256]; 438 int i, index, count; 439 JHUFF_TBL **htblptr; 440 INPUT_VARS(cinfo); 441 442 INPUT_2BYTES(cinfo, length, return FALSE); 443 length -= 2; 444 445 while (length > 16) { 446 INPUT_BYTE(cinfo, index, return FALSE); 447 448 TRACEMS1(cinfo, 1, JTRC_DHT, index); 449 450 bits[0] = 0; 451 count = 0; 452 for (i = 1; i <= 16; i++) { 453 INPUT_BYTE(cinfo, bits[i], return FALSE); 454 count += bits[i]; 455 } 456 457 length -= 1 + 16; 458 459 TRACEMS8(cinfo, 2, JTRC_HUFFBITS, 460 bits[1], bits[2], bits[3], bits[4], 461 bits[5], bits[6], bits[7], bits[8]); 462 TRACEMS8(cinfo, 2, JTRC_HUFFBITS, 463 bits[9], bits[10], bits[11], bits[12], 464 bits[13], bits[14], bits[15], bits[16]); 465 466 /* Here we just do minimal validation of the counts to avoid walking 467 * off the end of our table space. jdhuff.c will check more carefully. 468 */ 469 if (count > 256 || ((INT32) count) > length) 470 ERREXIT(cinfo, JERR_BAD_HUFF_TABLE); 471 472 for (i = 0; i < count; i++) 473 INPUT_BYTE(cinfo, huffval[i], return FALSE); 474 475 length -= count; 476 477 if (index & 0x10) { /* AC table definition */ 478 index -= 0x10; 479 htblptr = &cinfo->ac_huff_tbl_ptrs[index]; 480 } else { /* DC table definition */ 481 htblptr = &cinfo->dc_huff_tbl_ptrs[index]; 482 } 483 484 if (index < 0 || index >= NUM_HUFF_TBLS) 485 ERREXIT1(cinfo, JERR_DHT_INDEX, index); 486 487 if (*htblptr == NULL) 488 *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo); 489 490 MEMCOPY((*htblptr)->bits, bits, SIZEOF((*htblptr)->bits)); 491 MEMCOPY((*htblptr)->huffval, huffval, SIZEOF((*htblptr)->huffval)); 492 } 493 494 if (length != 0) 495 ERREXIT(cinfo, JERR_BAD_LENGTH); 496 497 INPUT_SYNC(cinfo); 498 return TRUE; 499} 500 501 502LOCAL(boolean) 503get_dqt (j_decompress_ptr cinfo) 504/* Process a DQT marker */ 505{ 506 INT32 length; 507 int n, i, prec; 508 unsigned int tmp; 509 JQUANT_TBL *quant_ptr; 510 INPUT_VARS(cinfo); 511 512 INPUT_2BYTES(cinfo, length, return FALSE); 513 length -= 2; 514 515 while (length > 0) { 516 INPUT_BYTE(cinfo, n, return FALSE); 517 prec = n >> 4; 518 n &= 0x0F; 519 520 TRACEMS2(cinfo, 1, JTRC_DQT, n, prec); 521 522 if (n >= NUM_QUANT_TBLS) 523 ERREXIT1(cinfo, JERR_DQT_INDEX, n); 524 525 if (cinfo->quant_tbl_ptrs[n] == NULL) 526 cinfo->quant_tbl_ptrs[n] = jpeg_alloc_quant_table((j_common_ptr) cinfo); 527 quant_ptr = cinfo->quant_tbl_ptrs[n]; 528 529 for (i = 0; i < DCTSIZE2; i++) { 530 if (prec) 531 INPUT_2BYTES(cinfo, tmp, return FALSE); 532 else 533 INPUT_BYTE(cinfo, tmp, return FALSE); 534 /* We convert the zigzag-order table to natural array order. */ 535 quant_ptr->quantval[jpeg_natural_order[i]] = (UINT16) tmp; 536 } 537 538 if (cinfo->err->trace_level >= 2) { 539 for (i = 0; i < DCTSIZE2; i += 8) { 540 TRACEMS8(cinfo, 2, JTRC_QUANTVALS, 541 quant_ptr->quantval[i], quant_ptr->quantval[i+1], 542 quant_ptr->quantval[i+2], quant_ptr->quantval[i+3], 543 quant_ptr->quantval[i+4], quant_ptr->quantval[i+5], 544 quant_ptr->quantval[i+6], quant_ptr->quantval[i+7]); 545 } 546 } 547 548 length -= DCTSIZE2+1; 549 if (prec) length -= DCTSIZE2; 550 } 551 552 if (length != 0) 553 ERREXIT(cinfo, JERR_BAD_LENGTH); 554 555 INPUT_SYNC(cinfo); 556 return TRUE; 557} 558 559 560LOCAL(boolean) 561get_dri (j_decompress_ptr cinfo) 562/* Process a DRI marker */ 563{ 564 INT32 length; 565 unsigned int tmp; 566 INPUT_VARS(cinfo); 567 568 INPUT_2BYTES(cinfo, length, return FALSE); 569 570 if (length != 4) 571 ERREXIT(cinfo, JERR_BAD_LENGTH); 572 573 INPUT_2BYTES(cinfo, tmp, return FALSE); 574 575 TRACEMS1(cinfo, 1, JTRC_DRI, tmp); 576 577 cinfo->restart_interval = tmp; 578 579 INPUT_SYNC(cinfo); 580 return TRUE; 581} 582 583 584/* 585 * Routines for processing APPn and COM markers. 586 * These are either saved in memory or discarded, per application request. 587 * APP0 and APP14 are specially checked to see if they are 588 * JFIF and Adobe markers, respectively. 589 */ 590 591#define APP0_DATA_LEN 14 /* Length of interesting data in APP0 */ 592#define APP14_DATA_LEN 12 /* Length of interesting data in APP14 */ 593#define APPN_DATA_LEN 14 /* Must be the largest of the above!! */ 594 595 596LOCAL(void) 597examine_app0 (j_decompress_ptr cinfo, JOCTET FAR * data, 598 unsigned int datalen, INT32 remaining) 599/* Examine first few bytes from an APP0. 600 * Take appropriate action if it is a JFIF marker. 601 * datalen is # of bytes at data[], remaining is length of rest of marker data. 602 */ 603{ 604 INT32 totallen = (INT32) datalen + remaining; 605 606 if (datalen >= APP0_DATA_LEN && 607 GETJOCTET(data[0]) == 0x4A && 608 GETJOCTET(data[1]) == 0x46 && 609 GETJOCTET(data[2]) == 0x49 && 610 GETJOCTET(data[3]) == 0x46 && 611 GETJOCTET(data[4]) == 0) { 612 /* Found JFIF APP0 marker: save info */ 613 cinfo->saw_JFIF_marker = TRUE; 614 cinfo->JFIF_major_version = GETJOCTET(data[5]); 615 cinfo->JFIF_minor_version = GETJOCTET(data[6]); 616 cinfo->density_unit = GETJOCTET(data[7]); 617 cinfo->X_density = (GETJOCTET(data[8]) << 8) + GETJOCTET(data[9]); 618 cinfo->Y_density = (GETJOCTET(data[10]) << 8) + GETJOCTET(data[11]); 619 /* Check version. 620 * Major version must be 1, anything else signals an incompatible change. 621 * (We used to treat this as an error, but now it's a nonfatal warning, 622 * because some bozo at Hijaak couldn't read the spec.) 623 * Minor version should be 0..2, but process anyway if newer. 624 */ 625 if (cinfo->JFIF_major_version != 1) 626 WARNMS2(cinfo, JWRN_JFIF_MAJOR, 627 cinfo->JFIF_major_version, cinfo->JFIF_minor_version); 628 /* Generate trace messages */ 629 TRACEMS5(cinfo, 1, JTRC_JFIF, 630 cinfo->JFIF_major_version, cinfo->JFIF_minor_version, 631 cinfo->X_density, cinfo->Y_density, cinfo->density_unit); 632 /* Validate thumbnail dimensions and issue appropriate messages */ 633 if (GETJOCTET(data[12]) | GETJOCTET(data[13])) 634 TRACEMS2(cinfo, 1, JTRC_JFIF_THUMBNAIL, 635 GETJOCTET(data[12]), GETJOCTET(data[13])); 636 totallen -= APP0_DATA_LEN; 637 if (totallen != 638 ((INT32)GETJOCTET(data[12]) * (INT32)GETJOCTET(data[13]) * (INT32) 3)) 639 TRACEMS1(cinfo, 1, JTRC_JFIF_BADTHUMBNAILSIZE, (int) totallen); 640 } else if (datalen >= 6 && 641 GETJOCTET(data[0]) == 0x4A && 642 GETJOCTET(data[1]) == 0x46 && 643 GETJOCTET(data[2]) == 0x58 && 644 GETJOCTET(data[3]) == 0x58 && 645 GETJOCTET(data[4]) == 0) { 646 /* Found JFIF "JFXX" extension APP0 marker */ 647 /* The library doesn't actually do anything with these, 648 * but we try to produce a helpful trace message. 649 */ 650 switch (GETJOCTET(data[5])) { 651 case 0x10: 652 TRACEMS1(cinfo, 1, JTRC_THUMB_JPEG, (int) totallen); 653 break; 654 case 0x11: 655 TRACEMS1(cinfo, 1, JTRC_THUMB_PALETTE, (int) totallen); 656 break; 657 case 0x13: 658 TRACEMS1(cinfo, 1, JTRC_THUMB_RGB, (int) totallen); 659 break; 660 default: 661 TRACEMS2(cinfo, 1, JTRC_JFIF_EXTENSION, 662 GETJOCTET(data[5]), (int) totallen); 663 break; 664 } 665 } else { 666 /* Start of APP0 does not match "JFIF" or "JFXX", or too short */ 667 TRACEMS1(cinfo, 1, JTRC_APP0, (int) totallen); 668 669 /* 670 * In this case we have seen the APP0 marker but the remaining 671 * APP0 section may be corrupt. Regardless, we will set the 672 * saw_JFIF_marker flag as it is important for making the 673 * correct choice of JPEG color space later (we will assume 674 * YCbCr in this case). The version and density fields will 675 * contain default values, which should be sufficient for our needs. 676 */ 677 cinfo->saw_JFIF_marker = TRUE; 678 } 679} 680 681 682LOCAL(void) 683examine_app14 (j_decompress_ptr cinfo, JOCTET FAR * data, 684 unsigned int datalen, INT32 remaining) 685/* Examine first few bytes from an APP14. 686 * Take appropriate action if it is an Adobe marker. 687 * datalen is # of bytes at data[], remaining is length of rest of marker data. 688 */ 689{ 690 unsigned int version, flags0, flags1, transform; 691 692 if (datalen >= APP14_DATA_LEN && 693 GETJOCTET(data[0]) == 0x41 && 694 GETJOCTET(data[1]) == 0x64 && 695 GETJOCTET(data[2]) == 0x6F && 696 GETJOCTET(data[3]) == 0x62 && 697 GETJOCTET(data[4]) == 0x65) { 698 /* Found Adobe APP14 marker */ 699 version = (GETJOCTET(data[5]) << 8) + GETJOCTET(data[6]); 700 flags0 = (GETJOCTET(data[7]) << 8) + GETJOCTET(data[8]); 701 flags1 = (GETJOCTET(data[9]) << 8) + GETJOCTET(data[10]); 702 transform = GETJOCTET(data[11]); 703 TRACEMS4(cinfo, 1, JTRC_ADOBE, version, flags0, flags1, transform); 704 cinfo->saw_Adobe_marker = TRUE; 705 cinfo->Adobe_transform = (UINT8) transform; 706 } else { 707 /* Start of APP14 does not match "Adobe", or too short */ 708 TRACEMS1(cinfo, 1, JTRC_APP14, (int) (datalen + remaining)); 709 } 710} 711 712 713METHODDEF(boolean) 714get_interesting_appn (j_decompress_ptr cinfo) 715/* Process an APP0 or APP14 marker without saving it */ 716{ 717 INT32 length; 718 JOCTET b[APPN_DATA_LEN]; 719 unsigned int i, numtoread; 720 INPUT_VARS(cinfo); 721 722 INPUT_2BYTES(cinfo, length, return FALSE); 723 length -= 2; 724 725 /* get the interesting part of the marker data */ 726 if (length >= APPN_DATA_LEN) 727 numtoread = APPN_DATA_LEN; 728 else if (length > 0) 729 numtoread = (unsigned int) length; 730 else 731 numtoread = 0; 732 for (i = 0; i < numtoread; i++) 733 INPUT_BYTE(cinfo, b[i], return FALSE); 734 length -= numtoread; 735 736 /* process it */ 737 switch (cinfo->unread_marker) { 738 case M_APP0: 739 examine_app0(cinfo, (JOCTET FAR *) b, numtoread, length); 740 break; 741 case M_APP14: 742 examine_app14(cinfo, (JOCTET FAR *) b, numtoread, length); 743 break; 744 default: 745 /* can't get here unless jpeg_save_markers chooses wrong processor */ 746 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker); 747 break; 748 } 749 750 /* skip any remaining data -- could be lots */ 751 INPUT_SYNC(cinfo); 752 if (length > 0) 753 (*cinfo->src->skip_input_data) (cinfo, (long) length); 754 755 return TRUE; 756} 757 758 759#ifdef SAVE_MARKERS_SUPPORTED 760 761METHODDEF(boolean) 762save_marker (j_decompress_ptr cinfo) 763/* Save an APPn or COM marker into the marker list */ 764{ 765 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 766 jpeg_saved_marker_ptr cur_marker = marker->cur_marker; 767 unsigned int bytes_read, data_length; 768 JOCTET FAR * data; 769 INT32 length = 0; 770 INPUT_VARS(cinfo); 771 772 if (cur_marker == NULL) { 773 /* begin reading a marker */ 774 INPUT_2BYTES(cinfo, length, return FALSE); 775 length -= 2; 776 if (length >= 0) { /* watch out for bogus length word */ 777 /* figure out how much we want to save */ 778 unsigned int limit; 779 if (cinfo->unread_marker == (int) M_COM) 780 limit = marker->length_limit_COM; 781 else 782 limit = marker->length_limit_APPn[cinfo->unread_marker - (int) M_APP0]; 783 if ((unsigned int) length < limit) 784 limit = (unsigned int) length; 785 /* allocate and initialize the marker item */ 786 cur_marker = (jpeg_saved_marker_ptr) 787 (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE, 788 SIZEOF(struct jpeg_marker_struct) + limit); 789 cur_marker->next = NULL; 790 cur_marker->marker = (UINT8) cinfo->unread_marker; 791 cur_marker->original_length = (unsigned int) length; 792 cur_marker->data_length = limit; 793 /* data area is just beyond the jpeg_marker_struct */ 794 data = cur_marker->data = (JOCTET FAR *) (cur_marker + 1); 795 marker->cur_marker = cur_marker; 796 marker->bytes_read = 0; 797 bytes_read = 0; 798 data_length = limit; 799 } else { 800 /* deal with bogus length word */ 801 bytes_read = data_length = 0; 802 data = NULL; 803 } 804 } else { 805 /* resume reading a marker */ 806 bytes_read = marker->bytes_read; 807 data_length = cur_marker->data_length; 808 data = cur_marker->data + bytes_read; 809 } 810 811 while (bytes_read < data_length) { 812 INPUT_SYNC(cinfo); /* move the restart point to here */ 813 marker->bytes_read = bytes_read; 814 /* If there's not at least one byte in buffer, suspend */ 815 MAKE_BYTE_AVAIL(cinfo, return FALSE); 816 /* Copy bytes with reasonable rapidity */ 817 while (bytes_read < data_length && bytes_in_buffer > 0) { 818 *data++ = *next_input_byte++; 819 bytes_in_buffer--; 820 bytes_read++; 821 } 822 } 823 824 /* Done reading what we want to read */ 825 if (cur_marker != NULL) { /* will be NULL if bogus length word */ 826 /* Add new marker to end of list */ 827 if (cinfo->marker_list == NULL) { 828 cinfo->marker_list = cur_marker; 829 } else { 830 jpeg_saved_marker_ptr prev = cinfo->marker_list; 831 while (prev->next != NULL) 832 prev = prev->next; 833 prev->next = cur_marker; 834 } 835 /* Reset pointer & calc remaining data length */ 836 data = cur_marker->data; 837 length = cur_marker->original_length - data_length; 838 } 839 /* Reset to initial state for next marker */ 840 marker->cur_marker = NULL; 841 842 /* Process the marker if interesting; else just make a generic trace msg */ 843 switch (cinfo->unread_marker) { 844 case M_APP0: 845 examine_app0(cinfo, data, data_length, length); 846 break; 847 case M_APP14: 848 examine_app14(cinfo, data, data_length, length); 849 break; 850 default: 851 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, 852 (int) (data_length + length)); 853 break; 854 } 855 856 /* skip any remaining data -- could be lots */ 857 INPUT_SYNC(cinfo); /* do before skip_input_data */ 858 if (length > 0) 859 (*cinfo->src->skip_input_data) (cinfo, (long) length); 860 861 return TRUE; 862} 863 864#endif /* SAVE_MARKERS_SUPPORTED */ 865 866 867METHODDEF(boolean) 868skip_variable (j_decompress_ptr cinfo) 869/* Skip over an unknown or uninteresting variable-length marker */ 870{ 871 INT32 length; 872 INPUT_VARS(cinfo); 873 874 INPUT_2BYTES(cinfo, length, return FALSE); 875 length -= 2; 876 877 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, (int) length); 878 879 INPUT_SYNC(cinfo); /* do before skip_input_data */ 880 if (length > 0) 881 (*cinfo->src->skip_input_data) (cinfo, (long) length); 882 883 return TRUE; 884} 885 886 887/* 888 * Find the next JPEG marker, save it in cinfo->unread_marker. 889 * Returns FALSE if had to suspend before reaching a marker; 890 * in that case cinfo->unread_marker is unchanged. 891 * 892 * Note that the result might not be a valid marker code, 893 * but it will never be 0 or FF. 894 */ 895 896LOCAL(boolean) 897next_marker (j_decompress_ptr cinfo) 898{ 899 int c; 900 INPUT_VARS(cinfo); 901 902 for (;;) { 903 INPUT_BYTE(cinfo, c, return FALSE); 904 /* Skip any non-FF bytes. 905 * This may look a bit inefficient, but it will not occur in a valid file. 906 * We sync after each discarded byte so that a suspending data source 907 * can discard the byte from its buffer. 908 */ 909 while (c != 0xFF) { 910 cinfo->marker->discarded_bytes++; 911 INPUT_SYNC(cinfo); 912 INPUT_BYTE(cinfo, c, return FALSE); 913 } 914 /* This loop swallows any duplicate FF bytes. Extra FFs are legal as 915 * pad bytes, so don't count them in discarded_bytes. We assume there 916 * will not be so many consecutive FF bytes as to overflow a suspending 917 * data source's input buffer. 918 */ 919 do { 920 INPUT_BYTE(cinfo, c, return FALSE); 921 } while (c == 0xFF); 922 if (c != 0) 923 break; /* found a valid marker, exit loop */ 924 /* Reach here if we found a stuffed-zero data sequence (FF/00). 925 * Discard it and loop back to try again. 926 */ 927 cinfo->marker->discarded_bytes += 2; 928 INPUT_SYNC(cinfo); 929 } 930 931 if (cinfo->marker->discarded_bytes != 0) { 932 WARNMS2(cinfo, JWRN_EXTRANEOUS_DATA, cinfo->marker->discarded_bytes, c); 933 cinfo->marker->discarded_bytes = 0; 934 } 935 936 cinfo->unread_marker = c; 937 938 INPUT_SYNC(cinfo); 939 return TRUE; 940} 941 942 943LOCAL(boolean) 944first_marker (j_decompress_ptr cinfo) 945/* Like next_marker, but used to obtain the initial SOI marker. */ 946/* For this marker, we do not allow preceding garbage or fill; otherwise, 947 * we might well scan an entire input file before realizing it ain't JPEG. 948 * If an application wants to process non-JFIF files, it must seek to the 949 * SOI before calling the JPEG library. 950 */ 951{ 952 int c, c2; 953 INPUT_VARS(cinfo); 954 955 INPUT_BYTE(cinfo, c, return FALSE); 956 INPUT_BYTE(cinfo, c2, return FALSE); 957 if (c != 0xFF || c2 != (int) M_SOI) 958 ERREXIT2(cinfo, JERR_NO_SOI, c, c2); 959 960 cinfo->unread_marker = c2; 961 962 INPUT_SYNC(cinfo); 963 return TRUE; 964} 965 966 967/* 968 * Read markers until SOS or EOI. 969 * 970 * Returns same codes as are defined for jpeg_consume_input: 971 * JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI. 972 */ 973 974METHODDEF(int) 975read_markers (j_decompress_ptr cinfo) 976{ 977 /* Outer loop repeats once for each marker. */ 978 for (;;) { 979 /* Collect the marker proper, unless we already did. */ 980 /* NB: first_marker() enforces the requirement that SOI appear first. */ 981 if (cinfo->unread_marker == 0) { 982 if (! cinfo->marker->saw_SOI) { 983 if (! first_marker(cinfo)) 984 return JPEG_SUSPENDED; 985 } else { 986 if (! next_marker(cinfo)) 987 return JPEG_SUSPENDED; 988 } 989 } 990 /* At this point cinfo->unread_marker contains the marker code and the 991 * input point is just past the marker proper, but before any parameters. 992 * A suspension will cause us to return with this state still true. 993 */ 994 switch (cinfo->unread_marker) { 995 case M_SOI: 996 if (! get_soi(cinfo)) 997 return JPEG_SUSPENDED; 998 break; 999 1000 case M_SOF0: /* Baseline */ 1001 case M_SOF1: /* Extended sequential, Huffman */ 1002 if (! get_sof(cinfo, FALSE, FALSE)) 1003 return JPEG_SUSPENDED; 1004 break; 1005 1006 case M_SOF2: /* Progressive, Huffman */ 1007 if (! get_sof(cinfo, TRUE, FALSE)) 1008 return JPEG_SUSPENDED; 1009 break; 1010 1011 case M_SOF9: /* Extended sequential, arithmetic */ 1012 if (! get_sof(cinfo, FALSE, TRUE)) 1013 return JPEG_SUSPENDED; 1014 break; 1015 1016 case M_SOF10: /* Progressive, arithmetic */ 1017 if (! get_sof(cinfo, TRUE, TRUE)) 1018 return JPEG_SUSPENDED; 1019 break; 1020 1021 /* Currently unsupported SOFn types */ 1022 case M_SOF3: /* Lossless, Huffman */ 1023 case M_SOF5: /* Differential sequential, Huffman */ 1024 case M_SOF6: /* Differential progressive, Huffman */ 1025 case M_SOF7: /* Differential lossless, Huffman */ 1026 case M_JPG: /* Reserved for JPEG extensions */ 1027 case M_SOF11: /* Lossless, arithmetic */ 1028 case M_SOF13: /* Differential sequential, arithmetic */ 1029 case M_SOF14: /* Differential progressive, arithmetic */ 1030 case M_SOF15: /* Differential lossless, arithmetic */ 1031 ERREXIT1(cinfo, JERR_SOF_UNSUPPORTED, cinfo->unread_marker); 1032 break; 1033 1034 case M_SOS: 1035 if (! get_sos(cinfo)) 1036 return JPEG_SUSPENDED; 1037 cinfo->unread_marker = 0; /* processed the marker */ 1038 return JPEG_REACHED_SOS; 1039 1040 case M_EOI: 1041 TRACEMS(cinfo, 1, JTRC_EOI); 1042 cinfo->unread_marker = 0; /* processed the marker */ 1043 return JPEG_REACHED_EOI; 1044 1045 case M_DAC: 1046 if (! get_dac(cinfo)) 1047 return JPEG_SUSPENDED; 1048 break; 1049 1050 case M_DHT: 1051 if (! get_dht(cinfo)) 1052 return JPEG_SUSPENDED; 1053 break; 1054 1055 case M_DQT: 1056 if (! get_dqt(cinfo)) 1057 return JPEG_SUSPENDED; 1058 break; 1059 1060 case M_DRI: 1061 if (! get_dri(cinfo)) 1062 return JPEG_SUSPENDED; 1063 break; 1064 1065 case M_APP0: 1066 case M_APP1: 1067 case M_APP2: 1068 case M_APP3: 1069 case M_APP4: 1070 case M_APP5: 1071 case M_APP6: 1072 case M_APP7: 1073 case M_APP8: 1074 case M_APP9: 1075 case M_APP10: 1076 case M_APP11: 1077 case M_APP12: 1078 case M_APP13: 1079 case M_APP14: 1080 case M_APP15: 1081 if (! (*((my_marker_ptr) cinfo->marker)->process_APPn[ 1082 cinfo->unread_marker - (int) M_APP0]) (cinfo)) 1083 return JPEG_SUSPENDED; 1084 break; 1085 1086 case M_COM: 1087 if (! (*((my_marker_ptr) cinfo->marker)->process_COM) (cinfo)) 1088 return JPEG_SUSPENDED; 1089 break; 1090 1091 case M_RST0: /* these are all parameterless */ 1092 case M_RST1: 1093 case M_RST2: 1094 case M_RST3: 1095 case M_RST4: 1096 case M_RST5: 1097 case M_RST6: 1098 case M_RST7: 1099 case M_TEM: 1100 TRACEMS1(cinfo, 1, JTRC_PARMLESS_MARKER, cinfo->unread_marker); 1101 break; 1102 1103 case M_DNL: /* Ignore DNL ... perhaps the wrong thing */ 1104 if (! skip_variable(cinfo)) 1105 return JPEG_SUSPENDED; 1106 break; 1107 1108 default: /* must be DHP, EXP, JPGn, or RESn */ 1109 /* For now, we treat the reserved markers as fatal errors since they are 1110 * likely to be used to signal incompatible JPEG Part 3 extensions. 1111 * Once the JPEG 3 version-number marker is well defined, this code 1112 * ought to change! 1113 * [To be behaviorally compatible with other popular image display 1114 * applications, we are now treating these unknown markers as warnings, 1115 * rather than errors. This allows processing to continue, although 1116 * any portions of the image after the bad marker may be corrupted 1117 * and/or rendered gray. See 4511441.] 1118 */ 1119 WARNMS1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker); 1120 break; 1121 } 1122 /* Successfully processed marker, so reset state variable */ 1123 cinfo->unread_marker = 0; 1124 } /* end loop */ 1125} 1126 1127 1128/* 1129 * Read a restart marker, which is expected to appear next in the datastream; 1130 * if the marker is not there, take appropriate recovery action. 1131 * Returns FALSE if suspension is required. 1132 * 1133 * This is called by the entropy decoder after it has read an appropriate 1134 * number of MCUs. cinfo->unread_marker may be nonzero if the entropy decoder 1135 * has already read a marker from the data source. Under normal conditions 1136 * cinfo->unread_marker will be reset to 0 before returning; if not reset, 1137 * it holds a marker which the decoder will be unable to read past. 1138 */ 1139 1140METHODDEF(boolean) 1141read_restart_marker (j_decompress_ptr cinfo) 1142{ 1143 /* Obtain a marker unless we already did. */ 1144 /* Note that next_marker will complain if it skips any data. */ 1145 if (cinfo->unread_marker == 0) { 1146 if (! next_marker(cinfo)) 1147 return FALSE; 1148 } 1149 1150 if (cinfo->unread_marker == 1151 ((int) M_RST0 + cinfo->marker->next_restart_num)) { 1152 /* Normal case --- swallow the marker and let entropy decoder continue */ 1153 TRACEMS1(cinfo, 3, JTRC_RST, cinfo->marker->next_restart_num); 1154 cinfo->unread_marker = 0; 1155 } else { 1156 /* Uh-oh, the restart markers have been messed up. */ 1157 /* Let the data source manager determine how to resync. */ 1158 if (! (*cinfo->src->resync_to_restart) (cinfo, 1159 cinfo->marker->next_restart_num)) 1160 return FALSE; 1161 } 1162 1163 /* Update next-restart state */ 1164 cinfo->marker->next_restart_num = (cinfo->marker->next_restart_num + 1) & 7; 1165 1166 return TRUE; 1167} 1168 1169 1170/* 1171 * This is the default resync_to_restart method for data source managers 1172 * to use if they don't have any better approach. Some data source managers 1173 * may be able to back up, or may have additional knowledge about the data 1174 * which permits a more intelligent recovery strategy; such managers would 1175 * presumably supply their own resync method. 1176 * 1177 * read_restart_marker calls resync_to_restart if it finds a marker other than 1178 * the restart marker it was expecting. (This code is *not* used unless 1179 * a nonzero restart interval has been declared.) cinfo->unread_marker is 1180 * the marker code actually found (might be anything, except 0 or FF). 1181 * The desired restart marker number (0..7) is passed as a parameter. 1182 * This routine is supposed to apply whatever error recovery strategy seems 1183 * appropriate in order to position the input stream to the next data segment. 1184 * Note that cinfo->unread_marker is treated as a marker appearing before 1185 * the current data-source input point; usually it should be reset to zero 1186 * before returning. 1187 * Returns FALSE if suspension is required. 1188 * 1189 * This implementation is substantially constrained by wanting to treat the 1190 * input as a data stream; this means we can't back up. Therefore, we have 1191 * only the following actions to work with: 1192 * 1. Simply discard the marker and let the entropy decoder resume at next 1193 * byte of file. 1194 * 2. Read forward until we find another marker, discarding intervening 1195 * data. (In theory we could look ahead within the current bufferload, 1196 * without having to discard data if we don't find the desired marker. 1197 * This idea is not implemented here, in part because it makes behavior 1198 * dependent on buffer size and chance buffer-boundary positions.) 1199 * 3. Leave the marker unread (by failing to zero cinfo->unread_marker). 1200 * This will cause the entropy decoder to process an empty data segment, 1201 * inserting dummy zeroes, and then we will reprocess the marker. 1202 * 1203 * #2 is appropriate if we think the desired marker lies ahead, while #3 is 1204 * appropriate if the found marker is a future restart marker (indicating 1205 * that we have missed the desired restart marker, probably because it got 1206 * corrupted). 1207 * We apply #2 or #3 if the found marker is a restart marker no more than 1208 * two counts behind or ahead of the expected one. We also apply #2 if the 1209 * found marker is not a legal JPEG marker code (it's certainly bogus data). 1210 * If the found marker is a restart marker more than 2 counts away, we do #1 1211 * (too much risk that the marker is erroneous; with luck we will be able to 1212 * resync at some future point). 1213 * For any valid non-restart JPEG marker, we apply #3. This keeps us from 1214 * overrunning the end of a scan. An implementation limited to single-scan 1215 * files might find it better to apply #2 for markers other than EOI, since 1216 * any other marker would have to be bogus data in that case. 1217 */ 1218 1219GLOBAL(boolean) 1220jpeg_resync_to_restart (j_decompress_ptr cinfo, int desired) 1221{ 1222 int marker = cinfo->unread_marker; 1223 int action = 1; 1224 1225 /* Always put up a warning. */ 1226 WARNMS2(cinfo, JWRN_MUST_RESYNC, marker, desired); 1227 1228 /* Outer loop handles repeated decision after scanning forward. */ 1229 for (;;) { 1230 if (marker < (int) M_SOF0) 1231 action = 2; /* invalid marker */ 1232 else if (marker < (int) M_RST0 || marker > (int) M_RST7) 1233 action = 3; /* valid non-restart marker */ 1234 else { 1235 if (marker == ((int) M_RST0 + ((desired+1) & 7)) || 1236 marker == ((int) M_RST0 + ((desired+2) & 7))) 1237 action = 3; /* one of the next two expected restarts */ 1238 else if (marker == ((int) M_RST0 + ((desired-1) & 7)) || 1239 marker == ((int) M_RST0 + ((desired-2) & 7))) 1240 action = 2; /* a prior restart, so advance */ 1241 else 1242 action = 1; /* desired restart or too far away */ 1243 } 1244 TRACEMS2(cinfo, 4, JTRC_RECOVERY_ACTION, marker, action); 1245 switch (action) { 1246 case 1: 1247 /* Discard marker and let entropy decoder resume processing. */ 1248 cinfo->unread_marker = 0; 1249 return TRUE; 1250 case 2: 1251 /* Scan to the next marker, and repeat the decision loop. */ 1252 if (! next_marker(cinfo)) 1253 return FALSE; 1254 marker = cinfo->unread_marker; 1255 break; 1256 case 3: 1257 /* Return without advancing past this marker. */ 1258 /* Entropy decoder will be forced to process an empty segment. */ 1259 return TRUE; 1260 } 1261 } /* end loop */ 1262} 1263 1264 1265/* 1266 * Reset marker processing state to begin a fresh datastream. 1267 */ 1268 1269METHODDEF(void) 1270reset_marker_reader (j_decompress_ptr cinfo) 1271{ 1272 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 1273 1274 cinfo->comp_info = NULL; /* until allocated by get_sof */ 1275 cinfo->input_scan_number = 0; /* no SOS seen yet */ 1276 cinfo->unread_marker = 0; /* no pending marker */ 1277 marker->pub.saw_SOI = FALSE; /* set internal state too */ 1278 marker->pub.saw_SOF = FALSE; 1279 marker->pub.discarded_bytes = 0; 1280 marker->cur_marker = NULL; 1281} 1282 1283 1284/* 1285 * Initialize the marker reader module. 1286 * This is called only once, when the decompression object is created. 1287 */ 1288 1289GLOBAL(void) 1290jinit_marker_reader (j_decompress_ptr cinfo) 1291{ 1292 my_marker_ptr marker; 1293 int i; 1294 1295 /* Create subobject in permanent pool */ 1296 marker = (my_marker_ptr) 1297 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT, 1298 SIZEOF(my_marker_reader)); 1299 cinfo->marker = (struct jpeg_marker_reader *) marker; 1300 /* Initialize public method pointers */ 1301 marker->pub.reset_marker_reader = reset_marker_reader; 1302 marker->pub.read_markers = read_markers; 1303 marker->pub.read_restart_marker = read_restart_marker; 1304 /* Initialize COM/APPn processing. 1305 * By default, we examine and then discard APP0 and APP14. 1306 * We also may need to save APP1 to detect the case of EXIF images (see 4881314). 1307 * COM and all other APPn are simply discarded. 1308 */ 1309 marker->process_COM = skip_variable; 1310 marker->length_limit_COM = 0; 1311 for (i = 0; i < 16; i++) { 1312 marker->process_APPn[i] = skip_variable; 1313 marker->length_limit_APPn[i] = 0; 1314 } 1315 marker->process_APPn[0] = get_interesting_appn; 1316 marker->process_APPn[1] = save_marker; 1317 marker->process_APPn[14] = get_interesting_appn; 1318 /* Reset marker processing state */ 1319 reset_marker_reader(cinfo); 1320} 1321 1322 1323/* 1324 * Control saving of COM and APPn markers into marker_list. 1325 */ 1326 1327#ifdef SAVE_MARKERS_SUPPORTED 1328 1329GLOBAL(void) 1330jpeg_save_markers (j_decompress_ptr cinfo, int marker_code, 1331 unsigned int length_limit) 1332{ 1333 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 1334 size_t maxlength; 1335 jpeg_marker_parser_method processor; 1336 1337 /* Length limit mustn't be larger than what we can allocate 1338 * (should only be a concern in a 16-bit environment). 1339 */ 1340 maxlength = cinfo->mem->max_alloc_chunk - SIZEOF(struct jpeg_marker_struct); 1341 if (length_limit > maxlength) 1342 length_limit = (unsigned int) maxlength; 1343 1344 /* Choose processor routine to use. 1345 * APP0/APP14 have special requirements. 1346 */ 1347 if (length_limit) { 1348 processor = save_marker; 1349 /* If saving APP0/APP14, save at least enough for our internal use. */ 1350 if (marker_code == (int) M_APP0 && length_limit < APP0_DATA_LEN) 1351 length_limit = APP0_DATA_LEN; 1352 else if (marker_code == (int) M_APP14 && length_limit < APP14_DATA_LEN) 1353 length_limit = APP14_DATA_LEN; 1354 } else { 1355 processor = skip_variable; 1356 /* If discarding APP0/APP14, use our regular on-the-fly processor. */ 1357 if (marker_code == (int) M_APP0 || marker_code == (int) M_APP14) 1358 processor = get_interesting_appn; 1359 } 1360 1361 if (marker_code == (int) M_COM) { 1362 marker->process_COM = processor; 1363 marker->length_limit_COM = length_limit; 1364 } else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15) { 1365 marker->process_APPn[marker_code - (int) M_APP0] = processor; 1366 marker->length_limit_APPn[marker_code - (int) M_APP0] = length_limit; 1367 } else 1368 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code); 1369} 1370 1371#endif /* SAVE_MARKERS_SUPPORTED */ 1372 1373 1374/* 1375 * Install a special processing method for COM or APPn markers. 1376 */ 1377 1378GLOBAL(void) 1379jpeg_set_marker_processor (j_decompress_ptr cinfo, int marker_code, 1380 jpeg_marker_parser_method routine) 1381{ 1382 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 1383 1384 if (marker_code == (int) M_COM) 1385 marker->process_COM = routine; 1386 else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15) 1387 marker->process_APPn[marker_code - (int) M_APP0] = routine; 1388 else 1389 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code); 1390} 1391