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