jdmarker.c (42610B)
1 /* 2 * jdmarker.c 3 * 4 * This file was part of the Independent JPEG Group's software: 5 * Copyright (C) 1991-1998, Thomas G. Lane. 6 * Lossless JPEG Modifications: 7 * Copyright (C) 1999, Ken Murchison. 8 * libjpeg-turbo Modifications: 9 * Copyright (C) 2012, 2015, 2022, 2024, D. R. Commander. 10 * For conditions of distribution and use, see the accompanying README.ijg 11 * file. 12 * 13 * This file contains routines to decode JPEG datastream markers. 14 * Most of the complexity arises from our desire to support input 15 * suspension: if not all of the data for a marker is available, 16 * we must exit back to the application. On resumption, we reprocess 17 * the marker. 18 */ 19 20 #define JPEG_INTERNALS 21 #include "jinclude.h" 22 #include "jpeglib.h" 23 24 25 typedef enum { /* JPEG marker codes */ 26 M_SOF0 = 0xc0, 27 M_SOF1 = 0xc1, 28 M_SOF2 = 0xc2, 29 M_SOF3 = 0xc3, 30 31 M_SOF5 = 0xc5, 32 M_SOF6 = 0xc6, 33 M_SOF7 = 0xc7, 34 35 M_JPG = 0xc8, 36 M_SOF9 = 0xc9, 37 M_SOF10 = 0xca, 38 M_SOF11 = 0xcb, 39 40 M_SOF13 = 0xcd, 41 M_SOF14 = 0xce, 42 M_SOF15 = 0xcf, 43 44 M_DHT = 0xc4, 45 46 M_DAC = 0xcc, 47 48 M_RST0 = 0xd0, 49 M_RST1 = 0xd1, 50 M_RST2 = 0xd2, 51 M_RST3 = 0xd3, 52 M_RST4 = 0xd4, 53 M_RST5 = 0xd5, 54 M_RST6 = 0xd6, 55 M_RST7 = 0xd7, 56 57 M_SOI = 0xd8, 58 M_EOI = 0xd9, 59 M_SOS = 0xda, 60 M_DQT = 0xdb, 61 M_DNL = 0xdc, 62 M_DRI = 0xdd, 63 M_DHP = 0xde, 64 M_EXP = 0xdf, 65 66 M_APP0 = 0xe0, 67 M_APP1 = 0xe1, 68 M_APP2 = 0xe2, 69 M_APP3 = 0xe3, 70 M_APP4 = 0xe4, 71 M_APP5 = 0xe5, 72 M_APP6 = 0xe6, 73 M_APP7 = 0xe7, 74 M_APP8 = 0xe8, 75 M_APP9 = 0xe9, 76 M_APP10 = 0xea, 77 M_APP11 = 0xeb, 78 M_APP12 = 0xec, 79 M_APP13 = 0xed, 80 M_APP14 = 0xee, 81 M_APP15 = 0xef, 82 83 M_JPG0 = 0xf0, 84 M_JPG13 = 0xfd, 85 M_COM = 0xfe, 86 87 M_TEM = 0x01, 88 89 M_ERROR = 0x100 90 } JPEG_MARKER; 91 92 93 /* Private state */ 94 95 typedef struct { 96 struct jpeg_marker_reader pub; /* public fields */ 97 98 /* Application-overridable marker processing methods */ 99 jpeg_marker_parser_method process_COM; 100 jpeg_marker_parser_method process_APPn[16]; 101 102 /* Limit on marker data length to save for each marker type */ 103 unsigned int length_limit_COM; 104 unsigned int length_limit_APPn[16]; 105 106 /* Status of COM/APPn marker saving */ 107 jpeg_saved_marker_ptr cur_marker; /* NULL if not processing a marker */ 108 unsigned int bytes_read; /* data bytes read so far in marker */ 109 /* Note: cur_marker is not linked into marker_list until it's all read. */ 110 } my_marker_reader; 111 112 typedef my_marker_reader *my_marker_ptr; 113 114 115 /* 116 * Macros for fetching data from the data source module. 117 * 118 * At all times, cinfo->src->next_input_byte and ->bytes_in_buffer reflect 119 * the current restart point; we update them only when we have reached a 120 * suitable place to restart if a suspension occurs. 121 */ 122 123 /* Declare and initialize local copies of input pointer/count */ 124 #define INPUT_VARS(cinfo) \ 125 struct jpeg_source_mgr *datasrc = (cinfo)->src; \ 126 const JOCTET *next_input_byte = datasrc->next_input_byte; \ 127 size_t bytes_in_buffer = datasrc->bytes_in_buffer 128 129 /* Unload the local copies --- do this only at a restart boundary */ 130 #define INPUT_SYNC(cinfo) \ 131 ( datasrc->next_input_byte = next_input_byte, \ 132 datasrc->bytes_in_buffer = bytes_in_buffer ) 133 134 /* Reload the local copies --- used only in MAKE_BYTE_AVAIL */ 135 #define INPUT_RELOAD(cinfo) \ 136 ( next_input_byte = datasrc->next_input_byte, \ 137 bytes_in_buffer = datasrc->bytes_in_buffer ) 138 139 /* Internal macro for INPUT_BYTE and INPUT_2BYTES: make a byte available. 140 * Note we do *not* do INPUT_SYNC before calling fill_input_buffer, 141 * but we must reload the local copies after a successful fill. 142 */ 143 #define MAKE_BYTE_AVAIL(cinfo, action) \ 144 if (bytes_in_buffer == 0) { \ 145 if (!(*datasrc->fill_input_buffer) (cinfo)) \ 146 { action; } \ 147 INPUT_RELOAD(cinfo); \ 148 } 149 150 /* Read a byte into variable V. 151 * If must suspend, take the specified action (typically "return FALSE"). 152 */ 153 #define INPUT_BYTE(cinfo, V, action) \ 154 MAKESTMT( MAKE_BYTE_AVAIL(cinfo, action); \ 155 bytes_in_buffer--; \ 156 V = *next_input_byte++; ) 157 158 /* As above, but read two bytes interpreted as an unsigned 16-bit integer. 159 * V should be declared unsigned int or perhaps JLONG. 160 */ 161 #define INPUT_2BYTES(cinfo, V, action) \ 162 MAKESTMT( MAKE_BYTE_AVAIL(cinfo, action); \ 163 bytes_in_buffer--; \ 164 V = ((unsigned int)(*next_input_byte++)) << 8; \ 165 MAKE_BYTE_AVAIL(cinfo, action); \ 166 bytes_in_buffer--; \ 167 V += *next_input_byte++; ) 168 169 170 /* 171 * Routines to process JPEG markers. 172 * 173 * Entry condition: JPEG marker itself has been read and its code saved 174 * in cinfo->unread_marker; input restart point is just after the marker. 175 * 176 * Exit: if return TRUE, have read and processed any parameters, and have 177 * updated the restart point to point after the parameters. 178 * If return FALSE, was forced to suspend before reaching end of 179 * marker parameters; restart point has not been moved. Same routine 180 * will be called again after application supplies more input data. 181 * 182 * This approach to suspension assumes that all of a marker's parameters 183 * can fit into a single input bufferload. This should hold for "normal" 184 * markers. Some COM/APPn markers might have large parameter segments 185 * that might not fit. If we are simply dropping such a marker, we use 186 * skip_input_data to get past it, and thereby put the problem on the 187 * source manager's shoulders. If we are saving the marker's contents 188 * into memory, we use a slightly different convention: when forced to 189 * suspend, the marker processor updates the restart point to the end of 190 * what it's consumed (ie, the end of the buffer) before returning FALSE. 191 * On resumption, cinfo->unread_marker still contains the marker code, 192 * but the data source will point to the next chunk of marker data. 193 * The marker processor must retain internal state to deal with this. 194 * 195 * Note that we don't bother to avoid duplicate trace messages if a 196 * suspension occurs within marker parameters. Other side effects 197 * require more care. 198 */ 199 200 201 LOCAL(boolean) 202 get_soi(j_decompress_ptr cinfo) 203 /* Process an SOI marker */ 204 { 205 int i; 206 207 TRACEMS(cinfo, 1, JTRC_SOI); 208 209 if (cinfo->marker->saw_SOI) 210 ERREXIT(cinfo, JERR_SOI_DUPLICATE); 211 212 /* Reset all parameters that are defined to be reset by SOI */ 213 214 for (i = 0; i < NUM_ARITH_TBLS; i++) { 215 cinfo->arith_dc_L[i] = 0; 216 cinfo->arith_dc_U[i] = 1; 217 cinfo->arith_ac_K[i] = 5; 218 } 219 cinfo->restart_interval = 0; 220 221 /* Set initial assumptions for colorspace etc */ 222 223 cinfo->jpeg_color_space = JCS_UNKNOWN; 224 cinfo->CCIR601_sampling = FALSE; /* Assume non-CCIR sampling??? */ 225 226 cinfo->saw_JFIF_marker = FALSE; 227 cinfo->JFIF_major_version = 1; /* set default JFIF APP0 values */ 228 cinfo->JFIF_minor_version = 1; 229 cinfo->density_unit = 0; 230 cinfo->X_density = 1; 231 cinfo->Y_density = 1; 232 cinfo->saw_Adobe_marker = FALSE; 233 cinfo->Adobe_transform = 0; 234 235 cinfo->marker->saw_SOI = TRUE; 236 237 return TRUE; 238 } 239 240 241 LOCAL(boolean) 242 get_sof(j_decompress_ptr cinfo, boolean is_prog, boolean is_lossless, 243 boolean is_arith) 244 /* Process a SOFn marker */ 245 { 246 JLONG length; 247 int c, ci; 248 jpeg_component_info *compptr; 249 INPUT_VARS(cinfo); 250 251 if (cinfo->marker->saw_SOF) 252 ERREXIT(cinfo, JERR_SOF_DUPLICATE); 253 254 cinfo->progressive_mode = is_prog; 255 cinfo->master->lossless = is_lossless; 256 cinfo->arith_code = is_arith; 257 258 INPUT_2BYTES(cinfo, length, return FALSE); 259 260 INPUT_BYTE(cinfo, cinfo->data_precision, return FALSE); 261 INPUT_2BYTES(cinfo, cinfo->image_height, return FALSE); 262 INPUT_2BYTES(cinfo, cinfo->image_width, return FALSE); 263 INPUT_BYTE(cinfo, cinfo->num_components, return FALSE); 264 265 length -= 8; 266 267 TRACEMS4(cinfo, 1, JTRC_SOF, cinfo->unread_marker, 268 (int)cinfo->image_width, (int)cinfo->image_height, 269 cinfo->num_components); 270 271 /* We don't support files in which the image height is initially specified */ 272 /* as 0 and is later redefined by DNL. As long as we have to check that, */ 273 /* might as well have a general sanity check. */ 274 if (cinfo->image_height <= 0 || cinfo->image_width <= 0 || 275 cinfo->num_components <= 0) 276 ERREXIT(cinfo, JERR_EMPTY_IMAGE); 277 278 if (length != (cinfo->num_components * 3)) 279 ERREXIT(cinfo, JERR_BAD_LENGTH); 280 281 if (cinfo->comp_info == NULL) /* do only once, even if suspend */ 282 cinfo->comp_info = (jpeg_component_info *)(*cinfo->mem->alloc_small) 283 ((j_common_ptr)cinfo, JPOOL_IMAGE, 284 cinfo->num_components * sizeof(jpeg_component_info)); 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 } 305 306 307 LOCAL(boolean) 308 get_sos(j_decompress_ptr cinfo) 309 /* Process a SOS marker */ 310 { 311 JLONG length; 312 int i, ci, n, c, cc, pi; 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 < MAX_COMPS_IN_SCAN; i++) 333 cinfo->cur_comp_info[i] = NULL; 334 335 for (i = 0; i < n; i++) { 336 INPUT_BYTE(cinfo, cc, return FALSE); 337 INPUT_BYTE(cinfo, c, return FALSE); 338 339 for (ci = 0, compptr = cinfo->comp_info; 340 ci < cinfo->num_components && ci < MAX_COMPS_IN_SCAN; 341 ci++, compptr++) { 342 if (cc == compptr->component_id && !cinfo->cur_comp_info[ci]) 343 goto id_found; 344 } 345 346 ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc); 347 348 id_found: 349 350 cinfo->cur_comp_info[i] = compptr; 351 compptr->dc_tbl_no = (c >> 4) & 15; 352 compptr->ac_tbl_no = (c ) & 15; 353 354 TRACEMS3(cinfo, 1, JTRC_SOS_COMPONENT, cc, 355 compptr->dc_tbl_no, compptr->ac_tbl_no); 356 357 /* This CSi (cc) should differ from the previous CSi */ 358 for (pi = 0; pi < i; pi++) { 359 if (cinfo->cur_comp_info[pi] == compptr) { 360 ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc); 361 } 362 } 363 } 364 365 /* Collect the additional scan parameters Ss, Se, Ah/Al. */ 366 INPUT_BYTE(cinfo, c, return FALSE); 367 cinfo->Ss = c; 368 INPUT_BYTE(cinfo, c, return FALSE); 369 cinfo->Se = c; 370 INPUT_BYTE(cinfo, c, return FALSE); 371 cinfo->Ah = (c >> 4) & 15; 372 cinfo->Al = (c ) & 15; 373 374 TRACEMS4(cinfo, 1, JTRC_SOS_PARAMS, cinfo->Ss, cinfo->Se, 375 cinfo->Ah, cinfo->Al); 376 377 /* Prepare to scan data & restart markers */ 378 cinfo->marker->next_restart_num = 0; 379 380 /* Count another SOS marker */ 381 cinfo->input_scan_number++; 382 383 INPUT_SYNC(cinfo); 384 return TRUE; 385 } 386 387 388 #ifdef D_ARITH_CODING_SUPPORTED 389 390 LOCAL(boolean) 391 get_dac(j_decompress_ptr cinfo) 392 /* Process a DAC marker */ 393 { 394 JLONG length; 395 int index, val; 396 INPUT_VARS(cinfo); 397 398 INPUT_2BYTES(cinfo, length, return FALSE); 399 length -= 2; 400 401 while (length > 0) { 402 INPUT_BYTE(cinfo, index, return FALSE); 403 INPUT_BYTE(cinfo, val, return FALSE); 404 405 length -= 2; 406 407 TRACEMS2(cinfo, 1, JTRC_DAC, index, val); 408 409 if (index < 0 || index >= (2 * NUM_ARITH_TBLS)) 410 ERREXIT1(cinfo, JERR_DAC_INDEX, index); 411 412 if (index >= NUM_ARITH_TBLS) { /* define AC table */ 413 cinfo->arith_ac_K[index - NUM_ARITH_TBLS] = (UINT8)val; 414 } else { /* define DC table */ 415 cinfo->arith_dc_L[index] = (UINT8)(val & 0x0F); 416 cinfo->arith_dc_U[index] = (UINT8)(val >> 4); 417 if (cinfo->arith_dc_L[index] > cinfo->arith_dc_U[index]) 418 ERREXIT1(cinfo, JERR_DAC_VALUE, val); 419 } 420 } 421 422 if (length != 0) 423 ERREXIT(cinfo, JERR_BAD_LENGTH); 424 425 INPUT_SYNC(cinfo); 426 return TRUE; 427 } 428 429 #else /* !D_ARITH_CODING_SUPPORTED */ 430 431 #define get_dac(cinfo) skip_variable(cinfo) 432 433 #endif /* D_ARITH_CODING_SUPPORTED */ 434 435 436 LOCAL(boolean) 437 get_dht(j_decompress_ptr cinfo) 438 /* Process a DHT marker */ 439 { 440 JLONG length; 441 UINT8 bits[17]; 442 UINT8 huffval[256]; 443 int i, index, count; 444 JHUFF_TBL **htblptr; 445 INPUT_VARS(cinfo); 446 447 INPUT_2BYTES(cinfo, length, return FALSE); 448 length -= 2; 449 450 while (length > 16) { 451 INPUT_BYTE(cinfo, index, return FALSE); 452 453 TRACEMS1(cinfo, 1, JTRC_DHT, index); 454 455 bits[0] = 0; 456 count = 0; 457 for (i = 1; i <= 16; i++) { 458 INPUT_BYTE(cinfo, bits[i], return FALSE); 459 count += bits[i]; 460 } 461 462 length -= 1 + 16; 463 464 TRACEMS8(cinfo, 2, JTRC_HUFFBITS, 465 bits[1], bits[2], bits[3], bits[4], 466 bits[5], bits[6], bits[7], bits[8]); 467 TRACEMS8(cinfo, 2, JTRC_HUFFBITS, 468 bits[9], bits[10], bits[11], bits[12], 469 bits[13], bits[14], bits[15], bits[16]); 470 471 /* Here we just do minimal validation of the counts to avoid walking 472 * off the end of our table space. jdhuff.c will check more carefully. 473 */ 474 if (count > 256 || ((JLONG)count) > length) 475 ERREXIT(cinfo, JERR_BAD_HUFF_TABLE); 476 477 for (i = 0; i < count; i++) 478 INPUT_BYTE(cinfo, huffval[i], return FALSE); 479 480 memset(&huffval[count], 0, (256 - count) * sizeof(UINT8)); 481 482 length -= count; 483 484 if (index & 0x10) { /* AC table definition */ 485 index -= 0x10; 486 if (index < 0 || index >= NUM_HUFF_TBLS) 487 ERREXIT1(cinfo, JERR_DHT_INDEX, index); 488 htblptr = &cinfo->ac_huff_tbl_ptrs[index]; 489 } else { /* DC table definition */ 490 if (index < 0 || index >= NUM_HUFF_TBLS) 491 ERREXIT1(cinfo, JERR_DHT_INDEX, index); 492 htblptr = &cinfo->dc_huff_tbl_ptrs[index]; 493 } 494 495 if (*htblptr == NULL) 496 *htblptr = jpeg_alloc_huff_table((j_common_ptr)cinfo); 497 498 memcpy((*htblptr)->bits, bits, sizeof((*htblptr)->bits)); 499 memcpy((*htblptr)->huffval, huffval, sizeof((*htblptr)->huffval)); 500 } 501 502 if (length != 0) 503 ERREXIT(cinfo, JERR_BAD_LENGTH); 504 505 INPUT_SYNC(cinfo); 506 return TRUE; 507 } 508 509 510 LOCAL(boolean) 511 get_dqt(j_decompress_ptr cinfo) 512 /* Process a DQT marker */ 513 { 514 JLONG length; 515 int n, i, prec; 516 unsigned int tmp; 517 JQUANT_TBL *quant_ptr; 518 INPUT_VARS(cinfo); 519 520 INPUT_2BYTES(cinfo, length, return FALSE); 521 length -= 2; 522 523 while (length > 0) { 524 INPUT_BYTE(cinfo, n, return FALSE); 525 prec = n >> 4; 526 n &= 0x0F; 527 528 TRACEMS2(cinfo, 1, JTRC_DQT, n, prec); 529 530 if (n >= NUM_QUANT_TBLS) 531 ERREXIT1(cinfo, JERR_DQT_INDEX, n); 532 533 if (cinfo->quant_tbl_ptrs[n] == NULL) 534 cinfo->quant_tbl_ptrs[n] = jpeg_alloc_quant_table((j_common_ptr)cinfo); 535 quant_ptr = cinfo->quant_tbl_ptrs[n]; 536 537 for (i = 0; i < DCTSIZE2; i++) { 538 if (prec) 539 INPUT_2BYTES(cinfo, tmp, return FALSE); 540 else 541 INPUT_BYTE(cinfo, tmp, return FALSE); 542 /* We convert the zigzag-order table to natural array order. */ 543 quant_ptr->quantval[jpeg_natural_order[i]] = (UINT16)tmp; 544 } 545 546 if (cinfo->err->trace_level >= 2) { 547 for (i = 0; i < DCTSIZE2; i += 8) { 548 TRACEMS8(cinfo, 2, JTRC_QUANTVALS, 549 quant_ptr->quantval[i], quant_ptr->quantval[i + 1], 550 quant_ptr->quantval[i + 2], quant_ptr->quantval[i + 3], 551 quant_ptr->quantval[i + 4], quant_ptr->quantval[i + 5], 552 quant_ptr->quantval[i + 6], quant_ptr->quantval[i + 7]); 553 } 554 } 555 556 length -= DCTSIZE2 + 1; 557 if (prec) length -= DCTSIZE2; 558 } 559 560 if (length != 0) 561 ERREXIT(cinfo, JERR_BAD_LENGTH); 562 563 INPUT_SYNC(cinfo); 564 return TRUE; 565 } 566 567 568 LOCAL(boolean) 569 get_dri(j_decompress_ptr cinfo) 570 /* Process a DRI marker */ 571 { 572 JLONG length; 573 unsigned int tmp; 574 INPUT_VARS(cinfo); 575 576 INPUT_2BYTES(cinfo, length, return FALSE); 577 578 if (length != 4) 579 ERREXIT(cinfo, JERR_BAD_LENGTH); 580 581 INPUT_2BYTES(cinfo, tmp, return FALSE); 582 583 TRACEMS1(cinfo, 1, JTRC_DRI, tmp); 584 585 cinfo->restart_interval = tmp; 586 587 INPUT_SYNC(cinfo); 588 return TRUE; 589 } 590 591 592 /* 593 * Routines for processing APPn and COM markers. 594 * These are either saved in memory or discarded, per application request. 595 * APP0 and APP14 are specially checked to see if they are 596 * JFIF and Adobe markers, respectively. 597 */ 598 599 #define APP0_DATA_LEN 14 /* Length of interesting data in APP0 */ 600 #define APP14_DATA_LEN 12 /* Length of interesting data in APP14 */ 601 #define APPN_DATA_LEN 14 /* Must be the largest of the above!! */ 602 603 604 LOCAL(void) 605 examine_app0(j_decompress_ptr cinfo, JOCTET *data, unsigned int datalen, 606 JLONG remaining) 607 /* Examine first few bytes from an APP0. 608 * Take appropriate action if it is a JFIF marker. 609 * datalen is # of bytes at data[], remaining is length of rest of marker data. 610 */ 611 { 612 JLONG totallen = (JLONG)datalen + remaining; 613 614 if (datalen >= APP0_DATA_LEN && 615 data[0] == 0x4A && 616 data[1] == 0x46 && 617 data[2] == 0x49 && 618 data[3] == 0x46 && 619 data[4] == 0) { 620 /* Found JFIF APP0 marker: save info */ 621 cinfo->saw_JFIF_marker = TRUE; 622 cinfo->JFIF_major_version = data[5]; 623 cinfo->JFIF_minor_version = data[6]; 624 cinfo->density_unit = data[7]; 625 cinfo->X_density = (data[8] << 8) + data[9]; 626 cinfo->Y_density = (data[10] << 8) + data[11]; 627 /* Check version. 628 * Major version must be 1, anything else signals an incompatible change. 629 * (We used to treat this as an error, but now it's a nonfatal warning, 630 * because some bozo at Hijaak couldn't read the spec.) 631 * Minor version should be 0..2, but process anyway if newer. 632 */ 633 if (cinfo->JFIF_major_version != 1) 634 WARNMS2(cinfo, JWRN_JFIF_MAJOR, 635 cinfo->JFIF_major_version, cinfo->JFIF_minor_version); 636 /* Generate trace messages */ 637 TRACEMS5(cinfo, 1, JTRC_JFIF, 638 cinfo->JFIF_major_version, cinfo->JFIF_minor_version, 639 cinfo->X_density, cinfo->Y_density, cinfo->density_unit); 640 /* Validate thumbnail dimensions and issue appropriate messages */ 641 if (data[12] | data[13]) 642 TRACEMS2(cinfo, 1, JTRC_JFIF_THUMBNAIL, data[12], data[13]); 643 totallen -= APP0_DATA_LEN; 644 if (totallen != ((JLONG)data[12] * (JLONG)data[13] * (JLONG)3)) 645 TRACEMS1(cinfo, 1, JTRC_JFIF_BADTHUMBNAILSIZE, (int)totallen); 646 } else if (datalen >= 6 && 647 data[0] == 0x4A && 648 data[1] == 0x46 && 649 data[2] == 0x58 && 650 data[3] == 0x58 && 651 data[4] == 0) { 652 /* Found JFIF "JFXX" extension APP0 marker */ 653 /* The library doesn't actually do anything with these, 654 * but we try to produce a helpful trace message. 655 */ 656 switch (data[5]) { 657 case 0x10: 658 TRACEMS1(cinfo, 1, JTRC_THUMB_JPEG, (int)totallen); 659 break; 660 case 0x11: 661 TRACEMS1(cinfo, 1, JTRC_THUMB_PALETTE, (int)totallen); 662 break; 663 case 0x13: 664 TRACEMS1(cinfo, 1, JTRC_THUMB_RGB, (int)totallen); 665 break; 666 default: 667 TRACEMS2(cinfo, 1, JTRC_JFIF_EXTENSION, data[5], (int)totallen); 668 break; 669 } 670 } else { 671 /* Start of APP0 does not match "JFIF" or "JFXX", or too short */ 672 TRACEMS1(cinfo, 1, JTRC_APP0, (int)totallen); 673 } 674 } 675 676 677 LOCAL(void) 678 examine_app14(j_decompress_ptr cinfo, JOCTET *data, unsigned int datalen, 679 JLONG remaining) 680 /* Examine first few bytes from an APP14. 681 * Take appropriate action if it is an Adobe marker. 682 * datalen is # of bytes at data[], remaining is length of rest of marker data. 683 */ 684 { 685 unsigned int version, flags0, flags1, transform; 686 687 if (datalen >= APP14_DATA_LEN && 688 data[0] == 0x41 && 689 data[1] == 0x64 && 690 data[2] == 0x6F && 691 data[3] == 0x62 && 692 data[4] == 0x65) { 693 /* Found Adobe APP14 marker */ 694 version = (data[5] << 8) + data[6]; 695 flags0 = (data[7] << 8) + data[8]; 696 flags1 = (data[9] << 8) + data[10]; 697 transform = data[11]; 698 TRACEMS4(cinfo, 1, JTRC_ADOBE, version, flags0, flags1, transform); 699 cinfo->saw_Adobe_marker = TRUE; 700 cinfo->Adobe_transform = (UINT8)transform; 701 } else { 702 /* Start of APP14 does not match "Adobe", or too short */ 703 TRACEMS1(cinfo, 1, JTRC_APP14, (int)(datalen + remaining)); 704 } 705 } 706 707 708 METHODDEF(boolean) 709 get_interesting_appn(j_decompress_ptr cinfo) 710 /* Process an APP0 or APP14 marker without saving it */ 711 { 712 JLONG length; 713 JOCTET b[APPN_DATA_LEN]; 714 unsigned int i, numtoread; 715 INPUT_VARS(cinfo); 716 717 INPUT_2BYTES(cinfo, length, return FALSE); 718 length -= 2; 719 720 /* get the interesting part of the marker data */ 721 if (length >= APPN_DATA_LEN) 722 numtoread = APPN_DATA_LEN; 723 else if (length > 0) 724 numtoread = (unsigned int)length; 725 else 726 numtoread = 0; 727 for (i = 0; i < numtoread; i++) 728 INPUT_BYTE(cinfo, b[i], return FALSE); 729 length -= numtoread; 730 731 /* process it */ 732 switch (cinfo->unread_marker) { 733 case M_APP0: 734 examine_app0(cinfo, (JOCTET *)b, numtoread, length); 735 break; 736 case M_APP14: 737 examine_app14(cinfo, (JOCTET *)b, numtoread, length); 738 break; 739 default: 740 /* can't get here unless jpeg_save_markers chooses wrong processor */ 741 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker); 742 break; 743 } 744 745 /* skip any remaining data -- could be lots */ 746 INPUT_SYNC(cinfo); 747 if (length > 0) 748 (*cinfo->src->skip_input_data) (cinfo, (long)length); 749 750 return TRUE; 751 } 752 753 754 #ifdef SAVE_MARKERS_SUPPORTED 755 756 METHODDEF(boolean) 757 save_marker(j_decompress_ptr cinfo) 758 /* Save an APPn or COM marker into the marker list */ 759 { 760 my_marker_ptr marker = (my_marker_ptr)cinfo->marker; 761 jpeg_saved_marker_ptr cur_marker = marker->cur_marker; 762 unsigned int bytes_read, data_length; 763 JOCTET *data; 764 JLONG length = 0; 765 INPUT_VARS(cinfo); 766 767 if (cur_marker == NULL) { 768 /* begin reading a marker */ 769 INPUT_2BYTES(cinfo, length, return FALSE); 770 length -= 2; 771 if (length >= 0) { /* watch out for bogus length word */ 772 /* figure out how much we want to save */ 773 unsigned int limit; 774 if (cinfo->unread_marker == (int)M_COM) 775 limit = marker->length_limit_COM; 776 else 777 limit = marker->length_limit_APPn[cinfo->unread_marker - (int)M_APP0]; 778 if ((unsigned int)length < limit) 779 limit = (unsigned int)length; 780 /* allocate and initialize the marker item */ 781 cur_marker = (jpeg_saved_marker_ptr) 782 (*cinfo->mem->alloc_large) ((j_common_ptr)cinfo, JPOOL_IMAGE, 783 sizeof(struct jpeg_marker_struct) + limit); 784 cur_marker->next = NULL; 785 cur_marker->marker = (UINT8)cinfo->unread_marker; 786 cur_marker->original_length = (unsigned int)length; 787 cur_marker->data_length = limit; 788 /* data area is just beyond the jpeg_marker_struct */ 789 data = cur_marker->data = (JOCTET *)(cur_marker + 1); 790 marker->cur_marker = cur_marker; 791 marker->bytes_read = 0; 792 bytes_read = 0; 793 data_length = limit; 794 } else { 795 /* deal with bogus length word */ 796 bytes_read = data_length = 0; 797 data = NULL; 798 } 799 } else { 800 /* resume reading a marker */ 801 bytes_read = marker->bytes_read; 802 data_length = cur_marker->data_length; 803 data = cur_marker->data + bytes_read; 804 } 805 806 while (bytes_read < data_length) { 807 INPUT_SYNC(cinfo); /* move the restart point to here */ 808 marker->bytes_read = bytes_read; 809 /* If there's not at least one byte in buffer, suspend */ 810 MAKE_BYTE_AVAIL(cinfo, return FALSE); 811 /* Copy bytes with reasonable rapidity */ 812 while (bytes_read < data_length && bytes_in_buffer > 0) { 813 *data++ = *next_input_byte++; 814 bytes_in_buffer--; 815 bytes_read++; 816 } 817 } 818 819 /* Done reading what we want to read */ 820 if (cur_marker != NULL) { /* will be NULL if bogus length word */ 821 /* Add new marker to end of list */ 822 if (cinfo->marker_list == NULL || cinfo->master->marker_list_end == NULL) { 823 cinfo->marker_list = cinfo->master->marker_list_end = cur_marker; 824 } else { 825 cinfo->master->marker_list_end->next = cur_marker; 826 cinfo->master->marker_list_end = cur_marker; 827 } 828 /* Reset pointer & calc remaining data length */ 829 data = cur_marker->data; 830 length = cur_marker->original_length - data_length; 831 } 832 /* Reset to initial state for next marker */ 833 marker->cur_marker = NULL; 834 835 /* Process the marker if interesting; else just make a generic trace msg */ 836 switch (cinfo->unread_marker) { 837 case M_APP0: 838 examine_app0(cinfo, data, data_length, length); 839 break; 840 case M_APP14: 841 examine_app14(cinfo, data, data_length, length); 842 break; 843 default: 844 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, 845 (int)(data_length + length)); 846 break; 847 } 848 849 /* skip any remaining data -- could be lots */ 850 INPUT_SYNC(cinfo); /* do before skip_input_data */ 851 if (length > 0) 852 (*cinfo->src->skip_input_data) (cinfo, (long)length); 853 854 return TRUE; 855 } 856 857 #endif /* SAVE_MARKERS_SUPPORTED */ 858 859 860 METHODDEF(boolean) 861 skip_variable(j_decompress_ptr cinfo) 862 /* Skip over an unknown or uninteresting variable-length marker */ 863 { 864 JLONG length; 865 INPUT_VARS(cinfo); 866 867 INPUT_2BYTES(cinfo, length, return FALSE); 868 length -= 2; 869 870 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, (int)length); 871 872 INPUT_SYNC(cinfo); /* do before skip_input_data */ 873 if (length > 0) 874 (*cinfo->src->skip_input_data) (cinfo, (long)length); 875 876 return TRUE; 877 } 878 879 880 /* 881 * Find the next JPEG marker, save it in cinfo->unread_marker. 882 * Returns FALSE if had to suspend before reaching a marker; 883 * in that case cinfo->unread_marker is unchanged. 884 * 885 * Note that the result might not be a valid marker code, 886 * but it will never be 0 or FF. 887 */ 888 889 LOCAL(boolean) 890 next_marker(j_decompress_ptr cinfo) 891 { 892 int c; 893 INPUT_VARS(cinfo); 894 895 for (;;) { 896 INPUT_BYTE(cinfo, c, return FALSE); 897 /* Skip any non-FF bytes. 898 * This may look a bit inefficient, but it will not occur in a valid file. 899 * We sync after each discarded byte so that a suspending data source 900 * can discard the byte from its buffer. 901 */ 902 while (c != 0xFF) { 903 cinfo->marker->discarded_bytes++; 904 INPUT_SYNC(cinfo); 905 INPUT_BYTE(cinfo, c, return FALSE); 906 } 907 /* This loop swallows any duplicate FF bytes. Extra FFs are legal as 908 * pad bytes, so don't count them in discarded_bytes. We assume there 909 * will not be so many consecutive FF bytes as to overflow a suspending 910 * data source's input buffer. 911 */ 912 do { 913 INPUT_BYTE(cinfo, c, return FALSE); 914 } while (c == 0xFF); 915 if (c != 0) 916 break; /* found a valid marker, exit loop */ 917 /* Reach here if we found a stuffed-zero data sequence (FF/00). 918 * Discard it and loop back to try again. 919 */ 920 cinfo->marker->discarded_bytes += 2; 921 INPUT_SYNC(cinfo); 922 } 923 924 if (cinfo->marker->discarded_bytes != 0) { 925 WARNMS2(cinfo, JWRN_EXTRANEOUS_DATA, cinfo->marker->discarded_bytes, c); 926 cinfo->marker->discarded_bytes = 0; 927 } 928 929 cinfo->unread_marker = c; 930 931 INPUT_SYNC(cinfo); 932 return TRUE; 933 } 934 935 936 LOCAL(boolean) 937 first_marker(j_decompress_ptr cinfo) 938 /* Like next_marker, but used to obtain the initial SOI marker. */ 939 /* For this marker, we do not allow preceding garbage or fill; otherwise, 940 * we might well scan an entire input file before realizing it ain't JPEG. 941 * If an application wants to process non-JFIF files, it must seek to the 942 * SOI before calling the JPEG library. 943 */ 944 { 945 int c, c2; 946 INPUT_VARS(cinfo); 947 948 INPUT_BYTE(cinfo, c, return FALSE); 949 INPUT_BYTE(cinfo, c2, return FALSE); 950 if (c != 0xFF || c2 != (int)M_SOI) 951 ERREXIT2(cinfo, JERR_NO_SOI, c, c2); 952 953 cinfo->unread_marker = c2; 954 955 INPUT_SYNC(cinfo); 956 return TRUE; 957 } 958 959 960 /* 961 * Read markers until SOS or EOI. 962 * 963 * Returns same codes as are defined for jpeg_consume_input: 964 * JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI. 965 */ 966 967 METHODDEF(int) 968 read_markers(j_decompress_ptr cinfo) 969 { 970 /* Outer loop repeats once for each marker. */ 971 for (;;) { 972 /* Collect the marker proper, unless we already did. */ 973 /* NB: first_marker() enforces the requirement that SOI appear first. */ 974 if (cinfo->unread_marker == 0) { 975 if (!cinfo->marker->saw_SOI) { 976 if (!first_marker(cinfo)) 977 return JPEG_SUSPENDED; 978 } else { 979 if (!next_marker(cinfo)) 980 return JPEG_SUSPENDED; 981 } 982 } 983 /* At this point cinfo->unread_marker contains the marker code and the 984 * input point is just past the marker proper, but before any parameters. 985 * A suspension will cause us to return with this state still true. 986 */ 987 switch (cinfo->unread_marker) { 988 case M_SOI: 989 if (!get_soi(cinfo)) 990 return JPEG_SUSPENDED; 991 break; 992 993 case M_SOF0: /* Baseline */ 994 case M_SOF1: /* Extended sequential, Huffman */ 995 if (!get_sof(cinfo, FALSE, FALSE, FALSE)) 996 return JPEG_SUSPENDED; 997 break; 998 999 case M_SOF2: /* Progressive, Huffman */ 1000 if (!get_sof(cinfo, TRUE, FALSE, FALSE)) 1001 return JPEG_SUSPENDED; 1002 break; 1003 1004 case M_SOF3: /* Lossless, Huffman */ 1005 if (!get_sof(cinfo, FALSE, TRUE, FALSE)) 1006 return JPEG_SUSPENDED; 1007 break; 1008 1009 case M_SOF9: /* Extended sequential, arithmetic */ 1010 if (!get_sof(cinfo, FALSE, FALSE, TRUE)) 1011 return JPEG_SUSPENDED; 1012 break; 1013 1014 case M_SOF10: /* Progressive, arithmetic */ 1015 if (!get_sof(cinfo, TRUE, FALSE, TRUE)) 1016 return JPEG_SUSPENDED; 1017 break; 1018 1019 case M_SOF11: /* Lossless, arithmetic */ 1020 if (!get_sof(cinfo, FALSE, TRUE, TRUE)) 1021 return JPEG_SUSPENDED; 1022 break; 1023 1024 /* Currently unsupported SOFn types */ 1025 case M_SOF5: /* Differential sequential, Huffman */ 1026 case M_SOF6: /* Differential progressive, Huffman */ 1027 case M_SOF7: /* Differential lossless, Huffman */ 1028 case M_JPG: /* Reserved for JPEG extensions */ 1029 case M_SOF13: /* Differential sequential, arithmetic */ 1030 case M_SOF14: /* Differential progressive, arithmetic */ 1031 case M_SOF15: /* Differential lossless, arithmetic */ 1032 ERREXIT1(cinfo, JERR_SOF_UNSUPPORTED, cinfo->unread_marker); 1033 break; 1034 1035 case M_SOS: 1036 if (!get_sos(cinfo)) 1037 return JPEG_SUSPENDED; 1038 cinfo->unread_marker = 0; /* processed the marker */ 1039 return JPEG_REACHED_SOS; 1040 1041 case M_EOI: 1042 TRACEMS(cinfo, 1, JTRC_EOI); 1043 cinfo->unread_marker = 0; /* processed the marker */ 1044 return JPEG_REACHED_EOI; 1045 1046 case M_DAC: 1047 if (!get_dac(cinfo)) 1048 return JPEG_SUSPENDED; 1049 break; 1050 1051 case M_DHT: 1052 if (!get_dht(cinfo)) 1053 return JPEG_SUSPENDED; 1054 break; 1055 1056 case M_DQT: 1057 if (!get_dqt(cinfo)) 1058 return JPEG_SUSPENDED; 1059 break; 1060 1061 case M_DRI: 1062 if (!get_dri(cinfo)) 1063 return JPEG_SUSPENDED; 1064 break; 1065 1066 case M_APP0: 1067 case M_APP1: 1068 case M_APP2: 1069 case M_APP3: 1070 case M_APP4: 1071 case M_APP5: 1072 case M_APP6: 1073 case M_APP7: 1074 case M_APP8: 1075 case M_APP9: 1076 case M_APP10: 1077 case M_APP11: 1078 case M_APP12: 1079 case M_APP13: 1080 case M_APP14: 1081 case M_APP15: 1082 if (!(*((my_marker_ptr)cinfo->marker)->process_APPn[ 1083 cinfo->unread_marker - (int)M_APP0]) (cinfo)) 1084 return JPEG_SUSPENDED; 1085 break; 1086 1087 case M_COM: 1088 if (!(*((my_marker_ptr)cinfo->marker)->process_COM) (cinfo)) 1089 return JPEG_SUSPENDED; 1090 break; 1091 1092 case M_RST0: /* these are all parameterless */ 1093 case M_RST1: 1094 case M_RST2: 1095 case M_RST3: 1096 case M_RST4: 1097 case M_RST5: 1098 case M_RST6: 1099 case M_RST7: 1100 case M_TEM: 1101 TRACEMS1(cinfo, 1, JTRC_PARMLESS_MARKER, cinfo->unread_marker); 1102 break; 1103 1104 case M_DNL: /* Ignore DNL ... perhaps the wrong thing */ 1105 if (!skip_variable(cinfo)) 1106 return JPEG_SUSPENDED; 1107 break; 1108 1109 default: /* must be DHP, EXP, JPGn, or RESn */ 1110 /* For now, we treat the reserved markers as fatal errors since they are 1111 * likely to be used to signal incompatible JPEG Part 3 extensions. 1112 * Once the JPEG 3 version-number marker is well defined, this code 1113 * ought to change! 1114 */ 1115 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker); 1116 break; 1117 } 1118 /* Successfully processed marker, so reset state variable */ 1119 cinfo->unread_marker = 0; 1120 } /* end loop */ 1121 } 1122 1123 1124 /* 1125 * Read a restart marker, which is expected to appear next in the datastream; 1126 * if the marker is not there, take appropriate recovery action. 1127 * Returns FALSE if suspension is required. 1128 * 1129 * This is called by the entropy decoder after it has read an appropriate 1130 * number of MCUs. cinfo->unread_marker may be nonzero if the entropy decoder 1131 * has already read a marker from the data source. Under normal conditions 1132 * cinfo->unread_marker will be reset to 0 before returning; if not reset, 1133 * it holds a marker which the decoder will be unable to read past. 1134 */ 1135 1136 METHODDEF(boolean) 1137 read_restart_marker(j_decompress_ptr cinfo) 1138 { 1139 /* Obtain a marker unless we already did. */ 1140 /* Note that next_marker will complain if it skips any data. */ 1141 if (cinfo->unread_marker == 0) { 1142 if (!next_marker(cinfo)) 1143 return FALSE; 1144 } 1145 1146 if (cinfo->unread_marker == 1147 ((int)M_RST0 + cinfo->marker->next_restart_num)) { 1148 /* Normal case --- swallow the marker and let entropy decoder continue */ 1149 TRACEMS1(cinfo, 3, JTRC_RST, cinfo->marker->next_restart_num); 1150 cinfo->unread_marker = 0; 1151 } else { 1152 /* Uh-oh, the restart markers have been messed up. */ 1153 /* Let the data source manager determine how to resync. */ 1154 if (!(*cinfo->src->resync_to_restart) (cinfo, 1155 cinfo->marker->next_restart_num)) 1156 return FALSE; 1157 } 1158 1159 /* Update next-restart state */ 1160 cinfo->marker->next_restart_num = (cinfo->marker->next_restart_num + 1) & 7; 1161 1162 return TRUE; 1163 } 1164 1165 1166 /* 1167 * This is the default resync_to_restart method for data source managers 1168 * to use if they don't have any better approach. Some data source managers 1169 * may be able to back up, or may have additional knowledge about the data 1170 * which permits a more intelligent recovery strategy; such managers would 1171 * presumably supply their own resync method. 1172 * 1173 * read_restart_marker calls resync_to_restart if it finds a marker other than 1174 * the restart marker it was expecting. (This code is *not* used unless 1175 * a nonzero restart interval has been declared.) cinfo->unread_marker is 1176 * the marker code actually found (might be anything, except 0 or FF). 1177 * The desired restart marker number (0..7) is passed as a parameter. 1178 * This routine is supposed to apply whatever error recovery strategy seems 1179 * appropriate in order to position the input stream to the next data segment. 1180 * Note that cinfo->unread_marker is treated as a marker appearing before 1181 * the current data-source input point; usually it should be reset to zero 1182 * before returning. 1183 * Returns FALSE if suspension is required. 1184 * 1185 * This implementation is substantially constrained by wanting to treat the 1186 * input as a data stream; this means we can't back up. Therefore, we have 1187 * only the following actions to work with: 1188 * 1. Simply discard the marker and let the entropy decoder resume at next 1189 * byte of file. 1190 * 2. Read forward until we find another marker, discarding intervening 1191 * data. (In theory we could look ahead within the current bufferload, 1192 * without having to discard data if we don't find the desired marker. 1193 * This idea is not implemented here, in part because it makes behavior 1194 * dependent on buffer size and chance buffer-boundary positions.) 1195 * 3. Leave the marker unread (by failing to zero cinfo->unread_marker). 1196 * This will cause the entropy decoder to process an empty data segment, 1197 * inserting dummy zeroes, and then we will reprocess the marker. 1198 * 1199 * #2 is appropriate if we think the desired marker lies ahead, while #3 is 1200 * appropriate if the found marker is a future restart marker (indicating 1201 * that we have missed the desired restart marker, probably because it got 1202 * corrupted). 1203 * We apply #2 or #3 if the found marker is a restart marker no more than 1204 * two counts behind or ahead of the expected one. We also apply #2 if the 1205 * found marker is not a legal JPEG marker code (it's certainly bogus data). 1206 * If the found marker is a restart marker more than 2 counts away, we do #1 1207 * (too much risk that the marker is erroneous; with luck we will be able to 1208 * resync at some future point). 1209 * For any valid non-restart JPEG marker, we apply #3. This keeps us from 1210 * overrunning the end of a scan. An implementation limited to single-scan 1211 * files might find it better to apply #2 for markers other than EOI, since 1212 * any other marker would have to be bogus data in that case. 1213 */ 1214 1215 GLOBAL(boolean) 1216 jpeg_resync_to_restart(j_decompress_ptr cinfo, int desired) 1217 { 1218 int marker = cinfo->unread_marker; 1219 int action = 1; 1220 1221 /* Always put up a warning. */ 1222 WARNMS2(cinfo, JWRN_MUST_RESYNC, marker, desired); 1223 1224 /* Outer loop handles repeated decision after scanning forward. */ 1225 for (;;) { 1226 if (marker < (int)M_SOF0) 1227 action = 2; /* invalid marker */ 1228 else if (marker < (int)M_RST0 || marker > (int)M_RST7) 1229 action = 3; /* valid non-restart marker */ 1230 else { 1231 if (marker == ((int)M_RST0 + ((desired + 1) & 7)) || 1232 marker == ((int)M_RST0 + ((desired + 2) & 7))) 1233 action = 3; /* one of the next two expected restarts */ 1234 else if (marker == ((int)M_RST0 + ((desired - 1) & 7)) || 1235 marker == ((int)M_RST0 + ((desired - 2) & 7))) 1236 action = 2; /* a prior restart, so advance */ 1237 else 1238 action = 1; /* desired restart or too far away */ 1239 } 1240 TRACEMS2(cinfo, 4, JTRC_RECOVERY_ACTION, marker, action); 1241 switch (action) { 1242 case 1: 1243 /* Discard marker and let entropy decoder resume processing. */ 1244 cinfo->unread_marker = 0; 1245 return TRUE; 1246 case 2: 1247 /* Scan to the next marker, and repeat the decision loop. */ 1248 if (!next_marker(cinfo)) 1249 return FALSE; 1250 marker = cinfo->unread_marker; 1251 break; 1252 case 3: 1253 /* Return without advancing past this marker. */ 1254 /* Entropy decoder will be forced to process an empty segment. */ 1255 return TRUE; 1256 } 1257 } /* end loop */ 1258 } 1259 1260 1261 /* 1262 * Reset marker processing state to begin a fresh datastream. 1263 */ 1264 1265 METHODDEF(void) 1266 reset_marker_reader(j_decompress_ptr cinfo) 1267 { 1268 my_marker_ptr marker = (my_marker_ptr)cinfo->marker; 1269 1270 cinfo->comp_info = NULL; /* until allocated by get_sof */ 1271 cinfo->input_scan_number = 0; /* no SOS seen yet */ 1272 cinfo->unread_marker = 0; /* no pending marker */ 1273 marker->pub.saw_SOI = FALSE; /* set internal state too */ 1274 marker->pub.saw_SOF = FALSE; 1275 marker->pub.discarded_bytes = 0; 1276 marker->cur_marker = NULL; 1277 } 1278 1279 1280 /* 1281 * Initialize the marker reader module. 1282 * This is called only once, when the decompression object is created. 1283 */ 1284 1285 GLOBAL(void) 1286 jinit_marker_reader(j_decompress_ptr cinfo) 1287 { 1288 my_marker_ptr marker; 1289 int i; 1290 1291 /* Create subobject in permanent pool */ 1292 marker = (my_marker_ptr) 1293 (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_PERMANENT, 1294 sizeof(my_marker_reader)); 1295 cinfo->marker = (struct jpeg_marker_reader *)marker; 1296 /* Initialize public method pointers */ 1297 marker->pub.reset_marker_reader = reset_marker_reader; 1298 marker->pub.read_markers = read_markers; 1299 marker->pub.read_restart_marker = read_restart_marker; 1300 /* Initialize COM/APPn processing. 1301 * By default, we examine and then discard APP0 and APP14, 1302 * but simply discard COM and all other APPn. 1303 */ 1304 marker->process_COM = skip_variable; 1305 marker->length_limit_COM = 0; 1306 for (i = 0; i < 16; i++) { 1307 marker->process_APPn[i] = skip_variable; 1308 marker->length_limit_APPn[i] = 0; 1309 } 1310 marker->process_APPn[0] = get_interesting_appn; 1311 marker->process_APPn[14] = get_interesting_appn; 1312 /* Reset marker processing state */ 1313 reset_marker_reader(cinfo); 1314 } 1315 1316 1317 /* 1318 * Control saving of COM and APPn markers into marker_list. 1319 */ 1320 1321 #ifdef SAVE_MARKERS_SUPPORTED 1322 1323 GLOBAL(void) 1324 jpeg_save_markers(j_decompress_ptr cinfo, int marker_code, 1325 unsigned int length_limit) 1326 { 1327 my_marker_ptr marker = (my_marker_ptr)cinfo->marker; 1328 long maxlength; 1329 jpeg_marker_parser_method processor; 1330 1331 /* Length limit mustn't be larger than what we can allocate 1332 * (should only be a concern in a 16-bit environment). 1333 */ 1334 maxlength = cinfo->mem->max_alloc_chunk - sizeof(struct jpeg_marker_struct); 1335 if (((long)length_limit) > maxlength) 1336 length_limit = (unsigned int)maxlength; 1337 1338 /* Choose processor routine to use. 1339 * APP0/APP14 have special requirements. 1340 */ 1341 if (length_limit) { 1342 processor = save_marker; 1343 /* If saving APP0/APP14, save at least enough for our internal use. */ 1344 if (marker_code == (int)M_APP0 && length_limit < APP0_DATA_LEN) 1345 length_limit = APP0_DATA_LEN; 1346 else if (marker_code == (int)M_APP14 && length_limit < APP14_DATA_LEN) 1347 length_limit = APP14_DATA_LEN; 1348 } else { 1349 processor = skip_variable; 1350 /* If discarding APP0/APP14, use our regular on-the-fly processor. */ 1351 if (marker_code == (int)M_APP0 || marker_code == (int)M_APP14) 1352 processor = get_interesting_appn; 1353 } 1354 1355 if (marker_code == (int)M_COM) { 1356 marker->process_COM = processor; 1357 marker->length_limit_COM = length_limit; 1358 } else if (marker_code >= (int)M_APP0 && marker_code <= (int)M_APP15) { 1359 marker->process_APPn[marker_code - (int)M_APP0] = processor; 1360 marker->length_limit_APPn[marker_code - (int)M_APP0] = length_limit; 1361 } else 1362 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code); 1363 } 1364 1365 #endif /* SAVE_MARKERS_SUPPORTED */ 1366 1367 1368 /* 1369 * Install a special processing method for COM or APPn markers. 1370 */ 1371 1372 GLOBAL(void) 1373 jpeg_set_marker_processor(j_decompress_ptr cinfo, int marker_code, 1374 jpeg_marker_parser_method routine) 1375 { 1376 my_marker_ptr marker = (my_marker_ptr)cinfo->marker; 1377 1378 if (marker_code == (int)M_COM) 1379 marker->process_COM = routine; 1380 else if (marker_code >= (int)M_APP0 && marker_code <= (int)M_APP15) 1381 marker->process_APPn[marker_code - (int)M_APP0] = routine; 1382 else 1383 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code); 1384 }