1 /* 2 * jdmarker.c 3 * 4 * Copyright (C) 1991-1998, Thomas G. Lane. 5 * Modified 2009-2019 by Guido Vollbeding. 6 * This file is part of the Independent JPEG Group's software. 7 * For conditions of distribution and use, see the accompanying README file. 8 * 9 * This file contains routines to decode JPEG datastream markers. 10 * Most of the complexity arises from our desire to support input 11 * suspension: if not all of the data for a marker is available, 12 * we must exit back to the application. On resumption, we reprocess 13 * the marker. 14 */ 15 16 #define JPEG_INTERNALS 17 #include "jinclude.h" 18 #include "jpeglib.h" 19 20 21 typedef enum { /* JPEG marker codes */ 22 M_SOF0 = 0xc0, 23 M_SOF1 = 0xc1, 24 M_SOF2 = 0xc2, 25 M_SOF3 = 0xc3, 26 27 M_SOF5 = 0xc5, 28 M_SOF6 = 0xc6, 29 M_SOF7 = 0xc7, 30 31 M_JPG = 0xc8, 32 M_SOF9 = 0xc9, 33 M_SOF10 = 0xca, 34 M_SOF11 = 0xcb, 35 36 M_SOF13 = 0xcd, 37 M_SOF14 = 0xce, 38 M_SOF15 = 0xcf, 39 40 M_DHT = 0xc4, 41 42 M_DAC = 0xcc, 43 44 M_RST0 = 0xd0, 45 M_RST1 = 0xd1, 46 M_RST2 = 0xd2, 47 M_RST3 = 0xd3, 48 M_RST4 = 0xd4, 49 M_RST5 = 0xd5, 50 M_RST6 = 0xd6, 51 M_RST7 = 0xd7, 52 53 M_SOI = 0xd8, 54 M_EOI = 0xd9, 55 M_SOS = 0xda, 56 M_DQT = 0xdb, 57 M_DNL = 0xdc, 58 M_DRI = 0xdd, 59 M_DHP = 0xde, 60 M_EXP = 0xdf, 61 62 M_APP0 = 0xe0, 63 M_APP1 = 0xe1, 64 M_APP2 = 0xe2, 65 M_APP3 = 0xe3, 66 M_APP4 = 0xe4, 67 M_APP5 = 0xe5, 68 M_APP6 = 0xe6, 69 M_APP7 = 0xe7, 70 M_APP8 = 0xe8, 71 M_APP9 = 0xe9, 72 M_APP10 = 0xea, 73 M_APP11 = 0xeb, 74 M_APP12 = 0xec, 75 M_APP13 = 0xed, 76 M_APP14 = 0xee, 77 M_APP15 = 0xef, 78 79 M_JPG0 = 0xf0, 80 M_JPG8 = 0xf8, 81 M_JPG13 = 0xfd, 82 M_COM = 0xfe, 83 84 M_TEM = 0x01, 85 86 M_ERROR = 0x100 87 } JPEG_MARKER; 88 89 90 /* Private state */ 91 92 typedef struct { 93 struct jpeg_marker_reader pub; /* public fields */ 94 95 /* Application-overridable marker processing methods */ 96 jpeg_marker_parser_method process_COM; 97 jpeg_marker_parser_method process_APPn[16]; 98 99 /* Limit on marker data length to save for each marker type */ 100 unsigned int length_limit_COM; 101 unsigned int length_limit_APPn[16]; 102 103 /* Status of COM/APPn marker saving */ 104 jpeg_saved_marker_ptr cur_marker; /* NULL if not processing a marker */ 105 unsigned int bytes_read; /* data bytes read so far in marker */ 106 /* Note: cur_marker is not linked into marker_list until it's all read. */ 107 } my_marker_reader; 108 109 typedef my_marker_reader * my_marker_ptr; 110 111 112 /* 113 * Macros for fetching data from the data source module. 114 * 115 * At all times, cinfo->src->next_input_byte and ->bytes_in_buffer reflect 116 * the current restart point; we update them only when we have reached a 117 * suitable place to restart if a suspension occurs. 118 */ 119 120 /* Declare and initialize local copies of input pointer/count */ 121 #define INPUT_VARS(cinfo) \ 122 struct jpeg_source_mgr * datasrc = (cinfo)->src; \ 123 const JOCTET * next_input_byte = datasrc->next_input_byte; \ 124 size_t bytes_in_buffer = datasrc->bytes_in_buffer 125 126 /* Unload the local copies --- do this only at a restart boundary */ 127 #define INPUT_SYNC(cinfo) \ 128 ( datasrc->next_input_byte = next_input_byte, \ 129 datasrc->bytes_in_buffer = bytes_in_buffer ) 130 131 /* Reload the local copies --- used only in MAKE_BYTE_AVAIL */ 132 #define INPUT_RELOAD(cinfo) \ 133 ( next_input_byte = datasrc->next_input_byte, \ 134 bytes_in_buffer = datasrc->bytes_in_buffer ) 135 136 /* Internal macro for INPUT_BYTE and INPUT_2BYTES: make a byte available. 137 * Note we do *not* do INPUT_SYNC before calling fill_input_buffer, 138 * but we must reload the local copies after a successful fill. 139 */ 140 #define MAKE_BYTE_AVAIL(cinfo,action) \ 141 if (bytes_in_buffer == 0) { \ 142 if (! (*datasrc->fill_input_buffer) (cinfo)) \ 143 { action; } \ 144 INPUT_RELOAD(cinfo); \ 145 } 146 147 /* Read a byte into variable V. 148 * If must suspend, take the specified action (typically "return FALSE"). 149 */ 150 #define INPUT_BYTE(cinfo,V,action) \ 151 MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \ 152 bytes_in_buffer--; \ 153 V = GETJOCTET(*next_input_byte++); ) 154 155 /* As above, but read two bytes interpreted as an unsigned 16-bit integer. 156 * V should be declared unsigned int or perhaps INT32. 157 */ 158 #define INPUT_2BYTES(cinfo,V,action) \ 159 MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \ 160 bytes_in_buffer--; \ 161 V = ((unsigned int) GETJOCTET(*next_input_byte++)) << 8; \ 162 MAKE_BYTE_AVAIL(cinfo,action); \ 163 bytes_in_buffer--; \ 164 V += GETJOCTET(*next_input_byte++); ) 165 166 167 /* 168 * Routines to process JPEG markers. 169 * 170 * Entry condition: JPEG marker itself has been read and its code saved 171 * in cinfo->unread_marker; input restart point is just after the marker. 172 * 173 * Exit: if return TRUE, have read and processed any parameters, and have 174 * updated the restart point to point after the parameters. 175 * If return FALSE, was forced to suspend before reaching end of 176 * marker parameters; restart point has not been moved. Same routine 177 * will be called again after application supplies more input data. 178 * 179 * This approach to suspension assumes that all of a marker's parameters 180 * can fit into a single input bufferload. This should hold for "normal" 181 * markers. Some COM/APPn markers might have large parameter segments 182 * that might not fit. If we are simply dropping such a marker, we use 183 * skip_input_data to get past it, and thereby put the problem on the 184 * source manager's shoulders. If we are saving the marker's contents 185 * into memory, we use a slightly different convention: when forced to 186 * suspend, the marker processor updates the restart point to the end of 187 * what it's consumed (ie, the end of the buffer) before returning FALSE. 188 * On resumption, cinfo->unread_marker still contains the marker code, 189 * but the data source will point to the next chunk of marker data. 190 * The marker processor must retain internal state to deal with this. 191 * 192 * Note that we don't bother to avoid duplicate trace messages if a 193 * suspension occurs within marker parameters. Other side effects 194 * require more care. 195 */ 196 197 198 LOCAL(boolean) 199 get_soi (j_decompress_ptr cinfo) 200 /* Process an SOI marker */ 201 { 202 int i; 203 204 TRACEMS(cinfo, 1, JTRC_SOI); 205 206 if (cinfo->marker->saw_SOI) 207 ERREXIT(cinfo, JERR_SOI_DUPLICATE); 208 209 /* Reset all parameters that are defined to be reset by SOI */ 210 211 for (i = 0; i < NUM_ARITH_TBLS; i++) { 212 cinfo->arith_dc_L[i] = 0; 213 cinfo->arith_dc_U[i] = 1; 214 cinfo->arith_ac_K[i] = 5; 215 } 216 cinfo->restart_interval = 0; 217 218 /* Set initial assumptions for colorspace etc */ 219 220 cinfo->jpeg_color_space = JCS_UNKNOWN; 221 cinfo->color_transform = JCT_NONE; 222 cinfo->CCIR601_sampling = FALSE; /* Assume non-CCIR sampling??? */ 223 224 cinfo->saw_JFIF_marker = FALSE; 225 cinfo->JFIF_major_version = 1; /* set default JFIF APP0 values */ 226 cinfo->JFIF_minor_version = 1; 227 cinfo->density_unit = 0; 228 cinfo->X_density = 1; 229 cinfo->Y_density = 1; 230 cinfo->saw_Adobe_marker = FALSE; 231 cinfo->Adobe_transform = 0; 232 233 cinfo->marker->saw_SOI = TRUE; 234 235 return TRUE; 236 } 237 238 239 LOCAL(boolean) 240 get_sof (j_decompress_ptr cinfo, boolean is_baseline, boolean is_prog, 241 boolean is_arith) 242 /* Process a SOFn marker */ 243 { 244 INT32 length; 245 int c, ci, i; 246 jpeg_component_info * compptr; 247 INPUT_VARS(cinfo); 248 249 cinfo->is_baseline = is_baseline; 250 cinfo->progressive_mode = is_prog; 251 cinfo->arith_code = is_arith; 252 253 INPUT_2BYTES(cinfo, length, return FALSE); 254 255 INPUT_BYTE(cinfo, cinfo->data_precision, return FALSE); 256 INPUT_2BYTES(cinfo, cinfo->image_height, return FALSE); 257 INPUT_2BYTES(cinfo, cinfo->image_width, return FALSE); 258 INPUT_BYTE(cinfo, cinfo->num_components, return FALSE); 259 260 length -= 8; 261 262 TRACEMS4(cinfo, 1, JTRC_SOF, cinfo->unread_marker, 263 (int) cinfo->image_width, (int) cinfo->image_height, 264 cinfo->num_components); 265 266 if (cinfo->marker->saw_SOF) 267 ERREXIT(cinfo, JERR_SOF_DUPLICATE); 268 269 /* We don't support files in which the image height is initially specified */ 270 /* as 0 and is later redefined by DNL. As long as we have to check that, */ 271 /* might as well have a general sanity check. */ 272 if (cinfo->image_height <= 0 || cinfo->image_width <= 0 || 273 cinfo->num_components <= 0) 274 ERREXIT(cinfo, JERR_EMPTY_IMAGE); 275 276 if (length != (cinfo->num_components * 3)) 277 ERREXIT(cinfo, JERR_BAD_LENGTH); 278 279 if (cinfo->comp_info == NULL) /* do only once, even if suspend */ 280 cinfo->comp_info = (jpeg_component_info *) (*cinfo->mem->alloc_small) 281 ((j_common_ptr) cinfo, JPOOL_IMAGE, 282 cinfo->num_components * SIZEOF(jpeg_component_info)); 283 284 for (ci = 0; ci < cinfo->num_components; ci++) { 285 INPUT_BYTE(cinfo, c, return FALSE); 286 /* Check to see whether component id has already been seen */ 287 /* (in violation of the spec, but unfortunately seen in some */ 288 /* files). If so, create "fake" component id equal to the */ 289 /* max id seen so far + 1. */ 290 for (i = 0, compptr = cinfo->comp_info; i < ci; i++, compptr++) { 291 if (c == compptr->component_id) { 292 compptr = cinfo->comp_info; 293 c = compptr->component_id; 294 compptr++; 295 for (i = 1; i < ci; i++, compptr++) { 296 if (compptr->component_id > c) c = compptr->component_id; 297 } 298 c++; 299 break; 300 } 301 } 302 compptr->component_id = c; 303 compptr->component_index = ci; 304 INPUT_BYTE(cinfo, c, return FALSE); 305 compptr->h_samp_factor = (c >> 4) & 15; 306 compptr->v_samp_factor = (c ) & 15; 307 INPUT_BYTE(cinfo, compptr->quant_tbl_no, return FALSE); 308 309 TRACEMS4(cinfo, 1, JTRC_SOF_COMPONENT, 310 compptr->component_id, compptr->h_samp_factor, 311 compptr->v_samp_factor, compptr->quant_tbl_no); 312 } 313 314 cinfo->marker->saw_SOF = TRUE; 315 316 INPUT_SYNC(cinfo); 317 return TRUE; 318 } 319 320 321 LOCAL(boolean) 322 get_sos (j_decompress_ptr cinfo) 323 /* Process a SOS marker */ 324 { 325 INT32 length; 326 int c, ci, i, n; 327 jpeg_component_info * compptr; 328 INPUT_VARS(cinfo); 329 330 if (! cinfo->marker->saw_SOF) 331 ERREXITS(cinfo, JERR_SOF_BEFORE, "SOS"); 332 333 INPUT_2BYTES(cinfo, length, return FALSE); 334 335 INPUT_BYTE(cinfo, n, return FALSE); /* Number of components */ 336 337 TRACEMS1(cinfo, 1, JTRC_SOS, n); 338 339 if (length != (n * 2 + 6) || n > MAX_COMPS_IN_SCAN || 340 (n == 0 && !cinfo->progressive_mode)) 341 /* pseudo SOS marker only allowed in progressive mode */ 342 ERREXIT(cinfo, JERR_BAD_LENGTH); 343 344 cinfo->comps_in_scan = n; 345 346 /* Collect the component-spec parameters */ 347 348 for (i = 0; i < n; i++) { 349 INPUT_BYTE(cinfo, c, return FALSE); 350 351 /* Detect the case where component id's are not unique, and, if so, */ 352 /* create a fake component id using the same logic as in get_sof. */ 353 /* Note: This also ensures that all of the SOF components are */ 354 /* referenced in the single scan case, which prevents access to */ 355 /* uninitialized memory in later decoding stages. */ 356 for (ci = 0; ci < i; ci++) { 357 if (c == cinfo->cur_comp_info[ci]->component_id) { 358 c = cinfo->cur_comp_info[0]->component_id; 359 for (ci = 1; ci < i; ci++) { 360 compptr = cinfo->cur_comp_info[ci]; 361 if (compptr->component_id > c) c = compptr->component_id; 362 } 363 c++; 364 break; 365 } 366 } 367 368 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 369 ci++, compptr++) { 370 if (c == compptr->component_id) 371 goto id_found; 372 } 373 374 ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, c); 375 376 id_found: 377 378 cinfo->cur_comp_info[i] = compptr; 379 INPUT_BYTE(cinfo, c, return FALSE); 380 compptr->dc_tbl_no = (c >> 4) & 15; 381 compptr->ac_tbl_no = (c ) & 15; 382 383 TRACEMS3(cinfo, 1, JTRC_SOS_COMPONENT, compptr->component_id, 384 compptr->dc_tbl_no, compptr->ac_tbl_no); 385 } 386 387 /* Collect the additional scan parameters Ss, Se, Ah/Al. */ 388 INPUT_BYTE(cinfo, c, return FALSE); 389 cinfo->Ss = c; 390 INPUT_BYTE(cinfo, c, return FALSE); 391 cinfo->Se = c; 392 INPUT_BYTE(cinfo, c, return FALSE); 393 cinfo->Ah = (c >> 4) & 15; 394 cinfo->Al = (c ) & 15; 395 396 TRACEMS4(cinfo, 1, JTRC_SOS_PARAMS, cinfo->Ss, cinfo->Se, 397 cinfo->Ah, cinfo->Al); 398 399 /* Prepare to scan data & restart markers */ 400 cinfo->marker->next_restart_num = 0; 401 402 /* Count another (non-pseudo) SOS marker */ 403 if (n) cinfo->input_scan_number++; 404 405 INPUT_SYNC(cinfo); 406 return TRUE; 407 } 408 409 410 #ifdef D_ARITH_CODING_SUPPORTED 411 412 LOCAL(boolean) 413 get_dac (j_decompress_ptr cinfo) 414 /* Process a DAC marker */ 415 { 416 INT32 length; 417 int index, val; 418 INPUT_VARS(cinfo); 419 420 INPUT_2BYTES(cinfo, length, return FALSE); 421 length -= 2; 422 423 while (length > 0) { 424 INPUT_BYTE(cinfo, index, return FALSE); 425 INPUT_BYTE(cinfo, val, return FALSE); 426 427 length -= 2; 428 429 TRACEMS2(cinfo, 1, JTRC_DAC, index, val); 430 431 if (index < 0 || index >= (2*NUM_ARITH_TBLS)) 432 ERREXIT1(cinfo, JERR_DAC_INDEX, index); 433 434 if (index >= NUM_ARITH_TBLS) { /* define AC table */ 435 cinfo->arith_ac_K[index-NUM_ARITH_TBLS] = (UINT8) val; 436 } else { /* define DC table */ 437 cinfo->arith_dc_L[index] = (UINT8) (val & 0x0F); 438 cinfo->arith_dc_U[index] = (UINT8) (val >> 4); 439 if (cinfo->arith_dc_L[index] > cinfo->arith_dc_U[index]) 440 ERREXIT1(cinfo, JERR_DAC_VALUE, val); 441 } 442 } 443 444 if (length != 0) 445 ERREXIT(cinfo, JERR_BAD_LENGTH); 446 447 INPUT_SYNC(cinfo); 448 return TRUE; 449 } 450 451 #else /* ! D_ARITH_CODING_SUPPORTED */ 452 453 #define get_dac(cinfo) skip_variable(cinfo) 454 455 #endif /* D_ARITH_CODING_SUPPORTED */ 456 457 458 LOCAL(boolean) 459 get_dht (j_decompress_ptr cinfo) 460 /* Process a DHT marker */ 461 { 462 INT32 length; 463 UINT8 bits[17]; 464 UINT8 huffval[256]; 465 int i, index, count; 466 JHUFF_TBL **htblptr; 467 INPUT_VARS(cinfo); 468 469 INPUT_2BYTES(cinfo, length, return FALSE); 470 length -= 2; 471 472 while (length > 16) { 473 INPUT_BYTE(cinfo, index, return FALSE); 474 475 TRACEMS1(cinfo, 1, JTRC_DHT, index); 476 477 bits[0] = 0; 478 count = 0; 479 for (i = 1; i <= 16; i++) { 480 INPUT_BYTE(cinfo, bits[i], return FALSE); 481 count += bits[i]; 482 } 483 484 length -= 1 + 16; 485 486 TRACEMS8(cinfo, 2, JTRC_HUFFBITS, 487 bits[1], bits[2], bits[3], bits[4], 488 bits[5], bits[6], bits[7], bits[8]); 489 TRACEMS8(cinfo, 2, JTRC_HUFFBITS, 490 bits[9], bits[10], bits[11], bits[12], 491 bits[13], bits[14], bits[15], bits[16]); 492 493 /* Here we just do minimal validation of the counts to avoid walking 494 * off the end of our table space. jdhuff.c will check more carefully. 495 */ 496 if (count > 256 || ((INT32) count) > length) 497 ERREXIT(cinfo, JERR_BAD_HUFF_TABLE); 498 499 for (i = 0; i < count; i++) 500 INPUT_BYTE(cinfo, huffval[i], return FALSE); 501 502 length -= count; 503 504 if (index & 0x10) { /* AC table definition */ 505 index -= 0x10; 506 htblptr = &cinfo->ac_huff_tbl_ptrs[index]; 507 } else { /* DC table definition */ 508 htblptr = &cinfo->dc_huff_tbl_ptrs[index]; 509 } 510 511 if (index < 0 || index >= NUM_HUFF_TBLS) 512 ERREXIT1(cinfo, JERR_DHT_INDEX, index); 513 514 if (*htblptr == NULL) 515 *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo); 516 517 MEMCOPY((*htblptr)->bits, bits, SIZEOF((*htblptr)->bits)); 518 if (count > 0) 519 MEMCOPY((*htblptr)->huffval, huffval, count * SIZEOF(UINT8)); 520 } 521 522 if (length != 0) 523 ERREXIT(cinfo, JERR_BAD_LENGTH); 524 525 INPUT_SYNC(cinfo); 526 return TRUE; 527 } 528 529 530 LOCAL(boolean) 531 get_dqt (j_decompress_ptr cinfo) 532 /* Process a DQT marker */ 533 { 534 INT32 length, count, i; 535 int n, prec; 536 unsigned int tmp; 537 JQUANT_TBL *quant_ptr; 538 const int *natural_order; 539 INPUT_VARS(cinfo); 540 541 INPUT_2BYTES(cinfo, length, return FALSE); 542 length -= 2; 543 544 while (length > 0) { 545 length--; 546 INPUT_BYTE(cinfo, n, return FALSE); 547 prec = n >> 4; 548 n &= 0x0F; 549 550 TRACEMS2(cinfo, 1, JTRC_DQT, n, prec); 551 552 if (n >= NUM_QUANT_TBLS) 553 ERREXIT1(cinfo, JERR_DQT_INDEX, n); 554 555 if (cinfo->quant_tbl_ptrs[n] == NULL) 556 cinfo->quant_tbl_ptrs[n] = jpeg_alloc_quant_table((j_common_ptr) cinfo); 557 quant_ptr = cinfo->quant_tbl_ptrs[n]; 558 559 if (prec) { 560 if (length < DCTSIZE2 * 2) { 561 /* Initialize full table for safety. */ 562 for (i = 0; i < DCTSIZE2; i++) { 563 quant_ptr->quantval[i] = 1; 564 } 565 count = length >> 1; 566 } else 567 count = DCTSIZE2; 568 } else { 569 if (length < DCTSIZE2) { 570 /* Initialize full table for safety. */ 571 for (i = 0; i < DCTSIZE2; i++) { 572 quant_ptr->quantval[i] = 1; 573 } 574 count = length; 575 } else 576 count = DCTSIZE2; 577 } 578 579 switch ((int) count) { 580 case (2*2): natural_order = jpeg_natural_order2; break; 581 case (3*3): natural_order = jpeg_natural_order3; break; 582 case (4*4): natural_order = jpeg_natural_order4; break; 583 case (5*5): natural_order = jpeg_natural_order5; break; 584 case (6*6): natural_order = jpeg_natural_order6; break; 585 case (7*7): natural_order = jpeg_natural_order7; break; 586 default: natural_order = jpeg_natural_order; 587 } 588 589 for (i = 0; i < count; i++) { 590 if (prec) 591 INPUT_2BYTES(cinfo, tmp, return FALSE); 592 else 593 INPUT_BYTE(cinfo, tmp, return FALSE); 594 /* We convert the zigzag-order table to natural array order. */ 595 quant_ptr->quantval[natural_order[i]] = (UINT16) tmp; 596 } 597 598 if (cinfo->err->trace_level >= 2) { 599 for (i = 0; i < DCTSIZE2; i += 8) { 600 TRACEMS8(cinfo, 2, JTRC_QUANTVALS, 601 quant_ptr->quantval[i], quant_ptr->quantval[i+1], 602 quant_ptr->quantval[i+2], quant_ptr->quantval[i+3], 603 quant_ptr->quantval[i+4], quant_ptr->quantval[i+5], 604 quant_ptr->quantval[i+6], quant_ptr->quantval[i+7]); 605 } 606 } 607 608 length -= count; 609 if (prec) length -= count; 610 } 611 612 if (length != 0) 613 ERREXIT(cinfo, JERR_BAD_LENGTH); 614 615 INPUT_SYNC(cinfo); 616 return TRUE; 617 } 618 619 620 LOCAL(boolean) 621 get_dri (j_decompress_ptr cinfo) 622 /* Process a DRI marker */ 623 { 624 INT32 length; 625 unsigned int tmp; 626 INPUT_VARS(cinfo); 627 628 INPUT_2BYTES(cinfo, length, return FALSE); 629 630 if (length != 4) 631 ERREXIT(cinfo, JERR_BAD_LENGTH); 632 633 INPUT_2BYTES(cinfo, tmp, return FALSE); 634 635 TRACEMS1(cinfo, 1, JTRC_DRI, tmp); 636 637 cinfo->restart_interval = tmp; 638 639 INPUT_SYNC(cinfo); 640 return TRUE; 641 } 642 643 644 LOCAL(boolean) 645 get_lse (j_decompress_ptr cinfo) 646 /* Process an LSE marker */ 647 { 648 INT32 length; 649 unsigned int tmp; 650 int cid; 651 INPUT_VARS(cinfo); 652 653 if (! cinfo->marker->saw_SOF) 654 ERREXITS(cinfo, JERR_SOF_BEFORE, "LSE"); 655 656 if (cinfo->num_components < 3) goto bad; 657 658 INPUT_2BYTES(cinfo, length, return FALSE); 659 660 if (length != 24) 661 ERREXIT(cinfo, JERR_BAD_LENGTH); 662 663 INPUT_BYTE(cinfo, tmp, return FALSE); 664 if (tmp != 0x0D) /* ID inverse transform specification */ 665 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker); 666 INPUT_2BYTES(cinfo, tmp, return FALSE); 667 if (tmp != MAXJSAMPLE) goto bad; /* MAXTRANS */ 668 INPUT_BYTE(cinfo, tmp, return FALSE); 669 if (tmp != 3) goto bad; /* Nt=3 */ 670 INPUT_BYTE(cinfo, cid, return FALSE); 671 if (cid != cinfo->comp_info[1].component_id) goto bad; 672 INPUT_BYTE(cinfo, cid, return FALSE); 673 if (cid != cinfo->comp_info[0].component_id) goto bad; 674 INPUT_BYTE(cinfo, cid, return FALSE); 675 if (cid != cinfo->comp_info[2].component_id) goto bad; 676 INPUT_BYTE(cinfo, tmp, return FALSE); 677 if (tmp != 0x80) goto bad; /* F1: CENTER1=1, NORM1=0 */ 678 INPUT_2BYTES(cinfo, tmp, return FALSE); 679 if (tmp != 0) goto bad; /* A(1,1)=0 */ 680 INPUT_2BYTES(cinfo, tmp, return FALSE); 681 if (tmp != 0) goto bad; /* A(1,2)=0 */ 682 INPUT_BYTE(cinfo, tmp, return FALSE); 683 if (tmp != 0) goto bad; /* F2: CENTER2=0, NORM2=0 */ 684 INPUT_2BYTES(cinfo, tmp, return FALSE); 685 if (tmp != 1) goto bad; /* A(2,1)=1 */ 686 INPUT_2BYTES(cinfo, tmp, return FALSE); 687 if (tmp != 0) goto bad; /* A(2,2)=0 */ 688 INPUT_BYTE(cinfo, tmp, return FALSE); 689 if (tmp != 0) goto bad; /* F3: CENTER3=0, NORM3=0 */ 690 INPUT_2BYTES(cinfo, tmp, return FALSE); 691 if (tmp != 1) goto bad; /* A(3,1)=1 */ 692 INPUT_2BYTES(cinfo, tmp, return FALSE); 693 if (tmp != 0) { /* A(3,2)=0 */ 694 bad: 695 ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL); 696 } 697 698 /* OK, valid transform that we can handle. */ 699 cinfo->color_transform = JCT_SUBTRACT_GREEN; 700 701 INPUT_SYNC(cinfo); 702 return TRUE; 703 } 704 705 706 /* 707 * Routines for processing APPn and COM markers. 708 * These are either saved in memory or discarded, per application request. 709 * APP0 and APP14 are specially checked to see if they are 710 * JFIF and Adobe markers, respectively. 711 */ 712 713 #define APP0_DATA_LEN 14 /* Length of interesting data in APP0 */ 714 #define APP14_DATA_LEN 12 /* Length of interesting data in APP14 */ 715 #define APPN_DATA_LEN 14 /* Must be the largest of the above!! */ 716 717 718 LOCAL(void) 719 examine_app0 (j_decompress_ptr cinfo, JOCTET FAR * data, 720 unsigned int datalen, INT32 remaining) 721 /* Examine first few bytes from an APP0. 722 * Take appropriate action if it is a JFIF marker. 723 * datalen is # of bytes at data[], remaining is length of rest of marker data. 724 */ 725 { 726 INT32 totallen = (INT32) datalen + remaining; 727 728 if (datalen >= APP0_DATA_LEN && 729 GETJOCTET(data[0]) == 0x4A && 730 GETJOCTET(data[1]) == 0x46 && 731 GETJOCTET(data[2]) == 0x49 && 732 GETJOCTET(data[3]) == 0x46 && 733 GETJOCTET(data[4]) == 0) { 734 /* Found JFIF APP0 marker: save info */ 735 cinfo->saw_JFIF_marker = TRUE; 736 cinfo->JFIF_major_version = GETJOCTET(data[5]); 737 cinfo->JFIF_minor_version = GETJOCTET(data[6]); 738 cinfo->density_unit = GETJOCTET(data[7]); 739 cinfo->X_density = (GETJOCTET(data[8]) << 8) + GETJOCTET(data[9]); 740 cinfo->Y_density = (GETJOCTET(data[10]) << 8) + GETJOCTET(data[11]); 741 /* Check version. 742 * Major version must be 1 or 2, anything else signals an incompatible 743 * change. 744 * (We used to treat this as an error, but now it's a nonfatal warning, 745 * because some bozo at Hijaak couldn't read the spec.) 746 * Minor version should be 0..2, but process anyway if newer. 747 */ 748 if (cinfo->JFIF_major_version != 1 && cinfo->JFIF_major_version != 2) 749 WARNMS2(cinfo, JWRN_JFIF_MAJOR, 750 cinfo->JFIF_major_version, cinfo->JFIF_minor_version); 751 /* Generate trace messages */ 752 TRACEMS5(cinfo, 1, JTRC_JFIF, 753 cinfo->JFIF_major_version, cinfo->JFIF_minor_version, 754 cinfo->X_density, cinfo->Y_density, cinfo->density_unit); 755 /* Validate thumbnail dimensions and issue appropriate messages */ 756 if (GETJOCTET(data[12]) | GETJOCTET(data[13])) 757 TRACEMS2(cinfo, 1, JTRC_JFIF_THUMBNAIL, 758 GETJOCTET(data[12]), GETJOCTET(data[13])); 759 totallen -= APP0_DATA_LEN; 760 if (totallen != 761 ((INT32)GETJOCTET(data[12]) * (INT32)GETJOCTET(data[13]) * (INT32) 3)) 762 TRACEMS1(cinfo, 1, JTRC_JFIF_BADTHUMBNAILSIZE, (int) totallen); 763 } else if (datalen >= 6 && 764 GETJOCTET(data[0]) == 0x4A && 765 GETJOCTET(data[1]) == 0x46 && 766 GETJOCTET(data[2]) == 0x58 && 767 GETJOCTET(data[3]) == 0x58 && 768 GETJOCTET(data[4]) == 0) { 769 /* Found JFIF "JFXX" extension APP0 marker */ 770 /* The library doesn't actually do anything with these, 771 * but we try to produce a helpful trace message. 772 */ 773 switch (GETJOCTET(data[5])) { 774 case 0x10: 775 TRACEMS1(cinfo, 1, JTRC_THUMB_JPEG, (int) totallen); 776 break; 777 case 0x11: 778 TRACEMS1(cinfo, 1, JTRC_THUMB_PALETTE, (int) totallen); 779 break; 780 case 0x13: 781 TRACEMS1(cinfo, 1, JTRC_THUMB_RGB, (int) totallen); 782 break; 783 default: 784 TRACEMS2(cinfo, 1, JTRC_JFIF_EXTENSION, 785 GETJOCTET(data[5]), (int) totallen); 786 } 787 } else { 788 /* Start of APP0 does not match "JFIF" or "JFXX", or too short */ 789 TRACEMS1(cinfo, 1, JTRC_APP0, (int) totallen); 790 } 791 } 792 793 794 LOCAL(void) 795 examine_app14 (j_decompress_ptr cinfo, JOCTET FAR * data, 796 unsigned int datalen, INT32 remaining) 797 /* Examine first few bytes from an APP14. 798 * Take appropriate action if it is an Adobe marker. 799 * datalen is # of bytes at data[], remaining is length of rest of marker data. 800 */ 801 { 802 unsigned int version, flags0, flags1, transform; 803 804 if (datalen >= APP14_DATA_LEN && 805 GETJOCTET(data[0]) == 0x41 && 806 GETJOCTET(data[1]) == 0x64 && 807 GETJOCTET(data[2]) == 0x6F && 808 GETJOCTET(data[3]) == 0x62 && 809 GETJOCTET(data[4]) == 0x65) { 810 /* Found Adobe APP14 marker */ 811 version = (GETJOCTET(data[5]) << 8) + GETJOCTET(data[6]); 812 flags0 = (GETJOCTET(data[7]) << 8) + GETJOCTET(data[8]); 813 flags1 = (GETJOCTET(data[9]) << 8) + GETJOCTET(data[10]); 814 transform = GETJOCTET(data[11]); 815 TRACEMS4(cinfo, 1, JTRC_ADOBE, version, flags0, flags1, transform); 816 cinfo->saw_Adobe_marker = TRUE; 817 cinfo->Adobe_transform = (UINT8) transform; 818 } else { 819 /* Start of APP14 does not match "Adobe", or too short */ 820 TRACEMS1(cinfo, 1, JTRC_APP14, (int) (datalen + remaining)); 821 } 822 } 823 824 825 METHODDEF(boolean) 826 get_interesting_appn (j_decompress_ptr cinfo) 827 /* Process an APP0 or APP14 marker without saving it */ 828 { 829 INT32 length; 830 JOCTET b[APPN_DATA_LEN]; 831 unsigned int i, numtoread; 832 INPUT_VARS(cinfo); 833 834 INPUT_2BYTES(cinfo, length, return FALSE); 835 length -= 2; 836 837 /* get the interesting part of the marker data */ 838 if (length >= APPN_DATA_LEN) 839 numtoread = APPN_DATA_LEN; 840 else if (length > 0) 841 numtoread = (unsigned int) length; 842 else 843 numtoread = 0; 844 for (i = 0; i < numtoread; i++) 845 INPUT_BYTE(cinfo, b[i], return FALSE); 846 length -= numtoread; 847 848 /* process it */ 849 switch (cinfo->unread_marker) { 850 case M_APP0: 851 examine_app0(cinfo, (JOCTET FAR *) b, numtoread, length); 852 break; 853 case M_APP14: 854 examine_app14(cinfo, (JOCTET FAR *) b, numtoread, length); 855 break; 856 default: 857 /* can't get here unless jpeg_save_markers chooses wrong processor */ 858 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker); 859 } 860 861 /* skip any remaining data -- could be lots */ 862 INPUT_SYNC(cinfo); 863 if (length > 0) 864 (*cinfo->src->skip_input_data) (cinfo, (long) length); 865 866 return TRUE; 867 } 868 869 870 #ifdef SAVE_MARKERS_SUPPORTED 871 872 METHODDEF(boolean) 873 save_marker (j_decompress_ptr cinfo) 874 /* Save an APPn or COM marker into the marker list */ 875 { 876 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 877 jpeg_saved_marker_ptr cur_marker = marker->cur_marker; 878 unsigned int bytes_read, data_length; 879 JOCTET FAR * data; 880 INT32 length = 0; 881 INPUT_VARS(cinfo); 882 883 if (cur_marker == NULL) { 884 /* begin reading a marker */ 885 INPUT_2BYTES(cinfo, length, return FALSE); 886 length -= 2; 887 if (length >= 0) { /* watch out for bogus length word */ 888 /* figure out how much we want to save */ 889 unsigned int limit; 890 if (cinfo->unread_marker == (int) M_COM) 891 limit = marker->length_limit_COM; 892 else 893 limit = marker->length_limit_APPn[cinfo->unread_marker - (int) M_APP0]; 894 if ((unsigned int) length < limit) 895 limit = (unsigned int) length; 896 /* allocate and initialize the marker item */ 897 cur_marker = (jpeg_saved_marker_ptr) 898 (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE, 899 SIZEOF(struct jpeg_marker_struct) + limit); 900 cur_marker->next = NULL; 901 cur_marker->marker = (UINT8) cinfo->unread_marker; 902 cur_marker->original_length = (unsigned int) length; 903 cur_marker->data_length = limit; 904 /* data area is just beyond the jpeg_marker_struct */ 905 data = cur_marker->data = (JOCTET FAR *) (cur_marker + 1); 906 marker->cur_marker = cur_marker; 907 marker->bytes_read = 0; 908 bytes_read = 0; 909 data_length = limit; 910 } else { 911 /* deal with bogus length word */ 912 bytes_read = data_length = 0; 913 data = NULL; 914 } 915 } else { 916 /* resume reading a marker */ 917 bytes_read = marker->bytes_read; 918 data_length = cur_marker->data_length; 919 data = cur_marker->data + bytes_read; 920 } 921 922 while (bytes_read < data_length) { 923 INPUT_SYNC(cinfo); /* move the restart point to here */ 924 marker->bytes_read = bytes_read; 925 /* If there's not at least one byte in buffer, suspend */ 926 MAKE_BYTE_AVAIL(cinfo, return FALSE); 927 /* Copy bytes with reasonable rapidity */ 928 while (bytes_read < data_length && bytes_in_buffer > 0) { 929 *data++ = *next_input_byte++; 930 bytes_in_buffer--; 931 bytes_read++; 932 } 933 } 934 935 /* Done reading what we want to read */ 936 if (cur_marker != NULL) { /* will be NULL if bogus length word */ 937 /* Add new marker to end of list */ 938 if (cinfo->marker_list == NULL) { 939 cinfo->marker_list = cur_marker; 940 } else { 941 jpeg_saved_marker_ptr prev = cinfo->marker_list; 942 while (prev->next != NULL) 943 prev = prev->next; 944 prev->next = cur_marker; 945 } 946 /* Reset pointer & calc remaining data length */ 947 data = cur_marker->data; 948 length = cur_marker->original_length - data_length; 949 } 950 /* Reset to initial state for next marker */ 951 marker->cur_marker = NULL; 952 953 /* Process the marker if interesting; else just make a generic trace msg */ 954 switch (cinfo->unread_marker) { 955 case M_APP0: 956 examine_app0(cinfo, data, data_length, length); 957 break; 958 case M_APP14: 959 examine_app14(cinfo, data, data_length, length); 960 break; 961 default: 962 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, 963 (int) (data_length + length)); 964 } 965 966 /* skip any remaining data -- could be lots */ 967 INPUT_SYNC(cinfo); /* do before skip_input_data */ 968 if (length > 0) 969 (*cinfo->src->skip_input_data) (cinfo, (long) length); 970 971 return TRUE; 972 } 973 974 #endif /* SAVE_MARKERS_SUPPORTED */ 975 976 977 METHODDEF(boolean) 978 skip_variable (j_decompress_ptr cinfo) 979 /* Skip over an unknown or uninteresting variable-length marker */ 980 { 981 INT32 length; 982 INPUT_VARS(cinfo); 983 984 INPUT_2BYTES(cinfo, length, return FALSE); 985 length -= 2; 986 987 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, (int) length); 988 989 INPUT_SYNC(cinfo); /* do before skip_input_data */ 990 if (length > 0) 991 (*cinfo->src->skip_input_data) (cinfo, (long) length); 992 993 return TRUE; 994 } 995 996 997 /* 998 * Find the next JPEG marker, save it in cinfo->unread_marker. 999 * Returns FALSE if had to suspend before reaching a marker; 1000 * in that case cinfo->unread_marker is unchanged. 1001 * 1002 * Note that the result might not be a valid marker code, 1003 * but it will never be 0 or FF. 1004 */ 1005 1006 LOCAL(boolean) 1007 next_marker (j_decompress_ptr cinfo) 1008 { 1009 int c; 1010 INPUT_VARS(cinfo); 1011 1012 for (;;) { 1013 INPUT_BYTE(cinfo, c, return FALSE); 1014 /* Skip any non-FF bytes. 1015 * This may look a bit inefficient, but it will not occur in a valid file. 1016 * We sync after each discarded byte so that a suspending data source 1017 * can discard the byte from its buffer. 1018 */ 1019 while (c != 0xFF) { 1020 cinfo->marker->discarded_bytes++; 1021 INPUT_SYNC(cinfo); 1022 INPUT_BYTE(cinfo, c, return FALSE); 1023 } 1024 /* This loop swallows any duplicate FF bytes. Extra FFs are legal as 1025 * pad bytes, so don't count them in discarded_bytes. We assume there 1026 * will not be so many consecutive FF bytes as to overflow a suspending 1027 * data source's input buffer. 1028 */ 1029 do { 1030 INPUT_BYTE(cinfo, c, return FALSE); 1031 } while (c == 0xFF); 1032 if (c != 0) 1033 break; /* found a valid marker, exit loop */ 1034 /* Reach here if we found a stuffed-zero data sequence (FF/00). 1035 * Discard it and loop back to try again. 1036 */ 1037 cinfo->marker->discarded_bytes += 2; 1038 INPUT_SYNC(cinfo); 1039 } 1040 1041 if (cinfo->marker->discarded_bytes != 0) { 1042 WARNMS2(cinfo, JWRN_EXTRANEOUS_DATA, cinfo->marker->discarded_bytes, c); 1043 cinfo->marker->discarded_bytes = 0; 1044 } 1045 1046 cinfo->unread_marker = c; 1047 1048 INPUT_SYNC(cinfo); 1049 return TRUE; 1050 } 1051 1052 1053 LOCAL(boolean) 1054 first_marker (j_decompress_ptr cinfo) 1055 /* Like next_marker, but used to obtain the initial SOI marker. */ 1056 /* For this marker, we do not allow preceding garbage or fill; otherwise, 1057 * we might well scan an entire input file before realizing it ain't JPEG. 1058 * If an application wants to process non-JFIF files, it must seek to the 1059 * SOI before calling the JPEG library. 1060 */ 1061 { 1062 int c, c2; 1063 INPUT_VARS(cinfo); 1064 1065 INPUT_BYTE(cinfo, c, return FALSE); 1066 INPUT_BYTE(cinfo, c2, return FALSE); 1067 if (c != 0xFF || c2 != (int) M_SOI) 1068 ERREXIT2(cinfo, JERR_NO_SOI, c, c2); 1069 1070 cinfo->unread_marker = c2; 1071 1072 INPUT_SYNC(cinfo); 1073 return TRUE; 1074 } 1075 1076 1077 /* 1078 * Read markers until SOS or EOI. 1079 * 1080 * Returns same codes as are defined for jpeg_consume_input: 1081 * JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI. 1082 * 1083 * Note: This function may return a pseudo SOS marker (with zero 1084 * component number) for treat by input controller's consume_input. 1085 * consume_input itself should filter out (skip) the pseudo marker 1086 * after processing for the caller. 1087 */ 1088 1089 METHODDEF(int) 1090 read_markers (j_decompress_ptr cinfo) 1091 { 1092 /* Outer loop repeats once for each marker. */ 1093 for (;;) { 1094 /* Collect the marker proper, unless we already did. */ 1095 /* NB: first_marker() enforces the requirement that SOI appear first. */ 1096 if (cinfo->unread_marker == 0) { 1097 if (! cinfo->marker->saw_SOI) { 1098 if (! first_marker(cinfo)) 1099 return JPEG_SUSPENDED; 1100 } else { 1101 if (! next_marker(cinfo)) 1102 return JPEG_SUSPENDED; 1103 } 1104 } 1105 /* At this point cinfo->unread_marker contains the marker code and the 1106 * input point is just past the marker proper, but before any parameters. 1107 * A suspension will cause us to return with this state still true. 1108 */ 1109 switch (cinfo->unread_marker) { 1110 case M_SOI: 1111 if (! get_soi(cinfo)) 1112 return JPEG_SUSPENDED; 1113 break; 1114 1115 case M_SOF0: /* Baseline */ 1116 if (! get_sof(cinfo, TRUE, FALSE, FALSE)) 1117 return JPEG_SUSPENDED; 1118 break; 1119 1120 case M_SOF1: /* Extended sequential, Huffman */ 1121 if (! get_sof(cinfo, FALSE, FALSE, FALSE)) 1122 return JPEG_SUSPENDED; 1123 break; 1124 1125 case M_SOF2: /* Progressive, Huffman */ 1126 if (! get_sof(cinfo, FALSE, TRUE, FALSE)) 1127 return JPEG_SUSPENDED; 1128 break; 1129 1130 case M_SOF9: /* Extended sequential, arithmetic */ 1131 if (! get_sof(cinfo, FALSE, FALSE, TRUE)) 1132 return JPEG_SUSPENDED; 1133 break; 1134 1135 case M_SOF10: /* Progressive, arithmetic */ 1136 if (! get_sof(cinfo, FALSE, TRUE, TRUE)) 1137 return JPEG_SUSPENDED; 1138 break; 1139 1140 /* Currently unsupported SOFn types */ 1141 case M_SOF3: /* Lossless, Huffman */ 1142 case M_SOF5: /* Differential sequential, Huffman */ 1143 case M_SOF6: /* Differential progressive, Huffman */ 1144 case M_SOF7: /* Differential lossless, Huffman */ 1145 case M_JPG: /* Reserved for JPEG extensions */ 1146 case M_SOF11: /* Lossless, arithmetic */ 1147 case M_SOF13: /* Differential sequential, arithmetic */ 1148 case M_SOF14: /* Differential progressive, arithmetic */ 1149 case M_SOF15: /* Differential lossless, arithmetic */ 1150 ERREXIT1(cinfo, JERR_SOF_UNSUPPORTED, cinfo->unread_marker); 1151 break; 1152 1153 case M_SOS: 1154 if (! get_sos(cinfo)) 1155 return JPEG_SUSPENDED; 1156 cinfo->unread_marker = 0; /* processed the marker */ 1157 return JPEG_REACHED_SOS; 1158 1159 case M_EOI: 1160 TRACEMS(cinfo, 1, JTRC_EOI); 1161 cinfo->unread_marker = 0; /* processed the marker */ 1162 return JPEG_REACHED_EOI; 1163 1164 case M_DAC: 1165 if (! get_dac(cinfo)) 1166 return JPEG_SUSPENDED; 1167 break; 1168 1169 case M_DHT: 1170 if (! get_dht(cinfo)) 1171 return JPEG_SUSPENDED; 1172 break; 1173 1174 case M_DQT: 1175 if (! get_dqt(cinfo)) 1176 return JPEG_SUSPENDED; 1177 break; 1178 1179 case M_DRI: 1180 if (! get_dri(cinfo)) 1181 return JPEG_SUSPENDED; 1182 break; 1183 1184 case M_JPG8: 1185 if (! get_lse(cinfo)) 1186 return JPEG_SUSPENDED; 1187 break; 1188 1189 case M_APP0: 1190 case M_APP1: 1191 case M_APP2: 1192 case M_APP3: 1193 case M_APP4: 1194 case M_APP5: 1195 case M_APP6: 1196 case M_APP7: 1197 case M_APP8: 1198 case M_APP9: 1199 case M_APP10: 1200 case M_APP11: 1201 case M_APP12: 1202 case M_APP13: 1203 case M_APP14: 1204 case M_APP15: 1205 if (! (*((my_marker_ptr) cinfo->marker)->process_APPn[ 1206 cinfo->unread_marker - (int) M_APP0]) (cinfo)) 1207 return JPEG_SUSPENDED; 1208 break; 1209 1210 case M_COM: 1211 if (! (*((my_marker_ptr) cinfo->marker)->process_COM) (cinfo)) 1212 return JPEG_SUSPENDED; 1213 break; 1214 1215 case M_RST0: /* these are all parameterless */ 1216 case M_RST1: 1217 case M_RST2: 1218 case M_RST3: 1219 case M_RST4: 1220 case M_RST5: 1221 case M_RST6: 1222 case M_RST7: 1223 case M_TEM: 1224 TRACEMS1(cinfo, 1, JTRC_PARMLESS_MARKER, cinfo->unread_marker); 1225 break; 1226 1227 case M_DNL: /* Ignore DNL ... perhaps the wrong thing */ 1228 if (! skip_variable(cinfo)) 1229 return JPEG_SUSPENDED; 1230 break; 1231 1232 default: /* must be DHP, EXP, JPGn, or RESn */ 1233 /* For now, we treat the reserved markers as fatal errors since they are 1234 * likely to be used to signal incompatible JPEG Part 3 extensions. 1235 * Once the JPEG 3 version-number marker is well defined, this code 1236 * ought to change! 1237 */ 1238 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker); 1239 } 1240 /* Successfully processed marker, so reset state variable */ 1241 cinfo->unread_marker = 0; 1242 } /* end loop */ 1243 } 1244 1245 1246 /* 1247 * Read a restart marker, which is expected to appear next in the datastream; 1248 * if the marker is not there, take appropriate recovery action. 1249 * Returns FALSE if suspension is required. 1250 * 1251 * This is called by the entropy decoder after it has read an appropriate 1252 * number of MCUs. cinfo->unread_marker may be nonzero if the entropy decoder 1253 * has already read a marker from the data source. Under normal conditions 1254 * cinfo->unread_marker will be reset to 0 before returning; if not reset, 1255 * it holds a marker which the decoder will be unable to read past. 1256 */ 1257 1258 METHODDEF(boolean) 1259 read_restart_marker (j_decompress_ptr cinfo) 1260 { 1261 /* Obtain a marker unless we already did. */ 1262 /* Note that next_marker will complain if it skips any data. */ 1263 if (cinfo->unread_marker == 0) { 1264 if (! next_marker(cinfo)) 1265 return FALSE; 1266 } 1267 1268 if (cinfo->unread_marker == 1269 ((int) M_RST0 + cinfo->marker->next_restart_num)) { 1270 /* Normal case --- swallow the marker and let entropy decoder continue */ 1271 TRACEMS1(cinfo, 3, JTRC_RST, cinfo->marker->next_restart_num); 1272 cinfo->unread_marker = 0; 1273 } else { 1274 /* Uh-oh, the restart markers have been messed up. */ 1275 /* Let the data source manager determine how to resync. */ 1276 if (! (*cinfo->src->resync_to_restart) (cinfo, 1277 cinfo->marker->next_restart_num)) 1278 return FALSE; 1279 } 1280 1281 /* Update next-restart state */ 1282 cinfo->marker->next_restart_num = (cinfo->marker->next_restart_num + 1) & 7; 1283 1284 return TRUE; 1285 } 1286 1287 1288 /* 1289 * This is the default resync_to_restart method for data source managers 1290 * to use if they don't have any better approach. Some data source managers 1291 * may be able to back up, or may have additional knowledge about the data 1292 * which permits a more intelligent recovery strategy; such managers would 1293 * presumably supply their own resync method. 1294 * 1295 * read_restart_marker calls resync_to_restart if it finds a marker other than 1296 * the restart marker it was expecting. (This code is *not* used unless 1297 * a nonzero restart interval has been declared.) cinfo->unread_marker is 1298 * the marker code actually found (might be anything, except 0 or FF). 1299 * The desired restart marker number (0..7) is passed as a parameter. 1300 * This routine is supposed to apply whatever error recovery strategy seems 1301 * appropriate in order to position the input stream to the next data segment. 1302 * Note that cinfo->unread_marker is treated as a marker appearing before 1303 * the current data-source input point; usually it should be reset to zero 1304 * before returning. 1305 * Returns FALSE if suspension is required. 1306 * 1307 * This implementation is substantially constrained by wanting to treat the 1308 * input as a data stream; this means we can't back up. Therefore, we have 1309 * only the following actions to work with: 1310 * 1. Simply discard the marker and let the entropy decoder resume at next 1311 * byte of file. 1312 * 2. Read forward until we find another marker, discarding intervening 1313 * data. (In theory we could look ahead within the current bufferload, 1314 * without having to discard data if we don't find the desired marker. 1315 * This idea is not implemented here, in part because it makes behavior 1316 * dependent on buffer size and chance buffer-boundary positions.) 1317 * 3. Leave the marker unread (by failing to zero cinfo->unread_marker). 1318 * This will cause the entropy decoder to process an empty data segment, 1319 * inserting dummy zeroes, and then we will reprocess the marker. 1320 * 1321 * #2 is appropriate if we think the desired marker lies ahead, while #3 is 1322 * appropriate if the found marker is a future restart marker (indicating 1323 * that we have missed the desired restart marker, probably because it got 1324 * corrupted). 1325 * We apply #2 or #3 if the found marker is a restart marker no more than 1326 * two counts behind or ahead of the expected one. We also apply #2 if the 1327 * found marker is not a legal JPEG marker code (it's certainly bogus data). 1328 * If the found marker is a restart marker more than 2 counts away, we do #1 1329 * (too much risk that the marker is erroneous; with luck we will be able to 1330 * resync at some future point). 1331 * For any valid non-restart JPEG marker, we apply #3. This keeps us from 1332 * overrunning the end of a scan. An implementation limited to single-scan 1333 * files might find it better to apply #2 for markers other than EOI, since 1334 * any other marker would have to be bogus data in that case. 1335 */ 1336 1337 GLOBAL(boolean) 1338 jpeg_resync_to_restart (j_decompress_ptr cinfo, int desired) 1339 { 1340 int marker = cinfo->unread_marker; 1341 int action = 1; 1342 1343 /* Always put up a warning. */ 1344 WARNMS2(cinfo, JWRN_MUST_RESYNC, marker, desired); 1345 1346 /* Outer loop handles repeated decision after scanning forward. */ 1347 for (;;) { 1348 if (marker < (int) M_SOF0) 1349 action = 2; /* invalid marker */ 1350 else if (marker < (int) M_RST0 || marker > (int) M_RST7) 1351 action = 3; /* valid non-restart marker */ 1352 else { 1353 if (marker == ((int) M_RST0 + ((desired+1) & 7)) || 1354 marker == ((int) M_RST0 + ((desired+2) & 7))) 1355 action = 3; /* one of the next two expected restarts */ 1356 else if (marker == ((int) M_RST0 + ((desired-1) & 7)) || 1357 marker == ((int) M_RST0 + ((desired-2) & 7))) 1358 action = 2; /* a prior restart, so advance */ 1359 else 1360 action = 1; /* desired restart or too far away */ 1361 } 1362 TRACEMS2(cinfo, 4, JTRC_RECOVERY_ACTION, marker, action); 1363 switch (action) { 1364 case 1: 1365 /* Discard marker and let entropy decoder resume processing. */ 1366 cinfo->unread_marker = 0; 1367 return TRUE; 1368 case 2: 1369 /* Scan to the next marker, and repeat the decision loop. */ 1370 if (! next_marker(cinfo)) 1371 return FALSE; 1372 marker = cinfo->unread_marker; 1373 break; 1374 case 3: 1375 /* Return without advancing past this marker. */ 1376 /* Entropy decoder will be forced to process an empty segment. */ 1377 return TRUE; 1378 } 1379 } /* end loop */ 1380 } 1381 1382 1383 /* 1384 * Reset marker processing state to begin a fresh datastream. 1385 */ 1386 1387 METHODDEF(void) 1388 reset_marker_reader (j_decompress_ptr cinfo) 1389 { 1390 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 1391 1392 cinfo->comp_info = NULL; /* until allocated by get_sof */ 1393 cinfo->input_scan_number = 0; /* no SOS seen yet */ 1394 cinfo->unread_marker = 0; /* no pending marker */ 1395 marker->pub.saw_SOI = FALSE; /* set internal state too */ 1396 marker->pub.saw_SOF = FALSE; 1397 marker->pub.discarded_bytes = 0; 1398 marker->cur_marker = NULL; 1399 } 1400 1401 1402 /* 1403 * Initialize the marker reader module. 1404 * This is called only once, when the decompression object is created. 1405 */ 1406 1407 GLOBAL(void) 1408 jinit_marker_reader (j_decompress_ptr cinfo) 1409 { 1410 my_marker_ptr marker; 1411 int i; 1412 1413 /* Create subobject in permanent pool */ 1414 marker = (my_marker_ptr) (*cinfo->mem->alloc_small) 1415 ((j_common_ptr) cinfo, JPOOL_PERMANENT, SIZEOF(my_marker_reader)); 1416 cinfo->marker = &marker->pub; 1417 /* Initialize public method pointers */ 1418 marker->pub.reset_marker_reader = reset_marker_reader; 1419 marker->pub.read_markers = read_markers; 1420 marker->pub.read_restart_marker = read_restart_marker; 1421 /* Initialize COM/APPn processing. 1422 * By default, we examine and then discard APP0 and APP14, 1423 * but simply discard COM and all other APPn. 1424 */ 1425 marker->process_COM = skip_variable; 1426 marker->length_limit_COM = 0; 1427 for (i = 0; i < 16; i++) { 1428 marker->process_APPn[i] = skip_variable; 1429 marker->length_limit_APPn[i] = 0; 1430 } 1431 marker->process_APPn[0] = get_interesting_appn; 1432 marker->process_APPn[14] = get_interesting_appn; 1433 /* Reset marker processing state */ 1434 reset_marker_reader(cinfo); 1435 } 1436 1437 1438 /* 1439 * Control saving of COM and APPn markers into marker_list. 1440 */ 1441 1442 #ifdef SAVE_MARKERS_SUPPORTED 1443 1444 GLOBAL(void) 1445 jpeg_save_markers (j_decompress_ptr cinfo, int marker_code, 1446 unsigned int length_limit) 1447 { 1448 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 1449 long maxlength; 1450 jpeg_marker_parser_method processor; 1451 1452 /* Length limit mustn't be larger than what we can allocate 1453 * (should only be a concern in a 16-bit environment). 1454 */ 1455 maxlength = cinfo->mem->max_alloc_chunk - SIZEOF(struct jpeg_marker_struct); 1456 if (((long) length_limit) > maxlength) 1457 length_limit = (unsigned int) maxlength; 1458 1459 /* Choose processor routine to use. 1460 * APP0/APP14 have special requirements. 1461 */ 1462 if (length_limit) { 1463 processor = save_marker; 1464 /* If saving APP0/APP14, save at least enough for our internal use. */ 1465 if (marker_code == (int) M_APP0 && length_limit < APP0_DATA_LEN) 1466 length_limit = APP0_DATA_LEN; 1467 else if (marker_code == (int) M_APP14 && length_limit < APP14_DATA_LEN) 1468 length_limit = APP14_DATA_LEN; 1469 } else { 1470 processor = skip_variable; 1471 /* If discarding APP0/APP14, use our regular on-the-fly processor. */ 1472 if (marker_code == (int) M_APP0 || marker_code == (int) M_APP14) 1473 processor = get_interesting_appn; 1474 } 1475 1476 if (marker_code == (int) M_COM) { 1477 marker->process_COM = processor; 1478 marker->length_limit_COM = length_limit; 1479 } else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15) { 1480 marker->process_APPn[marker_code - (int) M_APP0] = processor; 1481 marker->length_limit_APPn[marker_code - (int) M_APP0] = length_limit; 1482 } else 1483 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code); 1484 } 1485 1486 #endif /* SAVE_MARKERS_SUPPORTED */ 1487 1488 1489 /* 1490 * Install a special processing method for COM or APPn markers. 1491 */ 1492 1493 GLOBAL(void) 1494 jpeg_set_marker_processor (j_decompress_ptr cinfo, int marker_code, 1495 jpeg_marker_parser_method routine) 1496 { 1497 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 1498 1499 if (marker_code == (int) M_COM) 1500 marker->process_COM = routine; 1501 else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15) 1502 marker->process_APPn[marker_code - (int) M_APP0] = routine; 1503 else 1504 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code); 1505 } 1506