1 /* 2 * jdmarker.c 3 * 4 * Copyright (C) 1991-1998, Thomas G. Lane. 5 * Modified 2009-2013 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 MEMZERO(huffval, SIZEOF(huffval)); /* pre-zero array for later copy */ 500 501 for (i = 0; i < count; i++) 502 INPUT_BYTE(cinfo, huffval[i], return FALSE); 503 504 length -= count; 505 506 if (index & 0x10) { /* AC table definition */ 507 index -= 0x10; 508 htblptr = &cinfo->ac_huff_tbl_ptrs[index]; 509 } else { /* DC table definition */ 510 htblptr = &cinfo->dc_huff_tbl_ptrs[index]; 511 } 512 513 if (index < 0 || index >= NUM_HUFF_TBLS) 514 ERREXIT1(cinfo, JERR_DHT_INDEX, index); 515 516 if (*htblptr == NULL) 517 *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo); 518 519 MEMCOPY((*htblptr)->bits, bits, SIZEOF((*htblptr)->bits)); 520 MEMCOPY((*htblptr)->huffval, huffval, SIZEOF((*htblptr)->huffval)); 521 } 522 523 if (length != 0) 524 ERREXIT(cinfo, JERR_BAD_LENGTH); 525 526 INPUT_SYNC(cinfo); 527 return TRUE; 528 } 529 530 531 LOCAL(boolean) 532 get_dqt (j_decompress_ptr cinfo) 533 /* Process a DQT marker */ 534 { 535 INT32 length, count, i; 536 int n, prec; 537 unsigned int tmp; 538 JQUANT_TBL *quant_ptr; 539 const int *natural_order; 540 INPUT_VARS(cinfo); 541 542 INPUT_2BYTES(cinfo, length, return FALSE); 543 length -= 2; 544 545 while (length > 0) { 546 length--; 547 INPUT_BYTE(cinfo, n, return FALSE); 548 prec = n >> 4; 549 n &= 0x0F; 550 551 TRACEMS2(cinfo, 1, JTRC_DQT, n, prec); 552 553 if (n >= NUM_QUANT_TBLS) 554 ERREXIT1(cinfo, JERR_DQT_INDEX, n); 555 556 if (cinfo->quant_tbl_ptrs[n] == NULL) 557 cinfo->quant_tbl_ptrs[n] = jpeg_alloc_quant_table((j_common_ptr) cinfo); 558 quant_ptr = cinfo->quant_tbl_ptrs[n]; 559 560 if (prec) { 561 if (length < DCTSIZE2 * 2) { 562 /* Initialize full table for safety. */ 563 for (i = 0; i < DCTSIZE2; i++) { 564 quant_ptr->quantval[i] = 1; 565 } 566 count = length >> 1; 567 } else 568 count = DCTSIZE2; 569 } else { 570 if (length < DCTSIZE2) { 571 /* Initialize full table for safety. */ 572 for (i = 0; i < DCTSIZE2; i++) { 573 quant_ptr->quantval[i] = 1; 574 } 575 count = length; 576 } else 577 count = DCTSIZE2; 578 } 579 580 switch (count) { 581 case (2*2): natural_order = jpeg_natural_order2; break; 582 case (3*3): natural_order = jpeg_natural_order3; break; 583 case (4*4): natural_order = jpeg_natural_order4; break; 584 case (5*5): natural_order = jpeg_natural_order5; break; 585 case (6*6): natural_order = jpeg_natural_order6; break; 586 case (7*7): natural_order = jpeg_natural_order7; break; 587 default: natural_order = jpeg_natural_order; break; 588 } 589 590 for (i = 0; i < count; i++) { 591 if (prec) 592 INPUT_2BYTES(cinfo, tmp, return FALSE); 593 else 594 INPUT_BYTE(cinfo, tmp, return FALSE); 595 /* We convert the zigzag-order table to natural array order. */ 596 quant_ptr->quantval[natural_order[i]] = (UINT16) tmp; 597 } 598 599 if (cinfo->err->trace_level >= 2) { 600 for (i = 0; i < DCTSIZE2; i += 8) { 601 TRACEMS8(cinfo, 2, JTRC_QUANTVALS, 602 quant_ptr->quantval[i], quant_ptr->quantval[i+1], 603 quant_ptr->quantval[i+2], quant_ptr->quantval[i+3], 604 quant_ptr->quantval[i+4], quant_ptr->quantval[i+5], 605 quant_ptr->quantval[i+6], quant_ptr->quantval[i+7]); 606 } 607 } 608 609 length -= count; 610 if (prec) length -= count; 611 } 612 613 if (length != 0) 614 ERREXIT(cinfo, JERR_BAD_LENGTH); 615 616 INPUT_SYNC(cinfo); 617 return TRUE; 618 } 619 620 621 LOCAL(boolean) 622 get_dri (j_decompress_ptr cinfo) 623 /* Process a DRI marker */ 624 { 625 INT32 length; 626 unsigned int tmp; 627 INPUT_VARS(cinfo); 628 629 INPUT_2BYTES(cinfo, length, return FALSE); 630 631 if (length != 4) 632 ERREXIT(cinfo, JERR_BAD_LENGTH); 633 634 INPUT_2BYTES(cinfo, tmp, return FALSE); 635 636 TRACEMS1(cinfo, 1, JTRC_DRI, tmp); 637 638 cinfo->restart_interval = tmp; 639 640 INPUT_SYNC(cinfo); 641 return TRUE; 642 } 643 644 645 LOCAL(boolean) 646 get_lse (j_decompress_ptr cinfo) 647 /* Process an LSE marker */ 648 { 649 INT32 length; 650 unsigned int tmp; 651 int cid; 652 INPUT_VARS(cinfo); 653 654 if (! cinfo->marker->saw_SOF) 655 ERREXITS(cinfo, JERR_SOF_BEFORE, "LSE"); 656 657 if (cinfo->num_components < 3) goto bad; 658 659 INPUT_2BYTES(cinfo, length, return FALSE); 660 661 if (length != 24) 662 ERREXIT(cinfo, JERR_BAD_LENGTH); 663 664 INPUT_BYTE(cinfo, tmp, return FALSE); 665 if (tmp != 0x0D) /* ID inverse transform specification */ 666 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker); 667 INPUT_2BYTES(cinfo, tmp, return FALSE); 668 if (tmp != MAXJSAMPLE) goto bad; /* MAXTRANS */ 669 INPUT_BYTE(cinfo, tmp, return FALSE); 670 if (tmp != 3) goto bad; /* Nt=3 */ 671 INPUT_BYTE(cinfo, cid, return FALSE); 672 if (cid != cinfo->comp_info[1].component_id) goto bad; 673 INPUT_BYTE(cinfo, cid, return FALSE); 674 if (cid != cinfo->comp_info[0].component_id) goto bad; 675 INPUT_BYTE(cinfo, cid, return FALSE); 676 if (cid != cinfo->comp_info[2].component_id) goto bad; 677 INPUT_BYTE(cinfo, tmp, return FALSE); 678 if (tmp != 0x80) goto bad; /* F1: CENTER1=1, NORM1=0 */ 679 INPUT_2BYTES(cinfo, tmp, return FALSE); 680 if (tmp != 0) goto bad; /* A(1,1)=0 */ 681 INPUT_2BYTES(cinfo, tmp, return FALSE); 682 if (tmp != 0) goto bad; /* A(1,2)=0 */ 683 INPUT_BYTE(cinfo, tmp, return FALSE); 684 if (tmp != 0) goto bad; /* F2: CENTER2=0, NORM2=0 */ 685 INPUT_2BYTES(cinfo, tmp, return FALSE); 686 if (tmp != 1) goto bad; /* A(2,1)=1 */ 687 INPUT_2BYTES(cinfo, tmp, return FALSE); 688 if (tmp != 0) goto bad; /* A(2,2)=0 */ 689 INPUT_BYTE(cinfo, tmp, return FALSE); 690 if (tmp != 0) goto bad; /* F3: CENTER3=0, NORM3=0 */ 691 INPUT_2BYTES(cinfo, tmp, return FALSE); 692 if (tmp != 1) goto bad; /* A(3,1)=1 */ 693 INPUT_2BYTES(cinfo, tmp, return FALSE); 694 if (tmp != 0) { /* A(3,2)=0 */ 695 bad: 696 ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL); 697 } 698 699 /* OK, valid transform that we can handle. */ 700 cinfo->color_transform = JCT_SUBTRACT_GREEN; 701 702 INPUT_SYNC(cinfo); 703 return TRUE; 704 } 705 706 707 /* 708 * Routines for processing APPn and COM markers. 709 * These are either saved in memory or discarded, per application request. 710 * APP0 and APP14 are specially checked to see if they are 711 * JFIF and Adobe markers, respectively. 712 */ 713 714 #define APP0_DATA_LEN 14 /* Length of interesting data in APP0 */ 715 #define APP14_DATA_LEN 12 /* Length of interesting data in APP14 */ 716 #define APPN_DATA_LEN 14 /* Must be the largest of the above!! */ 717 718 719 LOCAL(void) 720 examine_app0 (j_decompress_ptr cinfo, JOCTET FAR * data, 721 unsigned int datalen, INT32 remaining) 722 /* Examine first few bytes from an APP0. 723 * Take appropriate action if it is a JFIF marker. 724 * datalen is # of bytes at data[], remaining is length of rest of marker data. 725 */ 726 { 727 INT32 totallen = (INT32) datalen + remaining; 728 729 if (datalen >= APP0_DATA_LEN && 730 GETJOCTET(data[0]) == 0x4A && 731 GETJOCTET(data[1]) == 0x46 && 732 GETJOCTET(data[2]) == 0x49 && 733 GETJOCTET(data[3]) == 0x46 && 734 GETJOCTET(data[4]) == 0) { 735 /* Found JFIF APP0 marker: save info */ 736 cinfo->saw_JFIF_marker = TRUE; 737 cinfo->JFIF_major_version = GETJOCTET(data[5]); 738 cinfo->JFIF_minor_version = GETJOCTET(data[6]); 739 cinfo->density_unit = GETJOCTET(data[7]); 740 cinfo->X_density = (GETJOCTET(data[8]) << 8) + GETJOCTET(data[9]); 741 cinfo->Y_density = (GETJOCTET(data[10]) << 8) + GETJOCTET(data[11]); 742 /* Check version. 743 * Major version must be 1 or 2, anything else signals an incompatible 744 * change. 745 * (We used to treat this as an error, but now it's a nonfatal warning, 746 * because some bozo at Hijaak couldn't read the spec.) 747 * Minor version should be 0..2, but process anyway if newer. 748 */ 749 if (cinfo->JFIF_major_version != 1 && cinfo->JFIF_major_version != 2) 750 WARNMS2(cinfo, JWRN_JFIF_MAJOR, 751 cinfo->JFIF_major_version, cinfo->JFIF_minor_version); 752 /* Generate trace messages */ 753 TRACEMS5(cinfo, 1, JTRC_JFIF, 754 cinfo->JFIF_major_version, cinfo->JFIF_minor_version, 755 cinfo->X_density, cinfo->Y_density, cinfo->density_unit); 756 /* Validate thumbnail dimensions and issue appropriate messages */ 757 if (GETJOCTET(data[12]) | GETJOCTET(data[13])) 758 TRACEMS2(cinfo, 1, JTRC_JFIF_THUMBNAIL, 759 GETJOCTET(data[12]), GETJOCTET(data[13])); 760 totallen -= APP0_DATA_LEN; 761 if (totallen != 762 ((INT32)GETJOCTET(data[12]) * (INT32)GETJOCTET(data[13]) * (INT32) 3)) 763 TRACEMS1(cinfo, 1, JTRC_JFIF_BADTHUMBNAILSIZE, (int) totallen); 764 } else if (datalen >= 6 && 765 GETJOCTET(data[0]) == 0x4A && 766 GETJOCTET(data[1]) == 0x46 && 767 GETJOCTET(data[2]) == 0x58 && 768 GETJOCTET(data[3]) == 0x58 && 769 GETJOCTET(data[4]) == 0) { 770 /* Found JFIF "JFXX" extension APP0 marker */ 771 /* The library doesn't actually do anything with these, 772 * but we try to produce a helpful trace message. 773 */ 774 switch (GETJOCTET(data[5])) { 775 case 0x10: 776 TRACEMS1(cinfo, 1, JTRC_THUMB_JPEG, (int) totallen); 777 break; 778 case 0x11: 779 TRACEMS1(cinfo, 1, JTRC_THUMB_PALETTE, (int) totallen); 780 break; 781 case 0x13: 782 TRACEMS1(cinfo, 1, JTRC_THUMB_RGB, (int) totallen); 783 break; 784 default: 785 TRACEMS2(cinfo, 1, JTRC_JFIF_EXTENSION, 786 GETJOCTET(data[5]), (int) totallen); 787 break; 788 } 789 } else { 790 /* Start of APP0 does not match "JFIF" or "JFXX", or too short */ 791 TRACEMS1(cinfo, 1, JTRC_APP0, (int) totallen); 792 } 793 } 794 795 796 LOCAL(void) 797 examine_app14 (j_decompress_ptr cinfo, JOCTET FAR * data, 798 unsigned int datalen, INT32 remaining) 799 /* Examine first few bytes from an APP14. 800 * Take appropriate action if it is an Adobe marker. 801 * datalen is # of bytes at data[], remaining is length of rest of marker data. 802 */ 803 { 804 unsigned int version, flags0, flags1, transform; 805 806 if (datalen >= APP14_DATA_LEN && 807 GETJOCTET(data[0]) == 0x41 && 808 GETJOCTET(data[1]) == 0x64 && 809 GETJOCTET(data[2]) == 0x6F && 810 GETJOCTET(data[3]) == 0x62 && 811 GETJOCTET(data[4]) == 0x65) { 812 /* Found Adobe APP14 marker */ 813 version = (GETJOCTET(data[5]) << 8) + GETJOCTET(data[6]); 814 flags0 = (GETJOCTET(data[7]) << 8) + GETJOCTET(data[8]); 815 flags1 = (GETJOCTET(data[9]) << 8) + GETJOCTET(data[10]); 816 transform = GETJOCTET(data[11]); 817 TRACEMS4(cinfo, 1, JTRC_ADOBE, version, flags0, flags1, transform); 818 cinfo->saw_Adobe_marker = TRUE; 819 cinfo->Adobe_transform = (UINT8) transform; 820 } else { 821 /* Start of APP14 does not match "Adobe", or too short */ 822 TRACEMS1(cinfo, 1, JTRC_APP14, (int) (datalen + remaining)); 823 } 824 } 825 826 827 METHODDEF(boolean) 828 get_interesting_appn (j_decompress_ptr cinfo) 829 /* Process an APP0 or APP14 marker without saving it */ 830 { 831 INT32 length; 832 JOCTET b[APPN_DATA_LEN]; 833 unsigned int i, numtoread; 834 INPUT_VARS(cinfo); 835 836 INPUT_2BYTES(cinfo, length, return FALSE); 837 length -= 2; 838 839 /* get the interesting part of the marker data */ 840 if (length >= APPN_DATA_LEN) 841 numtoread = APPN_DATA_LEN; 842 else if (length > 0) 843 numtoread = (unsigned int) length; 844 else 845 numtoread = 0; 846 for (i = 0; i < numtoread; i++) 847 INPUT_BYTE(cinfo, b[i], return FALSE); 848 length -= numtoread; 849 850 /* process it */ 851 switch (cinfo->unread_marker) { 852 case M_APP0: 853 examine_app0(cinfo, (JOCTET FAR *) b, numtoread, length); 854 break; 855 case M_APP14: 856 examine_app14(cinfo, (JOCTET FAR *) b, numtoread, length); 857 break; 858 default: 859 /* can't get here unless jpeg_save_markers chooses wrong processor */ 860 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker); 861 break; 862 } 863 864 /* skip any remaining data -- could be lots */ 865 INPUT_SYNC(cinfo); 866 if (length > 0) 867 (*cinfo->src->skip_input_data) (cinfo, (long) length); 868 869 return TRUE; 870 } 871 872 873 #ifdef SAVE_MARKERS_SUPPORTED 874 875 METHODDEF(boolean) 876 save_marker (j_decompress_ptr cinfo) 877 /* Save an APPn or COM marker into the marker list */ 878 { 879 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 880 jpeg_saved_marker_ptr cur_marker = marker->cur_marker; 881 unsigned int bytes_read, data_length; 882 JOCTET FAR * data; 883 INT32 length = 0; 884 INPUT_VARS(cinfo); 885 886 if (cur_marker == NULL) { 887 /* begin reading a marker */ 888 INPUT_2BYTES(cinfo, length, return FALSE); 889 length -= 2; 890 if (length >= 0) { /* watch out for bogus length word */ 891 /* figure out how much we want to save */ 892 unsigned int limit; 893 if (cinfo->unread_marker == (int) M_COM) 894 limit = marker->length_limit_COM; 895 else 896 limit = marker->length_limit_APPn[cinfo->unread_marker - (int) M_APP0]; 897 if ((unsigned int) length < limit) 898 limit = (unsigned int) length; 899 /* allocate and initialize the marker item */ 900 cur_marker = (jpeg_saved_marker_ptr) 901 (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE, 902 SIZEOF(struct jpeg_marker_struct) + limit); 903 cur_marker->next = NULL; 904 cur_marker->marker = (UINT8) cinfo->unread_marker; 905 cur_marker->original_length = (unsigned int) length; 906 cur_marker->data_length = limit; 907 /* data area is just beyond the jpeg_marker_struct */ 908 data = cur_marker->data = (JOCTET FAR *) (cur_marker + 1); 909 marker->cur_marker = cur_marker; 910 marker->bytes_read = 0; 911 bytes_read = 0; 912 data_length = limit; 913 } else { 914 /* deal with bogus length word */ 915 bytes_read = data_length = 0; 916 data = NULL; 917 } 918 } else { 919 /* resume reading a marker */ 920 bytes_read = marker->bytes_read; 921 data_length = cur_marker->data_length; 922 data = cur_marker->data + bytes_read; 923 } 924 925 while (bytes_read < data_length) { 926 INPUT_SYNC(cinfo); /* move the restart point to here */ 927 marker->bytes_read = bytes_read; 928 /* If there's not at least one byte in buffer, suspend */ 929 MAKE_BYTE_AVAIL(cinfo, return FALSE); 930 /* Copy bytes with reasonable rapidity */ 931 while (bytes_read < data_length && bytes_in_buffer > 0) { 932 *data++ = *next_input_byte++; 933 bytes_in_buffer--; 934 bytes_read++; 935 } 936 } 937 938 /* Done reading what we want to read */ 939 if (cur_marker != NULL) { /* will be NULL if bogus length word */ 940 /* Add new marker to end of list */ 941 if (cinfo->marker_list == NULL) { 942 cinfo->marker_list = cur_marker; 943 } else { 944 jpeg_saved_marker_ptr prev = cinfo->marker_list; 945 while (prev->next != NULL) 946 prev = prev->next; 947 prev->next = cur_marker; 948 } 949 /* Reset pointer & calc remaining data length */ 950 data = cur_marker->data; 951 length = cur_marker->original_length - data_length; 952 } 953 /* Reset to initial state for next marker */ 954 marker->cur_marker = NULL; 955 956 /* Process the marker if interesting; else just make a generic trace msg */ 957 switch (cinfo->unread_marker) { 958 case M_APP0: 959 examine_app0(cinfo, data, data_length, length); 960 break; 961 case M_APP14: 962 examine_app14(cinfo, data, data_length, length); 963 break; 964 default: 965 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, 966 (int) (data_length + length)); 967 break; 968 } 969 970 /* skip any remaining data -- could be lots */ 971 INPUT_SYNC(cinfo); /* do before skip_input_data */ 972 if (length > 0) 973 (*cinfo->src->skip_input_data) (cinfo, (long) length); 974 975 return TRUE; 976 } 977 978 #endif /* SAVE_MARKERS_SUPPORTED */ 979 980 981 METHODDEF(boolean) 982 skip_variable (j_decompress_ptr cinfo) 983 /* Skip over an unknown or uninteresting variable-length marker */ 984 { 985 INT32 length; 986 INPUT_VARS(cinfo); 987 988 INPUT_2BYTES(cinfo, length, return FALSE); 989 length -= 2; 990 991 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, (int) length); 992 993 INPUT_SYNC(cinfo); /* do before skip_input_data */ 994 if (length > 0) 995 (*cinfo->src->skip_input_data) (cinfo, (long) length); 996 997 return TRUE; 998 } 999 1000 1001 /* 1002 * Find the next JPEG marker, save it in cinfo->unread_marker. 1003 * Returns FALSE if had to suspend before reaching a marker; 1004 * in that case cinfo->unread_marker is unchanged. 1005 * 1006 * Note that the result might not be a valid marker code, 1007 * but it will never be 0 or FF. 1008 */ 1009 1010 LOCAL(boolean) 1011 next_marker (j_decompress_ptr cinfo) 1012 { 1013 int c; 1014 INPUT_VARS(cinfo); 1015 1016 for (;;) { 1017 INPUT_BYTE(cinfo, c, return FALSE); 1018 /* Skip any non-FF bytes. 1019 * This may look a bit inefficient, but it will not occur in a valid file. 1020 * We sync after each discarded byte so that a suspending data source 1021 * can discard the byte from its buffer. 1022 */ 1023 while (c != 0xFF) { 1024 cinfo->marker->discarded_bytes++; 1025 INPUT_SYNC(cinfo); 1026 INPUT_BYTE(cinfo, c, return FALSE); 1027 } 1028 /* This loop swallows any duplicate FF bytes. Extra FFs are legal as 1029 * pad bytes, so don't count them in discarded_bytes. We assume there 1030 * will not be so many consecutive FF bytes as to overflow a suspending 1031 * data source's input buffer. 1032 */ 1033 do { 1034 INPUT_BYTE(cinfo, c, return FALSE); 1035 } while (c == 0xFF); 1036 if (c != 0) 1037 break; /* found a valid marker, exit loop */ 1038 /* Reach here if we found a stuffed-zero data sequence (FF/00). 1039 * Discard it and loop back to try again. 1040 */ 1041 cinfo->marker->discarded_bytes += 2; 1042 INPUT_SYNC(cinfo); 1043 } 1044 1045 if (cinfo->marker->discarded_bytes != 0) { 1046 WARNMS2(cinfo, JWRN_EXTRANEOUS_DATA, cinfo->marker->discarded_bytes, c); 1047 cinfo->marker->discarded_bytes = 0; 1048 } 1049 1050 cinfo->unread_marker = c; 1051 1052 INPUT_SYNC(cinfo); 1053 return TRUE; 1054 } 1055 1056 1057 LOCAL(boolean) 1058 first_marker (j_decompress_ptr cinfo) 1059 /* Like next_marker, but used to obtain the initial SOI marker. */ 1060 /* For this marker, we do not allow preceding garbage or fill; otherwise, 1061 * we might well scan an entire input file before realizing it ain't JPEG. 1062 * If an application wants to process non-JFIF files, it must seek to the 1063 * SOI before calling the JPEG library. 1064 */ 1065 { 1066 int c, c2; 1067 INPUT_VARS(cinfo); 1068 1069 INPUT_BYTE(cinfo, c, return FALSE); 1070 INPUT_BYTE(cinfo, c2, return FALSE); 1071 if (c != 0xFF || c2 != (int) M_SOI) 1072 ERREXIT2(cinfo, JERR_NO_SOI, c, c2); 1073 1074 cinfo->unread_marker = c2; 1075 1076 INPUT_SYNC(cinfo); 1077 return TRUE; 1078 } 1079 1080 1081 /* 1082 * Read markers until SOS or EOI. 1083 * 1084 * Returns same codes as are defined for jpeg_consume_input: 1085 * JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI. 1086 * 1087 * Note: This function may return a pseudo SOS marker (with zero 1088 * component number) for treat by input controller's consume_input. 1089 * consume_input itself should filter out (skip) the pseudo marker 1090 * after processing for the caller. 1091 */ 1092 1093 METHODDEF(int) 1094 read_markers (j_decompress_ptr cinfo) 1095 { 1096 /* Outer loop repeats once for each marker. */ 1097 for (;;) { 1098 /* Collect the marker proper, unless we already did. */ 1099 /* NB: first_marker() enforces the requirement that SOI appear first. */ 1100 if (cinfo->unread_marker == 0) { 1101 if (! cinfo->marker->saw_SOI) { 1102 if (! first_marker(cinfo)) 1103 return JPEG_SUSPENDED; 1104 } else { 1105 if (! next_marker(cinfo)) 1106 return JPEG_SUSPENDED; 1107 } 1108 } 1109 /* At this point cinfo->unread_marker contains the marker code and the 1110 * input point is just past the marker proper, but before any parameters. 1111 * A suspension will cause us to return with this state still true. 1112 */ 1113 switch (cinfo->unread_marker) { 1114 case M_SOI: 1115 if (! get_soi(cinfo)) 1116 return JPEG_SUSPENDED; 1117 break; 1118 1119 case M_SOF0: /* Baseline */ 1120 if (! get_sof(cinfo, TRUE, FALSE, FALSE)) 1121 return JPEG_SUSPENDED; 1122 break; 1123 1124 case M_SOF1: /* Extended sequential, Huffman */ 1125 if (! get_sof(cinfo, FALSE, FALSE, FALSE)) 1126 return JPEG_SUSPENDED; 1127 break; 1128 1129 case M_SOF2: /* Progressive, Huffman */ 1130 if (! get_sof(cinfo, FALSE, TRUE, FALSE)) 1131 return JPEG_SUSPENDED; 1132 break; 1133 1134 case M_SOF9: /* Extended sequential, arithmetic */ 1135 if (! get_sof(cinfo, FALSE, FALSE, TRUE)) 1136 return JPEG_SUSPENDED; 1137 break; 1138 1139 case M_SOF10: /* Progressive, arithmetic */ 1140 if (! get_sof(cinfo, FALSE, TRUE, TRUE)) 1141 return JPEG_SUSPENDED; 1142 break; 1143 1144 /* Currently unsupported SOFn types */ 1145 case M_SOF3: /* Lossless, Huffman */ 1146 case M_SOF5: /* Differential sequential, Huffman */ 1147 case M_SOF6: /* Differential progressive, Huffman */ 1148 case M_SOF7: /* Differential lossless, Huffman */ 1149 case M_JPG: /* Reserved for JPEG extensions */ 1150 case M_SOF11: /* Lossless, arithmetic */ 1151 case M_SOF13: /* Differential sequential, arithmetic */ 1152 case M_SOF14: /* Differential progressive, arithmetic */ 1153 case M_SOF15: /* Differential lossless, arithmetic */ 1154 ERREXIT1(cinfo, JERR_SOF_UNSUPPORTED, cinfo->unread_marker); 1155 break; 1156 1157 case M_SOS: 1158 if (! get_sos(cinfo)) 1159 return JPEG_SUSPENDED; 1160 cinfo->unread_marker = 0; /* processed the marker */ 1161 return JPEG_REACHED_SOS; 1162 1163 case M_EOI: 1164 TRACEMS(cinfo, 1, JTRC_EOI); 1165 cinfo->unread_marker = 0; /* processed the marker */ 1166 return JPEG_REACHED_EOI; 1167 1168 case M_DAC: 1169 if (! get_dac(cinfo)) 1170 return JPEG_SUSPENDED; 1171 break; 1172 1173 case M_DHT: 1174 if (! get_dht(cinfo)) 1175 return JPEG_SUSPENDED; 1176 break; 1177 1178 case M_DQT: 1179 if (! get_dqt(cinfo)) 1180 return JPEG_SUSPENDED; 1181 break; 1182 1183 case M_DRI: 1184 if (! get_dri(cinfo)) 1185 return JPEG_SUSPENDED; 1186 break; 1187 1188 case M_JPG8: 1189 if (! get_lse(cinfo)) 1190 return JPEG_SUSPENDED; 1191 break; 1192 1193 case M_APP0: 1194 case M_APP1: 1195 case M_APP2: 1196 case M_APP3: 1197 case M_APP4: 1198 case M_APP5: 1199 case M_APP6: 1200 case M_APP7: 1201 case M_APP8: 1202 case M_APP9: 1203 case M_APP10: 1204 case M_APP11: 1205 case M_APP12: 1206 case M_APP13: 1207 case M_APP14: 1208 case M_APP15: 1209 if (! (*((my_marker_ptr) cinfo->marker)->process_APPn[ 1210 cinfo->unread_marker - (int) M_APP0]) (cinfo)) 1211 return JPEG_SUSPENDED; 1212 break; 1213 1214 case M_COM: 1215 if (! (*((my_marker_ptr) cinfo->marker)->process_COM) (cinfo)) 1216 return JPEG_SUSPENDED; 1217 break; 1218 1219 case M_RST0: /* these are all parameterless */ 1220 case M_RST1: 1221 case M_RST2: 1222 case M_RST3: 1223 case M_RST4: 1224 case M_RST5: 1225 case M_RST6: 1226 case M_RST7: 1227 case M_TEM: 1228 TRACEMS1(cinfo, 1, JTRC_PARMLESS_MARKER, cinfo->unread_marker); 1229 break; 1230 1231 case M_DNL: /* Ignore DNL ... perhaps the wrong thing */ 1232 if (! skip_variable(cinfo)) 1233 return JPEG_SUSPENDED; 1234 break; 1235 1236 default: /* must be DHP, EXP, JPGn, or RESn */ 1237 /* For now, we treat the reserved markers as fatal errors since they are 1238 * likely to be used to signal incompatible JPEG Part 3 extensions. 1239 * Once the JPEG 3 version-number marker is well defined, this code 1240 * ought to change! 1241 */ 1242 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker); 1243 break; 1244 } 1245 /* Successfully processed marker, so reset state variable */ 1246 cinfo->unread_marker = 0; 1247 } /* end loop */ 1248 } 1249 1250 1251 /* 1252 * Read a restart marker, which is expected to appear next in the datastream; 1253 * if the marker is not there, take appropriate recovery action. 1254 * Returns FALSE if suspension is required. 1255 * 1256 * This is called by the entropy decoder after it has read an appropriate 1257 * number of MCUs. cinfo->unread_marker may be nonzero if the entropy decoder 1258 * has already read a marker from the data source. Under normal conditions 1259 * cinfo->unread_marker will be reset to 0 before returning; if not reset, 1260 * it holds a marker which the decoder will be unable to read past. 1261 */ 1262 1263 METHODDEF(boolean) 1264 read_restart_marker (j_decompress_ptr cinfo) 1265 { 1266 /* Obtain a marker unless we already did. */ 1267 /* Note that next_marker will complain if it skips any data. */ 1268 if (cinfo->unread_marker == 0) { 1269 if (! next_marker(cinfo)) 1270 return FALSE; 1271 } 1272 1273 if (cinfo->unread_marker == 1274 ((int) M_RST0 + cinfo->marker->next_restart_num)) { 1275 /* Normal case --- swallow the marker and let entropy decoder continue */ 1276 TRACEMS1(cinfo, 3, JTRC_RST, cinfo->marker->next_restart_num); 1277 cinfo->unread_marker = 0; 1278 } else { 1279 /* Uh-oh, the restart markers have been messed up. */ 1280 /* Let the data source manager determine how to resync. */ 1281 if (! (*cinfo->src->resync_to_restart) (cinfo, 1282 cinfo->marker->next_restart_num)) 1283 return FALSE; 1284 } 1285 1286 /* Update next-restart state */ 1287 cinfo->marker->next_restart_num = (cinfo->marker->next_restart_num + 1) & 7; 1288 1289 return TRUE; 1290 } 1291 1292 1293 /* 1294 * This is the default resync_to_restart method for data source managers 1295 * to use if they don't have any better approach. Some data source managers 1296 * may be able to back up, or may have additional knowledge about the data 1297 * which permits a more intelligent recovery strategy; such managers would 1298 * presumably supply their own resync method. 1299 * 1300 * read_restart_marker calls resync_to_restart if it finds a marker other than 1301 * the restart marker it was expecting. (This code is *not* used unless 1302 * a nonzero restart interval has been declared.) cinfo->unread_marker is 1303 * the marker code actually found (might be anything, except 0 or FF). 1304 * The desired restart marker number (0..7) is passed as a parameter. 1305 * This routine is supposed to apply whatever error recovery strategy seems 1306 * appropriate in order to position the input stream to the next data segment. 1307 * Note that cinfo->unread_marker is treated as a marker appearing before 1308 * the current data-source input point; usually it should be reset to zero 1309 * before returning. 1310 * Returns FALSE if suspension is required. 1311 * 1312 * This implementation is substantially constrained by wanting to treat the 1313 * input as a data stream; this means we can't back up. Therefore, we have 1314 * only the following actions to work with: 1315 * 1. Simply discard the marker and let the entropy decoder resume at next 1316 * byte of file. 1317 * 2. Read forward until we find another marker, discarding intervening 1318 * data. (In theory we could look ahead within the current bufferload, 1319 * without having to discard data if we don't find the desired marker. 1320 * This idea is not implemented here, in part because it makes behavior 1321 * dependent on buffer size and chance buffer-boundary positions.) 1322 * 3. Leave the marker unread (by failing to zero cinfo->unread_marker). 1323 * This will cause the entropy decoder to process an empty data segment, 1324 * inserting dummy zeroes, and then we will reprocess the marker. 1325 * 1326 * #2 is appropriate if we think the desired marker lies ahead, while #3 is 1327 * appropriate if the found marker is a future restart marker (indicating 1328 * that we have missed the desired restart marker, probably because it got 1329 * corrupted). 1330 * We apply #2 or #3 if the found marker is a restart marker no more than 1331 * two counts behind or ahead of the expected one. We also apply #2 if the 1332 * found marker is not a legal JPEG marker code (it's certainly bogus data). 1333 * If the found marker is a restart marker more than 2 counts away, we do #1 1334 * (too much risk that the marker is erroneous; with luck we will be able to 1335 * resync at some future point). 1336 * For any valid non-restart JPEG marker, we apply #3. This keeps us from 1337 * overrunning the end of a scan. An implementation limited to single-scan 1338 * files might find it better to apply #2 for markers other than EOI, since 1339 * any other marker would have to be bogus data in that case. 1340 */ 1341 1342 GLOBAL(boolean) 1343 jpeg_resync_to_restart (j_decompress_ptr cinfo, int desired) 1344 { 1345 int marker = cinfo->unread_marker; 1346 int action = 1; 1347 1348 /* Always put up a warning. */ 1349 WARNMS2(cinfo, JWRN_MUST_RESYNC, marker, desired); 1350 1351 /* Outer loop handles repeated decision after scanning forward. */ 1352 for (;;) { 1353 if (marker < (int) M_SOF0) 1354 action = 2; /* invalid marker */ 1355 else if (marker < (int) M_RST0 || marker > (int) M_RST7) 1356 action = 3; /* valid non-restart marker */ 1357 else { 1358 if (marker == ((int) M_RST0 + ((desired+1) & 7)) || 1359 marker == ((int) M_RST0 + ((desired+2) & 7))) 1360 action = 3; /* one of the next two expected restarts */ 1361 else if (marker == ((int) M_RST0 + ((desired-1) & 7)) || 1362 marker == ((int) M_RST0 + ((desired-2) & 7))) 1363 action = 2; /* a prior restart, so advance */ 1364 else 1365 action = 1; /* desired restart or too far away */ 1366 } 1367 TRACEMS2(cinfo, 4, JTRC_RECOVERY_ACTION, marker, action); 1368 switch (action) { 1369 case 1: 1370 /* Discard marker and let entropy decoder resume processing. */ 1371 cinfo->unread_marker = 0; 1372 return TRUE; 1373 case 2: 1374 /* Scan to the next marker, and repeat the decision loop. */ 1375 if (! next_marker(cinfo)) 1376 return FALSE; 1377 marker = cinfo->unread_marker; 1378 break; 1379 case 3: 1380 /* Return without advancing past this marker. */ 1381 /* Entropy decoder will be forced to process an empty segment. */ 1382 return TRUE; 1383 } 1384 } /* end loop */ 1385 } 1386 1387 1388 /* 1389 * Reset marker processing state to begin a fresh datastream. 1390 */ 1391 1392 METHODDEF(void) 1393 reset_marker_reader (j_decompress_ptr cinfo) 1394 { 1395 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 1396 1397 cinfo->comp_info = NULL; /* until allocated by get_sof */ 1398 cinfo->input_scan_number = 0; /* no SOS seen yet */ 1399 cinfo->unread_marker = 0; /* no pending marker */ 1400 marker->pub.saw_SOI = FALSE; /* set internal state too */ 1401 marker->pub.saw_SOF = FALSE; 1402 marker->pub.discarded_bytes = 0; 1403 marker->cur_marker = NULL; 1404 } 1405 1406 1407 /* 1408 * Initialize the marker reader module. 1409 * This is called only once, when the decompression object is created. 1410 */ 1411 1412 GLOBAL(void) 1413 jinit_marker_reader (j_decompress_ptr cinfo) 1414 { 1415 my_marker_ptr marker; 1416 int i; 1417 1418 /* Create subobject in permanent pool */ 1419 marker = (my_marker_ptr) 1420 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT, 1421 SIZEOF(my_marker_reader)); 1422 cinfo->marker = &marker->pub; 1423 /* Initialize public method pointers */ 1424 marker->pub.reset_marker_reader = reset_marker_reader; 1425 marker->pub.read_markers = read_markers; 1426 marker->pub.read_restart_marker = read_restart_marker; 1427 /* Initialize COM/APPn processing. 1428 * By default, we examine and then discard APP0 and APP14, 1429 * but simply discard COM and all other APPn. 1430 */ 1431 marker->process_COM = skip_variable; 1432 marker->length_limit_COM = 0; 1433 for (i = 0; i < 16; i++) { 1434 marker->process_APPn[i] = skip_variable; 1435 marker->length_limit_APPn[i] = 0; 1436 } 1437 marker->process_APPn[0] = get_interesting_appn; 1438 marker->process_APPn[14] = get_interesting_appn; 1439 /* Reset marker processing state */ 1440 reset_marker_reader(cinfo); 1441 } 1442 1443 1444 /* 1445 * Control saving of COM and APPn markers into marker_list. 1446 */ 1447 1448 #ifdef SAVE_MARKERS_SUPPORTED 1449 1450 GLOBAL(void) 1451 jpeg_save_markers (j_decompress_ptr cinfo, int marker_code, 1452 unsigned int length_limit) 1453 { 1454 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 1455 long maxlength; 1456 jpeg_marker_parser_method processor; 1457 1458 /* Length limit mustn't be larger than what we can allocate 1459 * (should only be a concern in a 16-bit environment). 1460 */ 1461 maxlength = cinfo->mem->max_alloc_chunk - SIZEOF(struct jpeg_marker_struct); 1462 if (((long) length_limit) > maxlength) 1463 length_limit = (unsigned int) maxlength; 1464 1465 /* Choose processor routine to use. 1466 * APP0/APP14 have special requirements. 1467 */ 1468 if (length_limit) { 1469 processor = save_marker; 1470 /* If saving APP0/APP14, save at least enough for our internal use. */ 1471 if (marker_code == (int) M_APP0 && length_limit < APP0_DATA_LEN) 1472 length_limit = APP0_DATA_LEN; 1473 else if (marker_code == (int) M_APP14 && length_limit < APP14_DATA_LEN) 1474 length_limit = APP14_DATA_LEN; 1475 } else { 1476 processor = skip_variable; 1477 /* If discarding APP0/APP14, use our regular on-the-fly processor. */ 1478 if (marker_code == (int) M_APP0 || marker_code == (int) M_APP14) 1479 processor = get_interesting_appn; 1480 } 1481 1482 if (marker_code == (int) M_COM) { 1483 marker->process_COM = processor; 1484 marker->length_limit_COM = length_limit; 1485 } else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15) { 1486 marker->process_APPn[marker_code - (int) M_APP0] = processor; 1487 marker->length_limit_APPn[marker_code - (int) M_APP0] = length_limit; 1488 } else 1489 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code); 1490 } 1491 1492 #endif /* SAVE_MARKERS_SUPPORTED */ 1493 1494 1495 /* 1496 * Install a special processing method for COM or APPn markers. 1497 */ 1498 1499 GLOBAL(void) 1500 jpeg_set_marker_processor (j_decompress_ptr cinfo, int marker_code, 1501 jpeg_marker_parser_method routine) 1502 { 1503 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 1504 1505 if (marker_code == (int) M_COM) 1506 marker->process_COM = routine; 1507 else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15) 1508 marker->process_APPn[marker_code - (int) M_APP0] = routine; 1509 else 1510 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code); 1511 } 1512