1 /* 2 * jdmarker.c 3 * 4 * Copyright (C) 1991-1998, Thomas G. Lane. 5 * Modified 2009-2012 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 for (ci = 0; ci < i; ci++) { 354 if (c == cinfo->cur_comp_info[ci]->component_id) { 355 c = cinfo->cur_comp_info[0]->component_id; 356 for (ci = 1; ci < i; ci++) { 357 compptr = cinfo->cur_comp_info[ci]; 358 if (compptr->component_id > c) c = compptr->component_id; 359 } 360 c++; 361 break; 362 } 363 } 364 365 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 366 ci++, compptr++) { 367 if (c == compptr->component_id) 368 goto id_found; 369 } 370 371 ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, c); 372 373 id_found: 374 375 cinfo->cur_comp_info[i] = compptr; 376 INPUT_BYTE(cinfo, c, return FALSE); 377 compptr->dc_tbl_no = (c >> 4) & 15; 378 compptr->ac_tbl_no = (c ) & 15; 379 380 TRACEMS3(cinfo, 1, JTRC_SOS_COMPONENT, compptr->component_id, 381 compptr->dc_tbl_no, compptr->ac_tbl_no); 382 } 383 384 /* Collect the additional scan parameters Ss, Se, Ah/Al. */ 385 INPUT_BYTE(cinfo, c, return FALSE); 386 cinfo->Ss = c; 387 INPUT_BYTE(cinfo, c, return FALSE); 388 cinfo->Se = c; 389 INPUT_BYTE(cinfo, c, return FALSE); 390 cinfo->Ah = (c >> 4) & 15; 391 cinfo->Al = (c ) & 15; 392 393 TRACEMS4(cinfo, 1, JTRC_SOS_PARAMS, cinfo->Ss, cinfo->Se, 394 cinfo->Ah, cinfo->Al); 395 396 /* Prepare to scan data & restart markers */ 397 cinfo->marker->next_restart_num = 0; 398 399 /* Count another (non-pseudo) SOS marker */ 400 if (n) cinfo->input_scan_number++; 401 402 INPUT_SYNC(cinfo); 403 return TRUE; 404 } 405 406 407 #ifdef D_ARITH_CODING_SUPPORTED 408 409 LOCAL(boolean) 410 get_dac (j_decompress_ptr cinfo) 411 /* Process a DAC marker */ 412 { 413 INT32 length; 414 int index, val; 415 INPUT_VARS(cinfo); 416 417 INPUT_2BYTES(cinfo, length, return FALSE); 418 length -= 2; 419 420 while (length > 0) { 421 INPUT_BYTE(cinfo, index, return FALSE); 422 INPUT_BYTE(cinfo, val, return FALSE); 423 424 length -= 2; 425 426 TRACEMS2(cinfo, 1, JTRC_DAC, index, val); 427 428 if (index < 0 || index >= (2*NUM_ARITH_TBLS)) 429 ERREXIT1(cinfo, JERR_DAC_INDEX, index); 430 431 if (index >= NUM_ARITH_TBLS) { /* define AC table */ 432 cinfo->arith_ac_K[index-NUM_ARITH_TBLS] = (UINT8) val; 433 } else { /* define DC table */ 434 cinfo->arith_dc_L[index] = (UINT8) (val & 0x0F); 435 cinfo->arith_dc_U[index] = (UINT8) (val >> 4); 436 if (cinfo->arith_dc_L[index] > cinfo->arith_dc_U[index]) 437 ERREXIT1(cinfo, JERR_DAC_VALUE, val); 438 } 439 } 440 441 if (length != 0) 442 ERREXIT(cinfo, JERR_BAD_LENGTH); 443 444 INPUT_SYNC(cinfo); 445 return TRUE; 446 } 447 448 #else /* ! D_ARITH_CODING_SUPPORTED */ 449 450 #define get_dac(cinfo) skip_variable(cinfo) 451 452 #endif /* D_ARITH_CODING_SUPPORTED */ 453 454 455 LOCAL(boolean) 456 get_dht (j_decompress_ptr cinfo) 457 /* Process a DHT marker */ 458 { 459 INT32 length; 460 UINT8 bits[17]; 461 UINT8 huffval[256]; 462 int i, index, count; 463 JHUFF_TBL **htblptr; 464 INPUT_VARS(cinfo); 465 466 INPUT_2BYTES(cinfo, length, return FALSE); 467 length -= 2; 468 469 while (length > 16) { 470 INPUT_BYTE(cinfo, index, return FALSE); 471 472 TRACEMS1(cinfo, 1, JTRC_DHT, index); 473 474 bits[0] = 0; 475 count = 0; 476 for (i = 1; i <= 16; i++) { 477 INPUT_BYTE(cinfo, bits[i], return FALSE); 478 count += bits[i]; 479 } 480 481 length -= 1 + 16; 482 483 TRACEMS8(cinfo, 2, JTRC_HUFFBITS, 484 bits[1], bits[2], bits[3], bits[4], 485 bits[5], bits[6], bits[7], bits[8]); 486 TRACEMS8(cinfo, 2, JTRC_HUFFBITS, 487 bits[9], bits[10], bits[11], bits[12], 488 bits[13], bits[14], bits[15], bits[16]); 489 490 /* Here we just do minimal validation of the counts to avoid walking 491 * off the end of our table space. jdhuff.c will check more carefully. 492 */ 493 if (count > 256 || ((INT32) count) > length) 494 ERREXIT(cinfo, JERR_BAD_HUFF_TABLE); 495 496 for (i = 0; i < count; i++) 497 INPUT_BYTE(cinfo, huffval[i], return FALSE); 498 499 length -= count; 500 501 if (index & 0x10) { /* AC table definition */ 502 index -= 0x10; 503 htblptr = &cinfo->ac_huff_tbl_ptrs[index]; 504 } else { /* DC table definition */ 505 htblptr = &cinfo->dc_huff_tbl_ptrs[index]; 506 } 507 508 if (index < 0 || index >= NUM_HUFF_TBLS) 509 ERREXIT1(cinfo, JERR_DHT_INDEX, index); 510 511 if (*htblptr == NULL) 512 *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo); 513 514 MEMCOPY((*htblptr)->bits, bits, SIZEOF((*htblptr)->bits)); 515 MEMCOPY((*htblptr)->huffval, huffval, SIZEOF((*htblptr)->huffval)); 516 } 517 518 if (length != 0) 519 ERREXIT(cinfo, JERR_BAD_LENGTH); 520 521 INPUT_SYNC(cinfo); 522 return TRUE; 523 } 524 525 526 LOCAL(boolean) 527 get_dqt (j_decompress_ptr cinfo) 528 /* Process a DQT marker */ 529 { 530 INT32 length, count, i; 531 int n, prec; 532 unsigned int tmp; 533 JQUANT_TBL *quant_ptr; 534 const int *natural_order; 535 INPUT_VARS(cinfo); 536 537 INPUT_2BYTES(cinfo, length, return FALSE); 538 length -= 2; 539 540 while (length > 0) { 541 length--; 542 INPUT_BYTE(cinfo, n, return FALSE); 543 prec = n >> 4; 544 n &= 0x0F; 545 546 TRACEMS2(cinfo, 1, JTRC_DQT, n, prec); 547 548 if (n >= NUM_QUANT_TBLS) 549 ERREXIT1(cinfo, JERR_DQT_INDEX, n); 550 551 if (cinfo->quant_tbl_ptrs[n] == NULL) 552 cinfo->quant_tbl_ptrs[n] = jpeg_alloc_quant_table((j_common_ptr) cinfo); 553 quant_ptr = cinfo->quant_tbl_ptrs[n]; 554 555 if (prec) { 556 if (length < DCTSIZE2 * 2) { 557 /* Initialize full table for safety. */ 558 for (i = 0; i < DCTSIZE2; i++) { 559 quant_ptr->quantval[i] = 1; 560 } 561 count = length >> 1; 562 } else 563 count = DCTSIZE2; 564 } else { 565 if (length < DCTSIZE2) { 566 /* Initialize full table for safety. */ 567 for (i = 0; i < DCTSIZE2; i++) { 568 quant_ptr->quantval[i] = 1; 569 } 570 count = length; 571 } else 572 count = DCTSIZE2; 573 } 574 575 switch (count) { 576 case (2*2): natural_order = jpeg_natural_order2; break; 577 case (3*3): natural_order = jpeg_natural_order3; break; 578 case (4*4): natural_order = jpeg_natural_order4; break; 579 case (5*5): natural_order = jpeg_natural_order5; break; 580 case (6*6): natural_order = jpeg_natural_order6; break; 581 case (7*7): natural_order = jpeg_natural_order7; break; 582 default: natural_order = jpeg_natural_order; break; 583 } 584 585 for (i = 0; i < count; i++) { 586 if (prec) 587 INPUT_2BYTES(cinfo, tmp, return FALSE); 588 else 589 INPUT_BYTE(cinfo, tmp, return FALSE); 590 /* We convert the zigzag-order table to natural array order. */ 591 quant_ptr->quantval[natural_order[i]] = (UINT16) tmp; 592 } 593 594 if (cinfo->err->trace_level >= 2) { 595 for (i = 0; i < DCTSIZE2; i += 8) { 596 TRACEMS8(cinfo, 2, JTRC_QUANTVALS, 597 quant_ptr->quantval[i], quant_ptr->quantval[i+1], 598 quant_ptr->quantval[i+2], quant_ptr->quantval[i+3], 599 quant_ptr->quantval[i+4], quant_ptr->quantval[i+5], 600 quant_ptr->quantval[i+6], quant_ptr->quantval[i+7]); 601 } 602 } 603 604 length -= count; 605 if (prec) length -= count; 606 } 607 608 if (length != 0) 609 ERREXIT(cinfo, JERR_BAD_LENGTH); 610 611 INPUT_SYNC(cinfo); 612 return TRUE; 613 } 614 615 616 LOCAL(boolean) 617 get_dri (j_decompress_ptr cinfo) 618 /* Process a DRI marker */ 619 { 620 INT32 length; 621 unsigned int tmp; 622 INPUT_VARS(cinfo); 623 624 INPUT_2BYTES(cinfo, length, return FALSE); 625 626 if (length != 4) 627 ERREXIT(cinfo, JERR_BAD_LENGTH); 628 629 INPUT_2BYTES(cinfo, tmp, return FALSE); 630 631 TRACEMS1(cinfo, 1, JTRC_DRI, tmp); 632 633 cinfo->restart_interval = tmp; 634 635 INPUT_SYNC(cinfo); 636 return TRUE; 637 } 638 639 640 LOCAL(boolean) 641 get_lse (j_decompress_ptr cinfo) 642 /* Process an LSE marker */ 643 { 644 INT32 length; 645 unsigned int tmp; 646 int cid; 647 INPUT_VARS(cinfo); 648 649 if (! cinfo->marker->saw_SOF) 650 ERREXITS(cinfo, JERR_SOF_BEFORE, "LSE"); 651 652 if (cinfo->num_components < 3) goto bad; 653 654 INPUT_2BYTES(cinfo, length, return FALSE); 655 656 if (length != 24) 657 ERREXIT(cinfo, JERR_BAD_LENGTH); 658 659 INPUT_BYTE(cinfo, tmp, return FALSE); 660 if (tmp != 0x0D) /* ID inverse transform specification */ 661 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker); 662 INPUT_2BYTES(cinfo, tmp, return FALSE); 663 if (tmp != MAXJSAMPLE) goto bad; /* MAXTRANS */ 664 INPUT_BYTE(cinfo, tmp, return FALSE); 665 if (tmp != 3) goto bad; /* Nt=3 */ 666 INPUT_BYTE(cinfo, cid, return FALSE); 667 if (cid != cinfo->comp_info[1].component_id) goto bad; 668 INPUT_BYTE(cinfo, cid, return FALSE); 669 if (cid != cinfo->comp_info[0].component_id) goto bad; 670 INPUT_BYTE(cinfo, cid, return FALSE); 671 if (cid != cinfo->comp_info[2].component_id) goto bad; 672 INPUT_BYTE(cinfo, tmp, return FALSE); 673 if (tmp != 0x80) goto bad; /* F1: CENTER1=1, NORM1=0 */ 674 INPUT_2BYTES(cinfo, tmp, return FALSE); 675 if (tmp != 0) goto bad; /* A(1,1)=0 */ 676 INPUT_2BYTES(cinfo, tmp, return FALSE); 677 if (tmp != 0) goto bad; /* A(1,2)=0 */ 678 INPUT_BYTE(cinfo, tmp, return FALSE); 679 if (tmp != 0) goto bad; /* F2: CENTER2=0, NORM2=0 */ 680 INPUT_2BYTES(cinfo, tmp, return FALSE); 681 if (tmp != 1) goto bad; /* A(2,1)=1 */ 682 INPUT_2BYTES(cinfo, tmp, return FALSE); 683 if (tmp != 0) goto bad; /* A(2,2)=0 */ 684 INPUT_BYTE(cinfo, tmp, return FALSE); 685 if (tmp != 0) goto bad; /* F3: CENTER3=0, NORM3=0 */ 686 INPUT_2BYTES(cinfo, tmp, return FALSE); 687 if (tmp != 1) goto bad; /* A(3,1)=1 */ 688 INPUT_2BYTES(cinfo, tmp, return FALSE); 689 if (tmp != 0) { /* A(3,2)=0 */ 690 bad: 691 ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL); 692 } 693 694 /* OK, valid transform that we can handle. */ 695 cinfo->color_transform = JCT_SUBTRACT_GREEN; 696 697 INPUT_SYNC(cinfo); 698 return TRUE; 699 } 700 701 702 /* 703 * Routines for processing APPn and COM markers. 704 * These are either saved in memory or discarded, per application request. 705 * APP0 and APP14 are specially checked to see if they are 706 * JFIF and Adobe markers, respectively. 707 */ 708 709 #define APP0_DATA_LEN 14 /* Length of interesting data in APP0 */ 710 #define APP14_DATA_LEN 12 /* Length of interesting data in APP14 */ 711 #define APPN_DATA_LEN 14 /* Must be the largest of the above!! */ 712 713 714 LOCAL(void) 715 examine_app0 (j_decompress_ptr cinfo, JOCTET FAR * data, 716 unsigned int datalen, INT32 remaining) 717 /* Examine first few bytes from an APP0. 718 * Take appropriate action if it is a JFIF marker. 719 * datalen is # of bytes at data[], remaining is length of rest of marker data. 720 */ 721 { 722 INT32 totallen = (INT32) datalen + remaining; 723 724 if (datalen >= APP0_DATA_LEN && 725 GETJOCTET(data[0]) == 0x4A && 726 GETJOCTET(data[1]) == 0x46 && 727 GETJOCTET(data[2]) == 0x49 && 728 GETJOCTET(data[3]) == 0x46 && 729 GETJOCTET(data[4]) == 0) { 730 /* Found JFIF APP0 marker: save info */ 731 cinfo->saw_JFIF_marker = TRUE; 732 cinfo->JFIF_major_version = GETJOCTET(data[5]); 733 cinfo->JFIF_minor_version = GETJOCTET(data[6]); 734 cinfo->density_unit = GETJOCTET(data[7]); 735 cinfo->X_density = (GETJOCTET(data[8]) << 8) + GETJOCTET(data[9]); 736 cinfo->Y_density = (GETJOCTET(data[10]) << 8) + GETJOCTET(data[11]); 737 /* Check version. 738 * Major version must be 1, anything else signals an incompatible change. 739 * (We used to treat this as an error, but now it's a nonfatal warning, 740 * because some bozo at Hijaak couldn't read the spec.) 741 * Minor version should be 0..2, but process anyway if newer. 742 */ 743 if (cinfo->JFIF_major_version != 1) 744 WARNMS2(cinfo, JWRN_JFIF_MAJOR, 745 cinfo->JFIF_major_version, cinfo->JFIF_minor_version); 746 /* Generate trace messages */ 747 TRACEMS5(cinfo, 1, JTRC_JFIF, 748 cinfo->JFIF_major_version, cinfo->JFIF_minor_version, 749 cinfo->X_density, cinfo->Y_density, cinfo->density_unit); 750 /* Validate thumbnail dimensions and issue appropriate messages */ 751 if (GETJOCTET(data[12]) | GETJOCTET(data[13])) 752 TRACEMS2(cinfo, 1, JTRC_JFIF_THUMBNAIL, 753 GETJOCTET(data[12]), GETJOCTET(data[13])); 754 totallen -= APP0_DATA_LEN; 755 if (totallen != 756 ((INT32)GETJOCTET(data[12]) * (INT32)GETJOCTET(data[13]) * (INT32) 3)) 757 TRACEMS1(cinfo, 1, JTRC_JFIF_BADTHUMBNAILSIZE, (int) totallen); 758 } else if (datalen >= 6 && 759 GETJOCTET(data[0]) == 0x4A && 760 GETJOCTET(data[1]) == 0x46 && 761 GETJOCTET(data[2]) == 0x58 && 762 GETJOCTET(data[3]) == 0x58 && 763 GETJOCTET(data[4]) == 0) { 764 /* Found JFIF "JFXX" extension APP0 marker */ 765 /* The library doesn't actually do anything with these, 766 * but we try to produce a helpful trace message. 767 */ 768 switch (GETJOCTET(data[5])) { 769 case 0x10: 770 TRACEMS1(cinfo, 1, JTRC_THUMB_JPEG, (int) totallen); 771 break; 772 case 0x11: 773 TRACEMS1(cinfo, 1, JTRC_THUMB_PALETTE, (int) totallen); 774 break; 775 case 0x13: 776 TRACEMS1(cinfo, 1, JTRC_THUMB_RGB, (int) totallen); 777 break; 778 default: 779 TRACEMS2(cinfo, 1, JTRC_JFIF_EXTENSION, 780 GETJOCTET(data[5]), (int) totallen); 781 break; 782 } 783 } else { 784 /* Start of APP0 does not match "JFIF" or "JFXX", or too short */ 785 TRACEMS1(cinfo, 1, JTRC_APP0, (int) totallen); 786 } 787 } 788 789 790 LOCAL(void) 791 examine_app14 (j_decompress_ptr cinfo, JOCTET FAR * data, 792 unsigned int datalen, INT32 remaining) 793 /* Examine first few bytes from an APP14. 794 * Take appropriate action if it is an Adobe marker. 795 * datalen is # of bytes at data[], remaining is length of rest of marker data. 796 */ 797 { 798 unsigned int version, flags0, flags1, transform; 799 800 if (datalen >= APP14_DATA_LEN && 801 GETJOCTET(data[0]) == 0x41 && 802 GETJOCTET(data[1]) == 0x64 && 803 GETJOCTET(data[2]) == 0x6F && 804 GETJOCTET(data[3]) == 0x62 && 805 GETJOCTET(data[4]) == 0x65) { 806 /* Found Adobe APP14 marker */ 807 version = (GETJOCTET(data[5]) << 8) + GETJOCTET(data[6]); 808 flags0 = (GETJOCTET(data[7]) << 8) + GETJOCTET(data[8]); 809 flags1 = (GETJOCTET(data[9]) << 8) + GETJOCTET(data[10]); 810 transform = GETJOCTET(data[11]); 811 TRACEMS4(cinfo, 1, JTRC_ADOBE, version, flags0, flags1, transform); 812 cinfo->saw_Adobe_marker = TRUE; 813 cinfo->Adobe_transform = (UINT8) transform; 814 } else { 815 /* Start of APP14 does not match "Adobe", or too short */ 816 TRACEMS1(cinfo, 1, JTRC_APP14, (int) (datalen + remaining)); 817 } 818 } 819 820 821 METHODDEF(boolean) 822 get_interesting_appn (j_decompress_ptr cinfo) 823 /* Process an APP0 or APP14 marker without saving it */ 824 { 825 INT32 length; 826 JOCTET b[APPN_DATA_LEN]; 827 unsigned int i, numtoread; 828 INPUT_VARS(cinfo); 829 830 INPUT_2BYTES(cinfo, length, return FALSE); 831 length -= 2; 832 833 /* get the interesting part of the marker data */ 834 if (length >= APPN_DATA_LEN) 835 numtoread = APPN_DATA_LEN; 836 else if (length > 0) 837 numtoread = (unsigned int) length; 838 else 839 numtoread = 0; 840 for (i = 0; i < numtoread; i++) 841 INPUT_BYTE(cinfo, b[i], return FALSE); 842 length -= numtoread; 843 844 /* process it */ 845 switch (cinfo->unread_marker) { 846 case M_APP0: 847 examine_app0(cinfo, (JOCTET FAR *) b, numtoread, length); 848 break; 849 case M_APP14: 850 examine_app14(cinfo, (JOCTET FAR *) b, numtoread, length); 851 break; 852 default: 853 /* can't get here unless jpeg_save_markers chooses wrong processor */ 854 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker); 855 break; 856 } 857 858 /* skip any remaining data -- could be lots */ 859 INPUT_SYNC(cinfo); 860 if (length > 0) 861 (*cinfo->src->skip_input_data) (cinfo, (long) length); 862 863 return TRUE; 864 } 865 866 867 #ifdef SAVE_MARKERS_SUPPORTED 868 869 METHODDEF(boolean) 870 save_marker (j_decompress_ptr cinfo) 871 /* Save an APPn or COM marker into the marker list */ 872 { 873 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 874 jpeg_saved_marker_ptr cur_marker = marker->cur_marker; 875 unsigned int bytes_read, data_length; 876 JOCTET FAR * data; 877 INT32 length = 0; 878 INPUT_VARS(cinfo); 879 880 if (cur_marker == NULL) { 881 /* begin reading a marker */ 882 INPUT_2BYTES(cinfo, length, return FALSE); 883 length -= 2; 884 if (length >= 0) { /* watch out for bogus length word */ 885 /* figure out how much we want to save */ 886 unsigned int limit; 887 if (cinfo->unread_marker == (int) M_COM) 888 limit = marker->length_limit_COM; 889 else 890 limit = marker->length_limit_APPn[cinfo->unread_marker - (int) M_APP0]; 891 if ((unsigned int) length < limit) 892 limit = (unsigned int) length; 893 /* allocate and initialize the marker item */ 894 cur_marker = (jpeg_saved_marker_ptr) 895 (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE, 896 SIZEOF(struct jpeg_marker_struct) + limit); 897 cur_marker->next = NULL; 898 cur_marker->marker = (UINT8) cinfo->unread_marker; 899 cur_marker->original_length = (unsigned int) length; 900 cur_marker->data_length = limit; 901 /* data area is just beyond the jpeg_marker_struct */ 902 data = cur_marker->data = (JOCTET FAR *) (cur_marker + 1); 903 marker->cur_marker = cur_marker; 904 marker->bytes_read = 0; 905 bytes_read = 0; 906 data_length = limit; 907 } else { 908 /* deal with bogus length word */ 909 bytes_read = data_length = 0; 910 data = NULL; 911 } 912 } else { 913 /* resume reading a marker */ 914 bytes_read = marker->bytes_read; 915 data_length = cur_marker->data_length; 916 data = cur_marker->data + bytes_read; 917 } 918 919 while (bytes_read < data_length) { 920 INPUT_SYNC(cinfo); /* move the restart point to here */ 921 marker->bytes_read = bytes_read; 922 /* If there's not at least one byte in buffer, suspend */ 923 MAKE_BYTE_AVAIL(cinfo, return FALSE); 924 /* Copy bytes with reasonable rapidity */ 925 while (bytes_read < data_length && bytes_in_buffer > 0) { 926 *data++ = *next_input_byte++; 927 bytes_in_buffer--; 928 bytes_read++; 929 } 930 } 931 932 /* Done reading what we want to read */ 933 if (cur_marker != NULL) { /* will be NULL if bogus length word */ 934 /* Add new marker to end of list */ 935 if (cinfo->marker_list == NULL) { 936 cinfo->marker_list = cur_marker; 937 } else { 938 jpeg_saved_marker_ptr prev = cinfo->marker_list; 939 while (prev->next != NULL) 940 prev = prev->next; 941 prev->next = cur_marker; 942 } 943 /* Reset pointer & calc remaining data length */ 944 data = cur_marker->data; 945 length = cur_marker->original_length - data_length; 946 } 947 /* Reset to initial state for next marker */ 948 marker->cur_marker = NULL; 949 950 /* Process the marker if interesting; else just make a generic trace msg */ 951 switch (cinfo->unread_marker) { 952 case M_APP0: 953 examine_app0(cinfo, data, data_length, length); 954 break; 955 case M_APP14: 956 examine_app14(cinfo, data, data_length, length); 957 break; 958 default: 959 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, 960 (int) (data_length + length)); 961 break; 962 } 963 964 /* skip any remaining data -- could be lots */ 965 INPUT_SYNC(cinfo); /* do before skip_input_data */ 966 if (length > 0) 967 (*cinfo->src->skip_input_data) (cinfo, (long) length); 968 969 return TRUE; 970 } 971 972 #endif /* SAVE_MARKERS_SUPPORTED */ 973 974 975 METHODDEF(boolean) 976 skip_variable (j_decompress_ptr cinfo) 977 /* Skip over an unknown or uninteresting variable-length marker */ 978 { 979 INT32 length; 980 INPUT_VARS(cinfo); 981 982 INPUT_2BYTES(cinfo, length, return FALSE); 983 length -= 2; 984 985 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, (int) length); 986 987 INPUT_SYNC(cinfo); /* do before skip_input_data */ 988 if (length > 0) 989 (*cinfo->src->skip_input_data) (cinfo, (long) length); 990 991 return TRUE; 992 } 993 994 995 /* 996 * Find the next JPEG marker, save it in cinfo->unread_marker. 997 * Returns FALSE if had to suspend before reaching a marker; 998 * in that case cinfo->unread_marker is unchanged. 999 * 1000 * Note that the result might not be a valid marker code, 1001 * but it will never be 0 or FF. 1002 */ 1003 1004 LOCAL(boolean) 1005 next_marker (j_decompress_ptr cinfo) 1006 { 1007 int c; 1008 INPUT_VARS(cinfo); 1009 1010 for (;;) { 1011 INPUT_BYTE(cinfo, c, return FALSE); 1012 /* Skip any non-FF bytes. 1013 * This may look a bit inefficient, but it will not occur in a valid file. 1014 * We sync after each discarded byte so that a suspending data source 1015 * can discard the byte from its buffer. 1016 */ 1017 while (c != 0xFF) { 1018 cinfo->marker->discarded_bytes++; 1019 INPUT_SYNC(cinfo); 1020 INPUT_BYTE(cinfo, c, return FALSE); 1021 } 1022 /* This loop swallows any duplicate FF bytes. Extra FFs are legal as 1023 * pad bytes, so don't count them in discarded_bytes. We assume there 1024 * will not be so many consecutive FF bytes as to overflow a suspending 1025 * data source's input buffer. 1026 */ 1027 do { 1028 INPUT_BYTE(cinfo, c, return FALSE); 1029 } while (c == 0xFF); 1030 if (c != 0) 1031 break; /* found a valid marker, exit loop */ 1032 /* Reach here if we found a stuffed-zero data sequence (FF/00). 1033 * Discard it and loop back to try again. 1034 */ 1035 cinfo->marker->discarded_bytes += 2; 1036 INPUT_SYNC(cinfo); 1037 } 1038 1039 if (cinfo->marker->discarded_bytes != 0) { 1040 WARNMS2(cinfo, JWRN_EXTRANEOUS_DATA, cinfo->marker->discarded_bytes, c); 1041 cinfo->marker->discarded_bytes = 0; 1042 } 1043 1044 cinfo->unread_marker = c; 1045 1046 INPUT_SYNC(cinfo); 1047 return TRUE; 1048 } 1049 1050 1051 LOCAL(boolean) 1052 first_marker (j_decompress_ptr cinfo) 1053 /* Like next_marker, but used to obtain the initial SOI marker. */ 1054 /* For this marker, we do not allow preceding garbage or fill; otherwise, 1055 * we might well scan an entire input file before realizing it ain't JPEG. 1056 * If an application wants to process non-JFIF files, it must seek to the 1057 * SOI before calling the JPEG library. 1058 */ 1059 { 1060 int c, c2; 1061 INPUT_VARS(cinfo); 1062 1063 INPUT_BYTE(cinfo, c, return FALSE); 1064 INPUT_BYTE(cinfo, c2, return FALSE); 1065 if (c != 0xFF || c2 != (int) M_SOI) 1066 ERREXIT2(cinfo, JERR_NO_SOI, c, c2); 1067 1068 cinfo->unread_marker = c2; 1069 1070 INPUT_SYNC(cinfo); 1071 return TRUE; 1072 } 1073 1074 1075 /* 1076 * Read markers until SOS or EOI. 1077 * 1078 * Returns same codes as are defined for jpeg_consume_input: 1079 * JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI. 1080 * 1081 * Note: This function may return a pseudo SOS marker (with zero 1082 * component number) for treat by input controller's consume_input. 1083 * consume_input itself should filter out (skip) the pseudo marker 1084 * after processing for the caller. 1085 */ 1086 1087 METHODDEF(int) 1088 read_markers (j_decompress_ptr cinfo) 1089 { 1090 /* Outer loop repeats once for each marker. */ 1091 for (;;) { 1092 /* Collect the marker proper, unless we already did. */ 1093 /* NB: first_marker() enforces the requirement that SOI appear first. */ 1094 if (cinfo->unread_marker == 0) { 1095 if (! cinfo->marker->saw_SOI) { 1096 if (! first_marker(cinfo)) 1097 return JPEG_SUSPENDED; 1098 } else { 1099 if (! next_marker(cinfo)) 1100 return JPEG_SUSPENDED; 1101 } 1102 } 1103 /* At this point cinfo->unread_marker contains the marker code and the 1104 * input point is just past the marker proper, but before any parameters. 1105 * A suspension will cause us to return with this state still true. 1106 */ 1107 switch (cinfo->unread_marker) { 1108 case M_SOI: 1109 if (! get_soi(cinfo)) 1110 return JPEG_SUSPENDED; 1111 break; 1112 1113 case M_SOF0: /* Baseline */ 1114 if (! get_sof(cinfo, TRUE, FALSE, FALSE)) 1115 return JPEG_SUSPENDED; 1116 break; 1117 1118 case M_SOF1: /* Extended sequential, Huffman */ 1119 if (! get_sof(cinfo, FALSE, FALSE, FALSE)) 1120 return JPEG_SUSPENDED; 1121 break; 1122 1123 case M_SOF2: /* Progressive, Huffman */ 1124 if (! get_sof(cinfo, FALSE, TRUE, FALSE)) 1125 return JPEG_SUSPENDED; 1126 break; 1127 1128 case M_SOF9: /* Extended sequential, arithmetic */ 1129 if (! get_sof(cinfo, FALSE, FALSE, TRUE)) 1130 return JPEG_SUSPENDED; 1131 break; 1132 1133 case M_SOF10: /* Progressive, arithmetic */ 1134 if (! get_sof(cinfo, FALSE, TRUE, TRUE)) 1135 return JPEG_SUSPENDED; 1136 break; 1137 1138 /* Currently unsupported SOFn types */ 1139 case M_SOF3: /* Lossless, Huffman */ 1140 case M_SOF5: /* Differential sequential, Huffman */ 1141 case M_SOF6: /* Differential progressive, Huffman */ 1142 case M_SOF7: /* Differential lossless, Huffman */ 1143 case M_JPG: /* Reserved for JPEG extensions */ 1144 case M_SOF11: /* Lossless, arithmetic */ 1145 case M_SOF13: /* Differential sequential, arithmetic */ 1146 case M_SOF14: /* Differential progressive, arithmetic */ 1147 case M_SOF15: /* Differential lossless, arithmetic */ 1148 ERREXIT1(cinfo, JERR_SOF_UNSUPPORTED, cinfo->unread_marker); 1149 break; 1150 1151 case M_SOS: 1152 if (! get_sos(cinfo)) 1153 return JPEG_SUSPENDED; 1154 cinfo->unread_marker = 0; /* processed the marker */ 1155 return JPEG_REACHED_SOS; 1156 1157 case M_EOI: 1158 TRACEMS(cinfo, 1, JTRC_EOI); 1159 cinfo->unread_marker = 0; /* processed the marker */ 1160 return JPEG_REACHED_EOI; 1161 1162 case M_DAC: 1163 if (! get_dac(cinfo)) 1164 return JPEG_SUSPENDED; 1165 break; 1166 1167 case M_DHT: 1168 if (! get_dht(cinfo)) 1169 return JPEG_SUSPENDED; 1170 break; 1171 1172 case M_DQT: 1173 if (! get_dqt(cinfo)) 1174 return JPEG_SUSPENDED; 1175 break; 1176 1177 case M_DRI: 1178 if (! get_dri(cinfo)) 1179 return JPEG_SUSPENDED; 1180 break; 1181 1182 case M_JPG8: 1183 if (! get_lse(cinfo)) 1184 return JPEG_SUSPENDED; 1185 break; 1186 1187 case M_APP0: 1188 case M_APP1: 1189 case M_APP2: 1190 case M_APP3: 1191 case M_APP4: 1192 case M_APP5: 1193 case M_APP6: 1194 case M_APP7: 1195 case M_APP8: 1196 case M_APP9: 1197 case M_APP10: 1198 case M_APP11: 1199 case M_APP12: 1200 case M_APP13: 1201 case M_APP14: 1202 case M_APP15: 1203 if (! (*((my_marker_ptr) cinfo->marker)->process_APPn[ 1204 cinfo->unread_marker - (int) M_APP0]) (cinfo)) 1205 return JPEG_SUSPENDED; 1206 break; 1207 1208 case M_COM: 1209 if (! (*((my_marker_ptr) cinfo->marker)->process_COM) (cinfo)) 1210 return JPEG_SUSPENDED; 1211 break; 1212 1213 case M_RST0: /* these are all parameterless */ 1214 case M_RST1: 1215 case M_RST2: 1216 case M_RST3: 1217 case M_RST4: 1218 case M_RST5: 1219 case M_RST6: 1220 case M_RST7: 1221 case M_TEM: 1222 TRACEMS1(cinfo, 1, JTRC_PARMLESS_MARKER, cinfo->unread_marker); 1223 break; 1224 1225 case M_DNL: /* Ignore DNL ... perhaps the wrong thing */ 1226 if (! skip_variable(cinfo)) 1227 return JPEG_SUSPENDED; 1228 break; 1229 1230 default: /* must be DHP, EXP, JPGn, or RESn */ 1231 /* For now, we treat the reserved markers as fatal errors since they are 1232 * likely to be used to signal incompatible JPEG Part 3 extensions. 1233 * Once the JPEG 3 version-number marker is well defined, this code 1234 * ought to change! 1235 */ 1236 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker); 1237 break; 1238 } 1239 /* Successfully processed marker, so reset state variable */ 1240 cinfo->unread_marker = 0; 1241 } /* end loop */ 1242 } 1243 1244 1245 /* 1246 * Read a restart marker, which is expected to appear next in the datastream; 1247 * if the marker is not there, take appropriate recovery action. 1248 * Returns FALSE if suspension is required. 1249 * 1250 * This is called by the entropy decoder after it has read an appropriate 1251 * number of MCUs. cinfo->unread_marker may be nonzero if the entropy decoder 1252 * has already read a marker from the data source. Under normal conditions 1253 * cinfo->unread_marker will be reset to 0 before returning; if not reset, 1254 * it holds a marker which the decoder will be unable to read past. 1255 */ 1256 1257 METHODDEF(boolean) 1258 read_restart_marker (j_decompress_ptr cinfo) 1259 { 1260 /* Obtain a marker unless we already did. */ 1261 /* Note that next_marker will complain if it skips any data. */ 1262 if (cinfo->unread_marker == 0) { 1263 if (! next_marker(cinfo)) 1264 return FALSE; 1265 } 1266 1267 if (cinfo->unread_marker == 1268 ((int) M_RST0 + cinfo->marker->next_restart_num)) { 1269 /* Normal case --- swallow the marker and let entropy decoder continue */ 1270 TRACEMS1(cinfo, 3, JTRC_RST, cinfo->marker->next_restart_num); 1271 cinfo->unread_marker = 0; 1272 } else { 1273 /* Uh-oh, the restart markers have been messed up. */ 1274 /* Let the data source manager determine how to resync. */ 1275 if (! (*cinfo->src->resync_to_restart) (cinfo, 1276 cinfo->marker->next_restart_num)) 1277 return FALSE; 1278 } 1279 1280 /* Update next-restart state */ 1281 cinfo->marker->next_restart_num = (cinfo->marker->next_restart_num + 1) & 7; 1282 1283 return TRUE; 1284 } 1285 1286 1287 /* 1288 * This is the default resync_to_restart method for data source managers 1289 * to use if they don't have any better approach. Some data source managers 1290 * may be able to back up, or may have additional knowledge about the data 1291 * which permits a more intelligent recovery strategy; such managers would 1292 * presumably supply their own resync method. 1293 * 1294 * read_restart_marker calls resync_to_restart if it finds a marker other than 1295 * the restart marker it was expecting. (This code is *not* used unless 1296 * a nonzero restart interval has been declared.) cinfo->unread_marker is 1297 * the marker code actually found (might be anything, except 0 or FF). 1298 * The desired restart marker number (0..7) is passed as a parameter. 1299 * This routine is supposed to apply whatever error recovery strategy seems 1300 * appropriate in order to position the input stream to the next data segment. 1301 * Note that cinfo->unread_marker is treated as a marker appearing before 1302 * the current data-source input point; usually it should be reset to zero 1303 * before returning. 1304 * Returns FALSE if suspension is required. 1305 * 1306 * This implementation is substantially constrained by wanting to treat the 1307 * input as a data stream; this means we can't back up. Therefore, we have 1308 * only the following actions to work with: 1309 * 1. Simply discard the marker and let the entropy decoder resume at next 1310 * byte of file. 1311 * 2. Read forward until we find another marker, discarding intervening 1312 * data. (In theory we could look ahead within the current bufferload, 1313 * without having to discard data if we don't find the desired marker. 1314 * This idea is not implemented here, in part because it makes behavior 1315 * dependent on buffer size and chance buffer-boundary positions.) 1316 * 3. Leave the marker unread (by failing to zero cinfo->unread_marker). 1317 * This will cause the entropy decoder to process an empty data segment, 1318 * inserting dummy zeroes, and then we will reprocess the marker. 1319 * 1320 * #2 is appropriate if we think the desired marker lies ahead, while #3 is 1321 * appropriate if the found marker is a future restart marker (indicating 1322 * that we have missed the desired restart marker, probably because it got 1323 * corrupted). 1324 * We apply #2 or #3 if the found marker is a restart marker no more than 1325 * two counts behind or ahead of the expected one. We also apply #2 if the 1326 * found marker is not a legal JPEG marker code (it's certainly bogus data). 1327 * If the found marker is a restart marker more than 2 counts away, we do #1 1328 * (too much risk that the marker is erroneous; with luck we will be able to 1329 * resync at some future point). 1330 * For any valid non-restart JPEG marker, we apply #3. This keeps us from 1331 * overrunning the end of a scan. An implementation limited to single-scan 1332 * files might find it better to apply #2 for markers other than EOI, since 1333 * any other marker would have to be bogus data in that case. 1334 */ 1335 1336 GLOBAL(boolean) 1337 jpeg_resync_to_restart (j_decompress_ptr cinfo, int desired) 1338 { 1339 int marker = cinfo->unread_marker; 1340 int action = 1; 1341 1342 /* Always put up a warning. */ 1343 WARNMS2(cinfo, JWRN_MUST_RESYNC, marker, desired); 1344 1345 /* Outer loop handles repeated decision after scanning forward. */ 1346 for (;;) { 1347 if (marker < (int) M_SOF0) 1348 action = 2; /* invalid marker */ 1349 else if (marker < (int) M_RST0 || marker > (int) M_RST7) 1350 action = 3; /* valid non-restart marker */ 1351 else { 1352 if (marker == ((int) M_RST0 + ((desired+1) & 7)) || 1353 marker == ((int) M_RST0 + ((desired+2) & 7))) 1354 action = 3; /* one of the next two expected restarts */ 1355 else if (marker == ((int) M_RST0 + ((desired-1) & 7)) || 1356 marker == ((int) M_RST0 + ((desired-2) & 7))) 1357 action = 2; /* a prior restart, so advance */ 1358 else 1359 action = 1; /* desired restart or too far away */ 1360 } 1361 TRACEMS2(cinfo, 4, JTRC_RECOVERY_ACTION, marker, action); 1362 switch (action) { 1363 case 1: 1364 /* Discard marker and let entropy decoder resume processing. */ 1365 cinfo->unread_marker = 0; 1366 return TRUE; 1367 case 2: 1368 /* Scan to the next marker, and repeat the decision loop. */ 1369 if (! next_marker(cinfo)) 1370 return FALSE; 1371 marker = cinfo->unread_marker; 1372 break; 1373 case 3: 1374 /* Return without advancing past this marker. */ 1375 /* Entropy decoder will be forced to process an empty segment. */ 1376 return TRUE; 1377 } 1378 } /* end loop */ 1379 } 1380 1381 1382 /* 1383 * Reset marker processing state to begin a fresh datastream. 1384 */ 1385 1386 METHODDEF(void) 1387 reset_marker_reader (j_decompress_ptr cinfo) 1388 { 1389 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 1390 1391 cinfo->comp_info = NULL; /* until allocated by get_sof */ 1392 cinfo->input_scan_number = 0; /* no SOS seen yet */ 1393 cinfo->unread_marker = 0; /* no pending marker */ 1394 marker->pub.saw_SOI = FALSE; /* set internal state too */ 1395 marker->pub.saw_SOF = FALSE; 1396 marker->pub.discarded_bytes = 0; 1397 marker->cur_marker = NULL; 1398 } 1399 1400 1401 /* 1402 * Initialize the marker reader module. 1403 * This is called only once, when the decompression object is created. 1404 */ 1405 1406 GLOBAL(void) 1407 jinit_marker_reader (j_decompress_ptr cinfo) 1408 { 1409 my_marker_ptr marker; 1410 int i; 1411 1412 /* Create subobject in permanent pool */ 1413 marker = (my_marker_ptr) 1414 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT, 1415 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
