1 /* 2 * jdmarker.c 3 * 4 * Copyright (C) 1991-1998, Thomas G. Lane. 5 * This file is part of the Independent JPEG Group's software. 6 * For conditions of distribution and use, see the accompanying README file. 7 * 8 * This file contains routines to decode JPEG datastream markers. 9 * Most of the complexity arises from our desire to support input 10 * suspension: if not all of the data for a marker is available, 11 * we must exit back to the application. On resumption, we reprocess 12 * the marker. 13 */ 14 15 #define JPEG_INTERNALS 16 #include "jinclude.h" 17 #include "jpeglib.h" 18 19 20 typedef enum { /* JPEG marker codes */ 21 M_SOF0 = 0xc0, 22 M_SOF1 = 0xc1, 23 M_SOF2 = 0xc2, 24 M_SOF3 = 0xc3, 25 26 M_SOF5 = 0xc5, 27 M_SOF6 = 0xc6, 28 M_SOF7 = 0xc7, 29 30 M_JPG = 0xc8, 31 M_SOF9 = 0xc9, 32 M_SOF10 = 0xca, 33 M_SOF11 = 0xcb, 34 35 M_SOF13 = 0xcd, 36 M_SOF14 = 0xce, 37 M_SOF15 = 0xcf, 38 39 M_DHT = 0xc4, 40 41 M_DAC = 0xcc, 42 43 M_RST0 = 0xd0, 44 M_RST1 = 0xd1, 45 M_RST2 = 0xd2, 46 M_RST3 = 0xd3, 47 M_RST4 = 0xd4, 48 M_RST5 = 0xd5, 49 M_RST6 = 0xd6, 50 M_RST7 = 0xd7, 51 52 M_SOI = 0xd8, 53 M_EOI = 0xd9, 54 M_SOS = 0xda, 55 M_DQT = 0xdb, 56 M_DNL = 0xdc, 57 M_DRI = 0xdd, 58 M_DHP = 0xde, 59 M_EXP = 0xdf, 60 61 M_APP0 = 0xe0, 62 M_APP1 = 0xe1, 63 M_APP2 = 0xe2, 64 M_APP3 = 0xe3, 65 M_APP4 = 0xe4, 66 M_APP5 = 0xe5, 67 M_APP6 = 0xe6, 68 M_APP7 = 0xe7, 69 M_APP8 = 0xe8, 70 M_APP9 = 0xe9, 71 M_APP10 = 0xea, 72 M_APP11 = 0xeb, 73 M_APP12 = 0xec, 74 M_APP13 = 0xed, 75 M_APP14 = 0xee, 76 M_APP15 = 0xef, 77 78 M_JPG0 = 0xf0, 79 M_JPG13 = 0xfd, 80 M_COM = 0xfe, 81 82 M_TEM = 0x01, 83 84 M_ERROR = 0x100 85 } JPEG_MARKER; 86 87 88 /* Private state */ 89 90 typedef struct { 91 struct jpeg_marker_reader pub; /* public fields */ 92 93 /* Application-overridable marker processing methods */ 94 jpeg_marker_parser_method process_COM; 95 jpeg_marker_parser_method process_APPn[16]; 96 97 /* Limit on marker data length to save for each marker type */ 98 unsigned int length_limit_COM; 99 unsigned int length_limit_APPn[16]; 100 101 /* Status of COM/APPn marker saving */ 102 jpeg_saved_marker_ptr cur_marker; /* NULL if not processing a marker */ 103 unsigned int bytes_read; /* data bytes read so far in marker */ 104 /* Note: cur_marker is not linked into marker_list until it's all read. */ 105 } my_marker_reader; 106 107 typedef my_marker_reader * my_marker_ptr; 108 109 110 /* 111 * Macros for fetching data from the data source module. 112 * 113 * At all times, cinfo->src->next_input_byte and ->bytes_in_buffer reflect 114 * the current restart point; we update them only when we have reached a 115 * suitable place to restart if a suspension occurs. 116 */ 117 118 /* Declare and initialize local copies of input pointer/count */ 119 #define INPUT_VARS(cinfo) \ 120 struct jpeg_source_mgr * datasrc = (cinfo)->src; \ 121 const JOCTET * next_input_byte = datasrc->next_input_byte; \ 122 size_t bytes_in_buffer = datasrc->bytes_in_buffer 123 124 /* Unload the local copies --- do this only at a restart boundary */ 125 #define INPUT_SYNC(cinfo) \ 126 ( datasrc->next_input_byte = next_input_byte, \ 127 datasrc->bytes_in_buffer = bytes_in_buffer ) 128 129 /* Reload the local copies --- used only in MAKE_BYTE_AVAIL */ 130 #define INPUT_RELOAD(cinfo) \ 131 ( next_input_byte = datasrc->next_input_byte, \ 132 bytes_in_buffer = datasrc->bytes_in_buffer ) 133 134 /* Internal macro for INPUT_BYTE and INPUT_2BYTES: make a byte available. 135 * Note we do *not* do INPUT_SYNC before calling fill_input_buffer, 136 * but we must reload the local copies after a successful fill. 137 */ 138 #define MAKE_BYTE_AVAIL(cinfo,action) \ 139 if (bytes_in_buffer == 0) { \ 140 if (! (*datasrc->fill_input_buffer) (cinfo)) \ 141 { action; } \ 142 INPUT_RELOAD(cinfo); \ 143 } 144 145 /* Read a byte into variable V. 146 * If must suspend, take the specified action (typically "return FALSE"). 147 */ 148 #define INPUT_BYTE(cinfo,V,action) \ 149 MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \ 150 bytes_in_buffer--; \ 151 V = GETJOCTET(*next_input_byte++); ) 152 153 /* As above, but read two bytes interpreted as an unsigned 16-bit integer. 154 * V should be declared unsigned int or perhaps INT32. 155 */ 156 #define INPUT_2BYTES(cinfo,V,action) \ 157 MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \ 158 bytes_in_buffer--; \ 159 V = ((unsigned int) GETJOCTET(*next_input_byte++)) << 8; \ 160 MAKE_BYTE_AVAIL(cinfo,action); \ 161 bytes_in_buffer--; \ 162 V += GETJOCTET(*next_input_byte++); ) 163 164 165 /* 166 * Routines to process JPEG markers. 167 * 168 * Entry condition: JPEG marker itself has been read and its code saved 169 * in cinfo->unread_marker; input restart point is just after the marker. 170 * 171 * Exit: if return TRUE, have read and processed any parameters, and have 172 * updated the restart point to point after the parameters. 173 * If return FALSE, was forced to suspend before reaching end of 174 * marker parameters; restart point has not been moved. Same routine 175 * will be called again after application supplies more input data. 176 * 177 * This approach to suspension assumes that all of a marker's parameters 178 * can fit into a single input bufferload. This should hold for "normal" 179 * markers. Some COM/APPn markers might have large parameter segments 180 * that might not fit. If we are simply dropping such a marker, we use 181 * skip_input_data to get past it, and thereby put the problem on the 182 * source manager's shoulders. If we are saving the marker's contents 183 * into memory, we use a slightly different convention: when forced to 184 * suspend, the marker processor updates the restart point to the end of 185 * what it's consumed (ie, the end of the buffer) before returning FALSE. 186 * On resumption, cinfo->unread_marker still contains the marker code, 187 * but the data source will point to the next chunk of marker data. 188 * The marker processor must retain internal state to deal with this. 189 * 190 * Note that we don't bother to avoid duplicate trace messages if a 191 * suspension occurs within marker parameters. Other side effects 192 * require more care. 193 */ 194 195 196 LOCAL(boolean) 197 get_soi (j_decompress_ptr cinfo) 198 /* Process an SOI marker */ 199 { 200 int i; 201 202 TRACEMS(cinfo, 1, JTRC_SOI); 203 204 if (cinfo->marker->saw_SOI) 205 ERREXIT(cinfo, JERR_SOI_DUPLICATE); 206 207 /* Reset all parameters that are defined to be reset by SOI */ 208 209 for (i = 0; i < NUM_ARITH_TBLS; i++) { 210 cinfo->arith_dc_L[i] = 0; 211 cinfo->arith_dc_U[i] = 1; 212 cinfo->arith_ac_K[i] = 5; 213 } 214 cinfo->restart_interval = 0; 215 216 /* Set initial assumptions for colorspace etc */ 217 218 cinfo->jpeg_color_space = JCS_UNKNOWN; 219 cinfo->CCIR601_sampling = FALSE; /* Assume non-CCIR sampling??? */ 220 221 cinfo->saw_JFIF_marker = FALSE; 222 cinfo->JFIF_major_version = 1; /* set default JFIF APP0 values */ 223 cinfo->JFIF_minor_version = 1; 224 cinfo->density_unit = 0; 225 cinfo->X_density = 1; 226 cinfo->Y_density = 1; 227 cinfo->saw_Adobe_marker = FALSE; 228 cinfo->Adobe_transform = 0; 229 230 cinfo->marker->saw_SOI = TRUE; 231 232 return TRUE; 233 } 234 235 236 LOCAL(boolean) 237 get_sof (j_decompress_ptr cinfo, boolean is_prog, boolean is_arith) 238 /* Process a SOFn marker */ 239 { 240 INT32 length; 241 int c, ci; 242 jpeg_component_info * compptr; 243 /* LiuSunliang added 20111209 */ 244 JDIMENSION image_width, image_height; 245 INPUT_VARS(cinfo); 246 247 cinfo->progressive_mode = is_prog; 248 cinfo->arith_code = is_arith; 249 250 INPUT_2BYTES(cinfo, length, return FALSE); 251 252 INPUT_BYTE(cinfo, cinfo->data_precision, return FALSE); 253 INPUT_2BYTES(cinfo, image_height, return FALSE); 254 INPUT_2BYTES(cinfo, image_width, return FALSE); 255 INPUT_BYTE(cinfo, cinfo->num_components, return FALSE); 256 257 if (image_width <= JPEG_MAX_DIMENSION) 258 cinfo->image_width = image_width; 259 260 if (image_height <= JPEG_MAX_DIMENSION) 261 cinfo->image_height = image_height; 262 263 length -= 8; 264 265 TRACEMS4(cinfo, 1, JTRC_SOF, cinfo->unread_marker, 266 (int) cinfo->image_width, (int) cinfo->image_height, 267 cinfo->num_components); 268 269 if (cinfo->marker->saw_SOF) 270 ERREXIT(cinfo, JERR_SOF_DUPLICATE); 271 272 /* We don't support files in which the image height is initially specified */ 273 /* as 0 and is later redefined by DNL. As long as we have to check that, */ 274 /* might as well have a general sanity check. */ 275 if (cinfo->image_height <= 0 || cinfo->image_width <= 0 276 || cinfo->num_components <= 0) 277 ERREXIT(cinfo, JERR_EMPTY_IMAGE); 278 279 if (length != (cinfo->num_components * 3)) 280 ERREXIT(cinfo, JERR_BAD_LENGTH); 281 282 if (cinfo->comp_info == NULL) /* do only once, even if suspend */ 283 cinfo->comp_info = (jpeg_component_info *) (*cinfo->mem->alloc_small) 284 ((j_common_ptr) cinfo, JPOOL_IMAGE, 285 cinfo->num_components * SIZEOF(jpeg_component_info)); 286 287 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 288 ci++, compptr++) { 289 compptr->component_index = ci; 290 INPUT_BYTE(cinfo, compptr->component_id, return FALSE); 291 /* XYQ 2008-03-25: Adobe CMYK JPEG has serious flaw: the K channel has same component id as C channel */ 292 { 293 int i; 294 for (i = 0; i < ci; i ++) 295 if (compptr->component_id == cinfo->comp_info[i].component_id) break; 296 if (i < ci) 297 /* Found the error! We replace the id with something unlikely used elsewhere */ 298 compptr->component_id += 0xf0; 299 } 300 /* end of modification */ 301 INPUT_BYTE(cinfo, c, return FALSE); 302 compptr->h_samp_factor = (c >> 4) & 15; 303 compptr->v_samp_factor = (c ) & 15; 304 INPUT_BYTE(cinfo, compptr->quant_tbl_no, return FALSE); 305 306 TRACEMS4(cinfo, 1, JTRC_SOF_COMPONENT, 307 compptr->component_id, compptr->h_samp_factor, 308 compptr->v_samp_factor, compptr->quant_tbl_no); 309 } 310 311 cinfo->marker->saw_SOF = TRUE; 312 313 INPUT_SYNC(cinfo); 314 return TRUE; 315 } 316 317 318 LOCAL(boolean) 319 get_sos (j_decompress_ptr cinfo) 320 /* Process a SOS marker */ 321 { 322 INT32 length; 323 int i, ci, n, c, cc; 324 jpeg_component_info * compptr; 325 INPUT_VARS(cinfo); 326 327 if (! cinfo->marker->saw_SOF) 328 ERREXIT(cinfo, JERR_SOS_NO_SOF); 329 330 INPUT_2BYTES(cinfo, length, return FALSE); 331 332 INPUT_BYTE(cinfo, n, return FALSE); /* Number of components */ 333 334 TRACEMS1(cinfo, 1, JTRC_SOS, n); 335 336 if (length != (n * 2 + 6) || n < 1 || n > MAX_COMPS_IN_SCAN) 337 ERREXIT(cinfo, JERR_BAD_LENGTH); 338 339 cinfo->comps_in_scan = n; 340 341 /* Collect the component-spec parameters */ 342 343 for (i = 0; i < n; i++) { 344 INPUT_BYTE(cinfo, cc, return FALSE); 345 INPUT_BYTE(cinfo, c, return FALSE); 346 347 /* XYQ 2008-03-25: Adobe CMYK JPEG has serious flaw: the K channel has same component id as C channel */ 348 { 349 int j; 350 for (j = 0; j < i; j ++) 351 if (cc == cinfo->cur_comp_info[j]->component_id) break; 352 if (j < i) 353 /* found the error! */ 354 cc += 0xf0; 355 } 356 /* end of modification */ 357 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 358 ci++, compptr++) { 359 if (cc == compptr->component_id) 360 goto id_found; 361 } 362 363 ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc); 364 365 id_found: 366 367 cinfo->cur_comp_info[i] = compptr; 368 compptr->dc_tbl_no = (c >> 4) & 15; 369 compptr->ac_tbl_no = (c ) & 15; 370 371 TRACEMS3(cinfo, 1, JTRC_SOS_COMPONENT, cc, 372 compptr->dc_tbl_no, compptr->ac_tbl_no); 373 /* This CSi (cc) should differ from the previous CSi */ 374 for (ci = 0; ci < i; ci++) { 375 if (cinfo->cur_comp_info[ci] == compptr) 376 ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc); 377 } 378 } 379 380 /* Collect the additional scan parameters Ss, Se, Ah/Al. */ 381 INPUT_BYTE(cinfo, c, return FALSE); 382 cinfo->Ss = c; 383 INPUT_BYTE(cinfo, c, return FALSE); 384 cinfo->Se = c; 385 INPUT_BYTE(cinfo, c, return FALSE); 386 cinfo->Ah = (c >> 4) & 15; 387 cinfo->Al = (c ) & 15; 388 389 TRACEMS4(cinfo, 1, JTRC_SOS_PARAMS, cinfo->Ss, cinfo->Se, 390 cinfo->Ah, cinfo->Al); 391 392 /* Prepare to scan data & restart markers */ 393 cinfo->marker->next_restart_num = 0; 394 395 /* Count another SOS marker */ 396 cinfo->input_scan_number++; 397 398 INPUT_SYNC(cinfo); 399 return TRUE; 400 } 401 402 403 #ifdef D_ARITH_CODING_SUPPORTED 404 405 LOCAL(boolean) 406 get_dac (j_decompress_ptr cinfo) 407 /* Process a DAC marker */ 408 { 409 INT32 length; 410 int index, val; 411 INPUT_VARS(cinfo); 412 413 INPUT_2BYTES(cinfo, length, return FALSE); 414 length -= 2; 415 416 while (length > 0) { 417 INPUT_BYTE(cinfo, index, return FALSE); 418 INPUT_BYTE(cinfo, val, return FALSE); 419 420 length -= 2; 421 422 TRACEMS2(cinfo, 1, JTRC_DAC, index, val); 423 424 if (index < 0 || index >= (2*NUM_ARITH_TBLS)) 425 ERREXIT1(cinfo, JERR_DAC_INDEX, index); 426 427 if (index >= NUM_ARITH_TBLS) { /* define AC table */ 428 cinfo->arith_ac_K[index-NUM_ARITH_TBLS] = (UINT8) val; 429 } else { /* define DC table */ 430 cinfo->arith_dc_L[index] = (UINT8) (val & 0x0F); 431 cinfo->arith_dc_U[index] = (UINT8) (val >> 4); 432 if (cinfo->arith_dc_L[index] > cinfo->arith_dc_U[index]) 433 ERREXIT1(cinfo, JERR_DAC_VALUE, val); 434 } 435 } 436 437 if (length != 0) 438 ERREXIT(cinfo, JERR_BAD_LENGTH); 439 440 INPUT_SYNC(cinfo); 441 return TRUE; 442 } 443 444 #else /* ! D_ARITH_CODING_SUPPORTED */ 445 446 #define get_dac(cinfo) skip_variable(cinfo) 447 448 #endif /* D_ARITH_CODING_SUPPORTED */ 449 450 451 LOCAL(boolean) 452 get_dht (j_decompress_ptr cinfo) 453 /* Process a DHT marker */ 454 { 455 INT32 length; 456 UINT8 bits[17]; 457 UINT8 huffval[256]; 458 int i, index, count; 459 JHUFF_TBL **htblptr; 460 INPUT_VARS(cinfo); 461 462 INPUT_2BYTES(cinfo, length, return FALSE); 463 length -= 2; 464 465 while (length > 16) { 466 INPUT_BYTE(cinfo, index, return FALSE); 467 468 TRACEMS1(cinfo, 1, JTRC_DHT, index); 469 470 bits[0] = 0; 471 count = 0; 472 for (i = 1; i <= 16; i++) { 473 INPUT_BYTE(cinfo, bits[i], return FALSE); 474 count += bits[i]; 475 } 476 477 length -= 1 + 16; 478 479 TRACEMS8(cinfo, 2, JTRC_HUFFBITS, 480 bits[1], bits[2], bits[3], bits[4], 481 bits[5], bits[6], bits[7], bits[8]); 482 TRACEMS8(cinfo, 2, JTRC_HUFFBITS, 483 bits[9], bits[10], bits[11], bits[12], 484 bits[13], bits[14], bits[15], bits[16]); 485 486 /* Here we just do minimal validation of the counts to avoid walking 487 * off the end of our table space. jdhuff.c will check more carefully. 488 */ 489 if (count > 256 || ((INT32) count) > length) 490 ERREXIT(cinfo, JERR_BAD_HUFF_TABLE); 491 492 for (i = 0; i < count; i++) 493 INPUT_BYTE(cinfo, huffval[i], return FALSE); 494 495 length -= count; 496 497 if (index & 0x10) { /* AC table definition */ 498 index -= 0x10; 499 htblptr = &cinfo->ac_huff_tbl_ptrs[index]; 500 } else { /* DC table definition */ 501 htblptr = &cinfo->dc_huff_tbl_ptrs[index]; 502 } 503 504 if (index < 0 || index >= NUM_HUFF_TBLS) 505 ERREXIT1(cinfo, JERR_DHT_INDEX, index); 506 507 if (*htblptr == NULL) 508 *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo); 509 510 MEMCOPY((*htblptr)->bits, bits, SIZEOF((*htblptr)->bits)); 511 MEMCOPY((*htblptr)->huffval, huffval, SIZEOF((*htblptr)->huffval)); 512 } 513 514 if (length != 0) 515 ERREXIT(cinfo, JERR_BAD_LENGTH); 516 517 INPUT_SYNC(cinfo); 518 return TRUE; 519 } 520 521 522 LOCAL(boolean) 523 get_dqt (j_decompress_ptr cinfo) 524 /* Process a DQT marker */ 525 { 526 INT32 length; 527 int n, i, prec; 528 unsigned int tmp; 529 JQUANT_TBL *quant_ptr; 530 INPUT_VARS(cinfo); 531 532 INPUT_2BYTES(cinfo, length, return FALSE); 533 length -= 2; 534 535 while (length > 0) { 536 INPUT_BYTE(cinfo, n, return FALSE); 537 prec = n >> 4; 538 n &= 0x0F; 539 540 TRACEMS2(cinfo, 1, JTRC_DQT, n, prec); 541 542 if (n >= NUM_QUANT_TBLS) 543 ERREXIT1(cinfo, JERR_DQT_INDEX, n); 544 545 if (cinfo->quant_tbl_ptrs[n] == NULL) 546 cinfo->quant_tbl_ptrs[n] = jpeg_alloc_quant_table((j_common_ptr) cinfo); 547 quant_ptr = cinfo->quant_tbl_ptrs[n]; 548 549 for (i = 0; i < DCTSIZE2; i++) { 550 if (prec) 551 INPUT_2BYTES(cinfo, tmp, return FALSE); 552 else 553 INPUT_BYTE(cinfo, tmp, return FALSE); 554 /* We convert the zigzag-order table to natural array order. */ 555 quant_ptr->quantval[jpeg_natural_order[i]] = (UINT16) tmp; 556 } 557 558 if (cinfo->err->trace_level >= 2) { 559 for (i = 0; i < DCTSIZE2; i += 8) { 560 TRACEMS8(cinfo, 2, JTRC_QUANTVALS, 561 quant_ptr->quantval[i], quant_ptr->quantval[i+1], 562 quant_ptr->quantval[i+2], quant_ptr->quantval[i+3], 563 quant_ptr->quantval[i+4], quant_ptr->quantval[i+5], 564 quant_ptr->quantval[i+6], quant_ptr->quantval[i+7]); 565 } 566 } 567 568 length -= DCTSIZE2+1; 569 if (prec) length -= DCTSIZE2; 570 } 571 572 if (length != 0) 573 ERREXIT(cinfo, JERR_BAD_LENGTH); 574 575 INPUT_SYNC(cinfo); 576 return TRUE; 577 } 578 579 580 LOCAL(boolean) 581 get_dri (j_decompress_ptr cinfo) 582 /* Process a DRI marker */ 583 { 584 INT32 length; 585 unsigned int tmp; 586 INPUT_VARS(cinfo); 587 588 INPUT_2BYTES(cinfo, length, return FALSE); 589 590 if (length != 4) 591 ERREXIT(cinfo, JERR_BAD_LENGTH); 592 593 INPUT_2BYTES(cinfo, tmp, return FALSE); 594 595 TRACEMS1(cinfo, 1, JTRC_DRI, tmp); 596 597 cinfo->restart_interval = tmp; 598 599 INPUT_SYNC(cinfo); 600 return TRUE; 601 } 602 603 604 /* 605 * Routines for processing APPn and COM markers. 606 * These are either saved in memory or discarded, per application request. 607 * APP0 and APP14 are specially checked to see if they are 608 * JFIF and Adobe markers, respectively. 609 */ 610 611 #define APP0_DATA_LEN 14 /* Length of interesting data in APP0 */ 612 #define APP14_DATA_LEN 12 /* Length of interesting data in APP14 */ 613 #define APPN_DATA_LEN 14 /* Must be the largest of the above!! */ 614 615 616 LOCAL(void) 617 examine_app0 (j_decompress_ptr cinfo, JOCTET FAR * data, 618 unsigned int datalen, INT32 remaining) 619 /* Examine first few bytes from an APP0. 620 * Take appropriate action if it is a JFIF marker. 621 * datalen is # of bytes at data[], remaining is length of rest of marker data. 622 */ 623 { 624 INT32 totallen = (INT32) datalen + remaining; 625 626 if (datalen >= APP0_DATA_LEN && 627 GETJOCTET(data[0]) == 0x4A && 628 GETJOCTET(data[1]) == 0x46 && 629 GETJOCTET(data[2]) == 0x49 && 630 GETJOCTET(data[3]) == 0x46 && 631 GETJOCTET(data[4]) == 0) { 632 /* Found JFIF APP0 marker: save info */ 633 cinfo->saw_JFIF_marker = TRUE; 634 cinfo->JFIF_major_version = GETJOCTET(data[5]); 635 cinfo->JFIF_minor_version = GETJOCTET(data[6]); 636 cinfo->density_unit = GETJOCTET(data[7]); 637 cinfo->X_density = (GETJOCTET(data[8]) << 8) + GETJOCTET(data[9]); 638 cinfo->Y_density = (GETJOCTET(data[10]) << 8) + GETJOCTET(data[11]); 639 /* Check version. 640 * Major version must be 1, anything else signals an incompatible change. 641 * (We used to treat this as an error, but now it's a nonfatal warning, 642 * because some bozo at Hijaak couldn't read the spec.) 643 * Minor version should be 0..2, but process anyway if newer. 644 */ 645 if (cinfo->JFIF_major_version != 1) 646 WARNMS2(cinfo, JWRN_JFIF_MAJOR, 647 cinfo->JFIF_major_version, cinfo->JFIF_minor_version); 648 /* Generate trace messages */ 649 TRACEMS5(cinfo, 1, JTRC_JFIF, 650 cinfo->JFIF_major_version, cinfo->JFIF_minor_version, 651 cinfo->X_density, cinfo->Y_density, cinfo->density_unit); 652 /* Validate thumbnail dimensions and issue appropriate messages */ 653 if (GETJOCTET(data[12]) | GETJOCTET(data[13])) 654 TRACEMS2(cinfo, 1, JTRC_JFIF_THUMBNAIL, 655 GETJOCTET(data[12]), GETJOCTET(data[13])); 656 totallen -= APP0_DATA_LEN; 657 if (totallen != 658 ((INT32)GETJOCTET(data[12]) * (INT32)GETJOCTET(data[13]) * (INT32) 3)) 659 TRACEMS1(cinfo, 1, JTRC_JFIF_BADTHUMBNAILSIZE, (int) totallen); 660 } else if (datalen >= 6 && 661 GETJOCTET(data[0]) == 0x4A && 662 GETJOCTET(data[1]) == 0x46 && 663 GETJOCTET(data[2]) == 0x58 && 664 GETJOCTET(data[3]) == 0x58 && 665 GETJOCTET(data[4]) == 0) { 666 /* Found JFIF "JFXX" extension APP0 marker */ 667 /* The library doesn't actually do anything with these, 668 * but we try to produce a helpful trace message. 669 */ 670 switch (GETJOCTET(data[5])) { 671 case 0x10: 672 TRACEMS1(cinfo, 1, JTRC_THUMB_JPEG, (int) totallen); 673 break; 674 case 0x11: 675 TRACEMS1(cinfo, 1, JTRC_THUMB_PALETTE, (int) totallen); 676 break; 677 case 0x13: 678 TRACEMS1(cinfo, 1, JTRC_THUMB_RGB, (int) totallen); 679 break; 680 default: 681 TRACEMS2(cinfo, 1, JTRC_JFIF_EXTENSION, 682 GETJOCTET(data[5]), (int) totallen); 683 break; 684 } 685 } else { 686 /* Start of APP0 does not match "JFIF" or "JFXX", or too short */ 687 TRACEMS1(cinfo, 1, JTRC_APP0, (int) totallen); 688 } 689 } 690 691 692 LOCAL(void) 693 examine_app14 (j_decompress_ptr cinfo, JOCTET FAR * data, 694 unsigned int datalen, INT32 remaining) 695 /* Examine first few bytes from an APP14. 696 * Take appropriate action if it is an Adobe marker. 697 * datalen is # of bytes at data[], remaining is length of rest of marker data. 698 */ 699 { 700 unsigned int version, flags0, flags1, transform; 701 702 if (datalen >= APP14_DATA_LEN && 703 GETJOCTET(data[0]) == 0x41 && 704 GETJOCTET(data[1]) == 0x64 && 705 GETJOCTET(data[2]) == 0x6F && 706 GETJOCTET(data[3]) == 0x62 && 707 GETJOCTET(data[4]) == 0x65) { 708 /* Found Adobe APP14 marker */ 709 version = (GETJOCTET(data[5]) << 8) + GETJOCTET(data[6]); 710 flags0 = (GETJOCTET(data[7]) << 8) + GETJOCTET(data[8]); 711 flags1 = (GETJOCTET(data[9]) << 8) + GETJOCTET(data[10]); 712 transform = GETJOCTET(data[11]); 713 TRACEMS4(cinfo, 1, JTRC_ADOBE, version, flags0, flags1, transform); 714 cinfo->saw_Adobe_marker = TRUE; 715 cinfo->Adobe_transform = (UINT8) transform; 716 } else { 717 /* Start of APP14 does not match "Adobe", or too short */ 718 TRACEMS1(cinfo, 1, JTRC_APP14, (int) (datalen + remaining)); 719 } 720 } 721 722 723 METHODDEF(boolean) 724 get_interesting_appn (j_decompress_ptr cinfo) 725 /* Process an APP0 or APP14 marker without saving it */ 726 { 727 INT32 length; 728 JOCTET b[APPN_DATA_LEN]; 729 unsigned int i, numtoread; 730 INPUT_VARS(cinfo); 731 732 INPUT_2BYTES(cinfo, length, return FALSE); 733 length -= 2; 734 735 /* get the interesting part of the marker data */ 736 if (length >= APPN_DATA_LEN) 737 numtoread = APPN_DATA_LEN; 738 else if (length > 0) 739 numtoread = (unsigned int) length; 740 else 741 numtoread = 0; 742 for (i = 0; i < numtoread; i++) 743 INPUT_BYTE(cinfo, b[i], return FALSE); 744 length -= numtoread; 745 746 /* process it */ 747 switch (cinfo->unread_marker) { 748 case M_APP0: 749 examine_app0(cinfo, (JOCTET FAR *) b, numtoread, length); 750 break; 751 case M_APP14: 752 examine_app14(cinfo, (JOCTET FAR *) b, numtoread, length); 753 break; 754 default: 755 /* can't get here unless jpeg_save_markers chooses wrong processor */ 756 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker); 757 break; 758 } 759 760 /* skip any remaining data -- could be lots */ 761 INPUT_SYNC(cinfo); 762 if (length > 0) 763 (*cinfo->src->skip_input_data) (cinfo, (long) length); 764 765 return TRUE; 766 } 767 768 769 #ifdef SAVE_MARKERS_SUPPORTED 770 771 METHODDEF(boolean) 772 save_marker (j_decompress_ptr cinfo) 773 /* Save an APPn or COM marker into the marker list */ 774 { 775 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 776 jpeg_saved_marker_ptr cur_marker = marker->cur_marker; 777 unsigned int bytes_read, data_length; 778 JOCTET FAR * data; 779 INT32 length = 0; 780 INPUT_VARS(cinfo); 781 782 if (cur_marker == NULL) { 783 /* begin reading a marker */ 784 INPUT_2BYTES(cinfo, length, return FALSE); 785 length -= 2; 786 if (length >= 0) { /* watch out for bogus length word */ 787 /* figure out how much we want to save */ 788 unsigned int limit; 789 if (cinfo->unread_marker == (int) M_COM) 790 limit = marker->length_limit_COM; 791 else 792 limit = marker->length_limit_APPn[cinfo->unread_marker - (int) M_APP0]; 793 if ((unsigned int) length < limit) 794 limit = (unsigned int) length; 795 /* allocate and initialize the marker item */ 796 cur_marker = (jpeg_saved_marker_ptr) 797 (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE, 798 SIZEOF(struct jpeg_marker_struct) + limit); 799 cur_marker->next = NULL; 800 cur_marker->marker = (UINT8) cinfo->unread_marker; 801 cur_marker->original_length = (unsigned int) length; 802 cur_marker->data_length = limit; 803 /* data area is just beyond the jpeg_marker_struct */ 804 data = cur_marker->data = (JOCTET FAR *) (cur_marker + 1); 805 marker->cur_marker = cur_marker; 806 marker->bytes_read = 0; 807 bytes_read = 0; 808 data_length = limit; 809 } else { 810 /* deal with bogus length word */ 811 bytes_read = data_length = 0; 812 data = NULL; 813 } 814 } else { 815 /* resume reading a marker */ 816 bytes_read = marker->bytes_read; 817 data_length = cur_marker->data_length; 818 data = cur_marker->data + bytes_read; 819 } 820 821 while (bytes_read < data_length) { 822 INPUT_SYNC(cinfo); /* move the restart point to here */ 823 marker->bytes_read = bytes_read; 824 /* If there's not at least one byte in buffer, suspend */ 825 MAKE_BYTE_AVAIL(cinfo, return FALSE); 826 /* Copy bytes with reasonable rapidity */ 827 while (bytes_read < data_length && bytes_in_buffer > 0) { 828 *data++ = *next_input_byte++; 829 bytes_in_buffer--; 830 bytes_read++; 831 } 832 } 833 834 /* Done reading what we want to read */ 835 if (cur_marker != NULL) { /* will be NULL if bogus length word */ 836 /* Add new marker to end of list */ 837 if (cinfo->marker_list == NULL) { 838 cinfo->marker_list = cur_marker; 839 } else { 840 jpeg_saved_marker_ptr prev = cinfo->marker_list; 841 while (prev->next != NULL) 842 prev = prev->next; 843 prev->next = cur_marker; 844 } 845 /* Reset pointer & calc remaining data length */ 846 data = cur_marker->data; 847 length = cur_marker->original_length - data_length; 848 } 849 /* Reset to initial state for next marker */ 850 marker->cur_marker = NULL; 851 852 /* Process the marker if interesting; else just make a generic trace msg */ 853 switch (cinfo->unread_marker) { 854 case M_APP0: 855 examine_app0(cinfo, data, data_length, length); 856 break; 857 case M_APP14: 858 examine_app14(cinfo, data, data_length, length); 859 break; 860 default: 861 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, 862 (int) (data_length + length)); 863 break; 864 } 865 866 /* skip any remaining data -- could be lots */ 867 INPUT_SYNC(cinfo); /* do before skip_input_data */ 868 if (length > 0) 869 (*cinfo->src->skip_input_data) (cinfo, (long) length); 870 871 return TRUE; 872 } 873 874 #endif /* SAVE_MARKERS_SUPPORTED */ 875 876 877 METHODDEF(boolean) 878 skip_variable (j_decompress_ptr cinfo) 879 /* Skip over an unknown or uninteresting variable-length marker */ 880 { 881 INT32 length; 882 INPUT_VARS(cinfo); 883 884 INPUT_2BYTES(cinfo, length, return FALSE); 885 length -= 2; 886 887 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, (int) length); 888 889 INPUT_SYNC(cinfo); /* do before skip_input_data */ 890 if (length > 0) 891 (*cinfo->src->skip_input_data) (cinfo, (long) length); 892 893 return TRUE; 894 } 895 896 897 /* 898 * Find the next JPEG marker, save it in cinfo->unread_marker. 899 * Returns FALSE if had to suspend before reaching a marker; 900 * in that case cinfo->unread_marker is unchanged. 901 * 902 * Note that the result might not be a valid marker code, 903 * but it will never be 0 or FF. 904 */ 905 906 LOCAL(boolean) 907 next_marker (j_decompress_ptr cinfo) 908 { 909 int c; 910 INPUT_VARS(cinfo); 911 912 for (;;) { 913 INPUT_BYTE(cinfo, c, return FALSE); 914 /* Skip any non-FF bytes. 915 * This may look a bit inefficient, but it will not occur in a valid file. 916 * We sync after each discarded byte so that a suspending data source 917 * can discard the byte from its buffer. 918 */ 919 while (c != 0xFF) { 920 cinfo->marker->discarded_bytes++; 921 INPUT_SYNC(cinfo); 922 INPUT_BYTE(cinfo, c, return FALSE); 923 } 924 /* This loop swallows any duplicate FF bytes. Extra FFs are legal as 925 * pad bytes, so don't count them in discarded_bytes. We assume there 926 * will not be so many consecutive FF bytes as to overflow a suspending 927 * data source's input buffer. 928 */ 929 do { 930 INPUT_BYTE(cinfo, c, return FALSE); 931 } while (c == 0xFF); 932 if (c != 0) 933 break; /* found a valid marker, exit loop */ 934 /* Reach here if we found a stuffed-zero data sequence (FF/00). 935 * Discard it and loop back to try again. 936 */ 937 cinfo->marker->discarded_bytes += 2; 938 INPUT_SYNC(cinfo); 939 } 940 941 if (cinfo->marker->discarded_bytes != 0) { 942 WARNMS2(cinfo, JWRN_EXTRANEOUS_DATA, cinfo->marker->discarded_bytes, c); 943 cinfo->marker->discarded_bytes = 0; 944 } 945 946 cinfo->unread_marker = c; 947 948 INPUT_SYNC(cinfo); 949 return TRUE; 950 } 951 952 953 LOCAL(boolean) 954 first_marker (j_decompress_ptr cinfo) 955 /* Like next_marker, but used to obtain the initial SOI marker. */ 956 /* For this marker, we do not allow preceding garbage or fill; otherwise, 957 * we might well scan an entire input file before realizing it ain't JPEG. 958 * If an application wants to process non-JFIF files, it must seek to the 959 * SOI before calling the JPEG library. 960 */ 961 { 962 int c, c2; 963 INPUT_VARS(cinfo); 964 965 INPUT_BYTE(cinfo, c, return FALSE); 966 INPUT_BYTE(cinfo, c2, return FALSE); 967 if (c != 0xFF || c2 != (int) M_SOI) 968 ERREXIT2(cinfo, JERR_NO_SOI, c, c2); 969 970 cinfo->unread_marker = c2; 971 972 INPUT_SYNC(cinfo); 973 return TRUE; 974 } 975 976 977 /* 978 * Read markers until SOS or EOI. 979 * 980 * Returns same codes as are defined for jpeg_consume_input: 981 * JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI. 982 */ 983 984 METHODDEF(int) 985 read_markers (j_decompress_ptr cinfo) 986 { 987 /* Outer loop repeats once for each marker. */ 988 for (;;) { 989 /* Collect the marker proper, unless we already did. */ 990 /* NB: first_marker() enforces the requirement that SOI appear first. */ 991 if (cinfo->unread_marker == 0) { 992 if (! cinfo->marker->saw_SOI) { 993 if (! first_marker(cinfo)) 994 return JPEG_SUSPENDED; 995 } else { 996 if (! next_marker(cinfo)) 997 return JPEG_SUSPENDED; 998 } 999 } 1000 /* At this point cinfo->unread_marker contains the marker code and the 1001 * input point is just past the marker proper, but before any parameters. 1002 * A suspension will cause us to return with this state still true. 1003 */ 1004 switch (cinfo->unread_marker) { 1005 case M_SOI: 1006 if (! get_soi(cinfo)) 1007 return JPEG_SUSPENDED; 1008 break; 1009 1010 case M_SOF0: /* Baseline */ 1011 case M_SOF1: /* Extended sequential, Huffman */ 1012 if (! get_sof(cinfo, FALSE, FALSE)) 1013 return JPEG_SUSPENDED; 1014 break; 1015 1016 case M_SOF2: /* Progressive, Huffman */ 1017 if (! get_sof(cinfo, TRUE, FALSE)) 1018 return JPEG_SUSPENDED; 1019 break; 1020 1021 case M_SOF9: /* Extended sequential, arithmetic */ 1022 if (! get_sof(cinfo, FALSE, TRUE)) 1023 return JPEG_SUSPENDED; 1024 break; 1025 1026 case M_SOF10: /* Progressive, arithmetic */ 1027 if (! get_sof(cinfo, TRUE, TRUE)) 1028 return JPEG_SUSPENDED; 1029 break; 1030 1031 /* Currently unsupported SOFn types */ 1032 case M_SOF3: /* Lossless, Huffman */ 1033 case M_SOF5: /* Differential sequential, Huffman */ 1034 case M_SOF6: /* Differential progressive, Huffman */ 1035 case M_SOF7: /* Differential lossless, Huffman */ 1036 case M_JPG: /* Reserved for JPEG extensions */ 1037 case M_SOF11: /* Lossless, arithmetic */ 1038 case M_SOF13: /* Differential sequential, arithmetic */ 1039 case M_SOF14: /* Differential progressive, arithmetic */ 1040 case M_SOF15: /* Differential lossless, arithmetic */ 1041 ERREXIT1(cinfo, JERR_SOF_UNSUPPORTED, cinfo->unread_marker); 1042 break; 1043 1044 case M_SOS: 1045 if (! get_sos(cinfo)) 1046 return JPEG_SUSPENDED; 1047 cinfo->unread_marker = 0; /* processed the marker */ 1048 return JPEG_REACHED_SOS; 1049 1050 case M_EOI: 1051 TRACEMS(cinfo, 1, JTRC_EOI); 1052 cinfo->unread_marker = 0; /* processed the marker */ 1053 return JPEG_REACHED_EOI; 1054 1055 case M_DAC: 1056 if (! get_dac(cinfo)) 1057 return JPEG_SUSPENDED; 1058 break; 1059 1060 case M_DHT: 1061 if (! get_dht(cinfo)) 1062 return JPEG_SUSPENDED; 1063 break; 1064 1065 case M_DQT: 1066 if (! get_dqt(cinfo)) 1067 return JPEG_SUSPENDED; 1068 break; 1069 1070 case M_DRI: 1071 if (! get_dri(cinfo)) 1072 return JPEG_SUSPENDED; 1073 break; 1074 1075 case M_APP0: 1076 case M_APP1: 1077 case M_APP2: 1078 case M_APP3: 1079 case M_APP4: 1080 case M_APP5: 1081 case M_APP6: 1082 case M_APP7: 1083 case M_APP8: 1084 case M_APP9: 1085 case M_APP10: 1086 case M_APP11: 1087 case M_APP12: 1088 case M_APP13: 1089 case M_APP14: 1090 case M_APP15: 1091 if (! (*((my_marker_ptr) cinfo->marker)->process_APPn[ 1092 cinfo->unread_marker - (int) M_APP0]) (cinfo)) 1093 return JPEG_SUSPENDED; 1094 break; 1095 1096 case M_COM: 1097 if (! (*((my_marker_ptr) cinfo->marker)->process_COM) (cinfo)) 1098 return JPEG_SUSPENDED; 1099 break; 1100 1101 case M_RST0: /* these are all parameterless */ 1102 case M_RST1: 1103 case M_RST2: 1104 case M_RST3: 1105 case M_RST4: 1106 case M_RST5: 1107 case M_RST6: 1108 case M_RST7: 1109 case M_TEM: 1110 TRACEMS1(cinfo, 1, JTRC_PARMLESS_MARKER, cinfo->unread_marker); 1111 break; 1112 1113 case M_DNL: /* Ignore DNL ... perhaps the wrong thing */ 1114 if (! skip_variable(cinfo)) 1115 return JPEG_SUSPENDED; 1116 break; 1117 1118 default: /* must be DHP, EXP, JPGn, or RESn */ 1119 /* For now, we treat the reserved markers as fatal errors since they are 1120 * likely to be used to signal incompatible JPEG Part 3 extensions. 1121 * Once the JPEG 3 version-number marker is well defined, this code 1122 * ought to change! 1123 */ 1124 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker); 1125 break; 1126 } 1127 /* Successfully processed marker, so reset state variable */ 1128 cinfo->unread_marker = 0; 1129 } /* end loop */ 1130 } 1131 1132 1133 /* 1134 * Read a restart marker, which is expected to appear next in the datastream; 1135 * if the marker is not there, take appropriate recovery action. 1136 * Returns FALSE if suspension is required. 1137 * 1138 * This is called by the entropy decoder after it has read an appropriate 1139 * number of MCUs. cinfo->unread_marker may be nonzero if the entropy decoder 1140 * has already read a marker from the data source. Under normal conditions 1141 * cinfo->unread_marker will be reset to 0 before returning; if not reset, 1142 * it holds a marker which the decoder will be unable to read past. 1143 */ 1144 1145 METHODDEF(boolean) 1146 read_restart_marker (j_decompress_ptr cinfo) 1147 { 1148 /* Obtain a marker unless we already did. */ 1149 /* Note that next_marker will complain if it skips any data. */ 1150 if (cinfo->unread_marker == 0) { 1151 if (! next_marker(cinfo)) 1152 return FALSE; 1153 } 1154 1155 if (cinfo->unread_marker == 1156 ((int) M_RST0 + cinfo->marker->next_restart_num)) { 1157 /* Normal case --- swallow the marker and let entropy decoder continue */ 1158 TRACEMS1(cinfo, 3, JTRC_RST, cinfo->marker->next_restart_num); 1159 cinfo->unread_marker = 0; 1160 } else { 1161 /* Uh-oh, the restart markers have been messed up. */ 1162 /* Let the data source manager determine how to resync. */ 1163 if (! (*cinfo->src->resync_to_restart) (cinfo, 1164 cinfo->marker->next_restart_num)) 1165 return FALSE; 1166 } 1167 1168 /* Update next-restart state */ 1169 cinfo->marker->next_restart_num = (cinfo->marker->next_restart_num + 1) & 7; 1170 1171 return TRUE; 1172 } 1173 1174 1175 /* 1176 * This is the default resync_to_restart method for data source managers 1177 * to use if they don't have any better approach. Some data source managers 1178 * may be able to back up, or may have additional knowledge about the data 1179 * which permits a more intelligent recovery strategy; such managers would 1180 * presumably supply their own resync method. 1181 * 1182 * read_restart_marker calls resync_to_restart if it finds a marker other than 1183 * the restart marker it was expecting. (This code is *not* used unless 1184 * a nonzero restart interval has been declared.) cinfo->unread_marker is 1185 * the marker code actually found (might be anything, except 0 or FF). 1186 * The desired restart marker number (0..7) is passed as a parameter. 1187 * This routine is supposed to apply whatever error recovery strategy seems 1188 * appropriate in order to position the input stream to the next data segment. 1189 * Note that cinfo->unread_marker is treated as a marker appearing before 1190 * the current data-source input point; usually it should be reset to zero 1191 * before returning. 1192 * Returns FALSE if suspension is required. 1193 * 1194 * This implementation is substantially constrained by wanting to treat the 1195 * input as a data stream; this means we can't back up. Therefore, we have 1196 * only the following actions to work with: 1197 * 1. Simply discard the marker and let the entropy decoder resume at next 1198 * byte of file. 1199 * 2. Read forward until we find another marker, discarding intervening 1200 * data. (In theory we could look ahead within the current bufferload, 1201 * without having to discard data if we don't find the desired marker. 1202 * This idea is not implemented here, in part because it makes behavior 1203 * dependent on buffer size and chance buffer-boundary positions.) 1204 * 3. Leave the marker unread (by failing to zero cinfo->unread_marker). 1205 * This will cause the entropy decoder to process an empty data segment, 1206 * inserting dummy zeroes, and then we will reprocess the marker. 1207 * 1208 * #2 is appropriate if we think the desired marker lies ahead, while #3 is 1209 * appropriate if the found marker is a future restart marker (indicating 1210 * that we have missed the desired restart marker, probably because it got 1211 * corrupted). 1212 * We apply #2 or #3 if the found marker is a restart marker no more than 1213 * two counts behind or ahead of the expected one. We also apply #2 if the 1214 * found marker is not a legal JPEG marker code (it's certainly bogus data). 1215 * If the found marker is a restart marker more than 2 counts away, we do #1 1216 * (too much risk that the marker is erroneous; with luck we will be able to 1217 * resync at some future point). 1218 * For any valid non-restart JPEG marker, we apply #3. This keeps us from 1219 * overrunning the end of a scan. An implementation limited to single-scan 1220 * files might find it better to apply #2 for markers other than EOI, since 1221 * any other marker would have to be bogus data in that case. 1222 */ 1223 1224 GLOBAL(boolean) 1225 jpeg_resync_to_restart (j_decompress_ptr cinfo, int desired) 1226 { 1227 int marker = cinfo->unread_marker; 1228 int action = 1; 1229 1230 /* Always put up a warning. */ 1231 WARNMS2(cinfo, JWRN_MUST_RESYNC, marker, desired); 1232 1233 /* Outer loop handles repeated decision after scanning forward. */ 1234 for (;;) { 1235 if (marker < (int) M_SOF0) 1236 action = 2; /* invalid marker */ 1237 else if (marker < (int) M_RST0 || marker > (int) M_RST7) 1238 action = 3; /* valid non-restart marker */ 1239 else { 1240 if (marker == ((int) M_RST0 + ((desired+1) & 7)) || 1241 marker == ((int) M_RST0 + ((desired+2) & 7))) 1242 action = 3; /* one of the next two expected restarts */ 1243 else if (marker == ((int) M_RST0 + ((desired-1) & 7)) || 1244 marker == ((int) M_RST0 + ((desired-2) & 7))) 1245 action = 2; /* a prior restart, so advance */ 1246 else 1247 action = 1; /* desired restart or too far away */ 1248 } 1249 TRACEMS2(cinfo, 4, JTRC_RECOVERY_ACTION, marker, action); 1250 switch (action) { 1251 case 1: 1252 /* Discard marker and let entropy decoder resume processing. */ 1253 cinfo->unread_marker = 0; 1254 return TRUE; 1255 case 2: 1256 /* Scan to the next marker, and repeat the decision loop. */ 1257 if (! next_marker(cinfo)) 1258 return FALSE; 1259 marker = cinfo->unread_marker; 1260 break; 1261 case 3: 1262 /* Return without advancing past this marker. */ 1263 /* Entropy decoder will be forced to process an empty segment. */ 1264 return TRUE; 1265 } 1266 } /* end loop */ 1267 } 1268 1269 1270 /* 1271 * Reset marker processing state to begin a fresh datastream. 1272 */ 1273 1274 METHODDEF(void) 1275 reset_marker_reader (j_decompress_ptr cinfo) 1276 { 1277 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 1278 1279 cinfo->comp_info = NULL; /* until allocated by get_sof */ 1280 cinfo->input_scan_number = 0; /* no SOS seen yet */ 1281 cinfo->unread_marker = 0; /* no pending marker */ 1282 marker->pub.saw_SOI = FALSE; /* set internal state too */ 1283 marker->pub.saw_SOF = FALSE; 1284 marker->pub.discarded_bytes = 0; 1285 marker->cur_marker = NULL; 1286 } 1287 1288 1289 /* 1290 * Initialize the marker reader module. 1291 * This is called only once, when the decompression object is created. 1292 */ 1293 1294 GLOBAL(void) 1295 jinit_marker_reader (j_decompress_ptr cinfo) 1296 { 1297 my_marker_ptr marker; 1298 int i; 1299 1300 /* Create subobject in permanent pool */ 1301 marker = (my_marker_ptr) 1302 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT, 1303 SIZEOF(my_marker_reader)); 1304 cinfo->marker = (struct jpeg_marker_reader *) marker; 1305 /* Initialize public method pointers */ 1306 marker->pub.reset_marker_reader = reset_marker_reader; 1307 marker->pub.read_markers = read_markers; 1308 marker->pub.read_restart_marker = read_restart_marker; 1309 /* Initialize COM/APPn processing. 1310 * By default, we examine and then discard APP0 and APP14, 1311 * but simply discard COM and all other APPn. 1312 */ 1313 marker->process_COM = skip_variable; 1314 marker->length_limit_COM = 0; 1315 for (i = 0; i < 16; i++) { 1316 marker->process_APPn[i] = skip_variable; 1317 marker->length_limit_APPn[i] = 0; 1318 } 1319 marker->process_APPn[0] = get_interesting_appn; 1320 marker->process_APPn[14] = get_interesting_appn; 1321 /* Reset marker processing state */ 1322 reset_marker_reader(cinfo); 1323 } 1324 1325 1326 /* 1327 * Control saving of COM and APPn markers into marker_list. 1328 */ 1329 1330 #ifdef SAVE_MARKERS_SUPPORTED 1331 1332 GLOBAL(void) 1333 jpeg_save_markers (j_decompress_ptr cinfo, int marker_code, 1334 unsigned int length_limit) 1335 { 1336 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 1337 long maxlength; 1338 jpeg_marker_parser_method processor; 1339 1340 /* Length limit mustn't be larger than what we can allocate 1341 * (should only be a concern in a 16-bit environment). 1342 */ 1343 maxlength = cinfo->mem->max_alloc_chunk - SIZEOF(struct jpeg_marker_struct); 1344 if (((long) length_limit) > maxlength) 1345 length_limit = (unsigned int) maxlength; 1346 1347 /* Choose processor routine to use. 1348 * APP0/APP14 have special requirements. 1349 */ 1350 if (length_limit) { 1351 processor = save_marker; 1352 /* If saving APP0/APP14, save at least enough for our internal use. */ 1353 if (marker_code == (int) M_APP0 && length_limit < APP0_DATA_LEN) 1354 length_limit = APP0_DATA_LEN; 1355 else if (marker_code == (int) M_APP14 && length_limit < APP14_DATA_LEN) 1356 length_limit = APP14_DATA_LEN; 1357 } else { 1358 processor = skip_variable; 1359 /* If discarding APP0/APP14, use our regular on-the-fly processor. */ 1360 if (marker_code == (int) M_APP0 || marker_code == (int) M_APP14) 1361 processor = get_interesting_appn; 1362 } 1363 1364 if (marker_code == (int) M_COM) { 1365 marker->process_COM = processor; 1366 marker->length_limit_COM = length_limit; 1367 } else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15) { 1368 marker->process_APPn[marker_code - (int) M_APP0] = processor; 1369 marker->length_limit_APPn[marker_code - (int) M_APP0] = length_limit; 1370 } else 1371 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code); 1372 } 1373 1374 #endif /* SAVE_MARKERS_SUPPORTED */ 1375 1376 1377 /* 1378 * Install a special processing method for COM or APPn markers. 1379 */ 1380 1381 GLOBAL(void) 1382 jpeg_set_marker_processor (j_decompress_ptr cinfo, int marker_code, 1383 jpeg_marker_parser_method routine) 1384 { 1385 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 1386 1387 if (marker_code == (int) M_COM) 1388 marker->process_COM = routine; 1389 else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15) 1390 marker->process_APPn[marker_code - (int) M_APP0] = routine; 1391 else 1392 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code); 1393 } 1394
