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 INPUT_VARS(cinfo); 244 245 cinfo->progressive_mode = is_prog; 246 cinfo->arith_code = is_arith; 247 248 INPUT_2BYTES(cinfo, length, return FALSE); 249 250 INPUT_BYTE(cinfo, cinfo->data_precision, return FALSE); 251 INPUT_2BYTES(cinfo, cinfo->image_height, return FALSE); 252 INPUT_2BYTES(cinfo, cinfo->image_width, return FALSE); 253 INPUT_BYTE(cinfo, cinfo->num_components, return FALSE); 254 255 length -= 8; 256 257 TRACEMS4(cinfo, 1, JTRC_SOF, cinfo->unread_marker, 258 (int) cinfo->image_width, (int) cinfo->image_height, 259 cinfo->num_components); 260 261 if (cinfo->marker->saw_SOF) 262 ERREXIT(cinfo, JERR_SOF_DUPLICATE); 263 264 /* We don't support files in which the image height is initially specified */ 265 /* as 0 and is later redefined by DNL. As long as we have to check that, */ 266 /* might as well have a general sanity check. */ 267 if (cinfo->image_height <= 0 || cinfo->image_width <= 0 268 || cinfo->num_components <= 0) 269 ERREXIT(cinfo, JERR_EMPTY_IMAGE); 270 271 if (length != (cinfo->num_components * 3)) 272 ERREXIT(cinfo, JERR_BAD_LENGTH); 273 274 if (cinfo->comp_info == NULL) /* do only once, even if suspend */ 275 cinfo->comp_info = (jpeg_component_info *) (*cinfo->mem->alloc_small) 276 ((j_common_ptr) cinfo, JPOOL_IMAGE, 277 cinfo->num_components * SIZEOF(jpeg_component_info)); 278 279 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 280 ci++, compptr++) { 281 compptr->component_index = ci; 282 INPUT_BYTE(cinfo, compptr->component_id, return FALSE); 283 INPUT_BYTE(cinfo, c, return FALSE); 284 compptr->h_samp_factor = (c >> 4) & 15; 285 compptr->v_samp_factor = (c ) & 15; 286 INPUT_BYTE(cinfo, compptr->quant_tbl_no, return FALSE); 287 288 TRACEMS4(cinfo, 1, JTRC_SOF_COMPONENT, 289 compptr->component_id, compptr->h_samp_factor, 290 compptr->v_samp_factor, compptr->quant_tbl_no); 291 } 292 293 cinfo->marker->saw_SOF = TRUE; 294 295 INPUT_SYNC(cinfo); 296 return TRUE; 297 } 298 299 300 LOCAL(boolean) 301 get_sos (j_decompress_ptr cinfo) 302 /* Process a SOS marker */ 303 { 304 INT32 length; 305 int i, ci, n, c, cc, pi; 306 jpeg_component_info * compptr; 307 INPUT_VARS(cinfo); 308 309 if (! cinfo->marker->saw_SOF) 310 ERREXIT(cinfo, JERR_SOS_NO_SOF); 311 312 INPUT_2BYTES(cinfo, length, return FALSE); 313 314 INPUT_BYTE(cinfo, n, return FALSE); /* Number of components */ 315 316 TRACEMS1(cinfo, 1, JTRC_SOS, n); 317 318 if (length != (n * 2 + 6) || n < 1 || n > MAX_COMPS_IN_SCAN) 319 ERREXIT(cinfo, JERR_BAD_LENGTH); 320 321 cinfo->comps_in_scan = n; 322 323 /* Collect the component-spec parameters */ 324 325 for (i = 0; i < n; i++) { 326 INPUT_BYTE(cinfo, cc, return FALSE); 327 INPUT_BYTE(cinfo, c, return FALSE); 328 329 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 330 ci++, compptr++) { 331 if (cc == compptr->component_id) 332 goto id_found; 333 } 334 335 ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc); 336 337 id_found: 338 339 cinfo->cur_comp_info[i] = compptr; 340 compptr->dc_tbl_no = (c >> 4) & 15; 341 compptr->ac_tbl_no = (c ) & 15; 342 343 TRACEMS3(cinfo, 1, JTRC_SOS_COMPONENT, cc, 344 compptr->dc_tbl_no, compptr->ac_tbl_no); 345 346 /* This CSi (cc) should differ from the previous CSi */ 347 for (pi = 0; pi < i; pi++) { 348 if (cinfo->cur_comp_info[pi] == compptr) 349 ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc); 350 } 351 } 352 353 /* Collect the additional scan parameters Ss, Se, Ah/Al. */ 354 INPUT_BYTE(cinfo, c, return FALSE); 355 cinfo->Ss = c; 356 INPUT_BYTE(cinfo, c, return FALSE); 357 cinfo->Se = c; 358 INPUT_BYTE(cinfo, c, return FALSE); 359 cinfo->Ah = (c >> 4) & 15; 360 cinfo->Al = (c ) & 15; 361 362 TRACEMS4(cinfo, 1, JTRC_SOS_PARAMS, cinfo->Ss, cinfo->Se, 363 cinfo->Ah, cinfo->Al); 364 365 /* Prepare to scan data & restart markers */ 366 cinfo->marker->next_restart_num = 0; 367 368 /* Count another SOS marker */ 369 cinfo->input_scan_number++; 370 371 INPUT_SYNC(cinfo); 372 return TRUE; 373 } 374 375 376 #ifdef D_ARITH_CODING_SUPPORTED 377 378 LOCAL(boolean) 379 get_dac (j_decompress_ptr cinfo) 380 /* Process a DAC marker */ 381 { 382 INT32 length; 383 int index, val; 384 INPUT_VARS(cinfo); 385 386 INPUT_2BYTES(cinfo, length, return FALSE); 387 length -= 2; 388 389 while (length > 0) { 390 INPUT_BYTE(cinfo, index, return FALSE); 391 INPUT_BYTE(cinfo, val, return FALSE); 392 393 length -= 2; 394 395 TRACEMS2(cinfo, 1, JTRC_DAC, index, val); 396 397 if (index < 0 || index >= (2*NUM_ARITH_TBLS)) 398 ERREXIT1(cinfo, JERR_DAC_INDEX, index); 399 400 if (index >= NUM_ARITH_TBLS) { /* define AC table */ 401 cinfo->arith_ac_K[index-NUM_ARITH_TBLS] = (UINT8) val; 402 } else { /* define DC table */ 403 cinfo->arith_dc_L[index] = (UINT8) (val & 0x0F); 404 cinfo->arith_dc_U[index] = (UINT8) (val >> 4); 405 if (cinfo->arith_dc_L[index] > cinfo->arith_dc_U[index]) 406 ERREXIT1(cinfo, JERR_DAC_VALUE, val); 407 } 408 } 409 410 if (length != 0) 411 ERREXIT(cinfo, JERR_BAD_LENGTH); 412 413 INPUT_SYNC(cinfo); 414 return TRUE; 415 } 416 417 #else /* ! D_ARITH_CODING_SUPPORTED */ 418 419 #define get_dac(cinfo) skip_variable(cinfo) 420 421 #endif /* D_ARITH_CODING_SUPPORTED */ 422 423 424 LOCAL(boolean) 425 get_dht (j_decompress_ptr cinfo) 426 /* Process a DHT marker */ 427 { 428 INT32 length; 429 UINT8 bits[17]; 430 UINT8 huffval[256]; 431 int i, index, count; 432 JHUFF_TBL **htblptr; 433 INPUT_VARS(cinfo); 434 435 INPUT_2BYTES(cinfo, length, return FALSE); 436 length -= 2; 437 438 while (length > 16) { 439 INPUT_BYTE(cinfo, index, return FALSE); 440 441 TRACEMS1(cinfo, 1, JTRC_DHT, index); 442 443 bits[0] = 0; 444 count = 0; 445 for (i = 1; i <= 16; i++) { 446 INPUT_BYTE(cinfo, bits[i], return FALSE); 447 count += bits[i]; 448 } 449 450 length -= 1 + 16; 451 452 TRACEMS8(cinfo, 2, JTRC_HUFFBITS, 453 bits[1], bits[2], bits[3], bits[4], 454 bits[5], bits[6], bits[7], bits[8]); 455 TRACEMS8(cinfo, 2, JTRC_HUFFBITS, 456 bits[9], bits[10], bits[11], bits[12], 457 bits[13], bits[14], bits[15], bits[16]); 458 459 /* Here we just do minimal validation of the counts to avoid walking 460 * off the end of our table space. jdhuff.c will check more carefully. 461 */ 462 if (count > 256 || ((INT32) count) > length) 463 ERREXIT(cinfo, JERR_BAD_HUFF_TABLE); 464 465 for (i = 0; i < count; i++) 466 INPUT_BYTE(cinfo, huffval[i], return FALSE); 467 468 MEMZERO(&huffval[count], (256 - count) * SIZEOF(UINT8)); 469 470 length -= count; 471 472 if (index & 0x10) { /* AC table definition */ 473 index -= 0x10; 474 htblptr = &cinfo->ac_huff_tbl_ptrs[index]; 475 } else { /* DC table definition */ 476 htblptr = &cinfo->dc_huff_tbl_ptrs[index]; 477 } 478 479 if (index < 0 || index >= NUM_HUFF_TBLS) 480 ERREXIT1(cinfo, JERR_DHT_INDEX, index); 481 482 if (*htblptr == NULL) 483 *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo); 484 485 MEMCOPY((*htblptr)->bits, bits, SIZEOF((*htblptr)->bits)); 486 MEMCOPY((*htblptr)->huffval, huffval, SIZEOF((*htblptr)->huffval)); 487 } 488 489 if (length != 0) 490 ERREXIT(cinfo, JERR_BAD_LENGTH); 491 492 INPUT_SYNC(cinfo); 493 return TRUE; 494 } 495 496 497 LOCAL(boolean) 498 get_dqt (j_decompress_ptr cinfo) 499 /* Process a DQT marker */ 500 { 501 INT32 length; 502 int n, i, prec; 503 unsigned int tmp; 504 JQUANT_TBL *quant_ptr; 505 INPUT_VARS(cinfo); 506 507 INPUT_2BYTES(cinfo, length, return FALSE); 508 length -= 2; 509 510 while (length > 0) { 511 INPUT_BYTE(cinfo, n, return FALSE); 512 prec = n >> 4; 513 n &= 0x0F; 514 515 TRACEMS2(cinfo, 1, JTRC_DQT, n, prec); 516 517 if (n >= NUM_QUANT_TBLS) 518 ERREXIT1(cinfo, JERR_DQT_INDEX, n); 519 520 if (cinfo->quant_tbl_ptrs[n] == NULL) 521 cinfo->quant_tbl_ptrs[n] = jpeg_alloc_quant_table((j_common_ptr) cinfo); 522 quant_ptr = cinfo->quant_tbl_ptrs[n]; 523 524 for (i = 0; i < DCTSIZE2; i++) { 525 if (prec) 526 INPUT_2BYTES(cinfo, tmp, return FALSE); 527 else 528 INPUT_BYTE(cinfo, tmp, return FALSE); 529 /* We convert the zigzag-order table to natural array order. */ 530 quant_ptr->quantval[jpeg_natural_order[i]] = (UINT16) tmp; 531 } 532 533 if (cinfo->err->trace_level >= 2) { 534 for (i = 0; i < DCTSIZE2; i += 8) { 535 TRACEMS8(cinfo, 2, JTRC_QUANTVALS, 536 quant_ptr->quantval[i], quant_ptr->quantval[i+1], 537 quant_ptr->quantval[i+2], quant_ptr->quantval[i+3], 538 quant_ptr->quantval[i+4], quant_ptr->quantval[i+5], 539 quant_ptr->quantval[i+6], quant_ptr->quantval[i+7]); 540 } 541 } 542 543 length -= DCTSIZE2+1; 544 if (prec) length -= DCTSIZE2; 545 } 546 547 if (length != 0) 548 ERREXIT(cinfo, JERR_BAD_LENGTH); 549 550 INPUT_SYNC(cinfo); 551 return TRUE; 552 } 553 554 555 LOCAL(boolean) 556 get_dri (j_decompress_ptr cinfo) 557 /* Process a DRI marker */ 558 { 559 INT32 length; 560 unsigned int tmp; 561 INPUT_VARS(cinfo); 562 563 INPUT_2BYTES(cinfo, length, return FALSE); 564 565 if (length != 4) 566 ERREXIT(cinfo, JERR_BAD_LENGTH); 567 568 INPUT_2BYTES(cinfo, tmp, return FALSE); 569 570 TRACEMS1(cinfo, 1, JTRC_DRI, tmp); 571 572 cinfo->restart_interval = tmp; 573 574 INPUT_SYNC(cinfo); 575 return TRUE; 576 } 577 578 579 /* 580 * Routines for processing APPn and COM markers. 581 * These are either saved in memory or discarded, per application request. 582 * APP0 and APP14 are specially checked to see if they are 583 * JFIF and Adobe markers, respectively. 584 */ 585 586 #define APP0_DATA_LEN 14 /* Length of interesting data in APP0 */ 587 #define APP14_DATA_LEN 12 /* Length of interesting data in APP14 */ 588 #define APPN_DATA_LEN 14 /* Must be the largest of the above!! */ 589 590 591 LOCAL(void) 592 examine_app0 (j_decompress_ptr cinfo, JOCTET FAR * data, 593 unsigned int datalen, INT32 remaining) 594 /* Examine first few bytes from an APP0. 595 * Take appropriate action if it is a JFIF marker. 596 * datalen is # of bytes at data[], remaining is length of rest of marker data. 597 */ 598 { 599 INT32 totallen = (INT32) datalen + remaining; 600 601 if (datalen >= APP0_DATA_LEN && 602 GETJOCTET(data[0]) == 0x4A && 603 GETJOCTET(data[1]) == 0x46 && 604 GETJOCTET(data[2]) == 0x49 && 605 GETJOCTET(data[3]) == 0x46 && 606 GETJOCTET(data[4]) == 0) { 607 /* Found JFIF APP0 marker: save info */ 608 cinfo->saw_JFIF_marker = TRUE; 609 cinfo->JFIF_major_version = GETJOCTET(data[5]); 610 cinfo->JFIF_minor_version = GETJOCTET(data[6]); 611 cinfo->density_unit = GETJOCTET(data[7]); 612 cinfo->X_density = (GETJOCTET(data[8]) << 8) + GETJOCTET(data[9]); 613 cinfo->Y_density = (GETJOCTET(data[10]) << 8) + GETJOCTET(data[11]); 614 /* Check version. 615 * Major version must be 1, anything else signals an incompatible change. 616 * (We used to treat this as an error, but now it's a nonfatal warning, 617 * because some bozo at Hijaak couldn't read the spec.) 618 * Minor version should be 0..2, but process anyway if newer. 619 */ 620 if (cinfo->JFIF_major_version != 1) 621 WARNMS2(cinfo, JWRN_JFIF_MAJOR, 622 cinfo->JFIF_major_version, cinfo->JFIF_minor_version); 623 /* Generate trace messages */ 624 TRACEMS5(cinfo, 1, JTRC_JFIF, 625 cinfo->JFIF_major_version, cinfo->JFIF_minor_version, 626 cinfo->X_density, cinfo->Y_density, cinfo->density_unit); 627 /* Validate thumbnail dimensions and issue appropriate messages */ 628 if (GETJOCTET(data[12]) | GETJOCTET(data[13])) 629 TRACEMS2(cinfo, 1, JTRC_JFIF_THUMBNAIL, 630 GETJOCTET(data[12]), GETJOCTET(data[13])); 631 totallen -= APP0_DATA_LEN; 632 if (totallen != 633 ((INT32)GETJOCTET(data[12]) * (INT32)GETJOCTET(data[13]) * (INT32) 3)) 634 TRACEMS1(cinfo, 1, JTRC_JFIF_BADTHUMBNAILSIZE, (int) totallen); 635 } else if (datalen >= 6 && 636 GETJOCTET(data[0]) == 0x4A && 637 GETJOCTET(data[1]) == 0x46 && 638 GETJOCTET(data[2]) == 0x58 && 639 GETJOCTET(data[3]) == 0x58 && 640 GETJOCTET(data[4]) == 0) { 641 /* Found JFIF "JFXX" extension APP0 marker */ 642 /* The library doesn't actually do anything with these, 643 * but we try to produce a helpful trace message. 644 */ 645 switch (GETJOCTET(data[5])) { 646 case 0x10: 647 TRACEMS1(cinfo, 1, JTRC_THUMB_JPEG, (int) totallen); 648 break; 649 case 0x11: 650 TRACEMS1(cinfo, 1, JTRC_THUMB_PALETTE, (int) totallen); 651 break; 652 case 0x13: 653 TRACEMS1(cinfo, 1, JTRC_THUMB_RGB, (int) totallen); 654 break; 655 default: 656 TRACEMS2(cinfo, 1, JTRC_JFIF_EXTENSION, 657 GETJOCTET(data[5]), (int) totallen); 658 break; 659 } 660 } else { 661 /* Start of APP0 does not match "JFIF" or "JFXX", or too short */ 662 TRACEMS1(cinfo, 1, JTRC_APP0, (int) totallen); 663 } 664 } 665 666 667 LOCAL(void) 668 examine_app14 (j_decompress_ptr cinfo, JOCTET FAR * data, 669 unsigned int datalen, INT32 remaining) 670 /* Examine first few bytes from an APP14. 671 * Take appropriate action if it is an Adobe marker. 672 * datalen is # of bytes at data[], remaining is length of rest of marker data. 673 */ 674 { 675 unsigned int version, flags0, flags1, transform; 676 677 if (datalen >= APP14_DATA_LEN && 678 GETJOCTET(data[0]) == 0x41 && 679 GETJOCTET(data[1]) == 0x64 && 680 GETJOCTET(data[2]) == 0x6F && 681 GETJOCTET(data[3]) == 0x62 && 682 GETJOCTET(data[4]) == 0x65) { 683 /* Found Adobe APP14 marker */ 684 version = (GETJOCTET(data[5]) << 8) + GETJOCTET(data[6]); 685 flags0 = (GETJOCTET(data[7]) << 8) + GETJOCTET(data[8]); 686 flags1 = (GETJOCTET(data[9]) << 8) + GETJOCTET(data[10]); 687 transform = GETJOCTET(data[11]); 688 TRACEMS4(cinfo, 1, JTRC_ADOBE, version, flags0, flags1, transform); 689 cinfo->saw_Adobe_marker = TRUE; 690 cinfo->Adobe_transform = (UINT8) transform; 691 } else { 692 /* Start of APP14 does not match "Adobe", or too short */ 693 TRACEMS1(cinfo, 1, JTRC_APP14, (int) (datalen + remaining)); 694 } 695 } 696 697 698 METHODDEF(boolean) 699 get_interesting_appn (j_decompress_ptr cinfo) 700 /* Process an APP0 or APP14 marker without saving it */ 701 { 702 INT32 length; 703 JOCTET b[APPN_DATA_LEN]; 704 unsigned int i, numtoread; 705 INPUT_VARS(cinfo); 706 707 INPUT_2BYTES(cinfo, length, return FALSE); 708 length -= 2; 709 710 /* get the interesting part of the marker data */ 711 if (length >= APPN_DATA_LEN) 712 numtoread = APPN_DATA_LEN; 713 else if (length > 0) 714 numtoread = (unsigned int) length; 715 else 716 numtoread = 0; 717 for (i = 0; i < numtoread; i++) 718 INPUT_BYTE(cinfo, b[i], return FALSE); 719 length -= numtoread; 720 721 /* process it */ 722 switch (cinfo->unread_marker) { 723 case M_APP0: 724 examine_app0(cinfo, (JOCTET FAR *) b, numtoread, length); 725 break; 726 case M_APP14: 727 examine_app14(cinfo, (JOCTET FAR *) b, numtoread, length); 728 break; 729 default: 730 /* can't get here unless jpeg_save_markers chooses wrong processor */ 731 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker); 732 break; 733 } 734 735 /* skip any remaining data -- could be lots */ 736 INPUT_SYNC(cinfo); 737 if (length > 0) 738 (*cinfo->src->skip_input_data) (cinfo, (long) length); 739 740 return TRUE; 741 } 742 743 744 #ifdef SAVE_MARKERS_SUPPORTED 745 746 METHODDEF(boolean) 747 save_marker (j_decompress_ptr cinfo) 748 /* Save an APPn or COM marker into the marker list */ 749 { 750 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 751 jpeg_saved_marker_ptr cur_marker = marker->cur_marker; 752 unsigned int bytes_read, data_length; 753 JOCTET FAR * data; 754 INT32 length = 0; 755 INPUT_VARS(cinfo); 756 757 if (cur_marker == NULL) { 758 /* begin reading a marker */ 759 INPUT_2BYTES(cinfo, length, return FALSE); 760 length -= 2; 761 if (length >= 0) { /* watch out for bogus length word */ 762 /* figure out how much we want to save */ 763 unsigned int limit; 764 if (cinfo->unread_marker == (int) M_COM) 765 limit = marker->length_limit_COM; 766 else 767 limit = marker->length_limit_APPn[cinfo->unread_marker - (int) M_APP0]; 768 if ((unsigned int) length < limit) 769 limit = (unsigned int) length; 770 /* allocate and initialize the marker item */ 771 cur_marker = (jpeg_saved_marker_ptr) 772 (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE, 773 SIZEOF(struct jpeg_marker_struct) + limit); 774 cur_marker->next = NULL; 775 cur_marker->marker = (UINT8) cinfo->unread_marker; 776 cur_marker->original_length = (unsigned int) length; 777 cur_marker->data_length = limit; 778 /* data area is just beyond the jpeg_marker_struct */ 779 data = cur_marker->data = (JOCTET FAR *) (cur_marker + 1); 780 marker->cur_marker = cur_marker; 781 marker->bytes_read = 0; 782 bytes_read = 0; 783 data_length = limit; 784 } else { 785 /* deal with bogus length word */ 786 bytes_read = data_length = 0; 787 data = NULL; 788 } 789 } else { 790 /* resume reading a marker */ 791 bytes_read = marker->bytes_read; 792 data_length = cur_marker->data_length; 793 data = cur_marker->data + bytes_read; 794 } 795 796 while (bytes_read < data_length) { 797 INPUT_SYNC(cinfo); /* move the restart point to here */ 798 marker->bytes_read = bytes_read; 799 /* If there's not at least one byte in buffer, suspend */ 800 MAKE_BYTE_AVAIL(cinfo, return FALSE); 801 /* Copy bytes with reasonable rapidity */ 802 while (bytes_read < data_length && bytes_in_buffer > 0) { 803 *data++ = *next_input_byte++; 804 bytes_in_buffer--; 805 bytes_read++; 806 } 807 } 808 809 /* Done reading what we want to read */ 810 if (cur_marker != NULL) { /* will be NULL if bogus length word */ 811 /* Add new marker to end of list */ 812 if (cinfo->marker_list == NULL) { 813 cinfo->marker_list = cur_marker; 814 } else { 815 jpeg_saved_marker_ptr prev = cinfo->marker_list; 816 while (prev->next != NULL) 817 prev = prev->next; 818 prev->next = cur_marker; 819 } 820 /* Reset pointer & calc remaining data length */ 821 data = cur_marker->data; 822 length = cur_marker->original_length - data_length; 823 } 824 /* Reset to initial state for next marker */ 825 marker->cur_marker = NULL; 826 827 /* Process the marker if interesting; else just make a generic trace msg */ 828 switch (cinfo->unread_marker) { 829 case M_APP0: 830 examine_app0(cinfo, data, data_length, length); 831 break; 832 case M_APP14: 833 examine_app14(cinfo, data, data_length, length); 834 break; 835 default: 836 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, 837 (int) (data_length + length)); 838 break; 839 } 840 841 /* skip any remaining data -- could be lots */ 842 INPUT_SYNC(cinfo); /* do before skip_input_data */ 843 if (length > 0) 844 (*cinfo->src->skip_input_data) (cinfo, (long) length); 845 846 return TRUE; 847 } 848 849 #endif /* SAVE_MARKERS_SUPPORTED */ 850 851 852 METHODDEF(boolean) 853 skip_variable (j_decompress_ptr cinfo) 854 /* Skip over an unknown or uninteresting variable-length marker */ 855 { 856 INT32 length; 857 INPUT_VARS(cinfo); 858 859 INPUT_2BYTES(cinfo, length, return FALSE); 860 length -= 2; 861 862 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, (int) length); 863 864 INPUT_SYNC(cinfo); /* do before skip_input_data */ 865 if (length > 0) 866 (*cinfo->src->skip_input_data) (cinfo, (long) length); 867 868 return TRUE; 869 } 870 871 872 /* 873 * Find the next JPEG marker, save it in cinfo->unread_marker. 874 * Returns FALSE if had to suspend before reaching a marker; 875 * in that case cinfo->unread_marker is unchanged. 876 * 877 * Note that the result might not be a valid marker code, 878 * but it will never be 0 or FF. 879 */ 880 881 LOCAL(boolean) 882 next_marker (j_decompress_ptr cinfo) 883 { 884 int c; 885 INPUT_VARS(cinfo); 886 887 for (;;) { 888 INPUT_BYTE(cinfo, c, return FALSE); 889 /* Skip any non-FF bytes. 890 * This may look a bit inefficient, but it will not occur in a valid file. 891 * We sync after each discarded byte so that a suspending data source 892 * can discard the byte from its buffer. 893 */ 894 while (c != 0xFF) { 895 cinfo->marker->discarded_bytes++; 896 INPUT_SYNC(cinfo); 897 INPUT_BYTE(cinfo, c, return FALSE); 898 } 899 /* This loop swallows any duplicate FF bytes. Extra FFs are legal as 900 * pad bytes, so don't count them in discarded_bytes. We assume there 901 * will not be so many consecutive FF bytes as to overflow a suspending 902 * data source's input buffer. 903 */ 904 do { 905 INPUT_BYTE(cinfo, c, return FALSE); 906 } while (c == 0xFF); 907 if (c != 0) 908 break; /* found a valid marker, exit loop */ 909 /* Reach here if we found a stuffed-zero data sequence (FF/00). 910 * Discard it and loop back to try again. 911 */ 912 cinfo->marker->discarded_bytes += 2; 913 INPUT_SYNC(cinfo); 914 } 915 916 if (cinfo->marker->discarded_bytes != 0) { 917 WARNMS2(cinfo, JWRN_EXTRANEOUS_DATA, cinfo->marker->discarded_bytes, c); 918 cinfo->marker->discarded_bytes = 0; 919 } 920 921 cinfo->unread_marker = c; 922 923 INPUT_SYNC(cinfo); 924 return TRUE; 925 } 926 927 928 LOCAL(boolean) 929 first_marker (j_decompress_ptr cinfo) 930 /* Like next_marker, but used to obtain the initial SOI marker. */ 931 /* For this marker, we do not allow preceding garbage or fill; otherwise, 932 * we might well scan an entire input file before realizing it ain't JPEG. 933 * If an application wants to process non-JFIF files, it must seek to the 934 * SOI before calling the JPEG library. 935 */ 936 { 937 int c, c2; 938 INPUT_VARS(cinfo); 939 940 INPUT_BYTE(cinfo, c, return FALSE); 941 INPUT_BYTE(cinfo, c2, return FALSE); 942 if (c != 0xFF || c2 != (int) M_SOI) 943 ERREXIT2(cinfo, JERR_NO_SOI, c, c2); 944 945 cinfo->unread_marker = c2; 946 947 INPUT_SYNC(cinfo); 948 return TRUE; 949 } 950 951 952 /* 953 * Read markers until SOS or EOI. 954 * 955 * Returns same codes as are defined for jpeg_consume_input: 956 * JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI. 957 */ 958 959 METHODDEF(int) 960 read_markers (j_decompress_ptr cinfo) 961 { 962 /* Outer loop repeats once for each marker. */ 963 for (;;) { 964 /* Collect the marker proper, unless we already did. */ 965 /* NB: first_marker() enforces the requirement that SOI appear first. */ 966 if (cinfo->unread_marker == 0) { 967 if (! cinfo->marker->saw_SOI) { 968 if (! first_marker(cinfo)) 969 return JPEG_SUSPENDED; 970 } else { 971 if (! next_marker(cinfo)) 972 return JPEG_SUSPENDED; 973 } 974 } 975 976 /* 977 * Save the position of the fist marker after SOF. 978 */ 979 if (cinfo->marker->current_sos_marker_position == -1) 980 cinfo->marker->current_sos_marker_position = 981 jget_input_stream_position(cinfo) - 2; 982 983 /* At this point cinfo->unread_marker contains the marker code and the 984 * input point is just past the marker proper, but before any parameters. 985 * A suspension will cause us to return with this state still true. 986 */ 987 switch (cinfo->unread_marker) { 988 case M_SOI: 989 if (! get_soi(cinfo)) 990 return JPEG_SUSPENDED; 991 break; 992 993 case M_SOF0: /* Baseline */ 994 case M_SOF1: /* Extended sequential, Huffman */ 995 if (! get_sof(cinfo, FALSE, FALSE)) 996 return JPEG_SUSPENDED; 997 break; 998 999 case M_SOF2: /* Progressive, Huffman */ 1000 cinfo->marker->current_sos_marker_position = -1; 1001 if (! get_sof(cinfo, TRUE, FALSE)) 1002 return JPEG_SUSPENDED; 1003 break; 1004 1005 case M_SOF9: /* Extended sequential, arithmetic */ 1006 if (! get_sof(cinfo, FALSE, TRUE)) 1007 return JPEG_SUSPENDED; 1008 break; 1009 1010 case M_SOF10: /* Progressive, arithmetic */ 1011 if (! get_sof(cinfo, TRUE, TRUE)) 1012 return JPEG_SUSPENDED; 1013 break; 1014 1015 /* Currently unsupported SOFn types */ 1016 case M_SOF3: /* Lossless, Huffman */ 1017 case M_SOF5: /* Differential sequential, Huffman */ 1018 case M_SOF6: /* Differential progressive, Huffman */ 1019 case M_SOF7: /* Differential lossless, Huffman */ 1020 case M_JPG: /* Reserved for JPEG extensions */ 1021 case M_SOF11: /* Lossless, arithmetic */ 1022 case M_SOF13: /* Differential sequential, arithmetic */ 1023 case M_SOF14: /* Differential progressive, arithmetic */ 1024 case M_SOF15: /* Differential lossless, arithmetic */ 1025 ERREXIT1(cinfo, JERR_SOF_UNSUPPORTED, cinfo->unread_marker); 1026 break; 1027 1028 case M_SOS: 1029 if (! get_sos(cinfo)) 1030 return JPEG_SUSPENDED; 1031 cinfo->unread_marker = 0; /* processed the marker */ 1032 return JPEG_REACHED_SOS; 1033 1034 case M_EOI: 1035 TRACEMS(cinfo, 1, JTRC_EOI); 1036 cinfo->unread_marker = 0; /* processed the marker */ 1037 return JPEG_REACHED_EOI; 1038 1039 case M_DAC: 1040 if (! get_dac(cinfo)) 1041 return JPEG_SUSPENDED; 1042 break; 1043 1044 case M_DHT: 1045 if (! get_dht(cinfo)) 1046 return JPEG_SUSPENDED; 1047 break; 1048 1049 case M_DQT: 1050 if (! get_dqt(cinfo)) 1051 return JPEG_SUSPENDED; 1052 break; 1053 1054 case M_DRI: 1055 if (! get_dri(cinfo)) 1056 return JPEG_SUSPENDED; 1057 break; 1058 1059 case M_APP0: 1060 case M_APP1: 1061 case M_APP2: 1062 case M_APP3: 1063 case M_APP4: 1064 case M_APP5: 1065 case M_APP6: 1066 case M_APP7: 1067 case M_APP8: 1068 case M_APP9: 1069 case M_APP10: 1070 case M_APP11: 1071 case M_APP12: 1072 case M_APP13: 1073 case M_APP14: 1074 case M_APP15: 1075 if (! (*((my_marker_ptr) cinfo->marker)->process_APPn[ 1076 cinfo->unread_marker - (int) M_APP0]) (cinfo)) 1077 return JPEG_SUSPENDED; 1078 break; 1079 1080 case M_COM: 1081 if (! (*((my_marker_ptr) cinfo->marker)->process_COM) (cinfo)) 1082 return JPEG_SUSPENDED; 1083 break; 1084 1085 case M_RST0: /* these are all parameterless */ 1086 case M_RST1: 1087 case M_RST2: 1088 case M_RST3: 1089 case M_RST4: 1090 case M_RST5: 1091 case M_RST6: 1092 case M_RST7: 1093 case M_TEM: 1094 TRACEMS1(cinfo, 1, JTRC_PARMLESS_MARKER, cinfo->unread_marker); 1095 break; 1096 1097 case M_DNL: /* Ignore DNL ... perhaps the wrong thing */ 1098 if (! skip_variable(cinfo)) 1099 return JPEG_SUSPENDED; 1100 break; 1101 1102 default: /* must be DHP, EXP, JPGn, or RESn */ 1103 /* For now, we treat the reserved markers as fatal errors since they are 1104 * likely to be used to signal incompatible JPEG Part 3 extensions. 1105 * Once the JPEG 3 version-number marker is well defined, this code 1106 * ought to change! 1107 */ 1108 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker); 1109 break; 1110 } 1111 /* Successfully processed marker, so reset state variable */ 1112 cinfo->unread_marker = 0; 1113 } /* end loop */ 1114 } 1115 1116 1117 /* 1118 * Read a restart marker, which is expected to appear next in the datastream; 1119 * if the marker is not there, take appropriate recovery action. 1120 * Returns FALSE if suspension is required. 1121 * 1122 * This is called by the entropy decoder after it has read an appropriate 1123 * number of MCUs. cinfo->unread_marker may be nonzero if the entropy decoder 1124 * has already read a marker from the data source. Under normal conditions 1125 * cinfo->unread_marker will be reset to 0 before returning; if not reset, 1126 * it holds a marker which the decoder will be unable to read past. 1127 */ 1128 1129 METHODDEF(boolean) 1130 read_restart_marker (j_decompress_ptr cinfo) 1131 { 1132 /* Obtain a marker unless we already did. */ 1133 /* Note that next_marker will complain if it skips any data. */ 1134 if (cinfo->unread_marker == 0) { 1135 if (! next_marker(cinfo)) 1136 return FALSE; 1137 } 1138 1139 if (cinfo->unread_marker == 1140 ((int) M_RST0 + cinfo->marker->next_restart_num)) { 1141 /* Normal case --- swallow the marker and let entropy decoder continue */ 1142 TRACEMS1(cinfo, 3, JTRC_RST, cinfo->marker->next_restart_num); 1143 cinfo->unread_marker = 0; 1144 } else { 1145 /* Uh-oh, the restart markers have been messed up. */ 1146 /* Let the data source manager determine how to resync. */ 1147 if (! (*cinfo->src->resync_to_restart) (cinfo, 1148 cinfo->marker->next_restart_num)) 1149 return FALSE; 1150 } 1151 1152 /* Update next-restart state */ 1153 cinfo->marker->next_restart_num = (cinfo->marker->next_restart_num + 1) & 7; 1154 1155 return TRUE; 1156 } 1157 1158 1159 /* 1160 * This is the default resync_to_restart method for data source managers 1161 * to use if they don't have any better approach. Some data source managers 1162 * may be able to back up, or may have additional knowledge about the data 1163 * which permits a more intelligent recovery strategy; such managers would 1164 * presumably supply their own resync method. 1165 * 1166 * read_restart_marker calls resync_to_restart if it finds a marker other than 1167 * the restart marker it was expecting. (This code is *not* used unless 1168 * a nonzero restart interval has been declared.) cinfo->unread_marker is 1169 * the marker code actually found (might be anything, except 0 or FF). 1170 * The desired restart marker number (0..7) is passed as a parameter. 1171 * This routine is supposed to apply whatever error recovery strategy seems 1172 * appropriate in order to position the input stream to the next data segment. 1173 * Note that cinfo->unread_marker is treated as a marker appearing before 1174 * the current data-source input point; usually it should be reset to zero 1175 * before returning. 1176 * Returns FALSE if suspension is required. 1177 * 1178 * This implementation is substantially constrained by wanting to treat the 1179 * input as a data stream; this means we can't back up. Therefore, we have 1180 * only the following actions to work with: 1181 * 1. Simply discard the marker and let the entropy decoder resume at next 1182 * byte of file. 1183 * 2. Read forward until we find another marker, discarding intervening 1184 * data. (In theory we could look ahead within the current bufferload, 1185 * without having to discard data if we don't find the desired marker. 1186 * This idea is not implemented here, in part because it makes behavior 1187 * dependent on buffer size and chance buffer-boundary positions.) 1188 * 3. Leave the marker unread (by failing to zero cinfo->unread_marker). 1189 * This will cause the entropy decoder to process an empty data segment, 1190 * inserting dummy zeroes, and then we will reprocess the marker. 1191 * 1192 * #2 is appropriate if we think the desired marker lies ahead, while #3 is 1193 * appropriate if the found marker is a future restart marker (indicating 1194 * that we have missed the desired restart marker, probably because it got 1195 * corrupted). 1196 * We apply #2 or #3 if the found marker is a restart marker no more than 1197 * two counts behind or ahead of the expected one. We also apply #2 if the 1198 * found marker is not a legal JPEG marker code (it's certainly bogus data). 1199 * If the found marker is a restart marker more than 2 counts away, we do #1 1200 * (too much risk that the marker is erroneous; with luck we will be able to 1201 * resync at some future point). 1202 * For any valid non-restart JPEG marker, we apply #3. This keeps us from 1203 * overrunning the end of a scan. An implementation limited to single-scan 1204 * files might find it better to apply #2 for markers other than EOI, since 1205 * any other marker would have to be bogus data in that case. 1206 */ 1207 1208 GLOBAL(boolean) 1209 jpeg_resync_to_restart (j_decompress_ptr cinfo, int desired) 1210 { 1211 int marker = cinfo->unread_marker; 1212 int action = 1; 1213 1214 /* Always put up a warning. */ 1215 WARNMS2(cinfo, JWRN_MUST_RESYNC, marker, desired); 1216 1217 /* Outer loop handles repeated decision after scanning forward. */ 1218 for (;;) { 1219 if (marker < (int) M_SOF0) 1220 action = 2; /* invalid marker */ 1221 else if (marker < (int) M_RST0 || marker > (int) M_RST7) 1222 action = 3; /* valid non-restart marker */ 1223 else { 1224 if (marker == ((int) M_RST0 + ((desired+1) & 7)) || 1225 marker == ((int) M_RST0 + ((desired+2) & 7))) 1226 action = 3; /* one of the next two expected restarts */ 1227 else if (marker == ((int) M_RST0 + ((desired-1) & 7)) || 1228 marker == ((int) M_RST0 + ((desired-2) & 7))) 1229 action = 2; /* a prior restart, so advance */ 1230 else 1231 action = 1; /* desired restart or too far away */ 1232 } 1233 TRACEMS2(cinfo, 4, JTRC_RECOVERY_ACTION, marker, action); 1234 switch (action) { 1235 case 1: 1236 /* Discard marker and let entropy decoder resume processing. */ 1237 cinfo->unread_marker = 0; 1238 return TRUE; 1239 case 2: 1240 /* Scan to the next marker, and repeat the decision loop. */ 1241 if (! next_marker(cinfo)) 1242 return FALSE; 1243 marker = cinfo->unread_marker; 1244 break; 1245 case 3: 1246 /* Return without advancing past this marker. */ 1247 /* Entropy decoder will be forced to process an empty segment. */ 1248 return TRUE; 1249 } 1250 } /* end loop */ 1251 } 1252 1253 /* 1254 * Get the position for all SOS markers in the image. 1255 */ 1256 1257 METHODDEF(void) 1258 get_sos_marker_position(j_decompress_ptr cinfo, huffman_index *index) 1259 { 1260 unsigned char *head; 1261 int count = 0; 1262 int retcode = JPEG_REACHED_SOS; 1263 1264 while (cinfo->src->bytes_in_buffer > 0) { 1265 if (retcode == JPEG_REACHED_SOS) { 1266 jpeg_configure_huffman_index_scan(cinfo, index, count++, 1267 cinfo->marker->current_sos_marker_position); 1268 // Skips scan content to the next non-RST JPEG marker. 1269 while(next_marker(cinfo) && 1270 cinfo->unread_marker >= M_RST0 && cinfo->unread_marker <= M_RST7) 1271 ; 1272 cinfo->marker->current_sos_marker_position = 1273 jget_input_stream_position(cinfo) - 2; 1274 retcode = read_markers(cinfo); 1275 } else { 1276 break; 1277 } 1278 } 1279 } 1280 1281 /* 1282 * Reset marker processing state to begin a fresh datastream. 1283 */ 1284 1285 METHODDEF(void) 1286 reset_marker_reader (j_decompress_ptr cinfo) 1287 { 1288 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 1289 1290 cinfo->comp_info = NULL; /* until allocated by get_sof */ 1291 cinfo->input_scan_number = 0; /* no SOS seen yet */ 1292 cinfo->unread_marker = 0; /* no pending marker */ 1293 marker->pub.saw_SOI = FALSE; /* set internal state too */ 1294 marker->pub.saw_SOF = FALSE; 1295 marker->pub.discarded_bytes = 0; 1296 marker->cur_marker = NULL; 1297 } 1298 1299 1300 /* 1301 * Initialize the marker reader module. 1302 * This is called only once, when the decompression object is created. 1303 */ 1304 1305 GLOBAL(void) 1306 jinit_marker_reader (j_decompress_ptr cinfo) 1307 { 1308 my_marker_ptr marker; 1309 int i; 1310 1311 /* Create subobject in permanent pool */ 1312 marker = (my_marker_ptr) 1313 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT, 1314 SIZEOF(my_marker_reader)); 1315 cinfo->marker = (struct jpeg_marker_reader *) marker; 1316 /* Initialize public method pointers */ 1317 marker->pub.reset_marker_reader = reset_marker_reader; 1318 marker->pub.read_markers = read_markers; 1319 marker->pub.read_restart_marker = read_restart_marker; 1320 marker->pub.get_sos_marker_position = get_sos_marker_position; 1321 1322 // Initialize the SOS marker position to avoid underdefined behavior due to 1323 // using a undefined field. 1324 marker->pub.current_sos_marker_position = 0; 1325 1326 /* Initialize COM/APPn processing. 1327 * By default, we examine and then discard APP0 and APP14, 1328 * but simply discard COM and all other APPn. 1329 */ 1330 marker->process_COM = skip_variable; 1331 marker->length_limit_COM = 0; 1332 for (i = 0; i < 16; i++) { 1333 marker->process_APPn[i] = skip_variable; 1334 marker->length_limit_APPn[i] = 0; 1335 } 1336 marker->process_APPn[0] = get_interesting_appn; 1337 marker->process_APPn[14] = get_interesting_appn; 1338 /* Reset marker processing state */ 1339 reset_marker_reader(cinfo); 1340 } 1341 1342 1343 /* 1344 * Control saving of COM and APPn markers into marker_list. 1345 */ 1346 1347 #ifdef SAVE_MARKERS_SUPPORTED 1348 1349 GLOBAL(void) 1350 jpeg_save_markers (j_decompress_ptr cinfo, int marker_code, 1351 unsigned int length_limit) 1352 { 1353 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 1354 long maxlength; 1355 jpeg_marker_parser_method processor; 1356 1357 /* Length limit mustn't be larger than what we can allocate 1358 * (should only be a concern in a 16-bit environment). 1359 */ 1360 maxlength = cinfo->mem->max_alloc_chunk - SIZEOF(struct jpeg_marker_struct); 1361 if (((long) length_limit) > maxlength) 1362 length_limit = (unsigned int) maxlength; 1363 1364 /* Choose processor routine to use. 1365 * APP0/APP14 have special requirements. 1366 */ 1367 if (length_limit) { 1368 processor = save_marker; 1369 /* If saving APP0/APP14, save at least enough for our internal use. */ 1370 if (marker_code == (int) M_APP0 && length_limit < APP0_DATA_LEN) 1371 length_limit = APP0_DATA_LEN; 1372 else if (marker_code == (int) M_APP14 && length_limit < APP14_DATA_LEN) 1373 length_limit = APP14_DATA_LEN; 1374 } else { 1375 processor = skip_variable; 1376 /* If discarding APP0/APP14, use our regular on-the-fly processor. */ 1377 if (marker_code == (int) M_APP0 || marker_code == (int) M_APP14) 1378 processor = get_interesting_appn; 1379 } 1380 1381 if (marker_code == (int) M_COM) { 1382 marker->process_COM = processor; 1383 marker->length_limit_COM = length_limit; 1384 } else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15) { 1385 marker->process_APPn[marker_code - (int) M_APP0] = processor; 1386 marker->length_limit_APPn[marker_code - (int) M_APP0] = length_limit; 1387 } else 1388 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code); 1389 } 1390 1391 #endif /* SAVE_MARKERS_SUPPORTED */ 1392 1393 1394 /* 1395 * Install a special processing method for COM or APPn markers. 1396 */ 1397 1398 GLOBAL(void) 1399 jpeg_set_marker_processor (j_decompress_ptr cinfo, int marker_code, 1400 jpeg_marker_parser_method routine) 1401 { 1402 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 1403 1404 if (marker_code == (int) M_COM) 1405 marker->process_COM = routine; 1406 else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15) 1407 marker->process_APPn[marker_code - (int) M_APP0] = routine; 1408 else 1409 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code); 1410 } 1411
