1 /* 2 * jdmarker.c 3 * 4 * This file was part of the Independent JPEG Group's software: 5 * Copyright (C) 1991-1998, Thomas G. Lane. 6 * libjpeg-turbo Modifications: 7 * Copyright (C) 2012, 2015, D. R. Commander. 8 * For conditions of distribution and use, see the accompanying README.ijg 9 * file. 10 * 11 * This file contains routines to decode JPEG datastream markers. 12 * Most of the complexity arises from our desire to support input 13 * suspension: if not all of the data for a marker is available, 14 * we must exit back to the application. On resumption, we reprocess 15 * the marker. 16 */ 17 18 #define JPEG_INTERNALS 19 #include "jinclude.h" 20 #include "jpeglib.h" 21 22 23 typedef enum { /* JPEG marker codes */ 24 M_SOF0 = 0xc0, 25 M_SOF1 = 0xc1, 26 M_SOF2 = 0xc2, 27 M_SOF3 = 0xc3, 28 29 M_SOF5 = 0xc5, 30 M_SOF6 = 0xc6, 31 M_SOF7 = 0xc7, 32 33 M_JPG = 0xc8, 34 M_SOF9 = 0xc9, 35 M_SOF10 = 0xca, 36 M_SOF11 = 0xcb, 37 38 M_SOF13 = 0xcd, 39 M_SOF14 = 0xce, 40 M_SOF15 = 0xcf, 41 42 M_DHT = 0xc4, 43 44 M_DAC = 0xcc, 45 46 M_RST0 = 0xd0, 47 M_RST1 = 0xd1, 48 M_RST2 = 0xd2, 49 M_RST3 = 0xd3, 50 M_RST4 = 0xd4, 51 M_RST5 = 0xd5, 52 M_RST6 = 0xd6, 53 M_RST7 = 0xd7, 54 55 M_SOI = 0xd8, 56 M_EOI = 0xd9, 57 M_SOS = 0xda, 58 M_DQT = 0xdb, 59 M_DNL = 0xdc, 60 M_DRI = 0xdd, 61 M_DHP = 0xde, 62 M_EXP = 0xdf, 63 64 M_APP0 = 0xe0, 65 M_APP1 = 0xe1, 66 M_APP2 = 0xe2, 67 M_APP3 = 0xe3, 68 M_APP4 = 0xe4, 69 M_APP5 = 0xe5, 70 M_APP6 = 0xe6, 71 M_APP7 = 0xe7, 72 M_APP8 = 0xe8, 73 M_APP9 = 0xe9, 74 M_APP10 = 0xea, 75 M_APP11 = 0xeb, 76 M_APP12 = 0xec, 77 M_APP13 = 0xed, 78 M_APP14 = 0xee, 79 M_APP15 = 0xef, 80 81 M_JPG0 = 0xf0, 82 M_JPG13 = 0xfd, 83 M_COM = 0xfe, 84 85 M_TEM = 0x01, 86 87 M_ERROR = 0x100 88 } JPEG_MARKER; 89 90 91 /* Private state */ 92 93 typedef struct { 94 struct jpeg_marker_reader pub; /* public fields */ 95 96 /* Application-overridable marker processing methods */ 97 jpeg_marker_parser_method process_COM; 98 jpeg_marker_parser_method process_APPn[16]; 99 100 /* Limit on marker data length to save for each marker type */ 101 unsigned int length_limit_COM; 102 unsigned int length_limit_APPn[16]; 103 104 /* Status of COM/APPn marker saving */ 105 jpeg_saved_marker_ptr cur_marker; /* NULL if not processing a marker */ 106 unsigned int bytes_read; /* data bytes read so far in marker */ 107 /* Note: cur_marker is not linked into marker_list until it's all read. */ 108 } my_marker_reader; 109 110 typedef my_marker_reader *my_marker_ptr; 111 112 113 /* 114 * Macros for fetching data from the data source module. 115 * 116 * At all times, cinfo->src->next_input_byte and ->bytes_in_buffer reflect 117 * the current restart point; we update them only when we have reached a 118 * suitable place to restart if a suspension occurs. 119 */ 120 121 /* Declare and initialize local copies of input pointer/count */ 122 #define INPUT_VARS(cinfo) \ 123 struct jpeg_source_mgr *datasrc = (cinfo)->src; \ 124 const JOCTET *next_input_byte = datasrc->next_input_byte; \ 125 size_t bytes_in_buffer = datasrc->bytes_in_buffer 126 127 /* Unload the local copies --- do this only at a restart boundary */ 128 #define INPUT_SYNC(cinfo) \ 129 ( datasrc->next_input_byte = next_input_byte, \ 130 datasrc->bytes_in_buffer = bytes_in_buffer ) 131 132 /* Reload the local copies --- used only in MAKE_BYTE_AVAIL */ 133 #define INPUT_RELOAD(cinfo) \ 134 ( next_input_byte = datasrc->next_input_byte, \ 135 bytes_in_buffer = datasrc->bytes_in_buffer ) 136 137 /* Internal macro for INPUT_BYTE and INPUT_2BYTES: make a byte available. 138 * Note we do *not* do INPUT_SYNC before calling fill_input_buffer, 139 * but we must reload the local copies after a successful fill. 140 */ 141 #define MAKE_BYTE_AVAIL(cinfo,action) \ 142 if (bytes_in_buffer == 0) { \ 143 if (! (*datasrc->fill_input_buffer) (cinfo)) \ 144 { action; } \ 145 INPUT_RELOAD(cinfo); \ 146 } 147 148 /* Read a byte into variable V. 149 * If must suspend, take the specified action (typically "return FALSE"). 150 */ 151 #define INPUT_BYTE(cinfo,V,action) \ 152 MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \ 153 bytes_in_buffer--; \ 154 V = GETJOCTET(*next_input_byte++); ) 155 156 /* As above, but read two bytes interpreted as an unsigned 16-bit integer. 157 * V should be declared unsigned int or perhaps JLONG. 158 */ 159 #define INPUT_2BYTES(cinfo,V,action) \ 160 MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \ 161 bytes_in_buffer--; \ 162 V = ((unsigned int) GETJOCTET(*next_input_byte++)) << 8; \ 163 MAKE_BYTE_AVAIL(cinfo,action); \ 164 bytes_in_buffer--; \ 165 V += GETJOCTET(*next_input_byte++); ) 166 167 168 /* 169 * Routines to process JPEG markers. 170 * 171 * Entry condition: JPEG marker itself has been read and its code saved 172 * in cinfo->unread_marker; input restart point is just after the marker. 173 * 174 * Exit: if return TRUE, have read and processed any parameters, and have 175 * updated the restart point to point after the parameters. 176 * If return FALSE, was forced to suspend before reaching end of 177 * marker parameters; restart point has not been moved. Same routine 178 * will be called again after application supplies more input data. 179 * 180 * This approach to suspension assumes that all of a marker's parameters 181 * can fit into a single input bufferload. This should hold for "normal" 182 * markers. Some COM/APPn markers might have large parameter segments 183 * that might not fit. If we are simply dropping such a marker, we use 184 * skip_input_data to get past it, and thereby put the problem on the 185 * source manager's shoulders. If we are saving the marker's contents 186 * into memory, we use a slightly different convention: when forced to 187 * suspend, the marker processor updates the restart point to the end of 188 * what it's consumed (ie, the end of the buffer) before returning FALSE. 189 * On resumption, cinfo->unread_marker still contains the marker code, 190 * but the data source will point to the next chunk of marker data. 191 * The marker processor must retain internal state to deal with this. 192 * 193 * Note that we don't bother to avoid duplicate trace messages if a 194 * suspension occurs within marker parameters. Other side effects 195 * require more care. 196 */ 197 198 199 LOCAL(boolean) 200 get_soi (j_decompress_ptr cinfo) 201 /* Process an SOI marker */ 202 { 203 int i; 204 205 TRACEMS(cinfo, 1, JTRC_SOI); 206 207 if (cinfo->marker->saw_SOI) 208 ERREXIT(cinfo, JERR_SOI_DUPLICATE); 209 210 /* Reset all parameters that are defined to be reset by SOI */ 211 212 for (i = 0; i < NUM_ARITH_TBLS; i++) { 213 cinfo->arith_dc_L[i] = 0; 214 cinfo->arith_dc_U[i] = 1; 215 cinfo->arith_ac_K[i] = 5; 216 } 217 cinfo->restart_interval = 0; 218 219 /* Set initial assumptions for colorspace etc */ 220 221 cinfo->jpeg_color_space = JCS_UNKNOWN; 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_prog, boolean is_arith) 241 /* Process a SOFn marker */ 242 { 243 JLONG length; 244 int c, ci; 245 jpeg_component_info *compptr; 246 INPUT_VARS(cinfo); 247 248 cinfo->progressive_mode = is_prog; 249 cinfo->arith_code = is_arith; 250 251 INPUT_2BYTES(cinfo, length, return FALSE); 252 253 INPUT_BYTE(cinfo, cinfo->data_precision, return FALSE); 254 INPUT_2BYTES(cinfo, cinfo->image_height, return FALSE); 255 INPUT_2BYTES(cinfo, cinfo->image_width, return FALSE); 256 INPUT_BYTE(cinfo, cinfo->num_components, return FALSE); 257 258 length -= 8; 259 260 TRACEMS4(cinfo, 1, JTRC_SOF, cinfo->unread_marker, 261 (int) cinfo->image_width, (int) cinfo->image_height, 262 cinfo->num_components); 263 264 if (cinfo->marker->saw_SOF) 265 ERREXIT(cinfo, JERR_SOF_DUPLICATE); 266 267 /* We don't support files in which the image height is initially specified */ 268 /* as 0 and is later redefined by DNL. As long as we have to check that, */ 269 /* might as well have a general sanity check. */ 270 if (cinfo->image_height <= 0 || cinfo->image_width <= 0 271 || cinfo->num_components <= 0) 272 ERREXIT(cinfo, JERR_EMPTY_IMAGE); 273 274 if (length != (cinfo->num_components * 3)) 275 ERREXIT(cinfo, JERR_BAD_LENGTH); 276 277 if (cinfo->comp_info == NULL) /* do only once, even if suspend */ 278 cinfo->comp_info = (jpeg_component_info *) (*cinfo->mem->alloc_small) 279 ((j_common_ptr) cinfo, JPOOL_IMAGE, 280 cinfo->num_components * sizeof(jpeg_component_info)); 281 282 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 283 ci++, compptr++) { 284 compptr->component_index = ci; 285 INPUT_BYTE(cinfo, compptr->component_id, return FALSE); 286 INPUT_BYTE(cinfo, c, return FALSE); 287 compptr->h_samp_factor = (c >> 4) & 15; 288 compptr->v_samp_factor = (c ) & 15; 289 INPUT_BYTE(cinfo, compptr->quant_tbl_no, return FALSE); 290 291 TRACEMS4(cinfo, 1, JTRC_SOF_COMPONENT, 292 compptr->component_id, compptr->h_samp_factor, 293 compptr->v_samp_factor, compptr->quant_tbl_no); 294 } 295 296 cinfo->marker->saw_SOF = TRUE; 297 298 INPUT_SYNC(cinfo); 299 return TRUE; 300 } 301 302 303 LOCAL(boolean) 304 get_sos (j_decompress_ptr cinfo) 305 /* Process a SOS marker */ 306 { 307 JLONG length; 308 int i, ci, n, c, cc, pi; 309 jpeg_component_info *compptr; 310 INPUT_VARS(cinfo); 311 312 if (! cinfo->marker->saw_SOF) 313 ERREXIT(cinfo, JERR_SOS_NO_SOF); 314 315 INPUT_2BYTES(cinfo, length, return FALSE); 316 317 INPUT_BYTE(cinfo, n, return FALSE); /* Number of components */ 318 319 TRACEMS1(cinfo, 1, JTRC_SOS, n); 320 321 if (length != (n * 2 + 6) || n < 1 || n > MAX_COMPS_IN_SCAN) 322 ERREXIT(cinfo, JERR_BAD_LENGTH); 323 324 cinfo->comps_in_scan = n; 325 326 /* Collect the component-spec parameters */ 327 328 for (i = 0; i < MAX_COMPS_IN_SCAN; i++) 329 cinfo->cur_comp_info[i] = NULL; 330 331 for (i = 0; i < n; i++) { 332 INPUT_BYTE(cinfo, cc, return FALSE); 333 INPUT_BYTE(cinfo, c, return FALSE); 334 335 for (ci = 0, compptr = cinfo->comp_info; 336 ci < cinfo->num_components && ci < MAX_COMPS_IN_SCAN; 337 ci++, compptr++) { 338 if (cc == compptr->component_id && !cinfo->cur_comp_info[ci]) 339 goto id_found; 340 } 341 342 ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc); 343 344 id_found: 345 346 cinfo->cur_comp_info[i] = compptr; 347 compptr->dc_tbl_no = (c >> 4) & 15; 348 compptr->ac_tbl_no = (c ) & 15; 349 350 TRACEMS3(cinfo, 1, JTRC_SOS_COMPONENT, cc, 351 compptr->dc_tbl_no, compptr->ac_tbl_no); 352 353 /* This CSi (cc) should differ from the previous CSi */ 354 for (pi = 0; pi < i; pi++) { 355 if (cinfo->cur_comp_info[pi] == compptr) { 356 ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc); 357 } 358 } 359 } 360 361 /* Collect the additional scan parameters Ss, Se, Ah/Al. */ 362 INPUT_BYTE(cinfo, c, return FALSE); 363 cinfo->Ss = c; 364 INPUT_BYTE(cinfo, c, return FALSE); 365 cinfo->Se = c; 366 INPUT_BYTE(cinfo, c, return FALSE); 367 cinfo->Ah = (c >> 4) & 15; 368 cinfo->Al = (c ) & 15; 369 370 TRACEMS4(cinfo, 1, JTRC_SOS_PARAMS, cinfo->Ss, cinfo->Se, 371 cinfo->Ah, cinfo->Al); 372 373 /* Prepare to scan data & restart markers */ 374 cinfo->marker->next_restart_num = 0; 375 376 /* Count another SOS marker */ 377 cinfo->input_scan_number++; 378 379 INPUT_SYNC(cinfo); 380 return TRUE; 381 } 382 383 384 #ifdef D_ARITH_CODING_SUPPORTED 385 386 LOCAL(boolean) 387 get_dac (j_decompress_ptr cinfo) 388 /* Process a DAC marker */ 389 { 390 JLONG length; 391 int index, val; 392 INPUT_VARS(cinfo); 393 394 INPUT_2BYTES(cinfo, length, return FALSE); 395 length -= 2; 396 397 while (length > 0) { 398 INPUT_BYTE(cinfo, index, return FALSE); 399 INPUT_BYTE(cinfo, val, return FALSE); 400 401 length -= 2; 402 403 TRACEMS2(cinfo, 1, JTRC_DAC, index, val); 404 405 if (index < 0 || index >= (2*NUM_ARITH_TBLS)) 406 ERREXIT1(cinfo, JERR_DAC_INDEX, index); 407 408 if (index >= NUM_ARITH_TBLS) { /* define AC table */ 409 cinfo->arith_ac_K[index-NUM_ARITH_TBLS] = (UINT8) val; 410 } else { /* define DC table */ 411 cinfo->arith_dc_L[index] = (UINT8) (val & 0x0F); 412 cinfo->arith_dc_U[index] = (UINT8) (val >> 4); 413 if (cinfo->arith_dc_L[index] > cinfo->arith_dc_U[index]) 414 ERREXIT1(cinfo, JERR_DAC_VALUE, val); 415 } 416 } 417 418 if (length != 0) 419 ERREXIT(cinfo, JERR_BAD_LENGTH); 420 421 INPUT_SYNC(cinfo); 422 return TRUE; 423 } 424 425 #else /* ! D_ARITH_CODING_SUPPORTED */ 426 427 #define get_dac(cinfo) skip_variable(cinfo) 428 429 #endif /* D_ARITH_CODING_SUPPORTED */ 430 431 432 LOCAL(boolean) 433 get_dht (j_decompress_ptr cinfo) 434 /* Process a DHT marker */ 435 { 436 JLONG length; 437 UINT8 bits[17]; 438 UINT8 huffval[256]; 439 int i, index, count; 440 JHUFF_TBL **htblptr; 441 INPUT_VARS(cinfo); 442 443 INPUT_2BYTES(cinfo, length, return FALSE); 444 length -= 2; 445 446 while (length > 16) { 447 INPUT_BYTE(cinfo, index, return FALSE); 448 449 TRACEMS1(cinfo, 1, JTRC_DHT, index); 450 451 bits[0] = 0; 452 count = 0; 453 for (i = 1; i <= 16; i++) { 454 INPUT_BYTE(cinfo, bits[i], return FALSE); 455 count += bits[i]; 456 } 457 458 length -= 1 + 16; 459 460 TRACEMS8(cinfo, 2, JTRC_HUFFBITS, 461 bits[1], bits[2], bits[3], bits[4], 462 bits[5], bits[6], bits[7], bits[8]); 463 TRACEMS8(cinfo, 2, JTRC_HUFFBITS, 464 bits[9], bits[10], bits[11], bits[12], 465 bits[13], bits[14], bits[15], bits[16]); 466 467 /* Here we just do minimal validation of the counts to avoid walking 468 * off the end of our table space. jdhuff.c will check more carefully. 469 */ 470 if (count > 256 || ((JLONG) count) > length) 471 ERREXIT(cinfo, JERR_BAD_HUFF_TABLE); 472 473 for (i = 0; i < count; i++) 474 INPUT_BYTE(cinfo, huffval[i], return FALSE); 475 476 MEMZERO(&huffval[count], (256 - count) * sizeof(UINT8)); 477 478 length -= count; 479 480 if (index & 0x10) { /* AC table definition */ 481 index -= 0x10; 482 if (index < 0 || index >= NUM_HUFF_TBLS) 483 ERREXIT1(cinfo, JERR_DHT_INDEX, index); 484 htblptr = &cinfo->ac_huff_tbl_ptrs[index]; 485 } else { /* DC table definition */ 486 if (index < 0 || index >= NUM_HUFF_TBLS) 487 ERREXIT1(cinfo, JERR_DHT_INDEX, index); 488 htblptr = &cinfo->dc_huff_tbl_ptrs[index]; 489 } 490 491 if (*htblptr == NULL) 492 *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo); 493 494 MEMCOPY((*htblptr)->bits, bits, sizeof((*htblptr)->bits)); 495 MEMCOPY((*htblptr)->huffval, huffval, sizeof((*htblptr)->huffval)); 496 } 497 498 if (length != 0) 499 ERREXIT(cinfo, JERR_BAD_LENGTH); 500 501 INPUT_SYNC(cinfo); 502 return TRUE; 503 } 504 505 506 LOCAL(boolean) 507 get_dqt (j_decompress_ptr cinfo) 508 /* Process a DQT marker */ 509 { 510 JLONG length; 511 int n, i, prec; 512 unsigned int tmp; 513 JQUANT_TBL *quant_ptr; 514 INPUT_VARS(cinfo); 515 516 INPUT_2BYTES(cinfo, length, return FALSE); 517 length -= 2; 518 519 while (length > 0) { 520 INPUT_BYTE(cinfo, n, return FALSE); 521 prec = n >> 4; 522 n &= 0x0F; 523 524 TRACEMS2(cinfo, 1, JTRC_DQT, n, prec); 525 526 if (n >= NUM_QUANT_TBLS) 527 ERREXIT1(cinfo, JERR_DQT_INDEX, n); 528 529 if (cinfo->quant_tbl_ptrs[n] == NULL) 530 cinfo->quant_tbl_ptrs[n] = jpeg_alloc_quant_table((j_common_ptr) cinfo); 531 quant_ptr = cinfo->quant_tbl_ptrs[n]; 532 533 for (i = 0; i < DCTSIZE2; i++) { 534 if (prec) 535 INPUT_2BYTES(cinfo, tmp, return FALSE); 536 else 537 INPUT_BYTE(cinfo, tmp, return FALSE); 538 /* We convert the zigzag-order table to natural array order. */ 539 quant_ptr->quantval[jpeg_natural_order[i]] = (UINT16) tmp; 540 } 541 542 if (cinfo->err->trace_level >= 2) { 543 for (i = 0; i < DCTSIZE2; i += 8) { 544 TRACEMS8(cinfo, 2, JTRC_QUANTVALS, 545 quant_ptr->quantval[i], quant_ptr->quantval[i+1], 546 quant_ptr->quantval[i+2], quant_ptr->quantval[i+3], 547 quant_ptr->quantval[i+4], quant_ptr->quantval[i+5], 548 quant_ptr->quantval[i+6], quant_ptr->quantval[i+7]); 549 } 550 } 551 552 length -= DCTSIZE2+1; 553 if (prec) length -= DCTSIZE2; 554 } 555 556 if (length != 0) 557 ERREXIT(cinfo, JERR_BAD_LENGTH); 558 559 INPUT_SYNC(cinfo); 560 return TRUE; 561 } 562 563 564 LOCAL(boolean) 565 get_dri (j_decompress_ptr cinfo) 566 /* Process a DRI marker */ 567 { 568 JLONG length; 569 unsigned int tmp; 570 INPUT_VARS(cinfo); 571 572 INPUT_2BYTES(cinfo, length, return FALSE); 573 574 if (length != 4) 575 ERREXIT(cinfo, JERR_BAD_LENGTH); 576 577 INPUT_2BYTES(cinfo, tmp, return FALSE); 578 579 TRACEMS1(cinfo, 1, JTRC_DRI, tmp); 580 581 cinfo->restart_interval = tmp; 582 583 INPUT_SYNC(cinfo); 584 return TRUE; 585 } 586 587 588 /* 589 * Routines for processing APPn and COM markers. 590 * These are either saved in memory or discarded, per application request. 591 * APP0 and APP14 are specially checked to see if they are 592 * JFIF and Adobe markers, respectively. 593 */ 594 595 #define APP0_DATA_LEN 14 /* Length of interesting data in APP0 */ 596 #define APP14_DATA_LEN 12 /* Length of interesting data in APP14 */ 597 #define APPN_DATA_LEN 14 /* Must be the largest of the above!! */ 598 599 600 LOCAL(void) 601 examine_app0 (j_decompress_ptr cinfo, JOCTET *data, 602 unsigned int datalen, JLONG remaining) 603 /* Examine first few bytes from an APP0. 604 * Take appropriate action if it is a JFIF marker. 605 * datalen is # of bytes at data[], remaining is length of rest of marker data. 606 */ 607 { 608 JLONG totallen = (JLONG) datalen + remaining; 609 610 if (datalen >= APP0_DATA_LEN && 611 GETJOCTET(data[0]) == 0x4A && 612 GETJOCTET(data[1]) == 0x46 && 613 GETJOCTET(data[2]) == 0x49 && 614 GETJOCTET(data[3]) == 0x46 && 615 GETJOCTET(data[4]) == 0) { 616 /* Found JFIF APP0 marker: save info */ 617 cinfo->saw_JFIF_marker = TRUE; 618 cinfo->JFIF_major_version = GETJOCTET(data[5]); 619 cinfo->JFIF_minor_version = GETJOCTET(data[6]); 620 cinfo->density_unit = GETJOCTET(data[7]); 621 cinfo->X_density = (GETJOCTET(data[8]) << 8) + GETJOCTET(data[9]); 622 cinfo->Y_density = (GETJOCTET(data[10]) << 8) + GETJOCTET(data[11]); 623 /* Check version. 624 * Major version must be 1, anything else signals an incompatible change. 625 * (We used to treat this as an error, but now it's a nonfatal warning, 626 * because some bozo at Hijaak couldn't read the spec.) 627 * Minor version should be 0..2, but process anyway if newer. 628 */ 629 if (cinfo->JFIF_major_version != 1) 630 WARNMS2(cinfo, JWRN_JFIF_MAJOR, 631 cinfo->JFIF_major_version, cinfo->JFIF_minor_version); 632 /* Generate trace messages */ 633 TRACEMS5(cinfo, 1, JTRC_JFIF, 634 cinfo->JFIF_major_version, cinfo->JFIF_minor_version, 635 cinfo->X_density, cinfo->Y_density, cinfo->density_unit); 636 /* Validate thumbnail dimensions and issue appropriate messages */ 637 if (GETJOCTET(data[12]) | GETJOCTET(data[13])) 638 TRACEMS2(cinfo, 1, JTRC_JFIF_THUMBNAIL, 639 GETJOCTET(data[12]), GETJOCTET(data[13])); 640 totallen -= APP0_DATA_LEN; 641 if (totallen != 642 ((JLONG)GETJOCTET(data[12]) * (JLONG)GETJOCTET(data[13]) * (JLONG) 3)) 643 TRACEMS1(cinfo, 1, JTRC_JFIF_BADTHUMBNAILSIZE, (int) totallen); 644 } else if (datalen >= 6 && 645 GETJOCTET(data[0]) == 0x4A && 646 GETJOCTET(data[1]) == 0x46 && 647 GETJOCTET(data[2]) == 0x58 && 648 GETJOCTET(data[3]) == 0x58 && 649 GETJOCTET(data[4]) == 0) { 650 /* Found JFIF "JFXX" extension APP0 marker */ 651 /* The library doesn't actually do anything with these, 652 * but we try to produce a helpful trace message. 653 */ 654 switch (GETJOCTET(data[5])) { 655 case 0x10: 656 TRACEMS1(cinfo, 1, JTRC_THUMB_JPEG, (int) totallen); 657 break; 658 case 0x11: 659 TRACEMS1(cinfo, 1, JTRC_THUMB_PALETTE, (int) totallen); 660 break; 661 case 0x13: 662 TRACEMS1(cinfo, 1, JTRC_THUMB_RGB, (int) totallen); 663 break; 664 default: 665 TRACEMS2(cinfo, 1, JTRC_JFIF_EXTENSION, 666 GETJOCTET(data[5]), (int) totallen); 667 break; 668 } 669 } else { 670 /* Start of APP0 does not match "JFIF" or "JFXX", or too short */ 671 TRACEMS1(cinfo, 1, JTRC_APP0, (int) totallen); 672 } 673 } 674 675 676 LOCAL(void) 677 examine_app14 (j_decompress_ptr cinfo, JOCTET *data, 678 unsigned int datalen, JLONG remaining) 679 /* Examine first few bytes from an APP14. 680 * Take appropriate action if it is an Adobe marker. 681 * datalen is # of bytes at data[], remaining is length of rest of marker data. 682 */ 683 { 684 unsigned int version, flags0, flags1, transform; 685 686 if (datalen >= APP14_DATA_LEN && 687 GETJOCTET(data[0]) == 0x41 && 688 GETJOCTET(data[1]) == 0x64 && 689 GETJOCTET(data[2]) == 0x6F && 690 GETJOCTET(data[3]) == 0x62 && 691 GETJOCTET(data[4]) == 0x65) { 692 /* Found Adobe APP14 marker */ 693 version = (GETJOCTET(data[5]) << 8) + GETJOCTET(data[6]); 694 flags0 = (GETJOCTET(data[7]) << 8) + GETJOCTET(data[8]); 695 flags1 = (GETJOCTET(data[9]) << 8) + GETJOCTET(data[10]); 696 transform = GETJOCTET(data[11]); 697 TRACEMS4(cinfo, 1, JTRC_ADOBE, version, flags0, flags1, transform); 698 cinfo->saw_Adobe_marker = TRUE; 699 cinfo->Adobe_transform = (UINT8) transform; 700 } else { 701 /* Start of APP14 does not match "Adobe", or too short */ 702 TRACEMS1(cinfo, 1, JTRC_APP14, (int) (datalen + remaining)); 703 } 704 } 705 706 707 METHODDEF(boolean) 708 get_interesting_appn (j_decompress_ptr cinfo) 709 /* Process an APP0 or APP14 marker without saving it */ 710 { 711 JLONG length; 712 JOCTET b[APPN_DATA_LEN]; 713 unsigned int i, numtoread; 714 INPUT_VARS(cinfo); 715 716 INPUT_2BYTES(cinfo, length, return FALSE); 717 length -= 2; 718 719 /* get the interesting part of the marker data */ 720 if (length >= APPN_DATA_LEN) 721 numtoread = APPN_DATA_LEN; 722 else if (length > 0) 723 numtoread = (unsigned int) length; 724 else 725 numtoread = 0; 726 for (i = 0; i < numtoread; i++) 727 INPUT_BYTE(cinfo, b[i], return FALSE); 728 length -= numtoread; 729 730 /* process it */ 731 switch (cinfo->unread_marker) { 732 case M_APP0: 733 examine_app0(cinfo, (JOCTET *) b, numtoread, length); 734 break; 735 case M_APP14: 736 examine_app14(cinfo, (JOCTET *) b, numtoread, length); 737 break; 738 default: 739 /* can't get here unless jpeg_save_markers chooses wrong processor */ 740 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker); 741 break; 742 } 743 744 /* skip any remaining data -- could be lots */ 745 INPUT_SYNC(cinfo); 746 if (length > 0) 747 (*cinfo->src->skip_input_data) (cinfo, (long) length); 748 749 return TRUE; 750 } 751 752 753 #ifdef SAVE_MARKERS_SUPPORTED 754 755 METHODDEF(boolean) 756 save_marker (j_decompress_ptr cinfo) 757 /* Save an APPn or COM marker into the marker list */ 758 { 759 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 760 jpeg_saved_marker_ptr cur_marker = marker->cur_marker; 761 unsigned int bytes_read, data_length; 762 JOCTET *data; 763 JLONG length = 0; 764 INPUT_VARS(cinfo); 765 766 if (cur_marker == NULL) { 767 /* begin reading a marker */ 768 INPUT_2BYTES(cinfo, length, return FALSE); 769 length -= 2; 770 if (length >= 0) { /* watch out for bogus length word */ 771 /* figure out how much we want to save */ 772 unsigned int limit; 773 if (cinfo->unread_marker == (int) M_COM) 774 limit = marker->length_limit_COM; 775 else 776 limit = marker->length_limit_APPn[cinfo->unread_marker - (int) M_APP0]; 777 if ((unsigned int) length < limit) 778 limit = (unsigned int) length; 779 /* allocate and initialize the marker item */ 780 cur_marker = (jpeg_saved_marker_ptr) 781 (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE, 782 sizeof(struct jpeg_marker_struct) + limit); 783 cur_marker->next = NULL; 784 cur_marker->marker = (UINT8) cinfo->unread_marker; 785 cur_marker->original_length = (unsigned int) length; 786 cur_marker->data_length = limit; 787 /* data area is just beyond the jpeg_marker_struct */ 788 data = cur_marker->data = (JOCTET *) (cur_marker + 1); 789 marker->cur_marker = cur_marker; 790 marker->bytes_read = 0; 791 bytes_read = 0; 792 data_length = limit; 793 } else { 794 /* deal with bogus length word */ 795 bytes_read = data_length = 0; 796 data = NULL; 797 } 798 } else { 799 /* resume reading a marker */ 800 bytes_read = marker->bytes_read; 801 data_length = cur_marker->data_length; 802 data = cur_marker->data + bytes_read; 803 } 804 805 while (bytes_read < data_length) { 806 INPUT_SYNC(cinfo); /* move the restart point to here */ 807 marker->bytes_read = bytes_read; 808 /* If there's not at least one byte in buffer, suspend */ 809 MAKE_BYTE_AVAIL(cinfo, return FALSE); 810 /* Copy bytes with reasonable rapidity */ 811 while (bytes_read < data_length && bytes_in_buffer > 0) { 812 *data++ = *next_input_byte++; 813 bytes_in_buffer--; 814 bytes_read++; 815 } 816 } 817 818 /* Done reading what we want to read */ 819 if (cur_marker != NULL) { /* will be NULL if bogus length word */ 820 /* Add new marker to end of list */ 821 if (cinfo->marker_list == NULL) { 822 cinfo->marker_list = cur_marker; 823 } else { 824 jpeg_saved_marker_ptr prev = cinfo->marker_list; 825 while (prev->next != NULL) 826 prev = prev->next; 827 prev->next = cur_marker; 828 } 829 /* Reset pointer & calc remaining data length */ 830 data = cur_marker->data; 831 length = cur_marker->original_length - data_length; 832 } 833 /* Reset to initial state for next marker */ 834 marker->cur_marker = NULL; 835 836 /* Process the marker if interesting; else just make a generic trace msg */ 837 switch (cinfo->unread_marker) { 838 case M_APP0: 839 examine_app0(cinfo, data, data_length, length); 840 break; 841 case M_APP14: 842 examine_app14(cinfo, data, data_length, length); 843 break; 844 default: 845 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, 846 (int) (data_length + length)); 847 break; 848 } 849 850 /* skip any remaining data -- could be lots */ 851 INPUT_SYNC(cinfo); /* do before skip_input_data */ 852 if (length > 0) 853 (*cinfo->src->skip_input_data) (cinfo, (long) length); 854 855 return TRUE; 856 } 857 858 #endif /* SAVE_MARKERS_SUPPORTED */ 859 860 861 METHODDEF(boolean) 862 skip_variable (j_decompress_ptr cinfo) 863 /* Skip over an unknown or uninteresting variable-length marker */ 864 { 865 JLONG length; 866 INPUT_VARS(cinfo); 867 868 INPUT_2BYTES(cinfo, length, return FALSE); 869 length -= 2; 870 871 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, (int) length); 872 873 INPUT_SYNC(cinfo); /* do before skip_input_data */ 874 if (length > 0) 875 (*cinfo->src->skip_input_data) (cinfo, (long) length); 876 877 return TRUE; 878 } 879 880 881 /* 882 * Find the next JPEG marker, save it in cinfo->unread_marker. 883 * Returns FALSE if had to suspend before reaching a marker; 884 * in that case cinfo->unread_marker is unchanged. 885 * 886 * Note that the result might not be a valid marker code, 887 * but it will never be 0 or FF. 888 */ 889 890 LOCAL(boolean) 891 next_marker (j_decompress_ptr cinfo) 892 { 893 int c; 894 INPUT_VARS(cinfo); 895 896 for (;;) { 897 INPUT_BYTE(cinfo, c, return FALSE); 898 /* Skip any non-FF bytes. 899 * This may look a bit inefficient, but it will not occur in a valid file. 900 * We sync after each discarded byte so that a suspending data source 901 * can discard the byte from its buffer. 902 */ 903 while (c != 0xFF) { 904 cinfo->marker->discarded_bytes++; 905 INPUT_SYNC(cinfo); 906 INPUT_BYTE(cinfo, c, return FALSE); 907 } 908 /* This loop swallows any duplicate FF bytes. Extra FFs are legal as 909 * pad bytes, so don't count them in discarded_bytes. We assume there 910 * will not be so many consecutive FF bytes as to overflow a suspending 911 * data source's input buffer. 912 */ 913 do { 914 INPUT_BYTE(cinfo, c, return FALSE); 915 } while (c == 0xFF); 916 if (c != 0) 917 break; /* found a valid marker, exit loop */ 918 /* Reach here if we found a stuffed-zero data sequence (FF/00). 919 * Discard it and loop back to try again. 920 */ 921 cinfo->marker->discarded_bytes += 2; 922 INPUT_SYNC(cinfo); 923 } 924 925 if (cinfo->marker->discarded_bytes != 0) { 926 WARNMS2(cinfo, JWRN_EXTRANEOUS_DATA, cinfo->marker->discarded_bytes, c); 927 cinfo->marker->discarded_bytes = 0; 928 } 929 930 cinfo->unread_marker = c; 931 932 INPUT_SYNC(cinfo); 933 return TRUE; 934 } 935 936 937 LOCAL(boolean) 938 first_marker (j_decompress_ptr cinfo) 939 /* Like next_marker, but used to obtain the initial SOI marker. */ 940 /* For this marker, we do not allow preceding garbage or fill; otherwise, 941 * we might well scan an entire input file before realizing it ain't JPEG. 942 * If an application wants to process non-JFIF files, it must seek to the 943 * SOI before calling the JPEG library. 944 */ 945 { 946 int c, c2; 947 INPUT_VARS(cinfo); 948 949 INPUT_BYTE(cinfo, c, return FALSE); 950 INPUT_BYTE(cinfo, c2, return FALSE); 951 if (c != 0xFF || c2 != (int) M_SOI) 952 ERREXIT2(cinfo, JERR_NO_SOI, c, c2); 953 954 cinfo->unread_marker = c2; 955 956 INPUT_SYNC(cinfo); 957 return TRUE; 958 } 959 960 961 /* 962 * Read markers until SOS or EOI. 963 * 964 * Returns same codes as are defined for jpeg_consume_input: 965 * JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI. 966 */ 967 968 METHODDEF(int) 969 read_markers (j_decompress_ptr cinfo) 970 { 971 /* Outer loop repeats once for each marker. */ 972 for (;;) { 973 /* Collect the marker proper, unless we already did. */ 974 /* NB: first_marker() enforces the requirement that SOI appear first. */ 975 if (cinfo->unread_marker == 0) { 976 if (! cinfo->marker->saw_SOI) { 977 if (! first_marker(cinfo)) 978 return JPEG_SUSPENDED; 979 } else { 980 if (! next_marker(cinfo)) 981 return JPEG_SUSPENDED; 982 } 983 } 984 /* At this point cinfo->unread_marker contains the marker code and the 985 * input point is just past the marker proper, but before any parameters. 986 * A suspension will cause us to return with this state still true. 987 */ 988 switch (cinfo->unread_marker) { 989 case M_SOI: 990 if (! get_soi(cinfo)) 991 return JPEG_SUSPENDED; 992 break; 993 994 case M_SOF0: /* Baseline */ 995 case M_SOF1: /* Extended sequential, Huffman */ 996 if (! get_sof(cinfo, FALSE, FALSE)) 997 return JPEG_SUSPENDED; 998 break; 999 1000 case M_SOF2: /* Progressive, Huffman */ 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 /* 1255 * Reset marker processing state to begin a fresh datastream. 1256 */ 1257 1258 METHODDEF(void) 1259 reset_marker_reader (j_decompress_ptr cinfo) 1260 { 1261 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 1262 1263 cinfo->comp_info = NULL; /* until allocated by get_sof */ 1264 cinfo->input_scan_number = 0; /* no SOS seen yet */ 1265 cinfo->unread_marker = 0; /* no pending marker */ 1266 marker->pub.saw_SOI = FALSE; /* set internal state too */ 1267 marker->pub.saw_SOF = FALSE; 1268 marker->pub.discarded_bytes = 0; 1269 marker->cur_marker = NULL; 1270 } 1271 1272 1273 /* 1274 * Initialize the marker reader module. 1275 * This is called only once, when the decompression object is created. 1276 */ 1277 1278 GLOBAL(void) 1279 jinit_marker_reader (j_decompress_ptr cinfo) 1280 { 1281 my_marker_ptr marker; 1282 int i; 1283 1284 /* Create subobject in permanent pool */ 1285 marker = (my_marker_ptr) 1286 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT, 1287 sizeof(my_marker_reader)); 1288 cinfo->marker = (struct jpeg_marker_reader *) marker; 1289 /* Initialize public method pointers */ 1290 marker->pub.reset_marker_reader = reset_marker_reader; 1291 marker->pub.read_markers = read_markers; 1292 marker->pub.read_restart_marker = read_restart_marker; 1293 /* Initialize COM/APPn processing. 1294 * By default, we examine and then discard APP0 and APP14, 1295 * but simply discard COM and all other APPn. 1296 */ 1297 marker->process_COM = skip_variable; 1298 marker->length_limit_COM = 0; 1299 for (i = 0; i < 16; i++) { 1300 marker->process_APPn[i] = skip_variable; 1301 marker->length_limit_APPn[i] = 0; 1302 } 1303 marker->process_APPn[0] = get_interesting_appn; 1304 marker->process_APPn[14] = get_interesting_appn; 1305 /* Reset marker processing state */ 1306 reset_marker_reader(cinfo); 1307 } 1308 1309 1310 /* 1311 * Control saving of COM and APPn markers into marker_list. 1312 */ 1313 1314 #ifdef SAVE_MARKERS_SUPPORTED 1315 1316 GLOBAL(void) 1317 jpeg_save_markers (j_decompress_ptr cinfo, int marker_code, 1318 unsigned int length_limit) 1319 { 1320 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 1321 long maxlength; 1322 jpeg_marker_parser_method processor; 1323 1324 /* Length limit mustn't be larger than what we can allocate 1325 * (should only be a concern in a 16-bit environment). 1326 */ 1327 maxlength = cinfo->mem->max_alloc_chunk - sizeof(struct jpeg_marker_struct); 1328 if (((long) length_limit) > maxlength) 1329 length_limit = (unsigned int) maxlength; 1330 1331 /* Choose processor routine to use. 1332 * APP0/APP14 have special requirements. 1333 */ 1334 if (length_limit) { 1335 processor = save_marker; 1336 /* If saving APP0/APP14, save at least enough for our internal use. */ 1337 if (marker_code == (int) M_APP0 && length_limit < APP0_DATA_LEN) 1338 length_limit = APP0_DATA_LEN; 1339 else if (marker_code == (int) M_APP14 && length_limit < APP14_DATA_LEN) 1340 length_limit = APP14_DATA_LEN; 1341 } else { 1342 processor = skip_variable; 1343 /* If discarding APP0/APP14, use our regular on-the-fly processor. */ 1344 if (marker_code == (int) M_APP0 || marker_code == (int) M_APP14) 1345 processor = get_interesting_appn; 1346 } 1347 1348 if (marker_code == (int) M_COM) { 1349 marker->process_COM = processor; 1350 marker->length_limit_COM = length_limit; 1351 } else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15) { 1352 marker->process_APPn[marker_code - (int) M_APP0] = processor; 1353 marker->length_limit_APPn[marker_code - (int) M_APP0] = length_limit; 1354 } else 1355 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code); 1356 } 1357 1358 #endif /* SAVE_MARKERS_SUPPORTED */ 1359 1360 1361 /* 1362 * Install a special processing method for COM or APPn markers. 1363 */ 1364 1365 GLOBAL(void) 1366 jpeg_set_marker_processor (j_decompress_ptr cinfo, int marker_code, 1367 jpeg_marker_parser_method routine) 1368 { 1369 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 1370 1371 if (marker_code == (int) M_COM) 1372 marker->process_COM = routine; 1373 else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15) 1374 marker->process_APPn[marker_code - (int) M_APP0] = routine; 1375 else 1376 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code); 1377 } 1378
