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