1 /* 2 * jcmarker.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 write JPEG datastream markers. 9 */ 10 11 #define JPEG_INTERNALS 12 #include "jinclude.h" 13 #include "jpeglib.h" 14 15 16 typedef enum { /* JPEG marker codes */ 17 M_SOF0 = 0xc0, 18 M_SOF1 = 0xc1, 19 M_SOF2 = 0xc2, 20 M_SOF3 = 0xc3, 21 22 M_SOF5 = 0xc5, 23 M_SOF6 = 0xc6, 24 M_SOF7 = 0xc7, 25 26 M_JPG = 0xc8, 27 M_SOF9 = 0xc9, 28 M_SOF10 = 0xca, 29 M_SOF11 = 0xcb, 30 31 M_SOF13 = 0xcd, 32 M_SOF14 = 0xce, 33 M_SOF15 = 0xcf, 34 35 M_DHT = 0xc4, 36 37 M_DAC = 0xcc, 38 39 M_RST0 = 0xd0, 40 M_RST1 = 0xd1, 41 M_RST2 = 0xd2, 42 M_RST3 = 0xd3, 43 M_RST4 = 0xd4, 44 M_RST5 = 0xd5, 45 M_RST6 = 0xd6, 46 M_RST7 = 0xd7, 47 48 M_SOI = 0xd8, 49 M_EOI = 0xd9, 50 M_SOS = 0xda, 51 M_DQT = 0xdb, 52 M_DNL = 0xdc, 53 M_DRI = 0xdd, 54 M_DHP = 0xde, 55 M_EXP = 0xdf, 56 57 M_APP0 = 0xe0, 58 M_APP1 = 0xe1, 59 M_APP2 = 0xe2, 60 M_APP3 = 0xe3, 61 M_APP4 = 0xe4, 62 M_APP5 = 0xe5, 63 M_APP6 = 0xe6, 64 M_APP7 = 0xe7, 65 M_APP8 = 0xe8, 66 M_APP9 = 0xe9, 67 M_APP10 = 0xea, 68 M_APP11 = 0xeb, 69 M_APP12 = 0xec, 70 M_APP13 = 0xed, 71 M_APP14 = 0xee, 72 M_APP15 = 0xef, 73 74 M_JPG0 = 0xf0, 75 M_JPG13 = 0xfd, 76 M_COM = 0xfe, 77 78 M_TEM = 0x01, 79 80 M_ERROR = 0x100 81 } JPEG_MARKER; 82 83 84 /* Private state */ 85 86 typedef struct { 87 struct jpeg_marker_writer pub; /* public fields */ 88 89 unsigned int last_restart_interval; /* last DRI value emitted; 0 after SOI */ 90 } my_marker_writer; 91 92 typedef my_marker_writer * my_marker_ptr; 93 94 95 /* 96 * Basic output routines. 97 * 98 * Note that we do not support suspension while writing a marker. 99 * Therefore, an application using suspension must ensure that there is 100 * enough buffer space for the initial markers (typ. 600-700 bytes) before 101 * calling jpeg_start_compress, and enough space to write the trailing EOI 102 * (a few bytes) before calling jpeg_finish_compress. Multipass compression 103 * modes are not supported at all with suspension, so those two are the only 104 * points where markers will be written. 105 */ 106 107 LOCAL(void) 108 emit_byte (j_compress_ptr cinfo, int val) 109 /* Emit a byte */ 110 { 111 struct jpeg_destination_mgr * dest = cinfo->dest; 112 113 *(dest->next_output_byte)++ = (JOCTET) val; 114 if (--dest->free_in_buffer == 0) { 115 if (! (*dest->empty_output_buffer) (cinfo)) 116 ERREXIT(cinfo, JERR_CANT_SUSPEND); 117 } 118 } 119 120 121 LOCAL(void) 122 emit_marker (j_compress_ptr cinfo, JPEG_MARKER mark) 123 /* Emit a marker code */ 124 { 125 emit_byte(cinfo, 0xFF); 126 emit_byte(cinfo, (int) mark); 127 } 128 129 130 LOCAL(void) 131 emit_2bytes (j_compress_ptr cinfo, int value) 132 /* Emit a 2-byte integer; these are always MSB first in JPEG files */ 133 { 134 emit_byte(cinfo, (value >> 8) & 0xFF); 135 emit_byte(cinfo, value & 0xFF); 136 } 137 138 139 /* 140 * Routines to write specific marker types. 141 */ 142 143 LOCAL(int) 144 emit_dqt (j_compress_ptr cinfo, int index) 145 /* Emit a DQT marker */ 146 /* Returns the precision used (0 = 8bits, 1 = 16bits) for baseline checking */ 147 { 148 JQUANT_TBL * qtbl = cinfo->quant_tbl_ptrs[index]; 149 int prec; 150 int i; 151 152 if (qtbl == NULL) 153 ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, index); 154 155 prec = 0; 156 for (i = 0; i < DCTSIZE2; i++) { 157 if (qtbl->quantval[i] > 255) 158 prec = 1; 159 } 160 161 if (! qtbl->sent_table) { 162 emit_marker(cinfo, M_DQT); 163 164 emit_2bytes(cinfo, prec ? DCTSIZE2*2 + 1 + 2 : DCTSIZE2 + 1 + 2); 165 166 emit_byte(cinfo, index + (prec<<4)); 167 168 for (i = 0; i < DCTSIZE2; i++) { 169 /* The table entries must be emitted in zigzag order. */ 170 unsigned int qval = qtbl->quantval[jpeg_natural_order[i]]; 171 if (prec) 172 emit_byte(cinfo, (int) (qval >> 8)); 173 emit_byte(cinfo, (int) (qval & 0xFF)); 174 } 175 176 qtbl->sent_table = TRUE; 177 } 178 179 return prec; 180 } 181 182 183 LOCAL(void) 184 emit_dht (j_compress_ptr cinfo, int index, boolean is_ac) 185 /* Emit a DHT marker */ 186 { 187 JHUFF_TBL * htbl; 188 int length, i; 189 190 if (is_ac) { 191 htbl = cinfo->ac_huff_tbl_ptrs[index]; 192 index += 0x10; /* output index has AC bit set */ 193 } else { 194 htbl = cinfo->dc_huff_tbl_ptrs[index]; 195 } 196 197 if (htbl == NULL) 198 ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, index); 199 200 if (! htbl->sent_table) { 201 emit_marker(cinfo, M_DHT); 202 203 length = 0; 204 for (i = 1; i <= 16; i++) 205 length += htbl->bits[i]; 206 207 emit_2bytes(cinfo, length + 2 + 1 + 16); 208 emit_byte(cinfo, index); 209 210 for (i = 1; i <= 16; i++) 211 emit_byte(cinfo, htbl->bits[i]); 212 213 for (i = 0; i < length; i++) 214 emit_byte(cinfo, htbl->huffval[i]); 215 216 htbl->sent_table = TRUE; 217 } 218 } 219 220 221 LOCAL(void) 222 emit_dac (j_compress_ptr cinfo) 223 /* Emit a DAC marker */ 224 /* Since the useful info is so small, we want to emit all the tables in */ 225 /* one DAC marker. Therefore this routine does its own scan of the table. */ 226 { 227 #ifdef C_ARITH_CODING_SUPPORTED 228 char dc_in_use[NUM_ARITH_TBLS]; 229 char ac_in_use[NUM_ARITH_TBLS]; 230 int length, i; 231 jpeg_component_info *compptr; 232 233 for (i = 0; i < NUM_ARITH_TBLS; i++) 234 dc_in_use[i] = ac_in_use[i] = 0; 235 236 for (i = 0; i < cinfo->comps_in_scan; i++) { 237 compptr = cinfo->cur_comp_info[i]; 238 dc_in_use[compptr->dc_tbl_no] = 1; 239 ac_in_use[compptr->ac_tbl_no] = 1; 240 } 241 242 length = 0; 243 for (i = 0; i < NUM_ARITH_TBLS; i++) 244 length += dc_in_use[i] + ac_in_use[i]; 245 246 emit_marker(cinfo, M_DAC); 247 248 emit_2bytes(cinfo, length*2 + 2); 249 250 for (i = 0; i < NUM_ARITH_TBLS; i++) { 251 if (dc_in_use[i]) { 252 emit_byte(cinfo, i); 253 emit_byte(cinfo, cinfo->arith_dc_L[i] + (cinfo->arith_dc_U[i]<<4)); 254 } 255 if (ac_in_use[i]) { 256 emit_byte(cinfo, i + 0x10); 257 emit_byte(cinfo, cinfo->arith_ac_K[i]); 258 } 259 } 260 #endif /* C_ARITH_CODING_SUPPORTED */ 261 } 262 263 264 LOCAL(void) 265 emit_dri (j_compress_ptr cinfo) 266 /* Emit a DRI marker */ 267 { 268 emit_marker(cinfo, M_DRI); 269 270 emit_2bytes(cinfo, 4); /* fixed length */ 271 272 emit_2bytes(cinfo, (int) cinfo->restart_interval); 273 } 274 275 276 LOCAL(void) 277 emit_sof (j_compress_ptr cinfo, JPEG_MARKER code) 278 /* Emit a SOF marker */ 279 { 280 int ci; 281 jpeg_component_info *compptr; 282 283 emit_marker(cinfo, code); 284 285 emit_2bytes(cinfo, 3 * cinfo->num_components + 2 + 5 + 1); /* length */ 286 287 /* Make sure image isn't bigger than SOF field can handle */ 288 if ((long) cinfo->image_height > 65535L || 289 (long) cinfo->image_width > 65535L) 290 ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) 65535); 291 292 emit_byte(cinfo, cinfo->data_precision); 293 emit_2bytes(cinfo, (int) cinfo->image_height); 294 emit_2bytes(cinfo, (int) cinfo->image_width); 295 296 emit_byte(cinfo, cinfo->num_components); 297 298 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 299 ci++, compptr++) { 300 emit_byte(cinfo, compptr->component_id); 301 emit_byte(cinfo, (compptr->h_samp_factor << 4) + compptr->v_samp_factor); 302 emit_byte(cinfo, compptr->quant_tbl_no); 303 } 304 } 305 306 307 LOCAL(void) 308 emit_sos (j_compress_ptr cinfo) 309 /* Emit a SOS marker */ 310 { 311 int i, td, ta; 312 jpeg_component_info *compptr; 313 314 emit_marker(cinfo, M_SOS); 315 316 emit_2bytes(cinfo, 2 * cinfo->comps_in_scan + 2 + 1 + 3); /* length */ 317 318 emit_byte(cinfo, cinfo->comps_in_scan); 319 320 for (i = 0; i < cinfo->comps_in_scan; i++) { 321 compptr = cinfo->cur_comp_info[i]; 322 emit_byte(cinfo, compptr->component_id); 323 td = compptr->dc_tbl_no; 324 ta = compptr->ac_tbl_no; 325 if (cinfo->progressive_mode) { 326 /* Progressive mode: only DC or only AC tables are used in one scan; 327 * furthermore, Huffman coding of DC refinement uses no table at all. 328 * We emit 0 for unused field(s); this is recommended by the P&M text 329 * but does not seem to be specified in the standard. 330 */ 331 if (cinfo->Ss == 0) { 332 ta = 0; /* DC scan */ 333 if (cinfo->Ah != 0 && !cinfo->arith_code) 334 td = 0; /* no DC table either */ 335 } else { 336 td = 0; /* AC scan */ 337 } 338 } 339 emit_byte(cinfo, (td << 4) + ta); 340 } 341 342 emit_byte(cinfo, cinfo->Ss); 343 emit_byte(cinfo, cinfo->Se); 344 emit_byte(cinfo, (cinfo->Ah << 4) + cinfo->Al); 345 } 346 347 348 LOCAL(void) 349 emit_jfif_app0 (j_compress_ptr cinfo) 350 /* Emit a JFIF-compliant APP0 marker */ 351 { 352 /* 353 * Length of APP0 block (2 bytes) 354 * Block ID (4 bytes - ASCII "JFIF") 355 * Zero byte (1 byte to terminate the ID string) 356 * Version Major, Minor (2 bytes - major first) 357 * Units (1 byte - 0x00 = none, 0x01 = inch, 0x02 = cm) 358 * Xdpu (2 bytes - dots per unit horizontal) 359 * Ydpu (2 bytes - dots per unit vertical) 360 * Thumbnail X size (1 byte) 361 * Thumbnail Y size (1 byte) 362 */ 363 364 emit_marker(cinfo, M_APP0); 365 366 emit_2bytes(cinfo, 2 + 4 + 1 + 2 + 1 + 2 + 2 + 1 + 1); /* length */ 367 368 emit_byte(cinfo, 0x4A); /* Identifier: ASCII "JFIF" */ 369 emit_byte(cinfo, 0x46); 370 emit_byte(cinfo, 0x49); 371 emit_byte(cinfo, 0x46); 372 emit_byte(cinfo, 0); 373 emit_byte(cinfo, cinfo->JFIF_major_version); /* Version fields */ 374 emit_byte(cinfo, cinfo->JFIF_minor_version); 375 emit_byte(cinfo, cinfo->density_unit); /* Pixel size information */ 376 emit_2bytes(cinfo, (int) cinfo->X_density); 377 emit_2bytes(cinfo, (int) cinfo->Y_density); 378 emit_byte(cinfo, 0); /* No thumbnail image */ 379 emit_byte(cinfo, 0); 380 } 381 382 383 LOCAL(void) 384 emit_adobe_app14 (j_compress_ptr cinfo) 385 /* Emit an Adobe APP14 marker */ 386 { 387 /* 388 * Length of APP14 block (2 bytes) 389 * Block ID (5 bytes - ASCII "Adobe") 390 * Version Number (2 bytes - currently 100) 391 * Flags0 (2 bytes - currently 0) 392 * Flags1 (2 bytes - currently 0) 393 * Color transform (1 byte) 394 * 395 * Although Adobe TN 5116 mentions Version = 101, all the Adobe files 396 * now in circulation seem to use Version = 100, so that's what we write. 397 * 398 * We write the color transform byte as 1 if the JPEG color space is 399 * YCbCr, 2 if it's YCCK, 0 otherwise. Adobe's definition has to do with 400 * whether the encoder performed a transformation, which is pretty useless. 401 */ 402 403 emit_marker(cinfo, M_APP14); 404 405 emit_2bytes(cinfo, 2 + 5 + 2 + 2 + 2 + 1); /* length */ 406 407 emit_byte(cinfo, 0x41); /* Identifier: ASCII "Adobe" */ 408 emit_byte(cinfo, 0x64); 409 emit_byte(cinfo, 0x6F); 410 emit_byte(cinfo, 0x62); 411 emit_byte(cinfo, 0x65); 412 emit_2bytes(cinfo, 100); /* Version */ 413 emit_2bytes(cinfo, 0); /* Flags0 */ 414 emit_2bytes(cinfo, 0); /* Flags1 */ 415 switch (cinfo->jpeg_color_space) { 416 case JCS_YCbCr: 417 emit_byte(cinfo, 1); /* Color transform = 1 */ 418 break; 419 case JCS_YCCK: 420 emit_byte(cinfo, 2); /* Color transform = 2 */ 421 break; 422 default: 423 emit_byte(cinfo, 0); /* Color transform = 0 */ 424 break; 425 } 426 } 427 428 429 /* 430 * These routines allow writing an arbitrary marker with parameters. 431 * The only intended use is to emit COM or APPn markers after calling 432 * write_file_header and before calling write_frame_header. 433 * Other uses are not guaranteed to produce desirable results. 434 * Counting the parameter bytes properly is the caller's responsibility. 435 */ 436 437 METHODDEF(void) 438 write_marker_header (j_compress_ptr cinfo, int marker, unsigned int datalen) 439 /* Emit an arbitrary marker header */ 440 { 441 if (datalen > (unsigned int) 65533) /* safety check */ 442 ERREXIT(cinfo, JERR_BAD_LENGTH); 443 444 emit_marker(cinfo, (JPEG_MARKER) marker); 445 446 emit_2bytes(cinfo, (int) (datalen + 2)); /* total length */ 447 } 448 449 METHODDEF(void) 450 write_marker_byte (j_compress_ptr cinfo, int val) 451 /* Emit one byte of marker parameters following write_marker_header */ 452 { 453 emit_byte(cinfo, val); 454 } 455 456 457 /* 458 * Write datastream header. 459 * This consists of an SOI and optional APPn markers. 460 * We recommend use of the JFIF marker, but not the Adobe marker, 461 * when using YCbCr or grayscale data. The JFIF marker should NOT 462 * be used for any other JPEG colorspace. The Adobe marker is helpful 463 * to distinguish RGB, CMYK, and YCCK colorspaces. 464 * Note that an application can write additional header markers after 465 * jpeg_start_compress returns. 466 */ 467 468 METHODDEF(void) 469 write_file_header (j_compress_ptr cinfo) 470 { 471 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 472 473 emit_marker(cinfo, M_SOI); /* first the SOI */ 474 475 /* SOI is defined to reset restart interval to 0 */ 476 marker->last_restart_interval = 0; 477 478 if (cinfo->write_JFIF_header) /* next an optional JFIF APP0 */ 479 emit_jfif_app0(cinfo); 480 if (cinfo->write_Adobe_marker) /* next an optional Adobe APP14 */ 481 emit_adobe_app14(cinfo); 482 } 483 484 485 /* 486 * Write frame header. 487 * This consists of DQT and SOFn markers. 488 * Note that we do not emit the SOF until we have emitted the DQT(s). 489 * This avoids compatibility problems with incorrect implementations that 490 * try to error-check the quant table numbers as soon as they see the SOF. 491 */ 492 493 METHODDEF(void) 494 write_frame_header (j_compress_ptr cinfo) 495 { 496 int ci, prec; 497 boolean is_baseline; 498 jpeg_component_info *compptr; 499 500 /* Emit DQT for each quantization table. 501 * Note that emit_dqt() suppresses any duplicate tables. 502 */ 503 prec = 0; 504 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 505 ci++, compptr++) { 506 prec += emit_dqt(cinfo, compptr->quant_tbl_no); 507 } 508 /* now prec is nonzero iff there are any 16-bit quant tables. */ 509 510 /* Check for a non-baseline specification. 511 * Note we assume that Huffman table numbers won't be changed later. 512 */ 513 if (cinfo->arith_code || cinfo->progressive_mode || 514 cinfo->data_precision != 8) { 515 is_baseline = FALSE; 516 } else { 517 is_baseline = TRUE; 518 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 519 ci++, compptr++) { 520 if (compptr->dc_tbl_no > 1 || compptr->ac_tbl_no > 1) 521 is_baseline = FALSE; 522 } 523 if (prec && is_baseline) { 524 is_baseline = FALSE; 525 /* If it's baseline except for quantizer size, warn the user */ 526 TRACEMS(cinfo, 0, JTRC_16BIT_TABLES); 527 } 528 } 529 530 /* Emit the proper SOF marker */ 531 if (cinfo->arith_code) { 532 emit_sof(cinfo, M_SOF9); /* SOF code for arithmetic coding */ 533 } else { 534 if (cinfo->progressive_mode) 535 emit_sof(cinfo, M_SOF2); /* SOF code for progressive Huffman */ 536 else if (is_baseline) 537 emit_sof(cinfo, M_SOF0); /* SOF code for baseline implementation */ 538 else 539 emit_sof(cinfo, M_SOF1); /* SOF code for non-baseline Huffman file */ 540 } 541 } 542 543 544 /* 545 * Write scan header. 546 * This consists of DHT or DAC markers, optional DRI, and SOS. 547 * Compressed data will be written following the SOS. 548 */ 549 550 METHODDEF(void) 551 write_scan_header (j_compress_ptr cinfo) 552 { 553 my_marker_ptr marker = (my_marker_ptr) cinfo->marker; 554 int i; 555 jpeg_component_info *compptr; 556 557 if (cinfo->arith_code) { 558 /* Emit arith conditioning info. We may have some duplication 559 * if the file has multiple scans, but it's so small it's hardly 560 * worth worrying about. 561 */ 562 emit_dac(cinfo); 563 } else { 564 /* Emit Huffman tables. 565 * Note that emit_dht() suppresses any duplicate tables. 566 */ 567 for (i = 0; i < cinfo->comps_in_scan; i++) { 568 compptr = cinfo->cur_comp_info[i]; 569 if (cinfo->progressive_mode) { 570 /* Progressive mode: only DC or only AC tables are used in one scan */ 571 if (cinfo->Ss == 0) { 572 if (cinfo->Ah == 0) /* DC needs no table for refinement scan */ 573 emit_dht(cinfo, compptr->dc_tbl_no, FALSE); 574 } else { 575 emit_dht(cinfo, compptr->ac_tbl_no, TRUE); 576 } 577 } else { 578 /* Sequential mode: need both DC and AC tables */ 579 emit_dht(cinfo, compptr->dc_tbl_no, FALSE); 580 emit_dht(cinfo, compptr->ac_tbl_no, TRUE); 581 } 582 } 583 } 584 585 /* Emit DRI if required --- note that DRI value could change for each scan. 586 * We avoid wasting space with unnecessary DRIs, however. 587 */ 588 if (cinfo->restart_interval != marker->last_restart_interval) { 589 emit_dri(cinfo); 590 marker->last_restart_interval = cinfo->restart_interval; 591 } 592 593 emit_sos(cinfo); 594 } 595 596 597 /* 598 * Write datastream trailer. 599 */ 600 601 METHODDEF(void) 602 write_file_trailer (j_compress_ptr cinfo) 603 { 604 emit_marker(cinfo, M_EOI); 605 } 606 607 608 /* 609 * Write an abbreviated table-specification datastream. 610 * This consists of SOI, DQT and DHT tables, and EOI. 611 * Any table that is defined and not marked sent_table = TRUE will be 612 * emitted. Note that all tables will be marked sent_table = TRUE at exit. 613 */ 614 615 METHODDEF(void) 616 write_tables_only (j_compress_ptr cinfo) 617 { 618 int i; 619 620 emit_marker(cinfo, M_SOI); 621 622 for (i = 0; i < NUM_QUANT_TBLS; i++) { 623 if (cinfo->quant_tbl_ptrs[i] != NULL) 624 (void) emit_dqt(cinfo, i); 625 } 626 627 if (! cinfo->arith_code) { 628 for (i = 0; i < NUM_HUFF_TBLS; i++) { 629 if (cinfo->dc_huff_tbl_ptrs[i] != NULL) 630 emit_dht(cinfo, i, FALSE); 631 if (cinfo->ac_huff_tbl_ptrs[i] != NULL) 632 emit_dht(cinfo, i, TRUE); 633 } 634 } 635 636 emit_marker(cinfo, M_EOI); 637 } 638 639 640 /* 641 * Initialize the marker writer module. 642 */ 643 644 GLOBAL(void) 645 jinit_marker_writer (j_compress_ptr cinfo) 646 { 647 my_marker_ptr marker; 648 649 /* Create the subobject */ 650 marker = (my_marker_ptr) 651 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 652 SIZEOF(my_marker_writer)); 653 cinfo->marker = (struct jpeg_marker_writer *) marker; 654 /* Initialize method pointers */ 655 marker->pub.write_file_header = write_file_header; 656 marker->pub.write_frame_header = write_frame_header; 657 marker->pub.write_scan_header = write_scan_header; 658 marker->pub.write_file_trailer = write_file_trailer; 659 marker->pub.write_tables_only = write_tables_only; 660 marker->pub.write_marker_header = write_marker_header; 661 marker->pub.write_marker_byte = write_marker_byte; 662 /* Initialize private state */ 663 marker->last_restart_interval = 0; 664 } 665
