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annotate libs/libjpeg/jcmarker.c @ 13:ea928c313344

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author John Tsiombikas <nuclear@member.fsf.org>
date Mon, 28 Sep 2015 19:04:50 +0300
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nuclear@2 1 /*
nuclear@2 2 * jcmarker.c
nuclear@2 3 *
nuclear@2 4 * Copyright (C) 1991-1998, Thomas G. Lane.
nuclear@2 5 * This file is part of the Independent JPEG Group's software.
nuclear@2 6 * For conditions of distribution and use, see the accompanying README file.
nuclear@2 7 *
nuclear@2 8 * This file contains routines to write JPEG datastream markers.
nuclear@2 9 */
nuclear@2 10
nuclear@2 11 #define JPEG_INTERNALS
nuclear@2 12 #include "jinclude.h"
nuclear@2 13 #include "jpeglib.h"
nuclear@2 14
nuclear@2 15
nuclear@2 16 typedef enum { /* JPEG marker codes */
nuclear@2 17 M_SOF0 = 0xc0,
nuclear@2 18 M_SOF1 = 0xc1,
nuclear@2 19 M_SOF2 = 0xc2,
nuclear@2 20 M_SOF3 = 0xc3,
nuclear@2 21
nuclear@2 22 M_SOF5 = 0xc5,
nuclear@2 23 M_SOF6 = 0xc6,
nuclear@2 24 M_SOF7 = 0xc7,
nuclear@2 25
nuclear@2 26 M_JPG = 0xc8,
nuclear@2 27 M_SOF9 = 0xc9,
nuclear@2 28 M_SOF10 = 0xca,
nuclear@2 29 M_SOF11 = 0xcb,
nuclear@2 30
nuclear@2 31 M_SOF13 = 0xcd,
nuclear@2 32 M_SOF14 = 0xce,
nuclear@2 33 M_SOF15 = 0xcf,
nuclear@2 34
nuclear@2 35 M_DHT = 0xc4,
nuclear@2 36
nuclear@2 37 M_DAC = 0xcc,
nuclear@2 38
nuclear@2 39 M_RST0 = 0xd0,
nuclear@2 40 M_RST1 = 0xd1,
nuclear@2 41 M_RST2 = 0xd2,
nuclear@2 42 M_RST3 = 0xd3,
nuclear@2 43 M_RST4 = 0xd4,
nuclear@2 44 M_RST5 = 0xd5,
nuclear@2 45 M_RST6 = 0xd6,
nuclear@2 46 M_RST7 = 0xd7,
nuclear@2 47
nuclear@2 48 M_SOI = 0xd8,
nuclear@2 49 M_EOI = 0xd9,
nuclear@2 50 M_SOS = 0xda,
nuclear@2 51 M_DQT = 0xdb,
nuclear@2 52 M_DNL = 0xdc,
nuclear@2 53 M_DRI = 0xdd,
nuclear@2 54 M_DHP = 0xde,
nuclear@2 55 M_EXP = 0xdf,
nuclear@2 56
nuclear@2 57 M_APP0 = 0xe0,
nuclear@2 58 M_APP1 = 0xe1,
nuclear@2 59 M_APP2 = 0xe2,
nuclear@2 60 M_APP3 = 0xe3,
nuclear@2 61 M_APP4 = 0xe4,
nuclear@2 62 M_APP5 = 0xe5,
nuclear@2 63 M_APP6 = 0xe6,
nuclear@2 64 M_APP7 = 0xe7,
nuclear@2 65 M_APP8 = 0xe8,
nuclear@2 66 M_APP9 = 0xe9,
nuclear@2 67 M_APP10 = 0xea,
nuclear@2 68 M_APP11 = 0xeb,
nuclear@2 69 M_APP12 = 0xec,
nuclear@2 70 M_APP13 = 0xed,
nuclear@2 71 M_APP14 = 0xee,
nuclear@2 72 M_APP15 = 0xef,
nuclear@2 73
nuclear@2 74 M_JPG0 = 0xf0,
nuclear@2 75 M_JPG13 = 0xfd,
nuclear@2 76 M_COM = 0xfe,
nuclear@2 77
nuclear@2 78 M_TEM = 0x01,
nuclear@2 79
nuclear@2 80 M_ERROR = 0x100
nuclear@2 81 } JPEG_MARKER;
nuclear@2 82
nuclear@2 83
nuclear@2 84 /* Private state */
nuclear@2 85
nuclear@2 86 typedef struct {
nuclear@2 87 struct jpeg_marker_writer pub; /* public fields */
nuclear@2 88
nuclear@2 89 unsigned int last_restart_interval; /* last DRI value emitted; 0 after SOI */
nuclear@2 90 } my_marker_writer;
nuclear@2 91
nuclear@2 92 typedef my_marker_writer * my_marker_ptr;
nuclear@2 93
nuclear@2 94
nuclear@2 95 /*
nuclear@2 96 * Basic output routines.
nuclear@2 97 *
nuclear@2 98 * Note that we do not support suspension while writing a marker.
nuclear@2 99 * Therefore, an application using suspension must ensure that there is
nuclear@2 100 * enough buffer space for the initial markers (typ. 600-700 bytes) before
nuclear@2 101 * calling jpeg_start_compress, and enough space to write the trailing EOI
nuclear@2 102 * (a few bytes) before calling jpeg_finish_compress. Multipass compression
nuclear@2 103 * modes are not supported at all with suspension, so those two are the only
nuclear@2 104 * points where markers will be written.
nuclear@2 105 */
nuclear@2 106
nuclear@2 107 LOCAL(void)
nuclear@2 108 emit_byte (j_compress_ptr cinfo, int val)
nuclear@2 109 /* Emit a byte */
nuclear@2 110 {
nuclear@2 111 struct jpeg_destination_mgr * dest = cinfo->dest;
nuclear@2 112
nuclear@2 113 *(dest->next_output_byte)++ = (JOCTET) val;
nuclear@2 114 if (--dest->free_in_buffer == 0) {
nuclear@2 115 if (! (*dest->empty_output_buffer) (cinfo))
nuclear@2 116 ERREXIT(cinfo, JERR_CANT_SUSPEND);
nuclear@2 117 }
nuclear@2 118 }
nuclear@2 119
nuclear@2 120
nuclear@2 121 LOCAL(void)
nuclear@2 122 emit_marker (j_compress_ptr cinfo, JPEG_MARKER mark)
nuclear@2 123 /* Emit a marker code */
nuclear@2 124 {
nuclear@2 125 emit_byte(cinfo, 0xFF);
nuclear@2 126 emit_byte(cinfo, (int) mark);
nuclear@2 127 }
nuclear@2 128
nuclear@2 129
nuclear@2 130 LOCAL(void)
nuclear@2 131 emit_2bytes (j_compress_ptr cinfo, int value)
nuclear@2 132 /* Emit a 2-byte integer; these are always MSB first in JPEG files */
nuclear@2 133 {
nuclear@2 134 emit_byte(cinfo, (value >> 8) & 0xFF);
nuclear@2 135 emit_byte(cinfo, value & 0xFF);
nuclear@2 136 }
nuclear@2 137
nuclear@2 138
nuclear@2 139 /*
nuclear@2 140 * Routines to write specific marker types.
nuclear@2 141 */
nuclear@2 142
nuclear@2 143 LOCAL(int)
nuclear@2 144 emit_dqt (j_compress_ptr cinfo, int index)
nuclear@2 145 /* Emit a DQT marker */
nuclear@2 146 /* Returns the precision used (0 = 8bits, 1 = 16bits) for baseline checking */
nuclear@2 147 {
nuclear@2 148 JQUANT_TBL * qtbl = cinfo->quant_tbl_ptrs[index];
nuclear@2 149 int prec;
nuclear@2 150 int i;
nuclear@2 151
nuclear@2 152 if (qtbl == NULL)
nuclear@2 153 ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, index);
nuclear@2 154
nuclear@2 155 prec = 0;
nuclear@2 156 for (i = 0; i < DCTSIZE2; i++) {
nuclear@2 157 if (qtbl->quantval[i] > 255)
nuclear@2 158 prec = 1;
nuclear@2 159 }
nuclear@2 160
nuclear@2 161 if (! qtbl->sent_table) {
nuclear@2 162 emit_marker(cinfo, M_DQT);
nuclear@2 163
nuclear@2 164 emit_2bytes(cinfo, prec ? DCTSIZE2*2 + 1 + 2 : DCTSIZE2 + 1 + 2);
nuclear@2 165
nuclear@2 166 emit_byte(cinfo, index + (prec<<4));
nuclear@2 167
nuclear@2 168 for (i = 0; i < DCTSIZE2; i++) {
nuclear@2 169 /* The table entries must be emitted in zigzag order. */
nuclear@2 170 unsigned int qval = qtbl->quantval[jpeg_natural_order[i]];
nuclear@2 171 if (prec)
nuclear@2 172 emit_byte(cinfo, (int) (qval >> 8));
nuclear@2 173 emit_byte(cinfo, (int) (qval & 0xFF));
nuclear@2 174 }
nuclear@2 175
nuclear@2 176 qtbl->sent_table = TRUE;
nuclear@2 177 }
nuclear@2 178
nuclear@2 179 return prec;
nuclear@2 180 }
nuclear@2 181
nuclear@2 182
nuclear@2 183 LOCAL(void)
nuclear@2 184 emit_dht (j_compress_ptr cinfo, int index, boolean is_ac)
nuclear@2 185 /* Emit a DHT marker */
nuclear@2 186 {
nuclear@2 187 JHUFF_TBL * htbl;
nuclear@2 188 int length, i;
nuclear@2 189
nuclear@2 190 if (is_ac) {
nuclear@2 191 htbl = cinfo->ac_huff_tbl_ptrs[index];
nuclear@2 192 index += 0x10; /* output index has AC bit set */
nuclear@2 193 } else {
nuclear@2 194 htbl = cinfo->dc_huff_tbl_ptrs[index];
nuclear@2 195 }
nuclear@2 196
nuclear@2 197 if (htbl == NULL)
nuclear@2 198 ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, index);
nuclear@2 199
nuclear@2 200 if (! htbl->sent_table) {
nuclear@2 201 emit_marker(cinfo, M_DHT);
nuclear@2 202
nuclear@2 203 length = 0;
nuclear@2 204 for (i = 1; i <= 16; i++)
nuclear@2 205 length += htbl->bits[i];
nuclear@2 206
nuclear@2 207 emit_2bytes(cinfo, length + 2 + 1 + 16);
nuclear@2 208 emit_byte(cinfo, index);
nuclear@2 209
nuclear@2 210 for (i = 1; i <= 16; i++)
nuclear@2 211 emit_byte(cinfo, htbl->bits[i]);
nuclear@2 212
nuclear@2 213 for (i = 0; i < length; i++)
nuclear@2 214 emit_byte(cinfo, htbl->huffval[i]);
nuclear@2 215
nuclear@2 216 htbl->sent_table = TRUE;
nuclear@2 217 }
nuclear@2 218 }
nuclear@2 219
nuclear@2 220
nuclear@2 221 LOCAL(void)
nuclear@2 222 emit_dac (j_compress_ptr cinfo)
nuclear@2 223 /* Emit a DAC marker */
nuclear@2 224 /* Since the useful info is so small, we want to emit all the tables in */
nuclear@2 225 /* one DAC marker. Therefore this routine does its own scan of the table. */
nuclear@2 226 {
nuclear@2 227 #ifdef C_ARITH_CODING_SUPPORTED
nuclear@2 228 char dc_in_use[NUM_ARITH_TBLS];
nuclear@2 229 char ac_in_use[NUM_ARITH_TBLS];
nuclear@2 230 int length, i;
nuclear@2 231 jpeg_component_info *compptr;
nuclear@2 232
nuclear@2 233 for (i = 0; i < NUM_ARITH_TBLS; i++)
nuclear@2 234 dc_in_use[i] = ac_in_use[i] = 0;
nuclear@2 235
nuclear@2 236 for (i = 0; i < cinfo->comps_in_scan; i++) {
nuclear@2 237 compptr = cinfo->cur_comp_info[i];
nuclear@2 238 dc_in_use[compptr->dc_tbl_no] = 1;
nuclear@2 239 ac_in_use[compptr->ac_tbl_no] = 1;
nuclear@2 240 }
nuclear@2 241
nuclear@2 242 length = 0;
nuclear@2 243 for (i = 0; i < NUM_ARITH_TBLS; i++)
nuclear@2 244 length += dc_in_use[i] + ac_in_use[i];
nuclear@2 245
nuclear@2 246 emit_marker(cinfo, M_DAC);
nuclear@2 247
nuclear@2 248 emit_2bytes(cinfo, length*2 + 2);
nuclear@2 249
nuclear@2 250 for (i = 0; i < NUM_ARITH_TBLS; i++) {
nuclear@2 251 if (dc_in_use[i]) {
nuclear@2 252 emit_byte(cinfo, i);
nuclear@2 253 emit_byte(cinfo, cinfo->arith_dc_L[i] + (cinfo->arith_dc_U[i]<<4));
nuclear@2 254 }
nuclear@2 255 if (ac_in_use[i]) {
nuclear@2 256 emit_byte(cinfo, i + 0x10);
nuclear@2 257 emit_byte(cinfo, cinfo->arith_ac_K[i]);
nuclear@2 258 }
nuclear@2 259 }
nuclear@2 260 #endif /* C_ARITH_CODING_SUPPORTED */
nuclear@2 261 }
nuclear@2 262
nuclear@2 263
nuclear@2 264 LOCAL(void)
nuclear@2 265 emit_dri (j_compress_ptr cinfo)
nuclear@2 266 /* Emit a DRI marker */
nuclear@2 267 {
nuclear@2 268 emit_marker(cinfo, M_DRI);
nuclear@2 269
nuclear@2 270 emit_2bytes(cinfo, 4); /* fixed length */
nuclear@2 271
nuclear@2 272 emit_2bytes(cinfo, (int) cinfo->restart_interval);
nuclear@2 273 }
nuclear@2 274
nuclear@2 275
nuclear@2 276 LOCAL(void)
nuclear@2 277 emit_sof (j_compress_ptr cinfo, JPEG_MARKER code)
nuclear@2 278 /* Emit a SOF marker */
nuclear@2 279 {
nuclear@2 280 int ci;
nuclear@2 281 jpeg_component_info *compptr;
nuclear@2 282
nuclear@2 283 emit_marker(cinfo, code);
nuclear@2 284
nuclear@2 285 emit_2bytes(cinfo, 3 * cinfo->num_components + 2 + 5 + 1); /* length */
nuclear@2 286
nuclear@2 287 /* Make sure image isn't bigger than SOF field can handle */
nuclear@2 288 if ((long) cinfo->image_height > 65535L ||
nuclear@2 289 (long) cinfo->image_width > 65535L)
nuclear@2 290 ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) 65535);
nuclear@2 291
nuclear@2 292 emit_byte(cinfo, cinfo->data_precision);
nuclear@2 293 emit_2bytes(cinfo, (int) cinfo->image_height);
nuclear@2 294 emit_2bytes(cinfo, (int) cinfo->image_width);
nuclear@2 295
nuclear@2 296 emit_byte(cinfo, cinfo->num_components);
nuclear@2 297
nuclear@2 298 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
nuclear@2 299 ci++, compptr++) {
nuclear@2 300 emit_byte(cinfo, compptr->component_id);
nuclear@2 301 emit_byte(cinfo, (compptr->h_samp_factor << 4) + compptr->v_samp_factor);
nuclear@2 302 emit_byte(cinfo, compptr->quant_tbl_no);
nuclear@2 303 }
nuclear@2 304 }
nuclear@2 305
nuclear@2 306
nuclear@2 307 LOCAL(void)
nuclear@2 308 emit_sos (j_compress_ptr cinfo)
nuclear@2 309 /* Emit a SOS marker */
nuclear@2 310 {
nuclear@2 311 int i, td, ta;
nuclear@2 312 jpeg_component_info *compptr;
nuclear@2 313
nuclear@2 314 emit_marker(cinfo, M_SOS);
nuclear@2 315
nuclear@2 316 emit_2bytes(cinfo, 2 * cinfo->comps_in_scan + 2 + 1 + 3); /* length */
nuclear@2 317
nuclear@2 318 emit_byte(cinfo, cinfo->comps_in_scan);
nuclear@2 319
nuclear@2 320 for (i = 0; i < cinfo->comps_in_scan; i++) {
nuclear@2 321 compptr = cinfo->cur_comp_info[i];
nuclear@2 322 emit_byte(cinfo, compptr->component_id);
nuclear@2 323 td = compptr->dc_tbl_no;
nuclear@2 324 ta = compptr->ac_tbl_no;
nuclear@2 325 if (cinfo->progressive_mode) {
nuclear@2 326 /* Progressive mode: only DC or only AC tables are used in one scan;
nuclear@2 327 * furthermore, Huffman coding of DC refinement uses no table at all.
nuclear@2 328 * We emit 0 for unused field(s); this is recommended by the P&M text
nuclear@2 329 * but does not seem to be specified in the standard.
nuclear@2 330 */
nuclear@2 331 if (cinfo->Ss == 0) {
nuclear@2 332 ta = 0; /* DC scan */
nuclear@2 333 if (cinfo->Ah != 0 && !cinfo->arith_code)
nuclear@2 334 td = 0; /* no DC table either */
nuclear@2 335 } else {
nuclear@2 336 td = 0; /* AC scan */
nuclear@2 337 }
nuclear@2 338 }
nuclear@2 339 emit_byte(cinfo, (td << 4) + ta);
nuclear@2 340 }
nuclear@2 341
nuclear@2 342 emit_byte(cinfo, cinfo->Ss);
nuclear@2 343 emit_byte(cinfo, cinfo->Se);
nuclear@2 344 emit_byte(cinfo, (cinfo->Ah << 4) + cinfo->Al);
nuclear@2 345 }
nuclear@2 346
nuclear@2 347
nuclear@2 348 LOCAL(void)
nuclear@2 349 emit_jfif_app0 (j_compress_ptr cinfo)
nuclear@2 350 /* Emit a JFIF-compliant APP0 marker */
nuclear@2 351 {
nuclear@2 352 /*
nuclear@2 353 * Length of APP0 block (2 bytes)
nuclear@2 354 * Block ID (4 bytes - ASCII "JFIF")
nuclear@2 355 * Zero byte (1 byte to terminate the ID string)
nuclear@2 356 * Version Major, Minor (2 bytes - major first)
nuclear@2 357 * Units (1 byte - 0x00 = none, 0x01 = inch, 0x02 = cm)
nuclear@2 358 * Xdpu (2 bytes - dots per unit horizontal)
nuclear@2 359 * Ydpu (2 bytes - dots per unit vertical)
nuclear@2 360 * Thumbnail X size (1 byte)
nuclear@2 361 * Thumbnail Y size (1 byte)
nuclear@2 362 */
nuclear@2 363
nuclear@2 364 emit_marker(cinfo, M_APP0);
nuclear@2 365
nuclear@2 366 emit_2bytes(cinfo, 2 + 4 + 1 + 2 + 1 + 2 + 2 + 1 + 1); /* length */
nuclear@2 367
nuclear@2 368 emit_byte(cinfo, 0x4A); /* Identifier: ASCII "JFIF" */
nuclear@2 369 emit_byte(cinfo, 0x46);
nuclear@2 370 emit_byte(cinfo, 0x49);
nuclear@2 371 emit_byte(cinfo, 0x46);
nuclear@2 372 emit_byte(cinfo, 0);
nuclear@2 373 emit_byte(cinfo, cinfo->JFIF_major_version); /* Version fields */
nuclear@2 374 emit_byte(cinfo, cinfo->JFIF_minor_version);
nuclear@2 375 emit_byte(cinfo, cinfo->density_unit); /* Pixel size information */
nuclear@2 376 emit_2bytes(cinfo, (int) cinfo->X_density);
nuclear@2 377 emit_2bytes(cinfo, (int) cinfo->Y_density);
nuclear@2 378 emit_byte(cinfo, 0); /* No thumbnail image */
nuclear@2 379 emit_byte(cinfo, 0);
nuclear@2 380 }
nuclear@2 381
nuclear@2 382
nuclear@2 383 LOCAL(void)
nuclear@2 384 emit_adobe_app14 (j_compress_ptr cinfo)
nuclear@2 385 /* Emit an Adobe APP14 marker */
nuclear@2 386 {
nuclear@2 387 /*
nuclear@2 388 * Length of APP14 block (2 bytes)
nuclear@2 389 * Block ID (5 bytes - ASCII "Adobe")
nuclear@2 390 * Version Number (2 bytes - currently 100)
nuclear@2 391 * Flags0 (2 bytes - currently 0)
nuclear@2 392 * Flags1 (2 bytes - currently 0)
nuclear@2 393 * Color transform (1 byte)
nuclear@2 394 *
nuclear@2 395 * Although Adobe TN 5116 mentions Version = 101, all the Adobe files
nuclear@2 396 * now in circulation seem to use Version = 100, so that's what we write.
nuclear@2 397 *
nuclear@2 398 * We write the color transform byte as 1 if the JPEG color space is
nuclear@2 399 * YCbCr, 2 if it's YCCK, 0 otherwise. Adobe's definition has to do with
nuclear@2 400 * whether the encoder performed a transformation, which is pretty useless.
nuclear@2 401 */
nuclear@2 402
nuclear@2 403 emit_marker(cinfo, M_APP14);
nuclear@2 404
nuclear@2 405 emit_2bytes(cinfo, 2 + 5 + 2 + 2 + 2 + 1); /* length */
nuclear@2 406
nuclear@2 407 emit_byte(cinfo, 0x41); /* Identifier: ASCII "Adobe" */
nuclear@2 408 emit_byte(cinfo, 0x64);
nuclear@2 409 emit_byte(cinfo, 0x6F);
nuclear@2 410 emit_byte(cinfo, 0x62);
nuclear@2 411 emit_byte(cinfo, 0x65);
nuclear@2 412 emit_2bytes(cinfo, 100); /* Version */
nuclear@2 413 emit_2bytes(cinfo, 0); /* Flags0 */
nuclear@2 414 emit_2bytes(cinfo, 0); /* Flags1 */
nuclear@2 415 switch (cinfo->jpeg_color_space) {
nuclear@2 416 case JCS_YCbCr:
nuclear@2 417 emit_byte(cinfo, 1); /* Color transform = 1 */
nuclear@2 418 break;
nuclear@2 419 case JCS_YCCK:
nuclear@2 420 emit_byte(cinfo, 2); /* Color transform = 2 */
nuclear@2 421 break;
nuclear@2 422 default:
nuclear@2 423 emit_byte(cinfo, 0); /* Color transform = 0 */
nuclear@2 424 break;
nuclear@2 425 }
nuclear@2 426 }
nuclear@2 427
nuclear@2 428
nuclear@2 429 /*
nuclear@2 430 * These routines allow writing an arbitrary marker with parameters.
nuclear@2 431 * The only intended use is to emit COM or APPn markers after calling
nuclear@2 432 * write_file_header and before calling write_frame_header.
nuclear@2 433 * Other uses are not guaranteed to produce desirable results.
nuclear@2 434 * Counting the parameter bytes properly is the caller's responsibility.
nuclear@2 435 */
nuclear@2 436
nuclear@2 437 METHODDEF(void)
nuclear@2 438 write_marker_header (j_compress_ptr cinfo, int marker, unsigned int datalen)
nuclear@2 439 /* Emit an arbitrary marker header */
nuclear@2 440 {
nuclear@2 441 if (datalen > (unsigned int) 65533) /* safety check */
nuclear@2 442 ERREXIT(cinfo, JERR_BAD_LENGTH);
nuclear@2 443
nuclear@2 444 emit_marker(cinfo, (JPEG_MARKER) marker);
nuclear@2 445
nuclear@2 446 emit_2bytes(cinfo, (int) (datalen + 2)); /* total length */
nuclear@2 447 }
nuclear@2 448
nuclear@2 449 METHODDEF(void)
nuclear@2 450 write_marker_byte (j_compress_ptr cinfo, int val)
nuclear@2 451 /* Emit one byte of marker parameters following write_marker_header */
nuclear@2 452 {
nuclear@2 453 emit_byte(cinfo, val);
nuclear@2 454 }
nuclear@2 455
nuclear@2 456
nuclear@2 457 /*
nuclear@2 458 * Write datastream header.
nuclear@2 459 * This consists of an SOI and optional APPn markers.
nuclear@2 460 * We recommend use of the JFIF marker, but not the Adobe marker,
nuclear@2 461 * when using YCbCr or grayscale data. The JFIF marker should NOT
nuclear@2 462 * be used for any other JPEG colorspace. The Adobe marker is helpful
nuclear@2 463 * to distinguish RGB, CMYK, and YCCK colorspaces.
nuclear@2 464 * Note that an application can write additional header markers after
nuclear@2 465 * jpeg_start_compress returns.
nuclear@2 466 */
nuclear@2 467
nuclear@2 468 METHODDEF(void)
nuclear@2 469 write_file_header (j_compress_ptr cinfo)
nuclear@2 470 {
nuclear@2 471 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
nuclear@2 472
nuclear@2 473 emit_marker(cinfo, M_SOI); /* first the SOI */
nuclear@2 474
nuclear@2 475 /* SOI is defined to reset restart interval to 0 */
nuclear@2 476 marker->last_restart_interval = 0;
nuclear@2 477
nuclear@2 478 if (cinfo->write_JFIF_header) /* next an optional JFIF APP0 */
nuclear@2 479 emit_jfif_app0(cinfo);
nuclear@2 480 if (cinfo->write_Adobe_marker) /* next an optional Adobe APP14 */
nuclear@2 481 emit_adobe_app14(cinfo);
nuclear@2 482 }
nuclear@2 483
nuclear@2 484
nuclear@2 485 /*
nuclear@2 486 * Write frame header.
nuclear@2 487 * This consists of DQT and SOFn markers.
nuclear@2 488 * Note that we do not emit the SOF until we have emitted the DQT(s).
nuclear@2 489 * This avoids compatibility problems with incorrect implementations that
nuclear@2 490 * try to error-check the quant table numbers as soon as they see the SOF.
nuclear@2 491 */
nuclear@2 492
nuclear@2 493 METHODDEF(void)
nuclear@2 494 write_frame_header (j_compress_ptr cinfo)
nuclear@2 495 {
nuclear@2 496 int ci, prec;
nuclear@2 497 boolean is_baseline;
nuclear@2 498 jpeg_component_info *compptr;
nuclear@2 499
nuclear@2 500 /* Emit DQT for each quantization table.
nuclear@2 501 * Note that emit_dqt() suppresses any duplicate tables.
nuclear@2 502 */
nuclear@2 503 prec = 0;
nuclear@2 504 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
nuclear@2 505 ci++, compptr++) {
nuclear@2 506 prec += emit_dqt(cinfo, compptr->quant_tbl_no);
nuclear@2 507 }
nuclear@2 508 /* now prec is nonzero iff there are any 16-bit quant tables. */
nuclear@2 509
nuclear@2 510 /* Check for a non-baseline specification.
nuclear@2 511 * Note we assume that Huffman table numbers won't be changed later.
nuclear@2 512 */
nuclear@2 513 if (cinfo->arith_code || cinfo->progressive_mode ||
nuclear@2 514 cinfo->data_precision != 8) {
nuclear@2 515 is_baseline = FALSE;
nuclear@2 516 } else {
nuclear@2 517 is_baseline = TRUE;
nuclear@2 518 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
nuclear@2 519 ci++, compptr++) {
nuclear@2 520 if (compptr->dc_tbl_no > 1 || compptr->ac_tbl_no > 1)
nuclear@2 521 is_baseline = FALSE;
nuclear@2 522 }
nuclear@2 523 if (prec && is_baseline) {
nuclear@2 524 is_baseline = FALSE;
nuclear@2 525 /* If it's baseline except for quantizer size, warn the user */
nuclear@2 526 TRACEMS(cinfo, 0, JTRC_16BIT_TABLES);
nuclear@2 527 }
nuclear@2 528 }
nuclear@2 529
nuclear@2 530 /* Emit the proper SOF marker */
nuclear@2 531 if (cinfo->arith_code) {
nuclear@2 532 emit_sof(cinfo, M_SOF9); /* SOF code for arithmetic coding */
nuclear@2 533 } else {
nuclear@2 534 if (cinfo->progressive_mode)
nuclear@2 535 emit_sof(cinfo, M_SOF2); /* SOF code for progressive Huffman */
nuclear@2 536 else if (is_baseline)
nuclear@2 537 emit_sof(cinfo, M_SOF0); /* SOF code for baseline implementation */
nuclear@2 538 else
nuclear@2 539 emit_sof(cinfo, M_SOF1); /* SOF code for non-baseline Huffman file */
nuclear@2 540 }
nuclear@2 541 }
nuclear@2 542
nuclear@2 543
nuclear@2 544 /*
nuclear@2 545 * Write scan header.
nuclear@2 546 * This consists of DHT or DAC markers, optional DRI, and SOS.
nuclear@2 547 * Compressed data will be written following the SOS.
nuclear@2 548 */
nuclear@2 549
nuclear@2 550 METHODDEF(void)
nuclear@2 551 write_scan_header (j_compress_ptr cinfo)
nuclear@2 552 {
nuclear@2 553 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
nuclear@2 554 int i;
nuclear@2 555 jpeg_component_info *compptr;
nuclear@2 556
nuclear@2 557 if (cinfo->arith_code) {
nuclear@2 558 /* Emit arith conditioning info. We may have some duplication
nuclear@2 559 * if the file has multiple scans, but it's so small it's hardly
nuclear@2 560 * worth worrying about.
nuclear@2 561 */
nuclear@2 562 emit_dac(cinfo);
nuclear@2 563 } else {
nuclear@2 564 /* Emit Huffman tables.
nuclear@2 565 * Note that emit_dht() suppresses any duplicate tables.
nuclear@2 566 */
nuclear@2 567 for (i = 0; i < cinfo->comps_in_scan; i++) {
nuclear@2 568 compptr = cinfo->cur_comp_info[i];
nuclear@2 569 if (cinfo->progressive_mode) {
nuclear@2 570 /* Progressive mode: only DC or only AC tables are used in one scan */
nuclear@2 571 if (cinfo->Ss == 0) {
nuclear@2 572 if (cinfo->Ah == 0) /* DC needs no table for refinement scan */
nuclear@2 573 emit_dht(cinfo, compptr->dc_tbl_no, FALSE);
nuclear@2 574 } else {
nuclear@2 575 emit_dht(cinfo, compptr->ac_tbl_no, TRUE);
nuclear@2 576 }
nuclear@2 577 } else {
nuclear@2 578 /* Sequential mode: need both DC and AC tables */
nuclear@2 579 emit_dht(cinfo, compptr->dc_tbl_no, FALSE);
nuclear@2 580 emit_dht(cinfo, compptr->ac_tbl_no, TRUE);
nuclear@2 581 }
nuclear@2 582 }
nuclear@2 583 }
nuclear@2 584
nuclear@2 585 /* Emit DRI if required --- note that DRI value could change for each scan.
nuclear@2 586 * We avoid wasting space with unnecessary DRIs, however.
nuclear@2 587 */
nuclear@2 588 if (cinfo->restart_interval != marker->last_restart_interval) {
nuclear@2 589 emit_dri(cinfo);
nuclear@2 590 marker->last_restart_interval = cinfo->restart_interval;
nuclear@2 591 }
nuclear@2 592
nuclear@2 593 emit_sos(cinfo);
nuclear@2 594 }
nuclear@2 595
nuclear@2 596
nuclear@2 597 /*
nuclear@2 598 * Write datastream trailer.
nuclear@2 599 */
nuclear@2 600
nuclear@2 601 METHODDEF(void)
nuclear@2 602 write_file_trailer (j_compress_ptr cinfo)
nuclear@2 603 {
nuclear@2 604 emit_marker(cinfo, M_EOI);
nuclear@2 605 }
nuclear@2 606
nuclear@2 607
nuclear@2 608 /*
nuclear@2 609 * Write an abbreviated table-specification datastream.
nuclear@2 610 * This consists of SOI, DQT and DHT tables, and EOI.
nuclear@2 611 * Any table that is defined and not marked sent_table = TRUE will be
nuclear@2 612 * emitted. Note that all tables will be marked sent_table = TRUE at exit.
nuclear@2 613 */
nuclear@2 614
nuclear@2 615 METHODDEF(void)
nuclear@2 616 write_tables_only (j_compress_ptr cinfo)
nuclear@2 617 {
nuclear@2 618 int i;
nuclear@2 619
nuclear@2 620 emit_marker(cinfo, M_SOI);
nuclear@2 621
nuclear@2 622 for (i = 0; i < NUM_QUANT_TBLS; i++) {
nuclear@2 623 if (cinfo->quant_tbl_ptrs[i] != NULL)
nuclear@2 624 (void) emit_dqt(cinfo, i);
nuclear@2 625 }
nuclear@2 626
nuclear@2 627 if (! cinfo->arith_code) {
nuclear@2 628 for (i = 0; i < NUM_HUFF_TBLS; i++) {
nuclear@2 629 if (cinfo->dc_huff_tbl_ptrs[i] != NULL)
nuclear@2 630 emit_dht(cinfo, i, FALSE);
nuclear@2 631 if (cinfo->ac_huff_tbl_ptrs[i] != NULL)
nuclear@2 632 emit_dht(cinfo, i, TRUE);
nuclear@2 633 }
nuclear@2 634 }
nuclear@2 635
nuclear@2 636 emit_marker(cinfo, M_EOI);
nuclear@2 637 }
nuclear@2 638
nuclear@2 639
nuclear@2 640 /*
nuclear@2 641 * Initialize the marker writer module.
nuclear@2 642 */
nuclear@2 643
nuclear@2 644 GLOBAL(void)
nuclear@2 645 jinit_marker_writer (j_compress_ptr cinfo)
nuclear@2 646 {
nuclear@2 647 my_marker_ptr marker;
nuclear@2 648
nuclear@2 649 /* Create the subobject */
nuclear@2 650 marker = (my_marker_ptr)
nuclear@2 651 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
nuclear@2 652 SIZEOF(my_marker_writer));
nuclear@2 653 cinfo->marker = (struct jpeg_marker_writer *) marker;
nuclear@2 654 /* Initialize method pointers */
nuclear@2 655 marker->pub.write_file_header = write_file_header;
nuclear@2 656 marker->pub.write_frame_header = write_frame_header;
nuclear@2 657 marker->pub.write_scan_header = write_scan_header;
nuclear@2 658 marker->pub.write_file_trailer = write_file_trailer;
nuclear@2 659 marker->pub.write_tables_only = write_tables_only;
nuclear@2 660 marker->pub.write_marker_header = write_marker_header;
nuclear@2 661 marker->pub.write_marker_byte = write_marker_byte;
nuclear@2 662 /* Initialize private state */
nuclear@2 663 marker->last_restart_interval = 0;
nuclear@2 664 }