dll/3rdparty/libjpeg/jcmarker.c

   1 /*
   2  * jcmarker.c
   3  *
   4  * Copyright (C) 1991-1998, Thomas G. Lane.
   5  * Modified 2003-2013 by Guido Vollbeding.
   6  * This file is part of the Independent JPEG Group's software.
   7  * For conditions of distribution and use, see the accompanying README file.
   8  *
   9  * This file contains routines to write JPEG datastream markers.
  10  */
  11
  12 #define JPEG_INTERNALS
  13 #include "jinclude.h"
  14 #include "jpeglib.h"
  15
  16
  17 typedef enum {                  /* JPEG marker codes */
  18   M_SOF0  = 0xc0,
  19   M_SOF1  = 0xc1,
  20   M_SOF2  = 0xc2,
  21   M_SOF3  = 0xc3,
  22
  23   M_SOF5  = 0xc5,
  24   M_SOF6  = 0xc6,
  25   M_SOF7  = 0xc7,
  26
  27   M_JPG   = 0xc8,
  28   M_SOF9  = 0xc9,
  29   M_SOF10 = 0xca,
  30   M_SOF11 = 0xcb,
  31
  32   M_SOF13 = 0xcd,
  33   M_SOF14 = 0xce,
  34   M_SOF15 = 0xcf,
  35
  36   M_DHT   = 0xc4,
  37
  38   M_DAC   = 0xcc,
  39
  40   M_RST0  = 0xd0,
  41   M_RST1  = 0xd1,
  42   M_RST2  = 0xd2,
  43   M_RST3  = 0xd3,
  44   M_RST4  = 0xd4,
  45   M_RST5  = 0xd5,
  46   M_RST6  = 0xd6,
  47   M_RST7  = 0xd7,
  48
  49   M_SOI   = 0xd8,
  50   M_EOI   = 0xd9,
  51   M_SOS   = 0xda,
  52   M_DQT   = 0xdb,
  53   M_DNL   = 0xdc,
  54   M_DRI   = 0xdd,
  55   M_DHP   = 0xde,
  56   M_EXP   = 0xdf,
  57
  58   M_APP0  = 0xe0,
  59   M_APP1  = 0xe1,
  60   M_APP2  = 0xe2,
  61   M_APP3  = 0xe3,
  62   M_APP4  = 0xe4,
  63   M_APP5  = 0xe5,
  64   M_APP6  = 0xe6,
  65   M_APP7  = 0xe7,
  66   M_APP8  = 0xe8,
  67   M_APP9  = 0xe9,
  68   M_APP10 = 0xea,
  69   M_APP11 = 0xeb,
  70   M_APP12 = 0xec,
  71   M_APP13 = 0xed,
  72   M_APP14 = 0xee,
  73   M_APP15 = 0xef,
  74
  75   M_JPG0  = 0xf0,
  76   M_JPG8  = 0xf8,
  77   M_JPG13 = 0xfd,
  78   M_COM   = 0xfe,
  79
  80   M_TEM   = 0x01,
  81
  82   M_ERROR = 0x100
  83 } JPEG_MARKER;
  84
  85
  86 /* Private state */
  87
  88 typedef struct {
  89   struct jpeg_marker_writer pub; /* public fields */
  90
  91   unsigned int last_restart_interval; /* last DRI value emitted; 0 after SOI */
  92 } my_marker_writer;
  93
  94 typedef my_marker_writer * my_marker_ptr;
  95
  96
  97 /*
  98  * Basic output routines.
  99  *
 100  * Note that we do not support suspension while writing a marker.
 101  * Therefore, an application using suspension must ensure that there is
 102  * enough buffer space for the initial markers (typ. 600-700 bytes) before
 103  * calling jpeg_start_compress, and enough space to write the trailing EOI
 104  * (a few bytes) before calling jpeg_finish_compress.  Multipass compression
 105  * modes are not supported at all with suspension, so those two are the only
 106  * points where markers will be written.
 107  */
 108
 109 LOCAL(void)
 110 emit_byte (j_compress_ptr cinfo, int val)
 111 /* Emit a byte */
 112 {
 113   struct jpeg_destination_mgr * dest = cinfo->dest;
 114
 115   *(dest->next_output_byte)++ = (JOCTET) val;
 116   if (--dest->free_in_buffer == 0) {
 117     if (! (*dest->empty_output_buffer) (cinfo))
 118       ERREXIT(cinfo, JERR_CANT_SUSPEND);
 119   }
 120 }
 121
 122
 123 LOCAL(void)
 124 emit_marker (j_compress_ptr cinfo, JPEG_MARKER mark)
 125 /* Emit a marker code */
 126 {
 127   emit_byte(cinfo, 0xFF);
 128   emit_byte(cinfo, (int) mark);
 129 }
 130
 131
 132 LOCAL(void)
 133 emit_2bytes (j_compress_ptr cinfo, int value)
 134 /* Emit a 2-byte integer; these are always MSB first in JPEG files */
 135 {
 136   emit_byte(cinfo, (value >> 8) & 0xFF);
 137   emit_byte(cinfo, value & 0xFF);
 138 }
 139
 140
 141 /*
 142  * Routines to write specific marker types.
 143  */
 144
 145 LOCAL(int)
 146 emit_dqt (j_compress_ptr cinfo, int index)
 147 /* Emit a DQT marker */
 148 /* Returns the precision used (0 = 8bits, 1 = 16bits) for baseline checking */
 149 {
 150   JQUANT_TBL * qtbl = cinfo->quant_tbl_ptrs[index];
 151   int prec;
 152   int i;
 153
 154   if (qtbl == NULL)
 155     ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, index);
 156
 157   prec = 0;
 158   for (i = 0; i <= cinfo->lim_Se; i++) {
 159     if (qtbl->quantval[cinfo->natural_order[i]] > 255)
 160       prec = 1;
 161   }
 162
 163   if (! qtbl->sent_table) {
 164     emit_marker(cinfo, M_DQT);
 165
 166     emit_2bytes(cinfo,
 167       prec ? cinfo->lim_Se * 2 + 2 + 1 + 2 : cinfo->lim_Se + 1 + 1 + 2);
 168
 169     emit_byte(cinfo, index + (prec<<4));
 170
 171     for (i = 0; i <= cinfo->lim_Se; i++) {
 172       /* The table entries must be emitted in zigzag order. */
 173       unsigned int qval = qtbl->quantval[cinfo->natural_order[i]];
 174       if (prec)
 175         emit_byte(cinfo, (int) (qval >> 8));
 176       emit_byte(cinfo, (int) (qval & 0xFF));
 177     }
 178
 179     qtbl->sent_table = TRUE;
 180   }
 181
 182   return prec;
 183 }
 184
 185
 186 LOCAL(void)
 187 emit_dht (j_compress_ptr cinfo, int index, boolean is_ac)
 188 /* Emit a DHT marker */
 189 {
 190   JHUFF_TBL * htbl;
 191   int length, i;
 192
 193   if (is_ac) {
 194     htbl = cinfo->ac_huff_tbl_ptrs[index];
 195     index += 0x10;              /* output index has AC bit set */
 196   } else {
 197     htbl = cinfo->dc_huff_tbl_ptrs[index];
 198   }
 199
 200   if (htbl == NULL)
 201     ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, index);
 202
 203   if (! htbl->sent_table) {
 204     emit_marker(cinfo, M_DHT);
 205
 206     length = 0;
 207     for (i = 1; i <= 16; i++)
 208       length += htbl->bits[i];
 209
 210     emit_2bytes(cinfo, length + 2 + 1 + 16);
 211     emit_byte(cinfo, index);
 212
 213     for (i = 1; i <= 16; i++)
 214       emit_byte(cinfo, htbl->bits[i]);
 215
 216     for (i = 0; i < length; i++)
 217       emit_byte(cinfo, htbl->huffval[i]);
 218
 219     htbl->sent_table = TRUE;
 220   }
 221 }
 222
 223
 224 LOCAL(void)
 225 emit_dac (j_compress_ptr cinfo)
 226 /* Emit a DAC marker */
 227 /* Since the useful info is so small, we want to emit all the tables in */
 228 /* one DAC marker.  Therefore this routine does its own scan of the table. */
 229 {
 230 #ifdef C_ARITH_CODING_SUPPORTED
 231   char dc_in_use[NUM_ARITH_TBLS];
 232   char ac_in_use[NUM_ARITH_TBLS];
 233   int length, i;
 234   jpeg_component_info *compptr;
 235
 236   for (i = 0; i < NUM_ARITH_TBLS; i++)
 237     dc_in_use[i] = ac_in_use[i] = 0;
 238
 239   for (i = 0; i < cinfo->comps_in_scan; i++) {
 240     compptr = cinfo->cur_comp_info[i];
 241     /* DC needs no table for refinement scan */
 242     if (cinfo->Ss == 0 && cinfo->Ah == 0)
 243       dc_in_use[compptr->dc_tbl_no] = 1;
 244     /* AC needs no table when not present */
 245     if (cinfo->Se)
 246       ac_in_use[compptr->ac_tbl_no] = 1;
 247   }
 248
 249   length = 0;
 250   for (i = 0; i < NUM_ARITH_TBLS; i++)
 251     length += dc_in_use[i] + ac_in_use[i];
 252
 253   if (length) {
 254     emit_marker(cinfo, M_DAC);
 255
 256     emit_2bytes(cinfo, length*2 + 2);
 257
 258     for (i = 0; i < NUM_ARITH_TBLS; i++) {
 259       if (dc_in_use[i]) {
 260         emit_byte(cinfo, i);
 261         emit_byte(cinfo, cinfo->arith_dc_L[i] + (cinfo->arith_dc_U[i]<<4));
 262       }
 263       if (ac_in_use[i]) {
 264         emit_byte(cinfo, i + 0x10);
 265         emit_byte(cinfo, cinfo->arith_ac_K[i]);
 266       }
 267     }
 268   }
 269 #endif /* C_ARITH_CODING_SUPPORTED */
 270 }
 271
 272
 273 LOCAL(void)
 274 emit_dri (j_compress_ptr cinfo)
 275 /* Emit a DRI marker */
 276 {
 277   emit_marker(cinfo, M_DRI);
 278
 279   emit_2bytes(cinfo, 4);        /* fixed length */
 280
 281   emit_2bytes(cinfo, (int) cinfo->restart_interval);
 282 }
 283
 284
 285 LOCAL(void)
 286 emit_lse_ict (j_compress_ptr cinfo)
 287 /* Emit an LSE inverse color transform specification marker */
 288 {
 289   /* Support only 1 transform */
 290   if (cinfo->color_transform != JCT_SUBTRACT_GREEN ||
 291       cinfo->num_components < 3)
 292     ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
 293
 294   emit_marker(cinfo, M_JPG8);
 295
 296   emit_2bytes(cinfo, 24);       /* fixed length */
 297
 298   emit_byte(cinfo, 0x0D);       /* ID inverse transform specification */
 299   emit_2bytes(cinfo, MAXJSAMPLE);       /* MAXTRANS */
 300   emit_byte(cinfo, 3);          /* Nt=3 */
 301   emit_byte(cinfo, cinfo->comp_info[1].component_id);
 302   emit_byte(cinfo, cinfo->comp_info[0].component_id);
 303   emit_byte(cinfo, cinfo->comp_info[2].component_id);
 304   emit_byte(cinfo, 0x80);       /* F1: CENTER1=1, NORM1=0 */
 305   emit_2bytes(cinfo, 0);        /* A(1,1)=0 */
 306   emit_2bytes(cinfo, 0);        /* A(1,2)=0 */
 307   emit_byte(cinfo, 0);          /* F2: CENTER2=0, NORM2=0 */
 308   emit_2bytes(cinfo, 1);        /* A(2,1)=1 */
 309   emit_2bytes(cinfo, 0);        /* A(2,2)=0 */
 310   emit_byte(cinfo, 0);          /* F3: CENTER3=0, NORM3=0 */
 311   emit_2bytes(cinfo, 1);        /* A(3,1)=1 */
 312   emit_2bytes(cinfo, 0);        /* A(3,2)=0 */
 313 }
 314
 315
 316 LOCAL(void)
 317 emit_sof (j_compress_ptr cinfo, JPEG_MARKER code)
 318 /* Emit a SOF marker */
 319 {
 320   int ci;
 321   jpeg_component_info *compptr;
 322
 323   emit_marker(cinfo, code);
 324
 325   emit_2bytes(cinfo, 3 * cinfo->num_components + 2 + 5 + 1); /* length */
 326
 327   /* Make sure image isn't bigger than SOF field can handle */
 328   if ((long) cinfo->jpeg_height > 65535L ||
 329       (long) cinfo->jpeg_width > 65535L)
 330     ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) 65535);
 331
 332   emit_byte(cinfo, cinfo->data_precision);
 333   emit_2bytes(cinfo, (int) cinfo->jpeg_height);
 334   emit_2bytes(cinfo, (int) cinfo->jpeg_width);
 335
 336   emit_byte(cinfo, cinfo->num_components);
 337
 338   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
 339        ci++, compptr++) {
 340     emit_byte(cinfo, compptr->component_id);
 341     emit_byte(cinfo, (compptr->h_samp_factor << 4) + compptr->v_samp_factor);
 342     emit_byte(cinfo, compptr->quant_tbl_no);
 343   }
 344 }
 345
 346
 347 LOCAL(void)
 348 emit_sos (j_compress_ptr cinfo)
 349 /* Emit a SOS marker */
 350 {
 351   int i, td, ta;
 352   jpeg_component_info *compptr;
 353
 354   emit_marker(cinfo, M_SOS);
 355
 356   emit_2bytes(cinfo, 2 * cinfo->comps_in_scan + 2 + 1 + 3); /* length */
 357
 358   emit_byte(cinfo, cinfo->comps_in_scan);
 359
 360   for (i = 0; i < cinfo->comps_in_scan; i++) {
 361     compptr = cinfo->cur_comp_info[i];
 362     emit_byte(cinfo, compptr->component_id);
 363
 364     /* We emit 0 for unused field(s); this is recommended by the P&M text
 365      * but does not seem to be specified in the standard.
 366      */
 367
 368     /* DC needs no table for refinement scan */
 369     td = cinfo->Ss == 0 && cinfo->Ah == 0 ? compptr->dc_tbl_no : 0;
 370     /* AC needs no table when not present */
 371     ta = cinfo->Se ? compptr->ac_tbl_no : 0;
 372
 373     emit_byte(cinfo, (td << 4) + ta);
 374   }
 375
 376   emit_byte(cinfo, cinfo->Ss);
 377   emit_byte(cinfo, cinfo->Se);
 378   emit_byte(cinfo, (cinfo->Ah << 4) + cinfo->Al);
 379 }
 380
 381
 382 LOCAL(void)
 383 emit_pseudo_sos (j_compress_ptr cinfo)
 384 /* Emit a pseudo SOS marker */
 385 {
 386   emit_marker(cinfo, M_SOS);
 387
 388   emit_2bytes(cinfo, 2 + 1 + 3); /* length */
 389
 390   emit_byte(cinfo, 0); /* Ns */
 391
 392   emit_byte(cinfo, 0); /* Ss */
 393   emit_byte(cinfo, cinfo->block_size * cinfo->block_size - 1); /* Se */
 394   emit_byte(cinfo, 0); /* Ah/Al */
 395 }
 396
 397
 398 LOCAL(void)
 399 emit_jfif_app0 (j_compress_ptr cinfo)
 400 /* Emit a JFIF-compliant APP0 marker */
 401 {
 402   /*
 403    * Length of APP0 block       (2 bytes)
 404    * Block ID                   (4 bytes - ASCII "JFIF")
 405    * Zero byte                  (1 byte to terminate the ID string)
 406    * Version Major, Minor       (2 bytes - major first)
 407    * Units                      (1 byte - 0x00 = none, 0x01 = inch, 0x02 = cm)
 408    * Xdpu                       (2 bytes - dots per unit horizontal)
 409    * Ydpu                       (2 bytes - dots per unit vertical)
 410    * Thumbnail X size           (1 byte)
 411    * Thumbnail Y size           (1 byte)
 412    */
 413
 414   emit_marker(cinfo, M_APP0);
 415
 416   emit_2bytes(cinfo, 2 + 4 + 1 + 2 + 1 + 2 + 2 + 1 + 1); /* length */
 417
 418   emit_byte(cinfo, 0x4A);       /* Identifier: ASCII "JFIF" */
 419   emit_byte(cinfo, 0x46);
 420   emit_byte(cinfo, 0x49);
 421   emit_byte(cinfo, 0x46);
 422   emit_byte(cinfo, 0);
 423   emit_byte(cinfo, cinfo->JFIF_major_version); /* Version fields */
 424   emit_byte(cinfo, cinfo->JFIF_minor_version);
 425   emit_byte(cinfo, cinfo->density_unit); /* Pixel size information */
 426   emit_2bytes(cinfo, (int) cinfo->X_density);
 427   emit_2bytes(cinfo, (int) cinfo->Y_density);
 428   emit_byte(cinfo, 0);          /* No thumbnail image */
 429   emit_byte(cinfo, 0);
 430 }
 431
 432
 433 LOCAL(void)
 434 emit_adobe_app14 (j_compress_ptr cinfo)
 435 /* Emit an Adobe APP14 marker */
 436 {
 437   /*
 438    * Length of APP14 block      (2 bytes)
 439    * Block ID                   (5 bytes - ASCII "Adobe")
 440    * Version Number             (2 bytes - currently 100)
 441    * Flags0                     (2 bytes - currently 0)
 442    * Flags1                     (2 bytes - currently 0)
 443    * Color transform            (1 byte)
 444    *
 445    * Although Adobe TN 5116 mentions Version = 101, all the Adobe files
 446    * now in circulation seem to use Version = 100, so that's what we write.
 447    *
 448    * We write the color transform byte as 1 if the JPEG color space is
 449    * YCbCr, 2 if it's YCCK, 0 otherwise.  Adobe's definition has to do with
 450    * whether the encoder performed a transformation, which is pretty useless.
 451    */
 452
 453   emit_marker(cinfo, M_APP14);
 454
 455   emit_2bytes(cinfo, 2 + 5 + 2 + 2 + 2 + 1); /* length */
 456
 457   emit_byte(cinfo, 0x41);       /* Identifier: ASCII "Adobe" */
 458   emit_byte(cinfo, 0x64);
 459   emit_byte(cinfo, 0x6F);
 460   emit_byte(cinfo, 0x62);
 461   emit_byte(cinfo, 0x65);
 462   emit_2bytes(cinfo, 100);      /* Version */
 463   emit_2bytes(cinfo, 0);        /* Flags0 */
 464   emit_2bytes(cinfo, 0);        /* Flags1 */
 465   switch (cinfo->jpeg_color_space) {
 466   case JCS_YCbCr:
 467     emit_byte(cinfo, 1);        /* Color transform = 1 */
 468     break;
 469   case JCS_YCCK:
 470     emit_byte(cinfo, 2);        /* Color transform = 2 */
 471     break;
 472   default:
 473     emit_byte(cinfo, 0);        /* Color transform = 0 */
 474     break;
 475   }
 476 }
 477
 478
 479 /*
 480  * These routines allow writing an arbitrary marker with parameters.
 481  * The only intended use is to emit COM or APPn markers after calling
 482  * write_file_header and before calling write_frame_header.
 483  * Other uses are not guaranteed to produce desirable results.
 484  * Counting the parameter bytes properly is the caller's responsibility.
 485  */
 486
 487 METHODDEF(void)
 488 write_marker_header (j_compress_ptr cinfo, int marker, unsigned int datalen)
 489 /* Emit an arbitrary marker header */
 490 {
 491   if (datalen > (unsigned int) 65533)           /* safety check */
 492     ERREXIT(cinfo, JERR_BAD_LENGTH);
 493
 494   emit_marker(cinfo, (JPEG_MARKER) marker);
 495
 496   emit_2bytes(cinfo, (int) (datalen + 2));      /* total length */
 497 }
 498
 499 METHODDEF(void)
 500 write_marker_byte (j_compress_ptr cinfo, int val)
 501 /* Emit one byte of marker parameters following write_marker_header */
 502 {
 503   emit_byte(cinfo, val);
 504 }
 505
 506
 507 /*
 508  * Write datastream header.
 509  * This consists of an SOI and optional APPn markers.
 510  * We recommend use of the JFIF marker, but not the Adobe marker,
 511  * when using YCbCr or grayscale data.  The JFIF marker is also used
 512  * for other standard JPEG colorspaces.  The Adobe marker is helpful
 513  * to distinguish RGB, CMYK, and YCCK colorspaces.
 514  * Note that an application can write additional header markers after
 515  * jpeg_start_compress returns.
 516  */
 517
 518 METHODDEF(void)
 519 write_file_header (j_compress_ptr cinfo)
 520 {
 521   my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
 522
 523   emit_marker(cinfo, M_SOI);    /* first the SOI */
 524
 525   /* SOI is defined to reset restart interval to 0 */
 526   marker->last_restart_interval = 0;
 527
 528   if (cinfo->write_JFIF_header) /* next an optional JFIF APP0 */
 529     emit_jfif_app0(cinfo);
 530   if (cinfo->write_Adobe_marker) /* next an optional Adobe APP14 */
 531     emit_adobe_app14(cinfo);
 532 }
 533
 534
 535 /*
 536  * Write frame header.
 537  * This consists of DQT and SOFn markers,
 538  * a conditional LSE marker and a conditional pseudo SOS marker.
 539  * Note that we do not emit the SOF until we have emitted the DQT(s).
 540  * This avoids compatibility problems with incorrect implementations that
 541  * try to error-check the quant table numbers as soon as they see the SOF.
 542  */
 543
 544 METHODDEF(void)
 545 write_frame_header (j_compress_ptr cinfo)
 546 {
 547   int ci, prec;
 548   boolean is_baseline;
 549   jpeg_component_info *compptr;
 550
 551   /* Emit DQT for each quantization table.
 552    * Note that emit_dqt() suppresses any duplicate tables.
 553    */
 554   prec = 0;
 555   for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
 556        ci++, compptr++) {
 557     prec += emit_dqt(cinfo, compptr->quant_tbl_no);
 558   }
 559   /* now prec is nonzero iff there are any 16-bit quant tables. */
 560
 561   /* Check for a non-baseline specification.
 562    * Note we assume that Huffman table numbers won't be changed later.
 563    */
 564   if (cinfo->arith_code || cinfo->progressive_mode ||
 565       cinfo->data_precision != 8 || cinfo->block_size != DCTSIZE) {
 566     is_baseline = FALSE;
 567   } else {
 568     is_baseline = TRUE;
 569     for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
 570          ci++, compptr++) {
 571       if (compptr->dc_tbl_no > 1 || compptr->ac_tbl_no > 1)
 572         is_baseline = FALSE;
 573     }
 574     if (prec && is_baseline) {
 575       is_baseline = FALSE;
 576       /* If it's baseline except for quantizer size, warn the user */
 577       TRACEMS(cinfo, 0, JTRC_16BIT_TABLES);
 578     }
 579   }
 580
 581   /* Emit the proper SOF marker */
 582   if (cinfo->arith_code) {
 583     if (cinfo->progressive_mode)
 584       emit_sof(cinfo, M_SOF10); /* SOF code for progressive arithmetic */
 585     else
 586       emit_sof(cinfo, M_SOF9);  /* SOF code for sequential arithmetic */
 587   } else {
 588     if (cinfo->progressive_mode)
 589       emit_sof(cinfo, M_SOF2);  /* SOF code for progressive Huffman */
 590     else if (is_baseline)
 591       emit_sof(cinfo, M_SOF0);  /* SOF code for baseline implementation */
 592     else
 593       emit_sof(cinfo, M_SOF1);  /* SOF code for non-baseline Huffman file */
 594   }
 595
 596   /* Check to emit LSE inverse color transform specification marker */
 597   if (cinfo->color_transform)
 598     emit_lse_ict(cinfo);
 599
 600   /* Check to emit pseudo SOS marker */
 601   if (cinfo->progressive_mode && cinfo->block_size != DCTSIZE)
 602     emit_pseudo_sos(cinfo);
 603 }
 604
 605
 606 /*
 607  * Write scan header.
 608  * This consists of DHT or DAC markers, optional DRI, and SOS.
 609  * Compressed data will be written following the SOS.
 610  */
 611
 612 METHODDEF(void)
 613 write_scan_header (j_compress_ptr cinfo)
 614 {
 615   my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
 616   int i;
 617   jpeg_component_info *compptr;
 618
 619   if (cinfo->arith_code) {
 620     /* Emit arith conditioning info.  We may have some duplication
 621      * if the file has multiple scans, but it's so small it's hardly
 622      * worth worrying about.
 623      */
 624     emit_dac(cinfo);
 625   } else {
 626     /* Emit Huffman tables.
 627      * Note that emit_dht() suppresses any duplicate tables.
 628      */
 629     for (i = 0; i < cinfo->comps_in_scan; i++) {
 630       compptr = cinfo->cur_comp_info[i];
 631       /* DC needs no table for refinement scan */
 632       if (cinfo->Ss == 0 && cinfo->Ah == 0)
 633         emit_dht(cinfo, compptr->dc_tbl_no, FALSE);
 634       /* AC needs no table when not present */
 635       if (cinfo->Se)
 636         emit_dht(cinfo, compptr->ac_tbl_no, TRUE);
 637     }
 638   }
 639
 640   /* Emit DRI if required --- note that DRI value could change for each scan.
 641    * We avoid wasting space with unnecessary DRIs, however.
 642    */
 643   if (cinfo->restart_interval != marker->last_restart_interval) {
 644     emit_dri(cinfo);
 645     marker->last_restart_interval = cinfo->restart_interval;
 646   }
 647
 648   emit_sos(cinfo);
 649 }
 650
 651
 652 /*
 653  * Write datastream trailer.
 654  */
 655
 656 METHODDEF(void)
 657 write_file_trailer (j_compress_ptr cinfo)
 658 {
 659   emit_marker(cinfo, M_EOI);
 660 }
 661
 662
 663 /*
 664  * Write an abbreviated table-specification datastream.
 665  * This consists of SOI, DQT and DHT tables, and EOI.
 666  * Any table that is defined and not marked sent_table = TRUE will be
 667  * emitted.  Note that all tables will be marked sent_table = TRUE at exit.
 668  */
 669
 670 METHODDEF(void)
 671 write_tables_only (j_compress_ptr cinfo)
 672 {
 673   int i;
 674
 675   emit_marker(cinfo, M_SOI);
 676
 677   for (i = 0; i < NUM_QUANT_TBLS; i++) {
 678     if (cinfo->quant_tbl_ptrs[i] != NULL)
 679       (void) emit_dqt(cinfo, i);
 680   }
 681
 682   if (! cinfo->arith_code) {
 683     for (i = 0; i < NUM_HUFF_TBLS; i++) {
 684       if (cinfo->dc_huff_tbl_ptrs[i] != NULL)
 685         emit_dht(cinfo, i, FALSE);
 686       if (cinfo->ac_huff_tbl_ptrs[i] != NULL)
 687         emit_dht(cinfo, i, TRUE);
 688     }
 689   }
 690
 691   emit_marker(cinfo, M_EOI);
 692 }
 693
 694
 695 /*
 696  * Initialize the marker writer module.
 697  */
 698
 699 GLOBAL(void)
 700 jinit_marker_writer (j_compress_ptr cinfo)
 701 {
 702   my_marker_ptr marker;
 703
 704   /* Create the subobject */
 705   marker = (my_marker_ptr)
 706     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
 707                                 SIZEOF(my_marker_writer));
 708   cinfo->marker = &marker->pub;
 709   /* Initialize method pointers */
 710   marker->pub.write_file_header = write_file_header;
 711   marker->pub.write_frame_header = write_frame_header;
 712   marker->pub.write_scan_header = write_scan_header;
 713   marker->pub.write_file_trailer = write_file_trailer;
 714   marker->pub.write_tables_only = write_tables_only;
 715   marker->pub.write_marker_header = write_marker_header;
 716   marker->pub.write_marker_byte = write_marker_byte;
 717   /* Initialize private state */
 718   marker->last_restart_interval = 0;
 719 }