source: trunk/libjpeg/jcmarker.c @ 81

Last change on this file since 81 was 15, checked in by Eugene Romanenko, 16 years ago

needed libs update

File size: 17.5 KB
Line 
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
16typedef 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
86typedef 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
92typedef 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
107LOCAL(void)
108emit_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
121LOCAL(void)
122emit_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
130LOCAL(void)
131emit_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
143LOCAL(int)
144emit_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
183LOCAL(void)
184emit_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
221LOCAL(void)
222emit_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
264LOCAL(void)
265emit_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
276LOCAL(void)
277emit_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
307LOCAL(void)
308emit_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
348LOCAL(void)
349emit_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
383LOCAL(void)
384emit_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
437METHODDEF(void)
438write_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
449METHODDEF(void)
450write_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
468METHODDEF(void)
469write_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
493METHODDEF(void)
494write_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
550METHODDEF(void)
551write_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
601METHODDEF(void)
602write_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
615METHODDEF(void)
616write_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
644GLOBAL(void)
645jinit_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}
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