1/*
2 * jcmarker.c
3 *
4 * Copyright (C) 1991-1998, Thomas G. Lane.
5 * Modified 2003-2009 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
17typedef 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_JPG13 = 0xfd,
77  M_COM   = 0xfe,
78
79  M_TEM   = 0x01,
80
81  M_ERROR = 0x100
82} JPEG_MARKER;
83
84
85/* Private state */
86
87typedef struct {
88  struct jpeg_marker_writer pub; /* public fields */
89
90  unsigned int last_restart_interval; /* last DRI value emitted; 0 after SOI */
91} my_marker_writer;
92
93typedef my_marker_writer * my_marker_ptr;
94
95
96/*
97 * Basic output routines.
98 *
99 * Note that we do not support suspension while writing a marker.
100 * Therefore, an application using suspension must ensure that there is
101 * enough buffer space for the initial markers (typ. 600-700 bytes) before
102 * calling jpeg_start_compress, and enough space to write the trailing EOI
103 * (a few bytes) before calling jpeg_finish_compress.  Multipass compression
104 * modes are not supported at all with suspension, so those two are the only
105 * points where markers will be written.
106 */
107
108LOCAL(void)
109emit_byte (j_compress_ptr cinfo, int val)
110/* Emit a byte */
111{
112  struct jpeg_destination_mgr * dest = cinfo->dest;
113
114  *(dest->next_output_byte)++ = (JOCTET) val;
115  if (--dest->free_in_buffer == 0) {
116    if (! (*dest->empty_output_buffer) (cinfo))
117      ERREXIT(cinfo, JERR_CANT_SUSPEND);
118  }
119}
120
121
122LOCAL(void)
123emit_marker (j_compress_ptr cinfo, JPEG_MARKER mark)
124/* Emit a marker code */
125{
126  emit_byte(cinfo, 0xFF);
127  emit_byte(cinfo, (int) mark);
128}
129
130
131LOCAL(void)
132emit_2bytes (j_compress_ptr cinfo, int value)
133/* Emit a 2-byte integer; these are always MSB first in JPEG files */
134{
135  emit_byte(cinfo, (value >> 8) & 0xFF);
136  emit_byte(cinfo, value & 0xFF);
137}
138
139
140/*
141 * Routines to write specific marker types.
142 */
143
144LOCAL(int)
145emit_dqt (j_compress_ptr cinfo, int index)
146/* Emit a DQT marker */
147/* Returns the precision used (0 = 8bits, 1 = 16bits) for baseline checking */
148{
149  JQUANT_TBL * qtbl = cinfo->quant_tbl_ptrs[index];
150  int prec;
151  int i;
152
153  if (qtbl == NULL)
154    ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, index);
155
156  prec = 0;
157  for (i = 0; i <= cinfo->lim_Se; i++) {
158    if (qtbl->quantval[cinfo->natural_order[i]] > 255)
159      prec = 1;
160  }
161
162  if (! qtbl->sent_table) {
163    emit_marker(cinfo, M_DQT);
164
165    emit_2bytes(cinfo,
166      prec ? cinfo->lim_Se * 2 + 2 + 1 + 2 : cinfo->lim_Se + 1 + 1 + 2);
167
168    emit_byte(cinfo, index + (prec<<4));
169
170    for (i = 0; i <= cinfo->lim_Se; i++) {
171      /* The table entries must be emitted in zigzag order. */
172      unsigned int qval = qtbl->quantval[cinfo->natural_order[i]];
173      if (prec)
174	emit_byte(cinfo, (int) (qval >> 8));
175      emit_byte(cinfo, (int) (qval & 0xFF));
176    }
177
178    qtbl->sent_table = TRUE;
179  }
180
181  return prec;
182}
183
184
185LOCAL(void)
186emit_dht (j_compress_ptr cinfo, int index, boolean is_ac)
187/* Emit a DHT marker */
188{
189  JHUFF_TBL * htbl;
190  int length, i;
191
192  if (is_ac) {
193    htbl = cinfo->ac_huff_tbl_ptrs[index];
194    index += 0x10;		/* output index has AC bit set */
195  } else {
196    htbl = cinfo->dc_huff_tbl_ptrs[index];
197  }
198
199  if (htbl == NULL)
200    ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, index);
201
202  if (! htbl->sent_table) {
203    emit_marker(cinfo, M_DHT);
204
205    length = 0;
206    for (i = 1; i <= 16; i++)
207      length += htbl->bits[i];
208
209    emit_2bytes(cinfo, length + 2 + 1 + 16);
210    emit_byte(cinfo, index);
211
212    for (i = 1; i <= 16; i++)
213      emit_byte(cinfo, htbl->bits[i]);
214
215    for (i = 0; i < length; i++)
216      emit_byte(cinfo, htbl->huffval[i]);
217
218    htbl->sent_table = TRUE;
219  }
220}
221
222
223LOCAL(void)
224emit_dac (j_compress_ptr cinfo)
225/* Emit a DAC marker */
226/* Since the useful info is so small, we want to emit all the tables in */
227/* one DAC marker.  Therefore this routine does its own scan of the table. */
228{
229#ifdef C_ARITH_CODING_SUPPORTED
230  char dc_in_use[NUM_ARITH_TBLS];
231  char ac_in_use[NUM_ARITH_TBLS];
232  int length, i;
233  jpeg_component_info *compptr;
234
235  for (i = 0; i < NUM_ARITH_TBLS; i++)
236    dc_in_use[i] = ac_in_use[i] = 0;
237
238  for (i = 0; i < cinfo->comps_in_scan; i++) {
239    compptr = cinfo->cur_comp_info[i];
240    /* DC needs no table for refinement scan */
241    if (cinfo->Ss == 0 && cinfo->Ah == 0)
242      dc_in_use[compptr->dc_tbl_no] = 1;
243    /* AC needs no table when not present */
244    if (cinfo->Se)
245      ac_in_use[compptr->ac_tbl_no] = 1;
246  }
247
248  length = 0;
249  for (i = 0; i < NUM_ARITH_TBLS; i++)
250    length += dc_in_use[i] + ac_in_use[i];
251
252  emit_marker(cinfo, M_DAC);
253
254  emit_2bytes(cinfo, length*2 + 2);
255
256  for (i = 0; i < NUM_ARITH_TBLS; i++) {
257    if (dc_in_use[i]) {
258      emit_byte(cinfo, i);
259      emit_byte(cinfo, cinfo->arith_dc_L[i] + (cinfo->arith_dc_U[i]<<4));
260    }
261    if (ac_in_use[i]) {
262      emit_byte(cinfo, i + 0x10);
263      emit_byte(cinfo, cinfo->arith_ac_K[i]);
264    }
265  }
266#endif /* C_ARITH_CODING_SUPPORTED */
267}
268
269
270LOCAL(void)
271emit_dri (j_compress_ptr cinfo)
272/* Emit a DRI marker */
273{
274  emit_marker(cinfo, M_DRI);
275
276  emit_2bytes(cinfo, 4);	/* fixed length */
277
278  emit_2bytes(cinfo, (int) cinfo->restart_interval);
279}
280
281
282LOCAL(void)
283emit_sof (j_compress_ptr cinfo, JPEG_MARKER code)
284/* Emit a SOF marker */
285{
286  int ci;
287  jpeg_component_info *compptr;
288
289  emit_marker(cinfo, code);
290
291  emit_2bytes(cinfo, 3 * cinfo->num_components + 2 + 5 + 1); /* length */
292
293  /* Make sure image isn't bigger than SOF field can handle */
294  if ((long) cinfo->jpeg_height > 65535L ||
295      (long) cinfo->jpeg_width > 65535L)
296    ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) 65535);
297
298  emit_byte(cinfo, cinfo->data_precision);
299  emit_2bytes(cinfo, (int) cinfo->jpeg_height);
300  emit_2bytes(cinfo, (int) cinfo->jpeg_width);
301
302  emit_byte(cinfo, cinfo->num_components);
303
304  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
305       ci++, compptr++) {
306    emit_byte(cinfo, compptr->component_id);
307    emit_byte(cinfo, (compptr->h_samp_factor << 4) + compptr->v_samp_factor);
308    emit_byte(cinfo, compptr->quant_tbl_no);
309  }
310}
311
312
313LOCAL(void)
314emit_sos (j_compress_ptr cinfo)
315/* Emit a SOS marker */
316{
317  int i, td, ta;
318  jpeg_component_info *compptr;
319
320  emit_marker(cinfo, M_SOS);
321
322  emit_2bytes(cinfo, 2 * cinfo->comps_in_scan + 2 + 1 + 3); /* length */
323
324  emit_byte(cinfo, cinfo->comps_in_scan);
325
326  for (i = 0; i < cinfo->comps_in_scan; i++) {
327    compptr = cinfo->cur_comp_info[i];
328    emit_byte(cinfo, compptr->component_id);
329
330    /* We emit 0 for unused field(s); this is recommended by the P&M text
331     * but does not seem to be specified in the standard.
332     */
333
334    /* DC needs no table for refinement scan */
335    td = cinfo->Ss == 0 && cinfo->Ah == 0 ? compptr->dc_tbl_no : 0;
336    /* AC needs no table when not present */
337    ta = cinfo->Se ? compptr->ac_tbl_no : 0;
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_pseudo_sos (j_compress_ptr cinfo)
350/* Emit a pseudo SOS marker */
351{
352  emit_marker(cinfo, M_SOS);
353
354  emit_2bytes(cinfo, 2 + 1 + 3); /* length */
355
356  emit_byte(cinfo, 0); /* Ns */
357
358  emit_byte(cinfo, 0); /* Ss */
359  emit_byte(cinfo, cinfo->block_size * cinfo->block_size - 1); /* Se */
360  emit_byte(cinfo, 0); /* Ah/Al */
361}
362
363
364LOCAL(void)
365emit_jfif_app0 (j_compress_ptr cinfo)
366/* Emit a JFIF-compliant APP0 marker */
367{
368  /*
369   * Length of APP0 block	(2 bytes)
370   * Block ID			(4 bytes - ASCII "JFIF")
371   * Zero byte			(1 byte to terminate the ID string)
372   * Version Major, Minor	(2 bytes - major first)
373   * Units			(1 byte - 0x00 = none, 0x01 = inch, 0x02 = cm)
374   * Xdpu			(2 bytes - dots per unit horizontal)
375   * Ydpu			(2 bytes - dots per unit vertical)
376   * Thumbnail X size		(1 byte)
377   * Thumbnail Y size		(1 byte)
378   */
379
380  emit_marker(cinfo, M_APP0);
381
382  emit_2bytes(cinfo, 2 + 4 + 1 + 2 + 1 + 2 + 2 + 1 + 1); /* length */
383
384  emit_byte(cinfo, 0x4A);	/* Identifier: ASCII "JFIF" */
385  emit_byte(cinfo, 0x46);
386  emit_byte(cinfo, 0x49);
387  emit_byte(cinfo, 0x46);
388  emit_byte(cinfo, 0);
389  emit_byte(cinfo, cinfo->JFIF_major_version); /* Version fields */
390  emit_byte(cinfo, cinfo->JFIF_minor_version);
391  emit_byte(cinfo, cinfo->density_unit); /* Pixel size information */
392  emit_2bytes(cinfo, (int) cinfo->X_density);
393  emit_2bytes(cinfo, (int) cinfo->Y_density);
394  emit_byte(cinfo, 0);		/* No thumbnail image */
395  emit_byte(cinfo, 0);
396}
397
398
399LOCAL(void)
400emit_adobe_app14 (j_compress_ptr cinfo)
401/* Emit an Adobe APP14 marker */
402{
403  /*
404   * Length of APP14 block	(2 bytes)
405   * Block ID			(5 bytes - ASCII "Adobe")
406   * Version Number		(2 bytes - currently 100)
407   * Flags0			(2 bytes - currently 0)
408   * Flags1			(2 bytes - currently 0)
409   * Color transform		(1 byte)
410   *
411   * Although Adobe TN 5116 mentions Version = 101, all the Adobe files
412   * now in circulation seem to use Version = 100, so that's what we write.
413   *
414   * We write the color transform byte as 1 if the JPEG color space is
415   * YCbCr, 2 if it's YCCK, 0 otherwise.  Adobe's definition has to do with
416   * whether the encoder performed a transformation, which is pretty useless.
417   */
418
419  emit_marker(cinfo, M_APP14);
420
421  emit_2bytes(cinfo, 2 + 5 + 2 + 2 + 2 + 1); /* length */
422
423  emit_byte(cinfo, 0x41);	/* Identifier: ASCII "Adobe" */
424  emit_byte(cinfo, 0x64);
425  emit_byte(cinfo, 0x6F);
426  emit_byte(cinfo, 0x62);
427  emit_byte(cinfo, 0x65);
428  emit_2bytes(cinfo, 100);	/* Version */
429  emit_2bytes(cinfo, 0);	/* Flags0 */
430  emit_2bytes(cinfo, 0);	/* Flags1 */
431  switch (cinfo->jpeg_color_space) {
432  case JCS_YCbCr:
433    emit_byte(cinfo, 1);	/* Color transform = 1 */
434    break;
435  case JCS_YCCK:
436    emit_byte(cinfo, 2);	/* Color transform = 2 */
437    break;
438  default:
439    emit_byte(cinfo, 0);	/* Color transform = 0 */
440    break;
441  }
442}
443
444
445/*
446 * These routines allow writing an arbitrary marker with parameters.
447 * The only intended use is to emit COM or APPn markers after calling
448 * write_file_header and before calling write_frame_header.
449 * Other uses are not guaranteed to produce desirable results.
450 * Counting the parameter bytes properly is the caller's responsibility.
451 */
452
453METHODDEF(void)
454write_marker_header (j_compress_ptr cinfo, int marker, unsigned int datalen)
455/* Emit an arbitrary marker header */
456{
457  if (datalen > (unsigned int) 65533)		/* safety check */
458    ERREXIT(cinfo, JERR_BAD_LENGTH);
459
460  emit_marker(cinfo, (JPEG_MARKER) marker);
461
462  emit_2bytes(cinfo, (int) (datalen + 2));	/* total length */
463}
464
465METHODDEF(void)
466write_marker_byte (j_compress_ptr cinfo, int val)
467/* Emit one byte of marker parameters following write_marker_header */
468{
469  emit_byte(cinfo, val);
470}
471
472
473/*
474 * Write datastream header.
475 * This consists of an SOI and optional APPn markers.
476 * We recommend use of the JFIF marker, but not the Adobe marker,
477 * when using YCbCr or grayscale data.  The JFIF marker should NOT
478 * be used for any other JPEG colorspace.  The Adobe marker is helpful
479 * to distinguish RGB, CMYK, and YCCK colorspaces.
480 * Note that an application can write additional header markers after
481 * jpeg_start_compress returns.
482 */
483
484METHODDEF(void)
485write_file_header (j_compress_ptr cinfo)
486{
487  my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
488
489  emit_marker(cinfo, M_SOI);	/* first the SOI */
490
491  /* SOI is defined to reset restart interval to 0 */
492  marker->last_restart_interval = 0;
493
494  if (cinfo->write_JFIF_header)	/* next an optional JFIF APP0 */
495    emit_jfif_app0(cinfo);
496  if (cinfo->write_Adobe_marker) /* next an optional Adobe APP14 */
497    emit_adobe_app14(cinfo);
498}
499
500
501/*
502 * Write frame header.
503 * This consists of DQT and SOFn markers, and a conditional pseudo SOS marker.
504 * Note that we do not emit the SOF until we have emitted the DQT(s).
505 * This avoids compatibility problems with incorrect implementations that
506 * try to error-check the quant table numbers as soon as they see the SOF.
507 */
508
509METHODDEF(void)
510write_frame_header (j_compress_ptr cinfo)
511{
512  int ci, prec;
513  boolean is_baseline;
514  jpeg_component_info *compptr;
515
516  /* Emit DQT for each quantization table.
517   * Note that emit_dqt() suppresses any duplicate tables.
518   */
519  prec = 0;
520  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
521       ci++, compptr++) {
522    prec += emit_dqt(cinfo, compptr->quant_tbl_no);
523  }
524  /* now prec is nonzero iff there are any 16-bit quant tables. */
525
526  /* Check for a non-baseline specification.
527   * Note we assume that Huffman table numbers won't be changed later.
528   */
529  if (cinfo->arith_code || cinfo->progressive_mode ||
530      cinfo->data_precision != 8 || cinfo->block_size != DCTSIZE) {
531    is_baseline = FALSE;
532  } else {
533    is_baseline = TRUE;
534    for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
535	 ci++, compptr++) {
536      if (compptr->dc_tbl_no > 1 || compptr->ac_tbl_no > 1)
537	is_baseline = FALSE;
538    }
539    if (prec && is_baseline) {
540      is_baseline = FALSE;
541      /* If it's baseline except for quantizer size, warn the user */
542      TRACEMS(cinfo, 0, JTRC_16BIT_TABLES);
543    }
544  }
545
546  /* Emit the proper SOF marker */
547  if (cinfo->arith_code) {
548    if (cinfo->progressive_mode)
549      emit_sof(cinfo, M_SOF10); /* SOF code for progressive arithmetic */
550    else
551      emit_sof(cinfo, M_SOF9);  /* SOF code for sequential arithmetic */
552  } else {
553    if (cinfo->progressive_mode)
554      emit_sof(cinfo, M_SOF2);	/* SOF code for progressive Huffman */
555    else if (is_baseline)
556      emit_sof(cinfo, M_SOF0);	/* SOF code for baseline implementation */
557    else
558      emit_sof(cinfo, M_SOF1);	/* SOF code for non-baseline Huffman file */
559  }
560
561  /* Check to emit pseudo SOS marker */
562  if (cinfo->progressive_mode && cinfo->block_size != DCTSIZE)
563    emit_pseudo_sos(cinfo);
564}
565
566
567/*
568 * Write scan header.
569 * This consists of DHT or DAC markers, optional DRI, and SOS.
570 * Compressed data will be written following the SOS.
571 */
572
573METHODDEF(void)
574write_scan_header (j_compress_ptr cinfo)
575{
576  my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
577  int i;
578  jpeg_component_info *compptr;
579
580  if (cinfo->arith_code) {
581    /* Emit arith conditioning info.  We may have some duplication
582     * if the file has multiple scans, but it's so small it's hardly
583     * worth worrying about.
584     */
585    emit_dac(cinfo);
586  } else {
587    /* Emit Huffman tables.
588     * Note that emit_dht() suppresses any duplicate tables.
589     */
590    for (i = 0; i < cinfo->comps_in_scan; i++) {
591      compptr = cinfo->cur_comp_info[i];
592      /* DC needs no table for refinement scan */
593      if (cinfo->Ss == 0 && cinfo->Ah == 0)
594	emit_dht(cinfo, compptr->dc_tbl_no, FALSE);
595      /* AC needs no table when not present */
596      if (cinfo->Se)
597	emit_dht(cinfo, compptr->ac_tbl_no, TRUE);
598    }
599  }
600
601  /* Emit DRI if required --- note that DRI value could change for each scan.
602   * We avoid wasting space with unnecessary DRIs, however.
603   */
604  if (cinfo->restart_interval != marker->last_restart_interval) {
605    emit_dri(cinfo);
606    marker->last_restart_interval = cinfo->restart_interval;
607  }
608
609  emit_sos(cinfo);
610}
611
612
613/*
614 * Write datastream trailer.
615 */
616
617METHODDEF(void)
618write_file_trailer (j_compress_ptr cinfo)
619{
620  emit_marker(cinfo, M_EOI);
621}
622
623
624/*
625 * Write an abbreviated table-specification datastream.
626 * This consists of SOI, DQT and DHT tables, and EOI.
627 * Any table that is defined and not marked sent_table = TRUE will be
628 * emitted.  Note that all tables will be marked sent_table = TRUE at exit.
629 */
630
631METHODDEF(void)
632write_tables_only (j_compress_ptr cinfo)
633{
634  int i;
635
636  emit_marker(cinfo, M_SOI);
637
638  for (i = 0; i < NUM_QUANT_TBLS; i++) {
639    if (cinfo->quant_tbl_ptrs[i] != NULL)
640      (void) emit_dqt(cinfo, i);
641  }
642
643  if (! cinfo->arith_code) {
644    for (i = 0; i < NUM_HUFF_TBLS; i++) {
645      if (cinfo->dc_huff_tbl_ptrs[i] != NULL)
646	emit_dht(cinfo, i, FALSE);
647      if (cinfo->ac_huff_tbl_ptrs[i] != NULL)
648	emit_dht(cinfo, i, TRUE);
649    }
650  }
651
652  emit_marker(cinfo, M_EOI);
653}
654
655
656/*
657 * Initialize the marker writer module.
658 */
659
660GLOBAL(void)
661jinit_marker_writer (j_compress_ptr cinfo)
662{
663  my_marker_ptr marker;
664
665  /* Create the subobject */
666  marker = (my_marker_ptr)
667    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
668				SIZEOF(my_marker_writer));
669  cinfo->marker = (struct jpeg_marker_writer *) marker;
670  /* Initialize method pointers */
671  marker->pub.write_file_header = write_file_header;
672  marker->pub.write_frame_header = write_frame_header;
673  marker->pub.write_scan_header = write_scan_header;
674  marker->pub.write_file_trailer = write_file_trailer;
675  marker->pub.write_tables_only = write_tables_only;
676  marker->pub.write_marker_header = write_marker_header;
677  marker->pub.write_marker_byte = write_marker_byte;
678  /* Initialize private state */
679  marker->last_restart_interval = 0;
680}
681