1 /*
2 * jcmarker.c
3 *
4 * Copyright (C) 1991-1994, 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 /*
85 * Basic output routines.
86 *
87 * Note that we do not support suspension while writing a marker.
88 * Therefore, an application using suspension must ensure that there is
89 * enough buffer space for the initial markers (typ. 600-700 bytes) before
90 * calling jpeg_start_compress, and enough space to write the trailing EOI
91 * (a few bytes) before calling jpeg_finish_compress. Multipass compression
92 * modes are not supported at all with suspension, so those two are the only
93 * points where markers will be written.
94 */
95
96 LOCAL void
emit_byte(j_compress_ptr cinfo,int val)97 emit_byte (j_compress_ptr cinfo, int val)
98 /* Emit a byte */
99 {
100 struct jpeg_destination_mgr * dest = cinfo->dest;
101
102 *(dest->next_output_byte)++ = (JOCTET) val;
103 if (--dest->free_in_buffer == 0) {
104 if (! (*dest->empty_output_buffer) (cinfo))
105 ERREXIT(cinfo, JERR_CANT_SUSPEND);
106 }
107 }
108
109
110 LOCAL void
emit_marker(j_compress_ptr cinfo,JPEG_MARKER mark)111 emit_marker (j_compress_ptr cinfo, JPEG_MARKER mark)
112 /* Emit a marker code */
113 {
114 emit_byte(cinfo, 0xFF);
115 emit_byte(cinfo, (int) mark);
116 }
117
118
119 LOCAL void
emit_2bytes(j_compress_ptr cinfo,int value)120 emit_2bytes (j_compress_ptr cinfo, int value)
121 /* Emit a 2-byte integer; these are always MSB first in JPEG files */
122 {
123 emit_byte(cinfo, (value >> 8) & 0xFF);
124 emit_byte(cinfo, value & 0xFF);
125 }
126
127
128 /*
129 * Routines to write specific marker types.
130 */
131
132 LOCAL int
emit_dqt(j_compress_ptr cinfo,int index)133 emit_dqt (j_compress_ptr cinfo, int index)
134 /* Emit a DQT marker */
135 /* Returns the precision used (0 = 8bits, 1 = 16bits) for baseline checking */
136 {
137 JQUANT_TBL * qtbl = cinfo->quant_tbl_ptrs[index];
138 int prec;
139 int i;
140
141 if (qtbl == NULL)
142 ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, index);
143
144 prec = 0;
145 for (i = 0; i < DCTSIZE2; i++) {
146 if (qtbl->quantval[i] > 255)
147 prec = 1;
148 }
149
150 if (! qtbl->sent_table) {
151 emit_marker(cinfo, M_DQT);
152
153 emit_2bytes(cinfo, prec ? DCTSIZE2*2 + 1 + 2 : DCTSIZE2 + 1 + 2);
154
155 emit_byte(cinfo, index + (prec<<4));
156
157 for (i = 0; i < DCTSIZE2; i++) {
158 if (prec)
159 emit_byte(cinfo, qtbl->quantval[i] >> 8);
160 emit_byte(cinfo, qtbl->quantval[i] & 0xFF);
161 }
162
163 qtbl->sent_table = TRUE;
164 }
165
166 return prec;
167 }
168
169
170 LOCAL void
emit_dht(j_compress_ptr cinfo,int index,boolean is_ac)171 emit_dht (j_compress_ptr cinfo, int index, boolean is_ac)
172 /* Emit a DHT marker */
173 {
174 JHUFF_TBL * htbl;
175 int length, i;
176
177 if (is_ac) {
178 htbl = cinfo->ac_huff_tbl_ptrs[index];
179 index += 0x10; /* output index has AC bit set */
180 } else {
181 htbl = cinfo->dc_huff_tbl_ptrs[index];
182 }
183
184 if (htbl == NULL)
185 ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, index);
186
187 if (! htbl->sent_table) {
188 emit_marker(cinfo, M_DHT);
189
190 length = 0;
191 for (i = 1; i <= 16; i++)
192 length += htbl->bits[i];
193
194 emit_2bytes(cinfo, length + 2 + 1 + 16);
195 emit_byte(cinfo, index);
196
197 for (i = 1; i <= 16; i++)
198 emit_byte(cinfo, htbl->bits[i]);
199
200 for (i = 0; i < length; i++)
201 emit_byte(cinfo, htbl->huffval[i]);
202
203 htbl->sent_table = TRUE;
204 }
205 }
206
207
208 LOCAL void
emit_dac(j_compress_ptr cinfo)209 emit_dac (j_compress_ptr cinfo)
210 /* Emit a DAC marker */
211 /* Since the useful info is so small, we want to emit all the tables in */
212 /* one DAC marker. Therefore this routine does its own scan of the table. */
213 {
214 #ifdef C_ARITH_CODING_SUPPORTED
215 char dc_in_use[NUM_ARITH_TBLS];
216 char ac_in_use[NUM_ARITH_TBLS];
217 int length, i;
218 jpeg_component_info *compptr;
219
220 for (i = 0; i < NUM_ARITH_TBLS; i++)
221 dc_in_use[i] = ac_in_use[i] = 0;
222
223 for (i = 0; i < cinfo->comps_in_scan; i++) {
224 compptr = cinfo->cur_comp_info[i];
225 dc_in_use[compptr->dc_tbl_no] = 1;
226 ac_in_use[compptr->ac_tbl_no] = 1;
227 }
228
229 length = 0;
230 for (i = 0; i < NUM_ARITH_TBLS; i++)
231 length += dc_in_use[i] + ac_in_use[i];
232
233 emit_marker(cinfo, M_DAC);
234
235 emit_2bytes(cinfo, length*2 + 2);
236
237 for (i = 0; i < NUM_ARITH_TBLS; i++) {
238 if (dc_in_use[i]) {
239 emit_byte(cinfo, i);
240 emit_byte(cinfo, cinfo->arith_dc_L[i] + (cinfo->arith_dc_U[i]<<4));
241 }
242 if (ac_in_use[i]) {
243 emit_byte(cinfo, i + 0x10);
244 emit_byte(cinfo, cinfo->arith_ac_K[i]);
245 }
246 }
247 #endif /* C_ARITH_CODING_SUPPORTED */
248 }
249
250
251 LOCAL void
emit_dri(j_compress_ptr cinfo)252 emit_dri (j_compress_ptr cinfo)
253 /* Emit a DRI marker */
254 {
255 emit_marker(cinfo, M_DRI);
256
257 emit_2bytes(cinfo, 4); /* fixed length */
258
259 emit_2bytes(cinfo, (int) cinfo->restart_interval);
260 }
261
262
263 LOCAL void
emit_sof(j_compress_ptr cinfo,JPEG_MARKER code)264 emit_sof (j_compress_ptr cinfo, JPEG_MARKER code)
265 /* Emit a SOF marker */
266 {
267 int ci;
268 jpeg_component_info *compptr;
269
270 emit_marker(cinfo, code);
271
272 emit_2bytes(cinfo, 3 * cinfo->num_components + 2 + 5 + 1); /* length */
273
274 /* Make sure image isn't bigger than SOF field can handle */
275 if ((long) cinfo->image_height > 65535L ||
276 (long) cinfo->image_width > 65535L)
277 ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) 65535);
278
279 emit_byte(cinfo, cinfo->data_precision);
280 emit_2bytes(cinfo, (int) cinfo->image_height);
281 emit_2bytes(cinfo, (int) cinfo->image_width);
282
283 emit_byte(cinfo, cinfo->num_components);
284
285 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
286 ci++, compptr++) {
287 emit_byte(cinfo, compptr->component_id);
288 emit_byte(cinfo, (compptr->h_samp_factor << 4) + compptr->v_samp_factor);
289 emit_byte(cinfo, compptr->quant_tbl_no);
290 }
291 }
292
293
294 LOCAL void
emit_sos(j_compress_ptr cinfo)295 emit_sos (j_compress_ptr cinfo)
296 /* Emit a SOS marker */
297 {
298 int i;
299 jpeg_component_info *compptr;
300
301 emit_marker(cinfo, M_SOS);
302
303 emit_2bytes(cinfo, 2 * cinfo->comps_in_scan + 2 + 1 + 3); /* length */
304
305 emit_byte(cinfo, cinfo->comps_in_scan);
306
307 for (i = 0; i < cinfo->comps_in_scan; i++) {
308 compptr = cinfo->cur_comp_info[i];
309 emit_byte(cinfo, compptr->component_id);
310 emit_byte(cinfo, (compptr->dc_tbl_no << 4) + compptr->ac_tbl_no);
311 }
312
313 emit_byte(cinfo, 0); /* Spectral selection start */
314 emit_byte(cinfo, DCTSIZE2-1); /* Spectral selection end */
315 emit_byte(cinfo, 0); /* Successive approximation */
316 }
317
318
319 LOCAL void
emit_jfif_app0(j_compress_ptr cinfo)320 emit_jfif_app0 (j_compress_ptr cinfo)
321 /* Emit a JFIF-compliant APP0 marker */
322 {
323 /*
324 * Length of APP0 block (2 bytes)
325 * Block ID (4 bytes - ASCII "JFIF")
326 * Zero byte (1 byte to terminate the ID string)
327 * Version Major, Minor (2 bytes - 0x01, 0x01)
328 * Units (1 byte - 0x00 = none, 0x01 = inch, 0x02 = cm)
329 * Xdpu (2 bytes - dots per unit horizontal)
330 * Ydpu (2 bytes - dots per unit vertical)
331 * Thumbnail X size (1 byte)
332 * Thumbnail Y size (1 byte)
333 */
334
335 emit_marker(cinfo, M_APP0);
336
337 emit_2bytes(cinfo, 2 + 4 + 1 + 2 + 1 + 2 + 2 + 1 + 1); /* length */
338
339 emit_byte(cinfo, 0x4A); /* Identifier: ASCII "JFIF" */
340 emit_byte(cinfo, 0x46);
341 emit_byte(cinfo, 0x49);
342 emit_byte(cinfo, 0x46);
343 emit_byte(cinfo, 0);
344 /* We currently emit version code 1.01 since we use no 1.02 features.
345 * This may avoid complaints from some older decoders.
346 */
347 emit_byte(cinfo, 1); /* Major version */
348 emit_byte(cinfo, 1); /* Minor version */
349 emit_byte(cinfo, cinfo->density_unit); /* Pixel size information */
350 emit_2bytes(cinfo, (int) cinfo->X_density);
351 emit_2bytes(cinfo, (int) cinfo->Y_density);
352 emit_byte(cinfo, 0); /* No thumbnail image */
353 emit_byte(cinfo, 0);
354 }
355
356
357 LOCAL void
emit_adobe_app14(j_compress_ptr cinfo)358 emit_adobe_app14 (j_compress_ptr cinfo)
359 /* Emit an Adobe APP14 marker */
360 {
361 /*
362 * Length of APP14 block (2 bytes)
363 * Block ID (5 bytes - ASCII "Adobe")
364 * Version Number (2 bytes - currently 100)
365 * Flags0 (2 bytes - currently 0)
366 * Flags1 (2 bytes - currently 0)
367 * Color transform (1 byte)
368 *
369 * Although Adobe TN 5116 mentions Version = 101, all the Adobe files
370 * now in circulation seem to use Version = 100, so that's what we write.
371 *
372 * We write the color transform byte as 1 if the JPEG color space is
373 * YCbCr, 2 if it's YCCK, 0 otherwise. Adobe's definition has to do with
374 * whether the encoder performed a transformation, which is pretty useless.
375 */
376
377 emit_marker(cinfo, M_APP14);
378
379 emit_2bytes(cinfo, 2 + 5 + 2 + 2 + 2 + 1); /* length */
380
381 emit_byte(cinfo, 0x41); /* Identifier: ASCII "Adobe" */
382 emit_byte(cinfo, 0x64);
383 emit_byte(cinfo, 0x6F);
384 emit_byte(cinfo, 0x62);
385 emit_byte(cinfo, 0x65);
386 emit_2bytes(cinfo, 100); /* Version */
387 emit_2bytes(cinfo, 0); /* Flags0 */
388 emit_2bytes(cinfo, 0); /* Flags1 */
389 switch (cinfo->jpeg_color_space) {
390 case JCS_YCbCr:
391 emit_byte(cinfo, 1); /* Color transform = 1 */
392 break;
393 case JCS_YCCK:
394 emit_byte(cinfo, 2); /* Color transform = 2 */
395 break;
396 default:
397 emit_byte(cinfo, 0); /* Color transform = 0 */
398 break;
399 }
400 }
401
402
403 /*
404 * This routine is exported for possible use by applications.
405 * The intended use is to emit COM or APPn markers after calling
406 * jpeg_start_compress() and before the first jpeg_write_scanlines() call
407 * (hence, after write_file_header but before write_frame_header).
408 * Other uses are not guaranteed to produce desirable results.
409 */
410
411 METHODDEF void
write_any_marker(j_compress_ptr cinfo,int marker,const JOCTET * dataptr,unsigned int datalen)412 write_any_marker (j_compress_ptr cinfo, int marker,
413 const JOCTET *dataptr, unsigned int datalen)
414 /* Emit an arbitrary marker with parameters */
415 {
416 if (datalen <= (unsigned int) 65533) { /* safety check */
417 emit_marker(cinfo, (JPEG_MARKER) marker);
418
419 emit_2bytes(cinfo, (int) (datalen + 2)); /* total length */
420
421 while (datalen--) {
422 emit_byte(cinfo, *dataptr);
423 dataptr++;
424 }
425 }
426 }
427
428
429 /*
430 * Write datastream header.
431 * This consists of an SOI and optional APPn markers.
432 * We recommend use of the JFIF marker, but not the Adobe marker,
433 * when using YCbCr or grayscale data. The JFIF marker should NOT
434 * be used for any other JPEG colorspace. The Adobe marker is helpful
435 * to distinguish RGB, CMYK, and YCCK colorspaces.
436 * Note that an application can write additional header markers after
437 * jpeg_start_decompress returns.
438 */
439
440 METHODDEF void
write_file_header(j_compress_ptr cinfo)441 write_file_header (j_compress_ptr cinfo)
442 {
443 emit_marker(cinfo, M_SOI); /* first the SOI */
444
445 if (cinfo->write_JFIF_header) /* next an optional JFIF APP0 */
446 emit_jfif_app0(cinfo);
447 if (cinfo->write_Adobe_marker) /* next an optional Adobe APP14 */
448 emit_adobe_app14(cinfo);
449 }
450
451
452 /*
453 * Write frame header.
454 * This consists of DQT and SOFn markers.
455 * Note that we do not emit the SOF until we have emitted the DQT(s).
456 * This avoids compatibility problems with incorrect implementations that
457 * try to error-check the quant table numbers as soon as they see the SOF.
458 */
459
460 METHODDEF void
write_frame_header(j_compress_ptr cinfo)461 write_frame_header (j_compress_ptr cinfo)
462 {
463 int ci, prec;
464 boolean is_baseline;
465 jpeg_component_info *compptr;
466
467 /* Emit DQT for each quantization table.
468 * Note that emit_dqt() suppresses any duplicate tables.
469 */
470 prec = 0;
471 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
472 ci++, compptr++) {
473 prec += emit_dqt(cinfo, compptr->quant_tbl_no);
474 }
475 /* now prec is nonzero iff there are any 16-bit quant tables. */
476
477 /* Check for a non-baseline specification.
478 * Note we assume that Huffman table numbers won't be changed later.
479 */
480 is_baseline = TRUE;
481 if (cinfo->arith_code || (cinfo->data_precision != 8))
482 is_baseline = FALSE;
483 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
484 ci++, compptr++) {
485 if (compptr->dc_tbl_no > 1 || compptr->ac_tbl_no > 1)
486 is_baseline = FALSE;
487 }
488 if (prec && is_baseline) {
489 is_baseline = FALSE;
490 /* If it's baseline except for quantizer size, warn the user */
491 TRACEMS(cinfo, 0, JTRC_16BIT_TABLES);
492 }
493
494 /* Emit the proper SOF marker */
495 if (cinfo->arith_code)
496 emit_sof(cinfo, M_SOF9); /* SOF code for arithmetic coding */
497 else if (is_baseline)
498 emit_sof(cinfo, M_SOF0); /* SOF code for baseline implementation */
499 else
500 emit_sof(cinfo, M_SOF1); /* SOF code for non-baseline Huffman file */
501 }
502
503
504 /*
505 * Write scan header.
506 * This consists of DHT or DAC markers, optional DRI, and SOS.
507 * Compressed data will be written following the SOS.
508 */
509
510 METHODDEF void
write_scan_header(j_compress_ptr cinfo)511 write_scan_header (j_compress_ptr cinfo)
512 {
513 int i;
514 jpeg_component_info *compptr;
515
516 if (cinfo->arith_code) {
517 /* Emit arith conditioning info. We may have some duplication
518 * if the file has multiple scans, but it's so small it's hardly
519 * worth worrying about.
520 */
521 emit_dac(cinfo);
522 } else {
523 /* Emit Huffman tables.
524 * Note that emit_dht() suppresses any duplicate tables.
525 */
526 for (i = 0; i < cinfo->comps_in_scan; i++) {
527 compptr = cinfo->cur_comp_info[i];
528 emit_dht(cinfo, compptr->dc_tbl_no, FALSE);
529 emit_dht(cinfo, compptr->ac_tbl_no, TRUE);
530 }
531 }
532
533 /* Emit DRI if required --- note that DRI value could change for each scan.
534 * If it doesn't, a tiny amount of space is wasted in multiple-scan files.
535 * We assume DRI will never be nonzero for one scan and zero for a later one.
536 */
537 if (cinfo->restart_interval)
538 emit_dri(cinfo);
539
540 emit_sos(cinfo);
541 }
542
543
544 /*
545 * Write datastream trailer.
546 */
547
548 METHODDEF void
write_file_trailer(j_compress_ptr cinfo)549 write_file_trailer (j_compress_ptr cinfo)
550 {
551 emit_marker(cinfo, M_EOI);
552 }
553
554
555 /*
556 * Write an abbreviated table-specification datastream.
557 * This consists of SOI, DQT and DHT tables, and EOI.
558 * Any table that is defined and not marked sent_table = TRUE will be
559 * emitted. Note that all tables will be marked sent_table = TRUE at exit.
560 */
561
562 METHODDEF void
write_tables_only(j_compress_ptr cinfo)563 write_tables_only (j_compress_ptr cinfo)
564 {
565 int i;
566
567 emit_marker(cinfo, M_SOI);
568
569 for (i = 0; i < NUM_QUANT_TBLS; i++) {
570 if (cinfo->quant_tbl_ptrs[i] != NULL)
571 (void) emit_dqt(cinfo, i);
572 }
573
574 if (! cinfo->arith_code) {
575 for (i = 0; i < NUM_HUFF_TBLS; i++) {
576 if (cinfo->dc_huff_tbl_ptrs[i] != NULL)
577 emit_dht(cinfo, i, FALSE);
578 if (cinfo->ac_huff_tbl_ptrs[i] != NULL)
579 emit_dht(cinfo, i, TRUE);
580 }
581 }
582
583 emit_marker(cinfo, M_EOI);
584 }
585
586
587 /*
588 * Initialize the marker writer module.
589 */
590
591 GLOBAL void
jinit_marker_writer(j_compress_ptr cinfo)592 jinit_marker_writer (j_compress_ptr cinfo)
593 {
594 /* Create the subobject */
595 cinfo->marker = (struct jpeg_marker_writer *)
596 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
597 SIZEOF(struct jpeg_marker_writer));
598 /* Initialize method pointers */
599 cinfo->marker->write_any_marker = write_any_marker;
600 cinfo->marker->write_file_header = write_file_header;
601 cinfo->marker->write_frame_header = write_frame_header;
602 cinfo->marker->write_scan_header = write_scan_header;
603 cinfo->marker->write_file_trailer = write_file_trailer;
604 cinfo->marker->write_tables_only = write_tables_only;
605 }
606