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view 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 |
| parents | |
| children |
line source
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 */
11 #define JPEG_INTERNALS
12 #include "jinclude.h"
13 #include "jpeglib.h"
16 typedef enum { /* JPEG marker codes */
17 M_SOF0 = 0xc0,
18 M_SOF1 = 0xc1,
19 M_SOF2 = 0xc2,
20 M_SOF3 = 0xc3,
22 M_SOF5 = 0xc5,
23 M_SOF6 = 0xc6,
24 M_SOF7 = 0xc7,
26 M_JPG = 0xc8,
27 M_SOF9 = 0xc9,
28 M_SOF10 = 0xca,
29 M_SOF11 = 0xcb,
31 M_SOF13 = 0xcd,
32 M_SOF14 = 0xce,
33 M_SOF15 = 0xcf,
35 M_DHT = 0xc4,
37 M_DAC = 0xcc,
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,
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,
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,
74 M_JPG0 = 0xf0,
75 M_JPG13 = 0xfd,
76 M_COM = 0xfe,
78 M_TEM = 0x01,
80 M_ERROR = 0x100
81 } JPEG_MARKER;
84 /* Private state */
86 typedef struct {
87 struct jpeg_marker_writer pub; /* public fields */
89 unsigned int last_restart_interval; /* last DRI value emitted; 0 after SOI */
90 } my_marker_writer;
92 typedef my_marker_writer * my_marker_ptr;
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 */
107 LOCAL(void)
108 emit_byte (j_compress_ptr cinfo, int val)
109 /* Emit a byte */
110 {
111 struct jpeg_destination_mgr * dest = cinfo->dest;
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 }
121 LOCAL(void)
122 emit_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 }
130 LOCAL(void)
131 emit_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 }
139 /*
140 * Routines to write specific marker types.
141 */
143 LOCAL(int)
144 emit_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;
152 if (qtbl == NULL)
153 ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, index);
155 prec = 0;
156 for (i = 0; i < DCTSIZE2; i++) {
157 if (qtbl->quantval[i] > 255)
158 prec = 1;
159 }
161 if (! qtbl->sent_table) {
162 emit_marker(cinfo, M_DQT);
164 emit_2bytes(cinfo, prec ? DCTSIZE2*2 + 1 + 2 : DCTSIZE2 + 1 + 2);
166 emit_byte(cinfo, index + (prec<<4));
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 }
176 qtbl->sent_table = TRUE;
177 }
179 return prec;
180 }
183 LOCAL(void)
184 emit_dht (j_compress_ptr cinfo, int index, boolean is_ac)
185 /* Emit a DHT marker */
186 {
187 JHUFF_TBL * htbl;
188 int length, i;
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 }
197 if (htbl == NULL)
198 ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, index);
200 if (! htbl->sent_table) {
201 emit_marker(cinfo, M_DHT);
203 length = 0;
204 for (i = 1; i <= 16; i++)
205 length += htbl->bits[i];
207 emit_2bytes(cinfo, length + 2 + 1 + 16);
208 emit_byte(cinfo, index);
210 for (i = 1; i <= 16; i++)
211 emit_byte(cinfo, htbl->bits[i]);
213 for (i = 0; i < length; i++)
214 emit_byte(cinfo, htbl->huffval[i]);
216 htbl->sent_table = TRUE;
217 }
218 }
221 LOCAL(void)
222 emit_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;
233 for (i = 0; i < NUM_ARITH_TBLS; i++)
234 dc_in_use[i] = ac_in_use[i] = 0;
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 }
242 length = 0;
243 for (i = 0; i < NUM_ARITH_TBLS; i++)
244 length += dc_in_use[i] + ac_in_use[i];
246 emit_marker(cinfo, M_DAC);
248 emit_2bytes(cinfo, length*2 + 2);
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 }
264 LOCAL(void)
265 emit_dri (j_compress_ptr cinfo)
266 /* Emit a DRI marker */
267 {
268 emit_marker(cinfo, M_DRI);
270 emit_2bytes(cinfo, 4); /* fixed length */
272 emit_2bytes(cinfo, (int) cinfo->restart_interval);
273 }
276 LOCAL(void)
277 emit_sof (j_compress_ptr cinfo, JPEG_MARKER code)
278 /* Emit a SOF marker */
279 {
280 int ci;
281 jpeg_component_info *compptr;
283 emit_marker(cinfo, code);
285 emit_2bytes(cinfo, 3 * cinfo->num_components + 2 + 5 + 1); /* length */
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);
292 emit_byte(cinfo, cinfo->data_precision);
293 emit_2bytes(cinfo, (int) cinfo->image_height);
294 emit_2bytes(cinfo, (int) cinfo->image_width);
296 emit_byte(cinfo, cinfo->num_components);
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 }
307 LOCAL(void)
308 emit_sos (j_compress_ptr cinfo)
309 /* Emit a SOS marker */
310 {
311 int i, td, ta;
312 jpeg_component_info *compptr;
314 emit_marker(cinfo, M_SOS);
316 emit_2bytes(cinfo, 2 * cinfo->comps_in_scan + 2 + 1 + 3); /* length */
318 emit_byte(cinfo, cinfo->comps_in_scan);
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 }
342 emit_byte(cinfo, cinfo->Ss);
343 emit_byte(cinfo, cinfo->Se);
344 emit_byte(cinfo, (cinfo->Ah << 4) + cinfo->Al);
345 }
348 LOCAL(void)
349 emit_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 */
364 emit_marker(cinfo, M_APP0);
366 emit_2bytes(cinfo, 2 + 4 + 1 + 2 + 1 + 2 + 2 + 1 + 1); /* length */
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 }
383 LOCAL(void)
384 emit_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 */
403 emit_marker(cinfo, M_APP14);
405 emit_2bytes(cinfo, 2 + 5 + 2 + 2 + 2 + 1); /* length */
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 }
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 */
437 METHODDEF(void)
438 write_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);
444 emit_marker(cinfo, (JPEG_MARKER) marker);
446 emit_2bytes(cinfo, (int) (datalen + 2)); /* total length */
447 }
449 METHODDEF(void)
450 write_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 }
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 */
468 METHODDEF(void)
469 write_file_header (j_compress_ptr cinfo)
470 {
471 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
473 emit_marker(cinfo, M_SOI); /* first the SOI */
475 /* SOI is defined to reset restart interval to 0 */
476 marker->last_restart_interval = 0;
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 }
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 */
493 METHODDEF(void)
494 write_frame_header (j_compress_ptr cinfo)
495 {
496 int ci, prec;
497 boolean is_baseline;
498 jpeg_component_info *compptr;
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. */
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 }
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 }
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 */
550 METHODDEF(void)
551 write_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;
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 }
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 }
593 emit_sos(cinfo);
594 }
597 /*
598 * Write datastream trailer.
599 */
601 METHODDEF(void)
602 write_file_trailer (j_compress_ptr cinfo)
603 {
604 emit_marker(cinfo, M_EOI);
605 }
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 */
615 METHODDEF(void)
616 write_tables_only (j_compress_ptr cinfo)
617 {
618 int i;
620 emit_marker(cinfo, M_SOI);
622 for (i = 0; i < NUM_QUANT_TBLS; i++) {
623 if (cinfo->quant_tbl_ptrs[i] != NULL)
624 (void) emit_dqt(cinfo, i);
625 }
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 }
636 emit_marker(cinfo, M_EOI);
637 }
640 /*
641 * Initialize the marker writer module.
642 */
644 GLOBAL(void)
645 jinit_marker_writer (j_compress_ptr cinfo)
646 {
647 my_marker_ptr marker;
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 }