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.
9 * This file contains routines to write JPEG datastream markers.
12 #define JPEG_INTERNALS
17 typedef enum { /* JPEG marker codes */
88 struct jpeg_marker_writer pub; /* public fields */
90 unsigned int last_restart_interval; /* last DRI value emitted; 0 after SOI */
93 typedef my_marker_writer * my_marker_ptr;
97 * Basic output routines.
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.
109 emit_byte (j_compress_ptr cinfo, int val)
112 struct jpeg_destination_mgr * dest = cinfo->dest;
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);
123 emit_marker (j_compress_ptr cinfo, JPEG_MARKER mark)
124 /* Emit a marker code */
126 emit_byte(cinfo, 0xFF);
127 emit_byte(cinfo, (int) mark);
132 emit_2bytes (j_compress_ptr cinfo, int value)
133 /* Emit a 2-byte integer; these are always MSB first in JPEG files */
135 emit_byte(cinfo, (value >> 8) & 0xFF);
136 emit_byte(cinfo, value & 0xFF);
141 * Routines to write specific marker types.
145 emit_dqt (j_compress_ptr cinfo, int index)
146 /* Emit a DQT marker */
147 /* Returns the precision used (0 = 8bits, 1 = 16bits) for baseline checking */
149 JQUANT_TBL * qtbl = cinfo->quant_tbl_ptrs[index];
154 ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, index);
157 for (i = 0; i <= cinfo->lim_Se; i++) {
158 if (qtbl->quantval[cinfo->natural_order[i]] > 255)
162 if (! qtbl->sent_table) {
163 emit_marker(cinfo, M_DQT);
166 prec ? cinfo->lim_Se * 2 + 2 + 1 + 2 : cinfo->lim_Se + 1 + 1 + 2);
168 emit_byte(cinfo, index + (prec<<4));
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]];
174 emit_byte(cinfo, (int) (qval >> 8));
175 emit_byte(cinfo, (int) (qval & 0xFF));
178 qtbl->sent_table = TRUE;
186 emit_dht (j_compress_ptr cinfo, int index, boolean is_ac)
187 /* Emit a DHT marker */
193 htbl = cinfo->ac_huff_tbl_ptrs[index];
194 index += 0x10; /* output index has AC bit set */
196 htbl = cinfo->dc_huff_tbl_ptrs[index];
200 ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, index);
202 if (! htbl->sent_table) {
203 emit_marker(cinfo, M_DHT);
206 for (i = 1; i <= 16; i++)
207 length += htbl->bits[i];
209 emit_2bytes(cinfo, length + 2 + 1 + 16);
210 emit_byte(cinfo, index);
212 for (i = 1; i <= 16; i++)
213 emit_byte(cinfo, htbl->bits[i]);
215 for (i = 0; i < length; i++)
216 emit_byte(cinfo, htbl->huffval[i]);
218 htbl->sent_table = TRUE;
224 emit_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. */
229 #ifdef C_ARITH_CODING_SUPPORTED
230 char dc_in_use[NUM_ARITH_TBLS];
231 char ac_in_use[NUM_ARITH_TBLS];
233 jpeg_component_info *compptr;
235 for (i = 0; i < NUM_ARITH_TBLS; i++)
236 dc_in_use[i] = ac_in_use[i] = 0;
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 */
245 ac_in_use[compptr->ac_tbl_no] = 1;
249 for (i = 0; i < NUM_ARITH_TBLS; i++)
250 length += dc_in_use[i] + ac_in_use[i];
252 emit_marker(cinfo, M_DAC);
254 emit_2bytes(cinfo, length*2 + 2);
256 for (i = 0; i < NUM_ARITH_TBLS; i++) {
259 emit_byte(cinfo, cinfo->arith_dc_L[i] + (cinfo->arith_dc_U[i]<<4));
262 emit_byte(cinfo, i + 0x10);
263 emit_byte(cinfo, cinfo->arith_ac_K[i]);
266 #endif /* C_ARITH_CODING_SUPPORTED */
271 emit_dri (j_compress_ptr cinfo)
272 /* Emit a DRI marker */
274 emit_marker(cinfo, M_DRI);
276 emit_2bytes(cinfo, 4); /* fixed length */
278 emit_2bytes(cinfo, (int) cinfo->restart_interval);
283 emit_sof (j_compress_ptr cinfo, JPEG_MARKER code)
284 /* Emit a SOF marker */
287 jpeg_component_info *compptr;
289 emit_marker(cinfo, code);
291 emit_2bytes(cinfo, 3 * cinfo->num_components + 2 + 5 + 1); /* length */
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);
298 emit_byte(cinfo, cinfo->data_precision);
299 emit_2bytes(cinfo, (int) cinfo->jpeg_height);
300 emit_2bytes(cinfo, (int) cinfo->jpeg_width);
302 emit_byte(cinfo, cinfo->num_components);
304 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
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);
314 emit_sos (j_compress_ptr cinfo)
315 /* Emit a SOS marker */
318 jpeg_component_info *compptr;
320 emit_marker(cinfo, M_SOS);
322 emit_2bytes(cinfo, 2 * cinfo->comps_in_scan + 2 + 1 + 3); /* length */
324 emit_byte(cinfo, cinfo->comps_in_scan);
326 for (i = 0; i < cinfo->comps_in_scan; i++) {
327 compptr = cinfo->cur_comp_info[i];
328 emit_byte(cinfo, compptr->component_id);
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.
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;
339 emit_byte(cinfo, (td << 4) + ta);
342 emit_byte(cinfo, cinfo->Ss);
343 emit_byte(cinfo, cinfo->Se);
344 emit_byte(cinfo, (cinfo->Ah << 4) + cinfo->Al);
349 emit_pseudo_sos (j_compress_ptr cinfo)
350 /* Emit a pseudo SOS marker */
352 emit_marker(cinfo, M_SOS);
354 emit_2bytes(cinfo, 2 + 1 + 3); /* length */
356 emit_byte(cinfo, 0); /* Ns */
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 */
365 emit_jfif_app0 (j_compress_ptr cinfo)
366 /* Emit a JFIF-compliant APP0 marker */
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)
380 emit_marker(cinfo, M_APP0);
382 emit_2bytes(cinfo, 2 + 4 + 1 + 2 + 1 + 2 + 2 + 1 + 1); /* length */
384 emit_byte(cinfo, 0x4A); /* Identifier: ASCII "JFIF" */
385 emit_byte(cinfo, 0x46);
386 emit_byte(cinfo, 0x49);
387 emit_byte(cinfo, 0x46);
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 */
400 emit_adobe_app14 (j_compress_ptr cinfo)
401 /* Emit an Adobe APP14 marker */
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)
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.
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.
419 emit_marker(cinfo, M_APP14);
421 emit_2bytes(cinfo, 2 + 5 + 2 + 2 + 2 + 1); /* length */
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) {
433 emit_byte(cinfo, 1); /* Color transform = 1 */
436 emit_byte(cinfo, 2); /* Color transform = 2 */
439 emit_byte(cinfo, 0); /* Color transform = 0 */
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.
454 write_marker_header (j_compress_ptr cinfo, int marker, unsigned int datalen)
455 /* Emit an arbitrary marker header */
457 if (datalen > (unsigned int) 65533) /* safety check */
458 ERREXIT(cinfo, JERR_BAD_LENGTH);
460 emit_marker(cinfo, (JPEG_MARKER) marker);
462 emit_2bytes(cinfo, (int) (datalen + 2)); /* total length */
466 write_marker_byte (j_compress_ptr cinfo, int val)
467 /* Emit one byte of marker parameters following write_marker_header */
469 emit_byte(cinfo, val);
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.
485 write_file_header (j_compress_ptr cinfo)
487 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
489 emit_marker(cinfo, M_SOI); /* first the SOI */
491 /* SOI is defined to reset restart interval to 0 */
492 marker->last_restart_interval = 0;
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);
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.
510 write_frame_header (j_compress_ptr cinfo)
514 jpeg_component_info *compptr;
516 /* Emit DQT for each quantization table.
517 * Note that emit_dqt() suppresses any duplicate tables.
520 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
522 prec += emit_dqt(cinfo, compptr->quant_tbl_no);
524 /* now prec is nonzero iff there are any 16-bit quant tables. */
526 /* Check for a non-baseline specification.
527 * Note we assume that Huffman table numbers won't be changed later.
529 if (cinfo->arith_code || cinfo->progressive_mode ||
530 cinfo->data_precision != 8 || cinfo->block_size != DCTSIZE) {
534 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
536 if (compptr->dc_tbl_no > 1 || compptr->ac_tbl_no > 1)
539 if (prec && is_baseline) {
541 /* If it's baseline except for quantizer size, warn the user */
542 TRACEMS(cinfo, 0, JTRC_16BIT_TABLES);
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 */
551 emit_sof(cinfo, M_SOF9); /* SOF code for sequential arithmetic */
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 */
558 emit_sof(cinfo, M_SOF1); /* SOF code for non-baseline Huffman file */
561 /* Check to emit pseudo SOS marker */
562 if (cinfo->progressive_mode && cinfo->block_size != DCTSIZE)
563 emit_pseudo_sos(cinfo);
569 * This consists of DHT or DAC markers, optional DRI, and SOS.
570 * Compressed data will be written following the SOS.
574 write_scan_header (j_compress_ptr cinfo)
576 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
578 jpeg_component_info *compptr;
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.
587 /* Emit Huffman tables.
588 * Note that emit_dht() suppresses any duplicate tables.
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 */
597 emit_dht(cinfo, compptr->ac_tbl_no, TRUE);
601 /* Emit DRI if required --- note that DRI value could change for each scan.
602 * We avoid wasting space with unnecessary DRIs, however.
604 if (cinfo->restart_interval != marker->last_restart_interval) {
606 marker->last_restart_interval = cinfo->restart_interval;
614 * Write datastream trailer.
618 write_file_trailer (j_compress_ptr cinfo)
620 emit_marker(cinfo, M_EOI);
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.
632 write_tables_only (j_compress_ptr cinfo)
636 emit_marker(cinfo, M_SOI);
638 for (i = 0; i < NUM_QUANT_TBLS; i++) {
639 if (cinfo->quant_tbl_ptrs[i] != NULL)
640 (void) emit_dqt(cinfo, i);
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);
652 emit_marker(cinfo, M_EOI);
657 * Initialize the marker writer module.
661 jinit_marker_writer (j_compress_ptr cinfo)
663 my_marker_ptr marker;
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;