4 * This file was part of the Independent JPEG Group's software:
5 * Copyright (C) 1991-1998, Thomas G. Lane.
6 * Modified 2003-2010 by Guido Vollbeding.
7 * libjpeg-turbo Modifications:
8 * Copyright (C) 2010, D. R. Commander.
9 * For conditions of distribution and use, see the accompanying README.ijg
12 * This file contains routines to write JPEG datastream markers.
15 #define JPEG_INTERNALS
21 typedef enum { /* JPEG marker codes */
92 struct jpeg_marker_writer pub
; /* public fields */
94 unsigned int last_restart_interval
; /* last DRI value emitted; 0 after SOI */
97 typedef my_marker_writer
*my_marker_ptr
;
101 * Basic output routines.
103 * Note that we do not support suspension while writing a marker.
104 * Therefore, an application using suspension must ensure that there is
105 * enough buffer space for the initial markers (typ. 600-700 bytes) before
106 * calling jpeg_start_compress, and enough space to write the trailing EOI
107 * (a few bytes) before calling jpeg_finish_compress. Multipass compression
108 * modes are not supported at all with suspension, so those two are the only
109 * points where markers will be written.
113 emit_byte(j_compress_ptr cinfo
, int val
)
116 struct jpeg_destination_mgr
*dest
= cinfo
->dest
;
118 *(dest
->next_output_byte
)++ = (JOCTET
)val
;
119 if (--dest
->free_in_buffer
== 0) {
120 if (!(*dest
->empty_output_buffer
) (cinfo
))
121 ERREXIT(cinfo
, JERR_CANT_SUSPEND
);
127 emit_marker(j_compress_ptr cinfo
, JPEG_MARKER mark
)
128 /* Emit a marker code */
130 emit_byte(cinfo
, 0xFF);
131 emit_byte(cinfo
, (int)mark
);
136 emit_2bytes(j_compress_ptr cinfo
, int value
)
137 /* Emit a 2-byte integer; these are always MSB first in JPEG files */
139 emit_byte(cinfo
, (value
>> 8) & 0xFF);
140 emit_byte(cinfo
, value
& 0xFF);
145 * Routines to write specific marker types.
149 emit_dqt(j_compress_ptr cinfo
, int index
)
150 /* Emit a DQT marker */
151 /* Returns the precision used (0 = 8bits, 1 = 16bits) for baseline checking */
153 JQUANT_TBL
*qtbl
= cinfo
->quant_tbl_ptrs
[index
];
158 ERREXIT1(cinfo
, JERR_NO_QUANT_TABLE
, index
);
161 for (i
= 0; i
< DCTSIZE2
; i
++) {
162 if (qtbl
->quantval
[i
] > 255)
166 if (!qtbl
->sent_table
) {
167 emit_marker(cinfo
, M_DQT
);
169 emit_2bytes(cinfo
, prec
? DCTSIZE2
* 2 + 1 + 2 : DCTSIZE2
+ 1 + 2);
171 emit_byte(cinfo
, index
+ (prec
<< 4));
173 for (i
= 0; i
< DCTSIZE2
; i
++) {
174 /* The table entries must be emitted in zigzag order. */
175 unsigned int qval
= qtbl
->quantval
[jpeg_natural_order
[i
]];
177 emit_byte(cinfo
, (int)(qval
>> 8));
178 emit_byte(cinfo
, (int)(qval
& 0xFF));
181 qtbl
->sent_table
= TRUE
;
189 emit_dht(j_compress_ptr cinfo
, int index
, boolean is_ac
)
190 /* Emit a DHT marker */
196 htbl
= cinfo
->ac_huff_tbl_ptrs
[index
];
197 index
+= 0x10; /* output index has AC bit set */
199 htbl
= cinfo
->dc_huff_tbl_ptrs
[index
];
203 ERREXIT1(cinfo
, JERR_NO_HUFF_TABLE
, index
);
205 if (!htbl
->sent_table
) {
206 emit_marker(cinfo
, M_DHT
);
209 for (i
= 1; i
<= 16; i
++)
210 length
+= htbl
->bits
[i
];
212 emit_2bytes(cinfo
, length
+ 2 + 1 + 16);
213 emit_byte(cinfo
, index
);
215 for (i
= 1; i
<= 16; i
++)
216 emit_byte(cinfo
, htbl
->bits
[i
]);
218 for (i
= 0; i
< length
; i
++)
219 emit_byte(cinfo
, htbl
->huffval
[i
]);
221 htbl
->sent_table
= TRUE
;
227 emit_dac(j_compress_ptr cinfo
)
228 /* Emit a DAC marker */
229 /* Since the useful info is so small, we want to emit all the tables in */
230 /* one DAC marker. Therefore this routine does its own scan of the table. */
232 #ifdef C_ARITH_CODING_SUPPORTED
233 char dc_in_use
[NUM_ARITH_TBLS
];
234 char ac_in_use
[NUM_ARITH_TBLS
];
236 jpeg_component_info
*compptr
;
238 for (i
= 0; i
< NUM_ARITH_TBLS
; i
++)
239 dc_in_use
[i
] = ac_in_use
[i
] = 0;
241 for (i
= 0; i
< cinfo
->comps_in_scan
; i
++) {
242 compptr
= cinfo
->cur_comp_info
[i
];
243 /* DC needs no table for refinement scan */
244 if (cinfo
->Ss
== 0 && cinfo
->Ah
== 0)
245 dc_in_use
[compptr
->dc_tbl_no
] = 1;
246 /* AC needs no table when not present */
248 ac_in_use
[compptr
->ac_tbl_no
] = 1;
252 for (i
= 0; i
< NUM_ARITH_TBLS
; i
++)
253 length
+= dc_in_use
[i
] + ac_in_use
[i
];
256 emit_marker(cinfo
, M_DAC
);
258 emit_2bytes(cinfo
, length
* 2 + 2);
260 for (i
= 0; i
< NUM_ARITH_TBLS
; i
++) {
263 emit_byte(cinfo
, cinfo
->arith_dc_L
[i
] + (cinfo
->arith_dc_U
[i
] << 4));
266 emit_byte(cinfo
, i
+ 0x10);
267 emit_byte(cinfo
, cinfo
->arith_ac_K
[i
]);
271 #endif /* C_ARITH_CODING_SUPPORTED */
276 emit_dri(j_compress_ptr cinfo
)
277 /* Emit a DRI marker */
279 emit_marker(cinfo
, M_DRI
);
281 emit_2bytes(cinfo
, 4); /* fixed length */
283 emit_2bytes(cinfo
, (int)cinfo
->restart_interval
);
288 emit_sof(j_compress_ptr cinfo
, JPEG_MARKER code
)
289 /* Emit a SOF marker */
292 jpeg_component_info
*compptr
;
294 emit_marker(cinfo
, code
);
296 emit_2bytes(cinfo
, 3 * cinfo
->num_components
+ 2 + 5 + 1); /* length */
298 /* Make sure image isn't bigger than SOF field can handle */
299 if ((long)cinfo
->_jpeg_height
> 65535L || (long)cinfo
->_jpeg_width
> 65535L)
300 ERREXIT1(cinfo
, JERR_IMAGE_TOO_BIG
, (unsigned int)65535);
302 emit_byte(cinfo
, cinfo
->data_precision
);
303 emit_2bytes(cinfo
, (int)cinfo
->_jpeg_height
);
304 emit_2bytes(cinfo
, (int)cinfo
->_jpeg_width
);
306 emit_byte(cinfo
, cinfo
->num_components
);
308 for (ci
= 0, compptr
= cinfo
->comp_info
; ci
< cinfo
->num_components
;
310 emit_byte(cinfo
, compptr
->component_id
);
311 emit_byte(cinfo
, (compptr
->h_samp_factor
<< 4) + compptr
->v_samp_factor
);
312 emit_byte(cinfo
, compptr
->quant_tbl_no
);
318 emit_sos(j_compress_ptr cinfo
)
319 /* Emit a SOS marker */
322 jpeg_component_info
*compptr
;
324 emit_marker(cinfo
, M_SOS
);
326 emit_2bytes(cinfo
, 2 * cinfo
->comps_in_scan
+ 2 + 1 + 3); /* length */
328 emit_byte(cinfo
, cinfo
->comps_in_scan
);
330 for (i
= 0; i
< cinfo
->comps_in_scan
; i
++) {
331 compptr
= cinfo
->cur_comp_info
[i
];
332 emit_byte(cinfo
, compptr
->component_id
);
334 /* We emit 0 for unused field(s); this is recommended by the P&M text
335 * but does not seem to be specified in the standard.
338 /* DC needs no table for refinement scan */
339 td
= cinfo
->Ss
== 0 && cinfo
->Ah
== 0 ? compptr
->dc_tbl_no
: 0;
340 /* AC needs no table when not present */
341 ta
= cinfo
->Se
? compptr
->ac_tbl_no
: 0;
343 emit_byte(cinfo
, (td
<< 4) + ta
);
346 emit_byte(cinfo
, cinfo
->Ss
);
347 emit_byte(cinfo
, cinfo
->Se
);
348 emit_byte(cinfo
, (cinfo
->Ah
<< 4) + cinfo
->Al
);
353 emit_jfif_app0(j_compress_ptr cinfo
)
354 /* Emit a JFIF-compliant APP0 marker */
357 * Length of APP0 block (2 bytes)
358 * Block ID (4 bytes - ASCII "JFIF")
359 * Zero byte (1 byte to terminate the ID string)
360 * Version Major, Minor (2 bytes - major first)
361 * Units (1 byte - 0x00 = none, 0x01 = inch, 0x02 = cm)
362 * Xdpu (2 bytes - dots per unit horizontal)
363 * Ydpu (2 bytes - dots per unit vertical)
364 * Thumbnail X size (1 byte)
365 * Thumbnail Y size (1 byte)
368 emit_marker(cinfo
, M_APP0
);
370 emit_2bytes(cinfo
, 2 + 4 + 1 + 2 + 1 + 2 + 2 + 1 + 1); /* length */
372 emit_byte(cinfo
, 0x4A); /* Identifier: ASCII "JFIF" */
373 emit_byte(cinfo
, 0x46);
374 emit_byte(cinfo
, 0x49);
375 emit_byte(cinfo
, 0x46);
377 emit_byte(cinfo
, cinfo
->JFIF_major_version
); /* Version fields */
378 emit_byte(cinfo
, cinfo
->JFIF_minor_version
);
379 emit_byte(cinfo
, cinfo
->density_unit
); /* Pixel size information */
380 emit_2bytes(cinfo
, (int)cinfo
->X_density
);
381 emit_2bytes(cinfo
, (int)cinfo
->Y_density
);
382 emit_byte(cinfo
, 0); /* No thumbnail image */
388 emit_adobe_app14(j_compress_ptr cinfo
)
389 /* Emit an Adobe APP14 marker */
392 * Length of APP14 block (2 bytes)
393 * Block ID (5 bytes - ASCII "Adobe")
394 * Version Number (2 bytes - currently 100)
395 * Flags0 (2 bytes - currently 0)
396 * Flags1 (2 bytes - currently 0)
397 * Color transform (1 byte)
399 * Although Adobe TN 5116 mentions Version = 101, all the Adobe files
400 * now in circulation seem to use Version = 100, so that's what we write.
402 * We write the color transform byte as 1 if the JPEG color space is
403 * YCbCr, 2 if it's YCCK, 0 otherwise. Adobe's definition has to do with
404 * whether the encoder performed a transformation, which is pretty useless.
407 emit_marker(cinfo
, M_APP14
);
409 emit_2bytes(cinfo
, 2 + 5 + 2 + 2 + 2 + 1); /* length */
411 emit_byte(cinfo
, 0x41); /* Identifier: ASCII "Adobe" */
412 emit_byte(cinfo
, 0x64);
413 emit_byte(cinfo
, 0x6F);
414 emit_byte(cinfo
, 0x62);
415 emit_byte(cinfo
, 0x65);
416 emit_2bytes(cinfo
, 100); /* Version */
417 emit_2bytes(cinfo
, 0); /* Flags0 */
418 emit_2bytes(cinfo
, 0); /* Flags1 */
419 switch (cinfo
->jpeg_color_space
) {
421 emit_byte(cinfo
, 1); /* Color transform = 1 */
424 emit_byte(cinfo
, 2); /* Color transform = 2 */
427 emit_byte(cinfo
, 0); /* Color transform = 0 */
434 * These routines allow writing an arbitrary marker with parameters.
435 * The only intended use is to emit COM or APPn markers after calling
436 * write_file_header and before calling write_frame_header.
437 * Other uses are not guaranteed to produce desirable results.
438 * Counting the parameter bytes properly is the caller's responsibility.
442 write_marker_header(j_compress_ptr cinfo
, int marker
, unsigned int datalen
)
443 /* Emit an arbitrary marker header */
445 if (datalen
> (unsigned int)65533) /* safety check */
446 ERREXIT(cinfo
, JERR_BAD_LENGTH
);
448 emit_marker(cinfo
, (JPEG_MARKER
)marker
);
450 emit_2bytes(cinfo
, (int)(datalen
+ 2)); /* total length */
454 write_marker_byte(j_compress_ptr cinfo
, int val
)
455 /* Emit one byte of marker parameters following write_marker_header */
457 emit_byte(cinfo
, val
);
462 * Write datastream header.
463 * This consists of an SOI and optional APPn markers.
464 * We recommend use of the JFIF marker, but not the Adobe marker,
465 * when using YCbCr or grayscale data. The JFIF marker should NOT
466 * be used for any other JPEG colorspace. The Adobe marker is helpful
467 * to distinguish RGB, CMYK, and YCCK colorspaces.
468 * Note that an application can write additional header markers after
469 * jpeg_start_compress returns.
473 write_file_header(j_compress_ptr cinfo
)
475 my_marker_ptr marker
= (my_marker_ptr
)cinfo
->marker
;
477 emit_marker(cinfo
, M_SOI
); /* first the SOI */
479 /* SOI is defined to reset restart interval to 0 */
480 marker
->last_restart_interval
= 0;
482 if (cinfo
->write_JFIF_header
) /* next an optional JFIF APP0 */
483 emit_jfif_app0(cinfo
);
484 if (cinfo
->write_Adobe_marker
) /* next an optional Adobe APP14 */
485 emit_adobe_app14(cinfo
);
490 * Write frame header.
491 * This consists of DQT and SOFn markers.
492 * Note that we do not emit the SOF until we have emitted the DQT(s).
493 * This avoids compatibility problems with incorrect implementations that
494 * try to error-check the quant table numbers as soon as they see the SOF.
498 write_frame_header(j_compress_ptr cinfo
)
502 jpeg_component_info
*compptr
;
504 /* Emit DQT for each quantization table.
505 * Note that emit_dqt() suppresses any duplicate tables.
508 for (ci
= 0, compptr
= cinfo
->comp_info
; ci
< cinfo
->num_components
;
510 prec
+= emit_dqt(cinfo
, compptr
->quant_tbl_no
);
512 /* now prec is nonzero iff there are any 16-bit quant tables. */
514 /* Check for a non-baseline specification.
515 * Note we assume that Huffman table numbers won't be changed later.
517 if (cinfo
->arith_code
|| cinfo
->progressive_mode
||
518 cinfo
->data_precision
!= 8) {
522 for (ci
= 0, compptr
= cinfo
->comp_info
; ci
< cinfo
->num_components
;
524 if (compptr
->dc_tbl_no
> 1 || compptr
->ac_tbl_no
> 1)
527 if (prec
&& is_baseline
) {
529 /* If it's baseline except for quantizer size, warn the user */
530 TRACEMS(cinfo
, 0, JTRC_16BIT_TABLES
);
534 /* Emit the proper SOF marker */
535 if (cinfo
->arith_code
) {
536 if (cinfo
->progressive_mode
)
537 emit_sof(cinfo
, M_SOF10
); /* SOF code for progressive arithmetic */
539 emit_sof(cinfo
, M_SOF9
); /* SOF code for sequential arithmetic */
541 if (cinfo
->progressive_mode
)
542 emit_sof(cinfo
, M_SOF2
); /* SOF code for progressive Huffman */
543 else if (is_baseline
)
544 emit_sof(cinfo
, M_SOF0
); /* SOF code for baseline implementation */
546 emit_sof(cinfo
, M_SOF1
); /* SOF code for non-baseline Huffman file */
553 * This consists of DHT or DAC markers, optional DRI, and SOS.
554 * Compressed data will be written following the SOS.
558 write_scan_header(j_compress_ptr cinfo
)
560 my_marker_ptr marker
= (my_marker_ptr
)cinfo
->marker
;
562 jpeg_component_info
*compptr
;
564 if (cinfo
->arith_code
) {
565 /* Emit arith conditioning info. We may have some duplication
566 * if the file has multiple scans, but it's so small it's hardly
567 * worth worrying about.
571 /* Emit Huffman tables.
572 * Note that emit_dht() suppresses any duplicate tables.
574 for (i
= 0; i
< cinfo
->comps_in_scan
; i
++) {
575 compptr
= cinfo
->cur_comp_info
[i
];
576 /* DC needs no table for refinement scan */
577 if (cinfo
->Ss
== 0 && cinfo
->Ah
== 0)
578 emit_dht(cinfo
, compptr
->dc_tbl_no
, FALSE
);
579 /* AC needs no table when not present */
581 emit_dht(cinfo
, compptr
->ac_tbl_no
, TRUE
);
585 /* Emit DRI if required --- note that DRI value could change for each scan.
586 * We avoid wasting space with unnecessary DRIs, however.
588 if (cinfo
->restart_interval
!= marker
->last_restart_interval
) {
590 marker
->last_restart_interval
= cinfo
->restart_interval
;
598 * Write datastream trailer.
602 write_file_trailer(j_compress_ptr cinfo
)
604 emit_marker(cinfo
, M_EOI
);
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.
616 write_tables_only(j_compress_ptr cinfo
)
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
);
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
);
636 emit_marker(cinfo
, M_EOI
);
641 * Initialize the marker writer module.
645 jinit_marker_writer(j_compress_ptr cinfo
)
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;