4
* Copyright (C) 1991-1998, Thomas G. Lane.
5
* Modified 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 decode JPEG datastream markers.
10
* Most of the complexity arises from our desire to support input
11
* suspension: if not all of the data for a marker is available,
12
* we must exit back to the application. On resumption, we reprocess
16
#define JPEG_INTERNALS
21
typedef enum { /* JPEG marker codes */
92
struct jpeg_marker_reader pub; /* public fields */
94
/* Application-overridable marker processing methods */
95
jpeg_marker_parser_method process_COM;
96
jpeg_marker_parser_method process_APPn[16];
98
/* Limit on marker data length to save for each marker type */
99
unsigned int length_limit_COM;
100
unsigned int length_limit_APPn[16];
102
/* Status of COM/APPn marker saving */
103
jpeg_saved_marker_ptr cur_marker; /* NULL if not processing a marker */
104
unsigned int bytes_read; /* data bytes read so far in marker */
105
/* Note: cur_marker is not linked into marker_list until it's all read. */
108
typedef my_marker_reader * my_marker_ptr;
112
* Macros for fetching data from the data source module.
114
* At all times, cinfo->src->next_input_byte and ->bytes_in_buffer reflect
115
* the current restart point; we update them only when we have reached a
116
* suitable place to restart if a suspension occurs.
119
/* Declare and initialize local copies of input pointer/count */
120
#define INPUT_VARS(cinfo) \
121
struct jpeg_source_mgr * datasrc = (cinfo)->src; \
122
const JOCTET * next_input_byte = datasrc->next_input_byte; \
123
size_t bytes_in_buffer = datasrc->bytes_in_buffer
125
/* Unload the local copies --- do this only at a restart boundary */
126
#define INPUT_SYNC(cinfo) \
127
( datasrc->next_input_byte = next_input_byte, \
128
datasrc->bytes_in_buffer = bytes_in_buffer )
130
/* Reload the local copies --- used only in MAKE_BYTE_AVAIL */
131
#define INPUT_RELOAD(cinfo) \
132
( next_input_byte = datasrc->next_input_byte, \
133
bytes_in_buffer = datasrc->bytes_in_buffer )
135
/* Internal macro for INPUT_BYTE and INPUT_2BYTES: make a byte available.
136
* Note we do *not* do INPUT_SYNC before calling fill_input_buffer,
137
* but we must reload the local copies after a successful fill.
139
#define MAKE_BYTE_AVAIL(cinfo,action) \
140
if (bytes_in_buffer == 0) { \
141
if (! (*datasrc->fill_input_buffer) (cinfo)) \
143
INPUT_RELOAD(cinfo); \
146
/* Read a byte into variable V.
147
* If must suspend, take the specified action (typically "return FALSE").
149
#define INPUT_BYTE(cinfo,V,action) \
150
MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \
152
V = GETJOCTET(*next_input_byte++); )
154
/* As above, but read two bytes interpreted as an unsigned 16-bit integer.
155
* V should be declared unsigned int or perhaps INT32.
157
#define INPUT_2BYTES(cinfo,V,action) \
158
MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \
160
V = ((unsigned int) GETJOCTET(*next_input_byte++)) << 8; \
161
MAKE_BYTE_AVAIL(cinfo,action); \
163
V += GETJOCTET(*next_input_byte++); )
167
* Routines to process JPEG markers.
169
* Entry condition: JPEG marker itself has been read and its code saved
170
* in cinfo->unread_marker; input restart point is just after the marker.
172
* Exit: if return TRUE, have read and processed any parameters, and have
173
* updated the restart point to point after the parameters.
174
* If return FALSE, was forced to suspend before reaching end of
175
* marker parameters; restart point has not been moved. Same routine
176
* will be called again after application supplies more input data.
178
* This approach to suspension assumes that all of a marker's parameters
179
* can fit into a single input bufferload. This should hold for "normal"
180
* markers. Some COM/APPn markers might have large parameter segments
181
* that might not fit. If we are simply dropping such a marker, we use
182
* skip_input_data to get past it, and thereby put the problem on the
183
* source manager's shoulders. If we are saving the marker's contents
184
* into memory, we use a slightly different convention: when forced to
185
* suspend, the marker processor updates the restart point to the end of
186
* what it's consumed (ie, the end of the buffer) before returning FALSE.
187
* On resumption, cinfo->unread_marker still contains the marker code,
188
* but the data source will point to the next chunk of marker data.
189
* The marker processor must retain internal state to deal with this.
191
* Note that we don't bother to avoid duplicate trace messages if a
192
* suspension occurs within marker parameters. Other side effects
198
get_soi (j_decompress_ptr cinfo)
199
/* Process an SOI marker */
203
TRACEMS(cinfo, 1, JTRC_SOI);
205
if (cinfo->marker->saw_SOI)
206
ERREXIT(cinfo, JERR_SOI_DUPLICATE);
208
/* Reset all parameters that are defined to be reset by SOI */
210
for (i = 0; i < NUM_ARITH_TBLS; i++) {
211
cinfo->arith_dc_L[i] = 0;
212
cinfo->arith_dc_U[i] = 1;
213
cinfo->arith_ac_K[i] = 5;
215
cinfo->restart_interval = 0;
217
/* Set initial assumptions for colorspace etc */
219
cinfo->jpeg_color_space = JCS_UNKNOWN;
220
cinfo->CCIR601_sampling = FALSE; /* Assume non-CCIR sampling??? */
222
cinfo->saw_JFIF_marker = FALSE;
223
cinfo->JFIF_major_version = 1; /* set default JFIF APP0 values */
224
cinfo->JFIF_minor_version = 1;
225
cinfo->density_unit = 0;
226
cinfo->X_density = 1;
227
cinfo->Y_density = 1;
228
cinfo->saw_Adobe_marker = FALSE;
229
cinfo->Adobe_transform = 0;
231
cinfo->marker->saw_SOI = TRUE;
238
get_sof (j_decompress_ptr cinfo, boolean is_baseline, boolean is_prog,
240
/* Process a SOFn marker */
244
jpeg_component_info * compptr;
247
cinfo->is_baseline = is_baseline;
248
cinfo->progressive_mode = is_prog;
249
cinfo->arith_code = is_arith;
251
INPUT_2BYTES(cinfo, length, return FALSE);
253
INPUT_BYTE(cinfo, cinfo->data_precision, return FALSE);
254
INPUT_2BYTES(cinfo, cinfo->image_height, return FALSE);
255
INPUT_2BYTES(cinfo, cinfo->image_width, return FALSE);
256
INPUT_BYTE(cinfo, cinfo->num_components, return FALSE);
260
TRACEMS4(cinfo, 1, JTRC_SOF, cinfo->unread_marker,
261
(int) cinfo->image_width, (int) cinfo->image_height,
262
cinfo->num_components);
264
if (cinfo->marker->saw_SOF)
265
ERREXIT(cinfo, JERR_SOF_DUPLICATE);
267
/* We don't support files in which the image height is initially specified */
268
/* as 0 and is later redefined by DNL. As long as we have to check that, */
269
/* might as well have a general sanity check. */
270
if (cinfo->image_height <= 0 || cinfo->image_width <= 0
271
|| cinfo->num_components <= 0)
272
ERREXIT(cinfo, JERR_EMPTY_IMAGE);
274
if (length != (cinfo->num_components * 3))
275
ERREXIT(cinfo, JERR_BAD_LENGTH);
277
if (cinfo->comp_info == NULL) /* do only once, even if suspend */
278
cinfo->comp_info = (jpeg_component_info *) (*cinfo->mem->alloc_small)
279
((j_common_ptr) cinfo, JPOOL_IMAGE,
280
cinfo->num_components * SIZEOF(jpeg_component_info));
282
for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
284
compptr->component_index = ci;
285
INPUT_BYTE(cinfo, compptr->component_id, return FALSE);
286
INPUT_BYTE(cinfo, c, return FALSE);
287
compptr->h_samp_factor = (c >> 4) & 15;
288
compptr->v_samp_factor = (c ) & 15;
289
INPUT_BYTE(cinfo, compptr->quant_tbl_no, return FALSE);
291
TRACEMS4(cinfo, 1, JTRC_SOF_COMPONENT,
292
compptr->component_id, compptr->h_samp_factor,
293
compptr->v_samp_factor, compptr->quant_tbl_no);
296
cinfo->marker->saw_SOF = TRUE;
304
get_sos (j_decompress_ptr cinfo)
305
/* Process a SOS marker */
309
jpeg_component_info * compptr;
312
if (! cinfo->marker->saw_SOF)
313
ERREXIT(cinfo, JERR_SOS_NO_SOF);
315
INPUT_2BYTES(cinfo, length, return FALSE);
317
INPUT_BYTE(cinfo, n, return FALSE); /* Number of components */
319
TRACEMS1(cinfo, 1, JTRC_SOS, n);
321
if (length != (n * 2 + 6) || n > MAX_COMPS_IN_SCAN ||
322
(n == 0 && !cinfo->progressive_mode))
323
/* pseudo SOS marker only allowed in progressive mode */
324
ERREXIT(cinfo, JERR_BAD_LENGTH);
326
cinfo->comps_in_scan = n;
328
/* Collect the component-spec parameters */
330
for (i = 0; i < n; i++) {
331
INPUT_BYTE(cinfo, cc, return FALSE);
332
INPUT_BYTE(cinfo, c, return FALSE);
334
for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
336
if (cc == compptr->component_id)
340
ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc);
344
cinfo->cur_comp_info[i] = compptr;
345
compptr->dc_tbl_no = (c >> 4) & 15;
346
compptr->ac_tbl_no = (c ) & 15;
348
TRACEMS3(cinfo, 1, JTRC_SOS_COMPONENT, cc,
349
compptr->dc_tbl_no, compptr->ac_tbl_no);
352
/* Collect the additional scan parameters Ss, Se, Ah/Al. */
353
INPUT_BYTE(cinfo, c, return FALSE);
355
INPUT_BYTE(cinfo, c, return FALSE);
357
INPUT_BYTE(cinfo, c, return FALSE);
358
cinfo->Ah = (c >> 4) & 15;
359
cinfo->Al = (c ) & 15;
361
TRACEMS4(cinfo, 1, JTRC_SOS_PARAMS, cinfo->Ss, cinfo->Se,
362
cinfo->Ah, cinfo->Al);
364
/* Prepare to scan data & restart markers */
365
cinfo->marker->next_restart_num = 0;
367
/* Count another (non-pseudo) SOS marker */
368
if (n) cinfo->input_scan_number++;
375
#ifdef D_ARITH_CODING_SUPPORTED
378
get_dac (j_decompress_ptr cinfo)
379
/* Process a DAC marker */
385
INPUT_2BYTES(cinfo, length, return FALSE);
389
INPUT_BYTE(cinfo, index, return FALSE);
390
INPUT_BYTE(cinfo, val, return FALSE);
394
TRACEMS2(cinfo, 1, JTRC_DAC, index, val);
396
if (index < 0 || index >= (2*NUM_ARITH_TBLS))
397
ERREXIT1(cinfo, JERR_DAC_INDEX, index);
399
if (index >= NUM_ARITH_TBLS) { /* define AC table */
400
cinfo->arith_ac_K[index-NUM_ARITH_TBLS] = (UINT8) val;
401
} else { /* define DC table */
402
cinfo->arith_dc_L[index] = (UINT8) (val & 0x0F);
403
cinfo->arith_dc_U[index] = (UINT8) (val >> 4);
404
if (cinfo->arith_dc_L[index] > cinfo->arith_dc_U[index])
405
ERREXIT1(cinfo, JERR_DAC_VALUE, val);
410
ERREXIT(cinfo, JERR_BAD_LENGTH);
416
#else /* ! D_ARITH_CODING_SUPPORTED */
418
#define get_dac(cinfo) skip_variable(cinfo)
420
#endif /* D_ARITH_CODING_SUPPORTED */
424
get_dht (j_decompress_ptr cinfo)
425
/* Process a DHT marker */
434
INPUT_2BYTES(cinfo, length, return FALSE);
437
while (length > 16) {
438
INPUT_BYTE(cinfo, index, return FALSE);
440
TRACEMS1(cinfo, 1, JTRC_DHT, index);
444
for (i = 1; i <= 16; i++) {
445
INPUT_BYTE(cinfo, bits[i], return FALSE);
451
TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
452
bits[1], bits[2], bits[3], bits[4],
453
bits[5], bits[6], bits[7], bits[8]);
454
TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
455
bits[9], bits[10], bits[11], bits[12],
456
bits[13], bits[14], bits[15], bits[16]);
458
/* Here we just do minimal validation of the counts to avoid walking
459
* off the end of our table space. jdhuff.c will check more carefully.
461
if (count > 256 || ((INT32) count) > length)
462
ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
464
for (i = 0; i < count; i++)
465
INPUT_BYTE(cinfo, huffval[i], return FALSE);
469
if (index & 0x10) { /* AC table definition */
471
htblptr = &cinfo->ac_huff_tbl_ptrs[index];
472
} else { /* DC table definition */
473
htblptr = &cinfo->dc_huff_tbl_ptrs[index];
476
if (index < 0 || index >= NUM_HUFF_TBLS)
477
ERREXIT1(cinfo, JERR_DHT_INDEX, index);
479
if (*htblptr == NULL)
480
*htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
482
MEMCOPY((*htblptr)->bits, bits, SIZEOF((*htblptr)->bits));
483
MEMCOPY((*htblptr)->huffval, huffval, SIZEOF((*htblptr)->huffval));
487
ERREXIT(cinfo, JERR_BAD_LENGTH);
495
get_dqt (j_decompress_ptr cinfo)
496
/* Process a DQT marker */
498
INT32 length, count, i;
501
JQUANT_TBL *quant_ptr;
502
const int *natural_order;
505
INPUT_2BYTES(cinfo, length, return FALSE);
510
INPUT_BYTE(cinfo, n, return FALSE);
514
TRACEMS2(cinfo, 1, JTRC_DQT, n, prec);
516
if (n >= NUM_QUANT_TBLS)
517
ERREXIT1(cinfo, JERR_DQT_INDEX, n);
519
if (cinfo->quant_tbl_ptrs[n] == NULL)
520
cinfo->quant_tbl_ptrs[n] = jpeg_alloc_quant_table((j_common_ptr) cinfo);
521
quant_ptr = cinfo->quant_tbl_ptrs[n];
524
if (length < DCTSIZE2 * 2) {
525
/* Initialize full table for safety. */
526
for (i = 0; i < DCTSIZE2; i++) {
527
quant_ptr->quantval[i] = 1;
533
if (length < DCTSIZE2) {
534
/* Initialize full table for safety. */
535
for (i = 0; i < DCTSIZE2; i++) {
536
quant_ptr->quantval[i] = 1;
544
case (2*2): natural_order = jpeg_natural_order2; break;
545
case (3*3): natural_order = jpeg_natural_order3; break;
546
case (4*4): natural_order = jpeg_natural_order4; break;
547
case (5*5): natural_order = jpeg_natural_order5; break;
548
case (6*6): natural_order = jpeg_natural_order6; break;
549
case (7*7): natural_order = jpeg_natural_order7; break;
550
default: natural_order = jpeg_natural_order; break;
553
for (i = 0; i < count; i++) {
555
INPUT_2BYTES(cinfo, tmp, return FALSE);
557
INPUT_BYTE(cinfo, tmp, return FALSE);
558
/* We convert the zigzag-order table to natural array order. */
559
quant_ptr->quantval[natural_order[i]] = (UINT16) tmp;
562
if (cinfo->err->trace_level >= 2) {
563
for (i = 0; i < DCTSIZE2; i += 8) {
564
TRACEMS8(cinfo, 2, JTRC_QUANTVALS,
565
quant_ptr->quantval[i], quant_ptr->quantval[i+1],
566
quant_ptr->quantval[i+2], quant_ptr->quantval[i+3],
567
quant_ptr->quantval[i+4], quant_ptr->quantval[i+5],
568
quant_ptr->quantval[i+6], quant_ptr->quantval[i+7]);
573
if (prec) length -= count;
577
ERREXIT(cinfo, JERR_BAD_LENGTH);
585
get_dri (j_decompress_ptr cinfo)
586
/* Process a DRI marker */
592
INPUT_2BYTES(cinfo, length, return FALSE);
595
ERREXIT(cinfo, JERR_BAD_LENGTH);
597
INPUT_2BYTES(cinfo, tmp, return FALSE);
599
TRACEMS1(cinfo, 1, JTRC_DRI, tmp);
601
cinfo->restart_interval = tmp;
609
* Routines for processing APPn and COM markers.
610
* These are either saved in memory or discarded, per application request.
611
* APP0 and APP14 are specially checked to see if they are
612
* JFIF and Adobe markers, respectively.
615
#define APP0_DATA_LEN 14 /* Length of interesting data in APP0 */
616
#define APP14_DATA_LEN 12 /* Length of interesting data in APP14 */
617
#define APPN_DATA_LEN 14 /* Must be the largest of the above!! */
621
examine_app0 (j_decompress_ptr cinfo, JOCTET FAR * data,
622
unsigned int datalen, INT32 remaining)
623
/* Examine first few bytes from an APP0.
624
* Take appropriate action if it is a JFIF marker.
625
* datalen is # of bytes at data[], remaining is length of rest of marker data.
628
INT32 totallen = (INT32) datalen + remaining;
630
if (datalen >= APP0_DATA_LEN &&
631
GETJOCTET(data[0]) == 0x4A &&
632
GETJOCTET(data[1]) == 0x46 &&
633
GETJOCTET(data[2]) == 0x49 &&
634
GETJOCTET(data[3]) == 0x46 &&
635
GETJOCTET(data[4]) == 0) {
636
/* Found JFIF APP0 marker: save info */
637
cinfo->saw_JFIF_marker = TRUE;
638
cinfo->JFIF_major_version = GETJOCTET(data[5]);
639
cinfo->JFIF_minor_version = GETJOCTET(data[6]);
640
cinfo->density_unit = GETJOCTET(data[7]);
641
cinfo->X_density = (GETJOCTET(data[8]) << 8) + GETJOCTET(data[9]);
642
cinfo->Y_density = (GETJOCTET(data[10]) << 8) + GETJOCTET(data[11]);
644
* Major version must be 1, anything else signals an incompatible change.
645
* (We used to treat this as an error, but now it's a nonfatal warning,
646
* because some bozo at Hijaak couldn't read the spec.)
647
* Minor version should be 0..2, but process anyway if newer.
649
if (cinfo->JFIF_major_version != 1)
650
WARNMS2(cinfo, JWRN_JFIF_MAJOR,
651
cinfo->JFIF_major_version, cinfo->JFIF_minor_version);
652
/* Generate trace messages */
653
TRACEMS5(cinfo, 1, JTRC_JFIF,
654
cinfo->JFIF_major_version, cinfo->JFIF_minor_version,
655
cinfo->X_density, cinfo->Y_density, cinfo->density_unit);
656
/* Validate thumbnail dimensions and issue appropriate messages */
657
if (GETJOCTET(data[12]) | GETJOCTET(data[13]))
658
TRACEMS2(cinfo, 1, JTRC_JFIF_THUMBNAIL,
659
GETJOCTET(data[12]), GETJOCTET(data[13]));
660
totallen -= APP0_DATA_LEN;
662
((INT32)GETJOCTET(data[12]) * (INT32)GETJOCTET(data[13]) * (INT32) 3))
663
TRACEMS1(cinfo, 1, JTRC_JFIF_BADTHUMBNAILSIZE, (int) totallen);
664
} else if (datalen >= 6 &&
665
GETJOCTET(data[0]) == 0x4A &&
666
GETJOCTET(data[1]) == 0x46 &&
667
GETJOCTET(data[2]) == 0x58 &&
668
GETJOCTET(data[3]) == 0x58 &&
669
GETJOCTET(data[4]) == 0) {
670
/* Found JFIF "JFXX" extension APP0 marker */
671
/* The library doesn't actually do anything with these,
672
* but we try to produce a helpful trace message.
674
switch (GETJOCTET(data[5])) {
676
TRACEMS1(cinfo, 1, JTRC_THUMB_JPEG, (int) totallen);
679
TRACEMS1(cinfo, 1, JTRC_THUMB_PALETTE, (int) totallen);
682
TRACEMS1(cinfo, 1, JTRC_THUMB_RGB, (int) totallen);
685
TRACEMS2(cinfo, 1, JTRC_JFIF_EXTENSION,
686
GETJOCTET(data[5]), (int) totallen);
690
/* Start of APP0 does not match "JFIF" or "JFXX", or too short */
691
TRACEMS1(cinfo, 1, JTRC_APP0, (int) totallen);
697
examine_app14 (j_decompress_ptr cinfo, JOCTET FAR * data,
698
unsigned int datalen, INT32 remaining)
699
/* Examine first few bytes from an APP14.
700
* Take appropriate action if it is an Adobe marker.
701
* datalen is # of bytes at data[], remaining is length of rest of marker data.
704
unsigned int version, flags0, flags1, transform;
706
if (datalen >= APP14_DATA_LEN &&
707
GETJOCTET(data[0]) == 0x41 &&
708
GETJOCTET(data[1]) == 0x64 &&
709
GETJOCTET(data[2]) == 0x6F &&
710
GETJOCTET(data[3]) == 0x62 &&
711
GETJOCTET(data[4]) == 0x65) {
712
/* Found Adobe APP14 marker */
713
version = (GETJOCTET(data[5]) << 8) + GETJOCTET(data[6]);
714
flags0 = (GETJOCTET(data[7]) << 8) + GETJOCTET(data[8]);
715
flags1 = (GETJOCTET(data[9]) << 8) + GETJOCTET(data[10]);
716
transform = GETJOCTET(data[11]);
717
TRACEMS4(cinfo, 1, JTRC_ADOBE, version, flags0, flags1, transform);
718
cinfo->saw_Adobe_marker = TRUE;
719
cinfo->Adobe_transform = (UINT8) transform;
721
/* Start of APP14 does not match "Adobe", or too short */
722
TRACEMS1(cinfo, 1, JTRC_APP14, (int) (datalen + remaining));
728
get_interesting_appn (j_decompress_ptr cinfo)
729
/* Process an APP0 or APP14 marker without saving it */
732
JOCTET b[APPN_DATA_LEN];
733
unsigned int i, numtoread;
736
INPUT_2BYTES(cinfo, length, return FALSE);
739
/* get the interesting part of the marker data */
740
if (length >= APPN_DATA_LEN)
741
numtoread = APPN_DATA_LEN;
743
numtoread = (unsigned int) length;
746
for (i = 0; i < numtoread; i++)
747
INPUT_BYTE(cinfo, b[i], return FALSE);
751
switch (cinfo->unread_marker) {
753
examine_app0(cinfo, (JOCTET FAR *) b, numtoread, length);
756
examine_app14(cinfo, (JOCTET FAR *) b, numtoread, length);
759
/* can't get here unless jpeg_save_markers chooses wrong processor */
760
ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
764
/* skip any remaining data -- could be lots */
767
(*cinfo->src->skip_input_data) (cinfo, (long) length);
773
#ifdef SAVE_MARKERS_SUPPORTED
776
save_marker (j_decompress_ptr cinfo)
777
/* Save an APPn or COM marker into the marker list */
779
my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
780
jpeg_saved_marker_ptr cur_marker = marker->cur_marker;
781
unsigned int bytes_read, data_length;
786
if (cur_marker == NULL) {
787
/* begin reading a marker */
788
INPUT_2BYTES(cinfo, length, return FALSE);
790
if (length >= 0) { /* watch out for bogus length word */
791
/* figure out how much we want to save */
793
if (cinfo->unread_marker == (int) M_COM)
794
limit = marker->length_limit_COM;
796
limit = marker->length_limit_APPn[cinfo->unread_marker - (int) M_APP0];
797
if ((unsigned int) length < limit)
798
limit = (unsigned int) length;
799
/* allocate and initialize the marker item */
800
cur_marker = (jpeg_saved_marker_ptr)
801
(*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
802
SIZEOF(struct jpeg_marker_struct) + limit);
803
cur_marker->next = NULL;
804
cur_marker->marker = (UINT8) cinfo->unread_marker;
805
cur_marker->original_length = (unsigned int) length;
806
cur_marker->data_length = limit;
807
/* data area is just beyond the jpeg_marker_struct */
808
data = cur_marker->data = (JOCTET FAR *) (cur_marker + 1);
809
marker->cur_marker = cur_marker;
810
marker->bytes_read = 0;
814
/* deal with bogus length word */
815
bytes_read = data_length = 0;
819
/* resume reading a marker */
820
bytes_read = marker->bytes_read;
821
data_length = cur_marker->data_length;
822
data = cur_marker->data + bytes_read;
825
while (bytes_read < data_length) {
826
INPUT_SYNC(cinfo); /* move the restart point to here */
827
marker->bytes_read = bytes_read;
828
/* If there's not at least one byte in buffer, suspend */
829
MAKE_BYTE_AVAIL(cinfo, return FALSE);
830
/* Copy bytes with reasonable rapidity */
831
while (bytes_read < data_length && bytes_in_buffer > 0) {
832
*data++ = *next_input_byte++;
838
/* Done reading what we want to read */
839
if (cur_marker != NULL) { /* will be NULL if bogus length word */
840
/* Add new marker to end of list */
841
if (cinfo->marker_list == NULL) {
842
cinfo->marker_list = cur_marker;
844
jpeg_saved_marker_ptr prev = cinfo->marker_list;
845
while (prev->next != NULL)
847
prev->next = cur_marker;
849
/* Reset pointer & calc remaining data length */
850
data = cur_marker->data;
851
length = cur_marker->original_length - data_length;
853
/* Reset to initial state for next marker */
854
marker->cur_marker = NULL;
856
/* Process the marker if interesting; else just make a generic trace msg */
857
switch (cinfo->unread_marker) {
859
examine_app0(cinfo, data, data_length, length);
862
examine_app14(cinfo, data, data_length, length);
865
TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker,
866
(int) (data_length + length));
870
/* skip any remaining data -- could be lots */
871
INPUT_SYNC(cinfo); /* do before skip_input_data */
873
(*cinfo->src->skip_input_data) (cinfo, (long) length);
878
#endif /* SAVE_MARKERS_SUPPORTED */
882
skip_variable (j_decompress_ptr cinfo)
883
/* Skip over an unknown or uninteresting variable-length marker */
888
INPUT_2BYTES(cinfo, length, return FALSE);
891
TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, (int) length);
893
INPUT_SYNC(cinfo); /* do before skip_input_data */
895
(*cinfo->src->skip_input_data) (cinfo, (long) length);
902
* Find the next JPEG marker, save it in cinfo->unread_marker.
903
* Returns FALSE if had to suspend before reaching a marker;
904
* in that case cinfo->unread_marker is unchanged.
906
* Note that the result might not be a valid marker code,
907
* but it will never be 0 or FF.
911
next_marker (j_decompress_ptr cinfo)
917
INPUT_BYTE(cinfo, c, return FALSE);
918
/* Skip any non-FF bytes.
919
* This may look a bit inefficient, but it will not occur in a valid file.
920
* We sync after each discarded byte so that a suspending data source
921
* can discard the byte from its buffer.
924
cinfo->marker->discarded_bytes++;
926
INPUT_BYTE(cinfo, c, return FALSE);
928
/* This loop swallows any duplicate FF bytes. Extra FFs are legal as
929
* pad bytes, so don't count them in discarded_bytes. We assume there
930
* will not be so many consecutive FF bytes as to overflow a suspending
931
* data source's input buffer.
934
INPUT_BYTE(cinfo, c, return FALSE);
937
break; /* found a valid marker, exit loop */
938
/* Reach here if we found a stuffed-zero data sequence (FF/00).
939
* Discard it and loop back to try again.
941
cinfo->marker->discarded_bytes += 2;
945
if (cinfo->marker->discarded_bytes != 0) {
946
WARNMS2(cinfo, JWRN_EXTRANEOUS_DATA, cinfo->marker->discarded_bytes, c);
947
cinfo->marker->discarded_bytes = 0;
950
cinfo->unread_marker = c;
958
first_marker (j_decompress_ptr cinfo)
959
/* Like next_marker, but used to obtain the initial SOI marker. */
960
/* For this marker, we do not allow preceding garbage or fill; otherwise,
961
* we might well scan an entire input file before realizing it ain't JPEG.
962
* If an application wants to process non-JFIF files, it must seek to the
963
* SOI before calling the JPEG library.
969
INPUT_BYTE(cinfo, c, return FALSE);
970
INPUT_BYTE(cinfo, c2, return FALSE);
971
if (c != 0xFF || c2 != (int) M_SOI)
972
ERREXIT2(cinfo, JERR_NO_SOI, c, c2);
974
cinfo->unread_marker = c2;
982
* Read markers until SOS or EOI.
984
* Returns same codes as are defined for jpeg_consume_input:
985
* JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
987
* Note: This function may return a pseudo SOS marker (with zero
988
* component number) for treat by input controller's consume_input.
989
* consume_input itself should filter out (skip) the pseudo marker
990
* after processing for the caller.
994
read_markers (j_decompress_ptr cinfo)
996
/* Outer loop repeats once for each marker. */
998
/* Collect the marker proper, unless we already did. */
999
/* NB: first_marker() enforces the requirement that SOI appear first. */
1000
if (cinfo->unread_marker == 0) {
1001
if (! cinfo->marker->saw_SOI) {
1002
if (! first_marker(cinfo))
1003
return JPEG_SUSPENDED;
1005
if (! next_marker(cinfo))
1006
return JPEG_SUSPENDED;
1009
/* At this point cinfo->unread_marker contains the marker code and the
1010
* input point is just past the marker proper, but before any parameters.
1011
* A suspension will cause us to return with this state still true.
1013
switch (cinfo->unread_marker) {
1015
if (! get_soi(cinfo))
1016
return JPEG_SUSPENDED;
1019
case M_SOF0: /* Baseline */
1020
if (! get_sof(cinfo, TRUE, FALSE, FALSE))
1021
return JPEG_SUSPENDED;
1024
case M_SOF1: /* Extended sequential, Huffman */
1025
if (! get_sof(cinfo, FALSE, FALSE, FALSE))
1026
return JPEG_SUSPENDED;
1029
case M_SOF2: /* Progressive, Huffman */
1030
if (! get_sof(cinfo, FALSE, TRUE, FALSE))
1031
return JPEG_SUSPENDED;
1034
case M_SOF9: /* Extended sequential, arithmetic */
1035
if (! get_sof(cinfo, FALSE, FALSE, TRUE))
1036
return JPEG_SUSPENDED;
1039
case M_SOF10: /* Progressive, arithmetic */
1040
if (! get_sof(cinfo, FALSE, TRUE, TRUE))
1041
return JPEG_SUSPENDED;
1044
/* Currently unsupported SOFn types */
1045
case M_SOF3: /* Lossless, Huffman */
1046
case M_SOF5: /* Differential sequential, Huffman */
1047
case M_SOF6: /* Differential progressive, Huffman */
1048
case M_SOF7: /* Differential lossless, Huffman */
1049
case M_JPG: /* Reserved for JPEG extensions */
1050
case M_SOF11: /* Lossless, arithmetic */
1051
case M_SOF13: /* Differential sequential, arithmetic */
1052
case M_SOF14: /* Differential progressive, arithmetic */
1053
case M_SOF15: /* Differential lossless, arithmetic */
1054
ERREXIT1(cinfo, JERR_SOF_UNSUPPORTED, cinfo->unread_marker);
1058
if (! get_sos(cinfo))
1059
return JPEG_SUSPENDED;
1060
cinfo->unread_marker = 0; /* processed the marker */
1061
return JPEG_REACHED_SOS;
1064
TRACEMS(cinfo, 1, JTRC_EOI);
1065
cinfo->unread_marker = 0; /* processed the marker */
1066
return JPEG_REACHED_EOI;
1069
if (! get_dac(cinfo))
1070
return JPEG_SUSPENDED;
1074
if (! get_dht(cinfo))
1075
return JPEG_SUSPENDED;
1079
if (! get_dqt(cinfo))
1080
return JPEG_SUSPENDED;
1084
if (! get_dri(cinfo))
1085
return JPEG_SUSPENDED;
1104
if (! (*((my_marker_ptr) cinfo->marker)->process_APPn[
1105
cinfo->unread_marker - (int) M_APP0]) (cinfo))
1106
return JPEG_SUSPENDED;
1110
if (! (*((my_marker_ptr) cinfo->marker)->process_COM) (cinfo))
1111
return JPEG_SUSPENDED;
1114
case M_RST0: /* these are all parameterless */
1123
TRACEMS1(cinfo, 1, JTRC_PARMLESS_MARKER, cinfo->unread_marker);
1126
case M_DNL: /* Ignore DNL ... perhaps the wrong thing */
1127
if (! skip_variable(cinfo))
1128
return JPEG_SUSPENDED;
1131
default: /* must be DHP, EXP, JPGn, or RESn */
1132
/* For now, we treat the reserved markers as fatal errors since they are
1133
* likely to be used to signal incompatible JPEG Part 3 extensions.
1134
* Once the JPEG 3 version-number marker is well defined, this code
1137
ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
1140
/* Successfully processed marker, so reset state variable */
1141
cinfo->unread_marker = 0;
1147
* Read a restart marker, which is expected to appear next in the datastream;
1148
* if the marker is not there, take appropriate recovery action.
1149
* Returns FALSE if suspension is required.
1151
* This is called by the entropy decoder after it has read an appropriate
1152
* number of MCUs. cinfo->unread_marker may be nonzero if the entropy decoder
1153
* has already read a marker from the data source. Under normal conditions
1154
* cinfo->unread_marker will be reset to 0 before returning; if not reset,
1155
* it holds a marker which the decoder will be unable to read past.
1159
read_restart_marker (j_decompress_ptr cinfo)
1161
/* Obtain a marker unless we already did. */
1162
/* Note that next_marker will complain if it skips any data. */
1163
if (cinfo->unread_marker == 0) {
1164
if (! next_marker(cinfo))
1168
if (cinfo->unread_marker ==
1169
((int) M_RST0 + cinfo->marker->next_restart_num)) {
1170
/* Normal case --- swallow the marker and let entropy decoder continue */
1171
TRACEMS1(cinfo, 3, JTRC_RST, cinfo->marker->next_restart_num);
1172
cinfo->unread_marker = 0;
1174
/* Uh-oh, the restart markers have been messed up. */
1175
/* Let the data source manager determine how to resync. */
1176
if (! (*cinfo->src->resync_to_restart) (cinfo,
1177
cinfo->marker->next_restart_num))
1181
/* Update next-restart state */
1182
cinfo->marker->next_restart_num = (cinfo->marker->next_restart_num + 1) & 7;
1189
* This is the default resync_to_restart method for data source managers
1190
* to use if they don't have any better approach. Some data source managers
1191
* may be able to back up, or may have additional knowledge about the data
1192
* which permits a more intelligent recovery strategy; such managers would
1193
* presumably supply their own resync method.
1195
* read_restart_marker calls resync_to_restart if it finds a marker other than
1196
* the restart marker it was expecting. (This code is *not* used unless
1197
* a nonzero restart interval has been declared.) cinfo->unread_marker is
1198
* the marker code actually found (might be anything, except 0 or FF).
1199
* The desired restart marker number (0..7) is passed as a parameter.
1200
* This routine is supposed to apply whatever error recovery strategy seems
1201
* appropriate in order to position the input stream to the next data segment.
1202
* Note that cinfo->unread_marker is treated as a marker appearing before
1203
* the current data-source input point; usually it should be reset to zero
1205
* Returns FALSE if suspension is required.
1207
* This implementation is substantially constrained by wanting to treat the
1208
* input as a data stream; this means we can't back up. Therefore, we have
1209
* only the following actions to work with:
1210
* 1. Simply discard the marker and let the entropy decoder resume at next
1212
* 2. Read forward until we find another marker, discarding intervening
1213
* data. (In theory we could look ahead within the current bufferload,
1214
* without having to discard data if we don't find the desired marker.
1215
* This idea is not implemented here, in part because it makes behavior
1216
* dependent on buffer size and chance buffer-boundary positions.)
1217
* 3. Leave the marker unread (by failing to zero cinfo->unread_marker).
1218
* This will cause the entropy decoder to process an empty data segment,
1219
* inserting dummy zeroes, and then we will reprocess the marker.
1221
* #2 is appropriate if we think the desired marker lies ahead, while #3 is
1222
* appropriate if the found marker is a future restart marker (indicating
1223
* that we have missed the desired restart marker, probably because it got
1225
* We apply #2 or #3 if the found marker is a restart marker no more than
1226
* two counts behind or ahead of the expected one. We also apply #2 if the
1227
* found marker is not a legal JPEG marker code (it's certainly bogus data).
1228
* If the found marker is a restart marker more than 2 counts away, we do #1
1229
* (too much risk that the marker is erroneous; with luck we will be able to
1230
* resync at some future point).
1231
* For any valid non-restart JPEG marker, we apply #3. This keeps us from
1232
* overrunning the end of a scan. An implementation limited to single-scan
1233
* files might find it better to apply #2 for markers other than EOI, since
1234
* any other marker would have to be bogus data in that case.
1238
jpeg_resync_to_restart (j_decompress_ptr cinfo, int desired)
1240
int marker = cinfo->unread_marker;
1243
/* Always put up a warning. */
1244
WARNMS2(cinfo, JWRN_MUST_RESYNC, marker, desired);
1246
/* Outer loop handles repeated decision after scanning forward. */
1248
if (marker < (int) M_SOF0)
1249
action = 2; /* invalid marker */
1250
else if (marker < (int) M_RST0 || marker > (int) M_RST7)
1251
action = 3; /* valid non-restart marker */
1253
if (marker == ((int) M_RST0 + ((desired+1) & 7)) ||
1254
marker == ((int) M_RST0 + ((desired+2) & 7)))
1255
action = 3; /* one of the next two expected restarts */
1256
else if (marker == ((int) M_RST0 + ((desired-1) & 7)) ||
1257
marker == ((int) M_RST0 + ((desired-2) & 7)))
1258
action = 2; /* a prior restart, so advance */
1260
action = 1; /* desired restart or too far away */
1262
TRACEMS2(cinfo, 4, JTRC_RECOVERY_ACTION, marker, action);
1265
/* Discard marker and let entropy decoder resume processing. */
1266
cinfo->unread_marker = 0;
1269
/* Scan to the next marker, and repeat the decision loop. */
1270
if (! next_marker(cinfo))
1272
marker = cinfo->unread_marker;
1275
/* Return without advancing past this marker. */
1276
/* Entropy decoder will be forced to process an empty segment. */
1284
* Reset marker processing state to begin a fresh datastream.
1288
reset_marker_reader (j_decompress_ptr cinfo)
1290
my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1292
cinfo->comp_info = NULL; /* until allocated by get_sof */
1293
cinfo->input_scan_number = 0; /* no SOS seen yet */
1294
cinfo->unread_marker = 0; /* no pending marker */
1295
marker->pub.saw_SOI = FALSE; /* set internal state too */
1296
marker->pub.saw_SOF = FALSE;
1297
marker->pub.discarded_bytes = 0;
1298
marker->cur_marker = NULL;
1303
* Initialize the marker reader module.
1304
* This is called only once, when the decompression object is created.
1308
jinit_marker_reader (j_decompress_ptr cinfo)
1310
my_marker_ptr marker;
1313
/* Create subobject in permanent pool */
1314
marker = (my_marker_ptr)
1315
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
1316
SIZEOF(my_marker_reader));
1317
cinfo->marker = (struct jpeg_marker_reader *) marker;
1318
/* Initialize public method pointers */
1319
marker->pub.reset_marker_reader = reset_marker_reader;
1320
marker->pub.read_markers = read_markers;
1321
marker->pub.read_restart_marker = read_restart_marker;
1322
/* Initialize COM/APPn processing.
1323
* By default, we examine and then discard APP0 and APP14,
1324
* but simply discard COM and all other APPn.
1326
marker->process_COM = skip_variable;
1327
marker->length_limit_COM = 0;
1328
for (i = 0; i < 16; i++) {
1329
marker->process_APPn[i] = skip_variable;
1330
marker->length_limit_APPn[i] = 0;
1332
marker->process_APPn[0] = get_interesting_appn;
1333
marker->process_APPn[14] = get_interesting_appn;
1334
/* Reset marker processing state */
1335
reset_marker_reader(cinfo);
1340
* Control saving of COM and APPn markers into marker_list.
1343
#ifdef SAVE_MARKERS_SUPPORTED
1346
jpeg_save_markers (j_decompress_ptr cinfo, int marker_code,
1347
unsigned int length_limit)
1349
my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1351
jpeg_marker_parser_method processor;
1353
/* Length limit mustn't be larger than what we can allocate
1354
* (should only be a concern in a 16-bit environment).
1356
maxlength = cinfo->mem->max_alloc_chunk - SIZEOF(struct jpeg_marker_struct);
1357
if (((long) length_limit) > maxlength)
1358
length_limit = (unsigned int) maxlength;
1360
/* Choose processor routine to use.
1361
* APP0/APP14 have special requirements.
1364
processor = save_marker;
1365
/* If saving APP0/APP14, save at least enough for our internal use. */
1366
if (marker_code == (int) M_APP0 && length_limit < APP0_DATA_LEN)
1367
length_limit = APP0_DATA_LEN;
1368
else if (marker_code == (int) M_APP14 && length_limit < APP14_DATA_LEN)
1369
length_limit = APP14_DATA_LEN;
1371
processor = skip_variable;
1372
/* If discarding APP0/APP14, use our regular on-the-fly processor. */
1373
if (marker_code == (int) M_APP0 || marker_code == (int) M_APP14)
1374
processor = get_interesting_appn;
1377
if (marker_code == (int) M_COM) {
1378
marker->process_COM = processor;
1379
marker->length_limit_COM = length_limit;
1380
} else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15) {
1381
marker->process_APPn[marker_code - (int) M_APP0] = processor;
1382
marker->length_limit_APPn[marker_code - (int) M_APP0] = length_limit;
1384
ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
1387
#endif /* SAVE_MARKERS_SUPPORTED */
1391
* Install a special processing method for COM or APPn markers.
1395
jpeg_set_marker_processor (j_decompress_ptr cinfo, int marker_code,
1396
jpeg_marker_parser_method routine)
1398
my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1400
if (marker_code == (int) M_COM)
1401
marker->process_COM = routine;
1402
else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15)
1403
marker->process_APPn[marker_code - (int) M_APP0] = routine;
1405
ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
added
removed
jpg/jdmarker.c
