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.
8
* This file contains routines to decode JPEG datastream markers.
9
* Most of the complexity arises from our desire to support input
10
* suspension: if not all of the data for a marker is available,
11
* we must exit back to the application. On resumption, we reprocess
15
#define JPEG_INTERNALS
20
typedef enum { /* JPEG marker codes */
91
struct jpeg_marker_reader pub; /* public fields */
93
/* Application-overridable marker processing methods */
94
jpeg_marker_parser_method process_COM;
95
jpeg_marker_parser_method process_APPn[16];
97
/* Limit on marker data length to save for each marker type */
98
unsigned int length_limit_COM;
99
unsigned int length_limit_APPn[16];
101
/* Status of COM/APPn marker saving */
102
jpeg_saved_marker_ptr cur_marker; /* NULL if not processing a marker */
103
unsigned int bytes_read; /* data bytes read so far in marker */
104
/* Note: cur_marker is not linked into marker_list until it's all read. */
107
typedef my_marker_reader * my_marker_ptr;
111
* Macros for fetching data from the data source module.
113
* At all times, cinfo->src->next_input_byte and ->bytes_in_buffer reflect
114
* the current restart point; we update them only when we have reached a
115
* suitable place to restart if a suspension occurs.
118
/* Declare and initialize local copies of input pointer/count */
119
#define INPUT_VARS(cinfo) \
120
struct jpeg_source_mgr * datasrc = (cinfo)->src; \
121
const JOCTET * next_input_byte = datasrc->next_input_byte; \
122
size_t bytes_in_buffer = datasrc->bytes_in_buffer
124
/* Unload the local copies --- do this only at a restart boundary */
125
#define INPUT_SYNC(cinfo) \
126
( datasrc->next_input_byte = next_input_byte, \
127
datasrc->bytes_in_buffer = bytes_in_buffer )
129
/* Reload the local copies --- used only in MAKE_BYTE_AVAIL */
130
#define INPUT_RELOAD(cinfo) \
131
( next_input_byte = datasrc->next_input_byte, \
132
bytes_in_buffer = datasrc->bytes_in_buffer )
134
/* Internal macro for INPUT_BYTE and INPUT_2BYTES: make a byte available.
135
* Note we do *not* do INPUT_SYNC before calling fill_input_buffer,
136
* but we must reload the local copies after a successful fill.
138
#define MAKE_BYTE_AVAIL(cinfo,action) \
139
if (bytes_in_buffer == 0) { \
140
if (! (*datasrc->fill_input_buffer) (cinfo)) \
142
INPUT_RELOAD(cinfo); \
145
/* Read a byte into variable V.
146
* If must suspend, take the specified action (typically "return FALSE").
148
#define INPUT_BYTE(cinfo,V,action) \
149
MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \
151
V = GETJOCTET(*next_input_byte++); )
153
/* As above, but read two bytes interpreted as an unsigned 16-bit integer.
154
* V should be declared unsigned int or perhaps INT32.
156
#define INPUT_2BYTES(cinfo,V,action) \
157
MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \
159
V = ((unsigned int) GETJOCTET(*next_input_byte++)) << 8; \
160
MAKE_BYTE_AVAIL(cinfo,action); \
162
V += GETJOCTET(*next_input_byte++); )
166
* Routines to process JPEG markers.
168
* Entry condition: JPEG marker itself has been read and its code saved
169
* in cinfo->unread_marker; input restart point is just after the marker.
171
* Exit: if return TRUE, have read and processed any parameters, and have
172
* updated the restart point to point after the parameters.
173
* If return FALSE, was forced to suspend before reaching end of
174
* marker parameters; restart point has not been moved. Same routine
175
* will be called again after application supplies more input data.
177
* This approach to suspension assumes that all of a marker's parameters
178
* can fit into a single input bufferload. This should hold for "normal"
179
* markers. Some COM/APPn markers might have large parameter segments
180
* that might not fit. If we are simply dropping such a marker, we use
181
* skip_input_data to get past it, and thereby put the problem on the
182
* source manager's shoulders. If we are saving the marker's contents
183
* into memory, we use a slightly different convention: when forced to
184
* suspend, the marker processor updates the restart point to the end of
185
* what it's consumed (ie, the end of the buffer) before returning FALSE.
186
* On resumption, cinfo->unread_marker still contains the marker code,
187
* but the data source will point to the next chunk of marker data.
188
* The marker processor must retain internal state to deal with this.
190
* Note that we don't bother to avoid duplicate trace messages if a
191
* suspension occurs within marker parameters. Other side effects
196
LOCAL(wxjpeg_boolean)
197
get_soi (j_decompress_ptr cinfo)
198
/* Process an SOI marker */
202
TRACEMS(cinfo, 1, JTRC_SOI);
204
if (cinfo->marker->saw_SOI)
205
ERREXIT(cinfo, JERR_SOI_DUPLICATE);
207
/* Reset all parameters that are defined to be reset by SOI */
209
for (i = 0; i < NUM_ARITH_TBLS; i++) {
210
cinfo->arith_dc_L[i] = 0;
211
cinfo->arith_dc_U[i] = 1;
212
cinfo->arith_ac_K[i] = 5;
214
cinfo->restart_interval = 0;
216
/* Set initial assumptions for colorspace etc */
218
cinfo->jpeg_color_space = JCS_UNKNOWN;
219
cinfo->CCIR601_sampling = FALSE; /* Assume non-CCIR sampling??? */
221
cinfo->saw_JFIF_marker = FALSE;
222
cinfo->JFIF_major_version = 1; /* set default JFIF APP0 values */
223
cinfo->JFIF_minor_version = 1;
224
cinfo->density_unit = 0;
225
cinfo->X_density = 1;
226
cinfo->Y_density = 1;
227
cinfo->saw_Adobe_marker = FALSE;
228
cinfo->Adobe_transform = 0;
230
cinfo->marker->saw_SOI = TRUE;
236
LOCAL(wxjpeg_boolean)
237
get_sof (j_decompress_ptr cinfo, wxjpeg_boolean is_prog, wxjpeg_boolean is_arith)
238
/* Process a SOFn marker */
242
jpeg_component_info * compptr;
245
cinfo->progressive_mode = is_prog;
246
cinfo->arith_code = is_arith;
248
INPUT_2BYTES(cinfo, length, return FALSE);
250
INPUT_BYTE(cinfo, cinfo->data_precision, return FALSE);
251
INPUT_2BYTES(cinfo, cinfo->image_height, return FALSE);
252
INPUT_2BYTES(cinfo, cinfo->image_width, return FALSE);
253
INPUT_BYTE(cinfo, cinfo->num_components, return FALSE);
257
TRACEMS4(cinfo, 1, JTRC_SOF, cinfo->unread_marker,
258
(int) cinfo->image_width, (int) cinfo->image_height,
259
cinfo->num_components);
261
if (cinfo->marker->saw_SOF)
262
ERREXIT(cinfo, JERR_SOF_DUPLICATE);
264
/* We don't support files in which the image height is initially specified */
265
/* as 0 and is later redefined by DNL. As long as we have to check that, */
266
/* might as well have a general sanity check. */
267
if (cinfo->image_height <= 0 || cinfo->image_width <= 0
268
|| cinfo->num_components <= 0)
269
ERREXIT(cinfo, JERR_EMPTY_IMAGE);
271
if (length != (cinfo->num_components * 3))
272
ERREXIT(cinfo, JERR_BAD_LENGTH);
274
if (cinfo->comp_info == NULL) /* do only once, even if suspend */
275
cinfo->comp_info = (jpeg_component_info *) (*cinfo->mem->alloc_small)
276
((j_common_ptr) cinfo, JPOOL_IMAGE,
277
cinfo->num_components * SIZEOF(jpeg_component_info));
279
for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
281
compptr->component_index = ci;
282
INPUT_BYTE(cinfo, compptr->component_id, return FALSE);
283
INPUT_BYTE(cinfo, c, return FALSE);
284
compptr->h_samp_factor = (c >> 4) & 15;
285
compptr->v_samp_factor = (c ) & 15;
286
INPUT_BYTE(cinfo, compptr->quant_tbl_no, return FALSE);
288
TRACEMS4(cinfo, 1, JTRC_SOF_COMPONENT,
289
compptr->component_id, compptr->h_samp_factor,
290
compptr->v_samp_factor, compptr->quant_tbl_no);
293
cinfo->marker->saw_SOF = TRUE;
300
LOCAL(wxjpeg_boolean)
301
get_sos (j_decompress_ptr cinfo)
302
/* Process a SOS marker */
306
jpeg_component_info * compptr;
309
if (! cinfo->marker->saw_SOF)
310
ERREXIT(cinfo, JERR_SOS_NO_SOF);
312
INPUT_2BYTES(cinfo, length, return FALSE);
314
INPUT_BYTE(cinfo, n, return FALSE); /* Number of components */
316
TRACEMS1(cinfo, 1, JTRC_SOS, n);
318
if (length != (n * 2 + 6) || n < 1 || n > MAX_COMPS_IN_SCAN)
319
ERREXIT(cinfo, JERR_BAD_LENGTH);
321
cinfo->comps_in_scan = n;
323
/* Collect the component-spec parameters */
325
for (i = 0; i < n; i++) {
326
INPUT_BYTE(cinfo, cc, return FALSE);
327
INPUT_BYTE(cinfo, c, return FALSE);
329
for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
331
if (cc == compptr->component_id)
335
ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc);
339
cinfo->cur_comp_info[i] = compptr;
340
compptr->dc_tbl_no = (c >> 4) & 15;
341
compptr->ac_tbl_no = (c ) & 15;
343
TRACEMS3(cinfo, 1, JTRC_SOS_COMPONENT, cc,
344
compptr->dc_tbl_no, compptr->ac_tbl_no);
347
/* Collect the additional scan parameters Ss, Se, Ah/Al. */
348
INPUT_BYTE(cinfo, c, return FALSE);
350
INPUT_BYTE(cinfo, c, return FALSE);
352
INPUT_BYTE(cinfo, c, return FALSE);
353
cinfo->Ah = (c >> 4) & 15;
354
cinfo->Al = (c ) & 15;
356
TRACEMS4(cinfo, 1, JTRC_SOS_PARAMS, cinfo->Ss, cinfo->Se,
357
cinfo->Ah, cinfo->Al);
359
/* Prepare to scan data & restart markers */
360
cinfo->marker->next_restart_num = 0;
362
/* Count another SOS marker */
363
cinfo->input_scan_number++;
370
#ifdef D_ARITH_CODING_SUPPORTED
372
LOCAL(wxjpeg_boolean)
373
get_dac (j_decompress_ptr cinfo)
374
/* Process a DAC marker */
380
INPUT_2BYTES(cinfo, length, return FALSE);
384
INPUT_BYTE(cinfo, index, return FALSE);
385
INPUT_BYTE(cinfo, val, return FALSE);
389
TRACEMS2(cinfo, 1, JTRC_DAC, index, val);
391
if (index < 0 || index >= (2*NUM_ARITH_TBLS))
392
ERREXIT1(cinfo, JERR_DAC_INDEX, index);
394
if (index >= NUM_ARITH_TBLS) { /* define AC table */
395
cinfo->arith_ac_K[index-NUM_ARITH_TBLS] = (UINT8) val;
396
} else { /* define DC table */
397
cinfo->arith_dc_L[index] = (UINT8) (val & 0x0F);
398
cinfo->arith_dc_U[index] = (UINT8) (val >> 4);
399
if (cinfo->arith_dc_L[index] > cinfo->arith_dc_U[index])
400
ERREXIT1(cinfo, JERR_DAC_VALUE, val);
405
ERREXIT(cinfo, JERR_BAD_LENGTH);
411
#else /* ! D_ARITH_CODING_SUPPORTED */
413
#define get_dac(cinfo) skip_variable(cinfo)
415
#endif /* D_ARITH_CODING_SUPPORTED */
418
LOCAL(wxjpeg_boolean)
419
get_dht (j_decompress_ptr cinfo)
420
/* Process a DHT marker */
429
INPUT_2BYTES(cinfo, length, return FALSE);
432
while (length > 16) {
433
INPUT_BYTE(cinfo, index, return FALSE);
435
TRACEMS1(cinfo, 1, JTRC_DHT, index);
439
for (i = 1; i <= 16; i++) {
440
INPUT_BYTE(cinfo, bits[i], return FALSE);
446
TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
447
bits[1], bits[2], bits[3], bits[4],
448
bits[5], bits[6], bits[7], bits[8]);
449
TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
450
bits[9], bits[10], bits[11], bits[12],
451
bits[13], bits[14], bits[15], bits[16]);
453
/* Here we just do minimal validation of the counts to avoid walking
454
* off the end of our table space. jdhuff.c will check more carefully.
456
if (count > 256 || ((JPEG_INT32) count) > length)
457
ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
459
for (i = 0; i < count; i++)
460
INPUT_BYTE(cinfo, huffval[i], return FALSE);
464
if (index & 0x10) { /* AC table definition */
466
htblptr = &cinfo->ac_huff_tbl_ptrs[index];
467
} else { /* DC table definition */
468
htblptr = &cinfo->dc_huff_tbl_ptrs[index];
471
if (index < 0 || index >= NUM_HUFF_TBLS)
472
ERREXIT1(cinfo, JERR_DHT_INDEX, index);
474
if (*htblptr == NULL)
475
*htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
477
MEMCOPY((*htblptr)->bits, bits, SIZEOF((*htblptr)->bits));
478
MEMCOPY((*htblptr)->huffval, huffval, SIZEOF((*htblptr)->huffval));
482
ERREXIT(cinfo, JERR_BAD_LENGTH);
489
LOCAL(wxjpeg_boolean)
490
get_dqt (j_decompress_ptr cinfo)
491
/* Process a DQT marker */
496
JQUANT_TBL *quant_ptr;
499
INPUT_2BYTES(cinfo, length, return FALSE);
503
INPUT_BYTE(cinfo, n, return FALSE);
507
TRACEMS2(cinfo, 1, JTRC_DQT, n, prec);
509
if (n >= NUM_QUANT_TBLS)
510
ERREXIT1(cinfo, JERR_DQT_INDEX, n);
512
if (cinfo->quant_tbl_ptrs[n] == NULL)
513
cinfo->quant_tbl_ptrs[n] = jpeg_alloc_quant_table((j_common_ptr) cinfo);
514
quant_ptr = cinfo->quant_tbl_ptrs[n];
516
for (i = 0; i < DCTSIZE2; i++) {
518
INPUT_2BYTES(cinfo, tmp, return FALSE);
520
INPUT_BYTE(cinfo, tmp, return FALSE);
521
/* We convert the zigzag-order table to natural array order. */
522
quant_ptr->quantval[jpeg_natural_order[i]] = (UINT16) tmp;
525
if (cinfo->err->trace_level >= 2) {
526
for (i = 0; i < DCTSIZE2; i += 8) {
527
TRACEMS8(cinfo, 2, JTRC_QUANTVALS,
528
quant_ptr->quantval[i], quant_ptr->quantval[i+1],
529
quant_ptr->quantval[i+2], quant_ptr->quantval[i+3],
530
quant_ptr->quantval[i+4], quant_ptr->quantval[i+5],
531
quant_ptr->quantval[i+6], quant_ptr->quantval[i+7]);
535
length -= DCTSIZE2+1;
536
if (prec) length -= DCTSIZE2;
540
ERREXIT(cinfo, JERR_BAD_LENGTH);
547
LOCAL(wxjpeg_boolean)
548
get_dri (j_decompress_ptr cinfo)
549
/* Process a DRI marker */
555
INPUT_2BYTES(cinfo, length, return FALSE);
558
ERREXIT(cinfo, JERR_BAD_LENGTH);
560
INPUT_2BYTES(cinfo, tmp, return FALSE);
562
TRACEMS1(cinfo, 1, JTRC_DRI, tmp);
564
cinfo->restart_interval = tmp;
572
* Routines for processing APPn and COM markers.
573
* These are either saved in memory or discarded, per application request.
574
* APP0 and APP14 are specially checked to see if they are
575
* JFIF and Adobe markers, respectively.
578
#define APP0_DATA_LEN 14 /* Length of interesting data in APP0 */
579
#define APP14_DATA_LEN 12 /* Length of interesting data in APP14 */
580
#define APPN_DATA_LEN 14 /* Must be the largest of the above!! */
584
examine_app0 (j_decompress_ptr cinfo, JOCTET FAR * data,
585
unsigned int datalen, JPEG_INT32 remaining)
586
/* Examine first few bytes from an APP0.
587
* Take appropriate action if it is a JFIF marker.
588
* datalen is # of bytes at data[], remaining is length of rest of marker data.
591
JPEG_INT32 totallen = (JPEG_INT32) datalen + remaining;
593
if (datalen >= APP0_DATA_LEN &&
594
GETJOCTET(data[0]) == 0x4A &&
595
GETJOCTET(data[1]) == 0x46 &&
596
GETJOCTET(data[2]) == 0x49 &&
597
GETJOCTET(data[3]) == 0x46 &&
598
GETJOCTET(data[4]) == 0) {
599
/* Found JFIF APP0 marker: save info */
600
cinfo->saw_JFIF_marker = TRUE;
601
cinfo->JFIF_major_version = GETJOCTET(data[5]);
602
cinfo->JFIF_minor_version = GETJOCTET(data[6]);
603
cinfo->density_unit = GETJOCTET(data[7]);
604
cinfo->X_density = (GETJOCTET(data[8]) << 8) + GETJOCTET(data[9]);
605
cinfo->Y_density = (GETJOCTET(data[10]) << 8) + GETJOCTET(data[11]);
607
* Major version must be 1, anything else signals an incompatible change.
608
* (We used to treat this as an error, but now it's a nonfatal warning,
609
* because some bozo at Hijaak couldn't read the spec.)
610
* Minor version should be 0..2, but process anyway if newer.
612
if (cinfo->JFIF_major_version != 1)
613
WARNMS2(cinfo, JWRN_JFIF_MAJOR,
614
cinfo->JFIF_major_version, cinfo->JFIF_minor_version);
615
/* Generate trace messages */
616
TRACEMS5(cinfo, 1, JTRC_JFIF,
617
cinfo->JFIF_major_version, cinfo->JFIF_minor_version,
618
cinfo->X_density, cinfo->Y_density, cinfo->density_unit);
619
/* Validate thumbnail dimensions and issue appropriate messages */
620
if (GETJOCTET(data[12]) | GETJOCTET(data[13]))
621
TRACEMS2(cinfo, 1, JTRC_JFIF_THUMBNAIL,
622
GETJOCTET(data[12]), GETJOCTET(data[13]));
623
totallen -= APP0_DATA_LEN;
625
((JPEG_INT32)GETJOCTET(data[12]) * (JPEG_INT32)GETJOCTET(data[13]) * (JPEG_INT32) 3))
626
TRACEMS1(cinfo, 1, JTRC_JFIF_BADTHUMBNAILSIZE, (int) totallen);
627
} else if (datalen >= 6 &&
628
GETJOCTET(data[0]) == 0x4A &&
629
GETJOCTET(data[1]) == 0x46 &&
630
GETJOCTET(data[2]) == 0x58 &&
631
GETJOCTET(data[3]) == 0x58 &&
632
GETJOCTET(data[4]) == 0) {
633
/* Found JFIF "JFXX" extension APP0 marker */
634
/* The library doesn't actually do anything with these,
635
* but we try to produce a helpful trace message.
637
switch (GETJOCTET(data[5])) {
639
TRACEMS1(cinfo, 1, JTRC_THUMB_JPEG, (int) totallen);
642
TRACEMS1(cinfo, 1, JTRC_THUMB_PALETTE, (int) totallen);
645
TRACEMS1(cinfo, 1, JTRC_THUMB_RGB, (int) totallen);
648
TRACEMS2(cinfo, 1, JTRC_JFIF_EXTENSION,
649
GETJOCTET(data[5]), (int) totallen);
653
/* Start of APP0 does not match "JFIF" or "JFXX", or too short */
654
TRACEMS1(cinfo, 1, JTRC_APP0, (int) totallen);
660
examine_app14 (j_decompress_ptr cinfo, JOCTET FAR * data,
661
unsigned int datalen, JPEG_INT32 remaining)
662
/* Examine first few bytes from an APP14.
663
* Take appropriate action if it is an Adobe marker.
664
* datalen is # of bytes at data[], remaining is length of rest of marker data.
667
unsigned int version, flags0, flags1, transform;
669
if (datalen >= APP14_DATA_LEN &&
670
GETJOCTET(data[0]) == 0x41 &&
671
GETJOCTET(data[1]) == 0x64 &&
672
GETJOCTET(data[2]) == 0x6F &&
673
GETJOCTET(data[3]) == 0x62 &&
674
GETJOCTET(data[4]) == 0x65) {
675
/* Found Adobe APP14 marker */
676
version = (GETJOCTET(data[5]) << 8) + GETJOCTET(data[6]);
677
flags0 = (GETJOCTET(data[7]) << 8) + GETJOCTET(data[8]);
678
flags1 = (GETJOCTET(data[9]) << 8) + GETJOCTET(data[10]);
679
transform = GETJOCTET(data[11]);
680
TRACEMS4(cinfo, 1, JTRC_ADOBE, version, flags0, flags1, transform);
681
cinfo->saw_Adobe_marker = TRUE;
682
cinfo->Adobe_transform = (UINT8) transform;
684
/* Start of APP14 does not match "Adobe", or too short */
685
TRACEMS1(cinfo, 1, JTRC_APP14, (int) (datalen + remaining));
690
METHODDEF(wxjpeg_boolean)
691
get_interesting_appn (j_decompress_ptr cinfo)
692
/* Process an APP0 or APP14 marker without saving it */
695
JOCTET b[APPN_DATA_LEN];
696
unsigned int i, numtoread;
699
INPUT_2BYTES(cinfo, length, return FALSE);
702
/* get the interesting part of the marker data */
703
if (length >= APPN_DATA_LEN)
704
numtoread = APPN_DATA_LEN;
706
numtoread = (unsigned int) length;
709
for (i = 0; i < numtoread; i++)
710
INPUT_BYTE(cinfo, b[i], return FALSE);
714
switch (cinfo->unread_marker) {
716
examine_app0(cinfo, (JOCTET FAR *) b, numtoread, length);
719
examine_app14(cinfo, (JOCTET FAR *) b, numtoread, length);
722
/* can't get here unless jpeg_save_markers chooses wrong processor */
723
ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
727
/* skip any remaining data -- could be lots */
730
(*cinfo->src->skip_input_data) (cinfo, (long) length);
736
#ifdef SAVE_MARKERS_SUPPORTED
738
METHODDEF(wxjpeg_boolean)
739
save_marker (j_decompress_ptr cinfo)
740
/* Save an APPn or COM marker into the marker list */
742
my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
743
jpeg_saved_marker_ptr cur_marker = marker->cur_marker;
744
unsigned int bytes_read, data_length;
746
JPEG_INT32 length = 0;
749
if (cur_marker == NULL) {
750
/* begin reading a marker */
751
INPUT_2BYTES(cinfo, length, return FALSE);
753
if (length >= 0) { /* watch out for bogus length word */
754
/* figure out how much we want to save */
756
if (cinfo->unread_marker == (int) M_COM)
757
limit = marker->length_limit_COM;
759
limit = marker->length_limit_APPn[cinfo->unread_marker - (int) M_APP0];
760
if ((unsigned int) length < limit)
761
limit = (unsigned int) length;
762
/* allocate and initialize the marker item */
763
cur_marker = (jpeg_saved_marker_ptr)
764
(*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
765
SIZEOF(struct jpeg_marker_struct) + limit);
766
cur_marker->next = NULL;
767
cur_marker->marker = (UINT8) cinfo->unread_marker;
768
cur_marker->original_length = (unsigned int) length;
769
cur_marker->data_length = limit;
770
/* data area is just beyond the jpeg_marker_struct */
771
data = cur_marker->data = (JOCTET FAR *) (cur_marker + 1);
772
marker->cur_marker = cur_marker;
773
marker->bytes_read = 0;
777
/* deal with bogus length word */
778
bytes_read = data_length = 0;
782
/* resume reading a marker */
783
bytes_read = marker->bytes_read;
784
data_length = cur_marker->data_length;
785
data = cur_marker->data + bytes_read;
788
while (bytes_read < data_length) {
789
INPUT_SYNC(cinfo); /* move the restart point to here */
790
marker->bytes_read = bytes_read;
791
/* If there's not at least one byte in buffer, suspend */
792
MAKE_BYTE_AVAIL(cinfo, return FALSE);
793
/* Copy bytes with reasonable rapidity */
794
while (bytes_read < data_length && bytes_in_buffer > 0) {
795
*data++ = *next_input_byte++;
801
/* Done reading what we want to read */
802
if (cur_marker != NULL) { /* will be NULL if bogus length word */
803
/* Add new marker to end of list */
804
if (cinfo->marker_list == NULL) {
805
cinfo->marker_list = cur_marker;
807
jpeg_saved_marker_ptr prev = cinfo->marker_list;
808
while (prev->next != NULL)
810
prev->next = cur_marker;
812
/* Reset pointer & calc remaining data length */
813
data = cur_marker->data;
814
length = cur_marker->original_length - data_length;
816
/* Reset to initial state for next marker */
817
marker->cur_marker = NULL;
819
/* Process the marker if interesting; else just make a generic trace msg */
820
switch (cinfo->unread_marker) {
822
examine_app0(cinfo, data, data_length, length);
825
examine_app14(cinfo, data, data_length, length);
828
TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker,
829
(int) (data_length + length));
833
/* skip any remaining data -- could be lots */
834
INPUT_SYNC(cinfo); /* do before skip_input_data */
836
(*cinfo->src->skip_input_data) (cinfo, (long) length);
841
#endif /* SAVE_MARKERS_SUPPORTED */
844
METHODDEF(wxjpeg_boolean)
845
skip_variable (j_decompress_ptr cinfo)
846
/* Skip over an unknown or uninteresting variable-length marker */
851
INPUT_2BYTES(cinfo, length, return FALSE);
854
TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, (int) length);
856
INPUT_SYNC(cinfo); /* do before skip_input_data */
858
(*cinfo->src->skip_input_data) (cinfo, (long) length);
865
* Find the next JPEG marker, save it in cinfo->unread_marker.
866
* Returns FALSE if had to suspend before reaching a marker;
867
* in that case cinfo->unread_marker is unchanged.
869
* Note that the result might not be a valid marker code,
870
* but it will never be 0 or FF.
873
LOCAL(wxjpeg_boolean)
874
next_marker (j_decompress_ptr cinfo)
880
INPUT_BYTE(cinfo, c, return FALSE);
881
/* Skip any non-FF bytes.
882
* This may look a bit inefficient, but it will not occur in a valid file.
883
* We sync after each discarded byte so that a suspending data source
884
* can discard the byte from its buffer.
887
cinfo->marker->discarded_bytes++;
889
INPUT_BYTE(cinfo, c, return FALSE);
891
/* This loop swallows any duplicate FF bytes. Extra FFs are legal as
892
* pad bytes, so don't count them in discarded_bytes. We assume there
893
* will not be so many consecutive FF bytes as to overflow a suspending
894
* data source's input buffer.
897
INPUT_BYTE(cinfo, c, return FALSE);
900
break; /* found a valid marker, exit loop */
901
/* Reach here if we found a stuffed-zero data sequence (FF/00).
902
* Discard it and loop back to try again.
904
cinfo->marker->discarded_bytes += 2;
908
if (cinfo->marker->discarded_bytes != 0) {
909
WARNMS2(cinfo, JWRN_EXTRANEOUS_DATA, cinfo->marker->discarded_bytes, c);
910
cinfo->marker->discarded_bytes = 0;
913
cinfo->unread_marker = c;
920
LOCAL(wxjpeg_boolean)
921
first_marker (j_decompress_ptr cinfo)
922
/* Like next_marker, but used to obtain the initial SOI marker. */
923
/* For this marker, we do not allow preceding garbage or fill; otherwise,
924
* we might well scan an entire input file before realizing it ain't JPEG.
925
* If an application wants to process non-JFIF files, it must seek to the
926
* SOI before calling the JPEG library.
932
INPUT_BYTE(cinfo, c, return FALSE);
933
INPUT_BYTE(cinfo, c2, return FALSE);
934
if (c != 0xFF || c2 != (int) M_SOI)
935
ERREXIT2(cinfo, JERR_NO_SOI, c, c2);
937
cinfo->unread_marker = c2;
945
* Read markers until SOS or EOI.
947
* Returns same codes as are defined for jpeg_consume_input:
948
* JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
952
read_markers (j_decompress_ptr cinfo)
954
/* Outer loop repeats once for each marker. */
956
/* Collect the marker proper, unless we already did. */
957
/* NB: first_marker() enforces the requirement that SOI appear first. */
958
if (cinfo->unread_marker == 0) {
959
if (! cinfo->marker->saw_SOI) {
960
if (! first_marker(cinfo))
961
return JPEG_SUSPENDED;
963
if (! next_marker(cinfo))
964
return JPEG_SUSPENDED;
967
/* At this point cinfo->unread_marker contains the marker code and the
968
* input point is just past the marker proper, but before any parameters.
969
* A suspension will cause us to return with this state still true.
971
switch (cinfo->unread_marker) {
973
if (! get_soi(cinfo))
974
return JPEG_SUSPENDED;
977
case M_SOF0: /* Baseline */
978
case M_SOF1: /* Extended sequential, Huffman */
979
if (! get_sof(cinfo, FALSE, FALSE))
980
return JPEG_SUSPENDED;
983
case M_SOF2: /* Progressive, Huffman */
984
if (! get_sof(cinfo, TRUE, FALSE))
985
return JPEG_SUSPENDED;
988
case M_SOF9: /* Extended sequential, arithmetic */
989
if (! get_sof(cinfo, FALSE, TRUE))
990
return JPEG_SUSPENDED;
993
case M_SOF10: /* Progressive, arithmetic */
994
if (! get_sof(cinfo, TRUE, TRUE))
995
return JPEG_SUSPENDED;
998
/* Currently unsupported SOFn types */
999
case M_SOF3: /* Lossless, Huffman */
1000
case M_SOF5: /* Differential sequential, Huffman */
1001
case M_SOF6: /* Differential progressive, Huffman */
1002
case M_SOF7: /* Differential lossless, Huffman */
1003
case M_JPG: /* Reserved for JPEG extensions */
1004
case M_SOF11: /* Lossless, arithmetic */
1005
case M_SOF13: /* Differential sequential, arithmetic */
1006
case M_SOF14: /* Differential progressive, arithmetic */
1007
case M_SOF15: /* Differential lossless, arithmetic */
1008
ERREXIT1(cinfo, JERR_SOF_UNSUPPORTED, cinfo->unread_marker);
1012
if (! get_sos(cinfo))
1013
return JPEG_SUSPENDED;
1014
cinfo->unread_marker = 0; /* processed the marker */
1015
return JPEG_REACHED_SOS;
1018
TRACEMS(cinfo, 1, JTRC_EOI);
1019
cinfo->unread_marker = 0; /* processed the marker */
1020
return JPEG_REACHED_EOI;
1023
if (! get_dac(cinfo))
1024
return JPEG_SUSPENDED;
1028
if (! get_dht(cinfo))
1029
return JPEG_SUSPENDED;
1033
if (! get_dqt(cinfo))
1034
return JPEG_SUSPENDED;
1038
if (! get_dri(cinfo))
1039
return JPEG_SUSPENDED;
1058
if (! (*((my_marker_ptr) cinfo->marker)->process_APPn[
1059
cinfo->unread_marker - (int) M_APP0]) (cinfo))
1060
return JPEG_SUSPENDED;
1064
if (! (*((my_marker_ptr) cinfo->marker)->process_COM) (cinfo))
1065
return JPEG_SUSPENDED;
1068
case M_RST0: /* these are all parameterless */
1077
TRACEMS1(cinfo, 1, JTRC_PARMLESS_MARKER, cinfo->unread_marker);
1080
case M_DNL: /* Ignore DNL ... perhaps the wrong thing */
1081
if (! skip_variable(cinfo))
1082
return JPEG_SUSPENDED;
1085
default: /* must be DHP, EXP, JPGn, or RESn */
1086
/* For now, we treat the reserved markers as fatal errors since they are
1087
* likely to be used to signal incompatible JPEG Part 3 extensions.
1088
* Once the JPEG 3 version-number marker is well defined, this code
1091
ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
1094
/* Successfully processed marker, so reset state variable */
1095
cinfo->unread_marker = 0;
1101
* Read a restart marker, which is expected to appear next in the datastream;
1102
* if the marker is not there, take appropriate recovery action.
1103
* Returns FALSE if suspension is required.
1105
* This is called by the entropy decoder after it has read an appropriate
1106
* number of MCUs. cinfo->unread_marker may be nonzero if the entropy decoder
1107
* has already read a marker from the data source. Under normal conditions
1108
* cinfo->unread_marker will be reset to 0 before returning; if not reset,
1109
* it holds a marker which the decoder will be unable to read past.
1112
METHODDEF(wxjpeg_boolean)
1113
read_restart_marker (j_decompress_ptr cinfo)
1115
/* Obtain a marker unless we already did. */
1116
/* Note that next_marker will complain if it skips any data. */
1117
if (cinfo->unread_marker == 0) {
1118
if (! next_marker(cinfo))
1122
if (cinfo->unread_marker ==
1123
((int) M_RST0 + cinfo->marker->next_restart_num)) {
1124
/* Normal case --- swallow the marker and let entropy decoder continue */
1125
TRACEMS1(cinfo, 3, JTRC_RST, cinfo->marker->next_restart_num);
1126
cinfo->unread_marker = 0;
1128
/* Uh-oh, the restart markers have been messed up. */
1129
/* Let the data source manager determine how to resync. */
1130
if (! (*cinfo->src->resync_to_restart) (cinfo,
1131
cinfo->marker->next_restart_num))
1135
/* Update next-restart state */
1136
cinfo->marker->next_restart_num = (cinfo->marker->next_restart_num + 1) & 7;
1143
* This is the default resync_to_restart method for data source managers
1144
* to use if they don't have any better approach. Some data source managers
1145
* may be able to back up, or may have additional knowledge about the data
1146
* which permits a more intelligent recovery strategy; such managers would
1147
* presumably supply their own resync method.
1149
* read_restart_marker calls resync_to_restart if it finds a marker other than
1150
* the restart marker it was expecting. (This code is *not* used unless
1151
* a nonzero restart interval has been declared.) cinfo->unread_marker is
1152
* the marker code actually found (might be anything, except 0 or FF).
1153
* The desired restart marker number (0..7) is passed as a parameter.
1154
* This routine is supposed to apply whatever error recovery strategy seems
1155
* appropriate in order to position the input stream to the next data segment.
1156
* Note that cinfo->unread_marker is treated as a marker appearing before
1157
* the current data-source input point; usually it should be reset to zero
1159
* Returns FALSE if suspension is required.
1161
* This implementation is substantially constrained by wanting to treat the
1162
* input as a data stream; this means we can't back up. Therefore, we have
1163
* only the following actions to work with:
1164
* 1. Simply discard the marker and let the entropy decoder resume at next
1166
* 2. Read forward until we find another marker, discarding intervening
1167
* data. (In theory we could look ahead within the current bufferload,
1168
* without having to discard data if we don't find the desired marker.
1169
* This idea is not implemented here, in part because it makes behavior
1170
* dependent on buffer size and chance buffer-boundary positions.)
1171
* 3. Leave the marker unread (by failing to zero cinfo->unread_marker).
1172
* This will cause the entropy decoder to process an empty data segment,
1173
* inserting dummy zeroes, and then we will reprocess the marker.
1175
* #2 is appropriate if we think the desired marker lies ahead, while #3 is
1176
* appropriate if the found marker is a future restart marker (indicating
1177
* that we have missed the desired restart marker, probably because it got
1179
* We apply #2 or #3 if the found marker is a restart marker no more than
1180
* two counts behind or ahead of the expected one. We also apply #2 if the
1181
* found marker is not a legal JPEG marker code (it's certainly bogus data).
1182
* If the found marker is a restart marker more than 2 counts away, we do #1
1183
* (too much risk that the marker is erroneous; with luck we will be able to
1184
* resync at some future point).
1185
* For any valid non-restart JPEG marker, we apply #3. This keeps us from
1186
* overrunning the end of a scan. An implementation limited to single-scan
1187
* files might find it better to apply #2 for markers other than EOI, since
1188
* any other marker would have to be bogus data in that case.
1191
GLOBAL(wxjpeg_boolean)
1192
jpeg_resync_to_restart (j_decompress_ptr cinfo, int desired)
1194
int marker = cinfo->unread_marker;
1197
/* Always put up a warning. */
1198
WARNMS2(cinfo, JWRN_MUST_RESYNC, marker, desired);
1200
/* Outer loop handles repeated decision after scanning forward. */
1202
if (marker < (int) M_SOF0)
1203
action = 2; /* invalid marker */
1204
else if (marker < (int) M_RST0 || marker > (int) M_RST7)
1205
action = 3; /* valid non-restart marker */
1207
if (marker == ((int) M_RST0 + ((desired+1) & 7)) ||
1208
marker == ((int) M_RST0 + ((desired+2) & 7)))
1209
action = 3; /* one of the next two expected restarts */
1210
else if (marker == ((int) M_RST0 + ((desired-1) & 7)) ||
1211
marker == ((int) M_RST0 + ((desired-2) & 7)))
1212
action = 2; /* a prior restart, so advance */
1214
action = 1; /* desired restart or too far away */
1216
TRACEMS2(cinfo, 4, JTRC_RECOVERY_ACTION, marker, action);
1219
/* Discard marker and let entropy decoder resume processing. */
1220
cinfo->unread_marker = 0;
1223
/* Scan to the next marker, and repeat the decision loop. */
1224
if (! next_marker(cinfo))
1226
marker = cinfo->unread_marker;
1229
/* Return without advancing past this marker. */
1230
/* Entropy decoder will be forced to process an empty segment. */
1238
* Reset marker processing state to begin a fresh datastream.
1242
reset_marker_reader (j_decompress_ptr cinfo)
1244
my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1246
cinfo->comp_info = NULL; /* until allocated by get_sof */
1247
cinfo->input_scan_number = 0; /* no SOS seen yet */
1248
cinfo->unread_marker = 0; /* no pending marker */
1249
marker->pub.saw_SOI = FALSE; /* set internal state too */
1250
marker->pub.saw_SOF = FALSE;
1251
marker->pub.discarded_bytes = 0;
1252
marker->cur_marker = NULL;
1257
* Initialize the marker reader module.
1258
* This is called only once, when the decompression object is created.
1262
jinit_marker_reader (j_decompress_ptr cinfo)
1264
my_marker_ptr marker;
1267
/* Create subobject in permanent pool */
1268
marker = (my_marker_ptr)
1269
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
1270
SIZEOF(my_marker_reader));
1271
cinfo->marker = (struct jpeg_marker_reader *) marker;
1272
/* Initialize public method pointers */
1273
marker->pub.reset_marker_reader = reset_marker_reader;
1274
marker->pub.read_markers = read_markers;
1275
marker->pub.read_restart_marker = read_restart_marker;
1276
/* Initialize COM/APPn processing.
1277
* By default, we examine and then discard APP0 and APP14,
1278
* but simply discard COM and all other APPn.
1280
marker->process_COM = skip_variable;
1281
marker->length_limit_COM = 0;
1282
for (i = 0; i < 16; i++) {
1283
marker->process_APPn[i] = skip_variable;
1284
marker->length_limit_APPn[i] = 0;
1286
marker->process_APPn[0] = get_interesting_appn;
1287
marker->process_APPn[14] = get_interesting_appn;
1288
/* Reset marker processing state */
1289
reset_marker_reader(cinfo);
1294
* Control saving of COM and APPn markers into marker_list.
1297
#ifdef SAVE_MARKERS_SUPPORTED
1300
jpeg_save_markers (j_decompress_ptr cinfo, int marker_code,
1301
unsigned int length_limit)
1303
my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1305
jpeg_marker_parser_method processor;
1307
/* Length limit mustn't be larger than what we can allocate
1308
* (should only be a concern in a 16-bit environment).
1310
maxlength = cinfo->mem->max_alloc_chunk - SIZEOF(struct jpeg_marker_struct);
1311
if (((long) length_limit) > maxlength)
1312
length_limit = (unsigned int) maxlength;
1314
/* Choose processor routine to use.
1315
* APP0/APP14 have special requirements.
1318
processor = save_marker;
1319
/* If saving APP0/APP14, save at least enough for our internal use. */
1320
if (marker_code == (int) M_APP0 && length_limit < APP0_DATA_LEN)
1321
length_limit = APP0_DATA_LEN;
1322
else if (marker_code == (int) M_APP14 && length_limit < APP14_DATA_LEN)
1323
length_limit = APP14_DATA_LEN;
1325
processor = skip_variable;
1326
/* If discarding APP0/APP14, use our regular on-the-fly processor. */
1327
if (marker_code == (int) M_APP0 || marker_code == (int) M_APP14)
1328
processor = get_interesting_appn;
1331
if (marker_code == (int) M_COM) {
1332
marker->process_COM = processor;
1333
marker->length_limit_COM = length_limit;
1334
} else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15) {
1335
marker->process_APPn[marker_code - (int) M_APP0] = processor;
1336
marker->length_limit_APPn[marker_code - (int) M_APP0] = length_limit;
1338
ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
1341
#endif /* SAVE_MARKERS_SUPPORTED */
1345
* Install a special processing method for COM or APPn markers.
1349
jpeg_set_marker_processor (j_decompress_ptr cinfo, int marker_code,
1350
jpeg_marker_parser_method routine)
1352
my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1354
if (marker_code == (int) M_COM)
1355
marker->process_COM = routine;
1356
else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15)
1357
marker->process_APPn[marker_code - (int) M_APP0] = routine;
1359
ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
added
removed
src/jpeg/jdmarker.c
