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comparison: media/libjpeg/jdmarker.c

media/libjpeg/jdmarker.c

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1 /*
2 * jdmarker.c
3 *
4 * This file was part of the Independent JPEG Group's software:
5 * Copyright (C) 1991-1998, Thomas G. Lane.
6 * libjpeg-turbo Modifications:
7 * Copyright (C) 2012, D. R. Commander.
8 * For conditions of distribution and use, see the accompanying README file.
9 *
10 * This file contains routines to decode JPEG datastream markers.
11 * Most of the complexity arises from our desire to support input
12 * suspension: if not all of the data for a marker is available,
13 * we must exit back to the application. On resumption, we reprocess
14 * the marker.
15 */
16
17 #define JPEG_INTERNALS
18 #include "jinclude.h"
19 #include "jpeglib.h"
20
21
22 typedef enum { /* JPEG marker codes */
23 M_SOF0 = 0xc0,
24 M_SOF1 = 0xc1,
25 M_SOF2 = 0xc2,
26 M_SOF3 = 0xc3,
27
28 M_SOF5 = 0xc5,
29 M_SOF6 = 0xc6,
30 M_SOF7 = 0xc7,
31
32 M_JPG = 0xc8,
33 M_SOF9 = 0xc9,
34 M_SOF10 = 0xca,
35 M_SOF11 = 0xcb,
36
37 M_SOF13 = 0xcd,
38 M_SOF14 = 0xce,
39 M_SOF15 = 0xcf,
40
41 M_DHT = 0xc4,
42
43 M_DAC = 0xcc,
44
45 M_RST0 = 0xd0,
46 M_RST1 = 0xd1,
47 M_RST2 = 0xd2,
48 M_RST3 = 0xd3,
49 M_RST4 = 0xd4,
50 M_RST5 = 0xd5,
51 M_RST6 = 0xd6,
52 M_RST7 = 0xd7,
53
54 M_SOI = 0xd8,
55 M_EOI = 0xd9,
56 M_SOS = 0xda,
57 M_DQT = 0xdb,
58 M_DNL = 0xdc,
59 M_DRI = 0xdd,
60 M_DHP = 0xde,
61 M_EXP = 0xdf,
62
63 M_APP0 = 0xe0,
64 M_APP1 = 0xe1,
65 M_APP2 = 0xe2,
66 M_APP3 = 0xe3,
67 M_APP4 = 0xe4,
68 M_APP5 = 0xe5,
69 M_APP6 = 0xe6,
70 M_APP7 = 0xe7,
71 M_APP8 = 0xe8,
72 M_APP9 = 0xe9,
73 M_APP10 = 0xea,
74 M_APP11 = 0xeb,
75 M_APP12 = 0xec,
76 M_APP13 = 0xed,
77 M_APP14 = 0xee,
78 M_APP15 = 0xef,
79
80 M_JPG0 = 0xf0,
81 M_JPG13 = 0xfd,
82 M_COM = 0xfe,
83
84 M_TEM = 0x01,
85
86 M_ERROR = 0x100
87 } JPEG_MARKER;
88
89
90 /* Private state */
91
92 typedef struct {
93 struct jpeg_marker_reader pub; /* public fields */
94
95 /* Application-overridable marker processing methods */
96 jpeg_marker_parser_method process_COM;
97 jpeg_marker_parser_method process_APPn[16];
98
99 /* Limit on marker data length to save for each marker type */
100 unsigned int length_limit_COM;
101 unsigned int length_limit_APPn[16];
102
103 /* Status of COM/APPn marker saving */
104 jpeg_saved_marker_ptr cur_marker; /* NULL if not processing a marker */
105 unsigned int bytes_read; /* data bytes read so far in marker */
106 /* Note: cur_marker is not linked into marker_list until it's all read. */
107 } my_marker_reader;
108
109 typedef my_marker_reader * my_marker_ptr;
110
111
112 /*
113 * Macros for fetching data from the data source module.
114 *
115 * At all times, cinfo->src->next_input_byte and ->bytes_in_buffer reflect
116 * the current restart point; we update them only when we have reached a
117 * suitable place to restart if a suspension occurs.
118 */
119
120 /* Declare and initialize local copies of input pointer/count */
121 #define INPUT_VARS(cinfo) \
122 struct jpeg_source_mgr * datasrc = (cinfo)->src; \
123 const JOCTET * next_input_byte = datasrc->next_input_byte; \
124 size_t bytes_in_buffer = datasrc->bytes_in_buffer
125
126 /* Unload the local copies --- do this only at a restart boundary */
127 #define INPUT_SYNC(cinfo) \
128 ( datasrc->next_input_byte = next_input_byte, \
129 datasrc->bytes_in_buffer = bytes_in_buffer )
130
131 /* Reload the local copies --- used only in MAKE_BYTE_AVAIL */
132 #define INPUT_RELOAD(cinfo) \
133 ( next_input_byte = datasrc->next_input_byte, \
134 bytes_in_buffer = datasrc->bytes_in_buffer )
135
136 /* Internal macro for INPUT_BYTE and INPUT_2BYTES: make a byte available.
137 * Note we do *not* do INPUT_SYNC before calling fill_input_buffer,
138 * but we must reload the local copies after a successful fill.
139 */
140 #define MAKE_BYTE_AVAIL(cinfo,action) \
141 if (bytes_in_buffer == 0) { \
142 if (! (*datasrc->fill_input_buffer) (cinfo)) \
143 { action; } \
144 INPUT_RELOAD(cinfo); \
145 }
146
147 /* Read a byte into variable V.
148 * If must suspend, take the specified action (typically "return FALSE").
149 */
150 #define INPUT_BYTE(cinfo,V,action) \
151 MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \
152 bytes_in_buffer--; \
153 V = GETJOCTET(*next_input_byte++); )
154
155 /* As above, but read two bytes interpreted as an unsigned 16-bit integer.
156 * V should be declared unsigned int or perhaps INT32.
157 */
158 #define INPUT_2BYTES(cinfo,V,action) \
159 MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \
160 bytes_in_buffer--; \
161 V = ((unsigned int) GETJOCTET(*next_input_byte++)) << 8; \
162 MAKE_BYTE_AVAIL(cinfo,action); \
163 bytes_in_buffer--; \
164 V += GETJOCTET(*next_input_byte++); )
165
166
167 /*
168 * Routines to process JPEG markers.
169 *
170 * Entry condition: JPEG marker itself has been read and its code saved
171 * in cinfo->unread_marker; input restart point is just after the marker.
172 *
173 * Exit: if return TRUE, have read and processed any parameters, and have
174 * updated the restart point to point after the parameters.
175 * If return FALSE, was forced to suspend before reaching end of
176 * marker parameters; restart point has not been moved. Same routine
177 * will be called again after application supplies more input data.
178 *
179 * This approach to suspension assumes that all of a marker's parameters
180 * can fit into a single input bufferload. This should hold for "normal"
181 * markers. Some COM/APPn markers might have large parameter segments
182 * that might not fit. If we are simply dropping such a marker, we use
183 * skip_input_data to get past it, and thereby put the problem on the
184 * source manager's shoulders. If we are saving the marker's contents
185 * into memory, we use a slightly different convention: when forced to
186 * suspend, the marker processor updates the restart point to the end of
187 * what it's consumed (ie, the end of the buffer) before returning FALSE.
188 * On resumption, cinfo->unread_marker still contains the marker code,
189 * but the data source will point to the next chunk of marker data.
190 * The marker processor must retain internal state to deal with this.
191 *
192 * Note that we don't bother to avoid duplicate trace messages if a
193 * suspension occurs within marker parameters. Other side effects
194 * require more care.
195 */
196
197
198 LOCAL(boolean)
199 get_soi (j_decompress_ptr cinfo)
200 /* Process an SOI marker */
201 {
202 int i;
203
204 TRACEMS(cinfo, 1, JTRC_SOI);
205
206 if (cinfo->marker->saw_SOI)
207 ERREXIT(cinfo, JERR_SOI_DUPLICATE);
208
209 /* Reset all parameters that are defined to be reset by SOI */
210
211 for (i = 0; i < NUM_ARITH_TBLS; i++) {
212 cinfo->arith_dc_L[i] = 0;
213 cinfo->arith_dc_U[i] = 1;
214 cinfo->arith_ac_K[i] = 5;
215 }
216 cinfo->restart_interval = 0;
217
218 /* Set initial assumptions for colorspace etc */
219
220 cinfo->jpeg_color_space = JCS_UNKNOWN;
221 cinfo->CCIR601_sampling = FALSE; /* Assume non-CCIR sampling??? */
222
223 cinfo->saw_JFIF_marker = FALSE;
224 cinfo->JFIF_major_version = 1; /* set default JFIF APP0 values */
225 cinfo->JFIF_minor_version = 1;
226 cinfo->density_unit = 0;
227 cinfo->X_density = 1;
228 cinfo->Y_density = 1;
229 cinfo->saw_Adobe_marker = FALSE;
230 cinfo->Adobe_transform = 0;
231
232 cinfo->marker->saw_SOI = TRUE;
233
234 return TRUE;
235 }
236
237
238 LOCAL(boolean)
239 get_sof (j_decompress_ptr cinfo, boolean is_prog, boolean is_arith)
240 /* Process a SOFn marker */
241 {
242 INT32 length;
243 int c, ci;
244 jpeg_component_info * compptr;
245 INPUT_VARS(cinfo);
246
247 cinfo->progressive_mode = is_prog;
248 cinfo->arith_code = is_arith;
249
250 INPUT_2BYTES(cinfo, length, return FALSE);
251
252 INPUT_BYTE(cinfo, cinfo->data_precision, return FALSE);
253 INPUT_2BYTES(cinfo, cinfo->image_height, return FALSE);
254 INPUT_2BYTES(cinfo, cinfo->image_width, return FALSE);
255 INPUT_BYTE(cinfo, cinfo->num_components, return FALSE);
256
257 length -= 8;
258
259 TRACEMS4(cinfo, 1, JTRC_SOF, cinfo->unread_marker,
260 (int) cinfo->image_width, (int) cinfo->image_height,
261 cinfo->num_components);
262
263 if (cinfo->marker->saw_SOF)
264 ERREXIT(cinfo, JERR_SOF_DUPLICATE);
265
266 /* We don't support files in which the image height is initially specified */
267 /* as 0 and is later redefined by DNL. As long as we have to check that, */
268 /* might as well have a general sanity check. */
269 if (cinfo->image_height <= 0 || cinfo->image_width <= 0
270 || cinfo->num_components <= 0)
271 ERREXIT(cinfo, JERR_EMPTY_IMAGE);
272
273 if (length != (cinfo->num_components * 3))
274 ERREXIT(cinfo, JERR_BAD_LENGTH);
275
276 if (cinfo->comp_info == NULL) /* do only once, even if suspend */
277 cinfo->comp_info = (jpeg_component_info *) (*cinfo->mem->alloc_small)
278 ((j_common_ptr) cinfo, JPOOL_IMAGE,
279 cinfo->num_components * SIZEOF(jpeg_component_info));
280
281 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
282 ci++, compptr++) {
283 compptr->component_index = ci;
284 INPUT_BYTE(cinfo, compptr->component_id, return FALSE);
285 INPUT_BYTE(cinfo, c, return FALSE);
286 compptr->h_samp_factor = (c >> 4) & 15;
287 compptr->v_samp_factor = (c ) & 15;
288 INPUT_BYTE(cinfo, compptr->quant_tbl_no, return FALSE);
289
290 TRACEMS4(cinfo, 1, JTRC_SOF_COMPONENT,
291 compptr->component_id, compptr->h_samp_factor,
292 compptr->v_samp_factor, compptr->quant_tbl_no);
293 }
294
295 cinfo->marker->saw_SOF = TRUE;
296
297 INPUT_SYNC(cinfo);
298 return TRUE;
299 }
300
301
302 LOCAL(boolean)
303 get_sos (j_decompress_ptr cinfo)
304 /* Process a SOS marker */
305 {
306 INT32 length;
307 int i, ci, n, c, cc, pi;
308 jpeg_component_info * compptr;
309 INPUT_VARS(cinfo);
310
311 if (! cinfo->marker->saw_SOF)
312 ERREXIT(cinfo, JERR_SOS_NO_SOF);
313
314 INPUT_2BYTES(cinfo, length, return FALSE);
315
316 INPUT_BYTE(cinfo, n, return FALSE); /* Number of components */
317
318 TRACEMS1(cinfo, 1, JTRC_SOS, n);
319
320 if (length != (n * 2 + 6) || n < 1 || n > MAX_COMPS_IN_SCAN)
321 ERREXIT(cinfo, JERR_BAD_LENGTH);
322
323 cinfo->comps_in_scan = n;
324
325 /* Collect the component-spec parameters */
326
327 for (i = 0; i < MAX_COMPS_IN_SCAN; i++)
328 cinfo->cur_comp_info[i] = NULL;
329
330 for (i = 0; i < n; i++) {
331 INPUT_BYTE(cinfo, cc, return FALSE);
332 INPUT_BYTE(cinfo, c, return FALSE);
333
334 for (ci = 0, compptr = cinfo->comp_info;
335 ci < cinfo->num_components && ci < MAX_COMPS_IN_SCAN;
336 ci++, compptr++) {
337 if (cc == compptr->component_id && !cinfo->cur_comp_info[ci])
338 goto id_found;
339 }
340
341 ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc);
342
343 id_found:
344
345 cinfo->cur_comp_info[i] = compptr;
346 compptr->dc_tbl_no = (c >> 4) & 15;
347 compptr->ac_tbl_no = (c ) & 15;
348
349 TRACEMS3(cinfo, 1, JTRC_SOS_COMPONENT, cc,
350 compptr->dc_tbl_no, compptr->ac_tbl_no);
351
352 /* This CSi (cc) should differ from the previous CSi */
353 for (pi = 0; pi < i; pi++) {
354 if (cinfo->cur_comp_info[pi] == compptr) {
355 ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc);
356 }
357 }
358 }
359
360 /* Collect the additional scan parameters Ss, Se, Ah/Al. */
361 INPUT_BYTE(cinfo, c, return FALSE);
362 cinfo->Ss = c;
363 INPUT_BYTE(cinfo, c, return FALSE);
364 cinfo->Se = c;
365 INPUT_BYTE(cinfo, c, return FALSE);
366 cinfo->Ah = (c >> 4) & 15;
367 cinfo->Al = (c ) & 15;
368
369 TRACEMS4(cinfo, 1, JTRC_SOS_PARAMS, cinfo->Ss, cinfo->Se,
370 cinfo->Ah, cinfo->Al);
371
372 /* Prepare to scan data & restart markers */
373 cinfo->marker->next_restart_num = 0;
374
375 /* Count another SOS marker */
376 cinfo->input_scan_number++;
377
378 INPUT_SYNC(cinfo);
379 return TRUE;
380 }
381
382
383 #ifdef D_ARITH_CODING_SUPPORTED
384
385 LOCAL(boolean)
386 get_dac (j_decompress_ptr cinfo)
387 /* Process a DAC marker */
388 {
389 INT32 length;
390 int index, val;
391 INPUT_VARS(cinfo);
392
393 INPUT_2BYTES(cinfo, length, return FALSE);
394 length -= 2;
395
396 while (length > 0) {
397 INPUT_BYTE(cinfo, index, return FALSE);
398 INPUT_BYTE(cinfo, val, return FALSE);
399
400 length -= 2;
401
402 TRACEMS2(cinfo, 1, JTRC_DAC, index, val);
403
404 if (index < 0 || index >= (2*NUM_ARITH_TBLS))
405 ERREXIT1(cinfo, JERR_DAC_INDEX, index);
406
407 if (index >= NUM_ARITH_TBLS) { /* define AC table */
408 cinfo->arith_ac_K[index-NUM_ARITH_TBLS] = (UINT8) val;
409 } else { /* define DC table */
410 cinfo->arith_dc_L[index] = (UINT8) (val & 0x0F);
411 cinfo->arith_dc_U[index] = (UINT8) (val >> 4);
412 if (cinfo->arith_dc_L[index] > cinfo->arith_dc_U[index])
413 ERREXIT1(cinfo, JERR_DAC_VALUE, val);
414 }
415 }
416
417 if (length != 0)
418 ERREXIT(cinfo, JERR_BAD_LENGTH);
419
420 INPUT_SYNC(cinfo);
421 return TRUE;
422 }
423
424 #else /* ! D_ARITH_CODING_SUPPORTED */
425
426 #define get_dac(cinfo) skip_variable(cinfo)
427
428 #endif /* D_ARITH_CODING_SUPPORTED */
429
430
431 LOCAL(boolean)
432 get_dht (j_decompress_ptr cinfo)
433 /* Process a DHT marker */
434 {
435 INT32 length;
436 UINT8 bits[17];
437 UINT8 huffval[256];
438 int i, index, count;
439 JHUFF_TBL **htblptr;
440 INPUT_VARS(cinfo);
441
442 INPUT_2BYTES(cinfo, length, return FALSE);
443 length -= 2;
444
445 while (length > 16) {
446 INPUT_BYTE(cinfo, index, return FALSE);
447
448 TRACEMS1(cinfo, 1, JTRC_DHT, index);
449
450 bits[0] = 0;
451 count = 0;
452 for (i = 1; i <= 16; i++) {
453 INPUT_BYTE(cinfo, bits[i], return FALSE);
454 count += bits[i];
455 }
456
457 length -= 1 + 16;
458
459 TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
460 bits[1], bits[2], bits[3], bits[4],
461 bits[5], bits[6], bits[7], bits[8]);
462 TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
463 bits[9], bits[10], bits[11], bits[12],
464 bits[13], bits[14], bits[15], bits[16]);
465
466 /* Here we just do minimal validation of the counts to avoid walking
467 * off the end of our table space. jdhuff.c will check more carefully.
468 */
469 if (count > 256 || ((INT32) count) > length)
470 ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
471
472 for (i = 0; i < count; i++)
473 INPUT_BYTE(cinfo, huffval[i], return FALSE);
474
475 MEMZERO(&huffval[count], (256 - count) * SIZEOF(UINT8));
476
477 length -= count;
478
479 if (index & 0x10) { /* AC table definition */
480 index -= 0x10;
481 if (index < 0 || index >= NUM_HUFF_TBLS)
482 ERREXIT1(cinfo, JERR_DHT_INDEX, index);
483 htblptr = &cinfo->ac_huff_tbl_ptrs[index];
484 } else { /* DC table definition */
485 if (index < 0 || index >= NUM_HUFF_TBLS)
486 ERREXIT1(cinfo, JERR_DHT_INDEX, index);
487 htblptr = &cinfo->dc_huff_tbl_ptrs[index];
488 }
489
490 if (*htblptr == NULL)
491 *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
492
493 MEMCOPY((*htblptr)->bits, bits, SIZEOF((*htblptr)->bits));
494 MEMCOPY((*htblptr)->huffval, huffval, SIZEOF((*htblptr)->huffval));
495 }
496
497 if (length != 0)
498 ERREXIT(cinfo, JERR_BAD_LENGTH);
499
500 INPUT_SYNC(cinfo);
501 return TRUE;
502 }
503
504
505 LOCAL(boolean)
506 get_dqt (j_decompress_ptr cinfo)
507 /* Process a DQT marker */
508 {
509 INT32 length;
510 int n, i, prec;
511 unsigned int tmp;
512 JQUANT_TBL *quant_ptr;
513 INPUT_VARS(cinfo);
514
515 INPUT_2BYTES(cinfo, length, return FALSE);
516 length -= 2;
517
518 while (length > 0) {
519 INPUT_BYTE(cinfo, n, return FALSE);
520 prec = n >> 4;
521 n &= 0x0F;
522
523 TRACEMS2(cinfo, 1, JTRC_DQT, n, prec);
524
525 if (n >= NUM_QUANT_TBLS)
526 ERREXIT1(cinfo, JERR_DQT_INDEX, n);
527
528 if (cinfo->quant_tbl_ptrs[n] == NULL)
529 cinfo->quant_tbl_ptrs[n] = jpeg_alloc_quant_table((j_common_ptr) cinfo);
530 quant_ptr = cinfo->quant_tbl_ptrs[n];
531
532 for (i = 0; i < DCTSIZE2; i++) {
533 if (prec)
534 INPUT_2BYTES(cinfo, tmp, return FALSE);
535 else
536 INPUT_BYTE(cinfo, tmp, return FALSE);
537 /* We convert the zigzag-order table to natural array order. */
538 quant_ptr->quantval[jpeg_natural_order[i]] = (UINT16) tmp;
539 }
540
541 if (cinfo->err->trace_level >= 2) {
542 for (i = 0; i < DCTSIZE2; i += 8) {
543 TRACEMS8(cinfo, 2, JTRC_QUANTVALS,
544 quant_ptr->quantval[i], quant_ptr->quantval[i+1],
545 quant_ptr->quantval[i+2], quant_ptr->quantval[i+3],
546 quant_ptr->quantval[i+4], quant_ptr->quantval[i+5],
547 quant_ptr->quantval[i+6], quant_ptr->quantval[i+7]);
548 }
549 }
550
551 length -= DCTSIZE2+1;
552 if (prec) length -= DCTSIZE2;
553 }
554
555 if (length != 0)
556 ERREXIT(cinfo, JERR_BAD_LENGTH);
557
558 INPUT_SYNC(cinfo);
559 return TRUE;
560 }
561
562
563 LOCAL(boolean)
564 get_dri (j_decompress_ptr cinfo)
565 /* Process a DRI marker */
566 {
567 INT32 length;
568 unsigned int tmp;
569 INPUT_VARS(cinfo);
570
571 INPUT_2BYTES(cinfo, length, return FALSE);
572
573 if (length != 4)
574 ERREXIT(cinfo, JERR_BAD_LENGTH);
575
576 INPUT_2BYTES(cinfo, tmp, return FALSE);
577
578 TRACEMS1(cinfo, 1, JTRC_DRI, tmp);
579
580 cinfo->restart_interval = tmp;
581
582 INPUT_SYNC(cinfo);
583 return TRUE;
584 }
585
586
587 /*
588 * Routines for processing APPn and COM markers.
589 * These are either saved in memory or discarded, per application request.
590 * APP0 and APP14 are specially checked to see if they are
591 * JFIF and Adobe markers, respectively.
592 */
593
594 #define APP0_DATA_LEN 14 /* Length of interesting data in APP0 */
595 #define APP14_DATA_LEN 12 /* Length of interesting data in APP14 */
596 #define APPN_DATA_LEN 14 /* Must be the largest of the above!! */
597
598
599 LOCAL(void)
600 examine_app0 (j_decompress_ptr cinfo, JOCTET FAR * data,
601 unsigned int datalen, INT32 remaining)
602 /* Examine first few bytes from an APP0.
603 * Take appropriate action if it is a JFIF marker.
604 * datalen is # of bytes at data[], remaining is length of rest of marker data.
605 */
606 {
607 INT32 totallen = (INT32) datalen + remaining;
608
609 if (datalen >= APP0_DATA_LEN &&
610 GETJOCTET(data[0]) == 0x4A &&
611 GETJOCTET(data[1]) == 0x46 &&
612 GETJOCTET(data[2]) == 0x49 &&
613 GETJOCTET(data[3]) == 0x46 &&
614 GETJOCTET(data[4]) == 0) {
615 /* Found JFIF APP0 marker: save info */
616 cinfo->saw_JFIF_marker = TRUE;
617 cinfo->JFIF_major_version = GETJOCTET(data[5]);
618 cinfo->JFIF_minor_version = GETJOCTET(data[6]);
619 cinfo->density_unit = GETJOCTET(data[7]);
620 cinfo->X_density = (GETJOCTET(data[8]) << 8) + GETJOCTET(data[9]);
621 cinfo->Y_density = (GETJOCTET(data[10]) << 8) + GETJOCTET(data[11]);
622 /* Check version.
623 * Major version must be 1, anything else signals an incompatible change.
624 * (We used to treat this as an error, but now it's a nonfatal warning,
625 * because some bozo at Hijaak couldn't read the spec.)
626 * Minor version should be 0..2, but process anyway if newer.
627 */
628 if (cinfo->JFIF_major_version != 1)
629 WARNMS2(cinfo, JWRN_JFIF_MAJOR,
630 cinfo->JFIF_major_version, cinfo->JFIF_minor_version);
631 /* Generate trace messages */
632 TRACEMS5(cinfo, 1, JTRC_JFIF,
633 cinfo->JFIF_major_version, cinfo->JFIF_minor_version,
634 cinfo->X_density, cinfo->Y_density, cinfo->density_unit);
635 /* Validate thumbnail dimensions and issue appropriate messages */
636 if (GETJOCTET(data[12]) | GETJOCTET(data[13]))
637 TRACEMS2(cinfo, 1, JTRC_JFIF_THUMBNAIL,
638 GETJOCTET(data[12]), GETJOCTET(data[13]));
639 totallen -= APP0_DATA_LEN;
640 if (totallen !=
641 ((INT32)GETJOCTET(data[12]) * (INT32)GETJOCTET(data[13]) * (INT32) 3))
642 TRACEMS1(cinfo, 1, JTRC_JFIF_BADTHUMBNAILSIZE, (int) totallen);
643 } else if (datalen >= 6 &&
644 GETJOCTET(data[0]) == 0x4A &&
645 GETJOCTET(data[1]) == 0x46 &&
646 GETJOCTET(data[2]) == 0x58 &&
647 GETJOCTET(data[3]) == 0x58 &&
648 GETJOCTET(data[4]) == 0) {
649 /* Found JFIF "JFXX" extension APP0 marker */
650 /* The library doesn't actually do anything with these,
651 * but we try to produce a helpful trace message.
652 */
653 switch (GETJOCTET(data[5])) {
654 case 0x10:
655 TRACEMS1(cinfo, 1, JTRC_THUMB_JPEG, (int) totallen);
656 break;
657 case 0x11:
658 TRACEMS1(cinfo, 1, JTRC_THUMB_PALETTE, (int) totallen);
659 break;
660 case 0x13:
661 TRACEMS1(cinfo, 1, JTRC_THUMB_RGB, (int) totallen);
662 break;
663 default:
664 TRACEMS2(cinfo, 1, JTRC_JFIF_EXTENSION,
665 GETJOCTET(data[5]), (int) totallen);
666 break;
667 }
668 } else {
669 /* Start of APP0 does not match "JFIF" or "JFXX", or too short */
670 TRACEMS1(cinfo, 1, JTRC_APP0, (int) totallen);
671 }
672 }
673
674
675 LOCAL(void)
676 examine_app14 (j_decompress_ptr cinfo, JOCTET FAR * data,
677 unsigned int datalen, INT32 remaining)
678 /* Examine first few bytes from an APP14.
679 * Take appropriate action if it is an Adobe marker.
680 * datalen is # of bytes at data[], remaining is length of rest of marker data.
681 */
682 {
683 unsigned int version, flags0, flags1, transform;
684
685 if (datalen >= APP14_DATA_LEN &&
686 GETJOCTET(data[0]) == 0x41 &&
687 GETJOCTET(data[1]) == 0x64 &&
688 GETJOCTET(data[2]) == 0x6F &&
689 GETJOCTET(data[3]) == 0x62 &&
690 GETJOCTET(data[4]) == 0x65) {
691 /* Found Adobe APP14 marker */
692 version = (GETJOCTET(data[5]) << 8) + GETJOCTET(data[6]);
693 flags0 = (GETJOCTET(data[7]) << 8) + GETJOCTET(data[8]);
694 flags1 = (GETJOCTET(data[9]) << 8) + GETJOCTET(data[10]);
695 transform = GETJOCTET(data[11]);
696 TRACEMS4(cinfo, 1, JTRC_ADOBE, version, flags0, flags1, transform);
697 cinfo->saw_Adobe_marker = TRUE;
698 cinfo->Adobe_transform = (UINT8) transform;
699 } else {
700 /* Start of APP14 does not match "Adobe", or too short */
701 TRACEMS1(cinfo, 1, JTRC_APP14, (int) (datalen + remaining));
702 }
703 }
704
705
706 METHODDEF(boolean)
707 get_interesting_appn (j_decompress_ptr cinfo)
708 /* Process an APP0 or APP14 marker without saving it */
709 {
710 INT32 length;
711 JOCTET b[APPN_DATA_LEN];
712 unsigned int i, numtoread;
713 INPUT_VARS(cinfo);
714
715 INPUT_2BYTES(cinfo, length, return FALSE);
716 length -= 2;
717
718 /* get the interesting part of the marker data */
719 if (length >= APPN_DATA_LEN)
720 numtoread = APPN_DATA_LEN;
721 else if (length > 0)
722 numtoread = (unsigned int) length;
723 else
724 numtoread = 0;
725 for (i = 0; i < numtoread; i++)
726 INPUT_BYTE(cinfo, b[i], return FALSE);
727 length -= numtoread;
728
729 /* process it */
730 switch (cinfo->unread_marker) {
731 case M_APP0:
732 examine_app0(cinfo, (JOCTET FAR *) b, numtoread, length);
733 break;
734 case M_APP14:
735 examine_app14(cinfo, (JOCTET FAR *) b, numtoread, length);
736 break;
737 default:
738 /* can't get here unless jpeg_save_markers chooses wrong processor */
739 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
740 break;
741 }
742
743 /* skip any remaining data -- could be lots */
744 INPUT_SYNC(cinfo);
745 if (length > 0)
746 (*cinfo->src->skip_input_data) (cinfo, (long) length);
747
748 return TRUE;
749 }
750
751
752 #ifdef SAVE_MARKERS_SUPPORTED
753
754 METHODDEF(boolean)
755 save_marker (j_decompress_ptr cinfo)
756 /* Save an APPn or COM marker into the marker list */
757 {
758 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
759 jpeg_saved_marker_ptr cur_marker = marker->cur_marker;
760 unsigned int bytes_read, data_length;
761 JOCTET FAR * data;
762 INT32 length = 0;
763 INPUT_VARS(cinfo);
764
765 if (cur_marker == NULL) {
766 /* begin reading a marker */
767 INPUT_2BYTES(cinfo, length, return FALSE);
768 length -= 2;
769 if (length >= 0) { /* watch out for bogus length word */
770 /* figure out how much we want to save */
771 unsigned int limit;
772 if (cinfo->unread_marker == (int) M_COM)
773 limit = marker->length_limit_COM;
774 else
775 limit = marker->length_limit_APPn[cinfo->unread_marker - (int) M_APP0];
776 if ((unsigned int) length < limit)
777 limit = (unsigned int) length;
778 /* allocate and initialize the marker item */
779 cur_marker = (jpeg_saved_marker_ptr)
780 (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
781 SIZEOF(struct jpeg_marker_struct) + limit);
782 cur_marker->next = NULL;
783 cur_marker->marker = (UINT8) cinfo->unread_marker;
784 cur_marker->original_length = (unsigned int) length;
785 cur_marker->data_length = limit;
786 /* data area is just beyond the jpeg_marker_struct */
787 data = cur_marker->data = (JOCTET FAR *) (cur_marker + 1);
788 marker->cur_marker = cur_marker;
789 marker->bytes_read = 0;
790 bytes_read = 0;
791 data_length = limit;
792 } else {
793 /* deal with bogus length word */
794 bytes_read = data_length = 0;
795 data = NULL;
796 }
797 } else {
798 /* resume reading a marker */
799 bytes_read = marker->bytes_read;
800 data_length = cur_marker->data_length;
801 data = cur_marker->data + bytes_read;
802 }
803
804 while (bytes_read < data_length) {
805 INPUT_SYNC(cinfo); /* move the restart point to here */
806 marker->bytes_read = bytes_read;
807 /* If there's not at least one byte in buffer, suspend */
808 MAKE_BYTE_AVAIL(cinfo, return FALSE);
809 /* Copy bytes with reasonable rapidity */
810 while (bytes_read < data_length && bytes_in_buffer > 0) {
811 *data++ = *next_input_byte++;
812 bytes_in_buffer--;
813 bytes_read++;
814 }
815 }
816
817 /* Done reading what we want to read */
818 if (cur_marker != NULL) { /* will be NULL if bogus length word */
819 /* Add new marker to end of list */
820 if (cinfo->marker_list == NULL) {
821 cinfo->marker_list = cur_marker;
822 } else {
823 jpeg_saved_marker_ptr prev = cinfo->marker_list;
824 while (prev->next != NULL)
825 prev = prev->next;
826 prev->next = cur_marker;
827 }
828 /* Reset pointer & calc remaining data length */
829 data = cur_marker->data;
830 length = cur_marker->original_length - data_length;
831 }
832 /* Reset to initial state for next marker */
833 marker->cur_marker = NULL;
834
835 /* Process the marker if interesting; else just make a generic trace msg */
836 switch (cinfo->unread_marker) {
837 case M_APP0:
838 examine_app0(cinfo, data, data_length, length);
839 break;
840 case M_APP14:
841 examine_app14(cinfo, data, data_length, length);
842 break;
843 default:
844 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker,
845 (int) (data_length + length));
846 break;
847 }
848
849 /* skip any remaining data -- could be lots */
850 INPUT_SYNC(cinfo); /* do before skip_input_data */
851 if (length > 0)
852 (*cinfo->src->skip_input_data) (cinfo, (long) length);
853
854 return TRUE;
855 }
856
857 #endif /* SAVE_MARKERS_SUPPORTED */
858
859
860 METHODDEF(boolean)
861 skip_variable (j_decompress_ptr cinfo)
862 /* Skip over an unknown or uninteresting variable-length marker */
863 {
864 INT32 length;
865 INPUT_VARS(cinfo);
866
867 INPUT_2BYTES(cinfo, length, return FALSE);
868 length -= 2;
869
870 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, (int) length);
871
872 INPUT_SYNC(cinfo); /* do before skip_input_data */
873 if (length > 0)
874 (*cinfo->src->skip_input_data) (cinfo, (long) length);
875
876 return TRUE;
877 }
878
879
880 /*
881 * Find the next JPEG marker, save it in cinfo->unread_marker.
882 * Returns FALSE if had to suspend before reaching a marker;
883 * in that case cinfo->unread_marker is unchanged.
884 *
885 * Note that the result might not be a valid marker code,
886 * but it will never be 0 or FF.
887 */
888
889 LOCAL(boolean)
890 next_marker (j_decompress_ptr cinfo)
891 {
892 int c;
893 INPUT_VARS(cinfo);
894
895 for (;;) {
896 INPUT_BYTE(cinfo, c, return FALSE);
897 /* Skip any non-FF bytes.
898 * This may look a bit inefficient, but it will not occur in a valid file.
899 * We sync after each discarded byte so that a suspending data source
900 * can discard the byte from its buffer.
901 */
902 while (c != 0xFF) {
903 cinfo->marker->discarded_bytes++;
904 INPUT_SYNC(cinfo);
905 INPUT_BYTE(cinfo, c, return FALSE);
906 }
907 /* This loop swallows any duplicate FF bytes. Extra FFs are legal as
908 * pad bytes, so don't count them in discarded_bytes. We assume there
909 * will not be so many consecutive FF bytes as to overflow a suspending
910 * data source's input buffer.
911 */
912 do {
913 INPUT_BYTE(cinfo, c, return FALSE);
914 } while (c == 0xFF);
915 if (c != 0)
916 break; /* found a valid marker, exit loop */
917 /* Reach here if we found a stuffed-zero data sequence (FF/00).
918 * Discard it and loop back to try again.
919 */
920 cinfo->marker->discarded_bytes += 2;
921 INPUT_SYNC(cinfo);
922 }
923
924 if (cinfo->marker->discarded_bytes != 0) {
925 WARNMS2(cinfo, JWRN_EXTRANEOUS_DATA, cinfo->marker->discarded_bytes, c);
926 cinfo->marker->discarded_bytes = 0;
927 }
928
929 cinfo->unread_marker = c;
930
931 INPUT_SYNC(cinfo);
932 return TRUE;
933 }
934
935
936 LOCAL(boolean)
937 first_marker (j_decompress_ptr cinfo)
938 /* Like next_marker, but used to obtain the initial SOI marker. */
939 /* For this marker, we do not allow preceding garbage or fill; otherwise,
940 * we might well scan an entire input file before realizing it ain't JPEG.
941 * If an application wants to process non-JFIF files, it must seek to the
942 * SOI before calling the JPEG library.
943 */
944 {
945 int c, c2;
946 INPUT_VARS(cinfo);
947
948 INPUT_BYTE(cinfo, c, return FALSE);
949 INPUT_BYTE(cinfo, c2, return FALSE);
950 if (c != 0xFF || c2 != (int) M_SOI)
951 ERREXIT2(cinfo, JERR_NO_SOI, c, c2);
952
953 cinfo->unread_marker = c2;
954
955 INPUT_SYNC(cinfo);
956 return TRUE;
957 }
958
959
960 /*
961 * Read markers until SOS or EOI.
962 *
963 * Returns same codes as are defined for jpeg_consume_input:
964 * JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
965 */
966
967 METHODDEF(int)
968 read_markers (j_decompress_ptr cinfo)
969 {
970 /* Outer loop repeats once for each marker. */
971 for (;;) {
972 /* Collect the marker proper, unless we already did. */
973 /* NB: first_marker() enforces the requirement that SOI appear first. */
974 if (cinfo->unread_marker == 0) {
975 if (! cinfo->marker->saw_SOI) {
976 if (! first_marker(cinfo))
977 return JPEG_SUSPENDED;
978 } else {
979 if (! next_marker(cinfo))
980 return JPEG_SUSPENDED;
981 }
982 }
983 /* At this point cinfo->unread_marker contains the marker code and the
984 * input point is just past the marker proper, but before any parameters.
985 * A suspension will cause us to return with this state still true.
986 */
987 switch (cinfo->unread_marker) {
988 case M_SOI:
989 if (! get_soi(cinfo))
990 return JPEG_SUSPENDED;
991 break;
992
993 case M_SOF0: /* Baseline */
994 case M_SOF1: /* Extended sequential, Huffman */
995 if (! get_sof(cinfo, FALSE, FALSE))
996 return JPEG_SUSPENDED;
997 break;
998
999 case M_SOF2: /* Progressive, Huffman */
1000 if (! get_sof(cinfo, TRUE, FALSE))
1001 return JPEG_SUSPENDED;
1002 break;
1003
1004 case M_SOF9: /* Extended sequential, arithmetic */
1005 if (! get_sof(cinfo, FALSE, TRUE))
1006 return JPEG_SUSPENDED;
1007 break;
1008
1009 case M_SOF10: /* Progressive, arithmetic */
1010 if (! get_sof(cinfo, TRUE, TRUE))
1011 return JPEG_SUSPENDED;
1012 break;
1013
1014 /* Currently unsupported SOFn types */
1015 case M_SOF3: /* Lossless, Huffman */
1016 case M_SOF5: /* Differential sequential, Huffman */
1017 case M_SOF6: /* Differential progressive, Huffman */
1018 case M_SOF7: /* Differential lossless, Huffman */
1019 case M_JPG: /* Reserved for JPEG extensions */
1020 case M_SOF11: /* Lossless, arithmetic */
1021 case M_SOF13: /* Differential sequential, arithmetic */
1022 case M_SOF14: /* Differential progressive, arithmetic */
1023 case M_SOF15: /* Differential lossless, arithmetic */
1024 ERREXIT1(cinfo, JERR_SOF_UNSUPPORTED, cinfo->unread_marker);
1025 break;
1026
1027 case M_SOS:
1028 if (! get_sos(cinfo))
1029 return JPEG_SUSPENDED;
1030 cinfo->unread_marker = 0; /* processed the marker */
1031 return JPEG_REACHED_SOS;
1032
1033 case M_EOI:
1034 TRACEMS(cinfo, 1, JTRC_EOI);
1035 cinfo->unread_marker = 0; /* processed the marker */
1036 return JPEG_REACHED_EOI;
1037
1038 case M_DAC:
1039 if (! get_dac(cinfo))
1040 return JPEG_SUSPENDED;
1041 break;
1042
1043 case M_DHT:
1044 if (! get_dht(cinfo))
1045 return JPEG_SUSPENDED;
1046 break;
1047
1048 case M_DQT:
1049 if (! get_dqt(cinfo))
1050 return JPEG_SUSPENDED;
1051 break;
1052
1053 case M_DRI:
1054 if (! get_dri(cinfo))
1055 return JPEG_SUSPENDED;
1056 break;
1057
1058 case M_APP0:
1059 case M_APP1:
1060 case M_APP2:
1061 case M_APP3:
1062 case M_APP4:
1063 case M_APP5:
1064 case M_APP6:
1065 case M_APP7:
1066 case M_APP8:
1067 case M_APP9:
1068 case M_APP10:
1069 case M_APP11:
1070 case M_APP12:
1071 case M_APP13:
1072 case M_APP14:
1073 case M_APP15:
1074 if (! (*((my_marker_ptr) cinfo->marker)->process_APPn[
1075 cinfo->unread_marker - (int) M_APP0]) (cinfo))
1076 return JPEG_SUSPENDED;
1077 break;
1078
1079 case M_COM:
1080 if (! (*((my_marker_ptr) cinfo->marker)->process_COM) (cinfo))
1081 return JPEG_SUSPENDED;
1082 break;
1083
1084 case M_RST0: /* these are all parameterless */
1085 case M_RST1:
1086 case M_RST2:
1087 case M_RST3:
1088 case M_RST4:
1089 case M_RST5:
1090 case M_RST6:
1091 case M_RST7:
1092 case M_TEM:
1093 TRACEMS1(cinfo, 1, JTRC_PARMLESS_MARKER, cinfo->unread_marker);
1094 break;
1095
1096 case M_DNL: /* Ignore DNL ... perhaps the wrong thing */
1097 if (! skip_variable(cinfo))
1098 return JPEG_SUSPENDED;
1099 break;
1100
1101 default: /* must be DHP, EXP, JPGn, or RESn */
1102 /* For now, we treat the reserved markers as fatal errors since they are
1103 * likely to be used to signal incompatible JPEG Part 3 extensions.
1104 * Once the JPEG 3 version-number marker is well defined, this code
1105 * ought to change!
1106 */
1107 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
1108 break;
1109 }
1110 /* Successfully processed marker, so reset state variable */
1111 cinfo->unread_marker = 0;
1112 } /* end loop */
1113 }
1114
1115
1116 /*
1117 * Read a restart marker, which is expected to appear next in the datastream;
1118 * if the marker is not there, take appropriate recovery action.
1119 * Returns FALSE if suspension is required.
1120 *
1121 * This is called by the entropy decoder after it has read an appropriate
1122 * number of MCUs. cinfo->unread_marker may be nonzero if the entropy decoder
1123 * has already read a marker from the data source. Under normal conditions
1124 * cinfo->unread_marker will be reset to 0 before returning; if not reset,
1125 * it holds a marker which the decoder will be unable to read past.
1126 */
1127
1128 METHODDEF(boolean)
1129 read_restart_marker (j_decompress_ptr cinfo)
1130 {
1131 /* Obtain a marker unless we already did. */
1132 /* Note that next_marker will complain if it skips any data. */
1133 if (cinfo->unread_marker == 0) {
1134 if (! next_marker(cinfo))
1135 return FALSE;
1136 }
1137
1138 if (cinfo->unread_marker ==
1139 ((int) M_RST0 + cinfo->marker->next_restart_num)) {
1140 /* Normal case --- swallow the marker and let entropy decoder continue */
1141 TRACEMS1(cinfo, 3, JTRC_RST, cinfo->marker->next_restart_num);
1142 cinfo->unread_marker = 0;
1143 } else {
1144 /* Uh-oh, the restart markers have been messed up. */
1145 /* Let the data source manager determine how to resync. */
1146 if (! (*cinfo->src->resync_to_restart) (cinfo,
1147 cinfo->marker->next_restart_num))
1148 return FALSE;
1149 }
1150
1151 /* Update next-restart state */
1152 cinfo->marker->next_restart_num = (cinfo->marker->next_restart_num + 1) & 7;
1153
1154 return TRUE;
1155 }
1156
1157
1158 /*
1159 * This is the default resync_to_restart method for data source managers
1160 * to use if they don't have any better approach. Some data source managers
1161 * may be able to back up, or may have additional knowledge about the data
1162 * which permits a more intelligent recovery strategy; such managers would
1163 * presumably supply their own resync method.
1164 *
1165 * read_restart_marker calls resync_to_restart if it finds a marker other than
1166 * the restart marker it was expecting. (This code is *not* used unless
1167 * a nonzero restart interval has been declared.) cinfo->unread_marker is
1168 * the marker code actually found (might be anything, except 0 or FF).
1169 * The desired restart marker number (0..7) is passed as a parameter.
1170 * This routine is supposed to apply whatever error recovery strategy seems
1171 * appropriate in order to position the input stream to the next data segment.
1172 * Note that cinfo->unread_marker is treated as a marker appearing before
1173 * the current data-source input point; usually it should be reset to zero
1174 * before returning.
1175 * Returns FALSE if suspension is required.
1176 *
1177 * This implementation is substantially constrained by wanting to treat the
1178 * input as a data stream; this means we can't back up. Therefore, we have
1179 * only the following actions to work with:
1180 * 1. Simply discard the marker and let the entropy decoder resume at next
1181 * byte of file.
1182 * 2. Read forward until we find another marker, discarding intervening
1183 * data. (In theory we could look ahead within the current bufferload,
1184 * without having to discard data if we don't find the desired marker.
1185 * This idea is not implemented here, in part because it makes behavior
1186 * dependent on buffer size and chance buffer-boundary positions.)
1187 * 3. Leave the marker unread (by failing to zero cinfo->unread_marker).
1188 * This will cause the entropy decoder to process an empty data segment,
1189 * inserting dummy zeroes, and then we will reprocess the marker.
1190 *
1191 * #2 is appropriate if we think the desired marker lies ahead, while #3 is
1192 * appropriate if the found marker is a future restart marker (indicating
1193 * that we have missed the desired restart marker, probably because it got
1194 * corrupted).
1195 * We apply #2 or #3 if the found marker is a restart marker no more than
1196 * two counts behind or ahead of the expected one. We also apply #2 if the
1197 * found marker is not a legal JPEG marker code (it's certainly bogus data).
1198 * If the found marker is a restart marker more than 2 counts away, we do #1
1199 * (too much risk that the marker is erroneous; with luck we will be able to
1200 * resync at some future point).
1201 * For any valid non-restart JPEG marker, we apply #3. This keeps us from
1202 * overrunning the end of a scan. An implementation limited to single-scan
1203 * files might find it better to apply #2 for markers other than EOI, since
1204 * any other marker would have to be bogus data in that case.
1205 */
1206
1207 GLOBAL(boolean)
1208 jpeg_resync_to_restart (j_decompress_ptr cinfo, int desired)
1209 {
1210 int marker = cinfo->unread_marker;
1211 int action = 1;
1212
1213 /* Always put up a warning. */
1214 WARNMS2(cinfo, JWRN_MUST_RESYNC, marker, desired);
1215
1216 /* Outer loop handles repeated decision after scanning forward. */
1217 for (;;) {
1218 if (marker < (int) M_SOF0)
1219 action = 2; /* invalid marker */
1220 else if (marker < (int) M_RST0 || marker > (int) M_RST7)
1221 action = 3; /* valid non-restart marker */
1222 else {
1223 if (marker == ((int) M_RST0 + ((desired+1) & 7)) ||
1224 marker == ((int) M_RST0 + ((desired+2) & 7)))
1225 action = 3; /* one of the next two expected restarts */
1226 else if (marker == ((int) M_RST0 + ((desired-1) & 7)) ||
1227 marker == ((int) M_RST0 + ((desired-2) & 7)))
1228 action = 2; /* a prior restart, so advance */
1229 else
1230 action = 1; /* desired restart or too far away */
1231 }
1232 TRACEMS2(cinfo, 4, JTRC_RECOVERY_ACTION, marker, action);
1233 switch (action) {
1234 case 1:
1235 /* Discard marker and let entropy decoder resume processing. */
1236 cinfo->unread_marker = 0;
1237 return TRUE;
1238 case 2:
1239 /* Scan to the next marker, and repeat the decision loop. */
1240 if (! next_marker(cinfo))
1241 return FALSE;
1242 marker = cinfo->unread_marker;
1243 break;
1244 case 3:
1245 /* Return without advancing past this marker. */
1246 /* Entropy decoder will be forced to process an empty segment. */
1247 return TRUE;
1248 }
1249 } /* end loop */
1250 }
1251
1252
1253 /*
1254 * Reset marker processing state to begin a fresh datastream.
1255 */
1256
1257 METHODDEF(void)
1258 reset_marker_reader (j_decompress_ptr cinfo)
1259 {
1260 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1261
1262 cinfo->comp_info = NULL; /* until allocated by get_sof */
1263 cinfo->input_scan_number = 0; /* no SOS seen yet */
1264 cinfo->unread_marker = 0; /* no pending marker */
1265 marker->pub.saw_SOI = FALSE; /* set internal state too */
1266 marker->pub.saw_SOF = FALSE;
1267 marker->pub.discarded_bytes = 0;
1268 marker->cur_marker = NULL;
1269 }
1270
1271
1272 /*
1273 * Initialize the marker reader module.
1274 * This is called only once, when the decompression object is created.
1275 */
1276
1277 GLOBAL(void)
1278 jinit_marker_reader (j_decompress_ptr cinfo)
1279 {
1280 my_marker_ptr marker;
1281 int i;
1282
1283 /* Create subobject in permanent pool */
1284 marker = (my_marker_ptr)
1285 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
1286 SIZEOF(my_marker_reader));
1287 cinfo->marker = (struct jpeg_marker_reader *) marker;
1288 /* Initialize public method pointers */
1289 marker->pub.reset_marker_reader = reset_marker_reader;
1290 marker->pub.read_markers = read_markers;
1291 marker->pub.read_restart_marker = read_restart_marker;
1292 /* Initialize COM/APPn processing.
1293 * By default, we examine and then discard APP0 and APP14,
1294 * but simply discard COM and all other APPn.
1295 */
1296 marker->process_COM = skip_variable;
1297 marker->length_limit_COM = 0;
1298 for (i = 0; i < 16; i++) {
1299 marker->process_APPn[i] = skip_variable;
1300 marker->length_limit_APPn[i] = 0;
1301 }
1302 marker->process_APPn[0] = get_interesting_appn;
1303 marker->process_APPn[14] = get_interesting_appn;
1304 /* Reset marker processing state */
1305 reset_marker_reader(cinfo);
1306 }
1307
1308
1309 /*
1310 * Control saving of COM and APPn markers into marker_list.
1311 */
1312
1313 #ifdef SAVE_MARKERS_SUPPORTED
1314
1315 GLOBAL(void)
1316 jpeg_save_markers (j_decompress_ptr cinfo, int marker_code,
1317 unsigned int length_limit)
1318 {
1319 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1320 long maxlength;
1321 jpeg_marker_parser_method processor;
1322
1323 /* Length limit mustn't be larger than what we can allocate
1324 * (should only be a concern in a 16-bit environment).
1325 */
1326 maxlength = cinfo->mem->max_alloc_chunk - SIZEOF(struct jpeg_marker_struct);
1327 if (((long) length_limit) > maxlength)
1328 length_limit = (unsigned int) maxlength;
1329
1330 /* Choose processor routine to use.
1331 * APP0/APP14 have special requirements.
1332 */
1333 if (length_limit) {
1334 processor = save_marker;
1335 /* If saving APP0/APP14, save at least enough for our internal use. */
1336 if (marker_code == (int) M_APP0 && length_limit < APP0_DATA_LEN)
1337 length_limit = APP0_DATA_LEN;
1338 else if (marker_code == (int) M_APP14 && length_limit < APP14_DATA_LEN)
1339 length_limit = APP14_DATA_LEN;
1340 } else {
1341 processor = skip_variable;
1342 /* If discarding APP0/APP14, use our regular on-the-fly processor. */
1343 if (marker_code == (int) M_APP0 || marker_code == (int) M_APP14)
1344 processor = get_interesting_appn;
1345 }
1346
1347 if (marker_code == (int) M_COM) {
1348 marker->process_COM = processor;
1349 marker->length_limit_COM = length_limit;
1350 } else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15) {
1351 marker->process_APPn[marker_code - (int) M_APP0] = processor;
1352 marker->length_limit_APPn[marker_code - (int) M_APP0] = length_limit;
1353 } else
1354 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
1355 }
1356
1357 #endif /* SAVE_MARKERS_SUPPORTED */
1358
1359
1360 /*
1361 * Install a special processing method for COM or APPn markers.
1362 */
1363
1364 GLOBAL(void)
1365 jpeg_set_marker_processor (j_decompress_ptr cinfo, int marker_code,
1366 jpeg_marker_parser_method routine)
1367 {
1368 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1369
1370 if (marker_code == (int) M_COM)
1371 marker->process_COM = routine;
1372 else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15)
1373 marker->process_APPn[marker_code - (int) M_APP0] = routine;
1374 else
1375 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
1376 }

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