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, 2015, D. R. Commander.
8 * For conditions of distribution and use, see the accompanying README.ijg
9 * file.
10 *
11 * This file contains routines to decode JPEG datastream markers.
12 * Most of the complexity arises from our desire to support input
13 * suspension: if not all of the data for a marker is available,
14 * we must exit back to the application. On resumption, we reprocess
15 * the marker.
16 */
17
18#define JPEG_INTERNALS
19#include "jinclude.h"
20#include "jpeglib.h"
21
22
23typedef enum { /* JPEG marker codes */
24 M_SOF0 = 0xc0,
25 M_SOF1 = 0xc1,
26 M_SOF2 = 0xc2,
27 M_SOF3 = 0xc3,
28
29 M_SOF5 = 0xc5,
30 M_SOF6 = 0xc6,
31 M_SOF7 = 0xc7,
32
33 M_JPG = 0xc8,
34 M_SOF9 = 0xc9,
35 M_SOF10 = 0xca,
36 M_SOF11 = 0xcb,
37
38 M_SOF13 = 0xcd,
39 M_SOF14 = 0xce,
40 M_SOF15 = 0xcf,
41
42 M_DHT = 0xc4,
43
44 M_DAC = 0xcc,
45
46 M_RST0 = 0xd0,
47 M_RST1 = 0xd1,
48 M_RST2 = 0xd2,
49 M_RST3 = 0xd3,
50 M_RST4 = 0xd4,
51 M_RST5 = 0xd5,
52 M_RST6 = 0xd6,
53 M_RST7 = 0xd7,
54
55 M_SOI = 0xd8,
56 M_EOI = 0xd9,
57 M_SOS = 0xda,
58 M_DQT = 0xdb,
59 M_DNL = 0xdc,
60 M_DRI = 0xdd,
61 M_DHP = 0xde,
62 M_EXP = 0xdf,
63
64 M_APP0 = 0xe0,
65 M_APP1 = 0xe1,
66 M_APP2 = 0xe2,
67 M_APP3 = 0xe3,
68 M_APP4 = 0xe4,
69 M_APP5 = 0xe5,
70 M_APP6 = 0xe6,
71 M_APP7 = 0xe7,
72 M_APP8 = 0xe8,
73 M_APP9 = 0xe9,
74 M_APP10 = 0xea,
75 M_APP11 = 0xeb,
76 M_APP12 = 0xec,
77 M_APP13 = 0xed,
78 M_APP14 = 0xee,
79 M_APP15 = 0xef,
80
81 M_JPG0 = 0xf0,
82 M_JPG13 = 0xfd,
83 M_COM = 0xfe,
84
85 M_TEM = 0x01,
86
87 M_ERROR = 0x100
88} JPEG_MARKER;
89
90
91/* Private state */
92
93typedef struct {
94 struct jpeg_marker_reader pub; /* public fields */
95
96 /* Application-overridable marker processing methods */
97 jpeg_marker_parser_method process_COM;
98 jpeg_marker_parser_method process_APPn[16];
99
100 /* Limit on marker data length to save for each marker type */
101 unsigned int length_limit_COM;
102 unsigned int length_limit_APPn[16];
103
104 /* Status of COM/APPn marker saving */
105 jpeg_saved_marker_ptr cur_marker; /* NULL if not processing a marker */
106 unsigned int bytes_read; /* data bytes read so far in marker */
107 /* Note: cur_marker is not linked into marker_list until it's all read. */
108} my_marker_reader;
109
110typedef my_marker_reader *my_marker_ptr;
111
112
113/*
114 * Macros for fetching data from the data source module.
115 *
116 * At all times, cinfo->src->next_input_byte and ->bytes_in_buffer reflect
117 * the current restart point; we update them only when we have reached a
118 * suitable place to restart if a suspension occurs.
119 */
120
121/* Declare and initialize local copies of input pointer/count */
122#define INPUT_VARS(cinfo) \
123 struct jpeg_source_mgr *datasrc = (cinfo)->src; \
124 const JOCTET *next_input_byte = datasrc->next_input_byte; \
125 size_t bytes_in_buffer = datasrc->bytes_in_buffer
126
127/* Unload the local copies --- do this only at a restart boundary */
128#define INPUT_SYNC(cinfo) \
129 ( datasrc->next_input_byte = next_input_byte, \
130 datasrc->bytes_in_buffer = bytes_in_buffer )
131
132/* Reload the local copies --- used only in MAKE_BYTE_AVAIL */
133#define INPUT_RELOAD(cinfo) \
134 ( next_input_byte = datasrc->next_input_byte, \
135 bytes_in_buffer = datasrc->bytes_in_buffer )
136
137/* Internal macro for INPUT_BYTE and INPUT_2BYTES: make a byte available.
138 * Note we do *not* do INPUT_SYNC before calling fill_input_buffer,
139 * but we must reload the local copies after a successful fill.
140 */
141#define MAKE_BYTE_AVAIL(cinfo, action) \
142 if (bytes_in_buffer == 0) { \
143 if (!(*datasrc->fill_input_buffer) (cinfo)) \
144 { action; } \
145 INPUT_RELOAD(cinfo); \
146 }
147
148/* Read a byte into variable V.
149 * If must suspend, take the specified action (typically "return FALSE").
150 */
151#define INPUT_BYTE(cinfo, V, action) \
152 MAKESTMT( MAKE_BYTE_AVAIL(cinfo, action); \
153 bytes_in_buffer--; \
154 V = *next_input_byte++; )
155
156/* As above, but read two bytes interpreted as an unsigned 16-bit integer.
157 * V should be declared unsigned int or perhaps JLONG.
158 */
159#define INPUT_2BYTES(cinfo, V, action) \
160 MAKESTMT( MAKE_BYTE_AVAIL(cinfo, action); \
161 bytes_in_buffer--; \
162 V = ((unsigned int)(*next_input_byte++)) << 8; \
163 MAKE_BYTE_AVAIL(cinfo, action); \
164 bytes_in_buffer--; \
165 V += *next_input_byte++; )
166
167
168/*
169 * Routines to process JPEG markers.
170 *
171 * Entry condition: JPEG marker itself has been read and its code saved
172 * in cinfo->unread_marker; input restart point is just after the marker.
173 *
174 * Exit: if return TRUE, have read and processed any parameters, and have
175 * updated the restart point to point after the parameters.
176 * If return FALSE, was forced to suspend before reaching end of
177 * marker parameters; restart point has not been moved. Same routine
178 * will be called again after application supplies more input data.
179 *
180 * This approach to suspension assumes that all of a marker's parameters
181 * can fit into a single input bufferload. This should hold for "normal"
182 * markers. Some COM/APPn markers might have large parameter segments
183 * that might not fit. If we are simply dropping such a marker, we use
184 * skip_input_data to get past it, and thereby put the problem on the
185 * source manager's shoulders. If we are saving the marker's contents
186 * into memory, we use a slightly different convention: when forced to
187 * suspend, the marker processor updates the restart point to the end of
188 * what it's consumed (ie, the end of the buffer) before returning FALSE.
189 * On resumption, cinfo->unread_marker still contains the marker code,
190 * but the data source will point to the next chunk of marker data.
191 * The marker processor must retain internal state to deal with this.
192 *
193 * Note that we don't bother to avoid duplicate trace messages if a
194 * suspension occurs within marker parameters. Other side effects
195 * require more care.
196 */
197
198
199LOCAL(boolean)
200get_soi(j_decompress_ptr cinfo)
201/* Process an SOI marker */
202{
203 int i;
204
205 TRACEMS(cinfo, 1, JTRC_SOI);
206
207 if (cinfo->marker->saw_SOI)
208 ERREXIT(cinfo, JERR_SOI_DUPLICATE);
209
210 /* Reset all parameters that are defined to be reset by SOI */
211
212 for (i = 0; i < NUM_ARITH_TBLS; i++) {
213 cinfo->arith_dc_L[i] = 0;
214 cinfo->arith_dc_U[i] = 1;
215 cinfo->arith_ac_K[i] = 5;
216 }
217 cinfo->restart_interval = 0;
218
219 /* Set initial assumptions for colorspace etc */
220
221 cinfo->jpeg_color_space = JCS_UNKNOWN;
222 cinfo->CCIR601_sampling = FALSE; /* Assume non-CCIR sampling??? */
223
224 cinfo->saw_JFIF_marker = FALSE;
225 cinfo->JFIF_major_version = 1; /* set default JFIF APP0 values */
226 cinfo->JFIF_minor_version = 1;
227 cinfo->density_unit = 0;
228 cinfo->X_density = 1;
229 cinfo->Y_density = 1;
230 cinfo->saw_Adobe_marker = FALSE;
231 cinfo->Adobe_transform = 0;
232
233 cinfo->marker->saw_SOI = TRUE;
234
235 return TRUE;
236}
237
238
239LOCAL(boolean)
240get_sof(j_decompress_ptr cinfo, boolean is_prog, boolean is_arith)
241/* Process a SOFn marker */
242{
243 JLONG length;
244 int c, ci;
245 jpeg_component_info *compptr;
246 INPUT_VARS(cinfo);
247
248 cinfo->progressive_mode = is_prog;
249 cinfo->arith_code = is_arith;
250
251 INPUT_2BYTES(cinfo, length, return FALSE);
252
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);
257
258 length -= 8;
259
260 TRACEMS4(cinfo, 1, JTRC_SOF, cinfo->unread_marker,
261 (int)cinfo->image_width, (int)cinfo->image_height,
262 cinfo->num_components);
263
264 if (cinfo->marker->saw_SOF)
265 ERREXIT(cinfo, JERR_SOF_DUPLICATE);
266
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);
273
274 if (length != (cinfo->num_components * 3))
275 ERREXIT(cinfo, JERR_BAD_LENGTH);
276
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));
281
282 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
283 ci++, compptr++) {
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);
290
291 TRACEMS4(cinfo, 1, JTRC_SOF_COMPONENT,
292 compptr->component_id, compptr->h_samp_factor,
293 compptr->v_samp_factor, compptr->quant_tbl_no);
294 }
295
296 cinfo->marker->saw_SOF = TRUE;
297
298 INPUT_SYNC(cinfo);
299 return TRUE;
300}
301
302
303LOCAL(boolean)
304get_sos(j_decompress_ptr cinfo)
305/* Process a SOS marker */
306{
307 JLONG length;
308 int i, ci, n, c, cc, pi;
309 jpeg_component_info *compptr;
310 INPUT_VARS(cinfo);
311
312 if (!cinfo->marker->saw_SOF)
313 ERREXIT(cinfo, JERR_SOS_NO_SOF);
314
315 INPUT_2BYTES(cinfo, length, return FALSE);
316
317 INPUT_BYTE(cinfo, n, return FALSE); /* Number of components */
318
319 TRACEMS1(cinfo, 1, JTRC_SOS, n);
320
321 if (length != (n * 2 + 6) || n < 1 || n > MAX_COMPS_IN_SCAN)
322 ERREXIT(cinfo, JERR_BAD_LENGTH);
323
324 cinfo->comps_in_scan = n;
325
326 /* Collect the component-spec parameters */
327
328 for (i = 0; i < MAX_COMPS_IN_SCAN; i++)
329 cinfo->cur_comp_info[i] = NULL;
330
331 for (i = 0; i < n; i++) {
332 INPUT_BYTE(cinfo, cc, return FALSE);
333 INPUT_BYTE(cinfo, c, return FALSE);
334
335 for (ci = 0, compptr = cinfo->comp_info;
336 ci < cinfo->num_components && ci < MAX_COMPS_IN_SCAN;
337 ci++, compptr++) {
338 if (cc == compptr->component_id && !cinfo->cur_comp_info[ci])
339 goto id_found;
340 }
341
342 ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc);
343
344id_found:
345
346 cinfo->cur_comp_info[i] = compptr;
347 compptr->dc_tbl_no = (c >> 4) & 15;
348 compptr->ac_tbl_no = (c ) & 15;
349
350 TRACEMS3(cinfo, 1, JTRC_SOS_COMPONENT, cc,
351 compptr->dc_tbl_no, compptr->ac_tbl_no);
352
353 /* This CSi (cc) should differ from the previous CSi */
354 for (pi = 0; pi < i; pi++) {
355 if (cinfo->cur_comp_info[pi] == compptr) {
356 ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc);
357 }
358 }
359 }
360
361 /* Collect the additional scan parameters Ss, Se, Ah/Al. */
362 INPUT_BYTE(cinfo, c, return FALSE);
363 cinfo->Ss = c;
364 INPUT_BYTE(cinfo, c, return FALSE);
365 cinfo->Se = c;
366 INPUT_BYTE(cinfo, c, return FALSE);
367 cinfo->Ah = (c >> 4) & 15;
368 cinfo->Al = (c ) & 15;
369
370 TRACEMS4(cinfo, 1, JTRC_SOS_PARAMS, cinfo->Ss, cinfo->Se,
371 cinfo->Ah, cinfo->Al);
372
373 /* Prepare to scan data & restart markers */
374 cinfo->marker->next_restart_num = 0;
375
376 /* Count another SOS marker */
377 cinfo->input_scan_number++;
378
379 INPUT_SYNC(cinfo);
380 return TRUE;
381}
382
383
384#ifdef D_ARITH_CODING_SUPPORTED
385
386LOCAL(boolean)
387get_dac(j_decompress_ptr cinfo)
388/* Process a DAC marker */
389{
390 JLONG length;
391 int index, val;
392 INPUT_VARS(cinfo);
393
394 INPUT_2BYTES(cinfo, length, return FALSE);
395 length -= 2;
396
397 while (length > 0) {
398 INPUT_BYTE(cinfo, index, return FALSE);
399 INPUT_BYTE(cinfo, val, return FALSE);
400
401 length -= 2;
402
403 TRACEMS2(cinfo, 1, JTRC_DAC, index, val);
404
405 if (index < 0 || index >= (2 * NUM_ARITH_TBLS))
406 ERREXIT1(cinfo, JERR_DAC_INDEX, index);
407
408 if (index >= NUM_ARITH_TBLS) { /* define AC table */
409 cinfo->arith_ac_K[index - NUM_ARITH_TBLS] = (UINT8)val;
410 } else { /* define DC table */
411 cinfo->arith_dc_L[index] = (UINT8)(val & 0x0F);
412 cinfo->arith_dc_U[index] = (UINT8)(val >> 4);
413 if (cinfo->arith_dc_L[index] > cinfo->arith_dc_U[index])
414 ERREXIT1(cinfo, JERR_DAC_VALUE, val);
415 }
416 }
417
418 if (length != 0)
419 ERREXIT(cinfo, JERR_BAD_LENGTH);
420
421 INPUT_SYNC(cinfo);
422 return TRUE;
423}
424
425#else /* !D_ARITH_CODING_SUPPORTED */
426
427#define get_dac(cinfo) skip_variable(cinfo)
428
429#endif /* D_ARITH_CODING_SUPPORTED */
430
431
432LOCAL(boolean)
433get_dht(j_decompress_ptr cinfo)
434/* Process a DHT marker */
435{
436 JLONG length;
437 UINT8 bits[17];
438 UINT8 huffval[256];
439 int i, index, count;
440 JHUFF_TBL **htblptr;
441 INPUT_VARS(cinfo);
442
443 INPUT_2BYTES(cinfo, length, return FALSE);
444 length -= 2;
445
446 while (length > 16) {
447 INPUT_BYTE(cinfo, index, return FALSE);
448
449 TRACEMS1(cinfo, 1, JTRC_DHT, index);
450
451 bits[0] = 0;
452 count = 0;
453 for (i = 1; i <= 16; i++) {
454 INPUT_BYTE(cinfo, bits[i], return FALSE);
455 count += bits[i];
456 }
457
458 length -= 1 + 16;
459
460 TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
461 bits[1], bits[2], bits[3], bits[4],
462 bits[5], bits[6], bits[7], bits[8]);
463 TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
464 bits[9], bits[10], bits[11], bits[12],
465 bits[13], bits[14], bits[15], bits[16]);
466
467 /* Here we just do minimal validation of the counts to avoid walking
468 * off the end of our table space. jdhuff.c will check more carefully.
469 */
470 if (count > 256 || ((JLONG)count) > length)
471 ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
472
473 for (i = 0; i < count; i++)
474 INPUT_BYTE(cinfo, huffval[i], return FALSE);
475
476 MEMZERO(&huffval[count], (256 - count) * sizeof(UINT8));
477
478 length -= count;
479
480 if (index & 0x10) { /* AC table definition */
481 index -= 0x10;
482 if (index < 0 || index >= NUM_HUFF_TBLS)
483 ERREXIT1(cinfo, JERR_DHT_INDEX, index);
484 htblptr = &cinfo->ac_huff_tbl_ptrs[index];
485 } else { /* DC table definition */
486 if (index < 0 || index >= NUM_HUFF_TBLS)
487 ERREXIT1(cinfo, JERR_DHT_INDEX, index);
488 htblptr = &cinfo->dc_huff_tbl_ptrs[index];
489 }
490
491 if (*htblptr == NULL)
492 *htblptr = jpeg_alloc_huff_table((j_common_ptr)cinfo);
493
494 MEMCOPY((*htblptr)->bits, bits, sizeof((*htblptr)->bits));
495 MEMCOPY((*htblptr)->huffval, huffval, sizeof((*htblptr)->huffval));
496 }
497
498 if (length != 0)
499 ERREXIT(cinfo, JERR_BAD_LENGTH);
500
501 INPUT_SYNC(cinfo);
502 return TRUE;
503}
504
505
506LOCAL(boolean)
507get_dqt(j_decompress_ptr cinfo)
508/* Process a DQT marker */
509{
510 JLONG length;
511 int n, i, prec;
512 unsigned int tmp;
513 JQUANT_TBL *quant_ptr;
514 INPUT_VARS(cinfo);
515
516 INPUT_2BYTES(cinfo, length, return FALSE);
517 length -= 2;
518
519 while (length > 0) {
520 INPUT_BYTE(cinfo, n, return FALSE);
521 prec = n >> 4;
522 n &= 0x0F;
523
524 TRACEMS2(cinfo, 1, JTRC_DQT, n, prec);
525
526 if (n >= NUM_QUANT_TBLS)
527 ERREXIT1(cinfo, JERR_DQT_INDEX, n);
528
529 if (cinfo->quant_tbl_ptrs[n] == NULL)
530 cinfo->quant_tbl_ptrs[n] = jpeg_alloc_quant_table((j_common_ptr)cinfo);
531 quant_ptr = cinfo->quant_tbl_ptrs[n];
532
533 for (i = 0; i < DCTSIZE2; i++) {
534 if (prec)
535 INPUT_2BYTES(cinfo, tmp, return FALSE);
536 else
537 INPUT_BYTE(cinfo, tmp, return FALSE);
538 /* We convert the zigzag-order table to natural array order. */
539 quant_ptr->quantval[jpeg_natural_order[i]] = (UINT16)tmp;
540 }
541
542 if (cinfo->err->trace_level >= 2) {
543 for (i = 0; i < DCTSIZE2; i += 8) {
544 TRACEMS8(cinfo, 2, JTRC_QUANTVALS,
545 quant_ptr->quantval[i], quant_ptr->quantval[i + 1],
546 quant_ptr->quantval[i + 2], quant_ptr->quantval[i + 3],
547 quant_ptr->quantval[i + 4], quant_ptr->quantval[i + 5],
548 quant_ptr->quantval[i + 6], quant_ptr->quantval[i + 7]);
549 }
550 }
551
552 length -= DCTSIZE2 + 1;
553 if (prec) length -= DCTSIZE2;
554 }
555
556 if (length != 0)
557 ERREXIT(cinfo, JERR_BAD_LENGTH);
558
559 INPUT_SYNC(cinfo);
560 return TRUE;
561}
562
563
564LOCAL(boolean)
565get_dri(j_decompress_ptr cinfo)
566/* Process a DRI marker */
567{
568 JLONG length;
569 unsigned int tmp;
570 INPUT_VARS(cinfo);
571
572 INPUT_2BYTES(cinfo, length, return FALSE);
573
574 if (length != 4)
575 ERREXIT(cinfo, JERR_BAD_LENGTH);
576
577 INPUT_2BYTES(cinfo, tmp, return FALSE);
578
579 TRACEMS1(cinfo, 1, JTRC_DRI, tmp);
580
581 cinfo->restart_interval = tmp;
582
583 INPUT_SYNC(cinfo);
584 return TRUE;
585}
586
587
588/*
589 * Routines for processing APPn and COM markers.
590 * These are either saved in memory or discarded, per application request.
591 * APP0 and APP14 are specially checked to see if they are
592 * JFIF and Adobe markers, respectively.
593 */
594
595#define APP0_DATA_LEN 14 /* Length of interesting data in APP0 */
596#define APP14_DATA_LEN 12 /* Length of interesting data in APP14 */
597#define APPN_DATA_LEN 14 /* Must be the largest of the above!! */
598
599
600LOCAL(void)
601examine_app0(j_decompress_ptr cinfo, JOCTET *data, unsigned int datalen,
602 JLONG remaining)
603/* Examine first few bytes from an APP0.
604 * Take appropriate action if it is a JFIF marker.
605 * datalen is # of bytes at data[], remaining is length of rest of marker data.
606 */
607{
608 JLONG totallen = (JLONG)datalen + remaining;
609
610 if (datalen >= APP0_DATA_LEN &&
611 data[0] == 0x4A &&
612 data[1] == 0x46 &&
613 data[2] == 0x49 &&
614 data[3] == 0x46 &&
615 data[4] == 0) {
616 /* Found JFIF APP0 marker: save info */
617 cinfo->saw_JFIF_marker = TRUE;
618 cinfo->JFIF_major_version = data[5];
619 cinfo->JFIF_minor_version = data[6];
620 cinfo->density_unit = data[7];
621 cinfo->X_density = (data[8] << 8) + data[9];
622 cinfo->Y_density = (data[10] << 8) + data[11];
623 /* Check version.
624 * Major version must be 1, anything else signals an incompatible change.
625 * (We used to treat this as an error, but now it's a nonfatal warning,
626 * because some bozo at Hijaak couldn't read the spec.)
627 * Minor version should be 0..2, but process anyway if newer.
628 */
629 if (cinfo->JFIF_major_version != 1)
630 WARNMS2(cinfo, JWRN_JFIF_MAJOR,
631 cinfo->JFIF_major_version, cinfo->JFIF_minor_version);
632 /* Generate trace messages */
633 TRACEMS5(cinfo, 1, JTRC_JFIF,
634 cinfo->JFIF_major_version, cinfo->JFIF_minor_version,
635 cinfo->X_density, cinfo->Y_density, cinfo->density_unit);
636 /* Validate thumbnail dimensions and issue appropriate messages */
637 if (data[12] | data[13])
638 TRACEMS2(cinfo, 1, JTRC_JFIF_THUMBNAIL, data[12], data[13]);
639 totallen -= APP0_DATA_LEN;
640 if (totallen != ((JLONG)data[12] * (JLONG)data[13] * (JLONG)3))
641 TRACEMS1(cinfo, 1, JTRC_JFIF_BADTHUMBNAILSIZE, (int)totallen);
642 } else if (datalen >= 6 &&
643 data[0] == 0x4A &&
644 data[1] == 0x46 &&
645 data[2] == 0x58 &&
646 data[3] == 0x58 &&
647 data[4] == 0) {
648 /* Found JFIF "JFXX" extension APP0 marker */
649 /* The library doesn't actually do anything with these,
650 * but we try to produce a helpful trace message.
651 */
652 switch (data[5]) {
653 case 0x10:
654 TRACEMS1(cinfo, 1, JTRC_THUMB_JPEG, (int)totallen);
655 break;
656 case 0x11:
657 TRACEMS1(cinfo, 1, JTRC_THUMB_PALETTE, (int)totallen);
658 break;
659 case 0x13:
660 TRACEMS1(cinfo, 1, JTRC_THUMB_RGB, (int)totallen);
661 break;
662 default:
663 TRACEMS2(cinfo, 1, JTRC_JFIF_EXTENSION, data[5], (int)totallen);
664 break;
665 }
666 } else {
667 /* Start of APP0 does not match "JFIF" or "JFXX", or too short */
668 TRACEMS1(cinfo, 1, JTRC_APP0, (int)totallen);
669 }
670}
671
672
673LOCAL(void)
674examine_app14(j_decompress_ptr cinfo, JOCTET *data, unsigned int datalen,
675 JLONG remaining)
676/* Examine first few bytes from an APP14.
677 * Take appropriate action if it is an Adobe marker.
678 * datalen is # of bytes at data[], remaining is length of rest of marker data.
679 */
680{
681 unsigned int version, flags0, flags1, transform;
682
683 if (datalen >= APP14_DATA_LEN &&
684 data[0] == 0x41 &&
685 data[1] == 0x64 &&
686 data[2] == 0x6F &&
687 data[3] == 0x62 &&
688 data[4] == 0x65) {
689 /* Found Adobe APP14 marker */
690 version = (data[5] << 8) + data[6];
691 flags0 = (data[7] << 8) + data[8];
692 flags1 = (data[9] << 8) + data[10];
693 transform = data[11];
694 TRACEMS4(cinfo, 1, JTRC_ADOBE, version, flags0, flags1, transform);
695 cinfo->saw_Adobe_marker = TRUE;
696 cinfo->Adobe_transform = (UINT8)transform;
697 } else {
698 /* Start of APP14 does not match "Adobe", or too short */
699 TRACEMS1(cinfo, 1, JTRC_APP14, (int)(datalen + remaining));
700 }
701}
702
703
704METHODDEF(boolean)
705get_interesting_appn(j_decompress_ptr cinfo)
706/* Process an APP0 or APP14 marker without saving it */
707{
708 JLONG length;
709 JOCTET b[APPN_DATA_LEN];
710 unsigned int i, numtoread;
711 INPUT_VARS(cinfo);
712
713 INPUT_2BYTES(cinfo, length, return FALSE);
714 length -= 2;
715
716 /* get the interesting part of the marker data */
717 if (length >= APPN_DATA_LEN)
718 numtoread = APPN_DATA_LEN;
719 else if (length > 0)
720 numtoread = (unsigned int)length;
721 else
722 numtoread = 0;
723 for (i = 0; i < numtoread; i++)
724 INPUT_BYTE(cinfo, b[i], return FALSE);
725 length -= numtoread;
726
727 /* process it */
728 switch (cinfo->unread_marker) {
729 case M_APP0:
730 examine_app0(cinfo, (JOCTET *)b, numtoread, length);
731 break;
732 case M_APP14:
733 examine_app14(cinfo, (JOCTET *)b, numtoread, length);
734 break;
735 default:
736 /* can't get here unless jpeg_save_markers chooses wrong processor */
737 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
738 break;
739 }
740
741 /* skip any remaining data -- could be lots */
742 INPUT_SYNC(cinfo);
743 if (length > 0)
744 (*cinfo->src->skip_input_data) (cinfo, (long)length);
745
746 return TRUE;
747}
748
749
750#ifdef SAVE_MARKERS_SUPPORTED
751
752METHODDEF(boolean)
753save_marker(j_decompress_ptr cinfo)
754/* Save an APPn or COM marker into the marker list */
755{
756 my_marker_ptr marker = (my_marker_ptr)cinfo->marker;
757 jpeg_saved_marker_ptr cur_marker = marker->cur_marker;
758 unsigned int bytes_read, data_length;
759 JOCTET *data;
760 JLONG length = 0;
761 INPUT_VARS(cinfo);
762
763 if (cur_marker == NULL) {
764 /* begin reading a marker */
765 INPUT_2BYTES(cinfo, length, return FALSE);
766 length -= 2;
767 if (length >= 0) { /* watch out for bogus length word */
768 /* figure out how much we want to save */
769 unsigned int limit;
770 if (cinfo->unread_marker == (int)M_COM)
771 limit = marker->length_limit_COM;
772 else
773 limit = marker->length_limit_APPn[cinfo->unread_marker - (int)M_APP0];
774 if ((unsigned int)length < limit)
775 limit = (unsigned int)length;
776 /* allocate and initialize the marker item */
777 cur_marker = (jpeg_saved_marker_ptr)
778 (*cinfo->mem->alloc_large) ((j_common_ptr)cinfo, JPOOL_IMAGE,
779 sizeof(struct jpeg_marker_struct) + limit);
780 cur_marker->next = NULL;
781 cur_marker->marker = (UINT8)cinfo->unread_marker;
782 cur_marker->original_length = (unsigned int)length;
783 cur_marker->data_length = limit;
784 /* data area is just beyond the jpeg_marker_struct */
785 data = cur_marker->data = (JOCTET *)(cur_marker + 1);
786 marker->cur_marker = cur_marker;
787 marker->bytes_read = 0;
788 bytes_read = 0;
789 data_length = limit;
790 } else {
791 /* deal with bogus length word */
792 bytes_read = data_length = 0;
793 data = NULL;
794 }
795 } else {
796 /* resume reading a marker */
797 bytes_read = marker->bytes_read;
798 data_length = cur_marker->data_length;
799 data = cur_marker->data + bytes_read;
800 }
801
802 while (bytes_read < data_length) {
803 INPUT_SYNC(cinfo); /* move the restart point to here */
804 marker->bytes_read = bytes_read;
805 /* If there's not at least one byte in buffer, suspend */
806 MAKE_BYTE_AVAIL(cinfo, return FALSE);
807 /* Copy bytes with reasonable rapidity */
808 while (bytes_read < data_length && bytes_in_buffer > 0) {
809 *data++ = *next_input_byte++;
810 bytes_in_buffer--;
811 bytes_read++;
812 }
813 }
814
815 /* Done reading what we want to read */
816 if (cur_marker != NULL) { /* will be NULL if bogus length word */
817 /* Add new marker to end of list */
818 if (cinfo->marker_list == NULL) {
819 cinfo->marker_list = cur_marker;
820 } else {
821 jpeg_saved_marker_ptr prev = cinfo->marker_list;
822 while (prev->next != NULL)
823 prev = prev->next;
824 prev->next = cur_marker;
825 }
826 /* Reset pointer & calc remaining data length */
827 data = cur_marker->data;
828 length = cur_marker->original_length - data_length;
829 }
830 /* Reset to initial state for next marker */
831 marker->cur_marker = NULL;
832
833 /* Process the marker if interesting; else just make a generic trace msg */
834 switch (cinfo->unread_marker) {
835 case M_APP0:
836 examine_app0(cinfo, data, data_length, length);
837 break;
838 case M_APP14:
839 examine_app14(cinfo, data, data_length, length);
840 break;
841 default:
842 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker,
843 (int)(data_length + length));
844 break;
845 }
846
847 /* skip any remaining data -- could be lots */
848 INPUT_SYNC(cinfo); /* do before skip_input_data */
849 if (length > 0)
850 (*cinfo->src->skip_input_data) (cinfo, (long)length);
851
852 return TRUE;
853}
854
855#endif /* SAVE_MARKERS_SUPPORTED */
856
857
858METHODDEF(boolean)
859skip_variable(j_decompress_ptr cinfo)
860/* Skip over an unknown or uninteresting variable-length marker */
861{
862 JLONG length;
863 INPUT_VARS(cinfo);
864
865 INPUT_2BYTES(cinfo, length, return FALSE);
866 length -= 2;
867
868 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, (int)length);
869
870 INPUT_SYNC(cinfo); /* do before skip_input_data */
871 if (length > 0)
872 (*cinfo->src->skip_input_data) (cinfo, (long)length);
873
874 return TRUE;
875}
876
877
878/*
879 * Find the next JPEG marker, save it in cinfo->unread_marker.
880 * Returns FALSE if had to suspend before reaching a marker;
881 * in that case cinfo->unread_marker is unchanged.
882 *
883 * Note that the result might not be a valid marker code,
884 * but it will never be 0 or FF.
885 */
886
887LOCAL(boolean)
888next_marker(j_decompress_ptr cinfo)
889{
890 int c;
891 INPUT_VARS(cinfo);
892
893 for (;;) {
894 INPUT_BYTE(cinfo, c, return FALSE);
895 /* Skip any non-FF bytes.
896 * This may look a bit inefficient, but it will not occur in a valid file.
897 * We sync after each discarded byte so that a suspending data source
898 * can discard the byte from its buffer.
899 */
900 while (c != 0xFF) {
901 cinfo->marker->discarded_bytes++;
902 INPUT_SYNC(cinfo);
903 INPUT_BYTE(cinfo, c, return FALSE);
904 }
905 /* This loop swallows any duplicate FF bytes. Extra FFs are legal as
906 * pad bytes, so don't count them in discarded_bytes. We assume there
907 * will not be so many consecutive FF bytes as to overflow a suspending
908 * data source's input buffer.
909 */
910 do {
911 INPUT_BYTE(cinfo, c, return FALSE);
912 } while (c == 0xFF);
913 if (c != 0)
914 break; /* found a valid marker, exit loop */
915 /* Reach here if we found a stuffed-zero data sequence (FF/00).
916 * Discard it and loop back to try again.
917 */
918 cinfo->marker->discarded_bytes += 2;
919 INPUT_SYNC(cinfo);
920 }
921
922 if (cinfo->marker->discarded_bytes != 0) {
923 WARNMS2(cinfo, JWRN_EXTRANEOUS_DATA, cinfo->marker->discarded_bytes, c);
924 cinfo->marker->discarded_bytes = 0;
925 }
926
927 cinfo->unread_marker = c;
928
929 INPUT_SYNC(cinfo);
930 return TRUE;
931}
932
933
934LOCAL(boolean)
935first_marker(j_decompress_ptr cinfo)
936/* Like next_marker, but used to obtain the initial SOI marker. */
937/* For this marker, we do not allow preceding garbage or fill; otherwise,
938 * we might well scan an entire input file before realizing it ain't JPEG.
939 * If an application wants to process non-JFIF files, it must seek to the
940 * SOI before calling the JPEG library.
941 */
942{
943 int c, c2;
944 INPUT_VARS(cinfo);
945
946 INPUT_BYTE(cinfo, c, return FALSE);
947 INPUT_BYTE(cinfo, c2, return FALSE);
948 if (c != 0xFF || c2 != (int)M_SOI)
949 ERREXIT2(cinfo, JERR_NO_SOI, c, c2);
950
951 cinfo->unread_marker = c2;
952
953 INPUT_SYNC(cinfo);
954 return TRUE;
955}
956
957
958/*
959 * Read markers until SOS or EOI.
960 *
961 * Returns same codes as are defined for jpeg_consume_input:
962 * JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
963 */
964
965METHODDEF(int)
966read_markers(j_decompress_ptr cinfo)
967{
968 /* Outer loop repeats once for each marker. */
969 for (;;) {
970 /* Collect the marker proper, unless we already did. */
971 /* NB: first_marker() enforces the requirement that SOI appear first. */
972 if (cinfo->unread_marker == 0) {
973 if (!cinfo->marker->saw_SOI) {
974 if (!first_marker(cinfo))
975 return JPEG_SUSPENDED;
976 } else {
977 if (!next_marker(cinfo))
978 return JPEG_SUSPENDED;
979 }
980 }
981 /* At this point cinfo->unread_marker contains the marker code and the
982 * input point is just past the marker proper, but before any parameters.
983 * A suspension will cause us to return with this state still true.
984 */
985 switch (cinfo->unread_marker) {
986 case M_SOI:
987 if (!get_soi(cinfo))
988 return JPEG_SUSPENDED;
989 break;
990
991 case M_SOF0: /* Baseline */
992 case M_SOF1: /* Extended sequential, Huffman */
993 if (!get_sof(cinfo, FALSE, FALSE))
994 return JPEG_SUSPENDED;
995 break;
996
997 case M_SOF2: /* Progressive, Huffman */
998 if (!get_sof(cinfo, TRUE, FALSE))
999 return JPEG_SUSPENDED;
1000 break;
1001
1002 case M_SOF9: /* Extended sequential, arithmetic */
1003 if (!get_sof(cinfo, FALSE, TRUE))
1004 return JPEG_SUSPENDED;
1005 break;
1006
1007 case M_SOF10: /* Progressive, arithmetic */
1008 if (!get_sof(cinfo, TRUE, TRUE))
1009 return JPEG_SUSPENDED;
1010 break;
1011
1012 /* Currently unsupported SOFn types */
1013 case M_SOF3: /* Lossless, Huffman */
1014 case M_SOF5: /* Differential sequential, Huffman */
1015 case M_SOF6: /* Differential progressive, Huffman */
1016 case M_SOF7: /* Differential lossless, Huffman */
1017 case M_JPG: /* Reserved for JPEG extensions */
1018 case M_SOF11: /* Lossless, arithmetic */
1019 case M_SOF13: /* Differential sequential, arithmetic */
1020 case M_SOF14: /* Differential progressive, arithmetic */
1021 case M_SOF15: /* Differential lossless, arithmetic */
1022 ERREXIT1(cinfo, JERR_SOF_UNSUPPORTED, cinfo->unread_marker);
1023 break;
1024
1025 case M_SOS:
1026 if (!get_sos(cinfo))
1027 return JPEG_SUSPENDED;
1028 cinfo->unread_marker = 0; /* processed the marker */
1029 return JPEG_REACHED_SOS;
1030
1031 case M_EOI:
1032 TRACEMS(cinfo, 1, JTRC_EOI);
1033 cinfo->unread_marker = 0; /* processed the marker */
1034 return JPEG_REACHED_EOI;
1035
1036 case M_DAC:
1037 if (!get_dac(cinfo))
1038 return JPEG_SUSPENDED;
1039 break;
1040
1041 case M_DHT:
1042 if (!get_dht(cinfo))
1043 return JPEG_SUSPENDED;
1044 break;
1045
1046 case M_DQT:
1047 if (!get_dqt(cinfo))
1048 return JPEG_SUSPENDED;
1049 break;
1050
1051 case M_DRI:
1052 if (!get_dri(cinfo))
1053 return JPEG_SUSPENDED;
1054 break;
1055
1056 case M_APP0:
1057 case M_APP1:
1058 case M_APP2:
1059 case M_APP3:
1060 case M_APP4:
1061 case M_APP5:
1062 case M_APP6:
1063 case M_APP7:
1064 case M_APP8:
1065 case M_APP9:
1066 case M_APP10:
1067 case M_APP11:
1068 case M_APP12:
1069 case M_APP13:
1070 case M_APP14:
1071 case M_APP15:
1072 if (!(*((my_marker_ptr)cinfo->marker)->process_APPn[
1073 cinfo->unread_marker - (int)M_APP0]) (cinfo))
1074 return JPEG_SUSPENDED;
1075 break;
1076
1077 case M_COM:
1078 if (!(*((my_marker_ptr)cinfo->marker)->process_COM) (cinfo))
1079 return JPEG_SUSPENDED;
1080 break;
1081
1082 case M_RST0: /* these are all parameterless */
1083 case M_RST1:
1084 case M_RST2:
1085 case M_RST3:
1086 case M_RST4:
1087 case M_RST5:
1088 case M_RST6:
1089 case M_RST7:
1090 case M_TEM:
1091 TRACEMS1(cinfo, 1, JTRC_PARMLESS_MARKER, cinfo->unread_marker);
1092 break;
1093
1094 case M_DNL: /* Ignore DNL ... perhaps the wrong thing */
1095 if (!skip_variable(cinfo))
1096 return JPEG_SUSPENDED;
1097 break;
1098
1099 default: /* must be DHP, EXP, JPGn, or RESn */
1100 /* For now, we treat the reserved markers as fatal errors since they are
1101 * likely to be used to signal incompatible JPEG Part 3 extensions.
1102 * Once the JPEG 3 version-number marker is well defined, this code
1103 * ought to change!
1104 */
1105 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
1106 break;
1107 }
1108 /* Successfully processed marker, so reset state variable */
1109 cinfo->unread_marker = 0;
1110 } /* end loop */
1111}
1112
1113
1114/*
1115 * Read a restart marker, which is expected to appear next in the datastream;
1116 * if the marker is not there, take appropriate recovery action.
1117 * Returns FALSE if suspension is required.
1118 *
1119 * This is called by the entropy decoder after it has read an appropriate
1120 * number of MCUs. cinfo->unread_marker may be nonzero if the entropy decoder
1121 * has already read a marker from the data source. Under normal conditions
1122 * cinfo->unread_marker will be reset to 0 before returning; if not reset,
1123 * it holds a marker which the decoder will be unable to read past.
1124 */
1125
1126METHODDEF(boolean)
1127read_restart_marker(j_decompress_ptr cinfo)
1128{
1129 /* Obtain a marker unless we already did. */
1130 /* Note that next_marker will complain if it skips any data. */
1131 if (cinfo->unread_marker == 0) {
1132 if (!next_marker(cinfo))
1133 return FALSE;
1134 }
1135
1136 if (cinfo->unread_marker ==
1137 ((int)M_RST0 + cinfo->marker->next_restart_num)) {
1138 /* Normal case --- swallow the marker and let entropy decoder continue */
1139 TRACEMS1(cinfo, 3, JTRC_RST, cinfo->marker->next_restart_num);
1140 cinfo->unread_marker = 0;
1141 } else {
1142 /* Uh-oh, the restart markers have been messed up. */
1143 /* Let the data source manager determine how to resync. */
1144 if (!(*cinfo->src->resync_to_restart) (cinfo,
1145 cinfo->marker->next_restart_num))
1146 return FALSE;
1147 }
1148
1149 /* Update next-restart state */
1150 cinfo->marker->next_restart_num = (cinfo->marker->next_restart_num + 1) & 7;
1151
1152 return TRUE;
1153}
1154
1155
1156/*
1157 * This is the default resync_to_restart method for data source managers
1158 * to use if they don't have any better approach. Some data source managers
1159 * may be able to back up, or may have additional knowledge about the data
1160 * which permits a more intelligent recovery strategy; such managers would
1161 * presumably supply their own resync method.
1162 *
1163 * read_restart_marker calls resync_to_restart if it finds a marker other than
1164 * the restart marker it was expecting. (This code is *not* used unless
1165 * a nonzero restart interval has been declared.) cinfo->unread_marker is
1166 * the marker code actually found (might be anything, except 0 or FF).
1167 * The desired restart marker number (0..7) is passed as a parameter.
1168 * This routine is supposed to apply whatever error recovery strategy seems
1169 * appropriate in order to position the input stream to the next data segment.
1170 * Note that cinfo->unread_marker is treated as a marker appearing before
1171 * the current data-source input point; usually it should be reset to zero
1172 * before returning.
1173 * Returns FALSE if suspension is required.
1174 *
1175 * This implementation is substantially constrained by wanting to treat the
1176 * input as a data stream; this means we can't back up. Therefore, we have
1177 * only the following actions to work with:
1178 * 1. Simply discard the marker and let the entropy decoder resume at next
1179 * byte of file.
1180 * 2. Read forward until we find another marker, discarding intervening
1181 * data. (In theory we could look ahead within the current bufferload,
1182 * without having to discard data if we don't find the desired marker.
1183 * This idea is not implemented here, in part because it makes behavior
1184 * dependent on buffer size and chance buffer-boundary positions.)
1185 * 3. Leave the marker unread (by failing to zero cinfo->unread_marker).
1186 * This will cause the entropy decoder to process an empty data segment,
1187 * inserting dummy zeroes, and then we will reprocess the marker.
1188 *
1189 * #2 is appropriate if we think the desired marker lies ahead, while #3 is
1190 * appropriate if the found marker is a future restart marker (indicating
1191 * that we have missed the desired restart marker, probably because it got
1192 * corrupted).
1193 * We apply #2 or #3 if the found marker is a restart marker no more than
1194 * two counts behind or ahead of the expected one. We also apply #2 if the
1195 * found marker is not a legal JPEG marker code (it's certainly bogus data).
1196 * If the found marker is a restart marker more than 2 counts away, we do #1
1197 * (too much risk that the marker is erroneous; with luck we will be able to
1198 * resync at some future point).
1199 * For any valid non-restart JPEG marker, we apply #3. This keeps us from
1200 * overrunning the end of a scan. An implementation limited to single-scan
1201 * files might find it better to apply #2 for markers other than EOI, since
1202 * any other marker would have to be bogus data in that case.
1203 */
1204
1205GLOBAL(boolean)
1206jpeg_resync_to_restart(j_decompress_ptr cinfo, int desired)
1207{
1208 int marker = cinfo->unread_marker;
1209 int action = 1;
1210
1211 /* Always put up a warning. */
1212 WARNMS2(cinfo, JWRN_MUST_RESYNC, marker, desired);
1213
1214 /* Outer loop handles repeated decision after scanning forward. */
1215 for (;;) {
1216 if (marker < (int)M_SOF0)
1217 action = 2; /* invalid marker */
1218 else if (marker < (int)M_RST0 || marker > (int)M_RST7)
1219 action = 3; /* valid non-restart marker */
1220 else {
1221 if (marker == ((int)M_RST0 + ((desired + 1) & 7)) ||
1222 marker == ((int)M_RST0 + ((desired + 2) & 7)))
1223 action = 3; /* one of the next two expected restarts */
1224 else if (marker == ((int)M_RST0 + ((desired - 1) & 7)) ||
1225 marker == ((int)M_RST0 + ((desired - 2) & 7)))
1226 action = 2; /* a prior restart, so advance */
1227 else
1228 action = 1; /* desired restart or too far away */
1229 }
1230 TRACEMS2(cinfo, 4, JTRC_RECOVERY_ACTION, marker, action);
1231 switch (action) {
1232 case 1:
1233 /* Discard marker and let entropy decoder resume processing. */
1234 cinfo->unread_marker = 0;
1235 return TRUE;
1236 case 2:
1237 /* Scan to the next marker, and repeat the decision loop. */
1238 if (!next_marker(cinfo))
1239 return FALSE;
1240 marker = cinfo->unread_marker;
1241 break;
1242 case 3:
1243 /* Return without advancing past this marker. */
1244 /* Entropy decoder will be forced to process an empty segment. */
1245 return TRUE;
1246 }
1247 } /* end loop */
1248}
1249
1250
1251/*
1252 * Reset marker processing state to begin a fresh datastream.
1253 */
1254
1255METHODDEF(void)
1256reset_marker_reader(j_decompress_ptr cinfo)
1257{
1258 my_marker_ptr marker = (my_marker_ptr)cinfo->marker;
1259
1260 cinfo->comp_info = NULL; /* until allocated by get_sof */
1261 cinfo->input_scan_number = 0; /* no SOS seen yet */
1262 cinfo->unread_marker = 0; /* no pending marker */
1263 marker->pub.saw_SOI = FALSE; /* set internal state too */
1264 marker->pub.saw_SOF = FALSE;
1265 marker->pub.discarded_bytes = 0;
1266 marker->cur_marker = NULL;
1267}
1268
1269
1270/*
1271 * Initialize the marker reader module.
1272 * This is called only once, when the decompression object is created.
1273 */
1274
1275GLOBAL(void)
1276jinit_marker_reader(j_decompress_ptr cinfo)
1277{
1278 my_marker_ptr marker;
1279 int i;
1280
1281 /* Create subobject in permanent pool */
1282 marker = (my_marker_ptr)
1283 (*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_PERMANENT,
1284 sizeof(my_marker_reader));
1285 cinfo->marker = (struct jpeg_marker_reader *)marker;
1286 /* Initialize public method pointers */
1287 marker->pub.reset_marker_reader = reset_marker_reader;
1288 marker->pub.read_markers = read_markers;
1289 marker->pub.read_restart_marker = read_restart_marker;
1290 /* Initialize COM/APPn processing.
1291 * By default, we examine and then discard APP0 and APP14,
1292 * but simply discard COM and all other APPn.
1293 */
1294 marker->process_COM = skip_variable;
1295 marker->length_limit_COM = 0;
1296 for (i = 0; i < 16; i++) {
1297 marker->process_APPn[i] = skip_variable;
1298 marker->length_limit_APPn[i] = 0;
1299 }
1300 marker->process_APPn[0] = get_interesting_appn;
1301 marker->process_APPn[14] = get_interesting_appn;
1302 /* Reset marker processing state */
1303 reset_marker_reader(cinfo);
1304}
1305
1306
1307/*
1308 * Control saving of COM and APPn markers into marker_list.
1309 */
1310
1311#ifdef SAVE_MARKERS_SUPPORTED
1312
1313GLOBAL(void)
1314jpeg_save_markers(j_decompress_ptr cinfo, int marker_code,
1315 unsigned int length_limit)
1316{
1317 my_marker_ptr marker = (my_marker_ptr)cinfo->marker;
1318 long maxlength;
1319 jpeg_marker_parser_method processor;
1320
1321 /* Length limit mustn't be larger than what we can allocate
1322 * (should only be a concern in a 16-bit environment).
1323 */
1324 maxlength = cinfo->mem->max_alloc_chunk - sizeof(struct jpeg_marker_struct);
1325 if (((long)length_limit) > maxlength)
1326 length_limit = (unsigned int)maxlength;
1327
1328 /* Choose processor routine to use.
1329 * APP0/APP14 have special requirements.
1330 */
1331 if (length_limit) {
1332 processor = save_marker;
1333 /* If saving APP0/APP14, save at least enough for our internal use. */
1334 if (marker_code == (int)M_APP0 && length_limit < APP0_DATA_LEN)
1335 length_limit = APP0_DATA_LEN;
1336 else if (marker_code == (int)M_APP14 && length_limit < APP14_DATA_LEN)
1337 length_limit = APP14_DATA_LEN;
1338 } else {
1339 processor = skip_variable;
1340 /* If discarding APP0/APP14, use our regular on-the-fly processor. */
1341 if (marker_code == (int)M_APP0 || marker_code == (int)M_APP14)
1342 processor = get_interesting_appn;
1343 }
1344
1345 if (marker_code == (int)M_COM) {
1346 marker->process_COM = processor;
1347 marker->length_limit_COM = length_limit;
1348 } else if (marker_code >= (int)M_APP0 && marker_code <= (int)M_APP15) {
1349 marker->process_APPn[marker_code - (int)M_APP0] = processor;
1350 marker->length_limit_APPn[marker_code - (int)M_APP0] = length_limit;
1351 } else
1352 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
1353}
1354
1355#endif /* SAVE_MARKERS_SUPPORTED */
1356
1357
1358/*
1359 * Install a special processing method for COM or APPn markers.
1360 */
1361
1362GLOBAL(void)
1363jpeg_set_marker_processor(j_decompress_ptr cinfo, int marker_code,
1364 jpeg_marker_parser_method routine)
1365{
1366 my_marker_ptr marker = (my_marker_ptr)cinfo->marker;
1367
1368 if (marker_code == (int)M_COM)
1369 marker->process_COM = routine;
1370 else if (marker_code >= (int)M_APP0 && marker_code <= (int)M_APP15)
1371 marker->process_APPn[marker_code - (int)M_APP0] = routine;
1372 else
1373 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
1374}
1375