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 * Lossless JPEG Modifications:
7 * Copyright (C) 1999, Ken Murchison.
8 * libjpeg-turbo Modifications:
9 * Copyright (C) 2012, 2015, 2022, 2024, D. R. Commander.
10 * For conditions of distribution and use, see the accompanying README.ijg
11 * file.
12 *
13 * This file contains routines to decode JPEG datastream markers.
14 * Most of the complexity arises from our desire to support input
15 * suspension: if not all of the data for a marker is available,
16 * we must exit back to the application. On resumption, we reprocess
17 * the marker.
18 */
19
20 #define JPEG_INTERNALS
21 #include "jinclude.h"
22 #include "jpeglib.h"
23
24
25 typedef enum { /* JPEG marker codes */
26 M_SOF0 = 0xc0,
27 M_SOF1 = 0xc1,
28 M_SOF2 = 0xc2,
29 M_SOF3 = 0xc3,
30
31 M_SOF5 = 0xc5,
32 M_SOF6 = 0xc6,
33 M_SOF7 = 0xc7,
34
35 M_JPG = 0xc8,
36 M_SOF9 = 0xc9,
37 M_SOF10 = 0xca,
38 M_SOF11 = 0xcb,
39
40 M_SOF13 = 0xcd,
41 M_SOF14 = 0xce,
42 M_SOF15 = 0xcf,
43
44 M_DHT = 0xc4,
45
46 M_DAC = 0xcc,
47
48 M_RST0 = 0xd0,
49 M_RST1 = 0xd1,
50 M_RST2 = 0xd2,
51 M_RST3 = 0xd3,
52 M_RST4 = 0xd4,
53 M_RST5 = 0xd5,
54 M_RST6 = 0xd6,
55 M_RST7 = 0xd7,
56
57 M_SOI = 0xd8,
58 M_EOI = 0xd9,
59 M_SOS = 0xda,
60 M_DQT = 0xdb,
61 M_DNL = 0xdc,
62 M_DRI = 0xdd,
63 M_DHP = 0xde,
64 M_EXP = 0xdf,
65
66 M_APP0 = 0xe0,
67 M_APP1 = 0xe1,
68 M_APP2 = 0xe2,
69 M_APP3 = 0xe3,
70 M_APP4 = 0xe4,
71 M_APP5 = 0xe5,
72 M_APP6 = 0xe6,
73 M_APP7 = 0xe7,
74 M_APP8 = 0xe8,
75 M_APP9 = 0xe9,
76 M_APP10 = 0xea,
77 M_APP11 = 0xeb,
78 M_APP12 = 0xec,
79 M_APP13 = 0xed,
80 M_APP14 = 0xee,
81 M_APP15 = 0xef,
82
83 M_JPG0 = 0xf0,
84 M_JPG13 = 0xfd,
85 M_COM = 0xfe,
86
87 M_TEM = 0x01,
88
89 M_ERROR = 0x100
90 } JPEG_MARKER;
91
92
93 /* Private state */
94
95 typedef struct {
96 struct jpeg_marker_reader pub; /* public fields */
97
98 /* Application-overridable marker processing methods */
99 jpeg_marker_parser_method process_COM;
100 jpeg_marker_parser_method process_APPn[16];
101
102 /* Limit on marker data length to save for each marker type */
103 unsigned int length_limit_COM;
104 unsigned int length_limit_APPn[16];
105
106 /* Status of COM/APPn marker saving */
107 jpeg_saved_marker_ptr cur_marker; /* NULL if not processing a marker */
108 unsigned int bytes_read; /* data bytes read so far in marker */
109 /* Note: cur_marker is not linked into marker_list until it's all read. */
110 } my_marker_reader;
111
112 typedef my_marker_reader *my_marker_ptr;
113
114
115 /*
116 * Macros for fetching data from the data source module.
117 *
118 * At all times, cinfo->src->next_input_byte and ->bytes_in_buffer reflect
119 * the current restart point; we update them only when we have reached a
120 * suitable place to restart if a suspension occurs.
121 */
122
123 /* Declare and initialize local copies of input pointer/count */
124 #define INPUT_VARS(cinfo) \
125 struct jpeg_source_mgr *datasrc = (cinfo)->src; \
126 const JOCTET *next_input_byte = datasrc->next_input_byte; \
127 size_t bytes_in_buffer = datasrc->bytes_in_buffer
128
129 /* Unload the local copies --- do this only at a restart boundary */
130 #define INPUT_SYNC(cinfo) \
131 ( datasrc->next_input_byte = next_input_byte, \
132 datasrc->bytes_in_buffer = bytes_in_buffer )
133
134 /* Reload the local copies --- used only in MAKE_BYTE_AVAIL */
135 #define INPUT_RELOAD(cinfo) \
136 ( next_input_byte = datasrc->next_input_byte, \
137 bytes_in_buffer = datasrc->bytes_in_buffer )
138
139 /* Internal macro for INPUT_BYTE and INPUT_2BYTES: make a byte available.
140 * Note we do *not* do INPUT_SYNC before calling fill_input_buffer,
141 * but we must reload the local copies after a successful fill.
142 */
143 #define MAKE_BYTE_AVAIL(cinfo, action) \
144 if (bytes_in_buffer == 0) { \
145 if (!(*datasrc->fill_input_buffer) (cinfo)) \
146 { action; } \
147 INPUT_RELOAD(cinfo); \
148 }
149
150 /* Read a byte into variable V.
151 * If must suspend, take the specified action (typically "return FALSE").
152 */
153 #define INPUT_BYTE(cinfo, V, action) \
154 MAKESTMT( MAKE_BYTE_AVAIL(cinfo, action); \
155 bytes_in_buffer--; \
156 V = *next_input_byte++; )
157
158 /* As above, but read two bytes interpreted as an unsigned 16-bit integer.
159 * V should be declared unsigned int or perhaps JLONG.
160 */
161 #define INPUT_2BYTES(cinfo, V, action) \
162 MAKESTMT( MAKE_BYTE_AVAIL(cinfo, action); \
163 bytes_in_buffer--; \
164 V = ((unsigned int)(*next_input_byte++)) << 8; \
165 MAKE_BYTE_AVAIL(cinfo, action); \
166 bytes_in_buffer--; \
167 V += *next_input_byte++; )
168
169
170 /*
171 * Routines to process JPEG markers.
172 *
173 * Entry condition: JPEG marker itself has been read and its code saved
174 * in cinfo->unread_marker; input restart point is just after the marker.
175 *
176 * Exit: if return TRUE, have read and processed any parameters, and have
177 * updated the restart point to point after the parameters.
178 * If return FALSE, was forced to suspend before reaching end of
179 * marker parameters; restart point has not been moved. Same routine
180 * will be called again after application supplies more input data.
181 *
182 * This approach to suspension assumes that all of a marker's parameters
183 * can fit into a single input bufferload. This should hold for "normal"
184 * markers. Some COM/APPn markers might have large parameter segments
185 * that might not fit. If we are simply dropping such a marker, we use
186 * skip_input_data to get past it, and thereby put the problem on the
187 * source manager's shoulders. If we are saving the marker's contents
188 * into memory, we use a slightly different convention: when forced to
189 * suspend, the marker processor updates the restart point to the end of
190 * what it's consumed (ie, the end of the buffer) before returning FALSE.
191 * On resumption, cinfo->unread_marker still contains the marker code,
192 * but the data source will point to the next chunk of marker data.
193 * The marker processor must retain internal state to deal with this.
194 *
195 * Note that we don't bother to avoid duplicate trace messages if a
196 * suspension occurs within marker parameters. Other side effects
197 * require more care.
198 */
199
200
201 LOCAL(boolean)
get_soi(j_decompress_ptr cinfo)202 get_soi(j_decompress_ptr cinfo)
203 /* Process an SOI marker */
204 {
205 int i;
206
207 TRACEMS(cinfo, 1, JTRC_SOI);
208
209 if (cinfo->marker->saw_SOI)
210 ERREXIT(cinfo, JERR_SOI_DUPLICATE);
211
212 /* Reset all parameters that are defined to be reset by SOI */
213
214 for (i = 0; i < NUM_ARITH_TBLS; i++) {
215 cinfo->arith_dc_L[i] = 0;
216 cinfo->arith_dc_U[i] = 1;
217 cinfo->arith_ac_K[i] = 5;
218 }
219 cinfo->restart_interval = 0;
220
221 /* Set initial assumptions for colorspace etc */
222
223 cinfo->jpeg_color_space = JCS_UNKNOWN;
224 cinfo->CCIR601_sampling = FALSE; /* Assume non-CCIR sampling??? */
225
226 cinfo->saw_JFIF_marker = FALSE;
227 cinfo->JFIF_major_version = 1; /* set default JFIF APP0 values */
228 cinfo->JFIF_minor_version = 1;
229 cinfo->density_unit = 0;
230 cinfo->X_density = 1;
231 cinfo->Y_density = 1;
232 cinfo->saw_Adobe_marker = FALSE;
233 cinfo->Adobe_transform = 0;
234
235 cinfo->marker->saw_SOI = TRUE;
236
237 return TRUE;
238 }
239
240
241 LOCAL(boolean)
get_sof(j_decompress_ptr cinfo,boolean is_prog,boolean is_arith)242 get_sof(j_decompress_ptr cinfo, boolean is_prog, boolean is_arith)
243 /* Process a SOFn marker */
244 {
245 JLONG length;
246 int c, ci;
247 jpeg_component_info *compptr;
248 INPUT_VARS(cinfo);
249
250 cinfo->progressive_mode = is_prog;
251 cinfo->arith_code = is_arith;
252
253 INPUT_2BYTES(cinfo, length, return FALSE);
254
255 INPUT_BYTE(cinfo, cinfo->data_precision, return FALSE);
256 INPUT_2BYTES(cinfo, cinfo->image_height, return FALSE);
257 INPUT_2BYTES(cinfo, cinfo->image_width, return FALSE);
258 INPUT_BYTE(cinfo, cinfo->num_components, return FALSE);
259
260 length -= 8;
261
262 TRACEMS4(cinfo, 1, JTRC_SOF, cinfo->unread_marker,
263 (int)cinfo->image_width, (int)cinfo->image_height,
264 cinfo->num_components);
265
266 if (cinfo->marker->saw_SOF)
267 ERREXIT(cinfo, JERR_SOF_DUPLICATE);
268
269 /* We don't support files in which the image height is initially specified */
270 /* as 0 and is later redefined by DNL. As long as we have to check that, */
271 /* might as well have a general sanity check. */
272 if (cinfo->image_height <= 0 || cinfo->image_width <= 0 ||
273 cinfo->num_components <= 0)
274 ERREXIT(cinfo, JERR_EMPTY_IMAGE);
275
276 if (length != (cinfo->num_components * 3))
277 ERREXIT(cinfo, JERR_BAD_LENGTH);
278
279 if (cinfo->comp_info == NULL) /* do only once, even if suspend */
280 cinfo->comp_info = (jpeg_component_info *)(*cinfo->mem->alloc_small)
281 ((j_common_ptr)cinfo, JPOOL_IMAGE,
282 cinfo->num_components * sizeof(jpeg_component_info));
283
284 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
285 ci++, compptr++) {
286 compptr->component_index = ci;
287 INPUT_BYTE(cinfo, compptr->component_id, return FALSE);
288 INPUT_BYTE(cinfo, c, return FALSE);
289 compptr->h_samp_factor = (c >> 4) & 15;
290 compptr->v_samp_factor = (c ) & 15;
291 INPUT_BYTE(cinfo, compptr->quant_tbl_no, return FALSE);
292
293 TRACEMS4(cinfo, 1, JTRC_SOF_COMPONENT,
294 compptr->component_id, compptr->h_samp_factor,
295 compptr->v_samp_factor, compptr->quant_tbl_no);
296 }
297
298 cinfo->marker->saw_SOF = TRUE;
299
300 INPUT_SYNC(cinfo);
301 return TRUE;
302 }
303
304
305 LOCAL(boolean)
get_sos(j_decompress_ptr cinfo)306 get_sos(j_decompress_ptr cinfo)
307 /* Process a SOS marker */
308 {
309 JLONG length;
310 int i, ci, n, c, cc, pi;
311 jpeg_component_info *compptr;
312 INPUT_VARS(cinfo);
313
314 if (!cinfo->marker->saw_SOF)
315 ERREXIT(cinfo, JERR_SOS_NO_SOF);
316
317 INPUT_2BYTES(cinfo, length, return FALSE);
318
319 INPUT_BYTE(cinfo, n, return FALSE); /* Number of components */
320
321 TRACEMS1(cinfo, 1, JTRC_SOS, n);
322
323 if (length != (n * 2 + 6) || n < 1 || n > MAX_COMPS_IN_SCAN)
324 ERREXIT(cinfo, JERR_BAD_LENGTH);
325
326 cinfo->comps_in_scan = n;
327
328 /* Collect the component-spec parameters */
329
330 for (i = 0; i < MAX_COMPS_IN_SCAN; i++)
331 cinfo->cur_comp_info[i] = NULL;
332
333 for (i = 0; i < n; i++) {
334 INPUT_BYTE(cinfo, cc, return FALSE);
335 INPUT_BYTE(cinfo, c, return FALSE);
336
337 for (ci = 0, compptr = cinfo->comp_info;
338 ci < cinfo->num_components && ci < MAX_COMPS_IN_SCAN;
339 ci++, compptr++) {
340 if (cc == compptr->component_id && !cinfo->cur_comp_info[ci])
341 goto id_found;
342 }
343
344 ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc);
345
346 id_found:
347
348 cinfo->cur_comp_info[i] = compptr;
349 compptr->dc_tbl_no = (c >> 4) & 15;
350 compptr->ac_tbl_no = (c ) & 15;
351
352 TRACEMS3(cinfo, 1, JTRC_SOS_COMPONENT, cc,
353 compptr->dc_tbl_no, compptr->ac_tbl_no);
354
355 /* This CSi (cc) should differ from the previous CSi */
356 for (pi = 0; pi < i; pi++) {
357 if (cinfo->cur_comp_info[pi] == compptr) {
358 ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc);
359 }
360 }
361 }
362
363 /* Collect the additional scan parameters Ss, Se, Ah/Al. */
364 INPUT_BYTE(cinfo, c, return FALSE);
365 cinfo->Ss = c;
366 INPUT_BYTE(cinfo, c, return FALSE);
367 cinfo->Se = c;
368 INPUT_BYTE(cinfo, c, return FALSE);
369 cinfo->Ah = (c >> 4) & 15;
370 cinfo->Al = (c ) & 15;
371
372 TRACEMS4(cinfo, 1, JTRC_SOS_PARAMS, cinfo->Ss, cinfo->Se,
373 cinfo->Ah, cinfo->Al);
374
375 /* Prepare to scan data & restart markers */
376 cinfo->marker->next_restart_num = 0;
377
378 /* Count another SOS marker */
379 cinfo->input_scan_number++;
380
381 INPUT_SYNC(cinfo);
382 return TRUE;
383 }
384
385
386 #ifdef D_ARITH_CODING_SUPPORTED
387
388 LOCAL(boolean)
get_dac(j_decompress_ptr cinfo)389 get_dac(j_decompress_ptr cinfo)
390 /* Process a DAC marker */
391 {
392 JLONG length;
393 int index, val;
394 INPUT_VARS(cinfo);
395
396 INPUT_2BYTES(cinfo, length, return FALSE);
397 length -= 2;
398
399 while (length > 0) {
400 INPUT_BYTE(cinfo, index, return FALSE);
401 INPUT_BYTE(cinfo, val, return FALSE);
402
403 length -= 2;
404
405 TRACEMS2(cinfo, 1, JTRC_DAC, index, val);
406
407 if (index < 0 || index >= (2 * NUM_ARITH_TBLS))
408 ERREXIT1(cinfo, JERR_DAC_INDEX, index);
409
410 if (index >= NUM_ARITH_TBLS) { /* define AC table */
411 cinfo->arith_ac_K[index - NUM_ARITH_TBLS] = (UINT8)val;
412 } else { /* define DC table */
413 cinfo->arith_dc_L[index] = (UINT8)(val & 0x0F);
414 cinfo->arith_dc_U[index] = (UINT8)(val >> 4);
415 if (cinfo->arith_dc_L[index] > cinfo->arith_dc_U[index])
416 ERREXIT1(cinfo, JERR_DAC_VALUE, val);
417 }
418 }
419
420 if (length != 0)
421 ERREXIT(cinfo, JERR_BAD_LENGTH);
422
423 INPUT_SYNC(cinfo);
424 return TRUE;
425 }
426
427 #else /* !D_ARITH_CODING_SUPPORTED */
428
429 #define get_dac(cinfo) skip_variable(cinfo)
430
431 #endif /* D_ARITH_CODING_SUPPORTED */
432
433
434 LOCAL(boolean)
get_dht(j_decompress_ptr cinfo)435 get_dht(j_decompress_ptr cinfo)
436 /* Process a DHT marker */
437 {
438 JLONG length;
439 UINT8 bits[17];
440 UINT8 huffval[256];
441 int i, index, count;
442 JHUFF_TBL **htblptr;
443 INPUT_VARS(cinfo);
444
445 INPUT_2BYTES(cinfo, length, return FALSE);
446 length -= 2;
447
448 while (length > 16) {
449 INPUT_BYTE(cinfo, index, return FALSE);
450
451 TRACEMS1(cinfo, 1, JTRC_DHT, index);
452
453 bits[0] = 0;
454 count = 0;
455 for (i = 1; i <= 16; i++) {
456 INPUT_BYTE(cinfo, bits[i], return FALSE);
457 count += bits[i];
458 }
459
460 length -= 1 + 16;
461
462 TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
463 bits[1], bits[2], bits[3], bits[4],
464 bits[5], bits[6], bits[7], bits[8]);
465 TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
466 bits[9], bits[10], bits[11], bits[12],
467 bits[13], bits[14], bits[15], bits[16]);
468
469 /* Here we just do minimal validation of the counts to avoid walking
470 * off the end of our table space. jdhuff.c will check more carefully.
471 */
472 if (count > 256 || ((JLONG)count) > length)
473 ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
474
475 for (i = 0; i < count; i++)
476 INPUT_BYTE(cinfo, huffval[i], return FALSE);
477
478 memset(&huffval[count], 0, (256 - count) * sizeof(UINT8));
479
480 length -= count;
481
482 if (index & 0x10) { /* AC table definition */
483 index -= 0x10;
484 if (index < 0 || index >= NUM_HUFF_TBLS)
485 ERREXIT1(cinfo, JERR_DHT_INDEX, index);
486 htblptr = &cinfo->ac_huff_tbl_ptrs[index];
487 } else { /* DC table definition */
488 if (index < 0 || index >= NUM_HUFF_TBLS)
489 ERREXIT1(cinfo, JERR_DHT_INDEX, index);
490 htblptr = &cinfo->dc_huff_tbl_ptrs[index];
491 }
492
493 if (*htblptr == NULL)
494 *htblptr = jpeg_alloc_huff_table((j_common_ptr)cinfo);
495
496 memcpy((*htblptr)->bits, bits, sizeof((*htblptr)->bits));
497 memcpy((*htblptr)->huffval, huffval, sizeof((*htblptr)->huffval));
498 }
499
500 if (length != 0)
501 ERREXIT(cinfo, JERR_BAD_LENGTH);
502
503 INPUT_SYNC(cinfo);
504 return TRUE;
505 }
506
507
508 LOCAL(boolean)
get_dqt(j_decompress_ptr cinfo)509 get_dqt(j_decompress_ptr cinfo)
510 /* Process a DQT marker */
511 {
512 JLONG length;
513 int n, i, prec;
514 unsigned int tmp;
515 JQUANT_TBL *quant_ptr;
516 INPUT_VARS(cinfo);
517
518 INPUT_2BYTES(cinfo, length, return FALSE);
519 length -= 2;
520
521 while (length > 0) {
522 INPUT_BYTE(cinfo, n, return FALSE);
523 prec = n >> 4;
524 n &= 0x0F;
525
526 TRACEMS2(cinfo, 1, JTRC_DQT, n, prec);
527
528 if (n >= NUM_QUANT_TBLS)
529 ERREXIT1(cinfo, JERR_DQT_INDEX, n);
530
531 if (cinfo->quant_tbl_ptrs[n] == NULL)
532 cinfo->quant_tbl_ptrs[n] = jpeg_alloc_quant_table((j_common_ptr)cinfo);
533 quant_ptr = cinfo->quant_tbl_ptrs[n];
534
535 for (i = 0; i < DCTSIZE2; i++) {
536 if (prec)
537 INPUT_2BYTES(cinfo, tmp, return FALSE);
538 else
539 INPUT_BYTE(cinfo, tmp, return FALSE);
540 /* We convert the zigzag-order table to natural array order. */
541 quant_ptr->quantval[jpeg_natural_order[i]] = (UINT16)tmp;
542 }
543
544 if (cinfo->err->trace_level >= 2) {
545 for (i = 0; i < DCTSIZE2; i += 8) {
546 TRACEMS8(cinfo, 2, JTRC_QUANTVALS,
547 quant_ptr->quantval[i], quant_ptr->quantval[i + 1],
548 quant_ptr->quantval[i + 2], quant_ptr->quantval[i + 3],
549 quant_ptr->quantval[i + 4], quant_ptr->quantval[i + 5],
550 quant_ptr->quantval[i + 6], quant_ptr->quantval[i + 7]);
551 }
552 }
553
554 length -= DCTSIZE2 + 1;
555 if (prec) length -= DCTSIZE2;
556 }
557
558 if (length != 0)
559 ERREXIT(cinfo, JERR_BAD_LENGTH);
560
561 INPUT_SYNC(cinfo);
562 return TRUE;
563 }
564
565
566 LOCAL(boolean)
get_dri(j_decompress_ptr cinfo)567 get_dri(j_decompress_ptr cinfo)
568 /* Process a DRI marker */
569 {
570 JLONG length;
571 unsigned int tmp;
572 INPUT_VARS(cinfo);
573
574 INPUT_2BYTES(cinfo, length, return FALSE);
575
576 if (length != 4)
577 ERREXIT(cinfo, JERR_BAD_LENGTH);
578
579 INPUT_2BYTES(cinfo, tmp, return FALSE);
580
581 TRACEMS1(cinfo, 1, JTRC_DRI, tmp);
582
583 cinfo->restart_interval = tmp;
584
585 INPUT_SYNC(cinfo);
586 return TRUE;
587 }
588
589
590 /*
591 * Routines for processing APPn and COM markers.
592 * These are either saved in memory or discarded, per application request.
593 * APP0 and APP14 are specially checked to see if they are
594 * JFIF and Adobe markers, respectively.
595 */
596
597 #define APP0_DATA_LEN 14 /* Length of interesting data in APP0 */
598 #define APP14_DATA_LEN 12 /* Length of interesting data in APP14 */
599 #define APPN_DATA_LEN 14 /* Must be the largest of the above!! */
600
601
602 LOCAL(void)
examine_app0(j_decompress_ptr cinfo,JOCTET * data,unsigned int datalen,JLONG remaining)603 examine_app0(j_decompress_ptr cinfo, JOCTET *data, unsigned int datalen,
604 JLONG remaining)
605 /* Examine first few bytes from an APP0.
606 * Take appropriate action if it is a JFIF marker.
607 * datalen is # of bytes at data[], remaining is length of rest of marker data.
608 */
609 {
610 JLONG totallen = (JLONG)datalen + remaining;
611
612 if (datalen >= APP0_DATA_LEN &&
613 data[0] == 0x4A &&
614 data[1] == 0x46 &&
615 data[2] == 0x49 &&
616 data[3] == 0x46 &&
617 data[4] == 0) {
618 /* Found JFIF APP0 marker: save info */
619 cinfo->saw_JFIF_marker = TRUE;
620 cinfo->JFIF_major_version = data[5];
621 cinfo->JFIF_minor_version = data[6];
622 cinfo->density_unit = data[7];
623 cinfo->X_density = (data[8] << 8) + data[9];
624 cinfo->Y_density = (data[10] << 8) + data[11];
625 /* Check version.
626 * Major version must be 1, anything else signals an incompatible change.
627 * (We used to treat this as an error, but now it's a nonfatal warning,
628 * because some bozo at Hijaak couldn't read the spec.)
629 * Minor version should be 0..2, but process anyway if newer.
630 */
631 if (cinfo->JFIF_major_version != 1)
632 WARNMS2(cinfo, JWRN_JFIF_MAJOR,
633 cinfo->JFIF_major_version, cinfo->JFIF_minor_version);
634 /* Generate trace messages */
635 TRACEMS5(cinfo, 1, JTRC_JFIF,
636 cinfo->JFIF_major_version, cinfo->JFIF_minor_version,
637 cinfo->X_density, cinfo->Y_density, cinfo->density_unit);
638 /* Validate thumbnail dimensions and issue appropriate messages */
639 if (data[12] | data[13])
640 TRACEMS2(cinfo, 1, JTRC_JFIF_THUMBNAIL, data[12], data[13]);
641 totallen -= APP0_DATA_LEN;
642 if (totallen != ((JLONG)data[12] * (JLONG)data[13] * (JLONG)3))
643 TRACEMS1(cinfo, 1, JTRC_JFIF_BADTHUMBNAILSIZE, (int)totallen);
644 } else if (datalen >= 6 &&
645 data[0] == 0x4A &&
646 data[1] == 0x46 &&
647 data[2] == 0x58 &&
648 data[3] == 0x58 &&
649 data[4] == 0) {
650 /* Found JFIF "JFXX" extension APP0 marker */
651 /* The library doesn't actually do anything with these,
652 * but we try to produce a helpful trace message.
653 */
654 switch (data[5]) {
655 case 0x10:
656 TRACEMS1(cinfo, 1, JTRC_THUMB_JPEG, (int)totallen);
657 break;
658 case 0x11:
659 TRACEMS1(cinfo, 1, JTRC_THUMB_PALETTE, (int)totallen);
660 break;
661 case 0x13:
662 TRACEMS1(cinfo, 1, JTRC_THUMB_RGB, (int)totallen);
663 break;
664 default:
665 TRACEMS2(cinfo, 1, JTRC_JFIF_EXTENSION, 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)
examine_app14(j_decompress_ptr cinfo,JOCTET * data,unsigned int datalen,JLONG remaining)676 examine_app14(j_decompress_ptr cinfo, JOCTET *data, unsigned int datalen,
677 JLONG 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 data[0] == 0x41 &&
687 data[1] == 0x64 &&
688 data[2] == 0x6F &&
689 data[3] == 0x62 &&
690 data[4] == 0x65) {
691 /* Found Adobe APP14 marker */
692 version = (data[5] << 8) + data[6];
693 flags0 = (data[7] << 8) + data[8];
694 flags1 = (data[9] << 8) + data[10];
695 transform = 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)
get_interesting_appn(j_decompress_ptr cinfo)707 get_interesting_appn(j_decompress_ptr cinfo)
708 /* Process an APP0 or APP14 marker without saving it */
709 {
710 JLONG 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 *)b, numtoread, length);
733 break;
734 case M_APP14:
735 examine_app14(cinfo, (JOCTET *)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)
save_marker(j_decompress_ptr cinfo)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 *data;
762 JLONG 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 *)(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 || cinfo->master->marker_list_end == NULL) {
821 cinfo->marker_list = cinfo->master->marker_list_end = cur_marker;
822 } else {
823 cinfo->master->marker_list_end->next = cur_marker;
824 cinfo->master->marker_list_end = 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
858 METHODDEF(boolean)
skip_variable(j_decompress_ptr cinfo)859 skip_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
887 LOCAL(boolean)
next_marker(j_decompress_ptr cinfo)888 next_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
934 LOCAL(boolean)
first_marker(j_decompress_ptr cinfo)935 first_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
965 METHODDEF(int)
read_markers(j_decompress_ptr cinfo)966 read_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
1126 METHODDEF(boolean)
read_restart_marker(j_decompress_ptr cinfo)1127 read_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
1205 GLOBAL(boolean)
jpeg_resync_to_restart(j_decompress_ptr cinfo,int desired)1206 jpeg_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
1255 METHODDEF(void)
reset_marker_reader(j_decompress_ptr cinfo)1256 reset_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
1275 GLOBAL(void)
jinit_marker_reader(j_decompress_ptr cinfo)1276 jinit_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
1313 GLOBAL(void)
jpeg_save_markers(j_decompress_ptr cinfo,int marker_code,unsigned int length_limit)1314 jpeg_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
1362 GLOBAL(void)
jpeg_set_marker_processor(j_decompress_ptr cinfo,int marker_code,jpeg_marker_parser_method routine)1363 jpeg_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