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
23 typedef 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
93 typedef 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
110 typedef 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 = GETJOCTET(*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) GETJOCTET(*next_input_byte++)) << 8; \
163 MAKE_BYTE_AVAIL(cinfo,action); \
164 bytes_in_buffer--; \
165 V += GETJOCTET(*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
199 LOCAL(boolean)
get_soi(j_decompress_ptr cinfo)200 get_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
239 LOCAL(boolean)
get_sof(j_decompress_ptr cinfo,boolean is_prog,boolean is_arith)240 get_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
303 LOCAL(boolean)
get_sos(j_decompress_ptr cinfo)304 get_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
344 id_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
386 LOCAL(boolean)
get_dac(j_decompress_ptr cinfo)387 get_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
432 LOCAL(boolean)
get_dht(j_decompress_ptr cinfo)433 get_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
506 LOCAL(boolean)
get_dqt(j_decompress_ptr cinfo)507 get_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
564 LOCAL(boolean)
get_dri(j_decompress_ptr cinfo)565 get_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
600 LOCAL(void)
examine_app0(j_decompress_ptr cinfo,JOCTET * data,unsigned int datalen,JLONG remaining)601 examine_app0 (j_decompress_ptr cinfo, JOCTET *data,
602 unsigned int datalen, 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 GETJOCTET(data[0]) == 0x4A &&
612 GETJOCTET(data[1]) == 0x46 &&
613 GETJOCTET(data[2]) == 0x49 &&
614 GETJOCTET(data[3]) == 0x46 &&
615 GETJOCTET(data[4]) == 0) {
616 /* Found JFIF APP0 marker: save info */
617 cinfo->saw_JFIF_marker = TRUE;
618 cinfo->JFIF_major_version = GETJOCTET(data[5]);
619 cinfo->JFIF_minor_version = GETJOCTET(data[6]);
620 cinfo->density_unit = GETJOCTET(data[7]);
621 cinfo->X_density = (GETJOCTET(data[8]) << 8) + GETJOCTET(data[9]);
622 cinfo->Y_density = (GETJOCTET(data[10]) << 8) + GETJOCTET(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 (GETJOCTET(data[12]) | GETJOCTET(data[13]))
638 TRACEMS2(cinfo, 1, JTRC_JFIF_THUMBNAIL,
639 GETJOCTET(data[12]), GETJOCTET(data[13]));
640 totallen -= APP0_DATA_LEN;
641 if (totallen !=
642 ((JLONG)GETJOCTET(data[12]) * (JLONG)GETJOCTET(data[13]) * (JLONG) 3))
643 TRACEMS1(cinfo, 1, JTRC_JFIF_BADTHUMBNAILSIZE, (int) totallen);
644 } else if (datalen >= 6 &&
645 GETJOCTET(data[0]) == 0x4A &&
646 GETJOCTET(data[1]) == 0x46 &&
647 GETJOCTET(data[2]) == 0x58 &&
648 GETJOCTET(data[3]) == 0x58 &&
649 GETJOCTET(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 (GETJOCTET(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,
666 GETJOCTET(data[5]), (int) totallen);
667 break;
668 }
669 } else {
670 /* Start of APP0 does not match "JFIF" or "JFXX", or too short */
671 TRACEMS1(cinfo, 1, JTRC_APP0, (int) totallen);
672 }
673 }
674
675
676 LOCAL(void)
examine_app14(j_decompress_ptr cinfo,JOCTET * data,unsigned int datalen,JLONG remaining)677 examine_app14 (j_decompress_ptr cinfo, JOCTET *data,
678 unsigned int datalen, JLONG remaining)
679 /* Examine first few bytes from an APP14.
680 * Take appropriate action if it is an Adobe marker.
681 * datalen is # of bytes at data[], remaining is length of rest of marker data.
682 */
683 {
684 unsigned int version, flags0, flags1, transform;
685
686 if (datalen >= APP14_DATA_LEN &&
687 GETJOCTET(data[0]) == 0x41 &&
688 GETJOCTET(data[1]) == 0x64 &&
689 GETJOCTET(data[2]) == 0x6F &&
690 GETJOCTET(data[3]) == 0x62 &&
691 GETJOCTET(data[4]) == 0x65) {
692 /* Found Adobe APP14 marker */
693 version = (GETJOCTET(data[5]) << 8) + GETJOCTET(data[6]);
694 flags0 = (GETJOCTET(data[7]) << 8) + GETJOCTET(data[8]);
695 flags1 = (GETJOCTET(data[9]) << 8) + GETJOCTET(data[10]);
696 transform = GETJOCTET(data[11]);
697 TRACEMS4(cinfo, 1, JTRC_ADOBE, version, flags0, flags1, transform);
698 cinfo->saw_Adobe_marker = TRUE;
699 cinfo->Adobe_transform = (UINT8) transform;
700 } else {
701 /* Start of APP14 does not match "Adobe", or too short */
702 TRACEMS1(cinfo, 1, JTRC_APP14, (int) (datalen + remaining));
703 }
704 }
705
706
707 METHODDEF(boolean)
get_interesting_appn(j_decompress_ptr cinfo)708 get_interesting_appn (j_decompress_ptr cinfo)
709 /* Process an APP0 or APP14 marker without saving it */
710 {
711 JLONG length;
712 JOCTET b[APPN_DATA_LEN];
713 unsigned int i, numtoread;
714 INPUT_VARS(cinfo);
715
716 INPUT_2BYTES(cinfo, length, return FALSE);
717 length -= 2;
718
719 /* get the interesting part of the marker data */
720 if (length >= APPN_DATA_LEN)
721 numtoread = APPN_DATA_LEN;
722 else if (length > 0)
723 numtoread = (unsigned int) length;
724 else
725 numtoread = 0;
726 for (i = 0; i < numtoread; i++)
727 INPUT_BYTE(cinfo, b[i], return FALSE);
728 length -= numtoread;
729
730 /* process it */
731 switch (cinfo->unread_marker) {
732 case M_APP0:
733 examine_app0(cinfo, (JOCTET *) b, numtoread, length);
734 break;
735 case M_APP14:
736 examine_app14(cinfo, (JOCTET *) b, numtoread, length);
737 break;
738 default:
739 /* can't get here unless jpeg_save_markers chooses wrong processor */
740 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
741 break;
742 }
743
744 /* skip any remaining data -- could be lots */
745 INPUT_SYNC(cinfo);
746 if (length > 0)
747 (*cinfo->src->skip_input_data) (cinfo, (long) length);
748
749 return TRUE;
750 }
751
752
753 #ifdef SAVE_MARKERS_SUPPORTED
754
755 METHODDEF(boolean)
save_marker(j_decompress_ptr cinfo)756 save_marker (j_decompress_ptr cinfo)
757 /* Save an APPn or COM marker into the marker list */
758 {
759 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
760 jpeg_saved_marker_ptr cur_marker = marker->cur_marker;
761 unsigned int bytes_read, data_length;
762 JOCTET *data;
763 JLONG length = 0;
764 INPUT_VARS(cinfo);
765
766 if (cur_marker == NULL) {
767 /* begin reading a marker */
768 INPUT_2BYTES(cinfo, length, return FALSE);
769 length -= 2;
770 if (length >= 0) { /* watch out for bogus length word */
771 /* figure out how much we want to save */
772 unsigned int limit;
773 if (cinfo->unread_marker == (int) M_COM)
774 limit = marker->length_limit_COM;
775 else
776 limit = marker->length_limit_APPn[cinfo->unread_marker - (int) M_APP0];
777 if ((unsigned int) length < limit)
778 limit = (unsigned int) length;
779 /* allocate and initialize the marker item */
780 cur_marker = (jpeg_saved_marker_ptr)
781 (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
782 sizeof(struct jpeg_marker_struct) + limit);
783 cur_marker->next = NULL;
784 cur_marker->marker = (UINT8) cinfo->unread_marker;
785 cur_marker->original_length = (unsigned int) length;
786 cur_marker->data_length = limit;
787 /* data area is just beyond the jpeg_marker_struct */
788 data = cur_marker->data = (JOCTET *) (cur_marker + 1);
789 marker->cur_marker = cur_marker;
790 marker->bytes_read = 0;
791 bytes_read = 0;
792 data_length = limit;
793 } else {
794 /* deal with bogus length word */
795 bytes_read = data_length = 0;
796 data = NULL;
797 }
798 } else {
799 /* resume reading a marker */
800 bytes_read = marker->bytes_read;
801 data_length = cur_marker->data_length;
802 data = cur_marker->data + bytes_read;
803 }
804
805 while (bytes_read < data_length) {
806 INPUT_SYNC(cinfo); /* move the restart point to here */
807 marker->bytes_read = bytes_read;
808 /* If there's not at least one byte in buffer, suspend */
809 MAKE_BYTE_AVAIL(cinfo, return FALSE);
810 /* Copy bytes with reasonable rapidity */
811 while (bytes_read < data_length && bytes_in_buffer > 0) {
812 *data++ = *next_input_byte++;
813 bytes_in_buffer--;
814 bytes_read++;
815 }
816 }
817
818 /* Done reading what we want to read */
819 if (cur_marker != NULL) { /* will be NULL if bogus length word */
820 /* Add new marker to end of list */
821 if (cinfo->marker_list == NULL) {
822 cinfo->marker_list = cur_marker;
823 } else {
824 jpeg_saved_marker_ptr prev = cinfo->marker_list;
825 while (prev->next != NULL)
826 prev = prev->next;
827 prev->next = cur_marker;
828 }
829 /* Reset pointer & calc remaining data length */
830 data = cur_marker->data;
831 length = cur_marker->original_length - data_length;
832 }
833 /* Reset to initial state for next marker */
834 marker->cur_marker = NULL;
835
836 /* Process the marker if interesting; else just make a generic trace msg */
837 switch (cinfo->unread_marker) {
838 case M_APP0:
839 examine_app0(cinfo, data, data_length, length);
840 break;
841 case M_APP14:
842 examine_app14(cinfo, data, data_length, length);
843 break;
844 default:
845 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker,
846 (int) (data_length + length));
847 break;
848 }
849
850 /* skip any remaining data -- could be lots */
851 INPUT_SYNC(cinfo); /* do before skip_input_data */
852 if (length > 0)
853 (*cinfo->src->skip_input_data) (cinfo, (long) length);
854
855 return TRUE;
856 }
857
858 #endif /* SAVE_MARKERS_SUPPORTED */
859
860
861 METHODDEF(boolean)
skip_variable(j_decompress_ptr cinfo)862 skip_variable (j_decompress_ptr cinfo)
863 /* Skip over an unknown or uninteresting variable-length marker */
864 {
865 JLONG length;
866 INPUT_VARS(cinfo);
867
868 INPUT_2BYTES(cinfo, length, return FALSE);
869 length -= 2;
870
871 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, (int) length);
872
873 INPUT_SYNC(cinfo); /* do before skip_input_data */
874 if (length > 0)
875 (*cinfo->src->skip_input_data) (cinfo, (long) length);
876
877 return TRUE;
878 }
879
880
881 /*
882 * Find the next JPEG marker, save it in cinfo->unread_marker.
883 * Returns FALSE if had to suspend before reaching a marker;
884 * in that case cinfo->unread_marker is unchanged.
885 *
886 * Note that the result might not be a valid marker code,
887 * but it will never be 0 or FF.
888 */
889
890 LOCAL(boolean)
next_marker(j_decompress_ptr cinfo)891 next_marker (j_decompress_ptr cinfo)
892 {
893 int c;
894 INPUT_VARS(cinfo);
895
896 for (;;) {
897 INPUT_BYTE(cinfo, c, return FALSE);
898 /* Skip any non-FF bytes.
899 * This may look a bit inefficient, but it will not occur in a valid file.
900 * We sync after each discarded byte so that a suspending data source
901 * can discard the byte from its buffer.
902 */
903 while (c != 0xFF) {
904 cinfo->marker->discarded_bytes++;
905 INPUT_SYNC(cinfo);
906 INPUT_BYTE(cinfo, c, return FALSE);
907 }
908 /* This loop swallows any duplicate FF bytes. Extra FFs are legal as
909 * pad bytes, so don't count them in discarded_bytes. We assume there
910 * will not be so many consecutive FF bytes as to overflow a suspending
911 * data source's input buffer.
912 */
913 do {
914 INPUT_BYTE(cinfo, c, return FALSE);
915 } while (c == 0xFF);
916 if (c != 0)
917 break; /* found a valid marker, exit loop */
918 /* Reach here if we found a stuffed-zero data sequence (FF/00).
919 * Discard it and loop back to try again.
920 */
921 cinfo->marker->discarded_bytes += 2;
922 INPUT_SYNC(cinfo);
923 }
924
925 if (cinfo->marker->discarded_bytes != 0) {
926 WARNMS2(cinfo, JWRN_EXTRANEOUS_DATA, cinfo->marker->discarded_bytes, c);
927 cinfo->marker->discarded_bytes = 0;
928 }
929
930 cinfo->unread_marker = c;
931
932 INPUT_SYNC(cinfo);
933 return TRUE;
934 }
935
936
937 LOCAL(boolean)
first_marker(j_decompress_ptr cinfo)938 first_marker (j_decompress_ptr cinfo)
939 /* Like next_marker, but used to obtain the initial SOI marker. */
940 /* For this marker, we do not allow preceding garbage or fill; otherwise,
941 * we might well scan an entire input file before realizing it ain't JPEG.
942 * If an application wants to process non-JFIF files, it must seek to the
943 * SOI before calling the JPEG library.
944 */
945 {
946 int c, c2;
947 INPUT_VARS(cinfo);
948
949 INPUT_BYTE(cinfo, c, return FALSE);
950 INPUT_BYTE(cinfo, c2, return FALSE);
951 if (c != 0xFF || c2 != (int) M_SOI)
952 ERREXIT2(cinfo, JERR_NO_SOI, c, c2);
953
954 cinfo->unread_marker = c2;
955
956 INPUT_SYNC(cinfo);
957 return TRUE;
958 }
959
960
961 /*
962 * Read markers until SOS or EOI.
963 *
964 * Returns same codes as are defined for jpeg_consume_input:
965 * JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
966 */
967
968 METHODDEF(int)
read_markers(j_decompress_ptr cinfo)969 read_markers (j_decompress_ptr cinfo)
970 {
971 /* Outer loop repeats once for each marker. */
972 for (;;) {
973 /* Collect the marker proper, unless we already did. */
974 /* NB: first_marker() enforces the requirement that SOI appear first. */
975 if (cinfo->unread_marker == 0) {
976 if (! cinfo->marker->saw_SOI) {
977 if (! first_marker(cinfo))
978 return JPEG_SUSPENDED;
979 } else {
980 if (! next_marker(cinfo))
981 return JPEG_SUSPENDED;
982 }
983 }
984 /* At this point cinfo->unread_marker contains the marker code and the
985 * input point is just past the marker proper, but before any parameters.
986 * A suspension will cause us to return with this state still true.
987 */
988 switch (cinfo->unread_marker) {
989 case M_SOI:
990 if (! get_soi(cinfo))
991 return JPEG_SUSPENDED;
992 break;
993
994 case M_SOF0: /* Baseline */
995 case M_SOF1: /* Extended sequential, Huffman */
996 if (! get_sof(cinfo, FALSE, FALSE))
997 return JPEG_SUSPENDED;
998 break;
999
1000 case M_SOF2: /* Progressive, Huffman */
1001 if (! get_sof(cinfo, TRUE, FALSE))
1002 return JPEG_SUSPENDED;
1003 break;
1004
1005 case M_SOF9: /* Extended sequential, arithmetic */
1006 if (! get_sof(cinfo, FALSE, TRUE))
1007 return JPEG_SUSPENDED;
1008 break;
1009
1010 case M_SOF10: /* Progressive, arithmetic */
1011 if (! get_sof(cinfo, TRUE, TRUE))
1012 return JPEG_SUSPENDED;
1013 break;
1014
1015 /* Currently unsupported SOFn types */
1016 case M_SOF3: /* Lossless, Huffman */
1017 case M_SOF5: /* Differential sequential, Huffman */
1018 case M_SOF6: /* Differential progressive, Huffman */
1019 case M_SOF7: /* Differential lossless, Huffman */
1020 case M_JPG: /* Reserved for JPEG extensions */
1021 case M_SOF11: /* Lossless, arithmetic */
1022 case M_SOF13: /* Differential sequential, arithmetic */
1023 case M_SOF14: /* Differential progressive, arithmetic */
1024 case M_SOF15: /* Differential lossless, arithmetic */
1025 ERREXIT1(cinfo, JERR_SOF_UNSUPPORTED, cinfo->unread_marker);
1026 break;
1027
1028 case M_SOS:
1029 if (! get_sos(cinfo))
1030 return JPEG_SUSPENDED;
1031 cinfo->unread_marker = 0; /* processed the marker */
1032 return JPEG_REACHED_SOS;
1033
1034 case M_EOI:
1035 TRACEMS(cinfo, 1, JTRC_EOI);
1036 cinfo->unread_marker = 0; /* processed the marker */
1037 return JPEG_REACHED_EOI;
1038
1039 case M_DAC:
1040 if (! get_dac(cinfo))
1041 return JPEG_SUSPENDED;
1042 break;
1043
1044 case M_DHT:
1045 if (! get_dht(cinfo))
1046 return JPEG_SUSPENDED;
1047 break;
1048
1049 case M_DQT:
1050 if (! get_dqt(cinfo))
1051 return JPEG_SUSPENDED;
1052 break;
1053
1054 case M_DRI:
1055 if (! get_dri(cinfo))
1056 return JPEG_SUSPENDED;
1057 break;
1058
1059 case M_APP0:
1060 case M_APP1:
1061 case M_APP2:
1062 case M_APP3:
1063 case M_APP4:
1064 case M_APP5:
1065 case M_APP6:
1066 case M_APP7:
1067 case M_APP8:
1068 case M_APP9:
1069 case M_APP10:
1070 case M_APP11:
1071 case M_APP12:
1072 case M_APP13:
1073 case M_APP14:
1074 case M_APP15:
1075 if (! (*((my_marker_ptr) cinfo->marker)->process_APPn[
1076 cinfo->unread_marker - (int) M_APP0]) (cinfo))
1077 return JPEG_SUSPENDED;
1078 break;
1079
1080 case M_COM:
1081 if (! (*((my_marker_ptr) cinfo->marker)->process_COM) (cinfo))
1082 return JPEG_SUSPENDED;
1083 break;
1084
1085 case M_RST0: /* these are all parameterless */
1086 case M_RST1:
1087 case M_RST2:
1088 case M_RST3:
1089 case M_RST4:
1090 case M_RST5:
1091 case M_RST6:
1092 case M_RST7:
1093 case M_TEM:
1094 TRACEMS1(cinfo, 1, JTRC_PARMLESS_MARKER, cinfo->unread_marker);
1095 break;
1096
1097 case M_DNL: /* Ignore DNL ... perhaps the wrong thing */
1098 if (! skip_variable(cinfo))
1099 return JPEG_SUSPENDED;
1100 break;
1101
1102 default: /* must be DHP, EXP, JPGn, or RESn */
1103 /* For now, we treat the reserved markers as fatal errors since they are
1104 * likely to be used to signal incompatible JPEG Part 3 extensions.
1105 * Once the JPEG 3 version-number marker is well defined, this code
1106 * ought to change!
1107 */
1108 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
1109 break;
1110 }
1111 /* Successfully processed marker, so reset state variable */
1112 cinfo->unread_marker = 0;
1113 } /* end loop */
1114 }
1115
1116
1117 /*
1118 * Read a restart marker, which is expected to appear next in the datastream;
1119 * if the marker is not there, take appropriate recovery action.
1120 * Returns FALSE if suspension is required.
1121 *
1122 * This is called by the entropy decoder after it has read an appropriate
1123 * number of MCUs. cinfo->unread_marker may be nonzero if the entropy decoder
1124 * has already read a marker from the data source. Under normal conditions
1125 * cinfo->unread_marker will be reset to 0 before returning; if not reset,
1126 * it holds a marker which the decoder will be unable to read past.
1127 */
1128
1129 METHODDEF(boolean)
read_restart_marker(j_decompress_ptr cinfo)1130 read_restart_marker (j_decompress_ptr cinfo)
1131 {
1132 /* Obtain a marker unless we already did. */
1133 /* Note that next_marker will complain if it skips any data. */
1134 if (cinfo->unread_marker == 0) {
1135 if (! next_marker(cinfo))
1136 return FALSE;
1137 }
1138
1139 if (cinfo->unread_marker ==
1140 ((int) M_RST0 + cinfo->marker->next_restart_num)) {
1141 /* Normal case --- swallow the marker and let entropy decoder continue */
1142 TRACEMS1(cinfo, 3, JTRC_RST, cinfo->marker->next_restart_num);
1143 cinfo->unread_marker = 0;
1144 } else {
1145 /* Uh-oh, the restart markers have been messed up. */
1146 /* Let the data source manager determine how to resync. */
1147 if (! (*cinfo->src->resync_to_restart) (cinfo,
1148 cinfo->marker->next_restart_num))
1149 return FALSE;
1150 }
1151
1152 /* Update next-restart state */
1153 cinfo->marker->next_restart_num = (cinfo->marker->next_restart_num + 1) & 7;
1154
1155 return TRUE;
1156 }
1157
1158
1159 /*
1160 * This is the default resync_to_restart method for data source managers
1161 * to use if they don't have any better approach. Some data source managers
1162 * may be able to back up, or may have additional knowledge about the data
1163 * which permits a more intelligent recovery strategy; such managers would
1164 * presumably supply their own resync method.
1165 *
1166 * read_restart_marker calls resync_to_restart if it finds a marker other than
1167 * the restart marker it was expecting. (This code is *not* used unless
1168 * a nonzero restart interval has been declared.) cinfo->unread_marker is
1169 * the marker code actually found (might be anything, except 0 or FF).
1170 * The desired restart marker number (0..7) is passed as a parameter.
1171 * This routine is supposed to apply whatever error recovery strategy seems
1172 * appropriate in order to position the input stream to the next data segment.
1173 * Note that cinfo->unread_marker is treated as a marker appearing before
1174 * the current data-source input point; usually it should be reset to zero
1175 * before returning.
1176 * Returns FALSE if suspension is required.
1177 *
1178 * This implementation is substantially constrained by wanting to treat the
1179 * input as a data stream; this means we can't back up. Therefore, we have
1180 * only the following actions to work with:
1181 * 1. Simply discard the marker and let the entropy decoder resume at next
1182 * byte of file.
1183 * 2. Read forward until we find another marker, discarding intervening
1184 * data. (In theory we could look ahead within the current bufferload,
1185 * without having to discard data if we don't find the desired marker.
1186 * This idea is not implemented here, in part because it makes behavior
1187 * dependent on buffer size and chance buffer-boundary positions.)
1188 * 3. Leave the marker unread (by failing to zero cinfo->unread_marker).
1189 * This will cause the entropy decoder to process an empty data segment,
1190 * inserting dummy zeroes, and then we will reprocess the marker.
1191 *
1192 * #2 is appropriate if we think the desired marker lies ahead, while #3 is
1193 * appropriate if the found marker is a future restart marker (indicating
1194 * that we have missed the desired restart marker, probably because it got
1195 * corrupted).
1196 * We apply #2 or #3 if the found marker is a restart marker no more than
1197 * two counts behind or ahead of the expected one. We also apply #2 if the
1198 * found marker is not a legal JPEG marker code (it's certainly bogus data).
1199 * If the found marker is a restart marker more than 2 counts away, we do #1
1200 * (too much risk that the marker is erroneous; with luck we will be able to
1201 * resync at some future point).
1202 * For any valid non-restart JPEG marker, we apply #3. This keeps us from
1203 * overrunning the end of a scan. An implementation limited to single-scan
1204 * files might find it better to apply #2 for markers other than EOI, since
1205 * any other marker would have to be bogus data in that case.
1206 */
1207
1208 GLOBAL(boolean)
jpeg_resync_to_restart(j_decompress_ptr cinfo,int desired)1209 jpeg_resync_to_restart (j_decompress_ptr cinfo, int desired)
1210 {
1211 int marker = cinfo->unread_marker;
1212 int action = 1;
1213
1214 /* Always put up a warning. */
1215 WARNMS2(cinfo, JWRN_MUST_RESYNC, marker, desired);
1216
1217 /* Outer loop handles repeated decision after scanning forward. */
1218 for (;;) {
1219 if (marker < (int) M_SOF0)
1220 action = 2; /* invalid marker */
1221 else if (marker < (int) M_RST0 || marker > (int) M_RST7)
1222 action = 3; /* valid non-restart marker */
1223 else {
1224 if (marker == ((int) M_RST0 + ((desired+1) & 7)) ||
1225 marker == ((int) M_RST0 + ((desired+2) & 7)))
1226 action = 3; /* one of the next two expected restarts */
1227 else if (marker == ((int) M_RST0 + ((desired-1) & 7)) ||
1228 marker == ((int) M_RST0 + ((desired-2) & 7)))
1229 action = 2; /* a prior restart, so advance */
1230 else
1231 action = 1; /* desired restart or too far away */
1232 }
1233 TRACEMS2(cinfo, 4, JTRC_RECOVERY_ACTION, marker, action);
1234 switch (action) {
1235 case 1:
1236 /* Discard marker and let entropy decoder resume processing. */
1237 cinfo->unread_marker = 0;
1238 return TRUE;
1239 case 2:
1240 /* Scan to the next marker, and repeat the decision loop. */
1241 if (! next_marker(cinfo))
1242 return FALSE;
1243 marker = cinfo->unread_marker;
1244 break;
1245 case 3:
1246 /* Return without advancing past this marker. */
1247 /* Entropy decoder will be forced to process an empty segment. */
1248 return TRUE;
1249 }
1250 } /* end loop */
1251 }
1252
1253
1254 /*
1255 * Reset marker processing state to begin a fresh datastream.
1256 */
1257
1258 METHODDEF(void)
reset_marker_reader(j_decompress_ptr cinfo)1259 reset_marker_reader (j_decompress_ptr cinfo)
1260 {
1261 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1262
1263 cinfo->comp_info = NULL; /* until allocated by get_sof */
1264 cinfo->input_scan_number = 0; /* no SOS seen yet */
1265 cinfo->unread_marker = 0; /* no pending marker */
1266 marker->pub.saw_SOI = FALSE; /* set internal state too */
1267 marker->pub.saw_SOF = FALSE;
1268 marker->pub.discarded_bytes = 0;
1269 marker->cur_marker = NULL;
1270 }
1271
1272
1273 /*
1274 * Initialize the marker reader module.
1275 * This is called only once, when the decompression object is created.
1276 */
1277
1278 GLOBAL(void)
jinit_marker_reader(j_decompress_ptr cinfo)1279 jinit_marker_reader (j_decompress_ptr cinfo)
1280 {
1281 my_marker_ptr marker;
1282 int i;
1283
1284 /* Create subobject in permanent pool */
1285 marker = (my_marker_ptr)
1286 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
1287 sizeof(my_marker_reader));
1288 cinfo->marker = (struct jpeg_marker_reader *) marker;
1289 /* Initialize public method pointers */
1290 marker->pub.reset_marker_reader = reset_marker_reader;
1291 marker->pub.read_markers = read_markers;
1292 marker->pub.read_restart_marker = read_restart_marker;
1293 /* Initialize COM/APPn processing.
1294 * By default, we examine and then discard APP0 and APP14,
1295 * but simply discard COM and all other APPn.
1296 */
1297 marker->process_COM = skip_variable;
1298 marker->length_limit_COM = 0;
1299 for (i = 0; i < 16; i++) {
1300 marker->process_APPn[i] = skip_variable;
1301 marker->length_limit_APPn[i] = 0;
1302 }
1303 marker->process_APPn[0] = get_interesting_appn;
1304 marker->process_APPn[14] = get_interesting_appn;
1305 /* Reset marker processing state */
1306 reset_marker_reader(cinfo);
1307 }
1308
1309
1310 /*
1311 * Control saving of COM and APPn markers into marker_list.
1312 */
1313
1314 #ifdef SAVE_MARKERS_SUPPORTED
1315
1316 GLOBAL(void)
jpeg_save_markers(j_decompress_ptr cinfo,int marker_code,unsigned int length_limit)1317 jpeg_save_markers (j_decompress_ptr cinfo, int marker_code,
1318 unsigned int length_limit)
1319 {
1320 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1321 long maxlength;
1322 jpeg_marker_parser_method processor;
1323
1324 /* Length limit mustn't be larger than what we can allocate
1325 * (should only be a concern in a 16-bit environment).
1326 */
1327 maxlength = cinfo->mem->max_alloc_chunk - sizeof(struct jpeg_marker_struct);
1328 if (((long) length_limit) > maxlength)
1329 length_limit = (unsigned int) maxlength;
1330
1331 /* Choose processor routine to use.
1332 * APP0/APP14 have special requirements.
1333 */
1334 if (length_limit) {
1335 processor = save_marker;
1336 /* If saving APP0/APP14, save at least enough for our internal use. */
1337 if (marker_code == (int) M_APP0 && length_limit < APP0_DATA_LEN)
1338 length_limit = APP0_DATA_LEN;
1339 else if (marker_code == (int) M_APP14 && length_limit < APP14_DATA_LEN)
1340 length_limit = APP14_DATA_LEN;
1341 } else {
1342 processor = skip_variable;
1343 /* If discarding APP0/APP14, use our regular on-the-fly processor. */
1344 if (marker_code == (int) M_APP0 || marker_code == (int) M_APP14)
1345 processor = get_interesting_appn;
1346 }
1347
1348 if (marker_code == (int) M_COM) {
1349 marker->process_COM = processor;
1350 marker->length_limit_COM = length_limit;
1351 } else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15) {
1352 marker->process_APPn[marker_code - (int) M_APP0] = processor;
1353 marker->length_limit_APPn[marker_code - (int) M_APP0] = length_limit;
1354 } else
1355 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
1356 }
1357
1358 #endif /* SAVE_MARKERS_SUPPORTED */
1359
1360
1361 /*
1362 * Install a special processing method for COM or APPn markers.
1363 */
1364
1365 GLOBAL(void)
jpeg_set_marker_processor(j_decompress_ptr cinfo,int marker_code,jpeg_marker_parser_method routine)1366 jpeg_set_marker_processor (j_decompress_ptr cinfo, int marker_code,
1367 jpeg_marker_parser_method routine)
1368 {
1369 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1370
1371 if (marker_code == (int) M_COM)
1372 marker->process_COM = routine;
1373 else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15)
1374 marker->process_APPn[marker_code - (int) M_APP0] = routine;
1375 else
1376 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
1377 }
1378