1 /*
2 * jdmarker.c
3 *
4 * Copyright (C) 1991-1998, Thomas G. Lane.
5 * This file is part of the Independent JPEG Group's software.
6 * For conditions of distribution and use, see the accompanying README file.
7 *
8 * This file contains routines to decode JPEG datastream markers.
9 * Most of the complexity arises from our desire to support input
10 * suspension: if not all of the data for a marker is available,
11 * we must exit back to the application. On resumption, we reprocess
12 * the marker.
13 */
14
15 #define JPEG_INTERNALS
16 #include "jinclude.h"
17 #include "jpeglib.h"
18
19
20 typedef enum { /* JPEG marker codes */
21 M_SOF0 = 0xc0,
22 M_SOF1 = 0xc1,
23 M_SOF2 = 0xc2,
24 M_SOF3 = 0xc3,
25
26 M_SOF5 = 0xc5,
27 M_SOF6 = 0xc6,
28 M_SOF7 = 0xc7,
29
30 M_JPG = 0xc8,
31 M_SOF9 = 0xc9,
32 M_SOF10 = 0xca,
33 M_SOF11 = 0xcb,
34
35 M_SOF13 = 0xcd,
36 M_SOF14 = 0xce,
37 M_SOF15 = 0xcf,
38
39 M_DHT = 0xc4,
40
41 M_DAC = 0xcc,
42
43 M_RST0 = 0xd0,
44 M_RST1 = 0xd1,
45 M_RST2 = 0xd2,
46 M_RST3 = 0xd3,
47 M_RST4 = 0xd4,
48 M_RST5 = 0xd5,
49 M_RST6 = 0xd6,
50 M_RST7 = 0xd7,
51
52 M_SOI = 0xd8,
53 M_EOI = 0xd9,
54 M_SOS = 0xda,
55 M_DQT = 0xdb,
56 M_DNL = 0xdc,
57 M_DRI = 0xdd,
58 M_DHP = 0xde,
59 M_EXP = 0xdf,
60
61 M_APP0 = 0xe0,
62 M_APP1 = 0xe1,
63 M_APP2 = 0xe2,
64 M_APP3 = 0xe3,
65 M_APP4 = 0xe4,
66 M_APP5 = 0xe5,
67 M_APP6 = 0xe6,
68 M_APP7 = 0xe7,
69 M_APP8 = 0xe8,
70 M_APP9 = 0xe9,
71 M_APP10 = 0xea,
72 M_APP11 = 0xeb,
73 M_APP12 = 0xec,
74 M_APP13 = 0xed,
75 M_APP14 = 0xee,
76 M_APP15 = 0xef,
77
78 M_JPG0 = 0xf0,
79 M_JPG13 = 0xfd,
80 M_COM = 0xfe,
81
82 M_TEM = 0x01,
83
84 M_ERROR = 0x100
85 } JPEG_MARKER;
86
87
88 /* Private state */
89
90 typedef struct {
91 struct jpeg_marker_reader pub; /* public fields */
92
93 /* Application-overridable marker processing methods */
94 jpeg_marker_parser_method process_COM;
95 jpeg_marker_parser_method process_APPn[16];
96
97 /* Limit on marker data length to save for each marker type */
98 unsigned int length_limit_COM;
99 unsigned int length_limit_APPn[16];
100
101 /* Status of COM/APPn marker saving */
102 jpeg_saved_marker_ptr cur_marker; /* NULL if not processing a marker */
103 unsigned int bytes_read; /* data bytes read so far in marker */
104 /* Note: cur_marker is not linked into marker_list until it's all read. */
105 } my_marker_reader;
106
107 typedef my_marker_reader * my_marker_ptr;
108
109
110 /*
111 * Macros for fetching data from the data source module.
112 *
113 * At all times, cinfo->src->next_input_byte and ->bytes_in_buffer reflect
114 * the current restart point; we update them only when we have reached a
115 * suitable place to restart if a suspension occurs.
116 */
117
118 /* Declare and initialize local copies of input pointer/count */
119 #define INPUT_VARS(cinfo) \
120 struct jpeg_source_mgr * datasrc = (cinfo)->src; \
121 const JOCTET * next_input_byte = datasrc->next_input_byte; \
122 size_t bytes_in_buffer = datasrc->bytes_in_buffer
123
124 /* Unload the local copies --- do this only at a restart boundary */
125 #define INPUT_SYNC(cinfo) \
126 ( datasrc->next_input_byte = next_input_byte, \
127 datasrc->bytes_in_buffer = bytes_in_buffer )
128
129 /* Reload the local copies --- used only in MAKE_BYTE_AVAIL */
130 #define INPUT_RELOAD(cinfo) \
131 ( next_input_byte = datasrc->next_input_byte, \
132 bytes_in_buffer = datasrc->bytes_in_buffer )
133
134 /* Internal macro for INPUT_BYTE and INPUT_2BYTES: make a byte available.
135 * Note we do *not* do INPUT_SYNC before calling fill_input_buffer,
136 * but we must reload the local copies after a successful fill.
137 */
138 #define MAKE_BYTE_AVAIL(cinfo,action) \
139 if (bytes_in_buffer == 0) { \
140 if (! (*datasrc->fill_input_buffer) (cinfo)) \
141 { action; } \
142 INPUT_RELOAD(cinfo); \
143 }
144
145 /* Read a byte into variable V.
146 * If must suspend, take the specified action (typically "return FALSE").
147 */
148 #define INPUT_BYTE(cinfo,V,action) \
149 MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \
150 bytes_in_buffer--; \
151 V = GETJOCTET(*next_input_byte++); )
152
153 /* As above, but read two bytes interpreted as an unsigned 16-bit integer.
154 * V should be declared unsigned int or perhaps INT32.
155 */
156 #define INPUT_2BYTES(cinfo,V,action) \
157 MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \
158 bytes_in_buffer--; \
159 V = ((unsigned int) GETJOCTET(*next_input_byte++)) << 8; \
160 MAKE_BYTE_AVAIL(cinfo,action); \
161 bytes_in_buffer--; \
162 V += GETJOCTET(*next_input_byte++); )
163
164
165 /*
166 * Routines to process JPEG markers.
167 *
168 * Entry condition: JPEG marker itself has been read and its code saved
169 * in cinfo->unread_marker; input restart point is just after the marker.
170 *
171 * Exit: if return TRUE, have read and processed any parameters, and have
172 * updated the restart point to point after the parameters.
173 * If return FALSE, was forced to suspend before reaching end of
174 * marker parameters; restart point has not been moved. Same routine
175 * will be called again after application supplies more input data.
176 *
177 * This approach to suspension assumes that all of a marker's parameters
178 * can fit into a single input bufferload. This should hold for "normal"
179 * markers. Some COM/APPn markers might have large parameter segments
180 * that might not fit. If we are simply dropping such a marker, we use
181 * skip_input_data to get past it, and thereby put the problem on the
182 * source manager's shoulders. If we are saving the marker's contents
183 * into memory, we use a slightly different convention: when forced to
184 * suspend, the marker processor updates the restart point to the end of
185 * what it's consumed (ie, the end of the buffer) before returning FALSE.
186 * On resumption, cinfo->unread_marker still contains the marker code,
187 * but the data source will point to the next chunk of marker data.
188 * The marker processor must retain internal state to deal with this.
189 *
190 * Note that we don't bother to avoid duplicate trace messages if a
191 * suspension occurs within marker parameters. Other side effects
192 * require more care.
193 */
194
195
196 LOCAL(boolean)
get_soi(j_decompress_ptr cinfo)197 get_soi (j_decompress_ptr cinfo)
198 /* Process an SOI marker */
199 {
200 int i;
201
202 TRACEMS(cinfo, 1, JTRC_SOI);
203
204 if (cinfo->marker->saw_SOI)
205 ERREXIT(cinfo, JERR_SOI_DUPLICATE);
206
207 /* Reset all parameters that are defined to be reset by SOI */
208
209 for (i = 0; i < NUM_ARITH_TBLS; i++) {
210 cinfo->arith_dc_L[i] = 0;
211 cinfo->arith_dc_U[i] = 1;
212 cinfo->arith_ac_K[i] = 5;
213 }
214 cinfo->restart_interval = 0;
215
216 /* Set initial assumptions for colorspace etc */
217
218 cinfo->jpeg_color_space = JCS_UNKNOWN;
219 cinfo->CCIR601_sampling = FALSE; /* Assume non-CCIR sampling??? */
220
221 cinfo->saw_JFIF_marker = FALSE;
222 cinfo->JFIF_major_version = 1; /* set default JFIF APP0 values */
223 cinfo->JFIF_minor_version = 1;
224 cinfo->density_unit = 0;
225 cinfo->X_density = 1;
226 cinfo->Y_density = 1;
227 cinfo->saw_Adobe_marker = FALSE;
228 cinfo->Adobe_transform = 0;
229
230 cinfo->marker->saw_SOI = TRUE;
231
232 return TRUE;
233 }
234
235
236 LOCAL(boolean)
get_sof(j_decompress_ptr cinfo,boolean is_prog,boolean is_arith)237 get_sof (j_decompress_ptr cinfo, boolean is_prog, boolean is_arith)
238 /* Process a SOFn marker */
239 {
240 INT32 length;
241 int c, ci;
242 jpeg_component_info * compptr;
243 /* LiuSunliang added 20111209 */
244 JDIMENSION image_width, image_height;
245 INPUT_VARS(cinfo);
246
247 cinfo->progressive_mode = is_prog;
248 cinfo->arith_code = is_arith;
249
250 INPUT_2BYTES(cinfo, length, return FALSE);
251
252 INPUT_BYTE(cinfo, cinfo->data_precision, return FALSE);
253 INPUT_2BYTES(cinfo, image_height, return FALSE);
254 INPUT_2BYTES(cinfo, image_width, return FALSE);
255 INPUT_BYTE(cinfo, cinfo->num_components, return FALSE);
256
257 if (image_width <= JPEG_MAX_DIMENSION)
258 cinfo->image_width = image_width;
259
260 if (image_height <= JPEG_MAX_DIMENSION)
261 cinfo->image_height = image_height;
262
263 length -= 8;
264
265 TRACEMS4(cinfo, 1, JTRC_SOF, cinfo->unread_marker,
266 (int) cinfo->image_width, (int) cinfo->image_height,
267 cinfo->num_components);
268
269 if (cinfo->marker->saw_SOF)
270 ERREXIT(cinfo, JERR_SOF_DUPLICATE);
271
272 /* We don't support files in which the image height is initially specified */
273 /* as 0 and is later redefined by DNL. As long as we have to check that, */
274 /* might as well have a general sanity check. */
275 if (cinfo->image_height <= 0 || cinfo->image_width <= 0
276 || cinfo->num_components <= 0)
277 ERREXIT(cinfo, JERR_EMPTY_IMAGE);
278
279 if (length != (cinfo->num_components * 3))
280 ERREXIT(cinfo, JERR_BAD_LENGTH);
281
282 if (cinfo->comp_info == NULL) /* do only once, even if suspend */
283 cinfo->comp_info = (jpeg_component_info *) (*cinfo->mem->alloc_small)
284 ((j_common_ptr) cinfo, JPOOL_IMAGE,
285 cinfo->num_components * SIZEOF(jpeg_component_info));
286
287 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
288 ci++, compptr++) {
289 compptr->component_index = ci;
290 INPUT_BYTE(cinfo, compptr->component_id, return FALSE);
291 /* XYQ 2008-03-25: Adobe CMYK JPEG has serious flaw: the K channel has same component id as C channel */
292 {
293 int i;
294 for (i = 0; i < ci; i ++)
295 if (compptr->component_id == cinfo->comp_info[i].component_id) break;
296 if (i < ci)
297 /* Found the error! We replace the id with something unlikely used elsewhere */
298 compptr->component_id += 0xf0;
299 }
300 /* end of modification */
301 INPUT_BYTE(cinfo, c, return FALSE);
302 compptr->h_samp_factor = (c >> 4) & 15;
303 compptr->v_samp_factor = (c ) & 15;
304 INPUT_BYTE(cinfo, compptr->quant_tbl_no, return FALSE);
305
306 TRACEMS4(cinfo, 1, JTRC_SOF_COMPONENT,
307 compptr->component_id, compptr->h_samp_factor,
308 compptr->v_samp_factor, compptr->quant_tbl_no);
309 }
310
311 cinfo->marker->saw_SOF = TRUE;
312
313 INPUT_SYNC(cinfo);
314 return TRUE;
315 }
316
317
318 LOCAL(boolean)
get_sos(j_decompress_ptr cinfo)319 get_sos (j_decompress_ptr cinfo)
320 /* Process a SOS marker */
321 {
322 INT32 length;
323 int i, ci, n, c, cc;
324 jpeg_component_info * compptr;
325 INPUT_VARS(cinfo);
326
327 if (! cinfo->marker->saw_SOF)
328 ERREXIT(cinfo, JERR_SOS_NO_SOF);
329
330 INPUT_2BYTES(cinfo, length, return FALSE);
331
332 INPUT_BYTE(cinfo, n, return FALSE); /* Number of components */
333
334 TRACEMS1(cinfo, 1, JTRC_SOS, n);
335
336 if (length != (n * 2 + 6) || n < 1 || n > MAX_COMPS_IN_SCAN)
337 ERREXIT(cinfo, JERR_BAD_LENGTH);
338
339 cinfo->comps_in_scan = n;
340
341 /* Collect the component-spec parameters */
342
343 for (i = 0; i < n; i++) {
344 INPUT_BYTE(cinfo, cc, return FALSE);
345 INPUT_BYTE(cinfo, c, return FALSE);
346
347 /* XYQ 2008-03-25: Adobe CMYK JPEG has serious flaw: the K channel has same component id as C channel */
348 {
349 int j;
350 for (j = 0; j < i; j ++)
351 if (cc == cinfo->cur_comp_info[j]->component_id) break;
352 if (j < i)
353 /* found the error! */
354 cc += 0xf0;
355 }
356 /* end of modification */
357 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
358 ci++, compptr++) {
359 if (cc == compptr->component_id)
360 goto id_found;
361 }
362
363 ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc);
364
365 id_found:
366
367 cinfo->cur_comp_info[i] = compptr;
368 compptr->dc_tbl_no = (c >> 4) & 15;
369 compptr->ac_tbl_no = (c ) & 15;
370
371 TRACEMS3(cinfo, 1, JTRC_SOS_COMPONENT, cc,
372 compptr->dc_tbl_no, compptr->ac_tbl_no);
373 /* This CSi (cc) should differ from the previous CSi */
374 for (ci = 0; ci < i; ci++) {
375 if (cinfo->cur_comp_info[ci] == compptr)
376 ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc);
377 }
378 }
379
380 /* Collect the additional scan parameters Ss, Se, Ah/Al. */
381 INPUT_BYTE(cinfo, c, return FALSE);
382 cinfo->Ss = c;
383 INPUT_BYTE(cinfo, c, return FALSE);
384 cinfo->Se = c;
385 INPUT_BYTE(cinfo, c, return FALSE);
386 cinfo->Ah = (c >> 4) & 15;
387 cinfo->Al = (c ) & 15;
388
389 TRACEMS4(cinfo, 1, JTRC_SOS_PARAMS, cinfo->Ss, cinfo->Se,
390 cinfo->Ah, cinfo->Al);
391
392 /* Prepare to scan data & restart markers */
393 cinfo->marker->next_restart_num = 0;
394
395 /* Count another SOS marker */
396 cinfo->input_scan_number++;
397
398 INPUT_SYNC(cinfo);
399 return TRUE;
400 }
401
402
403 #ifdef D_ARITH_CODING_SUPPORTED
404
405 LOCAL(boolean)
get_dac(j_decompress_ptr cinfo)406 get_dac (j_decompress_ptr cinfo)
407 /* Process a DAC marker */
408 {
409 INT32 length;
410 int index, val;
411 INPUT_VARS(cinfo);
412
413 INPUT_2BYTES(cinfo, length, return FALSE);
414 length -= 2;
415
416 while (length > 0) {
417 INPUT_BYTE(cinfo, index, return FALSE);
418 INPUT_BYTE(cinfo, val, return FALSE);
419
420 length -= 2;
421
422 TRACEMS2(cinfo, 1, JTRC_DAC, index, val);
423
424 if (index < 0 || index >= (2*NUM_ARITH_TBLS))
425 ERREXIT1(cinfo, JERR_DAC_INDEX, index);
426
427 if (index >= NUM_ARITH_TBLS) { /* define AC table */
428 cinfo->arith_ac_K[index-NUM_ARITH_TBLS] = (UINT8) val;
429 } else { /* define DC table */
430 cinfo->arith_dc_L[index] = (UINT8) (val & 0x0F);
431 cinfo->arith_dc_U[index] = (UINT8) (val >> 4);
432 if (cinfo->arith_dc_L[index] > cinfo->arith_dc_U[index])
433 ERREXIT1(cinfo, JERR_DAC_VALUE, val);
434 }
435 }
436
437 if (length != 0)
438 ERREXIT(cinfo, JERR_BAD_LENGTH);
439
440 INPUT_SYNC(cinfo);
441 return TRUE;
442 }
443
444 #else /* ! D_ARITH_CODING_SUPPORTED */
445
446 #define get_dac(cinfo) skip_variable(cinfo)
447
448 #endif /* D_ARITH_CODING_SUPPORTED */
449
450
451 LOCAL(boolean)
get_dht(j_decompress_ptr cinfo)452 get_dht (j_decompress_ptr cinfo)
453 /* Process a DHT marker */
454 {
455 INT32 length;
456 UINT8 bits[17];
457 UINT8 huffval[256];
458 int i, index, count;
459 JHUFF_TBL **htblptr;
460 INPUT_VARS(cinfo);
461
462 INPUT_2BYTES(cinfo, length, return FALSE);
463 length -= 2;
464
465 while (length > 16) {
466 INPUT_BYTE(cinfo, index, return FALSE);
467
468 TRACEMS1(cinfo, 1, JTRC_DHT, index);
469
470 bits[0] = 0;
471 count = 0;
472 for (i = 1; i <= 16; i++) {
473 INPUT_BYTE(cinfo, bits[i], return FALSE);
474 count += bits[i];
475 }
476
477 length -= 1 + 16;
478
479 TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
480 bits[1], bits[2], bits[3], bits[4],
481 bits[5], bits[6], bits[7], bits[8]);
482 TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
483 bits[9], bits[10], bits[11], bits[12],
484 bits[13], bits[14], bits[15], bits[16]);
485
486 /* Here we just do minimal validation of the counts to avoid walking
487 * off the end of our table space. jdhuff.c will check more carefully.
488 */
489 if (count > 256 || ((INT32) count) > length)
490 ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
491
492 for (i = 0; i < count; i++)
493 INPUT_BYTE(cinfo, huffval[i], return FALSE);
494
495 length -= count;
496
497 if (index & 0x10) { /* AC table definition */
498 index -= 0x10;
499 htblptr = &cinfo->ac_huff_tbl_ptrs[index];
500 } else { /* DC table definition */
501 htblptr = &cinfo->dc_huff_tbl_ptrs[index];
502 }
503
504 if (index < 0 || index >= NUM_HUFF_TBLS)
505 ERREXIT1(cinfo, JERR_DHT_INDEX, index);
506
507 if (*htblptr == NULL)
508 *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
509
510 MEMCOPY((*htblptr)->bits, bits, SIZEOF((*htblptr)->bits));
511 MEMCOPY((*htblptr)->huffval, huffval, SIZEOF((*htblptr)->huffval));
512 }
513
514 if (length != 0)
515 ERREXIT(cinfo, JERR_BAD_LENGTH);
516
517 INPUT_SYNC(cinfo);
518 return TRUE;
519 }
520
521
522 LOCAL(boolean)
get_dqt(j_decompress_ptr cinfo)523 get_dqt (j_decompress_ptr cinfo)
524 /* Process a DQT marker */
525 {
526 INT32 length;
527 int n, i, prec;
528 unsigned int tmp;
529 JQUANT_TBL *quant_ptr;
530 INPUT_VARS(cinfo);
531
532 INPUT_2BYTES(cinfo, length, return FALSE);
533 length -= 2;
534
535 while (length > 0) {
536 INPUT_BYTE(cinfo, n, return FALSE);
537 prec = n >> 4;
538 n &= 0x0F;
539
540 TRACEMS2(cinfo, 1, JTRC_DQT, n, prec);
541
542 if (n >= NUM_QUANT_TBLS)
543 ERREXIT1(cinfo, JERR_DQT_INDEX, n);
544
545 if (cinfo->quant_tbl_ptrs[n] == NULL)
546 cinfo->quant_tbl_ptrs[n] = jpeg_alloc_quant_table((j_common_ptr) cinfo);
547 quant_ptr = cinfo->quant_tbl_ptrs[n];
548
549 for (i = 0; i < DCTSIZE2; i++) {
550 if (prec)
551 INPUT_2BYTES(cinfo, tmp, return FALSE);
552 else
553 INPUT_BYTE(cinfo, tmp, return FALSE);
554 /* We convert the zigzag-order table to natural array order. */
555 quant_ptr->quantval[jpeg_natural_order[i]] = (UINT16) tmp;
556 }
557
558 if (cinfo->err->trace_level >= 2) {
559 for (i = 0; i < DCTSIZE2; i += 8) {
560 TRACEMS8(cinfo, 2, JTRC_QUANTVALS,
561 quant_ptr->quantval[i], quant_ptr->quantval[i+1],
562 quant_ptr->quantval[i+2], quant_ptr->quantval[i+3],
563 quant_ptr->quantval[i+4], quant_ptr->quantval[i+5],
564 quant_ptr->quantval[i+6], quant_ptr->quantval[i+7]);
565 }
566 }
567
568 length -= DCTSIZE2+1;
569 if (prec) length -= DCTSIZE2;
570 }
571
572 if (length != 0)
573 ERREXIT(cinfo, JERR_BAD_LENGTH);
574
575 INPUT_SYNC(cinfo);
576 return TRUE;
577 }
578
579
580 LOCAL(boolean)
get_dri(j_decompress_ptr cinfo)581 get_dri (j_decompress_ptr cinfo)
582 /* Process a DRI marker */
583 {
584 INT32 length;
585 unsigned int tmp;
586 INPUT_VARS(cinfo);
587
588 INPUT_2BYTES(cinfo, length, return FALSE);
589
590 if (length != 4)
591 ERREXIT(cinfo, JERR_BAD_LENGTH);
592
593 INPUT_2BYTES(cinfo, tmp, return FALSE);
594
595 TRACEMS1(cinfo, 1, JTRC_DRI, tmp);
596
597 cinfo->restart_interval = tmp;
598
599 INPUT_SYNC(cinfo);
600 return TRUE;
601 }
602
603
604 /*
605 * Routines for processing APPn and COM markers.
606 * These are either saved in memory or discarded, per application request.
607 * APP0 and APP14 are specially checked to see if they are
608 * JFIF and Adobe markers, respectively.
609 */
610
611 #define APP0_DATA_LEN 14 /* Length of interesting data in APP0 */
612 #define APP14_DATA_LEN 12 /* Length of interesting data in APP14 */
613 #define APPN_DATA_LEN 14 /* Must be the largest of the above!! */
614
615
616 LOCAL(void)
examine_app0(j_decompress_ptr cinfo,JOCTET FAR * data,unsigned int datalen,INT32 remaining)617 examine_app0 (j_decompress_ptr cinfo, JOCTET FAR * data,
618 unsigned int datalen, INT32 remaining)
619 /* Examine first few bytes from an APP0.
620 * Take appropriate action if it is a JFIF marker.
621 * datalen is # of bytes at data[], remaining is length of rest of marker data.
622 */
623 {
624 INT32 totallen = (INT32) datalen + remaining;
625
626 if (datalen >= APP0_DATA_LEN &&
627 GETJOCTET(data[0]) == 0x4A &&
628 GETJOCTET(data[1]) == 0x46 &&
629 GETJOCTET(data[2]) == 0x49 &&
630 GETJOCTET(data[3]) == 0x46 &&
631 GETJOCTET(data[4]) == 0) {
632 /* Found JFIF APP0 marker: save info */
633 cinfo->saw_JFIF_marker = TRUE;
634 cinfo->JFIF_major_version = GETJOCTET(data[5]);
635 cinfo->JFIF_minor_version = GETJOCTET(data[6]);
636 cinfo->density_unit = GETJOCTET(data[7]);
637 cinfo->X_density = (GETJOCTET(data[8]) << 8) + GETJOCTET(data[9]);
638 cinfo->Y_density = (GETJOCTET(data[10]) << 8) + GETJOCTET(data[11]);
639 /* Check version.
640 * Major version must be 1, anything else signals an incompatible change.
641 * (We used to treat this as an error, but now it's a nonfatal warning,
642 * because some bozo at Hijaak couldn't read the spec.)
643 * Minor version should be 0..2, but process anyway if newer.
644 */
645 if (cinfo->JFIF_major_version != 1)
646 WARNMS2(cinfo, JWRN_JFIF_MAJOR,
647 cinfo->JFIF_major_version, cinfo->JFIF_minor_version);
648 /* Generate trace messages */
649 TRACEMS5(cinfo, 1, JTRC_JFIF,
650 cinfo->JFIF_major_version, cinfo->JFIF_minor_version,
651 cinfo->X_density, cinfo->Y_density, cinfo->density_unit);
652 /* Validate thumbnail dimensions and issue appropriate messages */
653 if (GETJOCTET(data[12]) | GETJOCTET(data[13]))
654 TRACEMS2(cinfo, 1, JTRC_JFIF_THUMBNAIL,
655 GETJOCTET(data[12]), GETJOCTET(data[13]));
656 totallen -= APP0_DATA_LEN;
657 if (totallen !=
658 ((INT32)GETJOCTET(data[12]) * (INT32)GETJOCTET(data[13]) * (INT32) 3))
659 TRACEMS1(cinfo, 1, JTRC_JFIF_BADTHUMBNAILSIZE, (int) totallen);
660 } else if (datalen >= 6 &&
661 GETJOCTET(data[0]) == 0x4A &&
662 GETJOCTET(data[1]) == 0x46 &&
663 GETJOCTET(data[2]) == 0x58 &&
664 GETJOCTET(data[3]) == 0x58 &&
665 GETJOCTET(data[4]) == 0) {
666 /* Found JFIF "JFXX" extension APP0 marker */
667 /* The library doesn't actually do anything with these,
668 * but we try to produce a helpful trace message.
669 */
670 switch (GETJOCTET(data[5])) {
671 case 0x10:
672 TRACEMS1(cinfo, 1, JTRC_THUMB_JPEG, (int) totallen);
673 break;
674 case 0x11:
675 TRACEMS1(cinfo, 1, JTRC_THUMB_PALETTE, (int) totallen);
676 break;
677 case 0x13:
678 TRACEMS1(cinfo, 1, JTRC_THUMB_RGB, (int) totallen);
679 break;
680 default:
681 TRACEMS2(cinfo, 1, JTRC_JFIF_EXTENSION,
682 GETJOCTET(data[5]), (int) totallen);
683 break;
684 }
685 } else {
686 /* Start of APP0 does not match "JFIF" or "JFXX", or too short */
687 TRACEMS1(cinfo, 1, JTRC_APP0, (int) totallen);
688 }
689 }
690
691
692 LOCAL(void)
examine_app14(j_decompress_ptr cinfo,JOCTET FAR * data,unsigned int datalen,INT32 remaining)693 examine_app14 (j_decompress_ptr cinfo, JOCTET FAR * data,
694 unsigned int datalen, INT32 remaining)
695 /* Examine first few bytes from an APP14.
696 * Take appropriate action if it is an Adobe marker.
697 * datalen is # of bytes at data[], remaining is length of rest of marker data.
698 */
699 {
700 unsigned int version, flags0, flags1, transform;
701
702 if (datalen >= APP14_DATA_LEN &&
703 GETJOCTET(data[0]) == 0x41 &&
704 GETJOCTET(data[1]) == 0x64 &&
705 GETJOCTET(data[2]) == 0x6F &&
706 GETJOCTET(data[3]) == 0x62 &&
707 GETJOCTET(data[4]) == 0x65) {
708 /* Found Adobe APP14 marker */
709 version = (GETJOCTET(data[5]) << 8) + GETJOCTET(data[6]);
710 flags0 = (GETJOCTET(data[7]) << 8) + GETJOCTET(data[8]);
711 flags1 = (GETJOCTET(data[9]) << 8) + GETJOCTET(data[10]);
712 transform = GETJOCTET(data[11]);
713 TRACEMS4(cinfo, 1, JTRC_ADOBE, version, flags0, flags1, transform);
714 cinfo->saw_Adobe_marker = TRUE;
715 cinfo->Adobe_transform = (UINT8) transform;
716 } else {
717 /* Start of APP14 does not match "Adobe", or too short */
718 TRACEMS1(cinfo, 1, JTRC_APP14, (int) (datalen + remaining));
719 }
720 }
721
722
723 METHODDEF(boolean)
get_interesting_appn(j_decompress_ptr cinfo)724 get_interesting_appn (j_decompress_ptr cinfo)
725 /* Process an APP0 or APP14 marker without saving it */
726 {
727 INT32 length;
728 JOCTET b[APPN_DATA_LEN];
729 unsigned int i, numtoread;
730 INPUT_VARS(cinfo);
731
732 INPUT_2BYTES(cinfo, length, return FALSE);
733 length -= 2;
734
735 /* get the interesting part of the marker data */
736 if (length >= APPN_DATA_LEN)
737 numtoread = APPN_DATA_LEN;
738 else if (length > 0)
739 numtoread = (unsigned int) length;
740 else
741 numtoread = 0;
742 for (i = 0; i < numtoread; i++)
743 INPUT_BYTE(cinfo, b[i], return FALSE);
744 length -= numtoread;
745
746 /* process it */
747 switch (cinfo->unread_marker) {
748 case M_APP0:
749 examine_app0(cinfo, (JOCTET FAR *) b, numtoread, length);
750 break;
751 case M_APP14:
752 examine_app14(cinfo, (JOCTET FAR *) b, numtoread, length);
753 break;
754 default:
755 /* can't get here unless jpeg_save_markers chooses wrong processor */
756 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
757 break;
758 }
759
760 /* skip any remaining data -- could be lots */
761 INPUT_SYNC(cinfo);
762 if (length > 0)
763 (*cinfo->src->skip_input_data) (cinfo, (long) length);
764
765 return TRUE;
766 }
767
768
769 #ifdef SAVE_MARKERS_SUPPORTED
770
771 METHODDEF(boolean)
save_marker(j_decompress_ptr cinfo)772 save_marker (j_decompress_ptr cinfo)
773 /* Save an APPn or COM marker into the marker list */
774 {
775 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
776 jpeg_saved_marker_ptr cur_marker = marker->cur_marker;
777 unsigned int bytes_read, data_length;
778 JOCTET FAR * data;
779 INT32 length = 0;
780 INPUT_VARS(cinfo);
781
782 if (cur_marker == NULL) {
783 /* begin reading a marker */
784 INPUT_2BYTES(cinfo, length, return FALSE);
785 length -= 2;
786 if (length >= 0) { /* watch out for bogus length word */
787 /* figure out how much we want to save */
788 unsigned int limit;
789 if (cinfo->unread_marker == (int) M_COM)
790 limit = marker->length_limit_COM;
791 else
792 limit = marker->length_limit_APPn[cinfo->unread_marker - (int) M_APP0];
793 if ((unsigned int) length < limit)
794 limit = (unsigned int) length;
795 /* allocate and initialize the marker item */
796 cur_marker = (jpeg_saved_marker_ptr)
797 (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
798 SIZEOF(struct jpeg_marker_struct) + limit);
799 cur_marker->next = NULL;
800 cur_marker->marker = (UINT8) cinfo->unread_marker;
801 cur_marker->original_length = (unsigned int) length;
802 cur_marker->data_length = limit;
803 /* data area is just beyond the jpeg_marker_struct */
804 data = cur_marker->data = (JOCTET FAR *) (cur_marker + 1);
805 marker->cur_marker = cur_marker;
806 marker->bytes_read = 0;
807 bytes_read = 0;
808 data_length = limit;
809 } else {
810 /* deal with bogus length word */
811 bytes_read = data_length = 0;
812 data = NULL;
813 }
814 } else {
815 /* resume reading a marker */
816 bytes_read = marker->bytes_read;
817 data_length = cur_marker->data_length;
818 data = cur_marker->data + bytes_read;
819 }
820
821 while (bytes_read < data_length) {
822 INPUT_SYNC(cinfo); /* move the restart point to here */
823 marker->bytes_read = bytes_read;
824 /* If there's not at least one byte in buffer, suspend */
825 MAKE_BYTE_AVAIL(cinfo, return FALSE);
826 /* Copy bytes with reasonable rapidity */
827 while (bytes_read < data_length && bytes_in_buffer > 0) {
828 *data++ = *next_input_byte++;
829 bytes_in_buffer--;
830 bytes_read++;
831 }
832 }
833
834 /* Done reading what we want to read */
835 if (cur_marker != NULL) { /* will be NULL if bogus length word */
836 /* Add new marker to end of list */
837 if (cinfo->marker_list == NULL) {
838 cinfo->marker_list = cur_marker;
839 } else {
840 jpeg_saved_marker_ptr prev = cinfo->marker_list;
841 while (prev->next != NULL)
842 prev = prev->next;
843 prev->next = cur_marker;
844 }
845 /* Reset pointer & calc remaining data length */
846 data = cur_marker->data;
847 length = cur_marker->original_length - data_length;
848 }
849 /* Reset to initial state for next marker */
850 marker->cur_marker = NULL;
851
852 /* Process the marker if interesting; else just make a generic trace msg */
853 switch (cinfo->unread_marker) {
854 case M_APP0:
855 examine_app0(cinfo, data, data_length, length);
856 break;
857 case M_APP14:
858 examine_app14(cinfo, data, data_length, length);
859 break;
860 default:
861 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker,
862 (int) (data_length + length));
863 break;
864 }
865
866 /* skip any remaining data -- could be lots */
867 INPUT_SYNC(cinfo); /* do before skip_input_data */
868 if (length > 0)
869 (*cinfo->src->skip_input_data) (cinfo, (long) length);
870
871 return TRUE;
872 }
873
874 #endif /* SAVE_MARKERS_SUPPORTED */
875
876
877 METHODDEF(boolean)
skip_variable(j_decompress_ptr cinfo)878 skip_variable (j_decompress_ptr cinfo)
879 /* Skip over an unknown or uninteresting variable-length marker */
880 {
881 INT32 length;
882 INPUT_VARS(cinfo);
883
884 INPUT_2BYTES(cinfo, length, return FALSE);
885 length -= 2;
886
887 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, (int) length);
888
889 INPUT_SYNC(cinfo); /* do before skip_input_data */
890 if (length > 0)
891 (*cinfo->src->skip_input_data) (cinfo, (long) length);
892
893 return TRUE;
894 }
895
896
897 /*
898 * Find the next JPEG marker, save it in cinfo->unread_marker.
899 * Returns FALSE if had to suspend before reaching a marker;
900 * in that case cinfo->unread_marker is unchanged.
901 *
902 * Note that the result might not be a valid marker code,
903 * but it will never be 0 or FF.
904 */
905
906 LOCAL(boolean)
next_marker(j_decompress_ptr cinfo)907 next_marker (j_decompress_ptr cinfo)
908 {
909 int c;
910 INPUT_VARS(cinfo);
911
912 for (;;) {
913 INPUT_BYTE(cinfo, c, return FALSE);
914 /* Skip any non-FF bytes.
915 * This may look a bit inefficient, but it will not occur in a valid file.
916 * We sync after each discarded byte so that a suspending data source
917 * can discard the byte from its buffer.
918 */
919 while (c != 0xFF) {
920 cinfo->marker->discarded_bytes++;
921 INPUT_SYNC(cinfo);
922 INPUT_BYTE(cinfo, c, return FALSE);
923 }
924 /* This loop swallows any duplicate FF bytes. Extra FFs are legal as
925 * pad bytes, so don't count them in discarded_bytes. We assume there
926 * will not be so many consecutive FF bytes as to overflow a suspending
927 * data source's input buffer.
928 */
929 do {
930 INPUT_BYTE(cinfo, c, return FALSE);
931 } while (c == 0xFF);
932 if (c != 0)
933 break; /* found a valid marker, exit loop */
934 /* Reach here if we found a stuffed-zero data sequence (FF/00).
935 * Discard it and loop back to try again.
936 */
937 cinfo->marker->discarded_bytes += 2;
938 INPUT_SYNC(cinfo);
939 }
940
941 if (cinfo->marker->discarded_bytes != 0) {
942 WARNMS2(cinfo, JWRN_EXTRANEOUS_DATA, cinfo->marker->discarded_bytes, c);
943 cinfo->marker->discarded_bytes = 0;
944 }
945
946 cinfo->unread_marker = c;
947
948 INPUT_SYNC(cinfo);
949 return TRUE;
950 }
951
952
953 LOCAL(boolean)
first_marker(j_decompress_ptr cinfo)954 first_marker (j_decompress_ptr cinfo)
955 /* Like next_marker, but used to obtain the initial SOI marker. */
956 /* For this marker, we do not allow preceding garbage or fill; otherwise,
957 * we might well scan an entire input file before realizing it ain't JPEG.
958 * If an application wants to process non-JFIF files, it must seek to the
959 * SOI before calling the JPEG library.
960 */
961 {
962 int c, c2;
963 INPUT_VARS(cinfo);
964
965 INPUT_BYTE(cinfo, c, return FALSE);
966 INPUT_BYTE(cinfo, c2, return FALSE);
967 if (c != 0xFF || c2 != (int) M_SOI)
968 ERREXIT2(cinfo, JERR_NO_SOI, c, c2);
969
970 cinfo->unread_marker = c2;
971
972 INPUT_SYNC(cinfo);
973 return TRUE;
974 }
975
976
977 /*
978 * Read markers until SOS or EOI.
979 *
980 * Returns same codes as are defined for jpeg_consume_input:
981 * JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
982 */
983
984 METHODDEF(int)
read_markers(j_decompress_ptr cinfo)985 read_markers (j_decompress_ptr cinfo)
986 {
987 /* Outer loop repeats once for each marker. */
988 for (;;) {
989 /* Collect the marker proper, unless we already did. */
990 /* NB: first_marker() enforces the requirement that SOI appear first. */
991 if (cinfo->unread_marker == 0) {
992 if (! cinfo->marker->saw_SOI) {
993 if (! first_marker(cinfo))
994 return JPEG_SUSPENDED;
995 } else {
996 if (! next_marker(cinfo))
997 return JPEG_SUSPENDED;
998 }
999 }
1000 /* At this point cinfo->unread_marker contains the marker code and the
1001 * input point is just past the marker proper, but before any parameters.
1002 * A suspension will cause us to return with this state still true.
1003 */
1004 switch (cinfo->unread_marker) {
1005 case M_SOI:
1006 if (! get_soi(cinfo))
1007 return JPEG_SUSPENDED;
1008 break;
1009
1010 case M_SOF0: /* Baseline */
1011 case M_SOF1: /* Extended sequential, Huffman */
1012 if (! get_sof(cinfo, FALSE, FALSE))
1013 return JPEG_SUSPENDED;
1014 break;
1015
1016 case M_SOF2: /* Progressive, Huffman */
1017 if (! get_sof(cinfo, TRUE, FALSE))
1018 return JPEG_SUSPENDED;
1019 break;
1020
1021 case M_SOF9: /* Extended sequential, arithmetic */
1022 if (! get_sof(cinfo, FALSE, TRUE))
1023 return JPEG_SUSPENDED;
1024 break;
1025
1026 case M_SOF10: /* Progressive, arithmetic */
1027 if (! get_sof(cinfo, TRUE, TRUE))
1028 return JPEG_SUSPENDED;
1029 break;
1030
1031 /* Currently unsupported SOFn types */
1032 case M_SOF3: /* Lossless, Huffman */
1033 case M_SOF5: /* Differential sequential, Huffman */
1034 case M_SOF6: /* Differential progressive, Huffman */
1035 case M_SOF7: /* Differential lossless, Huffman */
1036 case M_JPG: /* Reserved for JPEG extensions */
1037 case M_SOF11: /* Lossless, arithmetic */
1038 case M_SOF13: /* Differential sequential, arithmetic */
1039 case M_SOF14: /* Differential progressive, arithmetic */
1040 case M_SOF15: /* Differential lossless, arithmetic */
1041 ERREXIT1(cinfo, JERR_SOF_UNSUPPORTED, cinfo->unread_marker);
1042 break;
1043
1044 case M_SOS:
1045 if (! get_sos(cinfo))
1046 return JPEG_SUSPENDED;
1047 cinfo->unread_marker = 0; /* processed the marker */
1048 return JPEG_REACHED_SOS;
1049
1050 case M_EOI:
1051 TRACEMS(cinfo, 1, JTRC_EOI);
1052 cinfo->unread_marker = 0; /* processed the marker */
1053 return JPEG_REACHED_EOI;
1054
1055 case M_DAC:
1056 if (! get_dac(cinfo))
1057 return JPEG_SUSPENDED;
1058 break;
1059
1060 case M_DHT:
1061 if (! get_dht(cinfo))
1062 return JPEG_SUSPENDED;
1063 break;
1064
1065 case M_DQT:
1066 if (! get_dqt(cinfo))
1067 return JPEG_SUSPENDED;
1068 break;
1069
1070 case M_DRI:
1071 if (! get_dri(cinfo))
1072 return JPEG_SUSPENDED;
1073 break;
1074
1075 case M_APP0:
1076 case M_APP1:
1077 case M_APP2:
1078 case M_APP3:
1079 case M_APP4:
1080 case M_APP5:
1081 case M_APP6:
1082 case M_APP7:
1083 case M_APP8:
1084 case M_APP9:
1085 case M_APP10:
1086 case M_APP11:
1087 case M_APP12:
1088 case M_APP13:
1089 case M_APP14:
1090 case M_APP15:
1091 if (! (*((my_marker_ptr) cinfo->marker)->process_APPn[
1092 cinfo->unread_marker - (int) M_APP0]) (cinfo))
1093 return JPEG_SUSPENDED;
1094 break;
1095
1096 case M_COM:
1097 if (! (*((my_marker_ptr) cinfo->marker)->process_COM) (cinfo))
1098 return JPEG_SUSPENDED;
1099 break;
1100
1101 case M_RST0: /* these are all parameterless */
1102 case M_RST1:
1103 case M_RST2:
1104 case M_RST3:
1105 case M_RST4:
1106 case M_RST5:
1107 case M_RST6:
1108 case M_RST7:
1109 case M_TEM:
1110 TRACEMS1(cinfo, 1, JTRC_PARMLESS_MARKER, cinfo->unread_marker);
1111 break;
1112
1113 case M_DNL: /* Ignore DNL ... perhaps the wrong thing */
1114 if (! skip_variable(cinfo))
1115 return JPEG_SUSPENDED;
1116 break;
1117
1118 default: /* must be DHP, EXP, JPGn, or RESn */
1119 /* For now, we treat the reserved markers as fatal errors since they are
1120 * likely to be used to signal incompatible JPEG Part 3 extensions.
1121 * Once the JPEG 3 version-number marker is well defined, this code
1122 * ought to change!
1123 */
1124 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
1125 break;
1126 }
1127 /* Successfully processed marker, so reset state variable */
1128 cinfo->unread_marker = 0;
1129 } /* end loop */
1130 }
1131
1132
1133 /*
1134 * Read a restart marker, which is expected to appear next in the datastream;
1135 * if the marker is not there, take appropriate recovery action.
1136 * Returns FALSE if suspension is required.
1137 *
1138 * This is called by the entropy decoder after it has read an appropriate
1139 * number of MCUs. cinfo->unread_marker may be nonzero if the entropy decoder
1140 * has already read a marker from the data source. Under normal conditions
1141 * cinfo->unread_marker will be reset to 0 before returning; if not reset,
1142 * it holds a marker which the decoder will be unable to read past.
1143 */
1144
1145 METHODDEF(boolean)
read_restart_marker(j_decompress_ptr cinfo)1146 read_restart_marker (j_decompress_ptr cinfo)
1147 {
1148 /* Obtain a marker unless we already did. */
1149 /* Note that next_marker will complain if it skips any data. */
1150 if (cinfo->unread_marker == 0) {
1151 if (! next_marker(cinfo))
1152 return FALSE;
1153 }
1154
1155 if (cinfo->unread_marker ==
1156 ((int) M_RST0 + cinfo->marker->next_restart_num)) {
1157 /* Normal case --- swallow the marker and let entropy decoder continue */
1158 TRACEMS1(cinfo, 3, JTRC_RST, cinfo->marker->next_restart_num);
1159 cinfo->unread_marker = 0;
1160 } else {
1161 /* Uh-oh, the restart markers have been messed up. */
1162 /* Let the data source manager determine how to resync. */
1163 if (! (*cinfo->src->resync_to_restart) (cinfo,
1164 cinfo->marker->next_restart_num))
1165 return FALSE;
1166 }
1167
1168 /* Update next-restart state */
1169 cinfo->marker->next_restart_num = (cinfo->marker->next_restart_num + 1) & 7;
1170
1171 return TRUE;
1172 }
1173
1174
1175 /*
1176 * This is the default resync_to_restart method for data source managers
1177 * to use if they don't have any better approach. Some data source managers
1178 * may be able to back up, or may have additional knowledge about the data
1179 * which permits a more intelligent recovery strategy; such managers would
1180 * presumably supply their own resync method.
1181 *
1182 * read_restart_marker calls resync_to_restart if it finds a marker other than
1183 * the restart marker it was expecting. (This code is *not* used unless
1184 * a nonzero restart interval has been declared.) cinfo->unread_marker is
1185 * the marker code actually found (might be anything, except 0 or FF).
1186 * The desired restart marker number (0..7) is passed as a parameter.
1187 * This routine is supposed to apply whatever error recovery strategy seems
1188 * appropriate in order to position the input stream to the next data segment.
1189 * Note that cinfo->unread_marker is treated as a marker appearing before
1190 * the current data-source input point; usually it should be reset to zero
1191 * before returning.
1192 * Returns FALSE if suspension is required.
1193 *
1194 * This implementation is substantially constrained by wanting to treat the
1195 * input as a data stream; this means we can't back up. Therefore, we have
1196 * only the following actions to work with:
1197 * 1. Simply discard the marker and let the entropy decoder resume at next
1198 * byte of file.
1199 * 2. Read forward until we find another marker, discarding intervening
1200 * data. (In theory we could look ahead within the current bufferload,
1201 * without having to discard data if we don't find the desired marker.
1202 * This idea is not implemented here, in part because it makes behavior
1203 * dependent on buffer size and chance buffer-boundary positions.)
1204 * 3. Leave the marker unread (by failing to zero cinfo->unread_marker).
1205 * This will cause the entropy decoder to process an empty data segment,
1206 * inserting dummy zeroes, and then we will reprocess the marker.
1207 *
1208 * #2 is appropriate if we think the desired marker lies ahead, while #3 is
1209 * appropriate if the found marker is a future restart marker (indicating
1210 * that we have missed the desired restart marker, probably because it got
1211 * corrupted).
1212 * We apply #2 or #3 if the found marker is a restart marker no more than
1213 * two counts behind or ahead of the expected one. We also apply #2 if the
1214 * found marker is not a legal JPEG marker code (it's certainly bogus data).
1215 * If the found marker is a restart marker more than 2 counts away, we do #1
1216 * (too much risk that the marker is erroneous; with luck we will be able to
1217 * resync at some future point).
1218 * For any valid non-restart JPEG marker, we apply #3. This keeps us from
1219 * overrunning the end of a scan. An implementation limited to single-scan
1220 * files might find it better to apply #2 for markers other than EOI, since
1221 * any other marker would have to be bogus data in that case.
1222 */
1223
1224 GLOBAL(boolean)
jpeg_resync_to_restart(j_decompress_ptr cinfo,int desired)1225 jpeg_resync_to_restart (j_decompress_ptr cinfo, int desired)
1226 {
1227 int marker = cinfo->unread_marker;
1228 int action = 1;
1229
1230 /* Always put up a warning. */
1231 WARNMS2(cinfo, JWRN_MUST_RESYNC, marker, desired);
1232
1233 /* Outer loop handles repeated decision after scanning forward. */
1234 for (;;) {
1235 if (marker < (int) M_SOF0)
1236 action = 2; /* invalid marker */
1237 else if (marker < (int) M_RST0 || marker > (int) M_RST7)
1238 action = 3; /* valid non-restart marker */
1239 else {
1240 if (marker == ((int) M_RST0 + ((desired+1) & 7)) ||
1241 marker == ((int) M_RST0 + ((desired+2) & 7)))
1242 action = 3; /* one of the next two expected restarts */
1243 else if (marker == ((int) M_RST0 + ((desired-1) & 7)) ||
1244 marker == ((int) M_RST0 + ((desired-2) & 7)))
1245 action = 2; /* a prior restart, so advance */
1246 else
1247 action = 1; /* desired restart or too far away */
1248 }
1249 TRACEMS2(cinfo, 4, JTRC_RECOVERY_ACTION, marker, action);
1250 switch (action) {
1251 case 1:
1252 /* Discard marker and let entropy decoder resume processing. */
1253 cinfo->unread_marker = 0;
1254 return TRUE;
1255 case 2:
1256 /* Scan to the next marker, and repeat the decision loop. */
1257 if (! next_marker(cinfo))
1258 return FALSE;
1259 marker = cinfo->unread_marker;
1260 break;
1261 case 3:
1262 /* Return without advancing past this marker. */
1263 /* Entropy decoder will be forced to process an empty segment. */
1264 return TRUE;
1265 }
1266 } /* end loop */
1267 }
1268
1269
1270 /*
1271 * Reset marker processing state to begin a fresh datastream.
1272 */
1273
1274 METHODDEF(void)
reset_marker_reader(j_decompress_ptr cinfo)1275 reset_marker_reader (j_decompress_ptr cinfo)
1276 {
1277 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1278
1279 cinfo->comp_info = NULL; /* until allocated by get_sof */
1280 cinfo->input_scan_number = 0; /* no SOS seen yet */
1281 cinfo->unread_marker = 0; /* no pending marker */
1282 marker->pub.saw_SOI = FALSE; /* set internal state too */
1283 marker->pub.saw_SOF = FALSE;
1284 marker->pub.discarded_bytes = 0;
1285 marker->cur_marker = NULL;
1286 }
1287
1288
1289 /*
1290 * Initialize the marker reader module.
1291 * This is called only once, when the decompression object is created.
1292 */
1293
1294 GLOBAL(void)
jinit_marker_reader(j_decompress_ptr cinfo)1295 jinit_marker_reader (j_decompress_ptr cinfo)
1296 {
1297 my_marker_ptr marker;
1298 int i;
1299
1300 /* Create subobject in permanent pool */
1301 marker = (my_marker_ptr)
1302 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
1303 SIZEOF(my_marker_reader));
1304 cinfo->marker = (struct jpeg_marker_reader *) marker;
1305 /* Initialize public method pointers */
1306 marker->pub.reset_marker_reader = reset_marker_reader;
1307 marker->pub.read_markers = read_markers;
1308 marker->pub.read_restart_marker = read_restart_marker;
1309 /* Initialize COM/APPn processing.
1310 * By default, we examine and then discard APP0 and APP14,
1311 * but simply discard COM and all other APPn.
1312 */
1313 marker->process_COM = skip_variable;
1314 marker->length_limit_COM = 0;
1315 for (i = 0; i < 16; i++) {
1316 marker->process_APPn[i] = skip_variable;
1317 marker->length_limit_APPn[i] = 0;
1318 }
1319 marker->process_APPn[0] = get_interesting_appn;
1320 marker->process_APPn[14] = get_interesting_appn;
1321 /* Reset marker processing state */
1322 reset_marker_reader(cinfo);
1323 }
1324
1325
1326 /*
1327 * Control saving of COM and APPn markers into marker_list.
1328 */
1329
1330 #ifdef SAVE_MARKERS_SUPPORTED
1331
1332 GLOBAL(void)
jpeg_save_markers(j_decompress_ptr cinfo,int marker_code,unsigned int length_limit)1333 jpeg_save_markers (j_decompress_ptr cinfo, int marker_code,
1334 unsigned int length_limit)
1335 {
1336 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1337 long maxlength;
1338 jpeg_marker_parser_method processor;
1339
1340 /* Length limit mustn't be larger than what we can allocate
1341 * (should only be a concern in a 16-bit environment).
1342 */
1343 maxlength = cinfo->mem->max_alloc_chunk - SIZEOF(struct jpeg_marker_struct);
1344 if (((long) length_limit) > maxlength)
1345 length_limit = (unsigned int) maxlength;
1346
1347 /* Choose processor routine to use.
1348 * APP0/APP14 have special requirements.
1349 */
1350 if (length_limit) {
1351 processor = save_marker;
1352 /* If saving APP0/APP14, save at least enough for our internal use. */
1353 if (marker_code == (int) M_APP0 && length_limit < APP0_DATA_LEN)
1354 length_limit = APP0_DATA_LEN;
1355 else if (marker_code == (int) M_APP14 && length_limit < APP14_DATA_LEN)
1356 length_limit = APP14_DATA_LEN;
1357 } else {
1358 processor = skip_variable;
1359 /* If discarding APP0/APP14, use our regular on-the-fly processor. */
1360 if (marker_code == (int) M_APP0 || marker_code == (int) M_APP14)
1361 processor = get_interesting_appn;
1362 }
1363
1364 if (marker_code == (int) M_COM) {
1365 marker->process_COM = processor;
1366 marker->length_limit_COM = length_limit;
1367 } else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15) {
1368 marker->process_APPn[marker_code - (int) M_APP0] = processor;
1369 marker->length_limit_APPn[marker_code - (int) M_APP0] = length_limit;
1370 } else
1371 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
1372 }
1373
1374 #endif /* SAVE_MARKERS_SUPPORTED */
1375
1376
1377 /*
1378 * Install a special processing method for COM or APPn markers.
1379 */
1380
1381 GLOBAL(void)
jpeg_set_marker_processor(j_decompress_ptr cinfo,int marker_code,jpeg_marker_parser_method routine)1382 jpeg_set_marker_processor (j_decompress_ptr cinfo, int marker_code,
1383 jpeg_marker_parser_method routine)
1384 {
1385 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1386
1387 if (marker_code == (int) M_COM)
1388 marker->process_COM = routine;
1389 else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15)
1390 marker->process_APPn[marker_code - (int) M_APP0] = routine;
1391 else
1392 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
1393 }
1394