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 "jinclude8.h"
17 #include "jpeglib8.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 IJG_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,J_CODEC_PROCESS process,boolean is_arith,int data_unit)237 get_sof (j_decompress_ptr cinfo, J_CODEC_PROCESS process, boolean is_arith,
238 int data_unit)
239 /* Process a SOFn marker */
240 {
241 IJG_INT32 length;
242 int c, ci;
243 jpeg_component_info * compptr;
244 INPUT_VARS(cinfo);
245
246 cinfo->data_unit = data_unit;
247 cinfo->process = process;
248 cinfo->arith_code = is_arith;
249
250 INPUT_2BYTES(cinfo, length, return FALSE);
251
252 INPUT_BYTE(cinfo, cinfo->data_precision, return FALSE);
253 INPUT_2BYTES(cinfo, cinfo->image_height, return FALSE);
254 INPUT_2BYTES(cinfo, cinfo->image_width, return FALSE);
255 INPUT_BYTE(cinfo, cinfo->num_components, return FALSE);
256
257 length -= 8;
258
259 TRACEMS4(cinfo, 1, JTRC_SOF, cinfo->unread_marker,
260 (int) cinfo->image_width, (int) cinfo->image_height,
261 cinfo->num_components);
262
263 if (cinfo->marker->saw_SOF)
264 ERREXIT(cinfo, JERR_SOF_DUPLICATE);
265
266 /* We don't support files in which the image height is initially specified */
267 /* as 0 and is later redefined by DNL. As long as we have to check that, */
268 /* might as well have a general sanity check. */
269 if (cinfo->image_height <= 0 || cinfo->image_width <= 0
270 || cinfo->num_components <= 0)
271 ERREXIT(cinfo, JERR_EMPTY_IMAGE);
272
273 if (length != (cinfo->num_components * 3))
274 ERREXIT(cinfo, JERR_BAD_LENGTH);
275
276 if (cinfo->comp_info == NULL) /* do only once, even if suspend */
277 cinfo->comp_info = (jpeg_component_info *) (*cinfo->mem->alloc_small)
278 ((j_common_ptr) cinfo, JPOOL_IMAGE,
279 (size_t)cinfo->num_components * SIZEOF(jpeg_component_info));
280
281 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
282 ci++, compptr++) {
283 compptr->component_index = ci;
284 INPUT_BYTE(cinfo, compptr->component_id, return FALSE);
285 INPUT_BYTE(cinfo, c, return FALSE);
286 compptr->h_samp_factor = (c >> 4) & 15;
287 compptr->v_samp_factor = (c ) & 15;
288 INPUT_BYTE(cinfo, compptr->quant_tbl_no, return FALSE);
289
290 TRACEMS4(cinfo, 1, JTRC_SOF_COMPONENT,
291 compptr->component_id, compptr->h_samp_factor,
292 compptr->v_samp_factor, compptr->quant_tbl_no);
293 }
294
295 cinfo->marker->saw_SOF = TRUE;
296
297 INPUT_SYNC(cinfo);
298 return TRUE;
299 }
300
301
302 LOCAL(boolean)
get_sos(j_decompress_ptr cinfo)303 get_sos (j_decompress_ptr cinfo)
304 /* Process a SOS marker */
305 {
306 IJG_INT32 length;
307 int i, ci, n, c, cc;
308 jpeg_component_info * compptr;
309 INPUT_VARS(cinfo);
310
311 if (! cinfo->marker->saw_SOF)
312 ERREXIT(cinfo, JERR_SOS_NO_SOF);
313
314 INPUT_2BYTES(cinfo, length, return FALSE);
315
316 INPUT_BYTE(cinfo, n, return FALSE); /* Number of components */
317
318 TRACEMS1(cinfo, 1, JTRC_SOS, n);
319
320 if (length != (n * 2 + 6) || n < 1 || n > MAX_COMPS_IN_SCAN)
321 ERREXIT(cinfo, JERR_BAD_LENGTH);
322
323 cinfo->comps_in_scan = n;
324
325 /* Collect the component-spec parameters */
326
327 for (i = 0; i < n; i++) {
328 INPUT_BYTE(cinfo, cc, return FALSE);
329 INPUT_BYTE(cinfo, c, return FALSE);
330
331 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
332 ci++, compptr++) {
333 if (cc == compptr->component_id)
334 goto id_found;
335 }
336
337 ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc);
338
339 id_found:
340
341 cinfo->cur_comp_info[i] = compptr;
342 compptr->dc_tbl_no = (c >> 4) & 15;
343 compptr->ac_tbl_no = (c ) & 15;
344
345 TRACEMS3(cinfo, 1, JTRC_SOS_COMPONENT, cc,
346 compptr->dc_tbl_no, compptr->ac_tbl_no);
347 }
348
349 /* Collect the additional scan parameters Ss, Se, Ah/Al. */
350 INPUT_BYTE(cinfo, c, return FALSE);
351 cinfo->Ss = c;
352 INPUT_BYTE(cinfo, c, return FALSE);
353 cinfo->Se = c;
354 INPUT_BYTE(cinfo, c, return FALSE);
355 cinfo->Ah = (c >> 4) & 15;
356 cinfo->Al = (c ) & 15;
357
358 TRACEMS4(cinfo, 1, JTRC_SOS_PARAMS, cinfo->Ss, cinfo->Se,
359 cinfo->Ah, cinfo->Al);
360
361 /* Prepare to scan data & restart markers */
362 cinfo->marker->next_restart_num = 0;
363
364 /* Count another SOS marker */
365 cinfo->input_scan_number++;
366
367 INPUT_SYNC(cinfo);
368 return TRUE;
369 }
370
371
372 #ifdef D_ARITH_CODING_SUPPORTED
373
374 LOCAL(boolean)
get_dac(j_decompress_ptr cinfo)375 get_dac (j_decompress_ptr cinfo)
376 /* Process a DAC marker */
377 {
378 IJG_INT32 length;
379 int idx, val;
380 INPUT_VARS(cinfo);
381
382 INPUT_2BYTES(cinfo, length, return FALSE);
383 length -= 2;
384
385 while (length > 0) {
386 INPUT_BYTE(cinfo, idx, return FALSE);
387 INPUT_BYTE(cinfo, val, return FALSE);
388
389 length -= 2;
390
391 TRACEMS2(cinfo, 1, JTRC_DAC, idx, val);
392
393 if (idx < 0 || idx >= (2*NUM_ARITH_TBLS))
394 ERREXIT1(cinfo, JERR_DAC_INDEX, idx);
395
396 if (idx >= NUM_ARITH_TBLS) { /* define AC table */
397 cinfo->arith_ac_K[idx-NUM_ARITH_TBLS] = (UINT8) val;
398 } else { /* define DC table */
399 cinfo->arith_dc_L[idx] = (UINT8) (val & 0x0F);
400 cinfo->arith_dc_U[idx] = (UINT8) (val >> 4);
401 if (cinfo->arith_dc_L[idx] > cinfo->arith_dc_U[idx])
402 ERREXIT1(cinfo, JERR_DAC_VALUE, val);
403 }
404 }
405
406 if (length != 0)
407 ERREXIT(cinfo, JERR_BAD_LENGTH);
408
409 INPUT_SYNC(cinfo);
410 return TRUE;
411 }
412
413 #else /* ! D_ARITH_CODING_SUPPORTED */
414
415 #define get_dac(cinfo) skip_variable(cinfo)
416
417 #endif /* D_ARITH_CODING_SUPPORTED */
418
419
420 LOCAL(boolean)
get_dht(j_decompress_ptr cinfo)421 get_dht (j_decompress_ptr cinfo)
422 /* Process a DHT marker */
423 {
424 IJG_INT32 length;
425 UINT8 bits[17];
426 UINT8 huffval[256];
427 int i, idx, count;
428 JHUFF_TBL **htblptr;
429 INPUT_VARS(cinfo);
430
431 INPUT_2BYTES(cinfo, length, return FALSE);
432 length -= 2;
433
434 while (length > 16) {
435 INPUT_BYTE(cinfo, idx, return FALSE);
436
437 TRACEMS1(cinfo, 1, JTRC_DHT, idx);
438
439 bits[0] = 0;
440 count = 0;
441 for (i = 1; i <= 16; i++) {
442 INPUT_BYTE(cinfo, bits[i], return FALSE);
443 count += bits[i];
444 }
445
446 length -= 1 + 16;
447
448 TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
449 bits[1], bits[2], bits[3], bits[4],
450 bits[5], bits[6], bits[7], bits[8]);
451 TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
452 bits[9], bits[10], bits[11], bits[12],
453 bits[13], bits[14], bits[15], bits[16]);
454
455 /* Here we just do minimal validation of the counts to avoid walking
456 * off the end of our table space. jdhuff.c will check more carefully.
457 */
458 if (count > 256 || ((IJG_INT32) count) > length)
459 ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
460
461 for (i = 0; i < count; i++)
462 INPUT_BYTE(cinfo, huffval[i], return FALSE);
463
464 length -= count;
465
466 if (idx & 0x10) { /* AC table definition */
467 idx -= 0x10;
468 htblptr = &cinfo->ac_huff_tbl_ptrs[idx];
469 } else { /* DC table definition */
470 htblptr = &cinfo->dc_huff_tbl_ptrs[idx];
471 }
472
473 if (idx < 0 || idx >= NUM_HUFF_TBLS)
474 ERREXIT1(cinfo, JERR_DHT_INDEX, idx);
475
476 if (*htblptr == NULL)
477 *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
478
479 MEMCOPY((*htblptr)->bits, bits, SIZEOF((*htblptr)->bits));
480 MEMCOPY((*htblptr)->huffval, huffval, SIZEOF((*htblptr)->huffval));
481 }
482
483 if (length != 0)
484 ERREXIT(cinfo, JERR_BAD_LENGTH);
485
486 INPUT_SYNC(cinfo);
487 return TRUE;
488 }
489
490
491 LOCAL(boolean)
get_dqt(j_decompress_ptr cinfo)492 get_dqt (j_decompress_ptr cinfo)
493 /* Process a DQT marker */
494 {
495 IJG_INT32 length;
496 int n, i, prec;
497 unsigned int tmp;
498 JQUANT_TBL *quant_ptr;
499 INPUT_VARS(cinfo);
500
501 INPUT_2BYTES(cinfo, length, return FALSE);
502 length -= 2;
503
504 while (length > 0) {
505 INPUT_BYTE(cinfo, n, return FALSE);
506 prec = n >> 4;
507 n &= 0x0F;
508
509 TRACEMS2(cinfo, 1, JTRC_DQT, n, prec);
510
511 if (n >= NUM_QUANT_TBLS)
512 ERREXIT1(cinfo, JERR_DQT_INDEX, n);
513
514 if (cinfo->quant_tbl_ptrs[n] == NULL)
515 cinfo->quant_tbl_ptrs[n] = jpeg_alloc_quant_table((j_common_ptr) cinfo);
516 quant_ptr = cinfo->quant_tbl_ptrs[n];
517
518 for (i = 0; i < DCTSIZE2; i++) {
519 if (prec)
520 INPUT_2BYTES(cinfo, tmp, return FALSE);
521 else
522 INPUT_BYTE(cinfo, tmp, return FALSE);
523 /* We convert the zigzag-order table to natural array order. */
524 quant_ptr->quantval[jpeg_natural_order[i]] = (UINT16) tmp;
525 }
526
527 if (cinfo->err->trace_level >= 2) {
528 for (i = 0; i < DCTSIZE2; i += 8) {
529 TRACEMS8(cinfo, 2, JTRC_QUANTVALS,
530 quant_ptr->quantval[i], quant_ptr->quantval[i+1],
531 quant_ptr->quantval[i+2], quant_ptr->quantval[i+3],
532 quant_ptr->quantval[i+4], quant_ptr->quantval[i+5],
533 quant_ptr->quantval[i+6], quant_ptr->quantval[i+7]);
534 }
535 }
536
537 length -= DCTSIZE2+1;
538 if (prec) length -= DCTSIZE2;
539 }
540
541 if (length != 0)
542 ERREXIT(cinfo, JERR_BAD_LENGTH);
543
544 INPUT_SYNC(cinfo);
545 return TRUE;
546 }
547
548
549 LOCAL(boolean)
get_dri(j_decompress_ptr cinfo)550 get_dri (j_decompress_ptr cinfo)
551 /* Process a DRI marker */
552 {
553 IJG_INT32 length;
554 unsigned int tmp;
555 INPUT_VARS(cinfo);
556
557 INPUT_2BYTES(cinfo, length, return FALSE);
558
559 if (length != 4)
560 ERREXIT(cinfo, JERR_BAD_LENGTH);
561
562 INPUT_2BYTES(cinfo, tmp, return FALSE);
563
564 TRACEMS1(cinfo, 1, JTRC_DRI, (int)tmp);
565
566 cinfo->restart_interval = tmp;
567
568 INPUT_SYNC(cinfo);
569 return TRUE;
570 }
571
572
573 /*
574 * Routines for processing APPn and COM markers.
575 * These are either saved in memory or discarded, per application request.
576 * APP0 and APP14 are specially checked to see if they are
577 * JFIF and Adobe markers, respectively.
578 */
579
580 #define APP0_DATA_LEN 14 /* Length of interesting data in APP0 */
581 #define APP14_DATA_LEN 12 /* Length of interesting data in APP14 */
582 #define APPN_DATA_LEN 14 /* Must be the largest of the above!! */
583
584
585 LOCAL(void)
examine_app0(j_decompress_ptr cinfo,const JOCTET FAR * data,unsigned int datalen,IJG_INT32 remaining)586 examine_app0 (j_decompress_ptr cinfo, const JOCTET FAR * data,
587 unsigned int datalen, IJG_INT32 remaining)
588 /* Examine first few bytes from an APP0.
589 * Take appropriate action if it is a JFIF marker.
590 * datalen is # of bytes at data[], remaining is length of rest of marker data.
591 */
592 {
593 IJG_INT32 totallen = (IJG_INT32) datalen + remaining;
594
595 if (datalen >= APP0_DATA_LEN &&
596 GETJOCTET(data[0]) == 0x4A &&
597 GETJOCTET(data[1]) == 0x46 &&
598 GETJOCTET(data[2]) == 0x49 &&
599 GETJOCTET(data[3]) == 0x46 &&
600 GETJOCTET(data[4]) == 0) {
601 /* Found JFIF APP0 marker: save info */
602 cinfo->saw_JFIF_marker = TRUE;
603 cinfo->JFIF_major_version = GETJOCTET(data[5]);
604 cinfo->JFIF_minor_version = GETJOCTET(data[6]);
605 cinfo->density_unit = GETJOCTET(data[7]);
606 cinfo->X_density = (UINT16)((GETJOCTET(data[8]) << 8) + GETJOCTET(data[9]));
607 cinfo->Y_density = (UINT16)((GETJOCTET(data[10]) << 8) + GETJOCTET(data[11]));
608 /* Check version.
609 * Major version must be 1, anything else signals an incompatible change.
610 * (We used to treat this as an error, but now it's a nonfatal warning,
611 * because some bozo at Hijaak couldn't read the spec.)
612 * Minor version should be 0..2, but process anyway if newer.
613 */
614 if (cinfo->JFIF_major_version != 1)
615 WARNMS2(cinfo, JWRN_JFIF_MAJOR,
616 cinfo->JFIF_major_version, cinfo->JFIF_minor_version);
617 /* Generate trace messages */
618 TRACEMS5(cinfo, 1, JTRC_JFIF,
619 cinfo->JFIF_major_version, cinfo->JFIF_minor_version,
620 cinfo->X_density, cinfo->Y_density, cinfo->density_unit);
621 /* Validate thumbnail dimensions and issue appropriate messages */
622 if (GETJOCTET(data[12]) | GETJOCTET(data[13]))
623 TRACEMS2(cinfo, 1, JTRC_JFIF_THUMBNAIL,
624 GETJOCTET(data[12]), GETJOCTET(data[13]));
625 totallen -= APP0_DATA_LEN;
626 if (totallen !=
627 ((IJG_INT32)GETJOCTET(data[12]) * (IJG_INT32)GETJOCTET(data[13]) * (IJG_INT32) 3))
628 TRACEMS1(cinfo, 1, JTRC_JFIF_BADTHUMBNAILSIZE, (int) totallen);
629 } else if (datalen >= 6 &&
630 GETJOCTET(data[0]) == 0x4A &&
631 GETJOCTET(data[1]) == 0x46 &&
632 GETJOCTET(data[2]) == 0x58 &&
633 GETJOCTET(data[3]) == 0x58 &&
634 GETJOCTET(data[4]) == 0) {
635 /* Found JFIF "JFXX" extension APP0 marker */
636 /* The library doesn't actually do anything with these,
637 * but we try to produce a helpful trace message.
638 */
639 switch (GETJOCTET(data[5])) {
640 case 0x10:
641 TRACEMS1(cinfo, 1, JTRC_THUMB_JPEG, (int) totallen);
642 break;
643 case 0x11:
644 TRACEMS1(cinfo, 1, JTRC_THUMB_PALETTE, (int) totallen);
645 break;
646 case 0x13:
647 TRACEMS1(cinfo, 1, JTRC_THUMB_RGB, (int) totallen);
648 break;
649 default:
650 TRACEMS2(cinfo, 1, JTRC_JFIF_EXTENSION,
651 GETJOCTET(data[5]), (int) totallen);
652 break;
653 }
654 } else {
655 /* Start of APP0 does not match "JFIF" or "JFXX", or too short */
656 TRACEMS1(cinfo, 1, JTRC_APP0, (int) totallen);
657 }
658 }
659
660
661 LOCAL(void)
examine_app14(j_decompress_ptr cinfo,const JOCTET FAR * data,unsigned int datalen,IJG_INT32 remaining)662 examine_app14 (j_decompress_ptr cinfo, const JOCTET FAR * data,
663 unsigned int datalen, IJG_INT32 remaining)
664 /* Examine first few bytes from an APP14.
665 * Take appropriate action if it is an Adobe marker.
666 * datalen is # of bytes at data[], remaining is length of rest of marker data.
667 */
668 {
669 unsigned int version, flags0, flags1, transform;
670
671 if (datalen >= APP14_DATA_LEN &&
672 GETJOCTET(data[0]) == 0x41 &&
673 GETJOCTET(data[1]) == 0x64 &&
674 GETJOCTET(data[2]) == 0x6F &&
675 GETJOCTET(data[3]) == 0x62 &&
676 GETJOCTET(data[4]) == 0x65) {
677 /* Found Adobe APP14 marker */
678 version = (unsigned int)((GETJOCTET(data[5]) << 8) + GETJOCTET(data[6]));
679 flags0 = (unsigned int)((GETJOCTET(data[7]) << 8) + GETJOCTET(data[8]));
680 flags1 = (unsigned int)((GETJOCTET(data[9]) << 8) + GETJOCTET(data[10]));
681 transform = GETJOCTET(data[11]);
682 TRACEMS4(cinfo, 1, JTRC_ADOBE, (int)version, (int)flags0, (int)flags1, (int)transform);
683 cinfo->saw_Adobe_marker = TRUE;
684 cinfo->Adobe_transform = (UINT8) transform;
685 } else {
686 /* Start of APP14 does not match "Adobe", or too short */
687 TRACEMS1(cinfo, 1, JTRC_APP14, (int) (datalen + remaining));
688 }
689 }
690
691
692 METHODDEF(boolean)
get_interesting_appn(j_decompress_ptr cinfo)693 get_interesting_appn (j_decompress_ptr cinfo)
694 /* Process an APP0 or APP14 marker without saving it */
695 {
696 IJG_INT32 length;
697 JOCTET b[APPN_DATA_LEN];
698 unsigned int i, numtoread;
699 INPUT_VARS(cinfo);
700
701 INPUT_2BYTES(cinfo, length, return FALSE);
702 length -= 2;
703
704 /* get the interesting part of the marker data */
705 if (length >= APPN_DATA_LEN)
706 numtoread = APPN_DATA_LEN;
707 else if (length > 0)
708 numtoread = (unsigned int) length;
709 else
710 numtoread = 0;
711 for (i = 0; i < numtoread; i++)
712 INPUT_BYTE(cinfo, b[i], return FALSE);
713 length -= numtoread;
714
715 /* process it */
716 switch (cinfo->unread_marker) {
717 case M_APP0:
718 examine_app0(cinfo, (JOCTET FAR *) b, numtoread, length);
719 break;
720 case M_APP14:
721 examine_app14(cinfo, (JOCTET FAR *) b, numtoread, length);
722 break;
723 default:
724 /* can't get here unless jpeg_save_markers chooses wrong processor */
725 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
726 break;
727 }
728
729 /* skip any remaining data -- could be lots */
730 INPUT_SYNC(cinfo);
731 if (length > 0)
732 (*cinfo->src->skip_input_data) (cinfo, (long) length);
733
734 return TRUE;
735 }
736
737
738 #ifdef SAVE_MARKERS_SUPPORTED
739
740 METHODDEF(boolean)
save_marker(j_decompress_ptr cinfo)741 save_marker (j_decompress_ptr cinfo)
742 /* Save an APPn or COM marker into the marker list */
743 {
744 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
745 jpeg_saved_marker_ptr cur_marker = marker->cur_marker;
746 unsigned int bytes_read, data_length;
747 JOCTET FAR * data;
748 IJG_INT32 length = 0;
749 INPUT_VARS(cinfo);
750
751 if (cur_marker == NULL) {
752 /* begin reading a marker */
753 INPUT_2BYTES(cinfo, length, return FALSE);
754 length -= 2;
755 if (length >= 0) { /* watch out for bogus length word */
756 /* figure out how much we want to save */
757 unsigned int limit;
758 if (cinfo->unread_marker == (int) M_COM)
759 limit = marker->length_limit_COM;
760 else
761 limit = marker->length_limit_APPn[cinfo->unread_marker - (int) M_APP0];
762 if ((unsigned int) length < limit)
763 limit = (unsigned int) length;
764 /* allocate and initialize the marker item */
765 cur_marker = (jpeg_saved_marker_ptr)
766 (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
767 SIZEOF(struct jpeg_marker_struct) + limit);
768 cur_marker->next = NULL;
769 cur_marker->marker = (UINT8) cinfo->unread_marker;
770 cur_marker->original_length = (unsigned int) length;
771 cur_marker->data_length = limit;
772 /* data area is just beyond the jpeg_marker_struct */
773 data = cur_marker->data = (JOCTET FAR *) (cur_marker + 1);
774 marker->cur_marker = cur_marker;
775 marker->bytes_read = 0;
776 bytes_read = 0;
777 data_length = limit;
778 } else {
779 /* deal with bogus length word */
780 bytes_read = data_length = 0;
781 data = NULL;
782 }
783 } else {
784 /* resume reading a marker */
785 bytes_read = marker->bytes_read;
786 data_length = cur_marker->data_length;
787 data = cur_marker->data + bytes_read;
788 }
789
790 while (bytes_read < data_length) {
791 INPUT_SYNC(cinfo); /* move the restart point to here */
792 marker->bytes_read = bytes_read;
793 /* If there's not at least one byte in buffer, suspend */
794 MAKE_BYTE_AVAIL(cinfo, return FALSE);
795 /* Copy bytes with reasonable rapidity */
796 while (bytes_read < data_length && bytes_in_buffer > 0) {
797 *data++ = *next_input_byte++;
798 bytes_in_buffer--;
799 bytes_read++;
800 }
801 }
802
803 /* Done reading what we want to read */
804 if (cur_marker != NULL) { /* will be NULL if bogus length word */
805 /* Add new marker to end of list */
806 if (cinfo->marker_list == NULL) {
807 cinfo->marker_list = cur_marker;
808 } else {
809 jpeg_saved_marker_ptr prev = cinfo->marker_list;
810 while (prev->next != NULL)
811 prev = prev->next;
812 prev->next = cur_marker;
813 }
814 /* Reset pointer & calc remaining data length */
815 data = cur_marker->data;
816 length = cur_marker->original_length - data_length;
817 }
818 /* Reset to initial state for next marker */
819 marker->cur_marker = NULL;
820
821 /* Process the marker if interesting; else just make a generic trace msg */
822 switch (cinfo->unread_marker) {
823 case M_APP0:
824 examine_app0(cinfo, data, data_length, length);
825 break;
826 case M_APP14:
827 examine_app14(cinfo, data, data_length, length);
828 break;
829 default:
830 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker,
831 (int) (data_length + length));
832 break;
833 }
834
835 /* skip any remaining data -- could be lots */
836 INPUT_SYNC(cinfo); /* do before skip_input_data */
837 if (length > 0)
838 (*cinfo->src->skip_input_data) (cinfo, (long) length);
839
840 return TRUE;
841 }
842
843 #endif /* SAVE_MARKERS_SUPPORTED */
844
845
846 METHODDEF(boolean)
skip_variable(j_decompress_ptr cinfo)847 skip_variable (j_decompress_ptr cinfo)
848 /* Skip over an unknown or uninteresting variable-length marker */
849 {
850 IJG_INT32 length;
851 INPUT_VARS(cinfo);
852
853 INPUT_2BYTES(cinfo, length, return FALSE);
854 length -= 2;
855
856 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, (int) length);
857
858 INPUT_SYNC(cinfo); /* do before skip_input_data */
859 if (length > 0)
860 (*cinfo->src->skip_input_data) (cinfo, (long) length);
861
862 return TRUE;
863 }
864
865
866 /*
867 * Find the next JPEG marker, save it in cinfo->unread_marker.
868 * Returns FALSE if had to suspend before reaching a marker;
869 * in that case cinfo->unread_marker is unchanged.
870 *
871 * Note that the result might not be a valid marker code,
872 * but it will never be 0 or FF.
873 */
874
875 LOCAL(boolean)
next_marker(j_decompress_ptr cinfo)876 next_marker (j_decompress_ptr cinfo)
877 {
878 int c;
879 INPUT_VARS(cinfo);
880
881 for (;;) {
882 INPUT_BYTE(cinfo, c, return FALSE);
883 /* Skip any non-FF bytes.
884 * This may look a bit inefficient, but it will not occur in a valid file.
885 * We sync after each discarded byte so that a suspending data source
886 * can discard the byte from its buffer.
887 */
888 while (c != 0xFF) {
889 cinfo->marker->discarded_bytes++;
890 INPUT_SYNC(cinfo);
891 INPUT_BYTE(cinfo, c, return FALSE);
892 }
893 /* This loop swallows any duplicate FF bytes. Extra FFs are legal as
894 * pad bytes, so don't count them in discarded_bytes. We assume there
895 * will not be so many consecutive FF bytes as to overflow a suspending
896 * data source's input buffer.
897 */
898 do {
899 INPUT_BYTE(cinfo, c, return FALSE);
900 } while (c == 0xFF);
901 if (c != 0)
902 break; /* found a valid marker, exit loop */
903 /* Reach here if we found a stuffed-zero data sequence (FF/00).
904 * Discard it and loop back to try again.
905 */
906 cinfo->marker->discarded_bytes += 2;
907 INPUT_SYNC(cinfo);
908 }
909
910 if (cinfo->marker->discarded_bytes != 0) {
911 WARNMS2(cinfo, JWRN_EXTRANEOUS_DATA, (int)cinfo->marker->discarded_bytes, c);
912 cinfo->marker->discarded_bytes = 0;
913 }
914
915 cinfo->unread_marker = c;
916
917 INPUT_SYNC(cinfo);
918 return TRUE;
919 }
920
921
922 LOCAL(boolean)
first_marker(j_decompress_ptr cinfo)923 first_marker (j_decompress_ptr cinfo)
924 /* Like next_marker, but used to obtain the initial SOI marker. */
925 /* For this marker, we do not allow preceding garbage or fill; otherwise,
926 * we might well scan an entire input file before realizing it ain't JPEG.
927 * If an application wants to process non-JFIF files, it must seek to the
928 * SOI before calling the JPEG library.
929 */
930 {
931 int c, c2;
932 INPUT_VARS(cinfo);
933
934 INPUT_BYTE(cinfo, c, return FALSE);
935 INPUT_BYTE(cinfo, c2, return FALSE);
936 if (c != 0xFF || c2 != (int) M_SOI)
937 ERREXIT2(cinfo, JERR_NO_SOI, c, c2);
938
939 cinfo->unread_marker = c2;
940
941 INPUT_SYNC(cinfo);
942 return TRUE;
943 }
944
945
946 /*
947 * Read markers until SOS or EOI.
948 *
949 * Returns same codes as are defined for jpeg_consume_input:
950 * JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
951 */
952
953 METHODDEF(int)
read_markers(j_decompress_ptr cinfo)954 read_markers (j_decompress_ptr cinfo)
955 {
956 /* Outer loop repeats once for each marker. */
957 for (;;) {
958 /* Collect the marker proper, unless we already did. */
959 /* NB: first_marker() enforces the requirement that SOI appear first. */
960 if (cinfo->unread_marker == 0) {
961 if (! cinfo->marker->saw_SOI) {
962 if (! first_marker(cinfo))
963 return JPEG_SUSPENDED;
964 } else {
965 if (! next_marker(cinfo))
966 return JPEG_SUSPENDED;
967 }
968 }
969 /* At this point cinfo->unread_marker contains the marker code and the
970 * input point is just past the marker proper, but before any parameters.
971 * A suspension will cause us to return with this state still true.
972 */
973 switch (cinfo->unread_marker) {
974 case M_SOI:
975 if (! get_soi(cinfo))
976 return JPEG_SUSPENDED;
977 break;
978
979 case M_SOF0: /* Baseline */
980 case M_SOF1: /* Extended sequential, Huffman */
981 if (! get_sof(cinfo, JPROC_SEQUENTIAL, FALSE, DCTSIZE))
982 return JPEG_SUSPENDED;
983 break;
984
985 case M_SOF2: /* Progressive, Huffman */
986 if (! get_sof(cinfo, JPROC_PROGRESSIVE, FALSE, DCTSIZE))
987 return JPEG_SUSPENDED;
988 break;
989
990 case M_SOF3: /* Lossless, Huffman */
991 if (! get_sof(cinfo, JPROC_LOSSLESS, FALSE, 1))
992 return JPEG_SUSPENDED;
993 break;
994
995 case M_SOF9: /* Extended sequential, arithmetic */
996 if (! get_sof(cinfo, JPROC_SEQUENTIAL, TRUE, DCTSIZE))
997 return JPEG_SUSPENDED;
998 break;
999
1000 case M_SOF10: /* Progressive, arithmetic */
1001 if (! get_sof(cinfo, JPROC_PROGRESSIVE, TRUE, DCTSIZE))
1002 return JPEG_SUSPENDED;
1003 break;
1004
1005 case M_SOF11: /* Lossless, arithmetic */
1006 if (! get_sof(cinfo, JPROC_LOSSLESS, TRUE, 1))
1007 return JPEG_SUSPENDED;
1008 break;
1009
1010 /* Currently unsupported SOFn types */
1011 case M_SOF5: /* Differential sequential, Huffman */
1012 case M_SOF6: /* Differential progressive, Huffman */
1013 case M_SOF7: /* Differential lossless, Huffman */
1014 case M_JPG: /* Reserved for JPEG extensions */
1015 case M_SOF13: /* Differential sequential, arithmetic */
1016 case M_SOF14: /* Differential progressive, arithmetic */
1017 case M_SOF15: /* Differential lossless, arithmetic */
1018 ERREXIT1(cinfo, JERR_SOF_UNSUPPORTED, cinfo->unread_marker);
1019 break;
1020
1021 case M_SOS:
1022 if (! get_sos(cinfo))
1023 return JPEG_SUSPENDED;
1024 cinfo->unread_marker = 0; /* processed the marker */
1025 return JPEG_REACHED_SOS;
1026
1027 case M_EOI:
1028 TRACEMS(cinfo, 1, JTRC_EOI);
1029 cinfo->unread_marker = 0; /* processed the marker */
1030 return JPEG_REACHED_EOI;
1031
1032 case M_DAC:
1033 if (! get_dac(cinfo))
1034 return JPEG_SUSPENDED;
1035 break;
1036
1037 case M_DHT:
1038 if (! get_dht(cinfo))
1039 return JPEG_SUSPENDED;
1040 break;
1041
1042 case M_DQT:
1043 if (! get_dqt(cinfo))
1044 return JPEG_SUSPENDED;
1045 break;
1046
1047 case M_DRI:
1048 if (! get_dri(cinfo))
1049 return JPEG_SUSPENDED;
1050 break;
1051
1052 case M_APP0:
1053 case M_APP1:
1054 case M_APP2:
1055 case M_APP3:
1056 case M_APP4:
1057 case M_APP5:
1058 case M_APP6:
1059 case M_APP7:
1060 case M_APP8:
1061 case M_APP9:
1062 case M_APP10:
1063 case M_APP11:
1064 case M_APP12:
1065 case M_APP13:
1066 case M_APP14:
1067 case M_APP15:
1068 if (! (*((my_marker_ptr) cinfo->marker)->process_APPn[
1069 cinfo->unread_marker - (int) M_APP0]) (cinfo))
1070 return JPEG_SUSPENDED;
1071 break;
1072
1073 case M_COM:
1074 if (! (*((my_marker_ptr) cinfo->marker)->process_COM) (cinfo))
1075 return JPEG_SUSPENDED;
1076 break;
1077
1078 case M_RST0: /* these are all parameterless */
1079 case M_RST1:
1080 case M_RST2:
1081 case M_RST3:
1082 case M_RST4:
1083 case M_RST5:
1084 case M_RST6:
1085 case M_RST7:
1086 case M_TEM:
1087 TRACEMS1(cinfo, 1, JTRC_PARMLESS_MARKER, cinfo->unread_marker);
1088 break;
1089
1090 case M_DNL: /* Ignore DNL ... perhaps the wrong thing */
1091 if (! skip_variable(cinfo))
1092 return JPEG_SUSPENDED;
1093 break;
1094
1095 default: /* must be DHP, EXP, JPGn, or RESn */
1096 /* For now, we treat the reserved markers as fatal errors since they are
1097 * likely to be used to signal incompatible JPEG Part 3 extensions.
1098 * Once the JPEG 3 version-number marker is well defined, this code
1099 * ought to change!
1100 */
1101 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
1102 break;
1103 }
1104 /* Successfully processed marker, so reset state variable */
1105 cinfo->unread_marker = 0;
1106 } /* end loop */
1107 }
1108
1109
1110 /*
1111 * Read a restart marker, which is expected to appear next in the datastream;
1112 * if the marker is not there, take appropriate recovery action.
1113 * Returns FALSE if suspension is required.
1114 *
1115 * This is called by the entropy decoder after it has read an appropriate
1116 * number of MCUs. cinfo->unread_marker may be nonzero if the entropy decoder
1117 * has already read a marker from the data source. Under normal conditions
1118 * cinfo->unread_marker will be reset to 0 before returning; if not reset,
1119 * it holds a marker which the decoder will be unable to read past.
1120 */
1121
1122 METHODDEF(boolean)
read_restart_marker(j_decompress_ptr cinfo)1123 read_restart_marker (j_decompress_ptr cinfo)
1124 {
1125 /* Obtain a marker unless we already did. */
1126 /* Note that next_marker will complain if it skips any data. */
1127 if (cinfo->unread_marker == 0) {
1128 if (! next_marker(cinfo))
1129 return FALSE;
1130 }
1131
1132 if (cinfo->unread_marker ==
1133 ((int) M_RST0 + cinfo->marker->next_restart_num)) {
1134 /* Normal case --- swallow the marker and let entropy decoder continue */
1135 TRACEMS1(cinfo, 3, JTRC_RST, cinfo->marker->next_restart_num);
1136 cinfo->unread_marker = 0;
1137 } else {
1138 /* Uh-oh, the restart markers have been messed up. */
1139 /* Let the data source manager determine how to resync. */
1140 if (! (*cinfo->src->resync_to_restart) (cinfo,
1141 cinfo->marker->next_restart_num))
1142 return FALSE;
1143 }
1144
1145 /* Update next-restart state */
1146 cinfo->marker->next_restart_num = (cinfo->marker->next_restart_num + 1) & 7;
1147
1148 return TRUE;
1149 }
1150
1151
1152 /*
1153 * This is the default resync_to_restart method for data source managers
1154 * to use if they don't have any better approach. Some data source managers
1155 * may be able to back up, or may have additional knowledge about the data
1156 * which permits a more intelligent recovery strategy; such managers would
1157 * presumably supply their own resync method.
1158 *
1159 * read_restart_marker calls resync_to_restart if it finds a marker other than
1160 * the restart marker it was expecting. (This code is *not* used unless
1161 * a nonzero restart interval has been declared.) cinfo->unread_marker is
1162 * the marker code actually found (might be anything, except 0 or FF).
1163 * The desired restart marker number (0..7) is passed as a parameter.
1164 * This routine is supposed to apply whatever error recovery strategy seems
1165 * appropriate in order to position the input stream to the next data segment.
1166 * Note that cinfo->unread_marker is treated as a marker appearing before
1167 * the current data-source input point; usually it should be reset to zero
1168 * before returning.
1169 * Returns FALSE if suspension is required.
1170 *
1171 * This implementation is substantially constrained by wanting to treat the
1172 * input as a data stream; this means we can't back up. Therefore, we have
1173 * only the following actions to work with:
1174 * 1. Simply discard the marker and let the entropy decoder resume at next
1175 * byte of file.
1176 * 2. Read forward until we find another marker, discarding intervening
1177 * data. (In theory we could look ahead within the current bufferload,
1178 * without having to discard data if we don't find the desired marker.
1179 * This idea is not implemented here, in part because it makes behavior
1180 * dependent on buffer size and chance buffer-boundary positions.)
1181 * 3. Leave the marker unread (by failing to zero cinfo->unread_marker).
1182 * This will cause the entropy decoder to process an empty data segment,
1183 * inserting dummy zeroes, and then we will reprocess the marker.
1184 *
1185 * #2 is appropriate if we think the desired marker lies ahead, while #3 is
1186 * appropriate if the found marker is a future restart marker (indicating
1187 * that we have missed the desired restart marker, probably because it got
1188 * corrupted).
1189 * We apply #2 or #3 if the found marker is a restart marker no more than
1190 * two counts behind or ahead of the expected one. We also apply #2 if the
1191 * found marker is not a legal JPEG marker code (it's certainly bogus data).
1192 * If the found marker is a restart marker more than 2 counts away, we do #1
1193 * (too much risk that the marker is erroneous; with luck we will be able to
1194 * resync at some future point).
1195 * For any valid non-restart JPEG marker, we apply #3. This keeps us from
1196 * overrunning the end of a scan. An implementation limited to single-scan
1197 * files might find it better to apply #2 for markers other than EOI, since
1198 * any other marker would have to be bogus data in that case.
1199 */
1200
1201 GLOBAL(boolean)
jpeg_resync_to_restart(j_decompress_ptr cinfo,int desired)1202 jpeg_resync_to_restart (j_decompress_ptr cinfo, int desired)
1203 {
1204 int marker = cinfo->unread_marker;
1205 int action = 1;
1206
1207 /* Always put up a warning. */
1208 WARNMS2(cinfo, JWRN_MUST_RESYNC, marker, desired);
1209
1210 /* Outer loop handles repeated decision after scanning forward. */
1211 for (;;) {
1212 if (marker < (int) M_SOF0)
1213 action = 2; /* invalid marker */
1214 else if (marker < (int) M_RST0 || marker > (int) M_RST7)
1215 action = 3; /* valid non-restart marker */
1216 else {
1217 if (marker == ((int) M_RST0 + ((desired+1) & 7)) ||
1218 marker == ((int) M_RST0 + ((desired+2) & 7)))
1219 action = 3; /* one of the next two expected restarts */
1220 else if (marker == ((int) M_RST0 + ((desired-1) & 7)) ||
1221 marker == ((int) M_RST0 + ((desired-2) & 7)))
1222 action = 2; /* a prior restart, so advance */
1223 else
1224 action = 1; /* desired restart or too far away */
1225 }
1226 TRACEMS2(cinfo, 4, JTRC_RECOVERY_ACTION, marker, action);
1227 switch (action) {
1228 case 1:
1229 /* Discard marker and let entropy decoder resume processing. */
1230 cinfo->unread_marker = 0;
1231 return TRUE;
1232 case 2:
1233 /* Scan to the next marker, and repeat the decision loop. */
1234 if (! next_marker(cinfo))
1235 return FALSE;
1236 marker = cinfo->unread_marker;
1237 break;
1238 case 3:
1239 /* Return without advancing past this marker. */
1240 /* Entropy decoder will be forced to process an empty segment. */
1241 return TRUE;
1242 }
1243 } /* end loop */
1244 }
1245
1246
1247 /*
1248 * Reset marker processing state to begin a fresh datastream.
1249 */
1250
1251 METHODDEF(void)
reset_marker_reader(j_decompress_ptr cinfo)1252 reset_marker_reader (j_decompress_ptr cinfo)
1253 {
1254 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1255
1256 cinfo->comp_info = NULL; /* until allocated by get_sof */
1257 cinfo->input_scan_number = 0; /* no SOS seen yet */
1258 cinfo->unread_marker = 0; /* no pending marker */
1259 marker->pub.saw_SOI = FALSE; /* set internal state too */
1260 marker->pub.saw_SOF = FALSE;
1261 marker->pub.discarded_bytes = 0;
1262 marker->cur_marker = NULL;
1263 }
1264
1265
1266 /*
1267 * Initialize the marker reader module.
1268 * This is called only once, when the decompression object is created.
1269 */
1270
1271 GLOBAL(void)
jinit_marker_reader(j_decompress_ptr cinfo)1272 jinit_marker_reader (j_decompress_ptr cinfo)
1273 {
1274 my_marker_ptr marker;
1275 int i;
1276
1277 /* Create subobject in permanent pool */
1278 marker = (my_marker_ptr)
1279 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
1280 SIZEOF(my_marker_reader));
1281 cinfo->marker = (struct jpeg_marker_reader *) marker;
1282 /* Initialize public method pointers */
1283 marker->pub.reset_marker_reader = reset_marker_reader;
1284 marker->pub.read_markers = read_markers;
1285 marker->pub.read_restart_marker = read_restart_marker;
1286 /* Initialize COM/APPn processing.
1287 * By default, we examine and then discard APP0 and APP14,
1288 * but simply discard COM and all other APPn.
1289 */
1290 marker->process_COM = skip_variable;
1291 marker->length_limit_COM = 0;
1292 for (i = 0; i < 16; i++) {
1293 marker->process_APPn[i] = skip_variable;
1294 marker->length_limit_APPn[i] = 0;
1295 }
1296 marker->process_APPn[0] = get_interesting_appn;
1297 marker->process_APPn[14] = get_interesting_appn;
1298 /* Reset marker processing state */
1299 reset_marker_reader(cinfo);
1300 }
1301
1302
1303 /*
1304 * Control saving of COM and APPn markers into marker_list.
1305 */
1306
1307 #ifdef SAVE_MARKERS_SUPPORTED
1308
1309 GLOBAL(void)
jpeg_save_markers(j_decompress_ptr cinfo,int marker_code,unsigned int length_limit)1310 jpeg_save_markers (j_decompress_ptr cinfo, int marker_code,
1311 unsigned int length_limit)
1312 {
1313 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1314 long maxlength;
1315 jpeg_marker_parser_method processor;
1316
1317 /* Length limit mustn't be larger than what we can allocate
1318 * (should only be a concern in a 16-bit environment).
1319 */
1320 maxlength = cinfo->mem->max_alloc_chunk - (long)SIZEOF(struct jpeg_marker_struct);
1321 if (((long) length_limit) > maxlength)
1322 length_limit = (unsigned int) maxlength;
1323
1324 /* Choose processor routine to use.
1325 * APP0/APP14 have special requirements.
1326 */
1327 if (length_limit) {
1328 processor = save_marker;
1329 /* If saving APP0/APP14, save at least enough for our internal use. */
1330 if (marker_code == (int) M_APP0 && length_limit < APP0_DATA_LEN)
1331 length_limit = APP0_DATA_LEN;
1332 else if (marker_code == (int) M_APP14 && length_limit < APP14_DATA_LEN)
1333 length_limit = APP14_DATA_LEN;
1334 } else {
1335 processor = skip_variable;
1336 /* If discarding APP0/APP14, use our regular on-the-fly processor. */
1337 if (marker_code == (int) M_APP0 || marker_code == (int) M_APP14)
1338 processor = get_interesting_appn;
1339 }
1340
1341 if (marker_code == (int) M_COM) {
1342 marker->process_COM = processor;
1343 marker->length_limit_COM = length_limit;
1344 } else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15) {
1345 marker->process_APPn[marker_code - (int) M_APP0] = processor;
1346 marker->length_limit_APPn[marker_code - (int) M_APP0] = length_limit;
1347 } else
1348 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
1349 }
1350
1351 #endif /* SAVE_MARKERS_SUPPORTED */
1352
1353
1354 /*
1355 * Install a special processing method for COM or APPn markers.
1356 */
1357
1358 GLOBAL(void)
jpeg_set_marker_processor(j_decompress_ptr cinfo,int marker_code,jpeg_marker_parser_method routine)1359 jpeg_set_marker_processor (j_decompress_ptr cinfo, int marker_code,
1360 jpeg_marker_parser_method routine)
1361 {
1362 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1363
1364 if (marker_code == (int) M_COM)
1365 marker->process_COM = routine;
1366 else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15)
1367 marker->process_APPn[marker_code - (int) M_APP0] = routine;
1368 else
1369 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
1370 }
1371