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 INPUT_VARS(cinfo);
244
245 cinfo->progressive_mode = is_prog;
246 cinfo->arith_code = is_arith;
247
248 INPUT_2BYTES(cinfo, length, return FALSE);
249
250 INPUT_BYTE(cinfo, cinfo->data_precision, return FALSE);
251 INPUT_2BYTES(cinfo, cinfo->image_height, return FALSE);
252 INPUT_2BYTES(cinfo, cinfo->image_width, return FALSE);
253 INPUT_BYTE(cinfo, cinfo->num_components, return FALSE);
254
255 length -= 8;
256
257 TRACEMS4(cinfo, 1, JTRC_SOF, cinfo->unread_marker,
258 (int) cinfo->image_width, (int) cinfo->image_height,
259 cinfo->num_components);
260
261 if (cinfo->marker->saw_SOF)
262 ERREXIT(cinfo, JERR_SOF_DUPLICATE);
263
264 /* We don't support files in which the image height is initially specified */
265 /* as 0 and is later redefined by DNL. As long as we have to check that, */
266 /* might as well have a general sanity check. */
267 if (cinfo->image_height <= 0 || cinfo->image_width <= 0
268 || cinfo->num_components <= 0)
269 ERREXIT(cinfo, JERR_EMPTY_IMAGE);
270
271 if (length != (cinfo->num_components * 3))
272 ERREXIT(cinfo, JERR_BAD_LENGTH);
273
274 if (cinfo->comp_info == NULL) /* do only once, even if suspend */
275 cinfo->comp_info = (jpeg_component_info *) (*cinfo->mem->alloc_small)
276 ((j_common_ptr) cinfo, JPOOL_IMAGE,
277 cinfo->num_components * SIZEOF(jpeg_component_info));
278
279 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
280 ci++, compptr++) {
281 compptr->component_index = ci;
282 INPUT_BYTE(cinfo, compptr->component_id, return FALSE);
283 INPUT_BYTE(cinfo, c, return FALSE);
284 compptr->h_samp_factor = (c >> 4) & 15;
285 compptr->v_samp_factor = (c ) & 15;
286 INPUT_BYTE(cinfo, compptr->quant_tbl_no, return FALSE);
287
288 TRACEMS4(cinfo, 1, JTRC_SOF_COMPONENT,
289 compptr->component_id, compptr->h_samp_factor,
290 compptr->v_samp_factor, compptr->quant_tbl_no);
291 }
292
293 cinfo->marker->saw_SOF = TRUE;
294
295 INPUT_SYNC(cinfo);
296 return TRUE;
297 }
298
299
300 LOCAL(boolean)
get_sos(j_decompress_ptr cinfo)301 get_sos (j_decompress_ptr cinfo)
302 /* Process a SOS marker */
303 {
304 INT32 length;
305 int i, ci, n, c, cc, pi;
306 jpeg_component_info * compptr;
307 INPUT_VARS(cinfo);
308
309 if (! cinfo->marker->saw_SOF)
310 ERREXIT(cinfo, JERR_SOS_NO_SOF);
311
312 INPUT_2BYTES(cinfo, length, return FALSE);
313
314 INPUT_BYTE(cinfo, n, return FALSE); /* Number of components */
315
316 TRACEMS1(cinfo, 1, JTRC_SOS, n);
317
318 if (length != (n * 2 + 6) || n < 1 || n > MAX_COMPS_IN_SCAN)
319 ERREXIT(cinfo, JERR_BAD_LENGTH);
320
321 cinfo->comps_in_scan = n;
322
323 /* Collect the component-spec parameters */
324
325 for (i = 0; i < n; i++) {
326 INPUT_BYTE(cinfo, cc, return FALSE);
327 INPUT_BYTE(cinfo, c, return FALSE);
328
329 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
330 ci++, compptr++) {
331 if (cc == compptr->component_id)
332 goto id_found;
333 }
334
335 ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc);
336
337 id_found:
338
339 cinfo->cur_comp_info[i] = compptr;
340 compptr->dc_tbl_no = (c >> 4) & 15;
341 compptr->ac_tbl_no = (c ) & 15;
342
343 TRACEMS3(cinfo, 1, JTRC_SOS_COMPONENT, cc,
344 compptr->dc_tbl_no, compptr->ac_tbl_no);
345
346 /* This CSi (cc) should differ from the previous CSi */
347 for (pi = 0; pi < i; pi++) {
348 if (cinfo->cur_comp_info[pi] == compptr)
349 ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc);
350 }
351 }
352
353 /* Collect the additional scan parameters Ss, Se, Ah/Al. */
354 INPUT_BYTE(cinfo, c, return FALSE);
355 cinfo->Ss = c;
356 INPUT_BYTE(cinfo, c, return FALSE);
357 cinfo->Se = c;
358 INPUT_BYTE(cinfo, c, return FALSE);
359 cinfo->Ah = (c >> 4) & 15;
360 cinfo->Al = (c ) & 15;
361
362 TRACEMS4(cinfo, 1, JTRC_SOS_PARAMS, cinfo->Ss, cinfo->Se,
363 cinfo->Ah, cinfo->Al);
364
365 /* Prepare to scan data & restart markers */
366 cinfo->marker->next_restart_num = 0;
367
368 /* Count another SOS marker */
369 cinfo->input_scan_number++;
370
371 INPUT_SYNC(cinfo);
372 return TRUE;
373 }
374
375
376 #ifdef D_ARITH_CODING_SUPPORTED
377
378 LOCAL(boolean)
get_dac(j_decompress_ptr cinfo)379 get_dac (j_decompress_ptr cinfo)
380 /* Process a DAC marker */
381 {
382 INT32 length;
383 int index, val;
384 INPUT_VARS(cinfo);
385
386 INPUT_2BYTES(cinfo, length, return FALSE);
387 length -= 2;
388
389 while (length > 0) {
390 INPUT_BYTE(cinfo, index, return FALSE);
391 INPUT_BYTE(cinfo, val, return FALSE);
392
393 length -= 2;
394
395 TRACEMS2(cinfo, 1, JTRC_DAC, index, val);
396
397 if (index < 0 || index >= (2*NUM_ARITH_TBLS))
398 ERREXIT1(cinfo, JERR_DAC_INDEX, index);
399
400 if (index >= NUM_ARITH_TBLS) { /* define AC table */
401 cinfo->arith_ac_K[index-NUM_ARITH_TBLS] = (UINT8) val;
402 } else { /* define DC table */
403 cinfo->arith_dc_L[index] = (UINT8) (val & 0x0F);
404 cinfo->arith_dc_U[index] = (UINT8) (val >> 4);
405 if (cinfo->arith_dc_L[index] > cinfo->arith_dc_U[index])
406 ERREXIT1(cinfo, JERR_DAC_VALUE, val);
407 }
408 }
409
410 if (length != 0)
411 ERREXIT(cinfo, JERR_BAD_LENGTH);
412
413 INPUT_SYNC(cinfo);
414 return TRUE;
415 }
416
417 #else /* ! D_ARITH_CODING_SUPPORTED */
418
419 #define get_dac(cinfo) skip_variable(cinfo)
420
421 #endif /* D_ARITH_CODING_SUPPORTED */
422
423
424 LOCAL(boolean)
get_dht(j_decompress_ptr cinfo)425 get_dht (j_decompress_ptr cinfo)
426 /* Process a DHT marker */
427 {
428 INT32 length;
429 UINT8 bits[17];
430 UINT8 huffval[256];
431 int i, index, count;
432 JHUFF_TBL **htblptr;
433 INPUT_VARS(cinfo);
434
435 INPUT_2BYTES(cinfo, length, return FALSE);
436 length -= 2;
437
438 while (length > 16) {
439 INPUT_BYTE(cinfo, index, return FALSE);
440
441 TRACEMS1(cinfo, 1, JTRC_DHT, index);
442
443 bits[0] = 0;
444 count = 0;
445 for (i = 1; i <= 16; i++) {
446 INPUT_BYTE(cinfo, bits[i], return FALSE);
447 count += bits[i];
448 }
449
450 length -= 1 + 16;
451
452 TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
453 bits[1], bits[2], bits[3], bits[4],
454 bits[5], bits[6], bits[7], bits[8]);
455 TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
456 bits[9], bits[10], bits[11], bits[12],
457 bits[13], bits[14], bits[15], bits[16]);
458
459 /* Here we just do minimal validation of the counts to avoid walking
460 * off the end of our table space. jdhuff.c will check more carefully.
461 */
462 if (count > 256 || ((INT32) count) > length)
463 ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
464
465 for (i = 0; i < count; i++)
466 INPUT_BYTE(cinfo, huffval[i], return FALSE);
467
468 MEMZERO(&huffval[count], (256 - count) * SIZEOF(UINT8));
469
470 length -= count;
471
472 if (index & 0x10) { /* AC table definition */
473 index -= 0x10;
474 htblptr = &cinfo->ac_huff_tbl_ptrs[index];
475 } else { /* DC table definition */
476 htblptr = &cinfo->dc_huff_tbl_ptrs[index];
477 }
478
479 if (index < 0 || index >= NUM_HUFF_TBLS)
480 ERREXIT1(cinfo, JERR_DHT_INDEX, index);
481
482 if (*htblptr == NULL)
483 *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
484
485 MEMCOPY((*htblptr)->bits, bits, SIZEOF((*htblptr)->bits));
486 MEMCOPY((*htblptr)->huffval, huffval, SIZEOF((*htblptr)->huffval));
487 }
488
489 if (length != 0)
490 ERREXIT(cinfo, JERR_BAD_LENGTH);
491
492 INPUT_SYNC(cinfo);
493 return TRUE;
494 }
495
496
497 LOCAL(boolean)
get_dqt(j_decompress_ptr cinfo)498 get_dqt (j_decompress_ptr cinfo)
499 /* Process a DQT marker */
500 {
501 INT32 length;
502 int n, i, prec;
503 unsigned int tmp;
504 JQUANT_TBL *quant_ptr;
505 INPUT_VARS(cinfo);
506
507 INPUT_2BYTES(cinfo, length, return FALSE);
508 length -= 2;
509
510 while (length > 0) {
511 INPUT_BYTE(cinfo, n, return FALSE);
512 prec = n >> 4;
513 n &= 0x0F;
514
515 TRACEMS2(cinfo, 1, JTRC_DQT, n, prec);
516
517 if (n >= NUM_QUANT_TBLS)
518 ERREXIT1(cinfo, JERR_DQT_INDEX, n);
519
520 if (cinfo->quant_tbl_ptrs[n] == NULL)
521 cinfo->quant_tbl_ptrs[n] = jpeg_alloc_quant_table((j_common_ptr) cinfo);
522 quant_ptr = cinfo->quant_tbl_ptrs[n];
523
524 for (i = 0; i < DCTSIZE2; i++) {
525 if (prec)
526 INPUT_2BYTES(cinfo, tmp, return FALSE);
527 else
528 INPUT_BYTE(cinfo, tmp, return FALSE);
529 /* We convert the zigzag-order table to natural array order. */
530 quant_ptr->quantval[jpeg_natural_order[i]] = (UINT16) tmp;
531 }
532
533 if (cinfo->err->trace_level >= 2) {
534 for (i = 0; i < DCTSIZE2; i += 8) {
535 TRACEMS8(cinfo, 2, JTRC_QUANTVALS,
536 quant_ptr->quantval[i], quant_ptr->quantval[i+1],
537 quant_ptr->quantval[i+2], quant_ptr->quantval[i+3],
538 quant_ptr->quantval[i+4], quant_ptr->quantval[i+5],
539 quant_ptr->quantval[i+6], quant_ptr->quantval[i+7]);
540 }
541 }
542
543 length -= DCTSIZE2+1;
544 if (prec) length -= DCTSIZE2;
545 }
546
547 if (length != 0)
548 ERREXIT(cinfo, JERR_BAD_LENGTH);
549
550 INPUT_SYNC(cinfo);
551 return TRUE;
552 }
553
554
555 LOCAL(boolean)
get_dri(j_decompress_ptr cinfo)556 get_dri (j_decompress_ptr cinfo)
557 /* Process a DRI marker */
558 {
559 INT32 length;
560 unsigned int tmp;
561 INPUT_VARS(cinfo);
562
563 INPUT_2BYTES(cinfo, length, return FALSE);
564
565 if (length != 4)
566 ERREXIT(cinfo, JERR_BAD_LENGTH);
567
568 INPUT_2BYTES(cinfo, tmp, return FALSE);
569
570 TRACEMS1(cinfo, 1, JTRC_DRI, tmp);
571
572 cinfo->restart_interval = tmp;
573
574 INPUT_SYNC(cinfo);
575 return TRUE;
576 }
577
578
579 /*
580 * Routines for processing APPn and COM markers.
581 * These are either saved in memory or discarded, per application request.
582 * APP0 and APP14 are specially checked to see if they are
583 * JFIF and Adobe markers, respectively.
584 */
585
586 #define APP0_DATA_LEN 14 /* Length of interesting data in APP0 */
587 #define APP14_DATA_LEN 12 /* Length of interesting data in APP14 */
588 #define APPN_DATA_LEN 14 /* Must be the largest of the above!! */
589
590
591 LOCAL(void)
examine_app0(j_decompress_ptr cinfo,JOCTET FAR * data,unsigned int datalen,INT32 remaining)592 examine_app0 (j_decompress_ptr cinfo, JOCTET FAR * data,
593 unsigned int datalen, INT32 remaining)
594 /* Examine first few bytes from an APP0.
595 * Take appropriate action if it is a JFIF marker.
596 * datalen is # of bytes at data[], remaining is length of rest of marker data.
597 */
598 {
599 INT32 totallen = (INT32) datalen + remaining;
600
601 if (datalen >= APP0_DATA_LEN &&
602 GETJOCTET(data[0]) == 0x4A &&
603 GETJOCTET(data[1]) == 0x46 &&
604 GETJOCTET(data[2]) == 0x49 &&
605 GETJOCTET(data[3]) == 0x46 &&
606 GETJOCTET(data[4]) == 0) {
607 /* Found JFIF APP0 marker: save info */
608 cinfo->saw_JFIF_marker = TRUE;
609 cinfo->JFIF_major_version = GETJOCTET(data[5]);
610 cinfo->JFIF_minor_version = GETJOCTET(data[6]);
611 cinfo->density_unit = GETJOCTET(data[7]);
612 cinfo->X_density = (GETJOCTET(data[8]) << 8) + GETJOCTET(data[9]);
613 cinfo->Y_density = (GETJOCTET(data[10]) << 8) + GETJOCTET(data[11]);
614 /* Check version.
615 * Major version must be 1, anything else signals an incompatible change.
616 * (We used to treat this as an error, but now it's a nonfatal warning,
617 * because some bozo at Hijaak couldn't read the spec.)
618 * Minor version should be 0..2, but process anyway if newer.
619 */
620 if (cinfo->JFIF_major_version != 1)
621 WARNMS2(cinfo, JWRN_JFIF_MAJOR,
622 cinfo->JFIF_major_version, cinfo->JFIF_minor_version);
623 /* Generate trace messages */
624 TRACEMS5(cinfo, 1, JTRC_JFIF,
625 cinfo->JFIF_major_version, cinfo->JFIF_minor_version,
626 cinfo->X_density, cinfo->Y_density, cinfo->density_unit);
627 /* Validate thumbnail dimensions and issue appropriate messages */
628 if (GETJOCTET(data[12]) | GETJOCTET(data[13]))
629 TRACEMS2(cinfo, 1, JTRC_JFIF_THUMBNAIL,
630 GETJOCTET(data[12]), GETJOCTET(data[13]));
631 totallen -= APP0_DATA_LEN;
632 if (totallen !=
633 ((INT32)GETJOCTET(data[12]) * (INT32)GETJOCTET(data[13]) * (INT32) 3))
634 TRACEMS1(cinfo, 1, JTRC_JFIF_BADTHUMBNAILSIZE, (int) totallen);
635 } else if (datalen >= 6 &&
636 GETJOCTET(data[0]) == 0x4A &&
637 GETJOCTET(data[1]) == 0x46 &&
638 GETJOCTET(data[2]) == 0x58 &&
639 GETJOCTET(data[3]) == 0x58 &&
640 GETJOCTET(data[4]) == 0) {
641 /* Found JFIF "JFXX" extension APP0 marker */
642 /* The library doesn't actually do anything with these,
643 * but we try to produce a helpful trace message.
644 */
645 switch (GETJOCTET(data[5])) {
646 case 0x10:
647 TRACEMS1(cinfo, 1, JTRC_THUMB_JPEG, (int) totallen);
648 break;
649 case 0x11:
650 TRACEMS1(cinfo, 1, JTRC_THUMB_PALETTE, (int) totallen);
651 break;
652 case 0x13:
653 TRACEMS1(cinfo, 1, JTRC_THUMB_RGB, (int) totallen);
654 break;
655 default:
656 TRACEMS2(cinfo, 1, JTRC_JFIF_EXTENSION,
657 GETJOCTET(data[5]), (int) totallen);
658 break;
659 }
660 } else {
661 /* Start of APP0 does not match "JFIF" or "JFXX", or too short */
662 TRACEMS1(cinfo, 1, JTRC_APP0, (int) totallen);
663 }
664 }
665
666
667 LOCAL(void)
examine_app14(j_decompress_ptr cinfo,JOCTET FAR * data,unsigned int datalen,INT32 remaining)668 examine_app14 (j_decompress_ptr cinfo, JOCTET FAR * data,
669 unsigned int datalen, INT32 remaining)
670 /* Examine first few bytes from an APP14.
671 * Take appropriate action if it is an Adobe marker.
672 * datalen is # of bytes at data[], remaining is length of rest of marker data.
673 */
674 {
675 unsigned int version, flags0, flags1, transform;
676
677 if (datalen >= APP14_DATA_LEN &&
678 GETJOCTET(data[0]) == 0x41 &&
679 GETJOCTET(data[1]) == 0x64 &&
680 GETJOCTET(data[2]) == 0x6F &&
681 GETJOCTET(data[3]) == 0x62 &&
682 GETJOCTET(data[4]) == 0x65) {
683 /* Found Adobe APP14 marker */
684 version = (GETJOCTET(data[5]) << 8) + GETJOCTET(data[6]);
685 flags0 = (GETJOCTET(data[7]) << 8) + GETJOCTET(data[8]);
686 flags1 = (GETJOCTET(data[9]) << 8) + GETJOCTET(data[10]);
687 transform = GETJOCTET(data[11]);
688 TRACEMS4(cinfo, 1, JTRC_ADOBE, version, flags0, flags1, transform);
689 cinfo->saw_Adobe_marker = TRUE;
690 cinfo->Adobe_transform = (UINT8) transform;
691 } else {
692 /* Start of APP14 does not match "Adobe", or too short */
693 TRACEMS1(cinfo, 1, JTRC_APP14, (int) (datalen + remaining));
694 }
695 }
696
697
698 METHODDEF(boolean)
get_interesting_appn(j_decompress_ptr cinfo)699 get_interesting_appn (j_decompress_ptr cinfo)
700 /* Process an APP0 or APP14 marker without saving it */
701 {
702 INT32 length;
703 JOCTET b[APPN_DATA_LEN];
704 unsigned int i, numtoread;
705 INPUT_VARS(cinfo);
706
707 INPUT_2BYTES(cinfo, length, return FALSE);
708 length -= 2;
709
710 /* get the interesting part of the marker data */
711 if (length >= APPN_DATA_LEN)
712 numtoread = APPN_DATA_LEN;
713 else if (length > 0)
714 numtoread = (unsigned int) length;
715 else
716 numtoread = 0;
717 for (i = 0; i < numtoread; i++)
718 INPUT_BYTE(cinfo, b[i], return FALSE);
719 length -= numtoread;
720
721 /* process it */
722 switch (cinfo->unread_marker) {
723 case M_APP0:
724 examine_app0(cinfo, (JOCTET FAR *) b, numtoread, length);
725 break;
726 case M_APP14:
727 examine_app14(cinfo, (JOCTET FAR *) b, numtoread, length);
728 break;
729 default:
730 /* can't get here unless jpeg_save_markers chooses wrong processor */
731 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
732 break;
733 }
734
735 /* skip any remaining data -- could be lots */
736 INPUT_SYNC(cinfo);
737 if (length > 0)
738 (*cinfo->src->skip_input_data) (cinfo, (long) length);
739
740 return TRUE;
741 }
742
743
744 #ifdef SAVE_MARKERS_SUPPORTED
745
746 METHODDEF(boolean)
save_marker(j_decompress_ptr cinfo)747 save_marker (j_decompress_ptr cinfo)
748 /* Save an APPn or COM marker into the marker list */
749 {
750 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
751 jpeg_saved_marker_ptr cur_marker = marker->cur_marker;
752 unsigned int bytes_read, data_length;
753 JOCTET FAR * data;
754 INT32 length = 0;
755 INPUT_VARS(cinfo);
756
757 if (cur_marker == NULL) {
758 /* begin reading a marker */
759 INPUT_2BYTES(cinfo, length, return FALSE);
760 length -= 2;
761 if (length >= 0) { /* watch out for bogus length word */
762 /* figure out how much we want to save */
763 unsigned int limit;
764 if (cinfo->unread_marker == (int) M_COM)
765 limit = marker->length_limit_COM;
766 else
767 limit = marker->length_limit_APPn[cinfo->unread_marker - (int) M_APP0];
768 if ((unsigned int) length < limit)
769 limit = (unsigned int) length;
770 /* allocate and initialize the marker item */
771 cur_marker = (jpeg_saved_marker_ptr)
772 (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
773 SIZEOF(struct jpeg_marker_struct) + limit);
774 cur_marker->next = NULL;
775 cur_marker->marker = (UINT8) cinfo->unread_marker;
776 cur_marker->original_length = (unsigned int) length;
777 cur_marker->data_length = limit;
778 /* data area is just beyond the jpeg_marker_struct */
779 data = cur_marker->data = (JOCTET FAR *) (cur_marker + 1);
780 marker->cur_marker = cur_marker;
781 marker->bytes_read = 0;
782 bytes_read = 0;
783 data_length = limit;
784 } else {
785 /* deal with bogus length word */
786 bytes_read = data_length = 0;
787 data = NULL;
788 }
789 } else {
790 /* resume reading a marker */
791 bytes_read = marker->bytes_read;
792 data_length = cur_marker->data_length;
793 data = cur_marker->data + bytes_read;
794 }
795
796 while (bytes_read < data_length) {
797 INPUT_SYNC(cinfo); /* move the restart point to here */
798 marker->bytes_read = bytes_read;
799 /* If there's not at least one byte in buffer, suspend */
800 MAKE_BYTE_AVAIL(cinfo, return FALSE);
801 /* Copy bytes with reasonable rapidity */
802 while (bytes_read < data_length && bytes_in_buffer > 0) {
803 *data++ = *next_input_byte++;
804 bytes_in_buffer--;
805 bytes_read++;
806 }
807 }
808
809 /* Done reading what we want to read */
810 if (cur_marker != NULL) { /* will be NULL if bogus length word */
811 /* Add new marker to end of list */
812 if (cinfo->marker_list == NULL) {
813 cinfo->marker_list = cur_marker;
814 } else {
815 jpeg_saved_marker_ptr prev = cinfo->marker_list;
816 while (prev->next != NULL)
817 prev = prev->next;
818 prev->next = cur_marker;
819 }
820 /* Reset pointer & calc remaining data length */
821 data = cur_marker->data;
822 length = cur_marker->original_length - data_length;
823 }
824 /* Reset to initial state for next marker */
825 marker->cur_marker = NULL;
826
827 /* Process the marker if interesting; else just make a generic trace msg */
828 switch (cinfo->unread_marker) {
829 case M_APP0:
830 examine_app0(cinfo, data, data_length, length);
831 break;
832 case M_APP14:
833 examine_app14(cinfo, data, data_length, length);
834 break;
835 default:
836 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker,
837 (int) (data_length + length));
838 break;
839 }
840
841 /* skip any remaining data -- could be lots */
842 INPUT_SYNC(cinfo); /* do before skip_input_data */
843 if (length > 0)
844 (*cinfo->src->skip_input_data) (cinfo, (long) length);
845
846 return TRUE;
847 }
848
849 #endif /* SAVE_MARKERS_SUPPORTED */
850
851
852 METHODDEF(boolean)
skip_variable(j_decompress_ptr cinfo)853 skip_variable (j_decompress_ptr cinfo)
854 /* Skip over an unknown or uninteresting variable-length marker */
855 {
856 INT32 length;
857 INPUT_VARS(cinfo);
858
859 INPUT_2BYTES(cinfo, length, return FALSE);
860 length -= 2;
861
862 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, (int) length);
863
864 INPUT_SYNC(cinfo); /* do before skip_input_data */
865 if (length > 0)
866 (*cinfo->src->skip_input_data) (cinfo, (long) length);
867
868 return TRUE;
869 }
870
871
872 /*
873 * Find the next JPEG marker, save it in cinfo->unread_marker.
874 * Returns FALSE if had to suspend before reaching a marker;
875 * in that case cinfo->unread_marker is unchanged.
876 *
877 * Note that the result might not be a valid marker code,
878 * but it will never be 0 or FF.
879 */
880
881 LOCAL(boolean)
next_marker(j_decompress_ptr cinfo)882 next_marker (j_decompress_ptr cinfo)
883 {
884 int c;
885 INPUT_VARS(cinfo);
886
887 for (;;) {
888 INPUT_BYTE(cinfo, c, return FALSE);
889 /* Skip any non-FF bytes.
890 * This may look a bit inefficient, but it will not occur in a valid file.
891 * We sync after each discarded byte so that a suspending data source
892 * can discard the byte from its buffer.
893 */
894 while (c != 0xFF) {
895 cinfo->marker->discarded_bytes++;
896 INPUT_SYNC(cinfo);
897 INPUT_BYTE(cinfo, c, return FALSE);
898 }
899 /* This loop swallows any duplicate FF bytes. Extra FFs are legal as
900 * pad bytes, so don't count them in discarded_bytes. We assume there
901 * will not be so many consecutive FF bytes as to overflow a suspending
902 * data source's input buffer.
903 */
904 do {
905 INPUT_BYTE(cinfo, c, return FALSE);
906 } while (c == 0xFF);
907 if (c != 0)
908 break; /* found a valid marker, exit loop */
909 /* Reach here if we found a stuffed-zero data sequence (FF/00).
910 * Discard it and loop back to try again.
911 */
912 cinfo->marker->discarded_bytes += 2;
913 INPUT_SYNC(cinfo);
914 }
915
916 if (cinfo->marker->discarded_bytes != 0) {
917 WARNMS2(cinfo, JWRN_EXTRANEOUS_DATA, cinfo->marker->discarded_bytes, c);
918 cinfo->marker->discarded_bytes = 0;
919 }
920
921 cinfo->unread_marker = c;
922
923 INPUT_SYNC(cinfo);
924 return TRUE;
925 }
926
927
928 LOCAL(boolean)
first_marker(j_decompress_ptr cinfo)929 first_marker (j_decompress_ptr cinfo)
930 /* Like next_marker, but used to obtain the initial SOI marker. */
931 /* For this marker, we do not allow preceding garbage or fill; otherwise,
932 * we might well scan an entire input file before realizing it ain't JPEG.
933 * If an application wants to process non-JFIF files, it must seek to the
934 * SOI before calling the JPEG library.
935 */
936 {
937 int c, c2;
938 INPUT_VARS(cinfo);
939
940 INPUT_BYTE(cinfo, c, return FALSE);
941 INPUT_BYTE(cinfo, c2, return FALSE);
942 if (c != 0xFF || c2 != (int) M_SOI)
943 ERREXIT2(cinfo, JERR_NO_SOI, c, c2);
944
945 cinfo->unread_marker = c2;
946
947 INPUT_SYNC(cinfo);
948 return TRUE;
949 }
950
951
952 /*
953 * Read markers until SOS or EOI.
954 *
955 * Returns same codes as are defined for jpeg_consume_input:
956 * JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
957 */
958
959 METHODDEF(int)
read_markers(j_decompress_ptr cinfo)960 read_markers (j_decompress_ptr cinfo)
961 {
962 /* Outer loop repeats once for each marker. */
963 for (;;) {
964 /* Collect the marker proper, unless we already did. */
965 /* NB: first_marker() enforces the requirement that SOI appear first. */
966 if (cinfo->unread_marker == 0) {
967 if (! cinfo->marker->saw_SOI) {
968 if (! first_marker(cinfo))
969 return JPEG_SUSPENDED;
970 } else {
971 if (! next_marker(cinfo))
972 return JPEG_SUSPENDED;
973 }
974 }
975
976 /*
977 * Save the position of the fist marker after SOF.
978 */
979 if (cinfo->marker->current_sos_marker_position == -1)
980 cinfo->marker->current_sos_marker_position =
981 jget_input_stream_position(cinfo) - 2;
982
983 /* At this point cinfo->unread_marker contains the marker code and the
984 * input point is just past the marker proper, but before any parameters.
985 * A suspension will cause us to return with this state still true.
986 */
987 switch (cinfo->unread_marker) {
988 case M_SOI:
989 if (! get_soi(cinfo))
990 return JPEG_SUSPENDED;
991 break;
992
993 case M_SOF0: /* Baseline */
994 case M_SOF1: /* Extended sequential, Huffman */
995 if (! get_sof(cinfo, FALSE, FALSE))
996 return JPEG_SUSPENDED;
997 break;
998
999 case M_SOF2: /* Progressive, Huffman */
1000 cinfo->marker->current_sos_marker_position = -1;
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 * Get the position for all SOS markers in the image.
1255 */
1256
1257 METHODDEF(void)
get_sos_marker_position(j_decompress_ptr cinfo,huffman_index * index)1258 get_sos_marker_position(j_decompress_ptr cinfo, huffman_index *index)
1259 {
1260 unsigned char *head;
1261 int count = 0;
1262 int retcode = JPEG_REACHED_SOS;
1263
1264 while (cinfo->src->bytes_in_buffer > 0) {
1265 if (retcode == JPEG_REACHED_SOS) {
1266 jpeg_configure_huffman_index_scan(cinfo, index, count++,
1267 cinfo->marker->current_sos_marker_position);
1268 // Skips scan content to the next non-RST JPEG marker.
1269 while(next_marker(cinfo) &&
1270 cinfo->unread_marker >= M_RST0 && cinfo->unread_marker <= M_RST7)
1271 ;
1272 cinfo->marker->current_sos_marker_position =
1273 jget_input_stream_position(cinfo) - 2;
1274 retcode = read_markers(cinfo);
1275 } else {
1276 break;
1277 }
1278 }
1279 }
1280
1281 /*
1282 * Reset marker processing state to begin a fresh datastream.
1283 */
1284
1285 METHODDEF(void)
reset_marker_reader(j_decompress_ptr cinfo)1286 reset_marker_reader (j_decompress_ptr cinfo)
1287 {
1288 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1289
1290 cinfo->comp_info = NULL; /* until allocated by get_sof */
1291 cinfo->input_scan_number = 0; /* no SOS seen yet */
1292 cinfo->unread_marker = 0; /* no pending marker */
1293 marker->pub.saw_SOI = FALSE; /* set internal state too */
1294 marker->pub.saw_SOF = FALSE;
1295 marker->pub.discarded_bytes = 0;
1296 marker->cur_marker = NULL;
1297 }
1298
1299
1300 /*
1301 * Initialize the marker reader module.
1302 * This is called only once, when the decompression object is created.
1303 */
1304
1305 GLOBAL(void)
jinit_marker_reader(j_decompress_ptr cinfo)1306 jinit_marker_reader (j_decompress_ptr cinfo)
1307 {
1308 my_marker_ptr marker;
1309 int i;
1310
1311 /* Create subobject in permanent pool */
1312 marker = (my_marker_ptr)
1313 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
1314 SIZEOF(my_marker_reader));
1315 cinfo->marker = (struct jpeg_marker_reader *) marker;
1316 /* Initialize public method pointers */
1317 marker->pub.reset_marker_reader = reset_marker_reader;
1318 marker->pub.read_markers = read_markers;
1319 marker->pub.read_restart_marker = read_restart_marker;
1320 marker->pub.get_sos_marker_position = get_sos_marker_position;
1321
1322 // Initialize the SOS marker position to avoid underdefined behavior due to
1323 // using a undefined field.
1324 marker->pub.current_sos_marker_position = 0;
1325
1326 /* Initialize COM/APPn processing.
1327 * By default, we examine and then discard APP0 and APP14,
1328 * but simply discard COM and all other APPn.
1329 */
1330 marker->process_COM = skip_variable;
1331 marker->length_limit_COM = 0;
1332 for (i = 0; i < 16; i++) {
1333 marker->process_APPn[i] = skip_variable;
1334 marker->length_limit_APPn[i] = 0;
1335 }
1336 marker->process_APPn[0] = get_interesting_appn;
1337 marker->process_APPn[14] = get_interesting_appn;
1338 /* Reset marker processing state */
1339 reset_marker_reader(cinfo);
1340 }
1341
1342
1343 /*
1344 * Control saving of COM and APPn markers into marker_list.
1345 */
1346
1347 #ifdef SAVE_MARKERS_SUPPORTED
1348
1349 GLOBAL(void)
jpeg_save_markers(j_decompress_ptr cinfo,int marker_code,unsigned int length_limit)1350 jpeg_save_markers (j_decompress_ptr cinfo, int marker_code,
1351 unsigned int length_limit)
1352 {
1353 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1354 long maxlength;
1355 jpeg_marker_parser_method processor;
1356
1357 /* Length limit mustn't be larger than what we can allocate
1358 * (should only be a concern in a 16-bit environment).
1359 */
1360 maxlength = cinfo->mem->max_alloc_chunk - SIZEOF(struct jpeg_marker_struct);
1361 if (((long) length_limit) > maxlength)
1362 length_limit = (unsigned int) maxlength;
1363
1364 /* Choose processor routine to use.
1365 * APP0/APP14 have special requirements.
1366 */
1367 if (length_limit) {
1368 processor = save_marker;
1369 /* If saving APP0/APP14, save at least enough for our internal use. */
1370 if (marker_code == (int) M_APP0 && length_limit < APP0_DATA_LEN)
1371 length_limit = APP0_DATA_LEN;
1372 else if (marker_code == (int) M_APP14 && length_limit < APP14_DATA_LEN)
1373 length_limit = APP14_DATA_LEN;
1374 } else {
1375 processor = skip_variable;
1376 /* If discarding APP0/APP14, use our regular on-the-fly processor. */
1377 if (marker_code == (int) M_APP0 || marker_code == (int) M_APP14)
1378 processor = get_interesting_appn;
1379 }
1380
1381 if (marker_code == (int) M_COM) {
1382 marker->process_COM = processor;
1383 marker->length_limit_COM = length_limit;
1384 } else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15) {
1385 marker->process_APPn[marker_code - (int) M_APP0] = processor;
1386 marker->length_limit_APPn[marker_code - (int) M_APP0] = length_limit;
1387 } else
1388 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
1389 }
1390
1391 #endif /* SAVE_MARKERS_SUPPORTED */
1392
1393
1394 /*
1395 * Install a special processing method for COM or APPn markers.
1396 */
1397
1398 GLOBAL(void)
jpeg_set_marker_processor(j_decompress_ptr cinfo,int marker_code,jpeg_marker_parser_method routine)1399 jpeg_set_marker_processor (j_decompress_ptr cinfo, int marker_code,
1400 jpeg_marker_parser_method routine)
1401 {
1402 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1403
1404 if (marker_code == (int) M_COM)
1405 marker->process_COM = routine;
1406 else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15)
1407 marker->process_APPn[marker_code - (int) M_APP0] = routine;
1408 else
1409 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
1410 }
1411