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jdmarker.c (41118B)
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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)
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)
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)
301 get_sos (j_decompress_ptr cinfo)
302 /* Process a SOS marker */
303 {
304 INT32 length;
305 int i, ci, n, c, cc;
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
347 /* Collect the additional scan parameters Ss, Se, Ah/Al. */
348 INPUT_BYTE(cinfo, c, return FALSE);
349 cinfo->Ss = c;
350 INPUT_BYTE(cinfo, c, return FALSE);
351 cinfo->Se = c;
352 INPUT_BYTE(cinfo, c, return FALSE);
353 cinfo->Ah = (c >> 4) & 15;
354 cinfo->Al = (c ) & 15;
355
356 TRACEMS4(cinfo, 1, JTRC_SOS_PARAMS, cinfo->Ss, cinfo->Se,
357 cinfo->Ah, cinfo->Al);
358
359 /* Prepare to scan data & restart markers */
360 cinfo->marker->next_restart_num = 0;
361
362 /* Count another SOS marker */
363 cinfo->input_scan_number++;
364
365 INPUT_SYNC(cinfo);
366 return TRUE;
367 }
368
369
370 #ifdef D_ARITH_CODING_SUPPORTED
371
372 LOCAL(boolean)
373 get_dac (j_decompress_ptr cinfo)
374 /* Process a DAC marker */
375 {
376 INT32 length;
377 int index, val;
378 INPUT_VARS(cinfo);
379
380 INPUT_2BYTES(cinfo, length, return FALSE);
381 length -= 2;
382
383 while (length > 0) {
384 INPUT_BYTE(cinfo, index, return FALSE);
385 INPUT_BYTE(cinfo, val, return FALSE);
386
387 length -= 2;
388
389 TRACEMS2(cinfo, 1, JTRC_DAC, index, val);
390
391 if (index < 0 || index >= (2*NUM_ARITH_TBLS))
392 ERREXIT1(cinfo, JERR_DAC_INDEX, index);
393
394 if (index >= NUM_ARITH_TBLS) { /* define AC table */
395 cinfo->arith_ac_K[index-NUM_ARITH_TBLS] = (UINT8) val;
396 } else { /* define DC table */
397 cinfo->arith_dc_L[index] = (UINT8) (val & 0x0F);
398 cinfo->arith_dc_U[index] = (UINT8) (val >> 4);
399 if (cinfo->arith_dc_L[index] > cinfo->arith_dc_U[index])
400 ERREXIT1(cinfo, JERR_DAC_VALUE, val);
401 }
402 }
403
404 if (length != 0)
405 ERREXIT(cinfo, JERR_BAD_LENGTH);
406
407 INPUT_SYNC(cinfo);
408 return TRUE;
409 }
410
411 #else /* ! D_ARITH_CODING_SUPPORTED */
412
413 #define get_dac(cinfo) skip_variable(cinfo)
414
415 #endif /* D_ARITH_CODING_SUPPORTED */
416
417
418 LOCAL(boolean)
419 get_dht (j_decompress_ptr cinfo)
420 /* Process a DHT marker */
421 {
422 INT32 length;
423 UINT8 bits[17];
424 UINT8 huffval[256];
425 int i, index, count;
426 JHUFF_TBL **htblptr;
427 INPUT_VARS(cinfo);
428
429 INPUT_2BYTES(cinfo, length, return FALSE);
430 length -= 2;
431
432 while (length > 16) {
433 INPUT_BYTE(cinfo, index, return FALSE);
434
435 TRACEMS1(cinfo, 1, JTRC_DHT, index);
436
437 bits[0] = 0;
438 count = 0;
439 for (i = 1; i <= 16; i++) {
440 INPUT_BYTE(cinfo, bits[i], return FALSE);
441 count += bits[i];
442 }
443
444 length -= 1 + 16;
445
446 TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
447 bits[1], bits[2], bits[3], bits[4],
448 bits[5], bits[6], bits[7], bits[8]);
449 TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
450 bits[9], bits[10], bits[11], bits[12],
451 bits[13], bits[14], bits[15], bits[16]);
452
453 /* Here we just do minimal validation of the counts to avoid walking
454 * off the end of our table space. jdhuff.c will check more carefully.
455 */
456 if (count > 256 || ((INT32) count) > length)
457 ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
458
459 for (i = 0; i < count; i++)
460 INPUT_BYTE(cinfo, huffval[i], return FALSE);
461
462 length -= count;
463
464 if (index & 0x10) { /* AC table definition */
465 index -= 0x10;
466 htblptr = &cinfo->ac_huff_tbl_ptrs[index];
467 } else { /* DC table definition */
468 htblptr = &cinfo->dc_huff_tbl_ptrs[index];
469 }
470
471 if (index < 0 || index >= NUM_HUFF_TBLS)
472 ERREXIT1(cinfo, JERR_DHT_INDEX, index);
473
474 if (*htblptr == NULL)
475 *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
476
477 MEMCOPY((*htblptr)->bits, bits, SIZEOF((*htblptr)->bits));
478 MEMCOPY((*htblptr)->huffval, huffval, SIZEOF((*htblptr)->huffval));
479 }
480
481 if (length != 0)
482 ERREXIT(cinfo, JERR_BAD_LENGTH);
483
484 INPUT_SYNC(cinfo);
485 return TRUE;
486 }
487
488
489 LOCAL(boolean)
490 get_dqt (j_decompress_ptr cinfo)
491 /* Process a DQT marker */
492 {
493 INT32 length;
494 int n, i, prec;
495 unsigned int tmp;
496 JQUANT_TBL *quant_ptr;
497 INPUT_VARS(cinfo);
498
499 INPUT_2BYTES(cinfo, length, return FALSE);
500 length -= 2;
501
502 while (length > 0) {
503 INPUT_BYTE(cinfo, n, return FALSE);
504 prec = n >> 4;
505 n &= 0x0F;
506
507 TRACEMS2(cinfo, 1, JTRC_DQT, n, prec);
508
509 if (n >= NUM_QUANT_TBLS)
510 ERREXIT1(cinfo, JERR_DQT_INDEX, n);
511
512 if (cinfo->quant_tbl_ptrs[n] == NULL)
513 cinfo->quant_tbl_ptrs[n] = jpeg_alloc_quant_table((j_common_ptr) cinfo);
514 quant_ptr = cinfo->quant_tbl_ptrs[n];
515
516 for (i = 0; i < DCTSIZE2; i++) {
517 if (prec)
518 INPUT_2BYTES(cinfo, tmp, return FALSE);
519 else
520 INPUT_BYTE(cinfo, tmp, return FALSE);
521 /* We convert the zigzag-order table to natural array order. */
522 quant_ptr->quantval[jpeg_natural_order[i]] = (UINT16) tmp;
523 }
524
525 if (cinfo->err->trace_level >= 2) {
526 for (i = 0; i < DCTSIZE2; i += 8) {
527 TRACEMS8(cinfo, 2, JTRC_QUANTVALS,
528 quant_ptr->quantval[i], quant_ptr->quantval[i+1],
529 quant_ptr->quantval[i+2], quant_ptr->quantval[i+3],
530 quant_ptr->quantval[i+4], quant_ptr->quantval[i+5],
531 quant_ptr->quantval[i+6], quant_ptr->quantval[i+7]);
532 }
533 }
534
535 length -= DCTSIZE2+1;
536 if (prec) length -= DCTSIZE2;
537 }
538
539 if (length != 0)
540 ERREXIT(cinfo, JERR_BAD_LENGTH);
541
542 INPUT_SYNC(cinfo);
543 return TRUE;
544 }
545
546
547 LOCAL(boolean)
548 get_dri (j_decompress_ptr cinfo)
549 /* Process a DRI marker */
550 {
551 INT32 length;
552 unsigned int tmp;
553 INPUT_VARS(cinfo);
554
555 INPUT_2BYTES(cinfo, length, return FALSE);
556
557 if (length != 4)
558 ERREXIT(cinfo, JERR_BAD_LENGTH);
559
560 INPUT_2BYTES(cinfo, tmp, return FALSE);
561
562 TRACEMS1(cinfo, 1, JTRC_DRI, tmp);
563
564 cinfo->restart_interval = tmp;
565
566 INPUT_SYNC(cinfo);
567 return TRUE;
568 }
569
570
571 /*
572 * Routines for processing APPn and COM markers.
573 * These are either saved in memory or discarded, per application request.
574 * APP0 and APP14 are specially checked to see if they are
575 * JFIF and Adobe markers, respectively.
576 */
577
578 #define APP0_DATA_LEN 14 /* Length of interesting data in APP0 */
579 #define APP14_DATA_LEN 12 /* Length of interesting data in APP14 */
580 #define APPN_DATA_LEN 14 /* Must be the largest of the above!! */
581
582
583 LOCAL(void)
584 examine_app0 (j_decompress_ptr cinfo, JOCTET FAR * data,
585 unsigned int datalen, INT32 remaining)
586 /* Examine first few bytes from an APP0.
587 * Take appropriate action if it is a JFIF marker.
588 * datalen is # of bytes at data[], remaining is length of rest of marker data.
589 */
590 {
591 INT32 totallen = (INT32) datalen + remaining;
592
593 if (datalen >= APP0_DATA_LEN &&
594 GETJOCTET(data[0]) == 0x4A &&
595 GETJOCTET(data[1]) == 0x46 &&
596 GETJOCTET(data[2]) == 0x49 &&
597 GETJOCTET(data[3]) == 0x46 &&
598 GETJOCTET(data[4]) == 0) {
599 /* Found JFIF APP0 marker: save info */
600 cinfo->saw_JFIF_marker = TRUE;
601 cinfo->JFIF_major_version = GETJOCTET(data[5]);
602 cinfo->JFIF_minor_version = GETJOCTET(data[6]);
603 cinfo->density_unit = GETJOCTET(data[7]);
604 cinfo->X_density = (GETJOCTET(data[8]) << 8) + GETJOCTET(data[9]);
605 cinfo->Y_density = (GETJOCTET(data[10]) << 8) + GETJOCTET(data[11]);
606 /* Check version.
607 * Major version must be 1, anything else signals an incompatible change.
608 * (We used to treat this as an error, but now it's a nonfatal warning,
609 * because some bozo at Hijaak couldn't read the spec.)
610 * Minor version should be 0..2, but process anyway if newer.
611 */
612 if (cinfo->JFIF_major_version != 1)
613 WARNMS2(cinfo, JWRN_JFIF_MAJOR,
614 cinfo->JFIF_major_version, cinfo->JFIF_minor_version);
615 /* Generate trace messages */
616 TRACEMS5(cinfo, 1, JTRC_JFIF,
617 cinfo->JFIF_major_version, cinfo->JFIF_minor_version,
618 cinfo->X_density, cinfo->Y_density, cinfo->density_unit);
619 /* Validate thumbnail dimensions and issue appropriate messages */
620 if (GETJOCTET(data[12]) | GETJOCTET(data[13]))
621 TRACEMS2(cinfo, 1, JTRC_JFIF_THUMBNAIL,
622 GETJOCTET(data[12]), GETJOCTET(data[13]));
623 totallen -= APP0_DATA_LEN;
624 if (totallen !=
625 ((INT32)GETJOCTET(data[12]) * (INT32)GETJOCTET(data[13]) * (INT32) 3))
626 TRACEMS1(cinfo, 1, JTRC_JFIF_BADTHUMBNAILSIZE, (int) totallen);
627 } else if (datalen >= 6 &&
628 GETJOCTET(data[0]) == 0x4A &&
629 GETJOCTET(data[1]) == 0x46 &&
630 GETJOCTET(data[2]) == 0x58 &&
631 GETJOCTET(data[3]) == 0x58 &&
632 GETJOCTET(data[4]) == 0) {
633 /* Found JFIF "JFXX" extension APP0 marker */
634 /* The library doesn't actually do anything with these,
635 * but we try to produce a helpful trace message.
636 */
637 switch (GETJOCTET(data[5])) {
638 case 0x10:
639 TRACEMS1(cinfo, 1, JTRC_THUMB_JPEG, (int) totallen);
640 break;
641 case 0x11:
642 TRACEMS1(cinfo, 1, JTRC_THUMB_PALETTE, (int) totallen);
643 break;
644 case 0x13:
645 TRACEMS1(cinfo, 1, JTRC_THUMB_RGB, (int) totallen);
646 break;
647 default:
648 TRACEMS2(cinfo, 1, JTRC_JFIF_EXTENSION,
649 GETJOCTET(data[5]), (int) totallen);
650 break;
651 }
652 } else {
653 /* Start of APP0 does not match "JFIF" or "JFXX", or too short */
654 TRACEMS1(cinfo, 1, JTRC_APP0, (int) totallen);
655 }
656 }
657
658
659 LOCAL(void)
660 examine_app14 (j_decompress_ptr cinfo, JOCTET FAR * data,
661 unsigned int datalen, INT32 remaining)
662 /* Examine first few bytes from an APP14.
663 * Take appropriate action if it is an Adobe marker.
664 * datalen is # of bytes at data[], remaining is length of rest of marker data.
665 */
666 {
667 unsigned int version, flags0, flags1, transform;
668
669 if (datalen >= APP14_DATA_LEN &&
670 GETJOCTET(data[0]) == 0x41 &&
671 GETJOCTET(data[1]) == 0x64 &&
672 GETJOCTET(data[2]) == 0x6F &&
673 GETJOCTET(data[3]) == 0x62 &&
674 GETJOCTET(data[4]) == 0x65) {
675 /* Found Adobe APP14 marker */
676 version = (GETJOCTET(data[5]) << 8) + GETJOCTET(data[6]);
677 flags0 = (GETJOCTET(data[7]) << 8) + GETJOCTET(data[8]);
678 flags1 = (GETJOCTET(data[9]) << 8) + GETJOCTET(data[10]);
679 transform = GETJOCTET(data[11]);
680 TRACEMS4(cinfo, 1, JTRC_ADOBE, version, flags0, flags1, transform);
681 cinfo->saw_Adobe_marker = TRUE;
682 cinfo->Adobe_transform = (UINT8) transform;
683 } else {
684 /* Start of APP14 does not match "Adobe", or too short */
685 TRACEMS1(cinfo, 1, JTRC_APP14, (int) (datalen + remaining));
686 }
687 }
688
689
690 METHODDEF(boolean)
691 get_interesting_appn (j_decompress_ptr cinfo)
692 /* Process an APP0 or APP14 marker without saving it */
693 {
694 INT32 length;
695 JOCTET b[APPN_DATA_LEN];
696 unsigned int i, numtoread;
697 INPUT_VARS(cinfo);
698
699 INPUT_2BYTES(cinfo, length, return FALSE);
700 length -= 2;
701
702 /* get the interesting part of the marker data */
703 if (length >= APPN_DATA_LEN)
704 numtoread = APPN_DATA_LEN;
705 else if (length > 0)
706 numtoread = (unsigned int) length;
707 else
708 numtoread = 0;
709 for (i = 0; i < numtoread; i++)
710 INPUT_BYTE(cinfo, b[i], return FALSE);
711 length -= numtoread;
712
713 /* process it */
714 switch (cinfo->unread_marker) {
715 case M_APP0:
716 examine_app0(cinfo, (JOCTET FAR *) b, numtoread, length);
717 break;
718 case M_APP14:
719 examine_app14(cinfo, (JOCTET FAR *) b, numtoread, length);
720 break;
721 default:
722 /* can't get here unless jpeg_save_markers chooses wrong processor */
723 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
724 break;
725 }
726
727 /* skip any remaining data -- could be lots */
728 INPUT_SYNC(cinfo);
729 if (length > 0)
730 (*cinfo->src->skip_input_data) (cinfo, (long) length);
731
732 return TRUE;
733 }
734
735
736 #ifdef SAVE_MARKERS_SUPPORTED
737
738 METHODDEF(boolean)
739 save_marker (j_decompress_ptr cinfo)
740 /* Save an APPn or COM marker into the marker list */
741 {
742 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
743 jpeg_saved_marker_ptr cur_marker = marker->cur_marker;
744 unsigned int bytes_read, data_length;
745 JOCTET FAR * data;
746 INT32 length = 0;
747 INPUT_VARS(cinfo);
748
749 if (cur_marker == NULL) {
750 /* begin reading a marker */
751 INPUT_2BYTES(cinfo, length, return FALSE);
752 length -= 2;
753 if (length >= 0) { /* watch out for bogus length word */
754 /* figure out how much we want to save */
755 unsigned int limit;
756 if (cinfo->unread_marker == (int) M_COM)
757 limit = marker->length_limit_COM;
758 else
759 limit = marker->length_limit_APPn[cinfo->unread_marker - (int) M_APP0];
760 if ((unsigned int) length < limit)
761 limit = (unsigned int) length;
762 /* allocate and initialize the marker item */
763 cur_marker = (jpeg_saved_marker_ptr)
764 (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
765 SIZEOF(struct jpeg_marker_struct) + limit);
766 cur_marker->next = NULL;
767 cur_marker->marker = (UINT8) cinfo->unread_marker;
768 cur_marker->original_length = (unsigned int) length;
769 cur_marker->data_length = limit;
770 /* data area is just beyond the jpeg_marker_struct */
771 data = cur_marker->data = (JOCTET FAR *) (cur_marker + 1);
772 marker->cur_marker = cur_marker;
773 marker->bytes_read = 0;
774 bytes_read = 0;
775 data_length = limit;
776 } else {
777 /* deal with bogus length word */
778 bytes_read = data_length = 0;
779 data = NULL;
780 }
781 } else {
782 /* resume reading a marker */
783 bytes_read = marker->bytes_read;
784 data_length = cur_marker->data_length;
785 data = cur_marker->data + bytes_read;
786 }
787
788 while (bytes_read < data_length) {
789 INPUT_SYNC(cinfo); /* move the restart point to here */
790 marker->bytes_read = bytes_read;
791 /* If there's not at least one byte in buffer, suspend */
792 MAKE_BYTE_AVAIL(cinfo, return FALSE);
793 /* Copy bytes with reasonable rapidity */
794 while (bytes_read < data_length && bytes_in_buffer > 0) {
795 *data++ = *next_input_byte++;
796 bytes_in_buffer--;
797 bytes_read++;
798 }
799 }
800
801 /* Done reading what we want to read */
802 if (cur_marker != NULL) { /* will be NULL if bogus length word */
803 /* Add new marker to end of list */
804 if (cinfo->marker_list == NULL) {
805 cinfo->marker_list = cur_marker;
806 } else {
807 jpeg_saved_marker_ptr prev = cinfo->marker_list;
808 while (prev->next != NULL)
809 prev = prev->next;
810 prev->next = cur_marker;
811 }
812 /* Reset pointer & calc remaining data length */
813 data = cur_marker->data;
814 length = cur_marker->original_length - data_length;
815 }
816 /* Reset to initial state for next marker */
817 marker->cur_marker = NULL;
818
819 /* Process the marker if interesting; else just make a generic trace msg */
820 switch (cinfo->unread_marker) {
821 case M_APP0:
822 examine_app0(cinfo, data, data_length, length);
823 break;
824 case M_APP14:
825 examine_app14(cinfo, data, data_length, length);
826 break;
827 default:
828 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker,
829 (int) (data_length + length));
830 break;
831 }
832
833 /* skip any remaining data -- could be lots */
834 INPUT_SYNC(cinfo); /* do before skip_input_data */
835 if (length > 0)
836 (*cinfo->src->skip_input_data) (cinfo, (long) length);
837
838 return TRUE;
839 }
840
841 #endif /* SAVE_MARKERS_SUPPORTED */
842
843
844 METHODDEF(boolean)
845 skip_variable (j_decompress_ptr cinfo)
846 /* Skip over an unknown or uninteresting variable-length marker */
847 {
848 INT32 length;
849 INPUT_VARS(cinfo);
850
851 INPUT_2BYTES(cinfo, length, return FALSE);
852 length -= 2;
853
854 TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, (int) length);
855
856 INPUT_SYNC(cinfo); /* do before skip_input_data */
857 if (length > 0)
858 (*cinfo->src->skip_input_data) (cinfo, (long) length);
859
860 return TRUE;
861 }
862
863
864 /*
865 * Find the next JPEG marker, save it in cinfo->unread_marker.
866 * Returns FALSE if had to suspend before reaching a marker;
867 * in that case cinfo->unread_marker is unchanged.
868 *
869 * Note that the result might not be a valid marker code,
870 * but it will never be 0 or FF.
871 */
872
873 LOCAL(boolean)
874 next_marker (j_decompress_ptr cinfo)
875 {
876 int c;
877 INPUT_VARS(cinfo);
878
879 for (;;) {
880 INPUT_BYTE(cinfo, c, return FALSE);
881 /* Skip any non-FF bytes.
882 * This may look a bit inefficient, but it will not occur in a valid file.
883 * We sync after each discarded byte so that a suspending data source
884 * can discard the byte from its buffer.
885 */
886 while (c != 0xFF) {
887 cinfo->marker->discarded_bytes++;
888 INPUT_SYNC(cinfo);
889 INPUT_BYTE(cinfo, c, return FALSE);
890 }
891 /* This loop swallows any duplicate FF bytes. Extra FFs are legal as
892 * pad bytes, so don't count them in discarded_bytes. We assume there
893 * will not be so many consecutive FF bytes as to overflow a suspending
894 * data source's input buffer.
895 */
896 do {
897 INPUT_BYTE(cinfo, c, return FALSE);
898 } while (c == 0xFF);
899 if (c != 0)
900 break; /* found a valid marker, exit loop */
901 /* Reach here if we found a stuffed-zero data sequence (FF/00).
902 * Discard it and loop back to try again.
903 */
904 cinfo->marker->discarded_bytes += 2;
905 INPUT_SYNC(cinfo);
906 }
907
908 if (cinfo->marker->discarded_bytes != 0) {
909 WARNMS2(cinfo, JWRN_EXTRANEOUS_DATA, cinfo->marker->discarded_bytes, c);
910 cinfo->marker->discarded_bytes = 0;
911 }
912
913 cinfo->unread_marker = c;
914
915 INPUT_SYNC(cinfo);
916 return TRUE;
917 }
918
919
920 LOCAL(boolean)
921 first_marker (j_decompress_ptr cinfo)
922 /* Like next_marker, but used to obtain the initial SOI marker. */
923 /* For this marker, we do not allow preceding garbage or fill; otherwise,
924 * we might well scan an entire input file before realizing it ain't JPEG.
925 * If an application wants to process non-JFIF files, it must seek to the
926 * SOI before calling the JPEG library.
927 */
928 {
929 int c, c2;
930 INPUT_VARS(cinfo);
931
932 INPUT_BYTE(cinfo, c, return FALSE);
933 INPUT_BYTE(cinfo, c2, return FALSE);
934 if (c != 0xFF || c2 != (int) M_SOI)
935 ERREXIT2(cinfo, JERR_NO_SOI, c, c2);
936
937 cinfo->unread_marker = c2;
938
939 INPUT_SYNC(cinfo);
940 return TRUE;
941 }
942
943
944 /*
945 * Read markers until SOS or EOI.
946 *
947 * Returns same codes as are defined for jpeg_consume_input:
948 * JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
949 */
950
951 METHODDEF(int)
952 read_markers (j_decompress_ptr cinfo)
953 {
954 /* Outer loop repeats once for each marker. */
955 for (;;) {
956 /* Collect the marker proper, unless we already did. */
957 /* NB: first_marker() enforces the requirement that SOI appear first. */
958 if (cinfo->unread_marker == 0) {
959 if (! cinfo->marker->saw_SOI) {
960 if (! first_marker(cinfo))
961 return JPEG_SUSPENDED;
962 } else {
963 if (! next_marker(cinfo))
964 return JPEG_SUSPENDED;
965 }
966 }
967 /* At this point cinfo->unread_marker contains the marker code and the
968 * input point is just past the marker proper, but before any parameters.
969 * A suspension will cause us to return with this state still true.
970 */
971 switch (cinfo->unread_marker) {
972 case M_SOI:
973 if (! get_soi(cinfo))
974 return JPEG_SUSPENDED;
975 break;
976
977 case M_SOF0: /* Baseline */
978 case M_SOF1: /* Extended sequential, Huffman */
979 if (! get_sof(cinfo, FALSE, FALSE))
980 return JPEG_SUSPENDED;
981 break;
982
983 case M_SOF2: /* Progressive, Huffman */
984 if (! get_sof(cinfo, TRUE, FALSE))
985 return JPEG_SUSPENDED;
986 break;
987
988 case M_SOF9: /* Extended sequential, arithmetic */
989 if (! get_sof(cinfo, FALSE, TRUE))
990 return JPEG_SUSPENDED;
991 break;
992
993 case M_SOF10: /* Progressive, arithmetic */
994 if (! get_sof(cinfo, TRUE, TRUE))
995 return JPEG_SUSPENDED;
996 break;
997
998 /* Currently unsupported SOFn types */
999 case M_SOF3: /* Lossless, Huffman */
1000 case M_SOF5: /* Differential sequential, Huffman */
1001 case M_SOF6: /* Differential progressive, Huffman */
1002 case M_SOF7: /* Differential lossless, Huffman */
1003 case M_JPG: /* Reserved for JPEG extensions */
1004 case M_SOF11: /* Lossless, arithmetic */
1005 case M_SOF13: /* Differential sequential, arithmetic */
1006 case M_SOF14: /* Differential progressive, arithmetic */
1007 case M_SOF15: /* Differential lossless, arithmetic */
1008 ERREXIT1(cinfo, JERR_SOF_UNSUPPORTED, cinfo->unread_marker);
1009 break;
1010
1011 case M_SOS:
1012 if (! get_sos(cinfo))
1013 return JPEG_SUSPENDED;
1014 cinfo->unread_marker = 0; /* processed the marker */
1015 return JPEG_REACHED_SOS;
1016
1017 case M_EOI:
1018 TRACEMS(cinfo, 1, JTRC_EOI);
1019 cinfo->unread_marker = 0; /* processed the marker */
1020 return JPEG_REACHED_EOI;
1021
1022 case M_DAC:
1023 if (! get_dac(cinfo))
1024 return JPEG_SUSPENDED;
1025 break;
1026
1027 case M_DHT:
1028 if (! get_dht(cinfo))
1029 return JPEG_SUSPENDED;
1030 break;
1031
1032 case M_DQT:
1033 if (! get_dqt(cinfo))
1034 return JPEG_SUSPENDED;
1035 break;
1036
1037 case M_DRI:
1038 if (! get_dri(cinfo))
1039 return JPEG_SUSPENDED;
1040 break;
1041
1042 case M_APP0:
1043 case M_APP1:
1044 case M_APP2:
1045 case M_APP3:
1046 case M_APP4:
1047 case M_APP5:
1048 case M_APP6:
1049 case M_APP7:
1050 case M_APP8:
1051 case M_APP9:
1052 case M_APP10:
1053 case M_APP11:
1054 case M_APP12:
1055 case M_APP13:
1056 case M_APP14:
1057 case M_APP15:
1058 if (! (*((my_marker_ptr) cinfo->marker)->process_APPn[
1059 cinfo->unread_marker - (int) M_APP0]) (cinfo))
1060 return JPEG_SUSPENDED;
1061 break;
1062
1063 case M_COM:
1064 if (! (*((my_marker_ptr) cinfo->marker)->process_COM) (cinfo))
1065 return JPEG_SUSPENDED;
1066 break;
1067
1068 case M_RST0: /* these are all parameterless */
1069 case M_RST1:
1070 case M_RST2:
1071 case M_RST3:
1072 case M_RST4:
1073 case M_RST5:
1074 case M_RST6:
1075 case M_RST7:
1076 case M_TEM:
1077 TRACEMS1(cinfo, 1, JTRC_PARMLESS_MARKER, cinfo->unread_marker);
1078 break;
1079
1080 case M_DNL: /* Ignore DNL ... perhaps the wrong thing */
1081 if (! skip_variable(cinfo))
1082 return JPEG_SUSPENDED;
1083 break;
1084
1085 default: /* must be DHP, EXP, JPGn, or RESn */
1086 /* For now, we treat the reserved markers as fatal errors since they are
1087 * likely to be used to signal incompatible JPEG Part 3 extensions.
1088 * Once the JPEG 3 version-number marker is well defined, this code
1089 * ought to change!
1090 */
1091 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
1092 break;
1093 }
1094 /* Successfully processed marker, so reset state variable */
1095 cinfo->unread_marker = 0;
1096 } /* end loop */
1097 }
1098
1099
1100 /*
1101 * Read a restart marker, which is expected to appear next in the datastream;
1102 * if the marker is not there, take appropriate recovery action.
1103 * Returns FALSE if suspension is required.
1104 *
1105 * This is called by the entropy decoder after it has read an appropriate
1106 * number of MCUs. cinfo->unread_marker may be nonzero if the entropy decoder
1107 * has already read a marker from the data source. Under normal conditions
1108 * cinfo->unread_marker will be reset to 0 before returning; if not reset,
1109 * it holds a marker which the decoder will be unable to read past.
1110 */
1111
1112 METHODDEF(boolean)
1113 read_restart_marker (j_decompress_ptr cinfo)
1114 {
1115 /* Obtain a marker unless we already did. */
1116 /* Note that next_marker will complain if it skips any data. */
1117 if (cinfo->unread_marker == 0) {
1118 if (! next_marker(cinfo))
1119 return FALSE;
1120 }
1121
1122 if (cinfo->unread_marker ==
1123 ((int) M_RST0 + cinfo->marker->next_restart_num)) {
1124 /* Normal case --- swallow the marker and let entropy decoder continue */
1125 TRACEMS1(cinfo, 3, JTRC_RST, cinfo->marker->next_restart_num);
1126 cinfo->unread_marker = 0;
1127 } else {
1128 /* Uh-oh, the restart markers have been messed up. */
1129 /* Let the data source manager determine how to resync. */
1130 if (! (*cinfo->src->resync_to_restart) (cinfo,
1131 cinfo->marker->next_restart_num))
1132 return FALSE;
1133 }
1134
1135 /* Update next-restart state */
1136 cinfo->marker->next_restart_num = (cinfo->marker->next_restart_num + 1) & 7;
1137
1138 return TRUE;
1139 }
1140
1141
1142 /*
1143 * This is the default resync_to_restart method for data source managers
1144 * to use if they don't have any better approach. Some data source managers
1145 * may be able to back up, or may have additional knowledge about the data
1146 * which permits a more intelligent recovery strategy; such managers would
1147 * presumably supply their own resync method.
1148 *
1149 * read_restart_marker calls resync_to_restart if it finds a marker other than
1150 * the restart marker it was expecting. (This code is *not* used unless
1151 * a nonzero restart interval has been declared.) cinfo->unread_marker is
1152 * the marker code actually found (might be anything, except 0 or FF).
1153 * The desired restart marker number (0..7) is passed as a parameter.
1154 * This routine is supposed to apply whatever error recovery strategy seems
1155 * appropriate in order to position the input stream to the next data segment.
1156 * Note that cinfo->unread_marker is treated as a marker appearing before
1157 * the current data-source input point; usually it should be reset to zero
1158 * before returning.
1159 * Returns FALSE if suspension is required.
1160 *
1161 * This implementation is substantially constrained by wanting to treat the
1162 * input as a data stream; this means we can't back up. Therefore, we have
1163 * only the following actions to work with:
1164 * 1. Simply discard the marker and let the entropy decoder resume at next
1165 * byte of file.
1166 * 2. Read forward until we find another marker, discarding intervening
1167 * data. (In theory we could look ahead within the current bufferload,
1168 * without having to discard data if we don't find the desired marker.
1169 * This idea is not implemented here, in part because it makes behavior
1170 * dependent on buffer size and chance buffer-boundary positions.)
1171 * 3. Leave the marker unread (by failing to zero cinfo->unread_marker).
1172 * This will cause the entropy decoder to process an empty data segment,
1173 * inserting dummy zeroes, and then we will reprocess the marker.
1174 *
1175 * #2 is appropriate if we think the desired marker lies ahead, while #3 is
1176 * appropriate if the found marker is a future restart marker (indicating
1177 * that we have missed the desired restart marker, probably because it got
1178 * corrupted).
1179 * We apply #2 or #3 if the found marker is a restart marker no more than
1180 * two counts behind or ahead of the expected one. We also apply #2 if the
1181 * found marker is not a legal JPEG marker code (it's certainly bogus data).
1182 * If the found marker is a restart marker more than 2 counts away, we do #1
1183 * (too much risk that the marker is erroneous; with luck we will be able to
1184 * resync at some future point).
1185 * For any valid non-restart JPEG marker, we apply #3. This keeps us from
1186 * overrunning the end of a scan. An implementation limited to single-scan
1187 * files might find it better to apply #2 for markers other than EOI, since
1188 * any other marker would have to be bogus data in that case.
1189 */
1190
1191 GLOBAL(boolean)
1192 jpeg_resync_to_restart (j_decompress_ptr cinfo, int desired)
1193 {
1194 int marker = cinfo->unread_marker;
1195 int action = 1;
1196
1197 /* Always put up a warning. */
1198 WARNMS2(cinfo, JWRN_MUST_RESYNC, marker, desired);
1199
1200 /* Outer loop handles repeated decision after scanning forward. */
1201 for (;;) {
1202 if (marker < (int) M_SOF0)
1203 action = 2; /* invalid marker */
1204 else if (marker < (int) M_RST0 || marker > (int) M_RST7)
1205 action = 3; /* valid non-restart marker */
1206 else {
1207 if (marker == ((int) M_RST0 + ((desired+1) & 7)) ||
1208 marker == ((int) M_RST0 + ((desired+2) & 7)))
1209 action = 3; /* one of the next two expected restarts */
1210 else if (marker == ((int) M_RST0 + ((desired-1) & 7)) ||
1211 marker == ((int) M_RST0 + ((desired-2) & 7)))
1212 action = 2; /* a prior restart, so advance */
1213 else
1214 action = 1; /* desired restart or too far away */
1215 }
1216 TRACEMS2(cinfo, 4, JTRC_RECOVERY_ACTION, marker, action);
1217 switch (action) {
1218 case 1:
1219 /* Discard marker and let entropy decoder resume processing. */
1220 cinfo->unread_marker = 0;
1221 return TRUE;
1222 case 2:
1223 /* Scan to the next marker, and repeat the decision loop. */
1224 if (! next_marker(cinfo))
1225 return FALSE;
1226 marker = cinfo->unread_marker;
1227 break;
1228 case 3:
1229 /* Return without advancing past this marker. */
1230 /* Entropy decoder will be forced to process an empty segment. */
1231 return TRUE;
1232 }
1233 } /* end loop */
1234 }
1235
1236
1237 /*
1238 * Reset marker processing state to begin a fresh datastream.
1239 */
1240
1241 METHODDEF(void)
1242 reset_marker_reader (j_decompress_ptr cinfo)
1243 {
1244 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1245
1246 cinfo->comp_info = NULL; /* until allocated by get_sof */
1247 cinfo->input_scan_number = 0; /* no SOS seen yet */
1248 cinfo->unread_marker = 0; /* no pending marker */
1249 marker->pub.saw_SOI = FALSE; /* set internal state too */
1250 marker->pub.saw_SOF = FALSE;
1251 marker->pub.discarded_bytes = 0;
1252 marker->cur_marker = NULL;
1253 }
1254
1255
1256 /*
1257 * Initialize the marker reader module.
1258 * This is called only once, when the decompression object is created.
1259 */
1260
1261 GLOBAL(void)
1262 jinit_marker_reader (j_decompress_ptr cinfo)
1263 {
1264 my_marker_ptr marker;
1265 int i;
1266
1267 /* Create subobject in permanent pool */
1268 marker = (my_marker_ptr)
1269 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
1270 SIZEOF(my_marker_reader));
1271 cinfo->marker = (struct jpeg_marker_reader *) marker;
1272 /* Initialize public method pointers */
1273 marker->pub.reset_marker_reader = reset_marker_reader;
1274 marker->pub.read_markers = read_markers;
1275 marker->pub.read_restart_marker = read_restart_marker;
1276 /* Initialize COM/APPn processing.
1277 * By default, we examine and then discard APP0 and APP14,
1278 * but simply discard COM and all other APPn.
1279 */
1280 marker->process_COM = skip_variable;
1281 marker->length_limit_COM = 0;
1282 for (i = 0; i < 16; i++) {
1283 marker->process_APPn[i] = skip_variable;
1284 marker->length_limit_APPn[i] = 0;
1285 }
1286 marker->process_APPn[0] = get_interesting_appn;
1287 marker->process_APPn[14] = get_interesting_appn;
1288 /* Reset marker processing state */
1289 reset_marker_reader(cinfo);
1290 }
1291
1292
1293 /*
1294 * Control saving of COM and APPn markers into marker_list.
1295 */
1296
1297 #ifdef SAVE_MARKERS_SUPPORTED
1298
1299 GLOBAL(void)
1300 jpeg_save_markers (j_decompress_ptr cinfo, int marker_code,
1301 unsigned int length_limit)
1302 {
1303 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1304 long maxlength;
1305 jpeg_marker_parser_method processor;
1306
1307 /* Length limit mustn't be larger than what we can allocate
1308 * (should only be a concern in a 16-bit environment).
1309 */
1310 maxlength = cinfo->mem->max_alloc_chunk - SIZEOF(struct jpeg_marker_struct);
1311 if (((long) length_limit) > maxlength)
1312 length_limit = (unsigned int) maxlength;
1313
1314 /* Choose processor routine to use.
1315 * APP0/APP14 have special requirements.
1316 */
1317 if (length_limit) {
1318 processor = save_marker;
1319 /* If saving APP0/APP14, save at least enough for our internal use. */
1320 if (marker_code == (int) M_APP0 && length_limit < APP0_DATA_LEN)
1321 length_limit = APP0_DATA_LEN;
1322 else if (marker_code == (int) M_APP14 && length_limit < APP14_DATA_LEN)
1323 length_limit = APP14_DATA_LEN;
1324 } else {
1325 processor = skip_variable;
1326 /* If discarding APP0/APP14, use our regular on-the-fly processor. */
1327 if (marker_code == (int) M_APP0 || marker_code == (int) M_APP14)
1328 processor = get_interesting_appn;
1329 }
1330
1331 if (marker_code == (int) M_COM) {
1332 marker->process_COM = processor;
1333 marker->length_limit_COM = length_limit;
1334 } else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15) {
1335 marker->process_APPn[marker_code - (int) M_APP0] = processor;
1336 marker->length_limit_APPn[marker_code - (int) M_APP0] = length_limit;
1337 } else
1338 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
1339 }
1340
1341 #endif /* SAVE_MARKERS_SUPPORTED */
1342
1343
1344 /*
1345 * Install a special processing method for COM or APPn markers.
1346 */
1347
1348 GLOBAL(void)
1349 jpeg_set_marker_processor (j_decompress_ptr cinfo, int marker_code,
1350 jpeg_marker_parser_method routine)
1351 {
1352 my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1353
1354 if (marker_code == (int) M_COM)
1355 marker->process_COM = routine;
1356 else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15)
1357 marker->process_APPn[marker_code - (int) M_APP0] = routine;
1358 else
1359 ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
1360 }