1 : /*
2 : * jdmarker.c
3 : *
4 : * Copyright (C) 1991-1998, Thomas G. Lane.
5 : * Copyright (C) 2012, D. R. Commander.
6 : * This file is part of the Independent JPEG Group's software.
7 : * For conditions of distribution and use, see the accompanying README file.
8 : *
9 : * This file contains routines to decode JPEG datastream markers.
10 : * Most of the complexity arises from our desire to support input
11 : * suspension: if not all of the data for a marker is available,
12 : * we must exit back to the application. On resumption, we reprocess
13 : * the marker.
14 : */
15 :
16 : #define JPEG_INTERNALS
17 : #include "jinclude.h"
18 : #include "jpeglib.h"
19 :
20 :
21 : typedef enum { /* JPEG marker codes */
22 : M_SOF0 = 0xc0,
23 : M_SOF1 = 0xc1,
24 : M_SOF2 = 0xc2,
25 : M_SOF3 = 0xc3,
26 :
27 : M_SOF5 = 0xc5,
28 : M_SOF6 = 0xc6,
29 : M_SOF7 = 0xc7,
30 :
31 : M_JPG = 0xc8,
32 : M_SOF9 = 0xc9,
33 : M_SOF10 = 0xca,
34 : M_SOF11 = 0xcb,
35 :
36 : M_SOF13 = 0xcd,
37 : M_SOF14 = 0xce,
38 : M_SOF15 = 0xcf,
39 :
40 : M_DHT = 0xc4,
41 :
42 : M_DAC = 0xcc,
43 :
44 : M_RST0 = 0xd0,
45 : M_RST1 = 0xd1,
46 : M_RST2 = 0xd2,
47 : M_RST3 = 0xd3,
48 : M_RST4 = 0xd4,
49 : M_RST5 = 0xd5,
50 : M_RST6 = 0xd6,
51 : M_RST7 = 0xd7,
52 :
53 : M_SOI = 0xd8,
54 : M_EOI = 0xd9,
55 : M_SOS = 0xda,
56 : M_DQT = 0xdb,
57 : M_DNL = 0xdc,
58 : M_DRI = 0xdd,
59 : M_DHP = 0xde,
60 : M_EXP = 0xdf,
61 :
62 : M_APP0 = 0xe0,
63 : M_APP1 = 0xe1,
64 : M_APP2 = 0xe2,
65 : M_APP3 = 0xe3,
66 : M_APP4 = 0xe4,
67 : M_APP5 = 0xe5,
68 : M_APP6 = 0xe6,
69 : M_APP7 = 0xe7,
70 : M_APP8 = 0xe8,
71 : M_APP9 = 0xe9,
72 : M_APP10 = 0xea,
73 : M_APP11 = 0xeb,
74 : M_APP12 = 0xec,
75 : M_APP13 = 0xed,
76 : M_APP14 = 0xee,
77 : M_APP15 = 0xef,
78 :
79 : M_JPG0 = 0xf0,
80 : M_JPG13 = 0xfd,
81 : M_COM = 0xfe,
82 :
83 : M_TEM = 0x01,
84 :
85 : M_ERROR = 0x100
86 : } JPEG_MARKER;
87 :
88 :
89 : /* Private state */
90 :
91 : typedef struct {
92 : struct jpeg_marker_reader pub; /* public fields */
93 :
94 : /* Application-overridable marker processing methods */
95 : jpeg_marker_parser_method process_COM;
96 : jpeg_marker_parser_method process_APPn[16];
97 :
98 : /* Limit on marker data length to save for each marker type */
99 : unsigned int length_limit_COM;
100 : unsigned int length_limit_APPn[16];
101 :
102 : /* Status of COM/APPn marker saving */
103 : jpeg_saved_marker_ptr cur_marker; /* NULL if not processing a marker */
104 : unsigned int bytes_read; /* data bytes read so far in marker */
105 : /* Note: cur_marker is not linked into marker_list until it's all read. */
106 : } my_marker_reader;
107 :
108 : typedef my_marker_reader * my_marker_ptr;
109 :
110 :
111 : /*
112 : * Macros for fetching data from the data source module.
113 : *
114 : * At all times, cinfo->src->next_input_byte and ->bytes_in_buffer reflect
115 : * the current restart point; we update them only when we have reached a
116 : * suitable place to restart if a suspension occurs.
117 : */
118 :
119 : /* Declare and initialize local copies of input pointer/count */
120 : #define INPUT_VARS(cinfo) \
121 : struct jpeg_source_mgr * datasrc = (cinfo)->src; \
122 : const JOCTET * next_input_byte = datasrc->next_input_byte; \
123 : size_t bytes_in_buffer = datasrc->bytes_in_buffer
124 :
125 : /* Unload the local copies --- do this only at a restart boundary */
126 : #define INPUT_SYNC(cinfo) \
127 : ( datasrc->next_input_byte = next_input_byte, \
128 : datasrc->bytes_in_buffer = bytes_in_buffer )
129 :
130 : /* Reload the local copies --- used only in MAKE_BYTE_AVAIL */
131 : #define INPUT_RELOAD(cinfo) \
132 : ( next_input_byte = datasrc->next_input_byte, \
133 : bytes_in_buffer = datasrc->bytes_in_buffer )
134 :
135 : /* Internal macro for INPUT_BYTE and INPUT_2BYTES: make a byte available.
136 : * Note we do *not* do INPUT_SYNC before calling fill_input_buffer,
137 : * but we must reload the local copies after a successful fill.
138 : */
139 : #define MAKE_BYTE_AVAIL(cinfo,action) \
140 : if (bytes_in_buffer == 0) { \
141 : if (! (*datasrc->fill_input_buffer) (cinfo)) \
142 : { action; } \
143 : INPUT_RELOAD(cinfo); \
144 : }
145 :
146 : /* Read a byte into variable V.
147 : * If must suspend, take the specified action (typically "return FALSE").
148 : */
149 : #define INPUT_BYTE(cinfo,V,action) \
150 : MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \
151 : bytes_in_buffer--; \
152 : V = GETJOCTET(*next_input_byte++); )
153 :
154 : /* As above, but read two bytes interpreted as an unsigned 16-bit integer.
155 : * V should be declared unsigned int or perhaps INT32.
156 : */
157 : #define INPUT_2BYTES(cinfo,V,action) \
158 : MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \
159 : bytes_in_buffer--; \
160 : V = ((unsigned int) GETJOCTET(*next_input_byte++)) << 8; \
161 : MAKE_BYTE_AVAIL(cinfo,action); \
162 : bytes_in_buffer--; \
163 : V += GETJOCTET(*next_input_byte++); )
164 :
165 :
166 : /*
167 : * Routines to process JPEG markers.
168 : *
169 : * Entry condition: JPEG marker itself has been read and its code saved
170 : * in cinfo->unread_marker; input restart point is just after the marker.
171 : *
172 : * Exit: if return TRUE, have read and processed any parameters, and have
173 : * updated the restart point to point after the parameters.
174 : * If return FALSE, was forced to suspend before reaching end of
175 : * marker parameters; restart point has not been moved. Same routine
176 : * will be called again after application supplies more input data.
177 : *
178 : * This approach to suspension assumes that all of a marker's parameters
179 : * can fit into a single input bufferload. This should hold for "normal"
180 : * markers. Some COM/APPn markers might have large parameter segments
181 : * that might not fit. If we are simply dropping such a marker, we use
182 : * skip_input_data to get past it, and thereby put the problem on the
183 : * source manager's shoulders. If we are saving the marker's contents
184 : * into memory, we use a slightly different convention: when forced to
185 : * suspend, the marker processor updates the restart point to the end of
186 : * what it's consumed (ie, the end of the buffer) before returning FALSE.
187 : * On resumption, cinfo->unread_marker still contains the marker code,
188 : * but the data source will point to the next chunk of marker data.
189 : * The marker processor must retain internal state to deal with this.
190 : *
191 : * Note that we don't bother to avoid duplicate trace messages if a
192 : * suspension occurs within marker parameters. Other side effects
193 : * require more care.
194 : */
195 :
196 :
197 : LOCAL(boolean)
198 5 : get_soi (j_decompress_ptr cinfo)
199 : /* Process an SOI marker */
200 : {
201 : int i;
202 :
203 5 : TRACEMS(cinfo, 1, JTRC_SOI);
204 :
205 5 : if (cinfo->marker->saw_SOI)
206 0 : ERREXIT(cinfo, JERR_SOI_DUPLICATE);
207 :
208 : /* Reset all parameters that are defined to be reset by SOI */
209 :
210 85 : for (i = 0; i < NUM_ARITH_TBLS; i++) {
211 80 : cinfo->arith_dc_L[i] = 0;
212 80 : cinfo->arith_dc_U[i] = 1;
213 80 : cinfo->arith_ac_K[i] = 5;
214 : }
215 5 : cinfo->restart_interval = 0;
216 :
217 : /* Set initial assumptions for colorspace etc */
218 :
219 5 : cinfo->jpeg_color_space = JCS_UNKNOWN;
220 5 : cinfo->CCIR601_sampling = FALSE; /* Assume non-CCIR sampling??? */
221 :
222 5 : cinfo->saw_JFIF_marker = FALSE;
223 5 : cinfo->JFIF_major_version = 1; /* set default JFIF APP0 values */
224 5 : cinfo->JFIF_minor_version = 1;
225 5 : cinfo->density_unit = 0;
226 5 : cinfo->X_density = 1;
227 5 : cinfo->Y_density = 1;
228 5 : cinfo->saw_Adobe_marker = FALSE;
229 5 : cinfo->Adobe_transform = 0;
230 :
231 5 : cinfo->marker->saw_SOI = TRUE;
232 :
233 5 : return TRUE;
234 : }
235 :
236 :
237 : LOCAL(boolean)
238 5 : get_sof (j_decompress_ptr cinfo, boolean is_prog, boolean is_arith)
239 : /* Process a SOFn marker */
240 : {
241 : INT32 length;
242 : int c, ci;
243 : jpeg_component_info * compptr;
244 5 : INPUT_VARS(cinfo);
245 :
246 5 : cinfo->progressive_mode = is_prog;
247 5 : cinfo->arith_code = is_arith;
248 :
249 5 : INPUT_2BYTES(cinfo, length, return FALSE);
250 :
251 5 : INPUT_BYTE(cinfo, cinfo->data_precision, return FALSE);
252 5 : INPUT_2BYTES(cinfo, cinfo->image_height, return FALSE);
253 5 : INPUT_2BYTES(cinfo, cinfo->image_width, return FALSE);
254 5 : INPUT_BYTE(cinfo, cinfo->num_components, return FALSE);
255 :
256 5 : length -= 8;
257 :
258 5 : TRACEMS4(cinfo, 1, JTRC_SOF, cinfo->unread_marker,
259 : (int) cinfo->image_width, (int) cinfo->image_height,
260 : cinfo->num_components);
261 :
262 5 : if (cinfo->marker->saw_SOF)
263 0 : ERREXIT(cinfo, JERR_SOF_DUPLICATE);
264 :
265 : /* We don't support files in which the image height is initially specified */
266 : /* as 0 and is later redefined by DNL. As long as we have to check that, */
267 : /* might as well have a general sanity check. */
268 5 : if (cinfo->image_height <= 0 || cinfo->image_width <= 0
269 5 : || cinfo->num_components <= 0)
270 0 : ERREXIT(cinfo, JERR_EMPTY_IMAGE);
271 :
272 5 : if (length != (cinfo->num_components * 3))
273 0 : ERREXIT(cinfo, JERR_BAD_LENGTH);
274 :
275 5 : if (cinfo->comp_info == NULL) /* do only once, even if suspend */
276 10 : cinfo->comp_info = (jpeg_component_info *) (*cinfo->mem->alloc_small)
277 10 : ((j_common_ptr) cinfo, JPOOL_IMAGE,
278 5 : cinfo->num_components * SIZEOF(jpeg_component_info));
279 :
280 25 : for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
281 15 : ci++, compptr++) {
282 15 : compptr->component_index = ci;
283 15 : INPUT_BYTE(cinfo, compptr->component_id, return FALSE);
284 15 : INPUT_BYTE(cinfo, c, return FALSE);
285 15 : compptr->h_samp_factor = (c >> 4) & 15;
286 15 : compptr->v_samp_factor = (c ) & 15;
287 15 : INPUT_BYTE(cinfo, compptr->quant_tbl_no, return FALSE);
288 :
289 15 : TRACEMS4(cinfo, 1, JTRC_SOF_COMPONENT,
290 : compptr->component_id, compptr->h_samp_factor,
291 : compptr->v_samp_factor, compptr->quant_tbl_no);
292 : }
293 :
294 5 : cinfo->marker->saw_SOF = TRUE;
295 :
296 5 : INPUT_SYNC(cinfo);
297 5 : return TRUE;
298 : }
299 :
300 :
301 : LOCAL(boolean)
302 5 : get_sos (j_decompress_ptr cinfo)
303 : /* Process a SOS marker */
304 : {
305 : INT32 length;
306 : int i, ci, n, c, cc;
307 : jpeg_component_info * compptr;
308 5 : INPUT_VARS(cinfo);
309 :
310 5 : if (! cinfo->marker->saw_SOF)
311 0 : ERREXIT(cinfo, JERR_SOS_NO_SOF);
312 :
313 5 : INPUT_2BYTES(cinfo, length, return FALSE);
314 :
315 5 : INPUT_BYTE(cinfo, n, return FALSE); /* Number of components */
316 :
317 5 : TRACEMS1(cinfo, 1, JTRC_SOS, n);
318 :
319 5 : if (length != (n * 2 + 6) || n < 1 || n > MAX_COMPS_IN_SCAN)
320 0 : ERREXIT(cinfo, JERR_BAD_LENGTH);
321 :
322 5 : cinfo->comps_in_scan = n;
323 :
324 : /* Collect the component-spec parameters */
325 :
326 20 : for (i = 0; i < cinfo->num_components; i++)
327 15 : cinfo->cur_comp_info[i] = NULL;
328 :
329 20 : for (i = 0; i < n; i++) {
330 15 : INPUT_BYTE(cinfo, cc, return FALSE);
331 15 : INPUT_BYTE(cinfo, c, return FALSE);
332 :
333 45 : for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
334 15 : ci++, compptr++) {
335 30 : if (cc == compptr->component_id && !cinfo->cur_comp_info[ci])
336 15 : goto id_found;
337 : }
338 :
339 0 : ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc);
340 :
341 : id_found:
342 :
343 15 : cinfo->cur_comp_info[i] = compptr;
344 15 : compptr->dc_tbl_no = (c >> 4) & 15;
345 15 : compptr->ac_tbl_no = (c ) & 15;
346 :
347 15 : TRACEMS3(cinfo, 1, JTRC_SOS_COMPONENT, cc,
348 : compptr->dc_tbl_no, compptr->ac_tbl_no);
349 : }
350 :
351 : /* Collect the additional scan parameters Ss, Se, Ah/Al. */
352 5 : INPUT_BYTE(cinfo, c, return FALSE);
353 5 : cinfo->Ss = c;
354 5 : INPUT_BYTE(cinfo, c, return FALSE);
355 5 : cinfo->Se = c;
356 5 : INPUT_BYTE(cinfo, c, return FALSE);
357 5 : cinfo->Ah = (c >> 4) & 15;
358 5 : cinfo->Al = (c ) & 15;
359 :
360 5 : TRACEMS4(cinfo, 1, JTRC_SOS_PARAMS, cinfo->Ss, cinfo->Se,
361 : cinfo->Ah, cinfo->Al);
362 :
363 : /* Prepare to scan data & restart markers */
364 5 : cinfo->marker->next_restart_num = 0;
365 :
366 : /* Count another SOS marker */
367 5 : cinfo->input_scan_number++;
368 :
369 5 : INPUT_SYNC(cinfo);
370 5 : return TRUE;
371 : }
372 :
373 :
374 : #ifdef D_ARITH_CODING_SUPPORTED
375 :
376 : LOCAL(boolean)
377 : get_dac (j_decompress_ptr cinfo)
378 : /* Process a DAC marker */
379 : {
380 : INT32 length;
381 : int index, val;
382 : INPUT_VARS(cinfo);
383 :
384 : INPUT_2BYTES(cinfo, length, return FALSE);
385 : length -= 2;
386 :
387 : while (length > 0) {
388 : INPUT_BYTE(cinfo, index, return FALSE);
389 : INPUT_BYTE(cinfo, val, return FALSE);
390 :
391 : length -= 2;
392 :
393 : TRACEMS2(cinfo, 1, JTRC_DAC, index, val);
394 :
395 : if (index < 0 || index >= (2*NUM_ARITH_TBLS))
396 : ERREXIT1(cinfo, JERR_DAC_INDEX, index);
397 :
398 : if (index >= NUM_ARITH_TBLS) { /* define AC table */
399 : cinfo->arith_ac_K[index-NUM_ARITH_TBLS] = (UINT8) val;
400 : } else { /* define DC table */
401 : cinfo->arith_dc_L[index] = (UINT8) (val & 0x0F);
402 : cinfo->arith_dc_U[index] = (UINT8) (val >> 4);
403 : if (cinfo->arith_dc_L[index] > cinfo->arith_dc_U[index])
404 : ERREXIT1(cinfo, JERR_DAC_VALUE, val);
405 : }
406 : }
407 :
408 : if (length != 0)
409 : ERREXIT(cinfo, JERR_BAD_LENGTH);
410 :
411 : INPUT_SYNC(cinfo);
412 : return TRUE;
413 : }
414 :
415 : #else /* ! D_ARITH_CODING_SUPPORTED */
416 :
417 : #define get_dac(cinfo) skip_variable(cinfo)
418 :
419 : #endif /* D_ARITH_CODING_SUPPORTED */
420 :
421 :
422 : LOCAL(boolean)
423 20 : get_dht (j_decompress_ptr cinfo)
424 : /* Process a DHT marker */
425 : {
426 : INT32 length;
427 : UINT8 bits[17];
428 : UINT8 huffval[256];
429 : int i, index, count;
430 : JHUFF_TBL **htblptr;
431 20 : INPUT_VARS(cinfo);
432 :
433 20 : INPUT_2BYTES(cinfo, length, return FALSE);
434 20 : length -= 2;
435 :
436 60 : while (length > 16) {
437 20 : INPUT_BYTE(cinfo, index, return FALSE);
438 :
439 20 : TRACEMS1(cinfo, 1, JTRC_DHT, index);
440 :
441 20 : bits[0] = 0;
442 20 : count = 0;
443 340 : for (i = 1; i <= 16; i++) {
444 320 : INPUT_BYTE(cinfo, bits[i], return FALSE);
445 320 : count += bits[i];
446 : }
447 :
448 20 : length -= 1 + 16;
449 :
450 20 : TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
451 : bits[1], bits[2], bits[3], bits[4],
452 : bits[5], bits[6], bits[7], bits[8]);
453 20 : TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
454 : bits[9], bits[10], bits[11], bits[12],
455 : bits[13], bits[14], bits[15], bits[16]);
456 :
457 : /* Here we just do minimal validation of the counts to avoid walking
458 : * off the end of our table space. jdhuff.c will check more carefully.
459 : */
460 20 : if (count > 256 || ((INT32) count) > length)
461 0 : ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
462 :
463 1760 : for (i = 0; i < count; i++)
464 1740 : INPUT_BYTE(cinfo, huffval[i], return FALSE);
465 :
466 20 : length -= count;
467 :
468 20 : if (index & 0x10) { /* AC table definition */
469 10 : index -= 0x10;
470 10 : htblptr = &cinfo->ac_huff_tbl_ptrs[index];
471 : } else { /* DC table definition */
472 10 : htblptr = &cinfo->dc_huff_tbl_ptrs[index];
473 : }
474 :
475 20 : if (index < 0 || index >= NUM_HUFF_TBLS)
476 0 : ERREXIT1(cinfo, JERR_DHT_INDEX, index);
477 :
478 20 : if (*htblptr == NULL)
479 20 : *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
480 :
481 20 : MEMCOPY((*htblptr)->bits, bits, SIZEOF((*htblptr)->bits));
482 20 : MEMCOPY((*htblptr)->huffval, huffval, SIZEOF((*htblptr)->huffval));
483 : }
484 :
485 20 : if (length != 0)
486 0 : ERREXIT(cinfo, JERR_BAD_LENGTH);
487 :
488 20 : INPUT_SYNC(cinfo);
489 20 : return TRUE;
490 : }
491 :
492 :
493 : LOCAL(boolean)
494 10 : get_dqt (j_decompress_ptr cinfo)
495 : /* Process a DQT marker */
496 : {
497 : INT32 length;
498 : int n, i, prec;
499 : unsigned int tmp;
500 : JQUANT_TBL *quant_ptr;
501 10 : INPUT_VARS(cinfo);
502 :
503 10 : INPUT_2BYTES(cinfo, length, return FALSE);
504 10 : length -= 2;
505 :
506 30 : while (length > 0) {
507 10 : INPUT_BYTE(cinfo, n, return FALSE);
508 10 : prec = n >> 4;
509 10 : n &= 0x0F;
510 :
511 10 : TRACEMS2(cinfo, 1, JTRC_DQT, n, prec);
512 :
513 10 : if (n >= NUM_QUANT_TBLS)
514 0 : ERREXIT1(cinfo, JERR_DQT_INDEX, n);
515 :
516 10 : if (cinfo->quant_tbl_ptrs[n] == NULL)
517 10 : cinfo->quant_tbl_ptrs[n] = jpeg_alloc_quant_table((j_common_ptr) cinfo);
518 10 : quant_ptr = cinfo->quant_tbl_ptrs[n];
519 :
520 650 : for (i = 0; i < DCTSIZE2; i++) {
521 640 : if (prec)
522 0 : INPUT_2BYTES(cinfo, tmp, return FALSE);
523 : else
524 640 : INPUT_BYTE(cinfo, tmp, return FALSE);
525 : /* We convert the zigzag-order table to natural array order. */
526 640 : quant_ptr->quantval[jpeg_natural_order[i]] = (UINT16) tmp;
527 : }
528 :
529 10 : if (cinfo->err->trace_level >= 2) {
530 0 : for (i = 0; i < DCTSIZE2; i += 8) {
531 0 : TRACEMS8(cinfo, 2, JTRC_QUANTVALS,
532 : quant_ptr->quantval[i], quant_ptr->quantval[i+1],
533 : quant_ptr->quantval[i+2], quant_ptr->quantval[i+3],
534 : quant_ptr->quantval[i+4], quant_ptr->quantval[i+5],
535 : quant_ptr->quantval[i+6], quant_ptr->quantval[i+7]);
536 : }
537 : }
538 :
539 10 : length -= DCTSIZE2+1;
540 10 : if (prec) length -= DCTSIZE2;
541 : }
542 :
543 10 : if (length != 0)
544 0 : ERREXIT(cinfo, JERR_BAD_LENGTH);
545 :
546 10 : INPUT_SYNC(cinfo);
547 10 : return TRUE;
548 : }
549 :
550 :
551 : LOCAL(boolean)
552 0 : get_dri (j_decompress_ptr cinfo)
553 : /* Process a DRI marker */
554 : {
555 : INT32 length;
556 : unsigned int tmp;
557 0 : INPUT_VARS(cinfo);
558 :
559 0 : INPUT_2BYTES(cinfo, length, return FALSE);
560 :
561 0 : if (length != 4)
562 0 : ERREXIT(cinfo, JERR_BAD_LENGTH);
563 :
564 0 : INPUT_2BYTES(cinfo, tmp, return FALSE);
565 :
566 0 : TRACEMS1(cinfo, 1, JTRC_DRI, tmp);
567 :
568 0 : cinfo->restart_interval = tmp;
569 :
570 0 : INPUT_SYNC(cinfo);
571 0 : return TRUE;
572 : }
573 :
574 :
575 : /*
576 : * Routines for processing APPn and COM markers.
577 : * These are either saved in memory or discarded, per application request.
578 : * APP0 and APP14 are specially checked to see if they are
579 : * JFIF and Adobe markers, respectively.
580 : */
581 :
582 : #define APP0_DATA_LEN 14 /* Length of interesting data in APP0 */
583 : #define APP14_DATA_LEN 12 /* Length of interesting data in APP14 */
584 : #define APPN_DATA_LEN 14 /* Must be the largest of the above!! */
585 :
586 :
587 : LOCAL(void)
588 5 : examine_app0 (j_decompress_ptr cinfo, JOCTET FAR * data,
589 : unsigned int datalen, INT32 remaining)
590 : /* Examine first few bytes from an APP0.
591 : * Take appropriate action if it is a JFIF marker.
592 : * datalen is # of bytes at data[], remaining is length of rest of marker data.
593 : */
594 : {
595 5 : INT32 totallen = (INT32) datalen + remaining;
596 :
597 10 : if (datalen >= APP0_DATA_LEN &&
598 10 : GETJOCTET(data[0]) == 0x4A &&
599 10 : GETJOCTET(data[1]) == 0x46 &&
600 10 : GETJOCTET(data[2]) == 0x49 &&
601 10 : GETJOCTET(data[3]) == 0x46 &&
602 5 : GETJOCTET(data[4]) == 0) {
603 : /* Found JFIF APP0 marker: save info */
604 5 : cinfo->saw_JFIF_marker = TRUE;
605 5 : cinfo->JFIF_major_version = GETJOCTET(data[5]);
606 5 : cinfo->JFIF_minor_version = GETJOCTET(data[6]);
607 5 : cinfo->density_unit = GETJOCTET(data[7]);
608 5 : cinfo->X_density = (GETJOCTET(data[8]) << 8) + GETJOCTET(data[9]);
609 5 : cinfo->Y_density = (GETJOCTET(data[10]) << 8) + GETJOCTET(data[11]);
610 : /* Check version.
611 : * Major version must be 1, anything else signals an incompatible change.
612 : * (We used to treat this as an error, but now it's a nonfatal warning,
613 : * because some bozo at Hijaak couldn't read the spec.)
614 : * Minor version should be 0..2, but process anyway if newer.
615 : */
616 5 : if (cinfo->JFIF_major_version != 1)
617 0 : WARNMS2(cinfo, JWRN_JFIF_MAJOR,
618 : cinfo->JFIF_major_version, cinfo->JFIF_minor_version);
619 : /* Generate trace messages */
620 5 : TRACEMS5(cinfo, 1, JTRC_JFIF,
621 : cinfo->JFIF_major_version, cinfo->JFIF_minor_version,
622 : cinfo->X_density, cinfo->Y_density, cinfo->density_unit);
623 : /* Validate thumbnail dimensions and issue appropriate messages */
624 5 : if (GETJOCTET(data[12]) | GETJOCTET(data[13]))
625 0 : TRACEMS2(cinfo, 1, JTRC_JFIF_THUMBNAIL,
626 : GETJOCTET(data[12]), GETJOCTET(data[13]));
627 5 : totallen -= APP0_DATA_LEN;
628 10 : if (totallen !=
629 5 : ((INT32)GETJOCTET(data[12]) * (INT32)GETJOCTET(data[13]) * (INT32) 3))
630 0 : TRACEMS1(cinfo, 1, JTRC_JFIF_BADTHUMBNAILSIZE, (int) totallen);
631 0 : } else if (datalen >= 6 &&
632 0 : GETJOCTET(data[0]) == 0x4A &&
633 0 : GETJOCTET(data[1]) == 0x46 &&
634 0 : GETJOCTET(data[2]) == 0x58 &&
635 0 : GETJOCTET(data[3]) == 0x58 &&
636 0 : GETJOCTET(data[4]) == 0) {
637 : /* Found JFIF "JFXX" extension APP0 marker */
638 : /* The library doesn't actually do anything with these,
639 : * but we try to produce a helpful trace message.
640 : */
641 0 : switch (GETJOCTET(data[5])) {
642 : case 0x10:
643 0 : TRACEMS1(cinfo, 1, JTRC_THUMB_JPEG, (int) totallen);
644 0 : break;
645 : case 0x11:
646 0 : TRACEMS1(cinfo, 1, JTRC_THUMB_PALETTE, (int) totallen);
647 0 : break;
648 : case 0x13:
649 0 : TRACEMS1(cinfo, 1, JTRC_THUMB_RGB, (int) totallen);
650 0 : break;
651 : default:
652 0 : TRACEMS2(cinfo, 1, JTRC_JFIF_EXTENSION,
653 : GETJOCTET(data[5]), (int) totallen);
654 0 : break;
655 : }
656 0 : } else {
657 : /* Start of APP0 does not match "JFIF" or "JFXX", or too short */
658 0 : TRACEMS1(cinfo, 1, JTRC_APP0, (int) totallen);
659 : }
660 5 : }
661 :
662 :
663 : LOCAL(void)
664 0 : examine_app14 (j_decompress_ptr cinfo, JOCTET FAR * data,
665 : unsigned int datalen, INT32 remaining)
666 : /* Examine first few bytes from an APP14.
667 : * Take appropriate action if it is an Adobe marker.
668 : * datalen is # of bytes at data[], remaining is length of rest of marker data.
669 : */
670 : {
671 : unsigned int version, flags0, flags1, transform;
672 :
673 0 : if (datalen >= APP14_DATA_LEN &&
674 0 : GETJOCTET(data[0]) == 0x41 &&
675 0 : GETJOCTET(data[1]) == 0x64 &&
676 0 : GETJOCTET(data[2]) == 0x6F &&
677 0 : GETJOCTET(data[3]) == 0x62 &&
678 0 : GETJOCTET(data[4]) == 0x65) {
679 : /* Found Adobe APP14 marker */
680 0 : version = (GETJOCTET(data[5]) << 8) + GETJOCTET(data[6]);
681 0 : flags0 = (GETJOCTET(data[7]) << 8) + GETJOCTET(data[8]);
682 0 : flags1 = (GETJOCTET(data[9]) << 8) + GETJOCTET(data[10]);
683 0 : transform = GETJOCTET(data[11]);
684 0 : TRACEMS4(cinfo, 1, JTRC_ADOBE, version, flags0, flags1, transform);
685 0 : cinfo->saw_Adobe_marker = TRUE;
686 0 : cinfo->Adobe_transform = (UINT8) transform;
687 : } else {
688 : /* Start of APP14 does not match "Adobe", or too short */
689 0 : TRACEMS1(cinfo, 1, JTRC_APP14, (int) (datalen + remaining));
690 : }
691 0 : }
692 :
693 :
694 : METHODDEF(boolean)
695 0 : get_interesting_appn (j_decompress_ptr cinfo)
696 : /* Process an APP0 or APP14 marker without saving it */
697 : {
698 : INT32 length;
699 : JOCTET b[APPN_DATA_LEN];
700 : unsigned int i, numtoread;
701 0 : INPUT_VARS(cinfo);
702 :
703 0 : INPUT_2BYTES(cinfo, length, return FALSE);
704 0 : length -= 2;
705 :
706 : /* get the interesting part of the marker data */
707 0 : if (length >= APPN_DATA_LEN)
708 0 : numtoread = APPN_DATA_LEN;
709 0 : else if (length > 0)
710 0 : numtoread = (unsigned int) length;
711 : else
712 0 : numtoread = 0;
713 0 : for (i = 0; i < numtoread; i++)
714 0 : INPUT_BYTE(cinfo, b[i], return FALSE);
715 0 : length -= numtoread;
716 :
717 : /* process it */
718 0 : switch (cinfo->unread_marker) {
719 : case M_APP0:
720 0 : examine_app0(cinfo, (JOCTET FAR *) b, numtoread, length);
721 0 : break;
722 : case M_APP14:
723 0 : examine_app14(cinfo, (JOCTET FAR *) b, numtoread, length);
724 0 : break;
725 : default:
726 : /* can't get here unless jpeg_save_markers chooses wrong processor */
727 0 : ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
728 0 : break;
729 : }
730 :
731 : /* skip any remaining data -- could be lots */
732 0 : INPUT_SYNC(cinfo);
733 0 : if (length > 0)
734 0 : (*cinfo->src->skip_input_data) (cinfo, (long) length);
735 :
736 0 : return TRUE;
737 : }
738 :
739 :
740 : #ifdef SAVE_MARKERS_SUPPORTED
741 :
742 : METHODDEF(boolean)
743 11 : save_marker (j_decompress_ptr cinfo)
744 : /* Save an APPn or COM marker into the marker list */
745 : {
746 11 : my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
747 11 : jpeg_saved_marker_ptr cur_marker = marker->cur_marker;
748 : unsigned int bytes_read, data_length;
749 : JOCTET FAR * data;
750 11 : INT32 length = 0;
751 11 : INPUT_VARS(cinfo);
752 :
753 11 : if (cur_marker == NULL) {
754 : /* begin reading a marker */
755 10 : INPUT_2BYTES(cinfo, length, return FALSE);
756 10 : length -= 2;
757 10 : if (length >= 0) { /* watch out for bogus length word */
758 : /* figure out how much we want to save */
759 : unsigned int limit;
760 10 : if (cinfo->unread_marker == (int) M_COM)
761 0 : limit = marker->length_limit_COM;
762 : else
763 10 : limit = marker->length_limit_APPn[cinfo->unread_marker - (int) M_APP0];
764 10 : if ((unsigned int) length < limit)
765 10 : limit = (unsigned int) length;
766 : /* allocate and initialize the marker item */
767 10 : cur_marker = (jpeg_saved_marker_ptr)
768 10 : (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
769 : SIZEOF(struct jpeg_marker_struct) + limit);
770 10 : cur_marker->next = NULL;
771 10 : cur_marker->marker = (UINT8) cinfo->unread_marker;
772 10 : cur_marker->original_length = (unsigned int) length;
773 10 : cur_marker->data_length = limit;
774 : /* data area is just beyond the jpeg_marker_struct */
775 10 : data = cur_marker->data = (JOCTET FAR *) (cur_marker + 1);
776 10 : marker->cur_marker = cur_marker;
777 10 : marker->bytes_read = 0;
778 10 : bytes_read = 0;
779 10 : data_length = limit;
780 : } else {
781 : /* deal with bogus length word */
782 0 : bytes_read = data_length = 0;
783 0 : data = NULL;
784 : }
785 : } else {
786 : /* resume reading a marker */
787 1 : bytes_read = marker->bytes_read;
788 1 : data_length = cur_marker->data_length;
789 1 : data = cur_marker->data + bytes_read;
790 : }
791 :
792 33 : while (bytes_read < data_length) {
793 12 : INPUT_SYNC(cinfo); /* move the restart point to here */
794 12 : marker->bytes_read = bytes_read;
795 : /* If there's not at least one byte in buffer, suspend */
796 12 : MAKE_BYTE_AVAIL(cinfo, return FALSE);
797 : /* Copy bytes with reasonable rapidity */
798 4495 : while (bytes_read < data_length && bytes_in_buffer > 0) {
799 4473 : *data++ = *next_input_byte++;
800 4473 : bytes_in_buffer--;
801 4473 : bytes_read++;
802 : }
803 : }
804 :
805 : /* Done reading what we want to read */
806 10 : if (cur_marker != NULL) { /* will be NULL if bogus length word */
807 : /* Add new marker to end of list */
808 10 : if (cinfo->marker_list == NULL) {
809 5 : cinfo->marker_list = cur_marker;
810 : } else {
811 5 : jpeg_saved_marker_ptr prev = cinfo->marker_list;
812 10 : while (prev->next != NULL)
813 0 : prev = prev->next;
814 5 : prev->next = cur_marker;
815 : }
816 : /* Reset pointer & calc remaining data length */
817 10 : data = cur_marker->data;
818 10 : length = cur_marker->original_length - data_length;
819 : }
820 : /* Reset to initial state for next marker */
821 10 : marker->cur_marker = NULL;
822 :
823 : /* Process the marker if interesting; else just make a generic trace msg */
824 10 : switch (cinfo->unread_marker) {
825 : case M_APP0:
826 5 : examine_app0(cinfo, data, data_length, length);
827 5 : break;
828 : case M_APP14:
829 0 : examine_app14(cinfo, data, data_length, length);
830 0 : break;
831 : default:
832 5 : TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker,
833 : (int) (data_length + length));
834 5 : break;
835 : }
836 :
837 : /* skip any remaining data -- could be lots */
838 10 : INPUT_SYNC(cinfo); /* do before skip_input_data */
839 10 : if (length > 0)
840 0 : (*cinfo->src->skip_input_data) (cinfo, (long) length);
841 :
842 10 : return TRUE;
843 : }
844 :
845 : #endif /* SAVE_MARKERS_SUPPORTED */
846 :
847 :
848 : METHODDEF(boolean)
849 3 : skip_variable (j_decompress_ptr cinfo)
850 : /* Skip over an unknown or uninteresting variable-length marker */
851 : {
852 : INT32 length;
853 3 : INPUT_VARS(cinfo);
854 :
855 3 : INPUT_2BYTES(cinfo, length, return FALSE);
856 3 : length -= 2;
857 :
858 3 : TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, (int) length);
859 :
860 3 : INPUT_SYNC(cinfo); /* do before skip_input_data */
861 3 : if (length > 0)
862 3 : (*cinfo->src->skip_input_data) (cinfo, (long) length);
863 :
864 3 : return TRUE;
865 : }
866 :
867 :
868 : /*
869 : * Find the next JPEG marker, save it in cinfo->unread_marker.
870 : * Returns FALSE if had to suspend before reaching a marker;
871 : * in that case cinfo->unread_marker is unchanged.
872 : *
873 : * Note that the result might not be a valid marker code,
874 : * but it will never be 0 or FF.
875 : */
876 :
877 : LOCAL(boolean)
878 55 : next_marker (j_decompress_ptr cinfo)
879 : {
880 : int c;
881 55 : INPUT_VARS(cinfo);
882 :
883 : for (;;) {
884 55 : INPUT_BYTE(cinfo, c, return FALSE);
885 : /* Skip any non-FF bytes.
886 : * This may look a bit inefficient, but it will not occur in a valid file.
887 : * We sync after each discarded byte so that a suspending data source
888 : * can discard the byte from its buffer.
889 : */
890 110 : while (c != 0xFF) {
891 0 : cinfo->marker->discarded_bytes++;
892 0 : INPUT_SYNC(cinfo);
893 0 : INPUT_BYTE(cinfo, c, return FALSE);
894 : }
895 : /* This loop swallows any duplicate FF bytes. Extra FFs are legal as
896 : * pad bytes, so don't count them in discarded_bytes. We assume there
897 : * will not be so many consecutive FF bytes as to overflow a suspending
898 : * data source's input buffer.
899 : */
900 : do {
901 55 : INPUT_BYTE(cinfo, c, return FALSE);
902 55 : } while (c == 0xFF);
903 55 : if (c != 0)
904 : break; /* found a valid marker, exit loop */
905 : /* Reach here if we found a stuffed-zero data sequence (FF/00).
906 : * Discard it and loop back to try again.
907 : */
908 0 : cinfo->marker->discarded_bytes += 2;
909 0 : INPUT_SYNC(cinfo);
910 0 : }
911 :
912 55 : if (cinfo->marker->discarded_bytes != 0) {
913 0 : WARNMS2(cinfo, JWRN_EXTRANEOUS_DATA, cinfo->marker->discarded_bytes, c);
914 0 : cinfo->marker->discarded_bytes = 0;
915 : }
916 :
917 55 : cinfo->unread_marker = c;
918 :
919 55 : INPUT_SYNC(cinfo);
920 55 : return TRUE;
921 : }
922 :
923 :
924 : LOCAL(boolean)
925 5 : first_marker (j_decompress_ptr cinfo)
926 : /* Like next_marker, but used to obtain the initial SOI marker. */
927 : /* For this marker, we do not allow preceding garbage or fill; otherwise,
928 : * we might well scan an entire input file before realizing it ain't JPEG.
929 : * If an application wants to process non-JFIF files, it must seek to the
930 : * SOI before calling the JPEG library.
931 : */
932 : {
933 : int c, c2;
934 5 : INPUT_VARS(cinfo);
935 :
936 5 : INPUT_BYTE(cinfo, c, return FALSE);
937 5 : INPUT_BYTE(cinfo, c2, return FALSE);
938 5 : if (c != 0xFF || c2 != (int) M_SOI)
939 0 : ERREXIT2(cinfo, JERR_NO_SOI, c, c2);
940 :
941 5 : cinfo->unread_marker = c2;
942 :
943 5 : INPUT_SYNC(cinfo);
944 5 : return TRUE;
945 : }
946 :
947 :
948 : /*
949 : * Read markers until SOS or EOI.
950 : *
951 : * Returns same codes as are defined for jpeg_consume_input:
952 : * JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
953 : */
954 :
955 : METHODDEF(int)
956 64 : read_markers (j_decompress_ptr cinfo)
957 : {
958 : /* Outer loop repeats once for each marker. */
959 : for (;;) {
960 : /* Collect the marker proper, unless we already did. */
961 : /* NB: first_marker() enforces the requirement that SOI appear first. */
962 64 : if (cinfo->unread_marker == 0) {
963 60 : if (! cinfo->marker->saw_SOI) {
964 5 : if (! first_marker(cinfo))
965 0 : return JPEG_SUSPENDED;
966 : } else {
967 55 : if (! next_marker(cinfo))
968 0 : return JPEG_SUSPENDED;
969 : }
970 : }
971 : /* At this point cinfo->unread_marker contains the marker code and the
972 : * input point is just past the marker proper, but before any parameters.
973 : * A suspension will cause us to return with this state still true.
974 : */
975 64 : switch (cinfo->unread_marker) {
976 : case M_SOI:
977 5 : if (! get_soi(cinfo))
978 0 : return JPEG_SUSPENDED;
979 5 : break;
980 :
981 : case M_SOF0: /* Baseline */
982 : case M_SOF1: /* Extended sequential, Huffman */
983 5 : if (! get_sof(cinfo, FALSE, FALSE))
984 0 : return JPEG_SUSPENDED;
985 5 : break;
986 :
987 : case M_SOF2: /* Progressive, Huffman */
988 0 : if (! get_sof(cinfo, TRUE, FALSE))
989 0 : return JPEG_SUSPENDED;
990 0 : break;
991 :
992 : case M_SOF9: /* Extended sequential, arithmetic */
993 0 : if (! get_sof(cinfo, FALSE, TRUE))
994 0 : return JPEG_SUSPENDED;
995 0 : break;
996 :
997 : case M_SOF10: /* Progressive, arithmetic */
998 0 : if (! get_sof(cinfo, TRUE, TRUE))
999 0 : return JPEG_SUSPENDED;
1000 0 : break;
1001 :
1002 : /* Currently unsupported SOFn types */
1003 : case M_SOF3: /* Lossless, Huffman */
1004 : case M_SOF5: /* Differential sequential, Huffman */
1005 : case M_SOF6: /* Differential progressive, Huffman */
1006 : case M_SOF7: /* Differential lossless, Huffman */
1007 : case M_JPG: /* Reserved for JPEG extensions */
1008 : case M_SOF11: /* Lossless, arithmetic */
1009 : case M_SOF13: /* Differential sequential, arithmetic */
1010 : case M_SOF14: /* Differential progressive, arithmetic */
1011 : case M_SOF15: /* Differential lossless, arithmetic */
1012 0 : ERREXIT1(cinfo, JERR_SOF_UNSUPPORTED, cinfo->unread_marker);
1013 0 : break;
1014 :
1015 : case M_SOS:
1016 5 : if (! get_sos(cinfo))
1017 0 : return JPEG_SUSPENDED;
1018 5 : cinfo->unread_marker = 0; /* processed the marker */
1019 5 : return JPEG_REACHED_SOS;
1020 :
1021 : case M_EOI:
1022 5 : TRACEMS(cinfo, 1, JTRC_EOI);
1023 5 : cinfo->unread_marker = 0; /* processed the marker */
1024 5 : return JPEG_REACHED_EOI;
1025 :
1026 : case M_DAC:
1027 0 : if (! get_dac(cinfo))
1028 0 : return JPEG_SUSPENDED;
1029 0 : break;
1030 :
1031 : case M_DHT:
1032 20 : if (! get_dht(cinfo))
1033 0 : return JPEG_SUSPENDED;
1034 20 : break;
1035 :
1036 : case M_DQT:
1037 10 : if (! get_dqt(cinfo))
1038 0 : return JPEG_SUSPENDED;
1039 10 : break;
1040 :
1041 : case M_DRI:
1042 0 : if (! get_dri(cinfo))
1043 0 : return JPEG_SUSPENDED;
1044 0 : break;
1045 :
1046 : case M_APP0:
1047 : case M_APP1:
1048 : case M_APP2:
1049 : case M_APP3:
1050 : case M_APP4:
1051 : case M_APP5:
1052 : case M_APP6:
1053 : case M_APP7:
1054 : case M_APP8:
1055 : case M_APP9:
1056 : case M_APP10:
1057 : case M_APP11:
1058 : case M_APP12:
1059 : case M_APP13:
1060 : case M_APP14:
1061 : case M_APP15:
1062 22 : if (! (*((my_marker_ptr) cinfo->marker)->process_APPn[
1063 11 : cinfo->unread_marker - (int) M_APP0]) (cinfo))
1064 1 : return JPEG_SUSPENDED;
1065 10 : break;
1066 :
1067 : case M_COM:
1068 3 : if (! (*((my_marker_ptr) cinfo->marker)->process_COM) (cinfo))
1069 0 : return JPEG_SUSPENDED;
1070 3 : break;
1071 :
1072 : case M_RST0: /* these are all parameterless */
1073 : case M_RST1:
1074 : case M_RST2:
1075 : case M_RST3:
1076 : case M_RST4:
1077 : case M_RST5:
1078 : case M_RST6:
1079 : case M_RST7:
1080 : case M_TEM:
1081 0 : TRACEMS1(cinfo, 1, JTRC_PARMLESS_MARKER, cinfo->unread_marker);
1082 0 : break;
1083 :
1084 : case M_DNL: /* Ignore DNL ... perhaps the wrong thing */
1085 0 : if (! skip_variable(cinfo))
1086 0 : return JPEG_SUSPENDED;
1087 0 : break;
1088 :
1089 : default: /* must be DHP, EXP, JPGn, or RESn */
1090 : /* For now, we treat the reserved markers as fatal errors since they are
1091 : * likely to be used to signal incompatible JPEG Part 3 extensions.
1092 : * Once the JPEG 3 version-number marker is well defined, this code
1093 : * ought to change!
1094 : */
1095 0 : ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
1096 0 : break;
1097 : }
1098 : /* Successfully processed marker, so reset state variable */
1099 53 : cinfo->unread_marker = 0;
1100 53 : } /* end loop */
1101 : }
1102 :
1103 :
1104 : /*
1105 : * Read a restart marker, which is expected to appear next in the datastream;
1106 : * if the marker is not there, take appropriate recovery action.
1107 : * Returns FALSE if suspension is required.
1108 : *
1109 : * This is called by the entropy decoder after it has read an appropriate
1110 : * number of MCUs. cinfo->unread_marker may be nonzero if the entropy decoder
1111 : * has already read a marker from the data source. Under normal conditions
1112 : * cinfo->unread_marker will be reset to 0 before returning; if not reset,
1113 : * it holds a marker which the decoder will be unable to read past.
1114 : */
1115 :
1116 : METHODDEF(boolean)
1117 0 : read_restart_marker (j_decompress_ptr cinfo)
1118 : {
1119 : /* Obtain a marker unless we already did. */
1120 : /* Note that next_marker will complain if it skips any data. */
1121 0 : if (cinfo->unread_marker == 0) {
1122 0 : if (! next_marker(cinfo))
1123 0 : return FALSE;
1124 : }
1125 :
1126 0 : if (cinfo->unread_marker ==
1127 0 : ((int) M_RST0 + cinfo->marker->next_restart_num)) {
1128 : /* Normal case --- swallow the marker and let entropy decoder continue */
1129 0 : TRACEMS1(cinfo, 3, JTRC_RST, cinfo->marker->next_restart_num);
1130 0 : cinfo->unread_marker = 0;
1131 : } else {
1132 : /* Uh-oh, the restart markers have been messed up. */
1133 : /* Let the data source manager determine how to resync. */
1134 0 : if (! (*cinfo->src->resync_to_restart) (cinfo,
1135 0 : cinfo->marker->next_restart_num))
1136 0 : return FALSE;
1137 : }
1138 :
1139 : /* Update next-restart state */
1140 0 : cinfo->marker->next_restart_num = (cinfo->marker->next_restart_num + 1) & 7;
1141 :
1142 0 : return TRUE;
1143 : }
1144 :
1145 :
1146 : /*
1147 : * This is the default resync_to_restart method for data source managers
1148 : * to use if they don't have any better approach. Some data source managers
1149 : * may be able to back up, or may have additional knowledge about the data
1150 : * which permits a more intelligent recovery strategy; such managers would
1151 : * presumably supply their own resync method.
1152 : *
1153 : * read_restart_marker calls resync_to_restart if it finds a marker other than
1154 : * the restart marker it was expecting. (This code is *not* used unless
1155 : * a nonzero restart interval has been declared.) cinfo->unread_marker is
1156 : * the marker code actually found (might be anything, except 0 or FF).
1157 : * The desired restart marker number (0..7) is passed as a parameter.
1158 : * This routine is supposed to apply whatever error recovery strategy seems
1159 : * appropriate in order to position the input stream to the next data segment.
1160 : * Note that cinfo->unread_marker is treated as a marker appearing before
1161 : * the current data-source input point; usually it should be reset to zero
1162 : * before returning.
1163 : * Returns FALSE if suspension is required.
1164 : *
1165 : * This implementation is substantially constrained by wanting to treat the
1166 : * input as a data stream; this means we can't back up. Therefore, we have
1167 : * only the following actions to work with:
1168 : * 1. Simply discard the marker and let the entropy decoder resume at next
1169 : * byte of file.
1170 : * 2. Read forward until we find another marker, discarding intervening
1171 : * data. (In theory we could look ahead within the current bufferload,
1172 : * without having to discard data if we don't find the desired marker.
1173 : * This idea is not implemented here, in part because it makes behavior
1174 : * dependent on buffer size and chance buffer-boundary positions.)
1175 : * 3. Leave the marker unread (by failing to zero cinfo->unread_marker).
1176 : * This will cause the entropy decoder to process an empty data segment,
1177 : * inserting dummy zeroes, and then we will reprocess the marker.
1178 : *
1179 : * #2 is appropriate if we think the desired marker lies ahead, while #3 is
1180 : * appropriate if the found marker is a future restart marker (indicating
1181 : * that we have missed the desired restart marker, probably because it got
1182 : * corrupted).
1183 : * We apply #2 or #3 if the found marker is a restart marker no more than
1184 : * two counts behind or ahead of the expected one. We also apply #2 if the
1185 : * found marker is not a legal JPEG marker code (it's certainly bogus data).
1186 : * If the found marker is a restart marker more than 2 counts away, we do #1
1187 : * (too much risk that the marker is erroneous; with luck we will be able to
1188 : * resync at some future point).
1189 : * For any valid non-restart JPEG marker, we apply #3. This keeps us from
1190 : * overrunning the end of a scan. An implementation limited to single-scan
1191 : * files might find it better to apply #2 for markers other than EOI, since
1192 : * any other marker would have to be bogus data in that case.
1193 : */
1194 :
1195 : GLOBAL(boolean)
1196 0 : jpeg_resync_to_restart (j_decompress_ptr cinfo, int desired)
1197 : {
1198 0 : int marker = cinfo->unread_marker;
1199 0 : int action = 1;
1200 :
1201 : /* Always put up a warning. */
1202 0 : WARNMS2(cinfo, JWRN_MUST_RESYNC, marker, desired);
1203 :
1204 : /* Outer loop handles repeated decision after scanning forward. */
1205 : for (;;) {
1206 0 : if (marker < (int) M_SOF0)
1207 0 : action = 2; /* invalid marker */
1208 0 : else if (marker < (int) M_RST0 || marker > (int) M_RST7)
1209 0 : action = 3; /* valid non-restart marker */
1210 : else {
1211 0 : if (marker == ((int) M_RST0 + ((desired+1) & 7)) ||
1212 0 : marker == ((int) M_RST0 + ((desired+2) & 7)))
1213 0 : action = 3; /* one of the next two expected restarts */
1214 0 : else if (marker == ((int) M_RST0 + ((desired-1) & 7)) ||
1215 0 : marker == ((int) M_RST0 + ((desired-2) & 7)))
1216 0 : action = 2; /* a prior restart, so advance */
1217 : else
1218 0 : action = 1; /* desired restart or too far away */
1219 : }
1220 0 : TRACEMS2(cinfo, 4, JTRC_RECOVERY_ACTION, marker, action);
1221 0 : switch (action) {
1222 : case 1:
1223 : /* Discard marker and let entropy decoder resume processing. */
1224 0 : cinfo->unread_marker = 0;
1225 0 : return TRUE;
1226 : case 2:
1227 : /* Scan to the next marker, and repeat the decision loop. */
1228 0 : if (! next_marker(cinfo))
1229 0 : return FALSE;
1230 0 : marker = cinfo->unread_marker;
1231 0 : break;
1232 : case 3:
1233 : /* Return without advancing past this marker. */
1234 : /* Entropy decoder will be forced to process an empty segment. */
1235 0 : return TRUE;
1236 : }
1237 0 : } /* end loop */
1238 : }
1239 :
1240 :
1241 : /*
1242 : * Reset marker processing state to begin a fresh datastream.
1243 : */
1244 :
1245 : METHODDEF(void)
1246 10 : reset_marker_reader (j_decompress_ptr cinfo)
1247 : {
1248 10 : my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1249 :
1250 10 : cinfo->comp_info = NULL; /* until allocated by get_sof */
1251 10 : cinfo->input_scan_number = 0; /* no SOS seen yet */
1252 10 : cinfo->unread_marker = 0; /* no pending marker */
1253 10 : marker->pub.saw_SOI = FALSE; /* set internal state too */
1254 10 : marker->pub.saw_SOF = FALSE;
1255 10 : marker->pub.discarded_bytes = 0;
1256 10 : marker->cur_marker = NULL;
1257 10 : }
1258 :
1259 :
1260 : /*
1261 : * Initialize the marker reader module.
1262 : * This is called only once, when the decompression object is created.
1263 : */
1264 :
1265 : GLOBAL(void)
1266 5 : jinit_marker_reader (j_decompress_ptr cinfo)
1267 : {
1268 : my_marker_ptr marker;
1269 : int i;
1270 :
1271 : /* Create subobject in permanent pool */
1272 5 : marker = (my_marker_ptr)
1273 5 : (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
1274 : SIZEOF(my_marker_reader));
1275 5 : cinfo->marker = (struct jpeg_marker_reader *) marker;
1276 : /* Initialize public method pointers */
1277 5 : marker->pub.reset_marker_reader = reset_marker_reader;
1278 5 : marker->pub.read_markers = read_markers;
1279 5 : marker->pub.read_restart_marker = read_restart_marker;
1280 : /* Initialize COM/APPn processing.
1281 : * By default, we examine and then discard APP0 and APP14,
1282 : * but simply discard COM and all other APPn.
1283 : */
1284 5 : marker->process_COM = skip_variable;
1285 5 : marker->length_limit_COM = 0;
1286 85 : for (i = 0; i < 16; i++) {
1287 80 : marker->process_APPn[i] = skip_variable;
1288 80 : marker->length_limit_APPn[i] = 0;
1289 : }
1290 5 : marker->process_APPn[0] = get_interesting_appn;
1291 5 : marker->process_APPn[14] = get_interesting_appn;
1292 : /* Reset marker processing state */
1293 5 : reset_marker_reader(cinfo);
1294 5 : }
1295 :
1296 :
1297 : /*
1298 : * Control saving of COM and APPn markers into marker_list.
1299 : */
1300 :
1301 : #ifdef SAVE_MARKERS_SUPPORTED
1302 :
1303 : GLOBAL(void)
1304 80 : jpeg_save_markers (j_decompress_ptr cinfo, int marker_code,
1305 : unsigned int length_limit)
1306 : {
1307 80 : my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1308 : long maxlength;
1309 : jpeg_marker_parser_method processor;
1310 :
1311 : /* Length limit mustn't be larger than what we can allocate
1312 : * (should only be a concern in a 16-bit environment).
1313 : */
1314 80 : maxlength = cinfo->mem->max_alloc_chunk - SIZEOF(struct jpeg_marker_struct);
1315 80 : if (((long) length_limit) > maxlength)
1316 0 : length_limit = (unsigned int) maxlength;
1317 :
1318 : /* Choose processor routine to use.
1319 : * APP0/APP14 have special requirements.
1320 : */
1321 80 : if (length_limit) {
1322 80 : processor = save_marker;
1323 : /* If saving APP0/APP14, save at least enough for our internal use. */
1324 80 : if (marker_code == (int) M_APP0 && length_limit < APP0_DATA_LEN)
1325 0 : length_limit = APP0_DATA_LEN;
1326 80 : else if (marker_code == (int) M_APP14 && length_limit < APP14_DATA_LEN)
1327 0 : length_limit = APP14_DATA_LEN;
1328 : } else {
1329 0 : processor = skip_variable;
1330 : /* If discarding APP0/APP14, use our regular on-the-fly processor. */
1331 0 : if (marker_code == (int) M_APP0 || marker_code == (int) M_APP14)
1332 0 : processor = get_interesting_appn;
1333 : }
1334 :
1335 80 : if (marker_code == (int) M_COM) {
1336 0 : marker->process_COM = processor;
1337 0 : marker->length_limit_COM = length_limit;
1338 80 : } else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15) {
1339 80 : marker->process_APPn[marker_code - (int) M_APP0] = processor;
1340 80 : marker->length_limit_APPn[marker_code - (int) M_APP0] = length_limit;
1341 : } else
1342 0 : ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
1343 80 : }
1344 :
1345 : #endif /* SAVE_MARKERS_SUPPORTED */
1346 :
1347 :
1348 : /*
1349 : * Install a special processing method for COM or APPn markers.
1350 : */
1351 :
1352 : GLOBAL(void)
1353 0 : jpeg_set_marker_processor (j_decompress_ptr cinfo, int marker_code,
1354 : jpeg_marker_parser_method routine)
1355 : {
1356 0 : my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1357 :
1358 0 : if (marker_code == (int) M_COM)
1359 0 : marker->process_COM = routine;
1360 0 : else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15)
1361 0 : marker->process_APPn[marker_code - (int) M_APP0] = routine;
1362 : else
1363 0 : ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
1364 0 : }
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