source: trunk/libjpeg/jdmarker.c @ 15

Last change on this file since 15 was 15, checked in by Eugene Romanenko, 15 years ago

needed libs update

File size: 41.5 KB
Line 
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
20typedef 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
90typedef 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
107typedef 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
196LOCAL(boolean)
197get_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
236LOCAL(boolean)
237get_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
300LOCAL(boolean)
301get_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
372LOCAL(boolean)
373get_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
418LOCAL(boolean)
419get_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
489LOCAL(boolean)
490get_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
547LOCAL(boolean)
548get_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
583LOCAL(void)
584examine_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
659LOCAL(void)
660examine_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
690METHODDEF(boolean)
691get_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
738METHODDEF(boolean)
739save_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
844METHODDEF(boolean)
845skip_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
873LOCAL(boolean)
874next_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
920LOCAL(boolean)
921first_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
951METHODDEF(int)
952read_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
1112METHODDEF(boolean)
1113read_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
1191GLOBAL(boolean)
1192jpeg_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
1241METHODDEF(void)
1242reset_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
1261GLOBAL(void)
1262jinit_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
1299GLOBAL(void)
1300jpeg_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
1348GLOBAL(void)
1349jpeg_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}
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