source: rtems-graphics-toolkit/jpeg-8d/jdmarker.c @ 86b99f7

Last change on this file since 86b99f7 was 86b99f7, checked in by Alexandru-Sever Horin <alex.sever.h@…>, on Aug 1, 2012 at 10:40:32 PM

Added jpeg-8d version. Made modifications to compile for RTEMS, without man or binaries

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1/*
2 * jdmarker.c
3 *
4 * Copyright (C) 1991-1998, Thomas G. Lane.
5 * Modified 2009 by Guido Vollbeding.
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
21typedef 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
91typedef 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
108typedef 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
197LOCAL(boolean)
198get_soi (j_decompress_ptr cinfo)
199/* Process an SOI marker */
200{
201  int i;
202 
203  TRACEMS(cinfo, 1, JTRC_SOI);
204
205  if (cinfo->marker->saw_SOI)
206    ERREXIT(cinfo, JERR_SOI_DUPLICATE);
207
208  /* Reset all parameters that are defined to be reset by SOI */
209
210  for (i = 0; i < NUM_ARITH_TBLS; i++) {
211    cinfo->arith_dc_L[i] = 0;
212    cinfo->arith_dc_U[i] = 1;
213    cinfo->arith_ac_K[i] = 5;
214  }
215  cinfo->restart_interval = 0;
216
217  /* Set initial assumptions for colorspace etc */
218
219  cinfo->jpeg_color_space = JCS_UNKNOWN;
220  cinfo->CCIR601_sampling = FALSE; /* Assume non-CCIR sampling??? */
221
222  cinfo->saw_JFIF_marker = FALSE;
223  cinfo->JFIF_major_version = 1; /* set default JFIF APP0 values */
224  cinfo->JFIF_minor_version = 1;
225  cinfo->density_unit = 0;
226  cinfo->X_density = 1;
227  cinfo->Y_density = 1;
228  cinfo->saw_Adobe_marker = FALSE;
229  cinfo->Adobe_transform = 0;
230
231  cinfo->marker->saw_SOI = TRUE;
232
233  return TRUE;
234}
235
236
237LOCAL(boolean)
238get_sof (j_decompress_ptr cinfo, boolean is_baseline, boolean is_prog,
239         boolean is_arith)
240/* Process a SOFn marker */
241{
242  INT32 length;
243  int c, ci;
244  jpeg_component_info * compptr;
245  INPUT_VARS(cinfo);
246
247  cinfo->is_baseline = is_baseline;
248  cinfo->progressive_mode = is_prog;
249  cinfo->arith_code = is_arith;
250
251  INPUT_2BYTES(cinfo, length, return FALSE);
252
253  INPUT_BYTE(cinfo, cinfo->data_precision, return FALSE);
254  INPUT_2BYTES(cinfo, cinfo->image_height, return FALSE);
255  INPUT_2BYTES(cinfo, cinfo->image_width, return FALSE);
256  INPUT_BYTE(cinfo, cinfo->num_components, return FALSE);
257
258  length -= 8;
259
260  TRACEMS4(cinfo, 1, JTRC_SOF, cinfo->unread_marker,
261           (int) cinfo->image_width, (int) cinfo->image_height,
262           cinfo->num_components);
263
264  if (cinfo->marker->saw_SOF)
265    ERREXIT(cinfo, JERR_SOF_DUPLICATE);
266
267  /* We don't support files in which the image height is initially specified */
268  /* as 0 and is later redefined by DNL.  As long as we have to check that,  */
269  /* might as well have a general sanity check. */
270  if (cinfo->image_height <= 0 || cinfo->image_width <= 0
271      || cinfo->num_components <= 0)
272    ERREXIT(cinfo, JERR_EMPTY_IMAGE);
273
274  if (length != (cinfo->num_components * 3))
275    ERREXIT(cinfo, JERR_BAD_LENGTH);
276
277  if (cinfo->comp_info == NULL) /* do only once, even if suspend */
278    cinfo->comp_info = (jpeg_component_info *) (*cinfo->mem->alloc_small)
279                        ((j_common_ptr) cinfo, JPOOL_IMAGE,
280                         cinfo->num_components * SIZEOF(jpeg_component_info));
281 
282  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
283       ci++, compptr++) {
284    compptr->component_index = ci;
285    INPUT_BYTE(cinfo, compptr->component_id, return FALSE);
286    INPUT_BYTE(cinfo, c, return FALSE);
287    compptr->h_samp_factor = (c >> 4) & 15;
288    compptr->v_samp_factor = (c     ) & 15;
289    INPUT_BYTE(cinfo, compptr->quant_tbl_no, return FALSE);
290
291    TRACEMS4(cinfo, 1, JTRC_SOF_COMPONENT,
292             compptr->component_id, compptr->h_samp_factor,
293             compptr->v_samp_factor, compptr->quant_tbl_no);
294  }
295
296  cinfo->marker->saw_SOF = TRUE;
297
298  INPUT_SYNC(cinfo);
299  return TRUE;
300}
301
302
303LOCAL(boolean)
304get_sos (j_decompress_ptr cinfo)
305/* Process a SOS marker */
306{
307  INT32 length;
308  int i, ci, n, c, cc;
309  jpeg_component_info * compptr;
310  INPUT_VARS(cinfo);
311
312  if (! cinfo->marker->saw_SOF)
313    ERREXIT(cinfo, JERR_SOS_NO_SOF);
314
315  INPUT_2BYTES(cinfo, length, return FALSE);
316
317  INPUT_BYTE(cinfo, n, return FALSE); /* Number of components */
318
319  TRACEMS1(cinfo, 1, JTRC_SOS, n);
320
321  if (length != (n * 2 + 6) || n > MAX_COMPS_IN_SCAN ||
322      (n == 0 && !cinfo->progressive_mode))
323      /* pseudo SOS marker only allowed in progressive mode */
324    ERREXIT(cinfo, JERR_BAD_LENGTH);
325
326  cinfo->comps_in_scan = n;
327
328  /* Collect the component-spec parameters */
329
330  for (i = 0; i < n; i++) {
331    INPUT_BYTE(cinfo, cc, return FALSE);
332    INPUT_BYTE(cinfo, c, return FALSE);
333   
334    for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
335         ci++, compptr++) {
336      if (cc == compptr->component_id)
337        goto id_found;
338    }
339
340    ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc);
341
342  id_found:
343
344    cinfo->cur_comp_info[i] = compptr;
345    compptr->dc_tbl_no = (c >> 4) & 15;
346    compptr->ac_tbl_no = (c     ) & 15;
347   
348    TRACEMS3(cinfo, 1, JTRC_SOS_COMPONENT, cc,
349             compptr->dc_tbl_no, compptr->ac_tbl_no);
350  }
351
352  /* Collect the additional scan parameters Ss, Se, Ah/Al. */
353  INPUT_BYTE(cinfo, c, return FALSE);
354  cinfo->Ss = c;
355  INPUT_BYTE(cinfo, c, return FALSE);
356  cinfo->Se = c;
357  INPUT_BYTE(cinfo, c, return FALSE);
358  cinfo->Ah = (c >> 4) & 15;
359  cinfo->Al = (c     ) & 15;
360
361  TRACEMS4(cinfo, 1, JTRC_SOS_PARAMS, cinfo->Ss, cinfo->Se,
362           cinfo->Ah, cinfo->Al);
363
364  /* Prepare to scan data & restart markers */
365  cinfo->marker->next_restart_num = 0;
366
367  /* Count another (non-pseudo) SOS marker */
368  if (n) cinfo->input_scan_number++;
369
370  INPUT_SYNC(cinfo);
371  return TRUE;
372}
373
374
375#ifdef D_ARITH_CODING_SUPPORTED
376
377LOCAL(boolean)
378get_dac (j_decompress_ptr cinfo)
379/* Process a DAC marker */
380{
381  INT32 length;
382  int index, val;
383  INPUT_VARS(cinfo);
384
385  INPUT_2BYTES(cinfo, length, return FALSE);
386  length -= 2;
387 
388  while (length > 0) {
389    INPUT_BYTE(cinfo, index, return FALSE);
390    INPUT_BYTE(cinfo, val, return FALSE);
391
392    length -= 2;
393
394    TRACEMS2(cinfo, 1, JTRC_DAC, index, val);
395
396    if (index < 0 || index >= (2*NUM_ARITH_TBLS))
397      ERREXIT1(cinfo, JERR_DAC_INDEX, index);
398
399    if (index >= NUM_ARITH_TBLS) { /* define AC table */
400      cinfo->arith_ac_K[index-NUM_ARITH_TBLS] = (UINT8) val;
401    } else {                    /* define DC table */
402      cinfo->arith_dc_L[index] = (UINT8) (val & 0x0F);
403      cinfo->arith_dc_U[index] = (UINT8) (val >> 4);
404      if (cinfo->arith_dc_L[index] > cinfo->arith_dc_U[index])
405        ERREXIT1(cinfo, JERR_DAC_VALUE, val);
406    }
407  }
408
409  if (length != 0)
410    ERREXIT(cinfo, JERR_BAD_LENGTH);
411
412  INPUT_SYNC(cinfo);
413  return TRUE;
414}
415
416#else /* ! D_ARITH_CODING_SUPPORTED */
417
418#define get_dac(cinfo)  skip_variable(cinfo)
419
420#endif /* D_ARITH_CODING_SUPPORTED */
421
422
423LOCAL(boolean)
424get_dht (j_decompress_ptr cinfo)
425/* Process a DHT marker */
426{
427  INT32 length;
428  UINT8 bits[17];
429  UINT8 huffval[256];
430  int i, index, count;
431  JHUFF_TBL **htblptr;
432  INPUT_VARS(cinfo);
433
434  INPUT_2BYTES(cinfo, length, return FALSE);
435  length -= 2;
436 
437  while (length > 16) {
438    INPUT_BYTE(cinfo, index, return FALSE);
439
440    TRACEMS1(cinfo, 1, JTRC_DHT, index);
441     
442    bits[0] = 0;
443    count = 0;
444    for (i = 1; i <= 16; i++) {
445      INPUT_BYTE(cinfo, bits[i], return FALSE);
446      count += bits[i];
447    }
448
449    length -= 1 + 16;
450
451    TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
452             bits[1], bits[2], bits[3], bits[4],
453             bits[5], bits[6], bits[7], bits[8]);
454    TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
455             bits[9], bits[10], bits[11], bits[12],
456             bits[13], bits[14], bits[15], bits[16]);
457
458    /* Here we just do minimal validation of the counts to avoid walking
459     * off the end of our table space.  jdhuff.c will check more carefully.
460     */
461    if (count > 256 || ((INT32) count) > length)
462      ERREXIT(cinfo, JERR_BAD_HUFF_TABLE);
463
464    for (i = 0; i < count; i++)
465      INPUT_BYTE(cinfo, huffval[i], return FALSE);
466
467    length -= count;
468
469    if (index & 0x10) {         /* AC table definition */
470      index -= 0x10;
471      htblptr = &cinfo->ac_huff_tbl_ptrs[index];
472    } else {                    /* DC table definition */
473      htblptr = &cinfo->dc_huff_tbl_ptrs[index];
474    }
475
476    if (index < 0 || index >= NUM_HUFF_TBLS)
477      ERREXIT1(cinfo, JERR_DHT_INDEX, index);
478
479    if (*htblptr == NULL)
480      *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
481 
482    MEMCOPY((*htblptr)->bits, bits, SIZEOF((*htblptr)->bits));
483    MEMCOPY((*htblptr)->huffval, huffval, SIZEOF((*htblptr)->huffval));
484  }
485
486  if (length != 0)
487    ERREXIT(cinfo, JERR_BAD_LENGTH);
488
489  INPUT_SYNC(cinfo);
490  return TRUE;
491}
492
493
494LOCAL(boolean)
495get_dqt (j_decompress_ptr cinfo)
496/* Process a DQT marker */
497{
498  INT32 length, count, i;
499  int n, prec;
500  unsigned int tmp;
501  JQUANT_TBL *quant_ptr;
502  const int *natural_order;
503  INPUT_VARS(cinfo);
504
505  INPUT_2BYTES(cinfo, length, return FALSE);
506  length -= 2;
507
508  while (length > 0) {
509    length--;
510    INPUT_BYTE(cinfo, n, return FALSE);
511    prec = n >> 4;
512    n &= 0x0F;
513
514    TRACEMS2(cinfo, 1, JTRC_DQT, n, prec);
515
516    if (n >= NUM_QUANT_TBLS)
517      ERREXIT1(cinfo, JERR_DQT_INDEX, n);
518     
519    if (cinfo->quant_tbl_ptrs[n] == NULL)
520      cinfo->quant_tbl_ptrs[n] = jpeg_alloc_quant_table((j_common_ptr) cinfo);
521    quant_ptr = cinfo->quant_tbl_ptrs[n];
522
523    if (prec) {
524      if (length < DCTSIZE2 * 2) {
525        /* Initialize full table for safety. */
526        for (i = 0; i < DCTSIZE2; i++) {
527          quant_ptr->quantval[i] = 1;
528        }
529        count = length >> 1;
530      } else
531        count = DCTSIZE2;
532    } else {
533      if (length < DCTSIZE2) {
534        /* Initialize full table for safety. */
535        for (i = 0; i < DCTSIZE2; i++) {
536          quant_ptr->quantval[i] = 1;
537        }
538        count = length;
539      } else
540        count = DCTSIZE2;
541    }
542
543    switch (count) {
544    case (2*2): natural_order = jpeg_natural_order2; break;
545    case (3*3): natural_order = jpeg_natural_order3; break;
546    case (4*4): natural_order = jpeg_natural_order4; break;
547    case (5*5): natural_order = jpeg_natural_order5; break;
548    case (6*6): natural_order = jpeg_natural_order6; break;
549    case (7*7): natural_order = jpeg_natural_order7; break;
550    default:    natural_order = jpeg_natural_order;  break;
551    }
552
553    for (i = 0; i < count; i++) {
554      if (prec)
555        INPUT_2BYTES(cinfo, tmp, return FALSE);
556      else
557        INPUT_BYTE(cinfo, tmp, return FALSE);
558      /* We convert the zigzag-order table to natural array order. */
559      quant_ptr->quantval[natural_order[i]] = (UINT16) tmp;
560    }
561
562    if (cinfo->err->trace_level >= 2) {
563      for (i = 0; i < DCTSIZE2; i += 8) {
564        TRACEMS8(cinfo, 2, JTRC_QUANTVALS,
565                 quant_ptr->quantval[i],   quant_ptr->quantval[i+1],
566                 quant_ptr->quantval[i+2], quant_ptr->quantval[i+3],
567                 quant_ptr->quantval[i+4], quant_ptr->quantval[i+5],
568                 quant_ptr->quantval[i+6], quant_ptr->quantval[i+7]);
569      }
570    }
571
572    length -= count;
573    if (prec) length -= count;
574  }
575
576  if (length != 0)
577    ERREXIT(cinfo, JERR_BAD_LENGTH);
578
579  INPUT_SYNC(cinfo);
580  return TRUE;
581}
582
583
584LOCAL(boolean)
585get_dri (j_decompress_ptr cinfo)
586/* Process a DRI marker */
587{
588  INT32 length;
589  unsigned int tmp;
590  INPUT_VARS(cinfo);
591
592  INPUT_2BYTES(cinfo, length, return FALSE);
593 
594  if (length != 4)
595    ERREXIT(cinfo, JERR_BAD_LENGTH);
596
597  INPUT_2BYTES(cinfo, tmp, return FALSE);
598
599  TRACEMS1(cinfo, 1, JTRC_DRI, tmp);
600
601  cinfo->restart_interval = tmp;
602
603  INPUT_SYNC(cinfo);
604  return TRUE;
605}
606
607
608/*
609 * Routines for processing APPn and COM markers.
610 * These are either saved in memory or discarded, per application request.
611 * APP0 and APP14 are specially checked to see if they are
612 * JFIF and Adobe markers, respectively.
613 */
614
615#define APP0_DATA_LEN   14      /* Length of interesting data in APP0 */
616#define APP14_DATA_LEN  12      /* Length of interesting data in APP14 */
617#define APPN_DATA_LEN   14      /* Must be the largest of the above!! */
618
619
620LOCAL(void)
621examine_app0 (j_decompress_ptr cinfo, JOCTET FAR * data,
622              unsigned int datalen, INT32 remaining)
623/* Examine first few bytes from an APP0.
624 * Take appropriate action if it is a JFIF marker.
625 * datalen is # of bytes at data[], remaining is length of rest of marker data.
626 */
627{
628  INT32 totallen = (INT32) datalen + remaining;
629
630  if (datalen >= APP0_DATA_LEN &&
631      GETJOCTET(data[0]) == 0x4A &&
632      GETJOCTET(data[1]) == 0x46 &&
633      GETJOCTET(data[2]) == 0x49 &&
634      GETJOCTET(data[3]) == 0x46 &&
635      GETJOCTET(data[4]) == 0) {
636    /* Found JFIF APP0 marker: save info */
637    cinfo->saw_JFIF_marker = TRUE;
638    cinfo->JFIF_major_version = GETJOCTET(data[5]);
639    cinfo->JFIF_minor_version = GETJOCTET(data[6]);
640    cinfo->density_unit = GETJOCTET(data[7]);
641    cinfo->X_density = (GETJOCTET(data[8]) << 8) + GETJOCTET(data[9]);
642    cinfo->Y_density = (GETJOCTET(data[10]) << 8) + GETJOCTET(data[11]);
643    /* Check version.
644     * Major version must be 1, anything else signals an incompatible change.
645     * (We used to treat this as an error, but now it's a nonfatal warning,
646     * because some bozo at Hijaak couldn't read the spec.)
647     * Minor version should be 0..2, but process anyway if newer.
648     */
649    if (cinfo->JFIF_major_version != 1)
650      WARNMS2(cinfo, JWRN_JFIF_MAJOR,
651              cinfo->JFIF_major_version, cinfo->JFIF_minor_version);
652    /* Generate trace messages */
653    TRACEMS5(cinfo, 1, JTRC_JFIF,
654             cinfo->JFIF_major_version, cinfo->JFIF_minor_version,
655             cinfo->X_density, cinfo->Y_density, cinfo->density_unit);
656    /* Validate thumbnail dimensions and issue appropriate messages */
657    if (GETJOCTET(data[12]) | GETJOCTET(data[13]))
658      TRACEMS2(cinfo, 1, JTRC_JFIF_THUMBNAIL,
659               GETJOCTET(data[12]), GETJOCTET(data[13]));
660    totallen -= APP0_DATA_LEN;
661    if (totallen !=
662        ((INT32)GETJOCTET(data[12]) * (INT32)GETJOCTET(data[13]) * (INT32) 3))
663      TRACEMS1(cinfo, 1, JTRC_JFIF_BADTHUMBNAILSIZE, (int) totallen);
664  } else if (datalen >= 6 &&
665      GETJOCTET(data[0]) == 0x4A &&
666      GETJOCTET(data[1]) == 0x46 &&
667      GETJOCTET(data[2]) == 0x58 &&
668      GETJOCTET(data[3]) == 0x58 &&
669      GETJOCTET(data[4]) == 0) {
670    /* Found JFIF "JFXX" extension APP0 marker */
671    /* The library doesn't actually do anything with these,
672     * but we try to produce a helpful trace message.
673     */
674    switch (GETJOCTET(data[5])) {
675    case 0x10:
676      TRACEMS1(cinfo, 1, JTRC_THUMB_JPEG, (int) totallen);
677      break;
678    case 0x11:
679      TRACEMS1(cinfo, 1, JTRC_THUMB_PALETTE, (int) totallen);
680      break;
681    case 0x13:
682      TRACEMS1(cinfo, 1, JTRC_THUMB_RGB, (int) totallen);
683      break;
684    default:
685      TRACEMS2(cinfo, 1, JTRC_JFIF_EXTENSION,
686               GETJOCTET(data[5]), (int) totallen);
687      break;
688    }
689  } else {
690    /* Start of APP0 does not match "JFIF" or "JFXX", or too short */
691    TRACEMS1(cinfo, 1, JTRC_APP0, (int) totallen);
692  }
693}
694
695
696LOCAL(void)
697examine_app14 (j_decompress_ptr cinfo, JOCTET FAR * data,
698               unsigned int datalen, INT32 remaining)
699/* Examine first few bytes from an APP14.
700 * Take appropriate action if it is an Adobe marker.
701 * datalen is # of bytes at data[], remaining is length of rest of marker data.
702 */
703{
704  unsigned int version, flags0, flags1, transform;
705
706  if (datalen >= APP14_DATA_LEN &&
707      GETJOCTET(data[0]) == 0x41 &&
708      GETJOCTET(data[1]) == 0x64 &&
709      GETJOCTET(data[2]) == 0x6F &&
710      GETJOCTET(data[3]) == 0x62 &&
711      GETJOCTET(data[4]) == 0x65) {
712    /* Found Adobe APP14 marker */
713    version = (GETJOCTET(data[5]) << 8) + GETJOCTET(data[6]);
714    flags0 = (GETJOCTET(data[7]) << 8) + GETJOCTET(data[8]);
715    flags1 = (GETJOCTET(data[9]) << 8) + GETJOCTET(data[10]);
716    transform = GETJOCTET(data[11]);
717    TRACEMS4(cinfo, 1, JTRC_ADOBE, version, flags0, flags1, transform);
718    cinfo->saw_Adobe_marker = TRUE;
719    cinfo->Adobe_transform = (UINT8) transform;
720  } else {
721    /* Start of APP14 does not match "Adobe", or too short */
722    TRACEMS1(cinfo, 1, JTRC_APP14, (int) (datalen + remaining));
723  }
724}
725
726
727METHODDEF(boolean)
728get_interesting_appn (j_decompress_ptr cinfo)
729/* Process an APP0 or APP14 marker without saving it */
730{
731  INT32 length;
732  JOCTET b[APPN_DATA_LEN];
733  unsigned int i, numtoread;
734  INPUT_VARS(cinfo);
735
736  INPUT_2BYTES(cinfo, length, return FALSE);
737  length -= 2;
738
739  /* get the interesting part of the marker data */
740  if (length >= APPN_DATA_LEN)
741    numtoread = APPN_DATA_LEN;
742  else if (length > 0)
743    numtoread = (unsigned int) length;
744  else
745    numtoread = 0;
746  for (i = 0; i < numtoread; i++)
747    INPUT_BYTE(cinfo, b[i], return FALSE);
748  length -= numtoread;
749
750  /* process it */
751  switch (cinfo->unread_marker) {
752  case M_APP0:
753    examine_app0(cinfo, (JOCTET FAR *) b, numtoread, length);
754    break;
755  case M_APP14:
756    examine_app14(cinfo, (JOCTET FAR *) b, numtoread, length);
757    break;
758  default:
759    /* can't get here unless jpeg_save_markers chooses wrong processor */
760    ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
761    break;
762  }
763
764  /* skip any remaining data -- could be lots */
765  INPUT_SYNC(cinfo);
766  if (length > 0)
767    (*cinfo->src->skip_input_data) (cinfo, (long) length);
768
769  return TRUE;
770}
771
772
773#ifdef SAVE_MARKERS_SUPPORTED
774
775METHODDEF(boolean)
776save_marker (j_decompress_ptr cinfo)
777/* Save an APPn or COM marker into the marker list */
778{
779  my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
780  jpeg_saved_marker_ptr cur_marker = marker->cur_marker;
781  unsigned int bytes_read, data_length;
782  JOCTET FAR * data;
783  INT32 length = 0;
784  INPUT_VARS(cinfo);
785
786  if (cur_marker == NULL) {
787    /* begin reading a marker */
788    INPUT_2BYTES(cinfo, length, return FALSE);
789    length -= 2;
790    if (length >= 0) {          /* watch out for bogus length word */
791      /* figure out how much we want to save */
792      unsigned int limit;
793      if (cinfo->unread_marker == (int) M_COM)
794        limit = marker->length_limit_COM;
795      else
796        limit = marker->length_limit_APPn[cinfo->unread_marker - (int) M_APP0];
797      if ((unsigned int) length < limit)
798        limit = (unsigned int) length;
799      /* allocate and initialize the marker item */
800      cur_marker = (jpeg_saved_marker_ptr)
801        (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
802                                    SIZEOF(struct jpeg_marker_struct) + limit);
803      cur_marker->next = NULL;
804      cur_marker->marker = (UINT8) cinfo->unread_marker;
805      cur_marker->original_length = (unsigned int) length;
806      cur_marker->data_length = limit;
807      /* data area is just beyond the jpeg_marker_struct */
808      data = cur_marker->data = (JOCTET FAR *) (cur_marker + 1);
809      marker->cur_marker = cur_marker;
810      marker->bytes_read = 0;
811      bytes_read = 0;
812      data_length = limit;
813    } else {
814      /* deal with bogus length word */
815      bytes_read = data_length = 0;
816      data = NULL;
817    }
818  } else {
819    /* resume reading a marker */
820    bytes_read = marker->bytes_read;
821    data_length = cur_marker->data_length;
822    data = cur_marker->data + bytes_read;
823  }
824
825  while (bytes_read < data_length) {
826    INPUT_SYNC(cinfo);          /* move the restart point to here */
827    marker->bytes_read = bytes_read;
828    /* If there's not at least one byte in buffer, suspend */
829    MAKE_BYTE_AVAIL(cinfo, return FALSE);
830    /* Copy bytes with reasonable rapidity */
831    while (bytes_read < data_length && bytes_in_buffer > 0) {
832      *data++ = *next_input_byte++;
833      bytes_in_buffer--;
834      bytes_read++;
835    }
836  }
837
838  /* Done reading what we want to read */
839  if (cur_marker != NULL) {     /* will be NULL if bogus length word */
840    /* Add new marker to end of list */
841    if (cinfo->marker_list == NULL) {
842      cinfo->marker_list = cur_marker;
843    } else {
844      jpeg_saved_marker_ptr prev = cinfo->marker_list;
845      while (prev->next != NULL)
846        prev = prev->next;
847      prev->next = cur_marker;
848    }
849    /* Reset pointer & calc remaining data length */
850    data = cur_marker->data;
851    length = cur_marker->original_length - data_length;
852  }
853  /* Reset to initial state for next marker */
854  marker->cur_marker = NULL;
855
856  /* Process the marker if interesting; else just make a generic trace msg */
857  switch (cinfo->unread_marker) {
858  case M_APP0:
859    examine_app0(cinfo, data, data_length, length);
860    break;
861  case M_APP14:
862    examine_app14(cinfo, data, data_length, length);
863    break;
864  default:
865    TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker,
866             (int) (data_length + length));
867    break;
868  }
869
870  /* skip any remaining data -- could be lots */
871  INPUT_SYNC(cinfo);            /* do before skip_input_data */
872  if (length > 0)
873    (*cinfo->src->skip_input_data) (cinfo, (long) length);
874
875  return TRUE;
876}
877
878#endif /* SAVE_MARKERS_SUPPORTED */
879
880
881METHODDEF(boolean)
882skip_variable (j_decompress_ptr cinfo)
883/* Skip over an unknown or uninteresting variable-length marker */
884{
885  INT32 length;
886  INPUT_VARS(cinfo);
887
888  INPUT_2BYTES(cinfo, length, return FALSE);
889  length -= 2;
890 
891  TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, (int) length);
892
893  INPUT_SYNC(cinfo);            /* do before skip_input_data */
894  if (length > 0)
895    (*cinfo->src->skip_input_data) (cinfo, (long) length);
896
897  return TRUE;
898}
899
900
901/*
902 * Find the next JPEG marker, save it in cinfo->unread_marker.
903 * Returns FALSE if had to suspend before reaching a marker;
904 * in that case cinfo->unread_marker is unchanged.
905 *
906 * Note that the result might not be a valid marker code,
907 * but it will never be 0 or FF.
908 */
909
910LOCAL(boolean)
911next_marker (j_decompress_ptr cinfo)
912{
913  int c;
914  INPUT_VARS(cinfo);
915
916  for (;;) {
917    INPUT_BYTE(cinfo, c, return FALSE);
918    /* Skip any non-FF bytes.
919     * This may look a bit inefficient, but it will not occur in a valid file.
920     * We sync after each discarded byte so that a suspending data source
921     * can discard the byte from its buffer.
922     */
923    while (c != 0xFF) {
924      cinfo->marker->discarded_bytes++;
925      INPUT_SYNC(cinfo);
926      INPUT_BYTE(cinfo, c, return FALSE);
927    }
928    /* This loop swallows any duplicate FF bytes.  Extra FFs are legal as
929     * pad bytes, so don't count them in discarded_bytes.  We assume there
930     * will not be so many consecutive FF bytes as to overflow a suspending
931     * data source's input buffer.
932     */
933    do {
934      INPUT_BYTE(cinfo, c, return FALSE);
935    } while (c == 0xFF);
936    if (c != 0)
937      break;                    /* found a valid marker, exit loop */
938    /* Reach here if we found a stuffed-zero data sequence (FF/00).
939     * Discard it and loop back to try again.
940     */
941    cinfo->marker->discarded_bytes += 2;
942    INPUT_SYNC(cinfo);
943  }
944
945  if (cinfo->marker->discarded_bytes != 0) {
946    WARNMS2(cinfo, JWRN_EXTRANEOUS_DATA, cinfo->marker->discarded_bytes, c);
947    cinfo->marker->discarded_bytes = 0;
948  }
949
950  cinfo->unread_marker = c;
951
952  INPUT_SYNC(cinfo);
953  return TRUE;
954}
955
956
957LOCAL(boolean)
958first_marker (j_decompress_ptr cinfo)
959/* Like next_marker, but used to obtain the initial SOI marker. */
960/* For this marker, we do not allow preceding garbage or fill; otherwise,
961 * we might well scan an entire input file before realizing it ain't JPEG.
962 * If an application wants to process non-JFIF files, it must seek to the
963 * SOI before calling the JPEG library.
964 */
965{
966  int c, c2;
967  INPUT_VARS(cinfo);
968
969  INPUT_BYTE(cinfo, c, return FALSE);
970  INPUT_BYTE(cinfo, c2, return FALSE);
971  if (c != 0xFF || c2 != (int) M_SOI)
972    ERREXIT2(cinfo, JERR_NO_SOI, c, c2);
973
974  cinfo->unread_marker = c2;
975
976  INPUT_SYNC(cinfo);
977  return TRUE;
978}
979
980
981/*
982 * Read markers until SOS or EOI.
983 *
984 * Returns same codes as are defined for jpeg_consume_input:
985 * JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
986 *
987 * Note: This function may return a pseudo SOS marker (with zero
988 * component number) for treat by input controller's consume_input.
989 * consume_input itself should filter out (skip) the pseudo marker
990 * after processing for the caller.
991 */
992
993METHODDEF(int)
994read_markers (j_decompress_ptr cinfo)
995{
996  /* Outer loop repeats once for each marker. */
997  for (;;) {
998    /* Collect the marker proper, unless we already did. */
999    /* NB: first_marker() enforces the requirement that SOI appear first. */
1000    if (cinfo->unread_marker == 0) {
1001      if (! cinfo->marker->saw_SOI) {
1002        if (! first_marker(cinfo))
1003          return JPEG_SUSPENDED;
1004      } else {
1005        if (! next_marker(cinfo))
1006          return JPEG_SUSPENDED;
1007      }
1008    }
1009    /* At this point cinfo->unread_marker contains the marker code and the
1010     * input point is just past the marker proper, but before any parameters.
1011     * A suspension will cause us to return with this state still true.
1012     */
1013    switch (cinfo->unread_marker) {
1014    case M_SOI:
1015      if (! get_soi(cinfo))
1016        return JPEG_SUSPENDED;
1017      break;
1018
1019    case M_SOF0:                /* Baseline */
1020      if (! get_sof(cinfo, TRUE, FALSE, FALSE))
1021        return JPEG_SUSPENDED;
1022      break;
1023
1024    case M_SOF1:                /* Extended sequential, Huffman */
1025      if (! get_sof(cinfo, FALSE, FALSE, FALSE))
1026        return JPEG_SUSPENDED;
1027      break;
1028
1029    case M_SOF2:                /* Progressive, Huffman */
1030      if (! get_sof(cinfo, FALSE, TRUE, FALSE))
1031        return JPEG_SUSPENDED;
1032      break;
1033
1034    case M_SOF9:                /* Extended sequential, arithmetic */
1035      if (! get_sof(cinfo, FALSE, FALSE, TRUE))
1036        return JPEG_SUSPENDED;
1037      break;
1038
1039    case M_SOF10:               /* Progressive, arithmetic */
1040      if (! get_sof(cinfo, FALSE, TRUE, TRUE))
1041        return JPEG_SUSPENDED;
1042      break;
1043
1044    /* Currently unsupported SOFn types */
1045    case M_SOF3:                /* Lossless, Huffman */
1046    case M_SOF5:                /* Differential sequential, Huffman */
1047    case M_SOF6:                /* Differential progressive, Huffman */
1048    case M_SOF7:                /* Differential lossless, Huffman */
1049    case M_JPG:                 /* Reserved for JPEG extensions */
1050    case M_SOF11:               /* Lossless, arithmetic */
1051    case M_SOF13:               /* Differential sequential, arithmetic */
1052    case M_SOF14:               /* Differential progressive, arithmetic */
1053    case M_SOF15:               /* Differential lossless, arithmetic */
1054      ERREXIT1(cinfo, JERR_SOF_UNSUPPORTED, cinfo->unread_marker);
1055      break;
1056
1057    case M_SOS:
1058      if (! get_sos(cinfo))
1059        return JPEG_SUSPENDED;
1060      cinfo->unread_marker = 0; /* processed the marker */
1061      return JPEG_REACHED_SOS;
1062   
1063    case M_EOI:
1064      TRACEMS(cinfo, 1, JTRC_EOI);
1065      cinfo->unread_marker = 0; /* processed the marker */
1066      return JPEG_REACHED_EOI;
1067     
1068    case M_DAC:
1069      if (! get_dac(cinfo))
1070        return JPEG_SUSPENDED;
1071      break;
1072     
1073    case M_DHT:
1074      if (! get_dht(cinfo))
1075        return JPEG_SUSPENDED;
1076      break;
1077     
1078    case M_DQT:
1079      if (! get_dqt(cinfo))
1080        return JPEG_SUSPENDED;
1081      break;
1082     
1083    case M_DRI:
1084      if (! get_dri(cinfo))
1085        return JPEG_SUSPENDED;
1086      break;
1087     
1088    case M_APP0:
1089    case M_APP1:
1090    case M_APP2:
1091    case M_APP3:
1092    case M_APP4:
1093    case M_APP5:
1094    case M_APP6:
1095    case M_APP7:
1096    case M_APP8:
1097    case M_APP9:
1098    case M_APP10:
1099    case M_APP11:
1100    case M_APP12:
1101    case M_APP13:
1102    case M_APP14:
1103    case M_APP15:
1104      if (! (*((my_marker_ptr) cinfo->marker)->process_APPn[
1105                cinfo->unread_marker - (int) M_APP0]) (cinfo))
1106        return JPEG_SUSPENDED;
1107      break;
1108     
1109    case M_COM:
1110      if (! (*((my_marker_ptr) cinfo->marker)->process_COM) (cinfo))
1111        return JPEG_SUSPENDED;
1112      break;
1113
1114    case M_RST0:                /* these are all parameterless */
1115    case M_RST1:
1116    case M_RST2:
1117    case M_RST3:
1118    case M_RST4:
1119    case M_RST5:
1120    case M_RST6:
1121    case M_RST7:
1122    case M_TEM:
1123      TRACEMS1(cinfo, 1, JTRC_PARMLESS_MARKER, cinfo->unread_marker);
1124      break;
1125
1126    case M_DNL:                 /* Ignore DNL ... perhaps the wrong thing */
1127      if (! skip_variable(cinfo))
1128        return JPEG_SUSPENDED;
1129      break;
1130
1131    default:                    /* must be DHP, EXP, JPGn, or RESn */
1132      /* For now, we treat the reserved markers as fatal errors since they are
1133       * likely to be used to signal incompatible JPEG Part 3 extensions.
1134       * Once the JPEG 3 version-number marker is well defined, this code
1135       * ought to change!
1136       */
1137      ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
1138      break;
1139    }
1140    /* Successfully processed marker, so reset state variable */
1141    cinfo->unread_marker = 0;
1142  } /* end loop */
1143}
1144
1145
1146/*
1147 * Read a restart marker, which is expected to appear next in the datastream;
1148 * if the marker is not there, take appropriate recovery action.
1149 * Returns FALSE if suspension is required.
1150 *
1151 * This is called by the entropy decoder after it has read an appropriate
1152 * number of MCUs.  cinfo->unread_marker may be nonzero if the entropy decoder
1153 * has already read a marker from the data source.  Under normal conditions
1154 * cinfo->unread_marker will be reset to 0 before returning; if not reset,
1155 * it holds a marker which the decoder will be unable to read past.
1156 */
1157
1158METHODDEF(boolean)
1159read_restart_marker (j_decompress_ptr cinfo)
1160{
1161  /* Obtain a marker unless we already did. */
1162  /* Note that next_marker will complain if it skips any data. */
1163  if (cinfo->unread_marker == 0) {
1164    if (! next_marker(cinfo))
1165      return FALSE;
1166  }
1167
1168  if (cinfo->unread_marker ==
1169      ((int) M_RST0 + cinfo->marker->next_restart_num)) {
1170    /* Normal case --- swallow the marker and let entropy decoder continue */
1171    TRACEMS1(cinfo, 3, JTRC_RST, cinfo->marker->next_restart_num);
1172    cinfo->unread_marker = 0;
1173  } else {
1174    /* Uh-oh, the restart markers have been messed up. */
1175    /* Let the data source manager determine how to resync. */
1176    if (! (*cinfo->src->resync_to_restart) (cinfo,
1177                                            cinfo->marker->next_restart_num))
1178      return FALSE;
1179  }
1180
1181  /* Update next-restart state */
1182  cinfo->marker->next_restart_num = (cinfo->marker->next_restart_num + 1) & 7;
1183
1184  return TRUE;
1185}
1186
1187
1188/*
1189 * This is the default resync_to_restart method for data source managers
1190 * to use if they don't have any better approach.  Some data source managers
1191 * may be able to back up, or may have additional knowledge about the data
1192 * which permits a more intelligent recovery strategy; such managers would
1193 * presumably supply their own resync method.
1194 *
1195 * read_restart_marker calls resync_to_restart if it finds a marker other than
1196 * the restart marker it was expecting.  (This code is *not* used unless
1197 * a nonzero restart interval has been declared.)  cinfo->unread_marker is
1198 * the marker code actually found (might be anything, except 0 or FF).
1199 * The desired restart marker number (0..7) is passed as a parameter.
1200 * This routine is supposed to apply whatever error recovery strategy seems
1201 * appropriate in order to position the input stream to the next data segment.
1202 * Note that cinfo->unread_marker is treated as a marker appearing before
1203 * the current data-source input point; usually it should be reset to zero
1204 * before returning.
1205 * Returns FALSE if suspension is required.
1206 *
1207 * This implementation is substantially constrained by wanting to treat the
1208 * input as a data stream; this means we can't back up.  Therefore, we have
1209 * only the following actions to work with:
1210 *   1. Simply discard the marker and let the entropy decoder resume at next
1211 *      byte of file.
1212 *   2. Read forward until we find another marker, discarding intervening
1213 *      data.  (In theory we could look ahead within the current bufferload,
1214 *      without having to discard data if we don't find the desired marker.
1215 *      This idea is not implemented here, in part because it makes behavior
1216 *      dependent on buffer size and chance buffer-boundary positions.)
1217 *   3. Leave the marker unread (by failing to zero cinfo->unread_marker).
1218 *      This will cause the entropy decoder to process an empty data segment,
1219 *      inserting dummy zeroes, and then we will reprocess the marker.
1220 *
1221 * #2 is appropriate if we think the desired marker lies ahead, while #3 is
1222 * appropriate if the found marker is a future restart marker (indicating
1223 * that we have missed the desired restart marker, probably because it got
1224 * corrupted).
1225 * We apply #2 or #3 if the found marker is a restart marker no more than
1226 * two counts behind or ahead of the expected one.  We also apply #2 if the
1227 * found marker is not a legal JPEG marker code (it's certainly bogus data).
1228 * If the found marker is a restart marker more than 2 counts away, we do #1
1229 * (too much risk that the marker is erroneous; with luck we will be able to
1230 * resync at some future point).
1231 * For any valid non-restart JPEG marker, we apply #3.  This keeps us from
1232 * overrunning the end of a scan.  An implementation limited to single-scan
1233 * files might find it better to apply #2 for markers other than EOI, since
1234 * any other marker would have to be bogus data in that case.
1235 */
1236
1237GLOBAL(boolean)
1238jpeg_resync_to_restart (j_decompress_ptr cinfo, int desired)
1239{
1240  int marker = cinfo->unread_marker;
1241  int action = 1;
1242 
1243  /* Always put up a warning. */
1244  WARNMS2(cinfo, JWRN_MUST_RESYNC, marker, desired);
1245 
1246  /* Outer loop handles repeated decision after scanning forward. */
1247  for (;;) {
1248    if (marker < (int) M_SOF0)
1249      action = 2;               /* invalid marker */
1250    else if (marker < (int) M_RST0 || marker > (int) M_RST7)
1251      action = 3;               /* valid non-restart marker */
1252    else {
1253      if (marker == ((int) M_RST0 + ((desired+1) & 7)) ||
1254          marker == ((int) M_RST0 + ((desired+2) & 7)))
1255        action = 3;             /* one of the next two expected restarts */
1256      else if (marker == ((int) M_RST0 + ((desired-1) & 7)) ||
1257               marker == ((int) M_RST0 + ((desired-2) & 7)))
1258        action = 2;             /* a prior restart, so advance */
1259      else
1260        action = 1;             /* desired restart or too far away */
1261    }
1262    TRACEMS2(cinfo, 4, JTRC_RECOVERY_ACTION, marker, action);
1263    switch (action) {
1264    case 1:
1265      /* Discard marker and let entropy decoder resume processing. */
1266      cinfo->unread_marker = 0;
1267      return TRUE;
1268    case 2:
1269      /* Scan to the next marker, and repeat the decision loop. */
1270      if (! next_marker(cinfo))
1271        return FALSE;
1272      marker = cinfo->unread_marker;
1273      break;
1274    case 3:
1275      /* Return without advancing past this marker. */
1276      /* Entropy decoder will be forced to process an empty segment. */
1277      return TRUE;
1278    }
1279  } /* end loop */
1280}
1281
1282
1283/*
1284 * Reset marker processing state to begin a fresh datastream.
1285 */
1286
1287METHODDEF(void)
1288reset_marker_reader (j_decompress_ptr cinfo)
1289{
1290  my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1291
1292  cinfo->comp_info = NULL;              /* until allocated by get_sof */
1293  cinfo->input_scan_number = 0;         /* no SOS seen yet */
1294  cinfo->unread_marker = 0;             /* no pending marker */
1295  marker->pub.saw_SOI = FALSE;          /* set internal state too */
1296  marker->pub.saw_SOF = FALSE;
1297  marker->pub.discarded_bytes = 0;
1298  marker->cur_marker = NULL;
1299}
1300
1301
1302/*
1303 * Initialize the marker reader module.
1304 * This is called only once, when the decompression object is created.
1305 */
1306
1307GLOBAL(void)
1308jinit_marker_reader (j_decompress_ptr cinfo)
1309{
1310  my_marker_ptr marker;
1311  int i;
1312
1313  /* Create subobject in permanent pool */
1314  marker = (my_marker_ptr)
1315    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
1316                                SIZEOF(my_marker_reader));
1317  cinfo->marker = (struct jpeg_marker_reader *) marker;
1318  /* Initialize public method pointers */
1319  marker->pub.reset_marker_reader = reset_marker_reader;
1320  marker->pub.read_markers = read_markers;
1321  marker->pub.read_restart_marker = read_restart_marker;
1322  /* Initialize COM/APPn processing.
1323   * By default, we examine and then discard APP0 and APP14,
1324   * but simply discard COM and all other APPn.
1325   */
1326  marker->process_COM = skip_variable;
1327  marker->length_limit_COM = 0;
1328  for (i = 0; i < 16; i++) {
1329    marker->process_APPn[i] = skip_variable;
1330    marker->length_limit_APPn[i] = 0;
1331  }
1332  marker->process_APPn[0] = get_interesting_appn;
1333  marker->process_APPn[14] = get_interesting_appn;
1334  /* Reset marker processing state */
1335  reset_marker_reader(cinfo);
1336}
1337
1338
1339/*
1340 * Control saving of COM and APPn markers into marker_list.
1341 */
1342
1343#ifdef SAVE_MARKERS_SUPPORTED
1344
1345GLOBAL(void)
1346jpeg_save_markers (j_decompress_ptr cinfo, int marker_code,
1347                   unsigned int length_limit)
1348{
1349  my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1350  long maxlength;
1351  jpeg_marker_parser_method processor;
1352
1353  /* Length limit mustn't be larger than what we can allocate
1354   * (should only be a concern in a 16-bit environment).
1355   */
1356  maxlength = cinfo->mem->max_alloc_chunk - SIZEOF(struct jpeg_marker_struct);
1357  if (((long) length_limit) > maxlength)
1358    length_limit = (unsigned int) maxlength;
1359
1360  /* Choose processor routine to use.
1361   * APP0/APP14 have special requirements.
1362   */
1363  if (length_limit) {
1364    processor = save_marker;
1365    /* If saving APP0/APP14, save at least enough for our internal use. */
1366    if (marker_code == (int) M_APP0 && length_limit < APP0_DATA_LEN)
1367      length_limit = APP0_DATA_LEN;
1368    else if (marker_code == (int) M_APP14 && length_limit < APP14_DATA_LEN)
1369      length_limit = APP14_DATA_LEN;
1370  } else {
1371    processor = skip_variable;
1372    /* If discarding APP0/APP14, use our regular on-the-fly processor. */
1373    if (marker_code == (int) M_APP0 || marker_code == (int) M_APP14)
1374      processor = get_interesting_appn;
1375  }
1376
1377  if (marker_code == (int) M_COM) {
1378    marker->process_COM = processor;
1379    marker->length_limit_COM = length_limit;
1380  } else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15) {
1381    marker->process_APPn[marker_code - (int) M_APP0] = processor;
1382    marker->length_limit_APPn[marker_code - (int) M_APP0] = length_limit;
1383  } else
1384    ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
1385}
1386
1387#endif /* SAVE_MARKERS_SUPPORTED */
1388
1389
1390/*
1391 * Install a special processing method for COM or APPn markers.
1392 */
1393
1394GLOBAL(void)
1395jpeg_set_marker_processor (j_decompress_ptr cinfo, int marker_code,
1396                           jpeg_marker_parser_method routine)
1397{
1398  my_marker_ptr marker = (my_marker_ptr) cinfo->marker;
1399
1400  if (marker_code == (int) M_COM)
1401    marker->process_COM = routine;
1402  else if (marker_code >= (int) M_APP0 && marker_code <= (int) M_APP15)
1403    marker->process_APPn[marker_code - (int) M_APP0] = routine;
1404  else
1405    ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, marker_code);
1406}
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