source: golgotha/src/i4/loaders/jpg/jdmarker.cc @ 80

Last change on this file since 80 was 80, checked in by Sam Hocevar, 11 years ago
  • Adding the Golgotha source code. Not sure what's going to be interesting in there, but since it's all public domain, there's certainly stuff to pick up.
File size: 30.5 KB
Line 
1/********************************************************************** <BR>
2  This file is part of Crack dot Com's free source code release of
3  Golgotha. <a href="http://www.crack.com/golgotha_release"> <BR> for
4  information about compiling & licensing issues visit this URL</a>
5  <PRE> If that doesn't help, contact Jonathan Clark at
6  golgotha_source@usa.net (Subject should have "GOLG" in it)
7***********************************************************************/
8
9/*
10 * jdmarker.c
11 *
12 * Copyright (C) 1991-1996, Thomas G. Lane.
13 * This file is part of the Independent JPEG Group's software.
14 * For conditions of distribution and use, see the accompanying README file.
15 *
16 * This file contains routines to decode JPEG datastream markers.
17 * Most of the complexity arises from our desire to support input
18 * suspension: if not all of the data for a marker is available,
19 * we must exit back to the application.  On resumption, we reprocess
20 * the marker.
21 */
22
23#define JPEG_INTERNALS
24#include "loaders/jpg/jinclude.h"
25#include "loaders/jpg/jpeglib.h"
26
27
28typedef enum {                  /* JPEG marker codes */
29  M_SOF0  = 0xc0,
30  M_SOF1  = 0xc1,
31  M_SOF2  = 0xc2,
32  M_SOF3  = 0xc3,
33 
34  M_SOF5  = 0xc5,
35  M_SOF6  = 0xc6,
36  M_SOF7  = 0xc7,
37 
38  M_JPG   = 0xc8,
39  M_SOF9  = 0xc9,
40  M_SOF10 = 0xca,
41  M_SOF11 = 0xcb,
42 
43  M_SOF13 = 0xcd,
44  M_SOF14 = 0xce,
45  M_SOF15 = 0xcf,
46 
47  M_DHT   = 0xc4,
48 
49  M_DAC   = 0xcc,
50 
51  M_RST0  = 0xd0,
52  M_RST1  = 0xd1,
53  M_RST2  = 0xd2,
54  M_RST3  = 0xd3,
55  M_RST4  = 0xd4,
56  M_RST5  = 0xd5,
57  M_RST6  = 0xd6,
58  M_RST7  = 0xd7,
59 
60  M_SOI   = 0xd8,
61  M_EOI   = 0xd9,
62  M_SOS   = 0xda,
63  M_DQT   = 0xdb,
64  M_DNL   = 0xdc,
65  M_DRI   = 0xdd,
66  M_DHP   = 0xde,
67  M_EXP   = 0xdf,
68 
69  M_APP0  = 0xe0,
70  M_APP1  = 0xe1,
71  M_APP2  = 0xe2,
72  M_APP3  = 0xe3,
73  M_APP4  = 0xe4,
74  M_APP5  = 0xe5,
75  M_APP6  = 0xe6,
76  M_APP7  = 0xe7,
77  M_APP8  = 0xe8,
78  M_APP9  = 0xe9,
79  M_APP10 = 0xea,
80  M_APP11 = 0xeb,
81  M_APP12 = 0xec,
82  M_APP13 = 0xed,
83  M_APP14 = 0xee,
84  M_APP15 = 0xef,
85 
86  M_JPG0  = 0xf0,
87  M_JPG13 = 0xfd,
88  M_COM   = 0xfe,
89 
90  M_TEM   = 0x01,
91 
92  M_ERROR = 0x100
93} JPEG_MARKER;
94
95
96/*
97 * Macros for fetching data from the data source module.
98 *
99 * At all times, cinfo->src->next_input_byte and ->bytes_in_buffer reflect
100 * the current restart point; we update them only when we have reached a
101 * suitable place to restart if a suspension occurs.
102 */
103
104/* Declare and initialize local copies of input pointer/count */
105#define INPUT_VARS(cinfo)  \
106        struct jpeg_source_mgr * datasrc = (cinfo)->src;  \
107        const JOCTET * next_input_byte = datasrc->next_input_byte;  \
108        size_t bytes_in_buffer = datasrc->bytes_in_buffer
109
110/* Unload the local copies --- do this only at a restart boundary */
111#define INPUT_SYNC(cinfo)  \
112        ( datasrc->next_input_byte = next_input_byte,  \
113          datasrc->bytes_in_buffer = bytes_in_buffer )
114
115/* Reload the local copies --- seldom used except in MAKE_BYTE_AVAIL */
116#define INPUT_RELOAD(cinfo)  \
117        ( next_input_byte = datasrc->next_input_byte,  \
118          bytes_in_buffer = datasrc->bytes_in_buffer )
119
120/* Internal macro for INPUT_BYTE and INPUT_2BYTES: make a byte available.
121 * Note we do *not* do INPUT_SYNC before calling fill_input_buffer,
122 * but we must reload the local copies after a successful fill.
123 */
124#define MAKE_BYTE_AVAIL(cinfo,action)  \
125        if (bytes_in_buffer == 0) {  \
126          if (! (*datasrc->fill_input_buffer) (cinfo))  \
127            { action; }  \
128          INPUT_RELOAD(cinfo);  \
129        }  \
130        bytes_in_buffer--
131
132/* Read a byte into variable V.
133 * If must suspend, take the specified action (typically "return FALSE").
134 */
135#define INPUT_BYTE(cinfo,V,action)  \
136        MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \
137                  V = GETJOCTET(*next_input_byte++); )
138
139/* As above, but read two bytes interpreted as an unsigned 16-bit integer.
140 * V should be declared unsigned int or perhaps INT32.
141 */
142#define INPUT_2BYTES(cinfo,V,action)  \
143        MAKESTMT( MAKE_BYTE_AVAIL(cinfo,action); \
144                  V = ((unsigned int) GETJOCTET(*next_input_byte++)) << 8; \
145                  MAKE_BYTE_AVAIL(cinfo,action); \
146                  V += GETJOCTET(*next_input_byte++); )
147
148
149/*
150 * Routines to process JPEG markers.
151 *
152 * Entry condition: JPEG marker itself has been read and its code saved
153 *   in cinfo->unread_marker; input restart point is just after the marker.
154 *
155 * Exit: if return TRUE, have read and processed any parameters, and have
156 *   updated the restart point to point after the parameters.
157 *   If return FALSE, was forced to suspend before reaching end of
158 *   marker parameters; restart point has not been moved.  Same routine
159 *   will be called again after application supplies more input data.
160 *
161 * This approach to suspension assumes that all of a marker's parameters can
162 * fit into a single input bufferload.  This should hold for "normal"
163 * markers.  Some COM/APPn markers might have large parameter segments,
164 * but we use skip_input_data to get past those, and thereby put the problem
165 * on the source manager's shoulders.
166 *
167 * Note that we don't bother to avoid duplicate trace messages if a
168 * suspension occurs within marker parameters.  Other side effects
169 * require more care.
170 */
171
172
173LOCAL(boolean)
174get_soi (j_decompress_ptr cinfo)
175/* Process an SOI marker */
176{
177  int i;
178 
179  TRACEMS(cinfo, 1, JTRC_SOI);
180
181  if (cinfo->marker->saw_SOI)
182    ERREXIT(cinfo, JERR_SOI_DUPLICATE);
183
184  /* Reset all parameters that are defined to be reset by SOI */
185
186  for (i = 0; i < NUM_ARITH_TBLS; i++) {
187    cinfo->arith_dc_L[i] = 0;
188    cinfo->arith_dc_U[i] = 1;
189    cinfo->arith_ac_K[i] = 5;
190  }
191  cinfo->restart_interval = 0;
192
193  /* Set initial assumptions for colorspace etc */
194
195  cinfo->jpeg_color_space = JCS_UNKNOWN;
196  cinfo->CCIR601_sampling = FALSE; /* Assume non-CCIR sampling??? */
197
198  cinfo->saw_JFIF_marker = FALSE;
199  cinfo->density_unit = 0;      /* set default JFIF APP0 values */
200  cinfo->X_density = 1;
201  cinfo->Y_density = 1;
202  cinfo->saw_Adobe_marker = FALSE;
203  cinfo->Adobe_transform = 0;
204
205  cinfo->marker->saw_SOI = TRUE;
206
207  return TRUE;
208}
209
210
211LOCAL(boolean)
212get_sof (j_decompress_ptr cinfo, boolean is_prog, boolean is_arith)
213/* Process a SOFn marker */
214{
215  INT32 length;
216  int c, ci;
217  jpeg_component_info * compptr;
218  INPUT_VARS(cinfo);
219
220  cinfo->progressive_mode = is_prog;
221  cinfo->arith_code = is_arith;
222
223  INPUT_2BYTES(cinfo, length, return FALSE);
224
225  INPUT_BYTE(cinfo, cinfo->data_precision, return FALSE);
226  INPUT_2BYTES(cinfo, cinfo->image_height, return FALSE);
227  INPUT_2BYTES(cinfo, cinfo->image_width, return FALSE);
228  INPUT_BYTE(cinfo, cinfo->num_components, return FALSE);
229
230  length -= 8;
231
232  TRACEMS4(cinfo, 1, JTRC_SOF, cinfo->unread_marker,
233           (int) cinfo->image_width, (int) cinfo->image_height,
234           cinfo->num_components);
235
236  if (cinfo->marker->saw_SOF)
237    ERREXIT(cinfo, JERR_SOF_DUPLICATE);
238
239  /* We don't support files in which the image height is initially specified */
240  /* as 0 and is later redefined by DNL.  As long as we have to check that,  */
241  /* might as well have a general sanity check. */
242  if (cinfo->image_height <= 0 || cinfo->image_width <= 0
243      || cinfo->num_components <= 0)
244    ERREXIT(cinfo, JERR_EMPTY_IMAGE);
245
246  if (length != (cinfo->num_components * 3))
247    ERREXIT(cinfo, JERR_BAD_LENGTH);
248
249  if (cinfo->comp_info == NULL) /* do only once, even if suspend */
250    cinfo->comp_info = (jpeg_component_info *) (*cinfo->mem->alloc_small)
251                        ((j_common_ptr) cinfo, JPOOL_IMAGE,
252                         cinfo->num_components * SIZEOF(jpeg_component_info));
253 
254  for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
255       ci++, compptr++) {
256    compptr->component_index = ci;
257    INPUT_BYTE(cinfo, compptr->component_id, return FALSE);
258    INPUT_BYTE(cinfo, c, return FALSE);
259    compptr->h_samp_factor = (c >> 4) & 15;
260    compptr->v_samp_factor = (c     ) & 15;
261    INPUT_BYTE(cinfo, compptr->quant_tbl_no, return FALSE);
262
263    TRACEMS4(cinfo, 1, JTRC_SOF_COMPONENT,
264             compptr->component_id, compptr->h_samp_factor,
265             compptr->v_samp_factor, compptr->quant_tbl_no);
266  }
267
268  cinfo->marker->saw_SOF = TRUE;
269
270  INPUT_SYNC(cinfo);
271  return TRUE;
272}
273
274
275LOCAL(boolean)
276get_sos (j_decompress_ptr cinfo)
277/* Process a SOS marker */
278{
279  INT32 length;
280  int i, ci, n, c, cc;
281  jpeg_component_info * compptr;
282  INPUT_VARS(cinfo);
283
284  if (! cinfo->marker->saw_SOF)
285    ERREXIT(cinfo, JERR_SOS_NO_SOF);
286
287  INPUT_2BYTES(cinfo, length, return FALSE);
288
289  INPUT_BYTE(cinfo, n, return FALSE); /* Number of components */
290
291  if (length != (n * 2 + 6) || n < 1 || n > MAX_COMPS_IN_SCAN)
292    ERREXIT(cinfo, JERR_BAD_LENGTH);
293
294  TRACEMS1(cinfo, 1, JTRC_SOS, n);
295
296  cinfo->comps_in_scan = n;
297
298  /* Collect the component-spec parameters */
299
300  for (i = 0; i < n; i++) {
301    INPUT_BYTE(cinfo, cc, return FALSE);
302    INPUT_BYTE(cinfo, c, return FALSE);
303   
304    for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
305         ci++, compptr++) {
306      if (cc == compptr->component_id)
307        goto id_found;
308    }
309
310    ERREXIT1(cinfo, JERR_BAD_COMPONENT_ID, cc);
311
312  id_found:
313
314    cinfo->cur_comp_info[i] = compptr;
315    compptr->dc_tbl_no = (c >> 4) & 15;
316    compptr->ac_tbl_no = (c     ) & 15;
317   
318    TRACEMS3(cinfo, 1, JTRC_SOS_COMPONENT, cc,
319             compptr->dc_tbl_no, compptr->ac_tbl_no);
320  }
321
322  /* Collect the additional scan parameters Ss, Se, Ah/Al. */
323  INPUT_BYTE(cinfo, c, return FALSE);
324  cinfo->Ss = c;
325  INPUT_BYTE(cinfo, c, return FALSE);
326  cinfo->Se = c;
327  INPUT_BYTE(cinfo, c, return FALSE);
328  cinfo->Ah = (c >> 4) & 15;
329  cinfo->Al = (c     ) & 15;
330
331  TRACEMS4(cinfo, 1, JTRC_SOS_PARAMS, cinfo->Ss, cinfo->Se,
332           cinfo->Ah, cinfo->Al);
333
334  /* Prepare to scan data & restart markers */
335  cinfo->marker->next_restart_num = 0;
336
337  /* Count another SOS marker */
338  cinfo->input_scan_number++;
339
340  INPUT_SYNC(cinfo);
341  return TRUE;
342}
343
344
345METHODDEF(boolean)
346get_app0 (j_decompress_ptr cinfo)
347/* Process an APP0 marker */
348{
349#define JFIF_LEN 14
350  INT32 length;
351  UINT8 b[JFIF_LEN];
352  int buffp;
353  INPUT_VARS(cinfo);
354
355  INPUT_2BYTES(cinfo, length, return FALSE);
356  length -= 2;
357
358  /* See if a JFIF APP0 marker is present */
359
360  if (length >= JFIF_LEN) {
361    for (buffp = 0; buffp < JFIF_LEN; buffp++)
362      INPUT_BYTE(cinfo, b[buffp], return FALSE);
363    length -= JFIF_LEN;
364
365    if (b[0]==0x4A && b[1]==0x46 && b[2]==0x49 && b[3]==0x46 && b[4]==0) {
366      /* Found JFIF APP0 marker: check version */
367      /* Major version must be 1, anything else signals an incompatible change.
368       * We used to treat this as an error, but now it's a nonfatal warning,
369       * because some bozo at Hijaak couldn't read the spec.
370       * Minor version should be 0..2, but process anyway if newer.
371       */
372      if (b[5] != 1)
373        WARNMS2(cinfo, JWRN_JFIF_MAJOR, b[5], b[6]);
374      else if (b[6] > 2)
375        TRACEMS2(cinfo, 1, JTRC_JFIF_MINOR, b[5], b[6]);
376      /* Save info */
377      cinfo->saw_JFIF_marker = TRUE;
378      cinfo->density_unit = b[7];
379      cinfo->X_density = (b[8] << 8) + b[9];
380      cinfo->Y_density = (b[10] << 8) + b[11];
381      TRACEMS3(cinfo, 1, JTRC_JFIF,
382               cinfo->X_density, cinfo->Y_density, cinfo->density_unit);
383      if (b[12] | b[13])
384        TRACEMS2(cinfo, 1, JTRC_JFIF_THUMBNAIL, b[12], b[13]);
385      if (length != ((INT32) b[12] * (INT32) b[13] * (INT32) 3))
386        TRACEMS1(cinfo, 1, JTRC_JFIF_BADTHUMBNAILSIZE, (int) length);
387    } else {
388      /* Start of APP0 does not match "JFIF" */
389      TRACEMS1(cinfo, 1, JTRC_APP0, (int) length + JFIF_LEN);
390    }
391  } else {
392    /* Too short to be JFIF marker */
393    TRACEMS1(cinfo, 1, JTRC_APP0, (int) length);
394  }
395
396  INPUT_SYNC(cinfo);
397  if (length > 0)               /* skip any remaining data -- could be lots */
398    (*cinfo->src->skip_input_data) (cinfo, (long) length);
399
400  return TRUE;
401}
402
403
404METHODDEF(boolean)
405get_app14 (j_decompress_ptr cinfo)
406/* Process an APP14 marker */
407{
408#define ADOBE_LEN 12
409  INT32 length;
410  UINT8 b[ADOBE_LEN];
411  int buffp;
412  unsigned int version, flags0, flags1, transform;
413  INPUT_VARS(cinfo);
414
415  INPUT_2BYTES(cinfo, length, return FALSE);
416  length -= 2;
417
418  /* See if an Adobe APP14 marker is present */
419
420  if (length >= ADOBE_LEN) {
421    for (buffp = 0; buffp < ADOBE_LEN; buffp++)
422      INPUT_BYTE(cinfo, b[buffp], return FALSE);
423    length -= ADOBE_LEN;
424
425    if (b[0]==0x41 && b[1]==0x64 && b[2]==0x6F && b[3]==0x62 && b[4]==0x65) {
426      /* Found Adobe APP14 marker */
427      version = (b[5] << 8) + b[6];
428      flags0 = (b[7] << 8) + b[8];
429      flags1 = (b[9] << 8) + b[10];
430      transform = b[11];
431      TRACEMS4(cinfo, 1, JTRC_ADOBE, version, flags0, flags1, transform);
432      cinfo->saw_Adobe_marker = TRUE;
433      cinfo->Adobe_transform = (UINT8) transform;
434    } else {
435      /* Start of APP14 does not match "Adobe" */
436      TRACEMS1(cinfo, 1, JTRC_APP14, (int) length + ADOBE_LEN);
437    }
438  } else {
439    /* Too short to be Adobe marker */
440    TRACEMS1(cinfo, 1, JTRC_APP14, (int) length);
441  }
442
443  INPUT_SYNC(cinfo);
444  if (length > 0)               /* skip any remaining data -- could be lots */
445    (*cinfo->src->skip_input_data) (cinfo, (long) length);
446
447  return TRUE;
448}
449
450
451LOCAL(boolean)
452get_dac (j_decompress_ptr cinfo)
453/* Process a DAC marker */
454{
455  INT32 length;
456  int index, val;
457  INPUT_VARS(cinfo);
458
459  INPUT_2BYTES(cinfo, length, return FALSE);
460  length -= 2;
461 
462  while (length > 0) {
463    INPUT_BYTE(cinfo, index, return FALSE);
464    INPUT_BYTE(cinfo, val, return FALSE);
465
466    length -= 2;
467
468    TRACEMS2(cinfo, 1, JTRC_DAC, index, val);
469
470    if (index < 0 || index >= (2*NUM_ARITH_TBLS))
471      ERREXIT1(cinfo, JERR_DAC_INDEX, index);
472
473    if (index >= NUM_ARITH_TBLS) { /* define AC table */
474      cinfo->arith_ac_K[index-NUM_ARITH_TBLS] = (UINT8) val;
475    } else {                    /* define DC table */
476      cinfo->arith_dc_L[index] = (UINT8) (val & 0x0F);
477      cinfo->arith_dc_U[index] = (UINT8) (val >> 4);
478      if (cinfo->arith_dc_L[index] > cinfo->arith_dc_U[index])
479        ERREXIT1(cinfo, JERR_DAC_VALUE, val);
480    }
481  }
482
483  INPUT_SYNC(cinfo);
484  return TRUE;
485}
486
487
488LOCAL(boolean)
489get_dht (j_decompress_ptr cinfo)
490/* Process a DHT marker */
491{
492  INT32 length;
493  UINT8 bits[17];
494  UINT8 huffval[256];
495  int i, index, count;
496  JHUFF_TBL **htblptr;
497  INPUT_VARS(cinfo);
498
499  INPUT_2BYTES(cinfo, length, return FALSE);
500  length -= 2;
501 
502  while (length > 0) {
503    INPUT_BYTE(cinfo, index, return FALSE);
504
505    TRACEMS1(cinfo, 1, JTRC_DHT, index);
506     
507    bits[0] = 0;
508    count = 0;
509    for (i = 1; i <= 16; i++) {
510      INPUT_BYTE(cinfo, bits[i], return FALSE);
511      count += bits[i];
512    }
513
514    length -= 1 + 16;
515
516    TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
517             bits[1], bits[2], bits[3], bits[4],
518             bits[5], bits[6], bits[7], bits[8]);
519    TRACEMS8(cinfo, 2, JTRC_HUFFBITS,
520             bits[9], bits[10], bits[11], bits[12],
521             bits[13], bits[14], bits[15], bits[16]);
522
523    if (count > 256 || ((INT32) count) > length)
524      ERREXIT(cinfo, JERR_DHT_COUNTS);
525
526    for (i = 0; i < count; i++)
527      INPUT_BYTE(cinfo, huffval[i], return FALSE);
528
529    length -= count;
530
531    if (index & 0x10) {         /* AC table definition */
532      index -= 0x10;
533      htblptr = &cinfo->ac_huff_tbl_ptrs[index];
534    } else {                    /* DC table definition */
535      htblptr = &cinfo->dc_huff_tbl_ptrs[index];
536    }
537
538    if (index < 0 || index >= NUM_HUFF_TBLS)
539      ERREXIT1(cinfo, JERR_DHT_INDEX, index);
540
541    if (*htblptr == NULL)
542      *htblptr = jpeg_alloc_huff_table((j_common_ptr) cinfo);
543 
544    MEMCOPY((*htblptr)->bits, bits, SIZEOF((*htblptr)->bits));
545    MEMCOPY((*htblptr)->huffval, huffval, SIZEOF((*htblptr)->huffval));
546  }
547
548  INPUT_SYNC(cinfo);
549  return TRUE;
550}
551
552
553LOCAL(boolean)
554get_dqt (j_decompress_ptr cinfo)
555/* Process a DQT marker */
556{
557  INT32 length;
558  int n, i, prec;
559  unsigned int tmp;
560  JQUANT_TBL *quant_ptr;
561  INPUT_VARS(cinfo);
562
563  INPUT_2BYTES(cinfo, length, return FALSE);
564  length -= 2;
565
566  while (length > 0) {
567    INPUT_BYTE(cinfo, n, return FALSE);
568    prec = n >> 4;
569    n &= 0x0F;
570
571    TRACEMS2(cinfo, 1, JTRC_DQT, n, prec);
572
573    if (n >= NUM_QUANT_TBLS)
574      ERREXIT1(cinfo, JERR_DQT_INDEX, n);
575     
576    if (cinfo->quant_tbl_ptrs[n] == NULL)
577      cinfo->quant_tbl_ptrs[n] = jpeg_alloc_quant_table((j_common_ptr) cinfo);
578    quant_ptr = cinfo->quant_tbl_ptrs[n];
579
580    for (i = 0; i < DCTSIZE2; i++) {
581      if (prec)
582        INPUT_2BYTES(cinfo, tmp, return FALSE);
583      else
584        INPUT_BYTE(cinfo, tmp, return FALSE);
585      /* We convert the zigzag-order table to natural array order. */
586      quant_ptr->quantval[jpeg_natural_order[i]] = (UINT16) tmp;
587    }
588
589    if (cinfo->err->trace_level >= 2) {
590      for (i = 0; i < DCTSIZE2; i += 8) {
591        TRACEMS8(cinfo, 2, JTRC_QUANTVALS,
592                 quant_ptr->quantval[i],   quant_ptr->quantval[i+1],
593                 quant_ptr->quantval[i+2], quant_ptr->quantval[i+3],
594                 quant_ptr->quantval[i+4], quant_ptr->quantval[i+5],
595                 quant_ptr->quantval[i+6], quant_ptr->quantval[i+7]);
596      }
597    }
598
599    length -= DCTSIZE2+1;
600    if (prec) length -= DCTSIZE2;
601  }
602
603  INPUT_SYNC(cinfo);
604  return TRUE;
605}
606
607
608LOCAL(boolean)
609get_dri (j_decompress_ptr cinfo)
610/* Process a DRI marker */
611{
612  INT32 length;
613  unsigned int tmp;
614  INPUT_VARS(cinfo);
615
616  INPUT_2BYTES(cinfo, length, return FALSE);
617 
618  if (length != 4)
619    ERREXIT(cinfo, JERR_BAD_LENGTH);
620
621  INPUT_2BYTES(cinfo, tmp, return FALSE);
622
623  TRACEMS1(cinfo, 1, JTRC_DRI, tmp);
624
625  cinfo->restart_interval = tmp;
626
627  INPUT_SYNC(cinfo);
628  return TRUE;
629}
630
631
632METHODDEF(boolean)
633skip_variable (j_decompress_ptr cinfo)
634/* Skip over an unknown or uninteresting variable-length marker */
635{
636  INT32 length;
637  INPUT_VARS(cinfo);
638
639  INPUT_2BYTES(cinfo, length, return FALSE);
640 
641  TRACEMS2(cinfo, 1, JTRC_MISC_MARKER, cinfo->unread_marker, (int) length);
642
643  INPUT_SYNC(cinfo);            /* do before skip_input_data */
644  (*cinfo->src->skip_input_data) (cinfo, (long) length - 2L);
645
646  return TRUE;
647}
648
649
650/*
651 * Find the next JPEG marker, save it in cinfo->unread_marker.
652 * Returns FALSE if had to suspend before reaching a marker;
653 * in that case cinfo->unread_marker is unchanged.
654 *
655 * Note that the result might not be a valid marker code,
656 * but it will never be 0 or FF.
657 */
658
659LOCAL(boolean)
660next_marker (j_decompress_ptr cinfo)
661{
662  int c;
663  INPUT_VARS(cinfo);
664
665  for (;;) {
666    INPUT_BYTE(cinfo, c, return FALSE);
667    /* Skip any non-FF bytes.
668     * This may look a bit inefficient, but it will not occur in a valid file.
669     * We sync after each discarded byte so that a suspending data source
670     * can discard the byte from its buffer.
671     */
672    while (c != 0xFF) {
673      cinfo->marker->discarded_bytes++;
674      INPUT_SYNC(cinfo);
675      INPUT_BYTE(cinfo, c, return FALSE);
676    }
677    /* This loop swallows any duplicate FF bytes.  Extra FFs are legal as
678     * pad bytes, so don't count them in discarded_bytes.  We assume there
679     * will not be so many consecutive FF bytes as to overflow a suspending
680     * data source's input buffer.
681     */
682    do {
683      INPUT_BYTE(cinfo, c, return FALSE);
684    } while (c == 0xFF);
685    if (c != 0)
686      break;                    /* found a valid marker, exit loop */
687    /* Reach here if we found a stuffed-zero data sequence (FF/00).
688     * Discard it and loop back to try again.
689     */
690    cinfo->marker->discarded_bytes += 2;
691    INPUT_SYNC(cinfo);
692  }
693
694  if (cinfo->marker->discarded_bytes != 0) {
695    WARNMS2(cinfo, JWRN_EXTRANEOUS_DATA, cinfo->marker->discarded_bytes, c);
696    cinfo->marker->discarded_bytes = 0;
697  }
698
699  cinfo->unread_marker = c;
700
701  INPUT_SYNC(cinfo);
702  return TRUE;
703}
704
705
706LOCAL(boolean)
707first_marker (j_decompress_ptr cinfo)
708/* Like next_marker, but used to obtain the initial SOI marker. */
709/* For this marker, we do not allow preceding garbage or fill; otherwise,
710 * we might well scan an entire input file before realizing it ain't JPEG.
711 * If an application wants to process non-JFIF files, it must seek to the
712 * SOI before calling the JPEG library.
713 */
714{
715  int c, c2;
716  INPUT_VARS(cinfo);
717
718  INPUT_BYTE(cinfo, c, return FALSE);
719  INPUT_BYTE(cinfo, c2, return FALSE);
720  if (c != 0xFF || c2 != (int) M_SOI)
721    ERREXIT2(cinfo, JERR_NO_SOI, c, c2);
722
723  cinfo->unread_marker = c2;
724
725  INPUT_SYNC(cinfo);
726  return TRUE;
727}
728
729
730/*
731 * Read markers until SOS or EOI.
732 *
733 * Returns same codes as are defined for jpeg_consume_input:
734 * JPEG_SUSPENDED, JPEG_REACHED_SOS, or JPEG_REACHED_EOI.
735 */
736
737METHODDEF(int)
738read_markers (j_decompress_ptr cinfo)
739{
740  /* Outer loop repeats once for each marker. */
741  for (;;) {
742    /* Collect the marker proper, unless we already did. */
743    /* NB: first_marker() enforces the requirement that SOI appear first. */
744    if (cinfo->unread_marker == 0) {
745      if (! cinfo->marker->saw_SOI) {
746        if (! first_marker(cinfo))
747          return JPEG_SUSPENDED;
748      } else {
749        if (! next_marker(cinfo))
750          return JPEG_SUSPENDED;
751      }
752    }
753    /* At this point cinfo->unread_marker contains the marker code and the
754     * input point is just past the marker proper, but before any parameters.
755     * A suspension will cause us to return with this state still true.
756     */
757    switch (cinfo->unread_marker) {
758    case M_SOI:
759      if (! get_soi(cinfo))
760        return JPEG_SUSPENDED;
761      break;
762
763    case M_SOF0:                /* Baseline */
764    case M_SOF1:                /* Extended sequential, Huffman */
765      if (! get_sof(cinfo, FALSE, FALSE))
766        return JPEG_SUSPENDED;
767      break;
768
769    case M_SOF2:                /* Progressive, Huffman */
770      if (! get_sof(cinfo, TRUE, FALSE))
771        return JPEG_SUSPENDED;
772      break;
773
774    case M_SOF9:                /* Extended sequential, arithmetic */
775      if (! get_sof(cinfo, FALSE, TRUE))
776        return JPEG_SUSPENDED;
777      break;
778
779    case M_SOF10:               /* Progressive, arithmetic */
780      if (! get_sof(cinfo, TRUE, TRUE))
781        return JPEG_SUSPENDED;
782      break;
783
784    /* Currently unsupported SOFn types */
785    case M_SOF3:                /* Lossless, Huffman */
786    case M_SOF5:                /* Differential sequential, Huffman */
787    case M_SOF6:                /* Differential progressive, Huffman */
788    case M_SOF7:                /* Differential lossless, Huffman */
789    case M_JPG:                 /* Reserved for JPEG extensions */
790    case M_SOF11:               /* Lossless, arithmetic */
791    case M_SOF13:               /* Differential sequential, arithmetic */
792    case M_SOF14:               /* Differential progressive, arithmetic */
793    case M_SOF15:               /* Differential lossless, arithmetic */
794      ERREXIT1(cinfo, JERR_SOF_UNSUPPORTED, cinfo->unread_marker);
795      break;
796
797    case M_SOS:
798      if (! get_sos(cinfo))
799        return JPEG_SUSPENDED;
800      cinfo->unread_marker = 0; /* processed the marker */
801      return JPEG_REACHED_SOS;
802   
803    case M_EOI:
804      TRACEMS(cinfo, 1, JTRC_EOI);
805      cinfo->unread_marker = 0; /* processed the marker */
806      return JPEG_REACHED_EOI;
807     
808    case M_DAC:
809      if (! get_dac(cinfo))
810        return JPEG_SUSPENDED;
811      break;
812     
813    case M_DHT:
814      if (! get_dht(cinfo))
815        return JPEG_SUSPENDED;
816      break;
817     
818    case M_DQT:
819      if (! get_dqt(cinfo))
820        return JPEG_SUSPENDED;
821      break;
822     
823    case M_DRI:
824      if (! get_dri(cinfo))
825        return JPEG_SUSPENDED;
826      break;
827     
828    case M_APP0:
829    case M_APP1:
830    case M_APP2:
831    case M_APP3:
832    case M_APP4:
833    case M_APP5:
834    case M_APP6:
835    case M_APP7:
836    case M_APP8:
837    case M_APP9:
838    case M_APP10:
839    case M_APP11:
840    case M_APP12:
841    case M_APP13:
842    case M_APP14:
843    case M_APP15:
844      if (! (*cinfo->marker->process_APPn[cinfo->unread_marker - (int) M_APP0]) (cinfo))
845        return JPEG_SUSPENDED;
846      break;
847     
848    case M_COM:
849      if (! (*cinfo->marker->process_COM) (cinfo))
850        return JPEG_SUSPENDED;
851      break;
852
853    case M_RST0:                /* these are all parameterless */
854    case M_RST1:
855    case M_RST2:
856    case M_RST3:
857    case M_RST4:
858    case M_RST5:
859    case M_RST6:
860    case M_RST7:
861    case M_TEM:
862      TRACEMS1(cinfo, 1, JTRC_PARMLESS_MARKER, cinfo->unread_marker);
863      break;
864
865    case M_DNL:                 /* Ignore DNL ... perhaps the wrong thing */
866      if (! skip_variable(cinfo))
867        return JPEG_SUSPENDED;
868      break;
869
870    default:                    /* must be DHP, EXP, JPGn, or RESn */
871      /* For now, we treat the reserved markers as fatal errors since they are
872       * likely to be used to signal incompatible JPEG Part 3 extensions.
873       * Once the JPEG 3 version-number marker is well defined, this code
874       * ought to change!
875       */
876      ERREXIT1(cinfo, JERR_UNKNOWN_MARKER, cinfo->unread_marker);
877      break;
878    }
879    /* Successfully processed marker, so reset state variable */
880    cinfo->unread_marker = 0;
881  } /* end loop */
882}
883
884
885/*
886 * Read a restart marker, which is expected to appear next in the datastream;
887 * if the marker is not there, take appropriate recovery action.
888 * Returns FALSE if suspension is required.
889 *
890 * This is called by the entropy decoder after it has read an appropriate
891 * number of MCUs.  cinfo->unread_marker may be nonzero if the entropy decoder
892 * has already read a marker from the data source.  Under normal conditions
893 * cinfo->unread_marker will be reset to 0 before returning; if not reset,
894 * it holds a marker which the decoder will be unable to read past.
895 */
896
897METHODDEF(boolean)
898read_restart_marker (j_decompress_ptr cinfo)
899{
900  /* Obtain a marker unless we already did. */
901  /* Note that next_marker will complain if it skips any data. */
902  if (cinfo->unread_marker == 0) {
903    if (! next_marker(cinfo))
904      return FALSE;
905  }
906
907  if (cinfo->unread_marker ==
908      ((int) M_RST0 + cinfo->marker->next_restart_num)) {
909    /* Normal case --- swallow the marker and let entropy decoder continue */
910    TRACEMS1(cinfo, 3, JTRC_RST, cinfo->marker->next_restart_num);
911    cinfo->unread_marker = 0;
912  } else {
913    /* Uh-oh, the restart markers have been messed up. */
914    /* Let the data source manager determine how to resync. */
915    if (! (*cinfo->src->resync_to_restart) (cinfo,
916                                            cinfo->marker->next_restart_num))
917      return FALSE;
918  }
919
920  /* Update next-restart state */
921  cinfo->marker->next_restart_num = (cinfo->marker->next_restart_num + 1) & 7;
922
923  return TRUE;
924}
925
926
927/*
928 * This is the default resync_to_restart method for data source managers
929 * to use if they don't have any better approach.  Some data source managers
930 * may be able to back up, or may have additional knowledge about the data
931 * which permits a more intelligent recovery strategy; such managers would
932 * presumably supply their own resync method.
933 *
934 * read_restart_marker calls resync_to_restart if it finds a marker other than
935 * the restart marker it was expecting.  (This code is *not* used unless
936 * a nonzero restart interval has been declared.)  cinfo->unread_marker is
937 * the marker code actually found (might be anything, except 0 or FF).
938 * The desired restart marker number (0..7) is passed as a parameter.
939 * This routine is supposed to apply whatever error recovery strategy seems
940 * appropriate in order to position the input stream to the next data segment.
941 * Note that cinfo->unread_marker is treated as a marker appearing before
942 * the current data-source input point; usually it should be reset to zero
943 * before returning.
944 * Returns FALSE if suspension is required.
945 *
946 * This implementation is substantially constrained by wanting to treat the
947 * input as a data stream; this means we can't back up.  Therefore, we have
948 * only the following actions to work with:
949 *   1. Simply discard the marker and let the entropy decoder resume at next
950 *      byte of file.
951 *   2. Read forward until we find another marker, discarding intervening
952 *      data.  (In theory we could look ahead within the current bufferload,
953 *      without having to discard data if we don't find the desired marker.
954 *      This idea is not implemented here, in part because it makes behavior
955 *      dependent on buffer size and chance buffer-boundary positions.)
956 *   3. Leave the marker unread (by failing to zero cinfo->unread_marker).
957 *      This will cause the entropy decoder to process an empty data segment,
958 *      inserting dummy zeroes, and then we will reprocess the marker.
959 *
960 * #2 is appropriate if we think the desired marker lies ahead, while #3 is
961 * appropriate if the found marker is a future restart marker (indicating
962 * that we have missed the desired restart marker, probably because it got
963 * corrupted).
964 * We apply #2 or #3 if the found marker is a restart marker no more than
965 * two counts behind or ahead of the expected one.  We also apply #2 if the
966 * found marker is not a legal JPEG marker code (it's certainly bogus data).
967 * If the found marker is a restart marker more than 2 counts away, we do #1
968 * (too much risk that the marker is erroneous; with luck we will be able to
969 * resync at some future point).
970 * For any valid non-restart JPEG marker, we apply #3.  This keeps us from
971 * overrunning the end of a scan.  An implementation limited to single-scan
972 * files might find it better to apply #2 for markers other than EOI, since
973 * any other marker would have to be bogus data in that case.
974 */
975
976GLOBAL(boolean)
977jpeg_resync_to_restart (j_decompress_ptr cinfo, int desired)
978{
979  int marker = cinfo->unread_marker;
980  int action = 1;
981 
982  /* Always put up a warning. */
983  WARNMS2(cinfo, JWRN_MUST_RESYNC, marker, desired);
984 
985  /* Outer loop handles repeated decision after scanning forward. */
986  for (;;) {
987    if (marker < (int) M_SOF0)
988      action = 2;               /* invalid marker */
989    else if (marker < (int) M_RST0 || marker > (int) M_RST7)
990      action = 3;               /* valid non-restart marker */
991    else {
992      if (marker == ((int) M_RST0 + ((desired+1) & 7)) ||
993          marker == ((int) M_RST0 + ((desired+2) & 7)))
994        action = 3;             /* one of the next two expected restarts */
995      else if (marker == ((int) M_RST0 + ((desired-1) & 7)) ||
996               marker == ((int) M_RST0 + ((desired-2) & 7)))
997        action = 2;             /* a prior restart, so advance */
998      else
999        action = 1;             /* desired restart or too far away */
1000    }
1001    TRACEMS2(cinfo, 4, JTRC_RECOVERY_ACTION, marker, action);
1002    switch (action) {
1003    case 1:
1004      /* Discard marker and let entropy decoder resume processing. */
1005      cinfo->unread_marker = 0;
1006      return TRUE;
1007    case 2:
1008      /* Scan to the next marker, and repeat the decision loop. */
1009      if (! next_marker(cinfo))
1010        return FALSE;
1011      marker = cinfo->unread_marker;
1012      break;
1013    case 3:
1014      /* Return without advancing past this marker. */
1015      /* Entropy decoder will be forced to process an empty segment. */
1016      return TRUE;
1017    }
1018  } /* end loop */
1019}
1020
1021
1022/*
1023 * Reset marker processing state to begin a fresh datastream.
1024 */
1025
1026METHODDEF(void)
1027reset_marker_reader (j_decompress_ptr cinfo)
1028{
1029  cinfo->comp_info = NULL;              /* until allocated by get_sof */
1030  cinfo->input_scan_number = 0;         /* no SOS seen yet */
1031  cinfo->unread_marker = 0;             /* no pending marker */
1032  cinfo->marker->saw_SOI = FALSE;       /* set internal state too */
1033  cinfo->marker->saw_SOF = FALSE;
1034  cinfo->marker->discarded_bytes = 0;
1035}
1036
1037
1038/*
1039 * Initialize the marker reader module.
1040 * This is called only once, when the decompression object is created.
1041 */
1042
1043GLOBAL(void)
1044jinit_marker_reader (j_decompress_ptr cinfo)
1045{
1046  int i;
1047
1048  /* Create subobject in permanent pool */
1049  cinfo->marker = (struct jpeg_marker_reader *)
1050    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
1051                                SIZEOF(struct jpeg_marker_reader));
1052  /* Initialize method pointers */
1053  cinfo->marker->reset_marker_reader = reset_marker_reader;
1054  cinfo->marker->read_markers = read_markers;
1055  cinfo->marker->read_restart_marker = read_restart_marker;
1056  cinfo->marker->process_COM = skip_variable;
1057  for (i = 0; i < 16; i++)
1058    cinfo->marker->process_APPn[i] = skip_variable;
1059  cinfo->marker->process_APPn[0] = get_app0;
1060  cinfo->marker->process_APPn[14] = get_app14;
1061  /* Reset marker processing state */
1062  reset_marker_reader(cinfo);
1063}
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