aboutsummaryrefslogtreecommitdiff
path: root/nxcomp/src/Jpeg.cpp
blob: 3a7871d63458abce4e4c61cdaaf949732a72505e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
/**************************************************************************/
/*                                                                        */
/* Copyright (c) 2001, 2011 NoMachine (http://www.nomachine.com)          */
/* Copyright (c) 2008-2014 Oleksandr Shneyder <o.shneyder@phoca-gmbh.de>  */
/* Copyright (c) 2014-2016 Ulrich Sibiller <uli42@gmx.de>                 */
/* Copyright (c) 2014-2016 Mihai Moldovan <ionic@ionic.de>                */
/* Copyright (c) 2011-2016 Mike Gabriel <mike.gabriel@das-netzwerkteam.de>*/
/* Copyright (c) 2015-2016 Qindel Group (http://www.qindel.com)           */
/*                                                                        */
/* NXCOMP, NX protocol compression and NX extensions to this software     */
/* are copyright of the aforementioned persons and companies.             */
/*                                                                        */
/* Redistribution and use of the present software is allowed according    */
/* to terms specified in the file LICENSE.nxcomp which comes in the       */
/* source distribution.                                                   */
/*                                                                        */
/* All rights reserved.                                                   */
/*                                                                        */
/* NOTE: This software has received contributions from various other      */
/* contributors, only the core maintainers and supporters are listed as   */
/* copyright holders. Please contact us, if you feel you should be listed */
/* as copyright holder, as well.                                          */
/*                                                                        */
/**************************************************************************/

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <X11/Xmd.h>

#ifdef ANDROID
#include <strings.h>
#endif
#include <unistd.h>
#include <setjmp.h>
#include <zlib.h>

#ifdef __cplusplus

extern "C"
{
  #include <stdio.h>
  #include <jpeglib.h>
}

#else

#include <stdio.h>
#include <jpeglib.h>

#endif

#include "Misc.h"
#include "Jpeg.h"
#include "Unpack.h"

#define PANIC
#define WARNING
#undef  TEST
#undef  DEBUG

#define RGB24_TO_PIXEL(bpp,r,g,b)                               \
   ((((CARD##bpp)(r) & 0xff) * srcRedMax + 127) / 255           \
    << srcRedShift |                                            \
    (((CARD##bpp)(g) & 0xff) * srcGreenMax + 127) / 255         \
    << srcGreenShift |                                          \
    (((CARD##bpp)(b) & 0xff) * srcBlueMax + 127) / 255          \
    << srcBlueShift)

#define RGB24_TO_PIXEL32(r,g,b)                                 \
  (((CARD32)(r) & 0xff) << srcRedShift |                        \
   ((CARD32)(g) & 0xff) << srcGreenShift |                      \
   ((CARD32)(b) & 0xff) << srcBlueShift)

//
// Functions from Unpack.cpp
//

extern int Unpack32To32(const T_colormask *colormask, const unsigned int *data,
                            unsigned int *out, unsigned int *end);

extern int Unpack24To24(const T_colormask *colormask, const unsigned char *data,
                            unsigned char *out, unsigned char *end);

extern int Unpack16To16(const T_colormask *colormask, const unsigned char *data,
                            unsigned char *out, unsigned char *end);

//
// Local functions used for the jpeg decompression.
//

static void JpegSetSrcManager(j_decompress_ptr cinfo, CARD8 *compressedData, int compressedLen);
static void JpegInitSource(j_decompress_ptr cinfo);
static void JpegTermSource(j_decompress_ptr cinfo);
static void JpegSkipInputData(j_decompress_ptr cinfo, long num_bytes);

static boolean JpegFillInputBuffer(j_decompress_ptr cinfo);

static int DecompressJpeg16(unsigned char *compressedData, int compressedLen,
                                unsigned int w, unsigned int h, unsigned char *dstBuf, int byteOrder);

static int DecompressJpeg24(unsigned char *compressedData, int compressedLen,
                                unsigned int w, unsigned int h, unsigned char *dstBuf, int byteOrder);

static int DecompressJpeg32(unsigned char *compressedData, int compressedLen,
                                unsigned int w, unsigned int h, unsigned char *dstBuf, int byteOrder);

void UnpackJpegErrorHandler(j_common_ptr cinfo) __attribute__((noreturn));

//
// Colormap stuff.
//

CARD16 srcRedMax, srcGreenMax, srcBlueMax;
CARD8  srcRedShift, srcGreenShift, srcBlueShift;

//
// Error handler.
//

static bool jpegError;

jmp_buf UnpackJpegContext;

void UnpackJpegErrorHandler(j_common_ptr cinfo)
{
  #ifdef PANIC
  *logofs << "UnpackJpegErrorHandler: PANIC! Detected error in JPEG decompression.\n"
          << logofs_flush;

  *logofs << "UnpackJpegErrorHandler: PANIC! Trying to revert to the previous context.\n"
          << logofs_flush;
  #endif

  jpegError = 1;

  longjmp(UnpackJpegContext, 1);
}

//
// Attributes used for the jpeg decompression.
//

static struct  jpeg_source_mgr jpegSrcManager;
static JOCTET  *jpegBufferPtr;
static size_t  jpegBufferLen;

static char    *tmpBuf;
static int     tmpBufSize = 0;

int UnpackJpeg(T_geometry *geometry, unsigned char method, unsigned char *srcData,
                   int srcSize, int dstBpp, int dstWidth, int dstHeight,
                       unsigned char *dstData, int dstSize)
{
  int byteOrder = geometry -> image_byte_order;

  //
  // Check if data is coming from a failed unsplit.
  //

  if (srcSize < 2 || (srcData[0] == SPLIT_PATTERN &&
          srcData[1] == SPLIT_PATTERN))
  {
    #ifdef WARNING
    *logofs << "UnpackJpeg: WARNING! Skipping unpack of dummy data.\n"
            << logofs_flush;
    #endif

    return -1;
  }

  #ifdef DEBUG
  *logofs << "UnpackJpeg: Decompression. Source size "
          << srcSize << " bits per plane " << dstBpp
          << ".\n" << logofs_flush;
  #endif

  srcRedShift   = ffs(geometry -> red_mask)   - 1;
  srcGreenShift = ffs(geometry -> green_mask) - 1;
  srcBlueShift  = ffs(geometry -> blue_mask)  - 1;

  #ifdef DEBUG
  *logofs << "UnpackJpeg: Red shift " << (int) srcRedShift
          << " green shift " << (int) srcGreenShift << " blue shift "
          << (int) srcBlueShift << ".\n" << logofs_flush;
  #endif

  srcRedMax   = geometry -> red_mask   >> srcRedShift;
  srcGreenMax = geometry -> green_mask >> srcGreenShift;
  srcBlueMax  = geometry -> blue_mask  >> srcBlueShift;

  #ifdef DEBUG
  *logofs << "UnpackJpeg: Red mask " << (void *) geometry -> red_mask
          << " green mask " << (void *) geometry -> green_mask
          << " blue mask " << (void *) geometry -> blue_mask
          << ".\n" << logofs_flush;
  #endif

  #ifdef DEBUG
  *logofs << "UnpackJpeg: Red max " << srcRedMax << " green max "
          << srcGreenMax << " blue max " << srcBlueMax
          << ".\n" << logofs_flush;
  #endif

  //
  // Make enough space in the temporary
  // buffer to have one complete row of
  // the image with 3 bytes for a pixel.
  //

  tmpBufSize = dstWidth * 3;
  tmpBuf     = new char[tmpBufSize];

  if (tmpBuf == NULL)
  {
    #ifdef PANIC
    *logofs << "UnpackJpeg: PANIC! Cannot allocate "
            << dstWidth * 3 << " bytes for Jpeg "
            << "decompressed data.\n" << logofs_flush;
    #endif

    delete [] tmpBuf;

    return -1;
  }

  int result = 1;

  switch(dstBpp)
  {
    case 8:
    {
      //
      // Simply move the data from srcData to dstData
      // taking into consideration the correct padding.
      //

      int row;

      unsigned char * dstBuff = dstData;
      unsigned char * srcBuff = srcData;

      for (row = 0; row < dstHeight; row++)
      {
        memcpy(dstBuff, srcBuff, dstWidth);

        dstBuff += RoundUp4(dstWidth);
        srcBuff += dstWidth;
      }

      break;
    }
    case 16:
    {
      result = DecompressJpeg16(srcData, srcSize, dstWidth,
                                    dstHeight, dstData, byteOrder);
      break;
    }
    case 24:
    {
      result = DecompressJpeg24(srcData, srcSize, dstWidth,
                                    dstHeight, dstData, byteOrder);
      break;
    }
    case 32:
    {
      result = DecompressJpeg32(srcData, srcSize, dstWidth,
                                    dstHeight, dstData, byteOrder);
      break;
    }
    default:
    {
      #ifdef PANIC
      *logofs << "UnpackJpeg: PANIC! Failed to decode Jpeg image. "
              << " Unsupported Bpp value " << dstBpp
              << " for the Jpeg compression"
              << ".\n" << logofs_flush;
      #endif

      delete [] tmpBuf;

      result = -1;
    }
  }

  #ifdef DEBUG
  *logofs << "UnpackJpeg: Decompression finished with result "
          << result << ".\n" << logofs_flush;
  #endif

  if (result == -1)
  {
    delete [] tmpBuf;

    #ifdef PANIC
    *logofs << "UnpackJpeg: PANIC! Failed to decode Jpeg image using "
            << dstBpp << " Bpp destination.\n" << logofs_flush;
    #endif

    return result;
  }

  //
  // Apply the correction for the brightness.
  //

  int maskMethod;

  switch(method)
  {
    case PACK_JPEG_8_COLORS:
    {
      maskMethod = MASK_8_COLORS;

      break;
    }
    case PACK_JPEG_64_COLORS:
    {
      maskMethod = MASK_64_COLORS;

      break;
    }
    case PACK_JPEG_256_COLORS:
    {
      maskMethod = MASK_256_COLORS;

      break;
    }
    case PACK_JPEG_512_COLORS:
    {
      maskMethod = MASK_512_COLORS;

      break;
    }
    case PACK_JPEG_4K_COLORS:
    {
      maskMethod = MASK_4K_COLORS;

      break;
    }
    case PACK_JPEG_32K_COLORS:
    {
      maskMethod = MASK_32K_COLORS;

      break;
    }
    case PACK_JPEG_64K_COLORS:
    {
      maskMethod = MASK_64K_COLORS;

      break;
    }
    case PACK_JPEG_256K_COLORS:
    {
      maskMethod = MASK_256K_COLORS;

      break;
    }
    case PACK_JPEG_2M_COLORS:
    {
      maskMethod = MASK_2M_COLORS;

      break;
    }
    case PACK_JPEG_16M_COLORS:
    {
      maskMethod = MASK_16M_COLORS;

      break;
    }
    default:
    {
      delete [] tmpBuf;

      return -1;
    }
  }

  const T_colormask *colorMask = MethodColorMask(maskMethod);

  unsigned char *dstBuff = dstData;

  switch (dstBpp)
  {
    case 16:
    {
      Unpack16To16(colorMask, dstBuff, dstBuff, dstBuff + dstSize);

      break;
    }
    case 24:
    {
      break;
    }
    case 32:
    {
      Unpack32To32(colorMask, (unsigned int *) dstBuff, (unsigned int *) dstBuff,
                       (unsigned int *) (dstBuff + dstSize));
      break;
    }
    default:
    {
      delete [] tmpBuf;

      return -1;
    }
  }

  delete [] tmpBuf;

  return 1;
}

//
// Functions that actually do the Jpeg decompression.
//

int DecompressJpeg16(unsigned char *compressedData, int compressedLen,
                         unsigned int w, unsigned int h, unsigned char *dstBuf, int byteOrder)
{
  struct jpeg_decompress_struct cinfo;
  struct jpeg_error_mgr jerr;
  unsigned char *data;
  JSAMPROW rowPointer[1];

  unsigned int dx = 0;
  unsigned int dy = 0;

  #ifdef DEBUG
  *logofs << "DecompressJpeg16: Decompressing with length "
          << compressedLen << " width " << w << " height "
          << h << ".\n" << logofs_flush;
  #endif

  jpegError = 0;

  cinfo.err = jpeg_std_error(&jerr);

  jerr.error_exit = UnpackJpegErrorHandler;

  if (setjmp(UnpackJpegContext) == 1)
  {
    #ifdef TEST
    *logofs << "DecompressJpeg16: Out of the long jump with error '"
            << jpegError << "'.\n" << logofs_flush;
    #endif

    goto AbortDecompressJpeg16;
  }

  jpeg_create_decompress(&cinfo);

  if (jpegError) goto AbortDecompressJpeg16;

  JpegSetSrcManager(&cinfo, compressedData, compressedLen);

  jpeg_read_header(&cinfo, TRUE);

  if (jpegError) goto AbortDecompressJpeg16;

  cinfo.out_color_space = JCS_RGB;

  jpeg_start_decompress(&cinfo);

  if (jpegError) goto AbortDecompressJpeg16;

  if (cinfo.output_width != w ||
          cinfo.output_height != h ||
              cinfo.output_components != 3)
  {
    #ifdef PANIC
    *logofs << "DecompressJpeg16: PANIC! Wrong JPEG data received.\n"
            << logofs_flush;
    #endif

    jpeg_destroy_decompress(&cinfo);

    return -1;
  }

  //
  // PixelPtr points to dstBuf which is
  // already padded correctly for the final
  // image to put
  //

  data = dstBuf;

  rowPointer[0] = (JSAMPROW) tmpBuf;

  unsigned long pixel;

  while (cinfo.output_scanline < cinfo.output_height)
  {
    jpeg_read_scanlines(&cinfo, rowPointer, 1);

    if (jpegError) goto AbortDecompressJpeg16;

    for (dx = 0; dx < w; dx++)
    {
      pixel = RGB24_TO_PIXEL(16, tmpBuf[dx * 3], tmpBuf[dx * 3 + 1],
                                 tmpBuf[dx * 3 + 2]);

      //
      // Follow the server byte order when arranging data.
      //

      if (byteOrder == LSBFirst)
      {
        data[0] = (unsigned char) (pixel & 0xff);
        data[1] = (unsigned char) ((pixel >> 8) & 0xff);
      }
      else
      {
        data[1] = (unsigned char) (pixel & 0xff);
        data[0] = (unsigned char) ((pixel >> 8) & 0xff);
      }

      data += 2;
    }

    //
    // Move data at the beginning of the
    // next line.
    //

    data = data + (RoundUp4(w * 2) - w * 2);

    dy++;
  }

  AbortDecompressJpeg16:

  if (jpegError == 0)
  {
    jpeg_finish_decompress(&cinfo);
  }

  jpeg_destroy_decompress(&cinfo);

  if (jpegError == 1)
  {
    #ifdef PANIC
    *logofs << "DecompressJpeg16: Failed to decompress JPEG image.\n"
            << logofs_flush;
    #endif

    return -1;
  }

  #ifdef TEST
  *logofs << "DecompressJpeg16: Decompression finished with "
          << dy << " lines handled.\n" << logofs_flush;
  #endif

  return 1;
}

int DecompressJpeg24(unsigned char *compressedData, int compressedLen,
                         unsigned int w, unsigned int h, unsigned char *dstBuf, int byteOrder)
{
  struct jpeg_decompress_struct cinfo;
  struct jpeg_error_mgr jerr;
  CARD8 *pixelPtr = NULL;
  JSAMPROW rowPointer[1];

  unsigned int dx = 0;
  unsigned int dy = 0;

  #ifdef TEST
  *logofs << "DecompressJpeg24: Decompressing with length "
          << compressedLen << " width " << w << " height "
          << h << ".\n" << logofs_flush;
  #endif

  jpegError = 0;

  cinfo.err = jpeg_std_error(&jerr);

  jerr.error_exit = UnpackJpegErrorHandler;

  if (setjmp(UnpackJpegContext) == 1)
  {
    #ifdef TEST
    *logofs << "DecompressJpeg24: Out of the long jump with error '"
            << jpegError << "'.\n" << logofs_flush;
    #endif

    goto AbortDecompressJpeg24;
  }

  jpeg_create_decompress(&cinfo);

  if (jpegError) goto AbortDecompressJpeg24;

  JpegSetSrcManager(&cinfo, compressedData, compressedLen);

  jpeg_read_header(&cinfo, TRUE);

  if (jpegError) goto AbortDecompressJpeg24;

  cinfo.out_color_space = JCS_RGB;

  jpeg_start_decompress(&cinfo);

  if (jpegError) goto AbortDecompressJpeg24;

  if (cinfo.output_width != w ||
          cinfo.output_height != h ||
              cinfo.output_components != 3)
  {
    #ifdef PANIC
    *logofs << "DecompressJpeg24: PANIC! Wrong JPEG data received.\n"
            << logofs_flush;
    #endif

    jpeg_destroy_decompress(&cinfo);

    return -1;
  }

  //
  // PixelPtr points to dstBuf which is
  // already padded correctly for the final
  // image to put.
  //

  pixelPtr = (CARD8 *) dstBuf;

  rowPointer[0] = (JSAMPROW) tmpBuf;

  while (cinfo.output_scanline < cinfo.output_height)
  {
    jpeg_read_scanlines(&cinfo, rowPointer, 1);

    if (jpegError) goto AbortDecompressJpeg24;

    for (dx = 0; dx < w; dx++)
    {
      //
      // Follow the server byte order when arranging data.
      //

      if (byteOrder == LSBFirst)
      {
        pixelPtr[0] = tmpBuf[dx * 3];
        pixelPtr[1] = tmpBuf[dx * 3 + 1];
        pixelPtr[2] = tmpBuf[dx * 3 + 2];
      }
      else
      {
        pixelPtr[2] = tmpBuf[dx * 3];
        pixelPtr[1] = tmpBuf[dx * 3 + 1];
        pixelPtr[0] = tmpBuf[dx * 3 + 2];
      }

      pixelPtr += 3;
    }

    //
    // Go to the next line.
    //

    pixelPtr = (CARD8 *) (((char *) pixelPtr) + (RoundUp4(w * 3) - w * 3));

    dy++;
  }

  AbortDecompressJpeg24:

  if (jpegError == 0)
  {
    jpeg_finish_decompress(&cinfo);
  }

  jpeg_destroy_decompress(&cinfo);

  if (jpegError == 1)
  {
    #ifdef PANIC
    *logofs << "DecompressJpeg24: Failed to decompress JPEG image.\n"
            << logofs_flush;
    #endif

    return -1;
  }

  #ifdef TEST
  *logofs << "DecompressJpeg24: Decompression finished with "
          << dy << " lines handled.\n" << logofs_flush;
  #endif

  return 1;
}

int DecompressJpeg32(unsigned char *compressedData, int compressedLen,
                         unsigned int w, unsigned int h, unsigned char *dstBuf, int byteOrder)
{
  struct jpeg_decompress_struct cinfo;
  struct jpeg_error_mgr jerr;
  unsigned char *data;
  JSAMPROW rowPointer[1];

  unsigned int dx = 0;
  unsigned int dy = 0;

  #ifdef TEST
  *logofs << "DecompressJpeg32: Decompressing with length "
          << compressedLen << " width " << w << " height "
          << h << ".\n" << logofs_flush;
  #endif

  jpegError = 0;

  cinfo.err = jpeg_std_error(&jerr);

  jerr.error_exit = UnpackJpegErrorHandler;

  if (setjmp(UnpackJpegContext) == 1)
  {
    #ifdef TEST
    *logofs << "DecompressJpeg32: Out of the long jump with error '"
            << jpegError << "'.\n" << logofs_flush;
    #endif

    goto AbortDecompressJpeg32;
  }

  jpeg_create_decompress(&cinfo);

  if (jpegError) goto AbortDecompressJpeg32;

  JpegSetSrcManager(&cinfo, compressedData, compressedLen);

  jpeg_read_header(&cinfo, TRUE);

  if (jpegError) goto AbortDecompressJpeg32;

  cinfo.out_color_space = JCS_RGB;

  jpeg_start_decompress(&cinfo);

  if (jpegError) goto AbortDecompressJpeg32;

  if (cinfo.output_width != w ||
          cinfo.output_height != h ||
              cinfo.output_components != 3)
  {
    #ifdef PANIC
    *logofs << "DecompressJpeg32 : PANIC! Wrong JPEG data received.\n"
            << logofs_flush;
    #endif

    jpeg_destroy_decompress(&cinfo);

    return -1;
  }

  //
  // PixelPtr points to dstBuf which is
  // already padded correctly for the final
  // image to put
  //

  data = dstBuf;

  rowPointer[0] = (JSAMPROW) tmpBuf;

  unsigned long pixel;

  int i;

  while (cinfo.output_scanline < cinfo.output_height)
  {
    jpeg_read_scanlines(&cinfo, rowPointer, 1);

    if (jpegError) goto AbortDecompressJpeg32;

    for (dx = 0; dx < w; dx++)
    {
      pixel = RGB24_TO_PIXEL(32, tmpBuf[dx * 3], tmpBuf[dx * 3 + 1],
                                 tmpBuf[dx * 3 + 2]);

      //
      // Follow the server byte order when arranging data.
      //

      if (byteOrder == LSBFirst)
      {
        for (i = 0; i < 4; i++)
        {
          data[i] = (unsigned char)(pixel & 0xff);
          pixel >>= 8;
        }
      }
      else
      {
        for (i = 3; i >= 0; i--)
        {
          data[i] = (unsigned char) (pixel & 0xff);
          pixel >>= 8;
        }
      }

      data += 4;
    }

    dy++;
  }

  AbortDecompressJpeg32:

  if (jpegError == 0)
  {
    jpeg_finish_decompress(&cinfo);
  }

  jpeg_destroy_decompress(&cinfo);

  if (jpegError == 1)
  {
    #ifdef PANIC
    *logofs << "DecompressJpeg32: Failed to decompress JPEG image.\n"
            << logofs_flush;
    #endif

    return -1;
  }

  #ifdef TEST
  *logofs << "DecompressJpeg32: Decompression finished with "
          << dy << " lines handled.\n" << logofs_flush;
  #endif

  return 1;
}

static void JpegInitSource(j_decompress_ptr cinfo)
{
  jpegError = 0;
}

static boolean JpegFillInputBuffer(j_decompress_ptr cinfo)
{
  jpegError = 1;

  jpegSrcManager.bytes_in_buffer = jpegBufferLen;
  jpegSrcManager.next_input_byte = (JOCTET *)jpegBufferPtr;

  return TRUE;
}

static void JpegSkipInputData(j_decompress_ptr cinfo, long num_bytes)
{
  if (num_bytes < 0 || (unsigned long) num_bytes > jpegSrcManager.bytes_in_buffer)
  {
    jpegError = 1;

    jpegSrcManager.bytes_in_buffer = jpegBufferLen;
    jpegSrcManager.next_input_byte = (JOCTET *)jpegBufferPtr;
  }
  else
  {
    jpegSrcManager.next_input_byte += (size_t) num_bytes;
    jpegSrcManager.bytes_in_buffer -= (size_t) num_bytes;
  }
}

static void JpegTermSource(j_decompress_ptr cinfo)
{
}

static void JpegSetSrcManager(j_decompress_ptr cinfo,
                                  CARD8 *compressedData,
                                      int compressedLen)
{
  jpegBufferPtr = (JOCTET *) compressedData;
  jpegBufferLen = (size_t) compressedLen;

  jpegSrcManager.init_source       = JpegInitSource;
  jpegSrcManager.fill_input_buffer = JpegFillInputBuffer;
  jpegSrcManager.skip_input_data   = JpegSkipInputData;
  jpegSrcManager.resync_to_restart = jpeg_resync_to_restart;
  jpegSrcManager.term_source       = JpegTermSource;
  jpegSrcManager.next_input_byte   = jpegBufferPtr;
  jpegSrcManager.bytes_in_buffer   = jpegBufferLen;

  cinfo->src = &jpegSrcManager;
}