summaryrefslogtreecommitdiff
path: root/core/fxcodec/codec/fx_codec_flate.cpp
blob: c5611cc27a14b9aa59333c1592dfd5d2b0749aea (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
// Copyright 2014 PDFium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com

#include "core/fxcodec/codec/codec_int.h"

#include <algorithm>
#include <memory>

#include "core/fxcodec/fx_codec.h"
#include "core/fxcrt/fx_ext.h"
#include "third_party/zlib_v128/zlib.h"

extern "C" {
static void* my_alloc_func(void* opaque,
                           unsigned int items,
                           unsigned int size) {
  return FX_Alloc2D(uint8_t, items, size);
}
static void my_free_func(void* opaque, void* address) {
  FX_Free(address);
}
static int FPDFAPI_FlateGetTotalOut(void* context) {
  return ((z_stream*)context)->total_out;
}
static int FPDFAPI_FlateGetTotalIn(void* context) {
  return ((z_stream*)context)->total_in;
}

static bool FPDFAPI_FlateCompress(unsigned char* dest_buf,
                                  unsigned long* dest_size,
                                  const unsigned char* src_buf,
                                  unsigned long src_size) {
  return compress(dest_buf, dest_size, src_buf, src_size) == Z_OK;
}

void* FPDFAPI_FlateInit(void* (*alloc_func)(void*, unsigned int, unsigned int),
                        void (*free_func)(void*, void*)) {
  z_stream* p = (z_stream*)alloc_func(0, 1, sizeof(z_stream));
  if (!p)
    return nullptr;

  FXSYS_memset(p, 0, sizeof(z_stream));
  p->zalloc = alloc_func;
  p->zfree = free_func;
  inflateInit(p);
  return p;
}

void FPDFAPI_FlateInput(void* context,
                        const unsigned char* src_buf,
                        unsigned int src_size) {
  ((z_stream*)context)->next_in = (unsigned char*)src_buf;
  ((z_stream*)context)->avail_in = src_size;
}

int FPDFAPI_FlateOutput(void* context,
                        unsigned char* dest_buf,
                        unsigned int dest_size) {
  ((z_stream*)context)->next_out = dest_buf;
  ((z_stream*)context)->avail_out = dest_size;
  unsigned int pre_pos = (unsigned int)FPDFAPI_FlateGetTotalOut(context);
  int ret = inflate((z_stream*)context, Z_SYNC_FLUSH);
  unsigned int post_pos = (unsigned int)FPDFAPI_FlateGetTotalOut(context);
  unsigned int written = post_pos - pre_pos;
  if (written < dest_size) {
    FXSYS_memset(dest_buf + written, '\0', dest_size - written);
  }
  return ret;
}

int FPDFAPI_FlateGetAvailIn(void* context) {
  return ((z_stream*)context)->avail_in;
}

int FPDFAPI_FlateGetAvailOut(void* context) {
  return ((z_stream*)context)->avail_out;
}

void FPDFAPI_FlateEnd(void* context) {
  inflateEnd((z_stream*)context);
  ((z_stream*)context)->zfree(0, context);
}

}  // extern "C"

namespace {

class CLZWDecoder {
 public:
  int Decode(uint8_t* output,
             uint32_t& outlen,
             const uint8_t* input,
             uint32_t& size,
             bool bEarlyChange);

 private:
  void AddCode(uint32_t prefix_code, uint8_t append_char);
  void DecodeString(uint32_t code);

  uint32_t m_InPos;
  uint32_t m_OutPos;
  uint8_t* m_pOutput;
  const uint8_t* m_pInput;
  bool m_Early;
  uint32_t m_CodeArray[5021];
  uint32_t m_nCodes;
  uint8_t m_DecodeStack[4000];
  uint32_t m_StackLen;
  int m_CodeLen;
};

void CLZWDecoder::AddCode(uint32_t prefix_code, uint8_t append_char) {
  if (m_nCodes + m_Early == 4094) {
    return;
  }
  m_CodeArray[m_nCodes++] = (prefix_code << 16) | append_char;
  if (m_nCodes + m_Early == 512 - 258) {
    m_CodeLen = 10;
  } else if (m_nCodes + m_Early == 1024 - 258) {
    m_CodeLen = 11;
  } else if (m_nCodes + m_Early == 2048 - 258) {
    m_CodeLen = 12;
  }
}
void CLZWDecoder::DecodeString(uint32_t code) {
  while (1) {
    int index = code - 258;
    if (index < 0 || index >= (int)m_nCodes) {
      break;
    }
    uint32_t data = m_CodeArray[index];
    if (m_StackLen >= sizeof(m_DecodeStack)) {
      return;
    }
    m_DecodeStack[m_StackLen++] = (uint8_t)data;
    code = data >> 16;
  }
  if (m_StackLen >= sizeof(m_DecodeStack)) {
    return;
  }
  m_DecodeStack[m_StackLen++] = (uint8_t)code;
}
int CLZWDecoder::Decode(uint8_t* dest_buf,
                        uint32_t& dest_size,
                        const uint8_t* src_buf,
                        uint32_t& src_size,
                        bool bEarlyChange) {
  m_CodeLen = 9;
  m_InPos = 0;
  m_OutPos = 0;
  m_pInput = src_buf;
  m_pOutput = dest_buf;
  m_Early = bEarlyChange ? 1 : 0;
  m_nCodes = 0;
  uint32_t old_code = (uint32_t)-1;
  uint8_t last_char = 0;
  while (1) {
    if (m_InPos + m_CodeLen > src_size * 8) {
      break;
    }
    int byte_pos = m_InPos / 8;
    int bit_pos = m_InPos % 8, bit_left = m_CodeLen;
    uint32_t code = 0;
    if (bit_pos) {
      bit_left -= 8 - bit_pos;
      code = (m_pInput[byte_pos++] & ((1 << (8 - bit_pos)) - 1)) << bit_left;
    }
    if (bit_left < 8) {
      code |= m_pInput[byte_pos] >> (8 - bit_left);
    } else {
      bit_left -= 8;
      code |= m_pInput[byte_pos++] << bit_left;
      if (bit_left) {
        code |= m_pInput[byte_pos] >> (8 - bit_left);
      }
    }
    m_InPos += m_CodeLen;
    if (code < 256) {
      if (m_OutPos == dest_size) {
        return -5;
      }
      if (m_pOutput) {
        m_pOutput[m_OutPos] = (uint8_t)code;
      }
      m_OutPos++;
      last_char = (uint8_t)code;
      if (old_code != (uint32_t)-1) {
        AddCode(old_code, last_char);
      }
      old_code = code;
    } else if (code == 256) {
      m_CodeLen = 9;
      m_nCodes = 0;
      old_code = (uint32_t)-1;
    } else if (code == 257) {
      break;
    } else {
      if (old_code == (uint32_t)-1) {
        return 2;
      }
      m_StackLen = 0;
      if (code >= m_nCodes + 258) {
        if (m_StackLen < sizeof(m_DecodeStack)) {
          m_DecodeStack[m_StackLen++] = last_char;
        }
        DecodeString(old_code);
      } else {
        DecodeString(code);
      }
      if (m_OutPos + m_StackLen > dest_size) {
        return -5;
      }
      if (m_pOutput) {
        for (uint32_t i = 0; i < m_StackLen; i++) {
          m_pOutput[m_OutPos + i] = m_DecodeStack[m_StackLen - i - 1];
        }
      }
      m_OutPos += m_StackLen;
      last_char = m_DecodeStack[m_StackLen - 1];
      if (old_code < 256) {
        AddCode(old_code, last_char);
      } else if (old_code - 258 >= m_nCodes) {
        dest_size = m_OutPos;
        src_size = (m_InPos + 7) / 8;
        return 0;
      } else {
        AddCode(old_code, last_char);
      }
      old_code = code;
    }
  }
  dest_size = m_OutPos;
  src_size = (m_InPos + 7) / 8;
  return 0;
}

uint8_t PathPredictor(int a, int b, int c) {
  int p = a + b - c;
  int pa = FXSYS_abs(p - a);
  int pb = FXSYS_abs(p - b);
  int pc = FXSYS_abs(p - c);
  if (pa <= pb && pa <= pc)
    return (uint8_t)a;
  if (pb <= pc)
    return (uint8_t)b;
  return (uint8_t)c;
}

void PNG_PredictorEncode(uint8_t** data_buf, uint32_t* data_size) {
  const int row_size = 7;
  const int row_count = (*data_size + row_size - 1) / row_size;
  const int last_row_size = *data_size % row_size;
  uint8_t* dest_buf = FX_Alloc2D(uint8_t, row_size + 1, row_count);
  int byte_cnt = 0;
  uint8_t* pSrcData = *data_buf;
  uint8_t* pDestData = dest_buf;
  for (int row = 0; row < row_count; row++) {
    for (int byte = 0; byte < row_size && byte_cnt < (int)*data_size; byte++) {
      pDestData[0] = 2;
      uint8_t up = 0;
      if (row)
        up = pSrcData[byte - row_size];
      pDestData[byte + 1] = pSrcData[byte] - up;
      ++byte_cnt;
    }
    pDestData += (row_size + 1);
    pSrcData += row_size;
  }
  FX_Free(*data_buf);
  *data_buf = dest_buf;
  *data_size = (row_size + 1) * row_count -
               (last_row_size > 0 ? (row_size - last_row_size) : 0);
}

void PNG_PredictLine(uint8_t* pDestData,
                     const uint8_t* pSrcData,
                     const uint8_t* pLastLine,
                     int bpc,
                     int nColors,
                     int nPixels) {
  int row_size = (nPixels * bpc * nColors + 7) / 8;
  int BytesPerPixel = (bpc * nColors + 7) / 8;
  uint8_t tag = pSrcData[0];
  if (tag == 0) {
    FXSYS_memmove(pDestData, pSrcData + 1, row_size);
    return;
  }
  for (int byte = 0; byte < row_size; byte++) {
    uint8_t raw_byte = pSrcData[byte + 1];
    switch (tag) {
      case 1: {
        uint8_t left = 0;
        if (byte >= BytesPerPixel) {
          left = pDestData[byte - BytesPerPixel];
        }
        pDestData[byte] = raw_byte + left;
        break;
      }
      case 2: {
        uint8_t up = 0;
        if (pLastLine) {
          up = pLastLine[byte];
        }
        pDestData[byte] = raw_byte + up;
        break;
      }
      case 3: {
        uint8_t left = 0;
        if (byte >= BytesPerPixel) {
          left = pDestData[byte - BytesPerPixel];
        }
        uint8_t up = 0;
        if (pLastLine) {
          up = pLastLine[byte];
        }
        pDestData[byte] = raw_byte + (up + left) / 2;
        break;
      }
      case 4: {
        uint8_t left = 0;
        if (byte >= BytesPerPixel) {
          left = pDestData[byte - BytesPerPixel];
        }
        uint8_t up = 0;
        if (pLastLine) {
          up = pLastLine[byte];
        }
        uint8_t upper_left = 0;
        if (byte >= BytesPerPixel && pLastLine) {
          upper_left = pLastLine[byte - BytesPerPixel];
        }
        pDestData[byte] = raw_byte + PathPredictor(left, up, upper_left);
        break;
      }
      default:
        pDestData[byte] = raw_byte;
        break;
    }
  }
}

bool PNG_Predictor(uint8_t*& data_buf,
                   uint32_t& data_size,
                   int Colors,
                   int BitsPerComponent,
                   int Columns) {
  const int BytesPerPixel = (Colors * BitsPerComponent + 7) / 8;
  const int row_size = (Colors * BitsPerComponent * Columns + 7) / 8;
  if (row_size <= 0)
    return false;
  const int row_count = (data_size + row_size) / (row_size + 1);
  if (row_count <= 0)
    return false;
  const int last_row_size = data_size % (row_size + 1);
  uint8_t* dest_buf = FX_Alloc2D(uint8_t, row_size, row_count);
  int byte_cnt = 0;
  uint8_t* pSrcData = data_buf;
  uint8_t* pDestData = dest_buf;
  for (int row = 0; row < row_count; row++) {
    uint8_t tag = pSrcData[0];
    byte_cnt++;
    if (tag == 0) {
      int move_size = row_size;
      if ((row + 1) * (move_size + 1) > (int)data_size) {
        move_size = last_row_size - 1;
      }
      FXSYS_memmove(pDestData, pSrcData + 1, move_size);
      pSrcData += move_size + 1;
      pDestData += move_size;
      byte_cnt += move_size;
      continue;
    }
    for (int byte = 0; byte < row_size && byte_cnt < (int)data_size; byte++) {
      uint8_t raw_byte = pSrcData[byte + 1];
      switch (tag) {
        case 1: {
          uint8_t left = 0;
          if (byte >= BytesPerPixel) {
            left = pDestData[byte - BytesPerPixel];
          }
          pDestData[byte] = raw_byte + left;
          break;
        }
        case 2: {
          uint8_t up = 0;
          if (row) {
            up = pDestData[byte - row_size];
          }
          pDestData[byte] = raw_byte + up;
          break;
        }
        case 3: {
          uint8_t left = 0;
          if (byte >= BytesPerPixel) {
            left = pDestData[byte - BytesPerPixel];
          }
          uint8_t up = 0;
          if (row) {
            up = pDestData[byte - row_size];
          }
          pDestData[byte] = raw_byte + (up + left) / 2;
          break;
        }
        case 4: {
          uint8_t left = 0;
          if (byte >= BytesPerPixel) {
            left = pDestData[byte - BytesPerPixel];
          }
          uint8_t up = 0;
          if (row) {
            up = pDestData[byte - row_size];
          }
          uint8_t upper_left = 0;
          if (byte >= BytesPerPixel && row) {
            upper_left = pDestData[byte - row_size - BytesPerPixel];
          }
          pDestData[byte] = raw_byte + PathPredictor(left, up, upper_left);
          break;
        }
        default:
          pDestData[byte] = raw_byte;
          break;
      }
      byte_cnt++;
    }
    pSrcData += row_size + 1;
    pDestData += row_size;
  }
  FX_Free(data_buf);
  data_buf = dest_buf;
  data_size = row_size * row_count -
              (last_row_size > 0 ? (row_size + 1 - last_row_size) : 0);
  return true;
}

void TIFF_PredictLine(uint8_t* dest_buf,
                      uint32_t row_size,
                      int BitsPerComponent,
                      int Colors,
                      int Columns) {
  if (BitsPerComponent == 1) {
    int row_bits = std::min(BitsPerComponent * Colors * Columns,
                            pdfium::base::checked_cast<int>(row_size * 8));
    int index_pre = 0;
    int col_pre = 0;
    for (int i = 1; i < row_bits; i++) {
      int col = i % 8;
      int index = i / 8;
      if (((dest_buf[index] >> (7 - col)) & 1) ^
          ((dest_buf[index_pre] >> (7 - col_pre)) & 1)) {
        dest_buf[index] |= 1 << (7 - col);
      } else {
        dest_buf[index] &= ~(1 << (7 - col));
      }
      index_pre = index;
      col_pre = col;
    }
    return;
  }
  int BytesPerPixel = BitsPerComponent * Colors / 8;
  if (BitsPerComponent == 16) {
    for (uint32_t i = BytesPerPixel; i < row_size; i += 2) {
      uint16_t pixel =
          (dest_buf[i - BytesPerPixel] << 8) | dest_buf[i - BytesPerPixel + 1];
      pixel += (dest_buf[i] << 8) | dest_buf[i + 1];
      dest_buf[i] = pixel >> 8;
      dest_buf[i + 1] = (uint8_t)pixel;
    }
  } else {
    for (uint32_t i = BytesPerPixel; i < row_size; i++) {
      dest_buf[i] += dest_buf[i - BytesPerPixel];
    }
  }
}

bool TIFF_Predictor(uint8_t*& data_buf,
                    uint32_t& data_size,
                    int Colors,
                    int BitsPerComponent,
                    int Columns) {
  int row_size = (Colors * BitsPerComponent * Columns + 7) / 8;
  if (row_size == 0)
    return false;
  const int row_count = (data_size + row_size - 1) / row_size;
  const int last_row_size = data_size % row_size;
  for (int row = 0; row < row_count; row++) {
    uint8_t* scan_line = data_buf + row * row_size;
    if ((row + 1) * row_size > (int)data_size) {
      row_size = last_row_size;
    }
    TIFF_PredictLine(scan_line, row_size, BitsPerComponent, Colors, Columns);
  }
  return true;
}

void FlateUncompress(const uint8_t* src_buf,
                     uint32_t src_size,
                     uint32_t orig_size,
                     uint8_t*& dest_buf,
                     uint32_t& dest_size,
                     uint32_t& offset) {
  uint32_t guess_size = orig_size ? orig_size : src_size * 2;
  const uint32_t kStepSize = 10240;
  uint32_t alloc_step = orig_size ? kStepSize : std::min(src_size, kStepSize);
  static const uint32_t kMaxInitialAllocSize = 10000000;
  if (guess_size > kMaxInitialAllocSize) {
    guess_size = kMaxInitialAllocSize;
    alloc_step = kMaxInitialAllocSize;
  }
  uint32_t buf_size = guess_size;
  uint32_t last_buf_size = buf_size;

  dest_buf = nullptr;
  dest_size = 0;
  void* context = FPDFAPI_FlateInit(my_alloc_func, my_free_func);
  if (!context)
    return;

  std::unique_ptr<uint8_t, FxFreeDeleter> guess_buf(
      FX_Alloc(uint8_t, guess_size + 1));
  guess_buf.get()[guess_size] = '\0';

  FPDFAPI_FlateInput(context, src_buf, src_size);

  if (src_size < kStepSize) {
    // This is the old implementation.
    uint8_t* cur_buf = guess_buf.get();
    while (1) {
      int32_t ret = FPDFAPI_FlateOutput(context, cur_buf, buf_size);
      if (ret != Z_OK)
        break;
      int32_t avail_buf_size = FPDFAPI_FlateGetAvailOut(context);
      if (avail_buf_size != 0)
        break;

      uint32_t old_size = guess_size;
      guess_size += alloc_step;
      if (guess_size < old_size || guess_size + 1 < guess_size) {
        FPDFAPI_FlateEnd(context);
        return;
      }

      {
        uint8_t* new_buf =
            FX_Realloc(uint8_t, guess_buf.release(), guess_size + 1);
        guess_buf.reset(new_buf);
      }
      guess_buf.get()[guess_size] = '\0';
      cur_buf = guess_buf.get() + old_size;
      buf_size = guess_size - old_size;
    }
    dest_size = FPDFAPI_FlateGetTotalOut(context);
    offset = FPDFAPI_FlateGetTotalIn(context);
    if (guess_size / 2 > dest_size) {
      {
        uint8_t* new_buf =
            FX_Realloc(uint8_t, guess_buf.release(), dest_size + 1);
        guess_buf.reset(new_buf);
      }
      guess_size = dest_size;
      guess_buf.get()[guess_size] = '\0';
    }
    dest_buf = guess_buf.release();
  } else {
    CFX_ArrayTemplate<uint8_t*> result_tmp_bufs;
    uint8_t* cur_buf = guess_buf.release();
    while (1) {
      int32_t ret = FPDFAPI_FlateOutput(context, cur_buf, buf_size);
      int32_t avail_buf_size = FPDFAPI_FlateGetAvailOut(context);
      if (ret != Z_OK) {
        last_buf_size = buf_size - avail_buf_size;
        result_tmp_bufs.Add(cur_buf);
        break;
      }
      if (avail_buf_size != 0) {
        last_buf_size = buf_size - avail_buf_size;
        result_tmp_bufs.Add(cur_buf);
        break;
      }

      result_tmp_bufs.Add(cur_buf);
      cur_buf = FX_Alloc(uint8_t, buf_size + 1);
      cur_buf[buf_size] = '\0';
    }
    dest_size = FPDFAPI_FlateGetTotalOut(context);
    offset = FPDFAPI_FlateGetTotalIn(context);
    if (result_tmp_bufs.GetSize() == 1) {
      dest_buf = result_tmp_bufs[0];
    } else {
      uint8_t* result_buf = FX_Alloc(uint8_t, dest_size);
      uint32_t result_pos = 0;
      for (int32_t i = 0; i < result_tmp_bufs.GetSize(); i++) {
        uint8_t* tmp_buf = result_tmp_bufs[i];
        uint32_t tmp_buf_size = buf_size;
        if (i == result_tmp_bufs.GetSize() - 1) {
          tmp_buf_size = last_buf_size;
        }
        FXSYS_memcpy(result_buf + result_pos, tmp_buf, tmp_buf_size);
        result_pos += tmp_buf_size;
        FX_Free(result_tmp_bufs[i]);
      }
      dest_buf = result_buf;
    }
  }
  FPDFAPI_FlateEnd(context);
}

}  // namespace

class CCodec_FlateScanlineDecoder : public CCodec_ScanlineDecoder {
 public:
  CCodec_FlateScanlineDecoder();
  ~CCodec_FlateScanlineDecoder() override;

  void Create(const uint8_t* src_buf,
              uint32_t src_size,
              int width,
              int height,
              int nComps,
              int bpc,
              int predictor,
              int Colors,
              int BitsPerComponent,
              int Columns);

  // CCodec_ScanlineDecoder
  bool v_Rewind() override;
  uint8_t* v_GetNextLine() override;
  uint32_t GetSrcOffset() override;

  void* m_pFlate;
  const uint8_t* m_SrcBuf;
  uint32_t m_SrcSize;
  uint8_t* m_pScanline;
  uint8_t* m_pLastLine;
  uint8_t* m_pPredictBuffer;
  uint8_t* m_pPredictRaw;
  int m_Predictor;
  int m_Colors;
  int m_BitsPerComponent;
  int m_Columns;
  uint32_t m_PredictPitch;
  size_t m_LeftOver;
};

CCodec_FlateScanlineDecoder::CCodec_FlateScanlineDecoder() {
  m_pFlate = nullptr;
  m_pScanline = nullptr;
  m_pLastLine = nullptr;
  m_pPredictBuffer = nullptr;
  m_pPredictRaw = nullptr;
  m_LeftOver = 0;
}
CCodec_FlateScanlineDecoder::~CCodec_FlateScanlineDecoder() {
  FX_Free(m_pScanline);
  FX_Free(m_pLastLine);
  FX_Free(m_pPredictBuffer);
  FX_Free(m_pPredictRaw);
  if (m_pFlate) {
    FPDFAPI_FlateEnd(m_pFlate);
  }
}
void CCodec_FlateScanlineDecoder::Create(const uint8_t* src_buf,
                                         uint32_t src_size,
                                         int width,
                                         int height,
                                         int nComps,
                                         int bpc,
                                         int predictor,
                                         int Colors,
                                         int BitsPerComponent,
                                         int Columns) {
  m_SrcBuf = src_buf;
  m_SrcSize = src_size;
  m_OutputWidth = m_OrigWidth = width;
  m_OutputHeight = m_OrigHeight = height;
  m_nComps = nComps;
  m_bpc = bpc;
  m_Pitch = (static_cast<uint32_t>(width) * nComps * bpc + 7) / 8;
  m_pScanline = FX_Alloc(uint8_t, m_Pitch);
  m_Predictor = 0;
  if (predictor) {
    if (predictor >= 10) {
      m_Predictor = 2;
    } else if (predictor == 2) {
      m_Predictor = 1;
    }
    if (m_Predictor) {
      if (BitsPerComponent * Colors * Columns == 0) {
        BitsPerComponent = m_bpc;
        Colors = m_nComps;
        Columns = m_OrigWidth;
      }
      m_Colors = Colors;
      m_BitsPerComponent = BitsPerComponent;
      m_Columns = Columns;
      m_PredictPitch =
          (static_cast<uint32_t>(m_BitsPerComponent) * m_Colors * m_Columns +
           7) /
          8;
      m_pLastLine = FX_Alloc(uint8_t, m_PredictPitch);
      m_pPredictRaw = FX_Alloc(uint8_t, m_PredictPitch + 1);
      m_pPredictBuffer = FX_Alloc(uint8_t, m_PredictPitch);
    }
  }
}
bool CCodec_FlateScanlineDecoder::v_Rewind() {
  if (m_pFlate) {
    FPDFAPI_FlateEnd(m_pFlate);
  }
  m_pFlate = FPDFAPI_FlateInit(my_alloc_func, my_free_func);
  if (!m_pFlate) {
    return false;
  }
  FPDFAPI_FlateInput(m_pFlate, m_SrcBuf, m_SrcSize);
  m_LeftOver = 0;
  return true;
}
uint8_t* CCodec_FlateScanlineDecoder::v_GetNextLine() {
  if (m_Predictor) {
    if (m_Pitch == m_PredictPitch) {
      if (m_Predictor == 2) {
        FPDFAPI_FlateOutput(m_pFlate, m_pPredictRaw, m_PredictPitch + 1);
        PNG_PredictLine(m_pScanline, m_pPredictRaw, m_pLastLine,
                        m_BitsPerComponent, m_Colors, m_Columns);
        FXSYS_memcpy(m_pLastLine, m_pScanline, m_PredictPitch);
      } else {
        FPDFAPI_FlateOutput(m_pFlate, m_pScanline, m_Pitch);
        TIFF_PredictLine(m_pScanline, m_PredictPitch, m_bpc, m_nComps,
                         m_OutputWidth);
      }
    } else {
      size_t bytes_to_go = m_Pitch;
      size_t read_leftover =
          m_LeftOver > bytes_to_go ? bytes_to_go : m_LeftOver;
      if (read_leftover) {
        FXSYS_memcpy(m_pScanline,
                     m_pPredictBuffer + m_PredictPitch - m_LeftOver,
                     read_leftover);
        m_LeftOver -= read_leftover;
        bytes_to_go -= read_leftover;
      }
      while (bytes_to_go) {
        if (m_Predictor == 2) {
          FPDFAPI_FlateOutput(m_pFlate, m_pPredictRaw, m_PredictPitch + 1);
          PNG_PredictLine(m_pPredictBuffer, m_pPredictRaw, m_pLastLine,
                          m_BitsPerComponent, m_Colors, m_Columns);
          FXSYS_memcpy(m_pLastLine, m_pPredictBuffer, m_PredictPitch);
        } else {
          FPDFAPI_FlateOutput(m_pFlate, m_pPredictBuffer, m_PredictPitch);
          TIFF_PredictLine(m_pPredictBuffer, m_PredictPitch, m_BitsPerComponent,
                           m_Colors, m_Columns);
        }
        size_t read_bytes =
            m_PredictPitch > bytes_to_go ? bytes_to_go : m_PredictPitch;
        FXSYS_memcpy(m_pScanline + m_Pitch - bytes_to_go, m_pPredictBuffer,
                     read_bytes);
        m_LeftOver += m_PredictPitch - read_bytes;
        bytes_to_go -= read_bytes;
      }
    }
  } else {
    FPDFAPI_FlateOutput(m_pFlate, m_pScanline, m_Pitch);
  }
  return m_pScanline;
}
uint32_t CCodec_FlateScanlineDecoder::GetSrcOffset() {
  return FPDFAPI_FlateGetTotalIn(m_pFlate);
}

CCodec_ScanlineDecoder* CCodec_FlateModule::CreateDecoder(
    const uint8_t* src_buf,
    uint32_t src_size,
    int width,
    int height,
    int nComps,
    int bpc,
    int predictor,
    int Colors,
    int BitsPerComponent,
    int Columns) {
  CCodec_FlateScanlineDecoder* pDecoder = new CCodec_FlateScanlineDecoder;
  pDecoder->Create(src_buf, src_size, width, height, nComps, bpc, predictor,
                   Colors, BitsPerComponent, Columns);
  return pDecoder;
}
uint32_t CCodec_FlateModule::FlateOrLZWDecode(bool bLZW,
                                              const uint8_t* src_buf,
                                              uint32_t src_size,
                                              bool bEarlyChange,
                                              int predictor,
                                              int Colors,
                                              int BitsPerComponent,
                                              int Columns,
                                              uint32_t estimated_size,
                                              uint8_t*& dest_buf,
                                              uint32_t& dest_size) {
  dest_buf = nullptr;
  uint32_t offset = 0;
  int predictor_type = 0;
  if (predictor) {
    if (predictor >= 10) {
      predictor_type = 2;
    } else if (predictor == 2) {
      predictor_type = 1;
    }
  }
  if (bLZW) {
    {
      std::unique_ptr<CLZWDecoder> decoder(new CLZWDecoder);
      dest_size = (uint32_t)-1;
      offset = src_size;
      int err =
          decoder->Decode(nullptr, dest_size, src_buf, offset, bEarlyChange);
      if (err || dest_size == 0 || dest_size + 1 < dest_size) {
        return FX_INVALID_OFFSET;
      }
    }
    {
      std::unique_ptr<CLZWDecoder> decoder(new CLZWDecoder);
      dest_buf = FX_Alloc(uint8_t, dest_size + 1);
      dest_buf[dest_size] = '\0';
      decoder->Decode(dest_buf, dest_size, src_buf, offset, bEarlyChange);
    }
  } else {
    FlateUncompress(src_buf, src_size, estimated_size, dest_buf, dest_size,
                    offset);
  }
  if (predictor_type == 0) {
    return offset;
  }
  bool ret = true;
  if (predictor_type == 2) {
    ret = PNG_Predictor(dest_buf, dest_size, Colors, BitsPerComponent, Columns);
  } else if (predictor_type == 1) {
    ret =
        TIFF_Predictor(dest_buf, dest_size, Colors, BitsPerComponent, Columns);
  }
  return ret ? offset : FX_INVALID_OFFSET;
}

bool CCodec_FlateModule::Encode(const uint8_t* src_buf,
                                uint32_t src_size,
                                uint8_t** dest_buf,
                                uint32_t* dest_size) {
  *dest_size = src_size + src_size / 1000 + 12;
  *dest_buf = FX_Alloc(uint8_t, *dest_size);
  unsigned long temp_size = *dest_size;
  if (!FPDFAPI_FlateCompress(*dest_buf, &temp_size, src_buf, src_size))
    return false;

  *dest_size = (uint32_t)temp_size;
  return true;
}

bool CCodec_FlateModule::PngEncode(const uint8_t* src_buf,
                                   uint32_t src_size,
                                   uint8_t** dest_buf,
                                   uint32_t* dest_size) {
  uint8_t* pSrcBuf = FX_Alloc(uint8_t, src_size);
  FXSYS_memcpy(pSrcBuf, src_buf, src_size);
  PNG_PredictorEncode(&pSrcBuf, &src_size);
  bool ret = Encode(pSrcBuf, src_size, dest_buf, dest_size);
  FX_Free(pSrcBuf);
  return ret;
}