summaryrefslogtreecommitdiff
path: root/Build/source/libs/poppler/poppler-src/poppler/JArithmeticDecoder.h
blob: cb8f481f9b4a5145016b2a83c8e163e21b0d14c7 (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
//========================================================================
//
// JArithmeticDecoder.h
//
// Arithmetic decoder used by the JBIG2 and JPEG2000 decoders.
//
// Copyright 2002-2004 Glyph & Cog, LLC
//
//========================================================================

//========================================================================
//
// Modified under the Poppler project - http://poppler.freedesktop.org
//
// All changes made under the Poppler project to this file are licensed
// under GPL version 2 or later
//
// Copyright (C) 2018 Albert Astals Cid <aacid@kde.org>
//
// To see a description of the changes please see the Changelog file that
// came with your tarball or type make ChangeLog if you are building from git
//
//========================================================================

#ifndef JARITHMETICDECODER_H
#define JARITHMETICDECODER_H

#ifdef USE_GCC_PRAGMAS
#pragma interface
#endif

#include "goo/gtypes.h"

class Stream;

//------------------------------------------------------------------------
// JArithmeticDecoderStats
//------------------------------------------------------------------------

class JArithmeticDecoderStats {
public:

  JArithmeticDecoderStats(int contextSizeA);
  ~JArithmeticDecoderStats();
  JArithmeticDecoderStats(const JArithmeticDecoderStats &) = delete;
  JArithmeticDecoderStats& operator=(const JArithmeticDecoderStats &) = delete;
  JArithmeticDecoderStats *copy();
  void reset();
  int getContextSize() { return contextSize; }
  void copyFrom(JArithmeticDecoderStats *stats);
  void setEntry(Guint cx, int i, int mps);

private:

  Guchar *cxTab;		// cxTab[cx] = (i[cx] << 1) + mps[cx]
  int contextSize;

  friend class JArithmeticDecoder;
};

//------------------------------------------------------------------------
// JArithmeticDecoder
//------------------------------------------------------------------------

class JArithmeticDecoder {
public:

  JArithmeticDecoder();
  ~JArithmeticDecoder();
  JArithmeticDecoder(const JArithmeticDecoder &) = delete;
  JArithmeticDecoder& operator=(const JArithmeticDecoder &) = delete;

  void setStream(Stream *strA)
    { str = strA; dataLen = 0; limitStream = gFalse; }
  void setStream(Stream *strA, int dataLenA)
    { str = strA; dataLen = dataLenA; limitStream = gTrue; }

  // Start decoding on a new stream.  This fills the byte buffers and
  // runs INITDEC.
  void start();

  // Restart decoding on an interrupted stream.  This refills the
  // buffers if needed, but does not run INITDEC.  (This is used in
  // JPEG 2000 streams when codeblock data is split across multiple
  // packets/layers.)
  void restart(int dataLenA);

  // Read any leftover data in the stream.
  void cleanup();

  // Decode one bit.
  int decodeBit(Guint context, JArithmeticDecoderStats *stats);

  // Decode eight bits.
  int decodeByte(Guint context, JArithmeticDecoderStats *stats);

  // Returns false for OOB, otherwise sets *<x> and returns true.
  GBool decodeInt(int *x, JArithmeticDecoderStats *stats);

  Guint decodeIAID(Guint codeLen,
		   JArithmeticDecoderStats *stats);

  void resetByteCounter() { nBytesRead = 0; }
  Guint getByteCounter() { return nBytesRead; }

private:

  Guint readByte();
  int decodeIntBit(JArithmeticDecoderStats *stats);
  void byteIn();

  static Guint qeTab[47];
  static int nmpsTab[47];
  static int nlpsTab[47];
  static int switchTab[47];

  Guint buf0, buf1;
  Guint c, a;
  int ct;

  Guint prev;			// for the integer decoder

  Stream *str;
  Guint nBytesRead;
  int dataLen;
  GBool limitStream;
};

#endif