1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/src/win32/7zip/7z/CPP/7zip/Compress/BitlDecoder.h	Sat Mar 03 10:31:27 2012 -0600
     1.3 @@ -0,0 +1,125 @@
     1.4 +// BitlDecoder.h -- the Least Significant Bit of byte is First
     1.5 +
     1.6 +#ifndef __BITL_DECODER_H
     1.7 +#define __BITL_DECODER_H
     1.8 +
     1.9 +#include "../IStream.h"
    1.10 +
    1.11 +namespace NBitl {
    1.12 +
    1.13 +const int kNumBigValueBits = 8 * 4;
    1.14 +
    1.15 +const int kNumValueBytes = 3;
    1.16 +const int kNumValueBits = 8  * kNumValueBytes;
    1.17 +
    1.18 +const UInt32 kMask = (1 << kNumValueBits) - 1;
    1.19 +
    1.20 +extern Byte kInvertTable[256];
    1.21 +
    1.22 +template<class TInByte>
    1.23 +class CBaseDecoder
    1.24 +{
    1.25 +protected:
    1.26 +  int m_BitPos;
    1.27 +  UInt32 m_Value;
    1.28 +  TInByte m_Stream;
    1.29 +public:
    1.30 +  UInt32 NumExtraBytes;
    1.31 +  bool Create(UInt32 bufferSize) { return m_Stream.Create(bufferSize); }
    1.32 +  void SetStream(ISequentialInStream *inStream) { m_Stream.SetStream(inStream); }
    1.33 +  void ReleaseStream() { m_Stream.ReleaseStream(); }
    1.34 +  void Init()
    1.35 +  {
    1.36 +    m_Stream.Init();
    1.37 +    m_BitPos = kNumBigValueBits;
    1.38 +    m_Value = 0;
    1.39 +    NumExtraBytes = 0;
    1.40 +  }
    1.41 +  UInt64 GetProcessedSize() const
    1.42 +    { return m_Stream.GetProcessedSize() - (kNumBigValueBits - m_BitPos) / 8; }
    1.43 +  UInt64 GetProcessedBitsSize() const
    1.44 +    { return (m_Stream.GetProcessedSize() << 3) - (kNumBigValueBits - m_BitPos); }
    1.45 +  int GetBitPosition() const { return (m_BitPos & 7); }
    1.46 +
    1.47 +  void Normalize()
    1.48 +  {
    1.49 +    for (;m_BitPos >= 8; m_BitPos -= 8)
    1.50 +    {
    1.51 +      Byte b = 0;
    1.52 +      if (!m_Stream.ReadByte(b))
    1.53 +      {
    1.54 +        b = 0xFF; // check it
    1.55 +        NumExtraBytes++;
    1.56 +      }
    1.57 +      m_Value = (b << (kNumBigValueBits - m_BitPos)) | m_Value;
    1.58 +    }
    1.59 +  }
    1.60 +  
    1.61 +  UInt32 ReadBits(int numBits)
    1.62 +  {
    1.63 +    Normalize();
    1.64 +    UInt32 res = m_Value & ((1 << numBits) - 1);
    1.65 +    m_BitPos += numBits;
    1.66 +    m_Value >>= numBits;
    1.67 +    return res;
    1.68 +  }
    1.69 +
    1.70 +  bool ExtraBitsWereRead() const
    1.71 +  {
    1.72 +    if (NumExtraBytes == 0)
    1.73 +      return false;
    1.74 +    return ((UInt32)(kNumBigValueBits - m_BitPos) < (NumExtraBytes << 3));
    1.75 +  }
    1.76 +};
    1.77 +
    1.78 +template<class TInByte>
    1.79 +class CDecoder: public CBaseDecoder<TInByte>
    1.80 +{
    1.81 +  UInt32 m_NormalValue;
    1.82 +
    1.83 +public:
    1.84 +  void Init()
    1.85 +  {
    1.86 +    CBaseDecoder<TInByte>::Init();
    1.87 +    m_NormalValue = 0;
    1.88 +  }
    1.89 +
    1.90 +  void Normalize()
    1.91 +  {
    1.92 +    for (; this->m_BitPos >= 8; this->m_BitPos -= 8)
    1.93 +    {
    1.94 +      Byte b = 0;
    1.95 +      if (!this->m_Stream.ReadByte(b))
    1.96 +      {
    1.97 +        b = 0xFF; // check it
    1.98 +        this->NumExtraBytes++;
    1.99 +      }
   1.100 +      m_NormalValue = (b << (kNumBigValueBits - this->m_BitPos)) | m_NormalValue;
   1.101 +      this->m_Value = (this->m_Value << 8) | kInvertTable[b];
   1.102 +    }
   1.103 +  }
   1.104 +  
   1.105 +  UInt32 GetValue(int numBits)
   1.106 +  {
   1.107 +    Normalize();
   1.108 +    return ((this->m_Value >> (8 - this->m_BitPos)) & kMask) >> (kNumValueBits - numBits);
   1.109 +  }
   1.110 +
   1.111 +  void MovePos(int numBits)
   1.112 +  {
   1.113 +    this->m_BitPos += numBits;
   1.114 +    m_NormalValue >>= numBits;
   1.115 +  }
   1.116 +  
   1.117 +  UInt32 ReadBits(int numBits)
   1.118 +  {
   1.119 +    Normalize();
   1.120 +    UInt32 res = m_NormalValue & ( (1 << numBits) - 1);
   1.121 +    MovePos(numBits);
   1.122 +    return res;
   1.123 +  }
   1.124 +};
   1.125 +
   1.126 +}
   1.127 +
   1.128 +#endif