release/src-rt-6.x/linux/linux-2.6/scripts/squashfs/lzma/C/7zip/Compress/LZ/LZInWindow.h

   1 // LZInWindow.h
   2
   3 #ifndef __LZ_IN_WINDOW_H
   4 #define __LZ_IN_WINDOW_H
   5
   6 #include "../../IStream.h"
   7
   8 class CLZInWindow
   9 {
  10   Byte *_bufferBase; // pointer to buffer with data
  11   ISequentialInStream *_stream;
  12   UInt32 _posLimit;  // offset (from _buffer) of first byte when new block reading must be done
  13   bool _streamEndWasReached; // if (true) then _streamPos shows real end of stream
  14   const Byte *_pointerToLastSafePosition;
  15 protected:
  16   Byte  *_buffer;   // Pointer to virtual Buffer begin
  17   UInt32 _blockSize;  // Size of Allocated memory block
  18   UInt32 _pos;             // offset (from _buffer) of curent byte
  19   UInt32 _keepSizeBefore;  // how many BYTEs must be kept in buffer before _pos
  20   UInt32 _keepSizeAfter;   // how many BYTEs must be kept buffer after _pos
  21   UInt32 _keepSizeReserv;  // how many BYTEs must be kept as reserv
  22   UInt32 _streamPos;   // offset (from _buffer) of first not read byte from Stream
  23
  24   virtual void BeforeMoveBlock() {};
  25   virtual void AfterMoveBlock() {};
  26   void MoveBlock();
  27   virtual HRESULT ReadBlock();
  28   void Free();
  29 public:
  30   CLZInWindow(): _bufferBase(0) {}
  31   virtual ~CLZInWindow() { Free(); }
  32
  33   bool Create(UInt32 keepSizeBefore, UInt32 keepSizeAfter,
  34       UInt32 keepSizeReserv = (1<<17));
  35
  36   HRESULT Init(ISequentialInStream *stream);
  37   // void ReleaseStream();
  38
  39   Byte *GetBuffer() const { return _buffer; }
  40
  41   const Byte *GetPointerToCurrentPos() const { return _buffer + _pos; }
  42
  43   HRESULT MovePos()
  44   {
  45     _pos++;
  46     if (_pos > _posLimit)
  47     {
  48       const Byte *pointerToPostion = _buffer + _pos;
  49       if(pointerToPostion > _pointerToLastSafePosition)
  50         MoveBlock();
  51       return ReadBlock();
  52     }
  53     else
  54       return S_OK;
  55   }
  56   Byte GetIndexByte(Int32 index)const
  57     {  return _buffer[(size_t)_pos + index]; }
  58
  59   // index + limit have not to exceed _keepSizeAfter;
  60   UInt32 GetMatchLen(Int32 index, UInt32 distance, UInt32 limit) const
  61   {
  62     if(_streamEndWasReached)
  63       if ((_pos + index) + limit > _streamPos)
  64         limit = _streamPos - (_pos + index);
  65     distance++;
  66     Byte *pby = _buffer + (size_t)_pos + index;
  67     UInt32 i;
  68     for(i = 0; i < limit && pby[i] == pby[(size_t)i - distance]; i++);
  69     return i;
  70   }
  71
  72   UInt32 GetNumAvailableBytes() const { return _streamPos - _pos; }
  73
  74   void ReduceOffsets(Int32 subValue)
  75   {
  76     _buffer += subValue;
  77     _posLimit -= subValue;
  78     _pos -= subValue;
  79     _streamPos -= subValue;
  80   }
  81
  82 };
  83
  84 #endif