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

   1 // LZInWindow.cpp
   2
   3 #include "StdAfx.h"
   4
   5 #include "LZInWindow.h"
   6 #include "../../../Common/MyCom.h"
   7 #include "../../../Common/Alloc.h"
   8
   9 void CLZInWindow::Free()
  10 {
  11   ::BigFree(_bufferBase);
  12   _bufferBase = 0;
  13 }
  14
  15 bool CLZInWindow::Create(UInt32 keepSizeBefore, UInt32 keepSizeAfter, UInt32 keepSizeReserv)
  16 {
  17   _keepSizeBefore = keepSizeBefore;
  18   _keepSizeAfter = keepSizeAfter;
  19   _keepSizeReserv = keepSizeReserv;
  20   UInt32 blockSize = keepSizeBefore + keepSizeAfter + keepSizeReserv;
  21   if (_bufferBase == 0 || _blockSize != blockSize)
  22   {
  23     Free();
  24     _blockSize = blockSize;
  25     if (_blockSize != 0)
  26       _bufferBase = (Byte *)::BigAlloc(_blockSize);
  27   }
  28   _pointerToLastSafePosition = _bufferBase + _blockSize - keepSizeAfter;
  29   if (_blockSize == 0)
  30     return true;
  31   return (_bufferBase != 0);
  32 }
  33
  34
  35 HRESULT CLZInWindow::Init(ISequentialInStream *stream)
  36 {
  37   _stream = stream;
  38   _buffer = _bufferBase;
  39   _pos = 0;
  40   _streamPos = 0;
  41   _streamEndWasReached = false;
  42   return ReadBlock();
  43 }
  44
  45 /*
  46 void CLZInWindow::ReleaseStream()
  47 {
  48   _stream.Release();
  49 }
  50 */
  51
  52 ///////////////////////////////////////////
  53 // ReadBlock
  54
  55 // In State:
  56 //   (_buffer + _streamPos) <= (_bufferBase + _blockSize)
  57 // Out State:
  58 //   _posLimit <= _blockSize - _keepSizeAfter;
  59 //   if(_streamEndWasReached == false):
  60 //     _streamPos >= _pos + _keepSizeAfter
  61 //     _posLimit = _streamPos - _keepSizeAfter;
  62 //   else
  63 //
  64
  65 HRESULT CLZInWindow::ReadBlock()
  66 {
  67   if(_streamEndWasReached)
  68     return S_OK;
  69   while(true)
  70   {
  71     UInt32 size = UInt32(_bufferBase - _buffer) + _blockSize - _streamPos;
  72     if(size == 0)
  73       return S_OK;
  74     UInt32 numReadBytes;
  75     RINOK(_stream->Read(_buffer + _streamPos, size, &numReadBytes));
  76     if(numReadBytes == 0)
  77     {
  78       _posLimit = _streamPos;
  79       const Byte *pointerToPostion = _buffer + _posLimit;
  80       if(pointerToPostion > _pointerToLastSafePosition)
  81         _posLimit = (UInt32)(_pointerToLastSafePosition - _buffer);
  82       _streamEndWasReached = true;
  83       return S_OK;
  84     }
  85     _streamPos += numReadBytes;
  86     if(_streamPos >= _pos + _keepSizeAfter)
  87     {
  88       _posLimit = _streamPos - _keepSizeAfter;
  89       return S_OK;
  90     }
  91   }
  92 }
  93
  94 void CLZInWindow::MoveBlock()
  95 {
  96   BeforeMoveBlock();
  97   UInt32 offset = UInt32(_buffer - _bufferBase) + _pos - _keepSizeBefore;
  98   UInt32 numBytes = UInt32(_buffer - _bufferBase) + _streamPos -  offset;
  99   memmove(_bufferBase, _bufferBase + offset, numBytes);
 100   _buffer -= offset;
 101   AfterMoveBlock();
 102 }