3.13

7zip/Compress/LZ/LZInWindow.cpp

@@ -0,0 +1,98 @@
+// LZInWindow.cpp
+
+#include "StdAfx.h"
+
+#include "LZInWindow.h"
+#include "../../../Common/MyCom.h"
+
+CLZInWindow::~CLZInWindow()
+{
+  Free();
+}
+
+void CLZInWindow::Free()
+{
+  delete []_bufferBase;
+  _bufferBase = 0;
+}
+
+void CLZInWindow::Create(UINT32 keepSizeBefore, UINT32 keepSizeAfter, UINT32 keepSizeReserv)
+{
+  _keepSizeBefore = keepSizeBefore;
+  _keepSizeAfter = keepSizeAfter;
+  _keepSizeReserv = keepSizeReserv;
+  _blockSize = keepSizeBefore + keepSizeAfter + keepSizeReserv;
+  Free();
+  _bufferBase = new BYTE[_blockSize];
+  _pointerToLastSafePosition = _bufferBase + _blockSize - keepSizeAfter;
+}
+
+
+HRESULT CLZInWindow::Init(ISequentialInStream *stream)
+{
+  _stream = stream;
+  _buffer = _bufferBase;
+  _pos = 0;
+  _streamPos = 0;
+  _streamEndWasReached = false;
+  return ReadBlock();
+}
+
+/*
+void CLZInWindow::ReleaseStream()
+{
+  _stream.Release();
+}
+*/
+
+///////////////////////////////////////////
+// ReadBlock
+
+// In State:
+//   (_buffer + _streamPos) <= (_bufferBase + _blockSize)
+// Out State:
+//   _posLimit <= _blockSize - _keepSizeAfter;
+//   if(_streamEndWasReached == false):
+//     _streamPos >= _pos + _keepSizeAfter
+//     _posLimit = _streamPos - _keepSizeAfter;
+//   else
+//          
+  
+HRESULT CLZInWindow::ReadBlock()
+{
+  if(_streamEndWasReached)
+    return S_OK;
+  while(true)
+  {
+    UINT32 size = (_bufferBase + _blockSize) - (_buffer + _streamPos);
+    if(size == 0)
+      return S_OK;
+    UINT32 numReadBytes;
+    RINOK(_stream->ReadPart(_buffer + _streamPos, size, &numReadBytes));
+    if(numReadBytes == 0)
+    {
+      _posLimit = _streamPos;
+      const BYTE *pointerToPostion = _buffer + _posLimit;
+      if(pointerToPostion > _pointerToLastSafePosition)
+        _posLimit = _pointerToLastSafePosition - _buffer;
+      _streamEndWasReached = true;
+      return S_OK;
+    }
+    _streamPos += numReadBytes;
+    if(_streamPos >= _pos + _keepSizeAfter)
+    {
+      _posLimit = _streamPos - _keepSizeAfter;
+      return S_OK;
+    }
+  }
+}
+
+void CLZInWindow::MoveBlock()
+{
+  BeforeMoveBlock();
+  UINT32 offset = (_buffer + _pos - _keepSizeBefore) - _bufferBase;
+  UINT32 numBytes = (_buffer + _streamPos) -  (_bufferBase + offset);
+  memmove(_bufferBase, _bufferBase + offset, numBytes);
+  _buffer -= offset;
+  AfterMoveBlock();
+}