Upload 2.0.2

[physicsfs] / lzma / CS / 7zip / Compress / LZ / LzInWindow.cs

diff --git a/lzma/CS/7zip/Compress/LZ/LzInWindow.cs b/lzma/CS/7zip/Compress/LZ/LzInWindow.cs
new file mode 100644 (file)
index 0000000..52d23ce
--- /dev/null
+++ b/lzma/CS/7zip/Compress/LZ/LzInWindow.cs
@@ -0,0 +1,132 @@
+// LzInWindow.cs
+
+using System;
+
+namespace SevenZip.Compression.LZ
+{
+       public class InWindow
+       {
+               public Byte[] _bufferBase = null; // pointer to buffer with data
+               System.IO.Stream _stream;
+               UInt32 _posLimit; // offset (from _buffer) of first byte when new block reading must be done
+               bool _streamEndWasReached; // if (true) then _streamPos shows real end of stream
+
+               UInt32 _pointerToLastSafePosition;
+
+               public UInt32 _bufferOffset;
+
+               public UInt32 _blockSize; // Size of Allocated memory block
+               public UInt32 _pos; // offset (from _buffer) of curent byte
+               UInt32 _keepSizeBefore; // how many BYTEs must be kept in buffer before _pos
+               UInt32 _keepSizeAfter; // how many BYTEs must be kept buffer after _pos
+               public UInt32 _streamPos; // offset (from _buffer) of first not read byte from Stream
+
+               public void MoveBlock()
+               {
+                       UInt32 offset = (UInt32)(_bufferOffset) + _pos - _keepSizeBefore;
+                       // we need one additional byte, since MovePos moves on 1 byte.
+                       if (offset > 0)
+                               offset--;
+                       
+                       UInt32 numBytes = (UInt32)(_bufferOffset) + _streamPos - offset;
+
+                       // check negative offset ????
+                       for (UInt32 i = 0; i < numBytes; i++)
+                               _bufferBase[i] = _bufferBase[offset + i];
+                       _bufferOffset -= offset;
+               }
+
+               public virtual void ReadBlock()
+               {
+                       if (_streamEndWasReached)
+                               return;
+                       while (true)
+                       {
+                               int size = (int)((0 - _bufferOffset) + _blockSize - _streamPos);
+                               if (size == 0)
+                                       return;
+                               int numReadBytes = _stream.Read(_bufferBase, (int)(_bufferOffset + _streamPos), size);
+                               if (numReadBytes == 0)
+                               {
+                                       _posLimit = _streamPos;
+                                       UInt32 pointerToPostion = _bufferOffset + _posLimit;
+                                       if (pointerToPostion > _pointerToLastSafePosition)
+                                               _posLimit = (UInt32)(_pointerToLastSafePosition - _bufferOffset);
+
+                                       _streamEndWasReached = true;
+                                       return;
+                               }
+                               _streamPos += (UInt32)numReadBytes;
+                               if (_streamPos >= _pos + _keepSizeAfter)
+                                       _posLimit = _streamPos - _keepSizeAfter;
+                       }
+               }
+
+               void Free() { _bufferBase = null; }
+
+               public void Create(UInt32 keepSizeBefore, UInt32 keepSizeAfter, UInt32 keepSizeReserv)
+               {
+                       _keepSizeBefore = keepSizeBefore;
+                       _keepSizeAfter = keepSizeAfter;
+                       UInt32 blockSize = keepSizeBefore + keepSizeAfter + keepSizeReserv;
+                       if (_bufferBase == null || _blockSize != blockSize)
+                       {
+                               Free();
+                               _blockSize = blockSize;
+                               _bufferBase = new Byte[_blockSize];
+                       }
+                       _pointerToLastSafePosition = _blockSize - keepSizeAfter;
+               }
+
+               public void SetStream(System.IO.Stream stream) { _stream = stream; }
+               public void ReleaseStream() { _stream = null; }
+
+               public void Init()
+               {
+                       _bufferOffset = 0;
+                       _pos = 0;
+                       _streamPos = 0;
+                       _streamEndWasReached = false;
+                       ReadBlock();
+               }
+
+               public void MovePos()
+               {
+                       _pos++;
+                       if (_pos > _posLimit)
+                       {
+                               UInt32 pointerToPostion = _bufferOffset + _pos;
+                               if (pointerToPostion > _pointerToLastSafePosition)
+                                       MoveBlock();
+                               ReadBlock();
+                       }
+               }
+
+               public Byte GetIndexByte(Int32 index) { return _bufferBase[_bufferOffset + _pos + index]; }
+
+               // index + limit have not to exceed _keepSizeAfter;
+               public UInt32 GetMatchLen(Int32 index, UInt32 distance, UInt32 limit)
+               {
+                       if (_streamEndWasReached)
+                               if ((_pos + index) + limit > _streamPos)
+                                       limit = _streamPos - (UInt32)(_pos + index);
+                       distance++;
+                       // Byte *pby = _buffer + (size_t)_pos + index;
+                       UInt32 pby = _bufferOffset + _pos + (UInt32)index;
+
+                       UInt32 i;
+                       for (i = 0; i < limit && _bufferBase[pby + i] == _bufferBase[pby + i - distance]; i++);
+                       return i;
+               }
+
+               public UInt32 GetNumAvailableBytes() { return _streamPos - _pos; }
+
+               public void ReduceOffsets(Int32 subValue)
+               {
+                       _bufferOffset += (UInt32)subValue;
+                       _posLimit -= (UInt32)subValue;
+                       _pos -= (UInt32)subValue;
+                       _streamPos -= (UInt32)subValue;
+               }
+       }
+}