misc/libphysfs/lzma/Java/SevenZip/Compression/LZ/InWindow.java
changeset 12218 bb5522e88ab2
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/misc/libphysfs/lzma/Java/SevenZip/Compression/LZ/InWindow.java	Mon Apr 10 12:06:43 2017 -0400
@@ -0,0 +1,131 @@
+// LZ.InWindow
+
+package SevenZip.Compression.LZ;
+
+import java.io.IOException;
+
+public class InWindow
+{
+	public byte[] _bufferBase; // pointer to buffer with data
+	java.io.InputStream _stream;
+	int _posLimit;  // offset (from _buffer) of first byte when new block reading must be done
+	boolean _streamEndWasReached; // if (true) then _streamPos shows real end of stream
+	
+	int _pointerToLastSafePosition;
+	
+	public int _bufferOffset;
+	
+	public int _blockSize;  // Size of Allocated memory block
+	public int _pos;             // offset (from _buffer) of curent byte
+	int _keepSizeBefore;  // how many BYTEs must be kept in buffer before _pos
+	int _keepSizeAfter;   // how many BYTEs must be kept buffer after _pos
+	public int _streamPos;   // offset (from _buffer) of first not read byte from Stream
+	
+	public void MoveBlock()
+	{
+		int offset = _bufferOffset + _pos - _keepSizeBefore;
+		// we need one additional byte, since MovePos moves on 1 byte.
+		if (offset > 0)
+			offset--;
+
+		int numBytes = _bufferOffset + _streamPos - offset;
+		
+		// check negative offset ????
+		for (int i = 0; i < numBytes; i++)
+			_bufferBase[i] = _bufferBase[offset + i];
+		_bufferOffset -= offset;
+	}
+	
+	public void ReadBlock() throws IOException
+	{
+		if (_streamEndWasReached)
+			return;
+		while (true)
+		{
+			int size = (0 - _bufferOffset) + _blockSize - _streamPos;
+			if (size == 0)
+				return;
+			int numReadBytes = _stream.read(_bufferBase, _bufferOffset + _streamPos, size);
+			if (numReadBytes == -1)
+			{
+				_posLimit = _streamPos;
+				int pointerToPostion = _bufferOffset + _posLimit;
+				if (pointerToPostion > _pointerToLastSafePosition)
+					_posLimit = _pointerToLastSafePosition - _bufferOffset;
+				
+				_streamEndWasReached = true;
+				return;
+			}
+			_streamPos += numReadBytes;
+			if (_streamPos >= _pos + _keepSizeAfter)
+				_posLimit = _streamPos - _keepSizeAfter;
+		}
+	}
+	
+	void Free() { _bufferBase = null; }
+	
+	public void Create(int keepSizeBefore, int keepSizeAfter, int keepSizeReserv)
+	{
+		_keepSizeBefore = keepSizeBefore;
+		_keepSizeAfter = keepSizeAfter;
+		int blockSize = keepSizeBefore + keepSizeAfter + keepSizeReserv;
+		if (_bufferBase == null || _blockSize != blockSize)
+		{
+			Free();
+			_blockSize = blockSize;
+			_bufferBase = new byte[_blockSize];
+		}
+		_pointerToLastSafePosition = _blockSize - keepSizeAfter;
+	}
+	
+	public void SetStream(java.io.InputStream stream) { _stream = stream; 	}
+	public void ReleaseStream() { _stream = null; }
+
+	public void Init() throws IOException
+	{
+		_bufferOffset = 0;
+		_pos = 0;
+		_streamPos = 0;
+		_streamEndWasReached = false;
+		ReadBlock();
+	}
+	
+	public void MovePos() throws IOException
+	{
+		_pos++;
+		if (_pos > _posLimit)
+		{
+			int pointerToPostion = _bufferOffset + _pos;
+			if (pointerToPostion > _pointerToLastSafePosition)
+				MoveBlock();
+			ReadBlock();
+		}
+	}
+	
+	public byte GetIndexByte(int index)	{ return _bufferBase[_bufferOffset + _pos + index]; }
+	
+	// index + limit have not to exceed _keepSizeAfter;
+	public int GetMatchLen(int index, int distance, int limit)
+	{
+		if (_streamEndWasReached)
+			if ((_pos + index) + limit > _streamPos)
+				limit = _streamPos - (_pos + index);
+		distance++;
+		// Byte *pby = _buffer + (size_t)_pos + index;
+		int pby = _bufferOffset + _pos + index;
+		
+		int i;
+		for (i = 0; i < limit && _bufferBase[pby + i] == _bufferBase[pby + i - distance]; i++);
+		return i;
+	}
+	
+	public int GetNumAvailableBytes()	{ return _streamPos - _pos; }
+	
+	public void ReduceOffsets(int subValue)
+	{
+		_bufferOffset += subValue;
+		_posLimit -= subValue;
+		_pos -= subValue;
+		_streamPos -= subValue;
+	}
+}