116 lines
2.3 KiB
C#
116 lines
2.3 KiB
C#
namespace SevenZip.Compression.LZ
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{
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public class OutWindow
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{
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byte[] _buffer = null;
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uint _pos;
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uint _windowSize = 0;
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uint _streamPos;
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uint _writePos;
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internal System.IO.Stream _stream;
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public uint TrainSize = 0;
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public void Create(uint windowSize)
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{
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if (_windowSize != windowSize)
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{
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// System.GC.Collect();
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_buffer = new byte[windowSize];
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}
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_windowSize = windowSize;
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_pos = 0;
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_streamPos = 0;
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_writePos = 0;
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}
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public void Init(System.IO.Stream stream, bool solid)
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{
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ReleaseStream();
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_stream = stream;
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if (!solid)
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{
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_streamPos = 0;
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_writePos = 0;
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_pos = 0;
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TrainSize = 0;
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}
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}
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public bool Train(System.IO.Stream stream)
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{
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long len = stream.Length;
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uint size = (len < _windowSize) ? (uint)len : _windowSize;
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TrainSize = size;
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stream.Position = len - size;
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_streamPos = _pos = _writePos = 0;
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while (size > 0)
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{
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uint curSize = _windowSize - _pos;
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if (size < curSize)
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curSize = size;
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int numReadBytes = stream.Read(_buffer, (int)_pos, (int)curSize);
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if (numReadBytes == 0)
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return false;
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size -= (uint)numReadBytes;
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_pos += (uint)numReadBytes;
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_streamPos += (uint)numReadBytes;
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_writePos += (uint)numReadBytes;
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if (_pos == _windowSize)
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_streamPos = _pos = _writePos = 0;
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}
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return true;
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}
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public void ReleaseStream()
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{
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Flush();
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_stream = null;
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}
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public void Flush(bool writeOnly = false, int avoidNewestCount = 0)
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{
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int size = (int)(_pos - _writePos) - avoidNewestCount;
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if (size <= 0)
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return;
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_stream.Write(_buffer, (int)_writePos, (int)size);
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_writePos += (uint)size;
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if (!writeOnly) {
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if (_pos >= _windowSize)
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_pos = 0;
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_streamPos = _pos;
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}
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}
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public void CopyBlock(uint distance, uint len)
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{
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uint pos = _pos - distance - 1;
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if (pos >= _windowSize)
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pos += _windowSize;
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for (; len > 0; len--)
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{
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if (pos >= _windowSize)
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pos = 0;
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_buffer[_pos++] = _buffer[pos++];
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if (_pos >= _windowSize)
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Flush();
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}
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}
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public void PutByte(byte b)
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{
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_buffer[_pos++] = b;
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if (_pos >= _windowSize)
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Flush();
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}
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public byte GetByte(uint distance)
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{
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uint pos = _pos - distance - 1;
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if (pos >= _windowSize)
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pos += _windowSize;
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return _buffer[pos];
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}
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}
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} |