OutWindow.java

// LZ.OutWindow
package sevenzip.compression.lz;

import java.io.IOException;


public class OutWindow {

    byte[] _buffer;

    int _pos;

    int _windowSize = 0;

    int _streamPos;

    java.io.OutputStream _stream;


    public void Create(int windowSize) {
        if (_buffer==null||_windowSize!=windowSize) {
            _buffer = new byte[windowSize];
        }
        _windowSize = windowSize;
        _pos = 0;
        _streamPos = 0;
    }


    public void SetStream(java.io.OutputStream stream) throws IOException {
        ReleaseStream();
        _stream = stream;
    }


    public void ReleaseStream() throws IOException {
        Flush();
        _stream = null;
    }


    public void Init(boolean solid) {
        if (!solid) {
            _streamPos = 0;
            _pos = 0;
        }
    }


    public void Flush() throws IOException {
        int size = _pos-_streamPos;
        if (size==0) {
            return;
        }
        _stream.write(_buffer, _streamPos, size);
        if (_pos>=_windowSize) {
            _pos = 0;
        }
        _streamPos = _pos;
    }


    public void CopyBlock(int distance, int len) throws IOException {
        int pos = _pos-distance-1;
        if (pos<0) {
            pos += _windowSize;
        }
        for (; len!=0; len--) {
            if (pos>=_windowSize) {
                pos = 0;
            }
            _buffer[_pos++] = _buffer[pos++];
            if (_pos>=_windowSize) {
                Flush();
            }
        }
    }


    public void PutByte(byte b) throws IOException {
        _buffer[_pos++] = b;
        if (_pos>=_windowSize) {
            Flush();
        }
    }


    public byte GetByte(int distance) {
        int pos = _pos-distance-1;
        if (pos<0) {
            pos += _windowSize;
        }
        return _buffer[pos];
    }

}