001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 * http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing,
013 * software distributed under the License is distributed on an
014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
015 * KIND, either express or implied.  See the License for the
016 * specific language governing permissions and limitations
017 * under the License.
018 */
019package org.apache.commons.compress.compressors.xz;
020
021import java.io.IOException;
022import java.io.OutputStream;
023import org.tukaani.xz.LZMA2Options;
024import org.tukaani.xz.XZOutputStream;
025
026import org.apache.commons.compress.compressors.CompressorOutputStream;
027
028/**
029 * XZ compressor.
030 * @since 1.4
031 */
032public class XZCompressorOutputStream extends CompressorOutputStream {
033    private final XZOutputStream out;
034
035    /**
036     * Creates a new XZ compressor using the default LZMA2 options.
037     * This is equivalent to <code>XZCompressorOutputStream(6)</code>.
038     */
039    public XZCompressorOutputStream(OutputStream outputStream)
040            throws IOException {
041        out = new XZOutputStream(outputStream, new LZMA2Options());
042    }
043
044    /**
045     * Creates a new XZ compressor using the specified LZMA2 preset level.
046     * <p>
047     * The presets 0-3 are fast presets with medium compression.
048     * The presets 4-6 are fairly slow presets with high compression.
049     * The default preset is 6.
050     * <p>
051     * The presets 7-9 are like the preset 6 but use bigger dictionaries
052     * and have higher compressor and decompressor memory requirements.
053     * Unless the uncompressed size of the file exceeds 8&nbsp;MiB,
054     * 16&nbsp;MiB, or 32&nbsp;MiB, it is waste of memory to use the
055     * presets 7, 8, or 9, respectively.
056     */
057    public XZCompressorOutputStream(OutputStream outputStream, int preset)
058            throws IOException {
059        out = new XZOutputStream(outputStream, new LZMA2Options(preset));
060    }
061
062    @Override
063    public void write(int b) throws IOException {
064        out.write(b);
065    }
066
067    @Override
068    public void write(byte[] buf, int off, int len) throws IOException {
069        out.write(buf, off, len);
070    }
071
072    /**
073     * Flushes the encoder and calls <code>outputStream.flush()</code>.
074     * All buffered pending data will then be decompressible from
075     * the output stream. Calling this function very often may increase
076     * the compressed file size a lot.
077     */
078    @Override
079    public void flush() throws IOException {
080        out.flush();
081    }
082
083    /**
084     * Finishes compression without closing the underlying stream.
085     * No more data can be written to this stream after finishing.
086     */
087    public void finish() throws IOException {
088        out.finish();
089    }
090
091    @Override
092    public void close() throws IOException {
093        out.close();
094    }
095}