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;
023
024import org.apache.commons.compress.compressors.CompressorOutputStream;
025import org.tukaani.xz.LZMA2Options;
026import org.tukaani.xz.XZOutputStream;
027
028/**
029 * XZ compressor.
030 *
031 * <em>Calling flush()</em>
032 * <p>
033 * Calling {@link #flush()} flushes the encoder and calls {@code outputStream.flush()}. All buffered pending data will then be decompressible from the output
034 * stream. Calling this function very often may increase the compressed file size a lot.
035 * </p>
036 *
037 * @since 1.4
038 */
039public class XZCompressorOutputStream extends CompressorOutputStream<XZOutputStream> {
040
041    /**
042     * Creates a new XZ compressor using the default LZMA2 options. This is equivalent to {@code XZCompressorOutputStream(outputStream, 6)}.
043     *
044     * @param outputStream the stream to wrap
045     * @throws IOException on error
046     */
047    @SuppressWarnings("resource") // Caller closes
048    public XZCompressorOutputStream(final OutputStream outputStream) throws IOException {
049        super(new XZOutputStream(outputStream, new LZMA2Options()));
050    }
051
052    /**
053     * Creates a new XZ compressor using the specified LZMA2 preset level.
054     * <p>
055     * The presets 0-3 are fast presets with medium compression. The presets 4-6 are fairly slow presets with high compression. The default preset is 6.
056     * <p>
057     * The presets 7-9 are like the preset 6 but use bigger dictionaries and have higher compressor and decompressor memory requirements. Unless the
058     * uncompressed size of the file exceeds 8&nbsp;MiB, 16&nbsp;MiB, or 32&nbsp;MiB, it is waste of memory to use the presets 7, 8, or 9, respectively.
059     *
060     * @param outputStream the stream to wrap
061     * @param preset       the preset
062     * @throws IOException on error
063     */
064    @SuppressWarnings("resource") // Caller closes
065    public XZCompressorOutputStream(final OutputStream outputStream, final int preset) throws IOException {
066        super(new XZOutputStream(outputStream, new LZMA2Options(preset)));
067    }
068
069    /**
070     * Finishes compression without closing the underlying stream. No more data can be written to this stream after finishing.
071     *
072     * @throws IOException on error
073     */
074    @SuppressWarnings("resource") // instance variable access
075    public void finish() throws IOException {
076        out().finish();
077    }
078
079    @Override
080    public void write(final byte[] buf, final int off, final int len) throws IOException {
081        out.write(buf, off, len);
082    }
083
084}