1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19 package org.apache.commons.compress.compressors.xz;
20
21 import java.io.IOException;
22 import java.io.OutputStream;
23
24 import org.apache.commons.compress.compressors.CompressorOutputStream;
25 import org.tukaani.xz.LZMA2Options;
26 import org.tukaani.xz.XZOutputStream;
27
28 /**
29 * XZ compressor.
30 *
31 * <em>Calling flush()</em>
32 * <p>
33 * Calling {@link #flush()} flushes the encoder and calls {@code outputStream.flush()}. All buffered pending data will then be decompressible from the output
34 * stream. Calling this function very often may increase the compressed file size a lot.
35 * </p>
36 *
37 * @since 1.4
38 */
39 public class XZCompressorOutputStream extends CompressorOutputStream<XZOutputStream> {
40
41 /**
42 * Creates a new XZ compressor using the default LZMA2 options. This is equivalent to {@code XZCompressorOutputStream(outputStream, 6)}.
43 *
44 * @param outputStream the stream to wrap
45 * @throws IOException on error
46 */
47 @SuppressWarnings("resource") // Caller closes
48 public XZCompressorOutputStream(final OutputStream outputStream) throws IOException {
49 super(new XZOutputStream(outputStream, new LZMA2Options()));
50 }
51
52 /**
53 * Creates a new XZ compressor using the specified LZMA2 preset level.
54 * <p>
55 * 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.
56 * <p>
57 * The presets 7-9 are like the preset 6 but use bigger dictionaries and have higher compressor and decompressor memory requirements. Unless the
58 * uncompressed size of the file exceeds 8 MiB, 16 MiB, or 32 MiB, it is waste of memory to use the presets 7, 8, or 9, respectively.
59 *
60 * @param outputStream the stream to wrap
61 * @param preset the preset
62 * @throws IOException on error
63 */
64 @SuppressWarnings("resource") // Caller closes
65 public XZCompressorOutputStream(final OutputStream outputStream, final int preset) throws IOException {
66 super(new XZOutputStream(outputStream, new LZMA2Options(preset)));
67 }
68
69 /**
70 * Finishes compression without closing the underlying stream. No more data can be written to this stream after finishing.
71 *
72 * @throws IOException on error
73 */
74 @SuppressWarnings("resource") // instance variable access
75 public void finish() throws IOException {
76 out().finish();
77 }
78
79 @Override
80 public void write(final byte[] buf, final int off, final int len) throws IOException {
81 out.write(buf, off, len);
82 }
83
84 }