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.lzma;
020
021import java.io.IOException;
022import java.io.InputStream;
023
024import org.apache.commons.compress.MemoryLimitException;
025import org.tukaani.xz.LZMAInputStream;
026
027import org.apache.commons.compress.compressors.CompressorInputStream;
028import org.apache.commons.compress.utils.CountingInputStream;
029import org.apache.commons.compress.utils.IOUtils;
030import org.apache.commons.compress.utils.InputStreamStatistics;
031
032/**
033 * LZMA decompressor.
034 * @since 1.6
035 */
036public class LZMACompressorInputStream extends CompressorInputStream
037    implements InputStreamStatistics {
038
039    private final CountingInputStream countingStream;
040    private final InputStream in;
041
042    /**
043     * Creates a new input stream that decompresses LZMA-compressed data
044     * from the specified input stream.
045     *
046     * @param       inputStream where to read the compressed data
047     *
048     * @throws      IOException if the input is not in the .lzma format,
049     *                          the input is corrupt or truncated, the .lzma
050     *                          headers specify sizes that are not supported
051     *                          by this implementation, or the underlying
052     *                          <code>inputStream</code> throws an exception
053     */
054    public LZMACompressorInputStream(final InputStream inputStream)
055            throws IOException {
056        in = new LZMAInputStream(countingStream = new CountingInputStream(inputStream), -1);
057    }
058
059    /**
060     * Creates a new input stream that decompresses LZMA-compressed data
061     * from the specified input stream.
062     *
063     * @param       inputStream where to read the compressed data
064     *
065     * @param       memoryLimitInKb calculated memory use threshold.  Throws MemoryLimitException
066     *                            if calculate memory use is above this threshold
067     *
068     * @throws      IOException if the input is not in the .lzma format,
069     *                          the input is corrupt or truncated, the .lzma
070     *                          headers specify sizes that are not supported
071     *                          by this implementation, or the underlying
072     *                          <code>inputStream</code> throws an exception
073     *
074     * @since 1.14
075     */
076    public LZMACompressorInputStream(final InputStream inputStream, int memoryLimitInKb)
077            throws IOException {
078        try {
079            in = new LZMAInputStream(countingStream = new CountingInputStream(inputStream), memoryLimitInKb);
080        } catch (org.tukaani.xz.MemoryLimitException e) {
081            //convert to commons-compress exception
082            throw new MemoryLimitException(e.getMemoryNeeded(), e.getMemoryLimit(), e);
083        }
084    }
085
086    /** {@inheritDoc} */
087    @Override
088    public int read() throws IOException {
089        final int ret = in.read();
090        count(ret == -1 ? 0 : 1);
091        return ret;
092    }
093
094    /** {@inheritDoc} */
095    @Override
096    public int read(final byte[] buf, final int off, final int len) throws IOException {
097        final int ret = in.read(buf, off, len);
098        count(ret);
099        return ret;
100    }
101
102    /** {@inheritDoc} */
103    @Override
104    public long skip(final long n) throws IOException {
105        return IOUtils.skip(in, n);
106    }
107
108    /** {@inheritDoc} */
109    @Override
110    public int available() throws IOException {
111        return in.available();
112    }
113
114    /** {@inheritDoc} */
115    @Override
116    public void close() throws IOException {
117        in.close();
118    }
119
120    /**
121     * @since 1.17
122     */
123    @Override
124    public long getCompressedCount() {
125        return countingStream.getBytesRead();
126    }
127
128    /**
129     * Checks if the signature matches what is expected for an lzma file.
130     *
131     * @param signature
132     *            the bytes to check
133     * @param length
134     *            the number of bytes to check
135     * @return true, if this stream is an lzma  compressed stream, false otherwise
136     *
137     * @since 1.10
138     */
139    public static boolean matches(final byte[] signature, final int length) {
140        return signature != null && length >= 3 &&
141                signature[0] == 0x5d && signature[1] == 0 &&
142                signature[2] == 0;
143    }
144}