/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.apache.commons.compress.compressors.xz;
import java.io.IOException;
import java.io.InputStream;
import org.tukaani.xz.XZ;
import org.tukaani.xz.SingleXZInputStream;
import org.tukaani.xz.XZInputStream;
import org.apache.commons.compress.compressors.CompressorInputStream;
/**
* XZ decompressor.
* @since Commons Compress 1.4
*/
public class XZCompressorInputStream extends CompressorInputStream {
private final InputStream in;
/**
* Checks if the signature matches what is expected for a .xz file.
*
* @param signature the bytes to check
* @param length the number of bytes to check
* @return true if signature matches the .xz magic bytes, false otherwise
*/
public static boolean matches(byte[] signature, int length) {
if (length < XZ.HEADER_MAGIC.length) {
return false;
}
for (int i = 0; i < XZ.HEADER_MAGIC.length; ++i) {
if (signature[i] != XZ.HEADER_MAGIC[i]) {
return false;
}
}
return true;
}
/**
* Creates a new input stream that decompresses XZ-compressed data
* from the specified input stream. This doesn't support
* concatenated .xz files.
*
* @param inputStream where to read the compressed data
*
* @throws IOException if the input is not in the .xz format,
* the input is corrupt or truncated, the .xz
* headers specify options that are not supported
* by this implementation, or the underlying
* <code>inputStream</code> throws an exception
*/
public XZCompressorInputStream(InputStream inputStream)
throws IOException {
this(inputStream, false);
}
/**
* Creates a new input stream that decompresses XZ-compressed data
* from the specified input stream.
*
* @param inputStream where to read the compressed data
* @param decompressConcatenated
* if true, decompress until the end of the
* input; if false, stop after the first .xz
* stream and leave the input position to point
* to the next byte after the .xz stream
*
* @throws IOException if the input is not in the .xz format,
* the input is corrupt or truncated, the .xz
* headers specify options that are not supported
* by this implementation, or the underlying
* <code>inputStream</code> throws an exception
*/
public XZCompressorInputStream(InputStream inputStream,
boolean decompressConcatenated)
throws IOException {
if (decompressConcatenated) {
in = new XZInputStream(inputStream);
} else {
in = new SingleXZInputStream(inputStream);
}
}
/** {@inheritDoc} */
@Override
public int read() throws IOException {
int ret = in.read();
count(ret == -1 ? -1 : 1);
return ret;
}
/** {@inheritDoc} */
@Override
public int read(byte[] buf, int off, int len) throws IOException {
int ret = in.read(buf, off, len);
count(ret);
return ret;
}
/** {@inheritDoc} */
@Override
public long skip(long n) throws IOException {
return in.skip(n);
}
/** {@inheritDoc} */
@Override
public int available() throws IOException {
return in.available();
}
/** {@inheritDoc} */
@Override
public void close() throws IOException {
in.close();
}
}