de.schlichtherle.truezip.fs.archive.tar.TarBZip2Driver Maven / Gradle / Ivy
/*
* Copyright (C) 2005-2011 Schlichtherle IT Services
*
* Licensed 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 de.schlichtherle.truezip.fs.archive.tar;
import de.schlichtherle.truezip.fs.FsConcurrentModel;
import de.schlichtherle.truezip.socket.IOPoolProvider;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import net.jcip.annotations.Immutable;
import org.apache.tools.bzip2.CBZip2InputStream;
import org.apache.tools.bzip2.CBZip2OutputStream;
/**
* An archive driver which builds TAR files compressed with BZIP2.
*
* @author Christian Schlichtherle
* @version $Id$
*/
@Immutable
public class TarBZip2Driver extends TarDriver {
public TarBZip2Driver(IOPoolProvider provider) {
super(provider);
}
public static final int BUFFER_SIZE = 4096;
/**
* Returns the size of the I/O buffer.
*
* The implementation in the class {@link TarBZip2Driver} returns
* {@link #BUFFER_SIZE}.
*
* @return The size of the I/O buffer.
*/
public int getBufferSize() {
return BUFFER_SIZE;
}
/**
* Returns the compression level to use when writing a BZIP2 output stream.
*
* The implementation in the class {@link TarBZip2Driver} returns
* {@link CBZip2OutputStream#MAX_BLOCKSIZE}.
*/
public int getLevel() {
return CBZip2OutputStream.MAX_BLOCKSIZE;
}
/**
* Returns a newly created and verified {@link CBZip2InputStream}.
* This method performs a simple verification by computing the checksum
* for the first record only.
* This method is required because the {@code CBZip2InputStream}
* unfortunately does not do sufficient verification!
*/
@Override
protected TarInputShop newTarInputShop(
final FsConcurrentModel model, final InputStream in)
throws IOException {
// Consume and check the first two magic bytes. This is required for
// the CBZip2InputStream class.
if (in.read() != 'B' || in.read() != 'Z')
throw new IOException("Not a BZIP2 compressed input stream!");
final byte[] magic = new byte[2];
final InputStream vin = TarInputShop.readAhead(in, magic);
if (magic[0] != 'h' || magic[1] < '1' || '9' < magic[1])
throw new IOException("Not a BZIP2 compressed input stream!");
return new TarInputShop(this,
new CBZip2InputStream(
new BufferedInputStream(vin, getBufferSize())));
}
@Override
protected TarOutputShop newTarOutputShop(
final FsConcurrentModel model,
final OutputStream out,
final TarInputShop source)
throws IOException {
// Produce the first two magic bytes. This is required for the
// CBZip2OutputStream class.
out.write(new byte[] { 'B', 'Z' });
return super.newTarOutputShop(
model,
new CBZip2OutputStream(
new BufferedOutputStream(out, getBufferSize()),
getLevel()),
source);
}
}