/**
* This file is part of muCommander, http://www.mucommander.com
* Copyright (C) 2002-2016 Maxence Bernard
*
* muCommander is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* muCommander is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package com.mucommander.commons.file.archive.bzip2;
import com.mucommander.commons.file.*;
import com.mucommander.commons.file.archive.AbstractROArchiveFile;
import com.mucommander.commons.file.archive.ArchiveEntry;
import com.mucommander.commons.file.archive.ArchiveEntryIterator;
import com.mucommander.commons.file.archive.SingleArchiveEntryIterator;
import org.apache.tools.bzip2.CBZip2InputStream;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;
/**
* Bzip2ArchiveFile provides read-only access to archives in the Bzip2 format.
*
* <p>The actual decompression work is performed by the <code>Apache Ant</code> library under the terms of the
* Apache Software License.</p>
*
* @see com.mucommander.commons.file.archive.bzip2.Bzip2FormatProvider
* @author Maxence Bernard
*/
public class Bzip2ArchiveFile extends AbstractROArchiveFile {
private static final Logger LOGGER = LoggerFactory.getLogger(Bzip2ArchiveFile.class);
/**
* Creates a BzipArchiveFile on top of the given file.
*
* @param file the underlying file to wrap this archive file around
*/
public Bzip2ArchiveFile(AbstractFile file) {
super(file);
}
////////////////////////////////////////
// AbstractArchiveFile implementation //
////////////////////////////////////////
@Override
public ArchiveEntryIterator getEntryIterator() throws IOException {
String extension = getCustomExtension() != null ? getCustomExtension() : getExtension();
String name = getName();
if(extension!=null) {
// Remove the 'bz2' or 'tbz2' extension from the entry's name
switch(extension.toLowerCase()) {
case "tbz2":
name = name.substring(0, name.length()-4)+"tar";
break;
case "bz2":
name = name.substring(0, name.length()-4);
break;
default:
}
}
return new SingleArchiveEntryIterator(new ArchiveEntry("/"+name, false, getDate(), -1, true));
}
@Override
public InputStream getEntryInputStream(ArchiveEntry entry, ArchiveEntryIterator entryIterator) throws IOException {
try {
InputStream in = getInputStream();
// Skips the 2 magic bytes 'BZ', as required by CBZip2InputStream. Quoted from CBZip2InputStream's Javadoc:
// "Although BZip2 headers are marked with the magic 'Bz'. this constructor expects the next byte in the
// stream to be the first one after the magic. Thus callers have to skip the first two bytes. Otherwise
// this constructor will throw an exception."
// Note: the return value of read() is unchecked. In the unlikely event that EOF is reached in the first
// 2 bytes, CBZip2InputStream will throw an IOException.
in.read();
in.read();
// Quoted from CBZip2InputStream's Javadoc:
// "CBZip2InputStream reads bytes from the compressed source stream via the single byte {@link java.io.InputStream#read()
// read()} method exclusively. Thus you should consider to use a buffered source stream."
return new CBZip2InputStream(new BufferedInputStream(in));
}
catch(Exception e) {
// CBZip2InputStream is known to throw NullPointerException if file is not properly Bzip2-encoded
// so we need to catch those and throw them as IOException
LOGGER.info("Exception caught while creating CBZip2InputStream, throwing IOException", e);
throw new IOException();
}
}
}