de.schlichtherle.io.archive.zip.CheckedZipInputArchive Maven / Gradle / Ivy
/*
* Copyright (C) 2009-2010 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.io.archive.zip;
import de.schlichtherle.io.archive.spi.ArchiveEntry;
import de.schlichtherle.io.rof.ReadOnlyFile;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.util.zip.ZipException;
/**
* A {@link ZipInputArchive} which checks the CRC-32 value for all ZIP entries.
* The additional CRC-32 computation makes this class slower than its super
* class.
*
* If there is a mismatch of the CRC-32 values for a ZIP entry in an input
* archive, the {@link java.io.InputStream#close} method of the corresponding
* stream for the archive entry will throw a
* {@link de.schlichtherle.util.zip.CRC32Exception}.
* This exception is then propagated through the stack up to the corresponding
* file operation in the package {@code de.schlichtherle.io} where it is
* either allowed to pass on or is catched and processed accordingly.
* For example, the {@link de.schlichtherle.io.FileInputStream#close()}
* method would allow the {@code CRC32Exception} to pass on to the
* client application, whereas the
* {@link de.schlichtherle.io.File#catTo(OutputStream)} method would simply
* return {@code false}.
* Other than this, the archive entry will be processed normally.
* So if just the CRC-32 value for the entry in the archive file has been
* modified, you can still read its entire contents.
*
* @see ZipInputArchive
* @see CheckedZipDriver
* @author Christian Schlichtherle
* @version $Id: CheckedZipInputArchive.java,v 1.4 2010/08/20 13:09:51 christian_schlichtherle Exp $
* @since TrueZIP 6.1
*/
public class CheckedZipInputArchive extends ZipInputArchive {
public CheckedZipInputArchive(
ReadOnlyFile rof,
String charset,
boolean preambled,
boolean postambled)
throws NullPointerException,
UnsupportedEncodingException,
FileNotFoundException,
ZipException,
IOException {
super(rof, charset, preambled, postambled);
}
/**
* Overridden to read from a checked input stream.
*/
public InputStream getInputStream(
ArchiveEntry entry,
ArchiveEntry dstEntry)
throws IOException {
return super.getInputStream(
entry.getName(), true, !(dstEntry instanceof ZipEntry));
}
}