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This bundle is the core implementation of the Karaf features support.
/*
* 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.karaf.features.internal.util;
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.zip.CRC32;
public final class ChecksumUtils {
private ChecksumUtils() {
}
/**
* Compute a checksum for the file or directory that consists of the name, length and the last modified date
* for a file and its children in case of a directory
*
* @param is the input stream
* @return a checksum identifying any change
* @throws IOException in case of checksum failure.
*/
public static long checksum(InputStream is) throws IOException {
CRC32 crc = new CRC32();
byte[] buffer = new byte[8192];
int l;
while ((l = is.read(buffer)) > 0) {
crc.update(buffer, 0, l);
}
return crc.getValue();
}
public static class CRCInputStream extends FilterInputStream {
private final CRC32 crc = new CRC32();
public CRCInputStream(InputStream in) {
super(in);
}
public long getCRC() {
return crc.getValue();
}
@Override
public int read() throws IOException {
byte[] b = new byte[1];
int nb = read(b, 0, 1);
return nb == 1 ? b[0] : -1;
}
@Override
public int read(byte[] b, int off, int len) throws IOException {
int nb = super.read(b, off, len);
if (nb > 0) {
crc.update(b, off, nb);
}
return nb;
}
}
}