/*
* 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 java.util.zip;
import java.util.Arrays;
/**
* The Adler-32 class is used to compute the {@code Adler32} checksum from a set
* of data. Compared to {@link CRC32} it trades reliability for speed.
* Refer to RFC 1950 for the specification.
*/
public class Adler32 implements Checksum {
private long adler = 1;
/**
* Returns the {@code Adler32} checksum for all input received.
*
* @return The checksum for this instance.
*/
public long getValue() {
return adler;
}
/**
* Reset this instance to its initial checksum.
*/
public void reset() {
adler = 1;
}
/**
* Update this {@code Adler32} checksum with the single byte provided as
* argument.
*
* @param i
* the byte to update checksum with.
*/
public void update(int i) {
adler = updateByteImpl(i, adler);
}
/**
* Update this {@code Adler32} checksum using the contents of {@code buf}.
*
* @param buf
* bytes to update checksum with.
*/
public void update(byte[] buf) {
update(buf, 0, buf.length);
}
/**
* Update this {@code Adler32} checksum with the contents of {@code buf},
* starting from {@code offset} and reading {@code byteCount} bytes of data.
*/
public void update(byte[] buf, int offset, int byteCount) {
Arrays.checkOffsetAndCount(buf.length, offset, byteCount);
adler = updateImpl(buf, offset, byteCount, adler);
}
private native long updateImpl(byte[] buf, int offset, int byteCount, long adler1);
private native long updateByteImpl(int val, long adler1);
}