/*
* Copyright 2010 Google Inc.
*
* 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 java.security;
/**
* Message Digest Service Provider Interface - <a
* href="http://java.sun.com/j2se/1.4.2/docs/api/java/security/MessageDigestSpi.html">[Sun's
* docs]</a>.
*/
public abstract class MessageDigestSpi {
protected abstract byte[] engineDigest();
protected int engineDigest(byte[] buf, int offset, int len)
throws DigestException {
byte[] digest = engineDigest();
if (buf.length < digest.length + offset) {
throw new DigestException("Insufficient buffer space for digest");
}
if (len < digest.length) {
throw new DigestException("Length not large enough to hold digest");
}
System.arraycopy(digest, 0, buf, offset, digest.length);
return digest.length;
}
protected int engineGetDigestLength() {
return 0;
}
protected abstract void engineReset();
protected abstract void engineUpdate(byte input);
protected abstract void engineUpdate(byte[] input, int offset, int len);
}