gnu.crypto.jce.hash.MessageDigestAdapter Maven / Gradle / Ivy
package gnu.crypto.jce.hash;
// ----------------------------------------------------------------------------
// $Id: MessageDigestAdapter.java,v 1.1 2002/11/11 23:09:41 rsdio Exp $
//
// Copyright (C) 2001, 2002, Free Software Foundation, Inc.
//
// This file is part of GNU Crypto.
//
// GNU Crypto is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2, or (at your option)
// any later version.
//
// GNU Crypto 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
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; see the file COPYING. If not, write to the
//
// Free Software Foundation Inc.,
// 59 Temple Place - Suite 330,
// Boston, MA 02111-1307
// USA
//
// Linking this library statically or dynamically with other modules is
// making a combined work based on this library. Thus, the terms and
// conditions of the GNU General Public License cover the whole
// combination.
//
// As a special exception, the copyright holders of this library give
// you permission to link this library with independent modules to
// produce an executable, regardless of the license terms of these
// independent modules, and to copy and distribute the resulting
// executable under terms of your choice, provided that you also meet,
// for each linked independent module, the terms and conditions of the
// license of that module. An independent module is a module which is
// not derived from or based on this library. If you modify this
// library, you may extend this exception to your version of the
// library, but you are not obligated to do so. If you do not wish to
// do so, delete this exception statement from your version.
// ----------------------------------------------------------------------------
import gnu.crypto.hash.IMessageDigest;
import gnu.crypto.hash.HashFactory;
import java.security.DigestException;
import java.security.MessageDigestSpi;
/**
* The implementation of a generic {@link java.security.MessageDigest} adapter
* class to wrap gnu.crypto hash instances.
*
* This class defines the Service Provider Interface (SPI) for the
* {@link java.security.MessageDigest} class, which provides the functionality
* of a message digest algorithm, such as MD5 or SHA. Message digests are secure
* one-way hash functions that take arbitrary-sized data and output a fixed-
* length hash value.
*
* All the abstract methods in the {@link java.security.MessageDigestSpi} class
* are implemented by this class and all its sub-classes.
*
* All the implementations which subclass this object, and which are serviced by
* the GNU Crypto provider implement the {@link java.lang.Cloneable} interface.
*
* @version $Revision: 1.1 $
*/
class MessageDigestAdapter extends MessageDigestSpi implements Cloneable {
// Constants and variables
// -------------------------------------------------------------------------
/** Our underlying hash instance. */
private IMessageDigest adaptee;
// Constructor(s)
// -------------------------------------------------------------------------
/**
* Trivial protected constructor.
*
* @param mdName the canonical name of the hash algorithm.
*/
protected MessageDigestAdapter(String mdName) {
this(HashFactory.getInstance(mdName));
}
/**
* Private constructor for cloning purposes.
*
* @param adaptee a clone of the underlying hash algorithm instance.
*/
private MessageDigestAdapter(IMessageDigest adaptee) {
super();
this.adaptee = adaptee;
}
// Class methods
// -------------------------------------------------------------------------
// java.security.MessageDigestSpi interface implementation
// -------------------------------------------------------------------------
public Object clone() {
return new MessageDigestAdapter((IMessageDigest) adaptee.clone());
}
public int engineGetDigestLength() {
return adaptee.hashSize();
}
public void engineUpdate(byte input) {
adaptee.update(input);
}
public void engineUpdate(byte[] input, int offset, int len) {
adaptee.update(input, offset, len);
}
public byte[] engineDigest() {
return adaptee.digest();
}
public int engineDigest(byte[] buf, int offset, int len)
throws DigestException {
int result = adaptee.hashSize();
if (len < result) {
throw new DigestException();
}
byte[] md = adaptee.digest();
System.arraycopy(md, 0, buf, offset, result);
return result;
}
public void engineReset() {
adaptee.reset();
}
}