/*
* Copyright (c) 1998, 2007, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code 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
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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*/
package javax.crypto;
import java.security.*;
import java.security.spec.*;
import java.nio.ByteBuffer;
/**
* This class defines the <i>Service Provider Interface</i> (<b>SPI</b>)
* for the <code>Mac</code> class.
* All the abstract methods in this class must be implemented by each
* cryptographic service provider who wishes to supply the implementation
* of a particular MAC algorithm.
*
* <p> Implementations are free to implement the Cloneable interface.
*
* @author Jan Luehe
*
* @since 1.4
*/
public abstract class MacSpi {
/**
* Returns the length of the MAC in bytes.
*
* @return the MAC length in bytes.
*/
protected abstract int engineGetMacLength();
/**
* Initializes the MAC with the given (secret) key and algorithm
* parameters.
*
* @param key the (secret) key.
* @param params the algorithm parameters.
*
* @exception InvalidKeyException if the given key is inappropriate for
* initializing this MAC.
* @exception InvalidAlgorithmParameterException if the given algorithm
* parameters are inappropriate for this MAC.
*/
protected abstract void engineInit(Key key,
AlgorithmParameterSpec params)
throws InvalidKeyException, InvalidAlgorithmParameterException ;
/**
* Processes the given byte.
*
* @param input the input byte to be processed.
*/
protected abstract void engineUpdate(byte input);
/**
* Processes the first <code>len</code> bytes in <code>input</code>,
* starting at <code>offset</code> inclusive.
*
* @param input the input buffer.
* @param offset the offset in <code>input</code> where the input starts.
* @param len the number of bytes to process.
*/
protected abstract void engineUpdate(byte[] input, int offset, int len);
/**
* Processes <code>input.remaining()</code> bytes in the ByteBuffer
* <code>input</code>, starting at <code>input.position()</code>.
* Upon return, the buffer's position will be equal to its limit;
* its limit will not have changed.
*
* <p>Subclasses should consider overriding this method if they can
* process ByteBuffers more efficiently than byte arrays.
*
* @param input the ByteBuffer
* @since 1.5
*/
protected void engineUpdate(ByteBuffer input) {
if (input.hasRemaining() == false) {
return;
}
if (input.hasArray()) {
byte[] b = input.array();
int ofs = input.arrayOffset();
int pos = input.position();
int lim = input.limit();
engineUpdate(b, ofs + pos, lim - pos);
input.position(lim);
} else {
int len = input.remaining();
byte[] b = new byte[CipherSpi.getTempArraySize(len)];
while (len > 0) {
int chunk = Math.min(len, b.length);
input.get(b, 0, chunk);
engineUpdate(b, 0, chunk);
len -= chunk;
}
}
}
/**
* Completes the MAC computation and resets the MAC for further use,
* maintaining the secret key that the MAC was initialized with.
*
* @return the MAC result.
*/
protected abstract byte[] engineDoFinal();
/**
* Resets the MAC for further use, maintaining the secret key that the
* MAC was initialized with.
*/
protected abstract void engineReset();
/**
* Returns a clone if the implementation is cloneable.
*
* @return a clone if the implementation is cloneable.
*
* @exception CloneNotSupportedException if this is called
* on an implementation that does not support <code>Cloneable</code>.
*/
public Object clone() throws CloneNotSupportedException {
if (this instanceof Cloneable) {
return super.clone();
} else {
throw new CloneNotSupportedException();
}
}
}