/*

 * Copyright (c) 1997, 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package javax.crypto;

import java.security.*;

import java.security.spec.*;

/**

 * This class provides a delegate for the identity cipher - one that does not

 * tranform the plaintext.

 *

 * @author  Li Gong

 *

 * @since 1.4

 */

final class NullCipherSpi extends CipherSpi {

    /*

     * Do not let anybody instantiate this directly (protected).

     */

    protected NullCipherSpi() {}

    public void engineSetMode(String mode) {}

    public void engineSetPadding(String padding) {}

    protected int engineGetBlockSize() {

        return 1;

    }

    protected int engineGetOutputSize(int inputLen) {

        return inputLen;

    }

    protected byte[] engineGetIV() {

        byte[] x = new byte[8];

        return x;

    }

    protected AlgorithmParameters engineGetParameters() {

        return null;

    }

    protected void engineInit(int mode, Key key, SecureRandom random) {}

    protected void engineInit(int mode, Key key,

                              AlgorithmParameterSpec params,

                              SecureRandom random) {}

    protected void engineInit(int mode, Key key,

                              AlgorithmParameters params,

                              SecureRandom random) {}

    protected byte[] engineUpdate(byte[] input, int inputOffset,

                                  int inputLen) {

        if (input == null) return null;

        byte[] x = new byte[inputLen];

        System.arraycopy(input, inputOffset, x, 0, inputLen);

        return x;

    }

    protected int engineUpdate(byte[] input, int inputOffset,

                               int inputLen, byte[] output,

                               int outputOffset) {

        if (input == null) return 0;

        System.arraycopy(input, inputOffset, output, outputOffset, inputLen);

        return inputLen;

    }

    protected byte[] engineDoFinal(byte[] input, int inputOffset,

                                   int inputLen)

    {

        return engineUpdate(input, inputOffset, inputLen);

    }

    protected int engineDoFinal(byte[] input, int inputOffset,

                                int inputLen, byte[] output,

                                int outputOffset)

    {

        return engineUpdate(input, inputOffset, inputLen,

                            output, outputOffset);

    }

    protected int engineGetKeySize(Key key)

    {

        return 0;

    }

}