/*
 * Copyright (c) 1997, 2022, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
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 */

package javax.crypto;

import java.security.*;
import java.security.spec.*;

/**
 * This class provides a delegate for the identity cipher - one that does not
 * transform the plain text.
 *
 * @author  Li Gong
 * @see NullCipher
 *
 * @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() {
        return new byte[8];
    }

    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;
    }
}
