/*

 * Copyright (c) 1998, 2015, 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.spec;

import java.security.spec.AlgorithmParameterSpec;

/**

 * This class specifies the parameters used with the

 * <a href="http://tools.ietf.org/html/rfc2040"><i>RC5</i></a>

 * algorithm.

 *

 * <p> The parameters consist of a version number, a rounds count, a word

 * size, and optionally an initialization vector (IV) (only in feedback mode).

 *

 * implements the <i>RC5</i> algorithm as supplied by

 * <a href="http://www.rsa.com">RSA Security LLC</a>,

 * or any parties authorized by RSA Security.

 *

 * @author Jan Luehe

 *

 * @since 1.4

 */

public class RC5ParameterSpec implements AlgorithmParameterSpec {

    private byte[] iv = null;

    private int version;

    private int rounds;

    private int wordSize; // the word size in bits

    /**

     * Constructs a parameter set for RC5 from the given version, number of

     * rounds and word size (in bits).

     *

     * @param version the version.

     * @param rounds the number of rounds.

     * @param wordSize the word size in bits.

     */

    public RC5ParameterSpec(int version, int rounds, int wordSize) {

        this.version = version;

        this.rounds = rounds;

        this.wordSize = wordSize;

    }

    /**

     * Constructs a parameter set for RC5 from the given version, number of

     * rounds, word size (in bits), and IV.

     *

     * <p> Note that the size of the IV (block size) must be twice the word

     * size. The bytes that constitute the IV are those between

     *

     * @param version the version.

     * @param rounds the number of rounds.

     * @param wordSize the word size in bits.

     * modification.

     */

    public RC5ParameterSpec(int version, int rounds, int wordSize, byte[] iv) {

        this(version, rounds, wordSize, iv, 0);

    }

    /**

     * Constructs a parameter set for RC5 from the given version, number of

     * rounds, word size (in bits), and IV.

     *

     * Note that the size of the IV (block size), starting at

     * The bytes that constitute the IV are those between

     * inclusive.

     *

     * @param version the version.

     * @param rounds the number of rounds.

     * @param wordSize the word size in bits.

     * inclusive are copied to protect against subsequent modification.

     * {@code (iv.length - offset < 2 * (wordSize / 8))}

     */

    public RC5ParameterSpec(int version, int rounds, int wordSize,

                            byte[] iv, int offset) {

        this.version = version;

        this.rounds = rounds;

        this.wordSize = wordSize;

        if (iv == null) throw new IllegalArgumentException("IV missing");

        int blockSize = (wordSize / 8) * 2;

        if (iv.length - offset < blockSize) {

            throw new IllegalArgumentException("IV too short");

        }

        this.iv = new byte[blockSize];

        System.arraycopy(iv, offset, this.iv, 0, blockSize);

    }

    /**

     * Returns the version.

     *

     * @return the version.

     */

    public int getVersion() {

        return this.version;

    }

    /**

     * Returns the number of rounds.

     *

     * @return the number of rounds.

     */

    public int getRounds() {

        return this.rounds;

    }

    /**

     * Returns the word size in bits.

     *

     * @return the word size in bits.

     */

    public int getWordSize() {

        return this.wordSize;

    }

    /**

     * Returns the IV or null if this parameter set does not contain an IV.

     *

     * @return the IV or null if this parameter set does not contain an IV.

     * Returns a new array each time this method is called.

     */

    public byte[] getIV() {

        return (iv == null? null:iv.clone());

    }

   /**

     * Tests for equality between the specified object and this

     * object. Two RC5ParameterSpec objects are considered equal if their

     * version numbers, number of rounds, word sizes, and IVs are equal.

     *

     * @param obj the object to test for equality with this object.

     *

     * @return true if the objects are considered equal, false if

     */

    public boolean equals(Object obj) {

        if (obj == this) {

            return true;

        }

        if (!(obj instanceof RC5ParameterSpec)) {

            return false;

        }

        RC5ParameterSpec other = (RC5ParameterSpec) obj;

        return ((version == other.version) &&

                (rounds == other.rounds) &&

                (wordSize == other.wordSize) &&

                java.util.Arrays.equals(iv, other.iv));

    }

    /**

     * Calculates a hash code value for the object.

     * Objects that are equal will also have the same hashcode.

     */

    public int hashCode() {

        int retval = 0;

        if (iv != null) {

            for (int i = 1; i < iv.length; i++) {

                retval += iv[i] * i;

            }

        }

        retval += (version + rounds + wordSize);

        return retval;

    }

}