de.alpharogroup.crypto.aes.HexDump.java Source code

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Here is the source code for de.alpharogroup.crypto.aes.HexDump.java

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/**
 * Copyright (C) 2007 Asterios Raptis
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *         http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package de.alpharogroup.crypto.aes;

import org.apache.commons.codec.DecoderException;
import org.apache.commons.codec.binary.Hex;

/**
 * The Class HexDump.
 */
public class HexDump {
    /** A char array from the hexadecimal digits. */
    private static final char[] HEXADECIMAL_DIGITS = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B',
            'C', 'D', 'E', 'F' };

    /**
     * Transform the given byte array that contains the binary data decoded to a String object. The
     * given byte array comes usually from the {@link HexDump#decodeHex(char[])} method.
     *
     * @param data
     *            the given byte array that contains the binary data decoded
     * @return the decoded string
     */
    public static String decodeHex(final byte[] data) {
        return new String(data);
    }

    /**
     * Transform the given array of characters representing hexadecimal values into an array of
     * bytes.
     * 
     * @param data
     *            the array of characters
     * @return A byte array that contains the binary data decoded from the given char array.
     * @throws DecoderException
     *             is thrown if an odd number or illegal of characters is supplied
     */
    public static byte[] decodeHex(final char[] data) throws DecoderException {
        return Hex.decodeHex(data);
    }

    /**
     * Transform the given array of characters representing hexadecimal values into a String object.
     *
     * @param data
     *            the array of characters
     * @return the decoded string
     * @throws DecoderException
     *             is thrown if an odd number or illegal of characters is supplied
     */
    public static String decodeHexToString(final char[] data) throws DecoderException {
        return new String(Hex.decodeHex(data));
    }

    /**
     * Transform the given array of bytes into an array of characters representing the hexadecimal
     * values of each byte in order.
     * 
     * @param data
     *            the byte array
     * @return the resulted char array of the transformation.
     */
    public static char[] encodeHex(final byte[] data) {
        return encodeHex(data, true);
    }

    /**
     * Transform the given array of bytes into an array of characters representing the hexadecimal
     * values of each byte in order.
     * 
     * @param data
     *            the byte array
     * @param lowerCase
     *            the flag if the result shell be transform in lower case. If true the result is
     *            lowercase otherwise uppercase.
     * @return the resulted char array of the transformation.
     */
    public static char[] encodeHex(final byte[] data, final boolean lowerCase) {
        return Hex.encodeHex(data, lowerCase);
    }

    /**
     * Transform the given String into an array of characters representing the hexadecimal values of
     * each byte in order.
     * 
     * @param data
     *            the byte array
     * @return the resulted char array of the transformation.
     */
    public static char[] encodeHex(final String data) {
        return encodeHex(data.getBytes());
    }

    /**
     * Transform the given {@code int} to a hexadecimal value.
     * 
     * @param i
     *            the integer value to transform
     * @return the char as a hexadecimal value.
     */
    public static char toHex(final int i) {
        return HEXADECIMAL_DIGITS[i & 0xF];
    }

}