Java Hex Convert To fromHex(String hex)

Description

from Hex

License

Open Source License

Declaration

public static byte[] fromHex(String hex) 

Method Source Code

//package com.java2s;
/**// w w w. j a  v  a  2s . c o m
 * Copyright (C) 2013, Moss Computing Inc.
 *
 * This file is part of rpcutil.
 *
 * rpcutil is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * rpcutil 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 for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with rpcutil; see the file COPYING.  If not, write to the
 * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301 USA.
 *
 * Linking this library statically or dynamically with other modules is
 * making a combined work based on this library.  Thus, the terms and
 * conditions of the GNU General Public License cover the whole
 * combination.
 *
 * As a special exception, the copyright holders of this library give you
 * permission to link this library with independent modules to produce an
 * executable, regardless of the license terms of these independent
 * modules, and to copy and distribute the resulting executable under
 * terms of your choice, provided that you also meet, for each linked
 * independent module, the terms and conditions of the license of that
 * module.  An independent module is a module which is not derived from
 * or based on this library.  If you modify this library, you may extend
 * this exception to your version of the library, but you are not
 * obligated to do so.  If you do not wish to do so, delete this
 * exception statement from your version.
 */

public class Main {
    public static byte[] fromHex(String hex) {

        if (hex.length() % 2 != 0) {
            hex = "0" + hex;
        }

        int byteCount = hex.length() / 2;

        byte[] bytes = new byte[byteCount];

        for (int i = 0; i < byteCount; i++) {
            int index = i * 2;

            char upper = hex.charAt(index);
            //          System.out.println("Upper: " + upper);

            int upperValue = hexToByte(upper) << 4;
            //          System.out.println("Upper Value: " + upperValue);

            char lower = hex.charAt(index + 1);
            //          System.out.println("Lower: " + lower);

            int lowerValue = hexToByte(lower);
            //          System.out.println("Lower Value: " + lowerValue);

            int value = upperValue + lowerValue;
            //          System.out.println("Value: " + value);

            bytes[i] = (byte) value;
        }

        return bytes;
    }

    private static int hexToByte(char hex) {

        int offset;

        if (hex >= '0' && hex <= '9') {
            offset = -48;
        } else if (hex >= 'A' && hex <= 'F') {
            offset = -55;
        } else if (hex >= 'a' && hex <= 'f') {
            offset = -87;
        } else {
            throw new RuntimeException("Not a hexidecimal character: " + hex);
        }

        int hexValue = (int) hex;
        return hexValue + offset;
    }
}

Related

1. fromHex(final String hexValue)
2. fromHex(final String s)
3. fromHex(final String string, final int offset, final int count)
4. fromHex(String bytesString)
5. fromHex(String encoded)
6. fromHex(String hex)
7. fromHex(String hex)
8. fromHex(String hex)
9. fromHex(String hex)