/*
* Copyright (c) 2003-onwards Shaven Puppy Ltd
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* * Neither the name of 'Shaven Puppy' nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package com.shavenpuppy.jglib.util;
/**
* A utility class to decode hexadecimal numbers from strings into byte arrays,
* such as those produced by HexEncoder.
*/
public abstract class HexDecoder {
/** No construction */
private HexDecoder() {}
/**
* Decode a string of hex into a byte array. The string must of course be
* even in length as each pair of digits makes one byte.
* @param in The input String
* @return byte[], or null, if in is null
* @throws IllegalArgumentException if the String is not even-length
* @throws NumberFormatException if the String does not contain only hex digits
*/
public static byte[] decode(String in) throws IllegalArgumentException, NumberFormatException {
if (in == null) {
return null;
}
if ((in.length() & 1) == 1) {
throw new IllegalArgumentException("Input string must be an even length.");
}
byte[] ret = new byte[in.length() >> 1];
for (int i = 0; i < ret.length; i ++) {
ret[i] = (byte) Integer.parseInt(in.substring(i * 2, i * 2 + 2), 16);
}
return ret;
}
}