001/*
002 * $HeadURL: file:///opt/dev/not-yet-commons-ssl-SVN-repo/tags/commons-ssl-0.3.17/src/java/org/apache/commons/ssl/util/Hex.java $
003 * $Revision: 121 $
004 * $Date: 2007-11-13 21:26:57 -0800 (Tue, 13 Nov 2007) $
005 *
006 * ====================================================================
007 * Licensed to the Apache Software Foundation (ASF) under one
008 * or more contributor license agreements.  See the NOTICE file
009 * distributed with this work for additional information
010 * regarding copyright ownership.  The ASF licenses this file
011 * to you under the Apache License, Version 2.0 (the
012 * "License"); you may not use this file except in compliance
013 * with the License.  You may obtain a copy of the License at
014 *
015 *   http://www.apache.org/licenses/LICENSE-2.0
016 *
017 * Unless required by applicable law or agreed to in writing,
018 * software distributed under the License is distributed on an
019 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
020 * KIND, either express or implied.  See the License for the
021 * specific language governing permissions and limitations
022 * under the License.
023 * ====================================================================
024 *
025 * This software consists of voluntary contributions made by many
026 * individuals on behalf of the Apache Software Foundation.  For more
027 * information on the Apache Software Foundation, please see
028 * <http://www.apache.org/>.
029 *
030 */
031
032package org.apache.commons.ssl.util;
033
034/**
035 * Utility class for dealing with hex-encoding of binary data.
036 *
037 * @author <a href="mailto:juliusdavies@cucbc.com">juliusdavies@gmail.com</a>
038 * @since 13-Nov-2007
039 */
040public class Hex {
041
042    public static byte[] decode(String s) {
043        byte[] b = new byte[s.length() / 2];
044        for (int i = 0; i < b.length; i++) {
045            String hex = s.substring(2 * i, 2 * (i + 1));
046            b[i] = (byte) Integer.parseInt(hex, 16);
047        }
048        return b;
049    }
050
051    public static byte[] decode(byte[] hexString) {
052        byte[] b = new byte[hexString.length / 2];
053        char[] chars = new char[2];
054        for (int i = 0; i < b.length; i++) {
055            chars[0] = (char) hexString[2 * i];
056            chars[1] = (char) hexString[2 * i + 1];
057            String hex = new String(chars);
058            b[i] = (byte) Integer.parseInt(hex, 16);
059        }
060        return b;
061    }
062
063    public static String encode(byte[] b) {
064        return encode(b, 0, b.length);
065    }
066
067    public static String encode(byte[] b, int offset, int length) {
068        StringBuffer buf = new StringBuffer();
069        int len = Math.min(offset + length, b.length);
070        for (int i = offset; i < len; i++) {
071            int c = (int) b[i];
072            if (c < 0) {
073                c = c + 256;
074            }
075            if (c >= 0 && c <= 15) {
076                buf.append('0');
077            }
078            buf.append(Integer.toHexString(c));
079        }
080        return buf.toString();
081    }
082
083}