001/**
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *      http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.activemq.util;
018
019/**
020 * Used to convert to hex from byte arrays and back.
021 *
022 *
023 */
024public final class HexSupport {
025
026    private static final String[] HEX_TABLE = new String[]{
027        "00", "01", "02", "03", "04", "05", "06", "07", "08", "09", "0a", "0b", "0c", "0d", "0e", "0f",
028        "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "1a", "1b", "1c", "1d", "1e", "1f",
029        "20", "21", "22", "23", "24", "25", "26", "27", "28", "29", "2a", "2b", "2c", "2d", "2e", "2f",
030        "30", "31", "32", "33", "34", "35", "36", "37", "38", "39", "3a", "3b", "3c", "3d", "3e", "3f",
031        "40", "41", "42", "43", "44", "45", "46", "47", "48", "49", "4a", "4b", "4c", "4d", "4e", "4f",
032        "50", "51", "52", "53", "54", "55", "56", "57", "58", "59", "5a", "5b", "5c", "5d", "5e", "5f",
033        "60", "61", "62", "63", "64", "65", "66", "67", "68", "69", "6a", "6b", "6c", "6d", "6e", "6f",
034        "70", "71", "72", "73", "74", "75", "76", "77", "78", "79", "7a", "7b", "7c", "7d", "7e", "7f",
035        "80", "81", "82", "83", "84", "85", "86", "87", "88", "89", "8a", "8b", "8c", "8d", "8e", "8f",
036        "90", "91", "92", "93", "94", "95", "96", "97", "98", "99", "9a", "9b", "9c", "9d", "9e", "9f",
037        "a0", "a1", "a2", "a3", "a4", "a5", "a6", "a7", "a8", "a9", "aa", "ab", "ac", "ad", "ae", "af",
038        "b0", "b1", "b2", "b3", "b4", "b5", "b6", "b7", "b8", "b9", "ba", "bb", "bc", "bd", "be", "bf",
039        "c0", "c1", "c2", "c3", "c4", "c5", "c6", "c7", "c8", "c9", "ca", "cb", "cc", "cd", "ce", "cf",
040        "d0", "d1", "d2", "d3", "d4", "d5", "d6", "d7", "d8", "d9", "da", "db", "dc", "dd", "de", "df",
041        "e0", "e1", "e2", "e3", "e4", "e5", "e6", "e7", "e8", "e9", "ea", "eb", "ec", "ed", "ee", "ef",
042        "f0", "f1", "f2", "f3", "f4", "f5", "f6", "f7", "f8", "f9", "fa", "fb", "fc", "fd", "fe", "ff",
043    };
044    private static final int[] INT_OFFSETS = new int[]{
045        24,16,8,0
046    };
047
048    private HexSupport() {
049    }
050
051    /**
052     * @param hex
053     * @return array of bytes
054     */
055    public static byte[] toBytesFromHex(String hex) {
056        byte rc[] = new byte[hex.length() / 2];
057        for (int i = 0; i < rc.length; i++) {
058            String h = hex.substring(i * 2, i * 2 + 2);
059            int x = Integer.parseInt(h, 16);
060            rc[i] = (byte) x;
061        }
062        return rc;
063    }
064
065    /**
066     * @param bytes
067     * @return string hex value
068     */
069    public static String toHexFromBytes(byte[] bytes) {
070        StringBuffer rc = new StringBuffer(bytes.length * 2);
071        for (int i = 0; i < bytes.length; i++) {
072            rc.append(HEX_TABLE[0xFF & bytes[i]]);
073        }
074        return rc.toString();
075    }
076
077    /**
078     *
079     * @param value
080     * @param trim if the leading 0's should be trimmed off.
081     * @return string hex value
082     */
083    public static String toHexFromInt(int value, boolean trim) {
084        StringBuffer rc = new StringBuffer(INT_OFFSETS.length*2);
085        for (int i = 0; i < INT_OFFSETS.length; i++) {
086            int b = 0xFF & (value>>INT_OFFSETS[i]);
087            if( !(trim && b == 0) ) {
088                rc.append(HEX_TABLE[b]);
089                trim=false;
090            }
091        }
092
093        return rc.toString();
094    }
095}