1/*
2 * Copyright 2001-2004 The Apache Software Foundation.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package org.apache.commons.codec.binary;
18
19import org.apache.commons.codec.BinaryDecoder;
20import org.apache.commons.codec.BinaryEncoder;
21import org.apache.commons.codec.DecoderException;
22import org.apache.commons.codec.EncoderException;
23
24/**
25 * Hex encoder and decoder.
26 *
27 * @since 1.1
28 * @author Apache Software Foundation
29 * @version $Id: Hex.java,v 1.13 2004/04/18 18:22:33 ggregory Exp $
30 *
31 * @deprecated Please use {@link java.net.URL#openConnection} instead.
32 *     Please visit <a href="http://android-developers.blogspot.com/2011/09/androids-http-clients.html">this webpage</a>
33 *     for further details.
34 */
35@Deprecated
36public class Hex implements BinaryEncoder, BinaryDecoder {
37
38    /**
39     * Used building output as Hex
40     */
41    private static final char[] DIGITS = {
42        '0', '1', '2', '3', '4', '5', '6', '7',
43           '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'
44    };
45
46    /**
47     * Converts an array of characters representing hexidecimal values into an
48     * array of bytes of those same values. The returned array will be half the
49     * length of the passed array, as it takes two characters to represent any
50     * given byte. An exception is thrown if the passed char array has an odd
51     * number of elements.
52     *
53     * @param data An array of characters containing hexidecimal digits
54     * @return A byte array containing binary data decoded from
55     *         the supplied char array.
56     * @throws DecoderException Thrown if an odd number or illegal of characters
57     *         is supplied
58     */
59    public static byte[] decodeHex(char[] data) throws DecoderException {
60
61        int len = data.length;
62
63        if ((len & 0x01) != 0) {
64            throw new DecoderException("Odd number of characters.");
65        }
66
67        byte[] out = new byte[len >> 1];
68
69        // two characters form the hex value.
70        for (int i = 0, j = 0; j < len; i++) {
71            int f = toDigit(data[j], j) << 4;
72            j++;
73            f = f | toDigit(data[j], j);
74            j++;
75            out[i] = (byte) (f & 0xFF);
76        }
77
78        return out;
79    }
80
81    /**
82     * Converts a hexadecimal character to an integer.
83     *
84     * @param ch A character to convert to an integer digit
85     * @param index The index of the character in the source
86     * @return An integer
87     * @throws DecoderException Thrown if ch is an illegal hex character
88     */
89    protected static int toDigit(char ch, int index) throws DecoderException {
90        int digit = Character.digit(ch, 16);
91        if (digit == -1) {
92            throw new DecoderException("Illegal hexadecimal charcter " + ch + " at index " + index);
93        }
94        return digit;
95    }
96
97    /**
98     * Converts an array of bytes into an array of characters representing the hexidecimal values of each byte in order.
99     * The returned array will be double the length of the passed array, as it takes two characters to represent any
100     * given byte.
101     *
102     * @param data
103     *                  a byte[] to convert to Hex characters
104     * @return A char[] containing hexidecimal characters
105     */
106    public static char[] encodeHex(byte[] data) {
107
108        int l = data.length;
109
110           char[] out = new char[l << 1];
111
112           // two characters form the hex value.
113           for (int i = 0, j = 0; i < l; i++) {
114               out[j++] = DIGITS[(0xF0 & data[i]) >>> 4 ];
115               out[j++] = DIGITS[ 0x0F & data[i] ];
116           }
117
118           return out;
119    }
120
121    /**
122     * Converts an array of character bytes representing hexidecimal values into an
123     * array of bytes of those same values. The returned array will be half the
124     * length of the passed array, as it takes two characters to represent any
125     * given byte. An exception is thrown if the passed char array has an odd
126     * number of elements.
127     *
128     * @param array An array of character bytes containing hexidecimal digits
129     * @return A byte array containing binary data decoded from
130     *         the supplied byte array (representing characters).
131     * @throws DecoderException Thrown if an odd number of characters is supplied
132     *                   to this function
133     * @see #decodeHex(char[])
134     */
135    public byte[] decode(byte[] array) throws DecoderException {
136        return decodeHex(new String(array).toCharArray());
137    }
138
139    /**
140     * Converts a String or an array of character bytes representing hexidecimal values into an
141     * array of bytes of those same values. The returned array will be half the
142     * length of the passed String or array, as it takes two characters to represent any
143     * given byte. An exception is thrown if the passed char array has an odd
144     * number of elements.
145     *
146     * @param object A String or, an array of character bytes containing hexidecimal digits
147     * @return A byte array containing binary data decoded from
148     *         the supplied byte array (representing characters).
149     * @throws DecoderException Thrown if an odd number of characters is supplied
150     *                   to this function or the object is not a String or char[]
151     * @see #decodeHex(char[])
152     */
153    public Object decode(Object object) throws DecoderException {
154        try {
155            char[] charArray = object instanceof String ? ((String) object).toCharArray() : (char[]) object;
156            return decodeHex(charArray);
157        } catch (ClassCastException e) {
158            throw new DecoderException(e.getMessage());
159        }
160    }
161
162    /**
163     * Converts an array of bytes into an array of bytes for the characters representing the
164     * hexidecimal values of each byte in order. The returned array will be
165     * double the length of the passed array, as it takes two characters to
166     * represent any given byte.
167     *
168     * @param array a byte[] to convert to Hex characters
169     * @return A byte[] containing the bytes of the hexidecimal characters
170     * @see #encodeHex(byte[])
171     */
172    public byte[] encode(byte[] array) {
173        return new String(encodeHex(array)).getBytes();
174    }
175
176    /**
177     * Converts a String or an array of bytes into an array of characters representing the
178     * hexidecimal values of each byte in order. The returned array will be
179     * double the length of the passed String or array, as it takes two characters to
180     * represent any given byte.
181     *
182     * @param object a String, or byte[] to convert to Hex characters
183     * @return A char[] containing hexidecimal characters
184     * @throws EncoderException Thrown if the given object is not a String or byte[]
185     * @see #encodeHex(byte[])
186     */
187    public Object encode(Object object) throws EncoderException {
188        try {
189            byte[] byteArray = object instanceof String ? ((String) object).getBytes() : (byte[]) object;
190            return encodeHex(byteArray);
191        } catch (ClassCastException e) {
192            throw new EncoderException(e.getMessage());
193        }
194    }
195
196}
197
198