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Java > Open Source Codes > org > apache > geronimo > util > encoders > HexEncoder


1 /**
2  * Licensed to the Apache Software Foundation (ASF) under one or more
3  * contributor license agreements. See the NOTICE file distributed with
4  * this work for additional information regarding copyright ownership.
5  * The ASF licenses this file to You under the Apache License, Version 2.0
6  * (the "License"); you may not use this file except in compliance with
7  * the License. You may obtain a copy of the License at
8  *
9  * http://www.apache.org/licenses/LICENSE-2.0
10  *
11  * Unless required by applicable law or agreed to in writing, software
12  * distributed under the License is distributed on an "AS IS" BASIS,
13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14  * See the License for the specific language governing permissions and
15  * limitations under the License.
16  */
17
18 package org.apache.geronimo.util.encoders;
19
20 import java.io.IOException JavaDoc;
21 import java.io.OutputStream JavaDoc;
22
23 public class HexEncoder
24     implements Encoder
25 {
26     protected final byte[] encodingTable =
27         {
28             (byte)'0', (byte)'1', (byte)'2', (byte)'3', (byte)'4', (byte)'5', (byte)'6', (byte)'7',
29             (byte)'8', (byte)'9', (byte)'a', (byte)'b', (byte)'c', (byte)'d', (byte)'e', (byte)'f'
30         };
31
32     /*
33      * set up the decoding table.
34      */
35     protected final byte[] decodingTable = new byte[128];
36
37     protected void initialiseDecodingTable()
38     {
39         for (int i = 0; i < encodingTable.length; i++)
40         {
41             decodingTable[encodingTable[i]] = (byte)i;
42         }
43
44         decodingTable['A'] = decodingTable['a'];
45         decodingTable['B'] = decodingTable['b'];
46         decodingTable['C'] = decodingTable['c'];
47         decodingTable['D'] = decodingTable['d'];
48         decodingTable['E'] = decodingTable['e'];
49         decodingTable['F'] = decodingTable['f'];
50     }
51
52     public HexEncoder()
53     {
54         initialiseDecodingTable();
55     }
56
57     /**
58      * encode the input data producing a Hex output stream.
59      *
60      * @return the number of bytes produced.
61      */
62     public int encode(
63         byte[] data,
64         int off,
65         int length,
66         OutputStream JavaDoc out)
67         throws IOException JavaDoc
68     {
69         for (int i = off; i < (off + length); i++)
70         {
71             int v = data[i] & 0xff;
72
73             out.write(encodingTable[(v >>> 4)]);
74             out.write(encodingTable[v & 0xf]);
75         }
76
77         return length * 2;
78     }
79
80     private boolean ignore(
81         char c)
82     {
83         return (c == '\n' || c =='\r' || c == '\t' || c == ' ');
84     }
85
86     /**
87      * decode the Hex encoded byte data writing it to the given output stream,
88      * whitespace characters will be ignored.
89      *
90      * @return the number of bytes produced.
91      */
92     public int decode(
93         byte[] data,
94         int off,
95         int length,
96         OutputStream JavaDoc out)
97         throws IOException JavaDoc
98     {
99         byte[] bytes;
100         byte b1, b2;
101         int outLen = 0;
102
103         int end = off + length;
104
105         while (end > 0)
106         {
107             if (!ignore((char)data[end - 1]))
108             {
109                 break;
110             }
111
112             end--;
113         }
114
115         int i = off;
116         while (i < end)
117         {
118             while (i < end && ignore((char)data[i]))
119             {
120                 i++;
121             }
122
123             b1 = decodingTable[data[i++]];
124
125             while (i < end && ignore((char)data[i]))
126             {
127                 i++;
128             }
129
130             b2 = decodingTable[data[i++]];
131
132             out.write((b1 << 4) | b2);
133
134             outLen++;
135         }
136
137         return outLen;
138     }
139
140     /**
141      * decode the Hex encoded String data writing it to the given output stream,
142      * whitespace characters will be ignored.
143      *
144      * @return the number of bytes produced.
145      */
146     public int decode(
147         String JavaDoc data,
148         OutputStream JavaDoc out)
149         throws IOException JavaDoc
150     {
151         byte[] bytes;
152         byte b1, b2, b3, b4;
153         int length = 0;
154
155         int end = data.length();
156
157         while (end > 0)
158         {
159             if (!ignore(data.charAt(end - 1)))
160             {
161                 break;
162             }
163
164             end--;
165         }
166
167         int i = 0;
168         while (i < end)
169         {
170             while (i < end && ignore(data.charAt(i)))
171             {
172                 i++;
173             }
174
175             b1 = decodingTable[data.charAt(i++)];
176
177             while (i < end && ignore(data.charAt(i)))
178             {
179                 i++;
180             }
181
182             b2 = decodingTable[data.charAt(i++)];
183
184             out.write((b1 << 4) | b2);
185
186             length++;
187         }
188
189         return length;
190     }
191 }
192
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