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1   /*
2    *  Licensed to the Apache Software Foundation (ASF) under one
3    *  or more contributor license agreements.  See the NOTICE file
4    *  distributed with this work for additional information
5    *  regarding copyright ownership.  The ASF licenses this file
6    *  to you under the Apache License, Version 2.0 (the
7    *  "License"); you may not use this file except in compliance
8    *  with the License.  You may obtain a copy of the License at
9    *  
10   *    http://www.apache.org/licenses/LICENSE-2.0
11   *  
12   *  Unless required by applicable law or agreed to in writing,
13   *  software distributed under the License is distributed on an
14   *  "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15   *  KIND, either express or implied.  See the License for the
16   *  specific language governing permissions and limitations
17   *  under the License. 
18   *  
19   */
20  package org.apache.mina.common.support;
21  
22  import org.apache.mina.common.ByteBuffer;
23  
24  /**
25   * Provides utility methods for ByteBuffers.
26   * 
27   * @author The Apache Directory Project (mina-dev@directory.apache.org)
28   * @version $Rev: 555855 $, $Date: 2007-07-13 05:19:00 +0200 (Fri, 13 Jul 2007) $
29   */
30  public class ByteBufferHexDumper {
31      private static final byte[] highDigits;
32  
33      private static final byte[] lowDigits;
34  
35      // initialize lookup tables
36      static {
37          final byte[] digits = { '0', '1', '2', '3', '4', '5', '6', '7', '8',
38                  '9', 'A', 'B', 'C', 'D', 'E', 'F' };
39  
40          int i;
41          byte[] high = new byte[256];
42          byte[] low = new byte[256];
43  
44          for (i = 0; i < 256; i++) {
45              high[i] = digits[i >>> 4];
46              low[i] = digits[i & 0x0F];
47          }
48  
49          highDigits = high;
50          lowDigits = low;
51      }
52  
53      public static String getHexdump(ByteBuffer in) {
54          int size = in.remaining();
55  
56          if (size == 0) {
57              return "empty";
58          }
59  
60          StringBuffer out = new StringBuffer((in.remaining() * 3) - 1);
61  
62          int mark = in.position();
63  
64          // fill the first
65          int byteValue = in.get() & 0xFF;
66          out.append((char) highDigits[byteValue]);
67          out.append((char) lowDigits[byteValue]);
68          size--;
69  
70          // and the others, too
71          for (; size > 0; size--) {
72              out.append(' ');
73              byteValue = in.get() & 0xFF;
74              out.append((char) highDigits[byteValue]);
75              out.append((char) lowDigits[byteValue]);
76          }
77  
78          in.position(mark);
79  
80          return out.toString();
81      }
82  }