HexEncoder


1   
2   /*
3    * Enhydra Java Application Server Project
4    * 
5    * The contents of this file are subject to the Enhydra Public License
6    * Version 1.1 (the "License"); you may not use this file except in
7    * compliance with the License. You may obtain a copy of the License on
8    * the Enhydra web site ( http://www.enhydra.org/ ).
9    * 
10   * Software distributed under the License is distributed on an "AS IS"
11   * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See 
12   * the License for the specific terms governing rights and limitations
13   * under the License.
14   * 
15   * The Initial Developer of the Enhydra Application Server is Lutris
16   * Technologies, Inc. The Enhydra Application Server and portions created
17   * by Lutris Technologies, Inc. are Copyright Lutris Technologies, Inc.
18   * All Rights Reserved.
19   * 
20   * Contributor(s):
21   * 
22   * $Id: HexEncoder.java,v 1.2 2005/03/24 10:51:25 slobodan Exp $
23   */
24  
25  package com.lutris.util;
26  
27  /**
28   * Various conversion methods.
29   * These methods are mostly used to convert internal java data
30   * fields into byte arrays or strings for use in 8 bit ASCII fields.
31   *
32   * @author Mike Ward
33   */
34  public class HexEncoder {
35      /**
36       * Hexadecimal characters corresponding to each half byte value.
37       */
38      private static final char[] HexChars = {
39      '0', '1', '2', '3', '4', '5', '6', '7',
40      '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'
41      };
42  
43      /**
44       * Converts a long integer to an unsigned hexadecimal String.  Treats
45       * the integer as an unsigned 64 bit value and left-pads with the
46       * pad character of the caller's choice.
47       * 
48       * @param value The long integer to convert to a hexadecimal string.
49       * @param len   The total padded length of the string.  If the number
50       *          is larger than the padded length, then this length
51       *          of the string will be the length of the number.
52       * @param pad   The character to use for padding.
53       * @return      Unsigned hexadecimal numeric string representing 
54       *          the specified value.
55       */
56      public static final String   toHexString(long value, int len, char pad) {
57      StringBuffer   sb = new StringBuffer  (Long.toHexString(value));
58      int npad = len - sb.length();
59      while (npad-- > 0) sb.insert(0, pad);
60      return new String  (sb);
61      }
62  
63      /**
64       * Converts an arbitrary array of bytes to ASCII hexadecimal string
65       * form, with two hex characters corresponding to each byte.  The
66       * length of the resultant string in characters will be twice the
67       * length of the specified array of bytes.
68       * 
69       * @param bytes The array of bytes to convert to ASCII hex form.
70       * @return      An ASCII hexadecimal numeric string representing the
71       *          specified array of bytes.
72       */
73      public static final String   toHexString(byte[] bytes) {
74      StringBuffer   sb = new StringBuffer  ();
75      int i;
76      for (i=0; i < bytes.length; i++) {
77          sb.append(HexChars[(bytes[i] >> 4) & 0xf]);
78          sb.append(HexChars[bytes[i] & 0xf]);
79      }
80      return new String  (sb);
81      }
82  }
83  
84  
85
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