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.directory.api.asn1.util;
21
22
23 import java.io.UnsupportedEncodingException;
24
25
26 /**
27 * Little helper class for the asn1 package.
28 *
29 * @author <a href="mailto:dev@directory.apache.org">Apache Directory Project</a>
30 */
31 public final class Asn1StringUtils
32 {
33 /** Hex chars */
34 private static final byte[] HEX_CHAR = new byte[]
35 { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
36
37 /**
38 * The empty byte[]
39 */
40 public static final byte[] EMPTY_BYTES = new byte[]
41 {};
42
43
44 /**
45 * Helper function that dump a byte in hex form
46 *
47 * @param octet The byte to dump
48 * @return A string representation of the byte
49 */
50 public static String dumpByte( byte octet )
51 {
52 return new String( new byte[]
53 { '0', 'x', HEX_CHAR[( octet & 0x00F0 ) >> 4], HEX_CHAR[octet & 0x000F] } );
54 }
55
56
57 /**
58 * Helper function that dump an array of bytes in hex form
59 *
60 * @param buffer The bytes array to dump
61 * @return A string representation of the array of bytes
62 */
63 public static String dumpBytes( byte[] buffer )
64 {
65 if ( buffer == null )
66 {
67 return "";
68 }
69
70 StringBuffer sb = new StringBuffer();
71
72 for ( byte b : buffer )
73 {
74 sb.append( "0x" ).append( ( char ) ( HEX_CHAR[( b & 0x00F0 ) >> 4] ) ).append(
75 ( char ) ( HEX_CHAR[b & 0x000F] ) ).append( " " );
76 }
77
78 return sb.toString();
79 }
80
81
82 /**
83 * Return UTF-8 encoded byte[] representation of a String
84 *
85 * @param string The string to be transformed to a byte array
86 * @return The transformed byte array
87 */
88 public static byte[] getBytesUtf8( String string )
89 {
90 if ( string == null )
91 {
92 return new byte[0];
93 }
94
95 try
96 {
97 return string.getBytes( "UTF-8" );
98 }
99 catch ( UnsupportedEncodingException uee )
100 {
101 return EMPTY_BYTES;
102 }
103 }
104
105
106 /**
107 * Transform a string to an array of ASCII bytes, where the byte array will contain
108 * only values in [0, 127].
109 *
110 * @param string The byte array to transform
111 * @return The resulting string
112 */
113 public static byte[] asciiStringToByte( String string )
114 {
115 if ( ( string == null ) || ( string.length() == 0 ) )
116 {
117 return EMPTY_BYTES;
118 }
119
120 byte[] result = new byte[string.length()];
121
122 for ( int i = 0; i < result.length; i++ )
123 {
124 result[i] = ( byte ) string.charAt( i );
125 }
126
127 return result;
128 }
129 }