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.nio.charset.StandardCharsets;
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 private Asn1StringUtils()
45 {
46 }
47
48 /**
49 * Helper function that dump a byte in hex form
50 *
51 * @param octet The byte to dump
52 * @return A string representation of the byte
53 */
54 public static String dumpByte( byte octet )
55 {
56 return new String( new byte[]
57 { '0', 'x', HEX_CHAR[( octet & 0x00F0 ) >> 4], HEX_CHAR[octet & 0x000F] }, StandardCharsets.UTF_8 );
58 }
59
60
61 /**
62 * Helper function that dump an array of bytes in hex form
63 *
64 * @param buffer The bytes array to dump
65 * @return A string representation of the array of bytes
66 */
67 public static String dumpBytes( byte[] buffer )
68 {
69 if ( buffer == null )
70 {
71 return "";
72 }
73
74 StringBuilder sb = new StringBuilder();
75
76 for ( byte b : buffer )
77 {
78 sb.append( "0x" ).append( ( char ) ( HEX_CHAR[( b & 0x00F0 ) >> 4] ) ).append(
79 ( char ) ( HEX_CHAR[b & 0x000F] ) ).append( " " );
80 }
81
82 return sb.toString();
83 }
84
85
86 /**
87 * Return UTF-8 encoded byte[] representation of a String
88 *
89 * @param string The string to be transformed to a byte array
90 * @return The transformed byte array
91 */
92 public static byte[] getBytesUtf8( String string )
93 {
94 if ( string == null )
95 {
96 return EMPTY_BYTES;
97 }
98
99 return string.getBytes( StandardCharsets.UTF_8 );
100 }
101
102
103 /**
104 * Transform a string to an array of ASCII bytes, where the byte array will contain
105 * only values in [0, 127].
106 *
107 * @param string The byte array to transform
108 * @return The resulting string
109 */
110 public static byte[] asciiStringToByte( String string )
111 {
112 if ( ( string == null ) || ( string.length() == 0 ) )
113 {
114 return EMPTY_BYTES;
115 }
116
117 byte[] result = new byte[string.length()];
118
119 for ( int i = 0; i < result.length; i++ )
120 {
121 result[i] = ( byte ) string.charAt( i );
122 }
123
124 return result;
125 }
126 }