1/*
2 * $HeadURL: http://svn.apache.org/repos/asf/httpcomponents/httpcore/trunk/module-main/src/main/java/org/apache/http/util/EncodingUtils.java $
3 * $Revision: 503413 $
4 * $Date: 2007-02-04 06:22:14 -0800 (Sun, 04 Feb 2007) $
5 *
6 * ====================================================================
7 * Licensed to the Apache Software Foundation (ASF) under one
8 * or more contributor license agreements.  See the NOTICE file
9 * distributed with this work for additional information
10 * regarding copyright ownership.  The ASF licenses this file
11 * to you under the Apache License, Version 2.0 (the
12 * "License"); you may not use this file except in compliance
13 * with the License.  You may obtain a copy of the License at
14 *
15 *   http://www.apache.org/licenses/LICENSE-2.0
16 *
17 * Unless required by applicable law or agreed to in writing,
18 * software distributed under the License is distributed on an
19 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
20 * KIND, either express or implied.  See the License for the
21 * specific language governing permissions and limitations
22 * under the License.
23 * ====================================================================
24 *
25 * This software consists of voluntary contributions made by many
26 * individuals on behalf of the Apache Software Foundation.  For more
27 * information on the Apache Software Foundation, please see
28 * <http://www.apache.org/>.
29 *
30 */
31package org.apache.http.util;
32
33import java.io.UnsupportedEncodingException;
34
35import org.apache.http.protocol.HTTP;
36
37/**
38 * The home for utility methods that handle various encoding tasks.
39 *
40 * @author Michael Becke
41 * @author <a href="mailto:oleg at ural.ru">Oleg Kalnichevski</a>
42 *
43 * @since 4.0
44 */
45public final class EncodingUtils {
46
47    /**
48     * Converts the byte array of HTTP content characters to a string. If
49     * the specified charset is not supported, default system encoding
50     * is used.
51     *
52     * @param data the byte array to be encoded
53     * @param offset the index of the first byte to encode
54     * @param length the number of bytes to encode
55     * @param charset the desired character encoding
56     * @return The result of the conversion.
57     */
58    public static String getString(
59        final byte[] data,
60        int offset,
61        int length,
62        String charset
63    ) {
64
65        if (data == null) {
66            throw new IllegalArgumentException("Parameter may not be null");
67        }
68
69        if (charset == null || charset.length() == 0) {
70            throw new IllegalArgumentException("charset may not be null or empty");
71        }
72
73        try {
74            return new String(data, offset, length, charset);
75        } catch (UnsupportedEncodingException e) {
76            return new String(data, offset, length);
77        }
78    }
79
80
81    /**
82     * Converts the byte array of HTTP content characters to a string. If
83     * the specified charset is not supported, default system encoding
84     * is used.
85     *
86     * @param data the byte array to be encoded
87     * @param charset the desired character encoding
88     * @return The result of the conversion.
89     */
90    public static String getString(final byte[] data, final String charset) {
91        if (data == null) {
92            throw new IllegalArgumentException("Parameter may not be null");
93        }
94        return getString(data, 0, data.length, charset);
95    }
96
97    /**
98     * Converts the specified string to a byte array.  If the charset is not supported the
99     * default system charset is used.
100     *
101     * @param data the string to be encoded
102     * @param charset the desired character encoding
103     * @return The resulting byte array.
104     */
105    public static byte[] getBytes(final String data, final String charset) {
106
107        if (data == null) {
108            throw new IllegalArgumentException("data may not be null");
109        }
110
111        if (charset == null || charset.length() == 0) {
112            throw new IllegalArgumentException("charset may not be null or empty");
113        }
114
115        try {
116            return data.getBytes(charset);
117        } catch (UnsupportedEncodingException e) {
118            return data.getBytes();
119        }
120    }
121
122    /**
123     * Converts the specified string to byte array of ASCII characters.
124     *
125     * @param data the string to be encoded
126     * @return The string as a byte array.
127     */
128    public static byte[] getAsciiBytes(final String data) {
129
130        if (data == null) {
131            throw new IllegalArgumentException("Parameter may not be null");
132        }
133
134        try {
135            return data.getBytes(HTTP.US_ASCII);
136        } catch (UnsupportedEncodingException e) {
137            throw new Error("HttpClient requires ASCII support");
138        }
139    }
140
141    /**
142     * Converts the byte array of ASCII characters to a string. This method is
143     * to be used when decoding content of HTTP elements (such as response
144     * headers)
145     *
146     * @param data the byte array to be encoded
147     * @param offset the index of the first byte to encode
148     * @param length the number of bytes to encode
149     * @return The string representation of the byte array
150     */
151    public static String getAsciiString(final byte[] data, int offset, int length) {
152
153        if (data == null) {
154            throw new IllegalArgumentException("Parameter may not be null");
155        }
156
157        try {
158            return new String(data, offset, length, HTTP.US_ASCII);
159        } catch (UnsupportedEncodingException e) {
160            throw new Error("HttpClient requires ASCII support");
161        }
162    }
163
164    /**
165     * Converts the byte array of ASCII characters to a string. This method is
166     * to be used when decoding content of HTTP elements (such as response
167     * headers)
168     *
169     * @param data the byte array to be encoded
170     * @return The string representation of the byte array
171     */
172    public static String getAsciiString(final byte[] data) {
173        if (data == null) {
174            throw new IllegalArgumentException("Parameter may not be null");
175        }
176        return getAsciiString(data, 0, data.length);
177    }
178
179    /**
180     * This class should not be instantiated.
181     */
182    private EncodingUtils() {
183    }
184
185}
186