1 // ========================================================================
2 // Copyright (c) 2006-2009 Mort Bay Consulting Pty. Ltd.
3 // ------------------------------------------------------------------------
4 // All rights reserved. This program and the accompanying materials
5 // are made available under the terms of the Eclipse Public License v1.0
6 // and Apache License v2.0 which accompanies this distribution.
7 // The Eclipse Public License is available at
8 // http://www.eclipse.org/legal/epl-v10.html
9 // The Apache License v2.0 is available at
10 // http://www.opensource.org/licenses/apache2.0.php
11 // You may elect to redistribute this code under either of these licenses.
12 // ========================================================================
13 package org.eclipse.jetty.util;
14
15 import java.io.IOException;
16
17 /* ------------------------------------------------------------ */
18 /**
19 * Utf8 Appendable abstract base class
20 *
21 * This abstract class wraps a standard {@link java.lang.Appendable} and provides methods to append UTF-8 encoded bytes, that are converted into characters.
22 *
23 * This class is stateful and up to 4 calls to {@link #append(byte)} may be needed before state a character is appended to the string buffer.
24 *
25 * The UTF-8 decoding is done by this class and no additional buffers or Readers are used. The UTF-8 code was inspired by
26 * http://bjoern.hoehrmann.de/utf-8/decoder/dfa/
27 *
28 * License information for Bjoern Hoehrmann's code:
29 *
30 * Copyright (c) 2008-2009 Bjoern Hoehrmann <bjoern@hoehrmann.de>
31 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal
32 * in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
33 * copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
34 *
35 * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
36 *
37 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
38 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
39 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
40 **/
41 public abstract class Utf8Appendable
42 {
43 private final char REPLACEMENT = '\ufffd';
44 private static final int UTF8_ACCEPT = 0;
45 private static final int UTF8_REJECT = 12;
46
47 protected final Appendable _appendable;
48 protected int _state = UTF8_ACCEPT;
49
50 private static final byte[] BYTE_TABLE =
51 {
52 // The first part of the table maps bytes to character classes that
53 // to reduce the size of the transition table and create bitmasks.
54 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
55 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
56 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
57 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
58 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1, 9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,9,
59 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
60 8,8,2,2,2,2,2,2,2,2,2,2,2,2,2,2, 2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,2,
61 10,3,3,3,3,3,3,3,3,3,3,3,3,4,3,3, 11,6,6,6,5,8,8,8,8,8,8,8,8,8,8,8
62 };
63
64 private static final byte[] TRANS_TABLE =
65 {
66 // The second part is a transition table that maps a combination
67 // of a state of the automaton and a character class to a state.
68 0,12,24,36,60,96,84,12,12,12,48,72, 12,12,12,12,12,12,12,12,12,12,12,12,
69 12, 0,12,12,12,12,12, 0,12, 0,12,12, 12,24,12,12,12,12,12,24,12,24,12,12,
70 12,12,12,12,12,12,12,24,12,12,12,12, 12,24,12,12,12,12,12,12,12,24,12,12,
71 12,12,12,12,12,12,12,36,12,36,12,12, 12,36,12,12,12,12,12,36,12,36,12,12,
72 12,36,12,12,12,12,12,12,12,12,12,12
73 };
74
75 private int _codep;
76
77 public Utf8Appendable(Appendable appendable)
78 {
79 _appendable = appendable;
80 }
81
82 public abstract int length();
83
84 protected void reset()
85 {
86 _state = UTF8_ACCEPT;
87 }
88
89 public void append(byte b)
90 {
91 try
92 {
93 appendByte(b);
94 }
95 catch (IOException e)
96 {
97 throw new RuntimeException(e);
98 }
99 }
100
101 public void append(byte[] b, int offset, int length)
102 {
103 try
104 {
105 int end = offset + length;
106 for (int i = offset; i < end; i++)
107 appendByte(b[i]);
108 }
109 catch (IOException e)
110 {
111 throw new RuntimeException(e);
112 }
113 }
114
115 public boolean append(byte[] b, int offset, int length, int maxChars)
116 {
117 try
118 {
119 int end = offset + length;
120 for (int i = offset; i < end; i++)
121 {
122 if (length() > maxChars)
123 return false;
124 appendByte(b[i]);
125 }
126 return true;
127 }
128 catch (IOException e)
129 {
130 throw new RuntimeException(e);
131 }
132 }
133
134 protected void appendByte(byte b) throws IOException
135 {
136
137 if (b > 0 && isUtf8SequenceComplete())
138 {
139 _appendable.append((char)(b & 0xFF));
140 }
141 else
142 {
143 int i = b & 0xFF;
144 int type = BYTE_TABLE[i];
145 _codep = isUtf8SequenceComplete() ? (0xFF >> type) & i : (i & 0x3F) | (_codep << 6);
146 _state = TRANS_TABLE[_state + type];
147
148 if (isUtf8SequenceComplete())
149 {
150 if (_codep < Character.MIN_HIGH_SURROGATE)
151 {
152 _appendable.append((char)_codep);
153 }
154 else
155 {
156 for (char c : Character.toChars(_codep))
157 _appendable.append(c);
158 }
159 }
160 else if (_state == UTF8_REJECT)
161 {
162 _codep=0;
163 _state = UTF8_ACCEPT;
164 _appendable.append(REPLACEMENT);
165 throw new NotUtf8Exception();
166 }
167 }
168 }
169
170 protected boolean isUtf8SequenceComplete()
171 {
172 return _state == UTF8_ACCEPT;
173 }
174
175 public static class NotUtf8Exception extends IllegalArgumentException
176 {
177 public NotUtf8Exception()
178 {
179 super("Not valid UTF8!");
180 }
181 }
182 }