1 //
2 // ========================================================================
3 // Copyright (c) 1995-2013 Mort Bay Consulting Pty. Ltd.
4 // ------------------------------------------------------------------------
5 // All rights reserved. This program and the accompanying materials
6 // are made available under the terms of the Eclipse Public License v1.0
7 // and Apache License v2.0 which accompanies this distribution.
8 //
9 // The Eclipse Public License is available at
10 // http://www.eclipse.org/legal/epl-v10.html
11 //
12 // The Apache License v2.0 is available at
13 // http://www.opensource.org/licenses/apache2.0.php
14 //
15 // You may elect to redistribute this code under either of these licenses.
16 // ========================================================================
17 //
18
19 package org.eclipse.jetty.util;
20
21 import java.io.IOException;
22
23 /* ------------------------------------------------------------ */
24 /**
25 * Utf8 Appendable abstract base class
26 *
27 * This abstract class wraps a standard {@link java.lang.Appendable} and provides methods to append UTF-8 encoded bytes, that are converted into characters.
28 *
29 * 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.
30 *
31 * The UTF-8 decoding is done by this class and no additional buffers or Readers are used. The UTF-8 code was inspired by
32 * http://bjoern.hoehrmann.de/utf-8/decoder/dfa/
33 *
34 * License information for Bjoern Hoehrmann's code:
35 *
36 * Copyright (c) 2008-2009 Bjoern Hoehrmann <bjoern@hoehrmann.de>
37 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal
38 * in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
39 * copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
40 *
41 * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
42 *
43 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
44 * 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
45 * 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.
46 **/
47 public abstract class Utf8Appendable
48 {
49 public static final char REPLACEMENT = '\ufffd';
50 private static final int UTF8_ACCEPT = 0;
51 private static final int UTF8_REJECT = 12;
52
53 protected final Appendable _appendable;
54 protected int _state = UTF8_ACCEPT;
55
56 private static final byte[] BYTE_TABLE =
57 {
58 // The first part of the table maps bytes to character classes that
59 // to reduce the size of the transition table and create bitmasks.
60 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,
61 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,
62 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,
63 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,
64 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,
65 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,
66 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,
67 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
68 };
69
70 private static final byte[] TRANS_TABLE =
71 {
72 // The second part is a transition table that maps a combination
73 // of a state of the automaton and a character class to a state.
74 0,12,24,36,60,96,84,12,12,12,48,72, 12,12,12,12,12,12,12,12,12,12,12,12,
75 12, 0,12,12,12,12,12, 0,12, 0,12,12, 12,24,12,12,12,12,12,24,12,24,12,12,
76 12,12,12,12,12,12,12,24,12,12,12,12, 12,24,12,12,12,12,12,12,12,24,12,12,
77 12,12,12,12,12,12,12,36,12,36,12,12, 12,36,12,12,12,12,12,36,12,36,12,12,
78 12,36,12,12,12,12,12,12,12,12,12,12
79 };
80
81 private int _codep;
82
83 public Utf8Appendable(Appendable appendable)
84 {
85 _appendable = appendable;
86 }
87
88 public abstract int length();
89
90 protected void reset()
91 {
92 _state = UTF8_ACCEPT;
93 }
94
95 public void append(byte b)
96 {
97 try
98 {
99 appendByte(b);
100 }
101 catch (IOException e)
102 {
103 throw new RuntimeException(e);
104 }
105 }
106
107 public void append(byte[] b, int offset, int length)
108 {
109 try
110 {
111 int end = offset + length;
112 for (int i = offset; i < end; i++)
113 appendByte(b[i]);
114 }
115 catch (IOException e)
116 {
117 throw new RuntimeException(e);
118 }
119 }
120
121 public boolean append(byte[] b, int offset, int length, int maxChars)
122 {
123 try
124 {
125 int end = offset + length;
126 for (int i = offset; i < end; i++)
127 {
128 if (length() > maxChars)
129 return false;
130 appendByte(b[i]);
131 }
132 return true;
133 }
134 catch (IOException e)
135 {
136 throw new RuntimeException(e);
137 }
138 }
139
140 protected void appendByte(byte b) throws IOException
141 {
142
143 if (b > 0 && _state == UTF8_ACCEPT)
144 {
145 _appendable.append((char)(b & 0xFF));
146 }
147 else
148 {
149 int i = b & 0xFF;
150 int type = BYTE_TABLE[i];
151 _codep = _state == UTF8_ACCEPT ? (0xFF >> type) & i : (i & 0x3F) | (_codep << 6);
152 int next = TRANS_TABLE[_state + type];
153
154 switch(next)
155 {
156 case UTF8_ACCEPT:
157 _state=next;
158 if (_codep < Character.MIN_HIGH_SURROGATE)
159 {
160 _appendable.append((char)_codep);
161 }
162 else
163 {
164 for (char c : Character.toChars(_codep))
165 _appendable.append(c);
166 }
167 break;
168
169 case UTF8_REJECT:
170 String reason = "byte "+TypeUtil.toHexString(b)+" in state "+(_state/12);
171 _codep=0;
172 _state = UTF8_ACCEPT;
173 _appendable.append(REPLACEMENT);
174 throw new NotUtf8Exception(reason);
175
176 default:
177 _state=next;
178
179 }
180 }
181 }
182
183 public boolean isUtf8SequenceComplete()
184 {
185 return _state == UTF8_ACCEPT;
186 }
187
188 public static class NotUtf8Exception extends IllegalArgumentException
189 {
190 public NotUtf8Exception(String reason)
191 {
192 super("Not valid UTF8! "+reason);
193 }
194 }
195 }