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 import org.eclipse.jetty.util.log.Log;
24 import org.eclipse.jetty.util.log.Logger;
25
26 /* ------------------------------------------------------------ */
27 /**
28 * Utf8 Appendable abstract base class
29 *
30 * This abstract class wraps a standard {@link java.lang.Appendable} and provides methods to append UTF-8 encoded bytes, that are converted into characters.
31 *
32 * 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.
33 *
34 * The UTF-8 decoding is done by this class and no additional buffers or Readers are used. The UTF-8 code was inspired by
35 * http://bjoern.hoehrmann.de/utf-8/decoder/dfa/
36 *
37 * License information for Bjoern Hoehrmann's code:
38 *
39 * Copyright (c) 2008-2009 Bjoern Hoehrmann <bjoern@hoehrmann.de>
40 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal
41 * in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
42 * copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
43 *
44 * The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
45 *
46 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
47 * 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
48 * 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.
49 **/
50 public abstract class Utf8Appendable
51 {
52 protected static final Logger LOG = Log.getLogger(Utf8Appendable.class);
53 public static final char REPLACEMENT = '\ufffd';
54 private static final int UTF8_ACCEPT = 0;
55 private static final int UTF8_REJECT = 12;
56
57 protected final Appendable _appendable;
58 protected int _state = UTF8_ACCEPT;
59
60 private static final byte[] BYTE_TABLE =
61 {
62 // The first part of the table maps bytes to character classes that
63 // to reduce the size of the transition table and create bitmasks.
64 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,
65 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,
66 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,
67 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,
68 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,
69 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,
70 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,
71 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
72 };
73
74 private static final byte[] TRANS_TABLE =
75 {
76 // The second part is a transition table that maps a combination
77 // of a state of the automaton and a character class to a state.
78 0,12,24,36,60,96,84,12,12,12,48,72, 12,12,12,12,12,12,12,12,12,12,12,12,
79 12, 0,12,12,12,12,12, 0,12, 0,12,12, 12,24,12,12,12,12,12,24,12,24,12,12,
80 12,12,12,12,12,12,12,24,12,12,12,12, 12,24,12,12,12,12,12,12,12,24,12,12,
81 12,12,12,12,12,12,12,36,12,36,12,12, 12,36,12,12,12,12,12,36,12,36,12,12,
82 12,36,12,12,12,12,12,12,12,12,12,12
83 };
84
85 private int _codep;
86
87 public Utf8Appendable(Appendable appendable)
88 {
89 _appendable = appendable;
90 }
91
92 public abstract int length();
93
94 protected void reset()
95 {
96 _state = UTF8_ACCEPT;
97 }
98
99 public void append(byte b)
100 {
101 try
102 {
103 appendByte(b);
104 }
105 catch (IOException e)
106 {
107 throw new RuntimeException(e);
108 }
109 }
110
111 public void append(byte[] b, int offset, int length)
112 {
113 try
114 {
115 int end = offset + length;
116 for (int i = offset; i < end; i++)
117 appendByte(b[i]);
118 }
119 catch (IOException e)
120 {
121 throw new RuntimeException(e);
122 }
123 }
124
125 public boolean append(byte[] b, int offset, int length, int maxChars)
126 {
127 try
128 {
129 int end = offset + length;
130 for (int i = offset; i < end; i++)
131 {
132 if (length() > maxChars)
133 return false;
134 appendByte(b[i]);
135 }
136 return true;
137 }
138 catch (IOException e)
139 {
140 throw new RuntimeException(e);
141 }
142 }
143
144 protected void appendByte(byte b) throws IOException
145 {
146
147 if (b > 0 && _state == UTF8_ACCEPT)
148 {
149 _appendable.append((char)(b & 0xFF));
150 }
151 else
152 {
153 int i = b & 0xFF;
154 int type = BYTE_TABLE[i];
155 _codep = _state == UTF8_ACCEPT ? (0xFF >> type) & i : (i & 0x3F) | (_codep << 6);
156 int next = TRANS_TABLE[_state + type];
157
158 switch(next)
159 {
160 case UTF8_ACCEPT:
161 _state=next;
162 if (_codep < Character.MIN_HIGH_SURROGATE)
163 {
164 _appendable.append((char)_codep);
165 }
166 else
167 {
168 for (char c : Character.toChars(_codep))
169 _appendable.append(c);
170 }
171 break;
172
173 case UTF8_REJECT:
174 String reason = "byte "+TypeUtil.toHexString(b)+" in state "+(_state/12);
175 _codep=0;
176 _state = UTF8_ACCEPT;
177 _appendable.append(REPLACEMENT);
178 throw new NotUtf8Exception(reason);
179
180 default:
181 _state=next;
182
183 }
184 }
185 }
186
187 public boolean isUtf8SequenceComplete()
188 {
189 return _state == UTF8_ACCEPT;
190 }
191
192 public static class NotUtf8Exception extends IllegalArgumentException
193 {
194 public NotUtf8Exception(String reason)
195 {
196 super("Not valid UTF8! "+reason);
197 }
198 }
199
200 protected void checkState()
201 {
202 if (!isUtf8SequenceComplete())
203 {
204 _codep=0;
205 _state = UTF8_ACCEPT;
206 try
207 {
208 _appendable.append(REPLACEMENT);
209 }
210 catch(IOException e)
211 {
212 throw new RuntimeException(e);
213 }
214 throw new NotUtf8Exception("incomplete UTF8 sequence");
215 }
216 }
217
218 public String toReplacedString()
219 {
220 if (!isUtf8SequenceComplete())
221 {
222 _codep=0;
223 _state = UTF8_ACCEPT;
224 try
225 {
226 _appendable.append(REPLACEMENT);
227 }
228 catch(IOException e)
229 {
230 throw new RuntimeException(e);
231 }
232 Throwable th= new NotUtf8Exception("incomplete UTF8 sequence");
233 LOG.warn(th.toString());
234 LOG.debug(th);
235 }
236 return _appendable.toString();
237 }
238 }