1 /*
2 * Copyright 2012 The Netty Project
3 *
4 * The Netty Project licenses this file to you under the Apache License,
5 * version 2.0 (the "License"); you may not use this file except in compliance
6 * with the License. You may obtain a copy of the License at:
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
12 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
13 * License for the specific language governing permissions and limitations
14 * under the License.
15 */
16 /*
17 * Adaptation of http://bjoern.hoehrmann.de/utf-8/decoder/dfa/
18 *
19 * Copyright (c) 2008-2009 Bjoern Hoehrmann <bjoern@hoehrmann.de>
20 *
21 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software
22 * and associated documentation files (the "Software"), to deal in the Software without restriction,
23 * including without limitation the rights to use, copy, modify, merge, publish, distribute,
24 * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
25 * furnished to do so, subject to the following conditions:
26 *
27 * The above copyright notice and this permission notice shall be included in all copies or
28 * substantial portions of the Software.
29 *
30 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING
31 * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
32 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
33 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
34 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
35 */
36 package org.jboss.netty.handler.codec.http.websocketx;
37
38 import org.jboss.netty.handler.codec.frame.CorruptedFrameException;
39
40 /**
41 * Checks UTF8 bytes for validity before converting it into a string
42 */
43 final class Utf8Validator {
44 private static final int UTF8_ACCEPT = 0;
45 private static final int UTF8_REJECT = 12;
46
47 private static final byte[] TYPES = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
48 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,
49 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,
50 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,
51 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1,
52 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, 7, 7, 7, 7,
53 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, 8,
54 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,
55 2, 2, 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,
56 8, 8, 8, 8, 8, 8 };
57
58 private static final byte[] STATES = { 0, 12, 24, 36, 60, 96, 84, 12, 12, 12, 48, 72, 12, 12,
59 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 0, 12, 12, 12, 12, 12, 0, 12, 0, 12, 12,
60 12, 24, 12, 12, 12, 12, 12, 24, 12, 24, 12, 12, 12, 12, 12, 12, 12, 12, 12, 24, 12, 12,
61 12, 12, 12, 24, 12, 12, 12, 12, 12, 12, 12, 24, 12, 12, 12, 12, 12, 12, 12, 12, 12, 36,
62 12, 36, 12, 12, 12, 36, 12, 12, 12, 12, 12, 36, 12, 36, 12, 12, 12, 36, 12, 12, 12, 12,
63 12, 12, 12, 12, 12, 12 };
64
65 @SuppressWarnings("RedundantFieldInitialization")
66 private int state = UTF8_ACCEPT;
67 private int codep;
68 private boolean checking;
69
70 public void check(byte[] bytes) throws CorruptedFrameException {
71 checking = true;
72 for (byte b : bytes) {
73 write(b);
74 }
75 }
76
77 private void write(int b) throws CorruptedFrameException {
78 byte type = TYPES[b & 0xFF];
79
80 codep = state != UTF8_ACCEPT ? b & 0x3f | codep << 6 : 0xff >> type & b;
81
82 state = STATES[state + type];
83
84 if (state == UTF8_REJECT) {
85 throw new CorruptedFrameException("bytes are not UTF-8");
86 }
87 }
88
89 public void finish() throws CorruptedFrameException {
90 checking = false;
91 codep = 0;
92 if (state != UTF8_ACCEPT) {
93 state = UTF8_ACCEPT;
94 throw new CorruptedFrameException("bytes are not UTF-8");
95 }
96 }
97
98 public boolean isChecking() {
99 return checking;
100 }
101 }
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