2 * The following code is adapted from code originally written by Bjoern
3 * Hoehrmann <bjoern@hoehrmann.de>. See
4 * http://bjoern.hoehrmann.de/utf-8/decoder/dfa/ for details.
6 * The original license:
8 * Copyright (c) 2008-2009 Bjoern Hoehrmann <bjoern@hoehrmann.de>
10 * Permission is hereby granted, free of charge, to any person obtaining a copy
11 * of this software and associated documentation files (the "Software"), to deal
12 * in the Software without restriction, including without limitation the rights
13 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
14 * copies of the Software, and to permit persons to whom the Software is
15 * furnished to do so, subject to the following conditions:
17 * The above copyright notice and this permission notice shall be included in
18 * all copies or substantial portions of the Software.
20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
21 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
23 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
24 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
25 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
29 #ifndef UTF8_VALIDATOR_HPP
30 #define UTF8_VALIDATOR_HPP
32 #include <websocketpp/common/stdint.hpp>
36 namespace websocketpp {
37 namespace utf8_validator {
39 /// State that represents a valid utf8 input sequence
40 static unsigned int const utf8_accept = 0;
41 /// State that represents an invalid utf8 input sequence
42 static unsigned int const utf8_reject = 1;
44 /// Lookup table for the UTF8 decode state machine
45 static uint8_t const utf8d[] = {
46 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, // 00..1f
47 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, // 20..3f
48 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 40..5f
49 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, // 60..7f
50 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, // 80..9f
51 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, // a0..bf
52 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, // c0..df
53 0xa,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x4,0x3,0x3, // e0..ef
54 0xb,0x6,0x6,0x6,0x5,0x8,0x8,0x8,0x8,0x8,0x8,0x8,0x8,0x8,0x8,0x8, // f0..ff
55 0x0,0x1,0x2,0x3,0x5,0x8,0x7,0x1,0x1,0x1,0x4,0x6,0x1,0x1,0x1,0x1, // s0..s0
56 1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,0,1,0,1,1,1,1,1,1, // s1..s2
57 1,2,1,1,1,1,1,2,1,2,1,1,1,1,1,1,1,1,1,1,1,1,1,2,1,1,1,1,1,1,1,1, // s3..s4
58 1,2,1,1,1,1,1,1,1,2,1,1,1,1,1,1,1,1,1,1,1,1,1,3,1,3,1,1,1,1,1,1, // s5..s6
59 1,3,1,1,1,1,1,3,1,3,1,1,1,1,1,1,1,3,1,1,1,1,1,1,1,1,1,1,1,1,1,1, // s7..s8
62 /// Decode the next byte of a UTF8 sequence
64 * @param [out] state The decoder state to advance
65 * @param [out] codep The codepoint to fill in
66 * @param [in] byte The byte to input
67 * @return The ending state of the decode operation
69 inline uint32_t decode(uint32_t * state, uint32_t * codep, uint8_t byte) {
70 uint32_t type = utf8d[byte];
72 *codep = (*state != utf8_accept) ?
73 (byte & 0x3fu) | (*codep << 6) :
74 (0xff >> type) & (byte);
76 *state = utf8d[256 + *state*16 + type];
80 /// Provides streaming UTF8 validation functionality
83 /// Construct and initialize the validator
84 validator() : m_state(utf8_accept),m_codepoint(0) {}
86 /// Advance the state of the validator with the next input byte
88 * @param byte The byte to advance the validation state with
89 * @return Whether or not the byte resulted in a validation error.
91 bool consume (uint8_t byte) {
92 if (utf8_validator::decode(&m_state,&m_codepoint,byte) == utf8_reject) {
98 /// Advance validator state with input from an iterator pair
100 * @param begin Input iterator to the start of the input range
101 * @param end Input iterator to the end of the input range
102 * @return Whether or not decoding the bytes resulted in a validation error.
104 template <typename iterator_type>
105 bool decode (iterator_type begin, iterator_type end) {
106 for (iterator_type it = begin; it != end; ++it) {
107 unsigned int result = utf8_validator::decode(
110 static_cast<uint8_t>(*it)
113 if (result == utf8_reject) {
120 /// Return whether the input sequence ended on a valid utf8 codepoint
122 * @return Whether or not the input sequence ended on a valid codepoint.
125 return m_state == utf8_accept;
128 /// Reset the validator to decode another message
130 m_state = utf8_accept;
135 uint32_t m_codepoint;
138 /// Validate a UTF8 string
140 * convenience function that creates a validator, validates a complete string
141 * and returns the result.
143 inline bool validate(std::string const & s) {
145 if (!v.decode(s.begin(),s.end())) {
151 } // namespace utf8_validator
152 } // namespace websocketpp
154 #endif // UTF8_VALIDATOR_HPP