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author | Luca Muscariello <lumuscar+fdio@cisco.com> | 2017-02-25 23:42:31 +0100 |
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committer | Luca Muscariello <lumuscar+fdio@cisco.com> | 2017-02-25 23:42:31 +0100 |
commit | 05c1a838c881ea502888659848d8792843b28718 (patch) | |
tree | cf0b05b58bd725a1eb6c80325ba986c63dea42aa /websocketpp/utf8_validator.hpp | |
parent | 9b30fc10fb1cbebe651e5a107e8ca5b24de54675 (diff) |
Initial commit: video player - viper
Change-Id: Id5aa33598ce34659bad4a7a9ae5006bfb84f9bd1
Signed-off-by: Luca Muscariello <lumuscar+fdio@cisco.com>
Diffstat (limited to 'websocketpp/utf8_validator.hpp')
-rw-r--r-- | websocketpp/utf8_validator.hpp | 154 |
1 files changed, 154 insertions, 0 deletions
diff --git a/websocketpp/utf8_validator.hpp b/websocketpp/utf8_validator.hpp new file mode 100644 index 00000000..c057da62 --- /dev/null +++ b/websocketpp/utf8_validator.hpp @@ -0,0 +1,154 @@ +/* + * The following code is adapted from code originally written by Bjoern + * Hoehrmann <bjoern@hoehrmann.de>. See + * http://bjoern.hoehrmann.de/utf-8/decoder/dfa/ for details. + * + * The original license: + * + * Copyright (c) 2008-2009 Bjoern Hoehrmann <bjoern@hoehrmann.de> + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS 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 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. +*/ + +#ifndef UTF8_VALIDATOR_HPP +#define UTF8_VALIDATOR_HPP + +#include <websocketpp/common/stdint.hpp> + +#include <string> + +namespace websocketpp { +namespace utf8_validator { + +/// State that represents a valid utf8 input sequence +static unsigned int const utf8_accept = 0; +/// State that represents an invalid utf8 input sequence +static unsigned int const utf8_reject = 1; + +/// Lookup table for the UTF8 decode state machine +static uint8_t const utf8d[] = { + 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 + 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 + 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 + 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 + 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 + 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 + 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 + 0xa,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x3,0x4,0x3,0x3, // e0..ef + 0xb,0x6,0x6,0x6,0x5,0x8,0x8,0x8,0x8,0x8,0x8,0x8,0x8,0x8,0x8,0x8, // f0..ff + 0x0,0x1,0x2,0x3,0x5,0x8,0x7,0x1,0x1,0x1,0x4,0x6,0x1,0x1,0x1,0x1, // s0..s0 + 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 + 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 + 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 + 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 +}; + +/// Decode the next byte of a UTF8 sequence +/** + * @param [out] state The decoder state to advance + * @param [out] codep The codepoint to fill in + * @param [in] byte The byte to input + * @return The ending state of the decode operation + */ +inline uint32_t decode(uint32_t * state, uint32_t * codep, uint8_t byte) { + uint32_t type = utf8d[byte]; + + *codep = (*state != utf8_accept) ? + (byte & 0x3fu) | (*codep << 6) : + (0xff >> type) & (byte); + + *state = utf8d[256 + *state*16 + type]; + return *state; +} + +/// Provides streaming UTF8 validation functionality +class validator { +public: + /// Construct and initialize the validator + validator() : m_state(utf8_accept),m_codepoint(0) {} + + /// Advance the state of the validator with the next input byte + /** + * @param byte The byte to advance the validation state with + * @return Whether or not the byte resulted in a validation error. + */ + bool consume (uint8_t byte) { + if (utf8_validator::decode(&m_state,&m_codepoint,byte) == utf8_reject) { + return false; + } + return true; + } + + /// Advance validator state with input from an iterator pair + /** + * @param begin Input iterator to the start of the input range + * @param end Input iterator to the end of the input range + * @return Whether or not decoding the bytes resulted in a validation error. + */ + template <typename iterator_type> + bool decode (iterator_type begin, iterator_type end) { + for (iterator_type it = begin; it != end; ++it) { + unsigned int result = utf8_validator::decode( + &m_state, + &m_codepoint, + static_cast<uint8_t>(*it) + ); + + if (result == utf8_reject) { + return false; + } + } + return true; + } + + /// Return whether the input sequence ended on a valid utf8 codepoint + /** + * @return Whether or not the input sequence ended on a valid codepoint. + */ + bool complete() { + return m_state == utf8_accept; + } + + /// Reset the validator to decode another message + void reset() { + m_state = utf8_accept; + m_codepoint = 0; + } +private: + uint32_t m_state; + uint32_t m_codepoint; +}; + +/// Validate a UTF8 string +/** + * convenience function that creates a validator, validates a complete string + * and returns the result. + */ +inline bool validate(std::string const & s) { + validator v; + if (!v.decode(s.begin(),s.end())) { + return false; + } + return v.complete(); +} + +} // namespace utf8_validator +} // namespace websocketpp + +#endif // UTF8_VALIDATOR_HPP |