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/*
* 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. */
/*
* IXUtf8Validator.h * Author: Benjamin Sergeant * Copyright (c) 2019 Machine Zone, Inc. All rights reserved. * * From websocketpp. Tiny modifications made for code style, function names etc... */
#pragma once
#include <cstdint>
#include <string>
namespace ix{ /// 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 decodeNextByte(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 Utf8Validator { public: /// Construct and initialize the validator
Utf8Validator() : 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 (decodeNextByte(&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 = decodeNextByte(&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 validateUtf8(std::string const& s) { Utf8Validator v; if (!v.decode(s.begin(), s.end())) { return false; } return v.complete(); }
} // namespace ix
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