kopia lustrzana https://github.com/jameshball/osci-render
179 wiersze
7.1 KiB
C++
179 wiersze
7.1 KiB
C++
/*
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* The following code is adapted from code originally written by Bjoern
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* Hoehrmann <bjoern@hoehrmann.de>. See
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* http://bjoern.hoehrmann.de/utf-8/decoder/dfa/ for details.
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*
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* The original license:
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*
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* Copyright (c) 2008-2009 Bjoern Hoehrmann <bjoern@hoehrmann.de>
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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/*
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* IXUtf8Validator.h
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* Author: Benjamin Sergeant
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* Copyright (c) 2019 Machine Zone, Inc. All rights reserved.
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*
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* From websocketpp. Tiny modifications made for code style, function names etc...
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*/
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#pragma once
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#include <cstdint>
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#include <string>
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namespace ix
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{
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/// State that represents a valid utf8 input sequence
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static unsigned int const utf8_accept = 0;
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/// State that represents an invalid utf8 input sequence
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static unsigned int const utf8_reject = 1;
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/// Lookup table for the UTF8 decode state machine
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static uint8_t const utf8d[] = {
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 00..1f
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 20..3f
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 40..5f
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, // 60..7f
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1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
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9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, // 80..9f
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7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
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7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, // a0..bf
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8, 8, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
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2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, // c0..df
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0xa, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x4, 0x3, 0x3, // e0..ef
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0xb, 0x6, 0x6, 0x6, 0x5, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, // f0..ff
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0x0, 0x1, 0x2, 0x3, 0x5, 0x8, 0x7, 0x1, 0x1, 0x1, 0x4, 0x6, 0x1, 0x1, 0x1, 0x1, // s0..s0
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1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
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1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, // s1..s2
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1, 2, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 1, 1, 1,
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1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, // s3..s4
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1, 2, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1,
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1, 1, 1, 1, 1, 1, 1, 3, 1, 3, 1, 1, 1, 1, 1, 1, // s5..s6
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1, 3, 1, 1, 1, 1, 1, 3, 1, 3, 1, 1, 1, 1, 1, 1,
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1, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // s7..s8
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};
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/// Decode the next byte of a UTF8 sequence
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/**
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* @param [out] state The decoder state to advance
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* @param [out] codep The codepoint to fill in
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* @param [in] byte The byte to input
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* @return The ending state of the decode operation
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*/
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inline uint32_t decodeNextByte(uint32_t* state, uint32_t* codep, uint8_t byte)
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{
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uint32_t type = utf8d[byte];
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*codep = (*state != utf8_accept) ? (byte & 0x3fu) | (*codep << 6) : (0xff >> type) & (byte);
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*state = utf8d[256 + *state * 16 + type];
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return *state;
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}
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/// Provides streaming UTF8 validation functionality
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class Utf8Validator
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{
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public:
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/// Construct and initialize the validator
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Utf8Validator()
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: m_state(utf8_accept)
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, m_codepoint(0)
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{
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}
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/// Advance the state of the validator with the next input byte
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/**
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* @param byte The byte to advance the validation state with
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* @return Whether or not the byte resulted in a validation error.
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*/
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bool consume(uint8_t byte)
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{
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if (decodeNextByte(&m_state, &m_codepoint, byte) == utf8_reject)
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{
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return false;
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}
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return true;
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}
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/// Advance Validator state with input from an iterator pair
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/**
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* @param begin Input iterator to the start of the input range
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* @param end Input iterator to the end of the input range
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* @return Whether or not decoding the bytes resulted in a validation error.
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*/
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template<typename iterator_type>
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bool decode(iterator_type begin, iterator_type end)
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{
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for (iterator_type it = begin; it != end; ++it)
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{
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unsigned int result =
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decodeNextByte(&m_state, &m_codepoint, static_cast<uint8_t>(*it));
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if (result == utf8_reject)
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{
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return false;
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}
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}
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return true;
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}
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/// Return whether the input sequence ended on a valid utf8 codepoint
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/**
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* @return Whether or not the input sequence ended on a valid codepoint.
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*/
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bool complete()
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{
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return m_state == utf8_accept;
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}
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/// Reset the Validator to decode another message
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void reset()
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{
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m_state = utf8_accept;
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m_codepoint = 0;
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}
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private:
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uint32_t m_state;
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uint32_t m_codepoint;
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};
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/// Validate a UTF8 string
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/**
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* convenience function that creates a Validator, validates a complete string
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* and returns the result.
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*/
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inline bool validateUtf8(std::string const& s)
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{
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Utf8Validator v;
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if (!v.decode(s.begin(), s.end()))
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{
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return false;
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}
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return v.complete();
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}
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} // namespace ix
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