69 lines
1.6 KiB
C++
69 lines
1.6 KiB
C++
#ifndef _library__utf8__hpp__included__
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#define _library__utf8__hpp__included__
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#include <iostream>
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#include <cstdint>
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#include <cstdlib>
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#include <string>
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#include <functional>
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/**
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* Initial state for UTF-8 parser.
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*/
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extern const uint16_t utf8_initial_state;
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/**
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* Parse a byte.
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*
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* Parameter ch: The character to parse. -1 for end of string.
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* Parameter state: The state. Mutated.
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* Returns: The codepoint, or -1 if no codepoint emitted.
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*
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* Note: When called with EOF, max 1 codepoint can be emitted.
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*/
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int32_t utf8_parse_byte(int ch, uint16_t& state) throw();
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/**
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* Return length of string in UTF-8 codepoints.
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*
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* Parameter str: The string.
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* Returns: The length in codepoints.
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*/
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size_t utf8_strlen(const std::string& str) throw();
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/**
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* Transform UTF-8 into UTF-32.
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*/
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std::u32string to_u32string(const std::string& utf8);
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/**
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* Transform UTF-32 into UTF-8.
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*/
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std::string to_u8string(const std::u32string& utf32);
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/**
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* Iterator to function copy from UTF-8 to UTF-32
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*/
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template<typename srcitr>
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inline void copy_from_utf8_2(srcitr begin, srcitr end, std::function<void(int32_t)> target)
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{
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uint16_t state = utf8_initial_state;
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for(srcitr i = begin; i != end; i++) {
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int32_t x = utf8_parse_byte((unsigned char)*i, state);
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if(x >= 0)
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target(x);
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}
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int32_t x = utf8_parse_byte(-1, state);
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if(x >= 0)
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target(x);
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}
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/**
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* Iterator copy from UTF-8 to UTF-32
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*/
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template<typename srcitr, typename dstitr>
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inline void copy_from_utf8(srcitr begin, srcitr end, dstitr target)
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{
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copy_from_utf8_2(begin, end, [&target](int32_t x) { *target = x; ++target; });
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}
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#endif
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