109 lines
2 KiB
C++
109 lines
2 KiB
C++
#include <psemek/util/unicode.hpp>
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#include <codecvt>
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#include <locale>
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namespace psemek::util
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{
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using converter = std::wstring_convert<std::codecvt_utf8<char32_t>, char32_t>;
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std::string to_utf8(std::u32string const & str)
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{
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return converter{}.to_bytes(str);
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}
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std::u32string from_utf8(std::string const & str)
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{
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return converter{}.from_bytes(str);
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}
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static bool is_1_byte(char c)
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{
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return (c & 0b10000000) == 0b00000000;
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}
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static bool is_2_byte(char c)
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{
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return (c & 0b11100000) == 0b11000000;
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}
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static bool is_3_byte(char c)
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{
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return (c & 0b11110000) == 0b11100000;
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}
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static bool is_4_byte(char c)
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{
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return (c & 0b11111000) == 0b11110000;
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}
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static bool is_middle_byte(char c)
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{
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return (c & 0b11000000) == 0b10000000;
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}
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static void assert_middle(char const * ptr)
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{
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#ifdef PSEMEK_DEBUG
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if (!is_middle_byte(*ptr))
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throw invalid_utf8(ptr);
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#else
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(void*)ptr;
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#endif
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}
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utf8_iterator & utf8_iterator::operator ++()
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{
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if (is_1_byte(ptr[0]))
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ptr += 1;
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else if (is_2_byte(ptr[0]))
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ptr += 2;
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else if (is_3_byte(ptr[0]))
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ptr += 3;
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else if (is_4_byte(ptr[0]))
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ptr += 4;
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return *this;
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}
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utf8_iterator utf8_iterator::operator ++(int)
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{
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utf8_iterator copy(*this);
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++(*this);
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return copy;
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}
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char32_t utf8_iterator::operator *() const
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{
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if (is_1_byte(ptr[0]))
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{
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return ptr[0];
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}
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else if (is_2_byte(ptr[0]))
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{
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assert_middle(ptr + 1);
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return (ptr[0] & 0b11111) | ((ptr[1] & 0b111111) << 5);
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}
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else if (is_3_byte(ptr[0]))
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{
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assert_middle(ptr + 1);
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assert_middle(ptr + 2);
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return (ptr[0] & 0b1111) | ((ptr[1] & 0b111111) << 4) | ((ptr[2] & 0b111111) << 10);
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}
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else if (is_4_byte(ptr[0]))
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{
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assert_middle(ptr + 1);
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assert_middle(ptr + 2);
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assert_middle(ptr + 3);
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return (ptr[0] & 0b111) | ((ptr[1] & 0b111111) << 3) | ((ptr[2] & 0b111111) << 9) | ((ptr[3] & 0b111111) << 15);
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}
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else
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throw invalid_utf8(ptr);
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}
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char const * invalid_utf8::what() const noexcept
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{
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return "Invalid UTF-8 string";
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}
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}
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