43 lines
1.4 KiB
C++
43 lines
1.4 KiB
C++
#pragma once
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#include <locale>
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#include <string>
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#include <algorithm>
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#include "../errors.h"
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namespace sqlite {
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namespace utility {
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inline std::string utf16_to_utf8(const std::u16string &input) {
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struct : std::codecvt<char16_t, char, std::mbstate_t> {
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} codecvt;
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std::mbstate_t state{};
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std::string result((std::max)(input.size() * 3 / 2, std::size_t(4)), '\0');
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const char16_t *remaining_input = input.data();
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std::size_t produced_output = 0;
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while(true) {
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char *used_output;
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switch(codecvt.out(state, remaining_input, &input[input.size()],
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remaining_input, &result[produced_output],
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&result[result.size() - 1] + 1, used_output)) {
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case std::codecvt_base::ok:
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result.resize(used_output - result.data());
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return result;
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case std::codecvt_base::noconv:
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// This should be unreachable
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case std::codecvt_base::error:
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throw errors::invalid_utf16("Invalid UTF-16 input", "");
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case std::codecvt_base::partial:
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if(used_output == result.data() + produced_output)
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throw errors::invalid_utf16("Unexpected end of input", "");
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produced_output = used_output - result.data();
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result.resize(
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result.size()
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+ (std::max)((&input[input.size()] - remaining_input) * 3 / 2,
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std::ptrdiff_t(4)));
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}
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}
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}
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} // namespace utility
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} // namespace sqlite
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