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#pragma once
#include <locale>
#include <string>
#include <algorithm>
#include "../errors.h"
namespace sqlite {
namespace utility {
inline std::string utf16_to_utf8(u16str_ref input) {
struct : std::codecvt<char16_t, char, std::mbstate_t> {
} codecvt;
std::mbstate_t state{};
std::string result((std::max)(input.size() * 3 / 2, std::size_t(4)), '\0');
const char16_t *remaining_input = input.data();
std::size_t produced_output = 0;
while(true) {
char *used_output;
switch(codecvt.out(state, remaining_input, input.data() + input.size(),
remaining_input, &result[produced_output],
&result[result.size() - 1] + 1, used_output)) {
case std::codecvt_base::ok:
result.resize(used_output - result.data());
return result;
case std::codecvt_base::noconv:
// This should be unreachable
case std::codecvt_base::error:
throw errors::invalid_utf16("Invalid UTF-16 input", "");
case std::codecvt_base::partial:
if(used_output == result.data() + produced_output)
throw errors::invalid_utf16("Unexpected end of input", "");
produced_output = used_output - result.data();
result.resize(
result.size()
+ (std::max)((input.data() + input.size() - remaining_input) * 3 / 2,
std::ptrdiff_t(4)));
}
}
}
} // namespace utility
} // namespace sqlite
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