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Remove std::from_chars from extract.hpp

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This commit is contained in:
ado 2023-08-04 22:31:29 +02:00
parent 634abdd38b
commit 81484f737f
1 changed files with 25 additions and 4 deletions
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29
include/ss/extract.hpp
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@ -12,7 +12,8 @@
#ifndef SSP_DISABLE_FAST_FLOAT
#include <fast_float/fast_float.h>
#else
#include <charconv>
#include <algorithm>
#include <cstdlib>
#endif
namespace ss {
@ -40,12 +41,32 @@ std::enable_if_t<std::is_floating_point_v<T>, std::optional<T>> to_num(
template <typename T>
std::enable_if_t<std::is_floating_point_v<T>, std::optional<T>> to_num(
const char* const begin, const char* const end) {
T ret;
auto [ptr, ec] = std::from_chars(begin, end, ret);
constexpr static auto buff_max = 64;
char buff[buff_max];
size_t string_range = std::distance(begin, end);
if (ec != std::errc() || ptr != end) {
if (string_range > buff_max) {
return std::nullopt;
}
std::copy_n(begin, string_range, buff);
buff[string_range] = '\0';
T ret;
char* parse_end = nullptr;
if constexpr (std::is_same_v<T, float>) {
ret = std::strtof(buff, &parse_end);
} else if constexpr (std::is_same_v<T, double>) {
ret = std::strtod(buff, &parse_end);
} else if constexpr (std::is_same_v<T, long double>) {
ret = std::strtold(buff, &parse_end);
}
if (parse_end != buff + string_range) {
return std::nullopt;
}
return ret;
}