charconv.hpp

// Copyright Take Vos 2020.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt)
 
#pragma once
 
#include <concepts>
#include <charconv>
 
namespace tt {
 
template<std::integral T>
[[nodiscard]] std::string to_string(T const &value) noexcept
{
    std::array<char, 21> buffer;
 
    ttlet first = buffer.data();
    ttlet last = first + std::size(buffer);
 
    ttlet[new_last, ec] = std::to_chars(first, last, value);
    tt_axiom(ec == std::errc{});
 
    auto r = std::string{};
    std::copy(first, new_last, std::back_inserter(r));
    return r;
}
 
template<std::floating_point T>
[[nodiscard]] std::string to_string(T const &value) noexcept
{
    std::array<char, 128> buffer;
 
    ttlet first = buffer.data();
    ttlet last = first + std::size(buffer);
 
    ttlet[new_last, ec] = std::to_chars(first, last, value, std::chars_format::general);
    tt_axiom(ec == std::errc{});
 
    auto r = std::string{};
    std::copy(first, new_last, std::back_inserter(r));
    return r;
}
 
template<std::integral T>
[[nodiscard]] T from_string(std::string_view str, int base = 10)
{
    T value;
 
    ttlet first = str.data();
    ttlet last = first + std::ssize(str);
 
    ttlet[new_last, ec] = std::from_chars(first, last, value, base);
    if (ec != std::errc{} or new_last != last) {
        throw parse_error("Can not convert string to integer");
    }
 
    return value;
}
 
template<std::floating_point T>
[[nodiscard]] T from_string(std::string_view str)
{
    T value;
 
    ttlet first = str.data();
    ttlet last = first + std::ssize(str);
 
    ttlet[new_last, ec] = std::from_chars(first, last, value);
    if (ec != std::errc{} or new_last != last) {
        throw parse_error("Can not convert string to floating point");
    }
 
    return value;
}
 
} // namespace tt