charconv.hpp

// Copyright Take Vos 2020-2022.
// 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 "../macros.hpp"
#include "terminate.hpp"
#include "exception.hpp"
#include <concepts>
#include <charconv>
#include <string>
#include <string_view>
#include <iterator>
 
hi_export_module(hikogui.utility.charconv);
 
hi_export namespace hi { inline namespace v1 {
 
template<std::integral T>
[[nodiscard]] std::string to_string(T const &value) noexcept
{
    std::array<char, 21> buffer;
 
    auto const first = buffer.data();
    auto const last = first + buffer.size();
 
    auto const[new_last, ec] = std::to_chars(first, last, value);
    hi_assert(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;
 
    auto const first = buffer.data();
    auto const last = first + buffer.size();
 
    auto const[new_last, ec] = std::to_chars(first, last, value, std::chars_format::general);
    hi_assert(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)
{
    auto value = T{};
 
    auto const first = str.data();
    auto const last = first + ssize(str);
 
    auto const[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;
 
    auto const first = str.data();
    auto const last = first + ssize(str);
 
    auto const[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 hi::inline v1