basic_format_arg.hpp

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// SPDX-License-Identifier: BSL-1.0
// SPDX-FileCopyrightText: Copyright (C) 2023 Tobias Hienzsch
 
#ifndef TETL_FORMAT_BASIC_FORMAT_ARG_HPP
#define TETL_FORMAT_BASIC_FORMAT_ARG_HPP
 
#include <etl/_cstddef/nullptr_t.hpp>
#include <etl/_cstddef/size_t.hpp>
#include <etl/_format/basic_format_parse_context.hpp>
#include <etl/_string/basic_inplace_string.hpp>
#include <etl/_string_view/basic_string_view.hpp>
#include <etl/_utility/forward.hpp>
#include <etl/_variant/monostate.hpp>
#include <etl/_variant/variant.hpp>
namespace etl {
 
template <typename Context>
struct basic_format_arg;
 
namespace detail {
template <typename Context, typename T>
[[nodiscard]] constexpr auto make_arg(T&& value) -> basic_format_arg<Context>;
} // namespace detail
 
template <typename Context>
struct basic_format_arg {
private:
    using char_type = typename Context::char_type;
 
    template <typename ContextType, typename T>
    friend constexpr auto detail::make_arg(T&& value) -> basic_format_arg<ContextType>;
 
public:
    struct handle {
        auto format(basic_format_parse_context<char_type>&, Context& ctx) const -> void;
 
    private:
        friend struct basic_format_arg<Context>;
 
        template <typename T>
        explicit handle(T&& val) noexcept;
 
        void const* _ptr;
        void (*_format)(basic_format_parse_context<char_type>&, Context&, void const*);
    };
 
    basic_format_arg() noexcept = default;
 
    explicit operator bool() const noexcept
    {
        return holds_alternative<monostate>(value);
    }
 
    template <typename T>
    explicit basic_format_arg(T&& v) noexcept;
    explicit basic_format_arg(float n) noexcept;
    explicit basic_format_arg(double n) noexcept;
    explicit basic_format_arg(long double n) noexcept;
    explicit basic_format_arg(char_type const* s);
 
    template <typename Traits>
    explicit basic_format_arg(basic_string_view<char_type, Traits> s) noexcept;
 
    template <etl::size_t Capacity, typename Traits>
    explicit basic_format_arg(basic_inplace_string<char_type, Capacity, Traits> const& s) noexcept;
 
    explicit basic_format_arg(nullptr_t) noexcept;
 
    template <typename T>
    explicit basic_format_arg(T* p) noexcept;
 
    variant<                          // variant<                         //        monostate,                    //
        bool,                         //
        char_type,                    //
        int,                          //
        unsigned int,                 //
        long long int,                //
        unsigned long long int,       //
        float,                        //
        double,                       //
        long double,                  //
        char_type const*,             //
        basic_string_view<char_type>, //
        void const*,                  //
        handle                        //
        >
        value{monostate{}};
};
 
namespace detail {
template <typename Context, typename T>
[[nodiscard]] constexpr auto make_arg(T&& value) -> basic_format_arg<Context>
{
    return {etl::forward<T>(value)};
}
} // namespace detail
 
} // namespace etl
 
#endif // TETL_FORMAT_BASIC_FORMAT_ARG_HPP