NumberBase.hpp

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/*
 * libevdevxx - a C++ wrapper for libevdev
 *
 * Copyright (C) 2025  Daniel K. O.
 * SPDX-License-Identifier: MIT
 */
 
#ifndef LIBEVDEVXX_NUMBER_BASE_HPP
#define LIBEVDEVXX_NUMBER_BASE_HPP
 
#include <compare>
 
 
namespace evdev::detail {
 
    // this template uses CRTP to create a type-safe integer
 
 
    template<typename T,
             typename D>
    class NumberBase {
 
    protected:
 
        using Value = T;
        using Derived = D;
 
        Value value;
 
    public:
 
        constexpr
        NumberBase() noexcept :
            value{0}
        {}
 
 
        constexpr
        explicit
        NumberBase(Value value) noexcept :
            value{value}
        {}
 
 
        constexpr
        operator Value()
            const noexcept
        {
            return value;
        }
 
 
        // comparators
 
 
        constexpr
        bool
        operator ==(const NumberBase& other)
            const noexcept = default;
 
        constexpr
        std::strong_ordering
        operator <=>(const NumberBase& other)
            const noexcept = default;
 
 
        constexpr
        NumberBase&
        operator ++() noexcept
        {
            ++value;
            return *this;
        }
 
 
        constexpr
        Derived
        operator ++(int) noexcept
        {
            Derived old{*this};
            ++value;
            return old;
        }
 
    }; // class NumberBase
 
} // namespace evdev::detail
 
#endif