mp-units/example/include/ranged_representation.h

// The MIT License (MIT)
//
// Copyright (c) 2018 Mateusz Pusz
//
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#pragma once

#include "validated_type.h"
#include <mp-units/bits/external/hacks.h>
#include <mp-units/customization_points.h>
#include <algorithm>
#include <concepts>
#include <type_traits>

template<std::movable T, UNITS_CONSTRAINED_NTTP_WORKAROUND(std::convertible_to<T>) auto Min,
         UNITS_CONSTRAINED_NTTP_WORKAROUND(std::convertible_to<T>) auto Max>
inline constexpr auto is_in_range = [](const auto& v) { return std::clamp(v, T{Min}, T{Max}) == v; };

template<std::movable T, UNITS_CONSTRAINED_NTTP_WORKAROUND(std::convertible_to<T>) auto Min,
         UNITS_CONSTRAINED_NTTP_WORKAROUND(std::convertible_to<T>) auto Max>
using is_in_range_t = decltype(is_in_range<T, Min, Max>);

template<std::movable T, UNITS_CONSTRAINED_NTTP_WORKAROUND(std::convertible_to<T>) auto Min,
         UNITS_CONSTRAINED_NTTP_WORKAROUND(std::convertible_to<T>) auto Max>
class ranged_representation : public validated_type<T, is_in_range_t<T, Min, Max>> {
public:
  using validated_type<T, is_in_range_t<T, Min, Max>>::validated_type;
  constexpr ranged_representation() : validated_type<T, is_in_range_t<T, Min, Max>>(T{}) {}

  [[nodiscard]] constexpr ranged_representation operator-() const
    requires requires(T t) { -t; }
  {
    return ranged_representation(-this->value());
  }
};

template<typename T, auto Min, auto Max>
inline constexpr bool mp_units::is_scalar<ranged_representation<T, Min, Max>> = mp_units::is_scalar<T>;