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mp-units/src/core/include/units/quantity.h
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2022-08-01 10:03:55 +02:00

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// The MIT License (MIT)
//
// Copyright (c) 2018 Mateusz Pusz
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
#pragma once
#include <units/bits/common_type.h>
#include <units/generic/dimensionless.h>
// IWYU pragma: begin_exports
#include <units/quantity_cast.h>
#include <units/ratio.h>
#include <compare>
// IWYU pragma: end_exports
#include <units/reference.h>
#include <utility>
namespace units {
namespace detail {
template<Reference auto R> // TODO: Replace with `v * R` pending https://github.com/BobSteagall/wg21/issues/58.
inline constexpr auto make_quantity = [](auto&& v) {
using Rep = std::remove_cvref_t<decltype(v)>;
return quantity<typename decltype(R)::dimension, typename decltype(R)::unit, Rep>(std::forward<decltype(v)>(v));
};
template<typename T>
concept quantity_one =
Quantity<T> &&
(std::same_as<typename T::dimension, dim_one> || std::same_as<typename T::dimension, unknown_dimension<>>) &&
detail::equivalent_unit<typename T::unit, typename T::dimension, ::units::one, typename T::dimension>::value;
} // namespace detail
template<typename T>
concept floating_point_ = // exposition only
(Quantity<T> && treat_as_floating_point<typename T::rep>) || (!Quantity<T> && treat_as_floating_point<T>);
template<typename From, typename To>
concept safe_convertible_to_ = // exposition only
(!Quantity<From>) && (!Quantity<To>) && std::convertible_to<From, To> &&
(floating_point_<To> || (!floating_point_<From>));
// QFrom ratio is an exact multiple of QTo
template<typename QFrom, typename QTo>
concept harmonic_ = // exposition only
Quantity<QFrom> && Quantity<QTo> && is_integral(detail::quantity_ratio<QFrom> / detail::quantity_ratio<QTo>);
template<typename QFrom, typename QTo>
concept safe_castable_to_ = // exposition only
Quantity<QFrom> && QuantityOf<QTo, typename QFrom::dimension> &&
scalable_with_<typename QFrom::rep, typename QTo::rep> &&
(floating_point_<QTo> || (!floating_point_<QFrom> && harmonic_<QFrom, QTo>));
template<typename Func, typename T, typename U>
concept quantity_value_for_ = std::regular_invocable<Func, T, U> && Representation<std::invoke_result_t<Func, T, U>>;
template<typename T, typename Func, typename U, typename V>
concept invoke_result_convertible_to_ =
Representation<T> && quantity_value_for_<Func, U, V> && safe_convertible_to_<T, std::invoke_result_t<Func, U, V>>;
template<typename Func, typename Q, typename V>
concept have_quantity_for_ = Quantity<Q> && (!Quantity<V>) && quantity_value_for_<Func, typename Q::rep, V>;
template<QuantityLike Q>
using quantity_like_type = quantity<typename quantity_like_traits<Q>::dimension, typename quantity_like_traits<Q>::unit,
typename quantity_like_traits<Q>::rep>;
/**
* @brief A quantity
*
* Property of a phenomenon, body, or substance, where the property has a magnitude that can be
* expressed by means of a number and a measurement unit.
*
* @tparam D a dimension of the quantity (can be either a BaseDimension or a DerivedDimension)
* @tparam U a measurement unit of the quantity
* @tparam Rep a type to be used to represent values of a quantity
*/
template<Dimension D, UnitOf<D> U, Representation Rep = double>
class quantity {
Rep number_;
public:
// member types and values
using dimension = D;
using unit = U;
using rep = Rep;
static constexpr units::reference<dimension, unit> reference{};
// static member functions
[[nodiscard]] static constexpr quantity zero() noexcept
requires requires { quantity_values<rep>::zero(); }
{
return quantity(quantity_values<rep>::zero());
}
[[nodiscard]] static constexpr quantity one() noexcept
requires requires { quantity_values<rep>::one(); }
{
return quantity(quantity_values<rep>::one());
}
[[nodiscard]] static constexpr quantity min() noexcept
requires requires { quantity_values<rep>::min(); }
{
return quantity(quantity_values<rep>::min());
}
[[nodiscard]] static constexpr quantity max() noexcept
requires requires { quantity_values<rep>::max(); }
{
return quantity(quantity_values<rep>::max());
}
// construction, assignment, destruction
quantity() = default;
quantity(const quantity&) = default;
quantity(quantity&&) = default;
template<typename Value>
requires(safe_convertible_to_<std::remove_cvref_t<Value>, rep>)
constexpr explicit(!detail::quantity_one<quantity>) quantity(Value&& v) : number_(std::forward<Value>(v))
{
}
template<safe_castable_to_<quantity> Q>
constexpr explicit(false) quantity(const Q& q) : number_(quantity_cast<quantity>(q).number())
{
}
template<QuantityLike Q>
requires(safe_castable_to_<quantity_like_type<Q>, quantity>)
constexpr explicit quantity(const Q& q) : quantity(quantity_like_type<Q>(quantity_like_traits<Q>::number(q)))
{
}
quantity& operator=(const quantity&) = default;
quantity& operator=(quantity&&) = default;
// data access
[[nodiscard]] constexpr rep& number() & noexcept { return number_; }
[[nodiscard]] constexpr const rep& number() const& noexcept { return number_; }
[[nodiscard]] constexpr rep&& number() && noexcept { return std::move(number_); }
[[nodiscard]] constexpr const rep&& number() const&& noexcept { return std::move(number_); }
// member unary operators
[[nodiscard]] constexpr Quantity auto operator+() const
requires requires(rep v) {
{
+v
} -> std::common_with<rep>;
}
{
using ret = quantity<D, U, decltype(+number())>;
return ret(+number());
}
[[nodiscard]] constexpr Quantity auto operator-() const
requires(std::regular_invocable<std::negate<>, rep>)
{
using ret = quantity<D, U, decltype(-number())>;
return ret(-number());
}
constexpr quantity& operator++()
requires requires(rep v) {
{
++v
} -> std::same_as<rep&>;
}
{
++number_;
return *this;
}
[[nodiscard]] constexpr quantity operator++(int)
requires requires(rep v) {
{
v++
} -> std::same_as<rep>;
}
{
return quantity(number_++);
}
constexpr quantity& operator--()
requires requires(rep v) {
{
--v
} -> std::same_as<rep&>;
}
{
--number_;
return *this;
}
[[nodiscard]] constexpr quantity operator--(int)
requires requires(rep v) {
{
v--
} -> std::same_as<rep>;
}
{
return quantity(number_--);
}
constexpr quantity& operator+=(const quantity& q)
requires requires(rep a, rep b) {
{
a += b
} -> std::same_as<rep&>;
}
{
number_ += q.number();
return *this;
}
constexpr quantity& operator-=(const quantity& q)
requires requires(rep a, rep b) {
{
a -= b
} -> std::same_as<rep&>;
}
{
number_ -= q.number();
return *this;
}
template<typename Rep2>
constexpr quantity& operator*=(const Rep2& rhs)
requires requires(rep a, const Rep2 b) {
{
a *= b
} -> std::same_as<rep&>;
}
{
number_ *= rhs;
return *this;
}
template<detail::quantity_one Q>
constexpr quantity& operator*=(const Q& rhs)
requires requires(rep a, const typename Q::rep b) {
{
a *= b
} -> std::same_as<rep&>;
}
{
number_ *= rhs.number();
return *this;
}
template<typename Rep2>
constexpr quantity& operator/=(const Rep2& rhs)
requires requires(rep a, const Rep2 b) {
{
a /= b
} -> std::same_as<rep&>;
}
{
gsl_ExpectsAudit(rhs != quantity_values<Rep2>::zero());
number_ /= rhs;
return *this;
}
template<detail::quantity_one Q>
constexpr quantity& operator/=(const Q& rhs)
requires requires(rep a, const typename Q::rep b) {
{
a /= b
} -> std::same_as<rep&>;
}
{
gsl_ExpectsAudit(rhs.number() != quantity_values<typename Q::rep>::zero());
number_ /= rhs.number();
return *this;
}
template<typename Rep2>
constexpr quantity& operator%=(const Rep2& rhs)
requires(!floating_point_<rep>) && (!floating_point_<Rep2>) && requires(rep a, const Rep2 b) {
{
a %= b
} -> std::same_as<rep&>;
}
{
gsl_ExpectsAudit(rhs != quantity_values<Rep2>::zero());
number_ %= rhs;
return *this;
}
template<detail::quantity_one Q>
constexpr quantity& operator%=(const Q& rhs)
requires(!floating_point_<rep>) && (!floating_point_<typename Q::rep>) && requires(rep a, const typename Q::rep b) {
{
a %= b
} -> std::same_as<rep&>;
}
{
gsl_ExpectsAudit(rhs.number() != quantity_values<typename Q::rep>::zero());
number_ %= rhs.number();
return *this;
}
constexpr quantity& operator%=(const quantity& q)
requires(!floating_point_<rep>) && requires(rep a, rep b) {
{
a %= b
} -> std::same_as<rep&>;
}
{
gsl_ExpectsAudit(q.number() != quantity_values<rep>::zero());
number_ %= q.number();
return *this;
}
// Hidden Friends
// Below friend functions are to be found via argument-dependent lookup only
template<typename Value>
[[nodiscard]] friend constexpr Quantity auto operator+(const quantity& lhs, const Value& rhs)
requires requires { // TODO: Simplify when Clang catches up.
requires !Quantity<Value>;
requires is_same_v<unit, units::one>;
requires invoke_result_convertible_to_<rep, std::plus<>, rep, Value>;
}
{
return units::quantity(lhs.number() + rhs);
}
template<typename Value>
[[nodiscard]] friend constexpr Quantity auto operator+(const Value& lhs, const quantity& rhs)
requires requires { // TODO: Simplify when Clang catches up.
requires !Quantity<Value>;
requires is_same_v<unit, units::one>;
requires invoke_result_convertible_to_<rep, std::plus<>, Value, rep>;
}
{
return units::quantity(lhs + rhs.number());
}
template<typename Value>
[[nodiscard]] friend constexpr Quantity auto operator-(const quantity& lhs, const Value& rhs)
requires requires { // TODO: Simplify when Clang catches up.
requires !Quantity<Value>;
requires is_same_v<unit, units::one>;
requires invoke_result_convertible_to_<rep, std::minus<>, rep, Value>;
}
{
return units::quantity(lhs.number() - rhs);
}
template<typename Value>
[[nodiscard]] friend constexpr Quantity auto operator-(const Value& lhs, const quantity& rhs)
requires requires { // TODO: Simplify when Clang catches up.
requires !Quantity<Value>;
requires is_same_v<unit, units::one>;
requires invoke_result_convertible_to_<rep, std::minus<>, Value, rep>;
}
{
return units::quantity(lhs - rhs.number());
}
template<Representation Value>
requires(invoke_result_convertible_to_<rep, std::multiplies<>, rep, const Value&>)
[[nodiscard]] friend constexpr Quantity auto operator*(const quantity& q, const Value& v)
{
using ret = quantity<D, U, std::invoke_result_t<std::multiplies<>, rep, Value>>;
return ret(q.number() * v);
}
template<Representation Value>
requires(invoke_result_convertible_to_<rep, std::multiplies<>, const Value&, rep>)
[[nodiscard]] friend constexpr Quantity auto operator*(const Value& v, const quantity& q)
{
using ret = quantity<D, U, std::invoke_result_t<std::multiplies<>, Value, rep>>;
return ret(v * q.number());
}
template<typename Value>
requires(!Quantity<Value>) && (invoke_result_convertible_to_<rep, std::divides<>, rep, const Value&>)
[[nodiscard]] friend constexpr Quantity auto operator/(const quantity& q, const Value& v)
{
gsl_ExpectsAudit(v != quantity_values<Value>::zero());
using ret = quantity<D, U, std::invoke_result_t<std::divides<>, rep, Value>>;
return ret(q.number() / v);
}
template<typename Value>
requires(!Quantity<Value>) && (invoke_result_convertible_to_<rep, std::divides<>, const Value&, rep>)
[[nodiscard]] friend constexpr Quantity auto operator/(const Value& v, const quantity& q)
{
return detail::make_quantity<::units::reference<dim_one, ::units::one>{} / reference>(v / q.number());
}
template<typename Value>
requires(!Quantity<Value>) && (!floating_point_<rep>) && (!floating_point_<Value>) &&
(invoke_result_convertible_to_<rep, std::modulus<>, rep, const Value&>)
[[nodiscard]] friend constexpr Quantity auto operator%(const quantity& q, const Value& v)
{
gsl_ExpectsAudit(v != quantity_values<Value>::zero());
using ret = quantity<D, U, std::invoke_result_t<std::modulus<>, rep, Value>>;
return ret(q.number() % v);
}
[[nodiscard]] friend constexpr Quantity auto operator%(const quantity& lhs, const quantity& rhs)
requires(!floating_point_<rep>) && (invoke_result_convertible_to_<rep, std::modulus<>, rep, rep>)
{
gsl_ExpectsAudit(rhs.number() != quantity_values<rep>::zero());
using ret = quantity<D, U, std::invoke_result_t<std::modulus<>, rep, rep>>;
return ret(lhs.number() % rhs.number());
}
[[nodiscard]] friend constexpr auto operator<=>(const quantity& lhs, const quantity& rhs)
requires std::three_way_comparable<rep>
#if UNITS_COMP_GCC == 10 && UNITS_COMP_GCC_MINOR >= 2
= default;
#else
{
return lhs.number() <=> rhs.number();
}
#endif
[[nodiscard]] friend constexpr bool operator==(const quantity& lhs, const quantity& rhs) = default;
};
// CTAD
#if !UNITS_COMP_CLANG || UNITS_COMP_CLANG > 16
template<typename D, typename U, typename Rep>
explicit(false) quantity(Rep&&)->quantity<D, U, Rep>;
#endif
template<typename D, typename U, typename Rep>
explicit(false) quantity(quantity<D, U, Rep>)->quantity<D, U, Rep>;
template<Representation Rep>
explicit(false) quantity(Rep)->quantity<dim_one, one, Rep>;
template<QuantityLike Q>
explicit quantity(Q) -> quantity<typename quantity_like_traits<Q>::dimension, typename quantity_like_traits<Q>::unit,
typename quantity_like_traits<Q>::rep>;
// non-member binary operators
template<Quantity Q1, QuantityEquivalentTo<Q1> Q2>
requires(quantity_value_for_<std::plus<>, typename Q1::rep, typename Q2::rep>)
[[nodiscard]] constexpr Quantity auto operator+(const Q1& lhs, const Q2& rhs)
{
using ref = detail::common_quantity_reference<Q1, Q2>;
using ret = quantity<typename ref::dimension, typename ref::unit, decltype(lhs.number() + rhs.number())>;
return ret(ret(lhs).number() + ret(rhs).number());
}
template<Quantity Q1, QuantityEquivalentTo<Q1> Q2>
requires(quantity_value_for_<std::minus<>, typename Q1::rep, typename Q2::rep>)
[[nodiscard]] constexpr Quantity auto operator-(const Q1& lhs, const Q2& rhs)
{
using ref = detail::common_quantity_reference<Q1, Q2>;
using ret = quantity<typename ref::dimension, typename ref::unit, decltype(lhs.number() - rhs.number())>;
return ret(ret(lhs).number() - ret(rhs).number());
}
template<Quantity Q1, Quantity Q2>
requires(quantity_value_for_<std::multiplies<>, typename Q1::rep, typename Q2::rep>)
[[nodiscard]] constexpr Quantity auto operator*(const Q1& lhs, const Q2& rhs)
{
return detail::make_quantity<Q1::reference * Q2::reference>(lhs.number() * rhs.number());
}
template<Quantity Q1, Quantity Q2>
requires(quantity_value_for_<std::divides<>, typename Q1::rep, typename Q2::rep>)
[[nodiscard]] constexpr Quantity auto operator/(const Q1& lhs, const Q2& rhs)
{
gsl_ExpectsAudit(rhs.number() != quantity_values<typename Q2::rep>::zero());
return detail::make_quantity<Q1::reference / Q2::reference>(lhs.number() / rhs.number());
}
template<Quantity Q1, Quantity Q2>
requires(!floating_point_<typename Q1::rep>) && (!floating_point_<typename Q2::rep>) &&
(QuantityEquivalentTo<Q2, Q1> || Dimensionless<Q2>) &&
(quantity_value_for_<std::modulus<>, typename Q1::rep, typename Q2::rep>)
[[nodiscard]] constexpr Quantity auto operator%(const Q1& lhs, const Q2& rhs)
{
gsl_ExpectsAudit(rhs.number() != quantity_values<typename Q2::rep>::zero());
using ret = quantity<typename Q1::dimension, typename Q1::unit,
std::invoke_result_t<std::modulus<>, typename Q1::rep, typename Q2::rep>>;
return ret(lhs.number() % rhs.number());
}
template<Quantity Q1, QuantityEquivalentTo<Q1> Q2>
requires std::three_way_comparable_with<typename Q1::rep, typename Q2::rep>
[[nodiscard]] constexpr auto operator<=>(const Q1& lhs, const Q2& rhs)
{
using cq = std::common_type_t<Q1, Q2>;
return cq(lhs).number() <=> cq(rhs).number();
}
template<Quantity Q1, QuantityEquivalentTo<Q1> Q2>
requires std::equality_comparable_with<typename Q1::rep, typename Q2::rep>
[[nodiscard]] constexpr bool operator==(const Q1& lhs, const Q2& rhs)
{
using cq = std::common_type_t<Q1, Q2>;
return cq(lhs).number() == cq(rhs).number();
}
// type traits
namespace detail {
template<typename D, typename U, typename Rep>
inline constexpr bool is_quantity<quantity<D, U, Rep>> = true;
template<typename T>
requires units::is_derived_from_specialization_of<T, units::quantity>
inline constexpr bool is_quantity<T> = true;
} // namespace detail
} // namespace units