xo-alloc/include/xo/unit/quantity.hpp

62 lines
2.6 KiB
C++

/** @file quantity.hpp
*
* Author: Roland Conybeare
**/
#pragma once
#include "natural_unit.hpp"
#include "scaled_unit.hpp"
namespace xo {
namespace qty {
/** @class quantity
* @brief represent a scalar quantity with associated units.
*
* Enforce dimensional consistency at compile time.
* sizeof(quantity) == sizeof(Repr).
**/
template <
typename Repr = double,
typename Int = std::int64_t,
natural_unit<Int> NaturalUnit = natural_unit<Int>(),
typename Int2x = detail::width2x<Int>
>
class quantity {
public:
using repr_type = Repr;
using unit_type = natural_unit<Int>;
using ratio_int_type = Int;
using ratio_int2x_type = Int2x;
public:
constexpr quantity() : scale_{0} {}
explicit constexpr quantity(Repr scale) : scale_{scale} {}
constexpr const repr_type & scale() const { return scale_; }
constexpr const unit_type & unit() const { return s_unit; }
constexpr nu_abbrev_type abbrev() const { return s_unit.abbrev(); }
public: /* need public members so that a quantity instance can be a non-type template parameter (is a structural type) */
static constexpr natural_unit<Int> s_unit = NaturalUnit;
Repr scale_ = Repr{};
};
namespace qty {
inline constexpr auto picograms(double x) { return quantity<double, std::int64_t, nu::picogram>(x); }
inline constexpr auto nanograms(double x) { return quantity<double, std::int64_t, nu::nanogram>(x); }
inline constexpr auto micrograms(double x) { return quantity<double, std::int64_t, nu::microgram>(x); }
inline constexpr auto milligrams(double x) { return quantity<double, std::int64_t, nu::milligram>(x); }
inline constexpr auto grams(double x) { return quantity<double, std::int64_t, nu::gram>(x); }
inline constexpr auto kilograms(double x) { return quantity<double, std::int64_t, nu::kilogram>(x); }
inline constexpr auto tonnes(double x) { return quantity<double, std::int64_t, nu::tonne>(x); }
inline constexpr auto kilotonnes(double x) { return quantity<double, std::int64_t, nu::kilotonne>(x); }
inline constexpr auto megatonnes(double x) { return quantity<double, std::int64_t, nu::megatonne>(x); }
inline constexpr auto gigatonnes(double x) { return quantity<double, std::int64_t, nu::gigatonne>(x); }
}
} /*namespace qty*/
} /*namespace xo*/
/** end quantity.hpp **/