/** @file basis_unit.hpp **/ #pragma once #include "dimension.hpp" #include "basis_unit_abbrev.hpp" #include "xo/ratio/ratio.hpp" namespace xo { namespace qty { /** @class basis_unit * @brief A dimensionless multiple of a single natively-specified basis dimension * * For example "3600 minutes" or "1e-6 grams" **/ struct basis_unit { public: /** @defgroup basis-unit-constructors basis_unit constructors **/ ///@{ constexpr basis_unit() = default; constexpr basis_unit(dimension native_dim, const scalefactor_ratio_type & scalefactor) : native_dim_{native_dim}, scalefactor_{scalefactor} {} ///@} /** @defgroup basis-unit-access-methods basis_unit access methods **/ ///@{ constexpr dimension native_dim() const { return native_dim_; } constexpr const scalefactor_ratio_type & scalefactor() const { return scalefactor_; } ///@} constexpr basis_unit2_abbrev_type abbrev() const { return abbrev::basis_unit2_abbrev(native_dim_, scalefactor_); } public: /* need public members so that a basis_unit instance can be a non-type template parameter (a structural type) */ /** @defgroup basis-unit-instance-vars **/ ///@{ /** @brief identifies a native unit, e.g. time (in seconds) **/ dimension native_dim_ = dimension::invalid; /** @brief this unit defined as multiple scalefactor times native unit **/ scalefactor_ratio_type scalefactor_; ///@} }; /** @defgroup basis-unit-comparison-support basis_unit comparisons **/ ///@{ inline constexpr bool operator==(const basis_unit & x, const basis_unit & y) { return ((x.native_dim_ == y.native_dim_) && (x.scalefactor_ == y.scalefactor_)); } inline constexpr bool operator!=(const basis_unit & x, const basis_unit & y) { return ((x.native_dim_ != y.native_dim_) || (x.scalefactor_ != y.scalefactor_)); } ///@} namespace detail { namespace bu { // ----- mass ----- constexpr basis_unit mass_unit(std::int64_t num, std::int64_t den) { return basis_unit(dimension::mass, scalefactor_ratio_type(num, den)); } /** @defgroup basis-unit-mass-units **/ ///@{ constexpr basis_unit picogram = mass_unit( 1, 1000000000000); constexpr basis_unit nanogram = mass_unit( 1, 1000000000); constexpr basis_unit microgram = mass_unit( 1, 1000000); constexpr basis_unit milligram = mass_unit( 1, 1000); constexpr basis_unit gram = mass_unit( 1, 1); constexpr basis_unit kilogram = mass_unit( 1000, 1); constexpr basis_unit tonne = mass_unit( 1000000, 1); constexpr basis_unit kilotonne = mass_unit( 1000000000, 1); constexpr basis_unit megatonne = mass_unit( 1000000000000, 1); constexpr basis_unit gigatonne = mass_unit(1000000000000000, 1); ///@} // ----- distance ----- constexpr basis_unit distance_unit(std::int64_t num, std::int64_t den) { return basis_unit(dimension::distance, scalefactor_ratio_type(num, den)); } /** @defgroup basis-unit-distance-units **/ ///@{ /* International spelling */ constexpr basis_unit picometre = distance_unit( 1, 1000000000000); constexpr basis_unit nanometre = distance_unit( 1, 1000000000); constexpr basis_unit micrometre = distance_unit( 1, 1000000); constexpr basis_unit millimetre = distance_unit( 1, 1000); constexpr basis_unit metre = distance_unit( 1, 1); constexpr basis_unit kilometre = distance_unit( 1000, 1); constexpr basis_unit megametre = distance_unit( 1000000, 1); constexpr basis_unit gigametre = distance_unit( 1000000000, 1); constexpr basis_unit lightsecond = distance_unit( 299792458, 1); constexpr basis_unit astronomicalunit = distance_unit( 149597870700, 1); /* US spelling */ constexpr basis_unit picometer = picometre; constexpr basis_unit nanometer = nanometre; constexpr basis_unit micrometer = micrometre; constexpr basis_unit millimeter = millimetre; constexpr basis_unit meter = metre; constexpr basis_unit kilometer = kilometre; constexpr basis_unit megameter = megametre; constexpr basis_unit gigameter = gigametre; /** @brief basis-unit representing 1 inch; defined as exactly 1/12 feet **/ constexpr basis_unit inch = distance_unit( 3048, 120000); /** @brief basis-unit representing 1 foot; defined as exactly 0.3048 meters **/ constexpr basis_unit foot = distance_unit( 3048, 10000); /** @brief basis-unit representing 1 yard; defined as exactly 3 feet **/ constexpr basis_unit yard = distance_unit( 3*3048, 10000); /** @brief basis-unit representing 1 mile; defined as exactly 1760 yards = 5280 feet **/ constexpr basis_unit mile = distance_unit( 5280*3048, 10000); ///@} // ----- time ----- constexpr basis_unit time_unit(std::int64_t num, std::int64_t den) { return basis_unit(dimension::time, scalefactor_ratio_type(num, den)); } /** @defgroup basis-unit-time-units **/ ///@{ constexpr basis_unit picosecond = time_unit( 1, 1000000000000); constexpr basis_unit nanosecond = time_unit( 1, 1000000000); constexpr basis_unit microsecond = time_unit( 1, 1000000); constexpr basis_unit millisecond = time_unit( 1, 1000); constexpr basis_unit second = time_unit( 1, 1); constexpr basis_unit minute = time_unit( 60, 1); constexpr basis_unit hour = time_unit( 3600, 1); constexpr basis_unit day = time_unit( 24*3600, 1); constexpr basis_unit week = time_unit( 7*24*3600, 1); constexpr basis_unit month = time_unit( 30*24*3600, 1); constexpr basis_unit year = time_unit( (365*24+6)*3600, 1); /* alt conventions used in finance */ constexpr basis_unit year365 = time_unit( 365*24*3600, 1); constexpr basis_unit year360 = time_unit( 360*24*3600, 1); /* 250 = approx number of trading days in a calendar year */ constexpr basis_unit year250 = time_unit( 250*24*3600, 1); constexpr basis_unit century = time_unit( 100L*(365*24+6)*3600, 1); constexpr basis_unit millenium = time_unit(1000L*(365*24+6)*3600, 1); ///@} // ----- currency ----- /** @defgroup basis-unit-misc-units **/ ///@{ /* pseudounit -- placeholder for any actual currency amount */ constexpr basis_unit currency = basis_unit(dim::currency, scalefactor_ratio_type( 1, 1)); // ----- price ----- /* psuedounit -- context-dependent interpretation */ constexpr basis_unit price = basis_unit(dim::price, scalefactor_ratio_type( 1, 1)); ///@} } /*namespace bu*/ } /*namespace detail*/ namespace units { /** for runtime work, would like to be able to promptly find special abbreviation * keyed by (native_dim, scalefactor). * * Also want to support compile-time-only unit computation. * Since constexpr unordered containers aren't obviously feasible (as of c++23). * * Solution adopted here is to support introduction of scaled native units * only at compile time, at least for now **/ // ----- scaled_native_unit_abbrev_helper ----- /* Require: InnerScale is ratio type; InnerScale >= 1 */ template struct scaled_native_unit2_abbrev; template struct scaled_native_unit2_abbrev { static constexpr const basis_unit2_abbrev_type value = (basis_unit2_abbrev_type::from_flatstring (native_unit2_v[static_cast(BasisDim)] .abbrev_str())); }; inline constexpr basis_unit2_abbrev_type bu_fallback_abbrev(dim basis_dim, const scalefactor_ratio_type & scalefactor) { return (basis_unit2_abbrev_type::from_flatstring (flatstring_concat (scalefactor.to_str(), native_unit2_v[static_cast(basis_dim)].abbrev_str()))); } } } /*namespace qty*/ } /*namespace xo*/ /** end basis_unit.hpp **/