167 lines
9.4 KiB
C++
167 lines
9.4 KiB
C++
/** @file basis_unit.hpp **/
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#pragma once
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#include "dimension.hpp"
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#include "basis_unit_abbrev.hpp"
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#include "xo/ratio/ratio.hpp"
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namespace xo {
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namespace qty {
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/** @class basis_unit2
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* @brief A dimensionless multiple of a single natively-specified basis dimension
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*
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* For example "3600 minutes" or "1e-6 grams"
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**/
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struct basis_unit {
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public:
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constexpr basis_unit() = default;
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constexpr basis_unit(dim native_dim, const scalefactor_ratio_type & scalefactor)
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: native_dim_{native_dim},
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scalefactor_{scalefactor}
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{}
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constexpr dim native_dim() const { return native_dim_; }
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constexpr const scalefactor_ratio_type & scalefactor() const { return scalefactor_; }
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constexpr basis_unit2_abbrev_type abbrev() const {
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return abbrev::basis_unit2_abbrev(native_dim_,
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scalefactor_);
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}
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constexpr basis_unit & operator=(const basis_unit & x) = default;
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public: /* need public members so that a basis_unit instance can be a non-type template parameter (a structural type) */
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/** @brief identifies a native unit, e.g. time (in seconds) **/
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dim native_dim_ = dim::invalid;
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/** @brief this unit defined as multiple scalefactor times native unit **/
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scalefactor_ratio_type scalefactor_;
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};
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inline constexpr bool
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operator==(const basis_unit & x, const basis_unit & y)
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{
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return ((x.native_dim_ == y.native_dim_)
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&& (x.scalefactor_ == y.scalefactor_));
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}
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inline constexpr bool
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operator!=(const basis_unit & x, const basis_unit & y)
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{
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return ((x.native_dim_ != y.native_dim_)
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|| (x.scalefactor_ != y.scalefactor_));
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}
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namespace bu {
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// ----- mass -----
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constexpr basis_unit picogram = basis_unit(dim::mass, scalefactor_ratio_type( 1, 1000000000000));
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constexpr basis_unit nanogram = basis_unit(dim::mass, scalefactor_ratio_type( 1, 1000000000));
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constexpr basis_unit microgram = basis_unit(dim::mass, scalefactor_ratio_type( 1, 1000000));
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constexpr basis_unit milligram = basis_unit(dim::mass, scalefactor_ratio_type( 1, 1000));
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constexpr basis_unit gram = basis_unit(dim::mass, scalefactor_ratio_type( 1, 1));
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constexpr basis_unit kilogram = basis_unit(dim::mass, scalefactor_ratio_type( 1000, 1));
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constexpr basis_unit tonne = basis_unit(dim::mass, scalefactor_ratio_type( 1000000, 1));
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constexpr basis_unit kilotonne = basis_unit(dim::mass, scalefactor_ratio_type( 1000000000, 1));
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constexpr basis_unit megatonne = basis_unit(dim::mass, scalefactor_ratio_type(1000000000000, 1));
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constexpr basis_unit gigatonne = basis_unit(dim::mass, scalefactor_ratio_type(1000000000000000, 1));
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// ----- distance -----
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/* International spelling */
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constexpr basis_unit picometre = basis_unit(dim::distance, scalefactor_ratio_type( 1, 1000000000000));
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constexpr basis_unit nanometre = basis_unit(dim::distance, scalefactor_ratio_type( 1, 1000000000));
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constexpr basis_unit micrometre = basis_unit(dim::distance, scalefactor_ratio_type( 1, 1000000));
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constexpr basis_unit millimetre = basis_unit(dim::distance, scalefactor_ratio_type( 1, 1000));
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constexpr basis_unit metre = basis_unit(dim::distance, scalefactor_ratio_type( 1, 1));
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constexpr basis_unit kilometre = basis_unit(dim::distance, scalefactor_ratio_type( 1000, 1));
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constexpr basis_unit megametre = basis_unit(dim::distance, scalefactor_ratio_type( 1000000, 1));
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constexpr basis_unit gigametre = basis_unit(dim::distance, scalefactor_ratio_type( 1000000000, 1));
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constexpr basis_unit lightsecond = basis_unit(dim::distance, scalefactor_ratio_type( 299792458, 1));
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constexpr basis_unit astronomicalunit = basis_unit(dim::distance, scalefactor_ratio_type( 149597870700, 1));
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/* US spelling */
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constexpr basis_unit picometer = picometre;
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constexpr basis_unit nanometer = nanometre;
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constexpr basis_unit micrometer = micrometre;
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constexpr basis_unit millimeter = millimetre;
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constexpr basis_unit meter = metre;
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constexpr basis_unit kilometer = kilometre;
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constexpr basis_unit megameter = megametre;
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constexpr basis_unit gigameter = gigametre;
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// ----- time -----
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constexpr basis_unit picosecond = basis_unit(dim::time, scalefactor_ratio_type( 1, 1000000000000));
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constexpr basis_unit nanosecond = basis_unit(dim::time, scalefactor_ratio_type( 1, 1000000000));
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constexpr basis_unit microsecond = basis_unit(dim::time, scalefactor_ratio_type( 1, 1000000));
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constexpr basis_unit millisecond = basis_unit(dim::time, scalefactor_ratio_type( 1, 1000));
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constexpr basis_unit second = basis_unit(dim::time, scalefactor_ratio_type( 1, 1));
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constexpr basis_unit minute = basis_unit(dim::time, scalefactor_ratio_type( 60, 1));
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constexpr basis_unit hour = basis_unit(dim::time, scalefactor_ratio_type( 3600, 1));
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constexpr basis_unit day = basis_unit(dim::time, scalefactor_ratio_type( 24*3600, 1));
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constexpr basis_unit week = basis_unit(dim::time, scalefactor_ratio_type( 7*24*3600, 1));
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constexpr basis_unit month = basis_unit(dim::time, scalefactor_ratio_type( 30*24*3600, 1));
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constexpr basis_unit year = basis_unit(dim::time, scalefactor_ratio_type((365*24+6)*3600, 1));
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/* alt conventions used in finance */
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constexpr basis_unit year365 = basis_unit(dim::time, scalefactor_ratio_type( 365*24*3600, 1));
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constexpr basis_unit year360 = basis_unit(dim::time, scalefactor_ratio_type( 360*24*3600, 1));
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/* 250 = approx number of trading days in a calendar year */
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constexpr basis_unit year250 = basis_unit(dim::time, scalefactor_ratio_type( 250*24*3600, 1));
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// ----- currency -----
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/* pseudounit -- placeholder for any actual currency amount */
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constexpr basis_unit currency = basis_unit(dim::currency, scalefactor_ratio_type( 1, 1));
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// ----- price -----
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/* psuedounit -- context-dependent interpretation */
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constexpr basis_unit price = basis_unit(dim::price, scalefactor_ratio_type( 1, 1));
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}
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namespace units {
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/** for runtime work, would like to be able to promptly find special abbreviation
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* keyed by (native_dim, scalefactor).
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*
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* Also want to support compile-time-only unit computation.
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* Since constexpr unordered containers aren't obviously feasible (as of c++23).
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*
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* Solution adopted here is to support introduction of scaled native units
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* only at compile time, at least for now
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**/
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// ----- scaled_native_unit_abbrev_helper -----
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/* Require: InnerScale is ratio type; InnerScale >= 1
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*
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* NOTE: clang 18 doesn't accept that scalefactor_ratio_type is a 'structural type'
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*/
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template <dim BasisDim, std::int64_t InnerScaleNum = 1, std::int64_t InnerScaleDen = 1>
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struct scaled_native_unit2_abbrev;
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template <dim BasisDim>
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struct scaled_native_unit2_abbrev<BasisDim, 1, 1> {
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static constexpr const basis_unit2_abbrev_type value
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= (basis_unit2_abbrev_type::from_flatstring
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(native_unit2_v[static_cast<uint32_t>(BasisDim)]
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.abbrev_str()));
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};
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inline
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constexpr basis_unit2_abbrev_type
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bu_fallback_abbrev(dim basis_dim,
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const scalefactor_ratio_type & scalefactor)
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{
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return (basis_unit2_abbrev_type::from_flatstring
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(flatstring_concat
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(scalefactor.to_str<basis_unit2_abbrev_type::fixed_capacity>(),
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native_unit2_v[static_cast<std::uint32_t>(basis_dim)].abbrev_str())));
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}
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}
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} /*namespace qty*/
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} /*namespace xo*/
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/** end basis_unit.hpp **/
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