80 lines
2.3 KiB
C++
80 lines
2.3 KiB
C++
/* @file dim_util.hpp */
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#pragma once
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#include <cstdint>
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namespace xo {
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namespace qty {
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enum class dim {
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invalid = -1,
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/** weight. native unit = 1 gram **/
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mass,
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/** distance. native unit = 1 meter **/
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distance,
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/** time. native unit = 1 second **/
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time,
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/** a currency amount. native unit depends on actual currency.
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* For USD: one US dollar.
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*
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* NOTE: unit system isn't suitable for multicurrency work:
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* (1usd + 1eur) is well-defined, but (1sec + 1m) is not.
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**/
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currency,
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/** a screen price **/
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price,
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/** comes last, counts entries **/
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n_dim
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};
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inline const char *
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dim2str(dim x)
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{
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switch(x) {
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case dim::mass: return "mass";
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case dim::distance: return "distance";
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case dim::time: return "time";
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case dim::currency: return "currency";
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case dim::price: return "price";
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default: break;
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}
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return "?dim";
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}
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static constexpr std::size_t n_dim = static_cast<std::size_t>(dim::n_dim);
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enum class native_unit_id {
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gram,
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meter,
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second,
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currency,
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price
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};
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template <dim Dim>
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struct native_unit_for;
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template <>
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struct native_unit_for<dim::mass> { static constexpr auto value = native_unit_id::gram; };
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template <>
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struct native_unit_for<dim::distance> { static constexpr auto value = native_unit_id::meter; };
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template <>
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struct native_unit_for<dim::time> { static constexpr auto value = native_unit_id::second; };
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template <>
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struct native_unit_for<dim::currency> { static constexpr auto value = native_unit_id::currency; };
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template <>
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struct native_unit_for<dim::price> { static constexpr auto value = native_unit_id::price; };
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template <dim Dim>
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constexpr auto native_unit_for_v = native_unit_for<Dim>::value;
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} /*namespace qty*/
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} /*namespace xo*/
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/* end dim_util.hpp */
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