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Units and dimensions redesigned

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Mateusz Pusz committed 2019-12-01 19:47:58 +01:00
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commit 1b4e8a2127
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src/include/units/unit.h
+156 -324
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@@ -22,353 +22,185 @@
#pragma once
#include <units/dimension.h>
#include <units/bits/downcasting.h>
#include <units/bits/fixed_string.h>
#include <units/bits/type_traits.h>
#include <units/bits/unit_concept.h>
#include <units/derived_dimension.h>
#include <units/prefix.h>
#include <units/ratio.h>
#include <ratio>
namespace units {
template<Dimension D, Ratio R>
requires (R::num * R::den > 0)
struct unit : downcast_base<unit<D, R>> {
using dimension = D;
using ratio = R;
};
namespace detail {
// is_unit
template<typename U, Ratio R>
struct reference_unit : downcast_base<reference_unit<U, R>> {
using reference = U;
using ratio = R;
};
namespace detail {
} // namespace detail
template<typename T>
inline constexpr bool is_unit = false;
namespace detail {
template<typename D, typename R>
inline constexpr bool is_unit<unit<D, R>> = true;
// same_reference_units
template<DerivedDimension D, Unit... Us>
inline constexpr bool same_reference_units = false;
}
template<typename... Es, Unit... Us>
inline constexpr bool same_reference_units<derived_dimension<Es...>, Us...> =
(std::same_as<typename Es::dimension::coherent_unit::reference, typename Us::reference> && ...);
template<typename T>
concept Unit =
std::is_empty_v<T> &&
detail::is_unit<downcast_base_t<T>>;
// deduced_unit
template<typename Result, int UnitExpNum, int UnitExpDen, typename UnitRatio>
struct ratio_op;
// deduced_derived_unit
template<typename Result, int UnitExpDen, typename UnitRatio>
struct ratio_op<Result, 0, UnitExpDen, UnitRatio> {
using ratio = Result;
};
namespace detail {
template<typename Result, int UnitExpNum, int UnitExpDen, typename UnitRatio>
struct ratio_op {
using calc_ratio =
conditional<(UnitExpNum * UnitExpDen > 0), ratio_multiply<Result, UnitRatio>, ratio_divide<Result, UnitRatio>>;
static constexpr int value = (UnitExpNum * UnitExpDen > 0) ? (UnitExpNum - UnitExpDen) : (UnitExpNum + UnitExpDen);
using ratio = ratio_op<calc_ratio, value, UnitExpDen, UnitRatio>::ratio;
};
template<typename D>
struct get_unit_base_dim;
template<DerivedDimension D, Unit... Us>
struct derived_ratio;
template<typename E, typename... Rest>
struct get_unit_base_dim<dimension<E, Rest...>> {
static_assert(sizeof...(Rest) == 0, "Base unit expected");
using dimension = E::dimension;
};
template<Unit... Us>
struct derived_ratio<derived_dimension<>, Us...> {
using ratio = ::units::ratio<1>;
};
template<typename Result, int UnitExpNum, int UnitExpDen, typename UnitRatio>
struct ratio_op;
template<typename E, typename... ERest, Unit U, Unit... URest>
struct derived_ratio<derived_dimension<E, ERest...>, U, URest...> {
using rest_ratio = derived_ratio<derived_dimension<ERest...>, URest...>::ratio;
using ratio = ratio_op<rest_ratio, E::num, E::den, typename U::ratio>::ratio;
};
template<typename Result, int UnitExpDen, typename UnitRatio>
struct ratio_op<Result, 0, UnitExpDen, UnitRatio> {
using ratio = Result;
};
template<DerivedDimension D, Unit... Us>
using deduced_unit =
reference_unit<typename D::coherent_unit::reference, typename detail::derived_ratio<typename D::recipe, Us...>::ratio>;
template<typename Result, int UnitExpNum, int UnitExpDen, typename UnitRatio>
struct ratio_op {
using calc_ratio = conditional<(UnitExpNum * UnitExpDen > 0), ratio_multiply<Result, UnitRatio>,
ratio_divide<Result, UnitRatio>>;
static constexpr int value = (UnitExpNum * UnitExpDen > 0) ? (UnitExpNum - UnitExpDen) : (UnitExpNum + UnitExpDen);
using ratio = ratio_op<calc_ratio, value, UnitExpDen, UnitRatio>::ratio;
};
} // namespace detail
template<typename D, typename... Us>
struct derived_ratio;
/**
* @brief A starting point for a new hierarchy of units
*
* A unit is an entity defined and adopted by convention, with which any other quantity of
* the same kind can be compared to express the ratio of the second quantity to the first
* one as a number.
*
* Coherent unit is a unit that, for a given system of quantities and for a chosen set of
* base units, is a product of powers of base units with no other proportionality factor
* than one.
*
* This class allows definition of a new unnamed (in most cases coherent) derived unit of
* a specific derived dimension and it should be passed in this dimension's definition.
*
* @tparam Child inherited class type used by the downcasting facility (CRTP Idiom)
*/
template<typename Child>
struct unit : downcast_child<Child, detail::reference_unit<Child, ratio<1>>> {
static constexpr bool is_named = false;
using prefix_type = no_prefix;
};
template<typename... Us>
struct derived_ratio<dimension<>, Us...> {
using ratio = ::units::ratio<1>;
};
/**
* @brief A named unit
*
* Defines a named (in most cases coherent) unit that is then passed to a dimension definition.
* A named unit may be used by other units defined with the prefix of the same type, unless
* no_prefix is provided for PT template parameter (in such a case it is impossible to define
* a prefix unit based on this one).
*
* @tparam Child inherited class type used by the downcasting facility (CRTP Idiom)
* @tparam Symbol a short text representation of the unit
* @tparam PT no_prefix or a type of prefix family
*/
template<typename Child, basic_fixed_string Symbol, PrefixType PT>
struct named_unit : downcast_child<Child, detail::reference_unit<Child, ratio<1>>> {
static constexpr bool is_named = true;
static constexpr auto symbol = Symbol;
using prefix_type = PT;
};
template<typename E, typename... ERest, typename U, typename... URest>
struct derived_ratio<dimension<E, ERest...>, U, URest...> {
static_assert(same_dim<typename E::dimension, typename U::dimension>, "The order and number of units in `deduced_derived_unit<Us...>` should match dimensions provided in a `derived_dimension<>`");
static_assert(sizeof...(ERest) == sizeof...(URest), "The number of `deduced_derived_unit<Us...>` units should match the number of exponents provided to `derived_dimension<>`");
using rest_ratio = derived_ratio<dimension<ERest...>, URest...>::ratio;
using ratio = ratio_op<rest_ratio, E::num, E::den, typename U::ratio>::ratio;
};
/**
* @brief A scaled unit
*
* Defines a new named unit that is a scaled version of another unit. Such unit can be used by
* other units defined with the prefix of the same type, unless no_prefix is provided for PT
* template parameter (in such a case it is impossible to define a prefix unit based on this
* one).
*
* @tparam Child inherited class type used by the downcasting facility (CRTP Idiom)
* @tparam Symbol a short text representation of the unit
* @tparam PT no_prefix or a type of prefix family
* @tparam R a scale to apply to U
* @tparam U a reference unit to scale
*/
template<typename Child, basic_fixed_string Symbol, PrefixType PT, Ratio R, Unit U>
struct scaled_unit : downcast_child<Child, detail::reference_unit<typename U::reference, ratio_multiply<R, typename U::ratio>>> {
static constexpr bool is_named = true;
static constexpr auto symbol = Symbol;
using prefix_type = PT;
};
template<typename... Es>
constexpr auto exp_count(dimension<Es...>)
{
return sizeof...(Es);
}
/**
* @brief A prefixed unit
*
* Defines a new unit that is a scaled version of another unit by the provided prefix. It is
* only possible to create such a unit if the given prefix type matches the one defined in a
* reference unit.
*
* @tparam Child inherited class type used by the downcasting facility (CRTP Idiom)
* @tparam P prefix to be appied to the reference unit
* @tparam U reference unit
*/
template<typename Child, Prefix P, Unit U>
requires std::same_as<typename P::prefix_type, typename U::prefix_type>
// TODO replace with the below code when gcc will stop to crash on it ;-)
// struct prefixed_unit : scaled_unit<Child, P::symbol + U::symbol, typename P::prefix_type,
// ratio_multiply<typename P::ratio, typename U::ratio>,
// typename U::reference> {};
struct prefixed_unit :
downcast_child<Child, detail::reference_unit<typename U::reference, ratio_multiply<typename P::ratio, typename U::ratio>>> {
static constexpr bool is_named = true;
static constexpr auto symbol = P::symbol + U::symbol;
using prefix_type = P::prefix_type;
};
template<typename U>
inline constexpr bool is_unit_of_base_dimension = (exp_count(typename U::dimension::base_type()) == 1);
/**
* @brief A unit with a deduced ratio and symbol
*
* Defines a new unit with a deduced ratio and symbol based on the recipe from the provided
* derived dimension. The number and order of provided units should match the recipe of
* dimension.
*
* @tparam Child inherited class type used by the downcasting facility (CRTP Idiom)
* @tparam Dim a derived dimension recipe to use for deduction
* @tparam U the unit of the first composite dimension from provided derived dimension's recipe
* @tparam URest the units for the rest of dimensions from the recipe
*/
template<typename Child, DerivedDimension Dim, Unit U, Unit... URest>
requires detail::same_reference_units<typename Dim::recipe, U, URest...> &&
(U::is_named && (URest::is_named && ... && true))
struct deduced_unit : downcast_child<Child, detail::deduced_unit<Dim, U, URest...>> {
static constexpr bool is_named = false;
static constexpr auto symbol = basic_fixed_string{""}; // detail::deduced_symbol_text<Dim, U, Us...>();
using prefix_type = no_prefix;
};
template<Unit... Us>
inline constexpr bool are_units_of_base_dimension = (is_unit_of_base_dimension<Us> && ...);
template<Dimension D, Unit... Us>
using deduced_derived_unit =
unit<D, typename detail::derived_ratio<std::conditional_t<are_units_of_base_dimension<Us...>,
typename D::base_type, typename D::recipe>, Us...>::ratio>;
template<int Value>
requires (0 <= Value) && (Value < 10)
inline constexpr basic_fixed_string superscript_number = "\u2070";
// template<> inline constexpr basic_fixed_string superscript_number<0> = "\u2070";
template<> inline constexpr basic_fixed_string superscript_number<1> = "\u00b9";
template<> inline constexpr basic_fixed_string superscript_number<2> = "\u00b2";
template<> inline constexpr basic_fixed_string superscript_number<3> = "\u00b3";
template<> inline constexpr basic_fixed_string superscript_number<4> = "\u2074";
template<> inline constexpr basic_fixed_string superscript_number<5> = "\u2075";
template<> inline constexpr basic_fixed_string superscript_number<6> = "\u2076";
template<> inline constexpr basic_fixed_string superscript_number<7> = "\u2077";
template<> inline constexpr basic_fixed_string superscript_number<8> = "\u2078";
template<> inline constexpr basic_fixed_string superscript_number<9> = "\u2079";
template<int Value>
requires (Value >= 0)
constexpr auto superscript()
{
if constexpr(Value < 10)
return superscript_number<Value>;
else
return superscript<Value / 10>() + superscript<Value % 10>();
}
template<int Value>
requires (Value >= 0)
constexpr auto regular()
{
if constexpr(Value < 10)
return basic_fixed_string(static_cast<char>('0' + Value));
else
return regular<Value / 10>() + regular<Value % 10>();
}
template<typename Ratio>
constexpr auto ratio_text()
{
if constexpr(Ratio::num != 1 || Ratio::den != 1) {
auto txt = basic_fixed_string("[") + regular<Ratio::num>();
if constexpr(Ratio::den == 1) {
return txt + basic_fixed_string("]");
}
else {
return txt + basic_fixed_string("/") + regular<Ratio::den>() + basic_fixed_string("]");
}
}
else {
return basic_fixed_string("");
}
}
template<typename Ratio, typename PrefixType>
constexpr auto prefix_or_ratio_text()
{
if constexpr(Ratio::num != 1 || Ratio::den != 1) {
if constexpr (!std::same_as<PrefixType, no_prefix>) {
using prefix = downcast<detail::prefix_base<PrefixType, Ratio>>;
if constexpr(!std::same_as<prefix, prefix_base<PrefixType, Ratio>>) {
// print as a prefixed unit
return prefix::symbol;
}
else {
// print as a ratio of the coherent unit
return ratio_text<Ratio>();
}
}
else {
// print as a ratio of the coherent unit
return ratio_text<Ratio>();
}
}
}
template<bool Divide, std::size_t Idx>
constexpr auto operator_text()
{
if constexpr(Idx == 0) {
if constexpr(Divide) {
return basic_fixed_string("1/");
}
else {
return basic_fixed_string("");
}
}
else {
if constexpr(Divide) {
return basic_fixed_string("/");
}
else {
return basic_fixed_string("⋅");
}
}
}
template<typename E, basic_fixed_string Symbol, std::size_t Idx>
constexpr auto exp_text()
{
// get calculation operator + symbol
const auto txt = operator_text<E::num < 0, Idx>() + Symbol;
if constexpr(E::den != 1) {
// add root part
return txt + basic_fixed_string("^(") + regular<abs(E::num)>() + basic_fixed_string("/") + regular<E::den>() + basic_fixed_string(")");
}
else if constexpr(abs(E::num) != 1) {
// add exponent part
return txt + superscript<abs(E::num)>();
}
else {
return txt;
}
}
template<typename Dim>
constexpr auto dimension_symbol()
{
if constexpr(BaseDimension<Dim>)
return Dim::symbol;
else
// coherent derived unit
return downcast<unit<Dim, ratio<1>>>::symbol;
}
template<typename... Es, std::size_t... Idxs>
constexpr auto base_symbol_text_impl(dimension<Es...>, std::index_sequence<Idxs...>)
{
return (exp_text<Es, dimension_symbol<typename Es::dimension>(), Idxs>() + ...);
}
template<typename... Es>
constexpr auto base_symbol_text(dimension<Es...> d)
{
return base_symbol_text_impl(d, std::index_sequence_for<Es...>());
}
template<typename... Es>
constexpr bool all_named(dimension<Es...>)
{
return (downcast<unit<typename Es::dimension, ratio<1>>>::is_named && ...);
}
template<typename Dim>
constexpr auto base_symbol_text()
{
using recipe = typename Dim::recipe;
if constexpr(all_named(recipe()))
return base_symbol_text(recipe());
else
return base_symbol_text(Dim());
}
template<typename E, typename U, std::size_t Idx>
constexpr auto exp_validate_and_text()
{
static_assert(same_dim<typename E::dimension, typename U::dimension>, "The order and number of units in `deduced_derived_unit<Us...>` should match dimensions provided in a `derived_dimension<>`");
return exp_text<E, U::symbol, Idx>();
}
template<typename... Us, typename... Es, std::size_t... Idxs>
constexpr auto deduced_symbol_text_impl(dimension<Es...>, std::index_sequence<Idxs...>)
{
return (exp_validate_and_text<Es, Us, Idxs>() + ...);
}
template<typename... Us, typename... Es>
constexpr auto deduced_symbol_text(dimension<Es...> d)
{
static_assert(sizeof...(Es) == sizeof...(Us), "The number of `deduced_derived_unit<Us...>` units should match the number of exponents provided to `derived_dimension<>`");
return deduced_symbol_text_impl<Us...>(d, std::index_sequence_for<Es...>());
}
template<typename Dim, typename... Us>
constexpr auto deduced_symbol_text()
{
if constexpr(are_units_of_base_dimension<Us...>)
return deduced_symbol_text<Us...>(typename Dim::base_type());
else
return deduced_symbol_text<Us...>(typename Dim::recipe());
}
template<typename Unit>
constexpr auto unit_text()
{
if constexpr(!is_unit<Unit>) {
// Unit is a downcasted derived unit child class already so just print defined symbol immediately
return Unit::symbol;
}
else {
// we are dealing with a non-user-defined unit here
using ratio = Unit::ratio;
using dim = Unit::dimension;
if constexpr(!is_dimension<dim>) {
// downcasted user-defined dimension
// print as a prefix or ratio of a coherent unit symbol defined by the user
using coherent_unit = downcast<units::unit<dim, units::ratio<1>>>;
return prefix_or_ratio_text<ratio, typename coherent_unit::prefix_type>() + coherent_unit::symbol;
}
else {
// print as a ratio of a coherent unit + coherent unit dimensions and their exponents
return ratio_text<ratio>() + base_symbol_text(dim{});
}
}
}
} // namespace detail
// derived_unit
template<typename Child, Dimension Dim, basic_fixed_string Symbol, PrefixType PT>
struct named_coherent_derived_unit : downcast_child<Child, unit<Dim, ratio<1>>> {
static constexpr bool is_named = true;
static constexpr auto symbol = Symbol;
using prefix_type = PT;
};
template<typename Child, Dimension Dim>
struct coherent_derived_unit : downcast_child<Child, unit<Dim, ratio<1>>> {
static constexpr bool is_named = false;
static constexpr auto symbol = detail::base_symbol_text<Dim>();
using prefix_type = no_prefix;
};
template<typename Child, Dimension Dim, basic_fixed_string Symbol, Ratio R, PrefixType PT = no_prefix>
struct named_scaled_derived_unit : downcast_child<Child, unit<Dim, R>> {
static constexpr bool is_named = true;
static constexpr auto symbol = Symbol;
using prefix_type = PT;
};
template<typename Child, Dimension Dim, basic_fixed_string Symbol, PrefixType PT, Unit U, Unit... Us>
struct named_deduced_derived_unit : downcast_child<Child, detail::deduced_derived_unit<Dim, U, Us...>> {
static constexpr bool is_named = true;
static constexpr auto symbol = Symbol;
using prefix_type = PT;
};
template<typename Child, Dimension Dim, Unit U, Unit... Us>
requires U::is_named && (Us::is_named && ... && true)
struct deduced_derived_unit : downcast_child<Child, detail::deduced_derived_unit<Dim, U, Us...>> {
static constexpr bool is_named = false;
static constexpr auto symbol = detail::deduced_symbol_text<Dim, U, Us...>();
using prefix_type = no_prefix;
};
template<typename Child, Prefix P, Unit U>
requires (!std::same_as<typename U::prefix_type, no_prefix>)
struct prefixed_derived_unit : downcast_child<Child, unit<typename U::dimension, ratio_multiply<typename P::ratio, typename U::ratio>>> {
static constexpr bool is_named = true;
static constexpr auto symbol = P::symbol + U::symbol;
using prefix_type = P::prefix_type;
};
// template<typename Child, Dimension Dim, basic_fixed_string Symbol, PrefixType PT, Unit U, Unit... Us>
// struct named_deduced_derived_unit : downcast_child<Child, detail::deduced_derived_unit<Dim, U, Us...>> {
// static constexpr bool is_named = true;
// static constexpr auto symbol = Symbol;
// using prefix_type = PT;
// };
} // namespace units