forked from OctaForge/libostd
236 lines
7.6 KiB
C++
236 lines
7.6 KiB
C++
/* Type traits for OctaSTD.
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*
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* This file is part of OctaSTD. See COPYING.md for futher information.
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*/
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#ifndef OCTA_TRAITS_H
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#define OCTA_TRAITS_H
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#include <stddef.h>
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#include "octa/types.h"
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#include "octa/utility.h"
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namespace octa {
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/* conditional */
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template<bool cond, typename T, typename U>
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struct Conditional {
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typedef T type;
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};
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template<typename T, typename U>
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struct Conditional<false, T, U> {
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typedef U type;
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};
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/* removers */
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template<typename T> using RemoveReference = internal::RemoveReference<T>;
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template<typename T> struct RemoveConst { typedef T type; };
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template<typename T> struct RemoveConst<const T> { typedef T type; };
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template<typename T> struct RemoveVolatile { typedef T type; };
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template<typename T> struct RemoveVolatile<volatile T> { typedef T type; };
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template<typename T>
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struct RemoveConstVolatile {
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typedef typename RemoveVolatile<typename RemoveConst<T>::type>::type type;
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};
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/* integral constant */
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template<typename T, T val>
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struct IntegralConstant {
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static constexpr const T value = val;
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typedef T value_type;
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typedef IntegralConstant<T, val> type;
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constexpr operator value_type() const { return value; }
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constexpr value_type operator()() const { return value; }
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};
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typedef IntegralConstant<bool, true> true_t;
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typedef IntegralConstant<bool, false> false_t;
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template<typename T, T val> constexpr const T IntegralConstant<T, val>::value;
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/* is integer */
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template<typename T> struct IsIntegerBase: false_t {};
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template<> struct IsIntegerBase<bool >: true_t {};
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template<> struct IsIntegerBase<char >: true_t {};
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template<> struct IsIntegerBase<uchar >: true_t {};
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template<> struct IsIntegerBase<schar >: true_t {};
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template<> struct IsIntegerBase<short >: true_t {};
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template<> struct IsIntegerBase<ushort>: true_t {};
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template<> struct IsIntegerBase<int >: true_t {};
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template<> struct IsIntegerBase<uint >: true_t {};
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template<> struct IsIntegerBase<long >: true_t {};
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template<> struct IsIntegerBase<ulong >: true_t {};
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template<> struct IsIntegerBase<llong >: true_t {};
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template<> struct IsIntegerBase<ullong>: true_t {};
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template<typename T>
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struct IsInteger: IsIntegerBase<typename RemoveConstVolatile<T>::type> {};
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/* is floating point */
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template<typename T> struct IsFloatBase : false_t {};
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template<> struct IsFloatBase<float >: true_t {};
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template<> struct IsFloatBase<double >: true_t {};
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template<> struct IsFloatBase<ldouble>: true_t {};
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template<typename T>
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struct IsFloat: IsFloatBase<typename RemoveConstVolatile<T>::type> {};
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/* is number */
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template<typename T> struct IsNumber: IntegralConstant<bool,
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(IsInteger<T>::value || IsFloat<T>::value)
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> {};
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/* is pointer */
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template<typename > struct IsPointerBase : false_t {};
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template<typename T> struct IsPointerBase<T *>: true_t {};
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template<typename T>
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struct IsPointer: IsPointerBase<typename RemoveConstVolatile<T>::type> {};
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/* is pointer to member function */
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template<typename > struct IsMemberPointerBase: false_t {};
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template<typename T, typename U>
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struct IsMemberPointerBase<T U::*>: true_t {};
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template<typename T>
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struct IsMemberPointer: IsMemberPointerBase<
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typename RemoveConstVolatile<T>::type
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> {};
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/* is null pointer */
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template<typename> struct IsNullPointerBase : false_t {};
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template< > struct IsNullPointerBase<nullptr_t>: true_t {};
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template<typename T>
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struct IsNullPointer: IsNullPointerBase<
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typename RemoveConstVolatile<T>::type
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> {};
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/* is POD: currently wrong */
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template<typename T> struct IsPOD: IntegralConstant<bool,
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(IsInteger<T>::value || IsFloat<T>::value || IsPointer<T>::value)
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> {};
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/* is class */
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struct IsClassBase {
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template<typename T> static char test(void (T::*)(void));
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template<typename > static int test(...);
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};
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template<typename T>
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struct IsClass: IntegralConstant<bool,
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sizeof(IsClassBase::test<T>(0)) == 1
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> {};
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/* type equality */
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template<typename, typename> struct IsEqual : false_t {};
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template<typename T > struct IsEqual<T, T>: true_t {};
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/* is lvalue reference */
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template<typename > struct IsLvalueReference : false_t {};
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template<typename T> struct IsLvalueReference<T &>: true_t {};
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/* is rvalue reference */
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template<typename > struct IsRvalueReference : false_t {};
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template<typename T> struct IsRvalueReference<T &&>: true_t {};
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/* is reference */
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template<typename T> struct IsReference: IntegralConstant<bool,
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(IsLvalueReference<T>::value || IsRvalueReference<T>::value)
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> {};
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/* add lvalue reference */
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template<typename T> struct AddLvalueReference { typedef T &type; };
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template<typename T> struct AddLvalueReference<T &> { typedef T &type; };
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template<typename T> struct AddLvalueReference<T &&> { typedef T &type; };
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template<> struct AddLvalueReference<void> {
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typedef void type;
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};
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template<> struct AddLvalueReference<const void> {
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typedef const void type;
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};
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template<> struct AddLvalueReference<volatile void> {
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typedef volatile void type;
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};
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template<> struct AddLvalueReference<const volatile void> {
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typedef const volatile void type;
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};
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/* add rvalue reference */
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template<typename T> using AddRvalueReference = internal::AddRvalueReference<T>;
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/* is array */
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template<typename > struct IsArray : false_t {};
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template<typename T > struct IsArray<T[] >: true_t {};
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template<typename T, size_t N> struct IsArray<T[N]>: true_t {};
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/* result of call at compile time */
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namespace internal {
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template<typename F, typename ...A>
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inline auto result_of_invoke(F &&f, A &&...args) ->
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decltype(forward<F>(f)(forward<A>(args)...)) {
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return forward<F>(f)(forward<A>(args)...);
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}
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template<typename B, typename T, typename D>
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inline auto result_of_invoke(T B::*pmd, D &&ref) ->
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decltype(forward<D>(ref).*pmd) {
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return forward<D>(ref).*pmd;
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}
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template<typename PMD, typename P>
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inline auto result_of_invoke(PMD &&pmd, P &&ptr) ->
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decltype((*forward<P>(ptr)).*forward<PMD>(pmd)) {
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return (*forward<P>(ptr)).*forward<PMD>(pmd);
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}
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template<typename B, typename T, typename D, typename ...A>
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inline auto result_of_invoke(T B::*pmf, D &&ref, A &&...args) ->
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decltype((forward<D>(ref).*pmf)(forward<A>(args)...)) {
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return (forward<D>(ref).*pmf)(forward<A>(args)...);
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}
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template<typename PMF, typename P, typename ...A>
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inline auto result_of_invoke(PMF &&pmf, P &&ptr, A &&...args) ->
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decltype(((*forward<P>(ptr)).*forward<PMF>(pmf))(forward<A>(args)...)) {
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return ((*forward<P>(ptr)).*forward<PMF>(pmf))(forward<A>(args)...);
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}
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template<typename, typename = void>
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struct ResultOf {};
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template<typename F, typename ...A>
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struct ResultOf<F(A...), decltype(void(internal::result_of_invoke(
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declval<F>(), declval<A>()...)))> {
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using type = decltype(internal::result_of_invoke(declval<F>(),
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declval<A>()...));
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};
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}
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/* cppreference.com used for reference */
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template<typename T> struct ResultOf: internal::ResultOf<T> {};
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}
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#endif |