libostd/octa/traits.h

302 lines
9.6 KiB
C++

/* Type traits for OctaSTD.
*
* This file is part of OctaSTD. See COPYING.md for futher information.
*/
#ifndef OCTA_TRAITS_H
#define OCTA_TRAITS_H
#include <stddef.h>
#include "octa/types.h"
#include "octa/utility.h"
namespace octa {
/* removers */
template<typename T> using RemoveReference = internal::RemoveReference<T>;
template<typename T> struct RemoveConst { typedef T type; };
template<typename T> struct RemoveConst<const T> { typedef T type; };
template<typename T> struct RemoveVolatile { typedef T type; };
template<typename T> struct RemoveVolatile<volatile T> { typedef T type; };
template<typename T>
struct RemoveConstVolatile {
typedef typename RemoveVolatile<typename RemoveConst<T>::type>::type type;
};
/* integral constant */
template<typename T, T val>
struct IntegralConstant {
static constexpr const T value = val;
typedef T value_type;
typedef IntegralConstant<T, val> type;
constexpr operator value_type() const { return value; }
constexpr value_type operator()() const { return value; }
};
typedef IntegralConstant<bool, true> true_t;
typedef IntegralConstant<bool, false> false_t;
template<typename T, T val> constexpr const T IntegralConstant<T, val>::value;
/* is void */
template<typename T> struct IsVoidBase : false_t {};
template< > struct IsVoidBase<void>: true_t {};
template<typename T>
struct IsVoid: IsVoidBase<typename RemoveConstVolatile<T>::type> {};
/* is null pointer */
template<typename> struct IsNullPointerBase : false_t {};
template< > struct IsNullPointerBase<nullptr_t>: true_t {};
template<typename T>
struct IsNullPointer: IsNullPointerBase<
typename RemoveConstVolatile<T>::type
> {};
/* is integer */
template<typename T> struct IsIntegralBase: false_t {};
template<> struct IsIntegralBase<bool >: true_t {};
template<> struct IsIntegralBase<char >: true_t {};
template<> struct IsIntegralBase<uchar >: true_t {};
template<> struct IsIntegralBase<schar >: true_t {};
template<> struct IsIntegralBase<short >: true_t {};
template<> struct IsIntegralBase<ushort>: true_t {};
template<> struct IsIntegralBase<int >: true_t {};
template<> struct IsIntegralBase<uint >: true_t {};
template<> struct IsIntegralBase<long >: true_t {};
template<> struct IsIntegralBase<ulong >: true_t {};
template<> struct IsIntegralBase<llong >: true_t {};
template<> struct IsIntegralBase<ullong>: true_t {};
template<typename T>
struct IsIntegral: IsIntegralBase<typename RemoveConstVolatile<T>::type> {};
/* is floating point */
template<typename T> struct IsFloatingPointBase : false_t {};
template<> struct IsFloatingPointBase<float >: true_t {};
template<> struct IsFloatingPointBase<double >: true_t {};
template<> struct IsFloatingPointBase<ldouble>: true_t {};
template<typename T>
struct IsFloatingPoint: IsFloatingPointBase<typename RemoveConstVolatile<T>::type> {};
/* is array */
template<typename > struct IsArray : false_t {};
template<typename T > struct IsArray<T[] >: true_t {};
template<typename T, size_t N> struct IsArray<T[N]>: true_t {};
/* is pointer */
template<typename > struct IsPointerBase : false_t {};
template<typename T> struct IsPointerBase<T *>: true_t {};
template<typename T>
struct IsPointer: IsPointerBase<typename RemoveConstVolatile<T>::type> {};
/* is lvalue reference */
template<typename > struct IsLvalueReference : false_t {};
template<typename T> struct IsLvalueReference<T &>: true_t {};
/* is rvalue reference */
template<typename > struct IsRvalueReference : false_t {};
template<typename T> struct IsRvalueReference<T &&>: true_t {};
/* is enum */
template<typename T> struct IsEnum: IntegralConstant<bool, __is_enum(T)> {};
/* is union */
template<typename T> struct IsUnion: IntegralConstant<bool, __is_union(T)> {};
/* is class */
template<typename T> struct IsClass: IntegralConstant<bool, __is_class(T)> {};
/* is number */
template<typename T> struct IsNumber: IntegralConstant<bool,
(IsIntegral<T>::value || IsFloatingPoint<T>::value)
> {};
/* is pointer to member */
template<typename > struct IsMemberPointerBase: false_t {};
template<typename T, typename U>
struct IsMemberPointerBase<T U::*>: true_t {};
template<typename T>
struct IsMemberPointer: IsMemberPointerBase<
typename RemoveConstVolatile<T>::type
> {};
/* is POD: currently wrong */
template<typename T> struct IsPOD: IntegralConstant<bool,
(IsIntegral<T>::value || IsFloatingPoint<T>::value || IsPointer<T>::value)
> {};
/* type equality */
template<typename, typename> struct IsEqual : false_t {};
template<typename T > struct IsEqual<T, T>: true_t {};
/* is reference */
template<typename T> struct IsReference: IntegralConstant<bool,
(IsLvalueReference<T>::value || IsRvalueReference<T>::value)
> {};
/* add lvalue reference */
template<typename T> struct AddLvalueReference { typedef T &type; };
template<typename T> struct AddLvalueReference<T &> { typedef T &type; };
template<typename T> struct AddLvalueReference<T &&> { typedef T &type; };
template<> struct AddLvalueReference<void> {
typedef void type;
};
template<> struct AddLvalueReference<const void> {
typedef const void type;
};
template<> struct AddLvalueReference<volatile void> {
typedef volatile void type;
};
template<> struct AddLvalueReference<const volatile void> {
typedef const volatile void type;
};
/* add rvalue reference */
template<typename T> using AddRvalueReference = internal::AddRvalueReference<T>;
/* extent */
template<typename T, unsigned I = 0>
struct Extent: IntegralConstant<size_t, 0> {};
template<typename T>
struct Extent<T[], 0>: IntegralConstant<size_t, 0> {};
template<typename T, unsigned I>
struct Extent<T[], I>: IntegralConstant<size_t, Extent<T, I - 1>::value> {};
template<typename T, size_t N>
struct Extent<T[N], 0>: IntegralConstant<size_t, N> {};
template<typename T, size_t N, unsigned I>
struct Extent<T[N], I>: IntegralConstant<size_t, Extent<T, I - 1>::value> {};
/* remove extent */
template<typename T > struct RemoveExtent { typedef T type; };
template<typename T > struct RemoveExtent<T[ ]> { typedef T type; };
template<typename T, size_t N> struct RemoveExtent<T[N]> { typedef T type; };
/* remove all extents */
template<typename T> struct RemoveAllExtents { typedef T type; };
template<typename T> struct RemoveAllExtents<T[]> {
typedef typename RemoveAllExtents<T>::type type;
};
template<typename T, size_t N> struct RemoveAllExtents<T[N]> {
typedef typename RemoveAllExtents<T>::type type;
};
/* conditional */
template<bool cond, typename T, typename U>
struct Conditional {
typedef T type;
};
template<typename T, typename U>
struct Conditional<false, T, U> {
typedef U type;
};
/* result of call at compile time */
namespace internal {
template<typename F, typename ...A>
inline auto result_of_invoke(F &&f, A &&...args) ->
decltype(forward<F>(f)(forward<A>(args)...)) {
return forward<F>(f)(forward<A>(args)...);
}
template<typename B, typename T, typename D>
inline auto result_of_invoke(T B::*pmd, D &&ref) ->
decltype(forward<D>(ref).*pmd) {
return forward<D>(ref).*pmd;
}
template<typename PMD, typename P>
inline auto result_of_invoke(PMD &&pmd, P &&ptr) ->
decltype((*forward<P>(ptr)).*forward<PMD>(pmd)) {
return (*forward<P>(ptr)).*forward<PMD>(pmd);
}
template<typename B, typename T, typename D, typename ...A>
inline auto result_of_invoke(T B::*pmf, D &&ref, A &&...args) ->
decltype((forward<D>(ref).*pmf)(forward<A>(args)...)) {
return (forward<D>(ref).*pmf)(forward<A>(args)...);
}
template<typename PMF, typename P, typename ...A>
inline auto result_of_invoke(PMF &&pmf, P &&ptr, A &&...args) ->
decltype(((*forward<P>(ptr)).*forward<PMF>(pmf))(forward<A>(args)...)) {
return ((*forward<P>(ptr)).*forward<PMF>(pmf))(forward<A>(args)...);
}
template<typename, typename = void>
struct ResultOf {};
template<typename F, typename ...A>
struct ResultOf<F(A...), decltype(void(result_of_invoke(declval<F>(),
declval<A>()...)))> {
using type = decltype(result_of_invoke(declval<F>(), declval<A>()...));
};
}
/* cppreference.com used for reference */
template<typename T> struct ResultOf: internal::ResultOf<T> {};
/* enable_if */
template<bool B, typename T = void> struct enable_if {};
template<typename T> struct enable_if<true, T> { typedef T type; };
/* decay */
#if 0
template<typename T>
struct Decay {
private:
typedef typename RemoveReference<T>::type U;
public:
typedef typename Conditional<IsArray<U>::value,
typename RemoveExtent<U>::type *,
typename Conditional<IsFunction<U>::value,
typename AddPointer<U>::type,
typename RemoveConstVolatile<U>::type
>::type
>::type type;
};
#endif
}
#endif