refactor(*): replaces template class type traits with C++20 at all
This commit is contained in:
@ -13,35 +13,83 @@ NAMESPACE_REDCRAFT_BEGIN
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NAMESPACE_MODULE_BEGIN(Redcraft)
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NAMESPACE_MODULE_BEGIN(Utility)
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template <typename... Types> requires (true && ... && CDestructible<Types>)
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struct TVariant;
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NAMESPACE_PRIVATE_BEGIN
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template <typename T, typename... Types>
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struct TVariantAlternativeIndex;
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template <typename T > struct TIsTVariant : FFalse { };
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template <typename... Types> struct TIsTVariant<TVariant<Types...>> : FTrue { };
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template <typename TupleType>
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struct TVariantNumImpl;
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template <typename... Types>
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struct TVariantNumImpl<TVariant<Types...>> : TConstant<size_t, sizeof...(Types)> { };
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template <typename... Types>
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struct TVariantNumImpl<const TVariant<Types...>> : TConstant<size_t, sizeof...(Types)> { };
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template <typename... Types>
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struct TVariantNumImpl<volatile TVariant<Types...>> : TConstant<size_t, sizeof...(Types)> { };
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template <typename... Types>
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struct TVariantNumImpl<const volatile TVariant<Types...>> : TConstant<size_t, sizeof...(Types)> { };
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template <typename T, typename TupleType>
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struct TVariantIndexImpl;
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template <typename T, typename U, typename... Types>
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struct TVariantAlternativeIndex<T, U, Types...>
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: TConstant<size_t, CSameAs<T, U> ? 0 : (TVariantAlternativeIndex<T, Types...>::Value == INDEX_NONE
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? INDEX_NONE : TVariantAlternativeIndex<T, Types...>::Value + 1)>
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{ };
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template <typename T>
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struct TVariantAlternativeIndex<T> : TConstant<size_t, INDEX_NONE> { };
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template <size_t I, typename... Types>
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struct TVariantAlternativeType;
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template <size_t I, typename T, typename... Types>
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struct TVariantAlternativeType<I, T, Types...>
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struct TVariantIndexImpl<T, TVariant<U, Types...>> : TConstant<size_t, TVariantIndexImpl<T, TVariant<Types...>>::Value + 1>
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{
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static_assert(I < sizeof...(Types) + 1, "Variant type index is invalid");
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using Type = TVariantAlternativeType<I - 1, Types...>::Type;
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static_assert(sizeof...(Types) != 0, "Non-existent types in variant");
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};
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template <typename T, typename... Types>
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struct TVariantAlternativeType<0, T, Types...> { using Type = T; };
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struct TVariantIndexImpl<T, TVariant<T, Types...>> : TConstant<size_t, 0>
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{
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static_assert((true && ... && !CSameAs<T, Types>), "Duplicate type in variant");
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};
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template <typename T>
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struct TVariantIndexImpl<T, TVariant<>> : TConstant<size_t, INDEX_NONE> { };
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template <typename T, typename... Types>
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struct TVariantIndexImpl<T, const TVariant<Types...>> : TVariantIndexImpl<T, TVariant<Types...>> { };
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template <typename T, typename... Types>
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struct TVariantIndexImpl<T, volatile TVariant<Types...>> : TVariantIndexImpl<T, TVariant<Types...>> { };
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template <typename T, typename... Types>
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struct TVariantIndexImpl<T, const volatile TVariant<Types...>> : TVariantIndexImpl<T, TVariant<Types...>> { };
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template <size_t I, typename TupleType>
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struct TVariantAlternativeImpl;
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template <size_t I, typename T, typename... Types>
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struct TVariantAlternativeImpl<I, TVariant<T, Types...>>
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{
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static_assert(I < sizeof...(Types) + 1, "Invalid index in variant");
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using Type = TVariantAlternativeImpl<I - 1, TVariant<Types...>>::Type;
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};
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template <typename T, typename... Types>
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struct TVariantAlternativeImpl<0, TVariant<T, Types...>> { using Type = T; };
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template <size_t I, typename... Types>
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struct TVariantAlternativeImpl<I, TVariant<Types...>> { };
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template <>
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struct TVariantAlternativeType<0> { };
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struct TVariantAlternativeImpl<0, TVariant<>> { };
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template <size_t I, typename... Types>
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struct TVariantAlternativeImpl<I, const TVariant<Types...>> { using Type = TAddConst<typename TVariantAlternativeImpl<I, TVariant<Types...>>::Type>; };
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template <size_t I, typename... Types>
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struct TVariantAlternativeImpl<I, volatile TVariant<Types...>> { using Type = TAddVolatile<typename TVariantAlternativeImpl<I, TVariant<Types...>>::Type>; };
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template <size_t I, typename... Types>
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struct TVariantAlternativeImpl<I, const volatile TVariant<Types...>> { using Type = TAddCV<typename TVariantAlternativeImpl<I, TVariant<Types...>>::Type>; };
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template <typename T, typename... Types>
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struct TVariantSelectedType;
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@ -78,14 +126,21 @@ struct TVariantSelectedType<T>
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NAMESPACE_PRIVATE_END
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template <typename... Types> requires (true && ... && CDestructible<Types>) && (sizeof...(Types) < 0xFF)
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template <typename T>
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concept CTVariant = NAMESPACE_PRIVATE::TIsTVariant<T>::Value;
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template <typename VariantType>
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inline constexpr size_t TVariantNum = NAMESPACE_PRIVATE::TVariantNumImpl<VariantType>::Value;
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template <typename T, typename VariantType>
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inline constexpr size_t TVariantIndex = NAMESPACE_PRIVATE::TVariantIndexImpl<T, VariantType>::Value;
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template <size_t I, typename VariantType>
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using TVariantAlternative = typename NAMESPACE_PRIVATE::TVariantAlternativeImpl<I, VariantType>::Type;
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template <typename... Types> requires (true && ... && CDestructible<Types>)
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struct TVariant
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{
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static constexpr size_t AlternativeSize = sizeof...(Types);
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template <size_t I> struct TAlternativeType : NAMESPACE_PRIVATE::TVariantAlternativeType<I, Types...> { };
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template <typename T> struct TAlternativeIndex : NAMESPACE_PRIVATE::TVariantAlternativeIndex<T, Types...> { };
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constexpr TVariant() : TypeIndex(0xFF) { };
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constexpr TVariant(FInvalid) : TVariant() { };
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@ -102,19 +157,18 @@ struct TVariant
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if (IsValid()) MoveConstructImpl[InValue.GetIndex()](&Value, &InValue.Value);
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}
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template <size_t I, typename... ArgTypes> requires (I < AlternativeSize)
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&& CConstructibleFrom<typename TAlternativeType<I>::Type, ArgTypes...>
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template <size_t I, typename... ArgTypes> requires (I < sizeof...(Types))
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&& CConstructibleFrom<TVariantAlternative<I, TVariant<Types...>>, ArgTypes...>
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constexpr explicit TVariant(TInPlaceIndex<I>, ArgTypes&&... Args)
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: TypeIndex(I)
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{
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using SelectedType = typename TAlternativeType<I>::Type;
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using SelectedType = TVariantAlternative<I, TVariant<Types...>>;
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new(&Value) SelectedType(Forward<ArgTypes>(Args)...);
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}
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template <typename T, typename... ArgTypes> requires (TAlternativeIndex<T>::Value != INDEX_NONE)
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&& CConstructibleFrom<typename TAlternativeType<TAlternativeIndex<T>::Value>::Type, ArgTypes...>
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template <typename T, typename... ArgTypes> requires CConstructibleFrom<T, ArgTypes...>
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constexpr explicit TVariant(TInPlaceType<T>, ArgTypes&&... Args)
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: TVariant(InPlaceIndex<TAlternativeIndex<T>::Value>, Forward<ArgTypes>(Args)...)
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: TVariant(InPlaceIndex<TVariantIndex<T, TVariant<Types...>>>, Forward<ArgTypes>(Args)...)
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{ }
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template <typename T> requires NAMESPACE_PRIVATE::TVariantSelectedType<TRemoveReference<T>, Types...>::Value
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@ -175,35 +229,34 @@ struct TVariant
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{
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using SelectedType = typename NAMESPACE_PRIVATE::TVariantSelectedType<TRemoveReference<T>, Types...>::Type;
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if (GetIndex() == TAlternativeIndex<SelectedType>::Value) GetValue<SelectedType>() = Forward<T>(InValue);
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if (GetIndex() == TVariantIndex<SelectedType, TVariant<Types...>>) GetValue<SelectedType>() = Forward<T>(InValue);
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else
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{
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Reset();
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new(&Value) SelectedType(Forward<T>(InValue));
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TypeIndex = TAlternativeIndex<SelectedType>::Value;
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TypeIndex = TVariantIndex<SelectedType, TVariant<Types...>>;
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}
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return *this;
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}
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template <size_t I, typename... ArgTypes> requires (I < AlternativeSize)
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&& CConstructibleFrom<typename TAlternativeType<I>::Type, ArgTypes...>
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constexpr typename TAlternativeType<I>::Type& Emplace(ArgTypes&&... Args)
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template <size_t I, typename... ArgTypes> requires (I < sizeof...(Types))
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&& CConstructibleFrom<TVariantAlternative<I, TVariant<Types...>>, ArgTypes...>
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constexpr TVariantAlternative<I, TVariant<Types...>>& Emplace(ArgTypes&&... Args)
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{
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Reset();
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using SelectedType = typename TAlternativeType<I>::Type;
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using SelectedType = TVariantAlternative<I, TVariant<Types...>>;
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SelectedType* Result = new(&Value) SelectedType(Forward<ArgTypes>(Args)...);
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TypeIndex = I;
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return *Result;
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}
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template <typename T, typename... ArgTypes> requires (TAlternativeIndex<T>::Value != INDEX_NONE)
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&& CConstructibleFrom<typename TAlternativeType<TAlternativeIndex<T>::Value>::Type, ArgTypes...>
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template <typename T, typename... ArgTypes> requires CConstructibleFrom<T, ArgTypes...>
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constexpr T& Emplace(ArgTypes&&... Args)
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{
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return Emplace<TAlternativeIndex<T>::Value>(Forward<ArgTypes>(Args)...);
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return Emplace<TVariantIndex<T, TVariant<Types...>>>(Forward<ArgTypes>(Args)...);
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}
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constexpr const type_info& GetTypeInfo() const { return IsValid() ? *TypeInfos[GetIndex()] : typeid(void); }
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@ -212,24 +265,24 @@ struct TVariant
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constexpr bool IsValid() const { return TypeIndex != 0xFF; }
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constexpr explicit operator bool() const { return TypeIndex != 0xFF; }
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template <size_t I> constexpr bool HoldsAlternative() const { return IsValid() ? GetIndex() == I : false; }
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template <typename T> constexpr bool HoldsAlternative() const { return IsValid() ? GetIndex() == TAlternativeIndex<T>::Value : false; }
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template <size_t I> constexpr bool HoldsAlternative() const { return IsValid() ? GetIndex() == I : false; }
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template <typename T> constexpr bool HoldsAlternative() const { return IsValid() ? GetIndex() == TVariantIndex<T, TVariant<Types...>> : false; }
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template <size_t I> requires (I < AlternativeSize) constexpr typename TAlternativeType<I>::Type& GetValue() & { checkf(HoldsAlternative<I>(), TEXT("It is an error to call GetValue() on an wrong TVariant. Please either check HoldsAlternative() or use Get(DefaultValue) instead.")); return *reinterpret_cast< TAlternativeType<I>::Type*>(&Value); }
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template <size_t I> requires (I < AlternativeSize) constexpr typename TAlternativeType<I>::Type&& GetValue() && { checkf(HoldsAlternative<I>(), TEXT("It is an error to call GetValue() on an wrong TVariant. Please either check HoldsAlternative() or use Get(DefaultValue) instead.")); return MoveTemp(*reinterpret_cast< TAlternativeType<I>::Type*>(&Value)); }
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template <size_t I> requires (I < AlternativeSize) constexpr const typename TAlternativeType<I>::Type& GetValue() const& { checkf(HoldsAlternative<I>(), TEXT("It is an error to call GetValue() on an wrong TVariant. Please either check HoldsAlternative() or use Get(DefaultValue) instead.")); return *reinterpret_cast<const TAlternativeType<I>::Type*>(&Value); }
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template <size_t I> requires (I < AlternativeSize) constexpr const typename TAlternativeType<I>::Type&& GetValue() const&& { checkf(HoldsAlternative<I>(), TEXT("It is an error to call GetValue() on an wrong TVariant. Please either check HoldsAlternative() or use Get(DefaultValue) instead.")); return MoveTemp(*reinterpret_cast<const TAlternativeType<I>::Type*>(&Value)); }
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template <size_t I> requires (I < sizeof...(Types)) constexpr decltype(auto) GetValue() & { checkf(HoldsAlternative<I>(), TEXT("It is an error to call GetValue() on an wrong TVariant. Please either check HoldsAlternative() or use Get(DefaultValue) instead.")); return *reinterpret_cast< TVariantAlternative<I, TVariant<Types...>>*>(&Value); }
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template <size_t I> requires (I < sizeof...(Types)) constexpr decltype(auto) GetValue() && { checkf(HoldsAlternative<I>(), TEXT("It is an error to call GetValue() on an wrong TVariant. Please either check HoldsAlternative() or use Get(DefaultValue) instead.")); return MoveTemp(*reinterpret_cast< TVariantAlternative<I, TVariant<Types...>>*>(&Value)); }
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template <size_t I> requires (I < sizeof...(Types)) constexpr decltype(auto) GetValue() const& { checkf(HoldsAlternative<I>(), TEXT("It is an error to call GetValue() on an wrong TVariant. Please either check HoldsAlternative() or use Get(DefaultValue) instead.")); return *reinterpret_cast<const TVariantAlternative<I, TVariant<Types...>>*>(&Value); }
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template <size_t I> requires (I < sizeof...(Types)) constexpr decltype(auto) GetValue() const&& { checkf(HoldsAlternative<I>(), TEXT("It is an error to call GetValue() on an wrong TVariant. Please either check HoldsAlternative() or use Get(DefaultValue) instead.")); return MoveTemp(*reinterpret_cast<const TVariantAlternative<I, TVariant<Types...>>*>(&Value)); }
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template <typename T> requires (TAlternativeIndex<T>::Value != INDEX_NONE) constexpr T& GetValue() & { checkf(HoldsAlternative<T>(), TEXT("It is an error to call GetValue() on an wrong TVariant. Please either check HoldsAlternative() or use Get(DefaultValue) instead.")); return *reinterpret_cast< T*>(&Value); }
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template <typename T> requires (TAlternativeIndex<T>::Value != INDEX_NONE) constexpr T&& GetValue() && { checkf(HoldsAlternative<T>(), TEXT("It is an error to call GetValue() on an wrong TVariant. Please either check HoldsAlternative() or use Get(DefaultValue) instead.")); return MoveTemp(*reinterpret_cast< T*>(&Value)); }
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template <typename T> requires (TAlternativeIndex<T>::Value != INDEX_NONE) constexpr const T& GetValue() const& { checkf(HoldsAlternative<T>(), TEXT("It is an error to call GetValue() on an wrong TVariant. Please either check HoldsAlternative() or use Get(DefaultValue) instead.")); return *reinterpret_cast<const T*>(&Value); }
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template <typename T> requires (TAlternativeIndex<T>::Value != INDEX_NONE) constexpr const T&& GetValue() const&& { checkf(HoldsAlternative<T>(), TEXT("It is an error to call GetValue() on an wrong TVariant. Please either check HoldsAlternative() or use Get(DefaultValue) instead.")); return MoveTemp(*reinterpret_cast<const T*>(&Value)); }
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template <typename T> constexpr decltype(auto) GetValue() & { checkf(HoldsAlternative<T>(), TEXT("It is an error to call GetValue() on an wrong TVariant. Please either check HoldsAlternative() or use Get(DefaultValue) instead.")); return *reinterpret_cast< T*>(&Value); }
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template <typename T> constexpr decltype(auto) GetValue() && { checkf(HoldsAlternative<T>(), TEXT("It is an error to call GetValue() on an wrong TVariant. Please either check HoldsAlternative() or use Get(DefaultValue) instead.")); return MoveTemp(*reinterpret_cast< T*>(&Value)); }
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template <typename T> constexpr decltype(auto) GetValue() const& { checkf(HoldsAlternative<T>(), TEXT("It is an error to call GetValue() on an wrong TVariant. Please either check HoldsAlternative() or use Get(DefaultValue) instead.")); return *reinterpret_cast<const T*>(&Value); }
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template <typename T> constexpr decltype(auto) GetValue() const&& { checkf(HoldsAlternative<T>(), TEXT("It is an error to call GetValue() on an wrong TVariant. Please either check HoldsAlternative() or use Get(DefaultValue) instead.")); return MoveTemp(*reinterpret_cast<const T*>(&Value)); }
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template <size_t I> requires (I < AlternativeSize) constexpr typename TAlternativeType<I>::Type& Get( typename TAlternativeType<I>::Type& DefaultValue) & { return HoldsAlternative<I>() ? GetValue<I>() : DefaultValue; }
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template <size_t I> requires (I < AlternativeSize) constexpr const typename TAlternativeType<I>::Type& Get(const typename TAlternativeType<I>::Type& DefaultValue) const& { return HoldsAlternative<I>() ? GetValue<I>() : DefaultValue; }
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template <size_t I> requires (I < sizeof...(Types)) constexpr decltype(auto) Get( TVariantAlternative<I, TVariant<Types...>>& DefaultValue) & { return HoldsAlternative<I>() ? GetValue<I>() : DefaultValue; }
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template <size_t I> requires (I < sizeof...(Types)) constexpr decltype(auto) Get(const TVariantAlternative<I, TVariant<Types...>>& DefaultValue) const& { return HoldsAlternative<I>() ? GetValue<I>() : DefaultValue; }
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template <typename T> requires (TAlternativeIndex<T>::Value != INDEX_NONE) constexpr T& Get(T& DefaultValue)& { return HoldsAlternative<T>() ? GetValue<T>() : DefaultValue; }
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template <typename T> requires (TAlternativeIndex<T>::Value != INDEX_NONE) constexpr const T& Get(const T& DefaultValue) const& { return HoldsAlternative<T>() ? GetValue<T>() : DefaultValue; }
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template <typename T> constexpr decltype(auto) Get( T& DefaultValue) & { return HoldsAlternative<T>() ? GetValue<T>() : DefaultValue; }
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template <typename T> constexpr decltype(auto) Get(const T& DefaultValue) const& { return HoldsAlternative<T>() ? GetValue<T>() : DefaultValue; }
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template <typename F> requires (true && ... && CInvocable<F, Types>)
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FORCEINLINE decltype(auto) Visit(F&& Func) &
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@ -409,24 +462,6 @@ constexpr bool operator==(const TVariant<Types...>& LHS, FInvalid)
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return !LHS.IsValid();
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}
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NAMESPACE_PRIVATE_BEGIN
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template <typename T > struct TIsTVariant : FFalse { };
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template <typename... Types> struct TIsTVariant<TVariant<Types...>> : FTrue { };
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NAMESPACE_PRIVATE_END
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template <typename T> concept CTVariant = NAMESPACE_PRIVATE::TIsTVariant<T>::Value;
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template <typename VariantType> requires CTVariant<TRemoveCVRef<VariantType>>
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struct TVariantAlternativeSize : TConstant<size_t, VariantType::AlternativeSize> { };
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template <size_t I, typename VariantType> requires CTVariant<TRemoveCVRef<VariantType>>
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struct TVariantAlternativeType { using Type = TCopyCV<TRemoveReference<VariantType>, typename TRemoveCVRef<VariantType>::template TAlternativeType<I>::Type>; };
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template <typename T, typename VariantType> requires CTVariant<TRemoveCVRef<VariantType>>
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struct TVariantAlternativeIndex : VariantType::template TAlternativeIndex<T> { };
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NAMESPACE_MODULE_END(Utility)
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NAMESPACE_MODULE_END(Redcraft)
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NAMESPACE_REDCRAFT_END
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