MovieSceneComponentTypeIDs.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "EntitySystem/MovieSceneEntityIDs.h"
#include "Delegates/IntegerSequence.h"
#include "Containers/ArrayView.h"
 
namespace UE::MovieScene
{
 
namespace Private
{
    template<typename...>
    struct TComponentTypeIDsImpl;
 
    template <typename T, int Index>
    struct TComponentGetterElement{};
 
    template <int Index>
    struct TComponentGetter
    {
        template<typename Deduced>
        static FORCEINLINE TComponentTypeID<Deduced> GetImpl(const TComponentGetterElement<Deduced, Index>&, TArrayView<const FComponentTypeID> Values)
        {
            return Values[Index].template ReinterpretCast<Deduced>();
        }
 
        template<typename DerivedType>
        static FORCEINLINE auto Get(const DerivedType& In)
        {
            return GetImpl(In, In.GetTypes());
        }
    };
 
    template<>
    struct TComponentTypeIDsImpl<TIntegerSequence<int>>
    {
        void Initialize()
        {
        }
        template<int Index>
        FORCEINLINE void GetType() const
        {
        }
        FORCEINLINE static TArrayView<const FComponentTypeID> GetTypes()
        {
            return TArrayView<const FComponentTypeID>();
        }
    };
 
 
    template<typename ...T, int... Indices>
    struct TComponentTypeIDsImpl<TIntegerSequence<int, Indices...>, T...> : Private::TComponentGetterElement<T, Indices>...
    {
        template<int Index>
        FORCEINLINE auto GetType() const
        {
            static_assert(Index < sizeof...(Indices), "Unable to retrieve a component type for an invalid index");
            return Private::TComponentGetter<Index>::Get(*this);
        }
 
        FORCEINLINE FComponentTypeID GetType(int Index) const
        {
            return Values[Index];
        }
        TArrayView<const FComponentTypeID> GetTypes() const
        {
            return MakeArrayView(Values);
        }
        void Initialize(TComponentTypeID<T>... InTypes)
        {
            (..., (Values[Indices] = InTypes));
        }
 
    protected:
 
        static constexpr int32 SIZE = sizeof...(T);
        FComponentTypeID Values[SIZE];
    };
 
} // namespace Private
 
template<typename ...T>
using TComponentTypeIDs = Private::TComponentTypeIDsImpl<TMakeIntegerSequence<int, sizeof...(T)>, T...>;
 
 
} // namespace UE::MovieScene