SetUtilities.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreTypes.h"
#include "Serialization/MemoryLayout.h"
#include "Templates/MemoryOps.h"
#include "Templates/Tuple.h"
#include "Templates/UnrealTypeTraits.h"
 
template <typename T> struct TIsTSet { enum { Value = false }; };
 
template<typename ElementType,typename InKeyType,bool bInAllowDuplicateKeys = false>
struct BaseKeyFuncs
{
    typedef InKeyType KeyType;
    typedef typename TCallTraits<InKeyType>::ParamType KeyInitType;
    typedef typename TCallTraits<ElementType>::ParamType ElementInitType;
 
    enum { bAllowDuplicateKeys = bInAllowDuplicateKeys };
};
 
template<typename ElementType,bool bInAllowDuplicateKeys /*= false*/>
struct DefaultKeyFuncs : BaseKeyFuncs<ElementType,ElementType,bInAllowDuplicateKeys>
{
    typedef typename TTypeTraits<ElementType>::ConstPointerType KeyInitType;
    typedef typename TCallTraits<ElementType>::ParamType ElementInitType;
 
    [[nodiscard]] static UE_FORCEINLINE_HINT KeyInitType GetSetKey(ElementInitType Element)
    {
        return Element;
    }
 
    [[nodiscard]] static UE_FORCEINLINE_HINT bool Matches(KeyInitType A, KeyInitType B)
    {
        return A == B;
    }
 
    template<typename ComparableKey>
    [[nodiscard]] static UE_FORCEINLINE_HINT bool Matches(KeyInitType A, ComparableKey B)
    {
        return A == B;
    }
 
    [[nodiscard]] static UE_FORCEINLINE_HINT uint32 GetKeyHash(KeyInitType Key)
    {
        return GetTypeHash(Key);
    }
 
    template<typename ComparableKey>
    [[nodiscard]] static UE_FORCEINLINE_HINT uint32 GetKeyHash(ComparableKey Key)
    {
        return GetTypeHash(Key);
    }
};
 
template<typename T>
inline void MoveByRelocate(T& A, T& B)
{
    // Destruct the previous value of A.
    A.~T();
 
    // Relocate B into the 'hole' left by the destruction of A, leaving a hole in B instead.
    RelocateConstructItems<T>(&A, &B, 1);
}
 
class FSetElementId
{
public:
    constexpr UE_FORCEINLINE_HINT FSetElementId() = default;
 
    [[nodiscard]] UE_FORCEINLINE_HINT bool IsValidId() const
    {
        return Index != INDEX_NONE;
    }
 
    [[nodiscard]] UE_FORCEINLINE_HINT friend bool operator==(const FSetElementId& A, const FSetElementId& B)
    {
        return A.Index == B.Index;
    }
    [[nodiscard]] UE_FORCEINLINE_HINT friend bool operator!=(const FSetElementId& A, const FSetElementId& B)
    {
        return A.Index != B.Index;
    }
 
    [[nodiscard]] constexpr UE_FORCEINLINE_HINT int32 AsInteger() const
    {
        return Index;
    }
 
    [[nodiscard]] UE_FORCEINLINE_HINT static FSetElementId FromInteger(int32 Integer)
    {
        return FSetElementId(Integer);
    }
 
private:
    int32 Index = INDEX_NONE;
 
    [[nodiscard]] UE_FORCEINLINE_HINT explicit FSetElementId(int32 InIndex)
    : Index(InIndex)
    {
    }
};
 
// This is just an int32
DECLARE_INTRINSIC_TYPE_LAYOUT(FSetElementId);