LumenUniqueList.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
/*=============================================================================
    LumenUniqueList.h:
=============================================================================*/
 
#pragma once
 
#include "CoreMinimal.h"
#include "Engine/EngineTypes.h"
#include "Experimental/Containers/SherwoodHashTable.h"
 
template <typename ElementType, typename Allocator>
struct TSparseUniqueList
{
    void Add(ElementType Element)
    {
        bool bIsAlreadyInSet = false;
        Set.Add(Element, &bIsAlreadyInSet);
        if (!bIsAlreadyInSet)
        {
            Array.Add(Element);
        }
    }
 
    TArray<ElementType, Allocator> Array;
    Experimental::TSherwoodSet<ElementType> Set;
};
 
struct FUniqueIndexList
{
public:
    void Add(int32 Index)
    {
        if (Index + 1 > IndicesMarkedToUpdate.Num())
        {
            const int32 NewSize = Align(Index + 1, 64);
            IndicesMarkedToUpdate.Add(0, NewSize - IndicesMarkedToUpdate.Num());
        }
 
        // Make sure we aren't updating same index multiple times
        if (!IndicesMarkedToUpdate[Index])
        {
            Indices.Add(Index);
            IndicesMarkedToUpdate[Index] = true;
        }
    }
 
    int32 Num() const
    {
        return Indices.Num();
    }
 
    void Reset()
    {
        Indices.Reset();
        IndicesMarkedToUpdate.Reset();
    }
 
    void Empty(int32 Slack)
    {
        Indices.Empty(Slack);
        IndicesMarkedToUpdate.Reset();
    }
 
    // Iterate over indices
    auto begin() const { return Indices.begin(); }
    auto end() const { return Indices.end(); }
 
 
private:
 
    TArray<int32> Indices;
    TBitArray<> IndicesMarkedToUpdate;
};