MemoryLayoutUtil.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "Math/UnrealMathUtility.h"
#include "Templates/AlignmentTemplates.h"
 
struct FMemoryLayoutUtil
{
    struct FLayout
    {
        SIZE_T CurrentOffset = 0;
        SIZE_T MaxAlignment = 1;
    };
 
    struct FOffsetAndSize
    {
        SIZE_T Offset;
        SIZE_T Size;
    };
 
    struct FSizeAndAlignment
    {
        SIZE_T Size = 0;
        SIZE_T Alignment = 0;
    };
 
    static SIZE_T GetTotalSizeIncludingAlignment(const FLayout& Layout) { return Align(Layout.CurrentOffset, Layout.MaxAlignment); }
 
    static void AddToLayout(FLayout& Layout, FOffsetAndSize& OutOffsetAndSize, SIZE_T ItemSize, SIZE_T ItemAlignment, SIZE_T ItemCount)
    {
        const SIZE_T CurrentAlignedOffset = Align(Layout.CurrentOffset, ItemAlignment);
        const SIZE_T TotalItemSize = ItemSize * ItemCount;
 
        OutOffsetAndSize.Offset = CurrentAlignedOffset;
        OutOffsetAndSize.Size = TotalItemSize;
 
        Layout.CurrentOffset = CurrentAlignedOffset + TotalItemSize;
        Layout.MaxAlignment = FMath::Max<SIZE_T>(ItemAlignment, Layout.MaxAlignment);
    }
 
    template<typename T>
    static void AddToLayout(FLayout& Layout, FOffsetAndSize& OutOffsetAndSize, SIZE_T Count) { AddToLayout(Layout, OutOffsetAndSize, sizeof(T), alignof(T), Count); }
};