StructUtilsTypes.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include <type_traits>
#include "UObject/Class.h"
#include "StructUtils/StructUtilsMacros.h"
 
#define UE_API COREUOBJECT_API
 
struct FSharedStruct;
struct FConstSharedStruct;
struct FStructView;
struct FConstStructView;
struct FInstancedStruct;
class FReferenceCollector;
class UUserDefinedStruct;
 
namespace UE::StructUtils
{
    extern UE_API uint32 GetStructCrc32(const UScriptStruct& ScriptStruct, const uint8* StructMemory, const uint32 CRC = 0);
    extern UE_API uint32 GetStructCrc32(const FStructView& StructView, const uint32 CRC = 0);
    extern UE_API uint32 GetStructCrc32(const FConstStructView& StructView, const uint32 CRC = 0);
    extern UE_API uint32 GetStructCrc32(const FSharedStruct& SharedView, const uint32 CRC = 0);
    extern UE_API uint32 GetStructCrc32(const FConstSharedStruct& SharedView, const uint32 CRC = 0);
 
    extern UE_API uint32 GetStructInstanceCrc32(const UScriptStruct& ScriptStruct, const uint8* StructMemory, const uint32 CRC = 0);
    extern UE_API uint32 GetStructInstanceCrc32(const FStructView& StructView, const uint32 CRC = 0);
    extern UE_API uint32 GetStructInstanceCrc32(const FConstStructView& StructView, const uint32 CRC = 0);
    extern UE_API uint32 GetStructInstanceCrc32(const FSharedStruct& SharedView, const uint32 CRC = 0);
    extern UE_API uint32 GetStructInstanceCrc32(const FConstSharedStruct& SharedView, const uint32 CRC = 0);
 
    extern UE_API uint64 GetStructHash64(const UScriptStruct& ScriptStruct, const uint8* StructMemory);
    extern UE_API uint64 GetStructHash64(const FStructView& StructView);
    extern UE_API uint64 GetStructHash64(const FConstStructView& StructView);
    extern UE_API uint64 GetStructHash64(const FSharedStruct& SharedView);
    extern UE_API uint64 GetStructHash64(const FConstSharedStruct& SharedView);
 
    template <typename T>
    auto* GetAsUStruct()
    {
        if constexpr (std::is_base_of_v<UObject, T>)
        {
            return T::StaticClass();
        }
        else
        {
            return T::StaticStruct();
        }
    }
 
    template<typename T>
    inline constexpr bool TIsSharedInstancedOrViewStruct_V = std::is_same_v<FStructView, T>
        || std::is_same_v<FConstStructView, T>
        || std::is_same_v<FSharedStruct, T>
        || std::is_same_v<FConstSharedStruct, T>
        || std::is_same_v<FInstancedStruct, T>;
}
 
/* Predicate useful to find a struct of a specific type in an container */
struct FStructTypeEqualOperator
{
    const UScriptStruct* TypePtr;
 
    FStructTypeEqualOperator(const UScriptStruct* InTypePtr)
        : TypePtr(InTypePtr)
    {
    }
 
    template <typename T>
        requires (UE::StructUtils::TIsSharedInstancedOrViewStruct_V<T>)
    FStructTypeEqualOperator(const T& Struct)
        : TypePtr(Struct.GetScriptStruct())
    {
    }
 
    template <typename T>
        requires (UE::StructUtils::TIsSharedInstancedOrViewStruct_V<T>)
    bool operator()(const T& Struct) const
    {
        return Struct.GetScriptStruct() == TypePtr;
    }
};
 
struct FScriptStructSortOperator
{
    template <typename T>
    bool operator()(const T& A, const T& B) const
    {
        return (A.GetStructureSize() > B.GetStructureSize())
            || (A.GetStructureSize() == B.GetStructureSize() && B.GetFName().FastLess(A.GetFName()));
    }
};
 
struct FStructTypeSortOperator
{
    template <typename T>
        requires (UE::StructUtils::TIsSharedInstancedOrViewStruct_V<T>)
    bool operator()(const T& A, const T& B) const
    {
        const UScriptStruct* AScriptStruct = A.GetScriptStruct();
        const UScriptStruct* BScriptStruct = B.GetScriptStruct();
        if (!AScriptStruct)
        {
            return true;
        }
        else if (!BScriptStruct)
        {
            return false;
        }
        return FScriptStructSortOperator()(*AScriptStruct, *BScriptStruct);
    }
};
 
#if WITH_EDITOR
namespace UE::StructUtils::Private
{
    // Private structs used during user defined struct reinstancing.
    struct FStructureToReinstantiateScope
    {
        UE_API explicit FStructureToReinstantiateScope(const UUserDefinedStruct* StructureToReinstantiate);
        UE_API ~FStructureToReinstantiateScope();
    private:
        const UUserDefinedStruct* OldStructureToReinstantiate = nullptr;
    };
 
    struct FCurrentReinstantiationOuterObjectScope
    {
        UE_API explicit FCurrentReinstantiationOuterObjectScope(UObject* CurrentReinstantiateOuterObject);
        UE_API ~FCurrentReinstantiationOuterObjectScope();
    private:
        UObject* OldCurrentReinstantiateOuterObject = nullptr;
    };
 
    extern UE_API const UUserDefinedStruct* GetStructureToReinstantiate();
    extern UE_API UObject* GetCurrentReinstantiationOuterObject();
};
#endif // WITH_EDITOR
 
#undef UE_API