// Copyright Epic Games, Inc. All Rights Reserved.

/*=============================================================================
        UnObjAllocator.h: Unreal object allocation
=============================================================================*/

#pragma once

#include "CoreMinimal.h"

class COREUOBJECT_API FUObjectAllocator
{
public:
    /**
     * Constructor, initializes to no permanent object pool
     */
    FUObjectAllocator(): PermanentObjectPoolSize(0),
                         PermanentObjectPool(NULL),
                         PermanentObjectPoolTail(NULL),
                         PermanentObjectPoolExceededTail(NULL)
    {
    }

    /**
     * Allocates and initializes the permanent object pool
     *
     * @param InPermanentObjectPoolSize size of permanent object pool
     */
    void AllocatePermanentObjectPool(int32 InPermanentObjectPoolSize);

    /**
     * Prints a debugf message to allow tuning
     */
    void BootMessage();

    /**
     * Checks whether object is part of permanent object pool.
     *
     * @param Object object to test as a member of permanent object pool
     * @return true if object is part of permanent object pool, false otherwise
     */
    FORCEINLINE bool ResidesInPermanentPool(const UObjectBase* Object) const
    {
        return ((const uint8*)Object >= PermanentObjectPool) && ((const uint8*)Object < PermanentObjectPoolTail);
    }

    /**
     * Allocates a UObjectBase from the free store or the permanent object pool
     *
     * @param Size size of uobject to allocate
     * @param Alignment alignment of uobject to allocate
     * @param bAllowPermanent if true, allow allocation in the permanent object pool, if it fits
     * @return newly allocated UObjectBase (not really a UObjectBase yet, no constructor like thing has been called).
     */
    UObjectBase* AllocateUObject(int32 Size, int32 Alignment, bool bAllowPermanent);

    /**
     * Returns a UObjectBase to the free store, unless it is in the permanent object pool
     *
     * @param Object object to free
     */
    void FreeUObject(UObjectBase* Object) const;

private:
    /** Size in bytes of pool for objects disregarded for GC.								*/
    int32 PermanentObjectPoolSize;
    /** Begin of pool for objects disregarded for GC.										*/
    uint8* PermanentObjectPool;
    /** Current position in pool for objects disregarded for GC.							*/
    uint8* PermanentObjectPoolTail;
    /** Tail that exceeded the size of the permanent object pool, >= PermanentObjectPoolTail.		*/
    uint8* PermanentObjectPoolExceededTail;
};

/** Global UObjectBase allocator							*/
extern COREUOBJECT_API FUObjectAllocator GUObjectAllocator;