ThreadSafeCounter.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "CoreTypes.h"
#include "HAL/PlatformAtomics.h"
 
// DEPRECATED. Please use `std::atomic<int32>`.
 
class FThreadSafeCounter
{
public:
    using IntegerType = int32;
 
    FThreadSafeCounter(int32 Value = 0)
    {
#if USING_THREAD_SANITISER
        FPlatformAtomics::AtomicStore(&Counter, Value);
#else
        Counter = Value;
#endif
    }
 
    FThreadSafeCounter( const FThreadSafeCounter& Other )
        : FThreadSafeCounter(Other.GetValue())
    {
    }
 
    int32 Increment()
    {
        return FPlatformAtomics::InterlockedIncrement(&Counter);
    }
 
    int32 Add( int32 Amount )
    {
        return FPlatformAtomics::InterlockedAdd(&Counter, Amount);
    }
 
    int32 Decrement()
    {
        return FPlatformAtomics::InterlockedDecrement(&Counter);
    }
 
    int32 Subtract( int32 Amount )
    {
        return FPlatformAtomics::InterlockedAdd(&Counter, -Amount);
    }
 
    int32 Set( int32 Value )
    {
        return FPlatformAtomics::InterlockedExchange(&Counter, Value);
    }
 
    int32 Reset()
    {
        return Set(0);
    }
 
    int32 GetValue() const
    {
        return FPlatformAtomics::AtomicRead(&Counter);
    }
 
private:
 
    void operator=(const FThreadSafeCounter& Other) = delete;
 
    volatile int32 Counter;
};