Win32Atomics.hpp

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/*
 *  Copyright 2019-2021 Diligent Graphics LLC
 *  Copyright 2015-2019 Egor Yusov
 *  
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *  
 *      http://www.apache.org/licenses/LICENSE-2.0
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#pragma once
 
struct WindowsAtomics
{
    // Use windows-specific atomics. Standard atomic eventually call
    // the same functions, but introduce significant overhead
    using Long        = long;
    using AtomicLong  = volatile long;
    using Int64       = long long;
    using AtomicInt64 = volatile long long;
 
    // The function returns the resulting INCREMENTED value.
    static Long  AtomicIncrement(AtomicLong& Val);
    static Int64 AtomicIncrement(AtomicInt64& Val);
 
    // The function returns the resulting DECREMENTED value.
    static Long  AtomicDecrement(AtomicLong& Val);
    static Int64 AtomicDecrement(AtomicInt64& Val);
 
    // The function compares the Destination value with the Comparand value. If the Destination value is equal
    // to the Comparand value, the Exchange value is stored in the address specified by Destination.
    // Otherwise, no operation is performed.
    // The function returns the initial value of the Destination parameter
    static Long AtomicCompareExchange(AtomicLong& Destination, Long Exchange, Long Comparand);
 
    static Long  AtomicAdd(AtomicLong& Destination, Long Val);
    static Int64 AtomicAdd(AtomicInt64& Destination, Int64 Val);
};