atomicoperations.cpp

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// The DAGFrameScheduler is a Multi-Threaded lock free and wait free scheduling library.
// © Copyright 2010 - 2016 BlackTopp Studios Inc.
/* This file is part of The DAGFrameScheduler.

    The DAGFrameScheduler is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
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*/
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*/
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#ifndef _atomic_black_ops_would_be_an_awesome_name_for_a_cheezy_game_cpp
#define _atomic_black_ops_would_be_an_awesome_name_for_a_cheezy_game_cpp

#include "atomicoperations.h"
#include "crossplatformincludes.h"

/// @file
/// @brief The implementation of simple thread safe ways to check and change a specified variable atomically.

namespace Mezzanine
{
    namespace Threading
    {
        Int32 AtomicCompareAndSwap32(Int32* VariableToChange, const Int32& OldValue, const Int32& NewValue)
        {
            #ifdef _MEZZ_THREAD_WIN32_
                return InterlockedCompareExchange((long*)VariableToChange,NewValue,OldValue);
            #else
                return __sync_val_compare_and_swap(VariableToChange,OldValue,NewValue);
            #endif
        }
/*
        // This does not appear to be supported on winxp
        Int64 AtomicCompareAndSwap64(Int64* VariableToChange, const Int64& OldValue, const Int64& NewValue)
        {
            #ifdef _MEZZ_THREAD_WIN32_
                return InterlockedCompareExchange64((long long*)VariableToChange,NewValue,OldValue);
            #else
                return __sync_val_compare_and_swap(VariableToChange,OldValue,NewValue);
            #endif
        }
*/
        Int32 AtomicAdd(Int32* VariableToChange, Int32 Value)
        {
            //while (*VariableToChange!=AtomicCompareAndSwap(VariableToChange,*VariableToChange,*VariableToChange+Value));
            //return *VariableToChange;
            #ifdef _MEZZ_THREAD_WIN32_
                return InterlockedExchangeAdd((long*)VariableToChange, Value);
            #else
                //return __sync_add_and_fetch(VariableToChange,Value);
                return __sync_fetch_and_add(VariableToChange,Value);
            #endif
        }
    }//Threading
}//Mezzanine

#endif