mutex.cuh

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#pragma once

#if (__cplusplus > 199711L) || (defined(_MSC_VER) && _MSC_VER >= 1800)
    #include <mutex>
#else
    #if defined(_WIN32) || defined(_WIN64)
        #include <intrin.h>

        #define WIN32_LEAN_AND_MEAN
        #define NOMINMAX
        #include <windows.h>
        #undef WIN32_LEAN_AND_MEAN
        #undef NOMINMAX

        #pragma intrinsic(_ReadWriteBarrier)

    #endif
#endif

#include "../util_namespace.cuh"


CUB_NS_PREFIX

namespace cub {


struct Mutex
{
#if (__cplusplus > 199711L) || (defined(_MSC_VER) && _MSC_VER >= 1800)

    std::mutex mtx;

    void Lock()
    {
        mtx.lock();
    }

    void Unlock()
    {
        mtx.unlock();
    }

    void TryLock()
    {
        mtx.try_lock();
    }

#else       //__cplusplus > 199711L

    #if defined(_MSC_VER)

        // Microsoft VC++
        typedef long Spinlock;

    #else

        // GNU g++
        typedef int Spinlock;

        __forceinline__ void _ReadWriteBarrier()
        {
            __sync_synchronize();
        }

        __forceinline__ long _InterlockedExchange(volatile int * const Target, const int Value)
        {
            // NOTE: __sync_lock_test_and_set would be an acquire barrier, so we force a full barrier
            _ReadWriteBarrier();
            return __sync_lock_test_and_set(Target, Value);
        }

        __forceinline__ void YieldProcessor()
        {
        }

    #endif  // defined(_MSC_VER)

        volatile Spinlock lock;

        Mutex() : lock(0) {}

        __forceinline__ void Lock()
        {
            while (1)
            {
                if (!_InterlockedExchange(&lock, 1)) return;
                while (lock) YieldProcessor();
            }
        }


        __forceinline__ void Unlock()
        {
            _ReadWriteBarrier();
            lock = 0;
        }

#endif      // __cplusplus > 199711L

};




}               // CUB namespace
CUB_NS_POSTFIX  // Optional outer namespace(s)