OpenSubdiv/examples/mutex/mutex.h

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#ifndef MUTEX_H
#define MUTEX_H


#if defined(_WINDOWS)

    #include <Windows.h>

    class Mutex {
    public:

        Mutex(int spincount=0) {
            if (spincount)
                InitializeCriticalSectionAndSpinCount(&_cs, spincount);
            else
                InitializeCriticalSection(&_cs);
        }

        void Lock() {
            EnterCriticalSection(&_cs);
        }

        bool Try() { 
            return TryEnterCriticalSection(&_cs)!=0; 
        }

        void Unlock() {
            LeaveCriticalSection(&_cs);
        }

    private:
        Mutex(Mutex const &); 
        Mutex & operator=(Mutex const &);

        CRITICAL_SECTION _cs;
    };

#elif defined(__APPLE__) or defined(__linux)

    #include <pthread.h>
    #include <assert.h>

    class Mutex {
    public:

        Mutex(int spincount=0) : _spincount(spincount) {
            assert( pthread_mutex_init(&_mutex,NULL) );
        }

        ~Mutex() {
            assert( pthread_mutex_destroy(&_mutex)==0 );
        }

        void Lock() {
            if (_spincount) {
                int spincount = _spincount;
                while (spincount--)
                    if (pthread_mutex_trylock(&_mutex) == 0) 
                        return;
                
            }
            assert( pthread_mutex_lock(&_mutex)==0 );
        }
        
        bool Try() {
            return (pthread_mutex_trylock(&_mutex) == 0);
        }

        void Unlock() {
            assert(pthread_mutex_unlock(&_mutex)==0);
        }

    private:
        Mutex(Mutex const &); 
        Mutex & operator=(Mutex const &);
        
        pthread_mutex_t _mutex;
        const int _spincount;
    };

#endif

#endif // MUTEX_H