信号量的实现

class OSCond
{
public:

   OSCond();
   ~OSCond();

   inline void     Signal();
   inline void     Wait(OSMutex* inMutex, SInt32 inTimeoutInMilSecs = 0);
   inline void     Broadcast();

private:

#ifdef __Win32__
   HANDLE              fCondition;
   UInt32              fWaitCount;
#elif __PTHREADS_MUTEXES__
   pthread_cond_t      fCondition;
   void                TimedWait(OSMutex* inMutex, SInt32 inTimeoutInMilSecs);
#else
   mycondition_t       fCondition;
#endif
};

inline void OSCond::Wait(OSMutex* inMutex, SInt32 inTimeoutInMilSecs)
{
#ifdef __Win32__
   DWORD theTimeout = INFINITE;
   if (inTimeoutInMilSecs > 0)
       theTimeout = inTimeoutInMilSecs;
   inMutex->Unlock();
   fWaitCount++;
   DWORD theErr = ::WaitForSingleObject(fCondition, theTimeout);
   fWaitCount--;
   Assert((theErr == WAIT_OBJECT_0) || (theErr == WAIT_TIMEOUT));
   inMutex->Lock();
#elif __PTHREADS_MUTEXES__
   this->TimedWait(inMutex, inTimeoutInMilSecs);
#else
   Assert(fCondition != NULL);
   mycondition_wait(fCondition, inMutex->fMutex, inTimeoutInMilSecs);
#endif
}

inline void OSCond::Signal()
{
#ifdef __Win32__
   BOOL theErr = ::SetEvent(fCondition);
   Assert(theErr == TRUE);
#elif __PTHREADS_MUTEXES__
   pthread_cond_signal(&fCondition);
#else
   Assert(fCondition != NULL);
   mycondition_signal(fCondition);
#endif
}

inline void OSCond::Broadcast()
{
#ifdef __Win32__
   //
   // There doesn't seem like any more elegant way to
   // implement Broadcast using events in Win32.
   // This will work, it may generate spurious wakeups,
   // but condition variables are allowed to generate
   // spurious wakeups
   UInt32 waitCount = fWaitCount;
   for (UInt32 x = 0; x < waitCount; x++)
   {
       BOOL theErr = ::SetEvent(fCondition);
       Assert(theErr == TRUE);
   }
#elif __PTHREADS_MUTEXES__
   pthread_cond_broadcast(&fCondition);
#else
   Assert(fCondition != NULL);
   mycondition_broadcast(fCondition);
#endif
}

#endif //_OSCOND_H_