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CAVERNts_condition_c.hxx

/******************************************************************
 * CAVERNsoft
 * Copyright (C) 1994-2000 Electronic Visualization Laboratory,
 * all rights reserved
 * By Jason Leigh, Yong-joo Cho, Naveen Krishnaprasad, Chris Scharver,
 * Stuart Bailey, Atul Nayak,Shalini Venkataraman
 * University of Illinois at Chicago
 * 
 * This publication and its text and code may not be copied for commercial 
 * use without the express written permission of the University of Illinois
 * at Chicago.
 * The contributors disclaim any representation of warranty: use this
 * code at your own risk.
 * Direct questions, comments etc to cavern@evl.uic.edu
 ******************************************************************/

#ifndef _CAVERNPLUS_CONDITION_C
#define _CAVERNPLUS_CONDITION_C

#include "CAVERNts_mutex_c.hxx"

#ifdef CAVERN_USE_GLOBUS_THREADS       
        typedef globus_cond_t CAVERN_COND_T;
#elif defined(CAVERN_USE_PTHREADS)
        typedef pthread_cond_t CAVERN_COND_T;
#elif defined(CAVERN_USE_WINDOWSTHREADS)
    class _CAVERN_COND_T 
    {
    public:
        _CAVERN_COND_T() {
            waiters = 0;
            wasBroadcast = 0;
            sema = CreateSemaphore(NULL, 0, 0xFFFFFFFF, NULL);
            waitersDone = CreateEvent(NULL, FALSE, FALSE, NULL);
            waitersLock = CreateMutex(NULL, FALSE, NULL);
        }

        virtual ~_CAVERN_COND_T() {
            if (waitersDone) CloseHandle(waitersDone);
            if (waitersLock) CloseHandle(waitersLock);
            if (sema) CloseHandle(sema);
        }

        long waiters;  // Number of waiting threads.
        HANDLE waitersLock; // Serialize access to the waiters count.

        // Queue up threads waiting for the condition to become signaled.
        HANDLE sema; 

        // An auto reset event used by the broadcast/signal thread to wait
        // for the waiting thread(s) to wake up and get a chance at the
        // semaphore.
        HANDLE waitersDone;

        // Keeps track of whether we were broadcasting or just signaling.
        size_t wasBroadcast;
    };

    typedef _CAVERN_COND_T * CAVERN_COND_T;
#else
        #error One of CAVERN_USE_GLOBUS_THREADS, CAVERN_USE_PTHREADS, or CAVERN_USE_WINDOWSTHREADS must be defined.
#endif

class CAVERNts_condition_c {
public:

        int wait(CAVERNts_mutex_c *mutex);

        int signal();

        int broadcastSignal();

        CAVERN_COND_T *getCondition();

        CAVERNts_condition_c();
        ~CAVERNts_condition_c();

private:
        CAVERN_COND_T itsCV;
};


#endif

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