condition.h

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 *
 * Condition.hpp
 * by Mark Gates <[e-mail]>
 * -------------------------------------------------------------------
 * An abstract class for waiting on a condition variable. If
 * threads are not available, this does nothing.
 * ------------------------------------------------------------------- */

#ifndef CONDITION_H
#define CONDITION_H

#include "headers.h"

#include "Mutex.hpp"

#include "util.h"

/* ------------------------------------------------------------------- */
class Condition : public Mutex
{
  public:
    // initialize condition
    Condition( void )
      : Mutex()
    {
      pthread_cond_init( &mCondition, NULL );
    }

    // make sure condition is unlocked TODO
    ~Condition()
    {
      pthread_cond_destroy( &mCondition );
    }

    // sleep this thread, waiting for condition signal
    void Wait( void )
    {
      pthread_cond_wait( &mCondition, &mMutex );
    }

    // sleep this thread, waiting for condition signal,
    // but bound sleep time by the relative time inSeconds.
    void TimedWait( time_t inSeconds )
    {
      struct timespec absTimeout;
      absTimeout.tv_sec  = time( NULL ) + inSeconds;
      absTimeout.tv_nsec = 0;

      pthread_cond_timedwait( &mCondition, &mMutex, &absTimeout );
    }

    // send a condition signal to wake one thread waiting on condition
    // in Win32, this actually wakes up all threads, same as Broadcast
    // use PulseEvent to auto-reset the signal after waking all threads
    void Signal( void )
    {
      pthread_cond_signal( &mCondition );
    }

    // send a condition signal to wake all threads waiting on condition
    void Broadcast( void )
    {
      pthread_cond_broadcast( &mCondition );
    }

  protected:
    pthread_cond_t mCondition;

}; // end class Condition

#endif // CONDITION_H