ConditionVariable.hpp

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/*==========================================================================
 * Copyright (c) 2004 University of Massachusetts.  All Rights Reserved.
 *
 * Use of the Lemur Toolkit for Language Modeling and Information Retrieval
 * is subject to the terms of the software license set forth in the LICENSE
 * file included with this software, and also available at
 * http://www.lemurproject.org/license.html
 *
 *==========================================================================
 */

//
// ConditionVariable
//
// 15 November 2004 -- tds
//
// Implementation based on code from the ACE library (Schmidt)
//

#ifndef INDRI_CONDITIONVARIABLE_HPP
#define INDRI_CONDITIONVARIABLE_HPP

#ifndef WIN32
#include <pthread.h>
#include <sys/time.h>
#include <errno.h>
#endif


#include "indri/indri-platform.h"
#include "Mutex.hpp"
namespace indri
{
  namespace thread
  {
    class ConditionVariable {
    private:
#ifdef WIN32
      HANDLE _event;
      int _waiters;
#else
      pthread_cond_t _condition;
#endif

    public:
      ConditionVariable() {
#ifdef WIN32
        _event = ::CreateEvent( NULL, FALSE, FALSE, NULL );
        _waiters = 0;
#else
        pthread_cond_init( &_condition, NULL );
#endif
      }

      ~ConditionVariable() {
#ifdef WIN32
        ::CloseHandle( _event );
#else
        pthread_cond_destroy( &_condition );
#endif
      }

      void wait( Mutex& mutex ) {
#ifdef WIN32
        HRESULT result = ::SignalObjectAndWait( mutex._mutex, _event, INFINITE, FALSE );
        assert( SUCCEEDED(result) );
        mutex.lock();
#else
        pthread_cond_wait( &_condition, &mutex._mutex );
#endif
      }

      bool wait( Mutex& mutex, UINT64 microseconds ) {
#ifdef WIN32
        HRESULT result = ::SignalObjectAndWait( mutex._mutex, _event, DWORD(microseconds/1000), FALSE );
        assert( SUCCEEDED(result) );
        mutex.lock();
        return result != WAIT_TIMEOUT;
#else
        struct timeval tv;
        gettimeofday( &tv, 0 );

        UINT64 seconds = tv.tv_sec;
        seconds *= 1000 * 1000;
        microseconds += seconds; 
        microseconds += tv.tv_usec;

        struct timespec ts;
        ts.tv_sec = microseconds / 1000000;
        ts.tv_nsec = (microseconds % 1000000) * 1000;

        int result = pthread_cond_timedwait( &_condition, &mutex._mutex, &ts );
        return result != ETIMEDOUT;
#endif
      }


      void notifyOne( ) {
#ifdef WIN32
        ::SetEvent( _event );
#else
        pthread_cond_signal( &_condition );
#endif
      }

      void notifyAll( ) {
#ifdef WIN32
        ::SetEvent( _event );
#else
        pthread_cond_broadcast( &_condition );
#endif
      }
    };
  }
}

#endif // INDRI_CONDITIONVARIBLE_HPP

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