timer.cpp

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/*
 * timer.cpp
 *
 * Copyright (c) 2009 Thomas A. Vaughan
 * All rights reserved.
 *
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the <organization> nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THOMAS A. VAUGHAN ''AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THOMAS A. VAUGHAN BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Implementation of a simple timer queue.  See timer.h
 */

// includes --------------------------------------------------------------------
#include "timer.h"              // always include our own header first

#include <fstream>

#include "common/wave_ex.h"
#include "perf/perf.h"
#include "util/token_stream.h"


namespace timer {

/// \ingroup timer
/*@{*/


// interface destructors
Timer::~Timer(void) throw() { }
Queue::~Queue(void) throw() { }


////////////////////////////////////////////////////////////////////////////////
//
//      static helper methods
//
////////////////////////////////////////////////////////////////////////////////


////////////////////////////////////////////////////////////////////////////////
//
//      QImpl -- class that implements the timer::Queue interface
//
////////////////////////////////////////////////////////////////////////////////

class QImpl : public Queue {
public:
        // constructor, destructor ---------------------------------------------
        QImpl(void) throw();
        ~QImpl(void) throw() { }

        // public class methods ------------------------------------------------
        void initialize(void) throw() { }

        // timer::Queue class interface methods --------------------------------
        void addTimer(IN qword_t microseconds,
                                IN smart_ptr<Timer>& timer);
        void setTime(IN qword_t usSinceEpoch) throw();
        void checkTimers(IN qword_t usSinceEpoch);

private:
        // private typedefs ----------------------------------------------------
        typedef std::multimap<qword_t, smart_ptr<Timer> > timer_map_t;

        // private member data -------------------------------------------------
        smart_mutex             m_mutex;
        qword_t                 m_currentTime;
        timer_map_t             m_timerMap;
};



QImpl::QImpl(void)
throw()
{
        m_currentTime = 0;
}



void
QImpl::addTimer
(
IN qword_t microseconds,
IN smart_ptr<Timer>& timer
)
{
        ASSERT(timer, "null");
        qword_t alarmTime = m_currentTime + microseconds;

        // lock!
        mlock m(m_mutex);
        m_timerMap.insert(timer_map_t::value_type(alarmTime, timer));
}



void
QImpl::setTime
(
IN qword_t usSinceEpoch
)
throw()
{
        m_currentTime = usSinceEpoch;
}



void
QImpl::checkTimers
(
IN qword_t usSinceEpoch
)
{
        // update time (can do this outside mutex)
        this->setTime(usSinceEpoch);

        // lock!
        mlock m(m_mutex);

        // iterate over all timers up to current time
        while (true) {
                timer_map_t::iterator i = m_timerMap.begin();
                if (m_timerMap.end() == i)
                        return;         // end of map!

                qword_t qTime = i->first;
                if (qTime > usSinceEpoch)
                        return; // remaining timers are later

                // timer is up!  notify
                Timer * timer = i->second;
                ASSERT(timer, "null");
                timer->notifyTimer();

                // remove timer from queue
                m_timerMap.erase(i);
        }
}



////////////////////////////////////////////////////////////////////////////////
//
//      Public APIs
//
////////////////////////////////////////////////////////////////////////////////

smart_ptr<Queue>
Queue::create
(
void
)
{
        smart_ptr<QImpl> local = new QImpl;
        ASSERT(local, "out of memory");

        local->initialize();

        return local;
}



};      // timer namespace