timer.h

Go to the documentation of this file.

/*
 * timer.h
 *
 * 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.
 *
 *
 * Simple library for managing a timer queue.
 */

#ifndef WAVEPACKET_TIMER_H__
#define WAVEPACKET_TIMER_H__


// includes --------------------------------------------------------------------
#include "common/common.h"

#include "geometry/geometry_3d.h"
#include "threadsafe/smart_ptr.h"


namespace timer {

// doxygen block

/// \ingroup general
/*@{*/

////////////////////////////////////////////////////////////////////////////////
///
/// \defgroup timer Simple Timer Queue
///
///\n
/// A library for managing timers.  
///
/// General usage:
///     - create a queue object
///     - repeatedly call it on checkTimers()
///     - add timers with the timer::Queue::addTimer() method
///     - as timers expire in checkTimers(), their notifyTimer() method
///             will be called.
///
/// Time is specified using qword_t types (64 bit unsigned integers).  This is
/// the number of microseconds since the Epoch (Jan 1 1970).  Theoretically this
/// gives you microsecond-level timing for the next 584 thousand years.  In
/// practice, I doubt the kernel scheduler will do much better than millisecond
/// resolution.
///
/// The Queue object is threadsafe.  Thread safety of individual Timer objects
/// is up to the implementer.
///
////////////////////////////////////////////////////////////////////////////////
/*@{*/


/// base class from which you can inherit and construct your own timers
class Timer {
public:
        // virtual destructor --------------------------------------------------
        virtual ~Timer(void) throw();

        // timer::Timer class interface methods --------------------------------

        /// this method is called when the timer goes off
        virtual void notifyTimer(void) = 0;
};



/// this is a queue to which Timer objects can be added
class Queue {
public:
        // virtual destructor --------------------------------------------------
        virtual ~Queue(void) throw();

        // timer::Queue class interface methods --------------------------------

        /// add a timer which will go off in usFromNow microseconds
        virtual void addTimer(IN qword_t usFromNow,
                                IN smart_ptr<Timer>& timer) = 0;

        /// update the current time of the Queue object
        virtual void setTime(IN qword_t usSinceEpoch) throw() = 0;

        /// check all timers, given the current time.  Internally, this also
        ///  calls setTime().  So if you call checkTimers() often you may
        ///  never need to call setTime() explicitly.
        virtual void checkTimers(IN qword_t usSinceEpoch) = 0;


        // static factory methods ----------------------------------------------
        static smart_ptr<Queue> create(void);
};



};      // timer namespace

/*@}*/  // end of documentation block

#endif  // WAVEPACKET_TIMER_H__