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/* Copyright (C) 2006 Constantin Kaplinsky. All Rights Reserved.
*
* This is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this software; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
* USA.
*/
//
// PollingScheduler class. It is used for deciding when to start new
// polling pass, and how much time it is ok to sleep before starting.
// PollingScheduler is given a desired polling interval, but it can
// add time between polling passes if needed for satisfying processor
// usage limitation.
//
#ifndef __POLLINGSCHEDULER_H__
#define __POLLINGSCHEDULER_H__
#include <x0vncserver/TimeMillis.h>
class PollingScheduler {
public:
PollingScheduler(int interval, int maxload = 50);
// Set polling parameters.
void setParameters(int interval, int maxload = 50);
// Reset the object into the initial state (no polling performed).
void reset();
// Check if the object is active (not in the initial state).
bool isRunning();
// Tell the scheduler that new polling pass is just being started.
void newPass();
// Inform the scheduler about times when we sleep.
void sleepStarted();
void sleepFinished();
// This function estimates time remaining before new polling pass.
int millisRemaining() const;
// This function tells if it's ok to start polling pass right now.
bool goodTimeToPoll() const;
protected:
// Parameters.
int m_interval;
int m_maxload;
// This boolean flag is true when we do not poll the screen.
bool m_initialState;
// Time stamp saved on starting current polling pass.
TimeMillis m_passStarted;
// Desired duration of current polling pass.
int m_ratedDuration;
// These are for measuring sleep time in current pass.
TimeMillis m_sleepStarted;
bool m_sleeping;
int m_sleptThisPass;
// Ring buffer for tracking past timing errors.
int m_errors[8];
int m_errorSum;
int m_errorAbsSum;
// Ring buffer for tracking total pass durations (work + sleep).
int m_durations[8];
int m_durationSum;
// Ring buffer for tracking past sleep times.
int m_slept[8];
int m_sleptSum;
// Indexer for all ring buffers.
int m_idx;
// Pass counter.
int m_count;
};
#endif // __POLLINGSCHEDULER_H__
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