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//-----------------------------------------------------------------------------
/** @file libboardgame_base/IntervalChecker.h
@author Markus Enzenberger
@copyright GNU General Public License version 3 or later */
//-----------------------------------------------------------------------------
#ifndef LIBBOARDGAME_BASE_INTERVAL_CHECKER_H
#define LIBBOARDGAME_BASE_INTERVAL_CHECKER_H
#include <functional>
#include "TimeSource.h"
namespace libboardgame_base {
using namespace std;
//-----------------------------------------------------------------------------
/** Reduces regular calls to an expensive function to a given time interval.
The class assumes that its check() function is called in regular time
intervals and forwards only every n'th call to the expensive function with
n being adjusted dynamically to a given time interval. check() returns
true, if the expensive function was called and returned true in the
past. */
class IntervalChecker
{
public:
/** Constructor.
@param time_source The time source. The lifetime of this
parameter must exceed the lifetime of the class instance.
@param time_interval The time interval in seconds
@param f The expensive function */
IntervalChecker(TimeSource& time_source, double time_interval,
const function<bool()>& f);
bool operator()();
/** Disable the dynamic updating of the interval.
Can be used if the non-reproducability of the time measurement used
for dynamic updating of the check interval is undesirable.
@param interval The fixed interval (number of calls) to use for calling
the expensive function. (Must be greater zero). */
void set_deterministic(unsigned interval);
protected:
TimeSource& m_time_source;
private:
bool m_is_first_check = true;
bool m_is_deterministic = false;
bool m_result = false;
unsigned m_count = 1;
unsigned m_count_interval = 1;
double m_time_interval;
double m_last_time;
function<bool()> m_function;
bool check_expensive();
};
inline bool IntervalChecker::operator()()
{
if (--m_count == 0)
return check_expensive();
return m_result;
}
//-----------------------------------------------------------------------------
} // namespace libboardgame_base
#endif // LIBBOARDGAME_BASE_INTERVAL_CHECKER_H
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