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#ifndef SQUID_FADING_COUNTER_H
#define SQUID_FADING_COUNTER_H
#include "base/Vector.h"
/// Counts events, forgetting old ones. Usefull for "3 errors/minute" limits.
class FadingCounter
{
public:
FadingCounter();
/// 0=remember nothing; -1=forget nothing; new value triggers clear()
void configure(double horizonSeconds);
void clear(); ///< forgets all events
int count(int howMany); ///< count fresh, return #events remembered
int remembered() const { return total; } ///< possibly stale #events
/// read-only memory horizon in seconds; older events are forgotten
double horizon;
private:
const int precision; ///< #counting slots, controls measur. occuracy
double delta; ///< sub-interval duration = horizon/precision
double lastTime; ///< time of the last update
Vector<int> counters; ///< events per delta (possibly stale)
int total; ///< number of remembered events (possibly stale)
};
#endif /* SQUID_FADING_COUNTER_H */
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