chromium/media/base/feedback_signal_accumulator.h

// Copyright 2015 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef MEDIA_BASE_FEEDBACK_SIGNAL_ACCUMULATOR_H_
#define MEDIA_BASE_FEEDBACK_SIGNAL_ACCUMULATOR_H_

#include <algorithm>
#include <cmath>
#include <ostream>

#include "base/time/time.h"

namespace media {

// Utility class for maintaining an exponentially-decaying average of feedback
// signal values whose updates occur at undetermined, possibly irregular time
// intervals.
//
// Feedback signals can be made by multiple sources.  Meaning, there can be
// several values provided for the same timestamp.  In this case, the greatest
// value is retained and used to re-compute the average.  Therefore, the values
// provided to this class' methods should be appropriately translated with this
// in mind.  For example, an "fraction available" metric should be translated
// into a "fraction utilized" one.
//
// Usage note: Reset() must be called at least once before the first call to
// Update().
//
// This template class supports data points that are timestamped using either
// |base::TimeDelta| or |base::TimeTicks|.
template <typename TimeType>
class FeedbackSignalAccumulator { … };

}  // namespace media

#endif  // MEDIA_BASE_FEEDBACK_SIGNAL_ACCUMULATOR_H_