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/*
* Copyright 2012 The WebRTC Project Authors. All rights reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#ifndef RTC_BASE_DATA_RATE_LIMITER_H_
#define RTC_BASE_DATA_RATE_LIMITER_H_
#include <stddef.h>
#include "rtc_base/system/rtc_export.h"
namespace rtc {
// Limits the rate of use to a certain maximum quantity per period of
// time. Use, for example, for simple bandwidth throttling.
//
// It's implemented like a diet plan: You have so many calories per
// day. If you hit the limit, you can't eat any more until the next
// day.
class RTC_EXPORT DataRateLimiter {
public:
// For example, 100kb per second.
DataRateLimiter(size_t max, double period)
: max_per_period_(max),
period_length_(period),
used_in_period_(0),
period_start_(0.0),
period_end_(period) {}
virtual ~DataRateLimiter() {}
// Returns true if if the desired quantity is available in the
// current period (< (max - used)). Once the given time passes the
// end of the period, used is set to zero and more use is available.
bool CanUse(size_t desired, double time);
// Increment the quantity used this period. If past the end of a
// period, a new period is started.
void Use(size_t used, double time);
size_t used_in_period() const { return used_in_period_; }
size_t max_per_period() const { return max_per_period_; }
private:
size_t max_per_period_;
double period_length_;
size_t used_in_period_;
double period_start_;
double period_end_;
};
} // namespace rtc
#endif // RTC_BASE_DATA_RATE_LIMITER_H_
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