1 /* 2 * Copyright (c) 2016 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11 #ifndef RTC_BASE_RATE_LIMITER_H_ 12 #define RTC_BASE_RATE_LIMITER_H_ 13 14 #include <stddef.h> 15 #include <stdint.h> 16 17 #include "rtc_base/constructor_magic.h" 18 #include "rtc_base/rate_statistics.h" 19 #include "rtc_base/synchronization/mutex.h" 20 #include "rtc_base/thread_annotations.h" 21 22 namespace webrtc { 23 24 class Clock; 25 26 // Class used to limit a bitrate, making sure the average does not exceed a 27 // maximum as measured over a sliding window. This class is thread safe; all 28 // methods will acquire (the same) lock befeore executing. 29 class RateLimiter { 30 public: 31 RateLimiter(Clock* clock, int64_t max_window_ms); 32 ~RateLimiter(); 33 34 // Try to use rate to send bytes. Returns true on success and if so updates 35 // current rate. 36 bool TryUseRate(size_t packet_size_bytes); 37 38 // Set the maximum bitrate, in bps, that this limiter allows to send. 39 void SetMaxRate(uint32_t max_rate_bps); 40 41 // Set the window size over which to measure the current bitrate. 42 // For example, irt retransmissions, this is typically the RTT. 43 // Returns true on success and false if window_size_ms is out of range. 44 bool SetWindowSize(int64_t window_size_ms); 45 46 private: 47 Clock* const clock_; 48 Mutex lock_; 49 RateStatistics current_rate_ RTC_GUARDED_BY(lock_); 50 int64_t window_size_ms_ RTC_GUARDED_BY(lock_); 51 uint32_t max_rate_bps_ RTC_GUARDED_BY(lock_); 52 53 RTC_DISALLOW_IMPLICIT_CONSTRUCTORS(RateLimiter); 54 }; 55 56 } // namespace webrtc 57 58 #endif // RTC_BASE_RATE_LIMITER_H_ 59