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/rate_statistics.h" 18 #include "rtc_base/synchronization/mutex.h" 19 #include "rtc_base/thread_annotations.h" 20 21 namespace webrtc { 22 23 class Clock; 24 25 // Class used to limit a bitrate, making sure the average does not exceed a 26 // maximum as measured over a sliding window. This class is thread safe; all 27 // methods will acquire (the same) lock befeore executing. 28 class RateLimiter { 29 public: 30 RateLimiter(Clock* clock, int64_t max_window_ms); 31 32 RateLimiter() = delete; 33 RateLimiter(const RateLimiter&) = delete; 34 RateLimiter& operator=(const RateLimiter&) = delete; 35 36 ~RateLimiter(); 37 38 // Try to use rate to send bytes. Returns true on success and if so updates 39 // current rate. 40 bool TryUseRate(size_t packet_size_bytes); 41 42 // Set the maximum bitrate, in bps, that this limiter allows to send. 43 void SetMaxRate(uint32_t max_rate_bps); 44 45 // Set the window size over which to measure the current bitrate. 46 // For example, irt retransmissions, this is typically the RTT. 47 // Returns true on success and false if window_size_ms is out of range. 48 bool SetWindowSize(int64_t window_size_ms); 49 50 private: 51 Clock* const clock_; 52 Mutex lock_; 53 RateStatistics current_rate_ RTC_GUARDED_BY(lock_); 54 int64_t window_size_ms_ RTC_GUARDED_BY(lock_); 55 uint32_t max_rate_bps_ RTC_GUARDED_BY(lock_); 56 }; 57 58 } // namespace webrtc 59 60 #endif // RTC_BASE_RATE_LIMITER_H_ 61