henrike@webrtc.org | f7795df | 2014-05-13 18:00:26 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 2004 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 | #include "webrtc/base/ratetracker.h" |
| 12 | #include "webrtc/base/timeutils.h" |
| 13 | |
| 14 | namespace rtc { |
| 15 | |
| 16 | RateTracker::RateTracker() |
| 17 | : total_units_(0), units_second_(0), |
| 18 | last_units_second_time_(static_cast<uint32>(-1)), |
| 19 | last_units_second_calc_(0) { |
| 20 | } |
| 21 | |
| 22 | size_t RateTracker::total_units() const { |
| 23 | return total_units_; |
| 24 | } |
| 25 | |
| 26 | size_t RateTracker::units_second() { |
| 27 | // Snapshot units / second calculator. Determine how many seconds have |
| 28 | // elapsed since our last reference point. If over 1 second, establish |
| 29 | // a new reference point that is an integer number of seconds since the |
| 30 | // last one, and compute the units over that interval. |
| 31 | uint32 current_time = Time(); |
| 32 | if (last_units_second_time_ != static_cast<uint32>(-1)) { |
| 33 | int delta = rtc::TimeDiff(current_time, last_units_second_time_); |
| 34 | if (delta >= 1000) { |
| 35 | int fraction_time = delta % 1000; |
| 36 | int seconds = delta / 1000; |
| 37 | int fraction_units = |
| 38 | static_cast<int>(total_units_ - last_units_second_calc_) * |
| 39 | fraction_time / delta; |
| 40 | // Compute "units received during the interval" / "seconds in interval" |
| 41 | units_second_ = |
| 42 | (total_units_ - last_units_second_calc_ - fraction_units) / seconds; |
| 43 | last_units_second_time_ = current_time - fraction_time; |
| 44 | last_units_second_calc_ = total_units_ - fraction_units; |
| 45 | } |
| 46 | } |
| 47 | if (last_units_second_time_ == static_cast<uint32>(-1)) { |
| 48 | last_units_second_time_ = current_time; |
| 49 | last_units_second_calc_ = total_units_; |
| 50 | } |
| 51 | |
| 52 | return units_second_; |
| 53 | } |
| 54 | |
| 55 | void RateTracker::Update(size_t units) { |
| 56 | total_units_ += units; |
| 57 | } |
| 58 | |
| 59 | uint32 RateTracker::Time() const { |
| 60 | return rtc::Time(); |
| 61 | } |
| 62 | |
| 63 | } // namespace rtc |