1 /* 2 * libjingle 3 * Copyright 2004--2010, Google Inc. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright notice, 9 * this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright notice, 11 * this list of conditions and the following disclaimer in the documentation 12 * and/or other materials provided with the distribution. 13 * 3. The name of the author may not be used to endorse or promote products 14 * derived from this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 17 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 18 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO 19 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #include "talk/base/ratetracker.h" 29 #include "talk/base/time.h" 30 31 namespace talk_base { 32 33 RateTracker::RateTracker() 34 : total_units_(0), units_second_(0), 35 last_units_second_time_(static_cast<uint32>(-1)), 36 last_units_second_calc_(0) { 37 } 38 39 size_t RateTracker::total_units() const { 40 return total_units_; 41 } 42 43 size_t RateTracker::units_second() { 44 // Snapshot units / second calculator. Determine how many seconds have 45 // elapsed since our last reference point. If over 1 second, establish 46 // a new reference point that is an integer number of seconds since the 47 // last one, and compute the units over that interval. 48 uint32 current_time = Time(); 49 if (last_units_second_time_ != static_cast<uint32>(-1)) { 50 int delta = talk_base::TimeDiff(current_time, last_units_second_time_); 51 if (delta >= 1000) { 52 int fraction_time = delta % 1000; 53 int seconds = delta / 1000; 54 int fraction_units = 55 static_cast<int>(total_units_ - last_units_second_calc_) * 56 fraction_time / delta; 57 // Compute "units received during the interval" / "seconds in interval" 58 units_second_ = 59 (total_units_ - last_units_second_calc_ - fraction_units) / seconds; 60 last_units_second_time_ = current_time - fraction_time; 61 last_units_second_calc_ = total_units_ - fraction_units; 62 } 63 } 64 if (last_units_second_time_ == static_cast<uint32>(-1)) { 65 last_units_second_time_ = current_time; 66 last_units_second_calc_ = total_units_; 67 } 68 69 return units_second_; 70 } 71 72 void RateTracker::Update(size_t units) { 73 total_units_ += units; 74 } 75 76 uint32 RateTracker::Time() const { 77 return talk_base::Time(); 78 } 79 80 } // namespace talk_base 81
