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 #include "test/drifting_clock.h" 12 13 #include "rtc_base/checks.h" 14 15 namespace webrtc { 16 namespace test { 17 constexpr float DriftingClock::kNoDrift; 18 DriftingClock(Clock * clock,float speed)19DriftingClock::DriftingClock(Clock* clock, float speed) 20 : clock_(clock), drift_(speed - 1.0f), start_time_(clock_->CurrentTime()) { 21 RTC_CHECK(clock); 22 RTC_CHECK_GT(speed, 0.0f); 23 } 24 Drift() const25TimeDelta DriftingClock::Drift() const { 26 auto now = clock_->CurrentTime(); 27 RTC_DCHECK_GE(now, start_time_); 28 return (now - start_time_) * drift_; 29 } 30 Drift(Timestamp timestamp) const31Timestamp DriftingClock::Drift(Timestamp timestamp) const { 32 return timestamp + Drift() / 1000.; 33 } 34 Drift(NtpTime ntp_time) const35NtpTime DriftingClock::Drift(NtpTime ntp_time) const { 36 // NTP precision is 1/2^32 seconds, i.e. 2^32 ntp fractions = 1 second. 37 const double kNtpFracPerMicroSecond = 4294.967296; // = 2^32 / 10^6 38 39 uint64_t total_fractions = static_cast<uint64_t>(ntp_time); 40 total_fractions += Drift().us() * kNtpFracPerMicroSecond; 41 return NtpTime(total_fractions); 42 } 43 44 } // namespace test 45 } // namespace webrtc 46