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/*
* Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "system_wrappers/include/clock.h"
#include "rtc_base/time_utils.h"
namespace webrtc {
namespace {
int64_t NtpOffsetUsCalledOnce() {
constexpr int64_t kNtpJan1970Sec = 2208988800;
int64_t clock_time = rtc::TimeMicros();
int64_t utc_time = rtc::TimeUTCMicros();
return utc_time - clock_time + kNtpJan1970Sec * rtc::kNumMicrosecsPerSec;
}
NtpTime TimeMicrosToNtp(int64_t time_us) {
static int64_t ntp_offset_us = NtpOffsetUsCalledOnce();
int64_t time_ntp_us = time_us + ntp_offset_us;
RTC_DCHECK_GE(time_ntp_us, 0); // Time before year 1900 is unsupported.
// Convert seconds to uint32 through uint64 for a well-defined cast.
// A wrap around, which will happen in 2036, is expected for NTP time.
uint32_t ntp_seconds =
static_cast<uint64_t>(time_ntp_us / rtc::kNumMicrosecsPerSec);
// Scale fractions of the second to NTP resolution.
constexpr int64_t kNtpFractionsInSecond = 1LL << 32;
int64_t us_fractions = time_ntp_us % rtc::kNumMicrosecsPerSec;
uint32_t ntp_fractions =
us_fractions * kNtpFractionsInSecond / rtc::kNumMicrosecsPerSec;
return NtpTime(ntp_seconds, ntp_fractions);
}
} // namespace
class RealTimeClock : public Clock {
public:
RealTimeClock() = default;
Timestamp CurrentTime() override {
return Timestamp::Micros(rtc::TimeMicros());
}
NtpTime ConvertTimestampToNtpTime(Timestamp timestamp) override {
return TimeMicrosToNtp(timestamp.us());
}
};
Clock* Clock::GetRealTimeClockRaw() {
static Clock* const clock = new RealTimeClock();
return clock;
}
SimulatedClock::SimulatedClock(int64_t initial_time_us)
: time_us_(initial_time_us) {}
SimulatedClock::SimulatedClock(Timestamp initial_time)
: SimulatedClock(initial_time.us()) {}
SimulatedClock::~SimulatedClock() {}
Timestamp SimulatedClock::CurrentTime() {
return Timestamp::Micros(time_us_.load(std::memory_order_relaxed));
}
NtpTime SimulatedClock::ConvertTimestampToNtpTime(Timestamp timestamp) {
int64_t now_us = timestamp.us();
uint32_t seconds = (now_us / 1'000'000) + kNtpJan1970;
uint32_t fractions = static_cast<uint32_t>(
(now_us % 1'000'000) * kMagicNtpFractionalUnit / 1'000'000);
return NtpTime(seconds, fractions);
}
void SimulatedClock::AdvanceTimeMilliseconds(int64_t milliseconds) {
AdvanceTime(TimeDelta::Millis(milliseconds));
}
void SimulatedClock::AdvanceTimeMicroseconds(int64_t microseconds) {
AdvanceTime(TimeDelta::Micros(microseconds));
}
// TODO(bugs.webrtc.org(12102): It's desirable to let a single thread own
// advancement of the clock. We could then replace this read-modify-write
// operation with just a thread checker. But currently, that breaks a couple of
// tests, in particular, RepeatingTaskTest.ClockIntegration and
// CallStatsTest.LastProcessedRtt.
void SimulatedClock::AdvanceTime(TimeDelta delta) {
time_us_.fetch_add(delta.us(), std::memory_order_relaxed);
}
} // namespace webrtc
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