d28db7fd65
Depends on Chrome cl https://codereview.chromium.org/1888003002/, which was landed some time ago. BUG=webrtc:5740 R=stefan@webrtc.org, tommi@webrtc.org Review URL: https://codereview.webrtc.org/1888593004 . Cr-Commit-Position: refs/heads/master@{#12674}
103 lines
3.2 KiB
C++
103 lines
3.2 KiB
C++
/*
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* Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "webrtc/base/timeutils.h"
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#include "webrtc/modules/audio_conference_mixer/source/time_scheduler.h"
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#include "webrtc/system_wrappers/include/critical_section_wrapper.h"
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namespace webrtc {
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TimeScheduler::TimeScheduler(const int64_t periodicityInMs)
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: _crit(CriticalSectionWrapper::CreateCriticalSection()),
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_isStarted(false),
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_lastPeriodMark(),
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_periodicityInMs(periodicityInMs),
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_periodicityInTicks(periodicityInMs * rtc::kNumNanosecsPerMillisec),
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_missedPeriods(0)
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{
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}
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TimeScheduler::~TimeScheduler()
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{
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delete _crit;
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}
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int32_t TimeScheduler::UpdateScheduler()
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{
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CriticalSectionScoped cs(_crit);
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if(!_isStarted)
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{
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_isStarted = true;
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_lastPeriodMark = rtc::TimeNanos();
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return 0;
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}
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// Don't perform any calculations until the debt of pending periods have
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// been worked off.
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if(_missedPeriods > 0)
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{
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_missedPeriods--;
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return 0;
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}
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// Calculate the time that has past since previous call to this function.
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int64_t tickNow = rtc::TimeNanos();
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int64_t amassedTicks = tickNow - _lastPeriodMark;
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int64_t amassedMs = amassedTicks / rtc::kNumNanosecsPerMillisec;
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// Calculate the number of periods the time that has passed correspond to.
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int64_t periodsToClaim = amassedMs / _periodicityInMs;
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// One period will be worked off by this call. Make sure that the number of
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// pending periods don't end up being negative (e.g. if this function is
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// called to often).
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if(periodsToClaim < 1)
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{
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periodsToClaim = 1;
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}
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// Update the last period mark without introducing any drifting.
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// Note that if this fuunction is called to often _lastPeriodMark can
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// refer to a time in the future which in turn will yield TimeToNextUpdate
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// that is greater than the periodicity
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for(int64_t i = 0; i < periodsToClaim; i++)
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{
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_lastPeriodMark += _periodicityInTicks;
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}
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// Update the total amount of missed periods note that we have processed
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// one period hence the - 1
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_missedPeriods += periodsToClaim - 1;
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return 0;
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}
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int32_t TimeScheduler::TimeToNextUpdate(
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int64_t& updateTimeInMS) const
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{
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CriticalSectionScoped cs(_crit);
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// Missed periods means that the next UpdateScheduler() should happen
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// immediately.
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if(_missedPeriods > 0)
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{
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updateTimeInMS = 0;
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return 0;
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}
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// Calculate the time (in ms) that has past since last call to
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// UpdateScheduler()
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int64_t tickNow = rtc::TimeNanos();
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int64_t ticksSinceLastUpdate = tickNow - _lastPeriodMark;
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const int64_t millisecondsSinceLastUpdate =
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ticksSinceLastUpdate / rtc::kNumNanosecsPerMillisec;
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updateTimeInMS = _periodicityInMs - millisecondsSinceLastUpdate;
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updateTimeInMS = (updateTimeInMS < 0) ? 0 : updateTimeInMS;
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return 0;
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}
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} // namespace webrtc
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