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61 lines
1.3 KiB
C++
61 lines
1.3 KiB
C++
//
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// Copyright (c) 2015 The ANGLE Project Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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//
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// OSXTimer.cpp: Implementation of a high precision timer class on OSX
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#include "osx/OSXTimer.h"
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#include <CoreServices/CoreServices.h>
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#include <mach/mach.h>
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#include <mach/mach_time.h>
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OSXTimer::OSXTimer()
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: mRunning(false)
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{
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}
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void OSXTimer::start()
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{
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mStartTime = mach_absolute_time();
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mRunning = true;
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}
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void OSXTimer::stop()
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{
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mStopTime = mach_absolute_time();
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mRunning = false;
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}
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double OSXTimer::getElapsedTime() const
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{
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// If this is the first time we've run, get the timebase.
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// We can use denom == 0 to indicate that sTimebaseInfo is
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// uninitialised because it makes no sense to have a zero
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// denominator in a fraction.
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static mach_timebase_info_data_t timebaseInfo;
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static double secondCoeff;
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if ( timebaseInfo.denom == 0 )
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{
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mach_timebase_info(&timebaseInfo);
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secondCoeff = timebaseInfo.numer * (1.0 / 1000000000) / timebaseInfo.denom;
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}
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if (mRunning)
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{
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return secondCoeff * (mach_absolute_time() - mStartTime);
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}
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else
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{
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return secondCoeff * (mStopTime - mStartTime);
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}
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}
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Timer *CreateTimer()
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{
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return new OSXTimer();
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}
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