100 lines
4.4 KiB
C++
100 lines
4.4 KiB
C++
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/*
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File: CAHostTimeBase.cpp
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Abstract: CAHostTimeBase.h
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Version: 1.1
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Disclaimer: IMPORTANT: This Apple software is supplied to you by Apple
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Inc. ("Apple") in consideration of your agreement to the following
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terms, and your use, installation, modification or redistribution of
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this Apple software constitutes acceptance of these terms. If you do
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not agree with these terms, please do not use, install, modify or
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redistribute this Apple software.
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In consideration of your agreement to abide by the following terms, and
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subject to these terms, Apple grants you a personal, non-exclusive
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license, under Apple's copyrights in this original Apple software (the
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"Apple Software"), to use, reproduce, modify and redistribute the Apple
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Software, with or without modifications, in source and/or binary forms;
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provided that if you redistribute the Apple Software in its entirety and
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without modifications, you must retain this notice and the following
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text and disclaimers in all such redistributions of the Apple Software.
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Neither the name, trademarks, service marks or logos of Apple Inc. may
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be used to endorse or promote products derived from the Apple Software
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without specific prior written permission from Apple. Except as
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expressly stated in this notice, no other rights or licenses, express or
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implied, are granted by Apple herein, including but not limited to any
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patent rights that may be infringed by your derivative works or by other
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works in which the Apple Software may be incorporated.
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The Apple Software is provided by Apple on an "AS IS" basis. APPLE
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MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION
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THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS
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FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND
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OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS.
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IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL
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OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION,
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MODIFICATION AND/OR DISTRIBUTION OF THE APPLE SOFTWARE, HOWEVER CAUSED
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AND WHETHER UNDER THEORY OF CONTRACT, TORT (INCLUDING NEGLIGENCE),
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STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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Copyright (C) 2014 Apple Inc. All Rights Reserved.
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*/
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//=============================================================================
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// Includes
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//=============================================================================
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#include "CAHostTimeBase.h"
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Float64 CAHostTimeBase::sFrequency = 0;
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Float64 CAHostTimeBase::sInverseFrequency = 0;
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UInt32 CAHostTimeBase::sMinDelta = 0;
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UInt32 CAHostTimeBase::sToNanosNumerator = 0;
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UInt32 CAHostTimeBase::sToNanosDenominator = 0;
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pthread_once_t CAHostTimeBase::sIsInited = PTHREAD_ONCE_INIT;
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#if Track_Host_TimeBase
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UInt64 CAHostTimeBase::sLastTime = 0;
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#endif
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//=============================================================================
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// CAHostTimeBase
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//
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// This class provides platform independent access to the host's time base.
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//=============================================================================
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void CAHostTimeBase::Initialize()
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{
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// get the info about Absolute time
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#if TARGET_OS_MAC
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struct mach_timebase_info theTimeBaseInfo;
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mach_timebase_info(&theTimeBaseInfo);
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sMinDelta = 1;
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sToNanosNumerator = theTimeBaseInfo.numer;
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sToNanosDenominator = theTimeBaseInfo.denom;
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// the frequency of that clock is: (sToNanosDenominator / sToNanosNumerator) * 10^9
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sFrequency = static_cast<Float64>(sToNanosDenominator) / static_cast<Float64>(sToNanosNumerator);
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sFrequency *= 1000000000.0;
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#elif TARGET_OS_WIN32
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LARGE_INTEGER theFrequency;
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QueryPerformanceFrequency(&theFrequency);
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sMinDelta = 1;
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sToNanosNumerator = 1000000000ULL;
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sToNanosDenominator = *((UInt64*)&theFrequency);
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sFrequency = static_cast<Float64>(*((UInt64*)&theFrequency));
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#endif
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sInverseFrequency = 1.0 / sFrequency;
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#if Log_Host_Time_Base_Parameters
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DebugPrintf("Host Time Base Parameters");
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DebugPrintf(" Minimum Delta: %lu", (unsigned long)sMinDelta);
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DebugPrintf(" Frequency: %f", sFrequency);
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DebugPrintf(" To Nanos Numerator: %lu", (unsigned long)sToNanosNumerator);
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DebugPrintf(" To Nanos Denominator: %lu", (unsigned long)sToNanosDenominator);
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#endif
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}
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