boo/lib/audiodev/CAHostTimeBase.h

/*
     File: CAHostTimeBase.h
 Abstract: Part of CoreAudio Utility Classes
  Version: 1.1

 Disclaimer: IMPORTANT:  This Apple software is supplied to you by Apple
 Inc. ("Apple") in consideration of your agreement to the following
 terms, and your use, installation, modification or redistribution of
 this Apple software constitutes acceptance of these terms.  If you do
 not agree with these terms, please do not use, install, modify or
 redistribute this Apple software.

 In consideration of your agreement to abide by the following terms, and
 subject to these terms, Apple grants you a personal, non-exclusive
 license, under Apple's copyrights in this original Apple software (the
 "Apple Software"), to use, reproduce, modify and redistribute the Apple
 Software, with or without modifications, in source and/or binary forms;
 provided that if you redistribute the Apple Software in its entirety and
 without modifications, you must retain this notice and the following
 text and disclaimers in all such redistributions of the Apple Software.
 Neither the name, trademarks, service marks or logos of Apple Inc. may
 be used to endorse or promote products derived from the Apple Software
 without specific prior written permission from Apple.  Except as
 expressly stated in this notice, no other rights or licenses, express or
 implied, are granted by Apple herein, including but not limited to any
 patent rights that may be infringed by your derivative works or by other
 works in which the Apple Software may be incorporated.

 The Apple Software is provided by Apple on an "AS IS" basis.  APPLE
 MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION
 THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS
 FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND
 OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS.

 IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL
 OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 INTERRUPTION) ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION,
 MODIFICATION AND/OR DISTRIBUTION OF THE APPLE SOFTWARE, HOWEVER CAUSED
 AND WHETHER UNDER THEORY OF CONTRACT, TORT (INCLUDING NEGLIGENCE),
 STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN ADVISED OF THE
 POSSIBILITY OF SUCH DAMAGE.

 Copyright (C) 2014 Apple Inc. All Rights Reserved.

*/
#if !defined(__CAHostTimeBase_h__)
#define __CAHostTimeBase_h__

//=============================================================================
//	Includes
//=============================================================================

#if !defined(__COREAUDIO_USE_FLAT_INCLUDES__)
	#include <CoreAudio/CoreAudioTypes.h>
#else
	#include <CoreAudioTypes.h>
#endif

#if TARGET_OS_MAC
	#include <mach/mach_time.h>
	#include <pthread.h>
#elif TARGET_OS_WIN32
	#include <windows.h>
	#include "WinPThreadDefs.h"
#else
	#error	Unsupported operating system
#endif

#include "CADebugPrintf.h"

//=============================================================================
//	CAHostTimeBase
//
//	This class provides platform independent access to the host's time base.
//=============================================================================

#if CoreAudio_Debug
//	#define Log_Host_Time_Base_Parameters	1
//	#define Track_Host_TimeBase				1
#endif

class	CAHostTimeBase
{

public:
	static UInt64			ConvertToNanos(UInt64 inHostTime);
	static UInt64			ConvertFromNanos(UInt64 inNanos);

	static UInt64			GetTheCurrentTime();
#if TARGET_OS_MAC
	static UInt64			GetCurrentTime() { return GetTheCurrentTime(); }
#endif
	static UInt64			GetCurrentTimeInNanos();

	static Float64			GetFrequency() { pthread_once(&sIsInited, Initialize); return sFrequency; }
	static Float64			GetInverseFrequency() { pthread_once(&sIsInited, Initialize); return sInverseFrequency; }
	static UInt32			GetMinimumDelta() { pthread_once(&sIsInited, Initialize); return sMinDelta; }

	static UInt64			AbsoluteHostDeltaToNanos(UInt64 inStartTime, UInt64 inEndTime);
	static SInt64			HostDeltaToNanos(UInt64 inStartTime, UInt64 inEndTime);

	static UInt64			MultiplyByRatio(UInt64 inMuliplicand, UInt32 inNumerator, UInt32 inDenominator);

private:
	static void				Initialize();

	static pthread_once_t	sIsInited;

	static Float64			sFrequency;
	static Float64			sInverseFrequency;
	static UInt32			sMinDelta;
	static UInt32			sToNanosNumerator;
	static UInt32			sToNanosDenominator;
#if Track_Host_TimeBase
	static UInt64			sLastTime;
#endif
};

inline UInt64	CAHostTimeBase::GetTheCurrentTime()
{
	UInt64 theTime = 0;

	#if TARGET_OS_MAC
		theTime = mach_absolute_time();
	#elif TARGET_OS_WIN32
		LARGE_INTEGER theValue;
		QueryPerformanceCounter(&theValue);
		theTime = *((UInt64*)&theValue);
	#endif

	#if	Track_Host_TimeBase
		if(sLastTime != 0)
		{
			if(theTime <= sLastTime)
			{
				DebugPrintf("CAHostTimeBase::GetTheCurrentTime: the current time is earlier than the last time, now: %qd, then: %qd", theTime, sLastTime);
			}
			sLastTime = theTime;
		}
		else
		{
			sLastTime = theTime;
		}
	#endif

	return theTime;
}

inline UInt64	CAHostTimeBase::ConvertToNanos(UInt64 inHostTime)
{
	pthread_once(&sIsInited, Initialize);

	UInt64 theAnswer = MultiplyByRatio(inHostTime, sToNanosNumerator, sToNanosDenominator);
	#if CoreAudio_Debug
		if(((sToNanosNumerator > sToNanosDenominator) && (theAnswer < inHostTime)) || ((sToNanosDenominator > sToNanosNumerator) && (theAnswer > inHostTime)))
		{
			DebugPrintf("CAHostTimeBase::ConvertToNanos: The conversion wrapped");
		}
	#endif

	return theAnswer;
}

inline UInt64	CAHostTimeBase::ConvertFromNanos(UInt64 inNanos)
{
	pthread_once(&sIsInited, Initialize);

	UInt64 theAnswer = MultiplyByRatio(inNanos, sToNanosDenominator, sToNanosNumerator);
	#if CoreAudio_Debug
		if(((sToNanosDenominator > sToNanosNumerator) && (theAnswer < inNanos)) || ((sToNanosNumerator > sToNanosDenominator) && (theAnswer > inNanos)))
		{
			DebugPrintf("CAHostTimeBase::ConvertFromNanos: The conversion wrapped");
		}
	#endif

	return theAnswer;
}

inline UInt64	CAHostTimeBase::GetCurrentTimeInNanos()
{
	return ConvertToNanos(GetTheCurrentTime());
}

inline UInt64	CAHostTimeBase::AbsoluteHostDeltaToNanos(UInt64 inStartTime, UInt64 inEndTime)
{
	UInt64 theAnswer;

	if(inStartTime <= inEndTime)
	{
		theAnswer = inEndTime - inStartTime;
	}
	else
	{
		theAnswer = inStartTime - inEndTime;
	}

	return ConvertToNanos(theAnswer);
}

inline SInt64	CAHostTimeBase::HostDeltaToNanos(UInt64 inStartTime, UInt64 inEndTime)
{
	SInt64 theAnswer;
	SInt64 theSign = 1;

	if(inStartTime <= inEndTime)
	{
		theAnswer = static_cast<SInt64>(inEndTime - inStartTime);
	}
	else
	{
		theAnswer = static_cast<SInt64>(inStartTime - inEndTime);
		theSign = -1;
	}

	return theSign * static_cast<SInt64>(ConvertToNanos(static_cast<UInt64>(theAnswer)));
}

inline UInt64	CAHostTimeBase::MultiplyByRatio(UInt64 inMuliplicand, UInt32 inNumerator, UInt32 inDenominator)
{
#if TARGET_OS_MAC && TARGET_RT_64_BIT
	__uint128_t theAnswer = inMuliplicand;
#else
	long double theAnswer = inMuliplicand;
#endif
	if(inNumerator != inDenominator)
	{
		theAnswer *= inNumerator;
		theAnswer /= inDenominator;
	}
	return static_cast<UInt64>(theAnswer);
}

#endif