PublicUtility/CAHostTimeBase.h
/* |
File: CAHostTimeBase.h |
Abstract: Part of CoreAudio Utility Classes |
Version: 1.01 |
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*/ |
#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> |
#elif TARGET_OS_WIN32 |
#include <windows.h> |
#else |
#error Unsupported operating system |
#endif |
#include "CADebugMacros.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() { if(!sIsInited) { Initialize(); } return sFrequency; } |
static Float64 GetInverseFrequency() { if(!sIsInited) { Initialize(); } return sInverseFrequency; } |
static UInt32 GetMinimumDelta() { if(!sIsInited) { Initialize(); } return sMinDelta; } |
static UInt64 AbsoluteHostDeltaToNanos(UInt64 inStartTime, UInt64 inEndTime); |
static SInt64 HostDeltaToNanos(UInt64 inStartTime, UInt64 inEndTime); |
private: |
static void Initialize(); |
static bool sIsInited; |
static Float64 sFrequency; |
static Float64 sInverseFrequency; |
static UInt32 sMinDelta; |
static UInt32 sToNanosNumerator; |
static UInt32 sToNanosDenominator; |
static UInt32 sFromNanosNumerator; |
static UInt32 sFromNanosDenominator; |
static bool sUseMicroseconds; |
#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) |
{ |
DebugMessageN2("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) |
{ |
if(!sIsInited) |
{ |
Initialize(); |
} |
Float64 theNumerator = static_cast<Float64>(sToNanosNumerator); |
Float64 theDenominator = static_cast<Float64>(sToNanosDenominator); |
Float64 theHostTime = static_cast<Float64>(inHostTime); |
Float64 thePartialAnswer = theHostTime / theDenominator; |
Float64 theFloatAnswer = thePartialAnswer * theNumerator; |
UInt64 theAnswer = static_cast<UInt64>(theFloatAnswer); |
//Assert(!((theNumerator > theDenominator) && (theAnswer < inHostTime)), "CAHostTimeBase::ConvertToNanos: The conversion wrapped"); |
//Assert(!((theDenominator > theNumerator) && (theAnswer > inHostTime)), "CAHostTimeBase::ConvertToNanos: The conversion wrapped"); |
return theAnswer; |
} |
inline UInt64 CAHostTimeBase::ConvertFromNanos(UInt64 inNanos) |
{ |
if(!sIsInited) |
{ |
Initialize(); |
} |
Float64 theNumerator = static_cast<Float64>(sToNanosNumerator); |
Float64 theDenominator = static_cast<Float64>(sToNanosDenominator); |
Float64 theNanos = static_cast<Float64>(inNanos); |
Float64 thePartialAnswer = theNanos / theNumerator; |
Float64 theFloatAnswer = thePartialAnswer * theDenominator; |
UInt64 theAnswer = static_cast<UInt64>(theFloatAnswer); |
//Assert(!((theDenominator > theNumerator) && (theAnswer < inNanos)), "CAHostTimeBase::ConvertToNanos: The conversion wrapped"); |
//Assert(!((theNumerator > theDenominator) && (theAnswer > inNanos)), "CAHostTimeBase::ConvertToNanos: The conversion wrapped"); |
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 = inEndTime - inStartTime; |
} |
else |
{ |
theAnswer = inStartTime - inEndTime; |
theSign = -1; |
} |
return theSign * ConvertToNanos(theAnswer); |
} |
#endif |
Copyright © 2012 Apple Inc. All Rights Reserved. Terms of Use | Privacy Policy | Updated: 2012-07-05