/*
     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
