//

//  DateUtils.m

//  Cloudy

//

//  Created by Jens Alfke on 3/25/08.

//  Copyright 2008 __MyCompanyName__. All rights reserved.

//

#import "DateUtils.h"

#include <assert.h>

#include <CoreServices/CoreServices.h>

#include <mach/mach.h>

#include <mach/mach_time.h>

#include <unistd.h>

/** Absolute time (since 'reference date') to NSDate. 0.0 -> nil. */

NSDate* $date( CFAbsoluteTime time )

{

    CAssert(time>=0.0 && time < 1.0e15, @"Bogus timestamp %g",time);

    return time ?[NSDate dateWithTimeIntervalSinceReferenceDate: time] :nil;

}

/** NSDate to absolute time (since 'reference date'). nil -> 0.0 */

CFAbsoluteTime $time( NSDate* date )

{

    return date ?[date timeIntervalSinceReferenceDate] :0.0;

}

NSTimeInterval TimeIntervalSinceBoot(void)

{

    // From http://developer.apple.com/qa/qa2004/qa1398.html

    uint64_t abstime = mach_absolute_time();

    // Have to do some pointer fun because AbsoluteToNanoseconds

    // works in terms of UnsignedWide, which is a structure rather

    // than a proper 64-bit integer.

    Nanoseconds elapsedNano = AbsoluteToNanoseconds( *(AbsoluteTime *) &abstime );

    return *(uint64_t*)&elapsedNano / 1.0e9;

}