//

 //  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;

 }