//
//  SPDateAdditions.m
//  sequel-pro
//
//  Created by Rowan Beentje (rowan.beent.je) on February 22, 2012.
//  Copyright (c) 2012 Rowan Beentje. All rights reserved.
//
//  Permission is hereby granted, free of charge, to any person
//  obtaining a copy of this software and associated documentation
//  files (the "Software"), to deal in the Software without
//  restriction, including without limitation the rights to use,
//  copy, modify, merge, publish, distribute, sublicense, and/or sell
//  copies of the Software, and to permit persons to whom the
//  Software is furnished to do so, subject to the following
//  conditions:
//
//  The above copyright notice and this permission notice shall be
//  included in all copies or substantial portions of the Software.
//
//  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
//  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
//  OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
//  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
//  HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
//  WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
//  FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
//  OTHER DEALINGS IN THE SOFTWARE.
//
//  More info at <https://github.com/sequelpro/sequelpro>

#include <mach/mach_time.h>
#include "SPDateAdditions.h"

@implementation NSDate (SPDateAdditions)

/**
 * Retrieve a monotonic time for timing purposes: a value of a number of seconds
 * which can be use for relative time comparison in a monotonic sense, eg in a 
 * particular session this value will only ever increase linearly.
 * This differs from (for example) unix epoch timestamps or dates, which can change
 * when the system time changes or synchs, but should never be used for absolute time
 * as it is based on the elapsed time since the system booted.
 */
+ (uint64_t)monotonicTime
{
    return clock_gettime_nsec_np(CLOCK_MONOTONIC);
}

+ (NSTimeInterval)timeIntervalSinceMonotonicTime:(uint64_t)comparisonTime
{
	uint64_t timeElapsed = [self monotonicTime] - comparisonTime;
	return (NSTimeInterval)(timeElapsed * 1e-9);
}

@end
