Reference Time

GBClock.swift

class GBClock {
    var referenceDate = NSDate(timeIntervalSinceReferenceDate: 0)
    var referenceDateInterval: NSTimeInterval { referenceDate.timeIntervalSinceReferenceDate }

    func currentTime() → NSDate {
        return NSDate(timeIntervalSinceNow: referenceDateInterval)
    }
}