An interval timer.

IntervalTimer.swift

class IntervalTimer {
    
    enum Status { case STARTED, STOPPED, PAUSED }
    
    var duration: Float = 0.0
    var startTime: Float = 0.0
    var fraction: Float = 0.0
    var isLoop: Bool = false
    var status: Status = .STOPPED
    
    func setDuration(sec: Float) {
        duration = sec
        if duration < 0.0 {
            duration = 0.0
        }
    }
    
    func getDuration() -> Float {
        return duration
    }
    
    func setLoop(isLoop: Bool) {
        self.isLoop = isLoop
    }
    
    func getLoop() -> Bool {
        return self.isLoop
    }
    
    func start(sec: Float) {
        if status == .STOPPED {
            fraction = 0.0
            startTime = sec
        }
        else {
            if status == .PAUSED {
                startTime = sec - fraction * duration
            } else {
                if duration >= FLT_EPSILON {
                    startTime = sec - fraction * duration
                }
                else {
                    startTime = sec
                }
            }
        }
        
        status = .STARTED
    }
    
    func stop() {
        status = .STOPPED
        fraction = 0.0
    }
    
    func pause() {
        status = .PAUSED
    }
    
    func update(sec: Float) {
        
        if status == .STOPPED || status == .PAUSED {
            return
        }
        
        if duration < FLT_EPSILON {
            fraction = 0.0
        } else {
            fraction = (sec - startTime) / duration
            if (isLoop) {
                fraction = fraction - floorf(fraction);
            } else {
                if fraction > 1.0 {
                    fraction = 1.0
                }
            }
        }
    }
    
    func getFraction() -> Float {
        return fraction
    }
    func getStatus() -> Status {
        return status
    }
    
    func isComplete() -> Bool {
        return !isLoop && fraction >= 1.0
    }
}