benchmarker.swift

// https://gist.github.com/jstn/d93c86f7bd2b6f22f0bf
/*
  var b = Benchmarker()
  b.start()
  // do something
  b.stop()
  println("took \(b.milliseconds) ms")
*/

import Darwin

struct Benchmarker {
  static var t = mach_timebase_info(numer: 0, denom: 0)
  var startTime = UInt64(0)
  var duration = UInt64(0)

  var milliseconds: Double {
    return Double(duration) / 1_000_000
  }

  init() {
    if Benchmarker.t.denom == 0 {
      mach_timebase_info(&Benchmarker.t)
    }
  }

  mutating func start() {
    startTime = mach_absolute_time()
  }

  mutating func stop() {
    let delta = mach_absolute_time() - startTime
    duration = (delta * UInt64(Benchmarker.t.numer)) / UInt64(Benchmarker.t.denom)
  }
}