Data commit

Task/Time-a-function/Swift/time-a-function.swift

@@ -0,0 +1,56 @@
+import Foundation
+
+public struct TimeResult {
+  public var seconds: Double
+  public var nanoSeconds: Double
+
+  public var duration: Double { seconds + (nanoSeconds / 1e9) }
+
+  @usableFromInline
+  init(seconds: Double, nanoSeconds: Double) {
+    self.seconds = seconds
+    self.nanoSeconds = nanoSeconds
+  }
+}
+
+extension TimeResult: CustomStringConvertible {
+  public var description: String {
+    return "TimeResult(seconds: \(seconds); nanoSeconds: \(nanoSeconds); duration: \(duration)s)"
+  }
+}
+
+public struct ClockTimer {
+  @inlinable @inline(__always)
+  public static func time<T>(_ f: () throws -> T) rethrows -> (T, TimeResult) {
+    var tsi = timespec()
+    var tsf = timespec()
+
+    clock_gettime(CLOCK_MONOTONIC_RAW, &tsi)
+    let res = try f()
+    clock_gettime(CLOCK_MONOTONIC_RAW, &tsf)
+
+    let secondsElapsed = difftime(tsf.tv_sec, tsi.tv_sec)
+    let nanoSecondsElapsed = Double(tsf.tv_nsec - tsi.tv_nsec)
+
+    return (res, TimeResult(seconds: secondsElapsed, nanoSeconds: nanoSecondsElapsed))
+  }
+}
+
+func ackermann(m: Int, n: Int) -> Int {
+  switch (m, n) {
+  case (0, _):
+    return n + 1
+  case (_, 0):
+    return ackermann(m: m - 1, n: 1)
+  case (_, _):
+    return ackermann(m: m - 1, n: ackermann(m: m, n: n - 1))
+  }
+}
+
+let (n, t) = ClockTimer.time { ackermann(m: 3, n: 11) }
+
+print("Took \(t.duration)s to calculate ackermann(m: 3, n: 11) = \(n)")
+
+let (n2, t2) = ClockTimer.time { ackermann(m: 4, n: 1) }
+
+print("Took \(t2.duration)s to calculate ackermann(m: 4, n: 1) = \(n2)")