Struct Execution Time Experiment

//
//  main.swift
//  StructSize
//
//  Created by James Campbell on 20/04/2020.
//  Copyright © 2020 James Campbell. All rights reserved.
//

import Foundation
import AppKit

struct CellA {
    var borderWidth: Int {4}
}

struct CellB {
    var borderWidth: Int = 4
}

struct CellC {
    static var borderWidth: Int = 4
}

struct CellD {
    static var _borderWidth: Int = 4
    var borderWidth: Int { Self._borderWidth }
}

struct CellE {
    static var _borderWidth: Int = 4
    var borderWidth: Int = Self._borderWidth
}

func measureExecutionTime(label: String, subject: () -> Void) {
    let operationsPerTrial = 100_000_000
    var minTime = Double.infinity
    print("\(label):")
    for _ in 0 ..< operationsPerTrial {

        let t0 = CACurrentMediaTime()
        subject()
        
        let t1 = CACurrentMediaTime()
        let time = t1 - t0
        print("  time:", time, "seconds")
        minTime = min(minTime, time)
    }
    print("  minimum time:", minTime, "seconds\n")
}

let cellA = {
    let c = CellA()
    _ = c.borderWidth + 1
}

let cellB = {
    let c = CellB()
    _ = c.borderWidth + 1
}

let cellC = {
    _ = CellC.borderWidth + 1
}

let cellD = {
    let c = CellD()
    _ = c.borderWidth + 1
}

measureExecutionTime(label: "Cell A", subject: cellA)
measureExecutionTime(label: "Cell B", subject: cellB)
measureExecutionTime(label: "Cell C", subject: cellC)
measureExecutionTime(label: "Cell D", subject: cellD)