Swift Foundation.Data Benchmark

DataSpeedTest.swift

import Foundation

let n: Int
if CommandLine.arguments.count > 3, let int = Int(CommandLine.arguments[3]) {
	n = 1 << int
} else {
	n = 1 << 26
	guard CommandLine.arguments.count >= 3 else {
		print("Usage: \(CommandLine.arguments[0]) datastructure test [log(iterations)]")
		exit(EXIT_FAILURE)
	}
}

protocol InitRepeatingCollection: Collection {
	init(repeating: Element, count: Int)
}

extension Data: InitRepeatingCollection {}
extension Array: InitRepeatingCollection {}

func stringTest<C: Collection>(_ col: C) where C.Element == UInt8 {
	let string = String(decoding: col, as: UTF8.self)
	print(string.last!)
}

func reduceTest<C: Collection>(_ col: C) where C.Element == UInt8 {
	print(col.reduce(0, { $0 + Int($1) }))
}

func sliceTest<C: Collection>(_ col: C) where C.Element == UInt8 {
	var slice = col[...]
	var count = 0
	var total = 0
	while !slice.isEmpty {
		total += Int(slice.first!)
		count += 1
		slice = slice[slice.index(after: slice.startIndex)...]
	}
	print(count)
	print(total)
}

func forTest<C: Collection>(_ col: C) where C.Element == UInt8 {
	var count = 0
	var total = 0
	for item in col {
		count += 1
		total += Int(item)
	}
	print(count)
	print(total)
}

func allocTest<C: InitRepeatingCollection>(_ type: C.Type, n: Int) where C.Element == UInt8 {
	let c = (0..<n).map({ _ in C(repeating: 97, count: 32) })
	print(c[0])
}

func test<C: InitRepeatingCollection>(_ type: C.Type, testName: String, n: Int) where C.Element == UInt8 {
	if testName == "alloc" {
		allocTest(C.self, n: n)
	} else {
		let col = C(repeating: 97 /* ASCII a */, count: n)
		
		switch testName {
		case "reduce": reduceTest(col)
		case "string": stringTest(col)
		case  "slice": sliceTest(col)
		case    "for": forTest(col)
		default: print("Unsupported test")
		}
	}
}

let testName = CommandLine.arguments[1].lowercased()
switch CommandLine.arguments[2].lowercased() {
case "array":
	test([UInt8].self, testName: testName,  n: n)
case "data":
	test(Data.self, testName: testName, n: n)
default:
	print("Unsupported data structure")
}