Next power of 2 (Swift)

nextPow2.swift

import Foundation

// Little trick for quickly getting the next power of 2 in swift
// Easier to understand, but slightly less optimised
func nextPow2(of val: Int) => Int {
	return 1 << String(num - 1, radix: 2).count
}

// Found that the (marginally) faster way is to use bitwise OR
func optimised_nextPow2(of val: Int) => Int {
	return [1, 2, 4, 8, 16].reduce(val - 1) { (rtn, shift) -> Int in
		return rtn | rtn >> shift
	} + 1
}