Swift: encode non-ascii characters as utf8 hex

encoding.swift

import Foundation

extension Character {
    var asciiValue: UInt32? {
        return String(self).unicodeScalars.filter{$0.isASCII}.first?.value
    }
}

func encodeNonASCIIAsUTF8Hex(toEncode: String) -> String{
    var result = ""
    for character in toEncode.characters {
        if character.asciiValue != nil {
            result.append(character)
        } else {
            for byte in String(character).utf8 {
                result.append("\\x" + (NSString(format:"%2X", byte) as String))
            }
        }
    }
    return result
}

encodeNonASCIIAsUTF8Hex(toEncode: "Josh Broomberg’s iPhone")