ROT13 in Swift with Emoji support 😍

ROT13.swift

//: Playground - noun: a place where people can play

// Converts a string into it's ROT13 equavalent. Note, this is not a secure way (at all) to encrypt private data.
// Please look into BCRYPT or something similar for sensistive data

extension String {
  var encrypt: String {
    return self.run(self, rotateAmount: 13)
  }
  var decrypt: String {
    return self.run(self, rotateAmount: -13)
  }
  func run(str:String, rotateAmount:Int) -> String {
    return "".join(str.characters.map {
        (char) -> String in
        let num = String(char).unicodeScalars
        let characterIntVal = num.first!.value
        let rotatedIntVal = Int(characterIntVal) + rotateAmount
        let newStringValue = String(UnicodeScalar(rotatedIntVal))
        return newStringValue
      }
    )
  }
}

let str = "Woot! Orange cats are the best 😍. If you like cats, that is."

"Encrypted:"
let encrypted = str.encrypt

"Decrypted:"
let decrpyed = encrypted.decrypt

i believe the lowest int value will be 'a' which is 65 if i remember correctly. This seems great, but I'm wondering about characters with Int values less than the rotated amount.

@kocodude I move things ahead by 13 now (rather than backwards, that was a typo in the last rev), so unless you’re at the very last character in unicode, you should always have room to move forward.