virtual key codes to unicode characters

translatekeycodes.swift

   func keyCodeToString(keyCode: CGKeyCode) -> String {
      let curKeyboard = TISCopyCurrentKeyboardInputSource().takeRetainedValue()
      let ptr = TISGetInputSourceProperty(curKeyboard, kTISPropertyUnicodeKeyLayoutData)
      let keyboardLayoutPtr = UnsafePointer<UCKeyboardLayout>(ptr)

      var deadKeyState: UInt32 = 0
      var actualStringLength = 0
      var unicodeString = [UniChar](count: 255, repeatedValue: 0)

      let status = UCKeyTranslate(keyboardLayoutPtr,
                                  keyCode,
                                  UInt16(kUCKeyActionDown),
                                  0,
                                  UInt32(LMGetKbdType()),
                                  0,
                                  &deadKeyState,
                                  255,
                                  &actualStringLength,
                                  &unicodeString)

      print("Status Error: \(status != noErr)")
      print("Param  Error: \(status == Int32(paramErr))")

      return NSString(characters: unicodeString, length: actualStringLength) as String
   }