data+hexInit.swift

/** Extensions to Data
 */
extension Data {
  /** Create data from hex string
   */
  init(hex: String) throws {
    var bytes = Array<Byte>(repeating: Byte(), count: (hex.unicodeScalars.count + 1) >> 1)

    try hex.unicodeScalars.enumerated().forEach { index, scalar in
      var nibble = try scalar.hexNibble()

      if index & 1 == 0 { nibble <<= 4 }

      bytes[index >> 1] |= nibble
    }

    self = Data(bytes: bytes)
  }

  /** Returns data represented as a hex encoded string
   */
  var hexEncoded: String { return map { String(format: "%02hhx", $0) }.joined() }
}