    def encode_string(value, _)
      location = encode_uint(@inputs ? size_of_inputs(@inputs) + @tail.size/2 : 32)
      size = encode_uint(value.bytes.size)
      content = value.bytes.map {|x| x.to_s(16).rjust(2, '0')}.join("").ljust(64, '0')
      [location, size + content]
    end