Unicode defines a name and a number of all of the glyphs it
  encompasses: the numbers are called code points: they run from
  0 to 0x10FFFF.
  
  utf8ToInt converts a length-one character string encoded in
  UTF-8 to an integer vector of Unicode code points.  It checks validity
  of the input and returns NA if it is invalid.
intToUtf8 converts a numeric vector of Unicode code points
  either to a single character string or a character vector of single
  characters.  (For a single character string 0 is silently
  omitted: otherwise 0 is mapped to "".  Non-integral
  numeric values are truncated to integers.)  The Encoding
  is declared as "UTF-8".
NA inputs are mapped to NA output.