Help with filter!

[Superian]

I am trying to write a script that checks whether a string is valid UTF-8, but I have no idea where to start. Any ideas? Thanks!

[Superian]

How could I make this into one function instead of having to use two?

 

<?php
function check_plain($text) {
  return _validate_utf8($text) ? htmlspecialchars($text, ENT_QUOTES) : '';
}

function _validate_utf8($text) {
  if (strlen($text) == 0) {
    return TRUE;
  }
  return (preg_match('/^./us', $text) == 1);
}
?>

[discomatt]

http://www.php.net/manual/en/function.mb-detect-encoding.php