get top level domain by php

function rLastParse($str, $sep, $cnt = 1, $complete_if_not = false){ $i = strrpos($str, $sep); while (($cnt > 1) && ($i !== false)) {  $i = strrpos(substr($str, 0, $i), $sep);  $cnt--; } if ($i === false) {  return $complete_if_not ? $str : ‘‘; } else {  return substr($str, $i + strlen($sep)); }}

function getTopLevelDomain(){ if(isset($_SERVER[‘HTTP_X_FORWARDED_HOST‘]) && !empty($_SERVER[‘HTTP_X_FORWARDED_HOST‘])){  $host = $_SERVER[‘HTTP_X_FORWARDED_HOST‘]; } else{  $host = $_SERVER[‘HTTP_HOST‘]; } return rLastParse($host, DOT);}