PHPでのエスケープunescapeの実装方法

function escape($str) {
preg_match_all("/[x80-xff].|[x01-x7f] /",$str,$r); 
$ar = $r[0]; 
foreach($ar as $k=>$v) {
if(ord($v[0]) < 128)
$ar[$k] = rawurlencode($v); 
else
$ar[$k] = "%u".bin2hex(iconv("GB2312","UCS-2",$v)); 
}
return join("",$ar); 
}

function unescape($str) {
$str = rawurldecode($str); 
preg_match_all("/(?:%u.{4})|./",$str,$r); 
$ar = $r[0]; 
foreach($ar as $k=>$v) {
if(substr($v,0,2) == "%u" && strlen($v) == 6)
$ar[$k] = iconv("UCS-2","GB2312",pack("H4",substr($v,-4))); 
}
return join("",$ar); 
}