PHP截断标题且兼容utf8和gb2312编码

<?php if(strlen($r[title])>45){$str=utf8Substr($r[title],0,15)."...";}else{$str=$r[title];}echo $str; ?> 
//截取utf8字符串 
function utf8Substr($str, $from, $len) 
{ 
return preg_replace('#^(?:[\x00-\x7F]|[\xC0-\xFF][\x80-\xBF]+){0,'.$from.'}'. 
'((?:[\x00-\x7F]|[\xC0-\xFF][\x80-\xBF]+){0,'.$len.'}).*#s', 
'$1',$str); 
}