/**
@function QPHeader
Encodes given string as a quoted printable mail header.
@param str string String to encode
@return string
*/
public static function QPHeader($str, $charset = 'UTF-8')
{
if (!preg_match('/[^\\x00-\\x3C\\x3E-\\x7E]/', $str)) {
return $str;
}
return '=?' . $charset . '?Q?' . text::QPEncode($str) . '?=';
}
