http://framework.zend.com/fisheye/browse/Zend_Framework/trunk/incubator/library/Zend/Http/Response.php?r=trunk#l360
preg_match("|^HTTP/[\d\.x]+ (\d+) |", $response_str, $m);

But some web servers return a status line without Reason-Phrase field.
ex) HTTP/1.1 301
see: wget -S http://www.amazon.co.jp/exec/obidos/ASIN/4334033547/ref=nosim/

To support these servers, it will be changed like this.
Zend_Http_Response::extractCode

• preg_match("|^HTTP/[\d\.x]+ (\d+) |", $response_str, $m);
  + preg_match("|^HTTP/[\d\.x]+ (\d+)|", $response_str, $m);

Zend_Http_Response::extractVersion

• preg_match("|^HTTP/([\d\.x]+) \d+ |", $response_str, $m);
  + preg_match("|^HTTP/([\d\.x]+) \d+|", $response_str, $m);