<?php
/**
 * get_redirect_url()
 * Gets the address that the provided URL redirects to,
 * or FALSE if there's no redirect. 
 *
 * @param string $url
 * @return string
 */
function get_redirect_url($url){
	$redirect_url = null; 
 
	$url_parts = @parse_url($url);
	if (!$url_parts) return false;
	if (!isset($url_parts['host'])) return false; //can't process relative URLs
	if (!isset($url_parts['path'])) $url_parts['path'] = '/';
 
	$sock = fsockopen($url_parts['host'], (isset($url_parts['port']) ? (int)$url_parts['port'] : 80), $errno, $errstr, 30);
	if (!$sock) return false;
 
	$request = "HEAD " . $url_parts['path'] . (isset($url_parts['query']) ? '?'.$url_parts['query'] : '') . " HTTP/1.1\r\n"; 
	$request .= 'Host: ' . $url_parts['host'] . "\r\n"; 
	$request .= "Connection: Close\r\n\r\n"; 
	fwrite($sock, $request);
	$response = '';
	while(!feof($sock)) $response .= fread($sock, 8192);
	fclose($sock);
 
	if (preg_match('/^Location: (.+?)$/m', $response, $matches)){
		if ( substr($matches[1], 0, 1) == "/" )
			return $url_parts['scheme'] . "://" . $url_parts['host'] . trim($matches[1]);
		else
			return trim($matches[1]);
 
	} else {
		return false;
	}
 
}
 
/**
 * get_all_redirects()
 * Follows and collects all redirects, in order, for the given URL. 
 *
 * @param string $url
 * @return array
 */
function get_all_redirects($url){
	$redirects = array();
	while ($newurl = get_redirect_url($url)){
		if (in_array($newurl, $redirects)){
			break;
		}
		$redirects[] = $newurl;
		$url = $newurl;
	}
	return $redirects;
}
 
/**
 * get_final_url()
 * Gets the address that the URL ultimately leads to. 
 * Returns $url itself if it isn't a redirect.
 *
 * @param string $url
 * @return string
 */
function get_final_url($url){
	$redirects = get_all_redirects($url);
	if (count($redirects)>0){
		return array_pop($redirects);
	} else {
		return $url;
	}
}

$rez = get_all_redirects('http://dw.com.com/redir?edId=3&siteId=4&oId=3000-2367_4-10207484&ontId=2367_4&spi=2cc5cc690f5f02260022cc699c6324f8&lop=link&tag=tdw_dltext&ltype=dl_dlnow&pid=11128235&mfgId=61635&merId=61635&pguid=Qpq0pwoPjAMAAAuGp3YAAACe&destUrl=http%3A%2F%2Fdownload.cnet.com%2F3001-2367_4-10207484.html%3Fspi%3D2cc5cc690f5f02260022cc699c6324f8');
print_r($rez);
?>