Should be the same than the original get_headers():

<?php
if (!function_exists('get_headers')) {
function get_headers($url, $format=0) {
    $headers = array();
    $url = parse_url($url);
    $host = isset($url['host']) ? $url['host'] : '';
    $port = isset($url['port']) ? $url['port'] : 80;
    $path = (isset($url['path']) ? $url['path'] : '/') . (isset($url['query']) ? '?' . $url['query'] : '');
    $fp = fsockopen($host, $port, $errno, $errstr, 3);
    if ($fp)
    {
        $hdr = "GET $path HTTP/1.1\r\n";
        $hdr .= "Host: $host \r\n";
        $hdr .= "Connection: Close\r\n\r\n";
        fwrite($fp, $hdr);
        while (!feof($fp) && $line = trim(fgets($fp, 1024)))
        {
            if ($line == "\r\n") break;
            list($key, $val) = explode(': ', $line, 2);
            if ($format)
                if ($val) $headers[$key] = $val;
                else $headers[] = $key;
            else $headers[] = $line;
        }
        fclose($fp);
        return $headers;
    }
    return false;
}
}
?>