rendfall

function getRemoteFilesize($url, $formatSize = true, $useHead = true) {
    if (false !== $useHead) {
        stream_context_set_default(array('http' => array('method' => 'HEAD')));
    }

    $head = array_change_key_case(get_headers($url, 1));
    // content-length of download (in bytes), read from Content-Length: field
    $clen = isset($head['content-length']) ? $head['content-length'] : 0;

    // cannot retrieve file size, return "-1"