generate gz archive

function tar_gz($source, $destination)
{
    if (extension_loaded('zlib')) {
        if (is_file($source)) {
            $file = basename($source);
            $source = dirname($source);
        } else {
            $file = basename($destination);
            $source = $source;
        }
        if (!file_exists("$destination/$file.gz")) {
            $destination = dirname($destination);
            if (!extension_loaded('zlib')) {
                return false;
            }
            $archive = new PharData("$source/$file");
            $archive->compress(Phar::GZ);
            unset($archive);
            rename("$source/$file.gz", "$destination/$file.gz");
            return "$destination/$file.gz";
        }
    }
    return false;
}