How to get query params and parameters in url?

examine we have this : 'path' => 'download/file/([0-9]+)/{name}',

how we can get these parameters in function ? 
```

function create_routes_customs( $router ) {	
	$router->add_route('download', array(
		'path' => 'download/file/([0-9]+)/{name}',
		'access_callback' => true,      
		'page_callback' => 'download'
	));
}

function download(){
//get params
}
```