wp_parse_auth_cookie( string $cookie = '', string $scheme = '' )

function wp_parse_auth_cookie($cookie = '', $scheme = '') {
	if ( empty($cookie) ) {
		switch ($scheme){
			case 'auth':
				$cookie_name = AUTH_COOKIE;
				break;
			case 'secure_auth':
				$cookie_name = SECURE_AUTH_COOKIE;
				break;
			case "logged_in":
				$cookie_name = LOGGED_IN_COOKIE;
				break;
			default:
				if ( is_ssl() ) {
					$cookie_name = SECURE_AUTH_COOKIE;
					$scheme = 'secure_auth';
				} else {
					$cookie_name = AUTH_COOKIE;
					$scheme = 'auth';
				}
	    }

		if ( empty($_COOKIE[$cookie_name]) )
			return false;
		$cookie = $_COOKIE[$cookie_name];
	}

	$cookie_elements = explode('|', $cookie);
	if ( count( $cookie_elements ) !== 4 ) {
		return false;
	}

	list( $username, $expiration, $token, $hmac ) = $cookie_elements;

	return compact( 'username', 'expiration', 'token', 'hmac', 'scheme' );
}