CAllXDILFScheme::IsSecureUrl

static function IsSecureUrl($url)
{
	$url = trim(strval($url));
	$colonOffset = mb_strpos($url, ':');
	if($colonOffset === false)
	{
		$colonOffset = -1;
	}

	$slashOffset = mb_strpos($url, '/');
	if($slashOffset === false)
	{
		$slashOffset = -1;
	}

	$scheme = (
	$colonOffset > 0
	&& ($slashOffset < 0 || $colonOffset < $slashOffset)
		? mb_strtolower(mb_substr($url, 0, $colonOffset))
		: ''
	);

	return $scheme === '' || preg_match('/^(?:(?:ht|f)tp(?:s)?){1}/i', $scheme) === 1;
}