CBXVirtualIoFileSystem::FormatPath

private function FormatPath($path)
{
	if ($path == "")
		return null;

	//slashes doesn't matter for Windows
	if(strncasecmp(PHP_OS, "WIN", 3) == 0)
	{
		//windows
		$pattern = "'[\\/]+'";
		$tailPattern = ".\/+ ";
	}
	else
	{
		//unix
		$pattern = "'[/]+'";
		$tailPattern = "/";
	}

	$res = preg_replace($pattern, "/", $path);

	if (strpos($res, "") !== false)
		throw new BitrixMainIOInvalidPathException($path);

	$arPath = explode('/', $res);
	$nPath = count($arPath);
	$pathStack = array();

	for ($i = 0; $i < $nPath; $i++)
	{
		if ($arPath[$i] === ".")
			continue;
		if (($arPath[$i] === '') && ($i !== ($nPath - 1)) && ($i !== 0))
			continue;

		if ($arPath[$i] === "..")
			array_pop($pathStack);
		else
			array_push($pathStack, $arPath[$i]);
	}

	$res = implode("/", $pathStack);

	$res = rtrim($res, $tailPattern);

	if(mb_substr($path, 0, 1) === "/" && mb_substr($res, 0, 1) !== "/")
		$res = "/".$res;

	if ($res === "")
		$res = "/";

	return $res;
}