PHP directory traversal tree

dirTree

<?php

$array = array(); 
$lastDepth = 0;
$dirStack = array();

foreach ($iterator = new RecursiveIteratorIterator(
    new RecursiveDirectoryIterator("./", 
        RecursiveDirectoryIterator::SKIP_DOTS),
    RecursiveIteratorIterator::SELF_FIRST) as $item) {
    // Note SELF_FIRST, so array keys are in place before values are pushed.
	$currentDepth = $iterator -> getDepth();
    $subPath = $iterator->getSubPathName();
	//$value = preg_rdeplace("~".end($dirStack)."/~", "", $subPath, 1);
	if($item->isDir()) {
		// Create a new array key of the current directory name.
		$array[$subPath] = array();
		$lastDepth = $currentDepth;
		$dirStack[] = $subPath;
		
	}
	else { 
       	// Add a new element to the array of the current file name.
        //$array[] = $subPath;
		if($lastDepth > $currentDepth) {
			$lastDepth = $currentDepth;
			array_pop($dirStack);
		} else {
			switch(count($dirStack)) {
				case 1: {
					$value = preg_replace("/".end($dirStack)."/", "", $subPath, 1);
					$array[end($dirStack)][] = $value;
					break;
				}
				case 2: {
					$realPath = preg_replace("~".$iterator->getSubPath()."~", "", $subPath, 1);
					$realPath = end($dirStack).$realPath;
					$array[$dirStack[0]][end($dirStack)][] = $realPath;
					break;
				}
				case 3: {
					$realPath = preg_replace("~".$iterator->getSubPath()."~", "", $subPath, 1);
					$realPath = end($dirStack).$realPath;
					$array[$dirStack[0]][$dirStack[1]][end($dirStack)][] = $realPath;
					break;
				}
				default: $array[] = $subPath;
			}
		}
    }
}

unset($array[0]);

$array = array_filter($array);

function printDir($array, $k = null) {
	foreach ($array as $key => $item) {
		if(is_array($item)) {
			$name = preg_replace("~".$k."~", "", $key, 1);
			$name = preg_replace("~/~", "", $name, 1);
			echo "<li><a href=\"./".$key."\">".$name."</a></li><ul>";
			printDir($item, $key);
			echo "</ul>";
		} else {
			$value = $item;
			$name = preg_replace("~".$k."~", "", $item, 1);
			$name = preg_replace("~/~", "", $name, 1);
			echo "<li><a href=\"./".$item."\">".$name."</a></li>";
		}
	}
}
?>

<!-- to show tree -->
<ul>
<?php printDir($array); ?>
</ul>