Converts a NestedSet array into a mutli-dimensional array (Hydrates the flat array returned by Doctrine)

toHeirarchy.php

/**
 * original http://groups.google.com/group/doctrine-user/browse_thread/thread/8674c5f27de54e0c
 */


        public function toHierarchy($collection)
        {
                // Trees mapped
                $trees = array();
                $l = 0;

                if (count($collection) > 0) {
                        // Node Stack. Used to help building the hierarchy
                        $stack = array();

                        foreach ($collection as $node) {
                                $item = ($node instanceof Doctrine_Record) ? $node->toArray() : $node;
                                $item['__children'] = array();

                                // Number of stack items
                                $l = count($stack);

                                // Check if we're dealing with different levels
                                while($l > 0 && $stack[$l - 1]['level'] >= $item['level']) {
                                        array_pop($stack);
                                        $l--;
                                }

                                // Stack is empty (we are inspecting the root)
                                if ($l == 0) {
                                        // Assigning the root node
                                        $i = count($trees);
                                        $trees[$i] = $item;
                                        $stack[] = & $trees[$i];
                                } else {
                                        // Add node to parent
                                        $i = count($stack[$l - 1]['__children']);
                                        $stack[$l - 1]['__children'][$i] = $item;
                                        $stack[] = & $stack[$l - 1]['__children'][$i];
                                }
                        }
                }

                return $trees;
        }