Tree generator

$result = $this->db->get('tbl_name')->result_array();
$tree = getTree($result);

if (!function_exists('getTree')) {

    function getTree($array, $id_key = 'id', $parent_id_key = 'p_id', $weight_key = 'order') {
        foreach ($array as $index => $element)
            $array[$index]['children'] = getChildren($element[$id_key], $parent_id_key, $id_key, $weight_key, $array);
        foreach ($array as $index => $element)
            if ($element[$parent_id_key] > 0)
                unset($array[$index]);
        return $array;
    }

}

if (!function_exists('getChildren')) {

    function getChildren($parent_id_value, $parent_id_key, $id_key, $weight_key, $array) {
        if (!is_array($array))
            return false;
        $children = array();
        foreach ($array as $key => $item) {
            if ($item[$parent_id_key] == $parent_id_value) {
                $weight = $item[$weight_key];
                while (isset($children[$weight]))
                    $weight++;
                $children[$weight] = $item;
            }
        }
        foreach ($children as $key => $child) {
            $children[$key]['children'] = getChildren($child[$id_key], $parent_id_key, $id_key, $weight_key, $array);
        }
        ksort($children);
        return $children;
    }

}