php树形结构读取

<?php
// 从数组转换,操作无限分类数组.
// 数组格式, array(array('cid', 'pid', 'val'), array('cid', 'pid', 'val'));
class tree_array {
    var $data = array();
    var $child = array();
    var $layer = array();
    var $parent = array();

    // $array, 被操纵的数组, $cid 分类 id 的key. $pid 父分类 id 的key. $value 数据的 key
    function tree_array($array = array(), $cid = 'cid', $pid = 'pid', $value = null) {
        if(!is_array($array)) return false;
        foreach($array as $v) {
            if(isset($v[$value])) {
                $this->setNode($v[$cid], $v[$pid], $v[$value]);
            }
            else
            {
                $this->setNode($v[$cid], $v[$pid], $v);
            }
        }
    }
    function setNode($id, $parent, $value){
        $parent = $parent ? $parent : 0;
        $this->data[$id] = $value;
        // if(!isset($this->child[$id])) $this->child[$id] = array();
        if(!isset($this->child[$parent])) $this->child[$parent] = array();
        $this->child[$parent][] = $id;
        $this->parent[$id] = $parent;
    }

    function getValue($id) {
        if(!isset($this->data[$id])) return false;
        return $this->data[$id];
    }

    function getLayer($id, $space = false) {
        if(!isset($this->parent[$id])) return false;
        $layer = count($this->getParents($id)) + 1;
        return $space ? str_repeat($space, $layer) : $layer;
    }

    function getTreeList(&$tree, $root= 0, $space=null) {
        if(!isset($this->child[$root])) return false;
        foreach($this->child[$root] as $key=>$id) {
            if($space) {
                $tree[$id] = $this->getLayer($id, $space) . $this->data[$id];
            }
            else
            {
                $tree[$id] = $this->data[$id];
            }
            if(isset($this->child[$id])) $this->getTreeList($tree, $id, $space);
        }
    }

    function getParent($id) {
        if(!isset($this->parent[$id])) return false;
        $tid = $this->parent[$id];
        if(!$tid) return 0;
        return array($tid => $this->data[$tid]);
    }

    function getParents($id) {
        if(!isset($this->parent[$id])) return false;
        $parents = array();
        while($this->parent[$id]){
            $id = $this->parent[$id];
            $parents[$id] = $this->data[$id];
        }
        return $parents;
    }
    function getChild($id) {
        if(!isset($this->child[$id])) return false;
        $array = array();
        foreach($this->child[$id] as $v) {
            $array[$v] = $this->data[$v];
        }
        return $array;
    }

    function getChilds($id = 0) {
        if(!isset($this->child[$id])) return false;
        $child = array();
        $this->getTreeList($child, $id);
        return $child;
    }

    function html_options($id = 0, $space='　',$layer=0) {
        static $layer;
        if(!isset($this->child[$id])) return false;
        $tree = array();
        foreach($this->child[$id] as $key=>$id) {
            if($space) {
                $tree[$id] =(str_repeat($space, $layer)) . $this->data[$id];
            }
            else
            {
                $tree[$id] = $this->data[$id];
            }
            if(isset($this->child[$id])) {
                $layer++;
                $tree += $this->html_options($id, $space,$layer);
                $layer--;
            }
        }
        return $tree;
    }
}