Infinite recursion tree display_PHP tutorial

[php]
/**
* Infinite level (limited by the tail node description algorithm, see tree_parse comment for details) recursive menu
* author: selfimpr
* blog: http://blog.csdn.net/lgg201
* mail: lgg860911@yahoo.com.cn
​*/

define('MAX_NODES', 3); /* Maximum number of child nodes */
define('MAX_NODE_INDEX', MAX_NODES - 1); /* Maximum index value of child nodes */
define('NAME_FMT', 'name-%08d'); /* Node content output format string */

/* Tree node data structure */
define('K_ID', 'id');
define('K_NAME', 'name');
define('K_CHILD', 'children');

/* Output the assembly characters used in construction */
define('PREFIX_TOP',                                                                                                                                                                                                                                                                                       through define('PREFIX_BOTTOM', '┗'); /* The identifier of the last child node of each parent node */
define('PREFIX_MIDDLE', '┠'); /* Identifiers of all nodes that are not in the above two cases */
define('PREFIX_LINE', '┇'); /* The ligature of the ancestor node */
define('SPACE',             ' ');                                                                                                                                                                                                                         define('WIDE_SPACE', str_repeat(SPACE, 4)); /* Wide blank placeholder, in order to make the hierarchy of the tree clear */


/**
* data_build
* Construct a node
* @param mixed $id Node id
* @param mixed $is_leaf Whether it is a leaf
* @access public
* @return void
​*/
function node_build($id, $is_leaf = FALSE) {
Return array(
K_ID => $id,
K_NAME => sprintf(NAME_FMT, $id),
K_CHILD => $is_leaf ? NULL : array(),
);
}
/**
* tree_build
* Construct a tree (the number of child nodes of each node in the tree is determined by MAX_NODES)
* @param mixed $datas The tree reference to be returned
* @param mixed $id Starting ID
* @param mixed $level The level of the tree
* @access public
* @return void
​*/
function tree_build(&$datas, &$id, $level) {
If ( $level < 1 ) return ;
$is_leaf = $level == 1;
$i = -1;
$next_level = $level - 1;
while ( ++ $i < MAX_NODES ) {
$data = node_build($id++, $is_leaf);
If ( !$is_leaf )
Tree_build($data[K_CHILD], $id, $next_level);
         array_push($datas, $data);
}  
}

/**
* node_str
* Output a node’s own information
 * @param mixed $string 返回结果的字符串(引用传值)
 * @param mixed $data   节点数据
 * @access public
 * @return void
 */ 
function node_str(&$string, $data) { 
    $string .= sprintf(' %s[%d]', $data[K_NAME], $data[K_ID]); 
} 
/**
* node_sign
* Output the glyph of a node
* @param mixed $string Return the string of the result (pass by value)
* @param mixed $level Current depth
* @param mixed $i The index (subscript) of the current node in the parent node
* @access public
* @return void
​*/ 
function node_sign(&$string, $level, $i) { 
    switch ( $i ) { 
        case 0: 
            $string .= $level == 0 ? PREFIX_TOP : PREFIX_MIDDLE; 
            break; 
        case MAX_NODE_INDEX: 
            $string .= PREFIX_BOTTOM; 
            break; 
        default: 
            $string .= PREFIX_MIDDLE; 
            break; 
    } 
} 
/**
* node_prefix
* Output the prefix of a node
* @param mixed $string Return the string of the result (pass by value)
* @param mixed $level Current depth
* @param mixed $is_last Whether all ancestor nodes of the current node (including) have tail node tags
* @access public
* @return void
​*/ 
function node_prefix(&$string, $level, $is_last) { 
    if ( $level > 0 ) { 
        $i  = 0; 
        /* 前缀格式: "父级连线" ["宽空白符" "父级连线" ...] "宽空白符" */ 
        $string .= ($is_last & 1 << ($level - $i) ? SPACE : PREFIX_LINE); 
        while ( ++ $i < $level )  
            $string .= WIDE_SPACE . ($is_last & 1 << ($level - $i) ? SPACE : PREFIX_LINE); 
        $string .= WIDE_SPACE; 
    } 
} 
/**
* node_out
* Output a node
* @param mixed $string Return the string of the result (pass by value)
* @param mixed $data The node data to be processed
* @param mixed $level Node depth
* @param mixed $i The index (subscript) of the node in the parent node
* @param mixed $is_last Whether all ancestor nodes of the current node (including) have tail node tags
* @access public
* @return void
​*/ 
function node_out(&$string, $data, $level, $i, $is_last) { 
    /* 处理前缀字符串: 祖先的连接符及空白 */ 
    node_prefix($string, $level, $is_last); 
    /* 处理本节点的标识符号 */ 
    node_sign($string, $level, $i); 
    /* 处理本节点数据信息 */ 
    node_str($string, $data); 
    /* 追加换行 */ 
    $string     .= "n"; 
} 
/**
 * tree_parse 
 * 输出一棵树
 *  1. 由于使用了整型的$is_last作为祖先是否尾节点的标记, 所以最多支持PHP_INT_MAX的深度
 *  2. 如果需要扩展, 修正$is_last的数据类型及校验方法即可
 * @param mixed $string 返回结果的字符串(引用传值)
 * @param mixed $datas  要处理的树数据
 * @param int $level    当前处理的深度
 * @param int $is_last  当前深度所有祖先是否尾节点标记
 * @access public
* @return void
*/
function tree_parse(&$string, $datas, $level = 0, $is_last = 0) {
If ( !is_array($datas) || count($datas) < 1 ) return ;
$max_index = count($datas) - 1;
/* Process all nodes in this layer */
foreach ( $datas as $i => $data ) {
             /* Whether the current node and all ancestors are marked as tail nodes */
$tmp_is_last = $is_last << 1 | 1 & $i == $max_index;
/* Output the current node */
Node_out($string, $data, $level, $i, $tmp_is_last);
           /* If there are child nodes, recurse the child nodes */
If ( is_array($data[K_CHILD]) && !emptyempty($data[K_CHILD]) )
Tree_parse($string, $data[K_CHILD], $level + 1, $tmp_is_last);
}  
}

/* Calculate the actual number of nodes */
function n_node($n, $s) {
$sum = 0;
while ( $n > 0 )
$sum += pow($s, $n --);
Return $sum;
}
/* Calculate ruage time */
function ru_time($info, $type) {
Return floatval(sprintf('%d.%d', $info[$type . '.tv_sec'], $info[$type . '.tv_usec']));
}
/* Output resource usage */
function resource_usage($lv, $nodes, $cb, $ce, $mb, $me, $rb, $re) {
Printf("nresource usage[level: %d, node number: %d]: n%20s%0.6fsn%20s%0.6fsn%20s%0.6fsn%20s%d byten",
         $lv, $nodes,
'clock time: ', $ce - $cb,
        'system cpu: ',      ru_time($re, 'ru_stime') - ru_time($rb, 'ru_stime'), 
        'user cpu: ',       ru_time($re, 'ru_utime') - ru_time($rb, 'ru_utime'), 
'memory usage: ', $me - $mb);
}
/* Usage */
function usage($cmd) {
Printf("usage: n%s n", $cmd);
exit;
}

/* Test entry function */
function run() {
global $argc, $argv;

If ( $argc != 2 || intval($argv[1]) < 1 )
usage($argv[0]);


$datas = array();
$id = 1;
$string = '';
$level = intval($argv[1]);

/* Initial construction of test tree */
Tree_build($datas, $id, $level);

$clock_begin = microtime(TRUE);
$memory_begin = memory_get_usage();
$rusage_begin = getrusage();
/* Parse tree */
Tree_parse($string, $datas);
$rusage_end = getrusage();
$memory_end = memory_get_usage();
$clock_end = microtime(TRUE);

/* Output results */
echo $string . "n";

Resource_usage($level, n_node($level, MAX_NODES),
$clock_begin, $clock_end,
         $memory_begin, $memory_end, 
         $rusage_begin, $rusage_end);
}

/* Execute entry function */
run();
/*
* Local variables:
* tab-width: 4
* c-basic-offset: 4
* indent-tabs-mode: t
* End:
*/