function dr_url($url, $query = [], $self = SELF) {

return \Phpcmf\Service::L('router')->url($url, $query, $self);

}

function dr_furl($name) {

return \Phpcmf\Service::L('router')->furl($name);

}

function dr_get_tag_url($name, $mid = '') {

return \Phpcmf\Service::L('router')->get_tag_url($name, $mid);

}

function dr_comment_url($id, $moddir = '') {

return \Phpcmf\Service::L('router')->comment_url($id, $moddir);

}

function dr_form_show_url($table, $id, $page = 0) {

return \Phpcmf\Service::L('router')->form_show_url($table, $id, $page);

}

function dr_oauth_url($name, $type, $gourl = '') {

return \Phpcmf\Service::L('router')->oauth_url($name, $type, $gourl);

}

function dr_member_url($url, $query = [], $self = 'index.php') {

return \Phpcmf\Service::L('router')->member_url($url, $query, $self);

}

function dr_search_url($params = [], $name = '', $value = '', $moddir = '') {

return \Phpcmf\Service::L('router')->search_url($params, $name, $value, $moddir);

}

    private function updateBatchSql($table, $data, $key) {
        if (empty($data)) {
            throw new Exception('data format is error');
        }
        $ids = array_column($data, $key);
        $_ids = implode("','", $ids);
        $cols = array_keys($data[0]);
        $sql = "UPDATE {$table} SET %s WHERE `{$key}` IN ('{$_ids}')";
        $update = [];
        foreach ($cols as $v) {
            if ($v == $key) continue;
            $_str = "`{$v}`= ( CASE `{$key}` %s ELSE `{$v}` END)";
            $_when = [];
            foreach ($data as $row) {
                $_when[] = "WHEN '{$row[$key]}' THEN '{$row[$v]}'";
            }
            $_str = sprintf($_str, implode(' ', $_when));
            $update[] = $_str;
        }
        $sql = sprintf($sql, implode(', ', $update));
        return $sql;
    }

https://fedoraproject.org/wiki/EPEL

达到的结果：

count: 5, level: 3
0_1_2
0_1_3
0_1_4
0_2_3
0_2_4
0_3_4
1_2_3
1_2_4
1_3_4
2_3_4

function actionTest($count, $level) {
        echo "count: {$count}, level: {$level}\n";
        foreach (new arrangeIterator($count, $level) as $k=>$v) {
            echo "{$k}\n";
        }
    }


class arrangeIterator implements Iterator {

    private $count, $level;
    private $idxArr = [];

    public function __construct($count, $level) {
        $this->count = $count;
        $this->level = $level;
        $this->idxArr = range(0, $this->level-1);
    }

    /**
     * Return the current element
     * @link  https://php.net/manual/en/iterator.current.php
     * @return mixed Can return any type.
     * @since 5.0.0
     */
    public function current() {
        // TODO: Implement current() method.
        return $this->idxArr;
    }

    /**
     * Move forward to next element
     * @link  https://php.net/manual/en/iterator.next.php
     * @return void Any returned value is ignored.
     * @since 5.0.0
     */
    public function next() {
        // TODO: Implement next() method.
        $i = $this->level-1; //最大下标
        $n = 1;
        $idx = $i;
        while($i>=0) {
            if ($this->idxArr[$i] + 1 > $this->count-$n) {
                $i--;
                $n++;
                continue;
            }
            $idx = $i;
            break;
        }
        $tmp = $this->idxArr[$idx];
        $step = 1;
        for($i=$idx; $i<$this->level; $i++) {
            $this->idxArr[$i]=$tmp+$step;
            $step++;
        }

    }

    /**
     * Return the key of the current element
     * @link  https://php.net/manual/en/iterator.key.php
     * @return mixed scalar on success, or null on failure.
     * @since 5.0.0
     */
    public function key() {
        // TODO: Implement key() method.
        return implode('_', $this->idxArr);
    }

    /**
     * Checks if current position is valid
     * @link  https://php.net/manual/en/iterator.valid.php
     * @return bool The return value will be casted to boolean and then evaluated.
     * Returns true on success or false on failure.
     * @since 5.0.0
     */
    public function valid() {
        // TODO: Implement valid() method.
        return $this->level>0 && $this->idxArr[0] <= $this->count - $this->level && $this->idxArr[$this->level-1] <= $this->count - 1;
    }

    /**
     * Rewind the Iterator to the first element
     * @link  https://php.net/manual/en/iterator.rewind.php
     * @return void Any returned value is ignored.
     * @since 5.0.0
     */
    public function rewind() {
        // TODO: Implement rewind() method.
        $this->idxArr = range(0, $this->level-1);
    }
}

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