php discuz@功能的代码

$atlist = $atlist_tmp = $ateduids = array();
        preg_match_all("/@([^\\r\\n]*?)\\s/i", $message.' ', $atlist_tmp);//解析内容里的被@到的名字。
        $atlist_tmp = array_slice(array_unique($atlist_tmp[1]), 0, $_G['group']['allowat']);//应该是提取用户名吧。。
        $atnum = $maxselect = 0;
        foreach(C::t('home_notification')->fetch_all_by_authorid_fromid($_G['uid'], $_G['tid'], 'at') as $row) {
            $atnum ++;//这个循环暂时搞不懂。还没看过这个表是干嘛的。
            $ateduids[$row[uid]] = $row['uid'];
        }
        $maxselect = $_G['group']['allowat'] - $atnum;
        if($maxselect > 0 && !empty($atlist_tmp)) {
        if(empty($_G['setting']['at_anyone'])) {//判断是否只能@好友，如果只能@好友的话，那就从下面的home_follow表中找出在好友列表里的人的姓名。其他的就@不到了。
                foreach(C::t('home_follow')->fetch_all_by_uid_fusername($_G['uid'], $atlist_tmp) as $row) {
                    if(!in_array($row['followuid'], $ateduids)) {
                        $atlist[$row[followuid]] = $row['fusername'];
                    }
                    if(count($atlist) == $maxselect) {
                        break;
                    }
                }
                if(count($atlist) < $maxselect) {//判断@上限。
                    $query = C::t('home_friend')->fetch_all_by_uid_username($_G['uid'], $atlist_tmp);//不用说了吧
                    foreach($query as $row) {
                        if(!in_array($row['followuid'], $ateduids)) {
                            $atlist[$row[fuid]] = $row['fusername'];
                        }
                    }
                }
            } else {
                foreach(C::t('common_member')->fetch_all_by_username($atlist_tmp) as $row) {
                    if(in_array($row['uid'], $ateduids)) {
                        $atlist[$row[uid]] = $row['username'];
                    }
                    if(count($atlist) == $maxselect) {
                        break;
                    }
                }
            }
        }
        if($atlist) {//提醒和加链接。
            foreach($atlist as $atuid => $atusername) {
                $notic = array('subject' => '测试主题', 'message' => '测试内容 来自代码片段outofmemory.cn 'from_id' => 0, 'from_idtype' => 'sendnotice');
                notification_add($atuid,'system','system_notice',$notic,1);//发送提醒给被@到的用户。$notic是提醒的内容。
                $atsearch[] = "/@$atusername /i";
                $atreplace[] = "[url=home.php?mod=space&uid=$atuid]@{$atusername}[/url] ";//加链接，但不是a标签。
            }
            $message = preg_replace($atsearch, $atreplace, $message.' ', 1);
        }
require_once libfile('function/followcode');
require_once libfile('function/discuzcode'); 
$cont=followcode($message);//格式化代码中的标签
//该片段来自于http://outofmemory.cn