Discuz!常用函数解析（1）

转载自：http://www.discuz.net/thread-1582651-1-1.html

 

<?php

/*
        [Discuz!] (C)2001-2007 Comsenz Inc.
        This is NOT a freeware, use is subject to license terms

        $Id: global.func.php 13426 2008-04-15 03:37:02Z heyond $
*/

if(!defined('IN_DISCUZ')) {
        exit('Access Denied');
}

/**
* 加密或者解密用户信息
* @param $string - 加密或解密的串
* @param $operation - 加密还是解密
* @param 密钥
* @return 返回字符串
* $ckey_length 随机密钥长度 取值 0-32;
* 加入随机密钥，可以令密文无任何规律，即便是原文和密钥完全相同，加密结果也会每次不同，增大破解难度。
* 取值越大，密文变动规律越大，密文变化 = 16 的 $ckey_length 次方
* 当此值为 0 时，则不产生随机密钥
*/

function authcode($string, $operation = 'DECODE', $key = '', $expiry = 0) {

        $ckey_length = 4;
        $key = md5($key ? $key : $GLOBALS['discuz_auth_key']);
        $keya = md5(substr($key, 0, 16));
        $keyb = md5(substr($key, 16, 16));
        $keyc = $ckey_length ? ($operation == 'DECODE' ? substr($string, 0, $ckey_length): substr(md5(microtime()), -$ckey_length)) : '';

        $cryptkey = $keya.md5($keya.$keyc);
        $key_length = strlen($cryptkey);

        $string = $operation == 'DECODE' ? base64_decode(substr($string, $ckey_length)) : sprintf('%010d', $expiry ? $expiry + time() : 0).substr(md5($string.$keyb), 0, 16).$string;
        $string_length = strlen($string);

        $result = '';
        $box = range(0, 255);

        $rndkey = array();
        for($i = 0; $i <= 255; $i++) {
                $rndkey[$i] = ord($cryptkey[$i % $key_length]);
        }

        for($j = $i = 0; $i < 256; $i++) {
                $j = ($j + $box[$i] + $rndkey[$i]) % 256;
                $tmp = $box[$i];
                $box[$i] = $box[$j];
                $box[$j] = $tmp;
        }

        for($a = $j = $i = 0; $i < $string_length; $i++) {
                $a = ($a + 1) % 256;
                $j = ($j + $box[$a]) % 256;
                $tmp = $box[$a];
                $box[$a] = $box[$j];
                $box[$j] = $tmp;
                $result .= chr(ord($string[$i]) ^ ($box[($box[$a] + $box[$j]) % 256]));
        }

        if($operation == 'DECODE') {
                if((substr($result, 0, 10) == 0 || substr($result, 0, 10) - time() > 0) && substr($result, 10, 16) == substr(md5(substr($result, 26).$keyb), 0, 16)) {
                        return substr($result, 26);
                } else {
                        return '';
                }
        } else {
                return $keyc.str_replace('=', '', base64_encode($result));
        }

}

/**
* 清理cookie
*/
function clearcookies() {
        global $discuz_uid, $discuz_user, $discuz_pw, $discuz_secques, $adminid, $credits;
        dsetcookie('sid', '', -86400 * 365);
        dsetcookie('auth', '', -86400 * 365);
        dsetcookie('visitedfid', '', -86400 * 365);
        dsetcookie('onlinedetail', '', -86400 * 365, 0);
        dsetcookie('loginuser', '', -86400 * 365);
        dsetcookie('activationauth', '', -86400 * 365);

        $discuz_uid = $adminid = $credits = 0;
        $discuz_user = $discuz_pw = $discuz_secques = '';
}

/**
* 检查积分下限
* @param $creditsarray - 积分数组
* @param $coef - 积分
*/
function checklowerlimit($creditsarray, $coef = 1) {
        if(is_array($creditsarray)) {
                global $extcredits, $id;
                foreach($creditsarray as $id => $addcredits) {
                        $addcredits = $addcredits * $coef;
                        if($addcredits < 0 && ($GLOBALS['extcredits'.$id] < $extcredits[$id]['lowerlimit'] || (($GLOBALS['extcredits'.$id] + $addcredits) < $extcredits[$id]['lowerlimit']))) {
                                if($coef == 1) {
                                        showmessage('credits_policy_lowerlimit');
                                } else {
                                        showmessage('credits_policy_num_lowerlimit');
                                }
                        }
                }
        }
}

/**
* 密码检测
*
* @param string $md5
* @param string $verified
* @param string $salt
* @return
*         0= Failed
*         1= MD5 with salt, 2= Dual MD5, 3= Normal Md5 4= MD5-16
*/

function checkmd5($md5, $verified, $salt = '') {
        if(md5($md5.$salt) == $verified) {
                $result = !empty($salt) ? 1 : 2;
        } elseif(empty($salt)) {
                $result = $md5 == $verified ? 3 : ((strlen($verified) == 16 && substr($md5, 8, 16) == $verified) ? 4 : 0);
        } else {
                $result = 0;
        }
        return $result;
}

/**
* 检查模板源文件是否更新
* 当编译文件不存时强制重新编译
* 当 tplrefresh = 1 时检查文件
* 当 tplrefresh > 1 时，则根据 tplrefresh 取余，无余时则检查更新
*
*/
function checktplrefresh($maintpl, $subtpl, $timecompare, $templateid, $tpldir) {
        global $tplrefresh;
        if(empty($timecompare) || $tplrefresh == 1 || ($tplrefresh > 1 && !($GLOBALS['timestamp'] % $tplrefresh))) {
                if(empty($timecompare) || @filemtime($subtpl) > $timecompare) {
                        require_once DISCUZ_ROOT.'./include/template.func.php';
                        parse_template($maintpl, $templateid, $tpldir);
                        return TRUE;
                }
        }
        return         FALSE;
}
?>