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<?php

/**

*

* @package phpBB3

* @version $Id$

* @copyright (c) 2005 phpBB Group

* @license http://opensource.org/licenses/gpl-license.php GNU Public License

*

*/

/**

* @ignore

*/

if (!defined('IN_PHPBB'))

{

        exit;

}

/**

* Permission/Auth class

* @package phpBB3

*/

class auth

{

        var $acl = array();

        var $cache = array();

        var $acl_options = array();

        var $acl_forum_ids = false;

        /**

        * Init permissions

        */

        function acl(&$userdata)

        {

                global $db, $cache;

                $this->acl = $this->cache = $this->acl_options = array();

                $this->acl_forum_ids = false;

                if (($this->acl_options = $cache->get('_acl_options')) === false)

                {

                        $sql = 'SELECT auth_option_id, auth_option, is_global, is_local

                                FROM ' . ACL_OPTIONS_TABLE . '

                                ORDER BY auth_option_id';

                        $result = $db->sql_query($sql);

                        $global = $local = 0;

                        $this->acl_options = array();

                        while ($row = $db->sql_fetchrow($result))

                        {

                                if ($row['is_global'])

                                {

                                        $this->acl_options['global'][$row['auth_option']] = $global++;

                                }

                                if ($row['is_local'])

                                {

                                        $this->acl_options['local'][$row['auth_option']] = $local++;

                                }

                                $this->acl_options['id'][$row['auth_option']] = (int) $row['auth_option_id'];

                                $this->acl_options['option'][(int) $row['auth_option_id']] = $row['auth_option'];

                        }

                        $db->sql_freeresult($result);

                        $cache->put('_acl_options', $this->acl_options);

                }

                if (!trim($userdata['user_permissions']))

                {

                        $this->acl_cache($userdata);

                }

                // Fill ACL array

                $this->_fill_acl($userdata['user_permissions']);

                // Verify bitstring length with options provided...

                $renew = false;

                $global_length = sizeof($this->acl_options['global']);

                $local_length = sizeof($this->acl_options['local']);

                // Specify comparing length (bitstring is padded to 31 bits)

                $global_length = ($global_length % 31) ? ($global_length - ($global_length % 31) + 31) : $global_length;

                $local_length = ($local_length % 31) ? ($local_length - ($local_length % 31) + 31) : $local_length;

                // You thought we are finished now? Noooo... now compare them.

                foreach ($this->acl as $forum_id => $bitstring)

                {

                        if (($forum_id && strlen($bitstring) != $local_length) || (!$forum_id && strlen($bitstring) != $global_length))

                        {

                                $renew = true;

                                break;

                        }

                }

                // If a bitstring within the list does not match the options, we have a user with incorrect permissions set and need to renew them

                if ($renew)

                {

                        $this->acl_cache($userdata);

                        $this->_fill_acl($userdata['user_permissions']);

                }

                return;

        }

        /**

        * Fill ACL array with relevant bitstrings from user_permissions column

        * @access private

        */

        function _fill_acl($user_permissions)

        {

                $seq_cache = array();

                $this->acl = array();

                $user_permissions = explode("\n", $user_permissions);

                foreach ($user_permissions as $f => $seq)

                {

                        if ($seq)

                        {

                                $i = 0;

                                if (!isset($this->acl[$f]))

                                {

                                        $this->acl[$f] = '';

                                }

                                while ($subseq = substr($seq, $i, 6))

                                {

                                        if (isset($seq_cache[$subseq]))

                                        {

                                                $converted = $seq_cache[$subseq];

                                        }

                                        else

                                        {

                                                $converted = $seq_cache[$subseq] = str_pad(base_convert($subseq, 36, 2), 31, 0, STR_PAD_LEFT);

                                        }

                                        // We put the original bitstring into the acl array

                                        $this->acl[$f] .= $converted;

                                        $i += 6;

                                }

                        }

                }

        }

        /**

        * Look up an option

        * if the option is prefixed with !, then the result becomes negated

        *

        * If a forum id is specified the local option will be combined with a global option if one exist.

        * If a forum id is not specified, only the global option will be checked.

        */

        function acl_get($opt, $f = 0)

        {

                $negate = false;

                if (strpos($opt, '!') === 0)

                {

                        $negate = true;

                        $opt = substr($opt, 1);

                }

                if (!isset($this->cache[$f][$opt]))

                {

                        // We combine the global/local option with an OR because some options are global and local.

                        // If the user has the global permission the local one is true too and vice versa

                        $this->cache[$f][$opt] = false;

                        // Is this option a global permission setting?

                        if (isset($this->acl_options['global'][$opt]))

                        {

                                if (isset($this->acl[0]))

                                {

                                        $this->cache[$f][$opt] = $this->acl[0][$this->acl_options['global'][$opt]];

                                }

                        }

                        // Is this option a local permission setting?

                        // But if we check for a global option only, we won't combine the options...

                        if ($f != 0 && isset($this->acl_options['local'][$opt]))

                        {

                                if (isset($this->acl[$f]) && isset($this->acl[$f][$this->acl_options['local'][$opt]]))

                                {

                                        $this->cache[$f][$opt] |= $this->acl[$f][$this->acl_options['local'][$opt]];

                                }

                        }

                }

                // Founder always has all global options set to true...

                return ($negate) ? !$this->cache[$f][$opt] : $this->cache[$f][$opt];

        }

        /**

        * Get forums with the specified permission setting

        * if the option is prefixed with !, then the result becomes nagated

        *

        * @param bool $clean set to true if only values needs to be returned which are set/unset

        */

        function acl_getf($opt, $clean = false)

        {

                $acl_f = array();

                $negate = false;

                if (strpos($opt, '!') === 0)

                {

                        $negate = true;

                        $opt = substr($opt, 1);

                }

                // If we retrieve a list of forums not having permissions in, we need to get every forum_id

                if ($negate)

                {

                        if ($this->acl_forum_ids === false)

                        {

                                global $db;

                                $sql = 'SELECT forum_id

                                        FROM ' . FORUMS_TABLE;

                                if (sizeof($this->acl))

                                {

                                        $sql .= ' WHERE ' . $db->sql_in_set('forum_id', array_keys($this->acl), true);

                                }

                                $result = $db->sql_query($sql);

                                $this->acl_forum_ids = array();

                                while ($row = $db->sql_fetchrow($result))

                                {

                                        $this->acl_forum_ids[] = $row['forum_id'];

                                }

                                $db->sql_freeresult($result);

                        }

                }

                if (isset($this->acl_options['local'][$opt]))

                {

                        foreach ($this->acl as $f => $bitstring)

                        {

                                // Skip global settings

                                if (!$f)

                                {

                                        continue;

                                }

                                $allowed = (!isset($this->cache[$f][$opt])) ? $this->acl_get($opt, $f) : $this->cache[$f][$opt];

                                if (!$clean)

                                {

                                        $acl_f[$f][$opt] = ($negate) ? !$allowed : $allowed;

                                }

                                else

                                {

                                        if (($negate && !$allowed) || (!$negate && $allowed))

                                        {

                                                $acl_f[$f][$opt] = 1;

                                        }

                                }

                        }

                }

                // If we get forum_ids not having this permission, we need to fill the remaining parts

                if ($negate && sizeof($this->acl_forum_ids))

                {

                        foreach ($this->acl_forum_ids as $f)

                        {

                                $acl_f[$f][$opt] = 1;

                        }

                }

                return $acl_f;

        }

        /**

        * Get local permission state for any forum.

        *

        * Returns true if user has the permission in one or more forums, false if in no forum.

        * If global option is checked it returns the global state (same as acl_get($opt))

        * Local option has precedence...

        */

        function acl_getf_global($opt)

        {

                if (is_array($opt))

                {

                        // evaluates to true as soon as acl_getf_global is true for one option

                        foreach ($opt as $check_option)

                        {

                                if ($this->acl_getf_global($check_option))

                                {

                                        return true;

                                }

                        }

                        return false;

                }

                if (isset($this->acl_options['local'][$opt]))

                {

                        foreach ($this->acl as $f => $bitstring)

                        {

                                // Skip global settings

                                if (!$f)

                                {

                                        continue;

                                }

                                // as soon as the user has any permission we're done so return true

                                if ((!isset($this->cache[$f][$opt])) ? $this->acl_get($opt, $f) : $this->cache[$f][$opt])

                                {

                                        return true;

                                }

                        }

                }

                else if (isset($this->acl_options['global'][$opt]))

                {

                        return $this->acl_get($opt);

                }

                return false;

        }

        /**

        * Get permission settings (more than one)

        */

        function acl_gets()

        {

                $args = func_get_args();

                $f = array_pop($args);

                if (!is_numeric($f))

                {

                        $args[] = $f;

                        $f = 0;

                }

                // alternate syntax: acl_gets(array('m_', 'a_'), $forum_id)

                if (is_array($args[0]))

                {

                        $args = $args[0];

                }

                $acl = 0;

                foreach ($args as $opt)

                {

                        $acl |= $this->acl_get($opt, $f);

                }

                return $acl;

        }

        /**

        * Get permission listing based on user_id/options/forum_ids

        *

        * Be careful when using this function with permissions a_, m_, u_ and f_ !

        * It may not work correctly. When a user group grants an a_* permission,

        * e.g. a_foo, but the user's a_foo permission is set to "Never", then

        * the user does not in fact have the a_ permission.

        * But the user will still be listed as having the a_ permission.

        *

        * For more information see: http://tracker.phpbb.com/browse/PHPBB3-10252

        */

        function acl_get_list($user_id = false, $opts = false, $forum_id = false)

        {

                if ($user_id !== false && !is_array($user_id) && $opts === false && $forum_id === false)

                {

                        $hold_ary = array($user_id => $this->acl_raw_data_single_user($user_id));

                }

                else

                {

                        $hold_ary = $this->acl_raw_data($user_id, $opts, $forum_id);

                }

                $auth_ary = array();

                foreach ($hold_ary as $user_id => $forum_ary)

                {

                        foreach ($forum_ary as $forum_id => $auth_option_ary)

                        {

                                foreach ($auth_option_ary as $auth_option => $auth_setting)

                                {

                                        if ($auth_setting)

                                        {

                                                $auth_ary[$forum_id][$auth_option][] = $user_id;

                                        }

                                }

                        }

                }

                return $auth_ary;

        }

        /**

        * Cache data to user_permissions row

        */

        function acl_cache(&$userdata)

        {

                global $db;

                // Empty user_permissions

                $userdata['user_permissions'] = '';

                $hold_ary = $this->acl_raw_data_single_user($userdata['user_id']);

                // Key 0 in $hold_ary are global options, all others are forum_ids

                // If this user is founder we're going to force fill the admin options ...

                if ($userdata['user_type'] == USER_FOUNDER)

                {

                        foreach ($this->acl_options['global'] as $opt => $id)

                        {

                                if (strpos($opt, 'a_') === 0)

                                {

                                        $hold_ary[0][$this->acl_options['id'][$opt]] = ACL_YES;

                                }

                        }

                }

                $hold_str = $this->build_bitstring($hold_ary);

                if ($hold_str)

                {

                        $userdata['user_permissions'] = $hold_str;

                        $sql = 'UPDATE ' . USERS_TABLE . "

                                SET user_permissions = '" . $db->sql_escape($userdata['user_permissions']) . "',

                                        user_perm_from = 0

                                WHERE user_id = " . $userdata['user_id'];

                        $db->sql_query($sql);

                }

                return;

        }

        /**

        * Build bitstring from permission set

        */

        function build_bitstring(&$hold_ary)

        {

                $hold_str = '';

                if (sizeof($hold_ary))

                {

                        ksort($hold_ary);

                        $last_f = 0;

                        foreach ($hold_ary as $f => $auth_ary)

                        {

                                $ary_key = (!$f) ? 'global' : 'local';

                                $bitstring = array();

                                foreach ($this->acl_options[$ary_key] as $opt => $id)

                                {

                                        if (isset($auth_ary[$this->acl_options['id'][$opt]]))

                                        {

                                                $bitstring[$id] = $auth_ary[$this->acl_options['id'][$opt]];

                                                $option_key = substr($opt, 0, strpos($opt, '_') + 1);

                                                // If one option is allowed, the global permission for this option has to be allowed too

                                                // example: if the user has the a_ permission this means he has one or more a_* permissions

                                                if ($auth_ary[$this->acl_options['id'][$opt]] == ACL_YES && (!isset($bitstring[$this->acl_options[$ary_key][$option_key]]) || $bitstring[$this->acl_options[$ary_key][$option_key]] == ACL_NEVER))

                                                {

                                                        $bitstring[$this->acl_options[$ary_key][$option_key]] = ACL_YES;

                                                }

                                        }

                                        else

                                        {

                                                $bitstring[$id] = ACL_NEVER;

                                        }

                                }

                                // Now this bitstring defines the permission setting for the current forum $f (or global setting)

                                $bitstring = implode('', $bitstring);

                                // The line number indicates the id, therefore we have to add empty lines for those ids not present

                                $hold_str .= str_repeat("\n", $f - $last_f);

                                // Convert bitstring for storage - we do not use binary/bytes because PHP's string functions are not fully binary safe

                                for ($i = 0, $bit_length = strlen($bitstring); $i < $bit_length; $i += 31)

                                {

                                        $hold_str .= str_pad(base_convert(str_pad(substr($bitstring, $i, 31), 31, 0, STR_PAD_RIGHT), 2, 36), 6, 0, STR_PAD_LEFT);

                                }

                                $last_f = $f;

                        }

                        unset($bitstring);

                        $hold_str = rtrim($hold_str);

                }

                return $hold_str;

        }

        /**

        * Clear one or all users cached permission settings

        */

        function acl_clear_prefetch($user_id = false)

        {

                global $db, $cache;

                // Rebuild options cache

                $cache->destroy('_role_cache');

                $sql = 'SELECT *

                        FROM ' . ACL_ROLES_DATA_TABLE . '

                        ORDER BY role_id ASC';

                $result = $db->sql_query($sql);

                $this->role_cache = array();

                while ($row = $db->sql_fetchrow($result))

                {

                        $this->role_cache[$row['role_id']][$row['auth_option_id']] = (int) $row['auth_setting'];

                }

                $db->sql_freeresult($result);

                foreach ($this->role_cache as $role_id => $role_options)

                {

                        $this->role_cache[$role_id] = serialize($role_options);

                }

                $cache->put('_role_cache', $this->role_cache);

                // Now empty user permissions

                $where_sql = '';

                if ($user_id !== false)

                {

                        $user_id = (!is_array($user_id)) ? $user_id = array((int) $user_id) : array_map('intval', $user_id);

                        $where_sql = ' WHERE ' . $db->sql_in_set('user_id', $user_id);

                }

                $sql = 'UPDATE ' . USERS_TABLE . "

                        SET user_permissions = '',

                                user_perm_from = 0

                        $where_sql";

                $db->sql_query($sql);

                return;

        }

        /**

        * Get assigned roles

        */

        function acl_role_data($user_type, $role_type, $ug_id = false, $forum_id = false)

        {

                global $db;

                $roles = array();

                $sql_id = ($user_type == 'user') ? 'user_id' : 'group_id';

                $sql_ug = ($ug_id !== false) ? ((!is_array($ug_id)) ? "AND a.$sql_id = $ug_id" : 'AND ' . $db->sql_in_set("a.$sql_id", $ug_id)) : '';

                $sql_forum = ($forum_id !== false) ? ((!is_array($forum_id)) ? "AND a.forum_id = $forum_id" : 'AND ' . $db->sql_in_set('a.forum_id', $forum_id)) : '';

                // Grab assigned roles...

                $sql = 'SELECT a.auth_role_id, a.' . $sql_id . ', a.forum_id

                        FROM ' . (($user_type == 'user') ? ACL_USERS_TABLE : ACL_GROUPS_TABLE) . ' a, ' . ACL_ROLES_TABLE . " r

                        WHERE a.auth_role_id = r.role_id

                                AND r.role_type = '" . $db->sql_escape($role_type) . "'

                                $sql_ug

                                $sql_forum

                        ORDER BY r.role_order ASC";

                $result = $db->sql_query($sql);

                while ($row = $db->sql_fetchrow($result))

                {

                        $roles[$row[$sql_id]][$row['forum_id']] = $row['auth_role_id'];

                }

                $db->sql_freeresult($result);

                return $roles;

        }

        /**

        * Get raw acl data based on user/option/forum

        */

        function acl_raw_data($user_id = false, $opts = false, $forum_id = false)

        {

                global $db;

                $sql_user = ($user_id !== false) ? ((!is_array($user_id)) ? 'user_id = ' . (int) $user_id : $db->sql_in_set('user_id', array_map('intval', $user_id))) : '';

                $sql_forum = ($forum_id !== false) ? ((!is_array($forum_id)) ? 'AND a.forum_id = ' . (int) $forum_id : 'AND ' . $db->sql_in_set('a.forum_id', array_map('intval', $forum_id))) : '';

                $sql_opts = $sql_opts_select = $sql_opts_from = '';

                $hold_ary = array();

                if ($opts !== false)

                {

                        $sql_opts_select = ', ao.auth_option';

                        $sql_opts_from = ', ' . ACL_OPTIONS_TABLE . ' ao';

                        $this->build_auth_option_statement('ao.auth_option', $opts, $sql_opts);

                }

                $sql_ary = array();

                // Grab non-role settings - user-specific

                $sql_ary[] = 'SELECT a.user_id, a.forum_id, a.auth_setting, a.auth_option_id' . $sql_opts_select . '

                        FROM ' . ACL_USERS_TABLE . ' a' . $sql_opts_from . '

                        WHERE a.auth_role_id = 0 ' .

                                (($sql_opts_from) ? 'AND a.auth_option_id = ao.auth_option_id ' : '') .

                                (($sql_user) ? 'AND a.' . $sql_user : '') . "

                                $sql_forum

                                $sql_opts";

                // Now the role settings - user-specific

                $sql_ary[] = 'SELECT a.user_id, a.forum_id, r.auth_option_id, r.auth_setting, r.auth_option_id' . $sql_opts_select . '

                        FROM ' . ACL_USERS_TABLE . ' a, ' . ACL_ROLES_DATA_TABLE . ' r' . $sql_opts_from . '

                        WHERE a.auth_role_id = r.role_id ' .

                                (($sql_opts_from) ? 'AND r.auth_option_id = ao.auth_option_id ' : '') .

                                (($sql_user) ? 'AND a.' . $sql_user : '') . "

                                $sql_forum

                                $sql_opts";

                foreach ($sql_ary as $sql)

                {

                        $result = $db->sql_query($sql);

                        while ($row = $db->sql_fetchrow($result))

                        {

                                $option = ($sql_opts_select) ? $row['auth_option'] : $this->acl_options['option'][$row['auth_option_id']];

                                $hold_ary[$row['user_id']][$row['forum_id']][$option] = $row['auth_setting'];

                        }

                        $db->sql_freeresult($result);

                }

                $sql_ary = array();

                // Now grab group settings - non-role specific...

                $sql_ary[] = 'SELECT ug.user_id, a.forum_id, a.auth_setting, a.auth_option_id' . $sql_opts_select . '

                        FROM ' . ACL_GROUPS_TABLE . ' a, ' . USER_GROUP_TABLE . ' ug, ' . GROUPS_TABLE . ' g' . $sql_opts_from . '

                        WHERE a.auth_role_id = 0 ' .

                                (($sql_opts_from) ? 'AND a.auth_option_id = ao.auth_option_id ' : '') . '

                                AND a.group_id = ug.group_id

                                AND g.group_id = ug.group_id

                                AND ug.user_pending = 0

                                AND NOT (ug.group_leader = 1 AND g.group_skip_auth = 1)

                                ' . (($sql_user) ? 'AND ug.' . $sql_user : '') . "

                                $sql_forum

                                $sql_opts";

                // Now grab group settings - role specific...

                $sql_ary[] = 'SELECT ug.user_id, a.forum_id, r.auth_setting, r.auth_option_id' . $sql_opts_select . '

                        FROM ' . ACL_GROUPS_TABLE . ' a, ' . USER_GROUP_TABLE . ' ug, ' . GROUPS_TABLE . ' g, ' . ACL_ROLES_DATA_TABLE . ' r' . $sql_opts_from . '

                        WHERE a.auth_role_id = r.role_id ' .

                                (($sql_opts_from) ? 'AND r.auth_option_id = ao.auth_option_id ' : '') . '

                                AND a.group_id = ug.group_id

                                AND g.group_id = ug.group_id

                                AND ug.user_pending = 0

                                AND NOT (ug.group_leader = 1 AND g.group_skip_auth = 1)

                                ' . (($sql_user) ? 'AND ug.' . $sql_user : '') . "

                                $sql_forum

                                $sql_opts";

                foreach ($sql_ary as $sql)

                {

                        $result = $db->sql_query($sql);

                        while ($row = $db->sql_fetchrow($result))

                        {

                                $option = ($sql_opts_select) ? $row['auth_option'] : $this->acl_options['option'][$row['auth_option_id']];

                                if (!isset($hold_ary[$row['user_id']][$row['forum_id']][$option]) || (isset($hold_ary[$row['user_id']][$row['forum_id']][$option]) && $hold_ary[$row['user_id']][$row['forum_id']][$option] != ACL_NEVER))

                                {

                                        $hold_ary[$row['user_id']][$row['forum_id']][$option] = $row['auth_setting'];

                                        // If we detect ACL_NEVER, we will unset the flag option (within building the bitstring it is correctly set again)

                                        if ($row['auth_setting'] == ACL_NEVER)

                                        {

                                                $flag = substr($option, 0, strpos($option, '_') + 1);

                                                if (isset($hold_ary[$row['user_id']][$row['forum_id']][$flag]) && $hold_ary[$row['user_id']][$row['forum_id']][$flag] == ACL_YES)

                                                {

                                                        unset($hold_ary[$row['user_id']][$row['forum_id']][$flag]);

/*                                                        if (in_array(ACL_YES, $hold_ary[$row['user_id']][$row['forum_id']]))

                                                        {

                                                                $hold_ary[$row['user_id']][$row['forum_id']][$flag] = ACL_YES;

                                                        }

*/

                                                }

                                        }

                                }

                        }

                        $db->sql_freeresult($result);

                }

                return $hold_ary;

        }

        /**

        * Get raw user based permission settings

        */

        function acl_user_raw_data($user_id = false, $opts = false, $forum_id = false)

        {

                global $db;

                $sql_user = ($user_id !== false) ? ((!is_array($user_id)) ? 'user_id = ' . (int) $user_id : $db->sql_in_set('user_id', array_map('intval', $user_id))) : '';

                $sql_forum = ($forum_id !== false) ? ((!is_array($forum_id)) ? 'AND a.forum_id = ' . (int) $forum_id : 'AND ' . $db->sql_in_set('a.forum_id', array_map('intval', $forum_id))) : '';

                $sql_opts = '';

                $hold_ary = $sql_ary = array();

                if ($opts !== false)

                {

                        $this->build_auth_option_statement('ao.auth_option', $opts, $sql_opts);

                }

                // Grab user settings - non-role specific...

                $sql_ary[] = 'SELECT a.user_id, a.forum_id, a.auth_setting, a.auth_option_id, ao.auth_option

                        FROM ' . ACL_USERS_TABLE . ' a, ' . ACL_OPTIONS_TABLE . ' ao

                        WHERE a.auth_role_id = 0

                                AND a.auth_option_id = ao.auth_option_id ' .

                                (($sql_user) ? 'AND a.' . $sql_user : '') . "

                                $sql_forum

                                $sql_opts

                        ORDER BY a.forum_id, ao.auth_option";

                // Now the role settings - user-specific

                $sql_ary[] = 'SELECT a.user_id, a.forum_id, r.auth_option_id, r.auth_setting, r.auth_option_id, ao.auth_option

                        FROM ' . ACL_USERS_TABLE . ' a, ' . ACL_ROLES_DATA_TABLE . ' r, ' . ACL_OPTIONS_TABLE . ' ao

                        WHERE a.auth_role_id = r.role_id

                                AND r.auth_option_id = ao.auth_option_id ' .

                                (($sql_user) ? 'AND a.' . $sql_user : '') . "

                                $sql_forum

                                $sql_opts

                        ORDER BY a.forum_id, ao.auth_option";

                foreach ($sql_ary as $sql)

                {

                        $result = $db->sql_query($sql);

                        while ($row = $db->sql_fetchrow($result))

                        {

                                $hold_ary[$row['user_id']][$row['forum_id']][$row['auth_option']] = $row['auth_setting'];

                        }

                        $db->sql_freeresult($result);

                }

                return $hold_ary;

        }

        /**

        * Get raw group based permission settings

        */

        function acl_group_raw_data($group_id = false, $opts = false, $forum_id = false)

        {

                global $db;

                $sql_group = ($group_id !== false) ? ((!is_array($group_id)) ? 'group_id = ' . (int) $group_id : $db->sql_in_set('group_id', array_map('intval', $group_id))) : '';

                $sql_forum = ($forum_id !== false) ? ((!is_array($forum_id)) ? 'AND a.forum_id = ' . (int) $forum_id : 'AND ' . $db->sql_in_set('a.forum_id', array_map('intval', $forum_id))) : '';