[LeeCHeSSS]

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PHP Code:

// ###################### Start is member of #######################
// returns true/false if a $userinfo belongs to $usergroupid
// $userinfo must contain (userid, usergroupid, membergroupids)
function is_member_of($userinfo, $usergroupid)
{
        static $user_memberships;

        if (!is_array($user_memberships["$userinfo[userid]"])) {
                $user_memberships["$userinfo[userid]"] = fetch_membergroupids_array($userinfo);
        }

        if (is_array($usergroupid)) {
                for ($i = 0; $i < sizeof($usergroupid); $i++) {
                        if ($userinfo['usergroupid'] == $usergroupid[$i]) {
                                return true;
                        } else if (in_array($usergroupid[$i], $user_memberships["$userinfo[userid]"])) {
                                return true;
                        }
                }
        } else {
                if ($userinfo['usergroupid'] == $usergroupid) {
                        return true;
                } else {
                        return in_array($usergroupid, $user_memberships["$userinfo[userid]"]);
                }
        }
}