Posted by Michael B. Trausch on 07/08/05 20:10

I have a question regarding bitwise operators, I've been trying to
figure this out for about two days now, and I just can't seem to get it.
What I'm trying to do is use a variable to hold a bitmask of 'flags'
for users on a website. The function below is supposed to be a search
function for one of those flags in a particular thing.

The idea is that when something calls userId(), it should get to see
what type of user flags that are supported. Now I've moved things
around, and it seems like the only if that ever executes is the first
one, the code doesn't ever reach any of the elseif blocks.

I want the function to search for the first user that it finds has a bit
set in the bitmask and return the userId as supplied by the cookie that
represents that bitmask.

Optionally, userId() can be called with one of the arguments specifying
a particular usertype to look for that particular usertype. The user
can be logged into multiple sections of the site at a time, so if
they're entering something where they need the USER_ADMIN privilege, I
should be able to call userId(USER_ADMIN) and get their UID if they're
an admin and E_NOT_LOGGED_IN if they're not logged in as an admin. Same
goes for any of the options that are defined. Can anyone else see what
is wrong with this?

Thanks for the help in advance.


Constants defined for USER_*:
=============================

define('USER_NOBODY', 0x00000000);
define('USER_SEEKER', 0x00000001);
define('USER_MEMPL', 0x00000002);
define('USER_SEMPL', 0x00000004);
define('USER_ADMIN', 0x00000008);
define('USER_ANYBODY', 0xffffffff);

Code that isn't working:
========================

function userId($pref = USER_ANYBODY)
{
/*
* If the user is logged in, this will return their user ID.
* If they are not, then it won't. If more then one user is
* logged in, this function will prefer MEMPL and SEMPL types
* over any other, unless specified by $pref.
*/

$uT = userType();

if(userAccess($uT, $pref))
{
/*
* The usertype that we're looking for is logged in.
*/

if(($pref & USER_SEEKER) > 0)
{
$tmpCookie = $_COOKIE['seeker'];
list($id, $i, $i, $i, $i, $i, $i) = explode(':', $tmpCookie);

return($id);
}

elseif(($pref & USER_MEMPL) > 0)
{
$tmpCookie = $_COOKIE['mEmpl'];
list($id, $i, $i, $i, $i, $i, $i) = explode(':', $tmpCookie);

return($id);
}

elseif(($pref & USER_SEMPL) > 0)
{
$tmpCookie = $_COOKIE['sEmpl'];
list($id, $i, $i, $i, $i, $i, $i) = explode(':', $tmpCookie);

return($id);
}

elseif(($pref & USER_ADMIN) > 0)
{
$tmpCookie = $_COOKIE['admin'];
list($id, $i, $i, $i, $i, $i, $i) = explode(':', $tmpCookie);

return($id);
}
}

// Oops. We don't have anything to do, return E_NOT_LOGGED_IN.

return(E_NOT_LOGGED_IN);
}

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