Thanks for the list tip!
I'm just now developing an application using CF's BitAnd() function.
In my application, I currently have the following permission levels:
Level User Description
Permission
DB value for
BitAnd
1 1 Public - future permission level
READ selected pages
2 3 Basic Project Read User
Read all pages
4 7 Basic Project Content User
Read all, Add/Update selected data
8 15 Project Manager User
Read all, Add/Update all
16 31 me ;-)
Since a User with a larger permission value must also have the access all
Users with lesser permission values do, CF's BitAnd enables only 5
permission levels. I'm concerned the client might come up with additional
permission levels/groups in the future, thereby defeating my use of BitAnd,
and forcing me to modify code/user database/client database to use a list
instead of BitAnd.
Or have I missed a clever way to use BitAnd?
best, paul
PS> It sure helps to ask for help;-) Now that I've done so, I think the
simple solution to my problem is not to use BitAnd, but just adopt a
sequence of increasing numbers, for example: 5, 10, 15, 20, 25, etc (go by
5's to allow future insertion of new intermediate permission levels), and
verify a User's permission is greater than a target. That way, I still
only need to store a single number in the database as with BitAnd, and
don't need to go to using a list. Any comments?
At 10:48 AM 5/10/01 -0400, you wrote:
>Bit masks are cool, but remember that there is a limit to how much info you
>can pack in a bitmask because CF doesn't let you use the bit functions on
>anything of more than 32 bits. I have taken to using lists for this sort of
>thing because there's no practical limit to how many items it can contain
>and there are lots of useful list functions in CF.
>
>
>-----Original Message-----
>From: Ken Monroe [mailto:[EMAIL PROTECTED]]
>Sent: Wednesday, May 09, 2001 4:54 PM
>To: CF-Talk
>Subject: Bit Masks
>
>
>Hello!
>
>I believe that someone once gave a presentation at one of the CFUGs about
>using bit masks, also know as Right Bit AND, to set up security access
>levels. This wasn't the same as the presentation at the Fig Leaf site
>that's slight more oriented towards hierarchy uses. I've looked at all the
>CFUG sites linked to from the Allaire site but I can't find the
>presentation. Does anyone recall where the presentation was made and/or how
>to get the presentation file?
>
>Thx
>
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