Wireshark · Wireshark-dev: Re: [Wireshark-dev] [Wireshark-users] bit operations are missing from lua bindings?

[Sam Roberts <vieuxtech@xxxxxxxxx>]

2009/6/4 Stig Bjørlykke <stig@xxxxxxxxxxxxx>:
> On Thu, Jun 4, 2009 at 6:58 PM, Sam Roberts <vieuxtech@xxxxxxxxx> wrote:
>> At least, I can't find any lua bindings for accessing bit fields, am I
>> missing them?
>
> Wireshark has no bitwise operators implemented for Lua bindings yet,
> so this is a correct observation.
>
> I don't think it should involve too much work implementing the most
> used ones (and, or, xor, bitshifting)  in the wireshark sources, but
> if the MIT license is GPLv2 compatible I find no reason to not use it
> as-is?

It's not a bad idea to have bit operations, and
http://bitop.luajit.org/ is the best one around, but thinking about a
more wiresharkish way of doing what I wanted to do...

> Moving this thread to the developer list.

When I add a field to the tree, I get to specify the mask, and it will
mask and shift bits out and display them nicely, what I need is a way
of accessing those bits, so I can act on them.

If  TvbRange_methods supported a :bitrange(pos, len) method, that
would mask and shift out a bitrange, and return it as a number, that
would be great. len could be optional, and default to 1, so:

r = buffer(9,2)
r:bitfield(1) -- value of bit 1
r:bitfield(7,2) -- value of bits {7,8}

...

Cheers,
Sam