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Wireshark-dev: Re: [Wireshark-dev] Correct and efficient way of displaying bit fields?

From: Glenn Matthews <glenn.matthews@xxxxxxxxx>
Date: Mon, 10 Oct 2011 08:48:22 -0400
On Oct 7, 2011, at 5:22 PM, Kaul wrote:

> I'm struggling for some time now with displaying bitfields, I'm sure there must be something I'm overlooking, or it's just a bit difficult to do in Wireshark.
> 
> I have a 32bit, little endian field, which I'd like to parse the bits (as set/not set):
> Example:
> 05 00 00 00
> 
> 1 0 0 0 .... Feature A - set
> 0 0 0 0 ... Feature B - not set
> 0 0 1 0 ... Feature C - Set
> 
> 
> 1. Do I really have to create a hf_xxx for each? And use something like proto_tree_add_bits_item() ? I was hoping to do it in a single proto_tree_add_xxx() and pass it a single HF that would hold a VALS(...) which will describe all the attributes.

Take a look at proto_tree_add_bitmask(). You still have to create each hf_xxx since each bit (or group of bits) is a different parameter, but then a single call to proto_tree_add_bitmask will set up the subtree for the whole bitfield.

Glenn