Wireshark · Wireshark-dev: Re: [Wireshark-dev] Is there a good way of handling bitfields with different bitmask offsets ?

["ronnie sahlberg" <ronniesahlberg@xxxxxxxxx>]

Not tested!
grab the hfinfo structure and modify the fields at runtime :

header_field_info *hfinfo;

hfinfo = proto_registrar_get_nth(hf_index);
hfinfo->bitmask = new bitmask
hfinfo->bitshift = new bit shift


very ugly.   it could work.


please do not contribute any code to wireshark that does anything like this  :-)



On Nov 13, 2007 5:01 AM, Neil Piercy <Neil.Piercy@xxxxxxxxxxxx> wrote:
> If the protocol has bitfields they can be defined in the hf structs, but
> what is the best way to cope if these fields can be at different bit
> offsets within the byte ? E.g. a 4 bit field which can occur as the
> lower 4 bits or the upper 4 bits of a byte.
>
> The more I think about it, the general way would be to add a bit offset
> to _every_ existing proto_tree_add_*() to go with the existing byte
> offset, but is there a simpler way which
> A) maintains the bitmask display in the main packet field view which the
> hf bitmasks provide.
> B) isnt just a text decode - is based on hf entries.
>
> Neil
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