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Re: Lua dissector adds trees but they have (null) in front of the tree label


From: Richard Sharpe <realrichardsharpe () gmail com>
Date: Sat, 20 Oct 2018 12:31:07 -0700

On Sat, Oct 20, 2018 at 12:25 PM Richard Sharpe
<realrichardsharpe () gmail com> wrote:

Hi folks,

I have a small generated capture that has a three-byte header, with
the first being a function code and the next two being the length.

I handle them like this in Lua:

    local t_header = tree:add(buffer, label)
    t_header:add(f_function, buffer(offset, 1))
    offset = offset + 1
    t_header:add(f_length, buffer(offset, 2))
    offset = offset + 2

However, each subtree (there is another as well), appears with
'(null)' in front of it.

At first I thought maybe it was because I did not specify the length
of the buffer, so I added this at the end:

    t_header:set_len(offset - saved_offset)

However, that has not fixed the problem.

Does anyone know what I need to do to fix this?

Hmmm, I may have figured out what I did wrong.

I need to specify the buffer start location and length, and the
easiest thing is to treat it as a 1-byte item to start with.

-- 
Regards,
Richard Sharpe
(何以解憂?唯有杜康。--曹操)(传说杜康是酒的发明者)
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