Wireshark-dev: Re: [Wireshark-dev] [Wireshark-commits] rev 39143: /trunk/epan/dissectors/ /trun
From: Anders Broman <a.broman@xxxxxxxxxxxx>
Date: Tue, 27 Sep 2011 07:03:40 +0200
Martin Kaiser skrev 2011-09-26 23:28:
Dear all,

I wanted to discuss this as well to make sure that my next submissions
are in line with your policy, but you were faster ;-)

Thus wrote Maynard, Chris (Christopher.Maynard@xxxxxxxxx):

-----Original Message-----
   From me:
  Change ENC_NA to ENC_BIG_ENDIAN as i suppose this is a big endian
protocol and ENC_NA was erroneously used for irems bigger than i
byte
in some cases.
This is a good example of the problem that can occur with using
ENC_NA.
What problem can occur with ENC_NA here?

My assumption was that ENC_BIG_ENDIAN/_LITTLE_ENDIAN is only applicable
to multi-byte numeric values, i.e. FT_(U)INT16/32/64. For FT_(U)INT8 and
FT_BYTES, FT_STRING etc., I used ENC_NA.
In this case ENC_NA and ENC_BIG_ENDIAN does not make a difference as the actual value of the symbol
is the same presently
+ proto_tree_add_item(
+ tree, hf_dvbci_sac_msg_ctr, tvb, offset, 4, ENC_NA);
is wrong in principle as it's a multi byte field. Personally I think it makes sense to tag the one byte fields the same as the bulk of the multi byte fields in the dissector e.g ENC_BIG_ENDIAN or ENC_LITTLE_ENDIAN as it makes the code more symmetrical and easier to read ( avoids "Hmm why is this field ENC_NA").

In the case of
proto_tree_add_item(tree, hf_dvbci_file_hash,
 - tvb, offset, 16, ENC_NA);
+ tvb, offset, 16, ENC_BIG_ENDIAN);

I made a mistake as that's a FT_BYTES it should be ENC_NA I suppose. So you might want to check your code
and fix it in your next patch ;-)
Best regards
Anders

Anders' assumption is correct: all multi-byte values in DVB-CI are big
endian.

Best regards,

    Martin
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