Wireshark · Wireshark-dev: Re: [Wireshark-dev] signedness of comparison functions in ftype-integer.c

["Martin Mathieson" <martin.r.mathieson@xxxxxxxxxxxxxx>]

On 1/3/07, Guy Harris <guy@xxxxxxxxxxxx> wrote:
> Martin Mathieson wrote:
>
> > For the more general problem, I see 2 possible solutions:
> > (1) have both signed and values in the union, and use the appropriate
> > signed or unsigned parts of the union in the comparison functions
> > (2) leave the union as it is with unsigned members, cast values in all
> > the signed versions instead of the unsigned versions
>
> I vote for solution 1 (and have everything that adds a signed value to
> the protocol tree set the signed value in the union).

The attached patch tries to implement (1), and seems to work (in the
limited testing I've done). However, it ended up touching more files
than I expected (a couple of dissectors even!).  There are still 2 or
3 places where signed and unsigned FT types are still handled together
by treating the value as guint32, thus potentially losing -ve values
of FT_INT32 fields, I've preserved the existing behaviour for now.

I would appreciate if someone could review this patch.  It does
correct a real problem, although I expect signed 32 bit fields with
negative values are pretty rare in most protocols (I'd guess they're
more likely to appear as generated fields).  I suppose 64-bit
numerical fields theoretically have the same problem, but is
presumably even less likely to cause real problems...?

Best regards,
Martin

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