Wireshark · Ethereal-dev: Re: [Ethereal-dev] Which characters can i compare using ' tvb_get_guint8'

[Guy Harris <guy@xxxxxxxxxxxx>]

On Thursday, July 31, 2003, at 7:18 AM, Anders Broman (TN/EAB) wrote:

> Shold'nt the following coding work?

Yes.

> 	guint8		tempchar;
>
> 	tempchar = tvb_get_guint8(tvb, tvb_previous_offset );
> 	
> 	switch ( tempchar ){
> 		/* domainAddress */
> 		case '[':
> 			tvb_current_offset = tvb_find_guint8(tvb, tvb_previous_offset, 
> tvb_len, ']');
>
> I don't get a match eventhoug I'm prety certain that tempchar holds '['

By "I don't get a match" do you mean that the "switch" statement 
doesn't go to the '[' case, or do you mean that "tvb_find_guint8()" 
doesn't find a ']'?

If the former, then either

	1) "tempchar" doesn't, in fact, contain a '[' ('[' doesn't have the 
8th bit set in ASCII, so "guint8" vs. "char" won't matter)

or

	2) you have a buggy C compiler.

If the latter, then the existence of a '[' at "tvb_previous_offset" 
doesn't necessarily imply the existence of a ']' later in the packet 
(e.g., the snapshot length might have been short enough to cut the 
packet off, or the packet might be malformed).