[OTR-dev] sourceforge / parse.c in toolkit.c

[Bjorn Kuiper]

On 7/20/2013 6:49 PM, Ian Goldberg wrote:
> On Sat, Jul 20, 2013 at 06:33:49PM -0400, Bjorn Kuiper wrote:
>> Hi,
>>
>> Not sure if you want me to use sourceforge or this mailing list.
>>
>> I will try this mailing list first, because I know it is actively monitored.
>>
>> While working on my project I noticed the following code in parse.c
>> part of the toolkit folder.
>>
>> ----
>>      if (memcmp(bufp, "\x00\x01\x03", 3) && memcmp(bufp,
>> "\x00\x03\x03", 3) &&
>> 	memcmp(bufp, "\x00\x02\x03", 3)) goto inv;
>> ----
>>
>> I don't think this code is doing anything at the moment because the
>> "&&" (AND) signs would need to be replaced with the "||" (OR) to
>> work properly.
>>
>> Greetings Bjorn
>
> Hmm?  memcmp returns 0 on match, and non-0 on mismatch (in fact, it's
> more specific than this, but that's not important for this snippet).
>
> So memcmp(bufp, "foo", 3) says "bufp is *not* "foo"".
>
> The above snippet is "if bufp is not "\x00\x01\x03", AND it's not
> "\x00\x03\x03", AND it's not "\x00\x02\x03", then it's invalid".
>
> Why is that wrong?
>
>     - Ian (admittedly under the weather at the moment, and so may be
>            having backwards-brain :-p )

No, you are right. I didn't consider memcmp would return 0 on match. I 
guess i was actually under the weather... Well to be honest, i don't 
program enough in C++ and should have had a proper look at the 
documentation of memcmp .

Sorry and thanks for responding,

Greetings Bjorn