Re: Bug/Oversight in gatchat/gatresult.c with negative numbers

[Denis Kenzior <denkenz@gmail.com>]

[-- Attachment #1: Type: text/plain, Size: 1722 bytes --]

Hi Alex,

> Yeah I think you are right and I am getting really irritated with them giving me 
> the run-around tbh.
> 

I sympathize, been there ;)

> 
> Yeah ok - what name do you suggest?

So there's a few things you can do actually:
- We do have g_at_result_next_unquoted_string.  You could try using that to 
obtain the negative <rsrp> and then just sscanf/strtol or whatever to convert it.
- We also have g_at_result_iter_raw_line() which can give you the raw result 
line.  It should be trivial to come up with some sscanf magic to parse the result.
- Just add a new g_at_result_iter_next_negative_number.  Or if you come up with 
a more descriptive word than negative, feel free.

> 
> Also there's a bigger problem here I think, which is that if I parse negative 
> values and try to pass them back via e.g. netmon interface then Ofono is 
> treating anything negative in there as an error.

oFono uses 27.007 as the interface between the driver and the core (and also for 
DBus API).  If it isn't defined in 27.007, then your driver has to sanitize it 
to a range that is defined in 27.007.  In your <rsrp> case any negative value 
would just be converted to a '0' which means < -140.

> 
> And the DBUS implementation is unsigned for values based on the thinking that AT 
> responses are non-negative.
> 

See above, the DBus implementation would be untouched.  If you need to 
*actually* know whether <rsrp> is -142 or other range that is not currently 
supported by 3GPP 27.007, then that is a bit nastier problem.

> So actually there are a number of invasive changes that seem to need to be made 
> to support negative numbers?
> 

Hopefully not?

Regards,
-Denis