Hello Denis,
On Thu, 2011-03-10 at 00:19 +0200, Denis Kenzior wrote:
> Hi Jarko,
>
> On 03/08/2011 05:00 AM, Jarko Poutiainen wrote:
> > ---
> > gatchat/gatsyntax.c | 10 ++++++++--
> > 1 files changed, 8 insertions(+), 2 deletions(-)
> >
> > diff --git a/gatchat/gatsyntax.c b/gatchat/gatsyntax.c
> > index 2fc70b8..a85bc66 100644
> > --- a/gatchat/gatsyntax.c
> > +++ b/gatchat/gatsyntax.c
> > @@ -90,7 +90,11 @@ static GAtSyntaxResult gsmv1_feed(GAtSyntax *syntax,
> >
> > case GSMV1_STATE_INITIAL_CR:
> > if (byte == '\n')
> > - syntax->state = GSMV1_STATE_INITIAL_LF;
> > + if (*len == 2) {
>
> You simply cannot do this. The whole idea behind the state machine in
> GAtSyntax is that your data is a byte-stream. There are no markers, and
> you can make no assumptions on the length of the buffer that is fed into
> this function. e.g. if you're unlucky you can get:
>
> gsmv1_feed("\r")
> gsmv1_feed("\n")
>
Point taken.
>
> Is there any particular reason why CPOS is not re-using the prompting
> feature of AT commands and has to invent its own? If you think about
> this a bit harder you will realize that the spec is *completely* broken
> here and introduces a parser ambiguity which cannot be reliably fixed.
>
Well thinking about it a: I noticed the same thing when trying to
implement b: I didn't write specification c: I'm just the guy who was
supposed to implement this. So I agree doesn't make sense but need to
find some solution for this anyway.
> At this point my only suggestion is that you need to set a parser hint
> after every CPOS command sent to the modem. Or better yet, push a
> change request to 27.007 to use proper prompting procedures.
>
Ok I'm not quite sure what you mean. If you mean using syntax->set_state
with hint say G_AT_SYNTAX_EXPECT_PROMPT I still need to somehow get
state to G_AT_SYNTAX_RESULT_PROMPT which I can by if
G_AT_SYNTAX_EXPECT_PROMPT then GSMV1_STATE_PROMPT and then in gsmv1_feed
I check that if '\r' and then '\n' then G_AT_SYNTAX_RESULT_PROMPT.
Is that what you mean?
The next question is where do I call the set_hint and how? If on driver
the problem is that I need to get the driver to be aware of _GAtSyntax
or more precisely set_hint method. If on gatchat the problem is to check
if the command is +CPOS and do it efficiently.
What comes to making a change request to 27.007. I think that's a very
long road to take.
> Regards,
> -Denis
Br,
Jarko
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