problems compiling H.323 ASN.1

Bertil Karlsson <>
Fri Nov 22 14:39:43 CET 2002


Hello,

Sorry for beeing late with a responce on this. Constraints are
implemented (most of them anyway). I didn't know this was a PER protocol
at first. For PER the constraint is crucial in that it affects how the
message is encoded/decoded. Two types of the same ASN.1 type with
different constraints will result in different encodings.

The reason why the ASN.1 compiler fails in this case is unfortunately a
bug, and it will be corrected in the next patch.

If you want the _fastest_ encode/decode you should compile the files
with 
For BER:
>asn1ct:compile(ASN1File, [ber_bin,optimize]).

For PER:
>asn1ct:compile(ASN1File, [per_bin]).
generates faster code than
>asn1ct:compile(ASN1File, [per]).
but the fastest code you will get by:
>asn1ct:compile(ASN1File, [per_bin,optimize]).
in this case the PER encode is partly done by a driver.


Bruce Fitzsimons wrote:
> 
> Hi Vance,
> 
> Did you get an answer to this? I believe that constraints are not
> implemented yet, removing them has no effect on the protocol exchanges (its
> just validation for what you can put into them).
> 
> By the way, H.323 is ASN.1 PER so you need:
> 
> 1>asn1ct:compile("H323-MESSAGES.asn", [per]).
> 
> or it will default to ASN.1 BER.
> 
> (if you knew this already I apologise)
> 
> I've lost all my files. Grrr. But I'm interested enough to get all the
> H.323v4 files and compile them. Almost there :-)
> 
> /Bruce
> 
> ----- Original Message -----
> From: "Vance Shipley" <>
> To: <>
> Sent: Wednesday, November 20, 2002 6:14 PM
> Subject: Re: problems compiling H.323 ASN.1
> 
> >
> > After fixing the other problems I am left with the following.
> > I see the reason as not_implemented.  What is it that is not
> > implemented?
> >
> > -Vance
> >
> >
> > 9> asn1ct:compile("H323-MESSAGES.asn").
> > Erlang ASN.1 version "1.4" compiling "H323-MESSAGES.asn"
> > Compiler Options: []
> > asn1error:13:'H323-MESSAGES':'H323-UserInformation' {asn1,
> >                                                         {not_implemented,
> >

> {merge_constraints,
> >
> [{'PermittedAlphabet',
> >
> {'SingleValue',
> >
> "#*0123456789abc"}}]}}}
> > asn1error:706:'H323-MESSAGES':'GSM-UIM' {asn1,
> >                                             {not_implemented,
> >                                                 {merge_constraints,
> >                                                     [{'PermittedAlphabet',
> >                                                          {'SingleValue',
> >
> "#*0123456789abc"}}]}}}
> > {error,{asn1,[{error,{type,13,
> >                            'H323-MESSAGES',
> >                            'H323-UserInformation',
> >                            {asn1,{not_implemented,
> >                                      {merge_constraints,
> >                                          [{'PermittedAlphabet',
> >                                               {'SingleValue',
> >
> "#*0123456789abc"}}]}}}}},
> >               {error,{type,706,
> >                            'H323-MESSAGES',
> >                            'GSM-UIM',
> >                            {asn1,{not_implemented,
> >                                      {merge_constraints,
> >                                          [{'PermittedAlphabet',
> >                                               {'SingleValue',
> >
> "#*0123456789abc"}}]}}}}}]}}
> >

-- 
/ Bertil Karlsson



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