asn1: swapped fields

Bertil Karlsson <>
Wed Jan 8 14:03:56 CET 2003


Hello,

This is definitely a bug, and it will be corrected in the next patch.

/Bertil Karlsson

"Jozsef Berces (QCZ)" wrote:
> 
> Hi,
> 
> I have compiled RANAP with asn1ct and the decoder erlang code produces swapped fields for ProtocolIE-FieldPair: firstValue and secondCriticality are swapped in the resulting record. Here I am posting a simplified example.
> 
> If you try to compile the attached file RAB-SetupOrModifyList.asn with option per, then for the sequence
> 
> ProtocolIE-FieldPair {RANAP-PROTOCOL-IES-PAIR : IEsSetParam} ::= SEQUENCE {
>         id                              RANAP-PROTOCOL-IES-PAIR.&id                     ({IEsSetParam}),
>         firstCriticality                RANAP-PROTOCOL-IES-PAIR.&firstCriticality       ({IEsSetParam}{@id}),
>         firstValue                      RANAP-PROTOCOL-IES-PAIR.&FirstValue             ({IEsSetParam}{@id}),
>         secondCriticality               RANAP-PROTOCOL-IES-PAIR.&secondCriticality      ({IEsSetParam}{@id}),
>         secondValue                     RANAP-PROTOCOL-IES-PAIR.&SecondValue            ({IEsSetParam}{@id})
> }
> 
> the erlang code will be
> 
> 'dec_RAB-SetupOrModifyList_SEQOF_ProtocolIE-FieldPair'(Bytes,Telltype) ->
> 
> %%  attribute number 1 with type id
> {Term1,Bytes1} = ?RT_PER:decode_integer(Bytes,[{'ValueRange',{0,65535}}]),
> 
> %%  attribute number 2 with type firstCriticality
> {Term2,Bytes2} = ?RT_PER:decode_enumerated(Bytes1,[{'ValueRange',{0,2}}],{reject,ignore,notify}),
> 
> %%  attribute number 3 with type FirstValue
> {Tmpterm1, Bytes3} = ?RT_PER:decode_open_type(Bytes2, []),
> 
> %%  attribute number 4 with type secondCriticality
> {Term3,Bytes4} = ?RT_PER:decode_enumerated(Bytes3,[{'ValueRange',{0,2}}],{reject,ignore,notify}),
> 
> %%  attribute number 5 with type SecondValue
> {Tmpterm2, Bytes5} = ?RT_PER:decode_open_type(Bytes4, []),
> DecObjidTerm1 =
>    'getdec_RAB-SetupOrModifyItem-IEs'(id, Term1),
> {Term4, _} =
>    case DecObjidTerm1('FirstValue', Tmpterm1, telltype,[]) of
>       {'EXIT', Reason1} ->
>          exit({'Type not compatible with table constraint',Reason1});
>       Tmpterm3 ->
>          Tmpterm3
>    end,
> {Term5, _} =
>    case DecObjidTerm1('SecondValue', Tmpterm2, telltype,[]) of
>       {'EXIT', Reason2} ->
>          exit({'Type not compatible with table constraint',Reason2});
>       Tmpterm4 ->
>          Tmpterm4
>    end,
> 
> {{'ProtocolIE-FieldPair',Term1,Term2,Term3,Term4,Term5},Bytes5}.
> 
> 
> It can be seen that attribute number 3 is assigned to Term4 and attribute number 4 goes to Term3. It seems that the problem is to have the 'getdec_RAB-SetupOrModifyItem-IEs'(id, Term1) call too late, so Term4 will receive attribute number 3.
> 
> I attached the results for different options: per, per_bin, and ber. per and per_bin are the same but ber is even worse (however, RANAP uses PER encoding)!
> 
> Could someone post a fix? Until then we have to modify the erang code manually.
> 
> Thanks in advance,
> Jozsef
> 
>   ------------------------------------------------------------------------
> 
>    RAB-SetupOrModifyList.asnName: RAB-SetupOrModifyList.asn
>                             Type: unspecified type (application/octet-stream)
> 
>                                     Name: RAB-SetupOrModifyList.ber.erl
>    RAB-SetupOrModifyList.ber.erl    Type: unspecified type (application/octet-stream)
>                                 Encoding: quoted-printable
> 
>                                     Name: RAB-SetupOrModifyList.per.erl
>    RAB-SetupOrModifyList.per.erl    Type: unspecified type (application/octet-stream)
>                                 Encoding: quoted-printable
> 
>                                         Name: RAB-SetupOrModifyList.per_bin.erl
>    RAB-SetupOrModifyList.per_bin.erl    Type: unspecified type (application/octet-stream)
>                                     Encoding: quoted-printable

-- 
/ Bertil Karlsson



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