Hi Bancroft Scott and Gy�rgy
Thank you for your help.
I have the following specific question.
Please consider the following definitions.
The encoding rule is ASN.1 PER (unaligned).
------------------------------------------------------------------------
Class-definitions DEFINITIONS AUTOMATIC TAGS ::=
BEGIN
myCHOICE_1 ::= CHOICE {
firstAlternative [9] FirstAlternative,
secondAlternative [8] SecondAlternative
}
mySEQUENCE_1 ::= SEQUENCE {
firstField [9] FirstField,
secondField [8] SecondField
}
myCHOICE_2 ::= CHOICE {
firstAlternative FirstAlternative,
secondAlternative SecondAlternative
}
mySEQUENCE_2 ::= SEQUENCE {
firstField FirstField,
secondField SecondField
}
END
------------------------------------------------------------------------
MyCHOICE_2 would be encoded as follows.
for firstAlternative: <0 i.e. prefix> <encoding of the
firstAlternative>
for secondAlternative: <1 i.e. prefix> <encoding of the
secondAlternative >
MySEQUENCE_2 would be encoded as follows.
<encoding of the firstField > <encoding of the secondField >
Questions:
----------
Will the specification of tags (9 and 8) in myCHOICE_1 effect the
prefix value of FirstAlternative and SecondAlternative?
If yes then how will the encoding of myCHOICE_1 be?
And will IMPLICIT or EXPLICIT tagging have different effects on
encoding of myCHOICE_1?
Will the specification of tags (9 and 8) in mySEQUENCE_1 effect the
encoding of mySEQUENCE_1?
Please provide us with pointers (Books/References), if any.
Thanks and Regards
Krishna
-----Original Message-----
From: Gyorgy Rethy (ETH) [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, November 20, 2001 4:10 PM
To: '[EMAIL PROTECTED]'
Subject: RE: [ASN.1] AUTOMATIC Tagging and Unaligned-PER
Hi,
No, not at all. I would say quite the opposit. Automatic tagging works only
on types, which does not contain "hand-written" tags. If textual taggs are
removed from a module, automatic tagging may allocate a different tag to
components of SEQUENCEs, SETs or alternatives of CHOICEs as the textual tag
was. This may cause a different re-ordering of SET components or CHOICE
alternatives as it would be with textual taggs and spoile encoding.
This is a different issue, that there may be modules not using automatic
tagging but tagged quite the same way manually as the automatic mechanism
would do.
By the way it is unimportant from this point of view if the encoding is
aligned or unaligned.
Best Regards, Gy�rgy
============================================
dr. Gy�rgy R�THY
Ericsson Communications Systems Hungary Lim.
Conformance Center
tel.: +36 1 437-7006; fax: +36 1 437-7767
mobile: +36 30 297-7862
e-mail: [EMAIL PROTECTED]
web: http://www.r.eth.ericsson.se/~ethgry
============================================
>-----Original Message-----
>From: Krishna Reddy Gaddam [mailto:[EMAIL PROTECTED]]
>Sent: Monday, November 19, 2001 9:58 AM
>To: [EMAIL PROTECTED]
>Cc: '[EMAIL PROTECTED]'
>Subject: [ASN.1] AUTOMATIC Tagging and Unaligned-PER
>
>
>Hi All
>
>Is it correct to say :
>--------------------
>If an ASN.1 module header says AUTOMATIC TAGS,
>the Unaligned-PER encoder need not bother to look into the any
>of the TAGS
>in the whole module.
>
>Other way of saying :
>---------------------
>Is the module is just equivalent to all the TAGS removed from
>the module ?
>
>
>Please clarify.
>
>Thanks in advance.
>
>Regards
>Krishna [mailto:[EMAIL PROTECTED]]
>
