> Does anybody know whether BER would require the encoding of the type > information for every data field of a sequence? I know that if it uses the > UNIVERSAL class, the tags can tell what is the type that is encoded in the > VALUE field. However, if the sequence has some optional fields, than the > encoding should use CONTEXT SPECIFIC tags ..
Not necessarily. > and the tags have different > meaning now (they must uniquely identify the fields of the structure). > Therefore the type information of the encoded fields is lost. > Is this a correct interpretation of the BER standard? No. You can use EXPLICIT tagging which will include both the CONTEXT and UNIVERSAL tags. Regards, Ed Day Objective Systems, Inc. REAL WORLD ASN.1 AND XML SOLUTIONS Tel: +1 (484) 875-9841 Fax: +1 (484) 875-9830 Toll-free: (877) 307-6855 (USA only) mailto:[EMAIL PROTECTED] http://www.obj-sys.com ----- Original Message ----- From: "Eduard Lascu" <[EMAIL PROTECTED]> To: "Asn1" <[email protected]> Sent: Monday, May 16, 2005 3:31 PM Subject: [ASN1] Does BER require the encoding of the type information? > > Hello everybody, > > Does anybody know whether BER would require the encoding of the type > information for every data field of a sequence? I know that if it uses the > UNIVERSAL class, the tags can tell what is the type that is encoded in the > VALUE field. However, if the sequence has some optional fields, than the > encoding should use CONTEXT SPECIFIC tags and the tags have different > meaning now (they must uniquely identify the fields of the structure). > Therefore the type information of the encoded fields is lost. > Is this a correct interpretation of the BER standard? > > Best regards and thanks for the help, > Eddie L. > > Eddie Lascu > Senior Software Developer, Associate > IBI Group > 230 Richmond St. W., 5th Floor > Toronto ON M5V 1V6 > Tel. (416) 596-1930 x312 > Fax. (416) 596-0644 > www.ibigroup.com > > > NOTE: This e-mail message and attachments may contain privileged and > confidential information. If you have received this message in error, > please immediately notify the sender and delete this e-mail message. > > "NOTE: Ce courriel peut contenir de l'information privil�gi�e et > confidentielle. Si vous avez re�u ce message par erreur, veuillez le > mentionner imm�diatement � l'exp�diteur et effacer ce courriel." > > _______________________________________________ > ASN1 mailing list > [email protected] > http://lists.asn1.org/mailman/listinfo/asn1 > > _______________________________________________ ASN1 mailing list [email protected] http://lists.asn1.org/mailman/listinfo/asn1
