🚀 go-pugleaf

In article <1drej9INN8t8@svcase.sp.paramax.com> scase@email.sp.paramax.com (Steve Case) writes:
>I am trying to understand the various ASN.1 encoding and I cannot seem
>to understand how the indefinite form for the length octets can possibly
>work!  To make things simple, let me give you a specific example and
>hopefully someone can clarify the situation for me.
>
>Let's assume we are encoding a bitstring value.  The particular bitstring
>to be encoded is '0900000009'H.  If I use the indefinite length format, 
>wouldn't this be encoded as follows:
>
>   BitString Length Contents
>   23        80     000900000009
>
>   EOC       Length
>   00        00
>
>
>My question, then, is when decoding this octet stream, how do you know
>that the bitstring is '0900000009'H and not '09'H or '090'H or '0900'H
>or '09000'H?  All three of these seem to be possible decodings?

Indefinite encodings are only legal on constructed types.  Primitive
types must always use definite length encoding.  Thus you can always
find the EOC encoding which terminates the innermost indefinite length
encoding that it terminates.  These things can be nested!!!

>Thank you for any assistance you might be able to give me.
>
>Regards,
>Steve Case
>scase@planet8.sp.paramax.com

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