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Re: [perl #117661] perlfunc/perlpacktut pack w documentation

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From:
Tony Cook
Date:
April 18, 2013 22:59
Subject:
Re: [perl #117661] perlfunc/perlpacktut pack w documentation
Message ID:
20130418225914.GB3954@mars.tony.develop-help.com
On Thu, Apr 18, 2013 at 08:04:39AM -0700, schmorp@schmorp.de (via RT) wrote:
> [Please describe your issue here]
> 
> perldoc -f pack tells us:
> 
>    w  A BER compressed integer (not an ASN.1 BER, see perlpacktut for details).
> 
> Ok, it's not an ASN.1 BER integer, still, it's an ASN.1 BER subidentifier
> (and is happily used to decode these in e.g. Net::SNMP).
> 
> Anyways, heading to perlpacktut to see why there is strong negation of
> it's ASN.1 BER qualities, I find... nothing.
> 
> The only thing I can find is "Another Portable Binary Encoding", which tells us:
> 
>    (Details can be found at <http://Casbah.org/>, the Scarab project.)
> 
> Apparently, that domain fell off the internet in 2008. Looking at it
> in the wayback machine still shows that there are no details at that
> URL. At all. If there ever was, it must have been buried deep inside that
> domain at some other URL. It looks more like some shameless plug for some
> project, and in any case, perl now refers to some kind of recycling shop
> or so.

I suspect it refers to this, or a similar definition:

https://github.com/mworks-project/mw_scarab/blob/master/Scarab-0.1.00d19/doc/binary-serialization.txt#L201

There's another note in the same file complaining about the usage:

https://github.com/mworks-project/mw_scarab/blob/master/Scarab-0.1.00d19/doc/binary-serialization.txt#L151

> Here are my suggestions to improve this situation:
> 
> 1. drop the "not an ASN.1 BER" comment, or at least qualify it, like
>    "like an ASN.1 BER subidentifier, not a BER integer".
> 
>    At the very least the description of BER subidentifier encoding in
>    X.209:198811 6.22 is much more concise than any I found in the perl
>    documentation, so saying it isn't an ASN.1 BER is more confusing than
>    helpful, because by all means it is.

"the integer encoding used for ASN.1 subidentifiers"

> 2. remove the url in perlpacktut.

I wasn't able to find a good linkable reference either.

http://luca.ntop.org/Teaching/Appunti/asn1.html

provides a good description, but I didn't see any fragment ids.

Tony

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