Generic asn.1 parser

Raimo Niskanen raimo@REDACTED
Thu Apr 12 10:22:27 CEST 2001

Sean Hinde wrote:
> > On Wed, 11 Apr 2001, Sean Hinde wrote:
> >
> > >I use atoms quite a bit - does anyone have a good feel for the
> > >performance impact of this over using integers for matching and
> > >tagging?
> >
> > There should be no performance difference.
> But doesn't it do some form of lookup in the atom table?

Internally, atoms are tagged integers. This means that comparisions for
equality and pattern matches are just as simple as for integers.
Construction of an atom, however, results in an insertion into the atom
table, which is some kind of fast hash table. 

Compiled atoms are inserted in the atom table sometime when the code is
loaded, thus possibly affecting the load time, marginally. What may be a
catch is to construct atoms on the fly, and to construct an infinite
number of them (due to random runtime data). This way you can exhaust
the atom table since atoms are never removed therefrom.

/ Raimo Niskanen, Ericsson UAB, Erlang/OTP

> Sean
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