A Database for Squeak: Question on DataStream

Mark Guzdial guzdial at cc.gatech.edu
Wed Mar 18 16:57:27 UTC 1998

I have built a small database in Squeak -- a FileDictionary, available at
http://guzdial.cc.gatech.edu/st/dbdict.17Mar445pm.cs  (See examples in

What I've done is to subclass DataStream to create a PositionableDataStream
that allows me to set the position of the underlying bytestream.  I know
that in ReferenceStream this is super dangerous, because objects are
written only once and the position flies all over the place during a read.
But for DataStream, I think that I can safely set the position for reading
given objects (or to the end of the file) if I only set the position to
known start positions of objects, because DataStream doesn't deal with
multiple refs, or cycles, or recursive links.

Is this true?  Am I making a safe assumption?


Mark Guzdial : Georgia Tech : College of Computing : Atlanta, GA 30332-0280
(404) 894-5618 : Fax (404) 894-0673 : guzdial at cc.gatech.edu

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