Copyright 1996-2003 John D. Polstra.
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* $Id: GzipRd.i3.html,v 1.3 2010-04-29 17:20:02 wagner Exp $
The GzipRd interface defines a subclass of StreamRd.T which reads from
a compressed stream, decompressing it in the process.
INTERFACE GzipRd;
IMPORT OSError, Rd, StreamRd;
TYPE
T <: Public;
Public = StreamRd.T OBJECT METHODS
init(rd: Rd.T;
maxChildRead: CARDINAL := LAST(CARDINAL);
closeChild: BOOLEAN := TRUE): T RAISES {OSError.E};
END;
The init method is supplied with a so-called child reader, which
must supply bytes directly from the compressed stream.
The optional parameter maxChildRead may be used to limit the
amount of read-ahead done on the child when filling the
decompression buffer. That sacrifices some efficiency, but it
tightens the relationship between the number of bytes read from
the parent and the number of bytes read from the child. (It is
useful when statistics are being gathered.)
If closeChild is TRUE (the default), then closing the Gzip reader
will also cause the child reader to be closed. If it is FALSE, then
the child reader will be left open.
PROCEDURE Cleanup(rd: T);
Frees all resources used by rd, without doing anything to the child.
Cleanup is a no-op if the resources have already been freed, e.g.,
by a call to Rd.Close.
END GzipRd.