suplib/src/EscapedRd.i3


 Copyright 1996-2003 John D. Polstra.
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The EscapedRd interface provides a subclass of Rd.T which decodes the record-oriented stream produced by an EscapedWr.T. See that interface for details of the protocol.

INTERFACE EscapedRd;

IMPORT Atom, Rd;

TYPE
  T <: Public;

  Public = Rd.T OBJECT METHODS
    init(rd: Rd.T;
	 maxChildRead: CARDINAL := LAST(CARDINAL);
	 closeChild: BOOLEAN := TRUE): T;
  END;
The optional parameter maxChildRead may be used to limit the amount of read-ahead done on the child when filling the 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 escaped reader will also cause the child reader to be closed. If it is FALSE, then the child reader will be left open.

VAR (* CONST *)
  InvalidEscape: Atom.T;
  PrematureEOF: Atom.T;
If the escaped reader detects a violation of the protocol, it raises Rd.Failure with an error list containing InvalidEscape or PrematureEOF.

END EscapedRd.