tcp/src/common/StreamRdClass.m3


 Copyright 1999-2003 John D. Polstra.
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 *      This product includes software developed by John D. Polstra.
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 * $Id: StreamRdClass.m3.html,v 1.3 2010-04-29 17:20:11 wagner Exp $ 

MODULE StreamRdClass EXPORTS StreamRd, StreamRdClass;

IMPORT RdClass;

CONST
  Threshold = LAST(CARDINAL) DIV 2;

PROCEDURE ByteCount(srd: T): LONGREAL =
  BEGIN
    RdClass.Lock(srd);
    TRY
      RETURN srd.offset + FLOAT(srd.cur, LONGREAL);
    FINALLY
      RdClass.Unlock(srd);
    END;
  END ByteCount;

PROCEDURE DontOverflow(srd: T) =
  (* The reader is already locked. *)
  BEGIN
    IF srd.hi >= Threshold THEN
      srd.offset := srd.offset + FLOAT(srd.lo, LONGREAL);
      DEC(srd.hi, srd.lo);
      DEC(srd.cur, srd.lo);
      srd.lo := 0;
    END;
  END DontOverflow;

BEGIN
END StreamRdClass.