Bugfix/Code Adjustment for TBinaryObjectReader
lazarus / 7-LCL

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SiMozzer · 2004-08-18 22:32

Folks,

I've just started to use and appreciate FPC & Lazarus and have found a
small bug in TBinaryObjectReader. 

The bug can be reproduced by creating a TReader with::

 TReader.Create(nil,BUFF_SIZE); { <- It is 'legal' to create a Tfiler
assigned to a 'nil' stream
                                                       but maybe a bit
stupid )
  try
    ///... more code
  finally
     TReader.Free; // <- This line will cause an access violation
  end;

 The code crashes because the internal TBinaryObjectReader attempts to
access the stream in its destrucrtor without first testing if it is
assigned. The following adjustment prevents the GPF ::

destructor TBinaryObjectReader.Destroy;
begin
  If Assigned(FStream) then  //<--- **test added here**
    { Seek back the amount of bytes that we didn't process until now:
}
    FStream.Seek(Integer(FBufPos) - Integer(FBufEnd), soFromCurrent);

  if Assigned(FBuffer) then
    FreeMem(FBuffer, FBufSize);

  inherited Destroy;
end;

what are your thoughts?

R.E.S.P.E.C.T (jus like Franklin))

Si Mozzer

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Anonymous · 2004-10-14 22:44

What Can I think  - happy bug hunter
should submit a bugfix to merge into code...