Hi, This doesn't answer your question but may help you.. Have you looked at TStreamAdapter which "Implements OLE IStream on VCL TStream"? It's in the 'classes' unit. Could save you a lot of time :)
Chris > -----Original Message----- > From: Vaughan, Benjamin Carl [mailto:[EMAIL PROTECTED]] > Sent: Friday, 27 September 2002 11:48 a.m. > To: Multiple recipients of list delphi > Subject: [DUG]: A COM interface for a TStream object > > > Hi All, > > I am attempting to write a COM interface for the TStream > object, but I am > currently running into a problem. The current issue that I am > facing is with > my CopyFrom method which I have pasted below. > > The problem that I have is that when the method completes it raises an > access violation (basically right on the 'end;' line). I can however > confirm that the copying of the stream does occur successfully. > > If anyone has any ideas on what is wrong with my CopyFrom > method any help is > appreciated. I also found if I don't call the > "Source.ReadBuffer(Buffer^, N);" line the error will not occur. > > Ben Vaughan > ================================ > Systems Architect > Business Education Online > University of Auckland > ================================ > Old Choral Hall, 7 Symonds St, Auckland > (P) +64 9 3737599 x2514 (F) +64 9 3737430 > > > function TMyStream.CopyFrom(const Source: IMyStream; Count: Integer): > Integer; > const > MaxBufSize = $F000; > var > BufSize, N: Integer; > Buffer: POleVariant1; > begin > if Count = 0 then > begin > Source.Position := 0; > Count := Source.Size; > end; > Result := Count; > if Count > MaxBufSize then BufSize := MaxBufSize else > BufSize := Count; > GetMem(Buffer, BufSize); > try > while Count <> 0 do > begin > if Count > BufSize then N := BufSize else N := Count; > Source.ReadBuffer(Buffer^, N); > WriteBuffer(Buffer^, N); > Dec(Count, N); > end; > finally > FreeMem(Buffer, BufSize); > end; > end; > > procedure TMyStream.ReadBuffer(var Buffer: OleVariant; Count: > Integer); > begin > fStream.ReadBuffer(Buffer,Count); > end; > > procedure TMyStream.WriteBuffer(var Buffer: OleVariant; > Count: Integer); > begin > fStream.WriteBuffer(Buffer,Count); > end; > > -------------------------------------------------------------- > ------------- > New Zealand Delphi Users group - Delphi List - > [EMAIL PROTECTED] > Website: http://www.delphi.org.nz > To UnSub, send email to: [EMAIL PROTECTED] > with body of "unsubscribe delphi" > Web Archive at: http://www.mail-archive.com/delphi%40delphi.org.nz/ > --------------------------------------------------------------------------- New Zealand Delphi Users group - Delphi List - [EMAIL PROTECTED] Website: http://www.delphi.org.nz To UnSub, send email to: [EMAIL PROTECTED] with body of "unsubscribe delphi" Web Archive at: http://www.mail-archive.com/delphi%40delphi.org.nz/
