Author: Tomas Rutkauskas

How to convert a TMemoryStream to an OLE variant and vice versa

Answer:
1   
2   function MemoryStreamToOleVariant(Strm: TMemoryStream): OleVariant;
3   var
4     Data: PByteArray;
5   begin
6     Result := VarArrayCreate([0, Strm.Size - 1], varByte);
7     Data := VarArrayLock(Result);
8     try
9       Strm.Position := 0;
10      Strm.ReadBuffer(Data^, Strm.Size);
11    finally
12      VarArrayUnlock(Result);
13    end;
14  end;
15  
16  function OleVariantToMemoryStream(OV: OleVariant): TMemoryStream;
17  var
18    Data: PByteArray;
19    Size: integer;
20  begin
21    Result := TMemoryStream.Create;
22    try
23      Size := VarArrayHighBound(OV, 1) - VarArrayLowBound
24        (OV, 1) + 1;
25      Data := VarArrayLock(OV);
26      try
27        Result.Position := 0;
28        Result.WriteBuffer(Data^, Size);
29      finally
30        VarArrayUnlock(OV);
31      end;
32    except
33      Result.Free;
34      Result := nil;
35    end;
36  end;