function FindInMemStream(Stream: TBytesStream; What: string): Integer;
var
 bufBuffer, bufBuffer2: array [0 .. 254] of Char;
 i: Integer;
begin
 Result := 0;
 i := 0;
 FillChar(bufBuffer, 255, #0);
 FillChar(bufBuffer2, 255, #0);
 StrPCopy(@bufBuffer2, What);
 Stream.Position := 0;
 while Stream.Position <> Stream.Size do
  begin
   Stream.Read(bufBuffer[0], Length(What));
   if CompareMem(@bufBuffer, @bufBuffer2, Length(What)) then
    begin
     Result := Stream.Position - Length(What);
     Exit;
    end;
   i := i + 1;
   Stream.Seek(i, 0)
  end;
end;