Копирование большого файла в буфер обмена

Code:

function _hread(FileHandle: word; BufPtr: pointer;

ByteCount: longint): longint; far;

external 'KERNEL' index 349;

procedure CopyFileToClipboard(const fname: string);

var

hmem, hFile: THandle;

size: LongInt;

p: Pointer;

begin

hFile := FileOpen(fname, fmOpenRead);

try

   size := FileSeek(hFile, 0, 2);

   FileSeek(hfile, 0, 0);

   if size > 0 then

   begin

     hmem := GlobalAlloc(GHND, size);

     if hMem <> 0 then

     begin

       p := GlobalLock(hMem);

       if p <> nil then

       begin

         _hread(hFile, p, size);

         GlobalUnlock(hMem);

         Clipboard.SetAsHandle(CF_TEXT, hMem);

       end

       else

         GlobalFree(hMem);

     end;

   end;

finally

   FileClose(hFile);

end;

end;

procedure TForm1.SpeedButton2Click(Sender: TObject);

var

fname: string[128];

begin

if OpenDialog1.Execute then

begin

   fname := OpenDialog1.Filename;

   CopyFileToClipboard(fname);

end;

end;