Comparer 2 fichiers

Function Are2FilesEqual(Const fileName1, fileName2: String ):Boolean;
Var
ms1,
ms2 : TMemoryStream;

Begin
Result := False;
ms1 := TMemoryStream.Create;
try
ms1.LoadFromFile(fileName1);
ms2:= TMemoryStream.Create;
try
ms2.LoadFromFile(fileName2);
If ms1.size = ms2.size Then
Result := CompareMem(ms1.Memory, ms2.memory, ms1.size);
finally
ms2.free;
end;
finally
ms1.free;
end
End;

procedure TForm1.Button1Click(Sender: TObject);
begin
if Opendialog1.Execute then
begin
if Opendialog2.Execute then
begin
if Are2FilesEqual(Opendialog1.FileName,Opendialog2.FileName) then
begin
ShowMessage('Fichiers identiques');
end;
end;
end;
end;