procedure TMainForm.Button1Click(Sender: TObject);
var
  f1,f2:TFileStream;
  b1,b2:byte;
  w:word;
  i:integer;
begin
  //check
  if FileExists('e:\test.txt')=false then exit;
  //OBJ
  f1:=TFileStream.Create('e:\test.txt',fmOpenRead);
  if f1.Size=0 then exit;
  f2:=TFileStream.Create('e:\new.txt',fmCreate);
  //reset
  f1.Position:=0;
  f2.Position:=0;
  //檢查大小是否剛好為偶數
  if f1.Size mod 2=0 then
    for i:=0 to (f1.Size div 2)-1 do
      begin
        f1.ReadBuffer(b1,1);
        f1.ReadBuffer(b2,1);
        w:=b1 b2*256;
        f2.WriteBuffer(w,2);
      end//for
  else
    begin
      for i:=0 to (f1.Size div 2)-1 do
        begin
          f1.ReadBuffer(b1,1);
          f1.ReadBuffer(b2,1);
          w:=b1 b2*256;
          f2.WriteBuffer(w,2);
        end;//for
      f1.ReadBuffer(b1,1);
      f2.WriteBuffer(b1,1);
    end;//else
  //Free
  f1.Free;
  f2.Free;
end;