Re: Hexadecimal and stream element arrays

[Ludovic Brenta <ludovic@ludovic-brenta.org>]

tonyg wrote on comp.lang.ada:
> On Apr 19, 4:44 pm, tonyg <tonytheg...@googlemail.com> wrote:
>
> > I have some data coming in from a serial port which I want to convert
> > to hexadecimal and display on the screen. I was wondering if anyone
> > knows of a simple way to do this?
>
> To make myself more clear I have already dealt with the serial comms
> bit, I am looking to display the stream I have already captured

You could use the predefined library to get a result using the Ada
"syntax for based literal" (ARM A.10.8(14)), e.g. 16#CE#.

   package Stream_Element_IO is
     new Ada.Text_IO.Modular_IO (Num => Ada.Streams.Stream_Element);

   E : Ada.Streams.Stream_Element := ...
begin
   Stream_Element_IO.Put (Item => E, Base => 16);

(There are variants of Put that send the output to a File_Type or to a
string).

If you want to avoid the 16## part, you can easily convert the
stream_elements to a string representation yourself like so:

function To_Hex (E : in Ada.Streams.Stream_Element) return String is
   -- Warning: not compiled and not tested...
   X : constant array (0 .. 15) of Character :=
     ('0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C',
'D', 'E', 'F');
   Result : String (1 .. Ada.Streams.Stream_Element'Size / 4); -- 1
hex digits = 4 bits
   Working_Copy : Ada.Streams.Stream_Element := E;
   use type Ada.Streams.Stream_Element;
   First_Character : Natural := 0;
   Base : constant := 16;
begin
   for K in reverse Result'Length loop
      Result (K) := X (Working_Copy mod Base);
      Working_Copy := Working_Copy / Base;
      if Working_Copy = 0 then
         First_Character := K;
         exit;
      end if;
   end loop;
   return Result (First_Character .. Result'Last);
end To_Hex;

Hope this helps.

--
Ludovic Brenta.