Re: Hexadecimal and stream element arrays

[tonyg <tonythegair@googlemail.com>]

On Apr 19, 6:02 pm, tonyg <tonytheg...@googlemail.com> wrote:
> On Apr 19, 5:27 pm, tonyg <tonytheg...@googlemail.com> wrote:
>
>
>
> > On Apr 19, 5:24 pm, Ludovic Brenta <ludo...@ludovic-brenta.org> wrote:
>
> > > 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.
>
> > Thanks Ludovic I'll try that.
>
> I tried the first way and thought I would prefer the hex.
> I got an error as the compiler is expecting a second value in the
> range.
> Second way is definetly the way forward I think , Thanks again for a
> very detailed reply, its saved me loads of time :)

Changed the hex function to
   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'First .. Result'Length loop
      		Result (K) := X (integer(Working_Copy) mod integer (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;

It still seems to be dropping a few zeros though and I'm stumped where
its going wrong