------------------------------------------------------------------------------
------------------------------------------------------------------------------
-- This file is part of 'Finite Field Arithmetic', aka 'FFA'.               --
--                                                                          --
-- (C) 2018 Stanislav Datskovskiy ( www.loper-os.org )                      --
-- http://wot.deedbot.org/17215D118B7239507FAFED98B98228A001ABFFC7.html     --
--                                                                          --
-- You do not have, nor can you ever acquire the right to use, copy or      --
-- distribute this software ; Should you use this software for any purpose, --
-- or copy and distribute it to anyone or in any manner, you are breaking   --
-- the laws of whatever soi-disant jurisdiction, and you promise to         --
-- continue doing so for the indefinite future. In any case, please         --
-- always : read and understand any software ; verify any PGP signatures    --
-- that you use - for any purpose.                                          --
--                                                                          --
-- See also http://trilema.com/2015/a-new-software-licensing-paradigm .     --
------------------------------------------------------------------------------
------------------------------------------------------------------------------

with System; use System;

package body CmdLine is
   
   -- Test if GNAT's cmdline mechanism is available
   function Initialized return Boolean is
      gnat_argv : System.Address;
      pragma Import (C, gnat_argv, "gnat_argv");

   begin
      return gnat_argv /= System.Null_Address;
   end Initialized;
   
   
   -- Fill the provided string with the text of Number-th cmdline arg
   procedure Get_Argument(Number : in  Natural;
                          Result : out CmdLineArg) is
   begin
      if Number >= Arg_Count or (not Initialized) then
         raise Constraint_Error;
      end if;
      
      declare
         L   : constant Integer := Len_Arg(Number);
         Arg : aliased String(1 .. L);
      begin
         -- Will it fit into the available space?
         if L > Result'Length then
            raise Constraint_Error;
         end if;
         
         -- Get this arg string from where GNAT stowed it
         Fill_Arg(Arg'Address, Number);
         
         -- Copy it to Result:
         Result := (others => ' ');
         Result(Arg'Range) := Arg;
      end;
   end Get_Argument;
   
end CmdLine;