s-widwch.adb   [plain text]


------------------------------------------------------------------------------
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------------------------------------------------------------------------------

with System.WCh_Con; use System.WCh_Con;

package body System.Wid_WChar is

   --------------------------
   -- Width_Wide_Character --
   --------------------------

   function Width_Wide_Character
     (Lo, Hi : Wide_Character;
      EM     : WC_Encoding_Method)
      return   Natural
   is
      W : Natural;
      P : Natural;

   begin
      W := 0;

      for C in Lo .. Hi loop
         P := Wide_Character'Pos (C);

         --  Here if we find a character in wide character range

         if P > 16#FF# then

            case EM is

               when WCEM_Hex =>
                  return Natural'Max (W, 5);

               when WCEM_Upper =>
                  return Natural'Max (W, 2);

               when WCEM_Shift_JIS =>
                  return Natural'Max (W, 2);

               when WCEM_EUC =>
                  return Natural'Max (W, 2);

               when WCEM_UTF8 =>
                  if Hi > Wide_Character'Val (16#07FF#) then
                     return Natural'Max (W, 3);
                  else
                     return Natural'Max (W, 2);
                  end if;

               when WCEM_Brackets =>
                  return Natural'Max (W, 8);

            end case;

         --  If we are in character range then use length of character image

         else
            declare
               S : constant String := Character'Image (Character'Val (P));
            begin
               W := Natural'Max (W, S'Length);
            end;
         end if;
      end loop;

      return W;
   end Width_Wide_Character;

end System.Wid_WChar;