1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT RUNTIME COMPONENTS                          --
4--                                                                          --
5--                     S Y S T E M . W I D _ W C H A R                      --
6--                                                                          --
7--                                 B o d y                                  --
8--                                                                          --
9--          Copyright (C) 1992-1998 Free Software Foundation, Inc.          --
10--                                                                          --
11-- GNAT is free software;  you can  redistribute it  and/or modify it under --
12-- terms of the  GNU General Public License as published  by the Free Soft- --
13-- ware  Foundation;  either version 2,  or (at your option) any later ver- --
14-- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
15-- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
16-- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
17-- for  more details.  You should have  received  a copy of the GNU General --
18-- Public License  distributed with GNAT;  see file COPYING.  If not, write --
19-- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
20-- MA 02111-1307, USA.                                                      --
21--                                                                          --
22-- As a special exception,  if other files  instantiate  generics from this --
23-- unit, or you link  this unit with other files  to produce an executable, --
24-- this  unit  does not  by itself cause  the resulting  executable  to  be --
25-- covered  by the  GNU  General  Public  License.  This exception does not --
26-- however invalidate  any other reasons why  the executable file  might be --
27-- covered by the  GNU Public License.                                      --
28--                                                                          --
29-- GNAT was originally developed  by the GNAT team at  New York University. --
30-- Extensive contributions were provided by Ada Core Technologies Inc.      --
31--                                                                          --
32------------------------------------------------------------------------------
33
34with System.WCh_Con; use System.WCh_Con;
35
36package body System.Wid_WChar is
37
38   --------------------------
39   -- Width_Wide_Character --
40   --------------------------
41
42   function Width_Wide_Character
43     (Lo, Hi : Wide_Character;
44      EM     : WC_Encoding_Method)
45      return   Natural
46   is
47      W : Natural;
48      P : Natural;
49
50   begin
51      W := 0;
52
53      for C in Lo .. Hi loop
54         P := Wide_Character'Pos (C);
55
56         --  Here if we find a character in wide character range
57
58         if P > 16#FF# then
59
60            case EM is
61
62               when WCEM_Hex =>
63                  return Natural'Max (W, 5);
64
65               when WCEM_Upper =>
66                  return Natural'Max (W, 2);
67
68               when WCEM_Shift_JIS =>
69                  return Natural'Max (W, 2);
70
71               when WCEM_EUC =>
72                  return Natural'Max (W, 2);
73
74               when WCEM_UTF8 =>
75                  if Hi > Wide_Character'Val (16#07FF#) then
76                     return Natural'Max (W, 3);
77                  else
78                     return Natural'Max (W, 2);
79                  end if;
80
81               when WCEM_Brackets =>
82                  return Natural'Max (W, 8);
83
84            end case;
85
86         --  If we are in character range then use length of character image
87
88         else
89            declare
90               S : constant String := Character'Image (Character'Val (P));
91            begin
92               W := Natural'Max (W, S'Length);
93            end;
94         end if;
95      end loop;
96
97      return W;
98   end Width_Wide_Character;
99
100end System.Wid_WChar;
101