gcc/ada/s-wwdwch.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUNTIME COMPONENTS                          --
   4 --                                                                          --
   5 --                     S Y S T E M . W W D _ W C H A R                      --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2002, 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
  34 package body System.Wwd_WChar is
  35
  36    -------------------------------
  37    -- Wide_Width_Wide_Character --
  38    -------------------------------
  39
  40    function Wide_Width_Wide_Character
  41      (Lo, Hi : Wide_Character)
  42       return   Natural
  43    is
  44       W : Natural;
  45       P : Natural;
  46
  47    begin
  48       W := 0;
  49
  50       for C in Lo .. Hi loop
  51          P := Wide_Character'Pos (C);
  52
  53          --  If we are in wide character range, the length is always 3
  54          --  and we are done, since all remaining characters are the same.
  55
  56          if P > 255 then
  57             return Natural'Max (W, 3);
  58
  59          --  If we are in character range then use length of character image
  60          --  Is this right, what about wide char encodings of 80-FF???
  61
  62          else
  63             declare
  64                S : constant Wide_String :=
  65                      Character'Wide_Image (Character'Val (P));
  66
  67             begin
  68                W := Natural'Max (W, S'Length);
  69             end;
  70          end if;
  71       end loop;
  72
  73       return W;
  74    end Wide_Width_Wide_Character;
  75
  76 end System.Wwd_WChar;