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 --                            $Revision: 1.4 $
  10 --                                                                          --
  11 --          Copyright (C) 1992-2000, Free Software Foundation, Inc.         --
  12 --                                                                          --
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  14 -- terms of the  GNU General Public License as published  by the Free Soft- --
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  19 -- for  more details.  You should have  received  a copy of the GNU General --
  20 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
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  22 -- MA 02111-1307, USA.                                                      --
  23 --                                                                          --
  24 -- As a special exception,  if other files  instantiate  generics from this --
  25 -- unit, or you link  this unit with other files  to produce an executable, --
  26 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  27 -- covered  by the  GNU  General  Public  License.  This exception does not --
  28 -- however invalidate  any other reasons why  the executable file  might be --
  29 -- covered by the  GNU Public License.                                      --
  30 --                                                                          --
  31 -- GNAT was originally developed  by the GNAT team at  New York University. --
  32 -- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
  33 --                                                                          --
  34 ------------------------------------------------------------------------------
  35
  36 package body System.Wwd_WChar is
  37
  38    -------------------------------
  39    -- Wide_Width_Wide_Character --
  40    -------------------------------
  41
  42    function Wide_Width_Wide_Character
  43      (Lo, Hi : Wide_Character)
  44       return   Natural
  45    is
  46       W : Natural;
  47       P : Natural;
  48
  49    begin
  50       W := 0;
  51
  52       for C in Lo .. Hi loop
  53          P := Wide_Character'Pos (C);
  54
  55          --  If we are in wide character range, the length is always 3
  56          --  and we are done, since all remaining characters are the same.
  57
  58          if P > 255 then
  59             return Natural'Max (W, 3);
  60
  61          --  If we are in character range then use length of character image
  62          --  Is this right, what about wide char encodings of 80-FF???
  63
  64          else
  65             declare
  66                S : Wide_String := Character'Wide_Image (Character'Val (P));
  67
  68             begin
  69                W := Natural'Max (W, S'Length);
  70             end;
  71          end if;
  72       end loop;
  73
  74       return W;
  75    end Wide_Width_Wide_Character;
  76
  77 end System.Wwd_WChar;