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 --                                                                          --
  10 --          Copyright (C) 1992-2000, Free Software Foundation, Inc.         --
  11 --                                                                          --
  12 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  13 -- terms of the  GNU General Public License as published  by the Free Soft- --
  14 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  15 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  16 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  17 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  18 -- for  more details.  You should have  received  a copy of the GNU General --
  19 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
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  21 -- MA 02111-1307, USA.                                                      --
  22 --                                                                          --
  23 -- As a special exception,  if other files  instantiate  generics from this --
  24 -- unit, or you link  this unit with other files  to produce an executable, --
  25 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  26 -- covered  by the  GNU  General  Public  License.  This exception does not --
  27 -- however invalidate  any other reasons why  the executable file  might be --
  28 -- covered by the  GNU Public License.                                      --
  29 --                                                                          --
  30 -- GNAT was originally developed  by the GNAT team at  New York University. --
  31 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  32 --                                                                          --
  33 ------------------------------------------------------------------------------
  34
  35 package body System.Wwd_WChar is
  36
  37    -------------------------------
  38    -- Wide_Width_Wide_Character --
  39    -------------------------------
  40
  41    function Wide_Width_Wide_Character
  42      (Lo, Hi : Wide_Character)
  43       return   Natural
  44    is
  45       W : Natural;
  46       P : Natural;
  47
  48    begin
  49       W := 0;
  50
  51       for C in Lo .. Hi loop
  52          P := Wide_Character'Pos (C);
  53
  54          --  If we are in wide character range, the length is always 3
  55          --  and we are done, since all remaining characters are the same.
  56
  57          if P > 255 then
  58             return Natural'Max (W, 3);
  59
  60          --  If we are in character range then use length of character image
  61          --  Is this right, what about wide char encodings of 80-FF???
  62
  63          else
  64             declare
  65                S : Wide_String := 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;