gcc/ada/s-widwch.adb

   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
  34 with System.WCh_Con; use System.WCh_Con;
  35
  36 package 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
 100 end System.Wid_WChar;