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 --                                                                          --
  10 --          Copyright (C) 1992-1998 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 --
  20 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  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 with System.WCh_Con; use System.WCh_Con;
  36
  37 package body System.Wid_WChar is
  38
  39    --------------------------
  40    -- Width_Wide_Character --
  41    --------------------------
  42
  43    function Width_Wide_Character
  44      (Lo, Hi : Wide_Character;
  45       EM     : WC_Encoding_Method)
  46       return   Natural
  47    is
  48       W : Natural;
  49       P : Natural;
  50
  51    begin
  52       W := 0;
  53
  54       for C in Lo .. Hi loop
  55          P := Wide_Character'Pos (C);
  56
  57          --  Here if we find a character in wide character range
  58
  59          if P > 16#FF# then
  60
  61             case EM is
  62
  63                when WCEM_Hex =>
  64                   return Natural'Max (W, 5);
  65
  66                when WCEM_Upper =>
  67                   return Natural'Max (W, 2);
  68
  69                when WCEM_Shift_JIS =>
  70                   return Natural'Max (W, 2);
  71
  72                when WCEM_EUC =>
  73                   return Natural'Max (W, 2);
  74
  75                when WCEM_UTF8 =>
  76                   if Hi > Wide_Character'Val (16#07FF#) then
  77                      return Natural'Max (W, 3);
  78                   else
  79                      return Natural'Max (W, 2);
  80                   end if;
  81
  82                when WCEM_Brackets =>
  83                   return Natural'Max (W, 8);
  84
  85             end case;
  86
  87          --  If we are in character range then use length of character image
  88
  89          else
  90             declare
  91                S : constant String := Character'Image (Character'Val (P));
  92             begin
  93                W := Natural'Max (W, S'Length);
  94             end;
  95          end if;
  96       end loop;
  97
  98       return W;
  99    end Width_Wide_Character;
 100
 101 end System.Wid_WChar;