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) 1992-2005 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) return Natural
  45    is
  46       W : Natural;
  47       P : Natural;
  48
  49    begin
  50       W := 0;
  51       for C in Lo .. Hi loop
  52          P := Wide_Character'Pos (C);
  53
  54          --  Here if we find a character in wide character range
  55
  56          if P > 16#FF# then
  57
  58             case EM is
  59
  60                when WCEM_Hex =>
  61                   return Natural'Max (W, 5);
  62
  63                when WCEM_Upper =>
  64                   return Natural'Max (W, 2);
  65
  66                when WCEM_Shift_JIS =>
  67                   return Natural'Max (W, 2);
  68
  69                when WCEM_EUC =>
  70                   return Natural'Max (W, 2);
  71
  72                when WCEM_UTF8 =>
  73                   if Hi > Wide_Character'Val (16#07FF#) then
  74                      return Natural'Max (W, 3);
  75                   else
  76                      return Natural'Max (W, 2);
  77                   end if;
  78
  79                when WCEM_Brackets =>
  80                   return Natural'Max (W, 8);
  81
  82             end case;
  83
  84          --  If we are in character range then use length of character image
  85
  86          else
  87             declare
  88                S : constant String := Character'Image (Character'Val (P));
  89             begin
  90                W := Natural'Max (W, S'Length);
  91             end;
  92          end if;
  93       end loop;
  94
  95       return W;
  96    end Width_Wide_Character;
  97
  98    -------------------------------
  99    -- Width_Wide_Wide_Character --
 100    -------------------------------
 101
 102    function Width_Wide_Wide_Character
 103      (Lo, Hi : Wide_Wide_Character;
 104       EM     : WC_Encoding_Method) return Natural
 105    is
 106       W : Natural;
 107       P : Natural;
 108
 109    begin
 110       W := 0;
 111       for C in Lo .. Hi loop
 112          P := Wide_Wide_Character'Pos (C);
 113
 114          --  Here if we find a character in wide wide character range
 115
 116          if P > 16#FF# then
 117             case EM is
 118                when WCEM_Hex =>
 119                   return Natural'Max (W, 5);
 120
 121                when WCEM_Upper =>
 122                   return Natural'Max (W, 2);
 123
 124                when WCEM_Shift_JIS =>
 125                   return Natural'Max (W, 2);
 126
 127                when WCEM_EUC =>
 128                   return Natural'Max (W, 2);
 129
 130                when WCEM_UTF8 =>
 131                   if Hi > Wide_Wide_Character'Val (16#FFFF#) then
 132                      return Natural'Max (W, 4);
 133                   elsif Hi > Wide_Wide_Character'Val (16#07FF#) then
 134                      return Natural'Max (W, 3);
 135                   else
 136                      return Natural'Max (W, 2);
 137                   end if;
 138
 139                when WCEM_Brackets =>
 140                   return Natural'Max (W, 10);
 141
 142             end case;
 143
 144          --  If we are in character range then use length of character image
 145
 146          else
 147             declare
 148                S : constant String := Character'Image (Character'Val (P));
 149             begin
 150                W := Natural'Max (W, S'Length);
 151             end;
 152          end if;
 153       end loop;
 154
 155       return W;
 156    end Width_Wide_Wide_Character;
 157
 158 end System.Wid_WChar;