gcc/ada/s-valcha.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                      S Y S T E M . V A L _ C H A R                       --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2010, 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 3,  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.                                     --
  17 --                                                                          --
  18 -- As a special exception under Section 7 of GPL version 3, you are granted --
  19 -- additional permissions described in the GCC Runtime Library Exception,   --
  20 -- version 3.1, as published by the Free Software Foundation.               --
  21 --                                                                          --
  22 -- You should have received a copy of the GNU General Public License and    --
  23 -- a copy of the GCC Runtime Library Exception along with this program;     --
  24 -- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
  25 -- <http://www.gnu.org/licenses/>.                                          --
  26 --                                                                          --
  27 -- GNAT was originally developed  by the GNAT team at  New York University. --
  28 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  29 --                                                                          --
  30 ------------------------------------------------------------------------------
  31
  32 with System.Val_Util; use System.Val_Util;
  33
  34 package body System.Val_Char is
  35
  36    ---------------------
  37    -- Value_Character --
  38    ---------------------
  39
  40    function Value_Character (Str : String) return Character is
  41       F : Natural;
  42       L : Natural;
  43       S : String (Str'Range) := Str;
  44
  45    begin
  46       Normalize_String (S, F, L);
  47
  48       --  Accept any single character enclosed in quotes
  49
  50       if L - F = 2 and then S (F) = ''' and then S (L) = ''' then
  51          return Character'Val (Character'Pos (S (F + 1)));
  52
  53       --  Check control character cases
  54
  55       else
  56          for C in Character'Val (16#00#) .. Character'Val (16#1F#) loop
  57             if S (F .. L) = Character'Image (C) then
  58                return C;
  59             end if;
  60          end loop;
  61
  62          for C in Character'Val (16#7F#) .. Character'Val (16#9F#) loop
  63             if S (F .. L) = Character'Image (C) then
  64                return C;
  65             end if;
  66          end loop;
  67
  68          if S (F .. L) = "SOFT_HYPHEN" then
  69             return Character'Val (16#AD#);
  70          end if;
  71
  72          raise Constraint_Error;
  73       end if;
  74    end Value_Character;
  75
  76 end System.Val_Char;