gcc/ada/switch.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                               S W I T C H                                --
   6 --                                                                          --
   7 --                                 B o d y                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2004, 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,  51  Franklin  Street,  Fifth  Floor, --
  20 -- Boston, MA 02110-1301, USA.                                              --
  21 --                                                                          --
  22 -- GNAT was originally developed  by the GNAT team at  New York University. --
  23 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  24 --                                                                          --
  25 ------------------------------------------------------------------------------
  26
  27 package body Switch is
  28
  29    -------------------------
  30    -- Is_Front_End_Switch --
  31    -------------------------
  32
  33    function Is_Front_End_Switch (Switch_Chars : String) return Boolean is
  34       Ptr : constant Positive := Switch_Chars'First;
  35    begin
  36       return Is_Switch (Switch_Chars)
  37         and then
  38           (Switch_Chars (Ptr + 1) = 'I'
  39             or else (Switch_Chars'Length >= 5
  40                       and then Switch_Chars (Ptr + 1 .. Ptr + 4) = "gnat")
  41             or else (Switch_Chars'Length >= 5
  42                       and then Switch_Chars (Ptr + 2 .. Ptr + 4) = "RTS"));
  43    end Is_Front_End_Switch;
  44
  45    ---------------
  46    -- Is_Switch --
  47    ---------------
  48
  49    function Is_Switch (Switch_Chars : String) return Boolean is
  50    begin
  51       return Switch_Chars'Length > 1
  52         and then Switch_Chars (Switch_Chars'First) = '-';
  53    end Is_Switch;
  54
  55    ------------------------
  56    --------------
  57    -- Scan_Nat --
  58    --------------
  59
  60    procedure Scan_Nat
  61      (Switch_Chars : String;
  62       Max          : Integer;
  63       Ptr          : in out Integer;
  64       Result       : out Nat)
  65    is
  66    begin
  67       Result := 0;
  68
  69       if Ptr > Max or else Switch_Chars (Ptr) not in '0' .. '9' then
  70          raise Missing_Switch_Value;
  71       end if;
  72
  73       while Ptr <= Max and then Switch_Chars (Ptr) in '0' .. '9' loop
  74          Result := Result * 10 +
  75            Character'Pos (Switch_Chars (Ptr)) - Character'Pos ('0');
  76          Ptr := Ptr + 1;
  77
  78          if Result > Switch_Max_Value then
  79             raise Bad_Switch_Value;
  80          end if;
  81       end loop;
  82    end Scan_Nat;
  83
  84    --------------
  85    -- Scan_Pos --
  86    --------------
  87
  88    procedure Scan_Pos
  89      (Switch_Chars : String;
  90       Max          : Integer;
  91       Ptr          : in out Integer;
  92       Result       : out Pos)
  93    is
  94       Temp : Nat;
  95
  96    begin
  97       Scan_Nat (Switch_Chars, Max, Ptr, Temp);
  98
  99       if Temp = 0 then
 100          raise Bad_Switch_Value;
 101       end if;
 102
 103       Result := Temp;
 104    end Scan_Pos;
 105
 106 end Switch;