1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--                       S Y S T E M . V A L _ I N T                        --
6--                                                                          --
7--                                 B o d y                                  --
8--                                                                          --
9--          Copyright (C) 1992-2012, 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
32with System.Unsigned_Types; use System.Unsigned_Types;
33with System.Val_Uns;        use System.Val_Uns;
34with System.Val_Util;       use System.Val_Util;
35
36package body System.Val_Int is
37
38   ------------------
39   -- Scan_Integer --
40   ------------------
41
42   function Scan_Integer
43     (Str : String;
44      Ptr : not null access Integer;
45      Max : Integer) return Integer
46   is
47      Uval : Unsigned;
48      --  Unsigned result
49
50      Minus : Boolean := False;
51      --  Set to True if minus sign is present, otherwise to False
52
53      Start : Positive;
54      --  Saves location of first non-blank (not used in this case)
55
56   begin
57      Scan_Sign (Str, Ptr, Max, Minus, Start);
58
59      if Str (Ptr.all) not in '0' .. '9' then
60         Ptr.all := Start;
61         Bad_Value (Str);
62      end if;
63
64      Uval := Scan_Raw_Unsigned (Str, Ptr, Max);
65
66      --  Deal with overflow cases, and also with maximum negative number
67
68      if Uval > Unsigned (Integer'Last) then
69         if Minus and then Uval = Unsigned (-(Integer'First)) then
70            return Integer'First;
71         else
72            Bad_Value (Str);
73         end if;
74
75      --  Negative values
76
77      elsif Minus then
78         return -(Integer (Uval));
79
80      --  Positive values
81
82      else
83         return Integer (Uval);
84      end if;
85   end Scan_Integer;
86
87   -------------------
88   -- Value_Integer --
89   -------------------
90
91   function Value_Integer (Str : String) return Integer is
92      V : Integer;
93      P : aliased Integer := Str'First;
94   begin
95      V := Scan_Integer (Str, P'Access, Str'Last);
96      Scan_Trailing_Blanks (Str, P);
97      return V;
98   end Value_Integer;
99
100end System.Val_Int;
101