File : s-valint.adb
------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
5 -- S Y S T E M . V A L _ I N T --
-- --
-- B o d y --
-- --
-- $Revision: 1.9 $ --
10 -- --
-- Copyright (C) 1992,1993,1994,1995,1996 Free Software Foundation, Inc. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
15 -- ware Foundation; either version 2, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
20 -- Public License distributed with GNAT; see file COPYING. If not, write --
-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
-- MA 02111-1307, USA. --
-- --
-- As a special exception, if other files instantiate generics from this --
25 -- unit, or you link this unit with other files to produce an executable, --
-- this unit does not by itself cause the resulting executable to be --
-- covered by the GNU General Public License. This exception does not --
-- however invalidate any other reasons why the executable file might be --
-- covered by the GNU Public License. --
30 -- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
-- --
------------------------------------------------------------------------------
35
with System.Unsigned_Types; use System.Unsigned_Types;
with System.Val_Uns; use System.Val_Uns;
with System.Val_Util; use System.Val_Util;
40 package body System.Val_Int is
------------------
-- Scan_Integer --
------------------
45
function Scan_Integer
(Str : String;
Ptr : access Integer;
Max : Integer)
50 return Integer
is
Uval : Unsigned;
-- Unsigned result
55 Minus : Boolean := False;
-- Set to True if minus sign is present, otherwise to False
Start : Positive;
-- Saves location of first non-blank (not used in this case)
60
begin
Scan_Sign (Str, Ptr, Max, Minus, Start);
Uval := Scan_Unsigned (Str, Ptr, Max);
65 -- Deal with overflow cases, and also with maximum negative number
if Uval > Unsigned (Integer'Last) then
if Minus and then Uval = Unsigned (-(Integer'First)) then
return Integer'First;
70 else
raise Constraint_Error;
end if;
-- Negative values
75
elsif Minus then
return -(Integer (Uval));
-- Positive values
80
else
return Integer (Uval);
end if;
85 end Scan_Integer;
-------------------
-- Value_Integer --
-------------------
90
function Value_Integer (Str : String) return Integer is
V : Integer;
P : aliased Integer := Str'First;
95 begin
V := Scan_Integer (Str, P'Access, Str'Last);
Scan_Trailing_Blanks (Str, P);
return V;
end Value_Integer;
100
end System.Val_Int;