119 lines
4.5 KiB
Ada
119 lines
4.5 KiB
Ada
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------------------------------------------------------------------------------
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-- --
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-- GNAT COMPILER COMPONENTS --
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-- --
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-- S Y S T E M . V A L _ I N T --
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-- --
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-- B o d y --
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-- --
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-- Copyright (C) 1992-2014, Free Software Foundation, Inc. --
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-- --
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-- GNAT is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 3, or (at your option) any later ver- --
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-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. --
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-- --
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-- As a special exception under Section 7 of GPL version 3, you are granted --
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-- additional permissions described in the GCC Runtime Library Exception, --
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-- version 3.1, as published by the Free Software Foundation. --
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-- --
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-- You should have received a copy of the GNU General Public License and --
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-- a copy of the GCC Runtime Library Exception along with this program; --
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-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
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-- <http://www.gnu.org/licenses/>. --
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-- --
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-- GNAT was originally developed by the GNAT team at New York University. --
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-- Extensive contributions were provided by Ada Core Technologies Inc. --
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-- --
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------------------------------------------------------------------------------
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with System.Unsigned_Types; use System.Unsigned_Types;
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with System.Val_Uns; use System.Val_Uns;
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with System.Val_Util; use System.Val_Util;
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package body System.Val_Int is
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------------------
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-- Scan_Integer --
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------------------
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function Scan_Integer
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(Str : String;
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Ptr : not null access Integer;
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Max : Integer) return Integer
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is
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Uval : Unsigned;
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-- Unsigned result
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Minus : Boolean := False;
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-- Set to True if minus sign is present, otherwise to False
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Start : Positive;
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-- Saves location of first non-blank (not used in this case)
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begin
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Scan_Sign (Str, Ptr, Max, Minus, Start);
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if Str (Ptr.all) not in '0' .. '9' then
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Ptr.all := Start;
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Bad_Value (Str);
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end if;
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Uval := Scan_Raw_Unsigned (Str, Ptr, Max);
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-- Deal with overflow cases, and also with maximum negative number
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if Uval > Unsigned (Integer'Last) then
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if Minus and then Uval = Unsigned (-(Integer'First)) then
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return Integer'First;
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else
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Bad_Value (Str);
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end if;
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-- Negative values
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elsif Minus then
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return -(Integer (Uval));
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-- Positive values
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else
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return Integer (Uval);
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end if;
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end Scan_Integer;
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-------------------
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-- Value_Integer --
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-------------------
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function Value_Integer (Str : String) return Integer is
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begin
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-- We have to special case Str'Last = Positive'Last because the normal
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-- circuit ends up setting P to Str'Last + 1 which is out of bounds. We
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-- deal with this by converting to a subtype which fixes the bounds.
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if Str'Last = Positive'Last then
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declare
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subtype NT is String (1 .. Str'Length);
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begin
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return Value_Integer (NT (Str));
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end;
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-- Normal case where Str'Last < Positive'Last
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else
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declare
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V : Integer;
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P : aliased Integer := Str'First;
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begin
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V := Scan_Integer (Str, P'Access, Str'Last);
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Scan_Trailing_Blanks (Str, P);
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return V;
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end;
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end if;
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end Value_Integer;
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end System.Val_Int;
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