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-- --
-- --
-- S Y S T E M . V A L U E _ I --
-- --
-- S p e c --
-- --
-- Copyright (C) 1992-2021, 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- --
-- ware Foundation; either version 3, 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 --
-- --
-- As a special exception under Section 7 of GPL version 3, you are granted --
-- additional permissions described in the GCC Runtime Library Exception, --
-- version 3.1, as published by the Free Software Foundation. --
-- --
-- You should have received a copy of the GNU General Public License and --
-- a copy of the GCC Runtime Library Exception along with this program; --
-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
-- <>. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- Extensive contributions were provided by Ada Core Technologies Inc. --
-- --
-- This package contains routines for scanning signed integer values for use
-- in Text_IO.Integer_IO, and the Value attribute.
type Int is range <>;
type Uns is mod <>;
with function Scan_Raw_Unsigned
(Str : String;
Ptr : not null access Integer;
Max : Integer) return Uns;
package System.Value_I is
pragma Preelaborate;
function Scan_Integer
(Str : String;
Ptr : not null access Integer;
Max : Integer) return Int;
-- This function scans the string starting at Str (Ptr.all) for a valid
-- integer according to the syntax described in (RM 3.5(43)). The substring
-- scanned extends no further than Str (Max). There are three cases for the
-- return:
-- If a valid integer is found after scanning past any initial spaces, then
-- Ptr.all is updated past the last character of the integer (but trailing
-- spaces are not scanned out).
-- If no valid integer is found, then Ptr.all points either to an initial
-- non-digit character, or to Max + 1 if the field is all spaces and the
-- exception Constraint_Error is raised.
-- If a syntactically valid integer is scanned, but the value is out of
-- range, or, in the based case, the base value is out of range or there
-- is an out of range digit, then Ptr.all points past the integer, and
-- Constraint_Error is raised.
-- Note: these rules correspond to the requirements for leaving the pointer
-- positioned in Text_Io.Get
-- Note: if Str is null, i.e. if Max is less than Ptr, then this is a
-- special case of an all-blank string, and Ptr is unchanged, and hence
-- is greater than Max as required in this case.
function Value_Integer (Str : String) return Int;
-- Used in computing X'Value (Str) where X is a signed integer type whose
-- base range does not exceed the base range of Integer. Str is the string
-- argument of the attribute. Constraint_Error is raised if the string is
-- malformed, or if the value is out of range.
end System.Value_I;