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-- --
-- --
-- S Y S T E M . V A L _ R E A L --
-- --
-- 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 real values for use in
-- Text_IO.Float_IO and the Value attribute.
type Num is digits <>;
Maxpow : Positive;
Powten_Address : System.Address;
type Uns is mod <>;
package System.Val_Real is
pragma Preelaborate;
function Scan_Real
(Str : String;
Ptr : not null access Integer;
Max : Integer) return Num;
-- This function scans the string starting at Str (Ptr.all) for a valid
-- real literal 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 real is found after scanning past any initial spaces, then
-- Ptr.all is updated past the last character of the real (but trailing
-- spaces are not scanned out).
-- If no valid real is found, then Ptr.all points either to an initial
-- non-blank character, or to Max + 1 if the field is all spaces and the
-- exception Constraint_Error is raised.
-- If a syntactically valid real 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 real literal,
-- 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.
-- Note: this routine should not be called with Str'Last = Positive'Last.
-- If this occurs Program_Error is raised with a message noting that this
-- case is not supported. Most such cases are eliminated by the caller.
function Value_Real (Str : String) return Num;
-- Used in computing X'Value (Str) where X is a floating-point type or an
-- ordinary fixed-point type. Str is the string argument of the attribute.
-- Constraint_Error is raised if the string is malformed, or if the value
-- out of range of Num.
end System.Val_Real;