------------------------------------------------------------------------------ -- -- -- GNAT COMPILER COMPONENTS -- -- -- -- S Y S T E M . V A L _ R E A L -- -- -- -- S p e c -- -- -- -- Copyright (C) 1992-2024, 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 -- -- or FITNESS FOR A PARTICULAR PURPOSE. -- -- -- -- 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. generic type Num is digits <>; Maxpow : Positive; Powfive_Address : System.Address; Powfive_100_Address : System.Address; Powfive_200_Address : System.Address; Powfive_300_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;