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-- --
-- --
-- S Y S T E M . V A L U E _ F --
-- --
-- S p e c --
-- --
-- Copyright (C) 2020-2021, 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 the routines for supporting the Value attribute for
-- ordinary fixed point types whose Small is the ratio of two Int values, and
-- also for conversion operations required in Text_IO.Fixed_IO for such types.
type Int is range <>;
type Uns is mod <>;
with procedure Scaled_Divide
(X, Y, Z : Int;
Q, R : out Int;
Round : Boolean);
package System.Value_F is
pragma Preelaborate;
function Scan_Fixed
(Str : String;
Ptr : not null access Integer;
Max : Integer;
Num : Int;
Den : Int) return Int;
-- 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 literal is found after scanning past any initial spaces,
-- then Ptr.all is updated past the last character of the literal (but
-- trailing spaces are not scanned out). The value returned is the value
-- Int'Integer_Value (decimal-literal-value), using the given Num/Den to
-- determine this value.
-- If no valid real literal 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_Fixed
(Str : String;
Num : Int;
Den : Int) return Int;
-- Used in computing X'Value (Str) where X is 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 is out of range of Int (not
-- the range of the fixed-point type, which must be done by the caller).
-- Otherwise the value returned is the value Int'Integer_Value
-- (decimal-literal-value), using Small Num/Den to determine this value.
end System.Value_F;