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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- S Y S T E M . V A L _ D E C --
-- --
-- S p e c --
-- --
-- $Revision: 1.3 $ --
-- --
-- Copyright (C) 1992,1993,1994,1995,1996 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 2, 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. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNAT; see file COPYING. If not, write --
-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
-- MA 02111-1307, USA. --
-- --
-- As a special exception, if other files instantiate generics from this --
-- unit, or you link this unit with other files to produce an executable, --
-- this unit does not by itself cause the resulting executable to be --
-- covered by the GNU General Public License. This exception does not --
-- however invalidate any other reasons why the executable file might be --
-- covered by the GNU Public License. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
-- --
------------------------------------------------------------------------------
-- This package contains routines for scanning decimal values where the size
-- of the type is no greater than Standard.Integer'Size, for use in Text_IO.
-- Decimal_IO, and the Value attribute for such decimal types.
package System.Val_Dec is
pragma Pure (Val_Dec);
function Scan_Decimal
(Str : String;
Ptr : access Integer;
Max : Integer;
Scale : Integer)
return Integer;
-- 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
-- Integer'Integer_Value (decimal-literal-value), using the given Scale
-- 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_Decimal (Str : String; Scale : Integer) return Integer;
-- Used in computing X'Value (Str) where X is a decimal types whose size
-- does not exceed Standard.Integer'Size. 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, otherwise the value returned is the
-- value Integer'Integer_Value (decimal-literal-value), using the given
-- Scale to determine this value.
end System.Val_Dec;
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