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------------------------------------------------------------------------------
-- --
-- GNAT RUNTIME COMPONENTS --
-- --
-- S Y S T E M . V A L _ I N T --
-- --
-- S p e c --
-- --
-- --
-- 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. --
-- 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.
package System.Val_Int is
pragma Pure (Val_Int);
function Scan_Integer
(Str : String;
Ptr : access Integer;
Max : Integer)
return Integer;
-- 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 Integer;
-- 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.Val_Int;
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