File : s-valuti.ads
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-- --
-- GNAT COMPILER COMPONENTS --
-- --
5 -- S Y S T E M . V A L _ U T I L --
-- --
-- S p e c --
-- --
-- $Revision: 1.10 $ --
10 -- --
-- 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- --
15 -- 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 --
20 -- 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 --
25 -- 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. --
30 -- --
-- 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). --
-- --
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35
-- This package provides some common utilities used by the s-valxxx files
package System.Val_Util is
pragma Pure (Val_Util);
40
procedure Normalize_String
(S : in out String;
F, L : out Integer);
-- This procedure scans the string S setting F to be the index of the first
45 -- non-blank character of S and L to be the index of the last non-blank
-- character of S. Any lower case characters present in S will be folded
-- to their upper case equivalent except for character literals. If S
-- consists of entirely blanks then Constraint_Error is raised.
--
50 -- Note: if S is the null string, F is set to S'First, L to S'Last
procedure Scan_Sign
(Str : String;
Ptr : access Integer;
55 Max : Integer;
Minus : out Boolean;
Start : out Positive);
-- The Str, Ptr, Max parameters are as for the scan routines (Str is the
-- string to be scanned starting at Ptr.all, and Max is the index of the
60 -- last character in the string). Scan_Sign first scans out any initial
-- blanks, raising Constraint_Error if the field is all blank. It then
-- checks for and skips an initial plus or minus, requiring a non-blank
-- character to follow (Constraint_Error is raised if plus or minus
-- appears at the end of the string or with a following blank). Minus is
65 -- set True if a minus sign was skipped, and False otherwise. On exit
-- Ptr.all points to the character after the sign, or to the first
-- non-blank character if no sign is present. Start is set to the point
-- to the first non-blank character (sign or digit after it).
--
70 -- 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. Constraint_Error is
-- also raised in this case.
75 function Scan_Exponent
(Str : String;
Ptr : access Integer;
Max : Integer;
Real : Boolean := False)
80 return Integer;
-- Called to scan a possible exponent. Str, Ptr, Max are as described above
-- for Scan_Sign. If Ptr.all < Max and Str (Ptr.all) = 'E' or 'e', then an
-- exponent is scanned out, with the exponent value returned in Exp, and
-- Ptr.all updated to point past the exponent. If the exponent field is
85 -- incorrectly formed or not present, then Ptr.all is unchanged, and the
-- returned exponent value is zero. Real indicates whether a minus sign
-- is permitted (True = permitted). Very large exponents are handled by
-- returning a suitable large value. If the base is zero, then any value
-- is allowed, and otherwise the large value will either cause underflow
90 -- or overflow during the scaling process which is fine.
procedure Scan_Trailing_Blanks (Str : String; P : Positive);
-- Checks that the remainder of the field Str (P .. Str'Last) is all
-- blanks. Raises Constraint_Error if a non-blank character is found.
95
procedure Scan_Underscore
(Str : String;
P : in out Natural;
Ptr : access Integer;
100 Max : Integer;
Ext : Boolean);
-- Called if an underscore is encountered while scanning digits. Str (P)
-- contains the underscore. Ptr it the pointer to be returned to the
-- ultimate caller of the scan routine, Max is the maximum subscript in
105 -- Str, and Ext indicates if extended digits are allowed. In the case
-- where the underscore is invalid, Constraint_Error is raised with Ptr
-- set appropriately, otherwise control returns with P incremented past
-- the underscore.
110 end System.Val_Util;