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--                                                                          --

--                         GNAT COMPILER COMPONENTS                         --

--                                                                          --

--                      S Y S T E M . V A L _ U T I L                       --

--                                                                          --

--                                 S p e c                                  --

--                                                                          --

--          Copyright (C) 1992-2009, 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    --

-- <http://www.gnu.org/licenses/>.                                          --

--                                                                          --

-- GNAT was originally developed  by the GNAT team at  New York University. --

-- Extensive contributions were provided by Ada Core Technologies Inc.      --

--                                                                          --

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--  This package provides some common utilities used by the s-valxxx files

package System.Val_Util is

   pragma Pure;

   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

   --  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.

   --

   --  Note: if S is the null string, F is set to S'First, L to S'Last

   procedure Scan_Sign

     (Str   : String;

      Ptr   : not null access Integer;

      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

   --  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

   --  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).

   --

   --  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.

   procedure Scan_Plus_Sign

     (Str   : String;

      Ptr   : not null access Integer;

      Max   : Integer;

      Start : out Positive);

   --  Same as Scan_Sign, but allows only plus, not minus.

   --  This is used for modular types.

   function Scan_Exponent

     (Str  : String;

      Ptr  : not null access Integer;

      Max  : Integer;

      Real : Boolean := False) 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

   --  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

   --  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.

   procedure Scan_Underscore

     (Str : String;

      P   : in out Natural;

      Ptr : not null access Integer;

      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

   --  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.

end System.Val_Util;