127 lines
6.8 KiB
Ada
127 lines
6.8 KiB
Ada
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------------------------------------------------------------------------------
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-- --
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-- GNAT COMPILER COMPONENTS --
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-- --
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-- S Y S T E M . V A L _ U T I L --
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-- --
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-- S p e c --
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-- --
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-- Copyright (C) 1992-2014, Free Software Foundation, Inc. --
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-- --
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-- GNAT is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 3, or (at your option) any later ver- --
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-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. --
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-- --
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-- As a special exception under Section 7 of GPL version 3, you are granted --
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-- additional permissions described in the GCC Runtime Library Exception, --
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-- version 3.1, as published by the Free Software Foundation. --
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-- --
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-- You should have received a copy of the GNU General Public License and --
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-- a copy of the GCC Runtime Library Exception along with this program; --
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-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
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-- <http://www.gnu.org/licenses/>. --
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-- --
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-- GNAT was originally developed by the GNAT team at New York University. --
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-- Extensive contributions were provided by Ada Core Technologies Inc. --
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-- --
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------------------------------------------------------------------------------
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-- This package provides some common utilities used by the s-valxxx files
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package System.Val_Util is
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pragma Pure;
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procedure Bad_Value (S : String);
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pragma No_Return (Bad_Value);
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-- Raises constraint error with message: bad input for 'Value: "xxx"
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procedure Normalize_String
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(S : in out String;
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F, L : out Integer);
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-- This procedure scans the string S setting F to be the index of the first
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-- non-blank character of S and L to be the index of the last non-blank
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-- character of S. Any lower case characters present in S will be folded to
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-- their upper case equivalent except for character literals. If S consists
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-- of entirely blanks then Constraint_Error is raised.
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--
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-- Note: if S is the null string, F is set to S'First, L to S'Last
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procedure Scan_Sign
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(Str : String;
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Ptr : not null access Integer;
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Max : Integer;
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Minus : out Boolean;
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Start : out Positive);
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-- The Str, Ptr, Max parameters are as for the scan routines (Str is the
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-- string to be scanned starting at Ptr.all, and Max is the index of the
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-- last character in the string). Scan_Sign first scans out any initial
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-- blanks, raising Constraint_Error if the field is all blank. It then
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-- checks for and skips an initial plus or minus, requiring a non-blank
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-- character to follow (Constraint_Error is raised if plus or minus appears
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-- at the end of the string or with a following blank). Minus is set True
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-- if a minus sign was skipped, and False otherwise. On exit Ptr.all points
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-- to the character after the sign, or to the first non-blank character
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-- if no sign is present. Start is set to the point to the first non-blank
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-- character (sign or digit after it).
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--
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-- Note: if Str is null, i.e. if Max is less than Ptr, then this is a
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-- special case of an all-blank string, and Ptr is unchanged, and hence
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-- is greater than Max as required in this case. Constraint_Error is also
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-- raised in this case.
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--
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-- This routine must not be called with Str'Last = Positive'Last. There is
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-- no check for this case, the caller must ensure this condition is met.
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procedure Scan_Plus_Sign
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(Str : String;
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Ptr : not null access Integer;
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Max : Integer;
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Start : out Positive);
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-- Same as Scan_Sign, but allows only plus, not minus. This is used for
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-- modular types.
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function Scan_Exponent
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(Str : String;
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Ptr : not null access Integer;
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Max : Integer;
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Real : Boolean := False) return Integer;
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-- Called to scan a possible exponent. Str, Ptr, Max are as described above
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-- for Scan_Sign. If Ptr.all < Max and Str (Ptr.all) = 'E' or 'e', then an
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-- exponent is scanned out, with the exponent value returned in Exp, and
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-- Ptr.all updated to point past the exponent. If the exponent field is
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-- incorrectly formed or not present, then Ptr.all is unchanged, and the
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-- returned exponent value is zero. Real indicates whether a minus sign
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-- is permitted (True = permitted). Very large exponents are handled by
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-- returning a suitable large value. If the base is zero, then any value
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-- is allowed, and otherwise the large value will either cause underflow
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-- or overflow during the scaling process which is fine.
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--
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-- This routine must not be called with Str'Last = Positive'Last. There is
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-- no check for this case, the caller must ensure this condition is met.
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procedure Scan_Trailing_Blanks (Str : String; P : Positive);
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-- Checks that the remainder of the field Str (P .. Str'Last) is all
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-- blanks. Raises Constraint_Error if a non-blank character is found.
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procedure Scan_Underscore
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(Str : String;
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P : in out Natural;
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Ptr : not null access Integer;
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Max : Integer;
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Ext : Boolean);
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-- Called if an underscore is encountered while scanning digits. Str (P)
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-- contains the underscore. Ptr it the pointer to be returned to the
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-- ultimate caller of the scan routine, Max is the maximum subscript in
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-- Str, and Ext indicates if extended digits are allowed. In the case
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-- where the underscore is invalid, Constraint_Error is raised with Ptr
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-- set appropriately, otherwise control returns with P incremented past
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-- the underscore.
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--
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-- This routine must not be called with Str'Last = Positive'Last. There is
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-- no check for this case, the caller must ensure this condition is met.
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end System.Val_Util;
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