86 lines
4.2 KiB
Ada
86 lines
4.2 KiB
Ada
------------------------------------------------------------------------------
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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 . F I N A L I Z A T I O N _ R O O T --
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-- --
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-- S p e c --
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-- --
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-- Copyright (C) 1992-2009, 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 unit provides the basic support for controlled (finalizable) types
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with Ada.Streams;
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with Ada.Unchecked_Conversion;
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package System.Finalization_Root is
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pragma Preelaborate;
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type Root_Controlled is tagged;
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type Finalizable_Ptr is access all Root_Controlled'Class;
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function To_Finalizable_Ptr is
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new Ada.Unchecked_Conversion (Address, Finalizable_Ptr);
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function To_Addr is
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new Ada.Unchecked_Conversion (Finalizable_Ptr, Address);
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type Empty_Root_Controlled is abstract tagged null record;
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-- Just for the sake of Controlled equality (see Ada.Finalization)
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type Root_Controlled is new Empty_Root_Controlled with record
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Prev, Next : Finalizable_Ptr;
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end record;
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subtype Finalizable is Root_Controlled'Class;
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procedure Initialize (Object : in out Root_Controlled);
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procedure Finalize (Object : in out Root_Controlled);
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procedure Adjust (Object : in out Root_Controlled);
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-- Stream-oriented attributes for Root_Controlled. These must be empty so
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-- as to not copy the finalization chain pointers. They are declared in
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-- a nested package so that they do not create primitive operations of
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-- Root_Controlled. Otherwise this would add unwanted primitives to (the
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-- full view of) Ada.Finalization.Limited_Controlled, which would cause
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-- trouble in cases where a limited controlled type is used as the
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-- designated type of a remote access-to-classwide type.
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package Stream_Attributes is
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procedure Write
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(Stream : not null access Ada.Streams.Root_Stream_Type'Class;
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Item : Root_Controlled) is null;
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procedure Read
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(Stream : not null access Ada.Streams.Root_Stream_Type'Class;
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Item : out Root_Controlled) is null;
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end Stream_Attributes;
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for Root_Controlled'Read use Stream_Attributes.Read;
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for Root_Controlled'Write use Stream_Attributes.Write;
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end System.Finalization_Root;
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