gcc/ada/s-finroo.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                S Y S T E M . F I N A L I Z A T I O N _ R O O T           --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2006, Free Software Foundation, Inc.         --
  10 --                                                                          --
  11 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  12 -- terms of the  GNU General Public License as published  by the Free Soft- --
  13 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  14 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  15 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  16 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNAT;  see file COPYING.  If not, write --
  19 -- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --
  20 -- Boston, MA 02110-1301, USA.                                              --
  21 --                                                                          --
  22 -- As a special exception,  if other files  instantiate  generics from this --
  23 -- unit, or you link  this unit with other files  to produce an executable, --
  24 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  25 -- covered  by the  GNU  General  Public  License.  This exception does not --
  26 -- however invalidate  any other reasons why  the executable file  might be --
  27 -- covered by the  GNU Public License.                                      --
  28 --                                                                          --
  29 -- GNAT was originally developed  by the GNAT team at  New York University. --
  30 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 --  This unit provides the basic support for controlled (finalizable) types
  35
  36 with Ada.Streams;
  37 with Unchecked_Conversion;
  38
  39 package System.Finalization_Root is
  40    pragma Preelaborate;
  41
  42    type Root_Controlled;
  43
  44    type Finalizable_Ptr is access all Root_Controlled'Class;
  45
  46    function To_Finalizable_Ptr is
  47      new Unchecked_Conversion (Address, Finalizable_Ptr);
  48
  49    function To_Addr is
  50      new Unchecked_Conversion (Finalizable_Ptr, Address);
  51
  52    type Empty_Root_Controlled is abstract tagged null record;
  53    --  Just for the sake of Controlled equality (see Ada.Finalization)
  54
  55    type Root_Controlled is new Empty_Root_Controlled with record
  56       Prev, Next : Finalizable_Ptr;
  57    end record;
  58    subtype Finalizable is Root_Controlled'Class;
  59
  60    procedure Initialize (Object : in out Root_Controlled);
  61    procedure Finalize   (Object : in out Root_Controlled);
  62    procedure Adjust     (Object : in out Root_Controlled);
  63
  64    procedure Write
  65      (Stream : not null access Ada.Streams.Root_Stream_Type'Class;
  66       Item   : Root_Controlled);
  67
  68    procedure Read
  69      (Stream : not null access Ada.Streams.Root_Stream_Type'Class;
  70       Item   : out Root_Controlled);
  71
  72    for Root_Controlled'Read use Read;
  73    for Root_Controlled'Write use Write;
  74 end System.Finalization_Root;