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------------------------------------------------------------------------------
-- --
-- GNAT COMPILER COMPONENTS --
-- --
-- S Y S T E M . P O O L _ L O C A L --
-- --
-- B o d y --
-- --
-- $Revision: 1.11 $
-- --
-- Copyright (C) 1992-2001, 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 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 --
-- 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 --
-- 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. --
-- --
-- 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). --
-- --
------------------------------------------------------------------------------
with System.Memory;
with System.Storage_Elements;
with System.Address_To_Access_Conversions;
package body System.Pool_Local is
package SSE renames System.Storage_Elements;
use type SSE.Storage_Offset;
Pointer_Size : constant SSE.Storage_Offset := Address'Size / Storage_Unit;
Pointers_Size : constant SSE.Storage_Offset := 2 * Pointer_Size;
type Acc_Address is access all Address;
package Addr is new Address_To_Access_Conversions (Address);
-----------------------
-- Local Subprograms --
-----------------------
function Next (A : Address) return Acc_Address;
-- Given an address of a block, return an access to the next block
function Prev (A : Address) return Acc_Address;
-- Given an address of a block, return an access to the previous block
--------------
-- Allocate --
--------------
procedure Allocate
(Pool : in out Unbounded_Reclaim_Pool;
Address : out System.Address;
Storage_Size : SSE.Storage_Count;
Alignment : SSE.Storage_Count)
is
Allocated : constant System.Address :=
Memory.Alloc (Memory.size_t (Storage_Size + Pointers_Size));
begin
-- The call to Alloc returns an address whose alignment is compatible
-- with the worst case alignment requirement for the machine; thus the
-- Alignment argument can be safely ignored.
if Allocated = Null_Address then
raise Storage_Error;
else
Address := Allocated + Pointers_Size;
Next (Allocated).all := Pool.First;
Prev (Allocated).all := Null_Address;
if Pool.First /= Null_Address then
Prev (Pool.First).all := Allocated;
end if;
Pool.First := Allocated;
end if;
end Allocate;
----------------
-- Deallocate --
----------------
procedure Deallocate
(Pool : in out Unbounded_Reclaim_Pool;
Address : System.Address;
Storage_Size : SSE.Storage_Count;
Alignment : SSE.Storage_Count)
is
Allocated : constant System.Address := Address - Pointers_Size;
begin
if Prev (Allocated).all = Null_Address then
Pool.First := Next (Allocated).all;
Prev (Pool.First).all := Null_Address;
else
Next (Prev (Allocated).all).all := Next (Allocated).all;
end if;
if Next (Allocated).all /= Null_Address then
Prev (Next (Allocated).all).all := Prev (Allocated).all;
end if;
Memory.Free (Allocated);
end Deallocate;
--------------
-- Finalize --
--------------
procedure Finalize (Pool : in out Unbounded_Reclaim_Pool) is
N : System.Address := Pool.First;
Allocated : System.Address;
begin
while N /= Null_Address loop
Allocated := N;
N := Next (N).all;
Memory.Free (Allocated);
end loop;
end Finalize;
----------
-- Next --
----------
function Next (A : Address) return Acc_Address is
begin
return Acc_Address (Addr.To_Pointer (A));
end Next;
----------
-- Prev --
----------
function Prev (A : Address) return Acc_Address is
begin
return Acc_Address (Addr.To_Pointer (A + Pointer_Size));
end Prev;
end System.Pool_Local;