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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 --
-- --
-- Copyright (C) 1992-2018, 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. --
-- --
------------------------------------------------------------------------------
with System.Memory;
with Ada.Unchecked_Conversion;
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;
function To_Acc_Address is
new Ada.Unchecked_Conversion (Address, Acc_Address);
-----------------------
-- Local Subprograms --
-----------------------
function Next (A : Address) return Acc_Address;
pragma Inline (Next);
-- Given an address of a block, return an access to the next block
function Prev (A : Address) return Acc_Address;
pragma Inline (Prev);
-- 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
pragma Warnings (Off, Alignment);
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
pragma Warnings (Off, Storage_Size);
pragma Warnings (Off, Alignment);
Allocated : constant System.Address := Address - Pointers_Size;
begin
if Prev (Allocated).all = Null_Address then
Pool.First := Next (Allocated).all;
-- Comment needed
if Pool.First /= Null_Address then
Prev (Pool.First).all := Null_Address;
end if;
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 To_Acc_Address (A);
end Next;
----------
-- Prev --
----------
function Prev (A : Address) return Acc_Address is
begin
return To_Acc_Address (A + Pointer_Size);
end Prev;
end System.Pool_Local;
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