166 lines
5.8 KiB
Ada
166 lines
5.8 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 . P O O L _ L O C A L --
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-- --
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-- B o d y --
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-- --
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-- Copyright (C) 1992-2011, 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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with System.Memory;
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with Ada.Unchecked_Conversion;
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package body System.Pool_Local is
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package SSE renames System.Storage_Elements;
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use type SSE.Storage_Offset;
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Pointer_Size : constant SSE.Storage_Offset := Address'Size / Storage_Unit;
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Pointers_Size : constant SSE.Storage_Offset := 2 * Pointer_Size;
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type Acc_Address is access all Address;
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function To_Acc_Address is
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new Ada.Unchecked_Conversion (Address, Acc_Address);
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-----------------------
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-- Local Subprograms --
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-----------------------
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function Next (A : Address) return Acc_Address;
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pragma Inline (Next);
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-- Given an address of a block, return an access to the next block
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function Prev (A : Address) return Acc_Address;
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pragma Inline (Prev);
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-- Given an address of a block, return an access to the previous block
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--------------
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-- Allocate --
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--------------
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procedure Allocate
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(Pool : in out Unbounded_Reclaim_Pool;
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Address : out System.Address;
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Storage_Size : SSE.Storage_Count;
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Alignment : SSE.Storage_Count)
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is
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pragma Warnings (Off, Alignment);
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Allocated : constant System.Address :=
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Memory.Alloc
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(Memory.size_t (Storage_Size + Pointers_Size));
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begin
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-- The call to Alloc returns an address whose alignment is compatible
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-- with the worst case alignment requirement for the machine; thus the
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-- Alignment argument can be safely ignored.
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if Allocated = Null_Address then
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raise Storage_Error;
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else
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Address := Allocated + Pointers_Size;
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Next (Allocated).all := Pool.First;
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Prev (Allocated).all := Null_Address;
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if Pool.First /= Null_Address then
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Prev (Pool.First).all := Allocated;
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end if;
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Pool.First := Allocated;
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end if;
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end Allocate;
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----------------
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-- Deallocate --
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----------------
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procedure Deallocate
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(Pool : in out Unbounded_Reclaim_Pool;
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Address : System.Address;
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Storage_Size : SSE.Storage_Count;
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Alignment : SSE.Storage_Count)
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is
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pragma Warnings (Off, Storage_Size);
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pragma Warnings (Off, Alignment);
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Allocated : constant System.Address := Address - Pointers_Size;
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begin
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if Prev (Allocated).all = Null_Address then
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Pool.First := Next (Allocated).all;
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-- Comment needed
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if Pool.First /= Null_Address then
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Prev (Pool.First).all := Null_Address;
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end if;
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else
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Next (Prev (Allocated).all).all := Next (Allocated).all;
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end if;
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if Next (Allocated).all /= Null_Address then
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Prev (Next (Allocated).all).all := Prev (Allocated).all;
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end if;
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Memory.Free (Allocated);
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end Deallocate;
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--------------
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-- Finalize --
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--------------
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procedure Finalize (Pool : in out Unbounded_Reclaim_Pool) is
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N : System.Address := Pool.First;
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Allocated : System.Address;
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begin
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while N /= Null_Address loop
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Allocated := N;
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N := Next (N).all;
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Memory.Free (Allocated);
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end loop;
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end Finalize;
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----------
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-- Next --
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----------
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function Next (A : Address) return Acc_Address is
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begin
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return To_Acc_Address (A);
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end Next;
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----------
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-- Prev --
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----------
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function Prev (A : Address) return Acc_Address is
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begin
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return To_Acc_Address (A + Pointer_Size);
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end Prev;
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end System.Pool_Local;
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