1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
5 -- S Y S T E M . P O O L _ L O C A L --
11 -- Copyright (C) 1992-2001, Free Software Foundation, Inc. --
13 -- GNAT is free software; you can redistribute it and/or modify it under --
14 -- terms of the GNU General Public License as published by the Free Soft- --
15 -- ware Foundation; either version 2, or (at your option) any later ver- --
16 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
17 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
18 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
19 -- for more details. You should have received a copy of the GNU General --
20 -- Public License distributed with GNAT; see file COPYING. If not, write --
21 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
22 -- MA 02111-1307, USA. --
24 -- As a special exception, if other files instantiate generics from this --
25 -- unit, or you link this unit with other files to produce an executable, --
26 -- this unit does not by itself cause the resulting executable to be --
27 -- covered by the GNU General Public License. This exception does not --
28 -- however invalidate any other reasons why the executable file might be --
29 -- covered by the GNU Public License. --
31 -- GNAT was originally developed by the GNAT team at New York University. --
32 -- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
34 ------------------------------------------------------------------------------
37 with System.Storage_Elements;
38 with System.Address_To_Access_Conversions;
40 package body System.Pool_Local is
42 package SSE renames System.Storage_Elements;
43 use type SSE.Storage_Offset;
45 Pointer_Size : constant SSE.Storage_Offset := Address'Size / Storage_Unit;
46 Pointers_Size : constant SSE.Storage_Offset := 2 * Pointer_Size;
48 type Acc_Address is access all Address;
49 package Addr is new Address_To_Access_Conversions (Address);
51 -----------------------
52 -- Local Subprograms --
53 -----------------------
55 function Next (A : Address) return Acc_Address;
56 -- Given an address of a block, return an access to the next block
58 function Prev (A : Address) return Acc_Address;
59 -- Given an address of a block, return an access to the previous block
66 (Pool : in out Unbounded_Reclaim_Pool;
67 Address : out System.Address;
68 Storage_Size : SSE.Storage_Count;
69 Alignment : SSE.Storage_Count)
71 Allocated : constant System.Address :=
72 Memory.Alloc (Memory.size_t (Storage_Size + Pointers_Size));
75 -- The call to Alloc returns an address whose alignment is compatible
76 -- with the worst case alignment requirement for the machine; thus the
77 -- Alignment argument can be safely ignored.
79 if Allocated = Null_Address then
82 Address := Allocated + Pointers_Size;
83 Next (Allocated).all := Pool.First;
84 Prev (Allocated).all := Null_Address;
86 if Pool.First /= Null_Address then
87 Prev (Pool.First).all := Allocated;
90 Pool.First := Allocated;
99 (Pool : in out Unbounded_Reclaim_Pool;
100 Address : System.Address;
101 Storage_Size : SSE.Storage_Count;
102 Alignment : SSE.Storage_Count)
104 Allocated : constant System.Address := Address - Pointers_Size;
106 if Prev (Allocated).all = Null_Address then
107 Pool.First := Next (Allocated).all;
108 Prev (Pool.First).all := Null_Address;
110 Next (Prev (Allocated).all).all := Next (Allocated).all;
113 if Next (Allocated).all /= Null_Address then
114 Prev (Next (Allocated).all).all := Prev (Allocated).all;
117 Memory.Free (Allocated);
124 procedure Finalize (Pool : in out Unbounded_Reclaim_Pool) is
125 N : System.Address := Pool.First;
126 Allocated : System.Address;
129 while N /= Null_Address loop
132 Memory.Free (Allocated);
140 function Next (A : Address) return Acc_Address is
142 return Acc_Address (Addr.To_Pointer (A));
149 function Prev (A : Address) return Acc_Address is
151 return Acc_Address (Addr.To_Pointer (A + Pointer_Size));
154 end System.Pool_Local;