1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
5 -- S Y S T E M . P O O L _ L O C A L --
9 -- Copyright (C) 1992-2009, Free Software Foundation, Inc. --
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 3, 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. --
18 -- As a special exception under Section 7 of GPL version 3, you are granted --
19 -- additional permissions described in the GCC Runtime Library Exception, --
20 -- version 3.1, as published by the Free Software Foundation. --
22 -- You should have received a copy of the GNU General Public License and --
23 -- a copy of the GCC Runtime Library Exception along with this program; --
24 -- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
25 -- <http://www.gnu.org/licenses/>. --
27 -- GNAT was originally developed by the GNAT team at New York University. --
28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
30 ------------------------------------------------------------------------------
34 with Ada.Unchecked_Conversion;
36 package body System.Pool_Local is
38 package SSE renames System.Storage_Elements;
39 use type SSE.Storage_Offset;
41 Pointer_Size : constant SSE.Storage_Offset := Address'Size / Storage_Unit;
42 Pointers_Size : constant SSE.Storage_Offset := 2 * Pointer_Size;
44 type Acc_Address is access all Address;
45 function To_Acc_Address is
46 new Ada.Unchecked_Conversion (Address, Acc_Address);
48 -----------------------
49 -- Local Subprograms --
50 -----------------------
52 function Next (A : Address) return Acc_Address;
54 -- Given an address of a block, return an access to the next block
56 function Prev (A : Address) return Acc_Address;
58 -- Given an address of a block, return an access to the previous block
65 (Pool : in out Unbounded_Reclaim_Pool;
66 Address : out System.Address;
67 Storage_Size : SSE.Storage_Count;
68 Alignment : SSE.Storage_Count)
70 pragma Warnings (Off, Alignment);
72 Allocated : constant System.Address :=
74 (Memory.size_t (Storage_Size + Pointers_Size));
77 -- The call to Alloc returns an address whose alignment is compatible
78 -- with the worst case alignment requirement for the machine; thus the
79 -- Alignment argument can be safely ignored.
81 if Allocated = Null_Address then
84 Address := Allocated + Pointers_Size;
85 Next (Allocated).all := Pool.First;
86 Prev (Allocated).all := Null_Address;
88 if Pool.First /= Null_Address then
89 Prev (Pool.First).all := Allocated;
92 Pool.First := Allocated;
101 (Pool : in out Unbounded_Reclaim_Pool;
102 Address : System.Address;
103 Storage_Size : SSE.Storage_Count;
104 Alignment : SSE.Storage_Count)
106 pragma Warnings (Off, Storage_Size);
107 pragma Warnings (Off, Alignment);
109 Allocated : constant System.Address := Address - Pointers_Size;
112 if Prev (Allocated).all = Null_Address then
113 Pool.First := Next (Allocated).all;
114 Prev (Pool.First).all := Null_Address;
116 Next (Prev (Allocated).all).all := Next (Allocated).all;
119 if Next (Allocated).all /= Null_Address then
120 Prev (Next (Allocated).all).all := Prev (Allocated).all;
123 Memory.Free (Allocated);
130 procedure Finalize (Pool : in out Unbounded_Reclaim_Pool) is
131 N : System.Address := Pool.First;
132 Allocated : System.Address;
135 while N /= Null_Address loop
138 Memory.Free (Allocated);
146 function Next (A : Address) return Acc_Address is
148 return To_Acc_Address (A);
155 function Prev (A : Address) return Acc_Address is
157 return To_Acc_Address (A + Pointer_Size);
160 end System.Pool_Local;