1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
5 -- S Y S T E M . P O O L _ L O C A L --
9 -- Copyright (C) 1992-2007, 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 2, 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. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, USA. --
22 -- As a special exception, if other files instantiate generics from this --
23 -- unit, or you link this unit with other files to produce an executable, --
24 -- this unit does not by itself cause the resulting executable to be --
25 -- covered by the GNU General Public License. This exception does not --
26 -- however invalidate any other reasons why the executable file might be --
27 -- covered by the GNU Public License. --
29 -- GNAT was originally developed by the GNAT team at New York University. --
30 -- Extensive contributions were provided by Ada Core Technologies Inc. --
32 ------------------------------------------------------------------------------
36 with Ada.Unchecked_Conversion;
38 package body System.Pool_Local is
40 package SSE renames System.Storage_Elements;
41 use type SSE.Storage_Offset;
43 Pointer_Size : constant SSE.Storage_Offset := Address'Size / Storage_Unit;
44 Pointers_Size : constant SSE.Storage_Offset := 2 * Pointer_Size;
46 type Acc_Address is access all Address;
47 function To_Acc_Address is
48 new Ada.Unchecked_Conversion (Address, Acc_Address);
50 -----------------------
51 -- Local Subprograms --
52 -----------------------
54 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;
60 -- Given an address of a block, return an access to the previous block
67 (Pool : in out Unbounded_Reclaim_Pool;
68 Address : out System.Address;
69 Storage_Size : SSE.Storage_Count;
70 Alignment : SSE.Storage_Count)
72 pragma Warnings (Off, Alignment);
74 Allocated : constant System.Address :=
76 (Memory.size_t (Storage_Size + Pointers_Size));
79 -- The call to Alloc returns an address whose alignment is compatible
80 -- with the worst case alignment requirement for the machine; thus the
81 -- Alignment argument can be safely ignored.
83 if Allocated = Null_Address then
86 Address := Allocated + Pointers_Size;
87 Next (Allocated).all := Pool.First;
88 Prev (Allocated).all := Null_Address;
90 if Pool.First /= Null_Address then
91 Prev (Pool.First).all := Allocated;
94 Pool.First := Allocated;
103 (Pool : in out Unbounded_Reclaim_Pool;
104 Address : System.Address;
105 Storage_Size : SSE.Storage_Count;
106 Alignment : SSE.Storage_Count)
108 pragma Warnings (Off, Storage_Size);
109 pragma Warnings (Off, Alignment);
111 Allocated : constant System.Address := Address - Pointers_Size;
114 if Prev (Allocated).all = Null_Address then
115 Pool.First := Next (Allocated).all;
116 Prev (Pool.First).all := Null_Address;
118 Next (Prev (Allocated).all).all := Next (Allocated).all;
121 if Next (Allocated).all /= Null_Address then
122 Prev (Next (Allocated).all).all := Prev (Allocated).all;
125 Memory.Free (Allocated);
132 procedure Finalize (Pool : in out Unbounded_Reclaim_Pool) is
133 N : System.Address := Pool.First;
134 Allocated : System.Address;
137 while N /= Null_Address loop
140 Memory.Free (Allocated);
148 function Next (A : Address) return Acc_Address is
150 return To_Acc_Address (A);
157 function Prev (A : Address) return Acc_Address is
159 return To_Acc_Address (A + Pointer_Size);
162 end System.Pool_Local;