File : s-memory-xi.adb
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT RUN-TIME COMPONENTS --
4 -- --
5 -- S Y S T E M . M E M O R Y --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 2001-2010, Free Software Foundation, Inc. --
10 -- --
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. --
17 -- --
18 -- --
19 -- --
20 -- --
21 -- --
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/>. --
26 -- --
27 -- GNAT was originally developed by the GNAT team at New York University. --
28 -- Extensive contributions were provided by Ada Core Technologies Inc. --
29 -- --
30 ------------------------------------------------------------------------------
31
32 -- This is the simplified implementation of this package, for use with a
33 -- configurable run-time library.
34
35 -- This implementation assumes that the underlying malloc/free/realloc
36 -- implementation is *not* thread safe, and thus, explicit lock is required.
37
38 with Ada.Exceptions;
39
40 with System.Soft_Links;
41
42 package body System.Memory is
43
44 use Ada.Exceptions;
45 use System.Soft_Links;
46
47 function c_malloc (Size : size_t) return System.Address;
48 pragma Import (C, c_malloc, "malloc");
49
50 procedure c_free (Ptr : System.Address);
51 pragma Import (C, c_free, "free");
52
53 function c_realloc
54 (Ptr : System.Address; Size : size_t) return System.Address;
55 pragma Import (C, c_realloc, "realloc");
56
57 -----------
58 -- Alloc --
59 -----------
60
61 function Alloc (Size : size_t) return System.Address is
62 Result : System.Address;
63 Actual_Size : size_t := Size;
64
65 begin
66 if Size = size_t'Last then
67 Raise_Exception (Storage_Error'Identity, "object too large");
68 end if;
69
70 -- Change size from zero to non-zero. We still want a proper pointer
71 -- for the zero case because pointers to zero length objects have to
72 -- be distinct, but we can't just go ahead and allocate zero bytes,
73 -- since some malloc's return zero for a zero argument.
74
75 if Size = 0 then
76 Actual_Size := 1;
77 end if;
78
79 Lock_Task.all;
80
81 Result := c_malloc (Actual_Size);
82
83 Unlock_Task.all;
84
85 if Result = System.Null_Address then
86 Raise_Exception (Storage_Error'Identity, "heap exhausted");
87 end if;
88
89 return Result;
90 end Alloc;
91
92 ----------
93 -- Free --
94 ----------
95
96 procedure Free (Ptr : System.Address) is
97 begin
98 Lock_Task.all;
99
100 c_free (Ptr);
101
102 Unlock_Task.all;
103 end Free;
104
105 -------------
106 -- Realloc --
107 -------------
108
109 function Realloc
110 (Ptr : System.Address;
111 Size : size_t)
112 return System.Address
113 is
114 Result : System.Address;
115
116 begin
117 if Size = size_t'Last then
118 Raise_Exception (Storage_Error'Identity, "object too large");
119 end if;
120
121 Lock_Task.all;
122
123 Result := c_realloc (Ptr, Size);
124
125 Unlock_Task.all;
126
127 if Result = System.Null_Address then
128 Raise_Exception (Storage_Error'Identity, "heap exhausted");
129 end if;
130
131 return Result;
132 end Realloc;
133
134 end System.Memory;