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) 2001-2013, 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-- 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.               --
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 default implementation of this package
33
34--  This implementation assumes that the underlying malloc/free/realloc
35--  implementation is thread safe, and thus, no additional lock is required.
36--  Note that we still need to defer abort because on most systems, an
37--  asynchronous signal (as used for implementing asynchronous abort of
38--  task) cannot safely be handled while malloc is executing.
39
40--  If you are not using Ada constructs containing the "abort" keyword, then
41--  you can remove the calls to Abort_Defer.all and Abort_Undefer.all from
42--  this unit.
43
44pragma Compiler_Unit_Warning;
45
46with Ada.Exceptions;
47with System.Soft_Links;
48with System.Parameters;
49with System.CRTL;
50
51package body System.Memory is
52
53   use Ada.Exceptions;
54   use System.Soft_Links;
55
56   function c_malloc (Size : System.CRTL.size_t) return System.Address
57    renames System.CRTL.malloc;
58
59   procedure c_free (Ptr : System.Address)
60     renames System.CRTL.free;
61
62   function c_realloc
63     (Ptr : System.Address; Size : System.CRTL.size_t) return System.Address
64     renames System.CRTL.realloc;
65
66   -----------
67   -- Alloc --
68   -----------
69
70   function Alloc (Size : size_t) return System.Address is
71      Result      : System.Address;
72      Actual_Size : size_t := Size;
73
74   begin
75      if Size = size_t'Last then
76         Raise_Exception (Storage_Error'Identity, "object too large");
77      end if;
78
79      --  Change size from zero to non-zero. We still want a proper pointer
80      --  for the zero case because pointers to zero length objects have to
81      --  be distinct, but we can't just go ahead and allocate zero bytes,
82      --  since some malloc's return zero for a zero argument.
83
84      if Size = 0 then
85         Actual_Size := 1;
86      end if;
87
88      if Parameters.No_Abort then
89         Result := c_malloc (System.CRTL.size_t (Actual_Size));
90      else
91         Abort_Defer.all;
92         Result := c_malloc (System.CRTL.size_t (Actual_Size));
93         Abort_Undefer.all;
94      end if;
95
96      if Result = System.Null_Address then
97         Raise_Exception (Storage_Error'Identity, "heap exhausted");
98      end if;
99
100      return Result;
101   end Alloc;
102
103   ----------
104   -- Free --
105   ----------
106
107   procedure Free (Ptr : System.Address) is
108   begin
109      if Parameters.No_Abort then
110         c_free (Ptr);
111      else
112         Abort_Defer.all;
113         c_free (Ptr);
114         Abort_Undefer.all;
115      end if;
116   end Free;
117
118   -------------
119   -- Realloc --
120   -------------
121
122   function Realloc
123     (Ptr  : System.Address;
124      Size : size_t)
125      return System.Address
126   is
127      Result      : System.Address;
128      Actual_Size : constant size_t := Size;
129
130   begin
131      if Size = size_t'Last then
132         Raise_Exception (Storage_Error'Identity, "object too large");
133      end if;
134
135      if Parameters.No_Abort then
136         Result := c_realloc (Ptr, System.CRTL.size_t (Actual_Size));
137      else
138         Abort_Defer.all;
139         Result := c_realloc (Ptr, System.CRTL.size_t (Actual_Size));
140         Abort_Undefer.all;
141      end if;
142
143      if Result = System.Null_Address then
144         Raise_Exception (Storage_Error'Identity, "heap exhausted");
145      end if;
146
147      return Result;
148   end Realloc;
149
150end System.Memory;
151