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------------------------------------------------------------------------------
-- --
-- GNAT RUN-TIME COMPONENTS --
-- --
-- S Y S T E M . M E M O R Y --
-- --
-- S p e c --
-- --
-- $Revision: 1.2 $
-- --
-- Copyright (C) 2001 Free Software Foundation, Inc. --
-- --
-- This specification is derived from the Ada Reference Manual for use with --
-- GNAT. The copyright notice above, and the license provisions that follow --
-- apply solely to the contents of the part following the private keyword. --
-- --
-- GNAT is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- ware Foundation; either version 2, or (at your option) any later ver- --
-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNAT; see file COPYING. If not, write --
-- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
-- MA 02111-1307, USA. --
-- --
-- As a special exception, if other files instantiate generics from this --
-- unit, or you link this unit with other files to produce an executable, --
-- this unit does not by itself cause the resulting executable to be --
-- covered by the GNU General Public License. This exception does not --
-- however invalidate any other reasons why the executable file might be --
-- covered by the GNU Public License. --
-- --
-- GNAT was originally developed by the GNAT team at New York University. --
-- It is now maintained by Ada Core Technologies Inc (http://www.gnat.com). --
-- --
------------------------------------------------------------------------------
-- This is the default implementation of this package.
-- This implementation assumes that the underlying malloc/free/realloc
-- implementation is thread safe, and thus, no additional lock is required.
-- Note that we still need to defer abortion because on most systems,
-- an asynchronous signal (as used for implementing asynchronous abortion
-- of task) cannot safely be handled while malloc is executing.
-- If you are not using Ada constructs containing the "abort" keyword,
-- then you can remove the calls to Abort_Defer.all and Abort_Undefer.all
-- from this unit.
with Ada.Exceptions;
with System.Soft_Links;
package body System.Memory is
use Ada.Exceptions;
use System.Soft_Links;
function c_malloc (Size : size_t) return System.Address;
pragma Import (C, c_malloc, "malloc");
procedure c_free (Ptr : System.Address);
pragma Import (C, c_free, "free");
function c_realloc
(Ptr : System.Address; Size : size_t) return System.Address;
pragma Import (C, c_realloc, "realloc");
-----------
-- Alloc --
-----------
function Alloc (Size : size_t) return System.Address is
Result : System.Address;
Actual_Size : size_t := Size;
begin
if Size = size_t'Last then
Raise_Exception (Storage_Error'Identity, "object too large");
end if;
-- Change size from zero to non-zero. We still want a proper pointer
-- for the zero case because pointers to zero length objects have to
-- be distinct, but we can't just go ahead and allocate zero bytes,
-- since some malloc's return zero for a zero argument.
if Size = 0 then
Actual_Size := 1;
end if;
Abort_Defer.all;
Result := c_malloc (Actual_Size);
Abort_Undefer.all;
if Result = System.Null_Address then
Raise_Exception (Storage_Error'Identity, "heap exhausted");
end if;
return Result;
end Alloc;
----------
-- Free --
----------
procedure Free (Ptr : System.Address) is
begin
Abort_Defer.all;
c_free (Ptr);
Abort_Undefer.all;
end Free;
-------------
-- Realloc --
-------------
function Realloc
(Ptr : System.Address;
Size : size_t)
return System.Address
is
Result : System.Address;
Actual_Size : size_t := Size;
begin
if Size = size_t'Last then
Raise_Exception (Storage_Error'Identity, "object too large");
end if;
Abort_Defer.all;
Result := c_realloc (Ptr, Actual_Size);
Abort_Undefer.all;
if Result = System.Null_Address then
Raise_Exception (Storage_Error'Identity, "heap exhausted");
end if;
return Result;
end Realloc;
end System.Memory;
|
