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------------------------------------------------------------------------------

--                                                                          --

--                         GNAT RUN-TIME COMPONENTS                         --

--                                                                          --

--                         S Y S T E M . M E M O R Y                        --

--                                                                          --

--                                 B o d y                                  --

--                                                                          --

--          Copyright (C) 2001-2009, Free Software Foundation, Inc.         --

--                                                                          --

-- 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 3,  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.                                     --

--                                                                          --

-- As a special exception under Section 7 of GPL version 3, you are granted --

-- additional permissions described in the GCC Runtime Library Exception,   --

-- version 3.1, as published by the Free Software Foundation.               --

--                                                                          --

-- You should have received a copy of the GNU General Public License and    --

-- a copy of the GCC Runtime Library Exception along with this program;     --

-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --

-- <http://www.gnu.org/licenses/>.                                          --

--                                                                          --

-- GNAT was originally developed  by the GNAT team at  New York University. --

-- Extensive contributions were provided by Ada Core Technologies Inc.      --

--                                                                          --

------------------------------------------------------------------------------

--  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 abort because on most systems, an

--  asynchronous signal (as used for implementing asynchronous abort 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.

pragma Compiler_Unit;

with Ada.Exceptions;

with System.Soft_Links;

with System.Parameters;

with System.CRTL;

package body System.Memory is

   use Ada.Exceptions;

   use System.Soft_Links;

   function c_malloc (Size : System.CRTL.size_t) return System.Address

    renames System.CRTL.malloc;

   procedure c_free (Ptr : System.Address)

     renames System.CRTL.free;

   function c_realloc

     (Ptr : System.Address; Size : System.CRTL.size_t) return System.Address

     renames System.CRTL.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;

      if Parameters.No_Abort then

         Result := c_malloc (System.CRTL.size_t (Actual_Size));

      else

         Abort_Defer.all;

         Result := c_malloc (System.CRTL.size_t (Actual_Size));

         Abort_Undefer.all;

      end if;

      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

      if Parameters.No_Abort then

         c_free (Ptr);

      else

         Abort_Defer.all;

         c_free (Ptr);

         Abort_Undefer.all;

      end if;

   end Free;

   -------------

   -- Realloc --

   -------------

   function Realloc

     (Ptr  : System.Address;

      Size : size_t)

      return System.Address

   is

      Result      : System.Address;

      Actual_Size : constant size_t := Size;

   begin

      if Size = size_t'Last then

         Raise_Exception (Storage_Error'Identity, "object too large");

      end if;

      if Parameters.No_Abort then

         Result := c_realloc (Ptr, System.CRTL.size_t (Actual_Size));

      else

         Abort_Defer.all;

         Result := c_realloc (Ptr, System.CRTL.size_t (Actual_Size));

         Abort_Undefer.all;

      end if;

      if Result = System.Null_Address then

         Raise_Exception (Storage_Error'Identity, "heap exhausted");

      end if;

      return Result;

   end Realloc;

end System.Memory;