| ------------------------------------------------------------------------------ |
| -- -- |
| -- GNAT RUN-TIME COMPONENTS -- |
| -- -- |
| -- S Y S T E M . M E M O R Y -- |
| -- -- |
| -- S p e c -- |
| -- -- |
| -- Copyright (C) 2001-2003 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 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, 51 Franklin Street, Fifth Floor, -- |
| -- Boston, MA 02110-1301, 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. -- |
| -- Extensive contributions were provided by Ada Core Technologies Inc. -- |
| -- -- |
| ------------------------------------------------------------------------------ |
| |
| -- This package provides the low level memory allocation/deallocation |
| -- mechanisms used by GNAT. |
| |
| -- To provide an alternate implementation, simply recompile the modified |
| -- body of this package with gnatmake -u -a -g s-memory.adb and make sure |
| -- that the ali and object files for this unit are found in the object |
| -- search path. |
| |
| -- This unit may be used directly from an application program by providing |
| -- an appropriate WITH, and the interface can be expected to remain stable. |
| |
| package System.Memory is |
| pragma Elaborate_Body; |
| |
| type size_t is mod 2 ** Standard'Address_Size; |
| -- Note: the reason we redefine this here instead of using the |
| -- definition in Interfaces.C is that we do not want to drag in |
| -- all of Interfaces.C just because System.Memory is used. |
| |
| function Alloc (Size : size_t) return System.Address; |
| -- This is the low level allocation routine. Given a size in storage |
| -- units, it returns the address of a maximally aligned block of |
| -- memory. The implementation of this routine is guaranteed to be |
| -- task safe, and also aborts are deferred if necessary. |
| -- |
| -- If size_t is set to size_t'Last on entry, then a Storage_Error |
| -- exception is raised with a message "object too large". |
| -- |
| -- If size_t is set to zero on entry, then a minimal (but non-zero) |
| -- size block is allocated. |
| -- |
| -- Note: this is roughly equivalent to the standard C malloc call |
| -- with the additional semantics as described above. |
| |
| procedure Free (Ptr : System.Address); |
| -- This is the low level free routine. It frees a block previously |
| -- allocated with a call to Alloc. As in the case of Alloc, this |
| -- call is guaranteed task safe, and aborts are deferred. |
| -- |
| -- Note: this is roughly equivalent to the standard C free call |
| -- with the additional semantics as described above. |
| |
| function Realloc |
| (Ptr : System.Address; |
| Size : size_t) |
| return System.Address; |
| -- This is the low level reallocation routine. It takes an existing |
| -- block address returned by a previous call to Alloc or Realloc, |
| -- and reallocates the block. The size can either be increased or |
| -- decreased. If possible the reallocation is done in place, so that |
| -- the returned result is the same as the value of Ptr on entry. |
| -- However, it may be necessary to relocate the block to another |
| -- address, in which case the information is copied to the new |
| -- block, and the old block is freed. The implementation of this |
| -- routine is guaranteed to be task safe, and also aborts are |
| -- deferred as necessary. |
| -- |
| -- If size_t is set to size_t'Last on entry, then a Storage_Error |
| -- exception is raised with a message "object too large". |
| -- |
| -- If size_t is set to zero on entry, then a minimal (but non-zero) |
| -- size block is allocated. |
| -- |
| -- Note: this is roughly equivalent to the standard C realloc call |
| -- with the additional semantics as described above. |
| |
| private |
| |
| -- The following names are used from the generated compiler code |
| |
| pragma Export (C, Alloc, "__gnat_malloc"); |
| pragma Export (C, Free, "__gnat_free"); |
| pragma Export (C, Realloc, "__gnat_realloc"); |
| |
| end System.Memory; |
