1------------------------------------------------------------------------------ 2-- -- 3-- GNAT RUN-TIME COMPONENTS -- 4-- -- 5-- S Y S T E M . M E M O R Y -- 6-- -- 7-- S p e c -- 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 package provides the low level memory allocation/deallocation 33-- mechanisms used by GNAT. 34 35-- To provide an alternate implementation, simply recompile the modified 36-- body of this package with gnatmake -u -a -g s-memory.adb and make sure 37-- that the ali and object files for this unit are found in the object 38-- search path. 39 40-- This unit may be used directly from an application program by providing 41-- an appropriate WITH, and the interface can be expected to remain stable. 42 43pragma Compiler_Unit_Warning; 44 45package System.Memory is 46 pragma Elaborate_Body; 47 48 type size_t is mod 2 ** Standard'Address_Size; 49 -- Note: the reason we redefine this here instead of using the 50 -- definition in Interfaces.C is that we do not want to drag in 51 -- all of Interfaces.C just because System.Memory is used. 52 53 function Alloc (Size : size_t) return System.Address; 54 -- This is the low level allocation routine. Given a size in storage 55 -- units, it returns the address of a maximally aligned block of 56 -- memory. The implementation of this routine is guaranteed to be 57 -- task safe, and also aborts are deferred if necessary. 58 -- 59 -- If size_t is set to size_t'Last on entry, then a Storage_Error 60 -- exception is raised with a message "object too large". 61 -- 62 -- If size_t is set to zero on entry, then a minimal (but non-zero) 63 -- size block is allocated. 64 -- 65 -- Note: this is roughly equivalent to the standard C malloc call 66 -- with the additional semantics as described above. 67 68 procedure Free (Ptr : System.Address); 69 -- This is the low level free routine. It frees a block previously 70 -- allocated with a call to Alloc. As in the case of Alloc, this 71 -- call is guaranteed task safe, and aborts are deferred. 72 -- 73 -- Note: this is roughly equivalent to the standard C free call 74 -- with the additional semantics as described above. 75 76 function Realloc 77 (Ptr : System.Address; 78 Size : size_t) return System.Address; 79 -- This is the low level reallocation routine. It takes an existing 80 -- block address returned by a previous call to Alloc or Realloc, 81 -- and reallocates the block. The size can either be increased or 82 -- decreased. If possible the reallocation is done in place, so that 83 -- the returned result is the same as the value of Ptr on entry. 84 -- However, it may be necessary to relocate the block to another 85 -- address, in which case the information is copied to the new 86 -- block, and the old block is freed. The implementation of this 87 -- routine is guaranteed to be task safe, and also aborts are 88 -- deferred as necessary. 89 -- 90 -- If size_t is set to size_t'Last on entry, then a Storage_Error 91 -- exception is raised with a message "object too large". 92 -- 93 -- If size_t is set to zero on entry, then a minimal (but non-zero) 94 -- size block is allocated. 95 -- 96 -- Note: this is roughly equivalent to the standard C realloc call 97 -- with the additional semantics as described above. 98 99private 100 101 -- The following names are used from the generated compiler code 102 103 pragma Export (C, Alloc, "__gnat_malloc"); 104 pragma Export (C, Free, "__gnat_free"); 105 pragma Export (C, Realloc, "__gnat_realloc"); 106 107end System.Memory; 108