gcc/ada/s-memcop.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT RUN-TIME COMPONENTS                         --
   4 --                                                                          --
   5 --                   S Y S T E M . M E M O R Y _ C O P Y                    --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 2001-2014, Free Software Foundation, Inc.         --
  10 --                                                                          --
  11 -- This specification is derived from the Ada Reference Manual for use with --
  12 -- GNAT. The copyright notice above, and the license provisions that follow --
  13 -- apply solely to the  contents of the part following the private keyword. --
  14 --                                                                          --
  15 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  16 -- terms of the  GNU General Public License as published  by the Free Soft- --
  17 -- ware  Foundation;  either version 3,  or (at your option) any later ver- --
  18 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  19 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  20 -- or FITNESS FOR A PARTICULAR PURPOSE.                                     --
  21 --                                                                          --
  22 -- As a special exception under Section 7 of GPL version 3, you are granted --
  23 -- additional permissions described in the GCC Runtime Library Exception,   --
  24 -- version 3.1, as published by the Free Software Foundation.               --
  25 --                                                                          --
  26 -- You should have received a copy of the GNU General Public License and    --
  27 -- a copy of the GCC Runtime Library Exception along with this program;     --
  28 -- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
  29 -- <http://www.gnu.org/licenses/>.                                          --
  30 --                                                                          --
  31 -- GNAT was originally developed  by the GNAT team at  New York University. --
  32 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  33 --                                                                          --
  34 ------------------------------------------------------------------------------
  35
  36 --  This package provides general block copy mechanisms analogous to those
  37 --  provided by the C routines memcpy and memmove allowing for copies with
  38 --  and without possible overlap of the operands.
  39
  40 --  The idea is to allow a configurable run-time to provide this capability
  41 --  for use by the compiler without dragging in C-run time routines.
  42
  43 with System.CRTL;
  44 --  The above with is contrary to the intent ???
  45
  46 package System.Memory_Copy is
  47    pragma Preelaborate;
  48
  49    procedure memcpy (S1 : Address; S2 : Address; N : System.CRTL.size_t)
  50      renames System.CRTL.memcpy;
  51    --  Copies N storage units from area starting at S2 to area starting
  52    --  at S1 without any check for buffer overflow. The memory areas
  53    --  must not overlap, or the result of this call is undefined.
  54
  55    procedure memmove (S1 : Address; S2 : Address; N : System.CRTL.size_t)
  56       renames System.CRTL.memmove;
  57    --  Copies N storage units from area starting at S2 to area starting
  58    --  at S1 without any check for buffer overflow. The difference between
  59    --  this memmove and memcpy is that with memmove, the storage areas may
  60    --  overlap (forwards or backwards) and the result is correct (i.e. it
  61    --  is as if S2 is first moved to a temporary area, and then this area
  62    --  is copied to S1 in a separate step).
  63
  64    --  In the standard library, these are just interfaced to the C routines.
  65    --  But in the HI-E (high integrity version) they may be reprogrammed to
  66    --  meet certification requirements (and marked High_Integrity).
  67
  68    --  Note that in high integrity mode these routines are by default not
  69    --  available, and the HI-E compiler will as a result generate implicit
  70    --  loops (which will violate the restriction No_Implicit_Loops).
  71
  72 end System.Memory_Copy;