1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT RUN-TIME COMPONENTS                         --
4--                                                                          --
5--                   S Y S T E M . R A N D O M _ S E E D                    --
6--                                                                          --
7--                                 B o d y                                  --
8--                                                                          --
9--          Copyright (C) 2011-2012, 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--  Version used on all systems except Ravenscar where Calendar is unavailable
33
34with Ada.Calendar; use Ada.Calendar;
35with Ada.Unchecked_Conversion;
36
37package body System.Random_Seed is
38
39   Y2K : constant Time :=
40           Time_Of (Year => 2000, Month => 1, Day => 1, Seconds => 0.0);
41   --  First day of Year 2000, to get a duration
42
43   function To_U64 is
44     new Ada.Unchecked_Conversion (Duration, Interfaces.Unsigned_64);
45
46   --------------
47   -- Get_Seed --
48   --------------
49
50   function Get_Seed return Interfaces.Unsigned_64 is
51   begin
52      return To_U64 (Clock - Y2K);
53   end Get_Seed;
54
55end System.Random_Seed;
56