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

--                                                                          --

--                 GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                 --

--                                                                          --

--                  S Y S T E M . O S _ P R I M I T I V E S                 --

--                                                                          --

--                                  B o d y                                 --

--                                                                          --

--          Copyright (C) 1998-2009, Free Software Foundation, Inc.         --

--                                                                          --

-- GNARL 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/>.                                          --

--                                                                          --

-- GNARL was developed by the GNARL team at Florida State University.       --

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

--                                                                          --

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

--  This version uses gettimeofday and select

--  This file is suitable for OpenNT, Dec Unix and SCO UnixWare.

package body System.OS_Primitives is

   --  ??? These definitions are duplicated from System.OS_Interface

   --  because we don't want to depend on any package. Consider removing

   --  these declarations in System.OS_Interface and move these ones in

   --  the spec.

   type struct_timeval is record

      tv_sec  : Integer;

      tv_usec : Integer;

   end record;

   pragma Convention (C, struct_timeval);

   procedure gettimeofday

     (tv : not null access struct_timeval;

      tz : Address := Null_Address);

   pragma Import (C, gettimeofday, "gettimeofday");

   procedure C_select

     (n         : Integer := 0;

      readfds,

      writefds,

      exceptfds : Address := Null_Address;

      timeout   : not null access struct_timeval);

   pragma Import (C, C_select, "select");

   -----------

   -- Clock --

   -----------

   function Clock return Duration is

      TV : aliased struct_timeval;

   begin

      gettimeofday (TV'Access);

      return Duration (TV.tv_sec) + Duration (TV.tv_usec) / 10#1#E6;

   end Clock;

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

   -- Monotonic_Clock --

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

   function Monotonic_Clock return Duration renames Clock;

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

   -- Timed_Delay --

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

   procedure Timed_Delay

     (Time : Duration;

      Mode : Integer)

   is

      Rel_Time   : Duration;

      Abs_Time   : Duration;

      Base_Time  : constant Duration := Clock;

      Check_Time : Duration := Base_Time;

      timeval    : aliased struct_timeval;

   begin

      if Mode = Relative then

         Rel_Time := Time;

         Abs_Time := Time + Check_Time;

      else

         Rel_Time := Time - Check_Time;

         Abs_Time := Time;

      end if;

      if Rel_Time > 0.0 then

         loop

            timeval.tv_sec := Integer (Rel_Time);

            if Duration (timeval.tv_sec) > Rel_Time then

               timeval.tv_sec := timeval.tv_sec - 1;

            end if;

            timeval.tv_usec :=

              Integer ((Rel_Time - Duration (timeval.tv_sec)) * 10#1#E6);

            C_select (timeout => timeval'Unchecked_Access);

            Check_Time := Clock;

            exit when Abs_Time <= Check_Time or else Check_Time < Base_Time;

            Rel_Time := Abs_Time - Check_Time;

         end loop;

      end if;

   end Timed_Delay;

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

   -- Initialize --

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

   procedure Initialize is

   begin

      null;

   end Initialize;

end System.OS_Primitives;