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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 is for POSIX-like operating systems

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 time_t is new Long_Integer;

   type timespec is record

      tv_sec  : time_t;

      tv_nsec : Long_Integer;

   end record;

   pragma Convention (C, timespec);

   function nanosleep (rqtp, rmtp : not null access timespec) return Integer;

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

   -----------

   -- Clock --

   -----------

   function Clock return Duration is

      type timeval is array (1 .. 2) of Long_Integer;

      procedure timeval_to_duration

        (T    : not null access timeval;

         sec  : not null access Long_Integer;

         usec : not null access Long_Integer);

      pragma Import (C, timeval_to_duration, "__gnat_timeval_to_duration");

      Micro  : constant := 10**6;

      sec    : aliased Long_Integer;

      usec   : aliased Long_Integer;

      TV     : aliased timeval;

      Result : Integer;

      pragma Unreferenced (Result);

      function gettimeofday

        (Tv : access timeval;

         Tz : System.Address := System.Null_Address) return Integer;

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

   begin

      --  The return codes for gettimeofday are as follows (from man pages):

      --    EPERM  settimeofday is called by someone other than the superuser

      --    EINVAL Timezone (or something else) is invalid

      --    EFAULT One of tv or tz pointed outside accessible address space

      --  None of these codes signal a potential clock skew, hence the return

      --  value is never checked.

      Result := gettimeofday (TV'Access, System.Null_Address);

      timeval_to_duration (TV'Access, sec'Access, usec'Access);

      return Duration (sec) + Duration (usec) / Micro;

   end Clock;

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

   -- Monotonic_Clock --

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

   function Monotonic_Clock return Duration renames Clock;

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

   -- To_Timespec --

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

   function To_Timespec (D : Duration) return timespec;

   function To_Timespec (D : Duration) return timespec is

      S : time_t;

      F : Duration;

   begin

      S := time_t (Long_Long_Integer (D));

      F := D - Duration (S);

      --  If F has negative value due to a round-up, adjust for positive F

      --  value.

      if F < 0.0 then

         S := S - 1;

         F := F + 1.0;

      end if;

      return

        timespec'(tv_sec  => S,

                  tv_nsec => Long_Integer (Long_Long_Integer (F * 10#1#E9)));

   end To_Timespec;

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

   -- Timed_Delay --

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

   procedure Timed_Delay

     (Time : Duration;

      Mode : Integer)

   is

      Request    : aliased timespec;

      Remaind    : aliased timespec;

      Rel_Time   : Duration;

      Abs_Time   : Duration;

      Base_Time  : constant Duration := Clock;

      Check_Time : Duration := Base_Time;

      Result : Integer;

      pragma Unreferenced (Result);

   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

            Request := To_Timespec (Rel_Time);

            Result := nanosleep (Request'Access, Remaind'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;