1------------------------------------------------------------------------------
2--                                                                          --
3--                 GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS                 --
4--                                                                          --
5--                  S Y S T E M . O S _ P R I M I T I V E S                 --
6--                                                                          --
7--                                  B o d y                                 --
8--                                                                          --
9--          Copyright (C) 1998-2009, Free Software Foundation, Inc.         --
10--                                                                          --
11-- GNARL 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-- GNARL was developed by the GNARL team at Florida State University.       --
28-- Extensive contributions were provided by Ada Core Technologies, Inc.     --
29--                                                                          --
30------------------------------------------------------------------------------
31
32--  This version is for POSIX-like operating systems
33
34package body System.OS_Primitives is
35
36   --  ??? These definitions are duplicated from System.OS_Interface
37   --  because we don't want to depend on any package. Consider removing
38   --  these declarations in System.OS_Interface and move these ones in
39   --  the spec.
40
41   type time_t is new Long_Integer;
42
43   type timespec is record
44      tv_sec  : time_t;
45      tv_nsec : Long_Integer;
46   end record;
47   pragma Convention (C, timespec);
48
49   function nanosleep (rqtp, rmtp : not null access timespec) return Integer;
50   pragma Import (C, nanosleep, "nanosleep");
51
52   -----------
53   -- Clock --
54   -----------
55
56   function Clock return Duration is
57      type timeval is array (1 .. 2) of Long_Integer;
58
59      procedure timeval_to_duration
60        (T    : not null access timeval;
61         sec  : not null access Long_Integer;
62         usec : not null access Long_Integer);
63      pragma Import (C, timeval_to_duration, "__gnat_timeval_to_duration");
64
65      Micro  : constant := 10**6;
66      sec    : aliased Long_Integer;
67      usec   : aliased Long_Integer;
68      TV     : aliased timeval;
69      Result : Integer;
70      pragma Unreferenced (Result);
71
72      function gettimeofday
73        (Tv : access timeval;
74         Tz : System.Address := System.Null_Address) return Integer;
75      pragma Import (C, gettimeofday, "gettimeofday");
76
77   begin
78      --  The return codes for gettimeofday are as follows (from man pages):
79      --    EPERM  settimeofday is called by someone other than the superuser
80      --    EINVAL Timezone (or something else) is invalid
81      --    EFAULT One of tv or tz pointed outside accessible address space
82
83      --  None of these codes signal a potential clock skew, hence the return
84      --  value is never checked.
85
86      Result := gettimeofday (TV'Access, System.Null_Address);
87      timeval_to_duration (TV'Access, sec'Access, usec'Access);
88      return Duration (sec) + Duration (usec) / Micro;
89   end Clock;
90
91   ---------------------
92   -- Monotonic_Clock --
93   ---------------------
94
95   function Monotonic_Clock return Duration renames Clock;
96
97   -----------------
98   -- To_Timespec --
99   -----------------
100
101   function To_Timespec (D : Duration) return timespec;
102
103   function To_Timespec (D : Duration) return timespec is
104      S : time_t;
105      F : Duration;
106
107   begin
108      S := time_t (Long_Long_Integer (D));
109      F := D - Duration (S);
110
111      --  If F has negative value due to a round-up, adjust for positive F
112      --  value.
113
114      if F < 0.0 then
115         S := S - 1;
116         F := F + 1.0;
117      end if;
118
119      return
120        timespec'(tv_sec  => S,
121                  tv_nsec => Long_Integer (Long_Long_Integer (F * 10#1#E9)));
122   end To_Timespec;
123
124   -----------------
125   -- Timed_Delay --
126   -----------------
127
128   procedure Timed_Delay
129     (Time : Duration;
130      Mode : Integer)
131   is
132      Request    : aliased timespec;
133      Remaind    : aliased timespec;
134      Rel_Time   : Duration;
135      Abs_Time   : Duration;
136      Base_Time  : constant Duration := Clock;
137      Check_Time : Duration := Base_Time;
138
139      Result : Integer;
140      pragma Unreferenced (Result);
141
142   begin
143      if Mode = Relative then
144         Rel_Time := Time;
145         Abs_Time := Time + Check_Time;
146      else
147         Rel_Time := Time - Check_Time;
148         Abs_Time := Time;
149      end if;
150
151      if Rel_Time > 0.0 then
152         loop
153            Request := To_Timespec (Rel_Time);
154            Result := nanosleep (Request'Access, Remaind'Access);
155            Check_Time := Clock;
156
157            exit when Abs_Time <= Check_Time or else Check_Time < Base_Time;
158
159            Rel_Time := Abs_Time - Check_Time;
160         end loop;
161      end if;
162   end Timed_Delay;
163
164   ----------------
165   -- Initialize --
166   ----------------
167
168   procedure Initialize is
169   begin
170      null;
171   end Initialize;
172
173end System.OS_Primitives;
174