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) 1998-2021, 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 uses gettimeofday and select
33--  This file is suitable for OpenNT, Dec Unix and SCO UnixWare.
34
35package body System.OS_Primitives is
36
37   --  ??? These definitions are duplicated from System.OS_Interface
38   --  because we don't want to depend on any package. Consider removing
39   --  these declarations in System.OS_Interface and move these ones in
40   --  the spec.
41
42   type struct_timeval is record
43      tv_sec  : Integer;
44      tv_usec : Integer;
45   end record;
46   pragma Convention (C, struct_timeval);
47
48   procedure gettimeofday
49     (tv : not null access struct_timeval;
50      tz : Address := Null_Address);
51   pragma Import (C, gettimeofday, "gettimeofday");
52
53   procedure C_select
54     (n         : Integer := 0;
55      readfds,
56      writefds,
57      exceptfds : Address := Null_Address;
58      timeout   : not null access struct_timeval);
59   pragma Import (C, C_select, "select");
60
61   -----------
62   -- Clock --
63   -----------
64
65   function Clock return Duration is
66      TV : aliased struct_timeval;
67
68   begin
69      gettimeofday (TV'Access);
70      return Duration (TV.tv_sec) + Duration (TV.tv_usec) / 10#1#E6;
71   end Clock;
72
73   -----------------
74   -- Timed_Delay --
75   -----------------
76
77   procedure Timed_Delay
78     (Time : Duration;
79      Mode : Integer)
80   is
81      Rel_Time   : Duration;
82      Abs_Time   : Duration;
83      Base_Time  : constant Duration := Clock;
84      Check_Time : Duration := Base_Time;
85      timeval    : aliased struct_timeval;
86
87   begin
88      if Mode = Relative then
89         Rel_Time := Time;
90         Abs_Time := Time + Check_Time;
91      else
92         Rel_Time := Time - Check_Time;
93         Abs_Time := Time;
94      end if;
95
96      if Rel_Time > 0.0 then
97         loop
98            timeval.tv_sec := Integer (Rel_Time);
99
100            if Duration (timeval.tv_sec) > Rel_Time then
101               timeval.tv_sec := timeval.tv_sec - 1;
102            end if;
103
104            timeval.tv_usec :=
105              Integer ((Rel_Time - Duration (timeval.tv_sec)) * 10#1#E6);
106
107            C_select (timeout => timeval'Unchecked_Access);
108            Check_Time := Clock;
109
110            exit when Abs_Time <= Check_Time or else Check_Time < Base_Time;
111
112            Rel_Time := Abs_Time - Check_Time;
113         end loop;
114      end if;
115   end Timed_Delay;
116
117   ----------------
118   -- Initialize --
119   ----------------
120
121   procedure Initialize is
122   begin
123      null;
124   end Initialize;
125
126end System.OS_Primitives;
127