gcc/ada/s-osprim-unix.adb

   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) 1998-2007, 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 2,  or (at your option) any later ver- --
  14 -- sion. GNARL 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.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNARL; see file COPYING.  If not, write --
  19 -- to  the  Free Software Foundation,  51  Franklin  Street,  Fifth  Floor, --
  20 -- Boston, MA 02110-1301, USA.                                              --
  21 --                                                                          --
  22 -- As a special exception,  if other files  instantiate  generics from this --
  23 -- unit, or you link  this unit with other files  to produce an executable, --
  24 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  25 -- covered  by the  GNU  General  Public  License.  This exception does not --
  26 -- however invalidate  any other reasons why  the executable file  might be --
  27 -- covered by the  GNU Public License.                                      --
  28 --                                                                          --
  29 -- GNARL was developed by the GNARL team at Florida State University.       --
  30 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 --  This version uses gettimeofday and select
  35 --  This file is suitable for OpenNT, Dec Unix and SCO UnixWare.
  36
  37 package body System.OS_Primitives is
  38
  39    --  ??? These definitions are duplicated from System.OS_Interface
  40    --  because we don't want to depend on any package. Consider removing
  41    --  these declarations in System.OS_Interface and move these ones in
  42    --  the spec.
  43
  44    type struct_timeval is record
  45       tv_sec  : Integer;
  46       tv_usec : Integer;
  47    end record;
  48    pragma Convention (C, struct_timeval);
  49
  50    procedure gettimeofday
  51      (tv : not null access struct_timeval;
  52       tz : Address := Null_Address);
  53    pragma Import (C, gettimeofday, "gettimeofday");
  54
  55    procedure C_select
  56      (n         : Integer := 0;
  57       readfds,
  58       writefds,
  59       exceptfds : Address := Null_Address;
  60       timeout   : not null access struct_timeval);
  61    pragma Import (C, C_select, "select");
  62
  63    -----------
  64    -- Clock --
  65    -----------
  66
  67    function Clock return Duration is
  68       TV : aliased struct_timeval;
  69
  70    begin
  71       gettimeofday (TV'Access);
  72       return Duration (TV.tv_sec) + Duration (TV.tv_usec) / 10#1#E6;
  73    end Clock;
  74
  75    ---------------------
  76    -- Monotonic_Clock --
  77    ---------------------
  78
  79    function Monotonic_Clock return Duration renames Clock;
  80
  81    -----------------
  82    -- Timed_Delay --
  83    -----------------
  84
  85    procedure Timed_Delay
  86      (Time : Duration;
  87       Mode : Integer)
  88    is
  89       Rel_Time   : Duration;
  90       Abs_Time   : Duration;
  91       Base_Time  : constant Duration := Clock;
  92       Check_Time : Duration := Base_Time;
  93       timeval    : aliased struct_timeval;
  94
  95    begin
  96       if Mode = Relative then
  97          Rel_Time := Time;
  98          Abs_Time := Time + Check_Time;
  99       else
 100          Rel_Time := Time - Check_Time;
 101          Abs_Time := Time;
 102       end if;
 103
 104       if Rel_Time > 0.0 then
 105          loop
 106             timeval.tv_sec := Integer (Rel_Time);
 107
 108             if Duration (timeval.tv_sec) > Rel_Time then
 109                timeval.tv_sec := timeval.tv_sec - 1;
 110             end if;
 111
 112             timeval.tv_usec :=
 113               Integer ((Rel_Time - Duration (timeval.tv_sec)) * 10#1#E6);
 114
 115             C_select (timeout => timeval'Unchecked_Access);
 116             Check_Time := Clock;
 117
 118             exit when Abs_Time <= Check_Time or else Check_Time < Base_Time;
 119
 120             Rel_Time := Abs_Time - Check_Time;
 121          end loop;
 122       end if;
 123    end Timed_Delay;
 124
 125    ----------------
 126    -- Initialize --
 127    ----------------
 128
 129    procedure Initialize is
 130    begin
 131       null;
 132    end Initialize;
 133
 134 end System.OS_Primitives;