gcc/ada/5posprim.adb

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                GNU ADA 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 --                                                                          --
  10 --          Copyright (C) 1998-2001 Free Software Foundation, Inc.          --
  11 --                                                                          --
  12 -- GNARL is free software; you can  redistribute it  and/or modify it under --
  13 -- terms of the  GNU General Public License as published  by the Free Soft- --
  14 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  15 -- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
  16 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  17 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  18 -- for  more details.  You should have  received  a copy of the GNU General --
  19 -- Public License  distributed with GNARL; see file COPYING.  If not, write --
  20 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  21 -- MA 02111-1307, USA.                                                      --
  22 --                                                                          --
  23 -- As a special exception,  if other files  instantiate  generics from this --
  24 -- unit, or you link  this unit with other files  to produce an executable, --
  25 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  26 -- covered  by the  GNU  General  Public  License.  This exception does not --
  27 -- however invalidate  any other reasons why  the executable file  might be --
  28 -- covered by the  GNU Public License.                                      --
  29 --                                                                          --
  30 -- GNARL was developed by the GNARL team at Florida State University. It is --
  31 -- now maintained by Ada Core Technologies Inc. in cooperation with Florida --
  32 -- State University (http://www.gnat.com).                                  --
  33 --                                                                          --
  34 ------------------------------------------------------------------------------
  35
  36 --  This version uses gettimeofday and select
  37 --  Currently OpenNT, Dec Unix, Solaris and SCO UnixWare use this file.
  38
  39 package body System.OS_Primitives is
  40
  41    --  ??? These definitions are duplicated from System.OS_Interface
  42    --  because we don't want to depend on any package. Consider removing
  43    --  these declarations in System.OS_Interface and move these ones in
  44    --  the spec.
  45
  46    type struct_timezone is record
  47       tz_minuteswest  : Integer;
  48       tz_dsttime   : Integer;
  49    end record;
  50    pragma Convention (C, struct_timezone);
  51    type struct_timezone_ptr is access all struct_timezone;
  52
  53    type struct_timeval is record
  54       tv_sec       : Integer;
  55       tv_usec      : Integer;
  56    end record;
  57    pragma Convention (C, struct_timeval);
  58
  59    function gettimeofday
  60      (tv : access struct_timeval;
  61       tz : struct_timezone_ptr) return Integer;
  62    pragma Import (C, gettimeofday, "gettimeofday");
  63
  64    type fd_set is null record;
  65    type fd_set_ptr is access all fd_set;
  66
  67    function C_select
  68      (n         : Integer    := 0;
  69       readfds,
  70       writefds,
  71       exceptfds : fd_set_ptr := null;
  72       timeout   : access struct_timeval) return Integer;
  73    pragma Import (C, C_select, "select");
  74
  75    -----------
  76    -- Clock --
  77    -----------
  78
  79    function Clock return Duration is
  80       TV     : aliased struct_timeval;
  81       Result : Integer;
  82
  83    begin
  84       Result := gettimeofday (TV'Access, null);
  85       return Duration (TV.tv_sec) + Duration (TV.tv_usec) / 10#1#E6;
  86    end Clock;
  87
  88    ---------------------
  89    -- Monotonic_Clock --
  90    ---------------------
  91
  92    function Monotonic_Clock return Duration renames Clock;
  93
  94    -----------------
  95    -- Timed_Delay --
  96    -----------------
  97
  98    procedure Timed_Delay
  99      (Time : Duration;
 100       Mode : Integer)
 101    is
 102       Result     : Integer;
 103       Rel_Time   : Duration;
 104       Abs_Time   : Duration;
 105       Check_Time : Duration := Clock;
 106       timeval    : aliased struct_timeval;
 107
 108    begin
 109       if Mode = Relative then
 110          Rel_Time := Time;
 111          Abs_Time := Time + Check_Time;
 112       else
 113          Rel_Time := Time - Check_Time;
 114          Abs_Time := Time;
 115       end if;
 116
 117       if Rel_Time > 0.0 then
 118          loop
 119             timeval.tv_sec := Integer (Rel_Time);
 120
 121             if Duration (timeval.tv_sec) > Rel_Time then
 122                timeval.tv_sec := timeval.tv_sec - 1;
 123             end if;
 124
 125             timeval.tv_usec :=
 126               Integer ((Rel_Time - Duration (timeval.tv_sec)) * 10#1#E6);
 127
 128             Result := C_select (timeout => timeval'Unchecked_Access);
 129             Check_Time := Clock;
 130
 131             exit when Abs_Time <= Check_Time;
 132
 133             Rel_Time := Abs_Time - Check_Time;
 134          end loop;
 135       end if;
 136    end Timed_Delay;
 137
 138 end System.OS_Primitives;