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 --                             $Revision: 1.8 $
  10 --                                                                          --
  11 --          Copyright (C) 1998-2001 Free Software Foundation, Inc.          --
  12 --                                                                          --
  13 -- GNARL is free software; you can  redistribute it  and/or modify it under --
  14 -- terms of the  GNU General Public License as published  by the Free Soft- --
  15 -- ware  Foundation;  either version 2,  or (at your option) any later ver- --
  16 -- sion. GNARL is distributed in the hope that it will be useful, but WITH- --
  17 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  18 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  19 -- for  more details.  You should have  received  a copy of the GNU General --
  20 -- Public License  distributed with GNARL; see file COPYING.  If not, write --
  21 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  22 -- MA 02111-1307, USA.                                                      --
  23 --                                                                          --
  24 -- As a special exception,  if other files  instantiate  generics from this --
  25 -- unit, or you link  this unit with other files  to produce an executable, --
  26 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  27 -- covered  by the  GNU  General  Public  License.  This exception does not --
  28 -- however invalidate  any other reasons why  the executable file  might be --
  29 -- covered by the  GNU Public License.                                      --
  30 --                                                                          --
  31 -- GNARL was developed by the GNARL team at Florida State University. It is --
  32 -- now maintained by Ada Core Technologies Inc. in cooperation with Florida --
  33 -- State University (http://www.gnat.com).                                  --
  34 --                                                                          --
  35 ------------------------------------------------------------------------------
  36
  37 --  This version uses gettimeofday and select
  38 --  Currently OpenNT, Dec Unix, Solaris and SCO UnixWare use this file.
  39
  40 package body System.OS_Primitives is
  41
  42    --  ??? These definitions are duplicated from System.OS_Interface
  43    --  because we don't want to depend on any package. Consider removing
  44    --  these declarations in System.OS_Interface and move these ones in
  45    --  the spec.
  46
  47    type struct_timezone is record
  48       tz_minuteswest  : Integer;
  49       tz_dsttime   : Integer;
  50    end record;
  51    pragma Convention (C, struct_timezone);
  52    type struct_timezone_ptr is access all struct_timezone;
  53
  54    type struct_timeval is record
  55       tv_sec       : Integer;
  56       tv_usec      : Integer;
  57    end record;
  58    pragma Convention (C, struct_timeval);
  59
  60    function gettimeofday
  61      (tv : access struct_timeval;
  62       tz : struct_timezone_ptr) return Integer;
  63    pragma Import (C, gettimeofday, "gettimeofday");
  64
  65    type fd_set is null record;
  66    type fd_set_ptr is access all fd_set;
  67
  68    function C_select
  69      (n         : Integer    := 0;
  70       readfds,
  71       writefds,
  72       exceptfds : fd_set_ptr := null;
  73       timeout   : access struct_timeval) return Integer;
  74    pragma Import (C, C_select, "select");
  75
  76    -----------
  77    -- Clock --
  78    -----------
  79
  80    function Clock return Duration is
  81       TV     : aliased struct_timeval;
  82       Result : Integer;
  83
  84    begin
  85       Result := gettimeofday (TV'Access, null);
  86       return Duration (TV.tv_sec) + Duration (TV.tv_usec) / 10#1#E6;
  87    end Clock;
  88
  89    ---------------------
  90    -- Monotonic_Clock --
  91    ---------------------
  92
  93    function Monotonic_Clock return Duration renames Clock;
  94
  95    -----------------
  96    -- Timed_Delay --
  97    -----------------
  98
  99    procedure Timed_Delay
 100      (Time : Duration;
 101       Mode : Integer)
 102    is
 103       Result     : Integer;
 104       Rel_Time   : Duration;
 105       Abs_Time   : Duration;
 106       Check_Time : Duration := Clock;
 107       timeval    : aliased struct_timeval;
 108
 109    begin
 110       if Mode = Relative then
 111          Rel_Time := Time;
 112          Abs_Time := Time + Check_Time;
 113       else
 114          Rel_Time := Time - Check_Time;
 115          Abs_Time := Time;
 116       end if;
 117
 118       if Rel_Time > 0.0 then
 119          loop
 120             timeval.tv_sec := Integer (Rel_Time);
 121
 122             if Duration (timeval.tv_sec) > Rel_Time then
 123                timeval.tv_sec := timeval.tv_sec - 1;
 124             end if;
 125
 126             timeval.tv_usec :=
 127               Integer ((Rel_Time - Duration (timeval.tv_sec)) * 10#1#E6);
 128
 129             Result := C_select (timeout => timeval'Unchecked_Access);
 130             Check_Time := Clock;
 131
 132             exit when Abs_Time <= Check_Time;
 133
 134             Rel_Time := Abs_Time - Check_Time;
 135          end loop;
 136       end if;
 137    end Timed_Delay;
 138
 139 end System.OS_Primitives;