gcc/ada/s-osprim-posix.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) 1998-2009, 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
  34 package 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 struct_timezone is record
  42       tz_minuteswest  : Integer;
  43       tz_dsttime   : Integer;
  44    end record;
  45    pragma Convention (C, struct_timezone);
  46    type struct_timezone_ptr is access all struct_timezone;
  47
  48    type time_t is new Long_Integer;
  49
  50    type struct_timeval is record
  51       tv_sec       : time_t;
  52       tv_usec      : Long_Integer;
  53    end record;
  54    pragma Convention (C, struct_timeval);
  55
  56    function gettimeofday
  57      (tv : not null access struct_timeval;
  58       tz : struct_timezone_ptr) return Integer;
  59    pragma Import (C, gettimeofday, "gettimeofday");
  60
  61    type timespec is record
  62       tv_sec  : time_t;
  63       tv_nsec : Long_Integer;
  64    end record;
  65    pragma Convention (C, timespec);
  66
  67    function nanosleep (rqtp, rmtp : not null access timespec) return Integer;
  68    pragma Import (C, nanosleep, "nanosleep");
  69
  70    -----------
  71    -- Clock --
  72    -----------
  73
  74    function Clock return Duration is
  75       TV     : aliased struct_timeval;
  76
  77       Result : Integer;
  78       pragma Unreferenced (Result);
  79
  80    begin
  81       --  The return codes for gettimeofday are as follows (from man pages):
  82       --    EPERM  settimeofday is called by someone other than the superuser
  83       --    EINVAL Timezone (or something else) is invalid
  84       --    EFAULT One of tv or tz pointed outside accessible address space
  85
  86       --  None of these codes signal a potential clock skew, hence the return
  87       --  value is never checked.
  88
  89       Result := gettimeofday (TV'Access, null);
  90       return Duration (TV.tv_sec) + Duration (TV.tv_usec) / 10#1#E6;
  91    end Clock;
  92
  93    ---------------------
  94    -- Monotonic_Clock --
  95    ---------------------
  96
  97    function Monotonic_Clock return Duration renames Clock;
  98
  99    -----------------
 100    -- To_Timespec --
 101    -----------------
 102
 103    function To_Timespec (D : Duration) return timespec;
 104
 105    function To_Timespec (D : Duration) return timespec is
 106       S : time_t;
 107       F : Duration;
 108
 109    begin
 110       S := time_t (Long_Long_Integer (D));
 111       F := D - Duration (S);
 112
 113       --  If F has negative value due to a round-up, adjust for positive F
 114       --  value.
 115
 116       if F < 0.0 then
 117          S := S - 1;
 118          F := F + 1.0;
 119       end if;
 120
 121       return
 122         timespec'(tv_sec  => S,
 123                   tv_nsec => Long_Integer (Long_Long_Integer (F * 10#1#E9)));
 124    end To_Timespec;
 125
 126    -----------------
 127    -- Timed_Delay --
 128    -----------------
 129
 130    procedure Timed_Delay
 131      (Time : Duration;
 132       Mode : Integer)
 133    is
 134       Request    : aliased timespec;
 135       Remaind    : aliased timespec;
 136       Rel_Time   : Duration;
 137       Abs_Time   : Duration;
 138       Base_Time  : constant Duration := Clock;
 139       Check_Time : Duration := Base_Time;
 140
 141       Result : Integer;
 142       pragma Unreferenced (Result);
 143
 144    begin
 145       if Mode = Relative then
 146          Rel_Time := Time;
 147          Abs_Time := Time + Check_Time;
 148       else
 149          Rel_Time := Time - Check_Time;
 150          Abs_Time := Time;
 151       end if;
 152
 153       if Rel_Time > 0.0 then
 154          loop
 155             Request := To_Timespec (Rel_Time);
 156             Result := nanosleep (Request'Access, Remaind'Access);
 157             Check_Time := Clock;
 158
 159             exit when Abs_Time <= Check_Time or else Check_Time < Base_Time;
 160
 161             Rel_Time := Abs_Time - Check_Time;
 162          end loop;
 163       end if;
 164    end Timed_Delay;
 165
 166    ----------------
 167    -- Initialize --
 168    ----------------
 169
 170    procedure Initialize is
 171    begin
 172       null;
 173    end Initialize;
 174
 175 end System.OS_Primitives;