------------------------------------------------------------------------------
-- --
--- GNU ADA RUN-TIME LIBRARY (GNARL) COMPONENTS --
+-- GNAT RUN-TIME LIBRARY (GNARL) COMPONENTS --
-- --
-- S Y S T E M . O S _ P R I M I T I V E S --
-- --
--- B o d y --
+-- B o d y --
-- --
--- Copyright (C) 1998-2003 Free Software Foundation, Inc. --
+-- Copyright (C) 1998-2007, Free Software Foundation, Inc. --
-- --
-- GNARL is free software; you can redistribute it and/or modify it under --
-- terms of the GNU General Public License as published by the Free Soft- --
-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
-- for more details. You should have received a copy of the GNU General --
-- Public License distributed with GNARL; see file COPYING. If not, write --
--- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
--- MA 02111-1307, USA. --
+-- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
+-- Boston, MA 02110-1301, USA. --
-- --
-- As a special exception, if other files instantiate generics from this --
-- unit, or you link this unit with other files to produce an executable, --
-- This is the NT version of this package
-with Ada.Exceptions;
with Interfaces.C;
package body System.OS_Primitives is
type BOOL is new Boolean;
for BOOL'Size use Interfaces.C.unsigned_long'Size;
- procedure GetSystemTimeAsFileTime (lpFileTime : access Long_Long_Integer);
+ procedure GetSystemTimeAsFileTime
+ (lpFileTime : not null access Long_Long_Integer);
pragma Import (Stdcall, GetSystemTimeAsFileTime, "GetSystemTimeAsFileTime");
function QueryPerformanceCounter
- (lpPerformanceCount : access LARGE_INTEGER) return BOOL;
+ (lpPerformanceCount : not null access LARGE_INTEGER) return BOOL;
pragma Import
(Stdcall, QueryPerformanceCounter, "QueryPerformanceCounter");
function QueryPerformanceFrequency
- (lpFrequency : access LARGE_INTEGER) return BOOL;
+ (lpFrequency : not null access LARGE_INTEGER) return BOOL;
pragma Import
(Stdcall, QueryPerformanceFrequency, "QueryPerformanceFrequency");
-- GNU/Linker will fail to auto-import those variables when building
-- libgnarl.dll. The indirection level introduced here has no measurable
-- penalties.
- --
+
-- Note that access variables below must not be declared as constant
-- otherwise the compiler optimization will remove this indirect access.
Base_Ticks : aliased LARGE_INTEGER;
BTA : constant LIA := Base_Ticks'Access;
- -- Holds the Tick count for the base time.
+ -- Holds the Tick count for the base time
Base_Monotonic_Ticks : aliased LARGE_INTEGER;
BMTA : constant LIA := Base_Monotonic_Ticks'Access;
-- If we have a shift of more than Max_Shift seconds we resynchonize the
-- Clock. This is probably due to a manual Clock adjustment, an DST
- -- adjustment or an NTP synchronisation. And we want to adjust the
- -- time for this system (non-monotonic) clock.
+ -- adjustment or an NTP synchronisation. And we want to adjust the time
+ -- for this system (non-monotonic) clock.
if abs (Elap_Secs_Sys - Elap_Secs_Tick) > Max_Shift then
Get_Base_Time;
-------------------
procedure Get_Base_Time is
- -- The resolution for GetSystemTime is 1 millisecond.
+
+ -- The resolution for GetSystemTime is 1 millisecond
-- The time to get both base times should take less than 1 millisecond.
-- Therefore, the elapsed time reported by GetSystemTime between both
-- actions should be null.
- Max_Elapsed : constant := 0;
+ Max_Elapsed : constant := 0;
- Test_Now : aliased Long_Long_Integer;
+ Test_Now : aliased Long_Long_Integer;
epoch_1970 : constant := 16#19D_B1DE_D53E_8000#; -- win32 UTC epoch
system_time_ns : constant := 100; -- 100 ns per tick
function Monotonic_Clock return Duration is
Current_Ticks : aliased LARGE_INTEGER;
Elap_Secs_Tick : Duration;
+
begin
if not QueryPerformanceCounter (Current_Ticks'Access) then
return 0.0;
-----------------
procedure Timed_Delay (Time : Duration; Mode : Integer) is
+
+ function Mode_Clock return Duration;
+ pragma Inline (Mode_Clock);
+ -- Return the current clock value using either the monotonic clock or
+ -- standard clock depending on the Mode value.
+
+ ----------------
+ -- Mode_Clock --
+ ----------------
+
+ function Mode_Clock return Duration is
+ begin
+ case Mode is
+ when Absolute_RT =>
+ return Monotonic_Clock;
+ when others =>
+ return Clock;
+ end case;
+ end Mode_Clock;
+
+ -- Local Variables
+
+ Base_Time : constant Duration := Mode_Clock;
+ -- Base_Time is used to detect clock set backward, in this case we
+ -- cannot ensure the delay accuracy.
+
Rel_Time : Duration;
Abs_Time : Duration;
- Check_Time : Duration := Monotonic_Clock;
+ Check_Time : Duration := Base_Time;
+
+ -- Start of processing for Timed Delay
begin
if Mode = Relative then
if Rel_Time > 0.0 then
loop
Sleep (DWORD (Rel_Time * 1000.0));
- Check_Time := Monotonic_Clock;
+ Check_Time := Mode_Clock;
- exit when Abs_Time <= Check_Time;
+ exit when Abs_Time <= Check_Time or else Check_Time < Base_Time;
Rel_Time := Abs_Time - Check_Time;
end loop;
end if;
end Timed_Delay;
--- Package elaboration, get starting time as base
+ ----------------
+ -- Initialize --
+ ----------------
+
+ Initialized : Boolean := False;
+
+ procedure Initialize is
+ begin
+ if Initialized then
+ return;
+ end if;
+
+ Initialized := True;
+
+ -- Get starting time as base
+
+ if not QueryPerformanceFrequency (Tick_Frequency'Access) then
+ raise Program_Error
+ with "cannot get high performance counter frequency";
+ end if;
-begin
- if not QueryPerformanceFrequency (Tick_Frequency'Access) then
- Ada.Exceptions.Raise_Exception
- (Program_Error'Identity,
- "cannot get high performance counter frequency");
- end if;
+ Get_Base_Time;
- Get_Base_Time;
+ -- Keep base clock and ticks for the monotonic clock. These values
+ -- should never be changed to ensure proper behavior of the monotonic
+ -- clock.
- -- Keep base clock and ticks for the monotonic clock. These values should
- -- never be changed to ensure proper behavior of the monotonic clock.
+ Base_Monotonic_Clock := Base_Clock;
+ Base_Monotonic_Ticks := Base_Ticks;
+ end Initialize;
- Base_Monotonic_Clock := Base_Clock;
- Base_Monotonic_Ticks := Base_Ticks;
end System.OS_Primitives;
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