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|
-- C960002.A
--
-- Grant of Unlimited Rights
--
-- Under contracts F33600-87-D-0337, F33600-84-D-0280, MDA903-79-C-0687,
-- F08630-91-C-0015, and DCA100-97-D-0025, the U.S. Government obtained
-- unlimited rights in the software and documentation contained herein.
-- Unlimited rights are defined in DFAR 252.227-7013(a)(19). By making
-- this public release, the Government intends to confer upon all
-- recipients unlimited rights equal to those held by the Government.
-- These rights include rights to use, duplicate, release or disclose the
-- released technical data and computer software in whole or in part, in
-- any manner and for any purpose whatsoever, and to have or permit others
-- to do so.
--
-- DISCLAIMER
--
-- ALL MATERIALS OR INFORMATION HEREIN RELEASED, MADE AVAILABLE OR
-- DISCLOSED ARE AS IS. THE GOVERNMENT MAKES NO EXPRESS OR IMPLIED
-- WARRANTY AS TO ANY MATTER WHATSOEVER, INCLUDING THE CONDITIONS OF THE
-- SOFTWARE, DOCUMENTATION OR OTHER INFORMATION RELEASED, MADE AVAILABLE
-- OR DISCLOSED, OR THE OWNERSHIP, MERCHANTABILITY, OR FITNESS FOR A
-- PARTICULAR PURPOSE OF SAID MATERIAL.
--*
--
-- OBJECTIVE:
-- Check that the simple "delay until" when the request time is "now" and
-- also some time already in the past is obeyed and returns immediately
--
-- TEST DESCRIPTION:
-- Simulate a task that sends a "pulse" at regular intervals. The Delay
-- Until statement is used to avoid accumulated drift. In this test
-- three simple situations simulating the start of drift are used: the
-- next pulse being called for at the normal time, the next pulse being
-- called for at exactly the current time and then at some time which has
-- already past. We assume the delay is within a While Loop and, to
-- simplify the test, we "unfold" the While Loop and execute the Delays
-- in a serial fashion. This loop is shown in test C960001.
-- It is not possible to test the actual immediacy of the expiration. We
-- can only check that it returns in a "reasonable" time. In this case
-- we check that it expires before the next "pulse" should have been
-- issued.
--
--
-- CHANGE HISTORY:
-- 06 Dec 94 SAIC ACVC 2.0
--
--!
with Report;
with ImpDef;
with Ada.Calendar;
with System;
procedure C960002 is
begin
Report.Test ("C960002", "Simple Delay Until with requested time being" &
" ""now"" and time already in the past");
declare -- To get the Report.Result after all has completed
function "+" (Left : Ada.Calendar.Time; Right: Duration)
return Ada.Calendar.Time renames Ada.Calendar."+";
function "-" (Left : Ada.Calendar.Time; Right: Duration)
return Ada.Calendar.Time renames Ada.Calendar."-";
function "-" (Left, Right : Ada.Calendar.Time)
return duration renames Ada.Calendar."-";
function ">" (Left, Right : Ada.Calendar.Time)
return Boolean renames Ada.Calendar.">";
task Pulse_Task is
entry Trigger;
end Pulse_Task;
-- Task to synchronize all qualified receivers.
-- The entry Trigger starts the synchronization.
--
task body Pulse_Task is
Pulse_Time : Ada.Calendar.Time;
Pulse_Time_Delta : constant duration := ImpDef.Clear_Ready_Queue;
TC_Time_Back : Ada.Calendar.Time;
-- This routine transmits a synchronizing "pulse" to
-- all receivers
procedure Pulse is
begin
null; -- Stub
Report.Comment (".......PULSE........");
end Pulse;
begin
accept Trigger;
Pulse;
---------------
-- normal calculation for "next"
Pulse_Time := Ada.Calendar.Clock + Pulse_Time_Delta;
-- TC: unfold the "while" loop in C960001. Four passes through
-- the loop are shown
delay until Pulse_Time;
Pulse;
---------------
-- TC: the normal calculation for "next" would be
-- Pulse_Time := Pulse_Time + Pulse_Time_Delta;
-- Instead of this normal pulse time calculation simulate
-- the new pulse time to be exactly "now" (or, as exactly as
-- we can)
Pulse_Time := Ada.Calendar.Clock;
delay until Ada.Calendar.Clock;
TC_Time_Back := Ada.Calendar.Clock;
-- Now check for reasonableness
if TC_Time_Back > Pulse_Time + Pulse_Time_Delta then
Report.Failed
("""Now"" delayed for more than Pulse_Time_Delta - A");
end if;
Pulse;
---------------
-- normal calculation for "next" would be
Pulse_Time := Pulse_Time + Pulse_Time_Delta;
-- TC: Instead of this, simulate the new calculated pulse time
-- being already past
Pulse_Time := Ada.Calendar.Clock - System.Tick;
delay until Pulse_Time;
TC_Time_Back := Ada.Calendar.Clock;
-- Now check for reasonableness
if TC_Time_Back > Pulse_Time + Pulse_Time_Delta then
Report.Failed
("""Now"" delayed for more than Pulse_Time_Delta - B");
end if;
Pulse;
---------------
-- normal calculation for "next"
Pulse_Time := Pulse_Time + Pulse_Time_Delta;
-- Now simulate getting back into synch
delay until Pulse_Time;
Pulse;
---------------
-- This would be the end of the "while" loop
exception
when others =>
Report.Failed ("Unexpected exception in Pulse_Task");
end Pulse_Task;
begin -- declare
Pulse_Task.Trigger; -- Start test
end; -- declare
Report.Result;
end C960002;
|
