Symbian3/Examples/guid-6013a680-57f9-415b-8851-c4fa63356636/_periodic_8cpp-source.html
Week 12 contribution of SDK documentation_content. See release notes for details. Fixes Bug 1892, Bug 1522, Bug 1520, Bug 394, Bug 1319, Bug 344, Bug 1897
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<h1>examples/Base/Timers/Periodic/Periodic.cpp</h1><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">// Copyright (c) 2000-2009 Nokia Corporation and/or its subsidiary(-ies).</span>
<a name="l00002"></a>00002 <span class="comment">// All rights reserved.</span>
<a name="l00003"></a>00003 <span class="comment">// This component and the accompanying materials are made available</span>
<a name="l00004"></a>00004 <span class="comment">// under the terms of "Eclipse Public License v1.0"</span>
<a name="l00005"></a>00005 <span class="comment">// which accompanies this distribution, and is available</span>
<a name="l00006"></a>00006 <span class="comment">// at the URL "http://www.eclipse.org/legal/epl-v10.html".</span>
<a name="l00007"></a>00007 <span class="comment">//</span>
<a name="l00008"></a>00008 <span class="comment">// Initial Contributors:</span>
<a name="l00009"></a>00009 <span class="comment">// Nokia Corporation - initial contribution.</span>
<a name="l00010"></a>00010 <span class="comment">//</span>
<a name="l00011"></a>00011 <span class="comment">// Contributors:</span>
<a name="l00012"></a>00012 <span class="comment">//</span>
<a name="l00013"></a>00013 <span class="comment">// Description:</span>
<a name="l00014"></a>00014 <span class="comment">// Shows difference between CPeriodic and CHeartBeat</span>
<a name="l00015"></a>00015 <span class="comment">// CPeriodic uses repeated RTimer::After() requests to get</span>
<a name="l00016"></a>00016 <span class="comment">// a periodic tick - simple, but the time the tick is serviced lags</span>
<a name="l00017"></a>00017 <span class="comment">// increasingly.</span>
<a name="l00018"></a>00018 <span class="comment">// As a nuance of CPeriodic, it takes a TCallBack to service</span>
<a name="l00019"></a>00019 <span class="comment">// its requests.</span>
<a name="l00020"></a>00020 <span class="comment">// CHeartbeat uses repeated RTimer::Lock() requests: its</span>
<a name="l00021"></a>00021 <span class="comment">// requests complete in synchronization with the beating</span>
<a name="l00022"></a>00022 <span class="comment">// of the system clock.</span>
<a name="l00023"></a>00023 <span class="comment">// As a nuance of CHeartbeat, it takes an MBeating* mixin:</span>
<a name="l00024"></a>00024 <span class="comment">// the MBeating's Beat() function is called when completion</span>
<a name="l00025"></a>00025 <span class="comment">// occurs in sync, and Synchronize() is called when</span>
<a name="l00026"></a>00026 <span class="comment">// synchronization has been lost.</span>
<a name="l00027"></a>00027 <span class="comment">//</span>
<a name="l00028"></a>00028
<a name="l00029"></a>00029
<a name="l00030"></a>00030
<a name="l00031"></a>00031 <span class="comment">// standard example header</span>
<a name="l00032"></a>00032 <span class="preprocessor">#include "CommonFramework.h"</span>
<a name="l00033"></a>00033
<a name="l00034"></a>00034 <span class="comment">// beginning of real example</span>
<a name="l00035"></a>00035
<a name="l00036"></a>00036 <span class="preprocessor">#include <e32math.h></span>
<a name="l00037"></a>00037
<a name="l00038"></a>00038 <span class="keywordtype">void</span> RandomDelay(TInt64& aSeed, TInt <span class="comment">/*aTimerNumber*/</span>)
<a name="l00039"></a>00039 {
<a name="l00040"></a>00040 <span class="comment">// initialize seed first time through</span>
<a name="l00041"></a>00041 <span class="keywordflow">if</span> (aSeed==0)
<a name="l00042"></a>00042 {
<a name="l00043"></a>00043 TTime time;
<a name="l00044"></a>00044 time.HomeTime();
<a name="l00045"></a>00045 aSeed=time.Int64();
<a name="l00046"></a>00046 }
<a name="l00047"></a>00047 <span class="comment">// ok, here we go</span>
<a name="l00048"></a>00048 TReal randomZeroToOne;
<a name="l00049"></a>00049 randomZeroToOne = Math::FRand(aSeed);
<a name="l00050"></a>00050 TReal realDelay;
<a name="l00051"></a>00051 realDelay = randomZeroToOne * randomZeroToOne * 2000000;
<a name="l00052"></a>00052 TInt32 intDelay;
<a name="l00053"></a>00053 Math::Int(intDelay, realDelay);
<a name="l00054"></a>00054 TTimeIntervalMicroSeconds32 delayMicroSeconds;
<a name="l00055"></a>00055 delayMicroSeconds=intDelay;
<a name="l00056"></a>00056 User::After(delayMicroSeconds);
<a name="l00057"></a>00057 }
<a name="l00058"></a>00058
<a name="l00059"></a>00059 <span class="comment">// A version of the RandomDelay function which is not random ! </span>
<a name="l00060"></a>00060 <span class="comment">// The delay is fixed at 1000000us and may be useful to </span>
<a name="l00061"></a>00061 <span class="comment">// experiment with. </span>
<a name="l00062"></a>00062 <span class="comment">//</span>
<a name="l00063"></a>00063 <span class="comment">//</span>
<a name="l00064"></a>00064 <span class="comment">//void RandomDelay(TInt64& /* aSeed */, TInt aTimerNumber)</span>
<a name="l00065"></a>00065 <span class="comment">// {</span>
<a name="l00066"></a>00066 <span class="comment">// User::After(1000000);</span>
<a name="l00067"></a>00067 <span class="comment">// _LIT(KFormatMisc,"Delay for timer %d: 1000000us\n");</span>
<a name="l00068"></a>00068 <span class="comment">// console->Printf(KFormatMisc, aTimerNumber);</span>
<a name="l00069"></a>00069 <span class="comment">// }</span>
<a name="l00070"></a>00070
<a name="l00071"></a>00071
<a name="l00072"></a>00072 <span class="keyword">class </span>TAppRunner
<a name="l00073"></a>00073 {
<a name="l00074"></a>00074 <span class="keyword">public</span>:
<a name="l00075"></a>00075 TAppRunner();
<a name="l00076"></a>00076 <span class="keywordtype">void</span> NotifyFinished(); <span class="comment">// notify an active object has finished</span>
<a name="l00077"></a>00077 <span class="keywordtype">void</span> NotifyStarted(); <span class="comment">// notify an active object has started</span>
<a name="l00078"></a>00078 <span class="comment">// private:</span>
<a name="l00079"></a>00079 TInt iActiveObjects; <span class="comment">// count of active objects</span>
<a name="l00080"></a>00080 };
<a name="l00081"></a>00081
<a name="l00082"></a>00082 TAppRunner::TAppRunner()
<a name="l00083"></a>00083 {
<a name="l00084"></a>00084 iActiveObjects=0;
<a name="l00085"></a>00085 }
<a name="l00086"></a>00086
<a name="l00087"></a>00087 <span class="keywordtype">void</span> TAppRunner::NotifyStarted()
<a name="l00088"></a>00088 {
<a name="l00089"></a>00089 iActiveObjects++;
<a name="l00090"></a>00090 }
<a name="l00091"></a>00091
<a name="l00092"></a>00092 <span class="keywordtype">void</span> TAppRunner::NotifyFinished()
<a name="l00093"></a>00093 {
<a name="l00094"></a>00094 iActiveObjects--;
<a name="l00095"></a>00095 <span class="keywordflow">if</span> (iActiveObjects==0) CActiveScheduler::Stop();
<a name="l00096"></a>00096 }
<a name="l00097"></a>00097
<a name="l00098"></a>00098 <span class="comment">/*</span>
<a name="l00099"></a>00099 <span class="comment"> CPeriodicRunner class</span>
<a name="l00100"></a>00100 <span class="comment"></span>
<a name="l00101"></a>00101 <span class="comment"> Constructor makes a CPeriodic and sets it off with one-second ticks.</span>
<a name="l00102"></a>00102 <span class="comment"> These are fielded by the callback function, the static Tick(TAny*),</span>
<a name="l00103"></a>00103 <span class="comment"> which simply casts the pointer to a CPeriodicRunner* and calls</span>
<a name="l00104"></a>00104 <span class="comment"> the non-static callback, DoTick().</span>
<a name="l00105"></a>00105 <span class="comment"></span>
<a name="l00106"></a>00106 <span class="comment"> Processing gets behind: when the ticks left have counted down to zero,</span>
<a name="l00107"></a>00107 <span class="comment"> it should be behind by a second or two. The destructor indicates how many</span>
<a name="l00108"></a>00108 <span class="comment"> seconds since the object's creation.</span>
<a name="l00109"></a>00109 <span class="comment">*/</span>
<a name="l00110"></a>00110
<a name="l00111"></a>00111 <span class="keyword">class </span>CPeriodicRunner : <span class="keyword">public</span> CBase
<a name="l00112"></a>00112 {
<a name="l00113"></a>00113 <span class="keyword">public</span>:
<a name="l00114"></a>00114 <span class="comment">// construct, add CPeriodic to active scheduler, and start it</span>
<a name="l00115"></a>00115 <span class="keyword">static</span> CPeriodicRunner* NewL(TInt aTickInterval, TInt aTotalTicks, TAppRunner& aAppRunner);
<a name="l00116"></a>00116 ~CPeriodicRunner(); <span class="comment">// destruct and give statistics</span>
<a name="l00117"></a>00117 <span class="keyword">protected</span>:
<a name="l00118"></a>00118 CPeriodicRunner(TInt aTickInterval, TInt aTotalTicks, TAppRunner& aAppRunner);
<a name="l00119"></a>00119 <span class="keyword">private</span>:
<a name="l00120"></a>00120 <span class="keywordtype">void</span> ConstructL(); <span class="comment">// second construction phase</span>
<a name="l00121"></a>00121 <span class="comment">// functions for TCallBack protocol</span>
<a name="l00122"></a>00122 <span class="keyword">static</span> TInt Tick(TAny* aObject); <span class="comment">// directly called</span>
<a name="l00123"></a>00123 <span class="keywordtype">void</span> DoTick(); <span class="comment">// indirectly called</span>
<a name="l00124"></a>00124 <span class="keyword">private</span>:
<a name="l00125"></a>00125 <span class="comment">// constructor parameters</span>
<a name="l00126"></a>00126 TAppRunner& iAppRunner; <span class="comment">// notify when started and finished</span>
<a name="l00127"></a>00127 TInt iTotalTicks; <span class="comment">// total number of ticks requested</span>
<a name="l00128"></a>00128 TInt iTickInterval; <span class="comment">// the tick interval in microseconds</span>
<a name="l00129"></a>00129
<a name="l00130"></a>00130 <span class="comment">// things set up by ConstructL()</span>
<a name="l00131"></a>00131 TTime iStartTime; <span class="comment">// when we were started</span>
<a name="l00132"></a>00132 CPeriodic* iPeriodic; <span class="comment">// periodic timer active object</span>
<a name="l00133"></a>00133
<a name="l00134"></a>00134 <span class="comment">// remaining ticks will be decremented as we go</span>
<a name="l00135"></a>00135 TInt iTicksLeft; <span class="comment">// number of ticks before we expire</span>
<a name="l00136"></a>00136 TInt iTimerNumber; <span class="comment">// indentifying number for the timer</span>
<a name="l00137"></a>00137
<a name="l00138"></a>00138 <span class="comment">// seed for random delay generator</span>
<a name="l00139"></a>00139 TInt64 iDelaySeed;
<a name="l00140"></a>00140 };
<a name="l00141"></a>00141
<a name="l00142"></a>00142 <span class="comment">// protected C++ constructor</span>
<a name="l00143"></a>00143 CPeriodicRunner::CPeriodicRunner(TInt aTickInterval, TInt aTotalTicks, TAppRunner& aAppRunner)
<a name="l00144"></a>00144 : iAppRunner(aAppRunner), iTotalTicks(aTotalTicks), iTickInterval(aTickInterval)
<a name="l00145"></a>00145 {}
<a name="l00146"></a>00146
<a name="l00147"></a>00147 <span class="comment">// private second-phase constructor</span>
<a name="l00148"></a>00148 <span class="keywordtype">void</span> CPeriodicRunner::ConstructL()
<a name="l00149"></a>00149 {
<a name="l00150"></a>00150 iStartTime.HomeTime();
<a name="l00151"></a>00151 iPeriodic =CPeriodic::NewL(0); <span class="comment">// neutral priority</span>
<a name="l00152"></a>00152 iAppRunner.NotifyStarted();
<a name="l00153"></a>00153 iTimerNumber = iAppRunner.iActiveObjects; <span class="comment">// set idenfifying number for timer</span>
<a name="l00154"></a>00154 iTicksLeft = iTotalTicks;
<a name="l00155"></a>00155 <span class="comment">// variable (actually 1 second) delay and interval </span>
<a name="l00156"></a>00156 iPeriodic->Start(iTickInterval,iTickInterval,TCallBack(Tick, <span class="keyword">this</span>));
<a name="l00157"></a>00157 }
<a name="l00158"></a>00158
<a name="l00159"></a>00159 <span class="comment">// construct, add CPeriodic to active scheduler, and start it</span>
<a name="l00160"></a>00160 CPeriodicRunner* CPeriodicRunner::NewL(TInt aTickInterval, TInt aTotalTicks, TAppRunner& aAppRunner)
<a name="l00161"></a>00161 {
<a name="l00162"></a>00162 CPeriodicRunner* <span class="keyword">self</span>=<span class="keyword">new</span> (ELeave) CPeriodicRunner(aTickInterval, aTotalTicks, aAppRunner);
<a name="l00163"></a>00163 CleanupStack::PushL(<span class="keyword">self</span>);
<a name="l00164"></a>00164 <span class="keyword">self</span>->ConstructL();
<a name="l00165"></a>00165 CleanupStack::Pop();
<a name="l00166"></a>00166 <span class="keywordflow">return</span> <span class="keyword">self</span>;
<a name="l00167"></a>00167 }
<a name="l00168"></a>00168
<a name="l00169"></a>00169 <span class="comment">// destruct and give statistics</span>
<a name="l00170"></a>00170 CPeriodicRunner::~CPeriodicRunner()
<a name="l00171"></a>00171 {
<a name="l00172"></a>00172 TTimeIntervalMicroSeconds elapsedTime;
<a name="l00173"></a>00173 TTime currentTime;
<a name="l00174"></a>00174 <span class="comment">// set current time</span>
<a name="l00175"></a>00175 currentTime.HomeTime(); <span class="comment">// set currentTime to now</span>
<a name="l00176"></a>00176 <span class="comment">// find and show elapsed time & ticks </span>
<a name="l00177"></a>00177 elapsedTime = currentTime.MicroSecondsFrom(iStartTime);
<a name="l00178"></a>00178
<a name="l00179"></a>00179 _LIT(KFormat1,<span class="stringliteral">"Periodic timer %d finished after: %Ld microseconds for %d %dus ticks\n"</span>);
<a name="l00180"></a>00180 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KFormat1,iTimerNumber,elapsedTime.Int64(),iTotalTicks,iTickInterval);
<a name="l00181"></a>00181
<a name="l00182"></a>00182
<a name="l00183"></a>00183
<a name="l00184"></a>00184 <span class="comment">// cancel any outstanding request; delete owned CPeriodic object </span>
<a name="l00185"></a>00185 iPeriodic->Cancel();
<a name="l00186"></a>00186 <span class="keyword">delete</span> iPeriodic;
<a name="l00187"></a>00187 <span class="comment">// tell app runner we've finished (if we're last, scheduler will stop)</span>
<a name="l00188"></a>00188 iAppRunner.NotifyFinished();
<a name="l00189"></a>00189 }
<a name="l00190"></a>00190
<a name="l00191"></a>00191 <span class="comment">// private</span>
<a name="l00192"></a>00192 TInt CPeriodicRunner::Tick(TAny* aObject)
<a name="l00193"></a>00193 {
<a name="l00194"></a>00194 ((CPeriodicRunner*)aObject)->DoTick(); <span class="comment">// cast, and call non-static function</span>
<a name="l00195"></a>00195 <span class="keywordflow">return</span> 1;
<a name="l00196"></a>00196 }
<a name="l00197"></a>00197
<a name="l00198"></a>00198 <span class="comment">// private</span>
<a name="l00199"></a>00199 <span class="keywordtype">void</span> CPeriodicRunner::DoTick()
<a name="l00200"></a>00200 {
<a name="l00201"></a>00201 iTicksLeft--;
<a name="l00202"></a>00202 _LIT(KFormat2,<span class="stringliteral">"Periodic timer %d: %d ticks done\n"</span>);
<a name="l00203"></a>00203 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KFormat2, iTimerNumber, iTotalTicks - iTicksLeft);
<a name="l00204"></a>00204 <span class="keywordflow">if</span>(iTicksLeft==0)
<a name="l00205"></a>00205 {
<a name="l00206"></a>00206 <span class="keyword">delete</span> <span class="keyword">this</span>;
<a name="l00207"></a>00207 }
<a name="l00208"></a>00208 RandomDelay(iDelaySeed,iTimerNumber); <span class="comment">// a random delay to mess up the timing</span>
<a name="l00209"></a>00209 }
<a name="l00210"></a>00210
<a name="l00211"></a>00211 <span class="comment">/*</span>
<a name="l00212"></a>00212 <span class="comment"> CHeartbeatRunner class</span>
<a name="l00213"></a>00213 <span class="comment"></span>
<a name="l00214"></a>00214 <span class="comment"> This class receives beats in sync with the system clock. It also has a much</span>
<a name="l00215"></a>00215 <span class="comment"> nicer interface than for periodic timers - the MBeating mixin, which is nicely</span>
<a name="l00216"></a>00216 <span class="comment"> object-oriented.</span>
<a name="l00217"></a>00217 <span class="comment"></span>
<a name="l00218"></a>00218 <span class="comment"> Most of the time, the Beat() function is called which trivially updates the tick</span>
<a name="l00219"></a>00219 <span class="comment"> count. Occasionally, synchronization is lost, and the Synchronize() function</span>
<a name="l00220"></a>00220 <span class="comment"> is called instead: this must find out from the system time how many ticks should</span>
<a name="l00221"></a>00221 <span class="comment"> have been counted, and update things accordingly.</span>
<a name="l00222"></a>00222 <span class="comment"></span>
<a name="l00223"></a>00223 <span class="comment"> The destructor gives the same comparisons as the CPeriodic's. The discrepancy</span>
<a name="l00224"></a>00224 <span class="comment"> between the number of ticks and the number of seconds since construction should</span>
<a name="l00225"></a>00225 <span class="comment"> never be more than is accounted for by the last heartbeat.</span>
<a name="l00226"></a>00226 <span class="comment">*/</span>
<a name="l00227"></a>00227
<a name="l00228"></a>00228 <span class="keyword">class </span>CHeartbeatRunner : <span class="keyword">public</span> CBase, <span class="keyword">public</span> MBeating
<a name="l00229"></a>00229 {
<a name="l00230"></a>00230 <span class="keyword">public</span>:
<a name="l00231"></a>00231 <span class="comment">// construct, add CHeartbeat to active scheduler, and start it</span>
<a name="l00232"></a>00232 <span class="keyword">static</span> CHeartbeatRunner* NewL(TInt aTickInterval, TInt aTotalTicks, TAppRunner& aAppRunner);
<a name="l00233"></a>00233 ~CHeartbeatRunner(); <span class="comment">// destruct and give statistics</span>
<a name="l00234"></a>00234 <span class="keyword">protected</span>:
<a name="l00235"></a>00235 CHeartbeatRunner(TInt aTickInterval, TInt aTotalTicks, TAppRunner& aAppRunner);
<a name="l00236"></a>00236 <span class="keyword">private</span>:
<a name="l00237"></a>00237 <span class="keywordtype">void</span> ConstructL();
<a name="l00238"></a>00238 <span class="comment">// functions for MBeating protocol</span>
<a name="l00239"></a>00239 <span class="keywordtype">void</span> Beat(); <span class="comment">// called when beat works ok</span>
<a name="l00240"></a>00240 <span class="keywordtype">void</span> Synchronize(); <span class="comment">// called when we need to synchronize</span>
<a name="l00241"></a>00241 <span class="keyword">private</span>:
<a name="l00242"></a>00242 <span class="comment">// constructor parameters</span>
<a name="l00243"></a>00243 TAppRunner& iAppRunner; <span class="comment">// notify when started and finished</span>
<a name="l00244"></a>00244 TInt iTotalTicks; <span class="comment">// number of ticks requested</span>
<a name="l00245"></a>00245 TInt iTickInterval; <span class="comment">// tick length in microseconds</span>
<a name="l00246"></a>00246 <span class="comment">// things set up by ConstructL</span>
<a name="l00247"></a>00247 TTime iStartTime; <span class="comment">// when we were started</span>
<a name="l00248"></a>00248 CHeartbeat* iHeartbeat; <span class="comment">// heartbeat active object</span>
<a name="l00249"></a>00249 <span class="comment">// ticks left decrements as we go</span>
<a name="l00250"></a>00250 TInt iTicksLeft; <span class="comment">// number of ticks before we expire</span>
<a name="l00251"></a>00251 TInt iTimerNumber; <span class="comment">// indentifying number for the timer</span>
<a name="l00252"></a>00252 <span class="comment">// seed for random delay generator</span>
<a name="l00253"></a>00253 TInt64 iDelaySeed;
<a name="l00254"></a>00254 };
<a name="l00255"></a>00255
<a name="l00256"></a>00256 <span class="comment">// protected C++ constructor</span>
<a name="l00257"></a>00257 CHeartbeatRunner::CHeartbeatRunner(TInt aTickInterval, TInt aTotalTicks, TAppRunner& aAppRunner)
<a name="l00258"></a>00258 :iAppRunner(aAppRunner), iTotalTicks(aTotalTicks), iTickInterval(aTickInterval)
<a name="l00259"></a>00259 {}
<a name="l00260"></a>00260
<a name="l00261"></a>00261 <span class="comment">// private second-phase constructor</span>
<a name="l00262"></a>00262 <span class="keywordtype">void</span> CHeartbeatRunner::ConstructL()
<a name="l00263"></a>00263 {
<a name="l00264"></a>00264 iStartTime.HomeTime();
<a name="l00265"></a>00265 iHeartbeat=CHeartbeat::NewL(0); <span class="comment">// neutral priority</span>
<a name="l00266"></a>00266 iAppRunner.NotifyStarted();
<a name="l00267"></a>00267 iTimerNumber = iAppRunner.iActiveObjects; <span class="comment">// set idenfifying number for timer</span>
<a name="l00268"></a>00268 iTicksLeft = iTotalTicks;
<a name="l00269"></a>00269 <span class="comment">// start the heartbeat timer, beating exactly on the second</span>
<a name="l00270"></a>00270 iHeartbeat->Start(ETwelveOClock,<span class="keyword">this</span>);
<a name="l00271"></a>00271 }
<a name="l00272"></a>00272
<a name="l00273"></a>00273 <span class="comment">// construct, add CHeartbeat to active scheduler, and start it</span>
<a name="l00274"></a>00274 CHeartbeatRunner* CHeartbeatRunner::NewL(TInt aTickInterval, TInt aTotalTicks, TAppRunner& aAppRunner)
<a name="l00275"></a>00275 {
<a name="l00276"></a>00276 CHeartbeatRunner* <span class="keyword">self</span>=<span class="keyword">new</span> (ELeave) CHeartbeatRunner(aTickInterval, aTotalTicks, aAppRunner);
<a name="l00277"></a>00277 CleanupStack::PushL(<span class="keyword">self</span>);
<a name="l00278"></a>00278 <span class="keyword">self</span>->ConstructL();
<a name="l00279"></a>00279 CleanupStack::Pop();
<a name="l00280"></a>00280 <span class="keywordflow">return</span> <span class="keyword">self</span>;
<a name="l00281"></a>00281 }
<a name="l00282"></a>00282
<a name="l00283"></a>00283 <span class="comment">// destruct and give statistics</span>
<a name="l00284"></a>00284 CHeartbeatRunner::~CHeartbeatRunner()
<a name="l00285"></a>00285 {
<a name="l00286"></a>00286 TTimeIntervalMicroSeconds elapsedTime;
<a name="l00287"></a>00287 TTime currentTime;
<a name="l00288"></a>00288 currentTime.HomeTime(); <span class="comment">// set current time to now</span>
<a name="l00289"></a>00289 <span class="comment">// find and show elapsed time & ticks </span>
<a name="l00290"></a>00290 elapsedTime = currentTime.MicroSecondsFrom(iStartTime);
<a name="l00291"></a>00291
<a name="l00292"></a>00292 _LIT(KFormat3,<span class="stringliteral">"Heartbeat timer %d finished after: %Ld microseonds for %d %dus ticks\n"</span>);
<a name="l00293"></a>00293 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KFormat3,iTimerNumber,elapsedTime.Int64(),iTotalTicks,iTickInterval);
<a name="l00294"></a>00294
<a name="l00295"></a>00295 <span class="comment">// cancel any outstanding request; delete owned CPeriodic object </span>
<a name="l00296"></a>00296 iHeartbeat->Cancel();
<a name="l00297"></a>00297 <span class="keyword">delete</span> iHeartbeat;
<a name="l00298"></a>00298 <span class="comment">// tell app runner we've finished (if last, scheduler will stop)</span>
<a name="l00299"></a>00299 iAppRunner.NotifyFinished();
<a name="l00300"></a>00300 }
<a name="l00301"></a>00301
<a name="l00302"></a>00302 <span class="comment">// private</span>
<a name="l00303"></a>00303 <span class="keywordtype">void</span> CHeartbeatRunner::Beat()
<a name="l00304"></a>00304 {
<a name="l00305"></a>00305 iTicksLeft--;
<a name="l00306"></a>00306 <span class="keywordflow">if</span>(iTicksLeft<=0)
<a name="l00307"></a>00307 <span class="keyword">delete</span> <span class="keyword">this</span>;
<a name="l00308"></a>00308 <span class="keywordflow">else</span>
<a name="l00309"></a>00309 RandomDelay(iDelaySeed,iTimerNumber); <span class="comment">// a random delay to mess up the timing</span>
<a name="l00310"></a>00310 }
<a name="l00311"></a>00311
<a name="l00312"></a>00312 <span class="comment">// private</span>
<a name="l00313"></a>00313 <span class="keywordtype">void</span> CHeartbeatRunner::Synchronize()
<a name="l00314"></a>00314 {
<a name="l00315"></a>00315 TInt ticksMissed = 0;
<a name="l00316"></a>00316 <span class="comment">// what time in microseconds should be for this tick</span>
<a name="l00317"></a>00317 TTime desiredTime = iStartTime + TTimeIntervalMicroSeconds((iTotalTicks - iTicksLeft) * iTickInterval);
<a name="l00318"></a>00318 TTime currentTime; <span class="comment">// set current time to now</span>
<a name="l00319"></a>00319 currentTime.HomeTime();
<a name="l00320"></a>00320 TTimeIntervalMicroSeconds missedTime = currentTime.MicroSecondsFrom(desiredTime);
<a name="l00321"></a>00321 <span class="comment">// Calculate the ticks missed (quickly!)</span>
<a name="l00322"></a>00322 TInt64 missedTimeInt = missedTime.Int64(); <span class="comment">// convert the missed time interval to an Int64</span>
<a name="l00323"></a>00323
<a name="l00324"></a>00324 ticksMissed = (missedTimeInt / iTickInterval);
<a name="l00325"></a>00325 <span class="comment">//ticksMissed = (missedTimeInt / iTickInterval).GetTInt();</span>
<a name="l00326"></a>00326
<a name="l00327"></a>00327
<a name="l00328"></a>00328 <span class="comment">// The following loop increments the ticks missed by the same amount, but takes much longer</span>
<a name="l00329"></a>00329 <span class="comment">// while (desiredTime < currentTime)</span>
<a name="l00330"></a>00330 <span class="comment">// {</span>
<a name="l00331"></a>00331 <span class="comment">// desiredTime = desiredTime - TTimeIntervalMicroSeconds(iTickInterval);</span>
<a name="l00332"></a>00332 <span class="comment">// ticksMissed++;</span>
<a name="l00333"></a>00333 <span class="comment">// }</span>
<a name="l00334"></a>00334 _LIT(KFormat4,<span class="stringliteral">"Ticks done %d\n"</span>);
<a name="l00335"></a>00335 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KFormat4, (iTotalTicks -iTicksLeft));
<a name="l00336"></a>00336
<a name="l00337"></a>00337 iTicksLeft = iTicksLeft - ticksMissed;
<a name="l00338"></a>00338 TTimeIntervalMicroSeconds elapsedTime;
<a name="l00339"></a>00339 elapsedTime = currentTime.MicroSecondsFrom(iStartTime); <span class="comment">// find and show elapsed time & ticks </span>
<a name="l00340"></a>00340 _LIT(KFormat5,<span class="stringliteral">"Elapsed time: %Ld microseconds\n"</span>);
<a name="l00341"></a>00341 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KFormat5, elapsedTime.Int64());
<a name="l00342"></a>00342
<a name="l00343"></a>00343 _LIT(KFormat6,<span class="stringliteral">"Synchronize heartbeat timer %d: ticks missed %d: left %d: done now %d\n"</span>);
<a name="l00344"></a>00344 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KFormat6,
<a name="l00345"></a>00345 iTimerNumber,
<a name="l00346"></a>00346 ticksMissed,
<a name="l00347"></a>00347 iTicksLeft,
<a name="l00348"></a>00348 ((iTotalTicks - iTicksLeft) <= iTotalTicks) ? iTotalTicks - iTicksLeft : iTotalTicks
<a name="l00349"></a>00349 );
<a name="l00350"></a>00350 <span class="comment">// iTicksLeft can be less than zero</span>
<a name="l00351"></a>00351 <span class="keywordflow">if</span>(iTicksLeft<=0)
<a name="l00352"></a>00352 {
<a name="l00353"></a>00353 <span class="keyword">delete</span> <span class="keyword">this</span>;
<a name="l00354"></a>00354 }
<a name="l00355"></a>00355 }
<a name="l00356"></a>00356
<a name="l00357"></a>00357 <span class="comment">/*</span>
<a name="l00358"></a>00358 <span class="comment"> TAppRunner class</span>
<a name="l00359"></a>00359 <span class="comment"></span>
<a name="l00360"></a>00360 <span class="comment"> Encapsulates logic for stopping the active scheduler</span>
<a name="l00361"></a>00361 <span class="comment">*/</span>
<a name="l00362"></a>00362
<a name="l00363"></a>00363
<a name="l00364"></a>00364 <span class="comment">// do the example</span>
<a name="l00365"></a>00365
<a name="l00366"></a>00366 <span class="keywordtype">void</span> doExampleL()
<a name="l00367"></a>00367 {
<a name="l00368"></a>00368 <span class="comment">// Make and install the active scheduler</span>
<a name="l00369"></a>00369 CActiveScheduler* scheduler = <span class="keyword">new</span> (ELeave) CActiveScheduler;
<a name="l00370"></a>00370
<a name="l00371"></a>00371 <span class="comment">// Push onto clean-up stack</span>
<a name="l00372"></a>00372 CleanupStack::PushL(scheduler);
<a name="l00373"></a>00373
<a name="l00374"></a>00374 <span class="comment">// Install as active scheduler</span>
<a name="l00375"></a>00375 CActiveScheduler::Install(scheduler);
<a name="l00376"></a>00376
<a name="l00377"></a>00377 <span class="comment">// Controls the stopping of the scheduler</span>
<a name="l00378"></a>00378 TAppRunner appRunner;
<a name="l00379"></a>00379
<a name="l00380"></a>00380 <span class="comment">// Set the tick interval to 1 second.</span>
<a name="l00381"></a>00381 TInt TickInterval = 1000000;
<a name="l00382"></a>00382
<a name="l00383"></a>00383 <span class="comment">// run each kind of timer for increasing numbers of ticks</span>
<a name="l00384"></a>00384 <span class="comment">// was 10/40/10</span>
<a name="l00385"></a>00385
<a name="l00386"></a>00386 <span class="keywordflow">for</span> (TInt total_ticks=4; total_ticks<=6; total_ticks+=2)
<a name="l00387"></a>00387 {
<a name="l00388"></a>00388 <span class="comment">// Create periodic timer</span>
<a name="l00389"></a>00389 <span class="comment">//</span>
<a name="l00390"></a>00390 <span class="comment">// [nb Comment next line out if you just want to see heart beat runner]</span>
<a name="l00391"></a>00391 CPeriodicRunner::NewL(TickInterval, total_ticks, appRunner);
<a name="l00392"></a>00392
<a name="l00393"></a>00393 <span class="comment">// Create hearbeat</span>
<a name="l00394"></a>00394 <span class="comment">//</span>
<a name="l00395"></a>00395 <span class="comment">// [nb Comment next line out if you just want to see periodic timer]</span>
<a name="l00396"></a>00396 CHeartbeatRunner::NewL(TickInterval, total_ticks, appRunner);
<a name="l00397"></a>00397 }
<a name="l00398"></a>00398
<a name="l00399"></a>00399 CActiveScheduler::Start();
<a name="l00400"></a>00400 CleanupStack::PopAndDestroy(); <span class="comment">// scheduler</span>
<a name="l00401"></a>00401 }
<a name="l00402"></a>00402
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