Symbian3/Examples/guid-6013a680-57f9-415b-8851-c4fa63356636/subtractor_8cpp_source.html
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<h1>examples/Base/IPC/condvar/condvarglobal/src/subtractor.cpp</h1><a href="subtractor_8cpp.html">Go to the documentation of this file.</a><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">// Copyright (c) 2008-2009 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">// Implements the write operation on a shared memory block.</span>
<a name="l00015"></a>00015 <span class="comment">//</span>
<a name="l00016"></a>00016
<a name="l00017"></a>00017
<a name="l00018"></a>00018
<a name="l00022"></a>00022 <span class="preprocessor">#include "<a class="code" href="sharedmem_8h.html">sharedmem.h</a>"</span>
<a name="l00023"></a>00023 <span class="preprocessor">#include "<a class="code" href="subtractor_8h.html">subtractor.h</a>"</span>
<a name="l00024"></a>00024
<a name="l00030"></a><a class="code" href="class_c_subtractor.html#a7d6002b0b8610a3241853c7fb4ef3995">00030</a> <a class="code" href="class_c_subtractor.html">CSubtractor</a>* <a class="code" href="class_c_subtractor.html#a7d6002b0b8610a3241853c7fb4ef3995">CSubtractor::NewL</a>(CConsoleBase* aConsole)
<a name="l00031"></a>00031 {
<a name="l00032"></a>00032 <a class="code" href="class_c_subtractor.html">CSubtractor</a>* <span class="keyword">self</span> = <span class="keyword">new</span> (ELeave) <a class="code" href="class_c_subtractor.html">CSubtractor</a>;
<a name="l00033"></a>00033 CleanupStack::PushL(<span class="keyword">self</span>);
<a name="l00034"></a>00034 <span class="keyword">self</span>->ConstructL(aConsole);
<a name="l00035"></a>00035 CleanupStack::Pop(<span class="keyword">self</span>);
<a name="l00036"></a>00036 <span class="keywordflow">return</span> <span class="keyword">self</span>;
<a name="l00037"></a>00037 }
<a name="l00038"></a>00038
<a name="l00043"></a><a class="code" href="class_c_subtractor.html#adafc90c62c12777fc2c1670cfc65ff7e">00043</a> <span class="keywordtype">void</span> <a class="code" href="class_c_subtractor.html#adafc90c62c12777fc2c1670cfc65ff7e">CSubtractor::RunL</a>()
<a name="l00044"></a>00044 {
<a name="l00045"></a>00045 <span class="comment">// Get the key code.</span>
<a name="l00046"></a>00046 TUint8 option = iConsole->KeyCode();
<a name="l00047"></a>00047 <span class="comment">// Print the selected option.</span>
<a name="l00048"></a>00048 <a class="code" href="secureclientandserver_8h.html#a5eadd4429627d82193b37536d4faa03a">_LIT</a>(KTextFormat,<span class="stringliteral">"%c\n"</span>);
<a name="l00049"></a>00049 iConsole->Printf(KTextFormat,option);
<a name="l00050"></a>00050 <span class="comment">// Stop the timer and the active scheduler.</span>
<a name="l00051"></a>00051 <a class="code" href="class_c_subtractor.html#a6fccf6a6e4f1b731f1d2105ccac84484">StopTimer</a>();
<a name="l00052"></a>00052 CActiveScheduler::Stop();
<a name="l00053"></a>00053 }
<a name="l00054"></a>00054
<a name="l00058"></a><a class="code" href="class_c_subtractor.html#a8fe681f7232eb2d9a8e5d6b00d56d461">00058</a> <span class="keywordtype">void</span> <a class="code" href="class_c_subtractor.html#a8fe681f7232eb2d9a8e5d6b00d56d461">CSubtractor::DoCancel</a>()
<a name="l00059"></a>00059 {
<a name="l00060"></a>00060 <span class="keywordflow">if</span>(IsActive())
<a name="l00061"></a>00061 {
<a name="l00062"></a>00062 <span class="comment">// Cancel any outstanding read requests.</span>
<a name="l00063"></a>00063 iConsole->ReadCancel();
<a name="l00064"></a>00064 }
<a name="l00065"></a>00065 }
<a name="l00066"></a>00066
<a name="l00070"></a><a class="code" href="class_c_subtractor.html#a6641d546e8cf49ad7295cf4045d6c901">00070</a> <a class="code" href="class_c_subtractor.html#a6641d546e8cf49ad7295cf4045d6c901">CSubtractor::~CSubtractor</a>()
<a name="l00071"></a>00071 {
<a name="l00072"></a>00072 <span class="comment">// Cancel all outstanding requests.</span>
<a name="l00073"></a>00073 <a class="code" href="class_c_subtractor.html#a8fe681f7232eb2d9a8e5d6b00d56d461">DoCancel</a>();
<a name="l00074"></a>00074 <span class="comment">// Delete the timer object.</span>
<a name="l00075"></a>00075 iPeriodic->Cancel();
<a name="l00076"></a>00076 <span class="keyword">delete</span> iPeriodic;
<a name="l00077"></a>00077 }
<a name="l00078"></a>00078
<a name="l00082"></a>00082 CSubtractor::CSubtractor():CActive(EPriorityUserInput)
<a name="l00083"></a>00083 {
<a name="l00084"></a>00084 }
<a name="l00085"></a>00085
<a name="l00091"></a>00091 <span class="keywordtype">void</span> CSubtractor::ConstructL(CConsoleBase* aConsole)
<a name="l00092"></a>00092 {
<a name="l00093"></a>00093 <span class="comment">// Open the global condition variable.</span>
<a name="l00094"></a>00094 User::LeaveIfError(iCondVar.OpenGlobal(KCondVarName));
<a name="l00095"></a>00095 <span class="comment">// Open the global chunk variable.</span>
<a name="l00096"></a>00096 User::LeaveIfError(iChunk.OpenGlobal(KChunkName,EFalse));
<a name="l00097"></a>00097 <span class="comment">// Open the global mutex variable.</span>
<a name="l00098"></a>00098 User::LeaveIfError(iMutex.OpenGlobal(KMutexName));
<a name="l00099"></a>00099
<a name="l00100"></a>00100 <span class="comment">// Create the CPeriodic object.</span>
<a name="l00101"></a>00101 iPeriodic = <a class="code" href="class_c_subtractor.html#a7d6002b0b8610a3241853c7fb4ef3995">CPeriodic::NewL</a>(CActive::EPriorityUserInput);
<a name="l00102"></a>00102 iConsole = aConsole;
<a name="l00103"></a>00103
<a name="l00104"></a>00104 <span class="comment">// Add the object to the active scheduler.</span>
<a name="l00105"></a>00105 CActiveScheduler::Add(<span class="keyword">this</span>);
<a name="l00106"></a>00106 }
<a name="l00107"></a>00107
<a name="l00111"></a><a class="code" href="class_c_subtractor.html#a0d39bfb8170e1923541fa6efd915d206">00111</a> <span class="keywordtype">void</span> <a class="code" href="class_c_subtractor.html#a0d39bfb8170e1923541fa6efd915d206">CSubtractor::ReadFunction</a>()
<a name="l00112"></a>00112 {
<a name="l00113"></a>00113 <a class="code" href="secureclientandserver_8h.html#a5eadd4429627d82193b37536d4faa03a">_LIT</a>(KTextMessage,<span class="stringliteral">"Press a key to exit...\n"</span>);
<a name="l00114"></a>00114 iConsole->Printf(KTextMessage);
<a name="l00115"></a>00115 <span class="comment">// Wait for a key press event.</span>
<a name="l00116"></a>00116 iConsole->Read(iStatus);
<a name="l00117"></a>00117 SetActive();
<a name="l00118"></a>00118 }
<a name="l00119"></a>00119
<a name="l00124"></a><a class="code" href="class_c_subtractor.html#ab5a9d2c973fb9387a6519971ddcb61c2">00124</a> <span class="keywordtype">void</span> <a class="code" href="class_c_subtractor.html#ab5a9d2c973fb9387a6519971ddcb61c2">CSubtractor::StartTimer</a>()
<a name="l00125"></a>00125 {
<a name="l00126"></a>00126 iPeriodic->Start(0,3000000,TCallBack(<a class="code" href="class_c_subtractor.html#a44265608e41e7a13f8790fcd68a5589d">SubtractFunction</a>,<span class="keyword">this</span>));
<a name="l00127"></a>00127 }
<a name="l00128"></a>00128
<a name="l00132"></a><a class="code" href="class_c_subtractor.html#a6fccf6a6e4f1b731f1d2105ccac84484">00132</a> <span class="keywordtype">void</span> <a class="code" href="class_c_subtractor.html#a6fccf6a6e4f1b731f1d2105ccac84484">CSubtractor::StopTimer</a>()
<a name="l00133"></a>00133 {
<a name="l00134"></a>00134 <span class="comment">// Cancel the outstanding request.</span>
<a name="l00135"></a>00135 iPeriodic->Cancel();
<a name="l00136"></a>00136 }
<a name="l00137"></a>00137
<a name="l00143"></a><a class="code" href="class_c_subtractor.html#a44265608e41e7a13f8790fcd68a5589d">00143</a> TInt <a class="code" href="class_c_subtractor.html#a44265608e41e7a13f8790fcd68a5589d">CSubtractor::SubtractFunction</a>(TAny* aPtr)
<a name="l00144"></a>00144 {
<a name="l00145"></a>00145 <a class="code" href="class_c_subtractor.html">CSubtractor</a>* ptr = <span class="keyword">static_cast<</span><a class="code" href="class_c_subtractor.html">CSubtractor</a>*<span class="keyword">></span> (aPtr);
<a name="l00146"></a>00146 <a class="code" href="secureclientandserver_8h.html#a5eadd4429627d82193b37536d4faa03a">_LIT</a>(KTxtPanic,<span class="stringliteral">"Unexpected datatype\n"</span>);
<a name="l00147"></a>00147 __ASSERT_ALWAYS(ptr,User::Panic(KTxtPanic,-1));
<a name="l00148"></a>00148 <span class="comment">// Invoke the Subtract() function.</span>
<a name="l00149"></a>00149 ptr-><a class="code" href="class_c_subtractor.html#aaea4ddea47a64945f5dcd280d9f5adcb">Subtract</a>();
<a name="l00150"></a>00150 <span class="keywordflow">return</span> KErrNone;
<a name="l00151"></a>00151 }
<a name="l00152"></a>00152
<a name="l00156"></a><a class="code" href="class_c_subtractor.html#aaea4ddea47a64945f5dcd280d9f5adcb">00156</a> <span class="keywordtype">void</span> <a class="code" href="class_c_subtractor.html#aaea4ddea47a64945f5dcd280d9f5adcb">CSubtractor::Subtract</a>()
<a name="l00157"></a>00157 {
<a name="l00158"></a>00158 <span class="comment">// Acquire the mutex.</span>
<a name="l00159"></a>00159 iMutex.Wait();
<a name="l00160"></a>00160
<a name="l00161"></a>00161 <span class="comment">// Get a random number.</span>
<a name="l00162"></a>00162 TInt randVal = Math::Random() % 10;
<a name="l00163"></a>00163
<a name="l00164"></a>00164 <span class="comment">// Get the address of the chunk.</span>
<a name="l00165"></a>00165 TUint8 *ptr = iChunk.Base();
<a name="l00166"></a>00166
<a name="l00167"></a>00167 <span class="comment">// Print the value of the chunk before subtraction.</span>
<a name="l00168"></a>00168 iConsole->Printf(_L(<span class="stringliteral">"Value read from the shared memory: %d\n"</span>),*ptr);
<a name="l00169"></a>00169
<a name="l00170"></a>00170 <span class="comment">// Subtract the random value from the shared memory variable.</span>
<a name="l00171"></a>00171 *ptr -= randVal;
<a name="l00172"></a>00172
<a name="l00173"></a>00173 <span class="keywordflow">while</span>(*ptr < <a class="code" href="sharedmem_8h.html#a817ce7a9d8ca9ead92509953f8dcdcad">KLowerThreshold</a>)
<a name="l00174"></a>00174 {
<a name="l00175"></a>00175 <span class="comment">// Wait on the condition variable if the result is lesser than 0.</span>
<a name="l00176"></a>00176 <a class="code" href="secureclientandserver_8h.html#a5eadd4429627d82193b37536d4faa03a">_LIT</a>(KBlockMessage,<span class="stringliteral">"Subtractor blocked by condVar until Adder signals that value has been increased.\nIntermediate value of the chunk = %d\n"</span>);
<a name="l00177"></a>00177 iConsole->Printf(KBlockMessage,*ptr);
<a name="l00178"></a>00178 iCondVar.Wait(iMutex);
<a name="l00179"></a>00179 }
<a name="l00180"></a>00180 <span class="comment">// Print the updated value of the chunk.</span>
<a name="l00181"></a>00181 iConsole->Printf(_L(<span class="stringliteral">"Value of the shared memory decreased to : %d\n"</span>),*ptr);
<a name="l00182"></a>00182
<a name="l00183"></a>00183 <span class="comment">// Signal the mutex and the condition variable.</span>
<a name="l00184"></a>00184 <span class="keywordflow">if</span>(*ptr < <a class="code" href="sharedmem_8h.html#a0f2ae9d486d80c446844be5480b7bbc2">KUpperThreshold</a>)
<a name="l00185"></a>00185 {
<a name="l00186"></a>00186 <span class="comment">// Signal that the level is safe for addition to (re)start.</span>
<a name="l00187"></a>00187 iCondVar.Signal();
<a name="l00188"></a>00188 }
<a name="l00189"></a>00189 iMutex.Signal();
<a name="l00190"></a>00190 }
<a name="l00191"></a>00191
<a name="l00192"></a>00192 LOCAL_D CConsoleBase* console;
<a name="l00193"></a>00193 LOCAL_C <span class="keywordtype">void</span> DoExampleL();
<a name="l00194"></a>00194 LOCAL_C <span class="keywordtype">void</span> callExampleL();
<a name="l00195"></a>00195
<a name="l00196"></a>00196 LOCAL_C <span class="keywordtype">void</span> DoExampleL()
<a name="l00197"></a>00197 {
<a name="l00198"></a>00198 <span class="comment">// Create and install the active scheduler.</span>
<a name="l00199"></a>00199 CActiveScheduler* scheduler = <span class="keyword">new</span> (ELeave) CActiveScheduler();
<a name="l00200"></a>00200 CleanupStack::PushL(scheduler);
<a name="l00201"></a>00201 CActiveScheduler::Install(scheduler);
<a name="l00202"></a>00202
<a name="l00203"></a>00203 <span class="comment">// Create the CSubtractor object.</span>
<a name="l00204"></a>00204 <a class="code" href="class_c_subtractor.html">CSubtractor</a>* subtractor = <a class="code" href="class_c_subtractor.html#a7d6002b0b8610a3241853c7fb4ef3995">CSubtractor::NewL</a>(console);
<a name="l00205"></a>00205 CleanupStack::PushL(subtractor);
<a name="l00206"></a>00206
<a name="l00207"></a>00207 <span class="comment">// Start the timer of the CSubtractor object.</span>
<a name="l00208"></a>00208 subtractor-><a class="code" href="class_c_subtractor.html#ab5a9d2c973fb9387a6519971ddcb61c2">StartTimer</a>();
<a name="l00209"></a>00209 <span class="comment">// Issue an asynchronous read request.</span>
<a name="l00210"></a>00210 subtractor-><a class="code" href="class_c_subtractor.html#a0d39bfb8170e1923541fa6efd915d206">ReadFunction</a>();
<a name="l00211"></a>00211 <span class="comment">// Start the active scheduler.</span>
<a name="l00212"></a>00212 CActiveScheduler::Start();
<a name="l00213"></a>00213
<a name="l00214"></a>00214 CleanupStack::PopAndDestroy(2,scheduler);
<a name="l00215"></a>00215 }
<a name="l00216"></a>00216
<a name="l00217"></a><a class="code" href="subtractor_8cpp.html#a0f358e9c4355138f629b8c4f37310295">00217</a> GLDEF_C TInt E32Main() <span class="comment">// main function called by E32</span>
<a name="l00218"></a>00218 {
<a name="l00219"></a>00219 __UHEAP_MARK;
<a name="l00220"></a>00220 CTrapCleanup* cleanup=CTrapCleanup::New(); <span class="comment">// get clean-up stack</span>
<a name="l00221"></a>00221 TRAPD(error,callExampleL()); <span class="comment">// more initializations, then do example</span>
<a name="l00222"></a>00222 <span class="keyword">delete</span> cleanup; <span class="comment">// destroy clean-up stack</span>
<a name="l00223"></a>00223 __ASSERT_ALWAYS(!error,User::Panic(KTxtEPOC32EX,error));
<a name="l00224"></a>00224 __UHEAP_MARKEND;
<a name="l00225"></a>00225 <span class="keywordflow">return</span> 0; <span class="comment">// and return</span>
<a name="l00226"></a>00226 }
<a name="l00227"></a>00227
<a name="l00228"></a>00228 LOCAL_C <span class="keywordtype">void</span> callExampleL() <span class="comment">// initialise and call example code under cleanup stack</span>
<a name="l00229"></a>00229 {
<a name="l00230"></a>00230 console=Console::NewL(KTxtExampleCode,TSize(KConsFullScreen,KConsFullScreen));
<a name="l00231"></a>00231 CleanupStack::PushL(console);
<a name="l00232"></a>00232 TRAPD(error,DoExampleL()); <span class="comment">// perform example function</span>
<a name="l00233"></a>00233 <span class="keywordflow">if</span> (error)
<a name="l00234"></a>00234 console->Printf(KFormatFailed, error);
<a name="l00235"></a>00235 <span class="keywordflow">else</span>
<a name="l00236"></a>00236 console->Printf(KTxtOK);
<a name="l00237"></a>00237 console->Printf(KTxtPressAnyKey);
<a name="l00238"></a>00238 console->Getch(); <span class="comment">// get and ignore character</span>
<a name="l00239"></a>00239 CleanupStack::PopAndDestroy(); <span class="comment">// close console</span>
<a name="l00240"></a>00240 }
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