Symbian3/Examples/guid-6013a680-57f9-415b-8851-c4fa63356636/_lexer_8cpp_source.html
Week 32 contribution of PDK documentation content. See release notes for details. Fixes bug Bug 3582
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<h1>examples/Base/BufsAndStrings/Lexer/Lexer.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">//</span>
<a name="l00015"></a>00015
<a name="l00016"></a>00016 <span class="preprocessor">#include <e32std.h></span>
<a name="l00017"></a>00017 <span class="preprocessor">#include <e32cons.h></span>
<a name="l00018"></a>00018
<a name="l00019"></a>00019 <span class="keyword">const</span> TInt KMaxCalcCommandBuffer=80;
<a name="l00020"></a>00020
<a name="l00021"></a>00021 <span class="comment">//Common literal text</span>
<a name="l00022"></a>00022
<a name="l00023"></a>00023
<a name="l00024"></a>00024 <a class="code" href="secureclientandserver_8h.html#a5eadd4429627d82193b37536d4faa03a">_LIT</a>(KTxtErrInExpress,<span class="stringliteral">" Error in expression, cannot evaluate. "</span>);
<a name="l00025"></a>00025
<a name="l00026"></a>00026
<a name="l00027"></a>00027 CConsoleBase* console;
<a name="l00028"></a>00028
<a name="l00029"></a>00029
<a name="l00031"></a>00031 <span class="comment">// Stack classes</span>
<a name="l00033"></a>00033 <span class="comment"></span>
<a name="l00034"></a>00034 <span class="comment">//</span>
<a name="l00035"></a>00035 <span class="comment">// Stack element class - linked list of TReals</span>
<a name="l00036"></a>00036 <span class="comment">//</span>
<a name="l00037"></a>00037
<a name="l00038"></a>00038 <span class="keyword">class </span>CRpnStackElement : <span class="keyword">public</span> CBase
<a name="l00039"></a>00039 {
<a name="l00040"></a>00040 <span class="keyword">friend</span> <span class="keyword">class </span>CRpnStack ;
<a name="l00041"></a>00041
<a name="l00042"></a>00042 <span class="keyword">private</span>:
<a name="l00043"></a>00043 CRpnStackElement* iNext ;
<a name="l00044"></a>00044 TReal iValue ;
<a name="l00045"></a>00045
<a name="l00046"></a>00046 <span class="keyword">public</span>:
<a name="l00047"></a>00047 <span class="keyword">static</span> CRpnStackElement* NewL ( <span class="keyword">const</span> TReal& aReal, CRpnStackElement* aStackElement) ;
<a name="l00048"></a>00048 <span class="keywordtype">void</span> ConstructL (<span class="keyword">const</span> TReal& aReal, CRpnStackElement* aStackElement) ;
<a name="l00049"></a>00049
<a name="l00050"></a>00050 <span class="keyword">public</span>:
<a name="l00051"></a>00051 CRpnStackElement() {} ;
<a name="l00052"></a>00052 } ;
<a name="l00053"></a>00053
<a name="l00054"></a>00054
<a name="l00055"></a>00055 <span class="comment">//</span>
<a name="l00056"></a>00056 <span class="comment">// Stack class - just constructor, destructor, push, pop & empty-test.</span>
<a name="l00057"></a>00057 <span class="comment">//</span>
<a name="l00058"></a>00058
<a name="l00059"></a>00059 <span class="keyword">class </span>CRpnStack : <span class="keyword">public</span> CBase
<a name="l00060"></a>00060 {
<a name="l00061"></a>00061 <span class="keyword">private</span>:
<a name="l00062"></a>00062 CRpnStackElement* iTop ; <span class="comment">// pointer to top of stack element</span>
<a name="l00063"></a>00063
<a name="l00064"></a>00064 <span class="keyword">public</span>:
<a name="l00065"></a>00065 <span class="keyword">static</span> CRpnStack* NewL () ;
<a name="l00066"></a>00066 <span class="keywordtype">void</span> ConstructL () ;
<a name="l00067"></a>00067
<a name="l00068"></a>00068 ~CRpnStack() ;
<a name="l00069"></a>00069 TReal Pop () ;
<a name="l00070"></a>00070 <span class="keywordtype">void</span> Push (TReal aReal) ;
<a name="l00071"></a>00071 TBool IsEmpty () ;
<a name="l00072"></a>00072 } ;
<a name="l00073"></a>00073
<a name="l00074"></a>00074
<a name="l00076"></a>00076 <span class="comment">// Stack class implementations</span>
<a name="l00078"></a>00078 <span class="comment"></span>
<a name="l00079"></a>00079 <span class="comment">// stack element construction (2-part)</span>
<a name="l00080"></a>00080 CRpnStackElement* CRpnStackElement::NewL(<span class="keyword">const</span> TReal& aReal, CRpnStackElement* aStackElement)
<a name="l00081"></a>00081 {
<a name="l00082"></a>00082 CRpnStackElement* <span class="keyword">self</span> = <span class="keyword">new</span> (ELeave) CRpnStackElement ;
<a name="l00083"></a>00083 CleanupStack::PushL(<span class="keyword">self</span>);
<a name="l00084"></a>00084 <span class="keyword">self</span>->ConstructL(aReal, aStackElement);
<a name="l00085"></a>00085 CleanupStack::Pop();
<a name="l00086"></a>00086 <span class="keywordflow">return</span> <span class="keyword">self</span>;
<a name="l00087"></a>00087 }
<a name="l00088"></a>00088
<a name="l00089"></a>00089
<a name="l00090"></a>00090 <span class="keywordtype">void</span> CRpnStackElement::ConstructL(<span class="keyword">const</span> TReal& aReal, CRpnStackElement* aStackElement)
<a name="l00091"></a>00091 {
<a name="l00092"></a>00092 iValue = aReal;
<a name="l00093"></a>00093 iNext = aStackElement ;
<a name="l00094"></a>00094 }
<a name="l00095"></a>00095
<a name="l00096"></a>00096
<a name="l00097"></a>00097 <span class="comment">// stack construction</span>
<a name="l00098"></a>00098 CRpnStack* CRpnStack::NewL()
<a name="l00099"></a>00099 {
<a name="l00100"></a>00100 CRpnStack* <span class="keyword">self</span> = <span class="keyword">new</span> (ELeave) CRpnStack ;
<a name="l00101"></a>00101 CleanupStack::PushL(<span class="keyword">self</span>);
<a name="l00102"></a>00102 <span class="keyword">self</span>->ConstructL();
<a name="l00103"></a>00103 CleanupStack::Pop();
<a name="l00104"></a>00104 <span class="keywordflow">return</span> <span class="keyword">self</span>;
<a name="l00105"></a>00105 }
<a name="l00106"></a>00106
<a name="l00107"></a>00107
<a name="l00108"></a>00108 <span class="keywordtype">void</span> CRpnStack::ConstructL()
<a name="l00109"></a>00109 {
<a name="l00110"></a>00110 iTop = 0 ;
<a name="l00111"></a>00111 }
<a name="l00112"></a>00112
<a name="l00113"></a>00113
<a name="l00114"></a>00114 <span class="comment">// stack destructor</span>
<a name="l00115"></a>00115 CRpnStack::~CRpnStack()
<a name="l00116"></a>00116 {
<a name="l00117"></a>00117 <span class="keywordflow">while</span> (!IsEmpty())
<a name="l00118"></a>00118 Pop() ;
<a name="l00119"></a>00119 }
<a name="l00120"></a>00120
<a name="l00121"></a>00121
<a name="l00122"></a>00122 <span class="comment">// stack pop & delete top element</span>
<a name="l00123"></a>00123 TReal CRpnStack::Pop ()
<a name="l00124"></a>00124 {
<a name="l00125"></a>00125 TReal value = iTop->iValue ; <span class="comment">// get return value</span>
<a name="l00126"></a>00126 CRpnStackElement* old = iTop ; <span class="comment">// keep old top of stack pointer</span>
<a name="l00127"></a>00127 iTop = iTop->iNext; <span class="comment">// move top of stack pointer to next element</span>
<a name="l00128"></a>00128 <span class="keyword">delete</span> old ; <span class="comment">// delete old top of stack element</span>
<a name="l00129"></a>00129 old = 0 ; <span class="comment">// don't want old used again</span>
<a name="l00130"></a>00130 <span class="keywordflow">return</span> value ; <span class="comment">// return the value</span>
<a name="l00131"></a>00131 }
<a name="l00132"></a>00132
<a name="l00133"></a>00133
<a name="l00134"></a>00134 <span class="comment">// stack push new element</span>
<a name="l00135"></a>00135 <span class="keywordtype">void</span> CRpnStack::Push (TReal aReal)
<a name="l00136"></a>00136 {
<a name="l00137"></a>00137 TRAPD(err,iTop = CRpnStackElement::NewL(aReal, iTop)) ;
<a name="l00138"></a>00138 <span class="keywordflow">if</span>(err)
<a name="l00139"></a>00139 {
<a name="l00140"></a>00140 <a class="code" href="secureclientandserver_8h.html#a5eadd4429627d82193b37536d4faa03a">_LIT</a>(KFormat2,<span class="stringliteral">"Push failed: leave code=%d"</span>);
<a name="l00141"></a>00141 console->Printf(KFormat2,err);
<a name="l00142"></a>00142 }
<a name="l00143"></a>00143 }
<a name="l00144"></a>00144
<a name="l00145"></a>00145
<a name="l00146"></a>00146 <span class="comment">// stack empty test</span>
<a name="l00147"></a>00147 TBool CRpnStack::IsEmpty ()
<a name="l00148"></a>00148 {
<a name="l00149"></a>00149 <span class="keywordflow">return</span> (iTop == 0) ;
<a name="l00150"></a>00150 }
<a name="l00151"></a>00151
<a name="l00152"></a>00152
<a name="l00154"></a>00154 <span class="comment">// RPN calculator engine class</span>
<a name="l00156"></a>00156 <span class="comment"></span>
<a name="l00157"></a>00157 <span class="keyword">class </span>CRpnCalculator
<a name="l00158"></a>00158 {
<a name="l00159"></a>00159 <span class="keyword">private</span>:
<a name="l00160"></a>00160 <span class="keyword">static</span> TReal GetIntegerPart(TLex& aInput) ;
<a name="l00161"></a>00161 <span class="keyword">static</span> TReal GetFractionalPart(TLex& aInput) ;
<a name="l00162"></a>00162 <span class="keyword">static</span> TInt DealWithNum(CRpnStack* aStack, TLex& aInput) ;
<a name="l00163"></a>00163 <span class="keyword">static</span> TInt RPNCalcEngineL(<span class="keyword">const</span> TDesC& aCommand, TReal& aReturnValue) ;
<a name="l00164"></a>00164 <span class="keyword">static</span> TInt doRPNCalcEngine(TLex& aInput,CRpnStack* stack,TReal& aReturnValue);
<a name="l00165"></a>00165 <span class="keyword">static</span> <span class="keywordtype">void</span> DisplayAnswer(TReal aValue) ;
<a name="l00166"></a>00166 <span class="keyword">static</span> TBool TextInput(TDes& aBuf) ;
<a name="l00167"></a>00167 <span class="keyword">public</span>:
<a name="l00168"></a>00168 <span class="keyword">static</span> <span class="keywordtype">void</span> RunRPNCalculatorL() ;
<a name="l00169"></a>00169 } ;
<a name="l00170"></a>00170
<a name="l00171"></a>00171
<a name="l00173"></a>00173 <span class="comment">// RPN calculator engine : numeric routines</span>
<a name="l00175"></a>00175 <span class="comment"></span>
<a name="l00176"></a>00176 TReal CRpnCalculator::GetIntegerPart(TLex& aInput)
<a name="l00177"></a>00177 <span class="comment">// Finds a UInt. Also used before decimal point for RPN TReal processing</span>
<a name="l00178"></a>00178 {
<a name="l00179"></a>00179 TReal accumulator = 0 ;
<a name="l00180"></a>00180
<a name="l00181"></a>00181 <span class="keywordflow">while</span> ((aInput.Peek()).IsDigit())
<a name="l00182"></a>00182 {
<a name="l00183"></a>00183 accumulator = (accumulator * 10) + ( (TReal)aInput.Get() - (TReal)<span class="charliteral">'0'</span> ) ;
<a name="l00184"></a>00184 }
<a name="l00185"></a>00185 <span class="keywordflow">return</span> accumulator ;
<a name="l00186"></a>00186 }
<a name="l00187"></a>00187
<a name="l00188"></a>00188
<a name="l00189"></a>00189 TReal CRpnCalculator::GetFractionalPart(TLex& aInput)
<a name="l00190"></a>00190 <span class="comment">// Finds a UInt. Used after decimal point for RPN TReal processing</span>
<a name="l00191"></a>00191 {
<a name="l00192"></a>00192 TReal accumulator = 0 ;
<a name="l00193"></a>00193 TReal multiplier = 0.1 ;
<a name="l00194"></a>00194
<a name="l00195"></a>00195 <span class="keywordflow">while</span> ((aInput.Peek()).IsDigit())
<a name="l00196"></a>00196 {
<a name="l00197"></a>00197 accumulator += ( (TReal)aInput.Get() - (TReal)<span class="charliteral">'0'</span> ) * multiplier ;
<a name="l00198"></a>00198 multiplier /= 10 ;
<a name="l00199"></a>00199 }
<a name="l00200"></a>00200 <span class="keywordflow">return</span> accumulator ;
<a name="l00201"></a>00201 }
<a name="l00202"></a>00202
<a name="l00203"></a>00203
<a name="l00204"></a>00204 TInt CRpnCalculator::DealWithNum(CRpnStack* aStack, TLex& aInput)
<a name="l00205"></a>00205 <span class="comment">// VERY basic scanning to extract and push a (Uint or real) number.</span>
<a name="l00206"></a>00206 {
<a name="l00207"></a>00207 TBool negative = EFalse ;
<a name="l00208"></a>00208 TReal answer = 0 ;
<a name="l00209"></a>00209 TLexMark startMark ;
<a name="l00210"></a>00210
<a name="l00211"></a>00211 <span class="comment">// need something to parse</span>
<a name="l00212"></a>00212 <span class="keywordflow">if</span> (aInput.Eos())
<a name="l00213"></a>00213 <span class="keywordflow">return</span> KErrNotFound ;
<a name="l00214"></a>00214 <span class="keywordflow">if</span> (!(aInput.Peek().IsDigit() || (aInput.Peek() == <span class="charliteral">'.'</span>) ) )
<a name="l00215"></a>00215 <span class="keywordflow">return</span> KErrNotFound ;
<a name="l00216"></a>00216
<a name="l00217"></a>00217 <span class="comment">// mark where we are, so can unwind</span>
<a name="l00218"></a>00218 aInput.Mark(startMark) ;
<a name="l00219"></a>00219
<a name="l00220"></a>00220 <span class="comment">// deal with sign</span>
<a name="l00221"></a>00221 <span class="keywordflow">if</span> (aInput.Peek() == <span class="charliteral">'+'</span>)
<a name="l00222"></a>00222 aInput.Inc() ;
<a name="l00223"></a>00223 <span class="keywordflow">if</span> (aInput.Peek() == <span class="charliteral">'-'</span>)
<a name="l00224"></a>00224 {
<a name="l00225"></a>00225 aInput.Inc() ;
<a name="l00226"></a>00226 negative = ETrue ;
<a name="l00227"></a>00227 }
<a name="l00228"></a>00228
<a name="l00229"></a>00229 <span class="comment">// check there's something to parse</span>
<a name="l00230"></a>00230 <span class="keywordflow">if</span> (aInput.Eos())
<a name="l00231"></a>00231 <span class="keywordflow">return</span> KErrNotFound ;
<a name="l00232"></a>00232
<a name="l00233"></a>00233 <span class="comment">// get number (may be complete integer or first part of a real)</span>
<a name="l00234"></a>00234 <span class="keywordflow">if</span> ((aInput.Peek()).IsDigit())
<a name="l00235"></a>00235 answer = CRpnCalculator::GetIntegerPart(aInput) ;
<a name="l00236"></a>00236
<a name="l00237"></a>00237 <span class="comment">// negate if necessary</span>
<a name="l00238"></a>00238 <span class="keywordflow">if</span> (negative)
<a name="l00239"></a>00239 answer *= -1 ;
<a name="l00240"></a>00240
<a name="l00241"></a>00241 <span class="comment">// look for decimal point - if found, parse real number</span>
<a name="l00242"></a>00242 <span class="keywordflow">if</span> (aInput.Peek() == <span class="charliteral">'.'</span>)
<a name="l00243"></a>00243 { <span class="comment">// may be dealing with real number.</span>
<a name="l00244"></a>00244 aInput.Inc() ;
<a name="l00245"></a>00245 <span class="keywordflow">if</span> (!(aInput.Peek()).IsDigit())
<a name="l00246"></a>00246 { <span class="comment">// found non-digit after decimal point. Error, so rewind & exit</span>
<a name="l00247"></a>00247 aInput.UnGetToMark(startMark) ;
<a name="l00248"></a>00248 <span class="keywordflow">return</span> KErrCancel ;
<a name="l00249"></a>00249 }
<a name="l00250"></a>00250 <span class="comment">// now must parse digit(s) after decimal point</span>
<a name="l00251"></a>00251 answer += CRpnCalculator::GetFractionalPart(aInput) ;
<a name="l00252"></a>00252 aStack->Push(answer) ;
<a name="l00253"></a>00253 <span class="keywordflow">return</span> KErrNone ;
<a name="l00254"></a>00254 }
<a name="l00255"></a>00255 <span class="keywordflow">else</span>
<a name="l00256"></a>00256 { <span class="comment">// dealing with integer </span>
<a name="l00257"></a>00257 aStack->Push(answer) ;
<a name="l00258"></a>00258 <span class="keywordflow">return</span> KErrNone ;
<a name="l00259"></a>00259 }
<a name="l00260"></a>00260 }
<a name="l00261"></a>00261
<a name="l00262"></a>00262
<a name="l00264"></a>00264 <span class="comment">// Main body of the RPN calculator engine : calculator</span>
<a name="l00266"></a>00266 <span class="comment"></span>
<a name="l00267"></a>00267 TInt CRpnCalculator::doRPNCalcEngine(TLex& aInput,CRpnStack* stack,TReal& aReturnValue)
<a name="l00268"></a>00268 {
<a name="l00269"></a>00269 <span class="comment">// extract a number if possible & push</span>
<a name="l00270"></a>00270 <span class="comment">// extract token, perform operation & push result</span>
<a name="l00271"></a>00271 <span class="comment">// if token is '=' or at end of string, pop & print value</span>
<a name="l00272"></a>00272 TInt Err = KErrNone;
<a name="l00273"></a>00273 TReal operand1 = 0;
<a name="l00274"></a>00274 TReal operand2 = 0 ;
<a name="l00275"></a>00275 TReal memory = 0 ;
<a name="l00276"></a>00276
<a name="l00277"></a>00277 <span class="keywordflow">do</span>
<a name="l00278"></a>00278 {
<a name="l00279"></a>00279 aInput.SkipSpace() ;
<a name="l00280"></a>00280
<a name="l00281"></a>00281 <span class="keywordflow">if</span> (CRpnCalculator::DealWithNum(stack, aInput)== KErrNone) ; <span class="comment">// parse for number </span>
<a name="l00282"></a>00282
<a name="l00283"></a>00283 <span class="comment">/* above line can be replaced by the following equivalent code:</span>
<a name="l00284"></a>00284 <span class="comment"> </span>
<a name="l00285"></a>00285 <span class="comment"> if (aInput.Val(extractReal) == KErrNone)</span>
<a name="l00286"></a>00286 <span class="comment"> stack->Push(extractReal) ;</span>
<a name="l00287"></a>00287 <span class="comment"> else if (aInput.Val(extractUint) == KErrNone)</span>
<a name="l00288"></a>00288 <span class="comment"> stack->Push(TReal(extractUint)) ;</span>
<a name="l00289"></a>00289 <span class="comment"> */</span>
<a name="l00290"></a>00290
<a name="l00291"></a>00291 <span class="keywordflow">else</span> <span class="keywordflow">switch</span> ( aInput.Get() )
<a name="l00292"></a>00292 {
<a name="l00293"></a>00293 <span class="keywordflow">case</span><span class="charliteral">'+'</span> :
<a name="l00294"></a>00294 <span class="keywordflow">if</span> (!stack->IsEmpty()) operand2 = stack->Pop() ; <span class="keywordflow">else</span> Err = KErrGeneral ;
<a name="l00295"></a>00295 <span class="keywordflow">if</span> (!stack->IsEmpty()) operand1 = stack->Pop() ; <span class="keywordflow">else</span> Err = KErrGeneral;
<a name="l00296"></a>00296 <span class="keywordflow">if</span> (Err==KErrNone) stack->Push (operand1 + operand2) ;
<a name="l00297"></a>00297 break ;
<a name="l00298"></a>00298
<a name="l00299"></a>00299 <span class="keywordflow">case</span><span class="charliteral">'-'</span> :
<a name="l00300"></a>00300 <span class="keywordflow">if</span> (!stack->IsEmpty()) operand2 = stack->Pop() ; <span class="keywordflow">else</span> Err = KErrGeneral ;
<a name="l00301"></a>00301 <span class="keywordflow">if</span> (!stack->IsEmpty()) operand1 = stack->Pop() ; <span class="keywordflow">else</span> Err = KErrGeneral;
<a name="l00302"></a>00302 <span class="keywordflow">if</span> (Err==KErrNone) stack->Push (operand1 - operand2) ;
<a name="l00303"></a>00303 break ;
<a name="l00304"></a>00304
<a name="l00305"></a>00305 <span class="keywordflow">case</span> <span class="charliteral">'*'</span> :
<a name="l00306"></a>00306 <span class="keywordflow">if</span> (!stack->IsEmpty()) operand2 = stack->Pop() ; <span class="keywordflow">else</span> Err = KErrGeneral ;
<a name="l00307"></a>00307 <span class="keywordflow">if</span> (!stack->IsEmpty()) operand1 = stack->Pop() ; <span class="keywordflow">else</span> Err = KErrGeneral;
<a name="l00308"></a>00308 <span class="keywordflow">if</span> (Err==KErrNone) stack->Push (operand1 * operand2) ;
<a name="l00309"></a>00309 break ;
<a name="l00310"></a>00310
<a name="l00311"></a>00311 <span class="keywordflow">case</span><span class="charliteral">'/'</span> :
<a name="l00312"></a>00312 <span class="keywordflow">if</span> (!stack->IsEmpty()) operand2 = stack->Pop() ; <span class="keywordflow">else</span> Err = KErrGeneral ;
<a name="l00313"></a>00313 <span class="keywordflow">if</span> (!stack->IsEmpty()) operand1 = stack->Pop() ; <span class="keywordflow">else</span> Err = KErrGeneral;
<a name="l00314"></a>00314 <span class="keywordflow">if</span> (Err==KErrNone) stack->Push (operand1 / operand2) ;
<a name="l00315"></a>00315 break ;
<a name="l00316"></a>00316
<a name="l00317"></a>00317 <span class="keywordflow">case</span> <span class="charliteral">'='</span> :
<a name="l00318"></a>00318 <span class="keywordflow">if</span> ( !(stack->IsEmpty() ) )
<a name="l00319"></a>00319 { aReturnValue = stack->Pop() ;
<a name="l00320"></a>00320 <span class="keywordflow">return</span> KErrNone ;
<a name="l00321"></a>00321 }
<a name="l00322"></a>00322 <span class="keywordflow">else</span> <span class="keywordflow">return</span> KErrArgument ;
<a name="l00323"></a>00323
<a name="l00324"></a>00324 <span class="comment">// not found a valid one-character symbol, try key words...</span>
<a name="l00325"></a>00325 <span class="keywordflow">default</span> :
<a name="l00326"></a>00326 <span class="keywordflow">if</span> (aInput.Offset() > 0) <span class="comment">// if not at start of line</span>
<a name="l00327"></a>00327 aInput.UnGet() ; <span class="comment">// restore 'got' character</span>
<a name="l00328"></a>00328
<a name="l00329"></a>00329 aInput.Mark() ; <span class="comment">// remember where we are</span>
<a name="l00330"></a>00330 aInput.SkipCharacters() ; <span class="comment">// move to end of character token</span>
<a name="l00331"></a>00331
<a name="l00332"></a>00332
<a name="l00333"></a>00333 <span class="keywordflow">if</span> ( aInput.TokenLength() != 0 ) <span class="comment">// if valid potential token</span>
<a name="l00334"></a>00334 {
<a name="l00335"></a>00335 <a class="code" href="secureclientandserver_8h.html#a5eadd4429627d82193b37536d4faa03a">_LIT</a>(KTxtMEMSET,<span class="stringliteral">"MEMSET"</span>);
<a name="l00336"></a>00336 <a class="code" href="secureclientandserver_8h.html#a5eadd4429627d82193b37536d4faa03a">_LIT</a>(KTxtMEMGET,<span class="stringliteral">"MEMGET"</span>);
<a name="l00337"></a>00337 TPtrC token = aInput.MarkedToken() ; <span class="comment">// extract token</span>
<a name="l00338"></a>00338 <span class="keywordflow">if</span> ( token.CompareF(KTxtMEMSET) == 0)
<a name="l00339"></a>00339 {
<a name="l00340"></a>00340 <span class="keywordflow">if</span> ( !(stack->IsEmpty()) ) <span class="comment">// MEMSET - store top stack element</span>
<a name="l00341"></a>00341 memory = stack->Pop() ;
<a name="l00342"></a>00342 <span class="keywordflow">if</span> ( stack->IsEmpty() ) <span class="comment">// valid command, but empty stack will cause error, so</span>
<a name="l00343"></a>00343 stack->Push(memory) ;
<a name="l00344"></a>00344 }
<a name="l00345"></a>00345 <span class="keywordflow">else</span> <span class="keywordflow">if</span> ( token.CompareF(KTxtMEMGET) == 0)
<a name="l00346"></a>00346 stack->Push (memory) ; <span class="comment">// MEMGET - push memory value</span>
<a name="l00347"></a>00347 <span class="keywordflow">else</span>
<a name="l00348"></a>00348 <span class="keywordflow">return</span> KErrNotSupported ; <span class="comment">// unrecognised token</span>
<a name="l00349"></a>00349 }
<a name="l00350"></a>00350 <span class="keywordflow">else</span> <span class="comment">// exit - can't be anything else</span>
<a name="l00351"></a>00351 {
<a name="l00352"></a>00352 <span class="keywordflow">return</span> KErrGeneral ;
<a name="l00353"></a>00353 }
<a name="l00354"></a>00354 } ; <span class="comment">// end switch</span>
<a name="l00355"></a>00355 <span class="keywordflow">if</span> (Err == KErrGeneral)
<a name="l00356"></a>00356 <span class="comment">// error in expression (usually as there aren't 2 stack elements for token to operate on)</span>
<a name="l00357"></a>00357 <span class="keywordflow">return</span> KErrArgument ;
<a name="l00358"></a>00358
<a name="l00359"></a>00359 } <span class="keywordflow">while</span> (!aInput.Eos()) ;
<a name="l00360"></a>00360
<a name="l00361"></a>00361 <span class="keywordflow">if</span> ( !(stack->IsEmpty() ) )
<a name="l00362"></a>00362 {
<a name="l00363"></a>00363 aReturnValue = stack->Pop() ;
<a name="l00364"></a>00364 <span class="keywordflow">return</span> KErrNone ;
<a name="l00365"></a>00365 }
<a name="l00366"></a>00366 <span class="keywordflow">else</span> <span class="keywordflow">return</span> KErrArgument ;
<a name="l00367"></a>00367 }
<a name="l00368"></a>00368
<a name="l00369"></a>00369
<a name="l00370"></a>00370
<a name="l00372"></a>00372 <span class="comment">// RPN calculator engine : calculator</span>
<a name="l00374"></a>00374 <span class="comment"></span>
<a name="l00375"></a>00375 TInt CRpnCalculator::RPNCalcEngineL(<span class="keyword">const</span> TDesC& aCommand, TReal& aReturnValue)
<a name="l00376"></a>00376 {
<a name="l00377"></a>00377 TInt ret;
<a name="l00378"></a>00378 TLex input(aCommand);
<a name="l00379"></a>00379
<a name="l00380"></a>00380 CRpnStack* stack = CRpnStack::NewL();
<a name="l00381"></a>00381 CleanupStack::PushL(stack);
<a name="l00382"></a>00382 ret = CRpnCalculator::doRPNCalcEngine(input,stack,aReturnValue);
<a name="l00383"></a>00383 CleanupStack::PopAndDestroy();
<a name="l00384"></a>00384 <span class="keywordflow">return</span> ret;
<a name="l00385"></a>00385 }
<a name="l00386"></a>00386
<a name="l00387"></a>00387
<a name="l00388"></a>00388
<a name="l00390"></a>00390 <span class="comment">// RPN calculator UI : display routines</span>
<a name="l00392"></a>00392 <span class="comment"></span>
<a name="l00393"></a>00393 <span class="keywordtype">void</span> CRpnCalculator::DisplayAnswer(TReal aValue)
<a name="l00394"></a>00394 {
<a name="l00395"></a>00395 TRealFormat format ;
<a name="l00396"></a>00396 TBuf<0x100> convertRealToString;
<a name="l00397"></a>00397
<a name="l00398"></a>00398 <span class="comment">// want a TLex from the value</span>
<a name="l00399"></a>00399
<a name="l00400"></a>00400 <span class="keywordflow">if</span> (convertRealToString.Num(aValue,format) < KErrNone ) <span class="comment">// if -ve, is an error, not a string length </span>
<a name="l00401"></a>00401 console->Printf(KTxtErrInExpress);
<a name="l00402"></a>00402 <span class="keywordflow">else</span>
<a name="l00403"></a>00403 {
<a name="l00404"></a>00404 convertRealToString.ZeroTerminate();
<a name="l00405"></a>00405
<a name="l00406"></a>00406 TLex string(convertRealToString) ;
<a name="l00407"></a>00407 <span class="comment">// got a TLex</span>
<a name="l00408"></a>00408
<a name="l00409"></a>00409 TLexMark start ;
<a name="l00410"></a>00410 <span class="keywordtype">string</span>.Mark (start) ; <span class="comment">// remember start of string position</span>
<a name="l00411"></a>00411
<a name="l00412"></a>00412 <span class="comment">// run through string, setting 'end' to last digit found</span>
<a name="l00413"></a>00413 <span class="keywordflow">while</span> (!<span class="keywordtype">string</span>.Eos() )
<a name="l00414"></a>00414 {
<a name="l00415"></a>00415 <span class="keywordflow">if</span> ( !(<span class="keywordtype">string</span>.Get() == <span class="charliteral">'0'</span>) ) <span class="keywordtype">string</span>.Mark() ;
<a name="l00416"></a>00416 }
<a name="l00417"></a>00417
<a name="l00418"></a>00418 <span class="keywordtype">string</span>.UnGetToMark() ; <span class="comment">// reset next character pointer to last digit</span>
<a name="l00419"></a>00419 <span class="comment">// if Mark points to decimal point and not at Eos (i.e. a zero follows), include the zero</span>
<a name="l00420"></a>00420 <span class="keywordflow">if</span> ( <span class="keywordtype">string</span>.Get() == <span class="charliteral">'.'</span> && !<span class="keywordtype">string</span>.Eos() )
<a name="l00421"></a>00421 <span class="keywordtype">string</span>.Mark() ;
<a name="l00422"></a>00422
<a name="l00423"></a>00423 <span class="comment">// display spaces after entered line</span>
<a name="l00424"></a>00424 <a class="code" href="secureclientandserver_8h.html#a5eadd4429627d82193b37536d4faa03a">_LIT</a>(KTxtSpaces,<span class="stringliteral">" "</span>);
<a name="l00425"></a>00425 console->Write(KTxtSpaces) ;
<a name="l00426"></a>00426 <span class="comment">// set Mark to start of string and display answer</span>
<a name="l00427"></a>00427 console->Write( <span class="keywordtype">string</span>.MarkedToken(start) ) ;
<a name="l00428"></a>00428 }
<a name="l00429"></a>00429 }
<a name="l00430"></a>00430
<a name="l00431"></a>00431
<a name="l00433"></a>00433 <span class="comment">// RPN calculator UI : line input routine (adapted from tuiedit)</span>
<a name="l00435"></a>00435 <span class="comment"></span>
<a name="l00436"></a>00436 <a class="code" href="secureclientandserver_8h.html#a5eadd4429627d82193b37536d4faa03a">_LIT</a>(KTxtBackSlashSeven,<span class="stringliteral">"\7"</span>);
<a name="l00437"></a>00437 <a class="code" href="secureclientandserver_8h.html#a5eadd4429627d82193b37536d4faa03a">_LIT</a>(KTxtCursor,<span class="stringliteral">"_"</span>);
<a name="l00438"></a>00438
<a name="l00439"></a>00439 TBool CRpnCalculator::TextInput(TDes& aBuf)
<a name="l00440"></a>00440 {
<a name="l00441"></a>00441 TInt pos;
<a name="l00442"></a>00442
<a name="l00443"></a>00443 pos = 0;
<a name="l00444"></a>00444 aBuf.Zero();
<a name="l00445"></a>00445 console->SetPos(0);
<a name="l00446"></a>00446 console->Write(KTxtCursor) ; <span class="comment">// "cursor"</span>
<a name="l00447"></a>00447 console->SetPos(0);
<a name="l00448"></a>00448
<a name="l00449"></a>00449 FOREVER
<a name="l00450"></a>00450 {
<a name="l00451"></a>00451 TChar gChar=console->Getch();
<a name="l00452"></a>00452 <span class="keywordflow">switch</span> (gChar)
<a name="l00453"></a>00453 {
<a name="l00454"></a>00454 <span class="keywordflow">case</span> EKeyEscape:
<a name="l00455"></a>00455 <span class="keywordflow">return</span> (EFalse);
<a name="l00456"></a>00456 <span class="keywordflow">case</span> EKeyEnter:
<a name="l00457"></a>00457 <span class="keywordflow">return</span> (ETrue);
<a name="l00458"></a>00458 <span class="keywordflow">case</span> EKeyBackspace:
<a name="l00459"></a>00459 <span class="keywordflow">if</span> (pos)
<a name="l00460"></a>00460 {
<a name="l00461"></a>00461 pos--;
<a name="l00462"></a>00462 aBuf.Delete(pos,1);
<a name="l00463"></a>00463 }
<a name="l00464"></a>00464 <span class="keywordflow">break</span>;
<a name="l00465"></a>00465 <span class="keywordflow">default</span>:
<a name="l00466"></a>00466 <span class="keywordflow">if</span> (!gChar.IsPrint())
<a name="l00467"></a>00467 <span class="keywordflow">break</span>;
<a name="l00468"></a>00468 <span class="keywordflow">else</span>
<a name="l00469"></a>00469 <span class="keywordflow">if</span> ((aBuf.Length()<KMaxCalcCommandBuffer)&&(pos<KDefaultConsWidth-3))
<a name="l00470"></a>00470 {
<a name="l00471"></a>00471 TBuf<0x02> b;
<a name="l00472"></a>00472 b.Append(gChar);
<a name="l00473"></a>00473 aBuf.Insert(pos++,b);
<a name="l00474"></a>00474 }
<a name="l00475"></a>00475 <span class="keywordflow">else</span>
<a name="l00476"></a>00476 {
<a name="l00477"></a>00477 console->Write(KTxtBackSlashSeven);
<a name="l00478"></a>00478 <span class="keywordflow">break</span>;
<a name="l00479"></a>00479 }
<a name="l00480"></a>00480 }
<a name="l00481"></a>00481 console->SetPos(pos) ;
<a name="l00482"></a>00482 console->ClearToEndOfLine();
<a name="l00483"></a>00483 console->SetPos(0);
<a name="l00484"></a>00484 console->Write(aBuf);
<a name="l00485"></a>00485 console->Write(KTxtCursor) ; <span class="comment">// "cursor"</span>
<a name="l00486"></a>00486 console->SetPos(pos);
<a name="l00487"></a>00487 }
<a name="l00488"></a>00488 }
<a name="l00489"></a>00489
<a name="l00490"></a>00490
<a name="l00492"></a>00492 <span class="comment">// finally the RPN calculator's driver code</span>
<a name="l00494"></a>00494 <span class="comment"></span>
<a name="l00495"></a>00495 <a class="code" href="secureclientandserver_8h.html#a5eadd4429627d82193b37536d4faa03a">_LIT</a>(KTxtStartingRPNCalc,<span class="stringliteral">"Starting RPN Calculator\n\n"</span>);
<a name="l00496"></a>00496 <a class="code" href="secureclientandserver_8h.html#a5eadd4429627d82193b37536d4faa03a">_LIT</a>(KTxtNewLine,<span class="stringliteral">" \n"</span>);
<a name="l00497"></a>00497 <a class="code" href="secureclientandserver_8h.html#a5eadd4429627d82193b37536d4faa03a">_LIT</a>(KTxtInvite,<span class="stringliteral">"Type in a Reverse Polish\nexpression.\nPress ENTER to evaluate it\nPress ESC to end\n"</span>);
<a name="l00498"></a>00498
<a name="l00499"></a>00499
<a name="l00500"></a>00500
<a name="l00501"></a>00501 <span class="keywordtype">void</span> CRpnCalculator::RunRPNCalculatorL()
<a name="l00502"></a>00502 {
<a name="l00503"></a>00503 TBuf<KMaxCalcCommandBuffer> command;
<a name="l00504"></a>00504
<a name="l00505"></a>00505 console->Printf(KTxtStartingRPNCalc);
<a name="l00506"></a>00506 console->Printf(KTxtInvite);
<a name="l00507"></a>00507
<a name="l00508"></a>00508 <span class="keywordflow">while</span> (CRpnCalculator::TextInput(command) )
<a name="l00509"></a>00509 {
<a name="l00510"></a>00510 TReal answer;
<a name="l00511"></a>00511
<a name="l00512"></a>00512 <span class="keywordflow">if</span> (CRpnCalculator::RPNCalcEngineL(command, answer) == KErrNone )
<a name="l00513"></a>00513 CRpnCalculator::DisplayAnswer(answer) ;
<a name="l00514"></a>00514 <span class="keywordflow">else</span>
<a name="l00515"></a>00515 console->Printf(KTxtErrInExpress) ;
<a name="l00516"></a>00516
<a name="l00517"></a>00517 console->Printf(KTxtNewLine) ;
<a name="l00518"></a>00518 console->Printf(KTxtInvite);
<a name="l00519"></a>00519 }
<a name="l00520"></a>00520 }
<a name="l00521"></a>00521
<a name="l00522"></a>00522
<a name="l00524"></a>00524 <span class="comment">// This section deals with Symbian platform initialisation and ensuring we have a console active</span>
<a name="l00526"></a>00526 <span class="comment"></span>
<a name="l00527"></a>00527
<a name="l00528"></a>00528 <span class="keywordtype">void</span> SetupConsoleL();
<a name="l00529"></a>00529
<a name="l00530"></a>00530 <a class="code" href="secureclientandserver_8h.html#a5eadd4429627d82193b37536d4faa03a">_LIT</a>(KTxtRPNCalcErr,<span class="stringliteral">"RPN Calculator example error"</span>);
<a name="l00531"></a>00531
<a name="l00532"></a>00532 GLDEF_C TInt E32Main() <span class="comment">// main function called by E32</span>
<a name="l00533"></a>00533 {
<a name="l00534"></a>00534 CTrapCleanup* cleanup=CTrapCleanup::New(); <span class="comment">// get clean-up stack</span>
<a name="l00535"></a>00535 TRAPD(error,SetupConsoleL()); <span class="comment">// more initialization, then do example</span>
<a name="l00536"></a>00536 __ASSERT_ALWAYS(!error,User::Panic(KTxtRPNCalcErr,error));
<a name="l00537"></a>00537 <span class="keyword">delete</span> cleanup; <span class="comment">// destroy clean-up stack</span>
<a name="l00538"></a>00538 <span class="keywordflow">return</span> 0; <span class="comment">// and return</span>
<a name="l00539"></a>00539 }
<a name="l00540"></a>00540
<a name="l00541"></a>00541
<a name="l00542"></a>00542 <span class="keywordtype">void</span> SetupConsoleL() <span class="comment">// initialize and call example code under cleanup stack</span>
<a name="l00543"></a>00543 {
<a name="l00544"></a>00544 <a class="code" href="secureclientandserver_8h.html#a5eadd4429627d82193b37536d4faa03a">_LIT</a>(KTxtIntro,<span class="stringliteral">"eulexrpn - RPN Calculator"</span>);
<a name="l00545"></a>00545 <a class="code" href="secureclientandserver_8h.html#a5eadd4429627d82193b37536d4faa03a">_LIT</a>(KFormat1,<span class="stringliteral">"failed: leave code=%d"</span>);
<a name="l00546"></a>00546 <a class="code" href="secureclientandserver_8h.html#a5eadd4429627d82193b37536d4faa03a">_LIT</a>(KTxtPressAnyKey,<span class="stringliteral">"[Press any key to exit]"</span>);
<a name="l00547"></a>00547
<a name="l00548"></a>00548 console=Console::NewL(KTxtIntro,TSize(KConsFullScreen,KConsFullScreen));
<a name="l00549"></a>00549 CleanupStack::PushL(console);
<a name="l00550"></a>00550 TRAPD(error, CRpnCalculator::RunRPNCalculatorL()); <span class="comment">// perform example function</span>
<a name="l00551"></a>00551 <span class="keywordflow">if</span> (error)
<a name="l00552"></a>00552 console->Printf(KFormat1, error);
<a name="l00553"></a>00553 console->Printf(KTxtPressAnyKey);
<a name="l00554"></a>00554 console->Getch(); <span class="comment">// get and ignore character</span>
<a name="l00555"></a>00555 CleanupStack::PopAndDestroy(); <span class="comment">// close console</span>
<a name="l00556"></a>00556 }
<a name="l00557"></a>00557
<a name="l00558"></a>00558
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