Symbian3/Examples/guid-6013a680-57f9-415b-8851-c4fa63356636/_buffer_8cpp-source.html
week 10 bug fix submission: Bug 1892, Bug 1897, Bug 1319. Also 3 or 4 documents were found to contain code blocks with SFL, which has been fixed. Partial fix for broken links, links to Forum Nokia, and the 'Symbian platform' terminology issues.
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<h1>examples/Base/BufsAndStrings/Desc/Buffer/Buffer.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">// Examples to demonstrate the basic ideas of</span>
<a name="l00015"></a>00015 <span class="comment">// buffer descriptors.</span>
<a name="l00016"></a>00016 <span class="comment">//</span>
<a name="l00017"></a>00017
<a name="l00018"></a>00018 <span class="preprocessor">#include "CommonFramework.h"</span>
<a name="l00019"></a>00019
<a name="l00020"></a>00020 <span class="comment">//</span>
<a name="l00021"></a>00021 <span class="comment">// Common literal text</span>
<a name="l00022"></a>00022 <span class="comment">//</span>
<a name="l00023"></a>00023 _LIT(KTxtHelloWorld,<span class="stringliteral">"Hello World!"</span>);
<a name="l00024"></a>00024 _LIT(KTxtRepText,<span class="stringliteral">"Replacement text"</span>);
<a name="l00025"></a>00025 _LIT(KTxtTBufC,<span class="stringliteral">"TBufC: "</span>);
<a name="l00026"></a>00026 _LIT(KTxtTPtr,<span class="stringliteral">"TPtr: "</span>);
<a name="l00027"></a>00027
<a name="l00028"></a>00028 <span class="comment">//</span>
<a name="l00029"></a>00029 <span class="comment">// Common Format strings</span>
<a name="l00030"></a>00030 <span class="comment">//</span>
<a name="l00031"></a>00031 _LIT(KCommonFormat2,<span class="stringliteral">"\"%S\"; "</span>);
<a name="l00032"></a>00032 _LIT(KCommonFormat3,<span class="stringliteral">"Descriptor at %x; Ptr()=%x; "</span>);
<a name="l00033"></a>00033 _LIT(KCommonFormat6,<span class="stringliteral">"\"%S\"; Ptr()=%x; Length()=%d; Size()=%d\n"</span>);
<a name="l00034"></a>00034 _LIT(KCommonFormat7,<span class="stringliteral">"\"%S\"; Ptr()=%x; Length()=%d; Size()=%d; "</span>);
<a name="l00035"></a>00035 _LIT(KCommonFormat8,<span class="stringliteral">"\nMaxLength()=%d\n"</span>);
<a name="l00036"></a>00036 _LIT(KCommonFormat9,<span class="stringliteral">"Length()=%d; Size()=%d;\n"</span>);
<a name="l00037"></a>00037 _LIT(KCommonFormat10,<span class="stringliteral">"MaxLength()=%d\n"</span>);
<a name="l00038"></a>00038
<a name="l00039"></a>00039
<a name="l00040"></a>00040 LOCAL_C <span class="keywordtype">void</span> doExampleL()
<a name="l00041"></a>00041 {
<a name="l00042"></a>00042 <span class="comment">// Set up an area and initialise to a </span>
<a name="l00043"></a>00043 <span class="comment">// C style string (including the NULL).</span>
<a name="l00044"></a>00044 TText cstr[13] = {<span class="charliteral">'H'</span>, <span class="charliteral">'e'</span> ,<span class="charliteral">'l'</span> ,<span class="charliteral">'l'</span> ,<span class="charliteral">'o'</span>, <span class="charliteral">' '</span>,
<a name="l00045"></a>00045 <span class="charliteral">'W'</span>, <span class="charliteral">'o'</span>,<span class="charliteral">'r'</span>, <span class="charliteral">'l'</span>, <span class="charliteral">'d'</span>, <span class="charliteral">'!'</span>, <span class="charliteral">'\0'</span>};
<a name="l00046"></a>00046
<a name="l00047"></a>00047 <span class="comment">// Construct a TBufC using the NULL </span>
<a name="l00048"></a>00048 <span class="comment">// terminated string in cstr to initialise</span>
<a name="l00049"></a>00049 <span class="comment">// it.</span>
<a name="l00050"></a>00050 TBufC<16> bufc1(&cstr[0]);
<a name="l00051"></a>00051
<a name="l00052"></a>00052 <span class="comment">// Look at the address of the C string</span>
<a name="l00053"></a>00053 _LIT(KFormat1,<span class="stringliteral">"C string at %x; \n"</span>);
<a name="l00054"></a>00054 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KFormat1,&cstr[0]);
<a name="l00055"></a>00055
<a name="l00056"></a>00056 <span class="comment">// Look at: </span>
<a name="l00057"></a>00057 <span class="comment">// 1. Descriptor content</span>
<a name="l00058"></a>00058 <span class="comment">// 2. Address of descriptor</span>
<a name="l00059"></a>00059 <span class="comment">// 3. Address of descriptor data area</span>
<a name="l00060"></a>00060 <span class="comment">// 4. Length of descriptor</span>
<a name="l00061"></a>00061 <span class="comment">// 5. Size of descriptor</span>
<a name="l00062"></a>00062 <span class="comment">// </span>
<a name="l00063"></a>00063 <span class="comment">// Address of descriptor data area is </span>
<a name="l00064"></a>00064 <span class="comment">// different from the address of cstr but</span>
<a name="l00065"></a>00065 <span class="comment">// is offset 4 from the start of the </span>
<a name="l00066"></a>00066 <span class="comment">// descriptor itself.</span>
<a name="l00067"></a>00067 <span class="comment">//</span>
<a name="l00068"></a>00068 <span class="comment">// Descriptor length is 12.</span>
<a name="l00069"></a>00069 <span class="comment">//</span>
<a name="l00070"></a>00070 <span class="comment">// The template parameter value defines </span>
<a name="l00071"></a>00071 <span class="comment">// the length of the descriptor data area </span>
<a name="l00072"></a>00072 <span class="comment">// and, therefore, governs its size </span>
<a name="l00073"></a>00073 <span class="comment">// (depending on the build variant).</span>
<a name="l00074"></a>00074 <span class="comment">// Size of data is 24</span>
<a name="l00075"></a>00075 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KCommonFormat2,&bufc1);
<a name="l00076"></a>00076 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KCommonFormat3,&bufc1,bufc1.Ptr());
<a name="l00077"></a>00077 _LIT(KFormat4,<span class="stringliteral">"Length()=%d; Size()=%d\n"</span>);
<a name="l00078"></a>00078 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KFormat4,bufc1.Length(),bufc1.Size());
<a name="l00079"></a>00079
<a name="l00080"></a>00080 <span class="comment">// If the TBufC is to hold string data on</span>
<a name="l00081"></a>00081 <span class="comment">// construction, use a _LIT macro.</span>
<a name="l00082"></a>00082 TBufC<16> bufc2(KTxtHelloWorld);
<a name="l00083"></a>00083
<a name="l00084"></a>00084 <span class="comment">// Cannot modify existing data but can replace</span>
<a name="l00085"></a>00085 <span class="comment">// it entirely using assignment operator. </span>
<a name="l00086"></a>00086 <span class="comment">// The replacement text must not have a length </span>
<a name="l00087"></a>00087 <span class="comment">// greater than 16</span>
<a name="l00088"></a>00088 bufc2 = KTxtRepText;
<a name="l00089"></a>00089 _LIT(KFormat5,<span class="stringliteral">"\"%S\"; Length()=%d; Size()=%d\n"</span>);
<a name="l00090"></a>00090 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KFormat5,&bufc2,bufc2.Length(),bufc2.Size());
<a name="l00091"></a>00091
<a name="l00092"></a>00092 <span class="comment">// Replacing text which has a length > 16</span>
<a name="l00093"></a>00093 <span class="comment">// causes panic !!</span>
<a name="l00094"></a>00094 <span class="comment">// </span>
<a name="l00095"></a>00095 <span class="comment">// Remove the "//" marks on the next two lines</span>
<a name="l00096"></a>00096 <span class="comment">// to see this happen</span>
<a name="l00097"></a>00097 <span class="comment">//_LIT(KTxtRepTextPanic,"Text replacement causes panic");</span>
<a name="l00098"></a>00098 <span class="comment">//bufc2 = KTxtRepTextPanic;</span>
<a name="l00099"></a>00099
<a name="l00100"></a>00100
<a name="l00101"></a>00101 <span class="comment">// The Des() function returns a TPtr to the</span>
<a name="l00102"></a>00102 <span class="comment">// TBufC.</span>
<a name="l00103"></a>00103 <span class="comment">// The TBufC data can be changed through </span>
<a name="l00104"></a>00104 <span class="comment">// the TPtr.</span>
<a name="l00105"></a>00105 <span class="comment">// The maximum length of the TPtr is the </span>
<a name="l00106"></a>00106 <span class="comment">// value of the TBufC template parameter,</span>
<a name="l00107"></a>00107 <span class="comment">// i.e. 16 </span>
<a name="l00108"></a>00108
<a name="l00109"></a>00109 bufc2 = KTxtHelloWorld;
<a name="l00110"></a>00110 TPtr ptr = bufc2.Des();
<a name="l00111"></a>00111
<a name="l00112"></a>00112 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KTxtTBufC);
<a name="l00113"></a>00113 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KCommonFormat6,
<a name="l00114"></a>00114 &bufc2,
<a name="l00115"></a>00115 bufc2.Ptr(),
<a name="l00116"></a>00116 bufc2.Length(),
<a name="l00117"></a>00117 bufc2.Size()
<a name="l00118"></a>00118 );
<a name="l00119"></a>00119
<a name="l00120"></a>00120 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KTxtTPtr);
<a name="l00121"></a>00121 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KCommonFormat7,
<a name="l00122"></a>00122 &ptr,
<a name="l00123"></a>00123 ptr.Ptr(),
<a name="l00124"></a>00124 ptr.Length(),
<a name="l00125"></a>00125 ptr.Size()
<a name="l00126"></a>00126 );
<a name="l00127"></a>00127
<a name="l00128"></a>00128 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KCommonFormat8,ptr.MaxLength());
<a name="l00129"></a>00129
<a name="l00130"></a>00130 <span class="comment">// Now change the TBufC data through</span>
<a name="l00131"></a>00131 <span class="comment">// the TPtr. This is OK provided the length</span>
<a name="l00132"></a>00132 <span class="comment">// of the changed data does not exceed 16.</span>
<a name="l00133"></a>00133 <span class="comment">//</span>
<a name="l00134"></a>00134 <span class="comment">// The following change deletes the last </span>
<a name="l00135"></a>00135 <span class="comment">// character (the "!") and appends </span>
<a name="l00136"></a>00136 <span class="comment">// the characters " & Hi".</span>
<a name="l00137"></a>00137 <span class="comment">//</span>
<a name="l00138"></a>00138 <span class="comment">// Note that the length of both the TBufC </span>
<a name="l00139"></a>00139 <span class="comment">// and the TPtr reflect the changed data.</span>
<a name="l00140"></a>00140 _LIT(KTxtAndHi,<span class="stringliteral">" & Hi"</span>);
<a name="l00141"></a>00141 ptr.Delete((ptr.Length()-1),1);
<a name="l00142"></a>00142 ptr.Append(KTxtAndHi);
<a name="l00143"></a>00143
<a name="l00144"></a>00144 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KTxtTBufC);
<a name="l00145"></a>00145 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KCommonFormat6,
<a name="l00146"></a>00146 &bufc2,
<a name="l00147"></a>00147 bufc2.Ptr(),
<a name="l00148"></a>00148 bufc2.Length(),
<a name="l00149"></a>00149 bufc2.Size()
<a name="l00150"></a>00150 );
<a name="l00151"></a>00151
<a name="l00152"></a>00152 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KTxtTPtr);
<a name="l00153"></a>00153 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KCommonFormat7,
<a name="l00154"></a>00154 &ptr,
<a name="l00155"></a>00155 ptr.Ptr(),
<a name="l00156"></a>00156 ptr.Length(),
<a name="l00157"></a>00157 ptr.Size()
<a name="l00158"></a>00158 );
<a name="l00159"></a>00159 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KCommonFormat8,ptr.MaxLength());
<a name="l00160"></a>00160
<a name="l00161"></a>00161 <span class="comment">// * * * * * * * * * * * * * * * * * * * * * * * * * * * *</span>
<a name="l00162"></a>00162 <span class="comment">// * * * * * * * * * * * * * * * * * * * * * * * * * * * *</span>
<a name="l00163"></a>00163
<a name="l00164"></a>00164 _LIT(KTxtBasicConcepts,<span class="stringliteral">"\n-->TBuf basic concepts"</span>);
<a name="l00165"></a>00165 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KTxtBasicConcepts);
<a name="l00166"></a>00166 _LIT(KTxtPressToContinue,<span class="stringliteral">" (press any key to continue)\n"</span>);
<a name="l00167"></a>00167 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KTxtPressToContinue);
<a name="l00168"></a>00168 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Getch();
<a name="l00169"></a>00169
<a name="l00170"></a>00170 <span class="comment">// Construct a TBuf using a Literal </span>
<a name="l00171"></a>00171 TBuf<16> buf(KTxtHelloWorld);
<a name="l00172"></a>00172
<a name="l00173"></a>00173 <span class="comment">// Look at: </span>
<a name="l00174"></a>00174 <span class="comment">// 1. Descriptor content</span>
<a name="l00175"></a>00175 <span class="comment">// 2. Address of descriptor</span>
<a name="l00176"></a>00176 <span class="comment">// 3. Address of descriptor data area</span>
<a name="l00177"></a>00177 <span class="comment">// 4. Length of descriptor</span>
<a name="l00178"></a>00178 <span class="comment">// 5. Size of descriptor</span>
<a name="l00179"></a>00179 <span class="comment">// 6. Maximum length of descriptor </span>
<a name="l00180"></a>00180 <span class="comment">//</span>
<a name="l00181"></a>00181 <span class="comment">// Like a TBufC, the address of the descriptor</span>
<a name="l00182"></a>00182 <span class="comment">// data area is offset 4 from the start of the</span>
<a name="l00183"></a>00183 <span class="comment">// descriptor itself.</span>
<a name="l00184"></a>00184 <span class="comment">//</span>
<a name="l00185"></a>00185 <span class="comment">// Descriptor length is 12.</span>
<a name="l00186"></a>00186 <span class="comment">//</span>
<a name="l00187"></a>00187 <span class="comment">// The template parameter value defines </span>
<a name="l00188"></a>00188 <span class="comment">// the maximum length of the descriptor. </span>
<a name="l00189"></a>00189 <span class="comment">// and, therefore, governs its size </span>
<a name="l00190"></a>00190 <span class="comment">// (depending on the build variant).</span>
<a name="l00191"></a>00191 <span class="comment">// Size of data is 24</span>
<a name="l00192"></a>00192
<a name="l00193"></a>00193 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KCommonFormat2,&buf);
<a name="l00194"></a>00194 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KCommonFormat3,&buf,buf.Ptr());
<a name="l00195"></a>00195 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KCommonFormat9,buf.Length(),buf.Size());
<a name="l00196"></a>00196 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KCommonFormat10,buf.MaxLength());
<a name="l00197"></a>00197
<a name="l00198"></a>00198 <span class="comment">// The data can be modified</span>
<a name="l00199"></a>00199 buf.Append(<span class="charliteral">'@'</span>);
<a name="l00200"></a>00200 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KCommonFormat2,&buf);
<a name="l00201"></a>00201 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KCommonFormat9,buf.Length(),buf.Size());
<a name="l00202"></a>00202 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KCommonFormat10,buf.MaxLength());
<a name="l00203"></a>00203
<a name="l00204"></a>00204 <span class="comment">// Length can be changed; data represented</span>
<a name="l00205"></a>00205 <span class="comment">// by the descriptor is now "Hel"</span>
<a name="l00206"></a>00206 buf.SetLength(3);
<a name="l00207"></a>00207 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KCommonFormat2,&buf);
<a name="l00208"></a>00208 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KCommonFormat9,buf.Length(),buf.Size());
<a name="l00209"></a>00209 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KCommonFormat10,buf.MaxLength());
<a name="l00210"></a>00210
<a name="l00211"></a>00211 <span class="comment">// Length can be zeroised; no data is now </span>
<a name="l00212"></a>00212 <span class="comment">// represented by the descriptor but </span>
<a name="l00213"></a>00213 <span class="comment">// the maximum length is still 16</span>
<a name="l00214"></a>00214 buf.Zero();
<a name="l00215"></a>00215 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KCommonFormat2,&buf);
<a name="l00216"></a>00216 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KCommonFormat9,buf.Length(),buf.Size());
<a name="l00217"></a>00217 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KCommonFormat10,buf.MaxLength());
<a name="l00218"></a>00218
<a name="l00219"></a>00219 <span class="comment">// The data can be replaced entirely </span>
<a name="l00220"></a>00220 <span class="comment">// using the assignment operator.</span>
<a name="l00221"></a>00221 <span class="comment">// The replacement text must not have a</span>
<a name="l00222"></a>00222 <span class="comment">// length greater than 16.</span>
<a name="l00223"></a>00223 buf = KTxtRepText;
<a name="l00224"></a>00224 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KCommonFormat2,&buf);
<a name="l00225"></a>00225 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KCommonFormat9,buf.Length(),buf.Size());
<a name="l00226"></a>00226 <a class="code" href="dbllist_8cpp.html#d789d40251baeb2f60e118de4856583d">console</a>->Printf(KCommonFormat10,buf.MaxLength());
<a name="l00227"></a>00227
<a name="l00228"></a>00228 <span class="comment">// Replacing text which has a length > 16</span>
<a name="l00229"></a>00229 <span class="comment">// causes panic !!</span>
<a name="l00230"></a>00230 <span class="comment">// </span>
<a name="l00231"></a>00231 <span class="comment">// Remove the "//" marks on the next two lines</span>
<a name="l00232"></a>00232 <span class="comment">// to see this happen</span>
<a name="l00233"></a>00233 <span class="comment">//_LIT(KTxtRepTextPanic,"Text replacement causes panic");</span>
<a name="l00234"></a>00234 <span class="comment">//buf = _L("Text replacement causes panic!");</span>
<a name="l00235"></a>00235 }
<a name="l00236"></a>00236
<a name="l00237"></a>00237
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</pre></div><hr size="1"><address style="text-align: right;"><small>Generated on Thu Jan 21 10:32:55 2010 for TB10.1 Example Applications by
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