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<h1>dataqueue.cc</h1><a href="dataqueue_8cc.html">Go to the documentation of this file.</a><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">///</span>
<a name="l00002"></a>00002 <span class="comment"></span><span class="comment">/// \file dataqueue.cc</span>
<a name="l00003"></a>00003 <span class="comment"></span><span class="comment">/// FIFO queue of Data objects</span>
<a name="l00004"></a>00004 <span class="comment"></span><span class="comment">///</span>
<a name="l00005"></a>00005 <span class="comment"></span>
<a name="l00006"></a>00006 <span class="comment">/*</span>
<a name="l00007"></a>00007 <span class="comment"> Copyright (C) 2008-2010, Net Direct Inc. (http://www.netdirect.ca/)</span>
<a name="l00008"></a>00008 <span class="comment"></span>
<a name="l00009"></a>00009 <span class="comment"> This program is free software; you can redistribute it and/or modify</span>
<a name="l00010"></a>00010 <span class="comment"> it under the terms of the GNU General Public License as published by</span>
<a name="l00011"></a>00011 <span class="comment"> the Free Software Foundation; either version 2 of the License, or</span>
<a name="l00012"></a>00012 <span class="comment"> (at your option) any later version.</span>
<a name="l00013"></a>00013 <span class="comment"></span>
<a name="l00014"></a>00014 <span class="comment"> This program is distributed in the hope that it will be useful,</span>
<a name="l00015"></a>00015 <span class="comment"> but WITHOUT ANY WARRANTY; without even the implied warranty of</span>
<a name="l00016"></a>00016 <span class="comment"> MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.</span>
<a name="l00017"></a>00017 <span class="comment"></span>
<a name="l00018"></a>00018 <span class="comment"> See the GNU General Public License in the COPYING file at the</span>
<a name="l00019"></a>00019 <span class="comment"> root directory of this project for more details.</span>
<a name="l00020"></a>00020 <span class="comment">*/</span>
<a name="l00021"></a>00021
<a name="l00022"></a>00022 <span class="preprocessor">#include "<a class="code" href="dataqueue_8h.html" title="FIFO queue of Data objects.">dataqueue.h</a>"</span>
<a name="l00023"></a>00023 <span class="preprocessor">#include "<a class="code" href="scoped__lock_8h.html" title="Simple scope class for dealing with pthread mutex locking.">scoped_lock.h</a>"</span>
<a name="l00024"></a>00024 <span class="preprocessor">#include "<a class="code" href="data_8h.html" title="Class to deal with pre-saved data files.">data.h</a>"</span>
<a name="l00025"></a>00025 <span class="preprocessor">#include "<a class="code" href="time_8h.html" title="Time related conversion routines.">time.h</a>"</span>
<a name="l00026"></a>00026
<a name="l00027"></a>00027 <span class="keyword">namespace </span>Barry {
<a name="l00028"></a>00028 <span class="comment"></span>
<a name="l00029"></a>00029 <span class="comment">//////////////////////////////////////////////////////////////////////////////</span>
<a name="l00030"></a>00030 <span class="comment"></span><span class="comment">// DataQueue class</span>
<a name="l00031"></a>00031
<a name="l00032"></a>00032 DataQueue::DataQueue()
<a name="l00033"></a>00033 {
<a name="l00034"></a>00034 pthread_mutex_init(&m_waitMutex, NULL);
<a name="l00035"></a>00035 pthread_cond_init(&m_waitCond, NULL);
<a name="l00036"></a>00036
<a name="l00037"></a>00037 pthread_mutex_init(&m_accessMutex, NULL);
<a name="l00038"></a>00038 }
<a name="l00039"></a>00039
<a name="l00040"></a>00040 DataQueue::~DataQueue()
<a name="l00041"></a>00041 {
<a name="l00042"></a>00042 scoped_lock lock(m_accessMutex); <span class="comment">// FIXME - is this sane?</span>
<a name="l00043"></a>00043
<a name="l00044"></a>00044 <span class="keywordflow">while</span>( m_queue.size() ) {
<a name="l00045"></a>00045 <span class="keyword">delete</span> m_queue.front();
<a name="l00046"></a>00046 m_queue.pop();
<a name="l00047"></a>00047 }
<a name="l00048"></a>00048 }
<a name="l00049"></a>00049
<a name="l00050"></a>00050 <span class="comment">//</span>
<a name="l00051"></a>00051 <span class="comment">// push</span>
<a name="l00052"></a>00052 <span class="comment">//</span><span class="comment"></span>
<a name="l00053"></a>00053 <span class="comment">/// Pushes data into the end of the queue.</span>
<a name="l00054"></a>00054 <span class="comment">///</span>
<a name="l00055"></a>00055 <span class="comment">/// The queue owns this pointer as soon as the function is</span>
<a name="l00056"></a>00056 <span class="comment">/// called. In the case of an exception, it will be freed.</span>
<a name="l00057"></a>00057 <span class="comment">/// Performs a thread broadcast once new data has been added.</span>
<a name="l00058"></a><a class="code" href="classBarry_1_1DataQueue.html#aea470a11cbda20dd9af1a92148ecb223">00058</a> <span class="comment">///</span>
<a name="l00059"></a>00059 <span class="comment"></span><span class="keywordtype">void</span> <a class="code" href="classBarry_1_1DataQueue.html#aea470a11cbda20dd9af1a92148ecb223" title="Pushes data into the end of the queue.">DataQueue::push</a>(<a class="code" href="classBarry_1_1Data.html">Data</a> *data)
<a name="l00060"></a>00060 {
<a name="l00061"></a>00061 <span class="keywordflow">try</span> {
<a name="l00062"></a>00062
<a name="l00063"></a>00063 {
<a name="l00064"></a>00064 <a class="code" href="classBarry_1_1scoped__lock.html">scoped_lock</a> lock(m_accessMutex);
<a name="l00065"></a>00065 m_queue.push(data);
<a name="l00066"></a>00066 }
<a name="l00067"></a>00067
<a name="l00068"></a>00068 <a class="code" href="classBarry_1_1scoped__lock.html">scoped_lock</a> wait(m_waitMutex);
<a name="l00069"></a>00069 pthread_cond_broadcast(&m_waitCond);
<a name="l00070"></a>00070
<a name="l00071"></a>00071 }
<a name="l00072"></a>00072 <span class="keywordflow">catch</span>(...) {
<a name="l00073"></a>00073 <span class="keyword">delete</span> data;
<a name="l00074"></a>00074 <span class="keywordflow">throw</span>;
<a name="l00075"></a>00075 }
<a name="l00076"></a>00076 }
<a name="l00077"></a>00077
<a name="l00078"></a>00078 <span class="comment">//</span>
<a name="l00079"></a>00079 <span class="comment">// pop</span>
<a name="l00080"></a>00080 <span class="comment">//</span><span class="comment"></span>
<a name="l00081"></a>00081 <span class="comment">/// Pops the next element off the front of the queue.</span>
<a name="l00082"></a>00082 <span class="comment">///</span>
<a name="l00083"></a>00083 <span class="comment">/// Returns 0 if empty.</span>
<a name="l00084"></a>00084 <span class="comment">/// The queue no longer owns this pointer upon return.</span>
<a name="l00085"></a><a class="code" href="classBarry_1_1DataQueue.html#ad1f454f70a9b6ec667e0e22a7ddd6eca">00085</a> <span class="comment">///</span>
<a name="l00086"></a>00086 <span class="comment"></span><a class="code" href="classBarry_1_1Data.html">Data</a>* <a class="code" href="classBarry_1_1DataQueue.html#ad1f454f70a9b6ec667e0e22a7ddd6eca" title="Pops the next element off the front of the queue.">DataQueue::pop</a>()
<a name="l00087"></a>00087 {
<a name="l00088"></a>00088 <a class="code" href="classBarry_1_1scoped__lock.html">scoped_lock</a> lock(m_accessMutex);
<a name="l00089"></a>00089
<a name="l00090"></a>00090 <span class="keywordflow">if</span>( m_queue.size() == 0 )
<a name="l00091"></a>00091 <span class="keywordflow">return</span> 0;
<a name="l00092"></a>00092
<a name="l00093"></a>00093 <a class="code" href="classBarry_1_1Data.html">Data</a> *ret = m_queue.front();
<a name="l00094"></a>00094 m_queue.pop();
<a name="l00095"></a>00095 <span class="keywordflow">return</span> ret;
<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">// wait_pop</span>
<a name="l00100"></a>00100 <span class="comment">//</span><span class="comment"></span>
<a name="l00101"></a>00101 <span class="comment">/// Pops the next element off the front of the queue, and</span>
<a name="l00102"></a>00102 <span class="comment">/// waits until one exists if empty. If still no data</span>
<a name="l00103"></a>00103 <span class="comment">/// on timeout, returns null.</span>
<a name="l00104"></a>00104 <span class="comment">/// (unlock the access mutex while waiting!)</span>
<a name="l00105"></a>00105 <span class="comment">///</span>
<a name="l00106"></a>00106 <span class="comment">/// Timeout specified in milliseconds. Default is wait forever.</span>
<a name="l00107"></a><a class="code" href="classBarry_1_1DataQueue.html#a27d4830d37b0f7a1bee3a63b0f5a5b2b">00107</a> <span class="comment">///</span>
<a name="l00108"></a>00108 <span class="comment"></span><a class="code" href="classBarry_1_1Data.html">Data</a>* <a class="code" href="classBarry_1_1DataQueue.html#a27d4830d37b0f7a1bee3a63b0f5a5b2b" title="Pops the next element off the front of the queue, and waits until one exists if empty...">DataQueue::wait_pop</a>(<span class="keywordtype">int</span> timeout)
<a name="l00109"></a>00109 {
<a name="l00110"></a>00110 <a class="code" href="classBarry_1_1Data.html">Data</a> *ret = 0;
<a name="l00111"></a>00111
<a name="l00112"></a>00112 <span class="comment">// check if something's there already</span>
<a name="l00113"></a>00113 {
<a name="l00114"></a>00114 <a class="code" href="classBarry_1_1scoped__lock.html">scoped_lock</a> access(m_accessMutex);
<a name="l00115"></a>00115 <span class="keywordflow">if</span>( m_queue.size() ) {
<a name="l00116"></a>00116 ret = m_queue.front();
<a name="l00117"></a>00117 m_queue.pop();
<a name="l00118"></a>00118 <span class="keywordflow">return</span> ret;
<a name="l00119"></a>00119 }
<a name="l00120"></a>00120 }
<a name="l00121"></a>00121
<a name="l00122"></a>00122 <span class="comment">// nothing there, so wait...</span>
<a name="l00123"></a>00123
<a name="l00124"></a>00124 <span class="keywordflow">if</span>( timeout == -1 ) {
<a name="l00125"></a>00125 <span class="comment">// no timeout</span>
<a name="l00126"></a>00126 <span class="keywordtype">int</span> <a class="code" href="classBarry_1_1DataQueue.html#ada0c2fd55a8f221aadbf0b7165043e06" title="Returns number of items in the queue.">size</a> = 0;
<a name="l00127"></a>00127 <span class="keywordflow">do</span> {
<a name="l00128"></a>00128 {
<a name="l00129"></a>00129 <a class="code" href="classBarry_1_1scoped__lock.html">scoped_lock</a> wait(m_waitMutex);
<a name="l00130"></a>00130 pthread_cond_wait(&m_waitCond, &m_waitMutex);
<a name="l00131"></a>00131 }
<a name="l00132"></a>00132
<a name="l00133"></a>00133 <span class="comment">// anything there?</span>
<a name="l00134"></a>00134 <a class="code" href="classBarry_1_1scoped__lock.html">scoped_lock</a> access(m_accessMutex);
<a name="l00135"></a>00135 size = m_queue.size();
<a name="l00136"></a>00136 <span class="keywordflow">if</span>( size != 0 ) {
<a name="l00137"></a>00137 <span class="comment">// already have the lock, return now</span>
<a name="l00138"></a>00138 ret = m_queue.front();
<a name="l00139"></a>00139 m_queue.pop();
<a name="l00140"></a>00140 <span class="keywordflow">return</span> ret;
<a name="l00141"></a>00141 }
<a name="l00142"></a>00142
<a name="l00143"></a>00143 } <span class="keywordflow">while</span>( size == 0 );
<a name="l00144"></a>00144 }
<a name="l00145"></a>00145 <span class="keywordflow">else</span> {
<a name="l00146"></a>00146 <span class="comment">// timeout in conditional wait</span>
<a name="l00147"></a>00147 <span class="keyword">struct </span>timespec to;
<a name="l00148"></a>00148 <a class="code" href="classBarry_1_1scoped__lock.html">scoped_lock</a> wait(m_waitMutex);
<a name="l00149"></a>00149 pthread_cond_timedwait(&m_waitCond, &m_waitMutex,
<a name="l00150"></a>00150 <a class="code" href="namespaceBarry.html#a0e1dc80f82d25739631c39b545f812bb" title="Creates a pthread_cond_timedwait() compatible timespec struct, based on a given timeout...">ThreadTimeout</a>(timeout, &to));
<a name="l00151"></a>00151 }
<a name="l00152"></a>00152
<a name="l00153"></a>00153 <a class="code" href="classBarry_1_1scoped__lock.html">scoped_lock</a> access(m_accessMutex);
<a name="l00154"></a>00154 <span class="keywordflow">if</span>( m_queue.size() == 0 )
<a name="l00155"></a>00155 <span class="keywordflow">return</span> 0;
<a name="l00156"></a>00156
<a name="l00157"></a>00157 ret = m_queue.front();
<a name="l00158"></a>00158 m_queue.pop();
<a name="l00159"></a>00159 <span class="keywordflow">return</span> ret;
<a name="l00160"></a>00160 }
<a name="l00161"></a>00161
<a name="l00162"></a>00162 <span class="comment">//</span>
<a name="l00163"></a>00163 <span class="comment">// append_from</span>
<a name="l00164"></a>00164 <span class="comment">//</span><span class="comment"></span>
<a name="l00165"></a>00165 <span class="comment">/// Pops all data from other and appends it to this.</span>
<a name="l00166"></a>00166 <span class="comment">///</span>
<a name="l00167"></a>00167 <span class="comment">/// After calling this function, other will be empty, and</span>
<a name="l00168"></a>00168 <span class="comment">/// this will contain all its data.</span>
<a name="l00169"></a>00169 <span class="comment">///</span>
<a name="l00170"></a>00170 <span class="comment">/// In the case of an exception, any uncopied data will</span>
<a name="l00171"></a>00171 <span class="comment">/// remain in other.</span>
<a name="l00172"></a>00172 <span class="comment">///</span>
<a name="l00173"></a>00173 <span class="comment">/// This is a locking optimization, so all copying can happen</span>
<a name="l00174"></a>00174 <span class="comment">/// inside one lock, instead of locking for each copy.</span>
<a name="l00175"></a><a class="code" href="classBarry_1_1DataQueue.html#a12a7a82124799a6803b28efd89e1dd05">00175</a> <span class="comment">///</span>
<a name="l00176"></a>00176 <span class="comment"></span><span class="keywordtype">void</span> <a class="code" href="classBarry_1_1DataQueue.html#a12a7a82124799a6803b28efd89e1dd05" title="Pops all data from other and appends it to this.">DataQueue::append_from</a>(<a class="code" href="classBarry_1_1DataQueue.html" title="This class provides a thread aware fifo queue for Data objects, providing memory...">DataQueue</a> &other)
<a name="l00177"></a>00177 {
<a name="l00178"></a>00178 <a class="code" href="classBarry_1_1scoped__lock.html">scoped_lock</a> us(m_accessMutex);
<a name="l00179"></a>00179 <a class="code" href="classBarry_1_1scoped__lock.html">scoped_lock</a> them(other.m_accessMutex);
<a name="l00180"></a>00180
<a name="l00181"></a>00181 <span class="keywordflow">while</span>( other.m_queue.size() ) {
<a name="l00182"></a>00182 m_queue.push( other.m_queue.front() );
<a name="l00183"></a>00183
<a name="l00184"></a>00184 <span class="comment">// only pop after the copy, since in the</span>
<a name="l00185"></a>00185 <span class="comment">// case of an exception we want to leave other intact</span>
<a name="l00186"></a>00186 other.m_queue.pop();
<a name="l00187"></a>00187 }
<a name="l00188"></a>00188 }
<a name="l00189"></a>00189
<a name="l00190"></a>00190 <span class="comment">//</span>
<a name="l00191"></a>00191 <span class="comment">// empty</span>
<a name="l00192"></a>00192 <span class="comment">//</span><span class="comment"></span>
<a name="l00193"></a>00193 <span class="comment">/// Returns true if the queue is empty.</span>
<a name="l00194"></a><a class="code" href="classBarry_1_1DataQueue.html#a76cecba41e423f7d20df464cf7524e76">00194</a> <span class="comment">///</span>
<a name="l00195"></a>00195 <span class="comment"></span><span class="keywordtype">bool</span> <a class="code" href="classBarry_1_1DataQueue.html#a76cecba41e423f7d20df464cf7524e76" title="Returns true if the queue is empty.">DataQueue::empty</a>()<span class="keyword"> const</span>
<a name="l00196"></a>00196 <span class="keyword"></span>{
<a name="l00197"></a>00197 <a class="code" href="classBarry_1_1scoped__lock.html">scoped_lock</a> access(m_accessMutex);
<a name="l00198"></a>00198 <span class="keywordflow">return</span> m_queue.size() == 0;
<a name="l00199"></a>00199 }
<a name="l00200"></a>00200
<a name="l00201"></a>00201 <span class="comment">//</span>
<a name="l00202"></a>00202 <span class="comment">// size</span>
<a name="l00203"></a>00203 <span class="comment">//</span><span class="comment"></span>
<a name="l00204"></a>00204 <span class="comment">/// Returns number of items in the queue.</span>
<a name="l00205"></a><a class="code" href="classBarry_1_1DataQueue.html#ada0c2fd55a8f221aadbf0b7165043e06">00205</a> <span class="comment">///</span>
<a name="l00206"></a>00206 <span class="comment"></span><span class="keywordtype">size_t</span> <a class="code" href="classBarry_1_1DataQueue.html#ada0c2fd55a8f221aadbf0b7165043e06" title="Returns number of items in the queue.">DataQueue::size</a>()<span class="keyword"> const</span>
<a name="l00207"></a>00207 <span class="keyword"></span>{
<a name="l00208"></a>00208 <a class="code" href="classBarry_1_1scoped__lock.html">scoped_lock</a> access(m_accessMutex);
<a name="l00209"></a>00209 <span class="keywordflow">return</span> m_queue.size();
<a name="l00210"></a>00210 }
<a name="l00211"></a>00211
<a name="l00212"></a>00212 } <span class="comment">// namespace Barry</span>
<a name="l00213"></a>00213
<a name="l00214"></a>00214
<a name="l00215"></a>00215 <span class="preprocessor">#ifdef __DQ_TEST_MODE__</span>
<a name="l00216"></a>00216 <span class="preprocessor"></span>
<a name="l00217"></a>00217 <span class="preprocessor">#include <iostream></span>
<a name="l00218"></a>00218
<a name="l00219"></a>00219 <span class="keyword">using namespace </span>std;
<a name="l00220"></a>00220 <span class="keyword">using namespace </span>Barry;
<a name="l00221"></a>00221
<a name="l00222"></a>00222 <span class="keywordtype">void</span> *WriteThread(<span class="keywordtype">void</span> *userdata)
<a name="l00223"></a>00223 {
<a name="l00224"></a>00224 DataQueue *dq = (DataQueue*) userdata;
<a name="l00225"></a>00225
<a name="l00226"></a>00226 dq->push( <span class="keyword">new</span> Data );
<a name="l00227"></a>00227 dq->push( <span class="keyword">new</span> Data );
<a name="l00228"></a>00228 sleep(5);
<a name="l00229"></a>00229 dq->push( <span class="keyword">new</span> Data );
<a name="l00230"></a>00230
<a name="l00231"></a>00231 <span class="keywordflow">return</span> 0;
<a name="l00232"></a>00232 }
<a name="l00233"></a>00233
<a name="l00234"></a>00234 <span class="keywordtype">void</span> *ReadThread(<span class="keywordtype">void</span> *userdata)
<a name="l00235"></a>00235 {
<a name="l00236"></a>00236 DataQueue *dq = (DataQueue*) userdata;
<a name="l00237"></a>00237
<a name="l00238"></a>00238 sleep(1);
<a name="l00239"></a>00239 <span class="keywordflow">if</span>( Data *d = dq->pop() ) {
<a name="l00240"></a>00240 cout << <span class="stringliteral">"Received via pop: "</span> << d << endl;
<a name="l00241"></a>00241 <span class="keyword">delete</span> d;
<a name="l00242"></a>00242 }
<a name="l00243"></a>00243 <span class="keywordflow">else</span> {
<a name="l00244"></a>00244 cout << <span class="stringliteral">"No data in the queue yet."</span> << endl;
<a name="l00245"></a>00245 }
<a name="l00246"></a>00246
<a name="l00247"></a>00247 <span class="keywordflow">while</span>( Data *d = dq->wait_pop(5010) ) {
<a name="l00248"></a>00248 cout << <span class="stringliteral">"Received: "</span> << d << endl;
<a name="l00249"></a>00249 <span class="keyword">delete</span> d;
<a name="l00250"></a>00250 }
<a name="l00251"></a>00251 <span class="keywordflow">return</span> 0;
<a name="l00252"></a>00252 }
<a name="l00253"></a>00253
<a name="l00254"></a>00254 <span class="keywordtype">int</span> main()
<a name="l00255"></a>00255 {
<a name="l00256"></a>00256 DataQueue from;
<a name="l00257"></a>00257 from.push( <span class="keyword">new</span> Data );
<a name="l00258"></a>00258
<a name="l00259"></a>00259 DataQueue dq;
<a name="l00260"></a>00260 dq.append_from(from);
<a name="l00261"></a>00261
<a name="l00262"></a>00262 pthread_t t1, t2;
<a name="l00263"></a>00263 pthread_create(&t1, NULL, &ReadThread, &dq);
<a name="l00264"></a>00264 pthread_create(&t2, NULL, &WriteThread, &dq);
<a name="l00265"></a>00265
<a name="l00266"></a>00266 pthread_join(t2, NULL);
<a name="l00267"></a>00267 pthread_join(t1, NULL);
<a name="l00268"></a>00268 }
<a name="l00269"></a>00269
<a name="l00270"></a>00270 <span class="preprocessor">#endif</span>
<a name="l00271"></a>00271 <span class="preprocessor"></span>
</pre></div></div>
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