Home · All Classes · Main Classes · Grouped Classes · Modules · Functions

waitconditions.cpp Example File
^{threads/waitconditions/waitconditions.cpp}

 /****************************************************************************
 **
 ** Copyright (C) 2005-2007 Trolltech ASA. All rights reserved.
 **
 ** This file is part of the example classes of the Qt Toolkit.
 **
 ** This file may be used under the terms of the GNU General Public
 ** License version 2.0 as published by the Free Software Foundation
 ** and appearing in the file LICENSE.GPL included in the packaging of
 ** this file.  Please review the following information to ensure GNU
 ** General Public Licensing requirements will be met:
 ** http://www.trolltech.com/products/qt/opensource.html
 **
 ** If you are unsure which license is appropriate for your use, please
 ** review the following information:
 ** http://www.trolltech.com/products/qt/licensing.html or contact the
 ** sales department at [email protected].
 **
 ** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
 ** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 **
 ****************************************************************************/

 #include <QtCore>

 #include <stdio.h>
 #include <stdlib.h>

 const int DataSize = 100000;
 const int BufferSize = 8192;
 char buffer[BufferSize];

 QWaitCondition bufferNotEmpty;
 QWaitCondition bufferNotFull;
 QMutex mutex;
 int numUsedBytes = 0;

 class Producer : public QThread
 {
 public:
     void run();
 };

 void Producer::run()
 {
     qsrand(QTime(0,0,0).secsTo(QTime::currentTime()));

     for (int i = 0; i < DataSize; ++i) {
         mutex.lock();
         if (numUsedBytes == BufferSize)
             bufferNotFull.wait(&mutex);
         mutex.unlock();

         buffer[i % BufferSize] = "ACGT"[(int)qrand() % 4];

         mutex.lock();
         ++numUsedBytes;
         bufferNotEmpty.wakeAll();
         mutex.unlock();
     }
 }

 class Consumer : public QThread
 {
 public:
     void run();
 };

 void Consumer::run()
 {
     for (int i = 0; i < DataSize; ++i) {
         mutex.lock();
         if (numUsedBytes == 0)
             bufferNotEmpty.wait(&mutex);
         mutex.unlock();

         fprintf(stderr, "%c", buffer[i % BufferSize]);

         mutex.lock();
         --numUsedBytes;
         bufferNotFull.wakeAll();
         mutex.unlock();
     }
     fprintf(stderr, "\n");
 }

 int main(int argc, char *argv[])
 {
     QCoreApplication app(argc, argv);
     Producer producer;
     Consumer consumer;
     producer.start();
     consumer.start();
     producer.wait();
     consumer.wait();
     return 0;
 }