waitconditions.cpp Example File

 /****************************************************************************
 **
 ** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
 ** All rights reserved.
 ** Contact: Nokia Corporation (qt-info@nokia.com)
 **
 ** This file is part of the examples of the Qt Toolkit.
 **
 ** $QT_BEGIN_LICENSE:BSD$
 ** You may use this file under the terms of the BSD license as follows:
 **
 ** "Redistribution and use in source and binary forms, with or without
 ** modification, are permitted provided that the following conditions are
 ** met:
 **   * Redistributions of source code must retain the above copyright
 **     notice, this list of conditions and the following disclaimer.
 **   * Redistributions in binary form must reproduce the above copyright
 **     notice, this list of conditions and the following disclaimer in
 **     the documentation and/or other materials provided with the
 **     distribution.
 **   * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
 **     the names of its contributors may be used to endorse or promote
 **     products derived from this software without specific prior written
 **     permission.
 **
 ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/

 #include <QtGui>

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

 #ifdef Q_WS_S60
 const int DataSize = 300;
 #else
 const int DataSize = 100000;
 #endif

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

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

 class Producer : public QThread
 {
 public:
     Producer(QObject *parent = NULL) : QThread(parent)
     {
     }

     void 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
 {
     Q_OBJECT
 public:
     Consumer(QObject *parent = NULL) : QThread(parent)
     {
     }

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

     #ifdef Q_WS_S60
             emit stringConsumed(QString(buffer[i % BufferSize]));
     #else
             fprintf(stderr, "%c", buffer[i % BufferSize]);
     #endif

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

 signals:
     void stringConsumed(const QString &text);
 };

 #ifdef Q_WS_S60
 class PlainTextEdit : public QPlainTextEdit
 {
     Q_OBJECT
 public:
     PlainTextEdit(QWidget *parent = NULL) : QPlainTextEdit(parent), producer(NULL), consumer(NULL)
     {
         setTextInteractionFlags(Qt::NoTextInteraction);

         producer = new Producer(this);
         consumer = new Consumer(this);

         QObject::connect(consumer, SIGNAL(stringConsumed(const QString &)), SLOT(insertPlainText(const QString &)), Qt::BlockingQueuedConnection);

         QTimer::singleShot(0, this, SLOT(startThreads()));
     }

 protected:
     Producer *producer;
     Consumer *consumer;

 protected slots:
     void startThreads()
     {
         producer->start();
         consumer->start();
     }
 };
 #endif

 int main(int argc, char *argv[])
 {
 #ifdef Q_WS_S60
     QApplication app(argc, argv);

     PlainTextEdit console;
     console.showMaximized();

     return app.exec();
 #else
     QCoreApplication app(argc, argv);
     Producer producer;
     Consumer consumer;
     producer.start();
     consumer.start();
     producer.wait();
     consumer.wait();
     return 0;
 #endif
 }

 #include "waitconditions.moc"