waitconditions.cpp Example File

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 #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"