semaphores.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];

 QSemaphore freeBytes(BufferSize);
 QSemaphore usedBytes;

 class Producer : public QThread
 {
 public:
     void run()
     {
         qsrand(QTime(0,0,0).secsTo(QTime::currentTime()));
         for (int i = 0; i < DataSize; ++i) {
             freeBytes.acquire();
             buffer[i % BufferSize] = "ACGT"[(int)qrand() % 4];
             usedBytes.release();
         }
     }
 };

 class Consumer : public QThread
 {
     Q_OBJECT
 public:
     void run()
     {
         for (int i = 0; i < DataSize; ++i) {
             usedBytes.acquire();
     #ifdef Q_WS_S60
             QString text(buffer[i % BufferSize]);
             freeBytes.release();
             emit stringConsumed(text);
     #else
             fprintf(stderr, "%c", buffer[i % BufferSize]);
             freeBytes.release();
     #endif
         }
         fprintf(stderr, "\n");
     }

 signals:
     void stringConsumed(const QString &text);

 protected:
     bool finish;
 };

 int main(int argc, char *argv[])
 {
 #ifdef Q_WS_S60
     // Self made console for Symbian
     QApplication app(argc, argv);
     QPlainTextEdit console;
     console.setReadOnly(true);
     console.setTextInteractionFlags(Qt::NoTextInteraction);
     console.showMaximized();

     Producer producer;
     Consumer consumer;

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

     producer.start();
     consumer.start();

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

 #include "semaphores.moc"