examples/threads/semaphores/semaphores.cpp
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     1 /****************************************************************************
       
     2 **
       
     3 ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
       
     4 ** All rights reserved.
       
     5 ** Contact: Nokia Corporation (qt-info@nokia.com)
       
     6 **
       
     7 ** This file is part of the examples of the Qt Toolkit.
       
     8 **
       
     9 ** $QT_BEGIN_LICENSE:LGPL$
       
    10 ** No Commercial Usage
       
    11 ** This file contains pre-release code and may not be distributed.
       
    12 ** You may use this file in accordance with the terms and conditions
       
    13 ** contained in the Technology Preview License Agreement accompanying
       
    14 ** this package.
       
    15 **
       
    16 ** GNU Lesser General Public License Usage
       
    17 ** Alternatively, this file may be used under the terms of the GNU Lesser
       
    18 ** General Public License version 2.1 as published by the Free Software
       
    19 ** Foundation and appearing in the file LICENSE.LGPL included in the
       
    20 ** packaging of this file.  Please review the following information to
       
    21 ** ensure the GNU Lesser General Public License version 2.1 requirements
       
    22 ** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
       
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    24 ** In addition, as a special exception, Nokia gives you certain additional
       
    25 ** rights.  These rights are described in the Nokia Qt LGPL Exception
       
    26 ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
       
    27 **
       
    28 ** If you have questions regarding the use of this file, please contact
       
    29 ** Nokia at qt-info@nokia.com.
       
    30 **
       
    31 **
       
    32 **
       
    33 **
       
    34 **
       
    35 **
       
    36 **
       
    37 **
       
    38 ** $QT_END_LICENSE$
       
    39 **
       
    40 ****************************************************************************/
       
    41 
       
    42 #include <QtCore>
       
    43 
       
    44 #include <stdio.h>
       
    45 #include <stdlib.h>
       
    46 
       
    47 //! [0]
       
    48 const int DataSize = 100000;
       
    49 const int BufferSize = 8192;
       
    50 char buffer[BufferSize];
       
    51 
       
    52 QSemaphore freeBytes(BufferSize);
       
    53 QSemaphore usedBytes;
       
    54 //! [0]
       
    55 
       
    56 //! [1]
       
    57 class Producer : public QThread
       
    58 //! [1] //! [2]
       
    59 {
       
    60 public:
       
    61     void run();
       
    62 };
       
    63 
       
    64 void Producer::run()
       
    65 {
       
    66     qsrand(QTime(0,0,0).secsTo(QTime::currentTime()));
       
    67     for (int i = 0; i < DataSize; ++i) {
       
    68         freeBytes.acquire();
       
    69         buffer[i % BufferSize] = "ACGT"[(int)qrand() % 4];
       
    70         usedBytes.release();
       
    71     }
       
    72 }
       
    73 //! [2]
       
    74 
       
    75 //! [3]
       
    76 class Consumer : public QThread
       
    77 //! [3] //! [4]
       
    78 {
       
    79 public:
       
    80     void run();
       
    81 };
       
    82 
       
    83 void Consumer::run()
       
    84 {
       
    85     for (int i = 0; i < DataSize; ++i) {
       
    86         usedBytes.acquire();
       
    87         fprintf(stderr, "%c", buffer[i % BufferSize]);
       
    88         freeBytes.release();
       
    89     }
       
    90     fprintf(stderr, "\n");
       
    91 }
       
    92 //! [4]
       
    93 
       
    94 //! [5]
       
    95 int main(int argc, char *argv[])
       
    96 //! [5] //! [6]
       
    97 {
       
    98     QCoreApplication app(argc, argv);
       
    99     Producer producer;
       
   100     Consumer consumer;
       
   101     producer.start();
       
   102     consumer.start();
       
   103     producer.wait();
       
   104     consumer.wait();
       
   105     return 0;
       
   106 }
       
   107 //! [6]