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+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Qt Software Information (qt-info@nokia.com)
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the either Technology Preview License Agreement or the
+** Beta Release License Agreement.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain
+** additional rights. These rights are described in the Nokia Qt LGPL
+** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this
+** package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 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 the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+** If you are unsure which license is appropriate for your use, please
+** contact the sales department at qt-sales@nokia.com.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <QList>
+#include <QMap>
+#include <QTextStream>
+#include <QString>
+#include <QStringList>
+#include <QDir>
+#include <QTime>
+#include <QApplication>
+#include <QDebug>
+
+#include <qtconcurrentmap.h>
+
+#ifndef QT_NO_CONCURRENT
+
+using namespace QtConcurrent;
+
+/*
+    Utility function that recursivily searches for files.
+*/
+QStringList findFiles(const QString &startDir, QStringList filters)
+{
+    QStringList names;
+    QDir dir(startDir);
+
+    foreach (QString file, dir.entryList(filters, QDir::Files))
+        names += startDir + "/" + file;
+
+    foreach (QString subdir, dir.entryList(QDir::AllDirs | QDir::NoDotAndDotDot))
+        names += findFiles(startDir + "/" + subdir, filters);
+    return names;
+}
+
+typedef QMap<QString, int> WordCount;
+
+/*
+    Single threaded word counter function.
+*/
+WordCount singleThreadedWordCount(QStringList files)
+{
+    WordCount wordCount;
+    foreach (QString file, files) {
+        QFile f(file);
+        f.open(QIODevice::ReadOnly);
+        QTextStream textStream(&f);
+        while (textStream.atEnd() == false)
+            foreach(QString word, textStream.readLine().split(" "))
+                wordCount[word] += 1;
+
+    }
+    return wordCount;
+}
+
+
+// countWords counts the words in a single file. This function is
+// called in parallel by several threads and must be thread
+// safe.
+WordCount countWords(const QString &file)
+{
+    QFile f(file);
+    f.open(QIODevice::ReadOnly);
+    QTextStream textStream(&f);
+    WordCount wordCount;
+
+    while (textStream.atEnd() == false)
+        foreach (QString word, textStream.readLine().split(" "))
+            wordCount[word] += 1;
+
+    return wordCount;
+}
+
+// reduce adds the results from map to the final
+// result. This functor will only be called by one thread
+// at a time.
+void reduce(WordCount &result, const WordCount &w)
+{
+    QMapIterator<QString, int> i(w);
+    while (i.hasNext()) {
+        i.next();
+        result[i.key()] += i.value();
+    }
+}
+
+int main(int argc, char** argv)
+{
+    QApplication app(argc, argv);
+    qDebug() << "finding files...";
+    QStringList files = findFiles("../../", QStringList() << "*.cpp" << "*.h");
+    qDebug() << files.count() << "files";
+
+    qDebug() << "warmup";
+    {
+        QTime time;
+        time.start();
+        WordCount total = singleThreadedWordCount(files);
+    }
+
+    qDebug() << "warmup done";
+
+    int singleThreadTime = 0;
+    {
+        QTime time;
+        time.start();
+        WordCount total = singleThreadedWordCount(files);
+        singleThreadTime = time.elapsed();
+        qDebug() << "single thread" << singleThreadTime;
+    }
+
+    int mapReduceTime = 0;
+    {
+        QTime time;
+        time.start();
+        WordCount total = mappedReduced(files, countWords, reduce);
+        mapReduceTime = time.elapsed();
+        qDebug() << "MapReduce" << mapReduceTime;
+    }
+    qDebug() << "MapReduce speedup x" << ((double)singleThreadTime - (double)mapReduceTime) / (double)mapReduceTime + 1;
+}
+
+#else
+
+int main()
+{
+	qDebug() << "Qt Concurrent is not yet supported on this platform";
+}
+
+#endif