qt5base-lts/examples/qtconcurrent/wordcount/main.cpp
David Boddie 0748751c9f Squashed commit of the changes from the mobile-examples repository
(4.7-generated-declarative branch).
2011-05-23 14:24:07 +02:00

186 lines
5.4 KiB
C++

/****************************************************************************
**
** 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
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** $QT_END_LICENSE$
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****************************************************************************/
#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...";
#ifdef Q_WS_MAEMO_5
QStringList files = findFiles("/usr/", QStringList() << "*.sh");
#else
QStringList files = findFiles("../../", QStringList() << "*.cpp" << "*.h");
#endif
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
#include <QLabel>
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
QString text("Qt Concurrent is not yet supported on this platform");
QLabel *label = new QLabel(text);
label->setWordWrap(true);
#if defined(Q_WS_S60) || defined(Q_WS_MAEMO_5)
label->showMaximized();
#else
label->show();
#endif
qDebug() << text;
app.exec();
}
#endif