qt5base-lts/examples/qtconcurrent/wordcount/main.cpp
Jason McDonald 5635823e17 Remove "All rights reserved" line from license headers.
As in the past, to avoid rewriting various autotests that contain
line-number information, an extra blank line has been inserted at the
end of the license text to ensure that this commit does not change the
total number of lines in the license header.

Change-Id: I311e001373776812699d6efc045b5f742890c689
Reviewed-by: Rohan McGovern <rohan.mcgovern@nokia.com>
2012-01-30 03:54:59 +01:00

178 lines
5.1 KiB
C++

/****************************************************************************
**
** Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/
**
** 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
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
**
** $QT_END_LICENSE$
**
****************************************************************************/
#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
#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);
label->show();
qDebug() << text;
app.exec();
}
#endif