05fc3aef53
Replace the current license disclaimer in files by a SPDX-License-Identifier. Files that have to be modified by hand are modified. License files are organized under LICENSES directory. Task-number: QTBUG-67283 Change-Id: Id880c92784c40f3bbde861c0d93f58151c18b9f1 Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org> Reviewed-by: Lars Knoll <lars.knoll@qt.io> Reviewed-by: Jörg Bornemann <joerg.bornemann@qt.io>
119 lines
3.1 KiB
C++
119 lines
3.1 KiB
C++
// Copyright (C) 2016 The Qt Company Ltd.
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// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
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#include <QList>
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#include <QMap>
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#include <QTextStream>
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#include <QString>
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#include <QStringList>
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#include <QDir>
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#include <QElapsedTimer>
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#include <QApplication>
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#include <QDebug>
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#include <qtconcurrentmap.h>
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using namespace QtConcurrent;
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/*
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Utility function that recursivily searches for files.
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*/
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QStringList findFiles(const QString &startDir, const QStringList &filters)
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{
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QStringList names;
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QDir dir(startDir);
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const auto files = dir.entryList(filters, QDir::Files);
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for (const QString &file : files)
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names += startDir + '/' + file;
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const auto subdirs = dir.entryList(QDir::AllDirs | QDir::NoDotAndDotDot);
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for (const QString &subdir : subdirs)
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names += findFiles(startDir + '/' + subdir, filters);
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return names;
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}
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typedef QMap<QString, int> WordCount;
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/*
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Single threaded word counter function.
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*/
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WordCount singleThreadedWordCount(const QStringList &files)
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{
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WordCount wordCount;
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for (const QString &file : files) {
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QFile f(file);
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f.open(QIODevice::ReadOnly);
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QTextStream textStream(&f);
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while (!textStream.atEnd()) {
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const auto words = textStream.readLine().split(' ');
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for (const QString &word : words)
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wordCount[word] += 1;
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}
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}
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return wordCount;
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}
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// countWords counts the words in a single file. This function is
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// called in parallel by several threads and must be thread
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// safe.
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WordCount countWords(const QString &file)
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{
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QFile f(file);
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f.open(QIODevice::ReadOnly);
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QTextStream textStream(&f);
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WordCount wordCount;
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while (!textStream.atEnd()) {
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const auto words = textStream.readLine().split(' ');
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for (const QString &word : words)
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wordCount[word] += 1;
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}
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return wordCount;
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}
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// reduce adds the results from map to the final
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// result. This functor will only be called by one thread
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// at a time.
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void reduce(WordCount &result, const WordCount &w)
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{
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for (auto i = w.begin(), end = w.end(); i != end; ++i)
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result[i.key()] += i.value();
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}
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int main(int argc, char** argv)
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{
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QApplication app(argc, argv);
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qDebug() << "finding files...";
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QStringList files = findFiles("../../", QStringList() << "*.cpp" << "*.h");
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qDebug() << files.count() << "files";
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qDebug() << "warmup";
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{
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WordCount total = singleThreadedWordCount(files);
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}
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qDebug() << "warmup done";
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int singleThreadTime = 0;
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{
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QElapsedTimer timer;
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timer.start();
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WordCount total = singleThreadedWordCount(files);
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singleThreadTime = timer.elapsed();
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qDebug() << "single thread" << singleThreadTime;
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}
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int mapReduceTime = 0;
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{
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QElapsedTimer timer;
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timer.start();
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WordCount total = mappedReduced(files, countWords, reduce).result();
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mapReduceTime = timer.elapsed();
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qDebug() << "MapReduce" << mapReduceTime;
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}
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qDebug() << "MapReduce speedup x" << ((double)singleThreadTime - (double)mapReduceTime) / (double)mapReduceTime + 1;
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}
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