qt5base-lts/examples/qtestlib/tutorial5/containers.cpp

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/****************************************************************************
**
** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
** Contact: http://www.qt-project.org/legal
**
** This file is part of the test suite of the Qt Toolkit.
**
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**
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** the documentation and/or other materials provided with the
** distribution.
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** of its contributors may be used to endorse or promote products derived
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// This file contains benchmarks for comparing QVector against std::vector
#include <QtCore>
#include <QVector>
#include <vector>
#include <qtest.h>
template <typename T> // T is the item type
class UseCases {
public:
virtual ~UseCases() {}
// Use case: Insert \a size items into the vector.
virtual void insert(int size) = 0;
// Use case: Lookup \a size items from the vector.
virtual void lookup(int size) = 0;
};
template <typename T>
T * f(T *ts) // dummy function to prevent code from being optimized away by the compiler
{
return ts;
}
// This subclass implements the use cases using QVector as efficiently as possible.
template <typename T>
class UseCases_QVector : public UseCases<T>
{
void insert(int size)
{
QVector<T> v;
T t;
QBENCHMARK {
for (int i = 0; i < size; ++i)
v.append(t);
}
}
void lookup(int size)
{
QVector<T> v;
T t;
for (int i = 0; i < size; ++i)
v.append(t);
T *ts = new T[size];
QBENCHMARK {
for (int i = 0; i < size; ++i)
ts[i] = v.value(i);
}
f<T>(ts);
delete[] ts;
}
};
// This subclass implements the use cases using std::vector as efficiently as possible.
template <typename T>
class UseCases_stdvector : public UseCases<T>
{
void insert(int size)
{
std::vector<T> v;
T t;
QBENCHMARK {
for (int i = 0; i < size; ++i)
v.push_back(t);
}
}
void lookup(int size)
{
std::vector<T> v;
T t;
for (int i = 0; i < size; ++i)
v.push_back(t);
T *ts = new T[size];
QBENCHMARK {
for (int i = 0; i < size; ++i)
ts[i] = v[i];
}
f<T>(ts);
delete[] ts;
}
};
struct Large { // A "large" item type
int x[1000];
};
// Symbian devices typically have limited memory
# define LARGE_MAX_SIZE 20000
class tst_vector_vs_std : public QObject
{
Q_OBJECT
public:
tst_vector_vs_std()
{
useCases_QVector_int = new UseCases_QVector<int>;
useCases_stdvector_int = new UseCases_stdvector<int>;
useCases_QVector_Large = new UseCases_QVector<Large>;
useCases_stdvector_Large = new UseCases_stdvector<Large>;
}
private:
UseCases<int> *useCases_QVector_int;
UseCases<int> *useCases_stdvector_int;
UseCases<Large> *useCases_QVector_Large;
UseCases<Large> *useCases_stdvector_Large;
private slots:
void insert_int_data();
void insert_int();
void insert_Large_data();
void insert_Large();
void lookup_int_data();
void lookup_int();
void lookup_Large_data();
void lookup_Large();
};
void tst_vector_vs_std::insert_int_data()
{
QTest::addColumn<bool>("useStd");
QTest::addColumn<int>("size");
for (int size = 10; size < 20000; size += 100) {
const QByteArray sizeString = QByteArray::number(size);
QTest::newRow(("std::vector-int--" + sizeString).constData()) << true << size;
QTest::newRow(("QVector-int--" + sizeString).constData()) << false << size;
}
}
void tst_vector_vs_std::insert_int()
{
QFETCH(bool, useStd);
QFETCH(int, size);
if (useStd)
useCases_stdvector_int->insert(size);
else
useCases_QVector_int->insert(size);
}
void tst_vector_vs_std::insert_Large_data()
{
QTest::addColumn<bool>("useStd");
QTest::addColumn<int>("size");
for (int size = 10; size < LARGE_MAX_SIZE; size += 100) {
const QByteArray sizeString = QByteArray::number(size);
QTest::newRow(("std::vector-Large--" + sizeString).constData()) << true << size;
QTest::newRow(("QVector-Large--" + sizeString).constData()) << false << size;
}
}
void tst_vector_vs_std::insert_Large()
{
QFETCH(bool, useStd);
QFETCH(int, size);
if (useStd)
useCases_stdvector_Large->insert(size);
else
useCases_QVector_Large->insert(size);
}
//! [1]
void tst_vector_vs_std::lookup_int_data()
{
QTest::addColumn<bool>("useStd");
QTest::addColumn<int>("size");
for (int size = 10; size < 20000; size += 100) {
const QByteArray sizeString = QByteArray::number(size);
QTest::newRow(("std::vector-int--" + sizeString).constData()) << true << size;
QTest::newRow(("QVector-int--" + sizeString).constData()) << false << size;
}
}
//! [1]
//! [2]
void tst_vector_vs_std::lookup_int()
{
QFETCH(bool, useStd);
QFETCH(int, size);
if (useStd)
useCases_stdvector_int->lookup(size); // Create a std::vector and run the benchmark.
else
useCases_QVector_int->lookup(size); // Create a QVector and run the benchmark.
}
//! [2]
void tst_vector_vs_std::lookup_Large_data()
{
QTest::addColumn<bool>("useStd");
QTest::addColumn<int>("size");
for (int size = 10; size < LARGE_MAX_SIZE; size += 100) {
const QByteArray sizeString = QByteArray::number(size);
QTest::newRow(("std::vector-Large--" + sizeString).constData()) << true << size;
QTest::newRow(("QVector-Large--" + sizeString).constData()) << false << size;
}
}
void tst_vector_vs_std::lookup_Large()
{
QFETCH(bool, useStd);
QFETCH(int, size);
if (useStd)
useCases_stdvector_Large->lookup(size);
else
useCases_QVector_Large->lookup(size);
}
QTEST_MAIN(tst_vector_vs_std)
#include "main.moc"