benchmark.cc

/* Copyright 2013 Olivier Goffart <[email protected]>
http://woboq.com/blog/qmap_qhash_benchmark.html
*/
#include <QtCore/QtCore>
#include <unordered_map>
#ifndef CONTAINER
#error CONTAINER must be defined to QMap, QHash, std::map or std::unordered_map
#endif
namespace std{
/* std::hash specialization for QString so it can be used
* as a key in std::unordered_map */
template<class Key> struct hash;
template<> struct hash<QString> {
typedef QString Key;
typedef uint result_type;
inline uint operator()(const QString &s) const { return qHash(s); }
};
}
int main(int argc, char **argv) {
if (argc < 2)
qFatal(""Missing number of element to add"");
QByteArray a = argv[1];
uint num = a.toUInt();
// creates an array of random keys
QVector<QString> strs(num);
for (int i=0; i < num; ++i)
strs[i] = qvariant_cast<QString>(qrand());
CONTAINER<QString, QString> c;
for (uint i = 0; i < num; ++i) {
QString &k = strs[i];
c[k] = QString::number(i);
}
quint64 it = 0;
const QString *arr = strs.constData();
QElapsedTimer t;
t.start();
while (t.elapsed() < 1000) {
const QString &k = arr[(++it)*797%num];
c[k]; // perform a lookup
}
qDebug() << it/1000;
}