Deduplicate list-building code in QDateTime benchmark

Aside from the start-date and the end-date, and a variant with a
time-zone, the lists various tests were building were all built the
same way; so pack that up as a pair of functions (one without
time-zone, one with) to save duplication. Make the list in each
function const, ready for conversion of foreach loops to ranged for.

In the process, replace QList with QVector, reserve space before we
populate and use auto for the now-const list variables it's saved in.

Change-Id: I7d8cce459a4d6111cd645e8d3966ad769ab7e201
Reviewed-by: Marc Mutz <marc.mutz@kdab.com>

1 files changed, 57 insertions, 108 deletions

diff --git a/tests/benchmarks/corelib/time/qdatetime/main.cpp b/tests/benchmarks/corelib/time/qdatetime/main.cpp
index e616181bea..2730e7e18b 100644
--- a/tests/benchmarks/corelib/time/qdatetime/main.cpp
+++ b/tests/benchmarks/corelib/time/qdatetime/main.cpp
@@ -29,6 +29,7 @@
 #include <QDateTime>
 #include <QTimeZone>
 #include <QTest>
+#include <QVector>
 #include <qdebug.h>
 
 class tst_QDateTime : public QObject
@@ -49,6 +50,9 @@ class tst_QDateTime : public QObject
         JULIAN_DAY_2060 = 2473460
     };
 
+    static QVector<QDateTime> daily(qint64 start, qint64 end);
+    static QVector<QDateTime> norse(qint64 start, qint64 end);
+
 private Q_SLOTS:
     void create();
     void isNull();
@@ -98,6 +102,25 @@ private Q_SLOTS:
     void fromMSecsSinceEpochTz();
 };
 
+QVector<QDateTime> tst_QDateTime::daily(qint64 start, qint64 end)
+{
+    QVector<QDateTime> list;
+    list.reserve(end - start);
+    for (int jd = start; jd < end; ++jd)
+        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
+    return list;
+}
+
+QVector<QDateTime> tst_QDateTime::norse(qint64 start, qint64 end)
+{
+    const QTimeZone cet("Europe/Oslo");
+    QVector<QDateTime> list;
+    list.reserve(end - start);
+    for (int jd = start; jd < end; ++jd)
+        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0), cet));
+    return list;
+}
+
 void tst_QDateTime::create()
 {
     QBENCHMARK {
@@ -110,9 +133,7 @@ void tst_QDateTime::create()
 
 void tst_QDateTime::isNull()
 {
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2020; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
+    const auto list = daily(JULIAN_DAY_2010, JULIAN_DAY_2020);
     QBENCHMARK {
         foreach (const QDateTime &test, list)
             test.isNull();
@@ -121,9 +142,7 @@ void tst_QDateTime::isNull()
 
 void tst_QDateTime::isValid()
 {
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2020; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
+    const auto list = daily(JULIAN_DAY_2010, JULIAN_DAY_2020);
     QBENCHMARK {
         foreach (const QDateTime &test, list)
             test.isValid();
@@ -132,9 +151,7 @@ void tst_QDateTime::isValid()
 
 void tst_QDateTime::date()
 {
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2020; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
+    const auto list = daily(JULIAN_DAY_2010, JULIAN_DAY_2020);
     QBENCHMARK {
         foreach (const QDateTime &test, list)
             test.date();
@@ -143,9 +160,7 @@ void tst_QDateTime::date()
 
 void tst_QDateTime::time()
 {
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2020; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
+    const auto list = daily(JULIAN_DAY_2010, JULIAN_DAY_2020);
     QBENCHMARK {
         foreach (const QDateTime &test, list)
             test.time();
@@ -154,9 +169,7 @@ void tst_QDateTime::time()
 
 void tst_QDateTime::timeSpec()
 {
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2020; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
+    const auto list = daily(JULIAN_DAY_2010, JULIAN_DAY_2020);
     QBENCHMARK {
         foreach (const QDateTime &test, list)
             test.timeSpec();
@@ -165,9 +178,7 @@ void tst_QDateTime::timeSpec()
 
 void tst_QDateTime::offsetFromUtc()
 {
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2020; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
+    const auto list = daily(JULIAN_DAY_2010, JULIAN_DAY_2020);
     QBENCHMARK {
         foreach (const QDateTime &test, list)
             test.offsetFromUtc();
@@ -176,9 +187,7 @@ void tst_QDateTime::offsetFromUtc()
 
 void tst_QDateTime::timeZoneAbbreviation()
 {
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2020; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
+    const auto list = daily(JULIAN_DAY_2010, JULIAN_DAY_2020);
     QBENCHMARK {
         foreach (const QDateTime &test, list)
             test.timeZoneAbbreviation();
@@ -187,9 +196,7 @@ void tst_QDateTime::timeZoneAbbreviation()
 
 void tst_QDateTime::toMSecsSinceEpoch()
 {
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2020; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
+    const auto list = daily(JULIAN_DAY_2010, JULIAN_DAY_2020);
     QBENCHMARK {
         foreach (const QDateTime &test, list)
             test.toMSecsSinceEpoch();
@@ -198,9 +205,7 @@ void tst_QDateTime::toMSecsSinceEpoch()
 
 void tst_QDateTime::toMSecsSinceEpoch1950()
 {
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_1950; jd < JULIAN_DAY_1960; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
+    const auto list = daily(JULIAN_DAY_1950, JULIAN_DAY_1960);
     QBENCHMARK {
         foreach (const QDateTime &test, list)
             test.toMSecsSinceEpoch();
@@ -209,9 +214,7 @@ void tst_QDateTime::toMSecsSinceEpoch1950()
 
 void tst_QDateTime::toMSecsSinceEpoch2050()
 {
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_2050; jd < JULIAN_DAY_2060; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
+    const auto list = daily(JULIAN_DAY_2050, JULIAN_DAY_2060);
     QBENCHMARK {
         foreach (const QDateTime &test, list)
             test.toMSecsSinceEpoch();
@@ -220,11 +223,8 @@ void tst_QDateTime::toMSecsSinceEpoch2050()
 
 void tst_QDateTime::toMSecsSinceEpochTz()
 {
-    QTimeZone cet = QTimeZone("Europe/Oslo");
     qint64 result;
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2020; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0), cet));
+    const auto list = norse(JULIAN_DAY_2010, JULIAN_DAY_2020);
     QBENCHMARK {
         foreach (const QDateTime &test, list)
             result = test.toMSecsSinceEpoch();
@@ -234,11 +234,8 @@ void tst_QDateTime::toMSecsSinceEpochTz()
 
 void tst_QDateTime::toMSecsSinceEpoch1950Tz()
 {
-    QTimeZone cet = QTimeZone("Europe/Oslo");
     qint64 result;
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_1950; jd < JULIAN_DAY_1960; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0), cet));
+    const auto list = norse(JULIAN_DAY_1950, JULIAN_DAY_1960);
     QBENCHMARK {
         foreach (const QDateTime &test, list)
             result = test.toMSecsSinceEpoch();
@@ -248,11 +245,8 @@ void tst_QDateTime::toMSecsSinceEpoch1950Tz()
 
 void tst_QDateTime::toMSecsSinceEpoch2050Tz()
 {
-    QTimeZone cet = QTimeZone("Europe/Oslo");
     qint64 result;
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_2050; jd < JULIAN_DAY_2060; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0), cet));
+    const auto list = norse(JULIAN_DAY_2050, JULIAN_DAY_2060);
     QBENCHMARK {
         foreach (const QDateTime &test, list)
             result = test.toMSecsSinceEpoch();
@@ -262,9 +256,7 @@ void tst_QDateTime::toMSecsSinceEpoch2050Tz()
 
 void tst_QDateTime::setDate()
 {
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2020; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
+    const auto list = daily(JULIAN_DAY_2010, JULIAN_DAY_2020);
     QBENCHMARK {
         foreach (QDateTime test, list)
             test.setDate(QDate::fromJulianDay(JULIAN_DAY_2010));
@@ -273,9 +265,7 @@ void tst_QDateTime::setDate()
 
 void tst_QDateTime::setTime()
 {
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2020; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
+    const auto list = daily(JULIAN_DAY_2010, JULIAN_DAY_2020);
     QBENCHMARK {
         foreach (QDateTime test, list)
             test.setTime(QTime(12, 0, 0));
@@ -284,9 +274,7 @@ void tst_QDateTime::setTime()
 
 void tst_QDateTime::setTimeSpec()
 {
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2020; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
+    const auto list = daily(JULIAN_DAY_2010, JULIAN_DAY_2020);
     QBENCHMARK {
         foreach (QDateTime test, list)
             test.setTimeSpec(Qt::UTC);
@@ -295,9 +283,7 @@ void tst_QDateTime::setTimeSpec()
 
 void tst_QDateTime::setOffsetFromUtc()
 {
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2020; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
+    const auto list = daily(JULIAN_DAY_2010, JULIAN_DAY_2020);
     QBENCHMARK {
         foreach (QDateTime test, list)
             test.setOffsetFromUtc(3600);
@@ -307,9 +293,7 @@ void tst_QDateTime::setOffsetFromUtc()
 void tst_QDateTime::setMSecsSinceEpoch()
 {
     qint64 msecs = qint64(JULIAN_DAY_2010 - JULIAN_DAY_1970 + 180) * MSECS_PER_DAY;
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2020; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
+    const auto list = daily(JULIAN_DAY_2010, JULIAN_DAY_2020);
     QBENCHMARK {
         foreach (QDateTime test, list)
             test.setMSecsSinceEpoch(msecs);
@@ -318,11 +302,8 @@ void tst_QDateTime::setMSecsSinceEpoch()
 
 void tst_QDateTime::setMSecsSinceEpochTz()
 {
-    QTimeZone cet = QTimeZone("Europe/Oslo");
-    QList<QDateTime> list;
     const qint64 msecs = qint64(JULIAN_DAY_2010 - JULIAN_DAY_1970 + 180) * MSECS_PER_DAY;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2020; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0), cet));
+    const auto list = norse(JULIAN_DAY_2010, JULIAN_DAY_2020);
     QBENCHMARK {
         foreach (QDateTime test, list)
             test.setMSecsSinceEpoch(msecs);
@@ -331,9 +312,7 @@ void tst_QDateTime::setMSecsSinceEpochTz()
 
 void tst_QDateTime::toString()
 {
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2011; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
+    const auto list = daily(JULIAN_DAY_2010, JULIAN_DAY_2011);
     QBENCHMARK {
         foreach (const QDateTime &test, list)
             test.toString(QStringLiteral("yyy-MM-dd hh:mm:ss.zzz t"));
@@ -342,9 +321,7 @@ void tst_QDateTime::toString()
 
 void tst_QDateTime::toStringTextFormat()
 {
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2011; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
+    const auto list = daily(JULIAN_DAY_2010, JULIAN_DAY_2011);
     QBENCHMARK {
         foreach (const QDateTime &test, list)
             test.toString(Qt::TextDate);
@@ -353,9 +330,7 @@ void tst_QDateTime::toStringTextFormat()
 
 void tst_QDateTime::toStringIsoFormat()
 {
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2011; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
+    const auto list = daily(JULIAN_DAY_2010, JULIAN_DAY_2011);
     QBENCHMARK {
         foreach (const QDateTime &test, list)
             test.toString(Qt::ISODate);
@@ -364,10 +339,8 @@ void tst_QDateTime::toStringIsoFormat()
 
 void tst_QDateTime::addDays()
 {
-    QList<QDateTime> list;
+    const auto list = daily(JULIAN_DAY_2010, JULIAN_DAY_2020);
     QDateTime next;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2020; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
     QBENCHMARK {
         foreach (const QDateTime &test, list)
             next = test.addDays(1);
@@ -377,10 +350,7 @@ void tst_QDateTime::addDays()
 
 void tst_QDateTime::addDaysTz()
 {
-    QTimeZone cet = QTimeZone("Europe/Oslo");
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2020; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0), cet));
+    const auto list = norse(JULIAN_DAY_2010, JULIAN_DAY_2020);
     QBENCHMARK {
         foreach (const QDateTime &test, list)
             QDateTime result = test.addDays(1);
@@ -389,10 +359,8 @@ void tst_QDateTime::addDaysTz()
 
 void tst_QDateTime::addMSecs()
 {
-    QList<QDateTime> list;
+    const auto list = daily(JULIAN_DAY_2010, JULIAN_DAY_2020);
     QDateTime next;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2020; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
     QBENCHMARK {
         foreach (const QDateTime &test, list)
             next = test.addMSecs(1);
@@ -402,10 +370,7 @@ void tst_QDateTime::addMSecs()
 
 void tst_QDateTime::addMSecsTz()
 {
-    QTimeZone cet = QTimeZone("Europe/Oslo");
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2020; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0), cet));
+    const auto list = norse(JULIAN_DAY_2010, JULIAN_DAY_2020);
     QBENCHMARK {
         foreach (const QDateTime &test, list)
             QDateTime result = test.addMSecs(1);
@@ -414,9 +379,7 @@ void tst_QDateTime::addMSecsTz()
 
 void tst_QDateTime::toTimeSpec()
 {
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2020; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
+    const auto list = daily(JULIAN_DAY_2010, JULIAN_DAY_2020);
     QBENCHMARK {
         foreach (const QDateTime &test, list)
             test.toTimeSpec(Qt::UTC);
@@ -425,9 +388,7 @@ void tst_QDateTime::toTimeSpec()
 
 void tst_QDateTime::toOffsetFromUtc()
 {
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2020; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
+    const auto list = daily(JULIAN_DAY_2010, JULIAN_DAY_2020);
     QBENCHMARK {
         foreach (const QDateTime &test, list)
             test.toOffsetFromUtc(3600);
@@ -438,9 +399,7 @@ void tst_QDateTime::daysTo()
 {
     const QDateTime other = QDateTime::fromMSecsSinceEpoch(
         qint64(JULIAN_DAY_2010 - JULIAN_DAY_1970) * MSECS_PER_DAY);
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2020; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
+    const auto list = daily(JULIAN_DAY_2010, JULIAN_DAY_2020);
     QBENCHMARK {
         foreach (const QDateTime &test, list)
             test.daysTo(other);
@@ -451,9 +410,7 @@ void tst_QDateTime::msecsTo()
 {
     const QDateTime other = QDateTime::fromMSecsSinceEpoch(
         qint64(JULIAN_DAY_2010 - JULIAN_DAY_1970) * MSECS_PER_DAY);
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2020; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
+    const auto list = daily(JULIAN_DAY_2010, JULIAN_DAY_2020);
     QBENCHMARK {
         foreach (const QDateTime &test, list)
             test.msecsTo(other);
@@ -465,9 +422,7 @@ void tst_QDateTime::equivalent()
     bool result;
     const QDateTime other = QDateTime::fromMSecsSinceEpoch(
         qint64(JULIAN_DAY_2010 - JULIAN_DAY_1970) * MSECS_PER_DAY);
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2020; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
+    const auto list = daily(JULIAN_DAY_2010, JULIAN_DAY_2020);
     QBENCHMARK {
         foreach (const QDateTime &test, list)
             result = (test == other);
@@ -480,9 +435,7 @@ void tst_QDateTime::equivalentUtc()
     bool result = false;
     const QDateTime other = QDateTime::fromMSecsSinceEpoch(
         qint64(JULIAN_DAY_2010 - JULIAN_DAY_1970) * MSECS_PER_DAY, Qt::UTC);
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2020; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
+    const auto list = daily(JULIAN_DAY_2010, JULIAN_DAY_2020);
     QBENCHMARK {
         foreach (const QDateTime &test, list)
             result = (test == other);
@@ -495,9 +448,7 @@ void tst_QDateTime::lessThan()
     bool result = false;
     const QDateTime other = QDateTime::fromMSecsSinceEpoch(
         qint64(JULIAN_DAY_2010 - JULIAN_DAY_1970) * MSECS_PER_DAY);
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2020; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
+    const auto list = daily(JULIAN_DAY_2010, JULIAN_DAY_2020);
     QBENCHMARK {
         foreach (const QDateTime &test, list)
             result = (test < other);
@@ -510,9 +461,7 @@ void tst_QDateTime::lessThanUtc()
     bool result = false;
     const QDateTime other = QDateTime::fromMSecsSinceEpoch(
         qint64(JULIAN_DAY_2010 - JULIAN_DAY_1970) * MSECS_PER_DAY, Qt::UTC);
-    QList<QDateTime> list;
-    for (int jd = JULIAN_DAY_2010; jd < JULIAN_DAY_2020; ++jd)
-        list.append(QDateTime(QDate::fromJulianDay(jd), QTime::fromMSecsSinceStartOfDay(0)));
+    const auto list = daily(JULIAN_DAY_2010, JULIAN_DAY_2020);
     QBENCHMARK {
         foreach (const QDateTime &test, list)
             result = (test < other);