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tst_QDateTime: rework initialization of local-time-types

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There's no need to check the year or day-of-month (which involve
calendrical calculations) when we can perfectly well just check the
Julian Day number that's implied by the day-number parameters to
setType(), which could just as well return the LocalTimeType to be
assigned to the relevant parameter instead of doing the setting
itself. With that rearrangement, making it into a private static
method, the members it's used to initialize can then be const and
initialized during construction.

Change-Id: Ib7d295c3fbb9b90652952627456cdfb6176b8119
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
This commit is contained in:
Edward Welbourne 2023-04-28 10:57:00 +02:00
parent 7d75039482
commit 89febde32f
1 changed files with 29 additions and 27 deletions
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56
tests/auto/corelib/time/qdatetime/tst_qdatetime.cpp
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@ -151,12 +151,34 @@ private Q_SLOTS:
#endif
private:
/*
Various zones close to UTC (notably Iceland, the WET zones and several in
West Africa) or nominally assigned to it historically (north Canada, the
Antarctic) and those that have crossed the international date-line (by
skipping or repeating a day) don't have a consistent answer to "which side
of UTC is it ?" So the various LocalTimeType members may be different.
*/
enum LocalTimeType { LocalTimeIsUtc = 0, LocalTimeAheadOfUtc = 1, LocalTimeBehindUtc = -1};
LocalTimeType solarMeanType, epochTimeType, futureTimeType;
const LocalTimeType solarMeanType, epochTimeType, futureTimeType;
static constexpr auto UTC = QTimeZone::UTC;
static constexpr qint64 epochJd = Q_INT64_C(2440588);
int preZoneFix;
bool zoneIsCET;
static LocalTimeType timeTypeFor(qint64 jand, qint64 juld)
{
constexpr uint day = 24 * 3600; // in seconds
QDateTime jan = QDateTime::fromSecsSinceEpoch(jand * day);
QDateTime jul = QDateTime::fromSecsSinceEpoch(juld * day);
if (jan.date().toJulianDay() < jand + epochJd || jul.date().toJulianDay() < juld + epochJd)
return LocalTimeBehindUtc;
if (jan.date().toJulianDay() > jand + epochJd || jul.date().toJulianDay() > juld + epochJd
|| jan.time().hour() > 0 || jul.time().hour() > 0) {
return LocalTimeAheadOfUtc;
}
return LocalTimeIsUtc;
}
class TimeZoneRollback
{
const QByteArray prior;
@ -184,7 +206,12 @@ private:
Q_DECLARE_METATYPE(Qt::TimeSpec)
Q_DECLARE_METATYPE(Qt::DateFormat)
tst_QDateTime::tst_QDateTime()
tst_QDateTime::tst_QDateTime() :
// UTC starts of January and July in the commented years:
solarMeanType(timeTypeFor(-62091, -61910)), // 1800
epochTimeType(timeTypeFor(0, 181)), // 1970
// Use stable future, to which current rule is extrapolated, as surrogate for variable current:
futureTimeType(timeTypeFor(24837, 25018)) // 2038
{
/*
Due to some jurisdictions changing their zones and rules, it's possible
@ -198,7 +225,6 @@ tst_QDateTime::tst_QDateTime()
might not be properly handled by our work-arounds for the MS backend and
32-bit time_t; so don't probe them here.
*/
constexpr uint day = 24 * 3600; // in seconds
zoneIsCET = (QDateTime(QDate(2038, 1, 19), QTime(4, 14, 7)).toSecsSinceEpoch() == 0x7fffffff
// Entries a year apart robustly differ by multiples of day.
&& QDate(2015, 7, 1).startOfDay().toSecsSinceEpoch() == 1435701600
@ -228,30 +254,6 @@ tst_QDateTime::tst_QDateTime()
Q_ASSERT(preZoneFix > -7200 && preZoneFix < 7200);
// So it's OK to add it to a QTime() between 02:00 and 22:00, but otherwise
// we must add it to the QDateTime constructed from it.
/*
Various zones close to UTC (notably Iceland, the WET zones and several in
West Africa) or nominally assigned to it historically (north Canada, the
Antarctic) and those that have crossed the international date-line (by
skipping or repeating a day) don't have a consistent answer to "which side
of UTC is it ?" So the three LocalTimeType members may be different.
*/
const auto setType = [day](int year, qint64 jand, qint64 juld, LocalTimeType &set) {
QDateTime jan = QDateTime::fromSecsSinceEpoch(jand * day);
QDateTime jul = QDateTime::fromSecsSinceEpoch(juld * day);
if (jan.date().year() < year || jul.date().month() < 7) {
set = LocalTimeBehindUtc;
} else if (jan.time().hour() > 0 || jul.time().hour() > 0
|| jan.date().day() > 1 || jul.date().day() > 1) {
set = LocalTimeAheadOfUtc;
} else {
set = LocalTimeIsUtc;
}
};
// UTC starts of January and July in the given years:
setType(1800, -62091, -61910, solarMeanType);
setType(1970, 0, 181, epochTimeType);
setType(2038, 24837, 25018, futureTimeType);
}
void tst_QDateTime::initTestCase()