QRoundingDown: make the numerator a template parameter

It's always a constexpr (or static const that could be constexpr; fix
the cases of this while I'm here) or an integer literal, so we can, so
we might as well.

Change-Id: I61e9bcdb27f4a05f011ccce16b5f15d0dade0782
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
Reviewed-by: Marc Mutz <marc.mutz@qt.io>

9 files changed, 62 insertions, 62 deletions

diff --git a/src/corelib/time/qcalendar.cpp b/src/corelib/time/qcalendar.cpp
index a355df2100..a6801fe725 100644
--- a/src/corelib/time/qcalendar.cpp
+++ b/src/corelib/time/qcalendar.cpp
@@ -867,7 +867,7 @@ int QCalendarBackend::maximumMonthsInYear() const
  */
 int QCalendarBackend::dayOfWeek(qint64 jd) const
 {
-    return QRoundingDown::qMod(jd, 7) + 1;
+    return QRoundingDown::qMod<7>(jd) + 1;
 }
 
 // Month and week-day name look-ups (implemented in qlocale.cpp):
diff --git a/src/corelib/time/qcalendarmath_p.h b/src/corelib/time/qcalendarmath_p.h
index 885f5faba8..87609373df 100644
--- a/src/corelib/time/qcalendarmath_p.h
+++ b/src/corelib/time/qcalendarmath_p.h
@@ -35,11 +35,11 @@ namespace QRoundingDown {
   when that subtraction would underflow.
 */
 
-template<typename Int> constexpr Int qDiv(Int a, unsigned b)
+template<unsigned b, typename Int> constexpr Int qDiv(Int a)
 { return a < 0 ? (a + 1) / int(b) - 1 : a / int(b); }
 
-template<typename Int> constexpr Int qMod(Int a, unsigned b)
-{ return a - qDiv(a, b) * b; }
+template<unsigned b, typename Int> constexpr Int qMod(Int a)
+{ return a - qDiv<b>(a) * b; }
 
 } // QRoundingDown
 
diff --git a/src/corelib/time/qdatetime.cpp b/src/corelib/time/qdatetime.cpp
index f6e7c511cb..098b47e31a 100644
--- a/src/corelib/time/qdatetime.cpp
+++ b/src/corelib/time/qdatetime.cpp
@@ -2139,7 +2139,7 @@ QTime QTime::addMSecs(int ms) const
 {
     QTime t;
     if (isValid())
-        t.mds = QRoundingDown::qMod(ds() + ms, MSECS_PER_DAY);
+        t.mds = QRoundingDown::qMod<MSECS_PER_DAY>(ds() + ms);
     return t;
 }
 
@@ -2507,7 +2507,7 @@ typedef QDateTimePrivate::QDateTimeData QDateTimeData;
 // Converts milliseconds since the start of 1970 into a date and/or time:
 static qint64 msecsToJulianDay(qint64 msecs)
 {
-    return JULIAN_DAY_FOR_EPOCH + QRoundingDown::qDiv(msecs, MSECS_PER_DAY);
+    return JULIAN_DAY_FOR_EPOCH + QRoundingDown::qDiv<MSECS_PER_DAY>(msecs);
 }
 
 static QDate msecsToDate(qint64 msecs)
@@ -2517,7 +2517,7 @@ static QDate msecsToDate(qint64 msecs)
 
 static QTime msecsToTime(qint64 msecs)
 {
-    return QTime::fromMSecsSinceStartOfDay(QRoundingDown::qMod(msecs, MSECS_PER_DAY));
+    return QTime::fromMSecsSinceStartOfDay(QRoundingDown::qMod<MSECS_PER_DAY>(msecs));
 }
 
 // True if combining days with millis overflows; otherwise, stores result in *sumMillis
@@ -3053,7 +3053,7 @@ static QPair<QDate, QTime> getDateTime(const QDateTimeData &d)
 {
     auto status = getStatus(d);
     const qint64 msecs = getMSecs(d);
-    const qint64 days = QRoundingDown::qDiv(msecs, MSECS_PER_DAY);
+    const qint64 days = QRoundingDown::qDiv<MSECS_PER_DAY>(msecs);
     return { status.testFlag(QDateTimePrivate::ValidDate)
             ? QDate::fromJulianDay(JULIAN_DAY_FOR_EPOCH + days)
             : QDate(),
diff --git a/src/corelib/time/qgregoriancalendar.cpp b/src/corelib/time/qgregoriancalendar.cpp
index dc5a677f56..7151feeb04 100644
--- a/src/corelib/time/qgregoriancalendar.cpp
+++ b/src/corelib/time/qgregoriancalendar.cpp
@@ -73,7 +73,7 @@ bool QGregorianCalendar::validParts(int year, int month, int day)
 
 int QGregorianCalendar::weekDayOfJulian(qint64 jd)
 {
-    return qMod(jd, 7) + 1;
+    return qMod<7>(jd) + 1;
 }
 
 bool QGregorianCalendar::dateToJulianDay(int year, int month, int day, qint64 *jd) const
@@ -98,8 +98,8 @@ bool QGregorianCalendar::julianFromParts(int year, int month, int day, qint64 *j
     int    a = month < 3 ? 1 : 0;
     qint64 y = qint64(year) + 4800 - a;
     int    m = month + 12 * a - 3;
-    *jd = day + qDiv(153 * m + 2, 5) - 32045
-        + 365 * y + qDiv(y, 4) - qDiv(y, 100) + qDiv(y, 400);
+    *jd = day + qDiv<5>(153 * m + 2) - 32045
+        + 365 * y + qDiv<4>(y) - qDiv<100>(y) + qDiv<400>(y);
     return true;
 }
 
@@ -107,7 +107,7 @@ int QGregorianCalendar::yearStartWeekDay(int year)
 {
     // Equivalent to weekDayOfJulian(julianForParts({year, 1, 1})
     const int y = year - (year < 0 ? 800 : 801);
-    return qMod(y + qDiv(y, 4) - qDiv(y, 100) + qDiv(y, 400), 7) + 1;
+    return qMod<7>(y + qDiv<4>(y) - qDiv<100>(y) + qDiv<400>(y)) + 1;
 }
 
 int QGregorianCalendar::yearSharingWeekDays(QDate date)
@@ -169,19 +169,19 @@ QCalendar::YearMonthDay QGregorianCalendar::partsFromJulian(qint64 jd)
      * division (round to negative infinity), not c++11 integer division (round to zero)
      */
     qint64 a = jd + 32044;
-    qint64 b = qDiv(4 * a + 3, 146097);
-    int    c = a - qDiv(146097 * b, 4);
+    qint64 b = qDiv<146097>(4 * a + 3);
+    int    c = a - qDiv<4>(146097 * b);
 
-    int    d = qDiv(4 * c + 3, 1461);
-    int    e = c - qDiv(1461 * d, 4);
-    int    m = qDiv(5 * e + 2, 153);
+    int    d = qDiv<1461>(4 * c + 3);
+    int    e = c - qDiv<4>(1461 * d);
+    int    m = qDiv<153>(5 * e + 2);
 
-    int y = 100 * b + d - 4800 + qDiv(m, 10);
+    int y = 100 * b + d - 4800 + qDiv<10>(m);
 
     // Adjust for no year 0
     int year = y > 0 ? y : y - 1;
-    int month = m + 3 - 12 * qDiv(m, 10);
-    int day = e - qDiv(153 * m + 2, 5) + 1;
+    int month = m + 3 - 12 * qDiv<10>(m);
+    int day = e - qDiv<5>(153 * m + 2) + 1;
 
     return QCalendar::YearMonthDay(year, month, day);
 }
diff --git a/src/corelib/time/qislamiccivilcalendar.cpp b/src/corelib/time/qislamiccivilcalendar.cpp
index 238544105f..96b73dcd43 100644
--- a/src/corelib/time/qislamiccivilcalendar.cpp
+++ b/src/corelib/time/qislamiccivilcalendar.cpp
@@ -58,7 +58,7 @@ bool QIslamicCivilCalendar::isLeapYear(int year) const
         return false;
     if (year < 0)
         ++year;
-    return qMod(year * 11 + 14, 30) < 11;
+    return qMod<30>(year * 11 + 14) < 11;
 }
 
 bool QIslamicCivilCalendar::dateToJulianDay(int year, int month, int day, qint64 *jd) const
@@ -68,20 +68,20 @@ bool QIslamicCivilCalendar::dateToJulianDay(int year, int month, int day, qint64
         return false;
     if (year <= 0)
         ++year;
-    *jd = qDiv(10631 * year - 10617, 30)
-            + qDiv(325 * month - 320, 11)
+    *jd = qDiv<30>(10631 * year - 10617)
+            + qDiv<11>(325 * month - 320)
             + day + 1948439;
     return true;
 }
 
 QCalendar::YearMonthDay QIslamicCivilCalendar::julianDayToDate(qint64 jd) const
 {
-    const qint64 epoch = 1948440;
+    constexpr qint64 epoch = 1948440;
     const int32_t k2 = 30 * (jd - epoch) + 15;
-    const int32_t k1 = 11 * qDiv(qMod(k2, 10631), 30) + 5;
-    int y = qDiv(k2, 10631) + 1;
-    const int month = qDiv(k1, 325) + 1;
-    const int day = qDiv(qMod(k1, 325), 11) + 1;
+    const int32_t k1 = 11 * qDiv<30>(qMod<10631>(k2)) + 5;
+    int y = qDiv<10631>(k2) + 1;
+    const int month = qDiv<325>(k1) + 1;
+    const int day = qDiv<11>(qMod<325>(k1)) + 1;
     return QCalendar::YearMonthDay(y > 0 ? y : y - 1, month, day);
 }
 
diff --git a/src/corelib/time/qjalalicalendar.cpp b/src/corelib/time/qjalalicalendar.cpp
index 3bc38ec1b5..0b51211d15 100644
--- a/src/corelib/time/qjalalicalendar.cpp
+++ b/src/corelib/time/qjalalicalendar.cpp
@@ -13,16 +13,16 @@ using namespace QRoundingDown;
 
 // Constants
 
-static const qint64 cycleDays = 1029983;
-static const int cycleYears = 2820;
-static const double yearLength = 365.24219858156028368; // 365 + leapRatio;
-static const qint64 jalaliEpoch = 2121446; // 475/01/01 AP, start of 2820 cycle
+constexpr qint64 cycleDays = 1029983;
+constexpr int cycleYears = 2820;
+constexpr double yearLength = 365.24219858156028368; // 365 + leapRatio;
+constexpr qint64 jalaliEpoch = 2121446; // 475/01/01 AP, start of 2820 cycle
 
 // Calendar implementation
 
 static inline int cycle(qint64 jdn)
 {
-    return qDiv(jdn - jalaliEpoch, cycleDays);
+    return qDiv<cycleDays>(jdn - jalaliEpoch);
 }
 
 qint64 cycleStart(int cycleNo)
@@ -96,7 +96,7 @@ bool QJalaliCalendar::isLeapYear(int year) const
         return false;
     if (year < 0)
         year++;
-    return qMod((year + 2346) * 683, 2820) < 683;
+    return qMod<2820>((year + 2346) * 683) < 683;
 }
 
 bool QJalaliCalendar::isLunar() const
@@ -121,7 +121,7 @@ bool QJalaliCalendar::dateToJulianDay(int year, int month, int day, qint64 *jd)
         return false;
 
     const int y = year - (year < 0 ? 474 : 475);
-    const int c = qDiv(y, cycleYears);
+    const int c = qDiv<cycleYears>(y);
     const int yearInCycle = y - c * cycleYears;
     int dayInYear = day;
     for (int i = 1; i < month; ++i)
diff --git a/src/corelib/time/qjuliancalendar.cpp b/src/corelib/time/qjuliancalendar.cpp
index 627c92c48a..e1ea27b3d5 100644
--- a/src/corelib/time/qjuliancalendar.cpp
+++ b/src/corelib/time/qjuliancalendar.cpp
@@ -54,7 +54,7 @@ bool QJulianCalendar::isLeapYear(int year) const
     if (year == QCalendar::Unspecified || !year)
         return false;
 
-    return qMod(year < 0 ? year + 1 : year, 4) == 0;
+    return qMod<4>(year < 0 ? year + 1 : year) == 0;
 }
 
 // Julian Day 0 was January the first in the proleptic Julian calendar's 4713 BC
@@ -67,8 +67,8 @@ bool QJulianCalendar::dateToJulianDay(int year, int month, int day, qint64 *jd)
     if (year < 0)
         ++year;
     const qint64 c0 = month < 3 ? -1 : 0;
-    const qint64 j1 = qDiv(1461 * (year + c0), 4);
-    const qint64 j2 = qDiv(153 * month - 1836 * c0 - 457, 5);
+    const qint64 j1 = qDiv<4>(1461 * (year + c0));
+    const qint64 j2 = qDiv<5>(153 * month - 1836 * c0 - 457);
     *jd = j1 + j2 + day + 1721117;
     return true;
 }
@@ -77,12 +77,12 @@ QCalendar::YearMonthDay QJulianCalendar::julianDayToDate(qint64 jd) const
 {
     const qint64 y2 = jd - 1721118;
     const qint64 k2 = 4 * y2 + 3;
-    const qint64 k1 = 5 * qDiv(qMod(k2, 1461), 4) + 2;
-    const qint64 x1 = qDiv(k1, 153);
-    const qint64 c0 = qDiv(x1 + 2, 12);
-    const int y = qint16(qDiv(k2, 1461) + c0);
+    const qint64 k1 = 5 * qDiv<4>(qMod<1461>(k2)) + 2;
+    const qint64 x1 = qDiv<153>(k1);
+    const qint64 c0 = qDiv<12>(x1 + 2);
+    const int y = qint16(qDiv<1461>(k2) + c0);
     const int month = quint8(x1 - 12 * c0 + 3);
-    const int day = qDiv(qMod(k1, 153), 5) + 1;
+    const int day = qDiv<5>(qMod<153>(k1)) + 1;
     return QCalendar::YearMonthDay(y > 0 ? y : y - 1, month, day);
 }
 
diff --git a/src/corelib/time/qlocaltime.cpp b/src/corelib/time/qlocaltime.cpp
index cd3c7e5120..9056695967 100644
--- a/src/corelib/time/qlocaltime.cpp
+++ b/src/corelib/time/qlocaltime.cpp
@@ -312,7 +312,7 @@ inline bool secondsAndMillisOverflow(qint64 epochSeconds, qint64 millis, qint64
 // returns the local milliseconds, offset from UTC and DST status.
 QDateTimePrivate::ZoneState utcToLocal(qint64 utcMillis)
 {
-    const time_t epochSeconds = QRoundingDown::qDiv(utcMillis, MSECS_PER_SEC);
+    const time_t epochSeconds = QRoundingDown::qDiv<MSECS_PER_SEC>(utcMillis);
     const int msec = utcMillis - epochSeconds * MSECS_PER_SEC;
     Q_ASSERT(msec >= 0 && msec < MSECS_PER_SEC);
     if (qint64(epochSeconds) * MSECS_PER_SEC + msec != utcMillis) // time_t range too narrow
@@ -341,7 +341,7 @@ QDateTimePrivate::ZoneState utcToLocal(qint64 utcMillis)
 
 QString localTimeAbbbreviationAt(qint64 local, QDateTimePrivate::DaylightStatus dst)
 {
-    const qint64 localDays = QRoundingDown::qDiv(local, MSECS_PER_DAY);
+    const qint64 localDays = QRoundingDown::qDiv<MSECS_PER_DAY>(local);
     qint64 millis = local - localDays * MSECS_PER_DAY;
     Q_ASSERT(0 <= millis && millis < MSECS_PER_DAY); // Definition of QRD::qDiv.
     struct tm tmLocal = timeToTm(localDays, int(millis / MSECS_PER_SEC), dst);
@@ -356,7 +356,7 @@ QDateTimePrivate::ZoneState mapLocalTime(qint64 local, QDateTimePrivate::Dayligh
 {
     qint64 localSecs = local / MSECS_PER_SEC;
     qint64 millis = local - localSecs * MSECS_PER_SEC; // 0 or with same sign as local
-    const qint64 localDays = QRoundingDown::qDiv(localSecs, SECS_PER_DAY);
+    const qint64 localDays = QRoundingDown::qDiv<SECS_PER_DAY>(localSecs);
     qint64 daySecs = localSecs - localDays * SECS_PER_DAY;
     Q_ASSERT(0 <= daySecs && daySecs < SECS_PER_DAY); // Definition of QRD::qDiv.
 
@@ -368,7 +368,7 @@ QDateTimePrivate::ZoneState mapLocalTime(qint64 local, QDateTimePrivate::Dayligh
     // TODO: for glibc, we could use tmLocal.tm_gmtoff
     // That would give us offset directly, hence localSecs = offset + utcSecs
     // Provisional offset, until we have a revised localSeconds:
-    int offset = QRoundingDown::qDiv(local, MSECS_PER_SEC) - utcSecs;
+    int offset = QRoundingDown::qDiv<MSECS_PER_SEC>(local) - utcSecs;
     dst = tmLocal.tm_isdst > 0 ? QDateTimePrivate::DaylightTime : QDateTimePrivate::StandardTime;
     qint64 jd;
     if (Q_UNLIKELY(!QGregorianCalendar::julianFromParts(
diff --git a/src/corelib/time/qmilankoviccalendar.cpp b/src/corelib/time/qmilankoviccalendar.cpp
index 6c72787e36..428b0169d4 100644
--- a/src/corelib/time/qmilankoviccalendar.cpp
+++ b/src/corelib/time/qmilankoviccalendar.cpp
@@ -53,10 +53,10 @@ bool QMilankovicCalendar::isLeapYear(int year) const
         return false;
     if (year <= 0)
         ++year;
-    if (qMod(year, 4))
+    if (qMod<4>(year))
         return false;
-    if (qMod(year, 100) == 0) {
-        const qint16 century = qMod(qDiv(year, 100), 9);
+    if (qMod<100>(year) == 0) {
+        const qint16 century = qMod<9>(qDiv<100>(year));
         if (century != 2 && century != 6)
             return false;
     }
@@ -73,11 +73,11 @@ bool QMilankovicCalendar::dateToJulianDay(int year, int month, int day, qint64 *
     const qint16 c0 = month < 3 ? -1 : 0;
     const qint16 x1 = month - 12 * c0 - 3;
     const qint16 x4 = year + c0;
-    const qint16 x3 = qDiv(x4, 100);
-    const qint16 x2 = qMod(x4, 100);
-    *jd = qDiv(328718 * x3 + 6, 9)
-        + qDiv(36525 * x2 , 100)
-        + qDiv(153 * x1 + 2 , 5)
+    const qint16 x3 = qDiv<100>(x4);
+    const qint16 x2 = qMod<100>(x4);
+    *jd = qDiv<9>(328718 * x3 + 6)
+        + qDiv<100>(36525 * x2)
+        + qDiv<5>(153 * x1 + 2)
         + day + 1721119;
     return true;
 }
@@ -85,15 +85,15 @@ bool QMilankovicCalendar::dateToJulianDay(int year, int month, int day, qint64 *
 QCalendar::YearMonthDay  QMilankovicCalendar::julianDayToDate(qint64 jd) const
 {
     const qint64 k3 = 9 * (jd - 1721120) + 2;
-    const qint64 x3 = qDiv(k3, 328718);
-    const qint64 k2 = 100 * qDiv(qMod(k3, 328718), 9) + 99;
-    const qint64 k1 = qDiv(qMod(k2, 36525), 100) * 5 + 2;
-    const qint64 x2 = qDiv(k2, 36525);
-    const qint64 x1 = qDiv(5 * qDiv(qMod(k2, 36525), 100) + 2, 153);
-    const qint64 c0 = qDiv(x1 + 2, 12);
+    const qint64 x3 = qDiv<328718>(k3);
+    const qint64 k2 = 100 * qDiv<9>(qMod<328718>(k3)) + 99;
+    const qint64 k1 = qDiv<100>(qMod<36525>(k2)) * 5 + 2;
+    const qint64 x2 = qDiv<36525>(k2);
+    const qint64 x1 = qDiv<153>(5 * qDiv<100>(qMod<36525>(k2)) + 2);
+    const qint64 c0 = qDiv<12>(x1 + 2);
     const int y = 100 * x3 + x2 + c0;
     const int month = x1 - 12 * c0 + 3;
-    const int day = qDiv(qMod(k1, 153), 5) + 1;
+    const int day = qDiv<5>(qMod<153>(k1)) + 1;
     return QCalendar::YearMonthDay(y > 0 ? y : y - 1, month, day);
 }