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Diffstat (limited to 'src/corelib/time/qislamiccivilcalendar.cpp')
-rw-r--r-- | src/corelib/time/qislamiccivilcalendar.cpp | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/src/corelib/time/qislamiccivilcalendar.cpp b/src/corelib/time/qislamiccivilcalendar.cpp new file mode 100644 index 0000000000..27c93f5c00 --- /dev/null +++ b/src/corelib/time/qislamiccivilcalendar.cpp @@ -0,0 +1,125 @@ +/**************************************************************************** +** +** Copyright (C) 2018 The Qt Company Ltd. +** Contact: https://www.qt.io/licensing/ +** +** This file is part of the QtCore module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** Commercial License Usage +** Licensees holding valid commercial Qt licenses may use this file in +** accordance with the commercial license agreement provided with the +** Software or, alternatively, in accordance with the terms contained in +** a written agreement between you and The Qt Company. For licensing terms +** and conditions see https://www.qt.io/terms-conditions. For further +** information use the contact form at https://www.qt.io/contact-us. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 3 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL3 included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 3 requirements +** will be met: https://www.gnu.org/licenses/lgpl-3.0.html. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 2.0 or (at your option) the GNU General +** Public license version 3 or any later version approved by the KDE Free +** Qt Foundation. The licenses are as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3 +** included in the packaging of this file. Please review the following +** information to ensure the GNU General Public License requirements will +** be met: https://www.gnu.org/licenses/gpl-2.0.html and +** https://www.gnu.org/licenses/gpl-3.0.html. +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "qglobal.h" +#include "qislamiccivilcalendar_p.h" +#include "qcalendarmath_p.h" +#include <QtCore/qmath.h> + +QT_BEGIN_NAMESPACE + +using namespace QRoundingDown; + +/*! + \since 5.14 + + \class QIslamicCivilCalendar + \inmodule QtCore + \brief Implements a commonly-used computed version of the Islamic calendar. + + \section1 Civil Islamic Calendar + + QIslamicCivilCalendar implements a tabular version of the Hijri calendar which + is known as the Islamic Civil Calendar. It has the same numbering of years and + months, but the months are determined by arithmetical rules rather than by + observation or astronomical calculations. + + \section2 Calendar Organization + + The civil calendar follows the usual tabular scheme of odd-numbered months and + the last month of each leap year being 30 days long, the rest being 29 days + long. Its determination of leap years follows a 30-year cycle, in each of + which the years 2, 5, 7, 10, 13, 16, 18, 21, 24, 26 and 29 are leap years. + + \sa QJijriCalendar, QCalendar +*/ + +QIslamicCivilCalendar::QIslamicCivilCalendar() + : QHijriCalendar(QStringLiteral("Islamic Civil"), QCalendar::System::IslamicCivil) +{ + registerAlias(QStringLiteral("islamic-civil")); // CLDR name + registerAlias(QStringLiteral("islamicc")); // old CLDR name, still (2018) used by Mozilla + // Until we have a oncrete implementation that knows all the needed ephemerides: + registerAlias(QStringLiteral("Islamic")); +} + +QString QIslamicCivilCalendar::name() const +{ + return QStringLiteral("Islamic Civil"); +} + +QCalendar::System QIslamicCivilCalendar::calendarSystem() const +{ + return QCalendar::System::IslamicCivil; +} + +bool QIslamicCivilCalendar::isLeapYear(int year) const +{ + if (year == QCalendar::Unspecified) + return false; + if (year < 0) + ++year; + return qMod(year * 11 + 14, 30) < 11; +} + +bool QIslamicCivilCalendar::dateToJulianDay(int year, int month, int day, qint64 *jd) const +{ + Q_ASSERT(jd); + if (!isDateValid(year, month, day)) + return false; + if (year <= 0) + ++year; + *jd = qDiv(10631 * year - 10617, 30) + + qDiv(325 * month - 320, 11) + + day + 1948439; + return true; +} + +QCalendar::YearMonthDay QIslamicCivilCalendar::julianDayToDate(qint64 jd) const +{ + const 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; + return QCalendar::YearMonthDay(y > 0 ? y : y - 1, month, day); +} + +QT_END_NAMESPACE |