| /**************************************************************************** |
| ** |
| ** 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 "qjuliancalendar_p.h" |
| #include "qromancalendar_data_p.h" |
| #include "qcalendarmath_p.h" |
| #include <QtCore/qmath.h> |
| #include <QtCore/qlocale.h> |
| #include <QtCore/qdatetime.h> |
| |
| QT_BEGIN_NAMESPACE |
| |
| using namespace QRoundingDown; |
| |
| /*! |
| \since 5.14 |
| |
| \class QJulianCalendar |
| \inmodule QtCore |
| \brief The QJulianCalendar class provides Julian calendar system |
| implementation. |
| |
| \section1 Julian Calendar |
| |
| The Julian calendar, proposed by Julius Caesar in 46 BC (708 AUC), was a |
| reform of the Roman calendar. It took effect on 1 January 45 BC (AUC 709), |
| by edict. It was the predominant calendar in the Roman world, most of |
| Europe, and in European settlements in the Americas and elsewhere, until it |
| was refined and gradually replaced by the Gregorian calendar, |
| promulgated in 1582 by Pope Gregory XIII. |
| |
| The Julian calendar gains against the mean tropical year at the rate of one |
| day in 128 years. For the Gregorian calendar, the figure is one day in |
| 3030 years. The difference in the average length of the year |
| between Julian (365.25 days) and Gregorian (365.2425 days) is 0.002%. |
| |
| Source: \l {https://en.wikipedia.org/wiki/Julian_calendar}{Wikipedia page on |
| Julian Calendar} |
| */ |
| |
| QJulianCalendar::QJulianCalendar() |
| : QRomanCalendar(QStringLiteral("Julian"), QCalendar::System::Julian) {} |
| |
| QString QJulianCalendar::name() const |
| { |
| return QStringLiteral("Julian"); |
| } |
| |
| QCalendar::System QJulianCalendar::calendarSystem() const |
| { |
| return QCalendar::System::Julian; |
| } |
| |
| bool QJulianCalendar::isLeapYear(int year) const |
| { |
| if (year == QCalendar::Unspecified || !year) |
| return false; |
| |
| return qMod(year < 0 ? year + 1 : year, 4) == 0; |
| } |
| |
| // Julian Day 0 was January the first in the proleptic Julian calendar's 4713 BC |
| |
| bool QJulianCalendar::dateToJulianDay(int year, int month, int day, qint64 *jd) const |
| { |
| Q_ASSERT(jd); |
| if (!isDateValid(year, month, day)) |
| return false; |
| 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); |
| *jd = j1 + j2 + day + 1721117; |
| return true; |
| } |
| |
| 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 int month = quint8(x1 - 12 * c0 + 3); |
| const int day = qDiv(qMod(k1, 153), 5) + 1; |
| return QCalendar::YearMonthDay(y > 0 ? y : y - 1, month, day); |
| } |
| |
| QT_END_NAMESPACE |