//
// VMime library (http://www.vmime.org)
// Copyright (C) 2002 Vincent Richard <vincent@vmime.org>
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 3 of
// the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// General Public License for more details.
//
// You should have received a copy of the GNU General Public License along
// with this program; if not, write to the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
//
// Linking this library statically or dynamically with other modules is making
// a combined work based on this library. Thus, the terms and conditions of
// the GNU General Public License cover the whole combination.
//
#include "vmime/utility/datetimeUtils.hpp"
#include <stdexcept>
namespace vmime {
namespace utility {
#ifndef VMIME_BUILDING_DOC
static inline void nextMonth(datetime& d) {
if (d.getMonth() >= 12) {
d.setMonth(1);
d.setYear(d.getYear() + 1);
} else {
d.setMonth(d.getMonth() + 1);
}
}
static inline void prevMonth(datetime& d) {
if (d.getMonth() <= 1) {
d.setYear(d.getYear() - 1);
d.setMonth(12);
} else {
d.setMonth(d.getMonth() - 1);
}
}
static inline void nextDay(datetime& d) {
if (d.getDay() >= datetimeUtils::getDaysInMonth(d.getYear(), d.getMonth())) {
d.setDay(1);
nextMonth(d);
} else {
d.setDay(d.getDay() + 1);
}
}
static inline void prevDay(datetime& d) {
if (d.getDay() <= 1) {
prevMonth(d);
d.setDay(datetimeUtils::getDaysInMonth(d.getYear(), d.getMonth()));
} else {
d.setDay(d.getDay() - 1);
}
}
static inline void nextHour(datetime& d) {
if (d.getHour() >= 23) {
d.setHour(0);
nextDay(d);
} else {
d.setHour(d.getHour() + 1);
}
}
static inline void prevHour(datetime& d) {
if (d.getHour() <= 0) {
d.setHour(23);
prevDay(d);
} else {
d.setHour(d.getHour() - 1);
}
}
static inline void addHoursAndMinutes(datetime& d, const int h, const int m) {
d.setMinute(d.getMinute() + m);
if (d.getMinute() >= 60) {
d.setMinute(d.getMinute() - 60);
nextHour(d);
}
d.setHour(d.getHour() + h);
if (d.getHour() >= 24) {
d.setHour(d.getHour() - 24);
nextDay(d);
}
}
static inline void substractHoursAndMinutes(datetime& d, const int h, const int m) {
if (m > d.getMinute()) {
d.setMinute(60 - (m - d.getMinute()));
prevHour(d);
} else {
d.setMinute(d.getMinute() - m);
}
if (h > d.getHour()) {
d.setHour(24 - (h - d.getHour()));
prevDay(d);
} else {
d.setHour(d.getHour() - h);
}
}
#endif // VMIME_BUILDING_DOC
const datetime datetimeUtils::toUniversalTime(const datetime& date) {
if (date.getZone() == datetime::GMT) {
return date; // no conversion needed
}
datetime nd(date);
nd.setZone(datetime::GMT);
const int z = date.getZone();
const int h = (z < 0) ? (-z / 60) : (z / 60);
const int m = (z < 0) ? (-z - h * 60) : (z - h * 60);
if (z < 0) { // GMT-hhmm: add hours and minutes to date
addHoursAndMinutes(nd, h, m);
} else { // GMT+hhmm: substract hours and minutes from date
substractHoursAndMinutes(nd, h, m);
}
return nd;
}
const datetime datetimeUtils::toLocalTime(const datetime& date, const int zone) {
datetime utcDate(date);
if (utcDate.getZone() != datetime::GMT) {
utcDate = toUniversalTime(date); // convert to UT before
}
datetime nd(utcDate);
nd.setZone(zone);
const int h = (zone < 0) ? (-zone / 60) : (zone / 60);
const int m = (zone < 0) ? (-zone - h * 60) : (zone - h * 60);
if (zone < 0) { // GMT+hhmm: substract hours and minutes from date
substractHoursAndMinutes(nd, h, m);
} else { // GMT-hhmm: add hours and minutes to date
addHoursAndMinutes(nd, h, m);
}
return nd;
}
bool datetimeUtils::isLeapYear(const int year) {
// From RFC 3339 - Appendix C. Leap Years:
return ((year % 4) == 0 && (year % 100 != 0 || year % 400 == 0));
}
int datetimeUtils::getDaysInMonth(const int year, const int month) {
static const int daysInMonth[12] = {
31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};
static const int daysInMonthLeapYear[12] = {
31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};
if (month < 1 || month > 12) {
throw std::out_of_range("Invalid month number");
}
return isLeapYear(year) ? daysInMonthLeapYear[month - 1] : daysInMonth[month - 1];
}
int datetimeUtils::getDayOfWeek(const int year, const int month, const int day) {
int y = year;
int m = month;
if (month < 1 || month > 12) {
throw std::out_of_range("Invalid month number");
} else if (day < 1 || day > getDaysInMonth(year, month)) {
throw std::out_of_range("Invalid day number");
}
// From RFC-3339 - Appendix B. Day of the Week
// Adjust months so February is the last one
m -= 2;
if (m < 1) {
m += 12;
--y;
}
// Split by century
const int cent = y / 100;
y %= 100;
return ((26 * m - 2) / 10 + day + y + (y >> 2) + (cent >> 2) + 5 * cent) % 7;
}
int datetimeUtils::getWeekOfYear(const int year, const int month, const int day, const bool iso) {
// Algorithm from http://personal.ecu.edu/mccartyr/ISOwdALG.txt
const bool leapYear = ((year % 4) == 0 && (year % 100) != 0) || (year % 400) == 0;
const bool leapYear_1 = (((year - 1) % 4) == 0 && ((year - 1) % 100) != 0) || ((year - 1) % 400) == 0;
// 4. Find the DayOfYearNumber for Y M D
static const int DAY_OF_YEAR_NUMBER_MAP[12] = {
0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334
};
int DayOfYearNumber = day + DAY_OF_YEAR_NUMBER_MAP[month - 1];
if (leapYear && month > 2) {
DayOfYearNumber += 1;
}
// 5. Find the Jan1Weekday for Y (Monday=1, Sunday=7)
const int YY = (year - 1) % 100;
const int C = (year - 1) - YY;
const int G = YY + YY / 4;
const int Jan1Weekday = 1 + (((((C / 100) % 4) * 5) + G) % 7);
// 6. Find the Weekday for Y M D
const int H = DayOfYearNumber + (Jan1Weekday - 1);
const int Weekday = 1 + ((H - 1) % 7);
// 7. Find if Y M D falls in YearNumber Y-1, WeekNumber 52 or 53
int YearNumber = 0, WeekNumber = 0;
if (DayOfYearNumber <= (8 - Jan1Weekday) && Jan1Weekday > 4) {
YearNumber = year - 1;
if (Jan1Weekday == 5 || (Jan1Weekday == 6 && leapYear_1)) {
WeekNumber = 53;
} else {
WeekNumber = 52;
}
} else {
YearNumber = year;
}
// 8. Find if Y M D falls in YearNumber Y+1, WeekNumber 1
if (YearNumber == year) {
const int I = (leapYear ? 366 : 365);
if ((I - DayOfYearNumber) < (4 - Weekday)) {
YearNumber = year + 1;
WeekNumber = 1;
}
}
// 9. Find if Y M D falls in YearNumber Y, WeekNumber 1 through 53
if (YearNumber == year) {
const int J = DayOfYearNumber + (7 - Weekday) + (Jan1Weekday - 1);
WeekNumber = J / 7;
if (Jan1Weekday > 4) {
WeekNumber -= 1;
}
}
if (!iso && (WeekNumber == 1 && month == 12)) {
WeekNumber = 53;
}
return WeekNumber;
}
} // utility
} // vmime
