xlnt/source/utils/date.cpp

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// Copyright (c) 2014-2020 Thomas Fussell
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, WRISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE
//
// @license: http://www.opensource.org/licenses/mit-license.php
// @author: see AUTHORS file
#include <cmath>
#include <ctime>
#include <xlnt/utils/date.hpp>
namespace {
std::tm safe_localtime(std::time_t raw_time)
{
#ifdef _MSC_VER
std::tm result;
localtime_s(&result, &raw_time);
return result;
#else
return *localtime(&raw_time);
#endif
}
} // namespace
namespace xlnt {
date::date(int year_, int month_, int day_)
: year(year_), month(month_), day(day_)
{
}
date date::from_number(int days_since_base_year, calendar base_date)
{
date result(0, 0, 0);
if (base_date == calendar::mac_1904)
{
days_since_base_year += 1462;
}
if (days_since_base_year == 60)
{
result.day = 29;
result.month = 2;
result.year = 1900;
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return result;
}
else if (days_since_base_year < 60)
{
days_since_base_year++;
}
int l = days_since_base_year + 68569 + 2415019;
int n = int((4 * l) / 146097);
l = l - int((146097 * n + 3) / 4);
int i = int((4000 * (l + 1)) / 1461001);
l = l - int((1461 * i) / 4) + 31;
int j = int((80 * l) / 2447);
result.day = l - int((2447 * j) / 80);
l = int(j / 11);
result.month = j + 2 - (12 * l);
result.year = 100 * (n - 49) + i + l;
return result;
}
bool date::operator==(const date &comparand) const
{
return year == comparand.year && month == comparand.month && day == comparand.day;
}
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bool date::operator!=(const date &comparand) const
{
return !(*this == comparand);
}
int date::to_number(calendar base_date) const
{
if (day == 29 && month == 2 && year == 1900)
{
return 60;
}
int days_since_1900 = int((1461 * (year + 4800 + int((month - 14) / 12))) / 4)
+ int((367 * (month - 2 - 12 * ((month - 14) / 12))) / 12)
- int((3 * (int((year + 4900 + int((month - 14) / 12)) / 100))) / 4) + day - 2415019 - 32075;
if (days_since_1900 <= 60)
{
days_since_1900--;
}
if (base_date == calendar::mac_1904)
{
return days_since_1900 - 1462;
}
return days_since_1900;
}
date date::today()
{
std::tm now = safe_localtime(std::time(nullptr));
return date(1900 + now.tm_year, now.tm_mon + 1, now.tm_mday);
}
int date::weekday() const
{
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std::tm tm{0};
tm.tm_mday = day;
tm.tm_mon = month - 1;
tm.tm_year = year - 1900;
std::time_t time = std::mktime(&tm);
return safe_localtime(time).tm_wday;
}
} // namespace xlnt