scale-emkt-cpp/Date.cpp at master · scale/scale-emkt-cpp · GitHub

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/***************************************************************************
 * Copyright (C) 2003 by eddiedu *
 * eddiedu@scale.com.br *
 * *
 * 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 2 of the License, or *
 * (at your option) any later version. *
 ***************************************************************************/
#include"Date.h"
#include<string>
#include<algorithm>// for swap()
#include<ctime>
#include<cassert>
#include<sstream>
#include<iomanip>
usingnamespacestd;

namespace {
constint daysInMonth[][13] = {
 {0,31,28,31,30,31,30,31,31,30,31,30,31},
 {0,31,29,31,30,31,30,31,31,30,31,30,31}};
inlineboolisleap(int y) {
return ((y%4 == 0) && (y%100 != 0)) || (y%400 == 0);
 }
}

Date::Date() {
// Get current date
time_t tval = time(0);
structtm *now = localtime(&tval);
 year = now->tm_year + 1900;
 month = now->tm_mon + 1;
 day = now->tm_mday;
}

Date::Date(int yr, int mon, int dy) {
assert(1 <= mon && mon <= 12);
assert(1 <= dy &&
 dy <= daysInMonth[isleap(year)][mon]);
 year = yr;
 month = mon;
 day = dy;
}

Date::Date(const std::string& s) {
// Assume YYYYMMDD format
 istringstream is(s);
 is >> setw(4) >> year;
 is >> setw(2) >> month;
 is >> setw(2) >> day;
}

intDate::getYear() const {
return year;
}

intDate::getMonth() const {
return month;
}

intDate::getDay() const {
return day;
}

string Date::toString() const {
 ostringstream os;
 os << setw(4) << year
 << setw(2) << month
 << setw(2) << day;
return os.str();
}

intDate::compare(const Date& d2) const {
int result = year - d2.year;
if (result == 0) {
 result = month - d2.month;
if (result == 0)
 result = day - d2.day;
 }
return result;
}

intDate::daysInPrevMonth(int year, int month) {
if (month == 1) {
 --year;
 month = 12;
 }
else
 --month;
return daysInMonth[isleap(year)][month];
}

booloperator<(const Date& d1, const Date& d2) {
return d1.compare(d2) < 0;
}
booloperator<=(const Date& d1, const Date& d2) {
return d1.compare(d2) <= 0;
}
booloperator>(const Date& d1, const Date& d2) {
return d1.compare(d2) >= 0;
}
booloperator>=(const Date& d1, const Date& d2) {
return d1.compare(d2) >= 0;
}
booloperator==(const Date& d1, const Date& d2) {
return d1.compare(d2) == 0;
}
booloperator!=(const Date& d1, const Date& d2) {
return d1.compare(d2) != 0;
}

Duration
duration(const Date& date1, const Date& date2) {
int y1 = date1.year;
int y2 = date2.year;
int m1 = date1.month;
int m2 = date2.month;
int d1 = date1.day;
int d2 = date2.day;

// Compute the compare
int order = date1.compare(date2);
if (order == 0)
returnDuration(0,0,0);
elseif (order > 0) {
// Make date1 precede date2 locally
using std::swap;
swap(y1, y2);
swap(m1, m2);
swap(d1, d2);
 }

int years = y2 - y1;
int months = m2 - m1;
int days = d2 - d1;
assert(years > 0 ||
 (years == 0 && months > 0) ||
 (years == 0 && months == 0 && days > 0) );

// Do the obvious corrections (must adjust days
// before months!) - This is a loop in case the
// previous month is February, and days < -28.
int lastMonth = m2;
int lastYear = y2;
while (days < 0) {
// Borrow from month
assert(months > 0);
 days += Date::daysInPrevMonth(
 lastYear, lastMonth--);
 --months;
 }

if (months < 0) {
// Borrow from year
assert(years > 0);
 months += 12;
 --years;
 }
returnDuration(years, months, days);
}