//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++03, c++11, c++14, c++17
// <chrono>
// class year_month;
// constexpr year_month operator-(const year_month& ym, const years& dy) noexcept;
// Returns: ym + -dy.
//
// constexpr year_month operator-(const year_month& ym, const months& dm) noexcept;
// Returns: ym + -dm.
//
// constexpr months operator-(const year_month& x, const year_month& y) noexcept;
// Returns: x.year() - y.year() + months{static_cast<int>(unsigned{x.month()}) -
// static_cast<int>(unsigned{y.month()})}
#include <chrono>
#include <cassert>
#include <type_traits>
#include <utility>
#include "test_macros.h"
using year = std::chrono::year;
using years = std::chrono::years;
using month = std::chrono::month;
using months = std::chrono::months;
using year_month = std::chrono::year_month;
constexpr bool test() {
{ // year_month - years
year_month ym{year{1234}, std::chrono::January};
for (int i = 0; i <= 10; ++i) {
year_month ym1 = ym - years{i};
assert(static_cast<int>(ym1.year()) == 1234 - i);
assert(ym1.month() == std::chrono::January);
}
}
{ // year_month - months
year_month ym{year{1234}, std::chrono::November};
for (int i = 0; i <= 10; ++i) {
year_month ym1 = ym - months{i};
assert(static_cast<int>(ym1.year()) == 1234);
assert(ym1.month() == month(11 - i));
}
// Test the year wraps around.
for (int i = 12; i <= 15; ++i) {
year_month ym1 = ym - months{i};
assert(static_cast<int>(ym1.year()) == 1233);
assert(ym1.month() == month(11 - i + 12));
}
}
{ // year_month - year_month
// Same year
year y{2345};
for (int i = 1; i <= 12; ++i)
for (int j = 1; j <= 12; ++j) {
months diff = year_month{y, month(i)} - year_month{y, month(j)};
assert(diff.count() == i - j);
}
// TODO: different year
}
return true;
}
int main(int, char**) {
// year_month - years
ASSERT_NOEXCEPT(std::declval<year_month>() - std::declval<years>());
ASSERT_SAME_TYPE(year_month, decltype(std::declval<year_month>() - std::declval<years>()));
// year_month - months
ASSERT_NOEXCEPT(std::declval<year_month>() - std::declval<months>());
ASSERT_SAME_TYPE(year_month, decltype(std::declval<year_month>() - std::declval<months>()));
// year_month - year_month
ASSERT_NOEXCEPT(std::declval<year_month>() - std::declval<year_month>());
ASSERT_SAME_TYPE(months, decltype(std::declval<year_month>() - std::declval<year_month>()));
test();
static_assert(test());
return 0;
}