| //===----------------------------------------------------------------------===// |
| // |
| // 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++98, c++03, c++11, c++14, c++17 |
| |
| // <chrono> |
| // class month; |
| |
| // constexpr month operator+(const month& x, const months& y) noexcept; |
| // Returns: month(int{x} + y.count()). |
| // |
| // constexpr month operator+(const months& x, const month& y) noexcept; |
| // Returns: |
| // month{modulo(static_cast<long long>(int{x}) + (y.count() - 1), 12) + 1} |
| // where modulo(n, 12) computes the remainder of n divided by 12 using Euclidean division. |
| // [Note: Given a divisor of 12, Euclidean division truncates towards negative infinity |
| // and always produces a remainder in the range of [0, 11]. |
| // Assuming no overflow in the signed summation, this operation results in a month |
| // holding a value in the range [1, 12] even if !x.ok(). —end note] |
| // [Example: February + months{11} == January. —end example] |
| |
| |
| |
| #include <chrono> |
| #include <type_traits> |
| #include <cassert> |
| |
| #include "test_macros.h" |
| |
| template <typename M, typename Ms> |
| constexpr bool testConstexpr() |
| { |
| M m{1}; |
| Ms offset{4}; |
| if (m + offset != M{5}) return false; |
| if (offset + m != M{5}) return false; |
| // Check the example |
| if (M{2} + Ms{11} != M{1}) return false; |
| return true; |
| } |
| |
| int main(int, char**) |
| { |
| using month = std::chrono::month; |
| using months = std::chrono::months; |
| |
| ASSERT_NOEXCEPT(std::declval<month>() + std::declval<months>()); |
| ASSERT_NOEXCEPT(std::declval<months>() + std::declval<month>()); |
| |
| ASSERT_SAME_TYPE(month, decltype(std::declval<month>() + std::declval<months>())); |
| ASSERT_SAME_TYPE(month, decltype(std::declval<months>() + std::declval<month>() )); |
| |
| static_assert(testConstexpr<month, months>(), ""); |
| |
| month my{2}; |
| for (unsigned i = 0; i <= 15; ++i) |
| { |
| month m1 = my + months{i}; |
| month m2 = months{i} + my; |
| assert(m1 == m2); |
| unsigned exp = i + 2; |
| while (exp > 12) |
| exp -= 12; |
| assert(static_cast<unsigned>(m1) == exp); |
| assert(static_cast<unsigned>(m2) == exp); |
| } |
| |
| return 0; |
| } |