64 lines · cpp
1//===----------------------------------------------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8// UNSUPPORTED: c++03, c++11, c++14, c++179 10// <chrono>11// class weekday;12 13// constexpr weekday operator+(const days& x, const weekday& y) noexcept;14// Returns: weekday(int{x} + y.count()).15//16// constexpr weekday operator+(const weekday& x, const days& y) noexcept;17// Returns:18// weekday{modulo(static_cast<long long>(unsigned{x}) + y.count(), 7)}19// where modulo(n, 7) computes the remainder of n divided by 7 using Euclidean division.20// [Note: Given a divisor of 12, Euclidean division truncates towards negative infinity21// and always produces a remainder in the range of [0, 6].22// Assuming no overflow in the signed summation, this operation results in a weekday23// holding a value in the range [0, 6] even if !x.ok(). -end note]24// [Example: Monday + days{6} == Sunday. -end example]25 26#include <chrono>27#include <cassert>28#include <type_traits>29#include <utility>30 31#include "test_macros.h"32#include "../../euclidian.h"33 34using weekday = std::chrono::weekday;35using days = std::chrono::days;36 37constexpr bool test() {38 for (unsigned i = 0; i <= 6; ++i)39 for (unsigned j = 0; j <= 6; ++j) {40 weekday wd1 = weekday{i} + days{j};41 weekday wd2 = days{j} + weekday{i};42 assert(wd1 == wd2);43 assert((wd1.c_encoding() == euclidian_addition<unsigned, 0, 6>(i, j)));44 assert((wd2.c_encoding() == euclidian_addition<unsigned, 0, 6>(i, j)));45 }46 47 // Check the example48 assert(weekday{1} + days{6} == weekday{0});49 return true;50}51 52int main(int, char**) {53 ASSERT_NOEXCEPT(std::declval<weekday>() + std::declval<days>());54 ASSERT_SAME_TYPE(weekday, decltype(std::declval<weekday>() + std::declval<days>()));55 56 ASSERT_NOEXCEPT(std::declval<days>() + std::declval<weekday>());57 ASSERT_SAME_TYPE(weekday, decltype(std::declval<days>() + std::declval<weekday>()));58 59 test();60 static_assert(test());61 62 return 0;63}64