1 //===----------------------------------------------------------------------===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is dual licensed under the MIT and the University of Illinois Open 6 // Source Licenses. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 // UNSUPPORTED: c++98, c++03, c++11, c++14, c++17 10 11 // <chrono> 12 // class weekday; 13 14 // constexpr weekday operator+(const days& x, const weekday& y) noexcept; 15 // Returns: weekday(int{x} + y.count()). 16 // 17 // constexpr weekday operator+(const weekday& x, const days& y) noexcept; 18 // Returns: 19 // weekday{modulo(static_cast<long long>(unsigned{x}) + y.count(), 7)} 20 // where modulo(n, 7) computes the remainder of n divided by 7 using Euclidean division. 21 // [Note: Given a divisor of 12, Euclidean division truncates towards negative infinity 22 // and always produces a remainder in the range of [0, 6]. 23 // Assuming no overflow in the signed summation, this operation results in a weekday 24 // holding a value in the range [0, 6] even if !x.ok(). end note] 25 // [Example: Monday + days{6} == Sunday. end example] 26 27 28 29 #include <chrono> 30 #include <type_traits> 31 #include <cassert> 32 33 #include "test_macros.h" 34 #include "../../euclidian.h" 35 36 template <typename M, typename Ms> 37 constexpr bool testConstexpr() 38 { 39 M m{1}; 40 Ms offset{4}; 41 if (m + offset != M{5}) return false; 42 if (offset + m != M{5}) return false; 43 // Check the example 44 if (M{1} + Ms{6} != M{0}) return false; 45 return true; 46 } 47 48 int main() 49 { 50 using weekday = std::chrono::weekday; 51 using days = std::chrono::days; 52 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 static_assert(testConstexpr<weekday, days>(), ""); 60 61 for (unsigned i = 0; i <= 6; ++i) 62 for (unsigned j = 0; j <= 6; ++j) 63 { 64 weekday wd1 = weekday{i} + days{j}; 65 weekday wd2 = days{j} + weekday{i}; 66 assert(wd1 == wd2); 67 assert((static_cast<unsigned>(wd1) == euclidian_addition<unsigned, 0, 6>(i, j))); 68 assert((static_cast<unsigned>(wd2) == euclidian_addition<unsigned, 0, 6>(i, j))); 69 } 70 } 71
