96 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 year_month_day;12 13// constexpr operator local_days() const noexcept;14//15// Returns: If ok(), returns a local_days holding a count of days from the16// local_days epoch to *this (a negative value if *this represents a date17// prior to the sys_days epoch). Otherwise, if y_.ok() && m_.ok() is true,18// returns a sys_days which is offset from sys_days{y_/m_/last} by the19// number of days d_ is offset from sys_days{y_/m_/last}.day(). Otherwise20// the value returned is unspecified.21//22// Remarks: A local_days in the range [days{-12687428}, days{11248737}] which23// is converted to a year_month_day shall have the same value when24// converted back to a sys_days.25//26// [Example:27// static_assert(year_month_day{local_days{2017y/January/0}} == 2016y/December/31);28// static_assert(year_month_day{local_days{2017y/January/31}} == 2017y/January/31);29// static_assert(year_month_day{local_days{2017y/January/32}} == 2017y/February/1);30// -end example]31 32#include <chrono>33#include <cassert>34#include <type_traits>35#include <utility>36 37#include "test_macros.h"38 39void RunTheExample()40{41 using namespace std::chrono;42 43 static_assert(year_month_day{local_days{year{2017}/January/0}} == year{2016}/December/31);44 static_assert(year_month_day{local_days{year{2017}/January/31}} == year{2017}/January/31);45 static_assert(year_month_day{local_days{year{2017}/January/32}} == year{2017}/February/1);46}47 48int main(int, char**)49{50 using year = std::chrono::year;51 using month = std::chrono::month;52 using day = std::chrono::day;53 using local_days = std::chrono::local_days;54 using days = std::chrono::days;55 using year_month_day = std::chrono::year_month_day;56 57 ASSERT_NOEXCEPT(local_days(std::declval<year_month_day>()));58 RunTheExample();59 60 {61 constexpr year_month_day ymd{year{1970}, month{1}, day{1}};62 constexpr local_days sd{ymd};63 64 static_assert( sd.time_since_epoch() == days{0}, "");65 static_assert( year_month_day{sd} == ymd, ""); // and back66 }67 68 {69 constexpr year_month_day ymd{year{2000}, month{2}, day{2}};70 constexpr local_days sd{ymd};71 72 static_assert( sd.time_since_epoch() == days{10957+32}, "");73 static_assert( year_month_day{sd} == ymd, ""); // and back74 }75 76 // There's one more leap day between 1/1/40 and 1/1/7077 // when compared to 1/1/70 -> 1/1/200078 {79 constexpr year_month_day ymd{year{1940}, month{1}, day{2}};80 constexpr local_days sd{ymd};81 82 static_assert( sd.time_since_epoch() == days{-10957}, "");83 static_assert( year_month_day{sd} == ymd, ""); // and back84 }85 86 {87 year_month_day ymd{year{1939}, month{11}, day{29}};88 local_days sd{ymd};89 90 assert( sd.time_since_epoch() == days{-(10957+34)});91 assert( year_month_day{sd} == ymd); // and back92 }93 94 return 0;95}96