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//===----------------------------------------------------------------------===//
//
// 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_day;
// constexpr operator sys_days() const noexcept;
//
// Returns: If ok(), returns a sys_days holding a count of days from the
// sys_days epoch to *this (a negative value if *this represents a date
// prior to the sys_days epoch). Otherwise, if y_.ok() && m_.ok() is true,
// returns a sys_days which is offset from sys_days{y_/m_/last} by the
// number of days d_ is offset from sys_days{y_/m_/last}.day(). Otherwise
// the value returned is unspecified.
//
// Remarks: A sys_days in the range [days{-12687428}, days{11248737}] which
// is converted to a year_month_day shall have the same value when
// converted back to a sys_days.
//
// [Example:
// static_assert(year_month_day{sys_days{2017y/January/0}} == 2016y/December/31);
// static_assert(year_month_day{sys_days{2017y/January/31}} == 2017y/January/31);
// static_assert(year_month_day{sys_days{2017y/January/32}} == 2017y/February/1);
// -end example]
#include <chrono>
#include <type_traits>
#include <cassert>
#include "test_macros.h"
void RunTheExample()
{
using namespace std::chrono;
static_assert(year_month_day{sys_days{year{2017}/January/0}} == year{2016}/December/31);
static_assert(year_month_day{sys_days{year{2017}/January/31}} == year{2017}/January/31);
static_assert(year_month_day{sys_days{year{2017}/January/32}} == year{2017}/February/1);
}
int main(int, char**)
{
using year = std::chrono::year;
using month = std::chrono::month;
using day = std::chrono::day;
using sys_days = std::chrono::sys_days;
using days = std::chrono::days;
using year_month_day = std::chrono::year_month_day;
ASSERT_NOEXCEPT(sys_days(std::declval<year_month_day>()));
RunTheExample();
{
constexpr year_month_day ymd{year{1970}, month{1}, day{1}};
constexpr sys_days sd{ymd};
static_assert( sd.time_since_epoch() == days{0}, "");
static_assert( year_month_day{sd} == ymd, ""); // and back
}
{
constexpr year_month_day ymd{year{2000}, month{2}, day{2}};
constexpr sys_days sd{ymd};
static_assert( sd.time_since_epoch() == days{10957+32}, "");
static_assert( year_month_day{sd} == ymd, ""); // and back
}
// There's one more leap day between 1/1/40 and 1/1/70
// when compared to 1/1/70 -> 1/1/2000
{
constexpr year_month_day ymd{year{1940}, month{1}, day{2}};
constexpr sys_days sd{ymd};
static_assert( sd.time_since_epoch() == days{-10957}, "");
static_assert( year_month_day{sd} == ymd, ""); // and back
}
{
year_month_day ymd{year{1939}, month{11}, day{29}};
sys_days sd{ymd};
assert( sd.time_since_epoch() == days{-(10957+34)});
assert( year_month_day{sd} == ymd); // and back
}
// These two tests check the wording for LWG 3206
{
constexpr year_month_day ymd{year{1971}, month{1}, day{0}}; // bad day
static_assert(!ymd.ok(), "");
static_assert( ymd.year().ok(), "");
static_assert( ymd.month().ok(), "");
static_assert(!ymd.day().ok(), "");
constexpr sys_days sd{ymd};
static_assert(sd.time_since_epoch() == days{364}, "");
static_assert(sd == sys_days{ymd.year()/ymd.month()/day{1}} + (ymd.day() - day{1}), "");
}
{
constexpr year_month_day ymd{year{1970}, month{12}, day{32}}; // bad day
static_assert(!ymd.ok(), "");
static_assert( ymd.year().ok(), "");
static_assert( ymd.month().ok(), "");
static_assert(!ymd.day().ok(), "");
constexpr sys_days sd{ymd};
static_assert(sd.time_since_epoch() == days{365}, "");
static_assert(sd == sys_days{ymd.year()/ymd.month()/day{1}} + (ymd.day() - day{1}), "");
}
return 0;
}
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