time.hpp

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/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
/*
 * Copyright (c) 2013-2021 Regents of the University of California.
 *
 * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
 *
 * ndn-cxx library is free software: you can redistribute it and/or modify it under the
 * terms of the GNU Lesser General Public License as published by the Free Software
 * Foundation, either version 3 of the License, or (at your option) any later version.
 *
 * ndn-cxx library is distributed in the hope that it will be useful, but WITHOUT ANY
 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
 * PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.
 *
 * You should have received copies of the GNU General Public License and GNU Lesser
 * General Public License along with ndn-cxx, e.g., in COPYING.md file.  If not, see
 * <http://www.gnu.org/licenses/>.
 *
 * See AUTHORS.md for complete list of ndn-cxx authors and contributors.
 */

#ifndef NDN_CXX_UTIL_TIME_HPP
#define NDN_CXX_UTIL_TIME_HPP

#include "ndn-cxx/detail/common.hpp"

#include <boost/asio/wait_traits.hpp>
#include <boost/chrono.hpp>

namespace ndn {
namespace time {

template<typename Rep, typename Period>
using duration = boost::chrono::duration<Rep, Period>;

using boost::chrono::duration_cast;

// C++20
using days   = duration<int_fast32_t, boost::ratio<86400>>;
using weeks  = duration<int_fast32_t, boost::ratio<604800>>;
using months = duration<int_fast32_t, boost::ratio<2629746>>;
using years  = duration<int_fast32_t, boost::ratio<31556952>>;

// C++11
using hours        = boost::chrono::hours;
using minutes      = boost::chrono::minutes;
using seconds      = boost::chrono::seconds;
using milliseconds = boost::chrono::milliseconds;
using microseconds = boost::chrono::microseconds;
using nanoseconds  = boost::chrono::nanoseconds;

template<typename Rep, typename Period, typename = std::enable_if_t<std::numeric_limits<Rep>::is_signed>>
constexpr duration<Rep, Period>
abs(duration<Rep, Period> d)
{
  return d >= d.zero() ? d : -d;
}

} // namespace time

inline namespace literals {
inline namespace time_literals {

constexpr time::days
operator "" _day(unsigned long long days)
{
  return time::days{days};
}

constexpr time::duration<long double, time::days::period>
operator "" _day(long double days)
{
  return time::duration<long double, time::days::period>{days};
}

constexpr time::days
operator "" _days(unsigned long long days)
{
  return time::days{days};
}

constexpr time::duration<long double, time::days::period>
operator "" _days(long double days)
{
  return time::duration<long double, time::days::period>{days};
}

constexpr time::hours
operator "" _h(unsigned long long hrs)
{
  return time::hours{hrs};
}

constexpr time::duration<long double, time::hours::period>
operator "" _h(long double hrs)
{
  return time::duration<long double, time::hours::period>{hrs};
}

constexpr time::minutes
operator "" _min(unsigned long long mins)
{
  return time::minutes{mins};
}

constexpr time::duration<long double, time::minutes::period>
operator "" _min(long double mins)
{
  return time::duration<long double, time::minutes::period>{mins};
}

constexpr time::seconds
operator "" _s(unsigned long long secs)
{
  return time::seconds{secs};
}

constexpr time::duration<long double, time::seconds::period>
operator "" _s(long double secs)
{
  return time::duration<long double, time::seconds::period>{secs};
}

constexpr time::milliseconds
operator "" _ms(unsigned long long msecs)
{
  return time::milliseconds{msecs};
}

constexpr time::duration<long double, time::milliseconds::period>
operator "" _ms(long double msecs)
{
  return time::duration<long double, time::milliseconds::period>{msecs};
}

constexpr time::microseconds
operator "" _us(unsigned long long usecs)
{
  return time::microseconds{usecs};
}

constexpr time::duration<long double, time::microseconds::period>
operator "" _us(long double usecs)
{
  return time::duration<long double, time::microseconds::period>{usecs};
}

constexpr time::nanoseconds
operator "" _ns(unsigned long long nsecs)
{
  return time::nanoseconds{nsecs};
}

constexpr time::duration<long double, time::nanoseconds::period>
operator "" _ns(long double nsecs)
{
  return time::duration<long double, time::nanoseconds::period>{nsecs};
}

} // inline namespace time_literals
} // inline namespace literals

namespace time {

using namespace literals::time_literals;

class system_clock
{
public:
  using duration   = boost::chrono::system_clock::duration;
  using rep        = duration::rep;
  using period     = duration::period;
  using time_point = boost::chrono::time_point<system_clock>;
  static constexpr bool is_steady = boost::chrono::system_clock::is_steady;

  using TimePoint = time_point;
  using Duration = duration;

  static time_point
  now() noexcept;

  static std::time_t
  to_time_t(const time_point& t) noexcept;

  static time_point
  from_time_t(std::time_t t) noexcept;
};

class steady_clock
{
public:
  using duration   = boost::chrono::steady_clock::duration;
  using rep        = duration::rep;
  using period     = duration::period;
  using time_point = boost::chrono::time_point<steady_clock>;
  static constexpr bool is_steady = true;

  using TimePoint = time_point;
  using Duration = duration;

  static time_point
  now() noexcept;

private:
  static duration
  to_wait_duration(duration d);

  friend struct boost::asio::wait_traits<steady_clock>; // see steady-timer.hpp
};

const system_clock::time_point&
getUnixEpoch();

milliseconds
toUnixTimestamp(const system_clock::time_point& point);

system_clock::time_point
fromUnixTimestamp(milliseconds duration);

std::string
toIsoString(const system_clock::time_point& timePoint);

system_clock::time_point
fromIsoString(const std::string& isoString);

std::string
toIsoExtendedString(const system_clock::time_point& timePoint);

system_clock::time_point
fromIsoExtendedString(const std::string& isoString);

std::string
toString(const system_clock::time_point& timePoint,
         const std::string& format = "%Y-%m-%d %H:%M:%S",
         const std::locale& locale = std::locale("C"));

system_clock::time_point
fromString(const std::string& timePointStr,
           const std::string& format = "%Y-%m-%d %H:%M:%S",
           const std::locale& locale = std::locale("C"));

} // namespace time
} // namespace ndn

namespace boost {
namespace chrono {

template<typename CharT>
struct clock_string<ndn::time::system_clock, CharT>
{
  static std::basic_string<CharT>
  since();
};

template<typename CharT>
struct clock_string<ndn::time::steady_clock, CharT>
{
  static std::basic_string<CharT>
  since();
};

extern template struct clock_string<ndn::time::system_clock, char>;
extern template struct clock_string<ndn::time::steady_clock, char>;

} // namespace chrono
} // namespace boost

#endif // NDN_CXX_UTIL_TIME_HPP