Time.h

/*
 * Gamedev Framework (gf)
 * Copyright (C) 2016-2017 Julien Bernard
 *
 * This software is provided 'as-is', without any express or implied
 * warranty.  In no event will the authors be held liable for any damages
 * arising from the use of this software.
 *
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 *
 * 1. The origin of this software must not be misrepresented; you must not
 *    claim that you wrote the original software. If you use this software
 *    in a product, an acknowledgment in the product documentation would be
 *    appreciated but is not required.
 * 2. Altered source versions must be plainly marked as such, and must not be
 *    misrepresented as being the original software.
 * 3. This notice may not be removed or altered from any source distribution.
 *
 * Part of this file comes from SFML, with the same license:
 * Copyright (C) 2007-2015 Laurent Gomila (laurent@sfml-dev.org)
 */
#ifndef GF_TIME_H
#define GF_TIME_H

#include <cstdint>
#include <chrono>
#include <ratio>

#include "Portability.h"

namespace gf {
#ifndef DOXYGEN_SHOULD_SKIP_THIS
inline namespace v1 {
#endif

  class GF_API Time {
  public:
    constexpr Time()
    : m_duration(std::chrono::steady_clock::duration::zero())
    {

    }

    constexpr explicit Time(std::chrono::steady_clock::duration duration)
    : m_duration(duration)
    {

    }

    constexpr float asSeconds() const {
      return std::chrono::duration_cast<std::chrono::duration<float>>(m_duration).count();
    }

    constexpr int32_t asMilliseconds() const {
      return std::chrono::duration_cast<std::chrono::duration<int32_t, std::milli>>(m_duration).count();
    }

    constexpr int64_t asMicroseconds() const {
      return std::chrono::duration_cast<std::chrono::duration<int64_t, std::micro>>(m_duration).count();
    }

    constexpr std::chrono::steady_clock::duration asDuration() const {
      return m_duration;
    }

    Time& addTo(Time other) {
      m_duration += other.m_duration;
      return *this;
    }

    Time& subTo(Time other) {
      m_duration -= other.m_duration;
      return *this;
    }

    static const Time Zero;

    static constexpr Time zero() {
      return Time();
    }

  private:
    std::chrono::steady_clock::duration m_duration;
  };

  constexpr
  Time seconds(float amount) {
    return Time(std::chrono::duration_cast<std::chrono::steady_clock::duration>(std::chrono::duration<float>(amount)));
  }

  constexpr
  Time milliseconds(int32_t amount) {
    return Time(std::chrono::duration_cast<std::chrono::steady_clock::duration>(std::chrono::duration<int32_t, std::milli>(amount)));
  }

  constexpr
  Time microseconds(int64_t amount) {
    return Time(std::chrono::duration_cast<std::chrono::steady_clock::duration>(std::chrono::duration<int64_t, std::micro>(amount)));
  }

  constexpr
  bool operator==(Time rhs, Time lhs) {
    return rhs.asDuration() == lhs.asDuration();
  }

  constexpr
  bool operator!=(Time rhs, Time lhs) {
    return rhs.asDuration() != lhs.asDuration();
  }

  constexpr
  bool operator<(Time rhs, Time lhs) {
    return rhs.asDuration() < lhs.asDuration();
  }

  constexpr
  bool operator>(Time rhs, Time lhs) {
    return rhs.asDuration() > lhs.asDuration();
  }

  constexpr
  bool operator<=(Time rhs, Time lhs) {
    return rhs.asDuration() <= lhs.asDuration();
  }

  constexpr
  bool operator>=(Time rhs, Time lhs) {
    return rhs.asDuration() >= lhs.asDuration();
  }

  constexpr
  Time operator+(Time rhs, Time lhs) {
    return Time(rhs.asDuration() + lhs.asDuration());
  }

  inline
  Time operator+=(Time& rhs, Time lhs) {
    return rhs.addTo(lhs);
  }

  constexpr
  Time operator-(Time rhs, Time lhs) {
    return Time(rhs.asDuration() - lhs.asDuration());
  }

  inline
  Time operator-=(Time& rhs, Time lhs) {
    return rhs.subTo(lhs);
  }

#ifndef DOXYGEN_SHOULD_SKIP_THIS
}
#endif
}

#endif // GF_TIME_H