SFML/include/SFML/System/SuspendAwareClock.hpp
2024-09-11 16:02:01 -06:00

77 lines
2.9 KiB
C++

////////////////////////////////////////////////////////////
//
// SFML - Simple and Fast Multimedia Library
// Copyright (C) 2007-2024 Laurent Gomila (laurent@sfml-dev.org)
//
// 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.
//
////////////////////////////////////////////////////////////
#pragma once
////////////////////////////////////////////////////////////
// Headers
////////////////////////////////////////////////////////////
#include <SFML/System/Export.hpp>
#include <chrono>
namespace sf
{
////////////////////////////////////////////////////////////
/// \brief Android, chrono-compatible, suspend-aware clock
///
/// Linux steady clock is represented by `CLOCK_MONOTONIC`.
/// However, this implementation does not work properly for
/// long-running clocks that work in the background when the
/// system is suspended.
///
/// `SuspendAwareClock` uses `CLOCK_BOOTTIME` which is identical
/// to `CLOCK_MONOTONIC`, except that it also includes any time
/// that the system is suspended.
///
/// Note: In most cases, `CLOCK_MONOTONIC` is a better choice.
/// Make sure this implementation is required for your use case.
///
////////////////////////////////////////////////////////////
struct SFML_SYSTEM_API SuspendAwareClock
{
////////////////////////////////////////////////////////////
/// \brief Type traits and static members
///
/// These type traits and static members meet the requirements
/// of a Clock concept in the C++ Standard. More specifically,
/// TrivialClock requirements are met. Thus, naming convention
/// has been kept consistent to allow for extended use e.g.
/// https://en.cppreference.com/w/cpp/chrono/is_clock
///
////////////////////////////////////////////////////////////
using duration = std::chrono::nanoseconds;
using rep = duration::rep;
using period = duration::period;
using time_point = std::chrono::time_point<SuspendAwareClock, duration>;
static constexpr bool is_steady = true; // NOLINT(readability-identifier-naming)
static time_point now() noexcept;
};
} // namespace sf