time.h

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#ifndef ZTH_TIME_H
#define ZTH_TIME_H
/*
 * Zth (libzth), a cooperative userspace multitasking library.
 * Copyright (C) 2019-2022  Jochem Rutgers
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */
 
#ifdef __cplusplus
 
#       include <libzth/allocator.h>
#       include <libzth/config.h>
#       include <libzth/util.h>
 
#       include <algorithm>
#       include <cmath>
#       include <cstdio>
#       include <ctime>
#       include <inttypes.h>
#       include <limits>
 
#       if defined(ZTH_OS_MAC) || defined(ZTH_OS_BAREMETAL)
#               ifdef ZTH_CUSTOM_CLOCK_GETTIME
extern "C" int clock_gettime(int clk_id, struct timespec* res);
#               endif
extern "C" int
clock_nanosleep(int clk_id, int flags, struct timespec const* request, struct timespec* remain);
#               ifndef CLOCK_MONOTONIC
#                       define CLOCK_MONOTONIC 1
#               endif
#               ifndef TIMER_ABSTIME
#                       define TIMER_ABSTIME 1
#               endif
#       endif
 
namespace zth {
 
class Timestamp;
 
class TimeInterval {
        ZTH_CLASS_NEW_DELETE(TimeInterval)
private:
        // Do not convert automatically.
        TimeInterval(Timestamp const&);
 
public:
        static long const BILLION = 1000000000L;
 
        constexpr static TimeInterval infinity() noexcept
        {
                return TimeInterval(std::numeric_limits<time_t>::max());
        }
 
        constexpr static TimeInterval null() noexcept
        {
                return TimeInterval();
        }
 
        constexpr TimeInterval() noexcept
                : m_t()
                , m_negative()
        {}
 
#       if __cplusplus >= 201103L
        // cppcheck-suppress noExplicitConstructor
        constexpr TimeInterval(time_t s, long ns = 0, bool negative = false) noexcept
                : m_t{s, ns}
                , m_negative{negative}
        {}
#       else
        // cppcheck-suppress noExplicitConstructor
        TimeInterval(time_t s, long ns = 0, bool negative = false) noexcept
                : m_t()
                , m_negative(negative)
        {
                m_t.tv_sec = s;
                m_t.tv_nsec = ns;
                zth_assert(isNormal());
        }
#       endif
 
        // cppcheck-suppress noExplicitConstructor
        constexpr TimeInterval(struct timespec const& ts) noexcept
                : m_t(ts)
                , m_negative()
        {}
 
        TimeInterval& operator=(TimeInterval const& t) noexcept
        {
                m_t = t.m_t;
                m_negative = t.m_negative;
                return *this;
        }
 
        constexpr TimeInterval(TimeInterval const& t) noexcept
                : m_t(t.ts())
                , m_negative(t.isNegative())
        {}
 
        // cppcheck-suppress noExplicitConstructor
        TimeInterval(float dt)
                : m_t()
                , m_negative()
        {
                init_float<float>(dt);
        }
 
        // cppcheck-suppress noExplicitConstructor
        TimeInterval(double dt)
                : m_t()
                , m_negative()
        {
                init_float<double>(dt);
        }
 
        // cppcheck-suppress noExplicitConstructor
        TimeInterval(long double dt)
                : m_t()
                , m_negative()
        {
                init_float<long double>(dt);
        }
 
        template <typename T>
        // cppcheck-suppress noExplicitConstructor
        constexpr14 TimeInterval(T dt) noexcept
                : m_t()
                , m_negative()
        {
                init_int<T>(dt);
        }
 
        template <typename T>
        static constexpr14 TimeInterval from_s(T s)
        {
                if(s > std::numeric_limits<time_t>::max())
                        return TimeInterval(std::numeric_limits<time_t>::max(), 999999999L);
 
                return TimeInterval(s);
        }
 
        template <typename T>
        static constexpr14 TimeInterval from_ms(T ms)
        {
                T s_ = ms / (T)1000;
                if((unsigned long long)s_ > (unsigned long long)std::numeric_limits<time_t>::max())
                        return TimeInterval(std::numeric_limits<time_t>::max(), 999999999L);
 
                return TimeInterval((time_t)s_, ((long)ms % 1000L) * 1000000L);
        }
 
        template <typename T>
        static constexpr14 TimeInterval from_us(T us)
        {
                T s_ = us / (T)1000000;
                if((unsigned long long)s_ > (unsigned long long)std::numeric_limits<time_t>::max())
                        return TimeInterval(std::numeric_limits<time_t>::max(), 999999999L);
 
                return TimeInterval((time_t)s_, ((long)us % 1000000L) * 1000L);
        }
 
        template <typename T>
        static constexpr14 TimeInterval from_ns(T ns)
        {
                T s_ = ns / (T)1000000000L;
                if(s_ > std::numeric_limits<time_t>::max())
                        return TimeInterval(std::numeric_limits<time_t>::max(), 999999999L);
 
                return TimeInterval((time_t)s_, (long)ns % 1000000000L);
        }
 
private:
        template <typename T>
        void init_float(T dt)
        {
                zth_assert(dt == dt); // Should not be NaN
 
                m_negative = dt < 0;
 
                if(std::fabs(dt) > (T)(std::numeric_limits<time_t>::max() / 2 - 1))
                        m_t.tv_sec = std::numeric_limits<time_t>::max();
                else
                        m_t.tv_sec = (time_t)std::fabs(dt);
                m_t.tv_nsec = (long)(std::fmod(std::fabs(dt), (T)1.0) * (T)1e9);
 
                if(m_t.tv_nsec >= BILLION) {
                        m_t.tv_nsec -= BILLION;
                        m_t.tv_sec++;
                }
        }
 
        template <typename T>
        constexpr14 void init_int(T dt) noexcept
        {
                // seconds only.
                m_negative = dt < 0;
                m_t.tv_sec = (time_t)(dt >= 0 ? dt : -dt);
                m_t.tv_nsec = 0;
        }
 
public:
        constexpr bool isNormal() const noexcept
        {
                return m_t.tv_sec >= 0 && m_t.tv_nsec >= 0 && m_t.tv_nsec < BILLION;
        }
 
        constexpr bool isNegative() const noexcept
        {
                return m_negative;
        }
 
        constexpr bool isPositive() const noexcept
        {
                return !isNegative();
        }
 
        constexpr bool isNull() const noexcept
        {
                return m_t.tv_sec == 0 && m_t.tv_nsec == 0;
        }
 
        constexpr bool isInfinite() const noexcept
        {
                return m_t.tv_sec > std::numeric_limits<time_t>::max() / 2;
        }
 
        constexpr bool hasPassed() const noexcept
        {
                return isNegative() || isNull();
        }
 
        constexpr struct timespec const& ts() const noexcept
        {
                return m_t;
        }
 
        constexpr14 double s() const noexcept
        {
                return s<double>();
        }
 
        template <typename T>
        constexpr14 T s() const noexcept
        {
                T t = (T)m_t.tv_sec + (T)m_t.tv_nsec * (T)1e-9;
                if(m_negative)
                        t = -t;
                return t;
        }
 
        constexpr bool isAbsBiggerThan(TimeInterval const& t) const noexcept
        {
                return m_t.tv_sec > t.m_t.tv_sec
                       || (m_t.tv_sec == t.m_t.tv_sec && m_t.tv_nsec > t.m_t.tv_nsec);
        }
 
        constexpr bool isBiggerThan(TimeInterval const& t) const noexcept
        {
                return (!m_negative && t.m_negative)
                       || (!m_negative && !t.m_negative && this->isAbsBiggerThan(t))
                       || (m_negative && t.m_negative && t.isAbsBiggerThan(*this));
        }
 
        constexpr bool operator==(TimeInterval const& rhs) const noexcept
        {
                return m_t.tv_nsec == rhs.m_t.tv_nsec && m_t.tv_sec == rhs.m_t.tv_sec
                       && m_negative == rhs.m_negative;
        }
 
        constexpr bool operator>(TimeInterval const& rhs) const noexcept
        {
                return this->isBiggerThan(rhs);
        }
 
        constexpr bool operator>=(TimeInterval const& rhs) const noexcept
        {
                return *this == rhs || this->isBiggerThan(rhs);
        }
 
        constexpr bool operator<(TimeInterval const& rhs) const noexcept
        {
                return !(*this >= rhs);
        }
 
        constexpr bool operator<=(TimeInterval const& rhs) const noexcept
        {
                return *this == rhs || !(*this > rhs);
        }
 
        constexpr14 void add(TimeInterval const& t) noexcept
        {
                if(t.m_negative == m_negative) {
                        // Check for overflow.
                        if(isInfinite() || t.isInfinite()
                           || std::numeric_limits<time_t>::max() - m_t.tv_sec - 1 <= t.m_t.tv_sec) {
                                m_t.tv_sec = std::numeric_limits<time_t>::max(); // infinite
                        } else {
                                // Add in same sign direction.
                                m_t.tv_sec += t.m_t.tv_sec;
                                m_t.tv_nsec += t.m_t.tv_nsec;
                                if(m_t.tv_nsec > BILLION) {
                                        m_t.tv_nsec -= BILLION;
                                        m_t.tv_sec++;
                                }
                        }
                } else {
                        if(t.isAbsBiggerThan(*this)) {
                                // Add in other sign direction with sign flip.
                                m_t.tv_sec = t.m_t.tv_sec - m_t.tv_sec;
                                m_t.tv_nsec = t.m_t.tv_nsec - m_t.tv_nsec;
                                m_negative = !m_negative;
                        } else {
                                // Add in other sign direction (but without sign flip).
                                m_t.tv_sec -= t.m_t.tv_sec;
                                m_t.tv_nsec -= t.m_t.tv_nsec;
                        }
                        if(m_t.tv_nsec < 0) {
                                m_t.tv_nsec += BILLION;
                                m_t.tv_sec--;
                        }
                }
        }
 
        constexpr14 void sub(TimeInterval const& t) noexcept
        {
                add(TimeInterval(t.ts().tv_sec, t.ts().tv_nsec, !t.isNegative()));
        }
 
        template <typename T>
        constexpr14 void mul(T x) noexcept
        {
                *this = TimeInterval(s<T>() * x);
        }
 
        constexpr14 TimeInterval& operator+=(TimeInterval const& rhs) noexcept
        {
                add(rhs);
                return *this;
        }
 
        constexpr14 TimeInterval operator+(TimeInterval const& rhs) const noexcept
        {
                TimeInterval ti(*this);
                ti += rhs;
                return ti;
        }
 
        constexpr14 TimeInterval& operator-=(TimeInterval const& rhs) noexcept
        {
                sub(rhs);
                return *this;
        }
 
        constexpr14 TimeInterval operator-(TimeInterval const& rhs) const noexcept
        {
                TimeInterval ti(*this);
                ti -= rhs;
                return ti;
        }
 
        constexpr14 TimeInterval operator-() const noexcept
        {
                return TimeInterval(ts().tv_sec, ts().tv_nsec, !isNegative());
        }
 
        template <typename T>
        constexpr14 TimeInterval& operator*=(T x) noexcept
        {
                mul<T>(x);
                return *this;
        }
 
        template <typename T>
        constexpr14 TimeInterval operator*(T x) const noexcept
        {
                return TimeInterval(s<T>() * x);
        }
 
        template <typename T>
        constexpr14 TimeInterval& operator/=(T x) noexcept
        {
                mul<T>((T)1 / x);
                return *this;
        }
 
        template <typename T>
        constexpr14 TimeInterval operator/(T x) const noexcept
        {
                return TimeInterval(s<T>() / x);
        }
 
        string str() const
        {
                string res;
                if(isInfinite()) {
                        res = "infinity";
                        return res;
                }
 
                if(m_negative)
                        res = "-";
 
#       ifdef ZTH_OS_BAREMETAL
                // Do a simplified print without float formatting support.
                if(m_t.tv_sec >= 60)
                        res += format("%u s", (unsigned int)m_t.tv_sec);
                else if(m_t.tv_sec > 0)
                        res +=
                                format("%u.%03u s", (unsigned int)m_t.tv_sec,
                                       (unsigned int)(m_t.tv_nsec / 1000000L));
                else
                        res += format("%u us", (unsigned int)m_t.tv_nsec / 1000U);
#       else
                uint64_t d = (uint64_t)(m_t.tv_sec / 3600 / 24);
                time_t rest = m_t.tv_sec - d * 3600 * 24;
                bool doPrint = d > 0;
                if(doPrint)
                        res += format("%" PRIu64 "d:", d);
 
                int h = int(rest / 3600);
                rest -= h * 3600;
                if(doPrint) {
                        res += format("%02d:", h);
                } else if(h > 0) {
                        res += format("%d:", h);
                        doPrint = true;
                }
 
                int m = int(rest / 60);
                rest -= m * 60;
                if(doPrint) {
                        res += format("%02d:", m);
                } else if(m > 0) {
                        res += format("%d:", m);
                        doPrint = true;
                }
 
                double sec = (double)rest + (double)m_t.tv_nsec * 1e-9;
                if(doPrint) {
                        res += format("%06.3f", sec);
                } else {
                        res += format("%g s", sec);
                }
#       endif
 
                return res;
        }
 
private:
        struct timespec m_t;
        bool m_negative;
};
 
template <>
inline cow_string str<TimeInterval const&>(TimeInterval const& value)
{
        return value.str();
}
 
#       if __cplusplus >= 201103L
ZTH_EXPORT constexpr14 inline TimeInterval operator"" _s(unsigned long long int x) noexcept
{
        return TimeInterval((time_t)std::min<unsigned long long int>(
                x, (unsigned long long int)std::numeric_limits<time_t>::max()));
}
 
ZTH_EXPORT constexpr14 inline TimeInterval operator"" _ms(unsigned long long int x) noexcept
{
        return TimeInterval::from_ms(x);
}
 
ZTH_EXPORT constexpr14 inline TimeInterval operator"" _us(unsigned long long int x) noexcept
{
        return TimeInterval::from_us(x);
}
 
ZTH_EXPORT inline TimeInterval operator"" _s(long double x)
{
        return TimeInterval(x);
}
#       endif // C++11
 
class Timestamp {
        ZTH_CLASS_NEW_DELETE(Timestamp)
public:
        // null
        constexpr Timestamp() noexcept
                : m_t()
        {}
 
        // cppcheck-suppress noExplicitConstructor
        constexpr Timestamp(struct timespec const& ts) noexcept
                : m_t(ts)
        {}
 
        constexpr14 explicit Timestamp(time_t sec, long nsec = 0) noexcept
                : m_t()
        {
                m_t.tv_sec = sec;
                m_t.tv_nsec = nsec;
        }
 
        // cppcheck-suppress noExplicitConstructor
        Timestamp(TimeInterval const& ti)
                : m_t()
        {
                *this = now() + ti;
        }
 
        static Timestamp now()
        {
                Timestamp t;
                int res __attribute__((unused)) = clock_gettime(CLOCK_MONOTONIC, &t.m_t);
                zth_assert(res == 0);
                zth_assert(!t.isNull());
                return t;
        }
 
        constexpr struct timespec const& ts() const noexcept
        {
                return m_t;
        }
        constexpr operator struct timespec const &() const noexcept
        {
                return ts();
        }
 
        constexpr bool isBefore(Timestamp const& t) const noexcept
        {
                return ts().tv_sec < t.ts().tv_sec
                       || (ts().tv_sec == t.ts().tv_sec && ts().tv_nsec < t.ts().tv_nsec);
        }
 
        constexpr bool isAfter(Timestamp const& t) const noexcept
        {
                return t.isBefore(*this);
        }
 
        bool hasPassed() const noexcept
        {
                return now().isBefore(*this);
        }
 
        constexpr bool operator==(Timestamp const& rhs) const noexcept
        {
                return ts().tv_nsec == rhs.ts().tv_nsec && ts().tv_sec == rhs.ts().tv_sec;
        }
 
        constexpr bool operator!=(Timestamp const& rhs) const noexcept
        {
                return !(*this == rhs);
        }
        constexpr bool operator<(Timestamp const& rhs) const noexcept
        {
                return this->isBefore(rhs);
        }
        constexpr bool operator<=(Timestamp const& rhs) const noexcept
        {
                return *this == rhs || this->isBefore(rhs);
        }
        constexpr bool operator>(Timestamp const& rhs) const noexcept
        {
                return rhs.isBefore(*this);
        }
        constexpr bool operator>=(Timestamp const& rhs) const noexcept
        {
                return *this == rhs || rhs.isBefore(*this);
        }
 
        constexpr14 TimeInterval timeTo(Timestamp const& t) const
        {
                return TimeInterval(t.ts().tv_sec, t.ts().tv_nsec)
                       - TimeInterval(ts().tv_sec, ts().tv_nsec);
        }
 
        TimeInterval passed() const
        {
                // Assume we are in the past. If so, interval calculations are
                // simpler than in the general timeTo() case.
                Timestamp t = now();
                zth_assert(!isAfter(t));
 
                t.m_t.tv_sec -= m_t.tv_sec;
                t.m_t.tv_nsec -= m_t.tv_nsec;
                if(t.m_t.tv_nsec < 0) {
                        t.m_t.tv_sec--;
                        t.m_t.tv_nsec += TimeInterval::BILLION;
                }
 
                return TimeInterval(t.m_t.tv_sec, t.m_t.tv_nsec);
        }
 
        constexpr14 void add(TimeInterval const& dt) noexcept
        {
                TimeInterval t(m_t.tv_sec, m_t.tv_nsec);
                t += dt;
                zth_assert(t.isPositive());
                m_t = t.ts();
        }
 
        constexpr14 Timestamp& operator+=(TimeInterval const& dt) noexcept
        {
                add(dt);
                return *this;
        }
 
        constexpr14 Timestamp operator+(TimeInterval const& dt) const noexcept
        {
                Timestamp t(*this);
                return t += dt;
        }
 
        constexpr14 Timestamp& operator-=(TimeInterval const& dt) noexcept
        {
                add(-dt);
                return *this;
        }
 
        constexpr14 Timestamp operator-(TimeInterval const& dt) const noexcept
        {
                Timestamp t(*this);
                return t -= dt;
        }
 
        constexpr14 TimeInterval operator-(Timestamp const& rhs) const noexcept
        {
                return rhs.timeTo(*this);
        }
 
        static constexpr Timestamp null() noexcept
        {
                return Timestamp();
        }
 
        constexpr bool isNull() const noexcept
        {
                return m_t.tv_sec == 0 && m_t.tv_nsec == 0;
        }
 
private:
        struct timespec m_t;
};
 
#       ifdef ZTH_OS_MAC
// Should be const, but the alias-trick does not work on OSX.
extern Timestamp /* const */ startTime;
#       else
extern Timestamp const startTime;
#       endif
 
} // namespace zth
 
#endif // __cplusplus
#endif // ZTH_TIME_H