clocks.h

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/******************************************************************************
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Embedded Template Library.
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Copyright(c) 2025 John Wellbelove
 
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#ifndef ETL_IN_CHRONO_H
  #error DO NOT DIRECTLY INCLUDE THIS FILE. USE CHRONO.H
#endif
 
#if !defined(ETL_CHRONO_SYSTEM_CLOCK_DURATION)
  #define ETL_CHRONO_SYSTEM_CLOCK_DURATION etl::chrono::nanoseconds
#endif
 
#if !defined(ETL_CHRONO_SYSTEM_CLOCK_IS_STEADY)
  #define ETL_CHRONO_SYSTEM_CLOCK_IS_STEADY true
#endif
 
#if !defined(ETL_CHRONO_HIGH_RESOLUTION_CLOCK_DURATION)
  #define ETL_CHRONO_HIGH_RESOLUTION_CLOCK_DURATION etl::chrono::nanoseconds
#endif
 
#if !defined(ETL_CHRONO_HIGH_RESOLUTION_CLOCK_IS_STEADY)
  #define ETL_CHRONO_HIGH_RESOLUTION_CLOCK_IS_STEADY true
#endif
 
#if !defined(ETL_CHRONO_STEADY_CLOCK_DURATION)
#define ETL_CHRONO_STEADY_CLOCK_DURATION etl::chrono::nanoseconds
#endif
 
extern "C" ETL_CHRONO_SYSTEM_CLOCK_DURATION::rep          etl_get_system_clock();
extern "C" ETL_CHRONO_HIGH_RESOLUTION_CLOCK_DURATION::rep etl_get_high_resolution_clock();
extern "C" ETL_CHRONO_STEADY_CLOCK_DURATION::rep          etl_get_steady_clock();
 
namespace etl
{
  namespace chrono
  {
    namespace private_chrono
    {
      template <bool b>
      struct is_steady_trait
      {
        static ETL_CONSTANT bool is_steady = b;
      };
 
      template <bool b>
      ETL_CONSTANT bool is_steady_trait<b>::is_steady;
    }
 
    //*************************************************************************
    //*************************************************************************
    class system_clock : public private_chrono::is_steady_trait<ETL_CHRONO_SYSTEM_CLOCK_IS_STEADY>
    {
    public:
 
      using duration   = ETL_CHRONO_SYSTEM_CLOCK_DURATION;
      using rep        = duration::rep;
      using period     = duration::period;
      using time_point = etl::chrono::time_point<system_clock, duration>;
 
      //*************************************************************************
      static time_point now() ETL_NOEXCEPT
      {
        return time_point(duration(etl_get_system_clock()));
      }
 
      //*************************************************************************
      static etl::time_t to_time_t(const time_point& t) ETL_NOEXCEPT
      {
        // Get the duration since the epoch
        duration dur = t.time_since_epoch();
 
        // Convert the duration to seconds
        return dur.count() / duration::period::den;
      }
 
      //*************************************************************************
      static time_point from_time_t(etl::time_t t) ETL_NOEXCEPT
      {
        // Convert seconds to the appropriate duration
        duration dur(t * duration::period::den);
 
        // Construct and return the time_point
        return time_point(dur);
      }
    };
 
    //*************************************************************************
    //*************************************************************************
    class high_resolution_clock : public private_chrono::is_steady_trait<ETL_CHRONO_HIGH_RESOLUTION_CLOCK_IS_STEADY>
    {
    public:
 
      using duration   = ETL_CHRONO_HIGH_RESOLUTION_CLOCK_DURATION;
      using rep        = duration::rep;
      using period     = duration::period;
      using time_point = etl::chrono::time_point<high_resolution_clock, duration>;
 
      //*************************************************************************
      static time_point now() ETL_NOEXCEPT
      {
        return time_point(duration(etl_get_high_resolution_clock()));
      }
    };
 
    //*************************************************************************
    //*************************************************************************
    class steady_clock : public private_chrono::is_steady_trait<true>
    {
    public:
 
      using duration   = ETL_CHRONO_STEADY_CLOCK_DURATION;
      using rep        = duration::rep;
      using period     = duration::period;
      using time_point = etl::chrono::time_point<steady_clock, duration>;
 
      //*************************************************************************
      static time_point now() ETL_NOEXCEPT
      {
        return time_point(duration(etl_get_steady_clock()));
      }
    };
 
    //***************************************************************************
    //***************************************************************************
    template <typename Duration>
    using sys_time = etl::chrono::time_point<etl::chrono::system_clock, Duration> ;
 
    using sys_seconds = sys_time<etl::chrono::seconds>;
    using sys_days    = sys_time<etl::chrono::days>;
 
    //***************************************************************************
    //***************************************************************************
    struct local_t 
    {
    };
 
    template <typename TDuration>
    using local_time = etl::chrono::time_point<etl::chrono::local_t, TDuration>;
 
    using local_seconds = local_time<etl::chrono::seconds>;
    using local_days    = local_time<etl::chrono::days>;
 
    //*************************************************************************
    //*************************************************************************
    template <typename TToClock, typename TFromClock, typename TFromDuration>
    ETL_CONSTEXPR14 etl::chrono::time_point<TToClock, typename TToClock::duration>
      clock_cast(const etl::chrono::time_point<TFromClock, TFromDuration>& from_time_point) ETL_NOEXCEPT
    {
      // Get the duration since the epoch of the FromClock
      auto from_duration = from_time_point.time_since_epoch();
 
      // Convert the duration to the ToClock's duration type
      auto to_duration = etl::chrono::duration_cast<typename TToClock::duration>(from_duration);
 
      // Construct and return the time_point for the ToClock
      return etl::chrono::time_point<TToClock, typename TToClock::duration>(to_duration);
    }
  }
}