year_month_day.h

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/******************************************************************************
The MIT License(MIT)
 
Embedded Template Library.
https://github.com/ETLCPP/etl
https://www.etlcpp.com
 
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
 
namespace etl
{
  namespace chrono
  {
    class year_month_day_last;
 
    //*************************************************************************
    //*************************************************************************
    class year_month_day
    {
    public:
 
      //*************************************************************************
      //*************************************************************************
      ETL_CONSTEXPR year_month_day()
        : y()
        , m()
        , d()
      {
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_CONSTEXPR14 year_month_day(const etl::chrono::year&  y_, 
                                     const etl::chrono::month& m_, 
                                     const etl::chrono::day&   d_) ETL_NOEXCEPT
        : y(y_)
        , m(m_)
        , d(d_)
      {
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_CONSTEXPR14 year_month_day(const etl::chrono::year_month_day_last& ymdl) ETL_NOEXCEPT;
 
      //*************************************************************************
      //*************************************************************************
      ETL_CONSTEXPR14 year_month_day(const etl::chrono::sys_days& sd) ETL_NOEXCEPT
      {
        // Days since 1970-01-01
        int days_since_epoch = static_cast<int>(sd.time_since_epoch().count());
 
        // Start from 1970-01-01
        etl::chrono::year  current_year(1970);
        etl::chrono::month current_month(1);
 
        // Find the year
        while (true)
        {
          int days_in_year = current_year.is_leap() ? 366 : 365;
          
          if (days_since_epoch < days_in_year)
          {
            break;
          }
 
          days_since_epoch -= days_in_year;
          ++current_year;
        }
 
        // Find the month
        while (true)
        {
          unsigned char days_in_month = etl::chrono::private_chrono::days_in_month[current_month];
          if (current_month == etl::chrono::February && current_year.is_leap())
          {
            ++days_in_month;
          }
 
          if (days_since_epoch < days_in_month)
          {
            break;
          }
 
          days_since_epoch -= days_in_month;
          ++current_month;
        }
 
        // The remaining days are the day of the month (0-based)
        y = current_year;
        m = current_month;
        d = etl::chrono::day(static_cast<unsigned>(days_since_epoch) + 1);
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_CONSTEXPR14 year_month_day(const etl::chrono::local_days& ld) ETL_NOEXCEPT
      {
        etl::chrono::year_month_day ymd = sys_days(ld.time_since_epoch());
 
        y = ymd.year();
        m = ymd.month();
        d = ymd.day();
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_NODISCARD
      ETL_CONSTEXPR14 etl::chrono::year year() const ETL_NOEXCEPT
      {
        return y;
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_NODISCARD
      ETL_CONSTEXPR14 etl::chrono::month month() const ETL_NOEXCEPT
      {
        return m;
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_NODISCARD
      ETL_CONSTEXPR14 etl::chrono::day day() const ETL_NOEXCEPT
      {
        return d;
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_NODISCARD
      ETL_CONSTEXPR14 bool ok() const ETL_NOEXCEPT
      {       
        // Check if the year, month, and day are valid individually
        return y.ok() && 
               m.ok() && 
               d.ok() &&
               d <= max_day_for_month();
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_CONSTEXPR14 etl::chrono::year_month_day& operator +=(const etl::chrono::years& dy) ETL_NOEXCEPT
      {
        y += dy;
 
        return *this;
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_CONSTEXPR14 etl::chrono::year_month_day& operator +=(const etl::chrono::months& dm) ETL_NOEXCEPT
      {
        m += dm;
 
        return *this;
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_CONSTEXPR14 etl::chrono::year_month_day& operator -=(const etl::chrono::years& dy) ETL_NOEXCEPT
      {
        y -= dy;
 
        return *this;
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_CONSTEXPR14 etl::chrono::year_month_day& operator -=(const etl::chrono::months& dm) ETL_NOEXCEPT
      {
        m -= dm;
 
        return *this;
      }
 
      //***********************************************************************
      //***********************************************************************
      ETL_NODISCARD
      ETL_CONSTEXPR14 int compare(const year_month_day& other) const ETL_NOEXCEPT 
      {
        if (y < other.y) return -1;
        if (y > other.y) return 1;
        if (m < other.m) return -1;
        if (m > other.m) return 1;
        if (d < other.d) return -1;
        if (d > other.d) return 1;
      
        return 0;
      }
 
      //***********************************************************************
      //***********************************************************************
      ETL_NODISCARD
      ETL_CONSTEXPR14 operator etl::chrono::sys_days() const ETL_NOEXCEPT
      {
        int day_count = 0;
 
        // Add days for years since 1970
        for (etl::chrono::year yr(1970); yr < this->year(); ++yr)
        {
          day_count += yr.is_leap() ? 366 : 365;
        }
 
        // Add days for months in the current year
        for (etl::chrono::month mth(1); mth < this->month(); ++mth)
        {
          day_count += private_chrono::days_in_month[mth];
 
          if (mth == etl::chrono::February && this->year().is_leap())
          {
            ++day_count; // Add one day for leap year February
          }
        }
 
        // Add days for the current month
        day_count += static_cast<unsigned>(this->day()) - 1;
 
        return sys_days(etl::chrono::days(day_count));
      }
 
      //***********************************************************************
      //***********************************************************************
      ETL_NODISCARD
      ETL_CONSTEXPR14 explicit operator etl::chrono::local_days() const ETL_NOEXCEPT
      {
        return local_days(sys_days(*this).time_since_epoch());
      }
 
    private:
 
      //***********************************************************************
      //***********************************************************************
      ETL_CONSTEXPR14 etl::chrono::day max_day_for_month() const
      {
        unsigned char count = 0;
 
        if (y.ok() && m.ok())
        {
          count = private_chrono::days_in_month[m];
 
          if (y.is_leap() && (m == February))
          {
            ++count;
          }
        }
 
        return etl::chrono::day(count);
      }
 
      etl::chrono::year  y;
      etl::chrono::month m;
      etl::chrono::day   d;
    };
 
    //*************************************************************************
    //*************************************************************************
    inline ETL_CONSTEXPR14 etl::chrono::year_month_day operator +(const etl::chrono::year_month_day& ymd,
                                                                  const etl::chrono::years&          dy) ETL_NOEXCEPT
    {
      return etl::chrono::year_month_day(ymd.year() + dy, ymd.month(), ymd.day());
    }
 
    //*************************************************************************
    //*************************************************************************
    inline ETL_CONSTEXPR14 etl::chrono::year_month_day operator +(const etl::chrono::years&          dy,
                                                                  const etl::chrono::year_month_day& ymd) ETL_NOEXCEPT
    {
      return etl::chrono::year_month_day(ymd.year() + dy, ymd.month(), ymd.day());
    }
 
    //*************************************************************************
    //*************************************************************************
    inline ETL_CONSTEXPR14 etl::chrono::year_month_day operator +(const etl::chrono::year_month_day& ymd,
                                                                  const etl::chrono::months&         dm) ETL_NOEXCEPT
    {
      return etl::chrono::year_month_day(ymd.year(), ymd.month() + dm, ymd.day());
    }
 
    //*************************************************************************
    //*************************************************************************
    inline ETL_CONSTEXPR14 etl::chrono::year_month_day operator +(const etl::chrono::months&         dm,
                                                                  const etl::chrono::year_month_day& ymd) ETL_NOEXCEPT
    {
      return etl::chrono::year_month_day(ymd.year(), ymd.month() + dm, ymd.day());
    }
 
    //*************************************************************************
    //*************************************************************************
    inline ETL_CONSTEXPR14 etl::chrono::year_month_day operator -(const etl::chrono::year_month_day& ymd,
                                                                  const etl::chrono::years&      dy) ETL_NOEXCEPT
    {
      return etl::chrono::year_month_day(ymd.year() - dy, ymd.month(), ymd.day());
    }
 
    //*************************************************************************
    //*************************************************************************
    inline ETL_CONSTEXPR14 etl::chrono::year_month_day operator -(const etl::chrono::year_month_day& ymd,
                                                                  const etl::chrono::months&     dm) ETL_NOEXCEPT
    {
      return etl::chrono::year_month_day(ymd.year(), ymd.month() - dm, ymd.day());
    }
 
    //*************************************************************************
    //*************************************************************************
    inline ETL_CONSTEXPR14 bool operator ==(const etl::chrono::year_month_day& lhs, 
                                            const etl::chrono::year_month_day& rhs) ETL_NOEXCEPT
    {
      return (lhs.year()  == rhs.year())  &&
             (lhs.month() == rhs.month()) &&
             (lhs.day()   == rhs.day());
    }
 
    //*************************************************************************
    //*************************************************************************
    inline ETL_CONSTEXPR14 bool operator !=(const etl::chrono::year_month_day& lhs, 
                                            const etl::chrono::year_month_day& rhs) ETL_NOEXCEPT
    {
      return !(lhs == rhs);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_NODISCARD ETL_CONSTEXPR14
    inline bool operator <(const etl::chrono::year_month_day& lhs,
                           const etl::chrono::year_month_day& rhs) ETL_NOEXCEPT
    {
      if (lhs.year() < rhs.year())
      {
        return true;
      }
      else if (lhs.year() == rhs.year())
      {
        if (lhs.month() < rhs.month())
        {
          return true;
        }
        else if (lhs.month() == rhs.month())
        {
          return (lhs.day() < rhs.day());
        }
        else
        {
          return false;
        }
      }
      else
      {
        return false;
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_NODISCARD ETL_CONSTEXPR14
    inline bool operator <=(const etl::chrono::year_month_day& lhs,
                            const etl::chrono::year_month_day& rhs) ETL_NOEXCEPT
    {
      return !(rhs < lhs);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_NODISCARD ETL_CONSTEXPR14
    inline bool operator >(const etl::chrono::year_month_day& lhs,
                           const etl::chrono::year_month_day& rhs) ETL_NOEXCEPT
    {
      return rhs < lhs;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_NODISCARD ETL_CONSTEXPR14
    inline bool operator >=(const etl::chrono::year_month_day& lhs,
                            const etl::chrono::year_month_day& rhs) ETL_NOEXCEPT
    {
      return !(lhs < rhs);
    }
 
    //***********************************************************************
    //***********************************************************************
#if ETL_USING_CPP20
    [[nodiscard]] inline constexpr auto operator <=>(const etl::chrono::year_month_day& lhs, 
                                                     const etl::chrono::year_month_day& rhs) ETL_NOEXCEPT
    {
      auto cmp = lhs.year() <=> rhs.year();
 
      if (cmp != 0)
      {
        return cmp;
      }
 
      cmp = lhs.month() <=> rhs.month();
 
      if (cmp != 0)
      {
        return cmp;
      }
 
      return lhs.day() <=> rhs.day();
    }
#endif
 
    //*************************************************************************
    //*************************************************************************
    class year_month_day_last
    {
    public:
 
      //*************************************************************************
      //*************************************************************************
      ETL_CONSTEXPR14 year_month_day_last(const etl::chrono::year& y_,
                                          const etl::chrono::month_day_last& mdl_) ETL_NOEXCEPT
        : y(y_)
        , m(mdl_.month())
      {
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_NODISCARD
      ETL_CONSTEXPR14 etl::chrono::year year() const ETL_NOEXCEPT
      {
        return y;
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_NODISCARD
      ETL_CONSTEXPR14 etl::chrono::month month() const ETL_NOEXCEPT
      {
        return m;
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_NODISCARD
      ETL_CONSTEXPR14 etl::chrono::day day() const ETL_NOEXCEPT
      {
        etl::chrono::day d = etl::chrono::day(etl::chrono::private_chrono::days_in_month[m]);
 
        return (d == 28) && y.is_leap() ? etl::chrono::day(29) : d;
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_NODISCARD
      ETL_CONSTEXPR14 etl::chrono::month_day_last month_day_last() const ETL_NOEXCEPT
      {
        return etl::chrono::month_day_last(m);
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_NODISCARD
      ETL_CONSTEXPR14 bool ok() const ETL_NOEXCEPT
      {
        return y.ok() && m.ok();
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_CONSTEXPR14 etl::chrono::year_month_day_last& operator +=(const etl::chrono::years& dy) ETL_NOEXCEPT
      {
        y += dy;
 
        return *this;
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_CONSTEXPR14 etl::chrono::year_month_day_last& operator +=(const etl::chrono::months& dm) ETL_NOEXCEPT
      {
        m += dm;
 
        return *this;
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_CONSTEXPR14 etl::chrono::year_month_day_last& operator -=(const etl::chrono::years& dy) ETL_NOEXCEPT
      {
        y -= dy;
 
        return *this;
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_CONSTEXPR14 etl::chrono::year_month_day_last& operator -=(const etl::chrono::months& dm) ETL_NOEXCEPT
      {
        m -= dm;
 
        return *this;
      }
 
      //***********************************************************************
      //***********************************************************************
      ETL_NODISCARD
      ETL_CONSTEXPR14 int compare(const year_month_day_last& other) const ETL_NOEXCEPT 
      {
        if (y < other.y) return -1;
        if (y > other.y) return 1;
        if (m < other.m) return -1;
        if (m > other.m) return 1;
 
        return 0;
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_NODISCARD
      ETL_CONSTEXPR14 operator etl::chrono::sys_days() const ETL_NOEXCEPT
      {
        etl::chrono::year_month_day ymd(year(), month(), day());
 
        return etl::chrono::sys_days(ymd);
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_NODISCARD
      ETL_CONSTEXPR14 explicit operator etl::chrono::local_days() const ETL_NOEXCEPT
      {
        return local_days(sys_days(*this).time_since_epoch());
      }
 
    private:
 
      etl::chrono::year  y;
      etl::chrono::month m;
    };
 
    //*************************************************************************
    //*************************************************************************
    inline ETL_CONSTEXPR14 etl::chrono::year_month_day_last operator +(const etl::chrono::year_month_day_last& ymdl,
                                                                       const etl::chrono::years& dy) ETL_NOEXCEPT
    {
      return etl::chrono::year_month_day_last(ymdl.year() + dy, ymdl.month_day_last());
    }
 
    //*************************************************************************
    //*************************************************************************
    inline ETL_CONSTEXPR14 etl::chrono::year_month_day_last operator +(const etl::chrono::years& dy,
                                                                       const etl::chrono::year_month_day_last& ymdl) ETL_NOEXCEPT
    {
      return etl::chrono::year_month_day_last(ymdl.year() + dy, ymdl.month_day_last());
    }
 
    //*************************************************************************
    //*************************************************************************
    inline ETL_CONSTEXPR14 etl::chrono::year_month_day_last operator +(const etl::chrono::year_month_day_last& ymdl,
                                                                       const etl::chrono::months& dm) ETL_NOEXCEPT
    {
      return etl::chrono::year_month_day_last(ymdl.year(), etl::chrono::month_day_last(ymdl.month() + dm));
    }
 
    //*************************************************************************
    //*************************************************************************
    inline ETL_CONSTEXPR14 etl::chrono::year_month_day_last operator +(const etl::chrono::months& dm,
                                                                       const etl::chrono::year_month_day_last& ymdl) ETL_NOEXCEPT
    {
      return etl::chrono::year_month_day_last(ymdl.year(), etl::chrono::month_day_last(ymdl.month() + dm));
    }
 
    //*************************************************************************
    //*************************************************************************
    inline ETL_CONSTEXPR14 etl::chrono::year_month_day_last operator -(const etl::chrono::year_month_day_last& ymdl,
                                                                       const etl::chrono::years& dy) ETL_NOEXCEPT
    {
      return etl::chrono::year_month_day_last(ymdl.year() - dy, ymdl.month_day_last());
    }
 
    //*************************************************************************
    //*************************************************************************
    inline ETL_CONSTEXPR14 etl::chrono::year_month_day_last operator -(const etl::chrono::year_month_day_last& ymdl,
                                                                       const etl::chrono::months& dm) ETL_NOEXCEPT
    {
      return etl::chrono::year_month_day_last(ymdl.year(), etl::chrono::month_day_last(ymdl.month() - dm));
    }
 
    //*************************************************************************
    //*************************************************************************
    inline ETL_CONSTEXPR14 etl::chrono::year_month_day::year_month_day(const etl::chrono::year_month_day_last& ymdl) ETL_NOEXCEPT
      : y(ymdl.year())
      , m(ymdl.month())
      , d(ymdl.day())
    {
    }
 
    //*************************************************************************
    //*************************************************************************
    inline ETL_CONSTEXPR14 bool operator ==(const etl::chrono::year_month_day_last& lhs, 
                                            const etl::chrono::year_month_day_last& rhs) ETL_NOEXCEPT
    {
      return (lhs.year() == rhs.year()) &&
        (lhs.month() == rhs.month());
    }
 
    //*************************************************************************
    //*************************************************************************
    inline ETL_CONSTEXPR14 bool operator !=(const etl::chrono::year_month_day_last& lhs, 
                                            const etl::chrono::year_month_day_last& rhs) ETL_NOEXCEPT
    {
      return !(lhs == rhs);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_NODISCARD ETL_CONSTEXPR14
    inline bool operator <(const etl::chrono::year_month_day_last& lhs,
                           const etl::chrono::year_month_day_last& rhs) ETL_NOEXCEPT
    {
      if (lhs.year() < rhs.year())
      {
        return true;
      }
      else if (lhs.year() == rhs.year())
      {
        return (lhs.month() < rhs.month());
      }
      else
      {
        return false;
      }
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_NODISCARD ETL_CONSTEXPR14
    inline bool operator <=(const etl::chrono::year_month_day_last& lhs,
                            const etl::chrono::year_month_day_last& rhs) ETL_NOEXCEPT
    {
      return !(rhs < lhs);
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_NODISCARD ETL_CONSTEXPR14
    inline bool operator >(const etl::chrono::year_month_day_last& lhs,
                           const etl::chrono::year_month_day_last& rhs) ETL_NOEXCEPT
    {
      return rhs < lhs;
    }
 
    //*************************************************************************
    //*************************************************************************
    ETL_NODISCARD ETL_CONSTEXPR14
    inline bool operator >=(const etl::chrono::year_month_day_last& lhs,
                            const etl::chrono::year_month_day_last& rhs) ETL_NOEXCEPT
    {
      return !(lhs < rhs);
    }
 
    //***********************************************************************
    //***********************************************************************
#if ETL_USING_CPP20
    [[nodiscard]] inline constexpr auto operator <=>(const etl::chrono::year_month_day_last& lhs, 
                                                     const etl::chrono::year_month_day_last& rhs) ETL_NOEXCEPT
    {
      auto cmp1 = lhs.year() <=> rhs.year();
 
      if (cmp1 != 0)
      {
        return cmp1;
      }
      else
      {
        auto cmp2 = lhs.month() <=> rhs.month();
 
        if (cmp2 != 0)
        {
          return cmp2;
        }
        else
        {
          return lhs.month() <=> rhs.month();
        }
      }
    }
#endif
  }
 
  //*************************************************************************
  //*************************************************************************
#if ETL_USING_8BIT_TYPES
  template <>
  struct hash<etl::chrono::year_month_day>
  {
    size_t operator()(const etl::chrono::year_month_day& ymd) const
    {
      etl::chrono::year::rep  y = static_cast<etl::chrono::year::rep>(static_cast<unsigned>(ymd.year()));
      etl::chrono::month::rep m = static_cast<etl::chrono::month::rep>(static_cast<unsigned>(ymd.month()));
      etl::chrono::day::rep   d = static_cast<etl::chrono::day::rep>(static_cast<unsigned>(ymd.day()));
 
      uint8_t buffer[sizeof(y) + sizeof(m) + sizeof(d)];
 
      memcpy(buffer,                         &y, sizeof(y));
      memcpy(buffer + sizeof(y),             &m, sizeof(m));
      memcpy(buffer + sizeof(y) + sizeof(m), &d, sizeof(d));
 
      return etl::private_hash::generic_hash<size_t>(buffer, buffer + sizeof(y) + sizeof(m) + sizeof(d));
    }
  };
#endif
 
  //*************************************************************************
  //*************************************************************************
#if ETL_USING_8BIT_TYPES
  template <>
  struct hash<etl::chrono::year_month_day_last>
  {
    size_t operator()(const etl::chrono::year_month_day_last& ymdl) const
    {
      etl::chrono::year::rep  y = static_cast<etl::chrono::year::rep>(static_cast<unsigned>(ymdl.year()));
      etl::chrono::month::rep m = static_cast<etl::chrono::month::rep>(static_cast<unsigned>(ymdl.month()));
      etl::chrono::day::rep   d = static_cast<etl::chrono::day::rep>(static_cast<unsigned>(ymdl.day()));
 
      uint8_t buffer[sizeof(y) + sizeof(m) + sizeof(d)];
 
      memcpy(buffer,                         &y, sizeof(y));
      memcpy(buffer + sizeof(y),             &m, sizeof(m));
      memcpy(buffer + sizeof(y) + sizeof(m), &d, sizeof(d));
 
      return etl::private_hash::generic_hash<size_t>(buffer, buffer + sizeof(y) + sizeof(m) + sizeof(d));
    }
  };
#endif
}