weekday.h

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/******************************************************************************
The MIT License(MIT)
 
Embedded Template Library.
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Copyright(c) 2023 John Wellbelove
 
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#ifndef ETL_IN_CHRONO_H
  #error DO NOT DIRECTLY INCLUDE THIS FILE. USE CHRONO.H
#endif
 
#include <string.h>
 
namespace etl
{
  namespace chrono
  {
    class weekday;
    class weekday_indexed;
    class weekday_last;
    struct last_spec;
 
    ETL_CONSTEXPR14 etl::chrono::weekday operator +(const etl::chrono::weekday& m, const etl::chrono::days& ds)   ETL_NOEXCEPT;
    ETL_CONSTEXPR14 etl::chrono::weekday operator +(const etl::chrono::days& ds,   const etl::chrono::weekday& m) ETL_NOEXCEPT;
    ETL_CONSTEXPR14 etl::chrono::weekday operator -(const etl::chrono::weekday& m, const etl::chrono::days& ds)   ETL_NOEXCEPT;
 
    //***********************************************************************
    //***********************************************************************
    class weekday
    {
    public:
 
      //***********************************************************************
      //***********************************************************************
      ETL_CONSTEXPR weekday() ETL_NOEXCEPT
        : value(255U)
      {
      }
 
      //***********************************************************************
      //***********************************************************************
      ETL_CONSTEXPR explicit weekday(unsigned value_) ETL_NOEXCEPT
        : value(value_ == 7U ? 0U :value_)
      {
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_CONSTEXPR14 weekday(const etl::chrono::sys_days& sd) ETL_NOEXCEPT
        : value(255U)
      {
        // Get number of days since epoch.
        etl::chrono::days days_since_epoch = sd.time_since_epoch();
 
        // Convert to weekday. Beginning of the epoch was a Thursday (4).
        value = (days_since_epoch.count() + 4) % 7;
      }
 
      //*************************************************************************
      //*************************************************************************
      ETL_CONSTEXPR14 weekday(const etl::chrono::local_days& ld) ETL_NOEXCEPT
        : value(255U)
      {
        weekday wd(sys_days(ld.time_since_epoch()));
 
        value = wd.c_encoding();
      }
 
      //***********************************************************************
      //***********************************************************************
      ETL_CONSTEXPR14 weekday(const etl::chrono::weekday& other) ETL_NOEXCEPT
        : value(other.value)
      {
      }
 
      //***********************************************************************
      //***********************************************************************
      ETL_CONSTEXPR14 etl::chrono::weekday& operator =(const etl::chrono::weekday& rhs) ETL_NOEXCEPT
      {
        value = rhs.value;
 
        return *this;
      }
 
      //***********************************************************************
      //***********************************************************************
      ETL_CONSTEXPR14 etl::chrono::weekday& operator ++() ETL_NOEXCEPT
      {
        *this += etl::chrono::days(1);
 
        return *this;
      }
 
      //***********************************************************************
      //***********************************************************************
      ETL_CONSTEXPR14 etl::chrono::weekday operator ++(int) ETL_NOEXCEPT
      {
        const etl::chrono::weekday temp = *this;
        
        *this += etl::chrono::days(1);
 
        return temp;
      }
 
      //***********************************************************************
      //***********************************************************************
      ETL_CONSTEXPR14 etl::chrono::weekday& operator --() ETL_NOEXCEPT
      {
        *this -= etl::chrono::days(1);
 
        return *this;
      }
 
      //***********************************************************************
      //***********************************************************************
      ETL_CONSTEXPR14 etl::chrono::weekday operator --(int) ETL_NOEXCEPT
      {
        etl::chrono::weekday temp = *this;
 
        *this -= etl::chrono::days(1);
 
        return temp;
      }
 
      //***********************************************************************
      //***********************************************************************
      ETL_CONSTEXPR14 etl::chrono::weekday& operator +=(const etl::chrono::days& ds) ETL_NOEXCEPT
      {
        *this = *this + ds;
 
        return *this;
      }
 
      //***********************************************************************
      //***********************************************************************
      ETL_CONSTEXPR14 etl::chrono::weekday& operator -=(const etl::chrono::days& ds) ETL_NOEXCEPT
      {
        *this = *this - ds;
 
        return *this;
      }
 
      //***********************************************************************
      //***********************************************************************
      ETL_NODISCARD
      ETL_CONSTEXPR14 bool ok() const ETL_NOEXCEPT
      {
        return (c_encoding() <= 6U);
      }
 
      //***********************************************************************
      //***********************************************************************
      ETL_NODISCARD
      static ETL_CONSTEXPR14 unsigned min() ETL_NOEXCEPT
      {
        return 0;
      }
 
      //***********************************************************************
      //***********************************************************************
      ETL_NODISCARD
      static ETL_CONSTEXPR14 unsigned max() ETL_NOEXCEPT
      {
        return 6;
      }
 
      //***********************************************************************
      //***********************************************************************
      ETL_NODISCARD
      ETL_CONSTEXPR14 unsigned c_encoding() const ETL_NOEXCEPT
      {
        return value;
      }
 
      //***********************************************************************
      //***********************************************************************
      ETL_NODISCARD
      ETL_CONSTEXPR14 unsigned iso_encoding() const ETL_NOEXCEPT
      {
        return (value == 0U) ? 7U : value;
      }
 
      //***********************************************************************
      //***********************************************************************
      ETL_NODISCARD
      ETL_CONSTEXPR14 etl::chrono::weekday_indexed operator[](unsigned index) const ETL_NOEXCEPT;
        
      //***********************************************************************
      //***********************************************************************
      ETL_NODISCARD
      ETL_CONSTEXPR14 etl::chrono::weekday_last operator[](etl::chrono::last_spec last) const ETL_NOEXCEPT;
 
      //***********************************************************************
      //***********************************************************************
      ETL_NODISCARD
      ETL_CONSTEXPR14 bool is_weekend() const ETL_NOEXCEPT
      {
        return (c_encoding() == 0U) || (c_encoding() == 6U);
      }
 
    private:
 
      // The weekday value in C encoding.
      unsigned char value;
    };
 
    //***********************************************************************
    //***********************************************************************
    inline ETL_CONSTEXPR14 bool operator ==(const etl::chrono::weekday& wd1, const etl::chrono::weekday& wd2) ETL_NOEXCEPT
    {
      return (wd1.c_encoding() == wd2.c_encoding());
    }
 
    //***********************************************************************
    //***********************************************************************
    inline ETL_CONSTEXPR14 bool operator !=(const etl::chrono::weekday& wd1, const etl::chrono::weekday& wd2) ETL_NOEXCEPT
    {
      return !(wd1 == wd2);
    }
 
    //***********************************************************************
    //***********************************************************************
    inline ETL_CONSTEXPR14 etl::chrono::weekday operator +(const etl::chrono::weekday& wd, const etl::chrono::days& ds) ETL_NOEXCEPT
    {
      int delta = ds.count() % 7;
 
      unsigned int value = wd.c_encoding();
 
      // Adjust to allow a limited +-7 weekday delta
      value %= 7U;
      value += 7U;
      value += delta;
      value %= 7U;
 
      return etl::chrono::weekday(value);
    }
 
    //***********************************************************************
    //***********************************************************************
    inline ETL_CONSTEXPR14 etl::chrono::weekday operator +(const etl::chrono::days& ds, const etl::chrono::weekday& wd) ETL_NOEXCEPT
    {
      return wd + ds;
    }
 
    //***********************************************************************
    //***********************************************************************
    inline ETL_CONSTEXPR14 etl::chrono::weekday operator -(const etl::chrono::weekday& m, const etl::chrono::days& ds) ETL_NOEXCEPT
    {
      return m + etl::chrono::days(-ds.count());
    }
 
    //***********************************************************************
    //***********************************************************************
    inline ETL_CONSTEXPR14 etl::chrono::days operator -(const etl::chrono::weekday& wd1, const etl::chrono::weekday& wd2) ETL_NOEXCEPT
    {
      if (wd1.ok() && wd2.ok())
      {
        int diff = static_cast<int>(wd1.c_encoding()) - static_cast<int>(wd2.c_encoding());
        
        return etl::chrono::days((diff + 7) % 7);
      }
 
      return etl::chrono::days(0);
    }
 
#if ETL_USING_CPP17
    inline constexpr etl::chrono::weekday Sunday{ 0U };
    inline constexpr etl::chrono::weekday Monday{ 1U };
    inline constexpr etl::chrono::weekday Tuesday{ 2U };
    inline constexpr etl::chrono::weekday Wednesday{ 3U };
    inline constexpr etl::chrono::weekday Thursday{ 4U };
    inline constexpr etl::chrono::weekday Friday{ 5U };
    inline constexpr etl::chrono::weekday Saturday{ 6U };
#else
    static ETL_CONSTANT etl::chrono::weekday Sunday{ 0U };
    static ETL_CONSTANT etl::chrono::weekday Monday{ 1U };
    static ETL_CONSTANT etl::chrono::weekday Tuesday{ 2U };
    static ETL_CONSTANT etl::chrono::weekday Wednesday{ 3U };
    static ETL_CONSTANT etl::chrono::weekday Thursday{ 4U };
    static ETL_CONSTANT etl::chrono::weekday Friday{ 5U };
    static ETL_CONSTANT etl::chrono::weekday Saturday{ 6U };
#endif
 
    //***********************************************************************
    //***********************************************************************
    class weekday_indexed
    {
    public:
 
      //***********************************************************************
      //***********************************************************************
      ETL_CONSTEXPR weekday_indexed() ETL_NOEXCEPT
        : wd()
        , i()
      {
      }
 
      //***********************************************************************
      //***********************************************************************
      ETL_CONSTEXPR14 weekday_indexed(const etl::chrono::weekday& wd_, unsigned index_) ETL_NOEXCEPT
        : wd(wd_)
        , i(static_cast<uint_least8_t>(index_))
      {
      }
 
      //***********************************************************************
      //***********************************************************************
      ETL_CONSTEXPR14 weekday_indexed(const etl::chrono::weekday_indexed& other) ETL_NOEXCEPT
        : wd(other.wd)
        , i(other.i)
      {
      }
 
      //***********************************************************************
      //***********************************************************************
      ETL_CONSTEXPR14 etl::chrono::weekday_indexed& operator =(const etl::chrono::weekday_indexed& rhs) ETL_NOEXCEPT
      {
        wd = rhs.wd;
        i  = rhs.i;
 
        return *this;
      }
 
      //***********************************************************************
      //***********************************************************************
      ETL_NODISCARD
      ETL_NODISCARD ETL_CONSTEXPR14 etl::chrono::weekday weekday() const ETL_NOEXCEPT
      {
        return wd;
      }
 
      //***********************************************************************
      //***********************************************************************
      ETL_NODISCARD
      ETL_NODISCARD ETL_CONSTEXPR14 unsigned index() const ETL_NOEXCEPT
      {
        return i;
      }
 
      //***********************************************************************
      //***********************************************************************
      ETL_NODISCARD
      ETL_NODISCARD ETL_CONSTEXPR14 bool ok() const ETL_NOEXCEPT
      {
        return wd.ok() && (i >= 1U) && (i <= 5U);
      }
 
    private:
 
      etl::chrono::weekday wd;
      uint_least8_t i;
    };
 
    //***********************************************************************
    //***********************************************************************
    inline ETL_CONSTEXPR14 bool operator ==(const etl::chrono::weekday_indexed& wd1, const etl::chrono::weekday_indexed& wd2) ETL_NOEXCEPT
    {
      return (wd1.weekday() == wd2.weekday()) && 
             (wd1.index()   == wd2.index());
    }
 
    //***********************************************************************
    //***********************************************************************
    inline ETL_CONSTEXPR14 bool operator !=(const etl::chrono::weekday_indexed& wd1, const etl::chrono::weekday_indexed& wd2) ETL_NOEXCEPT
    {
      return !(wd1 == wd2);
    }
 
    //***********************************************************************
    //***********************************************************************
    class weekday_last
    {
    public:
 
      //***********************************************************************
      //***********************************************************************
      ETL_CONSTEXPR14 explicit weekday_last(const etl::chrono::weekday& wd_) ETL_NOEXCEPT
        : wd(wd_)
      {
      }
 
      //***********************************************************************
      //***********************************************************************
      ETL_CONSTEXPR14 weekday_last(const etl::chrono::weekday_last& other) ETL_NOEXCEPT
        : wd(other.wd)
      {
      }
 
      //***********************************************************************
      //***********************************************************************
      ETL_CONSTEXPR14 etl::chrono::weekday_last& operator =(const etl::chrono::weekday_last& rhs) ETL_NOEXCEPT
      {
        wd = rhs.wd;
 
        return *this;
      }
 
      //***********************************************************************
      //***********************************************************************
      ETL_NODISCARD ETL_CONSTEXPR14 etl::chrono::weekday weekday() const ETL_NOEXCEPT
      {
        return wd;
      }
 
      //***********************************************************************
      //***********************************************************************
      ETL_NODISCARD ETL_CONSTEXPR14 bool ok() const ETL_NOEXCEPT
      {
        return wd.ok();
      }
 
    private:
 
      etl::chrono::weekday wd;
    };
 
    //***********************************************************************
    //***********************************************************************
    inline ETL_CONSTEXPR14 bool operator ==(const etl::chrono::weekday_last& wd1, const etl::chrono::weekday_last& wd2) ETL_NOEXCEPT
    {
      return (wd1.weekday() == wd2.weekday());
    }
 
    //***********************************************************************
    //***********************************************************************
    inline ETL_CONSTEXPR14 etl::chrono::weekday_indexed etl::chrono::weekday::operator[](unsigned index) const ETL_NOEXCEPT
    {
      return etl::chrono::weekday_indexed(*this, index);
    }
 
    //***********************************************************************
    //***********************************************************************
    inline ETL_CONSTEXPR14 etl::chrono::weekday_last etl::chrono::weekday::operator[](etl::chrono::last_spec) const ETL_NOEXCEPT
    {
      return etl::chrono::weekday_last(*this);
    }
  }
 
  //*************************************************************************
  //*************************************************************************
#if ETL_USING_8BIT_TYPES
  template <>
  struct hash<etl::chrono::weekday>
  {
    size_t operator()(const etl::chrono::weekday& wd) const
    {
      unsigned value = wd.c_encoding();
      const uint8_t* p = reinterpret_cast<const uint8_t*>(&value);
 
      return etl::private_hash::generic_hash<size_t>(p, p + sizeof(unsigned));
    }
  };
#endif
 
  //*************************************************************************
  //*************************************************************************
#if ETL_USING_8BIT_TYPES
  template <>
  struct hash<etl::chrono::weekday_indexed>
  {
    size_t operator()(const etl::chrono::weekday_indexed& wdi) const
    {
      unsigned int a = wdi.weekday().c_encoding();
      unsigned int b = wdi.index();
 
      uint8_t buffer[sizeof(a) + sizeof(b)];
 
      memcpy(buffer,             &a, sizeof(a));
      memcpy(buffer + sizeof(a), &b, sizeof(b));
 
      return etl::private_hash::generic_hash<size_t>(buffer, buffer + sizeof(a) + sizeof(b));
    }
  };
#endif
 
  //*************************************************************************
  //*************************************************************************
#if ETL_USING_8BIT_TYPES
  template <>
  struct hash<etl::chrono::weekday_last>
  {
    size_t operator()(const etl::chrono::weekday_last& wdl) const
    {
      return etl::hash<etl::chrono::weekday>()(wdl.weekday());
    }
  };
#endif
}