///\file

/******************************************************************************
The MIT License(MIT)

Embedded Template Library.
https://github.com/ETLCPP/etl
https://www.etlcpp.com

Copyright(c) 2014 jwellbelove

Permission is hereby granted, free of charge, to any person obtaining a copy
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in the Software without restriction, including without limitation the rights
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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******************************************************************************/

#ifndef ETL_FIBONACCI_INCLUDED
#define ETL_FIBONACCI_INCLUDED

#include <stddef.h>

#include "platform.h"

///\defgroup fibonacci fibonacci
/// fibonacci<N> : Calculates the Nth Fibonacci value.
///\ingroup maths

namespace etl
{
  //***************************************************************************
  ///\ingroup fibonacci
  /// Defines <b>value</b> as the Nth Fibbonacci number.
  ///\tparam N The number to find the Fibbonacci value of.
  //***************************************************************************
  template <size_t N>
  struct fibonacci
  {
    static ETL_CONSTANT size_t value = fibonacci<N - 1>::value + fibonacci<N - 2>::value;
  };

  //***************************************************************************
  // Specialisation for N = 1
  //***************************************************************************
  template <>
  struct fibonacci<1>
  {
    static ETL_CONSTANT size_t value = 1;
  };

  //***************************************************************************
  // Specialisation for N = 0
  //***************************************************************************
  template <>
  struct fibonacci<0>
  {
    static ETL_CONSTANT size_t value = 0;
  };

#if ETL_CPP17_SUPPORTED
  template <size_t N>
  inline constexpr size_t fibonacci_v = fibonacci<N>::value;
#endif
}

#endif
