fsfw/contrib/fsfw_contrib/etl-20.39.4/include/etl/log.h

///\file

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

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

Copyright(c) 2014 John Wellbelove

Permission is hereby granted, free of charge, to any person obtaining a copy
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******************************************************************************/

#ifndef ETL_LOG_INCLUDED
#define ETL_LOG_INCLUDED

#include "platform.h"

#include <stddef.h>

///\defgroup log log
/// log<N, BASE> : Calculates logs to any base, rounded down to the nearest integer.<br>
/// log2<N>      : Calculates logs to base 2, rounded down to the nearest integer.<br>
/// log10<N>     : Calculates logs to base 10, rounded down to the nearest integer.<br>
///\ingroup maths

namespace etl
{
  //***************************************************************************
  ///\ingroup log
  /// The base generic log template.
  /// Defines <b>value</b> as the log of the number at the specified base.
  /// The result is rounded down to the next integer.
  ///\tparam NV   The number to find the log of.
  ///\tparam BASE The base of the log.
  //***************************************************************************
  template <size_t NV, size_t BASE>
  struct log
  {
    enum value_type
    {
      // Recursive definition.
      value = (NV >= BASE) ? 1 + log<NV / BASE, BASE>::value : 0
    };
  };

  //***************************************************************************
  // Specialisation for N = 1
  //***************************************************************************
  template <size_t BASE>
  struct log<1, BASE>
  {
    enum value_type
    {
      value = 0
    };
  };

  //***************************************************************************
  // Specialisation for N = 0
  //***************************************************************************
  template <size_t BASE>
  struct log<0, BASE>
  {
    enum value_type
    {
      value = 0
    };
  };

#if ETL_USING_CPP17
  template <size_t NV, size_t BASE>
  inline constexpr size_t log_v = log<NV, BASE>::value;
#endif

  //***************************************************************************
  ///\ingroup log
  /// Calculates base 2 logs.
  //***************************************************************************
  template <size_t NV>
  struct log2
  {
    enum value_type
    {
      value = log<NV, 2>::value
    };
  };

#if ETL_USING_CPP17
  template <size_t NV>
  inline constexpr size_t log2_v = log2<NV>::value;
#endif

  //***************************************************************************
  ///\ingroup log
  /// Calculates base 10 logs.
  //***************************************************************************
  template <size_t NV>
  struct log10
  {
    enum value_type
    {
      value = log<NV, 10>::value
    };
  };

#if ETL_USING_CPP17
  template <size_t NV>
  inline constexpr size_t log10_v = log10<NV>::value;
#endif
}

#endif