power.h

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/******************************************************************************
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
of this software and associated documentation files(the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions :
 
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
 
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
******************************************************************************/
 
#ifndef ETL_POW_INCLUDED
#define ETL_POW_INCLUDED
 
#include "platform.h"
#include "log.h"
 
#include <stddef.h>
#include <stdint.h>

 
namespace etl
{
  namespace private_power
  {
#if ETL_NOT_USING_64BIT_TYPES
    typedef uint32_t type;
#else
    typedef uint64_t type;
#endif
  }
 
  //***************************************************************************
  //***************************************************************************
  template <size_t Value, size_t Power>
  struct power
  {
    static ETL_CONSTANT private_power::type value = Value * power<Value, Power - 1>::value;
  };
 
  template <size_t Value, size_t Power>
  ETL_CONSTANT private_power::type power<Value, Power>::value;
 
  //***************************************************************************
  //***************************************************************************
  template <size_t Value>
  struct power<Value, 0>
  {
    static ETL_CONSTANT private_power::type value = 1;
  };
 
  template <size_t Value>
  ETL_CONSTANT private_power::type power<Value, 0>::value;
 
#if ETL_USING_CPP17
  template <size_t Value, size_t Power>
  inline constexpr size_t power_v = power<Value, Power>::value;
#endif
 
  //***************************************************************************
  //***************************************************************************
  template <size_t Value>
  struct power_of_2_round_up
  {
    enum value_type
    {
      value = 1 << (etl::log2<Value - 1>::value + 1)
    };
  };
 
  //***************************************************************************
  //***************************************************************************
  template <>
  struct power_of_2_round_up<0>
  {
    enum value_type
    {
      value = 2
    };
  };
 
#if ETL_USING_CPP17
  template <size_t Value>
  inline constexpr size_t power_of_2_round_up_v = power_of_2_round_up<Value>::value;
#endif
 
  //***************************************************************************
  //***************************************************************************
  template <size_t Value>
  struct power_of_2_round_down
  {
    enum value_type
    {
      value = 1 << (etl::log2<Value - 1>::value)
    };
  };
 
  //***************************************************************************
  //***************************************************************************
  template <>
  struct power_of_2_round_down<0>
  {
    enum value_type
    {
      value = 2
    };
  };
 
  //***************************************************************************
  //***************************************************************************
  template <>
  struct power_of_2_round_down<1>
  {
    enum value_type
    {
      value = 2
    };
  };
 
  //***************************************************************************
  //***************************************************************************
  template <>
  struct power_of_2_round_down<2>
  {
    enum value_type
    {
      value = 2
    };
  };
 
#if ETL_USING_CPP17
  template <size_t Value>
  inline constexpr size_t power_of_2_round_down_v = power_of_2_round_down<Value>::value;
#endif
 
  //***************************************************************************
  //***************************************************************************
  template <size_t Value>
  struct is_power_of_2
  {
    static ETL_CONSTANT bool value = (Value & (Value - 1)) == 0;
  };
 
  //***************************************************************************
  //***************************************************************************
  template <>
  struct is_power_of_2<0>
  {
    static ETL_CONSTANT bool value = false;
  };
 
  //***************************************************************************
  //***************************************************************************
  template <>
  struct is_power_of_2<1>
  {
    static ETL_CONSTANT bool value = false;
  };
 
  template <size_t Value>
  ETL_CONSTANT bool is_power_of_2<Value>::value;
 
#if ETL_USING_CPP17
  template <size_t Value>
  inline constexpr size_t is_power_of_2_v = is_power_of_2<Value>::value;
#endif
}
 
#endif