index_of_type.h

/******************************************************************************
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_INDEX_OF_TYPE_INCLUDED
#define ETL_INDEX_OF_TYPE_INCLUDED
 
#include "platform.h"
#include "static_assert.h"
#include "integral_limits.h"
 
namespace etl
{
#if ETL_USING_CPP11
 
  //***************************************************************************
  //***************************************************************************
  static ETL_CONSTANT size_t index_of_type_npos = etl::integral_limits<size_t>::max;
 
  //***************************************************************************
  //***************************************************************************
  template <typename T, typename... TTypes>
  struct index_of_type;
 
  //***************************************************************************
  //***************************************************************************
  template <typename T, typename T1, typename... TRest>
  struct index_of_type<T, T1, TRest...> : public etl::integral_constant<size_t, etl::is_same<T, T1>::value ? 0 :
                                                                                             (etl::index_of_type<T, TRest...>::value == etl::index_of_type_npos ? etl::index_of_type_npos : 
                                                                                              etl::index_of_type<T, TRest...>::value + 1)>
  {
  };
 
  //***************************************************************************
  //***************************************************************************
  template <typename T>
  struct index_of_type<T> : public etl::integral_constant<size_t, etl::index_of_type_npos>
  {
  };
 
#if ETL_USING_CPP17
  //***************************************************************************
  //***************************************************************************
  template <typename T, typename... TTypes>
  inline constexpr size_t index_of_type_v = etl::index_of_type<T, TTypes...>::value;
#endif
#endif
}
 
#endif