class_traits.h

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/******************************************************************************
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Embedded Template Library.
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https://www.etlcpp.com
 
Copyright(c) 2021 jwellbelove
 
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#ifndef ETL_CLASS_TRAITS_INCLUDED
#define ETL_CLASS_TRAITS_INCLUDED
 
#include <stddef.h>
#include <stdint.h>
#include <utility>
 
#include "platform.h"
 
#if ETL_CPP11_SUPPORTED
 
namespace etl
{
  #if ETL_CPP11_SUPPORTED
  //***************************************************************************
  //***************************************************************************
  template <typename T>
  class has_begin
  {
    typedef char one;
    struct two
    {
      char x[2];
    };
 
    template <typename C>
    static constexpr one test(decltype(&C::begin)*);
    template <typename C>
    static constexpr two test(...);
 
  public:
 
    static constexpr bool value = (sizeof(test<T>(0)) == sizeof(char));
  };
 
    #if ETL_CPP17_SUPPORTED
  template <typename T>
  static constexpr bool has_begin_v = has_begin<T>::value;
    #endif
 
  //***************************************************************************
  //***************************************************************************
  template <typename T>
  class has_end
  {
    typedef char one;
    struct two
    {
      char x[2];
    };
 
    template <typename C>
    static constexpr one test(decltype(std::declval<C>().end()));
    template <typename C>
    static constexpr two test(...);
 
  public:
 
    static constexpr bool value = (sizeof(test<T>(0)) == sizeof(char));
  };
 
    #if ETL_CPP17_SUPPORTED
  template <typename T>
  static constexpr bool has_end_v = hasend<T>::value;
    #endif
 
  //***************************************************************************
  //***************************************************************************
  template <typename T>
  class has_size
  {
    typedef char one;
    struct two
    {
      char x[2];
    };
 
    template <typename C>
    static one test(decltype(std::declval<C>().size()));
    template <typename C>
    static two test(...);
 
  public:
 
    static constexpr bool value = (sizeof(test<T>(0)) == sizeof(char));
  };
 
    #if ETL_CPP17_SUPPORTED
  template <typename T>
  static constexpr bool has_size_v = has_size<T>::value;
    #endif
 
  //***************************************************************************
  //***************************************************************************
  template <typename T>
  class has_max_size
  {
    typedef char one;
    struct two
    {
      char x[2];
    };
 
    template <typename C>
    static one test(decltype(std::declval<C>().max_size()));
    template <typename C>
    static two test(...);
 
  public:
 
    static constexpr bool value = (sizeof(test<T>(0)) == sizeof(char));
  };
 
    #if ETL_CPP17_SUPPORTED
  template <typename T>
  static constexpr bool has_max_size_v = has_max_size<T>::value;
    #endif
 
  //***************************************************************************
  //***************************************************************************
  template <typename T>
  class has_empty
  {
    typedef char one;
    struct two
    {
      char x[2];
    };
 
    template <typename C>
    static constexpr one test(decltype(std::declval<C>().empty()));
    template <typename C>
    static constexpr two test(...);
 
  public:
 
    static constexpr bool value = (sizeof(test<T>(0)) == sizeof(char));
  };
 
    #if ETL_CPP17_SUPPORTED
  template <typename T>
  static constexpr bool has_empty_v = has_empty<T>::value;
    #endif
 
  //***************************************************************************
  //***************************************************************************
  template <typename T>
  class has_data
  {
    typedef char one;
    struct two
    {
      char x[2];
    };
 
    template <typename C>
    static constexpr one test(decltype(std::declval<C>().data()));
    template <typename C>
    static constexpr two test(...);
 
  public:
 
    static constexpr bool value = (sizeof(test<T>(0)) == sizeof(char));
  };
 
    #if ETL_CPP17_SUPPORTED
  template <typename T>
  static constexpr bool has_data_v = has_data<T>::value;
    #endif
  #endif
} // namespace etl
 
#endif
 
#endif // ETL_CLASS_TRAITS_INCLUDED