back_emplace.hpp

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# /*
#   Created by YongGyu Lee on 2020/12/08.
# */
#
# ifndef VCCC_TYPE_SUPPORT_BACK_EMPLACE_HPP
# define VCCC_TYPE_SUPPORT_BACK_EMPLACE_HPP
#
# include <iterator>
#
# ifdef _MSC_VER
# pragma warning( push )
# pragma warning( disable : 4996)
# endif
 
namespace vccc {
 
namespace internal {
 
# if __cplusplus >= 201703L
struct back_emplace_iterator_base {
  using iterator_category = std::output_iterator_tag;
 
  using value_type      = void;
# if __cplusplus >= 202002L
  using difference_type = std::ptrdiff_t;
# else
  using difference_type = void;
# endif
  using pointer         = void;
  using reference       = void;
};
# else
using back_emplace_iterator_base =
    std::iterator<std::output_iterator_tag,
                  void,
                  void,
                  void,
                  void>;
# endif
 
} // namespace internal
 
 
template <class Container>
class back_emplace_iterator
    : public internal::back_emplace_iterator_base
{
 protected:
  Container* container;
 public:
  using container_type = Container;
 
  explicit back_emplace_iterator(Container& x) : container(std::addressof(x)) {}
  back_emplace_iterator& operator=(const typename Container::value_type& value)
  {container->emplace_back(value); return *this;}
  back_emplace_iterator& operator=(typename Container::value_type&& value)
  {container->emplace_back(std::move(value)); return *this;}
  back_emplace_iterator& operator*()     {return *this;}
  back_emplace_iterator& operator++()    {return *this;}
  back_emplace_iterator  operator++(int) {return *this;}
};
 
template<typename Container>
back_emplace_iterator<Container>
back_emplacer(Container& container)
{
  return back_emplace_iterator<Container>(container);
}
 
 
} // namespace vccc
 
# ifdef _MSC_VER
# pragma warning( pop )
# endif
 
# endif // VCCC_TYPE_SUPPORT_BACK_EMPLACE_HPP