text: /// \file
  // Range v3 library
  //
  //  Copyright Eric Niebler 2013-present
  //
  //  Use, modification and distribution is subject to the
  //  Boost Software License, Version 1.0. (See accompanying
  //  file LICENSE.txt or copy at
  //  http://www.boost.org/LICENSE_1_0.txt)
  //
  // Project home: https://github.com/ericniebler/range-v3
  //
  #ifndef RANGES_V3_ALGORITHM_COPY_BACKWARD_HPP
  #define RANGES_V3_ALGORITHM_COPY_BACKWARD_HPP
  
  #include <utility>
  #include "../range_fwd.hpp"
  #include "../begin_end.hpp"
  #include "../range_concepts.hpp"
  #include "../range_traits.hpp"
  #include "../utility/iterator_concepts.hpp"
  #include "../utility/iterator_traits.hpp"
  #include "../utility/static_const.hpp"
  #include "../utility/tagged_pair.hpp"
  #include "../algorithm/tagspec.hpp"
  
  namespace ranges
  {
      inline namespace v3
      {
          /// \addtogroup group-algorithms
          /// @{
          struct copy_backward_fn
          {
              template<typename I, typename S, typename O,
                  CONCEPT_REQUIRES_(
                      BidirectionalIterator<I>() && Sentinel<S, I>() &&
                      BidirectionalIterator<O>() &&
                      IndirectlyCopyable<I, O>()
                  )>
              tagged_pair<tag::in(I), tag::out(O)> operator()(I begin, S end_, O out) const
              {
                  I i = ranges::next(begin, end_), end = i;
                  while(begin != i)
                      *--out = *--i;
                  return {end, out};
              }
  
              template<typename Rng, typename O,
                  typename I = iterator_t<Rng>,
                  CONCEPT_REQUIRES_(
                      BidirectionalRange<Rng>() &&
                      BidirectionalIterator<O>() &&
                      IndirectlyCopyable<I, O>()
                  )>
              tagged_pair<tag::in(safe_iterator_t<Rng>), tag::out(O)>
              operator()(Rng &&rng, O out) const
              {
                  return (*this)(begin(rng), end(rng), std::move(out));
              }
          };
  
          /// \sa `copy_backward_fn`
          /// \ingroup group-algorithms
          RANGES_INLINE_VARIABLE(with_braced_init_args<copy_backward_fn>,
                                 copy_backward)
          /// @}
      } // namespace v3
  } // namespace ranges
  
  #endif // include guard
  