// In header: <boost/date_time/adjust_functors.hpp>

template<typename date_type> 
class day_functor {
public:
  // types
  typedef date_type::duration_type duration_type;

  // construct/copy/destruct
  day_functor(int);

  // public member functions
  duration_type get_offset(const date_type &) const;
  duration_type get_neg_offset(const date_type &) const;
};