Method iterator_impl

src/include/buffer.h:184–191

      const bool deep;   ///< if true, do not allow shallow ptr copies

      iterator_impl(typename std::conditional<is_const, const ptr*, ptr*>::type p,
		    size_t offset, bool d)
	: bp(p),
	  start(p->c_str() + offset),
	  pos(start),
	  end_ptr(p->end_c_str()),
	  deep(d)
      {}

      friend class ptr;