iterator.hpp 9.3 KB

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  1. //////////////////////////////////////////////////////////////////////////////
  2. //
  3. // (C) Copyright Ion Gaztanaga 2012-2012.
  4. // Distributed under the Boost Software License, Version 1.0.
  5. // (See accompanying file LICENSE_1_0.txt or copy at
  6. // http://www.boost.org/LICENSE_1_0.txt)
  7. //
  8. // See http://www.boost.org/libs/move for documentation.
  9. //
  10. //////////////////////////////////////////////////////////////////////////////
  11. //! \file
  12. #ifndef BOOST_MOVE_ITERATOR_HPP
  13. #define BOOST_MOVE_ITERATOR_HPP
  14. #include <boost/move/detail/config_begin.hpp>
  15. #include <boost/move/utility.hpp>
  16. #include <iterator> //std::iterator
  17. namespace boost {
  18. //////////////////////////////////////////////////////////////////////////////
  19. //
  20. // move_iterator
  21. //
  22. //////////////////////////////////////////////////////////////////////////////
  23. //! Class template move_iterator is an iterator adaptor with the same behavior
  24. //! as the underlying iterator except that its dereference operator implicitly
  25. //! converts the value returned by the underlying iterator's dereference operator
  26. //! to an rvalue reference. Some generic algorithms can be called with move
  27. //! iterators to replace copying with moving.
  28. template <class It>
  29. class move_iterator
  30. {
  31. public:
  32. typedef It iterator_type;
  33. typedef typename std::iterator_traits<iterator_type>::value_type value_type;
  34. #if !defined(BOOST_NO_CXX11_RVALUE_REFERENCES) || defined(BOOST_MOVE_DOXYGEN_INVOKED)
  35. typedef value_type && reference;
  36. #else
  37. typedef typename ::boost::move_detail::if_
  38. < ::boost::has_move_emulation_enabled<value_type>
  39. , ::boost::rv<value_type>&
  40. , value_type & >::type reference;
  41. #endif
  42. typedef It pointer;
  43. typedef typename std::iterator_traits<iterator_type>::difference_type difference_type;
  44. typedef typename std::iterator_traits<iterator_type>::iterator_category iterator_category;
  45. move_iterator()
  46. {}
  47. explicit move_iterator(It i)
  48. : m_it(i)
  49. {}
  50. template <class U>
  51. move_iterator(const move_iterator<U>& u)
  52. : m_it(u.base())
  53. {}
  54. iterator_type base() const
  55. { return m_it; }
  56. reference operator*() const
  57. {
  58. #if defined(BOOST_NO_CXX11_RVALUE_REFERENCES) || defined(BOOST_MOVE_OLD_RVALUE_REF_BINDING_RULES)
  59. return *m_it;
  60. #else
  61. return ::boost::move(*m_it);
  62. #endif
  63. }
  64. pointer operator->() const
  65. { return m_it; }
  66. move_iterator& operator++()
  67. { ++m_it; return *this; }
  68. move_iterator<iterator_type> operator++(int)
  69. { move_iterator<iterator_type> tmp(*this); ++(*this); return tmp; }
  70. move_iterator& operator--()
  71. { --m_it; return *this; }
  72. move_iterator<iterator_type> operator--(int)
  73. { move_iterator<iterator_type> tmp(*this); --(*this); return tmp; }
  74. move_iterator<iterator_type> operator+ (difference_type n) const
  75. { return move_iterator<iterator_type>(m_it + n); }
  76. move_iterator& operator+=(difference_type n)
  77. { m_it += n; return *this; }
  78. move_iterator<iterator_type> operator- (difference_type n) const
  79. { return move_iterator<iterator_type>(m_it - n); }
  80. move_iterator& operator-=(difference_type n)
  81. { m_it -= n; return *this; }
  82. reference operator[](difference_type n) const
  83. {
  84. #if defined(BOOST_NO_CXX11_RVALUE_REFERENCES) || defined(BOOST_MOVE_OLD_RVALUE_REF_BINDING_RULES)
  85. return m_it[n];
  86. #else
  87. return ::boost::move(m_it[n]);
  88. #endif
  89. }
  90. friend bool operator==(const move_iterator& x, const move_iterator& y)
  91. { return x.base() == y.base(); }
  92. friend bool operator!=(const move_iterator& x, const move_iterator& y)
  93. { return x.base() != y.base(); }
  94. friend bool operator< (const move_iterator& x, const move_iterator& y)
  95. { return x.base() < y.base(); }
  96. friend bool operator<=(const move_iterator& x, const move_iterator& y)
  97. { return x.base() <= y.base(); }
  98. friend bool operator> (const move_iterator& x, const move_iterator& y)
  99. { return x.base() > y.base(); }
  100. friend bool operator>=(const move_iterator& x, const move_iterator& y)
  101. { return x.base() >= y.base(); }
  102. friend difference_type operator-(const move_iterator& x, const move_iterator& y)
  103. { return x.base() - y.base(); }
  104. friend move_iterator operator+(difference_type n, const move_iterator& x)
  105. { return move_iterator(x.base() + n); }
  106. private:
  107. It m_it;
  108. };
  109. //is_move_iterator
  110. namespace move_detail {
  111. template <class I>
  112. struct is_move_iterator
  113. : public ::boost::move_detail::integral_constant<bool, false>
  114. {
  115. };
  116. template <class I>
  117. struct is_move_iterator< ::boost::move_iterator<I> >
  118. : public ::boost::move_detail::integral_constant<bool, true>
  119. {
  120. };
  121. } //namespace move_detail {
  122. //////////////////////////////////////////////////////////////////////////////
  123. //
  124. // move_iterator
  125. //
  126. //////////////////////////////////////////////////////////////////////////////
  127. //!
  128. //! <b>Returns</b>: move_iterator<It>(i).
  129. template<class It>
  130. inline move_iterator<It> make_move_iterator(const It &it)
  131. { return move_iterator<It>(it); }
  132. //////////////////////////////////////////////////////////////////////////////
  133. //
  134. // back_move_insert_iterator
  135. //
  136. //////////////////////////////////////////////////////////////////////////////
  137. //! A move insert iterator that move constructs elements at the
  138. //! back of a container
  139. template <typename C> // C models Container
  140. class back_move_insert_iterator
  141. : public std::iterator<std::output_iterator_tag, void, void, void, void>
  142. {
  143. C* container_m;
  144. public:
  145. typedef C container_type;
  146. typedef typename C::value_type value_type;
  147. typedef typename C::reference reference;
  148. explicit back_move_insert_iterator(C& x) : container_m(&x) { }
  149. back_move_insert_iterator& operator=(reference x)
  150. { container_m->push_back(boost::move(x)); return *this; }
  151. back_move_insert_iterator& operator=(BOOST_RV_REF(value_type) x)
  152. { reference rx = x; return this->operator=(rx); }
  153. back_move_insert_iterator& operator*() { return *this; }
  154. back_move_insert_iterator& operator++() { return *this; }
  155. back_move_insert_iterator& operator++(int) { return *this; }
  156. };
  157. //!
  158. //! <b>Returns</b>: back_move_insert_iterator<C>(x).
  159. template <typename C> // C models Container
  160. inline back_move_insert_iterator<C> back_move_inserter(C& x)
  161. {
  162. return back_move_insert_iterator<C>(x);
  163. }
  164. //////////////////////////////////////////////////////////////////////////////
  165. //
  166. // front_move_insert_iterator
  167. //
  168. //////////////////////////////////////////////////////////////////////////////
  169. //! A move insert iterator that move constructs elements int the
  170. //! front of a container
  171. template <typename C> // C models Container
  172. class front_move_insert_iterator
  173. : public std::iterator<std::output_iterator_tag, void, void, void, void>
  174. {
  175. C* container_m;
  176. public:
  177. typedef C container_type;
  178. typedef typename C::value_type value_type;
  179. typedef typename C::reference reference;
  180. explicit front_move_insert_iterator(C& x) : container_m(&x) { }
  181. front_move_insert_iterator& operator=(reference x)
  182. { container_m->push_front(boost::move(x)); return *this; }
  183. front_move_insert_iterator& operator=(BOOST_RV_REF(value_type) x)
  184. { reference rx = x; return this->operator=(rx); }
  185. front_move_insert_iterator& operator*() { return *this; }
  186. front_move_insert_iterator& operator++() { return *this; }
  187. front_move_insert_iterator& operator++(int) { return *this; }
  188. };
  189. //!
  190. //! <b>Returns</b>: front_move_insert_iterator<C>(x).
  191. template <typename C> // C models Container
  192. inline front_move_insert_iterator<C> front_move_inserter(C& x)
  193. {
  194. return front_move_insert_iterator<C>(x);
  195. }
  196. //////////////////////////////////////////////////////////////////////////////
  197. //
  198. // insert_move_iterator
  199. //
  200. //////////////////////////////////////////////////////////////////////////////
  201. template <typename C> // C models Container
  202. class move_insert_iterator
  203. : public std::iterator<std::output_iterator_tag, void, void, void, void>
  204. {
  205. C* container_m;
  206. typename C::iterator pos_;
  207. public:
  208. typedef C container_type;
  209. typedef typename C::value_type value_type;
  210. typedef typename C::reference reference;
  211. explicit move_insert_iterator(C& x, typename C::iterator pos)
  212. : container_m(&x), pos_(pos)
  213. {}
  214. move_insert_iterator& operator=(reference x)
  215. {
  216. pos_ = container_m->insert(pos_, ::boost::move(x));
  217. ++pos_;
  218. return *this;
  219. }
  220. move_insert_iterator& operator=(BOOST_RV_REF(value_type) x)
  221. { reference rx = x; return this->operator=(rx); }
  222. move_insert_iterator& operator*() { return *this; }
  223. move_insert_iterator& operator++() { return *this; }
  224. move_insert_iterator& operator++(int) { return *this; }
  225. };
  226. //!
  227. //! <b>Returns</b>: move_insert_iterator<C>(x, it).
  228. template <typename C> // C models Container
  229. inline move_insert_iterator<C> move_inserter(C& x, typename C::iterator it)
  230. {
  231. return move_insert_iterator<C>(x, it);
  232. }
  233. } //namespace boost {
  234. #include <boost/move/detail/config_end.hpp>
  235. #endif //#ifndef BOOST_MOVE_ITERATOR_HPP