cons_iterator.hpp 3.5 KB

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  1. /*=============================================================================
  2. Copyright (c) 2001-2011 Joel de Guzman
  3. Copyright (c) 2005 Eric Niebler
  4. Distributed under the Boost Software License, Version 1.0. (See accompanying
  5. file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  6. ==============================================================================*/
  7. #if !defined(FUSION_CONS_ITERATOR_07172005_0849)
  8. #define FUSION_CONS_ITERATOR_07172005_0849
  9. #include <boost/fusion/support/config.hpp>
  10. #include <boost/type_traits/add_const.hpp>
  11. #include <boost/fusion/support/iterator_base.hpp>
  12. #include <boost/fusion/container/list/detail/deref_impl.hpp>
  13. #include <boost/fusion/container/list/detail/next_impl.hpp>
  14. #include <boost/fusion/container/list/detail/value_of_impl.hpp>
  15. #include <boost/fusion/container/list/detail/equal_to_impl.hpp>
  16. #include <boost/fusion/container/list/list_fwd.hpp>
  17. namespace boost { namespace fusion
  18. {
  19. struct nil_;
  20. struct cons_iterator_tag;
  21. struct forward_traversal_tag;
  22. template <typename Cons>
  23. struct cons_iterator_identity;
  24. template <typename Cons = nil_>
  25. struct cons_iterator : iterator_base<cons_iterator<Cons> >
  26. {
  27. typedef cons_iterator_tag fusion_tag;
  28. typedef forward_traversal_tag category;
  29. typedef Cons cons_type;
  30. typedef cons_iterator_identity<
  31. typename add_const<Cons>::type>
  32. identity;
  33. BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  34. explicit cons_iterator(cons_type& in_cons) BOOST_NOEXCEPT
  35. : cons(in_cons) {}
  36. cons_type& cons;
  37. private:
  38. // silence MSVC warning C4512: assignment operator could not be generated
  39. cons_iterator& operator= (cons_iterator const&);
  40. };
  41. struct nil_iterator : iterator_base<nil_iterator>
  42. {
  43. typedef forward_traversal_tag category;
  44. typedef cons_iterator_tag fusion_tag;
  45. typedef nil_ cons_type;
  46. typedef cons_iterator_identity<
  47. add_const<nil_>::type>
  48. identity;
  49. BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  50. nil_iterator() BOOST_NOEXCEPT {}
  51. BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  52. explicit nil_iterator(nil_ const&) BOOST_NOEXCEPT {}
  53. };
  54. template <>
  55. struct cons_iterator<nil_> : nil_iterator
  56. {
  57. BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  58. cons_iterator() BOOST_NOEXCEPT {}
  59. BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  60. explicit cons_iterator(nil_ const&) BOOST_NOEXCEPT {}
  61. };
  62. template <>
  63. struct cons_iterator<nil_ const> : nil_iterator
  64. {
  65. BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  66. cons_iterator() BOOST_NOEXCEPT {}
  67. BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  68. explicit cons_iterator(nil_ const&) BOOST_NOEXCEPT {}
  69. };
  70. template <>
  71. struct cons_iterator<list<> > : nil_iterator
  72. {
  73. BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  74. cons_iterator() BOOST_NOEXCEPT {}
  75. BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  76. explicit cons_iterator(nil_ const&) BOOST_NOEXCEPT {}
  77. };
  78. template <>
  79. struct cons_iterator<list<> const> : nil_iterator
  80. {
  81. BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  82. cons_iterator() BOOST_NOEXCEPT {}
  83. BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  84. explicit cons_iterator(nil_ const&) BOOST_NOEXCEPT {}
  85. };
  86. }}
  87. #ifdef BOOST_FUSION_WORKAROUND_FOR_LWG_2408
  88. namespace std
  89. {
  90. template <typename Cons>
  91. struct iterator_traits< ::boost::fusion::cons_iterator<Cons> >
  92. { };
  93. }
  94. #endif
  95. #endif