fusion_iterator.hpp 2.5 KB

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  1. /*=============================================================================
  2. Copyright (c) 2001-2011 Joel de Guzman
  3. Distributed under the Boost Software License, Version 1.0. (See accompanying
  4. file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
  5. ==============================================================================*/
  6. #if !defined(FUSION_FUSION_ITERATOR_10012005_1551)
  7. #define FUSION_FUSION_ITERATOR_10012005_1551
  8. #include <boost/fusion/support/config.hpp>
  9. #include <boost/fusion/iterator/value_of.hpp>
  10. #include <boost/fusion/iterator/next.hpp>
  11. #include <boost/fusion/iterator/prior.hpp>
  12. #include <boost/fusion/iterator/advance.hpp>
  13. #include <boost/fusion/iterator/distance.hpp>
  14. #include <boost/fusion/support/category_of.hpp>
  15. #include <boost/mpl/next_prior.hpp>
  16. #include <boost/mpl/advance_fwd.hpp>
  17. #include <boost/mpl/distance_fwd.hpp>
  18. #include <boost/mpl/iterator_tags.hpp>
  19. #include <boost/mpl/eval_if.hpp>
  20. #include <boost/type_traits/is_base_of.hpp>
  21. namespace boost { namespace fusion { namespace detail
  22. {
  23. template<class Category>
  24. struct to_mpl_category {
  25. typedef typename mpl::eval_if<
  26. is_base_of<random_access_traversal_tag, Category>,
  27. mpl::random_access_iterator_tag,
  28. mpl::eval_if<
  29. is_base_of<bidirectional_traversal_tag, Category>,
  30. mpl::bidirectional_iterator_tag,
  31. mpl::forward_iterator_tag
  32. >
  33. >::type type;
  34. };
  35. }}}
  36. namespace boost { namespace mpl
  37. {
  38. template <typename Iterator>
  39. struct fusion_iterator
  40. {
  41. typedef typename fusion::result_of::value_of<Iterator>::type type;
  42. typedef typename fusion::traits::category_of<Iterator>::type fusion_category;
  43. typedef typename fusion::detail::to_mpl_category<fusion_category>::type category;
  44. typedef Iterator iterator;
  45. };
  46. template <typename Iterator>
  47. struct next<fusion_iterator<Iterator> >
  48. {
  49. typedef fusion_iterator<typename fusion::result_of::next<Iterator>::type> type;
  50. };
  51. template <typename Iterator>
  52. struct prior<fusion_iterator<Iterator> >
  53. {
  54. typedef fusion_iterator<typename fusion::result_of::prior<Iterator>::type> type;
  55. };
  56. template <typename Iterator, typename N>
  57. struct advance<fusion_iterator<Iterator>, N>
  58. {
  59. typedef fusion_iterator<typename fusion::result_of::advance<Iterator, N>::type> type;
  60. };
  61. template <typename First, typename Last>
  62. struct distance<fusion_iterator<First>, fusion_iterator<Last> >
  63. : fusion::result_of::distance<First, Last>
  64. {};
  65. }}
  66. #endif