erase.hpp 5.0 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140
  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_ERASE_07232005_0534)
  7. #define FUSION_ERASE_07232005_0534
  8. #include <boost/fusion/support/config.hpp>
  9. #include <boost/fusion/iterator/equal_to.hpp>
  10. #include <boost/fusion/iterator/mpl/convert_iterator.hpp>
  11. #include <boost/fusion/view/joint_view/joint_view.hpp>
  12. #include <boost/fusion/view/iterator_range/iterator_range.hpp>
  13. #include <boost/fusion/support/detail/as_fusion_element.hpp>
  14. #include <boost/fusion/sequence/intrinsic/begin.hpp>
  15. #include <boost/fusion/sequence/intrinsic/end.hpp>
  16. #include <boost/fusion/adapted/mpl/mpl_iterator.hpp>
  17. #include <boost/fusion/support/is_sequence.hpp>
  18. #include <boost/utility/enable_if.hpp>
  19. #include <boost/mpl/if.hpp>
  20. namespace boost { namespace fusion
  21. {
  22. namespace result_of
  23. {
  24. template <typename Sequence, typename First>
  25. struct compute_erase_last // put this in detail!!!
  26. {
  27. typedef typename result_of::end<Sequence>::type seq_last_type;
  28. typedef typename convert_iterator<First>::type first_type;
  29. typedef typename
  30. mpl::if_<
  31. result_of::equal_to<first_type, seq_last_type>
  32. , first_type
  33. , typename result_of::next<first_type>::type
  34. >::type
  35. type;
  36. BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  37. static type
  38. call(First const& first, mpl::false_)
  39. {
  40. return fusion::next(convert_iterator<First>::call(first));
  41. }
  42. BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  43. static type
  44. call(First const& first, mpl::true_)
  45. {
  46. return convert_iterator<First>::call(first);
  47. }
  48. BOOST_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  49. static type
  50. call(First const& first)
  51. {
  52. return call(first, result_of::equal_to<first_type, seq_last_type>());
  53. }
  54. };
  55. struct use_default;
  56. template <class T, class Default>
  57. struct fusion_default_help
  58. : mpl::if_<
  59. is_same<T, use_default>
  60. , Default
  61. , T
  62. >
  63. {
  64. };
  65. template <
  66. typename Sequence
  67. , typename First
  68. , typename Last = use_default>
  69. struct erase
  70. {
  71. typedef typename result_of::begin<Sequence>::type seq_first_type;
  72. typedef typename result_of::end<Sequence>::type seq_last_type;
  73. BOOST_STATIC_ASSERT((!result_of::equal_to<seq_first_type, seq_last_type>::value));
  74. typedef First FirstType;
  75. typedef typename
  76. fusion_default_help<
  77. Last
  78. , typename compute_erase_last<Sequence, First>::type
  79. >::type
  80. LastType;
  81. typedef typename convert_iterator<FirstType>::type first_type;
  82. typedef typename convert_iterator<LastType>::type last_type;
  83. typedef iterator_range<seq_first_type, first_type> left_type;
  84. typedef iterator_range<last_type, seq_last_type> right_type;
  85. typedef joint_view<left_type, right_type> type;
  86. };
  87. }
  88. template <typename Sequence, typename First>
  89. BOOST_CXX14_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  90. inline typename
  91. lazy_enable_if<
  92. traits::is_sequence<Sequence>
  93. , typename result_of::erase<Sequence const, First>
  94. >::type
  95. erase(Sequence const& seq, First const& first)
  96. {
  97. typedef result_of::erase<Sequence const, First> result_of;
  98. typedef typename result_of::left_type left_type;
  99. typedef typename result_of::right_type right_type;
  100. typedef typename result_of::type result_type;
  101. left_type left(
  102. fusion::begin(seq)
  103. , convert_iterator<First>::call(first));
  104. right_type right(
  105. fusion::result_of::compute_erase_last<Sequence const, First>::call(first)
  106. , fusion::end(seq));
  107. return result_type(left, right);
  108. }
  109. template <typename Sequence, typename First, typename Last>
  110. BOOST_CXX14_CONSTEXPR BOOST_FUSION_GPU_ENABLED
  111. inline typename result_of::erase<Sequence const, First, Last>::type
  112. erase(Sequence const& seq, First const& first, Last const& last)
  113. {
  114. typedef result_of::erase<Sequence const, First, Last> result_of;
  115. typedef typename result_of::left_type left_type;
  116. typedef typename result_of::right_type right_type;
  117. typedef typename result_of::type result_type;
  118. left_type left(fusion::begin(seq), first);
  119. right_type right(last, fusion::end(seq));
  120. return result_type(left, right);
  121. }
  122. }}
  123. #endif