concepts.h 4.3 KB

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  1. // -*- C++ -*-
  2. //===----------------------------------------------------------------------===//
  3. //
  4. // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
  5. // See https://llvm.org/LICENSE.txt for license information.
  6. // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
  7. //
  8. //===----------------------------------------------------------------------===//
  9. #ifndef _LIBCPP___RANGES_CONCEPTS_H
  10. #define _LIBCPP___RANGES_CONCEPTS_H
  11. #include <__concepts/constructible.h>
  12. #include <__concepts/movable.h>
  13. #include <__concepts/same_as.h>
  14. #include <__config>
  15. #include <__iterator/concepts.h>
  16. #include <__iterator/incrementable_traits.h>
  17. #include <__iterator/iter_move.h>
  18. #include <__iterator/iterator_traits.h>
  19. #include <__iterator/readable_traits.h>
  20. #include <__ranges/access.h>
  21. #include <__ranges/data.h>
  22. #include <__ranges/enable_borrowed_range.h>
  23. #include <__ranges/enable_view.h>
  24. #include <__ranges/size.h>
  25. #include <initializer_list>
  26. #include <type_traits>
  27. #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  28. # pragma GCC system_header
  29. #endif
  30. _LIBCPP_BEGIN_NAMESPACE_STD
  31. #if !defined(_LIBCPP_HAS_NO_CONCEPTS)
  32. namespace ranges {
  33. // [range.range]
  34. template <class _Tp>
  35. concept range = requires(_Tp& __t) {
  36. ranges::begin(__t); // sometimes equality-preserving
  37. ranges::end(__t);
  38. };
  39. template <class _Tp>
  40. concept input_range = range<_Tp> && input_iterator<iterator_t<_Tp>>;
  41. template<class _Range>
  42. concept borrowed_range = range<_Range> &&
  43. (is_lvalue_reference_v<_Range> || enable_borrowed_range<remove_cvref_t<_Range>>);
  44. // `iterator_t` defined in <__ranges/access.h>
  45. template <range _Rp>
  46. using sentinel_t = decltype(ranges::end(declval<_Rp&>()));
  47. template <range _Rp>
  48. using range_difference_t = iter_difference_t<iterator_t<_Rp>>;
  49. template <range _Rp>
  50. using range_value_t = iter_value_t<iterator_t<_Rp>>;
  51. template <range _Rp>
  52. using range_reference_t = iter_reference_t<iterator_t<_Rp>>;
  53. template <range _Rp>
  54. using range_rvalue_reference_t = iter_rvalue_reference_t<iterator_t<_Rp>>;
  55. #if !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
  56. // [range.sized]
  57. template <class _Tp>
  58. concept sized_range = range<_Tp> && requires(_Tp& __t) { ranges::size(__t); };
  59. template<sized_range _Rp>
  60. using range_size_t = decltype(ranges::size(declval<_Rp&>()));
  61. // `disable_sized_range` defined in `<__ranges/size.h>`
  62. // [range.view], views
  63. // `enable_view` defined in <__ranges/enable_view.h>
  64. // `view_base` defined in <__ranges/enable_view.h>
  65. template <class _Tp>
  66. concept view =
  67. range<_Tp> &&
  68. movable<_Tp> &&
  69. enable_view<_Tp>;
  70. template <class _Range>
  71. concept __simple_view =
  72. view<_Range> && range<const _Range> &&
  73. same_as<iterator_t<_Range>, iterator_t<const _Range>> &&
  74. same_as<sentinel_t<_Range>, sentinel_t<const _Range>>;
  75. // [range.refinements], other range refinements
  76. template <class _Rp, class _Tp>
  77. concept output_range = range<_Rp> && output_iterator<iterator_t<_Rp>, _Tp>;
  78. template <class _Tp>
  79. concept forward_range = input_range<_Tp> && forward_iterator<iterator_t<_Tp>>;
  80. template <class _Tp>
  81. concept bidirectional_range = forward_range<_Tp> && bidirectional_iterator<iterator_t<_Tp>>;
  82. template <class _Tp>
  83. concept random_access_range =
  84. bidirectional_range<_Tp> && random_access_iterator<iterator_t<_Tp>>;
  85. template<class _Tp>
  86. concept contiguous_range =
  87. random_access_range<_Tp> &&
  88. contiguous_iterator<iterator_t<_Tp>> &&
  89. requires(_Tp& __t) {
  90. { ranges::data(__t) } -> same_as<add_pointer_t<range_reference_t<_Tp>>>;
  91. };
  92. template <class _Tp>
  93. concept common_range = range<_Tp> && same_as<iterator_t<_Tp>, sentinel_t<_Tp>>;
  94. template <class _Tp>
  95. inline constexpr bool __is_std_initializer_list = false;
  96. template <class _Ep>
  97. inline constexpr bool __is_std_initializer_list<initializer_list<_Ep>> = true;
  98. template <class _Tp>
  99. concept viewable_range =
  100. range<_Tp> &&
  101. ((view<remove_cvref_t<_Tp>> && constructible_from<remove_cvref_t<_Tp>, _Tp>) ||
  102. (!view<remove_cvref_t<_Tp>> &&
  103. (is_lvalue_reference_v<_Tp> ||
  104. (movable<remove_reference_t<_Tp>> && !__is_std_initializer_list<remove_cvref_t<_Tp>>))));
  105. #endif // !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
  106. } // namespace ranges
  107. #endif // !defined(_LIBCPP_HAS_NO_CONCEPTS)
  108. _LIBCPP_END_NAMESPACE_STD
  109. #endif // _LIBCPP___RANGES_CONCEPTS_H