libcxx/include/__iterator/cpp17_iterator_concepts.h

   1 //===----------------------------------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #ifndef _LIBCPP___ITERATOR_CPP17_ITERATOR_CONCEPTS_H
  10 #define _LIBCPP___ITERATOR_CPP17_ITERATOR_CONCEPTS_H
  11
  12 #include <__concepts/boolean_testable.h>
  13 #include <__concepts/convertible_to.h>
  14 #include <__concepts/same_as.h>
  15 #include <__config>
  16 #include <__iterator/iterator_traits.h>
  17 #include <__type_traits/is_convertible.h>
  18 #include <__type_traits/is_copy_constructible.h>
  19 #include <__type_traits/is_default_constructible.h>
  20 #include <__type_traits/is_move_constructible.h>
  21 #include <__type_traits/is_signed.h>
  22 #include <__type_traits/is_void.h>
  23 #include <__utility/as_const.h>
  24 #include <__utility/forward.h>
  25 #include <__utility/move.h>
  26 #include <__utility/swap.h>
  27
  28 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  29 #  pragma GCC system_header
  30 #endif
  31
  32 #if _LIBCPP_STD_VER >= 20
  33
  34 _LIBCPP_BEGIN_NAMESPACE_STD
  35
  36 template <class _Tp>
  37 concept __cpp17_move_constructible = is_move_constructible_v<_Tp>;
  38
  39 template <class _Tp>
  40 concept __cpp17_copy_constructible = __cpp17_move_constructible<_Tp> && is_copy_constructible_v<_Tp>;
  41
  42 template <class _Tp>
  43 concept __cpp17_move_assignable = requires(_Tp __lhs, _Tp __rhs) {
  44   { __lhs = std::move(__rhs) } -> same_as<_Tp&>;
  45 };
  46
  47 template <class _Tp>
  48 concept __cpp17_copy_assignable = __cpp17_move_assignable<_Tp> && requires(_Tp __lhs, _Tp __rhs) {
  49   { __lhs = __rhs } -> same_as<_Tp&>;
  50   { __lhs = std::as_const(__rhs) } -> same_as<_Tp&>;
  51 };
  52
  53 template <class _Tp>
  54 concept __cpp17_destructible = requires(_Tp __v) { __v.~_Tp(); };
  55
  56 template <class _Tp>
  57 concept __cpp17_equality_comparable = requires(_Tp __lhs, _Tp __rhs) {
  58   { __lhs == __rhs } -> __boolean_testable;
  59   { std::as_const(__lhs) == __rhs } -> __boolean_testable;
  60   { __lhs == std::as_const(__rhs) } -> __boolean_testable;
  61   { std::as_const(__lhs) == std::as_const(__rhs) } -> __boolean_testable;
  62 };
  63
  64 template <class _Tp>
  65 concept __cpp17_default_constructible = is_default_constructible_v<_Tp>;
  66
  67 template <class _Iter>
  68 concept __cpp17_iterator =
  69     __cpp17_copy_constructible<_Iter> && __cpp17_copy_assignable<_Iter> && __cpp17_destructible<_Iter> &&
  70     (is_signed_v<__iter_diff_t<_Iter>> || is_void_v<__iter_diff_t<_Iter>>)&&requires(_Iter __iter) {
  71       { *__iter };
  72       { ++__iter } -> same_as<_Iter&>;
  73     };
  74
  75 template <class _Iter>
  76 concept __cpp17_input_iterator =
  77     __cpp17_iterator<_Iter> && __cpp17_equality_comparable<_Iter> && requires(_Iter __lhs, _Iter __rhs) {
  78       { __lhs != __rhs } -> __boolean_testable;
  79       { std::as_const(__lhs) != __rhs } -> __boolean_testable;
  80       { __lhs != std::as_const(__rhs) } -> __boolean_testable;
  81       { std::as_const(__lhs) != std::as_const(__rhs) } -> __boolean_testable;
  82
  83       { *__lhs } -> same_as<__iter_reference<_Iter>>;
  84       { *std::as_const(__lhs) } -> same_as<__iter_reference<_Iter>>;
  85
  86       { ++__lhs } -> same_as<_Iter&>;
  87       { (void)__lhs++ };
  88       { *__lhs++ };
  89     };
  90
  91 template <class _Iter, class _WriteTo>
  92 concept __cpp17_output_iterator = __cpp17_iterator<_Iter> && requires(_Iter __iter, _WriteTo __write) {
  93   { *__iter = std::forward<_WriteTo>(__write) };
  94   { ++__iter } -> same_as<_Iter&>;
  95   { __iter++ } -> convertible_to<const _Iter&>;
  96   { *__iter++ = std::forward<_WriteTo>(__write) };
  97 };
  98
  99 template <class _Iter>
 100 concept __cpp17_forward_iterator =
 101     __cpp17_input_iterator<_Iter> && __cpp17_default_constructible<_Iter> && requires(_Iter __iter) {
 102       { __iter++ } -> convertible_to<const _Iter&>;
 103       { *__iter++ } -> same_as<__iter_reference<_Iter>>;
 104     };
 105
 106 template <class _Iter>
 107 concept __cpp17_bidirectional_iterator = __cpp17_forward_iterator<_Iter> && requires(_Iter __iter) {
 108   { --__iter } -> same_as<_Iter&>;
 109   { __iter-- } -> convertible_to<const _Iter&>;
 110   { *__iter-- } -> same_as<__iter_reference<_Iter>>;
 111 };
 112
 113 template <class _Iter>
 114 concept __cpp17_random_access_iterator =
 115     __cpp17_bidirectional_iterator<_Iter> && requires(_Iter __iter, __iter_diff_t<_Iter> __n) {
 116       { __iter += __n } -> same_as<_Iter&>;
 117
 118       { __iter + __n } -> same_as<_Iter>;
 119       { __n + __iter } -> same_as<_Iter>;
 120       { std::as_const(__iter) + __n } -> same_as<_Iter>;
 121       { __n + std::as_const(__iter) } -> same_as<_Iter>;
 122
 123       { __iter -= __n } -> same_as<_Iter&>;
 124       { __iter - __n } -> same_as<_Iter>;
 125       { std::as_const(__iter) - __n } -> same_as<_Iter>;
 126
 127       { __iter - __iter } -> same_as<__iter_diff_t<_Iter>>;
 128       { std::as_const(__iter) - __iter } -> same_as<__iter_diff_t<_Iter>>;
 129       { __iter - std::as_const(__iter) } -> same_as<__iter_diff_t<_Iter>>;
 130       { std::as_const(__iter) - std::as_const(__iter) } -> same_as<__iter_diff_t<_Iter>>;
 131
 132       { __iter[__n] } -> convertible_to<__iter_reference<_Iter>>;
 133       { std::as_const(__iter)[__n] } -> convertible_to<__iter_reference<_Iter>>;
 134
 135       { __iter < __iter } -> __boolean_testable;
 136       { std::as_const(__iter) < __iter } -> __boolean_testable;
 137       { __iter < std::as_const(__iter) } -> __boolean_testable;
 138       { std::as_const(__iter) < std::as_const(__iter) } -> __boolean_testable;
 139
 140       { __iter > __iter } -> __boolean_testable;
 141       { std::as_const(__iter) > __iter } -> __boolean_testable;
 142       { __iter > std::as_const(__iter) } -> __boolean_testable;
 143       { std::as_const(__iter) > std::as_const(__iter) } -> __boolean_testable;
 144
 145       { __iter >= __iter } -> __boolean_testable;
 146       { std::as_const(__iter) >= __iter } -> __boolean_testable;
 147       { __iter >= std::as_const(__iter) } -> __boolean_testable;
 148       { std::as_const(__iter) >= std::as_const(__iter) } -> __boolean_testable;
 149
 150       { __iter <= __iter } -> __boolean_testable;
 151       { std::as_const(__iter) <= __iter } -> __boolean_testable;
 152       { __iter <= std::as_const(__iter) } -> __boolean_testable;
 153       { std::as_const(__iter) <= std::as_const(__iter) } -> __boolean_testable;
 154     };
 155
 156 _LIBCPP_END_NAMESPACE_STD
 157
 158 #  ifndef _LIBCPP_DISABLE_ITERATOR_CHECKS
 159 #    define _LIBCPP_REQUIRE_CPP17_INPUT_ITERATOR(iter_t) static_assert(::std::__cpp17_input_iterator<iter_t>);
 160 #    define _LIBCPP_REQUIRE_CPP17_OUTPUT_ITERATOR(iter_t, write_t)                                                     \
 161       static_assert(::std::__cpp17_output_iterator<iter_t, write_t>);
 162 #    define _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(iter_t) static_assert(::std::__cpp17_forward_iterator<iter_t>);
 163 #    define _LIBCPP_REQUIRE_CPP17_BIDIRECTIONAL_ITERATOR(iter_t)                                                       \
 164       static_assert(::std::__cpp17_bidirectional_iterator<iter_t>);
 165 #    define _LIBCPP_REQUIRE_CPP17_RANDOM_ACCESS_ITERATOR(iter_t)                                                       \
 166       static_assert(::std::__cpp17_random_access_iterator<iter_t>);
 167 #  else
 168 #    define _LIBCPP_REQUIRE_CPP17_INPUT_ITERATOR(iter_t)
 169 #    define _LIBCPP_REQUIRE_CPP17_OUTPUT_ITERATOR(iter_t, write_t)
 170 #    define _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(iter_t)
 171 #    define _LIBCPP_REQUIRE_CPP17_BIDIRECTIONAL_ITERATOR(iter_t)
 172 #    define _LIBCPP_REQUIRE_CPP17_RANDOM_ACCESS_ITERATOR(iter_t)
 173 #  endif
 174
 175 #else // _LIBCPP_STD_VER >= 20
 176
 177 #  define _LIBCPP_REQUIRE_CPP17_INPUT_ITERATOR(iter_t)
 178 #  define _LIBCPP_REQUIRE_CPP17_OUTPUT_ITERATOR(iter_t, write_t)
 179 #  define _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(iter_t)
 180 #  define _LIBCPP_REQUIRE_CPP17_BIDIRECTIONAL_ITERATOR(iter_t)
 181 #  define _LIBCPP_REQUIRE_CPP17_RANDOM_ACCESS_ITERATOR(iter_t)
 182
 183 #endif // _LIBCPP_STD_VER >= 20
 184
 185 #endif // _LIBCPP___ITERATOR_CPP17_ITERATOR_CONCEPTS_H