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_constructible.h>
  18 #include <__type_traits/is_convertible.h>
  19 #include <__type_traits/is_signed.h>
  20 #include <__type_traits/is_void.h>
  21 #include <__utility/as_const.h>
  22 #include <__utility/forward.h>
  23 #include <__utility/move.h>
  24 #include <__utility/swap.h>
  25
  26 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  27 #  pragma GCC system_header
  28 #endif
  29
  30 _LIBCPP_PUSH_MACROS
  31 #include <__undef_macros>
  32
  33 #if _LIBCPP_STD_VER >= 20
  34
  35 _LIBCPP_BEGIN_NAMESPACE_STD
  36
  37 template <class _Tp>
  38 concept __cpp17_move_constructible = is_move_constructible_v<_Tp>;
  39
  40 template <class _Tp>
  41 concept __cpp17_copy_constructible = __cpp17_move_constructible<_Tp> && is_copy_constructible_v<_Tp>;
  42
  43 template <class _Tp>
  44 concept __cpp17_move_assignable = requires(_Tp __lhs, _Tp __rhs) {
  45   { __lhs = std::move(__rhs) } -> same_as<_Tp&>;
  46 };
  47
  48 template <class _Tp>
  49 concept __cpp17_copy_assignable = __cpp17_move_assignable<_Tp> && requires(_Tp __lhs, _Tp __rhs) {
  50   { __lhs = __rhs } -> same_as<_Tp&>;
  51   { __lhs = std::as_const(__rhs) } -> same_as<_Tp&>;
  52 };
  53
  54 template <class _Tp>
  55 concept __cpp17_destructible = requires(_Tp __v) { __v.~_Tp(); };
  56
  57 template <class _Tp>
  58 concept __cpp17_equality_comparable = requires(_Tp __lhs, _Tp __rhs) {
  59   { __lhs == __rhs } -> __boolean_testable;
  60   { std::as_const(__lhs) == __rhs } -> __boolean_testable;
  61   { __lhs == std::as_const(__rhs) } -> __boolean_testable;
  62   { std::as_const(__lhs) == std::as_const(__rhs) } -> __boolean_testable;
  63 };
  64
  65 template <class _Tp>
  66 concept __cpp17_default_constructible = is_default_constructible_v<_Tp>;
  67
  68 template <class _Iter>
  69 concept __cpp17_iterator =
  70     __cpp17_copy_constructible<_Iter> && __cpp17_copy_assignable<_Iter> && __cpp17_destructible<_Iter> &&
  71     (is_signed_v<__iter_diff_t<_Iter>> || is_void_v<__iter_diff_t<_Iter>>) && requires(_Iter __iter) {
  72       { *__iter };
  73       { ++__iter } -> same_as<_Iter&>;
  74     };
  75
  76 template <class _Iter>
  77 concept __cpp17_input_iterator =
  78     __cpp17_iterator<_Iter> && __cpp17_equality_comparable<_Iter> && requires(_Iter __lhs, _Iter __rhs) {
  79       { __lhs != __rhs } -> __boolean_testable;
  80       { std::as_const(__lhs) != __rhs } -> __boolean_testable;
  81       { __lhs != std::as_const(__rhs) } -> __boolean_testable;
  82       { std::as_const(__lhs) != std::as_const(__rhs) } -> __boolean_testable;
  83
  84       { *__lhs } -> same_as<__iter_reference<_Iter>>;
  85       { *std::as_const(__lhs) } -> same_as<__iter_reference<_Iter>>;
  86
  87       { ++__lhs } -> same_as<_Iter&>;
  88       { (void)__lhs++ };
  89       { *__lhs++ };
  90     };
  91
  92 template <class _Iter, class _WriteTo>
  93 concept __cpp17_output_iterator = __cpp17_iterator<_Iter> && requires(_Iter __iter, _WriteTo __write) {
  94   { *__iter = std::forward<_WriteTo>(__write) };
  95   { ++__iter } -> same_as<_Iter&>;
  96   { __iter++ } -> convertible_to<const _Iter&>;
  97   { *__iter++ = std::forward<_WriteTo>(__write) };
  98 };
  99
 100 template <class _Iter>
 101 concept __cpp17_forward_iterator =
 102     __cpp17_input_iterator<_Iter> && __cpp17_default_constructible<_Iter> && requires(_Iter __iter) {
 103       { __iter++ } -> convertible_to<const _Iter&>;
 104       { *__iter++ } -> same_as<__iter_reference<_Iter>>;
 105     };
 106
 107 template <class _Iter>
 108 concept __cpp17_bidirectional_iterator = __cpp17_forward_iterator<_Iter> && requires(_Iter __iter) {
 109   { --__iter } -> same_as<_Iter&>;
 110   { __iter-- } -> convertible_to<const _Iter&>;
 111   { *__iter-- } -> same_as<__iter_reference<_Iter>>;
 112 };
 113
 114 template <class _Iter>
 115 concept __cpp17_random_access_iterator =
 116     __cpp17_bidirectional_iterator<_Iter> && requires(_Iter __iter, __iter_diff_t<_Iter> __n) {
 117       { __iter += __n } -> same_as<_Iter&>;
 118
 119       { __iter + __n } -> same_as<_Iter>;
 120       { __n + __iter } -> same_as<_Iter>;
 121       { std::as_const(__iter) + __n } -> same_as<_Iter>;
 122       { __n + std::as_const(__iter) } -> same_as<_Iter>;
 123
 124       { __iter -= __n } -> same_as<_Iter&>;
 125       { __iter - __n } -> same_as<_Iter>;
 126       { std::as_const(__iter) - __n } -> same_as<_Iter>;
 127
 128       { __iter - __iter } -> same_as<__iter_diff_t<_Iter>>;
 129       { std::as_const(__iter) - __iter } -> same_as<__iter_diff_t<_Iter>>;
 130       { __iter - std::as_const(__iter) } -> same_as<__iter_diff_t<_Iter>>;
 131       { std::as_const(__iter) - std::as_const(__iter) } -> same_as<__iter_diff_t<_Iter>>;
 132
 133       { __iter[__n] } -> convertible_to<__iter_reference<_Iter>>;
 134       { std::as_const(__iter)[__n] } -> convertible_to<__iter_reference<_Iter>>;
 135
 136       { __iter < __iter } -> __boolean_testable;
 137       { std::as_const(__iter) < __iter } -> __boolean_testable;
 138       { __iter < std::as_const(__iter) } -> __boolean_testable;
 139       { std::as_const(__iter) < std::as_const(__iter) } -> __boolean_testable;
 140
 141       { __iter > __iter } -> __boolean_testable;
 142       { std::as_const(__iter) > __iter } -> __boolean_testable;
 143       { __iter > std::as_const(__iter) } -> __boolean_testable;
 144       { std::as_const(__iter) > std::as_const(__iter) } -> __boolean_testable;
 145
 146       { __iter >= __iter } -> __boolean_testable;
 147       { std::as_const(__iter) >= __iter } -> __boolean_testable;
 148       { __iter >= std::as_const(__iter) } -> __boolean_testable;
 149       { std::as_const(__iter) >= std::as_const(__iter) } -> __boolean_testable;
 150
 151       { __iter <= __iter } -> __boolean_testable;
 152       { std::as_const(__iter) <= __iter } -> __boolean_testable;
 153       { __iter <= std::as_const(__iter) } -> __boolean_testable;
 154       { std::as_const(__iter) <= std::as_const(__iter) } -> __boolean_testable;
 155     };
 156
 157 _LIBCPP_END_NAMESPACE_STD
 158
 159 #  ifndef _LIBCPP_DISABLE_ITERATOR_CHECKS
 160 #    define _LIBCPP_REQUIRE_CPP17_INPUT_ITERATOR(iter_t, message)                                                      \
 161       static_assert(::std::__cpp17_input_iterator<iter_t>, message)
 162 #    define _LIBCPP_REQUIRE_CPP17_OUTPUT_ITERATOR(iter_t, write_t, message)                                            \
 163       static_assert(::std::__cpp17_output_iterator<iter_t, write_t>, message)
 164 #    define _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(iter_t, message)                                                    \
 165       static_assert(::std::__cpp17_forward_iterator<iter_t>, message)
 166 #    define _LIBCPP_REQUIRE_CPP17_BIDIRECTIONAL_ITERATOR(iter_t, message)                                              \
 167       static_assert(::std::__cpp17_bidirectional_iterator<iter_t>, message)
 168 #    define _LIBCPP_REQUIRE_CPP17_RANDOM_ACCESS_ITERATOR(iter_t, message)                                              \
 169       static_assert(::std::__cpp17_random_access_iterator<iter_t>, message)
 170 #  else
 171 #    define _LIBCPP_REQUIRE_CPP17_INPUT_ITERATOR(iter_t, message) static_assert(true)
 172 #    define _LIBCPP_REQUIRE_CPP17_OUTPUT_ITERATOR(iter_t, write_t, message) static_assert(true)
 173 #    define _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(iter_t, message) static_assert(true)
 174 #    define _LIBCPP_REQUIRE_CPP17_BIDIRECTIONAL_ITERATOR(iter_t, message) static_assert(true)
 175 #    define _LIBCPP_REQUIRE_CPP17_RANDOM_ACCESS_ITERATOR(iter_t, message) static_assert(true)
 176 #  endif
 177
 178 #else // _LIBCPP_STD_VER >= 20
 179
 180 #  define _LIBCPP_REQUIRE_CPP17_INPUT_ITERATOR(iter_t, message) static_assert(true)
 181 #  define _LIBCPP_REQUIRE_CPP17_OUTPUT_ITERATOR(iter_t, write_t, message) static_assert(true)
 182 #  define _LIBCPP_REQUIRE_CPP17_FORWARD_ITERATOR(iter_t, message) static_assert(true)
 183 #  define _LIBCPP_REQUIRE_CPP17_BIDIRECTIONAL_ITERATOR(iter_t, message) static_assert(true)
 184 #  define _LIBCPP_REQUIRE_CPP17_RANDOM_ACCESS_ITERATOR(iter_t, message) static_assert(true)
 185
 186 #endif // _LIBCPP_STD_VER >= 20
 187
 188 _LIBCPP_POP_MACROS
 189
 190 #endif // _LIBCPP___ITERATOR_CPP17_ITERATOR_CONCEPTS_H