llvm-project/libcxx/include/__iterator/concepts.h

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// -*- C++ -*-
//===----------------------------------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef _LIBCPP___ITERATOR_CONCEPTS_H
#define _LIBCPP___ITERATOR_CONCEPTS_H
#include <__config>
#include <__iterator/incrementable_traits.h>
#include <__iterator/iter_move.h>
#include <__iterator/iterator_traits.h>
#include <__iterator/readable_traits.h>
#include <__memory/pointer_traits.h>
#include <__utility/forward.h>
#include <concepts>
#include <type_traits>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
_LIBCPP_BEGIN_NAMESPACE_STD
#if _LIBCPP_STD_VER > 17
// [iterator.concept.readable]
template<class _In>
concept __indirectly_readable_impl =
requires(const _In __i) {
typename iter_value_t<_In>;
typename iter_reference_t<_In>;
typename iter_rvalue_reference_t<_In>;
{ *__i } -> same_as<iter_reference_t<_In>>;
{ ranges::iter_move(__i) } -> same_as<iter_rvalue_reference_t<_In>>;
} &&
common_reference_with<iter_reference_t<_In>&&, iter_value_t<_In>&> &&
common_reference_with<iter_reference_t<_In>&&, iter_rvalue_reference_t<_In>&&> &&
common_reference_with<iter_rvalue_reference_t<_In>&&, const iter_value_t<_In>&>;
template<class _In>
concept indirectly_readable = __indirectly_readable_impl<remove_cvref_t<_In>>;
template<indirectly_readable _Tp>
using iter_common_reference_t = common_reference_t<iter_reference_t<_Tp>, iter_value_t<_Tp>&>;
// [iterator.concept.writable]
template<class _Out, class _Tp>
concept indirectly_writable =
requires(_Out&& __o, _Tp&& __t) {
*__o = _VSTD::forward<_Tp>(__t); // not required to be equality-preserving
*_VSTD::forward<_Out>(__o) = _VSTD::forward<_Tp>(__t); // not required to be equality-preserving
const_cast<const iter_reference_t<_Out>&&>(*__o) = _VSTD::forward<_Tp>(__t); // not required to be equality-preserving
const_cast<const iter_reference_t<_Out>&&>(*_VSTD::forward<_Out>(__o)) = _VSTD::forward<_Tp>(__t); // not required to be equality-preserving
};
// [iterator.concept.winc]
template<class _Tp>
concept __integer_like = integral<_Tp> && !same_as<_Tp, bool>;
template<class _Tp>
concept __signed_integer_like = signed_integral<_Tp>;
template<class _Ip>
concept weakly_incrementable =
// TODO: remove this once the clang bug is fixed (bugs.llvm.org/PR48173).
!same_as<_Ip, bool> && // Currently, clang does not handle bool correctly.
movable<_Ip> &&
requires(_Ip __i) {
typename iter_difference_t<_Ip>;
requires __signed_integer_like<iter_difference_t<_Ip>>;
{ ++__i } -> same_as<_Ip&>; // not required to be equality-preserving
__i++; // not required to be equality-preserving
};
// [iterator.concept.inc]
template<class _Ip>
concept incrementable =
regular<_Ip> &&
weakly_incrementable<_Ip> &&
requires(_Ip __i) {
{ __i++ } -> same_as<_Ip>;
};
// [iterator.concept.iterator]
template<class _Ip>
concept input_or_output_iterator =
requires(_Ip __i) {
{ *__i } -> __can_reference;
} &&
weakly_incrementable<_Ip>;
// [iterator.concept.sentinel]
template<class _Sp, class _Ip>
concept sentinel_for =
semiregular<_Sp> &&
input_or_output_iterator<_Ip> &&
__weakly_equality_comparable_with<_Sp, _Ip>;
template<class, class>
inline constexpr bool disable_sized_sentinel_for = false;
template<class _Sp, class _Ip>
concept sized_sentinel_for =
sentinel_for<_Sp, _Ip> &&
!disable_sized_sentinel_for<remove_cv_t<_Sp>, remove_cv_t<_Ip>> &&
requires(const _Ip& __i, const _Sp& __s) {
{ __s - __i } -> same_as<iter_difference_t<_Ip>>;
{ __i - __s } -> same_as<iter_difference_t<_Ip>>;
};
// [iterator.concept.input]
template<class _Ip>
concept input_iterator =
input_or_output_iterator<_Ip> &&
indirectly_readable<_Ip> &&
requires { typename _ITER_CONCEPT<_Ip>; } &&
derived_from<_ITER_CONCEPT<_Ip>, input_iterator_tag>;
// [iterator.concept.output]
template<class _Ip, class _Tp>
concept output_iterator =
input_or_output_iterator<_Ip> &&
indirectly_writable<_Ip, _Tp> &&
requires (_Ip __it, _Tp&& __t) {
*__it++ = _VSTD::forward<_Tp>(__t); // not required to be equality-preserving
};
// [iterator.concept.forward]
template<class _Ip>
concept forward_iterator =
input_iterator<_Ip> &&
derived_from<_ITER_CONCEPT<_Ip>, forward_iterator_tag> &&
incrementable<_Ip> &&
sentinel_for<_Ip, _Ip>;
// [iterator.concept.bidir]
template<class _Ip>
concept bidirectional_iterator =
forward_iterator<_Ip> &&
derived_from<_ITER_CONCEPT<_Ip>, bidirectional_iterator_tag> &&
requires(_Ip __i) {
{ --__i } -> same_as<_Ip&>;
{ __i-- } -> same_as<_Ip>;
};
template<class _Ip>
concept random_access_iterator =
bidirectional_iterator<_Ip> &&
derived_from<_ITER_CONCEPT<_Ip>, random_access_iterator_tag> &&
totally_ordered<_Ip> &&
sized_sentinel_for<_Ip, _Ip> &&
requires(_Ip __i, const _Ip __j, const iter_difference_t<_Ip> __n) {
{ __i += __n } -> same_as<_Ip&>;
{ __j + __n } -> same_as<_Ip>;
{ __n + __j } -> same_as<_Ip>;
{ __i -= __n } -> same_as<_Ip&>;
{ __j - __n } -> same_as<_Ip>;
{ __j[__n] } -> same_as<iter_reference_t<_Ip>>;
};
template<class _Ip>
concept contiguous_iterator =
random_access_iterator<_Ip> &&
derived_from<_ITER_CONCEPT<_Ip>, contiguous_iterator_tag> &&
is_lvalue_reference_v<iter_reference_t<_Ip>> &&
same_as<iter_value_t<_Ip>, remove_cvref_t<iter_reference_t<_Ip>>> &&
requires(const _Ip& __i) {
{ _VSTD::to_address(__i) } -> same_as<add_pointer_t<iter_reference_t<_Ip>>>;
};
template<class _Ip>
concept __has_arrow = input_iterator<_Ip> && (is_pointer_v<_Ip> || requires(_Ip __i) { __i.operator->(); });
// [indirectcallable.indirectinvocable]
template<class _Fp, class _It>
concept indirectly_unary_invocable =
indirectly_readable<_It> &&
copy_constructible<_Fp> &&
invocable<_Fp&, iter_value_t<_It>&> &&
invocable<_Fp&, iter_reference_t<_It>> &&
invocable<_Fp&, iter_common_reference_t<_It>> &&
common_reference_with<
invoke_result_t<_Fp&, iter_value_t<_It>&>,
invoke_result_t<_Fp&, iter_reference_t<_It>>>;
template<class _Fp, class _It>
concept indirectly_regular_unary_invocable =
indirectly_readable<_It> &&
copy_constructible<_Fp> &&
regular_invocable<_Fp&, iter_value_t<_It>&> &&
regular_invocable<_Fp&, iter_reference_t<_It>> &&
regular_invocable<_Fp&, iter_common_reference_t<_It>> &&
common_reference_with<
invoke_result_t<_Fp&, iter_value_t<_It>&>,
invoke_result_t<_Fp&, iter_reference_t<_It>>>;
template<class _Fp, class _It>
concept indirect_unary_predicate =
indirectly_readable<_It> &&
copy_constructible<_Fp> &&
predicate<_Fp&, iter_value_t<_It>&> &&
predicate<_Fp&, iter_reference_t<_It>> &&
predicate<_Fp&, iter_common_reference_t<_It>>;
template<class _Fp, class _It1, class _It2>
concept indirect_binary_predicate =
indirectly_readable<_It1> && indirectly_readable<_It2> &&
copy_constructible<_Fp> &&
predicate<_Fp&, iter_value_t<_It1>&, iter_value_t<_It2>&> &&
predicate<_Fp&, iter_value_t<_It1>&, iter_reference_t<_It2>> &&
predicate<_Fp&, iter_reference_t<_It1>, iter_value_t<_It2>&> &&
predicate<_Fp&, iter_reference_t<_It1>, iter_reference_t<_It2>> &&
predicate<_Fp&, iter_common_reference_t<_It1>, iter_common_reference_t<_It2>>;
template<class _Fp, class _It1, class _It2 = _It1>
concept indirect_equivalence_relation =
indirectly_readable<_It1> && indirectly_readable<_It2> &&
copy_constructible<_Fp> &&
equivalence_relation<_Fp&, iter_value_t<_It1>&, iter_value_t<_It2>&> &&
equivalence_relation<_Fp&, iter_value_t<_It1>&, iter_reference_t<_It2>> &&
equivalence_relation<_Fp&, iter_reference_t<_It1>, iter_value_t<_It2>&> &&
equivalence_relation<_Fp&, iter_reference_t<_It1>, iter_reference_t<_It2>> &&
equivalence_relation<_Fp&, iter_common_reference_t<_It1>, iter_common_reference_t<_It2>>;
template<class _Fp, class _It1, class _It2 = _It1>
concept indirect_strict_weak_order =
indirectly_readable<_It1> && indirectly_readable<_It2> &&
copy_constructible<_Fp> &&
strict_weak_order<_Fp&, iter_value_t<_It1>&, iter_value_t<_It2>&> &&
strict_weak_order<_Fp&, iter_value_t<_It1>&, iter_reference_t<_It2>> &&
strict_weak_order<_Fp&, iter_reference_t<_It1>, iter_value_t<_It2>&> &&
strict_weak_order<_Fp&, iter_reference_t<_It1>, iter_reference_t<_It2>> &&
strict_weak_order<_Fp&, iter_common_reference_t<_It1>, iter_common_reference_t<_It2>>;
template<class _Fp, class... _Its>
requires (indirectly_readable<_Its> && ...) && invocable<_Fp, iter_reference_t<_Its>...>
using indirect_result_t = invoke_result_t<_Fp, iter_reference_t<_Its>...>;
template<class _In, class _Out>
concept indirectly_movable =
indirectly_readable<_In> &&
indirectly_writable<_Out, iter_rvalue_reference_t<_In>>;
template<class _In, class _Out>
concept indirectly_movable_storable =
indirectly_movable<_In, _Out> &&
indirectly_writable<_Out, iter_value_t<_In>> &&
movable<iter_value_t<_In>> &&
constructible_from<iter_value_t<_In>, iter_rvalue_reference_t<_In>> &&
assignable_from<iter_value_t<_In>&, iter_rvalue_reference_t<_In>>;
template<class _In, class _Out>
concept indirectly_copyable =
indirectly_readable<_In> &&
indirectly_writable<_Out, iter_reference_t<_In>>;
template<class _In, class _Out>
concept indirectly_copyable_storable =
indirectly_copyable<_In, _Out> &&
indirectly_writable<_Out, iter_value_t<_In>&> &&
indirectly_writable<_Out, const iter_value_t<_In>&> &&
indirectly_writable<_Out, iter_value_t<_In>&&> &&
indirectly_writable<_Out, const iter_value_t<_In>&&> &&
copyable<iter_value_t<_In>> &&
constructible_from<iter_value_t<_In>, iter_reference_t<_In>> &&
assignable_from<iter_value_t<_In>&, iter_reference_t<_In>>;
// Note: indirectly_swappable is located in iter_swap.h to prevent a dependency cycle
// (both iter_swap and indirectly_swappable require indirectly_readable).
#endif // _LIBCPP_STD_VER > 17
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___ITERATOR_CONCEPTS_H