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- // <ranges> -*- C++ -*-
- // Copyright (C) 2019-2022 Free Software Foundation, Inc.
- //
- // This file is part of the GNU ISO C++ Library. This library is free
- // software; you can redistribute it and/or modify it under the
- // terms of the GNU General Public License as published by the
- // Free Software Foundation; either version 3, or (at your option)
- // any later version.
- // This library is distributed in the hope that it will be useful,
- // but WITHOUT ANY WARRANTY; without even the implied warranty of
- // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- // GNU General Public License for more details.
- // Under Section 7 of GPL version 3, you are granted additional
- // permissions described in the GCC Runtime Library Exception, version
- // 3.1, as published by the Free Software Foundation.
- // You should have received a copy of the GNU General Public License and
- // a copy of the GCC Runtime Library Exception along with this program;
- // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
- // <http://www.gnu.org/licenses/>.
- /** @file include/ranges
- * This is a Standard C++ Library header.
- * @ingroup concepts
- */
- #ifndef _GLIBCXX_RANGES
- #define _GLIBCXX_RANGES 1
- #if __cplusplus > 201703L
- #pragma GCC system_header
- #include <concepts>
- #if __cpp_lib_concepts
- #include <compare>
- #include <initializer_list>
- #include <iterator>
- #include <optional>
- #include <span>
- #include <tuple>
- #include <bits/ranges_util.h>
- #include <bits/refwrap.h>
- /**
- * @defgroup ranges Ranges
- *
- * Components for dealing with ranges of elements.
- */
- namespace std _GLIBCXX_VISIBILITY(default)
- {
- _GLIBCXX_BEGIN_NAMESPACE_VERSION
- namespace ranges
- {
- // [range.access] customization point objects
- // [range.req] range and view concepts
- // [range.dangling] dangling iterator handling
- // Defined in <bits/ranges_base.h>
- // [view.interface] View interface
- // [range.subrange] Sub-ranges
- // Defined in <bits/ranges_util.h>
- // C++20 24.6 [range.factories] Range factories
- /// A view that contains no elements.
- template<typename _Tp> requires is_object_v<_Tp>
- class empty_view
- : public view_interface<empty_view<_Tp>>
- {
- public:
- static constexpr _Tp* begin() noexcept { return nullptr; }
- static constexpr _Tp* end() noexcept { return nullptr; }
- static constexpr _Tp* data() noexcept { return nullptr; }
- static constexpr size_t size() noexcept { return 0; }
- static constexpr bool empty() noexcept { return true; }
- };
- template<typename _Tp>
- inline constexpr bool enable_borrowed_range<empty_view<_Tp>> = true;
- namespace __detail
- {
- template<typename _Tp>
- concept __boxable = copy_constructible<_Tp> && is_object_v<_Tp>;
- template<__boxable _Tp>
- struct __box : std::optional<_Tp>
- {
- using std::optional<_Tp>::optional;
- constexpr
- __box()
- noexcept(is_nothrow_default_constructible_v<_Tp>)
- requires default_initializable<_Tp>
- : std::optional<_Tp>{std::in_place}
- { }
- __box(const __box&) = default;
- __box(__box&&) = default;
- using std::optional<_Tp>::operator=;
- // _GLIBCXX_RESOLVE_LIB_DEFECTS
- // 3477. Simplify constraints for semiregular-box
- // 3572. copyable-box should be fully constexpr
- constexpr __box&
- operator=(const __box& __that)
- noexcept(is_nothrow_copy_constructible_v<_Tp>)
- requires (!copyable<_Tp>)
- {
- if (this != std::__addressof(__that))
- {
- if ((bool)__that)
- this->emplace(*__that);
- else
- this->reset();
- }
- return *this;
- }
- constexpr __box&
- operator=(__box&& __that)
- noexcept(is_nothrow_move_constructible_v<_Tp>)
- requires (!movable<_Tp>)
- {
- if (this != std::__addressof(__that))
- {
- if ((bool)__that)
- this->emplace(std::move(*__that));
- else
- this->reset();
- }
- return *this;
- }
- };
- // For types which are already copyable, this specialization of the
- // copyable wrapper stores the object directly without going through
- // std::optional. It provides just the subset of the primary template's
- // API that we currently use.
- template<__boxable _Tp>
- requires copyable<_Tp> || (is_nothrow_move_constructible_v<_Tp>
- && is_nothrow_copy_constructible_v<_Tp>)
- struct __box<_Tp>
- {
- private:
- [[no_unique_address]] _Tp _M_value = _Tp();
- public:
- __box() requires default_initializable<_Tp> = default;
- constexpr explicit
- __box(const _Tp& __t)
- noexcept(is_nothrow_copy_constructible_v<_Tp>)
- : _M_value(__t)
- { }
- constexpr explicit
- __box(_Tp&& __t)
- noexcept(is_nothrow_move_constructible_v<_Tp>)
- : _M_value(std::move(__t))
- { }
- template<typename... _Args>
- requires constructible_from<_Tp, _Args...>
- constexpr explicit
- __box(in_place_t, _Args&&... __args)
- noexcept(is_nothrow_constructible_v<_Tp, _Args...>)
- : _M_value(std::forward<_Args>(__args)...)
- { }
- __box(const __box&) = default;
- __box(__box&&) = default;
- __box& operator=(const __box&) requires copyable<_Tp> = default;
- __box& operator=(__box&&) requires copyable<_Tp> = default;
- // When _Tp is nothrow_copy_constructible but not copy_assignable,
- // copy assignment is implemented via destroy-then-copy-construct.
- constexpr __box&
- operator=(const __box& __that) noexcept
- {
- static_assert(is_nothrow_copy_constructible_v<_Tp>);
- if (this != std::__addressof(__that))
- {
- _M_value.~_Tp();
- std::construct_at(std::__addressof(_M_value), *__that);
- }
- return *this;
- }
- // Likewise for move assignment.
- constexpr __box&
- operator=(__box&& __that) noexcept
- {
- static_assert(is_nothrow_move_constructible_v<_Tp>);
- if (this != std::__addressof(__that))
- {
- _M_value.~_Tp();
- std::construct_at(std::__addressof(_M_value), std::move(*__that));
- }
- return *this;
- }
- constexpr bool
- has_value() const noexcept
- { return true; };
- constexpr _Tp&
- operator*() noexcept
- { return _M_value; }
- constexpr const _Tp&
- operator*() const noexcept
- { return _M_value; }
- constexpr _Tp*
- operator->() noexcept
- { return std::__addressof(_M_value); }
- constexpr const _Tp*
- operator->() const noexcept
- { return std::__addressof(_M_value); }
- };
- } // namespace __detail
- /// A view that contains exactly one element.
- template<copy_constructible _Tp> requires is_object_v<_Tp>
- class single_view : public view_interface<single_view<_Tp>>
- {
- public:
- single_view() requires default_initializable<_Tp> = default;
- constexpr explicit
- single_view(const _Tp& __t)
- noexcept(is_nothrow_copy_constructible_v<_Tp>)
- : _M_value(__t)
- { }
- constexpr explicit
- single_view(_Tp&& __t)
- noexcept(is_nothrow_move_constructible_v<_Tp>)
- : _M_value(std::move(__t))
- { }
- // _GLIBCXX_RESOLVE_LIB_DEFECTS
- // 3428. single_view's in place constructor should be explicit
- template<typename... _Args>
- requires constructible_from<_Tp, _Args...>
- constexpr explicit
- single_view(in_place_t, _Args&&... __args)
- noexcept(is_nothrow_constructible_v<_Tp, _Args...>)
- : _M_value{in_place, std::forward<_Args>(__args)...}
- { }
- constexpr _Tp*
- begin() noexcept
- { return data(); }
- constexpr const _Tp*
- begin() const noexcept
- { return data(); }
- constexpr _Tp*
- end() noexcept
- { return data() + 1; }
- constexpr const _Tp*
- end() const noexcept
- { return data() + 1; }
- static constexpr size_t
- size() noexcept
- { return 1; }
- constexpr _Tp*
- data() noexcept
- { return _M_value.operator->(); }
- constexpr const _Tp*
- data() const noexcept
- { return _M_value.operator->(); }
- private:
- [[no_unique_address]] __detail::__box<_Tp> _M_value;
- };
- template<typename _Tp>
- single_view(_Tp) -> single_view<_Tp>;
- namespace __detail
- {
- template<typename _Wp>
- constexpr auto __to_signed_like(_Wp __w) noexcept
- {
- if constexpr (!integral<_Wp>)
- return iter_difference_t<_Wp>();
- else if constexpr (sizeof(iter_difference_t<_Wp>) > sizeof(_Wp))
- return iter_difference_t<_Wp>(__w);
- else if constexpr (sizeof(ptrdiff_t) > sizeof(_Wp))
- return ptrdiff_t(__w);
- else if constexpr (sizeof(long long) > sizeof(_Wp))
- return (long long)(__w);
- #ifdef __SIZEOF_INT128__
- else if constexpr (__SIZEOF_INT128__ > sizeof(_Wp))
- return __int128(__w);
- #endif
- else
- return __max_diff_type(__w);
- }
- template<typename _Wp>
- using __iota_diff_t = decltype(__to_signed_like(std::declval<_Wp>()));
- template<typename _It>
- concept __decrementable = incrementable<_It>
- && requires(_It __i)
- {
- { --__i } -> same_as<_It&>;
- { __i-- } -> same_as<_It>;
- };
- template<typename _It>
- concept __advanceable = __decrementable<_It> && totally_ordered<_It>
- && requires( _It __i, const _It __j, const __iota_diff_t<_It> __n)
- {
- { __i += __n } -> same_as<_It&>;
- { __i -= __n } -> same_as<_It&>;
- _It(__j + __n);
- _It(__n + __j);
- _It(__j - __n);
- { __j - __j } -> convertible_to<__iota_diff_t<_It>>;
- };
- template<typename _Winc>
- struct __iota_view_iter_cat
- { };
- template<incrementable _Winc>
- struct __iota_view_iter_cat<_Winc>
- { using iterator_category = input_iterator_tag; };
- } // namespace __detail
- template<weakly_incrementable _Winc,
- semiregular _Bound = unreachable_sentinel_t>
- requires std::__detail::__weakly_eq_cmp_with<_Winc, _Bound>
- && copyable<_Winc>
- class iota_view : public view_interface<iota_view<_Winc, _Bound>>
- {
- private:
- struct _Sentinel;
- struct _Iterator : __detail::__iota_view_iter_cat<_Winc>
- {
- private:
- static auto
- _S_iter_concept()
- {
- using namespace __detail;
- if constexpr (__advanceable<_Winc>)
- return random_access_iterator_tag{};
- else if constexpr (__decrementable<_Winc>)
- return bidirectional_iterator_tag{};
- else if constexpr (incrementable<_Winc>)
- return forward_iterator_tag{};
- else
- return input_iterator_tag{};
- }
- public:
- using iterator_concept = decltype(_S_iter_concept());
- // iterator_category defined in __iota_view_iter_cat
- using value_type = _Winc;
- using difference_type = __detail::__iota_diff_t<_Winc>;
- _Iterator() requires default_initializable<_Winc> = default;
- constexpr explicit
- _Iterator(_Winc __value)
- : _M_value(__value) { }
- constexpr _Winc
- operator*() const noexcept(is_nothrow_copy_constructible_v<_Winc>)
- { return _M_value; }
- constexpr _Iterator&
- operator++()
- {
- ++_M_value;
- return *this;
- }
- constexpr void
- operator++(int)
- { ++*this; }
- constexpr _Iterator
- operator++(int) requires incrementable<_Winc>
- {
- auto __tmp = *this;
- ++*this;
- return __tmp;
- }
- constexpr _Iterator&
- operator--() requires __detail::__decrementable<_Winc>
- {
- --_M_value;
- return *this;
- }
- constexpr _Iterator
- operator--(int) requires __detail::__decrementable<_Winc>
- {
- auto __tmp = *this;
- --*this;
- return __tmp;
- }
- constexpr _Iterator&
- operator+=(difference_type __n) requires __detail::__advanceable<_Winc>
- {
- using __detail::__is_integer_like;
- using __detail::__is_signed_integer_like;
- if constexpr (__is_integer_like<_Winc>
- && !__is_signed_integer_like<_Winc>)
- {
- if (__n >= difference_type(0))
- _M_value += static_cast<_Winc>(__n);
- else
- _M_value -= static_cast<_Winc>(-__n);
- }
- else
- _M_value += __n;
- return *this;
- }
- constexpr _Iterator&
- operator-=(difference_type __n) requires __detail::__advanceable<_Winc>
- {
- using __detail::__is_integer_like;
- using __detail::__is_signed_integer_like;
- if constexpr (__is_integer_like<_Winc>
- && !__is_signed_integer_like<_Winc>)
- {
- if (__n >= difference_type(0))
- _M_value -= static_cast<_Winc>(__n);
- else
- _M_value += static_cast<_Winc>(-__n);
- }
- else
- _M_value -= __n;
- return *this;
- }
- constexpr _Winc
- operator[](difference_type __n) const
- requires __detail::__advanceable<_Winc>
- { return _Winc(_M_value + __n); }
- friend constexpr bool
- operator==(const _Iterator& __x, const _Iterator& __y)
- requires equality_comparable<_Winc>
- { return __x._M_value == __y._M_value; }
- friend constexpr bool
- operator<(const _Iterator& __x, const _Iterator& __y)
- requires totally_ordered<_Winc>
- { return __x._M_value < __y._M_value; }
- friend constexpr bool
- operator>(const _Iterator& __x, const _Iterator& __y)
- requires totally_ordered<_Winc>
- { return __y < __x; }
- friend constexpr bool
- operator<=(const _Iterator& __x, const _Iterator& __y)
- requires totally_ordered<_Winc>
- { return !(__y < __x); }
- friend constexpr bool
- operator>=(const _Iterator& __x, const _Iterator& __y)
- requires totally_ordered<_Winc>
- { return !(__x < __y); }
- #ifdef __cpp_lib_three_way_comparison
- friend constexpr auto
- operator<=>(const _Iterator& __x, const _Iterator& __y)
- requires totally_ordered<_Winc> && three_way_comparable<_Winc>
- { return __x._M_value <=> __y._M_value; }
- #endif
- friend constexpr _Iterator
- operator+(_Iterator __i, difference_type __n)
- requires __detail::__advanceable<_Winc>
- {
- __i += __n;
- return __i;
- }
- friend constexpr _Iterator
- operator+(difference_type __n, _Iterator __i)
- requires __detail::__advanceable<_Winc>
- { return __i += __n; }
- friend constexpr _Iterator
- operator-(_Iterator __i, difference_type __n)
- requires __detail::__advanceable<_Winc>
- {
- __i -= __n;
- return __i;
- }
- friend constexpr difference_type
- operator-(const _Iterator& __x, const _Iterator& __y)
- requires __detail::__advanceable<_Winc>
- {
- using __detail::__is_integer_like;
- using __detail::__is_signed_integer_like;
- using _Dt = difference_type;
- if constexpr (__is_integer_like<_Winc>)
- {
- if constexpr (__is_signed_integer_like<_Winc>)
- return _Dt(_Dt(__x._M_value) - _Dt(__y._M_value));
- else
- return (__y._M_value > __x._M_value)
- ? _Dt(-_Dt(__y._M_value - __x._M_value))
- : _Dt(__x._M_value - __y._M_value);
- }
- else
- return __x._M_value - __y._M_value;
- }
- private:
- _Winc _M_value = _Winc();
- friend iota_view;
- friend _Sentinel;
- };
- struct _Sentinel
- {
- private:
- constexpr bool
- _M_equal(const _Iterator& __x) const
- { return __x._M_value == _M_bound; }
- constexpr auto
- _M_distance_from(const _Iterator& __x) const
- { return _M_bound - __x._M_value; }
- _Bound _M_bound = _Bound();
- public:
- _Sentinel() = default;
- constexpr explicit
- _Sentinel(_Bound __bound)
- : _M_bound(__bound) { }
- friend constexpr bool
- operator==(const _Iterator& __x, const _Sentinel& __y)
- { return __y._M_equal(__x); }
- friend constexpr iter_difference_t<_Winc>
- operator-(const _Iterator& __x, const _Sentinel& __y)
- requires sized_sentinel_for<_Bound, _Winc>
- { return -__y._M_distance_from(__x); }
- friend constexpr iter_difference_t<_Winc>
- operator-(const _Sentinel& __x, const _Iterator& __y)
- requires sized_sentinel_for<_Bound, _Winc>
- { return __x._M_distance_from(__y); }
- friend iota_view;
- };
- _Winc _M_value = _Winc();
- [[no_unique_address]] _Bound _M_bound = _Bound();
- public:
- iota_view() requires default_initializable<_Winc> = default;
- constexpr explicit
- iota_view(_Winc __value)
- : _M_value(__value)
- { }
- constexpr
- iota_view(type_identity_t<_Winc> __value,
- type_identity_t<_Bound> __bound)
- : _M_value(__value), _M_bound(__bound)
- {
- if constexpr (totally_ordered_with<_Winc, _Bound>)
- __glibcxx_assert( bool(__value <= __bound) );
- }
- constexpr
- iota_view(_Iterator __first, _Iterator __last)
- requires same_as<_Winc, _Bound>
- : iota_view(__first._M_value, __last._M_value)
- { }
- constexpr
- iota_view(_Iterator __first, unreachable_sentinel_t __last)
- requires same_as<_Bound, unreachable_sentinel_t>
- : iota_view(__first._M_value, __last)
- { }
- constexpr
- iota_view(_Iterator __first, _Sentinel __last)
- requires (!same_as<_Winc, _Bound>) && (!same_as<_Bound, unreachable_sentinel_t>)
- : iota_view(__first._M_value, __last._M_bound)
- { }
- constexpr _Iterator
- begin() const { return _Iterator{_M_value}; }
- constexpr auto
- end() const
- {
- if constexpr (same_as<_Bound, unreachable_sentinel_t>)
- return unreachable_sentinel;
- else
- return _Sentinel{_M_bound};
- }
- constexpr _Iterator
- end() const requires same_as<_Winc, _Bound>
- { return _Iterator{_M_bound}; }
- constexpr auto
- size() const
- requires (same_as<_Winc, _Bound> && __detail::__advanceable<_Winc>)
- || (integral<_Winc> && integral<_Bound>)
- || sized_sentinel_for<_Bound, _Winc>
- {
- using __detail::__is_integer_like;
- using __detail::__to_unsigned_like;
- if constexpr (integral<_Winc> && integral<_Bound>)
- {
- using _Up = make_unsigned_t<decltype(_M_bound - _M_value)>;
- return _Up(_M_bound) - _Up(_M_value);
- }
- else if constexpr (__is_integer_like<_Winc>)
- return __to_unsigned_like(_M_bound) - __to_unsigned_like(_M_value);
- else
- return __to_unsigned_like(_M_bound - _M_value);
- }
- };
- template<typename _Winc, typename _Bound>
- requires (!__detail::__is_integer_like<_Winc>
- || !__detail::__is_integer_like<_Bound>
- || (__detail::__is_signed_integer_like<_Winc>
- == __detail::__is_signed_integer_like<_Bound>))
- iota_view(_Winc, _Bound) -> iota_view<_Winc, _Bound>;
- template<typename _Winc, typename _Bound>
- inline constexpr bool
- enable_borrowed_range<iota_view<_Winc, _Bound>> = true;
- namespace views
- {
- template<typename _Tp>
- inline constexpr empty_view<_Tp> empty{};
- struct _Single
- {
- template<typename _Tp>
- [[nodiscard]]
- constexpr auto
- operator()(_Tp&& __e) const
- noexcept(noexcept(single_view<decay_t<_Tp>>(std::forward<_Tp>(__e))))
- { return single_view<decay_t<_Tp>>(std::forward<_Tp>(__e)); }
- };
- inline constexpr _Single single{};
- struct _Iota
- {
- template<typename _Tp>
- [[nodiscard]]
- constexpr auto
- operator()(_Tp&& __e) const
- { return iota_view(std::forward<_Tp>(__e)); }
- template<typename _Tp, typename _Up>
- [[nodiscard]]
- constexpr auto
- operator()(_Tp&& __e, _Up&& __f) const
- { return iota_view(std::forward<_Tp>(__e), std::forward<_Up>(__f)); }
- };
- inline constexpr _Iota iota{};
- } // namespace views
- namespace __detail
- {
- template<typename _Val, typename _CharT, typename _Traits>
- concept __stream_extractable
- = requires(basic_istream<_CharT, _Traits>& is, _Val& t) { is >> t; };
- } // namespace __detail
- template<movable _Val, typename _CharT,
- typename _Traits = char_traits<_CharT>>
- requires default_initializable<_Val>
- && __detail::__stream_extractable<_Val, _CharT, _Traits>
- class basic_istream_view
- : public view_interface<basic_istream_view<_Val, _CharT, _Traits>>
- {
- public:
- constexpr explicit
- basic_istream_view(basic_istream<_CharT, _Traits>& __stream)
- : _M_stream(std::__addressof(__stream))
- { }
- constexpr auto
- begin()
- {
- *_M_stream >> _M_object;
- return _Iterator{this};
- }
- constexpr default_sentinel_t
- end() const noexcept
- { return default_sentinel; }
- private:
- basic_istream<_CharT, _Traits>* _M_stream;
- _Val _M_object = _Val();
- struct _Iterator
- {
- public:
- using iterator_concept = input_iterator_tag;
- using difference_type = ptrdiff_t;
- using value_type = _Val;
- constexpr explicit
- _Iterator(basic_istream_view* __parent) noexcept
- : _M_parent(__parent)
- { }
- _Iterator(const _Iterator&) = delete;
- _Iterator(_Iterator&&) = default;
- _Iterator& operator=(const _Iterator&) = delete;
- _Iterator& operator=(_Iterator&&) = default;
- _Iterator&
- operator++()
- {
- *_M_parent->_M_stream >> _M_parent->_M_object;
- return *this;
- }
- void
- operator++(int)
- { ++*this; }
- _Val&
- operator*() const
- { return _M_parent->_M_object; }
- friend bool
- operator==(const _Iterator& __x, default_sentinel_t)
- { return __x._M_at_end(); }
- private:
- basic_istream_view* _M_parent;
- bool
- _M_at_end() const
- { return !*_M_parent->_M_stream; }
- };
- friend _Iterator;
- };
- template<typename _Val>
- using istream_view = basic_istream_view<_Val, char>;
- template<typename _Val>
- using wistream_view = basic_istream_view<_Val, wchar_t>;
- namespace views
- {
- template<typename _Tp>
- struct _Istream
- {
- template<typename _CharT, typename _Traits>
- [[nodiscard]]
- constexpr auto
- operator()(basic_istream<_CharT, _Traits>& __e) const
- { return basic_istream_view<_Tp, _CharT, _Traits>(__e); }
- };
- template<typename _Tp>
- inline constexpr _Istream<_Tp> istream;
- }
- // C++20 24.7 [range.adaptors] Range adaptors
- namespace __detail
- {
- struct _Empty { };
- // Alias for a type that is conditionally present
- // (and is an empty type otherwise).
- // Data members using this alias should use [[no_unique_address]] so that
- // they take no space when not needed.
- template<bool _Present, typename _Tp>
- using __maybe_present_t = __conditional_t<_Present, _Tp, _Empty>;
- // Alias for a type that is conditionally const.
- template<bool _Const, typename _Tp>
- using __maybe_const_t = __conditional_t<_Const, const _Tp, _Tp>;
- } // namespace __detail
- namespace views::__adaptor
- {
- // True if the range adaptor _Adaptor can be applied with _Args.
- template<typename _Adaptor, typename... _Args>
- concept __adaptor_invocable
- = requires { std::declval<_Adaptor>()(declval<_Args>()...); };
- // True if the range adaptor non-closure _Adaptor can be partially applied
- // with _Args.
- template<typename _Adaptor, typename... _Args>
- concept __adaptor_partial_app_viable = (_Adaptor::_S_arity > 1)
- && (sizeof...(_Args) == _Adaptor::_S_arity - 1)
- && (constructible_from<decay_t<_Args>, _Args> && ...);
- template<typename _Adaptor, typename... _Args>
- struct _Partial;
- template<typename _Lhs, typename _Rhs>
- struct _Pipe;
- // The base class of every range adaptor closure.
- //
- // The derived class should define the optional static data member
- // _S_has_simple_call_op to true if the behavior of this adaptor is
- // independent of the constness/value category of the adaptor object.
- struct _RangeAdaptorClosure
- {
- // range | adaptor is equivalent to adaptor(range).
- template<typename _Self, typename _Range>
- requires derived_from<remove_cvref_t<_Self>, _RangeAdaptorClosure>
- && __adaptor_invocable<_Self, _Range>
- friend constexpr auto
- operator|(_Range&& __r, _Self&& __self)
- { return std::forward<_Self>(__self)(std::forward<_Range>(__r)); }
- // Compose the adaptors __lhs and __rhs into a pipeline, returning
- // another range adaptor closure object.
- template<typename _Lhs, typename _Rhs>
- requires derived_from<_Lhs, _RangeAdaptorClosure>
- && derived_from<_Rhs, _RangeAdaptorClosure>
- friend constexpr auto
- operator|(_Lhs __lhs, _Rhs __rhs)
- { return _Pipe<_Lhs, _Rhs>{std::move(__lhs), std::move(__rhs)}; }
- };
- // The base class of every range adaptor non-closure.
- //
- // The static data member _Derived::_S_arity must contain the total number of
- // arguments that the adaptor takes, and the class _Derived must introduce
- // _RangeAdaptor::operator() into the class scope via a using-declaration.
- //
- // The optional static data member _Derived::_S_has_simple_extra_args should
- // be defined to true if the behavior of this adaptor is independent of the
- // constness/value category of the extra arguments. This data member could
- // also be defined as a variable template parameterized by the types of the
- // extra arguments.
- template<typename _Derived>
- struct _RangeAdaptor
- {
- // Partially apply the arguments __args to the range adaptor _Derived,
- // returning a range adaptor closure object.
- template<typename... _Args>
- requires __adaptor_partial_app_viable<_Derived, _Args...>
- constexpr auto
- operator()(_Args&&... __args) const
- {
- return _Partial<_Derived, decay_t<_Args>...>{std::forward<_Args>(__args)...};
- }
- };
- // True if the range adaptor closure _Adaptor has a simple operator(), i.e.
- // one that's not overloaded according to constness or value category of the
- // _Adaptor object.
- template<typename _Adaptor>
- concept __closure_has_simple_call_op = _Adaptor::_S_has_simple_call_op;
- // True if the behavior of the range adaptor non-closure _Adaptor is
- // independent of the value category of its extra arguments _Args.
- template<typename _Adaptor, typename... _Args>
- concept __adaptor_has_simple_extra_args = _Adaptor::_S_has_simple_extra_args
- || _Adaptor::template _S_has_simple_extra_args<_Args...>;
- // A range adaptor closure that represents partial application of
- // the range adaptor _Adaptor with arguments _Args.
- template<typename _Adaptor, typename... _Args>
- struct _Partial : _RangeAdaptorClosure
- {
- tuple<_Args...> _M_args;
- constexpr
- _Partial(_Args... __args)
- : _M_args(std::move(__args)...)
- { }
- // Invoke _Adaptor with arguments __r, _M_args... according to the
- // value category of this _Partial object.
- template<typename _Range>
- requires __adaptor_invocable<_Adaptor, _Range, const _Args&...>
- constexpr auto
- operator()(_Range&& __r) const &
- {
- auto __forwarder = [&__r] (const auto&... __args) {
- return _Adaptor{}(std::forward<_Range>(__r), __args...);
- };
- return std::apply(__forwarder, _M_args);
- }
- template<typename _Range>
- requires __adaptor_invocable<_Adaptor, _Range, _Args...>
- constexpr auto
- operator()(_Range&& __r) &&
- {
- auto __forwarder = [&__r] (auto&... __args) {
- return _Adaptor{}(std::forward<_Range>(__r), std::move(__args)...);
- };
- return std::apply(__forwarder, _M_args);
- }
- template<typename _Range>
- constexpr auto
- operator()(_Range&& __r) const && = delete;
- };
- // A lightweight specialization of the above primary template for
- // the common case where _Adaptor accepts a single extra argument.
- template<typename _Adaptor, typename _Arg>
- struct _Partial<_Adaptor, _Arg> : _RangeAdaptorClosure
- {
- _Arg _M_arg;
- constexpr
- _Partial(_Arg __arg)
- : _M_arg(std::move(__arg))
- { }
- template<typename _Range>
- requires __adaptor_invocable<_Adaptor, _Range, const _Arg&>
- constexpr auto
- operator()(_Range&& __r) const &
- { return _Adaptor{}(std::forward<_Range>(__r), _M_arg); }
- template<typename _Range>
- requires __adaptor_invocable<_Adaptor, _Range, _Arg>
- constexpr auto
- operator()(_Range&& __r) &&
- { return _Adaptor{}(std::forward<_Range>(__r), std::move(_M_arg)); }
- template<typename _Range>
- constexpr auto
- operator()(_Range&& __r) const && = delete;
- };
- // Partial specialization of the primary template for the case where the extra
- // arguments of the adaptor can always be safely and efficiently forwarded by
- // const reference. This lets us get away with a single operator() overload,
- // which makes overload resolution failure diagnostics more concise.
- template<typename _Adaptor, typename... _Args>
- requires __adaptor_has_simple_extra_args<_Adaptor, _Args...>
- && (is_trivially_copyable_v<_Args> && ...)
- struct _Partial<_Adaptor, _Args...> : _RangeAdaptorClosure
- {
- tuple<_Args...> _M_args;
- constexpr
- _Partial(_Args... __args)
- : _M_args(std::move(__args)...)
- { }
- // Invoke _Adaptor with arguments __r, const _M_args&... regardless
- // of the value category of this _Partial object.
- template<typename _Range>
- requires __adaptor_invocable<_Adaptor, _Range, const _Args&...>
- constexpr auto
- operator()(_Range&& __r) const
- {
- auto __forwarder = [&__r] (const auto&... __args) {
- return _Adaptor{}(std::forward<_Range>(__r), __args...);
- };
- return std::apply(__forwarder, _M_args);
- }
- static constexpr bool _S_has_simple_call_op = true;
- };
- // A lightweight specialization of the above template for the common case
- // where _Adaptor accepts a single extra argument.
- template<typename _Adaptor, typename _Arg>
- requires __adaptor_has_simple_extra_args<_Adaptor, _Arg>
- && is_trivially_copyable_v<_Arg>
- struct _Partial<_Adaptor, _Arg> : _RangeAdaptorClosure
- {
- _Arg _M_arg;
- constexpr
- _Partial(_Arg __arg)
- : _M_arg(std::move(__arg))
- { }
- template<typename _Range>
- requires __adaptor_invocable<_Adaptor, _Range, const _Arg&>
- constexpr auto
- operator()(_Range&& __r) const
- { return _Adaptor{}(std::forward<_Range>(__r), _M_arg); }
- static constexpr bool _S_has_simple_call_op = true;
- };
- template<typename _Lhs, typename _Rhs, typename _Range>
- concept __pipe_invocable
- = requires { std::declval<_Rhs>()(std::declval<_Lhs>()(std::declval<_Range>())); };
- // A range adaptor closure that represents composition of the range
- // adaptor closures _Lhs and _Rhs.
- template<typename _Lhs, typename _Rhs>
- struct _Pipe : _RangeAdaptorClosure
- {
- [[no_unique_address]] _Lhs _M_lhs;
- [[no_unique_address]] _Rhs _M_rhs;
- constexpr
- _Pipe(_Lhs __lhs, _Rhs __rhs)
- : _M_lhs(std::move(__lhs)), _M_rhs(std::move(__rhs))
- { }
- // Invoke _M_rhs(_M_lhs(__r)) according to the value category of this
- // range adaptor closure object.
- template<typename _Range>
- requires __pipe_invocable<const _Lhs&, const _Rhs&, _Range>
- constexpr auto
- operator()(_Range&& __r) const &
- { return _M_rhs(_M_lhs(std::forward<_Range>(__r))); }
- template<typename _Range>
- requires __pipe_invocable<_Lhs, _Rhs, _Range>
- constexpr auto
- operator()(_Range&& __r) &&
- { return std::move(_M_rhs)(std::move(_M_lhs)(std::forward<_Range>(__r))); }
- template<typename _Range>
- constexpr auto
- operator()(_Range&& __r) const && = delete;
- };
- // A partial specialization of the above primary template for the case where
- // both adaptor operands have a simple operator(). This in turn lets us
- // implement composition using a single simple operator(), which makes
- // overload resolution failure diagnostics more concise.
- template<typename _Lhs, typename _Rhs>
- requires __closure_has_simple_call_op<_Lhs>
- && __closure_has_simple_call_op<_Rhs>
- struct _Pipe<_Lhs, _Rhs> : _RangeAdaptorClosure
- {
- [[no_unique_address]] _Lhs _M_lhs;
- [[no_unique_address]] _Rhs _M_rhs;
- constexpr
- _Pipe(_Lhs __lhs, _Rhs __rhs)
- : _M_lhs(std::move(__lhs)), _M_rhs(std::move(__rhs))
- { }
- template<typename _Range>
- requires __pipe_invocable<const _Lhs&, const _Rhs&, _Range>
- constexpr auto
- operator()(_Range&& __r) const
- { return _M_rhs(_M_lhs(std::forward<_Range>(__r))); }
- static constexpr bool _S_has_simple_call_op = true;
- };
- } // namespace views::__adaptor
- template<range _Range> requires is_object_v<_Range>
- class ref_view : public view_interface<ref_view<_Range>>
- {
- private:
- _Range* _M_r;
- static void _S_fun(_Range&); // not defined
- static void _S_fun(_Range&&) = delete;
- public:
- template<__detail::__different_from<ref_view> _Tp>
- requires convertible_to<_Tp, _Range&>
- && requires { _S_fun(declval<_Tp>()); }
- constexpr
- ref_view(_Tp&& __t)
- noexcept(noexcept(static_cast<_Range&>(std::declval<_Tp>())))
- : _M_r(std::__addressof(static_cast<_Range&>(std::forward<_Tp>(__t))))
- { }
- constexpr _Range&
- base() const
- { return *_M_r; }
- constexpr iterator_t<_Range>
- begin() const
- { return ranges::begin(*_M_r); }
- constexpr sentinel_t<_Range>
- end() const
- { return ranges::end(*_M_r); }
- constexpr bool
- empty() const requires requires { ranges::empty(*_M_r); }
- { return ranges::empty(*_M_r); }
- constexpr auto
- size() const requires sized_range<_Range>
- { return ranges::size(*_M_r); }
- constexpr auto
- data() const requires contiguous_range<_Range>
- { return ranges::data(*_M_r); }
- };
- template<typename _Range>
- ref_view(_Range&) -> ref_view<_Range>;
- template<typename _Tp>
- inline constexpr bool enable_borrowed_range<ref_view<_Tp>> = true;
- template<range _Range>
- requires movable<_Range>
- && (!__detail::__is_initializer_list<remove_cv_t<_Range>>)
- class owning_view : public view_interface<owning_view<_Range>>
- {
- private:
- _Range _M_r = _Range();
- public:
- owning_view() requires default_initializable<_Range> = default;
- constexpr
- owning_view(_Range&& __t)
- noexcept(is_nothrow_move_constructible_v<_Range>)
- : _M_r(std::move(__t))
- { }
- owning_view(owning_view&&) = default;
- owning_view& operator=(owning_view&&) = default;
- constexpr _Range&
- base() & noexcept
- { return _M_r; }
- constexpr const _Range&
- base() const& noexcept
- { return _M_r; }
- constexpr _Range&&
- base() && noexcept
- { return std::move(_M_r); }
- constexpr const _Range&&
- base() const&& noexcept
- { return std::move(_M_r); }
- constexpr iterator_t<_Range>
- begin()
- { return ranges::begin(_M_r); }
- constexpr sentinel_t<_Range>
- end()
- { return ranges::end(_M_r); }
- constexpr auto
- begin() const requires range<const _Range>
- { return ranges::begin(_M_r); }
- constexpr auto
- end() const requires range<const _Range>
- { return ranges::end(_M_r); }
- constexpr bool
- empty() requires requires { ranges::empty(_M_r); }
- { return ranges::empty(_M_r); }
- constexpr bool
- empty() const requires requires { ranges::empty(_M_r); }
- { return ranges::empty(_M_r); }
- constexpr auto
- size() requires sized_range<_Range>
- { return ranges::size(_M_r); }
- constexpr auto
- size() const requires sized_range<const _Range>
- { return ranges::size(_M_r); }
- constexpr auto
- data() requires contiguous_range<_Range>
- { return ranges::data(_M_r); }
- constexpr auto
- data() const requires contiguous_range<const _Range>
- { return ranges::data(_M_r); }
- };
- template<typename _Tp>
- inline constexpr bool enable_borrowed_range<owning_view<_Tp>>
- = enable_borrowed_range<_Tp>;
- namespace views
- {
- namespace __detail
- {
- template<typename _Range>
- concept __can_ref_view = requires { ref_view{std::declval<_Range>()}; };
- template<typename _Range>
- concept __can_owning_view = requires { owning_view{std::declval<_Range>()}; };
- } // namespace __detail
- struct _All : __adaptor::_RangeAdaptorClosure
- {
- template<typename _Range>
- static constexpr bool
- _S_noexcept()
- {
- if constexpr (view<decay_t<_Range>>)
- return is_nothrow_constructible_v<decay_t<_Range>, _Range>;
- else if constexpr (__detail::__can_ref_view<_Range>)
- return true;
- else
- return noexcept(owning_view{std::declval<_Range>()});
- }
- template<viewable_range _Range>
- requires view<decay_t<_Range>>
- || __detail::__can_ref_view<_Range>
- || __detail::__can_owning_view<_Range>
- constexpr auto
- operator() [[nodiscard]] (_Range&& __r) const
- noexcept(_S_noexcept<_Range>())
- {
- if constexpr (view<decay_t<_Range>>)
- return std::forward<_Range>(__r);
- else if constexpr (__detail::__can_ref_view<_Range>)
- return ref_view{std::forward<_Range>(__r)};
- else
- return owning_view{std::forward<_Range>(__r)};
- }
- static constexpr bool _S_has_simple_call_op = true;
- };
- inline constexpr _All all;
- template<viewable_range _Range>
- using all_t = decltype(all(std::declval<_Range>()));
- } // namespace views
- namespace __detail
- {
- template<typename _Tp>
- struct __non_propagating_cache
- {
- // When _Tp is not an object type (e.g. is a reference type), we make
- // __non_propagating_cache<_Tp> empty rather than ill-formed so that
- // users can easily conditionally declare data members with this type
- // (such as join_view::_M_inner).
- };
- template<typename _Tp>
- requires is_object_v<_Tp>
- struct __non_propagating_cache<_Tp>
- : protected _Optional_base<_Tp>
- {
- __non_propagating_cache() = default;
- constexpr
- __non_propagating_cache(const __non_propagating_cache&) noexcept
- { }
- constexpr
- __non_propagating_cache(__non_propagating_cache&& __other) noexcept
- { __other._M_reset(); }
- constexpr __non_propagating_cache&
- operator=(const __non_propagating_cache& __other) noexcept
- {
- if (std::__addressof(__other) != this)
- this->_M_reset();
- return *this;
- }
- constexpr __non_propagating_cache&
- operator=(__non_propagating_cache&& __other) noexcept
- {
- this->_M_reset();
- __other._M_reset();
- return *this;
- }
- constexpr __non_propagating_cache&
- operator=(_Tp __val)
- {
- this->_M_reset();
- this->_M_payload._M_construct(std::move(__val));
- return *this;
- }
- constexpr explicit
- operator bool() const noexcept
- { return this->_M_is_engaged(); }
- constexpr _Tp&
- operator*() noexcept
- { return this->_M_get(); }
- constexpr const _Tp&
- operator*() const noexcept
- { return this->_M_get(); }
- template<typename _Iter>
- constexpr _Tp&
- _M_emplace_deref(const _Iter& __i)
- {
- this->_M_reset();
- auto __f = [] (auto& __x) { return *__x; };
- this->_M_payload._M_apply(_Optional_func{__f}, __i);
- return this->_M_get();
- }
- };
- template<range _Range>
- struct _CachedPosition
- {
- constexpr bool
- _M_has_value() const
- { return false; }
- constexpr iterator_t<_Range>
- _M_get(const _Range&) const
- {
- __glibcxx_assert(false);
- __builtin_unreachable();
- }
- constexpr void
- _M_set(const _Range&, const iterator_t<_Range>&) const
- { }
- };
- template<forward_range _Range>
- struct _CachedPosition<_Range>
- : protected __non_propagating_cache<iterator_t<_Range>>
- {
- constexpr bool
- _M_has_value() const
- { return this->_M_is_engaged(); }
- constexpr iterator_t<_Range>
- _M_get(const _Range&) const
- {
- __glibcxx_assert(_M_has_value());
- return **this;
- }
- constexpr void
- _M_set(const _Range&, const iterator_t<_Range>& __it)
- {
- __glibcxx_assert(!_M_has_value());
- std::construct_at(std::__addressof(this->_M_payload._M_payload),
- in_place, __it);
- this->_M_payload._M_engaged = true;
- }
- };
- template<random_access_range _Range>
- requires (sizeof(range_difference_t<_Range>)
- <= sizeof(iterator_t<_Range>))
- struct _CachedPosition<_Range>
- {
- private:
- range_difference_t<_Range> _M_offset = -1;
- public:
- _CachedPosition() = default;
- constexpr
- _CachedPosition(const _CachedPosition&) = default;
- constexpr
- _CachedPosition(_CachedPosition&& __other) noexcept
- { *this = std::move(__other); }
- constexpr _CachedPosition&
- operator=(const _CachedPosition&) = default;
- constexpr _CachedPosition&
- operator=(_CachedPosition&& __other) noexcept
- {
- // Propagate the cached offset, but invalidate the source.
- _M_offset = __other._M_offset;
- __other._M_offset = -1;
- return *this;
- }
- constexpr bool
- _M_has_value() const
- { return _M_offset >= 0; }
- constexpr iterator_t<_Range>
- _M_get(_Range& __r) const
- {
- __glibcxx_assert(_M_has_value());
- return ranges::begin(__r) + _M_offset;
- }
- constexpr void
- _M_set(_Range& __r, const iterator_t<_Range>& __it)
- {
- __glibcxx_assert(!_M_has_value());
- _M_offset = __it - ranges::begin(__r);
- }
- };
- } // namespace __detail
- namespace __detail
- {
- template<typename _Base>
- struct __filter_view_iter_cat
- { };
- template<forward_range _Base>
- struct __filter_view_iter_cat<_Base>
- {
- private:
- static auto
- _S_iter_cat()
- {
- using _Cat = typename iterator_traits<iterator_t<_Base>>::iterator_category;
- if constexpr (derived_from<_Cat, bidirectional_iterator_tag>)
- return bidirectional_iterator_tag{};
- else if constexpr (derived_from<_Cat, forward_iterator_tag>)
- return forward_iterator_tag{};
- else
- return _Cat{};
- }
- public:
- using iterator_category = decltype(_S_iter_cat());
- };
- } // namespace __detail
- template<input_range _Vp,
- indirect_unary_predicate<iterator_t<_Vp>> _Pred>
- requires view<_Vp> && is_object_v<_Pred>
- class filter_view : public view_interface<filter_view<_Vp, _Pred>>
- {
- private:
- struct _Sentinel;
- struct _Iterator : __detail::__filter_view_iter_cat<_Vp>
- {
- private:
- static constexpr auto
- _S_iter_concept()
- {
- if constexpr (bidirectional_range<_Vp>)
- return bidirectional_iterator_tag{};
- else if constexpr (forward_range<_Vp>)
- return forward_iterator_tag{};
- else
- return input_iterator_tag{};
- }
- friend filter_view;
- using _Vp_iter = iterator_t<_Vp>;
- _Vp_iter _M_current = _Vp_iter();
- filter_view* _M_parent = nullptr;
- public:
- using iterator_concept = decltype(_S_iter_concept());
- // iterator_category defined in __filter_view_iter_cat
- using value_type = range_value_t<_Vp>;
- using difference_type = range_difference_t<_Vp>;
- _Iterator() requires default_initializable<_Vp_iter> = default;
- constexpr
- _Iterator(filter_view* __parent, _Vp_iter __current)
- : _M_current(std::move(__current)),
- _M_parent(__parent)
- { }
- constexpr const _Vp_iter&
- base() const & noexcept
- { return _M_current; }
- constexpr _Vp_iter
- base() &&
- { return std::move(_M_current); }
- constexpr range_reference_t<_Vp>
- operator*() const
- { return *_M_current; }
- constexpr _Vp_iter
- operator->() const
- requires __detail::__has_arrow<_Vp_iter>
- && copyable<_Vp_iter>
- { return _M_current; }
- constexpr _Iterator&
- operator++()
- {
- _M_current = ranges::find_if(std::move(++_M_current),
- ranges::end(_M_parent->_M_base),
- std::ref(*_M_parent->_M_pred));
- return *this;
- }
- constexpr void
- operator++(int)
- { ++*this; }
- constexpr _Iterator
- operator++(int) requires forward_range<_Vp>
- {
- auto __tmp = *this;
- ++*this;
- return __tmp;
- }
- constexpr _Iterator&
- operator--() requires bidirectional_range<_Vp>
- {
- do
- --_M_current;
- while (!std::__invoke(*_M_parent->_M_pred, *_M_current));
- return *this;
- }
- constexpr _Iterator
- operator--(int) requires bidirectional_range<_Vp>
- {
- auto __tmp = *this;
- --*this;
- return __tmp;
- }
- friend constexpr bool
- operator==(const _Iterator& __x, const _Iterator& __y)
- requires equality_comparable<_Vp_iter>
- { return __x._M_current == __y._M_current; }
- friend constexpr range_rvalue_reference_t<_Vp>
- iter_move(const _Iterator& __i)
- noexcept(noexcept(ranges::iter_move(__i._M_current)))
- { return ranges::iter_move(__i._M_current); }
- friend constexpr void
- iter_swap(const _Iterator& __x, const _Iterator& __y)
- noexcept(noexcept(ranges::iter_swap(__x._M_current, __y._M_current)))
- requires indirectly_swappable<_Vp_iter>
- { ranges::iter_swap(__x._M_current, __y._M_current); }
- };
- struct _Sentinel
- {
- private:
- sentinel_t<_Vp> _M_end = sentinel_t<_Vp>();
- constexpr bool
- __equal(const _Iterator& __i) const
- { return __i._M_current == _M_end; }
- public:
- _Sentinel() = default;
- constexpr explicit
- _Sentinel(filter_view* __parent)
- : _M_end(ranges::end(__parent->_M_base))
- { }
- constexpr sentinel_t<_Vp>
- base() const
- { return _M_end; }
- friend constexpr bool
- operator==(const _Iterator& __x, const _Sentinel& __y)
- { return __y.__equal(__x); }
- };
- _Vp _M_base = _Vp();
- [[no_unique_address]] __detail::__box<_Pred> _M_pred;
- [[no_unique_address]] __detail::_CachedPosition<_Vp> _M_cached_begin;
- public:
- filter_view() requires (default_initializable<_Vp>
- && default_initializable<_Pred>)
- = default;
- constexpr
- filter_view(_Vp __base, _Pred __pred)
- : _M_base(std::move(__base)), _M_pred(std::move(__pred))
- { }
- constexpr _Vp
- base() const& requires copy_constructible<_Vp>
- { return _M_base; }
- constexpr _Vp
- base() &&
- { return std::move(_M_base); }
- constexpr const _Pred&
- pred() const
- { return *_M_pred; }
- constexpr _Iterator
- begin()
- {
- if (_M_cached_begin._M_has_value())
- return {this, _M_cached_begin._M_get(_M_base)};
- __glibcxx_assert(_M_pred.has_value());
- auto __it = ranges::find_if(ranges::begin(_M_base),
- ranges::end(_M_base),
- std::ref(*_M_pred));
- _M_cached_begin._M_set(_M_base, __it);
- return {this, std::move(__it)};
- }
- constexpr auto
- end()
- {
- if constexpr (common_range<_Vp>)
- return _Iterator{this, ranges::end(_M_base)};
- else
- return _Sentinel{this};
- }
- };
- template<typename _Range, typename _Pred>
- filter_view(_Range&&, _Pred) -> filter_view<views::all_t<_Range>, _Pred>;
- namespace views
- {
- namespace __detail
- {
- template<typename _Range, typename _Pred>
- concept __can_filter_view
- = requires { filter_view(std::declval<_Range>(), std::declval<_Pred>()); };
- } // namespace __detail
- struct _Filter : __adaptor::_RangeAdaptor<_Filter>
- {
- template<viewable_range _Range, typename _Pred>
- requires __detail::__can_filter_view<_Range, _Pred>
- constexpr auto
- operator() [[nodiscard]] (_Range&& __r, _Pred&& __p) const
- {
- return filter_view(std::forward<_Range>(__r), std::forward<_Pred>(__p));
- }
- using _RangeAdaptor<_Filter>::operator();
- static constexpr int _S_arity = 2;
- static constexpr bool _S_has_simple_extra_args = true;
- };
- inline constexpr _Filter filter;
- } // namespace views
- template<input_range _Vp, copy_constructible _Fp>
- requires view<_Vp> && is_object_v<_Fp>
- && regular_invocable<_Fp&, range_reference_t<_Vp>>
- && std::__detail::__can_reference<invoke_result_t<_Fp&,
- range_reference_t<_Vp>>>
- class transform_view : public view_interface<transform_view<_Vp, _Fp>>
- {
- private:
- template<bool _Const>
- using _Base = __detail::__maybe_const_t<_Const, _Vp>;
- template<bool _Const>
- struct __iter_cat
- { };
- template<bool _Const>
- requires forward_range<_Base<_Const>>
- struct __iter_cat<_Const>
- {
- private:
- static auto
- _S_iter_cat()
- {
- using _Base = transform_view::_Base<_Const>;
- using _Res = invoke_result_t<_Fp&, range_reference_t<_Base>>;
- if constexpr (is_lvalue_reference_v<_Res>)
- {
- using _Cat
- = typename iterator_traits<iterator_t<_Base>>::iterator_category;
- if constexpr (derived_from<_Cat, contiguous_iterator_tag>)
- return random_access_iterator_tag{};
- else
- return _Cat{};
- }
- else
- return input_iterator_tag{};
- }
- public:
- using iterator_category = decltype(_S_iter_cat());
- };
- template<bool _Const>
- struct _Sentinel;
- template<bool _Const>
- struct _Iterator : __iter_cat<_Const>
- {
- private:
- using _Parent = __detail::__maybe_const_t<_Const, transform_view>;
- using _Base = transform_view::_Base<_Const>;
- static auto
- _S_iter_concept()
- {
- if constexpr (random_access_range<_Base>)
- return random_access_iterator_tag{};
- else if constexpr (bidirectional_range<_Base>)
- return bidirectional_iterator_tag{};
- else if constexpr (forward_range<_Base>)
- return forward_iterator_tag{};
- else
- return input_iterator_tag{};
- }
- using _Base_iter = iterator_t<_Base>;
- _Base_iter _M_current = _Base_iter();
- _Parent* _M_parent = nullptr;
- public:
- using iterator_concept = decltype(_S_iter_concept());
- // iterator_category defined in __transform_view_iter_cat
- using value_type
- = remove_cvref_t<invoke_result_t<_Fp&, range_reference_t<_Base>>>;
- using difference_type = range_difference_t<_Base>;
- _Iterator() requires default_initializable<_Base_iter> = default;
- constexpr
- _Iterator(_Parent* __parent, _Base_iter __current)
- : _M_current(std::move(__current)),
- _M_parent(__parent)
- { }
- constexpr
- _Iterator(_Iterator<!_Const> __i)
- requires _Const
- && convertible_to<iterator_t<_Vp>, _Base_iter>
- : _M_current(std::move(__i._M_current)), _M_parent(__i._M_parent)
- { }
- constexpr const _Base_iter&
- base() const & noexcept
- { return _M_current; }
- constexpr _Base_iter
- base() &&
- { return std::move(_M_current); }
- constexpr decltype(auto)
- operator*() const
- noexcept(noexcept(std::__invoke(*_M_parent->_M_fun, *_M_current)))
- { return std::__invoke(*_M_parent->_M_fun, *_M_current); }
- constexpr _Iterator&
- operator++()
- {
- ++_M_current;
- return *this;
- }
- constexpr void
- operator++(int)
- { ++_M_current; }
- constexpr _Iterator
- operator++(int) requires forward_range<_Base>
- {
- auto __tmp = *this;
- ++*this;
- return __tmp;
- }
- constexpr _Iterator&
- operator--() requires bidirectional_range<_Base>
- {
- --_M_current;
- return *this;
- }
- constexpr _Iterator
- operator--(int) requires bidirectional_range<_Base>
- {
- auto __tmp = *this;
- --*this;
- return __tmp;
- }
- constexpr _Iterator&
- operator+=(difference_type __n) requires random_access_range<_Base>
- {
- _M_current += __n;
- return *this;
- }
- constexpr _Iterator&
- operator-=(difference_type __n) requires random_access_range<_Base>
- {
- _M_current -= __n;
- return *this;
- }
- constexpr decltype(auto)
- operator[](difference_type __n) const
- requires random_access_range<_Base>
- { return std::__invoke(*_M_parent->_M_fun, _M_current[__n]); }
- friend constexpr bool
- operator==(const _Iterator& __x, const _Iterator& __y)
- requires equality_comparable<_Base_iter>
- { return __x._M_current == __y._M_current; }
- friend constexpr bool
- operator<(const _Iterator& __x, const _Iterator& __y)
- requires random_access_range<_Base>
- { return __x._M_current < __y._M_current; }
- friend constexpr bool
- operator>(const _Iterator& __x, const _Iterator& __y)
- requires random_access_range<_Base>
- { return __y < __x; }
- friend constexpr bool
- operator<=(const _Iterator& __x, const _Iterator& __y)
- requires random_access_range<_Base>
- { return !(__y < __x); }
- friend constexpr bool
- operator>=(const _Iterator& __x, const _Iterator& __y)
- requires random_access_range<_Base>
- { return !(__x < __y); }
- #ifdef __cpp_lib_three_way_comparison
- friend constexpr auto
- operator<=>(const _Iterator& __x, const _Iterator& __y)
- requires random_access_range<_Base>
- && three_way_comparable<_Base_iter>
- { return __x._M_current <=> __y._M_current; }
- #endif
- friend constexpr _Iterator
- operator+(_Iterator __i, difference_type __n)
- requires random_access_range<_Base>
- { return {__i._M_parent, __i._M_current + __n}; }
- friend constexpr _Iterator
- operator+(difference_type __n, _Iterator __i)
- requires random_access_range<_Base>
- { return {__i._M_parent, __i._M_current + __n}; }
- friend constexpr _Iterator
- operator-(_Iterator __i, difference_type __n)
- requires random_access_range<_Base>
- { return {__i._M_parent, __i._M_current - __n}; }
- // _GLIBCXX_RESOLVE_LIB_DEFECTS
- // 3483. transform_view::iterator's difference is overconstrained
- friend constexpr difference_type
- operator-(const _Iterator& __x, const _Iterator& __y)
- requires sized_sentinel_for<iterator_t<_Base>, iterator_t<_Base>>
- { return __x._M_current - __y._M_current; }
- friend constexpr decltype(auto)
- iter_move(const _Iterator& __i) noexcept(noexcept(*__i))
- {
- if constexpr (is_lvalue_reference_v<decltype(*__i)>)
- return std::move(*__i);
- else
- return *__i;
- }
- friend _Iterator<!_Const>;
- template<bool> friend struct _Sentinel;
- };
- template<bool _Const>
- struct _Sentinel
- {
- private:
- using _Parent = __detail::__maybe_const_t<_Const, transform_view>;
- using _Base = transform_view::_Base<_Const>;
- template<bool _Const2>
- constexpr auto
- __distance_from(const _Iterator<_Const2>& __i) const
- { return _M_end - __i._M_current; }
- template<bool _Const2>
- constexpr bool
- __equal(const _Iterator<_Const2>& __i) const
- { return __i._M_current == _M_end; }
- sentinel_t<_Base> _M_end = sentinel_t<_Base>();
- public:
- _Sentinel() = default;
- constexpr explicit
- _Sentinel(sentinel_t<_Base> __end)
- : _M_end(__end)
- { }
- constexpr
- _Sentinel(_Sentinel<!_Const> __i)
- requires _Const
- && convertible_to<sentinel_t<_Vp>, sentinel_t<_Base>>
- : _M_end(std::move(__i._M_end))
- { }
- constexpr sentinel_t<_Base>
- base() const
- { return _M_end; }
- template<bool _Const2>
- requires sentinel_for<sentinel_t<_Base>,
- iterator_t<__detail::__maybe_const_t<_Const2, _Vp>>>
- friend constexpr bool
- operator==(const _Iterator<_Const2>& __x, const _Sentinel& __y)
- { return __y.__equal(__x); }
- template<bool _Const2,
- typename _Base2 = __detail::__maybe_const_t<_Const2, _Vp>>
- requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<_Base2>>
- friend constexpr range_difference_t<_Base2>
- operator-(const _Iterator<_Const2>& __x, const _Sentinel& __y)
- { return -__y.__distance_from(__x); }
- template<bool _Const2,
- typename _Base2 = __detail::__maybe_const_t<_Const2, _Vp>>
- requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<_Base2>>
- friend constexpr range_difference_t<_Base2>
- operator-(const _Sentinel& __y, const _Iterator<_Const2>& __x)
- { return __y.__distance_from(__x); }
- friend _Sentinel<!_Const>;
- };
- _Vp _M_base = _Vp();
- [[no_unique_address]] __detail::__box<_Fp> _M_fun;
- public:
- transform_view() requires (default_initializable<_Vp>
- && default_initializable<_Fp>)
- = default;
- constexpr
- transform_view(_Vp __base, _Fp __fun)
- : _M_base(std::move(__base)), _M_fun(std::move(__fun))
- { }
- constexpr _Vp
- base() const& requires copy_constructible<_Vp>
- { return _M_base ; }
- constexpr _Vp
- base() &&
- { return std::move(_M_base); }
- constexpr _Iterator<false>
- begin()
- { return _Iterator<false>{this, ranges::begin(_M_base)}; }
- constexpr _Iterator<true>
- begin() const
- requires range<const _Vp>
- && regular_invocable<const _Fp&, range_reference_t<const _Vp>>
- { return _Iterator<true>{this, ranges::begin(_M_base)}; }
- constexpr _Sentinel<false>
- end()
- { return _Sentinel<false>{ranges::end(_M_base)}; }
- constexpr _Iterator<false>
- end() requires common_range<_Vp>
- { return _Iterator<false>{this, ranges::end(_M_base)}; }
- constexpr _Sentinel<true>
- end() const
- requires range<const _Vp>
- && regular_invocable<const _Fp&, range_reference_t<const _Vp>>
- { return _Sentinel<true>{ranges::end(_M_base)}; }
- constexpr _Iterator<true>
- end() const
- requires common_range<const _Vp>
- && regular_invocable<const _Fp&, range_reference_t<const _Vp>>
- { return _Iterator<true>{this, ranges::end(_M_base)}; }
- constexpr auto
- size() requires sized_range<_Vp>
- { return ranges::size(_M_base); }
- constexpr auto
- size() const requires sized_range<const _Vp>
- { return ranges::size(_M_base); }
- };
- template<typename _Range, typename _Fp>
- transform_view(_Range&&, _Fp) -> transform_view<views::all_t<_Range>, _Fp>;
- namespace views
- {
- namespace __detail
- {
- template<typename _Range, typename _Fp>
- concept __can_transform_view
- = requires { transform_view(std::declval<_Range>(), std::declval<_Fp>()); };
- } // namespace __detail
- struct _Transform : __adaptor::_RangeAdaptor<_Transform>
- {
- template<viewable_range _Range, typename _Fp>
- requires __detail::__can_transform_view<_Range, _Fp>
- constexpr auto
- operator() [[nodiscard]] (_Range&& __r, _Fp&& __f) const
- {
- return transform_view(std::forward<_Range>(__r), std::forward<_Fp>(__f));
- }
- using _RangeAdaptor<_Transform>::operator();
- static constexpr int _S_arity = 2;
- static constexpr bool _S_has_simple_extra_args = true;
- };
- inline constexpr _Transform transform;
- } // namespace views
- template<view _Vp>
- class take_view : public view_interface<take_view<_Vp>>
- {
- private:
- template<bool _Const>
- using _CI = counted_iterator<
- iterator_t<__detail::__maybe_const_t<_Const, _Vp>>>;
- template<bool _Const>
- struct _Sentinel
- {
- private:
- using _Base = __detail::__maybe_const_t<_Const, _Vp>;
- sentinel_t<_Base> _M_end = sentinel_t<_Base>();
- public:
- _Sentinel() = default;
- constexpr explicit
- _Sentinel(sentinel_t<_Base> __end)
- : _M_end(__end)
- { }
- constexpr
- _Sentinel(_Sentinel<!_Const> __s)
- requires _Const && convertible_to<sentinel_t<_Vp>, sentinel_t<_Base>>
- : _M_end(std::move(__s._M_end))
- { }
- constexpr sentinel_t<_Base>
- base() const
- { return _M_end; }
- friend constexpr bool
- operator==(const _CI<_Const>& __y, const _Sentinel& __x)
- { return __y.count() == 0 || __y.base() == __x._M_end; }
- template<bool _OtherConst = !_Const,
- typename _Base2 = __detail::__maybe_const_t<_OtherConst, _Vp>>
- requires sentinel_for<sentinel_t<_Base>, iterator_t<_Base2>>
- friend constexpr bool
- operator==(const _CI<_OtherConst>& __y, const _Sentinel& __x)
- { return __y.count() == 0 || __y.base() == __x._M_end; }
- friend _Sentinel<!_Const>;
- };
- _Vp _M_base = _Vp();
- range_difference_t<_Vp> _M_count = 0;
- public:
- take_view() requires default_initializable<_Vp> = default;
- constexpr
- take_view(_Vp base, range_difference_t<_Vp> __count)
- : _M_base(std::move(base)), _M_count(std::move(__count))
- { }
- constexpr _Vp
- base() const& requires copy_constructible<_Vp>
- { return _M_base; }
- constexpr _Vp
- base() &&
- { return std::move(_M_base); }
- constexpr auto
- begin() requires (!__detail::__simple_view<_Vp>)
- {
- if constexpr (sized_range<_Vp>)
- {
- if constexpr (random_access_range<_Vp>)
- return ranges::begin(_M_base);
- else
- {
- auto __sz = size();
- return counted_iterator(ranges::begin(_M_base), __sz);
- }
- }
- else
- return counted_iterator(ranges::begin(_M_base), _M_count);
- }
- constexpr auto
- begin() const requires range<const _Vp>
- {
- if constexpr (sized_range<const _Vp>)
- {
- if constexpr (random_access_range<const _Vp>)
- return ranges::begin(_M_base);
- else
- {
- auto __sz = size();
- return counted_iterator(ranges::begin(_M_base), __sz);
- }
- }
- else
- return counted_iterator(ranges::begin(_M_base), _M_count);
- }
- constexpr auto
- end() requires (!__detail::__simple_view<_Vp>)
- {
- if constexpr (sized_range<_Vp>)
- {
- if constexpr (random_access_range<_Vp>)
- return ranges::begin(_M_base) + size();
- else
- return default_sentinel;
- }
- else
- return _Sentinel<false>{ranges::end(_M_base)};
- }
- constexpr auto
- end() const requires range<const _Vp>
- {
- if constexpr (sized_range<const _Vp>)
- {
- if constexpr (random_access_range<const _Vp>)
- return ranges::begin(_M_base) + size();
- else
- return default_sentinel;
- }
- else
- return _Sentinel<true>{ranges::end(_M_base)};
- }
- constexpr auto
- size() requires sized_range<_Vp>
- {
- auto __n = ranges::size(_M_base);
- return std::min(__n, static_cast<decltype(__n)>(_M_count));
- }
- constexpr auto
- size() const requires sized_range<const _Vp>
- {
- auto __n = ranges::size(_M_base);
- return std::min(__n, static_cast<decltype(__n)>(_M_count));
- }
- };
- // _GLIBCXX_RESOLVE_LIB_DEFECTS
- // 3447. Deduction guides for take_view and drop_view have different
- // constraints
- template<typename _Range>
- take_view(_Range&&, range_difference_t<_Range>)
- -> take_view<views::all_t<_Range>>;
- template<typename _Tp>
- inline constexpr bool enable_borrowed_range<take_view<_Tp>>
- = enable_borrowed_range<_Tp>;
- namespace views
- {
- namespace __detail
- {
- template<typename _Range>
- inline constexpr bool __is_empty_view = false;
- template<typename _Tp>
- inline constexpr bool __is_empty_view<empty_view<_Tp>> = true;
- template<typename _Range>
- inline constexpr bool __is_basic_string_view = false;
- template<typename _CharT, typename _Traits>
- inline constexpr bool __is_basic_string_view<basic_string_view<_CharT, _Traits>>
- = true;
- template<typename _Range>
- inline constexpr bool __is_subrange = false;
- template<typename _Iter, typename _Sent, subrange_kind _Kind>
- inline constexpr bool __is_subrange<subrange<_Iter, _Sent, _Kind>> = true;
- template<typename _Range>
- inline constexpr bool __is_iota_view = false;
- template<typename _Winc, typename _Bound>
- inline constexpr bool __is_iota_view<iota_view<_Winc, _Bound>> = true;
- template<typename _Range, typename _Dp>
- concept __can_take_view
- = requires { take_view(std::declval<_Range>(), std::declval<_Dp>()); };
- } // namespace __detail
- struct _Take : __adaptor::_RangeAdaptor<_Take>
- {
- template<viewable_range _Range, typename _Dp = range_difference_t<_Range>>
- requires __detail::__can_take_view<_Range, _Dp>
- constexpr auto
- operator() [[nodiscard]] (_Range&& __r, type_identity_t<_Dp> __n) const
- {
- using _Tp = remove_cvref_t<_Range>;
- if constexpr (__detail::__is_empty_view<_Tp>)
- return _Tp();
- else if constexpr (random_access_range<_Tp>
- && sized_range<_Tp>
- && (std::__detail::__is_span<_Tp>
- || __detail::__is_basic_string_view<_Tp>
- || __detail::__is_subrange<_Tp>
- || __detail::__is_iota_view<_Tp>))
- {
- __n = std::min<_Dp>(ranges::distance(__r), __n);
- auto __begin = ranges::begin(__r);
- auto __end = __begin + __n;
- if constexpr (std::__detail::__is_span<_Tp>)
- return span<typename _Tp::element_type>(__begin, __end);
- else if constexpr (__detail::__is_basic_string_view<_Tp>)
- return _Tp(__begin, __end);
- else if constexpr (__detail::__is_subrange<_Tp>)
- return subrange<iterator_t<_Tp>>(__begin, __end);
- else
- return iota_view(*__begin, *__end);
- }
- else
- return take_view(std::forward<_Range>(__r), __n);
- }
- using _RangeAdaptor<_Take>::operator();
- static constexpr int _S_arity = 2;
- // The count argument of views::take is not always simple -- it can be
- // e.g. a move-only class that's implicitly convertible to the difference
- // type. But an integer-like count argument is surely simple.
- template<typename _Tp>
- static constexpr bool _S_has_simple_extra_args
- = ranges::__detail::__is_integer_like<_Tp>;
- };
- inline constexpr _Take take;
- } // namespace views
- template<view _Vp, typename _Pred>
- requires input_range<_Vp> && is_object_v<_Pred>
- && indirect_unary_predicate<const _Pred, iterator_t<_Vp>>
- class take_while_view : public view_interface<take_while_view<_Vp, _Pred>>
- {
- template<bool _Const>
- struct _Sentinel
- {
- private:
- using _Base = __detail::__maybe_const_t<_Const, _Vp>;
- sentinel_t<_Base> _M_end = sentinel_t<_Base>();
- const _Pred* _M_pred = nullptr;
- public:
- _Sentinel() = default;
- constexpr explicit
- _Sentinel(sentinel_t<_Base> __end, const _Pred* __pred)
- : _M_end(__end), _M_pred(__pred)
- { }
- constexpr
- _Sentinel(_Sentinel<!_Const> __s)
- requires _Const && convertible_to<sentinel_t<_Vp>, sentinel_t<_Base>>
- : _M_end(__s._M_end), _M_pred(__s._M_pred)
- { }
- constexpr sentinel_t<_Base>
- base() const { return _M_end; }
- friend constexpr bool
- operator==(const iterator_t<_Base>& __x, const _Sentinel& __y)
- { return __y._M_end == __x || !std::__invoke(*__y._M_pred, *__x); }
- template<bool _OtherConst = !_Const,
- typename _Base2 = __detail::__maybe_const_t<_OtherConst, _Vp>>
- requires sentinel_for<sentinel_t<_Base>, iterator_t<_Base2>>
- friend constexpr bool
- operator==(const iterator_t<_Base2>& __x, const _Sentinel& __y)
- { return __y._M_end == __x || !std::__invoke(*__y._M_pred, *__x); }
- friend _Sentinel<!_Const>;
- };
- _Vp _M_base = _Vp();
- [[no_unique_address]] __detail::__box<_Pred> _M_pred;
- public:
- take_while_view() requires (default_initializable<_Vp>
- && default_initializable<_Pred>)
- = default;
- constexpr
- take_while_view(_Vp base, _Pred __pred)
- : _M_base(std::move(base)), _M_pred(std::move(__pred))
- { }
- constexpr _Vp
- base() const& requires copy_constructible<_Vp>
- { return _M_base; }
- constexpr _Vp
- base() &&
- { return std::move(_M_base); }
- constexpr const _Pred&
- pred() const
- { return *_M_pred; }
- constexpr auto
- begin() requires (!__detail::__simple_view<_Vp>)
- { return ranges::begin(_M_base); }
- constexpr auto
- begin() const requires range<const _Vp>
- && indirect_unary_predicate<const _Pred, iterator_t<const _Vp>>
- { return ranges::begin(_M_base); }
- constexpr auto
- end() requires (!__detail::__simple_view<_Vp>)
- { return _Sentinel<false>(ranges::end(_M_base),
- std::__addressof(*_M_pred)); }
- constexpr auto
- end() const requires range<const _Vp>
- && indirect_unary_predicate<const _Pred, iterator_t<const _Vp>>
- { return _Sentinel<true>(ranges::end(_M_base),
- std::__addressof(*_M_pred)); }
- };
- template<typename _Range, typename _Pred>
- take_while_view(_Range&&, _Pred)
- -> take_while_view<views::all_t<_Range>, _Pred>;
- namespace views
- {
- namespace __detail
- {
- template<typename _Range, typename _Pred>
- concept __can_take_while_view
- = requires { take_while_view(std::declval<_Range>(), std::declval<_Pred>()); };
- } // namespace __detail
- struct _TakeWhile : __adaptor::_RangeAdaptor<_TakeWhile>
- {
- template<viewable_range _Range, typename _Pred>
- requires __detail::__can_take_while_view<_Range, _Pred>
- constexpr auto
- operator() [[nodiscard]] (_Range&& __r, _Pred&& __p) const
- {
- return take_while_view(std::forward<_Range>(__r), std::forward<_Pred>(__p));
- }
- using _RangeAdaptor<_TakeWhile>::operator();
- static constexpr int _S_arity = 2;
- static constexpr bool _S_has_simple_extra_args = true;
- };
- inline constexpr _TakeWhile take_while;
- } // namespace views
- template<view _Vp>
- class drop_view : public view_interface<drop_view<_Vp>>
- {
- private:
- _Vp _M_base = _Vp();
- range_difference_t<_Vp> _M_count = 0;
- // ranges::next(begin(base), count, end(base)) is O(1) if _Vp satisfies
- // both random_access_range and sized_range. Otherwise, cache its result.
- static constexpr bool _S_needs_cached_begin
- = !(random_access_range<const _Vp> && sized_range<const _Vp>);
- [[no_unique_address]]
- __detail::__maybe_present_t<_S_needs_cached_begin,
- __detail::_CachedPosition<_Vp>>
- _M_cached_begin;
- public:
- drop_view() requires default_initializable<_Vp> = default;
- constexpr
- drop_view(_Vp __base, range_difference_t<_Vp> __count)
- : _M_base(std::move(__base)), _M_count(__count)
- { __glibcxx_assert(__count >= 0); }
- constexpr _Vp
- base() const& requires copy_constructible<_Vp>
- { return _M_base; }
- constexpr _Vp
- base() &&
- { return std::move(_M_base); }
- // This overload is disabled for simple views with constant-time begin().
- constexpr auto
- begin()
- requires (!(__detail::__simple_view<_Vp>
- && random_access_range<const _Vp>
- && sized_range<const _Vp>))
- {
- if constexpr (_S_needs_cached_begin)
- if (_M_cached_begin._M_has_value())
- return _M_cached_begin._M_get(_M_base);
- auto __it = ranges::next(ranges::begin(_M_base),
- _M_count, ranges::end(_M_base));
- if constexpr (_S_needs_cached_begin)
- _M_cached_begin._M_set(_M_base, __it);
- return __it;
- }
- // _GLIBCXX_RESOLVE_LIB_DEFECTS
- // 3482. drop_view's const begin should additionally require sized_range
- constexpr auto
- begin() const
- requires random_access_range<const _Vp> && sized_range<const _Vp>
- {
- return ranges::next(ranges::begin(_M_base), _M_count,
- ranges::end(_M_base));
- }
- constexpr auto
- end() requires (!__detail::__simple_view<_Vp>)
- { return ranges::end(_M_base); }
- constexpr auto
- end() const requires range<const _Vp>
- { return ranges::end(_M_base); }
- constexpr auto
- size() requires sized_range<_Vp>
- {
- const auto __s = ranges::size(_M_base);
- const auto __c = static_cast<decltype(__s)>(_M_count);
- return __s < __c ? 0 : __s - __c;
- }
- constexpr auto
- size() const requires sized_range<const _Vp>
- {
- const auto __s = ranges::size(_M_base);
- const auto __c = static_cast<decltype(__s)>(_M_count);
- return __s < __c ? 0 : __s - __c;
- }
- };
- template<typename _Range>
- drop_view(_Range&&, range_difference_t<_Range>)
- -> drop_view<views::all_t<_Range>>;
- template<typename _Tp>
- inline constexpr bool enable_borrowed_range<drop_view<_Tp>>
- = enable_borrowed_range<_Tp>;
- namespace views
- {
- namespace __detail
- {
- template<typename _Range, typename _Dp>
- concept __can_drop_view
- = requires { drop_view(std::declval<_Range>(), std::declval<_Dp>()); };
- } // namespace __detail
- struct _Drop : __adaptor::_RangeAdaptor<_Drop>
- {
- template<viewable_range _Range, typename _Dp = range_difference_t<_Range>>
- requires __detail::__can_drop_view<_Range, _Dp>
- constexpr auto
- operator() [[nodiscard]] (_Range&& __r, type_identity_t<_Dp> __n) const
- {
- using _Tp = remove_cvref_t<_Range>;
- if constexpr (__detail::__is_empty_view<_Tp>)
- return _Tp();
- else if constexpr (random_access_range<_Tp>
- && sized_range<_Tp>
- && (std::__detail::__is_span<_Tp>
- || __detail::__is_basic_string_view<_Tp>
- || __detail::__is_iota_view<_Tp>
- || __detail::__is_subrange<_Tp>))
- {
- __n = std::min<_Dp>(ranges::distance(__r), __n);
- auto __begin = ranges::begin(__r) + __n;
- auto __end = ranges::end(__r);
- if constexpr (std::__detail::__is_span<_Tp>)
- return span<typename _Tp::element_type>(__begin, __end);
- else if constexpr (__detail::__is_subrange<_Tp>)
- {
- if constexpr (_Tp::_S_store_size)
- {
- using ranges::__detail::__to_unsigned_like;
- auto __m = ranges::distance(__r) - __n;
- return _Tp(__begin, __end, __to_unsigned_like(__m));
- }
- else
- return _Tp(__begin, __end);
- }
- else
- return _Tp(__begin, __end);
- }
- else
- return drop_view(std::forward<_Range>(__r), __n);
- }
- using _RangeAdaptor<_Drop>::operator();
- static constexpr int _S_arity = 2;
- template<typename _Tp>
- static constexpr bool _S_has_simple_extra_args
- = _Take::_S_has_simple_extra_args<_Tp>;
- };
- inline constexpr _Drop drop;
- } // namespace views
- template<view _Vp, typename _Pred>
- requires input_range<_Vp> && is_object_v<_Pred>
- && indirect_unary_predicate<const _Pred, iterator_t<_Vp>>
- class drop_while_view : public view_interface<drop_while_view<_Vp, _Pred>>
- {
- private:
- _Vp _M_base = _Vp();
- [[no_unique_address]] __detail::__box<_Pred> _M_pred;
- [[no_unique_address]] __detail::_CachedPosition<_Vp> _M_cached_begin;
- public:
- drop_while_view() requires (default_initializable<_Vp>
- && default_initializable<_Pred>)
- = default;
- constexpr
- drop_while_view(_Vp __base, _Pred __pred)
- : _M_base(std::move(__base)), _M_pred(std::move(__pred))
- { }
- constexpr _Vp
- base() const& requires copy_constructible<_Vp>
- { return _M_base; }
- constexpr _Vp
- base() &&
- { return std::move(_M_base); }
- constexpr const _Pred&
- pred() const
- { return *_M_pred; }
- constexpr auto
- begin()
- {
- if (_M_cached_begin._M_has_value())
- return _M_cached_begin._M_get(_M_base);
- __glibcxx_assert(_M_pred.has_value());
- auto __it = ranges::find_if_not(ranges::begin(_M_base),
- ranges::end(_M_base),
- std::cref(*_M_pred));
- _M_cached_begin._M_set(_M_base, __it);
- return __it;
- }
- constexpr auto
- end()
- { return ranges::end(_M_base); }
- };
- template<typename _Range, typename _Pred>
- drop_while_view(_Range&&, _Pred)
- -> drop_while_view<views::all_t<_Range>, _Pred>;
- template<typename _Tp, typename _Pred>
- inline constexpr bool enable_borrowed_range<drop_while_view<_Tp, _Pred>>
- = enable_borrowed_range<_Tp>;
- namespace views
- {
- namespace __detail
- {
- template<typename _Range, typename _Pred>
- concept __can_drop_while_view
- = requires { drop_while_view(std::declval<_Range>(), std::declval<_Pred>()); };
- } // namespace __detail
- struct _DropWhile : __adaptor::_RangeAdaptor<_DropWhile>
- {
- template<viewable_range _Range, typename _Pred>
- requires __detail::__can_drop_while_view<_Range, _Pred>
- constexpr auto
- operator() [[nodiscard]] (_Range&& __r, _Pred&& __p) const
- {
- return drop_while_view(std::forward<_Range>(__r),
- std::forward<_Pred>(__p));
- }
- using _RangeAdaptor<_DropWhile>::operator();
- static constexpr int _S_arity = 2;
- static constexpr bool _S_has_simple_extra_args = true;
- };
- inline constexpr _DropWhile drop_while;
- } // namespace views
- template<input_range _Vp>
- requires view<_Vp> && input_range<range_reference_t<_Vp>>
- class join_view : public view_interface<join_view<_Vp>>
- {
- private:
- using _InnerRange = range_reference_t<_Vp>;
- template<bool _Const>
- using _Base = __detail::__maybe_const_t<_Const, _Vp>;
- template<bool _Const>
- using _Outer_iter = iterator_t<_Base<_Const>>;
- template<bool _Const>
- using _Inner_iter = iterator_t<range_reference_t<_Base<_Const>>>;
- template<bool _Const>
- static constexpr bool _S_ref_is_glvalue
- = is_reference_v<range_reference_t<_Base<_Const>>>;
- template<bool _Const>
- struct __iter_cat
- { };
- template<bool _Const>
- requires _S_ref_is_glvalue<_Const>
- && forward_range<_Base<_Const>>
- && forward_range<range_reference_t<_Base<_Const>>>
- struct __iter_cat<_Const>
- {
- private:
- static constexpr auto
- _S_iter_cat()
- {
- using _Outer_iter = join_view::_Outer_iter<_Const>;
- using _Inner_iter = join_view::_Inner_iter<_Const>;
- using _OuterCat = typename iterator_traits<_Outer_iter>::iterator_category;
- using _InnerCat = typename iterator_traits<_Inner_iter>::iterator_category;
- if constexpr (derived_from<_OuterCat, bidirectional_iterator_tag>
- && derived_from<_InnerCat, bidirectional_iterator_tag>
- && common_range<range_reference_t<_Base<_Const>>>)
- return bidirectional_iterator_tag{};
- else if constexpr (derived_from<_OuterCat, forward_iterator_tag>
- && derived_from<_InnerCat, forward_iterator_tag>)
- return forward_iterator_tag{};
- else
- return input_iterator_tag{};
- }
- public:
- using iterator_category = decltype(_S_iter_cat());
- };
- template<bool _Const>
- struct _Sentinel;
- template<bool _Const>
- struct _Iterator : __iter_cat<_Const>
- {
- private:
- using _Parent = __detail::__maybe_const_t<_Const, join_view>;
- using _Base = join_view::_Base<_Const>;
- static constexpr bool _S_ref_is_glvalue
- = join_view::_S_ref_is_glvalue<_Const>;
- constexpr void
- _M_satisfy()
- {
- auto __update_inner = [this] (const iterator_t<_Base>& __x) -> auto&& {
- if constexpr (_S_ref_is_glvalue)
- return *__x;
- else
- return _M_parent->_M_inner._M_emplace_deref(__x);
- };
- for (; _M_outer != ranges::end(_M_parent->_M_base); ++_M_outer)
- {
- auto&& __inner = __update_inner(_M_outer);
- _M_inner = ranges::begin(__inner);
- if (_M_inner != ranges::end(__inner))
- return;
- }
- if constexpr (_S_ref_is_glvalue)
- _M_inner = _Inner_iter();
- }
- static constexpr auto
- _S_iter_concept()
- {
- if constexpr (_S_ref_is_glvalue
- && bidirectional_range<_Base>
- && bidirectional_range<range_reference_t<_Base>>
- && common_range<range_reference_t<_Base>>)
- return bidirectional_iterator_tag{};
- else if constexpr (_S_ref_is_glvalue
- && forward_range<_Base>
- && forward_range<range_reference_t<_Base>>)
- return forward_iterator_tag{};
- else
- return input_iterator_tag{};
- }
- using _Outer_iter = join_view::_Outer_iter<_Const>;
- using _Inner_iter = join_view::_Inner_iter<_Const>;
- _Outer_iter _M_outer = _Outer_iter();
- _Inner_iter _M_inner = _Inner_iter();
- _Parent* _M_parent = nullptr;
- public:
- using iterator_concept = decltype(_S_iter_concept());
- // iterator_category defined in __join_view_iter_cat
- using value_type = range_value_t<range_reference_t<_Base>>;
- using difference_type
- = common_type_t<range_difference_t<_Base>,
- range_difference_t<range_reference_t<_Base>>>;
- _Iterator() requires (default_initializable<_Outer_iter>
- && default_initializable<_Inner_iter>)
- = default;
- constexpr
- _Iterator(_Parent* __parent, _Outer_iter __outer)
- : _M_outer(std::move(__outer)),
- _M_parent(__parent)
- { _M_satisfy(); }
- constexpr
- _Iterator(_Iterator<!_Const> __i)
- requires _Const
- && convertible_to<iterator_t<_Vp>, _Outer_iter>
- && convertible_to<iterator_t<_InnerRange>, _Inner_iter>
- : _M_outer(std::move(__i._M_outer)), _M_inner(std::move(__i._M_inner)),
- _M_parent(__i._M_parent)
- { }
- constexpr decltype(auto)
- operator*() const
- { return *_M_inner; }
- // _GLIBCXX_RESOLVE_LIB_DEFECTS
- // 3500. join_view::iterator::operator->() is bogus
- constexpr _Inner_iter
- operator->() const
- requires __detail::__has_arrow<_Inner_iter>
- && copyable<_Inner_iter>
- { return _M_inner; }
- constexpr _Iterator&
- operator++()
- {
- auto&& __inner_range = [this] () -> auto&& {
- if constexpr (_S_ref_is_glvalue)
- return *_M_outer;
- else
- return *_M_parent->_M_inner;
- }();
- if (++_M_inner == ranges::end(__inner_range))
- {
- ++_M_outer;
- _M_satisfy();
- }
- return *this;
- }
- constexpr void
- operator++(int)
- { ++*this; }
- constexpr _Iterator
- operator++(int)
- requires _S_ref_is_glvalue && forward_range<_Base>
- && forward_range<range_reference_t<_Base>>
- {
- auto __tmp = *this;
- ++*this;
- return __tmp;
- }
- constexpr _Iterator&
- operator--()
- requires _S_ref_is_glvalue && bidirectional_range<_Base>
- && bidirectional_range<range_reference_t<_Base>>
- && common_range<range_reference_t<_Base>>
- {
- if (_M_outer == ranges::end(_M_parent->_M_base))
- _M_inner = ranges::end(*--_M_outer);
- while (_M_inner == ranges::begin(*_M_outer))
- _M_inner = ranges::end(*--_M_outer);
- --_M_inner;
- return *this;
- }
- constexpr _Iterator
- operator--(int)
- requires _S_ref_is_glvalue && bidirectional_range<_Base>
- && bidirectional_range<range_reference_t<_Base>>
- && common_range<range_reference_t<_Base>>
- {
- auto __tmp = *this;
- --*this;
- return __tmp;
- }
- friend constexpr bool
- operator==(const _Iterator& __x, const _Iterator& __y)
- requires _S_ref_is_glvalue
- && equality_comparable<_Outer_iter>
- && equality_comparable<_Inner_iter>
- {
- return (__x._M_outer == __y._M_outer
- && __x._M_inner == __y._M_inner);
- }
- friend constexpr decltype(auto)
- iter_move(const _Iterator& __i)
- noexcept(noexcept(ranges::iter_move(__i._M_inner)))
- { return ranges::iter_move(__i._M_inner); }
- friend constexpr void
- iter_swap(const _Iterator& __x, const _Iterator& __y)
- noexcept(noexcept(ranges::iter_swap(__x._M_inner, __y._M_inner)))
- requires indirectly_swappable<_Inner_iter>
- { return ranges::iter_swap(__x._M_inner, __y._M_inner); }
- friend _Iterator<!_Const>;
- template<bool> friend struct _Sentinel;
- };
- template<bool _Const>
- struct _Sentinel
- {
- private:
- using _Parent = __detail::__maybe_const_t<_Const, join_view>;
- using _Base = join_view::_Base<_Const>;
- template<bool _Const2>
- constexpr bool
- __equal(const _Iterator<_Const2>& __i) const
- { return __i._M_outer == _M_end; }
- sentinel_t<_Base> _M_end = sentinel_t<_Base>();
- public:
- _Sentinel() = default;
- constexpr explicit
- _Sentinel(_Parent* __parent)
- : _M_end(ranges::end(__parent->_M_base))
- { }
- constexpr
- _Sentinel(_Sentinel<!_Const> __s)
- requires _Const && convertible_to<sentinel_t<_Vp>, sentinel_t<_Base>>
- : _M_end(std::move(__s._M_end))
- { }
- template<bool _Const2>
- requires sentinel_for<sentinel_t<_Base>,
- iterator_t<__detail::__maybe_const_t<_Const2, _Vp>>>
- friend constexpr bool
- operator==(const _Iterator<_Const2>& __x, const _Sentinel& __y)
- { return __y.__equal(__x); }
- friend _Sentinel<!_Const>;
- };
- _Vp _M_base = _Vp();
- [[no_unique_address]]
- __detail::__non_propagating_cache<remove_cv_t<_InnerRange>> _M_inner;
- public:
- join_view() requires default_initializable<_Vp> = default;
- constexpr explicit
- join_view(_Vp __base)
- : _M_base(std::move(__base))
- { }
- constexpr _Vp
- base() const& requires copy_constructible<_Vp>
- { return _M_base; }
- constexpr _Vp
- base() &&
- { return std::move(_M_base); }
- constexpr auto
- begin()
- {
- constexpr bool __use_const
- = (__detail::__simple_view<_Vp>
- && is_reference_v<range_reference_t<_Vp>>);
- return _Iterator<__use_const>{this, ranges::begin(_M_base)};
- }
- constexpr auto
- begin() const
- requires input_range<const _Vp>
- && is_reference_v<range_reference_t<const _Vp>>
- {
- return _Iterator<true>{this, ranges::begin(_M_base)};
- }
- constexpr auto
- end()
- {
- if constexpr (forward_range<_Vp> && is_reference_v<_InnerRange>
- && forward_range<_InnerRange>
- && common_range<_Vp> && common_range<_InnerRange>)
- return _Iterator<__detail::__simple_view<_Vp>>{this,
- ranges::end(_M_base)};
- else
- return _Sentinel<__detail::__simple_view<_Vp>>{this};
- }
- constexpr auto
- end() const
- requires input_range<const _Vp>
- && is_reference_v<range_reference_t<const _Vp>>
- {
- if constexpr (forward_range<const _Vp>
- && is_reference_v<range_reference_t<const _Vp>>
- && forward_range<range_reference_t<const _Vp>>
- && common_range<const _Vp>
- && common_range<range_reference_t<const _Vp>>)
- return _Iterator<true>{this, ranges::end(_M_base)};
- else
- return _Sentinel<true>{this};
- }
- };
- template<typename _Range>
- explicit join_view(_Range&&) -> join_view<views::all_t<_Range>>;
- namespace views
- {
- namespace __detail
- {
- template<typename _Range>
- concept __can_join_view
- = requires { join_view<all_t<_Range>>{std::declval<_Range>()}; };
- } // namespace __detail
- struct _Join : __adaptor::_RangeAdaptorClosure
- {
- template<viewable_range _Range>
- requires __detail::__can_join_view<_Range>
- constexpr auto
- operator() [[nodiscard]] (_Range&& __r) const
- {
- // _GLIBCXX_RESOLVE_LIB_DEFECTS
- // 3474. Nesting join_views is broken because of CTAD
- return join_view<all_t<_Range>>{std::forward<_Range>(__r)};
- }
- static constexpr bool _S_has_simple_call_op = true;
- };
- inline constexpr _Join join;
- } // namespace views
- namespace __detail
- {
- template<auto>
- struct __require_constant;
- template<typename _Range>
- concept __tiny_range = sized_range<_Range>
- && requires
- { typename __require_constant<remove_reference_t<_Range>::size()>; }
- && (remove_reference_t<_Range>::size() <= 1);
- template<typename _Base>
- struct __lazy_split_view_outer_iter_cat
- { };
- template<forward_range _Base>
- struct __lazy_split_view_outer_iter_cat<_Base>
- { using iterator_category = input_iterator_tag; };
- template<typename _Base>
- struct __lazy_split_view_inner_iter_cat
- { };
- template<forward_range _Base>
- struct __lazy_split_view_inner_iter_cat<_Base>
- {
- private:
- static constexpr auto
- _S_iter_cat()
- {
- using _Cat = typename iterator_traits<iterator_t<_Base>>::iterator_category;
- if constexpr (derived_from<_Cat, forward_iterator_tag>)
- return forward_iterator_tag{};
- else
- return _Cat{};
- }
- public:
- using iterator_category = decltype(_S_iter_cat());
- };
- }
- template<input_range _Vp, forward_range _Pattern>
- requires view<_Vp> && view<_Pattern>
- && indirectly_comparable<iterator_t<_Vp>, iterator_t<_Pattern>,
- ranges::equal_to>
- && (forward_range<_Vp> || __detail::__tiny_range<_Pattern>)
- class lazy_split_view : public view_interface<lazy_split_view<_Vp, _Pattern>>
- {
- private:
- template<bool _Const>
- using _Base = __detail::__maybe_const_t<_Const, _Vp>;
- template<bool _Const>
- struct _InnerIter;
- template<bool _Const>
- struct _OuterIter
- : __detail::__lazy_split_view_outer_iter_cat<_Base<_Const>>
- {
- private:
- using _Parent = __detail::__maybe_const_t<_Const, lazy_split_view>;
- using _Base = lazy_split_view::_Base<_Const>;
- constexpr bool
- __at_end() const
- { return __current() == ranges::end(_M_parent->_M_base) && !_M_trailing_empty; }
- // [range.lazy.split.outer] p1
- // Many of the following specifications refer to the notional member
- // current of outer-iterator. current is equivalent to current_ if
- // V models forward_range, and parent_->current_ otherwise.
- constexpr auto&
- __current() noexcept
- {
- if constexpr (forward_range<_Vp>)
- return _M_current;
- else
- return *_M_parent->_M_current;
- }
- constexpr auto&
- __current() const noexcept
- {
- if constexpr (forward_range<_Vp>)
- return _M_current;
- else
- return *_M_parent->_M_current;
- }
- _Parent* _M_parent = nullptr;
- // XXX: _M_current is present only if "V models forward_range"
- [[no_unique_address]]
- __detail::__maybe_present_t<forward_range<_Vp>,
- iterator_t<_Base>> _M_current;
- bool _M_trailing_empty = false;
- public:
- using iterator_concept = __conditional_t<forward_range<_Base>,
- forward_iterator_tag,
- input_iterator_tag>;
- // iterator_category defined in __lazy_split_view_outer_iter_cat
- using difference_type = range_difference_t<_Base>;
- struct value_type : view_interface<value_type>
- {
- private:
- _OuterIter _M_i = _OuterIter();
- public:
- value_type() = default;
- constexpr explicit
- value_type(_OuterIter __i)
- : _M_i(std::move(__i))
- { }
- constexpr _InnerIter<_Const>
- begin() const
- { return _InnerIter<_Const>{_M_i}; }
- constexpr default_sentinel_t
- end() const noexcept
- { return default_sentinel; }
- };
- _OuterIter() = default;
- constexpr explicit
- _OuterIter(_Parent* __parent) requires (!forward_range<_Base>)
- : _M_parent(__parent)
- { }
- constexpr
- _OuterIter(_Parent* __parent, iterator_t<_Base> __current)
- requires forward_range<_Base>
- : _M_parent(__parent),
- _M_current(std::move(__current))
- { }
- constexpr
- _OuterIter(_OuterIter<!_Const> __i)
- requires _Const
- && convertible_to<iterator_t<_Vp>, iterator_t<_Base>>
- : _M_parent(__i._M_parent), _M_current(std::move(__i._M_current))
- { }
- constexpr value_type
- operator*() const
- { return value_type{*this}; }
- constexpr _OuterIter&
- operator++()
- {
- // _GLIBCXX_RESOLVE_LIB_DEFECTS
- // 3505. lazy_split_view::outer-iterator::operator++ misspecified
- const auto __end = ranges::end(_M_parent->_M_base);
- if (__current() == __end)
- {
- _M_trailing_empty = false;
- return *this;
- }
- const auto [__pbegin, __pend] = subrange{_M_parent->_M_pattern};
- if (__pbegin == __pend)
- ++__current();
- else if constexpr (__detail::__tiny_range<_Pattern>)
- {
- __current() = ranges::find(std::move(__current()), __end,
- *__pbegin);
- if (__current() != __end)
- {
- ++__current();
- if (__current() == __end)
- _M_trailing_empty = true;
- }
- }
- else
- do
- {
- auto [__b, __p]
- = ranges::mismatch(__current(), __end, __pbegin, __pend);
- if (__p == __pend)
- {
- __current() = __b;
- if (__current() == __end)
- _M_trailing_empty = true;
- break;
- }
- } while (++__current() != __end);
- return *this;
- }
- constexpr decltype(auto)
- operator++(int)
- {
- if constexpr (forward_range<_Base>)
- {
- auto __tmp = *this;
- ++*this;
- return __tmp;
- }
- else
- ++*this;
- }
- friend constexpr bool
- operator==(const _OuterIter& __x, const _OuterIter& __y)
- requires forward_range<_Base>
- {
- return __x._M_current == __y._M_current
- && __x._M_trailing_empty == __y._M_trailing_empty;
- }
- friend constexpr bool
- operator==(const _OuterIter& __x, default_sentinel_t)
- { return __x.__at_end(); };
- friend _OuterIter<!_Const>;
- friend _InnerIter<_Const>;
- };
- template<bool _Const>
- struct _InnerIter
- : __detail::__lazy_split_view_inner_iter_cat<_Base<_Const>>
- {
- private:
- using _Base = lazy_split_view::_Base<_Const>;
- constexpr bool
- __at_end() const
- {
- auto [__pcur, __pend] = subrange{_M_i._M_parent->_M_pattern};
- auto __end = ranges::end(_M_i._M_parent->_M_base);
- if constexpr (__detail::__tiny_range<_Pattern>)
- {
- const auto& __cur = _M_i_current();
- if (__cur == __end)
- return true;
- if (__pcur == __pend)
- return _M_incremented;
- return *__cur == *__pcur;
- }
- else
- {
- auto __cur = _M_i_current();
- if (__cur == __end)
- return true;
- if (__pcur == __pend)
- return _M_incremented;
- do
- {
- if (*__cur != *__pcur)
- return false;
- if (++__pcur == __pend)
- return true;
- } while (++__cur != __end);
- return false;
- }
- }
- constexpr auto&
- _M_i_current() noexcept
- { return _M_i.__current(); }
- constexpr auto&
- _M_i_current() const noexcept
- { return _M_i.__current(); }
- _OuterIter<_Const> _M_i = _OuterIter<_Const>();
- bool _M_incremented = false;
- public:
- using iterator_concept
- = typename _OuterIter<_Const>::iterator_concept;
- // iterator_category defined in __lazy_split_view_inner_iter_cat
- using value_type = range_value_t<_Base>;
- using difference_type = range_difference_t<_Base>;
- _InnerIter() = default;
- constexpr explicit
- _InnerIter(_OuterIter<_Const> __i)
- : _M_i(std::move(__i))
- { }
- constexpr const iterator_t<_Base>&
- base() const& noexcept
- { return _M_i_current(); }
- constexpr iterator_t<_Base>
- base() && requires forward_range<_Vp>
- { return std::move(_M_i_current()); }
- constexpr decltype(auto)
- operator*() const
- { return *_M_i_current(); }
- constexpr _InnerIter&
- operator++()
- {
- _M_incremented = true;
- if constexpr (!forward_range<_Base>)
- if constexpr (_Pattern::size() == 0)
- return *this;
- ++_M_i_current();
- return *this;
- }
- constexpr decltype(auto)
- operator++(int)
- {
- if constexpr (forward_range<_Base>)
- {
- auto __tmp = *this;
- ++*this;
- return __tmp;
- }
- else
- ++*this;
- }
- friend constexpr bool
- operator==(const _InnerIter& __x, const _InnerIter& __y)
- requires forward_range<_Base>
- { return __x._M_i == __y._M_i; }
- friend constexpr bool
- operator==(const _InnerIter& __x, default_sentinel_t)
- { return __x.__at_end(); }
- friend constexpr decltype(auto)
- iter_move(const _InnerIter& __i)
- noexcept(noexcept(ranges::iter_move(__i._M_i_current())))
- { return ranges::iter_move(__i._M_i_current()); }
- friend constexpr void
- iter_swap(const _InnerIter& __x, const _InnerIter& __y)
- noexcept(noexcept(ranges::iter_swap(__x._M_i_current(),
- __y._M_i_current())))
- requires indirectly_swappable<iterator_t<_Base>>
- { ranges::iter_swap(__x._M_i_current(), __y._M_i_current()); }
- };
- _Vp _M_base = _Vp();
- _Pattern _M_pattern = _Pattern();
- // XXX: _M_current is "present only if !forward_range<V>"
- [[no_unique_address]]
- __detail::__maybe_present_t<!forward_range<_Vp>,
- __detail::__non_propagating_cache<iterator_t<_Vp>>> _M_current;
- public:
- lazy_split_view() requires (default_initializable<_Vp>
- && default_initializable<_Pattern>)
- = default;
- constexpr
- lazy_split_view(_Vp __base, _Pattern __pattern)
- : _M_base(std::move(__base)), _M_pattern(std::move(__pattern))
- { }
- template<input_range _Range>
- requires constructible_from<_Vp, views::all_t<_Range>>
- && constructible_from<_Pattern, single_view<range_value_t<_Range>>>
- constexpr
- lazy_split_view(_Range&& __r, range_value_t<_Range> __e)
- : _M_base(views::all(std::forward<_Range>(__r))),
- _M_pattern(views::single(std::move(__e)))
- { }
- constexpr _Vp
- base() const& requires copy_constructible<_Vp>
- { return _M_base; }
- constexpr _Vp
- base() &&
- { return std::move(_M_base); }
- constexpr auto
- begin()
- {
- if constexpr (forward_range<_Vp>)
- {
- constexpr bool __simple
- = __detail::__simple_view<_Vp> && __detail::__simple_view<_Pattern>;
- return _OuterIter<__simple>{this, ranges::begin(_M_base)};
- }
- else
- {
- _M_current = ranges::begin(_M_base);
- return _OuterIter<false>{this};
- }
- }
- constexpr auto
- begin() const requires forward_range<_Vp> && forward_range<const _Vp>
- {
- return _OuterIter<true>{this, ranges::begin(_M_base)};
- }
- constexpr auto
- end() requires forward_range<_Vp> && common_range<_Vp>
- {
- constexpr bool __simple
- = __detail::__simple_view<_Vp> && __detail::__simple_view<_Pattern>;
- return _OuterIter<__simple>{this, ranges::end(_M_base)};
- }
- constexpr auto
- end() const
- {
- if constexpr (forward_range<_Vp>
- && forward_range<const _Vp>
- && common_range<const _Vp>)
- return _OuterIter<true>{this, ranges::end(_M_base)};
- else
- return default_sentinel;
- }
- };
- template<typename _Range, typename _Pattern>
- lazy_split_view(_Range&&, _Pattern&&)
- -> lazy_split_view<views::all_t<_Range>, views::all_t<_Pattern>>;
- template<input_range _Range>
- lazy_split_view(_Range&&, range_value_t<_Range>)
- -> lazy_split_view<views::all_t<_Range>, single_view<range_value_t<_Range>>>;
- namespace views
- {
- namespace __detail
- {
- template<typename _Range, typename _Pattern>
- concept __can_lazy_split_view
- = requires { lazy_split_view(std::declval<_Range>(), std::declval<_Pattern>()); };
- } // namespace __detail
- struct _LazySplit : __adaptor::_RangeAdaptor<_LazySplit>
- {
- template<viewable_range _Range, typename _Pattern>
- requires __detail::__can_lazy_split_view<_Range, _Pattern>
- constexpr auto
- operator() [[nodiscard]] (_Range&& __r, _Pattern&& __f) const
- {
- return lazy_split_view(std::forward<_Range>(__r), std::forward<_Pattern>(__f));
- }
- using _RangeAdaptor<_LazySplit>::operator();
- static constexpr int _S_arity = 2;
- // The pattern argument of views::lazy_split is not always simple -- it can be
- // a non-view range, the value category of which affects whether the call
- // is well-formed. But a scalar or a view pattern argument is surely
- // simple.
- template<typename _Pattern>
- static constexpr bool _S_has_simple_extra_args
- = is_scalar_v<_Pattern> || (view<_Pattern>
- && copy_constructible<_Pattern>);
- };
- inline constexpr _LazySplit lazy_split;
- } // namespace views
- template<forward_range _Vp, forward_range _Pattern>
- requires view<_Vp> && view<_Pattern>
- && indirectly_comparable<iterator_t<_Vp>, iterator_t<_Pattern>,
- ranges::equal_to>
- class split_view : public view_interface<split_view<_Vp, _Pattern>>
- {
- private:
- _Vp _M_base = _Vp();
- _Pattern _M_pattern = _Pattern();
- __detail::__non_propagating_cache<subrange<iterator_t<_Vp>>> _M_cached_begin;
- struct _Iterator;
- struct _Sentinel;
- public:
- split_view() requires (default_initializable<_Vp>
- && default_initializable<_Pattern>)
- = default;
- constexpr
- split_view(_Vp __base, _Pattern __pattern)
- : _M_base(std::move(__base)), _M_pattern(std::move(__pattern))
- { }
- template<forward_range _Range>
- requires constructible_from<_Vp, views::all_t<_Range>>
- && constructible_from<_Pattern, single_view<range_value_t<_Range>>>
- constexpr
- split_view(_Range&& __r, range_value_t<_Range> __e)
- : _M_base(views::all(std::forward<_Range>(__r))),
- _M_pattern(views::single(std::move(__e)))
- { }
- constexpr _Vp
- base() const& requires copy_constructible<_Vp>
- { return _M_base; }
- constexpr _Vp
- base() &&
- { return std::move(_M_base); }
- constexpr _Iterator
- begin()
- {
- if (!_M_cached_begin)
- _M_cached_begin = _M_find_next(ranges::begin(_M_base));
- return {this, ranges::begin(_M_base), *_M_cached_begin};
- }
- constexpr auto
- end()
- {
- if constexpr (common_range<_Vp>)
- return _Iterator{this, ranges::end(_M_base), {}};
- else
- return _Sentinel{this};
- }
- constexpr subrange<iterator_t<_Vp>>
- _M_find_next(iterator_t<_Vp> __it)
- {
- auto [__b, __e] = ranges::search(subrange(__it, ranges::end(_M_base)), _M_pattern);
- if (__b != ranges::end(_M_base) && ranges::empty(_M_pattern))
- {
- ++__b;
- ++__e;
- }
- return {__b, __e};
- }
- private:
- struct _Iterator
- {
- private:
- split_view* _M_parent = nullptr;
- iterator_t<_Vp> _M_cur = iterator_t<_Vp>();
- subrange<iterator_t<_Vp>> _M_next = subrange<iterator_t<_Vp>>();
- bool _M_trailing_empty = false;
- friend struct _Sentinel;
- public:
- using iterator_concept = forward_iterator_tag;
- using iterator_category = input_iterator_tag;
- using value_type = subrange<iterator_t<_Vp>>;
- using difference_type = range_difference_t<_Vp>;
- _Iterator() = default;
- constexpr
- _Iterator(split_view* __parent,
- iterator_t<_Vp> __current,
- subrange<iterator_t<_Vp>> __next)
- : _M_parent(__parent),
- _M_cur(std::move(__current)),
- _M_next(std::move(__next))
- { }
- constexpr iterator_t<_Vp>
- base() const
- { return _M_cur; }
- constexpr value_type
- operator*() const
- { return {_M_cur, _M_next.begin()}; }
- constexpr _Iterator&
- operator++()
- {
- _M_cur = _M_next.begin();
- if (_M_cur != ranges::end(_M_parent->_M_base))
- {
- _M_cur = _M_next.end();
- if (_M_cur == ranges::end(_M_parent->_M_base))
- {
- _M_trailing_empty = true;
- _M_next = {_M_cur, _M_cur};
- }
- else
- _M_next = _M_parent->_M_find_next(_M_cur);
- }
- else
- _M_trailing_empty = false;
- return *this;
- }
- constexpr _Iterator
- operator++(int)
- {
- auto __tmp = *this;
- ++*this;
- return __tmp;
- }
- friend constexpr bool
- operator==(const _Iterator& __x, const _Iterator& __y)
- {
- return __x._M_cur == __y._M_cur
- && __x._M_trailing_empty == __y._M_trailing_empty;
- }
- };
- struct _Sentinel
- {
- private:
- sentinel_t<_Vp> _M_end = sentinel_t<_Vp>();
- constexpr bool
- _M_equal(const _Iterator& __x) const
- { return __x._M_cur == _M_end && !__x._M_trailing_empty; }
- public:
- _Sentinel() = default;
- constexpr explicit
- _Sentinel(split_view* __parent)
- : _M_end(ranges::end(__parent->_M_base))
- { }
- friend constexpr bool
- operator==(const _Iterator& __x, const _Sentinel& __y)
- { return __y._M_equal(__x); }
- };
- };
- template<typename _Range, typename _Pattern>
- split_view(_Range&&, _Pattern&&)
- -> split_view<views::all_t<_Range>, views::all_t<_Pattern>>;
- template<forward_range _Range>
- split_view(_Range&&, range_value_t<_Range>)
- -> split_view<views::all_t<_Range>, single_view<range_value_t<_Range>>>;
- namespace views
- {
- namespace __detail
- {
- template<typename _Range, typename _Pattern>
- concept __can_split_view
- = requires { split_view(std::declval<_Range>(), std::declval<_Pattern>()); };
- } // namespace __detail
- struct _Split : __adaptor::_RangeAdaptor<_Split>
- {
- template<viewable_range _Range, typename _Pattern>
- requires __detail::__can_split_view<_Range, _Pattern>
- constexpr auto
- operator() [[nodiscard]] (_Range&& __r, _Pattern&& __f) const
- {
- return split_view(std::forward<_Range>(__r), std::forward<_Pattern>(__f));
- }
- using _RangeAdaptor<_Split>::operator();
- static constexpr int _S_arity = 2;
- template<typename _Pattern>
- static constexpr bool _S_has_simple_extra_args
- = _LazySplit::_S_has_simple_extra_args<_Pattern>;
- };
- inline constexpr _Split split;
- } // namespace views
- namespace views
- {
- struct _Counted
- {
- template<input_or_output_iterator _Iter>
- constexpr auto
- operator() [[nodiscard]] (_Iter __i, iter_difference_t<_Iter> __n) const
- {
- if constexpr (contiguous_iterator<_Iter>)
- return span(std::__to_address(__i), __n);
- else if constexpr (random_access_iterator<_Iter>)
- return subrange(__i, __i + __n);
- else
- return subrange(counted_iterator(std::move(__i), __n),
- default_sentinel);
- }
- };
- inline constexpr _Counted counted{};
- } // namespace views
- template<view _Vp>
- requires (!common_range<_Vp>) && copyable<iterator_t<_Vp>>
- class common_view : public view_interface<common_view<_Vp>>
- {
- private:
- _Vp _M_base = _Vp();
- public:
- common_view() requires default_initializable<_Vp> = default;
- constexpr explicit
- common_view(_Vp __r)
- : _M_base(std::move(__r))
- { }
- /* XXX: LWG 3280 didn't remove this constructor, but I think it should?
- template<viewable_range _Range>
- requires (!common_range<_Range>)
- && constructible_from<_Vp, views::all_t<_Range>>
- constexpr explicit
- common_view(_Range&& __r)
- : _M_base(views::all(std::forward<_Range>(__r)))
- { }
- */
- constexpr _Vp
- base() const& requires copy_constructible<_Vp>
- { return _M_base; }
- constexpr _Vp
- base() &&
- { return std::move(_M_base); }
- constexpr auto
- begin()
- {
- if constexpr (random_access_range<_Vp> && sized_range<_Vp>)
- return ranges::begin(_M_base);
- else
- return common_iterator<iterator_t<_Vp>, sentinel_t<_Vp>>
- (ranges::begin(_M_base));
- }
- constexpr auto
- begin() const requires range<const _Vp>
- {
- if constexpr (random_access_range<const _Vp> && sized_range<const _Vp>)
- return ranges::begin(_M_base);
- else
- return common_iterator<iterator_t<const _Vp>, sentinel_t<const _Vp>>
- (ranges::begin(_M_base));
- }
- constexpr auto
- end()
- {
- if constexpr (random_access_range<_Vp> && sized_range<_Vp>)
- return ranges::begin(_M_base) + ranges::size(_M_base);
- else
- return common_iterator<iterator_t<_Vp>, sentinel_t<_Vp>>
- (ranges::end(_M_base));
- }
- constexpr auto
- end() const requires range<const _Vp>
- {
- if constexpr (random_access_range<const _Vp> && sized_range<const _Vp>)
- return ranges::begin(_M_base) + ranges::size(_M_base);
- else
- return common_iterator<iterator_t<const _Vp>, sentinel_t<const _Vp>>
- (ranges::end(_M_base));
- }
- constexpr auto
- size() requires sized_range<_Vp>
- { return ranges::size(_M_base); }
- constexpr auto
- size() const requires sized_range<const _Vp>
- { return ranges::size(_M_base); }
- };
- template<typename _Range>
- common_view(_Range&&) -> common_view<views::all_t<_Range>>;
- template<typename _Tp>
- inline constexpr bool enable_borrowed_range<common_view<_Tp>>
- = enable_borrowed_range<_Tp>;
- namespace views
- {
- namespace __detail
- {
- template<typename _Range>
- concept __already_common = common_range<_Range>
- && requires { views::all(std::declval<_Range>()); };
- template<typename _Range>
- concept __can_common_view
- = requires { common_view{std::declval<_Range>()}; };
- } // namespace __detail
- struct _Common : __adaptor::_RangeAdaptorClosure
- {
- template<viewable_range _Range>
- requires __detail::__already_common<_Range>
- || __detail::__can_common_view<_Range>
- constexpr auto
- operator() [[nodiscard]] (_Range&& __r) const
- {
- if constexpr (__detail::__already_common<_Range>)
- return views::all(std::forward<_Range>(__r));
- else
- return common_view{std::forward<_Range>(__r)};
- }
- static constexpr bool _S_has_simple_call_op = true;
- };
- inline constexpr _Common common;
- } // namespace views
- template<view _Vp>
- requires bidirectional_range<_Vp>
- class reverse_view : public view_interface<reverse_view<_Vp>>
- {
- private:
- static constexpr bool _S_needs_cached_begin
- = !common_range<_Vp> && !(random_access_range<_Vp>
- && sized_sentinel_for<sentinel_t<_Vp>,
- iterator_t<_Vp>>);
- _Vp _M_base = _Vp();
- [[no_unique_address]]
- __detail::__maybe_present_t<_S_needs_cached_begin,
- __detail::_CachedPosition<_Vp>>
- _M_cached_begin;
- public:
- reverse_view() requires default_initializable<_Vp> = default;
- constexpr explicit
- reverse_view(_Vp __r)
- : _M_base(std::move(__r))
- { }
- constexpr _Vp
- base() const& requires copy_constructible<_Vp>
- { return _M_base; }
- constexpr _Vp
- base() &&
- { return std::move(_M_base); }
- constexpr reverse_iterator<iterator_t<_Vp>>
- begin()
- {
- if constexpr (_S_needs_cached_begin)
- if (_M_cached_begin._M_has_value())
- return std::make_reverse_iterator(_M_cached_begin._M_get(_M_base));
- auto __it = ranges::next(ranges::begin(_M_base), ranges::end(_M_base));
- if constexpr (_S_needs_cached_begin)
- _M_cached_begin._M_set(_M_base, __it);
- return std::make_reverse_iterator(std::move(__it));
- }
- constexpr auto
- begin() requires common_range<_Vp>
- { return std::make_reverse_iterator(ranges::end(_M_base)); }
- constexpr auto
- begin() const requires common_range<const _Vp>
- { return std::make_reverse_iterator(ranges::end(_M_base)); }
- constexpr reverse_iterator<iterator_t<_Vp>>
- end()
- { return std::make_reverse_iterator(ranges::begin(_M_base)); }
- constexpr auto
- end() const requires common_range<const _Vp>
- { return std::make_reverse_iterator(ranges::begin(_M_base)); }
- constexpr auto
- size() requires sized_range<_Vp>
- { return ranges::size(_M_base); }
- constexpr auto
- size() const requires sized_range<const _Vp>
- { return ranges::size(_M_base); }
- };
- template<typename _Range>
- reverse_view(_Range&&) -> reverse_view<views::all_t<_Range>>;
- template<typename _Tp>
- inline constexpr bool enable_borrowed_range<reverse_view<_Tp>>
- = enable_borrowed_range<_Tp>;
- namespace views
- {
- namespace __detail
- {
- template<typename>
- inline constexpr bool __is_reversible_subrange = false;
- template<typename _Iter, subrange_kind _Kind>
- inline constexpr bool
- __is_reversible_subrange<subrange<reverse_iterator<_Iter>,
- reverse_iterator<_Iter>,
- _Kind>> = true;
- template<typename>
- inline constexpr bool __is_reverse_view = false;
- template<typename _Vp>
- inline constexpr bool __is_reverse_view<reverse_view<_Vp>> = true;
- template<typename _Range>
- concept __can_reverse_view
- = requires { reverse_view{std::declval<_Range>()}; };
- } // namespace __detail
- struct _Reverse : __adaptor::_RangeAdaptorClosure
- {
- template<viewable_range _Range>
- requires __detail::__is_reverse_view<remove_cvref_t<_Range>>
- || __detail::__is_reversible_subrange<remove_cvref_t<_Range>>
- || __detail::__can_reverse_view<_Range>
- constexpr auto
- operator() [[nodiscard]] (_Range&& __r) const
- {
- using _Tp = remove_cvref_t<_Range>;
- if constexpr (__detail::__is_reverse_view<_Tp>)
- return std::forward<_Range>(__r).base();
- else if constexpr (__detail::__is_reversible_subrange<_Tp>)
- {
- using _Iter = decltype(ranges::begin(__r).base());
- if constexpr (sized_range<_Tp>)
- return subrange<_Iter, _Iter, subrange_kind::sized>
- {__r.end().base(), __r.begin().base(), __r.size()};
- else
- return subrange<_Iter, _Iter, subrange_kind::unsized>
- {__r.end().base(), __r.begin().base()};
- }
- else
- return reverse_view{std::forward<_Range>(__r)};
- }
- static constexpr bool _S_has_simple_call_op = true;
- };
- inline constexpr _Reverse reverse;
- } // namespace views
- namespace __detail
- {
- template<typename _Tp, size_t _Nm>
- concept __has_tuple_element = requires(_Tp __t)
- {
- typename tuple_size<_Tp>::type;
- requires _Nm < tuple_size_v<_Tp>;
- typename tuple_element_t<_Nm, _Tp>;
- { std::get<_Nm>(__t) }
- -> convertible_to<const tuple_element_t<_Nm, _Tp>&>;
- };
- template<typename _Tp, size_t _Nm>
- concept __returnable_element
- = is_reference_v<_Tp> || move_constructible<tuple_element_t<_Nm, _Tp>>;
- }
- template<input_range _Vp, size_t _Nm>
- requires view<_Vp>
- && __detail::__has_tuple_element<range_value_t<_Vp>, _Nm>
- && __detail::__has_tuple_element<remove_reference_t<range_reference_t<_Vp>>,
- _Nm>
- && __detail::__returnable_element<range_reference_t<_Vp>, _Nm>
- class elements_view : public view_interface<elements_view<_Vp, _Nm>>
- {
- public:
- elements_view() requires default_initializable<_Vp> = default;
- constexpr explicit
- elements_view(_Vp base)
- : _M_base(std::move(base))
- { }
- constexpr _Vp
- base() const& requires copy_constructible<_Vp>
- { return _M_base; }
- constexpr _Vp
- base() &&
- { return std::move(_M_base); }
- constexpr auto
- begin() requires (!__detail::__simple_view<_Vp>)
- { return _Iterator<false>(ranges::begin(_M_base)); }
- constexpr auto
- begin() const requires range<const _Vp>
- { return _Iterator<true>(ranges::begin(_M_base)); }
- constexpr auto
- end() requires (!__detail::__simple_view<_Vp> && !common_range<_Vp>)
- { return _Sentinel<false>{ranges::end(_M_base)}; }
- constexpr auto
- end() requires (!__detail::__simple_view<_Vp> && common_range<_Vp>)
- { return _Iterator<false>{ranges::end(_M_base)}; }
- constexpr auto
- end() const requires range<const _Vp>
- { return _Sentinel<true>{ranges::end(_M_base)}; }
- constexpr auto
- end() const requires common_range<const _Vp>
- { return _Iterator<true>{ranges::end(_M_base)}; }
- constexpr auto
- size() requires sized_range<_Vp>
- { return ranges::size(_M_base); }
- constexpr auto
- size() const requires sized_range<const _Vp>
- { return ranges::size(_M_base); }
- private:
- template<bool _Const>
- using _Base = __detail::__maybe_const_t<_Const, _Vp>;
- template<bool _Const>
- struct __iter_cat
- { };
- template<bool _Const>
- requires forward_range<_Base<_Const>>
- struct __iter_cat<_Const>
- {
- private:
- static auto _S_iter_cat()
- {
- using _Base = elements_view::_Base<_Const>;
- using _Cat = typename iterator_traits<iterator_t<_Base>>::iterator_category;
- using _Res = decltype((std::get<_Nm>(*std::declval<iterator_t<_Base>>())));
- if constexpr (!is_lvalue_reference_v<_Res>)
- return input_iterator_tag{};
- else if constexpr (derived_from<_Cat, random_access_iterator_tag>)
- return random_access_iterator_tag{};
- else
- return _Cat{};
- }
- public:
- using iterator_category = decltype(_S_iter_cat());
- };
- template<bool _Const>
- struct _Sentinel;
- template<bool _Const>
- struct _Iterator : __iter_cat<_Const>
- {
- private:
- using _Base = elements_view::_Base<_Const>;
- iterator_t<_Base> _M_current = iterator_t<_Base>();
- static constexpr decltype(auto)
- _S_get_element(const iterator_t<_Base>& __i)
- {
- if constexpr (is_reference_v<range_reference_t<_Base>>)
- return std::get<_Nm>(*__i);
- else
- {
- using _Et = remove_cv_t<tuple_element_t<_Nm, range_reference_t<_Base>>>;
- return static_cast<_Et>(std::get<_Nm>(*__i));
- }
- }
- static auto
- _S_iter_concept()
- {
- if constexpr (random_access_range<_Base>)
- return random_access_iterator_tag{};
- else if constexpr (bidirectional_range<_Base>)
- return bidirectional_iterator_tag{};
- else if constexpr (forward_range<_Base>)
- return forward_iterator_tag{};
- else
- return input_iterator_tag{};
- }
- friend _Iterator<!_Const>;
- public:
- using iterator_concept = decltype(_S_iter_concept());
- // iterator_category defined in elements_view::__iter_cat
- using value_type
- = remove_cvref_t<tuple_element_t<_Nm, range_value_t<_Base>>>;
- using difference_type = range_difference_t<_Base>;
- _Iterator() requires default_initializable<iterator_t<_Base>> = default;
- constexpr explicit
- _Iterator(iterator_t<_Base> current)
- : _M_current(std::move(current))
- { }
- constexpr
- _Iterator(_Iterator<!_Const> i)
- requires _Const && convertible_to<iterator_t<_Vp>, iterator_t<_Base>>
- : _M_current(std::move(i._M_current))
- { }
- constexpr const iterator_t<_Base>&
- base() const& noexcept
- { return _M_current; }
- constexpr iterator_t<_Base>
- base() &&
- { return std::move(_M_current); }
- constexpr decltype(auto)
- operator*() const
- { return _S_get_element(_M_current); }
- constexpr _Iterator&
- operator++()
- {
- ++_M_current;
- return *this;
- }
- constexpr void
- operator++(int)
- { ++_M_current; }
- constexpr _Iterator
- operator++(int) requires forward_range<_Base>
- {
- auto __tmp = *this;
- ++_M_current;
- return __tmp;
- }
- constexpr _Iterator&
- operator--() requires bidirectional_range<_Base>
- {
- --_M_current;
- return *this;
- }
- constexpr _Iterator
- operator--(int) requires bidirectional_range<_Base>
- {
- auto __tmp = *this;
- --_M_current;
- return __tmp;
- }
- constexpr _Iterator&
- operator+=(difference_type __n)
- requires random_access_range<_Base>
- {
- _M_current += __n;
- return *this;
- }
- constexpr _Iterator&
- operator-=(difference_type __n)
- requires random_access_range<_Base>
- {
- _M_current -= __n;
- return *this;
- }
- constexpr decltype(auto)
- operator[](difference_type __n) const
- requires random_access_range<_Base>
- { return _S_get_element(_M_current + __n); }
- friend constexpr bool
- operator==(const _Iterator& __x, const _Iterator& __y)
- requires equality_comparable<iterator_t<_Base>>
- { return __x._M_current == __y._M_current; }
- friend constexpr bool
- operator<(const _Iterator& __x, const _Iterator& __y)
- requires random_access_range<_Base>
- { return __x._M_current < __y._M_current; }
- friend constexpr bool
- operator>(const _Iterator& __x, const _Iterator& __y)
- requires random_access_range<_Base>
- { return __y._M_current < __x._M_current; }
- friend constexpr bool
- operator<=(const _Iterator& __x, const _Iterator& __y)
- requires random_access_range<_Base>
- { return !(__y._M_current > __x._M_current); }
- friend constexpr bool
- operator>=(const _Iterator& __x, const _Iterator& __y)
- requires random_access_range<_Base>
- { return !(__x._M_current > __y._M_current); }
- #ifdef __cpp_lib_three_way_comparison
- friend constexpr auto
- operator<=>(const _Iterator& __x, const _Iterator& __y)
- requires random_access_range<_Base>
- && three_way_comparable<iterator_t<_Base>>
- { return __x._M_current <=> __y._M_current; }
- #endif
- friend constexpr _Iterator
- operator+(const _Iterator& __x, difference_type __y)
- requires random_access_range<_Base>
- { return _Iterator{__x} += __y; }
- friend constexpr _Iterator
- operator+(difference_type __x, const _Iterator& __y)
- requires random_access_range<_Base>
- { return __y + __x; }
- friend constexpr _Iterator
- operator-(const _Iterator& __x, difference_type __y)
- requires random_access_range<_Base>
- { return _Iterator{__x} -= __y; }
- // _GLIBCXX_RESOLVE_LIB_DEFECTS
- // 3483. transform_view::iterator's difference is overconstrained
- friend constexpr difference_type
- operator-(const _Iterator& __x, const _Iterator& __y)
- requires sized_sentinel_for<iterator_t<_Base>, iterator_t<_Base>>
- { return __x._M_current - __y._M_current; }
- template <bool> friend struct _Sentinel;
- };
- template<bool _Const>
- struct _Sentinel
- {
- private:
- template<bool _Const2>
- constexpr bool
- _M_equal(const _Iterator<_Const2>& __x) const
- { return __x._M_current == _M_end; }
- template<bool _Const2>
- constexpr auto
- _M_distance_from(const _Iterator<_Const2>& __i) const
- { return _M_end - __i._M_current; }
- using _Base = elements_view::_Base<_Const>;
- sentinel_t<_Base> _M_end = sentinel_t<_Base>();
- public:
- _Sentinel() = default;
- constexpr explicit
- _Sentinel(sentinel_t<_Base> __end)
- : _M_end(std::move(__end))
- { }
- constexpr
- _Sentinel(_Sentinel<!_Const> __other)
- requires _Const
- && convertible_to<sentinel_t<_Vp>, sentinel_t<_Base>>
- : _M_end(std::move(__other._M_end))
- { }
- constexpr sentinel_t<_Base>
- base() const
- { return _M_end; }
- template<bool _Const2>
- requires sentinel_for<sentinel_t<_Base>,
- iterator_t<__detail::__maybe_const_t<_Const2, _Vp>>>
- friend constexpr bool
- operator==(const _Iterator<_Const2>& __x, const _Sentinel& __y)
- { return __y._M_equal(__x); }
- template<bool _Const2,
- typename _Base2 = __detail::__maybe_const_t<_Const2, _Vp>>
- requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<_Base2>>
- friend constexpr range_difference_t<_Base2>
- operator-(const _Iterator<_Const2>& __x, const _Sentinel& __y)
- { return -__y._M_distance_from(__x); }
- template<bool _Const2,
- typename _Base2 = __detail::__maybe_const_t<_Const2, _Vp>>
- requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<_Base2>>
- friend constexpr range_difference_t<_Base2>
- operator-(const _Sentinel& __x, const _Iterator<_Const2>& __y)
- { return __x._M_distance_from(__y); }
- friend _Sentinel<!_Const>;
- };
- _Vp _M_base = _Vp();
- };
- template<typename _Tp, size_t _Nm>
- inline constexpr bool enable_borrowed_range<elements_view<_Tp, _Nm>>
- = enable_borrowed_range<_Tp>;
- template<typename _Range>
- using keys_view = elements_view<views::all_t<_Range>, 0>;
- template<typename _Range>
- using values_view = elements_view<views::all_t<_Range>, 1>;
- namespace views
- {
- namespace __detail
- {
- template<size_t _Nm, typename _Range>
- concept __can_elements_view
- = requires { elements_view<all_t<_Range>, _Nm>{std::declval<_Range>()}; };
- } // namespace __detail
- template<size_t _Nm>
- struct _Elements : __adaptor::_RangeAdaptorClosure
- {
- template<viewable_range _Range>
- requires __detail::__can_elements_view<_Nm, _Range>
- constexpr auto
- operator() [[nodiscard]] (_Range&& __r) const
- {
- return elements_view<all_t<_Range>, _Nm>{std::forward<_Range>(__r)};
- }
- static constexpr bool _S_has_simple_call_op = true;
- };
- template<size_t _Nm>
- inline constexpr _Elements<_Nm> elements;
- inline constexpr auto keys = elements<0>;
- inline constexpr auto values = elements<1>;
- } // namespace views
- } // namespace ranges
- namespace views = ranges::views;
- _GLIBCXX_END_NAMESPACE_VERSION
- } // namespace
- #endif // library concepts
- #endif // C++2a
- #endif /* _GLIBCXX_RANGES */
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