From: Jonathan Wakely <jwakely@redhat.com>
To: Patrick Palka <ppalka@redhat.com>
Cc: gcc-patches@gcc.gnu.org, libstdc++@gcc.gnu.org
Subject: Re: [PATCH] libstdc++: Implement ranges::concat_view from P2542R7
Date: Mon, 29 Apr 2024 10:11:11 +0100 [thread overview]
Message-ID: <CACb0b4kKOYJHbKnok73av_7KFUzHrKkhYepgqb1hn3Hwhc5O5A@mail.gmail.com> (raw)
In-Reply-To: <20240422214231.3530630-1-ppalka@redhat.com>
On Mon, 22 Apr 2024 at 22:43, Patrick Palka wrote:
>
> Tested on x86_64-pc-linux-gnu, does this look OK for trunk? More tests
> are needed but I figured I'd submit this now for possible consideration into
> GCC 14 since we're getting close to release.. All changes are confined to
> C++26.
OK for trunk. Maybe we can backport it for 14.2 later, but not now.
Sorry for the review being slow.
>
> -- >8 --
>
> libstdc++-v3/ChangeLog:
>
> * include/bits/version.def (ranges_concat): Define.
> * include/bits/version.h: Regenerate.
> * include/std/ranges (__detail::__concat_reference_t): Define
> for C++26.
> (__detail::__concat_value_t): Likewise.
> (__detail::__concat_rvalue_reference_t): Likewise.
> (__detail::__concat_indirectly_readable_impl): Likewise.
> (__detail::__concat_indirectly_readable): Likewise.
> (__detail::__concatable): Likewise.
> (__detail::__all_but_last_common): Likewise.
> (__detail::__concat_is_random_access): Likewise.
> (__detail::__concat_is_bidirectional): Likewise.
> (__detail::__last_is_common): Likewise.
> (concat_view): Likewise.
> (__detail::__concat_view_iter_cat): Likewise.
> (concat_view::iterator): Likewise.
> (views::__detail::__can_concat_view): Likewise.
> (views::_Concat, views::concat): Likewise.
> * testsuite/std/ranges/concat/1.cc: New test.
> ---
> libstdc++-v3/include/bits/version.def | 8 +
> libstdc++-v3/include/bits/version.h | 10 +
> libstdc++-v3/include/std/ranges | 584 ++++++++++++++++++
> libstdc++-v3/testsuite/std/ranges/concat/1.cc | 61 ++
> 4 files changed, 663 insertions(+)
> create mode 100644 libstdc++-v3/testsuite/std/ranges/concat/1.cc
>
> diff --git a/libstdc++-v3/include/bits/version.def b/libstdc++-v3/include/bits/version.def
> index 5c0477fb61e..af13090c094 100644
> --- a/libstdc++-v3/include/bits/version.def
> +++ b/libstdc++-v3/include/bits/version.def
> @@ -1796,6 +1796,14 @@ ftms = {
> };
> };
>
> +ftms = {
> + name = ranges_concat;
> + values = {
> + v = 202403;
> + cxxmin = 26;
> + };
> +};
> +
> // Standard test specifications.
> stds[97] = ">= 199711L";
> stds[03] = ">= 199711L";
> diff --git a/libstdc++-v3/include/bits/version.h b/libstdc++-v3/include/bits/version.h
> index 65e708c73fb..1f27bfe050d 100644
> --- a/libstdc++-v3/include/bits/version.h
> +++ b/libstdc++-v3/include/bits/version.h
> @@ -2003,4 +2003,14 @@
> #endif /* !defined(__cpp_lib_to_string) && defined(__glibcxx_want_to_string) */
> #undef __glibcxx_want_to_string
>
> +#if !defined(__cpp_lib_ranges_concat)
> +# if (__cplusplus > 202302L)
> +# define __glibcxx_ranges_concat 202403L
> +# if defined(__glibcxx_want_all) || defined(__glibcxx_want_ranges_concat)
> +# define __cpp_lib_ranges_concat 202403L
> +# endif
> +# endif
> +#endif /* !defined(__cpp_lib_ranges_concat) && defined(__glibcxx_want_ranges_concat) */
> +#undef __glibcxx_want_ranges_concat
> +
> #undef __glibcxx_want_all
> diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges
> index afce818376b..28a39bf6f34 100644
> --- a/libstdc++-v3/include/std/ranges
> +++ b/libstdc++-v3/include/std/ranges
> @@ -55,6 +55,7 @@
> #define __glibcxx_want_ranges_as_const
> #define __glibcxx_want_ranges_as_rvalue
> #define __glibcxx_want_ranges_cartesian_product
> +#define __glibcxx_want_ranges_concat
> #define __glibcxx_want_ranges_chunk
> #define __glibcxx_want_ranges_chunk_by
> #define __glibcxx_want_ranges_enumerate
> @@ -9514,6 +9515,589 @@ namespace __detail
> } // namespace ranges
> #endif // __cpp_lib_ranges_to_container
>
> +#if __cpp_lib_ranges_concat // C++ >= C++26
> +namespace ranges
> +{
> + namespace __detail
> + {
> + template<typename... _Rs>
> + using __concat_reference_t = common_reference_t<range_reference_t<_Rs>...>;
> +
> + template<typename... _Rs>
> + using __concat_value_t = common_type_t<range_value_t<_Rs>...>;
> +
> + template<typename... _Rs>
> + using __concat_rvalue_reference_t
> + = common_reference_t<range_rvalue_reference_t<_Rs>...>;
> +
> + template<typename _Ref, typename _RRef, typename _It>
> + concept __concat_indirectly_readable_impl = requires (const _It __it) {
> + { *__it } -> convertible_to<_Ref>;
> + { ranges::iter_move(__it) } -> convertible_to<_RRef>;
> + };
> +
> + template<typename... _Rs>
> + concept __concat_indirectly_readable
> + = common_reference_with<__concat_reference_t<_Rs...>&&, __concat_value_t<_Rs...>&>
> + && common_reference_with<__concat_reference_t<_Rs...>&&,
> + __concat_rvalue_reference_t<_Rs...>&&>
> + && common_reference_with<__concat_rvalue_reference_t<_Rs...>&&,
> + __concat_value_t<_Rs...> const&>
> + && (__concat_indirectly_readable_impl<__concat_reference_t<_Rs...>,
> + __concat_rvalue_reference_t<_Rs...>,
> + iterator_t<_Rs>>
> + && ...);
> +
> + template<typename... _Rs>
> + concept __concatable = requires {
> + typename __concat_reference_t<_Rs...>;
> + typename __concat_value_t<_Rs...>;
> + typename __concat_rvalue_reference_t<_Rs...>;
> + } && __concat_indirectly_readable<_Rs...>;
> +
> + template<bool _Const, typename _Range, typename... _Rs>
> + struct __all_but_last_common
> + {
> + static inline constexpr bool value
> + = requires { requires (common_range<__maybe_const_t<_Const, _Range>>
> + && __all_but_last_common<_Const, _Rs...>::value); };
> + };
> +
> + template<bool _Const, typename _Range>
> + struct __all_but_last_common<_Const, _Range>
> + { static inline constexpr bool value = true; };
> +
> + template<bool _Const, typename... _Rs>
> + concept __concat_is_random_access = __all_random_access<_Const, _Rs...>
> + && __all_but_last_common<_Const, _Rs...>::value;
> +
> + template<bool _Const, typename... _Rs>
> + concept __concat_is_bidirectional = __all_bidirectional<_Const, _Rs...>
> + && __all_but_last_common<_Const, _Rs...>::value;
> +
> + template<typename _Range, typename... _Rs>
> + struct __last_is_common
> + { static inline constexpr bool value = __last_is_common<_Rs...>::value; };
> +
> + template<typename _Range>
> + struct __last_is_common<_Range>
> + { static inline constexpr bool value = common_range<_Range>; };
> + } // namespace __detail
> +
> + template<input_range... _Vs>
> + requires (view<_Vs> && ...) && (sizeof...(_Vs) > 0) && __detail::__concatable<_Vs...>
> + class concat_view : public view_interface<concat_view<_Vs...>>
> + {
> + tuple<_Vs...> _M_views;
> +
> + template<bool _Const> class iterator;
> +
> + public:
> + constexpr concat_view() = default;
> +
> + constexpr explicit
> + concat_view(_Vs... __views)
> + : _M_views(std::move(__views)...)
> + { }
> +
> + constexpr iterator<false>
> + begin() requires(!(__detail::__simple_view<_Vs> && ...))
> + {
> + iterator<false> __it(this, in_place_index<0>, ranges::begin(std::get<0>(_M_views)));
> + __it.template _M_satisfy<0>();
> + return __it;
> + }
> +
> + constexpr iterator<true>
> + begin() const requires (range<const _Vs> && ...) && __detail::__concatable<const _Vs...>
> + {
> + iterator<true> __it(this, in_place_index<0>, ranges::begin(std::get<0>(_M_views)));
> + __it.template _M_satisfy<0>();
> + return __it;
> + }
> +
> + constexpr auto
> + end() requires(!(__detail::__simple_view<_Vs> && ...))
> + {
> + if constexpr (__detail::__last_is_common<_Vs...>::value)
> + {
> + constexpr auto __n = sizeof...(_Vs);
> + return iterator<false>(this, in_place_index<__n - 1>,
> + ranges::end(std::get<__n - 1>(_M_views)));
> + }
> + else
> + return default_sentinel;
> + }
> +
> + constexpr auto
> + end() const requires (range<const _Vs> && ...) && __detail::__concatable<const _Vs...>
> + {
> + if constexpr (__detail::__last_is_common<const _Vs...>::value)
> + {
> + constexpr auto __n = sizeof...(_Vs);
> + return iterator<true>(this, in_place_index<__n - 1>,
> + ranges::end(std::get<__n - 1>(_M_views)));
> + }
> + else
> + return default_sentinel;
> + }
> +
> + constexpr auto
> + size() requires (sized_range<_Vs>&&...)
> + {
> + return std::apply([](auto... __sizes) {
> + using _CT = __detail::__make_unsigned_like_t<common_type_t<decltype(__sizes)...>>;
> + return (_CT(__sizes) + ...);
> + }, __detail::__tuple_transform(ranges::size, _M_views));
> + }
> +
> + constexpr auto
> + size() const requires (sized_range<const _Vs>&&...)
> + {
> + return std::apply([](auto... __sizes) {
> + using _CT = __detail::__make_unsigned_like_t<common_type_t<decltype(__sizes)...>>;
> + return (_CT(__sizes) + ...);
> + }, __detail::__tuple_transform(ranges::size, _M_views));
> + }
> + };
> +
> + template <typename... _Rs>
> + concat_view(_Rs&&...) -> concat_view<views::all_t<_Rs>...>;
> +
> + namespace __detail
> + {
> + template<bool _Const, typename... _Vs>
> + struct __concat_view_iter_cat
> + { };
> +
> + template<bool _Const, typename... _Vs>
> + requires __detail::__all_forward<_Const, _Vs...>
> + struct __concat_view_iter_cat<_Const, _Vs...>
> + {
> + static auto
> + _S_iter_cat()
> + {
> + if constexpr (!is_reference_v<__concat_reference_t<__maybe_const_t<_Const, _Vs>...>>)
> + return input_iterator_tag{};
> + else
> + return []<typename... _Cats>(_Cats... __cats) {
> + if constexpr ((derived_from<_Cats, random_access_iterator_tag> && ...)
> + && __concat_is_random_access<_Const, _Vs...>)
> + return random_access_iterator_tag{};
> + else if constexpr ((derived_from<_Cats, bidirectional_iterator_tag> && ...)
> + && __concat_is_bidirectional<_Const, _Vs...>)
> + return bidirectional_iterator_tag{};
> + else if constexpr ((derived_from<_Cats, forward_iterator_tag> && ...))
> + return forward_iterator_tag{};
> + else
> + return input_iterator_tag{};
> + }(typename iterator_traits<iterator_t<__maybe_const_t<_Const, _Vs>>>
> + ::iterator_category{}...);
> + }
> + };
> + }
> +
> + template<input_range... _Vs>
> + requires (view<_Vs> && ...) && (sizeof...(_Vs) > 0) && __detail::__concatable<_Vs...>
> + template<bool _Const>
> + class concat_view<_Vs...>::iterator
> + : public __detail::__concat_view_iter_cat<_Const, _Vs...>
> + {
> + static auto
> + _S_iter_concept()
> + {
> + if constexpr (__detail::__concat_is_random_access<_Const, _Vs...>)
> + return random_access_iterator_tag{};
> + else if constexpr (__detail::__concat_is_bidirectional<_Const, _Vs...>)
> + return bidirectional_iterator_tag{};
> + else if constexpr (__detail::__all_forward<_Const, _Vs...>)
> + return forward_iterator_tag{};
> + else
> + return input_iterator_tag{};
> + }
> +
> + friend concat_view;
> + friend iterator<!_Const>;
> +
> + public:
> + // iterator_category defined in __concat_view_iter_cat
> + using iterator_concept = decltype(_S_iter_concept());
> + using value_type = __detail::__concat_value_t<__maybe_const_t<_Const, _Vs>...>;
> + using difference_type = common_type_t<range_difference_t<__maybe_const_t<_Const, _Vs>>...>;
> +
> + private:
> + using __base_iter = variant<iterator_t<__maybe_const_t<_Const, _Vs>>...>;
> +
> + __maybe_const_t<_Const, concat_view>* _M_parent = nullptr;
> + __base_iter _M_it;
> +
> + template<size_t _Nm>
> + constexpr void
> + _M_satisfy()
> + {
> + if constexpr (_Nm < (sizeof...(_Vs) - 1))
> + {
> + if (std::get<_Nm>(_M_it) == ranges::end(std::get<_Nm>(_M_parent->_M_views)))
> + {
> + _M_it.template emplace<_Nm + 1>(ranges::begin
> + (std::get<_Nm + 1>(_M_parent->_M_views)));
> + _M_satisfy<_Nm + 1>();
> + }
> + }
> + }
> +
> + template<size_t _Nm>
> + constexpr void
> + _M_prev()
> + {
> + if constexpr (_Nm == 0)
> + --std::get<0>(_M_it);
> + else
> + {
> + if (std::get<_Nm>(_M_it) == ranges::begin(std::get<_Nm>(_M_parent->_M_views)))
> + {
> + _M_it.template emplace<_Nm - 1>(ranges::end
> + (std::get<_Nm - 1>(_M_parent->_M_views)));
> + _M_prev<_Nm - 1>();
> + }
> + else
> + --std::get<_Nm>(_M_it);
> + }
> + }
> +
> + template<size_t _Nm>
> + constexpr void
> + _M_advance_fwd(difference_type __offset, difference_type __steps)
> + {
> + using _Dt = iter_difference_t<variant_alternative_t<_Nm, __base_iter>>;
> + if constexpr (_Nm == sizeof...(_Vs) - 1)
> + std::get<_Nm>(_M_it) += static_cast<_Dt>(__steps);
> + else
> + {
> + auto __n_size = ranges::distance(std::get<_Nm>(_M_parent->_M_views));
> + if (__offset + __steps < __n_size)
> + std::get<_Nm>(_M_it) += static_cast<_Dt>(__steps);
> + else
> + {
> + _M_it.template emplace<_Nm + 1>(ranges::begin
> + (std::get<_Nm + 1>(_M_parent->_M_views)));
> + _M_advance_fwd<_Nm + 1>(0, __offset + __steps - __n_size);
> + }
> + }
> + }
> +
> + template<size_t _Nm>
> + constexpr void
> + _M_advance_bwd(difference_type __offset, difference_type __steps)
> + {
> + using _Dt = iter_difference_t<variant_alternative_t<_Nm, __base_iter>>;
> + if constexpr (_Nm == 0)
> + std::get<_Nm>(_M_it) -= static_cast<_Dt>(__steps);
> + else {
> + if (__offset >= __steps)
> + std::get<_Nm>(_M_it) -= static_cast<_Dt>(__steps);
> + else
> + {
> + auto __prev_size = ranges::distance(std::get<_Nm - 1>(_M_parent->_M_views));
> + _M_it.template emplace<_Nm - 1>(ranges::end
> + (std::get<_Nm - 1>(_M_parent->_M_views)));
> + _M_advance_bwd<_Nm - 1>(__prev_size, __steps - __offset);
> + }
> + }
> + }
> +
> + // Invoke the function object __f, which has a call operator taking a size_t
> + // index template parameter (bounded by the number of underlying views),
> + // according the runtime value of __index.
> + template<typename _Fp>
> + static constexpr auto
> + _S_invoke_with_runtime_index(_Fp&& __f, size_t __index)
> + {
> + return [&__f, __index]<size_t _Idx>(this auto&& __self) {
> + if (_Idx == __index)
> + return __f.template operator()<_Idx>();
> + if constexpr (_Idx + 1 < sizeof...(_Vs))
> + return __self.template operator()<_Idx + 1>();
> + }.template operator()<0>();
> + }
> +
> + template<typename _Fp>
> + constexpr auto
> + _M_invoke_with_runtime_index(_Fp&& __f)
> + { return _S_invoke_with_runtime_index(std::forward<_Fp>(__f), _M_it.index()); }
> +
> + template<typename... _Args>
> + explicit constexpr
> + iterator(__maybe_const_t<_Const, concat_view>* __parent, _Args&&... __args)
> + requires constructible_from<__base_iter, _Args&&...>
> + : _M_parent(__parent), _M_it(std::forward<_Args>(__args)...)
> + { }
> +
> + public:
> + iterator() = default;
> +
> + constexpr
> + iterator(iterator<!_Const> __it)
> + requires _Const && (convertible_to<iterator_t<_Vs>, iterator_t<const _Vs>> && ...)
> + : _M_parent(__it._M_parent)
> + {
> + _M_invoke_with_runtime_index([this, &__it]<size_t _Idx>() {
> + _M_it.template emplace<_Idx>(std::get<_Idx>(std::move(__it._M_it)));
> + });
> + }
> +
> + constexpr decltype(auto)
> + operator*() const
> + {
> + __glibcxx_assert(!_M_it.valueless_by_exception());
> + using reference = __detail::__concat_reference_t<__maybe_const_t<_Const, _Vs>...>;
> + return std::visit([](auto&& __it) -> reference { return *__it; }, _M_it);
> + }
> +
> + constexpr iterator&
> + operator++()
> + {
> + _M_invoke_with_runtime_index([this]<size_t _Idx>() {
> + ++std::get<_Idx>(_M_it);
> + _M_satisfy<_Idx>();
> + });
> + return *this;
> + }
> +
> + constexpr void
> + operator++(int)
> + {
> + ++*this;
> + }
> +
> + constexpr iterator
> + operator++(int)
> + requires __detail::__all_forward<_Const, _Vs...>
> + {
> + auto __tmp = *this;
> + ++*this;
> + return __tmp;
> + }
> +
> + constexpr iterator&
> + operator--()
> + requires __detail::__concat_is_bidirectional<_Const, _Vs...>
> + {
> + __glibcxx_assert(!_M_it.valueless_by_exception());
> + _M_invoke_with_runtime_index([this]<size_t _Idx>() {
> + _M_prev<_Idx>();
> + });
> + return *this;
> + }
> +
> + constexpr iterator
> + operator--(int)
> + requires __detail::__concat_is_bidirectional<_Const, _Vs...>
> + {
> + auto __tmp = *this;
> + --*this;
> + return __tmp;
> + }
> +
> + constexpr iterator&
> + operator+=(difference_type __n)
> + requires __detail::__concat_is_random_access<_Const, _Vs...>
> + {
> + __glibcxx_assert(!_M_it.valueless_by_exception());
> + _M_invoke_with_runtime_index([this, __n]<size_t _Idx>() {
> + auto __begin = ranges::begin(std::get<_Idx>(_M_parent->_M_views));
> + if (__n > 0)
> + _M_advance_fwd<_Idx>(std::get<_Idx>(_M_it) - __begin, __n);
> + else if (__n < 0)
> + _M_advance_bwd<_Idx>(std::get<_Idx>(_M_it) - __begin, -__n);
> + });
> + return *this;
> + }
> +
> + constexpr iterator&
> + operator-=(difference_type __n)
> + requires __detail::__concat_is_random_access<_Const, _Vs...>
> + {
> + *this += -__n;
> + return *this;
> + }
> +
> + constexpr decltype(auto)
> + operator[](difference_type __n) const
> + requires __detail::__concat_is_random_access<_Const, _Vs...>
> + { return *((*this) + __n); }
> +
> + friend constexpr bool
> + operator==(const iterator& __x, const iterator& __y)
> + requires (equality_comparable<iterator_t<__maybe_const_t<_Const, _Vs>>> && ...)
> + {
> + __glibcxx_assert(!__x._M_it.valueless_by_exception());
> + __glibcxx_assert(!__y._M_it.valueless_by_exception());
> + return __x._M_it == __y._M_it;
> + }
> +
> + friend constexpr bool
> + operator==(const iterator& __it, default_sentinel_t)
> + {
> + __glibcxx_assert(!__it._M_it.valueless_by_exception());
> + constexpr auto __last_idx = sizeof...(_Vs) - 1;
> + return (__it._M_it.index() == __last_idx
> + && (std::get<__last_idx>(__it._M_it)
> + == ranges::end(std::get<__last_idx>(__it._M_parent->_M_views))));
> + }
> +
> + friend constexpr bool
> + operator<(const iterator& __x, const iterator& __y)
> + requires __detail::__all_random_access<_Const, _Vs...>
> + { return __x._M_it < __y._M_it; }
> +
> + friend constexpr bool
> + operator>(const iterator& __x, const iterator& __y)
> + requires __detail::__all_random_access<_Const, _Vs...>
> + { return __x._M_it > __y._M_it; }
> +
> + friend constexpr bool
> + operator<=(const iterator& __x, const iterator& __y)
> + requires __detail::__all_random_access<_Const, _Vs...>
> + { return __x._M_it <= __y._M_it; }
> +
> + friend constexpr bool
> + operator>=(const iterator& __x, const iterator& __y)
> + requires __detail::__all_random_access<_Const, _Vs...>
> + { return __x._M_it >= __y._M_it; }
> +
> + friend constexpr auto
> + operator<=>(const iterator& __x, const iterator& __y)
> + requires (__detail::__all_random_access<_Const, _Vs...>
> + && (three_way_comparable<iterator_t<__maybe_const_t<_Const, _Vs>>>
> + && ...))
> + { return __x._M_it <=> __y._M_it; }
> +
> + friend constexpr iterator
> + operator+(const iterator& __it, difference_type __n)
> + requires __detail::__concat_is_random_access<_Const, _Vs...>
> + { return auto(__it) += __n; }
> +
> + friend constexpr iterator
> + operator+(difference_type __n, const iterator& __it)
> + requires __detail::__concat_is_random_access<_Const, _Vs...>
> + { return __it + __n; }
> +
> + friend constexpr iterator
> + operator-(const iterator& __it, difference_type __n)
> + requires __detail::__concat_is_random_access<_Const, _Vs...>
> + { return auto(__it) -= __n; }
> +
> + friend constexpr difference_type
> + operator-(const iterator& __x, const iterator& __y)
> + requires __detail::__concat_is_random_access<_Const, _Vs...>
> + {
> + return _S_invoke_with_runtime_index([&]<size_t _Ix>() -> difference_type {
> + return _S_invoke_with_runtime_index([&]<size_t _Iy>() -> difference_type {
> + if constexpr (_Ix > _Iy)
> + {
> + auto __dy = ranges::distance(std::get<_Iy>(__y._M_it),
> + ranges::end(std::get<_Iy>(__y._M_parent
> + ->_M_views)));
> + auto __dx = ranges::distance(ranges::begin(std::get<_Ix>(__x._M_parent
> + ->_M_views)),
> + std::get<_Ix>(__x._M_it));
> + difference_type __sum = 0;
> + [&]<size_t _Idx = _Iy + 1>(this auto&& __self) {
> + if constexpr (_Idx < _Ix)
> + {
> + __sum += ranges::size(std::get<_Idx>(__x._M_parent->_M_views));
> + __self.template operator()<_Idx + 1>();
> + }
> + }();
> + return __dy + __sum + __dx;
> + }
> + else if constexpr (_Ix < _Iy)
> + return -(__y - __x);
> + else
> + return std::get<_Ix>(__x._M_it) - std::get<_Iy>(__y._M_it);
> + }, __y._M_it.index());
> + }, __x._M_it.index());
> + }
> +
> + friend constexpr difference_type
> + operator-(const iterator& __x, default_sentinel_t)
> + requires __detail::__concat_is_random_access<_Const, _Vs...>
> + && __detail::__last_is_common<__maybe_const_t<_Const, _Vs>...>::value
> + {
> + return _S_invoke_with_runtime_index([&]<size_t _Ix>() -> difference_type {
> + auto __dx = ranges::distance(std::get<_Ix>(__x._M_it),
> + ranges::end(std::get<_Ix>(__x._M_parent->_M_views)));
> + difference_type __sum = 0;
> + [&]<size_t _Idx = _Ix + 1>(this auto&& __self) {
> + if constexpr (_Idx < sizeof...(_Vs))
> + {
> + __sum += ranges::size(std::get<_Idx>(__x._M_parent->_M_views));
> + __self.template operator()<_Idx + 1>();
> + }
> + }();
> + return -(__dx + __sum);
> + }, __x._M_it.index());
> + }
> +
> + friend constexpr difference_type
> + operator-(default_sentinel_t, const iterator& __x)
> + requires __detail::__concat_is_random_access<_Const, _Vs...>
> + && __detail::__last_is_common<__maybe_const_t<_Const, _Vs>...>::value
> + { return -(__x - default_sentinel); }
> +
> + friend constexpr decltype(auto)
> + iter_move(const iterator& __it)
> + {
> + using _Res = __detail::__concat_rvalue_reference_t<__maybe_const_t<_Const, _Vs>...>;
> + return std::visit([](const auto& __i) -> _Res {
> + return ranges::iter_move(__i);
> + }, __it._M_it);
> + }
> +
> + friend constexpr void
> + iter_swap(const iterator& __x, const iterator& __y)
> + requires swappable_with<iter_reference_t<iterator>,
> + iter_reference_t<iterator>>
> + && (... && indirectly_swappable<iterator_t<__maybe_const_t<_Const, _Vs>>>)
> + {
> + std::visit([&](const auto& __it1, const auto& __it2) {
> + if constexpr (is_same_v<decltype(__it1), decltype(__it2)>)
> + ranges::iter_swap(__it1, __it2);
> + else
> + ranges::swap(*__it1, *__it2);
> + }, __x._M_it, __y._M_it);
> + }
> + };
> +
> + namespace views
> + {
> + namespace __detail
> + {
> + template<typename... _Ts>
> + concept __can_concat_view = requires { concat_view(std::declval<_Ts>()...); };
> + }
> +
> + struct _Concat
> + {
> + template<typename... _Ts>
> + requires __detail::__can_concat_view<_Ts...>
> + constexpr auto
> + operator() [[nodiscard]] (_Ts&&... __ts) const
> + {
> + if constexpr (sizeof...(_Ts) == 1)
> + return views::all(std::forward<_Ts>(__ts)...);
> + else
> + return concat_view(std::forward<_Ts>(__ts)...);
> + }
> + };
> +
> + inline constexpr _Concat concat;
> + }
> +
> +} // namespace ranges
> +#endif // __cpp_lib_ranges_concat
> +
> _GLIBCXX_END_NAMESPACE_VERSION
> } // namespace std
> #endif // library concepts
> diff --git a/libstdc++-v3/testsuite/std/ranges/concat/1.cc b/libstdc++-v3/testsuite/std/ranges/concat/1.cc
> new file mode 100644
> index 00000000000..91c8893cdc5
> --- /dev/null
> +++ b/libstdc++-v3/testsuite/std/ranges/concat/1.cc
> @@ -0,0 +1,61 @@
> +// { dg-do run { target c++26 } }
> +// { dg-add-options no_pch }
> +
> +#include <ranges>
> +
> +#if __cpp_lib_ranges_concat != 202403L
> +# error "Feature-test macro __cpp_lib_ranges_concat has wrong value in <ranges>"
> +#endif
> +
> +#include <algorithm>
> +#include <vector>
> +#include <array>
> +#include <utility>
> +#include <testsuite_hooks.h>
> +#include <testsuite_iterators.h>
> +
> +namespace ranges = std::ranges;
> +namespace views = std::views;
> +
> +constexpr bool
> +test01()
> +{
> + std::vector<int> v1{1, 2, 3}, v2{4, 5}, v3{};
> + std::array a{6, 7, 8};
> + auto s = views::single(9);
> +
> + auto v = views::concat(v1, v2, v3, a, s);
> + VERIFY( ranges::size(v) == 9 );
> + VERIFY( ranges::equal(v, views::iota(1, 10)) );
> + VERIFY( ranges::equal(v, views::iota(1, 10)) );
> + VERIFY( ranges::equal(v | views::reverse,
> + views::iota(1, 10) | views::reverse) );
> +
> + auto it0 = v.begin();
> + auto cit = std::as_const(v).begin();
> + VERIFY( it0 == it0 );
> + VERIFY( cit == cit );
> + VERIFY( it0 == cit );
> + VERIFY( it0 - it0 == 0);
> + for (int i = 0; i < 10; i++)
> + {
> + VERIFY( it0 + i - it0 == i);
> + VERIFY( it0 + i - i + i == it0 + i );
> + VERIFY( it0 + i - (it0 + i) == 0 );
> + }
> + VERIFY( std::default_sentinel - it0 == 9 );
> + VERIFY( it0 + 9 == std::default_sentinel );
> +
> + auto it5 = it0+5;
> + ranges::iter_swap(it0, it5);
> + VERIFY( *it0 == 6 && *it5 == 1 );
> + ranges::iter_swap(it0, it5);
> + *it0 = ranges::iter_move(it0);
> + return true;
> +}
> +
> +int
> +main()
> +{
> + static_assert(test01());
> +}
> --
> 2.45.0.rc0
>
next prev parent reply other threads:[~2024-04-29 9:11 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-22 21:42 Patrick Palka
2024-04-29 9:11 ` Jonathan Wakely [this message]
2024-05-23 22:05 ` Patrick Palka
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