441 lines
14 KiB
C++
441 lines
14 KiB
C++
// -*- C++ -*-
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//===----------------------------------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _LIBCPP___RANGES_TRANSFORM_VIEW_H
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#define _LIBCPP___RANGES_TRANSFORM_VIEW_H
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#include <__compare/three_way_comparable.h>
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#include <__concepts/constructible.h>
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#include <__concepts/convertible_to.h>
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#include <__concepts/copyable.h>
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#include <__concepts/derived_from.h>
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#include <__concepts/equality_comparable.h>
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#include <__concepts/invocable.h>
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#include <__config>
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#include <__functional/bind_back.h>
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#include <__functional/invoke.h>
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#include <__iterator/concepts.h>
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#include <__iterator/iterator_traits.h>
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#include <__memory/addressof.h>
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#include <__ranges/access.h>
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#include <__ranges/all.h>
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#include <__ranges/concepts.h>
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#include <__ranges/copyable_box.h>
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#include <__ranges/empty.h>
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#include <__ranges/range_adaptor.h>
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#include <__ranges/size.h>
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#include <__ranges/view_interface.h>
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#include <__utility/forward.h>
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#include <__utility/in_place.h>
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#include <__utility/move.h>
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#include <type_traits>
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#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
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# pragma GCC system_header
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#endif
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_LIBCPP_BEGIN_NAMESPACE_STD
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#if !defined(_LIBCPP_HAS_NO_CONCEPTS) && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
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namespace ranges {
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template<class _Fn, class _View>
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concept __regular_invocable_with_range_ref =
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regular_invocable<_Fn, range_reference_t<_View>>;
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template<class _View, class _Fn>
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concept __transform_view_constraints =
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view<_View> && is_object_v<_Fn> &&
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regular_invocable<_Fn&, range_reference_t<_View>> &&
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__can_reference<invoke_result_t<_Fn&, range_reference_t<_View>>>;
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template<input_range _View, copy_constructible _Fn>
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requires __transform_view_constraints<_View, _Fn>
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class transform_view : public view_interface<transform_view<_View, _Fn>> {
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template<bool> class __iterator;
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template<bool> class __sentinel;
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_LIBCPP_NO_UNIQUE_ADDRESS __copyable_box<_Fn> __func_;
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_LIBCPP_NO_UNIQUE_ADDRESS _View __base_ = _View();
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public:
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_LIBCPP_HIDE_FROM_ABI
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transform_view()
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requires default_initializable<_View> && default_initializable<_Fn> = default;
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_LIBCPP_HIDE_FROM_ABI
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constexpr transform_view(_View __base, _Fn __func)
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: __func_(std::in_place, std::move(__func)), __base_(std::move(__base)) {}
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_LIBCPP_HIDE_FROM_ABI
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constexpr _View base() const& requires copy_constructible<_View> { return __base_; }
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_LIBCPP_HIDE_FROM_ABI
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constexpr _View base() && { return std::move(__base_); }
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_LIBCPP_HIDE_FROM_ABI
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constexpr __iterator<false> begin() {
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return __iterator<false>{*this, ranges::begin(__base_)};
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}
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_LIBCPP_HIDE_FROM_ABI
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constexpr __iterator<true> begin() const
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requires range<const _View> &&
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__regular_invocable_with_range_ref<const _Fn&, const _View>
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{
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return __iterator<true>(*this, ranges::begin(__base_));
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}
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_LIBCPP_HIDE_FROM_ABI
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constexpr __sentinel<false> end() {
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return __sentinel<false>(ranges::end(__base_));
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}
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_LIBCPP_HIDE_FROM_ABI
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constexpr __iterator<false> end()
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requires common_range<_View>
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{
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return __iterator<false>(*this, ranges::end(__base_));
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}
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_LIBCPP_HIDE_FROM_ABI
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constexpr __sentinel<true> end() const
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requires range<const _View> &&
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__regular_invocable_with_range_ref<const _Fn&, const _View>
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{
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return __sentinel<true>(ranges::end(__base_));
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}
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_LIBCPP_HIDE_FROM_ABI
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constexpr __iterator<true> end() const
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requires common_range<const _View> &&
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__regular_invocable_with_range_ref<const _Fn&, const _View>
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{
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return __iterator<true>(*this, ranges::end(__base_));
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}
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_LIBCPP_HIDE_FROM_ABI
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constexpr auto size() requires sized_range<_View> { return ranges::size(__base_); }
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_LIBCPP_HIDE_FROM_ABI
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constexpr auto size() const requires sized_range<const _View> { return ranges::size(__base_); }
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};
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template<class _Range, class _Fn>
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transform_view(_Range&&, _Fn) -> transform_view<views::all_t<_Range>, _Fn>;
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template<class _View>
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struct __transform_view_iterator_concept { using type = input_iterator_tag; };
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template<random_access_range _View>
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struct __transform_view_iterator_concept<_View> { using type = random_access_iterator_tag; };
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template<bidirectional_range _View>
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struct __transform_view_iterator_concept<_View> { using type = bidirectional_iterator_tag; };
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template<forward_range _View>
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struct __transform_view_iterator_concept<_View> { using type = forward_iterator_tag; };
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template<class, class>
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struct __transform_view_iterator_category_base {};
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template<forward_range _View, class _Fn>
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struct __transform_view_iterator_category_base<_View, _Fn> {
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using _Cat = typename iterator_traits<iterator_t<_View>>::iterator_category;
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using iterator_category = conditional_t<
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is_lvalue_reference_v<invoke_result_t<_Fn&, range_reference_t<_View>>>,
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conditional_t<
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derived_from<_Cat, contiguous_iterator_tag>,
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random_access_iterator_tag,
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_Cat
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>,
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input_iterator_tag
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>;
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};
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template<input_range _View, copy_constructible _Fn>
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requires __transform_view_constraints<_View, _Fn>
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template<bool _Const>
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class transform_view<_View, _Fn>::__iterator
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: public __transform_view_iterator_category_base<_View, _Fn> {
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using _Parent = __maybe_const<_Const, transform_view>;
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using _Base = __maybe_const<_Const, _View>;
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_Parent *__parent_ = nullptr;
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template<bool>
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friend class transform_view<_View, _Fn>::__iterator;
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template<bool>
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friend class transform_view<_View, _Fn>::__sentinel;
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public:
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iterator_t<_Base> __current_ = iterator_t<_Base>();
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using iterator_concept = typename __transform_view_iterator_concept<_View>::type;
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using value_type = remove_cvref_t<invoke_result_t<_Fn&, range_reference_t<_Base>>>;
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using difference_type = range_difference_t<_Base>;
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_LIBCPP_HIDE_FROM_ABI
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__iterator() requires default_initializable<iterator_t<_Base>> = default;
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_LIBCPP_HIDE_FROM_ABI
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constexpr __iterator(_Parent& __parent, iterator_t<_Base> __current)
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: __parent_(std::addressof(__parent)), __current_(std::move(__current)) {}
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// Note: `__i` should always be `__iterator<false>`, but directly using
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// `__iterator<false>` is ill-formed when `_Const` is false
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// (see http://wg21.link/class.copy.ctor#5).
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_LIBCPP_HIDE_FROM_ABI
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constexpr __iterator(__iterator<!_Const> __i)
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requires _Const && convertible_to<iterator_t<_View>, iterator_t<_Base>>
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: __parent_(__i.__parent_), __current_(std::move(__i.__current_)) {}
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_LIBCPP_HIDE_FROM_ABI
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constexpr const iterator_t<_Base>& base() const& noexcept {
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return __current_;
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}
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_LIBCPP_HIDE_FROM_ABI
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constexpr iterator_t<_Base> base() && {
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return std::move(__current_);
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}
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_LIBCPP_HIDE_FROM_ABI
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constexpr decltype(auto) operator*() const
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noexcept(noexcept(std::invoke(*__parent_->__func_, *__current_)))
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{
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return std::invoke(*__parent_->__func_, *__current_);
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}
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_LIBCPP_HIDE_FROM_ABI
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constexpr __iterator& operator++() {
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++__current_;
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return *this;
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}
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_LIBCPP_HIDE_FROM_ABI
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constexpr void operator++(int) { ++__current_; }
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_LIBCPP_HIDE_FROM_ABI
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constexpr __iterator operator++(int)
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requires forward_range<_Base>
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{
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auto __tmp = *this;
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++*this;
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return __tmp;
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}
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_LIBCPP_HIDE_FROM_ABI
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constexpr __iterator& operator--()
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requires bidirectional_range<_Base>
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{
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--__current_;
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return *this;
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}
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_LIBCPP_HIDE_FROM_ABI
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constexpr __iterator operator--(int)
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requires bidirectional_range<_Base>
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{
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auto __tmp = *this;
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--*this;
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return __tmp;
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}
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_LIBCPP_HIDE_FROM_ABI
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constexpr __iterator& operator+=(difference_type __n)
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requires random_access_range<_Base>
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{
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__current_ += __n;
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return *this;
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}
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_LIBCPP_HIDE_FROM_ABI
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constexpr __iterator& operator-=(difference_type __n)
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requires random_access_range<_Base>
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{
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__current_ -= __n;
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return *this;
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}
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_LIBCPP_HIDE_FROM_ABI
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constexpr decltype(auto) operator[](difference_type __n) const
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noexcept(noexcept(std::invoke(*__parent_->__func_, __current_[__n])))
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requires random_access_range<_Base>
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{
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return std::invoke(*__parent_->__func_, __current_[__n]);
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}
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_LIBCPP_HIDE_FROM_ABI
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friend constexpr bool operator==(const __iterator& __x, const __iterator& __y)
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requires equality_comparable<iterator_t<_Base>>
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{
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return __x.__current_ == __y.__current_;
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}
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_LIBCPP_HIDE_FROM_ABI
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friend constexpr bool operator<(const __iterator& __x, const __iterator& __y)
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requires random_access_range<_Base>
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{
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return __x.__current_ < __y.__current_;
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}
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_LIBCPP_HIDE_FROM_ABI
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friend constexpr bool operator>(const __iterator& __x, const __iterator& __y)
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requires random_access_range<_Base>
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{
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return __x.__current_ > __y.__current_;
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}
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_LIBCPP_HIDE_FROM_ABI
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friend constexpr bool operator<=(const __iterator& __x, const __iterator& __y)
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requires random_access_range<_Base>
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{
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return __x.__current_ <= __y.__current_;
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}
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_LIBCPP_HIDE_FROM_ABI
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friend constexpr bool operator>=(const __iterator& __x, const __iterator& __y)
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requires random_access_range<_Base>
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{
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return __x.__current_ >= __y.__current_;
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}
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_LIBCPP_HIDE_FROM_ABI
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friend constexpr auto operator<=>(const __iterator& __x, const __iterator& __y)
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requires random_access_range<_Base> && three_way_comparable<iterator_t<_Base>>
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{
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return __x.__current_ <=> __y.__current_;
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}
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_LIBCPP_HIDE_FROM_ABI
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friend constexpr __iterator operator+(__iterator __i, difference_type __n)
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requires random_access_range<_Base>
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{
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return __iterator{*__i.__parent_, __i.__current_ + __n};
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}
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_LIBCPP_HIDE_FROM_ABI
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friend constexpr __iterator operator+(difference_type __n, __iterator __i)
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requires random_access_range<_Base>
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{
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return __iterator{*__i.__parent_, __i.__current_ + __n};
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}
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_LIBCPP_HIDE_FROM_ABI
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friend constexpr __iterator operator-(__iterator __i, difference_type __n)
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requires random_access_range<_Base>
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{
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return __iterator{*__i.__parent_, __i.__current_ - __n};
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}
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_LIBCPP_HIDE_FROM_ABI
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friend constexpr difference_type operator-(const __iterator& __x, const __iterator& __y)
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requires sized_sentinel_for<iterator_t<_Base>, iterator_t<_Base>>
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{
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return __x.__current_ - __y.__current_;
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}
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_LIBCPP_HIDE_FROM_ABI
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friend constexpr decltype(auto) iter_move(const __iterator& __i)
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noexcept(noexcept(*__i))
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{
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if constexpr (is_lvalue_reference_v<decltype(*__i)>)
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return std::move(*__i);
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else
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return *__i;
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}
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};
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template<input_range _View, copy_constructible _Fn>
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requires __transform_view_constraints<_View, _Fn>
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template<bool _Const>
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class transform_view<_View, _Fn>::__sentinel {
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using _Parent = __maybe_const<_Const, transform_view>;
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using _Base = __maybe_const<_Const, _View>;
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sentinel_t<_Base> __end_ = sentinel_t<_Base>();
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template<bool>
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friend class transform_view<_View, _Fn>::__iterator;
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template<bool>
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friend class transform_view<_View, _Fn>::__sentinel;
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public:
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_LIBCPP_HIDE_FROM_ABI
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__sentinel() = default;
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_LIBCPP_HIDE_FROM_ABI
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constexpr explicit __sentinel(sentinel_t<_Base> __end) : __end_(__end) {}
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// Note: `__i` should always be `__sentinel<false>`, but directly using
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// `__sentinel<false>` is ill-formed when `_Const` is false
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// (see http://wg21.link/class.copy.ctor#5).
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_LIBCPP_HIDE_FROM_ABI
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constexpr __sentinel(__sentinel<!_Const> __i)
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requires _Const && convertible_to<sentinel_t<_View>, sentinel_t<_Base>>
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: __end_(std::move(__i.__end_)) {}
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_LIBCPP_HIDE_FROM_ABI
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constexpr sentinel_t<_Base> base() const { return __end_; }
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template<bool _OtherConst>
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requires sentinel_for<sentinel_t<_Base>, iterator_t<__maybe_const<_OtherConst, _View>>>
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_LIBCPP_HIDE_FROM_ABI
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friend constexpr bool operator==(const __iterator<_OtherConst>& __x, const __sentinel& __y) {
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return __x.__current_ == __y.__end_;
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}
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template<bool _OtherConst>
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requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<__maybe_const<_OtherConst, _View>>>
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_LIBCPP_HIDE_FROM_ABI
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friend constexpr range_difference_t<__maybe_const<_OtherConst, _View>>
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operator-(const __iterator<_OtherConst>& __x, const __sentinel& __y) {
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return __x.__current_ - __y.__end_;
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}
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template<bool _OtherConst>
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requires sized_sentinel_for<sentinel_t<_Base>, iterator_t<__maybe_const<_OtherConst, _View>>>
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_LIBCPP_HIDE_FROM_ABI
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friend constexpr range_difference_t<__maybe_const<_OtherConst, _View>>
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operator-(const __sentinel& __x, const __iterator<_OtherConst>& __y) {
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return __x.__end_ - __y.__current_;
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}
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};
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namespace views {
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namespace __transform {
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struct __fn {
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template<class _Range, class _Fn>
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[[nodiscard]] _LIBCPP_HIDE_FROM_ABI
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constexpr auto operator()(_Range&& __range, _Fn&& __f) const
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noexcept(noexcept(transform_view(std::forward<_Range>(__range), std::forward<_Fn>(__f))))
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-> decltype( transform_view(std::forward<_Range>(__range), std::forward<_Fn>(__f)))
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{ return transform_view(std::forward<_Range>(__range), std::forward<_Fn>(__f)); }
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template<class _Fn>
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requires constructible_from<decay_t<_Fn>, _Fn>
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[[nodiscard]] _LIBCPP_HIDE_FROM_ABI
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constexpr auto operator()(_Fn&& __f) const
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noexcept(is_nothrow_constructible_v<decay_t<_Fn>, _Fn>)
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{ return __range_adaptor_closure_t(std::__bind_back(*this, std::forward<_Fn>(__f))); }
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};
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} // namespace __transform
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inline namespace __cpo {
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inline constexpr auto transform = __transform::__fn{};
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} // namespace __cpo
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} // namespace views
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} // namespace ranges
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#endif // !defined(_LIBCPP_HAS_NO_CONCEPTS) && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP___RANGES_TRANSFORM_VIEW_H
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