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fb3477a4da
Simplify the implementation of `std::copy` and `std::move` by using `__unwrap_iter` and `__rewrap_iter` to unwrap and rewrap `reverse_iterator<reverse_iterator<Iter>>` instead of specializing `__copy_impl` and `__move_impl`. Reviewed By: ldionne, #libc Spies: wenlei, libcxx-commits Differential Revision: https://reviews.llvm.org/D127049
371 lines
14 KiB
C++
371 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___ITERATOR_REVERSE_ITERATOR_H
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#define _LIBCPP___ITERATOR_REVERSE_ITERATOR_H
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#include <__algorithm/unwrap_iter.h>
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#include <__compare/compare_three_way_result.h>
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#include <__compare/three_way_comparable.h>
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#include <__concepts/convertible_to.h>
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#include <__config>
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#include <__iterator/concepts.h>
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#include <__iterator/incrementable_traits.h>
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#include <__iterator/iter_move.h>
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#include <__iterator/iter_swap.h>
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#include <__iterator/iterator.h>
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#include <__iterator/iterator_traits.h>
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#include <__iterator/prev.h>
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#include <__iterator/readable_traits.h>
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#include <__memory/addressof.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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_LIBCPP_SUPPRESS_DEPRECATED_PUSH
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template <class _Iter>
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class _LIBCPP_TEMPLATE_VIS reverse_iterator
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#if _LIBCPP_STD_VER <= 14 || !defined(_LIBCPP_ABI_NO_ITERATOR_BASES)
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: public iterator<typename iterator_traits<_Iter>::iterator_category,
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typename iterator_traits<_Iter>::value_type,
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typename iterator_traits<_Iter>::difference_type,
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typename iterator_traits<_Iter>::pointer,
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typename iterator_traits<_Iter>::reference>
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#endif
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{
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_LIBCPP_SUPPRESS_DEPRECATED_POP
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private:
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#ifndef _LIBCPP_ABI_NO_ITERATOR_BASES
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_Iter __t; // no longer used as of LWG #2360, not removed due to ABI break
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#endif
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#if _LIBCPP_STD_VER > 17
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static_assert(__is_cpp17_bidirectional_iterator<_Iter>::value || bidirectional_iterator<_Iter>,
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"reverse_iterator<It> requires It to be a bidirectional iterator.");
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#endif // _LIBCPP_STD_VER > 17
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protected:
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_Iter current;
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public:
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using iterator_type = _Iter;
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using iterator_category = _If<__is_cpp17_random_access_iterator<_Iter>::value,
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random_access_iterator_tag,
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typename iterator_traits<_Iter>::iterator_category>;
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using pointer = typename iterator_traits<_Iter>::pointer;
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#if _LIBCPP_STD_VER > 17
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using iterator_concept = _If<__is_cpp17_random_access_iterator<_Iter>::value,
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random_access_iterator_tag,
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bidirectional_iterator_tag>;
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using value_type = iter_value_t<_Iter>;
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using difference_type = iter_difference_t<_Iter>;
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using reference = iter_reference_t<_Iter>;
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#else
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using value_type = typename iterator_traits<_Iter>::value_type;
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using difference_type = typename iterator_traits<_Iter>::difference_type;
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using reference = typename iterator_traits<_Iter>::reference;
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#endif
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#ifndef _LIBCPP_ABI_NO_ITERATOR_BASES
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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reverse_iterator() : __t(), current() {}
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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explicit reverse_iterator(_Iter __x) : __t(__x), current(__x) {}
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template <class _Up, class = __enable_if_t<
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!is_same<_Up, _Iter>::value && is_convertible<_Up const&, _Iter>::value
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> >
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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reverse_iterator(const reverse_iterator<_Up>& __u)
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: __t(__u.base()), current(__u.base())
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{ }
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template <class _Up, class = __enable_if_t<
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!is_same<_Up, _Iter>::value &&
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is_convertible<_Up const&, _Iter>::value &&
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is_assignable<_Iter&, _Up const&>::value
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> >
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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reverse_iterator& operator=(const reverse_iterator<_Up>& __u) {
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__t = current = __u.base();
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return *this;
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}
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#else
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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reverse_iterator() : current() {}
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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explicit reverse_iterator(_Iter __x) : current(__x) {}
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template <class _Up, class = __enable_if_t<
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!is_same<_Up, _Iter>::value && is_convertible<_Up const&, _Iter>::value
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> >
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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reverse_iterator(const reverse_iterator<_Up>& __u)
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: current(__u.base())
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{ }
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template <class _Up, class = __enable_if_t<
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!is_same<_Up, _Iter>::value &&
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is_convertible<_Up const&, _Iter>::value &&
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is_assignable<_Iter&, _Up const&>::value
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> >
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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reverse_iterator& operator=(const reverse_iterator<_Up>& __u) {
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current = __u.base();
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return *this;
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}
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#endif
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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_Iter base() const {return current;}
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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reference operator*() const {_Iter __tmp = current; return *--__tmp;}
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#if _LIBCPP_STD_VER > 17
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_LIBCPP_INLINE_VISIBILITY
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constexpr pointer operator->() const
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requires is_pointer_v<_Iter> || requires(const _Iter i) { i.operator->(); }
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{
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if constexpr (is_pointer_v<_Iter>) {
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return std::prev(current);
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} else {
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return std::prev(current).operator->();
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}
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}
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#else
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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pointer operator->() const {
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return std::addressof(operator*());
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}
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#endif // _LIBCPP_STD_VER > 17
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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reverse_iterator& operator++() {--current; return *this;}
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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reverse_iterator operator++(int) {reverse_iterator __tmp(*this); --current; return __tmp;}
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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reverse_iterator& operator--() {++current; return *this;}
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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reverse_iterator operator--(int) {reverse_iterator __tmp(*this); ++current; return __tmp;}
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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reverse_iterator operator+(difference_type __n) const {return reverse_iterator(current - __n);}
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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reverse_iterator& operator+=(difference_type __n) {current -= __n; return *this;}
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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reverse_iterator operator-(difference_type __n) const {return reverse_iterator(current + __n);}
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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reverse_iterator& operator-=(difference_type __n) {current += __n; return *this;}
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_LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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reference operator[](difference_type __n) const {return *(*this + __n);}
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#if _LIBCPP_STD_VER > 17
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_LIBCPP_HIDE_FROM_ABI friend constexpr
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iter_rvalue_reference_t<_Iter> iter_move(const reverse_iterator& __i)
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noexcept(is_nothrow_copy_constructible_v<_Iter> &&
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noexcept(ranges::iter_move(--declval<_Iter&>()))) {
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auto __tmp = __i.base();
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return ranges::iter_move(--__tmp);
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}
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template <indirectly_swappable<_Iter> _Iter2>
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_LIBCPP_HIDE_FROM_ABI friend constexpr
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void iter_swap(const reverse_iterator& __x, const reverse_iterator<_Iter2>& __y)
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noexcept(is_nothrow_copy_constructible_v<_Iter> &&
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is_nothrow_copy_constructible_v<_Iter2> &&
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noexcept(ranges::iter_swap(--declval<_Iter&>(), --declval<_Iter2&>()))) {
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auto __xtmp = __x.base();
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auto __ytmp = __y.base();
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ranges::iter_swap(--__xtmp, --__ytmp);
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}
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#endif // _LIBCPP_STD_VER > 17
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};
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template <class _Iter1, class _Iter2>
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inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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bool
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operator==(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
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#if _LIBCPP_STD_VER > 17
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requires requires {
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{ __x.base() == __y.base() } -> convertible_to<bool>;
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}
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#endif // _LIBCPP_STD_VER > 17
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{
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return __x.base() == __y.base();
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}
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template <class _Iter1, class _Iter2>
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inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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bool
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operator<(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
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#if _LIBCPP_STD_VER > 17
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requires requires {
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{ __x.base() > __y.base() } -> convertible_to<bool>;
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}
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#endif // _LIBCPP_STD_VER > 17
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{
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return __x.base() > __y.base();
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}
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template <class _Iter1, class _Iter2>
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inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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bool
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operator!=(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
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#if _LIBCPP_STD_VER > 17
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requires requires {
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{ __x.base() != __y.base() } -> convertible_to<bool>;
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}
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#endif // _LIBCPP_STD_VER > 17
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{
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return __x.base() != __y.base();
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}
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template <class _Iter1, class _Iter2>
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inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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bool
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operator>(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
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#if _LIBCPP_STD_VER > 17
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requires requires {
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{ __x.base() < __y.base() } -> convertible_to<bool>;
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}
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#endif // _LIBCPP_STD_VER > 17
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{
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return __x.base() < __y.base();
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}
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template <class _Iter1, class _Iter2>
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inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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bool
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operator>=(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
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#if _LIBCPP_STD_VER > 17
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requires requires {
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{ __x.base() <= __y.base() } -> convertible_to<bool>;
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}
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#endif // _LIBCPP_STD_VER > 17
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{
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return __x.base() <= __y.base();
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}
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template <class _Iter1, class _Iter2>
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inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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bool
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operator<=(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
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#if _LIBCPP_STD_VER > 17
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requires requires {
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{ __x.base() >= __y.base() } -> convertible_to<bool>;
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}
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#endif // _LIBCPP_STD_VER > 17
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{
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return __x.base() >= __y.base();
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}
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#if _LIBCPP_STD_VER > 17
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template <class _Iter1, three_way_comparable_with<_Iter1> _Iter2>
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_LIBCPP_HIDE_FROM_ABI constexpr
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compare_three_way_result_t<_Iter1, _Iter2>
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operator<=>(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
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{
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return __y.base() <=> __x.base();
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}
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#endif // _LIBCPP_STD_VER > 17
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#ifndef _LIBCPP_CXX03_LANG
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template <class _Iter1, class _Iter2>
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inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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auto
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operator-(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
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-> decltype(__y.base() - __x.base())
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{
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return __y.base() - __x.base();
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}
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#else
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template <class _Iter1, class _Iter2>
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inline _LIBCPP_INLINE_VISIBILITY
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typename reverse_iterator<_Iter1>::difference_type
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operator-(const reverse_iterator<_Iter1>& __x, const reverse_iterator<_Iter2>& __y)
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{
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return __y.base() - __x.base();
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}
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#endif
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template <class _Iter>
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inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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reverse_iterator<_Iter>
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operator+(typename reverse_iterator<_Iter>::difference_type __n, const reverse_iterator<_Iter>& __x)
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{
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return reverse_iterator<_Iter>(__x.base() - __n);
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}
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#if _LIBCPP_STD_VER > 17
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template <class _Iter1, class _Iter2>
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requires (!sized_sentinel_for<_Iter1, _Iter2>)
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inline constexpr bool disable_sized_sentinel_for<reverse_iterator<_Iter1>, reverse_iterator<_Iter2>> = true;
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#endif // _LIBCPP_STD_VER > 17
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#if _LIBCPP_STD_VER > 11
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template <class _Iter>
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inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX14
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reverse_iterator<_Iter> make_reverse_iterator(_Iter __i)
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{
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return reverse_iterator<_Iter>(__i);
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}
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#endif
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template <class _Iter>
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using _ReverseWrapper = reverse_iterator<reverse_iterator<_Iter> >;
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template <class _Iter, bool __b>
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struct __unwrap_iter_impl<_ReverseWrapper<_Iter>, __b> {
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static _LIBCPP_CONSTEXPR decltype(std::__unwrap_iter(std::declval<_Iter>()))
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__apply(_ReverseWrapper<_Iter> __i) _NOEXCEPT {
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return std::__unwrap_iter(__i.base().base());
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}
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};
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template <class _OrigIter, class _UnwrappedIter>
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struct __rewrap_iter_impl<_ReverseWrapper<_OrigIter>, _UnwrappedIter> {
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template <class _Iter>
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struct _ReverseWrapperCount {
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static _LIBCPP_CONSTEXPR const size_t value = 1;
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};
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template <class _Iter>
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struct _ReverseWrapperCount<_ReverseWrapper<_Iter> > {
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static _LIBCPP_CONSTEXPR const size_t value = 1 + _ReverseWrapperCount<_Iter>::value;
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};
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template <size_t _RewrapCount, class _OIter, class _UIter, __enable_if_t<_RewrapCount != 0, int> = 0>
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_LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR _ReverseWrapper<_OIter> __rewrap(_ReverseWrapper<_OIter> __iter1,
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_UIter __iter2) {
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return _ReverseWrapper<_OIter>(
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reverse_iterator<_OIter>(__rewrap<_RewrapCount - 1>(__iter1.base().base(), __iter2)));
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}
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template <size_t _RewrapCount, class _OIter, class _UIter, __enable_if_t<_RewrapCount == 0, int> = 0>
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_LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR decltype(std::__rewrap_iter(std::declval<_OIter>(),
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std::declval<_UIter>()))
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__rewrap(_OIter __iter1, _UIter __iter2) {
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return std::__rewrap_iter(__iter1, __iter2);
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}
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_LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR _ReverseWrapper<_OrigIter> __apply(_ReverseWrapper<_OrigIter> __iter1,
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_UnwrappedIter __iter2) {
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return __rewrap<_ReverseWrapperCount<_OrigIter>::value>(__iter1, __iter2);
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}
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};
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_LIBCPP_END_NAMESPACE_STD
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#endif // _LIBCPP___ITERATOR_REVERSE_ITERATOR_H
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