diff options
Diffstat (limited to 'contrib/llvm-project/libcxx/include/__algorithm/iterator_operations.h')
| -rw-r--r-- | contrib/llvm-project/libcxx/include/__algorithm/iterator_operations.h | 83 |
1 files changed, 69 insertions, 14 deletions
diff --git a/contrib/llvm-project/libcxx/include/__algorithm/iterator_operations.h b/contrib/llvm-project/libcxx/include/__algorithm/iterator_operations.h index 8307d71214e5..af461878737f 100644 --- a/contrib/llvm-project/libcxx/include/__algorithm/iterator_operations.h +++ b/contrib/llvm-project/libcxx/include/__algorithm/iterator_operations.h @@ -10,13 +10,18 @@ #define _LIBCPP___ALGORITHM_ITERATOR_OPERATIONS_H #include <__algorithm/iter_swap.h> +#include <__algorithm/ranges_iterator_concept.h> #include <__config> #include <__iterator/advance.h> #include <__iterator/distance.h> +#include <__iterator/incrementable_traits.h> #include <__iterator/iter_move.h> #include <__iterator/iter_swap.h> #include <__iterator/iterator_traits.h> #include <__iterator/next.h> +#include <__iterator/prev.h> +#include <__iterator/readable_traits.h> +#include <__utility/declval.h> #include <__utility/forward.h> #include <__utility/move.h> #include <type_traits> @@ -34,11 +39,22 @@ struct _RangeAlgPolicy {}; template <> struct _IterOps<_RangeAlgPolicy> { + + template <class _Iter> + using __value_type = iter_value_t<_Iter>; + + template <class _Iter> + using __iterator_category = ranges::__iterator_concept<_Iter>; + + template <class _Iter> + using __difference_type = iter_difference_t<_Iter>; + static constexpr auto advance = ranges::advance; static constexpr auto distance = ranges::distance; static constexpr auto __iter_move = ranges::iter_move; static constexpr auto iter_swap = ranges::iter_swap; static constexpr auto next = ranges::next; + static constexpr auto prev = ranges::prev; static constexpr auto __advance_to = ranges::advance; }; @@ -49,6 +65,15 @@ struct _ClassicAlgPolicy {}; template <> struct _IterOps<_ClassicAlgPolicy> { + template <class _Iter> + using __value_type = typename iterator_traits<_Iter>::value_type; + + template <class _Iter> + using __iterator_category = typename iterator_traits<_Iter>::iterator_category; + + template <class _Iter> + using __difference_type = typename iterator_traits<_Iter>::difference_type; + // advance template <class _Iter, class _Distance> _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11 @@ -63,24 +88,46 @@ struct _IterOps<_ClassicAlgPolicy> { return std::distance(__first, __last); } - // iter_move + template <class _Iter> + using __deref_t = decltype(*std::declval<_Iter&>()); + + template <class _Iter> + using __move_t = decltype(std::move(*std::declval<_Iter&>())); + template <class _Iter> _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11 - // Declaring the return type is necessary for C++03, so we basically mirror what `decltype(auto)` would deduce. - static __enable_if_t< - is_reference<typename iterator_traits<__uncvref_t<_Iter> >::reference>::value, - typename remove_reference< typename iterator_traits<__uncvref_t<_Iter> >::reference >::type&&> - __iter_move(_Iter&& __i) { + static void __validate_iter_reference() { + static_assert(is_same<__deref_t<_Iter>, typename iterator_traits<__uncvref_t<_Iter> >::reference>::value, + "It looks like your iterator's `iterator_traits<It>::reference` does not match the return type of " + "dereferencing the iterator, i.e., calling `*it`. This is undefined behavior according to [input.iterators] " + "and can lead to dangling reference issues at runtime, so we are flagging this."); + } + + // iter_move + template <class _Iter> + _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11 static + // If the result of dereferencing `_Iter` is a reference type, deduce the result of calling `std::move` on it. Note + // that the C++03 mode doesn't support `decltype(auto)` as the return type. + __enable_if_t< + is_reference<__deref_t<_Iter> >::value, + __move_t<_Iter> > + __iter_move(_Iter&& __i) { + __validate_iter_reference<_Iter>(); + return std::move(*std::forward<_Iter>(__i)); } template <class _Iter> - _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11 - // Declaring the return type is necessary for C++03, so we basically mirror what `decltype(auto)` would deduce. - static __enable_if_t< - !is_reference<typename iterator_traits<__uncvref_t<_Iter> >::reference>::value, - typename iterator_traits<__uncvref_t<_Iter> >::reference> - __iter_move(_Iter&& __i) { + _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX11 static + // If the result of dereferencing `_Iter` is a value type, deduce the return value of this function to also be a + // value -- otherwise, after `operator*` returns a temporary, this function would return a dangling reference to that + // temporary. Note that the C++03 mode doesn't support `auto` as the return type. + __enable_if_t< + !is_reference<__deref_t<_Iter> >::value, + __deref_t<_Iter> > + __iter_move(_Iter&& __i) { + __validate_iter_reference<_Iter>(); + return *std::forward<_Iter>(__i); } @@ -100,11 +147,19 @@ struct _IterOps<_ClassicAlgPolicy> { template <class _Iter> _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR_AFTER_CXX11 - __uncvref_t<_Iter> next(_Iter&& __it, - typename iterator_traits<__uncvref_t<_Iter> >::difference_type __n = 1){ + __uncvref_t<_Iter> next(_Iter&& __it, + typename iterator_traits<__uncvref_t<_Iter> >::difference_type __n = 1) { return std::next(std::forward<_Iter>(__it), __n); } + // prev + template <class _Iter> + _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR_AFTER_CXX11 + __uncvref_t<_Iter> prev(_Iter&& __iter, + typename iterator_traits<__uncvref_t<_Iter> >::difference_type __n = 1) { + return std::prev(std::forward<_Iter>(__iter), __n); + } + template <class _Iter> _LIBCPP_HIDE_FROM_ABI static _LIBCPP_CONSTEXPR_AFTER_CXX11 void __advance_to(_Iter& __first, _Iter __last) { |