diff options
Diffstat (limited to 'libcxx')
| -rw-r--r-- | libcxx/docs/ReleaseNotes/22.rst | 5 | ||||
| -rw-r--r-- | libcxx/include/__algorithm/generate_n.h | 16 | ||||
| -rw-r--r-- | libcxx/include/__algorithm/ranges_generate_n.h | 8 |
3 files changed, 19 insertions, 10 deletions
diff --git a/libcxx/docs/ReleaseNotes/22.rst b/libcxx/docs/ReleaseNotes/22.rst index 25d33a9..980390c 100644 --- a/libcxx/docs/ReleaseNotes/22.rst +++ b/libcxx/docs/ReleaseNotes/22.rst @@ -76,8 +76,9 @@ Improvements and New Features - The ``std::{fill, fill_n}`` and ``std::ranges::{fill, fill_n}`` algorithms have been optimized for segmented iterators, resulting in a performance improvement of at least 10x for ``std::deque<int>`` iterators and ``std::join_view<std::vector<std::vector<int>>>`` iterators. -- The ``std::generate`` and ``std::generate_n`` algorithms have been optimized for segmented iterators, resulting in a - performance improvement for ``std::deque<short>`` and ``std::join_view<vector<vector<short>>>`` iterators. +- The ``std::{generate, generate_n}`` and ``std::ranges::generate_n`` algorithms have been optimized for segmented + iterators, resulting in a performance improvement for ``std::deque<short>`` and + ``std::join_view<vector<vector<short>>>`` iterators. Deprecations and Removals ------------------------- diff --git a/libcxx/include/__algorithm/generate_n.h b/libcxx/include/__algorithm/generate_n.h index e9da133..23899e4 100644 --- a/libcxx/include/__algorithm/generate_n.h +++ b/libcxx/include/__algorithm/generate_n.h @@ -13,22 +13,34 @@ #include <__config> #include <__functional/identity.h> #include <__utility/forward.h> +#include <__utility/move.h> #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) # pragma GCC system_header #endif +_LIBCPP_PUSH_MACROS +#include <__undef_macros> + _LIBCPP_BEGIN_NAMESPACE_STD template <class _OutputIterator, class _Size, class _Generator> inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator -generate_n(_OutputIterator __first, _Size __orig_n, _Generator __gen) { +__generate_n(_OutputIterator __first, _Size __orig_n, _Generator& __gen) { using __iter_ref = decltype(*__first); __identity __proj; auto __f = [&](__iter_ref __element) { std::forward<__iter_ref>(__element) = __gen(); }; - return std::__for_each_n(__first, __orig_n, __f, __proj); + return std::__for_each_n(std::move(__first), __orig_n, __f, __proj); +} + +template <class _OutputIterator, class _Size, class _Generator> +inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_SINCE_CXX20 _OutputIterator +generate_n(_OutputIterator __first, _Size __orig_n, _Generator __gen) { + return std::__generate_n(std::move(__first), __orig_n, __gen); } _LIBCPP_END_NAMESPACE_STD +_LIBCPP_POP_MACROS + #endif // _LIBCPP___ALGORITHM_GENERATE_N_H diff --git a/libcxx/include/__algorithm/ranges_generate_n.h b/libcxx/include/__algorithm/ranges_generate_n.h index a318994..0cc9ce7 100644 --- a/libcxx/include/__algorithm/ranges_generate_n.h +++ b/libcxx/include/__algorithm/ranges_generate_n.h @@ -9,6 +9,7 @@ #ifndef _LIBCPP___ALGORITHM_RANGES_GENERATE_N_H #define _LIBCPP___ALGORITHM_RANGES_GENERATE_N_H +#include <__algorithm/generate_n.h> #include <__concepts/constructible.h> #include <__concepts/invocable.h> #include <__config> @@ -38,12 +39,7 @@ struct __generate_n { requires invocable<_Func&> && indirectly_writable<_OutIter, invoke_result_t<_Func&>> _LIBCPP_HIDE_FROM_ABI constexpr _OutIter operator()(_OutIter __first, iter_difference_t<_OutIter> __n, _Func __gen) const { - for (; __n > 0; --__n) { - *__first = __gen(); - ++__first; - } - - return __first; + return std::__generate_n(std::move(__first), __n, __gen); } }; |
