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-rw-r--r--libcxx/docs/ReleaseNotes/22.rst5
-rw-r--r--libcxx/include/__algorithm/generate_n.h16
-rw-r--r--libcxx/include/__algorithm/ranges_generate_n.h8
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);
}
};