[libc++][ranges] implement `std::ranges::unique{_copy}`
implement `std::ranges::unique` and `std::ranges::unique_copy`
Differential Revision: https://reviews.llvm.org/D130404
NOKEYCHECK=True
GitOrigin-RevId: 72f57e3a30d597346feec74cf626796b0055680f
diff --git a/include/algorithm b/include/algorithm
index 4fc353a..7b510b5 100644
--- a/include/algorithm
+++ b/include/algorithm
@@ -865,6 +865,34 @@
borrowed_iterator_t<R>
inplace_merge(R&& r, iterator_t<R> middle, Comp comp = {},
Proj proj = {}); // Since C++20
+
+ template<permutable I, sentinel_for<I> S, class Proj = identity,
+ indirect_equivalence_relation<projected<I, Proj>> C = ranges::equal_to>
+ constexpr subrange<I> unique(I first, S last, C comp = {}, Proj proj = {}); // Since C++20
+
+ template<forward_range R, class Proj = identity,
+ indirect_equivalence_relation<projected<iterator_t<R>, Proj>> C = ranges::equal_to>
+ requires permutable<iterator_t<R>>
+ constexpr borrowed_subrange_t<R>
+ unique(R&& r, C comp = {}, Proj proj = {}); // Since C++20
+
+ template<input_iterator I, sentinel_for<I> S, weakly_incrementable O, class Proj = identity,
+ indirect_equivalence_relation<projected<I, Proj>> C = ranges::equal_to>
+ requires indirectly_copyable<I, O> &&
+ (forward_iterator<I> ||
+ (input_iterator<O> && same_as<iter_value_t<I>, iter_value_t<O>>) ||
+ indirectly_copyable_storable<I, O>)
+ constexpr unique_copy_result<I, O>
+ unique_copy(I first, S last, O result, C comp = {}, Proj proj = {}); // Since C++20
+
+ template<input_range R, weakly_incrementable O, class Proj = identity,
+ indirect_equivalence_relation<projected<iterator_t<R>, Proj>> C = ranges::equal_to>
+ requires indirectly_copyable<iterator_t<R>, O> &&
+ (forward_iterator<iterator_t<R>> ||
+ (input_iterator<O> && same_as<range_value_t<R>, iter_value_t<O>>) ||
+ indirectly_copyable_storable<iterator_t<R>, O>)
+ constexpr unique_copy_result<borrowed_iterator_t<R>, O>
+ unique_copy(R&& r, O result, C comp = {}, Proj proj = {}); // Since C++20
}
constexpr bool // constexpr in C++20
@@ -1665,6 +1693,8 @@
#include <__algorithm/ranges_stable_sort.h>
#include <__algorithm/ranges_swap_ranges.h>
#include <__algorithm/ranges_transform.h>
+#include <__algorithm/ranges_unique.h>
+#include <__algorithm/ranges_unique_copy.h>
#include <__algorithm/ranges_upper_bound.h>
#include <__algorithm/remove.h>
#include <__algorithm/remove_copy.h>