[libcxx][ranges] implement `std::ranges::set_difference`
implement `std::ranges::set_difference`
reused classic std::set_difference
added unit tests
Differential Revision: https://reviews.llvm.org/D128983
NOKEYCHECK=True
GitOrigin-RevId: 1cdec6c96e852f4ebac61711a622535bcaf07542
diff --git a/include/CMakeLists.txt b/include/CMakeLists.txt
index 479c409..09ce7bf 100644
--- a/include/CMakeLists.txt
+++ b/include/CMakeLists.txt
@@ -108,6 +108,7 @@
__algorithm/ranges_replace.h
__algorithm/ranges_replace_if.h
__algorithm/ranges_reverse.h
+ __algorithm/ranges_set_difference.h
__algorithm/ranges_sort.h
__algorithm/ranges_stable_sort.h
__algorithm/ranges_swap_ranges.h
diff --git a/include/__algorithm/make_projected.h b/include/__algorithm/make_projected.h
index 8141c4e..6d8ebfd 100644
--- a/include/__algorithm/make_projected.h
+++ b/include/__algorithm/make_projected.h
@@ -13,6 +13,8 @@
#include <__config>
#include <__functional/identity.h>
#include <__functional/invoke.h>
+#include <__type_traits/decay.h>
+#include <__type_traits/is_member_pointer.h>
#include <__utility/forward.h>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
@@ -28,7 +30,7 @@
template <class _Comp, class _Proj>
_LIBCPP_HIDE_FROM_ABI constexpr static
decltype(auto) __make_projected_comp(_Comp& __comp, _Proj& __proj) {
- if constexpr (same_as<_Proj, identity>) {
+ if constexpr (same_as<decay_t<_Proj>, identity> && !is_member_pointer_v<decay_t<_Comp>>) {
// Avoid creating the lambda and just use the pristine comparator -- for certain algorithms, this would enable
// optimizations that rely on the type of the comparator.
return __comp;
@@ -42,6 +44,24 @@
}
}
+template <class _Comp, class _Proj1, class _Proj2>
+_LIBCPP_HIDE_FROM_ABI constexpr static
+decltype(auto) __make_projected_comp(_Comp& __comp, _Proj1& __proj1, _Proj2& __proj2) {
+ if constexpr (same_as<decay_t<_Proj1>, identity> && same_as<decay_t<_Proj2>, identity> &&
+ !is_member_pointer_v<decay_t<_Comp>>) {
+ // Avoid creating the lambda and just use the pristine comparator -- for certain algorithms, this would enable
+ // optimizations that rely on the type of the comparator.
+ return __comp;
+
+ } else {
+ return [&](auto&& __lhs, auto&& __rhs) {
+ return std::invoke(__comp,
+ std::invoke(__proj1, std::forward<decltype(__lhs)>(__lhs)),
+ std::invoke(__proj2, std::forward<decltype(__rhs)>(__rhs)));
+ };
+ }
+}
+
} // namespace ranges
_LIBCPP_END_NAMESPACE_STD
diff --git a/include/__algorithm/ranges_set_difference.h b/include/__algorithm/ranges_set_difference.h
new file mode 100644
index 0000000..4eb3efa
--- /dev/null
+++ b/include/__algorithm/ranges_set_difference.h
@@ -0,0 +1,104 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_RANGES_SET_DIFFERENCE_H
+#define _LIBCPP___ALGORITHM_RANGES_SET_DIFFERENCE_H
+
+#include <__algorithm/in_out_result.h>
+#include <__algorithm/make_projected.h>
+#include <__algorithm/set_difference.h>
+#include <__config>
+#include <__functional/identity.h>
+#include <__functional/invoke.h>
+#include <__functional/ranges_operations.h>
+#include <__iterator/concepts.h>
+#include <__iterator/mergeable.h>
+#include <__ranges/access.h>
+#include <__ranges/concepts.h>
+#include <__ranges/dangling.h>
+#include <__type_traits/decay.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+# pragma GCC system_header
+#endif
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace ranges {
+
+template <class _InIter, class _OutIter>
+using set_difference_result = in_out_result<_InIter, _OutIter>;
+
+namespace __set_difference {
+
+struct __fn {
+ template <
+ input_iterator _InIter1,
+ sentinel_for<_InIter1> _Sent1,
+ input_iterator _InIter2,
+ sentinel_for<_InIter2> _Sent2,
+ weakly_incrementable _OutIter,
+ class _Comp = less,
+ class _Proj1 = identity,
+ class _Proj2 = identity>
+ requires mergeable<_InIter1, _InIter2, _OutIter, _Comp, _Proj1, _Proj2>
+ _LIBCPP_HIDE_FROM_ABI constexpr set_difference_result<_InIter1, _OutIter> operator()(
+ _InIter1 __first1,
+ _Sent1 __last1,
+ _InIter2 __first2,
+ _Sent2 __last2,
+ _OutIter __result,
+ _Comp __comp = {},
+ _Proj1 __proj1 = {},
+ _Proj2 __proj2 = {}) const {
+ auto __ret = std::__set_difference(
+ __first1, __last1, __first2, __last2, __result, ranges::__make_projected_comp(__comp, __proj1, __proj2));
+ return {std::move(__ret.first), std::move(__ret.second)};
+ }
+
+ template <
+ input_range _Range1,
+ input_range _Range2,
+ weakly_incrementable _OutIter,
+ class _Comp = less,
+ class _Proj1 = identity,
+ class _Proj2 = identity>
+ requires mergeable<iterator_t<_Range1>, iterator_t<_Range2>, _OutIter, _Comp, _Proj1, _Proj2>
+ _LIBCPP_HIDE_FROM_ABI constexpr set_difference_result<borrowed_iterator_t<_Range1>, _OutIter>
+ operator()(
+ _Range1&& __range1,
+ _Range2&& __range2,
+ _OutIter __result,
+ _Comp __comp = {},
+ _Proj1 __proj1 = {},
+ _Proj2 __proj2 = {}) const {
+ auto __ret = std::__set_difference(
+ ranges::begin(__range1),
+ ranges::end(__range1),
+ ranges::begin(__range2),
+ ranges::end(__range2),
+ __result,
+ ranges::__make_projected_comp(__comp, __proj1, __proj2));
+ return {std::move(__ret.first), std::move(__ret.second)};
+ }
+};
+
+} // namespace __set_difference
+
+inline namespace __cpo {
+ inline constexpr auto set_difference = __set_difference::__fn{};
+} // namespace __cpo
+} // namespace ranges
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)
+#endif // _LIBCPP___ALGORITHM_RANGES_SET_DIFFERENCE_H
diff --git a/include/__algorithm/set_difference.h b/include/__algorithm/set_difference.h
index 5e2dca2..4378bd5 100644
--- a/include/__algorithm/set_difference.h
+++ b/include/__algorithm/set_difference.h
@@ -13,7 +13,12 @@
#include <__algorithm/comp_ref_type.h>
#include <__algorithm/copy.h>
#include <__config>
+#include <__functional/identity.h>
+#include <__functional/invoke.h>
#include <__iterator/iterator_traits.h>
+#include <__utility/move.h>
+#include <__utility/pair.h>
+#include <type_traits>
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
@@ -21,50 +26,52 @@
_LIBCPP_BEGIN_NAMESPACE_STD
-template <class _Compare, class _InputIterator1, class _InputIterator2, class _OutputIterator>
-_LIBCPP_CONSTEXPR_AFTER_CXX17 _OutputIterator
-__set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
- _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
-{
- while (__first1 != __last1)
- {
- if (__first2 == __last2)
- return _VSTD::copy(__first1, __last1, __result);
- if (__comp(*__first1, *__first2))
- {
- *__result = *__first1;
- ++__result;
- ++__first1;
- }
- else
- {
- if (!__comp(*__first2, *__first1))
- ++__first1;
- ++__first2;
- }
+template < class _Comp, class _InIter1, class _Sent1, class _InIter2, class _Sent2, class _OutIter>
+_LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 pair<__uncvref_t<_InIter1>, __uncvref_t<_OutIter> >
+__set_difference(
+ _InIter1&& __first1, _Sent1&& __last1, _InIter2&& __first2, _Sent2&& __last2, _OutIter&& __result, _Comp&& __comp) {
+ while (__first1 != __last1 && __first2 != __last2) {
+ if (__comp(*__first1, *__first2)) {
+ *__result = *__first1;
+ ++__first1;
+ ++__result;
+ } else if (__comp(*__first2, *__first1)) {
+ ++__first2;
+ } else {
+ ++__first1;
+ ++__first2;
}
- return __result;
+ }
+ return std::__copy(std::move(__first1), std::move(__last1), std::move(__result));
}
template <class _InputIterator1, class _InputIterator2, class _OutputIterator, class _Compare>
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
-_OutputIterator
-set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
- _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)
-{
- typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
- return _VSTD::__set_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp);
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 _OutputIterator set_difference(
+ _InputIterator1 __first1,
+ _InputIterator1 __last1,
+ _InputIterator2 __first2,
+ _InputIterator2 __last2,
+ _OutputIterator __result,
+ _Compare __comp) {
+ typedef typename __comp_ref_type<_Compare>::type _Comp_ref;
+ return std::__set_difference<_Comp_ref>(__first1, __last1, __first2, __last2, __result, __comp).second;
}
template <class _InputIterator1, class _InputIterator2, class _OutputIterator>
-inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17
-_OutputIterator
-set_difference(_InputIterator1 __first1, _InputIterator1 __last1,
- _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)
-{
- return _VSTD::set_difference(__first1, __last1, __first2, __last2, __result,
- __less<typename iterator_traits<_InputIterator1>::value_type,
- typename iterator_traits<_InputIterator2>::value_type>());
+inline _LIBCPP_HIDE_FROM_ABI _LIBCPP_CONSTEXPR_AFTER_CXX17 _OutputIterator set_difference(
+ _InputIterator1 __first1,
+ _InputIterator1 __last1,
+ _InputIterator2 __first2,
+ _InputIterator2 __last2,
+ _OutputIterator __result) {
+ return std::__set_difference(
+ __first1,
+ __last1,
+ __first2,
+ __last2,
+ __result,
+ __less<typename iterator_traits<_InputIterator1>::value_type,
+ typename iterator_traits<_InputIterator2>::value_type>()).second;
}
_LIBCPP_END_NAMESPACE_STD
diff --git a/include/algorithm b/include/algorithm
index a7236a3..fef1ad3 100644
--- a/include/algorithm
+++ b/include/algorithm
@@ -530,6 +530,24 @@
requires permutable<iterator_t<R>>
constexpr borrowed_subrange_t<R>
ranges::remove_if(R&& r, Pred pred, Proj proj = {}); // since C++20
+
+ template<class I, class O>
+ using set_difference_result = in_out_result<I, O>; // since C++20
+
+ template<input_iterator I1, sentinel_for<I1> S1, input_iterator I2, sentinel_for<I2> S2,
+ weakly_incrementable O, class Comp = ranges::less,
+ class Proj1 = identity, class Proj2 = identity>
+ requires mergeable<I1, I2, O, Comp, Proj1, Proj2>
+ constexpr set_difference_result<I1, O>
+ set_difference(I1 first1, S1 last1, I2 first2, S2 last2, O result,
+ Comp comp = {}, Proj1 proj1 = {}, Proj2 proj2 = {}); // since C++20
+
+ template<input_range R1, input_range R2, weakly_incrementable O,
+ class Comp = ranges::less, class Proj1 = identity, class Proj2 = identity>
+ requires mergeable<iterator_t<R1>, iterator_t<R2>, O, Comp, Proj1, Proj2>
+ constexpr set_difference_result<borrowed_iterator_t<R1>, O>
+ set_difference(R1&& r1, R2&& r2, O result,
+ Comp comp = {}, Proj1 proj1 = {}, Proj2 proj2 = {}); // since C++20
}
@@ -1300,6 +1318,7 @@
#include <__algorithm/ranges_replace.h>
#include <__algorithm/ranges_replace_if.h>
#include <__algorithm/ranges_reverse.h>
+#include <__algorithm/ranges_set_difference.h>
#include <__algorithm/ranges_sort.h>
#include <__algorithm/ranges_stable_sort.h>
#include <__algorithm/ranges_swap_ranges.h>
diff --git a/include/module.modulemap.in b/include/module.modulemap.in
index b547b50..98bb00b 100644
--- a/include/module.modulemap.in
+++ b/include/module.modulemap.in
@@ -347,6 +347,7 @@
module ranges_replace { private header "__algorithm/ranges_replace.h" }
module ranges_replace_if { private header "__algorithm/ranges_replace_if.h" }
module ranges_reverse { private header "__algorithm/ranges_reverse.h" }
+ module ranges_set_difference { private header "__algorithm/ranges_set_difference.h" }
module ranges_sort { private header "__algorithm/ranges_sort.h" }
module ranges_stable_sort { private header "__algorithm/ranges_stable_sort.h" }
module ranges_swap_ranges { private header "__algorithm/ranges_swap_ranges.h" }