[libc++][ranges] Implement ranges::contains_subrange

libcxx/docs/Status/RangesAlgorithms.csv

@@ -3,13 +3,13 @@ C++20,all C++20 algorithms,N/A,N/A,✅
 C++23,`find_last <https://wg21.link/P1223R5>`_,Unassigned,No patch yet,Not started
 C++23,`find_last_if <https://wg21.link/P1223R5>`_,Unassigned,No patch yet,Not started
 C++23,`find_last_if_not <https://wg21.link/P1223R5>`_,Unassigned,No patch yet,Not started
-C++23,`starts_with <https://wg21.link/P1659R3>`_,Zijun Zhao,`D150735 <https://llvm.org/D150735>`_,✅
-C++23,`ends_with <https://wg21.link/P1659R3>`_,Zijun Zhao,No patch yet,In Progress
+C++23,`starts_with <https://wg21.link/P1659R3>`_,Zijun Zhao,`D150735 <https://llvm.org/D150735>`_,Complete
+C++23,`ends_with <https://wg21.link/P1659R3>`_,Zijun Zhao, `D150831 <https://llvm.org/D150831>`_,Complete
 C++23,`shift_left <https://wg21.link/p2440r1>`_,Unassigned,No patch yet,Not started
 C++23,`shift_right <https://wg21.link/p2440r1>`_,Unassigned,No patch yet,Not started
 C++23,`iota (algorithm) <https://wg21.link/p2440r1>`_,Unassigned,No patch yet,Not started
 C++23,`fold <https://wg21.link/p2322r5>`_,Unassigned,No patch yet,Not started
-C++23,`contains <https://wg21.link/p2302r2>`_,Zijun Zhao,No patch yet,In Progress
+C++23,`contains <https://wg21.link/p2302r2>`_,Zijun Zhao, `#65148 <https://github.com/llvm/llvm-project/pull/65148>`_,Complete
 C++23,`fold_left_with_iter <https://wg21.link/p2322r6>`_,Christopher Di Bella,N/A,Complete
 C++23,`fold_left <https://wg21.link/p2322r6>`_,Christopher Di Bella,N/A,Complete
 C++23,`fold_left_first_with_iter <https://wg21.link/p2322r6>`_,Christopher Di Bella,N/A,In progress

libcxx/include/CMakeLists.txt

@@ -110,6 +110,7 @@ set(files
   __algorithm/ranges_binary_search.h
   __algorithm/ranges_clamp.h
   __algorithm/ranges_contains.h
+  __algorithm/ranges_contains_subrange.h
   __algorithm/ranges_copy.h
   __algorithm/ranges_copy_backward.h
   __algorithm/ranges_copy_if.h

libcxx/include/__algorithm/ranges_contains_subrange.h

@@ -0,0 +1,99 @@
+//===----------------------------------------------------------------------===//
+//
+// 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_CONTAINS_SUBRANGE_H
+#define _LIBCPP___ALGORITHM_RANGES_CONTAINS_SUBRANGE_H
+
+#include <__algorithm/ranges_search.h>
+#include <__config>
+#include <__functional/identity.h>
+#include <__functional/ranges_operations.h>
+#include <__functional/reference_wrapper.h>
+#include <__iterator/concepts.h>
+#include <__iterator/distance.h>
+#include <__iterator/indirectly_comparable.h>
+#include <__iterator/projected.h>
+#include <__ranges/access.h>
+#include <__ranges/concepts.h>
+#include <__ranges/subrange.h>
+#include <__utility/move.h>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_PUSH_MACROS
+#include <__undef_macros>
+
+#if _LIBCPP_STD_VER >= 23
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+namespace ranges {
+namespace __contains_subrange {
+struct __fn {
+  template <forward_iterator _Iter1,
+            sentinel_for<_Iter1> _Sent1,
+            forward_iterator _Iter2,
+            sentinel_for<_Iter2> _Sent2,
+            class _Pred  = ranges::equal_to,
+            class _Proj1 = identity,
+            class _Proj2 = identity>
+    requires indirectly_comparable<_Iter1, _Iter2, _Pred, _Proj1, _Proj2>
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr bool static operator()(
+      _Iter1 __first1,
+      _Sent1 __last1,
+      _Iter2 __first2,
+      _Sent2 __last2,
+      _Pred __pred   = {},
+      _Proj1 __proj1 = {},
+      _Proj2 __proj2 = {}) {
+    auto __n2 = ranges::distance(__first2, __last2);
+    if (__n2 == 0)
+      return true;
+
+    auto __ret = ranges::search(
+        std::move(__first1), __last1, std::move(__first2), __last2, __pred, std::ref(__proj1), std::ref(__proj2));
+    return __ret.empty() == false;
+  }
+
+  template <forward_range _Range1,
+            forward_range _Range2,
+            class _Pred  = ranges::equal_to,
+            class _Proj1 = identity,
+            class _Proj2 = identity>
+    requires indirectly_comparable<iterator_t<_Range1>, iterator_t<_Range2>, _Pred, _Proj1, _Proj2>
+  _LIBCPP_NODISCARD_EXT _LIBCPP_HIDE_FROM_ABI constexpr bool static
+  operator()(_Range1&& __range1, _Range2&& __range2, _Pred __pred = {}, _Proj1 __proj1 = {}, _Proj2 __proj2 = {}) {
+    auto __n2 = 0;
+    if constexpr (sized_range<_Range2>) {
+      __n2 = ranges::size(__range2);
+    } else {
+      __n2 = std::distance(cbegin(__range2), cend(__range2));
+    }
+    if (__n2 == 0)
+      return true;
+
+    auto __ret = ranges::search(__range1, __range2, __pred, std::ref(__proj1), std::ref(__proj2));
+    return __ret.empty() == false;
+  }
+};
+} // namespace __contains_subrange
+
+inline namespace __cpo {
+inline constexpr auto contains_subrange = __contains_subrange::__fn{};
+} // namespace __cpo
+} // namespace ranges
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP_STD_VER >= 23
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___ALGORITHM_RANGES_CONTAINS_SUBRANGE_H

libcxx/include/algorithm

@@ -217,6 +217,19 @@ namespace ranges {
     constexpr ranges::minmax_element_result<borrowed_iterator_t<R>>
       minmax_element(R&& r, Comp comp = {}, Proj proj = {});                                              // since C++20
 
+  template<forward_iterator I1, sentinel_for<I1> S1,
+           forward_iterator I2, sentinel_for<I2> S2,
+           class Pred = ranges::equal_to, class Proj1 = identity, class Proj2 = identity>
+    requires indirectly_comparable<I1, I2, Pred, Proj1, Proj2>
+    constexpr bool contains_subrange(I1 first1, S1 last1, I2 first2, S2 last2,
+                                     Pred pred = {}, Proj1 proj1 = {}, Proj2 proj2 = {});                // since C++23
+
+  template<forward_range R1, forward_range R2,
+           class Pred = ranges::equal_to, class Proj1 = identity, class Proj2 = identity>
+    requires indirectly_comparable<iterator_t<R1>, iterator_t<R2>, Pred, Proj1, Proj2>
+    constexpr bool contains_subrange(R1&& r1, R2&& r2, Pred pred = {},
+                                     Proj1 proj1 = {}, Proj2 proj2 = {});                                // since C++23
+
   template<class I, class O>
     using copy_result = in_out_result<I, O>;                                                // since C++20
 
@@ -1875,6 +1888,7 @@ template <class BidirectionalIterator, class Compare>
 #include <__algorithm/ranges_binary_search.h>
 #include <__algorithm/ranges_clamp.h>
 #include <__algorithm/ranges_contains.h>
+#include <__algorithm/ranges_contains_subrange.h>
 #include <__algorithm/ranges_copy.h>
 #include <__algorithm/ranges_copy_backward.h>
 #include <__algorithm/ranges_copy_if.h>

libcxx/include/libcxx.imp

@@ -110,6 +110,7 @@
   { include: [ "<__algorithm/ranges_binary_search.h>", "private", "<algorithm>", "public" ] },
   { include: [ "<__algorithm/ranges_clamp.h>", "private", "<algorithm>", "public" ] },
   { include: [ "<__algorithm/ranges_contains.h>", "private", "<algorithm>", "public" ] },
+  { include: [ "<__algorithm/ranges_contains_subrange.h>", "private", "<algorithm>", "public" ] },
   { include: [ "<__algorithm/ranges_copy.h>", "private", "<algorithm>", "public" ] },
   { include: [ "<__algorithm/ranges_copy_backward.h>", "private", "<algorithm>", "public" ] },
   { include: [ "<__algorithm/ranges_copy_if.h>", "private", "<algorithm>", "public" ] },

libcxx/include/module.modulemap.in

@@ -778,6 +778,7 @@ module std_private_algorithm_ranges_clamp                                [system
   export std_private_functional_ranges_operations
 }
 module std_private_algorithm_ranges_contains                             [system] { header "__algorithm/ranges_contains.h" }
+module std_private_algorithm_ranges_contains_subrange                    [system] { header "__algorithm/ranges_contains_subrange.h" }
 module std_private_algorithm_ranges_copy                                 [system] {
   header "__algorithm/ranges_copy.h"
   export std_private_algorithm_in_out_result

libcxx/modules/std/algorithm.inc

@@ -46,9 +46,7 @@ export namespace std {
   // [alg.contains], contains
   namespace ranges {
     using std::ranges::contains;
-#if 0
     using std::ranges::contains_subrange;
-#endif
   } // namespace ranges
 #endif // _LIBCPP_STD_VER >= 23
 

libcxx/test/libcxx/algorithms/ranges_robust_against_copying_projections.pass.cpp

@@ -86,6 +86,10 @@ constexpr bool all_the_algorithms()
     assert(copies == 0);
     (void)std::ranges::contains(a, value, Proj(&copies));
     assert(copies == 0);
+    (void)std::ranges::contains_subrange(first, last, first2, last2, Equal(), Proj(&copies), Proj(&copies));
+    assert(copies == 0);
+    (void)std::ranges::contains_subrange(a, b, Equal(), Proj(&copies), Proj(&copies));
+    assert(copies == 0);
 #endif
     (void)std::ranges::count(first, last, value, Proj(&copies)); assert(copies == 0);
     (void)std::ranges::count(a, value, Proj(&copies)); assert(copies == 0);

libcxx/test/libcxx/diagnostics/ranges.nodiscard_extensions.compile.pass.cpp

@@ -33,6 +33,8 @@ void test() {
 #if TEST_STD_VER >= 23
   std::ranges::contains(range, 1);
   std::ranges::contains(iter, iter, 1);
+  std::ranges::contains_subrange(range, range);
+  std::ranges::contains_subrange(iter, iter, iter, iter);
 #endif
   std::ranges::count_if(range, pred);
   std::ranges::count_if(iter, iter, pred);

libcxx/test/libcxx/diagnostics/ranges.nodiscard_extensions.verify.cpp

@@ -95,6 +95,10 @@ void test() {
   // expected-warning@-1{{ignoring return value of function declared with 'nodiscard' attribute}}
   std::ranges::contains(iter, iter, 1);
   // expected-warning@-1{{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::contains_subrange(range, range);
+  // expected-warning@-1 {{ignoring return value of function declared with 'nodiscard' attribute}}
+  std::ranges::contains_subrange(iter, iter, iter, iter);
+  // expected-warning@-1 {{ignoring return value of function declared with 'nodiscard' attribute}}
   std::ranges::fold_left(range, 0, std::plus());
   // expected-warning@-1{{ignoring return value of function declared with 'nodiscard' attribute}}
   std::ranges::fold_left(iter, iter, 0, std::plus());