[1/3] libstdc++: Implement ranges::contains/contains_subrange from P2302R4

Message ID 20221114045047.362745-1-ppalka@redhat.com
State Accepted
Headers
Series [1/3] libstdc++: Implement ranges::contains/contains_subrange from P2302R4 |

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Context Check Description
snail/gcc-patch-check success Github commit url

Commit Message

Patrick Palka Nov. 14, 2022, 4:50 a.m. UTC
  Tested on x86_64-pc-linux-gnu, does this look OK for trunk?

libstdc++-v3/ChangeLog:

	* include/bits/ranges_algo.h (__contains_fn, contains): Define.
	(__contains_subrange_fn, contains_subrange): Define.
	* testsuite/25_algorithms/contains/1.cc: New test.
	* testsuite/25_algorithms/contains_subrange/1.cc: New test.
---
 libstdc++-v3/include/bits/ranges_algo.h       | 54 +++++++++++++++++++
 .../testsuite/25_algorithms/contains/1.cc     | 33 ++++++++++++
 .../25_algorithms/contains_subrange/1.cc      | 35 ++++++++++++
 3 files changed, 122 insertions(+)
 create mode 100644 libstdc++-v3/testsuite/25_algorithms/contains/1.cc
 create mode 100644 libstdc++-v3/testsuite/25_algorithms/contains_subrange/1.cc
  

Comments

Jonathan Wakely Nov. 14, 2022, 9:04 a.m. UTC | #1
On Mon, 14 Nov 2022 at 04:51, Patrick Palka via Libstdc++
<libstdc++@gcc.gnu.org> wrote:
>
> Tested on x86_64-pc-linux-gnu, does this look OK for trunk?
>
> libstdc++-v3/ChangeLog:
>
>         * include/bits/ranges_algo.h (__contains_fn, contains): Define.
>         (__contains_subrange_fn, contains_subrange): Define.
>         * testsuite/25_algorithms/contains/1.cc: New test.
>         * testsuite/25_algorithms/contains_subrange/1.cc: New test.
> ---
>  libstdc++-v3/include/bits/ranges_algo.h       | 54 +++++++++++++++++++
>  .../testsuite/25_algorithms/contains/1.cc     | 33 ++++++++++++
>  .../25_algorithms/contains_subrange/1.cc      | 35 ++++++++++++
>  3 files changed, 122 insertions(+)
>  create mode 100644 libstdc++-v3/testsuite/25_algorithms/contains/1.cc
>  create mode 100644 libstdc++-v3/testsuite/25_algorithms/contains_subrange/1.cc
>
> diff --git a/libstdc++-v3/include/bits/ranges_algo.h b/libstdc++-v3/include/bits/ranges_algo.h
> index de71bd07a2f..da0ca981dc3 100644
> --- a/libstdc++-v3/include/bits/ranges_algo.h
> +++ b/libstdc++-v3/include/bits/ranges_algo.h
> @@ -3464,6 +3464,60 @@ namespace ranges
>
>    inline constexpr __prev_permutation_fn prev_permutation{};
>
> +#if __cplusplus > 202002L
> +  struct __contains_fn
> +  {
> +    template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
> +           typename _Tp, typename _Proj = identity>
> +      requires indirect_binary_predicate<ranges::equal_to,
> +                                        projected<_Iter, _Proj>, const _Tp*>
> +      constexpr bool
> +      operator()(_Iter __first, _Sent __last, const _Tp& __value, _Proj __proj = {}) const
> +      { return ranges::find(std::move(__first), __last, __value, __proj) != __last; }

Should this use std::move(__proj)?



> +
> +    template<input_range _Range, typename _Tp, typename _Proj = identity>
> +      requires indirect_binary_predicate<ranges::equal_to,
> +                                        projected<iterator_t<_Range>, _Proj>, const _Tp*>
> +      constexpr bool
> +      operator()(_Range&& __r, const _Tp& __value, _Proj __proj = {}) const
> +      { return (*this)(ranges::begin(__r), ranges::end(__r), __value, std::move(__proj)); }
> +  };
> +
> +  inline constexpr __contains_fn contains{};
> +
> +  struct __contains_subrange_fn
> +  {
> +    template<forward_iterator _Iter1, sentinel_for<_Iter1> _Sent1,
> +            forward_iterator _Iter2, sentinel_for<_Iter2> _Sent2,
> +            typename _Pred = ranges::equal_to,
> +            typename Proj1 = identity, typename Proj2 = identity>
> +      requires indirectly_comparable<_Iter1, _Iter2, _Pred, Proj1, Proj2>
> +      constexpr bool
> +      operator()(_Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Sent2 __last2,
> +                _Pred __pred = {}, Proj1 __proj1 = {}, Proj2 __proj2 = {}) const
> +      {
> +       return __first2 == __last2
> +         || !ranges::search(__first1, __last1, __first2, __last2,
> +                            std::move(__pred), std::move(__proj1), std::move(__proj2)).empty();
> +      }
> +
> +    template<forward_range _Range1, forward_range _Range2,
> +            typename _Pred = ranges::equal_to,
> +            typename _Proj1 = identity, typename _Proj2 = identity>
> +      requires indirectly_comparable<iterator_t<_Range1>, iterator_t<_Range2>,
> +                                    _Pred, _Proj1, _Proj2>
> +      constexpr bool
> +      operator()(_Range1&& __r1, _Range2&& __r2, _Pred __pred = {},
> +                _Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
> +      {
> +       return (*this)(ranges::begin(__r1), ranges::end(__r1),
> +                      ranges::begin(__r2), ranges::end(__r2),
> +                      std::move(__pred), std::move(__proj1), std::move(__proj2));
> +      }
> +  };
> +
> +  inline constexpr __contains_subrange_fn contains_subrange{};
> +#endif // C++23
>  } // namespace ranges
>
>  #define __cpp_lib_shift 201806L
> diff --git a/libstdc++-v3/testsuite/25_algorithms/contains/1.cc b/libstdc++-v3/testsuite/25_algorithms/contains/1.cc
> new file mode 100644
> index 00000000000..146ab593b70
> --- /dev/null
> +++ b/libstdc++-v3/testsuite/25_algorithms/contains/1.cc
> @@ -0,0 +1,33 @@
> +// { dg-options "-std=gnu++23" }
> +// { dg-do run { target c++23 } }
> +
> +#include <algorithm>
> +#include <testsuite_hooks.h>
> +#include <testsuite_iterators.h>
> +
> +namespace ranges = std::ranges;
> +
> +void
> +test01()
> +{
> +  int x[] = {1,2,3};
> +  using to_input = __gnu_test::test_input_range<int>;
> +  VERIFY( ranges::contains(to_input(x), 1) );
> +  VERIFY( ranges::contains(to_input(x), 2) );
> +  VERIFY( ranges::contains(to_input(x), 3) );
> +  VERIFY( !ranges::contains(to_input(x), 4) );
> +  VERIFY( !ranges::contains(x, x+2, 3) );
> +  auto neg = [](int n) { return -n; };
> +  VERIFY( ranges::contains(to_input(x), -1, neg) );
> +  VERIFY( ranges::contains(to_input(x), -2, neg) );
> +  VERIFY( ranges::contains(to_input(x), -3, neg) );
> +  VERIFY( !ranges::contains(to_input(x), -4, neg) );
> +
> +  VERIFY( !ranges::contains(x, x+2, -3, neg) );
> +}
> +
> +int
> +main()
> +{
> +  test01();
> +}
> diff --git a/libstdc++-v3/testsuite/25_algorithms/contains_subrange/1.cc b/libstdc++-v3/testsuite/25_algorithms/contains_subrange/1.cc
> new file mode 100644
> index 00000000000..62b92795f94
> --- /dev/null
> +++ b/libstdc++-v3/testsuite/25_algorithms/contains_subrange/1.cc
> @@ -0,0 +1,35 @@
> +// { dg-options "-std=gnu++23" }
> +// { dg-do run { target c++23 } }
> +
> +#include <algorithm>
> +#include <testsuite_hooks.h>
> +#include <testsuite_iterators.h>
> +
> +namespace ranges = std::ranges;
> +
> +void
> +test01()
> +{
> +  int x[] = {1,2,3,4,5};
> +  int y[] = {2,3,4};
> +  int z[] = {4,5,6};
> +  __gnu_test::test_forward_range<int> rx(x);
> +  __gnu_test::test_forward_range<int> ry(y);
> +  __gnu_test::test_forward_range<int> rz(z);
> +  VERIFY( ranges::contains_subrange(rx, ry) );
> +  VERIFY( !ranges::contains_subrange(rx, rz) );
> +  VERIFY( ranges::contains_subrange(rx, ry, ranges::less{}) );
> +  VERIFY( ranges::contains_subrange(rx, rz, ranges::less{}) );
> +  auto plus3 = [](int n) { return n+3; };
> +  VERIFY( !ranges::contains_subrange(rx, ry, ranges::equal_to{}, plus3) );
> +  VERIFY( ranges::contains_subrange(rx, rz, ranges::equal_to{}, plus3) );
> +
> +  VERIFY( ranges::contains_subrange(x, x+2, y, y+1) );
> +  VERIFY( !ranges::contains_subrange(x, x+2, y, y+2) );
> +}
> +
> +int
> +main()
> +{
> +  test01();
> +}
> --
> 2.38.1.420.g319605f8f0
>
  
Patrick Palka Nov. 14, 2022, 3:07 p.m. UTC | #2
On Mon, 14 Nov 2022, Jonathan Wakely wrote:

> On Mon, 14 Nov 2022 at 04:51, Patrick Palka via Libstdc++
> <libstdc++@gcc.gnu.org> wrote:
> >
> > Tested on x86_64-pc-linux-gnu, does this look OK for trunk?
> >
> > libstdc++-v3/ChangeLog:
> >
> >         * include/bits/ranges_algo.h (__contains_fn, contains): Define.
> >         (__contains_subrange_fn, contains_subrange): Define.
> >         * testsuite/25_algorithms/contains/1.cc: New test.
> >         * testsuite/25_algorithms/contains_subrange/1.cc: New test.
> > ---
> >  libstdc++-v3/include/bits/ranges_algo.h       | 54 +++++++++++++++++++
> >  .../testsuite/25_algorithms/contains/1.cc     | 33 ++++++++++++
> >  .../25_algorithms/contains_subrange/1.cc      | 35 ++++++++++++
> >  3 files changed, 122 insertions(+)
> >  create mode 100644 libstdc++-v3/testsuite/25_algorithms/contains/1.cc
> >  create mode 100644 libstdc++-v3/testsuite/25_algorithms/contains_subrange/1.cc
> >
> > diff --git a/libstdc++-v3/include/bits/ranges_algo.h b/libstdc++-v3/include/bits/ranges_algo.h
> > index de71bd07a2f..da0ca981dc3 100644
> > --- a/libstdc++-v3/include/bits/ranges_algo.h
> > +++ b/libstdc++-v3/include/bits/ranges_algo.h
> > @@ -3464,6 +3464,60 @@ namespace ranges
> >
> >    inline constexpr __prev_permutation_fn prev_permutation{};
> >
> > +#if __cplusplus > 202002L
> > +  struct __contains_fn
> > +  {
> > +    template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
> > +           typename _Tp, typename _Proj = identity>
> > +      requires indirect_binary_predicate<ranges::equal_to,
> > +                                        projected<_Iter, _Proj>, const _Tp*>
> > +      constexpr bool
> > +      operator()(_Iter __first, _Sent __last, const _Tp& __value, _Proj __proj = {}) const
> > +      { return ranges::find(std::move(__first), __last, __value, __proj) != __last; }
> 
> Should this use std::move(__proj)?

Oops yes, IIUC std::move'ing projections isn't necessary since they're
copyable and equality preserving, but doing so is consistent with the
rest of the ranges algos which tend to std::move function objects.

-- >8 --

Subject: [PATCH 1/3] libstdc++: Implement ranges::contains/contains_subrange
 from P2302R4

libstdc++-v3/ChangeLog:

	* include/bits/ranges_algo.h (__contains_fn, contains): Define.
	(__contains_subrange_fn, contains_subrange): Define.
	* testsuite/25_algorithms/contains/1.cc: New test.
	* testsuite/25_algorithms/contains_subrange/1.cc: New test.
---
 libstdc++-v3/include/bits/ranges_algo.h       | 54 +++++++++++++++++++
 .../testsuite/25_algorithms/contains/1.cc     | 33 ++++++++++++
 .../25_algorithms/contains_subrange/1.cc      | 37 +++++++++++++
 3 files changed, 124 insertions(+)
 create mode 100644 libstdc++-v3/testsuite/25_algorithms/contains/1.cc
 create mode 100644 libstdc++-v3/testsuite/25_algorithms/contains_subrange/1.cc

diff --git a/libstdc++-v3/include/bits/ranges_algo.h b/libstdc++-v3/include/bits/ranges_algo.h
index de71bd07a2f..11206bdbcaa 100644
--- a/libstdc++-v3/include/bits/ranges_algo.h
+++ b/libstdc++-v3/include/bits/ranges_algo.h
@@ -3464,6 +3464,60 @@ namespace ranges
 
   inline constexpr __prev_permutation_fn prev_permutation{};
 
+#if __cplusplus > 202002L
+  struct __contains_fn
+  {
+    template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
+	    typename _Tp, typename _Proj = identity>
+      requires indirect_binary_predicate<ranges::equal_to,
+					 projected<_Iter, _Proj>, const _Tp*>
+      constexpr bool
+      operator()(_Iter __first, _Sent __last, const _Tp& __value, _Proj __proj = {}) const
+      { return ranges::find(std::move(__first), __last, __value, std::move(__proj)) != __last; }
+
+    template<input_range _Range, typename _Tp, typename _Proj = identity>
+      requires indirect_binary_predicate<ranges::equal_to,
+					 projected<iterator_t<_Range>, _Proj>, const _Tp*>
+      constexpr bool
+      operator()(_Range&& __r, const _Tp& __value, _Proj __proj = {}) const
+      { return (*this)(ranges::begin(__r), ranges::end(__r), __value, std::move(__proj)); }
+  };
+
+  inline constexpr __contains_fn contains{};
+
+  struct __contains_subrange_fn
+  {
+    template<forward_iterator _Iter1, sentinel_for<_Iter1> _Sent1,
+	     forward_iterator _Iter2, sentinel_for<_Iter2> _Sent2,
+	     typename _Pred = ranges::equal_to,
+	     typename Proj1 = identity, typename Proj2 = identity>
+      requires indirectly_comparable<_Iter1, _Iter2, _Pred, Proj1, Proj2>
+      constexpr bool
+      operator()(_Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Sent2 __last2,
+		 _Pred __pred = {}, Proj1 __proj1 = {}, Proj2 __proj2 = {}) const
+      {
+	return __first2 == __last2
+	  || !ranges::search(__first1, __last1, __first2, __last2,
+			     std::move(__pred), std::move(__proj1), std::move(__proj2)).empty();
+      }
+
+    template<forward_range _Range1, forward_range _Range2,
+	     typename _Pred = ranges::equal_to,
+	     typename _Proj1 = identity, typename _Proj2 = identity>
+      requires indirectly_comparable<iterator_t<_Range1>, iterator_t<_Range2>,
+				     _Pred, _Proj1, _Proj2>
+      constexpr bool
+      operator()(_Range1&& __r1, _Range2&& __r2, _Pred __pred = {},
+		 _Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
+      {
+	return (*this)(ranges::begin(__r1), ranges::end(__r1),
+		       ranges::begin(__r2), ranges::end(__r2),
+		       std::move(__pred), std::move(__proj1), std::move(__proj2));
+      }
+  };
+
+  inline constexpr __contains_subrange_fn contains_subrange{};
+#endif // C++23
 } // namespace ranges
 
 #define __cpp_lib_shift 201806L
diff --git a/libstdc++-v3/testsuite/25_algorithms/contains/1.cc b/libstdc++-v3/testsuite/25_algorithms/contains/1.cc
new file mode 100644
index 00000000000..146ab593b70
--- /dev/null
+++ b/libstdc++-v3/testsuite/25_algorithms/contains/1.cc
@@ -0,0 +1,33 @@
+// { dg-options "-std=gnu++23" }
+// { dg-do run { target c++23 } }
+
+#include <algorithm>
+#include <testsuite_hooks.h>
+#include <testsuite_iterators.h>
+
+namespace ranges = std::ranges;
+
+void
+test01()
+{
+  int x[] = {1,2,3};
+  using to_input = __gnu_test::test_input_range<int>;
+  VERIFY( ranges::contains(to_input(x), 1) );
+  VERIFY( ranges::contains(to_input(x), 2) );
+  VERIFY( ranges::contains(to_input(x), 3) );
+  VERIFY( !ranges::contains(to_input(x), 4) );
+  VERIFY( !ranges::contains(x, x+2, 3) );
+  auto neg = [](int n) { return -n; };
+  VERIFY( ranges::contains(to_input(x), -1, neg) );
+  VERIFY( ranges::contains(to_input(x), -2, neg) );
+  VERIFY( ranges::contains(to_input(x), -3, neg) );
+  VERIFY( !ranges::contains(to_input(x), -4, neg) );
+
+  VERIFY( !ranges::contains(x, x+2, -3, neg) );
+}
+
+int
+main()
+{
+  test01();
+}
diff --git a/libstdc++-v3/testsuite/25_algorithms/contains_subrange/1.cc b/libstdc++-v3/testsuite/25_algorithms/contains_subrange/1.cc
new file mode 100644
index 00000000000..6c3c99c0fd6
--- /dev/null
+++ b/libstdc++-v3/testsuite/25_algorithms/contains_subrange/1.cc
@@ -0,0 +1,37 @@
+// { dg-options "-std=gnu++23" }
+// { dg-do run { target c++23 } }
+
+#include <algorithm>
+#include <testsuite_hooks.h>
+#include <testsuite_iterators.h>
+
+namespace ranges = std::ranges;
+
+void
+test01()
+{
+  int x[] = {1,2,3,4,5};
+  int y[] = {2,3,4};
+  int z[] = {4,5,6};
+  __gnu_test::test_forward_range<int> rx(x);
+  __gnu_test::test_forward_range<int> ry(y);
+  __gnu_test::test_forward_range<int> rz(z);
+  VERIFY( ranges::contains_subrange(rx, ry) );
+  VERIFY( !ranges::contains_subrange(rx, rz) );
+  VERIFY( ranges::contains_subrange(rx, ry, ranges::less{}) );
+  VERIFY( ranges::contains_subrange(rx, rz, ranges::less{}) );
+  auto plus3 = [](int n) { return n+3; };
+  VERIFY( !ranges::contains_subrange(rx, ry, {}, plus3) );
+  VERIFY( ranges::contains_subrange(rx, rz, {}, plus3) );
+  VERIFY( ranges::contains_subrange(rx, ry, {}, plus3, plus3) );
+  VERIFY( !ranges::contains_subrange(rx, rz, {}, plus3, plus3) );
+
+  VERIFY( ranges::contains_subrange(x, x+2, y, y+1) );
+  VERIFY( !ranges::contains_subrange(x, x+2, y, y+2) );
+}
+
+int
+main()
+{
+  test01();
+}
  
Jonathan Wakely Nov. 14, 2022, 3:09 p.m. UTC | #3
On Mon, 14 Nov 2022 at 15:07, Patrick Palka <ppalka@redhat.com> wrote:
>
> On Mon, 14 Nov 2022, Jonathan Wakely wrote:
>
> > On Mon, 14 Nov 2022 at 04:51, Patrick Palka via Libstdc++
> > <libstdc++@gcc.gnu.org> wrote:
> > >
> > > Tested on x86_64-pc-linux-gnu, does this look OK for trunk?
> > >
> > > libstdc++-v3/ChangeLog:
> > >
> > >         * include/bits/ranges_algo.h (__contains_fn, contains): Define.
> > >         (__contains_subrange_fn, contains_subrange): Define.
> > >         * testsuite/25_algorithms/contains/1.cc: New test.
> > >         * testsuite/25_algorithms/contains_subrange/1.cc: New test.
> > > ---
> > >  libstdc++-v3/include/bits/ranges_algo.h       | 54 +++++++++++++++++++
> > >  .../testsuite/25_algorithms/contains/1.cc     | 33 ++++++++++++
> > >  .../25_algorithms/contains_subrange/1.cc      | 35 ++++++++++++
> > >  3 files changed, 122 insertions(+)
> > >  create mode 100644 libstdc++-v3/testsuite/25_algorithms/contains/1.cc
> > >  create mode 100644 libstdc++-v3/testsuite/25_algorithms/contains_subrange/1.cc
> > >
> > > diff --git a/libstdc++-v3/include/bits/ranges_algo.h b/libstdc++-v3/include/bits/ranges_algo.h
> > > index de71bd07a2f..da0ca981dc3 100644
> > > --- a/libstdc++-v3/include/bits/ranges_algo.h
> > > +++ b/libstdc++-v3/include/bits/ranges_algo.h
> > > @@ -3464,6 +3464,60 @@ namespace ranges
> > >
> > >    inline constexpr __prev_permutation_fn prev_permutation{};
> > >
> > > +#if __cplusplus > 202002L
> > > +  struct __contains_fn
> > > +  {
> > > +    template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
> > > +           typename _Tp, typename _Proj = identity>
> > > +      requires indirect_binary_predicate<ranges::equal_to,
> > > +                                        projected<_Iter, _Proj>, const _Tp*>
> > > +      constexpr bool
> > > +      operator()(_Iter __first, _Sent __last, const _Tp& __value, _Proj __proj = {}) const
> > > +      { return ranges::find(std::move(__first), __last, __value, __proj) != __last; }
> >
> > Should this use std::move(__proj)?
>
> Oops yes, IIUC std::move'ing projections isn't necessary since they're
> copyable and equality preserving, but doing so is consistent with the
> rest of the ranges algos which tend to std::move function objects.

Revised patch is OK for trunk, thanks.

>
> -- >8 --
>
> Subject: [PATCH 1/3] libstdc++: Implement ranges::contains/contains_subrange
>  from P2302R4
>
> libstdc++-v3/ChangeLog:
>
>         * include/bits/ranges_algo.h (__contains_fn, contains): Define.
>         (__contains_subrange_fn, contains_subrange): Define.
>         * testsuite/25_algorithms/contains/1.cc: New test.
>         * testsuite/25_algorithms/contains_subrange/1.cc: New test.
> ---
>  libstdc++-v3/include/bits/ranges_algo.h       | 54 +++++++++++++++++++
>  .../testsuite/25_algorithms/contains/1.cc     | 33 ++++++++++++
>  .../25_algorithms/contains_subrange/1.cc      | 37 +++++++++++++
>  3 files changed, 124 insertions(+)
>  create mode 100644 libstdc++-v3/testsuite/25_algorithms/contains/1.cc
>  create mode 100644 libstdc++-v3/testsuite/25_algorithms/contains_subrange/1.cc
>
> diff --git a/libstdc++-v3/include/bits/ranges_algo.h b/libstdc++-v3/include/bits/ranges_algo.h
> index de71bd07a2f..11206bdbcaa 100644
> --- a/libstdc++-v3/include/bits/ranges_algo.h
> +++ b/libstdc++-v3/include/bits/ranges_algo.h
> @@ -3464,6 +3464,60 @@ namespace ranges
>
>    inline constexpr __prev_permutation_fn prev_permutation{};
>
> +#if __cplusplus > 202002L
> +  struct __contains_fn
> +  {
> +    template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
> +           typename _Tp, typename _Proj = identity>
> +      requires indirect_binary_predicate<ranges::equal_to,
> +                                        projected<_Iter, _Proj>, const _Tp*>
> +      constexpr bool
> +      operator()(_Iter __first, _Sent __last, const _Tp& __value, _Proj __proj = {}) const
> +      { return ranges::find(std::move(__first), __last, __value, std::move(__proj)) != __last; }
> +
> +    template<input_range _Range, typename _Tp, typename _Proj = identity>
> +      requires indirect_binary_predicate<ranges::equal_to,
> +                                        projected<iterator_t<_Range>, _Proj>, const _Tp*>
> +      constexpr bool
> +      operator()(_Range&& __r, const _Tp& __value, _Proj __proj = {}) const
> +      { return (*this)(ranges::begin(__r), ranges::end(__r), __value, std::move(__proj)); }
> +  };
> +
> +  inline constexpr __contains_fn contains{};
> +
> +  struct __contains_subrange_fn
> +  {
> +    template<forward_iterator _Iter1, sentinel_for<_Iter1> _Sent1,
> +            forward_iterator _Iter2, sentinel_for<_Iter2> _Sent2,
> +            typename _Pred = ranges::equal_to,
> +            typename Proj1 = identity, typename Proj2 = identity>
> +      requires indirectly_comparable<_Iter1, _Iter2, _Pred, Proj1, Proj2>
> +      constexpr bool
> +      operator()(_Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Sent2 __last2,
> +                _Pred __pred = {}, Proj1 __proj1 = {}, Proj2 __proj2 = {}) const
> +      {
> +       return __first2 == __last2
> +         || !ranges::search(__first1, __last1, __first2, __last2,
> +                            std::move(__pred), std::move(__proj1), std::move(__proj2)).empty();
> +      }
> +
> +    template<forward_range _Range1, forward_range _Range2,
> +            typename _Pred = ranges::equal_to,
> +            typename _Proj1 = identity, typename _Proj2 = identity>
> +      requires indirectly_comparable<iterator_t<_Range1>, iterator_t<_Range2>,
> +                                    _Pred, _Proj1, _Proj2>
> +      constexpr bool
> +      operator()(_Range1&& __r1, _Range2&& __r2, _Pred __pred = {},
> +                _Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
> +      {
> +       return (*this)(ranges::begin(__r1), ranges::end(__r1),
> +                      ranges::begin(__r2), ranges::end(__r2),
> +                      std::move(__pred), std::move(__proj1), std::move(__proj2));
> +      }
> +  };
> +
> +  inline constexpr __contains_subrange_fn contains_subrange{};
> +#endif // C++23
>  } // namespace ranges
>
>  #define __cpp_lib_shift 201806L
> diff --git a/libstdc++-v3/testsuite/25_algorithms/contains/1.cc b/libstdc++-v3/testsuite/25_algorithms/contains/1.cc
> new file mode 100644
> index 00000000000..146ab593b70
> --- /dev/null
> +++ b/libstdc++-v3/testsuite/25_algorithms/contains/1.cc
> @@ -0,0 +1,33 @@
> +// { dg-options "-std=gnu++23" }
> +// { dg-do run { target c++23 } }
> +
> +#include <algorithm>
> +#include <testsuite_hooks.h>
> +#include <testsuite_iterators.h>
> +
> +namespace ranges = std::ranges;
> +
> +void
> +test01()
> +{
> +  int x[] = {1,2,3};
> +  using to_input = __gnu_test::test_input_range<int>;
> +  VERIFY( ranges::contains(to_input(x), 1) );
> +  VERIFY( ranges::contains(to_input(x), 2) );
> +  VERIFY( ranges::contains(to_input(x), 3) );
> +  VERIFY( !ranges::contains(to_input(x), 4) );
> +  VERIFY( !ranges::contains(x, x+2, 3) );
> +  auto neg = [](int n) { return -n; };
> +  VERIFY( ranges::contains(to_input(x), -1, neg) );
> +  VERIFY( ranges::contains(to_input(x), -2, neg) );
> +  VERIFY( ranges::contains(to_input(x), -3, neg) );
> +  VERIFY( !ranges::contains(to_input(x), -4, neg) );
> +
> +  VERIFY( !ranges::contains(x, x+2, -3, neg) );
> +}
> +
> +int
> +main()
> +{
> +  test01();
> +}
> diff --git a/libstdc++-v3/testsuite/25_algorithms/contains_subrange/1.cc b/libstdc++-v3/testsuite/25_algorithms/contains_subrange/1.cc
> new file mode 100644
> index 00000000000..6c3c99c0fd6
> --- /dev/null
> +++ b/libstdc++-v3/testsuite/25_algorithms/contains_subrange/1.cc
> @@ -0,0 +1,37 @@
> +// { dg-options "-std=gnu++23" }
> +// { dg-do run { target c++23 } }
> +
> +#include <algorithm>
> +#include <testsuite_hooks.h>
> +#include <testsuite_iterators.h>
> +
> +namespace ranges = std::ranges;
> +
> +void
> +test01()
> +{
> +  int x[] = {1,2,3,4,5};
> +  int y[] = {2,3,4};
> +  int z[] = {4,5,6};
> +  __gnu_test::test_forward_range<int> rx(x);
> +  __gnu_test::test_forward_range<int> ry(y);
> +  __gnu_test::test_forward_range<int> rz(z);
> +  VERIFY( ranges::contains_subrange(rx, ry) );
> +  VERIFY( !ranges::contains_subrange(rx, rz) );
> +  VERIFY( ranges::contains_subrange(rx, ry, ranges::less{}) );
> +  VERIFY( ranges::contains_subrange(rx, rz, ranges::less{}) );
> +  auto plus3 = [](int n) { return n+3; };
> +  VERIFY( !ranges::contains_subrange(rx, ry, {}, plus3) );
> +  VERIFY( ranges::contains_subrange(rx, rz, {}, plus3) );
> +  VERIFY( ranges::contains_subrange(rx, ry, {}, plus3, plus3) );
> +  VERIFY( !ranges::contains_subrange(rx, rz, {}, plus3, plus3) );
> +
> +  VERIFY( ranges::contains_subrange(x, x+2, y, y+1) );
> +  VERIFY( !ranges::contains_subrange(x, x+2, y, y+2) );
> +}
> +
> +int
> +main()
> +{
> +  test01();
> +}
> --
> 2.38.1.420.g319605f8f0
>
  

Patch

diff --git a/libstdc++-v3/include/bits/ranges_algo.h b/libstdc++-v3/include/bits/ranges_algo.h
index de71bd07a2f..da0ca981dc3 100644
--- a/libstdc++-v3/include/bits/ranges_algo.h
+++ b/libstdc++-v3/include/bits/ranges_algo.h
@@ -3464,6 +3464,60 @@  namespace ranges
 
   inline constexpr __prev_permutation_fn prev_permutation{};
 
+#if __cplusplus > 202002L
+  struct __contains_fn
+  {
+    template<input_iterator _Iter, sentinel_for<_Iter> _Sent,
+	    typename _Tp, typename _Proj = identity>
+      requires indirect_binary_predicate<ranges::equal_to,
+					 projected<_Iter, _Proj>, const _Tp*>
+      constexpr bool
+      operator()(_Iter __first, _Sent __last, const _Tp& __value, _Proj __proj = {}) const
+      { return ranges::find(std::move(__first), __last, __value, __proj) != __last; }
+
+    template<input_range _Range, typename _Tp, typename _Proj = identity>
+      requires indirect_binary_predicate<ranges::equal_to,
+					 projected<iterator_t<_Range>, _Proj>, const _Tp*>
+      constexpr bool
+      operator()(_Range&& __r, const _Tp& __value, _Proj __proj = {}) const
+      { return (*this)(ranges::begin(__r), ranges::end(__r), __value, std::move(__proj)); }
+  };
+
+  inline constexpr __contains_fn contains{};
+
+  struct __contains_subrange_fn
+  {
+    template<forward_iterator _Iter1, sentinel_for<_Iter1> _Sent1,
+	     forward_iterator _Iter2, sentinel_for<_Iter2> _Sent2,
+	     typename _Pred = ranges::equal_to,
+	     typename Proj1 = identity, typename Proj2 = identity>
+      requires indirectly_comparable<_Iter1, _Iter2, _Pred, Proj1, Proj2>
+      constexpr bool
+      operator()(_Iter1 __first1, _Sent1 __last1, _Iter2 __first2, _Sent2 __last2,
+		 _Pred __pred = {}, Proj1 __proj1 = {}, Proj2 __proj2 = {}) const
+      {
+	return __first2 == __last2
+	  || !ranges::search(__first1, __last1, __first2, __last2,
+			     std::move(__pred), std::move(__proj1), std::move(__proj2)).empty();
+      }
+
+    template<forward_range _Range1, forward_range _Range2,
+	     typename _Pred = ranges::equal_to,
+	     typename _Proj1 = identity, typename _Proj2 = identity>
+      requires indirectly_comparable<iterator_t<_Range1>, iterator_t<_Range2>,
+				     _Pred, _Proj1, _Proj2>
+      constexpr bool
+      operator()(_Range1&& __r1, _Range2&& __r2, _Pred __pred = {},
+		 _Proj1 __proj1 = {}, _Proj2 __proj2 = {}) const
+      {
+	return (*this)(ranges::begin(__r1), ranges::end(__r1),
+		       ranges::begin(__r2), ranges::end(__r2),
+		       std::move(__pred), std::move(__proj1), std::move(__proj2));
+      }
+  };
+
+  inline constexpr __contains_subrange_fn contains_subrange{};
+#endif // C++23
 } // namespace ranges
 
 #define __cpp_lib_shift 201806L
diff --git a/libstdc++-v3/testsuite/25_algorithms/contains/1.cc b/libstdc++-v3/testsuite/25_algorithms/contains/1.cc
new file mode 100644
index 00000000000..146ab593b70
--- /dev/null
+++ b/libstdc++-v3/testsuite/25_algorithms/contains/1.cc
@@ -0,0 +1,33 @@ 
+// { dg-options "-std=gnu++23" }
+// { dg-do run { target c++23 } }
+
+#include <algorithm>
+#include <testsuite_hooks.h>
+#include <testsuite_iterators.h>
+
+namespace ranges = std::ranges;
+
+void
+test01()
+{
+  int x[] = {1,2,3};
+  using to_input = __gnu_test::test_input_range<int>;
+  VERIFY( ranges::contains(to_input(x), 1) );
+  VERIFY( ranges::contains(to_input(x), 2) );
+  VERIFY( ranges::contains(to_input(x), 3) );
+  VERIFY( !ranges::contains(to_input(x), 4) );
+  VERIFY( !ranges::contains(x, x+2, 3) );
+  auto neg = [](int n) { return -n; };
+  VERIFY( ranges::contains(to_input(x), -1, neg) );
+  VERIFY( ranges::contains(to_input(x), -2, neg) );
+  VERIFY( ranges::contains(to_input(x), -3, neg) );
+  VERIFY( !ranges::contains(to_input(x), -4, neg) );
+
+  VERIFY( !ranges::contains(x, x+2, -3, neg) );
+}
+
+int
+main()
+{
+  test01();
+}
diff --git a/libstdc++-v3/testsuite/25_algorithms/contains_subrange/1.cc b/libstdc++-v3/testsuite/25_algorithms/contains_subrange/1.cc
new file mode 100644
index 00000000000..62b92795f94
--- /dev/null
+++ b/libstdc++-v3/testsuite/25_algorithms/contains_subrange/1.cc
@@ -0,0 +1,35 @@ 
+// { dg-options "-std=gnu++23" }
+// { dg-do run { target c++23 } }
+
+#include <algorithm>
+#include <testsuite_hooks.h>
+#include <testsuite_iterators.h>
+
+namespace ranges = std::ranges;
+
+void
+test01()
+{
+  int x[] = {1,2,3,4,5};
+  int y[] = {2,3,4};
+  int z[] = {4,5,6};
+  __gnu_test::test_forward_range<int> rx(x);
+  __gnu_test::test_forward_range<int> ry(y);
+  __gnu_test::test_forward_range<int> rz(z);
+  VERIFY( ranges::contains_subrange(rx, ry) );
+  VERIFY( !ranges::contains_subrange(rx, rz) );
+  VERIFY( ranges::contains_subrange(rx, ry, ranges::less{}) );
+  VERIFY( ranges::contains_subrange(rx, rz, ranges::less{}) );
+  auto plus3 = [](int n) { return n+3; };
+  VERIFY( !ranges::contains_subrange(rx, ry, ranges::equal_to{}, plus3) );
+  VERIFY( ranges::contains_subrange(rx, rz, ranges::equal_to{}, plus3) );
+
+  VERIFY( ranges::contains_subrange(x, x+2, y, y+1) );
+  VERIFY( !ranges::contains_subrange(x, x+2, y, y+2) );
+}
+
+int
+main()
+{
+  test01();
+}