1 files changed, 168 insertions, 0 deletions

diff --git a/contrib/llvm-project/libcxx/include/__algorithm/is_permutation.h b/contrib/llvm-project/libcxx/include/__algorithm/is_permutation.h
new file mode 100644
index 000000000000..0545eb76370a
--- /dev/null
+++ b/contrib/llvm-project/libcxx/include/__algorithm/is_permutation.h
@@ -0,0 +1,168 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// 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_IS_PERMUTATION_H
+#define _LIBCPP___ALGORITHM_IS_PERMUTATION_H
+
+#include <__algorithm/comp.h>
+#include <__config>
+#include <__iterator/iterator_traits.h>
+#include <__iterator/next.h>
+#include <iterator> // FIXME: replace with <__iterator/distance.h> when it lands
+
+#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 _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+_LIBCPP_NODISCARD_EXT _LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+               _BinaryPredicate __pred) {
+  //  shorten sequences as much as possible by lopping of any equal prefix
+  for (; __first1 != __last1; ++__first1, (void)++__first2)
+    if (!__pred(*__first1, *__first2))
+      break;
+  if (__first1 == __last1)
+    return true;
+
+  //  __first1 != __last1 && *__first1 != *__first2
+  typedef typename iterator_traits<_ForwardIterator1>::difference_type _D1;
+  _D1 __l1 = _VSTD::distance(__first1, __last1);
+  if (__l1 == _D1(1))
+    return false;
+  _ForwardIterator2 __last2 = _VSTD::next(__first2, __l1);
+  // For each element in [f1, l1) see if there are the same number of
+  //    equal elements in [f2, l2)
+  for (_ForwardIterator1 __i = __first1; __i != __last1; ++__i) {
+    //  Have we already counted the number of *__i in [f1, l1)?
+    _ForwardIterator1 __match = __first1;
+    for (; __match != __i; ++__match)
+      if (__pred(*__match, *__i))
+        break;
+    if (__match == __i) {
+      // Count number of *__i in [f2, l2)
+      _D1 __c2 = 0;
+      for (_ForwardIterator2 __j = __first2; __j != __last2; ++__j)
+        if (__pred(*__i, *__j))
+          ++__c2;
+      if (__c2 == 0)
+        return false;
+      // Count number of *__i in [__i, l1) (we can start with 1)
+      _D1 __c1 = 1;
+      for (_ForwardIterator1 __j = _VSTD::next(__i); __j != __last1; ++__j)
+        if (__pred(*__i, *__j))
+          ++__c1;
+      if (__c1 != __c2)
+        return false;
+    }
+  }
+  return true;
+}
+
+template <class _ForwardIterator1, class _ForwardIterator2>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2) {
+  typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
+  typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
+  return _VSTD::is_permutation(__first1, __last1, __first2, __equal_to<__v1, __v2>());
+}
+
+#if _LIBCPP_STD_VER > 11
+template <class _BinaryPredicate, class _ForwardIterator1, class _ForwardIterator2>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+__is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+                 _ForwardIterator2 __last2, _BinaryPredicate __pred, forward_iterator_tag, forward_iterator_tag) {
+  //  shorten sequences as much as possible by lopping of any equal prefix
+  for (; __first1 != __last1 && __first2 != __last2; ++__first1, (void)++__first2)
+    if (!__pred(*__first1, *__first2))
+      break;
+  if (__first1 == __last1)
+    return __first2 == __last2;
+  else if (__first2 == __last2)
+    return false;
+
+  typedef typename iterator_traits<_ForwardIterator1>::difference_type _D1;
+  _D1 __l1 = _VSTD::distance(__first1, __last1);
+
+  typedef typename iterator_traits<_ForwardIterator2>::difference_type _D2;
+  _D2 __l2 = _VSTD::distance(__first2, __last2);
+  if (__l1 != __l2)
+    return false;
+
+  // For each element in [f1, l1) see if there are the same number of
+  //    equal elements in [f2, l2)
+  for (_ForwardIterator1 __i = __first1; __i != __last1; ++__i) {
+    //  Have we already counted the number of *__i in [f1, l1)?
+    _ForwardIterator1 __match = __first1;
+    for (; __match != __i; ++__match)
+      if (__pred(*__match, *__i))
+        break;
+    if (__match == __i) {
+      // Count number of *__i in [f2, l2)
+      _D1 __c2 = 0;
+      for (_ForwardIterator2 __j = __first2; __j != __last2; ++__j)
+        if (__pred(*__i, *__j))
+          ++__c2;
+      if (__c2 == 0)
+        return false;
+      // Count number of *__i in [__i, l1) (we can start with 1)
+      _D1 __c1 = 1;
+      for (_ForwardIterator1 __j = _VSTD::next(__i); __j != __last1; ++__j)
+        if (__pred(*__i, *__j))
+          ++__c1;
+      if (__c1 != __c2)
+        return false;
+    }
+  }
+  return true;
+}
+
+template <class _BinaryPredicate, class _RandomAccessIterator1, class _RandomAccessIterator2>
+_LIBCPP_CONSTEXPR_AFTER_CXX17 bool __is_permutation(_RandomAccessIterator1 __first1, _RandomAccessIterator2 __last1,
+                                                    _RandomAccessIterator1 __first2, _RandomAccessIterator2 __last2,
+                                                    _BinaryPredicate __pred, random_access_iterator_tag,
+                                                    random_access_iterator_tag) {
+  if (_VSTD::distance(__first1, __last1) != _VSTD::distance(__first2, __last2))
+    return false;
+  return _VSTD::is_permutation<_RandomAccessIterator1, _RandomAccessIterator2,
+                               typename add_lvalue_reference<_BinaryPredicate>::type>(__first1, __last1, __first2,
+                                                                                      __pred);
+}
+
+template <class _ForwardIterator1, class _ForwardIterator2, class _BinaryPredicate>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+               _ForwardIterator2 __last2, _BinaryPredicate __pred) {
+  return _VSTD::__is_permutation<typename add_lvalue_reference<_BinaryPredicate>::type>(
+      __first1, __last1, __first2, __last2, __pred, typename iterator_traits<_ForwardIterator1>::iterator_category(),
+      typename iterator_traits<_ForwardIterator2>::iterator_category());
+}
+
+template <class _ForwardIterator1, class _ForwardIterator2>
+_LIBCPP_NODISCARD_EXT inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_AFTER_CXX17 bool
+is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1, _ForwardIterator2 __first2,
+               _ForwardIterator2 __last2) {
+  typedef typename iterator_traits<_ForwardIterator1>::value_type __v1;
+  typedef typename iterator_traits<_ForwardIterator2>::value_type __v2;
+  return _VSTD::__is_permutation(__first1, __last1, __first2, __last2, __equal_to<__v1, __v2>(),
+                                 typename iterator_traits<_ForwardIterator1>::iterator_category(),
+                                 typename iterator_traits<_ForwardIterator2>::iterator_category());
+}
+#endif
+
+_LIBCPP_END_NAMESPACE_STD
+
+_LIBCPP_POP_MACROS
+
+#endif // _LIBCPP___ALGORITHM_IS_PERMUTATION_H