text: // -*- C++ -*-
  //===-- is_sorted.pass.cpp ------------------------------------------------===//
  //
  // 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
  //
  //===----------------------------------------------------------------------===//
  
  // UNSUPPORTED: c++03, c++11, c++14
  
  #include "support/pstl_test_config.h"
  
  #include <execution>
  #include <algorithm>
  
  #include "support/utils.h"
  
  using namespace TestUtils;
  
  struct test_is_sorted
  {
      template <typename Policy, typename Iterator>
      void
      operator()(Policy&& exec, Iterator first, Iterator last, bool exam)
      {
          using namespace std;
          typedef typename std::iterator_traits<Iterator>::value_type T;
  
          //try random-access iterator
          bool res = is_sorted(exec, first, last);
          EXPECT_TRUE(exam == res, "is_sorted wrong result for random-access iterator");
          auto iexam = is_sorted_until(first, last);
          auto ires = is_sorted_until(exec, first, last);
          EXPECT_TRUE(iexam == ires, "is_sorted_until wrong result for random-access iterator");
  
          //try random-access iterator with a predicate
          res = is_sorted(exec, first, last, std::less<T>());
          EXPECT_TRUE(exam == res, "is_sorted wrong result for random-access iterator");
          iexam = is_sorted_until(first, last, std::less<T>());
          ires = is_sorted_until(exec, first, last, std::less<T>());
          EXPECT_TRUE(iexam == ires, "is_sorted_until wrong result for random-access iterator");
      }
  };
  
  template <typename T>
  void
  test_is_sorted_by_type()
  {
  
      Sequence<T> in(99999, [](size_t v) -> T { return T(v); }); //fill 0..n
  
      invoke_on_all_policies(test_is_sorted(), in.begin(), in.end(), std::is_sorted(in.begin(), in.end()));
      invoke_on_all_policies(test_is_sorted(), in.cbegin(), in.cend(), std::is_sorted(in.begin(), in.end()));
  
      in[in.size() / 2] = -1;
      invoke_on_all_policies(test_is_sorted(), in.begin(), in.end(), std::is_sorted(in.begin(), in.end()));
      invoke_on_all_policies(test_is_sorted(), in.cbegin(), in.cend(), std::is_sorted(in.begin(), in.end()));
  
      in[1] = -1;
      invoke_on_all_policies(test_is_sorted(), in.begin(), in.end(), std::is_sorted(in.begin(), in.end()));
      invoke_on_all_policies(test_is_sorted(), in.cbegin(), in.cend(), std::is_sorted(in.begin(), in.end()));
  
      //an empty container
      Sequence<T> in0(0);
      invoke_on_all_policies(test_is_sorted(), in0.begin(), in0.end(), std::is_sorted(in0.begin(), in0.end()));
      invoke_on_all_policies(test_is_sorted(), in0.cbegin(), in0.cend(), std::is_sorted(in0.begin(), in0.end()));
  
      //non-descending order
      Sequence<T> in1(9, [](size_t) -> T { return T(0); });
      invoke_on_all_policies(test_is_sorted(), in1.begin(), in1.end(), std::is_sorted(in1.begin(), in1.end()));
      invoke_on_all_policies(test_is_sorted(), in1.cbegin(), in1.cend(), std::is_sorted(in1.begin(), in1.end()));
  }
  
  template <typename T>
  struct test_non_const
  {
      template <typename Policy, typename Iterator>
      void
      operator()(Policy&& exec, Iterator iter)
      {
          is_sorted(exec, iter, iter, std::less<T>());
          is_sorted_until(exec, iter, iter, std::less<T>());
      }
  };
  
  int
  main()
  {
  
      test_is_sorted_by_type<int32_t>();
      test_is_sorted_by_type<float64_t>();
  
      test_is_sorted_by_type<Wrapper<int32_t>>();
  
      test_algo_basic_single<int32_t>(run_for_rnd_fw<test_non_const<int32_t>>());
  
      std::cout << done() << std::endl;
      return 0;
  }
  