text: // -*- C++ -*-
  //===-- merge.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++98, c++03, c++11, c++14
  
  #include "support/pstl_test_config.h"
  
  #include <execution>
  #include <algorithm>
  #include <functional>
  
  #include "support/utils.h"
  
  using namespace TestUtils;
  
  struct test_merge
  {
      template <typename Policy, typename InputIterator1, typename InputIterator2, typename OutputIterator,
                typename Compare>
      void
      operator()(Policy&& exec, InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, InputIterator2 last2,
                 OutputIterator out_first, OutputIterator out_last, Compare comp)
      {
          using namespace std;
          {
              const auto res = merge(exec, first1, last1, first2, last2, out_first, comp);
              EXPECT_TRUE(res == out_last, "wrong return result from merge with predicate");
              EXPECT_TRUE(is_sorted(out_first, res, comp), "wrong result from merge with predicate");
              EXPECT_TRUE(includes(out_first, res, first1, last1, comp), "first sequence is not a part of result");
              EXPECT_TRUE(includes(out_first, res, first2, last2, comp), "second sequence is not a part of result");
          }
          {
              const auto res = merge(exec, first1, last1, first2, last2, out_first);
              EXPECT_TRUE(res == out_last, "wrong return result from merge");
              EXPECT_TRUE(is_sorted(out_first, res), "wrong result from merge");
          }
      }
  
      // for reverse iterators
      template <typename Policy, typename InputIterator1, typename InputIterator2, typename OutputIterator,
                typename Compare>
      void
      operator()(Policy&& exec, std::reverse_iterator<InputIterator1> first1, std::reverse_iterator<InputIterator1> last1,
                 std::reverse_iterator<InputIterator2> first2, std::reverse_iterator<InputIterator2> last2,
                 std::reverse_iterator<OutputIterator> out_first, std::reverse_iterator<OutputIterator> out_last, Compare)
      {
          using namespace std;
          typedef typename std::iterator_traits<std::reverse_iterator<InputIterator1>>::value_type T;
          const auto res = merge(exec, first1, last1, first2, last2, out_first, std::greater<T>());
  
          EXPECT_TRUE(res == out_last, "wrong return result from merge with predicate");
          EXPECT_TRUE(is_sorted(out_first, res, std::greater<T>()), "wrong result from merge with predicate");
          EXPECT_TRUE(includes(out_first, res, first1, last1, std::greater<T>()),
                      "first sequence is not a part of result");
          EXPECT_TRUE(includes(out_first, res, first2, last2, std::greater<T>()),
                      "second sequence is not a part of result");
      }
  };
  
  template <typename T, typename Generator1, typename Generator2>
  void
  test_merge_by_type(Generator1 generator1, Generator2 generator2)
  {
      using namespace std;
      size_t max_size = 100000;
      Sequence<T> in1(max_size, generator1);
      Sequence<T> in2(max_size / 2, generator2);
      Sequence<T> out(in1.size() + in2.size());
      std::sort(in1.begin(), in1.end());
      std::sort(in2.begin(), in2.end());
  
      for (size_t size = 0; size <= max_size; size = size <= 16 ? size + 1 : size_t(3.1415 * size))
      {
          invoke_on_all_policies(test_merge(), in1.cbegin(), in1.cbegin() + size, in2.data(), in2.data() + size / 2,
                                 out.begin(), out.begin() + 1.5 * size, std::less<T>());
          invoke_on_all_policies(test_merge(), in1.data(), in1.data() + size, in2.cbegin(), in2.cbegin() + size / 2,
                                 out.begin(), out.begin() + 3 * size / 2, std::less<T>());
      }
  }
  
  template <typename T>
  struct test_non_const
  {
      template <typename Policy, typename InputIterator, typename OutputIterator>
      void
      operator()(Policy&& exec, InputIterator input_iter, OutputIterator out_iter)
      {
          merge(exec, input_iter, input_iter, input_iter, input_iter, out_iter, non_const(std::less<T>()));
      }
  };
  
  int
  main()
  {
      test_merge_by_type<int32_t>([](size_t v) { return (v % 2 == 0 ? v : -v) * 3; }, [](size_t v) { return v * 2; });
      test_merge_by_type<float64_t>([](size_t v) { return float64_t(v); }, [](size_t v) { return float64_t(v - 100); });
  
  #if !_PSTL_ICC_16_17_TEST_64_TIMEOUT
      test_merge_by_type<Wrapper<int16_t>>([](size_t v) { return Wrapper<int16_t>(v % 100); },
                                           [](size_t v) { return Wrapper<int16_t>(v % 10); });
  #endif
  
      test_algo_basic_double<int32_t>(run_for_rnd_fw<test_non_const<int32_t>>());
  
      std::cout << done() << std::endl;
      return 0;
  }
  