text: // -*- C++ -*-
  //===-- swap_ranges.pass.cpp ----------------------------------------------===//
  //
  // Copyright (C) 2017-2020 Intel Corporation
  //
  // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
  //
  // This file incorporates work covered by the following copyright and permission
  // notice:
  //
  // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
  // See https://llvm.org/LICENSE.txt for license information.
  //
  //===----------------------------------------------------------------------===//
  
  #include "support/pstl_test_config.h"
  #include "support/utils.h"
  
  #include _PSTL_TEST_HEADER(execution)
  #include _PSTL_TEST_HEADER(algorithm)
  
  #include <iterator>
  #include <numeric>
  
  using namespace TestUtils;
  
  template <typename T>
  struct wrapper
  {
      T t;
      ::std::size_t number_of_swaps = 0;
      wrapper(): t() {}
      explicit wrapper(T t_) : t(t_) {}
      template <typename U>
      void
      operator=(const U& b)
      {
          t = b;
      }
      bool
      operator==(const wrapper<T>& a) const
      {
          return t == a.t;
      }
  };
  
  template <typename T>
  void
  swap(wrapper<T>& a, wrapper<T>& b)
  {
      ::std::swap(a.t, b.t);
      a.number_of_swaps++;
      b.number_of_swaps++;
  }
  
  template <typename T>
  struct check_swap
  {
      bool
      operator()(T& a)
      {
          return true;
      }
  };
  
  template <typename T>
  struct check_swap<wrapper<T>>
  {
      bool
      operator()(wrapper<T>& a)
      {
          bool temp = (a.number_of_swaps == 1);
          a.number_of_swaps = 0;
          return temp;
      }
  };
  
  template <typename Type>
  struct test_one_policy
  {
      template <typename ExecutionPolicy, typename Iterator1, typename Iterator2>
      void
      operator()(ExecutionPolicy&& exec, Iterator1 data_b, Iterator1 data_e, Iterator2 actual_b, Iterator2 actual_e)
      {
          using namespace std;
          using T_ref = typename iterator_traits<Iterator1>::reference;
          using T = typename iterator_traits<Iterator1>::value_type;
  
          iota(data_b, data_e, 0);
          iota(actual_b, actual_e, ::std::distance(data_b, data_e));
  
          Iterator2 actual_return = swap_ranges(exec, data_b, data_e, actual_b);
          bool check_return = (actual_return == actual_e);
          EXPECT_TRUE(check_return, "wrong result of swap_ranges");
          if (check_return)
          {
              ::std::size_t i = 0;
              bool check = all_of(actual_b, actual_e, [&i](T_ref a) { return a == T(i++); }) &&
                           all_of(data_b, data_e, [&i](T_ref a) { return a == T(i++); });
  
              EXPECT_TRUE(check, "wrong effect of swap_ranges");
  
              if (check)
              {
                  bool swap_check =
                      all_of(data_b, data_e, check_swap<T>()) && all_of(actual_b, actual_e, check_swap<T>());
                  EXPECT_TRUE(swap_check, "wrong effect of swap_ranges swap check");
              }
          }
      }
  };
  
  template <typename T>
  void
  test()
  {
      const ::std::size_t max_len = 100000;
  
      Sequence<T> data(max_len);
      Sequence<T> actual(max_len);
  
      for (::std::size_t len = 0; len < max_len; len = len <= 16 ? len + 1 : ::std::size_t(3.1415 * len))
      {
          invoke_on_all_policies<>()(test_one_policy<T>(), data.begin(), data.begin() + len, actual.begin(),
                                     actual.begin() + len);
      }
  }
  
  int
  main()
  {
      test<wrapper<uint16_t>>();
      test<wrapper<float64_t>>();
      test<int32_t>();
      test<float32_t>();
  
      ::std::cout << done() << ::std::endl;
      return 0;
  }
  