text: // -*- C++ -*-
  //===-- fill.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_fill
  {
      template <typename It, typename T>
      bool
      check(It first, It last, const T& value)
      {
          for (; first != last; ++first)
              if (*first != value)
                  return false;
          return true;
      }
  
      template <typename Policy, typename Iterator, typename T>
      void
      operator()(Policy&& exec, Iterator first, Iterator last, const T& value)
      {
          fill(first, last, T(value + 1)); // initialize memory with different value
  
          fill(exec, first, last, value);
          EXPECT_TRUE(check(first, last, value), "fill wrong result");
      }
  };
  
  struct test_fill_n
  {
      template <typename It, typename Size, typename T>
      bool
      check(It first, Size n, const T& value)
      {
          for (Size i = 0; i < n; ++i, ++first)
              if (*first != value)
                  return false;
          return true;
      }
  
      template <typename Policy, typename Iterator, typename Size, typename T>
      void
      operator()(Policy&& exec, Iterator first, Size n, const T& value)
      {
          fill_n(first, n, T(value + 1)); // initialize memory with different value
  
          const Iterator one_past_last = fill_n(exec, first, n, value);
          const Iterator expected_return = std::next(first, n);
  
          EXPECT_TRUE(expected_return == one_past_last, "fill_n should return Iterator to one past the element assigned");
          EXPECT_TRUE(check(first, n, value), "fill_n wrong result");
  
          //n == -1
          const Iterator res = fill_n(exec, first, -1, value);
          EXPECT_TRUE(res == first, "fill_n wrong result for n == -1");
      }
  };
  
  template <typename T>
  void
  test_fill_by_type(std::size_t n)
  {
      Sequence<T> in(n, [](std::size_t) -> T { return T(0); }); //fill with zeros
      T value = -1;
  
      invoke_on_all_policies(test_fill(), in.begin(), in.end(), value);
      invoke_on_all_policies(test_fill_n(), in.begin(), n, value);
  }
  
  int
  main()
  {
  
      const std::size_t N = 100000;
  
      for (std::size_t n = 0; n < N; n = n < 16 ? n + 1 : size_t(3.1415 * n))
      {
          test_fill_by_type<int32_t>(n);
          test_fill_by_type<float64_t>(n);
      }
  
      std::cout << done() << std::endl;
  
      return 0;
  }
  