//===----------------------------------------------------------------------===//
//
// 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

// <unordered_set>

// class unordered_multiset

// template <class H2, class P2>
//   void merge(unordered_set<key_type, H2, P2, allocator_type>& source);
// template <class H2, class P2>
//   void merge(unordered_set<key_type, H2, P2, allocator_type>&& source);
// template <class H2, class P2>
//   void merge(unordered_multiset<key_type, H2, P2, allocator_type>& source);
// template <class H2, class P2>
//   void merge(unordered_multiset<key_type, H2, P2, allocator_type>&& source);

#include <unordered_set>
#include <cassert>
#include "test_macros.h"
#include "Counter.h"

template <class Set>
bool set_equal(const Set& set, Set other) {
  return set == other;
}

#ifndef TEST_HAS_NO_EXCEPTIONS
template <class T>
struct throw_hasher {
  bool& should_throw_;

  throw_hasher(bool& should_throw) : should_throw_(should_throw) {}

  std::size_t operator()(const T& p) const {
    if (should_throw_)
      throw 0;
    return std::hash<T>()(p);
  }
};
#endif

int main(int, char**) {
  {
    std::unordered_multiset<int> src{1, 3, 5};
    std::unordered_multiset<int> dst{2, 4, 5};
    dst.merge(src);
    assert(set_equal(src, {}));
    assert(set_equal(dst, {1, 2, 3, 4, 5, 5}));
  }

#ifndef TEST_HAS_NO_EXCEPTIONS
  {
    bool do_throw = false;
    typedef std::unordered_multiset<Counter<int>, throw_hasher<Counter<int>>> set_type;
    set_type src({1, 3, 5}, 0, throw_hasher<Counter<int>>(do_throw));
    set_type dst({2, 4, 5}, 0, throw_hasher<Counter<int>>(do_throw));

    assert(Counter_base::gConstructed == 6);

    do_throw = true;
    try {
      dst.merge(src);
    } catch (int) {
      do_throw = false;
    }
    assert(!do_throw);
    assert(set_equal(src, set_type({1, 3, 5}, 0, throw_hasher<Counter<int>>(do_throw))));
    assert(set_equal(dst, set_type({2, 4, 5}, 0, throw_hasher<Counter<int>>(do_throw))));
  }
#endif
  assert(Counter_base::gConstructed == 0);
  struct equal {
    equal() = default;

    bool operator()(const Counter<int>& lhs, const Counter<int>& rhs) const { return lhs == rhs; }
  };
  struct hasher {
    hasher() = default;
    std::size_t operator()(const Counter<int>& p) const { return std::hash<Counter<int>>()(p); }
  };
  {
    typedef std::unordered_multiset<Counter<int>, std::hash<Counter<int>>, std::equal_to<Counter<int>>> first_set_type;
    typedef std::unordered_multiset<Counter<int>, hasher, equal> second_set_type;
    typedef std::unordered_set<Counter<int>, hasher, equal> third_set_type;

    {
      first_set_type first{1, 2, 3};
      second_set_type second{2, 3, 4};
      third_set_type third{1, 3};

      assert(Counter_base::gConstructed == 8);

      first.merge(second);
      first.merge(third);

      assert(set_equal(first, {1, 2, 3, 4, 2, 3, 1, 3}));
      assert(set_equal(second, {}));
      assert(set_equal(third, {}));

      assert(Counter_base::gConstructed == 8);
    }
    assert(Counter_base::gConstructed == 0);
    {
      first_set_type first{1, 2, 3};
      second_set_type second{2, 3, 4};
      third_set_type third{1, 3};

      assert(Counter_base::gConstructed == 8);

      first.merge(std::move(second));
      first.merge(std::move(third));

      assert(set_equal(first, {1, 2, 3, 4, 2, 3, 1, 3}));
      assert(set_equal(second, {}));
      assert(set_equal(third, {}));

      assert(Counter_base::gConstructed == 8);
    }
    assert(Counter_base::gConstructed == 0);
  }
  {
    std::unordered_multiset<int> first;
    {
      std::unordered_multiset<int> second;
      first.merge(second);
      first.merge(std::move(second));
    }
    {
      std::unordered_set<int> second;
      first.merge(second);
      first.merge(std::move(second));
    }
  }
  return 0;
}