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

// <unordered_set>

// template <class Value, class Hash = hash<Value>, class Pred = equal_to<Value>,
//           class Alloc = allocator<Value>>
// class unordered_multiset

// void reserve(size_type n);

#include <unordered_set>
#include <cassert>

#include "test_macros.h"
#include "min_allocator.h"

template <class C>
void test(const C& c) {
  assert(c.size() == 6);
  assert(c.count(1) == 2);
  assert(c.count(2) == 2);
  assert(c.count(3) == 1);
  assert(c.count(4) == 1);
}

void reserve_invariant(std::size_t n) // LWG #2156
{
  for (std::size_t i = 0; i < n; ++i) {
    std::unordered_multiset<std::size_t> c;
    c.reserve(n);
    std::size_t buckets = c.bucket_count();
    for (std::size_t j = 0; j < i; ++j) {
      c.insert(i);
      assert(buckets == c.bucket_count());
    }
  }
}

int main(int, char**) {
  {
    typedef std::unordered_multiset<int> C;
    typedef int P;
    P a[] = {P(1), P(2), P(3), P(4), P(1), P(2)};
    C c(a, a + sizeof(a) / sizeof(a[0]));
    test(c);
    assert(c.bucket_count() >= 7);
    c.reserve(3);
    LIBCPP_ASSERT(c.bucket_count() == 7);
    test(c);
    c.max_load_factor(2);
    c.reserve(3);
    LIBCPP_ASSERT(c.bucket_count() == 3);
    test(c);
    c.reserve(31);
    assert(c.bucket_count() >= 16);
    test(c);
  }
#if TEST_STD_VER >= 11
  {
    typedef std::unordered_multiset<int, std::hash<int>, std::equal_to<int>, min_allocator<int>> C;
    typedef int P;
    P a[] = {P(1), P(2), P(3), P(4), P(1), P(2)};
    C c(a, a + sizeof(a) / sizeof(a[0]));
    test(c);
    assert(c.bucket_count() >= 7);
    c.reserve(3);
    LIBCPP_ASSERT(c.bucket_count() == 7);
    test(c);
    c.max_load_factor(2);
    c.reserve(3);
    LIBCPP_ASSERT(c.bucket_count() == 3);
    test(c);
    c.reserve(31);
    assert(c.bucket_count() >= 16);
    test(c);
  }
#endif
  reserve_invariant(20);

  return 0;
}
