//===----------------------------------------------------------------------===//
//
// 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 rehash(size_type n);

#include <unordered_set>
#include <cassert>

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

template <class C>
void rehash_postcondition(const C& c, std::size_t n) {
  assert(c.bucket_count() >= c.size() / c.max_load_factor() && c.bucket_count() >= n);
}

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);
}

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.rehash(3);
    rehash_postcondition(c, 3);
    LIBCPP_ASSERT(c.bucket_count() == 7);
    test(c);
    c.max_load_factor(2);
    c.rehash(3);
    rehash_postcondition(c, 3);
    LIBCPP_ASSERT(c.bucket_count() == 3);
    test(c);
    c.rehash(31);
    rehash_postcondition(c, 31);
    LIBCPP_ASSERT(c.bucket_count() == 31);
    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.rehash(3);
    rehash_postcondition(c, 3);
    LIBCPP_ASSERT(c.bucket_count() == 7);
    test(c);
    c.max_load_factor(2);
    c.rehash(3);
    rehash_postcondition(c, 3);
    LIBCPP_ASSERT(c.bucket_count() == 3);
    test(c);
    c.rehash(31);
    rehash_postcondition(c, 31);
    LIBCPP_ASSERT(c.bucket_count() == 31);
    test(c);
  }
#endif

  return 0;
}
