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

// <forward_list>

// void unique();      // C++17 and before
// size_type unique(); // C++20 and after

#include <forward_list>
#include <iterator>
#include <cassert>

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

template <class L>
void do_unique(L &l, typename L::size_type expected)
{
    typename L::size_type old_size = std::distance(l.begin(), l.end());
#if TEST_STD_VER > 17
    ASSERT_SAME_TYPE(decltype(l.unique()), typename L::size_type);
    assert(l.unique() == expected);
#else
    ASSERT_SAME_TYPE(decltype(l.unique()), void);
    l.unique();
#endif
    assert(old_size - std::distance(l.begin(), l.end()) == expected);
}

int main(int, char**)
{
    {
        typedef int T;
        typedef std::forward_list<T> C;
        const T t1[] = {0, 5, 5, 0, 0, 0, 5};
        const T t2[] = {0, 5, 0, 5};
        C c1(std::begin(t1), std::end(t1));
        C c2(std::begin(t2), std::end(t2));
        do_unique(c1, 3);
        assert(c1 == c2);
    }
    {
        typedef int T;
        typedef std::forward_list<T> C;
        const T t1[] = {0, 0, 0, 0};
        const T t2[] = {0};
        C c1(std::begin(t1), std::end(t1));
        C c2(std::begin(t2), std::end(t2));
        do_unique(c1, 3);
        assert(c1 == c2);
    }
    {
        typedef int T;
        typedef std::forward_list<T> C;
        const T t1[] = {5, 5, 5};
        const T t2[] = {5};
        C c1(std::begin(t1), std::end(t1));
        C c2(std::begin(t2), std::end(t2));
        do_unique(c1, 2);
        assert(c1 == c2);
    }
    {
        typedef int T;
        typedef std::forward_list<T> C;
        C c1;
        C c2;
        do_unique(c1, 0);
        assert(c1 == c2);
    }
    {
        typedef int T;
        typedef std::forward_list<T> C;
        const T t1[] = {5, 5, 5, 0};
        const T t2[] = {5, 0};
        C c1(std::begin(t1), std::end(t1));
        C c2(std::begin(t2), std::end(t2));
        do_unique(c1, 2);
        assert(c1 == c2);
    }
#if TEST_STD_VER >= 11
    {
        typedef int T;
        typedef std::forward_list<T, min_allocator<T>> C;
        const T t1[] = {0, 5, 5, 0, 0, 0, 5};
        const T t2[] = {0, 5, 0, 5};
        C c1(std::begin(t1), std::end(t1));
        C c2(std::begin(t2), std::end(t2));
        do_unique(c1, 3);
        assert(c1 == c2);
    }
    {
        typedef int T;
        typedef std::forward_list<T, min_allocator<T>> C;
        const T t1[] = {0, 0, 0, 0};
        const T t2[] = {0};
        C c1(std::begin(t1), std::end(t1));
        C c2(std::begin(t2), std::end(t2));
        do_unique(c1, 3);
        assert(c1 == c2);
    }
    {
        typedef int T;
        typedef std::forward_list<T, min_allocator<T>> C;
        const T t1[] = {5, 5, 5};
        const T t2[] = {5};
        C c1(std::begin(t1), std::end(t1));
        C c2(std::begin(t2), std::end(t2));
        do_unique(c1, 2);
        assert(c1 == c2);
    }
    {
        typedef int T;
        typedef std::forward_list<T, min_allocator<T>> C;
        C c1;
        C c2;
        do_unique(c1, 0);
        assert(c1 == c2);
    }
    {
        typedef int T;
        typedef std::forward_list<T, min_allocator<T>> C;
        const T t1[] = {5, 5, 5, 0};
        const T t2[] = {5, 0};
        C c1(std::begin(t1), std::end(t1));
        C c2(std::begin(t2), std::end(t2));
        do_unique(c1, 2);
        assert(c1 == c2);
    }
#endif

  return 0;
}