| //===----------------------------------------------------------------------===// |
| // |
| // 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, c++17 |
| |
| // <algorithm> |
| |
| // template<random_access_iterator I, sentinel_for<I> S, class Comp = ranges::less, |
| // class Proj = identity> |
| // requires sortable<I, Comp, Proj> |
| // constexpr I |
| // ranges::partial_sort(I first, I middle, S last, Comp comp = {}, Proj proj = {}); // since C++20 |
| // |
| // template<random_access_range R, class Comp = ranges::less, class Proj = identity> |
| // requires sortable<iterator_t<R>, Comp, Proj> |
| // constexpr borrowed_iterator_t<R> |
| // ranges::partial_sort(R&& r, iterator_t<R> middle, Comp comp = {}, Proj proj = {}); // since C++20 |
| |
| #include <algorithm> |
| #include <array> |
| #include <concepts> |
| #include <functional> |
| #include <ranges> |
| |
| #include "almost_satisfies_types.h" |
| #include "boolean_testable.h" |
| #include "test_iterators.h" |
| |
| // SFINAE tests. |
| |
| using BadComparator = ComparatorNotCopyable<int*>; |
| static_assert(!std::sortable<int*, BadComparator>); |
| |
| template <class Iter, class Sent = sentinel_wrapper<Iter>, class Comp = std::ranges::less> |
| concept HasPartialSortIt = requires(Iter first, Iter mid, Sent last, Comp comp) { |
| std::ranges::partial_sort(first, mid, last, comp); |
| }; |
| |
| static_assert(HasPartialSortIt<int*>); |
| static_assert(!HasPartialSortIt<RandomAccessIteratorNotDerivedFrom>); |
| static_assert(!HasPartialSortIt<RandomAccessIteratorBadIndex>); |
| static_assert(!HasPartialSortIt<int*, SentinelForNotSemiregular>); |
| static_assert(!HasPartialSortIt<int*, SentinelForNotWeaklyEqualityComparableWith>); |
| static_assert(!HasPartialSortIt<int*, int*, BadComparator>); |
| static_assert(!HasPartialSortIt<const int*>); // Doesn't satisfy `sortable`. |
| |
| template <class Range, class Comp = std::ranges::less> |
| concept HasPartialSortR = requires(Range range, std::ranges::iterator_t<Range> mid, Comp comp) { |
| std::ranges::partial_sort(range, mid, comp); |
| }; |
| |
| static_assert(HasPartialSortR<UncheckedRange<int*>>); |
| static_assert(!HasPartialSortR<RandomAccessRangeNotDerivedFrom>); |
| static_assert(!HasPartialSortR<RandomAccessRangeBadIndex>); |
| static_assert(!HasPartialSortR<UncheckedRange<int*, SentinelForNotSemiregular>>); |
| static_assert(!HasPartialSortR<UncheckedRange<int*, SentinelForNotWeaklyEqualityComparableWith>>); |
| static_assert(!HasPartialSortR<UncheckedRange<int*>, BadComparator>); |
| static_assert(!HasPartialSortR<UncheckedRange<const int*>>); // Doesn't satisfy `sortable`. |
| |
| template <class Iter, class Sent, std::size_t N> |
| constexpr void test_one(std::array<int, N> input, std::size_t mid_index, std::array<int, N> sorted) { |
| { // (iterator, sentinel) overload. |
| auto partially_sorted = input; |
| auto begin = Iter(partially_sorted.data()); |
| auto mid = begin + mid_index; |
| auto end = Sent(Iter(partially_sorted.data() + partially_sorted.size())); |
| |
| std::same_as<Iter> decltype(auto) last = std::ranges::partial_sort(begin, mid, end); |
| assert(std::equal(partially_sorted.begin(), partially_sorted.begin() + mid_index, |
| sorted.begin(), sorted.begin() + mid_index)); |
| assert(base(last) == partially_sorted.data() + partially_sorted.size()); |
| } |
| |
| { // (range) overload. |
| auto partially_sorted = input; |
| auto begin = Iter(partially_sorted.data()); |
| auto mid = begin + mid_index; |
| auto end = Sent(Iter(partially_sorted.data() + partially_sorted.size())); |
| auto range = std::ranges::subrange(begin, end); |
| |
| std::same_as<Iter> decltype(auto) last = std::ranges::partial_sort(range, mid); |
| assert(std::ranges::equal(begin, begin + mid_index, sorted.begin(), sorted.begin() + mid_index)); |
| assert(base(last) == partially_sorted.data() + partially_sorted.size()); |
| } |
| } |
| |
| template <class Iter, class Sent, std::size_t N> |
| constexpr void test_all_subsequences(std::array<int, N> input) { |
| auto sorted = input; |
| std::sort(sorted.begin(), sorted.end()); |
| |
| for (std::size_t n = 0; n <= N; ++n) { |
| test_one<Iter, Sent, N>(input, n, sorted); |
| } |
| } |
| |
| template <class Iter, class Sent> |
| constexpr void test_iterator_and_sentinel() { |
| // Empty sequence. |
| test_one<Iter, Sent, 0>({}, 0, {}); |
| |
| // 1-element sequence. |
| test_all_subsequences<Iter, Sent>(std::array{1}); |
| |
| // 2-element sequence. |
| test_all_subsequences<Iter, Sent>(std::array{2, 1}); |
| |
| // 3-element sequence. |
| test_all_subsequences<Iter, Sent>(std::array{2, 1, 3}); |
| |
| // Longer sequence. |
| test_all_subsequences<Iter, Sent>(std::array{2, 1, 3, 6, 8, 4, 11, 5}); |
| |
| // Longer sequence with duplicates. |
| test_all_subsequences<Iter, Sent>(std::array{2, 1, 3, 6, 2, 8, 6}); |
| |
| // All elements are the same. |
| test_all_subsequences<Iter, Sent>(std::array{1, 1, 1}); |
| |
| // Already sorted. |
| test_all_subsequences<Iter, Sent>(std::array{1, 2, 3, 4, 5}); |
| |
| // Descending. |
| test_all_subsequences<Iter, Sent>(std::array{5, 4, 3, 2, 1}); |
| |
| // Repeating pattern. |
| test_all_subsequences<Iter, Sent>(std::array{1, 2, 1, 2, 1, 2}); |
| } |
| |
| constexpr void test_iterators() { |
| test_iterator_and_sentinel<random_access_iterator<int*>, random_access_iterator<int*>>(); |
| test_iterator_and_sentinel<random_access_iterator<int*>, sentinel_wrapper<random_access_iterator<int*>>>(); |
| test_iterator_and_sentinel<contiguous_iterator<int*>, contiguous_iterator<int*>>(); |
| test_iterator_and_sentinel<contiguous_iterator<int*>, sentinel_wrapper<contiguous_iterator<int*>>>(); |
| test_iterator_and_sentinel<int*, int*>(); |
| test_iterator_and_sentinel<int*, sentinel_wrapper<int*>>(); |
| } |
| |
| constexpr bool test() { |
| test_iterators(); |
| |
| { // A custom comparator works. |
| const std::array orig_in = {1, 2, 3, 4, 5}; |
| |
| { |
| auto in = orig_in; |
| auto b = in.begin(); |
| auto m = b + 2; |
| |
| auto last = std::ranges::partial_sort(b, m, in.end(), std::ranges::greater{}); |
| assert(std::ranges::equal(std::ranges::subrange(b, m), std::array{5, 4})); |
| assert(last == in.end()); |
| } |
| |
| { |
| auto in = orig_in; |
| auto b = in.begin(); |
| auto m = b + 2; |
| |
| auto last = std::ranges::partial_sort(in, m, std::ranges::greater{}); |
| assert(std::ranges::equal(std::ranges::subrange(b, m), std::array{5, 4})); |
| assert(last == in.end()); |
| } |
| } |
| |
| { // A custom projection works. |
| struct A { |
| int a; |
| constexpr bool operator==(const A&) const = default; |
| }; |
| |
| const std::array orig_in = {A{2}, A{3}, A{1}}; |
| |
| { |
| auto in = orig_in; |
| auto b = in.begin(); |
| auto m = b + 2; |
| |
| auto last = std::ranges::partial_sort(b, m, in.end(), {}, &A::a); |
| assert(std::ranges::equal( |
| std::ranges::subrange(b, m), std::array{A{1}, A{2}} |
| )); |
| assert(last == in.end()); |
| } |
| |
| { |
| auto in = orig_in; |
| auto b = in.begin(); |
| auto m = b + 2; |
| |
| auto last = std::ranges::partial_sort(in, m, {}, &A::a); |
| assert(std::ranges::equal( |
| std::ranges::subrange(b, m), std::array{A{1}, A{2}} |
| )); |
| assert(last == in.end()); |
| } |
| } |
| |
| return true; |
| } |
| |
| int main(int, char**) { |
| test(); |
| static_assert(test()); |
| |
| return 0; |
| } |