//===----------------------------------------------------------------------===//
//
// 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 "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;
}
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