//===----------------------------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
// <algorithm>
// UNSUPPORTED: c++03, c++11, c++14, c++17
// template<forward_iterator I, sentinel_for<I> S, class Proj = identity,
// indirect_strict_weak_order<projected<I, Proj>> Comp = ranges::less>
// constexpr ranges::minmax_element_result<I> ranges::minmax_element(I first, S last, Comp comp = {}, Proj proj = {});
//
// template<forward_range R, class Proj = identity,
// indirect_strict_weak_order<projected<iterator_t<R>, Proj>> Comp = ranges::less>
// constexpr ranges::minmax_element_result<borrowed_iterator_t<R>>
// ranges::minmax_element(R&& r, Comp comp = {}, Proj proj = {});
#include <algorithm>
#include <array>
#include <cassert>
#include <functional>
#include <ranges>
#include "almost_satisfies_types.h"
#include "test_iterators.h"
template <class T>
concept HasMinMaxElementR = requires(T t) { std::ranges::minmax_element(t); };
struct NoLessThanOp {};
struct NotTotallyOrdered {
int i;
bool operator<(const NotTotallyOrdered& o) const { return i < o.i; }
};
static_assert(HasMinMaxElementR<int (&)[10]>); // make sure HasMinMaxElementR works with an array
static_assert(!HasMinMaxElementR<NoLessThanOp (&)[10]>);
static_assert(!HasMinMaxElementR<NotTotallyOrdered (&)[10]>);
static_assert(HasMinMaxElementR<std::initializer_list<int>>); // make sure HasMinMaxElementR works with an initializer_list
static_assert(!HasMinMaxElementR<std::initializer_list<NoLessThanOp>>);
static_assert(!HasMinMaxElementR<std::initializer_list<NotTotallyOrdered>>);
static_assert(!HasMinMaxElementR<InputRangeNotDerivedFrom>);
static_assert(!HasMinMaxElementR<InputRangeNotIndirectlyReadable>);
static_assert(!HasMinMaxElementR<InputRangeNotInputOrOutputIterator>);
static_assert(!HasMinMaxElementR<InputRangeNotSentinelSemiregular>);
static_assert(!HasMinMaxElementR<InputRangeNotSentinelEqualityComparableWith>);
template <class It, class Sent = sentinel_wrapper<It>>
concept HasMinMaxElementIt = requires(It it, Sent sent) { std::ranges::minmax_element(it, sent); };
static_assert(HasMinMaxElementIt<int*>); // make sure HasMinMaxElementIt works
static_assert(!HasMinMaxElementIt<InputIteratorNotDerivedFrom>);
static_assert(!HasMinMaxElementIt<InputIteratorNotIndirectlyReadable>);
static_assert(!HasMinMaxElementIt<InputIteratorNotInputOrOutputIterator>);
static_assert(!HasMinMaxElementIt<int*, SentinelForNotSemiregular>);
static_assert(!HasMinMaxElementIt<int*, SentinelForNotWeaklyEqualityComparableWith>);
static_assert(std::is_same_v<std::ranges::minmax_element_result<int>, std::ranges::min_max_result<int>>);
template <class It>
constexpr void test_iterators(std::initializer_list<int> a, int expectedMin, int expectedMax) {
using Expected = std::ranges::minmax_element_result<It>;
const int* first = a.begin();
const int* last = a.end();
{
std::same_as<Expected> auto it = std::ranges::minmax_element(It(first), It(last));
assert(base(it.min) == first + expectedMin);
assert(base(it.max) == first + expectedMax);
}
{
using Sent = sentinel_wrapper<It>;
std::same_as<Expected> auto it = std::ranges::minmax_element(It(first), Sent(It(last)));
assert(base(it.min) == first + expectedMin);
assert(base(it.max) == first + expectedMax);
}
{
auto range = std::ranges::subrange(It(first), It(last));
std::same_as<Expected> auto it = std::ranges::minmax_element(range);
assert(base(it.min) == first + expectedMin);
assert(base(it.max) == first + expectedMax);
}
{
using Sent = sentinel_wrapper<It>;
auto range = std::ranges::subrange(It(first), Sent(It(last)));
std::same_as<Expected> auto it = std::ranges::minmax_element(range);
assert(base(it.min) == first + expectedMin);
assert(base(it.max) == first + expectedMax);
}
}
template <class It>
constexpr bool test_iterators() {
test_iterators<It>({}, 0, 0);
test_iterators<It>({1}, 0, 0);
test_iterators<It>({1, 2}, 0, 1);
test_iterators<It>({2, 1}, 1, 0);
test_iterators<It>({2, 1, 2}, 1, 2);
test_iterators<It>({2, 1, 1}, 1, 0);
test_iterators<It>({2, 2, 1}, 2, 1);
return true;
}
constexpr void test_borrowed_range_and_sentinel() {
int a[] = {7, 6, 1, 3, 5, 1, 2, 4};
std::ranges::minmax_element_result<int*> ret = std::ranges::minmax_element(std::views::all(a));
assert(ret.min == a + 2);
assert(ret.max == a + 0);
assert(*ret.min == 1);
assert(*ret.max == 7);
}
constexpr void test_comparator() {
int a[] = {7, 6, 9, 3, 5, 1, 2, 4};
std::ranges::minmax_element_result<int*> ret = std::ranges::minmax_element(a, std::ranges::greater{});
assert(ret.min == a + 2);
assert(ret.max == a + 5);
assert(*ret.min == 9);
assert(*ret.max == 1);
}
constexpr void test_projection() {
{
int a[] = {7, 6, 9, 3, 5, 1, 2, 4};
std::ranges::minmax_element_result<int*> ret =
std::ranges::minmax_element(a, std::ranges::less{}, [](int i) { return i == 5 ? -100 : i; });
assert(ret.min == a + 4);
assert(ret.max == a + 2);
assert(*ret.min == 5);
assert(*ret.max == 9);
}
{
int a[] = {7, 6, 9, 3, 5, 1, 2, 4};
std::ranges::minmax_element_result<int*> ret =
std::ranges::minmax_element(a, std::less<int*>{}, [](int& i) { return &i; });
assert(ret.min == a + 0);
assert(ret.max == a + 7);
assert(*ret.min == 7);
assert(*ret.max == 4);
}
}
struct Immobile {
int i;
constexpr Immobile(int i_) : i(i_) {}
Immobile(const Immobile&) = delete;
Immobile(Immobile&&) = delete;
auto operator<=>(const Immobile&) const = default;
};
constexpr void test_immobile() {
{
Immobile arr[]{1, 2, 3};
auto ret = std::ranges::minmax_element(arr);
assert(ret.min == arr + 0);
assert(ret.max == arr + 2);
}
{
Immobile arr[]{1, 2, 3};
auto ret = std::ranges::minmax_element(arr, arr + 3);
assert(ret.min == arr + 0);
assert(ret.max == arr + 2);
}
}
constexpr void test_dangling() {
int compares = 0;
int projections = 0;
auto comparator = [&](int a, int b) {
++compares;
return a < b;
};
auto projection = [&](int a) {
++projections;
return a;
};
[[maybe_unused]] std::same_as<std::ranges::minmax_element_result<std::ranges::dangling>> auto ret =
std::ranges::minmax_element(std::array{1, 2, 3}, comparator, projection);
assert(compares == 3);
assert(projections == 6);
}
constexpr bool test() {
test_iterators<forward_iterator<const int*>>();
test_iterators<bidirectional_iterator<const int*>>();
test_iterators<random_access_iterator<const int*>>();
test_iterators<contiguous_iterator<const int*>>();
test_iterators<const int*>();
test_iterators<int*>();
test_borrowed_range_and_sentinel();
test_comparator();
test_projection();
test_dangling();
{ // check that std::invoke is used
{
struct S {
int i;
};
S b[3] = {S{2}, S{1}, S{3}};
std::same_as<std::ranges::minmax_element_result<S*>> auto ret = std::ranges::minmax_element(b, {}, &S::i);
assert(ret.min->i == 1);
assert(ret.max->i == 3);
assert(ret.min == b + 1);
assert(ret.max == b + 2);
}
{
struct S {
int i;
};
S b[3] = {S{2}, S{1}, S{3}};
std::same_as<std::ranges::minmax_element_result<S*>> auto ret = std::ranges::minmax_element(b, b + 3, {}, &S::i);
assert(ret.min->i == 1);
assert(ret.max->i == 3);
assert(ret.min == b + 1);
assert(ret.max == b + 2);
}
}
{ // check that the leftmost value for min an rightmost for max are returned
{
struct S {
int comp;
int other;
};
S a[] = { {0, 0}, {0, 2}, {0, 1} };
auto ret = std::ranges::minmax_element(a, a + 3, {}, &S::comp);
assert(ret.min->comp == 0);
assert(ret.max->comp == 0);
assert(ret.min->other == 0);
assert(ret.max->other == 1);
}
{
struct S {
int comp;
int other;
};
S a[] = { {0, 0}, {0, 2}, {0, 1} };
auto ret = std::ranges::minmax_element(a, {}, &S::comp);
assert(ret.min->comp == 0);
assert(ret.max->comp == 0);
assert(ret.min->other == 0);
assert(ret.max->other == 1);
}
}
{ // check that an empty range works
{
std::array<int, 0> a = {};
auto ret = std::ranges::minmax_element(a.begin(), a.end());
assert(ret.min == a.begin());
assert(ret.max == a.begin());
}
{
std::array<int, 0> a = {};
auto ret = std::ranges::minmax_element(a);
assert(ret.min == a.begin());
assert(ret.max == a.begin());
}
}
{ // check in ascending order
{
int a[] = {1, 2, 3};
auto ret = std::ranges::minmax_element(a, a + 3);
assert(ret.min == a + 0);
assert(ret.max == a + 2);
assert(*ret.min == 1);
assert(*ret.max == 3);
}
{
int a[] = {1, 2, 3};
auto ret = std::ranges::minmax_element(a);
assert(ret.min == a + 0);
assert(ret.max == a + 2);
assert(*ret.min == 1);
assert(*ret.max == 3);
}
}
{ // check in descending order
{
int a[] = {3, 2, 1};
auto ret = std::ranges::minmax_element(a, a + 3);
assert(ret.min == a + 2);
assert(ret.max == a + 0);
assert(*ret.min == 1);
assert(*ret.max == 3);
}
{
int a[] = {3, 2, 1};
auto ret = std::ranges::minmax_element(a);
assert(ret.min == a + 2);
assert(ret.max == a + 0);
assert(*ret.min == 1);
assert(*ret.max == 3);
}
}
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
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