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//===----------------------------------------------------------------------===//
//
// 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
// UNSUPPORTED: libcpp-has-no-incomplete-ranges
// template<input_iterator I, sentinel_for<I> S, class T, class Proj = identity>
// requires indirect_binary_predicate<ranges::equal_to, projected<I, Proj>, const T*>
// constexpr iter_difference_t<I>
// ranges::count(I first, S last, const T& value, Proj proj = {});
// template<input_range R, class T, class Proj = identity>
// requires indirect_binary_predicate<ranges::equal_to, projected<iterator_t<R>, Proj>, const T*>
// constexpr range_difference_t<R>
// ranges::count(R&& r, const T& value, Proj proj = {});
#include <algorithm>
#include <array>
#include <cassert>
#include <ranges>
#include "almost_satisfies_types.h"
#include "test_iterators.h"
struct NotEqualityComparable {
bool operator==(NotEqualityComparable&&) const;
bool operator==(NotEqualityComparable&) const;
bool operator==(const NotEqualityComparable&&) const;
};
template <class It, class Sent = It>
concept HasCountIt = requires(It it, Sent sent) { std::ranges::count(it, sent, *it); };
static_assert(HasCountIt<int*>);
static_assert(!HasCountIt<NotEqualityComparable*>);
static_assert(!HasCountIt<InputIteratorNotDerivedFrom>);
static_assert(!HasCountIt<InputIteratorNotIndirectlyReadable>);
static_assert(!HasCountIt<InputIteratorNotInputOrOutputIterator>);
static_assert(!HasCountIt<cpp20_input_iterator<int*>, SentinelForNotSemiregular>);
static_assert(!HasCountIt<cpp20_input_iterator<int*>, InputRangeNotSentinelEqualityComparableWith>);
static_assert(!HasCountIt<int*, int>);
static_assert(!HasCountIt<int, int*>);
template <class Range, class ValT>
concept HasCountR = requires(Range r) { std::ranges::count(r, ValT{}); };
static_assert(HasCountR<std::array<int, 1>, int>);
static_assert(!HasCountR<int, int>);
static_assert(!HasCountR<std::array<NotEqualityComparable, 1>, NotEqualityComparable>);
static_assert(!HasCountR<InputRangeNotDerivedFrom, int>);
static_assert(!HasCountR<InputRangeNotIndirectlyReadable, int>);
static_assert(!HasCountR<InputRangeNotInputOrOutputIterator, int>);
static_assert(!HasCountR<InputRangeNotSentinelSemiregular, int>);
static_assert(!HasCountR<InputRangeNotSentinelEqualityComparableWith, int>);
template <class It, class Sent = It>
constexpr void test_iterators() {
{
// simple test
{
int a[] = {1, 2, 3, 4};
std::same_as<std::ptrdiff_t> auto ret = std::ranges::count(It(a), Sent(It(a + 4)), 3);
assert(ret == 1);
}
{
int a[] = {1, 2, 3, 4};
auto range = std::ranges::subrange(It(a), Sent(It(a + 4)));
std::same_as<std::ptrdiff_t> auto ret = std::ranges::count(range, 3);
assert(ret == 1);
}
}
{
// check that an empty range works
{
std::array<int, 0> a = {};
auto ret = std::ranges::count(It(a.data()), Sent(It(a.data() + a.size())), 1);
assert(ret == 0);
}
{
std::array<int, 0> a = {};
auto range = std::ranges::subrange(It(a.data()), Sent(It(a.data() + a.size())));
auto ret = std::ranges::count(range, 1);
assert(ret == 0);
}
}
{
// check that a range with a single element works
{
std::array a = {2};
auto ret = std::ranges::count(It(a.data()), Sent(It(a.data() + a.size())), 2);
assert(ret == 1);
}
{
std::array a = {2};
auto range = std::ranges::subrange(It(a.data()), Sent(It(a.data() + a.size())));
auto ret = std::ranges::count(range, 2);
assert(ret == 1);
}
}
{
// check that 0 is returned with no match
{
std::array a = {1, 1, 1};
auto ret = std::ranges::count(It(a.data()), Sent(It(a.data() + a.size())), 0);
assert(ret == 0);
}
{
std::array a = {1, 1, 1};
auto range = std::ranges::subrange(It(a.data()), Sent(It(a.data() + a.size())));
auto ret = std::ranges::count(range, 0);
assert(ret == 0);
}
}
{
// check that more than one element is counted
{
std::array a = {3, 3, 4, 3, 3};
auto ret = std::ranges::count(It(a.data()), Sent(It(a.data() + a.size())), 3);
assert(ret == 4);
}
{
std::array a = {3, 3, 4, 3, 3};
auto range = std::ranges::subrange(It(a.data()), Sent(It(a.data() + a.size())));
auto ret = std::ranges::count(range, 3);
assert(ret == 4);
}
}
{
// check that all elements are counted
{
std::array a = {5, 5, 5, 5};
auto ret = std::ranges::count(It(a.data()), Sent(It(a.data() + a.size())), 5);
assert(ret == 4);
}
{
std::array a = {5, 5, 5, 5};
auto range = std::ranges::subrange(It(a.data()), Sent(It(a.data() + a.size())));
auto ret = std::ranges::count(range, 5);
assert(ret == 4);
}
}
}
constexpr bool test() {
test_iterators<int*>();
test_iterators<const int*>();
test_iterators<cpp20_input_iterator<int*>, sentinel_wrapper<cpp20_input_iterator<int*>>>();
test_iterators<bidirectional_iterator<int*>>();
test_iterators<forward_iterator<int*>>();
test_iterators<random_access_iterator<int*>>();
test_iterators<contiguous_iterator<int*>>();
{
// check that projections are used properly and that they are called with the iterator directly
{
int a[] = {1, 2, 3, 4};
auto ret = std::ranges::count(a, a + 4, a + 3, [](int& i) { return &i; });
assert(ret == 1);
}
{
int a[] = {1, 2, 3, 4};
auto ret = std::ranges::count(a, a + 3, [](int& i) { return &i; });
assert(ret == 1);
}
}
{
// check that std::invoke is used
struct S { int i; };
S a[] = { S{1}, S{3}, S{2} };
std::same_as<std::ptrdiff_t> auto ret = std::ranges::count(a, 4, &S::i);
assert(ret == 0);
}
{
// count invocations of the projection
{
int a[] = {1, 2, 3, 4};
int projection_count = 0;
auto ret = std::ranges::count(a, a + 4, 2, [&](int i) { ++projection_count; return i; });
assert(ret == 1);
assert(projection_count == 4);
}
{
int a[] = {1, 2, 3, 4};
int projection_count = 0;
auto ret = std::ranges::count(a, 2, [&](int i) { ++projection_count; return i; });
assert(ret == 1);
assert(projection_count == 4);
}
}
{
// check that an immobile type works
struct NonMovable {
NonMovable(const NonMovable&) = delete;
NonMovable(NonMovable&&) = delete;
constexpr NonMovable(int i_) : i(i_) {}
int i;
bool operator==(const NonMovable&) const = default;
};
{
NonMovable a[] = {9, 8, 4, 3};
auto ret = std::ranges::count(a, a + 4, NonMovable(8));
assert(ret == 1);
}
{
NonMovable a[] = {9, 8, 4, 3};
auto ret = std::ranges::count(a, NonMovable(8));
assert(ret == 1);
}
}
{
// check that difference_type is used
struct DiffTypeIterator {
using difference_type = signed char;
using value_type = int;
int* it = nullptr;
constexpr DiffTypeIterator() = default;
constexpr DiffTypeIterator(int* i) : it(i) {}
constexpr int& operator*() const { return *it; }
constexpr DiffTypeIterator& operator++() { ++it; return *this; }
constexpr void operator++(int) { ++it; }
bool operator==(const DiffTypeIterator&) const = default;
};
{
int a[] = {5, 5, 4, 3, 2, 1};
std::same_as<signed char> decltype(auto) ret =
std::ranges::count(DiffTypeIterator(a), DiffTypeIterator(a + 6), 4);
assert(ret == 1);
}
{
int a[] = {5, 5, 4, 3, 2, 1};
auto range = std::ranges::subrange(DiffTypeIterator(a), DiffTypeIterator(a + 6));
std::same_as<signed char> decltype(auto) ret = std::ranges::count(range, 4);
assert(ret == 1);
}
}
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
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