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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, c++20
// ADDITIONAL_COMPILE_FLAGS(gcc-style-warnings): -Wno-sign-compare
// MSVC warning C4242: 'argument': conversion from 'const _Ty' to 'ElementT', possible loss of data
// MSVC warning C4244: 'argument': conversion from 'const _Ty' to 'ElementT', possible loss of data
// ADDITIONAL_COMPILE_FLAGS(cl-style-warnings): /wd4242 /wd4244
// template<forward_iterator I, sentinel_for<I> S, class T, class Proj = identity>
// requires indirect_binary_predicate<ranges::equal_to, projected<I, Proj>, const T*>
// constexpr subrange<I> ranges::find_last(I first, S last, const T& value, Proj proj = {});
// template<forward_range R, class T, class Proj = identity>
// requires indirect_binary_predicate<ranges::equal_to, projected<iterator_t<R>, Proj>, const T*>
// constexpr borrowed_subrange_t<R> ranges::find_last(R&& r, const T& value, Proj proj = {});
#include <algorithm>
#include <array>
#include <cassert>
#include <ranges>
#include <vector>
#include "almost_satisfies_types.h"
#include "test_iterators.h"
struct NotEqualityComparable {};
template <class It, class Sent = It>
concept HasFindLastIt = requires(It it, Sent sent) { std::ranges::find_last(it, sent, *it); };
static_assert(HasFindLastIt<int*>);
static_assert(HasFindLastIt<forward_iterator<int*>>);
static_assert(!HasFindLastIt<cpp20_input_iterator<int*>>);
static_assert(!HasFindLastIt<NotEqualityComparable*>);
static_assert(!HasFindLastIt<ForwardIteratorNotDerivedFrom>);
static_assert(!HasFindLastIt<ForwardIteratorNotIncrementable>);
static_assert(!HasFindLastIt<forward_iterator<int*>, SentinelForNotSemiregular>);
static_assert(!HasFindLastIt<forward_iterator<int*>, InputRangeNotSentinelEqualityComparableWith>);
static_assert(!HasFindLastIt<int*, int>);
static_assert(!HasFindLastIt<int, int*>);
template <class Range, class ValT>
concept HasFindLastR = requires(Range r) { std::ranges::find_last(r, ValT{}); };
static_assert(HasFindLastR<std::array<int, 1>, int>);
static_assert(!HasFindLastR<int, int>);
static_assert(!HasFindLastR<std::array<NotEqualityComparable, 1>, NotEqualityComparable>);
static_assert(!HasFindLastR<ForwardRangeNotDerivedFrom, int>);
static_assert(!HasFindLastR<ForwardRangeNotIncrementable, int>);
static_assert(!HasFindLastR<ForwardRangeNotSentinelSemiregular, int>);
static_assert(!HasFindLastR<ForwardRangeNotSentinelEqualityComparableWith, int>);
template <class It, class Sent = It>
constexpr void test_iterators() {
using ValueT = std::iter_value_t<It>;
auto make_range = [](auto& a) {
return std::ranges::subrange(It(std::ranges::begin(a)), Sent(It(std::ranges::end(a))));
};
{ // simple test
{
ValueT a[] = {1, 2, 3, 4};
std::same_as<std::ranges::subrange<It>> auto ret = std::ranges::find_last(It(a), Sent(It(a + 4)), 2);
assert(base(ret.begin()) == a + 1);
assert(*ret.begin() == 2);
}
{
ValueT a[] = {1, 2, 3, 4};
std::same_as<std::ranges::subrange<It>> auto ret = std::ranges::find_last(make_range(a), 2);
assert(base(ret.begin()) == a + 1);
assert(*ret.begin() == 2);
}
}
{ // check that an empty range works
{
std::array<ValueT, 0> a = {};
auto ret = std::ranges::find_last(It(a.data()), Sent(It(a.data())), 1).begin();
assert(ret == It(a.data()));
}
{
std::array<ValueT, 0> a = {};
auto ret = std::ranges::find_last(make_range(a), 1).begin();
assert(ret == It(a.begin()));
}
}
{ // check that last is returned with no match
{
ValueT a[] = {1, 1, 1};
auto ret = std::ranges::find_last(It(a), Sent(It(a + 3)), 0).begin();
assert(ret == It(a + 3));
}
{
ValueT a[] = {1, 1, 1};
auto ret = std::ranges::find_last(make_range(a), 0).begin();
assert(ret == It(a + 3));
}
}
}
template <template <class> class IteratorT>
constexpr void test_iterator_classes() {
{ // check that the last element is returned
struct S {
int comp;
int other;
};
using it = IteratorT<S*>;
S a[] = {{0, 0}, {0, 2}, {0, 1}};
auto ret = std::ranges::find_last(it(std::begin(a)), it(std::end(a)), 0, &S::comp).begin();
assert(ret == it(a + 2));
assert((*ret).comp == 0);
assert((*ret).other == 1);
}
{
// count invocations of the projection
using it = IteratorT<int*>;
int a[] = {1, 2, 3, 4};
int projection_count = 0;
auto ret = std::ranges::find_last(it(std::begin(a)), it(std::end(a)), 2, [&](int i) {
++projection_count;
return i;
}).begin();
assert(ret == it(a + 1));
assert(*ret == 2);
if (std::bidirectional_iterator<it>) {
assert(projection_count == 3);
} else {
assert(projection_count == 4); // must go through entire list
}
}
}
template <class ElementT>
class TriviallyComparable {
ElementT el_;
public:
constexpr TriviallyComparable(ElementT el) : el_(el) {}
bool operator==(const TriviallyComparable&) const = default;
};
constexpr bool test() {
types::for_each(types::type_list<char, int, TriviallyComparable<char>>{}, []<class T> {
types::for_each(types::forward_iterator_list<T*>{}, []<class Iter> {
test_iterators<Iter>();
test_iterators<Iter, sentinel_wrapper<Iter>>();
test_iterators<Iter, sized_sentinel<Iter>>();
});
});
test_iterator_classes<forward_iterator>();
test_iterator_classes<bidirectional_iterator>();
test_iterator_classes<random_access_iterator>();
test_iterator_classes<std::type_identity_t>();
{
std::vector<std::vector<int>> vec = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
auto view = vec | std::views::join;
assert(std::ranges::find_last(view.begin(), view.end(), 4).begin() == std::next(view.begin(), 3));
assert(std::ranges::find_last(view, 4).begin() == std::next(view.begin(), 3));
}
{
// check that an iterator is returned with a borrowing range
int a[] = {1, 2, 3, 4};
std::same_as<std::ranges::subrange<int*>> auto ret = std::ranges::find_last(std::views::all(a), 1);
assert(ret.begin() == a);
assert(*ret.begin() == 1);
}
{
// check that dangling ranges are dangling
std::same_as<std::ranges::dangling> auto ret = std::ranges::find_last(std::vector<int>(), 0);
(void)ret;
}
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
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