//===----------------------------------------------------------------------===//
//
// 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
// template<forward_iterator I, sentinel_for<I> S, class Proj = identity,
// indirect_unary_predicate<projected<I, Proj>> Pred>
// constexpr subrange<I> ranges::find_last_if(I first, S last, Pred pred, Proj proj = {});
// template<forward_range R, class Proj = identity,
// indirect_unary_predicate<projected<iterator_t<R>, Proj>> Pred>
// constexpr borrowed_subrange_t<R> ranges::find_last_if(R&& r, Pred pred, Proj proj = {});
#include <algorithm>
#include <array>
#include <cassert>
#include <ranges>
#include "almost_satisfies_types.h"
#include "test_iterators.h"
struct Predicate {
bool operator()(int);
};
template <class It, class Sent = It>
concept HasFindLastIfIt = requires(It it, Sent sent) { std::ranges::find_last_if(it, sent, Predicate{}); };
static_assert(HasFindLastIfIt<int*>);
static_assert(HasFindLastIfIt<forward_iterator<int*>>);
static_assert(!HasFindLastIfIt<cpp20_input_iterator<int*>>);
static_assert(!HasFindLastIfIt<ForwardIteratorNotDerivedFrom>);
static_assert(!HasFindLastIfIt<ForwardIteratorNotIncrementable>);
static_assert(!HasFindLastIfIt<forward_iterator<int*>, SentinelForNotSemiregular>);
static_assert(!HasFindLastIfIt<forward_iterator<int*>, InputRangeNotSentinelEqualityComparableWith>);
static_assert(!HasFindLastIfIt<int*, int>);
static_assert(!HasFindLastIfIt<int, int*>);
template <class Pred>
concept HasFindLastIfPred = requires(int* it, Pred pred) { std::ranges::find_last_if(it, it, pred); };
static_assert(!HasFindLastIfPred<IndirectUnaryPredicateNotCopyConstructible>);
static_assert(!HasFindLastIfPred<IndirectUnaryPredicateNotPredicate>);
template <class R>
concept HasFindLastIfR = requires(R r) { std::ranges::find_last_if(r, Predicate{}); };
static_assert(HasFindLastIfR<std::array<int, 0>>);
static_assert(!HasFindLastIfR<int>);
static_assert(!HasFindLastIfR<ForwardRangeNotDerivedFrom>);
static_assert(!HasFindLastIfR<ForwardRangeNotIncrementable>);
static_assert(!HasFindLastIfR<ForwardRangeNotSentinelSemiregular>);
static_assert(!HasFindLastIfR<ForwardRangeNotSentinelEqualityComparableWith>);
template <class It, class Sent>
constexpr auto make_range(auto& a) {
return std::ranges::subrange(It(std::ranges::begin(a)), Sent(It(std::ranges::end(a))));
}
template <template <class> class IteratorT, template <class> class SentinelT>
constexpr void test_iterator_classes() {
{
using it = IteratorT<int*>;
using sent = SentinelT<it>;
{
int a[] = {1, 2, 3, 4};
std::same_as<std::ranges::subrange<it>> auto ret =
std::ranges::find_last_if(it(a), sent(it(a + 4)), [](int x) { return x == 4; });
assert(base(ret.begin()) == a + 3);
assert(*ret.begin() == 4);
}
{
int a[] = {1, 2, 3, 4};
std::same_as<std::ranges::subrange<it>> auto ret =
std::ranges::find_last_if(make_range<it, sent>(a), [](int x) { return x == 4; });
assert(ret.begin() == it(a + 3));
assert(*ret.begin() == 4);
}
}
{ // check that an empty range works
using it = IteratorT<std::ranges::iterator_t<std::array<int, 0>&>>;
using sent = SentinelT<it>;
{
std::array<int, 0> a = {};
auto ret = std::ranges::find_last_if(it(a.begin()), sent(it(a.end())), [](auto&&) { return true; }).begin();
assert(ret == it(a.end()));
}
{
std::array<int, 0> a = {};
auto ret = std::ranges::find_last_if(make_range<it, sent>(a), [](auto&&) { return true; }).begin();
assert(ret == it(a.end()));
}
}
{ // check that last is returned with no match
using it = IteratorT<int*>;
using sent = SentinelT<it>;
{
int a[] = {1, 1, 1};
auto ret = std::ranges::find_last_if(it(a), sent(it(a + 3)), [](auto&&) { return false; }).begin();
assert(ret == it(a + 3));
}
{
int a[] = {1, 1, 1};
auto ret = std::ranges::find_last_if(make_range<it, sent>(a), [](auto&&) { return false; }).begin();
assert(ret == it(a + 3));
}
}
{ // check that the last element is returned
struct S {
int comp;
int other;
};
using it = IteratorT<S*>;
using sent = SentinelT<it>;
S a[] = {{0, 0}, {0, 2}, {0, 1}};
auto ret = std::ranges::find_last_if(
it(std::begin(a)), sent(it(std::end(a))), [](int c) { return c == 0; }, &S::comp)
.begin();
assert(ret == it(a + 2));
assert((*ret).comp == 0);
assert((*ret).other == 1);
}
{
// count projection and predicate invocation count
{
int a[] = {1, 2, 3, 4};
int predicate_count = 0;
int projection_count = 0;
using it = IteratorT<int*>;
using sent = SentinelT<it>;
auto ret =
std::ranges::find_last_if(
it(a),
sent(it(a + 4)),
[&](int i) {
++predicate_count;
return i == 2;
},
[&](int i) {
++projection_count;
return i;
})
.begin();
assert(ret == it(a + 1));
assert(*ret == 2);
if constexpr (std::bidirectional_iterator<it>) {
assert(predicate_count == 3);
assert(projection_count == 3);
} else {
assert(predicate_count == 4);
assert(projection_count == 4);
}
}
}
}
struct NonConstComparable {
friend constexpr bool operator==(const NonConstComparable&, const NonConstComparable&) { return false; }
friend constexpr bool operator==(NonConstComparable&, NonConstComparable&) { return false; }
friend constexpr bool operator==(const NonConstComparable&, NonConstComparable&) { return false; }
friend constexpr bool operator==(NonConstComparable&, const NonConstComparable&) { return true; }
};
// TODO: this should really use `std::const_iterator`
template <class T>
struct add_const_to_ptr {
using type = T;
};
template <class T>
struct add_const_to_ptr<T*> {
using type = const T*;
};
template <class T>
using add_const_to_ptr_t = typename add_const_to_ptr<T>::type;
constexpr bool test() {
test_iterator_classes<std::type_identity_t, std::type_identity_t>();
test_iterator_classes<add_const_to_ptr_t, std::type_identity_t>();
test_iterator_classes<contiguous_iterator, std::type_identity_t>();
test_iterator_classes<random_access_iterator, std::type_identity_t>();
test_iterator_classes<bidirectional_iterator, std::type_identity_t>();
test_iterator_classes<forward_iterator, std::type_identity_t>();
test_iterator_classes<forward_iterator, sentinel_wrapper>();
{
// 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::find_last_if(a, a + 4, [&](int* i) { return i == a + 3; }, [](int& i) { return &i; }).begin();
assert(ret == a + 3);
}
{
int a[] = {1, 2, 3, 4};
auto ret = std::ranges::find_last_if(a, [&](int* i) { return i == a + 3; }, [](int& i) { return &i; }).begin();
assert(ret == a + 3);
}
}
{
// check that ranges::dangling is returned
[[maybe_unused]] std::same_as<std::ranges::dangling> auto ret =
std::ranges::find_last_if(std::array{1, 2}, [](int) { return false; });
}
{
// check that a subrange 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_if(std::views::all(a), [](int) { return true; });
assert(ret.begin() == a + 3);
assert(*ret.begin() == 4);
}
{
// check that the return type of `iter::operator*` doesn't change
{
NonConstComparable a[] = {NonConstComparable{}};
auto ret = std::ranges::find_last_if(a, a + 1, [](auto&& e) { return e == NonConstComparable{}; }).begin();
assert(ret == a);
}
{
NonConstComparable a[] = {NonConstComparable{}};
auto ret = std::ranges::find_last_if(a, [](auto&& e) { return e == NonConstComparable{}; }).begin();
assert(ret == a);
}
}
return true;
}
int main(int, char**) {
test();
static_assert(test());
return 0;
}
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