207 lines · cpp
1//===----------------------------------------------------------------------===//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9// <algorithm>10 11// UNSUPPORTED: c++03, c++11, c++14, c++17, c++2012 13// ADDITIONAL_COMPILE_FLAGS(gcc-style-warnings): -Wno-sign-compare14// MSVC warning C4242: 'argument': conversion from 'const _Ty' to 'ElementT', possible loss of data15// MSVC warning C4244: 'argument': conversion from 'const _Ty' to 'ElementT', possible loss of data16// ADDITIONAL_COMPILE_FLAGS(cl-style-warnings): /wd4242 /wd424417 18// template<forward_iterator I, sentinel_for<I> S, class T, class Proj = identity>19// requires indirect_binary_predicate<ranges::equal_to, projected<I, Proj>, const T*>20// constexpr subrange<I> ranges::find_last(I first, S last, const T& value, Proj proj = {});21// template<forward_range R, class T, class Proj = identity>22// requires indirect_binary_predicate<ranges::equal_to, projected<iterator_t<R>, Proj>, const T*>23// constexpr borrowed_subrange_t<R> ranges::find_last(R&& r, const T& value, Proj proj = {});24 25#include <algorithm>26#include <array>27#include <cassert>28#include <memory>29#include <ranges>30#include <vector>31 32#include "almost_satisfies_types.h"33#include "test_iterators.h"34 35struct NotEqualityComparable {};36 37template <class It, class Sent = It>38concept HasFindLastIt = requires(It it, Sent sent) { std::ranges::find_last(it, sent, *it); };39static_assert(HasFindLastIt<int*>);40static_assert(HasFindLastIt<forward_iterator<int*>>);41static_assert(!HasFindLastIt<cpp20_input_iterator<int*>>);42static_assert(!HasFindLastIt<NotEqualityComparable*>);43static_assert(!HasFindLastIt<ForwardIteratorNotDerivedFrom>);44static_assert(!HasFindLastIt<ForwardIteratorNotIncrementable>);45static_assert(!HasFindLastIt<forward_iterator<int*>, SentinelForNotSemiregular>);46static_assert(!HasFindLastIt<forward_iterator<int*>, InputRangeNotSentinelEqualityComparableWith>);47 48static_assert(!HasFindLastIt<int*, int>);49static_assert(!HasFindLastIt<int, int*>);50 51template <class Range, class ValT>52concept HasFindLastR = requires(Range r) { std::ranges::find_last(r, ValT{}); };53static_assert(HasFindLastR<std::array<int, 1>, int>);54static_assert(!HasFindLastR<int, int>);55static_assert(!HasFindLastR<std::array<NotEqualityComparable, 1>, NotEqualityComparable>);56static_assert(!HasFindLastR<ForwardRangeNotDerivedFrom, int>);57static_assert(!HasFindLastR<ForwardRangeNotIncrementable, int>);58static_assert(!HasFindLastR<ForwardRangeNotSentinelSemiregular, int>);59static_assert(!HasFindLastR<ForwardRangeNotSentinelEqualityComparableWith, int>);60 61template <class It, class Sent = It>62constexpr void test_iterators() {63 using ValueT = std::iter_value_t<It>;64 auto make_range = [](auto& a) {65 return std::ranges::subrange(66 It(std::to_address(std::ranges::begin(a))), Sent(It(std::to_address(std::ranges::end(a)))));67 };68 { // simple test69 {70 ValueT a[] = {1, 2, 3, 4};71 72 std::same_as<std::ranges::subrange<It>> auto ret = std::ranges::find_last(It(a), Sent(It(a + 4)), 2);73 assert(base(ret.begin()) == a + 1);74 assert(*ret.begin() == 2);75 }76 {77 ValueT a[] = {1, 2, 3, 4};78 79 std::same_as<std::ranges::subrange<It>> auto ret = std::ranges::find_last(make_range(a), 2);80 assert(base(ret.begin()) == a + 1);81 assert(*ret.begin() == 2);82 }83 }84 85 { // check that an empty range works86 {87 std::array<ValueT, 0> a = {};88 89 auto ret = std::ranges::find_last(It(a.data()), Sent(It(a.data())), 1).begin();90 assert(ret == It(a.data()));91 }92 {93 std::array<ValueT, 0> a = {};94 95 auto ret = std::ranges::find_last(make_range(a), 1).begin();96 assert(ret == It(a.data()));97 }98 }99 100 { // check that last is returned with no match101 {102 ValueT a[] = {1, 1, 1};103 104 auto ret = std::ranges::find_last(It(a), Sent(It(a + 3)), 0).begin();105 assert(ret == It(a + 3));106 }107 {108 ValueT a[] = {1, 1, 1};109 110 auto ret = std::ranges::find_last(make_range(a), 0).begin();111 assert(ret == It(a + 3));112 }113 }114}115 116template <template <class> class IteratorT>117constexpr void test_iterator_classes() {118 { // check that the last element is returned119 struct S {120 int comp;121 int other;122 };123 using it = IteratorT<S*>;124 S a[] = {{0, 0}, {0, 2}, {0, 1}};125 126 auto ret = std::ranges::find_last(it(std::begin(a)), it(std::end(a)), 0, &S::comp).begin();127 assert(ret == it(a + 2));128 assert((*ret).comp == 0);129 assert((*ret).other == 1);130 }131 132 {133 // count invocations of the projection134 using it = IteratorT<int*>;135 136 int a[] = {1, 2, 3, 4};137 int projection_count = 0;138 139 auto ret = std::ranges::find_last(it(std::begin(a)), it(std::end(a)), 2, [&](int i) {140 ++projection_count;141 return i;142 }).begin();143 assert(ret == it(a + 1));144 assert(*ret == 2);145 if (std::bidirectional_iterator<it>) {146 assert(projection_count == 3);147 } else {148 assert(projection_count == 4); // must go through entire list149 }150 }151}152 153template <class ElementT>154class TriviallyComparable {155 ElementT el_;156 157public:158 constexpr TriviallyComparable(ElementT el) : el_(el) {}159 bool operator==(const TriviallyComparable&) const = default;160};161 162constexpr bool test() {163 types::for_each(types::type_list<char, int, TriviallyComparable<char>>{}, []<class T> {164 types::for_each(types::forward_iterator_list<T*>{}, []<class Iter> {165 test_iterators<Iter>();166 test_iterators<Iter, sentinel_wrapper<Iter>>();167 test_iterators<Iter, sized_sentinel<Iter>>();168 });169 });170 171 test_iterator_classes<forward_iterator>();172 test_iterator_classes<bidirectional_iterator>();173 test_iterator_classes<random_access_iterator>();174 test_iterator_classes<std::type_identity_t>();175 176 {177 std::vector<std::vector<int>> vec = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};178 179 auto view = vec | std::views::join;180 assert(std::ranges::find_last(view.begin(), view.end(), 4).begin() == std::next(view.begin(), 3));181 assert(std::ranges::find_last(view, 4).begin() == std::next(view.begin(), 3));182 }183 184 {185 // check that an iterator is returned with a borrowing range186 int a[] = {1, 2, 3, 4};187 188 std::same_as<std::ranges::subrange<int*>> auto ret = std::ranges::find_last(std::views::all(a), 1);189 assert(ret.begin() == a);190 assert(*ret.begin() == 1);191 }192 193 {194 // check that dangling ranges are dangling195 std::same_as<std::ranges::dangling> auto ret = std::ranges::find_last(std::vector<int>(), 0);196 (void)ret;197 }198 199 return true;200}201 202int main(int, char**) {203 test();204 static_assert(test());205 return 0;206}207