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-exception
6 //
7 //===----------------------------------------------------------------------===//
8
9 // <algorithm>
10
11 // UNSUPPORTED: c++03, c++11, c++14, c++17
12 // UNSUPPORTED: libcpp-has-no-incomplete-ranges
13
14 // template<permutable I, sentinel_for<I> S, class Proj = identity,
15 // indirect_unary_predicate<projected<I, Proj>> Pred>
16 // constexpr subrange<I> ranges::remove_if(I first, S last, Pred pred, Proj proj = {});
17 // template<forward_range R, class Proj = identity,
18 // indirect_unary_predicate<projected<iterator_t<R>, Proj>> Pred>
19 // requires permutable<iterator_t<R>>
20 // constexpr borrowed_subrange_t<R>
21 // ranges::remove_if(R&& r, Pred pred, Proj proj = {});
22
23 #include <algorithm>
24 #include <array>
25 #include <cassert>
26 #include <ranges>
27
28 #include "almost_satisfies_types.h"
29 #include "boolean_testable.h"
30 #include "test_iterators.h"
31
32 struct FalsePredicate {
operator ()FalsePredicate33 bool operator()(int) { return false; }
34 };
35
36 template <class Iter, class Sent = sentinel_wrapper<Iter>>
37 concept HasRemoveIfIt = requires(Iter first, Sent last) { std::ranges::remove_if(first, last, FalsePredicate{}); };
38
39 static_assert(HasRemoveIfIt<int*>);
40 static_assert(!HasRemoveIfIt<PermutableNotForwardIterator>);
41 static_assert(!HasRemoveIfIt<PermutableNotSwappable>);
42 static_assert(!HasRemoveIfIt<int*, SentinelForNotSemiregular>);
43 static_assert(!HasRemoveIfIt<int*, SentinelForNotWeaklyEqualityComparableWith>);
44 static_assert(!HasRemoveIfIt<int**>); // not indirect_unary_predicate
45
46 template <class Range>
47 concept HasRemoveIfR = requires(Range range) { std::ranges::remove_if(range, FalsePredicate{}); };
48
49 static_assert(HasRemoveIfR<UncheckedRange<int*>>);
50 static_assert(!HasRemoveIfR<PermutableRangeNotForwardIterator>);
51 static_assert(!HasRemoveIfR<PermutableRangeNotSwappable>);
52 static_assert(!HasRemoveIfR<SentinelForNotSemiregular>);
53 static_assert(!HasRemoveIfR<SentinelForNotWeaklyEqualityComparableWith>);
54 static_assert(!HasRemoveIfR<UncheckedRange<int**>>); // not indirect_unary_predicate
55
56 template <int N, int M>
57 struct Data {
58 std::array<int, N> input;
59 std::array<int, M> expected;
60 int cutoff;
61 };
62
63 template <class Iter, class Sent, int N, int M>
test(Data<N,M> d)64 constexpr void test(Data<N, M> d) {
65 { // iterator overload
66 auto input = d.input;
67
68 auto first = Iter(input.data());
69 auto last = Sent(Iter(input.data() + input.size()));
70
71 std::same_as<std::ranges::subrange<Iter>> decltype(auto) ret =
72 std::ranges::remove_if(std::move(first), std::move(last), [&](int i) { return i < d.cutoff; });
73
74 assert(base(ret.begin()) == input.data() + M);
75 assert(base(ret.end()) == input.data() + N);
76 assert(std::ranges::equal(input.data(), base(ret.begin()), d.expected.begin(), d.expected.end()));
77 }
78
79 { // range overload
80 auto input = d.input;
81 auto range = std::ranges::subrange(Iter(input.data()), Sent(Iter(input.data() + input.size())));
82
83 std::same_as<std::ranges::subrange<Iter>> decltype(auto) ret = std::ranges::remove_if(range, [&](int i) {
84 return i < d.cutoff;
85 });
86
87 assert(base(ret.begin()) == input.data() + M);
88 assert(base(ret.end()) == input.data() + N);
89 assert(std::ranges::equal(base(input.begin()), base(ret.begin()), d.expected.begin(), d.expected.end()));
90 }
91 }
92
93 template <class Iter, class Sent>
tests()94 constexpr void tests() {
95 // simple test
96 test<Iter, Sent, 6, 2>({.input = {1, 2, 3, 4, 5, 6}, .expected = {5, 6}, .cutoff = 5});
97 // empty range
98 test<Iter, Sent, 0, 0>({});
99 // single element range - no match
100 test<Iter, Sent, 1, 1>({.input = {1}, .expected = {1}, .cutoff = 1});
101 // single element range - match
102 test<Iter, Sent, 1, 0>({.input = {1}, .expected = {}, .cutoff = 2});
103 // two element range
104 test<Iter, Sent, 2, 1>({.input = {1, 2}, .expected = {2}, .cutoff = 2});
105 // all elements match
106 test<Iter, Sent, 5, 0>({.input = {1, 1, 1, 1, 1}, .expected = {}, .cutoff = 2});
107 // no elements match
108 test<Iter, Sent, 5, 5>({.input = {1, 1, 1, 1, 1}, .expected = {1, 1, 1, 1, 1}, .cutoff = 0});
109 // the relative order of elements isn't changed
110 test<Iter, Sent, 8, 7>({.input = {1, 2, 3, 2, 3, 4, 2, 5}, .expected = {2, 3, 2, 3, 4, 2, 5}, .cutoff = 2});
111 // multiple matches in a row
112 test<Iter, Sent, 5, 3>({.input = {1, 2, 2, 2, 1}, .expected = {2, 2, 2}, .cutoff = 2});
113 // only the last element matches
114 test<Iter, Sent, 3, 2>({.input = {2, 2, 1}, .expected = {2, 2}, .cutoff = 2});
115 // only the last element doesn't match
116 test<Iter, Sent, 3, 1>({.input = {1, 1, 2}, .expected = {2}, .cutoff = 2});
117 }
118
119 template <class Iter>
test_sentinels()120 constexpr void test_sentinels() {
121 tests<Iter, Iter>();
122 tests<Iter, sentinel_wrapper<Iter>>();
123 tests<Iter, sized_sentinel<Iter>>();
124 }
125
test_iterators()126 constexpr void test_iterators() {
127 test_sentinels<forward_iterator<int*>>();
128 test_sentinels<bidirectional_iterator<int*>>();
129 test_sentinels<random_access_iterator<int*>>();
130 test_sentinels<contiguous_iterator<int*>>();
131 test_sentinels<int*>();
132 }
133
test()134 constexpr bool test() {
135 test_iterators();
136
137 { // check that ranges::dangling is returned
138 [[maybe_unused]] std::same_as<std::ranges::dangling> decltype(auto) ret =
139 std::ranges::remove_if(std::array{1, 2, 3, 4}, [](int i) { return i < 0; });
140 }
141
142 {// check complexity requirements
143
144 // This is https://llvm.org/PR56382 - clang-format behaves weird if function-local structs are used
145 // clang-format off
146 {
147 int comp_count = 0;
148 auto comp = [&](int i) {
149 ++comp_count;
150 return i == 0;
151 };
152 int proj_count = 0;
153 auto proj = [&](int i) {
154 ++proj_count;
155 return i;
156 };
157 int a[] = {1, 2, 3, 4};
158 auto ret = std::ranges::remove_if(std::begin(a), std::end(a), comp, proj);
159 assert(ret.begin() == std::end(a) && ret.end() == std::end(a));
160 assert(comp_count == 4);
161 assert(proj_count == 4);
162 }
163 {
164 int comp_count = 0;
165 auto comp = [&](int i) {
166 ++comp_count;
167 return i == 0;
168 };
169 int proj_count = 0;
170 auto proj = [&](int i) {
171 ++proj_count;
172 return i;
173 };
174 int a[] = {1, 2, 3, 4};
175 auto ret = std::ranges::remove_if(a, comp, proj);
176 assert(ret.begin() == std::end(a) && ret.end() == std::end(a));
177 assert(comp_count == 4);
178 assert(proj_count == 4);
179 }
180 }
181
182 { // check that std::invoke is used
183 struct S {
184 constexpr S& identity() { return *this; }
185 constexpr bool predicate() const { return true; }
186 };
187 {
188 S a[4] = {};
189 auto ret = std::ranges::remove_if(std::begin(a), std::end(a), &S::predicate, &S::identity);
190 assert(ret.begin() == std::begin(a));
191 assert(ret.end() == std::end(a));
192 }
193 {
194 S a[4] = {};
195 auto ret = std::ranges::remove_if(a, &S::predicate, &S::identity);
196 assert(ret.begin() == std::begin(a));
197 assert(ret.end() == std::end(a));
198 }
199 }
200
201 {
202 // check that the implicit conversion to bool works
203 {
204 int a[] = {1, 2, 3, 4};
205 auto ret = std::ranges::remove_if(a, a + 4, [](const int& i) { return BooleanTestable{i == 3}; });
206 assert(ret.begin() == a + 3);
207 }
208 {
209 int a[] = {1, 2, 3, 4};
210 auto ret = std::ranges::remove_if(a, [](const int& b) { return BooleanTestable{b == 3}; });
211 assert(ret.begin() == a + 3);
212 }
213 }
214
215 return true;
216 }
217 // clang-format on
218
main(int,char **)219 int main(int, char**) {
220 test();
221 static_assert(test());
222
223 return 0;
224 }
225