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 // UNSUPPORTED: c++03, c++11, c++14, c++17
10
11 // <algorithm>
12
13 // template<input_iterator I, sentinel_for<I> S, class T, output_iterator<const T&> O,
14 // class Proj = identity, indirect_unary_predicate<projected<I, Proj>> Pred>
15 // requires indirectly_copyable<I, O>
16 // constexpr replace_copy_if_result<I, O>
17 // replace_copy_if(I first, S last, O result, Pred pred, const T& new_value,
18 // Proj proj = {}); // Since C++20
19 //
20 // template<input_range R, class T, output_iterator<const T&> O, class Proj = identity,
21 // indirect_unary_predicate<projected<iterator_t<R>, Proj>> Pred>
22 // requires indirectly_copyable<iterator_t<R>, O>
23 // constexpr replace_copy_if_result<borrowed_iterator_t<R>, O>
24 // replace_copy_if(R&& r, O result, Pred pred, const T& new_value,
25 // Proj proj = {}); // Since C++20
26
27 #include <algorithm>
28 #include <array>
29 #include <concepts>
30 #include <functional>
31 #include <ranges>
32 #include <utility>
33
34 #include "almost_satisfies_types.h"
35 #include "counting_predicates.h"
36 #include "counting_projection.h"
37 #include "test_iterators.h"
38
39 struct FalsePredicate {
operator ()FalsePredicate40 constexpr bool operator()(int) { return false; }
41 };
42
43 template <class Iter, class Sent = sentinel_wrapper<Iter>, class OutIter = int*>
44 concept HasReplaceCopyIfIter = requires(Iter&& first, Sent&& last, OutIter&& result) {
45 std::ranges::replace_copy_if(
46 std::forward<Iter>(first), std::forward<Sent>(last), std::forward<OutIter>(result), FalsePredicate{}, 0);
47 };
48
49 static_assert(HasReplaceCopyIfIter<int*>);
50
51 // !input_iterator<I>
52 static_assert(!HasReplaceCopyIfIter<InputIteratorNotDerivedFrom>);
53 static_assert(!HasReplaceCopyIfIter<InputIteratorNotIndirectlyReadable>);
54 static_assert(!HasReplaceCopyIfIter<InputIteratorNotInputOrOutputIterator>);
55
56 // !sentinel_for<S, I>
57 static_assert(!HasReplaceCopyIfIter<int*, SentinelForNotSemiregular>);
58 static_assert(!HasReplaceCopyIfIter<int*, SentinelForNotWeaklyEqualityComparableWith>);
59
60 // !output_iterator<O, const T2&>
61 static_assert(!HasReplaceCopyIfIter<int*, int*, OutputIteratorNotIndirectlyWritable>);
62 static_assert(!HasReplaceCopyIfIter<int*, int*, OutputIteratorNotInputOrOutputIterator>);
63
64 // !indirect_unary_predicate<Pred, projected<I, Proj>> Pred>
65 static_assert(!HasReplaceCopyIfIter<IndirectUnaryPredicateNotCopyConstructible>);
66 static_assert(!HasReplaceCopyIfIter<IndirectUnaryPredicateNotPredicate>);
67
68 // !indirectly_copyable<I, O>
69 static_assert(!HasReplaceCopyIfIter<int*, int*, int**>);
70
71 template <class Range, class OutIter = int*>
72 concept HasReplaceCopyIfRange = requires(Range&& range, OutIter&& result) {
73 std::ranges::replace_copy_if(std::forward<Range>(range), std::forward<OutIter>(result), FalsePredicate{}, 0);
74 };
75
76 template <class T>
77 using R = UncheckedRange<T>;
78
79 static_assert(HasReplaceCopyIfRange<R<int*>>);
80
81 // !input_range<R>
82 static_assert(!HasReplaceCopyIfRange<InputRangeNotDerivedFrom>);
83 static_assert(!HasReplaceCopyIfRange<InputRangeNotIndirectlyReadable>);
84 static_assert(!HasReplaceCopyIfRange<InputRangeNotInputOrOutputIterator>);
85 static_assert(!HasReplaceCopyIfRange<InputRangeNotSentinelSemiregular>);
86 static_assert(!HasReplaceCopyIfRange<InputRangeNotSentinelEqualityComparableWith>);
87
88 // !output_iterator<O, const T2&>
89 static_assert(!HasReplaceCopyIfRange<R<int*>, OutputIteratorNotIndirectlyWritable>);
90 static_assert(!HasReplaceCopyIfRange<R<int*>, OutputIteratorNotInputOrOutputIterator>);
91
92 // !indirect_unary_predicate<Pred, projected<iterator_t<R>, Proj>> Pred>
93 static_assert(!HasReplaceCopyIfRange<R<IndirectUnaryPredicateNotPredicate>>);
94
95 // !indirectly_copyable<iterator_t<R>, O>
96 static_assert(!HasReplaceCopyIfRange<R<int*>, int**>);
97
98 template <int N>
99 struct Data {
100 std::array<int, N> input;
101 int cutoff;
102 int new_value;
103 std::array<int, N> expected;
104 };
105
106 template <class InIter, class Sent, class OutIter, int N>
test(Data<N> d)107 constexpr void test(Data<N> d) {
108 { // iterator overload
109 std::array<int, N> output;
110
111 auto first = InIter(d.input.data());
112 auto last = Sent(InIter(d.input.data() + d.input.size()));
113 auto result = OutIter(output.data());
114
115 auto pred = [&](int i) { return i < d.cutoff; };
116
117 std::same_as<std::ranges::replace_copy_if_result<InIter, OutIter>> decltype(auto) ret =
118 std::ranges::replace_copy_if(std::move(first), std::move(last), std::move(result), pred, d.new_value);
119 assert(base(ret.in) == d.input.data() + d.input.size());
120 assert(base(ret.out) == output.data() + output.size());
121 assert(d.expected == output);
122 }
123
124 { // range overload
125 std::array<int, N> output;
126
127 auto range = std::ranges::subrange(InIter(d.input.data()), Sent(InIter(d.input.data() + d.input.size())));
128 auto result = OutIter(output.data());
129
130 auto pred = [&](int i) { return i < d.cutoff; };
131
132 std::same_as<std::ranges::replace_copy_if_result<InIter, OutIter>> decltype(auto) ret =
133 std::ranges::replace_copy_if(range, result, pred, d.new_value);
134 assert(base(ret.in) == d.input.data() + d.input.size());
135 assert(base(ret.out) == output.data() + output.size());
136 assert(d.expected == output);
137 }
138 }
139
140 template <class InIter, class Sent, class OutIter>
tests()141 constexpr void tests() {
142 // simple test
143 test<InIter, Sent, OutIter, 4>({.input = {1, 2, 3, 4}, .cutoff = 2, .new_value = 5, .expected = {5, 2, 3, 4}});
144 // empty range
145 test<InIter, Sent, OutIter, 0>({.input = {}, .cutoff = 2, .new_value = 5, .expected = {}});
146 // all elements match
147 test<InIter, Sent, OutIter, 4>({.input = {1, 1, 1, 1}, .cutoff = 2, .new_value = 2, .expected = {2, 2, 2, 2}});
148 // no element matches
149 test<InIter, Sent, OutIter, 4>({.input = {1, 1, 1, 1}, .cutoff = 1, .new_value = 3, .expected = {1, 1, 1, 1}});
150 // more elements
151 test<InIter, Sent, OutIter, 7>(
152 {.input = {1, 2, 3, 4, 5, 6, 7}, .cutoff = 3, .new_value = 3, .expected = {3, 3, 3, 4, 5, 6, 7}});
153 // single element - match
154 test<InIter, Sent, OutIter, 1>({.input = {1}, .cutoff = 2, .new_value = 5, .expected = {5}});
155 // single element - no match
156 test<InIter, Sent, OutIter, 1>({.input = {2}, .cutoff = 2, .new_value = 5, .expected = {2}});
157 }
158
159 template <class InIter, class Sent>
test_output_iterators()160 constexpr void test_output_iterators() {
161 tests<InIter, Sent, cpp17_output_iterator<int*>>();
162 tests<InIter, Sent, forward_iterator<int*>>();
163 tests<InIter, Sent, bidirectional_iterator<int*>>();
164 tests<InIter, Sent, random_access_iterator<int*>>();
165 tests<InIter, Sent, contiguous_iterator<int*>>();
166 tests<InIter, Sent, int*>();
167 }
168
169 template <class InIter>
test_sentinels()170 constexpr void test_sentinels() {
171 test_output_iterators<InIter, InIter>();
172 test_output_iterators<InIter, sentinel_wrapper<InIter>>();
173 test_output_iterators<InIter, sized_sentinel<InIter>>();
174 }
175
test()176 constexpr bool test() {
177 test_output_iterators<cpp17_input_iterator<int*>, sentinel_wrapper<cpp17_input_iterator<int*>>>();
178 test_output_iterators<cpp20_input_iterator<int*>, sentinel_wrapper<cpp20_input_iterator<int*>>>();
179 test_sentinels<forward_iterator<int*>>();
180 test_sentinels<bidirectional_iterator<int*>>();
181 test_sentinels<random_access_iterator<int*>>();
182 test_sentinels<contiguous_iterator<int*>>();
183 test_sentinels<int*>();
184 test_sentinels<const int*>();
185
186 { // check that a custom projection works
187 struct S {
188 int i;
189 };
190
191 { // iterator overload
192 S a[] = {{1}, {2}, {3}, {4}};
193 S b[4];
194 auto ret = std::ranges::replace_copy_if(std::begin(a), std::end(a), std::begin(b), FalsePredicate{}, S{2}, &S::i);
195 assert(ret.in == std::end(a));
196 assert(ret.out == std::end(b));
197 assert(std::ranges::equal(a, b, {}, &S::i, &S::i));
198 }
199
200 { // range overload
201 S a[] = {{1}, {2}, {3}, {4}};
202 S b[4];
203 auto ret = std::ranges::replace_copy_if(a, std::begin(b), FalsePredicate{}, S{2}, &S::i);
204 assert(ret.in == std::end(a));
205 assert(ret.out == std::end(b));
206 assert(std::ranges::equal(a, b, {}, &S::i, &S::i));
207 }
208 }
209
210 { // Complexity: exactly `last - first` applications of the corresponding predicate and any projection.
211 { // iterator overload
212 int pred_count = 0;
213 int proj_count = 0;
214 int a[] = {1, 2, 3, 4};
215 int b[4];
216
217 std::ranges::replace_copy_if(
218 std::begin(a), std::end(a), std::begin(b),
219 counting_predicate(FalsePredicate{}, pred_count), 0, counting_projection(proj_count));
220 assert(pred_count == 4);
221 assert(proj_count == 4);
222 }
223
224 { // range overload
225 int pred_count = 0;
226 int proj_count = 0;
227 int a[] = {1, 2, 3, 4};
228 int b[4];
229
230 std::ranges::replace_copy_if(a, std::begin(b),
231 counting_predicate(FalsePredicate{}, pred_count), 0, counting_projection(proj_count));
232 assert(pred_count == 4);
233 assert(proj_count == 4);
234 }
235 }
236
237 { // using different types for the old and new values works
238 struct S {
239 constexpr operator int() const { return 1; }
240 };
241 {
242 int a[] = {0, 0, 2, 3};
243 int b[4];
244 std::ranges::replace_copy_if(std::begin(a), std::end(a), std::begin(b), [](int i) { return i < 2; }, S{});
245 assert(std::ranges::equal(b, std::array{1, 1, 2, 3}));
246 }
247
248 {
249 int a[] = {0, 0, 2, 3};
250 int b[4];
251 std::ranges::replace_copy_if(a, std::begin(b), [](int i) { return i < 2; }, S{});
252 assert(std::ranges::equal(b, std::array{1, 1, 2, 3}));
253 }
254 }
255
256 return true;
257 }
258
main(int,char **)259 int main(int, char**) {
260 test();
261 static_assert(test());
262
263 return 0;
264 }
265