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 
13 // template<input_iterator I, sentinel_for<I> S, class T, class Proj = identity,
14 //          indirect_unary_predicate<projected<I, Proj>> Pred>
15 //   requires indirectly_writable<I, const T&>
16 //   constexpr I ranges::replace_if(I first, S last, Pred pred, const T& new_value, Proj proj = {});
17 // template<input_range R, class T, class Proj = identity,
18 //          indirect_unary_predicate<projected<iterator_t<R>, Proj>> Pred>
19 //   requires indirectly_writable<iterator_t<R>, const T&>
20 //   constexpr borrowed_iterator_t<R>
21 //     ranges::replace_if(R&& r, Pred pred, const T& new_value, 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 {
33   bool operator()(auto&&) { return false; }
34 };
35 
36 template <class Iter, class Sent = sentinel_wrapper<Iter>>
37 concept HasReplaceIt = requires(Iter iter, Sent sent) { std::ranges::replace_if(iter, sent, FalsePredicate{}, 0); };
38 
39 static_assert(HasReplaceIt<int*>);
40 static_assert(!HasReplaceIt<InputIteratorNotDerivedFrom>);
41 static_assert(!HasReplaceIt<InputIteratorNotIndirectlyReadable>);
42 static_assert(!HasReplaceIt<InputIteratorNotInputOrOutputIterator>);
43 static_assert(!HasReplaceIt<int*, SentinelForNotSemiregular>);
44 static_assert(!HasReplaceIt<int*, SentinelForNotWeaklyEqualityComparableWith>);
45 static_assert(!HasReplaceIt<int**>); // not indirectly_writable
46 static_assert(!HasReplaceIt<IndirectBinaryPredicateNotIndirectlyReadable>);
47 
48 template <class Range>
49 concept HasReplaceR = requires(Range range) { std::ranges::replace_if(range, FalsePredicate{}, 0); };
50 
51 static_assert(HasReplaceR<UncheckedRange<int*>>);
52 static_assert(!HasReplaceR<InputRangeNotDerivedFrom>);
53 static_assert(!HasReplaceR<InputRangeNotIndirectlyReadable>);
54 static_assert(!HasReplaceR<InputRangeNotInputOrOutputIterator>);
55 static_assert(!HasReplaceR<InputRangeNotSentinelSemiregular>);
56 static_assert(!HasReplaceR<InputRangeNotSentinelEqualityComparableWith>);
57 static_assert(!HasReplaceR<UncheckedRange<int**>>); // not indirectly_writable
58 static_assert(!HasReplaceR<InputRangeIndirectBinaryPredicateNotIndirectlyReadable>);
59 
60 template <class Iter, class Sent, int N, class Pred>
61 constexpr void test(std::array<int, N> a_, Pred pred, int val, std::array<int, N> expected) {
62   {
63     auto a = a_;
64     std::same_as<Iter> auto ret = std::ranges::replace_if(Iter(a.data()), Sent(Iter(a.data() + N)),
65                                                           pred,
66                                                           val);
67     assert(base(ret) == a.data() + N);
68     assert(a == expected);
69   }
70   {
71     auto a = a_;
72     auto range = std::ranges::subrange(Iter(a.data()), Sent(Iter(a.data() + N)));
73     std::same_as<Iter> auto ret = std::ranges::replace_if(range, pred, val);
74     assert(base(ret) == a.data() + N);
75     assert(a == expected);
76   }
77 }
78 
79 template <class Iter, class Sent = Iter>
80 constexpr void test_iterators() {
81   // simple test
82   test<Iter, Sent, 4>({1, 2, 3, 4}, [](int i) { return i < 3; }, 23, {23, 23, 3, 4});
83   // no match
84   test<Iter, Sent, 4>({1, 2, 3, 4}, [](int i) { return i < 0; }, 23, {1, 2, 3, 4});
85   // all match
86   test<Iter, Sent, 4>({1, 2, 3, 4}, [](int i) { return i > 0; }, 23, {23, 23, 23, 23});
87   // empty range
88   test<Iter, Sent, 0>({}, [](int i) { return i > 0; }, 23, {});
89   // single element range
90   test<Iter, Sent, 1>({1}, [](int i) { return i > 0; }, 2, {2});
91 }
92 
93 constexpr bool test() {
94   test_iterators<cpp17_input_iterator<int*>, sentinel_wrapper<cpp17_input_iterator<int*>>>();
95   test_iterators<cpp20_input_iterator<int*>, sentinel_wrapper<cpp20_input_iterator<int*>>>();
96   test_iterators<forward_iterator<int*>>();
97   test_iterators<bidirectional_iterator<int*>>();
98   test_iterators<random_access_iterator<int*>>();
99   test_iterators<contiguous_iterator<int*>>();
100   test_iterators<int*>();
101 
102   { // check that the projection is used
103     struct S {
104       constexpr S(int i_) : i(i_) {}
105       int i;
106     };
107     {
108       S a[] = {1, 2, 3, 4};
109       std::ranges::replace_if(a, a + 4, [](int i) { return i == 3; }, S{0}, &S::i);
110     }
111     {
112       S a[] = {1, 2, 3, 4};
113       std::ranges::replace_if(a, [](int i) { return i == 3; }, S{0}, &S::i);
114     }
115   }
116 
117   { // check that std::invoke is used
118     struct S {
119       constexpr S(int i_) : i(i_) {}
120       constexpr bool check() const { return false; }
121       constexpr const S& identity() const { return *this; }
122       int i;
123     };
124     {
125       S a[] = {1, 2, 3, 4};
126       auto ret = std::ranges::replace_if(std::begin(a), std::end(a), &S::check, S{2}, &S::identity);
127       assert(ret == std::end(a));
128     }
129     {
130       S a[] = {1, 2, 3, 4};
131       auto ret = std::ranges::replace_if(a, &S::check, S{2}, &S::identity);
132       assert(ret == std::end(a));
133     }
134   }
135 
136   { // check that the implicit conversion to bool works
137     {
138       int a[] = {1, 2, 2, 4};
139       auto ret = std::ranges::replace_if(std::begin(a), std::end(a), [](int) { return BooleanTestable{false}; }, 2);
140       assert(ret == std::end(a));
141     }
142     {
143       int a[] = {1, 2, 2, 4};
144       auto ret = std::ranges::replace_if(a, [](int) { return BooleanTestable{false}; }, 2);
145       assert(ret == std::end(a));
146     }
147   }
148 
149   { // check that std::ranges::dangling is returned
150     [[maybe_unused]] std::same_as<std::ranges::dangling> decltype(auto) ret =
151         std::ranges::replace_if(std::array {1, 2, 3, 4}, [](int) { return false; }, 1);
152   }
153 
154   { // check that the complexity requirements are met
155     {
156       int predicateCount = 0;
157       auto pred = [&](int) { ++predicateCount; return false; };
158       auto projectionCount = 0;
159       auto proj = [&](int i) { ++projectionCount; return i; };
160       int a[] = {1, 2, 3, 4, 5};
161       auto ret = std::ranges::replace_if(a, a + 5, pred, 1, proj);
162       assert(ret == a + 5);
163       assert(predicateCount == 5);
164       assert(projectionCount == 5);
165     }
166     {
167       int predicateCount = 0;
168       auto pred = [&](int) { ++predicateCount; return false; };
169       auto projectionCount = 0;
170       auto proj = [&](int i) { ++projectionCount; return i; };
171       int a[] = {1, 2, 3, 4, 5};
172       auto ret = std::ranges::replace_if(a, pred, 1, proj);
173       assert(ret == a + 5);
174       assert(predicateCount == 5);
175       assert(projectionCount == 5);
176     }
177   }
178 
179   return true;
180 }
181 
182 int main(int, char**) {
183   test();
184   static_assert(test());
185 
186   return 0;
187 }
188