xref: /llvm-project/libcxx/test/std/algorithms/alg.nonmodifying/alg.find/find.pass.cpp (revision f7407411a1dafb9464738d10cc9b64af04a21a8c)
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 // ADDITIONAL_COMPILE_FLAGS(gcc-style-warnings): -Wno-sign-compare
10 // MSVC warning C4389: '==': signed/unsigned mismatch
11 // ADDITIONAL_COMPILE_FLAGS(cl-style-warnings): /wd4389
12 
13 // <algorithm>
14 
15 // template<InputIterator Iter, class T>
16 //   requires HasEqualTo<Iter::value_type, T>
17 //   constexpr Iter   // constexpr after C++17
18 //   find(Iter first, Iter last, const T& value);
19 
20 #include <algorithm>
21 #include <cassert>
22 #include <deque>
23 #include <vector>
24 #include <type_traits>
25 
26 #include "test_macros.h"
27 #include "test_iterators.h"
28 #include "type_algorithms.h"
29 
30 static std::vector<int> comparable_data;
31 
32 template <class ArrayT, class CompareT>
33 struct Test {
34   template <class Iter>
35   TEST_CONSTEXPR_CXX20 void operator()() {
36     ArrayT arr[] = {
37         ArrayT(1), ArrayT(2), ArrayT(3), ArrayT(4), ArrayT(5), ArrayT(6), ArrayT(7), ArrayT(8), ArrayT(9), ArrayT(10)};
38 
39     static_assert(std::is_same<decltype(std::find(Iter(arr), Iter(arr), 0)), Iter>::value, "");
40 
41     { // first element matches
42       Iter iter = std::find(Iter(arr), Iter(arr + 10), CompareT(1));
43       assert(*iter == ArrayT(1));
44       assert(base(iter) == arr);
45     }
46 
47     { // range is empty; return last
48       Iter iter = std::find(Iter(arr), Iter(arr), CompareT(1));
49       assert(base(iter) == arr);
50     }
51 
52     { // if multiple elements match, return the first match
53       ArrayT data[] = {
54           ArrayT(1), ArrayT(2), ArrayT(3), ArrayT(4), ArrayT(5), ArrayT(6), ArrayT(7), ArrayT(5), ArrayT(4)};
55       Iter iter = std::find(Iter(std::begin(data)), Iter(std::end(data)), CompareT(5));
56       assert(*iter == ArrayT(5));
57       assert(base(iter) == data + 4);
58     }
59 
60     { // some element matches
61       Iter iter = std::find(Iter(arr), Iter(arr + 10), CompareT(6));
62       assert(*iter == ArrayT(6));
63       assert(base(iter) == arr + 5);
64     }
65 
66     { // last element matches
67       Iter iter = std::find(Iter(arr), Iter(arr + 10), CompareT(10));
68       assert(*iter == ArrayT(10));
69       assert(base(iter) == arr + 9);
70     }
71 
72     { // if no element matches, last is returned
73       Iter iter = std::find(Iter(arr), Iter(arr + 10), CompareT(20));
74       assert(base(iter) == arr + 10);
75     }
76 
77     if (!TEST_IS_CONSTANT_EVALUATED)
78       comparable_data.clear();
79   }
80 };
81 
82 template <class IndexT>
83 class Comparable {
84   IndexT index_;
85 
86   static IndexT init_index(IndexT i) {
87     IndexT size = static_cast<IndexT>(comparable_data.size());
88     comparable_data.push_back(i);
89     return size;
90   }
91 
92 public:
93   Comparable(IndexT i) : index_(init_index(i)) {}
94 
95   friend bool operator==(const Comparable& lhs, const Comparable& rhs) {
96     return comparable_data[lhs.index_] == comparable_data[rhs.index_];
97   }
98 };
99 
100 #if TEST_STD_VER >= 20
101 template <class ElementT>
102 class TriviallyComparable {
103   ElementT el_;
104 
105 public:
106   explicit constexpr TriviallyComparable(ElementT el) : el_(el) {}
107   bool operator==(const TriviallyComparable&) const = default;
108 };
109 #endif
110 
111 template <class CompareT>
112 struct TestTypes {
113   template <class T>
114   TEST_CONSTEXPR_CXX20 void operator()() {
115     types::for_each(types::cpp17_input_iterator_list<T*>(), Test<T, CompareT>());
116   }
117 };
118 
119 void test_deque() {
120   { // empty deque
121     std::deque<int> data;
122     assert(std::find(data.begin(), data.end(), 4) == data.end());
123   }
124 
125   { // single element - match
126     std::deque<int> data;
127     data.push_back(4);
128     assert(std::find(data.begin(), data.end(), 4) == data.begin());
129   }
130 
131   { // single element - no match
132     std::deque<int> data;
133     data.push_back(3);
134     assert(std::find(data.begin(), data.end(), 4) == data.end());
135   }
136 
137   // many elements
138   int sizes[] = {2, 3, 1023, 1024, 1025, 2047, 2048, 2049};
139   for (auto size : sizes) {
140     { // last element match
141       std::deque<int> data;
142       data.resize(size);
143       std::fill(data.begin(), data.end(), 3);
144       data[size - 1] = 4;
145       assert(std::find(data.begin(), data.end(), 4) == data.end() - 1);
146     }
147 
148     { // second-last element match
149       std::deque<int> data;
150       data.resize(size);
151       std::fill(data.begin(), data.end(), 3);
152       data[size - 2] = 4;
153       assert(std::find(data.begin(), data.end(), 4) == data.end() - 2);
154     }
155 
156     { // no match
157       std::deque<int> data;
158       data.resize(size);
159       std::fill(data.begin(), data.end(), 3);
160       assert(std::find(data.begin(), data.end(), 4) == data.end());
161     }
162   }
163 }
164 
165 TEST_CONSTEXPR_CXX20 bool test() {
166   types::for_each(types::integer_types(), TestTypes<char>());
167   types::for_each(types::integer_types(), TestTypes<int>());
168   types::for_each(types::integer_types(), TestTypes<long long>());
169 #if TEST_STD_VER >= 20
170   Test<TriviallyComparable<char>, TriviallyComparable<char>>().operator()<TriviallyComparable<char>*>();
171   Test<TriviallyComparable<wchar_t>, TriviallyComparable<wchar_t>>().operator()<TriviallyComparable<wchar_t>*>();
172 #endif
173 
174   // TODO: Remove the `_LIBCPP_ENABLE_EXPERIMENTAL` check once we have the FTM guarded or views::join isn't
175   // experimental anymore
176 #if TEST_STD_VER >= 20 && (!defined(_LIBCPP_VERSION) || defined(_LIBCPP_ENABLE_EXPERIMENTAL))
177   {
178     std::vector<std::vector<int>> vec = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
179     auto view                         = vec | std::views::join;
180     assert(std::find(view.begin(), view.end(), 4) == std::next(view.begin(), 3));
181   }
182 #endif
183 
184   return true;
185 }
186 
187 int main(int, char**) {
188   test_deque();
189   test();
190 #if TEST_STD_VER >= 20
191   static_assert(test());
192 #endif
193 
194   Test<Comparable<char>, Comparable<char> >().operator()<Comparable<char>*>();
195   Test<Comparable<wchar_t>, Comparable<wchar_t> >().operator()<Comparable<wchar_t>*>();
196 
197   return 0;
198 }
199