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 // <numeric>
10 // UNSUPPORTED: clang-8
11 // UNSUPPORTED: gcc-9
12 
13 // Became constexpr in C++20
14 // template <InputIterator InIter,
15 //           OutputIterator<auto, const InIter::value_type&> OutIter,
16 //           Callable<auto, const InIter::value_type&, const InIter::value_type&> BinaryOperation>
17 //   requires Constructible<InIter::value_type, InIter::reference>
18 //         && OutputIterator<OutIter, BinaryOperation::result_type>
19 //         && MoveAssignable<InIter::value_type>
20 //         && CopyConstructible<BinaryOperation>
21 //   OutIter
22 //   adjacent_difference(InIter first, InIter last, OutIter result, BinaryOperation binary_op);
23 
24 #include <numeric>
25 #include <functional>
26 #include <string>
27 #include <cassert>
28 
29 #include "test_macros.h"
30 #include "test_iterators.h"
31 
32 #if TEST_STD_VER > 17
33 struct rvalue_subtractable
34 {
35     bool correctOperatorUsed = false;
36 
37     // make sure the predicate is passed an rvalue and an lvalue (so check that the first argument was moved)
38     constexpr rvalue_subtractable operator()(rvalue_subtractable const&, rvalue_subtractable&& r) {
39         r.correctOperatorUsed = true;
40         return std::move(r);
41     }
42 };
43 
44 constexpr rvalue_subtractable operator-(rvalue_subtractable const&, rvalue_subtractable& rhs)
45 {
46     rhs.correctOperatorUsed = false;
47     return rhs;
48 }
49 
50 constexpr rvalue_subtractable operator-(rvalue_subtractable const&, rvalue_subtractable&& rhs)
51 {
52     rhs.correctOperatorUsed = true;
53     return std::move(rhs);
54 }
55 
56 constexpr void
57 test_use_move()
58 {
59     const std::size_t size = 100;
60     rvalue_subtractable arr[size];
61     rvalue_subtractable res1[size];
62     rvalue_subtractable res2[size];
63     std::adjacent_difference(arr, arr + size, res1);
64     std::adjacent_difference(arr, arr + size, res2, /*predicate=*/rvalue_subtractable());
65     // start at 1 because the first element is not moved
66     for (unsigned i = 1; i < size; ++i) assert(res1[i].correctOperatorUsed);
67     for (unsigned i = 1; i < size; ++i) assert(res2[i].correctOperatorUsed);
68 }
69 #endif // TEST_STD_VER > 17
70 
71 // C++20 can use string in constexpr evaluation, but both libc++ and MSVC
72 // don't have the support yet. In these cases omit the constexpr test.
73 // FIXME Remove constexpr string workaround introduced in D90569
74 #if TEST_STD_VER > 17 && \
75 	(!defined(__cpp_lib_constexpr_string) || __cpp_lib_constexpr_string < 201907L)
76 void
77 #else
78 TEST_CONSTEXPR_CXX20 void
79 #endif
80 test_string()
81 {
82     std::string sa[] = {"a", "b", "c"};
83     std::string sr[] = {"a", "ba", "cb"};
84     std::string output[3];
85     std::adjacent_difference(sa, sa + 3, output, std::plus<std::string>());
86     for (unsigned i = 0; i < 3; ++i) assert(output[i] == sr[i]);
87 }
88 
89 template <class InIter, class OutIter>
90 TEST_CONSTEXPR_CXX20 void
91 test()
92 {
93     int ia[] = {15, 10, 6, 3, 1};
94     int ir[] = {15, 25, 16, 9, 4};
95     const unsigned s = sizeof(ia) / sizeof(ia[0]);
96     int ib[s] = {0};
97     OutIter r = std::adjacent_difference(InIter(ia), InIter(ia+s), OutIter(ib),
98                                          std::plus<int>());
99     assert(base(r) == ib + s);
100     for (unsigned i = 0; i < s; ++i)
101         assert(ib[i] == ir[i]);
102 }
103 
104 #if TEST_STD_VER >= 11
105 
106 class Y;
107 
108 class X
109 {
110     int i_;
111 
112     TEST_CONSTEXPR_CXX20 X& operator=(const X&);
113 public:
114     TEST_CONSTEXPR_CXX20 explicit X(int i) : i_(i) {}
115     TEST_CONSTEXPR_CXX20 X(const X& x) : i_(x.i_) {}
116     TEST_CONSTEXPR_CXX20 X& operator=(X&& x)
117     {
118         i_ = x.i_;
119         x.i_ = -1;
120         return *this;
121     }
122 
123     TEST_CONSTEXPR_CXX20 friend X operator-(const X& x, const X& y) {return X(x.i_ - y.i_);}
124 
125     friend class Y;
126 };
127 
128 class Y
129 {
130     int i_;
131 
132     TEST_CONSTEXPR_CXX20 Y& operator=(const Y&);
133 public:
134     TEST_CONSTEXPR_CXX20 explicit Y(int i) : i_(i) {}
135     TEST_CONSTEXPR_CXX20 Y(const Y& y) : i_(y.i_) {}
136     TEST_CONSTEXPR_CXX20 void operator=(const X& x) {i_ = x.i_;}
137 };
138 
139 #endif
140 
141 
142 TEST_CONSTEXPR_CXX20 bool
143 test()
144 {
145     test<cpp17_input_iterator<const int*>, output_iterator<int*> >();
146     test<cpp17_input_iterator<const int*>, forward_iterator<int*> >();
147     test<cpp17_input_iterator<const int*>, bidirectional_iterator<int*> >();
148     test<cpp17_input_iterator<const int*>, random_access_iterator<int*> >();
149     test<cpp17_input_iterator<const int*>, int*>();
150 
151     test<forward_iterator<const int*>, output_iterator<int*> >();
152     test<forward_iterator<const int*>, forward_iterator<int*> >();
153     test<forward_iterator<const int*>, bidirectional_iterator<int*> >();
154     test<forward_iterator<const int*>, random_access_iterator<int*> >();
155     test<forward_iterator<const int*>, int*>();
156 
157     test<bidirectional_iterator<const int*>, output_iterator<int*> >();
158     test<bidirectional_iterator<const int*>, forward_iterator<int*> >();
159     test<bidirectional_iterator<const int*>, bidirectional_iterator<int*> >();
160     test<bidirectional_iterator<const int*>, random_access_iterator<int*> >();
161     test<bidirectional_iterator<const int*>, int*>();
162 
163     test<random_access_iterator<const int*>, output_iterator<int*> >();
164     test<random_access_iterator<const int*>, forward_iterator<int*> >();
165     test<random_access_iterator<const int*>, bidirectional_iterator<int*> >();
166     test<random_access_iterator<const int*>, random_access_iterator<int*> >();
167     test<random_access_iterator<const int*>, int*>();
168 
169     test<const int*, output_iterator<int*> >();
170     test<const int*, forward_iterator<int*> >();
171     test<const int*, bidirectional_iterator<int*> >();
172     test<const int*, random_access_iterator<int*> >();
173     test<const int*, int*>();
174 
175 #if TEST_STD_VER >= 11
176     X x[3] = {X(1), X(2), X(3)};
177     Y y[3] = {Y(1), Y(2), Y(3)};
178     std::adjacent_difference(x, x+3, y, std::minus<X>());
179 #endif
180 
181 #if TEST_STD_VER > 17
182     test_use_move();
183 #endif // TEST_STD_VER > 17
184     // C++20 can use string in constexpr evaluation, but both libc++ and MSVC
185     // don't have the support yet. In these cases omit the constexpr test.
186     // FIXME Remove constexpr string workaround introduced in D90569
187 #if TEST_STD_VER > 17 && \
188 	(!defined(__cpp_lib_constexpr_string) || __cpp_lib_constexpr_string < 201907L)
189 	if (!std::is_constant_evaluated())
190 #endif
191     test_string();
192 
193     return true;
194 }
195 
196 int main(int, char**)
197 {
198     test();
199 #if TEST_STD_VER > 17
200     static_assert(test());
201 #endif
202     return 0;
203 }
204