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
10 // UNSUPPORTED: clang-8
11 // UNSUPPORTED: gcc-9
12 
13 // <numeric>
14 
15 // Became constexpr in C++20
16 // template<class InputIterator, class OutputIterator, class T>
17 //     OutputIterator inclusive_scan(InputIterator first, InputIterator last,
18 //                                   OutputIterator result, T init);
19 //
20 
21 #include <numeric>
22 #include <algorithm>
23 #include <array>
24 #include <cassert>
25 #include <functional>
26 #include <iterator>
27 
28 #include "test_macros.h"
29 #include "test_iterators.h"
30 
31 template <class Iter1, class T>
32 TEST_CONSTEXPR_CXX20 void
33 test(Iter1 first, Iter1 last, const T *rFirst, const T *rLast)
34 {
35     assert((rLast - rFirst) <= 5);  // or else increase the size of "out"
36     T out[5];
37 
38     // Not in place
39     T *end = std::inclusive_scan(first, last, out);
40     assert(std::equal(out, end, rFirst, rLast));
41 
42     // In place
43     std::copy(first, last, out);
44     end = std::inclusive_scan(out, end, out);
45     assert(std::equal(out, end, rFirst, rLast));
46 }
47 
48 
49 template <class Iter>
50 TEST_CONSTEXPR_CXX20 void
51 test()
52 {
53     int ia[]         = {1, 3, 5, 7,  9};
54     const int pRes[] = {1, 4, 9, 16, 25};
55     const unsigned sa = sizeof(ia) / sizeof(ia[0]);
56     static_assert(sa == sizeof(pRes) / sizeof(pRes[0]));       // just to be sure
57 
58     for (unsigned int i = 0; i < sa; ++i ) {
59         test(Iter(ia), Iter(ia + i), pRes, pRes + i);
60     }
61 }
62 
63 constexpr size_t triangle(size_t n) { return n*(n+1)/2; }
64 
65 //  Basic sanity
66 TEST_CONSTEXPR_CXX20 void
67 basic_tests()
68 {
69     {
70     std::array<size_t, 10> v;
71     std::fill(v.begin(), v.end(), 3);
72     std::inclusive_scan(v.begin(), v.end(), v.begin());
73     for (size_t i = 0; i < v.size(); ++i)
74         assert(v[i] == (i+1) * 3);
75     }
76 
77     {
78     std::array<size_t, 10> v;
79     std::iota(v.begin(), v.end(), 0);
80     std::inclusive_scan(v.begin(), v.end(), v.begin());
81     for (size_t i = 0; i < v.size(); ++i)
82         assert(v[i] == triangle(i));
83     }
84 
85     {
86     std::array<size_t, 10> v;
87     std::iota(v.begin(), v.end(), 1);
88     std::inclusive_scan(v.begin(), v.end(), v.begin());
89     for (size_t i = 0; i < v.size(); ++i)
90         assert(v[i] == triangle(i + 1));
91     }
92 
93     {
94     std::array<size_t, 0> v, res;
95     std::inclusive_scan(v.begin(), v.end(), res.begin());
96     assert(res.empty());
97     }
98 }
99 
100 TEST_CONSTEXPR_CXX20 bool
101 test()
102 {
103     basic_tests();
104 
105 //  All the iterator categories
106     test<input_iterator        <const int*> >();
107     test<forward_iterator      <const int*> >();
108     test<bidirectional_iterator<const int*> >();
109     test<random_access_iterator<const int*> >();
110     test<const int*>();
111     test<      int*>();
112 
113     return true;
114 }
115 
116 int main(int, char**)
117 {
118     test();
119 #if TEST_STD_VER > 17
120     static_assert(test());
121 #endif
122     return 0;
123 }
124