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, class BinaryOperation>
17 //     OutputIterator
18 //     inclusive_scan(InputIterator first, InputIterator last,
19 //                    OutputIterator result,
20 //                    BinaryOperation binary_op); // C++17
21 
22 #include <numeric>
23 #include <algorithm>
24 #include <array>
25 #include <cassert>
26 #include <functional>
27 #include <iterator>
28 
29 #include "test_macros.h"
30 #include "test_iterators.h"
31 
32 template <class Iter1, class Op, class T>
33 TEST_CONSTEXPR_CXX20 void
34 test(Iter1 first, Iter1 last, Op op, const T *rFirst, const T *rLast)
35 {
36     assert((rLast - rFirst) <= 5);  // or else increase the size of "out"
37     T out[5];
38 
39     // Not in place
40     T *end = std::inclusive_scan(first, last, out, op);
41     assert(std::equal(out, end, rFirst, rLast));
42 
43     // In place
44     std::copy(first, last, out);
45     end = std::inclusive_scan(out, end, out, op);
46     assert(std::equal(out, end, rFirst, rLast));
47 }
48 
49 
50 template <class Iter>
51 TEST_CONSTEXPR_CXX20 void
52 test()
53 {
54     int ia[]         = {1, 3,  5,   7,   9};
55     const int pRes[] = {1, 4,  9,  16,  25};
56     const int mRes[] = {1, 3, 15, 105, 945};
57     const unsigned sa = sizeof(ia) / sizeof(ia[0]);
58     static_assert(sa == sizeof(pRes) / sizeof(pRes[0]));       // just to be sure
59     static_assert(sa == sizeof(mRes) / sizeof(mRes[0]));       // just to be sure
60 
61     for (unsigned int i = 0; i < sa; ++i ) {
62         test(Iter(ia), Iter(ia + i), std::plus<>(),       pRes, pRes + i);
63         test(Iter(ia), Iter(ia + i), std::multiplies<>(), mRes, mRes + i);
64     }
65 }
66 
67 constexpr size_t triangle(size_t n) { return n*(n+1)/2; }
68 
69 //  Basic sanity
70 TEST_CONSTEXPR_CXX20 void
71 basic_tests()
72 {
73     {
74     std::array<size_t, 10> v;
75     std::fill(v.begin(), v.end(), 3);
76     std::inclusive_scan(v.begin(), v.end(), v.begin(), std::plus<>());
77     for (size_t i = 0; i < v.size(); ++i)
78         assert(v[i] == (i+1) * 3);
79     }
80 
81     {
82     std::array<size_t, 10> v;
83     std::iota(v.begin(), v.end(), 0);
84     std::inclusive_scan(v.begin(), v.end(), v.begin(), std::plus<>());
85     for (size_t i = 0; i < v.size(); ++i)
86         assert(v[i] == triangle(i));
87     }
88 
89     {
90     std::array<size_t, 10> v;
91     std::iota(v.begin(), v.end(), 1);
92     std::inclusive_scan(v.begin(), v.end(), v.begin(), std::plus<>());
93     for (size_t i = 0; i < v.size(); ++i)
94         assert(v[i] == triangle(i + 1));
95     }
96 
97     {
98     std::array<size_t, 0> v, res;
99     std::inclusive_scan(v.begin(), v.end(), res.begin(), std::plus<>());
100     assert(res.empty());
101     }
102 }
103 
104 TEST_CONSTEXPR_CXX20 bool
105 test()
106 {
107     basic_tests();
108 
109 //  All the iterator categories
110     test<input_iterator        <const int*> >();
111     test<forward_iterator      <const int*> >();
112     test<bidirectional_iterator<const int*> >();
113     test<random_access_iterator<const int*> >();
114     test<const int*>();
115     test<      int*>();
116 
117     return true;
118 }
119 
120 int main(int, char**)
121 {
122     test();
123 #if TEST_STD_VER > 17
124     static_assert(test());
125 #endif
126     return 0;
127 }
128