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
11 // <numeric>
12
13 // Became constexpr in C++20
14 // template<class InputIterator, class OutputIterator, class T>
15 // OutputIterator exclusive_scan(InputIterator first, InputIterator last,
16 // OutputIterator result, T init);
17 //
18
19 #include <numeric>
20 #include <algorithm>
21 #include <array>
22 #include <cassert>
23 #include <functional>
24 #include <iterator>
25
26 #include "test_macros.h"
27 #include "test_iterators.h"
28
29 template <class Iter1, class T>
30 TEST_CONSTEXPR_CXX20 void
test(Iter1 first,Iter1 last,T init,const T * rFirst,const T * rLast)31 test(Iter1 first, Iter1 last, T init, const T *rFirst, const T *rLast)
32 {
33 assert((rLast - rFirst) <= 5); // or else increase the size of "out"
34 T out[5];
35
36 // Not in place
37 T *end = std::exclusive_scan(first, last, out, init);
38 assert(std::equal(out, end, rFirst, rLast));
39
40 // In place
41 std::copy(first, last, out);
42 end = std::exclusive_scan(out, end, out, init);
43 assert(std::equal(out, end, rFirst, rLast));
44 }
45
46 template <class Iter>
47 TEST_CONSTEXPR_CXX20 void
test()48 test()
49 {
50 int ia[] = {1, 3, 5, 7, 9};
51 const int pRes[] = {0, 1, 4, 9, 16};
52 const unsigned sa = sizeof(ia) / sizeof(ia[0]);
53 static_assert(sa == sizeof(pRes) / sizeof(pRes[0])); // just to be sure
54
55 for (unsigned int i = 0; i < sa; ++i) {
56 test(Iter(ia), Iter(ia + i), 0, pRes, pRes + i);
57 }
58 }
59
triangle(size_t n)60 constexpr size_t triangle(size_t n) { return n*(n+1)/2; }
61
62 // Basic sanity
63 TEST_CONSTEXPR_CXX20 void
basic_tests()64 basic_tests()
65 {
66 {
67 std::array<size_t, 10> v;
68 std::fill(v.begin(), v.end(), 3);
69 std::exclusive_scan(v.begin(), v.end(), v.begin(), size_t{50});
70 for (size_t i = 0; i < v.size(); ++i)
71 assert(v[i] == 50 + i * 3);
72 }
73
74 {
75 std::array<size_t, 10> v;
76 std::iota(v.begin(), v.end(), 0);
77 std::exclusive_scan(v.begin(), v.end(), v.begin(), size_t{30});
78 for (size_t i = 0; i < v.size(); ++i)
79 assert(v[i] == 30 + triangle(i-1));
80 }
81
82 {
83 std::array<size_t, 10> v;
84 std::iota(v.begin(), v.end(), 1);
85 std::exclusive_scan(v.begin(), v.end(), v.begin(), size_t{40});
86 for (size_t i = 0; i < v.size(); ++i)
87 assert(v[i] == 40 + triangle(i));
88 }
89
90 }
91
92 TEST_CONSTEXPR_CXX20 bool
test()93 test()
94 {
95 basic_tests();
96
97 // All the iterator categories
98 test<cpp17_input_iterator <const int*> >();
99 test<forward_iterator <const int*> >();
100 test<bidirectional_iterator<const int*> >();
101 test<random_access_iterator<const int*> >();
102 test<const int*>();
103 test< int*>();
104
105 return true;
106 }
107
main(int,char **)108 int main(int, char**)
109 {
110 test();
111 #if TEST_STD_VER > 17
112 static_assert(test());
113 #endif
114 return 0;
115 }
116