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, c++17
10 // UNSUPPORTED: libcpp-has-no-incomplete-ranges
11
12 // ranges::advance(it, n)
13
14 #include <iterator>
15
16 #include <cassert>
17
18 #include "test_iterators.h"
19 #include "test_macros.h"
20
21 template <bool Count, typename It>
check(int * first,std::iter_difference_t<It> n,int * expected)22 constexpr void check(int* first, std::iter_difference_t<It> n, int* expected) {
23 using Difference = std::iter_difference_t<It>;
24 Difference const M = (expected - first); // expected travel distance (which may be negative)
25 auto abs = [](auto x) { return x < 0 ? -x : x; };
26
27 {
28 It it(first);
29 std::ranges::advance(it, n);
30 assert(base(it) == expected);
31 ASSERT_SAME_TYPE(decltype(std::ranges::advance(it, n)), void);
32 }
33
34 // Count operations
35 if constexpr (Count) {
36 auto it = stride_counting_iterator(It(first));
37 std::ranges::advance(it, n);
38 if constexpr (std::random_access_iterator<It>) {
39 assert(it.stride_count() <= 1);
40 } else {
41 assert(it.stride_count() == abs(M));
42 }
43 }
44 }
45
test()46 constexpr bool test() {
47 int range[] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
48
49 // Check advancing forward
50 for (int n = 0; n != 10; ++n) {
51 check<false, cpp17_input_iterator<int*>>( range, n, range+n);
52 check<false, cpp20_input_iterator<int*>>( range, n, range+n);
53 check<true, forward_iterator<int*>>( range, n, range+n);
54 check<true, bidirectional_iterator<int*>>(range, n, range+n);
55 check<true, random_access_iterator<int*>>(range, n, range+n);
56 check<true, contiguous_iterator<int*>>( range, n, range+n);
57 check<true, int*>( range, n, range+n);
58 check<true, cpp17_output_iterator<int*> >(range, n, range+n);
59 }
60
61 // Check advancing backward
62 for (int n = 0; n != 10; ++n) {
63 check<true, bidirectional_iterator<int*>>(range+9, -n, range+9 - n);
64 check<true, random_access_iterator<int*>>(range+9, -n, range+9 - n);
65 check<true, contiguous_iterator<int*>>( range+9, -n, range+9 - n);
66 check<true, int*>( range+9, -n, range+9 - n);
67 }
68
69 return true;
70 }
71
main(int,char **)72 int main(int, char**) {
73 assert(test());
74 static_assert(test());
75 return 0;
76 }
77