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 // <iterator>
10 
11 // reverse_iterator
12 
13 // template <RandomAccessIterator Iter1, RandomAccessIterator Iter2>
14 //   requires HasGreater<Iter1, Iter2>
15 // bool operator<(const reverse_iterator<Iter1>& x, const reverse_iterator<Iter2>& y); // constexpr in C++17
16 
17 #include <iterator>
18 #include <cassert>
19 
20 #include "test_macros.h"
21 #include "test_iterators.h"
22 
23 template <class It>
24 TEST_CONSTEXPR_CXX17 void test(It l, It r, bool x) {
25     const std::reverse_iterator<It> r1(l);
26     const std::reverse_iterator<It> r2(r);
27     assert((r1 < r2) == x);
28 }
29 
30 TEST_CONSTEXPR_CXX17 bool tests() {
31     const char* s = "1234567890";
32     test(random_access_iterator<const char*>(s), random_access_iterator<const char*>(s), false);
33     test(random_access_iterator<const char*>(s), random_access_iterator<const char*>(s+1), false);
34     test(random_access_iterator<const char*>(s+1), random_access_iterator<const char*>(s), true);
35 #if TEST_STD_VER >= 20
36     test(cpp20_random_access_iterator<const char*>(s), cpp20_random_access_iterator<const char*>(s), false);
37     test(cpp20_random_access_iterator<const char*>(s), cpp20_random_access_iterator<const char*>(s + 1), false);
38     test(cpp20_random_access_iterator<const char*>(s + 1), cpp20_random_access_iterator<const char*>(s), true);
39 #endif
40     test(s, s, false);
41     test(s, s+1, false);
42     test(s+1, s, true);
43     return true;
44 }
45 
46 int main(int, char**) {
47     tests();
48 #if TEST_STD_VER > 14
49     static_assert(tests(), "");
50 #endif
51     return 0;
52 }
53