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 
11 // <algorithm>
12 
13 // template<class ForwardIterator>
14 // constexpr ForwardIterator
15 //   shift_left(ForwardIterator first, ForwardIterator last,
16 //              typename iterator_traits<ForwardIterator>::difference_type n);
17 
18 #include <algorithm>
19 #include <cassert>
20 
21 #include "test_macros.h"
22 #include "test_iterators.h"
23 #include "MoveOnly.h"
24 
25 template<class T, class Iter>
26 constexpr bool test()
27 {
28     int orig[] = {3,1,4,1,5, 9,2,6,5,3, 5,8,9,7,9};
29     T work[] = {3,1,4,1,5, 9,2,6,5,3, 5,8,9,7,9};
30 
31     for (int n = 0; n <= 15; ++n) {
32         for (int k = 0; k <= n+2; ++k) {
33             std::copy(orig, orig+n, work);
34             Iter it = std::shift_left(Iter(work), Iter(work+n), k);
35             if (0 <= k && k < n) {
36                 assert(it == Iter(work+n-k));
37                 assert(std::equal(orig+k, orig+n, work, work+n-k));
38             } else {
39                 assert(it == Iter(work));
40                 assert(std::equal(orig, orig+n, work, work+n));
41             }
42         }
43     }
44 
45     // n == 0
46     {
47         T input[]          = { 0, 1, 2 };
48         const T expected[] = { 0, 1, 2 };
49         Iter b = Iter(std::begin(input));
50         Iter e = Iter(std::end(input));
51         Iter it = std::shift_left(b, e, 0);
52         assert(std::equal(std::begin(expected), std::end(expected), b, e));
53         assert(it == e);
54     }
55 
56     // n > 0 && n < len
57     {
58         T input[]          = { 0, 1, 2 };
59         const T expected[] = { 1, 2 };
60         Iter b = Iter(std::begin(input));
61         Iter e = Iter(std::end(input));
62         Iter it = std::shift_left(b, e, 1);
63         assert(std::equal(std::begin(expected), std::end(expected), b, it));
64     }
65     {
66         T input[]          = { 1, 2, 3, 4, 5, 6, 7, 8 };
67         const T expected[] = { 3, 4, 5, 6, 7, 8 };
68         Iter b = Iter(std::begin(input));
69         Iter e = Iter(std::end(input));
70         Iter it = std::shift_left(b, e, 2);
71         assert(std::equal(std::begin(expected), std::end(expected), b, it));
72     }
73     {
74         T input[]          = { 1, 2, 3, 4, 5, 6, 7, 8 };
75         const T expected[] = { 7, 8 };
76         Iter b = Iter(std::begin(input));
77         Iter e = Iter(std::end(input));
78         Iter it = std::shift_left(b, e, 6);
79         assert(std::equal(std::begin(expected), std::end(expected), b, it));
80     }
81 
82     // n == len
83     {
84         T input[]          = { 0, 1, 2 };
85         const T expected[] = { 0, 1, 2 };
86         Iter b = Iter(std::begin(input));
87         Iter e = Iter(std::end(input));
88         Iter it = std::shift_left(b, e, std::size(input));
89         assert(std::equal(std::begin(expected), std::end(expected), b, e));
90         assert(it == b);
91     }
92 
93     // n > len
94     {
95         T input[]          = { 0, 1, 2 };
96         const T expected[] = { 0, 1, 2 };
97         Iter b = Iter(std::begin(input));
98         Iter e = Iter(std::end(input));
99         Iter it = std::shift_left(b, e, std::size(input) + 1);
100         assert(std::equal(std::begin(expected), std::end(expected), b, e));
101         assert(it == b);
102     }
103 
104     return true;
105 }
106 
107 int main(int, char**)
108 {
109     test<int, forward_iterator<int*>>();
110     test<int, bidirectional_iterator<int*>>();
111     test<int, random_access_iterator<int*>>();
112     test<int, int*>();
113     test<MoveOnly, forward_iterator<MoveOnly*>>();
114     test<MoveOnly, bidirectional_iterator<MoveOnly*>>();
115     test<MoveOnly, random_access_iterator<MoveOnly*>>();
116     test<MoveOnly, MoveOnly*>();
117 
118     static_assert(test<int, forward_iterator<int*>>());
119     static_assert(test<int, bidirectional_iterator<int*>>());
120     static_assert(test<int, random_access_iterator<int*>>());
121     static_assert(test<int, int*>());
122     static_assert(test<MoveOnly, forward_iterator<MoveOnly*>>());
123     static_assert(test<MoveOnly, bidirectional_iterator<MoveOnly*>>());
124     static_assert(test<MoveOnly, random_access_iterator<MoveOnly*>>());
125     static_assert(test<MoveOnly, MoveOnly*>());
126 
127     return 0;
128 }
129