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 && !stdlib=libc++
10
11// <algorithm>
12
13// template<BidirectionalIterator InIter, BidirectionalIterator OutIter>
14// requires OutputIterator<OutIter, RvalueOf<InIter::reference>::type>
15// OutIter
16// move_backward(InIter first, InIter last, OutIter result);
17
18#include <algorithm>
19#include <cassert>
20#include <iterator>
21#include <memory>
22#include <vector>
23
24#include "MoveOnly.h"
25#include "test_iterators.h"
26#include "test_macros.h"
27#include "type_algorithms.h"
28
29class PaddedBase {
30public:
31 TEST_CONSTEXPR PaddedBase(std::int16_t a, std::int8_t b) : a_(a), b_(b) {}
32
33 std::int16_t a_;
34 std::int8_t b_;
35};
36
37class Derived : public PaddedBase {
38public:
39 TEST_CONSTEXPR Derived(std::int16_t a, std::int8_t b, std::int8_t c) : PaddedBase(a, b), c_(c) {}
40
41 std::int8_t c_;
42};
43
44template <class InIter>
45struct Test {
46 template <class OutIter>
47 TEST_CONSTEXPR_CXX20 void operator()() {
48 const unsigned N = 1000;
49 int ia[N] = {};
50 for (unsigned i = 0; i < N; ++i)
51 ia[i] = i;
52 int ib[N] = {0};
53
54 OutIter r = std::move_backward(InIter(ia), InIter(ia + N), OutIter(ib + N));
55 assert(base(r) == ib);
56 for (unsigned i = 0; i < N; ++i)
57 assert(ia[i] == ib[i]);
58 }
59};
60
61struct TestOutIters {
62 template <class InIter>
63 TEST_CONSTEXPR_CXX20 void operator()() {
64 types::for_each(types::concatenate_t<types::bidirectional_iterator_list<int*> >(), Test<InIter>());
65 }
66};
67
68template <class InIter>
69struct Test1 {
70 template <class OutIter>
71 TEST_CONSTEXPR_CXX23 void operator()() {
72 const unsigned N = 100;
73 std::unique_ptr<int> ia[N];
74 for (unsigned i = 0; i < N; ++i)
75 ia[i].reset(p: new int(i));
76 std::unique_ptr<int> ib[N];
77
78 OutIter r = std::move_backward(InIter(ia), InIter(ia + N), OutIter(ib + N));
79 assert(base(r) == ib);
80 for (unsigned i = 0; i < N; ++i)
81 assert(*ib[i] == static_cast<int>(i));
82 }
83};
84
85struct Test1OutIters {
86 template <class InIter>
87 TEST_CONSTEXPR_CXX23 void operator()() {
88 types::for_each(
89 types::concatenate_t<types::bidirectional_iterator_list<std::unique_ptr<int>*> >(), Test1<InIter>());
90 }
91};
92
93TEST_CONSTEXPR_CXX20 bool test_vector_bool(std::size_t N) {
94 std::vector<bool> v(N, false);
95 for (std::size_t i = 0; i < N; i += 2)
96 v[i] = true;
97
98 { // Test move_backward with aligned bytes
99 std::vector<bool> in(v);
100 std::vector<bool> out(N);
101 std::move_backward(first: in.begin(), last: in.end(), result: out.end());
102 assert(out == v);
103 }
104 { // Test move_backward with unaligned bytes
105 std::vector<bool> in(v);
106 std::vector<bool> out(N);
107 std::move_backward(first: in.begin(), last: in.end() - 4, result: out.end());
108 for (std::size_t i = 0; i < N - 4; ++i)
109 assert(out[i + 4] == v[i]);
110 }
111
112 return true;
113}
114
115TEST_CONSTEXPR_CXX20 bool test() {
116 types::for_each(types::bidirectional_iterator_list<int*>(), TestOutIters());
117 if (TEST_STD_AT_LEAST_23_OR_RUNTIME_EVALUATED)
118 types::for_each(types::bidirectional_iterator_list<std::unique_ptr<int>*>(), Test1OutIters());
119 { // Make sure that padding bits aren't copied
120 Derived src(1, 2, 3);
121 Derived dst(4, 5, 6);
122 std::move_backward(
123 first: static_cast<PaddedBase*>(&src), last: static_cast<PaddedBase*>(&src) + 1, result: static_cast<PaddedBase*>(&dst) + 1);
124 assert(dst.a_ == 1);
125 assert(dst.b_ == 2);
126 assert(dst.c_ == 6);
127 }
128 { // Make sure that overlapping ranges can be copied
129 int a[] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
130 std::move_backward(first: a, last: a + 7, result: a + 10);
131 int expected[] = {1, 2, 3, 1, 2, 3, 4, 5, 6, 7};
132 assert(std::equal(a, a + 10, expected));
133 }
134 { // Make sure that the algorithm works with move-only types
135 // When non-trivial
136 {
137 MoveOnly from[3] = {1, 2, 3};
138 MoveOnly to[3] = {};
139 std::move_backward(std::begin(from), std::end(from), std::end(to));
140 assert(to[0] == MoveOnly(1));
141 assert(to[1] == MoveOnly(2));
142 assert(to[2] == MoveOnly(3));
143 }
144 // When trivial
145 {
146 TrivialMoveOnly from[3] = {1, 2, 3};
147 TrivialMoveOnly to[3] = {};
148 std::move_backward(std::begin(from), std::end(from), std::end(to));
149 assert(to[0] == TrivialMoveOnly(1));
150 assert(to[1] == TrivialMoveOnly(2));
151 assert(to[2] == TrivialMoveOnly(3));
152 }
153 }
154
155 { // Test vector<bool>::iterator optimization
156 assert(test_vector_bool(8));
157 assert(test_vector_bool(19));
158 assert(test_vector_bool(32));
159 assert(test_vector_bool(49));
160 assert(test_vector_bool(64));
161 assert(test_vector_bool(199));
162 assert(test_vector_bool(256));
163 }
164
165 return true;
166}
167
168int main(int, char**) {
169 test();
170#if TEST_STD_VER >= 20
171 static_assert(test());
172#endif
173
174 return 0;
175}
176

source code of libcxx/test/std/algorithms/alg.modifying.operations/alg.move/move_backward.pass.cpp