1/*
2 * Copyright 2016-present Facebook, Inc.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <map>
18
19#include <folly/container/Array.h>
20#include <folly/detail/Iterators.h>
21#include <folly/portability/GTest.h>
22
23using namespace folly::detail;
24using namespace folly;
25
26namespace {
27struct IntArrayIterator
28 : IteratorFacade<IntArrayIterator, int const, std::forward_iterator_tag> {
29 explicit IntArrayIterator(int const* a) : a_(a) {}
30 void increment() {
31 ++a_;
32 }
33 int const& dereference() const {
34 return *a_;
35 }
36 bool equal(IntArrayIterator const& rhs) const {
37 return rhs.a_ == a_;
38 }
39 int const* a_;
40};
41} // namespace
42
43TEST(IteratorsTest, IterFacadeHasCorrectTraits) {
44 using TR = std::iterator_traits<IntArrayIterator>;
45 static_assert(std::is_same<TR::value_type, int const>::value, "");
46 static_assert(std::is_same<TR::reference, int const&>::value, "");
47 static_assert(std::is_same<TR::pointer, int const*>::value, "");
48 static_assert(
49 std::is_same<TR::iterator_category, std::forward_iterator_tag>::value,
50 "");
51 static_assert(std::is_same<TR::difference_type, ssize_t>::value, "");
52}
53
54TEST(IteratorsTest, SimpleIteratorFacade) {
55 static const auto kArray = folly::make_array(42, 43, 44);
56 IntArrayIterator end(kArray.data() + kArray.size());
57 IntArrayIterator iter(kArray.data());
58 EXPECT_NE(iter, end);
59 EXPECT_EQ(42, *iter);
60 ++iter;
61 EXPECT_NE(iter, end);
62 EXPECT_EQ(43, *iter);
63 ++iter;
64 EXPECT_NE(iter, end);
65 EXPECT_EQ(44, *iter);
66 ++iter;
67 EXPECT_EQ(iter, end);
68}
69
70namespace {
71// Simple iterator adaptor: wraps an int pointer.
72struct IntPointerIter : IteratorAdaptor<
73 IntPointerIter,
74 int const*,
75 int const,
76 std::forward_iterator_tag> {
77 using Super = IteratorAdaptor<
78 IntPointerIter,
79 int const*,
80 int const,
81 std::forward_iterator_tag>;
82 explicit IntPointerIter(int const* ptr) : Super(ptr) {}
83};
84} // namespace
85
86TEST(IteratorsTest, IterAdaptorHasCorrectTraits) {
87 using TR = std::iterator_traits<IntPointerIter>;
88 static_assert(std::is_same<TR::value_type, int const>::value, "");
89 static_assert(std::is_same<TR::reference, int const&>::value, "");
90 static_assert(std::is_same<TR::pointer, int const*>::value, "");
91 static_assert(
92 std::is_same<TR::iterator_category, std::forward_iterator_tag>::value,
93 "");
94 static_assert(std::is_same<TR::difference_type, ssize_t>::value, "");
95}
96
97TEST(IteratorsTest, IterAdaptorWithPointer) {
98 static const auto kArray = folly::make_array(42, 43, 44);
99 IntPointerIter end(kArray.data() + kArray.size());
100 IntPointerIter iter(kArray.data());
101 EXPECT_NE(iter, end);
102 EXPECT_EQ(42, *iter);
103 ++iter;
104 EXPECT_NE(iter, end);
105 EXPECT_EQ(43, *iter);
106 ++iter;
107 EXPECT_NE(iter, end);
108 EXPECT_EQ(44, *iter);
109 ++iter;
110 EXPECT_EQ(iter, end);
111}
112
113namespace {
114// More complex case: wrap a map iterator, but these provide either the key or
115// value.
116struct IntMapKeyIter : IteratorAdaptor<
117 IntMapKeyIter,
118 std::map<int, int>::iterator,
119 int const,
120 std::forward_iterator_tag> {
121 using Super = IteratorAdaptor<
122 IntMapKeyIter,
123 std::map<int, int>::iterator,
124 int const,
125 std::forward_iterator_tag>;
126 explicit IntMapKeyIter(std::map<int, int>::iterator iter) : Super(iter) {}
127 int const& dereference() const {
128 return base()->first;
129 }
130};
131
132struct IntMapValueIter : IteratorAdaptor<
133 IntMapValueIter,
134 std::map<int, int>::iterator,
135 int,
136 std::forward_iterator_tag> {
137 using Super = IteratorAdaptor<
138 IntMapValueIter,
139 std::map<int, int>::iterator,
140 int,
141 std::forward_iterator_tag>;
142 explicit IntMapValueIter(std::map<int, int>::iterator iter) : Super(iter) {}
143 int& dereference() const {
144 return base()->second;
145 }
146};
147
148} // namespace
149
150TEST(IteratorsTest, IterAdaptorOfOtherIter) {
151 std::map<int, int> m{{2, 42}, {3, 43}, {4, 44}};
152
153 IntMapKeyIter keyEnd(m.end());
154 IntMapKeyIter keyIter(m.begin());
155 EXPECT_NE(keyIter, keyEnd);
156 EXPECT_EQ(2, *keyIter);
157 ++keyIter;
158 EXPECT_NE(keyIter, keyEnd);
159 EXPECT_EQ(3, *keyIter);
160 ++keyIter;
161 EXPECT_NE(keyIter, keyEnd);
162 EXPECT_EQ(4, *keyIter);
163 ++keyIter;
164 EXPECT_EQ(keyIter, keyEnd);
165
166 IntMapValueIter valueEnd(m.end());
167 IntMapValueIter valueIter(m.begin());
168 EXPECT_NE(valueIter, valueEnd);
169 EXPECT_EQ(42, *valueIter);
170 ++valueIter;
171 EXPECT_NE(valueIter, valueEnd);
172 EXPECT_EQ(43, *valueIter);
173 ++valueIter;
174 EXPECT_NE(valueIter, valueEnd);
175 EXPECT_EQ(44, *valueIter);
176 ++valueIter;
177 EXPECT_EQ(valueIter, valueEnd);
178}
179
180namespace {
181struct IntMapValueIterConst : IteratorAdaptor<
182 IntMapValueIterConst,
183 std::map<int, int>::const_iterator,
184 int const,
185 std::forward_iterator_tag> {
186 using Super = IteratorAdaptor<
187 IntMapValueIterConst,
188 std::map<int, int>::const_iterator,
189 int const,
190 std::forward_iterator_tag>;
191 explicit IntMapValueIterConst(std::map<int, int>::const_iterator iter)
192 : Super(iter) {}
193 /* implicit */ IntMapValueIterConst(IntMapValueIter const& rhs)
194 : IntMapValueIterConst(rhs.base()) {}
195 int const& dereference() const {
196 return base()->second;
197 }
198};
199} // namespace
200
201TEST(IteratorsTest, MixedConstAndNonconstIters) {
202 std::map<int, int> m{{2, 42}, {3, 43}, {4, 44}};
203 IntMapValueIterConst cend(m.cend());
204 IntMapValueIter valueIter(m.begin());
205 EXPECT_NE(valueIter, cend);
206 ++valueIter;
207 ++valueIter;
208 ++valueIter;
209 EXPECT_EQ(valueIter, cend);
210}
211