1 /*
2 * Copyright (C) 2017 The Android Open Source Project
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
18 #ifndef ANDROID_VINTF_MAP_VALUE_ITERATOR_H
19 #define ANDROID_VINTF_MAP_VALUE_ITERATOR_H
20
21 #include <iterator>
22 #include <map>
23
24 namespace android {
25 namespace vintf {
26
27 template<typename Map>
28 struct MapIterTypes {
29 using K = typename Map::key_type;
30 using V = typename Map::mapped_type;
31
32 // Iterator over all values of a Map
33 template<bool is_const>
34 struct IteratorImpl
35 {
36 using iterator_category = std::bidirectional_iterator_tag;
37 using value_type = V;
38 using difference_type = ptrdiff_t;
39 using pointer = typename std::conditional<is_const, const V *, V *>::type;
40 using reference = typename std::conditional<is_const, const V &, V &>::type;
41
42 using map_iter = typename std::conditional<is_const,
43 typename Map::const_iterator, typename Map::iterator>::type;
44
IteratorImplMapIterTypes::IteratorImpl45 IteratorImpl(map_iter i) : mIter(i) {}
46
47 inline IteratorImpl &operator++() {
48 mIter++;
49 return *this;
50 }
51 inline IteratorImpl operator++(int) {
52 IteratorImpl i = *this;
53 mIter++;
54 return i;
55 }
56 inline IteratorImpl &operator--() {
57 mIter--;
58 return *this;
59 }
60 inline IteratorImpl operator--(int) {
61 IteratorImpl i = *this;
62 mIter--;
63 return i;
64 }
65 inline reference operator*() const { return mIter->second; }
66 inline pointer operator->() const { return &(mIter->second); }
67 inline bool operator==(const IteratorImpl &rhs) const { return mIter == rhs.mIter; }
68 inline bool operator!=(const IteratorImpl &rhs) const { return mIter != rhs.mIter; }
69
70 private:
71 map_iter mIter;
72 };
73
74 using ValueIterator = IteratorImpl<false>;
75 using ConstValueIterator = IteratorImpl<true>;
76
77 template<bool is_const>
78 struct IterableImpl {
79 using map_ref = typename std::conditional<is_const, const Map &, Map &>::type;
IterableImplMapIterTypes::IterableImpl80 IterableImpl(map_ref map) : mMap(map) {}
81
beginMapIterTypes::IterableImpl82 IteratorImpl<is_const> begin() const {
83 return IteratorImpl<is_const>(mMap.begin());
84 }
85
endMapIterTypes::IterableImpl86 IteratorImpl<is_const> end() const {
87 return IteratorImpl<is_const>(mMap.end());
88 }
89
emptyMapIterTypes::IterableImpl90 bool empty() const { return begin() == end(); }
91
92 private:
93 map_ref mMap;
94 };
95
96 template <bool is_const>
97 struct RangeImpl {
98 using iter_type = typename std::conditional<is_const, typename Map::const_iterator,
99 typename Map::iterator>::type;
100 using range_type = std::pair<iter_type, iter_type>;
RangeImplMapIterTypes::RangeImpl101 RangeImpl(range_type r) : mRange(r) {}
beginMapIterTypes::RangeImpl102 IteratorImpl<is_const> begin() const { return mRange.first; }
endMapIterTypes::RangeImpl103 IteratorImpl<is_const> end() const { return mRange.second; }
emptyMapIterTypes::RangeImpl104 bool empty() const { return begin() == end(); }
105
106 private:
107 range_type mRange;
108 };
109
110 using ValueIterable = IterableImpl<false>;
111 using ConstValueIterable = IterableImpl<true>;
112 };
113
114 template<typename K, typename V>
115 using ConstMapValueIterable = typename MapIterTypes<std::map<K, V>>::ConstValueIterable;
116 template<typename K, typename V>
117 using ConstMultiMapValueIterable = typename MapIterTypes<std::multimap<K, V>>::ConstValueIterable;
118 template <typename K, typename V>
119 using MapValueIterable = typename MapIterTypes<std::map<K, V>>::ValueIterable;
120 template <typename K, typename V>
121 using MultiMapValueIterable = typename MapIterTypes<std::multimap<K, V>>::ValueIterable;
122
123 template<typename K, typename V>
iterateValues(const std::map<K,V> & map)124 ConstMapValueIterable<K, V> iterateValues(const std::map<K, V> &map) {
125 return map;
126 }
127 template<typename K, typename V>
iterateValues(const std::multimap<K,V> & map)128 ConstMultiMapValueIterable<K, V> iterateValues(const std::multimap<K, V> &map) {
129 return map;
130 }
131 template <typename K, typename V>
iterateValues(std::map<K,V> & map)132 MapValueIterable<K, V> iterateValues(std::map<K, V>& map) {
133 return map;
134 }
135 template <typename K, typename V>
iterateValues(std::multimap<K,V> & map)136 MultiMapValueIterable<K, V> iterateValues(std::multimap<K, V>& map) {
137 return map;
138 }
139
140 template <typename K, typename V>
iterateValues(const std::multimap<K,V> & map,const K & key)141 typename MapIterTypes<std::multimap<K, V>>::template RangeImpl<true> iterateValues(
142 const std::multimap<K, V>& map, const K& key) {
143 return map.equal_range(key);
144 }
145
146 } // namespace vintf
147 } // namespace android
148
149 #endif // ANDROID_VINTF_MAP_VALUE_ITERATOR_H
150