2 * Copyright 2016 Facebook, Inc.
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
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
16 // Copyright 2013-present Facebook. All Rights Reserved.
17 // @author: Pavlo Kushnir (pavlo)
21 #include <initializer_list>
24 #include <folly/Range.h>
25 #include <folly/experimental/StringKeyedCommon.h>
30 * Wrapper class for map<string, Value> that can
31 * perform lookup operations with StringPiece, not only string.
33 * It uses kind of hack: string pointed by StringPiece is copied when
34 * StringPiece is inserted into map
36 template <class Value,
37 class Compare = std::less<StringPiece>,
38 class Alloc = std::allocator<std::pair<const StringPiece, Value>>>
40 : private std::map<StringPiece, Value, Compare, Alloc> {
42 using Base = std::map<StringPiece, Value, Compare, Alloc>;
45 typedef typename Base::key_type key_type;
46 typedef typename Base::mapped_type mapped_type;
47 typedef typename Base::value_type value_type;
48 typedef typename Base::key_compare key_compare;
49 typedef typename Base::allocator_type allocator_type;
50 typedef typename Base::reference reference;
51 typedef typename Base::const_reference const_reference;
52 typedef typename Base::pointer pointer;
53 typedef typename Base::const_pointer const_pointer;
54 typedef typename Base::iterator iterator;
55 typedef typename Base::const_iterator const_iterator;
56 typedef typename Base::reverse_iterator reverse_iterator;
57 typedef typename Base::const_reverse_iterator const_reverse_iterator;
58 typedef typename Base::difference_type difference_type;
59 typedef typename Base::size_type size_type;
61 using Base::get_allocator;
63 // Ctors in the same order as
64 // http://cplusplus.com/reference/map/map/map/
65 explicit StringKeyedMap(
66 const key_compare& comp = key_compare(),
67 const allocator_type& alloc = allocator_type())
71 explicit StringKeyedMap(const allocator_type& alloc)
75 template <class InputIterator>
76 explicit StringKeyedMap(
77 InputIterator b, InputIterator e,
78 const key_compare& comp = key_compare(),
79 const allocator_type& alloc = allocator_type())
82 // emplace() will carry the duplication
83 emplace(b->first, b->second);
87 StringKeyedMap(const StringKeyedMap& rhs)
88 : StringKeyedMap(rhs, rhs.get_allocator()) {
91 StringKeyedMap(const StringKeyedMap& rhs, const allocator_type& a)
92 : StringKeyedMap(rhs.begin(), rhs.end(), rhs.key_comp(), a) {
95 StringKeyedMap(StringKeyedMap&& other) noexcept
96 : Base(std::move(other)) {
99 StringKeyedMap(StringKeyedMap&& other, const allocator_type& /* a */) noexcept
100 : Base(std::move(other) /*, a*/ /* not supported by gcc */) {}
102 StringKeyedMap(std::initializer_list<value_type> il,
103 const key_compare& comp = key_compare(),
104 const allocator_type& alloc = allocator_type())
105 : StringKeyedMap(il.begin(), il.end(), comp, alloc) {
108 StringKeyedMap& operator=(const StringKeyedMap& other) & {
109 if (this == &other) {
112 return *this = StringKeyedMap(other);
115 StringKeyedMap& operator=(StringKeyedMap&& other) & noexcept {
116 assert(this != &other);
118 Base::operator=(std::move(other));
124 using Base::max_size;
134 // no need for copy/move overload as StringPiece is small struct
135 mapped_type& operator[](StringPiece key) {
140 // operator[] will create new (key, value) pair
141 // we need to allocate memory for key
142 return Base::operator[](stringPieceDup(key, get_allocator()));
147 using Base::lower_bound;
148 using Base::upper_bound;
150 template <class... Args>
151 std::pair<iterator, bool> emplace(StringPiece key, Args&&... args) {
156 return Base::emplace(stringPieceDup(key, get_allocator()),
157 std::forward<Args>(args)...);
160 std::pair<iterator, bool> insert(value_type val) {
161 auto it = find(val.first);
166 std::make_pair(stringPieceDup(val.first, get_allocator()),
167 std::move(val.second)));
170 iterator erase(const_iterator position) {
171 auto key = position->first;
172 auto result = Base::erase(position);
173 stringPieceDel(key, get_allocator());
177 size_type erase(StringPiece key) {
186 void clear() noexcept {
187 for (auto& it : *this) {
188 stringPieceDel(it.first, get_allocator());
194 // Here we assume that map doesn't use keys in destructor
195 for (auto& it : *this) {
196 stringPieceDel(it.first, get_allocator());