/src/abseil-cpp/absl/container/flat_hash_map.h
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1 | | // Copyright 2018 The Abseil Authors. |
2 | | // |
3 | | // Licensed under the Apache License, Version 2.0 (the "License"); |
4 | | // you may not use this file except in compliance with the License. |
5 | | // You may obtain a copy of the License at |
6 | | // |
7 | | // https://www.apache.org/licenses/LICENSE-2.0 |
8 | | // |
9 | | // Unless required by applicable law or agreed to in writing, software |
10 | | // distributed under the License is distributed on an "AS IS" BASIS, |
11 | | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
12 | | // See the License for the specific language governing permissions and |
13 | | // limitations under the License. |
14 | | // |
15 | | // ----------------------------------------------------------------------------- |
16 | | // File: flat_hash_map.h |
17 | | // ----------------------------------------------------------------------------- |
18 | | // |
19 | | // An `absl::flat_hash_map<K, V>` is an unordered associative container of |
20 | | // unique keys and associated values designed to be a more efficient replacement |
21 | | // for `std::unordered_map`. Like `unordered_map`, search, insertion, and |
22 | | // deletion of map elements can be done as an `O(1)` operation. However, |
23 | | // `flat_hash_map` (and other unordered associative containers known as the |
24 | | // collection of Abseil "Swiss tables") contain other optimizations that result |
25 | | // in both memory and computation advantages. |
26 | | // |
27 | | // In most cases, your default choice for a hash map should be a map of type |
28 | | // `flat_hash_map`. |
29 | | // |
30 | | // `flat_hash_map` is not exception-safe. |
31 | | |
32 | | #ifndef ABSL_CONTAINER_FLAT_HASH_MAP_H_ |
33 | | #define ABSL_CONTAINER_FLAT_HASH_MAP_H_ |
34 | | |
35 | | #include <cstddef> |
36 | | #include <memory> |
37 | | #include <type_traits> |
38 | | #include <utility> |
39 | | |
40 | | #include "absl/algorithm/container.h" |
41 | | #include "absl/base/attributes.h" |
42 | | #include "absl/base/macros.h" |
43 | | #include "absl/container/hash_container_defaults.h" |
44 | | #include "absl/container/internal/container_memory.h" |
45 | | #include "absl/container/internal/raw_hash_map.h" // IWYU pragma: export |
46 | | #include "absl/meta/type_traits.h" |
47 | | |
48 | | namespace absl { |
49 | | ABSL_NAMESPACE_BEGIN |
50 | | namespace container_internal { |
51 | | template <class K, class V> |
52 | | struct FlatHashMapPolicy; |
53 | | } // namespace container_internal |
54 | | |
55 | | // ----------------------------------------------------------------------------- |
56 | | // absl::flat_hash_map |
57 | | // ----------------------------------------------------------------------------- |
58 | | // |
59 | | // An `absl::flat_hash_map<K, V>` is an unordered associative container which |
60 | | // has been optimized for both speed and memory footprint in most common use |
61 | | // cases. Its interface is similar to that of `std::unordered_map<K, V>` with |
62 | | // the following notable differences: |
63 | | // |
64 | | // * Requires keys that are CopyConstructible |
65 | | // * Requires values that are MoveConstructible |
66 | | // * Supports heterogeneous lookup, through `find()`, `operator[]()` and |
67 | | // `insert()`, provided that the map is provided a compatible heterogeneous |
68 | | // hashing function and equality operator. See below for details. |
69 | | // * Invalidates any references and pointers to elements within the table after |
70 | | // `rehash()` and when the table is moved. |
71 | | // * Contains a `capacity()` member function indicating the number of element |
72 | | // slots (open, deleted, and empty) within the hash map. |
73 | | // * Returns `void` from the `erase(iterator)` overload. |
74 | | // |
75 | | // By default, `flat_hash_map` uses the `absl::Hash` hashing framework. |
76 | | // All fundamental and Abseil types that support the `absl::Hash` framework have |
77 | | // a compatible equality operator for comparing insertions into `flat_hash_map`. |
78 | | // If your type is not yet supported by the `absl::Hash` framework, see |
79 | | // absl/hash/hash.h for information on extending Abseil hashing to user-defined |
80 | | // types. |
81 | | // |
82 | | // Using `absl::flat_hash_map` at interface boundaries in dynamically loaded |
83 | | // libraries (e.g. .dll, .so) is unsupported due to way `absl::Hash` values may |
84 | | // be randomized across dynamically loaded libraries. |
85 | | // |
86 | | // To achieve heterogeneous lookup for custom types either `Hash` and `Eq` type |
87 | | // parameters can be used or `T` should have public inner types |
88 | | // `absl_container_hash` and (optionally) `absl_container_eq`. In either case, |
89 | | // `typename Hash::is_transparent` and `typename Eq::is_transparent` should be |
90 | | // well-formed. Both types are basically functors: |
91 | | // * `Hash` should support `size_t operator()(U val) const` that returns a hash |
92 | | // for the given `val`. |
93 | | // * `Eq` should support `bool operator()(U lhs, V rhs) const` that returns true |
94 | | // if `lhs` is equal to `rhs`. |
95 | | // |
96 | | // In most cases `T` needs only to provide the `absl_container_hash`. In this |
97 | | // case `std::equal_to<void>` will be used instead of `eq` part. |
98 | | // |
99 | | // NOTE: A `flat_hash_map` stores its value types directly inside its |
100 | | // implementation array to avoid memory indirection. Because a `flat_hash_map` |
101 | | // is designed to move data when rehashed, map values will not retain pointer |
102 | | // stability. If you require pointer stability, or if your values are large, |
103 | | // consider using `absl::flat_hash_map<Key, std::unique_ptr<Value>>` instead. |
104 | | // If your types are not moveable or you require pointer stability for keys, |
105 | | // consider `absl::node_hash_map`. |
106 | | // |
107 | | // Example: |
108 | | // |
109 | | // // Create a flat hash map of three strings (that map to strings) |
110 | | // absl::flat_hash_map<std::string, std::string> ducks = |
111 | | // {{"a", "huey"}, {"b", "dewey"}, {"c", "louie"}}; |
112 | | // |
113 | | // // Insert a new element into the flat hash map |
114 | | // ducks.insert({"d", "donald"}); |
115 | | // |
116 | | // // Force a rehash of the flat hash map |
117 | | // ducks.rehash(0); |
118 | | // |
119 | | // // Find the element with the key "b" |
120 | | // std::string search_key = "b"; |
121 | | // auto result = ducks.find(search_key); |
122 | | // if (result != ducks.end()) { |
123 | | // std::cout << "Result: " << result->second << std::endl; |
124 | | // } |
125 | | template <class K, class V, class Hash = DefaultHashContainerHash<K>, |
126 | | class Eq = DefaultHashContainerEq<K>, |
127 | | class Allocator = std::allocator<std::pair<const K, V>>> |
128 | | class ABSL_ATTRIBUTE_OWNER flat_hash_map |
129 | | : public absl::container_internal::raw_hash_map< |
130 | | absl::container_internal::FlatHashMapPolicy<K, V>, Hash, Eq, |
131 | | Allocator> { |
132 | | using Base = typename flat_hash_map::raw_hash_map; |
133 | | |
134 | | public: |
135 | | // Constructors and Assignment Operators |
136 | | // |
137 | | // A flat_hash_map supports the same overload set as `std::unordered_map` |
138 | | // for construction and assignment: |
139 | | // |
140 | | // * Default constructor |
141 | | // |
142 | | // // No allocation for the table's elements is made. |
143 | | // absl::flat_hash_map<int, std::string> map1; |
144 | | // |
145 | | // * Initializer List constructor |
146 | | // |
147 | | // absl::flat_hash_map<int, std::string> map2 = |
148 | | // {{1, "huey"}, {2, "dewey"}, {3, "louie"},}; |
149 | | // |
150 | | // * Copy constructor |
151 | | // |
152 | | // absl::flat_hash_map<int, std::string> map3(map2); |
153 | | // |
154 | | // * Copy assignment operator |
155 | | // |
156 | | // // Hash functor and Comparator are copied as well |
157 | | // absl::flat_hash_map<int, std::string> map4; |
158 | | // map4 = map3; |
159 | | // |
160 | | // * Move constructor |
161 | | // |
162 | | // // Move is guaranteed efficient |
163 | | // absl::flat_hash_map<int, std::string> map5(std::move(map4)); |
164 | | // |
165 | | // * Move assignment operator |
166 | | // |
167 | | // // May be efficient if allocators are compatible |
168 | | // absl::flat_hash_map<int, std::string> map6; |
169 | | // map6 = std::move(map5); |
170 | | // |
171 | | // * Range constructor |
172 | | // |
173 | | // std::vector<std::pair<int, std::string>> v = {{1, "a"}, {2, "b"}}; |
174 | | // absl::flat_hash_map<int, std::string> map7(v.begin(), v.end()); |
175 | 2 | flat_hash_map() {} |
176 | | using Base::Base; |
177 | | |
178 | | // flat_hash_map::begin() |
179 | | // |
180 | | // Returns an iterator to the beginning of the `flat_hash_map`. |
181 | | using Base::begin; |
182 | | |
183 | | // flat_hash_map::cbegin() |
184 | | // |
185 | | // Returns a const iterator to the beginning of the `flat_hash_map`. |
186 | | using Base::cbegin; |
187 | | |
188 | | // flat_hash_map::cend() |
189 | | // |
190 | | // Returns a const iterator to the end of the `flat_hash_map`. |
191 | | using Base::cend; |
192 | | |
193 | | // flat_hash_map::end() |
194 | | // |
195 | | // Returns an iterator to the end of the `flat_hash_map`. |
196 | | using Base::end; |
197 | | |
198 | | // flat_hash_map::capacity() |
199 | | // |
200 | | // Returns the number of element slots (assigned, deleted, and empty) |
201 | | // available within the `flat_hash_map`. |
202 | | // |
203 | | // NOTE: this member function is particular to `absl::flat_hash_map` and is |
204 | | // not provided in the `std::unordered_map` API. |
205 | | using Base::capacity; |
206 | | |
207 | | // flat_hash_map::empty() |
208 | | // |
209 | | // Returns whether or not the `flat_hash_map` is empty. |
210 | | using Base::empty; |
211 | | |
212 | | // flat_hash_map::max_size() |
213 | | // |
214 | | // Returns the largest theoretical possible number of elements within a |
215 | | // `flat_hash_map` under current memory constraints. This value can be thought |
216 | | // of the largest value of `std::distance(begin(), end())` for a |
217 | | // `flat_hash_map<K, V>`. |
218 | | using Base::max_size; |
219 | | |
220 | | // flat_hash_map::size() |
221 | | // |
222 | | // Returns the number of elements currently within the `flat_hash_map`. |
223 | | using Base::size; |
224 | | |
225 | | // flat_hash_map::clear() |
226 | | // |
227 | | // Removes all elements from the `flat_hash_map`. Invalidates any references, |
228 | | // pointers, or iterators referring to contained elements. |
229 | | // |
230 | | // NOTE: this operation may shrink the underlying buffer. To avoid shrinking |
231 | | // the underlying buffer call `erase(begin(), end())`. |
232 | | using Base::clear; |
233 | | |
234 | | // flat_hash_map::erase() |
235 | | // |
236 | | // Erases elements within the `flat_hash_map`. Erasing does not trigger a |
237 | | // rehash. Overloads are listed below. |
238 | | // |
239 | | // void erase(const_iterator pos): |
240 | | // |
241 | | // Erases the element at `position` of the `flat_hash_map`, returning |
242 | | // `void`. |
243 | | // |
244 | | // NOTE: returning `void` in this case is different than that of STL |
245 | | // containers in general and `std::unordered_map` in particular (which |
246 | | // return an iterator to the element following the erased element). If that |
247 | | // iterator is needed, simply post increment the iterator: |
248 | | // |
249 | | // map.erase(it++); |
250 | | // |
251 | | // iterator erase(const_iterator first, const_iterator last): |
252 | | // |
253 | | // Erases the elements in the open interval [`first`, `last`), returning an |
254 | | // iterator pointing to `last`. The special case of calling |
255 | | // `erase(begin(), end())` resets the reserved growth such that if |
256 | | // `reserve(N)` has previously been called and there has been no intervening |
257 | | // call to `clear()`, then after calling `erase(begin(), end())`, it is safe |
258 | | // to assume that inserting N elements will not cause a rehash. |
259 | | // |
260 | | // size_type erase(const key_type& key): |
261 | | // |
262 | | // Erases the element with the matching key, if it exists, returning the |
263 | | // number of elements erased (0 or 1). |
264 | | using Base::erase; |
265 | | |
266 | | // flat_hash_map::insert() |
267 | | // |
268 | | // Inserts an element of the specified value into the `flat_hash_map`, |
269 | | // returning an iterator pointing to the newly inserted element, provided that |
270 | | // an element with the given key does not already exist. If rehashing occurs |
271 | | // due to the insertion, all iterators are invalidated. Overloads are listed |
272 | | // below. |
273 | | // |
274 | | // std::pair<iterator,bool> insert(const init_type& value): |
275 | | // |
276 | | // Inserts a value into the `flat_hash_map`. Returns a pair consisting of an |
277 | | // iterator to the inserted element (or to the element that prevented the |
278 | | // insertion) and a bool denoting whether the insertion took place. |
279 | | // |
280 | | // std::pair<iterator,bool> insert(T&& value): |
281 | | // std::pair<iterator,bool> insert(init_type&& value): |
282 | | // |
283 | | // Inserts a moveable value into the `flat_hash_map`. Returns a pair |
284 | | // consisting of an iterator to the inserted element (or to the element that |
285 | | // prevented the insertion) and a bool denoting whether the insertion took |
286 | | // place. |
287 | | // |
288 | | // iterator insert(const_iterator hint, const init_type& value): |
289 | | // iterator insert(const_iterator hint, T&& value): |
290 | | // iterator insert(const_iterator hint, init_type&& value); |
291 | | // |
292 | | // Inserts a value, using the position of `hint` as a non-binding suggestion |
293 | | // for where to begin the insertion search. Returns an iterator to the |
294 | | // inserted element, or to the existing element that prevented the |
295 | | // insertion. |
296 | | // |
297 | | // void insert(InputIterator first, InputIterator last): |
298 | | // |
299 | | // Inserts a range of values [`first`, `last`). |
300 | | // |
301 | | // NOTE: Although the STL does not specify which element may be inserted if |
302 | | // multiple keys compare equivalently, for `flat_hash_map` we guarantee the |
303 | | // first match is inserted. |
304 | | // |
305 | | // void insert(std::initializer_list<init_type> ilist): |
306 | | // |
307 | | // Inserts the elements within the initializer list `ilist`. |
308 | | // |
309 | | // NOTE: Although the STL does not specify which element may be inserted if |
310 | | // multiple keys compare equivalently within the initializer list, for |
311 | | // `flat_hash_map` we guarantee the first match is inserted. |
312 | | using Base::insert; |
313 | | |
314 | | // flat_hash_map::insert_or_assign() |
315 | | // |
316 | | // Inserts an element of the specified value into the `flat_hash_map` provided |
317 | | // that a value with the given key does not already exist, or replaces it with |
318 | | // the element value if a key for that value already exists, returning an |
319 | | // iterator pointing to the newly inserted element. If rehashing occurs due |
320 | | // to the insertion, all existing iterators are invalidated. Overloads are |
321 | | // listed below. |
322 | | // |
323 | | // pair<iterator, bool> insert_or_assign(const init_type& k, T&& obj): |
324 | | // pair<iterator, bool> insert_or_assign(init_type&& k, T&& obj): |
325 | | // |
326 | | // Inserts/Assigns (or moves) the element of the specified key into the |
327 | | // `flat_hash_map`. |
328 | | // |
329 | | // iterator insert_or_assign(const_iterator hint, |
330 | | // const init_type& k, T&& obj): |
331 | | // iterator insert_or_assign(const_iterator hint, init_type&& k, T&& obj): |
332 | | // |
333 | | // Inserts/Assigns (or moves) the element of the specified key into the |
334 | | // `flat_hash_map` using the position of `hint` as a non-binding suggestion |
335 | | // for where to begin the insertion search. |
336 | | using Base::insert_or_assign; |
337 | | |
338 | | // flat_hash_map::emplace() |
339 | | // |
340 | | // Inserts an element of the specified value by constructing it in-place |
341 | | // within the `flat_hash_map`, provided that no element with the given key |
342 | | // already exists. |
343 | | // |
344 | | // The element may be constructed even if there already is an element with the |
345 | | // key in the container, in which case the newly constructed element will be |
346 | | // destroyed immediately. Prefer `try_emplace()` unless your key is not |
347 | | // copyable or moveable. |
348 | | // |
349 | | // If rehashing occurs due to the insertion, all iterators are invalidated. |
350 | | using Base::emplace; |
351 | | |
352 | | // flat_hash_map::emplace_hint() |
353 | | // |
354 | | // Inserts an element of the specified value by constructing it in-place |
355 | | // within the `flat_hash_map`, using the position of `hint` as a non-binding |
356 | | // suggestion for where to begin the insertion search, and only inserts |
357 | | // provided that no element with the given key already exists. |
358 | | // |
359 | | // The element may be constructed even if there already is an element with the |
360 | | // key in the container, in which case the newly constructed element will be |
361 | | // destroyed immediately. Prefer `try_emplace()` unless your key is not |
362 | | // copyable or moveable. |
363 | | // |
364 | | // If rehashing occurs due to the insertion, all iterators are invalidated. |
365 | | using Base::emplace_hint; |
366 | | |
367 | | // flat_hash_map::try_emplace() |
368 | | // |
369 | | // Inserts an element of the specified value by constructing it in-place |
370 | | // within the `flat_hash_map`, provided that no element with the given key |
371 | | // already exists. Unlike `emplace()`, if an element with the given key |
372 | | // already exists, we guarantee that no element is constructed. |
373 | | // |
374 | | // If rehashing occurs due to the insertion, all iterators are invalidated. |
375 | | // Overloads are listed below. |
376 | | // |
377 | | // pair<iterator, bool> try_emplace(const key_type& k, Args&&... args): |
378 | | // pair<iterator, bool> try_emplace(key_type&& k, Args&&... args): |
379 | | // |
380 | | // Inserts (via copy or move) the element of the specified key into the |
381 | | // `flat_hash_map`. |
382 | | // |
383 | | // iterator try_emplace(const_iterator hint, |
384 | | // const key_type& k, Args&&... args): |
385 | | // iterator try_emplace(const_iterator hint, key_type&& k, Args&&... args): |
386 | | // |
387 | | // Inserts (via copy or move) the element of the specified key into the |
388 | | // `flat_hash_map` using the position of `hint` as a non-binding suggestion |
389 | | // for where to begin the insertion search. |
390 | | // |
391 | | // All `try_emplace()` overloads make the same guarantees regarding rvalue |
392 | | // arguments as `std::unordered_map::try_emplace()`, namely that these |
393 | | // functions will not move from rvalue arguments if insertions do not happen. |
394 | | using Base::try_emplace; |
395 | | |
396 | | // flat_hash_map::extract() |
397 | | // |
398 | | // Extracts the indicated element, erasing it in the process, and returns it |
399 | | // as a C++17-compatible node handle. Overloads are listed below. |
400 | | // |
401 | | // node_type extract(const_iterator position): |
402 | | // |
403 | | // Extracts the key,value pair of the element at the indicated position and |
404 | | // returns a node handle owning that extracted data. |
405 | | // |
406 | | // node_type extract(const key_type& x): |
407 | | // |
408 | | // Extracts the key,value pair of the element with a key matching the passed |
409 | | // key value and returns a node handle owning that extracted data. If the |
410 | | // `flat_hash_map` does not contain an element with a matching key, this |
411 | | // function returns an empty node handle. |
412 | | // |
413 | | // NOTE: when compiled in an earlier version of C++ than C++17, |
414 | | // `node_type::key()` returns a const reference to the key instead of a |
415 | | // mutable reference. We cannot safely return a mutable reference without |
416 | | // std::launder (which is not available before C++17). |
417 | | using Base::extract; |
418 | | |
419 | | // flat_hash_map::merge() |
420 | | // |
421 | | // Extracts elements from a given `source` flat hash map into this |
422 | | // `flat_hash_map`. If the destination `flat_hash_map` already contains an |
423 | | // element with an equivalent key, that element is not extracted. |
424 | | using Base::merge; |
425 | | |
426 | | // flat_hash_map::swap(flat_hash_map& other) |
427 | | // |
428 | | // Exchanges the contents of this `flat_hash_map` with those of the `other` |
429 | | // flat hash map. |
430 | | // |
431 | | // All iterators and references on the `flat_hash_map` remain valid, excepting |
432 | | // for the past-the-end iterator, which is invalidated. |
433 | | // |
434 | | // `swap()` requires that the flat hash map's hashing and key equivalence |
435 | | // functions be Swappable, and are exchanged using unqualified calls to |
436 | | // non-member `swap()`. If the map's allocator has |
437 | | // `std::allocator_traits<allocator_type>::propagate_on_container_swap::value` |
438 | | // set to `true`, the allocators are also exchanged using an unqualified call |
439 | | // to non-member `swap()`; otherwise, the allocators are not swapped. |
440 | | using Base::swap; |
441 | | |
442 | | // flat_hash_map::rehash(count) |
443 | | // |
444 | | // Rehashes the `flat_hash_map`, setting the number of slots to be at least |
445 | | // the passed value. If the new number of slots increases the load factor more |
446 | | // than the current maximum load factor |
447 | | // (`count` < `size()` / `max_load_factor()`), then the new number of slots |
448 | | // will be at least `size()` / `max_load_factor()`. |
449 | | // |
450 | | // To force a rehash, pass rehash(0). |
451 | | // |
452 | | // NOTE: unlike behavior in `std::unordered_map`, references are also |
453 | | // invalidated upon a `rehash()`. |
454 | | using Base::rehash; |
455 | | |
456 | | // flat_hash_map::reserve(count) |
457 | | // |
458 | | // Sets the number of slots in the `flat_hash_map` to the number needed to |
459 | | // accommodate at least `count` total elements without exceeding the current |
460 | | // maximum load factor, and may rehash the container if needed. |
461 | | using Base::reserve; |
462 | | |
463 | | // flat_hash_map::at() |
464 | | // |
465 | | // Returns a reference to the mapped value of the element with key equivalent |
466 | | // to the passed key. |
467 | | using Base::at; |
468 | | |
469 | | // flat_hash_map::contains() |
470 | | // |
471 | | // Determines whether an element with a key comparing equal to the given `key` |
472 | | // exists within the `flat_hash_map`, returning `true` if so or `false` |
473 | | // otherwise. |
474 | | using Base::contains; |
475 | | |
476 | | // flat_hash_map::count(const Key& key) const |
477 | | // |
478 | | // Returns the number of elements with a key comparing equal to the given |
479 | | // `key` within the `flat_hash_map`. note that this function will return |
480 | | // either `1` or `0` since duplicate keys are not allowed within a |
481 | | // `flat_hash_map`. |
482 | | using Base::count; |
483 | | |
484 | | // flat_hash_map::equal_range() |
485 | | // |
486 | | // Returns a closed range [first, last], defined by a `std::pair` of two |
487 | | // iterators, containing all elements with the passed key in the |
488 | | // `flat_hash_map`. |
489 | | using Base::equal_range; |
490 | | |
491 | | // flat_hash_map::find() |
492 | | // |
493 | | // Finds an element with the passed `key` within the `flat_hash_map`. |
494 | | using Base::find; |
495 | | |
496 | | // flat_hash_map::operator[]() |
497 | | // |
498 | | // Returns a reference to the value mapped to the passed key within the |
499 | | // `flat_hash_map`, performing an `insert()` if the key does not already |
500 | | // exist. |
501 | | // |
502 | | // If an insertion occurs and results in a rehashing of the container, all |
503 | | // iterators are invalidated. Otherwise iterators are not affected and |
504 | | // references are not invalidated. Overloads are listed below. |
505 | | // |
506 | | // T& operator[](const Key& key): |
507 | | // |
508 | | // Inserts an init_type object constructed in-place if the element with the |
509 | | // given key does not exist. |
510 | | // |
511 | | // T& operator[](Key&& key): |
512 | | // |
513 | | // Inserts an init_type object constructed in-place provided that an element |
514 | | // with the given key does not exist. |
515 | | using Base::operator[]; |
516 | | |
517 | | // flat_hash_map::bucket_count() |
518 | | // |
519 | | // Returns the number of "buckets" within the `flat_hash_map`. Note that |
520 | | // because a flat hash map contains all elements within its internal storage, |
521 | | // this value simply equals the current capacity of the `flat_hash_map`. |
522 | | using Base::bucket_count; |
523 | | |
524 | | // flat_hash_map::load_factor() |
525 | | // |
526 | | // Returns the current load factor of the `flat_hash_map` (the average number |
527 | | // of slots occupied with a value within the hash map). |
528 | | using Base::load_factor; |
529 | | |
530 | | // flat_hash_map::max_load_factor() |
531 | | // |
532 | | // Manages the maximum load factor of the `flat_hash_map`. Overloads are |
533 | | // listed below. |
534 | | // |
535 | | // float flat_hash_map::max_load_factor() |
536 | | // |
537 | | // Returns the current maximum load factor of the `flat_hash_map`. |
538 | | // |
539 | | // void flat_hash_map::max_load_factor(float ml) |
540 | | // |
541 | | // Sets the maximum load factor of the `flat_hash_map` to the passed value. |
542 | | // |
543 | | // NOTE: This overload is provided only for API compatibility with the STL; |
544 | | // `flat_hash_map` will ignore any set load factor and manage its rehashing |
545 | | // internally as an implementation detail. |
546 | | using Base::max_load_factor; |
547 | | |
548 | | // flat_hash_map::get_allocator() |
549 | | // |
550 | | // Returns the allocator function associated with this `flat_hash_map`. |
551 | | using Base::get_allocator; |
552 | | |
553 | | // flat_hash_map::hash_function() |
554 | | // |
555 | | // Returns the hashing function used to hash the keys within this |
556 | | // `flat_hash_map`. |
557 | | using Base::hash_function; |
558 | | |
559 | | // flat_hash_map::key_eq() |
560 | | // |
561 | | // Returns the function used for comparing keys equality. |
562 | | using Base::key_eq; |
563 | | }; |
564 | | |
565 | | // erase_if(flat_hash_map<>, Pred) |
566 | | // |
567 | | // Erases all elements that satisfy the predicate `pred` from the container `c`. |
568 | | // Returns the number of erased elements. |
569 | | template <typename K, typename V, typename H, typename E, typename A, |
570 | | typename Predicate> |
571 | | typename flat_hash_map<K, V, H, E, A>::size_type erase_if( |
572 | | flat_hash_map<K, V, H, E, A>& c, Predicate pred) { |
573 | | return container_internal::EraseIf(pred, &c); |
574 | | } |
575 | | |
576 | | // swap(flat_hash_map<>, flat_hash_map<>) |
577 | | // |
578 | | // Swaps the contents of two `flat_hash_map` containers. |
579 | | // |
580 | | // NOTE: we need to define this function template in order for |
581 | | // `flat_hash_set::swap` to be called instead of `std::swap`. Even though we |
582 | | // have `swap(raw_hash_set&, raw_hash_set&)` defined, that function requires a |
583 | | // derived-to-base conversion, whereas `std::swap` is a function template so |
584 | | // `std::swap` will be preferred by compiler. |
585 | | template <typename K, typename V, typename H, typename E, typename A> |
586 | | void swap(flat_hash_map<K, V, H, E, A>& x, |
587 | | flat_hash_map<K, V, H, E, A>& y) noexcept(noexcept(x.swap(y))) { |
588 | | x.swap(y); |
589 | | } |
590 | | |
591 | | namespace container_internal { |
592 | | |
593 | | // c_for_each_fast(flat_hash_map<>, Function) |
594 | | // |
595 | | // Container-based version of the <algorithm> `std::for_each()` function to |
596 | | // apply a function to a container's elements. |
597 | | // There is no guarantees on the order of the function calls. |
598 | | // Erasure and/or insertion of elements in the function is not allowed. |
599 | | template <typename K, typename V, typename H, typename E, typename A, |
600 | | typename Function> |
601 | | decay_t<Function> c_for_each_fast(const flat_hash_map<K, V, H, E, A>& c, |
602 | | Function&& f) { |
603 | | container_internal::ForEach(f, &c); |
604 | | return f; |
605 | | } |
606 | | template <typename K, typename V, typename H, typename E, typename A, |
607 | | typename Function> |
608 | | decay_t<Function> c_for_each_fast(flat_hash_map<K, V, H, E, A>& c, |
609 | | Function&& f) { |
610 | | container_internal::ForEach(f, &c); |
611 | | return f; |
612 | | } |
613 | | template <typename K, typename V, typename H, typename E, typename A, |
614 | | typename Function> |
615 | | decay_t<Function> c_for_each_fast(flat_hash_map<K, V, H, E, A>&& c, |
616 | | Function&& f) { |
617 | | container_internal::ForEach(f, &c); |
618 | | return f; |
619 | | } |
620 | | |
621 | | } // namespace container_internal |
622 | | |
623 | | namespace container_internal { |
624 | | |
625 | | template <class K, class V> |
626 | | struct FlatHashMapPolicy { |
627 | | using slot_policy = container_internal::map_slot_policy<K, V>; |
628 | | using slot_type = typename slot_policy::slot_type; |
629 | | using key_type = K; |
630 | | using mapped_type = V; |
631 | | using init_type = std::pair</*non const*/ key_type, mapped_type>; |
632 | | |
633 | | template <class Allocator, class... Args> |
634 | 16 | static void construct(Allocator* alloc, slot_type* slot, Args&&... args) { |
635 | 16 | slot_policy::construct(alloc, slot, std::forward<Args>(args)...); |
636 | 16 | } void absl::container_internal::FlatHashMapPolicy<std::__1::basic_string_view<char, std::__1::char_traits<char> >, absl::CommandLineFlag*>::construct<std::__1::allocator<std::__1::pair<std::__1::basic_string_view<char, std::__1::char_traits<char> > const, absl::CommandLineFlag*> >, std::__1::piecewise_construct_t const&, std::__1::tuple<std::__1::basic_string_view<char, std::__1::char_traits<char> > const&&>, std::__1::tuple<absl::CommandLineFlag*&&> >(std::__1::allocator<std::__1::pair<std::__1::basic_string_view<char, std::__1::char_traits<char> > const, absl::CommandLineFlag*> >*, absl::container_internal::map_slot_type<std::__1::basic_string_view<char, std::__1::char_traits<char> >, absl::CommandLineFlag*>*, std::__1::piecewise_construct_t const&, std::__1::tuple<std::__1::basic_string_view<char, std::__1::char_traits<char> > const&&>&&, std::__1::tuple<absl::CommandLineFlag*&&>&&) Line | Count | Source | 634 | 16 | static void construct(Allocator* alloc, slot_type* slot, Args&&... args) { | 635 | 16 | slot_policy::construct(alloc, slot, std::forward<Args>(args)...); | 636 | 16 | } |
Unexecuted instantiation: void absl::container_internal::FlatHashMapPolicy<std::__1::basic_string_view<char, std::__1::char_traits<char> >, absl::CommandLineFlag*>::construct<std::__1::allocator<std::__1::pair<std::__1::basic_string_view<char, std::__1::char_traits<char> > const, absl::CommandLineFlag*> >, std::__1::piecewise_construct_t const&, std::__1::tuple<std::__1::basic_string_view<char, std::__1::char_traits<char> >&&>, std::__1::tuple<absl::CommandLineFlag*&&> >(std::__1::allocator<std::__1::pair<std::__1::basic_string_view<char, std::__1::char_traits<char> > const, absl::CommandLineFlag*> >*, absl::container_internal::map_slot_type<std::__1::basic_string_view<char, std::__1::char_traits<char> >, absl::CommandLineFlag*>*, std::__1::piecewise_construct_t const&, std::__1::tuple<std::__1::basic_string_view<char, std::__1::char_traits<char> >&&>&&, std::__1::tuple<absl::CommandLineFlag*&&>&&) |
637 | | |
638 | | // Returns std::true_type in case destroy is trivial. |
639 | | template <class Allocator> |
640 | 0 | static auto destroy(Allocator* alloc, slot_type* slot) { |
641 | 0 | return slot_policy::destroy(alloc, slot); |
642 | 0 | } |
643 | | |
644 | | template <class Allocator> |
645 | | static auto transfer(Allocator* alloc, slot_type* new_slot, |
646 | 0 | slot_type* old_slot) { |
647 | 0 | return slot_policy::transfer(alloc, new_slot, old_slot); |
648 | 0 | } Unexecuted instantiation: auto absl::container_internal::FlatHashMapPolicy<std::__1::basic_string_view<char, std::__1::char_traits<char> >, absl::CommandLineFlag*>::transfer<std::__1::allocator<std::__1::pair<std::__1::basic_string_view<char, std::__1::char_traits<char> > const, absl::CommandLineFlag*> > >(std::__1::allocator<std::__1::pair<std::__1::basic_string_view<char, std::__1::char_traits<char> > const, absl::CommandLineFlag*> >*, absl::container_internal::map_slot_type<std::__1::basic_string_view<char, std::__1::char_traits<char> >, absl::CommandLineFlag*>*, absl::container_internal::map_slot_type<std::__1::basic_string_view<char, std::__1::char_traits<char> >, absl::CommandLineFlag*>*) Unexecuted instantiation: auto absl::container_internal::FlatHashMapPolicy<std::__1::basic_string_view<char, std::__1::char_traits<char> >, absl::CommandLineFlag*>::transfer<std::__1::allocator<char> >(std::__1::allocator<char>*, absl::container_internal::map_slot_type<std::__1::basic_string_view<char, std::__1::char_traits<char> >, absl::CommandLineFlag*>*, absl::container_internal::map_slot_type<std::__1::basic_string_view<char, std::__1::char_traits<char> >, absl::CommandLineFlag*>*) |
649 | | |
650 | | template <class F, class... Args> |
651 | | static decltype(absl::container_internal::DecomposePair( |
652 | | std::declval<F>(), std::declval<Args>()...)) |
653 | 51 | apply(F&& f, Args&&... args) { |
654 | 51 | return absl::container_internal::DecomposePair(std::forward<F>(f), |
655 | 51 | std::forward<Args>(args)...); |
656 | 51 | } _ZN4absl18container_internal17FlatHashMapPolicyINSt3__117basic_string_viewIcNS2_11char_traitsIcEEEEPNS_15CommandLineFlagEE5applyINS0_12raw_hash_setIS9_NS0_10StringHashENS0_8StringEqENS2_9allocatorINS2_4pairIKS6_S8_EEEEE12EqualElementIS6_EEJRSH_EEEDTclsr4absl18container_internalE13DecomposePairclsr3stdE7declvalIT_EEspclsr3stdE7declvalIT0_EEEEOSN_DpOSO_ Line | Count | Source | 653 | 19 | apply(F&& f, Args&&... args) { | 654 | 19 | return absl::container_internal::DecomposePair(std::forward<F>(f), | 655 | 19 | std::forward<Args>(args)...); | 656 | 19 | } |
_ZN4absl18container_internal17FlatHashMapPolicyINSt3__117basic_string_viewIcNS2_11char_traitsIcEEEEPNS_15CommandLineFlagEE5applyINS0_12raw_hash_setIS9_NS0_10StringHashENS0_8StringEqENS2_9allocatorINS2_4pairIKS6_S8_EEEEE19EmplaceDecomposableEJSH_EEEDTclsr4absl18container_internalE13DecomposePairclsr3stdE7declvalIT_EEspclsr3stdE7declvalIT0_EEEEOSL_DpOSM_ Line | Count | Source | 653 | 16 | apply(F&& f, Args&&... args) { | 654 | 16 | return absl::container_internal::DecomposePair(std::forward<F>(f), | 655 | 16 | std::forward<Args>(args)...); | 656 | 16 | } |
Unexecuted instantiation: _ZN4absl18container_internal17FlatHashMapPolicyINSt3__117basic_string_viewIcNS2_11char_traitsIcEEEEPNS_15CommandLineFlagEE5applyINS0_12raw_hash_setIS9_NS0_10StringHashENS0_8StringEqENS2_9allocatorINS2_4pairIKS6_S8_EEEEE11HashElementEJRSH_EEEDTclsr4absl18container_internalE13DecomposePairclsr3stdE7declvalIT_EEspclsr3stdE7declvalIT0_EEEEOSM_DpOSN_ _ZN4absl18container_internal17FlatHashMapPolicyINSt3__117basic_string_viewIcNS2_11char_traitsIcEEEEPNS_15CommandLineFlagEE5applyINS0_12raw_hash_setIS9_NS0_10StringHashENS0_8StringEqENS2_9allocatorINS2_4pairIKS6_S8_EEEEE11FindElementEJRSH_EEEDTclsr4absl18container_internalE13DecomposePairclsr3stdE7declvalIT_EEspclsr3stdE7declvalIT0_EEEEOSM_DpOSN_ Line | Count | Source | 653 | 16 | apply(F&& f, Args&&... args) { | 654 | 16 | return absl::container_internal::DecomposePair(std::forward<F>(f), | 655 | 16 | std::forward<Args>(args)...); | 656 | 16 | } |
Unexecuted instantiation: _ZN4absl18container_internal17FlatHashMapPolicyINSt3__117basic_string_viewIcNS2_11char_traitsIcEEEEPNS_15CommandLineFlagEE5applyINS0_12raw_hash_setIS9_NS0_10StringHashENS0_8StringEqENS2_9allocatorINS2_4pairIKS6_S8_EEEEE19EmplaceDecomposableEJNSF_IS6_S8_EEEEEDTclsr4absl18container_internalE13DecomposePairclsr3stdE7declvalIT_EEspclsr3stdE7declvalIT0_EEEEOSM_DpOSN_ Unexecuted instantiation: _ZN4absl18container_internal17FlatHashMapPolicyINSt3__117basic_string_viewIcNS2_11char_traitsIcEEEEPNS_15CommandLineFlagEE5applyINS0_12raw_hash_setIS9_NS0_10StringHashENS0_8StringEqENS2_9allocatorINS2_4pairIKS6_S8_EEEEE12EqualElementIS6_EEJRKSH_EEEDTclsr4absl18container_internalE13DecomposePairclsr3stdE7declvalIT_EEspclsr3stdE7declvalIT0_EEEEOSO_DpOSP_ Unexecuted instantiation: _ZN4absl18container_internal17FlatHashMapPolicyINSt3__117basic_string_viewIcNS2_11char_traitsIcEEEEPNS_15CommandLineFlagEE5applyINS0_12raw_hash_setIS9_NS0_10StringHashENS0_8StringEqENS2_9allocatorINS2_4pairIKS6_S8_EEEEE11HashElementEJRKSH_EEEDTclsr4absl18container_internalE13DecomposePairclsr3stdE7declvalIT_EEspclsr3stdE7declvalIT0_EEEEOSN_DpOSO_ Unexecuted instantiation: _ZN4absl18container_internal17FlatHashMapPolicyINSt3__117basic_string_viewIcNS2_11char_traitsIcEEEEPNS_15CommandLineFlagEE5applyINS0_18hash_policy_traitsIS9_vE11HashElementINS0_10StringHashEEEJRNS2_4pairIKS6_S8_EEEEEDTclsr4absl18container_internalE13DecomposePairclsr3stdE7declvalIT_EEspclsr3stdE7declvalIT0_EEEEOSK_DpOSL_ |
657 | | |
658 | | template <class Hash> |
659 | 0 | static constexpr HashSlotFn get_hash_slot_fn() { |
660 | 0 | return memory_internal::IsLayoutCompatible<K, V>::value |
661 | 0 | ? &TypeErasedApplyToSlotFn<Hash, K> |
662 | 0 | : nullptr; |
663 | 0 | } |
664 | | |
665 | | static size_t space_used(const slot_type*) { return 0; } |
666 | | |
667 | 35 | static std::pair<const K, V>& element(slot_type* slot) { return slot->value; } |
668 | | |
669 | | static V& value(std::pair<const K, V>* kv) { return kv->second; } |
670 | | static const V& value(const std::pair<const K, V>* kv) { return kv->second; } |
671 | | }; |
672 | | |
673 | | } // namespace container_internal |
674 | | |
675 | | namespace container_algorithm_internal { |
676 | | |
677 | | // Specialization of trait in absl/algorithm/container.h |
678 | | template <class Key, class T, class Hash, class KeyEqual, class Allocator> |
679 | | struct IsUnorderedContainer< |
680 | | absl::flat_hash_map<Key, T, Hash, KeyEqual, Allocator>> : std::true_type {}; |
681 | | |
682 | | } // namespace container_algorithm_internal |
683 | | |
684 | | ABSL_NAMESPACE_END |
685 | | } // namespace absl |
686 | | |
687 | | #endif // ABSL_CONTAINER_FLAT_HASH_MAP_H_ |