| // Copyright 2018 The Abseil Authors. |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // https://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| // |
| // ----------------------------------------------------------------------------- |
| // File: btree_map.h |
| // ----------------------------------------------------------------------------- |
| // |
| // This header file defines B-tree maps: sorted associative containers mapping |
| // keys to values. |
| // |
| // * `absl::btree_map<>` |
| // * `absl::btree_multimap<>` |
| // |
| // These B-tree types are similar to the corresponding types in the STL |
| // (`std::map` and `std::multimap`) and generally conform to the STL interfaces |
| // of those types. However, because they are implemented using B-trees, they |
| // are more efficient in most situations. |
| // |
| // Unlike `std::map` and `std::multimap`, which are commonly implemented using |
| // red-black tree nodes, B-tree maps use more generic B-tree nodes able to hold |
| // multiple values per node. Holding multiple values per node often makes |
| // B-tree maps perform better than their `std::map` counterparts, because |
| // multiple entries can be checked within the same cache hit. |
| // |
| // However, these types should not be considered drop-in replacements for |
| // `std::map` and `std::multimap` as there are some API differences, which are |
| // noted in this header file. The most consequential differences with respect to |
| // migrating to b-tree from the STL types are listed in the next paragraph. |
| // Other API differences are minor. |
| // |
| // Importantly, insertions and deletions may invalidate outstanding iterators, |
| // pointers, and references to elements. Such invalidations are typically only |
| // an issue if insertion and deletion operations are interleaved with the use of |
| // more than one iterator, pointer, or reference simultaneously. For this |
| // reason, `insert()` and `erase()` return a valid iterator at the current |
| // position. Another important difference is that key-types must be |
| // copy-constructible. |
| |
| #ifndef ABSL_CONTAINER_BTREE_MAP_H_ |
| #define ABSL_CONTAINER_BTREE_MAP_H_ |
| |
| #include "absl/container/internal/btree.h" // IWYU pragma: export |
| #include "absl/container/internal/btree_container.h" // IWYU pragma: export |
| |
| namespace absl { |
| ABSL_NAMESPACE_BEGIN |
| |
| namespace container_internal { |
| |
| template <typename Key, typename Data, typename Compare, typename Alloc, |
| int TargetNodeSize, bool IsMulti> |
| struct map_params; |
| |
| } // namespace container_internal |
| |
| // absl::btree_map<> |
| // |
| // An `absl::btree_map<K, V>` is an ordered associative container of |
| // unique keys and associated values designed to be a more efficient replacement |
| // for `std::map` (in most cases). |
| // |
| // Keys are sorted using an (optional) comparison function, which defaults to |
| // `std::less<K>`. |
| // |
| // An `absl::btree_map<K, V>` uses a default allocator of |
| // `std::allocator<std::pair<const K, V>>` to allocate (and deallocate) |
| // nodes, and construct and destruct values within those nodes. You may |
| // instead specify a custom allocator `A` (which in turn requires specifying a |
| // custom comparator `C`) as in `absl::btree_map<K, V, C, A>`. |
| // |
| template <typename Key, typename Value, typename Compare = std::less<Key>, |
| typename Alloc = std::allocator<std::pair<const Key, Value>>> |
| class btree_map |
| : public container_internal::btree_map_container< |
| container_internal::btree<container_internal::map_params< |
| Key, Value, Compare, Alloc, /*TargetNodeSize=*/256, |
| /*IsMulti=*/false>>> { |
| using Base = typename btree_map::btree_map_container; |
| |
| public: |
| // Constructors and Assignment Operators |
| // |
| // A `btree_map` supports the same overload set as `std::map` |
| // for construction and assignment: |
| // |
| // * Default constructor |
| // |
| // absl::btree_map<int, std::string> map1; |
| // |
| // * Initializer List constructor |
| // |
| // absl::btree_map<int, std::string> map2 = |
| // {{1, "huey"}, {2, "dewey"}, {3, "louie"},}; |
| // |
| // * Copy constructor |
| // |
| // absl::btree_map<int, std::string> map3(map2); |
| // |
| // * Copy assignment operator |
| // |
| // absl::btree_map<int, std::string> map4; |
| // map4 = map3; |
| // |
| // * Move constructor |
| // |
| // // Move is guaranteed efficient |
| // absl::btree_map<int, std::string> map5(std::move(map4)); |
| // |
| // * Move assignment operator |
| // |
| // // May be efficient if allocators are compatible |
| // absl::btree_map<int, std::string> map6; |
| // map6 = std::move(map5); |
| // |
| // * Range constructor |
| // |
| // std::vector<std::pair<int, std::string>> v = {{1, "a"}, {2, "b"}}; |
| // absl::btree_map<int, std::string> map7(v.begin(), v.end()); |
| btree_map() {} |
| using Base::Base; |
| |
| // btree_map::begin() |
| // |
| // Returns an iterator to the beginning of the `btree_map`. |
| using Base::begin; |
| |
| // btree_map::cbegin() |
| // |
| // Returns a const iterator to the beginning of the `btree_map`. |
| using Base::cbegin; |
| |
| // btree_map::end() |
| // |
| // Returns an iterator to the end of the `btree_map`. |
| using Base::end; |
| |
| // btree_map::cend() |
| // |
| // Returns a const iterator to the end of the `btree_map`. |
| using Base::cend; |
| |
| // btree_map::empty() |
| // |
| // Returns whether or not the `btree_map` is empty. |
| using Base::empty; |
| |
| // btree_map::max_size() |
| // |
| // Returns the largest theoretical possible number of elements within a |
| // `btree_map` under current memory constraints. This value can be thought |
| // of as the largest value of `std::distance(begin(), end())` for a |
| // `btree_map<Key, T>`. |
| using Base::max_size; |
| |
| // btree_map::size() |
| // |
| // Returns the number of elements currently within the `btree_map`. |
| using Base::size; |
| |
| // btree_map::clear() |
| // |
| // Removes all elements from the `btree_map`. Invalidates any references, |
| // pointers, or iterators referring to contained elements. |
| using Base::clear; |
| |
| // btree_map::erase() |
| // |
| // Erases elements within the `btree_map`. If an erase occurs, any references, |
| // pointers, or iterators are invalidated. |
| // Overloads are listed below. |
| // |
| // iterator erase(iterator position): |
| // iterator erase(const_iterator position): |
| // |
| // Erases the element at `position` of the `btree_map`, returning |
| // the iterator pointing to the element after the one that was erased |
| // (or end() if none exists). |
| // |
| // iterator erase(const_iterator first, const_iterator last): |
| // |
| // Erases the elements in the open interval [`first`, `last`), returning |
| // the iterator pointing to the element after the interval that was erased |
| // (or end() if none exists). |
| // |
| // template <typename K> size_type erase(const K& key): |
| // |
| // Erases the element with the matching key, if it exists, returning the |
| // number of elements erased (0 or 1). |
| using Base::erase; |
| |
| // btree_map::insert() |
| // |
| // Inserts an element of the specified value into the `btree_map`, |
| // returning an iterator pointing to the newly inserted element, provided that |
| // an element with the given key does not already exist. If an insertion |
| // occurs, any references, pointers, or iterators are invalidated. |
| // Overloads are listed below. |
| // |
| // std::pair<iterator,bool> insert(const value_type& value): |
| // |
| // Inserts a value into the `btree_map`. Returns a pair consisting of an |
| // iterator to the inserted element (or to the element that prevented the |
| // insertion) and a bool denoting whether the insertion took place. |
| // |
| // std::pair<iterator,bool> insert(value_type&& value): |
| // |
| // Inserts a moveable value into the `btree_map`. Returns a pair |
| // consisting of an iterator to the inserted element (or to the element that |
| // prevented the insertion) and a bool denoting whether the insertion took |
| // place. |
| // |
| // iterator insert(const_iterator hint, const value_type& value): |
| // iterator insert(const_iterator hint, value_type&& value): |
| // |
| // Inserts a value, using the position of `hint` as a non-binding suggestion |
| // for where to begin the insertion search. Returns an iterator to the |
| // inserted element, or to the existing element that prevented the |
| // insertion. |
| // |
| // void insert(InputIterator first, InputIterator last): |
| // |
| // Inserts a range of values [`first`, `last`). |
| // |
| // void insert(std::initializer_list<init_type> ilist): |
| // |
| // Inserts the elements within the initializer list `ilist`. |
| using Base::insert; |
| |
| // btree_map::insert_or_assign() |
| // |
| // Inserts an element of the specified value into the `btree_map` provided |
| // that a value with the given key does not already exist, or replaces the |
| // corresponding mapped type with the forwarded `obj` argument if a key for |
| // that value already exists, returning an iterator pointing to the newly |
| // inserted element. Overloads are listed below. |
| // |
| // pair<iterator, bool> insert_or_assign(const key_type& k, M&& obj): |
| // pair<iterator, bool> insert_or_assign(key_type&& k, M&& obj): |
| // |
| // Inserts/Assigns (or moves) the element of the specified key into the |
| // `btree_map`. If the returned bool is true, insertion took place, and if |
| // it's false, assignment took place. |
| // |
| // iterator insert_or_assign(const_iterator hint, |
| // const key_type& k, M&& obj): |
| // iterator insert_or_assign(const_iterator hint, key_type&& k, M&& obj): |
| // |
| // Inserts/Assigns (or moves) the element of the specified key into the |
| // `btree_map` using the position of `hint` as a non-binding suggestion |
| // for where to begin the insertion search. |
| using Base::insert_or_assign; |
| |
| // btree_map::emplace() |
| // |
| // Inserts an element of the specified value by constructing it in-place |
| // within the `btree_map`, provided that no element with the given key |
| // already exists. |
| // |
| // The element may be constructed even if there already is an element with the |
| // key in the container, in which case the newly constructed element will be |
| // destroyed immediately. Prefer `try_emplace()` unless your key is not |
| // copyable or moveable. |
| // |
| // If an insertion occurs, any references, pointers, or iterators are |
| // invalidated. |
| using Base::emplace; |
| |
| // btree_map::emplace_hint() |
| // |
| // Inserts an element of the specified value by constructing it in-place |
| // within the `btree_map`, using the position of `hint` as a non-binding |
| // suggestion for where to begin the insertion search, and only inserts |
| // provided that no element with the given key already exists. |
| // |
| // The element may be constructed even if there already is an element with the |
| // key in the container, in which case the newly constructed element will be |
| // destroyed immediately. Prefer `try_emplace()` unless your key is not |
| // copyable or moveable. |
| // |
| // If an insertion occurs, any references, pointers, or iterators are |
| // invalidated. |
| using Base::emplace_hint; |
| |
| // btree_map::try_emplace() |
| // |
| // Inserts an element of the specified value by constructing it in-place |
| // within the `btree_map`, provided that no element with the given key |
| // already exists. Unlike `emplace()`, if an element with the given key |
| // already exists, we guarantee that no element is constructed. |
| // |
| // If an insertion occurs, any references, pointers, or iterators are |
| // invalidated. |
| // |
| // Overloads are listed below. |
| // |
| // std::pair<iterator, bool> try_emplace(const key_type& k, Args&&... args): |
| // std::pair<iterator, bool> try_emplace(key_type&& k, Args&&... args): |
| // |
| // Inserts (via copy or move) the element of the specified key into the |
| // `btree_map`. |
| // |
| // iterator try_emplace(const_iterator hint, |
| // const key_type& k, Args&&... args): |
| // iterator try_emplace(const_iterator hint, key_type&& k, Args&&... args): |
| // |
| // Inserts (via copy or move) the element of the specified key into the |
| // `btree_map` using the position of `hint` as a non-binding suggestion |
| // for where to begin the insertion search. |
| using Base::try_emplace; |
| |
| // btree_map::extract() |
| // |
| // Extracts the indicated element, erasing it in the process, and returns it |
| // as a C++17-compatible node handle. Overloads are listed below. |
| // |
| // node_type extract(const_iterator position): |
| // |
| // Extracts the element at the indicated position and returns a node handle |
| // owning that extracted data. |
| // |
| // template <typename K> node_type extract(const K& k): |
| // |
| // Extracts the element with the key matching the passed key value and |
| // returns a node handle owning that extracted data. If the `btree_map` |
| // does not contain an element with a matching key, this function returns an |
| // empty node handle. |
| // |
| // NOTE: when compiled in an earlier version of C++ than C++17, |
| // `node_type::key()` returns a const reference to the key instead of a |
| // mutable reference. We cannot safely return a mutable reference without |
| // std::launder (which is not available before C++17). |
| // |
| // NOTE: In this context, `node_type` refers to the C++17 concept of a |
| // move-only type that owns and provides access to the elements in associative |
| // containers (https://en.cppreference.com/w/cpp/container/node_handle). |
| // It does NOT refer to the data layout of the underlying btree. |
| using Base::extract; |
| |
| // btree_map::merge() |
| // |
| // Extracts elements from a given `source` btree_map into this |
| // `btree_map`. If the destination `btree_map` already contains an |
| // element with an equivalent key, that element is not extracted. |
| using Base::merge; |
| |
| // btree_map::swap(btree_map& other) |
| // |
| // Exchanges the contents of this `btree_map` with those of the `other` |
| // btree_map, avoiding invocation of any move, copy, or swap operations on |
| // individual elements. |
| // |
| // All iterators and references on the `btree_map` remain valid, excepting |
| // for the past-the-end iterator, which is invalidated. |
| using Base::swap; |
| |
| // btree_map::at() |
| // |
| // Returns a reference to the mapped value of the element with key equivalent |
| // to the passed key. |
| using Base::at; |
| |
| // btree_map::contains() |
| // |
| // template <typename K> bool contains(const K& key) const: |
| // |
| // Determines whether an element comparing equal to the given `key` exists |
| // within the `btree_map`, returning `true` if so or `false` otherwise. |
| // |
| // Supports heterogeneous lookup, provided that the map has a compatible |
| // heterogeneous comparator. |
| using Base::contains; |
| |
| // btree_map::count() |
| // |
| // template <typename K> size_type count(const K& key) const: |
| // |
| // Returns the number of elements comparing equal to the given `key` within |
| // the `btree_map`. Note that this function will return either `1` or `0` |
| // since duplicate elements are not allowed within a `btree_map`. |
| // |
| // Supports heterogeneous lookup, provided that the map has a compatible |
| // heterogeneous comparator. |
| using Base::count; |
| |
| // btree_map::equal_range() |
| // |
| // Returns a half-open range [first, last), defined by a `std::pair` of two |
| // iterators, containing all elements with the passed key in the `btree_map`. |
| using Base::equal_range; |
| |
| // btree_map::find() |
| // |
| // template <typename K> iterator find(const K& key): |
| // template <typename K> const_iterator find(const K& key) const: |
| // |
| // Finds an element with the passed `key` within the `btree_map`. |
| // |
| // Supports heterogeneous lookup, provided that the map has a compatible |
| // heterogeneous comparator. |
| using Base::find; |
| |
| // btree_map::lower_bound() |
| // |
| // template <typename K> iterator lower_bound(const K& key): |
| // template <typename K> const_iterator lower_bound(const K& key) const: |
| // |
| // Finds the first element with a key that is not less than `key` within the |
| // `btree_map`. |
| // |
| // Supports heterogeneous lookup, provided that the map has a compatible |
| // heterogeneous comparator. |
| using Base::lower_bound; |
| |
| // btree_map::upper_bound() |
| // |
| // template <typename K> iterator upper_bound(const K& key): |
| // template <typename K> const_iterator upper_bound(const K& key) const: |
| // |
| // Finds the first element with a key that is greater than `key` within the |
| // `btree_map`. |
| // |
| // Supports heterogeneous lookup, provided that the map has a compatible |
| // heterogeneous comparator. |
| using Base::upper_bound; |
| |
| // btree_map::operator[]() |
| // |
| // Returns a reference to the value mapped to the passed key within the |
| // `btree_map`, performing an `insert()` if the key does not already |
| // exist. |
| // |
| // If an insertion occurs, any references, pointers, or iterators are |
| // invalidated. Otherwise iterators are not affected and references are not |
| // invalidated. Overloads are listed below. |
| // |
| // T& operator[](key_type&& key): |
| // T& operator[](const key_type& key): |
| // |
| // Inserts a value_type object constructed in-place if the element with the |
| // given key does not exist. |
| using Base::operator[]; |
| |
| // btree_map::get_allocator() |
| // |
| // Returns the allocator function associated with this `btree_map`. |
| using Base::get_allocator; |
| |
| // btree_map::key_comp(); |
| // |
| // Returns the key comparator associated with this `btree_map`. |
| using Base::key_comp; |
| |
| // btree_map::value_comp(); |
| // |
| // Returns the value comparator associated with this `btree_map`. |
| using Base::value_comp; |
| }; |
| |
| // absl::swap(absl::btree_map<>, absl::btree_map<>) |
| // |
| // Swaps the contents of two `absl::btree_map` containers. |
| template <typename K, typename V, typename C, typename A> |
| void swap(btree_map<K, V, C, A> &x, btree_map<K, V, C, A> &y) { |
| return x.swap(y); |
| } |
| |
| // absl::erase_if(absl::btree_map<>, Pred) |
| // |
| // Erases all elements that satisfy the predicate pred from the container. |
| // Returns the number of erased elements. |
| template <typename K, typename V, typename C, typename A, typename Pred> |
| typename btree_map<K, V, C, A>::size_type erase_if( |
| btree_map<K, V, C, A> &map, Pred pred) { |
| return container_internal::btree_access::erase_if(map, std::move(pred)); |
| } |
| |
| // absl::btree_multimap |
| // |
| // An `absl::btree_multimap<K, V>` is an ordered associative container of |
| // keys and associated values designed to be a more efficient replacement for |
| // `std::multimap` (in most cases). Unlike `absl::btree_map`, a B-tree multimap |
| // allows multiple elements with equivalent keys. |
| // |
| // Keys are sorted using an (optional) comparison function, which defaults to |
| // `std::less<K>`. |
| // |
| // An `absl::btree_multimap<K, V>` uses a default allocator of |
| // `std::allocator<std::pair<const K, V>>` to allocate (and deallocate) |
| // nodes, and construct and destruct values within those nodes. You may |
| // instead specify a custom allocator `A` (which in turn requires specifying a |
| // custom comparator `C`) as in `absl::btree_multimap<K, V, C, A>`. |
| // |
| template <typename Key, typename Value, typename Compare = std::less<Key>, |
| typename Alloc = std::allocator<std::pair<const Key, Value>>> |
| class btree_multimap |
| : public container_internal::btree_multimap_container< |
| container_internal::btree<container_internal::map_params< |
| Key, Value, Compare, Alloc, /*TargetNodeSize=*/256, |
| /*IsMulti=*/true>>> { |
| using Base = typename btree_multimap::btree_multimap_container; |
| |
| public: |
| // Constructors and Assignment Operators |
| // |
| // A `btree_multimap` supports the same overload set as `std::multimap` |
| // for construction and assignment: |
| // |
| // * Default constructor |
| // |
| // absl::btree_multimap<int, std::string> map1; |
| // |
| // * Initializer List constructor |
| // |
| // absl::btree_multimap<int, std::string> map2 = |
| // {{1, "huey"}, {2, "dewey"}, {3, "louie"},}; |
| // |
| // * Copy constructor |
| // |
| // absl::btree_multimap<int, std::string> map3(map2); |
| // |
| // * Copy assignment operator |
| // |
| // absl::btree_multimap<int, std::string> map4; |
| // map4 = map3; |
| // |
| // * Move constructor |
| // |
| // // Move is guaranteed efficient |
| // absl::btree_multimap<int, std::string> map5(std::move(map4)); |
| // |
| // * Move assignment operator |
| // |
| // // May be efficient if allocators are compatible |
| // absl::btree_multimap<int, std::string> map6; |
| // map6 = std::move(map5); |
| // |
| // * Range constructor |
| // |
| // std::vector<std::pair<int, std::string>> v = {{1, "a"}, {2, "b"}}; |
| // absl::btree_multimap<int, std::string> map7(v.begin(), v.end()); |
| btree_multimap() {} |
| using Base::Base; |
| |
| // btree_multimap::begin() |
| // |
| // Returns an iterator to the beginning of the `btree_multimap`. |
| using Base::begin; |
| |
| // btree_multimap::cbegin() |
| // |
| // Returns a const iterator to the beginning of the `btree_multimap`. |
| using Base::cbegin; |
| |
| // btree_multimap::end() |
| // |
| // Returns an iterator to the end of the `btree_multimap`. |
| using Base::end; |
| |
| // btree_multimap::cend() |
| // |
| // Returns a const iterator to the end of the `btree_multimap`. |
| using Base::cend; |
| |
| // btree_multimap::empty() |
| // |
| // Returns whether or not the `btree_multimap` is empty. |
| using Base::empty; |
| |
| // btree_multimap::max_size() |
| // |
| // Returns the largest theoretical possible number of elements within a |
| // `btree_multimap` under current memory constraints. This value can be |
| // thought of as the largest value of `std::distance(begin(), end())` for a |
| // `btree_multimap<Key, T>`. |
| using Base::max_size; |
| |
| // btree_multimap::size() |
| // |
| // Returns the number of elements currently within the `btree_multimap`. |
| using Base::size; |
| |
| // btree_multimap::clear() |
| // |
| // Removes all elements from the `btree_multimap`. Invalidates any references, |
| // pointers, or iterators referring to contained elements. |
| using Base::clear; |
| |
| // btree_multimap::erase() |
| // |
| // Erases elements within the `btree_multimap`. If an erase occurs, any |
| // references, pointers, or iterators are invalidated. |
| // Overloads are listed below. |
| // |
| // iterator erase(iterator position): |
| // iterator erase(const_iterator position): |
| // |
| // Erases the element at `position` of the `btree_multimap`, returning |
| // the iterator pointing to the element after the one that was erased |
| // (or end() if none exists). |
| // |
| // iterator erase(const_iterator first, const_iterator last): |
| // |
| // Erases the elements in the open interval [`first`, `last`), returning |
| // the iterator pointing to the element after the interval that was erased |
| // (or end() if none exists). |
| // |
| // template <typename K> size_type erase(const K& key): |
| // |
| // Erases the elements matching the key, if any exist, returning the |
| // number of elements erased. |
| using Base::erase; |
| |
| // btree_multimap::insert() |
| // |
| // Inserts an element of the specified value into the `btree_multimap`, |
| // returning an iterator pointing to the newly inserted element. |
| // Any references, pointers, or iterators are invalidated. Overloads are |
| // listed below. |
| // |
| // iterator insert(const value_type& value): |
| // |
| // Inserts a value into the `btree_multimap`, returning an iterator to the |
| // inserted element. |
| // |
| // iterator insert(value_type&& value): |
| // |
| // Inserts a moveable value into the `btree_multimap`, returning an iterator |
| // to the inserted element. |
| // |
| // iterator insert(const_iterator hint, const value_type& value): |
| // iterator insert(const_iterator hint, value_type&& value): |
| // |
| // Inserts a value, using the position of `hint` as a non-binding suggestion |
| // for where to begin the insertion search. Returns an iterator to the |
| // inserted element. |
| // |
| // void insert(InputIterator first, InputIterator last): |
| // |
| // Inserts a range of values [`first`, `last`). |
| // |
| // void insert(std::initializer_list<init_type> ilist): |
| // |
| // Inserts the elements within the initializer list `ilist`. |
| using Base::insert; |
| |
| // btree_multimap::emplace() |
| // |
| // Inserts an element of the specified value by constructing it in-place |
| // within the `btree_multimap`. Any references, pointers, or iterators are |
| // invalidated. |
| using Base::emplace; |
| |
| // btree_multimap::emplace_hint() |
| // |
| // Inserts an element of the specified value by constructing it in-place |
| // within the `btree_multimap`, using the position of `hint` as a non-binding |
| // suggestion for where to begin the insertion search. |
| // |
| // Any references, pointers, or iterators are invalidated. |
| using Base::emplace_hint; |
| |
| // btree_multimap::extract() |
| // |
| // Extracts the indicated element, erasing it in the process, and returns it |
| // as a C++17-compatible node handle. Overloads are listed below. |
| // |
| // node_type extract(const_iterator position): |
| // |
| // Extracts the element at the indicated position and returns a node handle |
| // owning that extracted data. |
| // |
| // template <typename K> node_type extract(const K& k): |
| // |
| // Extracts the element with the key matching the passed key value and |
| // returns a node handle owning that extracted data. If the `btree_multimap` |
| // does not contain an element with a matching key, this function returns an |
| // empty node handle. |
| // |
| // NOTE: when compiled in an earlier version of C++ than C++17, |
| // `node_type::key()` returns a const reference to the key instead of a |
| // mutable reference. We cannot safely return a mutable reference without |
| // std::launder (which is not available before C++17). |
| // |
| // NOTE: In this context, `node_type` refers to the C++17 concept of a |
| // move-only type that owns and provides access to the elements in associative |
| // containers (https://en.cppreference.com/w/cpp/container/node_handle). |
| // It does NOT refer to the data layout of the underlying btree. |
| using Base::extract; |
| |
| // btree_multimap::merge() |
| // |
| // Extracts all elements from a given `source` btree_multimap into this |
| // `btree_multimap`. |
| using Base::merge; |
| |
| // btree_multimap::swap(btree_multimap& other) |
| // |
| // Exchanges the contents of this `btree_multimap` with those of the `other` |
| // btree_multimap, avoiding invocation of any move, copy, or swap operations |
| // on individual elements. |
| // |
| // All iterators and references on the `btree_multimap` remain valid, |
| // excepting for the past-the-end iterator, which is invalidated. |
| using Base::swap; |
| |
| // btree_multimap::contains() |
| // |
| // template <typename K> bool contains(const K& key) const: |
| // |
| // Determines whether an element comparing equal to the given `key` exists |
| // within the `btree_multimap`, returning `true` if so or `false` otherwise. |
| // |
| // Supports heterogeneous lookup, provided that the map has a compatible |
| // heterogeneous comparator. |
| using Base::contains; |
| |
| // btree_multimap::count() |
| // |
| // template <typename K> size_type count(const K& key) const: |
| // |
| // Returns the number of elements comparing equal to the given `key` within |
| // the `btree_multimap`. |
| // |
| // Supports heterogeneous lookup, provided that the map has a compatible |
| // heterogeneous comparator. |
| using Base::count; |
| |
| // btree_multimap::equal_range() |
| // |
| // Returns a half-open range [first, last), defined by a `std::pair` of two |
| // iterators, containing all elements with the passed key in the |
| // `btree_multimap`. |
| using Base::equal_range; |
| |
| // btree_multimap::find() |
| // |
| // template <typename K> iterator find(const K& key): |
| // template <typename K> const_iterator find(const K& key) const: |
| // |
| // Finds an element with the passed `key` within the `btree_multimap`. |
| // |
| // Supports heterogeneous lookup, provided that the map has a compatible |
| // heterogeneous comparator. |
| using Base::find; |
| |
| // btree_multimap::lower_bound() |
| // |
| // template <typename K> iterator lower_bound(const K& key): |
| // template <typename K> const_iterator lower_bound(const K& key) const: |
| // |
| // Finds the first element with a key that is not less than `key` within the |
| // `btree_multimap`. |
| // |
| // Supports heterogeneous lookup, provided that the map has a compatible |
| // heterogeneous comparator. |
| using Base::lower_bound; |
| |
| // btree_multimap::upper_bound() |
| // |
| // template <typename K> iterator upper_bound(const K& key): |
| // template <typename K> const_iterator upper_bound(const K& key) const: |
| // |
| // Finds the first element with a key that is greater than `key` within the |
| // `btree_multimap`. |
| // |
| // Supports heterogeneous lookup, provided that the map has a compatible |
| // heterogeneous comparator. |
| using Base::upper_bound; |
| |
| // btree_multimap::get_allocator() |
| // |
| // Returns the allocator function associated with this `btree_multimap`. |
| using Base::get_allocator; |
| |
| // btree_multimap::key_comp(); |
| // |
| // Returns the key comparator associated with this `btree_multimap`. |
| using Base::key_comp; |
| |
| // btree_multimap::value_comp(); |
| // |
| // Returns the value comparator associated with this `btree_multimap`. |
| using Base::value_comp; |
| }; |
| |
| // absl::swap(absl::btree_multimap<>, absl::btree_multimap<>) |
| // |
| // Swaps the contents of two `absl::btree_multimap` containers. |
| template <typename K, typename V, typename C, typename A> |
| void swap(btree_multimap<K, V, C, A> &x, btree_multimap<K, V, C, A> &y) { |
| return x.swap(y); |
| } |
| |
| // absl::erase_if(absl::btree_multimap<>, Pred) |
| // |
| // Erases all elements that satisfy the predicate pred from the container. |
| // Returns the number of erased elements. |
| template <typename K, typename V, typename C, typename A, typename Pred> |
| typename btree_multimap<K, V, C, A>::size_type erase_if( |
| btree_multimap<K, V, C, A> &map, Pred pred) { |
| return container_internal::btree_access::erase_if(map, std::move(pred)); |
| } |
| |
| namespace container_internal { |
| |
| // A parameters structure for holding the type parameters for a btree_map. |
| // Compare and Alloc should be nothrow copy-constructible. |
| template <typename Key, typename Data, typename Compare, typename Alloc, |
| int TargetNodeSize, bool IsMulti> |
| struct map_params : common_params<Key, Compare, Alloc, TargetNodeSize, IsMulti, |
| /*IsMap=*/true, map_slot_policy<Key, Data>> { |
| using super_type = typename map_params::common_params; |
| using mapped_type = Data; |
| // This type allows us to move keys when it is safe to do so. It is safe |
| // for maps in which value_type and mutable_value_type are layout compatible. |
| using slot_policy = typename super_type::slot_policy; |
| using slot_type = typename super_type::slot_type; |
| using value_type = typename super_type::value_type; |
| using init_type = typename super_type::init_type; |
| |
| template <typename V> |
| static auto key(const V &value) -> decltype(value.first) { |
| return value.first; |
| } |
| static const Key &key(const slot_type *s) { return slot_policy::key(s); } |
| static const Key &key(slot_type *s) { return slot_policy::key(s); } |
| // For use in node handle. |
| static auto mutable_key(slot_type *s) |
| -> decltype(slot_policy::mutable_key(s)) { |
| return slot_policy::mutable_key(s); |
| } |
| static mapped_type &value(value_type *value) { return value->second; } |
| }; |
| |
| } // namespace container_internal |
| |
| ABSL_NAMESPACE_END |
| } // namespace absl |
| |
| #endif // ABSL_CONTAINER_BTREE_MAP_H_ |