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812 lines
28 KiB
812 lines
28 KiB
// Copyright 2018 The Abseil Authors. |
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// |
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// Licensed under the Apache License, Version 2.0 (the "License"); |
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// you may not use this file except in compliance with the License. |
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// You may obtain a copy of the License at |
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// |
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// https://www.apache.org/licenses/LICENSE-2.0 |
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// |
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// Unless required by applicable law or agreed to in writing, software |
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// distributed under the License is distributed on an "AS IS" BASIS, |
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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// See the License for the specific language governing permissions and |
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// limitations under the License. |
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// |
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// ----------------------------------------------------------------------------- |
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// File: btree_set.h |
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// ----------------------------------------------------------------------------- |
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// |
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// This header file defines B-tree sets: sorted associative containers of |
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// values. |
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// |
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// * `absl::btree_set<>` |
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// * `absl::btree_multiset<>` |
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// |
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// These B-tree types are similar to the corresponding types in the STL |
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// (`std::set` and `std::multiset`) and generally conform to the STL interfaces |
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// of those types. However, because they are implemented using B-trees, they |
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// are more efficient in most situations. |
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// |
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// Unlike `std::set` and `std::multiset`, which are commonly implemented using |
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// red-black tree nodes, B-tree sets use more generic B-tree nodes able to hold |
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// multiple values per node. Holding multiple values per node often makes |
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// B-tree sets perform better than their `std::set` counterparts, because |
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// multiple entries can be checked within the same cache hit. |
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// |
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// However, these types should not be considered drop-in replacements for |
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// `std::set` and `std::multiset` as there are some API differences, which are |
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// noted in this header file. The most consequential differences with respect to |
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// migrating to b-tree from the STL types are listed in the next paragraph. |
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// Other API differences are minor. |
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// |
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// Importantly, insertions and deletions may invalidate outstanding iterators, |
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// pointers, and references to elements. Such invalidations are typically only |
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// an issue if insertion and deletion operations are interleaved with the use of |
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// more than one iterator, pointer, or reference simultaneously. For this |
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// reason, `insert()` and `erase()` return a valid iterator at the current |
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// position. |
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#ifndef ABSL_CONTAINER_BTREE_SET_H_ |
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#define ABSL_CONTAINER_BTREE_SET_H_ |
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#include "absl/container/internal/btree.h" // IWYU pragma: export |
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#include "absl/container/internal/btree_container.h" // IWYU pragma: export |
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namespace absl { |
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ABSL_NAMESPACE_BEGIN |
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namespace container_internal { |
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template <typename Key> |
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struct set_slot_policy; |
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template <typename Key, typename Compare, typename Alloc, int TargetNodeSize, |
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bool Multi> |
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struct set_params; |
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} // namespace container_internal |
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// absl::btree_set<> |
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// |
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// An `absl::btree_set<K>` is an ordered associative container of unique key |
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// values designed to be a more efficient replacement for `std::set` (in most |
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// cases). |
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// |
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// Keys are sorted using an (optional) comparison function, which defaults to |
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// `std::less<K>`. |
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// |
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// An `absl::btree_set<K>` uses a default allocator of `std::allocator<K>` to |
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// allocate (and deallocate) nodes, and construct and destruct values within |
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// those nodes. You may instead specify a custom allocator `A` (which in turn |
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// requires specifying a custom comparator `C`) as in |
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// `absl::btree_set<K, C, A>`. |
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// |
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template <typename Key, typename Compare = std::less<Key>, |
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typename Alloc = std::allocator<Key>> |
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class btree_set |
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: public container_internal::btree_set_container< |
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container_internal::btree<container_internal::set_params< |
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Key, Compare, Alloc, /*TargetNodeSize=*/256, |
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/*Multi=*/false>>> { |
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using Base = typename btree_set::btree_set_container; |
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public: |
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// Constructors and Assignment Operators |
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// |
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// A `btree_set` supports the same overload set as `std::set` |
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// for construction and assignment: |
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// |
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// * Default constructor |
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// |
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// absl::btree_set<std::string> set1; |
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// |
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// * Initializer List constructor |
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// |
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// absl::btree_set<std::string> set2 = |
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// {{"huey"}, {"dewey"}, {"louie"},}; |
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// |
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// * Copy constructor |
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// |
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// absl::btree_set<std::string> set3(set2); |
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// |
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// * Copy assignment operator |
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// |
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// absl::btree_set<std::string> set4; |
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// set4 = set3; |
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// |
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// * Move constructor |
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// |
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// // Move is guaranteed efficient |
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// absl::btree_set<std::string> set5(std::move(set4)); |
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// |
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// * Move assignment operator |
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// |
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// // May be efficient if allocators are compatible |
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// absl::btree_set<std::string> set6; |
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// set6 = std::move(set5); |
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// |
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// * Range constructor |
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// |
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// std::vector<std::string> v = {"a", "b"}; |
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// absl::btree_set<std::string> set7(v.begin(), v.end()); |
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btree_set() {} |
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using Base::Base; |
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// btree_set::begin() |
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// |
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// Returns an iterator to the beginning of the `btree_set`. |
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using Base::begin; |
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// btree_set::cbegin() |
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// |
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// Returns a const iterator to the beginning of the `btree_set`. |
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using Base::cbegin; |
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// btree_set::end() |
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// |
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// Returns an iterator to the end of the `btree_set`. |
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using Base::end; |
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// btree_set::cend() |
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// |
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// Returns a const iterator to the end of the `btree_set`. |
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using Base::cend; |
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|
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// btree_set::empty() |
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// |
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// Returns whether or not the `btree_set` is empty. |
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using Base::empty; |
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|
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// btree_set::max_size() |
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// |
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// Returns the largest theoretical possible number of elements within a |
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// `btree_set` under current memory constraints. This value can be thought |
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// of as the largest value of `std::distance(begin(), end())` for a |
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// `btree_set<Key>`. |
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using Base::max_size; |
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// btree_set::size() |
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// |
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// Returns the number of elements currently within the `btree_set`. |
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using Base::size; |
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// btree_set::clear() |
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// |
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// Removes all elements from the `btree_set`. Invalidates any references, |
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// pointers, or iterators referring to contained elements. |
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using Base::clear; |
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// btree_set::erase() |
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// |
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// Erases elements within the `btree_set`. Overloads are listed below. |
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// |
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// iterator erase(iterator position): |
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// iterator erase(const_iterator position): |
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// |
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// Erases the element at `position` of the `btree_set`, returning |
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// the iterator pointing to the element after the one that was erased |
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// (or end() if none exists). |
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// |
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// iterator erase(const_iterator first, const_iterator last): |
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// |
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// Erases the elements in the open interval [`first`, `last`), returning |
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// the iterator pointing to the element after the interval that was erased |
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// (or end() if none exists). |
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// |
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// template <typename K> size_type erase(const K& key): |
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// |
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// Erases the element with the matching key, if it exists, returning the |
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// number of elements erased (0 or 1). |
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using Base::erase; |
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// btree_set::insert() |
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// |
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// Inserts an element of the specified value into the `btree_set`, |
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// returning an iterator pointing to the newly inserted element, provided that |
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// an element with the given key does not already exist. If an insertion |
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// occurs, any references, pointers, or iterators are invalidated. |
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// Overloads are listed below. |
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// |
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// std::pair<iterator,bool> insert(const value_type& value): |
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// |
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// Inserts a value into the `btree_set`. Returns a pair consisting of an |
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// iterator to the inserted element (or to the element that prevented the |
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// insertion) and a bool denoting whether the insertion took place. |
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// |
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// std::pair<iterator,bool> insert(value_type&& value): |
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// |
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// Inserts a moveable value into the `btree_set`. Returns a pair |
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// consisting of an iterator to the inserted element (or to the element that |
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// prevented the insertion) and a bool denoting whether the insertion took |
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// place. |
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// |
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// iterator insert(const_iterator hint, const value_type& value): |
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// iterator insert(const_iterator hint, value_type&& value): |
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// |
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// Inserts a value, using the position of `hint` as a non-binding suggestion |
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// for where to begin the insertion search. Returns an iterator to the |
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// inserted element, or to the existing element that prevented the |
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// insertion. |
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// |
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// void insert(InputIterator first, InputIterator last): |
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// |
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// Inserts a range of values [`first`, `last`). |
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// |
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// void insert(std::initializer_list<init_type> ilist): |
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// |
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// Inserts the elements within the initializer list `ilist`. |
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using Base::insert; |
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// btree_set::emplace() |
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// |
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// Inserts an element of the specified value by constructing it in-place |
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// within the `btree_set`, provided that no element with the given key |
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// already exists. |
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// |
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// The element may be constructed even if there already is an element with the |
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// key in the container, in which case the newly constructed element will be |
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// destroyed immediately. |
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// |
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// If an insertion occurs, any references, pointers, or iterators are |
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// invalidated. |
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using Base::emplace; |
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// btree_set::emplace_hint() |
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// |
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// Inserts an element of the specified value by constructing it in-place |
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// within the `btree_set`, using the position of `hint` as a non-binding |
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// suggestion for where to begin the insertion search, and only inserts |
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// provided that no element with the given key already exists. |
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// |
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// The element may be constructed even if there already is an element with the |
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// key in the container, in which case the newly constructed element will be |
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// destroyed immediately. |
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// |
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// If an insertion occurs, any references, pointers, or iterators are |
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// invalidated. |
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using Base::emplace_hint; |
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// btree_set::extract() |
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// |
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// Extracts the indicated element, erasing it in the process, and returns it |
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// as a C++17-compatible node handle. Overloads are listed below. |
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// |
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// node_type extract(const_iterator position): |
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// |
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// Extracts the element at the indicated position and returns a node handle |
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// owning that extracted data. |
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// |
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// template <typename K> node_type extract(const K& k): |
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// |
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// Extracts the element with the key matching the passed key value and |
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// returns a node handle owning that extracted data. If the `btree_set` |
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// does not contain an element with a matching key, this function returns an |
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// empty node handle. |
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// |
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// NOTE: In this context, `node_type` refers to the C++17 concept of a |
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// move-only type that owns and provides access to the elements in associative |
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// containers (https://en.cppreference.com/w/cpp/container/node_handle). |
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// It does NOT refer to the data layout of the underlying btree. |
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using Base::extract; |
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// btree_set::merge() |
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// |
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// Extracts elements from a given `source` btree_set into this |
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// `btree_set`. If the destination `btree_set` already contains an |
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// element with an equivalent key, that element is not extracted. |
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using Base::merge; |
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// btree_set::swap(btree_set& other) |
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// |
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// Exchanges the contents of this `btree_set` with those of the `other` |
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// btree_set, avoiding invocation of any move, copy, or swap operations on |
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// individual elements. |
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// |
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// All iterators and references on the `btree_set` remain valid, excepting |
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// for the past-the-end iterator, which is invalidated. |
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using Base::swap; |
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// btree_set::contains() |
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// |
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// template <typename K> bool contains(const K& key) const: |
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// |
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// Determines whether an element comparing equal to the given `key` exists |
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// within the `btree_set`, returning `true` if so or `false` otherwise. |
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// |
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// Supports heterogeneous lookup, provided that the set has a compatible |
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// heterogeneous comparator. |
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using Base::contains; |
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// btree_set::count() |
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// |
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// template <typename K> size_type count(const K& key) const: |
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// |
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// Returns the number of elements comparing equal to the given `key` within |
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// the `btree_set`. Note that this function will return either `1` or `0` |
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// since duplicate elements are not allowed within a `btree_set`. |
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// |
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// Supports heterogeneous lookup, provided that the set has a compatible |
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// heterogeneous comparator. |
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using Base::count; |
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// btree_set::equal_range() |
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// |
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// Returns a closed range [first, last], defined by a `std::pair` of two |
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// iterators, containing all elements with the passed key in the |
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// `btree_set`. |
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using Base::equal_range; |
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// btree_set::find() |
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// |
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// template <typename K> iterator find(const K& key): |
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// template <typename K> const_iterator find(const K& key) const: |
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// |
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// Finds an element with the passed `key` within the `btree_set`. |
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// |
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// Supports heterogeneous lookup, provided that the set has a compatible |
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// heterogeneous comparator. |
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using Base::find; |
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// btree_set::lower_bound() |
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// |
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// template <typename K> iterator lower_bound(const K& key): |
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// template <typename K> const_iterator lower_bound(const K& key) const: |
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// |
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// Finds the first element that is not less than `key` within the `btree_set`. |
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// |
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// Supports heterogeneous lookup, provided that the set has a compatible |
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// heterogeneous comparator. |
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using Base::lower_bound; |
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// btree_set::upper_bound() |
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// |
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// template <typename K> iterator upper_bound(const K& key): |
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// template <typename K> const_iterator upper_bound(const K& key) const: |
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// |
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// Finds the first element that is greater than `key` within the `btree_set`. |
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// |
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// Supports heterogeneous lookup, provided that the set has a compatible |
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// heterogeneous comparator. |
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using Base::upper_bound; |
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// btree_set::get_allocator() |
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// |
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// Returns the allocator function associated with this `btree_set`. |
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using Base::get_allocator; |
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// btree_set::key_comp(); |
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// |
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// Returns the key comparator associated with this `btree_set`. |
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using Base::key_comp; |
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// btree_set::value_comp(); |
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// |
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// Returns the value comparator associated with this `btree_set`. The keys to |
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// sort the elements are the values themselves, therefore `value_comp` and its |
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// sibling member function `key_comp` are equivalent. |
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using Base::value_comp; |
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}; |
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// absl::swap(absl::btree_set<>, absl::btree_set<>) |
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// |
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// Swaps the contents of two `absl::btree_set` containers. |
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template <typename K, typename C, typename A> |
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void swap(btree_set<K, C, A> &x, btree_set<K, C, A> &y) { |
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return x.swap(y); |
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} |
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// absl::erase_if(absl::btree_set<>, Pred) |
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// |
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// Erases all elements that satisfy the predicate pred from the container. |
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// Returns the number of erased elements. |
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template <typename K, typename C, typename A, typename Pred> |
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typename btree_set<K, C, A>::size_type erase_if(btree_set<K, C, A> &set, |
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Pred pred) { |
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const auto initial_size = set.size(); |
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for (auto it = set.begin(); it != set.end();) { |
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if (pred(*it)) { |
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it = set.erase(it); |
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} else { |
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++it; |
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} |
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} |
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return initial_size - set.size(); |
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} |
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// absl::btree_multiset<> |
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// |
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// An `absl::btree_multiset<K>` is an ordered associative container of |
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// keys and associated values designed to be a more efficient replacement |
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// for `std::multiset` (in most cases). Unlike `absl::btree_set`, a B-tree |
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// multiset allows equivalent elements. |
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// |
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// Keys are sorted using an (optional) comparison function, which defaults to |
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// `std::less<K>`. |
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// |
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// An `absl::btree_multiset<K>` uses a default allocator of `std::allocator<K>` |
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// to allocate (and deallocate) nodes, and construct and destruct values within |
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// those nodes. You may instead specify a custom allocator `A` (which in turn |
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// requires specifying a custom comparator `C`) as in |
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// `absl::btree_multiset<K, C, A>`. |
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// |
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template <typename Key, typename Compare = std::less<Key>, |
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typename Alloc = std::allocator<Key>> |
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class btree_multiset |
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: public container_internal::btree_multiset_container< |
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container_internal::btree<container_internal::set_params< |
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Key, Compare, Alloc, /*TargetNodeSize=*/256, |
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/*Multi=*/true>>> { |
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using Base = typename btree_multiset::btree_multiset_container; |
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public: |
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// Constructors and Assignment Operators |
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// |
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// A `btree_multiset` supports the same overload set as `std::set` |
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// for construction and assignment: |
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// |
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// * Default constructor |
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// |
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// absl::btree_multiset<std::string> set1; |
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// |
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// * Initializer List constructor |
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// |
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// absl::btree_multiset<std::string> set2 = |
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// {{"huey"}, {"dewey"}, {"louie"},}; |
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// |
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// * Copy constructor |
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// |
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// absl::btree_multiset<std::string> set3(set2); |
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// |
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// * Copy assignment operator |
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// |
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// absl::btree_multiset<std::string> set4; |
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// set4 = set3; |
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// |
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// * Move constructor |
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// |
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// // Move is guaranteed efficient |
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// absl::btree_multiset<std::string> set5(std::move(set4)); |
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// |
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// * Move assignment operator |
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// |
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// // May be efficient if allocators are compatible |
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// absl::btree_multiset<std::string> set6; |
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// set6 = std::move(set5); |
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// |
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// * Range constructor |
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// |
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// std::vector<std::string> v = {"a", "b"}; |
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// absl::btree_multiset<std::string> set7(v.begin(), v.end()); |
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btree_multiset() {} |
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using Base::Base; |
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// btree_multiset::begin() |
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// |
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// Returns an iterator to the beginning of the `btree_multiset`. |
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using Base::begin; |
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|
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// btree_multiset::cbegin() |
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// |
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// Returns a const iterator to the beginning of the `btree_multiset`. |
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using Base::cbegin; |
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|
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// btree_multiset::end() |
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// |
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// Returns an iterator to the end of the `btree_multiset`. |
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using Base::end; |
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// btree_multiset::cend() |
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// |
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// Returns a const iterator to the end of the `btree_multiset`. |
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using Base::cend; |
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// btree_multiset::empty() |
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// |
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// Returns whether or not the `btree_multiset` is empty. |
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using Base::empty; |
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|
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// btree_multiset::max_size() |
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// |
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// Returns the largest theoretical possible number of elements within a |
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// `btree_multiset` under current memory constraints. This value can be |
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// thought of as the largest value of `std::distance(begin(), end())` for a |
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// `btree_multiset<Key>`. |
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using Base::max_size; |
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// btree_multiset::size() |
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// |
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// Returns the number of elements currently within the `btree_multiset`. |
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using Base::size; |
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|
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// btree_multiset::clear() |
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// |
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// Removes all elements from the `btree_multiset`. Invalidates any references, |
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// pointers, or iterators referring to contained elements. |
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using Base::clear; |
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|
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// btree_multiset::erase() |
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// |
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// Erases elements within the `btree_multiset`. Overloads are listed below. |
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// |
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// iterator erase(iterator position): |
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// iterator erase(const_iterator position): |
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// |
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// Erases the element at `position` of the `btree_multiset`, returning |
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// the iterator pointing to the element after the one that was erased |
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// (or end() if none exists). |
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// |
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// iterator erase(const_iterator first, const_iterator last): |
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// |
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// Erases the elements in the open interval [`first`, `last`), returning |
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// the iterator pointing to the element after the interval that was erased |
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// (or end() if none exists). |
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// |
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// template <typename K> size_type erase(const K& key): |
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// |
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// Erases the elements matching the key, if any exist, returning the |
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// number of elements erased. |
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using Base::erase; |
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|
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// btree_multiset::insert() |
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// |
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// Inserts an element of the specified value into the `btree_multiset`, |
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// returning an iterator pointing to the newly inserted element. |
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// Any references, pointers, or iterators are invalidated. Overloads are |
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// listed below. |
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// |
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// iterator insert(const value_type& value): |
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// |
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// Inserts a value into the `btree_multiset`, returning an iterator to the |
|
// inserted element. |
|
// |
|
// iterator insert(value_type&& value): |
|
// |
|
// Inserts a moveable value into the `btree_multiset`, 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_multiset::emplace() |
|
// |
|
// Inserts an element of the specified value by constructing it in-place |
|
// within the `btree_multiset`. Any references, pointers, or iterators are |
|
// invalidated. |
|
using Base::emplace; |
|
|
|
// btree_multiset::emplace_hint() |
|
// |
|
// Inserts an element of the specified value by constructing it in-place |
|
// within the `btree_multiset`, 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_multiset::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_multiset` |
|
// does not contain an element with a matching key, this function returns an |
|
// empty node handle. |
|
// |
|
// 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_multiset::merge() |
|
// |
|
// Extracts all elements from a given `source` btree_multiset into this |
|
// `btree_multiset`. |
|
using Base::merge; |
|
|
|
// btree_multiset::swap(btree_multiset& other) |
|
// |
|
// Exchanges the contents of this `btree_multiset` with those of the `other` |
|
// btree_multiset, avoiding invocation of any move, copy, or swap operations |
|
// on individual elements. |
|
// |
|
// All iterators and references on the `btree_multiset` remain valid, |
|
// excepting for the past-the-end iterator, which is invalidated. |
|
using Base::swap; |
|
|
|
// btree_multiset::contains() |
|
// |
|
// template <typename K> bool contains(const K& key) const: |
|
// |
|
// Determines whether an element comparing equal to the given `key` exists |
|
// within the `btree_multiset`, returning `true` if so or `false` otherwise. |
|
// |
|
// Supports heterogeneous lookup, provided that the set has a compatible |
|
// heterogeneous comparator. |
|
using Base::contains; |
|
|
|
// btree_multiset::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_multiset`. |
|
// |
|
// Supports heterogeneous lookup, provided that the set has a compatible |
|
// heterogeneous comparator. |
|
using Base::count; |
|
|
|
// btree_multiset::equal_range() |
|
// |
|
// Returns a closed range [first, last], defined by a `std::pair` of two |
|
// iterators, containing all elements with the passed key in the |
|
// `btree_multiset`. |
|
using Base::equal_range; |
|
|
|
// btree_multiset::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_multiset`. |
|
// |
|
// Supports heterogeneous lookup, provided that the set has a compatible |
|
// heterogeneous comparator. |
|
using Base::find; |
|
|
|
// btree_multiset::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 that is not less than `key` within the |
|
// `btree_multiset`. |
|
// |
|
// Supports heterogeneous lookup, provided that the set has a compatible |
|
// heterogeneous comparator. |
|
using Base::lower_bound; |
|
|
|
// btree_multiset::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 that is greater than `key` within the |
|
// `btree_multiset`. |
|
// |
|
// Supports heterogeneous lookup, provided that the set has a compatible |
|
// heterogeneous comparator. |
|
using Base::upper_bound; |
|
|
|
// btree_multiset::get_allocator() |
|
// |
|
// Returns the allocator function associated with this `btree_multiset`. |
|
using Base::get_allocator; |
|
|
|
// btree_multiset::key_comp(); |
|
// |
|
// Returns the key comparator associated with this `btree_multiset`. |
|
using Base::key_comp; |
|
|
|
// btree_multiset::value_comp(); |
|
// |
|
// Returns the value comparator associated with this `btree_multiset`. The |
|
// keys to sort the elements are the values themselves, therefore `value_comp` |
|
// and its sibling member function `key_comp` are equivalent. |
|
using Base::value_comp; |
|
}; |
|
|
|
// absl::swap(absl::btree_multiset<>, absl::btree_multiset<>) |
|
// |
|
// Swaps the contents of two `absl::btree_multiset` containers. |
|
template <typename K, typename C, typename A> |
|
void swap(btree_multiset<K, C, A> &x, btree_multiset<K, C, A> &y) { |
|
return x.swap(y); |
|
} |
|
|
|
// absl::erase_if(absl::btree_multiset<>, Pred) |
|
// |
|
// Erases all elements that satisfy the predicate pred from the container. |
|
// Returns the number of erased elements. |
|
template <typename K, typename C, typename A, typename Pred> |
|
typename btree_multiset<K, C, A>::size_type erase_if( |
|
btree_multiset<K, C, A> & set, Pred pred) { |
|
const auto initial_size = set.size(); |
|
for (auto it = set.begin(); it != set.end();) { |
|
if (pred(*it)) { |
|
it = set.erase(it); |
|
} else { |
|
++it; |
|
} |
|
} |
|
return initial_size - set.size(); |
|
} |
|
|
|
namespace container_internal { |
|
|
|
// This type implements the necessary functions from the |
|
// absl::container_internal::slot_type interface for btree_(multi)set. |
|
template <typename Key> |
|
struct set_slot_policy { |
|
using slot_type = Key; |
|
using value_type = Key; |
|
using mutable_value_type = Key; |
|
|
|
static value_type &element(slot_type *slot) { return *slot; } |
|
static const value_type &element(const slot_type *slot) { return *slot; } |
|
|
|
template <typename Alloc, class... Args> |
|
static void construct(Alloc *alloc, slot_type *slot, Args &&...args) { |
|
absl::allocator_traits<Alloc>::construct(*alloc, slot, |
|
std::forward<Args>(args)...); |
|
} |
|
|
|
template <typename Alloc> |
|
static void construct(Alloc *alloc, slot_type *slot, slot_type *other) { |
|
absl::allocator_traits<Alloc>::construct(*alloc, slot, std::move(*other)); |
|
} |
|
|
|
template <typename Alloc> |
|
static void destroy(Alloc *alloc, slot_type *slot) { |
|
absl::allocator_traits<Alloc>::destroy(*alloc, slot); |
|
} |
|
|
|
template <typename Alloc> |
|
static void swap(Alloc * /*alloc*/, slot_type *a, slot_type *b) { |
|
using std::swap; |
|
swap(*a, *b); |
|
} |
|
|
|
template <typename Alloc> |
|
static void move(Alloc * /*alloc*/, slot_type *src, slot_type *dest) { |
|
*dest = std::move(*src); |
|
} |
|
}; |
|
|
|
// A parameters structure for holding the type parameters for a btree_set. |
|
// Compare and Alloc should be nothrow copy-constructible. |
|
template <typename Key, typename Compare, typename Alloc, int TargetNodeSize, |
|
bool Multi> |
|
struct set_params : common_params<Key, Compare, Alloc, TargetNodeSize, Multi, |
|
set_slot_policy<Key>> { |
|
using value_type = Key; |
|
using slot_type = typename set_params::common_params::slot_type; |
|
using value_compare = |
|
typename set_params::common_params::original_key_compare; |
|
using is_map_container = std::false_type; |
|
|
|
template <typename V> |
|
static const V &key(const V &value) { |
|
return value; |
|
} |
|
static const Key &key(const slot_type *slot) { return *slot; } |
|
static const Key &key(slot_type *slot) { return *slot; } |
|
}; |
|
|
|
} // namespace container_internal |
|
|
|
ABSL_NAMESPACE_END |
|
} // namespace absl |
|
|
|
#endif // ABSL_CONTAINER_BTREE_SET_H_
|
|
|