179 lines
6.4 KiB
C++
179 lines
6.4 KiB
C++
/*
|
|
* Copyright (c) 2021 The WebRTC project authors. All Rights Reserved.
|
|
*
|
|
* Use of this source code is governed by a BSD-style license
|
|
* that can be found in the LICENSE file in the root of the source
|
|
* tree. An additional intellectual property rights grant can be found
|
|
* in the file PATENTS. All contributing project authors may
|
|
* be found in the AUTHORS file in the root of the source tree.
|
|
*/
|
|
|
|
// This implementation is borrowed from Chromium.
|
|
|
|
#ifndef RTC_BASE_CONTAINERS_FLAT_SET_H_
|
|
#define RTC_BASE_CONTAINERS_FLAT_SET_H_
|
|
|
|
#include <functional>
|
|
#include <vector>
|
|
|
|
#include "rtc_base/containers/flat_tree.h" // IWYU pragma: export
|
|
#include "rtc_base/containers/identity.h"
|
|
|
|
namespace webrtc {
|
|
|
|
// flat_set is a container with a std::set-like interface that stores its
|
|
// contents in a sorted container, by default a vector.
|
|
//
|
|
// Its implementation mostly tracks the corresponding standardization proposal
|
|
// https://wg21.link/P1222.
|
|
//
|
|
//
|
|
// PROS
|
|
//
|
|
// - Good memory locality.
|
|
// - Low overhead, especially for smaller sets.
|
|
// - Performance is good for more workloads than you might expect (see
|
|
// //base/containers/README.md in Chromium repository)
|
|
// - Supports C++14 set interface.
|
|
//
|
|
// CONS
|
|
//
|
|
// - Inserts and removals are O(n).
|
|
//
|
|
// IMPORTANT NOTES
|
|
//
|
|
// - Iterators are invalidated across mutations.
|
|
// - If possible, construct a flat_set in one operation by inserting into
|
|
// a container and moving that container into the flat_set constructor.
|
|
// - For multiple removals use base::EraseIf() which is O(n) rather than
|
|
// O(n * removed_items).
|
|
//
|
|
// QUICK REFERENCE
|
|
//
|
|
// Most of the core functionality is inherited from flat_tree. Please see
|
|
// flat_tree.h for more details for most of these functions. As a quick
|
|
// reference, the functions available are:
|
|
//
|
|
// Constructors (inputs need not be sorted):
|
|
// flat_set(const flat_set&);
|
|
// flat_set(flat_set&&);
|
|
// flat_set(InputIterator first, InputIterator last,
|
|
// const Compare& compare = Compare());
|
|
// flat_set(const container_type& items,
|
|
// const Compare& compare = Compare());
|
|
// flat_set(container_type&& items,
|
|
// const Compare& compare = Compare()); // Re-use storage.
|
|
// flat_set(std::initializer_list<value_type> ilist,
|
|
// const Compare& comp = Compare());
|
|
//
|
|
// Constructors (inputs need to be sorted):
|
|
// flat_set(sorted_unique_t,
|
|
// InputIterator first, InputIterator last,
|
|
// const Compare& compare = Compare());
|
|
// flat_set(sorted_unique_t,
|
|
// const container_type& items,
|
|
// const Compare& compare = Compare());
|
|
// flat_set(sorted_unique_t,
|
|
// container_type&& items,
|
|
// const Compare& compare = Compare()); // Re-use storage.
|
|
// flat_set(sorted_unique_t,
|
|
// std::initializer_list<value_type> ilist,
|
|
// const Compare& comp = Compare());
|
|
//
|
|
// Assignment functions:
|
|
// flat_set& operator=(const flat_set&);
|
|
// flat_set& operator=(flat_set&&);
|
|
// flat_set& operator=(initializer_list<Key>);
|
|
//
|
|
// Memory management functions:
|
|
// void reserve(size_t);
|
|
// size_t capacity() const;
|
|
// void shrink_to_fit();
|
|
//
|
|
// Size management functions:
|
|
// void clear();
|
|
// size_t size() const;
|
|
// size_t max_size() const;
|
|
// bool empty() const;
|
|
//
|
|
// Iterator functions:
|
|
// iterator begin();
|
|
// const_iterator begin() const;
|
|
// const_iterator cbegin() const;
|
|
// iterator end();
|
|
// const_iterator end() const;
|
|
// const_iterator cend() const;
|
|
// reverse_iterator rbegin();
|
|
// const reverse_iterator rbegin() const;
|
|
// const_reverse_iterator crbegin() const;
|
|
// reverse_iterator rend();
|
|
// const_reverse_iterator rend() const;
|
|
// const_reverse_iterator crend() const;
|
|
//
|
|
// Insert and accessor functions:
|
|
// pair<iterator, bool> insert(const key_type&);
|
|
// pair<iterator, bool> insert(key_type&&);
|
|
// void insert(InputIterator first, InputIterator last);
|
|
// iterator insert(const_iterator hint, const key_type&);
|
|
// iterator insert(const_iterator hint, key_type&&);
|
|
// pair<iterator, bool> emplace(Args&&...);
|
|
// iterator emplace_hint(const_iterator, Args&&...);
|
|
//
|
|
// Underlying type functions:
|
|
// container_type extract() &&;
|
|
// void replace(container_type&&);
|
|
//
|
|
// Erase functions:
|
|
// iterator erase(iterator);
|
|
// iterator erase(const_iterator);
|
|
// iterator erase(const_iterator first, const_iterator& last);
|
|
// template <typename K> size_t erase(const K& key);
|
|
//
|
|
// Comparators (see std::set documentation).
|
|
// key_compare key_comp() const;
|
|
// value_compare value_comp() const;
|
|
//
|
|
// Search functions:
|
|
// template <typename K> size_t count(const K&) const;
|
|
// template <typename K> iterator find(const K&);
|
|
// template <typename K> const_iterator find(const K&) const;
|
|
// template <typename K> bool contains(const K&) const;
|
|
// template <typename K> pair<iterator, iterator> equal_range(K&);
|
|
// template <typename K> iterator lower_bound(const K&);
|
|
// template <typename K> const_iterator lower_bound(const K&) const;
|
|
// template <typename K> iterator upper_bound(const K&);
|
|
// template <typename K> const_iterator upper_bound(const K&) const;
|
|
//
|
|
// General functions:
|
|
// void swap(flat_set&);
|
|
//
|
|
// Non-member operators:
|
|
// bool operator==(const flat_set&, const flat_set);
|
|
// bool operator!=(const flat_set&, const flat_set);
|
|
// bool operator<(const flat_set&, const flat_set);
|
|
// bool operator>(const flat_set&, const flat_set);
|
|
// bool operator>=(const flat_set&, const flat_set);
|
|
// bool operator<=(const flat_set&, const flat_set);
|
|
//
|
|
template <class Key,
|
|
class Compare = std::less<>,
|
|
class Container = std::vector<Key>>
|
|
using flat_set = typename ::webrtc::flat_containers_internal::
|
|
flat_tree<Key, webrtc::identity, Compare, Container>;
|
|
|
|
// ----------------------------------------------------------------------------
|
|
// General operations.
|
|
|
|
// Erases all elements that match predicate. It has O(size) complexity.
|
|
//
|
|
// flat_set<int> numbers;
|
|
// ...
|
|
// EraseIf(numbers, [](int number) { return number % 2 == 1; });
|
|
|
|
// NOLINTNEXTLINE(misc-unused-using-decls)
|
|
using ::webrtc::flat_containers_internal::EraseIf;
|
|
|
|
} // namespace webrtc
|
|
|
|
#endif // RTC_BASE_CONTAINERS_FLAT_SET_H_
|