118 lines
1.9 KiB
C++
118 lines
1.9 KiB
C++
//
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// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2020
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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#pragma once
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#include "td/utils/common.h"
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namespace td {
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struct ListNode {
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ListNode *next;
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ListNode *prev;
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ListNode() {
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clear();
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}
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~ListNode() {
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remove();
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}
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ListNode(const ListNode &) = delete;
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ListNode &operator=(const ListNode &) = delete;
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ListNode(ListNode &&other) {
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if (other.empty()) {
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clear();
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} else {
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init_from(std::move(other));
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}
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}
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ListNode &operator=(ListNode &&other) {
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if (this == &other) {
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return *this;
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}
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this->remove();
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if (!other.empty()) {
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init_from(std::move(other));
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}
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return *this;
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}
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void connect(ListNode *to) {
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CHECK(to != nullptr);
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next = to;
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to->prev = this;
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}
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void remove() {
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prev->connect(next);
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clear();
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}
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void put(ListNode *other) {
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DCHECK(other->empty());
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put_unsafe(other);
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}
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void put_back(ListNode *other) {
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DCHECK(other->empty());
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prev->connect(other);
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other->connect(this);
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}
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ListNode *get() {
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ListNode *result = prev;
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if (result == this) {
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return nullptr;
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}
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result->prev->connect(this);
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result->clear();
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// this->connect(result->next);
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return result;
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}
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bool empty() const {
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return next == this;
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}
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ListNode *begin() {
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return next;
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}
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ListNode *end() {
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return this;
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}
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ListNode *get_next() {
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return next;
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}
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ListNode *get_prev() {
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return prev;
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}
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protected:
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void clear() {
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next = this;
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prev = this;
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}
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void init_from(ListNode &&other) {
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ListNode *head = other.prev;
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other.remove();
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head->put_unsafe(this);
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}
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void put_unsafe(ListNode *other) {
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other->connect(next);
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this->connect(other);
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}
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};
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} // namespace td
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