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tdlib-fork/tdutils/td/utils/List.h

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