tdlight/tdutils/td/utils/List.h
2022-01-01 03:35:39 +03:00

118 lines
2.0 KiB
C++

//
// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2022
//
// 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) noexcept {
if (other.empty()) {
clear();
} else {
init_from(std::move(other));
}
}
ListNode &operator=(ListNode &&other) noexcept {
if (this == &other) {
return *this;
}
this->remove();
if (!other.empty()) {
init_from(std::move(other));
}
return *this;
}
void connect(ListNode *to) {
CHECK(to != nullptr);
next = to;
to->prev = this;
}
void remove() {
prev->connect(next);
clear();
}
void put(ListNode *other) {
DCHECK(other->empty());
put_unsafe(other);
}
void put_back(ListNode *other) {
DCHECK(other->empty());
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;
}
ListNode *begin() {
return next;
}
ListNode *end() {
return this;
}
ListNode *get_next() {
return next;
}
ListNode *get_prev() {
return prev;
}
protected:
void clear() {
next = this;
prev = this;
}
void init_from(ListNode &&other) {
ListNode *head = other.prev;
other.remove();
head->put_unsafe(this);
}
void put_unsafe(ListNode *other) {
other->connect(next);
this->connect(other);
}
};
} // namespace td