dynarmic/src/common/intrusive_list.h
Lioncash f2bf795876 intrusive_list: Interface changes
- Remove the root pointer from iterators.

This is unnecessary, since the only way to get a valid iterator is
either from a node itself (it transiently becomes an iterator via the
underlying interface), or through the iterator interface for the list.
This should also result in better code generation, as each increment or
decrement of an iterator is now branchless.

- Remove iterator_to

This is actually a pretty dangerous function, since it would immediately
create an iterator into the list using the given item, even if it's not
actually part of the list. This was only left around due to lack of
type handling around constructors.

- Add other overloads for erase() and remove()

Now handles iterators, pointers, and references.
2016-08-28 20:56:40 +01:00

378 lines
11 KiB
C++

/* This file is part of the dynarmic project.
* Copyright (c) 2016 MerryMage
* This software may be used and distributed according to the terms of the GNU
* General Public License version 2 or any later version.
*/
#pragma once
#include <iterator>
#include <memory>
#include <type_traits>
#include "common/assert.h"
#include "common/common_types.h"
namespace Dynarmic {
namespace Common {
template <typename T> class IntrusiveList;
template <typename T> class IntrusiveListIterator;
template <typename T>
class IntrusiveListNode {
public:
bool IsSentinel() const {
return is_sentinel;
}
protected:
IntrusiveListNode* next = nullptr;
IntrusiveListNode* prev = nullptr;
bool is_sentinel = false;
friend class IntrusiveList<T>;
friend class IntrusiveListIterator<T>;
friend class IntrusiveListIterator<const T>;
};
template <typename T>
class IntrusiveListSentinel final : public IntrusiveListNode<T>
{
using IntrusiveListNode<T>::next;
using IntrusiveListNode<T>::prev;
using IntrusiveListNode<T>::is_sentinel;
public:
IntrusiveListSentinel() {
next = this;
prev = this;
is_sentinel = true;
}
};
template <typename T>
class IntrusiveListIterator {
public:
using iterator_category = std::bidirectional_iterator_tag;
using difference_type = std::ptrdiff_t;
using value_type = T;
using pointer = value_type*;
using const_pointer = const value_type*;
using reference = value_type&;
using const_reference = const value_type&;
// If value_type is const, we want "const IntrusiveListNode<value_type>", not "const IntrusiveListNode<const value_type>"
using node_type = std::conditional_t<std::is_const<value_type>::value,
const IntrusiveListNode<std::remove_const_t<value_type>>,
IntrusiveListNode<value_type>>;
using node_pointer = node_type*;
using node_reference = node_type&;
IntrusiveListIterator() = default;
IntrusiveListIterator(const IntrusiveListIterator& other) = default;
IntrusiveListIterator& operator=(const IntrusiveListIterator& other) = default;
explicit IntrusiveListIterator(node_pointer list_node) : node(list_node) {
}
explicit IntrusiveListIterator(pointer data) : node(data) {
}
explicit IntrusiveListIterator(reference data) : node(&data) {
}
IntrusiveListIterator& operator++() {
node = node->next;
return *this;
}
IntrusiveListIterator& operator--() {
node = node->prev;
return *this;
}
IntrusiveListIterator operator++(int) {
IntrusiveListIterator it(*this);
++*this;
return it;
}
IntrusiveListIterator operator--(int) {
IntrusiveListIterator it(*this);
--*this;
return it;
}
bool operator==(const IntrusiveListIterator& other) const {
return node == other.node;
}
bool operator!=(const IntrusiveListIterator& other) const {
return !operator==(other);
}
reference operator*() const {
DEBUG_ASSERT(!node->IsSentinel());
return static_cast<reference>(*node);
}
pointer operator->() const {
return std::addressof(operator*());
}
node_pointer AsNodePointer() const {
return node;
}
private:
friend class IntrusiveList<T>;
node_pointer node = nullptr;
};
template <typename T>
class IntrusiveList {
public:
using difference_type = std::ptrdiff_t;
using size_type = std::size_t;
using value_type = T;
using pointer = value_type*;
using const_pointer = const value_type*;
using reference = value_type&;
using const_reference = const value_type&;
using iterator = IntrusiveListIterator<value_type>;
using const_iterator = IntrusiveListIterator<const value_type>;
using reverse_iterator = std::reverse_iterator<iterator>;
using const_reverse_iterator = std::reverse_iterator<const_iterator>;
/**
* Inserts a node at the given location indicated by an iterator.
*
* @param location The location to insert the node.
* @param new_node The node to add.
*/
iterator insert(iterator location, pointer new_node) {
return insert_before(location, new_node);
}
/**
* Inserts a node at the given location, moving the previous
* node occupant ahead of the one inserted.
*
* @param location The location to insert the new node.
* @param new_node The node to insert into the list.
*/
iterator insert_before(iterator location, pointer new_node) {
auto existing_node = location.AsNodePointer();
new_node->next = existing_node;
new_node->prev = existing_node->prev;
existing_node->prev->next = new_node;
existing_node->prev = new_node;
return iterator(new_node);
}
/**
* Inserts a new node into the list ahead of the position indicated.
*
* @param position Location to insert the node in front of.
* @param new_node The node to be inserted into the list.
*/
iterator insert_after(iterator position, pointer new_node) {
if (empty())
return insert(begin(), new_node);
return insert(++position, new_node);
}
/**
* Add an entry to the start of the list.
* @param node Node to add to the list.
*/
void push_front(pointer node) {
insert(begin(), node);
}
/**
* Add an entry to the end of the list
* @param node Node to add to the list.
*/
void push_back(pointer node) {
insert(end(), node);
}
/**
* Erases the node at the front of the list.
* @note Must not be called on an empty list.
*/
void pop_front() {
DEBUG_ASSERT(!empty());
erase(begin());
}
/**
* Erases the node at the back of the list.
* @note Must not be called on an empty list.
*/
void pop_back() {
DEBUG_ASSERT(!empty());
erase(--end());
}
/**
* Removes a node from this list
* @param node An iterator that points to the node to remove from list.
*/
pointer remove(iterator& it) {
DEBUG_ASSERT(it != end());
pointer node = &*it++;
node->prev->next = node->next;
node->next->prev = node->prev;
#if !defined(NDEBUG)
node->next = nullptr;
node->prev = nullptr;
#endif
return node;
}
/**
* Removes a node from this list
* @param node A constant iterator that points to the node to remove from list.
*/
pointer remove(const iterator& it) {
iterator copy = it;
return remove(it);
}
/**
* Removes a node from this list.
* @param node A pointer to the node to remove.
*/
pointer remove(pointer node) {
return remove(iterator(node));
}
/**
* Removes a node from this list.
* @param node A reference to the node to remove.
*/
pointer remove(reference node) {
return remove(iterator(node));
}
/**
* Is this list empty?
* @returns true if there are no nodes in this list.
*/
bool empty() const {
return root->next == root.get();
}
/**
* Gets the total number of elements within this list.
* @return the number of elements in this list.
*/
size_type size() const {
return static_cast<size_type>(std::distance(begin(), end()));
}
/**
* Retrieves a reference to the node at the front of the list.
* @note Must not be called on an empty list.
*/
reference front() {
DEBUG_ASSERT(!empty());
return *begin();
}
/**
* Retrieves a constant reference to the node at the front of the list.
* @note Must not be called on an empty list.
*/
const_reference front() const {
DEBUG_ASSERT(!empty());
return *begin();
}
/**
* Retrieves a reference to the node at the back of the list.
* @note Must not be called on an empty list.
*/
reference back() {
DEBUG_ASSERT(!empty());
return *--end();
}
/**
* Retrieves a constant reference to the node at the back of the list.
* @note Must not be called on an empty list.
*/
const_reference back() const {
DEBUG_ASSERT(!empty());
return *--end();
}
// Iterator interface
iterator begin() { return iterator(root->next); }
const_iterator begin() const { return const_iterator(root->next); }
const_iterator cbegin() const { return begin(); }
iterator end() { return iterator(root.get()); }
const_iterator end() const { return const_iterator(root.get()); }
const_iterator cend() const { return end(); }
reverse_iterator rbegin() { return reverse_iterator(end()); }
const_reverse_iterator rbegin() const { return const_reverse_iterator(end()); }
const_reverse_iterator crbegin() const { return rbegin(); }
reverse_iterator rend() { return reverse_iterator(begin()); }
const_reverse_iterator rend() const { return const_reverse_iterator(begin()); }
const_reverse_iterator crend() const { return rend(); }
/**
* Erases a node from the list, indicated by an iterator.
* @param it The iterator that points to the node to erase.
*/
iterator erase(iterator it) {
remove(it);
return it;
}
/**
* Erases a node from this list.
* @param node A pointer to the node to erase from this list.
*/
iterator erase(pointer node) {
return erase(iterator(node));
}
/**
* Erases a node from this list.
* @param node A reference to the node to erase from this list.
*/
iterator erase(reference node) {
return erase(iterator(node));
}
/**
* Exchanges contents of this list with another list instance.
* @param other The other list to swap with.
*/
void swap(IntrusiveList& other) {
root.swap(other.root);
}
private:
std::shared_ptr<IntrusiveListNode<T>> root = std::make_shared<IntrusiveListSentinel<T>>();
};
/**
* Exchanges contents of an intrusive list with another intrusive list.
* @tparam T The type of data being kept track of by the lists.
* @param lhs The first list.
* @param rhs The second list.
*/
template <typename T>
void swap(IntrusiveList<T>& lhs, IntrusiveList<T>& rhs) {
lhs.swap(rhs);
}
} // namespace Common
} // namespace Dynarmic