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/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef ART_LIBARTBASE_BASE_INTRUSIVE_FORWARD_LIST_H_
#define ART_LIBARTBASE_BASE_INTRUSIVE_FORWARD_LIST_H_
#include <stdint.h>
#include <functional>
#include <iterator>
#include <memory>
#include <type_traits>
#include <android-base/logging.h>
#include "base/casts.h"
#include "base/macros.h"
namespace art {
struct IntrusiveForwardListHook {
IntrusiveForwardListHook() : next_hook(nullptr) { }
explicit IntrusiveForwardListHook(const IntrusiveForwardListHook* hook) : next_hook(hook) { }
// Allow copyable values but do not copy the hook, it is not part of the value.
explicit IntrusiveForwardListHook([[maybe_unused]] const IntrusiveForwardListHook& other)
: next_hook(nullptr) {}
IntrusiveForwardListHook& operator=([[maybe_unused]] const IntrusiveForwardListHook& src) {
return *this;
}
mutable const IntrusiveForwardListHook* next_hook;
};
template <typename Derived, typename Tag = void>
struct IntrusiveForwardListNode : public IntrusiveForwardListHook {
};
template <typename T, IntrusiveForwardListHook T::* NextPtr = &T::hook>
class IntrusiveForwardListMemberHookTraits;
template <typename T, typename Tag = void>
class IntrusiveForwardListBaseHookTraits;
template <typename T,
typename HookTraits = IntrusiveForwardListBaseHookTraits<std::remove_const_t<T>>>
class IntrusiveForwardList;
template <typename T, typename HookTraits>
class IntrusiveForwardListIterator {
public:
using iterator_category = std::forward_iterator_tag;
using value_type = T;
using difference_type = ptrdiff_t;
using pointer = value_type*;
using reference = value_type&;
// Construct/copy/destroy (except the private constructor used by IntrusiveForwardList<>).
IntrusiveForwardListIterator() : hook_(nullptr) { }
IntrusiveForwardListIterator(const IntrusiveForwardListIterator& src) = default;
IntrusiveForwardListIterator& operator=(const IntrusiveForwardListIterator& src) = default;
// Conversion from iterator to const_iterator.
template <typename OtherT,
typename = std::enable_if_t<std::is_same_v<T, const OtherT>>>
IntrusiveForwardListIterator(const IntrusiveForwardListIterator<OtherT, HookTraits>& src) // NOLINT, implicit
: hook_(src.hook_) { }
// Iteration.
IntrusiveForwardListIterator& operator++() {
DCHECK(hook_ != nullptr);
hook_ = hook_->next_hook;
return *this;
}
IntrusiveForwardListIterator operator++(int) {
IntrusiveForwardListIterator tmp(*this);
++*this;
return tmp;
}
// Dereference
T& operator*() const {
DCHECK(hook_ != nullptr);
return *HookTraits::GetValue(hook_);
}
T* operator->() const {
return &**this;
}
private:
explicit IntrusiveForwardListIterator(const IntrusiveForwardListHook* hook) : hook_(hook) { }
const IntrusiveForwardListHook* hook_;
template <typename OtherT, typename OtherTraits>
friend class IntrusiveForwardListIterator;
template <typename OtherT, typename OtherTraits>
friend class IntrusiveForwardList;
template <typename OtherT1, typename OtherT2, typename OtherTraits>
friend std::enable_if_t<std::is_same_v<const OtherT1, const OtherT2>, bool>
operator==(const IntrusiveForwardListIterator<OtherT1, OtherTraits>& lhs,
const IntrusiveForwardListIterator<OtherT2, OtherTraits>& rhs);
};
template <typename T, typename OtherT, typename HookTraits>
std::enable_if_t<std::is_same_v<const T, const OtherT>, bool> operator==(
const IntrusiveForwardListIterator<T, HookTraits>& lhs,
const IntrusiveForwardListIterator<OtherT, HookTraits>& rhs) {
return lhs.hook_ == rhs.hook_;
}
template <typename T, typename OtherT, typename HookTraits>
std::enable_if_t<std::is_same_v<const T, const OtherT>, bool> operator!=(
const IntrusiveForwardListIterator<T, HookTraits>& lhs,
const IntrusiveForwardListIterator<OtherT, HookTraits>& rhs) {
return !(lhs == rhs);
}
// Intrusive version of std::forward_list<>. See also slist<> in Boost.Intrusive.
//
// This class template provides the same interface as std::forward_list<> as long
// as the functions are meaningful for an intrusive container; this excludes emplace
// functions and functions taking an std::initializer_list<> as the container does
// not construct elements.
template <typename T, typename HookTraits>
class IntrusiveForwardList {
public:
using hook_traits = HookTraits;
using value_type = T;
using reference = T&;
using const_reference = const T&;
using pointer = T*;
using const_pointer = const T*;
using iterator = IntrusiveForwardListIterator<T, hook_traits>;
using const_iterator = IntrusiveForwardListIterator<const T, hook_traits>;
// Construct/copy/destroy.
IntrusiveForwardList() = default;
template <typename InputIterator>
IntrusiveForwardList(InputIterator first, InputIterator last) : IntrusiveForwardList() {
insert_after(before_begin(), first, last);
}
IntrusiveForwardList(IntrusiveForwardList&& src) noexcept : first_(src.first_.next_hook) {
src.first_.next_hook = nullptr;
}
IntrusiveForwardList& operator=(const IntrusiveForwardList& src) = delete;
IntrusiveForwardList& operator=(IntrusiveForwardList&& src) noexcept {
IntrusiveForwardList tmp(std::move(src));
tmp.swap(*this);
return *this;
}
~IntrusiveForwardList() = default;
// Iterators.
iterator before_begin() { return iterator(&first_); }
const_iterator before_begin() const { return const_iterator(&first_); }
iterator begin() { return iterator(first_.next_hook); }
const_iterator begin() const { return const_iterator(first_.next_hook); }
iterator end() { return iterator(nullptr); }
const_iterator end() const { return const_iterator(nullptr); }
const_iterator cbefore_begin() const { return const_iterator(&first_); }
const_iterator cbegin() const { return const_iterator(first_.next_hook); }
const_iterator cend() const { return const_iterator(nullptr); }
// Capacity.
bool empty() const { return begin() == end(); }
size_t max_size() { return static_cast<size_t>(-1); }
// Element access.
reference front() { return *begin(); }
const_reference front() const { return *begin(); }
// Modifiers.
template <typename InputIterator>
void assign(InputIterator first, InputIterator last) {
IntrusiveForwardList tmp(first, last);
tmp.swap(*this);
}
void push_front(value_type& value) {
insert_after(before_begin(), value);
}
void pop_front() {
DCHECK(!empty());
erase_after(before_begin());
}
iterator insert_after(const_iterator position, value_type& value) {
const IntrusiveForwardListHook* new_hook = hook_traits::GetHook(&value);
new_hook->next_hook = position.hook_->next_hook;
position.hook_->next_hook = new_hook;
return iterator(new_hook);
}
template <typename InputIterator>
iterator insert_after(const_iterator position, InputIterator first, InputIterator last) {
while (first != last) {
position = insert_after(position, *first++);
}
return iterator(position.hook_);
}
iterator erase_after(const_iterator position) {
const_iterator last = position;
std::advance(last, 2);
return erase_after(position, last);
}
iterator erase_after(const_iterator position, const_iterator last) {
DCHECK(position != last);
position.hook_->next_hook = last.hook_;
return iterator(last.hook_);
}
void swap(IntrusiveForwardList& other) {
std::swap(first_.next_hook, other.first_.next_hook);
}
void clear() {
first_.next_hook = nullptr;
}
// Operations.
void splice_after(const_iterator position, IntrusiveForwardList& src) {
DCHECK(position != end());
splice_after(position, src, src.before_begin(), src.end());
}
void splice_after(const_iterator position, IntrusiveForwardList&& src) {
splice_after(position, src); // Use l-value overload.
}
// Splice the element after `i`.
void splice_after(const_iterator position, IntrusiveForwardList& src, const_iterator i) {
// The standard specifies that this version does nothing if `position == i`
// or `position == ++i`. We must handle the latter here because the overload
// `splice_after(position, src, first, last)` does not allow `position` inside
// the range `(first, last)`.
if (++const_iterator(i) == position) {
return;
}
const_iterator last = i;
std::advance(last, 2);
splice_after(position, src, i, last);
}
// Splice the element after `i`.
void splice_after(const_iterator position, IntrusiveForwardList&& src, const_iterator i) {
splice_after(position, src, i); // Use l-value overload.
}
// Splice elements between `first` and `last`, i.e. open range `(first, last)`.
void splice_after(const_iterator position,
IntrusiveForwardList& src,
const_iterator first,
const_iterator last) {
DCHECK(position != end());
DCHECK(first != last);
if (++const_iterator(first) == last) {
// Nothing to do.
return;
}
// If position is just before end() and last is src.end(), we can finish this quickly.
if (++const_iterator(position) == end() && last == src.end()) {
position.hook_->next_hook = first.hook_->next_hook;
first.hook_->next_hook = nullptr;
return;
}
// Otherwise we need to find the position before last to fix up the hook.
const_iterator before_last = first;
while (++const_iterator(before_last) != last) {
++before_last;
}
// Detach (first, last).
const IntrusiveForwardListHook* first_taken = first.hook_->next_hook;
first.hook_->next_hook = last.hook_;
// Attach the sequence to the new position.
before_last.hook_->next_hook = position.hook_->next_hook;
position.hook_->next_hook = first_taken;
}
// Splice elements between `first` and `last`, i.e. open range `(first, last)`.
void splice_after(const_iterator position,
IntrusiveForwardList&& src,
const_iterator first,
const_iterator last) {
splice_after(position, src, first, last); // Use l-value overload.
}
void remove(const value_type& value) {
remove_if([value](const value_type& v) { return value == v; });
}
template <typename Predicate>
void remove_if(Predicate pred) {
iterator prev = before_begin();
for (iterator current = begin(); current != end(); ++current) {
if (pred(*current)) {
erase_after(prev);
current = prev;
} else {
prev = current;
}
}
}
void unique() {
unique(std::equal_to<value_type>());
}
template <typename BinaryPredicate>
void unique(BinaryPredicate pred) {
if (!empty()) {
iterator prev = begin();
iterator current = prev;
++current;
for (; current != end(); ++current) {
if (pred(*prev, *current)) {
erase_after(prev);
current = prev;
} else {
prev = current;
}
}
}
}
void merge(IntrusiveForwardList& other) {
merge(other, std::less<value_type>());
}
void merge(IntrusiveForwardList&& other) {
merge(other); // Use l-value overload.
}
template <typename Compare>
void merge(IntrusiveForwardList& other, Compare cmp) {
iterator prev = before_begin();
iterator current = begin();
iterator other_prev = other.before_begin();
iterator other_current = other.begin();
while (current != end() && other_current != other.end()) {
if (cmp(*other_current, *current)) {
++other_current;
splice_after(prev, other, other_prev);
++prev;
} else {
prev = current;
++current;
}
DCHECK(++const_iterator(prev) == current);
DCHECK(++const_iterator(other_prev) == other_current);
}
splice_after(prev, other);
}
template <typename Compare>
void merge(IntrusiveForwardList&& other, Compare cmp) {
merge(other, cmp); // Use l-value overload.
}
void sort() {
sort(std::less<value_type>());
}
template <typename Compare>
void sort(Compare cmp) {
size_t n = std::distance(begin(), end());
if (n >= 2u) {
const_iterator middle = before_begin();
std::advance(middle, n / 2u);
IntrusiveForwardList second_half;
second_half.splice_after(second_half.before_begin(), *this, middle, end());
sort(cmp);
second_half.sort(cmp);
merge(second_half, cmp);
}
}
void reverse() {
IntrusiveForwardList reversed;
while (!empty()) {
value_type& value = front();
erase_after(before_begin());
reversed.insert_after(reversed.before_begin(), value);
}
reversed.swap(*this);
}
// Extensions.
bool HasExactlyOneElement() const {
return !empty() && ++begin() == end();
}
size_t SizeSlow() const {
return std::distance(begin(), end());
}
bool ContainsNode(const_reference node) const {
for (auto&& n : *this) {
if (std::addressof(n) == std::addressof(node)) {
return true;
}
}
return false;
}
private:
static IntrusiveForwardListHook* ModifiableHook(const IntrusiveForwardListHook* hook) {
return const_cast<IntrusiveForwardListHook*>(hook);
}
IntrusiveForwardListHook first_;
};
template <typename T, typename HookTraits>
void swap(IntrusiveForwardList<T, HookTraits>& lhs, IntrusiveForwardList<T, HookTraits>& rhs) {
lhs.swap(rhs);
}
template <typename T, typename HookTraits>
bool operator==(const IntrusiveForwardList<T, HookTraits>& lhs,
const IntrusiveForwardList<T, HookTraits>& rhs) {
auto lit = lhs.begin();
auto rit = rhs.begin();
for (; lit != lhs.end() && rit != rhs.end(); ++lit, ++rit) {
if (*lit != *rit) {
return false;
}
}
return lit == lhs.end() && rit == rhs.end();
}
template <typename T, typename HookTraits>
bool operator!=(const IntrusiveForwardList<T, HookTraits>& lhs,
const IntrusiveForwardList<T, HookTraits>& rhs) {
return !(lhs == rhs);
}
template <typename T, typename HookTraits>
bool operator<(const IntrusiveForwardList<T, HookTraits>& lhs,
const IntrusiveForwardList<T, HookTraits>& rhs) {
return std::lexicographical_compare(lhs.begin(), lhs.end(), rhs.begin(), rhs.end());
}
template <typename T, typename HookTraits>
bool operator>(const IntrusiveForwardList<T, HookTraits>& lhs,
const IntrusiveForwardList<T, HookTraits>& rhs) {
return rhs < lhs;
}
template <typename T, typename HookTraits>
bool operator<=(const IntrusiveForwardList<T, HookTraits>& lhs,
const IntrusiveForwardList<T, HookTraits>& rhs) {
return !(rhs < lhs);
}
template <typename T, typename HookTraits>
bool operator>=(const IntrusiveForwardList<T, HookTraits>& lhs,
const IntrusiveForwardList<T, HookTraits>& rhs) {
return !(lhs < rhs);
}
template <typename T, IntrusiveForwardListHook T::* NextPtr>
class IntrusiveForwardListMemberHookTraits {
public:
static const IntrusiveForwardListHook* GetHook(const T* value) {
return &(value->*NextPtr);
}
static T* GetValue(const IntrusiveForwardListHook* hook) {
return reinterpret_cast<T*>(
reinterpret_cast<uintptr_t>(hook) - OFFSETOF_MEMBERPTR(T, NextPtr));
}
};
template <typename T, typename Tag>
class IntrusiveForwardListBaseHookTraits {
public:
static const IntrusiveForwardListHook* GetHook(const T* value) {
// Explicit conversion to the "node" followed by implicit conversion to the "hook".
return static_cast<const IntrusiveForwardListNode<T, Tag>*>(value);
}
static T* GetValue(const IntrusiveForwardListHook* hook) {
return down_cast<T*>(down_cast<IntrusiveForwardListNode<T, Tag>*>(
const_cast<IntrusiveForwardListHook*>(hook)));
}
};
} // namespace art
#endif // ART_LIBARTBASE_BASE_INTRUSIVE_FORWARD_LIST_H_