AimRT/install_x64/include/unifex/detail/intrusive_heap.hpp
2025-01-12 19:51:34 +08:00

116 lines
2.8 KiB
C++

/*
* Copyright (c) Facebook, Inc. and its affiliates.
*
* Licensed under the Apache License Version 2.0 with LLVM Exceptions
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* https://llvm.org/LICENSE.txt
*
* 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.
*/
#pragma once
#include <unifex/detail/prologue.hpp>
namespace unifex {
// A doubly-linked intrusive list maintained in ascending order of the 'SortKey'
// field of the list items.
template <typename T, T* T::*Next, T* T::*Prev, typename Key, Key T::*SortKey>
class intrusive_heap {
public:
intrusive_heap() noexcept : head_(nullptr) {}
~intrusive_heap() {
T* item = head_;
if (item != nullptr) {
UNIFEX_ASSERT(item->*Prev == nullptr);
}
while (item != nullptr) {
if (item->*Next != nullptr) {
UNIFEX_ASSERT(item->*Next->*Prev == item);
}
item = item->*Next;
}
UNIFEX_ASSERT(empty());
}
bool empty() const noexcept {
return head_ == nullptr;
}
T* top() const noexcept {
UNIFEX_ASSERT(!empty());
return head_;
}
T* pop() noexcept {
UNIFEX_ASSERT(!empty());
T* item = head_;
head_ = item->*Next;
if (head_ != nullptr) {
head_->*Prev = nullptr;
}
return item;
}
void insert(T* item) noexcept {
// Simple insertion sort to insert item in the right place in the list
// to keep the list sorted by 'item->*SortKey'.
// TODO: Replace this with a non-toy data-structure.
if (head_ == nullptr) {
head_ = item;
item->*Next = nullptr;
item->*Prev = nullptr;
} else if (item->*SortKey < head_->*SortKey) {
item->*Next = head_;
item->*Prev = nullptr;
head_->*Prev = item;
head_ = item;
} else {
auto* insertAfter = head_;
while (insertAfter->*Next != nullptr &&
insertAfter->*Next->*SortKey <= item->*SortKey) {
insertAfter = insertAfter->*Next;
}
auto* insertBefore = insertAfter->*Next;
item->*Prev = insertAfter;
item->*Next = insertBefore;
insertAfter->*Next = item;
if (insertBefore != nullptr) {
insertBefore->*Prev = item;
}
}
}
void remove(T* item) noexcept {
auto* prev = item->*Prev;
auto* next = item->*Next;
if (prev != nullptr) {
prev->*Next = next;
} else {
UNIFEX_ASSERT(head_ == item);
head_ = next;
}
if (next != nullptr) {
next->*Prev = prev;
}
}
private:
T* head_;
};
} // namespace unifex
#include <unifex/detail/epilogue.hpp>