69 lines
1.8 KiB
C++
69 lines
1.8 KiB
C++
/*
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* Copyright (c) Facebook, Inc. and its affiliates.
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*
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* Licensed under the Apache License Version 2.0 with LLVM Exceptions
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* https://llvm.org/LICENSE.txt
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#pragma once
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#include <utility>
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namespace unifex {
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template<typename T, T* T::*Next>
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class intrusive_stack {
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public:
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intrusive_stack() : head_(nullptr) {}
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intrusive_stack(intrusive_stack&& other) noexcept : head_(std::exchange(other.head_, nullptr)) {}
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intrusive_stack(const intrusive_stack&) = delete;
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intrusive_stack& operator=(const intrusive_stack&) = delete;
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intrusive_stack& operator=(intrusive_stack&&) = delete;
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~intrusive_stack() {
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UNIFEX_ASSERT(empty());
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}
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// Adopt an existing linked-list as a stack.
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static intrusive_stack adopt(T* head) noexcept {
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intrusive_stack stack;
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stack.head_ = head;
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return stack;
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}
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T* release() noexcept {
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return std::exchange(head_, nullptr);
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}
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[[nodiscard]] bool empty() const noexcept {
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return head_ == nullptr;
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}
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void push_front(T* item) noexcept {
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item->*Next = head_;
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head_ = item;
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}
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[[nodiscard]] T* pop_front() noexcept {
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UNIFEX_ASSERT(!empty());
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T* item = head_;
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head_ = item->*Next;
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return item;
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}
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private:
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T* head_;
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};
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} // namespace unifex
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