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These changes are compatible with clang-format 16 and will be mandatory when we eventually bump clang-format version. So, since there are no real downsides, let's commit them now.
137 lines
3.2 KiB
C++
137 lines
3.2 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/Assertions.h>
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#include <AK/Forward.h>
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#include <AK/StdLibExtras.h>
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namespace AK {
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template<typename T, size_t Capacity>
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class CircularQueue {
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public:
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CircularQueue() = default;
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~CircularQueue()
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{
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clear();
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}
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void clear()
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{
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for (size_t i = 0; i < m_size; ++i)
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elements()[(m_head + i) % Capacity].~T();
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m_head = 0;
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m_size = 0;
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}
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bool is_empty() const { return m_size == 0; }
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size_t size() const { return m_size; }
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size_t capacity() const { return Capacity; }
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template<typename U = T>
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void enqueue(U&& value)
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{
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auto& slot = elements()[(m_head + m_size) % Capacity];
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if (m_size == Capacity)
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slot.~T();
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new (&slot) T(forward<U>(value));
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if (m_size == Capacity)
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m_head = (m_head + 1) % Capacity;
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else
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++m_size;
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}
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T dequeue()
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{
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VERIFY(!is_empty());
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auto& slot = elements()[m_head];
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T value = move(slot);
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slot.~T();
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m_head = (m_head + 1) % Capacity;
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--m_size;
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return value;
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}
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T const& at(size_t index) const { return elements()[(m_head + index) % Capacity]; }
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T& at(size_t index) { return elements()[(m_head + index) % Capacity]; }
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T const& first() const { return at(0); }
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T const& last() const { return at(size() - 1); }
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class ConstIterator {
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public:
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bool operator!=(ConstIterator const& other) { return m_index != other.m_index; }
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ConstIterator& operator++()
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{
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++m_index;
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return *this;
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}
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T const& operator*() const { return m_queue.at(m_index); }
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private:
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friend class CircularQueue;
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ConstIterator(CircularQueue const& queue, size_t const index)
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: m_queue(queue)
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, m_index(index)
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{
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}
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CircularQueue const& m_queue;
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size_t m_index { 0 };
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};
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class Iterator {
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public:
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bool operator!=(Iterator const& other) { return m_index != other.m_index; }
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Iterator& operator++()
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{
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++m_index;
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return *this;
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}
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T& operator*() const { return m_queue.at(m_index); }
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private:
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friend class CircularQueue;
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Iterator(CircularQueue& queue, size_t const index)
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: m_queue(queue)
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, m_index(index)
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{
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}
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CircularQueue& m_queue;
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size_t m_index { 0 };
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};
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ConstIterator begin() const { return ConstIterator(*this, 0); }
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ConstIterator end() const { return ConstIterator(*this, size()); }
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Iterator begin() { return Iterator(*this, 0); }
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Iterator end() { return Iterator(*this, size()); }
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size_t head_index() const { return m_head; }
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protected:
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T* elements() { return reinterpret_cast<T*>(m_storage); }
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T const* elements() const { return reinterpret_cast<T const*>(m_storage); }
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friend class ConstIterator;
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alignas(T) u8 m_storage[sizeof(T) * Capacity];
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size_t m_size { 0 };
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size_t m_head { 0 };
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};
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}
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#if USING_AK_GLOBALLY
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using AK::CircularQueue;
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#endif
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