serenity/AK/CircularDeque.h

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/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/CircularQueue.h>
#include <AK/Types.h>
namespace AK {
template<typename T, size_t Capacity>
class CircularDeque : public CircularQueue<T, Capacity> {
public:
template<typename U = T>
void enqueue_begin(U&& value)
{
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auto const new_head = (this->m_head - 1 + Capacity) % Capacity;
auto& slot = this->elements()[new_head];
if (this->m_size == Capacity)
slot.~T();
else
++this->m_size;
new (&slot) T(forward<U>(value));
this->m_head = new_head;
}
T dequeue_end()
{
VERIFY(!this->is_empty());
auto& slot = this->elements()[(this->m_head + this->m_size - 1) % Capacity];
T value = move(slot);
slot.~T();
this->m_size--;
return value;
}
};
}
#if USING_AK_GLOBALLY
using AK::CircularDeque;
#endif