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// Copyright 2008 Dolphin Emulator Project
// SPDX-License-Identifier: GPL-2.0-or-later
#pragma once
#include <array>
#include <cstddef>
#include <type_traits>
#include <utility>
// STL-look-a-like interface, but name is mixed case to distinguish it clearly from the
// real STL classes.
//
// Not fully featured, no safety checking yet. Add features as needed.
namespace Common
{
template <class T, int N>
class FixedSizeQueue
{
public:
void clear()
{
if constexpr (!std::is_trivial_v<T>)
{
// The clear of non-trivial objects previously used "storage = {}". However, this causes GCC
// to take a very long time to compile the file/function, as well as generating huge amounts
// of debug information (~2GB object file, ~600MB of debug info).
while (count > 0)
pop();
}
head = 0;
tail = 0;
count = 0;
}
void push(T t)
{
if (count == N)
head = (head + 1) % N;
else
count++;
storage[tail] = std::move(t);
tail = (tail + 1) % N;
}
template <class... Args>
void emplace(Args&&... args)
{
if (count == N)
head = (head + 1) % N;
else
count++;
storage[tail] = T(std::forward<Args>(args)...);
tail = (tail + 1) % N;
}
void pop()
{
if constexpr (!std::is_trivial_v<T>)
storage[head] = {};
head = (head + 1) % N;
count--;
}
T pop_front()
{
T temp = std::move(front());
pop();
return temp;
}
T& front() noexcept { return storage[head]; }
const T& front() const noexcept { return storage[head]; }
size_t size() const noexcept { return count; }
bool empty() const noexcept { return size() == 0; }
private:
std::array<T, N> storage{};
int head = 0;
int tail = 0;
// Sacrifice 4 bytes for a simpler implementation. may optimize away in the future.
int count = 0;
};
} // namespace Common
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