dolphin/Source/Core/Common/FixedSizeQueue.h

// Copyright 2008 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.

#pragma once

#include <cstddef>

// 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.

// TODO: "inline" storage?

template <class T, int N>
class FixedSizeQueue
{
  T* storage;
  int head;
  int tail;
  int count;  // sacrifice 4 bytes for a simpler implementation. may optimize away in the future.

  // Make copy constructor private for now.
  FixedSizeQueue(FixedSizeQueue& other) {}
public:
  FixedSizeQueue()
  {
    storage = new T[N];
    clear();
  }

  ~FixedSizeQueue() { delete[] storage; }
  void clear()
  {
    head = 0;
    tail = 0;
    count = 0;
  }

  void push(T t)
  {
    storage[tail] = t;
    tail++;
    if (tail == N)
      tail = 0;
    count++;
  }

  void pop()
  {
    head++;
    if (head == N)
      head = 0;
    count--;
  }

  T pop_front()
  {
    const T& temp = storage[head];
    pop();
    return temp;
  }

  T& front() { return storage[head]; }
  const T& front() const { return storage[head]; }
  size_t size() const { return count; }
};