> For the complete documentation index, see [llms.txt](https://mwm5.twelite.info/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://mwm5.twelite.info/master-2/references/basics/tweutils/fixedqueue.md).

# FixedQueue

std::queueは、ブロック単位でのメモリ確保を行い動的にキューのサイズを拡張していきますが、本クラスではメモリサイズを抑制し固定長のキューを実装します。

```cpp
template<typename T>
class FixedQueue : public std::queue<T> { ... };
```

本クラスは`std::queue`を継承しています。

## バッファのブロックサイズ

GCCの場合はバッファのブロックサイズを定義することができます。

本ライブラリでの利用を想定し以下のように64バイトにしています。

```cpp
#if __GNUC__
#define _GLIBCXX_DEQUE_BUF_SIZE 64
     // smaller chunk for deque in GCC, the dafalt size
     // 512bytes are too big for embedded systems.
#endif

#include <deque>
#include <queue>
```

## メソッド

### FixedQueue() - コンストラクタ

```cpp
FixedQueue(std::size_t size)
```

`size`を最大値としてキューを生成します。

### push()

```cpp
bool push(T value)
```

キューに要素を追加します。キューが一杯になると何もせず`false`を返します。

### pop()

```cpp
void pop()
```

キューから要素を削除します。

### front()

```cpp
T& std::queue<T>::front()
```

要素にアクセスします。

### empty()

```cpp
bool std::queue<T>::empty()
```

キューが空の場合`true`を返します。


---

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