1.3.39 #

/// <summary>
/// 环形缓冲区。
/// </summary>
/// <typeparam name="TItem">缓冲区包含的元素类型。</typeparam>
internal class RingBuffer<TItem>
{
    private readonly TItem[] _buffer;
    private int _count;
    private int _first;  // 读指针
    private int _last;   // 写指针

    /// <summary>
    /// 建立一个缓冲区。
    /// </summary>
    /// <param name="n">缓冲区的大小。</param>
    public RingBuffer(int n)
    {
        _buffer = new TItem[n];
        _count = 0;
        _first = 0;
        _last = 0;
    }

    /// <summary>
    /// 检查缓冲区是否已满。
    /// </summary>
    /// <returns></returns>
    public bool IsFull()
    {
        return _count == _buffer.Length;
    }

    /// <summary>
    /// 检查缓冲区是否为空。
    /// </summary>
    /// <returns></returns>
    public bool IsEmpty()
    {
        return _count == 0;
    }

    /// <summary>
    /// 向缓冲区写入数据。
    /// </summary>
    /// <param name="item">要写入的数据。</param>
    public void Write(TItem item)
    {
        if (IsFull())
        {
            throw new OutOfMemoryException("buffer is full");
        }

        _buffer[_last] = item;
        _last = (_last + 1) % _buffer.Length;
        _count++;
    }

    /// <summary>
    /// 从缓冲区读取一个数据。
    /// </summary>
    /// <returns></returns>
    public TItem Read()
    {
        if (IsEmpty())
        {
            throw new InvalidOperationException();
        }

        var temp = _buffer[_first];
        _first = (_first + 1) % _buffer.Length;
        _count--;
        return temp;
    }
}