CircularQueue

A generic FIFO queue with a fixed capacity. Once full, each new item silently drops the oldest. Perfect for log tails, telemetry buffers, or any "last N things" scenario.

Usage

using Servus.Collections;

var buffer = new CircularQueue<string>(3);

buffer.Enqueue("A");
buffer.Enqueue("B");
buffer.Enqueue("C");
// Queue: [A, B, C]

buffer.Enqueue("D");
// Queue: [B, C, D] — "A" was automatically removed

if (buffer.TryDequeue(out var item))
{
    Console.WriteLine(item); // "B"
}

Reading without consuming

Items gives you an IEnumerable<T> snapshot without mutating the queue:

foreach (var entry in buffer.Items)
{
    Log.Information("Tail entry: {Entry}", entry);
}

API

public class CircularQueue<T>
{
    public CircularQueue(int capacity);

    public int Count { get; }
    public int Capacity { get; }
    public IEnumerable<T> Items { get; }

    public void Enqueue(T item);
    public bool TryDequeue(out T item);
}

When to use it

• Log tails — keep the last N log entries in memory for display on a diagnostics page.
• Rolling metrics — last N latencies or error messages for a running average.
• Undo stacks — limited-depth history where old entries should simply fall off.