ListPool.cs

using System;
using System.Collections.Generic;


namespace Binocle
{
    /// <summary>
    /// simple static class that can be used to pool Lists
    /// </summary>
    public static class ListPool<T>
    {
        static Queue<List<T>> _objectQueue = new Queue<List<T>>();


        /// <summary>
        /// warms up the cache filling it with a max of cacheCount objects
        /// </summary>
        /// <param name="cacheCount">new cache count</param>
        public static void warmCache(int cacheCount)
        {
            cacheCount -= _objectQueue.Count;
            if (cacheCount > 0)
            {
                for (var i = 0; i < cacheCount; i++)
                    _objectQueue.Enqueue(new List<T>());
            }
        }


        /// <summary>
        /// trims the cache down to cacheCount items
        /// </summary>
        /// <param name="cacheCount">Cache count.</param>
        public static void trimCache(int cacheCount)
        {
            while (cacheCount > _objectQueue.Count)
                _objectQueue.Dequeue();
        }


        /// <summary>
        /// clears out the cache
        /// </summary>
        public static void clearCache()
        {
            _objectQueue.Clear();
        }


        /// <summary>
        /// pops an item off the stack if available creating a new item as necessary
        /// </summary>
        public static List<T> obtain()
        {
            if (_objectQueue.Count > 0)
                return _objectQueue.Dequeue();

            return new List<T>();
        }


        /// <summary>
        /// pushes an item back on the stack
        /// </summary>
        /// <param name="obj">Object.</param>
        public static void free(List<T> obj)
        {
            _objectQueue.Enqueue(obj);
            obj.Clear();
        }
    }
}