mirror of
https://github.com/Alex-Rachel/TEngine.git
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276 lines
9.6 KiB
C#
276 lines
9.6 KiB
C#
using System;
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using System.Collections.Generic;
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using System.Diagnostics;
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using Debug = UnityEngine.Debug;
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namespace TEngine
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{
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/// <summary>
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/// Adaptive Replacement Cache缓存表。
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/// </summary>
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/// <typeparam name="TKey">Adaptive Replacement CacheKey。</typeparam>
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/// <typeparam name="TValue">Adaptive Replacement CacheValue</typeparam>
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/// <remarks>缓存替换策略（Cache Replacement Policy）- ARC（Adaptive Replacement Cache）。</remarks>
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public class ArcCacheTable<TKey, TValue>
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{
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/// <summary>
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/// ARC缓存表哈希表。
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/// <remarks>Dictionary 中存储 key 和 QueueNode 中节点的映射关系。</remarks>
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/// <remarks>算法优化的关键在于如何降低链表的删除操作的时间复杂度。不管是在插入、删除、查找缓存的时候，都可以通过这种联系来将时间复杂度降低到 O(1)。</remarks>
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/// </summary>
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protected readonly Dictionary<TKey, QueueNode<TKey, TValue>> CacheStorageMap;
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private readonly QueueNode<TKey, TValue> _t1Head;
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private readonly QueueNode<TKey, TValue> _t2Head;
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private readonly QueueNode<TKey, TValue> _b1Head;
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private readonly QueueNode<TKey, TValue> _b2Head;
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private int _adaptiveParameter;
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private int _t1Size;
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private int _t2Size;
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private int _b1Size;
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private int _b2Size;
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protected readonly int Capacity;
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public delegate void OnAdd(TKey key,TValue data);
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public delegate void OnRemove(TKey key,TValue data);
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/// <summary>
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/// ARC缓存表添加成功回调。
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/// </summary>
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public readonly OnAdd OnAddCallback;
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/// <summary>
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/// ARC缓存表移除回调。
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/// </summary>
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public readonly OnRemove OnRemoveCallback;
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/// <summary>
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/// ARC缓存表哈希表构造。
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/// </summary>
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/// <param name="capacity">容量。</param>
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/// <param name="onAdd">LRU缓存表添加成功回调。</param>
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/// <param name="onRemove">LRU缓存表移除回调。</param>
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public ArcCacheTable(int capacity, OnAdd onAdd = null, OnRemove onRemove = null)
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{
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Capacity = capacity;
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OnAddCallback = onAdd;
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OnRemoveCallback = onRemove;
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CacheStorageMap = new Dictionary<TKey, QueueNode<TKey, TValue>>();
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_t1Head = new QueueNode<TKey, TValue>();
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_t2Head = new QueueNode<TKey, TValue>();
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_b1Head = new QueueNode<TKey, TValue>();
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_b2Head = new QueueNode<TKey, TValue>();
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}
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/// <summary>
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/// 对象推入ARC缓存表。
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/// </summary>
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/// <param name="key">键。</param>
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/// <param name="value">值。</param>
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public void PutCache(TKey key, TValue value)
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{
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CacheStorageMap.TryGetValue(key, out QueueNode<TKey, TValue> queueNode);
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if (queueNode == null)
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{
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OnMissOnAllQueue(key, value);
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OnAddCallback?.Invoke(key,value);
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}
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else if (queueNode.QueueType == QueueType.B1)
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{
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queueNode.Set(value);
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OnHitOnB1(queueNode);
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}
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else if (queueNode.QueueType == QueueType.B2)
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{
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queueNode.Set(value);
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OnHitOnB2(queueNode);
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}
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else
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{
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queueNode.Set(value);
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OnHitOnT1orT2(queueNode);
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}
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}
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/// <summary>
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/// 从ARC缓存表取出对象。
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/// </summary>
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/// <param name="key">键。</param>
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/// <returns>TValue from cache if exists or null。</returns>
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public TValue GetCache(TKey key)
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{
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CacheStorageMap.TryGetValue(key, out QueueNode<TKey, TValue> queueNode);
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if (queueNode == null)
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{
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return default;
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}
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else
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{
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return queueNode.Get();
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}
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}
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/// <summary>
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/// 在所有队列中未命中时执行任务(Case：Key不在(T1 u B1 u T2 u B2))。
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/// </summary>
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/// <param name="key">key cache key。</param>
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/// <param name="value">value to inset in cache。</param>
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private void OnMissOnAllQueue(TKey key, TValue value)
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{
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QueueNode<TKey, TValue> queueNode = new QueueNode<TKey, TValue>(key, value);
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queueNode.QueueType = QueueType.T1;
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int sizeL1 = _t1Size + _b1Size;
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int sizeL2 = _t2Size + _b2Size;
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if (sizeL1 == Capacity)
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{
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if (_t1Size < Capacity)
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{
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QueueNode<TKey, TValue> queueNodeToBeRemoved = _b1Head.Next;
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RemoveFromQueue(queueNodeToBeRemoved);
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queueNodeToBeRemoved.Remove();
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_b1Size--;
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Replace(queueNode);
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}
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else
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{
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QueueNode<TKey, TValue> queueNodeToBeRemoved = _t1Head.Next;
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RemoveFromQueue(queueNodeToBeRemoved);
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queueNodeToBeRemoved.Remove();
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_t1Size--;
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}
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}
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else if (sizeL1 < Capacity && sizeL1 + sizeL2 >= Capacity)
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{
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if (sizeL1 + sizeL2 >= 2 * Capacity)
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{
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QueueNode<TKey, TValue> queueNodeToBeRemoved = _b2Head.Next;
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RemoveFromQueue(queueNodeToBeRemoved);
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queueNodeToBeRemoved.Remove();
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_b2Size--;
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}
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Replace(queueNode);
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}
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_t1Size++;
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CacheStorageMap.Add(key, queueNode);
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queueNode.AddToLast(_t1Head);
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}
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/// <summary>
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/// 执行任务命中B1 (Case：Key在B1中)。
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/// </summary>
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/// <param name="queueNode">queueNode queue node。</param>
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private void OnHitOnB1(QueueNode<TKey, TValue> queueNode)
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{
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_adaptiveParameter = Math.Min(Capacity, _adaptiveParameter + Math.Max(_b2Size / _b1Size, 1));
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Replace(queueNode);
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_t2Size++;
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_b1Size--;
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queueNode.Remove();
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queueNode.QueueType = QueueType.T2;
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queueNode.AddToLast(_t2Head);
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}
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/// <summary>
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/// 执行任务命中B2 (Case：Key在B2中)。
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/// </summary>
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/// <param name="queueNode">queueNode queue node。</param>
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private void OnHitOnB2(QueueNode<TKey, TValue> queueNode)
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{
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_adaptiveParameter = Math.Max(0, _adaptiveParameter - Math.Max(_b1Size / _b2Size, 1));
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Replace(queueNode);
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_t2Size++;
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_b2Size--;
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queueNode.Remove();
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queueNode.QueueType = QueueType.T2;
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queueNode.AddToLast(_t2Head);
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}
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/// <summary>
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/// 执行任务命中T1或者T2 (Case：Key在T1或者T2中)。
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/// </summary>
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/// <param name="queueNode">queueNode queue node。</param>
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private void OnHitOnT1orT2(QueueNode<TKey, TValue> queueNode)
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{
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if (queueNode.QueueType == QueueType.T1)
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{
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_t1Size--;
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_t2Size++;
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}
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queueNode.Remove();
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queueNode.QueueType = QueueType.T2;
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queueNode.AddToLast(_t2Head);
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}
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/// <summary>
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/// 替换队列节点（情况：L1（T1 u B1）少于c个）
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/// </summary>
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/// <param name="queueNode">queueNode queue node。</param>
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private void Replace(QueueNode<TKey, TValue> queueNode)
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{
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if (_t1Size >= 1 && ((queueNode.QueueType == QueueType.B2 && _t1Size == _adaptiveParameter) || _t1Size > _adaptiveParameter))
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{
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QueueNode<TKey, TValue> queueNodeToBeRemoved = _t1Head.Next;
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queueNodeToBeRemoved.Remove();
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queueNodeToBeRemoved.QueueType = QueueType.B1;
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queueNodeToBeRemoved.AddToLast(_b1Head);
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_t1Size--;
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_b1Size++;
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}
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else
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{
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QueueNode<TKey, TValue> queueNodeToBeRemoved = _t2Head.Next;
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queueNodeToBeRemoved.Remove();
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queueNodeToBeRemoved.QueueType = QueueType.B2;
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queueNodeToBeRemoved.AddToLast(_b2Head);
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_t2Size--;
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_b2Size++;
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}
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}
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/// <summary>
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/// Remove TValue data from queue and dispose it
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/// </summary>
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/// <param name="queueNodeToBeRemoved">queueNodeToBeRemoved queue node to be remove from queue</param>
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public void RemoveFromQueue(QueueNode<TKey, TValue> queueNodeToBeRemoved)
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{
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CacheStorageMap.Remove(queueNodeToBeRemoved.Key);
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TValue value = queueNodeToBeRemoved.Get();
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try
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{
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OnRemoveCallback?.Invoke(queueNodeToBeRemoved.Key,value);
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}
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catch (Exception e)
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{
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Debug.Log(e);
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}
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}
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[Conditional("UNITY_EDITOR")]
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public void PrintCacheIdsFromQueue()
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{
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String keys = "";
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foreach (var queueNode in CacheStorageMap)
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{
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var key = queueNode.Key;
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if (keys == "")
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keys += key;
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else
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keys += " | " + key;
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}
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Debug.Log("All Existing Keys in Cache are : " + keys);
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}
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}
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} |