/* * Copyright (c) Contributors, http://opensimulator.org/ * See CONTRIBUTORS.TXT for a full list of copyright holders. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * Neither the name of the OpenSimulator Project nor the * names of its contributors may be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ using System; using System.Collections.Generic; namespace OpenSim.Framework { /// <summary> /// Stores two synchronized collections: a mutable dictionary and an /// immutable array. Slower inserts/removes than a normal dictionary, /// but provides safe iteration while maintaining fast hash lookups /// </summary> /// <typeparam name="TKey">Key type to use for hash lookups</typeparam> /// <typeparam name="TValue">Value type to store</typeparam> public sealed class MapAndArray<TKey, TValue> { private Dictionary<TKey, TValue> m_dict; private TValue[] m_array; private object m_syncRoot = new object(); /// <summary>Number of values currently stored in the collection</summary> public int Count { get { return m_array.Length; } } /// <summary>NOTE: This collection is thread safe. You do not need to /// acquire a lock to add, remove, or enumerate entries. This /// synchronization object should only be locked for larger /// transactions</summary> public object SyncRoot { get { return m_syncRoot; } } /// <summary> /// Constructor /// </summary> public MapAndArray() { m_dict = new Dictionary<TKey, TValue>(); m_array = new TValue[0]; } /// <summary> /// Constructor /// </summary> /// <param name="capacity">Initial capacity of the dictionary</param> public MapAndArray(int capacity) { m_dict = new Dictionary<TKey, TValue>(capacity); m_array = new TValue[0]; } /// <summary> /// Adds a key/value pair to the collection, or updates an existing key /// with a new value /// </summary> /// <param name="key">Key to add or update</param> /// <param name="value">Value to add</param> /// <returns>True if a new key was added, false if an existing key was /// updated</returns> public bool AddOrReplace(TKey key, TValue value) { lock (m_syncRoot) { bool containedKey = m_dict.ContainsKey(key); m_dict[key] = value; CreateArray(); return !containedKey; } } /// <summary> /// Adds a key/value pair to the collection. This will throw an /// exception if the key is already present in the collection /// </summary> /// <param name="key">Key to add or update</param> /// <param name="value">Value to add</param> /// <returns>Index of the inserted item</returns> public int Add(TKey key, TValue value) { lock (m_syncRoot) { m_dict.Add(key, value); CreateArray(); return m_array.Length; } } /// <summary> /// Removes a key/value pair from the collection /// </summary> /// <param name="key">Key to remove</param> /// <returns>True if the key was found and removed, otherwise false</returns> public bool Remove(TKey key) { lock (m_syncRoot) { bool removed = m_dict.Remove(key); CreateArray(); return removed; } } /// <summary> /// Determines whether the collections contains a specified key /// </summary> /// <param name="key">Key to search for</param> /// <returns>True if the key was found, otherwise false</returns> public bool ContainsKey(TKey key) { lock (m_syncRoot) return m_dict.ContainsKey(key); } /// <summary> /// Gets the value associated with the specified key /// </summary> /// <param name="key">Key of the value to get</param> /// <param name="value">Will contain the value associated with the /// given key if the key is found. If the key is not found it will /// contain the default value for the type of the value parameter</param> /// <returns>True if the key was found and a value was retrieved, /// otherwise false</returns> public bool TryGetValue(TKey key, out TValue value) { lock (m_syncRoot) return m_dict.TryGetValue(key, out value); } /// <summary> /// Clears all key/value pairs from the collection /// </summary> public void Clear() { lock (m_syncRoot) { m_dict = new Dictionary<TKey, TValue>(); m_array = new TValue[0]; } } /// <summary> /// Gets a reference to the immutable array of values stored in this /// collection. This array is thread safe for iteration /// </summary> /// <returns>A thread safe reference ton an array of all of the stored /// values</returns> public TValue[] GetArray() { return m_array; } private void CreateArray() { // Rebuild the array from the dictionary. This method must be // called from inside a lock TValue[] array = new TValue[m_dict.Count]; int i = 0; foreach (TValue value in m_dict.Values) array[i++] = value; m_array = array; } } }