MapAndArray.cs

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 * 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:
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 *       notice, this list of conditions and the following disclaimer.
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 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
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 *       derived from this software without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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 */

using System;
using System.Collections.Generic;

namespace OpenSim.Framework
{
    public sealed class MapAndArray<TKey, TValue>
    {
        private Dictionary<TKey, TValue> m_dict;
        private TValue[] m_array;
        private object m_syncRoot = new object();

        public int Count { get { return m_array.Length; } }
        public object SyncRoot { get { return m_syncRoot; } }

        public MapAndArray()
        {
            m_dict = new Dictionary<TKey, TValue>();
            m_array = new TValue[0];
        }

        public MapAndArray(int capacity)
        {
            m_dict = new Dictionary<TKey, TValue>(capacity);
            m_array = new TValue[0];
        }

        public bool AddOrReplace(TKey key, TValue value)
        {
            lock (m_syncRoot)
            {
                bool containedKey = m_dict.ContainsKey(key);

                m_dict[key] = value;
                CreateArray();

                return !containedKey;
            }
        }

        public int Add(TKey key, TValue value)
        {
            lock (m_syncRoot)
            {
                m_dict.Add(key, value);
                CreateArray();
                return m_array.Length;
            }
        }

        public bool Remove(TKey key)
        {
            lock (m_syncRoot)
            {
                bool removed = m_dict.Remove(key);
                CreateArray();

                return removed;
            }
        }

        public bool ContainsKey(TKey key)
        {
            lock (m_syncRoot)
                return m_dict.ContainsKey(key);
        }

        public bool TryGetValue(TKey key, out TValue value)
        {
            lock (m_syncRoot)
                return m_dict.TryGetValue(key, out value);
        }

        public void Clear()
        {
            lock (m_syncRoot)
            {
                m_dict = new Dictionary<TKey, TValue>();
                m_array = new TValue[0];
            }
        }

        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;
        }
    }
}