74 lines
2.8 KiB
C#
74 lines
2.8 KiB
C#
/*
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* Copyright (c) Contributors, http://opensimulator.org/
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* See CONTRIBUTORS.TXT for a full list of copyright holders.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* * Neither the name of the OpenSimulator Project nor the
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* names of its contributors may be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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using System;
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using System.Collections.Generic;
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namespace OpenSim.Region.ClientStack.LindenUDP
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{
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/// <summary>
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/// A circular buffer and hashset for tracking incoming packet sequence
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/// numbers
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/// </summary>
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public sealed class IncomingPacketHistoryCollection
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{
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private readonly uint[] m_items;
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private HashSet<uint> m_hashSet;
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private int m_first;
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private int m_next;
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private int m_capacity;
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public IncomingPacketHistoryCollection(int capacity)
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{
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this.m_capacity = capacity;
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m_items = new uint[capacity];
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m_hashSet = new HashSet<uint>();
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}
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public bool TryEnqueue(uint ack)
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{
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lock (m_hashSet)
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{
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if (m_hashSet.Add(ack))
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{
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m_items[m_next] = ack;
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m_next = (m_next + 1) % m_capacity;
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if (m_next == m_first)
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{
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m_hashSet.Remove(m_items[m_first]);
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m_first = (m_first + 1) % m_capacity;
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}
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return true;
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}
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}
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return false;
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}
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}
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}
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