sackwindow.cs

破解的飞信源代码

namespace NCindy.Protocol.RUDP.SACK
{
    using System;
    using System.Collections.Generic;
    using System.Diagnostics;
    using System.Runtime.InteropServices;
    using System.Threading;

    internal sealed class SACKWindow
    {
        private int _acksCount;
        private List<SACKSlot> _slots = new List<SACKSlot>();

        internal SACKWindow()
        {
            SACKSlot slot = new SACKSlot(-1, -1);
            slot.ACKsCount = 0;
            this._slots.Add(slot);
        }

        [Conditional("CHECK_SACKSCOUNT")]
        private void CheckACKCount()
        {
            int num = 0;
            for (int i = 0; i < this._slots.get_Count(); i++)
            {
                num += this._slots.get_Item(i).ACKsCount;
            }
            if (num != this._acksCount)
            {
                Console.WriteLine("");
            }
        }

        internal void GetSLACKSlots(out SACKSlot slot1, out SACKSlot slot2, out SACKSlot slot3, out SACKSlot slot4)
        {
            slot1 = null;
            slot2 = null;
            slot3 = null;
            slot4 = null;
            lock (this)
            {
                if (this._slots.get_Item(0).StartPacketId >= 0)
                {
                    slot1 = this._slots.get_Item(0).Clone();
                    this._slots.get_Item(0).ACKsCount = 0;
                    Interlocked.Exchange(ref this._acksCount, this._acksCount - slot1.ACKsCount);
                    for (int i = 1; i < this._slots.get_Count(); i++)
                    {
                        SACKSlot slot = this._slots.get_Item(i);
                        if (slot.ACKsCount > 0)
                        {
                            Interlocked.Exchange(ref this._acksCount, this._acksCount - slot.ACKsCount);
                            slot.ACKsCount = 0;
                            if (slot2 == null)
                            {
                                slot2 = slot.Clone();
                            }
                            else if (slot3 == null)
                            {
                                slot3 = slot.Clone();
                            }
                            else if (slot4 == null)
                            {
                                slot4 = slot.Clone();
                                break;
                            }
                        }
                    }
                }
            }
        }

        internal void OnReceivePacket(int packetId)
        {
            Monitor.Enter(this);
            try
            {
                SACKSlot slot2;
                for (int i = 0; i < this._slots.get_Count(); i++)
                {
                    SACKSlot slot = this._slots.get_Item(i);
                    if ((packetId >= slot.StartPacketId) && (packetId <= slot.EndPacketId))
                    {
                        slot.ACKsCount++;
                        return;
                    }
                    if ((slot.EndPacketId + 1) == packetId)
                    {
                        slot.EndPacketId++;
                        slot.ACKsCount++;
                        if (slot.StartPacketId < 0)
                        {
                            slot.StartPacketId = 0;
                        }
                        if (((i + 1) < this._slots.get_Count()) && ((slot.EndPacketId + 1) == this._slots.get_Item(i + 1).StartPacketId))
                        {
                            i++;
                            slot.EndPacketId = this._slots.get_Item(i).EndPacketId;
                            slot.ACKsCount += this._slots.get_Item(i).ACKsCount;
                            this._slots.RemoveAt(i);
                        }
                        return;
                    }
                    if (packetId < slot.StartPacketId)
                    {
                        if (packetId == (slot.StartPacketId - 1))
                        {
                            slot.StartPacketId--;
                            slot.ACKsCount++;
                        }
                        else
                        {
                            slot2 = new SACKSlot(packetId, packetId);
                            this._slots.Insert(i, slot2);
                        }
                        return;
                    }
                }
                slot2 = new SACKSlot(packetId, packetId);
                this._slots.Add(slot2);
            }
            finally
            {
                Interlocked.Increment(ref this._acksCount);
                Monitor.Exit(this);
            }
        }

        internal List<SACKSlot> PrepareACKList()
        {
            List<SACKSlot> list = new List<SACKSlot>();
            lock (this)
            {
                for (int i = 1; i < this._slots.get_Count(); i++)
                {
                    SACKSlot slot = this._slots.get_Item(i);
                    if (slot.ACKsCount > 0)
                    {
                        slot.ACKsCount = 0;
                        list.Add(slot.Clone());
                    }
                }
                if ((this._slots.get_Item(0).StartPacketId > -1) && ((list.get_Count() > 1) || (this._slots.get_Item(0).ACKsCount > 0)))
                {
                    this._slots.get_Item(0).ACKsCount = 0;
                    list.Insert(0, this._slots.get_Item(0).Clone());
                }
                Interlocked.Exchange(ref this._acksCount, 0);
            }
            return list;
        }

        internal int ACKCount
        {
            get
            {
                return this._acksCount;
            }
        }
    }
}