我已经尝试过调试这个，但我已经到了一个我不知道为什么会发生这种情况的地方（我也是一个线程新手）。大约有2/3的出列数据显示为null，而其余数据则正常。任何见解将不胜感激。
using UnityEngine;
using System;
using System.Net;
using System.Net.Sockets;
using System.Threading;
namespace UDPNetwork
{
public class NetworkManager : MonoBehaviour
{
struct DataPacket
{
public IPEndPoint destination;
public byte[] data;
public int size;
public DataPacket(IPEndPoint destination, byte[] data)
{
this.destination = destination;
this.data = data;
size = 0;
}
}
[SerializeField]
string SERVER_IP = "127.0.0.1";
[SerializeField]
ushort SERVER_PORT = 55566;
AsyncPriorityQueue<DataPacket> queuedReceiveData = new AsyncPriorityQueue<DataPacket>(2000, false);
Socket sck;
IPEndPoint ipEndPoint;
bool listening = true;
bool processing = true;
void Start()
{
sck = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
#if SERVER
ipEndPoint = new IPEndPoint(IPAddress.Any, SERVER_PORT);
sck.Bind(ipEndPoint);
#endif
new Thread(() => ListenForData()).Start();
new Thread(() => ProcessData()).Start();
}
void OnDestroy()
{
listening = false;
processing = false;
sck.Close();
}
void ListenForData()
{
EndPoint endPoint = ipEndPoint;
while (listening)
{
byte[] buffer = new byte[512];
try
{
int rec = sck.ReceiveFrom(buffer, 0, buffer.Length, SocketFlags.None, ref endPoint);
Array.Resize(ref buffer, rec);
queuedReceiveData.Enqueue(new DataPacket((IPEndPoint)endPoint, buffer) { size = rec }, 0);
}
catch (Exception e)
{
Debug.LogError(e.Message);
}
}
}
void ProcessData()
{
DataPacket rcv;
byte[] data;
IPEndPoint ep;
while (processing)
{
rcv = queuedReceiveData.Dequeue(); // blocks until queue has >1 item
data = rcv.data;
ep = rcv.destination;
if (data == null)
{
Debug.LogError(data); // null
Debug.LogError(rcv.size); // 0
Debug.LogError(ep); // null
Debug.LogError(rcv);
continue;
}
//process...
}
}
}
}
队列：
using System;
/// <summary>
/// Priority queue removes added items highest priority items first, ties broken by First-In-First-Out.
/// </summary>
/// <typeparam name="T"></typeparam>
public class PriorityQueue<T>
{
struct Node
{
public T item;
public int priority;
public CircularInt32 insertionIndex;
}
Node[] items;
bool _resizeable;
CircularInt32 _numItemsEverEnqueued = 0;
/// <summary>
/// How many items are currently in the queue
/// </summary>
public int Count
{
get;
private set;
}
/// <summary>
/// How many items the queue can hold. 0 == infinite.
/// </summary>
public int Capacity
{
get
{
return _resizeable ? 0 : items.Length;
}
}
/// <summary>
/// Create a new resizeable priority queue with default capacity (8)
/// </summary>
public PriorityQueue() : this(8) { }
/// <summary>
/// Create a new priority queue
/// </summary>
/// <param name="capacity"></param>
/// <param name="resizeable"></param>
public PriorityQueue(int capacity, bool resizeable = true)
{
if (capacity < 2)
{
throw new ArgumentException("New queue size cannot be smaller than 2", "capacity");
}
items = new Node[capacity];
Count = 0;
_resizeable = resizeable;
}
/// <summary>
/// Add an object to the queue. If queue is full and resizeable is true, increases the capacity. If queue is full and resizeable is false, does nothing, returns false.
/// </summary>
/// <param name="item">object to add to queue</param>
/// <param name="priority">object's priority, lower # = higher priority, ties are broken by FIFO</param>
/// <returns>true if added successfully, false otherwise (queue is full)</returns>
public bool Enqueue(T item, int priority)
{
if (Count == items.Length)
{
if (_resizeable)
{
Array.Resize(ref items, Capacity * 3 / 2 + 1);
}
else
{
return false;
}
}
items[Count] = new Node() { item = item, priority = priority, insertionIndex = _numItemsEverEnqueued++ };
percolateUp(Count);
Count++;
return true;
}
void percolateUp(int index)
{
while (true)
{
if (index == 0)
{
break;
}
int parent = (index % 2 == 0) ? index / 2 - 1 : index / 2;
if (HasHigherPriority(items[parent], items[index]))
{
var temp = items[index];
items[index] = items[parent];
items[parent] = temp;
index = parent;
}
else
{
break;
}
}
}
/// <summary>
/// Removes and returns the highest priority object in the queue. Ties are broken by FIFO.
/// Returns an object's default value if the queue is empty.
/// </summary>
/// <returns></returns>
public T Dequeue()
{
if (Count == 0)
{
return default(T);
}
var item = items[0].item;
items[0] = new Node();
percolateDown(0);
Count--;
return item;
}
void percolateDown(int index)
{
while (true)
{
int left = index * 2 + 1;
if (left + 1 < Count && HasHigherPriority(items[left + 1], items[left]))
{
var temp = items[index];
items[index] = items[left + 1];
items[left + 1] = temp;
index = left + 1;
}
else if (left < Count)
{
var temp = items[index];
items[index] = items[left];
items[left] = temp;
index = left;
}
else
{
break;
}
}
}
bool HasHigherPriority(Node higher, Node lower)
{
return (higher.priority < lower.priority || (higher.priority == lower.priority && higher.insertionIndex < lower.insertionIndex));
}
}
异步：
using System.Threading;
/// <summary>
/// A thread-safe priority queue.
/// </summary>
/// <typeparam name="T"></typeparam>
public class AsyncPriorityQueue<T>
{
PriorityQueue<T> pq;
/// <summary>
/// How many items are currently in the queue
/// </summary>
public int Count
{
get { return pq.Count; }
}
/// <summary>
/// How many items the queue can hold. 0 == infinite.
/// </summary>
public int Capacity
{
get { return pq.Capacity; }
}
/// <summary>
/// Create a new resizeable async priority queue with default capacity (8)
/// </summary>
public AsyncPriorityQueue()
{
pq = new PriorityQueue<T>();
}
/// <summary>
/// Create a new priority queue
/// </summary>
/// <param name="capacity"></param>
/// <param name="resizeable"></param>
public AsyncPriorityQueue(int capacity, bool resizeable = true)
{
pq = new PriorityQueue<T>(capacity, resizeable);
}
/// <summary>
/// Add an object to the queue. If queue is full and resizeable is true, increases the capacity. If queue is full and resizeable is false, does nothing, returns false.
/// </summary>
/// <param name="item">object to add to queue</param>
/// <param name="priority">object's priority, lower # = higher priority, ties are broken by FIFO</param>
/// <returns>true if added successfully, false otherwise (queue is full)</returns>
public bool Enqueue(T item, int priority)
{
lock (pq)
{
bool added = pq.Enqueue(item, priority);
if (pq.Count == 1)
{
Monitor.Pulse(pq);
}
return added;
}
}
/// <summary>
/// Removes and returns the highest priority object in the queue. Ties are broken by FIFO.
/// WARNING: if the queue is empty when this is called, the thread WILL BLOCK until a new item is added to the queue in another thread. If this behaviour is not wanted, be sure to check Count > 0.
/// </summary>
/// <returns></returns>
public T Dequeue()
{
lock (pq)
{
while (pq.Count == 0)
{
Monitor.Wait(pq);
}
return pq.Dequeue();
}
}
}
答案 0 :(得分：0)
首先，当您的所有邮件以优先级0排队时，不清楚为什么要使用优先级队列。但我会假设您的目标是最终更改优先级一些消息。在任何情况下，因为您将所有内容排入优先级0，所以您在优先级队列实现中揭露了一个关键错误。
我怀疑如果你将优先级为1的所有内容排入队列，你就永远不会看到这个错误。但你不应该这样做。
问题在于，当您使项目出列时，您可以通过渗透优先级为0的空节点来重新调整堆。更重要的是，它的insertionIndex永远不会被设置，所以它最终将新的空节点放在已经在队列中的好节点之前，稍后添加到队列的新节点将被添加到之后那个空节点。并且因为队列中的所有内容都是优先级0，所以新的空节点就在根处。
您需要更改在项目出列时重新调整堆的方式。您应该取出堆中的最后一个节点，将其插入根目录并将其渗透下来，而不是在顶部输入一个空节点并将其向下渗透。但是您必须更改percolateDown方法。
以下是我的建议：
public T Dequeue()
{
if (Count == 0)
{
return default(T);
}
var item = items[0].item;
items[0] = items[Count-1];
items[Count-1] = null;
Count--;
percolateDown(0);
return item;
}
void percolateDown(int index)
{
while (true)
{
// The rules for adjusting on percolate down are to swap the
// node with the highest-priority child. So first we have to
// find the highest-priority child.
int hpChild = index*2+1;
if (hpChild >= Count)
{
break;
}
if (hpChild+1 < Count && HasHigherPriority(items[hpChild+1], items[hpChild]))
{
++hpChild;
}
if (HasHigherPriority(items[hpChild, items[index]))
{
var temp = items[index];
items[index] = items[hpChild];
items[hpChild] = temp;
}
else
{
break;
}
index = hpChild;
}
}
有关正确实现二进制堆的更多详细信息，请参阅http://blog.mischel.com/2013/09/29/a-better-way-to-do-it-the-heap/以及后续条目。
其他几点说明：
您应该将items数组转换为List<Node>，而不是自己调整数组大小。它将处理所有调整大小等等。
在percolateUp，您有：
int parent = (index % 2 == 0) ? index / 2 - 1 : index / 2;
您可以将其简化为：
int parent = (index + 1)/2;