public virtual IEnumerable<object> Unpack(Zongsoft.Common.Buffer buffer)
{
int availableLength;
while(buffer.CanRead())
{
//如果当前头部缓存指针位置小于包头的长度，则必须先读取头部数据
if(_contentLength == 0 && _headOffset < HEAD_LENGTH)
{
//从当前接受缓存中读取剩下的包头数据
availableLength = buffer.Read(_headBuffer, _headOffset, HEAD_LENGTH - _headOffset);
//将当前头部缓存指针加上当前实际读取的长度
_headOffset += availableLength;
//如果当前头部缓存指针位置仍然小于包头长度，则说明当前接数据缓存区数据量不够，
//即本次接收到的缓存数据已被读完，故直接退出当前方法。
if(_headOffset < HEAD_LENGTH)
yield break;
//至此头部数据接收完毕，将头部缓存解析成包头实体
_head = this.ResolveHeader(_headBuffer);
//如果包头指示当前数据包的实际内容长度为零，则说明此包为空包
if(_head.TotalLength == 0 || _head.ContentLength == 0)
{
//重置缓存指针位置，以指示下次需要进行包头解析
_headOffset = 0;
_contentLength = 0;
//接着处理下一个小包
continue;
}
//映射当前数据包对应的缓存区。
if(!_bufferStates.ContainsKey(_head.SequenceId))
{
var bufferManager = this.GetBufferManager();
var id = bufferManager.Allocate(_head.TotalLength);
_bufferStates[_head.SequenceId] = new BufferState(bufferManager.GetStream(id));
}
}
//计算出本次要接受的内容长度
int contentLength = _contentLength == 0 ? _head.ContentLength : _contentLength;
//定义当前接收的数据包对应的缓存状态对象
BufferState bufferState;
//从缓存容器中获取当前大包的缓存状态对象
if(!_bufferStates.TryGetValue(_head.SequenceId, out bufferState))
throw new InvalidOperationException("Can not obtain the BufferCache with sequence-id.");
//将接收到的数据写入缓存区
availableLength = buffer.Read(bufferState.BufferStream, contentLength);
//更新当前缓存状态中的缓存数
bufferState.BufferedSize += availableLength;
//设置下次要接收的内容长度
_contentLength = contentLength - availableLength;
//如果下次要接收的内容长度为零，则指示下次接收要先进行包头的处理，即将头缓存偏移量置零
if(_contentLength == 0)
_headOffset = 0;
//如果整个大包全部接受完毕
if(bufferState.BufferedSize == _head.TotalLength)
{
//重置缓存指针位置，以指示下次需要进行包头解析
_headOffset = 0;
_contentLength = 0;
//重置当前缓存区流的指针
bufferState.BufferStream.Position = 0;
//将当前接收的数据包从缓存映射中删除
_bufferStates.Remove(_head.SequenceId);
yield return bufferState.BufferStream;
}
}
}
public virtual IEnumerable<Zongsoft.Common.Buffer> Pack(Zongsoft.Common.Buffer buffer)
{
if(buffer == null || buffer.Count == 0)
{
//遍历返回字节组缓存信息
yield return new Zongsoft.Common.Buffer(new byte[HEAD_LENGTH], 0);
}
var sequenceId = System.Threading.Interlocked.Increment(ref _sequenceId);
var bytes = new byte[_bufferEvaluator.GetBufferSize(buffer.Count)];
int contentLength = 0;
while((contentLength = buffer.Read(bytes, HEAD_LENGTH, bytes.Length - HEAD_LENGTH)) > 0)
{
//设置包的头部字段
this.SetPackageHead(bytes, sequenceId, buffer.Count, contentLength);
//遍历返回字节组缓存信息
yield return new Zongsoft.Common.Buffer(bytes, 0, HEAD_LENGTH + contentLength);
//注意：一定要重新分配缓存数组，不然同一个缓存在高速发送过程中肯定会发生写入覆盖
bytes = new byte[_bufferEvaluator.GetBufferSize(buffer.Count)];
}
}
