/*****************************************************************************Copyright (c) 2001 - 2008, The Board of Trustees of the University of Illinois.All rights reserved.Redistribution and use in source and binary forms, with or withoutmodification, are permitted provided that the following conditions aremet:* Redistributions of source code must retain the above  copyright notice, this list of conditions and the  following disclaimer.* Redistributions in binary form must reproduce the  above copyright notice, this list of conditions  and the following disclaimer in the documentation  and/or other materials provided with the distribution.* Neither the name of the University of Illinois  nor the names of its contributors may be used to  endorse or promote products derived from this  software without specific prior written permission.THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "ASIS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULARPURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER ORCONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, ORPROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OFLIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDINGNEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THISSOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.*****************************************************************************//*****************************************************************************written by   Yunhong Gu, last updated 05/23/2008*****************************************************************************/#ifndef __UDT_CHANNEL_H__#define __UDT_CHANNEL_H__#include "udt.h"#include "packet.h"class CChannel{public:   CChannel();   CChannel(const int& version);   ~CChannel();      // Functionality:      //    Opne a UDP channel.      // Parameters:      //    0) [in] addr: The local address that UDP will use.      // Returned value:      //    None.   void open(const sockaddr* addr = NULL);      // Functionality:      //    Opne a UDP channel based on an existing UDP socket.      // Parameters:      //    0) [in] udpsock: UDP socket descriptor.      // Returned value:      //    None.   void open(UDPSOCKET udpsock);      // Functionality:      //    Disconnect and close the UDP entity.      // Parameters:      //    None.      // Returned value:      //    None.   void close() const;      // Functionality:      //    Get the UDP sending buffer size.      // Parameters:      //    None.      // Returned value:      //    Current UDP sending buffer size.   int getSndBufSize();      // Functionality:      //    Get the UDP receiving buffer size.      // Parameters:      //    None.      // Returned value:      //    Current UDP receiving buffer size.   int getRcvBufSize();      // Functionality:      //    Set the UDP sending buffer size.      // Parameters:      //    0) [in] size: expected UDP sending buffer size.      // Returned value:      //    None.   void setSndBufSize(const int& size);      // Functionality:      //    Set the UDP receiving buffer size.      // Parameters:      //    0) [in] size: expected UDP receiving buffer size.      // Returned value:      //    None.   void setRcvBufSize(const int& size);      // Functionality:      //    Query the socket address that the channel is using.      // Parameters:      //    0) [out] addr: pointer to store the returned socket address.      // Returned value:      //    None.   void getSockAddr(sockaddr* addr) const;      // Functionality:      //    Query the peer side socket address that the channel is connect to.      // Parameters:      //    0) [out] addr: pointer to store the returned socket address.      // Returned value:      //    None.   void getPeerAddr(sockaddr* addr) const;      // Functionality:      //    Send a packet to the given address.      // Parameters:      //    0) [in] addr: pointer to the destination address.      //    1) [in] packet: reference to a CPacket entity.      // Returned value:      //    Actual size of data sent.   int sendto(const sockaddr* addr, CPacket& packet) const;      // Functionality:      //    Receive a packet from the channel and record the source address.      // Parameters:      //    0) [in] addr: pointer to the source address.      //    1) [in] packet: reference to a CPacket entity.      // Returned value:      //    Actual size of data received.   int recvfrom(sockaddr* addr, CPacket& packet) const;private:   void setUDPSockOpt();private:   int m_iIPversion;                    // IP version   #ifndef WIN32      int m_iSocket;                    // socket descriptor   #else      SOCKET m_iSocket;   #endif   int m_iSndBufSize;                   // UDP sending buffer size   int m_iRcvBufSize;                   // UDP receiving buffer size};#endif