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*****************************************************************************/

/*****************************************************************************
written by
   Yunhong Gu, last updated 02/28/2012
*****************************************************************************/


#ifndef __UDT_CCC_H__
#define __UDT_CCC_H__


#include "udt.h"
#include "packet.h"


class UDT_API CCC
{
friend class CUDT;

public:
   CCC();
   virtual ~CCC();

private:
   CCC(const CCC&);
   CCC& operator=(const CCC&) {return *this;}

public:

      /// Callback function to be called (only) at the start of a UDT connection.
      /// note that this is different from CCC(), which is always called.

   virtual void init() {}

      /// Callback function to be called when a UDT connection is closed.

   virtual void close() {}

      /// Callback function to be called when an ACK packet is received.
      /// @param [in] ackno the data sequence number acknowledged by this ACK.

   virtual void onACK(int32_t) {}

      /// Callback function to be called when a loss report is received.
      /// @param [in] losslist list of sequence number of packets, in the format describled in packet.cpp.
      /// @param [in] size length of the loss list.

   virtual void onLoss(const int32_t*, int) {}

      /// Callback function to be called when a timeout event occurs.

   virtual void onTimeout() {}

      /// Callback function to be called when a data is sent.
      /// @param [in] seqno the data sequence number.
      /// @param [in] size the payload size.

   virtual void onPktSent(const CPacket*) {}

      /// Callback function to be called when a data is received.
      /// @param [in] seqno the data sequence number.
      /// @param [in] size the payload size.

   virtual void onPktReceived(const CPacket*) {}

      /// Callback function to Process a user defined packet.
      /// @param [in] pkt the user defined packet.

   virtual void processCustomMsg(const CPacket*) {}

protected:

      /// Set periodical acknowldging and the ACK period.
      /// @param [in] msINT the period to send an ACK.

   void setACKTimer(int msINT);

      /// Set packet-based acknowldging and the number of packets to send an ACK.
      /// @param [in] pktINT the number of packets to send an ACK.

   void setACKInterval(int pktINT);

      /// Set RTO value.
      /// @param [in] msRTO RTO in macroseconds.

   void setRTO(int usRTO);

      /// Send a user defined control packet.
      /// @param [in] pkt user defined packet.

   void sendCustomMsg(CPacket& pkt) const;

      /// retrieve performance information.
      /// @return Pointer to a performance info structure.

   const CPerfMon* getPerfInfo();

      /// Set user defined parameters.
      /// @param [in] param the paramters in one buffer.
      /// @param [in] size the size of the buffer.

   void setUserParam(const char* param, int size);

private:
   void setMSS(int mss);
   void setMaxCWndSize(int cwnd);
   void setBandwidth(int bw);
   void setSndCurrSeqNo(int32_t seqno);
   void setRcvRate(int rcvrate);
   void setRTT(int rtt);

protected:
   const int32_t& m_iSYNInterval;	// UDT constant parameter, SYN

   double m_dPktSndPeriod;              // Packet sending period, in microseconds
   double m_dCWndSize;                  // Congestion window size, in packets

   int m_iBandwidth;			// estimated bandwidth, packets per second
   double m_dMaxCWndSize;               // maximum cwnd size, in packets

   int m_iMSS;				// Maximum Packet Size, including all packet headers
   int32_t m_iSndCurrSeqNo;		// current maximum seq no sent out
   int m_iRcvRate;			// packet arrive rate at receiver side, packets per second
   int m_iRTT;				// current estimated RTT, microsecond

   char* m_pcParam;			// user defined parameter
   int m_iPSize;			// size of m_pcParam

private:
   UDTSOCKET m_UDT;                     // The UDT entity that this congestion control algorithm is bound to

   int m_iACKPeriod;                    // Periodical timer to send an ACK, in milliseconds
   int m_iACKInterval;                  // How many packets to send one ACK, in packets

   bool m_bUserDefinedRTO;              // if the RTO value is defined by users
   int m_iRTO;                          // RTO value, microseconds

   CPerfMon m_PerfInfo;                 // protocol statistics information
};

class CCCVirtualFactory
{
public:
   virtual ~CCCVirtualFactory() {}

   virtual CCC* create() = 0;
   virtual CCCVirtualFactory* clone() = 0;
};

template <class T>
class CCCFactory: public CCCVirtualFactory
{
public:
   virtual ~CCCFactory() {}

   virtual CCC* create() {return new T;}
   virtual CCCVirtualFactory* clone() {return new CCCFactory<T>;}
};

class CUDTCC: public CCC
{
public:
   CUDTCC();

public:
   virtual void init();
   virtual void onACK(int32_t);
   virtual void onLoss(const int32_t*, int);
   virtual void onTimeout();

private:
   int m_iRCInterval;			// UDT Rate control interval
   uint64_t m_LastRCTime;		// last rate increase time
   bool m_bSlowStart;			// if in slow start phase
   int32_t m_iLastAck;			// last ACKed seq no
   bool m_bLoss;			// if loss happened since last rate increase
   int32_t m_iLastDecSeq;		// max pkt seq no sent out when last decrease happened
   double m_dLastDecPeriod;		// value of pktsndperiod when last decrease happened
   int m_iNAKCount;                     // NAK counter
   int m_iDecRandom;                    // random threshold on decrease by number of loss events
   int m_iAvgNAKNum;                    // average number of NAKs per congestion
   int m_iDecCount;			// number of decreases in a congestion epoch
};

#endif