/*
Module : SNTP.H
Purpose: Interface for a MFC class to encapsulate the SNTP protocol
Created: PJN / 05-08-1998
History: PJN / None


Copyright (c) 1998 by PJ Naughter.  
All rights reserved.


*/

#ifndef __SNTP_H__
#define __SNTP_H__



///////////////////////////////// Classes //////////////////////////////

//Representation of an NTP timestamp
struct CNtpTimePacket
{
  DWORD m_dwInteger;
	DWORD m_dwFractional;
};

//Helper class to encapulate NTP time stamps
class CNtpTime
{
public:
//Constructors / Destructors
  CNtpTime();
  CNtpTime(const CNtpTime& time);
  CNtpTime(CNtpTimePacket& packet);
  CNtpTime(const SYSTEMTIME& st);

//General functions
  CNtpTime& operator=(const CNtpTime& time);
	double operator-(const CNtpTime& time) const;
	CNtpTime operator+(const double& timespan) const;
  operator SYSTEMTIME() const;
  operator CNtpTimePacket() const;
  operator unsigned __int64() const { return m_Time; };
  DWORD Seconds() const;
  DWORD Fraction() const;

//Static functions
  static CNtpTime GetCurrentTime();
  static DWORD MsToNtpFraction(WORD wMilliSeconds);
  static WORD NtpFractionToMs(DWORD dwFraction);
	static double NtpFractionToSecond(DWORD dwFraction);

protected:
//Internal static functions and data
  static long GetJulianDay(WORD Year, WORD Month, WORD Day);
  static void GetGregorianDate(long JD, WORD& Year, WORD& Month, WORD& Day);
  static DWORD m_MsToNTP[1000];

//The actual data
  unsigned __int64 m_Time;
};

struct NtpServerResponse
{
  int m_nLeapIndicator; //0: no warning
                        //1: last minute in day has 61 seconds
                        //2: last minute has 59 seconds
                        //3: clock not synchronized

  int m_nStratum; //0: unspecified or unavailable
                  //1: primary reference (e.g., radio clock)
                  //2-15: secondary reference (via NTP or SNTP)
                  //16-255: reserved

  CNtpTime     m_OriginateTime;    //Time when the request was sent from the client to the SNTP server
  CNtpTime     m_ReceiveTime;      //Time when the request was received by the server
  CNtpTime     m_TransmitTime;     //Time when the server sent the request back to the client
  CNtpTime     m_DestinationTime;  //Time when the reply was received by the client
  double       m_RoundTripDelay;   //Round trip time in seconds
  double       m_LocalClockOffset; //Local clock offset relative to the server
};
                  
//The actual SNTP class
class CSNTPClient
{
public:
//Constructors / Destructors
  CSNTPClient();

//General functions
  BOOL  GetServerTime(LPCTSTR pszHostName, NtpServerResponse& response, int nPort = 123);
  DWORD GetTimeout() const { return m_dwTimeout; };
  void  SetTimeout(DWORD dwTimeout) { m_dwTimeout = dwTimeout; };
  BOOL  SetClientTime(const CNtpTime& NewTime);

protected:
  BOOL EnableSetTimePriviledge();
  void RevertSetTimePriviledge();

  DWORD            m_dwTimeout;
  HANDLE           m_hToken;
  TOKEN_PRIVILEGES m_TokenPriv;
  BOOL             m_bTakenPriviledge;
};

#endif //__SNTP_H__