/*************************************************************************\
* Copyright (c) 2009 UChicago Argonne LLC, as Operator of Argonne
*     National Laboratory.
* Copyright (c) 2002 The Regents of the University of California, as
*     Operator of Los Alamos National Laboratory.
* EPICS BASE is distributed subject to a Software License Agreement found
* in file LICENSE that is included with this distribution. 
\*************************************************************************/
/* epicsTime.h */
/* Author Jeffrey O. Hill */

#ifndef epicsTimehInclude
#define epicsTimehInclude

#include <time.h>

#include "shareLib.h"
#include "epicsTypes.h"
#include "osdTime.h"

/* The EPICS Epoch is 00:00:00 Jan 1, 1990 UTC */
#define POSIX_TIME_AT_EPICS_EPOCH 631152000u

/* epics time stamp for C interface*/
typedef struct epicsTimeStamp {
    epicsUInt32    secPastEpoch;   /* seconds since 0000 Jan 1, 1990 */
    epicsUInt32    nsec;           /* nanoseconds within second */
} epicsTimeStamp;

/*TS_STAMP is deprecated */
#define TS_STAMP epicsTimeStamp


struct timespec; /* POSIX real time */
struct timeval; /* BSD */
struct l_fp; /* NTP timestamp */

#ifdef __cplusplus

/*
 * extend ANSI C RTL "struct tm" to include nano seconds within a second
 * and a struct tm that is adjusted for the local timezone
 */
struct local_tm_nano_sec {
    struct tm ansi_tm; /* ANSI C time details */
    unsigned long nSec; /* nano seconds extension */
};

/*
 * extend ANSI C RTL "struct tm" to includes nano seconds within a second
 * and a struct tm that is adjusted for GMT (UTC)
 */
struct gm_tm_nano_sec {
    struct tm ansi_tm; /* ANSI C time details */
    unsigned long nSec; /* nano seconds extension */
};

/*
 * wrapping this in a struct allows conversion to and
 * from ANSI time_t but does not allow unexpected
 * conversions to occur
 */
struct time_t_wrapper {
    time_t ts;
};

class epicsShareClass epicsTimeEvent
{
public:
    epicsTimeEvent (const int &number);
    operator int () const;
private:
    int eventNumber;
};

class epicsShareClass epicsTime
{
public:
    /* exceptions */
    class unableToFetchCurrentTime {};
    class formatProblemWithStructTM {};

    epicsTime ();
    epicsTime ( const epicsTime & t );

    static epicsTime getEvent ( const epicsTimeEvent & );
    static epicsTime getCurrent ();

    /* convert to and from EPICS epicsTimeStamp format */
    operator epicsTimeStamp () const;
    epicsTime ( const epicsTimeStamp & ts );
    epicsTime & operator = ( const epicsTimeStamp & );

    /* convert to and from ANSI time_t */
    operator time_t_wrapper () const;
    epicsTime ( const time_t_wrapper & );
    epicsTime & operator = ( const time_t_wrapper & );

    /*
     * convert to and from ANSI Cs "struct tm" (with nano seconds)
     * adjusted for the local time zone
     */
    operator local_tm_nano_sec () const;
    epicsTime ( const local_tm_nano_sec & );
    epicsTime & operator = ( const local_tm_nano_sec & );

    /*
     * convert to ANSI Cs "struct tm" (with nano seconds)
     * adjusted for GM time (UTC)
     */
    operator gm_tm_nano_sec () const;

    /* convert to and from POSIX RTs "struct timespec" */
    operator struct timespec () const;
    epicsTime ( const struct timespec & );
    epicsTime & operator = ( const struct timespec & );

    /* convert to and from BSDs "struct timeval" */
    operator struct timeval () const;
    epicsTime ( const struct timeval & );
    epicsTime & operator = ( const struct timeval & );

    /* convert to and from NTP timestamp format */
    operator l_fp () const;
    epicsTime ( const l_fp & );
    epicsTime & operator = ( const l_fp & );

    /* convert to and from WIN32s FILETIME (implemented only on WIN32) */
    operator struct _FILETIME () const;
    epicsTime ( const struct _FILETIME & );
    epicsTime & operator = ( const struct _FILETIME & );

    /* arithmetic operators */
    double operator- ( const epicsTime & ) const; /* returns seconds */
    epicsTime operator+ ( const double & ) const; /* add rhs seconds */
    epicsTime operator- ( const double & ) const; /* subtract rhs seconds */
    epicsTime operator+= ( const double & ); /* add rhs seconds */
    epicsTime operator-= ( const double & ); /* subtract rhs seconds */

    /* comparison operators */
    bool operator == ( const epicsTime & ) const;
    bool operator != ( const epicsTime & ) const;
    bool operator <= ( const epicsTime & ) const;
    bool operator < ( const epicsTime & ) const;
    bool operator >= ( const epicsTime & ) const;
    bool operator > ( const epicsTime & ) const;

    /* convert current state to user-specified string */
    size_t strftime ( char * pBuff, size_t bufLength, const char * pFormat ) const;

    /* dump current state to standard out */
    void show ( unsigned interestLevel ) const;

private:
    /*
     * private because:
     * a) application does not break when EPICS epoch is changed
     * b) no assumptions about internal storage or internal precision
     * in the application
     * c) it would be easy to forget which argument is nanoseconds
     * and which argument is seconds (no help from compiler)
     */
    epicsTime ( const unsigned long secPastEpoch, const unsigned long nSec );
    void addNanoSec ( long nanoSecAdjust );

    unsigned long secPastEpoch; /* seconds since O000 Jan 1, 1990 */
    unsigned long nSec; /* nanoseconds within second */
};

extern "C" {
#endif /* __cplusplus */

/* All epicsTime routines return (-1,0) for (failure,success) */
#define epicsTimeOK 0
#define epicsTimeERROR (-1)

/*Some special values for eventNumber*/
#define epicsTimeEventCurrentTime 0
#define epicsTimeEventBestTime -1
#define epicsTimeEventDeviceTime -2

/* These are implemented in the "generalTime" framework */
epicsShareFunc int epicsShareAPI epicsTimeGetCurrent ( epicsTimeStamp * pDest );
epicsShareFunc int epicsShareAPI epicsTimeGetEvent (
    epicsTimeStamp *pDest, int eventNumber);

/* These are callable from an Interrupt Service Routine */
epicsShareFunc int epicsTimeGetCurrentInt(epicsTimeStamp *pDest);
epicsShareFunc int epicsTimeGetEventInt(epicsTimeStamp *pDest, int eventNumber);

/* convert to and from ANSI C's "time_t" */
epicsShareFunc int epicsShareAPI epicsTimeToTime_t (
    time_t * pDest, const epicsTimeStamp * pSrc );
epicsShareFunc int epicsShareAPI epicsTimeFromTime_t (
    epicsTimeStamp * pDest, time_t src );

/*convert to and from ANSI C's "struct tm" with nano seconds */
epicsShareFunc int epicsShareAPI epicsTimeToTM (
    struct tm * pDest, unsigned long * pNSecDest, const epicsTimeStamp * pSrc );
epicsShareFunc int epicsShareAPI epicsTimeToGMTM (
    struct tm * pDest, unsigned long * pNSecDest, const epicsTimeStamp * pSrc );
epicsShareFunc int epicsShareAPI epicsTimeFromTM (
    epicsTimeStamp * pDest, const struct tm * pSrc, unsigned long nSecSrc );

/* convert to and from POSIX RT's "struct timespec" */
epicsShareFunc int epicsShareAPI epicsTimeToTimespec (
    struct timespec * pDest, const epicsTimeStamp * pSrc );
epicsShareFunc int epicsShareAPI epicsTimeFromTimespec (
    epicsTimeStamp * pDest, const struct timespec * pSrc );

/* convert to and from BSD's "struct timeval" */
epicsShareFunc int epicsShareAPI epicsTimeToTimeval (
    struct timeval * pDest, const epicsTimeStamp * pSrc );
epicsShareFunc int epicsShareAPI epicsTimeFromTimeval (
    epicsTimeStamp * pDest, const struct timeval * pSrc );

/*arithmetic operations */
epicsShareFunc double epicsShareAPI epicsTimeDiffInSeconds (
    const epicsTimeStamp * pLeft, const epicsTimeStamp * pRight );/* left - right */
epicsShareFunc void epicsShareAPI epicsTimeAddSeconds (
    epicsTimeStamp * pDest, double secondsToAdd ); /* adds seconds to *pDest */

/*comparison operations: returns (0,1) if (false,true) */
epicsShareFunc int epicsShareAPI epicsTimeEqual (
    const epicsTimeStamp * pLeft, const epicsTimeStamp * pRight);
epicsShareFunc int epicsShareAPI epicsTimeNotEqual (
    const epicsTimeStamp * pLeft, const epicsTimeStamp * pRight);
epicsShareFunc int epicsShareAPI epicsTimeLessThan (
    const epicsTimeStamp * pLeft, const epicsTimeStamp * pRight); /*true if left < right */
epicsShareFunc int epicsShareAPI epicsTimeLessThanEqual (
    const epicsTimeStamp * pLeft, const epicsTimeStamp * pRight); /*true if left <= right) */
epicsShareFunc int epicsShareAPI epicsTimeGreaterThan (
    const epicsTimeStamp * pLeft, const epicsTimeStamp * pRight); /*true if left > right */
epicsShareFunc int epicsShareAPI epicsTimeGreaterThanEqual (
    const epicsTimeStamp * pLeft, const epicsTimeStamp * pRight); /*true if left >= right */

/*convert to ASCII string */
epicsShareFunc size_t epicsShareAPI epicsTimeToStrftime (
    char * pBuff, size_t bufLength, const char * pFormat, const epicsTimeStamp * pTS );

/* dump current state to standard out */
epicsShareFunc void epicsShareAPI epicsTimeShow (
    const epicsTimeStamp *, unsigned interestLevel );

/* OS dependent reentrant versions of the ANSI C interface because */
/* vxWorks gmtime_r interface does not match POSIX standards */
epicsShareFunc int epicsShareAPI epicsTime_localtime ( const time_t * clock, struct tm * result );
epicsShareFunc int epicsShareAPI epicsTime_gmtime ( const time_t * clock, struct tm * result );

#ifdef __cplusplus
}
#endif /* __cplusplus */

/* inline member functions ,*/
#ifdef __cplusplus

/* epicsTimeEvent */

inline epicsTimeEvent::epicsTimeEvent (const int &number) :
    eventNumber(number) {}

inline epicsTimeEvent::operator int () const
{
    return this->eventNumber;
}


/* epicsTime */

inline epicsTime epicsTime::operator - ( const double & rhs ) const
{
    return epicsTime::operator + ( -rhs );
}

inline epicsTime epicsTime::operator += ( const double & rhs )
{
    *this = epicsTime::operator + ( rhs );
    return *this;
}

inline epicsTime epicsTime::operator -= ( const double & rhs )
{
    *this = epicsTime::operator + ( -rhs );
    return *this;
}

inline bool epicsTime::operator == ( const epicsTime & rhs ) const
{
    if ( this->secPastEpoch == rhs.secPastEpoch && this->nSec == rhs.nSec ) {
    	return true;
    }
    return false;
}

inline bool epicsTime::operator != ( const epicsTime & rhs ) const
{
    return !epicsTime::operator == ( rhs );
}

inline bool epicsTime::operator >= ( const epicsTime & rhs ) const
{
    return ! ( *this < rhs );
}

inline bool epicsTime::operator > ( const epicsTime & rhs ) const
{
    return ! ( *this <= rhs );
}

inline epicsTime & epicsTime::operator = ( const local_tm_nano_sec & rhs )
{
    return *this = epicsTime ( rhs );
}

inline epicsTime & epicsTime::operator = ( const struct timespec & rhs )
{
    *this = epicsTime ( rhs );
    return *this;
}

inline epicsTime & epicsTime::operator = ( const epicsTimeStamp & rhs )
{
    *this = epicsTime ( rhs );
    return *this;
}

inline epicsTime & epicsTime::operator = ( const l_fp & rhs )
{
    *this = epicsTime ( rhs );
    return *this;
}

inline epicsTime & epicsTime::operator = ( const time_t_wrapper & rhs )
{
    *this = epicsTime ( rhs );
    return *this;
}
#endif /* __cplusplus */

#endif /* epicsTimehInclude */