Re: Regression fails on Alpha True64 V5.0 for

Am 11:38 19.11.01 -0500 schrieb Tom Lane:
> > Hmm.  The "memcpy" at that line is intended specifically to get around
> > any possible misaligned-pointer problem.  I have a nasty feeling that
> > Compaq's compiler is misoptimizing the memcpy into a
> > load-and-store-double kind of instruction sequence.

I wouldn't be surprised. Memcpy et al. are being inlined at even O-level 1.
The optimizer might notice a data size of 8 and reduce the code to a single
load/store operation. However, this is usually only a performance problem.
You get an alignment exception and the exception handler corrects the
fetches/writes the missing part ( besides writing the address to stdout).

BTW. : The Linux version of the Compaq Compiler is available for download
from http://www.unix.digital.com/linux/compaq_c/index.html. You can even
sign up for a test account on an True64 or Linux/Alpha system.


>If it is doing that, perhaps it could be convinced not to with
>explicit casts, say
>
>memcpy((void *) &sumX, (void *) DatumGetIntervalP(transdatums[0]),
>sizeof(Interval));
>memcpy((void *) &N, (void *) DatumGetIntervalP(transdatums[1]),
>sizeof(Interval));

Nope, this does not fix it. Compiling timestamp.c with the additional
options "-noinline -nointrinsic" does, but I would still hesitate to
use this on the whole project.


>(note similar code in interval_avg would also need to be fixed).  If
>that works it'd be nicer than making a global reduction in optimization
>level...

I've got a rather ugly but usable workaround. See attached timestamp.c
If you can think of anything better, I'm open to suggestions.
/*-------------------------------------------------------------------------
 *
 * timestamp.c
 *      Functions for the built-in SQL92 type "timestamp" and "interval".
 *
 * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *      $Header: /projects/cvsroot/pgsql/src/backend/utils/adt/timestamp.c,v 1.59 2001/10/25 05:49:45 momjian Exp $
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include <ctype.h>
#include <math.h>
#include <errno.h>
#include <sys/types.h>
#include <float.h>
#include <limits.h>

#include "access/hash.h"
#include "access/xact.h"
#include "miscadmin.h"
#include "utils/array.h"
#include "utils/builtins.h"


static double time2t(const int hour, const int min, const double sec);
static int    EncodeSpecialTimestamp(Timestamp dt, char *str);
static Timestamp dt2local(Timestamp dt, int timezone);
static void AdjustTimestampForTypmod(Timestamp *time, int32 typmod);
static void AdjustIntervalForTypmod(Interval *interval, int32 typmod);


/*****************************************************************************
 *     USER I/O ROUTINES                                                         *
 *****************************************************************************/

/* timestamp_in()
 * Convert a string to internal form.
 */
Datum
timestamp_in(PG_FUNCTION_ARGS)
{
    char       *str = PG_GETARG_CSTRING(0);

#ifdef NOT_USED
    Oid            typelem = PG_GETARG_OID(1);
#endif
    int32        typmod = PG_GETARG_INT32(2);
    Timestamp    result;
    double        fsec;
    struct tm    tt,
               *tm = &tt;
    int            tz;
    int            dtype;
    int            nf;
    char       *field[MAXDATEFIELDS];
    int            ftype[MAXDATEFIELDS];
    char        lowstr[MAXDATELEN + 1];

    if ((ParseDateTime(str, lowstr, field, ftype, MAXDATEFIELDS, &nf) != 0)
      || (DecodeDateTime(field, ftype, nf, &dtype, tm, &fsec, &tz) != 0))
        elog(ERROR, "Bad timestamp external representation '%s'", str);

    switch (dtype)
    {
        case DTK_DATE:
            if (tm2timestamp(tm, fsec, NULL, &result) != 0)
                elog(ERROR, "TIMESTAMP out of range '%s'", str);
            break;

        case DTK_EPOCH:
            result = SetEpochTimestamp();
            break;

        case DTK_LATE:
            TIMESTAMP_NOEND(result);
            break;

        case DTK_EARLY:
            TIMESTAMP_NOBEGIN(result);
            break;

        case DTK_INVALID:
            elog(ERROR, "TIMESTAMP '%s' no longer supported", str);
            TIMESTAMP_NOEND(result);
            break;

        default:
            elog(ERROR, "TIMESTAMP '%s' not parsed; internal coding error", str);
            TIMESTAMP_NOEND(result);
    }

    AdjustTimestampForTypmod(&result, typmod);

    PG_RETURN_TIMESTAMP(result);
}

/* timestamp_out()
 * Convert a timestamp to external form.
 */
Datum
timestamp_out(PG_FUNCTION_ARGS)
{
    Timestamp    timestamp = PG_GETARG_TIMESTAMP(0);
    char       *result;
    struct tm    tt,
               *tm = &tt;
    double        fsec;
    char       *tzn = NULL;
    char        buf[MAXDATELEN + 1];

    if (TIMESTAMP_NOT_FINITE(timestamp))
        EncodeSpecialTimestamp(timestamp, buf);
    else if (timestamp2tm(timestamp, NULL, tm, &fsec, NULL) == 0)
        EncodeDateTime(tm, fsec, NULL, &tzn, DateStyle, buf);
    else
        elog(ERROR, "Unable to format timestamp; internal coding error");

    result = pstrdup(buf);
    PG_RETURN_CSTRING(result);
}

/* timestamp_scale()
 * Adjust time type for specified scale factor.
 * Used by PostgreSQL type system to stuff columns.
 */
Datum
timestamp_scale(PG_FUNCTION_ARGS)
{
    Timestamp    timestamp = PG_GETARG_TIMESTAMP(0);
    int32        typmod = PG_GETARG_INT32(1);
    Timestamp    result;

    result = timestamp;

    AdjustTimestampForTypmod(&result, typmod);

    PG_RETURN_TIMESTAMP(result);
}

static void
AdjustTimestampForTypmod(Timestamp *time, int32 typmod)
{
    if (!TIMESTAMP_NOT_FINITE(*time) &&
        (typmod >= 0) && (typmod <= 13))
    {
        static double TimestampScale = 1;
        static int32 TimestampTypmod = 0;

        if (typmod != TimestampTypmod)
        {
            TimestampScale = pow(10.0, typmod);
            TimestampTypmod = typmod;
        }

        *time = (rint(((double) *time) * TimestampScale) / TimestampScale);
    }
}


/* timestamptz_in()
 * Convert a string to internal form.
 */
Datum
timestamptz_in(PG_FUNCTION_ARGS)
{
    char       *str = PG_GETARG_CSTRING(0);

#ifdef NOT_USED
    Oid            typelem = PG_GETARG_OID(1);
#endif
    int32        typmod = PG_GETARG_INT32(2);
    TimestampTz result;
    double        fsec;
    struct tm    tt,
               *tm = &tt;
    int            tz;
    int            dtype;
    int            nf;
    char       *field[MAXDATEFIELDS];
    int            ftype[MAXDATEFIELDS];
    char        lowstr[MAXDATELEN + 1];

    if ((ParseDateTime(str, lowstr, field, ftype, MAXDATEFIELDS, &nf) != 0)
      || (DecodeDateTime(field, ftype, nf, &dtype, tm, &fsec, &tz) != 0))
        elog(ERROR, "Bad timestamp external representation '%s'", str);

    switch (dtype)
    {
        case DTK_DATE:
            if (tm2timestamp(tm, fsec, &tz, &result) != 0)
                elog(ERROR, "TIMESTAMP WITH TIME ZONE out of range '%s'", str);
            break;

        case DTK_EPOCH:
            result = SetEpochTimestamp();
            break;

        case DTK_LATE:
            TIMESTAMP_NOEND(result);
            break;

        case DTK_EARLY:
            TIMESTAMP_NOBEGIN(result);
            break;

        case DTK_INVALID:
            elog(ERROR, "TIMESTAMP WITH TIME ZONE '%s' no longer supported", str);
            TIMESTAMP_NOEND(result);
            break;

        default:
            elog(ERROR, "TIMESTAMP WITH TIME ZONE '%s' not parsed; internal coding error", str);
            TIMESTAMP_NOEND(result);
    }

    AdjustTimestampForTypmod(&result, typmod);

    PG_RETURN_TIMESTAMPTZ(result);
}

/* timestamptz_out()
 * Convert a timestamp to external form.
 */
Datum
timestamptz_out(PG_FUNCTION_ARGS)
{
    TimestampTz dt = PG_GETARG_TIMESTAMP(0);
    char       *result;
    int            tz;
    struct tm    tt,
               *tm = &tt;
    double        fsec;
    char       *tzn;
    char        buf[MAXDATELEN + 1];

    if (TIMESTAMP_NOT_FINITE(dt))
        EncodeSpecialTimestamp(dt, buf);
    else if (timestamp2tm(dt, &tz, tm, &fsec, &tzn) == 0)
        EncodeDateTime(tm, fsec, &tz, &tzn, DateStyle, buf);
    else
        elog(ERROR, "Unable to format timestamp with time zone; internal coding error");

    result = pstrdup(buf);
    PG_RETURN_CSTRING(result);
}

/* timestamptz_scale()
 * Adjust time type for specified scale factor.
 * Used by PostgreSQL type system to stuff columns.
 */
Datum
timestamptz_scale(PG_FUNCTION_ARGS)
{
    TimestampTz timestamp = PG_GETARG_TIMESTAMP(0);
    int32        typmod = PG_GETARG_INT32(1);
    TimestampTz result;

    result = timestamp;

    AdjustTimestampForTypmod(&result, typmod);

    PG_RETURN_TIMESTAMPTZ(result);
}


/* interval_in()
 * Convert a string to internal form.
 *
 * External format(s):
 *    Uses the generic date/time parsing and decoding routines.
 */
Datum
interval_in(PG_FUNCTION_ARGS)
{
    char       *str = PG_GETARG_CSTRING(0);

#ifdef NOT_USED
    Oid            typelem = PG_GETARG_OID(1);
#endif
    int32        typmod = PG_GETARG_INT32(2);
    Interval   *result;
    double        fsec;
    struct tm    tt,
               *tm = &tt;
    int            dtype;
    int            nf;
    char       *field[MAXDATEFIELDS];
    int            ftype[MAXDATEFIELDS];
    char        lowstr[MAXDATELEN + 1];

    tm->tm_year = 0;
    tm->tm_mon = 0;
    tm->tm_mday = 0;
    tm->tm_hour = 0;
    tm->tm_min = 0;
    tm->tm_sec = 0;
    fsec = 0;

    if ((ParseDateTime(str, lowstr, field, ftype, MAXDATEFIELDS, &nf) != 0)
        || (DecodeDateDelta(field, ftype, nf, &dtype, tm, &fsec) != 0))
        elog(ERROR, "Bad interval external representation '%s'", str);

    result = (Interval *) palloc(sizeof(Interval));

    switch (dtype)
    {
        case DTK_DELTA:
            if (tm2interval(tm, fsec, result) != 0)
                elog(ERROR, "Bad interval external representation '%s'", str);
            AdjustIntervalForTypmod(result, typmod);
            break;

        case DTK_INVALID:
            elog(ERROR, "Interval '%s' no longer supported", str);
            break;

        default:
            elog(ERROR, "Interval '%s' not parsed; internal coding error", str);
    }

    PG_RETURN_INTERVAL_P(result);
}

/* interval_out()
 * Convert a time span to external form.
 */
Datum
interval_out(PG_FUNCTION_ARGS)
{
    Interval   *span = PG_GETARG_INTERVAL_P(0);
    char       *result;
    struct tm    tt,
               *tm = &tt;
    double        fsec;
    char        buf[MAXDATELEN + 1];

    if (interval2tm(*span, tm, &fsec) != 0)
        elog(ERROR, "Unable to encode interval; internal coding error");

    if (EncodeTimeSpan(tm, fsec, DateStyle, buf) != 0)
        elog(ERROR, "Unable to format interval; internal coding error");

    result = pstrdup(buf);
    PG_RETURN_CSTRING(result);
}

/* interval_scale()
 * Adjust interval type for specified fields.
 * Used by PostgreSQL type system to stuff columns.
 */
Datum
interval_scale(PG_FUNCTION_ARGS)
{
    Interval   *interval = PG_GETARG_INTERVAL_P(0);
    int32        typmod = PG_GETARG_INT32(1);
    Interval   *result;

    result = palloc(sizeof(Interval));
    *result = *interval;

    AdjustIntervalForTypmod(result, typmod);

    PG_RETURN_INTERVAL_P(result);
}

#define MASK(b) (1 << (b))

static void
AdjustIntervalForTypmod(Interval *interval, int32 typmod)
{
    if (typmod != -1)
    {
        int            range = ((typmod >> 16) & 0x7FFF);
        int            precision = (typmod & 0xFFFF);

        if (range == 0x7FFF)
        {
            /* Do nothing... */
        }
        else if (range == MASK(YEAR))
        {
            interval->month = ((interval->month / 12) * 12);
            interval->time = 0;
        }
        else if (range == MASK(MONTH))
        {
            interval->month %= 12;
            interval->time = 0;
        }
        /* YEAR TO MONTH */
        else if (range == (MASK(YEAR) | MASK(MONTH)))
            interval->time = 0;
        else if (range == MASK(DAY))
        {
            interval->month = 0;
            interval->time = (((int) (interval->time / 86400)) * 86400);
        }
        else if (range == MASK(HOUR))
        {
            double        day;

            interval->month = 0;
            TMODULO(interval->time, day, 86400.0);
            interval->time = (((int) (interval->time / 3600)) * 3600.0);
        }
        else if (range == MASK(MINUTE))
        {
            double        hour;

            interval->month = 0;
            TMODULO(interval->time, hour, 3600.0);
            interval->time = (((int) (interval->time / 60)) * 60);
        }
        else if (range == MASK(SECOND))
        {
            double        hour;

            interval->month = 0;
            TMODULO(interval->time, hour, 60.0);
/*            interval->time = (int)(interval->time); */
        }
        /* DAY TO HOUR */
        else if (range == (MASK(DAY) | MASK(HOUR)))
        {
            interval->month = 0;
            interval->time = (((int) (interval->time / 3600)) * 3600);
        }
        /* DAY TO MINUTE */
        else if (range == (MASK(DAY) | MASK(HOUR) | MASK(MINUTE)))
        {
            interval->month = 0;
            interval->time = (((int) (interval->time / 60)) * 60);
        }
        /* DAY TO SECOND */
        else if (range == (MASK(DAY) | MASK(HOUR) | MASK(MINUTE) | MASK(SECOND)))
            interval->month = 0;
        /* HOUR TO MINUTE */
        else if (range == (MASK(HOUR) | MASK(MINUTE)))
        {
            double        day;

            interval->month = 0;
            TMODULO(interval->time, day, 86400.0);
            interval->time = (((int) (interval->time / 60)) * 60);
        }
        /* HOUR TO SECOND */
        else if (range == (MASK(HOUR) | MASK(MINUTE) | MASK(SECOND)))
        {
            double        day;

            interval->month = 0;
            TMODULO(interval->time, day, 86400.0);
        }
        /* MINUTE TO SECOND */
        else if (range == (MASK(MINUTE) | MASK(SECOND)))
        {
            double        hour;

            interval->month = 0;
            TMODULO(interval->time, hour, 3600.0);
        }
        else
            elog(ERROR, "AdjustIntervalForTypmod(): internal coding error");

        if (precision != 0xFFFF)
        {
            static double IntervalScale = 1;
            static int    IntervalTypmod = 0;

            if (precision != IntervalTypmod)
            {
                IntervalTypmod = precision;
                IntervalScale = pow(10.0, IntervalTypmod);
            }

            /*
             * Hmm. For the time field, we can get to a large value since
             * we store everything related to an absolute interval (e.g.
             * years worth of days) in this one field. So we have
             * precision problems doing rint() on this field if the field
             * is too large. This resulted in an annoying "...0001"
             * appended to the printed result on my Linux box. I hate
             * doing an expensive math operation like log10() to avoid
             * this, but what else can we do?? - thomas 2001-10-19
             */
            if ((log10(interval->time) + IntervalTypmod) <= 13)
                interval->time = (rint(interval->time * IntervalScale) / IntervalScale);
        }
    }

    return;
}


/* EncodeSpecialTimestamp()
 * Convert reserved timestamp data type to string.
 */
static int
EncodeSpecialTimestamp(Timestamp dt, char *str)
{
    if (TIMESTAMP_IS_NOBEGIN(dt))
        strcpy(str, EARLY);
    else if (TIMESTAMP_IS_NOEND(dt))
        strcpy(str, LATE);
    else
        return FALSE;

    return TRUE;
}    /* EncodeSpecialTimestamp() */

Datum
now(PG_FUNCTION_ARGS)
{
    TimestampTz result;
    AbsoluteTime sec;
    int            usec;

    sec = GetCurrentTransactionStartTimeUsec(&usec);

    result = (sec + (usec * 1.0e-6) - ((date2j(2000, 1, 1) - date2j(1970, 1, 1)) * 86400));

    PG_RETURN_TIMESTAMPTZ(result);
}

void
dt2time(Timestamp jd, int *hour, int *min, double *sec)
{
    double        time;

    time = jd;

    *hour = (time / 3600);
    time -= ((*hour) * 3600);
    *min = (time / 60);
    time -= ((*min) * 60);
    *sec = JROUND(time);

    return;
}    /* dt2time() */


/* timestamp2tm()
 * Convert timestamp data type to POSIX time structure.
 * Note that year is _not_ 1900-based, but is an explicit full value.
 * Also, month is one-based, _not_ zero-based.
 * Returns:
 *     0 on success
 *    -1 on out of range
 *
 * For dates within the system-supported time_t range, convert to the
 *    local time zone. If out of this range, leave as GMT. - tgl 97/05/27
 */
int
timestamp2tm(Timestamp dt, int *tzp, struct tm * tm, double *fsec, char **tzn)
{
    double        date,
                date0,
                time,
                sec;
    time_t        utime;

#if defined(HAVE_TM_ZONE) || defined(HAVE_INT_TIMEZONE)
    struct tm  *tx;
#endif

    date0 = date2j(2000, 1, 1);

    /*
     * If HasCTZSet is true then we have a brute force time zone
     * specified. Go ahead and rotate to the local time zone since we will
     * later bypass any calls which adjust the tm fields.
     */
    if (HasCTZSet && (tzp != NULL))
        dt -= CTimeZone;

    time = dt;
    TMODULO(time, date, 86400e0);

    if (time < 0)
    {
        time += 86400;
        date -= 1;
    }

    /* Julian day routine does not work for negative Julian days */
    if (date < -date0)
        return -1;

    /* add offset to go from J2000 back to standard Julian date */
    date += date0;

    j2date((int) date, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
    dt2time(time, &tm->tm_hour, &tm->tm_min, &sec);

    *fsec = JROUND(sec);
    TMODULO(*fsec, tm->tm_sec, 1e0);

    if (tzp != NULL)
    {
        /*
         * We have a brute force time zone per SQL99? Then use it without
         * change since we have already rotated to the time zone.
         */
        if (HasCTZSet)
        {
            *tzp = CTimeZone;
            tm->tm_isdst = 0;
#if defined(HAVE_TM_ZONE)
            tm->tm_gmtoff = CTimeZone;
            tm->tm_zone = NULL;
#endif
            if (tzn != NULL)
                *tzn = NULL;
        }

        /*
         * Does this fall within the capabilities of the localtime()
         * interface? Then use this to rotate to the local time zone.
         */
        else if (IS_VALID_UTIME(tm->tm_year, tm->tm_mon, tm->tm_mday))
        {
            utime = (dt + (date0 - date2j(1970, 1, 1)) * 86400);

#if defined(HAVE_TM_ZONE) || defined(HAVE_INT_TIMEZONE)
            tx = localtime(&utime);
#ifdef NO_MKTIME_BEFORE_1970
            if (tx->tm_year < 70 && tx->tm_isdst == 1)
            {
                utime -= 3600;
                tx = localtime(&utime);
                tx->tm_isdst = 0;
            }
#endif
            tm->tm_year = tx->tm_year + 1900;
            tm->tm_mon = tx->tm_mon + 1;
            tm->tm_mday = tx->tm_mday;
            tm->tm_hour = tx->tm_hour;
            tm->tm_min = tx->tm_min;
#if NOT_USED
/* XXX HACK
 * Argh! My Linux box puts in a 1 second offset for dates less than 1970
 *    but only if the seconds field was non-zero. So, don't copy the seconds
 *    field and instead carry forward from the original - thomas 97/06/18
 * Note that GNU/Linux uses the standard freeware zic package as do
 *    many other platforms so this may not be GNU/Linux/ix86-specific.
 * Still shows a problem on my up to date Linux box - thomas 2001-01-17
 */
            tm->tm_sec = tx->tm_sec;
#endif
            tm->tm_isdst = tx->tm_isdst;

#if defined(HAVE_TM_ZONE)
            tm->tm_gmtoff = tx->tm_gmtoff;
            tm->tm_zone = tx->tm_zone;

            *tzp = -(tm->tm_gmtoff);    /* tm_gmtoff is Sun/DEC-ism */
            if (tzn != NULL)
                *tzn = (char *) tm->tm_zone;
#elif defined(HAVE_INT_TIMEZONE)
            *tzp = ((tm->tm_isdst > 0) ? (TIMEZONE_GLOBAL - 3600) : TIMEZONE_GLOBAL);
            if (tzn != NULL)
                *tzn = tzname[(tm->tm_isdst > 0)];
#endif

#else                            /* not (HAVE_TM_ZONE || HAVE_INT_TIMEZONE) */
            *tzp = CTimeZone;    /* V7 conventions; don't know timezone? */
            if (tzn != NULL)
                *tzn = CTZName;
#endif

            dt = dt2local(dt, *tzp);
        }
        else
        {
            *tzp = 0;
            /* Mark this as *no* time zone available */
            tm->tm_isdst = -1;
            if (tzn != NULL)
                *tzn = NULL;
        }
    }
    else
    {
        tm->tm_isdst = -1;
        if (tzn != NULL)
            *tzn = NULL;
    }

    return 0;
}    /* timestamp2tm() */


/* tm2timestamp()
 * Convert a tm structure to a timestamp data type.
 * Note that year is _not_ 1900-based, but is an explicit full value.
 * Also, month is one-based, _not_ zero-based.
 */
int
tm2timestamp(struct tm * tm, double fsec, int *tzp, Timestamp *result)
{

    double        date,
                time;

    /* Julian day routines are not correct for negative Julian days */
    if (!IS_VALID_JULIAN(tm->tm_year, tm->tm_mon, tm->tm_mday))
        return -1;

    date = date2j(tm->tm_year, tm->tm_mon, tm->tm_mday) - date2j(2000, 1, 1);
    time = time2t(tm->tm_hour, tm->tm_min, (tm->tm_sec + fsec));
    *result = (date * 86400 + time);
    if (tzp != NULL)
        *result = dt2local(*result, -(*tzp));

    return 0;
}    /* tm2timestamp() */


/* interval2tm()
 * Convert a interval data type to a tm structure.
 */
int
interval2tm(Interval span, struct tm * tm, float8 *fsec)
{
    double        time;

    if (span.month != 0)
    {
        tm->tm_year = span.month / 12;
        tm->tm_mon = span.month % 12;

    }
    else
    {
        tm->tm_year = 0;
        tm->tm_mon = 0;
    }

#ifdef ROUND_ALL
    time = JROUND(span.time);
#else
    time = span.time;
#endif

    TMODULO(time, tm->tm_mday, 86400e0);
    TMODULO(time, tm->tm_hour, 3600e0);
    TMODULO(time, tm->tm_min, 60e0);
    TMODULO(time, tm->tm_sec, 1e0);
    *fsec = time;

    return 0;
}    /* interval2tm() */

int
tm2interval(struct tm * tm, double fsec, Interval *span)
{
    span->month = ((tm->tm_year * 12) + tm->tm_mon);
    span->time = ((((((tm->tm_mday * 24.0)
                      + tm->tm_hour) * 60.0)
                    + tm->tm_min) * 60.0)
                  + tm->tm_sec);
    span->time = JROUND(span->time + fsec);

    return 0;
}    /* tm2interval() */

static double
time2t(const int hour, const int min, const double sec)
{
    return (((hour * 60) + min) * 60) + sec;
}    /* time2t() */

static Timestamp
dt2local(Timestamp dt, int tz)
{
    dt -= tz;
    dt = JROUND(dt);
    return dt;
}    /* dt2local() */


/*****************************************************************************
 *     PUBLIC ROUTINES                                                         *
 *****************************************************************************/


Datum
timestamp_finite(PG_FUNCTION_ARGS)
{
    Timestamp    timestamp = PG_GETARG_TIMESTAMP(0);

    PG_RETURN_BOOL(!TIMESTAMP_NOT_FINITE(timestamp));
}

Datum
interval_finite(PG_FUNCTION_ARGS)
{
    PG_RETURN_BOOL(true);
}


/*----------------------------------------------------------
 *    Relational operators for timestamp.
 *---------------------------------------------------------*/

void
GetEpochTime(struct tm * tm)
{
    struct tm  *t0;
    time_t        epoch = 0;

    t0 = gmtime(&epoch);

    tm->tm_year = t0->tm_year;
    tm->tm_mon = t0->tm_mon;
    tm->tm_mday = t0->tm_mday;
    tm->tm_hour = t0->tm_hour;
    tm->tm_min = t0->tm_min;
    tm->tm_sec = t0->tm_sec;

    if (tm->tm_year < 1900)
        tm->tm_year += 1900;
    tm->tm_mon++;

    return;
}    /* GetEpochTime() */

Timestamp
SetEpochTimestamp(void)
{
    Timestamp    dt;
    struct tm    tt,
               *tm = &tt;

    GetEpochTime(tm);
    tm2timestamp(tm, 0, NULL, &dt);

    return dt;
}    /* SetEpochTimestamp() */

/*
 *        timestamp_relop - is timestamp1 relop timestamp2
 *
 *        collate invalid timestamp at the end
 */
static int
timestamp_cmp_internal(Timestamp dt1, Timestamp dt2)
{
    return ((dt1 < dt2) ? -1 : ((dt1 > dt2) ? 1 : 0));
}

Datum
timestamp_eq(PG_FUNCTION_ARGS)
{
    Timestamp    dt1 = PG_GETARG_TIMESTAMP(0);
    Timestamp    dt2 = PG_GETARG_TIMESTAMP(1);

    PG_RETURN_BOOL(timestamp_cmp_internal(dt1, dt2) == 0);
}

Datum
timestamp_ne(PG_FUNCTION_ARGS)
{
    Timestamp    dt1 = PG_GETARG_TIMESTAMP(0);
    Timestamp    dt2 = PG_GETARG_TIMESTAMP(1);

    PG_RETURN_BOOL(timestamp_cmp_internal(dt1, dt2) != 0);
}

Datum
timestamp_lt(PG_FUNCTION_ARGS)
{
    Timestamp    dt1 = PG_GETARG_TIMESTAMP(0);
    Timestamp    dt2 = PG_GETARG_TIMESTAMP(1);

    PG_RETURN_BOOL(timestamp_cmp_internal(dt1, dt2) < 0);
}

Datum
timestamp_gt(PG_FUNCTION_ARGS)
{
    Timestamp    dt1 = PG_GETARG_TIMESTAMP(0);
    Timestamp    dt2 = PG_GETARG_TIMESTAMP(1);

    PG_RETURN_BOOL(timestamp_cmp_internal(dt1, dt2) > 0);
}

Datum
timestamp_le(PG_FUNCTION_ARGS)
{
    Timestamp    dt1 = PG_GETARG_TIMESTAMP(0);
    Timestamp    dt2 = PG_GETARG_TIMESTAMP(1);

    PG_RETURN_BOOL(timestamp_cmp_internal(dt1, dt2) <= 0);
}

Datum
timestamp_ge(PG_FUNCTION_ARGS)
{
    Timestamp    dt1 = PG_GETARG_TIMESTAMP(0);
    Timestamp    dt2 = PG_GETARG_TIMESTAMP(1);

    PG_RETURN_BOOL(timestamp_cmp_internal(dt1, dt2) >= 0);
}

Datum
timestamp_cmp(PG_FUNCTION_ARGS)
{
    Timestamp    dt1 = PG_GETARG_TIMESTAMP(0);
    Timestamp    dt2 = PG_GETARG_TIMESTAMP(1);

    PG_RETURN_INT32(timestamp_cmp_internal(dt1, dt2));
}


/*
 *        interval_relop    - is interval1 relop interval2
 *
 *        collate invalid interval at the end
 */
static int
interval_cmp_internal(Interval *interval1, Interval *interval2)
{
    double        span1,
                span2;

    span1 = interval1->time;
    if (interval1->month != 0)
        span1 += (interval1->month * (30.0 * 86400));
    span2 = interval2->time;
    if (interval2->month != 0)
        span2 += (interval2->month * (30.0 * 86400));

    return ((span1 < span2) ? -1 : (span1 > span2) ? 1 : 0);
}

Datum
interval_eq(PG_FUNCTION_ARGS)
{
    Interval   *interval1 = PG_GETARG_INTERVAL_P(0);
    Interval   *interval2 = PG_GETARG_INTERVAL_P(1);

    PG_RETURN_BOOL(interval_cmp_internal(interval1, interval2) == 0);
}

Datum
interval_ne(PG_FUNCTION_ARGS)
{
    Interval   *interval1 = PG_GETARG_INTERVAL_P(0);
    Interval   *interval2 = PG_GETARG_INTERVAL_P(1);

    PG_RETURN_BOOL(interval_cmp_internal(interval1, interval2) != 0);
}

Datum
interval_lt(PG_FUNCTION_ARGS)
{
    Interval   *interval1 = PG_GETARG_INTERVAL_P(0);
    Interval   *interval2 = PG_GETARG_INTERVAL_P(1);

    PG_RETURN_BOOL(interval_cmp_internal(interval1, interval2) < 0);
}

Datum
interval_gt(PG_FUNCTION_ARGS)
{
    Interval   *interval1 = PG_GETARG_INTERVAL_P(0);
    Interval   *interval2 = PG_GETARG_INTERVAL_P(1);

    PG_RETURN_BOOL(interval_cmp_internal(interval1, interval2) > 0);
}

Datum
interval_le(PG_FUNCTION_ARGS)
{
    Interval   *interval1 = PG_GETARG_INTERVAL_P(0);
    Interval   *interval2 = PG_GETARG_INTERVAL_P(1);

    PG_RETURN_BOOL(interval_cmp_internal(interval1, interval2) <= 0);
}

Datum
interval_ge(PG_FUNCTION_ARGS)
{
    Interval   *interval1 = PG_GETARG_INTERVAL_P(0);
    Interval   *interval2 = PG_GETARG_INTERVAL_P(1);

    PG_RETURN_BOOL(interval_cmp_internal(interval1, interval2) >= 0);
}

Datum
interval_cmp(PG_FUNCTION_ARGS)
{
    Interval   *interval1 = PG_GETARG_INTERVAL_P(0);
    Interval   *interval2 = PG_GETARG_INTERVAL_P(1);

    PG_RETURN_INT32(interval_cmp_internal(interval1, interval2));
}

/*
 * interval, being an unusual size, needs a specialized hash function.
 */
Datum
interval_hash(PG_FUNCTION_ARGS)
{
    Interval   *key = PG_GETARG_INTERVAL_P(0);

    /*
     * Specify hash length as sizeof(double) + sizeof(int4), not as
     * sizeof(Interval), so that any garbage pad bytes in the structure
     * won't be included in the hash!
     */
    return hash_any((char *) key, sizeof(double) + sizeof(int4));
}

/* overlaps_timestamp() --- implements the SQL92 OVERLAPS operator.
 *
 * Algorithm is per SQL92 spec.  This is much harder than you'd think
 * because the spec requires us to deliver a non-null answer in some cases
 * where some of the inputs are null.
 */
Datum
overlaps_timestamp(PG_FUNCTION_ARGS)
{
    /*
     * The arguments are Timestamps, but we leave them as generic Datums
     * to avoid unnecessary conversions between value and reference forms
     * --- not to mention possible dereferences of null pointers.
     */
    Datum        ts1 = PG_GETARG_DATUM(0);
    Datum        te1 = PG_GETARG_DATUM(1);
    Datum        ts2 = PG_GETARG_DATUM(2);
    Datum        te2 = PG_GETARG_DATUM(3);
    bool        ts1IsNull = PG_ARGISNULL(0);
    bool        te1IsNull = PG_ARGISNULL(1);
    bool        ts2IsNull = PG_ARGISNULL(2);
    bool        te2IsNull = PG_ARGISNULL(3);

#define TIMESTAMP_GT(t1,t2) \
    DatumGetBool(DirectFunctionCall2(timestamp_gt,t1,t2))
#define TIMESTAMP_LT(t1,t2) \
    DatumGetBool(DirectFunctionCall2(timestamp_lt,t1,t2))

    /*
     * If both endpoints of interval 1 are null, the result is null
     * (unknown). If just one endpoint is null, take ts1 as the non-null
     * one. Otherwise, take ts1 as the lesser endpoint.
     */
    if (ts1IsNull)
    {
        if (te1IsNull)
            PG_RETURN_NULL();
        /* swap null for non-null */
        ts1 = te1;
        te1IsNull = true;
    }
    else if (!te1IsNull)
    {
        if (TIMESTAMP_GT(ts1, te1))
        {
            Datum        tt = ts1;

            ts1 = te1;
            te1 = tt;
        }
    }

    /* Likewise for interval 2. */
    if (ts2IsNull)
    {
        if (te2IsNull)
            PG_RETURN_NULL();
        /* swap null for non-null */
        ts2 = te2;
        te2IsNull = true;
    }
    else if (!te2IsNull)
    {
        if (TIMESTAMP_GT(ts2, te2))
        {
            Datum        tt = ts2;

            ts2 = te2;
            te2 = tt;
        }
    }

    /*
     * At this point neither ts1 nor ts2 is null, so we can consider three
     * cases: ts1 > ts2, ts1 < ts2, ts1 = ts2
     */
    if (TIMESTAMP_GT(ts1, ts2))
    {
        /*
         * This case is ts1 < te2 OR te1 < te2, which may look redundant
         * but in the presence of nulls it's not quite completely so.
         */
        if (te2IsNull)
            PG_RETURN_NULL();
        if (TIMESTAMP_LT(ts1, te2))
            PG_RETURN_BOOL(true);
        if (te1IsNull)
            PG_RETURN_NULL();

        /*
         * If te1 is not null then we had ts1 <= te1 above, and we just
         * found ts1 >= te2, hence te1 >= te2.
         */
        PG_RETURN_BOOL(false);
    }
    else if (TIMESTAMP_LT(ts1, ts2))
    {
        /* This case is ts2 < te1 OR te2 < te1 */
        if (te1IsNull)
            PG_RETURN_NULL();
        if (TIMESTAMP_LT(ts2, te1))
            PG_RETURN_BOOL(true);
        if (te2IsNull)
            PG_RETURN_NULL();

        /*
         * If te2 is not null then we had ts2 <= te2 above, and we just
         * found ts2 >= te1, hence te2 >= te1.
         */
        PG_RETURN_BOOL(false);
    }
    else
    {
        /*
         * For ts1 = ts2 the spec says te1 <> te2 OR te1 = te2, which is a
         * rather silly way of saying "true if both are nonnull, else
         * null".
         */
        if (te1IsNull || te2IsNull)
            PG_RETURN_NULL();
        PG_RETURN_BOOL(true);
    }

#undef TIMESTAMP_GT
#undef TIMESTAMP_LT
}


/*----------------------------------------------------------
 *    "Arithmetic" operators on date/times.
 *---------------------------------------------------------*/

/* We are currently sharing some code between timestamp and timestamptz.
 * The comparison functions are among them. - thomas 2001-09-25
 */
Datum
timestamp_smaller(PG_FUNCTION_ARGS)
{
    Timestamp    dt1 = PG_GETARG_TIMESTAMP(0);
    Timestamp    dt2 = PG_GETARG_TIMESTAMP(1);
    Timestamp    result;

    result = ((dt2 < dt1) ? dt2 : dt1);

    PG_RETURN_TIMESTAMP(result);
}

Datum
timestamp_larger(PG_FUNCTION_ARGS)
{
    Timestamp    dt1 = PG_GETARG_TIMESTAMP(0);
    Timestamp    dt2 = PG_GETARG_TIMESTAMP(1);
    Timestamp    result;

    result = ((dt2 > dt1) ? dt2 : dt1);

    PG_RETURN_TIMESTAMP(result);
}


Datum
timestamp_mi(PG_FUNCTION_ARGS)
{
    Timestamp    dt1 = PG_GETARG_TIMESTAMP(0);
    Timestamp    dt2 = PG_GETARG_TIMESTAMP(1);
    Interval   *result;

    result = (Interval *) palloc(sizeof(Interval));

    if (TIMESTAMP_NOT_FINITE(dt1) || TIMESTAMP_NOT_FINITE(dt2))
    {
        elog(ERROR, "Unable to subtract non-finite timestamps");
        result->time = 0;
    }
    else
        result->time = JROUND(dt1 - dt2);

    result->month = 0;

    PG_RETURN_INTERVAL_P(result);
}


/* timestamp_pl_span()
 * Add a interval to a timestamp data type.
 * Note that interval has provisions for qualitative year/month
 *    units, so try to do the right thing with them.
 * To add a month, increment the month, and use the same day of month.
 * Then, if the next month has fewer days, set the day of month
 *    to the last day of month.
 * Lastly, add in the "quantitative time".
 */
Datum
timestamp_pl_span(PG_FUNCTION_ARGS)
{
    Timestamp    timestamp = PG_GETARG_TIMESTAMP(0);
    Interval   *span = PG_GETARG_INTERVAL_P(1);
    Timestamp    result;

    if (TIMESTAMP_NOT_FINITE(timestamp))
        result = timestamp;
    else
    {
        if (span->month != 0)
        {
            struct tm    tt,
                       *tm = &tt;
            double        fsec;

            if (timestamp2tm(timestamp, NULL, tm, &fsec, NULL) == 0)
            {
                tm->tm_mon += span->month;
                if (tm->tm_mon > 12)
                {
                    tm->tm_year += ((tm->tm_mon - 1) / 12);
                    tm->tm_mon = (((tm->tm_mon - 1) % 12) + 1);
                }
                else if (tm->tm_mon < 1)
                {
                    tm->tm_year += ((tm->tm_mon / 12) - 1);
                    tm->tm_mon = ((tm->tm_mon % 12) + 12);
                }

                /* adjust for end of month boundary problems... */
                if (tm->tm_mday > day_tab[isleap(tm->tm_year)][tm->tm_mon - 1])
                    tm->tm_mday = (day_tab[isleap(tm->tm_year)][tm->tm_mon - 1]);

                if (tm2timestamp(tm, fsec, NULL, ×tamp) != 0)
                {
                    elog(ERROR, "Unable to add TIMESTAMP and INTERVAL"
                         "\n\ttimestamp_pl_span() internal error encoding timestamp");
                    PG_RETURN_NULL();
                }
            }
            else
            {
                elog(ERROR, "Unable to add TIMESTAMP and INTERVAL"
                     "\n\ttimestamp_pl_span() internal error decoding timestamp");
                PG_RETURN_NULL();
            }
        }

#ifdef ROUND_ALL
        timestamp = JROUND(timestamp + span->time);
#else
        timestamp += span->time;
#endif

        result = timestamp;
    }

    PG_RETURN_TIMESTAMP(result);
}

Datum
timestamp_mi_span(PG_FUNCTION_ARGS)
{
    Timestamp    timestamp = PG_GETARG_TIMESTAMP(0);
    Interval   *span = PG_GETARG_INTERVAL_P(1);
    Interval    tspan;

    tspan.month = -span->month;
    tspan.time = -span->time;

    return DirectFunctionCall2(timestamp_pl_span,
                               TimestampGetDatum(timestamp),
                               PointerGetDatum(&tspan));
}


/* timestamp_pl_span()
 * Add a interval to a timestamp with time zone data type.
 * Note that interval has provisions for qualitative year/month
 *    units, so try to do the right thing with them.
 * To add a month, increment the month, and use the same day of month.
 * Then, if the next month has fewer days, set the day of month
 *    to the last day of month.
 * Lastly, add in the "quantitative time".
 */
Datum
timestamptz_pl_span(PG_FUNCTION_ARGS)
{
    TimestampTz timestamp = PG_GETARG_TIMESTAMP(0);
    Interval   *span = PG_GETARG_INTERVAL_P(1);
    TimestampTz result;
    int            tz;
    char       *tzn;

    if (TIMESTAMP_NOT_FINITE(timestamp))
        result = timestamp;
    else
    {
        if (span->month != 0)
        {
            struct tm    tt,
                       *tm = &tt;
            double        fsec;

            if (timestamp2tm(timestamp, &tz, tm, &fsec, &tzn) == 0)
            {
                tm->tm_mon += span->month;
                if (tm->tm_mon > 12)
                {
                    tm->tm_year += ((tm->tm_mon - 1) / 12);
                    tm->tm_mon = (((tm->tm_mon - 1) % 12) + 1);
                }
                else if (tm->tm_mon < 1)
                {
                    tm->tm_year += ((tm->tm_mon / 12) - 1);
                    tm->tm_mon = ((tm->tm_mon % 12) + 12);
                }

                /* adjust for end of month boundary problems... */
                if (tm->tm_mday > day_tab[isleap(tm->tm_year)][tm->tm_mon - 1])
                    tm->tm_mday = (day_tab[isleap(tm->tm_year)][tm->tm_mon - 1]);

                tz = DetermineLocalTimeZone(tm);

                if (tm2timestamp(tm, fsec, &tz, ×tamp) != 0)
                    elog(ERROR, "Unable to add TIMESTAMP and INTERVAL"
                         "\n\ttimestamptz_pl_span() internal error encoding timestamp");
            }
            else
            {
                elog(ERROR, "Unable to add TIMESTAMP and INTERVAL"
                     "\n\ttimestamptz_pl_span() internal error decoding timestamp");
            }
        }

#ifdef ROUND_ALL
        timestamp = JROUND(timestamp + span->time);
#else
        timestamp += span->time;
#endif

        result = timestamp;
    }

    PG_RETURN_TIMESTAMP(result);
}

Datum
timestamptz_mi_span(PG_FUNCTION_ARGS)
{
    TimestampTz timestamp = PG_GETARG_TIMESTAMP(0);
    Interval   *span = PG_GETARG_INTERVAL_P(1);
    Interval    tspan;

    tspan.month = -span->month;
    tspan.time = -span->time;

    return DirectFunctionCall2(timestamp_pl_span,
                               TimestampGetDatum(timestamp),
                               PointerGetDatum(&tspan));
}


Datum
interval_um(PG_FUNCTION_ARGS)
{
    Interval   *interval = PG_GETARG_INTERVAL_P(0);
    Interval   *result;

    result = (Interval *) palloc(sizeof(Interval));

    result->time = -(interval->time);
    result->month = -(interval->month);

    PG_RETURN_INTERVAL_P(result);
}


Datum
interval_smaller(PG_FUNCTION_ARGS)
{
    Interval   *interval1 = PG_GETARG_INTERVAL_P(0);
    Interval   *interval2 = PG_GETARG_INTERVAL_P(1);
    Interval   *result;
    double        span1,
                span2;

    result = (Interval *) palloc(sizeof(Interval));

    span1 = interval1->time;
    if (interval1->month != 0)
        span1 += (interval1->month * (30.0 * 86400));
    span2 = interval2->time;
    if (interval2->month != 0)
        span2 += (interval2->month * (30.0 * 86400));

    if (span2 < span1)
    {
        result->time = interval2->time;
        result->month = interval2->month;
    }
    else
    {
        result->time = interval1->time;
        result->month = interval1->month;
    }

    PG_RETURN_INTERVAL_P(result);
}

Datum
interval_larger(PG_FUNCTION_ARGS)
{
    Interval   *interval1 = PG_GETARG_INTERVAL_P(0);
    Interval   *interval2 = PG_GETARG_INTERVAL_P(1);
    Interval   *result;
    double        span1,
                span2;

    result = (Interval *) palloc(sizeof(Interval));

    span1 = interval1->time;
    if (interval1->month != 0)
        span1 += (interval1->month * (30.0 * 86400));
    span2 = interval2->time;
    if (interval2->month != 0)
        span2 += (interval2->month * (30.0 * 86400));

    if (span2 > span1)
    {
        result->time = interval2->time;
        result->month = interval2->month;
    }
    else
    {
        result->time = interval1->time;
        result->month = interval1->month;
    }

    PG_RETURN_INTERVAL_P(result);
}

Datum
interval_pl(PG_FUNCTION_ARGS)
{
    Interval   *span1 = PG_GETARG_INTERVAL_P(0);
    Interval   *span2 = PG_GETARG_INTERVAL_P(1);
    Interval   *result;

    result = (Interval *) palloc(sizeof(Interval));

    result->month = (span1->month + span2->month);
    result->time = JROUND(span1->time + span2->time);

    PG_RETURN_INTERVAL_P(result);
}

Datum
interval_mi(PG_FUNCTION_ARGS)
{
    Interval   *span1 = PG_GETARG_INTERVAL_P(0);
    Interval   *span2 = PG_GETARG_INTERVAL_P(1);
    Interval   *result;

    result = (Interval *) palloc(sizeof(Interval));

    result->month = (span1->month - span2->month);
    result->time = JROUND(span1->time - span2->time);

    PG_RETURN_INTERVAL_P(result);
}

Datum
interval_mul(PG_FUNCTION_ARGS)
{
    Interval   *span1 = PG_GETARG_INTERVAL_P(0);
    float8        factor = PG_GETARG_FLOAT8(1);
    Interval   *result;
    double        months;

    result = (Interval *) palloc(sizeof(Interval));

    months = (span1->month * factor);
    result->month = rint(months);
    result->time = JROUND(span1->time * factor);
    /* evaluate fractional months as 30 days */
    result->time += JROUND((months - result->month) * 30 * 86400);

    PG_RETURN_INTERVAL_P(result);
}

Datum
mul_d_interval(PG_FUNCTION_ARGS)
{
    /* Args are float8 and Interval *, but leave them as generic Datum */
    Datum        factor = PG_GETARG_DATUM(0);
    Datum        span1 = PG_GETARG_DATUM(1);

    return DirectFunctionCall2(interval_mul, span1, factor);
}

Datum
interval_div(PG_FUNCTION_ARGS)
{
    Interval   *span1 = PG_GETARG_INTERVAL_P(0);
    float8        factor = PG_GETARG_FLOAT8(1);
    Interval   *result;
    double        months;

    result = (Interval *) palloc(sizeof(Interval));

    if (factor == 0.0)
        elog(ERROR, "interval_div: divide by 0.0 error");

    months = (span1->month / factor);
    result->month = rint(months);
    result->time = JROUND(span1->time / factor);
    /* evaluate fractional months as 30 days */
    result->time += JROUND((months - result->month) * 30 * 86400);

    PG_RETURN_INTERVAL_P(result);
}

/*
 * interval_accum and interval_avg implement the AVG(interval) aggregate.
 *
 * The transition datatype for this aggregate is a 2-element array of
 * intervals, where the first is the running sum and the second contains
 * the number of values so far in its 'time' field.  This is a bit ugly
 * but it beats inventing a specialized datatype for the purpose.
 */

Datum
interval_accum(PG_FUNCTION_ARGS)
{
    ArrayType  *transarray = PG_GETARG_ARRAYTYPE_P(0);
    Interval   *newval = PG_GETARG_INTERVAL_P(1);
    Datum       *transdatums;
    int            ndatums;
    Interval    sumX,
                N;
    Interval   *newsum;
    ArrayType  *result;
#if defined( __DECC ) && __alpha == 1
        void         *src1,
            *src2;
#endif

    /* We assume the input is array of interval */
    deconstruct_array(transarray,
                      false, 12, 'd',
                      &transdatums, &ndatums);
    if (ndatums != 2)
        elog(ERROR, "interval_accum: expected 2-element interval array");

    /*
     * XXX memcpy, instead of just extracting a pointer, to work around
     * buggy array code: it won't ensure proper alignment of Interval
     * objects on machines where double requires 8-byte alignment. That
     * should be fixed, but in the meantime...
     */
#if defined( __DECC ) && __alpha == 1
    src1 = (void *)DatumGetIntervalP(transdatums[0]);
    src2 = (void *)DatumGetIntervalP(transdatums[1]);
    memcpy( (void *)&sumX, src1, sizeof(Interval));
    memcpy( (void *)&N, src2, sizeof(Interval));
    if ( src1 == src2 )
    {
        memcpy( src2, src1, sizeof(Interval));
    }
#else
    memcpy( (void *)&sumX, (void *)DatumGetIntervalP(transdatums[0]), sizeof(Interval));
    memcpy( (void *)&N, (void *)DatumGetIntervalP(transdatums[1]), sizeof(Interval));
#endif
    newsum = DatumGetIntervalP(DirectFunctionCall2(interval_pl,
                                                IntervalPGetDatum(&sumX),
                                             IntervalPGetDatum(newval)));
    N.time += 1;

    transdatums[0] = IntervalPGetDatum(newsum);
    transdatums[1] = IntervalPGetDatum(&N);

    result = construct_array(transdatums, 2,
                             false, 12, 'd');

    PG_RETURN_ARRAYTYPE_P(result);
}

Datum
interval_avg(PG_FUNCTION_ARGS)
{
    ArrayType  *transarray = PG_GETARG_ARRAYTYPE_P(0);
    Datum       *transdatums;
    int            ndatums;
    Interval    sumX,
                N;
#if defined( __DECC ) && __alpha == 1
        void         *src1,
            *src2;
#endif
    /* We assume the input is array of interval */
    deconstruct_array(transarray,
                      false, 12, 'd',
                      &transdatums, &ndatums);
    if (ndatums != 2)
        elog(ERROR, "interval_avg: expected 2-element interval array");

    /*
     * XXX memcpy, instead of just extracting a pointer, to work around
     * buggy array code: it won't ensure proper alignment of Interval
     * objects on machines where double requires 8-byte alignment. That
     * should be fixed, but in the meantime...
     */
#if defined( __DECC ) && __alpha == 1
    /*
     * use temp vars to avoid bus errors on non aligned float operations
     * with Compaq C 6.1
     */
    src1 = (void *)DatumGetIntervalP(transdatums[0]);
    src2 = (void *)DatumGetIntervalP(transdatums[1]);
    memcpy( (void *)&sumX, src1, sizeof(Interval));
    memcpy( (void *)&N, src2, sizeof(Interval));
    if ( src1 == src2 ) /* don't let the optimizer eat our temp's */
    {
        memcpy( src2, src1, sizeof(Interval));
    }
#else
    memcpy( (void *)&sumX, (void *)DatumGetIntervalP(transdatums[0]), sizeof(Interval));
    memcpy( (void *)&N, (void *)DatumGetIntervalP(transdatums[1]), sizeof(Interval));
#endif

    /* SQL92 defines AVG of no values to be NULL */
    if (N.time == 0)
        PG_RETURN_NULL();

    return DirectFunctionCall2(interval_div,
                               IntervalPGetDatum(&sumX),
                               Float8GetDatum(N.time));
}

/* timestamp_age()
 * Calculate time difference while retaining year/month fields.
 * Note that this does not result in an accurate absolute time span
 *    since year and month are out of context once the arithmetic
 *    is done.
 */
Datum
timestamp_age(PG_FUNCTION_ARGS)
{
    Timestamp    dt1 = PG_GETARG_TIMESTAMP(0);
    Timestamp    dt2 = PG_GETARG_TIMESTAMP(1);
    Interval   *result;
    double        fsec,
                fsec1,
                fsec2;
    struct tm    tt,
               *tm = &tt;
    struct tm    tt1,
               *tm1 = &tt1;
    struct tm    tt2,
               *tm2 = &tt2;

    result = (Interval *) palloc(sizeof(Interval));

    if ((timestamp2tm(dt1, NULL, tm1, &fsec1, NULL) == 0)
        && (timestamp2tm(dt2, NULL, tm2, &fsec2, NULL) == 0))
    {
        fsec = (fsec1 - fsec2);
        tm->tm_sec = (tm1->tm_sec - tm2->tm_sec);
        tm->tm_min = (tm1->tm_min - tm2->tm_min);
        tm->tm_hour = (tm1->tm_hour - tm2->tm_hour);
        tm->tm_mday = (tm1->tm_mday - tm2->tm_mday);
        tm->tm_mon = (tm1->tm_mon - tm2->tm_mon);
        tm->tm_year = (tm1->tm_year - tm2->tm_year);

        /* flip sign if necessary... */
        if (dt1 < dt2)
        {
            fsec = -fsec;
            tm->tm_sec = -tm->tm_sec;
            tm->tm_min = -tm->tm_min;
            tm->tm_hour = -tm->tm_hour;
            tm->tm_mday = -tm->tm_mday;
            tm->tm_mon = -tm->tm_mon;
            tm->tm_year = -tm->tm_year;
        }

        if (tm->tm_sec < 0)
        {
            tm->tm_sec += 60;
            tm->tm_min--;
        }

        if (tm->tm_min < 0)
        {
            tm->tm_min += 60;
            tm->tm_hour--;
        }

        if (tm->tm_hour < 0)
        {
            tm->tm_hour += 24;
            tm->tm_mday--;
        }

        if (tm->tm_mday < 0)
        {
            if (dt1 < dt2)
            {
                tm->tm_mday += day_tab[isleap(tm1->tm_year)][tm1->tm_mon - 1];
                tm->tm_mon--;
            }
            else
            {
                tm->tm_mday += day_tab[isleap(tm2->tm_year)][tm2->tm_mon - 1];
                tm->tm_mon--;
            }
        }

        if (tm->tm_mon < 0)
        {
            tm->tm_mon += 12;
            tm->tm_year--;
        }

        /* recover sign if necessary... */
        if (dt1 < dt2)
        {
            fsec = -fsec;
            tm->tm_sec = -tm->tm_sec;
            tm->tm_min = -tm->tm_min;
            tm->tm_hour = -tm->tm_hour;
            tm->tm_mday = -tm->tm_mday;
            tm->tm_mon = -tm->tm_mon;
            tm->tm_year = -tm->tm_year;
        }

        if (tm2interval(tm, fsec, result) != 0)
            elog(ERROR, "Unable to encode INTERVAL"
                 "\n\ttimestamp_age() internal coding error");
    }
    else
        elog(ERROR, "Unable to decode TIMESTAMP"
             "\n\ttimestamp_age() internal coding error");

    PG_RETURN_INTERVAL_P(result);
}


/* timestamptz_age()
 * Calculate time difference while retaining year/month fields.
 * Note that this does not result in an accurate absolute time span
 *    since year and month are out of context once the arithmetic
 *    is done.
 */
Datum
timestamptz_age(PG_FUNCTION_ARGS)
{
    TimestampTz dt1 = PG_GETARG_TIMESTAMP(0);
    TimestampTz dt2 = PG_GETARG_TIMESTAMP(1);
    Interval   *result;
    double        fsec,
                fsec1,
                fsec2;
    struct tm    tt,
               *tm = &tt;
    struct tm    tt1,
               *tm1 = &tt1;
    struct tm    tt2,
               *tm2 = &tt2;

    result = (Interval *) palloc(sizeof(Interval));

    if ((timestamp2tm(dt1, NULL, tm1, &fsec1, NULL) == 0)
        && (timestamp2tm(dt2, NULL, tm2, &fsec2, NULL) == 0))
    {
        fsec = (fsec1 - fsec2);
        tm->tm_sec = (tm1->tm_sec - tm2->tm_sec);
        tm->tm_min = (tm1->tm_min - tm2->tm_min);
        tm->tm_hour = (tm1->tm_hour - tm2->tm_hour);
        tm->tm_mday = (tm1->tm_mday - tm2->tm_mday);
        tm->tm_mon = (tm1->tm_mon - tm2->tm_mon);
        tm->tm_year = (tm1->tm_year - tm2->tm_year);

        /* flip sign if necessary... */
        if (dt1 < dt2)
        {
            fsec = -fsec;
            tm->tm_sec = -tm->tm_sec;
            tm->tm_min = -tm->tm_min;
            tm->tm_hour = -tm->tm_hour;
            tm->tm_mday = -tm->tm_mday;
            tm->tm_mon = -tm->tm_mon;
            tm->tm_year = -tm->tm_year;
        }

        if (tm->tm_sec < 0)
        {
            tm->tm_sec += 60;
            tm->tm_min--;
        }

        if (tm->tm_min < 0)
        {
            tm->tm_min += 60;
            tm->tm_hour--;
        }

        if (tm->tm_hour < 0)
        {
            tm->tm_hour += 24;
            tm->tm_mday--;
        }

        if (tm->tm_mday < 0)
        {
            if (dt1 < dt2)
            {
                tm->tm_mday += day_tab[isleap(tm1->tm_year)][tm1->tm_mon - 1];
                tm->tm_mon--;
            }
            else
            {
                tm->tm_mday += day_tab[isleap(tm2->tm_year)][tm2->tm_mon - 1];
                tm->tm_mon--;
            }
        }

        if (tm->tm_mon < 0)
        {
            tm->tm_mon += 12;
            tm->tm_year--;
        }

        /* recover sign if necessary... */
        if (dt1 < dt2)
        {
            fsec = -fsec;
            tm->tm_sec = -tm->tm_sec;
            tm->tm_min = -tm->tm_min;
            tm->tm_hour = -tm->tm_hour;
            tm->tm_mday = -tm->tm_mday;
            tm->tm_mon = -tm->tm_mon;
            tm->tm_year = -tm->tm_year;
        }

        if (tm2interval(tm, fsec, result) != 0)
            elog(ERROR, "Unable to decode TIMESTAMP");
    }
    else
        elog(ERROR, "Unable to decode TIMESTAMP");

    PG_RETURN_INTERVAL_P(result);
}


/*----------------------------------------------------------
 *    Conversion operators.
 *---------------------------------------------------------*/


/* timestamp_text()
 * Convert timestamp to text data type.
 */
Datum
timestamp_text(PG_FUNCTION_ARGS)
{
    /* Input is a Timestamp, but may as well leave it in Datum form */
    Datum        timestamp = PG_GETARG_DATUM(0);
    text       *result;
    char       *str;
    int            len;

    str = DatumGetCString(DirectFunctionCall1(timestamp_out, timestamp));

    len = (strlen(str) + VARHDRSZ);

    result = palloc(len);

    VARATT_SIZEP(result) = len;
    memmove(VARDATA(result), str, (len - VARHDRSZ));

    pfree(str);

    PG_RETURN_TEXT_P(result);
}


/* text_timestamp()
 * Convert text string to timestamp.
 * Text type is not null terminated, so use temporary string
 *    then call the standard input routine.
 */
Datum
text_timestamp(PG_FUNCTION_ARGS)
{
    text       *str = PG_GETARG_TEXT_P(0);
    int            i;
    char       *sp,
               *dp,
                dstr[MAXDATELEN + 1];

    if (VARSIZE(str) - VARHDRSZ > MAXDATELEN)
        elog(ERROR, "TIMESTAMP bad external representation (too long)");

    sp = VARDATA(str);
    dp = dstr;
    for (i = 0; i < (VARSIZE(str) - VARHDRSZ); i++)
        *dp++ = *sp++;
    *dp = '\0';

    return DirectFunctionCall3(timestamp_in,
                               CStringGetDatum(dstr),
                               ObjectIdGetDatum(InvalidOid),
                               Int32GetDatum(-1));
}


/* timestamptz_text()
 * Convert timestamp with time zone to text data type.
 */
Datum
timestamptz_text(PG_FUNCTION_ARGS)
{
    /* Input is a Timestamp, but may as well leave it in Datum form */
    Datum        timestamp = PG_GETARG_DATUM(0);
    text       *result;
    char       *str;
    int            len;

    str = DatumGetCString(DirectFunctionCall1(timestamptz_out, timestamp));

    len = (strlen(str) + VARHDRSZ);

    result = palloc(len);

    VARATT_SIZEP(result) = len;
    memmove(VARDATA(result), str, (len - VARHDRSZ));

    pfree(str);

    PG_RETURN_TEXT_P(result);
}

/* text_timestamptz()
 * Convert text string to timestamp with time zone.
 * Text type is not null terminated, so use temporary string
 *    then call the standard input routine.
 */
Datum
text_timestamptz(PG_FUNCTION_ARGS)
{
    text       *str = PG_GETARG_TEXT_P(0);
    int            i;
    char       *sp,
               *dp,
                dstr[MAXDATELEN + 1];

    if (VARSIZE(str) - VARHDRSZ > MAXDATELEN)
        elog(ERROR, "TIMESTAMP WITH TIME ZONE bad external representation (too long)");

    sp = VARDATA(str);
    dp = dstr;
    for (i = 0; i < (VARSIZE(str) - VARHDRSZ); i++)
        *dp++ = *sp++;
    *dp = '\0';

    return DirectFunctionCall3(timestamptz_in,
                               CStringGetDatum(dstr),
                               ObjectIdGetDatum(InvalidOid),
                               Int32GetDatum(-1));
}


/* interval_text()
 * Convert interval to text data type.
 */
Datum
interval_text(PG_FUNCTION_ARGS)
{
    Interval   *interval = PG_GETARG_INTERVAL_P(0);
    text       *result;
    char       *str;
    int            len;

    str = DatumGetCString(DirectFunctionCall1(interval_out,
                                           IntervalPGetDatum(interval)));

    len = (strlen(str) + VARHDRSZ);

    result = palloc(len);

    VARATT_SIZEP(result) = len;
    memmove(VARDATA(result), str, (len - VARHDRSZ));

    pfree(str);

    PG_RETURN_TEXT_P(result);
}


/* text_interval()
 * Convert text string to interval.
 * Text type may not be null terminated, so copy to temporary string
 *    then call the standard input routine.
 */
Datum
text_interval(PG_FUNCTION_ARGS)
{
    text       *str = PG_GETARG_TEXT_P(0);
    int            i;
    char       *sp,
               *dp,
                dstr[MAXDATELEN + 1];

    if (VARSIZE(str) - VARHDRSZ > MAXDATELEN)
        elog(ERROR, "INTERVAL bad external representation (too long)");
    sp = VARDATA(str);
    dp = dstr;
    for (i = 0; i < (VARSIZE(str) - VARHDRSZ); i++)
        *dp++ = *sp++;
    *dp = '\0';

    return DirectFunctionCall3(interval_in,
                               CStringGetDatum(dstr),
                               ObjectIdGetDatum(InvalidOid),
                               Int32GetDatum(-1));
}

/* timestamp_trunc()
 * Truncate timestamp to specified units.
 */
Datum
timestamp_trunc(PG_FUNCTION_ARGS)
{
    text       *units = PG_GETARG_TEXT_P(0);
    Timestamp    timestamp = PG_GETARG_TIMESTAMP(1);
    Timestamp    result;
    int            type,
                val;
    int            i;
    char       *up,
               *lp,
                lowunits[MAXDATELEN + 1];
    double        fsec;
    struct tm    tt,
               *tm = &tt;

    if (VARSIZE(units) - VARHDRSZ > MAXDATELEN)
        elog(ERROR, "TIMESTAMP units '%s' not recognized",
             DatumGetCString(DirectFunctionCall1(textout,
                                               PointerGetDatum(units))));
    up = VARDATA(units);
    lp = lowunits;
    for (i = 0; i < (VARSIZE(units) - VARHDRSZ); i++)
        *lp++ = tolower((unsigned char) *up++);
    *lp = '\0';

    type = DecodeUnits(0, lowunits, &val);

    if (TIMESTAMP_NOT_FINITE(timestamp))
        PG_RETURN_TIMESTAMP(timestamp);

    if ((type == UNITS) && (timestamp2tm(timestamp, NULL, tm, &fsec, NULL) == 0))
    {
        switch (val)
        {
            case DTK_MILLENNIUM:
                tm->tm_year = (tm->tm_year / 1000) * 1000;
            case DTK_CENTURY:
                tm->tm_year = (tm->tm_year / 100) * 100;
            case DTK_DECADE:
                tm->tm_year = (tm->tm_year / 10) * 10;
            case DTK_YEAR:
                tm->tm_mon = 1;
            case DTK_QUARTER:
                tm->tm_mon = (3 * (tm->tm_mon / 4)) + 1;
            case DTK_MONTH:
                tm->tm_mday = 1;
            case DTK_DAY:
                tm->tm_hour = 0;
            case DTK_HOUR:
                tm->tm_min = 0;
            case DTK_MINUTE:
                tm->tm_sec = 0;
            case DTK_SECOND:
                fsec = 0;
                break;

            case DTK_MILLISEC:
                fsec = rint(fsec * 1000) / 1000;
                break;

            case DTK_MICROSEC:
                fsec = rint(fsec * 1000000) / 1000000;
                break;

            default:
                elog(ERROR, "TIMESTAMP units '%s' not supported", lowunits);
                result = 0;
        }

        if (tm2timestamp(tm, fsec, NULL, &result) != 0)
            elog(ERROR, "Unable to truncate TIMESTAMP to '%s'", lowunits);
    }
    else
    {
        elog(ERROR, "TIMESTAMP units '%s' not recognized", lowunits);
        result = 0;
    }

    PG_RETURN_TIMESTAMP(result);
}

/* timestamptz_trunc()
 * Truncate timestamp to specified units.
 */
Datum
timestamptz_trunc(PG_FUNCTION_ARGS)
{
    text       *units = PG_GETARG_TEXT_P(0);
    TimestampTz timestamp = PG_GETARG_TIMESTAMP(1);
    TimestampTz result;
    int            tz;
    int            type,
                val;
    int            i;
    char       *up,
               *lp,
                lowunits[MAXDATELEN + 1];
    double        fsec;
    char       *tzn;
    struct tm    tt,
               *tm = &tt;

    if (VARSIZE(units) - VARHDRSZ > MAXDATELEN)
        elog(ERROR, "TIMESTAMP WITH TIME ZONE units '%s' not recognized",
             DatumGetCString(DirectFunctionCall1(textout,
                                               PointerGetDatum(units))));
    up = VARDATA(units);
    lp = lowunits;
    for (i = 0; i < (VARSIZE(units) - VARHDRSZ); i++)
        *lp++ = tolower((unsigned char) *up++);
    *lp = '\0';

    type = DecodeUnits(0, lowunits, &val);

    if (TIMESTAMP_NOT_FINITE(timestamp))
        PG_RETURN_TIMESTAMPTZ(timestamp);

    if ((type == UNITS) && (timestamp2tm(timestamp, &tz, tm, &fsec, &tzn) == 0))
    {
        switch (val)
        {
            case DTK_MILLENNIUM:
                tm->tm_year = (tm->tm_year / 1000) * 1000;
            case DTK_CENTURY:
                tm->tm_year = (tm->tm_year / 100) * 100;
            case DTK_DECADE:
                tm->tm_year = (tm->tm_year / 10) * 10;
            case DTK_YEAR:
                tm->tm_mon = 1;
            case DTK_QUARTER:
                tm->tm_mon = (3 * (tm->tm_mon / 4)) + 1;
            case DTK_MONTH:
                tm->tm_mday = 1;
            case DTK_DAY:
                tm->tm_hour = 0;
            case DTK_HOUR:
                tm->tm_min = 0;
            case DTK_MINUTE:
                tm->tm_sec = 0;
            case DTK_SECOND:
                fsec = 0;
                break;

            case DTK_MILLISEC:
                fsec = rint(fsec * 1000) / 1000;
                break;
            case DTK_MICROSEC:
                fsec = rint(fsec * 1000000) / 1000000;
                break;

            default:
                elog(ERROR, "TIMESTAMP WITH TIME ZONE units '%s' not supported", lowunits);
                result = 0;
        }

        tz = DetermineLocalTimeZone(tm);

        if (tm2timestamp(tm, fsec, &tz, &result) != 0)
            elog(ERROR, "Unable to truncate TIMESTAMP WITH TIME ZONE to '%s'", lowunits);
    }
    else
    {
        elog(ERROR, "TIMESTAMP WITH TIME ZONE units '%s' not recognized", lowunits);
        PG_RETURN_NULL();
    }

    PG_RETURN_TIMESTAMPTZ(result);
}

/* interval_trunc()
 * Extract specified field from interval.
 */
Datum
interval_trunc(PG_FUNCTION_ARGS)
{
    text       *units = PG_GETARG_TEXT_P(0);
    Interval   *interval = PG_GETARG_INTERVAL_P(1);
    Interval   *result;
    int            type,
                val;
    int            i;
    char       *up,
               *lp,
                lowunits[MAXDATELEN + 1];
    double        fsec;
    struct tm    tt,
               *tm = &tt;

    result = (Interval *) palloc(sizeof(Interval));

    if (VARSIZE(units) - VARHDRSZ > MAXDATELEN)
        elog(ERROR, "INTERVAL units '%s' not recognized",
             DatumGetCString(DirectFunctionCall1(textout,
                                               PointerGetDatum(units))));
    up = VARDATA(units);
    lp = lowunits;
    for (i = 0; i < (VARSIZE(units) - VARHDRSZ); i++)
        *lp++ = tolower((unsigned char) *up++);
    *lp = '\0';

    type = DecodeUnits(0, lowunits, &val);

    if (type == UNITS)
    {
        if (interval2tm(*interval, tm, &fsec) == 0)
        {
            switch (val)
            {
                case DTK_MILLENNIUM:
                    tm->tm_year = (tm->tm_year / 1000) * 1000;
                case DTK_CENTURY:
                    tm->tm_year = (tm->tm_year / 100) * 100;
                case DTK_DECADE:
                    tm->tm_year = (tm->tm_year / 10) * 10;
                case DTK_YEAR:
                    tm->tm_mon = 0;
                case DTK_QUARTER:
                    tm->tm_mon = (3 * (tm->tm_mon / 4));
                case DTK_MONTH:
                    tm->tm_mday = 0;
                case DTK_DAY:
                    tm->tm_hour = 0;
                case DTK_HOUR:
                    tm->tm_min = 0;
                case DTK_MINUTE:
                    tm->tm_sec = 0;
                case DTK_SECOND:
                    fsec = 0;
                    break;

                case DTK_MILLISEC:
                    fsec = rint(fsec * 1000) / 1000;
                    break;

                case DTK_MICROSEC:
                    fsec = rint(fsec * 1000000) / 1000000;
                    break;

                default:
                    elog(ERROR, "INTERVAL units '%s' not supported", lowunits);
            }

            if (tm2interval(tm, fsec, result) != 0)
                elog(ERROR, "Unable to truncate INTERVAL to '%s'", lowunits);

        }
        else
        {
            elog(NOTICE, "Unable to decode INTERVAL; internal coding error");
            *result = *interval;
        }
    }
    else
    {
        elog(ERROR, "INTERVAL units '%s' not recognized",
             DatumGetCString(DirectFunctionCall1(textout,
                                               PointerGetDatum(units))));
        *result = *interval;
    }

    PG_RETURN_INTERVAL_P(result);
}

/* isoweek2date()
 * Convert ISO week of year number to date.
 * The year field must be specified!
 * karel 2000/08/07
 */
void
isoweek2date(int woy, int *year, int *mon, int *mday)
{
    int            day0,
                day4,
                dayn;

    if (!*year)
        elog(ERROR, "isoweek2date(): can't convert without year information");

    /* fourth day of current year */
    day4 = date2j(*year, 1, 4);

    /* day0 == offset to first day of week (Monday) */
    day0 = (j2day(day4 - 1) % 7);

    dayn = ((woy - 1) * 7) + (day4 - day0);

    j2date(dayn, year, mon, mday);
}

/* date2isoweek()
 *
 *    Returns ISO week number of year.
 */
int
date2isoweek(int year, int mon, int mday)
{
    float8        result;
    int            day0,
                day4,
                dayn;

    /* current day */
    dayn = date2j(year, mon, mday);

    /* fourth day of current year */
    day4 = date2j(year, 1, 4);

    /* day0 == offset to first day of week (Monday) */
    day0 = (j2day(day4 - 1) % 7);

    /*
     * We need the first week containing a Thursday, otherwise this day
     * falls into the previous year for purposes of counting weeks
     */
    if (dayn < (day4 - day0))
    {
        day4 = date2j((year - 1), 1, 4);

        /* day0 == offset to first day of week (Monday) */
        day0 = (j2day(day4 - 1) % 7);
    }

    result = (((dayn - (day4 - day0)) / 7) + 1);

    /*
     * Sometimes the last few days in a year will fall into the first week
     * of the next year, so check for this.
     */
    if (result >= 53)
    {
        day4 = date2j((year + 1), 1, 4);

        /* day0 == offset to first day of week (Monday) */
        day0 = (j2day(day4 - 1) % 7);

        if (dayn >= (day4 - day0))
            result = (((dayn - (day4 - day0)) / 7) + 1);
    }

    return (int) result;
}


/* timestamp_part()
 * Extract specified field from timestamp.
 */
Datum
timestamp_part(PG_FUNCTION_ARGS)
{
    text       *units = PG_GETARG_TEXT_P(0);
    Timestamp    timestamp = PG_GETARG_TIMESTAMP(1);
    float8        result;
    int            type,
                val;
    int            i;
    char       *up,
               *lp,
                lowunits[MAXDATELEN + 1];
    double        fsec;
    struct tm    tt,
               *tm = &tt;

    if (VARSIZE(units) - VARHDRSZ > MAXDATELEN)
        elog(ERROR, "TIMESTAMP units '%s' not recognized",
             DatumGetCString(DirectFunctionCall1(textout,
                                               PointerGetDatum(units))));
    up = VARDATA(units);
    lp = lowunits;
    for (i = 0; i < (VARSIZE(units) - VARHDRSZ); i++)
        *lp++ = tolower((unsigned char) *up++);
    *lp = '\0';

    type = DecodeUnits(0, lowunits, &val);
    if (type == UNKNOWN_FIELD)
        type = DecodeSpecial(0, lowunits, &val);

    if (TIMESTAMP_NOT_FINITE(timestamp))
    {
        result = 0;
        PG_RETURN_FLOAT8(result);
    }

    if ((type == UNITS)
        && (timestamp2tm(timestamp, NULL, tm, &fsec, NULL) == 0))
    {
        switch (val)
        {
            case DTK_MICROSEC:
                result = (fsec * 1000000);
                break;

            case DTK_MILLISEC:
                result = (fsec * 1000);
                break;

            case DTK_SECOND:
                result = (tm->tm_sec + fsec);
                break;

            case DTK_MINUTE:
                result = tm->tm_min;
                break;

            case DTK_HOUR:
                result = tm->tm_hour;
                break;

            case DTK_DAY:
                result = tm->tm_mday;
                break;

            case DTK_MONTH:
                result = tm->tm_mon;
                break;

            case DTK_QUARTER:
                result = ((tm->tm_mon - 1) / 3) + 1;
                break;

            case DTK_WEEK:
                result = (float8) date2isoweek(tm->tm_year, tm->tm_mon, tm->tm_mday);
                break;

            case DTK_YEAR:
                result = tm->tm_year;
                break;

            case DTK_DECADE:
                result = (tm->tm_year / 10);
                break;

            case DTK_CENTURY:
                result = (tm->tm_year / 100);
                break;

            case DTK_MILLENNIUM:
                result = (tm->tm_year / 1000);
                break;

            case DTK_TZ:
            case DTK_TZ_MINUTE:
            case DTK_TZ_HOUR:
            default:
                elog(ERROR, "TIMESTAMP units '%s' not supported", lowunits);
                result = 0;
        }
    }
    else if (type == RESERV)
    {
        switch (val)
        {
            case DTK_EPOCH:
                result = timestamp - SetEpochTimestamp();
                break;

            case DTK_DOW:
                if (timestamp2tm(timestamp, NULL, tm, &fsec, NULL) != 0)
                    elog(ERROR, "Unable to encode TIMESTAMP");

                result = j2day(date2j(tm->tm_year, tm->tm_mon, tm->tm_mday));
                break;

            case DTK_DOY:
                if (timestamp2tm(timestamp, NULL, tm, &fsec, NULL) != 0)
                    elog(ERROR, "Unable to encode TIMESTAMP");

                result = (date2j(tm->tm_year, tm->tm_mon, tm->tm_mday)
                          - date2j(tm->tm_year, 1, 1) + 1);
                break;

            default:
                elog(ERROR, "TIMESTAMP units '%s' not supported", lowunits);
                result = 0;
        }

    }
    else
    {
        elog(ERROR, "TIMESTAMP units '%s' not recognized", lowunits);
        result = 0;
    }

    PG_RETURN_FLOAT8(result);
}

/* timestamptz_part()
 * Extract specified field from timestamp with time zone.
 */
Datum
timestamptz_part(PG_FUNCTION_ARGS)
{
    text       *units = PG_GETARG_TEXT_P(0);
    TimestampTz timestamp = PG_GETARG_TIMESTAMP(1);
    float8        result;
    int            tz;
    int            type,
                val;
    int            i;
    char       *up,
               *lp,
                lowunits[MAXDATELEN + 1];
    double        dummy;
    double        fsec;
    char       *tzn;
    struct tm    tt,
               *tm = &tt;

    if (VARSIZE(units) - VARHDRSZ > MAXDATELEN)
        elog(ERROR, "TIMESTAMP WITH TIME ZONE units '%s' not recognized",
             DatumGetCString(DirectFunctionCall1(textout,
                                               PointerGetDatum(units))));
    up = VARDATA(units);
    lp = lowunits;
    for (i = 0; i < (VARSIZE(units) - VARHDRSZ); i++)
        *lp++ = tolower((unsigned char) *up++);
    *lp = '\0';

    type = DecodeUnits(0, lowunits, &val);
    if (type == UNKNOWN_FIELD)
        type = DecodeSpecial(0, lowunits, &val);

    if (TIMESTAMP_NOT_FINITE(timestamp))
    {
        result = 0;
        PG_RETURN_FLOAT8(result);
    }

    if ((type == UNITS) && (timestamp2tm(timestamp, &tz, tm, &fsec, &tzn) == 0))
    {
        switch (val)
        {
            case DTK_TZ:
                result = tz;
                break;

            case DTK_TZ_MINUTE:
                result = tz / 60;
                TMODULO(result, dummy, 60e0);
                break;

            case DTK_TZ_HOUR:
                dummy = tz;
                TMODULO(dummy, result, 3600e0);
                break;

            case DTK_MICROSEC:
                result = (fsec * 1000000);
                break;

            case DTK_MILLISEC:
                result = (fsec * 1000);
                break;

            case DTK_SECOND:
                result = (tm->tm_sec + fsec);
                break;

            case DTK_MINUTE:
                result = tm->tm_min;
                break;

            case DTK_HOUR:
                result = tm->tm_hour;
                break;

            case DTK_DAY:
                result = tm->tm_mday;
                break;

            case DTK_MONTH:
                result = tm->tm_mon;
                break;

            case DTK_QUARTER:
                result = ((tm->tm_mon - 1) / 3) + 1;
                break;

            case DTK_WEEK:
                result = (float8) date2isoweek(tm->tm_year, tm->tm_mon, tm->tm_mday);
                break;

            case DTK_YEAR:
                result = tm->tm_year;
                break;

            case DTK_DECADE:
                result = (tm->tm_year / 10);
                break;

            case DTK_CENTURY:
                result = (tm->tm_year / 100);
                break;

            case DTK_MILLENNIUM:
                result = (tm->tm_year / 1000);
                break;

            default:
                elog(ERROR, "TIMESTAMP WITH TIME ZONE units '%s' not supported", lowunits);
                result = 0;
        }

    }
    else if (type == RESERV)
    {
        switch (val)
        {
            case DTK_EPOCH:
                result = timestamp - SetEpochTimestamp();
                break;

            case DTK_DOW:
                if (timestamp2tm(timestamp, &tz, tm, &fsec, &tzn) != 0)
                    elog(ERROR, "Unable to encode TIMESTAMP WITH TIME ZONE");

                result = j2day(date2j(tm->tm_year, tm->tm_mon, tm->tm_mday));
                break;

            case DTK_DOY:
                if (timestamp2tm(timestamp, &tz, tm, &fsec, &tzn) != 0)
                    elog(ERROR, "Unable to encode TIMESTAMP WITH TIME ZONE");

                result = (date2j(tm->tm_year, tm->tm_mon, tm->tm_mday)
                          - date2j(tm->tm_year, 1, 1) + 1);
                break;

            default:
                elog(ERROR, "TIMESTAMP WITH TIME ZONE units '%s' not supported", lowunits);
                result = 0;
        }
    }
    else
    {
        elog(ERROR, "TIMESTAMP WITH TIME ZONE units '%s' not recognized", lowunits);
        result = 0;
    }

    PG_RETURN_FLOAT8(result);
}


/* interval_part()
 * Extract specified field from interval.
 */
Datum
interval_part(PG_FUNCTION_ARGS)
{
    text       *units = PG_GETARG_TEXT_P(0);
    Interval   *interval = PG_GETARG_INTERVAL_P(1);
    float8        result;
    int            type,
                val;
    int            i;
    char       *up,
               *lp,
                lowunits[MAXDATELEN + 1];
    double        fsec;
    struct tm    tt,
               *tm = &tt;

    if (VARSIZE(units) - VARHDRSZ > MAXDATELEN)
        elog(ERROR, "INTERVAL units '%s' not recognized",
             DatumGetCString(DirectFunctionCall1(textout,
                                               PointerGetDatum(units))));
    up = VARDATA(units);
    lp = lowunits;
    for (i = 0; i < (VARSIZE(units) - VARHDRSZ); i++)
        *lp++ = tolower((unsigned char) *up++);
    *lp = '\0';

    type = DecodeUnits(0, lowunits, &val);
    if (type == UNKNOWN_FIELD)
        type = DecodeSpecial(0, lowunits, &val);

    if (type == UNITS)
    {
        if (interval2tm(*interval, tm, &fsec) == 0)
        {
            switch (val)
            {
                case DTK_MICROSEC:
                    result = ((tm->tm_sec + fsec) * 1000000);
                    break;

                case DTK_MILLISEC:
                    result = ((tm->tm_sec + fsec) * 1000);
                    break;

                case DTK_SECOND:
                    result = (tm->tm_sec + fsec);
                    break;

                case DTK_MINUTE:
                    result = tm->tm_min;
                    break;

                case DTK_HOUR:
                    result = tm->tm_hour;
                    break;

                case DTK_DAY:
                    result = tm->tm_mday;
                    break;

                case DTK_MONTH:
                    result = tm->tm_mon;
                    break;

                case DTK_QUARTER:
                    result = (tm->tm_mon / 4) + 1;
                    break;

                case DTK_YEAR:
                    result = tm->tm_year;
                    break;

                case DTK_DECADE:
                    result = (tm->tm_year / 10);
                    break;

                case DTK_CENTURY:
                    result = (tm->tm_year / 100);
                    break;

                case DTK_MILLENNIUM:
                    result = (tm->tm_year / 1000);
                    break;

                default:
                    elog(ERROR, "INTERVAL units '%s' not supported",
                         DatumGetCString(DirectFunctionCall1(textout,
                                               PointerGetDatum(units))));
                    result = 0;
            }

        }
        else
        {
            elog(NOTICE, "Unable to decode INTERVAL"
                 "\n\tinterval_part() internal coding error");
            result = 0;
        }
    }
    else if ((type == RESERV) && (val == DTK_EPOCH))
    {
        result = interval->time;
        if (interval->month != 0)
        {
            result += ((365.25 * 86400) * (interval->month / 12));
            result += ((30 * 86400) * (interval->month % 12));
        }
    }
    else
    {
        elog(ERROR, "INTERVAL units '%s' not recognized",
             DatumGetCString(DirectFunctionCall1(textout,
                                               PointerGetDatum(units))));
        result = 0;
    }

    PG_RETURN_FLOAT8(result);
}


/* timestamp_zone()
 * Encode timestamp type with specified time zone.
 */
Datum
timestamp_zone(PG_FUNCTION_ARGS)
{
    text       *zone = PG_GETARG_TEXT_P(0);
    Timestamp    timestamp = PG_GETARG_TIMESTAMP(1);
    TimestampTz result;
    int            tz;
    int            type,
                val;
    int            i;
    char       *up,
               *lp,
                lowzone[MAXDATELEN + 1];

    if (VARSIZE(zone) - VARHDRSZ > MAXDATELEN)
        elog(ERROR, "Time zone '%s' not recognized",
             DatumGetCString(DirectFunctionCall1(textout,
                                                 PointerGetDatum(zone))));

    if (TIMESTAMP_NOT_FINITE(timestamp))
        PG_RETURN_TIMESTAMPTZ(timestamp);

    up = VARDATA(zone);
    lp = lowzone;
    for (i = 0; i < (VARSIZE(zone) - VARHDRSZ); i++)
        *lp++ = tolower((unsigned char) *up++);
    *lp = '\0';

    type = DecodeSpecial(0, lowzone, &val);

    if ((type == TZ) || (type == DTZ))
    {
        tz = val * 60;
        result = timestamp - tz;
    }
    else
    {
        elog(ERROR, "Time zone '%s' not recognized", lowzone);
        PG_RETURN_NULL();
    }

    PG_RETURN_TIMESTAMPTZ(result);
}    /* timestamp_zone() */

/* timestamp_izone()
 * Encode timestamp type with specified time interval as time zone.
 * Require ISO-formatted result, since character-string time zone is not available.
 */
Datum
timestamp_izone(PG_FUNCTION_ARGS)
{
    Interval   *zone = PG_GETARG_INTERVAL_P(0);
    Timestamp    timestamp = PG_GETARG_TIMESTAMP(1);
    TimestampTz result;
    int            tz;

    if (TIMESTAMP_NOT_FINITE(timestamp))
        PG_RETURN_TIMESTAMPTZ(timestamp);

    if (zone->month != 0)
        elog(ERROR, "INTERVAL time zone '%s' not legal (month specified)",
             DatumGetCString(DirectFunctionCall1(interval_out,
                                                 PointerGetDatum(zone))));

    tz = -(zone->time);
    result = timestamp - tz;

    PG_RETURN_TIMESTAMPTZ(result);
}    /* timestamp_izone() */

/* timestamp_timestamptz()
 * Convert local timestamp to timestamp at GMT
 */
Datum
timestamp_timestamptz(PG_FUNCTION_ARGS)
{
    Timestamp    timestamp = PG_GETARG_TIMESTAMP(0);
    TimestampTz result;
    struct tm    tt,
               *tm = &tt;
    double        fsec;
    int            tz;

    if (TIMESTAMP_NOT_FINITE(timestamp))
        result = timestamp;
    else
    {
        if (timestamp2tm(timestamp, NULL, tm, &fsec, NULL) != 0)
            elog(ERROR, "Unable to convert TIMESTAMP to TIMESTAMP WITH TIME ZONE (tm)");

        tz = DetermineLocalTimeZone(tm);

        if (tm2timestamp(tm, fsec, &tz, &result) != 0)
            elog(ERROR, "Unable to convert TIMESTAMP to TIMESTAMP WITH TIME ZONE");
    }

    PG_RETURN_TIMESTAMPTZ(result);
}

/* timestamptz_timestamp()
 * Convert timestamp at GMT to local timestamp
 */
Datum
timestamptz_timestamp(PG_FUNCTION_ARGS)
{
    TimestampTz timestamp = PG_GETARG_TIMESTAMP(0);
    Timestamp    result;
    struct tm    tt,
               *tm = &tt;
    double        fsec;
    char       *tzn;
    int            tz;

    if (TIMESTAMP_NOT_FINITE(timestamp))
        result = timestamp;
    else
    {
        if (timestamp2tm(timestamp, &tz, tm, &fsec, &tzn) != 0)
            elog(ERROR, "Unable to convert TIMESTAMP WITH TIME ZONE to TIMESTAMP (tm)");

        if (tm2timestamp(tm, fsec, NULL, &result) != 0)
            elog(ERROR, "Unable to convert TIMESTAMP WITH TIME ZONE to TIMESTAMP");
    }

    PG_RETURN_TIMESTAMP(result);
}

/* timestamptz_zone()
 * Encode timestamp with time zone type with specified time zone.
 */
Datum
timestamptz_zone(PG_FUNCTION_ARGS)
{
    text       *zone = PG_GETARG_TEXT_P(0);
    TimestampTz timestamp = PG_GETARG_TIMESTAMP(1);
    text       *result;
    TimestampTz dt;
    int            tz;
    int            type,
                val;
    int            i;
    char       *up,
               *lp,
                lowzone[MAXDATELEN + 1];
    char       *tzn,
                upzone[MAXDATELEN + 1];
    double        fsec;
    struct tm    tt,
               *tm = &tt;
    char        buf[MAXDATELEN + 1];
    int            len;

    if (VARSIZE(zone) - VARHDRSZ > MAXDATELEN)
        elog(ERROR, "Time zone '%s' not recognized",
             DatumGetCString(DirectFunctionCall1(textout,
                                                 PointerGetDatum(zone))));
    up = VARDATA(zone);
    lp = lowzone;
    for (i = 0; i < (VARSIZE(zone) - VARHDRSZ); i++)
        *lp++ = tolower((unsigned char) *up++);
    *lp = '\0';

    type = DecodeSpecial(0, lowzone, &val);

    if (TIMESTAMP_NOT_FINITE(timestamp))
        PG_RETURN_TEXT_P(pstrdup(""));

    if ((type == TZ) || (type == DTZ))
    {
        tm->tm_isdst = ((type == DTZ) ? 1 : 0);
        tz = val * 60;

        dt = dt2local(timestamp, tz);

        if (timestamp2tm(dt, NULL, tm, &fsec, NULL) != 0)
            elog(ERROR, "Unable to decode TIMESTAMP WITH TIME ZONE"
                 "\n\ttimestamptz_zone() internal coding error");

        up = upzone;
        lp = lowzone;
        for (i = 0; *lp != '\0'; i++)
            *up++ = toupper((unsigned char) *lp++);
        *up = '\0';

        tzn = upzone;
        EncodeDateTime(tm, fsec, &tz, &tzn, DateStyle, buf);

        len = (strlen(buf) + VARHDRSZ);

        result = palloc(len);

        VARATT_SIZEP(result) = len;
        memmove(VARDATA(result), buf, (len - VARHDRSZ));
    }
    else
    {
        elog(ERROR, "Time zone '%s' not recognized", lowzone);
        PG_RETURN_TEXT_P(pstrdup(""));
    }

    PG_RETURN_TEXT_P(result);
}    /* timestamptz_zone() */

/* timestamptz_izone()
 * Encode timestamp with time zone type with specified time interval as time zone.
 * Require ISO-formatted result, since character-string time zone is not available.
 */
Datum
timestamptz_izone(PG_FUNCTION_ARGS)
{
    Interval   *zone = PG_GETARG_INTERVAL_P(0);
    TimestampTz timestamp = PG_GETARG_TIMESTAMP(1);
    text       *result;
    TimestampTz dt;
    int            tz;
    char       *tzn = "";
    double        fsec;
    struct tm    tt,
               *tm = &tt;
    char        buf[MAXDATELEN + 1];
    int            len;

    if (TIMESTAMP_NOT_FINITE(timestamp))
        PG_RETURN_TEXT_P(pstrdup(""));

    if (zone->month != 0)
        elog(ERROR, "INTERVAL time zone '%s' not legal (month specified)",
             DatumGetCString(DirectFunctionCall1(interval_out,
                                                 PointerGetDatum(zone))));

    tm->tm_isdst = -1;
    tz = -(zone->time);

    dt = dt2local(timestamp, tz);

    if (timestamp2tm(dt, NULL, tm, &fsec, NULL) != 0)
        elog(ERROR, "Unable to decode TIMESTAMP WITH TIME ZONE"
             "\n\ttimestamptz_izone() internal coding error");

    EncodeDateTime(tm, fsec, &tz, &tzn, USE_ISO_DATES, buf);
    len = (strlen(buf) + VARHDRSZ);

    result = palloc(len);
    VARATT_SIZEP(result) = len;
    memmove(VARDATA(result), buf, (len - VARHDRSZ));

    PG_RETURN_TEXT_P(result);
}    /* timestamptz_izone() */