nabstime.c

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/*-------------------------------------------------------------------------
 *
 * nabstime.c
 *    Utilities for the built-in type "AbsoluteTime".
 *    Functions for the built-in type "RelativeTime".
 *    Functions for the built-in type "TimeInterval".
 *
 * Portions Copyright (c) 1996-2013, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *    src/backend/utils/adt/nabstime.c
 *
 *-------------------------------------------------------------------------
 */
#include "postgres.h"

#include <ctype.h>
#include <float.h>
#include <limits.h>
#include <time.h>
#include <sys/time.h>

#include "libpq/pqformat.h"
#include "miscadmin.h"
#include "utils/builtins.h"
#include "utils/datetime.h"
#include "utils/nabstime.h"

#define MIN_DAYNUM (-24856)     /* December 13, 1901 */
#define MAX_DAYNUM 24854        /* January 18, 2038 */

/*
 * Unix epoch is Jan  1 00:00:00 1970.
 * Postgres knows about times sixty-eight years on either side of that
 * for these 4-byte types.
 *
 * "tinterval" is two 4-byte fields.
 * Definitions for parsing tinterval.
 */

#define IsSpace(C)              ((C) == ' ')

#define T_INTERVAL_INVAL   0    /* data represents no valid tinterval */
#define T_INTERVAL_VALID   1    /* data represents a valid tinterval */
/*
 * ['Mon May 10 23:59:12 1943 PST' 'Sun Jan 14 03:14:21 1973 PST']
 * 0        1         2         3         4         5         6
 * 1234567890123456789012345678901234567890123456789012345678901234
 *
 * we allocate some extra -- timezones are usually 3 characters but
 * this is not in the POSIX standard...
 */
#define T_INTERVAL_LEN                  80
#define INVALID_INTERVAL_STR            "Undefined Range"
#define INVALID_INTERVAL_STR_LEN        (sizeof(INVALID_INTERVAL_STR)-1)

#define ABSTIMEMIN(t1, t2) \
    (DatumGetBool(DirectFunctionCall2(abstimele, \
                  AbsoluteTimeGetDatum(t1), \
                  AbsoluteTimeGetDatum(t2))) ? (t1) : (t2))
#define ABSTIMEMAX(t1, t2) \
    (DatumGetBool(DirectFunctionCall2(abstimelt, \
                  AbsoluteTimeGetDatum(t1), \
                  AbsoluteTimeGetDatum(t2))) ? (t2) : (t1))


/*
 * Function prototypes -- internal to this file only
 */

static AbsoluteTime tm2abstime(struct pg_tm * tm, int tz);
static void reltime2tm(RelativeTime time, struct pg_tm * tm);
static void parsetinterval(char *i_string,
               AbsoluteTime *i_start,
               AbsoluteTime *i_end);


/*
 * GetCurrentAbsoluteTime()
 *
 * Get the current system time (relative to Unix epoch).
 *
 * NB: this will overflow in 2038; it should be gone long before that.
 */
AbsoluteTime
GetCurrentAbsoluteTime(void)
{
    time_t      now;

    now = time(NULL);
    return (AbsoluteTime) now;
}


void
abstime2tm(AbsoluteTime _time, int *tzp, struct pg_tm * tm, char **tzn)
{
    pg_time_t   time = (pg_time_t) _time;
    struct pg_tm *tx;

    /*
     * 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))
        time -= CTimeZone;

    if (!HasCTZSet && tzp != NULL)
        tx = pg_localtime(&time, session_timezone);
    else
        tx = pg_gmtime(&time);

    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;
    tm->tm_sec = tx->tm_sec;
    tm->tm_isdst = tx->tm_isdst;

    tm->tm_gmtoff = tx->tm_gmtoff;
    tm->tm_zone = tx->tm_zone;

    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_gmtoff = CTimeZone;
            tm->tm_isdst = 0;
            tm->tm_zone = NULL;
            if (tzn != NULL)
                *tzn = NULL;
        }
        else
        {
            *tzp = -tm->tm_gmtoff;      /* tm_gmtoff is Sun/DEC-ism */

            /*
             * XXX FreeBSD man pages indicate that this should work - tgl
             * 97/04/23
             */
            if (tzn != NULL)
            {
                /*
                 * Copy no more than MAXTZLEN bytes of timezone to tzn, in
                 * case it contains an error message, which doesn't fit in the
                 * buffer
                 */
                StrNCpy(*tzn, tm->tm_zone, MAXTZLEN + 1);
                if (strlen(tm->tm_zone) > MAXTZLEN)
                    ereport(WARNING,
                            (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
                             errmsg("invalid time zone name: \"%s\"",
                                    tm->tm_zone)));
            }
        }
    }
    else
        tm->tm_isdst = -1;
}


/* tm2abstime()
 * Convert a tm structure to abstime.
 * Note that tm has full year (not 1900-based) and 1-based month.
 */
static AbsoluteTime
tm2abstime(struct pg_tm * tm, int tz)
{
    int         day;
    AbsoluteTime sec;

    /* validate, before going out of range on some members */
    if (tm->tm_year < 1901 || tm->tm_year > 2038 ||
        tm->tm_mon < 1 || tm->tm_mon > MONTHS_PER_YEAR ||
        tm->tm_mday < 1 || tm->tm_mday > 31 ||
        tm->tm_hour < 0 ||
        tm->tm_hour > HOURS_PER_DAY ||  /* test for > 24:00:00 */
      (tm->tm_hour == HOURS_PER_DAY && (tm->tm_min > 0 || tm->tm_sec > 0)) ||
        tm->tm_min < 0 || tm->tm_min > MINS_PER_HOUR - 1 ||
        tm->tm_sec < 0 || tm->tm_sec > SECS_PER_MINUTE)
        return INVALID_ABSTIME;

    day = date2j(tm->tm_year, tm->tm_mon, tm->tm_mday) - UNIX_EPOCH_JDATE;

    /* check for time out of range */
    if (day < MIN_DAYNUM || day > MAX_DAYNUM)
        return INVALID_ABSTIME;

    /* convert to seconds */
    sec = tm->tm_sec + tz + (tm->tm_min + (day * HOURS_PER_DAY + tm->tm_hour) * MINS_PER_HOUR) * SECS_PER_MINUTE;

    /*
     * check for overflow.  We need a little slop here because the H/M/S plus
     * TZ offset could add up to more than 1 day.
     */
    if ((day >= MAX_DAYNUM - 10 && sec < 0) ||
        (day <= MIN_DAYNUM + 10 && sec > 0))
        return INVALID_ABSTIME;

    /* check for reserved values (e.g. "current" on edge of usual range */
    if (!AbsoluteTimeIsReal(sec))
        return INVALID_ABSTIME;

    return sec;
}


/* abstimein()
 * Decode date/time string and return abstime.
 */
Datum
abstimein(PG_FUNCTION_ARGS)
{
    char       *str = PG_GETARG_CSTRING(0);
    AbsoluteTime result;
    fsec_t      fsec;
    int         tz = 0;
    struct pg_tm date,
               *tm = &date;
    int         dterr;
    char       *field[MAXDATEFIELDS];
    char        workbuf[MAXDATELEN + 1];
    int         dtype;
    int         nf,
                ftype[MAXDATEFIELDS];

    dterr = ParseDateTime(str, workbuf, sizeof(workbuf),
                          field, ftype, MAXDATEFIELDS, &nf);
    if (dterr == 0)
        dterr = DecodeDateTime(field, ftype, nf, &dtype, tm, &fsec, &tz);
    if (dterr != 0)
        DateTimeParseError(dterr, str, "abstime");

    switch (dtype)
    {
        case DTK_DATE:
            result = tm2abstime(tm, tz);
            break;

        case DTK_EPOCH:

            /*
             * Don't bother retaining this as a reserved value, but instead
             * just set to the actual epoch time (1970-01-01)
             */
            result = 0;
            break;

        case DTK_LATE:
            result = NOEND_ABSTIME;
            break;

        case DTK_EARLY:
            result = NOSTART_ABSTIME;
            break;

        case DTK_INVALID:
            result = INVALID_ABSTIME;
            break;

        default:
            elog(ERROR, "unexpected dtype %d while parsing abstime \"%s\"",
                 dtype, str);
            result = INVALID_ABSTIME;
            break;
    };

    PG_RETURN_ABSOLUTETIME(result);
}


/* abstimeout()
 * Given an AbsoluteTime return the English text version of the date
 */
Datum
abstimeout(PG_FUNCTION_ARGS)
{
    AbsoluteTime time = PG_GETARG_ABSOLUTETIME(0);
    char       *result;
    int         tz;
    double      fsec = 0;
    struct pg_tm tt,
               *tm = &tt;
    char        buf[MAXDATELEN + 1];
    char        zone[MAXDATELEN + 1],
               *tzn = zone;

    switch (time)
    {
            /*
             * Note that timestamp no longer supports 'invalid'. Retain
             * 'invalid' for abstime for now, but dump it someday.
             */
        case INVALID_ABSTIME:
            strcpy(buf, INVALID);
            break;
        case NOEND_ABSTIME:
            strcpy(buf, LATE);
            break;
        case NOSTART_ABSTIME:
            strcpy(buf, EARLY);
            break;
        default:
            abstime2tm(time, &tz, tm, &tzn);
            EncodeDateTime(tm, fsec, true, tz, tzn, DateStyle, buf);
            break;
    }

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

/*
 *      abstimerecv         - converts external binary format to abstime
 */
Datum
abstimerecv(PG_FUNCTION_ARGS)
{
    StringInfo  buf = (StringInfo) PG_GETARG_POINTER(0);

    PG_RETURN_ABSOLUTETIME((AbsoluteTime) pq_getmsgint(buf, sizeof(AbsoluteTime)));
}

/*
 *      abstimesend         - converts abstime to binary format
 */
Datum
abstimesend(PG_FUNCTION_ARGS)
{
    AbsoluteTime time = PG_GETARG_ABSOLUTETIME(0);
    StringInfoData buf;

    pq_begintypsend(&buf);
    pq_sendint(&buf, time, sizeof(time));
    PG_RETURN_BYTEA_P(pq_endtypsend(&buf));
}


/* abstime_finite()
 */
Datum
abstime_finite(PG_FUNCTION_ARGS)
{
    AbsoluteTime abstime = PG_GETARG_ABSOLUTETIME(0);

    PG_RETURN_BOOL(abstime != INVALID_ABSTIME &&
                   abstime != NOSTART_ABSTIME &&
                   abstime != NOEND_ABSTIME);
}


/*
 * abstime comparison routines
 */
static int
abstime_cmp_internal(AbsoluteTime a, AbsoluteTime b)
{
    /*
     * We consider all INVALIDs to be equal and larger than any non-INVALID.
     * This is somewhat arbitrary; the important thing is to have a consistent
     * sort order.
     */
    if (a == INVALID_ABSTIME)
    {
        if (b == INVALID_ABSTIME)
            return 0;           /* INVALID = INVALID */
        else
            return 1;           /* INVALID > non-INVALID */
    }

    if (b == INVALID_ABSTIME)
        return -1;              /* non-INVALID < INVALID */

    if (a > b)
        return 1;
    else if (a == b)
        return 0;
    else
        return -1;
}

Datum
abstimeeq(PG_FUNCTION_ARGS)
{
    AbsoluteTime t1 = PG_GETARG_ABSOLUTETIME(0);
    AbsoluteTime t2 = PG_GETARG_ABSOLUTETIME(1);

    PG_RETURN_BOOL(abstime_cmp_internal(t1, t2) == 0);
}

Datum
abstimene(PG_FUNCTION_ARGS)
{
    AbsoluteTime t1 = PG_GETARG_ABSOLUTETIME(0);
    AbsoluteTime t2 = PG_GETARG_ABSOLUTETIME(1);

    PG_RETURN_BOOL(abstime_cmp_internal(t1, t2) != 0);
}

Datum
abstimelt(PG_FUNCTION_ARGS)
{
    AbsoluteTime t1 = PG_GETARG_ABSOLUTETIME(0);
    AbsoluteTime t2 = PG_GETARG_ABSOLUTETIME(1);

    PG_RETURN_BOOL(abstime_cmp_internal(t1, t2) < 0);
}

Datum
abstimegt(PG_FUNCTION_ARGS)
{
    AbsoluteTime t1 = PG_GETARG_ABSOLUTETIME(0);
    AbsoluteTime t2 = PG_GETARG_ABSOLUTETIME(1);

    PG_RETURN_BOOL(abstime_cmp_internal(t1, t2) > 0);
}

Datum
abstimele(PG_FUNCTION_ARGS)
{
    AbsoluteTime t1 = PG_GETARG_ABSOLUTETIME(0);
    AbsoluteTime t2 = PG_GETARG_ABSOLUTETIME(1);

    PG_RETURN_BOOL(abstime_cmp_internal(t1, t2) <= 0);
}

Datum
abstimege(PG_FUNCTION_ARGS)
{
    AbsoluteTime t1 = PG_GETARG_ABSOLUTETIME(0);
    AbsoluteTime t2 = PG_GETARG_ABSOLUTETIME(1);

    PG_RETURN_BOOL(abstime_cmp_internal(t1, t2) >= 0);
}

Datum
btabstimecmp(PG_FUNCTION_ARGS)
{
    AbsoluteTime t1 = PG_GETARG_ABSOLUTETIME(0);
    AbsoluteTime t2 = PG_GETARG_ABSOLUTETIME(1);

    PG_RETURN_INT32(abstime_cmp_internal(t1, t2));
}


/* timestamp_abstime()
 * Convert timestamp to abstime.
 */
Datum
timestamp_abstime(PG_FUNCTION_ARGS)
{
    Timestamp   timestamp = PG_GETARG_TIMESTAMP(0);
    AbsoluteTime result;
    fsec_t      fsec;
    int         tz;
    struct pg_tm tt,
               *tm = &tt;

    if (TIMESTAMP_IS_NOBEGIN(timestamp))
        result = NOSTART_ABSTIME;
    else if (TIMESTAMP_IS_NOEND(timestamp))
        result = NOEND_ABSTIME;
    else if (timestamp2tm(timestamp, NULL, tm, &fsec, NULL, NULL) == 0)
    {
        tz = DetermineTimeZoneOffset(tm, session_timezone);
        result = tm2abstime(tm, tz);
    }
    else
    {
        ereport(ERROR,
                (errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
                 errmsg("timestamp out of range")));
        result = INVALID_ABSTIME;
    }

    PG_RETURN_ABSOLUTETIME(result);
}

/* abstime_timestamp()
 * Convert abstime to timestamp.
 */
Datum
abstime_timestamp(PG_FUNCTION_ARGS)
{
    AbsoluteTime abstime = PG_GETARG_ABSOLUTETIME(0);
    Timestamp   result;
    struct pg_tm tt,
               *tm = &tt;
    int         tz;
    char        zone[MAXDATELEN + 1],
               *tzn = zone;

    switch (abstime)
    {
        case INVALID_ABSTIME:
            ereport(ERROR,
                    (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("cannot convert abstime \"invalid\" to timestamp")));
            TIMESTAMP_NOBEGIN(result);
            break;

        case NOSTART_ABSTIME:
            TIMESTAMP_NOBEGIN(result);
            break;

        case NOEND_ABSTIME:
            TIMESTAMP_NOEND(result);
            break;

        default:
            abstime2tm(abstime, &tz, tm, &tzn);
            if (tm2timestamp(tm, 0, NULL, &result) != 0)
                ereport(ERROR,
                        (errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
                         errmsg("timestamp out of range")));
            break;
    };

    PG_RETURN_TIMESTAMP(result);
}


/* timestamptz_abstime()
 * Convert timestamp with time zone to abstime.
 */
Datum
timestamptz_abstime(PG_FUNCTION_ARGS)
{
    TimestampTz timestamp = PG_GETARG_TIMESTAMP(0);
    AbsoluteTime result;
    fsec_t      fsec;
    struct pg_tm tt,
               *tm = &tt;

    if (TIMESTAMP_IS_NOBEGIN(timestamp))
        result = NOSTART_ABSTIME;
    else if (TIMESTAMP_IS_NOEND(timestamp))
        result = NOEND_ABSTIME;
    else if (timestamp2tm(timestamp, NULL, tm, &fsec, NULL, NULL) == 0)
        result = tm2abstime(tm, 0);
    else
    {
        ereport(ERROR,
                (errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
                 errmsg("timestamp out of range")));
        result = INVALID_ABSTIME;
    }

    PG_RETURN_ABSOLUTETIME(result);
}

/* abstime_timestamptz()
 * Convert abstime to timestamp with time zone.
 */
Datum
abstime_timestamptz(PG_FUNCTION_ARGS)
{
    AbsoluteTime abstime = PG_GETARG_ABSOLUTETIME(0);
    TimestampTz result;
    struct pg_tm tt,
               *tm = &tt;
    int         tz;
    char        zone[MAXDATELEN + 1],
               *tzn = zone;

    switch (abstime)
    {
        case INVALID_ABSTIME:
            ereport(ERROR,
                    (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                 errmsg("cannot convert abstime \"invalid\" to timestamp")));
            TIMESTAMP_NOBEGIN(result);
            break;

        case NOSTART_ABSTIME:
            TIMESTAMP_NOBEGIN(result);
            break;

        case NOEND_ABSTIME:
            TIMESTAMP_NOEND(result);
            break;

        default:
            abstime2tm(abstime, &tz, tm, &tzn);
            if (tm2timestamp(tm, 0, &tz, &result) != 0)
                ereport(ERROR,
                        (errcode(ERRCODE_DATETIME_VALUE_OUT_OF_RANGE),
                         errmsg("timestamp out of range")));
            break;
    };

    PG_RETURN_TIMESTAMP(result);
}


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

/*
 *      reltimein       - converts a reltime string in an internal format
 */
Datum
reltimein(PG_FUNCTION_ARGS)
{
    char       *str = PG_GETARG_CSTRING(0);
    RelativeTime result;
    struct pg_tm tt,
               *tm = &tt;
    fsec_t      fsec;
    int         dtype;
    int         dterr;
    char       *field[MAXDATEFIELDS];
    int         nf,
                ftype[MAXDATEFIELDS];
    char        workbuf[MAXDATELEN + 1];

    dterr = ParseDateTime(str, workbuf, sizeof(workbuf),
                          field, ftype, MAXDATEFIELDS, &nf);
    if (dterr == 0)
        dterr = DecodeInterval(field, ftype, nf, INTERVAL_FULL_RANGE,
                               &dtype, tm, &fsec);

    /* if those functions think it's a bad format, try ISO8601 style */
    if (dterr == DTERR_BAD_FORMAT)
        dterr = DecodeISO8601Interval(str,
                                      &dtype, tm, &fsec);

    if (dterr != 0)
    {
        if (dterr == DTERR_FIELD_OVERFLOW)
            dterr = DTERR_INTERVAL_OVERFLOW;
        DateTimeParseError(dterr, str, "reltime");
    }

    switch (dtype)
    {
        case DTK_DELTA:
            result = ((tm->tm_hour * MINS_PER_HOUR + tm->tm_min) * SECS_PER_MINUTE) + tm->tm_sec;
            result += tm->tm_year * SECS_PER_YEAR + ((tm->tm_mon * DAYS_PER_MONTH) + tm->tm_mday) * SECS_PER_DAY;
            break;

        default:
            elog(ERROR, "unexpected dtype %d while parsing reltime \"%s\"",
                 dtype, str);
            result = INVALID_RELTIME;
            break;
    }

    PG_RETURN_RELATIVETIME(result);
}

/*
 *      reltimeout      - converts the internal format to a reltime string
 */
Datum
reltimeout(PG_FUNCTION_ARGS)
{
    RelativeTime time = PG_GETARG_RELATIVETIME(0);
    char       *result;
    struct pg_tm tt,
               *tm = &tt;
    char        buf[MAXDATELEN + 1];

    reltime2tm(time, tm);
    EncodeInterval(tm, 0, IntervalStyle, buf);

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

/*
 *      reltimerecv         - converts external binary format to reltime
 */
Datum
reltimerecv(PG_FUNCTION_ARGS)
{
    StringInfo  buf = (StringInfo) PG_GETARG_POINTER(0);

    PG_RETURN_RELATIVETIME((RelativeTime) pq_getmsgint(buf, sizeof(RelativeTime)));
}

/*
 *      reltimesend         - converts reltime to binary format
 */
Datum
reltimesend(PG_FUNCTION_ARGS)
{
    RelativeTime time = PG_GETARG_RELATIVETIME(0);
    StringInfoData buf;

    pq_begintypsend(&buf);
    pq_sendint(&buf, time, sizeof(time));
    PG_RETURN_BYTEA_P(pq_endtypsend(&buf));
}


static void
reltime2tm(RelativeTime time, struct pg_tm * tm)
{
    double      dtime = time;

    FMODULO(dtime, tm->tm_year, 31557600);
    FMODULO(dtime, tm->tm_mon, 2592000);
    FMODULO(dtime, tm->tm_mday, SECS_PER_DAY);
    FMODULO(dtime, tm->tm_hour, SECS_PER_HOUR);
    FMODULO(dtime, tm->tm_min, SECS_PER_MINUTE);
    FMODULO(dtime, tm->tm_sec, 1);
}


/*
 *      tintervalin     - converts an tinterval string to internal format
 */
Datum
tintervalin(PG_FUNCTION_ARGS)
{
    char       *tintervalstr = PG_GETARG_CSTRING(0);
    TimeInterval tinterval;
    AbsoluteTime i_start,
                i_end,
                t1,
                t2;

    parsetinterval(tintervalstr, &t1, &t2);

    tinterval = (TimeInterval) palloc(sizeof(TimeIntervalData));

    if (t1 == INVALID_ABSTIME || t2 == INVALID_ABSTIME)
        tinterval->status = T_INTERVAL_INVAL;   /* undefined  */
    else
        tinterval->status = T_INTERVAL_VALID;

    i_start = ABSTIMEMIN(t1, t2);
    i_end = ABSTIMEMAX(t1, t2);
    tinterval->data[0] = i_start;
    tinterval->data[1] = i_end;

    PG_RETURN_TIMEINTERVAL(tinterval);
}


/*
 *      tintervalout    - converts an internal tinterval format to a string
 */
Datum
tintervalout(PG_FUNCTION_ARGS)
{
    TimeInterval tinterval = PG_GETARG_TIMEINTERVAL(0);
    char       *i_str,
               *p;

    i_str = (char *) palloc(T_INTERVAL_LEN);    /* ["..." "..."] */
    strcpy(i_str, "[\"");
    if (tinterval->status == T_INTERVAL_INVAL)
        strcat(i_str, INVALID_INTERVAL_STR);
    else
    {
        p = DatumGetCString(DirectFunctionCall1(abstimeout,
                                  AbsoluteTimeGetDatum(tinterval->data[0])));
        strcat(i_str, p);
        pfree(p);
        strcat(i_str, "\" \"");
        p = DatumGetCString(DirectFunctionCall1(abstimeout,
                                  AbsoluteTimeGetDatum(tinterval->data[1])));
        strcat(i_str, p);
        pfree(p);
    }
    strcat(i_str, "\"]");
    PG_RETURN_CSTRING(i_str);
}

/*
 *      tintervalrecv           - converts external binary format to tinterval
 */
Datum
tintervalrecv(PG_FUNCTION_ARGS)
{
    StringInfo  buf = (StringInfo) PG_GETARG_POINTER(0);
    TimeInterval tinterval;
    int32       status;

    tinterval = (TimeInterval) palloc(sizeof(TimeIntervalData));

    tinterval->status = pq_getmsgint(buf, sizeof(tinterval->status));
    tinterval->data[0] = pq_getmsgint(buf, sizeof(tinterval->data[0]));
    tinterval->data[1] = pq_getmsgint(buf, sizeof(tinterval->data[1]));

    if (tinterval->data[0] == INVALID_ABSTIME ||
        tinterval->data[1] == INVALID_ABSTIME)
        status = T_INTERVAL_INVAL;      /* undefined  */
    else
        status = T_INTERVAL_VALID;

    if (status != tinterval->status)
        ereport(ERROR,
                (errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
                 errmsg("invalid status in external \"tinterval\" value")));

    PG_RETURN_TIMEINTERVAL(tinterval);
}

/*
 *      tintervalsend           - converts tinterval to binary format
 */
Datum
tintervalsend(PG_FUNCTION_ARGS)
{
    TimeInterval tinterval = PG_GETARG_TIMEINTERVAL(0);
    StringInfoData buf;

    pq_begintypsend(&buf);
    pq_sendint(&buf, tinterval->status, sizeof(tinterval->status));
    pq_sendint(&buf, tinterval->data[0], sizeof(tinterval->data[0]));
    pq_sendint(&buf, tinterval->data[1], sizeof(tinterval->data[1]));
    PG_RETURN_BYTEA_P(pq_endtypsend(&buf));
}


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

Datum
interval_reltime(PG_FUNCTION_ARGS)
{
    Interval   *interval = PG_GETARG_INTERVAL_P(0);
    RelativeTime time;
    int         year,
                month,
                day;
    TimeOffset  span;

    year = interval->month / MONTHS_PER_YEAR;
    month = interval->month % MONTHS_PER_YEAR;
    day = interval->day;

#ifdef HAVE_INT64_TIMESTAMP
    span = ((INT64CONST(365250000) * year + INT64CONST(30000000) * month +
             INT64CONST(1000000) * day) * INT64CONST(86400)) +
        interval->time;
    span /= USECS_PER_SEC;
#else
    span = (DAYS_PER_YEAR * year + (double) DAYS_PER_MONTH * month + day) * SECS_PER_DAY + interval->time;
#endif

    if (span < INT_MIN || span > INT_MAX)
        time = INVALID_RELTIME;
    else
        time = span;

    PG_RETURN_RELATIVETIME(time);
}


Datum
reltime_interval(PG_FUNCTION_ARGS)
{
    RelativeTime reltime = PG_GETARG_RELATIVETIME(0);
    Interval   *result;
    int         year,
                month,
                day;

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

    switch (reltime)
    {
        case INVALID_RELTIME:
            ereport(ERROR,
                    (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
                  errmsg("cannot convert reltime \"invalid\" to interval")));
            result->time = 0;
            result->day = 0;
            result->month = 0;
            break;

        default:
#ifdef HAVE_INT64_TIMESTAMP
            year = reltime / SECS_PER_YEAR;
            reltime -= year * SECS_PER_YEAR;
            month = reltime / (DAYS_PER_MONTH * SECS_PER_DAY);
            reltime -= month * (DAYS_PER_MONTH * SECS_PER_DAY);
            day = reltime / SECS_PER_DAY;
            reltime -= day * SECS_PER_DAY;

            result->time = (reltime * USECS_PER_SEC);
#else
            TMODULO(reltime, year, SECS_PER_YEAR);
            TMODULO(reltime, month, DAYS_PER_MONTH * SECS_PER_DAY);
            TMODULO(reltime, day, SECS_PER_DAY);

            result->time = reltime;
#endif
            result->month = MONTHS_PER_YEAR * year + month;
            result->day = day;
            break;
    }

    PG_RETURN_INTERVAL_P(result);
}


/*
 *      mktinterval     - creates a time interval with endpoints t1 and t2
 */
Datum
mktinterval(PG_FUNCTION_ARGS)
{
    AbsoluteTime t1 = PG_GETARG_ABSOLUTETIME(0);
    AbsoluteTime t2 = PG_GETARG_ABSOLUTETIME(1);
    AbsoluteTime tstart = ABSTIMEMIN(t1, t2);
    AbsoluteTime tend = ABSTIMEMAX(t1, t2);
    TimeInterval tinterval;

    tinterval = (TimeInterval) palloc(sizeof(TimeIntervalData));

    if (t1 == INVALID_ABSTIME || t2 == INVALID_ABSTIME)
        tinterval->status = T_INTERVAL_INVAL;

    else
    {
        tinterval->status = T_INTERVAL_VALID;
        tinterval->data[0] = tstart;
        tinterval->data[1] = tend;
    }

    PG_RETURN_TIMEINTERVAL(tinterval);
}

/*
 *      timepl, timemi and abstimemi use the formula
 *              abstime + reltime = abstime
 *      so      abstime - reltime = abstime
 *      and     abstime - abstime = reltime
 */

/*
 *      timepl          - returns the value of (abstime t1 + reltime t2)
 */
Datum
timepl(PG_FUNCTION_ARGS)
{
    AbsoluteTime t1 = PG_GETARG_ABSOLUTETIME(0);
    RelativeTime t2 = PG_GETARG_RELATIVETIME(1);

    if (AbsoluteTimeIsReal(t1) &&
        RelativeTimeIsValid(t2) &&
        ((t2 > 0 && t1 < NOEND_ABSTIME - t2) ||
         (t2 <= 0 && t1 > NOSTART_ABSTIME - t2)))       /* prevent overflow */
        PG_RETURN_ABSOLUTETIME(t1 + t2);

    PG_RETURN_ABSOLUTETIME(INVALID_ABSTIME);
}


/*
 *      timemi          - returns the value of (abstime t1 - reltime t2)
 */
Datum
timemi(PG_FUNCTION_ARGS)
{
    AbsoluteTime t1 = PG_GETARG_ABSOLUTETIME(0);
    RelativeTime t2 = PG_GETARG_RELATIVETIME(1);

    if (AbsoluteTimeIsReal(t1) &&
        RelativeTimeIsValid(t2) &&
        ((t2 > 0 && t1 > NOSTART_ABSTIME + t2) ||
         (t2 <= 0 && t1 < NOEND_ABSTIME + t2))) /* prevent overflow */
        PG_RETURN_ABSOLUTETIME(t1 - t2);

    PG_RETURN_ABSOLUTETIME(INVALID_ABSTIME);
}


/*
 *      intinterval     - returns true iff absolute date is in the tinterval
 */
Datum
intinterval(PG_FUNCTION_ARGS)
{
    AbsoluteTime t = PG_GETARG_ABSOLUTETIME(0);
    TimeInterval tinterval = PG_GETARG_TIMEINTERVAL(1);

    if (tinterval->status == T_INTERVAL_VALID && t != INVALID_ABSTIME)
    {
        if (DatumGetBool(DirectFunctionCall2(abstimege,
                                             AbsoluteTimeGetDatum(t),
                                AbsoluteTimeGetDatum(tinterval->data[0]))) &&
            DatumGetBool(DirectFunctionCall2(abstimele,
                                             AbsoluteTimeGetDatum(t),
                                  AbsoluteTimeGetDatum(tinterval->data[1]))))
            PG_RETURN_BOOL(true);
    }
    PG_RETURN_BOOL(false);
}

/*
 *      tintervalrel        - returns  relative time corresponding to tinterval
 */
Datum
tintervalrel(PG_FUNCTION_ARGS)
{
    TimeInterval tinterval = PG_GETARG_TIMEINTERVAL(0);
    AbsoluteTime t1 = tinterval->data[0];
    AbsoluteTime t2 = tinterval->data[1];

    if (tinterval->status != T_INTERVAL_VALID)
        PG_RETURN_RELATIVETIME(INVALID_RELTIME);

    if (AbsoluteTimeIsReal(t1) &&
        AbsoluteTimeIsReal(t2))
        PG_RETURN_RELATIVETIME(t2 - t1);

    PG_RETURN_RELATIVETIME(INVALID_RELTIME);
}


/*
 *      timenow         - returns  time "now", internal format
 *
 *      Now AbsoluteTime is time since Jan 1 1970 -mer 7 Feb 1992
 */
Datum
timenow(PG_FUNCTION_ARGS)
{
    PG_RETURN_ABSOLUTETIME(GetCurrentAbsoluteTime());
}

/*
 * reltime comparison routines
 */
static int
reltime_cmp_internal(RelativeTime a, RelativeTime b)
{
    /*
     * We consider all INVALIDs to be equal and larger than any non-INVALID.
     * This is somewhat arbitrary; the important thing is to have a consistent
     * sort order.
     */
    if (a == INVALID_RELTIME)
    {
        if (b == INVALID_RELTIME)
            return 0;           /* INVALID = INVALID */
        else
            return 1;           /* INVALID > non-INVALID */
    }

    if (b == INVALID_RELTIME)
        return -1;              /* non-INVALID < INVALID */

    if (a > b)
        return 1;
    else if (a == b)
        return 0;
    else
        return -1;
}

Datum
reltimeeq(PG_FUNCTION_ARGS)
{
    RelativeTime t1 = PG_GETARG_RELATIVETIME(0);
    RelativeTime t2 = PG_GETARG_RELATIVETIME(1);

    PG_RETURN_BOOL(reltime_cmp_internal(t1, t2) == 0);
}

Datum
reltimene(PG_FUNCTION_ARGS)
{
    RelativeTime t1 = PG_GETARG_RELATIVETIME(0);
    RelativeTime t2 = PG_GETARG_RELATIVETIME(1);

    PG_RETURN_BOOL(reltime_cmp_internal(t1, t2) != 0);
}

Datum
reltimelt(PG_FUNCTION_ARGS)
{
    RelativeTime t1 = PG_GETARG_RELATIVETIME(0);
    RelativeTime t2 = PG_GETARG_RELATIVETIME(1);

    PG_RETURN_BOOL(reltime_cmp_internal(t1, t2) < 0);
}

Datum
reltimegt(PG_FUNCTION_ARGS)
{
    RelativeTime t1 = PG_GETARG_RELATIVETIME(0);
    RelativeTime t2 = PG_GETARG_RELATIVETIME(1);

    PG_RETURN_BOOL(reltime_cmp_internal(t1, t2) > 0);
}

Datum
reltimele(PG_FUNCTION_ARGS)
{
    RelativeTime t1 = PG_GETARG_RELATIVETIME(0);
    RelativeTime t2 = PG_GETARG_RELATIVETIME(1);

    PG_RETURN_BOOL(reltime_cmp_internal(t1, t2) <= 0);
}

Datum
reltimege(PG_FUNCTION_ARGS)
{
    RelativeTime t1 = PG_GETARG_RELATIVETIME(0);
    RelativeTime t2 = PG_GETARG_RELATIVETIME(1);

    PG_RETURN_BOOL(reltime_cmp_internal(t1, t2) >= 0);
}

Datum
btreltimecmp(PG_FUNCTION_ARGS)
{
    RelativeTime t1 = PG_GETARG_RELATIVETIME(0);
    RelativeTime t2 = PG_GETARG_RELATIVETIME(1);

    PG_RETURN_INT32(reltime_cmp_internal(t1, t2));
}


/*
 *      tintervalsame   - returns true iff tinterval i1 is same as tinterval i2
 *      Check begin and end time.
 */
Datum
tintervalsame(PG_FUNCTION_ARGS)
{
    TimeInterval i1 = PG_GETARG_TIMEINTERVAL(0);
    TimeInterval i2 = PG_GETARG_TIMEINTERVAL(1);

    if (i1->status == T_INTERVAL_INVAL || i2->status == T_INTERVAL_INVAL)
        PG_RETURN_BOOL(false);

    if (DatumGetBool(DirectFunctionCall2(abstimeeq,
                                         AbsoluteTimeGetDatum(i1->data[0]),
                                       AbsoluteTimeGetDatum(i2->data[0]))) &&
        DatumGetBool(DirectFunctionCall2(abstimeeq,
                                         AbsoluteTimeGetDatum(i1->data[1]),
                                         AbsoluteTimeGetDatum(i2->data[1]))))
        PG_RETURN_BOOL(true);
    PG_RETURN_BOOL(false);
}

/*
 * tinterval comparison routines
 *
 * Note: comparison is based only on the lengths of the tintervals, not on
 * endpoint values (as long as they're not INVALID).  This is pretty bogus,
 * but since it's only a legacy datatype, we're not going to change it.
 *
 * Some other bogus things that won't be changed for compatibility reasons:
 * 1. The interval length computations overflow at 2^31 seconds, causing
 * intervals longer than that to sort oddly compared to those shorter.
 * 2. infinity and minus infinity (NOEND_ABSTIME and NOSTART_ABSTIME) are
 * just ordinary integers.  Since this code doesn't handle them specially,
 * it's possible for [a b] to be considered longer than [c infinity] for
 * finite abstimes a, b, c.  In combination with the previous point, the
 * interval [-infinity infinity] is treated as being shorter than many finite
 * intervals :-(
 *
 * If tinterval is ever reimplemented atop timestamp, it'd be good to give
 * some consideration to avoiding these problems.
 */
static int
tinterval_cmp_internal(TimeInterval a, TimeInterval b)
{
    bool        a_invalid;
    bool        b_invalid;
    AbsoluteTime a_len;
    AbsoluteTime b_len;

    /*
     * We consider all INVALIDs to be equal and larger than any non-INVALID.
     * This is somewhat arbitrary; the important thing is to have a consistent
     * sort order.
     */
    a_invalid = a->status == T_INTERVAL_INVAL ||
        a->data[0] == INVALID_ABSTIME ||
        a->data[1] == INVALID_ABSTIME;
    b_invalid = b->status == T_INTERVAL_INVAL ||
        b->data[0] == INVALID_ABSTIME ||
        b->data[1] == INVALID_ABSTIME;

    if (a_invalid)
    {
        if (b_invalid)
            return 0;           /* INVALID = INVALID */
        else
            return 1;           /* INVALID > non-INVALID */
    }

    if (b_invalid)
        return -1;              /* non-INVALID < INVALID */

    a_len = a->data[1] - a->data[0];
    b_len = b->data[1] - b->data[0];

    if (a_len > b_len)
        return 1;
    else if (a_len == b_len)
        return 0;
    else
        return -1;
}

Datum
tintervaleq(PG_FUNCTION_ARGS)
{
    TimeInterval i1 = PG_GETARG_TIMEINTERVAL(0);
    TimeInterval i2 = PG_GETARG_TIMEINTERVAL(1);

    PG_RETURN_BOOL(tinterval_cmp_internal(i1, i2) == 0);
}

Datum
tintervalne(PG_FUNCTION_ARGS)
{
    TimeInterval i1 = PG_GETARG_TIMEINTERVAL(0);
    TimeInterval i2 = PG_GETARG_TIMEINTERVAL(1);

    PG_RETURN_BOOL(tinterval_cmp_internal(i1, i2) != 0);
}

Datum
tintervallt(PG_FUNCTION_ARGS)
{
    TimeInterval i1 = PG_GETARG_TIMEINTERVAL(0);
    TimeInterval i2 = PG_GETARG_TIMEINTERVAL(1);

    PG_RETURN_BOOL(tinterval_cmp_internal(i1, i2) < 0);
}

Datum
tintervalle(PG_FUNCTION_ARGS)
{
    TimeInterval i1 = PG_GETARG_TIMEINTERVAL(0);
    TimeInterval i2 = PG_GETARG_TIMEINTERVAL(1);

    PG_RETURN_BOOL(tinterval_cmp_internal(i1, i2) <= 0);
}

Datum
tintervalgt(PG_FUNCTION_ARGS)
{
    TimeInterval i1 = PG_GETARG_TIMEINTERVAL(0);
    TimeInterval i2 = PG_GETARG_TIMEINTERVAL(1);

    PG_RETURN_BOOL(tinterval_cmp_internal(i1, i2) > 0);
}

Datum
tintervalge(PG_FUNCTION_ARGS)
{
    TimeInterval i1 = PG_GETARG_TIMEINTERVAL(0);
    TimeInterval i2 = PG_GETARG_TIMEINTERVAL(1);

    PG_RETURN_BOOL(tinterval_cmp_internal(i1, i2) >= 0);
}

Datum
bttintervalcmp(PG_FUNCTION_ARGS)
{
    TimeInterval i1 = PG_GETARG_TIMEINTERVAL(0);
    TimeInterval i2 = PG_GETARG_TIMEINTERVAL(1);

    PG_RETURN_INT32(tinterval_cmp_internal(i1, i2));
}


/*
 *      tintervalleneq  - returns true iff length of tinterval i is equal to
 *                              reltime t
 *      tintervallenne  - returns true iff length of tinterval i is not equal
 *                              to reltime t
 *      tintervallenlt  - returns true iff length of tinterval i is less than
 *                              reltime t
 *      tintervallengt  - returns true iff length of tinterval i is greater
 *                              than reltime t
 *      tintervallenle  - returns true iff length of tinterval i is less or
 *                              equal than reltime t
 *      tintervallenge  - returns true iff length of tinterval i is greater or
 *                              equal than reltime t
 */
Datum
tintervalleneq(PG_FUNCTION_ARGS)
{
    TimeInterval i = PG_GETARG_TIMEINTERVAL(0);
    RelativeTime t = PG_GETARG_RELATIVETIME(1);
    RelativeTime rt;

    if (i->status == T_INTERVAL_INVAL || t == INVALID_RELTIME)
        PG_RETURN_BOOL(false);
    rt = DatumGetRelativeTime(DirectFunctionCall1(tintervalrel,
                                                  TimeIntervalGetDatum(i)));
    PG_RETURN_BOOL(rt != INVALID_RELTIME && rt == t);
}

Datum
tintervallenne(PG_FUNCTION_ARGS)
{
    TimeInterval i = PG_GETARG_TIMEINTERVAL(0);
    RelativeTime t = PG_GETARG_RELATIVETIME(1);
    RelativeTime rt;

    if (i->status == T_INTERVAL_INVAL || t == INVALID_RELTIME)
        PG_RETURN_BOOL(false);
    rt = DatumGetRelativeTime(DirectFunctionCall1(tintervalrel,
                                                  TimeIntervalGetDatum(i)));
    PG_RETURN_BOOL(rt != INVALID_RELTIME && rt != t);
}

Datum
tintervallenlt(PG_FUNCTION_ARGS)
{
    TimeInterval i = PG_GETARG_TIMEINTERVAL(0);
    RelativeTime t = PG_GETARG_RELATIVETIME(1);
    RelativeTime rt;

    if (i->status == T_INTERVAL_INVAL || t == INVALID_RELTIME)
        PG_RETURN_BOOL(false);
    rt = DatumGetRelativeTime(DirectFunctionCall1(tintervalrel,
                                                  TimeIntervalGetDatum(i)));
    PG_RETURN_BOOL(rt != INVALID_RELTIME && rt < t);
}

Datum
tintervallengt(PG_FUNCTION_ARGS)
{
    TimeInterval i = PG_GETARG_TIMEINTERVAL(0);
    RelativeTime t = PG_GETARG_RELATIVETIME(1);
    RelativeTime rt;

    if (i->status == T_INTERVAL_INVAL || t == INVALID_RELTIME)
        PG_RETURN_BOOL(false);
    rt = DatumGetRelativeTime(DirectFunctionCall1(tintervalrel,
                                                  TimeIntervalGetDatum(i)));
    PG_RETURN_BOOL(rt != INVALID_RELTIME && rt > t);
}

Datum
tintervallenle(PG_FUNCTION_ARGS)
{
    TimeInterval i = PG_GETARG_TIMEINTERVAL(0);
    RelativeTime t = PG_GETARG_RELATIVETIME(1);
    RelativeTime rt;

    if (i->status == T_INTERVAL_INVAL || t == INVALID_RELTIME)
        PG_RETURN_BOOL(false);
    rt = DatumGetRelativeTime(DirectFunctionCall1(tintervalrel,
                                                  TimeIntervalGetDatum(i)));
    PG_RETURN_BOOL(rt != INVALID_RELTIME && rt <= t);
}

Datum
tintervallenge(PG_FUNCTION_ARGS)
{
    TimeInterval i = PG_GETARG_TIMEINTERVAL(0);
    RelativeTime t = PG_GETARG_RELATIVETIME(1);
    RelativeTime rt;

    if (i->status == T_INTERVAL_INVAL || t == INVALID_RELTIME)
        PG_RETURN_BOOL(false);
    rt = DatumGetRelativeTime(DirectFunctionCall1(tintervalrel,
                                                  TimeIntervalGetDatum(i)));
    PG_RETURN_BOOL(rt != INVALID_RELTIME && rt >= t);
}

/*
 *      tintervalct     - returns true iff tinterval i1 contains tinterval i2
 */
Datum
tintervalct(PG_FUNCTION_ARGS)
{
    TimeInterval i1 = PG_GETARG_TIMEINTERVAL(0);
    TimeInterval i2 = PG_GETARG_TIMEINTERVAL(1);

    if (i1->status == T_INTERVAL_INVAL || i2->status == T_INTERVAL_INVAL)
        PG_RETURN_BOOL(false);
    if (DatumGetBool(DirectFunctionCall2(abstimele,
                                         AbsoluteTimeGetDatum(i1->data[0]),
                                       AbsoluteTimeGetDatum(i2->data[0]))) &&
        DatumGetBool(DirectFunctionCall2(abstimege,
                                         AbsoluteTimeGetDatum(i1->data[1]),
                                         AbsoluteTimeGetDatum(i2->data[1]))))
        PG_RETURN_BOOL(true);
    PG_RETURN_BOOL(false);
}

/*
 *      tintervalov     - returns true iff tinterval i1 (partially) overlaps i2
 */
Datum
tintervalov(PG_FUNCTION_ARGS)
{
    TimeInterval i1 = PG_GETARG_TIMEINTERVAL(0);
    TimeInterval i2 = PG_GETARG_TIMEINTERVAL(1);

    if (i1->status == T_INTERVAL_INVAL || i2->status == T_INTERVAL_INVAL)
        PG_RETURN_BOOL(false);
    if (DatumGetBool(DirectFunctionCall2(abstimelt,
                                         AbsoluteTimeGetDatum(i1->data[1]),
                                       AbsoluteTimeGetDatum(i2->data[0]))) ||
        DatumGetBool(DirectFunctionCall2(abstimegt,
                                         AbsoluteTimeGetDatum(i1->data[0]),
                                         AbsoluteTimeGetDatum(i2->data[1]))))
        PG_RETURN_BOOL(false);
    PG_RETURN_BOOL(true);
}

/*
 *      tintervalstart  - returns  the start of tinterval i
 */
Datum
tintervalstart(PG_FUNCTION_ARGS)
{
    TimeInterval i = PG_GETARG_TIMEINTERVAL(0);

    if (i->status == T_INTERVAL_INVAL)
        PG_RETURN_ABSOLUTETIME(INVALID_ABSTIME);
    PG_RETURN_ABSOLUTETIME(i->data[0]);
}

/*
 *      tintervalend        - returns  the end of tinterval i
 */
Datum
tintervalend(PG_FUNCTION_ARGS)
{
    TimeInterval i = PG_GETARG_TIMEINTERVAL(0);

    if (i->status == T_INTERVAL_INVAL)
        PG_RETURN_ABSOLUTETIME(INVALID_ABSTIME);
    PG_RETURN_ABSOLUTETIME(i->data[1]);
}


/*****************************************************************************
 *   PRIVATE ROUTINES                                                        *
 *****************************************************************************/

/*
 *      parsetinterval -- parse a tinterval string
 *
 *      output parameters:
 *              i_start, i_end: tinterval margins
 *
 *      Time interval:
 *      `[' {` '} `'' <AbsTime> `'' {` '} `'' <AbsTime> `'' {` '} `]'
 *
 *      OR  `Undefined Range'   (see also INVALID_INTERVAL_STR)
 *
 *      where <AbsTime> satisfies the syntax of absolute time.
 *
 *      e.g.  [  '  Jan 18 1902'   'Jan 1 00:00:00 1970']
 */
static void
parsetinterval(char *i_string,
               AbsoluteTime *i_start,
               AbsoluteTime *i_end)
{
    char       *p,
               *p1;
    char        c;

    p = i_string;
    /* skip leading blanks up to '[' */
    while ((c = *p) != '\0')
    {
        if (IsSpace(c))
            p++;
        else if (c != '[')
            goto bogus;         /* syntax error */
        else
            break;
    }
    if (c == '\0')
        goto bogus;             /* syntax error */
    p++;
    /* skip leading blanks up to '"' */
    while ((c = *p) != '\0')
    {
        if (IsSpace(c))
            p++;
        else if (c != '"')
            goto bogus;         /* syntax error */
        else
            break;
    }
    if (c == '\0')
        goto bogus;             /* syntax error */
    p++;
    if (strncmp(INVALID_INTERVAL_STR, p, strlen(INVALID_INTERVAL_STR)) == 0)
        goto bogus;             /* undefined range, handled like a syntax err. */
    /* search for the end of the first date and change it to a \0 */
    p1 = p;
    while ((c = *p1) != '\0')
    {
        if (c == '"')
            break;
        p1++;
    }
    if (c == '\0')
        goto bogus;             /* syntax error */
    *p1 = '\0';
    /* get the first date */
    *i_start = DatumGetAbsoluteTime(DirectFunctionCall1(abstimein,
                                                        CStringGetDatum(p)));
    /* undo change to \0 */
    *p1 = c;
    p = ++p1;
    /* skip blanks up to '"', beginning of second date */
    while ((c = *p) != '\0')
    {
        if (IsSpace(c))
            p++;
        else if (c != '"')
            goto bogus;         /* syntax error */
        else
            break;
    }
    if (c == '\0')
        goto bogus;             /* syntax error */
    p++;
    /* search for the end of the second date and change it to a \0 */
    p1 = p;
    while ((c = *p1) != '\0')
    {
        if (c == '"')
            break;
        p1++;
    }
    if (c == '\0')
        goto bogus;             /* syntax error */
    *p1 = '\0';
    /* get the second date */
    *i_end = DatumGetAbsoluteTime(DirectFunctionCall1(abstimein,
                                                      CStringGetDatum(p)));
    /* undo change to \0 */
    *p1 = c;
    p = ++p1;
    /* skip blanks up to ']' */
    while ((c = *p) != '\0')
    {
        if (IsSpace(c))
            p++;
        else if (c != ']')
            goto bogus;         /* syntax error */
        else
            break;
    }
    if (c == '\0')
        goto bogus;             /* syntax error */
    p++;
    c = *p;
    if (c != '\0')
        goto bogus;             /* syntax error */

    /* it seems to be a valid tinterval */
    return;

bogus:
    ereport(ERROR,
            (errcode(ERRCODE_INVALID_DATETIME_FORMAT),
             errmsg("invalid input syntax for type tinterval: \"%s\"",
                    i_string)));
    *i_start = *i_end = INVALID_ABSTIME;        /* keep compiler quiet */
}


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

/*
 * timeofday -
 *     returns the current time as a text. similar to timenow() but returns
 *     seconds with more precision (up to microsecs). (I need this to compare
 *     the Wisconsin benchmark with Illustra whose TimeNow() shows current
 *     time with precision up to microsecs.)              - ay 3/95
 */
Datum
timeofday(PG_FUNCTION_ARGS)
{
    struct timeval tp;
    char        templ[128];
    char        buf[128];
    pg_time_t   tt;

    gettimeofday(&tp, NULL);
    tt = (pg_time_t) tp.tv_sec;
    pg_strftime(templ, sizeof(templ), "%a %b %d %H:%M:%S.%%06d %Y %Z",
                pg_localtime(&tt, session_timezone));
    snprintf(buf, sizeof(buf), templ, tp.tv_usec);

    PG_RETURN_TEXT_P(cstring_to_text(buf));
}