timestamp.c

来自「postgresql8.3.4源码,开源数据库」· C语言 代码 · 共 1,001 行 · 第 1/2 页

#include "postgres_fe.h"

#include <time.h>
#include <float.h>
#include <limits.h>
#include <math.h>

#ifdef __FAST_MATH__
#error -ffast-math is known to break this code
#endif

#include "extern.h"
#include "dt.h"
#include "pgtypes_timestamp.h"
#include "pgtypes_date.h"


int PGTYPEStimestamp_defmt_scan(char **, char *, timestamp *, int *, int *, int *,
							int *, int *, int *, int *);

#ifdef HAVE_INT64_TIMESTAMP
static int64
time2t(const int hour, const int min, const int sec, const fsec_t fsec)
{
	return (((((hour * MINS_PER_HOUR) + min) * SECS_PER_MINUTE) + sec) * USECS_PER_SEC) + fsec;
}	/* time2t() */
#else
static double
time2t(const int hour, const int min, const int sec, const fsec_t fsec)
{
	return (((hour * MINS_PER_HOUR) + min) * SECS_PER_MINUTE) + sec + fsec;
}	/* time2t() */
#endif

static timestamp
dt2local(timestamp dt, int tz)
{
#ifdef HAVE_INT64_TIMESTAMP
	dt -= (tz * USECS_PER_SEC);
#else
	dt -= tz;
#endif
	return dt;
}	/* dt2local() */

/* 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.
 *
 * Returns -1 on failure (overflow).
 */
int
tm2timestamp(struct tm * tm, fsec_t fsec, int *tzp, timestamp * result)
{
#ifdef HAVE_INT64_TIMESTAMP
	int			dDate;
	int64		time;
#else
	double		dDate,
				time;
#endif

	/* 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;

	dDate = 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);
#ifdef HAVE_INT64_TIMESTAMP
	*result = (dDate * USECS_PER_DAY) + time;
	/* check for major overflow */
	if ((*result - time) / USECS_PER_DAY != dDate)
		return -1;
	/* check for just-barely overflow (okay except time-of-day wraps) */
	if ((*result < 0 && dDate >= 0) ||
		(*result >= 0 && dDate < 0))
		return -1;
#else
	*result = dDate * SECS_PER_DAY + time;
#endif
	if (tzp != NULL)
		*result = dt2local(*result, -(*tzp));

	return 0;
}	/* tm2timestamp() */

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

	GetEpochTime(tm);
	tm2timestamp(tm, 0, NULL, &dt);
	return dt;
}	/* SetEpochTimestamp() */

/* 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
 */
static int
timestamp2tm(timestamp dt, int *tzp, struct tm * tm, fsec_t *fsec, char **tzn)
{
#ifdef HAVE_INT64_TIMESTAMP
	int64		dDate,
				date0;
	int64		time;
#else
	double		dDate,
				date0;
	double		time;
#endif
	time_t		utime;

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

	date0 = date2j(2000, 1, 1);

#ifdef HAVE_INT64_TIMESTAMP
	time = dt;
	TMODULO(time, dDate, USECS_PER_DAY);

	if (time < INT64CONST(0))
	{
		time += USECS_PER_DAY;
		dDate -= 1;
	}

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

	/* Julian day routine does not work for negative Julian days */
	if (dDate < 0 || dDate > (timestamp) INT_MAX)
		return -1;

	j2date((int) dDate, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
	dt2time(time, &tm->tm_hour, &tm->tm_min, &tm->tm_sec, fsec);
#else
	time = dt;
	TMODULO(time, dDate, (double) SECS_PER_DAY);

	if (time < 0)
	{
		time += SECS_PER_DAY;
		dDate -= 1;
	}

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

recalc_d:
	/* Julian day routine does not work for negative Julian days */
	if (dDate < 0 || dDate > (timestamp) INT_MAX)
		return -1;

	j2date((int) dDate, &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
recalc_t:
	dt2time(time, &tm->tm_hour, &tm->tm_min, &tm->tm_sec, fsec);

	*fsec = TSROUND(*fsec);
	/* roundoff may need to propagate to higher-order fields */
	if (*fsec >= 1.0)
	{
		time = ceil(time);
		if (time >= (double) SECS_PER_DAY)
		{
			time = 0;
			dDate += 1;
			goto recalc_d;
		}
		goto recalc_t;
	}
#endif

	if (tzp != NULL)
	{
		/*
		 * Does this fall within the capabilities of the localtime()
		 * interface? Then use this to rotate to the local time zone.
		 */
		if (IS_VALID_UTIME(tm->tm_year, tm->tm_mon, tm->tm_mday))
		{
#ifdef HAVE_INT64_TIMESTAMP
			utime = dt / USECS_PER_SEC +
				((date0 - date2j(1970, 1, 1)) * INT64CONST(86400));
#else
			utime = dt + (date0 - date2j(1970, 1, 1)) * SECS_PER_DAY;
#endif

#if defined(HAVE_TM_ZONE) || defined(HAVE_INT_TIMEZONE)
			tx = localtime(&utime);
			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_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 - SECS_PER_HOUR : TIMEZONE_GLOBAL;
			if (tzn != NULL)
				*tzn = TZNAME_GLOBAL[(tm->tm_isdst > 0)];
#endif
#else							/* not (HAVE_TM_ZONE || HAVE_INT_TIMEZONE) */
			*tzp = 0;
			/* Mark this as *no* time zone available */
			tm->tm_isdst = -1;
			if (tzn != NULL)
				*tzn = NULL;
#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() */

/* 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() */

timestamp
PGTYPEStimestamp_from_asc(char *str, char **endptr)
{
	timestamp	result;

#ifdef HAVE_INT64_TIMESTAMP
	int64		noresult = 0;
#else
	double		noresult = 0.0;
#endif
	fsec_t		fsec;
	struct tm	tt,
			   *tm = &tt;
	int			dtype;
	int			nf;
	char	   *field[MAXDATEFIELDS];
	int			ftype[MAXDATEFIELDS];
	char		lowstr[MAXDATELEN + MAXDATEFIELDS];
	char	   *realptr;
	char	  **ptr = (endptr != NULL) ? endptr : &realptr;

	if (strlen(str) >= sizeof(lowstr))
	{
		errno = PGTYPES_TS_BAD_TIMESTAMP;
		return (noresult);
	}

	if (ParseDateTime(str, lowstr, field, ftype, MAXDATEFIELDS, &nf, ptr) != 0 ||
		DecodeDateTime(field, ftype, nf, &dtype, tm, &fsec, 0) != 0)
	{
		errno = PGTYPES_TS_BAD_TIMESTAMP;
		return (noresult);
	}

	switch (dtype)
	{
		case DTK_DATE:
			if (tm2timestamp(tm, fsec, NULL, &result) != 0)
			{
				errno = PGTYPES_TS_BAD_TIMESTAMP;
				return (noresult);
			}
			break;

		case DTK_EPOCH:
			result = SetEpochTimestamp();
			break;

		case DTK_LATE:
			TIMESTAMP_NOEND(result);
			break;

		case DTK_EARLY:
			TIMESTAMP_NOBEGIN(result);
			break;

		case DTK_INVALID:
			errno = PGTYPES_TS_BAD_TIMESTAMP;
			return (noresult);

		default:
			errno = PGTYPES_TS_BAD_TIMESTAMP;
			return (noresult);
	}

	/* AdjustTimestampForTypmod(&result, typmod); */

	/*
	 * Since it's difficult to test for noresult, make sure errno is 0 if no
	 * error occured.
	 */
	errno = 0;
	return result;
}

char *
PGTYPEStimestamp_to_asc(timestamp tstamp)
{
	struct tm	tt,
			   *tm = &tt;
	char		buf[MAXDATELEN + 1];
	char	   *tzn = NULL;
	fsec_t		fsec;
	int			DateStyle = 1;	/* this defaults to ISO_DATES, shall we make
								 * it an option? */

	if (TIMESTAMP_NOT_FINITE(tstamp))
		EncodeSpecialTimestamp(tstamp, buf);
	else if (timestamp2tm(tstamp, NULL, tm, &fsec, NULL) == 0)
		EncodeDateTime(tm, fsec, NULL, &tzn, DateStyle, buf, 0);
	else
	{
		errno = PGTYPES_TS_BAD_TIMESTAMP;
		return NULL;
	}
	return pgtypes_strdup(buf);
}

void
PGTYPEStimestamp_current(timestamp * ts)
{
	struct tm	tm;

	GetCurrentDateTime(&tm);
	tm2timestamp(&tm, 0, NULL, ts);
	return;
}

static int
dttofmtasc_replace(timestamp * ts, date dDate, int dow, struct tm * tm,
				   char *output, int *pstr_len, char *fmtstr)
{
	union un_fmt_comb replace_val;
	int			replace_type;
	int			i;
	char	   *p = fmtstr;
	char	   *q = output;

	while (*p)
	{
		if (*p == '%')
		{
			p++;
			/* fix compiler warning */
			replace_type = PGTYPES_TYPE_NOTHING;
			switch (*p)
			{
					/* the abbreviated name of the day in the week */
					/* XXX should be locale aware */
				case 'a':
					replace_val.str_val = pgtypes_date_weekdays_short[dow];
					replace_type = PGTYPES_TYPE_STRING_CONSTANT;
					break;
					/* the full name of the day in the week */
					/* XXX should be locale aware */
				case 'A':
					replace_val.str_val = days[dow];
					replace_type = PGTYPES_TYPE_STRING_CONSTANT;
					break;
					/* the abbreviated name of the month */
					/* XXX should be locale aware */
				case 'b':
				case 'h':
					replace_val.str_val = months[tm->tm_mon];
					replace_type = PGTYPES_TYPE_STRING_CONSTANT;
					break;
					/* the full name name of the month */
					/* XXX should be locale aware */
				case 'B':
					replace_val.str_val = pgtypes_date_months[tm->tm_mon];
					replace_type = PGTYPES_TYPE_STRING_CONSTANT;
					break;

					/*
					 * The	preferred  date  and  time	representation	for
					 * the current locale.
					 */
				case 'c':
					/* XXX */
					break;
					/* the century number with leading zeroes */
				case 'C':
					replace_val.uint_val = tm->tm_year / 100;
					replace_type = PGTYPES_TYPE_UINT_2_LZ;
					break;
					/* day with leading zeroes (01 - 31) */
				case 'd':
					replace_val.uint_val = tm->tm_mday;
					replace_type = PGTYPES_TYPE_UINT_2_LZ;
					break;
					/* the date in the format mm/dd/yy */
				case 'D':

					/*
					 * ts, dDate, dow, tm is information about the timestamp
					 *
					 * q is the start of the current output buffer
					 *
					 * pstr_len is a pointer to the remaining size of output,
					 * i.e. the size of q
					 */
					i = dttofmtasc_replace(ts, dDate, dow, tm,
										   q, pstr_len,
										   "%m/%d/%y");
					if (i)
						return i;
					break;
					/* day with leading spaces (01 - 31) */
				case 'e':
					replace_val.uint_val = tm->tm_mday;
					replace_type = PGTYPES_TYPE_UINT_2_LS;
					break;

					/*
					 * alternative format modifier
					 */
				case 'E':
					{
						char		tmp[4] = "%Ex";

						p++;
						if (*p == '\0')
							return -1;
						tmp[2] = *p;

						/*
						 * strftime's month is 0 based, ours is 1 based
						 */
						tm->tm_mon -= 1;
						i = strftime(q, *pstr_len, tmp, tm);
						if (i == 0)
							return -1;
						while (*q)
						{
							q++;
							(*pstr_len)--;
						}
						tm->tm_mon += 1;
						replace_type = PGTYPES_TYPE_NOTHING;
						break;
					}

					/*
					 * The ISO 8601 year with century as a decimal number. The
					 * 4-digit year corresponding to the ISO week number.
					 */
				case 'G':
					tm->tm_mon -= 1;
					i = strftime(q, *pstr_len, "%G", tm);
					if (i == 0)
						return -1;
					while (*q)
					{
						q++;