datetime.c

来自「postgresql8.3.4源码,开源数据库」· C语言 代码 · 共 2,681 行 · 第 1/5 页

 * Return 0 if okay, a DTERR code if not.
 */
static int
ValidateDate(int fmask, bool is2digits, bool bc, struct pg_tm * tm)
{
	if (fmask & DTK_M(YEAR))
	{
		/* there is no year zero in AD/BC notation; i.e. "1 BC" == year 0 */
		if (bc)
		{
			if (tm->tm_year > 0)
				tm->tm_year = -(tm->tm_year - 1);
			else
				ereport(ERROR,
						(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
						 errmsg("inconsistent use of year %04d and \"BC\"",
								tm->tm_year)));
		}
		else if (is2digits)
		{
			if (tm->tm_year < 70)
				tm->tm_year += 2000;
			else if (tm->tm_year < 100)
				tm->tm_year += 1900;
		}
	}

	/* now that we have correct year, decode DOY */
	if (fmask & DTK_M(DOY))
	{
		j2date(date2j(tm->tm_year, 1, 1) + tm->tm_yday - 1,
			   &tm->tm_year, &tm->tm_mon, &tm->tm_mday);
	}

	/* check for valid month */
	if (fmask & DTK_M(MONTH))
	{
		if (tm->tm_mon < 1 || tm->tm_mon > MONTHS_PER_YEAR)
			return DTERR_MD_FIELD_OVERFLOW;
	}

	/* minimal check for valid day */
	if (fmask & DTK_M(DAY))
	{
		if (tm->tm_mday < 1 || tm->tm_mday > 31)
			return DTERR_MD_FIELD_OVERFLOW;
	}

	if ((fmask & DTK_DATE_M) == DTK_DATE_M)
	{
		/*
		 * Check for valid day of month, now that we know for sure the month
		 * and year.  Note we don't use MD_FIELD_OVERFLOW here, since it seems
		 * unlikely that "Feb 29" is a YMD-order error.
		 */
		if (tm->tm_mday > day_tab[isleap(tm->tm_year)][tm->tm_mon - 1])
			return DTERR_FIELD_OVERFLOW;
	}

	return 0;
}


/* DecodeTime()
 * Decode time string which includes delimiters.
 * Return 0 if okay, a DTERR code if not.
 *
 * Only check the lower limit on hours, since this same code can be
 * used to represent time spans.
 */
static int
DecodeTime(char *str, int fmask, int *tmask, struct pg_tm * tm, fsec_t *fsec)
{
	char	   *cp;

	*tmask = DTK_TIME_M;

	errno = 0;
	tm->tm_hour = strtoi(str, &cp, 10);
	if (errno == ERANGE)
		return DTERR_FIELD_OVERFLOW;
	if (*cp != ':')
		return DTERR_BAD_FORMAT;
	str = cp + 1;
	errno = 0;
	tm->tm_min = strtoi(str, &cp, 10);
	if (errno == ERANGE)
		return DTERR_FIELD_OVERFLOW;
	if (*cp == '\0')
	{
		tm->tm_sec = 0;
		*fsec = 0;
	}
	else if (*cp != ':')
		return DTERR_BAD_FORMAT;
	else
	{
		str = cp + 1;
		errno = 0;
		tm->tm_sec = strtoi(str, &cp, 10);
		if (errno == ERANGE)
			return DTERR_FIELD_OVERFLOW;
		if (*cp == '\0')
			*fsec = 0;
		else if (*cp == '.')
		{
			double		frac;

			str = cp;
			frac = strtod(str, &cp);
			if (*cp != '\0')
				return DTERR_BAD_FORMAT;
#ifdef HAVE_INT64_TIMESTAMP
			*fsec = rint(frac * 1000000);
#else
			*fsec = frac;
#endif
		}
		else
			return DTERR_BAD_FORMAT;
	}

	/* do a sanity check */
#ifdef HAVE_INT64_TIMESTAMP
	if (tm->tm_hour < 0 || tm->tm_min < 0 || tm->tm_min > 59 ||
		tm->tm_sec < 0 || tm->tm_sec > 60 || *fsec < INT64CONST(0) ||
		*fsec >= USECS_PER_SEC)
		return DTERR_FIELD_OVERFLOW;
#else
	if (tm->tm_hour < 0 || tm->tm_min < 0 || tm->tm_min > 59 ||
		tm->tm_sec < 0 || tm->tm_sec > 60 || *fsec < 0 || *fsec >= 1)
		return DTERR_FIELD_OVERFLOW;
#endif

	return 0;
}


/* DecodeNumber()
 * Interpret plain numeric field as a date value in context.
 * Return 0 if okay, a DTERR code if not.
 */
static int
DecodeNumber(int flen, char *str, bool haveTextMonth, int fmask,
			 int *tmask, struct pg_tm * tm, fsec_t *fsec, bool *is2digits)
{
	int			val;
	char	   *cp;
	int			dterr;

	*tmask = 0;

	errno = 0;
	val = strtoi(str, &cp, 10);
	if (errno == ERANGE)
		return DTERR_FIELD_OVERFLOW;
	if (cp == str)
		return DTERR_BAD_FORMAT;

	if (*cp == '.')
	{
		double		frac;

		/*
		 * More than two digits before decimal point? Then could be a date or
		 * a run-together time: 2001.360 20011225 040506.789
		 */
		if (cp - str > 2)
		{
			dterr = DecodeNumberField(flen, str,
									  (fmask | DTK_DATE_M),
									  tmask, tm,
									  fsec, is2digits);
			if (dterr < 0)
				return dterr;
			return 0;
		}

		frac = strtod(cp, &cp);
		if (*cp != '\0')
			return DTERR_BAD_FORMAT;
#ifdef HAVE_INT64_TIMESTAMP
		*fsec = rint(frac * 1000000);
#else
		*fsec = frac;
#endif
	}
	else if (*cp != '\0')
		return DTERR_BAD_FORMAT;

	/* Special case for day of year */
	if (flen == 3 && (fmask & DTK_DATE_M) == DTK_M(YEAR) && val >= 1 &&
		val <= 366)
	{
		*tmask = (DTK_M(DOY) | DTK_M(MONTH) | DTK_M(DAY));
		tm->tm_yday = val;
		/* tm_mon and tm_mday can't actually be set yet ... */
		return 0;
	}

	/* Switch based on what we have so far */
	switch (fmask & DTK_DATE_M)
	{
		case 0:

			/*
			 * Nothing so far; make a decision about what we think the input
			 * is.	There used to be lots of heuristics here, but the
			 * consensus now is to be paranoid.  It *must* be either
			 * YYYY-MM-DD (with a more-than-two-digit year field), or the
			 * field order defined by DateOrder.
			 */
			if (flen >= 3 || DateOrder == DATEORDER_YMD)
			{
				*tmask = DTK_M(YEAR);
				tm->tm_year = val;
			}
			else if (DateOrder == DATEORDER_DMY)
			{
				*tmask = DTK_M(DAY);
				tm->tm_mday = val;
			}
			else
			{
				*tmask = DTK_M(MONTH);
				tm->tm_mon = val;
			}
			break;

		case (DTK_M(YEAR)):
			/* Must be at second field of YY-MM-DD */
			*tmask = DTK_M(MONTH);
			tm->tm_mon = val;
			break;

		case (DTK_M(MONTH)):
			if (haveTextMonth)
			{
				/*
				 * We are at the first numeric field of a date that included a
				 * textual month name.	We want to support the variants
				 * MON-DD-YYYY, DD-MON-YYYY, and YYYY-MON-DD as unambiguous
				 * inputs.	We will also accept MON-DD-YY or DD-MON-YY in
				 * either DMY or MDY modes, as well as YY-MON-DD in YMD mode.
				 */
				if (flen >= 3 || DateOrder == DATEORDER_YMD)
				{
					*tmask = DTK_M(YEAR);
					tm->tm_year = val;
				}
				else
				{
					*tmask = DTK_M(DAY);
					tm->tm_mday = val;
				}
			}
			else
			{
				/* Must be at second field of MM-DD-YY */
				*tmask = DTK_M(DAY);
				tm->tm_mday = val;
			}
			break;

		case (DTK_M(YEAR) | DTK_M(MONTH)):
			if (haveTextMonth)
			{
				/* Need to accept DD-MON-YYYY even in YMD mode */
				if (flen >= 3 && *is2digits)
				{
					/* Guess that first numeric field is day was wrong */
					*tmask = DTK_M(DAY);		/* YEAR is already set */
					tm->tm_mday = tm->tm_year;
					tm->tm_year = val;
					*is2digits = FALSE;
				}
				else
				{
					*tmask = DTK_M(DAY);
					tm->tm_mday = val;
				}
			}
			else
			{
				/* Must be at third field of YY-MM-DD */
				*tmask = DTK_M(DAY);
				tm->tm_mday = val;
			}
			break;

		case (DTK_M(DAY)):
			/* Must be at second field of DD-MM-YY */
			*tmask = DTK_M(MONTH);
			tm->tm_mon = val;
			break;

		case (DTK_M(MONTH) | DTK_M(DAY)):
			/* Must be at third field of DD-MM-YY or MM-DD-YY */
			*tmask = DTK_M(YEAR);
			tm->tm_year = val;
			break;

		case (DTK_M(YEAR) | DTK_M(MONTH) | DTK_M(DAY)):
			/* we have all the date, so it must be a time field */
			dterr = DecodeNumberField(flen, str, fmask,
									  tmask, tm,
									  fsec, is2digits);
			if (dterr < 0)
				return dterr;
			return 0;

		default:
			/* Anything else is bogus input */
			return DTERR_BAD_FORMAT;
	}

	/*
	 * When processing a year field, mark it for adjustment if it's only one
	 * or two digits.
	 */
	if (*tmask == DTK_M(YEAR))
		*is2digits = (flen <= 2);

	return 0;
}


/* DecodeNumberField()
 * Interpret numeric string as a concatenated date or time field.
 * Return a DTK token (>= 0) if successful, a DTERR code (< 0) if not.
 *
 * Use the context of previously decoded fields to help with
 * the interpretation.
 */
static int
DecodeNumberField(int len, char *str, int fmask,
				int *tmask, struct pg_tm * tm, fsec_t *fsec, bool *is2digits)
{
	char	   *cp;

	/*
	 * Have a decimal point? Then this is a date or something with a seconds
	 * field...
	 */
	if ((cp = strchr(str, '.')) != NULL)
	{
		double		frac;

		frac = strtod(cp, NULL);
#ifdef HAVE_INT64_TIMESTAMP
		*fsec = rint(frac * 1000000);
#else
		*fsec = frac;
#endif
		*cp = '\0';
		len = strlen(str);
	}
	/* No decimal point and no complete date yet? */
	else if ((fmask & DTK_DATE_M) != DTK_DATE_M)
	{
		/* yyyymmdd? */
		if (len == 8)
		{
			*tmask = DTK_DATE_M;

			tm->tm_mday = atoi(str + 6);
			*(str + 6) = '\0';
			tm->tm_mon = atoi(str + 4);
			*(str + 4) = '\0';
			tm->tm_year = atoi(str + 0);

			return DTK_DATE;
		}
		/* yymmdd? */
		else if (len == 6)
		{
			*tmask = DTK_DATE_M;
			tm->tm_mday = atoi(str + 4);
			*(str + 4) = '\0';
			tm->tm_mon = atoi(str + 2);
			*(str + 2) = '\0';
			tm->tm_year = atoi(str + 0);
			*is2digits = TRUE;

			return DTK_DATE;
		}
	}

	/* not all time fields are specified? */
	if ((fmask & DTK_TIME_M) != DTK_TIME_M)
	{
		/* hhmmss */
		if (len == 6)
		{
			*tmask = DTK_TIME_M;
			tm->tm_sec = atoi(str + 4);
			*(str + 4) = '\0';
			tm->tm_min = atoi(str + 2);
			*(str + 2) = '\0';
			tm->tm_hour = atoi(str + 0);

			return DTK_TIME;
		}
		/* hhmm? */
		else if (len == 4)
		{
			*tmask = DTK_TIME_M;
			tm->tm_sec = 0;
			tm->tm_min = atoi(str + 2);
			*(str + 2) = '\0';
			tm->tm_hour = atoi(str + 0);

			return DTK_TIME;
		}
	}

	return DTERR_BAD_FORMAT;
}


/* DecodeTimezone()
 * Interpret string as a numeric timezone.
 *
 * Return 0 if okay (and set *tzp), a DTERR code if not okay.
 *
 * NB: this must *not* ereport on failure; see commands/variable.c.
 *
 * Note: we allow timezone offsets up to 13:59.  There are places that
 * use +1300 summer time.
 */
static int
DecodeTimezone(char *str, int *tzp)
{
	int			tz;
	int			hr,
				min,
				sec = 0;
	char	   *cp;

	/* leading character must be "+" or "-" */
	if (*str != '+' && *str != '-')
		return DTERR_BAD_FORMAT;

	errno = 0;
	hr = strtoi(str + 1, &cp, 10);
	if (errno == ERANGE)
		return DTERR_TZDISP_OVERFLOW;

	/* explicit delimiter? */
	if (*cp == ':')
	{
		errno = 0;
		min = strtoi(cp + 1, &cp, 10);
		if (errno == ERANGE)
			return DTERR_TZDISP_OVERFLOW;
		if (*cp == ':')
		{
			errno = 0;
			sec = strtoi(cp + 1, &cp, 10);
			if (errno == ERANGE)
				return DTERR_TZDISP_OVERFLOW;
		}
	}
	/* otherwise, might have run things together... */
	else if (*cp == '\0' && strlen(str) > 3)
	{
		min = hr % 100;
		hr = hr / 100;
		/* we could, but don't, support a run-together hhmmss format */
	}
	else
		min = 0;

	if (hr < 0 || hr > 14)
		return DTERR_TZDISP_OVERFLOW;
	if (min < 0 || min >= 60)
		return DTERR_TZDISP_OVERFLOW;
	if (sec < 0 || sec >= 60)
		return DTERR_TZDISP_OVERFLOW;

	tz = (hr * MINS_PER_HOUR + min) * SECS_PER_MINUTE + sec;
	if (*str == '-')
		tz = -tz;

	*tzp = -tz;

	if (*cp != '\0')
		return DTERR_BAD_FORMAT;

	return 0;
}

/* DecodeSpecial()
 * Decode text string using lookup table.
 *
 * Implement a cache lookup since it is likely that dates
 *	will be related in format.
 *
 * NB: this must *not* ereport on failure;
 * see commands/variable.c.
 */
int
DecodeSpecial(int field, char *lowtoken, int *val)
{
	int			type;
	const datetkn *tp;

	tp = datecache[field];
	if (tp == NULL || strncmp(lowtoken, tp->token, TOKMAXLEN) != 0)
	{
		tp = datebsearch(lowtoken, timezonetktbl, sztimezonetktbl);
		if (tp == NULL)
			tp = datebsearch(lowtoken, datetktbl, szdatetktbl);
	}
	if (tp == NULL)
	{
		type = UNKNOWN_FIELD;
		*val = 0;
	}
	else
	{
		datecache[field] = tp;
		type = tp->type;
		switch (type)
		{
			case TZ:
			case DTZ:
			case DTZMOD:
				*val = FROMVAL(tp);
				break;

			default:
				*val