interval.c

postgresql8.3.4源码,开源数据库

/* $PostgreSQL: pgsql/src/interfaces/ecpg/pgtypeslib/interval.c,v 1.37 2007/08/22 08:20:58 meskes Exp $ */

#include "postgres_fe.h"
#include <time.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_error.h"
#include "pgtypes_interval.h"

/* DecodeInterval()
 * Interpret previously parsed fields for general time interval.
 * Return 0 if decoded and -1 if problems.
 *
 * Allow "date" field DTK_DATE since this could be just
 *	an unsigned floating point number. - thomas 1997-11-16
 *
 * Allow ISO-style time span, with implicit units on number of days
 *	preceding an hh:mm:ss field. - thomas 1998-04-30
 */
int
DecodeInterval(char **field, int *ftype, int nf, int *dtype, struct tm * tm, fsec_t *fsec)
{
	int			is_before = FALSE;

	char	   *cp;
	int			fmask = 0,
				tmask,
				type;
	int			i;
	int			val;
	double		fval;

	*dtype = DTK_DELTA;

	type = IGNORE_DTF;
	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;

	/* read through list backwards to pick up units before values */
	for (i = nf - 1; i >= 0; i--)
	{
		switch (ftype[i])
		{
			case DTK_TIME:
				if (DecodeTime(field[i], fmask, &tmask, tm, fsec) != 0)
					return -1;
				type = DTK_DAY;
				break;

			case DTK_TZ:

				/*
				 * Timezone is a token with a leading sign character and
				 * otherwise the same as a non-signed time field
				 */

				/*
				 * A single signed number ends up here, but will be rejected
				 * by DecodeTime(). So, work this out to drop through to
				 * DTK_NUMBER, which *can* tolerate this.
				 */
				cp = field[i] + 1;
				while (*cp != '\0' && *cp != ':' && *cp != '.')
					cp++;
				if (*cp == ':' && DecodeTime((field[i] + 1), fmask, &tmask, tm, fsec) == 0)
				{
					if (*field[i] == '-')
					{
						/* flip the sign on all fields */
						tm->tm_hour = -tm->tm_hour;
						tm->tm_min = -tm->tm_min;
						tm->tm_sec = -tm->tm_sec;
						*fsec = -(*fsec);
					}

					/*
					 * Set the next type to be a day, if units are not
					 * specified. This handles the case of '1 +02:03' since we
					 * are reading right to left.
					 */
					type = DTK_DAY;
					tmask = DTK_M(TZ);
					break;
				}
				else if (type == IGNORE_DTF)
				{
					if (*cp == '.')
					{
						/*
						 * Got a decimal point? Then assume some sort of
						 * seconds specification
						 */
						type = DTK_SECOND;
					}
					else if (*cp == '\0')
					{
						/*
						 * Only a signed integer? Then must assume a
						 * timezone-like usage
						 */
						type = DTK_HOUR;
					}
				}
				/* DROP THROUGH */

			case DTK_DATE:
			case DTK_NUMBER:
				val = strtol(field[i], &cp, 10);

				if (type == IGNORE_DTF)
					type = DTK_SECOND;

				if (*cp == '.')
				{
					fval = strtod(cp, &cp);
					if (*cp != '\0')
						return -1;

					if (val < 0)
						fval = -fval;
				}
				else if (*cp == '\0')
					fval = 0;
				else
					return -1;

				tmask = 0;		/* DTK_M(type); */

				switch (type)
				{
					case DTK_MICROSEC:
#ifdef HAVE_INT64_TIMESTAMP
						*fsec += val + fval;
#else
						*fsec += (val + fval) * 1e-6;
#endif
						break;

					case DTK_MILLISEC:
#ifdef HAVE_INT64_TIMESTAMP
						*fsec += (val + fval) * 1000;
#else
						*fsec += (val + fval) * 1e-3;
#endif
						break;

					case DTK_SECOND:
						tm->tm_sec += val;
#ifdef HAVE_INT64_TIMESTAMP
						*fsec += fval * 1000000;
#else
						*fsec += fval;
#endif
						tmask = DTK_M(SECOND);
						break;

					case DTK_MINUTE:
						tm->tm_min += val;
						if (fval != 0)
						{
							int			sec;

							fval *= SECS_PER_MINUTE;
							sec = fval;
							tm->tm_sec += sec;
#ifdef HAVE_INT64_TIMESTAMP
							*fsec += ((fval - sec) * 1000000);
#else
							*fsec += fval - sec;
#endif
						}
						tmask = DTK_M(MINUTE);
						break;

					case DTK_HOUR:
						tm->tm_hour += val;
						if (fval != 0)
						{
							int			sec;

							fval *= SECS_PER_HOUR;
							sec = fval;
							tm->tm_sec += sec;
#ifdef HAVE_INT64_TIMESTAMP
							*fsec += (fval - sec) * 1000000;
#else
							*fsec += fval - sec;
#endif
						}
						tmask = DTK_M(HOUR);
						break;

					case DTK_DAY:
						tm->tm_mday += val;
						if (fval != 0)
						{
							int			sec;

							fval *= SECS_PER_DAY;
							sec = fval;
							tm->tm_sec += sec;
#ifdef HAVE_INT64_TIMESTAMP
							*fsec += (fval - sec) * 1000000;
#else
							*fsec += fval - sec;
#endif
						}
						tmask = (fmask & DTK_M(DAY)) ? 0 : DTK_M(DAY);
						break;

					case DTK_WEEK:
						tm->tm_mday += val * 7;
						if (fval != 0)
						{
							int			extra_days;

							fval *= 7;
							extra_days = (int32) fval;
							tm->tm_mday += extra_days;
							fval -= extra_days;
							if (fval != 0)
							{
								int			sec;

								fval *= SECS_PER_DAY;
								sec = fval;
								tm->tm_sec += sec;
#ifdef HAVE_INT64_TIMESTAMP
								*fsec += (fval - sec) * 1000000;
#else
								*fsec += fval - sec;
#endif
							}
						}
						tmask = (fmask & DTK_M(DAY)) ? 0 : DTK_M(DAY);
						break;

					case DTK_MONTH:
						tm->tm_mon += val;
						if (fval != 0)
						{
							int			day;

							fval *= DAYS_PER_MONTH;
							day = fval;
							tm->tm_mday += day;
							fval -= day;
							if (fval != 0)
							{
								int			sec;

								fval *= SECS_PER_DAY;
								sec = fval;
								tm->tm_sec += sec;
#ifdef HAVE_INT64_TIMESTAMP
								*fsec += (fval - sec) * 1000000;
#else
								*fsec += fval - sec;
#endif
							}
						}
						tmask = DTK_M(MONTH);
						break;

					case DTK_YEAR:
						tm->tm_year += val;
						if (fval != 0)
							tm->tm_mon += fval * MONTHS_PER_YEAR;
						tmask = (fmask & DTK_M(YEAR)) ? 0 : DTK_M(YEAR);
						break;

					case DTK_DECADE:
						tm->tm_year += val * 10;
						if (fval != 0)
							tm->tm_mon += fval * MONTHS_PER_YEAR * 10;
						tmask = (fmask & DTK_M(YEAR)) ? 0 : DTK_M(YEAR);
						break;

					case DTK_CENTURY:
						tm->tm_year += val * 100;
						if (fval != 0)
							tm->tm_mon += fval * MONTHS_PER_YEAR * 100;
						tmask = (fmask & DTK_M(YEAR)) ? 0 : DTK_M(YEAR);
						break;

					case DTK_MILLENNIUM:
						tm->tm_year += val * 1000;
						if (fval != 0)
							tm->tm_mon += fval * MONTHS_PER_YEAR * 1000;
						tmask = (fmask & DTK_M(YEAR)) ? 0 : DTK_M(YEAR);
						break;

					default:
						return -1;
				}
				break;

			case DTK_STRING:
			case DTK_SPECIAL:
				type = DecodeUnits(i, field[i], &val);
				if (type == IGNORE_DTF)
					continue;

				tmask = 0;		/* DTK_M(type); */
				switch (type)
				{
					case UNITS:
						type = val;
						break;

					case AGO:
						is_before = TRUE;
						type = val;
						break;

					case RESERV:
						tmask = (DTK_DATE_M || DTK_TIME_M);
						*dtype = val;
						break;

					default:
						return -1;
				}
				break;

			default:
				return -1;
		}

		if (tmask & fmask)
			return -1;
		fmask |= tmask;
	}

	if (*fsec != 0)
	{
		int			sec;

#ifdef HAVE_INT64_TIMESTAMP
		sec = *fsec / USECS_PER_SEC;
		*fsec -= sec * USECS_PER_SEC;
#else
		TMODULO(*fsec, sec, 1.0);
#endif
		tm->tm_sec += sec;
	}

	if (is_before)
	{
		*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);
	}

	/* ensure that at least one time field has been found */
	return (fmask != 0) ? 0 : -1;
}	/* DecodeInterval() */

/* EncodeInterval()
 * Interpret time structure as a delta time and convert to string.
 *
 * Support "traditional Postgres" and ISO-8601 styles.
 * Actually, afaik ISO does not address time interval formatting,
 *	but this looks similar to the spec for absolute date/time.
 * - thomas 1998-04-30
 */
int
EncodeInterval(struct tm * tm, fsec_t fsec, int style, char *str)
{
	int			is_before = FALSE;
	int			is_nonzero = FALSE;
	char	   *cp = str;

	/*
	 * The sign of year and month are guaranteed to match, since they are
	 * stored internally as "month". But we'll need to check for is_before and