datetime.c

来自「postgresql8.3.4源码,开源数据库」· C语言 代码 · 共 717 行 · 第 1/2 页

/* $PostgreSQL: pgsql/src/interfaces/ecpg/pgtypeslib/datetime.c,v 1.34 2007/11/15 21:14:45 momjian Exp $ */

#include "postgres_fe.h"

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

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

date *
PGTYPESdate_new(void)
{
	date	   *result;

	result = (date *) pgtypes_alloc(sizeof(date));
	/* result can be NULL if we run out of memory */
	return result;
}

void
PGTYPESdate_free(date * d)
{
	free(d);
}

date
PGTYPESdate_from_timestamp(timestamp dt)
{
	date		dDate;

	dDate = 0;					/* suppress compiler warning */

	if (!TIMESTAMP_NOT_FINITE(dt))
	{
#ifdef HAVE_INT64_TIMESTAMP
		/* Microseconds to days */
		dDate = (dt / USECS_PER_DAY);
#else
		/* Seconds to days */
		dDate = (dt / (double) SECS_PER_DAY);
#endif
	}

	return dDate;
}

date
PGTYPESdate_from_asc(char *str, char **endptr)
{

	date		dDate;
	fsec_t		fsec;
	struct tm	tt,
			   *tm = &tt;
	int			dtype;
	int			nf;
	char	   *field[MAXDATEFIELDS];
	int			ftype[MAXDATEFIELDS];
	char		lowstr[MAXDATELEN + 1];
	char	   *realptr;
	char	  **ptr = (endptr != NULL) ? endptr : &realptr;

	bool		EuroDates = FALSE;

	errno = 0;
	if (strlen(str) >= sizeof(lowstr))
	{
		errno = PGTYPES_DATE_BAD_DATE;
		return INT_MIN;
	}

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

	switch (dtype)
	{
		case DTK_DATE:
			break;

		case DTK_EPOCH:
			GetEpochTime(tm);
			break;

		default:
			errno = PGTYPES_DATE_BAD_DATE;
			return INT_MIN;
	}

	dDate = (date2j(tm->tm_year, tm->tm_mon, tm->tm_mday) - date2j(2000, 1, 1));

	return dDate;
}

char *
PGTYPESdate_to_asc(date dDate)
{
	struct tm	tt,
			   *tm = &tt;
	char		buf[MAXDATELEN + 1];
	int			DateStyle = 1;
	bool		EuroDates = FALSE;

	j2date(dDate + date2j(2000, 1, 1), &(tm->tm_year), &(tm->tm_mon), &(tm->tm_mday));
	EncodeDateOnly(tm, DateStyle, buf, EuroDates);
	return pgtypes_strdup(buf);
}

void
PGTYPESdate_julmdy(date jd, int *mdy)
{
	int			y,
				m,
				d;

	j2date((int) (jd + date2j(2000, 1, 1)), &y, &m, &d);
	mdy[0] = m;
	mdy[1] = d;
	mdy[2] = y;
}

void
PGTYPESdate_mdyjul(int *mdy, date * jdate)
{
	/* month is mdy[0] */
	/* day	 is mdy[1] */
	/* year  is mdy[2] */

	*jdate = (date) (date2j(mdy[2], mdy[0], mdy[1]) - date2j(2000, 1, 1));
}

int
PGTYPESdate_dayofweek(date dDate)
{
	/*
	 * Sunday:	0 Monday:	   1 Tuesday:	  2 Wednesday:	 3 Thursday: 4
	 * Friday:		5 Saturday:    6
	 */
	return (int) (dDate + date2j(2000, 1, 1) + 1) % 7;
}

void
PGTYPESdate_today(date * d)
{
	struct tm	ts;

	GetCurrentDateTime(&ts);
	*d = date2j(ts.tm_year, ts.tm_mon, ts.tm_mday) - date2j(2000, 1, 1);
	return;
}

#define PGTYPES_DATE_NUM_MAX_DIGITS		20		/* should suffice for most
												 * years... */

#define PGTYPES_FMTDATE_DAY_DIGITS_LZ		1	/* LZ means "leading zeroes" */
#define PGTYPES_FMTDATE_DOW_LITERAL_SHORT	2
#define PGTYPES_FMTDATE_MONTH_DIGITS_LZ		3
#define PGTYPES_FMTDATE_MONTH_LITERAL_SHORT 4
#define PGTYPES_FMTDATE_YEAR_DIGITS_SHORT	5
#define PGTYPES_FMTDATE_YEAR_DIGITS_LONG	6

int
PGTYPESdate_fmt_asc(date dDate, char *fmtstring, char *outbuf)
{
	static struct
	{
		char	   *format;
		int			component;
	}			mapping[] =
	{
		/*
		 * format items have to be sorted according to their length, since the
		 * first pattern that matches gets replaced by its value
		 */
		{
			"ddd", PGTYPES_FMTDATE_DOW_LITERAL_SHORT
		},
		{
			"dd", PGTYPES_FMTDATE_DAY_DIGITS_LZ
		},
		{
			"mmm", PGTYPES_FMTDATE_MONTH_LITERAL_SHORT
		},
		{
			"mm", PGTYPES_FMTDATE_MONTH_DIGITS_LZ
		},
		{
			"yyyy", PGTYPES_FMTDATE_YEAR_DIGITS_LONG
		},
		{
			"yy", PGTYPES_FMTDATE_YEAR_DIGITS_SHORT
		},
		{
			NULL, 0
		}
	};

	union un_fmt_comb replace_val;
	int			replace_type;

	int			i;
	int			dow;
	char	   *start_pattern;
	struct tm	tm;

	/* copy the string over */
	strcpy(outbuf, fmtstring);

	/* get the date */
	j2date(dDate + date2j(2000, 1, 1), &(tm.tm_year), &(tm.tm_mon), &(tm.tm_mday));
	dow = PGTYPESdate_dayofweek(dDate);

	for (i = 0; mapping[i].format != NULL; i++)
	{
		while ((start_pattern = strstr(outbuf, mapping[i].format)) != NULL)
		{
			switch (mapping[i].component)
			{
				case PGTYPES_FMTDATE_DOW_LITERAL_SHORT:
					replace_val.str_val = pgtypes_date_weekdays_short[dow];
					replace_type = PGTYPES_TYPE_STRING_CONSTANT;
					break;
				case PGTYPES_FMTDATE_DAY_DIGITS_LZ:
					replace_val.uint_val = tm.tm_mday;
					replace_type = PGTYPES_TYPE_UINT_2_LZ;
					break;
				case PGTYPES_FMTDATE_MONTH_LITERAL_SHORT:
					replace_val.str_val = months[tm.tm_mon - 1];
					replace_type = PGTYPES_TYPE_STRING_CONSTANT;
					break;
				case PGTYPES_FMTDATE_MONTH_DIGITS_LZ:
					replace_val.uint_val = tm.tm_mon;
					replace_type = PGTYPES_TYPE_UINT_2_LZ;
					break;
				case PGTYPES_FMTDATE_YEAR_DIGITS_LONG:
					replace_val.uint_val = tm.tm_year;
					replace_type = PGTYPES_TYPE_UINT_4_LZ;
					break;
				case PGTYPES_FMTDATE_YEAR_DIGITS_SHORT:
					replace_val.uint_val = tm.tm_year % 100;
					replace_type = PGTYPES_TYPE_UINT_2_LZ;
					break;
				default:

					/*
					 * should not happen, set something anyway
					 */
					replace_val.str_val = " ";
					replace_type = PGTYPES_TYPE_STRING_CONSTANT;
			}
			switch (replace_type)
			{
				case PGTYPES_TYPE_STRING_MALLOCED:
				case PGTYPES_TYPE_STRING_CONSTANT:
					strncpy(start_pattern, replace_val.str_val,
							strlen(replace_val.str_val));
					if (replace_type == PGTYPES_TYPE_STRING_MALLOCED)
						free(replace_val.str_val);
					break;
				case PGTYPES_TYPE_UINT:
					{
						char	   *t = pgtypes_alloc(PGTYPES_DATE_NUM_MAX_DIGITS);

						if (!t)
							return -1;
						snprintf(t, PGTYPES_DATE_NUM_MAX_DIGITS,
								 "%u", replace_val.uint_val);
						strncpy(start_pattern, t, strlen(t));
						free(t);
					}
					break;
				case PGTYPES_TYPE_UINT_2_LZ:
					{
						char	   *t = pgtypes_alloc(PGTYPES_DATE_NUM_MAX_DIGITS);

						if (!t)
							return -1;
						snprintf(t, PGTYPES_DATE_NUM_MAX_DIGITS,
								 "%02u", replace_val.uint_val);
						strncpy(start_pattern, t, strlen(t));
						free(t);
					}
					break;
				case PGTYPES_TYPE_UINT_4_LZ:
					{
						char	   *t = pgtypes_alloc(PGTYPES_DATE_NUM_MAX_DIGITS);

						if (!t)
							return -1;
						snprintf(t, PGTYPES_DATE_NUM_MAX_DIGITS,
								 "%04u", replace_val.uint_val);
						strncpy(start_pattern, t, strlen(t));
						free(t);
					}
					break;
				default:

					/*
					 * doesn't happen (we set replace_type to
					 * PGTYPES_TYPE_STRING_CONSTANT in case of an error above)
					 */
					break;
			}
		}
	}
	return 0;
}


/*
 * PGTYPESdate_defmt_asc
 *
 * function works as follows:
 *	 - first we analyze the paramters
 *	 - if this is a special case with no delimiters, add delimters
 *	 - find the tokens. First we look for numerical values. If we have found
 *	   less than 3 tokens, we check for the months' names and thereafter for
 *	   the abbreviations of the months' names.
 *	 - then we see which parameter should be the date, the month and the
 *	   year and from these values we calculate the date
 */

#define PGTYPES_DATE_MONTH_MAXLENGTH		20	/* probably even less  :-) */
int
PGTYPESdate_defmt_asc(date * d, char *fmt, char *str)
{
	/*
	 * token[2] = { 4,6 } means that token 2 starts at position 4 and ends at
	 * (including) position 6
	 */
	int			token[3][2];
	int			token_values[3] = {-1, -1, -1};
	char	   *fmt_token_order;
	char	   *fmt_ystart,
			   *fmt_mstart,
			   *fmt_dstart;
	int			i;
	int			reading_digit;
	int			token_count;
	char	   *str_copy;
	struct tm	tm;

	tm.tm_year = tm.tm_mon = tm.tm_mday = 0;	/* keep compiler quiet */

	if (!d || !str || !fmt)
	{
		errno = PGTYPES_DATE_ERR_EARGS;
		return -1;
	}

	/* analyze the fmt string */