tcldate.c

tcl是工具命令语言

     * represented by the date, then multiply by the number of seconds/day.
     */
    for (Julian = Day - 1, i = 0; i < Month; i++)
        Julian += DaysInMonth[i];
    if (Year >= EPOCH) {
        for (i = EPOCH; i < Year; i++)
            Julian += 365 + IsLeapYear(i);
    } else {
        for (i = Year; i < EPOCH; i++)
            Julian -= 365 + IsLeapYear(i);
    }
    Julian *= SECSPERDAY;

    /* Add the timezone offset ?? */
    Julian += TclDateTimezone * 60L;

    /* Add the number of seconds represented by the time component */
    if ((tod = ToSeconds(Hours, Minutes, Seconds, Meridian)) < 0)
        return -1;
    Julian += tod;

    /* Perform a preliminary DST compensation ?? */
    if (DSTmode == DSTon
     || (DSTmode == DSTmaybe && TclpGetDate((TclpTime_t)&Julian, 0)->tm_isdst))
        Julian -= 60 * 60;
    *TimePtr = Julian;
    return 0;
}


static time_t
DSTcorrect(Start, Future)
    time_t      Start;
    time_t      Future;
{
    time_t      StartDay;
    time_t      FutureDay;
    StartDay = (TclpGetDate((TclpTime_t)&Start, 0)->tm_hour + 1) % 24;
    FutureDay = (TclpGetDate((TclpTime_t)&Future, 0)->tm_hour + 1) % 24;
    return (Future - Start) + (StartDay - FutureDay) * 60L * 60L;
}


static time_t
NamedDay(Start, DayOrdinal, DayNumber)
    time_t      Start;
    time_t      DayOrdinal;
    time_t      DayNumber;
{
    struct tm   *tm;
    time_t      now;

    now = Start;
    tm = TclpGetDate((TclpTime_t)&now, 0);
    now += SECSPERDAY * ((DayNumber - tm->tm_wday + 7) % 7);
    now += 7 * SECSPERDAY * (DayOrdinal <= 0 ? DayOrdinal : DayOrdinal - 1);
    return DSTcorrect(Start, now);
}

static time_t
NamedMonth(Start, MonthOrdinal, MonthNumber)
    time_t Start;
    time_t MonthOrdinal;
    time_t MonthNumber;
{
    struct tm *tm;
    time_t now;
    int result;
    
    now = Start;
    tm = TclpGetDate((TclpTime_t)&now, 0);
    /* To compute the next n'th month, we use this alg:
     * add n to year value
     * if currentMonth < requestedMonth decrement year value by 1 (so that
     *  doing next february from january gives us february of the current year)
     * set day to 1, time to 0
     */
    tm->tm_year += MonthOrdinal;
    if (tm->tm_mon < MonthNumber - 1) {
	tm->tm_year--;
    }
    result = Convert(MonthNumber, (time_t) 1, tm->tm_year + TM_YEAR_BASE,
	    (time_t) 0, (time_t) 0, (time_t) 0, MER24, DSTmaybe, &now);
    if (result < 0) {
	return 0;
    }
    return DSTcorrect(Start, now);
}

static int
RelativeMonth(Start, RelMonth, TimePtr)
    time_t Start;
    time_t RelMonth;
    time_t *TimePtr;
{
    struct tm *tm;
    time_t Month;
    time_t Year;
    time_t Julian;
    int result;

    if (RelMonth == 0) {
        *TimePtr = 0;
        return 0;
    }
    tm = TclpGetDate((TclpTime_t)&Start, 0);
    Month = 12 * (tm->tm_year + TM_YEAR_BASE) + tm->tm_mon + RelMonth;
    Year = Month / 12;
    Month = Month % 12 + 1;
    result = Convert(Month, (time_t) tm->tm_mday, Year,
	    (time_t) tm->tm_hour, (time_t) tm->tm_min, (time_t) tm->tm_sec,
	    MER24, DSTmaybe, &Julian);

    /*
     * The Julian time returned above is behind by one day, if "month" 
     * or "year" is used to specify relative time and the GMT flag is true.
     * This problem occurs only when the current time is closer to
     * midnight, the difference being not more than its time difference
     * with GMT. For example, in US/Pacific time zone, the problem occurs
     * whenever the current time is between midnight to 8:00am or 7:00amDST.
     * See Bug# 413397 for more details and sample script.
     * To resolve this bug, we simply add the number of seconds corresponding
     * to timezone difference with GMT to Julian time, if GMT flag is true.
     */

    if (TclDateTimezone == 0) {
        Julian += TclpGetTimeZone((unsigned long) Start) * 60L;
    }

    /*
     * The following iteration takes into account the case were we jump
     * into a "short month".  Far example, "one month from Jan 31" will
     * fail because there is no Feb 31.  The code below will reduce the
     * day and try converting the date until we succed or the date equals
     * 28 (which always works unless the date is bad in another way).
     */

    while ((result != 0) && (tm->tm_mday > 28)) {
	tm->tm_mday--;
	result = Convert(Month, (time_t) tm->tm_mday, Year,
		(time_t) tm->tm_hour, (time_t) tm->tm_min, (time_t) tm->tm_sec,
		MER24, DSTmaybe, &Julian);
    }
    if (result != 0) {
	return -1;
    }
    *TimePtr = DSTcorrect(Start, Julian);
    return 0;
}


/*
 *-----------------------------------------------------------------------------
 *
 * RelativeDay --
 *
 *      Given a starting time and a number of days before or after, compute the
 *      DST corrected difference between those dates.
 *
 * Results:
 *     1 or -1 indicating success or failure.
 *
 * Side effects:
 *      Fills TimePtr with the computed value.
 *
 *-----------------------------------------------------------------------------
 */

static int
RelativeDay(Start, RelDay, TimePtr)
    time_t Start;
    time_t RelDay;
    time_t *TimePtr;
{
    time_t new;

    new = Start + (RelDay * 60 * 60 * 24);
    *TimePtr = DSTcorrect(Start, new);
    return 1;
}

static int
LookupWord(buff)
    char                *buff;
{
    register char *p;
    register char *q;
    register TABLE *tp;
    int i;
    int abbrev;

    /*
     * Make it lowercase.
     */

    Tcl_UtfToLower(buff);

    if (strcmp(buff, "am") == 0 || strcmp(buff, "a.m.") == 0) {
        TclDatelval.Meridian = MERam;
        return tMERIDIAN;
    }
    if (strcmp(buff, "pm") == 0 || strcmp(buff, "p.m.") == 0) {
        TclDatelval.Meridian = MERpm;
        return tMERIDIAN;
    }

    /*
     * See if we have an abbreviation for a month.
     */
    if (strlen(buff) == 3) {
        abbrev = 1;
    } else if (strlen(buff) == 4 && buff[3] == '.') {
        abbrev = 1;
        buff[3] = '\0';
    } else {
        abbrev = 0;
    }

    for (tp = MonthDayTable; tp->name; tp++) {
        if (abbrev) {
            if (strncmp(buff, tp->name, 3) == 0) {
                TclDatelval.Number = tp->value;
                return tp->type;
            }
        } else if (strcmp(buff, tp->name) == 0) {
            TclDatelval.Number = tp->value;
            return tp->type;
        }
    }

    for (tp = TimezoneTable; tp->name; tp++) {
        if (strcmp(buff, tp->name) == 0) {
            TclDatelval.Number = tp->value;
            return tp->type;
        }
    }

    for (tp = UnitsTable; tp->name; tp++) {
        if (strcmp(buff, tp->name) == 0) {
            TclDatelval.Number = tp->value;
            return tp->type;
        }
    }

    /*
     * Strip off any plural and try the units table again.
     */
    i = strlen(buff) - 1;
    if (buff[i] == 's') {
        buff[i] = '\0';
        for (tp = UnitsTable; tp->name; tp++) {
            if (strcmp(buff, tp->name) == 0) {
                TclDatelval.Number = tp->value;
                return tp->type;
            }
	}
    }

    for (tp = OtherTable; tp->name; tp++) {
        if (strcmp(buff, tp->name) == 0) {
            TclDatelval.Number = tp->value;
            return tp->type;
        }
    }

    /*
     * Military timezones.
     */
    if (buff[1] == '\0' && !(*buff & 0x80)
	    && isalpha(UCHAR(*buff))) {	/* INTL: ISO only */
        for (tp = MilitaryTable; tp->name; tp++) {
            if (strcmp(buff, tp->name) == 0) {
                TclDatelval.Number = tp->value;
                return tp->type;
            }
	}
    }

    /*
     * Drop out any periods and try the timezone table again.
     */
    for (i = 0, p = q = buff; *q; q++)
        if (*q != '.') {
            *p++ = *q;
        } else {
            i++;
	}
    *p = '\0';
    if (i) {
        for (tp = TimezoneTable; tp->name; tp++) {
            if (strcmp(buff, tp->name) == 0) {
                TclDatelval.Number = tp->value;
                return tp->type;
            }
	}
    }
    
    return tID;
}


static int
TclDatelex()
{
    register char       c;
    register char       *p;
    char                buff[20];
    int                 Count;

    for ( ; ; ) {
        while (isspace(UCHAR(*TclDateInput))) {
            TclDateInput++;
	}

        if (isdigit(UCHAR(c = *TclDateInput))) { /* INTL: digit */
	    /* convert the string into a number; count the number of digits */
	    Count = 0;
            for (TclDatelval.Number = 0;
		    isdigit(UCHAR(c = *TclDateInput++)); ) { /* INTL: digit */
                TclDatelval.Number = 10 * TclDatelval.Number + c - '0';
		Count++;
	    }
            TclDateInput--;
	    /* A number with 6 or more digits is considered an ISO 8601 base */
	    if (Count >= 6) {
		return tISOBASE;
	    } else {
		return tUNUMBER;
	    }
        }
        if (!(c & 0x80) && isalpha(UCHAR(c))) {	/* INTL: ISO only. */
            for (p = buff; isalpha(UCHAR(c = *TclDateInput++)) /* INTL: ISO only. */
		     || c == '.'; ) {
                if (p < &buff[sizeof buff - 1]) {
                    *p++ = c;
		}
	    }
            *p = '\0';
            TclDateInput--;
            return LookupWord(buff);
        }
        if (c != '(') {
            return *TclDateInput++;
	}
        Count = 0;
        do {
            c = *TclDateInput++;
            if (c == '\0') {
                return c;
	    } else if (c == '(') {
                Count++;
	    } else if (c == ')') {
                Count--;
	    }
        } while (Count > 0);
    }
}

/*
 * Specify zone is of -50000 to force GMT.  (This allows BST to work).
 */

int
TclGetDate(p, now, zone, timePtr)
    char *p;
    unsigned long now;
    long zone;
    unsigned long *timePtr;
{
    struct tm *tm;
    time_t Start;
    time_t Time;
    time_t tod;
    int thisyear;

    TclDateInput = p;
    /* now has to be cast to a time_t for 64bit compliance */
    Start = now;
    tm = TclpGetDate((TclpTime_t) &Start, 0);
    thisyear = tm->tm_year + TM_YEAR_BASE;
    TclDateYear = thisyear;
    TclDateMonth = tm->tm_mon + 1;
    TclDateDay = tm->tm_mday;
    TclDateTimezone = zone;
    if (zone == -50000) {
        TclDateDSTmode = DSToff;  /* assume GMT */
        TclDateTimezone = 0;
    } else {
        TclDateDSTmode = DSTmaybe;
    }
    TclDateHour = 0;
    TclDateMinutes = 0;
    TclDateSeconds = 0;
    TclDateMeridian = MER24;
    TclDateRelSeconds = 0;
    TclDateRelMonth = 0;
    TclDateRelDay = 0;
    TclDateRelPointer = NULL;

    TclDateHaveDate = 0;
    TclDateHaveDay = 0;
    TclDateHaveOrdinalMonth = 0;
    TclDateHaveRel = 0;
    TclDateHaveTime = 0;
    TclDateHaveZone = 0;

    if (TclDateparse() || TclDateHaveTime > 1 || TclDateHaveZone > 1 || TclDateHaveDate > 1 ||
	    TclDateHaveDay > 1 || TclDateHaveOrdinalMonth > 1) {
        return -1;
    }
    
    if (TclDateHaveDate || TclDateHaveTime || TclDateHaveDay) {
	if (TclDateYear < 0) {
	    TclDateYear = -TclDateYear;
	}
	/*
	 * The following line handles years that are specified using
	 * only two digits.  The line of code below implements a policy
	 * defined by the X/Open workgroup on the millinium rollover.
	 * Note: some of those dates may not actually be valid on some
	 * platforms.  The POSIX standard startes that the dates 70-99
	 * shall refer to 1970-1999 and 00-38 shall refer to 2000-2038.
	 * This later definition should work on all platforms.
	 */

	if (TclDateYear < 100) {
	    if (TclDateYear >= 69) {
		TclDateYear += 1900;
	    } else {
		TclDateYear += 2000;
	    }
	}
	if (Convert(TclDateMonth, TclDateDay, TclDateYear, TclDateHour, TclDateMinutes, TclDateSeconds,
		TclDateMeridian, TclDateDSTmode, &Start) < 0) {
            return -1;
	}
    } else {
        Start = now;
        if (!TclDateHaveRel) {
            Start -= ((tm->tm_hour * 60L * 60L) +
		    tm->tm_min * 60L) +	tm->tm_sec;
	}
    }

    Start += TclDateRelSeconds;
    if (RelativeMonth(Start, TclDateRelMonth, &Time) < 0) {
        return -1;
    }
    Start += Time;

    if (RelativeDay(Start, TclDateRelDay, &Time) < 0) {
	return -1;
    }
    Start += Time;
    
    if (TclDateHaveDay && !TclDateHaveDate) {
        tod = NamedDay(Start, TclDateDayOrdinal, TclDateDayNumber);
        Start += tod;
    }

    if (TclDateHaveOrdinalMonth) {
	tod = NamedMonth(Start, TclDateMonthOrdinal, TclDateMonth);
	Start += tod;
    }
    
    *timePtr = Start;
    return 0;
}
static CONST TclDatetabelem TclDateexca[] ={