tclgetdate.y

linux系统下的音频通信

    { "idle",   tZONE,    -HOUR(12) },      /* International Date Line East */
    /* ADDED BY Marco Nijdam */
    { "dst",    tDST,     HOUR( 0) },       /* DST on (hour is ignored) */
    /* End ADDED */
    {  NULL  }
};

/*
 * Military timezone table.
 */
static TABLE    MilitaryTable[] = {
    { "a",      tZONE,  HOUR(  1) },
    { "b",      tZONE,  HOUR(  2) },
    { "c",      tZONE,  HOUR(  3) },
    { "d",      tZONE,  HOUR(  4) },
    { "e",      tZONE,  HOUR(  5) },
    { "f",      tZONE,  HOUR(  6) },
    { "g",      tZONE,  HOUR(  7) },
    { "h",      tZONE,  HOUR(  8) },
    { "i",      tZONE,  HOUR(  9) },
    { "k",      tZONE,  HOUR( 10) },
    { "l",      tZONE,  HOUR( 11) },
    { "m",      tZONE,  HOUR( 12) },
    { "n",      tZONE,  HOUR(- 1) },
    { "o",      tZONE,  HOUR(- 2) },
    { "p",      tZONE,  HOUR(- 3) },
    { "q",      tZONE,  HOUR(- 4) },
    { "r",      tZONE,  HOUR(- 5) },
    { "s",      tZONE,  HOUR(- 6) },
    { "t",      tZONE,  HOUR(- 7) },
    { "u",      tZONE,  HOUR(- 8) },
    { "v",      tZONE,  HOUR(- 9) },
    { "w",      tZONE,  HOUR(-10) },
    { "x",      tZONE,  HOUR(-11) },
    { "y",      tZONE,  HOUR(-12) },
    { "z",      tZONE,  HOUR(  0) },
    { NULL }
};


/*
 * Dump error messages in the bit bucket.
 */
static void
yyerror(s)
    char  *s;
{
}


static time_t
ToSeconds(Hours, Minutes, Seconds, Meridian)
    time_t      Hours;
    time_t      Minutes;
    time_t      Seconds;
    MERIDIAN    Meridian;
{
    if (Minutes < 0 || Minutes > 59 || Seconds < 0 || Seconds > 59)
        return -1;
    switch (Meridian) {
    case MER24:
        if (Hours < 0 || Hours > 23)
            return -1;
        return (Hours * 60L + Minutes) * 60L + Seconds;
    case MERam:
        if (Hours < 1 || Hours > 12)
            return -1;
        return ((Hours % 12) * 60L + Minutes) * 60L + Seconds;
    case MERpm:
        if (Hours < 1 || Hours > 12)
            return -1;
        return (((Hours % 12) + 12) * 60L + Minutes) * 60L + Seconds;
    }
    return -1;  /* Should never be reached */
}


static int
Convert(Month, Day, Year, Hours, Minutes, Seconds, Meridian, DSTmode, TimePtr)
    time_t      Month;
    time_t      Day;
    time_t      Year;
    time_t      Hours;
    time_t      Minutes;
    time_t      Seconds;
    MERIDIAN    Meridian;
    DSTMODE     DSTmode;
    time_t     *TimePtr;
{
    static int  DaysInMonth[12] = {
        31, 0, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
    };
    time_t tod;
    time_t Julian;
    int i;

    DaysInMonth[1] = Year % 4 == 0 && (Year % 100 != 0 || Year % 400 == 0)
                    ? 29 : 28;
    if (Month < 1 || Month > 12
     || Year < START_OF_TIME || Year > END_OF_TIME
     || Day < 1 || Day > DaysInMonth[(int)--Month])
        return -1;

    for (Julian = Day - 1, i = 0; i < Month; i++)
        Julian += DaysInMonth[i];
    if (Year >= EPOCH) {
        for (i = EPOCH; i < Year; i++)
            Julian += 365 + (i % 4 == 0);
    } else {
        for (i = Year; i < EPOCH; i++)
            Julian -= 365 + (i % 4 == 0);
    }
    Julian *= SECSPERDAY;
    Julian += yyTimezone * 60L;
    if ((tod = ToSeconds(Hours, Minutes, Seconds, Meridian)) < 0)
        return -1;
    Julian += tod;
    if (DSTmode == DSTon
     || (DSTmode == DSTmaybe && TclpGetDate(&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(&Start, 0)->tm_hour + 1) % 24;
    FutureDay = (TclpGetDate(&Future, 0)->tm_hour + 1) % 24;
    return (Future - Start) + (StartDay - FutureDay) * 60L * 60L;
}


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

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


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

    /*
     * Make it lowercase.
     */
    for (p = buff; *p; p++) {
        if (isupper(UCHAR(*p))) {
            *p = (char) tolower(UCHAR(*p));
	}
    }

    if (strcmp(buff, "am") == 0 || strcmp(buff, "a.m.") == 0) {
        yylval.Meridian = MERam;
        return tMERIDIAN;
    }
    if (strcmp(buff, "pm") == 0 || strcmp(buff, "p.m.") == 0) {
        yylval.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) {
                yylval.Number = tp->value;
                return tp->type;
            }
        } else if (strcmp(buff, tp->name) == 0) {
            yylval.Number = tp->value;
            return tp->type;
        }
    }

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

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

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

    /*
     * Military timezones.
     */
    if (buff[1] == '\0' && isalpha(UCHAR(*buff))) {
        for (tp = MilitaryTable; tp->name; tp++) {
            if (strcmp(buff, tp->name) == 0) {
                yylval.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) {
                yylval.Number = tp->value;
                return tp->type;
            }
	}
    }
    
    return tID;
}


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

    for ( ; ; ) {
        while (isspace((unsigned char) (*yyInput))) {
            yyInput++;
	}

        if (isdigit(c = *yyInput) || c == '-' || c == '+') {
            if (c == '-' || c == '+') {
                sign = c == '-' ? -1 : 1;
                if (!isdigit(*++yyInput)) {
                    /*
		     * skip the '-' sign
		     */
                    continue;
		}
            } else {
                sign = 0;
	    }
            for (yylval.Number = 0; isdigit(c = *yyInput++); ) {
                yylval.Number = 10 * yylval.Number + c - '0';
	    }
            yyInput--;
            if (sign < 0) {
                yylval.Number = -yylval.Number;
	    }
            return sign ? tSNUMBER : tUNUMBER;
        }
        if (isalpha(UCHAR(c))) {
            for (p = buff; isalpha(c = *yyInput++) || c == '.'; ) {
                if (p < &buff[sizeof buff - 1]) {
                    *p++ = c;
		}
	    }
            *p = '\0';
            yyInput--;
            return LookupWord(buff);
        }
        if (c != '(') {
            return *yyInput++;
	}
        Count = 0;
        do {
            c = *yyInput++;
            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;

    yyInput = p;
    tm = TclpGetDate((time_t *) &now, 0);
    thisyear = tm->tm_year + TM_YEAR_BASE;
    yyYear = thisyear;
    yyMonth = tm->tm_mon + 1;
    yyDay = tm->tm_mday;
    yyTimezone = zone;
    if (zone == -50000) {
        yyDSTmode = DSToff;  /* assume GMT */
        yyTimezone = 0;
    } else {
        yyDSTmode = DSTmaybe;
    }
    yyHour = 0;
    yyMinutes = 0;
    yySeconds = 0;
    yyMeridian = MER24;
    yyRelSeconds = 0;
    yyRelMonth = 0;
    yyHaveDate = 0;
    yyHaveDay = 0;
    yyHaveRel = 0;
    yyHaveTime = 0;
    yyHaveZone = 0;

    if (yyparse() || yyHaveTime > 1 || yyHaveZone > 1 || yyHaveDate > 1 ||
	    yyHaveDay > 1) {
        return -1;
    }
    
    if (yyHaveDate || yyHaveTime || yyHaveDay) {
	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(yyMonth, yyDay, yyYear, yyHour, yyMinutes, yySeconds,
		yyMeridian, yyDSTmode, &Start) < 0) {
            return -1;
	}
    } else {
        Start = now;
        if (!yyHaveRel) {
            Start -= ((tm->tm_hour * 60L) + tm->tm_min * 60L) + tm->tm_sec;
	}
    }

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

    if (yyHaveDay && !yyHaveDate) {
        tod = RelativeDate(Start, yyDayOrdinal, yyDayNumber);
        Start += tod;
    }

    *timePtr = Start;
    return 0;
}