getdate.y

unix 下tar 执行程序的源代码

    { "zp5",	tZONE,     -HOUR(5) },	/* USSR Zone 4 */
    { "ist",	tZONE,     -HOUR(5.5) },/* Indian Standard */
    { "zp6",	tZONE,     -HOUR(6) },	/* USSR Zone 5 */
#if	0
    /* For completeness.  NST is also Newfoundland Stanard, nad SST is
     * also Swedish Summer. */
    { "nst",	tZONE,     -HOUR(6.5) },/* North Sumatra */
    { "sst",	tZONE,     -HOUR(7) },	/* South Sumatra, USSR Zone 6 */
#endif	/* 0 */
    { "wast",	tZONE,     -HOUR(7) },	/* West Australian Standard */
    { "wadt",	tDAYZONE,  -HOUR(7) },	/* West Australian Daylight */
    { "jt",	tZONE,     -HOUR(7.5) },/* Java (3pm in Cronusland!) */
    { "cct",	tZONE,     -HOUR(8) },	/* China Coast, USSR Zone 7 */
    { "jst",	tZONE,     -HOUR(9) },	/* Japan Standard, USSR Zone 8 */
    { "cast",	tZONE,     -HOUR(9.5) },/* Central Australian Standard */
    { "cadt",	tDAYZONE,  -HOUR(9.5) },/* Central Australian Daylight */
    { "east",	tZONE,     -HOUR(10) },	/* Eastern Australian Standard */
    { "eadt",	tDAYZONE,  -HOUR(10) },	/* Eastern Australian Daylight */
    { "gst",	tZONE,     -HOUR(10) },	/* Guam Standard, USSR Zone 9 */
    { "nzt",	tZONE,     -HOUR(12) },	/* New Zealand */
    { "nzst",	tZONE,     -HOUR(12) },	/* New Zealand Standard */
    { "nzdt",	tDAYZONE,  -HOUR(12) },	/* New Zealand Daylight */
    { "idle",	tZONE,     -HOUR(12) },	/* International Date Line East */
    {  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 }
};




/* ARGSUSED */
int
yyerror(s)
    char	*s;
{
  return 0;
}


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 * 60L + Minutes) * 60L + Seconds;
    case MERpm:
	if (Hours < 1 || Hours > 12)
	    return -1;
	return ((Hours + 12) * 60L + Minutes) * 60L + Seconds;
    }
    /* NOTREACHED */
}


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

    if (Year < 0)
	Year = -Year;
    if (Year < 100)
	Year += 1900;
    DaysInMonth[1] = Year % 4 == 0 && (Year % 100 != 0 || Year % 400 == 0)
		    ? 29 : 28;
    if (Year < EPOCH || Year > 1999
     || Month < 1 || Month > 12
     /* Lint fluff:  "conversion from long may lose accuracy" */
     || Day < 1 || Day > DaysInMonth[(int)--Month])
	return -1;

    for (Julian = Day - 1, i = 0; i < Month; i++)
	Julian += DaysInMonth[i];
    for (i = EPOCH; i < Year; 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 && localtime(&Julian)->tm_isdst))
	Julian -= 60 * 60;
    return Julian;
}


static time_t
DSTcorrect(Start, Future)
    time_t	Start;
    time_t	Future;
{
    time_t	StartDay;
    time_t	FutureDay;

    StartDay = (localtime(&Start)->tm_hour + 1) % 24;
    FutureDay = (localtime(&Future)->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 = localtime(&now);
    now += SECSPERDAY * ((DayNumber - tm->tm_wday + 7) % 7);
    now += 7 * SECSPERDAY * (DayOrdinal <= 0 ? DayOrdinal : DayOrdinal - 1);
    return DSTcorrect(Start, now);
}


static time_t
RelativeMonth(Start, RelMonth)
    time_t	Start;
    time_t	RelMonth;
{
    struct tm	*tm;
    time_t	Month;
    time_t	Year;

    if (RelMonth == 0)
	return 0;
    tm = localtime(&Start);
    Month = 12 * tm->tm_year + tm->tm_mon + RelMonth;
    Year = Month / 12;
    Month = Month % 12 + 1;
    return DSTcorrect(Start,
	    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));
}


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(*p))
	    *p = tolower(*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;
	    }
	buff[i] = 's';		/* Put back for "this" in OtherTable. */
    }

    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(*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;
}


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

    for ( ; ; ) {
	while (isspace(*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(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;
	    if (c == '(')
		Count++;
	    else if (c == ')')
		Count--;
	} while (Count > 0);
    }
}


time_t
get_date(p, now)
    char		*p;
    struct timeb	*now;
{
    struct tm		*tm;
    struct timeb	ftz;
    time_t		Start;
    time_t		tod;

    yyInput = p;
    if (now == NULL) {
	now = &ftz;
#if	defined(NEED_TZSET)
	(void)time(&ftz.time);
	/* Set the timezone global. */
	tzset();
	ftz.timezone = (int) timezone / 60;
#else
	(void)ftime(&ftz);
#endif	/* defined(NEED_TZSET) */
    }

    tm = localtime(&now->time);
    yyYear = tm->tm_year;
    yyMonth = tm->tm_mon + 1;
    yyDay = tm->tm_mday;
    yyTimezone = now->timezone;
    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) {
	Start = Convert(yyMonth, yyDay, yyYear, yyHour, yyMinutes, yySeconds,
		    yyMeridian, yyDSTmode);
	if (Start < 0)
	    return -1;
    }
    else {
	Start = now->time;
	if (!yyHaveRel)
	    Start -= ((tm->tm_hour * 60L + tm->tm_min) * 60L) + tm->tm_sec;
    }

    Start += yyRelSeconds;
    Start += RelativeMonth(Start, yyRelMonth);

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

    /* Have to do *something* with a legitimate -1 so it's distinguishable
     * from the error return value.  (Alternately could set errno on error.) */
    return Start == -1 ? 0 : Start;
}


#if	defined(TEST)

/* ARGSUSED */
main(ac, av)
    int		ac;
    char	*av[];
{
    char	buff[128];
    time_t	d;

    (void)printf("Enter date, or blank line to exit.\n\t> ");
    (void)fflush(stdout);
    while (gets(buff) && buff[0]) {
	d = get_date(buff, (struct timeb *)NULL);
	if (d == -1)
	    (void)printf("Bad format - couldn't convert.\n");
	else
	    (void)printf("%s", ctime(&d));
	(void)printf("\t> ");
	(void)fflush(stdout);
    }
    exit(0);
    /* NOTREACHED */
}
#endif	/* defined(TEST) */