path: root/lib/getdate.y

%{
/*
**  Originally written by Steven M. Bellovin <smb@research.att.com> while
**  at the University of North Carolina at Chapel Hill.  Later tweaked by
**  a couple of people on Usenet.  Completely overhauled by Rich $alz
**  <rsalz@bbn.com> and Jim Berets <jberets@bbn.com> in August, 1990;
**  send any email to Rich.
**
**  This grammar has 10 shift/reduce conflicts.
**
**  This code is in the public domain and has no copyright.
*/
/* SUPPRESS 287 on yaccpar_sccsid *//* Unused static variable */
/* SUPPRESS 288 on yyerrlab *//* Label unused */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

/* Since the code of getdate.y is not included in the Emacs executable
   itself, there is no need to #define static in this file.  Even if
   the code were included in the Emacs executable, it probably
   wouldn't do any harm to #undef it here; this will only cause
   problems if we try to write to a static variable, which I don't
   think this code needs to do.  */
#ifdef emacs
#undef static
#endif

#include <stdio.h>
#include <ctype.h>

#if	defined (vms)
#include <types.h>
#include <time.h>
#else
#include <sys/types.h>
#ifdef TIME_WITH_SYS_TIME
#include <sys/time.h>
#include <time.h>
#else
#ifdef HAVE_SYS_TIME_H
#include <sys/time.h>
#else
#include <time.h>
#endif
#endif

#ifdef timezone
#undef timezone /* needed for sgi */
#endif

#if defined (HAVE_SYS_TIMEB_H)
#include <sys/timeb.h>
#else

/* get_date uses the obsolete `struct timeb' in its interface!  FIXME.
   Since some systems don't have it, we define it here;
   callers must do likewise.  */
struct timeb
  {
    time_t		time;		/* Seconds since the epoch	*/
    unsigned short	millitm;	/* Field not used		*/
    short		timezone;	/* Minutes west of GMT		*/
    short		dstflag;	/* Field not used		*/
};
#endif /* defined (HAVE_SYS_TIMEB_H) */

#endif	/* defined (vms) */

#if defined (STDC_HEADERS) || defined (USG)
#include <string.h>
#endif

/* Some old versions of bison generate parsers that use bcopy.
   That loses on systems that don't provide the function, so we have
   to redefine it here.  */
#if !defined (HAVE_BCOPY) && defined (HAVE_MEMCPY) && !defined (bcopy)
#define bcopy(from, to, len) memcpy ((to), (from), (len))
#endif

extern struct tm	*gmtime ();
extern struct tm	*localtime ();

#define yyparse getdate_yyparse
#define yylex getdate_yylex
#define yyerror getdate_yyerror

static int yylex ();
static int yyerror ();

#define EPOCH		1970
#define HOUR(x)		((time_t)(x) * 60)
#define SECSPERDAY	(24L * 60L * 60L)

#define MAX_BUFF_LEN    128   /* size of buffer to read the date into */

/*
**  An entry in the lexical lookup table.
*/
typedef struct _TABLE {
    const char	*name;
    int		type;
    time_t	value;
} TABLE;


/*
**  Daylight-savings mode:  on, off, or not yet known.
*/
typedef enum _DSTMODE {
    DSTon, DSToff, DSTmaybe
} DSTMODE;

/*
**  Meridian:  am, pm, or 24-hour style.
*/
typedef enum _MERIDIAN {
    MERam, MERpm, MER24
} MERIDIAN;


/*
**  Global variables.  We could get rid of most of these by using a good
**  union as the yacc stack.  (This routine was originally written before
**  yacc had the %union construct.)  Maybe someday; right now we only use
**  the %union very rarely.
*/
static char	*yyInput;
static DSTMODE	yyDSTmode;
static time_t	yyDayOrdinal;
static time_t	yyDayNumber;
static int	yyHaveDate;
static int	yyHaveDay;
static int	yyHaveRel;
static int	yyHaveTime;
static int	yyHaveZone;
static time_t	yyTimezone;
static time_t	yyDay;
static time_t	yyHour;
static time_t	yyMinutes;
static time_t	yyMonth;
static time_t	yySeconds;
static time_t	yyYear;
static MERIDIAN	yyMeridian;
static time_t	yyRelMonth;
static time_t	yyRelSeconds;

%}

%union {
    time_t		Number;
    enum _MERIDIAN	Meridian;
}

%token	tAGO tDAY tDAYZONE tID tMERIDIAN tMINUTE_UNIT tMONTH tMONTH_UNIT
%token	tSEC_UNIT tSNUMBER tUNUMBER tZONE tDST

%type	<Number>	tDAY tDAYZONE tMINUTE_UNIT tMONTH tMONTH_UNIT
%type	<Number>	tSEC_UNIT tSNUMBER tUNUMBER tZONE
%type	<Meridian>	tMERIDIAN o_merid

%%

spec	: /* NULL */
	| spec item
	;

item	: time {
	    yyHaveTime++;
	}
	| zone {
	    yyHaveZone++;
	}
	| date {
	    yyHaveDate++;
	}
	| day {
	    yyHaveDay++;
	}
	| rel {
	    yyHaveRel++;
	}
	| number
	;

time	: tUNUMBER tMERIDIAN {
	    yyHour = $1;
	    yyMinutes = 0;
	    yySeconds = 0;
	    yyMeridian = $2;
	}
	| tUNUMBER ':' tUNUMBER o_merid {
	    yyHour = $1;
	    yyMinutes = $3;
	    yySeconds = 0;
	    yyMeridian = $4;
	}
	| tUNUMBER ':' tUNUMBER tSNUMBER {
	    yyHour = $1;
	    yyMinutes = $3;
	    yyMeridian = MER24;
	    yyDSTmode = DSToff;
	    yyTimezone = - ($4 % 100 + ($4 / 100) * 60);
	}
	| tUNUMBER ':' tUNUMBER ':' tUNUMBER o_merid {
	    yyHour = $1;
	    yyMinutes = $3;
	    yySeconds = $5;
	    yyMeridian = $6;
	}
	| tUNUMBER ':' tUNUMBER ':' tUNUMBER tSNUMBER {
	    yyHour = $1;
	    yyMinutes = $3;
	    yySeconds = $5;
	    yyMeridian = MER24;
	    yyDSTmode = DSToff;
	    yyTimezone = - ($6 % 100 + ($6 / 100) * 60);
	}
	;

zone	: tZONE {
	    yyTimezone = $1;
	    yyDSTmode = DSToff;
	}
	| tDAYZONE {
	    yyTimezone = $1;
	    yyDSTmode = DSTon;
	}
	|
	  tZONE tDST {
	    yyTimezone = $1;
	    yyDSTmode = DSTon;
	}
	;

day	: tDAY {
	    yyDayOrdinal = 1;
	    yyDayNumber = $1;
	}
	| tDAY ',' {
	    yyDayOrdinal = 1;
	    yyDayNumber = $1;
	}
	| tUNUMBER tDAY {
	    yyDayOrdinal = $1;
	    yyDayNumber = $2;
	}
	;

date	: tUNUMBER '/' tUNUMBER {
	    yyMonth = $1;
	    yyDay = $3;
	}
	| tUNUMBER '/' tUNUMBER '/' tUNUMBER {
	    yyMonth = $1;
	    yyDay = $3;
	    yyYear = $5;
	}
	| tUNUMBER tSNUMBER tSNUMBER {
	    /* ISO 8601 format.  yyyy-mm-dd.  */
	    yyYear = $1;
	    yyMonth = -$2;
	    yyDay = -$3;
	}
	| tUNUMBER tMONTH tSNUMBER {
	    /* e.g. 17-JUN-1992.  */
	    yyDay = $1;
	    yyMonth = $2;
	    yyYear = -$3;
	}
	| tMONTH tUNUMBER {
	    yyMonth = $1;
	    yyDay = $2;
	}
	| tMONTH tUNUMBER ',' tUNUMBER {
	    yyMonth = $1;
	    yyDay = $2;
	    yyYear = $4;
	}
	| tUNUMBER tMONTH {
	    yyMonth = $2;
	    yyDay = $1;
	}
	| tUNUMBER tMONTH tUNUMBER {
	    yyMonth = $2;
	    yyDay = $1;
	    yyYear = $3;
	}
	;

rel	: relunit tAGO {
	    yyRelSeconds = -yyRelSeconds;
	    yyRelMonth = -yyRelMonth;
	}
	| relunit
	;

relunit	: tUNUMBER tMINUTE_UNIT {
	    yyRelSeconds += $1 * $2 * 60L;
	}
	| tSNUMBER tMINUTE_UNIT {
	    yyRelSeconds += $1 * $2 * 60L;
	}
	| tMINUTE_UNIT {
	    yyRelSeconds += $1 * 60L;
	}
	| tSNUMBER tSEC_UNIT {
	    yyRelSeconds += $1;
	}
	| tUNUMBER tSEC_UNIT {
	    yyRelSeconds += $1;
	}
	| tSEC_UNIT {
	    yyRelSeconds++;
	}
	| tSNUMBER tMONTH_UNIT {
	    yyRelMonth += $1 * $2;
	}
	| tUNUMBER tMONTH_UNIT {
	    yyRelMonth += $1 * $2;
	}
	| tMONTH_UNIT {
	    yyRelMonth += $1;
	}
	;

number	: tUNUMBER {
	    if (yyHaveTime && yyHaveDate && !yyHaveRel)
		yyYear = $1;
	    else {
		if ($1>10000) {
		    yyHaveDate++;
		    yyDay= ($1)%100;
		    yyMonth= ($1/100)%100;
		    yyYear = $1/10000;
		}
		else {
		    yyHaveTime++;
		    if ($1 < 100) {
			yyHour = $1;
			yyMinutes = 0;
		    }
		    else {
		    	yyHour = $1 / 100;
		    	yyMinutes = $1 % 100;
		    }
		    yySeconds = 0;
		    yyMeridian = MER24;
	        }
	    }
	}
	;

o_merid	: /* NULL */ {
	    $$ = MER24;
	}
	| tMERIDIAN {
	    $$ = $1;
	}
	;

%%

/* Month and day table. */
static TABLE const MonthDayTable[] = {
    { "january",	tMONTH,  1 },
    { "february",	tMONTH,  2 },
    { "march",		tMONTH,  3 },
    { "april",		tMONTH,  4 },
    { "may",		tMONTH,  5 },
    { "june",		tMONTH,  6 },
    { "july",		tMONTH,  7 },
    { "august",		tMONTH,  8 },
    { "september",	tMONTH,  9 },
    { "sept",		tMONTH,  9 },
    { "october",	tMONTH, 10 },
    { "november",	tMONTH, 11 },
    { "december",	tMONTH, 12 },
    { "sunday",		tDAY, 0 },
    { "monday",		tDAY, 1 },
    { "tuesday",	tDAY, 2 },
    { "tues",		tDAY, 2 },
    { "wednesday",	tDAY, 3 },
    { "wednes",		tDAY, 3 },
    { "thursday",	tDAY, 4 },
    { "thur",		tDAY, 4 },
    { "thurs",		tDAY, 4 },
    { "friday",		tDAY, 5 },
    { "saturday",	tDAY, 6 },
    { NULL }
};

/* Time units table. */
static TABLE const UnitsTable[] = {
    { "year",		tMONTH_UNIT,	12 },
    { "month",		tMONTH_UNIT,	1 },
    { "fortnight",	tMINUTE_UNIT,	14 * 24 * 60 },
    { "week",		tMINUTE_UNIT,	7 * 24 * 60 },
    { "day",		tMINUTE_UNIT,	1 * 24 * 60 },
    { "hour",		tMINUTE_UNIT,	60 },
    { "minute",		tMINUTE_UNIT,	1 },
    { "min",		tMINUTE_UNIT,	1 },
    { "second",		tSEC_UNIT,	1 },
    { "sec",		tSEC_UNIT,	1 },
    { NULL }
};

/* Assorted relative-time words. */
static TABLE const OtherTable[] = {
    { "tomorrow",	tMINUTE_UNIT,	1 * 24 * 60 },
    { "yesterday",	tMINUTE_UNIT,	-1 * 24 * 60 },
    { "today",		tMINUTE_UNIT,	0 },
    { "now",		tMINUTE_UNIT,	0 },
    { "last",		tUNUMBER,	-1 },
    { "this",		tMINUTE_UNIT,	0 },
    { "next",		tUNUMBER,	2 },
    { "first",		tUNUMBER,	1 },
/*  { "second",		tUNUMBER,	2 }, */
    { "third",		tUNUMBER,	3 },
    { "fourth",		tUNUMBER,	4 },
    { "fifth",		tUNUMBER,	5 },
    { "sixth",		tUNUMBER,	6 },
    { "seventh",	tUNUMBER,	7 },
    { "eighth",		tUNUMBER,	8 },
    { "ninth",		tUNUMBER,	9 },
    { "tenth",		tUNUMBER,	10 },
    { "eleventh",	tUNUMBER,	11 },
    { "twelfth",	tUNUMBER,	12 },
    { "ago",		tAGO,	1 },
    { NULL }
};

/* The timezone table. */
/* Some of these are commented out because a time_t can't store a float. */
static TABLE const TimezoneTable[] = {
    { "gmt",	tZONE,     HOUR ( 0) },	/* Greenwich Mean */
    { "ut",	tZONE,     HOUR ( 0) },	/* Universal (Coordinated) */
    { "utc",	tZONE,     HOUR ( 0) },
    { "wet",	tZONE,     HOUR ( 0) },	/* Western European */
    { "bst",	tDAYZONE,  HOUR ( 0) },	/* British Summer */
    { "wat",	tZONE,     HOUR ( 1) },	/* West Africa */
    { "at",	tZONE,     HOUR ( 2) },	/* Azores */
#if	0
    /* For completeness.  BST is also British Summer, and GST is
     * also Guam Standard. */
    { "bst",	tZONE,     HOUR ( 3) },	/* Brazil Standard */
    { "gst",	tZONE,     HOUR ( 3) },	/* Greenland Standard */
#endif
#if 0
    { "nft",	tZONE,     HOUR (3.5) },	/* Newfoundland */
    { "nst",	tZONE,     HOUR (3.5) },	/* Newfoundland Standard */
    { "ndt",	tDAYZONE,  HOUR (3.5) },	/* Newfoundland Daylight */
#endif
    { "ast",	tZONE,     HOUR ( 4) },	/* Atlantic Standard */
    { "adt",	tDAYZONE,  HOUR ( 4) },	/* Atlantic Daylight */
    { "est",	tZONE,     HOUR ( 5) },	/* Eastern Standard */
    { "edt",	tDAYZONE,  HOUR ( 5) },	/* Eastern Daylight */
    { "cst",	tZONE,     HOUR ( 6) },	/* Central Standard */
    { "cdt",	tDAYZONE,  HOUR ( 6) },	/* Central Daylight */
    { "mst",	tZONE,     HOUR ( 7) },	/* Mountain Standard */
    { "mdt",	tDAYZONE,  HOUR ( 7) },	/* Mountain Daylight */
    { "pst",	tZONE,     HOUR ( 8) },	/* Pacific Standard */
    { "pdt",	tDAYZONE,  HOUR ( 8) },	/* Pacific Daylight */
    { "yst",	tZONE,     HOUR ( 9) },	/* Yukon Standard */
    { "ydt",	tDAYZONE,  HOUR ( 9) },	/* Yukon Daylight */
    { "hst",	tZONE,     HOUR (10) },	/* Hawaii Standard */
    { "hdt",	tDAYZONE,  HOUR (10) },	/* Hawaii Daylight */
    { "cat",	tZONE,     HOUR (10) },	/* Central Alaska */
    { "ahst",	tZONE,     HOUR (10) },	/* Alaska-Hawaii Standard */
    { "nt",	tZONE,     HOUR (11) },	/* Nome */
    { "idlw",	tZONE,     HOUR (12) },	/* International Date Line West */
    { "cet",	tZONE,     -HOUR (1) },	/* Central European */
    { "met",	tZONE,     -HOUR (1) },	/* Middle European */
    { "mewt",	tZONE,     -HOUR (1) },	/* Middle European Winter */
    { "mest",	tDAYZONE,  -HOUR (1) },	/* Middle European Summer */
    { "mesz",	tDAYZONE,  -HOUR (1) },	/* Middle European Summer */
    { "swt",	tZONE,     -HOUR (1) },	/* Swedish Winter */
    { "sst",	tDAYZONE,  -HOUR (1) },	/* Swedish Summer */
    { "fwt",	tZONE,     -HOUR (1) },	/* French Winter */
    { "fst",	tDAYZONE,  -HOUR (1) },	/* French Summer */
    { "eet",	tZONE,     -HOUR (2) },	/* Eastern Europe, USSR Zone 1 */
    { "bt",	tZONE,     -HOUR (3) },	/* Baghdad, USSR Zone 2 */
#if 0
    { "it",	tZONE,     -HOUR (3.5) },/* Iran */
#endif
    { "zp4",	tZONE,     -HOUR (4) },	/* USSR Zone 3 */
    { "zp5",	tZONE,     -HOUR (5) },	/* USSR Zone 4 */
#if 0
    { "ist",	tZONE,     -HOUR (5.5) },/* Indian Standard */
#endif
    { "zp6",	tZONE,     -HOUR (6) },	/* USSR Zone 5 */
#if	0
    /* For completeness.  NST is also Newfoundland Standard, and 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 */
#if 0
    { "jt",	tZONE,     -HOUR (7.5) },/* Java (3pm in Cronusland!) */
#endif
    { "cct",	tZONE,     -HOUR (8) },	/* China Coast, USSR Zone 7 */
    { "jst",	tZONE,     -HOUR (9) },	/* Japan Standard, USSR Zone 8 */
#if 0
    { "cast",	tZONE,     -HOUR (9.5) },/* Central Australian Standard */
    { "cadt",	tDAYZONE,  -HOUR (9.5) },/* Central Australian Daylight */
#endif
    { "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 const 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 */
static 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;
    if (Hours == 12)
      Hours = 0;
    return (Hours * 60L + Minutes) * 60L + Seconds;
  case MERpm:
    if (Hours < 1 || Hours > 12)
      return -1;
    if (Hours == 12)
      Hours = 0;
    return ((Hours + 12) * 60L + Minutes) * 60L + Seconds;
  default:
    abort ();
  }
  /* 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 > 2037
      || 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 const 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;
    }

  if (strcmp (buff, "dst") == 0) 
    return tDST;

  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;
}


static 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);
  }
}

#define TM_YEAR_ORIGIN 1900

/* Yield A - B, measured in seconds.  */
static long
difftm (a, b)
     struct tm *a, *b;
{
  int ay = a->tm_year + (TM_YEAR_ORIGIN - 1);
  int by = b->tm_year + (TM_YEAR_ORIGIN - 1);
  long days = (
	       /* difference in day of year */
	       a->tm_yday - b->tm_yday
	       /* + intervening leap days */
	       +  ((ay >> 2) - (by >> 2))
	       -  (ay/100 - by/100)
	       +  ((ay/100 >> 2) - (by/100 >> 2))
	       /* + difference in years * 365 */
	       +  (long)(ay-by) * 365
	       );
  return (60*(60*(24*days + (a->tm_hour - b->tm_hour))
	      + (a->tm_min - b->tm_min))
	  + (a->tm_sec - b->tm_sec));
}

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

  yyInput = p;
  if (now == NULL) {
    now = &ftz;
    (void)time (&ftz.time);

    if (! (tm = gmtime (&ftz.time)))
      return -1;
    gmt = *tm;			/* Make a copy, in case localtime modifies *tm.  */

    if (! (tm = localtime (&ftz.time)))
      return -1;
	
    ftz.timezone = difftm (&gmt, tm) / 60;
    if (tm->tm_isdst)
      ftz.timezone += 60;
  }

  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 */
int
main (ac, av)
    int		ac;
    char	*av[];
{
  char buff[MAX_BUFF_LEN + 1];
  time_t d;

  (void)printf ("Enter date, or blank line to exit.\n\t> ");
  (void)fflush (stdout);

  buff[MAX_BUFF_LEN] = 0;
  while (fgets (buff, MAX_BUFF_LEN, stdin) && 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) */