mixmaster

parsedate.y (23910B)

---

 %{
 /*  $Id: parsedate.y 647 2003-10-25 23:34:13Z weasel $
 **
 **  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@osf.org> and Jim Berets <jberets@bbn.com> in August, 1990.
 **  Further revised (removed obsolete constructs and cleaned up timezone
 **  names) in August, 1991, by Rich.  Paul Eggert <eggert@twinsun.com>
 **  helped in September, 1992.
 **
 **  This grammar has six shift/reduce conflicts.
 **
 **  This code is in the public domain and has no copyright.
 */
 
 #include <stdio.h>
 #include <string.h>
 
 // #include "config.h"
 // #include "clibrary.h"
 #include <ctype.h>
 
 #if defined(_HPUX_SOURCE)
 # include <alloca.h>
 #endif
 
 #ifdef TM_IN_SYS_TIME
 # include <sys/time.h>
 #else
 # include <time.h>
 #endif
 
 // #include "libinn.h"
 
 /* Used for iterating through arrays.  ARRAY_SIZE returns the number of
    elements in the array (useful for a < upper bound in a for loop) and
    ARRAY_END returns a pointer to the element past the end (ISO C99 makes it
    legal to refer to such a pointer as long as it's never dereferenced). */
 #define ARRAY_SIZE(array)       (sizeof(array) / sizeof((array)[0]))
 #define ARRAY_END(array)        (&(array)[ARRAY_SIZE(array)])
 
 /* On some systems, the macros defined by <ctype.h> are only vaild on ASCII
    characters (those characters that isascii() says are ASCII).  This comes
    into play when applying <ctype.h> macros to eight-bit data.  autoconf
    checks for this with as part of AC_HEADER_STDC, so if autoconf doesn't
    think our headers are standard, check isascii() first. */
 #if STDC_HEADERS
 # define CTYPE(isXXXXX, c) (isXXXXX((unsigned char)(c)))
 #else
 # define CTYPE(isXXXXX, c) \
     (isascii((unsigned char)(c)) && isXXXXX((unsigned char)(c)))
 #endif
 
 
 #define yylhs		date_yylhs
 #define yylen		date_yylen
 #define yydefred	date_yydefred
 #define yydgoto		date_yydgoto
 #define yysindex	date_yysindex
 #define yyrindex	date_yyrindex
 #define yygindex	date_yygindex
 #define yytable		date_yytable
 #define yycheck		date_yycheck
 #define yyparse		date_parse
 #define yylex		date_lex
 #define yyerror		date_error
 #define yymaxdepth	date_yymaxdepth
 
 
 static int date_lex(void);
 
 
     /* See the LeapYears table in Convert. */
 #define EPOCH		1970
 #define END_OF_TIME	2038
     /* Constants for general time calculations. */
 #define DST_OFFSET	1
 #define SECSPERDAY	(24L * 60L * 60L)
     /* Readability for TABLE stuff. */
 #define HOUR(x)		(x * 60)
 
 #define LPAREN		'('
 #define RPAREN		')'
 #define IS7BIT(x)	((unsigned int)(x) < 0200)
 
 
 /*
 **  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 them by using a yacc
 **  union, but this is more efficient.  (This routine predates the
 **  yacc %union construct.)
 */
 static char	*yyInput;
 static DSTMODE	yyDSTmode;
 static int	yyHaveDate;
 static int	yyHaveRel;
 static int	yyHaveTime;
 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;
 
 
 /* extern struct tm	*localtime(); */
 
 static void		date_error(const char *s);
 %}
 
 %union {
     time_t		Number;
     enum _MERIDIAN	Meridian;
 }
 
 %token	tDAY tDAYZONE tMERIDIAN tMONTH tMONTH_UNIT tSEC_UNIT tSNUMBER
 %token	tUNUMBER tZONE
 
 %type	<Number>	tDAYZONE tMONTH tMONTH_UNIT tSEC_UNIT
 %type	<Number>	tSNUMBER tUNUMBER tZONE numzone zone
 %type	<Meridian>	tMERIDIAN o_merid
 
 %%
 
 spec	: /* NULL */
 	| spec item
 	;
 
 item	: time {
 	    yyHaveTime++;
 #if	defined(lint)
 	    /* I am compulsive about lint natterings... */
 	    if (yyHaveTime == -1) {
 		YYERROR;
 	    }
 #endif	/* defined(lint) */
 	}
 	| time zone {
 	    yyHaveTime++;
 	    yyTimezone = $2;
 	}
 	| date {
 	    yyHaveDate++;
 	}
 	| rel {
 	    yyHaveRel = 1;
 	}
 	;
 
 time	: tUNUMBER o_merid {
 	    if ($1 < 100) {
 		yyHour = $1;
 		yyMinutes = 0;
 	    }
 	    else {
 		yyHour = $1 / 100;
 		yyMinutes = $1 % 100;
 	    }
 	    yySeconds = 0;
 	    yyMeridian = $2;
 	}
 	| tUNUMBER ':' tUNUMBER o_merid {
 	    yyHour = $1;
 	    yyMinutes = $3;
 	    yySeconds = 0;
 	    yyMeridian = $4;
 	}
 	| tUNUMBER ':' tUNUMBER numzone {
 	    yyHour = $1;
 	    yyMinutes = $3;
 	    yyTimezone = $4;
 	    yyMeridian = MER24;
 	    yyDSTmode = DSToff;
 	}
 	| tUNUMBER ':' tUNUMBER ':' tUNUMBER o_merid {
 	    yyHour = $1;
 	    yyMinutes = $3;
 	    yySeconds = $5;
 	    yyMeridian = $6;
 	}
 	| tUNUMBER ':' tUNUMBER ':' tUNUMBER numzone {
 	    yyHour = $1;
 	    yyMinutes = $3;
 	    yySeconds = $5;
 	    yyTimezone = $6;
 	    yyMeridian = MER24;
 	    yyDSTmode = DSToff;
 	}
 	;
 
 zone	: tZONE {
 	    $$ = $1;
 	    yyDSTmode = DSToff;
 	}
 	| tDAYZONE {
 	    $$ = $1;
 	    yyDSTmode = DSTon;
 	}
 	| tZONE numzone {
 	    /* Only allow "GMT+300" and "GMT-0800" */
 	    if ($1 != 0) {
 		YYABORT;
 	    }
 	    $$ = $2;
 	    yyDSTmode = DSToff;
 	}
 	| numzone {
 	    $$ = $1;
 	    yyDSTmode = DSToff;
 	}
 	;
 
 numzone	: tSNUMBER {
 	    int		i;
 
 	    /* Unix and GMT and numeric timezones -- a little confusing. */
 	    if ($1 < 0) {
 		/* Don't work with negative modulus. */
 		$1 = -$1;
 		if ($1 > 9999 || (i = $1 % 100) >= 60) {
 		    YYABORT;
 		}
 		$$ = ($1 / 100) * 60 + i;
 	    }
 	    else {
 		if ($1 > 9999 || (i = $1 % 100) >= 60) {
 		    YYABORT;
 		}
 		$$ = -(($1 / 100) * 60 + i);
 	    }
 	}
 	;
 
 date	: tUNUMBER '/' tUNUMBER {
 	    yyMonth = $1;
 	    yyDay = $3;
 	}
 	| tUNUMBER '/' tUNUMBER '/' tUNUMBER {
 	    if ($1 > 100) {
 		/* assume YYYY/MM/DD format, so need not to add 1900 */
 		if ($1 > 999) {
 		    yyYear = $1;
 		} else {
 		    yyYear = 1900 + $1;
 		}
 		yyMonth = $3;
 		yyDay = $5;
 	    }
 	    else {
 		/* assume MM/DD/YY* format */
 		yyMonth = $1;
 		yyDay = $3;
 		if ($5 > 999) {
 		    /* assume year is YYYY format, so need not to add 1900 */
 		    yyYear = $5;
 		} else if ($5 < 100) {
 		    /* assume year is YY format, so need to add 1900 */
 		    yyYear = $5 + (yyYear / 100 + (yyYear % 100 - $5) / 50) * 100;
 		} else {
 		    yyYear = 1900 + $5;
 		}
 	    }
 	}
 	| tMONTH tUNUMBER {
 	    yyMonth = $1;
 	    yyDay = $2;
 	}
 	| tMONTH tUNUMBER ',' tUNUMBER {
 	    yyMonth = $1;
 	    yyDay = $2;
 	    if ($4 > 999) {
 		/* assume year is YYYY format, so need not to add 1900 */
 		yyYear = $4;
 	    } else if ($4 < 100) {
 		/* assume year is YY format, so need to add 1900 */
 		yyYear = $4 + (yyYear / 100 + (yyYear % 100 - $4) / 50) * 100;
 	    } else {
 		yyYear = 1900 + $4;
 	    }
 	}
 	| tUNUMBER tMONTH {
 	    yyDay = $1;
 	    yyMonth = $2;
 	}
 	| tUNUMBER tMONTH tUNUMBER {
 	    yyDay = $1;
 	    yyMonth = $2;
 	    if ($3 > 999) {
 		/* assume year is YYYY format, so need not to add 1900 */
 		yyYear = $3;
 	    } else if ($3 < 100) {
 		/* assume year is YY format, so need to add 1900 */
 		yyYear = $3 + (yyYear / 100 + (yyYear % 100 - $3) / 50) * 100;
 	    } else {
 		yyYear = 1900 + $3;
 	    }
 	}
 	| tDAY ',' tUNUMBER tMONTH tUNUMBER {
 	    yyDay = $3;
 	    yyMonth = $4;
 	    if ($5 > 999) {
 		/* assume year is YYYY format, so need not to add 1900 */
 		yyYear = $5;
 	    } else if ($5 < 100) {
 		/* assume year is YY format, so need to add 1900 */
 		yyYear = $5 + (yyYear / 100 + (yyYear % 100 - $5) / 50) * 100;
 	    } else {
 		yyYear = 1900 + $5;
 	    }
 	}
 	;
 
 rel	: tSNUMBER tSEC_UNIT {
 	    yyRelSeconds += $1 * $2;
 	}
 	| tUNUMBER tSEC_UNIT {
 	    yyRelSeconds += $1 * $2;
 	}
 	| tSNUMBER tMONTH_UNIT {
 	    yyRelMonth += $1 * $2;
 	}
 	| tUNUMBER tMONTH_UNIT {
 	    yyRelMonth += $1 * $2;
 	}
 	;
 
 o_merid	: /* NULL */ {
 	    $$ = MER24;
 	}
 	| tMERIDIAN {
 	    $$ = $1;
 	}
 	;
 
 %%
 
 /* Month and day table. */
 static TABLE	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 },
     { "october",	tMONTH, 10 },
     { "november",	tMONTH, 11 },
     { "december",	tMONTH, 12 },
 	/* The value of the day isn't used... */
     { "sunday",		tDAY, 0 },
     { "monday",		tDAY, 0 },
     { "tuesday",	tDAY, 0 },
     { "wednesday",	tDAY, 0 },
     { "thursday",	tDAY, 0 },
     { "friday",		tDAY, 0 },
     { "saturday",	tDAY, 0 },
 };
 
 /* Time units table. */
 static TABLE	UnitsTable[] = {
     { "year",		tMONTH_UNIT,	12 },
     { "month",		tMONTH_UNIT,	1 },
     { "week",		tSEC_UNIT,	7 * 24 * 60 * 60 },
     { "day",		tSEC_UNIT,	1 * 24 * 60 * 60 },
     { "hour",		tSEC_UNIT,	60 * 60 },
     { "minute",		tSEC_UNIT,	60 },
     { "min",		tSEC_UNIT,	60 },
     { "second",		tSEC_UNIT,	1 },
     { "sec",		tSEC_UNIT,	1 },
 };
 
 /* Timezone table. */
 static TABLE	TimezoneTable[] = {
     { "gmt",	tZONE,     HOUR( 0) },	/* Greenwich Mean */
     { "ut",	tZONE,     HOUR( 0) },	/* Universal */
     { "utc",	tZONE,     HOUR( 0) },	/* Universal Coordinated */
     { "cut",	tZONE,     HOUR( 0) },	/* Coordinated Universal */
     { "z",	tZONE,     HOUR( 0) },	/* Greenwich Mean */
     { "wet",	tZONE,     HOUR( 0) },	/* Western European */
     { "bst",	tDAYZONE,  HOUR( 0) },	/* British Summer */
     { "nst",	tZONE,     HOUR(3)+30 }, /* Newfoundland Standard */
     { "ndt",	tDAYZONE,  HOUR(3)+30 }, /* Newfoundland Daylight */
     { "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 */
     { "akst",	tZONE,     HOUR( 9) },	/* Alaska Standard */
     { "akdt",	tDAYZONE,  HOUR( 9) },	/* Alaska Daylight */
     { "hst",	tZONE,     HOUR(10) },	/* Hawaii Standard */
     { "hast",	tZONE,     HOUR(10) },	/* Hawaii-Aleutian Standard */
     { "hadt",	tDAYZONE,  HOUR(10) },	/* Hawaii-Aleutian Daylight */
     { "ces",	tDAYZONE,  -HOUR(1) },	/* Central European Summer */
     { "cest",	tDAYZONE,  -HOUR(1) },	/* Central European Summer */
     { "mez",	tZONE,     -HOUR(1) },	/* Middle European */
     { "mezt",	tDAYZONE,  -HOUR(1) },	/* Middle European Summer */
     { "cet",	tZONE,     -HOUR(1) },	/* Central European */
     { "met",	tZONE,     -HOUR(1) },	/* Middle European */
     { "eet",	tZONE,     -HOUR(2) },	/* Eastern Europe */
     { "msk",	tZONE,     -HOUR(3) },	/* Moscow Winter */
     { "msd",	tDAYZONE,  -HOUR(3) },	/* Moscow Summer */
     { "wast",	tZONE,     -HOUR(8) },	/* West Australian Standard */
     { "wadt",	tDAYZONE,  -HOUR(8) },	/* West Australian Daylight */
     { "hkt",	tZONE,     -HOUR(8) },	/* Hong Kong */
     { "cct",	tZONE,     -HOUR(8) },	/* China Coast */
     { "jst",	tZONE,     -HOUR(9) },	/* Japan Standard */
     { "kst",	tZONE,     -HOUR(9) },	/* Korean Standard */
     { "kdt",	tZONE,     -HOUR(9) },	/* Korean Daylight */
     { "cast",	tZONE,     -(HOUR(9)+30) }, /* Central Australian Standard */
     { "cadt",	tDAYZONE,  -(HOUR(9)+30) }, /* Central Australian Daylight */
     { "east",	tZONE,     -HOUR(10) },	/* Eastern Australian Standard */
     { "eadt",	tDAYZONE,  -HOUR(10) },	/* Eastern Australian Daylight */
     { "nzst",	tZONE,     -HOUR(12) },	/* New Zealand Standard */
     { "nzdt",	tDAYZONE,  -HOUR(12) },	/* New Zealand Daylight */
 
     /* For completeness we include the following entries. */
 #if	0
 
     /* Duplicate names.  Either they conflict with a zone listed above
      * (which is either more likely to be seen or just been in circulation
      * longer), or they conflict with another zone in this section and
      * we could not reasonably choose one over the other. */
     { "fst",	tZONE,     HOUR( 2) },	/* Fernando De Noronha Standard */
     { "fdt",	tDAYZONE,  HOUR( 2) },	/* Fernando De Noronha Daylight */
     { "bst",	tZONE,     HOUR( 3) },	/* Brazil Standard */
     { "est",	tZONE,     HOUR( 3) },	/* Eastern Standard (Brazil) */
     { "edt",	tDAYZONE,  HOUR( 3) },	/* Eastern Daylight (Brazil) */
     { "wst",	tZONE,     HOUR( 4) },	/* Western Standard (Brazil) */
     { "wdt",	tDAYZONE,  HOUR( 4) },	/* Western Daylight (Brazil) */
     { "cst",	tZONE,     HOUR( 5) },	/* Chile Standard */
     { "cdt",	tDAYZONE,  HOUR( 5) },	/* Chile Daylight */
     { "ast",	tZONE,     HOUR( 5) },	/* Acre Standard */
     { "adt",	tDAYZONE,  HOUR( 5) },	/* Acre Daylight */
     { "cst",	tZONE,     HOUR( 5) },	/* Cuba Standard */
     { "cdt",	tDAYZONE,  HOUR( 5) },	/* Cuba Daylight */
     { "est",	tZONE,     HOUR( 6) },	/* Easter Island Standard */
     { "edt",	tDAYZONE,  HOUR( 6) },	/* Easter Island Daylight */
     { "sst",	tZONE,     HOUR(11) },	/* Samoa Standard */
     { "ist",	tZONE,     -HOUR(2) },	/* Israel Standard */
     { "idt",	tDAYZONE,  -HOUR(2) },	/* Israel Daylight */
     { "idt",	tDAYZONE,  -(HOUR(3)+30) }, /* Iran Daylight */
     { "ist",	tZONE,     -(HOUR(3)+30) }, /* Iran Standard */
     { "cst",	 tZONE,     -HOUR(8) },	/* China Standard */
     { "cdt",	 tDAYZONE,  -HOUR(8) },	/* China Daylight */
     { "sst",	 tZONE,     -HOUR(8) },	/* Singapore Standard */
 
     /* Dubious (e.g., not in Olson's TIMEZONE package) or obsolete. */
     { "gst",	tZONE,     HOUR( 3) },	/* Greenland Standard */
     { "wat",	tZONE,     -HOUR(1) },	/* West Africa */
     { "at",	tZONE,     HOUR( 2) },	/* Azores */
     { "gst",	tZONE,     -HOUR(10) },	/* Guam Standard */
     { "nft",	tZONE,     HOUR(3)+30 }, /* Newfoundland */
     { "idlw",	tZONE,     HOUR(12) },	/* International Date Line West */
     { "mewt",	tZONE,     -HOUR(1) },	/* Middle European Winter */
     { "mest",	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 */
     { "bt",	tZONE,     -HOUR(3) },	/* Baghdad */
     { "it",	tZONE,     -(HOUR(3)+30) }, /* Iran */
     { "zp4",	tZONE,     -HOUR(4) },	/* USSR Zone 3 */
     { "zp5",	tZONE,     -HOUR(5) },	/* USSR Zone 4 */
     { "ist",	tZONE,     -(HOUR(5)+30) }, /* Indian Standard */
     { "zp6",	tZONE,     -HOUR(6) },	/* USSR Zone 5 */
     { "nst",	tZONE,     -HOUR(7) },	/* North Sumatra */
     { "sst",	tZONE,     -HOUR(7) },	/* South Sumatra */
     { "jt",	tZONE,     -(HOUR(7)+30) }, /* Java (3pm in Cronusland!) */
     { "nzt",	tZONE,     -HOUR(12) },	/* New Zealand */
     { "idle",	tZONE,     -HOUR(12) },	/* International Date Line East */
     { "cat",	tZONE,     HOUR(10) },	/* -- expired 1967 */
     { "nt",	tZONE,     HOUR(11) },	/* -- expired 1967 */
     { "ahst",	tZONE,     HOUR(10) },	/* -- expired 1983 */
     { "hdt",	tDAYZONE,  HOUR(10) },	/* -- expired 1986 */
 #endif	/* 0 */
 };
 
 
 
 static void
 date_error(const char *s)
 {
     s = s;			/* ARGSUSED */
     /* NOTREACHED */
 }
 
 
 static time_t
 ToSeconds(time_t Hours, time_t Minutes, time_t Seconds, MERIDIAN Meridian)
 {
     if (Minutes < 0 || Minutes > 59 || Seconds < 0 || Seconds > 61)
 	return -1;
     if (Meridian == MER24) {
 	if (Hours < 0 || Hours > 23)
 	    return -1;
     }
     else {
 	if (Hours < 1 || Hours > 12)
 	    return -1;
 	if (Hours == 12)
 	    Hours = 0;
 	if (Meridian == MERpm)
 	    Hours += 12;
     }
     return (Hours * 60L + Minutes) * 60L + Seconds;
 }
 
 
 static time_t
 Convert(time_t Month, time_t Day, time_t Year, time_t Hours, time_t Minutes,
 	time_t Seconds, MERIDIAN Meridian, DSTMODE dst)
 {
     static int	DaysNormal[13] = {
 	0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
     };
     static int	DaysLeap[13] = {
 	0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
     };
     static int	LeapYears[] = {
 	1972, 1976, 1980, 1984, 1988, 1992, 1996,
 	2000, 2004, 2008, 2012, 2016, 2020, 2024, 2028, 2032, 2036
     };
     int	                *yp;
     int	                *mp;
     time_t	        Julian;
     int	                i;
     time_t		tod;
 
     /* Year should not be passed as a relative value, but absolute one.
        so this should not happen, but just ensure it */
     if (Year < 0)
 	Year = -Year;
     if (Year < 100) {
 	Year += 1900;
 	if (Year < EPOCH)
 	    Year += 100;
     }
     for (mp = DaysNormal, yp = LeapYears; yp < ARRAY_END(LeapYears); yp++)
 	if (Year == *yp) {
 	    mp = DaysLeap;
 	    break;
 	}
     if (Year < EPOCH || Year > END_OF_TIME
      || Month < 1 || Month > 12
      /* NOSTRICT *//* conversion from long may lose accuracy */
      || Day < 1 || Day > mp[(int)Month])
 	return -1;
 
     Julian = Day - 1 + (Year - EPOCH) * 365;
     for (yp = LeapYears; yp < ARRAY_END(LeapYears); yp++, Julian++)
 	if (Year <= *yp)
 	    break;
     for (i = 1; i < Month; i++)
 	Julian += *++mp;
     Julian *= SECSPERDAY;
     Julian += yyTimezone * 60L;
     if ((tod = ToSeconds(Hours, Minutes, Seconds, Meridian)) < 0)
 	return -1;
     Julian += tod;
     tod = Julian;
     if (dst == DSTon || (dst == DSTmaybe && localtime(&tod)->tm_isdst))
 	Julian -= DST_OFFSET * 60 * 60;
     return Julian;
 }
 
 
 static time_t
 DSTcorrect(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) * DST_OFFSET * 60 * 60;
 }
 
 
 static time_t
 RelativeMonth(time_t Start, time_t RelMonth)
 {
     struct tm	*tm;
     time_t	Month;
     time_t	Year;
 
     tm = localtime(&Start);
     Month = 12 * tm->tm_year + tm->tm_mon + RelMonth;
     Year = Month / 12;
     Year += 1900;
     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(char *buff, int length)
 {
     char *p;
     const char *q;
     TABLE *tp;
     int	c;
 
     p = buff;
     c = p[0];
 
     /* See if we have an abbreviation for a month. */
     if (length == 3 || (length == 4 && p[3] == '.'))
 	for (tp = MonthDayTable; tp < ARRAY_END(MonthDayTable); tp++) {
 	    q = tp->name;
 	    if (c == q[0] && p[1] == q[1] && p[2] == q[2]) {
 		yylval.Number = tp->value;
 		return tp->type;
 	    }
 	}
     else
 	for (tp = MonthDayTable; tp < ARRAY_END(MonthDayTable); tp++)
 	    if (c == tp->name[0] && strcmp(p, tp->name) == 0) {
 		yylval.Number = tp->value;
 		return tp->type;
 	    }
 
     /* Try for a timezone. */
     for (tp = TimezoneTable; tp < ARRAY_END(TimezoneTable); tp++)
 	if (c == tp->name[0] && p[1] == tp->name[1]
 	 && strcmp(p, tp->name) == 0) {
 	    yylval.Number = tp->value;
 	    return tp->type;
 	}
 
     /* Try the units table. */
     for (tp = UnitsTable; tp < ARRAY_END(UnitsTable); tp++)
 	if (c == tp->name[0] && strcmp(p, tp->name) == 0) {
 	    yylval.Number = tp->value;
 	    return tp->type;
 	}
 
     /* Strip off any plural and try the units table again. */
     if (--length > 0 && p[length] == 's') {
 	p[length] = '\0';
 	for (tp = UnitsTable; tp < ARRAY_END(UnitsTable); tp++)
 	    if (c == tp->name[0] && strcmp(p, tp->name) == 0) {
 		p[length] = 's';
 		yylval.Number = tp->value;
 		return tp->type;
 	    }
 	p[length] = 's';
     }
     length++;
 
     /* Drop out any periods. */
     for (p = buff, q = buff; *q; q++)
 	if (*q != '.')
 	    *p++ = *q;
     *p = '\0';
 
     /* Try the meridians. */
     if (buff[1] == 'm' && buff[2] == '\0') {
 	if (buff[0] == 'a') {
 	    yylval.Meridian = MERam;
 	    return tMERIDIAN;
 	}
 	if (buff[0] == 'p') {
 	    yylval.Meridian = MERpm;
 	    return tMERIDIAN;
 	}
     }
 
     /* If we saw any periods, try the timezones again. */
     if (p - buff != length) {
 	c = buff[0];
 	for (p = buff, tp = TimezoneTable; tp < ARRAY_END(TimezoneTable); tp++)
 	    if (c == tp->name[0] && p[1] == tp->name[1]
 	    && strcmp(p, tp->name) == 0) {
 		yylval.Number = tp->value;
 		return tp->type;
 	    }
     }
 
     /* Unknown word -- assume GMT timezone. */
     yylval.Number = 0;
     return tZONE;
 }
 
 
 static int
 date_lex(void)
 {
     char	        c;
     char	        *p;
     char		buff[20];
     int	                sign;
     int	                i;
     int	                nesting;
 
     for ( ; ; ) {
 	/* Get first character after the whitespace. */
 	for ( ; ; ) {
 	    while (CTYPE(isspace, (int)*yyInput))
 		yyInput++;
 	    c = *yyInput;
 
 	    /* Ignore RFC 822 comments, typically time zone names. */
 	    if (c != LPAREN)
 		break;
 	    for (nesting = 1; (c = *++yyInput) != RPAREN || --nesting; )
 		if (c == LPAREN)
 		    nesting++;
 		else if (!IS7BIT(c) || c == '\0' || c == '\r'
 		     || (c == '\\' && ((c = *++yyInput) == '\0' || !IS7BIT(c))))
 		    /* Lexical error: bad comment. */
 		    return '?';
 	    yyInput++;
 	}
 
 	/* A number? */
 	if (CTYPE(isdigit, (int)c) || c == '-' || c == '+') {
 	    if (c == '-' || c == '+') {
 		sign = c == '-' ? -1 : 1;
 		yyInput++;
 		if (!CTYPE(isdigit, (int)*yyInput))
 		    /* Skip the plus or minus sign. */
 		    continue;
 	    }
 	    else
 		sign = 0;
 	    for (i = 0; (c = *yyInput++) != '\0' && CTYPE(isdigit, (int)c); )
 		i = 10 * i + c - '0';
 	    yyInput--;
 	    yylval.Number = sign < 0 ? -i : i;
 	    return sign ? tSNUMBER : tUNUMBER;
 	}
 
 	/* A word? */
 	if (CTYPE(isalpha, (int)c)) {
 	    for (p = buff; (c = *yyInput++) == '.' || CTYPE(isalpha, (int)c); )
 		if (p < &buff[sizeof buff - 1])
 		    *p++ = CTYPE(isupper, (int)c) ? tolower(c) : c;
 	    *p = '\0';
 	    yyInput--;
 	    return LookupWord(buff, p - buff);
 	}
 
 	return *yyInput++;
     }
 }
 
 
 time_t
 parsedate(char *p)
 {
     time_t		now;
     struct tm		*tm;
     time_t		Start;
 
     now = time(NULL);
     yyInput = p;
 
     tm = gmtime(&now);
     yyYear = tm->tm_year + 1900;
     yyMonth = tm->tm_mon + 1;
     yyDay = tm->tm_mday;
     yyTimezone = 0;
     yyDSTmode = DSTmaybe;
     yyHour = 0;
     yyMinutes = 0;
     yySeconds = 0;
     yyMeridian = MER24;
     yyRelSeconds = 0;
     yyRelMonth = 0;
     yyHaveDate = 0;
     yyHaveRel = 0;
     yyHaveTime = 0;
 
     if (date_parse() || yyHaveTime > 1 || yyHaveDate > 1)
 	return -1;
 
     if (yyHaveDate || yyHaveTime) {
 	Start = Convert(yyMonth, yyDay, yyYear, yyHour, yyMinutes, yySeconds,
 		    yyMeridian, yyDSTmode);
 	if (Start < 0)
 	    return -1;
     }
     else {
 	Start = now;
 	if (!yyHaveRel)
 	    Start -= (tm->tm_hour * 60L + tm->tm_min) * 60L + tm->tm_sec;
     }
 
     Start += yyRelSeconds;
     if (yyRelMonth)
 	Start += RelativeMonth(Start, yyRelMonth);
 
     /* 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)
 
 #if	YYDEBUG
 extern int	yydebug;
 #endif	/* YYDEBUG */
 
 /* ARGSUSED */
 int
 main(int ac, char *av[])
 {
     char	buff[128];
     time_t	d;
 
 #if	YYDEBUG
     yydebug = 1;
 #endif	/* YYDEBUG */
 
     printf("Enter date, or blank line to exit.\n\t> ");
     for ( ; ; ) {
 	printf("\t> ");
 	fflush(stdout);
 	if (gets(buff) == NULL || buff[0] == '\n')
 	    break;
 #if	YYDEBUG
 	if (strcmp(buff, "yydebug") == 0) {
 	    yydebug = !yydebug;
 	    printf("yydebug = %s\n", yydebug ? "on" : "off");
 	    continue;
 	}
 #endif	/* YYDEBUG */
 	d = parsedate(buff);
 	if (d == -1)
 	    printf("Bad format - couldn't convert.\n");
 	else
 	    printf("%s", ctime(&d));
     }
 
     exit(0);
     /* NOTREACHED */
 }
 #endif	/* defined(TEST) */