citadel/parsedate.y

   1 %{
   2 /* $Revision$
   3 **
   4 **  Originally written by Steven M. Bellovin <smb@research.att.com> while
   5 **  at the University of North Carolina at Chapel Hill.  Later tweaked by
   6 **  a couple of people on Usenet.  Completely overhauled by Rich $alz
   7 **  <rsalz@osf.org> and Jim Berets <jberets@bbn.com> in August, 1990.
   8 **  Further revised (removed obsolete constructs and cleaned up timezone
   9 **  names) in August, 1991, by Rich.  Paul Eggert <eggert@twinsun.com>
  10 **  helped in September, 1992.  Art Cancro <ajc@uncensored.citadel.org> cleaned
  11 **  it up for ANSI C in December, 1999.
  12 **
  13 **  This grammar has six shift/reduce conflicts.
  14 **
  15 **  This code is in the public domain and has no copyright.
  16 */
  17 /* SUPPRESS 530 *//* Empty body for statement */
  18 /* SUPPRESS 593 on yyerrlab *//* Label was not used */
  19 /* SUPPRESS 593 on yynewstate *//* Label was not used */
  20 /* SUPPRESS 595 on yypvt *//* Automatic variable may be used before set */
  21
  22 #include "sysdep.h"
  23
  24 #include <stdio.h>
  25 #include <stdlib.h>
  26 #include <sys/types.h>
  27 #include <ctype.h>
  28
  29 #if TIME_WITH_SYS_TIME
  30 # include <sys/time.h>
  31 # include <time.h>
  32 #else
  33 # if HAVE_SYS_TIME_H
  34 #  include <sys/time.h>
  35 # else
  36 #  include <time.h>
  37 # endif
  38 #endif
  39
  40 #if HAVE_STRING_H
  41 # if !STDC_HEADERS && HAVE_MEMORY_H
  42 #  include <memory.h>
  43 # endif
  44 # include <string.h>
  45 #endif
  46 #if HAVE_STRINGS_H
  47 # include <strings.h>
  48 #endif
  49
  50 #include "parsedate.h"
  51
  52 int date_lex(void);
  53
  54 #define yyparse         date_parse
  55 #define yylex           date_lex
  56 #define yyerror         date_error
  57
  58
  59     /* See the LeapYears table in Convert. */
  60 #define EPOCH           1970
  61 #define END_OF_TIME     2038
  62     /* Constants for general time calculations. */
  63 #define DST_OFFSET      1
  64 #define SECSPERDAY      (24L * 60L * 60L)
  65     /* Readability for TABLE stuff. */
  66 #define HOUR(x)         (x * 60)
  67
  68 #define LPAREN          '('
  69 #define RPAREN          ')'
  70 #define IS7BIT(x)       ((unsigned int)(x) < 0200)
  71
  72 #define SIZEOF(array)   ((int)(sizeof array / sizeof array[0]))
  73 #define ENDOF(array)    (&array[SIZEOF(array)])
  74
  75
  76 /*
  77 **  An entry in the lexical lookup table.
  78 */
  79 typedef struct _TABLE {
  80     char        *name;
  81     int         type;
  82     time_t      value;
  83 } TABLE;
  84
  85 /*
  86 **  Daylight-savings mode:  on, off, or not yet known.
  87 */
  88 typedef enum _DSTMODE {
  89     DSTon, DSToff, DSTmaybe
  90 } DSTMODE;
  91
  92 /*
  93 **  Meridian:  am, pm, or 24-hour style.
  94 */
  95 typedef enum _MERIDIAN {
  96     MERam, MERpm, MER24
  97 } MERIDIAN;
  98
  99
 100 /*
 101 **  Global variables.  We could get rid of most of them by using a yacc
 102 **  union, but this is more efficient.  (This routine predates the
 103 **  yacc %union construct.)
 104 */
 105 static char     *yyInput;
 106 static DSTMODE  yyDSTmode;
 107 static int      yyHaveDate;
 108 static int      yyHaveRel;
 109 static int      yyHaveTime;
 110 static time_t   yyTimezone;
 111 static time_t   yyDay;
 112 static time_t   yyHour;
 113 static time_t   yyMinutes;
 114 static time_t   yyMonth;
 115 static time_t   yySeconds;
 116 static time_t   yyYear;
 117 static MERIDIAN yyMeridian;
 118 static time_t   yyRelMonth;
 119 static time_t   yyRelSeconds;
 120
 121
 122 static void             date_error(char *);
 123 %}
 124
 125 %union {
 126     time_t              Number;
 127     enum _MERIDIAN      Meridian;
 128 }
 129
 130 %token  tDAY tDAYZONE tMERIDIAN tMONTH tMONTH_UNIT tSEC_UNIT tSNUMBER
 131 %token  tUNUMBER tZONE
 132
 133 %type   <Number>        tDAYZONE tMONTH tMONTH_UNIT tSEC_UNIT
 134 %type   <Number>        tSNUMBER tUNUMBER tZONE numzone zone
 135 %type   <Meridian>      tMERIDIAN o_merid
 136
 137 %%
 138
 139 spec    : /* NULL */
 140         | spec item
 141         ;
 142
 143 item    : time {
 144             yyHaveTime++;
 145 #ifdef lint
 146             /* I am compulsive about lint natterings... */
 147             if (yyHaveTime == -1) {
 148                 YYERROR;
 149             }
 150 #endif /* lint */
 151         }
 152         | time zone {
 153             yyHaveTime++;
 154             yyTimezone = $2;
 155         }
 156         | date {
 157             yyHaveDate++;
 158         }
 159         | rel {
 160             yyHaveRel = 1;
 161         }
 162         ;
 163
 164 time    : tUNUMBER o_merid {
 165             if ($1 < 100) {
 166                 yyHour = $1;
 167                 yyMinutes = 0;
 168             }
 169             else {
 170                 yyHour = $1 / 100;
 171                 yyMinutes = $1 % 100;
 172             }
 173             yySeconds = 0;
 174             yyMeridian = $2;
 175         }
 176         | tUNUMBER ':' tUNUMBER o_merid {
 177             yyHour = $1;
 178             yyMinutes = $3;
 179             yySeconds = 0;
 180             yyMeridian = $4;
 181         }
 182         | tUNUMBER ':' tUNUMBER numzone {
 183             yyHour = $1;
 184             yyMinutes = $3;
 185             yyTimezone = $4;
 186             yyMeridian = MER24;
 187             yyDSTmode = DSToff;
 188         }
 189         | tUNUMBER ':' tUNUMBER ':' tUNUMBER o_merid {
 190             yyHour = $1;
 191             yyMinutes = $3;
 192             yySeconds = $5;
 193             yyMeridian = $6;
 194         }
 195         | tUNUMBER ':' tUNUMBER ':' tUNUMBER numzone {
 196             yyHour = $1;
 197             yyMinutes = $3;
 198             yySeconds = $5;
 199             yyTimezone = $6;
 200             yyMeridian = MER24;
 201             yyDSTmode = DSToff;
 202         }
 203         ;
 204
 205 zone    : tZONE {
 206             $$ = $1;
 207             yyDSTmode = DSToff;
 208         }
 209         | tDAYZONE {
 210             $$ = $1;
 211             yyDSTmode = DSTon;
 212         }
 213         | tZONE numzone {
 214             /* Only allow "GMT+300" and "GMT-0800" */
 215             if ($1 != 0) {
 216                 YYABORT;
 217             }
 218             $$ = $2;
 219             yyDSTmode = DSToff;
 220         }
 221         | numzone {
 222             $$ = $1;
 223             yyDSTmode = DSToff;
 224         }
 225         ;
 226
 227 numzone : tSNUMBER {
 228             int         i;
 229
 230             /* Unix and GMT and numeric timezones -- a little confusing. */
 231             if ($1 < 0) {
 232                 /* Don't work with negative modulus. */
 233                 $1 = -$1;
 234                 if ($1 > 9999 || (i = $1 % 100) >= 60) {
 235                     YYABORT;
 236                 }
 237                 $$ = ($1 / 100) * 60 + i;
 238             }
 239             else {
 240                 if ($1 > 9999 || (i = $1 % 100) >= 60) {
 241                     YYABORT;
 242                 }
 243                 $$ = -(($1 / 100) * 60 + i);
 244             }
 245         }
 246         ;
 247
 248 date    : tUNUMBER '/' tUNUMBER {
 249             yyMonth = $1;
 250             yyDay = $3;
 251         }
 252         | tUNUMBER '/' tUNUMBER '/' tUNUMBER {
 253             if ($1 > 100) {
 254                 yyYear = $1;
 255                 yyMonth = $3;
 256                 yyDay = $5;
 257             }
 258             else {
 259                 yyMonth = $1;
 260                 yyDay = $3;
 261                 yyYear = $5;
 262             }
 263         }
 264         | tMONTH tUNUMBER {
 265             yyMonth = $1;
 266             yyDay = $2;
 267         }
 268         | tMONTH tUNUMBER ',' tUNUMBER {
 269             yyMonth = $1;
 270             yyDay = $2;
 271             yyYear = $4;
 272         }
 273         | tUNUMBER tMONTH {
 274             yyDay = $1;
 275             yyMonth = $2;
 276         }
 277         | tUNUMBER tMONTH tUNUMBER {
 278             yyDay = $1;
 279             yyMonth = $2;
 280             yyYear = $3;
 281         }
 282         | tDAY ',' tUNUMBER tMONTH tUNUMBER {
 283             yyDay = $3;
 284             yyMonth = $4;
 285             yyYear = $5;
 286         }
 287         ;
 288
 289 rel     : tSNUMBER tSEC_UNIT {
 290             yyRelSeconds += $1 * $2;
 291         }
 292         | tUNUMBER tSEC_UNIT {
 293             yyRelSeconds += $1 * $2;
 294         }
 295         | tSNUMBER tMONTH_UNIT {
 296             yyRelMonth += $1 * $2;
 297         }
 298         | tUNUMBER tMONTH_UNIT {
 299             yyRelMonth += $1 * $2;
 300         }
 301         ;
 302
 303 o_merid : /* NULL */ {
 304             $$ = MER24;
 305         }
 306         | tMERIDIAN {
 307             $$ = $1;
 308         }
 309         ;
 310
 311 %%
 312
 313 /* Month and day table. */
 314 static TABLE    MonthDayTable[] = {
 315     { "january",        tMONTH,  1 },
 316     { "february",       tMONTH,  2 },
 317     { "march",          tMONTH,  3 },
 318     { "april",          tMONTH,  4 },
 319     { "may",            tMONTH,  5 },
 320     { "june",           tMONTH,  6 },
 321     { "july",           tMONTH,  7 },
 322     { "august",         tMONTH,  8 },
 323     { "september",      tMONTH,  9 },
 324     { "october",        tMONTH, 10 },
 325     { "november",       tMONTH, 11 },
 326     { "december",       tMONTH, 12 },
 327         /* The value of the day isn't used... */
 328     { "sunday",         tDAY, 0 },
 329     { "monday",         tDAY, 0 },
 330     { "tuesday",        tDAY, 0 },
 331     { "wednesday",      tDAY, 0 },
 332     { "thursday",       tDAY, 0 },
 333     { "friday",         tDAY, 0 },
 334     { "saturday",       tDAY, 0 },
 335 };
 336
 337 /* Time units table. */
 338 static TABLE    UnitsTable[] = {
 339     { "year",           tMONTH_UNIT,    12 },
 340     { "month",          tMONTH_UNIT,    1 },
 341     { "week",           tSEC_UNIT,      7L * 24 * 60 * 60 },
 342     { "day",            tSEC_UNIT,      1L * 24 * 60 * 60 },
 343     { "hour",           tSEC_UNIT,      60 * 60 },
 344     { "minute",         tSEC_UNIT,      60 },
 345     { "min",            tSEC_UNIT,      60 },
 346     { "second",         tSEC_UNIT,      1 },
 347     { "sec",            tSEC_UNIT,      1 },
 348 };
 349
 350 /* Timezone table. */
 351 static TABLE    TimezoneTable[] = {
 352     { "gmt",    tZONE,     HOUR( 0) },  /* Greenwich Mean */
 353     { "ut",     tZONE,     HOUR( 0) },  /* Universal */
 354     { "utc",    tZONE,     HOUR( 0) },  /* Universal Coordinated */
 355     { "cut",    tZONE,     HOUR( 0) },  /* Coordinated Universal */
 356     { "z",      tZONE,     HOUR( 0) },  /* Greenwich Mean */
 357     { "wet",    tZONE,     HOUR( 0) },  /* Western European */
 358     { "bst",    tDAYZONE,  HOUR( 0) },  /* British Summer */
 359     { "nst",    tZONE,     HOUR(3)+30 }, /* Newfoundland Standard */
 360     { "ndt",    tDAYZONE,  HOUR(3)+30 }, /* Newfoundland Daylight */
 361     { "ast",    tZONE,     HOUR( 4) },  /* Atlantic Standard */
 362     { "adt",    tDAYZONE,  HOUR( 4) },  /* Atlantic Daylight */
 363     { "est",    tZONE,     HOUR( 5) },  /* Eastern Standard */
 364     { "edt",    tDAYZONE,  HOUR( 5) },  /* Eastern Daylight */
 365     { "cst",    tZONE,     HOUR( 6) },  /* Central Standard */
 366     { "cdt",    tDAYZONE,  HOUR( 6) },  /* Central Daylight */
 367     { "mst",    tZONE,     HOUR( 7) },  /* Mountain Standard */
 368     { "mdt",    tDAYZONE,  HOUR( 7) },  /* Mountain Daylight */
 369     { "pst",    tZONE,     HOUR( 8) },  /* Pacific Standard */
 370     { "pdt",    tDAYZONE,  HOUR( 8) },  /* Pacific Daylight */
 371     { "yst",    tZONE,     HOUR( 9) },  /* Yukon Standard */
 372     { "ydt",    tDAYZONE,  HOUR( 9) },  /* Yukon Daylight */
 373     { "akst",   tZONE,     HOUR( 9) },  /* Alaska Standard */
 374     { "akdt",   tDAYZONE,  HOUR( 9) },  /* Alaska Daylight */
 375     { "hst",    tZONE,     HOUR(10) },  /* Hawaii Standard */
 376     { "hast",   tZONE,     HOUR(10) },  /* Hawaii-Aleutian Standard */
 377     { "hadt",   tDAYZONE,  HOUR(10) },  /* Hawaii-Aleutian Daylight */
 378     { "ces",    tDAYZONE,  -HOUR(1) },  /* Central European Summer */
 379     { "cest",   tDAYZONE,  -HOUR(1) },  /* Central European Summer */
 380     { "mez",    tZONE,     -HOUR(1) },  /* Middle European */
 381     { "mezt",   tDAYZONE,  -HOUR(1) },  /* Middle European Summer */
 382     { "cet",    tZONE,     -HOUR(1) },  /* Central European */
 383     { "met",    tZONE,     -HOUR(1) },  /* Middle European */
 384     { "eet",    tZONE,     -HOUR(2) },  /* Eastern Europe */
 385     { "msk",    tZONE,     -HOUR(3) },  /* Moscow Winter */
 386     { "msd",    tDAYZONE,  -HOUR(3) },  /* Moscow Summer */
 387     { "wast",   tZONE,     -HOUR(8) },  /* West Australian Standard */
 388     { "wadt",   tDAYZONE,  -HOUR(8) },  /* West Australian Daylight */
 389     { "hkt",    tZONE,     -HOUR(8) },  /* Hong Kong */
 390     { "cct",    tZONE,     -HOUR(8) },  /* China Coast */
 391     { "jst",    tZONE,     -HOUR(9) },  /* Japan Standard */
 392     { "kst",    tZONE,     -HOUR(9) },  /* Korean Standard */
 393     { "kdt",    tZONE,     -HOUR(9) },  /* Korean Daylight */
 394     { "cast",   tZONE,     -(HOUR(9)+30) }, /* Central Australian Standard */
 395     { "cadt",   tDAYZONE,  -(HOUR(9)+30) }, /* Central Australian Daylight */
 396     { "east",   tZONE,     -HOUR(10) }, /* Eastern Australian Standard */
 397     { "eadt",   tDAYZONE,  -HOUR(10) }, /* Eastern Australian Daylight */
 398     { "nzst",   tZONE,     -HOUR(12) }, /* New Zealand Standard */
 399     { "nzdt",   tDAYZONE,  -HOUR(12) }, /* New Zealand Daylight */
 400
 401     /* For completeness we include the following entries. */
 402 #if 0
 403
 404     /* Duplicate names.  Either they conflict with a zone listed above
 405      * (which is either more likely to be seen or just been in circulation
 406      * longer), or they conflict with another zone in this section and
 407      * we could not reasonably choose one over the other. */
 408     { "fst",    tZONE,     HOUR( 2) },  /* Fernando De Noronha Standard */
 409     { "fdt",    tDAYZONE,  HOUR( 2) },  /* Fernando De Noronha Daylight */
 410     { "bst",    tZONE,     HOUR( 3) },  /* Brazil Standard */
 411     { "est",    tZONE,     HOUR( 3) },  /* Eastern Standard (Brazil) */
 412     { "edt",    tDAYZONE,  HOUR( 3) },  /* Eastern Daylight (Brazil) */
 413     { "wst",    tZONE,     HOUR( 4) },  /* Western Standard (Brazil) */
 414     { "wdt",    tDAYZONE,  HOUR( 4) },  /* Western Daylight (Brazil) */
 415     { "cst",    tZONE,     HOUR( 5) },  /* Chile Standard */
 416     { "cdt",    tDAYZONE,  HOUR( 5) },  /* Chile Daylight */
 417     { "ast",    tZONE,     HOUR( 5) },  /* Acre Standard */
 418     { "adt",    tDAYZONE,  HOUR( 5) },  /* Acre Daylight */
 419     { "cst",    tZONE,     HOUR( 5) },  /* Cuba Standard */
 420     { "cdt",    tDAYZONE,  HOUR( 5) },  /* Cuba Daylight */
 421     { "est",    tZONE,     HOUR( 6) },  /* Easter Island Standard */
 422     { "edt",    tDAYZONE,  HOUR( 6) },  /* Easter Island Daylight */
 423     { "sst",    tZONE,     HOUR(11) },  /* Samoa Standard */
 424     { "ist",    tZONE,     -HOUR(2) },  /* Israel Standard */
 425     { "idt",    tDAYZONE,  -HOUR(2) },  /* Israel Daylight */
 426     { "idt",    tDAYZONE,  -(HOUR(3)+30) }, /* Iran Daylight */
 427     { "ist",    tZONE,     -(HOUR(3)+30) }, /* Iran Standard */
 428     { "cst",     tZONE,     -HOUR(8) }, /* China Standard */
 429     { "cdt",     tDAYZONE,  -HOUR(8) }, /* China Daylight */
 430     { "sst",     tZONE,     -HOUR(8) }, /* Singapore Standard */
 431
 432     /* Dubious (e.g., not in Olson's TIMEZONE package) or obsolete. */
 433     { "gst",    tZONE,     HOUR( 3) },  /* Greenland Standard */
 434     { "wat",    tZONE,     -HOUR(1) },  /* West Africa */
 435     { "at",     tZONE,     HOUR( 2) },  /* Azores */
 436     { "gst",    tZONE,     -HOUR(10) }, /* Guam Standard */
 437     { "nft",    tZONE,     HOUR(3)+30 }, /* Newfoundland */
 438     { "idlw",   tZONE,     HOUR(12) },  /* International Date Line West */
 439     { "mewt",   tZONE,     -HOUR(1) },  /* Middle European Winter */
 440     { "mest",   tDAYZONE,  -HOUR(1) },  /* Middle European Summer */
 441     { "swt",    tZONE,     -HOUR(1) },  /* Swedish Winter */
 442     { "sst",    tDAYZONE,  -HOUR(1) },  /* Swedish Summer */
 443     { "fwt",    tZONE,     -HOUR(1) },  /* French Winter */
 444     { "fst",    tDAYZONE,  -HOUR(1) },  /* French Summer */
 445     { "bt",     tZONE,     -HOUR(3) },  /* Baghdad */
 446     { "it",     tZONE,     -(HOUR(3)+30) }, /* Iran */
 447     { "zp4",    tZONE,     -HOUR(4) },  /* USSR Zone 3 */
 448     { "zp5",    tZONE,     -HOUR(5) },  /* USSR Zone 4 */
 449     { "ist",    tZONE,     -(HOUR(5)+30) }, /* Indian Standard */
 450     { "zp6",    tZONE,     -HOUR(6) },  /* USSR Zone 5 */
 451     { "nst",    tZONE,     -HOUR(7) },  /* North Sumatra */
 452     { "sst",    tZONE,     -HOUR(7) },  /* South Sumatra */
 453     { "jt",     tZONE,     -(HOUR(7)+30) }, /* Java (3pm in Cronusland!) */
 454     { "nzt",    tZONE,     -HOUR(12) }, /* New Zealand */
 455     { "idle",   tZONE,     -HOUR(12) }, /* International Date Line East */
 456     { "cat",    tZONE,     HOUR(10) },  /* -- expired 1967 */
 457     { "nt",     tZONE,     HOUR(11) },  /* -- expired 1967 */
 458     { "ahst",   tZONE,     HOUR(10) },  /* -- expired 1983 */
 459     { "hdt",    tDAYZONE,  HOUR(10) },  /* -- expired 1986 */
 460 #endif /* 0 */
 461 };
 462
 463
 464 /* ARGSUSED */
 465 static void
 466 date_error(char *s)
 467 {
 468     /* NOTREACHED */
 469 }
 470
 471
 472 static time_t
 473 ToSeconds(time_t Hours, time_t Minutes, time_t Seconds, MERIDIAN Meridian)
 474 {
 475     if (Minutes < 0 || Minutes > 59 || Seconds < 0 || Seconds > 61)
 476         return -1;
 477     if (Meridian == MER24) {
 478         if (Hours < 0 || Hours > 23)
 479             return -1;
 480     }
 481     else {
 482         if (Hours < 1 || Hours > 12)
 483             return -1;
 484         if (Hours == 12)
 485             Hours = 0;
 486         if (Meridian == MERpm)
 487             Hours += 12;
 488     }
 489     return (Hours * 60L + Minutes) * 60L + Seconds;
 490 }
 491
 492
 493 static time_t
 494 Convert(time_t Month, time_t Day, time_t Year,
 495         time_t Hours, time_t Minutes, time_t Seconds,
 496         MERIDIAN Meridian, DSTMODE dst)
 497 {
 498     static int  DaysNormal[13] = {
 499         0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
 500     };
 501     static int  DaysLeap[13] = {
 502         0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
 503     };
 504     static int  LeapYears[] = {
 505         1972, 1976, 1980, 1984, 1988, 1992, 1996,
 506         2000, 2004, 2008, 2012, 2016, 2020, 2024, 2028, 2032, 2036
 507     };
 508     register int        *yp;
 509     register int        *mp;
 510     register time_t     Julian;
 511     register int        i;
 512     time_t              tod;
 513
 514     if (Year < 0)
 515         Year = -Year;
 516     if (Year < 100)
 517         Year += 1900;
 518     if (Year < EPOCH)
 519         Year += 100;
 520     for (mp = DaysNormal, yp = LeapYears; yp < ENDOF(LeapYears); yp++)
 521         if (Year == *yp) {
 522             mp = DaysLeap;
 523             break;
 524         }
 525     if (Year < EPOCH || Year > END_OF_TIME
 526      || Month < 1 || Month > 12
 527      /* NOSTRICT *//* conversion from long may lose accuracy */
 528      || Day < 1 || Day > mp[(int)Month])
 529         return -1;
 530
 531     Julian = Day - 1 + (Year - EPOCH) * 365;
 532     for (yp = LeapYears; yp < ENDOF(LeapYears); yp++, Julian++)
 533         if (Year <= *yp)
 534             break;
 535     for (i = 1; i < Month; i++)
 536         Julian += *++mp;
 537     Julian *= SECSPERDAY;
 538     Julian += yyTimezone * 60L;
 539     if ((tod = ToSeconds(Hours, Minutes, Seconds, Meridian)) < 0)
 540         return -1;
 541     Julian += tod;
 542     tod = Julian;
 543     if (dst == DSTon || (dst == DSTmaybe && localtime(&tod)->tm_isdst))
 544         Julian -= DST_OFFSET * 60L * 60L;
 545     return Julian;
 546 }
 547
 548
 549 static time_t
 550 DSTcorrect(time_t Start, time_t Future)
 551 {
 552     time_t      StartDay;
 553     time_t      FutureDay;
 554
 555     StartDay = (localtime(&Start)->tm_hour + 1) % 24;
 556     FutureDay = (localtime(&Future)->tm_hour + 1) % 24;
 557     return (Future - Start) + (StartDay - FutureDay) * DST_OFFSET * 60L * 60L;
 558 }
 559
 560
 561 static time_t
 562 RelativeMonth(time_t Start, time_t RelMonth)
 563 {
 564     struct tm   *tm;
 565     time_t      Month;
 566     time_t      Year;
 567
 568     tm = localtime(&Start);
 569     Month = 12 * tm->tm_year + tm->tm_mon + RelMonth;
 570     Year = Month / 12;
 571     Month = Month % 12 + 1;
 572     return DSTcorrect(Start,
 573             Convert(Month, (time_t)tm->tm_mday, Year,
 574                 (time_t)tm->tm_hour, (time_t)tm->tm_min, (time_t)tm->tm_sec,
 575                 MER24, DSTmaybe));
 576 }
 577
 578
 579 static int
 580 LookupWord(char *buff, register int length)
 581 {
 582     register char       *p;
 583     register char       *q;
 584     register TABLE      *tp;
 585     register int        c;
 586
 587     p = buff;
 588     c = p[0];
 589
 590     /* See if we have an abbreviation for a month. */
 591     if (length == 3 || (length == 4 && p[3] == '.'))
 592         for (tp = MonthDayTable; tp < ENDOF(MonthDayTable); tp++) {
 593             q = tp->name;
 594             if (c == q[0] && p[1] == q[1] && p[2] == q[2]) {
 595                 yylval.Number = tp->value;
 596                 return tp->type;
 597             }
 598         }
 599     else
 600         for (tp = MonthDayTable; tp < ENDOF(MonthDayTable); tp++)
 601             if (c == tp->name[0] && strcmp(p, tp->name) == 0) {
 602                 yylval.Number = tp->value;
 603                 return tp->type;
 604             }
 605
 606     /* Try for a timezone. */
 607     for (tp = TimezoneTable; tp < ENDOF(TimezoneTable); tp++)
 608         if (c == tp->name[0] && p[1] == tp->name[1]
 609          && strcmp(p, tp->name) == 0) {
 610             yylval.Number = tp->value;
 611             return tp->type;
 612         }
 613
 614     /* Try the units table. */
 615     for (tp = UnitsTable; tp < ENDOF(UnitsTable); tp++)
 616         if (c == tp->name[0] && strcmp(p, tp->name) == 0) {
 617             yylval.Number = tp->value;
 618             return tp->type;
 619         }
 620
 621     /* Strip off any plural and try the units table again. */
 622     if (--length > 0 && p[length] == 's') {
 623         p[length] = '\0';
 624         for (tp = UnitsTable; tp < ENDOF(UnitsTable); tp++)
 625             if (c == tp->name[0] && strcmp(p, tp->name) == 0) {
 626                 p[length] = 's';
 627                 yylval.Number = tp->value;
 628                 return tp->type;
 629             }
 630         p[length] = 's';
 631     }
 632     length++;
 633
 634     /* Drop out any periods. */
 635     for (p = buff, q = (char*)buff; *q; q++)
 636         if (*q != '.')
 637             *p++ = *q;
 638     *p = '\0';
 639
 640     /* Try the meridians. */
 641     if (buff[1] == 'm' && buff[2] == '\0') {
 642         if (buff[0] == 'a') {
 643             yylval.Meridian = MERam;
 644             return tMERIDIAN;
 645         }
 646         if (buff[0] == 'p') {
 647             yylval.Meridian = MERpm;
 648             return tMERIDIAN;
 649         }
 650     }
 651
 652     /* If we saw any periods, try the timezones again. */
 653     if (p - buff != length) {
 654         c = buff[0];
 655         for (p = buff, tp = TimezoneTable; tp < ENDOF(TimezoneTable); tp++)
 656             if (c == tp->name[0] && p[1] == tp->name[1]
 657             && strcmp(p, tp->name) == 0) {
 658                 yylval.Number = tp->value;
 659                 return tp->type;
 660             }
 661     }
 662
 663     /* Unknown word -- assume GMT timezone. */
 664     yylval.Number = 0;
 665     return tZONE;
 666 }
 667
 668
 669 int
 670 date_lex(void)
 671 {
 672     register char       c;
 673     register char       *p;
 674     char                buff[20];
 675     register int        sign;
 676     register int        i;
 677     register int        nesting;
 678
 679     for ( ; ; ) {
 680         /* Get first character after the whitespace. */
 681         for ( ; ; ) {
 682             while (isspace(*yyInput))
 683                 yyInput++;
 684             c = *yyInput;
 685
 686             /* Ignore RFC 822 comments, typically time zone names. */
 687             if (c != LPAREN)
 688                 break;
 689             for (nesting = 1; (c = *++yyInput) != RPAREN || --nesting; )
 690                 if (c == LPAREN)
 691                     nesting++;
 692                 else if (!IS7BIT(c) || c == '\0' || c == '\r'
 693                      || (c == '\\' && ((c = *++yyInput) == '\0' || !IS7BIT(c))))
 694                     /* Lexical error: bad comment. */
 695                     return '?';
 696             yyInput++;
 697         }
 698
 699         /* A number? */
 700         if (isdigit(c) || c == '-' || c == '+') {
 701             if (c == '-' || c == '+') {
 702                 sign = c == '-' ? -1 : 1;
 703                 yyInput++;
 704                 if (!isdigit(*yyInput))
 705                     /* Skip the plus or minus sign. */
 706                     continue;
 707             }
 708             else
 709                 sign = 0;
 710             for (i = 0; (c = *yyInput++) != '\0' && isdigit(c); )
 711                 i = 10 * i + c - '0';
 712             yyInput--;
 713             yylval.Number = sign < 0 ? -i : i;
 714             return sign ? tSNUMBER : tUNUMBER;
 715         }
 716
 717         /* A word? */
 718         if (isalpha(c)) {
 719             for (p = buff; (c = *yyInput++) == '.' || isalpha(c); )
 720                 if (p < &buff[sizeof buff - 1])
 721                     *p++ = isupper(c) ? tolower(c) : c;
 722             *p = '\0';
 723             yyInput--;
 724             return LookupWord(buff, p - buff);
 725         }
 726
 727         return *yyInput++;
 728     }
 729 }
 730
 731
 732 time_t
 733 parsedate(char *p)
 734 {
 735     extern int          date_parse(void);
 736     time_t              Start;
 737
 738     yyInput = p;
 739
 740     yyYear = 0;
 741     yyMonth = 0;
 742     yyDay = 0;
 743     yyTimezone = 0;
 744     yyDSTmode = DSTmaybe;
 745     yyHour = 0;
 746     yyMinutes = 0;
 747     yySeconds = 0;
 748     yyMeridian = MER24;
 749     yyRelSeconds = 0;
 750     yyRelMonth = 0;
 751     yyHaveDate = 0;
 752     yyHaveRel = 0;
 753     yyHaveTime = 0;
 754
 755     if (date_parse() || yyHaveTime > 1 || yyHaveDate > 1)
 756         return -1;
 757
 758     if (yyHaveDate || yyHaveTime) {
 759         Start = Convert(yyMonth, yyDay, yyYear, yyHour, yyMinutes, yySeconds,
 760                     yyMeridian, yyDSTmode);
 761         if (Start < 0)
 762             return -1;
 763     }
 764     else
 765         return -1;
 766
 767     Start += yyRelSeconds;
 768     if (yyRelMonth)
 769         Start += RelativeMonth(Start, yyRelMonth);
 770
 771     /* Have to do *something* with a legitimate -1 so it's distinguishable
 772      * from the error return value.  (Alternately could set errno on error.) */
 773     return Start == -1 ? 0 : Start;
 774 }
 775
 776
 777 #ifdef TEST
 778
 779 #if YYDEBUG
 780 extern int      yydebug;
 781 #endif /* YYDEBUG */
 782
 783 /* ARGSUSED */
 784 int
 785 main(int ac, char *av[])
 786 {
 787     char        buff[128];
 788     time_t      d;
 789
 790 #if YYDEBUG
 791     yydebug = 1;
 792 #endif /* YYDEBUG */
 793
 794     (void)printf("Enter date, or blank line to exit.\n\t> ");
 795     for ( ; ; ) {
 796         (void)printf("\t> ");
 797         (void)fflush(stdout);
 798         if (fgets(buff, sizeof buff, stdin) == NULL || buff[0] == '\n')
 799             break;
 800 #if YYDEBUG
 801         if (strcmp(buff, "yydebug") == 0) {
 802             yydebug = !yydebug;
 803             printf("yydebug = %s\n", yydebug ? "on" : "off");
 804             continue;
 805         }
 806 #endif /* YYDEBUG */
 807         d = parsedate(buff, (TIMEINFO *)NULL);
 808         if (d == -1)
 809             (void)printf("Bad format - couldn't convert.\n");
 810         else
 811             (void)printf("%s", ctime(&d));
 812     }
 813
 814     exit(0);
 815     /* NOTREACHED */
 816 }
 817 #endif /* TEST */