contrib/libarchive-2.1/tar/getdate.y

   1 %{
   2 /*
   3  * March 2005: Further modified and simplified by Tim Kientzle:
   4  * Eliminate minutes-based calculations (just do everything in
   5  * seconds), have lexer only recognize unsigned integers (handle '+'
   6  * and '-' characters in grammar), combine tables into one table with
   7  * explicit abbreviation notes, do am/pm adjustments in the grammar
   8  * (eliminate some state variables and post-processing).  Among other
   9  * things, these changes eliminated two shift/reduce conflicts.  (Went
  10  * from 10 to 8.)
  11  * All of Tim Kientzle's changes to this file are public domain.
  12  */
  13
  14 /*
  15 **  Originally written by Steven M. Bellovin <smb@research.att.com> while
  16 **  at the University of North Carolina at Chapel Hill.  Later tweaked by
  17 **  a couple of people on Usenet.  Completely overhauled by Rich $alz
  18 **  <rsalz@bbn.com> and Jim Berets <jberets@bbn.com> in August, 1990;
  19 **
  20 **  This grammar has 10 shift/reduce conflicts.
  21 **
  22 **  This code is in the public domain and has no copyright.
  23 */
  24 /* SUPPRESS 287 on yaccpar_sccsid *//* Unused static variable */
  25 /* SUPPRESS 288 on yyerrlab *//* Label unused */
  26
  27 #ifdef __FreeBSD__
  28 #include <sys/cdefs.h>
  29 __FBSDID("$FreeBSD: src/usr.bin/tar/getdate.y,v 1.8 2007/03/11 10:36:42 kientzle Exp $");
  30 #endif
  31
  32 #include <ctype.h>
  33 #include <stdio.h>
  34 #include <stdlib.h>
  35 #include <string.h>
  36 #include <time.h>
  37
  38 #define yyparse getdate_yyparse
  39 #define yylex getdate_yylex
  40 #define yyerror getdate_yyerror
  41
  42 static int yyparse(void);
  43 static int yylex(void);
  44 static int yyerror(const char *);
  45
  46 time_t get_date(char *);
  47
  48 #define EPOCH           1970
  49 #define HOUR(x)         ((time_t)(x) * 60)
  50 #define SECSPERDAY      (24L * 60L * 60L)
  51
  52 /*
  53 **  Daylight-savings mode:  on, off, or not yet known.
  54 */
  55 typedef enum _DSTMODE {
  56     DSTon, DSToff, DSTmaybe
  57 } DSTMODE;
  58
  59 /*
  60 **  Meridian:  am or pm.
  61 */
  62 enum { tAM, tPM };
  63
  64 /*
  65 **  Global variables.  We could get rid of most of these by using a good
  66 **  union as the yacc stack.  (This routine was originally written before
  67 **  yacc had the %union construct.)  Maybe someday; right now we only use
  68 **  the %union very rarely.
  69 */
  70 static char     *yyInput;
  71
  72 static DSTMODE  yyDSTmode;
  73 static time_t   yyDayOrdinal;
  74 static time_t   yyDayNumber;
  75 static int      yyHaveDate;
  76 static int      yyHaveDay;
  77 static int      yyHaveRel;
  78 static int      yyHaveTime;
  79 static int      yyHaveZone;
  80 static time_t   yyTimezone;
  81 static time_t   yyDay;
  82 static time_t   yyHour;
  83 static time_t   yyMinutes;
  84 static time_t   yyMonth;
  85 static time_t   yySeconds;
  86 static time_t   yyYear;
  87 static time_t   yyRelMonth;
  88 static time_t   yyRelSeconds;
  89
  90 %}
  91
  92 %union {
  93     time_t              Number;
  94 }
  95
  96 %token  tAGO tDAY tDAYZONE tAMPM tMONTH tMONTH_UNIT tSEC_UNIT tUNUMBER
  97 %token  tZONE tDST
  98
  99 %type   <Number>        tDAY tDAYZONE tMONTH tMONTH_UNIT
 100 %type   <Number>        tSEC_UNIT tUNUMBER tZONE tAMPM
 101
 102 %%
 103
 104 spec    : /* NULL */
 105         | spec item
 106         ;
 107
 108 item    : time { yyHaveTime++; }
 109         | zone { yyHaveZone++; }
 110         | date { yyHaveDate++; }
 111         | day { yyHaveDay++; }
 112         | rel { yyHaveRel++; }
 113         | number
 114         ;
 115
 116 time    : tUNUMBER tAMPM {
 117                 /* "7am" */
 118                 yyHour = $1;
 119                 if (yyHour == 12)
 120                         yyHour = 0;
 121                 yyMinutes = 0;
 122                 yySeconds = 0;
 123                 if ($2 == tPM)
 124                         yyHour += 12;
 125         }
 126         | bare_time {
 127                 /* "7:12:18" "19:17" */
 128         }
 129         | bare_time tAMPM {
 130                 /* "7:12pm", "12:20:13am" */
 131                 if (yyHour == 12)
 132                         yyHour = 0;
 133                 if ($2 == tPM)
 134                         yyHour += 12;
 135         }
 136         | bare_time  '+' tUNUMBER {
 137                 /* "7:14+0700" */
 138                 yyDSTmode = DSToff;
 139                 yyTimezone = - ($3 % 100 + ($3 / 100) * 60);
 140         }
 141         | bare_time '-' tUNUMBER {
 142                 /* "19:14:12-0530" */
 143                 yyDSTmode = DSToff;
 144                 yyTimezone = + ($3 % 100 + ($3 / 100) * 60);
 145         }
 146         ;
 147
 148 bare_time : tUNUMBER ':' tUNUMBER {
 149                 yyHour = $1;
 150                 yyMinutes = $3;
 151                 yySeconds = 0;
 152         }
 153         | tUNUMBER ':' tUNUMBER ':' tUNUMBER {
 154                 yyHour = $1;
 155                 yyMinutes = $3;
 156                 yySeconds = $5;
 157         }
 158         ;
 159
 160 zone    : tZONE {
 161                 yyTimezone = $1;
 162                 yyDSTmode = DSToff;
 163         }
 164         | tDAYZONE {
 165                 yyTimezone = $1;
 166                 yyDSTmode = DSTon;
 167         }
 168         | tZONE tDST {
 169                 yyTimezone = $1;
 170                 yyDSTmode = DSTon;
 171         }
 172         ;
 173
 174 day     : tDAY {
 175                 yyDayOrdinal = 1;
 176                 yyDayNumber = $1;
 177         }
 178         | tDAY ',' {
 179                 /* "tue," "wednesday," */
 180                 yyDayOrdinal = 1;
 181                 yyDayNumber = $1;
 182         }
 183         | tUNUMBER tDAY {
 184                 /* "second tues" "3 wed" */
 185                 yyDayOrdinal = $1;
 186                 yyDayNumber = $2;
 187         }
 188         ;
 189
 190 date    : tUNUMBER '/' tUNUMBER {
 191                 /* "1/15" */
 192                 yyMonth = $1;
 193                 yyDay = $3;
 194         }
 195         | tUNUMBER '/' tUNUMBER '/' tUNUMBER {
 196                 if ($1 >= 13) {
 197                         /* First number is big:  2004/01/29, 99/02/17 */
 198                         yyYear = $1;
 199                         yyMonth = $3;
 200                         yyDay = $5;
 201                 } else if (($5 >= 13) || ($3 >= 13)) {
 202                         /* Last number is big:  01/07/98 */
 203                         /* Middle number is big:  01/29/04 */
 204                         yyMonth = $1;
 205                         yyDay = $3;
 206                         yyYear = $5;
 207                 } else {
 208                         /* No significant clues: 02/03/04 */
 209                         yyMonth = $1;
 210                         yyDay = $3;
 211                         yyYear = $5;
 212                 }
 213         }
 214         | tUNUMBER '-' tUNUMBER '-' tUNUMBER {
 215                 /* ISO 8601 format.  yyyy-mm-dd.  */
 216                 yyYear = $1;
 217                 yyMonth = $3;
 218                 yyDay = $5;
 219         }
 220         | tUNUMBER '-' tMONTH '-' tUNUMBER {
 221                 if ($1 > 31) {
 222                         /* e.g. 1992-Jun-17 */
 223                         yyYear = $1;
 224                         yyMonth = $3;
 225                         yyDay = $5;
 226                 } else {
 227                         /* e.g. 17-JUN-1992.  */
 228                         yyDay = $1;
 229                         yyMonth = $3;
 230                         yyYear = $5;
 231                 }
 232         }
 233         | tMONTH tUNUMBER {
 234                 /* "May 3" */
 235                 yyMonth = $1;
 236                 yyDay = $2;
 237         }
 238         | tMONTH tUNUMBER ',' tUNUMBER {
 239                 /* "June 17, 2001" */
 240                 yyMonth = $1;
 241                 yyDay = $2;
 242                 yyYear = $4;
 243         }
 244         | tUNUMBER tMONTH {
 245                 /* "12 Sept" */
 246                 yyDay = $1;
 247                 yyMonth = $2;
 248         }
 249         | tUNUMBER tMONTH tUNUMBER {
 250                 /* "12 Sept 1997" */
 251                 yyDay = $1;
 252                 yyMonth = $2;
 253                 yyYear = $3;
 254         }
 255         ;
 256
 257 rel     : relunit tAGO {
 258                 yyRelSeconds = -yyRelSeconds;
 259                 yyRelMonth = -yyRelMonth;
 260         }
 261         | relunit
 262         ;
 263
 264 relunit : '-' tUNUMBER tSEC_UNIT {
 265                 /* "-3 hours" */
 266                 yyRelSeconds -= $2 * $3;
 267         }
 268         | '+' tUNUMBER tSEC_UNIT {
 269                 /* "+1 minute" */
 270                 yyRelSeconds += $2 * $3;
 271         }
 272         | tUNUMBER tSEC_UNIT {
 273                 /* "1 day" */
 274                 yyRelSeconds += $1 * $2;
 275         }
 276         | tSEC_UNIT {
 277                 /* "hour" */
 278                 yyRelSeconds += $1;
 279         }
 280         | '-' tUNUMBER tMONTH_UNIT {
 281                 /* "-3 months" */
 282                 yyRelMonth -= $2 * $3;
 283         }
 284         | '+' tUNUMBER tMONTH_UNIT {
 285                 /* "+5 years" */
 286                 yyRelMonth += $2 * $3;
 287         }
 288         | tUNUMBER tMONTH_UNIT {
 289                 /* "2 years" */
 290                 yyRelMonth += $1 * $2;
 291         }
 292         | tMONTH_UNIT {
 293                 /* "6 months" */
 294                 yyRelMonth += $1;
 295         }
 296         ;
 297
 298 number  : tUNUMBER {
 299                 if (yyHaveTime && yyHaveDate && !yyHaveRel)
 300                         yyYear = $1;
 301                 else {
 302                         if($1>10000) {
 303                                 /* "20040301" */
 304                                 yyHaveDate++;
 305                                 yyDay= ($1)%100;
 306                                 yyMonth= ($1/100)%100;
 307                                 yyYear = $1/10000;
 308                         }
 309                         else {
 310                                 /* "513" is same as "5:13" */
 311                                 yyHaveTime++;
 312                                 if ($1 < 100) {
 313                                         yyHour = $1;
 314                                         yyMinutes = 0;
 315                                 }
 316                                 else {
 317                                         yyHour = $1 / 100;
 318                                         yyMinutes = $1 % 100;
 319                                 }
 320                                 yySeconds = 0;
 321                         }
 322                 }
 323         }
 324         ;
 325
 326
 327 %%
 328
 329 static struct TABLE {
 330         size_t          abbrev;
 331         const char      *name;
 332         int             type;
 333         time_t          value;
 334 } const TimeWords[] = {
 335         /* am/pm */
 336         { 0, "am",              tAMPM,  tAM },
 337         { 0, "pm",              tAMPM,  tPM },
 338
 339         /* Month names. */
 340         { 3, "january",         tMONTH,  1 },
 341         { 3, "february",        tMONTH,  2 },
 342         { 3, "march",           tMONTH,  3 },
 343         { 3, "april",           tMONTH,  4 },
 344         { 3, "may",             tMONTH,  5 },
 345         { 3, "june",            tMONTH,  6 },
 346         { 3, "july",            tMONTH,  7 },
 347         { 3, "august",          tMONTH,  8 },
 348         { 3, "september",       tMONTH,  9 },
 349         { 3, "october",         tMONTH, 10 },
 350         { 3, "november",        tMONTH, 11 },
 351         { 3, "december",        tMONTH, 12 },
 352
 353         /* Days of the week. */
 354         { 2, "sunday",          tDAY, 0 },
 355         { 3, "monday",          tDAY, 1 },
 356         { 2, "tuesday",         tDAY, 2 },
 357         { 3, "wednesday",       tDAY, 3 },
 358         { 2, "thursday",        tDAY, 4 },
 359         { 2, "friday",          tDAY, 5 },
 360         { 2, "saturday",        tDAY, 6 },
 361
 362         /* Timezones: Offsets are in minutes. */
 363         { 0, "gmt",  tZONE,     HOUR( 0) }, /* Greenwich Mean */
 364         { 0, "ut",   tZONE,     HOUR( 0) }, /* Universal (Coordinated) */
 365         { 0, "utc",  tZONE,     HOUR( 0) },
 366         { 0, "wet",  tZONE,     HOUR( 0) }, /* Western European */
 367         { 0, "bst",  tDAYZONE,  HOUR( 0) }, /* British Summer */
 368         { 0, "wat",  tZONE,     HOUR( 1) }, /* West Africa */
 369         { 0, "at",   tZONE,     HOUR( 2) }, /* Azores */
 370         /* { 0, "bst", tZONE, HOUR( 3) }, */ /* Brazil Standard: Conflict */
 371         /* { 0, "gst", tZONE, HOUR( 3) }, */ /* Greenland Standard: Conflict*/
 372         { 0, "nft",  tZONE,     HOUR(3)+30 }, /* Newfoundland */
 373         { 0, "nst",  tZONE,     HOUR(3)+30 }, /* Newfoundland Standard */
 374         { 0, "ndt",  tDAYZONE,  HOUR(3)+30 }, /* Newfoundland Daylight */
 375         { 0, "ast",  tZONE,     HOUR( 4) }, /* Atlantic Standard */
 376         { 0, "adt",  tDAYZONE,  HOUR( 4) }, /* Atlantic Daylight */
 377         { 0, "est",  tZONE,     HOUR( 5) }, /* Eastern Standard */
 378         { 0, "edt",  tDAYZONE,  HOUR( 5) }, /* Eastern Daylight */
 379         { 0, "cst",  tZONE,     HOUR( 6) }, /* Central Standard */
 380         { 0, "cdt",  tDAYZONE,  HOUR( 6) }, /* Central Daylight */
 381         { 0, "mst",  tZONE,     HOUR( 7) }, /* Mountain Standard */
 382         { 0, "mdt",  tDAYZONE,  HOUR( 7) }, /* Mountain Daylight */
 383         { 0, "pst",  tZONE,     HOUR( 8) }, /* Pacific Standard */
 384         { 0, "pdt",  tDAYZONE,  HOUR( 8) }, /* Pacific Daylight */
 385         { 0, "yst",  tZONE,     HOUR( 9) }, /* Yukon Standard */
 386         { 0, "ydt",  tDAYZONE,  HOUR( 9) }, /* Yukon Daylight */
 387         { 0, "hst",  tZONE,     HOUR(10) }, /* Hawaii Standard */
 388         { 0, "hdt",  tDAYZONE,  HOUR(10) }, /* Hawaii Daylight */
 389         { 0, "cat",  tZONE,     HOUR(10) }, /* Central Alaska */
 390         { 0, "ahst", tZONE,     HOUR(10) }, /* Alaska-Hawaii Standard */
 391         { 0, "nt",   tZONE,     HOUR(11) }, /* Nome */
 392         { 0, "idlw", tZONE,     HOUR(12) }, /* Intl Date Line West */
 393         { 0, "cet",  tZONE,     -HOUR(1) }, /* Central European */
 394         { 0, "met",  tZONE,     -HOUR(1) }, /* Middle European */
 395         { 0, "mewt", tZONE,     -HOUR(1) }, /* Middle European Winter */
 396         { 0, "mest", tDAYZONE,  -HOUR(1) }, /* Middle European Summer */
 397         { 0, "swt",  tZONE,     -HOUR(1) }, /* Swedish Winter */
 398         { 0, "sst",  tDAYZONE,  -HOUR(1) }, /* Swedish Summer */
 399         { 0, "fwt",  tZONE,     -HOUR(1) }, /* French Winter */
 400         { 0, "fst",  tDAYZONE,  -HOUR(1) }, /* French Summer */
 401         { 0, "eet",  tZONE,     -HOUR(2) }, /* Eastern Eur, USSR Zone 1 */
 402         { 0, "bt",   tZONE,     -HOUR(3) }, /* Baghdad, USSR Zone 2 */
 403         { 0, "it",   tZONE,     -HOUR(3)-30 },/* Iran */
 404         { 0, "zp4",  tZONE,     -HOUR(4) }, /* USSR Zone 3 */
 405         { 0, "zp5",  tZONE,     -HOUR(5) }, /* USSR Zone 4 */
 406         { 0, "ist",  tZONE,     -HOUR(5)-30 },/* Indian Standard */
 407         { 0, "zp6",  tZONE,     -HOUR(6) }, /* USSR Zone 5 */
 408         /* { 0, "nst",  tZONE, -HOUR(6.5) }, */ /* North Sumatra: Conflict */
 409         /* { 0, "sst", tZONE, -HOUR(7) }, */ /* So Sumatra, USSR 6: Conflict */
 410         { 0, "wast", tZONE,     -HOUR(7) }, /* West Australian Standard */
 411         { 0, "wadt", tDAYZONE,  -HOUR(7) }, /* West Australian Daylight */
 412         { 0, "jt",   tZONE,     -HOUR(7)-30 },/* Java (3pm in Cronusland!)*/
 413         { 0, "cct",  tZONE,     -HOUR(8) }, /* China Coast, USSR Zone 7 */
 414         { 0, "jst",  tZONE,     -HOUR(9) }, /* Japan Std, USSR Zone 8 */
 415         { 0, "cast", tZONE,     -HOUR(9)-30 },/* Central Australian Std */
 416         { 0, "cadt", tDAYZONE,  -HOUR(9)-30 },/* Central Australian Daylt */
 417         { 0, "east", tZONE,     -HOUR(10) }, /* Eastern Australian Std */
 418         { 0, "eadt", tDAYZONE,  -HOUR(10) }, /* Eastern Australian Daylt */
 419         { 0, "gst",  tZONE,     -HOUR(10) }, /* Guam Std, USSR Zone 9 */
 420         { 0, "nzt",  tZONE,     -HOUR(12) }, /* New Zealand */
 421         { 0, "nzst", tZONE,     -HOUR(12) }, /* New Zealand Standard */
 422         { 0, "nzdt", tDAYZONE,  -HOUR(12) }, /* New Zealand Daylight */
 423         { 0, "idle", tZONE,     -HOUR(12) }, /* Intl Date Line East */
 424
 425         { 0, "dst",  tDST,              0 },
 426
 427         /* Time units. */
 428         { 4, "years",           tMONTH_UNIT,    12 },
 429         { 5, "months",          tMONTH_UNIT,    1 },
 430         { 9, "fortnights",      tSEC_UNIT,      14 * 24 * 60 * 60 },
 431         { 4, "weeks",           tSEC_UNIT,      7 * 24 * 60 * 60 },
 432         { 3, "days",            tSEC_UNIT,      1 * 24 * 60 * 60 },
 433         { 4, "hours",           tSEC_UNIT,      60 * 60 },
 434         { 3, "minutes",         tSEC_UNIT,      60 },
 435         { 3, "seconds",         tSEC_UNIT,      1 },
 436
 437         /* Relative-time words. */
 438         { 0, "tomorrow",        tSEC_UNIT,      1 * 24 * 60 * 60 },
 439         { 0, "yesterday",       tSEC_UNIT,      -1 * 24 * 60 * 60 },
 440         { 0, "today",           tSEC_UNIT,      0 },
 441         { 0, "now",             tSEC_UNIT,      0 },
 442         { 0, "last",            tUNUMBER,       -1 },
 443         { 0, "this",            tSEC_UNIT,      0 },
 444         { 0, "next",            tUNUMBER,       2 },
 445         { 0, "first",           tUNUMBER,       1 },
 446         { 0, "1st",             tUNUMBER,       1 },
 447 /*      { 0, "second",          tUNUMBER,       2 }, */
 448         { 0, "2nd",             tUNUMBER,       2 },
 449         { 0, "third",           tUNUMBER,       3 },
 450         { 0, "3rd",             tUNUMBER,       3 },
 451         { 0, "fourth",          tUNUMBER,       4 },
 452         { 0, "4th",             tUNUMBER,       4 },
 453         { 0, "fifth",           tUNUMBER,       5 },
 454         { 0, "5th",             tUNUMBER,       5 },
 455         { 0, "sixth",           tUNUMBER,       6 },
 456         { 0, "seventh",         tUNUMBER,       7 },
 457         { 0, "eighth",          tUNUMBER,       8 },
 458         { 0, "ninth",           tUNUMBER,       9 },
 459         { 0, "tenth",           tUNUMBER,       10 },
 460         { 0, "eleventh",        tUNUMBER,       11 },
 461         { 0, "twelfth",         tUNUMBER,       12 },
 462         { 0, "ago",             tAGO,           1 },
 463
 464         /* Military timezones. */
 465         { 0, "a",       tZONE,  HOUR(  1) },
 466         { 0, "b",       tZONE,  HOUR(  2) },
 467         { 0, "c",       tZONE,  HOUR(  3) },
 468         { 0, "d",       tZONE,  HOUR(  4) },
 469         { 0, "e",       tZONE,  HOUR(  5) },
 470         { 0, "f",       tZONE,  HOUR(  6) },
 471         { 0, "g",       tZONE,  HOUR(  7) },
 472         { 0, "h",       tZONE,  HOUR(  8) },
 473         { 0, "i",       tZONE,  HOUR(  9) },
 474         { 0, "k",       tZONE,  HOUR( 10) },
 475         { 0, "l",       tZONE,  HOUR( 11) },
 476         { 0, "m",       tZONE,  HOUR( 12) },
 477         { 0, "n",       tZONE,  HOUR(- 1) },
 478         { 0, "o",       tZONE,  HOUR(- 2) },
 479         { 0, "p",       tZONE,  HOUR(- 3) },
 480         { 0, "q",       tZONE,  HOUR(- 4) },
 481         { 0, "r",       tZONE,  HOUR(- 5) },
 482         { 0, "s",       tZONE,  HOUR(- 6) },
 483         { 0, "t",       tZONE,  HOUR(- 7) },
 484         { 0, "u",       tZONE,  HOUR(- 8) },
 485         { 0, "v",       tZONE,  HOUR(- 9) },
 486         { 0, "w",       tZONE,  HOUR(-10) },
 487         { 0, "x",       tZONE,  HOUR(-11) },
 488         { 0, "y",       tZONE,  HOUR(-12) },
 489         { 0, "z",       tZONE,  HOUR(  0) },
 490
 491         /* End of table. */
 492         { 0, NULL,      0,      0 }
 493 };
 494
 495 \f
 496
 497
 498 /* ARGSUSED */
 499 static int
 500 yyerror(const char *s)
 501 {
 502         (void)s;
 503         return 0;
 504 }
 505
 506 static time_t
 507 ToSeconds(time_t Hours, time_t Minutes, time_t Seconds)
 508 {
 509         if (Minutes < 0 || Minutes > 59 || Seconds < 0 || Seconds > 59)
 510                 return -1;
 511         if (Hours < 0 || Hours > 23)
 512                 return -1;
 513         return (Hours * 60L + Minutes) * 60L + Seconds;
 514 }
 515
 516
 517 /* Year is either
 518  * A number from 0 to 99, which means a year from 1970 to 2069, or
 519  * The actual year (>=100).  */
 520 static time_t
 521 Convert(time_t Month, time_t Day, time_t Year,
 522         time_t Hours, time_t Minutes, time_t Seconds, DSTMODE DSTmode)
 523 {
 524         static int DaysInMonth[12] = {
 525                 31, 0, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
 526         };
 527         time_t  tod;
 528         time_t  Julian;
 529         int     i;
 530
 531         if (Year < 69)
 532                 Year += 2000;
 533         else if (Year < 100)
 534                 Year += 1900;
 535         DaysInMonth[1] = Year % 4 == 0 && (Year % 100 != 0 || Year % 400 == 0)
 536             ? 29 : 28;
 537         /* Checking for 2038 bogusly assumes that time_t is 32 bits.  But
 538            I'm too lazy to try to check for time_t overflow in another way.  */
 539         if (Year < EPOCH || Year > 2038
 540             || Month < 1 || Month > 12
 541             /* Lint fluff:  "conversion from long may lose accuracy" */
 542             || Day < 1 || Day > DaysInMonth[(int)--Month])
 543                 return -1;
 544
 545         Julian = Day - 1;
 546         for (i = 0; i < Month; i++)
 547                 Julian += DaysInMonth[i];
 548         for (i = EPOCH; i < Year; i++)
 549                 Julian += 365 + (i % 4 == 0);
 550         Julian *= SECSPERDAY;
 551         Julian += yyTimezone * 60L;
 552         if ((tod = ToSeconds(Hours, Minutes, Seconds)) < 0)
 553                 return -1;
 554         Julian += tod;
 555         if (DSTmode == DSTon
 556             || (DSTmode == DSTmaybe && localtime(&Julian)->tm_isdst))
 557                 Julian -= 60 * 60;
 558         return Julian;
 559 }
 560
 561
 562 static time_t
 563 DSTcorrect(time_t Start, time_t Future)
 564 {
 565         time_t  StartDay;
 566         time_t  FutureDay;
 567
 568         StartDay = (localtime(&Start)->tm_hour + 1) % 24;
 569         FutureDay = (localtime(&Future)->tm_hour + 1) % 24;
 570         return (Future - Start) + (StartDay - FutureDay) * 60L * 60L;
 571 }
 572
 573
 574 static time_t
 575 RelativeDate(time_t Start, time_t DayOrdinal, time_t DayNumber)
 576 {
 577         struct tm       *tm;
 578         time_t  now;
 579
 580         now = Start;
 581         tm = localtime(&now);
 582         now += SECSPERDAY * ((DayNumber - tm->tm_wday + 7) % 7);
 583         now += 7 * SECSPERDAY * (DayOrdinal <= 0 ? DayOrdinal : DayOrdinal - 1);
 584         return DSTcorrect(Start, now);
 585 }
 586
 587
 588 static time_t
 589 RelativeMonth(time_t Start, time_t RelMonth)
 590 {
 591         struct tm       *tm;
 592         time_t  Month;
 593         time_t  Year;
 594
 595         if (RelMonth == 0)
 596                 return 0;
 597         tm = localtime(&Start);
 598         Month = 12 * (tm->tm_year + 1900) + tm->tm_mon + RelMonth;
 599         Year = Month / 12;
 600         Month = Month % 12 + 1;
 601         return DSTcorrect(Start,
 602             Convert(Month, (time_t)tm->tm_mday, Year,
 603                 (time_t)tm->tm_hour, (time_t)tm->tm_min, (time_t)tm->tm_sec,
 604                 DSTmaybe));
 605 }
 606
 607 static int
 608 yylex(void)
 609 {
 610         char    c;
 611         char    buff[64];
 612
 613         for ( ; ; ) {
 614                 while (isspace(*yyInput))
 615                         yyInput++;
 616
 617                 /* Skip parenthesized comments. */
 618                 if (*yyInput == '(') {
 619                         int Count = 0;
 620                         do {
 621                                 c = *yyInput++;
 622                                 if (c == '\0')
 623                                         return c;
 624                                 if (c == '(')
 625                                         Count++;
 626                                 else if (c == ')')
 627                                         Count--;
 628                         } while (Count > 0);
 629                         continue;
 630                 }
 631
 632                 /* Try the next token in the word table first. */
 633                 /* This allows us to match "2nd", for example. */
 634                 {
 635                         char *src = yyInput;
 636                         const struct TABLE *tp;
 637                         unsigned i = 0;
 638
 639                         /* Force to lowercase and strip '.' characters. */
 640                         while (*src != '\0'
 641                             && (isalnum(*src) || *src == '.')
 642                             && i < sizeof(buff)-1) {
 643                                 if (*src != '.') {
 644                                         if (isupper(*src))
 645                                                 buff[i++] = tolower(*src);
 646                                         else
 647                                                 buff[i++] = *src;
 648                                 }
 649                                 src++;
 650                         }
 651                         buff[i++] = '\0';
 652
 653                         /*
 654                          * Find the first match.  If the word can be
 655                          * abbreviated, make sure we match at least
 656                          * the minimum abbreviation.
 657                          */
 658                         for (tp = TimeWords; tp->name; tp++) {
 659                                 size_t abbrev = tp->abbrev;
 660                                 if (abbrev == 0)
 661                                         abbrev = strlen(tp->name);
 662                                 if (strlen(buff) >= abbrev
 663                                     && strncmp(tp->name, buff, strlen(buff))
 664                                         == 0) {
 665                                         /* Skip over token. */
 666                                         yyInput = src;
 667                                         /* Return the match. */
 668                                         yylval.Number = tp->value;
 669                                         return tp->type;
 670                                 }
 671                         }
 672                 }
 673
 674                 /*
 675                  * Not in the word table, maybe it's a number.  Note:
 676                  * Because '-' and '+' have other special meanings, I
 677                  * don't deal with signed numbers here.
 678                  */
 679                 if (isdigit(c = *yyInput)) {
 680                         for (yylval.Number = 0; isdigit(c = *yyInput++); )
 681                                 yylval.Number = 10 * yylval.Number + c - '0';
 682                         yyInput--;
 683                         return (tUNUMBER);
 684                 }
 685
 686                 return (*yyInput++);
 687         }
 688 }
 689
 690 #define TM_YEAR_ORIGIN 1900
 691
 692 /* Yield A - B, measured in seconds.  */
 693 static long
 694 difftm (struct tm *a, struct tm *b)
 695 {
 696         int ay = a->tm_year + (TM_YEAR_ORIGIN - 1);
 697         int by = b->tm_year + (TM_YEAR_ORIGIN - 1);
 698         int days = (
 699                 /* difference in day of year */
 700                 a->tm_yday - b->tm_yday
 701                 /* + intervening leap days */
 702                 +  ((ay >> 2) - (by >> 2))
 703                 -  (ay/100 - by/100)
 704                 +  ((ay/100 >> 2) - (by/100 >> 2))
 705                 /* + difference in years * 365 */
 706                 +  (long)(ay-by) * 365
 707                 );
 708         return (60*(60*(24*days + (a->tm_hour - b->tm_hour))
 709             + (a->tm_min - b->tm_min))
 710             + (a->tm_sec - b->tm_sec));
 711 }
 712
 713 time_t
 714 get_date(char *p)
 715 {
 716         struct tm       *tm;
 717         struct tm       gmt, *gmt_ptr;
 718         time_t          Start;
 719         time_t          tod;
 720         time_t          nowtime;
 721         long            tzone;
 722
 723         memset(&gmt, 0, sizeof(gmt));
 724         yyInput = p;
 725
 726         (void)time (&nowtime);
 727
 728         gmt_ptr = gmtime (&nowtime);
 729         if (gmt_ptr != NULL) {
 730                 /* Copy, in case localtime and gmtime use the same buffer. */
 731                 gmt = *gmt_ptr;
 732         }
 733
 734         if (! (tm = localtime (&nowtime)))
 735                 return -1;
 736
 737         if (gmt_ptr != NULL)
 738                 tzone = difftm (&gmt, tm) / 60;
 739         else
 740                 /* This system doesn't understand timezones; fake it. */
 741                 tzone = 0;
 742         if(tm->tm_isdst)
 743                 tzone += 60;
 744
 745         yyYear = tm->tm_year + 1900;
 746         yyMonth = tm->tm_mon + 1;
 747         yyDay = tm->tm_mday;
 748         yyTimezone = tzone;
 749         yyDSTmode = DSTmaybe;
 750         yyHour = 0;
 751         yyMinutes = 0;
 752         yySeconds = 0;
 753         yyRelSeconds = 0;
 754         yyRelMonth = 0;
 755         yyHaveDate = 0;
 756         yyHaveDay = 0;
 757         yyHaveRel = 0;
 758         yyHaveTime = 0;
 759         yyHaveZone = 0;
 760
 761         if (yyparse()
 762             || yyHaveTime > 1 || yyHaveZone > 1
 763             || yyHaveDate > 1 || yyHaveDay > 1)
 764                 return -1;
 765
 766         if (yyHaveDate || yyHaveTime || yyHaveDay) {
 767                 Start = Convert(yyMonth, yyDay, yyYear,
 768                     yyHour, yyMinutes, yySeconds, yyDSTmode);
 769                 if (Start < 0)
 770                         return -1;
 771         } else {
 772                 Start = nowtime;
 773                 if (!yyHaveRel)
 774                         Start -= ((tm->tm_hour * 60L + tm->tm_min) * 60L) + tm->tm_sec;
 775         }
 776
 777         Start += yyRelSeconds;
 778         Start += RelativeMonth(Start, yyRelMonth);
 779
 780         if (yyHaveDay && !yyHaveDate) {
 781                 tod = RelativeDate(Start, yyDayOrdinal, yyDayNumber);
 782                 Start += tod;
 783         }
 784
 785         /* Have to do *something* with a legitimate -1 so it's
 786          * distinguishable from the error return value.  (Alternately
 787          * could set errno on error.) */
 788         return Start == -1 ? 0 : Start;
 789 }
 790
 791
 792 #if     defined(TEST)
 793
 794 /* ARGSUSED */
 795 int
 796 main(int argc, char **argv)
 797 {
 798     time_t      d;
 799
 800     while (*++argv != NULL) {
 801             (void)printf("Input: %s\n", *argv);
 802             d = get_date(*argv);
 803             if (d == -1)
 804                     (void)printf("Bad format - couldn't convert.\n");
 805             else
 806                     (void)printf("Output: %s\n", ctime(&d));
 807     }
 808     exit(0);
 809     /* NOTREACHED */
 810 }
 811 #endif  /* defined(TEST) */