lib/libc/time/strptime.c

   1 /*      $NetBSD: strptime.c,v 1.35 2009/12/14 20:45:02 matt Exp $       */
   2
   3 /*-
   4  * Copyright (c) 1997, 1998, 2005, 2008 The NetBSD Foundation, Inc.
   5  * All rights reserved.
   6  *
   7  * This code was contributed to The NetBSD Foundation by Klaus Klein.
   8  * Heavily optimised by David Laight
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  29  * POSSIBILITY OF SUCH DAMAGE.
  30  */
  31
  32 #include <sys/cdefs.h>
  33 #if defined(LIBC_SCCS) && !defined(lint)
  34 __RCSID("$NetBSD: strptime.c,v 1.35 2009/12/14 20:45:02 matt Exp $");
  35 #endif
  36
  37 #include "namespace.h"
  38 #include <sys/localedef.h>
  39 #include <ctype.h>
  40 #include <locale.h>
  41 #include <string.h>
  42 #include <time.h>
  43 #include <tzfile.h>
  44 #include "private.h"
  45
  46 #ifdef __weak_alias
  47 __weak_alias(strptime,_strptime)
  48 #endif
  49
  50 #define _ctloc(x)               (_CurrentTimeLocale->x)
  51
  52 /*
  53  * We do not implement alternate representations. However, we always
  54  * check whether a given modifier is allowed for a certain conversion.
  55  */
  56 #define ALT_E                   0x01
  57 #define ALT_O                   0x02
  58 #define LEGAL_ALT(x)            { if (alt_format & ~(x)) return NULL; }
  59
  60 static char gmt[] = { "GMT" };
  61 static char utc[] = { "UTC" };
  62 /* RFC-822/RFC-2822 */
  63 static const char * const nast[5] = {
  64        "EST",    "CST",    "MST",    "PST",    "\0\0\0"
  65 };
  66 static const char * const nadt[5] = {
  67        "EDT",    "CDT",    "MDT",    "PDT",    "\0\0\0"
  68 };
  69
  70 static const u_char *conv_num(const unsigned char *, int *, uint, uint);
  71 static const u_char *find_string(const u_char *, int *, const char * const *,
  72         const char * const *, int);
  73
  74
  75 char *
  76 strptime(const char *buf, const char *fmt, struct tm *tm)
  77 {
  78         unsigned char c;
  79         const unsigned char *bp, *ep;
  80         int alt_format, i, split_year = 0, neg = 0, offs;
  81         const char *new_fmt;
  82
  83         bp = (const u_char *)buf;
  84
  85         while (bp != NULL && (c = *fmt++) != '\0') {
  86                 /* Clear `alternate' modifier prior to new conversion. */
  87                 alt_format = 0;
  88                 i = 0;
  89
  90                 /* Eat up white-space. */
  91                 if (isspace(c)) {
  92                         while (isspace(*bp))
  93                                 bp++;
  94                         continue;
  95                 }
  96
  97                 if (c != '%')
  98                         goto literal;
  99
 100
 101 again:          switch (c = *fmt++) {
 102                 case '%':       /* "%%" is converted to "%". */
 103 literal:
 104                         if (c != *bp++)
 105                                 return NULL;
 106                         LEGAL_ALT(0);
 107                         continue;
 108
 109                 /*
 110                  * "Alternative" modifiers. Just set the appropriate flag
 111                  * and start over again.
 112                  */
 113                 case 'E':       /* "%E?" alternative conversion modifier. */
 114                         LEGAL_ALT(0);
 115                         alt_format |= ALT_E;
 116                         goto again;
 117
 118                 case 'O':       /* "%O?" alternative conversion modifier. */
 119                         LEGAL_ALT(0);
 120                         alt_format |= ALT_O;
 121                         goto again;
 122
 123                 /*
 124                  * "Complex" conversion rules, implemented through recursion.
 125                  */
 126                 case 'c':       /* Date and time, using the locale's format. */
 127                         new_fmt = _ctloc(d_t_fmt);
 128                         goto recurse;
 129
 130                 case 'D':       /* The date as "%m/%d/%y". */
 131                         new_fmt = "%m/%d/%y";
 132                         LEGAL_ALT(0);
 133                         goto recurse;
 134
 135                 case 'F':       /* The date as "%Y-%m-%d". */
 136                         new_fmt = "%Y-%m-%d";
 137                         LEGAL_ALT(0);
 138                         goto recurse;
 139
 140                 case 'R':       /* The time as "%H:%M". */
 141                         new_fmt = "%H:%M";
 142                         LEGAL_ALT(0);
 143                         goto recurse;
 144
 145                 case 'r':       /* The time in 12-hour clock representation. */
 146                         new_fmt =_ctloc(t_fmt_ampm);
 147                         LEGAL_ALT(0);
 148                         goto recurse;
 149
 150                 case 'T':       /* The time as "%H:%M:%S". */
 151                         new_fmt = "%H:%M:%S";
 152                         LEGAL_ALT(0);
 153                         goto recurse;
 154
 155                 case 'X':       /* The time, using the locale's format. */
 156                         new_fmt =_ctloc(t_fmt);
 157                         goto recurse;
 158
 159                 case 'x':       /* The date, using the locale's format. */
 160                         new_fmt =_ctloc(d_fmt);
 161                     recurse:
 162                         bp = (const u_char *)strptime((const char *)bp,
 163                                                             new_fmt, tm);
 164                         LEGAL_ALT(ALT_E);
 165                         continue;
 166
 167                 /*
 168                  * "Elementary" conversion rules.
 169                  */
 170                 case 'A':       /* The day of week, using the locale's form. */
 171                 case 'a':
 172                         bp = find_string(bp, &tm->tm_wday, _ctloc(day),
 173                                         _ctloc(abday), 7);
 174                         LEGAL_ALT(0);
 175                         continue;
 176
 177                 case 'B':       /* The month, using the locale's form. */
 178                 case 'b':
 179                 case 'h':
 180                         bp = find_string(bp, &tm->tm_mon, _ctloc(mon),
 181                                         _ctloc(abmon), 12);
 182                         LEGAL_ALT(0);
 183                         continue;
 184
 185                 case 'C':       /* The century number. */
 186                         i = 20;
 187                         bp = conv_num(bp, &i, 0, 99);
 188
 189                         i = i * 100 - TM_YEAR_BASE;
 190                         if (split_year)
 191                                 i += tm->tm_year % 100;
 192                         split_year = 1;
 193                         tm->tm_year = i;
 194                         LEGAL_ALT(ALT_E);
 195                         continue;
 196
 197                 case 'd':       /* The day of month. */
 198                 case 'e':
 199                         bp = conv_num(bp, &tm->tm_mday, 1, 31);
 200                         LEGAL_ALT(ALT_O);
 201                         continue;
 202
 203                 case 'k':       /* The hour (24-hour clock representation). */
 204                         LEGAL_ALT(0);
 205                         /* FALLTHROUGH */
 206                 case 'H':
 207                         bp = conv_num(bp, &tm->tm_hour, 0, 23);
 208                         LEGAL_ALT(ALT_O);
 209                         continue;
 210
 211                 case 'l':       /* The hour (12-hour clock representation). */
 212                         LEGAL_ALT(0);
 213                         /* FALLTHROUGH */
 214                 case 'I':
 215                         bp = conv_num(bp, &tm->tm_hour, 1, 12);
 216                         if (tm->tm_hour == 12)
 217                                 tm->tm_hour = 0;
 218                         LEGAL_ALT(ALT_O);
 219                         continue;
 220
 221                 case 'j':       /* The day of year. */
 222                         i = 1;
 223                         bp = conv_num(bp, &i, 1, 366);
 224                         tm->tm_yday = i - 1;
 225                         LEGAL_ALT(0);
 226                         continue;
 227
 228                 case 'M':       /* The minute. */
 229                         bp = conv_num(bp, &tm->tm_min, 0, 59);
 230                         LEGAL_ALT(ALT_O);
 231                         continue;
 232
 233                 case 'm':       /* The month. */
 234                         i = 1;
 235                         bp = conv_num(bp, &i, 1, 12);
 236                         tm->tm_mon = i - 1;
 237                         LEGAL_ALT(ALT_O);
 238                         continue;
 239
 240                 case 'p':       /* The locale's equivalent of AM/PM. */
 241                         bp = find_string(bp, &i, _ctloc(am_pm), NULL, 2);
 242                         if (tm->tm_hour > 11)
 243                                 return NULL;
 244                         tm->tm_hour += i * 12;
 245                         LEGAL_ALT(0);
 246                         continue;
 247
 248                 case 'S':       /* The seconds. */
 249                         bp = conv_num(bp, &tm->tm_sec, 0, 61);
 250                         LEGAL_ALT(ALT_O);
 251                         continue;
 252
 253 #ifndef TIME_MAX
 254 #define TIME_MAX        INT64_MAX
 255 #endif
 256                 case 's':       /* seconds since the epoch */
 257                         {
 258                                 time_t sse = 0;
 259                                 uint64_t rulim = TIME_MAX;
 260
 261                                 if (*bp < '0' || *bp > '9') {
 262                                         bp = NULL;
 263                                         continue;
 264                                 }
 265
 266                                 do {
 267                                         sse *= 10;
 268                                         sse += *bp++ - '0';
 269                                         rulim /= 10;
 270                                 } while ((sse * 10 <= TIME_MAX) &&
 271                                          rulim && *bp >= '0' && *bp <= '9');
 272
 273                                 if (sse < 0 || (uint64_t)sse > TIME_MAX) {
 274                                         bp = NULL;
 275                                         continue;
 276                                 }
 277
 278                                 if (localtime_r(&sse, tm) == NULL)
 279                                         bp = NULL;
 280                         }
 281                         continue;
 282
 283                 case 'U':       /* The week of year, beginning on sunday. */
 284                 case 'W':       /* The week of year, beginning on monday. */
 285                         /*
 286                          * XXX This is bogus, as we can not assume any valid
 287                          * information present in the tm structure at this
 288                          * point to calculate a real value, so just check the
 289                          * range for now.
 290                          */
 291                          bp = conv_num(bp, &i, 0, 53);
 292                          LEGAL_ALT(ALT_O);
 293                          continue;
 294
 295                 case 'w':       /* The day of week, beginning on sunday. */
 296                         bp = conv_num(bp, &tm->tm_wday, 0, 6);
 297                         LEGAL_ALT(ALT_O);
 298                         continue;
 299
 300                 case 'u':       /* The day of week, monday = 1. */
 301                         bp = conv_num(bp, &i, 1, 7);
 302                         tm->tm_wday = i % 7;
 303                         LEGAL_ALT(ALT_O);
 304                         continue;
 305
 306                 case 'g':       /* The year corresponding to the ISO week
 307                                  * number but without the century.
 308                                  */
 309                         bp = conv_num(bp, &i, 0, 99);
 310                         continue;
 311
 312                 case 'G':       /* The year corresponding to the ISO week
 313                                  * number with century.
 314                                  */
 315                         do
 316                                 bp++;
 317                         while (isdigit(*bp));
 318                         continue;
 319
 320                 case 'V':       /* The ISO 8601:1988 week number as decimal */
 321                         bp = conv_num(bp, &i, 0, 53);
 322                         continue;
 323
 324                 case 'Y':       /* The year. */
 325                         i = TM_YEAR_BASE;       /* just for data sanity... */
 326                         bp = conv_num(bp, &i, 0, 9999);
 327                         tm->tm_year = i - TM_YEAR_BASE;
 328                         LEGAL_ALT(ALT_E);
 329                         continue;
 330
 331                 case 'y':       /* The year within 100 years of the epoch. */
 332                         /* LEGAL_ALT(ALT_E | ALT_O); */
 333                         bp = conv_num(bp, &i, 0, 99);
 334
 335                         if (split_year)
 336                                 /* preserve century */
 337                                 i += (tm->tm_year / 100) * 100;
 338                         else {
 339                                 split_year = 1;
 340                                 if (i <= 68)
 341                                         i = i + 2000 - TM_YEAR_BASE;
 342                                 else
 343                                         i = i + 1900 - TM_YEAR_BASE;
 344                         }
 345                         tm->tm_year = i;
 346                         continue;
 347
 348                 case 'Z':
 349                         tzset();
 350                         if (strncmp((const char *)bp, gmt, 3) == 0) {
 351                                 tm->tm_isdst = 0;
 352 #ifdef TM_GMTOFF
 353                                 tm->TM_GMTOFF = 0;
 354 #endif
 355 #ifdef TM_ZONE
 356                                 tm->TM_ZONE = gmt;
 357 #endif
 358                                 bp += 3;
 359                         } else {
 360                                 ep = find_string(bp, &i,
 361                                                  (const char * const *)tzname,
 362                                                   NULL, 2);
 363                                 if (ep != NULL) {
 364                                         tm->tm_isdst = i;
 365 #ifdef TM_GMTOFF
 366                                         tm->TM_GMTOFF = -(timezone);
 367 #endif
 368 #ifdef TM_ZONE
 369                                         tm->TM_ZONE = tzname[i];
 370 #endif
 371                                 }
 372                                 bp = ep;
 373                         }
 374                         continue;
 375
 376                 case 'z':
 377                         /*
 378                          * We recognize all ISO 8601 formats:
 379                          * Z    = Zulu time/UTC
 380                          * [+-]hhmm
 381                          * [+-]hh:mm
 382                          * [+-]hh
 383                          * We recognize all RFC-822/RFC-2822 formats:
 384                          * UT|GMT
 385                          *          North American : UTC offsets
 386                          * E[DS]T = Eastern : -4 | -5
 387                          * C[DS]T = Central : -5 | -6
 388                          * M[DS]T = Mountain: -6 | -7
 389                          * P[DS]T = Pacific : -7 | -8
 390                          *          Military
 391                          * [A-IL-M] = -1 ... -9 (J not used)
 392                          * [N-Y]  = +1 ... +12
 393                          */
 394                         while (isspace(*bp))
 395                                 bp++;
 396
 397                         switch (*bp++) {
 398                         case 'G':
 399                                 if (*bp++ != 'M')
 400                                         return NULL;
 401                                 /*FALLTHROUGH*/
 402                         case 'U':
 403                                 if (*bp++ != 'T')
 404                                         return NULL;
 405                                 /*FALLTHROUGH*/
 406                         case 'Z':
 407                                 tm->tm_isdst = 0;
 408 #ifdef TM_GMTOFF
 409                                 tm->TM_GMTOFF = 0;
 410 #endif
 411 #ifdef TM_ZONE
 412                                 tm->TM_ZONE = utc;
 413 #endif
 414                                 continue;
 415                         case '+':
 416                                 neg = 0;
 417                                 break;
 418                         case '-':
 419                                 neg = 1;
 420                                 break;
 421                         default:
 422                                 --bp;
 423                                 ep = find_string(bp, &i, nast, NULL, 4);
 424                                 if (ep != NULL) {
 425 #ifdef TM_GMTOFF
 426                                         tm->TM_GMTOFF = -5 - i;
 427 #endif
 428 #ifdef TM_ZONE
 429                                         tm->TM_ZONE = __UNCONST(nast[i]);
 430 #endif
 431                                         bp = ep;
 432                                         continue;
 433                                 }
 434                                 ep = find_string(bp, &i, nadt, NULL, 4);
 435                                 if (ep != NULL) {
 436                                         tm->tm_isdst = 1;
 437 #ifdef TM_GMTOFF
 438                                         tm->TM_GMTOFF = -4 - i;
 439 #endif
 440 #ifdef TM_ZONE
 441                                         tm->TM_ZONE = __UNCONST(nadt[i]);
 442 #endif
 443                                         bp = ep;
 444                                         continue;
 445                                 }
 446
 447                                 if ((*bp >= 'A' && *bp <= 'I') ||
 448                                     (*bp >= 'L' && *bp <= 'Y')) {
 449 #ifdef TM_GMTOFF
 450                                         /* Argh! No 'J'! */
 451                                         if (*bp >= 'A' && *bp <= 'I')
 452                                                 tm->TM_GMTOFF =
 453                                                     ('A' - 1) - (int)*bp;
 454                                         else if (*bp >= 'L' && *bp <= 'M')
 455                                                 tm->TM_GMTOFF = 'A' - (int)*bp;
 456                                         else if (*bp >= 'N' && *bp <= 'Y')
 457                                                 tm->TM_GMTOFF = (int)*bp - 'M';
 458 #endif
 459 #ifdef TM_ZONE
 460                                         tm->TM_ZONE = NULL; /* XXX */
 461 #endif
 462                                         bp++;
 463                                         continue;
 464                                 }
 465                                 return NULL;
 466                         }
 467                         offs = 0;
 468                         for (i = 0; i < 4; ) {
 469                                 if (isdigit(*bp)) {
 470                                         offs = offs * 10 + (*bp++ - '0');
 471                                         i++;
 472                                         continue;
 473                                 }
 474                                 if (i == 2 && *bp == ':') {
 475                                         bp++;
 476                                         continue;
 477                                 }
 478                                 break;
 479                         }
 480                         switch (i) {
 481                         case 2:
 482                                 offs *= 100;
 483                                 break;
 484                         case 4:
 485                                 i = offs % 100;
 486                                 if (i >= 60)
 487                                         return NULL;
 488                                 /* Convert minutes into decimal */
 489                                 offs = (offs / 100) * 100 + (i * 50) / 30;
 490                                 break;
 491                         default:
 492                                 return NULL;
 493                         }
 494                         if (neg)
 495                                 offs = -offs;
 496                         tm->tm_isdst = 0;       /* XXX */
 497 #ifdef TM_GMTOFF
 498                         tm->TM_GMTOFF = offs;
 499 #endif
 500 #ifdef TM_ZONE
 501                         tm->TM_ZONE = NULL;     /* XXX */
 502 #endif
 503                         continue;
 504
 505                 /*
 506                  * Miscellaneous conversions.
 507                  */
 508                 case 'n':       /* Any kind of white-space. */
 509                 case 't':
 510                         while (isspace(*bp))
 511                                 bp++;
 512                         LEGAL_ALT(0);
 513                         continue;
 514
 515
 516                 default:        /* Unknown/unsupported conversion. */
 517                         return NULL;
 518                 }
 519         }
 520
 521         return __UNCONST(bp);
 522 }
 523
 524
 525 static const u_char *
 526 conv_num(const unsigned char *buf, int *dest, uint llim, uint ulim)
 527 {
 528         uint result = 0;
 529         unsigned char ch;
 530
 531         /* The limit also determines the number of valid digits. */
 532         uint rulim = ulim;
 533
 534         ch = *buf;
 535         if (ch < '0' || ch > '9')
 536                 return NULL;
 537
 538         do {
 539                 result *= 10;
 540                 result += ch - '0';
 541                 rulim /= 10;
 542                 ch = *++buf;
 543         } while ((result * 10 <= ulim) && rulim && ch >= '0' && ch <= '9');
 544
 545         if (result < llim || result > ulim)
 546                 return NULL;
 547
 548         *dest = result;
 549         return buf;
 550 }
 551
 552 static const u_char *
 553 find_string(const u_char *bp, int *tgt, const char * const *n1,
 554                 const char * const *n2, int c)
 555 {
 556         int i;
 557         unsigned int len;
 558
 559         /* check full name - then abbreviated ones */
 560         for (; n1 != NULL; n1 = n2, n2 = NULL) {
 561                 for (i = 0; i < c; i++, n1++) {
 562                         len = strlen(*n1);
 563                         if (strncasecmp(*n1, (const char *)bp, len) == 0) {
 564                                 *tgt = i;
 565                                 return bp + len;
 566                         }
 567                 }
 568         }
 569
 570         /* Nothing matched */
 571         return NULL;
 572 }