stdtime/FreeBSD/strptime.c

   1 /*-
   2  * Copyright (c) 2014 Gary Mills
   3  * Copyright 2011, Nexenta Systems, Inc.  All rights reserved.
   4  * Copyright (c) 1994 Powerdog Industries.  All rights reserved.
   5  *
   6  * Copyright (c) 2011 The FreeBSD Foundation
   7  * All rights reserved.
   8  * Portions of this software were developed by David Chisnall
   9  * under sponsorship from the FreeBSD Foundation.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer
  18  *    in the documentation and/or other materials provided with the
  19  *    distribution.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY POWERDOG INDUSTRIES ``AS IS'' AND ANY
  22  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  24  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE POWERDOG INDUSTRIES BE
  25  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  26  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  27  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  28  * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  29  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
  30  * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
  31  * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  32  *
  33  * The views and conclusions contained in the software and documentation
  34  * are those of the authors and should not be interpreted as representing
  35  * official policies, either expressed or implied, of Powerdog Industries.
  36  */
  37
  38 #include <sys/cdefs.h>
  39 #ifndef lint
  40 #ifndef NOID
  41 static char copyright[] __unused =
  42 "@(#) Copyright (c) 1994 Powerdog Industries.  All rights reserved.";
  43 static char sccsid[] __unused = "@(#)strptime.c 0.1 (Powerdog) 94/03/27";
  44 #endif /* !defined NOID */
  45 #endif /* not lint */
  46 __FBSDID("$FreeBSD$");
  47
  48 #include "xlocale_private.h"
  49
  50 #include "namespace.h"
  51 #include <time.h>
  52 #include <ctype.h>
  53 #include <errno.h>
  54 #include <stdio.h>
  55 #include <stdlib.h>
  56 #include <string.h>
  57 #include <pthread.h>
  58 #include "un-namespace.h"
  59 #include "libc_private.h"
  60 #include "timelocal.h"
  61 #include "tzfile.h"
  62
  63 time_t _mktime(struct tm *, const char *);
  64
  65 #define asizeof(a)      (sizeof(a) / sizeof((a)[0]))
  66
  67 enum {CONVERT_NONE, CONVERT_GMT, CONVERT_ZONE};
  68 enum week_kind { WEEK_U = 'U', WEEK_V = 'V', WEEK_W = 'W'};
  69
  70 #define _strptime(b,f,t,c,l)    _strptime0(b,f,t,c,l,FLAG_NONE,0,WEEK_U)
  71
  72 #define FLAG_NONE       0x01
  73 #define FLAG_YEAR       0x02
  74 #define FLAG_MONTH      0x04
  75 #define FLAG_YDAY       0x08
  76 #define FLAG_MDAY       0x10
  77 #define FLAG_WDAY       0x20
  78 #define FLAG_WEEK       0x40
  79 #define FLAG_CENTURY 0x100
  80 #define FLAG_YEAR_IN_CENTURY 0x200
  81
  82 /*
  83  * Calculate the week day of the first day of a year. Valid for
  84  * the Gregorian calendar, which began Sept 14, 1752 in the UK
  85  * and its colonies. Ref:
  86  * http://en.wikipedia.org/wiki/Determination_of_the_day_of_the_week
  87  */
  88
  89 static int
  90 first_wday_of(int year)
  91 {
  92         return (((2 * (3 - (year / 100) % 4)) + (year % 100) +
  93                 ((year % 100) / 4) + (isleap(year) ? 6 : 0) + 1) % 7);
  94 }
  95
  96 static char *
  97 _strptime0(const char *buf, const char *fmt, struct tm *tm, int *convp, locale_t locale, int flags, int week_number, enum week_kind week_kind)
  98 {
  99         char    c;
 100         const char *ptr;
 101         int wday_offset;
 102         int     i, len;
 103         int Ealternative, Oalternative;
 104         const struct lc_time_T *tptr = __get_current_time_locale(locale);
 105         static int start_of_month[2][13] = {
 106                 {0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365},
 107                 {0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366}
 108         };
 109
 110         ptr = fmt;
 111         while (*ptr != 0) {
 112                 c = *ptr++;
 113
 114                 if (c != '%') {
 115                         if (isspace_l((unsigned char)c, locale))
 116                                 while (*buf != 0 &&
 117                                        isspace_l((unsigned char)*buf, locale))
 118                                         buf++;
 119                         else if (c != *buf++)
 120                                 return (NULL);
 121                         continue;
 122                 }
 123
 124                 Ealternative = 0;
 125                 Oalternative = 0;
 126 label:
 127                 c = *ptr++;
 128                 switch (c) {
 129                 case '%':
 130                         if (*buf++ != '%')
 131                                 return (NULL);
 132                         break;
 133
 134                 case '+':
 135                         buf = _strptime(buf, tptr->date_fmt, tm, convp, locale);
 136                         if (buf == NULL)
 137                                 return (NULL);
 138                         flags |= FLAG_WDAY | FLAG_MONTH | FLAG_MDAY | FLAG_YEAR;
 139                         break;
 140
 141                 case 'C':
 142                         if (!isdigit_l((unsigned char)*buf, locale))
 143                                 return (NULL);
 144
 145                         /* XXX This will break for 3-digit centuries. */
 146                         len = 2;
 147                         for (i = 0; len && *buf != 0 &&
 148                              isdigit_l((unsigned char)*buf, locale); buf++) {
 149                                 i *= 10;
 150                                 i += *buf - '0';
 151                                 len--;
 152                         }
 153                         if (i < 19)
 154                                 return (NULL);
 155
 156                         if (flags & FLAG_YEAR_IN_CENTURY) {
 157                                 tm->tm_year = i * 100 + (tm->tm_year % 100) - TM_YEAR_BASE;
 158                                 flags &= ~FLAG_YEAR_IN_CENTURY;
 159                         } else {
 160                                 tm->tm_year = i * 100 - TM_YEAR_BASE;
 161                                 flags |= FLAG_YEAR;
 162                                 flags |= FLAG_CENTURY;
 163                         }
 164
 165                         break;
 166
 167                 case 'c':
 168                         buf = _strptime(buf, tptr->c_fmt, tm, convp, locale);
 169                         if (buf == NULL)
 170                                 return (NULL);
 171                         flags |= FLAG_WDAY | FLAG_MONTH | FLAG_MDAY | FLAG_YEAR;
 172                         flags &= ~(FLAG_CENTURY | FLAG_YEAR_IN_CENTURY);
 173                         break;
 174
 175                 case 'D':
 176                         buf = _strptime(buf, "%m/%d/%y", tm, convp, locale);
 177                         if (buf == NULL)
 178                                 return (NULL);
 179                         flags |= FLAG_MONTH | FLAG_MDAY | FLAG_YEAR;
 180                         flags &= ~(FLAG_CENTURY | FLAG_YEAR_IN_CENTURY);
 181                         break;
 182
 183                 case 'E':
 184                         if (Ealternative || Oalternative)
 185                                 break;
 186                         Ealternative++;
 187                         if (*ptr == '%') return (NULL);
 188                         goto label;
 189
 190                 case 'O':
 191                         if (Ealternative || Oalternative)
 192                                 break;
 193                         Oalternative++;
 194                         if (*ptr == '%') return (NULL);
 195                         goto label;
 196
 197                 case 'F':
 198                         buf = _strptime(buf, "%Y-%m-%d", tm, convp, locale);
 199                         if (buf == NULL)
 200                                 return (NULL);
 201                         flags |= FLAG_MONTH | FLAG_MDAY | FLAG_YEAR;
 202                         flags &= ~(FLAG_CENTURY | FLAG_YEAR_IN_CENTURY);
 203                         break;
 204
 205                 case 'R':
 206                         buf = _strptime(buf, "%H:%M", tm, convp, locale);
 207                         if (buf == NULL)
 208                                 return (NULL);
 209                         break;
 210
 211                 case 'r':
 212                         buf = _strptime(buf, tptr->ampm_fmt, tm, convp, locale);
 213                         if (buf == NULL)
 214                                 return (NULL);
 215                         break;
 216
 217                 case 'T':
 218                         buf = _strptime(buf, "%H:%M:%S", tm, convp, locale);
 219                         if (buf == NULL)
 220                                 return (NULL);
 221                         break;
 222
 223                 case 'X':
 224                         buf = _strptime(buf, tptr->X_fmt, tm, convp, locale);
 225                         if (buf == NULL)
 226                                 return (NULL);
 227                         break;
 228
 229                 case 'x':
 230                         buf = _strptime(buf, tptr->x_fmt, tm, convp, locale);
 231                         if (buf == NULL)
 232                                 return (NULL);
 233                         flags |= FLAG_MONTH | FLAG_MDAY | FLAG_YEAR;
 234                         flags &= ~(FLAG_CENTURY | FLAG_YEAR_IN_CENTURY);
 235                         break;
 236
 237                 case 'j':
 238                         if (!isdigit_l((unsigned char)*buf, locale))
 239                                 return (NULL);
 240
 241                         len = 3;
 242                         for (i = 0; len && *buf != 0 &&
 243                              isdigit_l((unsigned char)*buf, locale); buf++){
 244                                 i *= 10;
 245                                 i += *buf - '0';
 246                                 len--;
 247                         }
 248                         if (i < 1 || i > 366)
 249                                 return (NULL);
 250
 251                         tm->tm_yday = i - 1;
 252                         flags |= FLAG_YDAY;
 253
 254                         break;
 255
 256                 case 'M':
 257                 case 'S':
 258                         if (*buf == 0 ||
 259                                 isspace_l((unsigned char)*buf, locale))
 260                                 break;
 261
 262                         if (!isdigit_l((unsigned char)*buf, locale))
 263                                 return (NULL);
 264
 265                         len = 2;
 266                         for (i = 0; len && *buf != 0 &&
 267                                 isdigit_l((unsigned char)*buf, locale); buf++){
 268                                 i *= 10;
 269                                 i += *buf - '0';
 270                                 len--;
 271                         }
 272
 273                         if (c == 'M') {
 274                                 if (i > 59)
 275                                         return (NULL);
 276                                 tm->tm_min = i;
 277                         } else {
 278                                 if (i > 60)
 279                                         return (NULL);
 280                                 tm->tm_sec = i;
 281                         }
 282
 283                         break;
 284
 285                 case 'H':
 286                 case 'I':
 287                 case 'k':
 288                 case 'l':
 289                         /*
 290                          * Of these, %l is the only specifier explicitly
 291                          * documented as not being zero-padded.  However,
 292                          * there is no harm in allowing zero-padding.
 293                          *
 294                          * XXX The %l specifier may gobble one too many
 295                          * digits if used incorrectly.
 296                          */
 297                         if (!isdigit_l((unsigned char)*buf, locale))
 298                                 return (NULL);
 299
 300                         len = 2;
 301                         for (i = 0; len && *buf != 0 &&
 302                              isdigit_l((unsigned char)*buf, locale); buf++) {
 303                                 i *= 10;
 304                                 i += *buf - '0';
 305                                 len--;
 306                         }
 307                         if (c == 'H' || c == 'k') {
 308                                 if (i > 23)
 309                                         return (NULL);
 310                         } else if (i > 12)
 311                                 return (NULL);
 312
 313                         tm->tm_hour = i;
 314
 315                         break;
 316
 317                 case 'p':
 318                         /*
 319                          * XXX This is bogus if parsed before hour-related
 320                          * specifiers.
 321                          */
 322                         if (tm->tm_hour > 12)
 323                                 return (NULL);
 324
 325                         len = strlen(tptr->am);
 326                         if (strncasecmp_l(buf, tptr->am, len, locale) == 0) {
 327                                 if (tm->tm_hour == 12)
 328                                         tm->tm_hour = 0;
 329                                 buf += len;
 330                                 break;
 331                         }
 332
 333                         len = strlen(tptr->pm);
 334                         if (strncasecmp_l(buf, tptr->pm, len, locale) == 0) {
 335                                 if (tm->tm_hour != 12)
 336                                         tm->tm_hour += 12;
 337                                 buf += len;
 338                                 break;
 339                         }
 340
 341                         return (NULL);
 342
 343                 case 'A':
 344                 case 'a':
 345                         for (i = 0; i < asizeof(tptr->weekday); i++) {
 346                                 len = strlen(tptr->weekday[i]);
 347                                 if (strncasecmp_l(buf, tptr->weekday[i],
 348                                                 len, locale) == 0)
 349                                         break;
 350                                 len = strlen(tptr->wday[i]);
 351                                 if (strncasecmp_l(buf, tptr->wday[i],
 352                                                 len, locale) == 0)
 353                                         break;
 354                         }
 355                         if (i == asizeof(tptr->weekday))
 356                                 return (NULL);
 357
 358                         buf += len;
 359                         tm->tm_wday = i;
 360                         flags |= FLAG_WDAY;
 361                         break;
 362
 363                 case 'U':       /* Sunday week */
 364                 case 'V':       /* ISO 8601 week */
 365                 case 'W':       /* Monday week */
 366                         if (!isdigit_l((unsigned char)*buf, locale))
 367                                 return (NULL);
 368
 369                         len = 2;
 370                         for (i = 0; len && *buf != 0 &&
 371                              isdigit_l((unsigned char)*buf, locale); buf++) {
 372                                 i *= 10;
 373                                 i += *buf - '0';
 374                                 len--;
 375                         }
 376                         if (i > 53)
 377                                 return (NULL);
 378                         if (c == WEEK_V && i < 1)
 379                                 return (NULL);
 380
 381                         week_number = i;
 382                         week_kind = c;
 383                         flags |= FLAG_WEEK;
 384
 385                         break;
 386
 387                 case 'u':       /* [1,7] */
 388                 case 'w':       /* [0,6] */
 389                         if (!isdigit_l((unsigned char)*buf, locale))
 390                                 return (NULL);
 391
 392                         i = *buf - '0';
 393                         if (i < 0 || i > 7 || (c == 'u' && i < 1) ||
 394                             (c == 'w' && i > 6))
 395                                 return (NULL);
 396
 397                         tm->tm_wday = i % 7;
 398                         flags |= FLAG_WDAY;
 399                         buf++;
 400
 401                         break;
 402
 403                 case 'e':
 404                         /*
 405                          * With %e format, our strftime(3) adds a blank space
 406                          * before single digits.
 407                          */
 408                         if (*buf != 0 &&
 409                             isspace_l((unsigned char)*buf, locale))
 410                                buf++;
 411                         /* FALLTHROUGH */
 412                 case 'd':
 413                         /*
 414                          * The %e specifier was once explicitly documented as
 415                          * not being zero-padded but was later changed to
 416                          * equivalent to %d.  There is no harm in allowing
 417                          * such padding.
 418                          *
 419                          * XXX The %e specifier may gobble one too many
 420                          * digits if used incorrectly.
 421                          */
 422                         /* Leading space is ok if date is single digit */
 423                         len = 2;
 424                         if (isspace_l((unsigned char)buf[0], locale) &&
 425                                 isdigit_l((unsigned char)buf[1], locale) &&
 426                                 !isdigit_l((unsigned char)buf[2], locale)) {
 427                                 len = 1;
 428                                 buf++;
 429                         }
 430                         if (!isdigit_l((unsigned char)*buf, locale))
 431                                 return (NULL);
 432
 433                         for (i = 0; len && *buf != 0 &&
 434                              isdigit_l((unsigned char)*buf, locale); buf++) {
 435                                 i *= 10;
 436                                 i += *buf - '0';
 437                                 len--;
 438                         }
 439                         if (i > 31)
 440                                 return (NULL);
 441
 442                         tm->tm_mday = i;
 443                         flags |= FLAG_MDAY;
 444
 445                         break;
 446
 447                 case 'B':
 448                 case 'b':
 449                 case 'h':
 450                         for (i = 0; i < asizeof(tptr->month); i++) {
 451                                 if (Oalternative) {
 452                                         if (c == 'B') {
 453                                                 len = strlen(tptr->alt_month[i]);
 454                                                 if (strncasecmp_l(buf,
 455                                                                 tptr->alt_month[i],
 456                                                                 len, locale) == 0)
 457                                                         break;
 458                                         }
 459                                 } else {
 460                                         len = strlen(tptr->month[i]);
 461                                         if (strncasecmp_l(buf, tptr->month[i],
 462                                                         len, locale) == 0)
 463                                                 break;
 464                                 }
 465                         }
 466                         /*
 467                          * Try the abbreviated month name if the full name
 468                          * wasn't found and Oalternative was not requested.
 469                          */
 470                         if (i == asizeof(tptr->month) && !Oalternative) {
 471                                 for (i = 0; i < asizeof(tptr->month); i++) {
 472                                         len = strlen(tptr->mon[i]);
 473                                         if (strncasecmp_l(buf, tptr->mon[i],
 474                                                         len, locale) == 0)
 475                                                 break;
 476                                 }
 477                         }
 478                         if (i == asizeof(tptr->month))
 479                                 return (NULL);
 480
 481                         tm->tm_mon = i;
 482                         buf += len;
 483                         flags |= FLAG_MONTH;
 484
 485                         break;
 486
 487                 case 'm':
 488                         if (!isdigit_l((unsigned char)*buf, locale))
 489                                 return (NULL);
 490
 491                         len = 2;
 492                         for (i = 0; len && *buf != 0 &&
 493                              isdigit_l((unsigned char)*buf, locale); buf++) {
 494                                 i *= 10;
 495                                 i += *buf - '0';
 496                                 len--;
 497                         }
 498                         if (i < 1 || i > 12)
 499                                 return (NULL);
 500
 501                         tm->tm_mon = i - 1;
 502                         flags |= FLAG_MONTH;
 503
 504                         break;
 505
 506                 case 's':
 507                         {
 508                         char *cp;
 509                         int sverrno;
 510                         long n;
 511                         time_t t;
 512
 513                         sverrno = errno;
 514                         errno = 0;
 515                         n = strtol_l(buf, &cp, 10, locale);
 516                         if (errno == ERANGE || (long)(t = n) != n) {
 517                                 errno = sverrno;
 518                                 return (NULL);
 519                         }
 520                         errno = sverrno;
 521                         buf = cp;
 522                         if (gmtime_r(&t, tm) == NULL)
 523                                 return (NULL);
 524                         *convp = CONVERT_GMT;
 525                         flags |= FLAG_YDAY | FLAG_WDAY | FLAG_MONTH |
 526                             FLAG_MDAY | FLAG_YEAR;
 527                         flags &= ~(FLAG_CENTURY | FLAG_YEAR_IN_CENTURY);
 528                         }
 529                         break;
 530
 531                 case 'Y':
 532                 case 'y':
 533                         if (*buf == 0 ||
 534                             isspace_l((unsigned char)*buf, locale))
 535                                 break;
 536
 537                         if (!isdigit_l((unsigned char)*buf, locale))
 538                                 return (NULL);
 539
 540 #if __DARWIN_UNIX03
 541                         if (c == 'Y') {
 542                                 int savei = 0;
 543                                 const char *savebuf = buf;
 544                                 int64_t i64 = 0;
 545                                 int overflow = 0;
 546
 547                                 for (len = 0; *buf != 0 && isdigit_l((unsigned char)*buf, locale); buf++) {
 548                                         i64 *= 10;
 549                                         i64 += *buf - '0';
 550                                         if (++len <= 4) {
 551                                                 savei = i64;
 552                                                 savebuf = buf + 1;
 553                                         }
 554                                         if (i64 > INT_MAX) {
 555                                                 overflow++;
 556                                                 break;
 557                                         }
 558                                 }
 559                                 /*
 560                                  * Conformance requires %Y to be more then 4
 561                                  * digits.  However, there are several cases
 562                                  * where %Y is immediately followed by other
 563                                  * digits values.  So we do the conformance
 564                                  * case first (as many digits as possible),
 565                                  * and if we fail, we backup and try just 4
 566                                  * digits for %Y.
 567                                  */
 568                                 if (len > 4 && !overflow) {
 569                                         struct tm savetm = *tm;
 570                                         int saveconv = *convp;
 571                                         const char *saveptr = ptr;
 572                                         char *ret;
 573
 574                                         if (i64 < 1900)
 575                                                 return 0;
 576
 577                                         tm->tm_year = i64 - 1900;
 578
 579                                         if (*buf != 0 && isspace_l((unsigned char)*buf, locale))
 580                                                 while (*ptr != 0 && !isspace_l((unsigned char)*ptr, locale) && *ptr != '%')
 581                                                         ptr++;
 582                                         ret = _strptime0(buf, ptr, tm, convp, locale, flags, week_number, week_kind);
 583                                         if (ret) return ret;
 584                                         /* Failed, so try 4-digit year */
 585                                         *tm = savetm;
 586                                         *convp = saveconv;
 587                                         ptr = saveptr;
 588                                 }
 589                                 buf = savebuf;
 590                                 i = savei;
 591                         } else {
 592                                 len = 2;
 593 #else /* !__DARWIN_UNIX03 */
 594                                 len = (c == 'Y') ? 4 : 2;
 595 #endif /* __DARWIN_UNIX03 */
 596
 597                                 for (i = 0; len && *buf != 0 &&
 598                                          isdigit_l((unsigned char)*buf, locale); buf++) {
 599                                         i *= 10;
 600                                         i += *buf - '0';
 601                                         len--;
 602                                 }
 603 #if __DARWIN_UNIX03
 604                         }
 605 #endif /* __DARWIN_UNIX03 */
 606
 607                         if (i < 0)
 608                                 return (NULL);
 609
 610                         if (c == 'Y'){
 611                                 i -= TM_YEAR_BASE;
 612                         } else if (c == 'y' && flags & FLAG_CENTURY) {
 613                                 i = tm->tm_year + (i % 100);
 614                                 flags &= ~FLAG_CENTURY;
 615                         } else if (c == 'y'){
 616                                 if (i < 69) i += 100;
 617                                 flags |= FLAG_YEAR_IN_CENTURY;
 618                         }
 619
 620                         tm->tm_year = i;
 621                         flags |= FLAG_YEAR;
 622                         if (c == 'Y'){
 623                                 flags &= ~(FLAG_CENTURY | FLAG_YEAR_IN_CENTURY);
 624                         }
 625
 626                         break;
 627
 628                 case 'Z':
 629                         {
 630                                 const char *cp;
 631                                 size_t tzlen, len;
 632
 633                                 for (cp = buf; *cp &&
 634                                          isupper_l((unsigned char)*cp, locale); ++cp) {
 635                                         /*empty*/
 636                                 }
 637                                 len = cp - buf;
 638                                 if (len == 3 && strncmp(buf, "GMT", 3) == 0) {
 639                                         *convp = CONVERT_GMT;
 640                                         buf += len;
 641                                         break;
 642                                 }
 643
 644                                 tzset();
 645                                 tzlen = strlen(tzname[0]);
 646                                 if (len == tzlen && strncmp(buf, tzname[0], tzlen) == 0) {
 647                                         tm->tm_isdst = 0;
 648                                         buf += len;
 649                                         break;
 650                                 }
 651                                 tzlen = strlen(tzname[1]);
 652                                 if (len == tzlen && strncmp(buf, tzname[1], tzlen) == 0) {
 653                                         tm->tm_isdst = 1;
 654                                         buf += len;
 655                                         break;
 656                                 }
 657                                 return (NULL);
 658                         }
 659
 660                 case 'z':
 661                         {
 662                                 char sign;
 663                                 int hr, min;
 664                                 if ((buf[0] != '+' && buf[0] != '-')
 665                                         || !isdigit_l((unsigned char)buf[1], locale)
 666                                         || !isdigit_l((unsigned char)buf[2], locale)
 667                                         || !isdigit_l((unsigned char)buf[3], locale)
 668                                         || !isdigit_l((unsigned char)buf[4], locale))
 669                                         return 0;
 670                                 sscanf(buf, "%c%2d%2d", &sign, &hr, &min);
 671                                 *convp = CONVERT_ZONE;
 672                                 tm->tm_gmtoff = 60 * (60 * hr + min);
 673                                 if (sign == '-')
 674                                         tm->tm_gmtoff = -tm->tm_gmtoff;
 675                                 buf += 5;
 676                         }
 677                         break;
 678
 679                 case 'n':
 680                 case 't':
 681                         if (!isspace((unsigned char)*buf))
 682                                 return 0;
 683                         while (isspace_l((unsigned char)*buf, locale))
 684                                 buf++;
 685                         break;
 686
 687                 default:
 688                         return (NULL);
 689                 }
 690         }
 691
 692         if (!(flags & FLAG_YDAY) && (flags & FLAG_YEAR)) {
 693                 if ((flags & (FLAG_MONTH | FLAG_MDAY)) ==
 694                     (FLAG_MONTH | FLAG_MDAY)) {
 695                         tm->tm_yday = start_of_month[isleap(tm->tm_year +
 696                             TM_YEAR_BASE)][tm->tm_mon] + (tm->tm_mday - 1);
 697                         flags |= FLAG_YDAY;
 698                 } else if (flags & FLAG_WEEK){
 699                         int day_offset = week_kind == WEEK_U ? TM_SUNDAY : TM_MONDAY;
 700                         int fwo = first_wday_of(tm->tm_year + TM_YEAR_BASE);
 701
 702                         /* No incomplete week (week 0). */
 703                         if (week_number == 0 && fwo == day_offset)
 704                                 return (NULL);
 705
 706                         if (!(flags & FLAG_WDAY)) {
 707                                 /*
 708                                  * Set the date to the first Sunday (or Monday)
 709                                  * of the specified week of the year.
 710                                  */
 711                                 tm->tm_wday = day_offset;
 712                                 flags |= FLAG_WDAY;
 713                         }
 714
 715                         /*
 716                          * Start our yday at the first day of the relevant week type.
 717                          */
 718                         int tmpyday = (7 - fwo + day_offset) % 7;
 719
 720                         /*
 721                          * ISO Weeks start counting from the first week with at least
 722                          * four days.  If our first week had that, subtract off a week.
 723                          */
 724                         if (week_kind == WEEK_V && fwo > TM_MONDAY && fwo <= TM_THURSDAY) {
 725                                 tmpyday -= 7;
 726                         }
 727                         /* Advance the relevant number of weeks */
 728                         tmpyday += (week_number - 1) * 7;
 729                         /* And go to the right day of week */
 730                         tmpyday += (tm->tm_wday - day_offset + 7) % 7;
 731
 732                         /* Impossible yday for incomplete week (week 0). */
 733                         if (tmpyday < 0) {
 734                                 if (flags & FLAG_WDAY)
 735                                         return (NULL);
 736                                 tmpyday = 0;
 737                         }
 738                         tm->tm_yday = tmpyday;
 739                         flags |= FLAG_YDAY;
 740                 }
 741         }
 742
 743         if ((flags & (FLAG_YEAR | FLAG_YDAY)) == (FLAG_YEAR | FLAG_YDAY)) {
 744                 if (!(flags & FLAG_MONTH)) {
 745                         i = 0;
 746                         while (tm->tm_yday >=
 747                             start_of_month[isleap(tm->tm_year +
 748                             TM_YEAR_BASE)][i])
 749                                 i++;
 750                         if (i > 12) {
 751                                 i = 1;
 752                                 tm->tm_yday -=
 753                                     start_of_month[isleap(tm->tm_year +
 754                                     TM_YEAR_BASE)][12];
 755                                 tm->tm_year++;
 756                         }
 757                         tm->tm_mon = i - 1;
 758                         flags |= FLAG_MONTH;
 759                 }
 760                 if (!(flags & FLAG_MDAY)) {
 761                         tm->tm_mday = tm->tm_yday -
 762                             start_of_month[isleap(tm->tm_year + TM_YEAR_BASE)]
 763                             [tm->tm_mon] + 1;
 764                         flags |= FLAG_MDAY;
 765                 }
 766                 if (!(flags & FLAG_WDAY)) {
 767                         wday_offset = first_wday_of(tm->tm_year + TM_YEAR_BASE);
 768                         tm->tm_wday = (wday_offset + tm->tm_yday) % 7;
 769                         flags |= FLAG_WDAY;
 770                 }
 771         }
 772
 773         return ((char *)buf);
 774 }
 775
 776
 777 char *
 778 strptime(const char * __restrict buf, const char * __restrict fmt,
 779                  struct tm * __restrict tm)
 780 {
 781         return strptime_l(buf, fmt, tm, __current_locale());
 782 }
 783
 784 extern time_t timeoff(struct tm *, long);
 785
 786 char *
 787 strptime_l(const char * __restrict buf, const char * __restrict fmt,
 788     struct tm * __restrict tm, locale_t loc)
 789 {
 790         char *ret;
 791         int conv;
 792
 793         NORMALIZE_LOCALE(loc);
 794         conv = CONVERT_NONE;
 795         tm->tm_zone = NULL;
 796         ret = _strptime(buf, fmt, tm, &conv, loc);
 797         if (ret) {
 798                 time_t t;
 799
 800                 switch(conv) {
 801                 case CONVERT_GMT:
 802                         t = timegm(tm);
 803                         localtime_r(&t, tm);
 804                         break;
 805                 case CONVERT_ZONE:
 806                     {
 807                         long offset = tm->tm_gmtoff;
 808                         tm->tm_gmtoff = 0;
 809                         t = timeoff(tm, offset);
 810                         localtime_r(&t, tm);
 811                         break;
 812                     }
 813                 }
 814         }
 815
 816         return (ret);
 817 }