lib/libc/stdtime/strptime.c

   1 /*      $NetBSD: strptime.c,v 1.31 2008/11/04 21:08:33 christos Exp $   */
   2 /*      $DragonFly: src/lib/libc/stdtime/strptime.c,v 1.5 2005/12/04 23:25:40 swildner Exp $ */
   3
   4 /*-
   5  * Copyright (c) 1997, 1998, 2005, 2008 The NetBSD Foundation, Inc.
   6  * All rights reserved.
   7  *
   8  * This code was contributed to The NetBSD Foundation by Klaus Klein.
   9  * Heavily optimised by David Laight
  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 in the
  18  *    documentation and/or other materials provided with the distribution.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  22  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  23  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  24  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  26  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  30  * POSSIBILITY OF SUCH DAMAGE.
  31  */
  32
  33 #include <sys/localedef.h>
  34 #include <ctype.h>
  35 #include <locale.h>
  36 #include <string.h>
  37 #include <time.h>
  38 #include "private.h"
  39 #include "tzfile.h"
  40
  41 #define _ctloc(x)               (_CurrentTimeLocale->x)
  42
  43 /*
  44  * We do not implement alternate representations. However, we always
  45  * check whether a given modifier is allowed for a certain conversion.
  46  */
  47 #define ALT_E                   0x01
  48 #define ALT_O                   0x02
  49 #define LEGAL_ALT(x)            { if (alt_format & ~(x)) return NULL; }
  50
  51 static char gmt[] = { "GMT" };
  52 static char utc[] = { "UTC" };
  53
  54 static const u_char *conv_num(const unsigned char *, int *, uint, uint);
  55 static const u_char *find_string(const u_char *, int *, const char * const *,
  56         const char * const *, int);
  57
  58 char *
  59 strptime(const char * __restrict buf, const char * __restrict fmt,
  60          struct tm * __restrict tm)
  61 {
  62         unsigned char c;
  63         const unsigned char *bp;
  64         int alt_format, i, split_year = 0, neg, offs;
  65         const char *new_fmt;
  66
  67         bp = (const u_char *)buf;
  68
  69         while (bp != NULL && (c = *fmt++) != '\0') {
  70                 /* Clear `alternate' modifier prior to new conversion. */
  71                 alt_format = 0;
  72                 i = 0;
  73
  74                 /* Eat up white-space. */
  75                 if (isspace(c)) {
  76                         while (isspace(*bp))
  77                                 bp++;
  78                         continue;
  79                 }
  80
  81                 if (c != '%')
  82                         goto literal;
  83
  84
  85 again:          switch (c = *fmt++) {
  86                 case '%':       /* "%%" is converted to "%". */
  87 literal:
  88                         if (c != *bp++)
  89                                 return NULL;
  90                         LEGAL_ALT(0);
  91                         continue;
  92
  93                 /*
  94                  * "Alternative" modifiers. Just set the appropriate flag
  95                  * and start over again.
  96                  */
  97                 case 'E':       /* "%E?" alternative conversion modifier. */
  98                         LEGAL_ALT(0);
  99                         alt_format |= ALT_E;
 100                         goto again;
 101
 102                 case 'O':       /* "%O?" alternative conversion modifier. */
 103                         LEGAL_ALT(0);
 104                         alt_format |= ALT_O;
 105                         goto again;
 106
 107                 /*
 108                  * "Complex" conversion rules, implemented through recursion.
 109                  */
 110                 case 'c':       /* Date and time, using the locale's format. */
 111                         new_fmt = _ctloc(d_t_fmt);
 112                         goto recurse;
 113
 114                 case 'D':       /* The date as "%m/%d/%y". */
 115                         new_fmt = "%m/%d/%y";
 116                         LEGAL_ALT(0);
 117                         goto recurse;
 118
 119                 case 'F':       /* The date as "%Y-%m-%d". */
 120                         new_fmt = "%Y-%m-%d";
 121                         LEGAL_ALT(0);
 122                         goto recurse;
 123
 124                 case 'R':       /* The time as "%H:%M". */
 125                         new_fmt = "%H:%M";
 126                         LEGAL_ALT(0);
 127                         goto recurse;
 128
 129                 case 'r':       /* The time in 12-hour clock representation. */
 130                         new_fmt =_ctloc(t_fmt_ampm);
 131                         LEGAL_ALT(0);
 132                         goto recurse;
 133
 134                 case 'T':       /* The time as "%H:%M:%S". */
 135                         new_fmt = "%H:%M:%S";
 136                         LEGAL_ALT(0);
 137                         goto recurse;
 138
 139                 case 'X':       /* The time, using the locale's format. */
 140                         new_fmt =_ctloc(t_fmt);
 141                         goto recurse;
 142
 143                 case 'x':       /* The date, using the locale's format. */
 144                         new_fmt =_ctloc(d_fmt);
 145                     recurse:
 146                         bp = (const u_char *)strptime((const char *)bp,
 147                                                             new_fmt, tm);
 148                         LEGAL_ALT(ALT_E);
 149                         continue;
 150
 151                 /*
 152                  * "Elementary" conversion rules.
 153                  */
 154                 case 'A':       /* The day of week, using the locale's form. */
 155                 case 'a':
 156                         bp = find_string(bp, &tm->tm_wday, _ctloc(day),
 157                                         _ctloc(abday), 7);
 158                         LEGAL_ALT(0);
 159                         continue;
 160
 161                 case 'B':       /* The month, using the locale's form. */
 162                 case 'b':
 163                 case 'h':
 164                         bp = find_string(bp, &tm->tm_mon, _ctloc(mon),
 165                                         _ctloc(abmon), 12);
 166                         LEGAL_ALT(0);
 167                         continue;
 168
 169                 case 'C':       /* The century number. */
 170                         i = 20;
 171                         bp = conv_num(bp, &i, 0, 99);
 172
 173                         i = i * 100 - TM_YEAR_BASE;
 174                         if (split_year)
 175                                 i += tm->tm_year % 100;
 176                         split_year = 1;
 177                         tm->tm_year = i;
 178                         LEGAL_ALT(ALT_E);
 179                         continue;
 180
 181                 case 'd':       /* The day of month. */
 182                 case 'e':
 183                         bp = conv_num(bp, &tm->tm_mday, 1, 31);
 184                         LEGAL_ALT(ALT_O);
 185                         continue;
 186
 187                 case 'k':       /* The hour (24-hour clock representation). */
 188                         LEGAL_ALT(0);
 189                         /* FALLTHROUGH */
 190                 case 'H':
 191                         bp = conv_num(bp, &tm->tm_hour, 0, 23);
 192                         LEGAL_ALT(ALT_O);
 193                         continue;
 194
 195                 case 'l':       /* The hour (12-hour clock representation). */
 196                         LEGAL_ALT(0);
 197                         /* FALLTHROUGH */
 198                 case 'I':
 199                         bp = conv_num(bp, &tm->tm_hour, 1, 12);
 200                         if (tm->tm_hour == 12)
 201                                 tm->tm_hour = 0;
 202                         LEGAL_ALT(ALT_O);
 203                         continue;
 204
 205                 case 'j':       /* The day of year. */
 206                         i = 1;
 207                         bp = conv_num(bp, &i, 1, 366);
 208                         tm->tm_yday = i - 1;
 209                         LEGAL_ALT(0);
 210                         continue;
 211
 212                 case 'M':       /* The minute. */
 213                         bp = conv_num(bp, &tm->tm_min, 0, 59);
 214                         LEGAL_ALT(ALT_O);
 215                         continue;
 216
 217                 case 'm':       /* The month. */
 218                         i = 1;
 219                         bp = conv_num(bp, &i, 1, 12);
 220                         tm->tm_mon = i - 1;
 221                         LEGAL_ALT(ALT_O);
 222                         continue;
 223
 224                 case 'p':       /* The locale's equivalent of AM/PM. */
 225                         bp = find_string(bp, &i, _ctloc(am_pm), NULL, 2);
 226                         if (tm->tm_hour > 11)
 227                                 return NULL;
 228                         tm->tm_hour += i * 12;
 229                         LEGAL_ALT(0);
 230                         continue;
 231
 232                 case 'S':       /* The seconds. */
 233                         bp = conv_num(bp, &tm->tm_sec, 0, 61);
 234                         LEGAL_ALT(ALT_O);
 235                         continue;
 236
 237                 case 'U':       /* The week of year, beginning on sunday. */
 238                 case 'W':       /* The week of year, beginning on monday. */
 239                         /*
 240                          * XXX This is bogus, as we can not assume any valid
 241                          * information present in the tm structure at this
 242                          * point to calculate a real value, so just check the
 243                          * range for now.
 244                          */
 245                          bp = conv_num(bp, &i, 0, 53);
 246                          LEGAL_ALT(ALT_O);
 247                          continue;
 248
 249                 case 'w':       /* The day of week, beginning on sunday. */
 250                         bp = conv_num(bp, &tm->tm_wday, 0, 6);
 251                         LEGAL_ALT(ALT_O);
 252                         continue;
 253
 254                 case 'u':       /* The day of week, monday = 1. */
 255                         bp = conv_num(bp, &i, 1, 7);
 256                         tm->tm_wday = i % 7;
 257                         LEGAL_ALT(ALT_O);
 258                         continue;
 259
 260                 case 'g':       /* The year corresponding to the ISO week
 261                                  * number but without the century.
 262                                  */
 263                         bp = conv_num(bp, &i, 0, 99);
 264                         continue;
 265
 266                 case 'G':       /* The year corresponding to the ISO week
 267                                  * number with century.
 268                                  */
 269                         do
 270                                 bp++;
 271                         while (isdigit(*bp));
 272                         continue;
 273
 274                 case 'V':       /* The ISO 8601:1988 week number as decimal */
 275                         bp = conv_num(bp, &i, 0, 53);
 276                         continue;
 277
 278                 case 'Y':       /* The year. */
 279                         i = TM_YEAR_BASE;       /* just for data sanity... */
 280                         bp = conv_num(bp, &i, 0, 9999);
 281                         tm->tm_year = i - TM_YEAR_BASE;
 282                         LEGAL_ALT(ALT_E);
 283                         continue;
 284
 285                 case 'y':       /* The year within 100 years of the epoch. */
 286                         /* LEGAL_ALT(ALT_E | ALT_O); */
 287                         bp = conv_num(bp, &i, 0, 99);
 288
 289                         if (split_year)
 290                                 /* preserve century */
 291                                 i += (tm->tm_year / 100) * 100;
 292                         else {
 293                                 split_year = 1;
 294                                 if (i <= 68)
 295                                         i = i + 2000 - TM_YEAR_BASE;
 296                                 else
 297                                         i = i + 1900 - TM_YEAR_BASE;
 298                         }
 299                         tm->tm_year = i;
 300                         continue;
 301
 302                 case 'Z':
 303                         tzset();
 304                         if (strncmp((const char *)bp, gmt, 3) == 0) {
 305                                 tm->tm_isdst = 0;
 306 #ifdef TM_GMTOFF
 307                                 tm->TM_GMTOFF = 0;
 308 #endif
 309 #ifdef TM_ZONE
 310                                 tm->TM_ZONE = gmt;
 311 #endif
 312                                 bp += 3;
 313                         } else {
 314                                 const unsigned char *ep;
 315
 316                                 ep = find_string(bp, &i,
 317                                                  (const char * const *)tzname,
 318                                                   NULL, 2);
 319                                 if (ep != NULL) {
 320                                         tm->tm_isdst = i;
 321 #ifdef TM_GMTOFF
 322                                         tm->TM_GMTOFF = -(timezone);
 323 #endif
 324 #ifdef TM_ZONE
 325                                         tm->TM_ZONE = tzname[i];
 326 #endif
 327                                 }
 328                                 bp = ep;
 329                         }
 330                         continue;
 331
 332                 case 'z':
 333                         /*
 334                          * We recognize all ISO 8601 formats:
 335                          * Z    = Zulu time/UTC
 336                          * [+-]hhmm
 337                          * [+-]hh:mm
 338                          * [+-]hh
 339                          */
 340                         while (isspace(*bp))
 341                                 bp++;
 342
 343                         switch (*bp++) {
 344                         case 'Z':
 345                                 tm->tm_isdst = 0;
 346 #ifdef TM_GMTOFF
 347                                 tm->TM_GMTOFF = 0;
 348 #endif
 349 #ifdef TM_ZONE
 350                                 tm->TM_ZONE = utc;
 351 #endif
 352                                 continue;
 353                         case '+':
 354                                 neg = 0;
 355                                 break;
 356                         case '-':
 357                                 neg = 1;
 358                                 break;
 359                         default:
 360                                 return NULL;
 361                         }
 362                         offs = 0;
 363                         for (i = 0; i < 4; ) {
 364                                 if (isdigit(*bp)) {
 365                                         offs = offs * 10 + (*bp++ - '0');
 366                                         i++;
 367                                         continue;
 368                                 }
 369                                 if (i == 2 && *bp == ':') {
 370                                         bp++;
 371                                         continue;
 372                                 }
 373                                 break;
 374                         }
 375                         switch (i) {
 376                         case 2:
 377                                 offs *= 100;
 378                                 break;
 379                         case 4:
 380                                 i = offs % 100;
 381                                 if (i >= 60)
 382                                         return NULL;
 383                                 /* Convert minutes into decimal */
 384                                 offs = (offs / 100) * 100 + (i * 50) / 30;
 385                                 break;
 386                         default:
 387                                 return NULL;
 388                         }
 389                         if (neg)
 390                                 offs = -offs;
 391                         tm->tm_isdst = 0;       /* XXX */
 392 #ifdef TM_GMTOFF
 393                         tm->TM_GMTOFF = offs;
 394 #endif
 395 #ifdef TM_ZONE
 396                         tm->TM_ZONE = NULL;     /* XXX */
 397 #endif
 398                         continue;
 399
 400                 /*
 401                  * Miscellaneous conversions.
 402                  */
 403                 case 'n':       /* Any kind of white-space. */
 404                 case 't':
 405                         while (isspace(*bp))
 406                                 bp++;
 407                         LEGAL_ALT(0);
 408                         continue;
 409
 410
 411                 default:        /* Unknown/unsupported conversion. */
 412                         return NULL;
 413                 }
 414         }
 415
 416         return __DECONST(char *, bp);
 417 }
 418
 419
 420 static const u_char *
 421 conv_num(const unsigned char *buf, int *dest, uint llim, uint ulim)
 422 {
 423         uint result = 0;
 424         unsigned char ch;
 425
 426         /* The limit also determines the number of valid digits. */
 427         uint rulim = ulim;
 428
 429         ch = *buf;
 430         if (ch < '0' || ch > '9')
 431                 return NULL;
 432
 433         do {
 434                 result *= 10;
 435                 result += ch - '0';
 436                 rulim /= 10;
 437                 ch = *++buf;
 438         } while ((result * 10 <= ulim) && rulim && ch >= '0' && ch <= '9');
 439
 440         if (result < llim || result > ulim)
 441                 return NULL;
 442
 443         *dest = result;
 444         return buf;
 445 }
 446
 447 static const u_char *
 448 find_string(const u_char *bp, int *tgt, const char * const *n1,
 449                 const char * const *n2, int c)
 450 {
 451         int i;
 452         unsigned int len;
 453
 454         /* check full name - then abbreviated ones */
 455         for (; n1 != NULL; n1 = n2, n2 = NULL) {
 456                 for (i = 0; i < c; i++, n1++) {
 457                         len = strlen(*n1);
 458                         if (strncasecmp(*n1, (const char *)bp, len) == 0) {
 459                                 *tgt = i;
 460                                 return bp + len;
 461                         }
 462                 }
 463         }
 464
 465         /* Nothing matched */
 466         return NULL;
 467 }