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