openbsd-compat/strptime.c

   1 /*      $OpenBSD: strptime.c,v 1.12 2008/06/26 05:42:05 ray Exp $ */
   2 /*      $NetBSD: strptime.c,v 1.12 1998/01/20 21:39:40 mycroft Exp $    */
   3
   4 /*-
   5  * Copyright (c) 1997, 1998 The NetBSD Foundation, Inc.
   6  * All rights reserved.
   7  *
   8  * This code was contributed to The NetBSD Foundation by Klaus Klein.
   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 /* OPENBSD ORIGINAL: lib/libc/time/strptime.c */
  33
  34 #include "includes.h"
  35
  36 #ifndef HAVE_STRPTIME
  37
  38 #define TM_YEAR_BASE 1900       /* from tzfile.h */
  39
  40 #include <ctype.h>
  41 #include <locale.h>
  42 #include <string.h>
  43 #include <time.h>
  44
  45 /* #define      _ctloc(x)               (_CurrentTimeLocale->x) */
  46
  47 /*
  48  * We do not implement alternate representations. However, we always
  49  * check whether a given modifier is allowed for a certain conversion.
  50  */
  51 #define _ALT_E                  0x01
  52 #define _ALT_O                  0x02
  53 #define _LEGAL_ALT(x)           { if (alt_format & ~(x)) return (0); }
  54
  55
  56 static  int _conv_num(const unsigned char **, int *, int, int);
  57 static  char *_strptime(const char *, const char *, struct tm *, int);
  58
  59
  60 char *
  61 strptime(const char *buf, const char *fmt, struct tm *tm)
  62 {
  63         return(_strptime(buf, fmt, tm, 1));
  64 }
  65
  66 static char *
  67 _strptime(const char *buf, const char *fmt, struct tm *tm, int initialize)
  68 {
  69         unsigned char c;
  70         const unsigned char *bp;
  71         size_t len;
  72         int alt_format, i;
  73         static int century, relyear;
  74
  75         if (initialize) {
  76                 century = TM_YEAR_BASE;
  77                 relyear = -1;
  78         }
  79
  80         bp = (unsigned char *)buf;
  81         while ((c = *fmt) != '\0') {
  82                 /* Clear `alternate' modifier prior to new conversion. */
  83                 alt_format = 0;
  84
  85                 /* Eat up white-space. */
  86                 if (isspace(c)) {
  87                         while (isspace(*bp))
  88                                 bp++;
  89
  90                         fmt++;
  91                         continue;
  92                 }
  93
  94                 if ((c = *fmt++) != '%')
  95                         goto literal;
  96
  97
  98 again:          switch (c = *fmt++) {
  99                 case '%':       /* "%%" is converted to "%". */
 100 literal:
 101                 if (c != *bp++)
 102                         return (NULL);
 103
 104                 break;
 105
 106                 /*
 107                  * "Alternative" modifiers. Just set the appropriate flag
 108                  * and start over again.
 109                  */
 110                 case 'E':       /* "%E?" alternative conversion modifier. */
 111                         _LEGAL_ALT(0);
 112                         alt_format |= _ALT_E;
 113                         goto again;
 114
 115                 case 'O':       /* "%O?" alternative conversion modifier. */
 116                         _LEGAL_ALT(0);
 117                         alt_format |= _ALT_O;
 118                         goto again;
 119
 120                 /*
 121                  * "Complex" conversion rules, implemented through recursion.
 122                  */
 123 #if 0
 124                 case 'c':       /* Date and time, using the locale's format. */
 125                         _LEGAL_ALT(_ALT_E);
 126                         if (!(bp = _strptime(bp, _ctloc(d_t_fmt), tm, 0)))
 127                                 return (NULL);
 128                         break;
 129 #endif
 130                 case 'D':       /* The date as "%m/%d/%y". */
 131                         _LEGAL_ALT(0);
 132                         if (!(bp = _strptime(bp, "%m/%d/%y", tm, 0)))
 133                                 return (NULL);
 134                         break;
 135
 136                 case 'R':       /* The time as "%H:%M". */
 137                         _LEGAL_ALT(0);
 138                         if (!(bp = _strptime(bp, "%H:%M", tm, 0)))
 139                                 return (NULL);
 140                         break;
 141
 142                 case 'r':       /* The time as "%I:%M:%S %p". */
 143                         _LEGAL_ALT(0);
 144                         if (!(bp = _strptime(bp, "%I:%M:%S %p", tm, 0)))
 145                                 return (NULL);
 146                         break;
 147
 148                 case 'T':       /* The time as "%H:%M:%S". */
 149                         _LEGAL_ALT(0);
 150                         if (!(bp = _strptime(bp, "%H:%M:%S", tm, 0)))
 151                                 return (NULL);
 152                         break;
 153 #if 0
 154                 case 'X':       /* The time, using the locale's format. */
 155                         _LEGAL_ALT(_ALT_E);
 156                         if (!(bp = _strptime(bp, _ctloc(t_fmt), tm, 0)))
 157                                 return (NULL);
 158                         break;
 159
 160                 case 'x':       /* The date, using the locale's format. */
 161                         _LEGAL_ALT(_ALT_E);
 162                         if (!(bp = _strptime(bp, _ctloc(d_fmt), tm, 0)))
 163                                 return (NULL);
 164                         break;
 165 #endif
 166                 /*
 167                  * "Elementary" conversion rules.
 168                  */
 169 #if 0
 170                 case 'A':       /* The day of week, using the locale's form. */
 171                 case 'a':
 172                         _LEGAL_ALT(0);
 173                         for (i = 0; i < 7; i++) {
 174                                 /* Full name. */
 175                                 len = strlen(_ctloc(day[i]));
 176                                 if (strncasecmp(_ctloc(day[i]), bp, len) == 0)
 177                                         break;
 178
 179                                 /* Abbreviated name. */
 180                                 len = strlen(_ctloc(abday[i]));
 181                                 if (strncasecmp(_ctloc(abday[i]), bp, len) == 0)
 182                                         break;
 183                         }
 184
 185                         /* Nothing matched. */
 186                         if (i == 7)
 187                                 return (NULL);
 188
 189                         tm->tm_wday = i;
 190                         bp += len;
 191                         break;
 192
 193                 case 'B':       /* The month, using the locale's form. */
 194                 case 'b':
 195                 case 'h':
 196                         _LEGAL_ALT(0);
 197                         for (i = 0; i < 12; i++) {
 198                                 /* Full name. */
 199                                 len = strlen(_ctloc(mon[i]));
 200                                 if (strncasecmp(_ctloc(mon[i]), bp, len) == 0)
 201                                         break;
 202
 203                                 /* Abbreviated name. */
 204                                 len = strlen(_ctloc(abmon[i]));
 205                                 if (strncasecmp(_ctloc(abmon[i]), bp, len) == 0)
 206                                         break;
 207                         }
 208
 209                         /* Nothing matched. */
 210                         if (i == 12)
 211                                 return (NULL);
 212
 213                         tm->tm_mon = i;
 214                         bp += len;
 215                         break;
 216 #endif
 217
 218                 case 'C':       /* The century number. */
 219                         _LEGAL_ALT(_ALT_E);
 220                         if (!(_conv_num(&bp, &i, 0, 99)))
 221                                 return (NULL);
 222
 223                         century = i * 100;
 224                         break;
 225
 226                 case 'd':       /* The day of month. */
 227                 case 'e':
 228                         _LEGAL_ALT(_ALT_O);
 229                         if (!(_conv_num(&bp, &tm->tm_mday, 1, 31)))
 230                                 return (NULL);
 231                         break;
 232
 233                 case 'k':       /* The hour (24-hour clock representation). */
 234                         _LEGAL_ALT(0);
 235                         /* FALLTHROUGH */
 236                 case 'H':
 237                         _LEGAL_ALT(_ALT_O);
 238                         if (!(_conv_num(&bp, &tm->tm_hour, 0, 23)))
 239                                 return (NULL);
 240                         break;
 241
 242                 case 'l':       /* The hour (12-hour clock representation). */
 243                         _LEGAL_ALT(0);
 244                         /* FALLTHROUGH */
 245                 case 'I':
 246                         _LEGAL_ALT(_ALT_O);
 247                         if (!(_conv_num(&bp, &tm->tm_hour, 1, 12)))
 248                                 return (NULL);
 249                         break;
 250
 251                 case 'j':       /* The day of year. */
 252                         _LEGAL_ALT(0);
 253                         if (!(_conv_num(&bp, &tm->tm_yday, 1, 366)))
 254                                 return (NULL);
 255                         tm->tm_yday--;
 256                         break;
 257
 258                 case 'M':       /* The minute. */
 259                         _LEGAL_ALT(_ALT_O);
 260                         if (!(_conv_num(&bp, &tm->tm_min, 0, 59)))
 261                                 return (NULL);
 262                         break;
 263
 264                 case 'm':       /* The month. */
 265                         _LEGAL_ALT(_ALT_O);
 266                         if (!(_conv_num(&bp, &tm->tm_mon, 1, 12)))
 267                                 return (NULL);
 268                         tm->tm_mon--;
 269                         break;
 270
 271 #if 0
 272                 case 'p':       /* The locale's equivalent of AM/PM. */
 273                         _LEGAL_ALT(0);
 274                         /* AM? */
 275                         len = strlen(_ctloc(am_pm[0]));
 276                         if (strncasecmp(_ctloc(am_pm[0]), bp, len) == 0) {
 277                                 if (tm->tm_hour > 12)   /* i.e., 13:00 AM ?! */
 278                                         return (NULL);
 279                                 else if (tm->tm_hour == 12)
 280                                         tm->tm_hour = 0;
 281
 282                                 bp += len;
 283                                 break;
 284                         }
 285                         /* PM? */
 286                         len = strlen(_ctloc(am_pm[1]));
 287                         if (strncasecmp(_ctloc(am_pm[1]), bp, len) == 0) {
 288                                 if (tm->tm_hour > 12)   /* i.e., 13:00 PM ?! */
 289                                         return (NULL);
 290                                 else if (tm->tm_hour < 12)
 291                                         tm->tm_hour += 12;
 292
 293                                 bp += len;
 294                                 break;
 295                         }
 296
 297                         /* Nothing matched. */
 298                         return (NULL);
 299 #endif
 300                 case 'S':       /* The seconds. */
 301                         _LEGAL_ALT(_ALT_O);
 302                         if (!(_conv_num(&bp, &tm->tm_sec, 0, 61)))
 303                                 return (NULL);
 304                         break;
 305
 306                 case 'U':       /* The week of year, beginning on sunday. */
 307                 case 'W':       /* The week of year, beginning on monday. */
 308                         _LEGAL_ALT(_ALT_O);
 309                         /*
 310                          * XXX This is bogus, as we can not assume any valid
 311                          * information present in the tm structure at this
 312                          * point to calculate a real value, so just check the
 313                          * range for now.
 314                          */
 315                          if (!(_conv_num(&bp, &i, 0, 53)))
 316                                 return (NULL);
 317                          break;
 318
 319                 case 'w':       /* The day of week, beginning on sunday. */
 320                         _LEGAL_ALT(_ALT_O);
 321                         if (!(_conv_num(&bp, &tm->tm_wday, 0, 6)))
 322                                 return (NULL);
 323                         break;
 324
 325                 case 'Y':       /* The year. */
 326                         _LEGAL_ALT(_ALT_E);
 327                         if (!(_conv_num(&bp, &i, 0, 9999)))
 328                                 return (NULL);
 329
 330                         relyear = -1;
 331                         tm->tm_year = i - TM_YEAR_BASE;
 332                         break;
 333
 334                 case 'y':       /* The year within the century (2 digits). */
 335                         _LEGAL_ALT(_ALT_E | _ALT_O);
 336                         if (!(_conv_num(&bp, &relyear, 0, 99)))
 337                                 return (NULL);
 338                         break;
 339
 340                 /*
 341                  * Miscellaneous conversions.
 342                  */
 343                 case 'n':       /* Any kind of white-space. */
 344                 case 't':
 345                         _LEGAL_ALT(0);
 346                         while (isspace(*bp))
 347                                 bp++;
 348                         break;
 349
 350
 351                 default:        /* Unknown/unsupported conversion. */
 352                         return (NULL);
 353                 }
 354
 355
 356         }
 357
 358         /*
 359          * We need to evaluate the two digit year spec (%y)
 360          * last as we can get a century spec (%C) at any time.
 361          */
 362         if (relyear != -1) {
 363                 if (century == TM_YEAR_BASE) {
 364                         if (relyear <= 68)
 365                                 tm->tm_year = relyear + 2000 - TM_YEAR_BASE;
 366                         else
 367                                 tm->tm_year = relyear + 1900 - TM_YEAR_BASE;
 368                 } else {
 369                         tm->tm_year = relyear + century - TM_YEAR_BASE;
 370                 }
 371         }
 372
 373         return ((char *)bp);
 374 }
 375
 376
 377 static int
 378 _conv_num(const unsigned char **buf, int *dest, int llim, int ulim)
 379 {
 380         int result = 0;
 381         int rulim = ulim;
 382
 383         if (**buf < '0' || **buf > '9')
 384                 return (0);
 385
 386         /* we use rulim to break out of the loop when we run out of digits */
 387         do {
 388                 result *= 10;
 389                 result += *(*buf)++ - '0';
 390                 rulim /= 10;
 391         } while ((result * 10 <= ulim) && rulim && **buf >= '0' && **buf <= '9');
 392
 393         if (result < llim || result > ulim)
 394                 return (0);
 395
 396         *dest = result;
 397         return (1);
 398 }
 399
 400 #endif /* HAVE_STRPTIME */
 401