helper/strptime.c

   1 /*      $OpenBSD: strptime.c,v 1.11 2005/08/08 08:05:38 espie 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  * 3. All advertising materials mentioning features or use of this software
  19  *    must display the following acknowledgement:
  20  *        This product includes software developed by the NetBSD
  21  *        Foundation, Inc. and its contributors.
  22  * 4. Neither the name of The NetBSD Foundation nor the names of its
  23  *    contributors may be used to endorse or promote products derived
  24  *    from this software without specific prior written permission.
  25  *
  26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  36  * POSSIBILITY OF SUCH DAMAGE.
  37  */
  38
  39 #include <ctype.h>
  40 #include <locale.h>
  41 #include <string.h>
  42 #include <time.h>
  43 #include "tzfile.h"
  44 #include "strptime.h"
  45 #include "string.h"
  46
  47 static const struct {
  48         const char *abday[7];
  49         const char *day[7];
  50         const char *abmon[12];
  51         const char *mon[12];
  52         const char *am_pm[2];
  53         const char *d_t_fmt;
  54         const char *d_fmt;
  55         const char *t_fmt;
  56         const char *t_fmt_ampm;
  57 } _DefaultTimeLocale = {
  58         {
  59                 "Sun","Mon","Tue","Wed","Thu","Fri","Sat",
  60         },
  61         {
  62                 "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday",
  63                 "Friday", "Saturday"
  64         },
  65         {
  66                 "Jan", "Feb", "Mar", "Apr", "May", "Jun",
  67                 "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
  68         },
  69         {
  70                 "January", "February", "March", "April", "May", "June", "July",
  71                 "August", "September", "October", "November", "December"
  72         },
  73         {
  74                 "AM", "PM"
  75         },
  76         "%a %b %d %H:%M:%S %Y",
  77         "%m/%d/%y",
  78         "%H:%M:%S",
  79         "%I:%M:%S %p"
  80 };
  81
  82 #define _ctloc(x) (_DefaultTimeLocale.x)
  83
  84 /*
  85  * We do not implement alternate representations. However, we always
  86  * check whether a given modifier is allowed for a certain conversion.
  87  */
  88 #define _ALT_E                  0x01
  89 #define _ALT_O                  0x02
  90 #define _LEGAL_ALT(x)           { if (alt_format & ~(x)) return (0); }
  91
  92
  93 static  int _conv_num(unsigned char **, int *, int, int);
  94 static  char *_strptime(const char *, const char *, struct tm *, int);
  95
  96
  97 char *
  98 strptime(const char *buf, const char *fmt, struct tm *tm)
  99 {
 100         return(_strptime(buf, fmt, tm, 1));
 101 }
 102
 103 static char *
 104 _strptime(const char *buf, const char *fmt, struct tm *tm, int initialize)
 105 {
 106         unsigned char c;
 107         unsigned char *bp;
 108         size_t len = 0;
 109         int alt_format, i;
 110         static int century, relyear;
 111
 112         if (initialize) {
 113                 century = TM_YEAR_BASE;
 114                 relyear = -1;
 115         }
 116
 117         bp = (unsigned char *)buf;
 118         while ((c = *fmt) != '\0') {
 119                 /* Clear `alternate' modifier prior to new conversion. */
 120                 alt_format = 0;
 121
 122                 /* Eat up white-space. */
 123                 if (isspace(c)) {
 124                         while (isspace(*bp))
 125                                 bp++;
 126
 127                         fmt++;
 128                         continue;
 129                 }
 130
 131                 if ((c = *fmt++) != '%')
 132                         goto literal;
 133
 134
 135 again:          switch (c = *fmt++) {
 136                 case '%':       /* "%%" is converted to "%". */
 137 literal:
 138                 if (c != *bp++)
 139                         return (NULL);
 140
 141                 break;
 142
 143                 /*
 144                  * "Alternative" modifiers. Just set the appropriate flag
 145                  * and start over again.
 146                  */
 147                 case 'E':       /* "%E?" alternative conversion modifier. */
 148                         _LEGAL_ALT(0);
 149                         alt_format |= _ALT_E;
 150                         goto again;
 151
 152                 case 'O':       /* "%O?" alternative conversion modifier. */
 153                         _LEGAL_ALT(0);
 154                         alt_format |= _ALT_O;
 155                         goto again;
 156
 157                 /*
 158                  * "Complex" conversion rules, implemented through recursion.
 159                  */
 160                 case 'c':       /* Date and time, using the locale's format. */
 161                         _LEGAL_ALT(_ALT_E);
 162                         if ((bp = _strptime(bp, _ctloc(d_t_fmt), tm, 0)) == 0)
 163                                 return (NULL);
 164                         break;
 165
 166                 case 'D':       /* The date as "%m/%d/%y". */
 167                         _LEGAL_ALT(0);
 168                         if ((bp = _strptime(bp, "%m/%d/%y", tm, 0)) == 0)
 169                                 return (NULL);
 170                         break;
 171
 172                 case 'R':       /* The time as "%H:%M". */
 173                         _LEGAL_ALT(0);
 174                         if ((bp = _strptime(bp, "%H:%M", tm, 0)) == 0)
 175                                 return (NULL);
 176                         break;
 177
 178                 case 'r':       /* The time as "%I:%M:%S %p". */
 179                         _LEGAL_ALT(0);
 180                         if ((bp = _strptime(bp, "%I:%M:%S %p", tm, 0)) == 0)
 181                                 return (NULL);
 182                         break;
 183
 184                 case 'T':       /* The time as "%H:%M:%S". */
 185                         _LEGAL_ALT(0);
 186                         if ((bp = _strptime(bp, "%H:%M:%S", tm, 0)) == 0)
 187                                 return (NULL);
 188                         break;
 189
 190                 case 'X':       /* The time, using the locale's format. */
 191                         _LEGAL_ALT(_ALT_E);
 192                         if ((bp = _strptime(bp, _ctloc(t_fmt), tm, 0)) == 0)
 193                                 return (NULL);
 194                         break;
 195
 196                 case 'x':       /* The date, using the locale's format. */
 197                         _LEGAL_ALT(_ALT_E);
 198                         if ((bp = _strptime(bp, _ctloc(d_fmt), tm, 0)) == 0)
 199                                 return (NULL);
 200                         break;
 201
 202                 /*
 203                  * "Elementary" conversion rules.
 204                  */
 205                 case 'A':       /* The day of week, using the locale's form. */
 206                 case 'a':
 207                         _LEGAL_ALT(0);
 208                         for (i = 0; i < 7; i++) {
 209                                 /* Full name. */
 210                                 len = strlen(_ctloc(day[i]));
 211                                 if (strncasecmp(_ctloc(day[i]), bp, len) == 0)
 212                                         break;
 213
 214                                 /* Abbreviated name. */
 215                                 len = strlen(_ctloc(abday[i]));
 216                                 if (strncasecmp(_ctloc(abday[i]), bp, len) == 0)
 217                                         break;
 218                         }
 219
 220                         /* Nothing matched. */
 221                         if (i == 7)
 222                                 return (NULL);
 223
 224                         tm->tm_wday = i;
 225                         bp += len;
 226                         break;
 227
 228                 case 'B':       /* The month, using the locale's form. */
 229                 case 'b':
 230                 case 'h':
 231                         _LEGAL_ALT(0);
 232                         for (i = 0; i < 12; i++) {
 233                                 /* Full name. */
 234                                 len = strlen(_ctloc(mon[i]));
 235                                 if (strncasecmp(_ctloc(mon[i]), bp, len) == 0)
 236                                         break;
 237
 238                                 /* Abbreviated name. */
 239                                 len = strlen(_ctloc(abmon[i]));
 240                                 if (strncasecmp(_ctloc(abmon[i]), bp, len) == 0)
 241                                         break;
 242                         }
 243
 244                         /* Nothing matched. */
 245                         if (i == 12)
 246                                 return (NULL);
 247
 248                         tm->tm_mon = i;
 249                         bp += len;
 250                         break;
 251
 252                 case 'C':       /* The century number. */
 253                         _LEGAL_ALT(_ALT_E);
 254                         if (!(_conv_num(&bp, &i, 0, 99)))
 255                                 return (NULL);
 256
 257                         century = i * 100;
 258                         break;
 259
 260                 case 'd':       /* The day of month. */
 261                 case 'e':
 262                         _LEGAL_ALT(_ALT_O);
 263                         if (!(_conv_num(&bp, &tm->tm_mday, 1, 31)))
 264                                 return (NULL);
 265                         break;
 266
 267                 case 'k':       /* The hour (24-hour clock representation). */
 268                         _LEGAL_ALT(0);
 269                         /* FALLTHROUGH */
 270                 case 'H':
 271                         _LEGAL_ALT(_ALT_O);
 272                         if (!(_conv_num(&bp, &tm->tm_hour, 0, 23)))
 273                                 return (NULL);
 274                         break;
 275
 276                 case 'l':       /* The hour (12-hour clock representation). */
 277                         _LEGAL_ALT(0);
 278                         /* FALLTHROUGH */
 279                 case 'I':
 280                         _LEGAL_ALT(_ALT_O);
 281                         if (!(_conv_num(&bp, &tm->tm_hour, 1, 12)))
 282                                 return (NULL);
 283                         break;
 284
 285                 case 'j':       /* The day of year. */
 286                         _LEGAL_ALT(0);
 287                         if (!(_conv_num(&bp, &tm->tm_yday, 1, 366)))
 288                                 return (NULL);
 289                         tm->tm_yday--;
 290                         break;
 291
 292                 case 'M':       /* The minute. */
 293                         _LEGAL_ALT(_ALT_O);
 294                         if (!(_conv_num(&bp, &tm->tm_min, 0, 59)))
 295                                 return (NULL);
 296                         break;
 297
 298                 case 'm':       /* The month. */
 299                         _LEGAL_ALT(_ALT_O);
 300                         if (!(_conv_num(&bp, &tm->tm_mon, 1, 12)))
 301                                 return (NULL);
 302                         tm->tm_mon--;
 303                         break;
 304
 305                 case 'p':       /* The locale's equivalent of AM/PM. */
 306                         _LEGAL_ALT(0);
 307                         /* AM? */
 308                         len = strlen(_ctloc(am_pm[0]));
 309                         if (strncasecmp(_ctloc(am_pm[0]), bp, len) == 0) {
 310                                 if (tm->tm_hour > 12)   /* i.e., 13:00 AM ?! */
 311                                         return (NULL);
 312                                 else if (tm->tm_hour == 12)
 313                                         tm->tm_hour = 0;
 314
 315                                 bp += len;
 316                                 break;
 317                         }
 318                         /* PM? */
 319                         len = strlen(_ctloc(am_pm[1]));
 320                         if (strncasecmp(_ctloc(am_pm[1]), bp, len) == 0) {
 321                                 if (tm->tm_hour > 12)   /* i.e., 13:00 PM ?! */
 322                                         return (NULL);
 323                                 else if (tm->tm_hour < 12)
 324                                         tm->tm_hour += 12;
 325
 326                                 bp += len;
 327                                 break;
 328                         }
 329
 330                         /* Nothing matched. */
 331                         return (NULL);
 332
 333                 case 'S':       /* The seconds. */
 334                         _LEGAL_ALT(_ALT_O);
 335                         if (!(_conv_num(&bp, &tm->tm_sec, 0, 61)))
 336                                 return (NULL);
 337                         break;
 338
 339                 case 'U':       /* The week of year, beginning on sunday. */
 340                 case 'W':       /* The week of year, beginning on monday. */
 341                         _LEGAL_ALT(_ALT_O);
 342                         /*
 343                          * XXX This is bogus, as we can not assume any valid
 344                          * information present in the tm structure at this
 345                          * point to calculate a real value, so just check the
 346                          * range for now.
 347                          */
 348                          if (!(_conv_num(&bp, &i, 0, 53)))
 349                                 return (NULL);
 350                          break;
 351
 352                 case 'w':       /* The day of week, beginning on sunday. */
 353                         _LEGAL_ALT(_ALT_O);
 354                         if (!(_conv_num(&bp, &tm->tm_wday, 0, 6)))
 355                                 return (NULL);
 356                         break;
 357
 358                 case 'Y':       /* The year. */
 359                         _LEGAL_ALT(_ALT_E);
 360                         if (!(_conv_num(&bp, &i, 0, 9999)))
 361                                 return (NULL);
 362
 363                         relyear = -1;
 364                         tm->tm_year = i - TM_YEAR_BASE;
 365                         break;
 366
 367                 case 'y':       /* The year within the century (2 digits). */
 368                         _LEGAL_ALT(_ALT_E | _ALT_O);
 369                         if (!(_conv_num(&bp, &relyear, 0, 99)))
 370                                 return (NULL);
 371                         break;
 372
 373                 /*
 374                  * Miscellaneous conversions.
 375                  */
 376                 case 'n':       /* Any kind of white-space. */
 377                 case 't':
 378                         _LEGAL_ALT(0);
 379                         while (isspace(*bp))
 380                                 bp++;
 381                         break;
 382
 383
 384                 default:        /* Unknown/unsupported conversion. */
 385                         return (NULL);
 386                 }
 387
 388
 389         }
 390
 391         /*
 392          * We need to evaluate the two digit year spec (%y)
 393          * last as we can get a century spec (%C) at any time.
 394          */
 395         if (relyear != -1) {
 396                 if (century == TM_YEAR_BASE) {
 397                         if (relyear <= 68)
 398                                 tm->tm_year = relyear + 2000 - TM_YEAR_BASE;
 399                         else
 400                                 tm->tm_year = relyear + 1900 - TM_YEAR_BASE;
 401                 } else {
 402                         tm->tm_year = relyear + century - TM_YEAR_BASE;
 403                 }
 404         }
 405
 406         return ((char *)bp);
 407 }
 408
 409
 410 static int
 411 _conv_num(unsigned char **buf, int *dest, int llim, int ulim)
 412 {
 413         int result = 0;
 414         int rulim = ulim;
 415
 416         if (**buf < '0' || **buf > '9')
 417                 return (0);
 418
 419         /* we use rulim to break out of the loop when we run out of digits */
 420         do {
 421                 result *= 10;
 422                 result += *(*buf)++ - '0';
 423                 rulim /= 10;
 424         } while ((result * 10 <= ulim) && rulim && **buf >= '0' && **buf <= '9');
 425
 426         if (result < llim || result > ulim)
 427                 return (0);
 428
 429         *dest = result;
 430         return (1);
 431 }