lib/libc/stdtime/strptime.c

   1 /*      $NetBSD: src/lib/libc/time/strptime.c,v 1.22 2000/12/20 20:56:34 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 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 <sys/localedef.h>
  40 #include <ctype.h>
  41 #include <locale.h>
  42 #include <string.h>
  43 #include <time.h>
  44 #include "private.h"
  45 #include "tzfile.h"
  46
  47 #define _ctloc(x)               (_CurrentTimeLocale->x)
  48
  49 /*
  50  * We do not implement alternate representations. However, we always
  51  * check whether a given modifier is allowed for a certain conversion.
  52  */
  53 #define ALT_E                   0x01
  54 #define ALT_O                   0x02
  55 #define LEGAL_ALT(x)            { if (alt_format & ~(x)) return (0); }
  56
  57 static  int conv_num(const unsigned char **, int *, int, int);
  58
  59 char *
  60 strptime(const char *buf, const char *fmt, struct tm *tm)
  61 {
  62         unsigned char c;
  63         const unsigned char *bp;
  64         size_t len = 0;
  65         int alt_format, i, split_year = 0;
  66
  67         bp = (const u_char *)buf;
  68
  69         while ((c = *fmt) != '\0') {
  70                 /* Clear `alternate' modifier prior to new conversion. */
  71                 alt_format = 0;
  72
  73                 /* Eat up white-space. */
  74                 if (isspace(c)) {
  75                         while (isspace(*bp))
  76                                 bp++;
  77
  78                         fmt++;
  79                         continue;
  80                 }
  81
  82                 if ((c = *fmt++) != '%')
  83                         goto literal;
  84
  85
  86 again:          switch (c = *fmt++) {
  87                 case '%':       /* "%%" is converted to "%". */
  88 literal:
  89                         if (c != *bp++)
  90                                 return (0);
  91                         break;
  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                         LEGAL_ALT(ALT_E);
 112                         if (!(bp = (const u_char *)strptime((const char *)bp,
 113                             _ctloc(d_t_fmt), tm)))
 114                                 return (0);
 115                         break;
 116
 117                 case 'D':       /* The date as "%m/%d/%y". */
 118                         LEGAL_ALT(0);
 119                         if (!(bp = (const u_char *) strptime((const char *)bp,
 120                             "%m/%d/%y", tm)))
 121                                 return (0);
 122                         break;
 123
 124                 case 'R':       /* The time as "%H:%M". */
 125                         LEGAL_ALT(0);
 126                         if (!(bp = (const u_char *)strptime((const char *)bp,
 127                             "%H:%M", tm)))
 128                                 return (0);
 129                         break;
 130
 131                 case 'r':       /* The time in 12-hour clock representation. */
 132                         LEGAL_ALT(0);
 133                         if (!(bp = (const u_char *)strptime((const char *)bp,
 134                             _ctloc(t_fmt_ampm), tm)))
 135                                 return (0);
 136                         break;
 137
 138                 case 'T':       /* The time as "%H:%M:%S". */
 139                         LEGAL_ALT(0);
 140                         if (!(bp = (const u_char *)strptime((const char *)bp,
 141                             "%H:%M:%S", tm)))
 142                                 return (0);
 143                         break;
 144
 145                 case 'X':       /* The time, using the locale's format. */
 146                         LEGAL_ALT(ALT_E);
 147                         if (!(bp = (const u_char *)strptime((const char *)bp,
 148                             _ctloc(t_fmt), tm)))
 149                                 return (0);
 150                         break;
 151
 152                 case 'x':       /* The date, using the locale's format. */
 153                         LEGAL_ALT(ALT_E);
 154                         if (!(bp = (const u_char *)strptime((const char *)bp,
 155                             _ctloc(d_fmt), tm)))
 156                                 return (0);
 157                         break;
 158
 159                 /*
 160                  * "Elementary" conversion rules.
 161                  */
 162                 case 'A':       /* The day of week, using the locale's form. */
 163                 case 'a':
 164                         LEGAL_ALT(0);
 165                         for (i = 0; i < 7; i++) {
 166                                 /* Full name. */
 167                                 len = strlen(_ctloc(day[i]));
 168                                 if (strncasecmp(_ctloc(day[i]),
 169                                     (const char *)bp, len) == 0)
 170                                         break;
 171
 172                                 /* Abbreviated name. */
 173                                 len = strlen(_ctloc(abday[i]));
 174                                 if (strncasecmp(_ctloc(abday[i]),
 175                                     (const char *)bp, len) == 0)
 176                                         break;
 177                         }
 178
 179                         /* Nothing matched. */
 180                         if (i == 7)
 181                                 return (0);
 182
 183                         tm->tm_wday = i;
 184                         bp += len;
 185                         break;
 186
 187                 case 'B':       /* The month, using the locale's form. */
 188                 case 'b':
 189                 case 'h':
 190                         LEGAL_ALT(0);
 191                         for (i = 0; i < 12; i++) {
 192                                 /* Full name. */
 193                                 len = strlen(_ctloc(mon[i]));
 194                                 if (strncasecmp(_ctloc(mon[i]),
 195                                     (const char *)bp, len) == 0)
 196                                         break;
 197
 198                                 /* Abbreviated name. */
 199                                 len = strlen(_ctloc(abmon[i]));
 200                                 if (strncasecmp(_ctloc(abmon[i]),
 201                                     (const char *)bp, len) == 0)
 202                                         break;
 203                         }
 204
 205                         /* Nothing matched. */
 206                         if (i == 12)
 207                                 return (0);
 208
 209                         tm->tm_mon = i;
 210                         bp += len;
 211                         break;
 212
 213                 case 'C':       /* The century number. */
 214                         LEGAL_ALT(ALT_E);
 215                         if (!(conv_num(&bp, &i, 0, 99)))
 216                                 return (0);
 217
 218                         if (split_year) {
 219                                 tm->tm_year = (tm->tm_year % 100) + (i * 100);
 220                         } else {
 221                                 tm->tm_year = i * 100;
 222                                 split_year = 1;
 223                         }
 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 (0);
 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 (0);
 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 (0);
 249                         if (tm->tm_hour == 12)
 250                                 tm->tm_hour = 0;
 251                         break;
 252
 253                 case 'j':       /* The day of year. */
 254                         LEGAL_ALT(0);
 255                         if (!(conv_num(&bp, &i, 1, 366)))
 256                                 return (0);
 257                         tm->tm_yday = i - 1;
 258                         break;
 259
 260                 case 'M':       /* The minute. */
 261                         LEGAL_ALT(ALT_O);
 262                         if (!(conv_num(&bp, &tm->tm_min, 0, 59)))
 263                                 return (0);
 264                         break;
 265
 266                 case 'm':       /* The month. */
 267                         LEGAL_ALT(ALT_O);
 268                         if (!(conv_num(&bp, &i, 1, 12)))
 269                                 return (0);
 270                         tm->tm_mon = i - 1;
 271                         break;
 272
 273                 case 'p':       /* The locale's equivalent of AM/PM. */
 274                         LEGAL_ALT(0);
 275                         /* AM? */
 276                         if (strcasecmp(_ctloc(am_pm[0]),
 277                             (const char *)bp) == 0) {
 278                                 if (tm->tm_hour > 11)
 279                                         return (0);
 280
 281                                 bp += strlen(_ctloc(am_pm[0]));
 282                                 break;
 283                         }
 284                         /* PM? */
 285                         else if (strcasecmp(_ctloc(am_pm[1]),
 286                             (const char *)bp) == 0) {
 287                                 if (tm->tm_hour > 11)
 288                                         return (0);
 289
 290                                 tm->tm_hour += 12;
 291                                 bp += strlen(_ctloc(am_pm[1]));
 292                                 break;
 293                         }
 294
 295                         /* Nothing matched. */
 296                         return (0);
 297
 298                 case 'S':       /* The seconds. */
 299                         LEGAL_ALT(ALT_O);
 300                         if (!(conv_num(&bp, &tm->tm_sec, 0, 61)))
 301                                 return (0);
 302                         break;
 303
 304                 case 'U':       /* The week of year, beginning on sunday. */
 305                 case 'W':       /* The week of year, beginning on monday. */
 306                         LEGAL_ALT(ALT_O);
 307                         /*
 308                          * XXX This is bogus, as we can not assume any valid
 309                          * information present in the tm structure at this
 310                          * point to calculate a real value, so just check the
 311                          * range for now.
 312                          */
 313                          if (!(conv_num(&bp, &i, 0, 53)))
 314                                 return (0);
 315                          break;
 316
 317                 case 'w':       /* The day of week, beginning on sunday. */
 318                         LEGAL_ALT(ALT_O);
 319                         if (!(conv_num(&bp, &tm->tm_wday, 0, 6)))
 320                                 return (0);
 321                         break;
 322
 323                 case 'Y':       /* The year. */
 324                         LEGAL_ALT(ALT_E);
 325                         if (!(conv_num(&bp, &i, 0, 9999)))
 326                                 return (0);
 327
 328                         tm->tm_year = i - TM_YEAR_BASE;
 329                         break;
 330
 331                 case 'y':       /* The year within 100 years of the epoch. */
 332                         LEGAL_ALT(ALT_E | ALT_O);
 333                         if (!(conv_num(&bp, &i, 0, 99)))
 334                                 return (0);
 335
 336                         if (split_year) {
 337                                 tm->tm_year = ((tm->tm_year / 100) * 100) + i;
 338                                 break;
 339                         }
 340                         split_year = 1;
 341                         if (i <= 68)
 342                                 tm->tm_year = i + 2000 - TM_YEAR_BASE;
 343                         else
 344                                 tm->tm_year = i + 1900 - TM_YEAR_BASE;
 345                         break;
 346
 347                 /*
 348                  * Miscellaneous conversions.
 349                  */
 350                 case 'n':       /* Any kind of white-space. */
 351                 case 't':
 352                         LEGAL_ALT(0);
 353                         while (isspace(*bp))
 354                                 bp++;
 355                         break;
 356
 357
 358                 default:        /* Unknown/unsupported conversion. */
 359                         return (0);
 360                 }
 361
 362
 363         }
 364
 365         /* LINTED functional specification */
 366         return ((char *)bp);
 367 }
 368
 369
 370 static int
 371 conv_num(const unsigned char **buf, int *dest, int llim, int ulim)
 372 {
 373         int result = 0;
 374
 375         /* The limit also determines the number of valid digits. */
 376         int rulim = ulim;
 377
 378         if (**buf < '0' || **buf > '9')
 379                 return (0);
 380
 381         do {
 382                 result *= 10;
 383                 result += *(*buf)++ - '0';
 384                 rulim /= 10;
 385         } while ((result * 10 <= ulim) && rulim && **buf >= '0' && **buf <= '9');
 386
 387         if (result < llim || result > ulim)
 388                 return (0);
 389
 390         *dest = result;
 391         return (1);
 392 }