lib/roken/strptime.c

   1 /*
   2  * Copyright (c) 1999 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of KTH nor the names of its contributors may be
  18  *    used to endorse or promote products derived from this software without
  19  *    specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY KTH AND ITS CONTRIBUTORS ``AS IS'' AND ANY
  22  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  24  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL KTH OR ITS CONTRIBUTORS BE
  25  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  26  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  27  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  28  * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  29  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  30  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  31  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
  32
  33 #ifdef HAVE_CONFIG_H
  34 #include <config.h>
  35 #endif
  36 #include <ctype.h>
  37 #include "roken.h"
  38
  39 RCSID("$Id$");
  40
  41 static const char *abb_weekdays[] = {
  42     "Sun",
  43     "Mon",
  44     "Tue",
  45     "Wed",
  46     "Thu",
  47     "Fri",
  48     "Sat",
  49     NULL
  50 };
  51
  52 static const char *full_weekdays[] = {
  53     "Sunday",
  54     "Monday",
  55     "Tuesday",
  56     "Wednesday",
  57     "Thursday",
  58     "Friday",
  59     "Saturday",
  60     NULL
  61 };
  62
  63 static const char *abb_month[] = {
  64     "Jan",
  65     "Feb",
  66     "Mar",
  67     "Apr",
  68     "May",
  69     "Jun",
  70     "Jul",
  71     "Aug",
  72     "Sep",
  73     "Oct",
  74     "Nov",
  75     "Dec",
  76     NULL
  77 };
  78
  79 static const char *full_month[] = {
  80     "January",
  81     "February",
  82     "Mars",
  83     "April",
  84     "May",
  85     "June",
  86     "July",
  87     "August",
  88     "September",
  89     "October",
  90     "November",
  91     "December",
  92     NULL,
  93 };
  94
  95 static const char *ampm[] = {
  96     "am",
  97     "pm",
  98     NULL
  99 };
 100
 101 /*
 102  * Try to match `*buf' to one of the strings in `strs'.  Return the
 103  * index of the matching string (or -1 if none).  Also advance buf.
 104  */
 105
 106 static int
 107 match_string (const char **buf, const char **strs)
 108 {
 109     int i = 0;
 110
 111     for (i = 0; strs[i] != NULL; ++i) {
 112         int len = strlen (strs[i]);
 113
 114         if (strncasecmp (*buf, strs[i], len) == 0) {
 115             *buf += len;
 116             return i;
 117         }
 118     }
 119     return -1;
 120 }
 121
 122 /*
 123  * tm_year is relative this year */
 124
 125 const int tm_year_base = 1900;
 126
 127 /*
 128  * Return TRUE iff `year' was a leap year.
 129  */
 130
 131 static int
 132 is_leap_year (int year)
 133 {
 134     return (year % 4) == 0 && ((year % 100) != 0 || (year % 400) == 0);
 135 }
 136
 137 /*
 138  * Return the weekday [0,6] (0 = Sunday) of the first day of `year'
 139  */
 140
 141 static int
 142 first_day (int year)
 143 {
 144     int ret = 4;
 145
 146     for (; year > 1970; --year)
 147         ret = (ret + 365 + is_leap_year (year) ? 1 : 0) % 7;
 148     return ret;
 149 }
 150
 151 /*
 152  * Set `timeptr' given `wnum' (week number [0, 53])
 153  */
 154
 155 static void
 156 set_week_number_sun (struct tm *timeptr, int wnum)
 157 {
 158     int fday = first_day (timeptr->tm_year + tm_year_base);
 159
 160     timeptr->tm_yday = wnum * 7 + timeptr->tm_wday - fday;
 161     if (timeptr->tm_yday < 0) {
 162         timeptr->tm_wday = fday;
 163         timeptr->tm_yday = 0;
 164     }
 165 }
 166
 167 /*
 168  * Set `timeptr' given `wnum' (week number [0, 53])
 169  */
 170
 171 static void
 172 set_week_number_mon (struct tm *timeptr, int wnum)
 173 {
 174     int fday = (first_day (timeptr->tm_year + tm_year_base) + 6) % 7;
 175
 176     timeptr->tm_yday = wnum * 7 + (timeptr->tm_wday + 6) % 7 - fday;
 177     if (timeptr->tm_yday < 0) {
 178         timeptr->tm_wday = (fday + 1) % 7;
 179         timeptr->tm_yday = 0;
 180     }
 181 }
 182
 183 /*
 184  * Set `timeptr' given `wnum' (week number [0, 53])
 185  */
 186
 187 static void
 188 set_week_number_mon4 (struct tm *timeptr, int wnum)
 189 {
 190     int fday = (first_day (timeptr->tm_year + tm_year_base) + 6) % 7;
 191     int offset = 0;
 192
 193     if (fday < 4)
 194         offset += 7;
 195
 196     timeptr->tm_yday = offset + (wnum - 1) * 7 + timeptr->tm_wday - fday;
 197     if (timeptr->tm_yday < 0) {
 198         timeptr->tm_wday = fday;
 199         timeptr->tm_yday = 0;
 200     }
 201 }
 202
 203 /*
 204  *
 205  */
 206
 207 char *
 208 strptime (const char *buf, const char *format, struct tm *timeptr)
 209 {
 210     char c;
 211
 212     for (; (c = *format) != '\0'; ++format) {
 213         char *s;
 214         int ret;
 215
 216         if (isspace (c)) {
 217             while (isspace (*buf))
 218                 ++buf;
 219         } else if (c == '%' && format[1] != '\0') {
 220             c = *++format;
 221             if (c == 'E' || c == 'O')
 222                 c = *++format;
 223             switch (c) {
 224             case 'A' :
 225                 ret = match_string (&buf, full_weekdays);
 226                 if (ret < 0)
 227                     return NULL;
 228                 timeptr->tm_wday = ret;
 229                 break;
 230             case 'a' :
 231                 ret = match_string (&buf, abb_weekdays);
 232                 if (ret < 0)
 233                     return NULL;
 234                 timeptr->tm_wday = ret;
 235                 break;
 236             case 'B' :
 237                 ret = match_string (&buf, full_month);
 238                 if (ret < 0)
 239                     return NULL;
 240                 timeptr->tm_mon = ret;
 241                 break;
 242             case 'b' :
 243             case 'h' :
 244                 ret = match_string (&buf, abb_month);
 245                 if (ret < 0)
 246                     return NULL;
 247                 timeptr->tm_mon = ret;
 248                 break;
 249             case 'C' :
 250                 ret = strtol (buf, &s, 10);
 251                 if (s == buf)
 252                     return NULL;
 253                 timeptr->tm_year = (ret * 100) - tm_year_base;
 254                 buf = s;
 255                 break;
 256             case 'c' :
 257                 abort ();
 258             case 'D' :          /* %m/%d/%y */
 259                 s = strptime (buf, "%m/%d/%y", timeptr);
 260                 if (s == NULL)
 261                     return NULL;
 262                 buf = s;
 263                 break;
 264             case 'd' :
 265             case 'e' :
 266                 ret = strtol (buf, &s, 10);
 267                 if (s == buf)
 268                     return NULL;
 269                 timeptr->tm_mday = ret;
 270                 buf = s;
 271                 break;
 272             case 'H' :
 273             case 'k' :
 274                 ret = strtol (buf, &s, 10);
 275                 if (s == buf)
 276                     return NULL;
 277                 timeptr->tm_hour = ret;
 278                 buf = s;
 279                 break;
 280             case 'I' :
 281             case 'l' :
 282                 ret = strtol (buf, &s, 10);
 283                 if (s == buf)
 284                     return NULL;
 285                 if (ret == 12)
 286                     timeptr->tm_hour = 0;
 287                 else
 288                     timeptr->tm_hour = ret;
 289                 buf = s;
 290                 break;
 291             case 'j' :
 292                 ret = strtol (buf, &s, 10);
 293                 if (s == buf)
 294                     return NULL;
 295                 timeptr->tm_yday = ret - 1;
 296                 buf = s;
 297                 break;
 298             case 'm' :
 299                 ret = strtol (buf, &s, 10);
 300                 if (s == buf)
 301                     return NULL;
 302                 timeptr->tm_mon = ret - 1;
 303                 buf = s;
 304                 break;
 305             case 'M' :
 306                 ret = strtol (buf, &s, 10);
 307                 if (s == buf)
 308                     return NULL;
 309                 timeptr->tm_min = ret;
 310                 buf = s;
 311                 break;
 312             case 'n' :
 313                 if (*buf == '\n')
 314                     ++buf;
 315                 else
 316                     return NULL;
 317                 break;
 318             case 'p' :
 319                 ret = match_string (&buf, ampm);
 320                 if (ret < 0)
 321                     return NULL;
 322                 if (timeptr->tm_hour == 0) {
 323                     if (ret == 1)
 324                         timeptr->tm_hour = 12;
 325                 } else
 326                     timeptr->tm_hour += 12;
 327                 break;
 328             case 'r' :          /* %I:%M:%S %p */
 329                 s = strptime (buf, "%I:%M:%S %p", timeptr);
 330                 if (s == NULL)
 331                     return NULL;
 332                 buf = s;
 333                 break;
 334             case 'R' :          /* %H:%M */
 335                 s = strptime (buf, "%H:%M", timeptr);
 336                 if (s == NULL)
 337                     return NULL;
 338                 buf = s;
 339                 break;
 340             case 'S' :
 341                 ret = strtol (buf, &s, 10);
 342                 if (s == buf)
 343                     return NULL;
 344                 timeptr->tm_sec = ret;
 345                 buf = s;
 346                 break;
 347             case 't' :
 348                 if (*buf == '\t')
 349                     ++buf;
 350                 else
 351                     return NULL;
 352                 break;
 353             case 'T' :          /* %H:%M:%S */
 354             case 'X' :
 355                 s = strptime (buf, "%H:%M:%S", timeptr);
 356                 if (s == NULL)
 357                     return NULL;
 358                 buf = s;
 359                 break;
 360             case 'u' :
 361                 ret = strtol (buf, &s, 10);
 362                 if (s == buf)
 363                     return NULL;
 364                 timeptr->tm_wday = ret - 1;
 365                 buf = s;
 366                 break;
 367             case 'w' :
 368                 ret = strtol (buf, &s, 10);
 369                 if (s == buf)
 370                     return NULL;
 371                 timeptr->tm_wday = ret;
 372                 buf = s;
 373                 break;
 374             case 'U' :
 375                 ret = strtol (buf, &s, 10);
 376                 if (s == buf)
 377                     return NULL;
 378                 set_week_number_sun (timeptr, ret);
 379                 buf = s;
 380                 break;
 381             case 'V' :
 382                 ret = strtol (buf, &s, 10);
 383                 if (s == buf)
 384                     return NULL;
 385                 set_week_number_mon4 (timeptr, ret);
 386                 buf = s;
 387                 break;
 388             case 'W' :
 389                 ret = strtol (buf, &s, 10);
 390                 if (s == buf)
 391                     return NULL;
 392                 set_week_number_mon (timeptr, ret);
 393                 buf = s;
 394                 break;
 395             case 'x' :
 396                 s = strptime (buf, "%Y:%m:%d", timeptr);
 397                 if (s == NULL)
 398                     return NULL;
 399                 buf = s;
 400                 break;
 401             case 'y' :
 402                 ret = strtol (buf, &s, 10);
 403                 if (s == buf)
 404                     return NULL;
 405                 if (ret < 70)
 406                     timeptr->tm_year = 100 + ret;
 407                 else
 408                     timeptr->tm_year = ret;
 409                 buf = s;
 410                 break;
 411             case 'Y' :
 412                 ret = strtol (buf, &s, 10);
 413                 if (s == buf)
 414                     return NULL;
 415                 timeptr->tm_year = ret - tm_year_base;
 416                 buf = s;
 417                 break;
 418             case 'Z' :
 419                 abort ();
 420             case '\0' :
 421                 --format;
 422                 /* FALLTHROUGH */
 423             case '%' :
 424                 if (*buf == '%')
 425                     ++buf;
 426                 else
 427                     return NULL;
 428                 break;
 429             default :
 430                 if (*buf == '%' || *++buf == c)
 431                     ++buf;
 432                 else
 433                     return NULL;
 434                 break;
 435             }
 436         } else {
 437             if (*buf == c)
 438                 ++buf;
 439             else
 440                 return NULL;
 441         }
 442     }
 443     return (char *)buf;
 444 }