lib/libc/stdtime/strftime.c

   1 /*
   2  * Copyright (c) 1989 The Regents of the University of California.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms are permitted
   6  * provided that the above copyright notice and this paragraph are
   7  * duplicated in all such forms and that any documentation,
   8  * advertising materials, and other materials related to such
   9  * distribution and use acknowledge that the software was developed
  10  * by the University of California, Berkeley.  The name of the
  11  * University may not be used to endorse or promote products derived
  12  * from this software without specific prior written permission.
  13  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  14  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  15  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  16  *
  17  * @(#)strftime.c       7.38
  18  * $FreeBSD: src/lib/libc/stdtime/strftime.c,v 1.25.2.4 2002/03/12 17:24:54 phantom Exp $
  19  * $DragonFly: src/lib/libc/stdtime/strftime.c,v 1.4 2005/03/16 07:22:07 joerg Exp $
  20  */
  21
  22 #include "namespace.h"
  23 #include "private.h"
  24
  25 #ifndef LIBC_SCCS
  26 #ifndef lint
  27 static const char       sccsid[] = "@(#)strftime.c      5.4 (Berkeley) 3/14/89";
  28 #endif /* !defined lint */
  29 #endif /* !defined LIBC_SCCS */
  30
  31 #include "tzfile.h"
  32 #include <fcntl.h>
  33 #include <sys/stat.h>
  34 #include "un-namespace.h"
  35 #include "timelocal.h"
  36
  37 static char *   _add(const char *, char *, const char *);
  38 static char *   _conv(int, const char *, char *, const char *);
  39 static char *   _fmt(const char *, const struct tm *, char *, const char *);
  40
  41 size_t
  42 strftime(char *const s, const size_t maxsize, const char * const format,
  43          const struct tm * const t)
  44 {
  45         char *p;
  46
  47         tzset();
  48         p = _fmt(((format == NULL) ? "%c" : format), t, s, s + maxsize);
  49         if (p == s + maxsize)
  50                 return 0;
  51         *p = '\0';
  52         return p - s;
  53 }
  54
  55 static char *
  56 _fmt(const char *format, const struct tm * const t, char *pt,
  57      const char * const ptlim)
  58 {
  59         int Ealternative, Oalternative;
  60         struct lc_time_T *tptr = __get_current_time_locale();
  61
  62         for ( ; *format; ++format) {
  63                 if (*format == '%') {
  64                         Ealternative = 0;
  65                         Oalternative = 0;
  66 label:
  67                         switch (*++format) {
  68                         case '\0':
  69                                 --format;
  70                                 break;
  71                         case 'A':
  72                                 pt = _add((t->tm_wday < 0 || t->tm_wday > 6) ?
  73                                         "?" : tptr->weekday[t->tm_wday],
  74                                         pt, ptlim);
  75                                 continue;
  76                         case 'a':
  77                                 pt = _add((t->tm_wday < 0 || t->tm_wday > 6) ?
  78                                         "?" : tptr->wday[t->tm_wday],
  79                                         pt, ptlim);
  80                                 continue;
  81                         case 'B':
  82                                 pt = _add((t->tm_mon < 0 || t->tm_mon > 11) ?
  83                                         "?" : (Oalternative ? tptr->alt_month :
  84                                         tptr->month)[t->tm_mon],
  85                                         pt, ptlim);
  86                                 continue;
  87                         case 'b':
  88                         case 'h':
  89                                 pt = _add((t->tm_mon < 0 || t->tm_mon > 11) ?
  90                                         "?" : tptr->mon[t->tm_mon],
  91                                         pt, ptlim);
  92                                 continue;
  93                         case 'C':
  94                                 /*
  95                                 ** %C used to do a...
  96                                 **      _fmt("%a %b %e %X %Y", t);
  97                                 ** ...whereas now POSIX 1003.2 calls for
  98                                 ** something completely different.
  99                                 ** (ado, 1993-05-24)
 100                                 */
 101                                 pt = _conv((t->tm_year + TM_YEAR_BASE) / 100,
 102                                         "%02d", pt, ptlim);
 103                                 continue;
 104                         case 'c':
 105                                 pt = _fmt(tptr->c_fmt, t, pt, ptlim);
 106                                 continue;
 107                         case 'D':
 108                                 pt = _fmt("%m/%d/%y", t, pt, ptlim);
 109                                 continue;
 110                         case 'd':
 111                                 pt = _conv(t->tm_mday, "%02d", pt, ptlim);
 112                                 continue;
 113                         case 'E':
 114                                 if (Ealternative || Oalternative)
 115                                         break;
 116                                 Ealternative++;
 117                                 goto label;
 118                         case 'O':
 119                                 /*
 120                                 ** POSIX locale extensions, a la
 121                                 ** Arnold Robbins' strftime version 3.0.
 122                                 ** The sequences
 123                                 **      %Ec %EC %Ex %EX %Ey %EY
 124                                 **      %Od %oe %OH %OI %Om %OM
 125                                 **      %OS %Ou %OU %OV %Ow %OW %Oy
 126                                 ** are supposed to provide alternate
 127                                 ** representations.
 128                                 ** (ado, 1993-05-24)
 129                                 **
 130                                 ** FreeBSD extensions
 131                                 **      %OB %Ef %EF
 132                                 */
 133                                 if (Ealternative || Oalternative)
 134                                         break;
 135                                 Oalternative++;
 136                                 goto label;
 137                         case 'e':
 138                                 pt = _conv(t->tm_mday, "%2d", pt, ptlim);
 139                                 continue;
 140                         case 'F':
 141                                 pt = _fmt("%Y-%m-%d", t, pt, ptlim);
 142                                 continue;
 143                         case 'H':
 144                                 pt = _conv(t->tm_hour, "%02d", pt, ptlim);
 145                                 continue;
 146                         case 'I':
 147                                 pt = _conv((t->tm_hour % 12) ?
 148                                         (t->tm_hour % 12) : 12,
 149                                         "%02d", pt, ptlim);
 150                                 continue;
 151                         case 'j':
 152                                 pt = _conv(t->tm_yday + 1, "%03d", pt, ptlim);
 153                                 continue;
 154                         case 'k':
 155                                 /*
 156                                 ** This used to be...
 157                                 **      _conv(t->tm_hour % 12 ?
 158                                 **              t->tm_hour % 12 : 12, 2, ' ');
 159                                 ** ...and has been changed to the below to
 160                                 ** match SunOS 4.1.1 and Arnold Robbins'
 161                                 ** strftime version 3.0.  That is, "%k" and
 162                                 ** "%l" have been swapped.
 163                                 ** (ado, 1993-05-24)
 164                                 */
 165                                 pt = _conv(t->tm_hour, "%2d", pt, ptlim);
 166                                 continue;
 167 #ifdef KITCHEN_SINK
 168                         case 'K':
 169                                 /*
 170                                 ** After all this time, still unclaimed!
 171                                 */
 172                                 pt = _add("kitchen sink", pt, ptlim);
 173                                 continue;
 174 #endif /* defined KITCHEN_SINK */
 175                         case 'l':
 176                                 /*
 177                                 ** This used to be...
 178                                 **      _conv(t->tm_hour, 2, ' ');
 179                                 ** ...and has been changed to the below to
 180                                 ** match SunOS 4.1.1 and Arnold Robbin's
 181                                 ** strftime version 3.0.  That is, "%k" and
 182                                 ** "%l" have been swapped.
 183                                 ** (ado, 1993-05-24)
 184                                 */
 185                                 pt = _conv((t->tm_hour % 12) ?
 186                                         (t->tm_hour % 12) : 12,
 187                                         "%2d", pt, ptlim);
 188                                 continue;
 189                         case 'M':
 190                                 pt = _conv(t->tm_min, "%02d", pt, ptlim);
 191                                 continue;
 192                         case 'm':
 193                                 pt = _conv(t->tm_mon + 1, "%02d", pt, ptlim);
 194                                 continue;
 195                         case 'n':
 196                                 pt = _add("\n", pt, ptlim);
 197                                 continue;
 198                         case 'p':
 199                                 pt = _add((t->tm_hour >= 12) ?
 200                                         tptr->pm :
 201                                         tptr->am,
 202                                         pt, ptlim);
 203                                 continue;
 204                         case 'R':
 205                                 pt = _fmt("%H:%M", t, pt, ptlim);
 206                                 continue;
 207                         case 'r':
 208                                 pt = _fmt(tptr->ampm_fmt, t, pt, ptlim);
 209                                 continue;
 210                         case 'S':
 211                                 pt = _conv(t->tm_sec, "%02d", pt, ptlim);
 212                                 continue;
 213                         case 's':
 214                                 {
 215                                         struct tm       tm;
 216                                         char            buf[INT_STRLEN_MAXIMUM(
 217                                                                 time_t) + 1];
 218                                         time_t          mkt;
 219
 220                                         tm = *t;
 221                                         mkt = mktime(&tm);
 222                                         if (TYPE_SIGNED(time_t))
 223                                                 (void) sprintf(buf, "%ld",
 224                                                         (long) mkt);
 225                                         else    (void) sprintf(buf, "%lu",
 226                                                         (unsigned long) mkt);
 227                                         pt = _add(buf, pt, ptlim);
 228                                 }
 229                                 continue;
 230                         case 'T':
 231                                 pt = _fmt("%H:%M:%S", t, pt, ptlim);
 232                                 continue;
 233                         case 't':
 234                                 pt = _add("\t", pt, ptlim);
 235                                 continue;
 236                         case 'U':
 237                                 pt = _conv((t->tm_yday + 7 - t->tm_wday) / 7,
 238                                         "%02d", pt, ptlim);
 239                                 continue;
 240                         case 'u':
 241                                 /*
 242                                 ** From Arnold Robbins' strftime version 3.0:
 243                                 ** "ISO 8601: Weekday as a decimal number
 244                                 ** [1 (Monday) - 7]"
 245                                 ** (ado, 1993-05-24)
 246                                 */
 247                                 pt = _conv((t->tm_wday == 0) ? 7 : t->tm_wday,
 248                                         "%d", pt, ptlim);
 249                                 continue;
 250                         case 'V':       /* ISO 8601 week number */
 251                         case 'G':       /* ISO 8601 year (four digits) */
 252                         case 'g':       /* ISO 8601 year (two digits) */
 253 /*
 254 ** From Arnold Robbins' strftime version 3.0:  "the week number of the
 255 ** year (the first Monday as the first day of week 1) as a decimal number
 256 ** (01-53)."
 257 ** (ado, 1993-05-24)
 258 **
 259 ** From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn:
 260 ** "Week 01 of a year is per definition the first week which has the
 261 ** Thursday in this year, which is equivalent to the week which contains
 262 ** the fourth day of January. In other words, the first week of a new year
 263 ** is the week which has the majority of its days in the new year. Week 01
 264 ** might also contain days from the previous year and the week before week
 265 ** 01 of a year is the last week (52 or 53) of the previous year even if
 266 ** it contains days from the new year. A week starts with Monday (day 1)
 267 ** and ends with Sunday (day 7).  For example, the first week of the year
 268 ** 1997 lasts from 1996-12-30 to 1997-01-05..."
 269 ** (ado, 1996-01-02)
 270 */
 271                                 {
 272                                         int     year;
 273                                         int     yday;
 274                                         int     wday;
 275                                         int     w;
 276
 277                                         year = t->tm_year + TM_YEAR_BASE;
 278                                         yday = t->tm_yday;
 279                                         wday = t->tm_wday;
 280                                         for ( ; ; ) {
 281                                                 int     len;
 282                                                 int     bot;
 283                                                 int     top;
 284
 285                                                 len = isleap(year) ?
 286                                                         DAYSPERLYEAR :
 287                                                         DAYSPERNYEAR;
 288                                                 /*
 289                                                 ** What yday (-3 ... 3) does
 290                                                 ** the ISO year begin on?
 291                                                 */
 292                                                 bot = ((yday + 11 - wday) %
 293                                                         DAYSPERWEEK) - 3;
 294                                                 /*
 295                                                 ** What yday does the NEXT
 296                                                 ** ISO year begin on?
 297                                                 */
 298                                                 top = bot -
 299                                                         (len % DAYSPERWEEK);
 300                                                 if (top < -3)
 301                                                         top += DAYSPERWEEK;
 302                                                 top += len;
 303                                                 if (yday >= top) {
 304                                                         ++year;
 305                                                         w = 1;
 306                                                         break;
 307                                                 }
 308                                                 if (yday >= bot) {
 309                                                         w = 1 + ((yday - bot) /
 310                                                                 DAYSPERWEEK);
 311                                                         break;
 312                                                 }
 313                                                 --year;
 314                                                 yday += isleap(year) ?
 315                                                         DAYSPERLYEAR :
 316                                                         DAYSPERNYEAR;
 317                                         }
 318 #ifdef XPG4_1994_04_09
 319                                         if ((w == 52
 320                                              && t->tm_mon == TM_JANUARY)
 321                                             || (w == 1
 322                                                 && t->tm_mon == TM_DECEMBER))
 323                                                 w = 53;
 324 #endif /* defined XPG4_1994_04_09 */
 325                                         if (*format == 'V')
 326                                                 pt = _conv(w, "%02d",
 327                                                         pt, ptlim);
 328                                         else if (*format == 'g') {
 329                                                 pt = _conv(year % 100, "%02d",
 330                                                         pt, ptlim);
 331                                         } else  pt = _conv(year, "%04d",
 332                                                         pt, ptlim);
 333                                 }
 334                                 continue;
 335                         case 'v':
 336                                 /*
 337                                 ** From Arnold Robbins' strftime version 3.0:
 338                                 ** "date as dd-bbb-YYYY"
 339                                 ** (ado, 1993-05-24)
 340                                 */
 341                                 pt = _fmt("%e-%b-%Y", t, pt, ptlim);
 342                                 continue;
 343                         case 'W':
 344                                 pt = _conv((t->tm_yday + 7 -
 345                                         (t->tm_wday ?
 346                                         (t->tm_wday - 1) : 6)) / 7,
 347                                         "%02d", pt, ptlim);
 348                                 continue;
 349                         case 'w':
 350                                 pt = _conv(t->tm_wday, "%d", pt, ptlim);
 351                                 continue;
 352                         case 'X':
 353                                 pt = _fmt(tptr->X_fmt, t, pt, ptlim);
 354                                 continue;
 355                         case 'x':
 356                                 pt = _fmt(tptr->x_fmt, t, pt, ptlim);
 357                                 continue;
 358                         case 'y':
 359                                 pt = _conv((t->tm_year + TM_YEAR_BASE) % 100,
 360                                         "%02d", pt, ptlim);
 361                                 continue;
 362                         case 'Y':
 363                                 pt = _conv(t->tm_year + TM_YEAR_BASE, "%04d",
 364                                         pt, ptlim);
 365                                 continue;
 366                         case 'Z':
 367                                 if (t->tm_zone != NULL)
 368                                         pt = _add(t->tm_zone, pt, ptlim);
 369                                 else
 370                                 if (t->tm_isdst == 0 || t->tm_isdst == 1) {
 371                                         pt = _add(tzname[t->tm_isdst],
 372                                                 pt, ptlim);
 373                                 } else  pt = _add("?", pt, ptlim);
 374                                 continue;
 375                         case 'z':
 376                                 {
 377                                         long absoff;
 378                                         if (t->tm_gmtoff >= 0) {
 379                                                 absoff = t->tm_gmtoff;
 380                                                 pt = _add("+", pt, ptlim);
 381                                         } else {
 382                                                 absoff = -t->tm_gmtoff;
 383                                                 pt = _add("-", pt, ptlim);
 384                                         }
 385                                         pt = _conv(absoff / 3600, "%02d",
 386                                                 pt, ptlim);
 387                                         pt = _conv((absoff % 3600) / 60, "%02d",
 388                                                 pt, ptlim);
 389                                 };
 390                                 continue;
 391                         case '+':
 392                                 pt = _fmt(tptr->date_fmt, t, pt, ptlim);
 393                                 continue;
 394                         case '%':
 395                         /*
 396                          * X311J/88-090 (4.12.3.5): if conversion char is
 397                          * undefined, behavior is undefined.  Print out the
 398                          * character itself as printf(3) also does.
 399                          */
 400                         default:
 401                                 break;
 402                         }
 403                 }
 404                 if (pt == ptlim)
 405                         break;
 406                 *pt++ = *format;
 407         }
 408         return pt;
 409 }
 410
 411 static char *
 412 _conv(const int n, const char * const format, char * const pt,
 413       const char * const ptlim)
 414 {
 415         char    buf[INT_STRLEN_MAXIMUM(int) + 1];
 416
 417         (void) sprintf(buf, format, n);
 418         return _add(buf, pt, ptlim);
 419 }
 420
 421 static char *
 422 _add(const char *str, char *pt, const char * const ptlim)
 423 {
 424         while (pt < ptlim && (*pt = *str++) != '\0')
 425                 ++pt;
 426         return pt;
 427 }