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 1.2 2003/06/17 04:26:46 dillon Exp $
  20  */
  21
  22 #include "private.h"
  23
  24 #ifndef LIBC_SCCS
  25 #ifndef lint
  26 static const char       sccsid[] = "@(#)strftime.c      5.4 (Berkeley) 3/14/89";
  27 #endif /* !defined lint */
  28 #endif /* !defined LIBC_SCCS */
  29
  30 #include "tzfile.h"
  31 #include <fcntl.h>
  32 #include <sys/stat.h>
  33 #include "timelocal.h"
  34
  35 static char *   _add P((const char *, char *, const char *));
  36 static char *   _conv P((int, const char *, char *, const char *));
  37 static char *   _fmt P((const char *, const struct tm *, char *, const char *));
  38
  39 size_t strftime P((char *, size_t, const char *, const struct tm *));
  40
  41 extern char *   tzname[];
  42
  43 size_t
  44 strftime(s, maxsize, format, t)
  45         char *const s;
  46         const size_t maxsize;
  47         const char *const format;
  48         const struct tm *const t;
  49 {
  50         char *p;
  51
  52         tzset();
  53         p = _fmt(((format == NULL) ? "%c" : format), t, s, s + maxsize);
  54         if (p == s + maxsize)
  55                 return 0;
  56         *p = '\0';
  57         return p - s;
  58 }
  59
  60 static char *
  61 _fmt(format, t, pt, ptlim)
  62         const char *format;
  63         const struct tm *const t;
  64         char *pt;
  65         const char *const ptlim;
  66 {
  67         int Ealternative, Oalternative;
  68         struct lc_time_T *tptr = __get_current_time_locale();
  69
  70         for ( ; *format; ++format) {
  71                 if (*format == '%') {
  72                         Ealternative = 0;
  73                         Oalternative = 0;
  74 label:
  75                         switch (*++format) {
  76                         case '\0':
  77                                 --format;
  78                                 break;
  79                         case 'A':
  80                                 pt = _add((t->tm_wday < 0 || t->tm_wday > 6) ?
  81                                         "?" : tptr->weekday[t->tm_wday],
  82                                         pt, ptlim);
  83                                 continue;
  84                         case 'a':
  85                                 pt = _add((t->tm_wday < 0 || t->tm_wday > 6) ?
  86                                         "?" : tptr->wday[t->tm_wday],
  87                                         pt, ptlim);
  88                                 continue;
  89                         case 'B':
  90                                 pt = _add((t->tm_mon < 0 || t->tm_mon > 11) ?
  91                                         "?" : (Oalternative ? tptr->alt_month :
  92                                         tptr->month)[t->tm_mon],
  93                                         pt, ptlim);
  94                                 continue;
  95                         case 'b':
  96                         case 'h':
  97                                 pt = _add((t->tm_mon < 0 || t->tm_mon > 11) ?
  98                                         "?" : tptr->mon[t->tm_mon],
  99                                         pt, ptlim);
 100                                 continue;
 101                         case 'C':
 102                                 /*
 103                                 ** %C used to do a...
 104                                 **      _fmt("%a %b %e %X %Y", t);
 105                                 ** ...whereas now POSIX 1003.2 calls for
 106                                 ** something completely different.
 107                                 ** (ado, 5/24/93)
 108                                 */
 109                                 pt = _conv((t->tm_year + TM_YEAR_BASE) / 100,
 110                                         "%02d", pt, ptlim);
 111                                 continue;
 112                         case 'c':
 113                                 pt = _fmt(tptr->c_fmt, t, pt, ptlim);
 114                                 continue;
 115                         case 'D':
 116                                 pt = _fmt("%m/%d/%y", t, pt, ptlim);
 117                                 continue;
 118                         case 'd':
 119                                 pt = _conv(t->tm_mday, "%02d", pt, ptlim);
 120                                 continue;
 121                         case 'E':
 122                                 if (Ealternative || Oalternative)
 123                                         break;
 124                                 Ealternative++;
 125                                 goto label;
 126                         case 'O':
 127                                 /*
 128                                 ** POSIX locale extensions, a la
 129                                 ** Arnold Robbins' strftime version 3.0.
 130                                 ** The sequences
 131                                 **      %Ec %EC %Ex %EX %Ey %EY
 132                                 **      %Od %oe %OH %OI %Om %OM
 133                                 **      %OS %Ou %OU %OV %Ow %OW %Oy
 134                                 ** are supposed to provide alternate
 135                                 ** representations.
 136                                 ** (ado, 5/24/93)
 137                                 **
 138                                 ** FreeBSD extensions
 139                                 **      %OB %Ef %EF
 140                                 */
 141                                 if (Ealternative || Oalternative)
 142                                         break;
 143                                 Oalternative++;
 144                                 goto label;
 145                         case 'e':
 146                                 pt = _conv(t->tm_mday, "%2d", pt, ptlim);
 147                                 continue;
 148                         case 'F':
 149                                 pt = _fmt("%Y-%m-%d", t, pt, ptlim);
 150                                 continue;
 151                         case 'H':
 152                                 pt = _conv(t->tm_hour, "%02d", pt, ptlim);
 153                                 continue;
 154                         case 'I':
 155                                 pt = _conv((t->tm_hour % 12) ?
 156                                         (t->tm_hour % 12) : 12,
 157                                         "%02d", pt, ptlim);
 158                                 continue;
 159                         case 'j':
 160                                 pt = _conv(t->tm_yday + 1, "%03d", pt, ptlim);
 161                                 continue;
 162                         case 'k':
 163                                 /*
 164                                 ** This used to be...
 165                                 **      _conv(t->tm_hour % 12 ?
 166                                 **              t->tm_hour % 12 : 12, 2, ' ');
 167                                 ** ...and has been changed to the below to
 168                                 ** match SunOS 4.1.1 and Arnold Robbins'
 169                                 ** strftime version 3.0.  That is, "%k" and
 170                                 ** "%l" have been swapped.
 171                                 ** (ado, 5/24/93)
 172                                 */
 173                                 pt = _conv(t->tm_hour, "%2d", pt, ptlim);
 174                                 continue;
 175 #ifdef KITCHEN_SINK
 176                         case 'K':
 177                                 /*
 178                                 ** After all this time, still unclaimed!
 179                                 */
 180                                 pt = _add("kitchen sink", pt, ptlim);
 181                                 continue;
 182 #endif /* defined KITCHEN_SINK */
 183                         case 'l':
 184                                 /*
 185                                 ** This used to be...
 186                                 **      _conv(t->tm_hour, 2, ' ');
 187                                 ** ...and has been changed to the below to
 188                                 ** match SunOS 4.1.1 and Arnold Robbin's
 189                                 ** strftime version 3.0.  That is, "%k" and
 190                                 ** "%l" have been swapped.
 191                                 ** (ado, 5/24/93)
 192                                 */
 193                                 pt = _conv((t->tm_hour % 12) ?
 194                                         (t->tm_hour % 12) : 12,
 195                                         "%2d", pt, ptlim);
 196                                 continue;
 197                         case 'M':
 198                                 pt = _conv(t->tm_min, "%02d", pt, ptlim);
 199                                 continue;
 200                         case 'm':
 201                                 pt = _conv(t->tm_mon + 1, "%02d", pt, ptlim);
 202                                 continue;
 203                         case 'n':
 204                                 pt = _add("\n", pt, ptlim);
 205                                 continue;
 206                         case 'p':
 207                                 pt = _add((t->tm_hour >= 12) ?
 208                                         tptr->pm :
 209                                         tptr->am,
 210                                         pt, ptlim);
 211                                 continue;
 212                         case 'R':
 213                                 pt = _fmt("%H:%M", t, pt, ptlim);
 214                                 continue;
 215                         case 'r':
 216                                 pt = _fmt(tptr->ampm_fmt, t, pt, ptlim);
 217                                 continue;
 218                         case 'S':
 219                                 pt = _conv(t->tm_sec, "%02d", pt, ptlim);
 220                                 continue;
 221                         case 's':
 222                                 {
 223                                         struct tm       tm;
 224                                         char            buf[INT_STRLEN_MAXIMUM(
 225                                                                 time_t) + 1];
 226                                         time_t          mkt;
 227
 228                                         tm = *t;
 229                                         mkt = mktime(&tm);
 230                                         if (TYPE_SIGNED(time_t))
 231                                                 (void) sprintf(buf, "%ld",
 232                                                         (long) mkt);
 233                                         else    (void) sprintf(buf, "%lu",
 234                                                         (unsigned long) mkt);
 235                                         pt = _add(buf, pt, ptlim);
 236                                 }
 237                                 continue;
 238                         case 'T':
 239                                 pt = _fmt("%H:%M:%S", t, pt, ptlim);
 240                                 continue;
 241                         case 't':
 242                                 pt = _add("\t", pt, ptlim);
 243                                 continue;
 244                         case 'U':
 245                                 pt = _conv((t->tm_yday + 7 - t->tm_wday) / 7,
 246                                         "%02d", pt, ptlim);
 247                                 continue;
 248                         case 'u':
 249                                 /*
 250                                 ** From Arnold Robbins' strftime version 3.0:
 251                                 ** "ISO 8601: Weekday as a decimal number
 252                                 ** [1 (Monday) - 7]"
 253                                 ** (ado, 5/24/93)
 254                                 */
 255                                 pt = _conv((t->tm_wday == 0) ? 7 : t->tm_wday,
 256                                         "%d", pt, ptlim);
 257                                 continue;
 258                         case 'V':       /* ISO 8601 week number */
 259                         case 'G':       /* ISO 8601 year (four digits) */
 260                         case 'g':       /* ISO 8601 year (two digits) */
 261 /*
 262 ** From Arnold Robbins' strftime version 3.0:  "the week number of the
 263 ** year (the first Monday as the first day of week 1) as a decimal number
 264 ** (01-53)."
 265 ** (ado, 1993-05-24)
 266 **
 267 ** From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn:
 268 ** "Week 01 of a year is per definition the first week which has the
 269 ** Thursday in this year, which is equivalent to the week which contains
 270 ** the fourth day of January. In other words, the first week of a new year
 271 ** is the week which has the majority of its days in the new year. Week 01
 272 ** might also contain days from the previous year and the week before week
 273 ** 01 of a year is the last week (52 or 53) of the previous year even if
 274 ** it contains days from the new year. A week starts with Monday (day 1)
 275 ** and ends with Sunday (day 7).  For example, the first week of the year
 276 ** 1997 lasts from 1996-12-30 to 1997-01-05..."
 277 ** (ado, 1996-01-02)
 278 */
 279                                 {
 280                                         int     year;
 281                                         int     yday;
 282                                         int     wday;
 283                                         int     w;
 284
 285                                         year = t->tm_year + TM_YEAR_BASE;
 286                                         yday = t->tm_yday;
 287                                         wday = t->tm_wday;
 288                                         for ( ; ; ) {
 289                                                 int     len;
 290                                                 int     bot;
 291                                                 int     top;
 292
 293                                                 len = isleap(year) ?
 294                                                         DAYSPERLYEAR :
 295                                                         DAYSPERNYEAR;
 296                                                 /*
 297                                                 ** What yday (-3 ... 3) does
 298                                                 ** the ISO year begin on?
 299                                                 */
 300                                                 bot = ((yday + 11 - wday) %
 301                                                         DAYSPERWEEK) - 3;
 302                                                 /*
 303                                                 ** What yday does the NEXT
 304                                                 ** ISO year begin on?
 305                                                 */
 306                                                 top = bot -
 307                                                         (len % DAYSPERWEEK);
 308                                                 if (top < -3)
 309                                                         top += DAYSPERWEEK;
 310                                                 top += len;
 311                                                 if (yday >= top) {
 312                                                         ++year;
 313                                                         w = 1;
 314                                                         break;
 315                                                 }
 316                                                 if (yday >= bot) {
 317                                                         w = 1 + ((yday - bot) /
 318                                                                 DAYSPERWEEK);
 319                                                         break;
 320                                                 }
 321                                                 --year;
 322                                                 yday += isleap(year) ?
 323                                                         DAYSPERLYEAR :
 324                                                         DAYSPERNYEAR;
 325                                         }
 326 #ifdef XPG4_1994_04_09
 327                                         if ((w == 52
 328                                              && t->tm_mon == TM_JANUARY)
 329                                             || (w == 1
 330                                                 && t->tm_mon == TM_DECEMBER))
 331                                                 w = 53;
 332 #endif /* defined XPG4_1994_04_09 */
 333                                         if (*format == 'V')
 334                                                 pt = _conv(w, "%02d",
 335                                                         pt, ptlim);
 336                                         else if (*format == 'g') {
 337                                                 pt = _conv(year % 100, "%02d",
 338                                                         pt, ptlim);
 339                                         } else  pt = _conv(year, "%04d",
 340                                                         pt, ptlim);
 341                                 }
 342                                 continue;
 343                         case 'v':
 344                                 /*
 345                                 ** From Arnold Robbins' strftime version 3.0:
 346                                 ** "date as dd-bbb-YYYY"
 347                                 ** (ado, 5/24/93)
 348                                 */
 349                                 pt = _fmt("%e-%b-%Y", t, pt, ptlim);
 350                                 continue;
 351                         case 'W':
 352                                 pt = _conv((t->tm_yday + 7 -
 353                                         (t->tm_wday ?
 354                                         (t->tm_wday - 1) : 6)) / 7,
 355                                         "%02d", pt, ptlim);
 356                                 continue;
 357                         case 'w':
 358                                 pt = _conv(t->tm_wday, "%d", pt, ptlim);
 359                                 continue;
 360                         case 'X':
 361                                 pt = _fmt(tptr->X_fmt, t, pt, ptlim);
 362                                 continue;
 363                         case 'x':
 364                                 pt = _fmt(tptr->x_fmt, t, pt, ptlim);
 365                                 continue;
 366                         case 'y':
 367                                 pt = _conv((t->tm_year + TM_YEAR_BASE) % 100,
 368                                         "%02d", pt, ptlim);
 369                                 continue;
 370                         case 'Y':
 371                                 pt = _conv(t->tm_year + TM_YEAR_BASE, "%04d",
 372                                         pt, ptlim);
 373                                 continue;
 374                         case 'Z':
 375                                 if (t->tm_zone != NULL)
 376                                         pt = _add(t->tm_zone, pt, ptlim);
 377                                 else
 378                                 if (t->tm_isdst == 0 || t->tm_isdst == 1) {
 379                                         pt = _add(tzname[t->tm_isdst],
 380                                                 pt, ptlim);
 381                                 } else  pt = _add("?", pt, ptlim);
 382                                 continue;
 383                         case 'z':
 384                                 {
 385                                         long absoff;
 386                                         if (t->tm_gmtoff >= 0) {
 387                                                 absoff = t->tm_gmtoff;
 388                                                 pt = _add("+", pt, ptlim);
 389                                         } else {
 390                                                 absoff = -t->tm_gmtoff;
 391                                                 pt = _add("-", pt, ptlim);
 392                                         }
 393                                         pt = _conv(absoff / 3600, "%02d",
 394                                                 pt, ptlim);
 395                                         pt = _conv((absoff % 3600) / 60, "%02d",
 396                                                 pt, ptlim);
 397                                 };
 398                                 continue;
 399                         case '+':
 400                                 pt = _fmt(tptr->date_fmt, t, pt, ptlim);
 401                                 continue;
 402                         case '%':
 403                         /*
 404                          * X311J/88-090 (4.12.3.5): if conversion char is
 405                          * undefined, behavior is undefined.  Print out the
 406                          * character itself as printf(3) also does.
 407                          */
 408                         default:
 409                                 break;
 410                         }
 411                 }
 412                 if (pt == ptlim)
 413                         break;
 414                 *pt++ = *format;
 415         }
 416         return pt;
 417 }
 418
 419 static char *
 420 _conv(n, format, pt, ptlim)
 421         const int n;
 422         const char *const format;
 423         char *const pt;
 424         const char *const ptlim;
 425 {
 426         char    buf[INT_STRLEN_MAXIMUM(int) + 1];
 427
 428         (void) sprintf(buf, format, n);
 429         return _add(buf, pt, ptlim);
 430 }
 431
 432 static char *
 433 _add(str, pt, ptlim)
 434         const char *str;
 435         char *pt;
 436         const char *const ptlim;
 437 {
 438         while (pt < ptlim && (*pt = *str++) != '\0')
 439                 ++pt;
 440         return pt;
 441 }