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
  18 #ifdef LIBC_RCS
  19 static const char rcsid[] =
  20   "$FreeBSD: src/lib/libc/stdtime/strftime.c,v 1.25.2.4 2002/03/12 17:24:54 phantom Exp $";
  21 #endif
  22
  23 #ifndef lint
  24 #ifndef NOID
  25 static const char       elsieid[] = "@(#)strftime.c     7.38";
  26 /*
  27 ** Based on the UCB version with the ID appearing below.
  28 ** This is ANSIish only when "multibyte character == plain character".
  29 */
  30 #endif /* !defined NOID */
  31 #endif /* !defined lint */
  32
  33 #include "private.h"
  34
  35 #ifndef LIBC_SCCS
  36 #ifndef lint
  37 static const char       sccsid[] = "@(#)strftime.c      5.4 (Berkeley) 3/14/89";
  38 #endif /* !defined lint */
  39 #endif /* !defined LIBC_SCCS */
  40
  41 #include "tzfile.h"
  42 #include <fcntl.h>
  43 #include <sys/stat.h>
  44 #include "timelocal.h"
  45
  46 static char *   _add P((const char *, char *, const char *));
  47 static char *   _conv P((int, const char *, char *, const char *));
  48 static char *   _fmt P((const char *, const struct tm *, char *, const char *));
  49
  50 size_t strftime P((char *, size_t, const char *, const struct tm *));
  51
  52 extern char *   tzname[];
  53
  54 size_t
  55 strftime(s, maxsize, format, t)
  56         char *const s;
  57         const size_t maxsize;
  58         const char *const format;
  59         const struct tm *const t;
  60 {
  61         char *p;
  62
  63         tzset();
  64         p = _fmt(((format == NULL) ? "%c" : format), t, s, s + maxsize);
  65         if (p == s + maxsize)
  66                 return 0;
  67         *p = '\0';
  68         return p - s;
  69 }
  70
  71 static char *
  72 _fmt(format, t, pt, ptlim)
  73         const char *format;
  74         const struct tm *const t;
  75         char *pt;
  76         const char *const ptlim;
  77 {
  78         int Ealternative, Oalternative;
  79         struct lc_time_T *tptr = __get_current_time_locale();
  80
  81         for ( ; *format; ++format) {
  82                 if (*format == '%') {
  83                         Ealternative = 0;
  84                         Oalternative = 0;
  85 label:
  86                         switch (*++format) {
  87                         case '\0':
  88                                 --format;
  89                                 break;
  90                         case 'A':
  91                                 pt = _add((t->tm_wday < 0 || t->tm_wday > 6) ?
  92                                         "?" : tptr->weekday[t->tm_wday],
  93                                         pt, ptlim);
  94                                 continue;
  95                         case 'a':
  96                                 pt = _add((t->tm_wday < 0 || t->tm_wday > 6) ?
  97                                         "?" : tptr->wday[t->tm_wday],
  98                                         pt, ptlim);
  99                                 continue;
 100                         case 'B':
 101                                 pt = _add((t->tm_mon < 0 || t->tm_mon > 11) ?
 102                                         "?" : (Oalternative ? tptr->alt_month :
 103                                         tptr->month)[t->tm_mon],
 104                                         pt, ptlim);
 105                                 continue;
 106                         case 'b':
 107                         case 'h':
 108                                 pt = _add((t->tm_mon < 0 || t->tm_mon > 11) ?
 109                                         "?" : tptr->mon[t->tm_mon],
 110                                         pt, ptlim);
 111                                 continue;
 112                         case 'C':
 113                                 /*
 114                                 ** %C used to do a...
 115                                 **      _fmt("%a %b %e %X %Y", t);
 116                                 ** ...whereas now POSIX 1003.2 calls for
 117                                 ** something completely different.
 118                                 ** (ado, 5/24/93)
 119                                 */
 120                                 pt = _conv((t->tm_year + TM_YEAR_BASE) / 100,
 121                                         "%02d", pt, ptlim);
 122                                 continue;
 123                         case 'c':
 124                                 pt = _fmt(tptr->c_fmt, t, pt, ptlim);
 125                                 continue;
 126                         case 'D':
 127                                 pt = _fmt("%m/%d/%y", t, pt, ptlim);
 128                                 continue;
 129                         case 'd':
 130                                 pt = _conv(t->tm_mday, "%02d", pt, ptlim);
 131                                 continue;
 132                         case 'E':
 133                                 if (Ealternative || Oalternative)
 134                                         break;
 135                                 Ealternative++;
 136                                 goto label;
 137                         case 'O':
 138                                 /*
 139                                 ** POSIX locale extensions, a la
 140                                 ** Arnold Robbins' strftime version 3.0.
 141                                 ** The sequences
 142                                 **      %Ec %EC %Ex %EX %Ey %EY
 143                                 **      %Od %oe %OH %OI %Om %OM
 144                                 **      %OS %Ou %OU %OV %Ow %OW %Oy
 145                                 ** are supposed to provide alternate
 146                                 ** representations.
 147                                 ** (ado, 5/24/93)
 148                                 **
 149                                 ** FreeBSD extensions
 150                                 **      %OB %Ef %EF
 151                                 */
 152                                 if (Ealternative || Oalternative)
 153                                         break;
 154                                 Oalternative++;
 155                                 goto label;
 156                         case 'e':
 157                                 pt = _conv(t->tm_mday, "%2d", pt, ptlim);
 158                                 continue;
 159                         case 'F':
 160                                 pt = _fmt("%Y-%m-%d", t, pt, ptlim);
 161                                 continue;
 162                         case 'H':
 163                                 pt = _conv(t->tm_hour, "%02d", pt, ptlim);
 164                                 continue;
 165                         case 'I':
 166                                 pt = _conv((t->tm_hour % 12) ?
 167                                         (t->tm_hour % 12) : 12,
 168                                         "%02d", pt, ptlim);
 169                                 continue;
 170                         case 'j':
 171                                 pt = _conv(t->tm_yday + 1, "%03d", pt, ptlim);
 172                                 continue;
 173                         case 'k':
 174                                 /*
 175                                 ** This used to be...
 176                                 **      _conv(t->tm_hour % 12 ?
 177                                 **              t->tm_hour % 12 : 12, 2, ' ');
 178                                 ** ...and has been changed to the below to
 179                                 ** match SunOS 4.1.1 and Arnold Robbins'
 180                                 ** strftime version 3.0.  That is, "%k" and
 181                                 ** "%l" have been swapped.
 182                                 ** (ado, 5/24/93)
 183                                 */
 184                                 pt = _conv(t->tm_hour, "%2d", pt, ptlim);
 185                                 continue;
 186 #ifdef KITCHEN_SINK
 187                         case 'K':
 188                                 /*
 189                                 ** After all this time, still unclaimed!
 190                                 */
 191                                 pt = _add("kitchen sink", pt, ptlim);
 192                                 continue;
 193 #endif /* defined KITCHEN_SINK */
 194                         case 'l':
 195                                 /*
 196                                 ** This used to be...
 197                                 **      _conv(t->tm_hour, 2, ' ');
 198                                 ** ...and has been changed to the below to
 199                                 ** match SunOS 4.1.1 and Arnold Robbin's
 200                                 ** strftime version 3.0.  That is, "%k" and
 201                                 ** "%l" have been swapped.
 202                                 ** (ado, 5/24/93)
 203                                 */
 204                                 pt = _conv((t->tm_hour % 12) ?
 205                                         (t->tm_hour % 12) : 12,
 206                                         "%2d", pt, ptlim);
 207                                 continue;
 208                         case 'M':
 209                                 pt = _conv(t->tm_min, "%02d", pt, ptlim);
 210                                 continue;
 211                         case 'm':
 212                                 pt = _conv(t->tm_mon + 1, "%02d", pt, ptlim);
 213                                 continue;
 214                         case 'n':
 215                                 pt = _add("\n", pt, ptlim);
 216                                 continue;
 217                         case 'p':
 218                                 pt = _add((t->tm_hour >= 12) ?
 219                                         tptr->pm :
 220                                         tptr->am,
 221                                         pt, ptlim);
 222                                 continue;
 223                         case 'R':
 224                                 pt = _fmt("%H:%M", t, pt, ptlim);
 225                                 continue;
 226                         case 'r':
 227                                 pt = _fmt(tptr->ampm_fmt, t, pt, ptlim);
 228                                 continue;
 229                         case 'S':
 230                                 pt = _conv(t->tm_sec, "%02d", pt, ptlim);
 231                                 continue;
 232                         case 's':
 233                                 {
 234                                         struct tm       tm;
 235                                         char            buf[INT_STRLEN_MAXIMUM(
 236                                                                 time_t) + 1];
 237                                         time_t          mkt;
 238
 239                                         tm = *t;
 240                                         mkt = mktime(&tm);
 241                                         if (TYPE_SIGNED(time_t))
 242                                                 (void) sprintf(buf, "%ld",
 243                                                         (long) mkt);
 244                                         else    (void) sprintf(buf, "%lu",
 245                                                         (unsigned long) mkt);
 246                                         pt = _add(buf, pt, ptlim);
 247                                 }
 248                                 continue;
 249                         case 'T':
 250                                 pt = _fmt("%H:%M:%S", t, pt, ptlim);
 251                                 continue;
 252                         case 't':
 253                                 pt = _add("\t", pt, ptlim);
 254                                 continue;
 255                         case 'U':
 256                                 pt = _conv((t->tm_yday + 7 - t->tm_wday) / 7,
 257                                         "%02d", pt, ptlim);
 258                                 continue;
 259                         case 'u':
 260                                 /*
 261                                 ** From Arnold Robbins' strftime version 3.0:
 262                                 ** "ISO 8601: Weekday as a decimal number
 263                                 ** [1 (Monday) - 7]"
 264                                 ** (ado, 5/24/93)
 265                                 */
 266                                 pt = _conv((t->tm_wday == 0) ? 7 : t->tm_wday,
 267                                         "%d", pt, ptlim);
 268                                 continue;
 269                         case 'V':       /* ISO 8601 week number */
 270                         case 'G':       /* ISO 8601 year (four digits) */
 271                         case 'g':       /* ISO 8601 year (two digits) */
 272 /*
 273 ** From Arnold Robbins' strftime version 3.0:  "the week number of the
 274 ** year (the first Monday as the first day of week 1) as a decimal number
 275 ** (01-53)."
 276 ** (ado, 1993-05-24)
 277 **
 278 ** From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn:
 279 ** "Week 01 of a year is per definition the first week which has the
 280 ** Thursday in this year, which is equivalent to the week which contains
 281 ** the fourth day of January. In other words, the first week of a new year
 282 ** is the week which has the majority of its days in the new year. Week 01
 283 ** might also contain days from the previous year and the week before week
 284 ** 01 of a year is the last week (52 or 53) of the previous year even if
 285 ** it contains days from the new year. A week starts with Monday (day 1)
 286 ** and ends with Sunday (day 7).  For example, the first week of the year
 287 ** 1997 lasts from 1996-12-30 to 1997-01-05..."
 288 ** (ado, 1996-01-02)
 289 */
 290                                 {
 291                                         int     year;
 292                                         int     yday;
 293                                         int     wday;
 294                                         int     w;
 295
 296                                         year = t->tm_year + TM_YEAR_BASE;
 297                                         yday = t->tm_yday;
 298                                         wday = t->tm_wday;
 299                                         for ( ; ; ) {
 300                                                 int     len;
 301                                                 int     bot;
 302                                                 int     top;
 303
 304                                                 len = isleap(year) ?
 305                                                         DAYSPERLYEAR :
 306                                                         DAYSPERNYEAR;
 307                                                 /*
 308                                                 ** What yday (-3 ... 3) does
 309                                                 ** the ISO year begin on?
 310                                                 */
 311                                                 bot = ((yday + 11 - wday) %
 312                                                         DAYSPERWEEK) - 3;
 313                                                 /*
 314                                                 ** What yday does the NEXT
 315                                                 ** ISO year begin on?
 316                                                 */
 317                                                 top = bot -
 318                                                         (len % DAYSPERWEEK);
 319                                                 if (top < -3)
 320                                                         top += DAYSPERWEEK;
 321                                                 top += len;
 322                                                 if (yday >= top) {
 323                                                         ++year;
 324                                                         w = 1;
 325                                                         break;
 326                                                 }
 327                                                 if (yday >= bot) {
 328                                                         w = 1 + ((yday - bot) /
 329                                                                 DAYSPERWEEK);
 330                                                         break;
 331                                                 }
 332                                                 --year;
 333                                                 yday += isleap(year) ?
 334                                                         DAYSPERLYEAR :
 335                                                         DAYSPERNYEAR;
 336                                         }
 337 #ifdef XPG4_1994_04_09
 338                                         if ((w == 52
 339                                              && t->tm_mon == TM_JANUARY)
 340                                             || (w == 1
 341                                                 && t->tm_mon == TM_DECEMBER))
 342                                                 w = 53;
 343 #endif /* defined XPG4_1994_04_09 */
 344                                         if (*format == 'V')
 345                                                 pt = _conv(w, "%02d",
 346                                                         pt, ptlim);
 347                                         else if (*format == 'g') {
 348                                                 pt = _conv(year % 100, "%02d",
 349                                                         pt, ptlim);
 350                                         } else  pt = _conv(year, "%04d",
 351                                                         pt, ptlim);
 352                                 }
 353                                 continue;
 354                         case 'v':
 355                                 /*
 356                                 ** From Arnold Robbins' strftime version 3.0:
 357                                 ** "date as dd-bbb-YYYY"
 358                                 ** (ado, 5/24/93)
 359                                 */
 360                                 pt = _fmt("%e-%b-%Y", t, pt, ptlim);
 361                                 continue;
 362                         case 'W':
 363                                 pt = _conv((t->tm_yday + 7 -
 364                                         (t->tm_wday ?
 365                                         (t->tm_wday - 1) : 6)) / 7,
 366                                         "%02d", pt, ptlim);
 367                                 continue;
 368                         case 'w':
 369                                 pt = _conv(t->tm_wday, "%d", pt, ptlim);
 370                                 continue;
 371                         case 'X':
 372                                 pt = _fmt(tptr->X_fmt, t, pt, ptlim);
 373                                 continue;
 374                         case 'x':
 375                                 pt = _fmt(tptr->x_fmt, t, pt, ptlim);
 376                                 continue;
 377                         case 'y':
 378                                 pt = _conv((t->tm_year + TM_YEAR_BASE) % 100,
 379                                         "%02d", pt, ptlim);
 380                                 continue;
 381                         case 'Y':
 382                                 pt = _conv(t->tm_year + TM_YEAR_BASE, "%04d",
 383                                         pt, ptlim);
 384                                 continue;
 385                         case 'Z':
 386                                 if (t->tm_zone != NULL)
 387                                         pt = _add(t->tm_zone, pt, ptlim);
 388                                 else
 389                                 if (t->tm_isdst == 0 || t->tm_isdst == 1) {
 390                                         pt = _add(tzname[t->tm_isdst],
 391                                                 pt, ptlim);
 392                                 } else  pt = _add("?", pt, ptlim);
 393                                 continue;
 394                         case 'z':
 395                                 {
 396                                         long absoff;
 397                                         if (t->tm_gmtoff >= 0) {
 398                                                 absoff = t->tm_gmtoff;
 399                                                 pt = _add("+", pt, ptlim);
 400                                         } else {
 401                                                 absoff = -t->tm_gmtoff;
 402                                                 pt = _add("-", pt, ptlim);
 403                                         }
 404                                         pt = _conv(absoff / 3600, "%02d",
 405                                                 pt, ptlim);
 406                                         pt = _conv((absoff % 3600) / 60, "%02d",
 407                                                 pt, ptlim);
 408                                 };
 409                                 continue;
 410                         case '+':
 411                                 pt = _fmt(tptr->date_fmt, t, pt, ptlim);
 412                                 continue;
 413                         case '%':
 414                         /*
 415                          * X311J/88-090 (4.12.3.5): if conversion char is
 416                          * undefined, behavior is undefined.  Print out the
 417                          * character itself as printf(3) also does.
 418                          */
 419                         default:
 420                                 break;
 421                         }
 422                 }
 423                 if (pt == ptlim)
 424                         break;
 425                 *pt++ = *format;
 426         }
 427         return pt;
 428 }
 429
 430 static char *
 431 _conv(n, format, pt, ptlim)
 432         const int n;
 433         const char *const format;
 434         char *const pt;
 435         const char *const ptlim;
 436 {
 437         char    buf[INT_STRLEN_MAXIMUM(int) + 1];
 438
 439         (void) sprintf(buf, format, n);
 440         return _add(buf, pt, ptlim);
 441 }
 442
 443 static char *
 444 _add(str, pt, ptlim)
 445         const char *str;
 446         char *pt;
 447         const char *const ptlim;
 448 {
 449         while (pt < ptlim && (*pt = *str++) != '\0')
 450                 ++pt;
 451         return pt;
 452 }