lib/libc/time/strftime.c

   1 /*      $NetBSD: strftime.c,v 1.35 2015/10/09 17:21:45 christos Exp $   */
   2
   3 #include <sys/cdefs.h>
   4 #if defined(LIBC_SCCS) && !defined(lint)
   5 #if 0
   6 static char     elsieid[] = "@(#)strftime.c     7.64";
   7 static char     elsieid[] = "@(#)strftime.c     8.3";
   8 #else
   9 __RCSID("$NetBSD: strftime.c,v 1.35 2015/10/09 17:21:45 christos Exp $");
  10 #endif
  11 #endif /* LIBC_SCCS and not lint */
  12
  13 #include "namespace.h"
  14
  15 #include <stddef.h>
  16 #include <assert.h>
  17 #include <locale.h>
  18 #include "setlocale_local.h"
  19
  20 /*
  21 ** Based on the UCB version with the copyright notice and sccsid
  22 ** appearing below.
  23 **
  24 ** This is ANSIish only when "multibyte character == plain character".
  25 */
  26
  27 #include "private.h"
  28
  29 /*
  30 ** We don't use these extensions in strftime operation even when
  31 ** supported by the local tzcode configuration.  A strictly
  32 ** conforming C application may leave them in undefined state.
  33 */
  34
  35 #ifdef _LIBC
  36 #undef TM_ZONE
  37 #undef TM_GMTOFF
  38 #endif
  39
  40 /*
  41 ** Copyright (c) 1989, 1993
  42 **      The Regents of the University of California.  All rights reserved.
  43 **
  44 ** Redistribution and use in source and binary forms, with or without
  45 ** modification, are permitted provided that the following conditions
  46 ** are met:
  47 ** 1. Redistributions of source code must retain the above copyright
  48 **    notice, this list of conditions and the following disclaimer.
  49 ** 2. Redistributions in binary form must reproduce the above copyright
  50 **    notice, this list of conditions and the following disclaimer in the
  51 **    documentation and/or other materials provided with the distribution.
  52 ** 3. All advertising materials mentioning features or use of this software
  53 **    must display the following acknowledgement:
  54 **      This product includes software developed by the University of
  55 **      California, Berkeley and its contributors.
  56 ** 4. Neither the name of the University nor the names of its contributors
  57 **    may be used to endorse or promote products derived from this software
  58 **    without specific prior written permission.
  59 **
  60 ** THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS" AND
  61 ** ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  62 ** IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  63 ** ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  64 ** FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  65 ** DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  66 ** OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  67 ** HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  68 ** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  69 ** OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  70 ** SUCH DAMAGE.
  71 */
  72
  73 #include "tzfile.h"
  74 #include "fcntl.h"
  75 #include "locale.h"
  76
  77 #ifdef __weak_alias
  78 __weak_alias(strftime_l, _strftime_l)
  79 __weak_alias(strftime_lz, _strftime_lz)
  80 __weak_alias(strftime_z, _strftime_z)
  81 #endif
  82
  83 #include "sys/localedef.h"
  84 #define _TIME_LOCALE(loc) \
  85     ((_TimeLocale *)((loc)->part_impl[(size_t)LC_TIME]))
  86 #define c_fmt   d_t_fmt
  87
  88 static char *   _add(const char *, char *, const char *);
  89 static char *   _conv(int, const char *, char *, const char *);
  90 static char *   _fmt(const timezone_t, const char *, const struct tm *, char *,
  91                         const char *, int *, locale_t);
  92 static char *   _yconv(int, int, bool, bool, char *, const char *);
  93
  94 extern char *   tzname[];
  95
  96 #ifndef YEAR_2000_NAME
  97 #define YEAR_2000_NAME  "CHECK_STRFTIME_FORMATS_FOR_TWO_DIGIT_YEARS"
  98 #endif /* !defined YEAR_2000_NAME */
  99
 100 #define IN_NONE 0
 101 #define IN_SOME 1
 102 #define IN_THIS 2
 103 #define IN_ALL  3
 104
 105 size_t
 106 strftime_z(const timezone_t sp, char * __restrict s, size_t maxsize,
 107     const char * __restrict format, const struct tm * __restrict t)
 108 {
 109         return strftime_lz(sp, s, maxsize, format, t, _current_locale());
 110 }
 111
 112 #if HAVE_STRFTIME_L
 113 size_t
 114 strftime_l(char *s, size_t maxsize, char const *format, struct tm const *t,
 115            locale_t locale)
 116 {
 117   /* Just call strftime, as only the C locale is supported.  */
 118   return strftime(s, maxsize, format, t);
 119 }
 120 #endif
 121
 122 size_t
 123 strftime_lz(const timezone_t sp, char *const s, const size_t maxsize,
 124     const char *const format, const struct tm *const t, locale_t loc)
 125 {
 126         char *  p;
 127         int     warn;
 128
 129         warn = IN_NONE;
 130         p = _fmt(sp, ((format == NULL) ? "%c" : format), t, s, s + maxsize,
 131             &warn, loc);
 132 #ifndef NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU
 133         if (warn != IN_NONE && getenv(YEAR_2000_NAME) != NULL) {
 134                 (void) fprintf(stderr, "\n");
 135                 if (format == NULL)
 136                         (void) fprintf(stderr, "NULL strftime format ");
 137                 else    (void) fprintf(stderr, "strftime format \"%s\" ",
 138                                 format);
 139                 (void) fprintf(stderr, "yields only two digits of years in ");
 140                 if (warn == IN_SOME)
 141                         (void) fprintf(stderr, "some locales");
 142                 else if (warn == IN_THIS)
 143                         (void) fprintf(stderr, "the current locale");
 144                 else    (void) fprintf(stderr, "all locales");
 145                 (void) fprintf(stderr, "\n");
 146         }
 147 #endif /* !defined NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU */
 148         if (p == s + maxsize)
 149                 return 0;
 150         *p = '\0';
 151         return p - s;
 152 }
 153
 154 static char *
 155 _fmt(const timezone_t sp, const char *format, const struct tm *t, char *pt,
 156      const char *ptlim, int *warnp, locale_t loc)
 157 {
 158         for ( ; *format; ++format) {
 159                 if (*format == '%') {
 160 label:
 161                         switch (*++format) {
 162                         case '\0':
 163                                 --format;
 164                                 break;
 165                         case 'A':
 166                                 pt = _add((t->tm_wday < 0 ||
 167                                         t->tm_wday >= DAYSPERWEEK) ?
 168                                         "?" : _TIME_LOCALE(loc)->day[t->tm_wday],
 169                                         pt, ptlim);
 170                                 continue;
 171                         case 'a':
 172                                 pt = _add((t->tm_wday < 0 ||
 173                                         t->tm_wday >= DAYSPERWEEK) ?
 174                                         "?" : _TIME_LOCALE(loc)->abday[t->tm_wday],
 175                                         pt, ptlim);
 176                                 continue;
 177                         case 'B':
 178                                 pt = _add((t->tm_mon < 0 ||
 179                                         t->tm_mon >= MONSPERYEAR) ?
 180                                         "?" : _TIME_LOCALE(loc)->mon[t->tm_mon],
 181                                         pt, ptlim);
 182                                 continue;
 183                         case 'b':
 184                         case 'h':
 185                                 pt = _add((t->tm_mon < 0 ||
 186                                         t->tm_mon >= MONSPERYEAR) ?
 187                                         "?" : _TIME_LOCALE(loc)->abmon[t->tm_mon],
 188                                         pt, ptlim);
 189                                 continue;
 190                         case 'C':
 191                                 /*
 192                                 ** %C used to do a...
 193                                 **      _fmt("%a %b %e %X %Y", t);
 194                                 ** ...whereas now POSIX 1003.2 calls for
 195                                 ** something completely different.
 196                                 ** (ado, 1993-05-24)
 197                                 */
 198                                 pt = _yconv(t->tm_year, TM_YEAR_BASE,
 199                                             true, false, pt, ptlim);
 200                                 continue;
 201                         case 'c':
 202                                 {
 203                                 int warn2 = IN_SOME;
 204
 205                                 pt = _fmt(sp, _TIME_LOCALE(loc)->c_fmt, t, pt,
 206                                     ptlim, &warn2, loc);
 207                                 if (warn2 == IN_ALL)
 208                                         warn2 = IN_THIS;
 209                                 if (warn2 > *warnp)
 210                                         *warnp = warn2;
 211                                 }
 212                                 continue;
 213                         case 'D':
 214                                 pt = _fmt(sp, "%m/%d/%y", t, pt, ptlim, warnp,
 215                                     loc);
 216                                 continue;
 217                         case 'd':
 218                                 pt = _conv(t->tm_mday, "%02d", pt, ptlim);
 219                                 continue;
 220                         case 'E':
 221                         case 'O':
 222                                 /*
 223                                 ** C99 locale modifiers.
 224                                 ** The sequences
 225                                 **      %Ec %EC %Ex %EX %Ey %EY
 226                                 **      %Od %oe %OH %OI %Om %OM
 227                                 **      %OS %Ou %OU %OV %Ow %OW %Oy
 228                                 ** are supposed to provide alternate
 229                                 ** representations.
 230                                 */
 231                                 goto label;
 232                         case 'e':
 233                                 pt = _conv(t->tm_mday, "%2d", pt, ptlim);
 234                                 continue;
 235                         case 'F':
 236                                 pt = _fmt(sp, "%Y-%m-%d", t, pt, ptlim, warnp,
 237                                     loc);
 238                                 continue;
 239                         case 'H':
 240                                 pt = _conv(t->tm_hour, "%02d", pt, ptlim);
 241                                 continue;
 242                         case 'I':
 243                                 pt = _conv((t->tm_hour % 12) ?
 244                                         (t->tm_hour % 12) : 12,
 245                                         "%02d", pt, ptlim);
 246                                 continue;
 247                         case 'j':
 248                                 pt = _conv(t->tm_yday + 1, "%03d", pt, ptlim);
 249                                 continue;
 250                         case 'k':
 251                                 /*
 252                                 ** This used to be...
 253                                 **      _conv(t->tm_hour % 12 ?
 254                                 **              t->tm_hour % 12 : 12, 2, ' ');
 255                                 ** ...and has been changed to the below to
 256                                 ** match SunOS 4.1.1 and Arnold Robbins'
 257                                 ** strftime version 3.0. That is, "%k" and
 258                                 ** "%l" have been swapped.
 259                                 ** (ado, 1993-05-24)
 260                                 */
 261                                 pt = _conv(t->tm_hour, "%2d", pt, ptlim);
 262                                 continue;
 263 #ifdef KITCHEN_SINK
 264                         case 'K':
 265                                 /*
 266                                 ** After all this time, still unclaimed!
 267                                 */
 268                                 pt = _add("kitchen sink", pt, ptlim);
 269                                 continue;
 270 #endif /* defined KITCHEN_SINK */
 271                         case 'l':
 272                                 /*
 273                                 ** This used to be...
 274                                 **      _conv(t->tm_hour, 2, ' ');
 275                                 ** ...and has been changed to the below to
 276                                 ** match SunOS 4.1.1 and Arnold Robbin's
 277                                 ** strftime version 3.0. That is, "%k" and
 278                                 ** "%l" have been swapped.
 279                                 ** (ado, 1993-05-24)
 280                                 */
 281                                 pt = _conv((t->tm_hour % 12) ?
 282                                         (t->tm_hour % 12) : 12,
 283                                         "%2d", pt, ptlim);
 284                                 continue;
 285                         case 'M':
 286                                 pt = _conv(t->tm_min, "%02d", pt, ptlim);
 287                                 continue;
 288                         case 'm':
 289                                 pt = _conv(t->tm_mon + 1, "%02d", pt, ptlim);
 290                                 continue;
 291                         case 'n':
 292                                 pt = _add("\n", pt, ptlim);
 293                                 continue;
 294                         case 'p':
 295                                 pt = _add((t->tm_hour >= (HOURSPERDAY / 2)) ?
 296                                         _TIME_LOCALE(loc)->am_pm[1] :
 297                                         _TIME_LOCALE(loc)->am_pm[0],
 298                                         pt, ptlim);
 299                                 continue;
 300                         case 'R':
 301                                 pt = _fmt(sp, "%H:%M", t, pt, ptlim, warnp,
 302                                     loc);
 303                                 continue;
 304                         case 'r':
 305                                 pt = _fmt(sp, _TIME_LOCALE(loc)->t_fmt_ampm, t,
 306                                     pt, ptlim, warnp, loc);
 307                                 continue;
 308                         case 'S':
 309                                 pt = _conv(t->tm_sec, "%02d", pt, ptlim);
 310                                 continue;
 311                         case 's':
 312                                 {
 313                                         struct tm       tm;
 314                                         char            buf[INT_STRLEN_MAXIMUM(
 315                                                                 time_t) + 1];
 316                                         time_t          mkt;
 317
 318                                         tm = *t;
 319                                         mkt = mktime(&tm);
 320                                         /* CONSTCOND */
 321                                         if (TYPE_SIGNED(time_t))
 322                                                 (void)snprintf(buf, sizeof(buf),
 323                                                     "%jd", (intmax_t) mkt);
 324                                         else    (void)snprintf(buf, sizeof(buf),
 325                                                     "%ju", (uintmax_t) mkt);
 326                                         pt = _add(buf, pt, ptlim);
 327                                 }
 328                                 continue;
 329                         case 'T':
 330                                 pt = _fmt(sp, "%H:%M:%S", t, pt, ptlim, warnp,
 331                                     loc);
 332                                 continue;
 333                         case 't':
 334                                 pt = _add("\t", pt, ptlim);
 335                                 continue;
 336                         case 'U':
 337                                 pt = _conv((t->tm_yday + DAYSPERWEEK -
 338                                         t->tm_wday) / DAYSPERWEEK,
 339                                         "%02d", pt, ptlim);
 340                                 continue;
 341                         case 'u':
 342                                 /*
 343                                 ** From Arnold Robbins' strftime version 3.0:
 344                                 ** "ISO 8601: Weekday as a decimal number
 345                                 ** [1 (Monday) - 7]"
 346                                 ** (ado, 1993-05-24)
 347                                 */
 348                                 pt = _conv((t->tm_wday == 0) ?
 349                                         DAYSPERWEEK : t->tm_wday,
 350                                         "%d", pt, ptlim);
 351                                 continue;
 352                         case 'V':       /* ISO 8601 week number */
 353                         case 'G':       /* ISO 8601 year (four digits) */
 354                         case 'g':       /* ISO 8601 year (two digits) */
 355 /*
 356 ** From Arnold Robbins' strftime version 3.0: "the week number of the
 357 ** year (the first Monday as the first day of week 1) as a decimal number
 358 ** (01-53)."
 359 ** (ado, 1993-05-24)
 360 **
 361 ** From <http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html> by Markus Kuhn:
 362 ** "Week 01 of a year is per definition the first week which has the
 363 ** Thursday in this year, which is equivalent to the week which contains
 364 ** the fourth day of January. In other words, the first week of a new year
 365 ** is the week which has the majority of its days in the new year. Week 01
 366 ** might also contain days from the previous year and the week before week
 367 ** 01 of a year is the last week (52 or 53) of the previous year even if
 368 ** it contains days from the new year. A week starts with Monday (day 1)
 369 ** and ends with Sunday (day 7). For example, the first week of the year
 370 ** 1997 lasts from 1996-12-30 to 1997-01-05..."
 371 ** (ado, 1996-01-02)
 372 */
 373                                 {
 374                                         int     year;
 375                                         int     base;
 376                                         int     yday;
 377                                         int     wday;
 378                                         int     w;
 379
 380                                         year = t->tm_year;
 381                                         base = TM_YEAR_BASE;
 382                                         yday = t->tm_yday;
 383                                         wday = t->tm_wday;
 384                                         for ( ; ; ) {
 385                                                 int     len;
 386                                                 int     bot;
 387                                                 int     top;
 388
 389                                                 len = isleap_sum(year, base) ?
 390                                                         DAYSPERLYEAR :
 391                                                         DAYSPERNYEAR;
 392                                                 /*
 393                                                 ** What yday (-3 ... 3) does
 394                                                 ** the ISO year begin on?
 395                                                 */
 396                                                 bot = ((yday + 11 - wday) %
 397                                                         DAYSPERWEEK) - 3;
 398                                                 /*
 399                                                 ** What yday does the NEXT
 400                                                 ** ISO year begin on?
 401                                                 */
 402                                                 top = bot -
 403                                                         (len % DAYSPERWEEK);
 404                                                 if (top < -3)
 405                                                         top += DAYSPERWEEK;
 406                                                 top += len;
 407                                                 if (yday >= top) {
 408                                                         ++base;
 409                                                         w = 1;
 410                                                         break;
 411                                                 }
 412                                                 if (yday >= bot) {
 413                                                         w = 1 + ((yday - bot) /
 414                                                                 DAYSPERWEEK);
 415                                                         break;
 416                                                 }
 417                                                 --base;
 418                                                 yday += isleap_sum(year, base) ?
 419                                                         DAYSPERLYEAR :
 420                                                         DAYSPERNYEAR;
 421                                         }
 422 #ifdef XPG4_1994_04_09
 423                                         if ((w == 52 &&
 424                                                 t->tm_mon == TM_JANUARY) ||
 425                                                 (w == 1 &&
 426                                                 t->tm_mon == TM_DECEMBER))
 427                                                         w = 53;
 428 #endif /* defined XPG4_1994_04_09 */
 429                                         if (*format == 'V')
 430                                                 pt = _conv(w, "%02d",
 431                                                         pt, ptlim);
 432                                         else if (*format == 'g') {
 433                                                 *warnp = IN_ALL;
 434                                                 pt = _yconv(year, base,
 435                                                         false, true,
 436                                                         pt, ptlim);
 437                                         } else  pt = _yconv(year, base,
 438                                                         true, true,
 439                                                         pt, ptlim);
 440                                 }
 441                                 continue;
 442                         case 'v':
 443                                 /*
 444                                 ** From Arnold Robbins' strftime version 3.0:
 445                                 ** "date as dd-bbb-YYYY"
 446                                 ** (ado, 1993-05-24)
 447                                 */
 448                                 pt = _fmt(sp, "%e-%b-%Y", t, pt, ptlim, warnp,
 449                                     loc);
 450                                 continue;
 451                         case 'W':
 452                                 pt = _conv((t->tm_yday + DAYSPERWEEK -
 453                                         (t->tm_wday ?
 454                                         (t->tm_wday - 1) :
 455                                         (DAYSPERWEEK - 1))) / DAYSPERWEEK,
 456                                         "%02d", pt, ptlim);
 457                                 continue;
 458                         case 'w':
 459                                 pt = _conv(t->tm_wday, "%d", pt, ptlim);
 460                                 continue;
 461                         case 'X':
 462                                 pt = _fmt(sp, _TIME_LOCALE(loc)->t_fmt, t, pt,
 463                                     ptlim, warnp, loc);
 464                                 continue;
 465                         case 'x':
 466                                 {
 467                                 int     warn2 = IN_SOME;
 468
 469                                 pt = _fmt(sp, _TIME_LOCALE(loc)->d_fmt, t, pt,
 470                                     ptlim, &warn2, loc);
 471                                 if (warn2 == IN_ALL)
 472                                         warn2 = IN_THIS;
 473                                 if (warn2 > *warnp)
 474                                         *warnp = warn2;
 475                                 }
 476                                 continue;
 477                         case 'y':
 478                                 *warnp = IN_ALL;
 479                                 pt = _yconv(t->tm_year, TM_YEAR_BASE,
 480                                         false, true,
 481                                         pt, ptlim);
 482                                 continue;
 483                         case 'Y':
 484                                 pt = _yconv(t->tm_year, TM_YEAR_BASE,
 485                                         true, true,
 486                                         pt, ptlim);
 487                                 continue;
 488                         case 'Z':
 489 #ifdef TM_ZONE
 490                                 pt = _add(t->TM_ZONE, pt, ptlim);
 491 #endif /* defined TM_ZONE */
 492                                 if (t->tm_isdst >= 0)
 493                                         pt = _add((sp ?
 494                                             tzgetname(sp, t->tm_isdst) :
 495                                             tzname[t->tm_isdst != 0]),
 496                                             pt, ptlim);
 497                                 /*
 498                                 ** C99 says that %Z must be replaced by the
 499                                 ** empty string if the time zone is not
 500                                 ** determinable.
 501                                 */
 502                                 continue;
 503                         case 'z':
 504                                 {
 505                                 long            diff;
 506                                 char const *    sign;
 507
 508                                 if (t->tm_isdst < 0)
 509                                         continue;
 510 #ifdef TM_GMTOFF
 511                                 diff = (int)t->TM_GMTOFF;
 512 #else /* !defined TM_GMTOFF */
 513                                 /*
 514                                 ** C99 says that the UT offset must
 515                                 ** be computed by looking only at
 516                                 ** tm_isdst. This requirement is
 517                                 ** incorrect, since it means the code
 518                                 ** must rely on magic (in this case
 519                                 ** altzone and timezone), and the
 520                                 ** magic might not have the correct
 521                                 ** offset. Doing things correctly is
 522                                 ** tricky and requires disobeying C99;
 523                                 ** see GNU C strftime for details.
 524                                 ** For now, punt and conform to the
 525                                 ** standard, even though it's incorrect.
 526                                 **
 527                                 ** C99 says that %z must be replaced by the
 528                                 ** empty string if the time zone is not
 529                                 ** determinable, so output nothing if the
 530                                 ** appropriate variables are not available.
 531                                 */
 532 #ifndef STD_INSPIRED
 533                                 if (t->tm_isdst == 0)
 534 #ifdef USG_COMPAT
 535                                         diff = -timezone;
 536 #else /* !defined USG_COMPAT */
 537                                         continue;
 538 #endif /* !defined USG_COMPAT */
 539                                 else
 540 #ifdef ALTZONE
 541                                         diff = -altzone;
 542 #else /* !defined ALTZONE */
 543                                         continue;
 544 #endif /* !defined ALTZONE */
 545 #else /* defined STD_INSPIRED */
 546                                 {
 547                                         struct tm tmp;
 548                                         time_t lct, gct;
 549
 550                                         /*
 551                                         ** Get calendar time from t
 552                                         ** being treated as local.
 553                                         */
 554                                         tmp = *t; /* mktime discards const */
 555                                         lct = mktime(&tmp);
 556
 557                                         if (lct == (time_t)-1)
 558                                                 continue;
 559
 560                                         /*
 561                                         ** Get calendar time from t
 562                                         ** being treated as GMT.
 563                                         **/
 564                                         tmp = *t; /* mktime discards const */
 565                                         gct = timegm(&tmp);
 566
 567                                         if (gct == (time_t)-1)
 568                                                 continue;
 569
 570                                         /* LINTED difference will fit int */
 571                                         diff = (intmax_t)gct - (intmax_t)lct;
 572                                 }
 573 #endif /* defined STD_INSPIRED */
 574 #endif /* !defined TM_GMTOFF */
 575                                 if (diff < 0) {
 576                                         sign = "-";
 577                                         diff = -diff;
 578                                 } else  sign = "+";
 579                                 pt = _add(sign, pt, ptlim);
 580                                 diff /= SECSPERMIN;
 581                                 diff = (diff / MINSPERHOUR) * 100 +
 582                                         (diff % MINSPERHOUR);
 583                                 _DIAGASSERT(__type_fit(int, diff));
 584                                 pt = _conv((int)diff, "%04d", pt, ptlim);
 585                                 }
 586                                 continue;
 587 #if defined(__minix)
 588                         case '+':
 589                                 pt = _fmt(sp, _TIME_LOCALE(loc)->c_fmt, t, pt, ptlim, warnp, loc);
 590                                 continue;
 591 #endif /* defined(__minix) */
 592 #if 0
 593                         case '+':
 594                                 pt = _fmt(sp, _TIME_LOCALE(loc)->date_fmt, t,
 595                                     pt, ptlim, warnp, loc);
 596                                 continue;
 597 #endif
 598                         case '%':
 599                         /*
 600                         ** X311J/88-090 (4.12.3.5): if conversion char is
 601                         ** undefined, behavior is undefined. Print out the
 602                         ** character itself as printf(3) also does.
 603                         */
 604                         default:
 605                                 break;
 606                         }
 607                 }
 608                 if (pt == ptlim)
 609                         break;
 610                 *pt++ = *format;
 611         }
 612         return pt;
 613 }
 614
 615 size_t
 616 strftime(char *s, size_t maxsize, const char *format, const struct tm *t)
 617 {
 618         tzset();
 619         return strftime_z(NULL, s, maxsize, format, t);
 620 }
 621
 622 size_t
 623 strftime_l(char * __restrict s, size_t maxsize, const char * __restrict format,
 624     const struct tm * __restrict t, locale_t loc)
 625 {
 626         tzset();
 627         return strftime_lz(NULL, s, maxsize, format, t, loc);
 628 }
 629
 630 static char *
 631 _conv(int n, const char *format, char *pt, const char *ptlim)
 632 {
 633         char    buf[INT_STRLEN_MAXIMUM(int) + 1];
 634
 635         (void) snprintf(buf, sizeof(buf), format, n);
 636         return _add(buf, pt, ptlim);
 637 }
 638
 639 static char *
 640 _add(const char *str, char *pt, const char *ptlim)
 641 {
 642         while (pt < ptlim && (*pt = *str++) != '\0')
 643                 ++pt;
 644         return pt;
 645 }
 646
 647 /*
 648 ** POSIX and the C Standard are unclear or inconsistent about
 649 ** what %C and %y do if the year is negative or exceeds 9999.
 650 ** Use the convention that %C concatenated with %y yields the
 651 ** same output as %Y, and that %Y contains at least 4 bytes,
 652 ** with more only if necessary.
 653 */
 654
 655 static char *
 656 _yconv(int a, int b, bool convert_top, bool convert_yy,
 657     char *pt, const char * ptlim)
 658 {
 659         int     lead;
 660         int     trail;
 661
 662 #define DIVISOR 100
 663         trail = a % DIVISOR + b % DIVISOR;
 664         lead = a / DIVISOR + b / DIVISOR + trail / DIVISOR;
 665         trail %= DIVISOR;
 666         if (trail < 0 && lead > 0) {
 667                 trail += DIVISOR;
 668                 --lead;
 669         } else if (lead < 0 && trail > 0) {
 670                 trail -= DIVISOR;
 671                 ++lead;
 672         }
 673         if (convert_top) {
 674                 if (lead == 0 && trail < 0)
 675                         pt = _add("-0", pt, ptlim);
 676                 else    pt = _conv(lead, "%02d", pt, ptlim);
 677         }
 678         if (convert_yy)
 679                 pt = _conv(((trail < 0) ? -trail : trail), "%02d", pt, ptlim);
 680         return pt;
 681 }