usr/src/lib/libc/port/locale/strftime.c

   1 /*
   2  * Copyright 2013 Garrett D'Amore <garrett@damore.org>
   3  * Copyright 2010 Nexenta Systems, Inc.  All rights reserved.
   4  * Copyright (c) 1989 The Regents of the University of California.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms are permitted
   8  * provided that the above copyright notice and this paragraph are
   9  * duplicated in all such forms and that any documentation,
  10  * advertising materials, and other materials related to such
  11  * distribution and use acknowledge that the software was developed
  12  * by the University of California, Berkeley. The name of the
  13  * University may not be used to endorse or promote products derived
  14  * from this software without specific prior written permission.
  15  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  17  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  18  */
  19
  20 #include "lint.h"
  21 #include "tzfile.h"
  22 #include <fcntl.h>
  23 #include <sys/stat.h>
  24 #include <string.h>
  25 #include <stdio.h>
  26 #include <locale.h>
  27 #include "timelocal.h"
  28 #include "localeimpl.h"
  29
  30 static char *_add(const char *, char *, const char *);
  31 static char *_conv(int, const char *, char *, const char *);
  32 static char *_fmt(locale_t, const char *, const struct tm *, char *,
  33     const char * const);
  34 static char *_yconv(int, int, int, int, char *, const char *);
  35
  36 extern char *tzname[];
  37
  38 #define IN_NONE 0
  39 #define IN_SOME 1
  40 #define IN_THIS 2
  41 #define IN_ALL  3
  42
  43 #define PAD_DEFAULT     0
  44 #define PAD_LESS        1
  45 #define PAD_SPACE       2
  46 #define PAD_ZERO        3
  47
  48 static const char *fmt_padding[][4] = {
  49         /* DEFAULT,     LESS,   SPACE,  ZERO */
  50 #define PAD_FMT_MONTHDAY        0
  51 #define PAD_FMT_HMS             0
  52 #define PAD_FMT_CENTURY         0
  53 #define PAD_FMT_SHORTYEAR       0
  54 #define PAD_FMT_MONTH           0
  55 #define PAD_FMT_WEEKOFYEAR      0
  56 #define PAD_FMT_DAYOFMONTH      0
  57         { "%02d",       "%d",   "%2d",  "%02d" },
  58 #define PAD_FMT_SDAYOFMONTH     1
  59 #define PAD_FMT_SHMS            1
  60         { "%2d",        "%d",   "%2d",  "%02d" },
  61 #define PAD_FMT_DAYOFYEAR       2
  62         { "%03d",       "%d",   "%3d",  "%03d" },
  63 #define PAD_FMT_YEAR            3
  64         { "%04d",       "%d",   "%4d",  "%04d" }
  65 };
  66
  67
  68 size_t
  69 strftime_l(char *_RESTRICT_KYWD s, size_t maxsize,
  70     const char *_RESTRICT_KYWD format, const struct tm *_RESTRICT_KYWD t,
  71     locale_t loc)
  72 {
  73         char *p;
  74
  75         tzset();
  76         p = _fmt(loc, ((format == NULL) ? "%c" : format), t, s, s + maxsize);
  77         if (p == s + maxsize)
  78                 return (0);
  79         *p = '\0';
  80         return (p - s);
  81 }
  82
  83 size_t
  84 strftime(char *_RESTRICT_KYWD s, size_t maxsize,
  85     const char *_RESTRICT_KYWD format, const struct tm *_RESTRICT_KYWD t)
  86 {
  87         return (strftime_l(s, maxsize, format, t, uselocale(NULL)));
  88 }
  89
  90 static char *
  91 _fmt(locale_t loc, const char *format, const struct tm *t, char *pt,
  92     const char * const ptlim)
  93 {
  94         int Ealternative, Oalternative, PadIndex;
  95         const struct lc_time *tptr = loc->time;
  96
  97 #define PADDING(x)      fmt_padding[x][PadIndex]
  98
  99         for (; *format; ++format) {
 100                 if (*format == '%') {
 101                         Ealternative = 0;
 102                         Oalternative = 0;
 103                         PadIndex         = PAD_DEFAULT;
 104 label:
 105                         switch (*++format) {
 106                         case '\0':
 107                                 --format;
 108                                 break;
 109                         case 'A':
 110                                 pt = _add((t->tm_wday < 0 ||
 111                                     t->tm_wday >= DAYSPERWEEK) ?
 112                                     "?" : tptr->weekday[t->tm_wday],
 113                                     pt, ptlim);
 114                                 continue;
 115                         case 'a':
 116                                 pt = _add((t->tm_wday < 0 ||
 117                                     t->tm_wday >= DAYSPERWEEK) ?
 118                                     "?" : tptr->wday[t->tm_wday],
 119                                     pt, ptlim);
 120                                 continue;
 121                         case 'B':
 122                                 pt = _add((t->tm_mon < 0 ||
 123                                     t->tm_mon >= MONSPERYEAR) ?
 124                                     "?" : (tptr->month)[t->tm_mon],
 125                                     pt, ptlim);
 126                                 continue;
 127                         case 'b':
 128                         case 'h':
 129                                 pt = _add((t->tm_mon < 0 ||
 130                                     t->tm_mon >= MONSPERYEAR) ?
 131                                     "?" : tptr->mon[t->tm_mon],
 132                                     pt, ptlim);
 133                                 continue;
 134                         case 'C':
 135                                 /*
 136                                  * %C used to do a...
 137                                  *      _fmt("%a %b %e %X %Y", t);
 138                                  * ...whereas now POSIX 1003.2 calls for
 139                                  * something completely different.
 140                                  * (ado, 1993-05-24)
 141                                  */
 142                                 pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 0,
 143                                     pt, ptlim);
 144                                 continue;
 145                         case 'c':
 146                                 pt = _fmt(loc, tptr->c_fmt, t, pt, ptlim);
 147                                 continue;
 148                         case 'D':
 149                                 pt = _fmt(loc, "%m/%d/%y", t, pt, ptlim);
 150                                 continue;
 151                         case 'd':
 152                                 pt = _conv(t->tm_mday,
 153                                     PADDING(PAD_FMT_DAYOFMONTH), pt, ptlim);
 154                                 continue;
 155                         case 'E':
 156                                 if (Ealternative || Oalternative)
 157                                         break;
 158                                 Ealternative++;
 159                                 goto label;
 160                         case 'O':
 161                                 /*
 162                                  * C99 locale modifiers.
 163                                  * The sequences
 164                                  *      %Ec %EC %Ex %EX %Ey %EY
 165                                  *      %Od %oe %OH %OI %Om %OM
 166                                  *      %OS %Ou %OU %OV %Ow %OW %Oy
 167                                  * are supposed to provide alternate
 168                                  * representations.
 169                                  */
 170                                 if (Ealternative || Oalternative)
 171                                         break;
 172                                 Oalternative++;
 173                                 goto label;
 174                         case 'e':
 175                                 pt = _conv(t->tm_mday,
 176                                     PADDING(PAD_FMT_SDAYOFMONTH), pt, ptlim);
 177                                 continue;
 178                         case 'F':
 179                                 pt = _fmt(loc, "%Y-%m-%d", t, pt, ptlim);
 180                                 continue;
 181                         case 'H':
 182                                 pt = _conv(t->tm_hour, PADDING(PAD_FMT_HMS),
 183                                     pt, ptlim);
 184                                 continue;
 185                         case 'I':
 186                                 pt = _conv((t->tm_hour % 12) ?
 187                                     (t->tm_hour % 12) : 12,
 188                                     PADDING(PAD_FMT_HMS), pt, ptlim);
 189                                 continue;
 190                         case 'j':
 191                                 pt = _conv(t->tm_yday + 1,
 192                                     PADDING(PAD_FMT_DAYOFYEAR), pt, ptlim);
 193                                 continue;
 194                         case 'k':
 195                                 /*
 196                                  * This used to be...
 197                                  *      _conv(t->tm_hour % 12 ?
 198                                  *              t->tm_hour % 12 : 12, 2, ' ');
 199                                  * ...and has been changed to the below to
 200                                  * match SunOS 4.1.1 and Arnold Robbins'
 201                                  * strftime version 3.0. That is, "%k" and
 202                                  * "%l" have been swapped.
 203                                  * (ado, 1993-05-24)
 204                                  */
 205                                 pt = _conv(t->tm_hour,
 206                                     PADDING(PAD_FMT_SHMS), pt, ptlim);
 207                                 continue;
 208                         case 'l':
 209                                 /*
 210                                  * This used to be...
 211                                  *      _conv(t->tm_hour, 2, ' ');
 212                                  * ...and has been changed to the below to
 213                                  * match SunOS 4.1.1 and Arnold Robbin's
 214                                  * strftime version 3.0. That is, "%k" and
 215                                  * "%l" have been swapped.
 216                                  * (ado, 1993-05-24)
 217                                  */
 218                                 pt = _conv((t->tm_hour % 12) ?
 219                                     (t->tm_hour % 12) : 12,
 220                                     PADDING(PAD_FMT_SHMS), pt, ptlim);
 221                                 continue;
 222                         case 'M':
 223                                 pt = _conv(t->tm_min, PADDING(PAD_FMT_HMS),
 224                                     pt, ptlim);
 225                                 continue;
 226                         case 'm':
 227                                 pt = _conv(t->tm_mon + 1,
 228                                     PADDING(PAD_FMT_MONTH),
 229                                     pt, ptlim);
 230                                 continue;
 231                         case 'n':
 232                                 pt = _add("\n", pt, ptlim);
 233                                 continue;
 234                         case 'p':
 235                                 pt = _add((t->tm_hour >= (HOURSPERDAY / 2)) ?
 236                                     tptr->pm : tptr->am, pt, ptlim);
 237                                 continue;
 238                         case 'R':
 239                                 pt = _fmt(loc, "%H:%M", t, pt, ptlim);
 240                                 continue;
 241                         case 'r':
 242                                 pt = _fmt(loc, tptr->ampm_fmt, t, pt, ptlim);
 243                                 continue;
 244                         case 'S':
 245                                 pt = _conv(t->tm_sec, PADDING(PAD_FMT_HMS),
 246                                     pt, ptlim);
 247                                 continue;
 248
 249                         case 's':
 250                         {
 251                                 struct tm tm;
 252                                 char *buf;
 253
 254                                 tm = *t;
 255                                 (void) asprintf(&buf, "%ld", mktime(&tm));
 256                                 pt = _add(buf, pt, ptlim);
 257                                 continue;
 258                         }
 259
 260                         case 'T':
 261                                 pt = _fmt(loc, "%H:%M:%S", t, pt, ptlim);
 262                                 continue;
 263                         case 't':
 264                                 pt = _add("\t", pt, ptlim);
 265                                 continue;
 266                         case 'U':
 267                                 pt = _conv((t->tm_yday + DAYSPERWEEK -
 268                                     t->tm_wday) / DAYSPERWEEK,
 269                                     PADDING(PAD_FMT_WEEKOFYEAR),
 270                                     pt, ptlim);
 271                                 continue;
 272                         case 'u':
 273                                 /*
 274                                  * From Arnold Robbins' strftime version 3.0:
 275                                  * "ISO 8601: Weekday as a decimal number
 276                                  * [1 (Monday) - 7]"
 277                                  * (ado, 1993-05-24)
 278                                  */
 279                                 pt = _conv((t->tm_wday == 0) ?
 280                                     DAYSPERWEEK : t->tm_wday,
 281                                     "%d", pt, ptlim);
 282                                 continue;
 283                         case 'V':       /* ISO 8601 week number */
 284                         case 'G':       /* ISO 8601 year (four digits) */
 285                         case 'g':       /* ISO 8601 year (two digits) */
 286 /*
 287  * From Arnold Robbins' strftime version 3.0: "the week number of the
 288  * year (the first Monday as the first day of week 1) as a decimal number
 289  * (01-53)."
 290  * (ado, 1993-05-24)
 291  *
 292  * From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn:
 293  * "Week 01 of a year is per definition the first week which has the
 294  * Thursday in this year, which is equivalent to the week which contains
 295  * the fourth day of January. In other words, the first week of a new year
 296  * is the week which has the majority of its days in the new year. Week 01
 297  * might also contain days from the previous year and the week before week
 298  * 01 of a year is the last week (52 or 53) of the previous year even if
 299  * it contains days from the new year. A week starts with Monday (day 1)
 300  * and ends with Sunday (day 7). For example, the first week of the year
 301  * 1997 lasts from 1996-12-30 to 1997-01-05..."
 302  * (ado, 1996-01-02)
 303  */
 304                         {
 305                                 int     year;
 306                                 int     base;
 307                                 int     yday;
 308                                 int     wday;
 309                                 int     w;
 310
 311                                 year = t->tm_year;
 312                                 base = TM_YEAR_BASE;
 313                                 yday = t->tm_yday;
 314                                 wday = t->tm_wday;
 315                                 for (;;) {
 316                                         int     len;
 317                                         int     bot;
 318                                         int     top;
 319
 320                                         len = isleap_sum(year, base) ?
 321                                             DAYSPERLYEAR : DAYSPERNYEAR;
 322                                         /*
 323                                          * What yday (-3 ... 3) does
 324                                          * the ISO year begin on?
 325                                          */
 326                                         bot = ((yday + 11 - wday) %
 327                                             DAYSPERWEEK) - 3;
 328                                         /*
 329                                          * What yday does the NEXT
 330                                          * ISO year begin on?
 331                                          */
 332                                         top = bot - (len % DAYSPERWEEK);
 333                                         if (top < -3)
 334                                                 top += DAYSPERWEEK;
 335                                         top += len;
 336                                         if (yday >= top) {
 337                                                 ++base;
 338                                                 w = 1;
 339                                                 break;
 340                                         }
 341                                         if (yday >= bot) {
 342                                                 w = 1 + ((yday - bot) /
 343                                                     DAYSPERWEEK);
 344                                                 break;
 345                                         }
 346                                         --base;
 347                                         yday += isleap_sum(year, base) ?
 348                                             DAYSPERLYEAR : DAYSPERNYEAR;
 349                                 }
 350 #ifdef XPG4_1994_04_09
 351                                 if ((w == 52 && t->tm_mon == TM_JANUARY) ||
 352                                     (w == 1 && t->tm_mon == TM_DECEMBER))
 353                                         w = 53;
 354 #endif /* defined XPG4_1994_04_09 */
 355                                 if (*format == 'V')
 356                                         pt = _conv(w,
 357                                             PADDING(PAD_FMT_WEEKOFYEAR),
 358                                             pt, ptlim);
 359                                 else if (*format == 'g') {
 360                                         pt = _yconv(year, base, 0, 1,
 361                                             pt, ptlim);
 362                                 } else
 363                                         pt = _yconv(year, base, 1, 1,
 364                                             pt, ptlim);
 365                         }
 366                                 continue;
 367                         case 'v':
 368                                 /*
 369                                  * From Arnold Robbins' strftime version 3.0:
 370                                  * "date as dd-bbb-YYYY"
 371                                  * (ado, 1993-05-24)
 372                                  */
 373                                 pt = _fmt(loc, "%e-%b-%Y", t, pt, ptlim);
 374                                 continue;
 375                         case 'W':
 376                                 pt = _conv((t->tm_yday + DAYSPERWEEK -
 377                                     (t->tm_wday ?
 378                                     (t->tm_wday - 1) :
 379                                     (DAYSPERWEEK - 1))) / DAYSPERWEEK,
 380                                     PADDING(PAD_FMT_WEEKOFYEAR),
 381                                     pt, ptlim);
 382                                 continue;
 383                         case 'w':
 384                                 pt = _conv(t->tm_wday, "%d", pt, ptlim);
 385                                 continue;
 386                         case 'X':
 387                                 pt = _fmt(loc, tptr->X_fmt, t, pt, ptlim);
 388                                 continue;
 389                         case 'x':
 390                                 pt = _fmt(loc, tptr->x_fmt, t, pt, ptlim);
 391                                 continue;
 392                         case 'y':
 393                                 pt = _yconv(t->tm_year, TM_YEAR_BASE, 0, 1,
 394                                     pt, ptlim);
 395                                 continue;
 396                         case 'Y':
 397                                 pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 1,
 398                                     pt, ptlim);
 399                                 continue;
 400                         case 'Z':
 401                                 if (t->tm_isdst >= 0)
 402                                         pt = _add(tzname[t->tm_isdst != 0],
 403                                             pt, ptlim);
 404                                 /*
 405                                  * C99 says that %Z must be replaced by the
 406                                  * empty string if the time zone is not
 407                                  * determinable.
 408                                  */
 409                                 continue;
 410                         case 'z':
 411                                 {
 412                                 int             diff;
 413                                 char const *    sign;
 414
 415                                 if (t->tm_isdst < 0)
 416                                         continue;
 417                                 /*
 418                                  * C99 says that the UTC offset must
 419                                  * be computed by looking only at
 420                                  * tm_isdst. This requirement is
 421                                  * incorrect, since it means the code
 422                                  * must rely on magic (in this case
 423                                  * altzone and timezone), and the
 424                                  * magic might not have the correct
 425                                  * offset. Doing things correctly is
 426                                  * tricky and requires disobeying C99;
 427                                  * see GNU C strftime for details.
 428                                  * For now, punt and conform to the
 429                                  * standard, even though it's incorrect.
 430                                  *
 431                                  * C99 says that %z must be replaced by the
 432                                  * empty string if the time zone is not
 433                                  * determinable, so output nothing if the
 434                                  * appropriate variables are not available.
 435                                  */
 436                                 if (t->tm_isdst == 0)
 437                                         diff = -timezone;
 438                                 else
 439                                         diff = -altzone;
 440                                 if (diff < 0) {
 441                                         sign = "-";
 442                                         diff = -diff;
 443                                 } else
 444                                         sign = "+";
 445                                 pt = _add(sign, pt, ptlim);
 446                                 diff /= SECSPERMIN;
 447                                 diff = (diff / MINSPERHOUR) * 100 +
 448                                     (diff % MINSPERHOUR);
 449                                 pt = _conv(diff, PADDING(PAD_FMT_YEAR),
 450                                     pt, ptlim);
 451                                 }
 452                                 continue;
 453                         case '+':
 454                                 pt = _fmt(loc, tptr->date_fmt, t, pt, ptlim);
 455                                 continue;
 456                         case '-':
 457                                 if (PadIndex != PAD_DEFAULT)
 458                                         break;
 459                                 PadIndex = PAD_LESS;
 460                                 goto label;
 461                         case '_':
 462                                 if (PadIndex != PAD_DEFAULT)
 463                                         break;
 464                                 PadIndex = PAD_SPACE;
 465                                 goto label;
 466                         case '0':
 467                                 if (PadIndex != PAD_DEFAULT)
 468                                         break;
 469                                 PadIndex = PAD_ZERO;
 470                                 goto label;
 471                         case '%':
 472                         /*
 473                          * X311J/88-090 (4.12.3.5): if conversion char is
 474                          * undefined, behavior is undefined. Print out the
 475                          * character itself as printf(3) also does.
 476                          */
 477                         default:
 478                                 break;
 479                         }
 480                 }
 481                 if (pt == ptlim)
 482                         break;
 483                 *pt++ = *format;
 484         }
 485         return (pt);
 486 }
 487
 488 static char *
 489 _conv(const int n, const char *format, char *const pt,
 490     const char *const ptlim)
 491 {
 492         char    buf[12];
 493
 494         (void) sprintf(buf, format, n);
 495         return (_add(buf, pt, ptlim));
 496 }
 497
 498 static char *
 499 _add(const char *str, char *pt, const char *const ptlim)
 500 {
 501         while (pt < ptlim && (*pt = *str++) != '\0')
 502                 ++pt;
 503         return (pt);
 504 }
 505
 506 /*
 507  * POSIX and the C Standard are unclear or inconsistent about
 508  * what %C and %y do if the year is negative or exceeds 9999.
 509  * Use the convention that %C concatenated with %y yields the
 510  * same output as %Y, and that %Y contains at least 4 bytes,
 511  * with more only if necessary.
 512  */
 513
 514 static char *
 515 _yconv(const int a, const int b, const int convert_top, const int convert_yy,
 516     char *pt, const char * const ptlim)
 517 {
 518         register int    lead;
 519         register int    trail;
 520
 521 #define DIVISOR 100
 522         trail = a % DIVISOR + b % DIVISOR;
 523         lead = a / DIVISOR + b / DIVISOR + trail / DIVISOR;
 524         trail %= DIVISOR;
 525         if (trail < 0 && lead > 0) {
 526                 trail += DIVISOR;
 527                 --lead;
 528         } else if (lead < 0 && trail > 0) {
 529                 trail -= DIVISOR;
 530                 ++lead;
 531         }
 532         if (convert_top) {
 533                 if (lead == 0 && trail < 0)
 534                         pt = _add("-0", pt, ptlim);
 535                 else    pt = _conv(lead, "%02d", pt, ptlim);
 536         }
 537         if (convert_yy)
 538                 pt = _conv(((trail < 0) ? -trail : trail), "%02d", pt, ptlim);
 539         return (pt);
 540 }