strftime.c revision 1.57
1 /* $NetBSD: strftime.c,v 1.57 2025/01/23 22:44:22 christos Exp $ */ 2 3 /* Convert a broken-down timestamp to a string. */ 4 5 /* Copyright 1989 The Regents of the University of California. 6 All rights reserved. 7 8 Redistribution and use in source and binary forms, with or without 9 modification, are permitted provided that the following conditions 10 are met: 11 1. Redistributions of source code must retain the above copyright 12 notice, this list of conditions and the following disclaimer. 13 2. Redistributions in binary form must reproduce the above copyright 14 notice, this list of conditions and the following disclaimer in the 15 documentation and/or other materials provided with the distribution. 16 3. Neither the name of the University nor the names of its contributors 17 may be used to endorse or promote products derived from this software 18 without specific prior written permission. 19 20 THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS" AND 21 ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 SUCH DAMAGE. */ 31 32 #include <sys/cdefs.h> 33 #if defined(LIBC_SCCS) && !defined(lint) 34 #if 0 35 static char elsieid[] = "@(#)strftime.c 7.64"; 36 static char elsieid[] = "@(#)strftime.c 8.3"; 37 #else 38 __RCSID("$NetBSD: strftime.c,v 1.57 2025/01/23 22:44:22 christos Exp $"); 39 #endif 40 #endif /* LIBC_SCCS and not lint */ 41 42 #include "namespace.h" 43 44 #include <stddef.h> 45 #include <assert.h> 46 #include <locale.h> 47 #include "setlocale_local.h" 48 49 /* 50 ** Based on the UCB version with the copyright notice appearing above. 51 ** 52 ** This is ANSIish only when "multibyte character == plain character". 53 */ 54 55 #include "private.h" 56 57 /* 58 ** We don't use these extensions in strftime operation even when 59 ** supported by the local tzcode configuration. A strictly 60 ** conforming C application may leave them in undefined state. 61 */ 62 63 #ifdef _LIBC 64 #undef TM_ZONE 65 #undef TM_GMTOFF 66 #endif 67 68 #include <fcntl.h> 69 #include <locale.h> 70 #include <stdio.h> 71 72 /* If true, the value returned by an idealized unlimited-range mktime 73 always fits into an integer type with bounds MIN and MAX. 74 If false, the value might not fit. 75 This macro is usable in #if if its arguments are. 76 Add or subtract 2**31 - 1 for the maximum UT offset allowed in a TZif file, 77 divide by the maximum number of non-leap seconds in a year, 78 divide again by two just to be safe, 79 and account for the tm_year origin (1900) and time_t origin (1970). */ 80 #define MKTIME_FITS_IN(min, max) \ 81 ((min) < 0 \ 82 && ((min) + 0x7fffffff) / 366 / 24 / 60 / 60 / 2 + 1970 - 1900 < INT_MIN \ 83 && INT_MAX < ((max) - 0x7fffffff) / 366 / 24 / 60 / 60 / 2 + 1970 - 1900) 84 85 /* MKTIME_MIGHT_OVERFLOW is true if mktime can fail due to time_t overflow 86 or if it is not known whether mktime can fail, 87 and is false if mktime definitely cannot fail. 88 This macro is usable in #if, and so does not use TIME_T_MAX or sizeof. 89 If the builder has not configured this macro, guess based on what 90 known platforms do. When in doubt, guess true. */ 91 #ifndef MKTIME_MIGHT_OVERFLOW 92 # if defined __FreeBSD__ || defined __NetBSD__ || defined __OpenBSD__ 93 # include <sys/param.h> 94 # endif 95 # if ((/* The following heuristics assume native time_t. */ \ 96 defined_time_tz) \ 97 || ((/* Traditional time_t is 'long', so if 'long' is not wide enough \ 98 assume overflow unless we're on a known-safe host. */ \ 99 !MKTIME_FITS_IN(LONG_MIN, LONG_MAX)) \ 100 && (/* GNU C Library 2.29 (2019-02-01) and later has 64-bit time_t \ 101 if __TIMESIZE is 64. */ \ 102 !defined __TIMESIZE || __TIMESIZE < 64) \ 103 && (/* FreeBSD 12 r320347 (__FreeBSD_version 1200036; 2017-06-26), \ 104 and later has 64-bit time_t on all platforms but i386 which \ 105 is currently scheduled for end-of-life on 2028-11-30. */ \ 106 !defined __FreeBSD_version || __FreeBSD_version < 1200036 \ 107 || defined __i386) \ 108 && (/* NetBSD 6.0 (2012-10-17) and later has 64-bit time_t. */ \ 109 !defined __NetBSD_Version__ || __NetBSD_Version__ < 600000000) \ 110 && (/* OpenBSD 5.5 (2014-05-01) and later has 64-bit time_t. */ \ 111 !defined OpenBSD || OpenBSD < 201405))) 112 # define MKTIME_MIGHT_OVERFLOW 1 113 # else 114 # define MKTIME_MIGHT_OVERFLOW 0 115 # endif 116 #endif 117 /* Check that MKTIME_MIGHT_OVERFLOW is consistent with time_t's range. */ 118 static_assert(MKTIME_MIGHT_OVERFLOW 119 || MKTIME_FITS_IN(TIME_T_MIN, TIME_T_MAX)); 120 121 #if MKTIME_MIGHT_OVERFLOW 122 /* Do this after system includes as it redefines time_t, mktime, timeoff. */ 123 # define USE_TIMEX_T true 124 # include "localtime.c" 125 #endif 126 127 #ifndef DEPRECATE_TWO_DIGIT_YEARS 128 # define DEPRECATE_TWO_DIGIT_YEARS 0 129 #endif 130 131 #ifdef __weak_alias 132 __weak_alias(strftime_l, _strftime_l) 133 __weak_alias(strftime_lz, _strftime_lz) 134 __weak_alias(strftime_z, _strftime_z) 135 #endif 136 137 #include "sys/localedef.h" 138 #define _TIME_LOCALE(loc) \ 139 ((_TimeLocale *)((loc)->part_impl[LC_TIME])) 140 #define c_fmt d_t_fmt 141 142 enum warn { IN_NONE, IN_SOME, IN_THIS, IN_ALL }; 143 144 static char * _add(const char *, char *, const char *); 145 static char * _conv(int, const char *, char *, const char *, locale_t); 146 static char * _fmt(const timezone_t, const char *, const struct tm *, char *, 147 const char *, enum warn *, locale_t); 148 static char * _yconv(int, int, bool, bool, char *, const char *, locale_t); 149 150 #ifndef YEAR_2000_NAME 151 # define YEAR_2000_NAME "CHECK_STRFTIME_FORMATS_FOR_TWO_DIGIT_YEARS" 152 #endif /* !defined YEAR_2000_NAME */ 153 154 #define IN_NONE 0 155 #define IN_SOME 1 156 #define IN_THIS 2 157 #define IN_ALL 3 158 159 #define PAD_DEFAULT 0 160 #define PAD_LESS 1 161 #define PAD_SPACE 2 162 #define PAD_ZERO 3 163 164 static const char fmt_padding[][4][5] = { 165 /* DEFAULT, LESS, SPACE, ZERO */ 166 #define PAD_FMT_MONTHDAY 0 167 #define PAD_FMT_HMS 0 168 #define PAD_FMT_CENTURY 0 169 #define PAD_FMT_SHORTYEAR 0 170 #define PAD_FMT_MONTH 0 171 #define PAD_FMT_WEEKOFYEAR 0 172 #define PAD_FMT_DAYOFMONTH 0 173 { "%02d", "%d", "%2d", "%02d" }, 174 #define PAD_FMT_SDAYOFMONTH 1 175 #define PAD_FMT_SHMS 1 176 { "%2d", "%d", "%2d", "%02d" }, 177 #define PAD_FMT_DAYOFYEAR 2 178 { "%03d", "%d", "%3d", "%03d" }, 179 #define PAD_FMT_YEAR 3 180 { "%04d", "%d", "%4d", "%04d" } 181 }; 182 183 size_t 184 strftime_z(const timezone_t sp, char * __restrict s, size_t maxsize, 185 const char * __restrict format, const struct tm * __restrict t) 186 { 187 return strftime_lz(sp, s, maxsize, format, t, _current_locale()); 188 } 189 190 #if HAVE_STRFTIME_L 191 size_t 192 strftime_l(char *restrict s, size_t maxsize, char const *restrict format, 193 struct tm const *restrict t, 194 ATTRIBUTE_MAYBE_UNUSED locale_t locale) 195 { 196 /* Just call strftime, as only the C locale is supported. */ 197 return strftime(s, maxsize, format, t); 198 } 199 #endif 200 201 size_t 202 strftime_lz(const timezone_t sp, char *const s, const size_t maxsize, 203 const char *const format, const struct tm *const t, locale_t loc) 204 { 205 char * p; 206 int saved_errno = errno; 207 enum warn warn = IN_NONE; 208 209 p = _fmt(sp, format, t, s, s + maxsize, &warn, loc); 210 if (/*CONSTCOND*/DEPRECATE_TWO_DIGIT_YEARS 211 && warn != IN_NONE && getenv(YEAR_2000_NAME)) { 212 (void) fprintf(stderr, "\n"); 213 (void) fprintf(stderr, "strftime format \"%s\" ", format); 214 (void) fprintf(stderr, "yields only two digits of years in "); 215 if (warn == IN_SOME) 216 (void) fprintf(stderr, "some locales"); 217 else if (warn == IN_THIS) 218 (void) fprintf(stderr, "the current locale"); 219 else (void) fprintf(stderr, "all locales"); 220 (void) fprintf(stderr, "\n"); 221 } 222 if (p == s + maxsize) { 223 errno = ERANGE; 224 return 0; 225 } 226 *p = '\0'; 227 errno = saved_errno; 228 return p - s; 229 } 230 231 static char * 232 _fmt(const timezone_t sp, const char *format, const struct tm *t, char *pt, 233 const char *ptlim, enum warn *warnp, locale_t loc) 234 { 235 int Ealternative, Oalternative, PadIndex; 236 _TimeLocale *tptr = _TIME_LOCALE(loc); 237 238 for ( ; *format; ++format) { 239 if (*format == '%') { 240 Ealternative = 0; 241 Oalternative = 0; 242 PadIndex = PAD_DEFAULT; 243 label: 244 switch (*++format) { 245 case '\0': 246 /* Output unknown conversion specifiers as-is, 247 to aid debugging. This includes '%' at 248 format end. This conforms to C23 section 249 7.29.3.5 paragraph 6, which says behavior 250 is undefined here. */ 251 default: 252 --format; 253 break; 254 case 'A': 255 pt = _add((t->tm_wday < 0 || 256 t->tm_wday >= DAYSPERWEEK) ? 257 "?" : tptr->day[t->tm_wday], 258 pt, ptlim); 259 continue; 260 case 'a': 261 pt = _add((t->tm_wday < 0 || 262 t->tm_wday >= DAYSPERWEEK) ? 263 "?" : tptr->abday[t->tm_wday], 264 pt, ptlim); 265 continue; 266 case 'B': 267 pt = _add((t->tm_mon < 0 || 268 t->tm_mon >= MONSPERYEAR) ? 269 "?" : 270 /* no alt_month in _TimeLocale */ 271 (Oalternative ? tptr->mon/*alt_month*/: 272 tptr->mon)[t->tm_mon], 273 pt, ptlim); 274 continue; 275 case 'b': 276 case 'h': 277 pt = _add((t->tm_mon < 0 || 278 t->tm_mon >= MONSPERYEAR) ? 279 "?" : tptr->abmon[t->tm_mon], 280 pt, ptlim); 281 continue; 282 case 'C': 283 /* 284 ** %C used to do a... 285 ** _fmt("%a %b %e %X %Y", t); 286 ** ...whereas now POSIX 1003.2 calls for 287 ** something completely different. 288 ** (ado, 1993-05-24) 289 */ 290 pt = _yconv(t->tm_year, TM_YEAR_BASE, 291 true, false, pt, ptlim, loc); 292 continue; 293 case 'c': 294 { 295 enum warn warn2 = IN_SOME; 296 297 pt = _fmt(sp, tptr->c_fmt, t, pt, 298 ptlim, &warn2, loc); 299 if (warn2 == IN_ALL) 300 warn2 = IN_THIS; 301 if (warn2 > *warnp) 302 *warnp = warn2; 303 } 304 continue; 305 case 'D': 306 pt = _fmt(sp, "%m/%d/%y", t, pt, ptlim, warnp, 307 loc); 308 continue; 309 case 'd': 310 pt = _conv(t->tm_mday, 311 fmt_padding[PAD_FMT_DAYOFMONTH][PadIndex], 312 pt, ptlim, loc); 313 continue; 314 case 'E': 315 if (Ealternative || Oalternative) 316 break; 317 Ealternative++; 318 goto label; 319 case 'O': 320 /* 321 ** Locale modifiers of C99 and later. 322 ** The sequences 323 ** %Ec %EC %Ex %EX %Ey %EY 324 ** %Od %oe %OH %OI %Om %OM 325 ** %OS %Ou %OU %OV %Ow %OW %Oy 326 ** are supposed to provide alternative 327 ** representations. 328 */ 329 if (Ealternative || Oalternative) 330 break; 331 Oalternative++; 332 goto label; 333 case 'e': 334 pt = _conv(t->tm_mday, 335 fmt_padding[PAD_FMT_SDAYOFMONTH][PadIndex], 336 pt, ptlim, loc); 337 continue; 338 case 'F': 339 pt = _fmt(sp, "%Y-%m-%d", t, pt, ptlim, warnp, 340 loc); 341 continue; 342 case 'H': 343 pt = _conv(t->tm_hour, 344 fmt_padding[PAD_FMT_HMS][PadIndex], 345 pt, ptlim, loc); 346 continue; 347 case 'I': 348 pt = _conv((t->tm_hour % 12) ? 349 (t->tm_hour % 12) : 12, 350 fmt_padding[PAD_FMT_HMS][PadIndex], 351 pt, ptlim, loc); 352 continue; 353 case 'j': 354 pt = _conv(t->tm_yday + 1, 355 fmt_padding[PAD_FMT_DAYOFYEAR][PadIndex], 356 pt, ptlim, loc); 357 continue; 358 case 'k': 359 /* 360 ** This used to be... 361 ** _conv(t->tm_hour % 12 ? 362 ** t->tm_hour % 12 : 12, 2, ' '); 363 ** ...and has been changed to the below to 364 ** match SunOS 4.1.1 and Arnold Robbins' 365 ** strftime version 3.0. That is, "%k" and 366 ** "%l" have been swapped. 367 ** (ado, 1993-05-24) 368 */ 369 pt = _conv(t->tm_hour, 370 fmt_padding[PAD_FMT_SHMS][PadIndex], 371 pt, ptlim, loc); 372 continue; 373 #ifdef KITCHEN_SINK 374 case 'K': 375 /* 376 ** After all this time, still unclaimed! 377 */ 378 pt = _add("kitchen sink", pt, ptlim); 379 continue; 380 #endif /* defined KITCHEN_SINK */ 381 case 'l': 382 /* 383 ** This used to be... 384 ** _conv(t->tm_hour, 2, ' '); 385 ** ...and has been changed to the below to 386 ** match SunOS 4.1.1 and Arnold Robbin's 387 ** strftime version 3.0. That is, "%k" and 388 ** "%l" have been swapped. 389 ** (ado, 1993-05-24) 390 */ 391 pt = _conv((t->tm_hour % 12) ? 392 (t->tm_hour % 12) : 12, 393 fmt_padding[PAD_FMT_SHMS][PadIndex], 394 pt, ptlim, loc); 395 continue; 396 case 'M': 397 pt = _conv(t->tm_min, 398 fmt_padding[PAD_FMT_HMS][PadIndex], 399 pt, ptlim, loc); 400 continue; 401 case 'm': 402 pt = _conv(t->tm_mon + 1, 403 fmt_padding[PAD_FMT_MONTH][PadIndex], 404 pt, ptlim, loc); 405 continue; 406 case 'n': 407 pt = _add("\n", pt, ptlim); 408 continue; 409 case 'p': 410 pt = _add((t->tm_hour >= (HOURSPERDAY / 2)) ? 411 tptr->am_pm[1] : 412 tptr->am_pm[0], 413 pt, ptlim); 414 continue; 415 case 'R': 416 pt = _fmt(sp, "%H:%M", t, pt, ptlim, warnp, 417 loc); 418 continue; 419 case 'r': 420 pt = _fmt(sp, tptr->t_fmt_ampm, t, 421 pt, ptlim, warnp, loc); 422 continue; 423 case 'S': 424 pt = _conv(t->tm_sec, 425 fmt_padding[PAD_FMT_HMS][PadIndex], 426 pt, ptlim, loc); 427 continue; 428 case 's': 429 { 430 struct tm tm; 431 char buf[INT_STRLEN_MAXIMUM( 432 time_t) + 1]; 433 time_t mkt; 434 435 tm.tm_sec = t->tm_sec; 436 tm.tm_min = t->tm_min; 437 tm.tm_hour = t->tm_hour; 438 tm.tm_mday = t->tm_mday; 439 tm.tm_mon = t->tm_mon; 440 tm.tm_year = t->tm_year; 441 442 /* Get the time_t value for TM. 443 Native time_t, or its redefinition 444 by localtime.c above, is wide enough 445 so that this cannot overflow. */ 446 #if defined TM_GMTOFF 447 mkt = timeoff(&tm, t->TM_GMTOFF); 448 #else 449 tm.tm_isdst = t->tm_isdst; 450 mkt = mktime_z(sp, &tm); 451 #endif 452 /* CONSTCOND */ 453 if (TYPE_SIGNED(time_t)) { 454 intmax_t n = mkt; 455 (void)snprintf(buf, sizeof(buf), 456 "%"PRIdMAX, n); 457 } else { 458 /*LINTED possibly unreached*/ 459 uintmax_t n = mkt; 460 (void)snprintf(buf, sizeof(buf), 461 "%"PRIuMAX, n); 462 } 463 pt = _add(buf, pt, ptlim); 464 } 465 continue; 466 case 'T': 467 pt = _fmt(sp, "%H:%M:%S", t, pt, ptlim, warnp, 468 loc); 469 continue; 470 case 't': 471 pt = _add("\t", pt, ptlim); 472 continue; 473 case 'U': 474 pt = _conv((t->tm_yday + DAYSPERWEEK - 475 t->tm_wday) / DAYSPERWEEK, 476 fmt_padding[PAD_FMT_WEEKOFYEAR][PadIndex], 477 pt, ptlim, loc); 478 continue; 479 case 'u': 480 /* 481 ** From Arnold Robbins' strftime version 3.0: 482 ** "ISO 8601: Weekday as a decimal number 483 ** [1 (Monday) - 7]" 484 ** (ado, 1993-05-24) 485 */ 486 pt = _conv((t->tm_wday == 0) ? 487 DAYSPERWEEK : t->tm_wday, 488 "%d", pt, ptlim, loc); 489 continue; 490 case 'V': /* ISO 8601 week number */ 491 case 'G': /* ISO 8601 year (four digits) */ 492 case 'g': /* ISO 8601 year (two digits) */ 493 /* 494 ** From Arnold Robbins' strftime version 3.0: "the week number of the 495 ** year (the first Monday as the first day of week 1) as a decimal number 496 ** (01-53)." 497 ** (ado, 1993-05-24) 498 ** 499 ** From <https://www.cl.cam.ac.uk/~mgk25/iso-time.html> by Markus Kuhn: 500 ** "Week 01 of a year is per definition the first week which has the 501 ** Thursday in this year, which is equivalent to the week which contains 502 ** the fourth day of January. In other words, the first week of a new year 503 ** is the week which has the majority of its days in the new year. Week 01 504 ** might also contain days from the previous year and the week before week 505 ** 01 of a year is the last week (52 or 53) of the previous year even if 506 ** it contains days from the new year. A week starts with Monday (day 1) 507 ** and ends with Sunday (day 7). For example, the first week of the year 508 ** 1997 lasts from 1996-12-30 to 1997-01-05..." 509 ** (ado, 1996-01-02) 510 */ 511 { 512 int year; 513 int base; 514 int yday; 515 int wday; 516 int w; 517 518 year = t->tm_year; 519 base = TM_YEAR_BASE; 520 yday = t->tm_yday; 521 wday = t->tm_wday; 522 for ( ; ; ) { 523 int len; 524 int bot; 525 int top; 526 527 len = isleap_sum(year, base) ? 528 DAYSPERLYEAR : 529 DAYSPERNYEAR; 530 /* 531 ** What yday (-3 ... 3) does 532 ** the ISO year begin on? 533 */ 534 bot = ((yday + 11 - wday) % 535 DAYSPERWEEK) - 3; 536 /* 537 ** What yday does the NEXT 538 ** ISO year begin on? 539 */ 540 top = bot - 541 (len % DAYSPERWEEK); 542 if (top < -3) 543 top += DAYSPERWEEK; 544 top += len; 545 if (yday >= top) { 546 ++base; 547 w = 1; 548 break; 549 } 550 if (yday >= bot) { 551 w = 1 + ((yday - bot) / 552 DAYSPERWEEK); 553 break; 554 } 555 --base; 556 yday += isleap_sum(year, base) ? 557 DAYSPERLYEAR : 558 DAYSPERNYEAR; 559 } 560 #ifdef XPG4_1994_04_09 561 if ((w == 52 && 562 t->tm_mon == TM_JANUARY) || 563 (w == 1 && 564 t->tm_mon == TM_DECEMBER)) 565 w = 53; 566 #endif /* defined XPG4_1994_04_09 */ 567 if (*format == 'V') 568 pt = _conv(w, 569 fmt_padding[ 570 PAD_FMT_WEEKOFYEAR][ 571 PadIndex], pt, ptlim, loc); 572 else if (*format == 'g') { 573 *warnp = IN_ALL; 574 pt = _yconv(year, base, 575 false, true, 576 pt, ptlim, loc); 577 } else pt = _yconv(year, base, 578 true, true, 579 pt, ptlim, loc); 580 } 581 continue; 582 case 'v': 583 /* 584 ** From Arnold Robbins' strftime version 3.0: 585 ** "date as dd-bbb-YYYY" 586 ** (ado, 1993-05-24) 587 */ 588 pt = _fmt(sp, "%e-%b-%Y", t, pt, ptlim, warnp, 589 loc); 590 continue; 591 case 'W': 592 pt = _conv((t->tm_yday + DAYSPERWEEK - 593 (t->tm_wday ? 594 (t->tm_wday - 1) : 595 (DAYSPERWEEK - 1))) / DAYSPERWEEK, 596 fmt_padding[PAD_FMT_WEEKOFYEAR][PadIndex], 597 pt, ptlim, loc); 598 continue; 599 case 'w': 600 pt = _conv(t->tm_wday, "%d", pt, ptlim, loc); 601 continue; 602 case 'X': 603 pt = _fmt(sp, tptr->t_fmt, t, pt, 604 ptlim, warnp, loc); 605 continue; 606 case 'x': 607 { 608 enum warn warn2 = IN_SOME; 609 610 pt = _fmt(sp, tptr->d_fmt, t, pt, 611 ptlim, &warn2, loc); 612 if (warn2 == IN_ALL) 613 warn2 = IN_THIS; 614 if (warn2 > *warnp) 615 *warnp = warn2; 616 } 617 continue; 618 case 'y': 619 *warnp = IN_ALL; 620 pt = _yconv(t->tm_year, TM_YEAR_BASE, 621 false, true, 622 pt, ptlim, loc); 623 continue; 624 case 'Y': 625 pt = _yconv(t->tm_year, TM_YEAR_BASE, 626 true, true, 627 pt, ptlim, loc); 628 continue; 629 case 'Z': 630 #ifdef TM_ZONE 631 pt = _add(t->TM_ZONE, pt, ptlim); 632 #elif HAVE_TZNAME 633 if (t->tm_isdst >= 0) { 634 int oerrno = errno, dst = t->tm_isdst; 635 const char *z = 636 tzgetname(sp, dst); 637 if (z == NULL) 638 z = tzgetname(sp, !dst); 639 if (z != NULL) 640 pt = _add(z, pt, ptlim); 641 errno = oerrno; 642 } 643 #endif 644 /* 645 ** C99 and later say that %Z must be 646 ** replaced by the empty string if the 647 ** time zone abbreviation is not 648 ** determinable. 649 */ 650 continue; 651 case 'z': 652 #if defined TM_GMTOFF || USG_COMPAT || ALTZONE 653 { 654 long diff; 655 char const * sign; 656 bool negative; 657 658 if (t->tm_isdst < 0) 659 continue; 660 # ifdef TM_GMTOFF 661 diff = (int)t->TM_GMTOFF; 662 # else 663 /* 664 ** C99 and later say that the UT offset must 665 ** be computed by looking only at 666 ** tm_isdst. This requirement is 667 ** incorrect, since it means the code 668 ** must rely on magic (in this case 669 ** altzone and timezone), and the 670 ** magic might not have the correct 671 ** offset. Doing things correctly is 672 ** tricky and requires disobeying the standard; 673 ** see GNU C strftime for details. 674 ** For now, punt and conform to the 675 ** standard, even though it's incorrect. 676 ** 677 ** C99 and later say that %z must be replaced by 678 ** the empty string if the time zone is not 679 ** determinable, so output nothing if the 680 ** appropriate variables are not available. 681 */ 682 # ifndef STD_INSPIRED 683 if (t->tm_isdst == 0) 684 # if USG_COMPAT 685 diff = -timezone; 686 # else 687 continue; 688 # endif 689 else 690 # if ALTZONE 691 diff = -altzone; 692 # else 693 continue; 694 # endif 695 # else 696 { 697 struct tm tmp; 698 time_t lct, gct; 699 700 /* 701 ** Get calendar time from t 702 ** being treated as local. 703 */ 704 tmp = *t; /* mktime discards const */ 705 lct = mktime_z(sp, &tmp); 706 707 if (lct == (time_t)-1) 708 continue; 709 710 /* 711 ** Get calendar time from t 712 ** being treated as GMT. 713 **/ 714 tmp = *t; /* mktime discards const */ 715 gct = timegm(&tmp); 716 717 if (gct == (time_t)-1) 718 continue; 719 720 /* LINTED difference will fit int */ 721 diff = (intmax_t)gct - (intmax_t)lct; 722 } 723 # endif 724 # endif 725 negative = diff < 0; 726 if (diff == 0) { 727 # ifdef TM_ZONE 728 negative = t->TM_ZONE[0] == '-'; 729 # else 730 negative = t->tm_isdst < 0; 731 # if HAVE_TZNAME 732 if (tzname[t->tm_isdst != 0][0] == '-') 733 negative = true; 734 # endif 735 # endif 736 } 737 if (negative) { 738 sign = "-"; 739 diff = -diff; 740 } else sign = "+"; 741 pt = _add(sign, pt, ptlim); 742 diff /= SECSPERMIN; 743 diff = (diff / MINSPERHOUR) * 100 + 744 (diff % MINSPERHOUR); 745 _DIAGASSERT(__type_fit(int, diff)); 746 pt = _conv((int)diff, 747 fmt_padding[PAD_FMT_YEAR][PadIndex], 748 pt, ptlim, loc); 749 } 750 #endif 751 continue; 752 case '+': 753 #ifdef notyet 754 /* XXX: no date_fmt in _TimeLocale */ 755 pt = _fmt(sp, tptr->date_fmt, t, 756 pt, ptlim, warnp, loc); 757 #else 758 pt = _fmt(sp, "%a %b %e %H:%M:%S %Z %Y", t, 759 pt, ptlim, warnp, loc); 760 #endif 761 continue; 762 case '-': 763 if (PadIndex != PAD_DEFAULT) 764 break; 765 PadIndex = PAD_LESS; 766 goto label; 767 case '_': 768 if (PadIndex != PAD_DEFAULT) 769 break; 770 PadIndex = PAD_SPACE; 771 goto label; 772 case '0': 773 if (PadIndex != PAD_DEFAULT) 774 break; 775 PadIndex = PAD_ZERO; 776 goto label; 777 case '%': 778 break; 779 } 780 } 781 if (pt == ptlim) 782 break; 783 *pt++ = *format; 784 } 785 return pt; 786 } 787 788 size_t 789 strftime(char *restrict s, size_t maxsize, char const *restrict format, 790 struct tm const *restrict t) 791 { 792 size_t r; 793 794 rwlock_wrlock(&__lcl_lock); 795 tzset_unlocked(); 796 r = strftime_z(__lclptr, s, maxsize, format, t); 797 rwlock_unlock(&__lcl_lock); 798 799 return r; 800 } 801 802 size_t 803 strftime_l(char * __restrict s, size_t maxsize, const char * __restrict format, 804 const struct tm * __restrict t, locale_t loc) 805 { 806 size_t r; 807 808 rwlock_wrlock(&__lcl_lock); 809 tzset_unlocked(); 810 r = strftime_lz(__lclptr, s, maxsize, format, t, loc); 811 rwlock_unlock(&__lcl_lock); 812 813 return r; 814 } 815 816 static char * 817 _conv(int n, const char *format, char *pt, const char *ptlim, locale_t loc) 818 { 819 char buf[INT_STRLEN_MAXIMUM(int) + 1]; 820 821 (void) snprintf_l(buf, sizeof(buf), loc, format, n); 822 return _add(buf, pt, ptlim); 823 } 824 825 static char * 826 _add(const char *str, char *pt, const char *ptlim) 827 { 828 while (pt < ptlim && (*pt = *str++) != '\0') 829 ++pt; 830 return pt; 831 } 832 833 /* 834 ** POSIX and the C Standard are unclear or inconsistent about 835 ** what %C and %y do if the year is negative or exceeds 9999. 836 ** Use the convention that %C concatenated with %y yields the 837 ** same output as %Y, and that %Y contains at least 4 bytes, 838 ** with more only if necessary. 839 */ 840 841 static char * 842 _yconv(int a, int b, bool convert_top, bool convert_yy, 843 char *pt, const char * ptlim, locale_t loc) 844 { 845 int lead; 846 int trail; 847 848 int DIVISOR = 100; 849 trail = a % DIVISOR + b % DIVISOR; 850 lead = a / DIVISOR + b / DIVISOR + trail / DIVISOR; 851 trail %= DIVISOR; 852 if (trail < 0 && lead > 0) { 853 trail += DIVISOR; 854 --lead; 855 } else if (lead < 0 && trail > 0) { 856 trail -= DIVISOR; 857 ++lead; 858 } 859 if (convert_top) { 860 if (lead == 0 && trail < 0) 861 pt = _add("-0", pt, ptlim); 862 else pt = _conv(lead, "%02d", pt, ptlim, loc); 863 } 864 if (convert_yy) 865 pt = _conv(((trail < 0) ? -trail : trail), "%02d", pt, ptlim, 866 loc); 867 return pt; 868 } 869
Indexes created Fri Sep 26 20:09:58 GMT 2025