1 /* 2 * @(#)strftime.c 8.3 3 * $NetBSD: strftime.c,v 1.19 2009/01/11 02:46:30 christos Exp $ 4 * $DragonFly: src/lib/libc/stdtime/strftime.c,v 1.7 2008/10/19 20:15:58 swildner Exp $ 5 */ 6 7 /* 8 ** Based on the UCB version with the ID appearing below. 9 ** This is ANSIish only when "multibyte character == plain character". 10 */ 11 12 /* 13 ** We don't use these extensions in strftime operation even when 14 ** supported by the local tzcode configuration. A strictly 15 ** conforming C application may leave them in undefined state. 16 */ 17 18 #ifdef _LIBC 19 #undef TM_ZONE 20 #undef TM_GMTOFF 21 #endif 22 23 /* 24 ** Copyright (c) 1989, 1993 25 ** The Regents of the University of California. All rights reserved. 26 ** 27 ** Redistribution and use in source and binary forms, with or without 28 ** modification, are permitted provided that the following conditions 29 ** are met: 30 ** 1. Redistributions of source code must retain the above copyright 31 ** notice, this list of conditions and the following disclaimer. 32 ** 2. Redistributions in binary form must reproduce the above copyright 33 ** notice, this list of conditions and the following disclaimer in the 34 ** documentation and/or other materials provided with the distribution. 35 ** 3. All advertising materials mentioning features or use of this software 36 ** must display the following acknowledgement: 37 ** This product includes software developed by the University of 38 ** California, Berkeley and its contributors. 39 ** 4. Neither the name of the University nor the names of its contributors 40 ** may be used to endorse or promote products derived from this software 41 ** without specific prior written permission. 42 ** 43 ** THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 44 ** ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 45 ** IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 46 ** ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 47 ** FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 48 ** DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 49 ** OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 50 ** HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 51 ** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 52 ** OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 53 ** SUCH DAMAGE. 54 */ 55 56 #include <sys/localedef.h> 57 #include <fcntl.h> 58 #include <locale.h> 59 #include <time.h> 60 61 #include "private.h" 62 #include "tzfile.h" 63 64 #define Locale _CurrentTimeLocale 65 66 static char * _add(const char *, char *, const char *); 67 static char * _conv(int, const char *, char *, const char *); 68 static char * _fmt(const char *, const struct tm *, char *, 69 const char *, int *); 70 static char * _yconv(int, int, int, int, char *, const char *); 71 72 #define NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU 73 74 #ifndef YEAR_2000_NAME 75 #define YEAR_2000_NAME "CHECK_STRFTIME_FORMATS_FOR_TWO_DIGIT_YEARS" 76 #endif /* !defined YEAR_2000_NAME */ 77 78 #define IN_NONE 0 79 #define IN_SOME 1 80 #define IN_THIS 2 81 #define IN_ALL 3 82 83 size_t 84 strftime(char * __restrict s, size_t maxsize, const char * __restrict format, 85 const struct tm * __restrict t) 86 { 87 char * p; 88 int warn; 89 90 tzset(); 91 warn = IN_NONE; 92 p = _fmt(((format == NULL) ? "%c" : format), t, s, s + maxsize, &warn); 93 #ifndef NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU 94 if (warn != IN_NONE && getenv(YEAR_2000_NAME) != NULL) { 95 fprintf(stderr, "\n"); 96 if (format == NULL) 97 fprintf(stderr, "NULL strftime format "); 98 else fprintf(stderr, "strftime format \"%s\" ", 99 format); 100 fprintf(stderr, "yields only two digits of years in "); 101 if (warn == IN_SOME) 102 fprintf(stderr, "some locales"); 103 else if (warn == IN_THIS) 104 fprintf(stderr, "the current locale"); 105 else fprintf(stderr, "all locales"); 106 fprintf(stderr, "\n"); 107 } 108 #endif /* !defined NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU */ 109 if (p == s + maxsize) 110 return 0; 111 *p = '\0'; 112 return p - s; 113 } 114 115 static char * 116 _fmt(const char *format, const struct tm * const t, char *pt, 117 const char * const ptlim, int * warnp) 118 { 119 for ( ; *format; ++format) { 120 if (*format == '%') { 121 label: 122 switch (*++format) { 123 case '\0': 124 --format; 125 break; 126 case 'A': 127 pt = _add((t->tm_wday < 0 || 128 t->tm_wday >= DAYSPERWEEK) ? 129 "?" : Locale->day[t->tm_wday], 130 pt, ptlim); 131 continue; 132 case 'a': 133 pt = _add((t->tm_wday < 0 || 134 t->tm_wday >= DAYSPERWEEK) ? 135 "?" : Locale->abday[t->tm_wday], 136 pt, ptlim); 137 continue; 138 case 'B': 139 pt = _add((t->tm_mon < 0 || 140 t->tm_mon >= MONSPERYEAR) ? 141 "?" : Locale->mon[t->tm_mon], 142 pt, ptlim); 143 continue; 144 case 'b': 145 case 'h': 146 pt = _add((t->tm_mon < 0 || 147 t->tm_mon >= MONSPERYEAR) ? 148 "?" : Locale->abmon[t->tm_mon], 149 pt, ptlim); 150 continue; 151 case 'C': 152 /* 153 ** %C used to do a... 154 ** _fmt("%a %b %e %X %Y", t); 155 ** ...whereas now POSIX 1003.2 calls for 156 ** something completely different. 157 ** (ado, 1993-05-24) 158 */ 159 pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 0, 160 pt, ptlim); 161 continue; 162 case 'c': 163 { 164 int warn2 = IN_SOME; 165 166 pt = _fmt(Locale->d_t_fmt, t, pt, ptlim, &warn2); 167 if (warn2 == IN_ALL) 168 warn2 = IN_THIS; 169 if (warn2 > *warnp) 170 *warnp = warn2; 171 } 172 continue; 173 case 'D': 174 pt = _fmt("%m/%d/%y", t, pt, ptlim, warnp); 175 continue; 176 case 'd': 177 pt = _conv(t->tm_mday, "%02d", pt, ptlim); 178 continue; 179 case 'E': 180 case 'O': 181 /* 182 ** C99 locale modifiers. 183 ** The sequences 184 ** %Ec %EC %Ex %EX %Ey %EY 185 ** %Od %oe %OH %OI %Om %OM 186 ** %OS %Ou %OU %OV %Ow %OW %Oy 187 ** are supposed to provide alternate 188 ** representations. 189 */ 190 goto label; 191 case 'e': 192 pt = _conv(t->tm_mday, "%2d", pt, ptlim); 193 continue; 194 case 'F': 195 pt = _fmt("%Y-%m-%d", t, pt, ptlim, warnp); 196 continue; 197 case 'H': 198 pt = _conv(t->tm_hour, "%02d", pt, ptlim); 199 continue; 200 case 'I': 201 pt = _conv((t->tm_hour % 12) ? 202 (t->tm_hour % 12) : 12, 203 "%02d", pt, ptlim); 204 continue; 205 case 'j': 206 pt = _conv(t->tm_yday + 1, "%03d", pt, ptlim); 207 continue; 208 case 'k': 209 /* 210 ** This used to be... 211 ** _conv(t->tm_hour % 12 ? 212 ** t->tm_hour % 12 : 12, 2, ' '); 213 ** ...and has been changed to the below to 214 ** match SunOS 4.1.1 and Arnold Robbins' 215 ** strftime version 3.0. That is, "%k" and 216 ** "%l" have been swapped. 217 ** (ado, 1993-05-24) 218 */ 219 pt = _conv(t->tm_hour, "%2d", pt, ptlim); 220 continue; 221 #ifdef KITCHEN_SINK 222 case 'K': 223 /* 224 ** After all this time, still unclaimed! 225 */ 226 pt = _add("kitchen sink", pt, ptlim); 227 continue; 228 #endif /* defined KITCHEN_SINK */ 229 case 'l': 230 /* 231 ** This used to be... 232 ** _conv(t->tm_hour, 2, ' '); 233 ** ...and has been changed to the below to 234 ** match SunOS 4.1.1 and Arnold Robbin's 235 ** strftime version 3.0. That is, "%k" and 236 ** "%l" have been swapped. 237 ** (ado, 1993-05-24) 238 */ 239 pt = _conv((t->tm_hour % 12) ? 240 (t->tm_hour % 12) : 12, 241 "%2d", pt, ptlim); 242 continue; 243 case 'M': 244 pt = _conv(t->tm_min, "%02d", pt, ptlim); 245 continue; 246 case 'm': 247 pt = _conv(t->tm_mon + 1, "%02d", pt, ptlim); 248 continue; 249 case 'n': 250 pt = _add("\n", pt, ptlim); 251 continue; 252 case 'p': 253 pt = _add((t->tm_hour >= (HOURSPERDAY / 2)) ? 254 Locale->am_pm[1] : 255 Locale->am_pm[0], 256 pt, ptlim); 257 continue; 258 case 'R': 259 pt = _fmt("%H:%M", t, pt, ptlim, warnp); 260 continue; 261 case 'r': 262 pt = _fmt(Locale->t_fmt_ampm, t, pt, ptlim, 263 warnp); 264 continue; 265 case 'S': 266 pt = _conv(t->tm_sec, "%02d", pt, ptlim); 267 continue; 268 case 's': 269 { 270 struct tm tm; 271 char buf[INT_STRLEN_MAXIMUM( 272 time_t) + 1]; 273 time_t mkt; 274 275 tm = *t; 276 mkt = mktime(&tm); 277 /* CONSTCOND */ 278 if (TYPE_SIGNED(time_t)) 279 snprintf(buf, sizeof(buf), 280 "%ld", (long) mkt); 281 else snprintf(buf, sizeof(buf), 282 "%lu", (unsigned long) 283 mkt); 284 pt = _add(buf, pt, ptlim); 285 } 286 continue; 287 case 'T': 288 pt = _fmt("%H:%M:%S", t, pt, ptlim, warnp); 289 continue; 290 case 't': 291 pt = _add("\t", pt, ptlim); 292 continue; 293 case 'U': 294 pt = _conv((t->tm_yday + DAYSPERWEEK - 295 t->tm_wday) / DAYSPERWEEK, 296 "%02d", pt, ptlim); 297 continue; 298 case 'u': 299 /* 300 ** From Arnold Robbins' strftime version 3.0: 301 ** "ISO 8601: Weekday as a decimal number 302 ** [1 (Monday) - 7]" 303 ** (ado, 1993-05-24) 304 */ 305 pt = _conv((t->tm_wday == 0) ? 306 DAYSPERWEEK : t->tm_wday, 307 "%d", pt, ptlim); 308 continue; 309 case 'V': /* ISO 8601 week number */ 310 case 'G': /* ISO 8601 year (four digits) */ 311 case 'g': /* ISO 8601 year (two digits) */ 312 /* 313 ** From Arnold Robbins' strftime version 3.0: "the week number of the 314 ** year (the first Monday as the first day of week 1) as a decimal number 315 ** (01-53)." 316 ** (ado, 1993-05-24) 317 ** 318 ** From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn: 319 ** "Week 01 of a year is per definition the first week which has the 320 ** Thursday in this year, which is equivalent to the week which contains 321 ** the fourth day of January. In other words, the first week of a new year 322 ** is the week which has the majority of its days in the new year. Week 01 323 ** might also contain days from the previous year and the week before week 324 ** 01 of a year is the last week (52 or 53) of the previous year even if 325 ** it contains days from the new year. A week starts with Monday (day 1) 326 ** and ends with Sunday (day 7). For example, the first week of the year 327 ** 1997 lasts from 1996-12-30 to 1997-01-05..." 328 ** (ado, 1996-01-02) 329 */ 330 { 331 int year; 332 int base; 333 int yday; 334 int wday; 335 int w; 336 337 year = t->tm_year; 338 base = TM_YEAR_BASE; 339 yday = t->tm_yday; 340 wday = t->tm_wday; 341 for ( ; ; ) { 342 int len; 343 int bot; 344 int top; 345 346 len = isleap_sum(year, base) ? 347 DAYSPERLYEAR : 348 DAYSPERNYEAR; 349 /* 350 ** What yday (-3 ... 3) does 351 ** the ISO year begin on? 352 */ 353 bot = ((yday + 11 - wday) % 354 DAYSPERWEEK) - 3; 355 /* 356 ** What yday does the NEXT 357 ** ISO year begin on? 358 */ 359 top = bot - 360 (len % DAYSPERWEEK); 361 if (top < -3) 362 top += DAYSPERWEEK; 363 top += len; 364 if (yday >= top) { 365 ++base; 366 w = 1; 367 break; 368 } 369 if (yday >= bot) { 370 w = 1 + ((yday - bot) / 371 DAYSPERWEEK); 372 break; 373 } 374 --base; 375 yday += isleap_sum(year, base) ? 376 DAYSPERLYEAR : 377 DAYSPERNYEAR; 378 } 379 #ifdef XPG4_1994_04_09 380 if ((w == 52 && 381 t->tm_mon == TM_JANUARY) || 382 (w == 1 && 383 t->tm_mon == TM_DECEMBER)) 384 w = 53; 385 #endif /* defined XPG4_1994_04_09 */ 386 if (*format == 'V') 387 pt = _conv(w, "%02d", 388 pt, ptlim); 389 else if (*format == 'g') { 390 *warnp = IN_ALL; 391 pt = _yconv(year, base, 0, 1, 392 pt, ptlim); 393 } else pt = _yconv(year, base, 1, 1, 394 pt, ptlim); 395 } 396 continue; 397 case 'v': 398 /* 399 ** From Arnold Robbins' strftime version 3.0: 400 ** "date as dd-bbb-YYYY" 401 ** (ado, 1993-05-24) 402 */ 403 pt = _fmt("%e-%b-%Y", t, pt, ptlim, warnp); 404 continue; 405 case 'W': 406 pt = _conv((t->tm_yday + DAYSPERWEEK - 407 (t->tm_wday ? 408 (t->tm_wday - 1) : 409 (DAYSPERWEEK - 1))) / DAYSPERWEEK, 410 "%02d", pt, ptlim); 411 continue; 412 case 'w': 413 pt = _conv(t->tm_wday, "%d", pt, ptlim); 414 continue; 415 case 'X': 416 pt = _fmt(Locale->t_fmt, t, pt, ptlim, warnp); 417 continue; 418 case 'x': 419 { 420 int warn2 = IN_SOME; 421 422 pt = _fmt(Locale->d_fmt, t, pt, ptlim, &warn2); 423 if (warn2 == IN_ALL) 424 warn2 = IN_THIS; 425 if (warn2 > *warnp) 426 *warnp = warn2; 427 } 428 continue; 429 case 'y': 430 *warnp = IN_ALL; 431 pt = _yconv(t->tm_year, TM_YEAR_BASE, 0, 1, 432 pt, ptlim); 433 continue; 434 case 'Y': 435 pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 1, 436 pt, ptlim); 437 continue; 438 case 'Z': 439 #ifdef TM_ZONE 440 if (t->TM_ZONE != NULL) 441 pt = _add(t->TM_ZONE, pt, ptlim); 442 else 443 #endif /* defined TM_ZONE */ 444 if (t->tm_isdst >= 0) 445 pt = _add(tzname[t->tm_isdst != 0], 446 pt, ptlim); 447 /* 448 ** C99 says that %Z must be replaced by the 449 ** empty string if the time zone is not 450 ** determinable. 451 */ 452 continue; 453 case 'z': 454 { 455 int diff; 456 char const * sign; 457 458 if (t->tm_isdst < 0) 459 continue; 460 #ifdef TM_GMTOFF 461 diff = (int)t->TM_GMTOFF; 462 #else /* !defined TM_GMTOFF */ 463 /* 464 ** C99 says that the UTC offset must 465 ** be computed by looking only at 466 ** tm_isdst. This requirement is 467 ** incorrect, since it means the code 468 ** must rely on magic (in this case 469 ** altzone and timezone), and the 470 ** magic might not have the correct 471 ** offset. Doing things correctly is 472 ** tricky and requires disobeying C99; 473 ** see GNU C strftime for details. 474 ** For now, punt and conform to the 475 ** standard, even though it's incorrect. 476 ** 477 ** C99 says that %z must be replaced by the 478 ** empty string if the time zone is not 479 ** determinable, so output nothing if the 480 ** appropriate variables are not available. 481 */ 482 { 483 struct tm tmp; 484 time_t lct, gct; 485 486 /* 487 ** Get calendar time from t 488 ** being treated as local. 489 */ 490 tmp = *t; /* mktime discards const */ 491 lct = mktime(&tmp); 492 493 if (lct == (time_t)-1) 494 continue; 495 496 /* 497 ** Get calendar time from t 498 ** being treated as GMT. 499 **/ 500 tmp = *t; /* mktime discards const */ 501 gct = timegm(&tmp); 502 503 if (gct == (time_t)-1) 504 continue; 505 506 /* LINTED difference will fit int */ 507 diff = (intmax_t)gct - (intmax_t)lct; 508 } 509 #endif /* !defined TM_GMTOFF */ 510 if (diff < 0) { 511 sign = "-"; 512 diff = -diff; 513 } else sign = "+"; 514 pt = _add(sign, pt, ptlim); 515 diff /= SECSPERMIN; 516 diff = (diff / MINSPERHOUR) * 100 + 517 (diff % MINSPERHOUR); 518 pt = _conv(diff, "%04d", pt, ptlim); 519 } 520 continue; 521 case '+': 522 pt = _fmt(Locale->d_t_fmt, t, pt, ptlim, 523 warnp); 524 continue; 525 case '%': 526 /* 527 ** X311J/88-090 (4.12.3.5): if conversion char is 528 ** undefined, behavior is undefined. Print out the 529 ** character itself as printf(3) also does. 530 */ 531 default: 532 break; 533 } 534 } 535 if (pt == ptlim) 536 break; 537 *pt++ = *format; 538 } 539 return pt; 540 } 541 542 static char * 543 _conv(const int n, const char * const format, char * const pt, 544 const char * const ptlim) 545 { 546 char buf[INT_STRLEN_MAXIMUM(int) + 1]; 547 548 snprintf(buf, sizeof(buf), format, n); 549 return _add(buf, pt, ptlim); 550 } 551 552 static char * 553 _add(const char *str, char *pt, const char * const ptlim) 554 { 555 while (pt < ptlim && (*pt = *str++) != '\0') 556 ++pt; 557 return pt; 558 } 559 560 /* 561 ** POSIX and the C Standard are unclear or inconsistent about 562 ** what %C and %y do if the year is negative or exceeds 9999. 563 ** Use the convention that %C concatenated with %y yields the 564 ** same output as %Y, and that %Y contains at least 4 bytes, 565 ** with more only if necessary. 566 */ 567 568 static char * 569 _yconv(const int a, const int b, const int convert_top, const int convert_yy, 570 char *pt, const char * const ptlim) 571 { 572 int lead; 573 int trail; 574 575 #define DIVISOR 100 576 trail = a % DIVISOR + b % DIVISOR; 577 lead = a / DIVISOR + b / DIVISOR + trail / DIVISOR; 578 trail %= DIVISOR; 579 if (trail < 0 && lead > 0) { 580 trail += DIVISOR; 581 --lead; 582 } else if (lead < 0 && trail > 0) { 583 trail -= DIVISOR; 584 ++lead; 585 } 586 if (convert_top) { 587 if (lead == 0 && trail < 0) 588 pt = _add("-0", pt, ptlim); 589 else pt = _conv(lead, "%02d", pt, ptlim); 590 } 591 if (convert_yy) 592 pt = _conv(((trail < 0) ? -trail : trail), "%02d", pt, ptlim); 593 return pt; 594 } 595