1 /* 2 * @(#)strftime.c 8.3 3 * $NetBSD: src/lib/libc/time/strftime.c,v 1.16 2004/05/12 23:03:11 kleink 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 * const s, const size_t maxsize, const char * const format, 85 const struct tm * const 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("%I:%M:%S %p", t, pt, ptlim, warnp); 263 continue; 264 case 'S': 265 pt = _conv(t->tm_sec, "%02d", pt, ptlim); 266 continue; 267 case 's': 268 { 269 struct tm tm; 270 char buf[INT_STRLEN_MAXIMUM( 271 time_t) + 1]; 272 time_t mkt; 273 274 tm = *t; 275 mkt = mktime(&tm); 276 /* CONSTCOND */ 277 if (TYPE_SIGNED(time_t)) 278 sprintf(buf, "%ld", 279 (long) mkt); 280 else sprintf(buf, "%lu", 281 (unsigned long) mkt); 282 pt = _add(buf, pt, ptlim); 283 } 284 continue; 285 case 'T': 286 pt = _fmt("%H:%M:%S", t, pt, ptlim, warnp); 287 continue; 288 case 't': 289 pt = _add("\t", pt, ptlim); 290 continue; 291 case 'U': 292 pt = _conv((t->tm_yday + DAYSPERWEEK - 293 t->tm_wday) / DAYSPERWEEK, 294 "%02d", pt, ptlim); 295 continue; 296 case 'u': 297 /* 298 ** From Arnold Robbins' strftime version 3.0: 299 ** "ISO 8601: Weekday as a decimal number 300 ** [1 (Monday) - 7]" 301 ** (ado, 1993-05-24) 302 */ 303 pt = _conv((t->tm_wday == 0) ? 304 DAYSPERWEEK : t->tm_wday, 305 "%d", pt, ptlim); 306 continue; 307 case 'V': /* ISO 8601 week number */ 308 case 'G': /* ISO 8601 year (four digits) */ 309 case 'g': /* ISO 8601 year (two digits) */ 310 /* 311 ** From Arnold Robbins' strftime version 3.0: "the week number of the 312 ** year (the first Monday as the first day of week 1) as a decimal number 313 ** (01-53)." 314 ** (ado, 1993-05-24) 315 ** 316 ** From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn: 317 ** "Week 01 of a year is per definition the first week which has the 318 ** Thursday in this year, which is equivalent to the week which contains 319 ** the fourth day of January. In other words, the first week of a new year 320 ** is the week which has the majority of its days in the new year. Week 01 321 ** might also contain days from the previous year and the week before week 322 ** 01 of a year is the last week (52 or 53) of the previous year even if 323 ** it contains days from the new year. A week starts with Monday (day 1) 324 ** and ends with Sunday (day 7). For example, the first week of the year 325 ** 1997 lasts from 1996-12-30 to 1997-01-05..." 326 ** (ado, 1996-01-02) 327 */ 328 { 329 int year; 330 int base; 331 int yday; 332 int wday; 333 int w; 334 335 year = t->tm_year; 336 base = TM_YEAR_BASE; 337 yday = t->tm_yday; 338 wday = t->tm_wday; 339 for ( ; ; ) { 340 int len; 341 int bot; 342 int top; 343 344 len = isleap_sum(year, base) ? 345 DAYSPERLYEAR : 346 DAYSPERNYEAR; 347 /* 348 ** What yday (-3 ... 3) does 349 ** the ISO year begin on? 350 */ 351 bot = ((yday + 11 - wday) % 352 DAYSPERWEEK) - 3; 353 /* 354 ** What yday does the NEXT 355 ** ISO year begin on? 356 */ 357 top = bot - 358 (len % DAYSPERWEEK); 359 if (top < -3) 360 top += DAYSPERWEEK; 361 top += len; 362 if (yday >= top) { 363 ++base; 364 w = 1; 365 break; 366 } 367 if (yday >= bot) { 368 w = 1 + ((yday - bot) / 369 DAYSPERWEEK); 370 break; 371 } 372 --base; 373 yday += isleap_sum(year, base) ? 374 DAYSPERLYEAR : 375 DAYSPERNYEAR; 376 } 377 #ifdef XPG4_1994_04_09 378 if ((w == 52 && 379 t->tm_mon == TM_JANUARY) || 380 (w == 1 && 381 t->tm_mon == TM_DECEMBER)) 382 w = 53; 383 #endif /* defined XPG4_1994_04_09 */ 384 if (*format == 'V') 385 pt = _conv(w, "%02d", 386 pt, ptlim); 387 else if (*format == 'g') { 388 *warnp = IN_ALL; 389 pt = _yconv(year, base, 0, 1, 390 pt, ptlim); 391 } else pt = _yconv(year, base, 1, 1, 392 pt, ptlim); 393 } 394 continue; 395 case 'v': 396 /* 397 ** From Arnold Robbins' strftime version 3.0: 398 ** "date as dd-bbb-YYYY" 399 ** (ado, 1993-05-24) 400 */ 401 pt = _fmt("%e-%b-%Y", t, pt, ptlim, warnp); 402 continue; 403 case 'W': 404 pt = _conv((t->tm_yday + DAYSPERWEEK - 405 (t->tm_wday ? 406 (t->tm_wday - 1) : 407 (DAYSPERWEEK - 1))) / DAYSPERWEEK, 408 "%02d", pt, ptlim); 409 continue; 410 case 'w': 411 pt = _conv(t->tm_wday, "%d", pt, ptlim); 412 continue; 413 case 'X': 414 pt = _fmt(Locale->t_fmt, t, pt, ptlim, warnp); 415 continue; 416 case 'x': 417 { 418 int warn2 = IN_SOME; 419 420 pt = _fmt(Locale->d_fmt, t, pt, ptlim, &warn2); 421 if (warn2 == IN_ALL) 422 warn2 = IN_THIS; 423 if (warn2 > *warnp) 424 *warnp = warn2; 425 } 426 continue; 427 case 'y': 428 *warnp = IN_ALL; 429 pt = _yconv(t->tm_year, TM_YEAR_BASE, 0, 1, 430 pt, ptlim); 431 continue; 432 case 'Y': 433 pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 1, 434 pt, ptlim); 435 continue; 436 case 'Z': 437 #ifdef TM_ZONE 438 if (t->TM_ZONE != NULL) 439 pt = _add(t->TM_ZONE, pt, ptlim); 440 else 441 #endif /* defined TM_ZONE */ 442 if (t->tm_isdst >= 0) 443 pt = _add(tzname[t->tm_isdst != 0], 444 pt, ptlim); 445 /* 446 ** C99 says that %Z must be replaced by the 447 ** empty string if the time zone is not 448 ** determinable. 449 */ 450 continue; 451 case 'z': 452 { 453 int diff; 454 char const * sign; 455 456 if (t->tm_isdst < 0) 457 continue; 458 #ifdef TM_GMTOFF 459 diff = (int)t->TM_GMTOFF; 460 #else /* !defined TM_GMTOFF */ 461 /* 462 ** C99 says that the UTC offset must 463 ** be computed by looking only at 464 ** tm_isdst. This requirement is 465 ** incorrect, since it means the code 466 ** must rely on magic (in this case 467 ** altzone and timezone), and the 468 ** magic might not have the correct 469 ** offset. Doing things correctly is 470 ** tricky and requires disobeying C99; 471 ** see GNU C strftime for details. 472 ** For now, punt and conform to the 473 ** standard, even though it's incorrect. 474 ** 475 ** C99 says that %z must be replaced by the 476 ** empty string if the time zone is not 477 ** determinable, so output nothing if the 478 ** appropriate variables are not available. 479 */ 480 { 481 struct tm tmp; 482 time_t lct, gct; 483 484 /* 485 ** Get calendar time from t 486 ** being treated as local. 487 */ 488 tmp = *t; /* mktime discards const */ 489 lct = mktime(&tmp); 490 491 if (lct == (time_t)-1) 492 continue; 493 494 /* 495 ** Get calendar time from t 496 ** being treated as GMT. 497 **/ 498 tmp = *t; /* mktime discards const */ 499 gct = timegm(&tmp); 500 501 if (gct == (time_t)-1) 502 continue; 503 504 /* LINTED difference will fit int */ 505 diff = (intmax_t)gct - (intmax_t)lct; 506 } 507 #endif /* !defined TM_GMTOFF */ 508 if (diff < 0) { 509 sign = "-"; 510 diff = -diff; 511 } else sign = "+"; 512 pt = _add(sign, pt, ptlim); 513 diff /= SECSPERMIN; 514 diff = (diff / MINSPERHOUR) * 100 + 515 (diff % MINSPERHOUR); 516 pt = _conv(diff, "%04d", pt, ptlim); 517 } 518 continue; 519 case '+': 520 pt = _fmt(Locale->d_t_fmt, t, pt, ptlim, 521 warnp); 522 continue; 523 case '%': 524 /* 525 ** X311J/88-090 (4.12.3.5): if conversion char is 526 ** undefined, behavior is undefined. Print out the 527 ** character itself as printf(3) also does. 528 */ 529 default: 530 break; 531 } 532 } 533 if (pt == ptlim) 534 break; 535 *pt++ = *format; 536 } 537 return pt; 538 } 539 540 static char * 541 _conv(const int n, const char * const format, char * const pt, 542 const char * const ptlim) 543 { 544 char buf[INT_STRLEN_MAXIMUM(int) + 1]; 545 546 sprintf(buf, format, n); 547 return _add(buf, pt, ptlim); 548 } 549 550 static char * 551 _add(const char *str, char *pt, const char * const ptlim) 552 { 553 while (pt < ptlim && (*pt = *str++) != '\0') 554 ++pt; 555 return pt; 556 } 557 558 /* 559 ** POSIX and the C Standard are unclear or inconsistent about 560 ** what %C and %y do if the year is negative or exceeds 9999. 561 ** Use the convention that %C concatenated with %y yields the 562 ** same output as %Y, and that %Y contains at least 4 bytes, 563 ** with more only if necessary. 564 */ 565 566 static char * 567 _yconv(const int a, const int b, const int convert_top, const int convert_yy, 568 char *pt, const char * const ptlim) 569 { 570 int lead; 571 int trail; 572 573 #define DIVISOR 100 574 trail = a % DIVISOR + b % DIVISOR; 575 lead = a / DIVISOR + b / DIVISOR + trail / DIVISOR; 576 trail %= DIVISOR; 577 if (trail < 0 && lead > 0) { 578 trail += DIVISOR; 579 --lead; 580 } else if (lead < 0 && trail > 0) { 581 trail -= DIVISOR; 582 ++lead; 583 } 584 if (convert_top) { 585 if (lead == 0 && trail < 0) 586 pt = _add("-0", pt, ptlim); 587 else pt = _conv(lead, "%02d", pt, ptlim); 588 } 589 if (convert_yy) 590 pt = _conv(((trail < 0) ? -trail : trail), "%02d", pt, ptlim); 591 return pt; 592 } 593