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