1 /* 2 * Copyright (c) 1989 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * Copyright (c) 2011 The FreeBSD Foundation 6 * All rights reserved. 7 * Portions of this software were developed by David Chisnall 8 * under sponsorship from the FreeBSD Foundation. 9 * 10 * Redistribution and use in source and binary forms are permitted 11 * provided that the above copyright notice and this paragraph are 12 * duplicated in all such forms and that any documentation, 13 * advertising materials, and other materials related to such 14 * distribution and use acknowledge that the software was developed 15 * by the University of California, Berkeley. The name of the 16 * University may not be used to endorse or promote products derived 17 * from this software without specific prior written permission. 18 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 19 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 20 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 21 * 22 * @(#)strftime.c 5.4 (Berkeley) 3/14/89 23 * $FreeBSD: head/lib/libc/stdtime/strftime.c 237211 2012-06-17 21:40:13Z jilles $ 24 */ 25 26 27 #include "namespace.h" 28 #include "private.h" 29 30 #include "tzfile.h" 31 #include <fcntl.h> 32 #include <sys/stat.h> 33 #include "un-namespace.h" 34 #include "timelocal.h" 35 36 static char * _add(const char *, char *, const char *); 37 static char * _conv(int, const char *, char *, const char *); 38 static char * _fmt(const char *, const struct tm *, char *, const char *, 39 int *, locale_t); 40 static char * _yconv(int, int, int, int, char *, const char *); 41 42 extern char * tzname[]; 43 44 #ifndef YEAR_2000_NAME 45 #define YEAR_2000_NAME "CHECK_STRFTIME_FORMATS_FOR_TWO_DIGIT_YEARS" 46 #endif /* !defined YEAR_2000_NAME */ 47 48 #define IN_NONE 0 49 #define IN_SOME 1 50 #define IN_THIS 2 51 #define IN_ALL 3 52 53 #define PAD_DEFAULT 0 54 #define PAD_LESS 1 55 #define PAD_SPACE 2 56 #define PAD_ZERO 3 57 58 static const char fmt_padding[][4][5] = { 59 /* DEFAULT, LESS, SPACE, ZERO */ 60 #define PAD_FMT_MONTHDAY 0 61 #define PAD_FMT_HMS 0 62 #define PAD_FMT_CENTURY 0 63 #define PAD_FMT_SHORTYEAR 0 64 #define PAD_FMT_MONTH 0 65 #define PAD_FMT_WEEKOFYEAR 0 66 #define PAD_FMT_DAYOFMONTH 0 67 { "%02d", "%d", "%2d", "%02d" }, 68 #define PAD_FMT_SDAYOFMONTH 1 69 #define PAD_FMT_SHMS 1 70 { "%2d", "%d", "%2d", "%02d" }, 71 #define PAD_FMT_DAYOFYEAR 2 72 { "%03d", "%d", "%3d", "%03d" }, 73 #define PAD_FMT_YEAR 3 74 { "%04d", "%d", "%4d", "%04d" } 75 }; 76 77 size_t 78 strftime_l(char * __restrict s, size_t maxsize, const char * __restrict format, 79 const struct tm * __restrict t, locale_t loc) 80 { 81 char * p; 82 int warn; 83 FIX_LOCALE(loc); 84 85 tzset(); 86 warn = IN_NONE; 87 p = _fmt(((format == NULL) ? "%c" : format), t, s, s + maxsize, &warn, loc); 88 #ifndef NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU 89 if (warn != IN_NONE && getenv(YEAR_2000_NAME) != NULL) { 90 (void) fprintf_l(stderr, loc, "\n"); 91 if (format == NULL) 92 (void) fprintf_l(stderr, loc, "NULL strftime format "); 93 else (void) fprintf_l(stderr, loc, "strftime format \"%s\" ", 94 format); 95 (void) fprintf_l(stderr, loc, "yields only two digits of years in "); 96 if (warn == IN_SOME) 97 (void) fprintf_l(stderr, loc, "some locales"); 98 else if (warn == IN_THIS) 99 (void) fprintf_l(stderr, loc, "the current locale"); 100 else (void) fprintf_l(stderr, loc, "all locales"); 101 (void) fprintf_l(stderr, loc, "\n"); 102 } 103 #endif /* !defined NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU */ 104 if (p == s + maxsize) 105 return 0; 106 *p = '\0'; 107 return p - s; 108 } 109 110 size_t 111 strftime(char * __restrict s, size_t maxsize, const char * __restrict format, 112 const struct tm * __restrict t) 113 { 114 return strftime_l(s, maxsize, format, t, __get_locale()); 115 } 116 117 static char * 118 _fmt(const char *format, const struct tm * const t, char *pt, 119 const char * const ptlim, int *warnp, locale_t loc) 120 { 121 int Ealternative, Oalternative, PadIndex; 122 struct lc_time_T *tptr = __get_current_time_locale(loc); 123 124 for ( ; *format; ++format) { 125 if (*format == '%') { 126 Ealternative = 0; 127 Oalternative = 0; 128 PadIndex = PAD_DEFAULT; 129 label: 130 switch (*++format) { 131 case '\0': 132 --format; 133 break; 134 case 'A': 135 pt = _add((t->tm_wday < 0 || 136 t->tm_wday >= DAYSPERWEEK) ? 137 "?" : tptr->weekday[t->tm_wday], 138 pt, ptlim); 139 continue; 140 case 'a': 141 pt = _add((t->tm_wday < 0 || 142 t->tm_wday >= DAYSPERWEEK) ? 143 "?" : tptr->wday[t->tm_wday], 144 pt, ptlim); 145 continue; 146 case 'B': 147 pt = _add((t->tm_mon < 0 || 148 t->tm_mon >= MONSPERYEAR) ? 149 "?" : (Oalternative ? tptr->alt_month : 150 tptr->month)[t->tm_mon], 151 pt, ptlim); 152 continue; 153 case 'b': 154 case 'h': 155 pt = _add((t->tm_mon < 0 || 156 t->tm_mon >= MONSPERYEAR) ? 157 "?" : tptr->mon[t->tm_mon], 158 pt, ptlim); 159 continue; 160 case 'C': 161 /* 162 ** %C used to do a... 163 ** _fmt("%a %b %e %X %Y", t); 164 ** ...whereas now POSIX 1003.2 calls for 165 ** something completely different. 166 ** (ado, 1993-05-24) 167 */ 168 pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 0, 169 pt, ptlim); 170 continue; 171 case 'c': 172 { 173 int warn2 = IN_SOME; 174 175 pt = _fmt(tptr->c_fmt, t, pt, ptlim, &warn2, loc); 176 if (warn2 == IN_ALL) 177 warn2 = IN_THIS; 178 if (warn2 > *warnp) 179 *warnp = warn2; 180 } 181 continue; 182 case 'D': 183 pt = _fmt("%m/%d/%y", t, pt, ptlim, warnp, loc); 184 continue; 185 case 'd': 186 pt = _conv(t->tm_mday, fmt_padding[PAD_FMT_DAYOFMONTH][PadIndex], 187 pt, ptlim); 188 continue; 189 case 'E': 190 if (Ealternative || Oalternative) 191 break; 192 Ealternative++; 193 goto label; 194 case 'O': 195 /* 196 ** C99 locale modifiers. 197 ** The sequences 198 ** %Ec %EC %Ex %EX %Ey %EY 199 ** %Od %oe %OH %OI %Om %OM 200 ** %OS %Ou %OU %OV %Ow %OW %Oy 201 ** are supposed to provide alternate 202 ** representations. 203 ** 204 ** FreeBSD extension 205 ** %OB 206 */ 207 if (Ealternative || Oalternative) 208 break; 209 Oalternative++; 210 goto label; 211 case 'e': 212 pt = _conv(t->tm_mday, 213 fmt_padding[PAD_FMT_SDAYOFMONTH][PadIndex], pt, ptlim); 214 continue; 215 case 'F': 216 pt = _fmt("%Y-%m-%d", t, pt, ptlim, warnp, loc); 217 continue; 218 case 'H': 219 pt = _conv(t->tm_hour, fmt_padding[PAD_FMT_HMS][PadIndex], 220 pt, ptlim); 221 continue; 222 case 'I': 223 pt = _conv((t->tm_hour % 12) ? 224 (t->tm_hour % 12) : 12, 225 fmt_padding[PAD_FMT_HMS][PadIndex], pt, ptlim); 226 continue; 227 case 'j': 228 pt = _conv(t->tm_yday + 1, 229 fmt_padding[PAD_FMT_DAYOFYEAR][PadIndex], pt, ptlim); 230 continue; 231 case 'k': 232 /* 233 ** This used to be... 234 ** _conv(t->tm_hour % 12 ? 235 ** t->tm_hour % 12 : 12, 2, ' '); 236 ** ...and has been changed to the below to 237 ** match SunOS 4.1.1 and Arnold Robbins' 238 ** strftime version 3.0. That is, "%k" and 239 ** "%l" have been swapped. 240 ** (ado, 1993-05-24) 241 */ 242 pt = _conv(t->tm_hour, fmt_padding[PAD_FMT_SHMS][PadIndex], 243 pt, ptlim); 244 continue; 245 #ifdef KITCHEN_SINK 246 case 'K': 247 /* 248 ** After all this time, still unclaimed! 249 */ 250 pt = _add("kitchen sink", pt, ptlim); 251 continue; 252 #endif /* defined KITCHEN_SINK */ 253 case 'l': 254 /* 255 ** This used to be... 256 ** _conv(t->tm_hour, 2, ' '); 257 ** ...and has been changed to the below to 258 ** match SunOS 4.1.1 and Arnold Robbin's 259 ** strftime version 3.0. That is, "%k" and 260 ** "%l" have been swapped. 261 ** (ado, 1993-05-24) 262 */ 263 pt = _conv((t->tm_hour % 12) ? 264 (t->tm_hour % 12) : 12, 265 fmt_padding[PAD_FMT_SHMS][PadIndex], pt, ptlim); 266 continue; 267 case 'M': 268 pt = _conv(t->tm_min, fmt_padding[PAD_FMT_HMS][PadIndex], 269 pt, ptlim); 270 continue; 271 case 'm': 272 pt = _conv(t->tm_mon + 1, 273 fmt_padding[PAD_FMT_MONTH][PadIndex], pt, ptlim); 274 continue; 275 case 'n': 276 pt = _add("\n", pt, ptlim); 277 continue; 278 case 'p': 279 pt = _add((t->tm_hour >= (HOURSPERDAY / 2)) ? 280 tptr->pm : 281 tptr->am, 282 pt, ptlim); 283 continue; 284 case 'R': 285 pt = _fmt("%H:%M", t, pt, ptlim, warnp, loc); 286 continue; 287 case 'r': 288 pt = _fmt(tptr->ampm_fmt, t, pt, ptlim, 289 warnp, loc); 290 continue; 291 case 'S': 292 pt = _conv(t->tm_sec, fmt_padding[PAD_FMT_HMS][PadIndex], 293 pt, ptlim); 294 continue; 295 case 's': 296 { 297 struct tm tm; 298 char buf[INT_STRLEN_MAXIMUM( 299 time_t) + 1]; 300 time_t mkt; 301 302 tm = *t; 303 mkt = mktime(&tm); 304 if (TYPE_SIGNED(time_t)) 305 (void) sprintf(buf, "%ld", 306 (long) mkt); 307 else (void) sprintf(buf, "%lu", 308 (unsigned long) mkt); 309 pt = _add(buf, pt, ptlim); 310 } 311 continue; 312 case 'T': 313 pt = _fmt("%H:%M:%S", t, pt, ptlim, warnp, loc); 314 continue; 315 case 't': 316 pt = _add("\t", pt, ptlim); 317 continue; 318 case 'U': 319 pt = _conv((t->tm_yday + DAYSPERWEEK - 320 t->tm_wday) / DAYSPERWEEK, 321 fmt_padding[PAD_FMT_WEEKOFYEAR][PadIndex], pt, ptlim); 322 continue; 323 case 'u': 324 /* 325 ** From Arnold Robbins' strftime version 3.0: 326 ** "ISO 8601: Weekday as a decimal number 327 ** [1 (Monday) - 7]" 328 ** (ado, 1993-05-24) 329 */ 330 pt = _conv((t->tm_wday == 0) ? 331 DAYSPERWEEK : t->tm_wday, 332 "%d", pt, ptlim); 333 continue; 334 case 'V': /* ISO 8601 week number */ 335 case 'G': /* ISO 8601 year (four digits) */ 336 case 'g': /* ISO 8601 year (two digits) */ 337 /* 338 ** From Arnold Robbins' strftime version 3.0: "the week number of the 339 ** year (the first Monday as the first day of week 1) as a decimal number 340 ** (01-53)." 341 ** (ado, 1993-05-24) 342 ** 343 ** From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn: 344 ** "Week 01 of a year is per definition the first week which has the 345 ** Thursday in this year, which is equivalent to the week which contains 346 ** the fourth day of January. In other words, the first week of a new year 347 ** is the week which has the majority of its days in the new year. Week 01 348 ** might also contain days from the previous year and the week before week 349 ** 01 of a year is the last week (52 or 53) of the previous year even if 350 ** it contains days from the new year. A week starts with Monday (day 1) 351 ** and ends with Sunday (day 7). For example, the first week of the year 352 ** 1997 lasts from 1996-12-30 to 1997-01-05..." 353 ** (ado, 1996-01-02) 354 */ 355 { 356 int year; 357 int base; 358 int yday; 359 int wday; 360 int w; 361 362 year = t->tm_year; 363 base = TM_YEAR_BASE; 364 yday = t->tm_yday; 365 wday = t->tm_wday; 366 for ( ; ; ) { 367 int len; 368 int bot; 369 int top; 370 371 len = isleap_sum(year, base) ? 372 DAYSPERLYEAR : 373 DAYSPERNYEAR; 374 /* 375 ** What yday (-3 ... 3) does 376 ** the ISO year begin on? 377 */ 378 bot = ((yday + 11 - wday) % 379 DAYSPERWEEK) - 3; 380 /* 381 ** What yday does the NEXT 382 ** ISO year begin on? 383 */ 384 top = bot - 385 (len % DAYSPERWEEK); 386 if (top < -3) 387 top += DAYSPERWEEK; 388 top += len; 389 if (yday >= top) { 390 ++base; 391 w = 1; 392 break; 393 } 394 if (yday >= bot) { 395 w = 1 + ((yday - bot) / 396 DAYSPERWEEK); 397 break; 398 } 399 --base; 400 yday += isleap_sum(year, base) ? 401 DAYSPERLYEAR : 402 DAYSPERNYEAR; 403 } 404 #ifdef XPG4_1994_04_09 405 if ((w == 52 && 406 t->tm_mon == TM_JANUARY) || 407 (w == 1 && 408 t->tm_mon == TM_DECEMBER)) 409 w = 53; 410 #endif /* defined XPG4_1994_04_09 */ 411 if (*format == 'V') 412 pt = _conv(w, fmt_padding[PAD_FMT_WEEKOFYEAR][PadIndex], 413 pt, ptlim); 414 else if (*format == 'g') { 415 *warnp = IN_ALL; 416 pt = _yconv(year, base, 0, 1, 417 pt, ptlim); 418 } else pt = _yconv(year, base, 1, 1, 419 pt, ptlim); 420 } 421 continue; 422 case 'v': 423 /* 424 ** From Arnold Robbins' strftime version 3.0: 425 ** "date as dd-bbb-YYYY" 426 ** (ado, 1993-05-24) 427 */ 428 pt = _fmt("%e-%b-%Y", t, pt, ptlim, warnp, loc); 429 continue; 430 case 'W': 431 pt = _conv((t->tm_yday + DAYSPERWEEK - 432 (t->tm_wday ? 433 (t->tm_wday - 1) : 434 (DAYSPERWEEK - 1))) / DAYSPERWEEK, 435 fmt_padding[PAD_FMT_WEEKOFYEAR][PadIndex], pt, ptlim); 436 continue; 437 case 'w': 438 pt = _conv(t->tm_wday, "%d", pt, ptlim); 439 continue; 440 case 'X': 441 pt = _fmt(tptr->X_fmt, t, pt, ptlim, warnp, loc); 442 continue; 443 case 'x': 444 { 445 int warn2 = IN_SOME; 446 447 pt = _fmt(tptr->x_fmt, t, pt, ptlim, &warn2, loc); 448 if (warn2 == IN_ALL) 449 warn2 = IN_THIS; 450 if (warn2 > *warnp) 451 *warnp = warn2; 452 } 453 continue; 454 case 'y': 455 *warnp = IN_ALL; 456 pt = _yconv(t->tm_year, TM_YEAR_BASE, 0, 1, 457 pt, ptlim); 458 continue; 459 case 'Y': 460 pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 1, 461 pt, ptlim); 462 continue; 463 case 'Z': 464 #ifdef TM_ZONE 465 if (t->TM_ZONE != NULL) 466 pt = _add(t->TM_ZONE, pt, ptlim); 467 else 468 #endif /* defined TM_ZONE */ 469 if (t->tm_isdst >= 0) 470 pt = _add(tzname[t->tm_isdst != 0], 471 pt, ptlim); 472 /* 473 ** C99 says that %Z must be replaced by the 474 ** empty string if the time zone is not 475 ** determinable. 476 */ 477 continue; 478 case 'z': 479 { 480 int diff; 481 char const * sign; 482 483 if (t->tm_isdst < 0) 484 continue; 485 #ifdef TM_GMTOFF 486 diff = t->TM_GMTOFF; 487 #else /* !defined TM_GMTOFF */ 488 /* 489 ** C99 says that the UTC offset must 490 ** be computed by looking only at 491 ** tm_isdst. This requirement is 492 ** incorrect, since it means the code 493 ** must rely on magic (in this case 494 ** altzone and timezone), and the 495 ** magic might not have the correct 496 ** offset. Doing things correctly is 497 ** tricky and requires disobeying C99; 498 ** see GNU C strftime for details. 499 ** For now, punt and conform to the 500 ** standard, even though it's incorrect. 501 ** 502 ** C99 says that %z must be replaced by the 503 ** empty string if the time zone is not 504 ** determinable, so output nothing if the 505 ** appropriate variables are not available. 506 */ 507 if (t->tm_isdst == 0) 508 diff = -timezone; 509 else 510 continue; 511 #endif /* !defined TM_GMTOFF */ 512 if (diff < 0) { 513 sign = "-"; 514 diff = -diff; 515 } else sign = "+"; 516 pt = _add(sign, pt, ptlim); 517 diff /= SECSPERMIN; 518 diff = (diff / MINSPERHOUR) * 100 + 519 (diff % MINSPERHOUR); 520 pt = _conv(diff, 521 fmt_padding[PAD_FMT_YEAR][PadIndex], pt, ptlim); 522 } 523 continue; 524 case '+': 525 pt = _fmt(tptr->date_fmt, t, pt, ptlim, 526 warnp, loc); 527 continue; 528 case '-': 529 if (PadIndex != PAD_DEFAULT) 530 break; 531 PadIndex = PAD_LESS; 532 goto label; 533 case '_': 534 if (PadIndex != PAD_DEFAULT) 535 break; 536 PadIndex = PAD_SPACE; 537 goto label; 538 case '0': 539 if (PadIndex != PAD_DEFAULT) 540 break; 541 PadIndex = PAD_ZERO; 542 goto label; 543 case '%': 544 /* 545 ** X311J/88-090 (4.12.3.5): if conversion char is 546 ** undefined, behavior is undefined. Print out the 547 ** character itself as printf(3) also does. 548 */ 549 default: 550 break; 551 } 552 } 553 if (pt == ptlim) 554 break; 555 *pt++ = *format; 556 } 557 return pt; 558 } 559 560 static char * 561 _conv(const int n, const char * const format, char * const pt, 562 const char * const ptlim) 563 { 564 char buf[INT_STRLEN_MAXIMUM(int) + 1]; 565 566 (void) sprintf(buf, format, n); 567 return _add(buf, pt, ptlim); 568 } 569 570 static char * 571 _add(const char *str, char *pt, const char * const ptlim) 572 { 573 while (pt < ptlim && (*pt = *str++) != '\0') 574 ++pt; 575 return pt; 576 } 577 578 /* 579 ** POSIX and the C Standard are unclear or inconsistent about 580 ** what %C and %y do if the year is negative or exceeds 9999. 581 ** Use the convention that %C concatenated with %y yields the 582 ** same output as %Y, and that %Y contains at least 4 bytes, 583 ** with more only if necessary. 584 */ 585 586 static char * 587 _yconv(const int a, const int b, const int convert_top, const int convert_yy, 588 char *pt, const char * const ptlim) 589 { 590 int lead; 591 int trail; 592 593 #define DIVISOR 100 594 trail = a % DIVISOR + b % DIVISOR; 595 lead = a / DIVISOR + b / DIVISOR + trail / DIVISOR; 596 trail %= DIVISOR; 597 if (trail < 0 && lead > 0) { 598 trail += DIVISOR; 599 --lead; 600 } else if (lead < 0 && trail > 0) { 601 trail -= DIVISOR; 602 ++lead; 603 } 604 if (convert_top) { 605 if (lead == 0 && trail < 0) 606 pt = _add("-0", pt, ptlim); 607 else pt = _conv(lead, "%02d", pt, ptlim); 608 } 609 if (convert_yy) 610 pt = _conv(((trail < 0) ? -trail : trail), "%02d", pt, ptlim); 611 return pt; 612 } 613