strftime.c revision 193817
1/* 2 * Copyright (c) 1989 The Regents of the University of California. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms are permitted 6 * provided that the above copyright notice and this paragraph are 7 * duplicated in all such forms and that any documentation, 8 * advertising materials, and other materials related to such 9 * distribution and use acknowledge that the software was developed 10 * by the University of California, Berkeley. The name of the 11 * University may not be used to endorse or promote products derived 12 * from this software without specific prior written permission. 13 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 14 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 15 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 16 */ 17 18#ifndef lint 19#ifndef NOID 20static const char elsieid[] = "@(#)strftime.3 8.3"; 21/* 22** Based on the UCB version with the ID appearing below. 23** This is ANSIish only when "multibyte character == plain character". 24*/ 25#endif /* !defined NOID */ 26#endif /* !defined lint */ 27 28#include "namespace.h" 29#include "private.h" 30 31#if defined(LIBC_SCCS) && !defined(lint) 32static const char sccsid[] = "@(#)strftime.c 5.4 (Berkeley) 3/14/89"; 33#endif /* LIBC_SCCS and not lint */ 34#include <sys/cdefs.h> 35__FBSDID("$FreeBSD: head/lib/libc/stdtime/strftime.c 193817 2009-06-09 09:02:58Z delphij $"); 36 37#include "tzfile.h" 38#include <fcntl.h> 39#include <sys/stat.h> 40#include "un-namespace.h" 41#include "timelocal.h" 42 43static char * _add(const char *, char *, const char *); 44static char * _conv(int, const char *, char *, const char *); 45static char * _fmt(const char *, const struct tm *, char *, const char *, 46 int *); 47static char * _yconv(int, int, int, int, char *, const char *); 48 49extern char * tzname[]; 50 51#ifndef YEAR_2000_NAME 52#define YEAR_2000_NAME "CHECK_STRFTIME_FORMATS_FOR_TWO_DIGIT_YEARS" 53#endif /* !defined YEAR_2000_NAME */ 54 55#define IN_NONE 0 56#define IN_SOME 1 57#define IN_THIS 2 58#define IN_ALL 3 59 60#define PAD_DEFAULT 0 61#define PAD_LESS 1 62#define PAD_SPACE 2 63#define PAD_ZERO 3 64 65static const char* fmt_padding[][4] = { 66 /* DEFAULT, LESS, SPACE, ZERO */ 67#define PAD_FMT_MONTHDAY 0 68#define PAD_FMT_HMS 0 69#define PAD_FMT_CENTURY 0 70#define PAD_FMT_SHORTYEAR 0 71#define PAD_FMT_MONTH 0 72#define PAD_FMT_WEEKOFYEAR 0 73#define PAD_FMT_DAYOFMONTH 0 74 { "%02d", "%d", "%2d", "%02d" }, 75#define PAD_FMT_SDAYOFMONTH 1 76#define PAD_FMT_SHMS 1 77 { "%2d", "%d", "%2d", "%02d" }, 78#define PAD_FMT_DAYOFYEAR 2 79 { "%03d", "%d", "%3d", "%03d" }, 80#define PAD_FMT_YEAR 3 81 { "%04d", "%d", "%4d", "%04d" } 82}; 83 84size_t 85strftime(char * __restrict s, size_t maxsize, const char * __restrict format, 86 const struct tm * __restrict t) 87{ 88 char * p; 89 int warn; 90 91 tzset(); 92 warn = IN_NONE; 93 p = _fmt(((format == NULL) ? "%c" : format), t, s, s + maxsize, &warn); 94#ifndef NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU 95 if (warn != IN_NONE && getenv(YEAR_2000_NAME) != NULL) { 96 (void) fprintf(stderr, "\n"); 97 if (format == NULL) 98 (void) fprintf(stderr, "NULL strftime format "); 99 else (void) fprintf(stderr, "strftime format \"%s\" ", 100 format); 101 (void) fprintf(stderr, "yields only two digits of years in "); 102 if (warn == IN_SOME) 103 (void) fprintf(stderr, "some locales"); 104 else if (warn == IN_THIS) 105 (void) fprintf(stderr, "the current locale"); 106 else (void) fprintf(stderr, "all locales"); 107 (void) fprintf(stderr, "\n"); 108 } 109#endif /* !defined NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU */ 110 if (p == s + maxsize) 111 return 0; 112 *p = '\0'; 113 return p - s; 114} 115 116static char * 117_fmt(format, t, pt, ptlim, warnp) 118const char * format; 119const struct tm * const t; 120char * pt; 121const char * const ptlim; 122int * warnp; 123{ 124 int Ealternative, Oalternative, PadIndex; 125 struct lc_time_T *tptr = __get_current_time_locale(); 126 127 for ( ; *format; ++format) { 128 if (*format == '%') { 129 Ealternative = 0; 130 Oalternative = 0; 131 PadIndex = PAD_DEFAULT; 132label: 133 switch (*++format) { 134 case '\0': 135 --format; 136 break; 137 case 'A': 138 pt = _add((t->tm_wday < 0 || 139 t->tm_wday >= DAYSPERWEEK) ? 140 "?" : tptr->weekday[t->tm_wday], 141 pt, ptlim); 142 continue; 143 case 'a': 144 pt = _add((t->tm_wday < 0 || 145 t->tm_wday >= DAYSPERWEEK) ? 146 "?" : tptr->wday[t->tm_wday], 147 pt, ptlim); 148 continue; 149 case 'B': 150 pt = _add((t->tm_mon < 0 || 151 t->tm_mon >= MONSPERYEAR) ? 152 "?" : (Oalternative ? tptr->alt_month : 153 tptr->month)[t->tm_mon], 154 pt, ptlim); 155 continue; 156 case 'b': 157 case 'h': 158 pt = _add((t->tm_mon < 0 || 159 t->tm_mon >= MONSPERYEAR) ? 160 "?" : tptr->mon[t->tm_mon], 161 pt, ptlim); 162 continue; 163 case 'C': 164 /* 165 ** %C used to do a... 166 ** _fmt("%a %b %e %X %Y", t); 167 ** ...whereas now POSIX 1003.2 calls for 168 ** something completely different. 169 ** (ado, 1993-05-24) 170 */ 171 pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 0, 172 pt, ptlim); 173 continue; 174 case 'c': 175 { 176 int warn2 = IN_SOME; 177 178 pt = _fmt(tptr->c_fmt, t, pt, ptlim, &warn2); 179 if (warn2 == IN_ALL) 180 warn2 = IN_THIS; 181 if (warn2 > *warnp) 182 *warnp = warn2; 183 } 184 continue; 185 case 'D': 186 pt = _fmt("%m/%d/%y", t, pt, ptlim, warnp); 187 continue; 188 case 'd': 189 pt = _conv(t->tm_mday, fmt_padding[PAD_FMT_DAYOFMONTH][PadIndex], 190 pt, ptlim); 191 continue; 192 case 'E': 193 if (Ealternative || Oalternative) 194 break; 195 Ealternative++; 196 goto label; 197 case 'O': 198 /* 199 ** C99 locale modifiers. 200 ** The sequences 201 ** %Ec %EC %Ex %EX %Ey %EY 202 ** %Od %oe %OH %OI %Om %OM 203 ** %OS %Ou %OU %OV %Ow %OW %Oy 204 ** are supposed to provide alternate 205 ** representations. 206 ** 207 ** FreeBSD extension 208 ** %OB 209 */ 210 if (Ealternative || Oalternative) 211 break; 212 Oalternative++; 213 goto label; 214 case 'e': 215 pt = _conv(t->tm_mday, 216 fmt_padding[PAD_FMT_SDAYOFMONTH][PadIndex], pt, ptlim); 217 continue; 218 case 'F': 219 pt = _fmt("%Y-%m-%d", t, pt, ptlim, warnp); 220 continue; 221 case 'H': 222 pt = _conv(t->tm_hour, fmt_padding[PAD_FMT_HMS][PadIndex], 223 pt, ptlim); 224 continue; 225 case 'I': 226 pt = _conv((t->tm_hour % 12) ? 227 (t->tm_hour % 12) : 12, 228 fmt_padding[PAD_FMT_HMS][PadIndex], pt, ptlim); 229 continue; 230 case 'j': 231 pt = _conv(t->tm_yday + 1, 232 fmt_padding[PAD_FMT_DAYOFYEAR][PadIndex], pt, ptlim); 233 continue; 234 case 'k': 235 /* 236 ** This used to be... 237 ** _conv(t->tm_hour % 12 ? 238 ** t->tm_hour % 12 : 12, 2, ' '); 239 ** ...and has been changed to the below to 240 ** match SunOS 4.1.1 and Arnold Robbins' 241 ** strftime version 3.0. That is, "%k" and 242 ** "%l" have been swapped. 243 ** (ado, 1993-05-24) 244 */ 245 pt = _conv(t->tm_hour, fmt_padding[PAD_FMT_SHMS][PadIndex], 246 pt, ptlim); 247 continue; 248#ifdef KITCHEN_SINK 249 case 'K': 250 /* 251 ** After all this time, still unclaimed! 252 */ 253 pt = _add("kitchen sink", pt, ptlim); 254 continue; 255#endif /* defined KITCHEN_SINK */ 256 case 'l': 257 /* 258 ** This used to be... 259 ** _conv(t->tm_hour, 2, ' '); 260 ** ...and has been changed to the below to 261 ** match SunOS 4.1.1 and Arnold Robbin's 262 ** strftime version 3.0. That is, "%k" and 263 ** "%l" have been swapped. 264 ** (ado, 1993-05-24) 265 */ 266 pt = _conv((t->tm_hour % 12) ? 267 (t->tm_hour % 12) : 12, 268 fmt_padding[PAD_FMT_SHMS][PadIndex], pt, ptlim); 269 continue; 270 case 'M': 271 pt = _conv(t->tm_min, fmt_padding[PAD_FMT_HMS][PadIndex], 272 pt, ptlim); 273 continue; 274 case 'm': 275 pt = _conv(t->tm_mon + 1, 276 fmt_padding[PAD_FMT_MONTH][PadIndex], pt, ptlim); 277 continue; 278 case 'n': 279 pt = _add("\n", pt, ptlim); 280 continue; 281 case 'p': 282 pt = _add((t->tm_hour >= (HOURSPERDAY / 2)) ? 283 tptr->pm : 284 tptr->am, 285 pt, ptlim); 286 continue; 287 case 'R': 288 pt = _fmt("%H:%M", t, pt, ptlim, warnp); 289 continue; 290 case 'r': 291 pt = _fmt(tptr->ampm_fmt, t, pt, ptlim, 292 warnp); 293 continue; 294 case 'S': 295 pt = _conv(t->tm_sec, fmt_padding[PAD_FMT_HMS][PadIndex], 296 pt, ptlim); 297 continue; 298 case 's': 299 { 300 struct tm tm; 301 char buf[INT_STRLEN_MAXIMUM( 302 time_t) + 1]; 303 time_t mkt; 304 305 tm = *t; 306 mkt = mktime(&tm); 307 if (TYPE_SIGNED(time_t)) 308 (void) sprintf(buf, "%ld", 309 (long) mkt); 310 else (void) sprintf(buf, "%lu", 311 (unsigned long) mkt); 312 pt = _add(buf, pt, ptlim); 313 } 314 continue; 315 case 'T': 316 pt = _fmt("%H:%M:%S", t, pt, ptlim, warnp); 317 continue; 318 case 't': 319 pt = _add("\t", pt, ptlim); 320 continue; 321 case 'U': 322 pt = _conv((t->tm_yday + DAYSPERWEEK - 323 t->tm_wday) / DAYSPERWEEK, 324 fmt_padding[PAD_FMT_WEEKOFYEAR][PadIndex], pt, ptlim); 325 continue; 326 case 'u': 327 /* 328 ** From Arnold Robbins' strftime version 3.0: 329 ** "ISO 8601: Weekday as a decimal number 330 ** [1 (Monday) - 7]" 331 ** (ado, 1993-05-24) 332 */ 333 pt = _conv((t->tm_wday == 0) ? 334 DAYSPERWEEK : t->tm_wday, 335 "%d", pt, ptlim); 336 continue; 337 case 'V': /* ISO 8601 week number */ 338 case 'G': /* ISO 8601 year (four digits) */ 339 case 'g': /* ISO 8601 year (two digits) */ 340/* 341** From Arnold Robbins' strftime version 3.0: "the week number of the 342** year (the first Monday as the first day of week 1) as a decimal number 343** (01-53)." 344** (ado, 1993-05-24) 345** 346** From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn: 347** "Week 01 of a year is per definition the first week which has the 348** Thursday in this year, which is equivalent to the week which contains 349** the fourth day of January. In other words, the first week of a new year 350** is the week which has the majority of its days in the new year. Week 01 351** might also contain days from the previous year and the week before week 352** 01 of a year is the last week (52 or 53) of the previous year even if 353** it contains days from the new year. A week starts with Monday (day 1) 354** and ends with Sunday (day 7). For example, the first week of the year 355** 1997 lasts from 1996-12-30 to 1997-01-05..." 356** (ado, 1996-01-02) 357*/ 358 { 359 int year; 360 int base; 361 int yday; 362 int wday; 363 int w; 364 365 year = t->tm_year; 366 base = TM_YEAR_BASE; 367 yday = t->tm_yday; 368 wday = t->tm_wday; 369 for ( ; ; ) { 370 int len; 371 int bot; 372 int top; 373 374 len = isleap_sum(year, base) ? 375 DAYSPERLYEAR : 376 DAYSPERNYEAR; 377 /* 378 ** What yday (-3 ... 3) does 379 ** the ISO year begin on? 380 */ 381 bot = ((yday + 11 - wday) % 382 DAYSPERWEEK) - 3; 383 /* 384 ** What yday does the NEXT 385 ** ISO year begin on? 386 */ 387 top = bot - 388 (len % DAYSPERWEEK); 389 if (top < -3) 390 top += DAYSPERWEEK; 391 top += len; 392 if (yday >= top) { 393 ++base; 394 w = 1; 395 break; 396 } 397 if (yday >= bot) { 398 w = 1 + ((yday - bot) / 399 DAYSPERWEEK); 400 break; 401 } 402 --base; 403 yday += isleap_sum(year, base) ? 404 DAYSPERLYEAR : 405 DAYSPERNYEAR; 406 } 407#ifdef XPG4_1994_04_09 408 if ((w == 52 && 409 t->tm_mon == TM_JANUARY) || 410 (w == 1 && 411 t->tm_mon == TM_DECEMBER)) 412 w = 53; 413#endif /* defined XPG4_1994_04_09 */ 414 if (*format == 'V') 415 pt = _conv(w, fmt_padding[PAD_FMT_WEEKOFYEAR][PadIndex], 416 pt, ptlim); 417 else if (*format == 'g') { 418 *warnp = IN_ALL; 419 pt = _yconv(year, base, 0, 1, 420 pt, ptlim); 421 } else pt = _yconv(year, base, 1, 1, 422 pt, ptlim); 423 } 424 continue; 425 case 'v': 426 /* 427 ** From Arnold Robbins' strftime version 3.0: 428 ** "date as dd-bbb-YYYY" 429 ** (ado, 1993-05-24) 430 */ 431 pt = _fmt("%e-%b-%Y", t, pt, ptlim, warnp); 432 continue; 433 case 'W': 434 pt = _conv((t->tm_yday + DAYSPERWEEK - 435 (t->tm_wday ? 436 (t->tm_wday - 1) : 437 (DAYSPERWEEK - 1))) / DAYSPERWEEK, 438 fmt_padding[PAD_FMT_WEEKOFYEAR][PadIndex], pt, ptlim); 439 continue; 440 case 'w': 441 pt = _conv(t->tm_wday, "%d", pt, ptlim); 442 continue; 443 case 'X': 444 pt = _fmt(tptr->X_fmt, t, pt, ptlim, warnp); 445 continue; 446 case 'x': 447 { 448 int warn2 = IN_SOME; 449 450 pt = _fmt(tptr->x_fmt, t, pt, ptlim, &warn2); 451 if (warn2 == IN_ALL) 452 warn2 = IN_THIS; 453 if (warn2 > *warnp) 454 *warnp = warn2; 455 } 456 continue; 457 case 'y': 458 *warnp = IN_ALL; 459 pt = _yconv(t->tm_year, TM_YEAR_BASE, 0, 1, 460 pt, ptlim); 461 continue; 462 case 'Y': 463 pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 1, 464 pt, ptlim); 465 continue; 466 case 'Z': 467#ifdef TM_ZONE 468 if (t->TM_ZONE != NULL) 469 pt = _add(t->TM_ZONE, pt, ptlim); 470 else 471#endif /* defined TM_ZONE */ 472 if (t->tm_isdst >= 0) 473 pt = _add(tzname[t->tm_isdst != 0], 474 pt, ptlim); 475 /* 476 ** C99 says that %Z must be replaced by the 477 ** empty string if the time zone is not 478 ** determinable. 479 */ 480 continue; 481 case 'z': 482 { 483 int diff; 484 char const * sign; 485 486 if (t->tm_isdst < 0) 487 continue; 488#ifdef TM_GMTOFF 489 diff = t->TM_GMTOFF; 490#else /* !defined TM_GMTOFF */ 491 /* 492 ** C99 says that the UTC offset must 493 ** be computed by looking only at 494 ** tm_isdst. This requirement is 495 ** incorrect, since it means the code 496 ** must rely on magic (in this case 497 ** altzone and timezone), and the 498 ** magic might not have the correct 499 ** offset. Doing things correctly is 500 ** tricky and requires disobeying C99; 501 ** see GNU C strftime for details. 502 ** For now, punt and conform to the 503 ** standard, even though it's incorrect. 504 ** 505 ** C99 says that %z must be replaced by the 506 ** empty string if the time zone is not 507 ** determinable, so output nothing if the 508 ** appropriate variables are not available. 509 */ 510 if (t->tm_isdst == 0) 511#ifdef USG_COMPAT 512 diff = -timezone; 513#else /* !defined USG_COMPAT */ 514 continue; 515#endif /* !defined USG_COMPAT */ 516 else 517#ifdef ALTZONE 518 diff = -altzone; 519#else /* !defined ALTZONE */ 520 continue; 521#endif /* !defined ALTZONE */ 522#endif /* !defined TM_GMTOFF */ 523 if (diff < 0) { 524 sign = "-"; 525 diff = -diff; 526 } else sign = "+"; 527 pt = _add(sign, pt, ptlim); 528 diff /= SECSPERMIN; 529 diff = (diff / MINSPERHOUR) * 100 + 530 (diff % MINSPERHOUR); 531 pt = _conv(diff, 532 fmt_padding[PAD_FMT_YEAR][PadIndex], pt, ptlim); 533 } 534 continue; 535 case '+': 536 pt = _fmt(tptr->date_fmt, t, pt, ptlim, 537 warnp); 538 continue; 539 case '-': 540 if (PadIndex != PAD_DEFAULT) 541 break; 542 PadIndex = PAD_LESS; 543 goto label; 544 case '_': 545 if (PadIndex != PAD_DEFAULT) 546 break; 547 PadIndex = PAD_SPACE; 548 goto label; 549 case '0': 550 if (PadIndex != PAD_DEFAULT) 551 break; 552 PadIndex = PAD_ZERO; 553 goto label; 554 case '%': 555 /* 556 ** X311J/88-090 (4.12.3.5): if conversion char is 557 ** undefined, behavior is undefined. Print out the 558 ** character itself as printf(3) also does. 559 */ 560 default: 561 break; 562 } 563 } 564 if (pt == ptlim) 565 break; 566 *pt++ = *format; 567 } 568 return pt; 569} 570 571static char * 572_conv(n, format, pt, ptlim) 573const int n; 574const char * const format; 575char * const pt; 576const char * const ptlim; 577{ 578 char buf[INT_STRLEN_MAXIMUM(int) + 1]; 579 580 (void) sprintf(buf, format, n); 581 return _add(buf, pt, ptlim); 582} 583 584static char * 585_add(str, pt, ptlim) 586const char * str; 587char * pt; 588const char * const ptlim; 589{ 590 while (pt < ptlim && (*pt = *str++) != '\0') 591 ++pt; 592 return pt; 593} 594 595/* 596** POSIX and the C Standard are unclear or inconsistent about 597** what %C and %y do if the year is negative or exceeds 9999. 598** Use the convention that %C concatenated with %y yields the 599** same output as %Y, and that %Y contains at least 4 bytes, 600** with more only if necessary. 601*/ 602 603static char * 604_yconv(a, b, convert_top, convert_yy, pt, ptlim) 605const int a; 606const int b; 607const int convert_top; 608const int convert_yy; 609char * pt; 610const char * const ptlim; 611{ 612 register int lead; 613 register int trail; 614 615#define DIVISOR 100 616 trail = a % DIVISOR + b % DIVISOR; 617 lead = a / DIVISOR + b / DIVISOR + trail / DIVISOR; 618 trail %= DIVISOR; 619 if (trail < 0 && lead > 0) { 620 trail += DIVISOR; 621 --lead; 622 } else if (lead < 0 && trail > 0) { 623 trail -= DIVISOR; 624 ++lead; 625 } 626 if (convert_top) { 627 if (lead == 0 && trail < 0) 628 pt = _add("-0", pt, ptlim); 629 else pt = _conv(lead, "%02d", pt, ptlim); 630 } 631 if (convert_yy) 632 pt = _conv(((trail < 0) ? -trail : trail), "%02d", pt, ptlim); 633 return pt; 634} 635