strftime.c revision 137190
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.c 7.64"; 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 137190 2004-11-04 08:34:57Z 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 *, int *); 46 47size_t strftime(char * __restrict, size_t, const char * __restrict, 48 const struct tm * __restrict); 49 50extern char * tzname[]; 51 52#ifndef YEAR_2000_NAME 53#define YEAR_2000_NAME "CHECK_STRFTIME_FORMATS_FOR_TWO_DIGIT_YEARS" 54#endif /* !defined YEAR_2000_NAME */ 55 56 57#define IN_NONE 0 58#define IN_SOME 1 59#define IN_THIS 2 60#define IN_ALL 3 61 62#define PAD_DEFAULT 0 63#define PAD_LESS 1 64#define PAD_SPACE 2 65#define PAD_ZERO 3 66 67static const char* fmt_padding[][4] = { 68 /* DEFAULT, LESS, SPACE, ZERO */ 69#define PAD_FMT_MONTHDAY 0 70#define PAD_FMT_HMS 0 71#define PAD_FMT_CENTURY 0 72#define PAD_FMT_SHORTYEAR 0 73#define PAD_FMT_MONTH 0 74#define PAD_FMT_WEEKOFYEAR 0 75#define PAD_FMT_DAYOFMONTH 0 76 { "%02d", "%d", "%2d", "%02d" }, 77#define PAD_FMT_SDAYOFMONTH 1 78#define PAD_FMT_SHMS 1 79 { "%2d", "%d", "%2d", "%02d" }, 80#define PAD_FMT_DAYOFYEAR 2 81 { "%03d", "%d", "%3d", "%03d" }, 82#define PAD_FMT_YEAR 3 83 { "%04d", "%d", "%4d", "%04d" } 84}; 85 86size_t 87strftime(char * __restrict s, size_t maxsize, const char * __restrict format, 88 const struct tm * __restrict t) 89{ 90 char * p; 91 int warn; 92 93 tzset(); 94 warn = IN_NONE; 95 p = _fmt(((format == NULL) ? "%c" : format), t, s, s + maxsize, &warn); 96#ifndef NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU 97 if (warn != IN_NONE && getenv(YEAR_2000_NAME) != NULL) { 98 (void) fprintf(stderr, "\n"); 99 if (format == NULL) 100 (void) fprintf(stderr, "NULL strftime format "); 101 else (void) fprintf(stderr, "strftime format \"%s\" ", 102 format); 103 (void) fprintf(stderr, "yields only two digits of years in "); 104 if (warn == IN_SOME) 105 (void) fprintf(stderr, "some locales"); 106 else if (warn == IN_THIS) 107 (void) fprintf(stderr, "the current locale"); 108 else (void) fprintf(stderr, "all locales"); 109 (void) fprintf(stderr, "\n"); 110 } 111#endif /* !defined NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU */ 112 if (p == s + maxsize) 113 return 0; 114 *p = '\0'; 115 return p - s; 116} 117 118static char * 119_fmt(format, t, pt, ptlim, warnp) 120const char * format; 121const struct tm * const t; 122char * pt; 123const char * const ptlim; 124int * warnp; 125{ 126 int Ealternative, Oalternative, PadIndex; 127 struct lc_time_T *tptr = __get_current_time_locale(); 128 129 for ( ; *format; ++format) { 130 if (*format == '%') { 131 Ealternative = 0; 132 Oalternative = 0; 133 PadIndex = PAD_DEFAULT; 134label: 135 switch (*++format) { 136 case '\0': 137 --format; 138 break; 139 case 'A': 140 pt = _add((t->tm_wday < 0 || 141 t->tm_wday >= DAYSPERWEEK) ? 142 "?" : tptr->weekday[t->tm_wday], 143 pt, ptlim); 144 continue; 145 case 'a': 146 pt = _add((t->tm_wday < 0 || 147 t->tm_wday >= DAYSPERWEEK) ? 148 "?" : tptr->wday[t->tm_wday], 149 pt, ptlim); 150 continue; 151 case 'B': 152 pt = _add((t->tm_mon < 0 || 153 t->tm_mon >= MONSPERYEAR) ? 154 "?" : (Oalternative ? tptr->alt_month : 155 tptr->month)[t->tm_mon], 156 pt, ptlim); 157 continue; 158 case 'b': 159 case 'h': 160 pt = _add((t->tm_mon < 0 || 161 t->tm_mon >= MONSPERYEAR) ? 162 "?" : tptr->mon[t->tm_mon], 163 pt, ptlim); 164 continue; 165 case 'C': 166 /* 167 ** %C used to do a... 168 ** _fmt("%a %b %e %X %Y", t); 169 ** ...whereas now POSIX 1003.2 calls for 170 ** something completely different. 171 ** (ado, 1993-05-24) 172 */ 173 pt = _conv((t->tm_year + TM_YEAR_BASE) / 100, 174 fmt_padding[PAD_FMT_CENTURY][PadIndex], pt, ptlim); 175 continue; 176 case 'c': 177 { 178 int warn2 = IN_SOME; 179 180 pt = _fmt(tptr->c_fmt, t, pt, ptlim, warnp); 181 if (warn2 == IN_ALL) 182 warn2 = IN_THIS; 183 if (warn2 > *warnp) 184 *warnp = warn2; 185 } 186 continue; 187 case 'D': 188 pt = _fmt("%m/%d/%y", t, pt, ptlim, warnp); 189 continue; 190 case 'd': 191 pt = _conv(t->tm_mday, fmt_padding[PAD_FMT_DAYOFMONTH][PadIndex], 192 pt, ptlim); 193 continue; 194 case 'E': 195 if (Ealternative || Oalternative) 196 break; 197 Ealternative++; 198 goto label; 199 case 'O': 200 /* 201 ** C99 locale modifiers. 202 ** The sequences 203 ** %Ec %EC %Ex %EX %Ey %EY 204 ** %Od %oe %OH %OI %Om %OM 205 ** %OS %Ou %OU %OV %Ow %OW %Oy 206 ** are supposed to provide alternate 207 ** representations. 208 ** 209 ** FreeBSD extension 210 ** %OB 211 */ 212 if (Ealternative || Oalternative) 213 break; 214 Oalternative++; 215 goto label; 216 case 'e': 217 pt = _conv(t->tm_mday, 218 fmt_padding[PAD_FMT_SDAYOFMONTH][PadIndex], pt, ptlim); 219 continue; 220 case 'F': 221 pt = _fmt("%Y-%m-%d", t, pt, ptlim, warnp); 222 continue; 223 case 'H': 224 pt = _conv(t->tm_hour, fmt_padding[PAD_FMT_HMS][PadIndex], 225 pt, ptlim); 226 continue; 227 case 'I': 228 pt = _conv((t->tm_hour % 12) ? 229 (t->tm_hour % 12) : 12, 230 fmt_padding[PAD_FMT_HMS][PadIndex], pt, ptlim); 231 continue; 232 case 'j': 233 pt = _conv(t->tm_yday + 1, 234 fmt_padding[PAD_FMT_DAYOFYEAR][PadIndex], pt, ptlim); 235 continue; 236 case 'k': 237 /* 238 ** This used to be... 239 ** _conv(t->tm_hour % 12 ? 240 ** t->tm_hour % 12 : 12, 2, ' '); 241 ** ...and has been changed to the below to 242 ** match SunOS 4.1.1 and Arnold Robbins' 243 ** strftime version 3.0. That is, "%k" and 244 ** "%l" have been swapped. 245 ** (ado, 1993-05-24) 246 */ 247 pt = _conv(t->tm_hour, fmt_padding[PAD_FMT_SHMS][PadIndex], 248 pt, ptlim); 249 continue; 250#ifdef KITCHEN_SINK 251 case 'K': 252 /* 253 ** After all this time, still unclaimed! 254 */ 255 pt = _add("kitchen sink", pt, ptlim); 256 continue; 257#endif /* defined KITCHEN_SINK */ 258 case 'l': 259 /* 260 ** This used to be... 261 ** _conv(t->tm_hour, 2, ' '); 262 ** ...and has been changed to the below to 263 ** match SunOS 4.1.1 and Arnold Robbin's 264 ** strftime version 3.0. That is, "%k" and 265 ** "%l" have been swapped. 266 ** (ado, 1993-05-24) 267 */ 268 pt = _conv((t->tm_hour % 12) ? 269 (t->tm_hour % 12) : 12, 270 fmt_padding[PAD_FMT_SHMS][PadIndex], pt, ptlim); 271 continue; 272 case 'M': 273 pt = _conv(t->tm_min, fmt_padding[PAD_FMT_HMS][PadIndex], 274 pt, ptlim); 275 continue; 276 case 'm': 277 pt = _conv(t->tm_mon + 1, 278 fmt_padding[PAD_FMT_MONTH][PadIndex], pt, ptlim); 279 continue; 280 case 'n': 281 pt = _add("\n", pt, ptlim); 282 continue; 283 case 'p': 284 pt = _add((t->tm_hour >= (HOURSPERDAY / 2)) ? 285 tptr->pm : 286 tptr->am, 287 pt, ptlim); 288 continue; 289 case 'R': 290 pt = _fmt("%H:%M", t, pt, ptlim, warnp); 291 continue; 292 case 'r': 293 pt = _fmt(tptr->ampm_fmt, t, pt, ptlim, 294 warnp); 295 continue; 296 case 'S': 297 pt = _conv(t->tm_sec, fmt_padding[PAD_FMT_HMS][PadIndex], 298 pt, ptlim); 299 continue; 300 case 's': 301 { 302 struct tm tm; 303 char buf[INT_STRLEN_MAXIMUM( 304 time_t) + 1]; 305 time_t mkt; 306 307 tm = *t; 308 mkt = mktime(&tm); 309 if (TYPE_SIGNED(time_t)) 310 (void) sprintf(buf, "%ld", 311 (long) mkt); 312 else (void) sprintf(buf, "%lu", 313 (unsigned long) mkt); 314 pt = _add(buf, pt, ptlim); 315 } 316 continue; 317 case 'T': 318 pt = _fmt("%H:%M:%S", t, pt, ptlim, warnp); 319 continue; 320 case 't': 321 pt = _add("\t", pt, ptlim); 322 continue; 323 case 'U': 324 pt = _conv((t->tm_yday + DAYSPERWEEK - 325 t->tm_wday) / DAYSPERWEEK, 326 fmt_padding[PAD_FMT_WEEKOFYEAR][PadIndex], pt, ptlim); 327 continue; 328 case 'u': 329 /* 330 ** From Arnold Robbins' strftime version 3.0: 331 ** "ISO 8601: Weekday as a decimal number 332 ** [1 (Monday) - 7]" 333 ** (ado, 1993-05-24) 334 */ 335 pt = _conv((t->tm_wday == 0) ? 336 DAYSPERWEEK : t->tm_wday, 337 "%d", pt, ptlim); 338 continue; 339 case 'V': /* ISO 8601 week number */ 340 case 'G': /* ISO 8601 year (four digits) */ 341 case 'g': /* ISO 8601 year (two digits) */ 342/* 343** From Arnold Robbins' strftime version 3.0: "the week number of the 344** year (the first Monday as the first day of week 1) as a decimal number 345** (01-53)." 346** (ado, 1993-05-24) 347** 348** From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn: 349** "Week 01 of a year is per definition the first week which has the 350** Thursday in this year, which is equivalent to the week which contains 351** the fourth day of January. In other words, the first week of a new year 352** is the week which has the majority of its days in the new year. Week 01 353** might also contain days from the previous year and the week before week 354** 01 of a year is the last week (52 or 53) of the previous year even if 355** it contains days from the new year. A week starts with Monday (day 1) 356** and ends with Sunday (day 7). For example, the first week of the year 357** 1997 lasts from 1996-12-30 to 1997-01-05..." 358** (ado, 1996-01-02) 359*/ 360 { 361 int year; 362 int yday; 363 int wday; 364 int w; 365 366 year = t->tm_year + 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(year) ? 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 ++year; 394 w = 1; 395 break; 396 } 397 if (yday >= bot) { 398 w = 1 + ((yday - bot) / 399 DAYSPERWEEK); 400 break; 401 } 402 --year; 403 yday += isleap(year) ? 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 = _conv(year % 100, fmt_padding[PAD_FMT_SHORTYEAR][PadIndex], 420 pt, ptlim); 421 } else pt = _conv(year, fmt_padding[PAD_FMT_YEAR][PadIndex], 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 = _conv((t->tm_year + TM_YEAR_BASE) % 100, 460 fmt_padding[PAD_FMT_SHORTYEAR][PadIndex], pt, ptlim); 461 continue; 462 case 'Y': 463 pt = _conv(t->tm_year + TM_YEAR_BASE, 464 fmt_padding[PAD_FMT_YEAR][PadIndex], 465 pt, ptlim); 466 continue; 467 case 'Z': 468#ifdef TM_ZONE 469 if (t->TM_ZONE != NULL) 470 pt = _add(t->TM_ZONE, pt, ptlim); 471 else 472#endif /* defined TM_ZONE */ 473 if (t->tm_isdst >= 0) 474 pt = _add(tzname[t->tm_isdst != 0], 475 pt, ptlim); 476 /* 477 ** C99 says that %Z must be replaced by the 478 ** empty string if the time zone is not 479 ** determinable. 480 */ 481 continue; 482 case 'z': 483 { 484 int diff; 485 char const * sign; 486 487 if (t->tm_isdst < 0) 488 continue; 489#ifdef TM_GMTOFF 490 diff = t->TM_GMTOFF; 491#else /* !defined TM_GMTOFF */ 492 /* 493 ** C99 says that the UTC offset must 494 ** be computed by looking only at 495 ** tm_isdst. This requirement is 496 ** incorrect, since it means the code 497 ** must rely on magic (in this case 498 ** altzone and timezone), and the 499 ** magic might not have the correct 500 ** offset. Doing things correctly is 501 ** tricky and requires disobeying C99; 502 ** see GNU C strftime for details. 503 ** For now, punt and conform to the 504 ** standard, even though it's incorrect. 505 ** 506 ** C99 says that %z must be replaced by the 507 ** empty string if the time zone is not 508 ** determinable, so output nothing if the 509 ** appropriate variables are not available. 510 */ 511 if (t->tm_isdst == 0) 512#ifdef USG_COMPAT 513 diff = -timezone; 514#else /* !defined USG_COMPAT */ 515 continue; 516#endif /* !defined USG_COMPAT */ 517 else 518#ifdef ALTZONE 519 diff = -altzone; 520#else /* !defined ALTZONE */ 521 continue; 522#endif /* !defined ALTZONE */ 523#endif /* !defined TM_GMTOFF */ 524 if (diff < 0) { 525 sign = "-"; 526 diff = -diff; 527 } else sign = "+"; 528 pt = _add(sign, pt, ptlim); 529 diff /= 60; 530 pt = _conv((diff/60)*100 + diff%60, 531 fmt_padding[PAD_FMT_YEAR][PadIndex], pt, ptlim); 532 } 533 continue; 534 case '+': 535 pt = _fmt(tptr->date_fmt, t, pt, ptlim, 536 warnp); 537 continue; 538 case '-': 539 if (PadIndex != PAD_DEFAULT) 540 break; 541 PadIndex = PAD_LESS; 542 goto label; 543 case '_': 544 if (PadIndex != PAD_DEFAULT) 545 break; 546 PadIndex = PAD_SPACE; 547 goto label; 548 case '0': 549 if (PadIndex != PAD_DEFAULT) 550 break; 551 PadIndex = PAD_ZERO; 552 goto label; 553 case '%': 554 /* 555 ** X311J/88-090 (4.12.3.5): if conversion char is 556 ** undefined, behavior is undefined. Print out the 557 ** character itself as printf(3) also does. 558 */ 559 default: 560 break; 561 } 562 } 563 if (pt == ptlim) 564 break; 565 *pt++ = *format; 566 } 567 return pt; 568} 569 570static char * 571_conv(n, format, pt, ptlim) 572const int n; 573const char * const format; 574char * const pt; 575const char * const ptlim; 576{ 577 char buf[INT_STRLEN_MAXIMUM(int) + 1]; 578 579 (void) sprintf(buf, format, n); 580 return _add(buf, pt, ptlim); 581} 582 583static char * 584_add(str, pt, ptlim) 585const char * str; 586char * pt; 587const char * const ptlim; 588{ 589 while (pt < ptlim && (*pt = *str++) != '\0') 590 ++pt; 591 return pt; 592} 593