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 fprintf_l(stderr, loc, "\n"); 91 if (format == NULL) 92 fprintf_l(stderr, loc, "NULL strftime format "); 93 else fprintf_l(stderr, loc, "strftime format \"%s\" ", 94 format); 95 fprintf_l(stderr, loc, "yields only two digits of years in "); 96 if (warn == IN_SOME) 97 fprintf_l(stderr, loc, "some locales"); 98 else if (warn == IN_THIS) 99 fprintf_l(stderr, loc, "the current locale"); 100 else fprintf_l(stderr, loc, "all locales"); 101 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 snprintf(buf, sizeof(buf), 306 "%"PRIdMAX, 307 (intmax_t) mkt); 308 else snprintf(buf, sizeof(buf), 309 "%"PRIuMAX, 310 (uintmax_t) mkt); 311 pt = _add(buf, pt, ptlim); 312 } 313 continue; 314 case 'T': 315 pt = _fmt("%H:%M:%S", t, pt, ptlim, warnp, loc); 316 continue; 317 case 't': 318 pt = _add("\t", pt, ptlim); 319 continue; 320 case 'U': 321 pt = _conv((t->tm_yday + DAYSPERWEEK - 322 t->tm_wday) / DAYSPERWEEK, 323 fmt_padding[PAD_FMT_WEEKOFYEAR][PadIndex], pt, ptlim); 324 continue; 325 case 'u': 326 /* 327 * From Arnold Robbins' strftime version 3.0: 328 * "ISO 8601: Weekday as a decimal number 329 * [1 (Monday) - 7]" 330 * (ado, 1993-05-24) 331 */ 332 pt = _conv((t->tm_wday == 0) ? 333 DAYSPERWEEK : t->tm_wday, 334 "%d", pt, ptlim); 335 continue; 336 case 'V': /* ISO 8601 week number */ 337 case 'G': /* ISO 8601 year (four digits) */ 338 case 'g': /* ISO 8601 year (two digits) */ 339 /* 340 * From Arnold Robbins' strftime version 3.0: "the week number of the 341 * year (the first Monday as the first day of week 1) as a decimal number 342 * (01-53)." 343 * (ado, 1993-05-24) 344 * 345 * From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn: 346 * "Week 01 of a year is per definition the first week which has the 347 * Thursday in this year, which is equivalent to the week which contains 348 * the fourth day of January. In other words, the first week of a new year 349 * is the week which has the majority of its days in the new year. Week 01 350 * might also contain days from the previous year and the week before week 351 * 01 of a year is the last week (52 or 53) of the previous year even if 352 * it contains days from the new year. A week starts with Monday (day 1) 353 * and ends with Sunday (day 7). For example, the first week of the year 354 * 1997 lasts from 1996-12-30 to 1997-01-05..." 355 * (ado, 1996-01-02) 356 */ 357 { 358 int year; 359 int base; 360 int yday; 361 int wday; 362 int w; 363 364 year = t->tm_year; 365 base = TM_YEAR_BASE; 366 yday = t->tm_yday; 367 wday = t->tm_wday; 368 for ( ; ; ) { 369 int len; 370 int bot; 371 int top; 372 373 len = isleap_sum(year, base) ? 374 DAYSPERLYEAR : 375 DAYSPERNYEAR; 376 /* 377 * What yday (-3 ... 3) does 378 * the ISO year begin on? 379 */ 380 bot = ((yday + 11 - wday) % 381 DAYSPERWEEK) - 3; 382 /* 383 * What yday does the NEXT 384 * ISO year begin on? 385 */ 386 top = bot - 387 (len % DAYSPERWEEK); 388 if (top < -3) 389 top += DAYSPERWEEK; 390 top += len; 391 if (yday >= top) { 392 ++base; 393 w = 1; 394 break; 395 } 396 if (yday >= bot) { 397 w = 1 + ((yday - bot) / 398 DAYSPERWEEK); 399 break; 400 } 401 --base; 402 yday += isleap_sum(year, base) ? 403 DAYSPERLYEAR : 404 DAYSPERNYEAR; 405 } 406 #ifdef XPG4_1994_04_09 407 if ((w == 52 && 408 t->tm_mon == TM_JANUARY) || 409 (w == 1 && 410 t->tm_mon == TM_DECEMBER)) 411 w = 53; 412 #endif /* defined XPG4_1994_04_09 */ 413 if (*format == 'V') 414 pt = _conv(w, fmt_padding[PAD_FMT_WEEKOFYEAR][PadIndex], 415 pt, ptlim); 416 else if (*format == 'g') { 417 *warnp = IN_ALL; 418 pt = _yconv(year, base, 0, 1, 419 pt, ptlim); 420 } else pt = _yconv(year, base, 1, 1, 421 pt, ptlim); 422 } 423 continue; 424 case 'v': 425 /* 426 * From Arnold Robbins' strftime version 3.0: 427 * "date as dd-bbb-YYYY" 428 * (ado, 1993-05-24) 429 */ 430 pt = _fmt("%e-%b-%Y", t, pt, ptlim, warnp, loc); 431 continue; 432 case 'W': 433 pt = _conv((t->tm_yday + DAYSPERWEEK - 434 (t->tm_wday ? 435 (t->tm_wday - 1) : 436 (DAYSPERWEEK - 1))) / DAYSPERWEEK, 437 fmt_padding[PAD_FMT_WEEKOFYEAR][PadIndex], pt, ptlim); 438 continue; 439 case 'w': 440 pt = _conv(t->tm_wday, "%d", pt, ptlim); 441 continue; 442 case 'X': 443 pt = _fmt(tptr->X_fmt, t, pt, ptlim, warnp, loc); 444 continue; 445 case 'x': 446 { 447 int warn2 = IN_SOME; 448 449 pt = _fmt(tptr->x_fmt, t, pt, ptlim, &warn2, loc); 450 if (warn2 == IN_ALL) 451 warn2 = IN_THIS; 452 if (warn2 > *warnp) 453 *warnp = warn2; 454 } 455 continue; 456 case 'y': 457 *warnp = IN_ALL; 458 pt = _yconv(t->tm_year, TM_YEAR_BASE, 0, 1, 459 pt, ptlim); 460 continue; 461 case 'Y': 462 pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 1, 463 pt, ptlim); 464 continue; 465 case 'Z': 466 #ifdef TM_ZONE 467 if (t->TM_ZONE != NULL) 468 pt = _add(t->TM_ZONE, pt, ptlim); 469 else 470 #endif /* defined TM_ZONE */ 471 if (t->tm_isdst >= 0) 472 pt = _add(tzname[t->tm_isdst != 0], 473 pt, ptlim); 474 /* 475 * C99 says that %Z must be replaced by the 476 * empty string if the time zone is not 477 * determinable. 478 */ 479 continue; 480 case 'z': 481 { 482 long diff; 483 char const * sign; 484 485 if (t->tm_isdst < 0) 486 continue; 487 #ifdef TM_GMTOFF 488 diff = t->TM_GMTOFF; 489 #else /* !defined TM_GMTOFF */ 490 /* 491 * C99 says that the UTC offset must 492 * be computed by looking only at 493 * tm_isdst. This requirement is 494 * incorrect, since it means the code 495 * must rely on magic (in this case 496 * altzone and timezone), and the 497 * magic might not have the correct 498 * offset. Doing things correctly is 499 * tricky and requires disobeying C99; 500 * see GNU C strftime for details. 501 * For now, punt and conform to the 502 * standard, even though it's incorrect. 503 * 504 * C99 says that %z must be replaced by the 505 * empty string if the time zone is not 506 * determinable, so output nothing if the 507 * appropriate variables are not available. 508 */ 509 if (t->tm_isdst == 0) 510 diff = -timezone; 511 else 512 continue; 513 #endif /* !defined TM_GMTOFF */ 514 if (diff < 0) { 515 sign = "-"; 516 diff = -diff; 517 } else 518 sign = "+"; 519 pt = _add(sign, pt, ptlim); 520 diff /= SECSPERMIN; 521 diff = (diff / MINSPERHOUR) * 100 + 522 (diff % MINSPERHOUR); 523 pt = _conv(diff, 524 fmt_padding[PAD_FMT_YEAR][PadIndex], pt, ptlim); 525 } 526 continue; 527 case '+': 528 pt = _fmt(tptr->date_fmt, t, pt, ptlim, 529 warnp, loc); 530 continue; 531 case '-': 532 if (PadIndex != PAD_DEFAULT) 533 break; 534 PadIndex = PAD_LESS; 535 goto label; 536 case '_': 537 if (PadIndex != PAD_DEFAULT) 538 break; 539 PadIndex = PAD_SPACE; 540 goto label; 541 case '0': 542 if (PadIndex != PAD_DEFAULT) 543 break; 544 PadIndex = PAD_ZERO; 545 goto label; 546 case '%': 547 /* 548 * X311J/88-090 (4.12.3.5): if conversion char is 549 * undefined, behavior is undefined. Print out the 550 * character itself as printf(3) also does. 551 */ 552 default: 553 break; 554 } 555 } 556 if (pt == ptlim) 557 break; 558 *pt++ = *format; 559 } 560 return pt; 561 } 562 563 static char * 564 _conv(const int n, const char * const format, char * const pt, 565 const char * const ptlim) 566 { 567 char buf[INT_STRLEN_MAXIMUM(int) + 1]; 568 569 snprintf(buf, sizeof(buf), format, n); 570 return _add(buf, pt, ptlim); 571 } 572 573 static char * 574 _add(const char *str, char *pt, const char * const ptlim) 575 { 576 while (pt < ptlim && (*pt = *str++) != '\0') 577 ++pt; 578 return pt; 579 } 580 581 /* 582 * POSIX and the C Standard are unclear or inconsistent about 583 * what %C and %y do if the year is negative or exceeds 9999. 584 * Use the convention that %C concatenated with %y yields the 585 * same output as %Y, and that %Y contains at least 4 bytes, 586 * with more only if necessary. 587 */ 588 589 static char * 590 _yconv(const int a, const int b, const int convert_top, const int convert_yy, 591 char *pt, const char * const ptlim) 592 { 593 int lead; 594 int trail; 595 596 #define DIVISOR 100 597 trail = a % DIVISOR + b % DIVISOR; 598 lead = a / DIVISOR + b / DIVISOR + trail / DIVISOR; 599 trail %= DIVISOR; 600 if (trail < 0 && lead > 0) { 601 trail += DIVISOR; 602 --lead; 603 } else if (lead < 0 && trail > 0) { 604 trail -= DIVISOR; 605 ++lead; 606 } 607 if (convert_top) { 608 if (lead == 0 && trail < 0) 609 pt = _add("-0", pt, ptlim); 610 else pt = _conv(lead, "%02d", pt, ptlim); 611 } 612 if (convert_yy) 613 pt = _conv(((trail < 0) ? -trail : trail), "%02d", pt, ptlim); 614 return pt; 615 } 616