1/* $OpenBSD: strftime.c,v 1.33 2020/07/16 20:08:12 millert Exp $ */ 2/* 3** Copyright (c) 1989, 1993 4** The Regents of the University of California. All rights reserved. 5** 6** Redistribution and use in source and binary forms, with or without 7** modification, are permitted provided that the following conditions 8** are met: 9** 1. Redistributions of source code must retain the above copyright 10** notice, this list of conditions and the following disclaimer. 11** 2. Redistributions in binary form must reproduce the above copyright 12** notice, this list of conditions and the following disclaimer in the 13** documentation and/or other materials provided with the distribution. 14** 3. Neither the name of the University nor the names of its contributors 15** may be used to endorse or promote products derived from this software 16** without specific prior written permission. 17** 18** THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19** ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20** IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21** ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22** FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23** DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24** OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25** HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26** LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27** OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28** SUCH DAMAGE. 29*/ 30 31#include <fcntl.h> 32#include <stdio.h> 33 34#include "private.h" 35#include "tzfile.h" 36 37struct lc_time_T { 38 const char * mon[MONSPERYEAR]; 39 const char * month[MONSPERYEAR]; 40 const char * wday[DAYSPERWEEK]; 41 const char * weekday[DAYSPERWEEK]; 42 const char * X_fmt; 43 const char * x_fmt; 44 const char * c_fmt; 45 const char * am; 46 const char * pm; 47 const char * date_fmt; 48}; 49 50#define Locale (&C_time_locale) 51static const struct lc_time_T C_time_locale = { 52 { 53 "Jan", "Feb", "Mar", "Apr", "May", "Jun", 54 "Jul", "Aug", "Sep", "Oct", "Nov", "Dec" 55 }, { 56 "January", "February", "March", "April", "May", "June", 57 "July", "August", "September", "October", "November", "December" 58 }, { 59 "Sun", "Mon", "Tue", "Wed", 60 "Thu", "Fri", "Sat" 61 }, { 62 "Sunday", "Monday", "Tuesday", "Wednesday", 63 "Thursday", "Friday", "Saturday" 64 }, 65 66 /* X_fmt */ 67 "%H:%M:%S", 68 69 /* 70 ** x_fmt 71 ** C99 requires this format. 72 ** Using just numbers (as here) makes Quakers happier; 73 ** it's also compatible with SVR4. 74 */ 75 "%m/%d/%y", 76 77 /* 78 ** c_fmt 79 ** C99 requires this format. 80 ** Previously this code used "%D %X", but we now conform to C99. 81 ** Note that 82 ** "%a %b %d %H:%M:%S %Y" 83 ** is used by Solaris 2.3. 84 */ 85 "%a %b %e %T %Y", 86 87 /* am */ 88 "AM", 89 90 /* pm */ 91 "PM", 92 93 /* date_fmt */ 94 "%a %b %e %H:%M:%S %Z %Y" 95}; 96 97static char * _add(const char *, char *, const char *); 98static char * _conv(int, const char *, char *, const char *); 99static char * _fmt(const char *, const struct tm *, char *, const char *, 100 int *); 101static char * _yconv(int, int, int, int, char *, const char *); 102 103extern char * tzname[]; 104 105#define IN_NONE 0 106#define IN_SOME 1 107#define IN_THIS 2 108#define IN_ALL 3 109 110size_t 111strftime(char *s, size_t maxsize, const char *format, const struct tm *t) 112{ 113 char * p; 114 int warn; 115 116 tzset(); 117 warn = IN_NONE; 118 p = _fmt(((format == NULL) ? "%c" : format), t, s, s + maxsize, &warn); 119 if (p == s + maxsize) { 120 if (maxsize > 0) 121 s[maxsize - 1] = '\0'; 122 return 0; 123 } 124 *p = '\0'; 125 return p - s; 126} 127DEF_STRONG(strftime); 128 129static char * 130_fmt(const char *format, const struct tm *t, char *pt, const char *ptlim, int *warnp) 131{ 132 for ( ; *format; ++format) { 133 if (*format == '%') { 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 "?" : Locale->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 "?" : Locale->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 "?" : Locale->month[t->tm_mon], 155 pt, ptlim); 156 continue; 157 case 'b': 158 case 'h': 159 pt = _add((t->tm_mon < 0 || 160 t->tm_mon >= MONSPERYEAR) ? 161 "?" : Locale->mon[t->tm_mon], 162 pt, ptlim); 163 continue; 164 case 'C': 165 /* 166 ** %C used to do a... 167 ** _fmt("%a %b %e %X %Y", t); 168 ** ...whereas now POSIX 1003.2 calls for 169 ** something completely different. 170 ** (ado, 1993-05-24) 171 */ 172 pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 0, 173 pt, ptlim); 174 continue; 175 case 'c': 176 { 177 int warn2 = IN_SOME; 178 179 pt = _fmt(Locale->c_fmt, t, pt, ptlim, &warn2); 180 if (warn2 == IN_ALL) 181 warn2 = IN_THIS; 182 if (warn2 > *warnp) 183 *warnp = warn2; 184 } 185 continue; 186 case 'D': 187 pt = _fmt("%m/%d/%y", t, pt, ptlim, warnp); 188 continue; 189 case 'd': 190 pt = _conv(t->tm_mday, "%02d", pt, ptlim); 191 continue; 192 case 'E': 193 case 'O': 194 /* 195 ** C99 locale modifiers. 196 ** The sequences 197 ** %Ec %EC %Ex %EX %Ey %EY 198 ** %Od %oe %OH %OI %Om %OM 199 ** %OS %Ou %OU %OV %Ow %OW %Oy 200 ** are supposed to provide alternate 201 ** representations. 202 */ 203 goto label; 204 case 'e': 205 pt = _conv(t->tm_mday, "%2d", pt, ptlim); 206 continue; 207 case 'F': 208 pt = _fmt("%Y-%m-%d", t, pt, ptlim, warnp); 209 continue; 210 case 'H': 211 pt = _conv(t->tm_hour, "%02d", pt, ptlim); 212 continue; 213 case 'I': 214 pt = _conv((t->tm_hour % 12) ? 215 (t->tm_hour % 12) : 12, 216 "%02d", pt, ptlim); 217 continue; 218 case 'j': 219 pt = _conv(t->tm_yday + 1, "%03d", pt, ptlim); 220 continue; 221 case 'k': 222 /* 223 ** This used to be... 224 ** _conv(t->tm_hour % 12 ? 225 ** t->tm_hour % 12 : 12, 2, ' '); 226 ** ...and has been changed to the below to 227 ** match SunOS 4.1.1 and Arnold Robbins' 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, "%2d", pt, ptlim); 233 continue; 234#ifdef KITCHEN_SINK 235 case 'K': 236 /* 237 ** After all this time, still unclaimed! 238 */ 239 pt = _add("kitchen sink", pt, ptlim); 240 continue; 241#endif /* defined KITCHEN_SINK */ 242 case 'l': 243 /* 244 ** This used to be... 245 ** _conv(t->tm_hour, 2, ' '); 246 ** ...and has been changed to the below to 247 ** match SunOS 4.1.1 and Arnold Robbin's 248 ** strftime version 3.0. That is, "%k" and 249 ** "%l" have been swapped. 250 ** (ado, 1993-05-24) 251 */ 252 pt = _conv((t->tm_hour % 12) ? 253 (t->tm_hour % 12) : 12, 254 "%2d", pt, ptlim); 255 continue; 256 case 'M': 257 pt = _conv(t->tm_min, "%02d", pt, ptlim); 258 continue; 259 case 'm': 260 pt = _conv(t->tm_mon + 1, "%02d", pt, ptlim); 261 continue; 262 case 'n': 263 pt = _add("\n", pt, ptlim); 264 continue; 265 case 'p': 266 pt = _add((t->tm_hour >= (HOURSPERDAY / 2)) ? 267 Locale->pm : 268 Locale->am, 269 pt, ptlim); 270 continue; 271 case 'R': 272 pt = _fmt("%H:%M", t, pt, ptlim, warnp); 273 continue; 274 case 'r': 275 pt = _fmt("%I:%M:%S %p", t, pt, ptlim, warnp); 276 continue; 277 case 'S': 278 pt = _conv(t->tm_sec, "%02d", pt, ptlim); 279 continue; 280 case 's': 281 { 282 struct tm tm; 283 char buf[INT_STRLEN_MAXIMUM( 284 time_t) + 1]; 285 time_t mkt; 286 287 tm = *t; 288 mkt = mktime(&tm); 289 (void) snprintf(buf, sizeof buf, 290 "%ld", (long) mkt); 291 pt = _add(buf, pt, ptlim); 292 } 293 continue; 294 case 'T': 295 pt = _fmt("%H:%M:%S", t, pt, ptlim, warnp); 296 continue; 297 case 't': 298 pt = _add("\t", pt, ptlim); 299 continue; 300 case 'U': 301 pt = _conv((t->tm_yday + DAYSPERWEEK - 302 t->tm_wday) / DAYSPERWEEK, 303 "%02d", pt, ptlim); 304 continue; 305 case 'u': 306 /* 307 ** From Arnold Robbins' strftime version 3.0: 308 ** "ISO 8601: Weekday as a decimal number 309 ** [1 (Monday) - 7]" 310 ** (ado, 1993-05-24) 311 */ 312 pt = _conv((t->tm_wday == 0) ? 313 DAYSPERWEEK : t->tm_wday, 314 "%d", pt, ptlim); 315 continue; 316 case 'V': /* ISO 8601 week number */ 317 case 'G': /* ISO 8601 year (four digits) */ 318 case 'g': /* ISO 8601 year (two digits) */ 319/* 320** From Arnold Robbins' strftime version 3.0: "the week number of the 321** year (the first Monday as the first day of week 1) as a decimal number 322** (01-53)." 323** (ado, 1993-05-24) 324** 325** From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn: 326** "Week 01 of a year is per definition the first week which has the 327** Thursday in this year, which is equivalent to the week which contains 328** the fourth day of January. In other words, the first week of a new year 329** is the week which has the majority of its days in the new year. Week 01 330** might also contain days from the previous year and the week before week 331** 01 of a year is the last week (52 or 53) of the previous year even if 332** it contains days from the new year. A week starts with Monday (day 1) 333** and ends with Sunday (day 7). For example, the first week of the year 334** 1997 lasts from 1996-12-30 to 1997-01-05..." 335** (ado, 1996-01-02) 336*/ 337 { 338 int year; 339 int base; 340 int yday; 341 int wday; 342 int w; 343 344 year = t->tm_year; 345 base = TM_YEAR_BASE; 346 yday = t->tm_yday; 347 wday = t->tm_wday; 348 for ( ; ; ) { 349 int len; 350 int bot; 351 int top; 352 353 len = isleap_sum(year, base) ? 354 DAYSPERLYEAR : 355 DAYSPERNYEAR; 356 /* 357 ** What yday (-3 ... 3) does 358 ** the ISO year begin on? 359 */ 360 bot = ((yday + 11 - wday) % 361 DAYSPERWEEK) - 3; 362 /* 363 ** What yday does the NEXT 364 ** ISO year begin on? 365 */ 366 top = bot - 367 (len % DAYSPERWEEK); 368 if (top < -3) 369 top += DAYSPERWEEK; 370 top += len; 371 if (yday >= top) { 372 ++base; 373 w = 1; 374 break; 375 } 376 if (yday >= bot) { 377 w = 1 + ((yday - bot) / 378 DAYSPERWEEK); 379 break; 380 } 381 --base; 382 yday += isleap_sum(year, base) ? 383 DAYSPERLYEAR : 384 DAYSPERNYEAR; 385 } 386#ifdef XPG4_1994_04_09 387 if ((w == 52 && 388 t->tm_mon == TM_JANUARY) || 389 (w == 1 && 390 t->tm_mon == TM_DECEMBER)) 391 w = 53; 392#endif /* defined XPG4_1994_04_09 */ 393 if (*format == 'V') 394 pt = _conv(w, "%02d", 395 pt, ptlim); 396 else if (*format == 'g') { 397 *warnp = IN_ALL; 398 pt = _yconv(year, base, 0, 1, 399 pt, ptlim); 400 } else pt = _yconv(year, base, 1, 1, 401 pt, ptlim); 402 } 403 continue; 404 case 'v': 405 /* 406 ** From Arnold Robbins' strftime version 3.0: 407 ** "date as dd-bbb-YYYY" 408 ** (ado, 1993-05-24) 409 */ 410 pt = _fmt("%e-%b-%Y", t, pt, ptlim, warnp); 411 continue; 412 case 'W': 413 pt = _conv((t->tm_yday + DAYSPERWEEK - 414 (t->tm_wday ? 415 (t->tm_wday - 1) : 416 (DAYSPERWEEK - 1))) / DAYSPERWEEK, 417 "%02d", pt, ptlim); 418 continue; 419 case 'w': 420 pt = _conv(t->tm_wday, "%d", pt, ptlim); 421 continue; 422 case 'X': 423 pt = _fmt(Locale->X_fmt, t, pt, ptlim, warnp); 424 continue; 425 case 'x': 426 { 427 int warn2 = IN_SOME; 428 429 pt = _fmt(Locale->x_fmt, t, pt, ptlim, &warn2); 430 if (warn2 == IN_ALL) 431 warn2 = IN_THIS; 432 if (warn2 > *warnp) 433 *warnp = warn2; 434 } 435 continue; 436 case 'y': 437 *warnp = IN_ALL; 438 pt = _yconv(t->tm_year, TM_YEAR_BASE, 0, 1, 439 pt, ptlim); 440 continue; 441 case 'Y': 442 pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 1, 443 pt, ptlim); 444 continue; 445 case 'Z': 446 if (t->tm_zone != NULL) 447 pt = _add(t->tm_zone, pt, ptlim); 448 else if (t->tm_isdst >= 0) 449 pt = _add(tzname[t->tm_isdst != 0], 450 pt, ptlim); 451 /* 452 ** C99 says that %Z must be replaced by the 453 ** empty string if the time zone is not 454 ** determinable. 455 */ 456 continue; 457 case 'z': 458 { 459 int diff; 460 char const * sign; 461 462 if (t->tm_isdst < 0) 463 continue; 464 diff = t->tm_gmtoff; 465 if (diff < 0) { 466 sign = "-"; 467 diff = -diff; 468 } else sign = "+"; 469 pt = _add(sign, pt, ptlim); 470 diff /= SECSPERMIN; 471 diff = (diff / MINSPERHOUR) * 100 + 472 (diff % MINSPERHOUR); 473 pt = _conv(diff, "%04d", pt, ptlim); 474 } 475 continue; 476 case '+': 477 pt = _fmt(Locale->date_fmt, t, pt, ptlim, 478 warnp); 479 continue; 480 case '%': 481 /* 482 ** X311J/88-090 (4.12.3.5): if conversion char is 483 ** undefined, behavior is undefined. Print out the 484 ** character itself as printf(3) also does. 485 */ 486 default: 487 break; 488 } 489 } 490 if (pt == ptlim) 491 break; 492 *pt++ = *format; 493 } 494 return pt; 495} 496 497static char * 498_conv(int n, const char *format, char *pt, const char *ptlim) 499{ 500 char buf[INT_STRLEN_MAXIMUM(int) + 1]; 501 502 (void) snprintf(buf, sizeof buf, format, n); 503 return _add(buf, pt, ptlim); 504} 505 506static char * 507_add(const char *str, char *pt, const char *ptlim) 508{ 509 while (pt < ptlim && (*pt = *str++) != '\0') 510 ++pt; 511 return pt; 512} 513 514/* 515** POSIX and the C Standard are unclear or inconsistent about 516** what %C and %y do if the year is negative or exceeds 9999. 517** Use the convention that %C concatenated with %y yields the 518** same output as %Y, and that %Y contains at least 4 bytes, 519** with more only if necessary. 520*/ 521 522static char * 523_yconv(int a, int b, int convert_top, int convert_yy, char *pt, const char *ptlim) 524{ 525 int lead; 526 int trail; 527 528#define DIVISOR 100 529 trail = a % DIVISOR + b % DIVISOR; 530 lead = a / DIVISOR + b / DIVISOR + trail / DIVISOR; 531 trail %= DIVISOR; 532 if (trail < 0 && lead > 0) { 533 trail += DIVISOR; 534 --lead; 535 } else if (lead < 0 && trail > 0) { 536 trail -= DIVISOR; 537 ++lead; 538 } 539 if (convert_top) { 540 if (lead == 0 && trail < 0) 541 pt = _add("-0", pt, ptlim); 542 else pt = _conv(lead, "%02d", pt, ptlim); 543 } 544 if (convert_yy) 545 pt = _conv(((trail < 0) ? -trail : trail), "%02d", pt, ptlim); 546 return pt; 547} 548