strftime.c revision 74578
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#ifdef LIBC_RCS 19static const char rcsid[] = 20 "$FreeBSD: head/lib/libc/stdtime/strftime.c 74578 2001-03-21 14:52:12Z ache $"; 21#endif 22 23#ifndef lint 24#ifndef NOID 25static const char elsieid[] = "@(#)strftime.c 7.38"; 26/* 27** Based on the UCB version with the ID appearing below. 28** This is ANSIish only when "multibyte character == plain character". 29*/ 30#endif /* !defined NOID */ 31#endif /* !defined lint */ 32 33#include "namespace.h" 34#include "private.h" 35 36#ifndef LIBC_SCCS 37#ifndef lint 38static const char sccsid[] = "@(#)strftime.c 5.4 (Berkeley) 3/14/89"; 39#endif /* !defined lint */ 40#endif /* !defined LIBC_SCCS */ 41 42#include "tzfile.h" 43#include <fcntl.h> 44#include <sys/stat.h> 45#include "un-namespace.h" 46#include "timelocal.h" 47 48static char * _add P((const char *, char *, const char *)); 49static char * _conv P((int, const char *, char *, const char *)); 50static char * _fmt P((const char *, const struct tm *, char *, const char *)); 51 52size_t strftime P((char *, size_t, const char *, const struct tm *)); 53 54extern char * tzname[]; 55 56size_t 57strftime(s, maxsize, format, t) 58 char *const s; 59 const size_t maxsize; 60 const char *const format; 61 const struct tm *const t; 62{ 63 char *p; 64 65 tzset(); 66 p = _fmt(((format == NULL) ? "%c" : format), t, s, s + maxsize); 67 if (p == s + maxsize) 68 return 0; 69 *p = '\0'; 70 return p - s; 71} 72 73static char * 74_fmt(format, t, pt, ptlim) 75 const char *format; 76 const struct tm *const t; 77 char *pt; 78 const char *const ptlim; 79{ 80 int Ealternative, Oalternative; 81 struct lc_time_T *tptr = __get_current_time_locale(); 82 83 for ( ; *format; ++format) { 84 if (*format == '%') { 85 Ealternative = 0; 86 Oalternative = 0; 87label: 88 switch (*++format) { 89 case '\0': 90 --format; 91 break; 92 case 'A': 93 pt = _add((t->tm_wday < 0 || t->tm_wday > 6) ? 94 "?" : tptr->weekday[t->tm_wday], 95 pt, ptlim); 96 continue; 97 case 'a': 98 pt = _add((t->tm_wday < 0 || t->tm_wday > 6) ? 99 "?" : tptr->wday[t->tm_wday], 100 pt, ptlim); 101 continue; 102 case 'B': 103 pt = _add((t->tm_mon < 0 || t->tm_mon > 11) ? 104 "?" : (Oalternative ? tptr->alt_month : 105 tptr->month)[t->tm_mon], 106 pt, ptlim); 107 continue; 108 case 'b': 109 case 'h': 110 pt = _add((t->tm_mon < 0 || t->tm_mon > 11) ? 111 "?" : tptr->mon[t->tm_mon], 112 pt, ptlim); 113 continue; 114 case 'C': 115 /* 116 ** %C used to do a... 117 ** _fmt("%a %b %e %X %Y", t); 118 ** ...whereas now POSIX 1003.2 calls for 119 ** something completely different. 120 ** (ado, 5/24/93) 121 */ 122 pt = _conv((t->tm_year + TM_YEAR_BASE) / 100, 123 "%02d", pt, ptlim); 124 continue; 125 case 'c': 126 pt = _fmt(tptr->c_fmt, t, pt, ptlim); 127 continue; 128 case 'D': 129 pt = _fmt("%m/%d/%y", t, pt, ptlim); 130 continue; 131 case 'd': 132 pt = _conv(t->tm_mday, "%02d", pt, ptlim); 133 continue; 134 case 'E': 135 if (Ealternative || Oalternative) 136 break; 137 Ealternative++; 138 goto label; 139 case 'O': 140 /* 141 ** POSIX locale extensions, a la 142 ** Arnold Robbins' strftime version 3.0. 143 ** The sequences 144 ** %Ec %EC %Ex %EX %Ey %EY 145 ** %Od %oe %OH %OI %Om %OM 146 ** %OS %Ou %OU %OV %Ow %OW %Oy 147 ** are supposed to provide alternate 148 ** representations. 149 ** (ado, 5/24/93) 150 ** 151 ** FreeBSD extensions 152 ** %OB %Ef %EF 153 */ 154 if (Ealternative || Oalternative) 155 break; 156 Oalternative++; 157 goto label; 158 case 'e': 159 pt = _conv(t->tm_mday, "%2d", pt, ptlim); 160 continue; 161 case 'F': 162 pt = _fmt("%Y-%m-%d", t, pt, ptlim); 163 continue; 164 case 'H': 165 pt = _conv(t->tm_hour, "%02d", pt, ptlim); 166 continue; 167 case 'I': 168 pt = _conv((t->tm_hour % 12) ? 169 (t->tm_hour % 12) : 12, 170 "%02d", pt, ptlim); 171 continue; 172 case 'j': 173 pt = _conv(t->tm_yday + 1, "%03d", pt, ptlim); 174 continue; 175 case 'k': 176 /* 177 ** This used to be... 178 ** _conv(t->tm_hour % 12 ? 179 ** t->tm_hour % 12 : 12, 2, ' '); 180 ** ...and has been changed to the below to 181 ** match SunOS 4.1.1 and Arnold Robbins' 182 ** strftime version 3.0. That is, "%k" and 183 ** "%l" have been swapped. 184 ** (ado, 5/24/93) 185 */ 186 pt = _conv(t->tm_hour, "%2d", pt, ptlim); 187 continue; 188#ifdef KITCHEN_SINK 189 case 'K': 190 /* 191 ** After all this time, still unclaimed! 192 */ 193 pt = _add("kitchen sink", pt, ptlim); 194 continue; 195#endif /* defined KITCHEN_SINK */ 196 case 'l': 197 /* 198 ** This used to be... 199 ** _conv(t->tm_hour, 2, ' '); 200 ** ...and has been changed to the below to 201 ** match SunOS 4.1.1 and Arnold Robbin's 202 ** strftime version 3.0. That is, "%k" and 203 ** "%l" have been swapped. 204 ** (ado, 5/24/93) 205 */ 206 pt = _conv((t->tm_hour % 12) ? 207 (t->tm_hour % 12) : 12, 208 "%2d", pt, ptlim); 209 continue; 210 case 'M': 211 pt = _conv(t->tm_min, "%02d", pt, ptlim); 212 continue; 213 case 'm': 214 pt = _conv(t->tm_mon + 1, "%02d", pt, ptlim); 215 continue; 216 case 'n': 217 pt = _add("\n", pt, ptlim); 218 continue; 219 case 'p': 220 pt = _add((t->tm_hour >= 12) ? 221 tptr->pm : 222 tptr->am, 223 pt, ptlim); 224 continue; 225 case 'R': 226 pt = _fmt("%H:%M", t, pt, ptlim); 227 continue; 228 case 'r': 229 pt = _fmt(tptr->ampm_fmt, t, pt, ptlim); 230 continue; 231 case 'S': 232 pt = _conv(t->tm_sec, "%02d", pt, ptlim); 233 continue; 234 case 's': 235 { 236 struct tm tm; 237 char buf[INT_STRLEN_MAXIMUM( 238 time_t) + 1]; 239 time_t mkt; 240 241 tm = *t; 242 mkt = mktime(&tm); 243 if (TYPE_SIGNED(time_t)) 244 (void) sprintf(buf, "%ld", 245 (long) mkt); 246 else (void) sprintf(buf, "%lu", 247 (unsigned long) mkt); 248 pt = _add(buf, pt, ptlim); 249 } 250 continue; 251 case 'T': 252 pt = _fmt("%H:%M:%S", t, pt, ptlim); 253 continue; 254 case 't': 255 pt = _add("\t", pt, ptlim); 256 continue; 257 case 'U': 258 pt = _conv((t->tm_yday + 7 - t->tm_wday) / 7, 259 "%02d", pt, ptlim); 260 continue; 261 case 'u': 262 /* 263 ** From Arnold Robbins' strftime version 3.0: 264 ** "ISO 8601: Weekday as a decimal number 265 ** [1 (Monday) - 7]" 266 ** (ado, 5/24/93) 267 */ 268 pt = _conv((t->tm_wday == 0) ? 7 : t->tm_wday, 269 "%d", pt, ptlim); 270 continue; 271 case 'V': /* ISO 8601 week number */ 272 case 'G': /* ISO 8601 year (four digits) */ 273 case 'g': /* ISO 8601 year (two digits) */ 274/* 275** From Arnold Robbins' strftime version 3.0: "the week number of the 276** year (the first Monday as the first day of week 1) as a decimal number 277** (01-53)." 278** (ado, 1993-05-24) 279** 280** From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn: 281** "Week 01 of a year is per definition the first week which has the 282** Thursday in this year, which is equivalent to the week which contains 283** the fourth day of January. In other words, the first week of a new year 284** is the week which has the majority of its days in the new year. Week 01 285** might also contain days from the previous year and the week before week 286** 01 of a year is the last week (52 or 53) of the previous year even if 287** it contains days from the new year. A week starts with Monday (day 1) 288** and ends with Sunday (day 7). For example, the first week of the year 289** 1997 lasts from 1996-12-30 to 1997-01-05..." 290** (ado, 1996-01-02) 291*/ 292 { 293 int year; 294 int yday; 295 int wday; 296 int w; 297 298 year = t->tm_year + TM_YEAR_BASE; 299 yday = t->tm_yday; 300 wday = t->tm_wday; 301 for ( ; ; ) { 302 int len; 303 int bot; 304 int top; 305 306 len = isleap(year) ? 307 DAYSPERLYEAR : 308 DAYSPERNYEAR; 309 /* 310 ** What yday (-3 ... 3) does 311 ** the ISO year begin on? 312 */ 313 bot = ((yday + 11 - wday) % 314 DAYSPERWEEK) - 3; 315 /* 316 ** What yday does the NEXT 317 ** ISO year begin on? 318 */ 319 top = bot - 320 (len % DAYSPERWEEK); 321 if (top < -3) 322 top += DAYSPERWEEK; 323 top += len; 324 if (yday >= top) { 325 ++year; 326 w = 1; 327 break; 328 } 329 if (yday >= bot) { 330 w = 1 + ((yday - bot) / 331 DAYSPERWEEK); 332 break; 333 } 334 --year; 335 yday += isleap(year) ? 336 DAYSPERLYEAR : 337 DAYSPERNYEAR; 338 } 339#ifdef XPG4_1994_04_09 340 if ((w == 52 341 && t->tm_mon == TM_JANUARY) 342 || (w == 1 343 && t->tm_mon == TM_DECEMBER)) 344 w = 53; 345#endif /* defined XPG4_1994_04_09 */ 346 if (*format == 'V') 347 pt = _conv(w, "%02d", 348 pt, ptlim); 349 else if (*format == 'g') { 350 pt = _conv(year % 100, "%02d", 351 pt, ptlim); 352 } else pt = _conv(year, "%04d", 353 pt, ptlim); 354 } 355 continue; 356 case 'v': 357 /* 358 ** From Arnold Robbins' strftime version 3.0: 359 ** "date as dd-bbb-YYYY" 360 ** (ado, 5/24/93) 361 */ 362 pt = _fmt("%e-%b-%Y", t, pt, ptlim); 363 continue; 364 case 'W': 365 pt = _conv((t->tm_yday + 7 - 366 (t->tm_wday ? 367 (t->tm_wday - 1) : 6)) / 7, 368 "%02d", pt, ptlim); 369 continue; 370 case 'w': 371 pt = _conv(t->tm_wday, "%d", pt, ptlim); 372 continue; 373 case 'X': 374 pt = _fmt(tptr->X_fmt, t, pt, ptlim); 375 continue; 376 case 'x': 377 pt = _fmt(tptr->x_fmt, t, pt, ptlim); 378 continue; 379 case 'y': 380 pt = _conv((t->tm_year + TM_YEAR_BASE) % 100, 381 "%02d", pt, ptlim); 382 continue; 383 case 'Y': 384 pt = _conv(t->tm_year + TM_YEAR_BASE, "%04d", 385 pt, ptlim); 386 continue; 387 case 'Z': 388 if (t->tm_zone != NULL) 389 pt = _add(t->tm_zone, pt, ptlim); 390 else 391 if (t->tm_isdst == 0 || t->tm_isdst == 1) { 392 pt = _add(tzname[t->tm_isdst], 393 pt, ptlim); 394 } else pt = _add("?", pt, ptlim); 395 continue; 396 case 'z': 397 { 398 long absoff; 399 if (t->tm_gmtoff >= 0) { 400 absoff = t->tm_gmtoff; 401 pt = _add("+", pt, ptlim); 402 } else { 403 absoff = -t->tm_gmtoff; 404 pt = _add("-", pt, ptlim); 405 } 406 pt = _conv(absoff / 3600, "%02d", 407 pt, ptlim); 408 pt = _conv((absoff % 3600) / 60, "%02d", 409 pt, ptlim); 410 }; 411 continue; 412 case '+': 413 pt = _fmt(tptr->date_fmt, t, pt, ptlim); 414 continue; 415 case '%': 416 /* 417 * X311J/88-090 (4.12.3.5): if conversion char is 418 * undefined, behavior is undefined. Print out the 419 * character itself as printf(3) also does. 420 */ 421 default: 422 break; 423 } 424 } 425 if (pt == ptlim) 426 break; 427 *pt++ = *format; 428 } 429 return pt; 430} 431 432static char * 433_conv(n, format, pt, ptlim) 434 const int n; 435 const char *const format; 436 char *const pt; 437 const char *const ptlim; 438{ 439 char buf[INT_STRLEN_MAXIMUM(int) + 1]; 440 441 (void) sprintf(buf, format, n); 442 return _add(buf, pt, ptlim); 443} 444 445static char * 446_add(str, pt, ptlim) 447 const char *str; 448 char *pt; 449 const char *const ptlim; 450{ 451 while (pt < ptlim && (*pt = *str++) != '\0') 452 ++pt; 453 return pt; 454} 455