strftime.c revision 72168
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 72168 2001-02-08 17:08:13Z phantom $"; 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 /* NOTE: c_fmt is intentionally ignored */ 127 pt = _fmt("%a %Ef %T %Y", t, pt, ptlim); 128 continue; 129 case 'D': 130 pt = _fmt("%m/%d/%y", t, pt, ptlim); 131 continue; 132 case 'd': 133 pt = _conv(t->tm_mday, "%02d", pt, ptlim); 134 continue; 135 case 'E': 136 if (Ealternative || Oalternative) 137 break; 138 Ealternative++; 139 goto label; 140 case 'O': 141 /* 142 ** POSIX locale extensions, a la 143 ** Arnold Robbins' strftime version 3.0. 144 ** The sequences 145 ** %Ec %EC %Ex %EX %Ey %EY 146 ** %Od %oe %OH %OI %Om %OM 147 ** %OS %Ou %OU %OV %Ow %OW %Oy 148 ** are supposed to provide alternate 149 ** representations. 150 ** (ado, 5/24/93) 151 ** 152 ** FreeBSD extensions 153 ** %OB %Ef %EF 154 */ 155 if (Ealternative || Oalternative) 156 break; 157 Oalternative++; 158 goto label; 159 case 'e': 160 pt = _conv(t->tm_mday, "%2d", pt, ptlim); 161 continue; 162 case 'f': 163 if (!Ealternative) 164 break; 165 pt = _fmt(tptr->Ef_fmt, t, pt, ptlim); 166 continue; 167 case 'F': 168 if (!Ealternative) 169 break; 170 pt = _fmt(tptr->EF_fmt, t, pt, ptlim); 171 continue; 172 case 'H': 173 pt = _conv(t->tm_hour, "%02d", pt, ptlim); 174 continue; 175 case 'I': 176 pt = _conv((t->tm_hour % 12) ? 177 (t->tm_hour % 12) : 12, 178 "%02d", pt, ptlim); 179 continue; 180 case 'j': 181 pt = _conv(t->tm_yday + 1, "%03d", pt, ptlim); 182 continue; 183 case 'k': 184 /* 185 ** This used to be... 186 ** _conv(t->tm_hour % 12 ? 187 ** t->tm_hour % 12 : 12, 2, ' '); 188 ** ...and has been changed to the below to 189 ** match SunOS 4.1.1 and Arnold Robbins' 190 ** strftime version 3.0. That is, "%k" and 191 ** "%l" have been swapped. 192 ** (ado, 5/24/93) 193 */ 194 pt = _conv(t->tm_hour, "%2d", pt, ptlim); 195 continue; 196#ifdef KITCHEN_SINK 197 case 'K': 198 /* 199 ** After all this time, still unclaimed! 200 */ 201 pt = _add("kitchen sink", pt, ptlim); 202 continue; 203#endif /* defined KITCHEN_SINK */ 204 case 'l': 205 /* 206 ** This used to be... 207 ** _conv(t->tm_hour, 2, ' '); 208 ** ...and has been changed to the below to 209 ** match SunOS 4.1.1 and Arnold Robbin's 210 ** strftime version 3.0. That is, "%k" and 211 ** "%l" have been swapped. 212 ** (ado, 5/24/93) 213 */ 214 pt = _conv((t->tm_hour % 12) ? 215 (t->tm_hour % 12) : 12, 216 "%2d", pt, ptlim); 217 continue; 218 case 'M': 219 pt = _conv(t->tm_min, "%02d", pt, ptlim); 220 continue; 221 case 'm': 222 pt = _conv(t->tm_mon + 1, "%02d", pt, ptlim); 223 continue; 224 case 'n': 225 pt = _add("\n", pt, ptlim); 226 continue; 227 case 'p': 228 pt = _add((t->tm_hour >= 12) ? 229 tptr->pm : 230 tptr->am, 231 pt, ptlim); 232 continue; 233 case 'R': 234 pt = _fmt("%H:%M", t, pt, ptlim); 235 continue; 236 case 'r': 237 pt = _fmt("%I:%M:%S %p", t, pt, ptlim); 238 continue; 239 case 'S': 240 pt = _conv(t->tm_sec, "%02d", pt, ptlim); 241 continue; 242 case 's': 243 { 244 struct tm tm; 245 char buf[INT_STRLEN_MAXIMUM( 246 time_t) + 1]; 247 time_t mkt; 248 249 tm = *t; 250 mkt = mktime(&tm); 251 if (TYPE_SIGNED(time_t)) 252 (void) sprintf(buf, "%ld", 253 (long) mkt); 254 else (void) sprintf(buf, "%lu", 255 (unsigned long) mkt); 256 pt = _add(buf, pt, ptlim); 257 } 258 continue; 259 case 'T': 260 pt = _fmt("%H:%M:%S", t, pt, ptlim); 261 continue; 262 case 't': 263 pt = _add("\t", pt, ptlim); 264 continue; 265 case 'U': 266 pt = _conv((t->tm_yday + 7 - t->tm_wday) / 7, 267 "%02d", pt, ptlim); 268 continue; 269 case 'u': 270 /* 271 ** From Arnold Robbins' strftime version 3.0: 272 ** "ISO 8601: Weekday as a decimal number 273 ** [1 (Monday) - 7]" 274 ** (ado, 5/24/93) 275 */ 276 pt = _conv((t->tm_wday == 0) ? 7 : t->tm_wday, 277 "%d", pt, ptlim); 278 continue; 279 case 'V': /* ISO 8601 week number */ 280 case 'G': /* ISO 8601 year (four digits) */ 281 case 'g': /* ISO 8601 year (two digits) */ 282/* 283** From Arnold Robbins' strftime version 3.0: "the week number of the 284** year (the first Monday as the first day of week 1) as a decimal number 285** (01-53)." 286** (ado, 1993-05-24) 287** 288** From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn: 289** "Week 01 of a year is per definition the first week which has the 290** Thursday in this year, which is equivalent to the week which contains 291** the fourth day of January. In other words, the first week of a new year 292** is the week which has the majority of its days in the new year. Week 01 293** might also contain days from the previous year and the week before week 294** 01 of a year is the last week (52 or 53) of the previous year even if 295** it contains days from the new year. A week starts with Monday (day 1) 296** and ends with Sunday (day 7). For example, the first week of the year 297** 1997 lasts from 1996-12-30 to 1997-01-05..." 298** (ado, 1996-01-02) 299*/ 300 { 301 int year; 302 int yday; 303 int wday; 304 int w; 305 306 year = t->tm_year + TM_YEAR_BASE; 307 yday = t->tm_yday; 308 wday = t->tm_wday; 309 for ( ; ; ) { 310 int len; 311 int bot; 312 int top; 313 314 len = isleap(year) ? 315 DAYSPERLYEAR : 316 DAYSPERNYEAR; 317 /* 318 ** What yday (-3 ... 3) does 319 ** the ISO year begin on? 320 */ 321 bot = ((yday + 11 - wday) % 322 DAYSPERWEEK) - 3; 323 /* 324 ** What yday does the NEXT 325 ** ISO year begin on? 326 */ 327 top = bot - 328 (len % DAYSPERWEEK); 329 if (top < -3) 330 top += DAYSPERWEEK; 331 top += len; 332 if (yday >= top) { 333 ++year; 334 w = 1; 335 break; 336 } 337 if (yday >= bot) { 338 w = 1 + ((yday - bot) / 339 DAYSPERWEEK); 340 break; 341 } 342 --year; 343 yday += isleap(year) ? 344 DAYSPERLYEAR : 345 DAYSPERNYEAR; 346 } 347#ifdef XPG4_1994_04_09 348 if ((w == 52 349 && t->tm_mon == TM_JANUARY) 350 || (w == 1 351 && t->tm_mon == TM_DECEMBER)) 352 w = 53; 353#endif /* defined XPG4_1994_04_09 */ 354 if (*format == 'V') 355 pt = _conv(w, "%02d", 356 pt, ptlim); 357 else if (*format == 'g') { 358 pt = _conv(year % 100, "%02d", 359 pt, ptlim); 360 } else pt = _conv(year, "%04d", 361 pt, ptlim); 362 } 363 continue; 364 case 'v': 365 /* 366 ** From Arnold Robbins' strftime version 3.0: 367 ** "date as dd-bbb-YYYY" 368 ** (ado, 5/24/93) 369 */ 370 pt = _fmt("%e-%b-%Y", t, pt, ptlim); 371 continue; 372 case 'W': 373 pt = _conv((t->tm_yday + 7 - 374 (t->tm_wday ? 375 (t->tm_wday - 1) : 6)) / 7, 376 "%02d", pt, ptlim); 377 continue; 378 case 'w': 379 pt = _conv(t->tm_wday, "%d", pt, ptlim); 380 continue; 381 case 'X': 382 pt = _fmt(tptr->X_fmt, t, pt, ptlim); 383 continue; 384 case 'x': 385 pt = _fmt(tptr->x_fmt, t, pt, ptlim); 386 continue; 387 case 'y': 388 pt = _conv((t->tm_year + TM_YEAR_BASE) % 100, 389 "%02d", pt, ptlim); 390 continue; 391 case 'Y': 392 pt = _conv(t->tm_year + TM_YEAR_BASE, "%04d", 393 pt, ptlim); 394 continue; 395 case 'Z': 396 if (t->tm_zone != NULL) 397 pt = _add(t->tm_zone, pt, ptlim); 398 else 399 if (t->tm_isdst == 0 || t->tm_isdst == 1) { 400 pt = _add(tzname[t->tm_isdst], 401 pt, ptlim); 402 } else pt = _add("?", pt, ptlim); 403 continue; 404 case 'z': 405 { 406 long absoff; 407 if (t->tm_gmtoff >= 0) { 408 absoff = t->tm_gmtoff; 409 pt = _add("+", pt, ptlim); 410 } else { 411 absoff = -t->tm_gmtoff; 412 pt = _add("-", pt, ptlim); 413 } 414 pt = _conv(absoff / 3600, "%02d", 415 pt, ptlim); 416 pt = _conv((absoff % 3600) / 60, "%02d", 417 pt, ptlim); 418 }; 419 continue; 420 case '+': 421 pt = _fmt(tptr->date_fmt, t, pt, ptlim); 422 continue; 423 case '%': 424 /* 425 * X311J/88-090 (4.12.3.5): if conversion char is 426 * undefined, behavior is undefined. Print out the 427 * character itself as printf(3) also does. 428 */ 429 default: 430 break; 431 } 432 } 433 if (pt == ptlim) 434 break; 435 *pt++ = *format; 436 } 437 return pt; 438} 439 440static char * 441_conv(n, format, pt, ptlim) 442 const int n; 443 const char *const format; 444 char *const pt; 445 const char *const ptlim; 446{ 447 char buf[INT_STRLEN_MAXIMUM(int) + 1]; 448 449 (void) snprintf(buf, sizeof(buf), format, n); 450 return _add(buf, pt, ptlim); 451} 452 453static char * 454_add(str, pt, ptlim) 455 const char *str; 456 char *pt; 457 const char *const ptlim; 458{ 459 while (pt < ptlim && (*pt = *str++) != '\0') 460 ++pt; 461 return pt; 462} 463