strftime.c revision 56756
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 56756 2000-01-28 17:40:42Z joerg $"; 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 "private.h" 34 35#ifndef LIBC_SCCS 36#ifndef lint 37static const char sccsid[] = "@(#)strftime.c 5.4 (Berkeley) 3/14/89"; 38#endif /* !defined lint */ 39#endif /* !defined LIBC_SCCS */ 40 41#include "tzfile.h" 42#include <fcntl.h> 43#include <sys/stat.h> 44#include "timelocal.h" 45 46static char * _add P((const char *, char *, const char *)); 47static char * _conv P((int, const char *, char *, const char *)); 48static char * _fmt P((const char *, const struct tm *, char *, const char *)); 49 50size_t strftime P((char *, size_t, const char *, const struct tm *)); 51 52extern char * tzname[]; 53 54size_t 55strftime(s, maxsize, format, t) 56 char *const s; 57 const size_t maxsize; 58 const char *const format; 59 const struct tm *const t; 60{ 61 char *p; 62 63 tzset(); 64 p = _fmt(((format == NULL) ? "%c" : format), t, s, s + maxsize); 65 if (p == s + maxsize) 66 return 0; 67 *p = '\0'; 68 return p - s; 69} 70 71static char * 72_fmt(format, t, pt, ptlim) 73 const char *format; 74 const struct tm *const t; 75 char *pt; 76 const char *const ptlim; 77{ 78 int Ealternative, Oalternative; 79 80 for ( ; *format; ++format) { 81 if (*format == '%') { 82 Ealternative = 0; 83 Oalternative = 0; 84label: 85 switch (*++format) { 86 case '\0': 87 --format; 88 break; 89 case 'A': 90 pt = _add((t->tm_wday < 0 || t->tm_wday > 6) ? 91 "?" : Locale->weekday[t->tm_wday], 92 pt, ptlim); 93 continue; 94 case 'a': 95 pt = _add((t->tm_wday < 0 || t->tm_wday > 6) ? 96 "?" : Locale->wday[t->tm_wday], 97 pt, ptlim); 98 continue; 99 case 'B': 100 pt = _add((t->tm_mon < 0 || t->tm_mon > 11) ? 101 "?" : (Oalternative ? Locale->alt_month : 102 Locale->month)[t->tm_mon], 103 pt, ptlim); 104 continue; 105 case 'b': 106 case 'h': 107 pt = _add((t->tm_mon < 0 || t->tm_mon > 11) ? 108 "?" : Locale->mon[t->tm_mon], 109 pt, ptlim); 110 continue; 111 case 'C': 112 /* 113 ** %C used to do a... 114 ** _fmt("%a %b %e %X %Y", t); 115 ** ...whereas now POSIX 1003.2 calls for 116 ** something completely different. 117 ** (ado, 5/24/93) 118 */ 119 pt = _conv((t->tm_year + TM_YEAR_BASE) / 100, 120 "%02d", pt, ptlim); 121 continue; 122 case 'c': 123 pt = _fmt(Locale->c_fmt, t, pt, ptlim); 124 continue; 125 case 'D': 126 pt = _fmt("%m/%d/%y", t, pt, ptlim); 127 continue; 128 case 'd': 129 pt = _conv(t->tm_mday, "%02d", pt, ptlim); 130 continue; 131 case 'E': 132 if (Ealternative || Oalternative) 133 break; 134 Ealternative++; 135 goto label; 136 case 'O': 137 /* 138 ** POSIX locale extensions, a la 139 ** Arnold Robbins' strftime version 3.0. 140 ** The sequences 141 ** %Ec %EC %Ex %EX %Ey %EY 142 ** %Od %oe %OH %OI %Om %OM 143 ** %OS %Ou %OU %OV %Ow %OW %Oy 144 ** are supposed to provide alternate 145 ** representations. 146 ** (ado, 5/24/93) 147 ** 148 ** FreeBSD extensions 149 ** %OB %Ef %EF 150 */ 151 if (Ealternative || Oalternative) 152 break; 153 Oalternative++; 154 goto label; 155 case 'e': 156 pt = _conv(t->tm_mday, "%2d", pt, ptlim); 157 continue; 158 case 'f': 159 if (!Ealternative) 160 break; 161 pt = _fmt(Locale->Ef_fmt, t, pt, ptlim); 162 continue; 163 case 'F': 164 if (!Ealternative) 165 break; 166 pt = _fmt(Locale->EF_fmt, t, pt, ptlim); 167 continue; 168 case 'H': 169 pt = _conv(t->tm_hour, "%02d", pt, ptlim); 170 continue; 171 case 'I': 172 pt = _conv((t->tm_hour % 12) ? 173 (t->tm_hour % 12) : 12, 174 "%02d", pt, ptlim); 175 continue; 176 case 'j': 177 pt = _conv(t->tm_yday + 1, "%03d", pt, ptlim); 178 continue; 179 case 'k': 180 /* 181 ** This used to be... 182 ** _conv(t->tm_hour % 12 ? 183 ** t->tm_hour % 12 : 12, 2, ' '); 184 ** ...and has been changed to the below to 185 ** match SunOS 4.1.1 and Arnold Robbins' 186 ** strftime version 3.0. That is, "%k" and 187 ** "%l" have been swapped. 188 ** (ado, 5/24/93) 189 */ 190 pt = _conv(t->tm_hour, "%2d", pt, ptlim); 191 continue; 192#ifdef KITCHEN_SINK 193 case 'K': 194 /* 195 ** After all this time, still unclaimed! 196 */ 197 pt = _add("kitchen sink", pt, ptlim); 198 continue; 199#endif /* defined KITCHEN_SINK */ 200 case 'l': 201 /* 202 ** This used to be... 203 ** _conv(t->tm_hour, 2, ' '); 204 ** ...and has been changed to the below to 205 ** match SunOS 4.1.1 and Arnold Robbin's 206 ** strftime version 3.0. That is, "%k" and 207 ** "%l" have been swapped. 208 ** (ado, 5/24/93) 209 */ 210 pt = _conv((t->tm_hour % 12) ? 211 (t->tm_hour % 12) : 12, 212 "%2d", pt, ptlim); 213 continue; 214 case 'M': 215 pt = _conv(t->tm_min, "%02d", pt, ptlim); 216 continue; 217 case 'm': 218 pt = _conv(t->tm_mon + 1, "%02d", pt, ptlim); 219 continue; 220 case 'n': 221 pt = _add("\n", pt, ptlim); 222 continue; 223 case 'p': 224 pt = _add((t->tm_hour >= 12) ? 225 Locale->pm : 226 Locale->am, 227 pt, ptlim); 228 continue; 229 case 'R': 230 pt = _fmt("%H:%M", t, pt, ptlim); 231 continue; 232 case 'r': 233 pt = _fmt("%I:%M:%S %p", t, pt, ptlim); 234 continue; 235 case 'S': 236 pt = _conv(t->tm_sec, "%02d", pt, ptlim); 237 continue; 238 case 's': 239 { 240 struct tm tm; 241 char buf[INT_STRLEN_MAXIMUM( 242 time_t) + 1]; 243 time_t mkt; 244 245 tm = *t; 246 mkt = mktime(&tm); 247 if (TYPE_SIGNED(time_t)) 248 (void) sprintf(buf, "%ld", 249 (long) mkt); 250 else (void) sprintf(buf, "%lu", 251 (unsigned long) mkt); 252 pt = _add(buf, pt, ptlim); 253 } 254 continue; 255 case 'T': 256 pt = _fmt("%H:%M:%S", t, pt, ptlim); 257 continue; 258 case 't': 259 pt = _add("\t", pt, ptlim); 260 continue; 261 case 'U': 262 pt = _conv((t->tm_yday + 7 - t->tm_wday) / 7, 263 "%02d", pt, ptlim); 264 continue; 265 case 'u': 266 /* 267 ** From Arnold Robbins' strftime version 3.0: 268 ** "ISO 8601: Weekday as a decimal number 269 ** [1 (Monday) - 7]" 270 ** (ado, 5/24/93) 271 */ 272 pt = _conv((t->tm_wday == 0) ? 7 : t->tm_wday, 273 "%d", pt, ptlim); 274 continue; 275 case 'V': /* ISO 8601 week number */ 276 case 'G': /* ISO 8601 year (four digits) */ 277 case 'g': /* ISO 8601 year (two digits) */ 278/* 279** From Arnold Robbins' strftime version 3.0: "the week number of the 280** year (the first Monday as the first day of week 1) as a decimal number 281** (01-53)." 282** (ado, 1993-05-24) 283** 284** From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn: 285** "Week 01 of a year is per definition the first week which has the 286** Thursday in this year, which is equivalent to the week which contains 287** the fourth day of January. In other words, the first week of a new year 288** is the week which has the majority of its days in the new year. Week 01 289** might also contain days from the previous year and the week before week 290** 01 of a year is the last week (52 or 53) of the previous year even if 291** it contains days from the new year. A week starts with Monday (day 1) 292** and ends with Sunday (day 7). For example, the first week of the year 293** 1997 lasts from 1996-12-30 to 1997-01-05..." 294** (ado, 1996-01-02) 295*/ 296 { 297 int year; 298 int yday; 299 int wday; 300 int w; 301 302 year = t->tm_year + TM_YEAR_BASE; 303 yday = t->tm_yday; 304 wday = t->tm_wday; 305 for ( ; ; ) { 306 int len; 307 int bot; 308 int top; 309 310 len = isleap(year) ? 311 DAYSPERLYEAR : 312 DAYSPERNYEAR; 313 /* 314 ** What yday (-3 ... 3) does 315 ** the ISO year begin on? 316 */ 317 bot = ((yday + 11 - wday) % 318 DAYSPERWEEK) - 3; 319 /* 320 ** What yday does the NEXT 321 ** ISO year begin on? 322 */ 323 top = bot - 324 (len % DAYSPERWEEK); 325 if (top < -3) 326 top += DAYSPERWEEK; 327 top += len; 328 if (yday >= top) { 329 ++year; 330 w = 1; 331 break; 332 } 333 if (yday >= bot) { 334 w = 1 + ((yday - bot) / 335 DAYSPERWEEK); 336 break; 337 } 338 --year; 339 yday += isleap(year) ? 340 DAYSPERLYEAR : 341 DAYSPERNYEAR; 342 } 343#ifdef XPG4_1994_04_09 344 if ((w == 52 345 && t->tm_mon == TM_JANUARY) 346 || (w == 1 347 && t->tm_mon == TM_DECEMBER)) 348 w = 53; 349#endif /* defined XPG4_1994_04_09 */ 350 if (*format == 'V') 351 pt = _conv(w, "%02d", 352 pt, ptlim); 353 else if (*format == 'g') { 354 pt = _conv(year % 100, "%02d", 355 pt, ptlim); 356 } else pt = _conv(year, "%04d", 357 pt, ptlim); 358 } 359 continue; 360 case 'v': 361 /* 362 ** From Arnold Robbins' strftime version 3.0: 363 ** "date as dd-bbb-YYYY" 364 ** (ado, 5/24/93) 365 */ 366 pt = _fmt("%e-%b-%Y", t, pt, ptlim); 367 continue; 368 case 'W': 369 pt = _conv((t->tm_yday + 7 - 370 (t->tm_wday ? 371 (t->tm_wday - 1) : 6)) / 7, 372 "%02d", pt, ptlim); 373 continue; 374 case 'w': 375 pt = _conv(t->tm_wday, "%d", pt, ptlim); 376 continue; 377 case 'X': 378 pt = _fmt(Locale->X_fmt, t, pt, ptlim); 379 continue; 380 case 'x': 381 pt = _fmt(Locale->x_fmt, t, pt, ptlim); 382 continue; 383 case 'y': 384 pt = _conv((t->tm_year + TM_YEAR_BASE) % 100, 385 "%02d", pt, ptlim); 386 continue; 387 case 'Y': 388 pt = _conv(t->tm_year + TM_YEAR_BASE, "%04d", 389 pt, ptlim); 390 continue; 391 case 'Z': 392 if (t->tm_zone != NULL) 393 pt = _add(t->tm_zone, pt, ptlim); 394 else 395 if (t->tm_isdst == 0 || t->tm_isdst == 1) { 396 pt = _add(tzname[t->tm_isdst], 397 pt, ptlim); 398 } else pt = _add("?", pt, ptlim); 399 continue; 400 case 'z': 401 { 402 long absoff; 403 if (t->tm_gmtoff >= 0) { 404 absoff = t->tm_gmtoff; 405 pt = _add("+", pt, ptlim); 406 } else { 407 absoff = -t->tm_gmtoff; 408 pt = _add("-", pt, ptlim); 409 } 410 pt = _conv(absoff / 3600, "%02d", 411 pt, ptlim); 412 pt = _conv((absoff % 3600) / 60, "%02d", 413 pt, ptlim); 414 }; 415 continue; 416 case '+': 417 pt = _fmt(Locale->date_fmt, t, pt, ptlim); 418 continue; 419 case '%': 420 /* 421 * X311J/88-090 (4.12.3.5): if conversion char is 422 * undefined, behavior is undefined. Print out the 423 * character itself as printf(3) also does. 424 */ 425 default: 426 break; 427 } 428 } 429 if (pt == ptlim) 430 break; 431 *pt++ = *format; 432 } 433 return pt; 434} 435 436static char * 437_conv(n, format, pt, ptlim) 438 const int n; 439 const char *const format; 440 char *const pt; 441 const char *const ptlim; 442{ 443 char buf[INT_STRLEN_MAXIMUM(int) + 1]; 444 445 (void) sprintf(buf, format, n); 446 return _add(buf, pt, ptlim); 447} 448 449static char * 450_add(str, pt, ptlim) 451 const char *str; 452 char *pt; 453 const char *const ptlim; 454{ 455 while (pt < ptlim && (*pt = *str++) != '\0') 456 ++pt; 457 return pt; 458} 459