strftime.c revision 1.11
1 /* $NetBSD: strftime.c,v 1.11 2000/09/07 12:45:03 taca Exp $ */ 2 3 /* 4 * Copyright (c) 1989 The Regents of the University of California. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #include <sys/cdefs.h> 37 #if defined(LIBC_SCCS) && !defined(lint) 38 #if 0 39 static char *sccsid = "@(#)strftime.c 5.11 (Berkeley) 2/24/91"; 40 #else 41 __RCSID("$NetBSD: strftime.c,v 1.11 2000/09/07 12:45:03 taca Exp $"); 42 #endif 43 #endif /* LIBC_SCCS and not lint */ 44 45 #include "namespace.h" 46 #include "private.h" 47 #include <sys/localedef.h> 48 #include <locale.h> 49 #include <string.h> 50 #include <tzfile.h> 51 #include <time.h> 52 53 static int _add __P((const char *, char **, const char *)); 54 static int _conv __P((int, int, int, char **, const char *)); 55 static int _secs __P((const struct tm *, char **, const char *)); 56 static size_t _fmt __P((const char *, const struct tm *, char **, 57 const char *)); 58 59 size_t 60 strftime(s, maxsize, format, t) 61 char *s; 62 size_t maxsize; 63 const char *format; 64 const struct tm *t; 65 { 66 char *pt; 67 68 tzset(); 69 if (maxsize < 1) 70 return (0); 71 72 pt = s; 73 if (_fmt(format, t, &pt, s + maxsize)) { 74 *pt = '\0'; 75 return (pt - s); 76 } else 77 return (0); 78 } 79 80 #define SUN_WEEK(t) (((t)->tm_yday + 7 - \ 81 ((t)->tm_wday)) / 7) 82 #define MON_WEEK(t) (((t)->tm_yday + 7 - \ 83 ((t)->tm_wday ? (t)->tm_wday - 1 : 6)) / 7) 84 85 static size_t 86 _fmt(format, t, pt, ptlim) 87 const char *format; 88 const struct tm *t; 89 char **pt; 90 const char * const ptlim; 91 { 92 for (; *format; ++format) { 93 if (*format == '%') { 94 ++format; 95 if (*format == 'E') { 96 /* Alternate Era */ 97 ++format; 98 } else if (*format == 'O') { 99 /* Alternate numeric symbols */ 100 ++format; 101 } 102 switch (*format) { 103 case '\0': 104 --format; 105 break; 106 case 'A': 107 if (t->tm_wday < 0 || t->tm_wday > 6) 108 return (0); 109 if (!_add(_CurrentTimeLocale->day[t->tm_wday], 110 pt, ptlim)) 111 return (0); 112 continue; 113 114 case 'a': 115 if (t->tm_wday < 0 || t->tm_wday > 6) 116 return (0); 117 if (!_add(_CurrentTimeLocale->abday[t->tm_wday], 118 pt, ptlim)) 119 return (0); 120 continue; 121 case 'B': 122 if (t->tm_mon < 0 || t->tm_mon > 11) 123 return (0); 124 if (!_add(_CurrentTimeLocale->mon[t->tm_mon], 125 pt, ptlim)) 126 return (0); 127 continue; 128 case 'b': 129 case 'h': 130 if (t->tm_mon < 0 || t->tm_mon > 11) 131 return (0); 132 if (!_add(_CurrentTimeLocale->abmon[t->tm_mon], 133 pt, ptlim)) 134 return (0); 135 continue; 136 case 'C': 137 if (!_conv((t->tm_year + TM_YEAR_BASE) / 100, 138 2, '0', pt, ptlim)) 139 return (0); 140 continue; 141 case 'c': 142 if (!_fmt(_CurrentTimeLocale->d_t_fmt, t, pt, 143 ptlim)) 144 return (0); 145 continue; 146 case 'D': 147 if (!_fmt("%m/%d/%y", t, pt, ptlim)) 148 return (0); 149 continue; 150 case 'd': 151 if (!_conv(t->tm_mday, 2, '0', pt, ptlim)) 152 return (0); 153 continue; 154 case 'e': 155 if (!_conv(t->tm_mday, 2, ' ', pt, ptlim)) 156 return (0); 157 continue; 158 case 'F': 159 if (!_fmt("%Y-%m-%d", t, pt, ptlim)) 160 return (0); 161 continue; 162 case 'H': 163 if (!_conv(t->tm_hour, 2, '0', pt, ptlim)) 164 return (0); 165 continue; 166 case 'I': 167 if (!_conv(t->tm_hour % 12 ? 168 t->tm_hour % 12 : 12, 2, '0', pt, ptlim)) 169 return (0); 170 continue; 171 case 'j': 172 if (!_conv(t->tm_yday + 1, 3, '0', pt, ptlim)) 173 return (0); 174 continue; 175 case 'k': 176 if (!_conv(t->tm_hour, 2, ' ', pt, ptlim)) 177 return (0); 178 continue; 179 case 'l': 180 if (!_conv(t->tm_hour % 12 ? 181 t->tm_hour % 12: 12, 2, ' ', pt, ptlim)) 182 return (0); 183 continue; 184 case 'M': 185 if (!_conv(t->tm_min, 2, '0', pt, ptlim)) 186 return (0); 187 continue; 188 case 'm': 189 if (!_conv(t->tm_mon + 1, 2, '0', pt, ptlim)) 190 return (0); 191 continue; 192 case 'n': 193 if (!_add("\n", pt, ptlim)) 194 return (0); 195 continue; 196 case 'p': 197 if (!_add(_CurrentTimeLocale->am_pm[t->tm_hour 198 >= 12], pt, ptlim)) 199 return (0); 200 continue; 201 case 'R': 202 if (!_fmt("%H:%M", t, pt, ptlim)) 203 return (0); 204 continue; 205 case 'r': 206 if (!_fmt(_CurrentTimeLocale->t_fmt_ampm, t, pt, 207 ptlim)) 208 return (0); 209 continue; 210 case 'S': 211 if (!_conv(t->tm_sec, 2, '0', pt, ptlim)) 212 return (0); 213 continue; 214 case 's': 215 if (!_secs(t, pt, ptlim)) 216 return (0); 217 continue; 218 case 'T': 219 if (!_fmt("%H:%M:%S", t, pt, ptlim)) 220 return (0); 221 continue; 222 case 't': 223 if (!_add("\t", pt, ptlim)) 224 return (0); 225 continue; 226 case 'U': 227 if (!_conv(SUN_WEEK(t), 2, '0', pt, ptlim)) 228 return (0); 229 continue; 230 case 'u': 231 if (!_conv(t->tm_wday ? t->tm_wday : 7, 1, '0', 232 pt, ptlim)) 233 return (0); 234 continue; 235 case 'V': /* ISO 8601 week number */ 236 case 'G': /* ISO 8601 year (four digits) */ 237 case 'g': /* ISO 8601 year (two digits) */ 238 /* 239 ** From Arnold Robbins' strftime version 3.0: "the week number of the 240 ** year (the first Monday as the first day of week 1) as a decimal number 241 ** (01-53)." 242 ** (ado, 1993-05-24) 243 ** 244 ** From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn: 245 ** "Week 01 of a year is per definition the first week which has the 246 ** Thursday in this year, which is equivalent to the week which contains 247 ** the fourth day of January. In other words, the first week of a new year 248 ** is the week which has the majority of its days in the new year. Week 01 249 ** might also contain days from the previous year and the week before week 250 ** 01 of a year is the last week (52 or 53) of the previous year even if 251 ** it contains days from the new year. A week starts with Monday (day 1) 252 ** and ends with Sunday (day 7). For example, the first week of the year 253 ** 1997 lasts from 1996-12-30 to 1997-01-05..." 254 ** (ado, 1996-01-02) 255 */ 256 { 257 int year; 258 int yday; 259 int wday; 260 int w; 261 262 year = t->tm_year + TM_YEAR_BASE; 263 yday = t->tm_yday; 264 wday = t->tm_wday; 265 for ( ; ; ) { 266 int len; 267 int bot; 268 int top; 269 270 len = isleap(year) ? 271 DAYSPERLYEAR : 272 DAYSPERNYEAR; 273 /* 274 ** What yday (-3 ... 3) does 275 ** the ISO year begin on? 276 */ 277 bot = ((yday + 11 - wday) % 278 DAYSPERWEEK) - 3; 279 /* 280 ** What yday does the NEXT 281 ** ISO year begin on? 282 */ 283 top = bot - 284 (len % DAYSPERWEEK); 285 if (top < -3) 286 top += DAYSPERWEEK; 287 top += len; 288 if (yday >= top) { 289 ++year; 290 w = 1; 291 break; 292 } 293 if (yday >= bot) { 294 w = 1 + ((yday - bot) / 295 DAYSPERWEEK); 296 break; 297 } 298 --year; 299 yday += isleap(year) ? 300 DAYSPERLYEAR : 301 DAYSPERNYEAR; 302 } 303 #ifdef XPG4_1994_04_09 304 if ((w == 52 305 && t->tm_mon == TM_JANUARY) 306 || (w == 1 307 && t->tm_mon == TM_DECEMBER)) 308 w = 53; 309 #endif /* defined XPG4_1994_04_09 */ 310 if (*format == 'V') { 311 if (!_conv(w, 2, '0', 312 pt, ptlim)) 313 return (0); 314 } else if (*format == 'g') { 315 if (!_conv(year % 100, 2, '0', 316 pt, ptlim)) 317 return (0); 318 } else if (!_conv(year, 4, '0', 319 pt, ptlim)) 320 return (0); 321 } 322 continue; 323 case 'W': 324 if (!_conv(MON_WEEK(t), 2, '0', pt, ptlim)) 325 return (0); 326 continue; 327 case 'w': 328 if (!_conv(t->tm_wday, 1, '0', pt, ptlim)) 329 return (0); 330 continue; 331 case 'x': 332 if (!_fmt(_CurrentTimeLocale->d_fmt, t, pt, 333 ptlim)) 334 return (0); 335 continue; 336 case 'X': 337 if (!_fmt(_CurrentTimeLocale->t_fmt, t, pt, 338 ptlim)) 339 return (0); 340 continue; 341 case 'y': 342 if (!_conv((t->tm_year + TM_YEAR_BASE) % 100, 343 2, '0', pt, ptlim)) 344 return (0); 345 continue; 346 case 'Y': 347 if (!_conv((t->tm_year + TM_YEAR_BASE), 4, '0', 348 pt, ptlim)) 349 return (0); 350 continue; 351 case 'Z': 352 #ifdef TM_ZONE 353 if (t->TM_ZONE != NULL) { 354 if (!_add(t->TM_ZONE, pt, ptlim)) 355 return (0); 356 } else 357 #endif /* TM_ZONE */ 358 if (tzname[t->tm_isdst ? 1 : 0] && 359 !_add(tzname[t->tm_isdst ? 1 : 0], pt, 360 ptlim)) 361 return (0); 362 continue; 363 case '%': 364 /* 365 * X311J/88-090 (4.12.3.5): if conversion char is 366 * undefined, behavior is undefined. Print out the 367 * character itself as printf(3) does. 368 */ 369 default: 370 break; 371 } 372 } 373 if (*pt == ptlim) 374 return (0); 375 *(*pt)++ = *format; 376 } 377 return (ptlim - *pt); 378 } 379 380 static int 381 _secs(t, pt, ptlim) 382 const struct tm *t; 383 char **pt; 384 const char * const ptlim; 385 { 386 char buf[15]; 387 time_t s; 388 char *p; 389 struct tm tmp; 390 391 buf[sizeof (buf) - 1] = '\0'; 392 /* Make a copy, mktime(3) modifies the tm struct. */ 393 tmp = *t; 394 s = mktime(&tmp); 395 for (p = buf + sizeof(buf) - 2; s > 0 && p > buf; s /= 10) 396 *p-- = (char)(s % 10 + '0'); 397 return (_add(++p, pt, ptlim)); 398 } 399 400 static int 401 _conv(n, digits, pad, pt, ptlim) 402 int n, digits; 403 int pad; 404 char **pt; 405 const char * const ptlim; 406 { 407 char buf[10]; 408 char *p; 409 410 buf[sizeof (buf) - 1] = '\0'; 411 p = buf + sizeof(buf) - 2; 412 do { 413 *p-- = n % 10 + '0'; 414 n /= 10; 415 --digits; 416 } while (n > 0 && p > buf); 417 while (p > buf && digits-- > 0) 418 *p-- = pad; 419 return (_add(++p, pt, ptlim)); 420 } 421 422 static int 423 _add(str, pt, ptlim) 424 const char *str; 425 char **pt; 426 const char * const ptlim; 427 { 428 429 for (;; ++(*pt)) { 430 if (*pt == ptlim) 431 return (0); 432 if ((**pt = *str++) == '\0') 433 return (1); 434 } 435 } 436
Indexes created Sat Sep 27 14:09:57 GMT 2025