strftime.c revision 1.9
1 /* $NetBSD: strftime.c,v 1.9 1999/11/05 19:21:12 erh 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 1.9 1999/11/05 19:21:12 erh Exp $"); 42 #endif 43 #endif /* LIBC_SCCS and not lint */ 44 45 #include "namespace.h" 46 #include <sys/localedef.h> 47 #include <locale.h> 48 #include <string.h> 49 #include <tzfile.h> 50 #include <time.h> 51 52 static int _add __P((const char *, char **, const char *)); 53 static int _conv __P((int, int, int, char **, const char *)); 54 static int _secs __P((const struct tm *, char **, const char *)); 55 static size_t _fmt __P((const char *, const struct tm *, char **, 56 const char *)); 57 58 size_t 59 strftime(s, maxsize, format, t) 60 char *s; 61 size_t maxsize; 62 const char *format; 63 const struct tm *t; 64 { 65 char *pt; 66 67 tzset(); 68 if (maxsize < 1) 69 return (0); 70 71 pt = s; 72 if (_fmt(format, t, &pt, s + maxsize)) { 73 *pt = '\0'; 74 return (pt - s); 75 } else 76 return (0); 77 } 78 79 #define SUN_WEEK(t) (((t)->tm_yday + 7 - \ 80 ((t)->tm_wday)) / 7) 81 #define MON_WEEK(t) (((t)->tm_yday + 7 - \ 82 ((t)->tm_wday ? (t)->tm_wday - 1 : 6)) / 7) 83 84 static size_t 85 _fmt(format, t, pt, ptlim) 86 const char *format; 87 const struct tm *t; 88 char **pt; 89 const char * const ptlim; 90 { 91 for (; *format; ++format) { 92 if (*format == '%') { 93 ++format; 94 if (*format == 'E') { 95 /* Alternate Era */ 96 ++format; 97 } else if (*format == 'O') { 98 /* Alternate numeric symbols */ 99 ++format; 100 } 101 switch (*format) { 102 case '\0': 103 --format; 104 break; 105 case 'A': 106 if (t->tm_wday < 0 || t->tm_wday > 6) 107 return (0); 108 if (!_add(_CurrentTimeLocale->day[t->tm_wday], 109 pt, ptlim)) 110 return (0); 111 continue; 112 113 case 'a': 114 if (t->tm_wday < 0 || t->tm_wday > 6) 115 return (0); 116 if (!_add(_CurrentTimeLocale->abday[t->tm_wday], 117 pt, ptlim)) 118 return (0); 119 continue; 120 case 'B': 121 if (t->tm_mon < 0 || t->tm_mon > 11) 122 return (0); 123 if (!_add(_CurrentTimeLocale->mon[t->tm_mon], 124 pt, ptlim)) 125 return (0); 126 continue; 127 case 'b': 128 case 'h': 129 if (t->tm_mon < 0 || t->tm_mon > 11) 130 return (0); 131 if (!_add(_CurrentTimeLocale->abmon[t->tm_mon], 132 pt, ptlim)) 133 return (0); 134 continue; 135 case 'C': 136 if (!_conv((t->tm_year + TM_YEAR_BASE) / 100, 137 2, '0', pt, ptlim)) 138 return (0); 139 continue; 140 case 'c': 141 if (!_fmt(_CurrentTimeLocale->d_t_fmt, t, pt, 142 ptlim)) 143 return (0); 144 continue; 145 case 'D': 146 if (!_fmt("%m/%d/%y", t, pt, ptlim)) 147 return (0); 148 continue; 149 case 'd': 150 if (!_conv(t->tm_mday, 2, '0', pt, ptlim)) 151 return (0); 152 continue; 153 case 'e': 154 if (!_conv(t->tm_mday, 2, ' ', pt, ptlim)) 155 return (0); 156 continue; 157 case 'H': 158 if (!_conv(t->tm_hour, 2, '0', pt, ptlim)) 159 return (0); 160 continue; 161 case 'I': 162 if (!_conv(t->tm_hour % 12 ? 163 t->tm_hour % 12 : 12, 2, '0', pt, ptlim)) 164 return (0); 165 continue; 166 case 'j': 167 if (!_conv(t->tm_yday + 1, 3, '0', pt, ptlim)) 168 return (0); 169 continue; 170 case 'k': 171 if (!_conv(t->tm_hour, 2, ' ', pt, ptlim)) 172 return (0); 173 continue; 174 case 'l': 175 if (!_conv(t->tm_hour % 12 ? 176 t->tm_hour % 12: 12, 2, ' ', pt, ptlim)) 177 return (0); 178 continue; 179 case 'M': 180 if (!_conv(t->tm_min, 2, '0', pt, ptlim)) 181 return (0); 182 continue; 183 case 'm': 184 if (!_conv(t->tm_mon + 1, 2, '0', pt, ptlim)) 185 return (0); 186 continue; 187 case 'n': 188 if (!_add("\n", pt, ptlim)) 189 return (0); 190 continue; 191 case 'p': 192 if (!_add(_CurrentTimeLocale->am_pm[t->tm_hour 193 >= 12], pt, ptlim)) 194 return (0); 195 continue; 196 case 'R': 197 if (!_fmt("%H:%M", t, pt, ptlim)) 198 return (0); 199 continue; 200 case 'r': 201 if (!_fmt(_CurrentTimeLocale->t_fmt_ampm, t, pt, 202 ptlim)) 203 return (0); 204 continue; 205 case 'S': 206 if (!_conv(t->tm_sec, 2, '0', pt, ptlim)) 207 return (0); 208 continue; 209 case 's': 210 if (!_secs(t, pt, ptlim)) 211 return (0); 212 continue; 213 case 'T': 214 if (!_fmt("%H:%M:%S", t, pt, ptlim)) 215 return (0); 216 continue; 217 case 't': 218 if (!_add("\t", pt, ptlim)) 219 return (0); 220 continue; 221 case 'U': 222 if (!_conv(SUN_WEEK(t), 2, '0', pt, ptlim)) 223 return (0); 224 continue; 225 case 'u': 226 if (!_conv(t->tm_wday ? t->tm_wday : 7, 1, '0', 227 pt, ptlim)) 228 return (0); 229 continue; 230 case 'V': /* ISO 8601 week number */ 231 case 'G': /* ISO 8601 year (four digits) */ 232 case 'g': /* ISO 8601 year (two digits) */ 233 /* 234 ** From Arnold Robbins' strftime version 3.0: "the week number of the 235 ** year (the first Monday as the first day of week 1) as a decimal number 236 ** (01-53)." 237 ** (ado, 1993-05-24) 238 ** 239 ** From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn: 240 ** "Week 01 of a year is per definition the first week which has the 241 ** Thursday in this year, which is equivalent to the week which contains 242 ** the fourth day of January. In other words, the first week of a new year 243 ** is the week which has the majority of its days in the new year. Week 01 244 ** might also contain days from the previous year and the week before week 245 ** 01 of a year is the last week (52 or 53) of the previous year even if 246 ** it contains days from the new year. A week starts with Monday (day 1) 247 ** and ends with Sunday (day 7). For example, the first week of the year 248 ** 1997 lasts from 1996-12-30 to 1997-01-05..." 249 ** (ado, 1996-01-02) 250 */ 251 { 252 int year; 253 int yday; 254 int wday; 255 int w; 256 257 year = t->tm_year + TM_YEAR_BASE; 258 yday = t->tm_yday; 259 wday = t->tm_wday; 260 for ( ; ; ) { 261 int len; 262 int bot; 263 int top; 264 265 len = isleap(year) ? 266 DAYSPERLYEAR : 267 DAYSPERNYEAR; 268 /* 269 ** What yday (-3 ... 3) does 270 ** the ISO year begin on? 271 */ 272 bot = ((yday + 11 - wday) % 273 DAYSPERWEEK) - 3; 274 /* 275 ** What yday does the NEXT 276 ** ISO year begin on? 277 */ 278 top = bot - 279 (len % DAYSPERWEEK); 280 if (top < -3) 281 top += DAYSPERWEEK; 282 top += len; 283 if (yday >= top) { 284 ++year; 285 w = 1; 286 break; 287 } 288 if (yday >= bot) { 289 w = 1 + ((yday - bot) / 290 DAYSPERWEEK); 291 break; 292 } 293 --year; 294 yday += isleap(year) ? 295 DAYSPERLYEAR : 296 DAYSPERNYEAR; 297 } 298 #ifdef XPG4_1994_04_09 299 if ((w == 52 300 && t->tm_mon == TM_JANUARY) 301 || (w == 1 302 && t->tm_mon == TM_DECEMBER)) 303 w = 53; 304 #endif /* defined XPG4_1994_04_09 */ 305 if (*format == 'V') { 306 if (!_conv(w, 2, '0', 307 pt, ptlim)) 308 return (0); 309 } else if (*format == 'g') { 310 if (!_conv(year % 100, 2, '0', 311 pt, ptlim)) 312 return (0); 313 } else if (!_conv(year, 4, '0', 314 pt, ptlim)) 315 return (0); 316 } 317 continue; 318 case 'W': 319 if (!_conv(MON_WEEK(t), 2, '0', pt, ptlim)) 320 return (0); 321 continue; 322 case 'w': 323 if (!_conv(t->tm_wday, 1, '0', pt, ptlim)) 324 return (0); 325 continue; 326 case 'x': 327 if (!_fmt(_CurrentTimeLocale->d_fmt, t, pt, 328 ptlim)) 329 return (0); 330 continue; 331 case 'X': 332 if (!_fmt(_CurrentTimeLocale->t_fmt, t, pt, 333 ptlim)) 334 return (0); 335 continue; 336 case 'y': 337 if (!_conv((t->tm_year + TM_YEAR_BASE) % 100, 338 2, '0', pt, ptlim)) 339 return (0); 340 continue; 341 case 'Y': 342 if (!_conv((t->tm_year + TM_YEAR_BASE), 4, '0', 343 pt, ptlim)) 344 return (0); 345 continue; 346 case 'Z': 347 if (tzname[t->tm_isdst ? 1 : 0] && 348 !_add(tzname[t->tm_isdst ? 1 : 0], pt, 349 ptlim)) 350 return (0); 351 continue; 352 case '%': 353 /* 354 * X311J/88-090 (4.12.3.5): if conversion char is 355 * undefined, behavior is undefined. Print out the 356 * character itself as printf(3) does. 357 */ 358 default: 359 break; 360 } 361 } 362 if (*pt == ptlim) 363 return (0); 364 *(*pt)++ = *format; 365 } 366 return (ptlim - *pt); 367 } 368 369 static int 370 _secs(t, pt, ptlim) 371 const struct tm *t; 372 char **pt; 373 const char * const ptlim; 374 { 375 char buf[15]; 376 time_t s; 377 char *p; 378 struct tm tmp; 379 380 buf[sizeof (buf) - 1] = '\0'; 381 /* Make a copy, mktime(3) modifies the tm struct. */ 382 tmp = *t; 383 s = mktime(&tmp); 384 for (p = buf + sizeof(buf) - 2; s > 0 && p > buf; s /= 10) 385 *p-- = (char)(s % 10 + '0'); 386 return (_add(++p, pt, ptlim)); 387 } 388 389 static int 390 _conv(n, digits, pad, pt, ptlim) 391 int n, digits; 392 int pad; 393 char **pt; 394 const char * const ptlim; 395 { 396 char buf[10]; 397 char *p; 398 399 buf[sizeof (buf) - 1] = '\0'; 400 p = buf + sizeof(buf) - 2; 401 do { 402 *p-- = n % 10 + '0'; 403 n /= 10; 404 --digits; 405 } while (n > 0 && p > buf); 406 while (p > buf && digits-- > 0) 407 *p-- = pad; 408 return (_add(++p, pt, ptlim)); 409 } 410 411 static int 412 _add(str, pt, ptlim) 413 const char *str; 414 char **pt; 415 const char * const ptlim; 416 { 417 418 for (;; ++(*pt)) { 419 if (*pt == ptlim) 420 return (0); 421 if ((**pt = *str++) == '\0') 422 return (1); 423 } 424 } 425
Indexes created Thu Sep 25 14:09:45 GMT 2025