strftime.c revision 51186
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 51186 1999-09-11 21:35:21Z dt $"; 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 alternative; 79 for ( ; *format; ++format) { 80 if (*format == '%') { 81 alternative = 0; 82label: 83 switch (*++format) { 84 case '\0': 85 --format; 86 break; 87 case 'A': 88 pt = _add((t->tm_wday < 0 || t->tm_wday > 6) ? 89 "?" : Locale->weekday[t->tm_wday], 90 pt, ptlim); 91 continue; 92 case 'a': 93 pt = _add((t->tm_wday < 0 || t->tm_wday > 6) ? 94 "?" : Locale->wday[t->tm_wday], 95 pt, ptlim); 96 continue; 97 case 'B': 98 pt = _add((t->tm_mon < 0 || t->tm_mon > 11) ? 99 "?" : (alternative ? Locale->alt_month : 100 Locale->month)[t->tm_mon], 101 pt, ptlim); 102 continue; 103 case 'b': 104 case 'h': 105 pt = _add((t->tm_mon < 0 || t->tm_mon > 11) ? 106 "?" : Locale->mon[t->tm_mon], 107 pt, ptlim); 108 continue; 109 case 'C': 110 /* 111 ** %C used to do a... 112 ** _fmt("%a %b %e %X %Y", t); 113 ** ...whereas now POSIX 1003.2 calls for 114 ** something completely different. 115 ** (ado, 5/24/93) 116 */ 117 pt = _conv((t->tm_year + TM_YEAR_BASE) / 100, 118 "%02d", pt, ptlim); 119 continue; 120 case 'c': 121 pt = _fmt(Locale->c_fmt, t, pt, ptlim); 122 continue; 123 case 'D': 124 pt = _fmt("%m/%d/%y", t, pt, ptlim); 125 continue; 126 case 'd': 127 pt = _conv(t->tm_mday, "%02d", pt, ptlim); 128 continue; 129 case 'E': 130 case 'O': 131 /* 132 ** POSIX locale extensions, a la 133 ** Arnold Robbins' strftime version 3.0. 134 ** The sequences 135 ** %Ec %EC %Ex %Ey %EY 136 ** %Od %oe %OH %OI %Om %OM 137 ** %OS %Ou %OU %OV %Ow %OW %Oy 138 ** are supposed to provide alternate 139 ** representations. 140 ** (ado, 5/24/93) 141 */ 142 alternative = 1; 143 goto label; 144 case 'e': 145 pt = _conv(t->tm_mday, "%2d", pt, ptlim); 146 continue; 147 case 'H': 148 pt = _conv(t->tm_hour, "%02d", pt, ptlim); 149 continue; 150 case 'I': 151 pt = _conv((t->tm_hour % 12) ? 152 (t->tm_hour % 12) : 12, 153 "%02d", pt, ptlim); 154 continue; 155 case 'j': 156 pt = _conv(t->tm_yday + 1, "%03d", pt, ptlim); 157 continue; 158 case 'k': 159 /* 160 ** This used to be... 161 ** _conv(t->tm_hour % 12 ? 162 ** t->tm_hour % 12 : 12, 2, ' '); 163 ** ...and has been changed to the below to 164 ** match SunOS 4.1.1 and Arnold Robbins' 165 ** strftime version 3.0. That is, "%k" and 166 ** "%l" have been swapped. 167 ** (ado, 5/24/93) 168 */ 169 pt = _conv(t->tm_hour, "%2d", pt, ptlim); 170 continue; 171#ifdef KITCHEN_SINK 172 case 'K': 173 /* 174 ** After all this time, still unclaimed! 175 */ 176 pt = _add("kitchen sink", pt, ptlim); 177 continue; 178#endif /* defined KITCHEN_SINK */ 179 case 'l': 180 /* 181 ** This used to be... 182 ** _conv(t->tm_hour, 2, ' '); 183 ** ...and has been changed to the below to 184 ** match SunOS 4.1.1 and Arnold Robbin's 185 ** strftime version 3.0. That is, "%k" and 186 ** "%l" have been swapped. 187 ** (ado, 5/24/93) 188 */ 189 pt = _conv((t->tm_hour % 12) ? 190 (t->tm_hour % 12) : 12, 191 "%2d", pt, ptlim); 192 continue; 193 case 'M': 194 pt = _conv(t->tm_min, "%02d", pt, ptlim); 195 continue; 196 case 'm': 197 pt = _conv(t->tm_mon + 1, "%02d", pt, ptlim); 198 continue; 199 case 'n': 200 pt = _add("\n", pt, ptlim); 201 continue; 202 case 'p': 203 pt = _add((t->tm_hour >= 12) ? 204 Locale->pm : 205 Locale->am, 206 pt, ptlim); 207 continue; 208 case 'R': 209 pt = _fmt("%H:%M", t, pt, ptlim); 210 continue; 211 case 'r': 212 pt = _fmt("%I:%M:%S %p", t, pt, ptlim); 213 continue; 214 case 'S': 215 pt = _conv(t->tm_sec, "%02d", pt, ptlim); 216 continue; 217 case 's': 218 { 219 struct tm tm; 220 char buf[INT_STRLEN_MAXIMUM( 221 time_t) + 1]; 222 time_t mkt; 223 224 tm = *t; 225 mkt = mktime(&tm); 226 if (TYPE_SIGNED(time_t)) 227 (void) sprintf(buf, "%ld", 228 (long) mkt); 229 else (void) sprintf(buf, "%lu", 230 (unsigned long) mkt); 231 pt = _add(buf, pt, ptlim); 232 } 233 continue; 234 case 'T': 235 pt = _fmt("%H:%M:%S", t, pt, ptlim); 236 continue; 237 case 't': 238 pt = _add("\t", pt, ptlim); 239 continue; 240 case 'U': 241 pt = _conv((t->tm_yday + 7 - t->tm_wday) / 7, 242 "%02d", pt, ptlim); 243 continue; 244 case 'u': 245 /* 246 ** From Arnold Robbins' strftime version 3.0: 247 ** "ISO 8601: Weekday as a decimal number 248 ** [1 (Monday) - 7]" 249 ** (ado, 5/24/93) 250 */ 251 pt = _conv((t->tm_wday == 0) ? 7 : t->tm_wday, 252 "%d", pt, ptlim); 253 continue; 254 case 'V': /* ISO 8601 week number */ 255 case 'G': /* ISO 8601 year (four digits) */ 256 case 'g': /* ISO 8601 year (two digits) */ 257/* 258** From Arnold Robbins' strftime version 3.0: "the week number of the 259** year (the first Monday as the first day of week 1) as a decimal number 260** (01-53)." 261** (ado, 1993-05-24) 262** 263** From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn: 264** "Week 01 of a year is per definition the first week which has the 265** Thursday in this year, which is equivalent to the week which contains 266** the fourth day of January. In other words, the first week of a new year 267** is the week which has the majority of its days in the new year. Week 01 268** might also contain days from the previous year and the week before week 269** 01 of a year is the last week (52 or 53) of the previous year even if 270** it contains days from the new year. A week starts with Monday (day 1) 271** and ends with Sunday (day 7). For example, the first week of the year 272** 1997 lasts from 1996-12-30 to 1997-01-05..." 273** (ado, 1996-01-02) 274*/ 275 { 276 int year; 277 int yday; 278 int wday; 279 int w; 280 281 year = t->tm_year + TM_YEAR_BASE; 282 yday = t->tm_yday; 283 wday = t->tm_wday; 284 for ( ; ; ) { 285 int len; 286 int bot; 287 int top; 288 289 len = isleap(year) ? 290 DAYSPERLYEAR : 291 DAYSPERNYEAR; 292 /* 293 ** What yday (-3 ... 3) does 294 ** the ISO year begin on? 295 */ 296 bot = ((yday + 11 - wday) % 297 DAYSPERWEEK) - 3; 298 /* 299 ** What yday does the NEXT 300 ** ISO year begin on? 301 */ 302 top = bot - 303 (len % DAYSPERWEEK); 304 if (top < -3) 305 top += DAYSPERWEEK; 306 top += len; 307 if (yday >= top) { 308 ++year; 309 w = 1; 310 break; 311 } 312 if (yday >= bot) { 313 w = 1 + ((yday - bot) / 314 DAYSPERWEEK); 315 break; 316 } 317 --year; 318 yday += isleap(year) ? 319 DAYSPERLYEAR : 320 DAYSPERNYEAR; 321 } 322#ifdef XPG4_1994_04_09 323 if ((w == 52 324 && t->tm_mon == TM_JANUARY) 325 || (w == 1 326 && t->tm_mon == TM_DECEMBER)) 327 w = 53; 328#endif /* defined XPG4_1994_04_09 */ 329 if (*format == 'V') 330 pt = _conv(w, "%02d", 331 pt, ptlim); 332 else if (*format == 'g') { 333 pt = _conv(year % 100, "%02d", 334 pt, ptlim); 335 } else pt = _conv(year, "%04d", 336 pt, ptlim); 337 } 338 continue; 339 case 'v': 340 /* 341 ** From Arnold Robbins' strftime version 3.0: 342 ** "date as dd-bbb-YYYY" 343 ** (ado, 5/24/93) 344 */ 345 pt = _fmt("%e-%b-%Y", t, pt, ptlim); 346 continue; 347 case 'W': 348 pt = _conv((t->tm_yday + 7 - 349 (t->tm_wday ? 350 (t->tm_wday - 1) : 6)) / 7, 351 "%02d", pt, ptlim); 352 continue; 353 case 'w': 354 pt = _conv(t->tm_wday, "%d", pt, ptlim); 355 continue; 356 case 'X': 357 pt = _fmt(Locale->X_fmt, t, pt, ptlim); 358 continue; 359 case 'x': 360 pt = _fmt(Locale->x_fmt, t, pt, ptlim); 361 continue; 362 case 'y': 363 pt = _conv((t->tm_year + TM_YEAR_BASE) % 100, 364 "%02d", pt, ptlim); 365 continue; 366 case 'Y': 367 pt = _conv(t->tm_year + TM_YEAR_BASE, "%04d", 368 pt, ptlim); 369 continue; 370 case 'Z': 371 if (t->tm_zone != NULL) 372 pt = _add(t->tm_zone, pt, ptlim); 373 else 374 if (t->tm_isdst == 0 || t->tm_isdst == 1) { 375 pt = _add(tzname[t->tm_isdst], 376 pt, ptlim); 377 } else pt = _add("?", pt, ptlim); 378 continue; 379 case '+': 380 pt = _fmt(Locale->date_fmt, t, pt, ptlim); 381 continue; 382 case '%': 383 /* 384 * X311J/88-090 (4.12.3.5): if conversion char is 385 * undefined, behavior is undefined. Print out the 386 * character itself as printf(3) also does. 387 */ 388 default: 389 break; 390 } 391 } 392 if (pt == ptlim) 393 break; 394 *pt++ = *format; 395 } 396 return pt; 397} 398 399static char * 400_conv(n, format, pt, ptlim) 401 const int n; 402 const char *const format; 403 char *const pt; 404 const char *const ptlim; 405{ 406 char buf[INT_STRLEN_MAXIMUM(int) + 1]; 407 408 (void) sprintf(buf, format, n); 409 return _add(buf, pt, ptlim); 410} 411 412static char * 413_add(str, pt, ptlim) 414 const char *str; 415 char *pt; 416 const char *const ptlim; 417{ 418 while (pt < ptlim && (*pt = *str++) != '\0') 419 ++pt; 420 return pt; 421} 422