strftime.c revision 53940
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 53940 1999-11-30 07:33:37Z ache $"; 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 Ealternative++; 133 goto label; 134 case 'O': 135 /* 136 ** POSIX locale extensions, a la 137 ** Arnold Robbins' strftime version 3.0. 138 ** The sequences 139 ** %Ec %EC %Ex %Ey %EY 140 ** %Od %oe %OH %OI %Om %OM 141 ** %OS %Ou %OU %OV %Ow %OW %Oy 142 ** are supposed to provide alternate 143 ** representations. 144 ** (ado, 5/24/93) 145 */ 146 Oalternative++; 147 goto label; 148 case 'e': 149 pt = _conv(t->tm_mday, "%2d", pt, ptlim); 150 continue; 151 case 'H': 152 pt = _conv(t->tm_hour, "%02d", pt, ptlim); 153 continue; 154 case 'I': 155 pt = _conv((t->tm_hour % 12) ? 156 (t->tm_hour % 12) : 12, 157 "%02d", pt, ptlim); 158 continue; 159 case 'j': 160 pt = _conv(t->tm_yday + 1, "%03d", pt, ptlim); 161 continue; 162 case 'k': 163 /* 164 ** This used to be... 165 ** _conv(t->tm_hour % 12 ? 166 ** t->tm_hour % 12 : 12, 2, ' '); 167 ** ...and has been changed to the below to 168 ** match SunOS 4.1.1 and Arnold Robbins' 169 ** strftime version 3.0. That is, "%k" and 170 ** "%l" have been swapped. 171 ** (ado, 5/24/93) 172 */ 173 pt = _conv(t->tm_hour, "%2d", pt, ptlim); 174 continue; 175#ifdef KITCHEN_SINK 176 case 'K': 177 /* 178 ** After all this time, still unclaimed! 179 */ 180 pt = _add("kitchen sink", pt, ptlim); 181 continue; 182#endif /* defined KITCHEN_SINK */ 183 case 'l': 184 /* 185 ** This used to be... 186 ** _conv(t->tm_hour, 2, ' '); 187 ** ...and has been changed to the below to 188 ** match SunOS 4.1.1 and Arnold Robbin's 189 ** strftime version 3.0. That is, "%k" and 190 ** "%l" have been swapped. 191 ** (ado, 5/24/93) 192 */ 193 pt = _conv((t->tm_hour % 12) ? 194 (t->tm_hour % 12) : 12, 195 "%2d", pt, ptlim); 196 continue; 197 case 'M': 198 pt = _conv(t->tm_min, "%02d", pt, ptlim); 199 continue; 200 case 'm': 201 pt = _conv(t->tm_mon + 1, "%02d", pt, ptlim); 202 continue; 203 case 'n': 204 pt = _add("\n", pt, ptlim); 205 continue; 206 case 'p': 207 pt = _add((t->tm_hour >= 12) ? 208 Locale->pm : 209 Locale->am, 210 pt, ptlim); 211 continue; 212 case 'R': 213 pt = _fmt("%H:%M", t, pt, ptlim); 214 continue; 215 case 'r': 216 pt = _fmt("%I:%M:%S %p", t, pt, ptlim); 217 continue; 218 case 'S': 219 pt = _conv(t->tm_sec, "%02d", pt, ptlim); 220 continue; 221 case 's': 222 { 223 struct tm tm; 224 char buf[INT_STRLEN_MAXIMUM( 225 time_t) + 1]; 226 time_t mkt; 227 228 tm = *t; 229 mkt = mktime(&tm); 230 if (TYPE_SIGNED(time_t)) 231 (void) sprintf(buf, "%ld", 232 (long) mkt); 233 else (void) sprintf(buf, "%lu", 234 (unsigned long) mkt); 235 pt = _add(buf, pt, ptlim); 236 } 237 continue; 238 case 'T': 239 pt = _fmt("%H:%M:%S", t, pt, ptlim); 240 continue; 241 case 't': 242 pt = _add("\t", pt, ptlim); 243 continue; 244 case 'U': 245 pt = _conv((t->tm_yday + 7 - t->tm_wday) / 7, 246 "%02d", pt, ptlim); 247 continue; 248 case 'u': 249 /* 250 ** From Arnold Robbins' strftime version 3.0: 251 ** "ISO 8601: Weekday as a decimal number 252 ** [1 (Monday) - 7]" 253 ** (ado, 5/24/93) 254 */ 255 pt = _conv((t->tm_wday == 0) ? 7 : t->tm_wday, 256 "%d", pt, ptlim); 257 continue; 258 case 'V': /* ISO 8601 week number */ 259 case 'G': /* ISO 8601 year (four digits) */ 260 case 'g': /* ISO 8601 year (two digits) */ 261/* 262** From Arnold Robbins' strftime version 3.0: "the week number of the 263** year (the first Monday as the first day of week 1) as a decimal number 264** (01-53)." 265** (ado, 1993-05-24) 266** 267** From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn: 268** "Week 01 of a year is per definition the first week which has the 269** Thursday in this year, which is equivalent to the week which contains 270** the fourth day of January. In other words, the first week of a new year 271** is the week which has the majority of its days in the new year. Week 01 272** might also contain days from the previous year and the week before week 273** 01 of a year is the last week (52 or 53) of the previous year even if 274** it contains days from the new year. A week starts with Monday (day 1) 275** and ends with Sunday (day 7). For example, the first week of the year 276** 1997 lasts from 1996-12-30 to 1997-01-05..." 277** (ado, 1996-01-02) 278*/ 279 { 280 int year; 281 int yday; 282 int wday; 283 int w; 284 285 year = t->tm_year + TM_YEAR_BASE; 286 yday = t->tm_yday; 287 wday = t->tm_wday; 288 for ( ; ; ) { 289 int len; 290 int bot; 291 int top; 292 293 len = isleap(year) ? 294 DAYSPERLYEAR : 295 DAYSPERNYEAR; 296 /* 297 ** What yday (-3 ... 3) does 298 ** the ISO year begin on? 299 */ 300 bot = ((yday + 11 - wday) % 301 DAYSPERWEEK) - 3; 302 /* 303 ** What yday does the NEXT 304 ** ISO year begin on? 305 */ 306 top = bot - 307 (len % DAYSPERWEEK); 308 if (top < -3) 309 top += DAYSPERWEEK; 310 top += len; 311 if (yday >= top) { 312 ++year; 313 w = 1; 314 break; 315 } 316 if (yday >= bot) { 317 w = 1 + ((yday - bot) / 318 DAYSPERWEEK); 319 break; 320 } 321 --year; 322 yday += isleap(year) ? 323 DAYSPERLYEAR : 324 DAYSPERNYEAR; 325 } 326#ifdef XPG4_1994_04_09 327 if ((w == 52 328 && t->tm_mon == TM_JANUARY) 329 || (w == 1 330 && t->tm_mon == TM_DECEMBER)) 331 w = 53; 332#endif /* defined XPG4_1994_04_09 */ 333 if (*format == 'V') 334 pt = _conv(w, "%02d", 335 pt, ptlim); 336 else if (*format == 'g') { 337 pt = _conv(year % 100, "%02d", 338 pt, ptlim); 339 } else pt = _conv(year, "%04d", 340 pt, ptlim); 341 } 342 continue; 343 case 'v': 344 /* 345 ** From Arnold Robbins' strftime version 3.0: 346 ** "date as dd-bbb-YYYY" 347 ** (ado, 5/24/93) 348 */ 349 pt = _fmt("%e-%b-%Y", t, pt, ptlim); 350 continue; 351 case 'W': 352 pt = _conv((t->tm_yday + 7 - 353 (t->tm_wday ? 354 (t->tm_wday - 1) : 6)) / 7, 355 "%02d", pt, ptlim); 356 continue; 357 case 'w': 358 pt = _conv(t->tm_wday, "%d", pt, ptlim); 359 continue; 360 case 'X': 361 pt = _fmt(Locale->X_fmt, t, pt, ptlim); 362 continue; 363 case 'x': 364 pt = _fmt(Ealternative ? Locale->Ex_fmt : Locale->x_fmt, t, pt, ptlim); 365 continue; 366 case 'y': 367 pt = _conv((t->tm_year + TM_YEAR_BASE) % 100, 368 "%02d", pt, ptlim); 369 continue; 370 case 'Y': 371 pt = _conv(t->tm_year + TM_YEAR_BASE, "%04d", 372 pt, ptlim); 373 continue; 374 case 'Z': 375 if (t->tm_zone != NULL) 376 pt = _add(t->tm_zone, pt, ptlim); 377 else 378 if (t->tm_isdst == 0 || t->tm_isdst == 1) { 379 pt = _add(tzname[t->tm_isdst], 380 pt, ptlim); 381 } else pt = _add("?", pt, ptlim); 382 continue; 383 case '+': 384 pt = _fmt(Locale->date_fmt, t, pt, ptlim); 385 continue; 386 case '%': 387 /* 388 * X311J/88-090 (4.12.3.5): if conversion char is 389 * undefined, behavior is undefined. Print out the 390 * character itself as printf(3) also does. 391 */ 392 default: 393 break; 394 } 395 } 396 if (pt == ptlim) 397 break; 398 *pt++ = *format; 399 } 400 return pt; 401} 402 403static char * 404_conv(n, format, pt, ptlim) 405 const int n; 406 const char *const format; 407 char *const pt; 408 const char *const ptlim; 409{ 410 char buf[INT_STRLEN_MAXIMUM(int) + 1]; 411 412 (void) sprintf(buf, format, n); 413 return _add(buf, pt, ptlim); 414} 415 416static char * 417_add(str, pt, ptlim) 418 const char *str; 419 char *pt; 420 const char *const ptlim; 421{ 422 while (pt < ptlim && (*pt = *str++) != '\0') 423 ++pt; 424 return pt; 425} 426