strptime.c revision 1.16
1/* $OpenBSD: strptime.c,v 1.16 2014/02/13 23:16:03 millert Exp $ */ 2/* $NetBSD: strptime.c,v 1.12 1998/01/20 21:39:40 mycroft Exp $ */ 3 4/*- 5 * Copyright (c) 1997, 1998, 2005, 2008 The NetBSD Foundation, Inc. 6 * All rights reserved. 7 * 8 * This code was contributed to The NetBSD Foundation by Klaus Klein. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32#include <sys/localedef.h> 33#include <ctype.h> 34#include <locale.h> 35#include <string.h> 36#include <time.h> 37#include <tzfile.h> 38 39#define _ctloc(x) (_CurrentTimeLocale->x) 40 41/* 42 * We do not implement alternate representations. However, we always 43 * check whether a given modifier is allowed for a certain conversion. 44 */ 45#define _ALT_E 0x01 46#define _ALT_O 0x02 47#define _LEGAL_ALT(x) { if (alt_format & ~(x)) return (0); } 48 49/* 50 * We keep track of some of the fields we set in order to compute missing ones. 51 */ 52#define FIELD_TM_MON (1 << 0) 53#define FIELD_TM_MDAY (1 << 1) 54#define FIELD_TM_WDAY (1 << 2) 55#define FIELD_TM_YDAY (1 << 3) 56#define FIELD_TM_YEAR (1 << 4) 57 58static char gmt[] = { "GMT" }; 59#ifdef TM_ZONE 60static char utc[] = { "UTC" }; 61#endif 62/* RFC-822/RFC-2822 */ 63static const char * const nast[5] = { 64 "EST", "CST", "MST", "PST", "\0\0\0" 65}; 66static const char * const nadt[5] = { 67 "EDT", "CDT", "MDT", "PDT", "\0\0\0" 68}; 69 70static const int mon_lengths[2][MONSPERYEAR] = { 71 { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }, 72 { 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 } 73}; 74 75static int _conv_num(const unsigned char **, int *, int, int); 76static int leaps_thru_end_of(const int y); 77static char *_strptime(const char *, const char *, struct tm *, int); 78static const u_char *_find_string(const u_char *, int *, const char * const *, 79 const char * const *, int); 80 81 82char * 83strptime(const char *buf, const char *fmt, struct tm *tm) 84{ 85 return(_strptime(buf, fmt, tm, 1)); 86} 87 88static char * 89_strptime(const char *buf, const char *fmt, struct tm *tm, int initialize) 90{ 91 unsigned char c; 92 const unsigned char *bp, *ep; 93 size_t len; 94 int alt_format, i, offs; 95 int neg = 0; 96 static int century, relyear, fields; 97 98 if (initialize) { 99 century = TM_YEAR_BASE; 100 relyear = -1; 101 fields = 0; 102 } 103 104 bp = (unsigned char *)buf; 105 while ((c = *fmt) != '\0') { 106 /* Clear `alternate' modifier prior to new conversion. */ 107 alt_format = 0; 108 109 /* Eat up white-space. */ 110 if (isspace(c)) { 111 while (isspace(*bp)) 112 bp++; 113 114 fmt++; 115 continue; 116 } 117 118 if ((c = *fmt++) != '%') 119 goto literal; 120 121 122again: switch (c = *fmt++) { 123 case '%': /* "%%" is converted to "%". */ 124literal: 125 if (c != *bp++) 126 return (NULL); 127 128 break; 129 130 /* 131 * "Alternative" modifiers. Just set the appropriate flag 132 * and start over again. 133 */ 134 case 'E': /* "%E?" alternative conversion modifier. */ 135 _LEGAL_ALT(0); 136 alt_format |= _ALT_E; 137 goto again; 138 139 case 'O': /* "%O?" alternative conversion modifier. */ 140 _LEGAL_ALT(0); 141 alt_format |= _ALT_O; 142 goto again; 143 144 /* 145 * "Complex" conversion rules, implemented through recursion. 146 */ 147 case 'c': /* Date and time, using the locale's format. */ 148 _LEGAL_ALT(_ALT_E); 149 if (!(bp = _strptime(bp, _ctloc(d_t_fmt), tm, 0))) 150 return (NULL); 151 break; 152 153 case 'D': /* The date as "%m/%d/%y". */ 154 _LEGAL_ALT(0); 155 if (!(bp = _strptime(bp, "%m/%d/%y", tm, 0))) 156 return (NULL); 157 break; 158 159 case 'F': /* The date as "%Y-%m-%d". */ 160 _LEGAL_ALT(0); 161 if (!(bp = _strptime(bp, "%Y-%m-%d", tm, 0))) 162 return (NULL); 163 continue; 164 165 case 'R': /* The time as "%H:%M". */ 166 _LEGAL_ALT(0); 167 if (!(bp = _strptime(bp, "%H:%M", tm, 0))) 168 return (NULL); 169 break; 170 171 case 'r': /* The time as "%I:%M:%S %p". */ 172 _LEGAL_ALT(0); 173 if (!(bp = _strptime(bp, "%I:%M:%S %p", tm, 0))) 174 return (NULL); 175 break; 176 177 case 'T': /* The time as "%H:%M:%S". */ 178 _LEGAL_ALT(0); 179 if (!(bp = _strptime(bp, "%H:%M:%S", tm, 0))) 180 return (NULL); 181 break; 182 183 case 'X': /* The time, using the locale's format. */ 184 _LEGAL_ALT(_ALT_E); 185 if (!(bp = _strptime(bp, _ctloc(t_fmt), tm, 0))) 186 return (NULL); 187 break; 188 189 case 'x': /* The date, using the locale's format. */ 190 _LEGAL_ALT(_ALT_E); 191 if (!(bp = _strptime(bp, _ctloc(d_fmt), tm, 0))) 192 return (NULL); 193 break; 194 195 /* 196 * "Elementary" conversion rules. 197 */ 198 case 'A': /* The day of week, using the locale's form. */ 199 case 'a': 200 _LEGAL_ALT(0); 201 for (i = 0; i < 7; i++) { 202 /* Full name. */ 203 len = strlen(_ctloc(day[i])); 204 if (strncasecmp(_ctloc(day[i]), bp, len) == 0) 205 break; 206 207 /* Abbreviated name. */ 208 len = strlen(_ctloc(abday[i])); 209 if (strncasecmp(_ctloc(abday[i]), bp, len) == 0) 210 break; 211 } 212 213 /* Nothing matched. */ 214 if (i == 7) 215 return (NULL); 216 217 tm->tm_wday = i; 218 bp += len; 219 fields |= FIELD_TM_WDAY; 220 break; 221 222 case 'B': /* The month, using the locale's form. */ 223 case 'b': 224 case 'h': 225 _LEGAL_ALT(0); 226 for (i = 0; i < 12; i++) { 227 /* Full name. */ 228 len = strlen(_ctloc(mon[i])); 229 if (strncasecmp(_ctloc(mon[i]), bp, len) == 0) 230 break; 231 232 /* Abbreviated name. */ 233 len = strlen(_ctloc(abmon[i])); 234 if (strncasecmp(_ctloc(abmon[i]), bp, len) == 0) 235 break; 236 } 237 238 /* Nothing matched. */ 239 if (i == 12) 240 return (NULL); 241 242 tm->tm_mon = i; 243 bp += len; 244 fields |= FIELD_TM_MON; 245 break; 246 247 case 'C': /* The century number. */ 248 _LEGAL_ALT(_ALT_E); 249 if (!(_conv_num(&bp, &i, 0, 99))) 250 return (NULL); 251 252 century = i * 100; 253 break; 254 255 case 'd': /* The day of month. */ 256 case 'e': 257 _LEGAL_ALT(_ALT_O); 258 if (!(_conv_num(&bp, &tm->tm_mday, 1, 31))) 259 return (NULL); 260 fields |= FIELD_TM_MDAY; 261 break; 262 263 case 'k': /* The hour (24-hour clock representation). */ 264 _LEGAL_ALT(0); 265 /* FALLTHROUGH */ 266 case 'H': 267 _LEGAL_ALT(_ALT_O); 268 if (!(_conv_num(&bp, &tm->tm_hour, 0, 23))) 269 return (NULL); 270 break; 271 272 case 'l': /* The hour (12-hour clock representation). */ 273 _LEGAL_ALT(0); 274 /* FALLTHROUGH */ 275 case 'I': 276 _LEGAL_ALT(_ALT_O); 277 if (!(_conv_num(&bp, &tm->tm_hour, 1, 12))) 278 return (NULL); 279 break; 280 281 case 'j': /* The day of year. */ 282 _LEGAL_ALT(0); 283 if (!(_conv_num(&bp, &tm->tm_yday, 1, 366))) 284 return (NULL); 285 tm->tm_yday--; 286 fields |= FIELD_TM_YDAY; 287 break; 288 289 case 'M': /* The minute. */ 290 _LEGAL_ALT(_ALT_O); 291 if (!(_conv_num(&bp, &tm->tm_min, 0, 59))) 292 return (NULL); 293 break; 294 295 case 'm': /* The month. */ 296 _LEGAL_ALT(_ALT_O); 297 if (!(_conv_num(&bp, &tm->tm_mon, 1, 12))) 298 return (NULL); 299 tm->tm_mon--; 300 fields |= FIELD_TM_MON; 301 break; 302 303 case 'p': /* The locale's equivalent of AM/PM. */ 304 _LEGAL_ALT(0); 305 /* AM? */ 306 len = strlen(_ctloc(am_pm[0])); 307 if (strncasecmp(_ctloc(am_pm[0]), bp, len) == 0) { 308 if (tm->tm_hour > 12) /* i.e., 13:00 AM ?! */ 309 return (NULL); 310 else if (tm->tm_hour == 12) 311 tm->tm_hour = 0; 312 313 bp += len; 314 break; 315 } 316 /* PM? */ 317 len = strlen(_ctloc(am_pm[1])); 318 if (strncasecmp(_ctloc(am_pm[1]), bp, len) == 0) { 319 if (tm->tm_hour > 12) /* i.e., 13:00 PM ?! */ 320 return (NULL); 321 else if (tm->tm_hour < 12) 322 tm->tm_hour += 12; 323 324 bp += len; 325 break; 326 } 327 328 /* Nothing matched. */ 329 return (NULL); 330 331 case 'S': /* The seconds. */ 332 _LEGAL_ALT(_ALT_O); 333 if (!(_conv_num(&bp, &tm->tm_sec, 0, 61))) 334 return (NULL); 335 break; 336 337 case 'U': /* The week of year, beginning on sunday. */ 338 case 'W': /* The week of year, beginning on monday. */ 339 _LEGAL_ALT(_ALT_O); 340 /* 341 * XXX This is bogus, as we can not assume any valid 342 * information present in the tm structure at this 343 * point to calculate a real value, so just check the 344 * range for now. 345 */ 346 if (!(_conv_num(&bp, &i, 0, 53))) 347 return (NULL); 348 break; 349 350 case 'w': /* The day of week, beginning on sunday. */ 351 _LEGAL_ALT(_ALT_O); 352 if (!(_conv_num(&bp, &tm->tm_wday, 0, 6))) 353 return (NULL); 354 fields |= FIELD_TM_WDAY; 355 break; 356 357 case 'u': /* The day of week, monday = 1. */ 358 _LEGAL_ALT(_ALT_O); 359 if (!(_conv_num(&bp, &i, 1, 7))) 360 return (NULL); 361 tm->tm_wday = i % 7; 362 fields |= FIELD_TM_WDAY; 363 continue; 364 365 case 'g': /* The year corresponding to the ISO week 366 * number but without the century. 367 */ 368 if (!(_conv_num(&bp, &i, 0, 99))) 369 return (NULL); 370 continue; 371 372 case 'G': /* The year corresponding to the ISO week 373 * number with century. 374 */ 375 do 376 bp++; 377 while (isdigit(*bp)); 378 continue; 379 380 case 'V': /* The ISO 8601:1988 week number as decimal */ 381 if (!(_conv_num(&bp, &i, 0, 53))) 382 return (NULL); 383 continue; 384 385 case 'Y': /* The year. */ 386 _LEGAL_ALT(_ALT_E); 387 if (!(_conv_num(&bp, &i, 0, 9999))) 388 return (NULL); 389 390 relyear = -1; 391 tm->tm_year = i - TM_YEAR_BASE; 392 fields |= FIELD_TM_YEAR; 393 break; 394 395 case 'y': /* The year within the century (2 digits). */ 396 _LEGAL_ALT(_ALT_E | _ALT_O); 397 if (!(_conv_num(&bp, &relyear, 0, 99))) 398 return (NULL); 399 break; 400 401 case 'Z': 402 tzset(); 403 if (strncmp((const char *)bp, gmt, 3) == 0) { 404 tm->tm_isdst = 0; 405#ifdef TM_GMTOFF 406 tm->TM_GMTOFF = 0; 407#endif 408#ifdef TM_ZONE 409 tm->TM_ZONE = gmt; 410#endif 411 bp += 3; 412 } else { 413 ep = _find_string(bp, &i, 414 (const char * const *)tzname, 415 NULL, 2); 416 if (ep != NULL) { 417 tm->tm_isdst = i; 418#ifdef TM_GMTOFF 419 tm->TM_GMTOFF = -(timezone); 420#endif 421#ifdef TM_ZONE 422 tm->TM_ZONE = tzname[i]; 423#endif 424 } 425 bp = ep; 426 } 427 continue; 428 429 case 'z': 430 /* 431 * We recognize all ISO 8601 formats: 432 * Z = Zulu time/UTC 433 * [+-]hhmm 434 * [+-]hh:mm 435 * [+-]hh 436 * We recognize all RFC-822/RFC-2822 formats: 437 * UT|GMT 438 * North American : UTC offsets 439 * E[DS]T = Eastern : -4 | -5 440 * C[DS]T = Central : -5 | -6 441 * M[DS]T = Mountain: -6 | -7 442 * P[DS]T = Pacific : -7 | -8 443 * Military 444 * [A-IL-M] = -1 ... -9 (J not used) 445 * [N-Y] = +1 ... +12 446 */ 447 while (isspace(*bp)) 448 bp++; 449 450 switch (*bp++) { 451 case 'G': 452 if (*bp++ != 'M') 453 return NULL; 454 /*FALLTHROUGH*/ 455 case 'U': 456 if (*bp++ != 'T') 457 return NULL; 458 /*FALLTHROUGH*/ 459 case 'Z': 460 tm->tm_isdst = 0; 461#ifdef TM_GMTOFF 462 tm->TM_GMTOFF = 0; 463#endif 464#ifdef TM_ZONE 465 tm->TM_ZONE = utc; 466#endif 467 continue; 468 case '+': 469 neg = 0; 470 break; 471 case '-': 472 neg = 1; 473 break; 474 default: 475 --bp; 476 ep = _find_string(bp, &i, nast, NULL, 4); 477 if (ep != NULL) { 478#ifdef TM_GMTOFF 479 tm->TM_GMTOFF = -5 - i; 480#endif 481#ifdef TM_ZONE 482 tm->TM_ZONE = __UNCONST(nast[i]); 483#endif 484 bp = ep; 485 continue; 486 } 487 ep = _find_string(bp, &i, nadt, NULL, 4); 488 if (ep != NULL) { 489 tm->tm_isdst = 1; 490#ifdef TM_GMTOFF 491 tm->TM_GMTOFF = -4 - i; 492#endif 493#ifdef TM_ZONE 494 tm->TM_ZONE = __UNCONST(nadt[i]); 495#endif 496 bp = ep; 497 continue; 498 } 499 500 if ((*bp >= 'A' && *bp <= 'I') || 501 (*bp >= 'L' && *bp <= 'Y')) { 502#ifdef TM_GMTOFF 503 /* Argh! No 'J'! */ 504 if (*bp >= 'A' && *bp <= 'I') 505 tm->TM_GMTOFF = 506 ('A' - 1) - (int)*bp; 507 else if (*bp >= 'L' && *bp <= 'M') 508 tm->TM_GMTOFF = 'A' - (int)*bp; 509 else if (*bp >= 'N' && *bp <= 'Y') 510 tm->TM_GMTOFF = (int)*bp - 'M'; 511#endif 512#ifdef TM_ZONE 513 tm->TM_ZONE = NULL; /* XXX */ 514#endif 515 bp++; 516 continue; 517 } 518 return NULL; 519 } 520 offs = 0; 521 for (i = 0; i < 4; ) { 522 if (isdigit(*bp)) { 523 offs = offs * 10 + (*bp++ - '0'); 524 i++; 525 continue; 526 } 527 if (i == 2 && *bp == ':') { 528 bp++; 529 continue; 530 } 531 break; 532 } 533 switch (i) { 534 case 2: 535 offs *= 100; 536 break; 537 case 4: 538 i = offs % 100; 539 if (i >= 60) 540 return NULL; 541 /* Convert minutes into decimal */ 542 offs = (offs / 100) * 100 + (i * 50) / 30; 543 break; 544 default: 545 return NULL; 546 } 547 if (neg) 548 offs = -offs; 549 tm->tm_isdst = 0; /* XXX */ 550#ifdef TM_GMTOFF 551 tm->TM_GMTOFF = offs; 552#endif 553#ifdef TM_ZONE 554 tm->TM_ZONE = NULL; /* XXX */ 555#endif 556 continue; 557 558 /* 559 * Miscellaneous conversions. 560 */ 561 case 'n': /* Any kind of white-space. */ 562 case 't': 563 _LEGAL_ALT(0); 564 while (isspace(*bp)) 565 bp++; 566 break; 567 568 569 default: /* Unknown/unsupported conversion. */ 570 return (NULL); 571 } 572 573 574 } 575 576 /* 577 * We need to evaluate the two digit year spec (%y) 578 * last as we can get a century spec (%C) at any time. 579 */ 580 if (relyear != -1) { 581 if (century == TM_YEAR_BASE) { 582 if (relyear <= 68) 583 tm->tm_year = relyear + 2000 - TM_YEAR_BASE; 584 else 585 tm->tm_year = relyear + 1900 - TM_YEAR_BASE; 586 } else { 587 tm->tm_year = relyear + century - TM_YEAR_BASE; 588 } 589 fields |= FIELD_TM_YEAR; 590 } 591 592 /* Compute some missing values when possible. */ 593 if (fields & FIELD_TM_YEAR) { 594 const int year = tm->tm_year + TM_YEAR_BASE; 595 const int *mon_lens = mon_lengths[isleap(year)]; 596 if (!(fields & FIELD_TM_YDAY) && 597 (fields & FIELD_TM_MON) && (fields & FIELD_TM_MDAY)) { 598 tm->tm_yday = tm->tm_mday - 1; 599 for (i = 0; i < tm->tm_mon; i++) 600 tm->tm_yday += mon_lens[i]; 601 fields |= FIELD_TM_YDAY; 602 } 603 if (fields & FIELD_TM_YDAY) { 604 int days = tm->tm_yday; 605 if (!(fields & FIELD_TM_WDAY)) { 606 tm->tm_wday = EPOCH_WDAY + 607 ((year - EPOCH_YEAR) % DAYSPERWEEK) * 608 (DAYSPERNYEAR % DAYSPERWEEK) + 609 leaps_thru_end_of(year - 1) - 610 leaps_thru_end_of(EPOCH_YEAR - 1) + 611 tm->tm_yday; 612 tm->tm_wday %= DAYSPERWEEK; 613 if (tm->tm_wday < 0) 614 tm->tm_wday += DAYSPERWEEK; 615 } 616 if (!(fields & FIELD_TM_MON)) { 617 tm->tm_mon = 0; 618 while (tm->tm_mon < MONSPERYEAR && days >= mon_lens[tm->tm_mon]) 619 days -= mon_lens[tm->tm_mon++]; 620 } 621 if (!(fields & FIELD_TM_MDAY)) 622 tm->tm_mday = days + 1; 623 } 624 } 625 626 return ((char *)bp); 627} 628 629 630static int 631_conv_num(const unsigned char **buf, int *dest, int llim, int ulim) 632{ 633 int result = 0; 634 int rulim = ulim; 635 636 if (**buf < '0' || **buf > '9') 637 return (0); 638 639 /* we use rulim to break out of the loop when we run out of digits */ 640 do { 641 result *= 10; 642 result += *(*buf)++ - '0'; 643 rulim /= 10; 644 } while ((result * 10 <= ulim) && rulim && **buf >= '0' && **buf <= '9'); 645 646 if (result < llim || result > ulim) 647 return (0); 648 649 *dest = result; 650 return (1); 651} 652 653static const u_char * 654_find_string(const u_char *bp, int *tgt, const char * const *n1, 655 const char * const *n2, int c) 656{ 657 int i; 658 unsigned int len; 659 660 /* check full name - then abbreviated ones */ 661 for (; n1 != NULL; n1 = n2, n2 = NULL) { 662 for (i = 0; i < c; i++, n1++) { 663 len = strlen(*n1); 664 if (strncasecmp(*n1, (const char *)bp, len) == 0) { 665 *tgt = i; 666 return bp + len; 667 } 668 } 669 } 670 671 /* Nothing matched */ 672 return NULL; 673} 674 675static int 676leaps_thru_end_of(const int y) 677{ 678 return (y >= 0) ? (y / 4 - y / 100 + y / 400) : 679 -(leaps_thru_end_of(-(y + 1)) + 1); 680} 681