missing/strftime.c

   1 /*
   2  * strftime.c
   3  *
   4  * Public-domain implementation of ANSI C library routine.
   5  *
   6  * It's written in old-style C for maximal portability.
   7  * However, since I'm used to prototypes, I've included them too.
   8  *
   9  * If you want stuff in the System V ascftime routine, add the SYSV_EXT define.
  10  * For extensions from SunOS, add SUNOS_EXT.
  11  * For stuff needed to implement the P1003.2 date command, add POSIX2_DATE.
  12  * For VMS dates, add VMS_EXT.
  13  * For a an RFC822 time format, add MAILHEADER_EXT.
  14  * For ISO week years, add ISO_DATE_EXT.
  15  * For complete POSIX semantics, add POSIX_SEMANTICS.
  16  *
  17  * The code for %c, %x, and %X now follows the 1003.2 specification for
  18  * the POSIX locale.
  19  * This version ignores LOCALE information.
  20  * It also doesn't worry about multi-byte characters.
  21  * So there.
  22  *
  23  * This file is also shipped with GAWK (GNU Awk), gawk specific bits of
  24  * code are included if GAWK is defined.
  25  *
  26  * Arnold Robbins
  27  * January, February, March, 1991
  28  * Updated March, April 1992
  29  * Updated April, 1993
  30  * Updated February, 1994
  31  * Updated May, 1994
  32  * Updated January, 1995
  33  * Updated September, 1995
  34  * Updated January, 1996
  35  *
  36  * Fixes from ado@elsie.nci.nih.gov
  37  * February 1991, May 1992
  38  * Fixes from Tor Lillqvist tml@tik.vtt.fi
  39  * May, 1993
  40  * Further fixes from ado@elsie.nci.nih.gov
  41  * February 1994
  42  * %z code from chip@chinacat.unicom.com
  43  * Applied September 1995
  44  * %V code fixed (again) and %G, %g added,
  45  * January 1996
  46  */
  47
  48 #include "ruby/config.h"
  49
  50 #ifndef GAWK
  51 #include <stdio.h>
  52 #include <ctype.h>
  53 #include <string.h>
  54 #include <time.h>
  55 #endif
  56 #if defined(TM_IN_SYS_TIME) || !defined(GAWK) && !defined(_WIN32_WCE)
  57 #include <sys/types.h>
  58 #include <sys/time.h>
  59 #endif
  60
  61 /* defaults: season to taste */
  62 #define SYSV_EXT        1       /* stuff in System V ascftime routine */
  63 #define SUNOS_EXT       1       /* stuff in SunOS strftime routine */
  64 #define POSIX2_DATE     1       /* stuff in Posix 1003.2 date command */
  65 #define VMS_EXT         1       /* include %v for VMS date format */
  66 #define MAILHEADER_EXT  1       /* add %z for HHMM format */
  67 #define ISO_DATE_EXT    1       /* %G and %g for year of ISO week */
  68 #ifndef GAWK
  69 #define POSIX_SEMANTICS 1       /* call tzset() if TZ changes */
  70 #endif
  71
  72 #if defined(ISO_DATE_EXT)
  73 #if ! defined(POSIX2_DATE)
  74 #define POSIX2_DATE     1
  75 #endif
  76 #endif
  77
  78 #if defined(POSIX2_DATE)
  79 #if ! defined(SYSV_EXT)
  80 #define SYSV_EXT        1
  81 #endif
  82 #if ! defined(SUNOS_EXT)
  83 #define SUNOS_EXT       1
  84 #endif
  85 #endif
  86
  87 #if defined(POSIX2_DATE)
  88 #define adddecl(stuff)  stuff
  89 #else
  90 #define adddecl(stuff)
  91 #endif
  92
  93 #undef strchr   /* avoid AIX weirdness */
  94
  95 #ifndef __STDC__
  96 #define const   /**/
  97 extern void tzset();
  98 static int weeknumber();
  99 adddecl(static int iso8601wknum();)
 100 #else
 101 extern void tzset(void);
 102 static int weeknumber(const struct tm *timeptr, int firstweekday);
 103 adddecl(static int iso8601wknum(const struct tm *timeptr);)
 104 #endif
 105
 106 #ifdef STDC_HEADERS
 107 #include <stdlib.h>
 108 #include <string.h>
 109 #else
 110 extern void *malloc();
 111 extern void *realloc();
 112 extern char *getenv();
 113 extern char *strchr();
 114 #endif
 115
 116 #define range(low, item, hi)    max(low, min(item, hi))
 117
 118 #ifdef __CYGWIN__
 119 #define DLL_IMPORT __declspec(dllimport)
 120 #endif
 121 #ifdef __WIN32__
 122 #define DLL_IMPORT __declspec(dllimport)
 123 #endif
 124 #if !defined(OS2) && !defined(MSDOS) && defined(HAVE_TZNAME)
 125 extern DLL_IMPORT char *tzname[2];
 126 #ifdef HAVE_DAYLIGHT
 127 extern DLL_IMPORT int daylight;
 128 #endif
 129 #ifdef HAVE_VAR_TIMEZONE
 130 extern DLL_IMPORT TYPEOF_VAR_TIMEZONE timezone;
 131 #endif
 132 #ifdef HAVE_VAR_ALTZONE
 133 extern DLL_IMPORT TYPEOF_VAR_ALTZONE altzone;
 134 #endif
 135 #endif
 136
 137 #undef min      /* just in case */
 138
 139 /* min --- return minimum of two numbers */
 140
 141 #ifndef __STDC__
 142 static inline int
 143 min(a, b)
 144 int a, b;
 145 #else
 146 static inline int
 147 min(int a, int b)
 148 #endif
 149 {
 150         return (a < b ? a : b);
 151 }
 152
 153 #undef max      /* also, just in case */
 154
 155 /* max --- return maximum of two numbers */
 156
 157 #ifndef __STDC__
 158 static inline int
 159 max(a, b)
 160 int a, b;
 161 #else
 162 static inline int
 163 max(int a, int b)
 164 #endif
 165 {
 166         return (a > b ? a : b);
 167 }
 168
 169 /* strftime --- produce formatted time */
 170
 171 #ifndef __STDC__
 172 size_t
 173 strftime(s, maxsize, format, timeptr)
 174 char *s;
 175 size_t maxsize;
 176 const char *format;
 177 const struct tm *timeptr;
 178 #else
 179 size_t
 180 strftime(char *s, size_t maxsize, const char *format, const struct tm *timeptr)
 181 #endif
 182 {
 183         char *endp = s + maxsize;
 184         char *start = s;
 185         auto char tbuf[100];
 186         long off;
 187         int i, w;
 188         long y;
 189         static short first = 1;
 190 #ifdef POSIX_SEMANTICS
 191         static char *savetz = NULL;
 192         static int savetzlen = 0;
 193         char *tz;
 194 #endif /* POSIX_SEMANTICS */
 195 #ifndef HAVE_TM_ZONE
 196 #ifndef HAVE_TM_NAME
 197         struct timeval tv;
 198         struct timezone zone;
 199 #endif /* HAVE_TM_NAME */
 200 #endif /* HAVE_TM_ZONE */
 201
 202         /* various tables, useful in North America */
 203         static const char *days_a[] = {
 204                 "Sun", "Mon", "Tue", "Wed",
 205                 "Thu", "Fri", "Sat",
 206         };
 207         static const char *days_l[] = {
 208                 "Sunday", "Monday", "Tuesday", "Wednesday",
 209                 "Thursday", "Friday", "Saturday",
 210         };
 211         static const char *months_a[] = {
 212                 "Jan", "Feb", "Mar", "Apr", "May", "Jun",
 213                 "Jul", "Aug", "Sep", "Oct", "Nov", "Dec",
 214         };
 215         static const char *months_l[] = {
 216                 "January", "February", "March", "April",
 217                 "May", "June", "July", "August", "September",
 218                 "October", "November", "December",
 219         };
 220         static const char *ampm[] = { "AM", "PM", };
 221
 222         if (s == NULL || format == NULL || timeptr == NULL || maxsize == 0)
 223                 return 0;
 224
 225         /* quick check if we even need to bother */
 226         if (strchr(format, '%') == NULL && strlen(format) + 1 >= maxsize)
 227                 return 0;
 228
 229 #ifndef POSIX_SEMANTICS
 230         if (first) {
 231                 tzset();
 232                 first = 0;
 233         }
 234 #else   /* POSIX_SEMANTICS */
 235         tz = getenv("TZ");
 236         if (first) {
 237                 if (tz != NULL) {
 238                         int tzlen = strlen(tz);
 239
 240                         savetz = (char *) malloc(tzlen + 1);
 241                         if (savetz != NULL) {
 242                                 savetzlen = tzlen + 1;
 243                                 strcpy(savetz, tz);
 244                         }
 245                 }
 246                 tzset();
 247                 first = 0;
 248         }
 249         /* if we have a saved TZ, and it is different, recapture and reset */
 250         if (tz && savetz && (tz[0] != savetz[0] || strcmp(tz, savetz) != 0)) {
 251                 i = strlen(tz) + 1;
 252                 if (i > savetzlen) {
 253                         savetz = (char *) realloc(savetz, i);
 254                         if (savetz) {
 255                                 savetzlen = i;
 256                                 strcpy(savetz, tz);
 257                         }
 258                 } else
 259                         strcpy(savetz, tz);
 260                 tzset();
 261         }
 262 #endif  /* POSIX_SEMANTICS */
 263
 264         for (; *format && s < endp - 1; format++) {
 265                 tbuf[0] = '\0';
 266                 if (*format != '%') {
 267                         *s++ = *format;
 268                         continue;
 269                 }
 270         again:
 271                 switch (*++format) {
 272                 case '\0':
 273                         *s++ = '%';
 274                         goto out;
 275
 276                 case '%':
 277                         *s++ = '%';
 278                         continue;
 279
 280                 case 'a':       /* abbreviated weekday name */
 281                         if (timeptr->tm_wday < 0 || timeptr->tm_wday > 6)
 282                                 strcpy(tbuf, "?");
 283                         else
 284                                 strcpy(tbuf, days_a[timeptr->tm_wday]);
 285                         break;
 286
 287                 case 'A':       /* full weekday name */
 288                         if (timeptr->tm_wday < 0 || timeptr->tm_wday > 6)
 289                                 strcpy(tbuf, "?");
 290                         else
 291                                 strcpy(tbuf, days_l[timeptr->tm_wday]);
 292                         break;
 293
 294 #ifdef SYSV_EXT
 295                 case 'h':       /* abbreviated month name */
 296 #endif
 297                 case 'b':       /* abbreviated month name */
 298                         if (timeptr->tm_mon < 0 || timeptr->tm_mon > 11)
 299                                 strcpy(tbuf, "?");
 300                         else
 301                                 strcpy(tbuf, months_a[timeptr->tm_mon]);
 302                         break;
 303
 304                 case 'B':       /* full month name */
 305                         if (timeptr->tm_mon < 0 || timeptr->tm_mon > 11)
 306                                 strcpy(tbuf, "?");
 307                         else
 308                                 strcpy(tbuf, months_l[timeptr->tm_mon]);
 309                         break;
 310
 311                 case 'c':       /* appropriate date and time representation */
 312                         strftime(tbuf, sizeof tbuf, "%a %b %e %H:%M:%S %Y", timeptr);
 313                         break;
 314
 315                 case 'd':       /* day of the month, 01 - 31 */
 316                         i = range(1, timeptr->tm_mday, 31);
 317                         sprintf(tbuf, "%02d", i);
 318                         break;
 319
 320                 case 'H':       /* hour, 24-hour clock, 00 - 23 */
 321                         i = range(0, timeptr->tm_hour, 23);
 322                         sprintf(tbuf, "%02d", i);
 323                         break;
 324
 325                 case 'I':       /* hour, 12-hour clock, 01 - 12 */
 326                         i = range(0, timeptr->tm_hour, 23);
 327                         if (i == 0)
 328                                 i = 12;
 329                         else if (i > 12)
 330                                 i -= 12;
 331                         sprintf(tbuf, "%02d", i);
 332                         break;
 333
 334                 case 'j':       /* day of the year, 001 - 366 */
 335                         sprintf(tbuf, "%03d", timeptr->tm_yday + 1);
 336                         break;
 337
 338                 case 'm':       /* month, 01 - 12 */
 339                         i = range(0, timeptr->tm_mon, 11);
 340                         sprintf(tbuf, "%02d", i + 1);
 341                         break;
 342
 343                 case 'M':       /* minute, 00 - 59 */
 344                         i = range(0, timeptr->tm_min, 59);
 345                         sprintf(tbuf, "%02d", i);
 346                         break;
 347
 348                 case 'p':       /* am or pm based on 12-hour clock */
 349                         i = range(0, timeptr->tm_hour, 23);
 350                         if (i < 12)
 351                                 strcpy(tbuf, ampm[0]);
 352                         else
 353                                 strcpy(tbuf, ampm[1]);
 354                         break;
 355
 356                 case 'S':       /* second, 00 - 60 */
 357                         i = range(0, timeptr->tm_sec, 60);
 358                         sprintf(tbuf, "%02d", i);
 359                         break;
 360
 361                 case 'U':       /* week of year, Sunday is first day of week */
 362                         sprintf(tbuf, "%02d", weeknumber(timeptr, 0));
 363                         break;
 364
 365                 case 'w':       /* weekday, Sunday == 0, 0 - 6 */
 366                         i = range(0, timeptr->tm_wday, 6);
 367                         sprintf(tbuf, "%d", i);
 368                         break;
 369
 370                 case 'W':       /* week of year, Monday is first day of week */
 371                         sprintf(tbuf, "%02d", weeknumber(timeptr, 1));
 372                         break;
 373
 374                 case 'x':       /* appropriate date representation */
 375                         strftime(tbuf, sizeof tbuf, "%m/%d/%y", timeptr);
 376                         break;
 377
 378                 case 'X':       /* appropriate time representation */
 379                         strftime(tbuf, sizeof tbuf, "%H:%M:%S", timeptr);
 380                         break;
 381
 382                 case 'y':       /* year without a century, 00 - 99 */
 383                         i = timeptr->tm_year % 100;
 384                         sprintf(tbuf, "%02d", i);
 385                         break;
 386
 387                 case 'Y':       /* year with century */
 388                         sprintf(tbuf, "%ld", 1900L + timeptr->tm_year);
 389                         break;
 390
 391 #ifdef MAILHEADER_EXT
 392                 /*
 393                  * From: Chip Rosenthal <chip@chinacat.unicom.com>
 394                  * Date: Sun, 19 Mar 1995 00:33:29 -0600 (CST)
 395                  *
 396                  * Warning: the %z [code] is implemented by inspecting the
 397                  * timezone name conditional compile settings, and
 398                  * inferring a method to get timezone offsets. I've tried
 399                  * this code on a couple of machines, but I don't doubt
 400                  * there is some system out there that won't like it.
 401                  * Maybe the easiest thing to do would be to bracket this
 402                  * with an #ifdef that can turn it off. The %z feature
 403                  * would be an admittedly obscure one that most folks can
 404                  * live without, but it would be a great help to those of
 405                  * us that muck around with various message processors.
 406                  */
 407                 case 'z':       /* time zone offset east of GMT e.g. -0600 */
 408 #ifdef HAVE_TM_NAME
 409                         /*
 410                          * Systems with tm_name probably have tm_tzadj as
 411                          * secs west of GMT.  Convert to mins east of GMT.
 412                          */
 413                         off = -timeptr->tm_tzadj / 60;
 414 #else /* !HAVE_TM_NAME */
 415 #ifdef HAVE_TM_ZONE
 416                         /*
 417                          * Systems with tm_zone probably have tm_gmtoff as
 418                          * secs east of GMT.  Convert to mins east of GMT.
 419                          */
 420                         off = timeptr->tm_gmtoff / 60;
 421 #else /* !HAVE_TM_ZONE */
 422 #ifdef HAVE_GETTIMEOFDAY
 423                         gettimeofday(&tv, &zone);
 424                         off = -zone.tz_minuteswest;
 425 #else
 426 #if HAVE_VAR_TIMEZONE
 427 #if HAVE_VAR_ALTZONE
 428                         off = -(daylight ? timezone : altzone) / 60;
 429 #else
 430                         off = -timezone / 60;
 431 #endif
 432 #endif
 433 #endif
 434 #endif /* !HAVE_TM_ZONE */
 435 #endif /* !HAVE_TM_NAME */
 436                         if (off < 0) {
 437                                 tbuf[0] = '-';
 438                                 off = -off;
 439                         } else {
 440                                 tbuf[0] = '+';
 441                         }
 442                         sprintf(tbuf+1, "%02u%02u", (unsigned)off/60, (unsigned)off%60);
 443                         break;
 444 #endif /* MAILHEADER_EXT */
 445
 446                 case 'Z':       /* time zone name or abbrevation */
 447 #ifdef HAVE_TZNAME
 448                         i = (daylight && timeptr->tm_isdst > 0); /* 0 or 1 */
 449                         strcpy(tbuf, tzname[i]);
 450 #else
 451 #ifdef HAVE_TM_ZONE
 452                         strcpy(tbuf, timeptr->tm_zone);
 453 #else
 454 #ifdef HAVE_TM_NAME
 455                         strcpy(tbuf, timeptr->tm_name);
 456 #else
 457 #ifdef HAVE_TIMEZONE
 458                         gettimeofday(& tv, & zone);
 459 #ifdef TIMEZONE_VOID
 460                         strcpy(tbuf, timezone());
 461 #else
 462                         strcpy(tbuf, timezone(zone.tz_minuteswest,
 463                                                 timeptr->tm_isdst > 0));
 464 #endif /* TIMEZONE_VOID */
 465 #endif /* HAVE_TIMEZONE */
 466 #endif /* HAVE_TM_NAME */
 467 #endif /* HAVE_TM_ZONE */
 468 #endif /* HAVE_TZNAME */
 469                         break;
 470
 471 #ifdef SYSV_EXT
 472                 case 'n':       /* same as \n */
 473                         tbuf[0] = '\n';
 474                         tbuf[1] = '\0';
 475                         break;
 476
 477                 case 't':       /* same as \t */
 478                         tbuf[0] = '\t';
 479                         tbuf[1] = '\0';
 480                         break;
 481
 482                 case 'D':       /* date as %m/%d/%y */
 483                         strftime(tbuf, sizeof tbuf, "%m/%d/%y", timeptr);
 484                         break;
 485
 486                 case 'e':       /* day of month, blank padded */
 487                         sprintf(tbuf, "%2d", range(1, timeptr->tm_mday, 31));
 488                         break;
 489
 490                 case 'r':       /* time as %I:%M:%S %p */
 491                         strftime(tbuf, sizeof tbuf, "%I:%M:%S %p", timeptr);
 492                         break;
 493
 494                 case 'R':       /* time as %H:%M */
 495                         strftime(tbuf, sizeof tbuf, "%H:%M", timeptr);
 496                         break;
 497
 498                 case 'T':       /* time as %H:%M:%S */
 499                         strftime(tbuf, sizeof tbuf, "%H:%M:%S", timeptr);
 500                         break;
 501 #endif
 502
 503 #ifdef SUNOS_EXT
 504                 case 'k':       /* hour, 24-hour clock, blank pad */
 505                         sprintf(tbuf, "%2d", range(0, timeptr->tm_hour, 23));
 506                         break;
 507
 508                 case 'l':       /* hour, 12-hour clock, 1 - 12, blank pad */
 509                         i = range(0, timeptr->tm_hour, 23);
 510                         if (i == 0)
 511                                 i = 12;
 512                         else if (i > 12)
 513                                 i -= 12;
 514                         sprintf(tbuf, "%2d", i);
 515                         break;
 516 #endif
 517
 518
 519 #ifdef VMS_EXT
 520                 case 'v':       /* date as dd-bbb-YYYY */
 521                         sprintf(tbuf, "%2d-%3.3s-%4ld",
 522                                 range(1, timeptr->tm_mday, 31),
 523                                 months_a[range(0, timeptr->tm_mon, 11)],
 524                                 timeptr->tm_year + 1900L);
 525                         for (i = 3; i < 6; i++)
 526                                 if (islower(tbuf[i]))
 527                                         tbuf[i] = toupper(tbuf[i]);
 528                         break;
 529 #endif
 530
 531
 532 #ifdef POSIX2_DATE
 533                 case 'C':
 534                         sprintf(tbuf, "%02ld", (timeptr->tm_year + 1900L) / 100);
 535                         break;
 536
 537
 538                 case 'E':
 539                 case 'O':
 540                         /* POSIX locale extensions, ignored for now */
 541                         goto again;
 542
 543                 case 'V':       /* week of year according ISO 8601 */
 544                         sprintf(tbuf, "%02d", iso8601wknum(timeptr));
 545                         break;
 546
 547                 case 'u':
 548                 /* ISO 8601: Weekday as a decimal number [1 (Monday) - 7] */
 549                         sprintf(tbuf, "%d", timeptr->tm_wday == 0 ? 7 :
 550                                         timeptr->tm_wday);
 551                         break;
 552 #endif  /* POSIX2_DATE */
 553
 554 #ifdef ISO_DATE_EXT
 555                 case 'G':
 556                 case 'g':
 557                         /*
 558                          * Year of ISO week.
 559                          *
 560                          * If it's December but the ISO week number is one,
 561                          * that week is in next year.
 562                          * If it's January but the ISO week number is 52 or
 563                          * 53, that week is in last year.
 564                          * Otherwise, it's this year.
 565                          */
 566                         w = iso8601wknum(timeptr);
 567                         if (timeptr->tm_mon == 11 && w == 1)
 568                                 y = 1900L + timeptr->tm_year + 1;
 569                         else if (timeptr->tm_mon == 0 && w >= 52)
 570                                 y = 1900L + timeptr->tm_year - 1;
 571                         else
 572                                 y = 1900L + timeptr->tm_year;
 573
 574                         if (*format == 'G')
 575                                 sprintf(tbuf, "%ld", y);
 576                         else
 577                                 sprintf(tbuf, "%02ld", y % 100);
 578                         break;
 579 #endif /* ISO_DATE_EXT */
 580                 default:
 581                         tbuf[0] = '%';
 582                         tbuf[1] = *format;
 583                         tbuf[2] = '\0';
 584                         break;
 585                 }
 586                 i = strlen(tbuf);
 587                 if (i) {
 588                         if (s + i < endp - 1) {
 589                                 strcpy(s, tbuf);
 590                                 s += i;
 591                         } else
 592                                 return 0;
 593                 }
 594         }
 595 out:
 596         if (s < endp && *format == '\0') {
 597                 *s = '\0';
 598                 return (s - start);
 599         } else
 600                 return 0;
 601 }
 602
 603 /* isleap --- is a year a leap year? */
 604
 605 #ifndef __STDC__
 606 static int
 607 isleap(year)
 608 long year;
 609 #else
 610 static int
 611 isleap(long year)
 612 #endif
 613 {
 614         return ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0);
 615 }
 616
 617
 618 #ifdef POSIX2_DATE
 619 /* iso8601wknum --- compute week number according to ISO 8601 */
 620
 621 #ifndef __STDC__
 622 static int
 623 iso8601wknum(timeptr)
 624 const struct tm *timeptr;
 625 #else
 626 static int
 627 iso8601wknum(const struct tm *timeptr)
 628 #endif
 629 {
 630         /*
 631          * From 1003.2:
 632          *      If the week (Monday to Sunday) containing January 1
 633          *      has four or more days in the new year, then it is week 1;
 634          *      otherwise it is the highest numbered week of the previous
 635          *      year (52 or 53), and the next week is week 1.
 636          *
 637          * ADR: This means if Jan 1 was Monday through Thursday,
 638          *      it was week 1, otherwise week 52 or 53.
 639          *
 640          * XPG4 erroneously included POSIX.2 rationale text in the
 641          * main body of the standard. Thus it requires week 53.
 642          */
 643
 644         int weeknum, jan1day;
 645
 646         /* get week number, Monday as first day of the week */
 647         weeknum = weeknumber(timeptr, 1);
 648
 649         /*
 650          * With thanks and tip of the hatlo to tml@tik.vtt.fi
 651          *
 652          * What day of the week does January 1 fall on?
 653          * We know that
 654          *      (timeptr->tm_yday - jan1.tm_yday) MOD 7 ==
 655          *              (timeptr->tm_wday - jan1.tm_wday) MOD 7
 656          * and that
 657          *      jan1.tm_yday == 0
 658          * and that
 659          *      timeptr->tm_wday MOD 7 == timeptr->tm_wday
 660          * from which it follows that. . .
 661          */
 662         jan1day = timeptr->tm_wday - (timeptr->tm_yday % 7);
 663         if (jan1day < 0)
 664                 jan1day += 7;
 665
 666         /*
 667          * If Jan 1 was a Monday through Thursday, it was in
 668          * week 1.  Otherwise it was last year's highest week, which is
 669          * this year's week 0.
 670          *
 671          * What does that mean?
 672          * If Jan 1 was Monday, the week number is exactly right, it can
 673          *      never be 0.
 674          * If it was Tuesday through Thursday, the weeknumber is one
 675          *      less than it should be, so we add one.
 676          * Otherwise, Friday, Saturday or Sunday, the week number is
 677          * OK, but if it is 0, it needs to be 52 or 53.
 678          */
 679         switch (jan1day) {
 680         case 1:         /* Monday */
 681                 break;
 682         case 2:         /* Tuesday */
 683         case 3:         /* Wednesday */
 684         case 4:         /* Thursday */
 685                 weeknum++;
 686                 break;
 687         case 5:         /* Friday */
 688         case 6:         /* Saturday */
 689         case 0:         /* Sunday */
 690                 if (weeknum == 0) {
 691 #ifdef USE_BROKEN_XPG4
 692                         /* XPG4 (as of March 1994) says 53 unconditionally */
 693                         weeknum = 53;
 694 #else
 695                         /* get week number of last week of last year */
 696                         struct tm dec31ly;      /* 12/31 last year */
 697                         dec31ly = *timeptr;
 698                         dec31ly.tm_year--;
 699                         dec31ly.tm_mon = 11;
 700                         dec31ly.tm_mday = 31;
 701                         dec31ly.tm_wday = (jan1day == 0) ? 6 : jan1day - 1;
 702                         dec31ly.tm_yday = 364 + isleap(dec31ly.tm_year + 1900L);
 703                         weeknum = iso8601wknum(& dec31ly);
 704 #endif
 705                 }
 706                 break;
 707         }
 708
 709         if (timeptr->tm_mon == 11) {
 710                 /*
 711                  * The last week of the year
 712                  * can be in week 1 of next year.
 713                  * Sigh.
 714                  *
 715                  * This can only happen if
 716                  *      M   T  W
 717                  *      29  30 31
 718                  *      30  31
 719                  *      31
 720                  */
 721                 int wday, mday;
 722
 723                 wday = timeptr->tm_wday;
 724                 mday = timeptr->tm_mday;
 725                 if (   (wday == 1 && (mday >= 29 && mday <= 31))
 726                     || (wday == 2 && (mday == 30 || mday == 31))
 727                     || (wday == 3 &&  mday == 31))
 728                         weeknum = 1;
 729         }
 730
 731         return weeknum;
 732 }
 733 #endif
 734
 735 /* weeknumber --- figure how many weeks into the year */
 736
 737 /* With thanks and tip of the hatlo to ado@elsie.nci.nih.gov */
 738
 739 #ifndef __STDC__
 740 static int
 741 weeknumber(timeptr, firstweekday)
 742 const struct tm *timeptr;
 743 int firstweekday;
 744 #else
 745 static int
 746 weeknumber(const struct tm *timeptr, int firstweekday)
 747 #endif
 748 {
 749         int wday = timeptr->tm_wday;
 750         int ret;
 751
 752         if (firstweekday == 1) {
 753                 if (wday == 0)  /* sunday */
 754                         wday = 6;
 755                 else
 756                         wday--;
 757         }
 758         ret = ((timeptr->tm_yday + 7 - wday) / 7);
 759         if (ret < 0)
 760                 ret = 0;
 761         return ret;
 762 }
 763
 764 #if 0
 765 /* ADR --- I'm loathe to mess with ado's code ... */
 766
 767 Date:         Wed, 24 Apr 91 20:54:08 MDT
 768 From: Michal Jaegermann <audfax!emory!vm.ucs.UAlberta.CA!NTOMCZAK>
 769 To: arnold@audiofax.com
 770
 771 Hi Arnold,
 772 in a process of fixing of strftime() in libraries on Atari ST I grabbed
 773 some pieces of code from your own strftime.  When doing that it came
 774 to mind that your weeknumber() function compiles a little bit nicer
 775 in the following form:
 776 /*
 777  * firstweekday is 0 if starting in Sunday, non-zero if in Monday
 778  */
 779 {
 780     return (timeptr->tm_yday - timeptr->tm_wday +
 781             (firstweekday ? (timeptr->tm_wday ? 8 : 1) : 7)) / 7;
 782 }
 783 How nicer it depends on a compiler, of course, but always a tiny bit.
 784
 785    Cheers,
 786    Michal
 787    ntomczak@vm.ucs.ualberta.ca
 788 #endif
 789
 790 #ifdef  TEST_STRFTIME
 791
 792 /*
 793  * NAME:
 794  *      tst
 795  *
 796  * SYNOPSIS:
 797  *      tst
 798  *
 799  * DESCRIPTION:
 800  *      "tst" is a test driver for the function "strftime".
 801  *
 802  * OPTIONS:
 803  *      None.
 804  *
 805  * AUTHOR:
 806  *      Karl Vogel
 807  *      Control Data Systems, Inc.
 808  *      vogelke@c-17igp.wpafb.af.mil
 809  *
 810  * BUGS:
 811  *      None noticed yet.
 812  *
 813  * COMPILE:
 814  *      cc -o tst -DTEST_STRFTIME strftime.c
 815  */
 816
 817 /* ADR: I reformatted this to my liking, and deleted some unneeded code. */
 818
 819 #ifndef NULL
 820 #include        <stdio.h>
 821 #endif
 822 #include        <sys/time.h>
 823 #include        <string.h>
 824
 825 #define         MAXTIME         132
 826
 827 /*
 828  * Array of time formats.
 829  */
 830
 831 static char *array[] =
 832 {
 833         "(%%A)      full weekday name, var length (Sunday..Saturday)  %A",
 834         "(%%B)       full month name, var length (January..December)  %B",
 835         "(%%C)                                               Century  %C",
 836         "(%%D)                                       date (%%m/%%d/%%y)  %D",
 837         "(%%E)                           Locale extensions (ignored)  %E",
 838         "(%%H)                          hour (24-hour clock, 00..23)  %H",
 839         "(%%I)                          hour (12-hour clock, 01..12)  %I",
 840         "(%%M)                                       minute (00..59)  %M",
 841         "(%%O)                           Locale extensions (ignored)  %O",
 842         "(%%R)                                 time, 24-hour (%%H:%%M)  %R",
 843         "(%%S)                                       second (00..60)  %S",
 844         "(%%T)                              time, 24-hour (%%H:%%M:%%S)  %T",
 845         "(%%U)    week of year, Sunday as first day of week (00..53)  %U",
 846         "(%%V)                    week of year according to ISO 8601  %V",
 847         "(%%W)    week of year, Monday as first day of week (00..53)  %W",
 848         "(%%X)     appropriate locale time representation (%H:%M:%S)  %X",
 849         "(%%Y)                           year with century (1970...)  %Y",
 850         "(%%Z) timezone (EDT), or blank if timezone not determinable  %Z",
 851         "(%%a)          locale's abbreviated weekday name (Sun..Sat)  %a",
 852         "(%%b)            locale's abbreviated month name (Jan..Dec)  %b",
 853         "(%%c)           full date (Sat Nov  4 12:02:33 1989)%n%t%t%t  %c",
 854         "(%%d)                             day of the month (01..31)  %d",
 855         "(%%e)               day of the month, blank-padded ( 1..31)  %e",
 856         "(%%h)                                should be same as (%%b)  %h",
 857         "(%%j)                            day of the year (001..366)  %j",
 858         "(%%k)               hour, 24-hour clock, blank pad ( 0..23)  %k",
 859         "(%%l)               hour, 12-hour clock, blank pad ( 0..12)  %l",
 860         "(%%m)                                        month (01..12)  %m",
 861         "(%%p)              locale's AM or PM based on 12-hour clock  %p",
 862         "(%%r)                   time, 12-hour (same as %%I:%%M:%%S %%p)  %r",
 863         "(%%u) ISO 8601: Weekday as decimal number [1 (Monday) - 7]   %u",
 864         "(%%v)                                VMS date (dd-bbb-YYYY)  %v",
 865         "(%%w)                       day of week (0..6, Sunday == 0)  %w",
 866         "(%%x)                appropriate locale date representation  %x",
 867         "(%%y)                      last two digits of year (00..99)  %y",
 868         "(%%z)      timezone offset east of GMT as HHMM (e.g. -0500)  %z",
 869         (char *) NULL
 870 };
 871
 872 /* main routine. */
 873
 874 int
 875 main(argc, argv)
 876 int argc;
 877 char **argv;
 878 {
 879         long time();
 880
 881         char *next;
 882         char string[MAXTIME];
 883
 884         int k;
 885         int length;
 886
 887         struct tm *tm;
 888
 889         long clock;
 890
 891         /* Call the function. */
 892
 893         clock = time((long *) 0);
 894         tm = localtime(&clock);
 895
 896         for (k = 0; next = array[k]; k++) {
 897                 length = strftime(string, MAXTIME, next, tm);
 898                 printf("%s\n", string);
 899         }
 900
 901         exit(0);
 902 }
 903 #endif  /* TEST_STRFTIME */