time.c

   1 /**********************************************************************
   2
   3   time.c -
   4
   5   $Author$
   6   created at: Tue Dec 28 14:31:59 JST 1993
   7
   8   Copyright (C) 1993-2007 Yukihiro Matsumoto
   9
  10 **********************************************************************/
  11
  12 #include "ruby/ruby.h"
  13 #include <sys/types.h>
  14 #include <time.h>
  15 #include <errno.h>
  16 #include "ruby/encoding.h"
  17
  18 #ifdef HAVE_UNISTD_H
  19 #include <unistd.h>
  20 #endif
  21
  22 #include <math.h>
  23
  24 VALUE rb_cTime;
  25 static VALUE time_utc_offset _((VALUE));
  26
  27 static ID id_divmod, id_mul, id_submicro;
  28
  29 struct time_object {
  30     struct timespec ts;
  31     struct tm tm;
  32     int gmt;
  33     int tm_got;
  34 };
  35
  36 #define GetTimeval(obj, tobj) \
  37     Data_Get_Struct(obj, struct time_object, tobj)
  38
  39 static void
  40 time_free(void *tobj)
  41 {
  42     if (tobj) xfree(tobj);
  43 }
  44
  45 static VALUE
  46 time_s_alloc(VALUE klass)
  47 {
  48     VALUE obj;
  49     struct time_object *tobj;
  50
  51     obj = Data_Make_Struct(klass, struct time_object, 0, time_free, tobj);
  52     tobj->tm_got=0;
  53     tobj->ts.tv_sec = 0;
  54     tobj->ts.tv_nsec = 0;
  55
  56     return obj;
  57 }
  58
  59 static void
  60 time_modify(VALUE time)
  61 {
  62     rb_check_frozen(time);
  63     if (!OBJ_UNTRUSTED(time) && rb_safe_level() >= 4)
  64         rb_raise(rb_eSecurityError, "Insecure: can't modify Time");
  65 }
  66
  67 /*
  68  *  Document-method: now
  69  *
  70  *  Synonym for <code>Time.new</code>. Returns a +Time+ object
  71  *  initialized to the current system time.
  72  */
  73
  74 /*
  75  *  call-seq:
  76  *     Time.new -> time
  77  *
  78  *  Returns a <code>Time</code> object initialized to the current system
  79  *  time. <b>Note:</b> The object created will be created using the
  80  *  resolution available on your system clock, and so may include
  81  *  fractional seconds.
  82  *
  83  *     a = Time.new      #=> 2007-11-19 07:50:02 -0600
  84  *     b = Time.new      #=> 2007-11-19 07:50:02 -0600
  85  *     a == b            #=> false
  86  *     "%.6f" % a.to_f   #=> "1195480202.282373"
  87  *     "%.6f" % b.to_f   #=> "1195480202.283415"
  88  *
  89  */
  90
  91 static VALUE
  92 time_init(VALUE time)
  93 {
  94     struct time_object *tobj;
  95
  96     time_modify(time);
  97     GetTimeval(time, tobj);
  98     tobj->tm_got=0;
  99     tobj->ts.tv_sec = 0;
 100     tobj->ts.tv_nsec = 0;
 101 #ifdef HAVE_CLOCK_GETTIME
 102     if (clock_gettime(CLOCK_REALTIME, &tobj->ts) == -1) {
 103         rb_sys_fail("clock_gettime");
 104     }
 105 #else
 106     {
 107         struct timeval tv;
 108         if (gettimeofday(&tv, 0) < 0) {
 109             rb_sys_fail("gettimeofday");
 110         }
 111         tobj->ts.tv_sec = tv.tv_sec;
 112         tobj->ts.tv_nsec = tv.tv_usec * 1000;
 113     }
 114 #endif
 115
 116     return time;
 117 }
 118
 119 #define NDIV(x,y) (-(-((x)+1)/(y))-1)
 120 #define NMOD(x,y) ((y)-(-((x)+1)%(y))-1)
 121
 122 static void
 123 time_overflow_p(time_t *secp, long *nsecp)
 124 {
 125     time_t tmp, sec = *secp;
 126     long nsec = *nsecp;
 127
 128     if (nsec >= 1000000000) {   /* nsec positive overflow */
 129         tmp = sec + nsec / 1000000000;
 130         nsec %= 1000000000;
 131         if (sec > 0 && tmp < 0) {
 132             rb_raise(rb_eRangeError, "out of Time range");
 133         }
 134         sec = tmp;
 135     }
 136     if (nsec < 0) {             /* nsec negative overflow */
 137         tmp = sec + NDIV(nsec,1000000000); /* negative div */
 138         nsec = NMOD(nsec,1000000000);      /* negative mod */
 139         if (sec < 0 && tmp > 0) {
 140             rb_raise(rb_eRangeError, "out of Time range");
 141         }
 142         sec = tmp;
 143     }
 144 #ifndef NEGATIVE_TIME_T
 145     if (sec < 0)
 146         rb_raise(rb_eArgError, "time must be positive");
 147 #endif
 148     *secp = sec;
 149     *nsecp = nsec;
 150 }
 151
 152 static VALUE
 153 time_new_internal(VALUE klass, time_t sec, long nsec)
 154 {
 155     VALUE time = time_s_alloc(klass);
 156     struct time_object *tobj;
 157
 158     GetTimeval(time, tobj);
 159     time_overflow_p(&sec, &nsec);
 160     tobj->ts.tv_sec = sec;
 161     tobj->ts.tv_nsec = nsec;
 162
 163     return time;
 164 }
 165
 166 VALUE
 167 rb_time_new(time_t sec, long usec)
 168 {
 169     return time_new_internal(rb_cTime, sec, usec * 1000);
 170 }
 171
 172 VALUE
 173 rb_time_nano_new(time_t sec, long nsec)
 174 {
 175     return time_new_internal(rb_cTime, sec, nsec);
 176 }
 177
 178 static struct timespec
 179 time_timespec(VALUE num, int interval)
 180 {
 181     struct timespec t;
 182     const char *tstr = interval ? "time interval" : "time";
 183     VALUE i, f, ary;
 184
 185 #ifndef NEGATIVE_TIME_T
 186     interval = 1;
 187 #endif
 188
 189     switch (TYPE(num)) {
 190       case T_FIXNUM:
 191         t.tv_sec = FIX2LONG(num);
 192         if (interval && t.tv_sec < 0)
 193             rb_raise(rb_eArgError, "%s must be positive", tstr);
 194         t.tv_nsec = 0;
 195         break;
 196
 197       case T_FLOAT:
 198         if (interval && RFLOAT_VALUE(num) < 0.0)
 199             rb_raise(rb_eArgError, "%s must be positive", tstr);
 200         else {
 201             double f, d;
 202
 203             d = modf(RFLOAT_VALUE(num), &f);
 204             if (d < 0) {
 205                 d += 1;
 206                 f -= 1;
 207             }
 208             t.tv_sec = (time_t)f;
 209             if (f != t.tv_sec) {
 210                 rb_raise(rb_eRangeError, "%f out of Time range", RFLOAT_VALUE(num));
 211             }
 212             t.tv_nsec = (long)(d*1e9+0.5);
 213         }
 214         break;
 215
 216       case T_BIGNUM:
 217         t.tv_sec = NUM2LONG(num);
 218         if (interval && t.tv_sec < 0)
 219             rb_raise(rb_eArgError, "%s must be positive", tstr);
 220         t.tv_nsec = 0;
 221         break;
 222
 223       default:
 224         if (rb_respond_to(num, id_divmod)) {
 225             ary = rb_check_array_type(rb_funcall(num, id_divmod, 1, INT2FIX(1)));
 226             if (NIL_P(ary)) {
 227                 goto typeerror;
 228             }
 229             i = rb_ary_entry(ary, 0);
 230             f = rb_ary_entry(ary, 1);
 231             t.tv_sec = NUM2LONG(i);
 232             if (interval && t.tv_sec < 0)
 233                 rb_raise(rb_eArgError, "%s must be positive", tstr);
 234             f = rb_funcall(f, id_mul, 1, INT2FIX(1000000000));
 235             t.tv_nsec = NUM2LONG(f);
 236         }
 237         else {
 238 typeerror:
 239             rb_raise(rb_eTypeError, "can't convert %s into %s",
 240                      rb_obj_classname(num), tstr);
 241         }
 242         break;
 243     }
 244     return t;
 245 }
 246
 247 static struct timeval
 248 time_timeval(VALUE num, int interval)
 249 {
 250     struct timespec ts;
 251     struct timeval tv;
 252
 253     ts = time_timespec(num, interval);
 254     tv.tv_sec = ts.tv_sec;
 255     tv.tv_usec = ts.tv_nsec / 1000;
 256
 257     return tv;
 258 }
 259
 260 struct timeval
 261 rb_time_interval(VALUE num)
 262 {
 263     return time_timeval(num, Qtrue);
 264 }
 265
 266 struct timeval
 267 rb_time_timeval(VALUE time)
 268 {
 269     struct time_object *tobj;
 270     struct timeval t;
 271
 272     if (TYPE(time) == T_DATA && RDATA(time)->dfree == time_free) {
 273         GetTimeval(time, tobj);
 274         t.tv_sec = tobj->ts.tv_sec;
 275         t.tv_usec = tobj->ts.tv_nsec / 1000;
 276         return t;
 277     }
 278     return time_timeval(time, Qfalse);
 279 }
 280
 281 struct timespec
 282 rb_time_timespec(VALUE time)
 283 {
 284     struct time_object *tobj;
 285     struct timespec t;
 286
 287     if (TYPE(time) == T_DATA && RDATA(time)->dfree == time_free) {
 288         GetTimeval(time, tobj);
 289         t = tobj->ts;
 290         return t;
 291     }
 292     return time_timespec(time, Qfalse);
 293 }
 294
 295 /*
 296  *  call-seq:
 297  *     Time.at(time) => time
 298  *     Time.at(seconds_with_frac) => time
 299  *     Time.at(seconds, microseconds_with_frac) => time
 300  *
 301  *  Creates a new time object with the value given by <i>time</i>,
 302  *  the given number of <i>seconds_with_frac</i>, or
 303  *  <i>seconds</i> and <i>microseconds_with_frac</i> from the Epoch.
 304  *  <i>seconds_with_frac</i> and <i>microseconds_with_frac</i>
 305  *  can be Integer, Float, Rational, or other Numeric.
 306  *  non-portable feature allows the offset to be negative on some systems.
 307  *
 308  *     Time.at(0)            #=> 1969-12-31 18:00:00 -0600
 309  *     Time.at(Time.at(0))   #=> 1969-12-31 18:00:00 -0600
 310  *     Time.at(946702800)    #=> 1999-12-31 23:00:00 -0600
 311  *     Time.at(-284061600)   #=> 1960-12-31 00:00:00 -0600
 312  *     Time.at(946684800.2).usec #=> 200000
 313  *     Time.at(946684800, 123456.789).nsec #=> 123456789
 314  */
 315
 316 static VALUE
 317 time_s_at(int argc, VALUE *argv, VALUE klass)
 318 {
 319     struct timespec ts;
 320     VALUE time, t;
 321
 322     if (rb_scan_args(argc, argv, "11", &time, &t) == 2) {
 323         ts.tv_sec = NUM2LONG(time);
 324         ts.tv_nsec = NUM2LONG(rb_funcall(t, id_mul, 1, INT2FIX(1000)));
 325     }
 326     else {
 327         ts = rb_time_timespec(time);
 328     }
 329     t = time_new_internal(klass, ts.tv_sec, ts.tv_nsec);
 330     if (TYPE(time) == T_DATA && RDATA(time)->dfree == time_free) {
 331         struct time_object *tobj, *tobj2;
 332
 333         GetTimeval(time, tobj);
 334         GetTimeval(t, tobj2);
 335         tobj2->gmt = tobj->gmt;
 336     }
 337     return t;
 338 }
 339
 340 static const char months[][4] = {
 341     "jan", "feb", "mar", "apr", "may", "jun",
 342     "jul", "aug", "sep", "oct", "nov", "dec",
 343 };
 344
 345 static long
 346 obj2long(VALUE obj)
 347 {
 348     if (TYPE(obj) == T_STRING) {
 349         obj = rb_str_to_inum(obj, 10, Qfalse);
 350     }
 351
 352     return NUM2LONG(obj);
 353 }
 354
 355 static long
 356 obj2nsec(VALUE obj, long *nsec)
 357 {
 358     struct timespec ts;
 359
 360     if (TYPE(obj) == T_STRING) {
 361         obj = rb_str_to_inum(obj, 10, Qfalse);
 362         *nsec = 0;
 363         return NUM2LONG(obj);
 364     }
 365
 366     ts = time_timespec(obj, 1);
 367     *nsec = ts.tv_nsec;
 368     return ts.tv_sec;
 369 }
 370
 371 static long
 372 obj2long1000(VALUE obj)
 373 {
 374     if (TYPE(obj) == T_STRING) {
 375         obj = rb_str_to_inum(obj, 10, Qfalse);
 376         return NUM2LONG(obj) * 1000;
 377     }
 378
 379     return NUM2LONG(rb_funcall(obj, id_mul, 1, INT2FIX(1000)));
 380 }
 381
 382 static void
 383 time_arg(int argc, VALUE *argv, struct tm *tm, long *nsec)
 384 {
 385     VALUE v[8];
 386     int i;
 387     long year;
 388
 389     MEMZERO(tm, struct tm, 1);
 390     *nsec = 0;
 391     if (argc == 10) {
 392         v[0] = argv[5];
 393         v[1] = argv[4];
 394         v[2] = argv[3];
 395         v[3] = argv[2];
 396         v[4] = argv[1];
 397         v[5] = argv[0];
 398         v[6] = Qnil;
 399         tm->tm_isdst = RTEST(argv[8]) ? 1 : 0;
 400     }
 401     else {
 402         rb_scan_args(argc, argv, "17", &v[0],&v[1],&v[2],&v[3],&v[4],&v[5],&v[6],&v[7]);
 403         /* v[6] may be usec or zone (parsedate) */
 404         /* v[7] is wday (parsedate; ignored) */
 405         tm->tm_wday = -1;
 406         tm->tm_isdst = -1;
 407     }
 408
 409     year = obj2long(v[0]);
 410
 411     if (0 <= year && year < 39) {
 412         rb_warning("2 digits year is used: %ld", year);
 413         year += 100;
 414     }
 415     else if (69 <= year && year < 139) {
 416         rb_warning("2 or 3 digits year is used: %ld", year);
 417     }
 418     else {
 419         year -= 1900;
 420     }
 421
 422     tm->tm_year = year;
 423
 424     if (NIL_P(v[1])) {
 425         tm->tm_mon = 0;
 426     }
 427     else {
 428         VALUE s = rb_check_string_type(v[1]);
 429         if (!NIL_P(s)) {
 430             tm->tm_mon = -1;
 431             for (i=0; i<12; i++) {
 432                 if (RSTRING_LEN(s) == 3 &&
 433                     STRCASECMP(months[i], RSTRING_PTR(s)) == 0) {
 434                     tm->tm_mon = i;
 435                     break;
 436                 }
 437             }
 438             if (tm->tm_mon == -1) {
 439                 char c = RSTRING_PTR(s)[0];
 440
 441                 if ('0' <= c && c <= '9') {
 442                     tm->tm_mon = obj2long(s)-1;
 443                 }
 444             }
 445         }
 446         else {
 447             tm->tm_mon = obj2long(v[1])-1;
 448         }
 449     }
 450     if (NIL_P(v[2])) {
 451         tm->tm_mday = 1;
 452     }
 453     else {
 454         tm->tm_mday = obj2long(v[2]);
 455     }
 456     tm->tm_hour = NIL_P(v[3])?0:obj2long(v[3]);
 457     tm->tm_min  = NIL_P(v[4])?0:obj2long(v[4]);
 458     if (!NIL_P(v[6]) && argc == 7) {
 459         tm->tm_sec  = NIL_P(v[5])?0:obj2long(v[5]);
 460         *nsec = obj2long1000(v[6]);
 461     }
 462     else {
 463         /* when argc == 8, v[6] is timezone, but ignored */
 464         tm->tm_sec  = NIL_P(v[5])?0:obj2nsec(v[5], nsec);
 465     }
 466
 467     /* value validation */
 468     if (
 469         tm->tm_year != year ||
 470 #ifndef NEGATIVE_TIME_T
 471         tm->tm_year < 69 ||
 472 #endif
 473            tm->tm_mon  < 0 || tm->tm_mon  > 11
 474         || tm->tm_mday < 1 || tm->tm_mday > 31
 475         || tm->tm_hour < 0 || tm->tm_hour > 24
 476         || (tm->tm_hour == 24 && (tm->tm_min > 0 || tm->tm_sec > 0))
 477         || tm->tm_min  < 0 || tm->tm_min  > 59
 478         || tm->tm_sec  < 0 || tm->tm_sec  > 60)
 479         rb_raise(rb_eArgError, "argument out of range");
 480 }
 481
 482 static VALUE time_gmtime(VALUE);
 483 static VALUE time_localtime(VALUE);
 484 static VALUE time_get_tm(VALUE, int);
 485
 486 static int
 487 leap_year_p(long y)
 488 {
 489     return ((y % 4 == 0) && (y % 100 != 0)) || (y % 400 == 0);
 490 }
 491
 492 #define DIV(n,d) ((n)<0 ? NDIV((n),(d)) : (n)/(d))
 493
 494 static time_t
 495 timegm_noleapsecond(struct tm *tm)
 496 {
 497     static const int common_year_yday_offset[] = {
 498         -1,
 499         -1 + 31,
 500         -1 + 31 + 28,
 501         -1 + 31 + 28 + 31,
 502         -1 + 31 + 28 + 31 + 30,
 503         -1 + 31 + 28 + 31 + 30 + 31,
 504         -1 + 31 + 28 + 31 + 30 + 31 + 30,
 505         -1 + 31 + 28 + 31 + 30 + 31 + 30 + 31,
 506         -1 + 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31,
 507         -1 + 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30,
 508         -1 + 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31,
 509         -1 + 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30
 510           /* 1    2    3    4    5    6    7    8    9    10   11 */
 511     };
 512     static const int leap_year_yday_offset[] = {
 513         -1,
 514         -1 + 31,
 515         -1 + 31 + 29,
 516         -1 + 31 + 29 + 31,
 517         -1 + 31 + 29 + 31 + 30,
 518         -1 + 31 + 29 + 31 + 30 + 31,
 519         -1 + 31 + 29 + 31 + 30 + 31 + 30,
 520         -1 + 31 + 29 + 31 + 30 + 31 + 30 + 31,
 521         -1 + 31 + 29 + 31 + 30 + 31 + 30 + 31 + 31,
 522         -1 + 31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30,
 523         -1 + 31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31,
 524         -1 + 31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30
 525           /* 1    2    3    4    5    6    7    8    9    10   11 */
 526     };
 527
 528     long tm_year = tm->tm_year;
 529     int tm_yday = tm->tm_mday;
 530     if (leap_year_p(tm_year + 1900))
 531         tm_yday += leap_year_yday_offset[tm->tm_mon];
 532     else
 533         tm_yday += common_year_yday_offset[tm->tm_mon];
 534
 535     /*
 536      *  `Seconds Since the Epoch' in SUSv3:
 537      *  tm_sec + tm_min*60 + tm_hour*3600 + tm_yday*86400 +
 538      *  (tm_year-70)*31536000 + ((tm_year-69)/4)*86400 -
 539      *  ((tm_year-1)/100)*86400 + ((tm_year+299)/400)*86400
 540      */
 541     return tm->tm_sec + tm->tm_min*60 + tm->tm_hour*3600 +
 542            (time_t)(tm_yday +
 543                     (tm_year-70)*365 +
 544                     DIV(tm_year-69,4) -
 545                     DIV(tm_year-1,100) +
 546                     DIV(tm_year+299,400))*86400;
 547 }
 548
 549 static int
 550 tmcmp(struct tm *a, struct tm *b)
 551 {
 552     if (a->tm_year != b->tm_year)
 553         return a->tm_year < b->tm_year ? -1 : 1;
 554     else if (a->tm_mon != b->tm_mon)
 555         return a->tm_mon < b->tm_mon ? -1 : 1;
 556     else if (a->tm_mday != b->tm_mday)
 557         return a->tm_mday < b->tm_mday ? -1 : 1;
 558     else if (a->tm_hour != b->tm_hour)
 559         return a->tm_hour < b->tm_hour ? -1 : 1;
 560     else if (a->tm_min != b->tm_min)
 561         return a->tm_min < b->tm_min ? -1 : 1;
 562     else if (a->tm_sec != b->tm_sec)
 563         return a->tm_sec < b->tm_sec ? -1 : 1;
 564     else
 565         return 0;
 566 }
 567
 568 #if SIZEOF_TIME_T == SIZEOF_LONG
 569 typedef unsigned long unsigned_time_t;
 570 #elif SIZEOF_TIME_T == SIZEOF_INT
 571 typedef unsigned int unsigned_time_t;
 572 #elif SIZEOF_TIME_T == SIZEOF_LONG_LONG
 573 typedef unsigned LONG_LONG unsigned_time_t;
 574 #else
 575 # error cannot find integer type which size is same as time_t.
 576 #endif
 577
 578 static time_t
 579 search_time_t(struct tm *tptr, int utc_p)
 580 {
 581     time_t guess, guess_lo, guess_hi;
 582     struct tm *tm, tm_lo, tm_hi;
 583     int d, have_guess;
 584     int find_dst;
 585
 586     find_dst = 0 < tptr->tm_isdst;
 587
 588 #ifdef NEGATIVE_TIME_T
 589     guess_lo = (time_t)~((unsigned_time_t)~(time_t)0 >> 1);
 590 #else
 591     guess_lo = 0;
 592 #endif
 593     guess_hi = ((time_t)-1) < ((time_t)0) ?
 594                (time_t)((unsigned_time_t)~(time_t)0 >> 1) :
 595                ~(time_t)0;
 596
 597     guess = timegm_noleapsecond(tptr);
 598     tm = (utc_p ? gmtime : localtime)(&guess);
 599     if (tm) {
 600         d = tmcmp(tptr, tm);
 601         if (d == 0) return guess;
 602         if (d < 0) {
 603             guess_hi = guess;
 604             guess -= 24 * 60 * 60;
 605         }
 606         else {
 607             guess_lo = guess;
 608             guess += 24 * 60 * 60;
 609         }
 610         if (guess_lo < guess && guess < guess_hi &&
 611             (tm = (utc_p ? gmtime : localtime)(&guess)) != NULL) {
 612             d = tmcmp(tptr, tm);
 613             if (d == 0) return guess;
 614             if (d < 0)
 615                 guess_hi = guess;
 616             else
 617                 guess_lo = guess;
 618         }
 619     }
 620
 621     tm = (utc_p ? gmtime : localtime)(&guess_lo);
 622     if (!tm) goto error;
 623     d = tmcmp(tptr, tm);
 624     if (d < 0) goto out_of_range;
 625     if (d == 0) return guess_lo;
 626     tm_lo = *tm;
 627
 628     tm = (utc_p ? gmtime : localtime)(&guess_hi);
 629     if (!tm) goto error;
 630     d = tmcmp(tptr, tm);
 631     if (d > 0) goto out_of_range;
 632     if (d == 0) return guess_hi;
 633     tm_hi = *tm;
 634
 635     have_guess = 0;
 636
 637     while (guess_lo + 1 < guess_hi) {
 638         /* there is a gap between guess_lo and guess_hi. */
 639         unsigned long range = 0;
 640         if (!have_guess) {
 641             int a, b;
 642             /*
 643               Try precious guess by a linear interpolation at first.
 644               `a' and `b' is a coefficient of guess_lo and guess_hi as:
 645
 646                 guess = (guess_lo * a + guess_hi * b) / (a + b)
 647
 648               However this causes overflow in most cases, following assignment
 649               is used instead:
 650
 651                 guess = guess_lo / d * a + (guess_lo % d) * a / d
 652                         + guess_hi / d * b + (guess_hi % d) * b / d
 653                 where d = a + b
 654
 655               To avoid overflow in this assignment, `d' is restricted to less than
 656               sqrt(2**31).  By this restriction and other reasons, the guess is
 657               not accurate and some error is expected.  `range' approximates
 658               the maximum error.
 659
 660               When these parameters are not suitable, i.e. guess is not within
 661               guess_lo and guess_hi, simple guess by binary search is used.
 662             */
 663             range = 366 * 24 * 60 * 60;
 664             a = (tm_hi.tm_year - tptr->tm_year);
 665             b = (tptr->tm_year - tm_lo.tm_year);
 666             /* 46000 is selected as `some big number less than sqrt(2**31)'. */
 667             if (a + b <= 46000 / 12) {
 668                 range = 31 * 24 * 60 * 60;
 669                 a *= 12;
 670                 b *= 12;
 671                 a += tm_hi.tm_mon - tptr->tm_mon;
 672                 b += tptr->tm_mon - tm_lo.tm_mon;
 673                 if (a + b <= 46000 / 31) {
 674                     range = 24 * 60 * 60;
 675                     a *= 31;
 676                     b *= 31;
 677                     a += tm_hi.tm_mday - tptr->tm_mday;
 678                     b += tptr->tm_mday - tm_lo.tm_mday;
 679                     if (a + b <= 46000 / 24) {
 680                         range = 60 * 60;
 681                         a *= 24;
 682                         b *= 24;
 683                         a += tm_hi.tm_hour - tptr->tm_hour;
 684                         b += tptr->tm_hour - tm_lo.tm_hour;
 685                         if (a + b <= 46000 / 60) {
 686                             range = 60;
 687                             a *= 60;
 688                             b *= 60;
 689                             a += tm_hi.tm_min - tptr->tm_min;
 690                             b += tptr->tm_min - tm_lo.tm_min;
 691                             if (a + b <= 46000 / 60) {
 692                                 range = 1;
 693                                 a *= 60;
 694                                 b *= 60;
 695                                 a += tm_hi.tm_sec - tptr->tm_sec;
 696                                 b += tptr->tm_sec - tm_lo.tm_sec;
 697                             }
 698                         }
 699                     }
 700                 }
 701             }
 702             if (a <= 0) a = 1;
 703             if (b <= 0) b = 1;
 704             d = a + b;
 705             /*
 706               Although `/' and `%' may produce unexpected result with negative
 707               argument, it doesn't cause serious problem because there is a
 708               fail safe.
 709             */
 710             guess = guess_lo / d * a + (guess_lo % d) * a / d
 711                     + guess_hi / d * b + (guess_hi % d) * b / d;
 712             have_guess = 1;
 713         }
 714
 715         if (guess <= guess_lo || guess_hi <= guess) {
 716             /* Precious guess is invalid. try binary search. */
 717             guess = guess_lo / 2 + guess_hi / 2;
 718             if (guess <= guess_lo)
 719                 guess = guess_lo + 1;
 720             else if (guess >= guess_hi)
 721                 guess = guess_hi - 1;
 722             range = 0;
 723         }
 724
 725         tm = (utc_p ? gmtime : localtime)(&guess);
 726         if (!tm) goto error;
 727         have_guess = 0;
 728
 729         d = tmcmp(tptr, tm);
 730         if (d < 0) {
 731             guess_hi = guess;
 732             tm_hi = *tm;
 733             if (range) {
 734                 guess = guess - range;
 735                 range = 0;
 736                 if (guess_lo < guess && guess < guess_hi)
 737                     have_guess = 1;
 738             }
 739         }
 740         else if (d > 0) {
 741             guess_lo = guess;
 742             tm_lo = *tm;
 743             if (range) {
 744                 guess = guess + range;
 745                 range = 0;
 746                 if (guess_lo < guess && guess < guess_hi)
 747                     have_guess = 1;
 748             }
 749         }
 750         else {
 751             if (!utc_p) {
 752                 /* If localtime is nonmonotonic, another result may exist. */
 753                 time_t guess2;
 754                 if (find_dst) {
 755                     guess2 = guess - 2 * 60 * 60;
 756                     tm = localtime(&guess2);
 757                     if (tm) {
 758                         if (tptr->tm_hour != (tm->tm_hour + 2) % 24 ||
 759                             tptr->tm_min != tm->tm_min ||
 760                             tptr->tm_sec != tm->tm_sec
 761                         ) {
 762                             guess2 -= (tm->tm_hour - tptr->tm_hour) * 60 * 60 +
 763                                       (tm->tm_min - tptr->tm_min) * 60 +
 764                                       (tm->tm_sec - tptr->tm_sec);
 765                             if (tptr->tm_mday != tm->tm_mday)
 766                                 guess2 += 24 * 60 * 60;
 767                             if (guess != guess2) {
 768                                 tm = localtime(&guess2);
 769                                 if (tmcmp(tptr, tm) == 0) {
 770                                     if (guess < guess2)
 771                                         return guess;
 772                                     else
 773                                         return guess2;
 774                                 }
 775                             }
 776                         }
 777                     }
 778                 }
 779                 else {
 780                     guess2 = guess + 2 * 60 * 60;
 781                     tm = localtime(&guess2);
 782                     if (tm) {
 783                         if ((tptr->tm_hour + 2) % 24 != tm->tm_hour ||
 784                             tptr->tm_min != tm->tm_min ||
 785                             tptr->tm_sec != tm->tm_sec
 786                         ) {
 787                             guess2 -= (tm->tm_hour - tptr->tm_hour) * 60 * 60 +
 788                                       (tm->tm_min - tptr->tm_min) * 60 +
 789                                       (tm->tm_sec - tptr->tm_sec);
 790                             if (tptr->tm_mday != tm->tm_mday)
 791                                 guess2 -= 24 * 60 * 60;
 792                             if (guess != guess2) {
 793                                 tm = localtime(&guess2);
 794                                 if (tmcmp(tptr, tm) == 0) {
 795                                     if (guess < guess2)
 796                                         return guess2;
 797                                     else
 798                                         return guess;
 799                                 }
 800                             }
 801                         }
 802                     }
 803                 }
 804             }
 805             return guess;
 806         }
 807     }
 808     /* Given argument has no corresponding time_t. Let's outerpolation. */
 809     if (tm_lo.tm_year == tptr->tm_year && tm_lo.tm_mon == tptr->tm_mon) {
 810         return guess_lo +
 811                (tptr->tm_mday - tm_lo.tm_mday) * 24 * 60 * 60 +
 812                (tptr->tm_hour - tm_lo.tm_hour) * 60 * 60 +
 813                (tptr->tm_min - tm_lo.tm_min) * 60 +
 814                (tptr->tm_sec - tm_lo.tm_sec);
 815     }
 816     else if (tm_hi.tm_year == tptr->tm_year && tm_hi.tm_mon == tptr->tm_mon) {
 817         return guess_hi +
 818                (tptr->tm_mday - tm_hi.tm_mday) * 24 * 60 * 60 +
 819                (tptr->tm_hour - tm_hi.tm_hour) * 60 * 60 +
 820                (tptr->tm_min - tm_hi.tm_min) * 60 +
 821                (tptr->tm_sec - tm_hi.tm_sec);
 822     }
 823
 824   out_of_range:
 825     rb_raise(rb_eArgError, "time out of range");
 826
 827   error:
 828     rb_raise(rb_eArgError, "gmtime/localtime error");
 829     return 0;                   /* not reached */
 830 }
 831
 832 static time_t
 833 make_time_t(struct tm *tptr, int utc_p)
 834 {
 835     time_t t;
 836 #ifdef NEGATIVE_TIME_T
 837     struct tm *tmp;
 838 #endif
 839     struct tm buf;
 840     buf = *tptr;
 841     if (utc_p) {
 842 #if defined(HAVE_TIMEGM)
 843         if ((t = timegm(&buf)) != -1)
 844             return t;
 845 #ifdef NEGATIVE_TIME_T
 846         if ((tmp = gmtime(&t)) &&
 847             tptr->tm_year == tmp->tm_year &&
 848             tptr->tm_mon == tmp->tm_mon &&
 849             tptr->tm_mday == tmp->tm_mday &&
 850             tptr->tm_hour == tmp->tm_hour &&
 851             tptr->tm_min == tmp->tm_min &&
 852             tptr->tm_sec == tmp->tm_sec
 853         )
 854             return t;
 855 #endif
 856 #endif
 857         return search_time_t(&buf, utc_p);
 858     }
 859     else {
 860 #if defined(HAVE_MKTIME)
 861         if ((t = mktime(&buf)) != -1)
 862             return t;
 863 #ifdef NEGATIVE_TIME_T
 864         if ((tmp = localtime(&t)) &&
 865             tptr->tm_year == tmp->tm_year &&
 866             tptr->tm_mon == tmp->tm_mon &&
 867             tptr->tm_mday == tmp->tm_mday &&
 868             tptr->tm_hour == tmp->tm_hour &&
 869             tptr->tm_min == tmp->tm_min &&
 870             tptr->tm_sec == tmp->tm_sec
 871         )
 872             return t;
 873 #endif
 874 #endif
 875         return search_time_t(&buf, utc_p);
 876     }
 877 }
 878
 879 static VALUE
 880 time_utc_or_local(int argc, VALUE *argv, int utc_p, VALUE klass)
 881 {
 882     struct tm tm;
 883     VALUE time;
 884     long nsec;
 885
 886     time_arg(argc, argv, &tm, &nsec);
 887     time = time_new_internal(klass, make_time_t(&tm, utc_p), nsec);
 888     if (utc_p) return time_gmtime(time);
 889     return time_localtime(time);
 890 }
 891
 892 /*
 893  *  call-seq:
 894  *    Time.utc(year) => time
 895  *    Time.utc(year, month) => time
 896  *    Time.utc(year, month, day) => time
 897  *    Time.utc(year, month, day, hour) => time
 898  *    Time.utc(year, month, day, hour, min) => time
 899  *    Time.utc(year, month, day, hour, min, sec_with_frac) => time
 900  *    Time.utc(year, month, day, hour, min, sec, usec_with_frac) => time
 901  *    Time.utc(sec, min, hour, day, month, year, wday, yday, isdst, tz) => time
 902  *    Time.gm(year) => time
 903  *    Time.gm(year, month) => time
 904  *    Time.gm(year, month, day) => time
 905  *    Time.gm(year, month, day, hour) => time
 906  *    Time.gm(year, month, day, hour, min) => time
 907  *    Time.gm(year, month, day, hour, min, sec_with_frac) => time
 908  *    Time.gm(year, month, day, hour, min, sec, usec_with_frac) => time
 909  *    Time.gm(sec, min, hour, day, month, year, wday, yday, isdst, tz) => time
 910  *
 911  *  Creates a time based on given values, interpreted as UTC (GMT). The
 912  *  year must be specified. Other values default to the minimum value
 913  *  for that field (and may be <code>nil</code> or omitted). Months may
 914  *  be specified by numbers from 1 to 12, or by the three-letter English
 915  *  month names. Hours are specified on a 24-hour clock (0..23). Raises
 916  *  an <code>ArgumentError</code> if any values are out of range. Will
 917  *  also accept ten arguments in the order output by
 918  *  <code>Time#to_a</code>.
 919  *  <i>sec_with_frac</i> and <i>usec_with_frac</i> can have a fractional part.
 920  *
 921  *     Time.utc(2000,"jan",1,20,15,1)  #=> 2000-01-01 20:15:01 UTC
 922  *     Time.gm(2000,"jan",1,20,15,1)   #=> 2000-01-01 20:15:01 UTC
 923  */
 924 static VALUE
 925 time_s_mkutc(int argc, VALUE *argv, VALUE klass)
 926 {
 927     return time_utc_or_local(argc, argv, Qtrue, klass);
 928 }
 929
 930 /*
 931  *  call-seq:
 932  *   Time.local(year) => time
 933  *   Time.local(year, month) => time
 934  *   Time.local(year, month, day) => time
 935  *   Time.local(year, month, day, hour) => time
 936  *   Time.local(year, month, day, hour, min) => time
 937  *   Time.local(year, month, day, hour, min, sec_with_frac) => time
 938  *   Time.local(year, month, day, hour, min, sec, usec_with_frac) => time
 939  *   Time.local(sec, min, hour, day, month, year, wday, yday, isdst, tz) => time
 940  *   Time.mktime(year) => time
 941  *   Time.mktime(year, month) => time
 942  *   Time.mktime(year, month, day) => time
 943  *   Time.mktime(year, month, day, hour) => time
 944  *   Time.mktime(year, month, day, hour, min) => time
 945  *   Time.mktime(year, month, day, hour, min, sec_with_frac) => time
 946  *   Time.mktime(year, month, day, hour, min, sec, usec_with_frac) => time
 947  *   Time.mktime(sec, min, hour, day, month, year, wday, yday, isdst, tz) => time
 948  *
 949  *  Same as <code>Time::gm</code>, but interprets the values in the
 950  *  local time zone.
 951  *
 952  *     Time.local(2000,"jan",1,20,15,1)   #=> 2000-01-01 20:15:01 -0600
 953  */
 954
 955 static VALUE
 956 time_s_mktime(int argc, VALUE *argv, VALUE klass)
 957 {
 958     return time_utc_or_local(argc, argv, Qfalse, klass);
 959 }
 960
 961 /*
 962  *  call-seq:
 963  *     time.to_i   => int
 964  *     time.tv_sec => int
 965  *
 966  *  Returns the value of <i>time</i> as an integer number of seconds
 967  *  since the Epoch.
 968  *
 969  *     t = Time.now
 970  *     "%10.5f" % t.to_f   #=> "1049896564.17839"
 971  *     t.to_i              #=> 1049896564
 972  */
 973
 974 static VALUE
 975 time_to_i(VALUE time)
 976 {
 977     struct time_object *tobj;
 978
 979     GetTimeval(time, tobj);
 980     return LONG2NUM(tobj->ts.tv_sec);
 981 }
 982
 983 /*
 984  *  call-seq:
 985  *     time.to_f => float
 986  *
 987  *  Returns the value of <i>time</i> as a floating point number of
 988  *  seconds since the Epoch.
 989  *
 990  *     t = Time.now
 991  *     "%10.5f" % t.to_f   #=> "1049896564.13654"
 992  *     t.to_i              #=> 1049896564
 993  *
 994  *  Note that IEEE 754 double is not accurate enough to represent
 995  *  nanoseconds from the Epoch.
 996  */
 997
 998 static VALUE
 999 time_to_f(VALUE time)
1000 {
1001     struct time_object *tobj;
1002
1003     GetTimeval(time, tobj);
1004     return DOUBLE2NUM((double)tobj->ts.tv_sec+(double)tobj->ts.tv_nsec/1e9);
1005 }
1006
1007 /*
1008  *  call-seq:
1009  *     time.usec    => int
1010  *     time.tv_usec => int
1011  *
1012  *  Returns just the number of microseconds for <i>time</i>.
1013  *
1014  *     t = Time.now        #=> 2007-11-19 08:03:26 -0600
1015  *     "%10.6f" % t.to_f   #=> "1195481006.775195"
1016  *     t.usec              #=> 775195
1017  */
1018
1019 static VALUE
1020 time_usec(VALUE time)
1021 {
1022     struct time_object *tobj;
1023
1024     GetTimeval(time, tobj);
1025     return LONG2NUM(tobj->ts.tv_nsec/1000);
1026 }
1027
1028 /*
1029  *  call-seq:
1030  *     time.nsec    => int
1031  *     time.tv_nsec => int
1032  *
1033  *  Returns just the number of nanoseconds for <i>time</i>.
1034  *
1035  *     t = Time.now        #=> 2007-11-17 15:18:03 +0900
1036  *     "%10.9f" % t.to_f   #=> "1195280283.536151409"
1037  *     t.nsec              #=> 536151406
1038  *
1039  *  The lowest digit of to_f and nsec is different because
1040  *  IEEE 754 double is not accurate enough to represent
1041  *  nanoseconds from the Epoch.
1042  *  The accurate value is returned by nsec.
1043  */
1044
1045 static VALUE
1046 time_nsec(VALUE time)
1047 {
1048     struct time_object *tobj;
1049
1050     GetTimeval(time, tobj);
1051     return LONG2NUM(tobj->ts.tv_nsec);
1052 }
1053
1054 /*
1055  *  call-seq:
1056  *     time <=> other_time => -1, 0, +1
1057  *
1058  *  Comparison---Compares <i>time</i> with <i>other_time</i>.
1059  *
1060  *     t = Time.now       #=> 2007-11-19 08:12:12 -0600
1061  *     t2 = t + 2592000   #=> 2007-12-19 08:12:12 -0600
1062  *     t <=> t2           #=> -1
1063  *     t2 <=> t           #=> 1
1064  *
1065  *     t = Time.now       #=> 2007-11-19 08:13:38 -0600
1066  *     t2 = t + 0.1       #=> 2007-11-19 08:13:38 -0600
1067  *     t.nsec             #=> 98222999
1068  *     t2.nsec            #=> 198222999
1069  *     t <=> t2           #=> -1
1070  *     t2 <=> t           #=> 1
1071  *     t <=> t            #=> 0
1072  */
1073
1074 static VALUE
1075 time_cmp(VALUE time1, VALUE time2)
1076 {
1077     struct time_object *tobj1, *tobj2;
1078
1079     GetTimeval(time1, tobj1);
1080     if (TYPE(time2) == T_DATA && RDATA(time2)->dfree == time_free) {
1081         GetTimeval(time2, tobj2);
1082         if (tobj1->ts.tv_sec == tobj2->ts.tv_sec) {
1083             if (tobj1->ts.tv_nsec == tobj2->ts.tv_nsec) return INT2FIX(0);
1084             if (tobj1->ts.tv_nsec > tobj2->ts.tv_nsec) return INT2FIX(1);
1085             return INT2FIX(-1);
1086         }
1087         if (tobj1->ts.tv_sec > tobj2->ts.tv_sec) return INT2FIX(1);
1088         return INT2FIX(-1);
1089     }
1090     else {
1091         VALUE cmp;
1092         int n;
1093
1094         cmp = rb_funcall(time2, rb_intern("<=>"), 1, time1);
1095         if (NIL_P(cmp)) return Qnil;
1096
1097         n = rb_cmpint(cmp, time1, time2);
1098         if (n == 0) return INT2FIX(0);
1099         if (n > 0) return INT2FIX(1);
1100         return INT2FIX(-1);
1101     }
1102 }
1103
1104 /*
1105  * call-seq:
1106  *  time.eql?(other_time)
1107  *
1108  * Return <code>true</code> if <i>time</i> and <i>other_time</i> are
1109  * both <code>Time</code> objects with the same seconds and fractional
1110  * seconds.
1111  */
1112
1113 static VALUE
1114 time_eql(VALUE time1, VALUE time2)
1115 {
1116     struct time_object *tobj1, *tobj2;
1117
1118     GetTimeval(time1, tobj1);
1119     if (TYPE(time2) == T_DATA && RDATA(time2)->dfree == time_free) {
1120         GetTimeval(time2, tobj2);
1121         if (tobj1->ts.tv_sec == tobj2->ts.tv_sec) {
1122             if (tobj1->ts.tv_nsec == tobj2->ts.tv_nsec) return Qtrue;
1123         }
1124     }
1125     return Qfalse;
1126 }
1127
1128 /*
1129  *  call-seq:
1130  *     time.utc? => true or false
1131  *     time.gmt? => true or false
1132  *
1133  *  Returns <code>true</code> if <i>time</i> represents a time in UTC
1134  *  (GMT).
1135  *
1136  *     t = Time.now                        #=> 2007-11-19 08:15:23 -0600
1137  *     t.utc?                              #=> false
1138  *     t = Time.gm(2000,"jan",1,20,15,1)   #=> 2000-01-01 20:15:01 UTC
1139  *     t.utc?                              #=> true
1140  *
1141  *     t = Time.now                        #=> 2007-11-19 08:16:03 -0600
1142  *     t.gmt?                              #=> false
1143  *     t = Time.gm(2000,1,1,20,15,1)       #=> 2000-01-01 20:15:01 UTC
1144  *     t.gmt?                              #=> true
1145  */
1146
1147 static VALUE
1148 time_utc_p(VALUE time)
1149 {
1150     struct time_object *tobj;
1151
1152     GetTimeval(time, tobj);
1153     if (tobj->gmt) return Qtrue;
1154     return Qfalse;
1155 }
1156
1157 /*
1158  * call-seq:
1159  *   time.hash   => fixnum
1160  *
1161  * Return a hash code for this time object.
1162  */
1163
1164 static VALUE
1165 time_hash(VALUE time)
1166 {
1167     struct time_object *tobj;
1168     long hash;
1169
1170     GetTimeval(time, tobj);
1171     hash = tobj->ts.tv_sec ^ tobj->ts.tv_nsec;
1172     return LONG2FIX(hash);
1173 }
1174
1175 /* :nodoc: */
1176 static VALUE
1177 time_init_copy(VALUE copy, VALUE time)
1178 {
1179     struct time_object *tobj, *tcopy;
1180
1181     if (copy == time) return copy;
1182     time_modify(copy);
1183     if (TYPE(time) != T_DATA || RDATA(time)->dfree != time_free) {
1184         rb_raise(rb_eTypeError, "wrong argument type");
1185     }
1186     GetTimeval(time, tobj);
1187     GetTimeval(copy, tcopy);
1188     MEMCPY(tcopy, tobj, struct time_object, 1);
1189
1190     return copy;
1191 }
1192
1193 static VALUE
1194 time_dup(VALUE time)
1195 {
1196     VALUE dup = time_s_alloc(CLASS_OF(time));
1197     time_init_copy(dup, time);
1198     return dup;
1199 }
1200
1201 /*
1202  *  call-seq:
1203  *     time.localtime => time
1204  *
1205  *  Converts <i>time</i> to local time (using the local time zone in
1206  *  effect for this process) modifying the receiver.
1207  *
1208  *     t = Time.gm(2000, "jan", 1, 20, 15, 1)  #=> 2000-01-01 20:15:01 UTC
1209  *     t.gmt?                                  #=> true
1210  *     t.localtime                             #=> 2000-01-01 14:15:01 -0600
1211  *     t.gmt?                                  #=> false
1212  */
1213
1214 static VALUE
1215 time_localtime(VALUE time)
1216 {
1217     struct time_object *tobj;
1218     struct tm *tm_tmp;
1219     time_t t;
1220
1221     GetTimeval(time, tobj);
1222     if (!tobj->gmt) {
1223         if (tobj->tm_got)
1224             return time;
1225     }
1226     else {
1227         time_modify(time);
1228     }
1229     t = tobj->ts.tv_sec;
1230     tm_tmp = localtime(&t);
1231     if (!tm_tmp)
1232         rb_raise(rb_eArgError, "localtime error");
1233     tobj->tm = *tm_tmp;
1234     tobj->tm_got = 1;
1235     tobj->gmt = 0;
1236     return time;
1237 }
1238
1239 /*
1240  *  call-seq:
1241  *     time.gmtime    => time
1242  *     time.utc       => time
1243  *
1244  *  Converts <i>time</i> to UTC (GMT), modifying the receiver.
1245  *
1246  *     t = Time.now   #=> 2007-11-19 08:18:31 -0600
1247  *     t.gmt?         #=> false
1248  *     t.gmtime       #=> 2007-11-19 14:18:31 UTC
1249  *     t.gmt?         #=> true
1250  *
1251  *     t = Time.now   #=> 2007-11-19 08:18:51 -0600
1252  *     t.utc?         #=> false
1253  *     t.utc          #=> 2007-11-19 14:18:51 UTC
1254  *     t.utc?         #=> true
1255  */
1256
1257 static VALUE
1258 time_gmtime(VALUE time)
1259 {
1260     struct time_object *tobj;
1261     struct tm *tm_tmp;
1262     time_t t;
1263
1264     GetTimeval(time, tobj);
1265     if (tobj->gmt) {
1266         if (tobj->tm_got)
1267             return time;
1268     }
1269     else {
1270         time_modify(time);
1271     }
1272     t = tobj->ts.tv_sec;
1273     tm_tmp = gmtime(&t);
1274     if (!tm_tmp)
1275         rb_raise(rb_eArgError, "gmtime error");
1276     tobj->tm = *tm_tmp;
1277     tobj->tm_got = 1;
1278     tobj->gmt = 1;
1279     return time;
1280 }
1281
1282 /*
1283  *  call-seq:
1284  *     time.getlocal => new_time
1285  *
1286  *  Returns a new <code>new_time</code> object representing <i>time</i> in
1287  *  local time (using the local time zone in effect for this process).
1288  *
1289  *     t = Time.gm(2000,1,1,20,15,1)   #=> 2000-01-01 20:15:01 UTC
1290  *     t.gmt?                          #=> true
1291  *     l = t.getlocal                  #=> 2000-01-01 14:15:01 -0600
1292  *     l.gmt?                          #=> false
1293  *     t == l                          #=> true
1294  */
1295
1296 static VALUE
1297 time_getlocaltime(VALUE time)
1298 {
1299     return time_localtime(time_dup(time));
1300 }
1301
1302 /*
1303  *  call-seq:
1304  *     time.getgm  => new_time
1305  *     time.getutc => new_time
1306  *
1307  *  Returns a new <code>new_time</code> object representing <i>time</i> in
1308  *  UTC.
1309  *
1310  *     t = Time.local(2000,1,1,20,15,1)   #=> 2000-01-01 20:15:01 -0600
1311  *     t.gmt?                             #=> false
1312  *     y = t.getgm                        #=> 2000-01-02 02:15:01 UTC
1313  *     y.gmt?                             #=> true
1314  *     t == y                             #=> true
1315  */
1316
1317 static VALUE
1318 time_getgmtime(VALUE time)
1319 {
1320     return time_gmtime(time_dup(time));
1321 }
1322
1323 static VALUE
1324 time_get_tm(VALUE time, int gmt)
1325 {
1326     if (gmt) return time_gmtime(time);
1327     return time_localtime(time);
1328 }
1329
1330 /*
1331  *  call-seq:
1332  *     time.asctime => string
1333  *     time.ctime   => string
1334  *
1335  *  Returns a canonical string representation of <i>time</i>.
1336  *
1337  *     Time.now.asctime   #=> "Wed Apr  9 08:56:03 2003"
1338  */
1339
1340 static VALUE
1341 time_asctime(VALUE time)
1342 {
1343     struct time_object *tobj;
1344     char *s;
1345
1346     GetTimeval(time, tobj);
1347     if (tobj->tm_got == 0) {
1348         time_get_tm(time, tobj->gmt);
1349     }
1350     s = asctime(&tobj->tm);
1351     if (s[24] == '\n') s[24] = '\0';
1352
1353     return rb_str_new2(s);
1354 }
1355
1356 /*
1357  *  call-seq:
1358  *     time.inspect => string
1359  *     time.to_s    => string
1360  *
1361  *  Returns a string representing <i>time</i>. Equivalent to calling
1362  *  <code>Time#strftime</code> with a format string of
1363  *  ``<code>%Y-%m-%d</code> <code>%H:%M:%S</code> <code>%z</code>''
1364  *  for a local time and
1365  *  ``<code>%Y-%m-%d</code> <code>%H:%M:%S</code> <code>UTC</code>''
1366  *  for a UTC time.
1367  *
1368  *     Time.now.to_s       #=> "2007-10-05 16:09:51 +0900"
1369  *     Time.now.utc.to_s   #=> "2007-10-05 07:09:51 UTC"
1370  */
1371
1372 static VALUE
1373 time_to_s(VALUE time)
1374 {
1375     struct time_object *tobj;
1376     char buf[128];
1377     int len;
1378
1379     GetTimeval(time, tobj);
1380     if (tobj->tm_got == 0) {
1381         time_get_tm(time, tobj->gmt);
1382     }
1383     if (tobj->gmt == 1) {
1384         len = strftime(buf, 128, "%Y-%m-%d %H:%M:%S UTC", &tobj->tm);
1385     }
1386     else {
1387         long off;
1388         char sign = '+';
1389 #if defined(HAVE_STRUCT_TM_TM_GMTOFF)
1390         off = tobj->tm.tm_gmtoff;
1391 #else
1392         VALUE tmp = time_utc_offset(time);
1393         off = NUM2INT(tmp);
1394 #endif
1395         if (off < 0) {
1396             sign = '-';
1397             off = -off;
1398         }
1399         len = strftime(buf, sizeof(buf), "%Y-%m-%d %H:%M:%S ", &tobj->tm);
1400         len += snprintf(buf+len, sizeof(buf)-len, "%c%02d%02d", sign,
1401                         (int)(off/3600), (int)(off%3600/60));
1402     }
1403     return rb_str_new(buf, len);
1404 }
1405
1406 static VALUE
1407 time_add(struct time_object *tobj, VALUE offset, int sign)
1408 {
1409     double v = NUM2DBL(offset);
1410     double f, d;
1411     unsigned_time_t sec_off;
1412     time_t sec;
1413     long nsec_off, nsec;
1414     VALUE result;
1415
1416     if (v < 0) {
1417         v = -v;
1418         sign = -sign;
1419     }
1420     d = modf(v, &f);
1421     sec_off = (unsigned_time_t)f;
1422     if (f != (double)sec_off)
1423         rb_raise(rb_eRangeError, "time %s %f out of Time range",
1424                  sign < 0 ? "-" : "+", v);
1425     nsec_off = (long)(d*1e9+0.5);
1426
1427     if (sign < 0) {
1428         sec = tobj->ts.tv_sec - sec_off;
1429         nsec = tobj->ts.tv_nsec - nsec_off;
1430         if (sec > tobj->ts.tv_sec)
1431             rb_raise(rb_eRangeError, "time - %f out of Time range", v);
1432     }
1433     else {
1434         sec = tobj->ts.tv_sec + sec_off;
1435         nsec = tobj->ts.tv_nsec + nsec_off;
1436         if (sec < tobj->ts.tv_sec)
1437             rb_raise(rb_eRangeError, "time + %f out of Time range", v);
1438     }
1439     result = rb_time_nano_new(sec, nsec);
1440     if (tobj->gmt) {
1441         GetTimeval(result, tobj);
1442         tobj->gmt = 1;
1443     }
1444     return result;
1445 }
1446
1447 /*
1448  *  call-seq:
1449  *     time + numeric => time
1450  *
1451  *  Addition---Adds some number of seconds (possibly fractional) to
1452  *  <i>time</i> and returns that value as a new time.
1453  *
1454  *     t = Time.now         #=> 2007-11-19 08:22:21 -0600
1455  *     t + (60 * 60 * 24)   #=> 2007-11-20 08:22:21 -0600
1456  */
1457
1458 static VALUE
1459 time_plus(VALUE time1, VALUE time2)
1460 {
1461     struct time_object *tobj;
1462     GetTimeval(time1, tobj);
1463
1464     if (TYPE(time2) == T_DATA && RDATA(time2)->dfree == time_free) {
1465         rb_raise(rb_eTypeError, "time + time?");
1466     }
1467     return time_add(tobj, time2, 1);
1468 }
1469
1470 /*
1471  *  call-seq:
1472  *     time - other_time => float
1473  *     time - numeric    => time
1474  *
1475  *  Difference---Returns a new time that represents the difference
1476  *  between two times, or subtracts the given number of seconds in
1477  *  <i>numeric</i> from <i>time</i>.
1478  *
1479  *     t = Time.now       #=> 2007-11-19 08:23:10 -0600
1480  *     t2 = t + 2592000   #=> 2007-12-19 08:23:10 -0600
1481  *     t2 - t             #=> 2592000.0
1482  *     t2 - 2592000       #=> 2007-11-19 08:23:10 -0600
1483  */
1484
1485 static VALUE
1486 time_minus(VALUE time1, VALUE time2)
1487 {
1488     struct time_object *tobj;
1489
1490     GetTimeval(time1, tobj);
1491     if (TYPE(time2) == T_DATA && RDATA(time2)->dfree == time_free) {
1492         struct time_object *tobj2;
1493         double f;
1494
1495         GetTimeval(time2, tobj2);
1496         if (tobj->ts.tv_sec < tobj2->ts.tv_sec)
1497             f = -(double)(unsigned_time_t)(tobj2->ts.tv_sec - tobj->ts.tv_sec);
1498         else
1499             f = (double)(unsigned_time_t)(tobj->ts.tv_sec - tobj2->ts.tv_sec);
1500         f += ((double)tobj->ts.tv_nsec - (double)tobj2->ts.tv_nsec)*1e-9;
1501
1502         return DOUBLE2NUM(f);
1503     }
1504     return time_add(tobj, time2, -1);
1505 }
1506
1507 /*
1508  * call-seq:
1509  *   time.succ   => new_time
1510  *
1511  * Return a new time object, one second later than <code>time</code>.
1512  *
1513  *     t = Time.now       #=> 2007-11-19 08:23:57 -0600
1514  *     t.succ             #=> 2007-11-19 08:23:58 -0600
1515  */
1516
1517 static VALUE
1518 time_succ(VALUE time)
1519 {
1520     struct time_object *tobj;
1521     int gmt;
1522
1523     GetTimeval(time, tobj);
1524     gmt = tobj->gmt;
1525     time = rb_time_nano_new(tobj->ts.tv_sec + 1, tobj->ts.tv_nsec);
1526     GetTimeval(time, tobj);
1527     tobj->gmt = gmt;
1528     return time;
1529 }
1530
1531 VALUE
1532 rb_time_succ(VALUE time)
1533 {
1534   return time_succ(time);
1535 }
1536
1537 /*
1538  *  call-seq:
1539  *     time.sec => fixnum
1540  *
1541  *  Returns the second of the minute (0..60)<em>[Yes, seconds really can
1542  *  range from zero to 60. This allows the system to inject leap seconds
1543  *  every now and then to correct for the fact that years are not really
1544  *  a convenient number of hours long.]</em> for <i>time</i>.
1545  *
1546  *     t = Time.now   #=> 2007-11-19 08:25:02 -0600
1547  *     t.sec          #=> 2
1548  */
1549
1550 static VALUE
1551 time_sec(VALUE time)
1552 {
1553     struct time_object *tobj;
1554
1555     GetTimeval(time, tobj);
1556     if (tobj->tm_got == 0) {
1557         time_get_tm(time, tobj->gmt);
1558     }
1559     return INT2FIX(tobj->tm.tm_sec);
1560 }
1561
1562 /*
1563  *  call-seq:
1564  *     time.min => fixnum
1565  *
1566  *  Returns the minute of the hour (0..59) for <i>time</i>.
1567  *
1568  *     t = Time.now   #=> 2007-11-19 08:25:51 -0600
1569  *     t.min          #=> 25
1570  */
1571
1572 static VALUE
1573 time_min(VALUE time)
1574 {
1575     struct time_object *tobj;
1576
1577     GetTimeval(time, tobj);
1578     if (tobj->tm_got == 0) {
1579         time_get_tm(time, tobj->gmt);
1580     }
1581     return INT2FIX(tobj->tm.tm_min);
1582 }
1583
1584 /*
1585  *  call-seq:
1586  *     time.hour => fixnum
1587  *
1588  *  Returns the hour of the day (0..23) for <i>time</i>.
1589  *
1590  *     t = Time.now   #=> 2007-11-19 08:26:20 -0600
1591  *     t.hour         #=> 8
1592  */
1593
1594 static VALUE
1595 time_hour(VALUE time)
1596 {
1597     struct time_object *tobj;
1598
1599     GetTimeval(time, tobj);
1600     if (tobj->tm_got == 0) {
1601         time_get_tm(time, tobj->gmt);
1602     }
1603     return INT2FIX(tobj->tm.tm_hour);
1604 }
1605
1606 /*
1607  *  call-seq:
1608  *     time.day  => fixnum
1609  *     time.mday => fixnum
1610  *
1611  *  Returns the day of the month (1..n) for <i>time</i>.
1612  *
1613  *     t = Time.now   #=> 2007-11-19 08:27:03 -0600
1614  *     t.day          #=> 19
1615  *     t.mday         #=> 19
1616  */
1617
1618 static VALUE
1619 time_mday(VALUE time)
1620 {
1621     struct time_object *tobj;
1622
1623     GetTimeval(time, tobj);
1624     if (tobj->tm_got == 0) {
1625         time_get_tm(time, tobj->gmt);
1626     }
1627     return INT2FIX(tobj->tm.tm_mday);
1628 }
1629
1630 /*
1631  *  call-seq:
1632  *     time.mon   => fixnum
1633  *     time.month => fixnum
1634  *
1635  *  Returns the month of the year (1..12) for <i>time</i>.
1636  *
1637  *     t = Time.now   #=> 2007-11-19 08:27:30 -0600
1638  *     t.mon          #=> 11
1639  *     t.month        #=> 11
1640  */
1641
1642 static VALUE
1643 time_mon(VALUE time)
1644 {
1645     struct time_object *tobj;
1646
1647     GetTimeval(time, tobj);
1648     if (tobj->tm_got == 0) {
1649         time_get_tm(time, tobj->gmt);
1650     }
1651     return INT2FIX(tobj->tm.tm_mon+1);
1652 }
1653
1654 /*
1655  *  call-seq:
1656  *     time.year => fixnum
1657  *
1658  *  Returns the year for <i>time</i> (including the century).
1659  *
1660  *     t = Time.now   #=> 2007-11-19 08:27:51 -0600
1661  *     t.year         #=> 2007
1662  */
1663
1664 static VALUE
1665 time_year(VALUE time)
1666 {
1667     struct time_object *tobj;
1668
1669     GetTimeval(time, tobj);
1670     if (tobj->tm_got == 0) {
1671         time_get_tm(time, tobj->gmt);
1672     }
1673     return LONG2NUM((long)tobj->tm.tm_year+1900);
1674 }
1675
1676 /*
1677  *  call-seq:
1678  *     time.wday => fixnum
1679  *
1680  *  Returns an integer representing the day of the week, 0..6, with
1681  *  Sunday == 0.
1682  *
1683  *     t = Time.now   #=> 2007-11-20 02:35:35 -0600
1684  *     t.wday         #=> 2
1685  *     t.sunday?      #=> false
1686  *     t.monday?      #=> false
1687  *     t.tuesday?     #=> true
1688  *     t.wednesday?   #=> false
1689  *     t.thursday?    #=> false
1690  *     t.friday?      #=> false
1691  *     t.saturday?    #=> false
1692  */
1693
1694 static VALUE
1695 time_wday(VALUE time)
1696 {
1697     struct time_object *tobj;
1698
1699     GetTimeval(time, tobj);
1700     if (tobj->tm_got == 0) {
1701         time_get_tm(time, tobj->gmt);
1702     }
1703     return INT2FIX(tobj->tm.tm_wday);
1704 }
1705
1706 #define wday_p(n) {\
1707     struct time_object *tobj;\
1708     GetTimeval(time, tobj);\
1709     if (tobj->tm_got == 0) {\
1710         time_get_tm(time, tobj->gmt);\
1711     }\
1712     return (tobj->tm.tm_wday == (n)) ? Qtrue : Qfalse;\
1713 }
1714
1715 /*
1716  *  call-seq:
1717  *     time.sunday? => true or false
1718  *
1719  *  Returns <code>true</code> if <i>time</i> represents Sunday.
1720  *
1721  *     t = Time.local(1990, 4, 1)       #=> 1990-04-01 00:00:00 -0600
1722  *     t.sunday?                        #=> true
1723  */
1724
1725 static VALUE
1726 time_sunday(VALUE time)
1727 {
1728     wday_p(0);
1729 }
1730
1731 /*
1732  *  call-seq:
1733  *     time.monday? => true or false
1734  *
1735  *  Returns <code>true</code> if <i>time</i> represents Monday.
1736  *
1737  *     t = Time.local(2003, 8, 4)       #=> 2003-08-04 00:00:00 -0500
1738  *     p t.monday?                      #=> true
1739  */
1740
1741 static VALUE
1742 time_monday(VALUE time)
1743 {
1744     wday_p(1);
1745 }
1746
1747 /*
1748  *  call-seq:
1749  *     time.tuesday? => true or false
1750  *
1751  *  Returns <code>true</code> if <i>time</i> represents Tuesday.
1752  *
1753  *     t = Time.local(1991, 2, 19)      #=> 1991-02-19 00:00:00 -0600
1754  *     p t.tuesday?                     #=> true
1755  */
1756
1757 static VALUE
1758 time_tuesday(VALUE time)
1759 {
1760     wday_p(2);
1761 }
1762
1763 /*
1764  *  call-seq:
1765  *     time.wednesday? => true or false
1766  *
1767  *  Returns <code>true</code> if <i>time</i> represents Wednesday.
1768  *
1769  *     t = Time.local(1993, 2, 24)      #=> 1993-02-24 00:00:00 -0600
1770  *     p t.wednesday?                   #=> true
1771  */
1772
1773 static VALUE
1774 time_wednesday(VALUE time)
1775 {
1776     wday_p(3);
1777 }
1778
1779 /*
1780  *  call-seq:
1781  *     time.thursday? => true or false
1782  *
1783  *  Returns <code>true</code> if <i>time</i> represents Thursday.
1784  *
1785  *     t = Time.local(1995, 12, 21)     #=> 1995-12-21 00:00:00 -0600
1786  *     p t.thursday?                    #=> true
1787  */
1788
1789 static VALUE
1790 time_thursday(VALUE time)
1791 {
1792     wday_p(4);
1793 }
1794
1795 /*
1796  *  call-seq:
1797  *     time.friday? => true or false
1798  *
1799  *  Returns <code>true</code> if <i>time</i> represents Friday.
1800  *
1801  *     t = Time.local(1987, 12, 18)     #=> 1987-12-18 00:00:00 -0600
1802  *     t.friday?                        #=> true
1803  */
1804
1805 static VALUE
1806 time_friday(VALUE time)
1807 {
1808     wday_p(5);
1809 }
1810
1811 /*
1812  *  call-seq:
1813  *     time.saturday? => true or false
1814  *
1815  *  Returns <code>true</code> if <i>time</i> represents Saturday.
1816  *
1817  *     t = Time.local(2006, 6, 10)      #=> 2006-06-10 00:00:00 -0500
1818  *     t.saturday?                      #=> true
1819  */
1820
1821 static VALUE
1822 time_saturday(VALUE time)
1823 {
1824     wday_p(6);
1825 }
1826
1827 /*
1828  *  call-seq:
1829  *     time.yday => fixnum
1830  *
1831  *  Returns an integer representing the day of the year, 1..366.
1832  *
1833  *     t = Time.now   #=> 2007-11-19 08:32:31 -0600
1834  *     t.yday         #=> 323
1835  */
1836
1837 static VALUE
1838 time_yday(VALUE time)
1839 {
1840     struct time_object *tobj;
1841
1842     GetTimeval(time, tobj);
1843     if (tobj->tm_got == 0) {
1844         time_get_tm(time, tobj->gmt);
1845     }
1846     return INT2FIX(tobj->tm.tm_yday+1);
1847 }
1848
1849 /*
1850  *  call-seq:
1851  *     time.isdst => true or false
1852  *     time.dst?  => true or false
1853  *
1854  *  Returns <code>true</code> if <i>time</i> occurs during Daylight
1855  *  Saving Time in its time zone.
1856  *
1857  *   # CST6CDT:
1858  *     Time.local(2000, 1, 1).zone    #=> "CST"
1859  *     Time.local(2000, 1, 1).isdst   #=> false
1860  *     Time.local(2000, 1, 1).dst?    #=> false
1861  *     Time.local(2000, 7, 1).zone    #=> "CDT"
1862  *     Time.local(2000, 7, 1).isdst   #=> true
1863  *     Time.local(2000, 7, 1).dst?    #=> true
1864  *
1865  *   # Asia/Tokyo:
1866  *     Time.local(2000, 1, 1).zone    #=> "JST"
1867  *     Time.local(2000, 1, 1).isdst   #=> false
1868  *     Time.local(2000, 1, 1).dst?    #=> false
1869  *     Time.local(2000, 7, 1).zone    #=> "JST"
1870  *     Time.local(2000, 7, 1).isdst   #=> false
1871  *     Time.local(2000, 7, 1).dst?    #=> false
1872  */
1873
1874 static VALUE
1875 time_isdst(VALUE time)
1876 {
1877     struct time_object *tobj;
1878
1879     GetTimeval(time, tobj);
1880     if (tobj->tm_got == 0) {
1881         time_get_tm(time, tobj->gmt);
1882     }
1883     return tobj->tm.tm_isdst?Qtrue:Qfalse;
1884 }
1885
1886 /*
1887  *  call-seq:
1888  *     time.zone => string
1889  *
1890  *  Returns the name of the time zone used for <i>time</i>. As of Ruby
1891  *  1.8, returns ``UTC'' rather than ``GMT'' for UTC times.
1892  *
1893  *     t = Time.gm(2000, "jan", 1, 20, 15, 1)
1894  *     t.zone   #=> "UTC"
1895  *     t = Time.local(2000, "jan", 1, 20, 15, 1)
1896  *     t.zone   #=> "CST"
1897  */
1898
1899 static VALUE
1900 time_zone(VALUE time)
1901 {
1902     struct time_object *tobj;
1903 #if !defined(HAVE_TM_ZONE) && (!defined(HAVE_TZNAME) || !defined(HAVE_DAYLIGHT))
1904     char buf[64];
1905     int len;
1906 #endif
1907
1908     GetTimeval(time, tobj);
1909     if (tobj->tm_got == 0) {
1910         time_get_tm(time, tobj->gmt);
1911     }
1912
1913     if (tobj->gmt == 1) {
1914         return rb_str_new2("UTC");
1915     }
1916 #if defined(HAVE_TM_ZONE)
1917     return rb_str_new2(tobj->tm.tm_zone);
1918 #elif defined(HAVE_TZNAME) && defined(HAVE_DAYLIGHT)
1919     return rb_str_new2(tzname[daylight && tobj->tm.tm_isdst]);
1920 #else
1921     len = strftime(buf, 64, "%Z", &tobj->tm);
1922     return rb_str_new(buf, len);
1923 #endif
1924 }
1925
1926 /*
1927  *  call-seq:
1928  *     time.gmt_offset => fixnum
1929  *     time.gmtoff     => fixnum
1930  *     time.utc_offset => fixnum
1931  *
1932  *  Returns the offset in seconds between the timezone of <i>time</i>
1933  *  and UTC.
1934  *
1935  *     t = Time.gm(2000,1,1,20,15,1)   #=> 2000-01-01 20:15:01 UTC
1936  *     t.gmt_offset                    #=> 0
1937  *     l = t.getlocal                  #=> 2000-01-01 14:15:01 -0600
1938  *     l.gmt_offset                    #=> -21600
1939  */
1940
1941 static VALUE
1942 time_utc_offset(VALUE time)
1943 {
1944     struct time_object *tobj;
1945
1946     GetTimeval(time, tobj);
1947     if (tobj->tm_got == 0) {
1948         time_get_tm(time, tobj->gmt);
1949     }
1950
1951     if (tobj->gmt == 1) {
1952         return INT2FIX(0);
1953     }
1954     else {
1955 #if defined(HAVE_STRUCT_TM_TM_GMTOFF)
1956         return INT2NUM(tobj->tm.tm_gmtoff);
1957 #else
1958         struct tm *u, *l;
1959         time_t t;
1960         long off;
1961         l = &tobj->tm;
1962         t = tobj->ts.tv_sec;
1963         u = gmtime(&t);
1964         if (!u)
1965             rb_raise(rb_eArgError, "gmtime error");
1966         if (l->tm_year != u->tm_year)
1967             off = l->tm_year < u->tm_year ? -1 : 1;
1968         else if (l->tm_mon != u->tm_mon)
1969             off = l->tm_mon < u->tm_mon ? -1 : 1;
1970         else if (l->tm_mday != u->tm_mday)
1971             off = l->tm_mday < u->tm_mday ? -1 : 1;
1972         else
1973             off = 0;
1974         off = off * 24 + l->tm_hour - u->tm_hour;
1975         off = off * 60 + l->tm_min - u->tm_min;
1976         off = off * 60 + l->tm_sec - u->tm_sec;
1977         return LONG2FIX(off);
1978 #endif
1979     }
1980 }
1981
1982 /*
1983  *  call-seq:
1984  *     time.to_a => array
1985  *
1986  *  Returns a ten-element <i>array</i> of values for <i>time</i>:
1987  *  {<code>[ sec, min, hour, day, month, year, wday, yday, isdst, zone
1988  *  ]</code>}. See the individual methods for an explanation of the
1989  *  valid ranges of each value. The ten elements can be passed directly
1990  *  to <code>Time::utc</code> or <code>Time::local</code> to create a
1991  *  new <code>Time</code>.
1992  *
1993  *     t = Time.now     #=> 2007-11-19 08:36:01 -0600
1994  *     now = t.to_a     #=> [1, 36, 8, 19, 11, 2007, 1, 323, false, "CST"]
1995  */
1996
1997 static VALUE
1998 time_to_a(VALUE time)
1999 {
2000     struct time_object *tobj;
2001
2002     GetTimeval(time, tobj);
2003     if (tobj->tm_got == 0) {
2004         time_get_tm(time, tobj->gmt);
2005     }
2006     return rb_ary_new3(10,
2007                     INT2FIX(tobj->tm.tm_sec),
2008                     INT2FIX(tobj->tm.tm_min),
2009                     INT2FIX(tobj->tm.tm_hour),
2010                     INT2FIX(tobj->tm.tm_mday),
2011                     INT2FIX(tobj->tm.tm_mon+1),
2012                     LONG2NUM((long)tobj->tm.tm_year+1900),
2013                     INT2FIX(tobj->tm.tm_wday),
2014                     INT2FIX(tobj->tm.tm_yday+1),
2015                     tobj->tm.tm_isdst?Qtrue:Qfalse,
2016                     time_zone(time));
2017 }
2018
2019 #define SMALLBUF 100
2020 static int
2021 rb_strftime(char **buf, const char *format, struct tm *time)
2022 {
2023     int size, len, flen;
2024
2025     (*buf)[0] = '\0';
2026     flen = strlen(format);
2027     if (flen == 0) {
2028         return 0;
2029     }
2030     errno = 0;
2031     len = strftime(*buf, SMALLBUF, format, time);
2032     if (len != 0 || (**buf == '\0' && errno != ERANGE)) return len;
2033     for (size=1024; ; size*=2) {
2034         *buf = xmalloc(size);
2035         (*buf)[0] = '\0';
2036         len = strftime(*buf, size, format, time);
2037         /*
2038          * buflen can be zero EITHER because there's not enough
2039          * room in the string, or because the control command
2040          * goes to the empty string. Make a reasonable guess that
2041          * if the buffer is 1024 times bigger than the length of the
2042          * format string, it's not failing for lack of room.
2043          */
2044         if (len > 0 || size >= 1024 * flen) return len;
2045         xfree(*buf);
2046     }
2047     /* not reached */
2048 }
2049
2050 /*
2051  *  call-seq:
2052  *     time.strftime( string ) => string
2053  *
2054  *  Formats <i>time</i> according to the directives in the given format
2055  *  string. Any text not listed as a directive will be passed through
2056  *  to the output string.
2057  *
2058  *  Format meaning:
2059  *    %a - The abbreviated weekday name (``Sun'')
2060  *    %A - The  full  weekday  name (``Sunday'')
2061  *    %b - The abbreviated month name (``Jan'')
2062  *    %B - The  full  month  name (``January'')
2063  *    %c - The preferred local date and time representation
2064  *    %d - Day of the month (01..31)
2065  *    %H - Hour of the day, 24-hour clock (00..23)
2066  *    %I - Hour of the day, 12-hour clock (01..12)
2067  *    %j - Day of the year (001..366)
2068  *    %m - Month of the year (01..12)
2069  *    %M - Minute of the hour (00..59)
2070  *    %p - Meridian indicator (``AM''  or  ``PM'')
2071  *    %S - Second of the minute (00..60)
2072  *    %U - Week  number  of the current year,
2073  *            starting with the first Sunday as the first
2074  *            day of the first week (00..53)
2075  *    %W - Week  number  of the current year,
2076  *            starting with the first Monday as the first
2077  *            day of the first week (00..53)
2078  *    %w - Day of the week (Sunday is 0, 0..6)
2079  *    %x - Preferred representation for the date alone, no time
2080  *    %X - Preferred representation for the time alone, no date
2081  *    %y - Year without a century (00..99)
2082  *    %Y - Year with century
2083  *    %Z - Time zone name
2084  *    %% - Literal ``%'' character
2085  *
2086  *     t = Time.now                        #=> 2007-11-19 08:37:48 -0600
2087  *     t.strftime("Printed on %m/%d/%Y")   #=> "Printed on 11/19/2007"
2088  *     t.strftime("at %I:%M%p")            #=> "at 08:37AM"
2089  */
2090
2091 static VALUE
2092 time_strftime(VALUE time, VALUE format)
2093 {
2094     void rb_enc_copy(VALUE, VALUE);
2095     struct time_object *tobj;
2096     char buffer[SMALLBUF], *buf = buffer;
2097     const char *fmt;
2098     long len;
2099     VALUE str;
2100
2101     GetTimeval(time, tobj);
2102     if (tobj->tm_got == 0) {
2103         time_get_tm(time, tobj->gmt);
2104     }
2105     StringValue(format);
2106     if (!rb_enc_str_asciicompat_p(format)) {
2107         rb_raise(rb_eArgError, "format should have ASCII compatible encoding");
2108     }
2109     format = rb_str_new4(format);
2110     fmt = RSTRING_PTR(format);
2111     len = RSTRING_LEN(format);
2112     if (len == 0) {
2113         rb_warning("strftime called with empty format string");
2114     }
2115     else if (strlen(fmt) < len) {
2116         /* Ruby string may contain \0's. */
2117         const char *p = fmt, *pe = fmt + len;
2118
2119         str = rb_str_new(0, 0);
2120         while (p < pe) {
2121             len = rb_strftime(&buf, p, &tobj->tm);
2122             rb_str_cat(str, buf, len);
2123             p += strlen(p);
2124             if (buf != buffer) {
2125                 xfree(buf);
2126                 buf = buffer;
2127             }
2128             for (fmt = p; p < pe && !*p; ++p);
2129             if (p > fmt) rb_str_cat(str, fmt, p - fmt);
2130         }
2131         return str;
2132     }
2133     else {
2134         len = rb_strftime(&buf, RSTRING_PTR(format), &tobj->tm);
2135     }
2136     str = rb_str_new(buf, len);
2137     if (buf != buffer) xfree(buf);
2138     rb_enc_copy(str, format);
2139     return str;
2140 }
2141
2142 /*
2143  * undocumented
2144  */
2145
2146 static VALUE
2147 time_mdump(VALUE time)
2148 {
2149     struct time_object *tobj;
2150     struct tm *tm;
2151     unsigned long p, s;
2152     char buf[8];
2153     time_t t;
2154     int nsec;
2155     int i;
2156     VALUE str;
2157
2158     GetTimeval(time, tobj);
2159
2160     t = tobj->ts.tv_sec;
2161     tm = gmtime(&t);
2162
2163     if ((tm->tm_year & 0xffff) != tm->tm_year)
2164         rb_raise(rb_eArgError, "year too big to marshal: %ld", (long)tm->tm_year);
2165
2166     p = 0x1UL        << 31 | /*  1 */
2167         tobj->gmt    << 30 | /*  1 */
2168         tm->tm_year  << 14 | /* 16 */
2169         tm->tm_mon   << 10 | /*  4 */
2170         tm->tm_mday  <<  5 | /*  5 */
2171         tm->tm_hour;         /*  5 */
2172     s = tm->tm_min   << 26 | /*  6 */
2173         tm->tm_sec   << 20 | /*  6 */
2174         tobj->ts.tv_nsec / 1000;    /* 20 */
2175     nsec = tobj->ts.tv_nsec % 1000;
2176
2177     for (i=0; i<4; i++) {
2178         buf[i] = p & 0xff;
2179         p = RSHIFT(p, 8);
2180     }
2181     for (i=4; i<8; i++) {
2182         buf[i] = s & 0xff;
2183         s = RSHIFT(s, 8);
2184     }
2185
2186     str = rb_str_new(buf, 8);
2187     rb_copy_generic_ivar(str, time);
2188     if (nsec) {
2189         /*
2190          * submicro is formatted in fixed-point packed BCD (without sign).
2191          * It represent digits under microsecond.
2192          * For nanosecond resolution, 3 digits (2 bytes) are used.
2193          * However it can be longer.
2194          * Extra digits are ignored for loading.
2195          */
2196         unsigned char buf[2];
2197         int len = sizeof(buf);
2198         buf[1] = (nsec % 10) << 4;
2199         nsec /= 10;
2200         buf[0] = nsec % 10;
2201         nsec /= 10;
2202         buf[0] |= (nsec % 10) << 4;
2203         if (buf[1] == 0)
2204             len = 1;
2205         rb_ivar_set(str, id_submicro, rb_str_new((char *)buf, len));
2206     }
2207     return str;
2208 }
2209
2210 /*
2211  * call-seq:
2212  *   time._dump   => string
2213  *
2214  * Dump _time_ for marshaling.
2215  */
2216
2217 static VALUE
2218 time_dump(int argc, VALUE *argv, VALUE time)
2219 {
2220     VALUE str;
2221
2222     rb_scan_args(argc, argv, "01", 0);
2223     str = time_mdump(time);
2224
2225     return str;
2226 }
2227
2228 /*
2229  * undocumented
2230  */
2231
2232 static VALUE
2233 time_mload(VALUE time, VALUE str)
2234 {
2235     struct time_object *tobj;
2236     unsigned long p, s;
2237     time_t sec;
2238     long usec;
2239     unsigned char *buf;
2240     struct tm tm;
2241     int i, gmt;
2242     long nsec;
2243     VALUE submicro;
2244
2245     time_modify(time);
2246
2247     submicro = rb_attr_get(str, id_submicro);
2248     if (submicro != Qnil) {
2249         st_delete(rb_generic_ivar_table(str), (st_data_t*)&id_submicro, 0);
2250     }
2251     rb_copy_generic_ivar(time, str);
2252
2253     StringValue(str);
2254     buf = (unsigned char *)RSTRING_PTR(str);
2255     if (RSTRING_LEN(str) != 8) {
2256         rb_raise(rb_eTypeError, "marshaled time format differ");
2257     }
2258
2259     p = s = 0;
2260     for (i=0; i<4; i++) {
2261         p |= buf[i]<<(8*i);
2262     }
2263     for (i=4; i<8; i++) {
2264         s |= buf[i]<<(8*(i-4));
2265     }
2266
2267     if ((p & (1UL<<31)) == 0) {
2268         gmt = 0;
2269         sec = p;
2270         usec = s;
2271         nsec = usec * 1000;
2272     }
2273     else {
2274         p &= ~(1UL<<31);
2275         gmt        = (p >> 30) & 0x1;
2276         tm.tm_year = (p >> 14) & 0xffff;
2277         tm.tm_mon  = (p >> 10) & 0xf;
2278         tm.tm_mday = (p >>  5) & 0x1f;
2279         tm.tm_hour =  p        & 0x1f;
2280         tm.tm_min  = (s >> 26) & 0x3f;
2281         tm.tm_sec  = (s >> 20) & 0x3f;
2282         tm.tm_isdst = 0;
2283
2284         sec = make_time_t(&tm, Qtrue);
2285         usec = (long)(s & 0xfffff);
2286         nsec = usec * 1000;
2287
2288         if (submicro != Qnil) {
2289             unsigned char *ptr;
2290             long len;
2291             int digit;
2292             ptr = (unsigned char*)StringValuePtr(submicro);
2293             len = RSTRING_LEN(submicro);
2294             if (0 < len) {
2295                 if (10 <= (digit = ptr[0] >> 4)) goto end_submicro;
2296                 nsec += digit * 100;
2297                 if (10 <= (digit = ptr[0] & 0xf)) goto end_submicro;
2298                 nsec += digit * 10;
2299             }
2300             if (1 < len) {
2301                 if (10 <= (digit = ptr[1] >> 4)) goto end_submicro;
2302                 nsec += digit;
2303             }
2304 end_submicro: ;
2305         }
2306     }
2307     time_overflow_p(&sec, &nsec);
2308
2309     GetTimeval(time, tobj);
2310     tobj->tm_got = 0;
2311     tobj->gmt = gmt;
2312     tobj->ts.tv_sec = sec;
2313     tobj->ts.tv_nsec = nsec;
2314
2315     return time;
2316 }
2317
2318 /*
2319  * call-seq:
2320  *   Time._load(string)   => time
2321  *
2322  * Unmarshal a dumped +Time+ object.
2323  */
2324
2325 static VALUE
2326 time_load(VALUE klass, VALUE str)
2327 {
2328     VALUE time = time_s_alloc(klass);
2329
2330     time_mload(time, str);
2331     return time;
2332 }
2333
2334 /*
2335  *  <code>Time</code> is an abstraction of dates and times. Time is
2336  *  stored internally as the number of seconds and nanoseconds since
2337  *  the <em>Epoch</em>, January 1, 1970 00:00 UTC. On some operating
2338  *  systems, this offset is allowed to be negative. Also see the
2339  *  library modules <code>Date</code>. The
2340  *  <code>Time</code> class treats GMT (Greenwich Mean Time) and UTC
2341  *  (Coordinated Universal Time)<em>[Yes, UTC really does stand for
2342  *  Coordinated Universal Time. There was a committee involved.]</em>
2343  *  as equivalent.  GMT is the older way of referring to these
2344  *  baseline times but persists in the names of calls on POSIX
2345  *  systems.
2346  *
2347  *  All times are stored with some number of nanoseconds. Be aware of
2348  *  this fact when comparing times with each other---times that are
2349  *  apparently equal when displayed may be different when compared.
2350  */
2351
2352 void
2353 Init_Time(void)
2354 {
2355 #undef rb_intern
2356 #define rb_intern(str) rb_intern_const(str)
2357
2358     id_divmod = rb_intern("divmod");
2359     id_mul = rb_intern("*");
2360     id_submicro = rb_intern("submicro");
2361
2362     rb_cTime = rb_define_class("Time", rb_cObject);
2363     rb_include_module(rb_cTime, rb_mComparable);
2364
2365     rb_define_alloc_func(rb_cTime, time_s_alloc);
2366     rb_define_singleton_method(rb_cTime, "now", rb_class_new_instance, -1);
2367     rb_define_singleton_method(rb_cTime, "at", time_s_at, -1);
2368     rb_define_singleton_method(rb_cTime, "utc", time_s_mkutc, -1);
2369     rb_define_singleton_method(rb_cTime, "gm", time_s_mkutc, -1);
2370     rb_define_singleton_method(rb_cTime, "local", time_s_mktime, -1);
2371     rb_define_singleton_method(rb_cTime, "mktime", time_s_mktime, -1);
2372
2373     rb_define_method(rb_cTime, "to_i", time_to_i, 0);
2374     rb_define_method(rb_cTime, "to_f", time_to_f, 0);
2375     rb_define_method(rb_cTime, "<=>", time_cmp, 1);
2376     rb_define_method(rb_cTime, "eql?", time_eql, 1);
2377     rb_define_method(rb_cTime, "hash", time_hash, 0);
2378     rb_define_method(rb_cTime, "initialize", time_init, 0);
2379     rb_define_method(rb_cTime, "initialize_copy", time_init_copy, 1);
2380
2381     rb_define_method(rb_cTime, "localtime", time_localtime, 0);
2382     rb_define_method(rb_cTime, "gmtime", time_gmtime, 0);
2383     rb_define_method(rb_cTime, "utc", time_gmtime, 0);
2384     rb_define_method(rb_cTime, "getlocal", time_getlocaltime, 0);
2385     rb_define_method(rb_cTime, "getgm", time_getgmtime, 0);
2386     rb_define_method(rb_cTime, "getutc", time_getgmtime, 0);
2387
2388     rb_define_method(rb_cTime, "ctime", time_asctime, 0);
2389     rb_define_method(rb_cTime, "asctime", time_asctime, 0);
2390     rb_define_method(rb_cTime, "to_s", time_to_s, 0);
2391     rb_define_method(rb_cTime, "inspect", time_to_s, 0);
2392     rb_define_method(rb_cTime, "to_a", time_to_a, 0);
2393
2394     rb_define_method(rb_cTime, "+", time_plus, 1);
2395     rb_define_method(rb_cTime, "-", time_minus, 1);
2396
2397     rb_define_method(rb_cTime, "succ", time_succ, 0);
2398     rb_define_method(rb_cTime, "sec", time_sec, 0);
2399     rb_define_method(rb_cTime, "min", time_min, 0);
2400     rb_define_method(rb_cTime, "hour", time_hour, 0);
2401     rb_define_method(rb_cTime, "mday", time_mday, 0);
2402     rb_define_method(rb_cTime, "day", time_mday, 0);
2403     rb_define_method(rb_cTime, "mon", time_mon, 0);
2404     rb_define_method(rb_cTime, "month", time_mon, 0);
2405     rb_define_method(rb_cTime, "year", time_year, 0);
2406     rb_define_method(rb_cTime, "wday", time_wday, 0);
2407     rb_define_method(rb_cTime, "yday", time_yday, 0);
2408     rb_define_method(rb_cTime, "isdst", time_isdst, 0);
2409     rb_define_method(rb_cTime, "dst?", time_isdst, 0);
2410     rb_define_method(rb_cTime, "zone", time_zone, 0);
2411     rb_define_method(rb_cTime, "gmtoff", time_utc_offset, 0);
2412     rb_define_method(rb_cTime, "gmt_offset", time_utc_offset, 0);
2413     rb_define_method(rb_cTime, "utc_offset", time_utc_offset, 0);
2414
2415     rb_define_method(rb_cTime, "utc?", time_utc_p, 0);
2416     rb_define_method(rb_cTime, "gmt?", time_utc_p, 0);
2417
2418     rb_define_method(rb_cTime, "sunday?", time_sunday, 0);
2419     rb_define_method(rb_cTime, "monday?", time_monday, 0);
2420     rb_define_method(rb_cTime, "tuesday?", time_tuesday, 0);
2421     rb_define_method(rb_cTime, "wednesday?", time_wednesday, 0);
2422     rb_define_method(rb_cTime, "thursday?", time_thursday, 0);
2423     rb_define_method(rb_cTime, "friday?", time_friday, 0);
2424     rb_define_method(rb_cTime, "saturday?", time_saturday, 0);
2425
2426     rb_define_method(rb_cTime, "tv_sec", time_to_i, 0);
2427     rb_define_method(rb_cTime, "tv_usec", time_usec, 0);
2428     rb_define_method(rb_cTime, "usec", time_usec, 0);
2429     rb_define_method(rb_cTime, "tv_nsec", time_nsec, 0);
2430     rb_define_method(rb_cTime, "nsec", time_nsec, 0);
2431
2432     rb_define_method(rb_cTime, "strftime", time_strftime, 1);
2433
2434     /* methods for marshaling */
2435     rb_define_method(rb_cTime, "_dump", time_dump, -1);
2436     rb_define_singleton_method(rb_cTime, "_load", time_load, 1);
2437 #if 0
2438     /* Time will support marshal_dump and marshal_load in the future (1.9 maybe) */
2439     rb_define_method(rb_cTime, "marshal_dump", time_mdump, 0);
2440     rb_define_method(rb_cTime, "marshal_load", time_mload, 1);
2441 #endif
2442 }