time.c

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/**********************************************************************

  time.c -

  $Author: nobu $
  $Date: 2005/10/22 04:27:48 $
  created at: Tue Dec 28 14:31:59 JST 1993

  Copyright (C) 1993-2003 Yukihiro Matsumoto

**********************************************************************/

#include "ruby.h"
#include <sys/types.h>
#include <time.h>

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#include <math.h>

VALUE rb_cTime;

struct time_object {
    struct timeval tv;
    struct tm tm;
    int gmt;
    int tm_got;
};

#define GetTimeval(obj, tobj) \
    Data_Get_Struct(obj, struct time_object, tobj)

static void time_free (void *);

static void
time_free(tobj)
    void *tobj;
{
    if (tobj) free(tobj);
}

static VALUE time_s_alloc (VALUE);
static VALUE
time_s_alloc(klass)
    VALUE klass;
{
    VALUE obj;
    struct time_object *tobj;

    obj = Data_Make_Struct(klass, struct time_object, 0, time_free, tobj);
    tobj->tm_got=0;
    tobj->tv.tv_sec = 0;
    tobj->tv.tv_usec = 0;

    return obj;
}

static void
time_modify(time)
    VALUE time;
{
    rb_check_frozen(time);
    if (!OBJ_TAINTED(time) && rb_safe_level() >= 4)
        rb_raise(rb_eSecurityError, "Insecure: can't modify Time");
}

/*
 *  Document-method: now
 *
 *  Synonym for <code>Time.new</code>. Returns a +Time+ object
 *  initialized tot he current system time.
 *
 *  call-seq:
 *     Time.new -> time
 *  
 *  Returns a <code>Time</code> object initialized to the current system
 *  time. <b>Note:</b> The object created will be created using the
 *  resolution available on your system clock, and so may include
 *  fractional seconds.
 *     
 *     a = Time.new      #=> Wed Apr 09 08:56:03 CDT 2003
 *     b = Time.new      #=> Wed Apr 09 08:56:03 CDT 2003
 *     a == b            #=> false
 *     "%.6f" % a.to_f   #=> "1049896563.230740"
 *     "%.6f" % b.to_f   #=> "1049896563.231466"
 *     
 */

static VALUE
time_init(time)
    VALUE time;
{
    struct time_object *tobj;

    time_modify(time);
    GetTimeval(time, tobj);
    tobj->tm_got=0;
    tobj->tv.tv_sec = 0;
    tobj->tv.tv_usec = 0;
    if (gettimeofday(&tobj->tv, 0) < 0) {
        rb_sys_fail("gettimeofday");
    }

    return time;
}

#define NDIV(x,y) (-(-((x)+1)/(y))-1)
#define NMOD(x,y) ((y)-(-((x)+1)%(y))-1)

static void
time_overflow_p(secp, usecp)
    time_t *secp, *usecp;
{
    time_t tmp, sec = *secp, usec = *usecp;

    if (usec >= 1000000) {      /* usec positive overflow */
        tmp = sec + usec / 1000000;
        usec %= 1000000;
        if (sec > 0 && tmp < 0) {
            rb_raise(rb_eRangeError, "out of Time range");
        }
        sec = tmp;
    }
    if (usec < 0) {             /* usec negative overflow */
        tmp = sec + NDIV(usec,1000000); /* negative div */
        usec = NMOD(usec,1000000);      /* negative mod */
        if (sec < 0 && tmp > 0) {
            rb_raise(rb_eRangeError, "out of Time range");
        }
        sec = tmp;
    }
#ifndef NEGATIVE_TIME_T
    if (sec < 0 || (sec == 0 && usec < 0))
        rb_raise(rb_eArgError, "time must be positive");
#endif
    *secp = sec;
    *usecp = usec;
}

static VALUE
time_new_internal(klass, sec, usec)
    VALUE klass;
    time_t sec, usec;
{
    VALUE time = time_s_alloc(klass);
    struct time_object *tobj;

    GetTimeval(time, tobj);
    time_overflow_p(&sec, &usec);
    tobj->tv.tv_sec = sec;
    tobj->tv.tv_usec = usec;

    return time;
}

VALUE
rb_time_new(sec, usec)
    time_t sec, usec;
{
    return time_new_internal(rb_cTime, sec, usec);
}

static struct timeval
time_timeval(time, interval)
    VALUE time;
    int interval;
{
    struct timeval t;
    char *tstr = interval ? "time interval" : "time";

#ifndef NEGATIVE_TIME_T
    interval = 1;
#endif

    switch (TYPE(time)) {
      case T_FIXNUM:
        t.tv_sec = FIX2LONG(time);
        if (interval && t.tv_sec < 0)
            rb_raise(rb_eArgError, "%s must be positive", tstr);
        t.tv_usec = 0;
        break;

      case T_FLOAT:
        if (interval && RFLOAT(time)->value < 0.0)
            rb_raise(rb_eArgError, "%s must be positive", tstr);
        else {
            double f, d;

            d = modf(RFLOAT(time)->value, &f);
            t.tv_sec = (time_t)f;
            if (f != t.tv_sec) {
                rb_raise(rb_eRangeError, "%f out of Time range", RFLOAT(time)->value);
            }
            t.tv_usec = (time_t)(d*1e6);
        }
        break;

      case T_BIGNUM:
        t.tv_sec = NUM2LONG(time);
        if (interval && t.tv_sec < 0)
            rb_raise(rb_eArgError, "%s must be positive", tstr);
        t.tv_usec = 0;
        break;

      default:
        rb_raise(rb_eTypeError, "can't convert %s into %s",
                 rb_obj_classname(time), tstr);
        break;
    }
    return t;
}

struct timeval
rb_time_interval(time)
    VALUE time;
{
    return time_timeval(time, Qtrue);
}

struct timeval
rb_time_timeval(time)
    VALUE time;
{
    struct time_object *tobj;
    struct timeval t;

    if (TYPE(time) == T_DATA && RDATA(time)->dfree == time_free) {
        GetTimeval(time, tobj);
        t = tobj->tv;
        return t;
    }
    return time_timeval(time, Qfalse);
}

/*
 *  call-seq:
 *     Time.at( aTime ) => time
 *     Time.at( seconds [, microseconds] ) => time
 *  
 *  Creates a new time object with the value given by <i>aTime</i>, or
 *  the given number of <i>seconds</i> (and optional
 *  <i>microseconds</i>) from epoch. A non-portable feature allows the
 *  offset to be negative on some systems.
 *     
 *     Time.at(0)            #=> Wed Dec 31 18:00:00 CST 1969
 *     Time.at(946702800)    #=> Fri Dec 31 23:00:00 CST 1999
 *     Time.at(-284061600)   #=> Sat Dec 31 00:00:00 CST 1960
 */

static VALUE
time_s_at(argc, argv, klass)
    int argc;
    VALUE *argv;
    VALUE klass;
{
    struct timeval tv;
    VALUE time, t;

    if (rb_scan_args(argc, argv, "11", &time, &t) == 2) {
        tv.tv_sec = NUM2LONG(time);
        tv.tv_usec = NUM2LONG(t);
    }
    else {
        tv = rb_time_timeval(time);
    }
    t = time_new_internal(klass, tv.tv_sec, tv.tv_usec);
    if (TYPE(time) == T_DATA && RDATA(time)->dfree == time_free) {
        struct time_object *tobj, *tobj2;

        GetTimeval(time, tobj);
        GetTimeval(t, tobj2);
        tobj2->gmt = tobj->gmt;
    }
    return t;
}

static char *months [12] = {
    "jan", "feb", "mar", "apr", "may", "jun",
    "jul", "aug", "sep", "oct", "nov", "dec",
};

static long
obj2long(obj)
    VALUE obj;
{
    if (TYPE(obj) == T_STRING) {
        obj = rb_str_to_inum(obj, 10, Qfalse);
    }

    return NUM2LONG(obj);
}

static void
time_arg(argc, argv, tm, usec)
    int argc;
    VALUE *argv;
    struct tm *tm;
    time_t *usec;
{
    VALUE v[8];
    int i;
    long year;

    MEMZERO(tm, struct tm, 1);
    *usec = 0;
    if (argc == 10) {
        v[0] = argv[5];
        v[1] = argv[4];
        v[2] = argv[3];
        v[3] = argv[2];
        v[4] = argv[1];
        v[5] = argv[0];
        v[6] = Qnil;
        tm->tm_isdst = RTEST(argv[8]) ? 1 : 0;
    }
    else {
        rb_scan_args(argc, argv, "17", &v[0],&v[1],&v[2],&v[3],&v[4],&v[5],&v[6],&v[7]);
        /* v[6] may be usec or zone (parsedate) */
        /* v[7] is wday (parsedate; ignored) */
        tm->tm_wday = -1;
        tm->tm_isdst = -1;
    }

    year = obj2long(v[0]);

    if (0 <= year && year < 39) {
        year += 100;
        rb_warning("2 digits year is used");
    }
    else if (69 <= year && year < 139) {
        rb_warning("2 or 3 digits year is used");
    }
    else {
        year -= 1900;
    }

    tm->tm_year = year;

    if (NIL_P(v[1])) {
        tm->tm_mon = 0;
    }
    else {
        VALUE s = rb_check_string_type(v[1]);
        if (!NIL_P(s)) {
            tm->tm_mon = -1;
            for (i=0; i<12; i++) {
                if (RSTRING(s)->len == 3 &&
                    strcasecmp(months[i], RSTRING(v[1])->ptr) == 0) {
                    tm->tm_mon = i;
                    break;
                }
            }
            if (tm->tm_mon == -1) {
                char c = RSTRING(s)->ptr[0];

                if ('0' <= c && c <= '9') {
                    tm->tm_mon = obj2long(s)-1;
                }
            }
        }
        else {
            tm->tm_mon = obj2long(v[1])-1;
        }
    }
    if (NIL_P(v[2])) {
        tm->tm_mday = 1;
    }
    else {
        tm->tm_mday = obj2long(v[2]);
    }
    tm->tm_hour = NIL_P(v[3])?0:obj2long(v[3]);
    tm->tm_min  = NIL_P(v[4])?0:obj2long(v[4]);
    tm->tm_sec  = NIL_P(v[5])?0:obj2long(v[5]);
    if (!NIL_P(v[6])) {
        if (argc == 8) {
            /* v[6] is timezone, but ignored */
        }
        else if (argc == 7) {
            *usec = obj2long(v[6]);
        }
    }

    /* value validation */
    if (
           tm->tm_year != year ||
#ifndef NEGATIVE_TIME_T
           tm->tm_year < 69 ||
#endif
           tm->tm_mon  < 0 || tm->tm_mon  > 11
        || tm->tm_mday < 1 || tm->tm_mday > 31
        || tm->tm_hour < 0 || tm->tm_hour > 23
        || tm->tm_min  < 0 || tm->tm_min  > 59
        || tm->tm_sec  < 0 || tm->tm_sec  > 60)
        rb_raise(rb_eArgError, "argument out of range");
}

static VALUE time_gmtime (VALUE);
static VALUE time_localtime (VALUE);
static VALUE time_get_tm (VALUE, int);

static int
leap_year_p(y)
    long y;
{
  return ((y % 4 == 0) && (y % 100 != 0)) || (y % 400 == 0);
}

#define DIV(n,d) ((n)<0 ? NDIV((n),(d)) : (n)/(d))

static time_t
timegm_noleapsecond(tm)
    struct tm *tm;
{
    static int common_year_yday_offset[] = {
        -1,
        -1 + 31,
        -1 + 31 + 28,
        -1 + 31 + 28 + 31,
        -1 + 31 + 28 + 31 + 30,
        -1 + 31 + 28 + 31 + 30 + 31,
        -1 + 31 + 28 + 31 + 30 + 31 + 30,
        -1 + 31 + 28 + 31 + 30 + 31 + 30 + 31,
        -1 + 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31,
        -1 + 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30,
        -1 + 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31,
        -1 + 31 + 28 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30
          /* 1    2    3    4    5    6    7    8    9    10   11 */
    };
    static int leap_year_yday_offset[] = {
        -1,
        -1 + 31,
        -1 + 31 + 29,
        -1 + 31 + 29 + 31,
        -1 + 31 + 29 + 31 + 30,
        -1 + 31 + 29 + 31 + 30 + 31,
        -1 + 31 + 29 + 31 + 30 + 31 + 30,
        -1 + 31 + 29 + 31 + 30 + 31 + 30 + 31,
        -1 + 31 + 29 + 31 + 30 + 31 + 30 + 31 + 31,
        -1 + 31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30,
        -1 + 31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31,
        -1 + 31 + 29 + 31 + 30 + 31 + 30 + 31 + 31 + 30 + 31 + 30
          /* 1    2    3    4    5    6    7    8    9    10   11 */
    };

    long tm_year = tm->tm_year;
    int tm_yday = tm->tm_mday;
    if (leap_year_p(tm_year + 1900))
        tm_yday += leap_year_yday_offset[tm->tm_mon];
    else
        tm_yday += common_year_yday_offset[tm->tm_mon];

    /*
     *  `Seconds Since the Epoch' in SUSv3:
     *  tm_sec + tm_min*60 + tm_hour*3600 + tm_yday*86400 +
     *  (tm_year-70)*31536000 + ((tm_year-69)/4)*86400 -
     *  ((tm_year-1)/100)*86400 + ((tm_year+299)/400)*86400
     */
    return tm->tm_sec + tm->tm_min*60 + tm->tm_hour*3600 +
           (time_t)(tm_yday +
                    (tm_year-70)*365 +
                    DIV(tm_year-69,4) -
                    DIV(tm_year-1,100) +
                    DIV(tm_year+299,400))*86400;
}

static int
tmcmp(a, b)
    struct tm *a;
    struct tm *b;
{
    if (a->tm_year != b->tm_year)
        return a->tm_year < b->tm_year ? -1 : 1;
    else if (a->tm_mon != b->tm_mon)
        return a->tm_mon < b->tm_mon ? -1 : 1;
    else if (a->tm_mday != b->tm_mday)
        return a->tm_mday < b->tm_mday ? -1 : 1;
    else if (a->tm_hour != b->tm_hour)
        return a->tm_hour < b->tm_hour ? -1 : 1;
    else if (a->tm_min != b->tm_min)
        return a->tm_min < b->tm_min ? -1 : 1;
    else if (a->tm_sec != b->tm_sec)
        return a->tm_sec < b->tm_sec ? -1 : 1;
    else
        return 0;
}

static time_t
search_time_t(tptr, utc_p)
    struct tm *tptr;
    int utc_p;
{
    time_t guess, guess_lo, guess_hi;
    struct tm *tm, tm_lo, tm_hi;
    int d, have_guess;
    int find_dst;

    find_dst = 0 < tptr->tm_isdst;

#ifdef NEGATIVE_TIME_T
    guess_lo = 1L << (8 * sizeof(time_t) - 1);
#else
    guess_lo = 0;
#endif
    guess_hi = ((time_t)-1) < ((time_t)0) ?
               (1UL << (8 * sizeof(time_t) - 1)) - 1 :
               ~(time_t)0;

    guess = timegm_noleapsecond(tptr);
    tm = (utc_p ? gmtime : localtime)(&guess);
    if (tm) {
        d = tmcmp(tptr, tm);
        if (d == 0) return guess;
        if (d < 0) {
            guess_hi = guess;
            guess -= 24 * 60 * 60;
        }
        else {
            guess_lo = guess;
            guess += 24 * 60 * 60;
        }
        if (guess_lo < guess && guess < guess_hi &&
            (tm = (utc_p ? gmtime : localtime)(&guess)) != NULL) {
            d = tmcmp(tptr, tm);
            if (d == 0) return guess;
            if (d < 0)
                guess_hi = guess;
            else
                guess_lo = guess;
        }
    }

    tm = (utc_p ? gmtime : localtime)(&guess_lo);
    if (!tm) goto error;
    d = tmcmp(tptr, tm);
    if (d < 0) goto out_of_range;
    if (d == 0) return guess_lo;
    tm_lo = *tm;

    tm = (utc_p ? gmtime : localtime)(&guess_hi);
    if (!tm) goto error;
    d = tmcmp(tptr, tm);
    if (d > 0) goto out_of_range;
    if (d == 0) return guess_hi;
    tm_hi = *tm;

    have_guess = 0;

    while (guess_lo + 1 < guess_hi) {
      /* there is a gap between guess_lo and guess_hi. */
      unsigned long range = 0;
      if (!have_guess) {
        int a, b;
        /*
          Try precious guess by a linear interpolation at first.
          `a' and `b' is a coefficient of guess_lo and guess_hi as:

            guess = (guess_lo * a + guess_hi * b) / (a + b)

          However this causes overflow in most cases, following assignment
          is used instead:

            guess = guess_lo / d * a + (guess_lo % d) * a / d
                  + guess_hi / d * b + (guess_hi % d) * b / d
              where d = a + b

          To avoid overflow in this assignment, `d' is restricted to less than
          sqrt(2**31).  By this restriction and other reasons, the guess is
          not accurate and some error is expected.  `range' approximates 
          the maximum error.

          When these parameters are not suitable, i.e. guess is not within
          guess_lo and guess_hi, simple guess by binary search is used.
        */
        range = 366 * 24 * 60 * 60;
        a = (tm_hi.tm_year - tptr->tm_year);
        b = (tptr->tm_year - tm_lo.tm_year);
        /* 46000 is selected as `some big number less than sqrt(2**31)'. */
        if (a + b <= 46000 / 12) {
          range = 31 * 24 * 60 * 60;
          a *= 12;
          b *= 12;
          a += tm_hi.tm_mon - tptr->tm_mon;
          b += tptr->tm_mon - tm_lo.tm_mon;
          if (a + b <= 46000 / 31) {
            range = 24 * 60 * 60;
            a *= 31;
            b *= 31;
            a += tm_hi.tm_mday - tptr->tm_mday;
            b += tptr->tm_mday - tm_lo.tm_mday;
            if (a + b <= 46000 / 24) {
              range = 60 * 60;
              a *= 24;
              b *= 24;
              a += tm_hi.tm_hour - tptr->tm_hour;
              b += tptr->tm_hour - tm_lo.tm_hour;
              if (a + b <= 46000 / 60) {
                range = 60;
                a *= 60;
                b *= 60;
                a += tm_hi.tm_min - tptr->tm_min;
                b += tptr->tm_min - tm_lo.tm_min;
                if (a + b <= 46000 / 60) {
                  range = 1;
                  a *= 60;
                  b *= 60;
                  a += tm_hi.tm_sec - tptr->tm_sec;
                  b += tptr->tm_sec - tm_lo.tm_sec;
                }
              }
            }
          }
        }
        if (a <= 0) a = 1;
        if (b <= 0) b = 1;
        d = a + b;
        /*
          Although `/' and `%' may produce unexpected result with negative
          argument, it doesn't cause serious problem because there is a
          fail safe.
        */
        guess = guess_lo / d * a + (guess_lo % d) * a / d
              + guess_hi / d * b + (guess_hi % d) * b / d;
        have_guess = 1;
      }

      if (guess <= guess_lo || guess_hi <= guess) {
        /* Precious guess is invalid. try binary search. */ 
        guess = guess_lo / 2 + guess_hi / 2;
        if (guess <= guess_lo)
          guess = guess_lo + 1;
        else if (guess >= guess_hi)
          guess = guess_hi - 1;
        range = 0;
      }

      tm = (utc_p ? gmtime : localtime)(&guess);
      if (!tm) goto error;
      have_guess = 0;

      d = tmcmp(tptr, tm);
      if (d < 0) {
        guess_hi = guess;
        tm_hi = *tm;
        if (range) {
          guess = guess - range;
          range = 0;
          if (guess_lo < guess && guess < guess_hi)
            have_guess = 1;
        }
      }
      else if (d > 0) {
        guess_lo = guess;
        tm_lo = *tm;
        if (range) {
          guess = guess + range;
          range = 0;
          if (guess_lo < guess && guess < guess_hi)
            have_guess = 1;
        }
      }
      else {
        if (!utc_p) {
          /* If localtime is nonmonotonic, another result may exist. */
          time_t guess2;
          if (find_dst) {
            guess2 = guess - 2 * 60 * 60;
            tm = localtime(&guess2);
            if (tm) {
              if (tptr->tm_hour != (tm->tm_hour + 2) % 24 ||
                  tptr->tm_min != tm->tm_min ||
                  tptr->tm_sec != tm->tm_sec) {
                guess2 -= (tm->tm_hour - tptr->tm_hour) * 60 * 60 +
                          (tm->tm_min - tptr->tm_min) * 60 +
                          (tm->tm_sec - tptr->tm_sec);
                if (tptr->tm_mday != tm->tm_mday)
                  guess2 += 24 * 60 * 60;
                if (guess != guess2) {
                  tm = localtime(&guess2);
                  if (tmcmp(tptr, tm) == 0) {
                    if (guess < guess2)
                      return guess;
                    else
                      return guess2;
                  }
                }
              }
            }
          }
          else {
            guess2 = guess + 2 * 60 * 60;
            tm = localtime(&guess2);
            if (tm) {
              if ((tptr->tm_hour + 2) % 24 != tm->tm_hour ||
                  tptr->tm_min != tm->tm_min ||
                  tptr->tm_sec != tm->tm_sec) {
                guess2 -= (tm->tm_hour - tptr->tm_hour) * 60 * 60 +
                          (tm->tm_min - tptr->tm_min) * 60 +
                          (tm->tm_sec - tptr->tm_sec);
                if (tptr->tm_mday != tm->tm_mday)
                  guess2 -= 24 * 60 * 60;
                if (guess != guess2) {
                  tm = localtime(&guess2);
                  if (tmcmp(tptr, tm) == 0) {
                    if (guess < guess2)
                      return guess2;
                    else
                      return guess;
                  }
                }
              }
            }
          }
        }
        return guess;
      }
    }
    /* Given argument has no corresponding time_t. Let's outerpolation. */
    if (tm_lo.tm_year == tptr->tm_year && tm_lo.tm_mon == tptr->tm_mon) {
      return guess_lo +
        (tptr->tm_mday - tm_lo.tm_mday) * 24 * 60 * 60 +
        (tptr->tm_hour - tm_lo.tm_hour) * 60 * 60 +
        (tptr->tm_min - tm_lo.tm_min) * 60 +
        (tptr->tm_sec - tm_lo.tm_sec);
    }
    else if (tm_hi.tm_year == tptr->tm_year && tm_hi.tm_mon == tptr->tm_mon) {
      return guess_hi +
        (tptr->tm_mday - tm_hi.tm_mday) * 24 * 60 * 60 +
        (tptr->tm_hour - tm_hi.tm_hour) * 60 * 60 +
        (tptr->tm_min - tm_hi.tm_min) * 60 +
        (tptr->tm_sec - tm_hi.tm_sec);
    }

  out_of_range:
    rb_raise(rb_eArgError, "time out of range");

  error:
    rb_raise(rb_eArgError, "gmtime/localtime error");
    return 0;                   /* not reached */
}

static time_t
make_time_t(tptr, utc_p)
    struct tm *tptr;
    int utc_p;
{
    time_t t;
    struct tm *tmp, buf;
    buf = *tptr;
    if (utc_p) {
#if defined(HAVE_TIMEGM)
        if ((t = timegm(&buf)) != -1)
            return t;
#ifdef NEGATIVE_TIME_T
        if ((tmp = gmtime(&t)) &&
            tptr->tm_year == tmp->tm_year &&
            tptr->tm_mon == tmp->tm_mon &&
            tptr->tm_mday == tmp->tm_mday &&
            tptr->tm_hour == tmp->tm_hour &&
            tptr->tm_min == tmp->tm_min &&
            tptr->tm_sec == tmp->tm_sec)
            return t;
#endif
#endif
        return search_time_t(&buf, utc_p);
    }
    else {
#if defined(HAVE_MKTIME)
        if ((t = mktime(&buf)) != -1)
            return t;
#ifdef NEGATIVE_TIME_T
        if ((tmp = localtime(&t)) &&
            tptr->tm_year == tmp->tm_year &&
            tptr->tm_mon == tmp->tm_mon &&
            tptr->tm_mday == tmp->tm_mday &&
            tptr->tm_hour == tmp->tm_hour &&
            tptr->tm_min == tmp->tm_min &&
            tptr->tm_sec == tmp->tm_sec)
            return t;
#endif
#endif
        return search_time_t(&buf, utc_p);
    }
}

static VALUE
time_utc_or_local(argc, argv, utc_p, klass)
    int argc;
    VALUE *argv;
    int utc_p;
    VALUE klass;
{
    struct tm tm;
    VALUE time;
    time_t usec;

    time_arg(argc, argv, &tm, &usec);
    time = time_new_internal(klass, make_time_t(&tm, utc_p), usec);
    if (utc_p) return time_gmtime(time);
    return time_localtime(time);
}

/*
 *  call-seq:
 *     Time.utc( year [, month, day, hour, min, sec, usec] ) => time
 *     Time.utc( sec, min, hour, day, month, year, wday, yday, isdst, tz
 *     ) => time
 *     Time.gm( year [, month, day, hour, min, sec, usec] ) => time
 *     Time.gm( sec, min, hour, day, month, year, wday, yday, isdst, tz
 *     ) => time
 *     
 *  Creates a time based on given values, interpreted as UTC (GMT). The
 *  year must be specified. Other values default to the minimum value
 *  for that field (and may be <code>nil</code> or omitted). Months may
 *  be specified by numbers from 1 to 12, or by the three-letter English
 *  month names. Hours are specified on a 24-hour clock (0..23). Raises
 *  an <code>ArgumentError</code> if any values are out of range. Will
 *  also accept ten arguments in the order output by
 *  <code>Time#to_a</code>.
 *
 *     Time.utc(2000,"jan",1,20,15,1)  #=> Sat Jan 01 20:15:01 UTC 2000
 *     Time.gm(2000,"jan",1,20,15,1)   #=> Sat Jan 01 20:15:01 UTC 2000
 */
static VALUE
time_s_mkutc(argc, argv, klass)
    int argc;
    VALUE *argv;
    VALUE klass;
{
    return time_utc_or_local(argc, argv, Qtrue, klass);
}

/*
 *  call-seq:
 *     Time.local( year [, month, day, hour, min, sec, usec] ) => time
 *     Time.local( sec, min, hour, day, month, year, wday, yday, isdst,
 *     tz ) => time
 *     Time.mktime( year, month, day, hour, min, sec, usec )   => time
 *  
 *  Same as <code>Time::gm</code>, but interprets the values in the
 *  local time zone.
 *     
 *     Time.local(2000,"jan",1,20,15,1)   #=> Sat Jan 01 20:15:01 CST 2000
 */

static VALUE
time_s_mktime(argc, argv, klass)
    int argc;
    VALUE *argv;
    VALUE klass;
{
    return time_utc_or_local(argc, argv, Qfalse, klass);
}

/*
 *  call-seq:
 *     time.to_i   => int
 *     time.tv_sec => int
 *  
 *  Returns the value of <i>time</i> as an integer number of seconds
 *  since epoch.
 *     
 *     t = Time.now
 *     "%10.5f" % t.to_f   #=> "1049896564.17839"
 *     t.to_i              #=> 1049896564
 */

static VALUE
time_to_i(time)
    VALUE time;
{
    struct time_object *tobj;

    GetTimeval(time, tobj);
    return LONG2NUM(tobj->tv.tv_sec);
}

/*
 *  call-seq:
 *     time.to_f => float
 *  
 *  Returns the value of <i>time</i> as a floating point number of
 *  seconds since epoch.
 *     
 *     t = Time.now
 *     "%10.5f" % t.to_f   #=> "1049896564.13654"
 *     t.to_i              #=> 1049896564
 */

static VALUE
time_to_f(time)
    VALUE time;
{
    struct time_object *tobj;

    GetTimeval(time, tobj);
    return rb_float_new((double)tobj->tv.tv_sec+(double)tobj->tv.tv_usec/1e6);
}

/*
 *  call-seq:
 *     time.usec    => int
 *     time.tv_usec => int
 *  
 *  Returns just the number of microseconds for <i>time</i>.
 *     
 *     t = Time.now        #=> Wed Apr 09 08:56:04 CDT 2003
 *     "%10.6f" % t.to_f   #=> "1049896564.259970"
 *     t.usec              #=> 259970
 */

static VALUE
time_usec(time)
    VALUE time;
{
    struct time_object *tobj;

    GetTimeval(time, tobj);
    return LONG2NUM(tobj->tv.tv_usec);
}

/*
 *  call-seq:
 *     time <=> other_time => -1, 0, +1 
 *     time <=> numeric    => -1, 0, +1
 *  
 *  Comparison---Compares <i>time</i> with <i>other_time</i> or with
 *  <i>numeric</i>, which is the number of seconds (possibly
 *  fractional) since epoch.
 *     
 *     t = Time.now       #=> Wed Apr 09 08:56:03 CDT 2003
 *     t2 = t + 2592000   #=> Fri May 09 08:56:03 CDT 2003
 *     t <=> t2           #=> -1
 *     t2 <=> t           #=> 1
 *     t <=> t            #=> 0
 */

static VALUE
time_cmp(time1, time2)
    VALUE time1, time2;
{
    struct time_object *tobj1, *tobj2;

    GetTimeval(time1, tobj1);
    if (TYPE(time2) == T_DATA && RDATA(time2)->dfree == time_free) {
        GetTimeval(time2, tobj2);
        if (tobj1->tv.tv_sec == tobj2->tv.tv_sec) {
            if (tobj1->tv.tv_usec == tobj2->tv.tv_usec) return INT2FIX(0);
            if (tobj1->tv.tv_usec > tobj2->tv.tv_usec) return INT2FIX(1);
            return INT2FIX(-1);
        }
        if (tobj1->tv.tv_sec > tobj2->tv.tv_sec) return INT2FIX(1);
        return INT2FIX(-1);
    }

    return Qnil;
}

/*
 * call-seq:
 *  time.eql?(other_time)
 *
 * Return <code>true</code> if <i>time</i> and <i>other_time</i> are
 * both <code>Time</code> objects with the same seconds and fractional
 * seconds.
 */

static VALUE
time_eql(time1, time2)
    VALUE time1, time2;
{
    struct time_object *tobj1, *tobj2;

    GetTimeval(time1, tobj1);
    if (TYPE(time2) == T_DATA && RDATA(time2)->dfree == time_free) {
        GetTimeval(time2, tobj2);
        if (tobj1->tv.tv_sec == tobj2->tv.tv_sec) {
            if (tobj1->tv.tv_usec == tobj2->tv.tv_usec) return Qtrue;
        }
    }
    return Qfalse;
}

/*
 *  call-seq:
 *     time.utc? => true or false
 *     time.gmt? => true or false
 *  
 *  Returns <code>true</code> if <i>time</i> represents a time in UTC
 *  (GMT).
 *     
 *     t = Time.now                        #=> Wed Apr 09 08:56:04 CDT 2003
 *     t.utc?                              #=> false
 *     t = Time.gm(2000,"jan",1,20,15,1)   #=> Sat Jan 01 20:15:01 UTC 2000
 *     t.utc?                              #=> true
 *
 *     t = Time.now                        #=> Wed Apr 09 08:56:03 CDT 2003
 *     t.gmt?                              #=> false
 *     t = Time.gm(2000,1,1,20,15,1)       #=> Sat Jan 01 20:15:01 UTC 2000
 *     t.gmt?                              #=> true
 */

static VALUE
time_utc_p(time)
    VALUE time;
{
    struct time_object *tobj;

    GetTimeval(time, tobj);
    if (tobj->gmt) return Qtrue;
    return Qfalse;
}

/*
 * call-seq:
 *   time.hash   => fixnum
 *
 * Return a hash code for this time object.
 */

static VALUE
time_hash(time)
    VALUE time;
{
    struct time_object *tobj;
    long hash;

    GetTimeval(time, tobj);
    hash = tobj->tv.tv_sec ^ tobj->tv.tv_usec;
    return LONG2FIX(hash);
}

/* :nodoc: */
static VALUE
time_init_copy(copy, time)
    VALUE copy, time;
{
    struct time_object *tobj, *tcopy;

    if (copy == time) return copy;
    time_modify(copy);
    if (TYPE(time) != T_DATA || RDATA(time)->dfree != time_free) {
        rb_raise(rb_eTypeError, "wrong argument type");
    }
    GetTimeval(time, tobj);
    GetTimeval(copy, tcopy);
    MEMCPY(tcopy, tobj, struct time_object, 1);

    return copy;
}

static VALUE
time_dup(time)
    VALUE time;
{
    VALUE dup = time_s_alloc(rb_cTime);
    time_init_copy(dup, time);
    return dup;
}

/*
 *  call-seq:
 *     time.localtime => time
 *  
 *  Converts <i>time</i> to local time (using the local time zone in
 *  effect for this process) modifying the receiver.
 *     
 *     t = Time.gm(2000, "jan", 1, 20, 15, 1)
 *     t.gmt?        #=> true
 *     t.localtime   #=> Sat Jan 01 14:15:01 CST 2000
 *     t.gmt?        #=> false
 */

static VALUE
time_localtime(time)
    VALUE time;
{
    struct time_object *tobj;
    struct tm *tm_tmp;
    time_t t;

    GetTimeval(time, tobj);
    if (!tobj->gmt) {
        if (tobj->tm_got)
            return time;
    }
    else {
        time_modify(time);
    }
    t = tobj->tv.tv_sec;
    tm_tmp = localtime(&t);
    if (!tm_tmp)
        rb_raise(rb_eArgError, "localtime error");
    tobj->tm = *tm_tmp;
    tobj->tm_got = 1;
    tobj->gmt = 0;
    return time;
}

/*
 *  call-seq:
 *     time.gmtime    => time
 *     time.utc       => time
 *  
 *  Converts <i>time</i> to UTC (GMT), modifying the receiver.
 *     
 *     t = Time.now   #=> Wed Apr 09 08:56:03 CDT 2003
 *     t.gmt?         #=> false
 *     t.gmtime       #=> Wed Apr 09 13:56:03 UTC 2003
 *     t.gmt?         #=> true
 *
 *     t = Time.now   #=> Wed Apr 09 08:56:04 CDT 2003
 *     t.utc?         #=> false
 *     t.utc          #=> Wed Apr 09 13:56:04 UTC 2003
 *     t.utc?         #=> true
 */

static VALUE
time_gmtime(time)
    VALUE time;
{
    struct time_object *tobj;
    struct tm *tm_tmp;
    time_t t;

    GetTimeval(time, tobj);
    if (tobj->gmt) {
        if (tobj->tm_got)
            return time;
    }
    else {
        time_modify(time);
    }
    t = tobj->tv.tv_sec;
    tm_tmp = gmtime(&t);
    if (!tm_tmp)
        rb_raise(rb_eArgError, "gmtime error");
    tobj->tm = *tm_tmp;
    tobj->tm_got = 1;
    tobj->gmt = 1;
    return time;
}

/*
 *  call-seq:
 *     time.getlocal => new_time
 *  
 *  Returns a new <code>new_time</code> object representing <i>time</i> in
 *  local time (using the local time zone in effect for this process).
 *     
 *     t = Time.gm(2000,1,1,20,15,1)   #=> Sat Jan 01 20:15:01 UTC 2000
 *     t.gmt?                          #=> true
 *     l = t.getlocal                  #=> Sat Jan 01 14:15:01 CST 2000
 *     l.gmt?                          #=> false
 *     t == l                          #=> true
 */

static VALUE
time_getlocaltime(time)
    VALUE time;
{
    return time_localtime(time_dup(time));
}

/*
 *  call-seq:
 *     time.getgm  => new_time
 *     time.getutc => new_time
 *  
 *  Returns a new <code>new_time</code> object representing <i>time</i> in
 *  UTC.
 *     
 *     t = Time.local(2000,1,1,20,15,1)   #=> Sat Jan 01 20:15:01 CST 2000
 *     t.gmt?                             #=> false
 *     y = t.getgm                        #=> Sun Jan 02 02:15:01 UTC 2000
 *     y.gmt?                             #=> true
 *     t == y                             #=> true
 */

static VALUE
time_getgmtime(time)
    VALUE time;
{
    return time_gmtime(time_dup(time));
}

static VALUE
time_get_tm(time, gmt)
    VALUE time;
    int gmt;
{
    if (gmt) return time_gmtime(time);
    return time_localtime(time);
}

/*
 *  call-seq:
 *     time.asctime => string
 *     time.ctime   => string
 *  
 *  Returns a canonical string representation of <i>time</i>.
 *     
 *     Time.now.asctime   #=> "Wed Apr  9 08:56:03 2003"
 */

static VALUE
time_asctime(time)
    VALUE time;
{
    struct time_object *tobj;
    char *s;

    GetTimeval(time, tobj);
    if (tobj->tm_got == 0) {
        time_get_tm(time, tobj->gmt);
    }
    s = asctime(&tobj->tm);
    if (s[24] == '\n') s[24] = '\0';

    return rb_str_new2(s);
}

/*
 *  call-seq:
 *     time.inspect => string
 *     time.to_s    => string
 *  
 *  Returns a string representing <i>time</i>. Equivalent to calling
 *  <code>Time#strftime</code> with a format string of ``<code>%a</code>
 *  <code>%b</code> <code>%d</code> <code>%H:%M:%S</code>
 *  <code>%Z</code> <code>%Y</code>''.
 *     
 *     Time.now.to_s   #=> "Wed Apr 09 08:56:04 CDT 2003"
 */

static VALUE
time_to_s(time)
    VALUE time;
{
    struct time_object *tobj;
    char buf[128];
    int len;

    GetTimeval(time, tobj);
    if (tobj->tm_got == 0) {
        time_get_tm(time, tobj->gmt);
    }
    if (tobj->gmt == 1) {
        len = strftime(buf, 128, "%a %b %d %H:%M:%S UTC %Y", &tobj->tm);
    }
    else {
        len = strftime(buf, 128, "%a %b %d %H:%M:%S %Z %Y", &tobj->tm);
    }
    return rb_str_new(buf, len);
}

#if SIZEOF_TIME_T == SIZEOF_LONG
typedef unsigned long unsigned_time_t;
#elif SIZEOF_TIME_T == SIZEOF_INT
typedef unsigned int unsigned_time_t;
#elif SIZEOF_TIME_T == SIZEOF_LONG_LONG
typedef unsigned LONG_LONG unsigned_time_t;
#else
# error cannot find integer type which size is same as time_t.
#endif

static VALUE
time_add(tobj, offset, sign)
    struct time_object *tobj;
    VALUE offset;
    int sign;
{
    double v = NUM2DBL(offset);
    double f, d;
    unsigned_time_t sec_off;
    time_t usec_off, sec, usec;
    VALUE result;

    if (v < 0) {
        v = -v;
        sign = -sign;
    }
    d = modf(v, &f);
    sec_off = (unsigned_time_t)f;
    if (f != (double)sec_off)
        rb_raise(rb_eRangeError, "time %s %f out of Time range",
            sign < 0 ? "-" : "+", v);
    usec_off = (time_t)(d*1e6);

    if (sign < 0) {
        sec = tobj->tv.tv_sec - sec_off;
        usec = tobj->tv.tv_usec - usec_off;
        if (sec > tobj->tv.tv_sec)
            rb_raise(rb_eRangeError, "time - %f out of Time range", v);
    }
    else {
        sec = tobj->tv.tv_sec + sec_off;
        usec = tobj->tv.tv_usec + usec_off;
        if (sec < tobj->tv.tv_sec)
            rb_raise(rb_eRangeError, "time + %f out of Time range", v);
    }
    result = rb_time_new(sec, usec);
    if (tobj->gmt) {
        GetTimeval(result, tobj);
        tobj->gmt = 1;
    }
    return result;
}

/*
 *  call-seq:
 *     time + numeric => time
 *  
 *  Addition---Adds some number of seconds (possibly fractional) to
 *  <i>time</i> and returns that value as a new time.
 *     
 *     t = Time.now         #=> Wed Apr 09 08:56:03 CDT 2003
 *     t + (60 * 60 * 24)   #=> Thu Apr 10 08:56:03 CDT 2003
 */

static VALUE
time_plus(time1, time2)
    VALUE time1, time2;
{
    struct time_object *tobj;
    GetTimeval(time1, tobj);

    if (TYPE(time2) == T_DATA && RDATA(time2)->dfree == time_free) {
        rb_raise(rb_eTypeError, "time + time?");
    }
    return time_add(tobj, time2, 1);
}

/*
 *  call-seq:
 *     time - other_time => float
 *     time - numeric    => time
 *  
 *  Difference---Returns a new time that represents the difference
 *  between two times, or subtracts the given number of seconds in
 *  <i>numeric</i> from <i>time</i>.
 *     
 *     t = Time.now       #=> Wed Apr 09 08:56:03 CDT 2003
 *     t2 = t + 2592000   #=> Fri May 09 08:56:03 CDT 2003
 *     t2 - t             #=> 2592000.0
 *     t2 - 2592000       #=> Wed Apr 09 08:56:03 CDT 2003
 */

static VALUE
time_minus(time1, time2)
    VALUE time1, time2;
{
    struct time_object *tobj;

    GetTimeval(time1, tobj);
    if (TYPE(time2) == T_DATA && RDATA(time2)->dfree == time_free) {
        struct time_object *tobj2;
        double f;

        GetTimeval(time2, tobj2);
        f = (double)tobj->tv.tv_sec - (double)tobj2->tv.tv_sec;
        f += ((double)tobj->tv.tv_usec - (double)tobj2->tv.tv_usec)*1e-6;
        /* XXX: should check float overflow on 64bit time_t platforms */

        return rb_float_new(f);
    }
    return time_add(tobj, time2, -1);
}

/*
 * call-seq:
 *   time.succ   => new_time
 *
 * Return a new time object, one second later than <code>time</code>.
 */

static VALUE
time_succ(time)
    VALUE time;
{
    struct time_object *tobj;

    GetTimeval(time, tobj);
    return rb_time_new(tobj->tv.tv_sec + 1, tobj->tv.tv_usec);
}

/*
 *  call-seq:
 *     time.sec => fixnum
 *  
 *  Returns the second of the minute (0..60)<em>[Yes, seconds really can
 *  range from zero to 60. This allows the system to inject leap seconds
 *  every now and then to correct for the fact that years are not really
 *  a convenient number of hours long.]</em> for <i>time</i>.
 *     
 *     t = Time.now   #=> Wed Apr 09 08:56:04 CDT 2003
 *     t.sec          #=> 4
 */

static VALUE
time_sec(time)
    VALUE time;
{
    struct time_object *tobj;

    GetTimeval(time, tobj);
    if (tobj->tm_got == 0) {
        time_get_tm(time, tobj->gmt);
    }
    return INT2FIX(tobj->tm.tm_sec);
}

/*
 *  call-seq:
 *     time.min => fixnum
 *  
 *  Returns the minute of the hour (0..59) for <i>time</i>.
 *     
 *     t = Time.now   #=> Wed Apr 09 08:56:03 CDT 2003
 *     t.min          #=> 56
 */

static VALUE
time_min(time)
    VALUE time;
{
    struct time_object *tobj;

    GetTimeval(time, tobj);
    if (tobj->tm_got == 0) {
        time_get_tm(time, tobj->gmt);
    }
    return INT2FIX(tobj->tm.tm_min);
}

/*
 *  call-seq:
 *     time.hour => fixnum
 *  
 *  Returns the hour of the day (0..23) for <i>time</i>.
 *     
 *     t = Time.now   #=> Wed Apr 09 08:56:03 CDT 2003
 *     t.hour         #=> 8
 */

static VALUE
time_hour(time)
    VALUE time;
{
    struct time_object *tobj;

    GetTimeval(time, tobj);
    if (tobj->tm_got == 0) {
        time_get_tm(time, tobj->gmt);
    }
    return INT2FIX(tobj->tm.tm_hour);
}

/*
 *  call-seq:
 *     time.day  => fixnum
 *     time.mday => fixnum
 *  
 *  Returns the day of the month (1..n) for <i>time</i>.
 *     
 *     t = Time.now   #=> Wed Apr 09 08:56:03 CDT 2003
 *     t.day          #=> 9
 *     t.mday         #=> 9
 */

static VALUE
time_mday(time)
    VALUE time;
{
    struct time_object *tobj;

    GetTimeval(time, tobj);
    if (tobj->tm_got == 0) {
        time_get_tm(time, tobj->gmt);
    }
    return INT2FIX(tobj->tm.tm_mday);
}

/*
 *  call-seq:
 *     time.mon   => fixnum
 *     time.month => fixnum
 *  
 *  Returns the month of the year (1..12) for <i>time</i>.
 *     
 *     t = Time.now   #=> Wed Apr 09 08:56:03 CDT 2003
 *     t.mon          #=> 4
 *     t.month        #=> 4
 */

static VALUE
time_mon(time)
    VALUE time;
{
    struct time_object *tobj;

    GetTimeval(time, tobj);
    if (tobj->tm_got == 0) {
        time_get_tm(time, tobj->gmt);
    }
    return INT2FIX(tobj->tm.tm_mon+1);
}

/*
 *  call-seq:
 *     time.year => fixnum
 *  
 *  Returns the year for <i>time</i> (including the century).
 *     
 *     t = Time.now   #=> Wed Apr 09 08:56:04 CDT 2003
 *     t.year         #=> 2003
 */

static VALUE
time_year(time)
    VALUE time;
{
    struct time_object *tobj;

    GetTimeval(time, tobj);
    if (tobj->tm_got == 0) {
        time_get_tm(time, tobj->gmt);
    }
    return LONG2NUM((long)tobj->tm.tm_year+1900);
}

/*
 *  call-seq:
 *     time.wday => fixnum
 *  
 *  Returns an integer representing the day of the week, 0..6, with
 *  Sunday == 0.
 *     
 *     t = Time.now   #=> Wed Apr 09 08:56:04 CDT 2003
 *     t.wday         #=> 3
 */

static VALUE
time_wday(time)
    VALUE time;
{
    struct time_object *tobj;

    GetTimeval(time, tobj);
    if (tobj->tm_got == 0) {
        time_get_tm(time, tobj->gmt);
    }
    return INT2FIX(tobj->tm.tm_wday);
}

/*
 *  call-seq:
 *     time.yday => fixnum
 *  
 *  Returns an integer representing the day of the year, 1..366.
 *     
 *     t = Time.now   #=> Wed Apr 09 08:56:04 CDT 2003
 *     t.yday         #=> 99
 */

static VALUE
time_yday(time)
    VALUE time;
{
    struct time_object *tobj;

    GetTimeval(time, tobj);
    if (tobj->tm_got == 0) {
        time_get_tm(time, tobj->gmt);
    }
    return INT2FIX(tobj->tm.tm_yday+1);
}

/*
 *  call-seq:
 *     time.isdst => true or false
 *     time.dst?  => true or false
 *  
 *  Returns <code>true</code> if <i>time</i> occurs during Daylight
 *  Saving Time in its time zone.
 *     
 *     Time.local(2000, 7, 1).isdst   #=> true
 *     Time.local(2000, 1, 1).isdst   #=> false
 *     Time.local(2000, 7, 1).dst?    #=> true
 *     Time.local(2000, 1, 1).dst?    #=> false
 */

static VALUE
time_isdst(time)
    VALUE time;
{
    struct time_object *tobj;

    GetTimeval(time, tobj);
    if (tobj->tm_got == 0) {
        time_get_tm(time, tobj->gmt);
    }
    return tobj->tm.tm_isdst?Qtrue:Qfalse;
}

/*
 *  call-seq:
 *     time.zone => string
 *  
 *  Returns the name of the time zone used for <i>time</i>. As of Ruby
 *  1.8, returns ``UTC'' rather than ``GMT'' for UTC times.
 *     
 *     t = Time.gm(2000, "jan", 1, 20, 15, 1)
 *     t.zone   #=> "UTC"
 *     t = Time.local(2000, "jan", 1, 20, 15, 1)
 *     t.zone   #=> "CST"
 */

static VALUE
time_zone(time)
    VALUE time;
{
    struct time_object *tobj;
#if !defined(HAVE_TM_ZONE) && (!defined(HAVE_TZNAME) || !defined(HAVE_DAYLIGHT))
    char buf[64];
    int len;
#endif
    
    GetTimeval(time, tobj);
    if (tobj->tm_got == 0) {
        time_get_tm(time, tobj->gmt);
    }

    if (tobj->gmt == 1) {
        return rb_str_new2("UTC");
    }
#if defined(HAVE_TM_ZONE)
    return rb_str_new2(tobj->tm.tm_zone);
#elif defined(HAVE_TZNAME) && defined(HAVE_DAYLIGHT)
    return rb_str_new2(tzname[daylight && tobj->tm.tm_isdst]);
#else
    len = strftime(buf, 64, "%Z", &tobj->tm);
    return rb_str_new(buf, len);
#endif
}

/*
 *  call-seq:
 *     time.gmt_offset => fixnum
 *     time.gmtoff     => fixnum
 *     time.utc_offset => fixnum
 *  
 *  Returns the offset in seconds between the timezone of <i>time</i>
 *  and UTC.
 *     
 *     t = Time.gm(2000,1,1,20,15,1)   #=> Sat Jan 01 20:15:01 UTC 2000
 *     t.gmt_offset                    #=> 0
 *     l = t.getlocal                  #=> Sat Jan 01 14:15:01 CST 2000
 *     l.gmt_offset                    #=> -21600
 */

static VALUE
time_utc_offset(time)
    VALUE time;
{
    struct time_object *tobj;

    GetTimeval(time, tobj);
    if (tobj->tm_got == 0) {
        time_get_tm(time, tobj->gmt);
    }

    if (tobj->gmt == 1) {
        return INT2FIX(0);
    }
    else {
#if defined(HAVE_STRUCT_TM_TM_GMTOFF)
        return INT2NUM(tobj->tm.tm_gmtoff);
#else
        struct tm *u, *l;
        time_t t;
        long off;
        l = &tobj->tm;
        t = tobj->tv.tv_sec;
        u = gmtime(&t);
        if (!u)
            rb_raise(rb_eArgError, "gmtime error");
        if (l->tm_year != u->tm_year)
            off = l->tm_year < u->tm_year ? -1 : 1;
        else if (l->tm_mon != u->tm_mon)
            off = l->tm_mon < u->tm_mon ? -1 : 1;
        else if (l->tm_mday != u->tm_mday)
            off = l->tm_mday < u->tm_mday ? -1 : 1;
        else
            off = 0;
        off = off * 24 + l->tm_hour - u->tm_hour;
        off = off * 60 + l->tm_min - u->tm_min;
        off = off * 60 + l->tm_sec - u->tm_sec;
        return LONG2FIX(off);
#endif
    }
}

/*
 *  call-seq:
 *     time.to_a => array
 *  
 *  Returns a ten-element <i>array</i> of values for <i>time</i>:
 *  {<code>[ sec, min, hour, day, month, year, wday, yday, isdst, zone
 *  ]</code>}. See the individual methods for an explanation of the
 *  valid ranges of each value. The ten elements can be passed directly
 *  to <code>Time::utc</code> or <code>Time::local</code> to create a
 *  new <code>Time</code>.
 *     
 *     now = Time.now   #=> Wed Apr 09 08:56:04 CDT 2003
 *     t = now.to_a     #=> [4, 56, 8, 9, 4, 2003, 3, 99, true, "CDT"]
 */

static VALUE
time_to_a(time)
    VALUE time;
{
    struct time_object *tobj;

    GetTimeval(time, tobj);
    if (tobj->tm_got == 0) {
        time_get_tm(time, tobj->gmt);
    }
    return rb_ary_new3(10,
                    INT2FIX(tobj->tm.tm_sec),
                    INT2FIX(tobj->tm.tm_min),
                    INT2FIX(tobj->tm.tm_hour),
                    INT2FIX(tobj->tm.tm_mday),
                    INT2FIX(tobj->tm.tm_mon+1),
                    LONG2NUM((long)tobj->tm.tm_year+1900),
                    INT2FIX(tobj->tm.tm_wday),
                    INT2FIX(tobj->tm.tm_yday+1),
                    tobj->tm.tm_isdst?Qtrue:Qfalse,
                    time_zone(time));
}

#define SMALLBUF 100
static int
rb_strftime(buf, format, time)
    char **buf;
    const char *format;
    struct tm *time;
{
    int size, len, flen;

    (*buf)[0] = '\0';
    flen = strlen(format);
    if (flen == 0) {
        return 0;
    }
    len = strftime(*buf, SMALLBUF, format, time);
    if (len != 0 || **buf == '\0') return len;
    for (size=1024; ; size*=2) {
        *buf = xmalloc(size);
        (*buf)[0] = '\0';
        len = strftime(*buf, size, format, time);
        /*
         * buflen can be zero EITHER because there's not enough
         * room in the string, or because the control command
         * goes to the empty string. Make a reasonable guess that
         * if the buffer is 1024 times bigger than the length of the
         * format string, it's not failing for lack of room.
         */
        if (len > 0 || size >= 1024 * flen) return len;
        free(*buf);
    }
    /* not reached */
}

/*
 *  call-seq:
 *     time.strftime( string ) => string
 *  
 *  Formats <i>time</i> according to the directives in the given format
 *  string. Any text not listed as a directive will be passed through
 *  to the output string.
 *
 *  Format meaning:
 *    %a - The abbreviated weekday name (``Sun'')
 *    %A - The  full  weekday  name (``Sunday'')
 *    %b - The abbreviated month name (``Jan'')
 *    %B - The  full  month  name (``January'')
 *    %c - The preferred local date and time representation
 *    %d - Day of the month (01..31)
 *    %H - Hour of the day, 24-hour clock (00..23)
 *    %I - Hour of the day, 12-hour clock (01..12)
 *    %j - Day of the year (001..366)
 *    %m - Month of the year (01..12)
 *    %M - Minute of the hour (00..59)
 *    %p - Meridian indicator (``AM''  or  ``PM'')
 *    %S - Second of the minute (00..60)
 *    %U - Week  number  of the current year,
 *            starting with the first Sunday as the first
 *            day of the first week (00..53)
 *    %W - Week  number  of the current year,
 *            starting with the first Monday as the first
 *            day of the first week (00..53)
 *    %w - Day of the week (Sunday is 0, 0..6)
 *    %x - Preferred representation for the date alone, no time
 *    %X - Preferred representation for the time alone, no date
 *    %y - Year without a century (00..99)
 *    %Y - Year with century
 *    %Z - Time zone name
 *    %% - Literal ``%'' character
 *     
 *     t = Time.now
 *     t.strftime("Printed on %m/%d/%Y")   #=> "Printed on 04/09/2003"
 *     t.strftime("at %I:%M%p")            #=> "at 08:56AM"
 */

static VALUE
time_strftime(time, format)
    VALUE time, format;
{
    struct time_object *tobj;
    char buffer[SMALLBUF], *buf = buffer;
    const char *fmt;
    long len;
    VALUE str;

    GetTimeval(time, tobj);
    if (tobj->tm_got == 0) {
        time_get_tm(time, tobj->gmt);
    }
    StringValue(format);
    format = rb_str_new4(format);
    fmt = RSTRING(format)->ptr;
    len = RSTRING(format)->len;
    if (len == 0) {
        rb_warning("strftime called with empty format string");
    }
    else if (strlen(fmt) < len) {
        /* Ruby string may contain \0's. */
        const char *p = fmt, *pe = fmt + len;

        str = rb_str_new(0, 0);
        while (p < pe) {
            len = rb_strftime(&buf, p, &tobj->tm);
            rb_str_cat(str, buf, len);
            p += strlen(p) + 1;
            if (buf != buffer) {
                free(buf);
                buf = buffer;
            }
            for (fmt = p; p < pe && !*p; ++p);
            if (p > fmt) rb_str_cat(str, fmt, p - fmt);
        }
        return str;
    }
    else {
        len = rb_strftime(&buf, RSTRING(format)->ptr, &tobj->tm);
    }
    str = rb_str_new(buf, len);
    if (buf != buffer) free(buf);
    return str;
}

/*
 *  call-seq:
 *     Time.times => struct_tms
 *  
 *  Deprecated in favor of <code>Process::times</code>
 */

static VALUE
time_s_times(obj)
    VALUE obj;
{
    rb_warn("obsolete method Time::times; use Process::times");
    return rb_proc_times(obj);
}

/*
 * undocumented
 */

static VALUE
time_mdump(time)
    VALUE time;
{
    struct time_object *tobj;
    struct tm *tm;
    unsigned long p, s;
    char buf[8];
    time_t t;
    int i;

    GetTimeval(time, tobj);

    t = tobj->tv.tv_sec;
    tm = gmtime(&t);

    if ((tm->tm_year & 0xffff) != tm->tm_year)
        rb_raise(rb_eArgError, "year too big to marshal");

    p = 0x1          << 31 | /*  1 */
        tm->tm_year  << 14 | /* 16 */
        tm->tm_mon   << 10 |