ruby/time.c

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

  time.c -

  $Author$
  $Date$
  created at: Tue Dec 28 14:31:59 JST 1993

  Copyright (C) 1993-2007 Yukihiro Matsumoto

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

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

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

#include <math.h>

VALUE rb_cTime;
static VALUE time_utc_offset _((VALUE));

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 *tobj)
{
    if (tobj) free(tobj);
}

static VALUE
time_s_alloc(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(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(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(time_t *secp, time_t *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(VALUE klass, time_t sec, time_t 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(time_t sec, time_t usec)
{
    return time_new_internal(rb_cTime, sec, usec);
}

static struct timeval
time_timeval(VALUE time, int interval)
{
    struct timeval t;
    const 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+0.5);
	}
	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(VALUE time)
{
    return time_timeval(time, Qtrue);
}

struct timeval
rb_time_timeval(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(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 const char *months[] = {
    "jan", "feb", "mar", "apr", "may", "jun",
    "jul", "aug", "sep", "oct", "nov", "dec",
};

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

    return NUM2LONG(obj);
}

static void
time_arg(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_LEN(s) == 3 &&
		    strcasecmp(months[i], RSTRING_PTR(v[1])) == 0) {
		    tm->tm_mon = i;
		    break;
		}
	    }
	    if (tm->tm_mon == -1) {
		char c = RSTRING_PTR(s)[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])) {
	/* when argc == 8, v[6] is timezone, but ignored */
	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 > 24
	|| (tm->tm_hour == 24 && (tm->tm_min > 0 || tm->tm_sec > 0))
	|| 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(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(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(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;
}

#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 time_t
search_time_t(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 = (time_t)~((unsigned_time_t)~(time_t)0 >> 1);
#else
    guess_lo = 0;
#endif
    guess_hi = ((time_t)-1) < ((time_t)0) ?
	       (time_t)((unsigned_time_t)~(time_t)0 >> 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(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(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(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(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(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(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(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(VALUE time1, VALUE 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(VALUE time1, VALUE 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(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(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(VALUE copy, VALUE 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(VALUE time)
{
    VALUE dup = time_s_alloc(CLASS_OF(time));
    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(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(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(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(VALUE time)
{
    return time_gmtime(time_dup(time));
}

static VALUE
time_get_tm(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(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(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, "%Y-%m-%d %H:%M:%S UTC", &tobj->tm);
    }
    else {
	time_t off;
	char buf2[32];
	char sign = '+';
#if defined(HAVE_STRUCT_TM_TM_GMTOFF)
	off = tobj->tm.tm_gmtoff;
#else
	VALUE tmp = time_utc_offset(time);
	off = NUM2INT(tmp);
#endif
	if (off < 0) {
	    sign = '-';
	    off = -off;
	}
	sprintf(buf2, "%%Y-%%m-%%d %%H:%%M:%%S %c%02d%02d",
		sign, (int)(off/3600), (int)(off%3600/60));
	len = strftime(buf, 128, buf2, &tobj->tm);
    }
    return rb_str_new(buf, len);
}

static VALUE
time_add(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+0.5);

    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(VALUE time1, VALUE 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(VALUE time1, VALUE 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(VALUE time)
{
    struct time_object *tobj;
    int gmt;

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

/*
 *  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(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);
}

VALUE
rb_time_succ(VALUE time)
{
  return time_succ(time);
}

/*
 *  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(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(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(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(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(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(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);
}

#define wday_p(n) {\
    struct time_object *tobj;\
    GetTimeval(time, tobj);\
    if (tobj->tm_got == 0) {\
	time_get_tm(time, tobj->gmt);\
    }\
    return (tobj->tm.tm_wday == (n)) ? Qtrue : Qfalse;\
}

/*
 *  call-seq:
 *     time.sunday? => true or false
 *  
 *  Returns <code>true</code> if <i>time</i> represents Sunday.
 *     
 *     t = Time.now   #=> Sun Oct 23 00:14:54 UTC 2005
 *     t.sunday?      #=> true
 */

static VALUE
time_sunday(VALUE time)
{
    wday_p(0);
}

/*
 *  call-seq:
 *     time.monday? => true or false
 *  
 *  Returns <code>true</code> if <i>time</i> represents Monday.
 */

static VALUE
time_monday(VALUE time)
{
    wday_p(1);
}

/*
 *  call-seq:
 *     time.tuesday? => true or false
 *  
 *  Returns <code>true</code> if <i>time</i> represents Tuesday.
 */

static VALUE
time_tuesday(VALUE time)
{
    wday_p(2);
}

/*
 *  call-seq:
 *     time.wednesday? => true or false
 *  
 *  Returns <code>true</code> if <i>time</i> represents Wednesday.
 */

static VALUE
time_wednesday(VALUE time)
{
    wday_p(3);
}

/*
 *  call-seq:
 *     time.thursday? => true or false
 *  
 *  Returns <code>true</code> if <i>time</i> represents Thursday.
 */

static VALUE
time_thursday(VALUE time)
{
    wday_p(4);
}

/*
 *  call-seq:
 *     time.friday? => true or false
 *  
 *  Returns <code>true</code> if <i>time</i> represents Friday.
 */

static VALUE
time_friday(VALUE time)
{
    wday_p(5);
}

/*
 *  call-seq:
 *     time.saturday? => true or false
 *  
 *  Returns <code>true</code> if <i>time</i> represents Saturday.
 */

static VALUE
time_saturday(VALUE time)
{
    wday_p(6);
}

/*
 *  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(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(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(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(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(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(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(VALUE time, VALUE 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_PTR(format);
    len = RSTRING_LEN(format);
    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);
	    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_PTR(format), &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(VALUE obj)
{
    rb_warn("obsolete method Time::times; use Process::times");
    return rb_proc_times(obj);
}

/*
 * undocumented
 */

static VALUE
time_mdump(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 = 0x1UL        << 31 | /*  1 */
	tobj->gmt    << 30 | /*  1 */
	tm->tm_year  << 14 | /* 16 */
	tm->tm_mon   << 10 | /*  4 */
	tm->tm_mday  <<  5 | /*  5 */
	tm->tm_hour;         /*  5 */
    s = tm->tm_min   << 26 | /*  6 */
	tm->tm_sec   << 20 | /*  6 */
	tobj->tv.tv_usec;    /* 20 */

    for (i=0; i<4; i++) {
	buf[i] = p & 0xff;
	p = RSHIFT(p, 8);
    }
    for (i=4; i<8; i++) {
	buf[i] = s & 0xff;
	s = RSHIFT(s, 8);
    }

    return rb_str_new(buf, 8);
}

/*
 * call-seq:
 *   time._dump   => string
 *
 * Dump _time_ for marshaling.
 */

static VALUE
time_dump(int argc, VALUE *argv, VALUE time)
{
    VALUE str;

    rb_scan_args(argc, argv, "01", 0);
    str = time_mdump(time); 
    rb_copy_generic_ivar(str, time);

    return str;
}

/*
 * undocumented
 */

static VALUE
time_mload(VALUE time, VALUE str)
{
    struct time_object *tobj;
    unsigned long p, s;
    time_t sec, usec;
    unsigned char *buf;
    struct tm tm;
    int i, gmt;

    time_modify(time);
    StringValue(str);
    buf = (unsigned char *)RSTRING_PTR(str);
    if (RSTRING_LEN(str) != 8) {
	rb_raise(rb_eTypeError, "marshaled time format differ");
    }

    p = s = 0;
    for (i=0; i<4; i++) {
	p |= buf[i]<<(8*i);
    }
    for (i=4; i<8; i++) {
	s |= buf[i]<<(8*(i-4));
    }

    if ((p & (1UL<<31)) == 0) {
        gmt = 0;
	sec = p;
	usec = s;
    }
    else {
	p &= ~(1UL<<31);
	gmt        = (p >> 30) & 0x1;
	tm.tm_year = (p >> 14) & 0xffff;
	tm.tm_mon  = (p >> 10) & 0xf;
	tm.tm_mday = (p >>  5) & 0x1f;
	tm.tm_hour =  p        & 0x1f;
	tm.tm_min  = (s >> 26) & 0x3f;
	tm.tm_sec  = (s >> 20) & 0x3f;
	tm.tm_isdst = 0;

	sec = make_time_t(&tm, Qtrue);
	usec = (time_t)(s & 0xfffff);
    }
    time_overflow_p(&sec, &usec);

    GetTimeval(time, tobj);
    tobj->tm_got = 0;
    tobj->gmt = gmt;
    tobj->tv.tv_sec = sec;
    tobj->tv.tv_usec = usec;
    return time;
}

/*
 * call-seq:
 *   Time._load(string)   => time
 *
 * Unmarshal a dumped +Time+ object.
 */

static VALUE
time_load(VALUE klass, VALUE str)
{
    VALUE time = time_s_alloc(klass);

    rb_copy_generic_ivar(time, str);
    time_mload(time, str);
    return time;
}

/*
 *  <code>Time</code> is an abstraction of dates and times. Time is
 *  stored internally as the number of seconds and microseconds since
 *  the <em>epoch</em>, January 1, 1970 00:00 UTC. On some operating
 *  systems, this offset is allowed to be negative. Also see the
 *  library modules <code>Date</code> and <code>ParseDate</code>. The
 *  <code>Time</code> class treats GMT (Greenwich Mean Time) and UTC
 *  (Coordinated Universal Time)<em>[Yes, UTC really does stand for
 *  Coordinated Universal Time. There was a committee involved.]</em>
 *  as equivalent.  GMT is the older way of referring to these
 *  baseline times but persists in the names of calls on Posix
 *  systems.
 *     
 *  All times are stored with some number of microseconds. Be aware of
 *  this fact when comparing times with each other---times that are
 *  apparently equal when displayed may be different when compared.
 */

void
Init_Time(void)
{
    rb_cTime = rb_define_class("Time", rb_cObject);
    rb_include_module(rb_cTime, rb_mComparable);

    rb_define_alloc_func(rb_cTime, time_s_alloc);
    rb_define_singleton_method(rb_cTime, "now", rb_class_new_instance, -1);
    rb_define_singleton_method(rb_cTime, "at", time_s_at, -1);
    rb_define_singleton_method(rb_cTime, "utc", time_s_mkutc, -1);
    rb_define_singleton_method(rb_cTime, "gm", time_s_mkutc, -1);
    rb_define_singleton_method(rb_cTime, "local", time_s_mktime, -1);
    rb_define_singleton_method(rb_cTime, "mktime", time_s_mktime, -1);

    rb_define_singleton_method(rb_cTime, "times", time_s_times, 0);

    rb_define_method(rb_cTime, "to_i", time_to_i, 0);
    rb_define_method(rb_cTime, "to_f", time_to_f, 0);
    rb_define_method(rb_cTime, "<=>", time_cmp, 1);
    rb_define_method(rb_cTime, "eql?", time_eql, 1);
    rb_define_method(rb_cTime, "hash", time_hash, 0);
    rb_define_method(rb_cTime, "initialize", time_init, 0);
    rb_define_method(rb_cTime, "initialize_copy", time_init_copy, 1);

    rb_define_method(rb_cTime, "localtime", time_localtime, 0);
    rb_define_method(rb_cTime, "gmtime", time_gmtime, 0);
    rb_define_method(rb_cTime, "utc", time_gmtime, 0);
    rb_define_method(rb_cTime, "getlocal", time_getlocaltime, 0);
    rb_define_method(rb_cTime, "getgm", time_getgmtime, 0);
    rb_define_method(rb_cTime, "getutc", time_getgmtime, 0);

    rb_define_method(rb_cTime, "ctime", time_asctime, 0);
    rb_define_method(rb_cTime, "asctime", time_asctime, 0);
    rb_define_method(rb_cTime, "to_s", time_to_s, 0);
    rb_define_method(rb_cTime, "inspect", time_to_s, 0);
    rb_define_method(rb_cTime, "to_a", time_to_a, 0);

    rb_define_method(rb_cTime, "+", time_plus, 1);
    rb_define_method(rb_cTime, "-", time_minus, 1);

    rb_define_method(rb_cTime, "succ", time_succ, 0);
    rb_define_method(rb_cTime, "sec", time_sec, 0);
    rb_define_method(rb_cTime, "min", time_min, 0);
    rb_define_method(rb_cTime, "hour", time_hour, 0);
    rb_define_method(rb_cTime, "mday", time_mday, 0);
    rb_define_method(rb_cTime, "day", time_mday, 0);
    rb_define_method(rb_cTime, "mon", time_mon, 0);
    rb_define_method(rb_cTime, "month", time_mon, 0);
    rb_define_method(rb_cTime, "year", time_year, 0);
    rb_define_method(rb_cTime, "wday", time_wday, 0);
    rb_define_method(rb_cTime, "yday", time_yday, 0);
    rb_define_method(rb_cTime, "isdst", time_isdst, 0);
    rb_define_method(rb_cTime, "dst?", time_isdst, 0);
    rb_define_method(rb_cTime, "zone", time_zone, 0);
    rb_define_method(rb_cTime, "gmtoff", time_utc_offset, 0);
    rb_define_method(rb_cTime, "gmt_offset", time_utc_offset, 0);
    rb_define_method(rb_cTime, "utc_offset", time_utc_offset, 0);

    rb_define_method(rb_cTime, "utc?", time_utc_p, 0);
    rb_define_method(rb_cTime, "gmt?", time_utc_p, 0);

    rb_define_method(rb_cTime, "sunday?", time_sunday, 0);
    rb_define_method(rb_cTime, "monday?", time_monday, 0);
    rb_define_method(rb_cTime, "tuesday?", time_tuesday, 0);
    rb_define_method(rb_cTime, "wednesday?", time_wednesday, 0);
    rb_define_method(rb_cTime, "thursday?", time_thursday, 0);
    rb_define_method(rb_cTime, "friday?", time_friday, 0);
    rb_define_method(rb_cTime, "saturday?", time_saturday, 0);

    rb_define_method(rb_cTime, "tv_sec", time_to_i, 0);
    rb_define_method(rb_cTime, "tv_usec", time_usec, 0);
    rb_define_method(rb_cTime, "usec", time_usec, 0);

    rb_define_method(rb_cTime, "strftime", time_strftime, 1);

    /* methods for marshaling */
    rb_define_method(rb_cTime, "_dump", time_dump, -1);
    rb_define_singleton_method(rb_cTime, "_load", time_load, 1);
#if 0
    /* Time will support marshal_dump and marshal_load in the future (1.9 maybe) */
    rb_define_method(rb_cTime, "marshal_dump", time_mdump, 0);
    rb_define_method(rb_cTime, "marshal_load", time_mload, 1);
#endif
}