decode_year(VALUE y, double style,
	    VALUE *nth, int *ry)
{
    int period;
    VALUE t;

    period = (style < 0) ?
	CM_PERIOD_GCY :
	CM_PERIOD_JCY;
    if (FIXNUM_P(y)) {
	long iy, it, inth;

	iy = FIX2LONG(y);
	if (iy >= (FIXNUM_MAX - 4712))
	    goto big;
	it = iy + 4712; /* shift */
	inth = DIV(it, ((long)period));
	*nth = LONG2FIX(inth);
	if (inth)
	    it = MOD(it, ((long)period));
	*ry = (int)it - 4712; /* unshift */
	return;
    }
  big:
    t = f_add(y, INT2FIX(4712)); /* shift */
    *nth = f_idiv(t, INT2FIX(period));
    if (f_nonzero_p(*nth))
	t = f_mod(t, INT2FIX(period));
    *ry = FIX2INT(t) - 4712; /* unshift */
}


get_s_jd(union DateData *x)
{
    assert(simple_dat_p(x));
    if (!have_jd_p(x)) {
	int jd, ns;

	assert(have_civil_p(x));
#ifndef USE_PACK
	c_civil_to_jd(x->s.year, x->s.mon, x->s.mday,
		      s_virtual_sg(x), &jd, &ns);
#else
	c_civil_to_jd(x->s.year, EX_MON(x->s.pc), EX_MDAY(x->s.pc),
		      s_virtual_sg(x), &jd, &ns);
#endif
	x->s.jd = jd;
	x->s.flags |= HAVE_JD;
    }
}

`Date._<format>(nil)` should return an empty Hash

Fix: https://github.com/ruby/date/issues/39

This is how versions previous to 3.2.1 behaved and Active Support
currently rely on this behavior.

https://github.com/rails/rails/blob/90357af08048ef5076730505f6e7b14a81f33d0c/activesupport/lib/active_support/values/time_zone.rb#L383-L384

Any Rails application upgrading to date `3.2.1` might run into unexpected errors.


date_s_parse(int argc, VALUE *argv, VALUE klass)
{
    VALUE str, comp, sg, opt;

    rb_scan_args(argc, argv, "03:", &str, &comp, &sg, &opt);
    if (!NIL_P(opt)) argc--;

    switch (argc) {
      case 0:
	str = rb_str_new2("-4712-01-01");
      case 1:
	comp = Qtrue;
      case 2:
	sg = INT2FIX(DEFAULT_SG);
    }

    {
        int argc2 = 2;
	VALUE argv2[3];
        argv2[0] = str;
        argv2[1] = comp;
        if (!NIL_P(opt)) argv2[argc2++] = opt;
	VALUE hash = date_s__parse(argc2, argv2, klass);
	return d_new_by_frags(klass, hash, sg);
    }
}


m_amjd(union DateData *x)
{
    VALUE r, sf;
    int df;

    r = m_real_jd(x);
    if (FIXNUM_P(r) && FIX2LONG(r) >= (FIXNUM_MIN + 2400001)) {
	long ir = FIX2LONG(r);
	ir -= 2400001;
	r = rb_rational_new1(LONG2FIX(ir));
    }
    else
	r = rb_rational_new1(f_sub(m_real_jd(x),
				   INT2FIX(2400001)));

    if (simple_dat_p(x))
	return r;

    df = m_df(x);
    if (df)
	r = f_add(r, isec_to_day(df));
    sf = m_sf(x);
    if (f_nonzero_p(sf))
	r = f_add(r, ns_to_day(sf));

    return r;
}


date_s_test_nth_kday(VALUE klass)
{
    if (!test_nth_kday(MIN_JD, MIN_JD + 366, GREGORIAN))
	return Qfalse;
    if (!test_nth_kday(2305814, 2598007, GREGORIAN))
	return Qfalse;
    if (!test_nth_kday(MAX_JD - 366, MAX_JD, GREGORIAN))
	return Qfalse;

    if (!test_nth_kday(MIN_JD, MIN_JD + 366, ITALY))
	return Qfalse;
    if (!test_nth_kday(2305814, 2598007, ITALY))
	return Qfalse;
    if (!test_nth_kday(MAX_JD - 366, MAX_JD, ITALY))
	return Qfalse;

    return Qtrue;
}


c_valid_commercial_p(int y, int w, int d, double sg,
		     int *rw, int *rd, int *rjd, int *ns)
{
    int ns2, ry2, rw2, rd2;

    if (d < 0)
	d += 8;
    if (w < 0) {
	int rjd2;

	c_commercial_to_jd(y + 1, 1, 1, sg, &rjd2, &ns2);
	c_jd_to_commercial(rjd2 + w * 7, sg, &ry2, &rw2, &rd2);
	if (ry2 != y)
	    return 0;
	w = rw2;
    }
    c_commercial_to_jd(y, w, d, sg, rjd, ns);
    c_jd_to_commercial(*rjd, sg, &ry2, rw, rd);
    if (y != ry2 || w != *rw || d != *rd)
	return 0;
    return 1;
}


c_julian_last_day_of_month(int y, int m)
{
    assert(m >= 1 && m <= 12);
    return monthtab[c_julian_leap_p(y) ? 1 : 0][m];
}


date_s__strptime_internal(int argc, VALUE *argv, VALUE klass,
			  const char *default_fmt)
{
    VALUE vstr, vfmt, hash;
    const char *str, *fmt;
    size_t slen, flen;

    rb_scan_args(argc, argv, "11", &vstr, &vfmt);

    StringValue(vstr);
    if (!rb_enc_str_asciicompat_p(vstr))
	rb_raise(rb_eArgError,
		 "string should have ASCII compatible encoding");
    str = RSTRING_PTR(vstr);
    slen = RSTRING_LEN(vstr);
    if (argc < 2) {
	fmt = default_fmt;
	flen = strlen(default_fmt);
    }
    else {
	StringValue(vfmt);
	if (!rb_enc_str_asciicompat_p(vfmt))
	    rb_raise(rb_eArgError,
		     "format should have ASCII compatible encoding");
	fmt = RSTRING_PTR(vfmt);
	flen = RSTRING_LEN(vfmt);
    }
    hash = rb_hash_new();
    if (NIL_P(date__strptime(str, slen, fmt, flen, hash)))
	return Qnil;

    {
	VALUE zone = ref_hash("zone");
	VALUE left = ref_hash("leftover");

	if (!NIL_P(zone)) {
	    rb_enc_copy(zone, vstr);
	    set_hash("zone", zone);
	}
	if (!NIL_P(left)) {
	    rb_enc_copy(left, vstr);
	    set_hash("leftover", left);
	}
    }

    return hash;
}


date_s_weeknum(int argc, VALUE *argv, VALUE klass)
{
    VALUE vy, vw, vd, vf, vsg, y, fr, fr2, ret;
    int w, d, f;
    double sg;

    rb_scan_args(argc, argv, "05", &vy, &vw, &vd, &vf, &vsg);

    y = INT2FIX(-4712);
    w = 0;
    d = 1;
    f = 0;
    fr2 = INT2FIX(0);
    sg = DEFAULT_SG;

    switch (argc) {
      case 5:
	val2sg(vsg, sg);
      case 4:
	f = NUM2INT(vf);
      case 3:
	num2int_with_frac(d, positive_inf);
      case 2:
	w = NUM2INT(vw);
      case 1:
	y = vy;
    }

    {
	VALUE nth;
	int ry, rw, rd, rjd, ns;

	if (!valid_weeknum_p(y, w, d, f, sg,
			     &nth, &ry,
			     &rw, &rd, &rjd,
			     &ns))
	    rb_raise(eDateError, "invalid date");

	ret = d_simple_new_internal(klass,
				    nth, rjd,
				    sg,
				    0, 0, 0,
				    HAVE_JD);
    }
    add_frac();
    return ret;
}


c_find_fdoy(int y, double sg, int *rjd, int *ns)
{
    int d, rm, rd;

    for (d = 1; d < 31; d++)
	if (c_valid_civil_p(y, 1, d, sg, &rm, &rd, rjd, ns))
	    return 1;
    return 0;
}


test_unit_v2v_iter2(VALUE (* conv1)(VALUE),
		    VALUE (* conv2)(VALUE))
{
    if (!test_unit_v2v(INT2FIX(0), conv1, conv2))
	return 0;
    if (!test_unit_v2v(INT2FIX(1), conv1, conv2))
	return 0;
    if (!test_unit_v2v(INT2FIX(2), conv1, conv2))
	return 0;
    if (!test_unit_v2v(INT2FIX(3), conv1, conv2))
	return 0;
    if (!test_unit_v2v(INT2FIX(11), conv1, conv2))
	return 0;
    if (!test_unit_v2v(INT2FIX(65535), conv1, conv2))
	return 0;
    if (!test_unit_v2v(INT2FIX(1073741823), conv1, conv2))
	return 0;
    if (!test_unit_v2v(INT2NUM(1073741824), conv1, conv2))
	return 0;
    if (!test_unit_v2v(rb_rational_new2(INT2FIX(0), INT2FIX(1)), conv1, conv2))
	return 0;
    if (!test_unit_v2v(rb_rational_new2(INT2FIX(1), INT2FIX(1)), conv1, conv2))
	return 0;
    if (!test_unit_v2v(rb_rational_new2(INT2FIX(1), INT2FIX(2)), conv1, conv2))
	return 0;
    if (!test_unit_v2v(rb_rational_new2(INT2FIX(2), INT2FIX(3)), conv1, conv2))
	return 0;
    return 1;
}


c_jd_to_ordinal(int jd, double sg, int *ry, int *rd)
{
    int rm2, rd2, rjd, ns;

    c_jd_to_civil(jd, sg, ry, &rm2, &rd2);
    c_find_fdoy(*ry, sg, &rjd, &ns);
    *rd = (jd - rjd) + 1;
}


date_s_valid_weeknum_p(int argc, VALUE *argv, VALUE klass)
{
    VALUE vy, vw, vd, vf, vsg;
    VALUE argv2[5];

    rb_scan_args(argc, argv, "41", &vy, &vw, &vd, &vf, &vsg);

    argv2[0] = vy;
    argv2[1] = vw;
    argv2[2] = vd;
    argv2[3] = vf;
    if (argc < 5)
	argv2[4] = INT2FIX(DEFAULT_SG);
    else
	argv2[4] = vsg;

    if (NIL_P(valid_weeknum_sub(5, argv2, klass, 0)))
	return Qfalse;
    return Qtrue;
}


d_lite_hour(VALUE self)
{
    get_d1(self);
    return INT2FIX(m_hour(dat));
}


datetime_s_jisx0301(int argc, VALUE *argv, VALUE klass)
{
    VALUE str, sg, opt;

    rb_scan_args(argc, argv, "02:", &str, &sg, &opt);
    if (!NIL_P(opt)) argc--;

    switch (argc) {
      case 0:
	str = rb_str_new2("-4712-01-01T00:00:00+00:00");
      case 1:
	sg = INT2FIX(DEFAULT_SG);
    }

    {
        int argc2 = 1;
        VALUE argv2[2];
        argv2[0] = str;
        argv2[1] = opt;
        if (!NIL_P(opt)) argc2++;
	VALUE hash = date_s__jisx0301(argc2, argv2, klass);
	return dt_new_by_frags(klass, hash, sg);
    }
}


m_local_df(union DateData *x)
{
    if (simple_dat_p(x))
	return 0;
    else {
	get_c_df(x);
	return local_df(x);
    }
}


civil_to_jd(VALUE y, int m, int d, double sg,
	    VALUE *nth, int *ry,
	    int *rjd,
	    int *ns)
{
    double style = guess_style(y, sg);

    if (style == 0) {
	int jd;

	c_civil_to_jd(FIX2INT(y), m, d, sg, &jd, ns);
	decode_jd(INT2FIX(jd), nth, rjd);
	if (f_zero_p(*nth))
	    *ry = FIX2INT(y);
	else {
	    VALUE nth2;
	    decode_year(y, *ns ? -1 : +1, &nth2, ry);
	}
    }
    else {
	decode_year(y, style, nth, ry);
	c_civil_to_jd(*ry, m, d, style, rjd, ns);
    }
}


date_s__xmlschema(int argc, VALUE *argv, VALUE klass)
{
    VALUE str, opt;

    rb_scan_args(argc, argv, "1:", &str, &opt);
    check_limit(str, opt);

    return date__xmlschema(str);
}


m_jd(union DateData *x)
{
    if (simple_dat_p(x)) {
	get_s_jd(x);
	return x->s.jd;
    }
    else {
	get_c_jd(x);
	return x->c.jd;
    }
}


d_trunc(VALUE d, VALUE *fr)
{
    VALUE rd;

    if (wholenum_p(d)) {
	rd = to_integer(d);
	*fr = INT2FIX(0);
    }
    else {
	rd = f_idiv(d, INT2FIX(1));
	*fr = f_mod(d, INT2FIX(1));
    }
    return rd;
}


m_real_cwyear(union DateData *x)
{
    VALUE nth, ry;
    int year;

    nth = m_nth(x);
    year = m_cwyear(x);

    if (f_zero_p(nth))
	return INT2FIX(year);

    encode_year(nth, year,
		m_gregorian_p(x) ? -1 : +1,
		&ry);
    return ry;
}


d_lite_rfc2822(VALUE self)
{
    return strftimev("%a, %-d %b %Y %T %z", self, set_tmx);
}


m_year(union DateData *x)
{
    if (simple_dat_p(x)) {
	get_s_civil(x);
	return x->s.year;
    }
    else {
	get_c_civil(x);
	return x->c.year;
    }
}


c_valid_ordinal_p(int y, int d, double sg,
		  int *rd, int *rjd, int *ns)
{
    int ry2, rd2;

    if (d < 0) {
	int rjd2, ns2;

	if (!c_find_ldoy(y, sg, &rjd2, &ns2))
	    return 0;
	c_jd_to_ordinal(rjd2 + d + 1, sg, &ry2, &rd2);
	if (ry2 != y)
	    return 0;
	d = rd2;
    }
    c_ordinal_to_jd(y, d, sg, rjd, ns);
    c_jd_to_ordinal(*rjd, sg, &ry2, &rd2);
    if (ry2 != y || rd2 != d)
	return 0;
    return 1;
}


d_lite_leap_p(VALUE self)
{
    int rjd, ns, ry, rm, rd;

    get_d1(self);
    if (m_gregorian_p(dat))
	return f_boolcast(c_gregorian_leap_p(m_year(dat)));

    c_civil_to_jd(m_year(dat), 3, 1, m_virtual_sg(dat),
		  &rjd, &ns);
    c_jd_to_civil(rjd - 1, m_virtual_sg(dat), &ry, &rm, &rd);
    return f_boolcast(rd == 29);
}


datetime_s_iso8601(int argc, VALUE *argv, VALUE klass)
{
    VALUE str, sg, opt;

    rb_scan_args(argc, argv, "02:", &str, &sg, &opt);
    if (!NIL_P(opt)) argc--;

    switch (argc) {
      case 0:
	str = rb_str_new2("-4712-01-01T00:00:00+00:00");
      case 1:
	sg = INT2FIX(DEFAULT_SG);
    }

    {
        int argc2 = 1;
        VALUE argv2[2];
        argv2[0] = str;
        argv2[1] = opt;
        if (!NIL_P(opt)) argc2--;
	VALUE hash = date_s__iso8601(argc2, argv2, klass);
	return dt_new_by_frags(klass, hash, sg);
    }
}


c_ordinal_to_jd(int y, int d, double sg, int *rjd, int *ns)
{
    int ns2;

    c_find_fdoy(y, sg, rjd, &ns2);
    *rjd += d - 1;
    *ns = (*rjd < sg) ? 0 : 1;
}


d_lite_day_fraction(VALUE self)
{
    get_d1(self);
    if (simple_dat_p(dat))
	return INT2FIX(0);
    return m_fr(dat);
}


date_s_rfc3339(int argc, VALUE *argv, VALUE klass)
{
    VALUE str, sg, opt;

    rb_scan_args(argc, argv, "02:", &str, &sg, &opt);
    if (!NIL_P(opt)) argc--;

    switch (argc) {
      case 0:
	str = rb_str_new2("-4712-01-01T00:00:00+00:00");
      case 1:
	sg = INT2FIX(DEFAULT_SG);
    }

    {
        int argc2 = 1;
        VALUE argv2[2];
        argv2[0] = str;
        if (!NIL_P(opt)) argv2[argc2++] = opt;
	VALUE hash = date_s__rfc3339(argc2, argv2, klass);
	return d_new_by_frags(klass, hash, sg);
    }
}


date_s_valid_nth_kday_p(int argc, VALUE *argv, VALUE klass)
{
    VALUE vy, vm, vn, vk, vsg;
    VALUE argv2[5];

    rb_scan_args(argc, argv, "41", &vy, &vm, &vn, &vk, &vsg);

    argv2[0] = vy;
    argv2[1] = vm;
    argv2[2] = vn;
    argv2[3] = vk;
    if (argc < 5)
	argv2[4] = INT2FIX(DEFAULT_SG);
    else
	argv2[4] = vsg;

    if (NIL_P(valid_nth_kday_sub(5, argv2, klass, 0)))
	return Qfalse;
    return Qtrue;
}


m_canonicalize_jd(VALUE obj, union DateData *x)
{
    if (simple_dat_p(x)) {
	get_s_jd(x);
	canonicalize_s_jd(obj, x);
    }
    else {
	get_c_jd(x);
	canonicalize_c_jd(obj, x);
    }
}


c_jd_to_nth_kday(int jd, double sg, int *ry, int *rm, int *rn, int *rk)
{
    int rd, rjd, ns2;

    c_jd_to_civil(jd, sg, ry, rm, &rd);
    c_find_fdom(*ry, *rm, sg, &rjd, &ns2);
    *rn = DIV(jd - rjd, 7) + 1;
    *rk = c_jd_to_wday(jd);
}


set_of(union DateData *x, int of)
{
    assert(complex_dat_p(x));
    get_c_jd(x);
    get_c_df(x);
    clear_civil(x);
    x->c.of = of;
}


clear_civil(union DateData *x)
{
    if (simple_dat_p(x)) {
	x->s.year = 0;
#ifndef USE_PACK
	x->s.mon = 0;
	x->s.mday = 0;
#else
	x->s.pc = 0;
#endif
	x->s.flags &= ~HAVE_CIVIL;
    }
    else {
	x->c.year = 0;
#ifndef USE_PACK
	x->c.mon = 0;
	x->c.mday = 0;
	x->c.hour = 0;
	x->c.min = 0;
	x->c.sec = 0;
#else
	x->c.pc = 0;
#endif
	x->c.flags &= ~(HAVE_CIVIL | HAVE_TIME);
    }
}


m_df(union DateData *x)
{
    if (simple_dat_p(x))
	return 0;
    else {
	get_c_df(x);
	return x->c.df;
    }
}


dt_new_by_frags(VALUE klass, VALUE hash, VALUE sg)
{
    VALUE jd, sf, t;
    int df, of;

    if (!c_valid_start_p(NUM2DBL(sg))) {
	sg = INT2FIX(DEFAULT_SG);
	rb_warning("invalid start is ignored");
    }

    if (NIL_P(hash))
	rb_raise(eDateError, "invalid date");

    if (NIL_P(ref_hash("jd")) &&
	NIL_P(ref_hash("yday")) &&
	!NIL_P(ref_hash("year")) &&
	!NIL_P(ref_hash("mon")) &&
	!NIL_P(ref_hash("mday"))) {
	jd = rt__valid_civil_p(ref_hash("year"),
			       ref_hash("mon"),
			       ref_hash("mday"), sg);

	if (NIL_P(ref_hash("hour")))
	    set_hash("hour", INT2FIX(0));
	if (NIL_P(ref_hash("min")))
	    set_hash("min", INT2FIX(0));
	if (NIL_P(ref_hash("sec")))
	    set_hash("sec", INT2FIX(0));
	else if (f_eqeq_p(ref_hash("sec"), INT2FIX(60)))
	    set_hash("sec", INT2FIX(59));
    }
    else {
	hash = rt_rewrite_frags(hash);
	hash = rt_complete_frags(klass, hash);
	jd = rt__valid_date_frags_p(hash, sg);
    }

    if (NIL_P(jd))
	rb_raise(eDateError, "invalid date");

    {
	int rh, rmin, rs;

	if (!c_valid_time_p(NUM2INT(ref_hash("hour")),
			    NUM2INT(ref_hash("min")),
			    NUM2INT(ref_hash("sec")),
			    &rh, &rmin, &rs))
	    rb_raise(eDateError, "invalid date");

	df = time_to_df(rh, rmin, rs);
    }

    t = ref_hash("sec_fraction");
    if (NIL_P(t))
	sf = INT2FIX(0);
    else
	sf = sec_to_ns(t);

    t = ref_hash("offset");
    if (NIL_P(t))
	of = 0;
    else {
	of = NUM2INT(t);
	if (of < -DAY_IN_SECONDS || of > DAY_IN_SECONDS) {
	    of = 0;
	    rb_warning("invalid offset is ignored");
	}
    }
    {
	VALUE nth;
	int rjd, rjd2;

	decode_jd(jd, &nth, &rjd);
	rjd2 = jd_local_to_utc(rjd, df, of);
	df = df_local_to_utc(df, of);

	return d_complex_new_internal(klass,
				      nth, rjd2,
				      df, sf,
				      of, NUM2DBL(sg),
				      0, 0, 0,
				      0, 0, 0,
				      HAVE_JD | HAVE_DF);
    }
}


time_to_time(VALUE self)
{
    return self;
}


d_lite_sunday_p(VALUE self)
{
    get_d1(self);
    return f_boolcast(m_wday(dat) == 0);
}


test_weeknum(int from, int to, int f, double sg)
{
    int j;

    fprintf(stderr, "test_weeknum: %d...%d (%d) - %.0f\n",
	    from, to, to - from, sg);
    for (j = from; j <= to; j++) {
	int y, w, d, rj, ns;

	c_jd_to_weeknum(j, f, sg, &y, &w, &d);
	c_weeknum_to_jd(y, w, d, f, sg, &rj, &ns);
	if (j != rj) {
	    fprintf(stderr, "%d != %d\n", j, rj);
	    return 0;
	}
    }
    return 1;
}


time_to_date(VALUE self)
{
    VALUE y, nth, ret;
    int ry, m, d;

    y = f_year(self);
    m = FIX2INT(f_mon(self));
    d = FIX2INT(f_mday(self));

    decode_year(y, -1, &nth, &ry);

    ret = d_simple_new_internal(cDate,
				nth, 0,
				GREGORIAN,
				ry, m, d,
				HAVE_CIVIL);
    {
	get_d1(ret);
	set_sg(dat, DEFAULT_SG);
    }
    return ret;
}


dup_obj(VALUE self)
{
    get_d1a(self);

    if (simple_dat_p(adat)) {
	VALUE new = d_lite_s_alloc_simple(rb_obj_class(self));
	{
	    get_d1b(new);
	    bdat->s = adat->s;
	    RB_OBJ_WRITTEN(new, Qundef, bdat->s.nth);
	    return new;
	}
    }
    else {
	VALUE new = d_lite_s_alloc_complex(rb_obj_class(self));
	{
	    get_d1b(new);
	    bdat->c = adat->c;
	    RB_OBJ_WRITTEN(new, Qundef, bdat->c.nth);
	    RB_OBJ_WRITTEN(new, Qundef, bdat->c.sf);
	    return new;
	}
    }
}


d_lite_minus(VALUE self, VALUE other)
{
    if (k_date_p(other))
	return minus_dd(self, other);

    switch (TYPE(other)) {
      case T_FIXNUM:
	return d_lite_plus(self, LONG2NUM(-FIX2LONG(other)));
      case T_FLOAT:
	return d_lite_plus(self, DBL2NUM(-RFLOAT_VALUE(other)));
      default:
	expect_numeric(other);
	/* fall through */
      case T_BIGNUM:
      case T_RATIONAL:
	return d_lite_plus(self, f_negate(other));
    }
}


d_lite_prev_day(int argc, VALUE *argv, VALUE self)
{
    VALUE n;

    rb_scan_args(argc, argv, "01", &n);
    if (argc < 1)
	n = INT2FIX(1);
    return d_lite_minus(self, n);
}


datetime_s_httpdate(int argc, VALUE *argv, VALUE klass)
{
    VALUE str, sg, opt;

    rb_scan_args(argc, argv, "02:", &str, &sg, &opt);
    if (!NIL_P(opt)) argc--;

    switch (argc) {
      case 0:
	str = rb_str_new2("Mon, 01 Jan -4712 00:00:00 GMT");
      case 1:
	sg = INT2FIX(DEFAULT_SG);
    }

    {
        int argc2 = 1;
        VALUE argv2[2];
        argv2[0] = str;
        argv2[1] = opt;
        if (!NIL_P(opt)) argc2++;
	VALUE hash = date_s__httpdate(argc2, argv2, klass);
	return dt_new_by_frags(klass, hash, sg);
    }
}


date_s__httpdate(int argc, VALUE *argv, VALUE klass)
{
    VALUE str, opt;

    rb_scan_args(argc, argv, "1:", &str, &opt);
    check_limit(str, opt);

    return date__httpdate(str);
}


d_lite_downto(VALUE self, VALUE min)
{
    VALUE date;

    RETURN_ENUMERATOR(self, 1, &min);

    date = self;
    while (FIX2INT(d_lite_cmp(date, min)) >= 0) {
	rb_yield(date);
	date = d_lite_plus(date, INT2FIX(-1));
    }
    return self;
}


d_lite_s_alloc(VALUE klass)
{
    return d_lite_s_alloc_complex(klass);
}


d_lite_min(VALUE self)
{
    get_d1(self);
    return INT2FIX(m_min(dat));
}


date_s_valid_ordinal_p(int argc, VALUE *argv, VALUE klass)
{
    VALUE vy, vd, vsg;
    VALUE argv2[3];

    rb_scan_args(argc, argv, "21", &vy, &vd, &vsg);

    RETURN_FALSE_UNLESS_NUMERIC(vy);
    RETURN_FALSE_UNLESS_NUMERIC(vd);
    argv2[0] = vy;
    argv2[1] = vd;
    if (argc < 3)
	argv2[2] = INT2FIX(DEFAULT_SG);
    else
	argv2[2] = vsg;

    if (NIL_P(valid_ordinal_sub(3, argv2, klass, 0)))
	return Qfalse;
    return Qtrue;
}


datetime_to_time(VALUE self)
{
    volatile VALUE dup = dup_obj(self);
    {
	VALUE t;

	get_d1(dup);

	t = rb_funcall(rb_cTime,
		   rb_intern("new"),
                   7,
		   m_real_year(dat),
		   INT2FIX(m_mon(dat)),
		   INT2FIX(m_mday(dat)),
		   INT2FIX(m_hour(dat)),
		   INT2FIX(m_min(dat)),
		   f_add(INT2FIX(m_sec(dat)),
			 m_sf_in_sec(dat)),
		   INT2FIX(m_of(dat)));
	return t;
    }
}


date_to_time(VALUE self)
{
    get_d1a(self);

    if (m_julian_p(adat)) {
        VALUE tmp = d_lite_gregorian(self);
        get_d1b(tmp);
        adat = bdat;
    }

    return f_local3(rb_cTime,
        m_real_year(adat),
        INT2FIX(m_mon(adat)),
        INT2FIX(m_mday(adat)));
}


d_lite_cmp(VALUE self, VALUE other)
{
    if (!k_date_p(other))
	return cmp_gen(self, other);

    {
	get_d2(self, other);

	if (!(simple_dat_p(adat) && simple_dat_p(bdat) &&
	      m_gregorian_p(adat) == m_gregorian_p(bdat)))
	    return cmp_dd(self, other);

	{
	    VALUE a_nth, b_nth;
	    int a_jd, b_jd;

	    m_canonicalize_jd(self, adat);
	    m_canonicalize_jd(other, bdat);
	    a_nth = m_nth(adat);
	    b_nth = m_nth(bdat);
	    if (f_eqeq_p(a_nth, b_nth)) {
		a_jd = m_jd(adat);
		b_jd = m_jd(bdat);
		if (a_jd == b_jd) {
		    return INT2FIX(0);
		}
		else if (a_jd < b_jd) {
		    return INT2FIX(-1);
		}
		else {
		    return INT2FIX(1);
		}
	    }
	    else if (f_lt_p(a_nth, b_nth)) {
		return INT2FIX(-1);
	    }
	    else {
		return INT2FIX(1);
	    }
	}
    }
}


jd_local_to_utc(int jd, int df, int of)
{
    df -= of;
    if (df < 0)
	jd -= 1;
    else if (df >= DAY_IN_SECONDS)
	jd += 1;
    return jd;
}


d_lite_gc_mark(void *ptr)
{
    union DateData *dat = ptr;
    if (simple_dat_p(dat))
	rb_gc_mark(dat->s.nth);
    else {
	rb_gc_mark(dat->c.nth);
	rb_gc_mark(dat->c.sf);
    }
}


test_nth_kday(int from, int to, double sg)
{
    int j;

    fprintf(stderr, "test_nth_kday: %d...%d (%d) - %.0f\n",
	    from, to, to - from, sg);
    for (j = from; j <= to; j++) {
	int y, m, n, k, rj, ns;

	c_jd_to_nth_kday(j, sg, &y, &m, &n, &k);
	c_nth_kday_to_jd(y, m, n, k, sg, &rj, &ns);
	if (j != rj) {
	    fprintf(stderr, "%d != %d\n", j, rj);
	    return 0;
	}
    }
    return 1;
}


m_cwyear(union DateData *x)
{
    int ry, rw, rd;

    c_jd_to_commercial(m_local_jd(x), m_virtual_sg(x), /* !=m_sg() */
		       &ry, &rw, &rd);
    return ry;
}


date_s_zone_to_diff(VALUE klass, VALUE str)
{
    return date_zone_to_diff(str);
}


date_s_test_ordinal(VALUE klass)
{
    if (!test_ordinal(MIN_JD, MIN_JD + 366, GREGORIAN))
	return Qfalse;
    if (!test_ordinal(2305814, 2598007, GREGORIAN))
	return Qfalse;
    if (!test_ordinal(MAX_JD - 366, MAX_JD, GREGORIAN))
	return Qfalse;

    if (!test_ordinal(MIN_JD, MIN_JD + 366, ITALY))
	return Qfalse;
    if (!test_ordinal(2305814, 2598007, ITALY))
	return Qfalse;
    if (!test_ordinal(MAX_JD - 366, MAX_JD, ITALY))
	return Qfalse;

    return Qtrue;
}


test_unit_v2v_iter(VALUE (* conv1)(VALUE),
		   VALUE (* conv2)(VALUE))
{
    if (!test_unit_v2v_iter2(conv1, conv2))
	return 0;
    if (!test_unit_v2v_iter2(conv2, conv1))
	return 0;
    return 1;
}


date_initialize(int argc, VALUE *argv, VALUE self)
{
    VALUE vy, vm, vd, vsg, y, fr, fr2, ret;
    int m, d;
    double sg;
    struct SimpleDateData *dat = rb_check_typeddata(self, &d_lite_type);

    if (!simple_dat_p(dat)) {
	rb_raise(rb_eTypeError, "Date expected");
    }

    rb_scan_args(argc, argv, "04", &vy, &vm, &vd, &vsg);

    y = INT2FIX(-4712);
    m = 1;
    d = 1;
    fr2 = INT2FIX(0);
    sg = DEFAULT_SG;

    switch (argc) {
      case 4:
	val2sg(vsg, sg);
      case 3:
        check_numeric(vd, "day");
	num2int_with_frac(d, positive_inf);
      case 2:
        check_numeric(vm, "month");
	m = NUM2INT(vm);
      case 1:
        check_numeric(vy, "year");
	y = vy;
    }

    if (guess_style(y, sg) < 0) {
	VALUE nth;
	int ry, rm, rd;

	if (!valid_gregorian_p(y, m, d,
			       &nth, &ry,
			       &rm, &rd))
	    rb_raise(eDateError, "invalid date");

	set_to_simple(self, dat, nth, 0, sg, ry, rm, rd, HAVE_CIVIL);
    }
    else {
	VALUE nth;
	int ry, rm, rd, rjd, ns;

	if (!valid_civil_p(y, m, d, sg,
			   &nth, &ry,
			   &rm, &rd, &rjd,
			   &ns))
	    rb_raise(eDateError, "invalid date");

	set_to_simple(self, dat, nth, rjd, sg, ry, rm, rd, HAVE_JD | HAVE_CIVIL);
    }
    ret = self;
    add_frac();
    return ret;
}


get_c_df(union DateData *x)
{
    assert(complex_dat_p(x));
    if (!have_df_p(x)) {
	assert(have_time_p(x));
#ifndef USE_PACK
	x->c.df = df_local_to_utc(time_to_df(x->c.hour, x->c.min, x->c.sec),
				  x->c.of);
#else
	x->c.df = df_local_to_utc(time_to_df(EX_HOUR(x->c.pc),
					     EX_MIN(x->c.pc),
					     EX_SEC(x->c.pc)),
				  x->c.of);
#endif
	x->c.flags |= HAVE_DF;
    }
}


tmx_m_of(union DateData *x)
{
    return m_of(x);
}


get_c_civil(union DateData *x)
{
    assert(complex_dat_p(x));
    if (!have_civil_p(x)) {
#ifndef USE_PACK
	int jd, y, m, d;
#else
	int jd, y, m, d, h, min, s;
#endif

	assert(have_jd_p(x));
	get_c_df(x);
	jd = jd_utc_to_local(x->c.jd, x->c.df, x->c.of);
	c_jd_to_civil(jd, c_virtual_sg(x), &y, &m, &d);
	x->c.year = y;
#ifndef USE_PACK
	x->c.mon = m;
	x->c.mday = d;
#else
	h = EX_HOUR(x->c.pc);
	min = EX_MIN(x->c.pc);
	s = EX_SEC(x->c.pc);
	x->c.pc = PACK5(m, d, h, min, s);
#endif
	x->c.flags |= HAVE_CIVIL;
    }
}


dt_lite_iso8601(int argc, VALUE *argv, VALUE self)
{
    long n = 0;

    rb_check_arity(argc, 0, 1);
    if (argc >= 1)
	n = NUM2LONG(argv[0]);

    return rb_str_append(strftimev("%Y-%m-%d", self, set_tmx),
			 iso8601_timediv(self, n));
}


valid_civil_p(VALUE y, int m, int d, double sg,
	      VALUE *nth, int *ry,
	      int *rm, int *rd, int *rjd,
	      int *ns)
{
    double style = guess_style(y, sg);
    int r;

    if (style == 0) {
	int jd;

	r = c_valid_civil_p(FIX2INT(y), m, d, sg, rm, rd, &jd, ns);
	if (!r)
	    return 0;
	decode_jd(INT2FIX(jd), nth, rjd);
	if (f_zero_p(*nth))
	    *ry = FIX2INT(y);
	else {
	    VALUE nth2;
	    decode_year(y, *ns ? -1 : +1, &nth2, ry);
	}
    }
    else {
	decode_year(y, style, nth, ry);
	if (style < 0)
	    r = c_valid_gregorian_p(*ry, m, d, rm, rd);
	else
	    r = c_valid_julian_p(*ry, m, d, rm, rd);
	if (!r)
	    return 0;
	c_civil_to_jd(*ry, *rm, *rd, style, rjd, ns);
    }
    return r;
}


datetime_s_rfc3339(int argc, VALUE *argv, VALUE klass)
{
    VALUE str, sg, opt;

    rb_scan_args(argc, argv, "02:", &str, &sg, &opt);
    if (!NIL_P(opt)) argc--;

    switch (argc) {
      case 0:
	str = rb_str_new2("-4712-01-01T00:00:00+00:00");
      case 1:
	sg = INT2FIX(DEFAULT_SG);
    }

    {
        int argc2 = 1;
        VALUE argv2[2];
        argv2[0] = str;
        argv2[1] = opt;
        if (!NIL_P(opt)) argc2++;
	VALUE hash = date_s__rfc3339(argc2, argv2, klass);
	return dt_new_by_frags(klass, hash, sg);
    }
}


m_sec(union DateData *x)
{
    if (simple_dat_p(x))
	return 0;
    else {
	get_c_time(x);
#ifndef USE_PACK
	return x->c.sec;
#else
	return EX_SEC(x->c.pc);
#endif
    }
}


jd_to_weeknum(VALUE jd, int f, double sg,
	      VALUE *nth, int *rjd,
	      int *ry, int *rw, int *rd)
{
    decode_jd(jd, nth, rjd);
    c_jd_to_weeknum(*rjd, f, sg, ry, rw, rd);
}


m_hour(union DateData *x)
{
    if (simple_dat_p(x))
	return 0;
    else {
	get_c_time(x);
#ifndef USE_PACK
	return x->c.hour;
#else
	return EX_HOUR(x->c.pc);
#endif
    }
}


jd_to_civil(VALUE jd, double sg,
	    VALUE *nth, int *rjd,
	    int *ry, int *rm, int *rd)
{
    decode_jd(jd, nth, rjd);
    c_jd_to_civil(*rjd, sg, ry, rm, rd);
}


d_lite_wednesday_p(VALUE self)
{
    get_d1(self);
    return f_boolcast(m_wday(dat) == 3);
}


date_s_gregorian_leap_p(VALUE klass, VALUE y)
{
    VALUE nth;
    int ry;

    check_numeric(y, "year");
    decode_year(y, -1, &nth, &ry);
    return f_boolcast(c_gregorian_leap_p(ry));
}


datetime_s_rfc2822(int argc, VALUE *argv, VALUE klass)
{
    VALUE str, sg, opt;

    rb_scan_args(argc, argv, "02:", &str, &sg, &opt);
    if (!NIL_P(opt)) argc--;

    switch (argc) {
      case 0:
	str = rb_str_new2("Mon, 1 Jan -4712 00:00:00 +0000");
      case 1:
	sg = INT2FIX(DEFAULT_SG);
    }

    {
        int argc2 = 1;
        VALUE argv2[2];
        argv2[0] = str;
        argv2[1] = opt;
        if (!NIL_P(opt)) argc2++;
	VALUE hash = date_s__rfc2822(argc2, argv2, klass);
	return dt_new_by_frags(klass, hash, sg);
    }
}


day_to_sec(VALUE d)
{
    if (safe_mul_p(d, DAY_IN_SECONDS))
	return LONG2FIX(FIX2LONG(d) * DAY_IN_SECONDS);
    return f_mul(d, INT2FIX(DAY_IN_SECONDS));
}


date_s_civil(int argc, VALUE *argv, VALUE klass)
{
    return date_initialize(argc, argv, d_lite_s_alloc_simple(klass));
}


datetime_s_now(int argc, VALUE *argv, VALUE klass)
{
    VALUE vsg, nth, ret;
    double sg;
#ifdef HAVE_CLOCK_GETTIME
    struct timespec ts;
#else
    struct timeval tv;
#endif
    time_t sec;
    struct tm tm;
    long sf, of;
    int y, ry, m, d, h, min, s;

    rb_scan_args(argc, argv, "01", &vsg);

    if (argc < 1)
	sg = DEFAULT_SG;
    else
	sg = NUM2DBL(vsg);

#ifdef HAVE_CLOCK_GETTIME
    if (clock_gettime(CLOCK_REALTIME, &ts) == -1)
	rb_sys_fail("clock_gettime");
    sec = ts.tv_sec;
#else
    if (gettimeofday(&tv, NULL) == -1)
	rb_sys_fail("gettimeofday");
    sec = tv.tv_sec;
#endif
    tzset();
    if (!localtime_r(&sec, &tm))
	rb_sys_fail("localtime");

    y = tm.tm_year + 1900;
    m = tm.tm_mon + 1;
    d = tm.tm_mday;
    h = tm.tm_hour;
    min = tm.tm_min;
    s = tm.tm_sec;
    if (s == 60)
	s = 59;
#ifdef HAVE_STRUCT_TM_TM_GMTOFF
    of = tm.tm_gmtoff;
#elif defined(HAVE_TIMEZONE)
#if defined(HAVE_ALTZONE) && !defined(_AIX)
    of = (long)-((tm.tm_isdst > 0) ? altzone : timezone);
#else
    of = (long)-timezone;
    if (tm.tm_isdst) {
	time_t sec2;

	tm.tm_isdst = 0;
	sec2 = mktime(&tm);
	of += (long)difftime(sec2, sec);
    }
#endif
#elif defined(HAVE_TIMEGM)
    {
	time_t sec2;

	sec2 = timegm(&tm);
	of = (long)difftime(sec2, sec);
    }
#else
    {
	struct tm tm2;
	time_t sec2;

	if (!gmtime_r(&sec, &tm2))
	    rb_sys_fail("gmtime");
	tm2.tm_isdst = tm.tm_isdst;
	sec2 = mktime(&tm2);
	of = (long)difftime(sec, sec2);
    }
#endif
#ifdef HAVE_CLOCK_GETTIME
    sf = ts.tv_nsec;
#else
    sf = tv.tv_usec * 1000;
#endif

    if (of < -DAY_IN_SECONDS || of > DAY_IN_SECONDS) {
	of = 0;
	rb_warning("invalid offset is ignored");
    }

    decode_year(INT2FIX(y), -1, &nth, &ry);

    ret = d_complex_new_internal(klass,
				 nth, 0,
				 0, LONG2NUM(sf),
				 (int)of, GREGORIAN,
				 ry, m, d,
				 h, min, s,
				 HAVE_CIVIL | HAVE_TIME);
    {
	get_d1(ret);
	set_sg(dat, sg);
    }
    return ret;
}


wholenum_p(VALUE x)
{
    if (FIXNUM_P(x))
	return 1;
    switch (TYPE(x)) {
      case T_BIGNUM:
	return 1;
      case T_FLOAT:
	{
	    double d = RFLOAT_VALUE(x);
	    return round(d) == d;
	}
	break;
      case T_RATIONAL:
	{
	    VALUE den = rb_rational_den(x);
	    return FIXNUM_P(den) && FIX2LONG(den) == 1;
	}
	break;
    }
    return 0;
}


isec_to_day(int s)
{
    return sec_to_day(INT2FIX(s));
}


decode_jd(VALUE jd, VALUE *nth, int *rjd)
{
    *nth = f_idiv(jd, INT2FIX(CM_PERIOD));
    if (f_zero_p(*nth)) {
	*rjd = FIX2INT(jd);
	return;
    }
    *rjd = FIX2INT(f_mod(jd, INT2FIX(CM_PERIOD)));
}


d_lite_next_year(int argc, VALUE *argv, VALUE self)
{
    VALUE n;

    rb_scan_args(argc, argv, "01", &n);
    if (argc < 1)
	n = INT2FIX(1);
    return d_lite_rshift(self, f_mul(n, INT2FIX(12)));
}


m_ajd(union DateData *x)
{
    VALUE r, sf;
    int df;

    if (simple_dat_p(x)) {
	r = m_real_jd(x);
	if (FIXNUM_P(r) && FIX2LONG(r) <= (FIXNUM_MAX / 2)) {
	    long ir = FIX2LONG(r);
	    ir = ir * 2 - 1;
	    return rb_rational_new2(LONG2FIX(ir), INT2FIX(2));
	}
	else
	    return rb_rational_new2(f_sub(f_mul(r,
						INT2FIX(2)),
					  INT2FIX(1)),
				    INT2FIX(2));
    }

    r = m_real_jd(x);
    df = m_df(x);
    df -= HALF_DAYS_IN_SECONDS;
    if (df)
	r = f_add(r, isec_to_day(df));
    sf = m_sf(x);
    if (f_nonzero_p(sf))
	r = f_add(r, ns_to_day(sf));

    return r;
}


f_le_p(VALUE x, VALUE y)
{
    if (FIXNUM_P(x) && FIXNUM_P(y))
	return f_boolcast(FIX2LONG(x) <= FIX2LONG(y));
    return rb_funcall(x, id_le_p, 1, y);
}


m_wnum1(union DateData *x)
{
    return m_wnumx(x, 1);
}


m_sf(union DateData *x)
{
    if (simple_dat_p(x))
	return INT2FIX(0);
    else
	return x->c.sf;
}


datetime_s_weeknum(int argc, VALUE *argv, VALUE klass)
{
    VALUE vy, vw, vd, vf, vh, vmin, vs, vof, vsg, y, fr, fr2, ret;
    int w, d, f, h, min, s, rof;
    double sg;

    rb_scan_args(argc, argv, "09", &vy, &vw, &vd, &vf,
		 &vh, &vmin, &vs, &vof, &vsg);

    y = INT2FIX(-4712);
    w = 0;
    d = 1;
    f = 0;

    h = min = s = 0;
    fr2 = INT2FIX(0);
    rof = 0;
    sg = DEFAULT_SG;

    switch (argc) {
      case 9:
	val2sg(vsg, sg);
      case 8:
	val2off(vof, rof);
      case 7:
	num2int_with_frac(s, positive_inf);
      case 6:
	num2int_with_frac(min, 6);
      case 5:
	num2int_with_frac(h, 5);
      case 4:
	f = NUM2INT(vf);
      case 3:
	num2int_with_frac(d, 4);
      case 2:
	w = NUM2INT(vw);
      case 1:
	y = vy;
    }

    {
	VALUE nth;
	int ry, rw, rd, rh, rmin, rs, rjd, rjd2, ns;

	if (!valid_weeknum_p(y, w, d, f, sg,
			     &nth, &ry,
			     &rw, &rd, &rjd,
			     &ns))
	    rb_raise(eDateError, "invalid date");
	if (!c_valid_time_p(h, min, s, &rh, &rmin, &rs))
	    rb_raise(eDateError, "invalid date");
	canon24oc();

	rjd2 = jd_local_to_utc(rjd,
			       time_to_df(rh, rmin, rs),
			       rof);
	ret = d_complex_new_internal(klass,
				     nth, rjd2,
				     0, INT2FIX(0),
				     rof, sg,
				     0, 0, 0,
				     rh, rmin, rs,
				     HAVE_JD | HAVE_TIME);
    }
    add_frac();
    return ret;
}


set_sg(union DateData *x, double sg)
{
    if (simple_dat_p(x)) {
	get_s_jd(x);
	clear_civil(x);
	x->s.sg = (date_sg_t)sg;
    } else {
	get_c_jd(x);
	get_c_df(x);
	clear_civil(x);
	x->c.sg = (date_sg_t)sg;
    }
}


d_lite_gregorian(VALUE self)
{
    return dup_obj_with_new_start(self, GREGORIAN);
}


div_df(VALUE d, VALUE *f)
{
    VALUE s = day_to_sec(d);

    if (f)
	*f = f_mod(s, INT2FIX(1));
    return f_floor(s);
}


d_lite_amjd(VALUE self)
{
    get_d1(self);
    return m_amjd(dat);
}


m_sf_in_sec(union DateData *x)
{
    return ns_to_sec(m_sf(x));
}


canonicalize_c_jd(VALUE obj, union DateData *x)
{
    int j = x->c.jd;
    VALUE nth = x->c.nth;
    assert(have_jd_p(x));
    canonicalize_jd(nth, x->c.jd);
    RB_OBJ_WRITE(obj, &x->c.nth, nth);
    if (x->c.jd != j)
	x->flags &= ~HAVE_CIVIL;
}


d_lite_sec_fraction(VALUE self)
{
    get_d1(self);
    return m_sf_in_sec(dat);
}


d_lite_new_start(int argc, VALUE *argv, VALUE self)
{
    VALUE vsg;
    double sg;

    rb_scan_args(argc, argv, "01", &vsg);

    sg = DEFAULT_SG;
    if (argc >= 1)
	val2sg(vsg, sg);

    return dup_obj_with_new_start(self, sg);
}


c_jd_to_commercial(int jd, double sg, int *ry, int *rw, int *rd)
{
    int ry2, rm2, rd2, a, rjd2, ns2;

    c_jd_to_civil(jd - 3, sg, &ry2, &rm2, &rd2);
    a = ry2;
    c_commercial_to_jd(a + 1, 1, 1, sg, &rjd2, &ns2);
    if (jd >= rjd2)
	*ry = a + 1;
    else {
	c_commercial_to_jd(a, 1, 1, sg, &rjd2, &ns2);
	*ry = a;
    }
    *rw = 1 + DIV(jd - rjd2, 7);
    *rd = MOD(jd + 1, 7);
    if (*rd == 0)
	*rd = 7;
}


date_s_jisx0301(int argc, VALUE *argv, VALUE klass)
{
    VALUE str, sg, opt;

    rb_scan_args(argc, argv, "02:", &str, &sg, &opt);
    if (!NIL_P(opt)) argc--;

    switch (argc) {
      case 0:
	str = rb_str_new2("-4712-01-01");
      case 1:
	sg = INT2FIX(DEFAULT_SG);
    }

    {
        int argc2 = 1;
        VALUE argv2[2];
        argv2[0] = str;
        if (!NIL_P(opt)) argv2[argc2++] = opt;
	VALUE hash = date_s__jisx0301(argc2, argv2, klass);
	return d_new_by_frags(klass, hash, sg);
    }
}


date_s_ordinal(int argc, VALUE *argv, VALUE klass)
{
    VALUE vy, vd, vsg, y, fr, fr2, ret;
    int d;
    double sg;

    rb_scan_args(argc, argv, "03", &vy, &vd, &vsg);

    y = INT2FIX(-4712);
    d = 1;
    fr2 = INT2FIX(0);
    sg = DEFAULT_SG;

    switch (argc) {
      case 3:
	val2sg(vsg, sg);
      case 2:
        check_numeric(vd, "yday");
	num2int_with_frac(d, positive_inf);
      case 1:
        check_numeric(vy, "year");
	y = vy;
    }

    {
	VALUE nth;
	int ry, rd, rjd, ns;

	if (!valid_ordinal_p(y, d, sg,
			     &nth, &ry,
			     &rd, &rjd,
			     &ns))
	    rb_raise(eDateError, "invalid date");

	ret = d_simple_new_internal(klass,
				     nth, rjd,
				     sg,
				     0, 0, 0,
				     HAVE_JD);
    }
    add_frac();
    return ret;
}


m_local_jd(union DateData *x)
{
    if (simple_dat_p(x)) {
	get_s_jd(x);
	return x->s.jd;
    }
    else {
	get_c_jd(x);
	get_c_df(x);
	return local_jd(x);
    }
}


c_nth_kday_to_jd(int y, int m, int n, int k, double sg, int *rjd, int *ns)
{
    int rjd2, ns2;

    if (n > 0) {
	c_find_fdom(y, m, sg, &rjd2, &ns2);
	rjd2 -= 1;
    }
    else {
	c_find_ldom(y, m, sg, &rjd2, &ns2);
	rjd2 += 7;
    }
    *rjd = (rjd2 - MOD((rjd2 - k) + 1, 7)) + 7 * n;
    *ns = (*rjd < sg) ? 0 : 1;
}


d_lite_s_alloc_complex(VALUE klass)
{
    return d_complex_new_internal(klass,
				  INT2FIX(0), 0,
				  0, INT2FIX(0),
				  0, DEFAULT_SG,
				  0, 0, 0,
				  0, 0, 0,
				  HAVE_JD | HAVE_DF);
}


valid_gregorian_p(VALUE y, int m, int d,
		  VALUE *nth, int *ry,
		  int *rm, int *rd)
{
    decode_year(y, -1, nth, ry);
    return c_valid_gregorian_p(*ry, m, d, rm, rd);
}


date_s__rfc2822(int argc, VALUE *argv, VALUE klass)
{
    VALUE str, opt;

    rb_scan_args(argc, argv, "1:", &str, &opt);
    check_limit(str, opt);

    return date__rfc2822(str);
}


valid_jd_sub(int argc, VALUE *argv, VALUE klass, int need_jd)
{
    double sg = NUM2DBL(argv[1]);
    valid_sg(sg);
    return argv[0];
}


date_s__iso8601(int argc, VALUE *argv, VALUE klass)
{
    VALUE str, opt;

    rb_scan_args(argc, argv, "1:", &str, &opt);
    check_limit(str, opt);

    return date__iso8601(str);
}


m_gregorian_p(union DateData *x)
{
    return !m_julian_p(x);
}


d_lite_prev_year(int argc, VALUE *argv, VALUE self)
{
    VALUE n;

    rb_scan_args(argc, argv, "01", &n);
    if (argc < 1)
	n = INT2FIX(1);
    return d_lite_lshift(self, f_mul(n, INT2FIX(12)));
}


c_julian_leap_p(int y)
{
    return MOD(y, 4) == 0;
}


d_lite_offset(VALUE self)
{
    get_d1(self);
    return m_of_in_day(dat);
}


date_s__valid_weeknum_p(int argc, VALUE *argv, VALUE klass)
{
    VALUE vy, vw, vd, vf, vsg;
    VALUE argv2[5];

    rb_scan_args(argc, argv, "41", &vy, &vw, &vd, &vf, &vsg);

    argv2[0] = vy;
    argv2[1] = vw;
    argv2[2] = vd;
    argv2[3] = vf;
    if (argc < 5)
	argv2[4] = DBL2NUM(GREGORIAN);
    else
	argv2[4] = vsg;

    return valid_weeknum_sub(5, argv2, klass, 1);
}


d_lite_plus(VALUE self, VALUE other)
{
    int try_rational = 1;
    get_d1(self);

  again:
    switch (TYPE(other)) {
      case T_FIXNUM:
	{
	    VALUE nth;
	    long t;
	    int jd;

	    nth = m_nth(dat);
	    t = FIX2LONG(other);
	    if (DIV(t, CM_PERIOD)) {
		nth = f_add(nth, INT2FIX(DIV(t, CM_PERIOD)));
		t = MOD(t, CM_PERIOD);
	    }

	    if (!t)
		jd = m_jd(dat);
	    else {
		jd = m_jd(dat) + (int)t;
		canonicalize_jd(nth, jd);
	    }

	    if (simple_dat_p(dat))
		return d_simple_new_internal(rb_obj_class(self),
					     nth, jd,
					     dat->s.sg,
					     0, 0, 0,
					     (dat->s.flags | HAVE_JD) &
					     ~HAVE_CIVIL);
	    else
		return d_complex_new_internal(rb_obj_class(self),
					      nth, jd,
					      dat->c.df, dat->c.sf,
					      dat->c.of, dat->c.sg,
					      0, 0, 0,
#ifndef USE_PACK
					      dat->c.hour,
					      dat->c.min,
					      dat->c.sec,
#else
					      EX_HOUR(dat->c.pc),
					      EX_MIN(dat->c.pc),
					      EX_SEC(dat->c.pc),
#endif
					      (dat->c.flags | HAVE_JD) &
					      ~HAVE_CIVIL);
	}
	break;
      case T_BIGNUM:
	{
	    VALUE nth;
	    int jd, s;

	    if (f_positive_p(other))
		s = +1;
	    else {
		s = -1;
		other = f_negate(other);
	    }

	    nth = f_idiv(other, INT2FIX(CM_PERIOD));
	    jd = FIX2INT(f_mod(other, INT2FIX(CM_PERIOD)));

	    if (s < 0) {
		nth = f_negate(nth);
		jd = -jd;
	    }

	    if (!jd)
		jd = m_jd(dat);
	    else {
		jd = m_jd(dat) + jd;
		canonicalize_jd(nth, jd);
	    }

	    if (f_zero_p(nth))
		nth = m_nth(dat);
	    else
		nth = f_add(m_nth(dat), nth);

	    if (simple_dat_p(dat))
		return d_simple_new_internal(rb_obj_class(self),
					     nth, jd,
					     dat->s.sg,
					     0, 0, 0,
					     (dat->s.flags | HAVE_JD) &
					     ~HAVE_CIVIL);
	    else
		return d_complex_new_internal(rb_obj_class(self),
					      nth, jd,
					      dat->c.df, dat->c.sf,
					      dat->c.of, dat->c.sg,
					      0, 0, 0,
#ifndef USE_PACK
					      dat->c.hour,
					      dat->c.min,
					      dat->c.sec,
#else
					      EX_HOUR(dat->c.pc),
					      EX_MIN(dat->c.pc),
					      EX_SEC(dat->c.pc),
#endif
					      (dat->c.flags | HAVE_JD) &
					      ~HAVE_CIVIL);
	}
	break;
      case T_FLOAT:
	{
	    double jd, o, tmp;
	    int s, df;
	    VALUE nth, sf;

	    o = RFLOAT_VALUE(other);

	    if (o > 0)
		s = +1;
	    else {
		s = -1;
		o = -o;
	    }

	    o = modf(o, &tmp);

	    if (!floor(tmp / CM_PERIOD)) {
		nth = INT2FIX(0);
		jd = (int)tmp;
	    }
	    else {
		double i, f;

		f = modf(tmp / CM_PERIOD, &i);
		nth = f_floor(DBL2NUM(i));
		jd = (int)(f * CM_PERIOD);
	    }

	    o *= DAY_IN_SECONDS;
	    o = modf(o, &tmp);
	    df = (int)tmp;
	    o *= SECOND_IN_NANOSECONDS;
	    sf = INT2FIX((int)round(o));

	    if (s < 0) {
		jd = -jd;
		df = -df;
		sf = f_negate(sf);
	    }

	    if (f_zero_p(sf))
		sf = m_sf(dat);
	    else {
		sf = f_add(m_sf(dat), sf);
		if (f_lt_p(sf, INT2FIX(0))) {
		    df -= 1;
		    sf = f_add(sf, INT2FIX(SECOND_IN_NANOSECONDS));
		}
		else if (f_ge_p(sf, INT2FIX(SECOND_IN_NANOSECONDS))) {
		    df += 1;
		    sf = f_sub(sf, INT2FIX(SECOND_IN_NANOSECONDS));
		}
	    }

	    if (!df)
		df = m_df(dat);
	    else {
		df = m_df(dat) + df;
		if (df < 0) {
		    jd -= 1;
		    df += DAY_IN_SECONDS;
		}
		else if (df >= DAY_IN_SECONDS) {
		    jd += 1;
		    df -= DAY_IN_SECONDS;
		}
	    }

	    if (!jd)
		jd = m_jd(dat);
	    else {
		jd = m_jd(dat) + jd;
		canonicalize_jd(nth, jd);
	    }

	    if (f_zero_p(nth))
		nth = m_nth(dat);
	    else
		nth = f_add(m_nth(dat), nth);

	    if (!df && f_zero_p(sf) && !m_of(dat))
		return d_simple_new_internal(rb_obj_class(self),
					     nth, (int)jd,
					     m_sg(dat),
					     0, 0, 0,
					     (dat->s.flags | HAVE_JD) &
					     ~(HAVE_CIVIL | HAVE_TIME |
					       COMPLEX_DAT));
	    else
		return d_complex_new_internal(rb_obj_class(self),
					      nth, (int)jd,
					      df, sf,
					      m_of(dat), m_sg(dat),
					      0, 0, 0,
					      0, 0, 0,
					      (dat->c.flags |
					       HAVE_JD | HAVE_DF) &
					      ~(HAVE_CIVIL | HAVE_TIME));
	}
	break;
      default:
	expect_numeric(other);
	other = f_to_r(other);
	if (!k_rational_p(other)) {
	    if (!try_rational) Check_Type(other, T_RATIONAL);
	    try_rational = 0;
	    goto again;
	}
	/* fall through */
      case T_RATIONAL:
	{
	    VALUE nth, sf, t;
	    int jd, df, s;

	    if (wholenum_p(other)) {
		other = rb_rational_num(other);
		goto again;
	    }

	    if (f_positive_p(other))
		s = +1;
	    else {
		s = -1;
		other = f_negate(other);
	    }

	    nth = f_idiv(other, INT2FIX(CM_PERIOD));
	    t = f_mod(other, INT2FIX(CM_PERIOD));

	    jd = FIX2INT(f_idiv(t, INT2FIX(1)));
	    t = f_mod(t, INT2FIX(1));

	    t = f_mul(t, INT2FIX(DAY_IN_SECONDS));
	    df = FIX2INT(f_idiv(t, INT2FIX(1)));
	    t = f_mod(t, INT2FIX(1));

	    sf = f_mul(t, INT2FIX(SECOND_IN_NANOSECONDS));

	    if (s < 0) {
		nth = f_negate(nth);
		jd = -jd;
		df = -df;
		sf = f_negate(sf);
	    }

	    if (f_zero_p(sf))
		sf = m_sf(dat);
	    else {
		sf = f_add(m_sf(dat), sf);
		if (f_lt_p(sf, INT2FIX(0))) {
		    df -= 1;
		    sf = f_add(sf, INT2FIX(SECOND_IN_NANOSECONDS));
		}
		else if (f_ge_p(sf, INT2FIX(SECOND_IN_NANOSECONDS))) {
		    df += 1;
		    sf = f_sub(sf, INT2FIX(SECOND_IN_NANOSECONDS));
		}
	    }

	    if (!df)
		df = m_df(dat);
	    else {
		df = m_df(dat) + df;
		if (df < 0) {
		    jd -= 1;
		    df += DAY_IN_SECONDS;
		}
		else if (df >= DAY_IN_SECONDS) {
		    jd += 1;
		    df -= DAY_IN_SECONDS;
		}
	    }

	    if (!jd)
		jd = m_jd(dat);
	    else {
		jd = m_jd(dat) + jd;
		canonicalize_jd(nth, jd);
	    }

	    if (f_zero_p(nth))
		nth = m_nth(dat);
	    else
		nth = f_add(m_nth(dat), nth);

	    if (!df && f_zero_p(sf) && !m_of(dat))
		return d_simple_new_internal(rb_obj_class(self),
					     nth, jd,
					     m_sg(dat),
					     0, 0, 0,
					     (dat->s.flags | HAVE_JD) &
					     ~(HAVE_CIVIL | HAVE_TIME |
					       COMPLEX_DAT));
	    else
		return d_complex_new_internal(rb_obj_class(self),
					      nth, jd,
					      df, sf,
					      m_of(dat), m_sg(dat),
					      0, 0, 0,
					      0, 0, 0,
					      (dat->c.flags |
					       HAVE_JD | HAVE_DF) &
					      ~(HAVE_CIVIL | HAVE_TIME));
	}
	break;
    }
}


m_of(union DateData *x)
{
    if (simple_dat_p(x))
	return 0;
    else {
	get_c_jd(x);
	return x->c.of;
    }
}


encode_jd(VALUE nth, int jd, VALUE *rjd)
{
    if (f_zero_p(nth)) {
	*rjd = INT2FIX(jd);
	return;
    }
    *rjd = f_add(f_mul(INT2FIX(CM_PERIOD), nth), INT2FIX(jd));
}


d_new_by_frags(VALUE klass, VALUE hash, VALUE sg)
{
    VALUE jd;

    if (!c_valid_start_p(NUM2DBL(sg))) {
	sg = INT2FIX(DEFAULT_SG);
	rb_warning("invalid start is ignored");
    }

    if (NIL_P(hash))
	rb_raise(eDateError, "invalid date");

    if (NIL_P(ref_hash("jd")) &&
	NIL_P(ref_hash("yday")) &&
	!NIL_P(ref_hash("year")) &&
	!NIL_P(ref_hash("mon")) &&
	!NIL_P(ref_hash("mday")))
	jd = rt__valid_civil_p(ref_hash("year"),
			       ref_hash("mon"),
			       ref_hash("mday"), sg);
    else {
	hash = rt_rewrite_frags(hash);
	hash = rt_complete_frags(klass, hash);
	jd = rt__valid_date_frags_p(hash, sg);
    }

    if (NIL_P(jd))
	rb_raise(eDateError, "invalid date");
    {
	VALUE nth;
	int rjd;

	decode_jd(jd, &nth, &rjd);
	return d_simple_new_internal(klass,
				     nth, rjd,
				     NUM2DBL(sg),
				     0, 0, 0,
				     HAVE_JD);
    }
}


m_real_local_jd(union DateData *x)
{
    VALUE nth, rjd;
    int jd;

    nth = m_nth(x);
    jd = m_local_jd(x);

    encode_jd(nth, jd, &rjd);
    return rjd;
}


rt__valid_commercial_p(VALUE y, VALUE w, VALUE d, VALUE sg)
{
    VALUE nth, rjd2;
    int ry, rw, rd, rjd, ns;

    if (!valid_commercial_p(y, NUM2INT(w), NUM2INT(d), NUM2DBL(sg),
			    &nth, &ry,
			    &rw, &rd, &rjd,
			    &ns))
	return Qnil;
    encode_jd(nth, rjd, &rjd2);
    return rjd2;
}


date_s__valid_civil_p(int argc, VALUE *argv, VALUE klass)
{
    VALUE vy, vm, vd, vsg;
    VALUE argv2[4];

    rb_scan_args(argc, argv, "31", &vy, &vm, &vd, &vsg);

    argv2[0] = vy;
    argv2[1] = vm;
    argv2[2] = vd;
    if (argc < 4)
	argv2[3] = DBL2NUM(GREGORIAN);
    else
	argv2[3] = vsg;

    return valid_civil_sub(4, argv2, klass, 1);
}


df_local_to_utc(int df, int of)
{
    df -= of;
    if (df < 0)
	df += DAY_IN_SECONDS;
    else if (df >= DAY_IN_SECONDS)
	df -= DAY_IN_SECONDS;
    return df;
}


get_c_jd(union DateData *x)
{
    assert(complex_dat_p(x));
    if (!have_jd_p(x)) {
	int jd, ns;

	assert(have_civil_p(x));
#ifndef USE_PACK
	c_civil_to_jd(x->c.year, x->c.mon, x->c.mday,
		      c_virtual_sg(x), &jd, &ns);
#else
	c_civil_to_jd(x->c.year, EX_MON(x->c.pc), EX_MDAY(x->c.pc),
		      c_virtual_sg(x), &jd, &ns);
#endif

	get_c_time(x);
#ifndef USE_PACK
	x->c.jd = jd_local_to_utc(jd,
				  time_to_df(x->c.hour, x->c.min, x->c.sec),
				  x->c.of);
#else
	x->c.jd = jd_local_to_utc(jd,
				  time_to_df(EX_HOUR(x->c.pc),
					     EX_MIN(x->c.pc),
					     EX_SEC(x->c.pc)),
				  x->c.of);
#endif
	x->c.flags |= HAVE_JD;
    }
}


d_lite_friday_p(VALUE self)
{
    get_d1(self);
    return f_boolcast(m_wday(dat) == 5);
}


d_simple_new_internal(VALUE klass,
		      VALUE nth, int jd,
		      double sg,
		      int y, int m, int d,
		      unsigned flags)
{
    struct SimpleDateData *dat;
    VALUE obj;

    obj = TypedData_Make_Struct(klass, struct SimpleDateData,
				&d_lite_type, dat);
    set_to_simple(obj, dat, nth, jd, sg, y, m, d, flags);

    assert(have_jd_p(dat) || have_civil_p(dat));

    return obj;
}


tmx_m_zone(union DateData *x)
{
    VALUE zone = m_zone(x);
    /* TODO: fix potential dangling pointer */
    return RSTRING_PTR(zone);
}


d_lite_httpdate(VALUE self)
{
    volatile VALUE dup = dup_obj_with_new_offset(self, 0);
    return strftimev("%a, %d %b %Y %T GMT", dup, set_tmx);
}


d_lite_start(VALUE self)
{
    get_d1(self);
    return DBL2NUM(m_sg(dat));
}


mk_inspect(union DateData *x, VALUE klass, VALUE to_s)
{
    return rb_enc_sprintf(rb_usascii_encoding(),
			  "#<%"PRIsVALUE": %"PRIsVALUE" "
			  "((%+"PRIsVALUE"j,%ds,%+"PRIsVALUE"n),%+ds,%.0fj)>",
			  klass, to_s,
			  m_real_jd(x), m_df(x), m_sf(x),
			  m_of(x), m_sg(x));
}


dup_obj_as_complex(VALUE self)
{
    get_d1a(self);

    if (simple_dat_p(adat)) {
	VALUE new = d_lite_s_alloc_complex(rb_obj_class(self));
	{
	    get_d1b(new);
	    copy_simple_to_complex(new, &bdat->c, &adat->s);
	    bdat->c.flags |= HAVE_DF | COMPLEX_DAT;
	    return new;
	}
    }
    else {
	VALUE new = d_lite_s_alloc_complex(rb_obj_class(self));
	{
	    get_d1b(new);
	    bdat->c = adat->c;
	    RB_OBJ_WRITTEN(new, Qundef, bdat->c.nth);
	    RB_OBJ_WRITTEN(new, Qundef, bdat->c.sf);
	    return new;
	}
    }
}


d_lite_iso8601(VALUE self)
{
    return strftimev("%Y-%m-%d", self, set_tmx);
}


c_valid_weeknum_p(int y, int w, int d, int f, double sg,
		  int *rw, int *rd, int *rjd, int *ns)
{
    int ns2, ry2, rw2, rd2;

    if (d < 0)
	d += 7;
    if (w < 0) {
	int rjd2;

	c_weeknum_to_jd(y + 1, 1, f, f, sg, &rjd2, &ns2);
	c_jd_to_weeknum(rjd2 + w * 7, f, sg, &ry2, &rw2, &rd2);
	if (ry2 != y)
	    return 0;
	w = rw2;
    }
    c_weeknum_to_jd(y, w, d, f, sg, rjd, ns);
    c_jd_to_weeknum(*rjd, f, sg, &ry2, rw, rd);
    if (y != ry2 || w != *rw || d != *rd)
	return 0;
    return 1;
}


ns_to_day(VALUE n)
{
    if (FIXNUM_P(n))
	return rb_rational_new2(n, day_in_nanoseconds);
    return f_quo(n, day_in_nanoseconds);
}


d_lite_zone(VALUE self)
{
    get_d1(self);
    return m_zone(dat);
}


jd_utc_to_local(int jd, int df, int of)
{
    df += of;
    if (df < 0)
	jd -= 1;
    else if (df >= DAY_IN_SECONDS)
	jd += 1;
    return jd;
}


d_lite_s_alloc_simple(VALUE klass)
{
    return d_simple_new_internal(klass,
				 INT2FIX(0), 0,
				 DEFAULT_SG,
				 0, 0, 0,
				 HAVE_JD);
}


datetime_s_civil(int argc, VALUE *argv, VALUE klass)
{
    return datetime_initialize(argc, argv, d_lite_s_alloc_complex(klass));
}


datetime_s_xmlschema(int argc, VALUE *argv, VALUE klass)
{
    VALUE str, sg, opt;

    rb_scan_args(argc, argv, "02:", &str, &sg, &opt);
    if (!NIL_P(opt)) argc--;

    switch (argc) {
      case 0:
	str = rb_str_new2("-4712-01-01T00:00:00+00:00");
      case 1:
	sg = INT2FIX(DEFAULT_SG);
    }

    {
        int argc2 = 1;
        VALUE argv2[2];
        argv2[0] = str;
        argv2[1] = opt;
        if (!NIL_P(opt)) argc2++;
	VALUE hash = date_s__xmlschema(argc2, argv2, klass);
	return dt_new_by_frags(klass, hash, sg);
    }
}


c_commercial_to_jd(int y, int w, int d, double sg, int *rjd, int *ns)
{
    int rjd2, ns2;

    c_find_fdoy(y, sg, &rjd2, &ns2);
    rjd2 += 3;
    *rjd =
	(rjd2 - MOD((rjd2 - 1) + 1, 7)) +
	7 * (w - 1) +
	(d - 1);
    *ns = (*rjd < sg) ? 0 : 1;
}


isec_to_ns(int s)
{
    return sec_to_ns(INT2FIX(s));
}


k_rational_p(VALUE x)
{
    return f_kind_of_p(x, rb_cRational);
}


of2str(int of)
{
    int s, h, m;

    decode_offset(of, s, h, m);
    return rb_enc_sprintf(rb_usascii_encoding(), "%c%02d:%02d", s, h, m);
}


valid_weeknum_sub(int argc, VALUE *argv, VALUE klass, int need_jd)
{
    VALUE nth, y;
    int w, d, f, ry, rw, rd;
    double sg;

    y = argv[0];
    w = NUM2INT(argv[1]);
    d = NUM2INT(argv[2]);
    f = NUM2INT(argv[3]);
    sg = NUM2DBL(argv[4]);

    valid_sg(sg);

    {
	int rjd, ns;
	VALUE rjd2;

	if (!valid_weeknum_p(y, w, d, f, sg,
			     &nth, &ry,
			     &rw, &rd, &rjd,
			     &ns))
	    return Qnil;
	if (!need_jd)
	    return INT2FIX(0); /* dummy */
	encode_jd(nth, rjd, &rjd2);
	return rjd2;
    }
}


m_real_year(union DateData *x)
{
    VALUE nth, ry;
    int year;

    nth = m_nth(x);
    year = m_year(x);

    if (f_zero_p(nth))
	return INT2FIX(year);

    encode_year(nth, year,
		m_gregorian_p(x) ? -1 : +1,
		&ry);
    return ry;
}


m_mon(union DateData *x)
{
    if (simple_dat_p(x)) {
	get_s_civil(x);
#ifndef USE_PACK
	return x->s.mon;
#else
	return EX_MON(x->s.pc);
#endif
    }
    else {
	get_c_civil(x);
#ifndef USE_PACK
	return x->c.mon;
#else
	return EX_MON(x->c.pc);
#endif
    }
}


s_trunc(VALUE s, VALUE *fr)
{
    VALUE rs;

    if (wholenum_p(s)) {
	rs = to_integer(s);
	*fr = INT2FIX(0);
    }
    else {
	rs = f_idiv(s, INT2FIX(1));
	*fr = f_mod(s, INT2FIX(1));
	*fr = f_quo(*fr, INT2FIX(86400));
    }
    return rs;
}


jd_to_ordinal(VALUE jd, double sg,
	      VALUE *nth, int *rjd,
	      int *ry, int *rd)
{
    decode_jd(jd, nth, rjd);
    c_jd_to_ordinal(*rjd, sg, ry, rd);
}


jd_to_nth_kday(VALUE jd, double sg,
	       VALUE *nth, int *rjd,
	       int *ry, int *rm, int *rn, int *rk)
{
    decode_jd(jd, nth, rjd);
    c_jd_to_nth_kday(*rjd, sg, ry, rm, rn, rk);
}


test_civil(int from, int to, double sg)
{
    int j;

    fprintf(stderr, "test_civil: %d...%d (%d) - %.0f\n",
	    from, to, to - from, sg);
    for (j = from; j <= to; j++) {
	int y, m, d, rj, ns;

	c_jd_to_civil(j, sg, &y, &m, &d);
	c_civil_to_jd(y, m, d, sg, &rj, &ns);
	if (j != rj) {
	    fprintf(stderr, "%d != %d\n", j, rj);
	    return 0;
	}
    }
    return 1;
}


d_lite_thursday_p(VALUE self)
{
    get_d1(self);
    return f_boolcast(m_wday(dat) == 4);
}


d_lite_equal(VALUE self, VALUE other)
{
    if (!k_date_p(other))
	return equal_gen(self, other);

    {
	get_d2(self, other);

	if (!(m_gregorian_p(adat) == m_gregorian_p(bdat)))
	    return equal_gen(self, other);

	{
	    VALUE a_nth, b_nth;
	    int a_jd, b_jd;

	    m_canonicalize_jd(self, adat);
	    m_canonicalize_jd(other, bdat);
	    a_nth = m_nth(adat);
	    b_nth = m_nth(bdat);
	    a_jd = m_local_jd(adat);
	    b_jd = m_local_jd(bdat);
	    if (f_eqeq_p(a_nth, b_nth) &&
		a_jd == b_jd)
		return Qtrue;
	    return Qfalse;
	}
    }
}


s_virtual_sg(union DateData *x)
{
    if (isinf(x->s.sg))
	return x->s.sg;
    if (f_zero_p(x->s.nth))
	return x->s.sg;
    else if (f_negative_p(x->s.nth))
	return positive_inf;
    return negative_inf;
}


canonicalize_s_jd(VALUE obj, union DateData *x)
{
    int j = x->s.jd;
    VALUE nth = x->s.nth;
    assert(have_jd_p(x));
    canonicalize_jd(nth, x->s.jd);
    RB_OBJ_WRITE(obj, &x->s.nth, nth);
    if (x->s.jd != j)
	x->flags &= ~HAVE_CIVIL;
}


d_lite_cwday(VALUE self)
{
    get_d1(self);
    return INT2FIX(m_cwday(dat));
}


d_lite_italy(VALUE self)
{
    return dup_obj_with_new_start(self, ITALY);
}


datetime_to_date(VALUE self)
{
    get_d1a(self);

    if (simple_dat_p(adat)) {
	VALUE new = d_lite_s_alloc_simple(cDate);
	{
	    get_d1b(new);
	    bdat->s = adat->s;
	    bdat->s.jd = m_local_jd(adat);
	    return new;
	}
    }
    else {
	VALUE new = d_lite_s_alloc_simple(cDate);
	{
	    get_d1b(new);
	    copy_complex_to_simple(new, &bdat->s, &adat->c);
	    bdat->s.jd = m_local_jd(adat);
	    bdat->s.flags &= ~(HAVE_DF | HAVE_TIME | COMPLEX_DAT);
	    return new;
	}
    }
}


test_ordinal(int from, int to, double sg)
{
    int j;

    fprintf(stderr, "test_ordinal: %d...%d (%d) - %.0f\n",
	    from, to, to - from, sg);
    for (j = from; j <= to; j++) {
	int y, d, rj, ns;

	c_jd_to_ordinal(j, sg, &y, &d);
	c_ordinal_to_jd(y, d, sg, &rj, &ns);
	if (j != rj) {
	    fprintf(stderr, "%d != %d\n", j, rj);
	    return 0;
	}
    }
    return 1;
}


m_fr(union DateData *x)
{
    if (simple_dat_p(x))
	return INT2FIX(0);
    else {
	int df;
	VALUE sf, fr;

	df = m_local_df(x);
	sf = m_sf(x);
	fr = isec_to_day(df);
	if (f_nonzero_p(sf))
	    fr = f_add(fr, ns_to_day(sf));
	return fr;
    }
}


h_trunc(VALUE h, VALUE *fr)
{
    VALUE rh;

    if (wholenum_p(h)) {
	rh = to_integer(h);
	*fr = INT2FIX(0);
    }
    else {
	rh = f_idiv(h, INT2FIX(1));
	*fr = f_mod(h, INT2FIX(1));
	*fr = f_quo(*fr, INT2FIX(24));
    }
    return rh;
}


rt__valid_weeknum_p(VALUE y, VALUE w, VALUE d, VALUE f, VALUE sg)
{
    VALUE nth, rjd2;
    int ry, rw, rd, rjd, ns;

    if (!valid_weeknum_p(y, NUM2INT(w), NUM2INT(d), NUM2INT(f), NUM2DBL(sg),
			 &nth, &ry,
			 &rw, &rd, &rjd,
			 &ns))
	return Qnil;
    encode_jd(nth, rjd, &rjd2);
    return rjd2;
}


d_lite_monday_p(VALUE self)
{
    get_d1(self);
    return f_boolcast(m_wday(dat) == 1);
}


dt_lite_rfc3339(int argc, VALUE *argv, VALUE self)
{
    return dt_lite_iso8601(argc, argv, self);
}


sec_to_ns(VALUE s)
{
    if (safe_mul_p(s, SECOND_IN_NANOSECONDS))
	return LONG2FIX(FIX2LONG(s) * SECOND_IN_NANOSECONDS);
    return f_mul(s, INT2FIX(SECOND_IN_NANOSECONDS));
}


m_of_in_day(union DateData *x)
{
    return isec_to_day(m_of(x));
}


d_lite_saturday_p(VALUE self)
{
    get_d1(self);
    return f_boolcast(m_wday(dat) == 6);
}


datetime_s_ordinal(int argc, VALUE *argv, VALUE klass)
{
    VALUE vy, vd, vh, vmin, vs, vof, vsg, y, fr, fr2, ret;
    int d, h, min, s, rof;
    double sg;

    rb_scan_args(argc, argv, "07", &vy, &vd, &vh, &vmin, &vs, &vof, &vsg);

    y = INT2FIX(-4712);
    d = 1;

    h = min = s = 0;
    fr2 = INT2FIX(0);
    rof = 0;
    sg = DEFAULT_SG;

    switch (argc) {
      case 7:
	val2sg(vsg, sg);
      case 6:
	val2off(vof, rof);
      case 5:
        check_numeric(vs, "second");
	num2int_with_frac(s, positive_inf);
      case 4:
        check_numeric(vmin, "minute");
	num2int_with_frac(min, 4);
      case 3:
        check_numeric(vh, "hour");
	num2int_with_frac(h, 3);
      case 2:
        check_numeric(vd, "yday");
	num2int_with_frac(d, 2);
      case 1:
        check_numeric(vy, "year");
	y = vy;
    }

    {
	VALUE nth;
	int ry, rd, rh, rmin, rs, rjd, rjd2, ns;

	if (!valid_ordinal_p(y, d, sg,
			     &nth, &ry,
			     &rd, &rjd,
			     &ns))
	    rb_raise(eDateError, "invalid date");
	if (!c_valid_time_p(h, min, s, &rh, &rmin, &rs))
	    rb_raise(eDateError, "invalid date");
	canon24oc();

	rjd2 = jd_local_to_utc(rjd,
			       time_to_df(rh, rmin, rs),
			       rof);

	ret = d_complex_new_internal(klass,
				     nth, rjd2,
				     0, INT2FIX(0),
				     rof, sg,
				     0, 0, 0,
				     rh, rmin, rs,
				     HAVE_JD | HAVE_TIME);
    }
    add_frac();
    return ret;
}


dt_lite_to_s(VALUE self)
{
    return strftimev("%Y-%m-%dT%H:%M:%S%:z", self, set_tmx);
}


strftimev(const char *fmt, VALUE self,
	  void (*func)(VALUE, struct tmx *))
{
    char buffer[SMALLBUF], *buf = buffer;
    struct tmx tmx;
    long len;
    VALUE str;

    (*func)(self, &tmx);
    len = date_strftime_alloc(&buf, fmt, &tmx);
    RB_GC_GUARD(self);
    str = rb_usascii_str_new(buf, len);
    if (buf != buffer) xfree(buf);
    return str;
}


ins_to_day(int n)
{
    return ns_to_day(INT2FIX(n));
}


m_zone(union DateData *x)
{
    if (simple_dat_p(x))
	return rb_usascii_str_new2("+00:00");
    return of2str(m_of(x));
}


date_s_test_unit_conv(VALUE klass)
{
    if (!test_unit_v2v_iter(sec_to_day, day_to_sec))
	return Qfalse;
    if (!test_unit_v2v_iter(ms_to_sec, sec_to_ms))
	return Qfalse;
    if (!test_unit_v2v_iter(ns_to_day, day_to_ns))
	return Qfalse;
    if (!test_unit_v2v_iter(ns_to_sec, sec_to_ns))
	return Qfalse;
    return Qtrue;
}


dt_lite_strftime(int argc, VALUE *argv, VALUE self)
{
    return date_strftime_internal(argc, argv, self,
				  "%Y-%m-%dT%H:%M:%S%:z", set_tmx);
}


m_mday(union DateData *x)
{
    if (simple_dat_p(x)) {
	get_s_civil(x);
#ifndef USE_PACK
	return x->s.mday;
#else
	return EX_MDAY(x->s.pc);
#endif
    }
    else {
	get_c_civil(x);
#ifndef USE_PACK
	return x->c.mday;
#else
	return EX_MDAY(x->c.pc);
#endif
    }
}


rt__valid_jd_p(VALUE jd, VALUE sg)
{
    return jd;
}


m_local_df_in_day(union DateData *x)
{
    return isec_to_day(m_local_df(x));
}


d_lite_new_offset(int argc, VALUE *argv, VALUE self)
{
    VALUE vof;
    int rof;

    rb_scan_args(argc, argv, "01", &vof);

    rof = 0;
    if (argc >= 1)
	val2off(vof, rof);

    return dup_obj_with_new_offset(self, rof);
}


rt__valid_ordinal_p(VALUE y, VALUE d, VALUE sg)
{
    VALUE nth, rjd2;
    int ry, rd, rjd, ns;

    if (!valid_ordinal_p(y, NUM2INT(d), NUM2DBL(sg),
			 &nth, &ry,
			 &rd, &rjd,
			 &ns))
	return Qnil;
    encode_jd(nth, rjd, &rjd2);
    return rjd2;
}


date_s_iso8601(int argc, VALUE *argv, VALUE klass)
{
    VALUE str, sg, opt;

    rb_scan_args(argc, argv, "02:", &str, &sg, &opt);
    if (!NIL_P(opt)) argc--;

    switch (argc) {
      case 0:
	str = rb_str_new2("-4712-01-01");
      case 1:
	sg = INT2FIX(DEFAULT_SG);
    }

    {
        int argc2 = 1;
        VALUE argv2[2];
        argv2[0] = str;
        if (!NIL_P(opt)) argv2[argc2++] = opt;
	VALUE hash = date_s__iso8601(argc2, argv2, klass);
	return d_new_by_frags(klass, hash, sg);
    }
}


d_complex_new_internal(VALUE klass,
		       VALUE nth, int jd,
		       int df, VALUE sf,
		       int of, double sg,
		       int y, int m, int d,
		       int h, int min, int s,
		       unsigned flags)
{
    struct ComplexDateData *dat;
    VALUE obj;

    obj = TypedData_Make_Struct(klass, struct ComplexDateData,
				&d_lite_type, dat);
    set_to_complex(obj, dat, nth, jd, df, sf, of, sg,
		   y, m, d, h, min, s, flags);

    assert(have_jd_p(dat) || have_civil_p(dat));
    assert(have_df_p(dat) || have_time_p(dat));

    return obj;
}


c_virtual_sg(union DateData *x)
{
    if (isinf(x->c.sg))
	return x->c.sg;
    if (f_zero_p(x->c.nth))
	return x->c.sg;
    else if (f_negative_p(x->c.nth))
	return positive_inf;
    return negative_inf;
}


date_to_datetime(VALUE self)
{
    get_d1a(self);

    if (simple_dat_p(adat)) {
	VALUE new = d_lite_s_alloc_simple(cDateTime);
	{
	    get_d1b(new);
	    bdat->s = adat->s;
	    return new;
	}
    }
    else {
	VALUE new = d_lite_s_alloc_complex(cDateTime);
	{
	    get_d1b(new);
	    bdat->c = adat->c;
	    bdat->c.df = 0;
	    RB_OBJ_WRITE(new, &bdat->c.sf, INT2FIX(0));
#ifndef USE_PACK
	    bdat->c.hour = 0;
	    bdat->c.min = 0;
	    bdat->c.sec = 0;
#else
	    bdat->c.pc = PACK5(EX_MON(adat->c.pc), EX_MDAY(adat->c.pc),
			       0, 0, 0);
	    bdat->c.flags |= HAVE_DF | HAVE_TIME;
#endif
	    return new;
	}
    }
}


m_wnumx(union DateData *x, int f)
{
    int ry, rw, rd;

    c_jd_to_weeknum(m_local_jd(x), f, m_virtual_sg(x), /* !=m_sg() */
		    &ry, &rw, &rd);
    return rw;
}


d_lite_yday(VALUE self)
{
    get_d1(self);
    return INT2FIX(m_yday(dat));
}


m_wday(union DateData *x)
{
    return c_jd_to_wday(m_local_jd(x));
}


d_lite_wnum0(VALUE self)
{
    get_d1(self);
    return INT2FIX(m_wnum0(dat));
}


d_lite_prev_month(int argc, VALUE *argv, VALUE self)
{
    VALUE n;

    rb_scan_args(argc, argv, "01", &n);
    if (argc < 1)
	n = INT2FIX(1);
    return d_lite_lshift(self, n);
}


c_gregorian_last_day_of_month(int y, int m)
{
    assert(m >= 1 && m <= 12);
    return monthtab[c_gregorian_leap_p(y) ? 1 : 0][m];
}


get_s_civil(union DateData *x)
{
    assert(simple_dat_p(x));
    if (!have_civil_p(x)) {
	int y, m, d;

	assert(have_jd_p(x));
	c_jd_to_civil(x->s.jd, s_virtual_sg(x), &y, &m, &d);
	x->s.year = y;
#ifndef USE_PACK
	x->s.mon = m;
	x->s.mday = d;
#else
	x->s.pc = PACK2(m, d);
#endif
	x->s.flags |= HAVE_CIVIL;
    }
}


div_day(VALUE d, VALUE *f)
{
    if (f)
	*f = f_mod(d, INT2FIX(1));
    return f_floor(d);
}


d_lite_initialize(int argc, VALUE *argv, VALUE self)
{
    VALUE jd, vjd, vdf, sf, vsf, vof, vsg;
    int df, of;
    double sg;

    rb_check_frozen(self);

    rb_scan_args(argc, argv, "05", &vjd, &vdf, &vsf, &vof, &vsg);

    jd = INT2FIX(0);
    df = 0;
    sf = INT2FIX(0);
    of = 0;
    sg = DEFAULT_SG;

    switch (argc) {
      case 5:
	val2sg(vsg, sg);
      case 4:
	val2off(vof, of);
      case 3:
	sf = vsf;
	if (f_lt_p(sf, INT2FIX(0)) ||
	    f_ge_p(sf, INT2FIX(SECOND_IN_NANOSECONDS)))
	    rb_raise(eDateError, "invalid second fraction");
      case 2:
	df = NUM2INT(vdf);
	if (df < 0 || df >= DAY_IN_SECONDS)
	    rb_raise(eDateError, "invalid day fraction");
      case 1:
	jd = vjd;
    }

    {
	VALUE nth;
	int rjd;

	get_d1(self);

	decode_jd(jd, &nth, &rjd);
	if (!df && f_zero_p(sf) && !of) {
	    set_to_simple(self, &dat->s, nth, rjd, sg, 0, 0, 0, HAVE_JD);
	}
	else {
	    if (!complex_dat_p(dat))
		rb_raise(rb_eArgError,
			 "cannot load complex into simple");

	    set_to_complex(self, &dat->c, nth, rjd, df, sf, of, sg,
			   0, 0, 0, 0, 0, 0, HAVE_JD | HAVE_DF);
	}
    }
    return self;
}


d_lite_jisx0301(VALUE self)
{
    char fmtbuf[JISX0301_DATE_SIZE];
    const char *fmt;

    get_d1(self);
    fmt = jisx0301_date_format(fmtbuf, sizeof(fmtbuf),
			       m_real_local_jd(dat),
			       m_real_year(dat));
    return strftimev(fmt, self, set_tmx);
}


valid_civil_sub(int argc, VALUE *argv, VALUE klass, int need_jd)
{
    VALUE nth, y;
    int m, d, ry, rm, rd;
    double sg;

    y = argv[0];
    m = NUM2INT(argv[1]);
    d = NUM2INT(argv[2]);
    sg = NUM2DBL(argv[3]);

    valid_sg(sg);

    if (!need_jd && (guess_style(y, sg) < 0)) {
	if (!valid_gregorian_p(y, m, d,
			       &nth, &ry,
			       &rm, &rd))
	    return Qnil;
	return INT2FIX(0); /* dummy */
    }
    else {
	int rjd, ns;
	VALUE rjd2;

	if (!valid_civil_p(y, m, d, sg,
			   &nth, &ry,
			   &rm, &rd, &rjd,
			   &ns))
	    return Qnil;
	if (!need_jd)
	    return INT2FIX(0); /* dummy */
	encode_jd(nth, rjd, &rjd2);
	return rjd2;
    }
}


c_valid_nth_kday_p(int y, int m, int n, int k, double sg,
		   int *rm, int *rn, int *rk, int *rjd, int *ns)
{
    int ns2, ry2, rm2, rn2, rk2;

    if (k < 0)
	k += 7;
    if (n < 0) {
	int t, ny, nm, rjd2;

	t = y * 12 + m;
	ny = DIV(t, 12);
	nm = MOD(t, 12) + 1;

	c_nth_kday_to_jd(ny, nm, 1, k, sg, &rjd2, &ns2);
	c_jd_to_nth_kday(rjd2 + n * 7, sg, &ry2, &rm2, &rn2, &rk2);
	if (ry2 != y || rm2 != m)
	    return 0;
	n = rn2;
    }
    c_nth_kday_to_jd(y, m, n, k, sg, rjd, ns);
    c_jd_to_nth_kday(*rjd, sg, &ry2, rm, rn, rk);
    if (y != ry2 || m != *rm || n != *rn || k != *rk)
	return 0;
    return 1;
}


c_valid_start_p(double sg)
{
    if (isnan(sg))
	return 0;
    if (isinf(sg))
	return 1;
    if (sg < REFORM_BEGIN_JD || sg > REFORM_END_JD)
	return 0;
    return 1;
}


c_find_ldoy(int y, double sg, int *rjd, int *ns)
{
    int i, rm, rd;

    for (i = 0; i < 30; i++)
	if (c_valid_civil_p(y, 12, 31 - i, sg, &rm, &rd, rjd, ns))
	    return 1;
    return 0;
}


d_lite_upto(VALUE self, VALUE max)
{
    VALUE date;

    RETURN_ENUMERATOR(self, 1, &max);

    date = self;
    while (FIX2INT(d_lite_cmp(date, max)) <= 0) {
	rb_yield(date);
	date = d_lite_plus(date, INT2FIX(1));
    }
    return self;
}


to_integer(VALUE x)
{
    if (RB_INTEGER_TYPE_P(x))
	return x;
    return f_to_i(x);
}


min_trunc(VALUE min, VALUE *fr)
{
    VALUE rmin;

    if (wholenum_p(min)) {
	rmin = to_integer(min);
	*fr = INT2FIX(0);
    }
    else {
	rmin = f_idiv(min, INT2FIX(1));
	*fr = f_mod(min, INT2FIX(1));
	*fr = f_quo(*fr, INT2FIX(1440));
    }
    return rmin;
}


d_lite_hash(VALUE self)
{
    st_index_t v, h[4];

    get_d1(self);
    h[0] = m_nth(dat);
    h[1] = m_jd(dat);
    h[2] = m_df(dat);
    h[3] = m_sf(dat);
    v = rb_memhash(h, sizeof(h));
    return ST2FIX(v);
}


m_df_in_day(union DateData *x)
{
    return isec_to_day(m_df(x));
}


Init_date_core(void)
{
    #ifdef HAVE_RB_EXT_RACTOR_SAFE
	RB_EXT_RACTOR_SAFE(true);
    #endif
    id_cmp = rb_intern_const("<=>");
    id_le_p = rb_intern_const("<=");
    id_ge_p = rb_intern_const(">=");
    id_eqeq_p = rb_intern_const("==");

    half_days_in_day = rb_rational_new2(INT2FIX(1), INT2FIX(2));

#if (LONG_MAX / DAY_IN_SECONDS) > SECOND_IN_NANOSECONDS
    day_in_nanoseconds = LONG2NUM((long)DAY_IN_SECONDS *
				  SECOND_IN_NANOSECONDS);
#elif defined HAVE_LONG_LONG
    day_in_nanoseconds = LL2NUM((LONG_LONG)DAY_IN_SECONDS *
				SECOND_IN_NANOSECONDS);
#else
    day_in_nanoseconds = f_mul(INT2FIX(DAY_IN_SECONDS),
			       INT2FIX(SECOND_IN_NANOSECONDS));
#endif

    rb_gc_register_mark_object(half_days_in_day);
    rb_gc_register_mark_object(day_in_nanoseconds);

    positive_inf = +INFINITY;
    negative_inf = -INFINITY;

    /*
     * date and datetime class - Tadayoshi Funaba 1998-2011
     *
     * 'date' provides two classes: Date and DateTime.
     *
     * == Terms and Definitions
     *
     * Some terms and definitions are based on ISO 8601 and JIS X 0301.
     *
     * === Calendar Date
     *
     * The calendar date is a particular day of a calendar year,
     * identified by its ordinal number within a calendar month within
     * that year.
     *
     * In those classes, this is so-called "civil".
     *
     * === Ordinal Date
     *
     * The ordinal date is a particular day of a calendar year identified
     * by its ordinal number within the year.
     *
     * In those classes, this is so-called "ordinal".
     *
     * === Week Date
     *
     * The week date is a date identified by calendar week and day numbers.
     *
     * The calendar week is a seven day period within a calendar year,
     * starting on a Monday and identified by its ordinal number within
     * the year; the first calendar week of the year is the one that
     * includes the first Thursday of that year. In the Gregorian
     * calendar, this is equivalent to the week which includes January 4.
     *
     * In those classes, this is so-called "commercial".
     *
     * === Julian Day Number
     *
     * The Julian day number is in elapsed days since noon (Greenwich Mean
     * Time) on January 1, 4713 BCE (in the Julian calendar).
     *
     * In this document, the astronomical Julian day number is the same as
     * the original Julian day number. And the chronological Julian day
     * number is a variation of the Julian day number. Its days begin at
     * midnight on local time.
     *
     * In this document, when the term "Julian day number" simply appears,
     * it just refers to "chronological Julian day number", not the
     * original.
     *
     * In those classes, those are so-called "ajd" and "jd".
     *
     * === Modified Julian Day Number
     *
     * The modified Julian day number is in elapsed days since midnight
     * (Coordinated Universal Time) on November 17, 1858 CE (in the
     * Gregorian calendar).
     *
     * In this document, the astronomical modified Julian day number is
     * the same as the original modified Julian day number. And the
     * chronological modified Julian day number is a variation of the
     * modified Julian day number. Its days begin at midnight on local
     * time.
     *
     * In this document, when the term "modified Julian day number" simply
     * appears, it just refers to "chronological modified Julian day
     * number", not the original.
     *
     * In those classes, those are so-called "amjd" and "mjd".
     *
     * == Date
     *
     * A subclass of Object that includes the Comparable module and
     * easily handles date.
     *
     * A Date object is created with Date::new, Date::jd, Date::ordinal,
     * Date::commercial, Date::parse, Date::strptime, Date::today,
     * Time#to_date, etc.
     *
     *     require 'date'
     *
     *     Date.new(2001,2,3)
     *	    #=> #<Date: 2001-02-03 ...>
     *     Date.jd(2451944)
     *	    #=> #<Date: 2001-02-03 ...>
     *     Date.ordinal(2001,34)
     *	    #=> #<Date: 2001-02-03 ...>
     *     Date.commercial(2001,5,6)
     *	    #=> #<Date: 2001-02-03 ...>
     *     Date.parse('2001-02-03')
     *	    #=> #<Date: 2001-02-03 ...>
     *     Date.strptime('03-02-2001', '%d-%m-%Y')
     *	    #=> #<Date: 2001-02-03 ...>
     *     Time.new(2001,2,3).to_date
     *	    #=> #<Date: 2001-02-03 ...>
     *
     * All date objects are immutable; hence cannot modify themselves.
     *
     * The concept of a date object can be represented as a tuple
     * of the day count, the offset and the day of calendar reform.
     *
     * The day count denotes the absolute position of a temporal
     * dimension. The offset is relative adjustment, which determines
     * decoded local time with the day count. The day of calendar
     * reform denotes the start day of the new style. The old style
     * of the West is the Julian calendar which was adopted by
     * Caesar. The new style is the Gregorian calendar, which is the
     * current civil calendar of many countries.
     *
     * The day count is virtually the astronomical Julian day number.
     * The offset in this class is usually zero, and cannot be
     * specified directly.
     *
     * A Date object can be created with an optional argument,
     * the day of calendar reform as a Julian day number, which
     * should be 2298874 to 2426355 or negative/positive infinity.
     * The default value is +Date::ITALY+ (2299161=1582-10-15).
     * See also sample/cal.rb.
     *
     *     $ ruby sample/cal.rb -c it 10 1582
     *         October 1582
     *      S  M Tu  W Th  F  S
     *         1  2  3  4 15 16
     *     17 18 19 20 21 22 23
     *     24 25 26 27 28 29 30
     *     31
     *
     *     $ ruby sample/cal.rb -c gb  9 1752
     *        September 1752
     *      S  M Tu  W Th  F  S
     *            1  2 14 15 16
     *     17 18 19 20 21 22 23
     *     24 25 26 27 28 29 30
     *
     * A Date object has various methods. See each reference.
     *
     *     d = Date.parse('3rd Feb 2001')
     *					#=> #<Date: 2001-02-03 ...>
     *     d.year			#=> 2001
     *     d.mon			#=> 2
     *     d.mday			#=> 3
     *     d.wday			#=> 6
     *     d += 1			#=> #<Date: 2001-02-04 ...>
     *     d.strftime('%a %d %b %Y')	#=> "Sun 04 Feb 2001"
     *
     */
    cDate = rb_define_class("Date", rb_cObject);
    eDateError = rb_define_class_under(cDate, "Error", rb_eArgError);

    rb_include_module(cDate, rb_mComparable);

    /* An array of strings of full month names in English.  The first
     * element is nil.
     */
    rb_define_const(cDate, "MONTHNAMES", mk_ary_of_str(13, monthnames));

    /* An array of strings of abbreviated month names in English.  The
     * first element is nil.
     */
    rb_define_const(cDate, "ABBR_MONTHNAMES",
		    mk_ary_of_str(13, abbr_monthnames));

    /* An array of strings of the full names of days of the week in English.
     * The first is "Sunday".
     */
    rb_define_const(cDate, "DAYNAMES", mk_ary_of_str(7, daynames));

    /* An array of strings of abbreviated day names in English.  The
     * first is "Sun".
     */
    rb_define_const(cDate, "ABBR_DAYNAMES", mk_ary_of_str(7, abbr_daynames));

    /* The Julian day number of the day of calendar reform for Italy
     * and some catholic countries.
     */
    rb_define_const(cDate, "ITALY", INT2FIX(ITALY));

    /* The Julian day number of the day of calendar reform for England
     * and her colonies.
     */
    rb_define_const(cDate, "ENGLAND", INT2FIX(ENGLAND));

    /* The Julian day number of the day of calendar reform for the
     * proleptic Julian calendar.
     */
    rb_define_const(cDate, "JULIAN", DBL2NUM(JULIAN));

    /* The Julian day number of the day of calendar reform for the
     * proleptic Gregorian calendar.
     */
    rb_define_const(cDate, "GREGORIAN", DBL2NUM(GREGORIAN));

    rb_define_alloc_func(cDate, d_lite_s_alloc_simple);

#ifndef NDEBUG
    rb_define_private_method(CLASS_OF(cDate), "_valid_jd?",
			     date_s__valid_jd_p, -1);
    rb_define_private_method(CLASS_OF(cDate), "_valid_ordinal?",
			     date_s__valid_ordinal_p, -1);
    rb_define_private_method(CLASS_OF(cDate), "_valid_civil?",
			     date_s__valid_civil_p, -1);
    rb_define_private_method(CLASS_OF(cDate), "_valid_date?",
			     date_s__valid_civil_p, -1);
    rb_define_private_method(CLASS_OF(cDate), "_valid_commercial?",
			     date_s__valid_commercial_p, -1);
    rb_define_private_method(CLASS_OF(cDate), "_valid_weeknum?",
			     date_s__valid_weeknum_p, -1);
    rb_define_private_method(CLASS_OF(cDate), "_valid_nth_kday?",
			     date_s__valid_nth_kday_p, -1);
#endif

    rb_define_singleton_method(cDate, "valid_jd?", date_s_valid_jd_p, -1);
    rb_define_singleton_method(cDate, "valid_ordinal?",
			       date_s_valid_ordinal_p, -1);
    rb_define_singleton_method(cDate, "valid_civil?", date_s_valid_civil_p, -1);
    rb_define_singleton_method(cDate, "valid_date?", date_s_valid_civil_p, -1);
    rb_define_singleton_method(cDate, "valid_commercial?",
			       date_s_valid_commercial_p, -1);

#ifndef NDEBUG
    rb_define_private_method(CLASS_OF(cDate), "valid_weeknum?",
			     date_s_valid_weeknum_p, -1);
    rb_define_private_method(CLASS_OF(cDate), "valid_nth_kday?",
			     date_s_valid_nth_kday_p, -1);
    rb_define_private_method(CLASS_OF(cDate), "zone_to_diff",
			     date_s_zone_to_diff, 1);
#endif

    rb_define_singleton_method(cDate, "julian_leap?", date_s_julian_leap_p, 1);
    rb_define_singleton_method(cDate, "gregorian_leap?",
			       date_s_gregorian_leap_p, 1);
    rb_define_singleton_method(cDate, "leap?",
			       date_s_gregorian_leap_p, 1);

#ifndef NDEBUG
    rb_define_singleton_method(cDate, "new!", date_s_new_bang, -1);
    rb_define_alias(rb_singleton_class(cDate), "new_l!", "new");
#endif

    rb_define_singleton_method(cDate, "jd", date_s_jd, -1);
    rb_define_singleton_method(cDate, "ordinal", date_s_ordinal, -1);
    rb_define_singleton_method(cDate, "civil", date_s_civil, -1);
    rb_define_singleton_method(cDate, "commercial", date_s_commercial, -1);

#ifndef NDEBUG
    rb_define_singleton_method(cDate, "weeknum", date_s_weeknum, -1);
    rb_define_singleton_method(cDate, "nth_kday", date_s_nth_kday, -1);
#endif

    rb_define_singleton_method(cDate, "today", date_s_today, -1);
    rb_define_singleton_method(cDate, "_strptime", date_s__strptime, -1);
    rb_define_singleton_method(cDate, "strptime", date_s_strptime, -1);
    rb_define_singleton_method(cDate, "_parse", date_s__parse, -1);
    rb_define_singleton_method(cDate, "parse", date_s_parse, -1);
    rb_define_singleton_method(cDate, "_iso8601", date_s__iso8601, -1);
    rb_define_singleton_method(cDate, "iso8601", date_s_iso8601, -1);
    rb_define_singleton_method(cDate, "_rfc3339", date_s__rfc3339, -1);
    rb_define_singleton_method(cDate, "rfc3339", date_s_rfc3339, -1);
    rb_define_singleton_method(cDate, "_xmlschema", date_s__xmlschema, -1);
    rb_define_singleton_method(cDate, "xmlschema", date_s_xmlschema, -1);
    rb_define_singleton_method(cDate, "_rfc2822", date_s__rfc2822, -1);
    rb_define_singleton_method(cDate, "_rfc822", date_s__rfc2822, -1);
    rb_define_singleton_method(cDate, "rfc2822", date_s_rfc2822, -1);
    rb_define_singleton_method(cDate, "rfc822", date_s_rfc2822, -1);
    rb_define_singleton_method(cDate, "_httpdate", date_s__httpdate, -1);
    rb_define_singleton_method(cDate, "httpdate", date_s_httpdate, -1);
    rb_define_singleton_method(cDate, "_jisx0301", date_s__jisx0301, -1);
    rb_define_singleton_method(cDate, "jisx0301", date_s_jisx0301, -1);

    rb_define_method(cDate, "initialize", date_initialize, -1);
    rb_define_method(cDate, "initialize_copy", d_lite_initialize_copy, 1);

#ifndef NDEBUG
    rb_define_method(cDate, "fill", d_lite_fill, 0);
#endif

    rb_define_method(cDate, "ajd", d_lite_ajd, 0);
    rb_define_method(cDate, "amjd", d_lite_amjd, 0);
    rb_define_method(cDate, "jd", d_lite_jd, 0);
    rb_define_method(cDate, "mjd", d_lite_mjd, 0);
    rb_define_method(cDate, "ld", d_lite_ld, 0);

    rb_define_method(cDate, "year", d_lite_year, 0);
    rb_define_method(cDate, "yday", d_lite_yday, 0);
    rb_define_method(cDate, "mon", d_lite_mon, 0);
    rb_define_method(cDate, "month", d_lite_mon, 0);
    rb_define_method(cDate, "mday", d_lite_mday, 0);
    rb_define_method(cDate, "day", d_lite_mday, 0);
    rb_define_method(cDate, "day_fraction", d_lite_day_fraction, 0);

    rb_define_method(cDate, "cwyear", d_lite_cwyear, 0);
    rb_define_method(cDate, "cweek", d_lite_cweek, 0);
    rb_define_method(cDate, "cwday", d_lite_cwday, 0);

#ifndef NDEBUG
    rb_define_private_method(cDate, "wnum0", d_lite_wnum0, 0);
    rb_define_private_method(cDate, "wnum1", d_lite_wnum1, 0);
#endif

    rb_define_method(cDate, "wday", d_lite_wday, 0);

    rb_define_method(cDate, "sunday?", d_lite_sunday_p, 0);
    rb_define_method(cDate, "monday?", d_lite_monday_p, 0);
    rb_define_method(cDate, "tuesday?", d_lite_tuesday_p, 0);
    rb_define_method(cDate, "wednesday?", d_lite_wednesday_p, 0);
    rb_define_method(cDate, "thursday?", d_lite_thursday_p, 0);
    rb_define_method(cDate, "friday?", d_lite_friday_p, 0);
    rb_define_method(cDate, "saturday?", d_lite_saturday_p, 0);

#ifndef NDEBUG
    rb_define_method(cDate, "nth_kday?", d_lite_nth_kday_p, 2);
#endif

    rb_define_private_method(cDate, "hour", d_lite_zero, 0);
    rb_define_private_method(cDate, "min", d_lite_zero, 0);
    rb_define_private_method(cDate, "minute", d_lite_zero, 0);
    rb_define_private_method(cDate, "sec", d_lite_zero, 0);
    rb_define_private_method(cDate, "second", d_lite_zero, 0);

    rb_define_method(cDate, "julian?", d_lite_julian_p, 0);
    rb_define_method(cDate, "gregorian?", d_lite_gregorian_p, 0);
    rb_define_method(cDate, "leap?", d_lite_leap_p, 0);

    rb_define_method(cDate, "start", d_lite_start, 0);
    rb_define_method(cDate, "new_start", d_lite_new_start, -1);
    rb_define_method(cDate, "italy", d_lite_italy, 0);
    rb_define_method(cDate, "england", d_lite_england, 0);
    rb_define_method(cDate, "julian", d_lite_julian, 0);
    rb_define_method(cDate, "gregorian", d_lite_gregorian, 0);

    rb_define_method(cDate, "+", d_lite_plus, 1);
    rb_define_method(cDate, "-", d_lite_minus, 1);

    rb_define_method(cDate, "next_day", d_lite_next_day, -1);
    rb_define_method(cDate, "prev_day", d_lite_prev_day, -1);
    rb_define_method(cDate, "next", d_lite_next, 0);
    rb_define_method(cDate, "succ", d_lite_next, 0);

    rb_define_method(cDate, ">>", d_lite_rshift, 1);
    rb_define_method(cDate, "<<", d_lite_lshift, 1);

    rb_define_method(cDate, "next_month", d_lite_next_month, -1);
    rb_define_method(cDate, "prev_month", d_lite_prev_month, -1);
    rb_define_method(cDate, "next_year", d_lite_next_year, -1);
    rb_define_method(cDate, "prev_year", d_lite_prev_year, -1);

    rb_define_method(cDate, "step", d_lite_step, -1);
    rb_define_method(cDate, "upto", d_lite_upto, 1);
    rb_define_method(cDate, "downto", d_lite_downto, 1);

    rb_define_method(cDate, "<=>", d_lite_cmp, 1);
    rb_define_method(cDate, "===", d_lite_equal, 1);
    rb_define_method(cDate, "eql?", d_lite_eql_p, 1);
    rb_define_method(cDate, "hash", d_lite_hash, 0);

    rb_define_method(cDate, "to_s", d_lite_to_s, 0);
#ifndef NDEBUG
    rb_define_method(cDate, "inspect_raw", d_lite_inspect_raw, 0);
#endif
    rb_define_method(cDate, "inspect", d_lite_inspect, 0);

    rb_define_method(cDate, "strftime", d_lite_strftime, -1);

    rb_define_method(cDate, "asctime", d_lite_asctime, 0);
    rb_define_method(cDate, "ctime", d_lite_asctime, 0);
    rb_define_method(cDate, "iso8601", d_lite_iso8601, 0);
    rb_define_method(cDate, "xmlschema", d_lite_iso8601, 0);
    rb_define_method(cDate, "rfc3339", d_lite_rfc3339, 0);
    rb_define_method(cDate, "rfc2822", d_lite_rfc2822, 0);
    rb_define_method(cDate, "rfc822", d_lite_rfc2822, 0);
    rb_define_method(cDate, "httpdate", d_lite_httpdate, 0);
    rb_define_method(cDate, "jisx0301", d_lite_jisx0301, 0);

#ifndef NDEBUG
    rb_define_method(cDate, "marshal_dump_old", d_lite_marshal_dump_old, 0);
#endif
    rb_define_method(cDate, "marshal_dump", d_lite_marshal_dump, 0);
    rb_define_method(cDate, "marshal_load", d_lite_marshal_load, 1);
    rb_define_singleton_method(cDate, "_load", date_s__load, 1);

    /*
     * == DateTime
     *
     * A subclass of Date that easily handles date, hour, minute, second,
     * and offset.
     *
     * DateTime class is considered deprecated. Use Time class.
     *
     * DateTime does not consider any leap seconds, does not track
     * any summer time rules.
     *
     * A DateTime object is created with DateTime::new, DateTime::jd,
     * DateTime::ordinal, DateTime::commercial, DateTime::parse,
     * DateTime::strptime, DateTime::now, Time#to_datetime, etc.
     *
     *     require 'date'
     *
     *     DateTime.new(2001,2,3,4,5,6)
     *                         #=> #<DateTime: 2001-02-03T04:05:06+00:00 ...>
     *
     * The last element of day, hour, minute, or second can be a
     * fractional number. The fractional number's precision is assumed
     * at most nanosecond.
     *
     *     DateTime.new(2001,2,3.5)
     *                         #=> #<DateTime: 2001-02-03T12:00:00+00:00 ...>
     *
     * An optional argument, the offset, indicates the difference
     * between the local time and UTC. For example, <tt>Rational(3,24)</tt>
     * represents ahead of 3 hours of UTC, <tt>Rational(-5,24)</tt> represents
     * behind of 5 hours of UTC. The offset should be -1 to +1, and
     * its precision is assumed at most second. The default value is
     * zero (equals to UTC).
     *
     *     DateTime.new(2001,2,3,4,5,6,Rational(3,24))
     *                         #=> #<DateTime: 2001-02-03T04:05:06+03:00 ...>
     *
     * The offset also accepts string form:
     *
     *     DateTime.new(2001,2,3,4,5,6,'+03:00')
     *                         #=> #<DateTime: 2001-02-03T04:05:06+03:00 ...>
     *
     * An optional argument, the day of calendar reform (+start+), denotes
     * a Julian day number, which should be 2298874 to 2426355 or
     * negative/positive infinity.
     * The default value is +Date::ITALY+ (2299161=1582-10-15).
     *
     * A DateTime object has various methods. See each reference.
     *
     *     d = DateTime.parse('3rd Feb 2001 04:05:06+03:30')
     *                         #=> #<DateTime: 2001-02-03T04:05:06+03:30 ...>
     *     d.hour              #=> 4
     *     d.min               #=> 5
     *     d.sec               #=> 6
     *     d.offset            #=> (7/48)
     *     d.zone              #=> "+03:30"
     *     d += Rational('1.5')
     *                         #=> #<DateTime: 2001-02-04%16:05:06+03:30 ...>
     *     d = d.new_offset('+09:00')
     *                         #=> #<DateTime: 2001-02-04%21:35:06+09:00 ...>
     *     d.strftime('%I:%M:%S %p')
     *                         #=> "09:35:06 PM"
     *     d > DateTime.new(1999)
     *                         #=> true
     *
     * === When should you use DateTime and when should you use Time?
     *
     * It's a common misconception that
     * {William Shakespeare}[https://en.wikipedia.org/wiki/William_Shakespeare]
     * and
     * {Miguel de Cervantes}[https://en.wikipedia.org/wiki/Miguel_de_Cervantes]
     * died on the same day in history -
     * so much so that UNESCO named April 23 as
     * {World Book Day because of this fact}[https://en.wikipedia.org/wiki/World_Book_Day].
     * However, because England hadn't yet adopted the
     * {Gregorian Calendar Reform}[https://en.wikipedia.org/wiki/Gregorian_calendar#Gregorian_reform]
     * (and wouldn't until {1752}[https://en.wikipedia.org/wiki/Calendar_(New_Style)_Act_1750])
     * their deaths are actually 10 days apart.
     * Since Ruby's Time class implements a
     * {proleptic Gregorian calendar}[https://en.wikipedia.org/wiki/Proleptic_Gregorian_calendar]
     * and has no concept of calendar reform there's no way
     * to express this with Time objects. This is where DateTime steps in:
     *
     *     shakespeare = DateTime.iso8601('1616-04-23', Date::ENGLAND)
     *      #=> Tue, 23 Apr 1616 00:00:00 +0000
     *     cervantes = DateTime.iso8601('1616-04-23', Date::ITALY)
     *      #=> Sat, 23 Apr 1616 00:00:00 +0000
     *
     * Already you can see something is weird - the days of the week
     * are different. Taking this further:
     *
     *     cervantes == shakespeare
     *      #=> false
     *     (shakespeare - cervantes).to_i
     *      #=> 10
     *
     * This shows that in fact they died 10 days apart (in reality
     * 11 days since Cervantes died a day earlier but was buried on
     * the 23rd). We can see the actual date of Shakespeare's death by
     * using the #gregorian method to convert it:
     *
     *     shakespeare.gregorian
     *      #=> Tue, 03 May 1616 00:00:00 +0000
     *
     * So there's an argument that all the celebrations that take
     * place on the 23rd April in Stratford-upon-Avon are actually
     * the wrong date since England is now using the Gregorian calendar.
     * You can see why when we transition across the reform
     * date boundary:
     *
     *     # start off with the anniversary of Shakespeare's birth in 1751
     *     shakespeare = DateTime.iso8601('1751-04-23', Date::ENGLAND)
     *      #=> Tue, 23 Apr 1751 00:00:00 +0000
     *
     *     # add 366 days since 1752 is a leap year and April 23 is after February 29
     *     shakespeare + 366
     *      #=> Thu, 23 Apr 1752 00:00:00 +0000
     *
     *     # add another 365 days to take us to the anniversary in 1753
     *     shakespeare + 366 + 365
     *      #=> Fri, 04 May 1753 00:00:00 +0000
     *
     * As you can see, if we're accurately tracking the number of
     * {solar years}[https://en.wikipedia.org/wiki/Tropical_year]
     * since Shakespeare's birthday then the correct anniversary date
     * would be the 4th May and not the 23rd April.
     *
     * So when should you use DateTime in Ruby and when should
     * you use Time? Almost certainly you'll want to use Time
     * since your app is probably dealing with current dates and
     * times. However, if you need to deal with dates and times in a
     * historical context you'll want to use DateTime to avoid
     * making the same mistakes as UNESCO. If you also have to deal
     * with timezones then best of luck - just bear in mind that
     * you'll probably be dealing with
     * {local solar times}[https://en.wikipedia.org/wiki/Solar_time],
     * since it wasn't until the 19th century that the introduction
     * of the railways necessitated the need for
     * {Standard Time}[https://en.wikipedia.org/wiki/Standard_time#Great_Britain]
     * and eventually timezones.
     */

    cDateTime = rb_define_class("DateTime", cDate);
    rb_define_alloc_func(cDateTime, d_lite_s_alloc_complex);

    rb_define_singleton_method(cDateTime, "jd", datetime_s_jd, -1);
    rb_define_singleton_method(cDateTime, "ordinal", datetime_s_ordinal, -1);
    rb_define_singleton_method(cDateTime, "civil", datetime_s_civil, -1);
    rb_define_singleton_method(cDateTime, "new", datetime_s_civil, -1);
    rb_define_singleton_method(cDateTime, "commercial",
			       datetime_s_commercial, -1);

#ifndef NDEBUG
    rb_define_singleton_method(cDateTime, "weeknum",
			       datetime_s_weeknum, -1);
    rb_define_singleton_method(cDateTime, "nth_kday",
			       datetime_s_nth_kday, -1);
#endif

    rb_undef_method(CLASS_OF(cDateTime), "today");

    rb_define_singleton_method(cDateTime, "now", datetime_s_now, -1);
    rb_define_singleton_method(cDateTime, "_strptime",
			       datetime_s__strptime, -1);
    rb_define_singleton_method(cDateTime, "strptime",
			       datetime_s_strptime, -1);
    rb_define_singleton_method(cDateTime, "parse",
			       datetime_s_parse, -1);
    rb_define_singleton_method(cDateTime, "iso8601",
			       datetime_s_iso8601, -1);
    rb_define_singleton_method(cDateTime, "rfc3339",
			       datetime_s_rfc3339, -1);
    rb_define_singleton_method(cDateTime, "xmlschema",
			       datetime_s_xmlschema, -1);
    rb_define_singleton_method(cDateTime, "rfc2822",
			       datetime_s_rfc2822, -1);
    rb_define_singleton_method(cDateTime, "rfc822",
			       datetime_s_rfc2822, -1);
    rb_define_singleton_method(cDateTime, "httpdate",
			       datetime_s_httpdate, -1);
    rb_define_singleton_method(cDateTime, "jisx0301",
			       datetime_s_jisx0301, -1);

    rb_define_method(cDateTime, "hour", d_lite_hour, 0);
    rb_define_method(cDateTime, "min", d_lite_min, 0);
    rb_define_method(cDateTime, "minute", d_lite_min, 0);
    rb_define_method(cDateTime, "sec", d_lite_sec, 0);
    rb_define_method(cDateTime, "second", d_lite_sec, 0);
    rb_define_method(cDateTime, "sec_fraction", d_lite_sec_fraction, 0);
    rb_define_method(cDateTime, "second_fraction", d_lite_sec_fraction, 0);
    rb_define_method(cDateTime, "offset", d_lite_offset, 0);
    rb_define_method(cDateTime, "zone", d_lite_zone, 0);
    rb_define_method(cDateTime, "new_offset", d_lite_new_offset, -1);

    rb_define_method(cDateTime, "to_s", dt_lite_to_s, 0);

    rb_define_method(cDateTime, "strftime", dt_lite_strftime, -1);

    rb_define_method(cDateTime, "iso8601", dt_lite_iso8601, -1);
    rb_define_method(cDateTime, "xmlschema", dt_lite_iso8601, -1);
    rb_define_method(cDateTime, "rfc3339", dt_lite_rfc3339, -1);
    rb_define_method(cDateTime, "jisx0301", dt_lite_jisx0301, -1);

    /* conversions */

    rb_define_method(rb_cTime, "to_time", time_to_time, 0);
    rb_define_method(rb_cTime, "to_date", time_to_date, 0);
    rb_define_method(rb_cTime, "to_datetime", time_to_datetime, 0);

    rb_define_method(cDate, "to_time", date_to_time, 0);
    rb_define_method(cDate, "to_date", date_to_date, 0);
    rb_define_method(cDate, "to_datetime", date_to_datetime, 0);

    rb_define_method(cDateTime, "to_time", datetime_to_time, 0);
    rb_define_method(cDateTime, "to_date", datetime_to_date, 0);
    rb_define_method(cDateTime, "to_datetime", datetime_to_datetime, 0);

#ifndef NDEBUG
    /* tests */

    rb_define_singleton_method(cDate, "test_civil", date_s_test_civil, 0);
    rb_define_singleton_method(cDate, "test_ordinal", date_s_test_ordinal, 0);
    rb_define_singleton_method(cDate, "test_commercial",
			       date_s_test_commercial, 0);
    rb_define_singleton_method(cDate, "test_weeknum", date_s_test_weeknum, 0);
    rb_define_singleton_method(cDate, "test_nth_kday", date_s_test_nth_kday, 0);
    rb_define_singleton_method(cDate, "test_unit_conv",
			       date_s_test_unit_conv, 0);
    rb_define_singleton_method(cDate, "test_all", date_s_test_all, 0);
#endif
}


f_cmp(VALUE x, VALUE y)
{
    if (FIXNUM_P(x) && FIXNUM_P(y)) {
	long c = FIX2LONG(x) - FIX2LONG(y);
	if (c > 0)
	    return 1;
	else if (c < 0)
	    return -1;
	return 0;
    }
    return rb_cmpint(rb_funcallv(x, id_cmp, 1, &y), x, y);
}


c_valid_gregorian_p(int y, int m, int d, int *rm, int *rd)
{
    int last;

    if (m < 0)
	m += 13;
    if (m < 1 || m > 12)
	return 0;
    last = c_gregorian_last_day_of_month(y, m);
    if (d < 0)
	d = last + d + 1;
    if (d < 1 || d > last)
	return 0;
    *rm = m;
    *rd = d;
    return 1;
}


d_lite_inspect_raw(VALUE self)
{
    get_d1(self);
    return mk_inspect_raw(dat, rb_obj_class(self));
}


d_lite_next(VALUE self)
{
    return d_lite_next_day(0, (VALUE *)NULL, self);
}


date_s_valid_commercial_p(int argc, VALUE *argv, VALUE klass)
{
    VALUE vy, vw, vd, vsg;
    VALUE argv2[4];

    rb_scan_args(argc, argv, "31", &vy, &vw, &vd, &vsg);

    RETURN_FALSE_UNLESS_NUMERIC(vy);
    RETURN_FALSE_UNLESS_NUMERIC(vw);
    RETURN_FALSE_UNLESS_NUMERIC(vd);
    argv2[0] = vy;
    argv2[1] = vw;
    argv2[2] = vd;
    if (argc < 4)
	argv2[3] = INT2FIX(DEFAULT_SG);
    else
	argv2[3] = vsg;

    if (NIL_P(valid_commercial_sub(4, argv2, klass, 0)))
	return Qfalse;
    return Qtrue;
}


d_lite_rfc3339(VALUE self)
{
    return strftimev("%Y-%m-%dT%H:%M:%S%:z", self, set_tmx);
}


d_lite_england(VALUE self)
{
    return dup_obj_with_new_start(self, ENGLAND);
}


datetime_s_strptime(int argc, VALUE *argv, VALUE klass)
{
    VALUE str, fmt, sg;

    rb_scan_args(argc, argv, "03", &str, &fmt, &sg);

    switch (argc) {
      case 0:
	str = rb_str_new2("-4712-01-01T00:00:00+00:00");
      case 1:
	fmt = rb_str_new2("%FT%T%z");
      case 2:
	sg = INT2FIX(DEFAULT_SG);
    }

    {
	VALUE argv2[2], hash;

	argv2[0] = str;
	argv2[1] = fmt;
	hash = date_s__strptime(2, argv2, klass);
	return dt_new_by_frags(klass, hash, sg);
    }
}


d_lite_jd(VALUE self)
{
    get_d1(self);
    return m_real_local_jd(dat);
}


datetime_initialize(int argc, VALUE *argv, VALUE self)
{
    VALUE vy, vm, vd, vh, vmin, vs, vof, vsg, y, fr, fr2, ret;
    int m, d, h, min, s, rof;
    double sg;
    struct ComplexDateData *dat = rb_check_typeddata(self, &d_lite_type);

    if (!complex_dat_p(dat)) {
	rb_raise(rb_eTypeError, "DateTime expected");
    }

    rb_scan_args(argc, argv, "08", &vy, &vm, &vd, &vh, &vmin, &vs, &vof, &vsg);

    y = INT2FIX(-4712);
    m = 1;
    d = 1;

    h = min = s = 0;
    fr2 = INT2FIX(0);
    rof = 0;
    sg = DEFAULT_SG;

    switch (argc) {
      case 8:
	val2sg(vsg, sg);
      case 7:
	val2off(vof, rof);
      case 6:
        check_numeric(vs, "second");
	num2int_with_frac(s, positive_inf);
      case 5:
        check_numeric(vmin, "minute");
	num2int_with_frac(min, 5);
      case 4:
        check_numeric(vh, "hour");
	num2int_with_frac(h, 4);
      case 3:
        check_numeric(vd, "day");
	num2int_with_frac(d, 3);
      case 2:
        check_numeric(vm, "month");
	m = NUM2INT(vm);
      case 1:
        check_numeric(vy, "year");
	y = vy;
    }

    if (guess_style(y, sg) < 0) {
	VALUE nth;
	int ry, rm, rd, rh, rmin, rs;

	if (!valid_gregorian_p(y, m, d,
			       &nth, &ry,
			       &rm, &rd))
	    rb_raise(eDateError, "invalid date");
	if (!c_valid_time_p(h, min, s, &rh, &rmin, &rs))
	    rb_raise(eDateError, "invalid date");
	canon24oc();

	set_to_complex(self, dat,
		       nth, 0,
		       0, INT2FIX(0),
		       rof, sg,
		       ry, rm, rd,
		       rh, rmin, rs,
		       HAVE_CIVIL | HAVE_TIME);
    }
    else {
	VALUE nth;
	int ry, rm, rd, rh, rmin, rs, rjd, rjd2, ns;

	if (!valid_civil_p(y, m, d, sg,
			   &nth, &ry,
			   &rm, &rd, &rjd,
			   &ns))
	    rb_raise(eDateError, "invalid date");
	if (!c_valid_time_p(h, min, s, &rh, &rmin, &rs))
	    rb_raise(eDateError, "invalid date");
	canon24oc();

	rjd2 = jd_local_to_utc(rjd,
			       time_to_df(rh, rmin, rs),
			       rof);

	set_to_complex(self, dat,
		       nth, rjd2,
		       0, INT2FIX(0),
		       rof, sg,
		       ry, rm, rd,
		       rh, rmin, rs,
		       HAVE_JD | HAVE_CIVIL | HAVE_TIME);
    }
    ret = self;
    add_frac();
    return ret;
}


m_nth(union DateData *x)
{
    if (simple_dat_p(x))
	return x->s.nth;
    else {
	get_c_civil(x);
	return x->c.nth;
    }
}


d_lite_to_s(VALUE self)
{
    return strftimev("%Y-%m-%d", self, set_tmx);
}


d_lite_cweek(VALUE self)
{
    get_d1(self);
    return INT2FIX(m_cweek(dat));
}


mk_ary_of_str(long len, const char *a[])
{
    VALUE o;
    long i;

    o = rb_ary_new2(len);
    for (i = 0; i < len; i++) {
	VALUE e;

	if (!a[i])
	    e = Qnil;
	else {
	    e = rb_usascii_str_new2(a[i]);
	    rb_obj_freeze(e);
	}
	rb_ary_push(o, e);
    }
    rb_obj_freeze(o);
    return o;
}


date_s__valid_jd_p(int argc, VALUE *argv, VALUE klass)
{
    VALUE vjd, vsg;
    VALUE argv2[2];

    rb_scan_args(argc, argv, "11", &vjd, &vsg);

    argv2[0] = vjd;
    if (argc < 2)
	argv2[1] = DBL2NUM(GREGORIAN);
    else
	argv2[1] = vsg;

    return valid_jd_sub(2, argv2, klass, 1);
}


valid_commercial_p(VALUE y, int w, int d, double sg,
		   VALUE *nth, int *ry,
		   int *rw, int *rd, int *rjd,
		   int *ns)
{
    double style = guess_style(y, sg);
    int r;

    if (style == 0) {
	int jd;

	r = c_valid_commercial_p(FIX2INT(y), w, d, sg, rw, rd, &jd, ns);
	if (!r)
	    return 0;
	decode_jd(INT2FIX(jd), nth, rjd);
	if (f_zero_p(*nth))
	    *ry = FIX2INT(y);
	else {
	    VALUE nth2;
	    decode_year(y, *ns ? -1 : +1, &nth2, ry);
	}
    }
    else {
	decode_year(y, style, nth, ry);
	r = c_valid_commercial_p(*ry, w, d, style, rw, rd, rjd, ns);
    }
    return r;
}


date_s_valid_jd_p(int argc, VALUE *argv, VALUE klass)
{
    VALUE vjd, vsg;
    VALUE argv2[2];

    rb_scan_args(argc, argv, "11", &vjd, &vsg);

    RETURN_FALSE_UNLESS_NUMERIC(vjd);
    argv2[0] = vjd;
    if (argc < 2)
	argv2[1] = INT2FIX(DEFAULT_SG);
    else
	argv2[1] = vsg;

    if (NIL_P(valid_jd_sub(2, argv2, klass, 0)))
	return Qfalse;
    return Qtrue;
}


d_lite_strftime(int argc, VALUE *argv, VALUE self)
{
    return date_strftime_internal(argc, argv, self,
				  "%Y-%m-%d", set_tmx);
}


f_zero_p(VALUE x)
{
    switch (TYPE(x)) {
      case T_FIXNUM:
	return f_boolcast(FIX2LONG(x) == 0);
      case T_BIGNUM:
	return Qfalse;
      case T_RATIONAL:
	{
	    VALUE num = rb_rational_num(x);
	    return f_boolcast(FIXNUM_P(num) && FIX2LONG(num) == 0);
	}
    }
    return rb_funcall(x, id_eqeq_p, 1, INT2FIX(0));
}


date_s__valid_nth_kday_p(int argc, VALUE *argv, VALUE klass)
{
    VALUE vy, vm, vn, vk, vsg;
    VALUE argv2[5];

    rb_scan_args(argc, argv, "41", &vy, &vm, &vn, &vk, &vsg);

    argv2[0] = vy;
    argv2[1] = vm;
    argv2[2] = vn;
    argv2[3] = vk;
    if (argc < 5)
	argv2[4] = DBL2NUM(GREGORIAN);
    else
	argv2[4] = vsg;

    return valid_nth_kday_sub(5, argv2, klass, 1);
}