* ext/date/lib: moved from lib.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@31095 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

3 files changed, 3193 insertions, 0 deletions

diff --git a/ext/.document b/ext/.document
index 6f4f668ddf..e1b8ae2549 100644
--- a/ext/.document
+++ b/ext/.document
@@ -3,6 +3,8 @@
 bigdecimal/bigdecimal.c
 bigdecimal/lib
 coverage/coverage.c
+date/date_core.c
+date/lib
 digest/digest.c
 etc/etc.c
 fcntl/fcntl.c
diff --git a/ext/date/lib/date.rb b/ext/date/lib/date.rb
new file mode 100644
index 0000000000..66fa67a579
--- /dev/null
+++ b/ext/date/lib/date.rb
@@ -0,0 +1,1880 @@
+#
+# date.rb - date and time library
+#
+# Author: Tadayoshi Funaba 1998-2011
+#
+# Documentation: William Webber <william@williamwebber.com>
+#
+# == Overview
+#
+# This file provides two classes for working with
+# dates and times.
+#
+# The first class, Date, represents dates.
+# It works with years, months, weeks, and days.
+# See the Date class documentation for more details.
+#
+# The second, DateTime, extends Date to include hours,
+# minutes, seconds, and fractions of a second.  It
+# provides basic support for time zones.  See the
+# DateTime class documentation for more details.
+#
+# === Ways of calculating the date.
+#
+# In common usage, the date is reckoned in years since or
+# before the Common Era (CE/BCE, also known as AD/BC), then
+# as a month and day-of-the-month within the current year.
+# This is known as the *Civil* *Date*, and abbreviated
+# as +civil+ in the Date class.
+#
+# Instead of year, month-of-the-year,  and day-of-the-month,
+# the date can also be reckoned in terms of year and
+# day-of-the-year.  This is known as the *Ordinal* *Date*,
+# and is abbreviated as +ordinal+ in the Date class.  (Note
+# that referring to this as the Julian date is incorrect.)
+#
+# The date can also be reckoned in terms of year, week-of-the-year,
+# and day-of-the-week.  This is known as the *Commercial*
+# *Date*, and is abbreviated as +commercial+ in the
+# Date class.  The commercial week runs Monday (day-of-the-week
+# 1) to Sunday (day-of-the-week 7), in contrast to the civil
+# week which runs Sunday (day-of-the-week 0) to Saturday
+# (day-of-the-week 6).  The first week of the commercial year
+# starts on the Monday on or before January 1, and the commercial
+# year itself starts on this Monday, not January 1.
+#
+# For scientific purposes, it is convenient to refer to a date
+# simply as a day count, counting from an arbitrary initial
+# day.  The date first chosen for this was January 1, 4713 BCE.
+# A count of days from this date is the *Julian* *Day* *Number*
+# or *Julian* *Date*, which is abbreviated as +jd+ in the
+# Date class.  This is in local time, and counts from midnight
+# on the initial day.  The stricter usage is in UTC, and counts
+# from midday on the initial day.  This is referred to in the
+# Date class as the *Astronomical* *Julian* *Day* *Number*, and
+# abbreviated as +ajd+.  In the Date class, the Astronomical
+# Julian Day Number includes fractional days.
+#
+# Another absolute day count is the *Modified* *Julian* *Day*
+# *Number*, which takes November 17, 1858 as its initial day.
+# This is abbreviated as +mjd+ in the Date class.  There
+# is also an *Astronomical* *Modified* *Julian* *Day* *Number*,
+# which is in UTC and includes fractional days.  This is
+# abbreviated as +amjd+ in the Date class.  Like the Modified
+# Julian Day Number (and unlike the Astronomical Julian
+# Day Number), it counts from midnight.
+#
+# Alternative calendars such as the Ethiopic Solar Calendar,
+# the Islamic Lunar Calendar, or the French Revolutionary Calendar
+# are not supported by the Date class; nor are calendars that
+# are based on an Era different from the Common Era, such as
+# the Japanese Era.
+#
+# === Calendar Reform
+#
+# The standard civil year is 365 days long.  However, the
+# solar year is fractionally longer than this.  To account
+# for this, a *leap* *year* is occasionally inserted.  This
+# is a year with 366 days, the extra day falling on February 29.
+# In the early days of the civil calendar, every fourth
+# year without exception was a leap year.  This way of
+# reckoning leap years is the *Julian* *Calendar*.
+#
+# However, the solar year is marginally shorter than 365 1/4
+# days, and so the *Julian* *Calendar* gradually ran slow
+# over the centuries.  To correct this, every 100th year
+# (but not every 400th year) was excluded as a leap year.
+# This way of reckoning leap years, which we use today, is
+# the *Gregorian* *Calendar*.
+#
+# The Gregorian Calendar was introduced at different times
+# in different regions.  The day on which it was introduced
+# for a particular region is the *Day* *of* *Calendar*
+# *Reform* for that region.  This is abbreviated as +sg+
+# (for Start of Gregorian calendar) in the Date class.
+#
+# Two such days are of particular
+# significance.  The first is October 15, 1582, which was
+# the Day of Calendar Reform for Italy and most Catholic
+# countries.  The second is September 14, 1752, which was
+# the Day of Calendar Reform for England and its colonies
+# (including what is now the United States).  These two
+# dates are available as the constants Date::ITALY and
+# Date::ENGLAND, respectively.  (By comparison, Germany and
+# Holland, less Catholic than Italy but less stubborn than
+# England, changed over in 1698; Sweden in 1753; Russia not
+# till 1918, after the Revolution; and Greece in 1923.  Many
+# Orthodox churches still use the Julian Calendar.  A complete
+# list of Days of Calendar Reform can be found at
+# http://www.polysyllabic.com/GregConv.html.)
+#
+# Switching from the Julian to the Gregorian calendar
+# involved skipping a number of days to make up for the
+# accumulated lag, and the later the switch was (or is)
+# done, the more days need to be skipped.  So in 1582 in Italy,
+# 4th October was followed by 15th October, skipping 10 days; in 1752
+# in England, 2nd September was followed by 14th September, skipping
+# 11 days; and if I decided to switch from Julian to Gregorian
+# Calendar this midnight, I would go from 27th July 2003 (Julian)
+# today to 10th August 2003 (Gregorian) tomorrow, skipping
+# 13 days.  The Date class is aware of this gap, and a supposed
+# date that would fall in the middle of it is regarded as invalid.
+#
+# The Day of Calendar Reform is relevant to all date representations
+# involving years.  It is not relevant to the Julian Day Numbers,
+# except for converting between them and year-based representations.
+#
+# In the Date and DateTime classes, the Day of Calendar Reform or
+# +sg+ can be specified a number of ways.  First, it can be as
+# the Julian Day Number of the Day of Calendar Reform.  Second,
+# it can be using the constants Date::ITALY or Date::ENGLAND; these
+# are in fact the Julian Day Numbers of the Day of Calendar Reform
+# of the respective regions.  Third, it can be as the constant
+# Date::JULIAN, which means to always use the Julian Calendar.
+# Finally, it can be as the constant Date::GREGORIAN, which means
+# to always use the Gregorian Calendar.
+#
+# Note: in the Julian Calendar, New Years Day was March 25.  The
+# Date class does not follow this convention.
+#
+# === Offsets
+#
+# DateTime objects support a simple representation
+# of offsets.  Offsets are represented as an offset
+# from UTC (UTC is not identical GMT; GMT is a historical term),
+# as a fraction of a day.  This offset is the
+# how much local time is later (or earlier) than UTC.
+# As you travel east, the offset increases until you
+# reach the dateline in the middle of the Pacific Ocean;
+# as you travel west, the offset decreases.  This offset
+# is abbreviated as +of+ in the Date class.
+#
+# This simple representation of offsets does not take
+# into account the common practice of Daylight Savings
+# Time or Summer Time.
+#
+# Most DateTime methods return the date and the
+# time in local time.  The two exceptions are
+# #ajd() and #amjd(), which return the date and time
+# in UTC time, including fractional days.
+#
+# The Date class does not support offsets, in that
+# there is no way to create a Date object with non-utc offset.
+#
+# == Examples of use
+#
+# === Print out the date of every Sunday between two dates.
+#
+#     def print_sundays(d1, d2)
+#         d1 += 1 until d1.sunday?
+#         d1.step(d2, 7) do |d|
+#             puts d.strftime('%B %-d')
+#         end
+#     end
+#
+#     print_sundays(Date.new(2003, 4, 8), Date.new(2003, 5, 23))
+
+require 'date/format'
+
+# Class representing a date.
+#
+# See the documentation to the file date.rb for an overview.
+#
+# Internally, the date is represented as an Astronomical
+# Julian Day Number, +ajd+.  The Day of Calendar Reform, +sg+, is
+# also stored, for conversions to other date formats.  (There
+# is also an +of+ field for a time zone offset, but this
+# is only for the use of the DateTime subclass.)
+#
+# A new Date object is created using one of the object creation
+# class methods named after the corresponding date format, and the
+# arguments appropriate to that date format; for instance,
+# Date::civil() (aliased to Date::new()) with year, month,
+# and day-of-month, or Date::ordinal() with year and day-of-year.
+# All of these object creation class methods also take the
+# Day of Calendar Reform as an optional argument.
+#
+# Date objects are immutable once created.
+#
+# Once a Date has been created, date values
+# can be retrieved for the different date formats supported
+# using instance methods.  For instance, #mon() gives the
+# Civil month, #cwday() gives the Commercial day of the week,
+# and #yday() gives the Ordinal day of the year.  Date values
+# can be retrieved in any format, regardless of what format
+# was used to create the Date instance.
+#
+# The Date class includes the Comparable module, allowing
+# date objects to be compared and sorted, ranges of dates
+# to be created, and so forth.
+class Date
+
+  include Comparable
+
+  # Full month names, in English.  Months count from 1 to 12; a
+  # month's numerical representation indexed into this array
+  # gives the name of that month (hence the first element is nil).
+  MONTHNAMES = [nil] + %w(January February March April May June July
+			  August September October November December)
+
+  # Full names of days of the week, in English.  Days of the week
+  # count from 0 to 6 (except in the commercial week); a day's numerical
+  # representation indexed into this array gives the name of that day.
+  DAYNAMES = %w(Sunday Monday Tuesday Wednesday Thursday Friday Saturday)
+
+  # Abbreviated month names, in English.
+  ABBR_MONTHNAMES = [nil] + %w(Jan Feb Mar Apr May Jun
+			       Jul Aug Sep Oct Nov Dec)
+
+  # Abbreviated day names, in English.
+  ABBR_DAYNAMES = %w(Sun Mon Tue Wed Thu Fri Sat)
+
+  [MONTHNAMES, DAYNAMES, ABBR_MONTHNAMES, ABBR_DAYNAMES].each do |xs|
+    xs.each{|x| x.freeze unless x.nil?}.freeze
+  end
+
+  # now only for marshal dumped
+  class Infinity < Numeric # :nodoc:
+
+    include Comparable
+
+    def initialize(d=1) @d = d <=> 0 end
+
+    def d() @d end
+
+    protected :d
+
+    def zero? () false end
+    def finite? () false end
+    def infinite? () d.nonzero? end
+    def nan? () d.zero? end
+
+    def abs() self.class.new end
+
+    def -@ () self.class.new(-d) end
+    def +@ () self.class.new(+d) end
+
+    def <=> (other)
+      case other
+      when Infinity; return d <=> other.d
+      when Numeric; return d
+      else
+	begin
+	  l, r = other.coerce(self)
+	  return l <=> r
+	rescue NoMethodError
+	end
+      end
+      nil
+    end
+
+    def coerce(other)
+      case other
+      when Numeric; return -d, d
+      else
+	super
+      end
+    end
+
+    def to_f
+      return 0 if @d == 0
+      if @d > 0
+	Float::INFINITY
+      else
+	-Float::INFINITY
+      end
+    end
+
+  end
+
+  # The Julian Day Number of the Day of Calendar Reform for Italy
+  # and the Catholic countries.
+  ITALY     = 2299161 # 1582-10-15
+
+  # The Julian Day Number of the Day of Calendar Reform for England
+  # and her Colonies.
+  ENGLAND   = 2361222 # 1752-09-14
+
+  # A constant used to indicate that a Date should always use the
+  # Julian calendar.
+  JULIAN    =  Float::INFINITY
+
+  # A constant used to indicate that a Date should always use the
+  # Gregorian calendar.
+  GREGORIAN = -Float::INFINITY
+
+  HALF_DAYS_IN_DAY       = Rational(1, 2) # :nodoc:
+  HOURS_IN_DAY           = Rational(1, 24) # :nodoc:
+  MINUTES_IN_DAY         = Rational(1, 1440) # :nodoc:
+  SECONDS_IN_DAY         = Rational(1, 86400) # :nodoc:
+  MILLISECONDS_IN_DAY    = Rational(1, 86400*10**3) # :nodoc:
+  NANOSECONDS_IN_DAY     = Rational(1, 86400*10**9) # :nodoc:
+  MILLISECONDS_IN_SECOND = Rational(1, 10**3) # :nodoc:
+  NANOSECONDS_IN_SECOND  = Rational(1, 10**9) # :nodoc:
+
+  MJD_EPOCH_IN_AJD       = Rational(4800001, 2) # 1858-11-17 # :nodoc:
+  UNIX_EPOCH_IN_AJD      = Rational(4881175, 2) # 1970-01-01 # :nodoc:
+  MJD_EPOCH_IN_CJD       = 2400001 # :nodoc:
+  UNIX_EPOCH_IN_CJD      = 2440588 # :nodoc:
+  LD_EPOCH_IN_CJD        = 2299160 # :nodoc:
+
+  t = Module.new do
+
+    private
+
+    def find_fdoy(y, sg) # :nodoc:
+      j = nil
+      1.upto(31) do |d|
+	break if j = _valid_civil?(y, 1, d, sg)
+      end
+      j
+    end
+
+    def find_ldoy(y, sg) # :nodoc:
+      j = nil
+      31.downto(1) do |d|
+	break if j = _valid_civil?(y, 12, d, sg)
+      end
+      j
+    end
+
+    def find_fdom(y, m, sg) # :nodoc:
+      j = nil
+      1.upto(31) do |d|
+	break if j = _valid_civil?(y, m, d, sg)
+      end
+      j
+    end
+
+    def find_ldom(y, m, sg) # :nodoc:
+      j = nil
+      31.downto(1) do |d|
+	break if j = _valid_civil?(y, m, d, sg)
+      end
+      j
+    end
+
+    # Convert an Ordinal Date to a Julian Day Number.
+    #
+    # +y+ and +d+ are the year and day-of-year to convert.
+    # +sg+ specifies the Day of Calendar Reform.
+    #
+    # Returns the corresponding Julian Day Number.
+    def ordinal_to_jd(y, d, sg=GREGORIAN) # :nodoc:
+      find_fdoy(y, sg) + d - 1
+    end
+
+    # Convert a Julian Day Number to an Ordinal Date.
+    #
+    # +jd+ is the Julian Day Number to convert.
+    # +sg+ specifies the Day of Calendar Reform.
+    #
+    # Returns the corresponding Ordinal Date as
+    # [year, day_of_year]
+    def jd_to_ordinal(jd, sg=GREGORIAN) # :nodoc:
+      y = jd_to_civil(jd, sg)[0]
+      j = find_fdoy(y, sg)
+      doy = jd - j + 1
+      return y, doy
+    end
+
+    # Convert a Civil Date to a Julian Day Number.
+    # +y+, +m+, and +d+ are the year, month, and day of the
+    # month.  +sg+ specifies the Day of Calendar Reform.
+    #
+    # Returns the corresponding Julian Day Number.
+    def civil_to_jd(y, m, d, sg=GREGORIAN) # :nodoc:
+      if m <= 2
+	y -= 1
+	m += 12
+      end
+      a = (y / 100.0).floor
+      b = 2 - a + (a / 4.0).floor
+      jd = (365.25 * (y + 4716)).floor +
+	(30.6001 * (m + 1)).floor +
+	d + b - 1524
+      if jd < sg
+	jd -= b
+      end
+      jd
+    end
+
+    # Convert a Julian Day Number to a Civil Date.  +jd+ is
+    # the Julian Day Number. +sg+ specifies the Day of
+    # Calendar Reform.
+    #
+    # Returns the corresponding [year, month, day_of_month]
+    # as a three-element array.
+    def jd_to_civil(jd, sg=GREGORIAN) # :nodoc:
+      if jd < sg
+	a = jd
+      else
+	x = ((jd - 1867216.25) / 36524.25).floor
+	a = jd + 1 + x - (x / 4.0).floor
+      end
+      b = a + 1524
+      c = ((b - 122.1) / 365.25).floor
+      d = (365.25 * c).floor
+      e = ((b - d) / 30.6001).floor
+      dom = b - d - (30.6001 * e).floor
+      if e <= 13
+	m = e - 1
+	y = c - 4716
+      else
+	m = e - 13
+	y = c - 4715
+      end
+      return y, m, dom
+    end
+
+    # Convert a Commercial Date to a Julian Day Number.
+    #
+    # +y+, +w+, and +d+ are the (commercial) year, week of the year,
+    # and day of the week of the Commercial Date to convert.
+    # +sg+ specifies the Day of Calendar Reform.
+    def commercial_to_jd(y, w, d, sg=GREGORIAN) # :nodoc:
+      j = find_fdoy(y, sg) + 3
+      (j - (((j - 1) + 1) % 7)) +
+	7 * (w - 1) +
+	(d - 1)
+    end
+
+    # Convert a Julian Day Number to a Commercial Date
+    #
+    # +jd+ is the Julian Day Number to convert.
+    # +sg+ specifies the Day of Calendar Reform.
+    #
+    # Returns the corresponding Commercial Date as
+    # [commercial_year, week_of_year, day_of_week]
+    def jd_to_commercial(jd, sg=GREGORIAN) # :nodoc:
+      a = jd_to_civil(jd - 3, sg)[0]
+      j = commercial_to_jd(a + 1, 1, 1, sg)
+      if jd >= j
+	y = a + 1
+      else
+	j = commercial_to_jd(a, 1, 1, sg)
+	y = a
+      end
+      w = 1 + ((jd - j) / 7).floor
+      d = (jd + 1) % 7
+      d = 7 if d == 0
+      return y, w, d
+    end
+
+    def weeknum_to_jd(y, w, d, f=0, sg=GREGORIAN) # :nodoc:
+      a = find_fdoy(y, sg) + 6
+      (a - ((a - f) + 1) % 7 - 7) + 7 * w + d
+    end
+
+    def jd_to_weeknum(jd, f=0, sg=GREGORIAN) # :nodoc:
+      y, _, d = jd_to_civil(jd, sg)
+      a = find_fdoy(y, sg) + 6
+      w, d = (jd - (a - ((a - f) + 1) % 7) + 7).divmod(7)
+      return y, w, d
+    end
+
+    def nth_kday_to_jd(y, m, n, k, sg=GREGORIAN) # :nodoc:
+      j = if n > 0
+	    find_fdom(y, m, sg) - 1
+	  else
+	    find_ldom(y, m, sg) + 7
+	  end
+      (j - (((j - k) + 1) % 7)) + 7 * n
+    end
+
+    def jd_to_nth_kday(jd, sg=GREGORIAN) # :nodoc:
+      y, m, = jd_to_civil(jd, sg)
+      j = find_fdom(y, m, sg)
+      return y, m, ((jd - j) / 7).floor + 1, jd_to_wday(jd)
+    end
+
+    # Convert an Astronomical Julian Day Number to a (civil) Julian
+    # Day Number.
+    #
+    # +ajd+ is the Astronomical Julian Day Number to convert.
+    # +of+ is the offset from UTC as a fraction of a day (defaults to 0).
+    #
+    # Returns the (civil) Julian Day Number as [day_number,
+    # fraction] where +fraction+ is always 1/2.
+    def ajd_to_jd(ajd, of=0) (ajd + of + HALF_DAYS_IN_DAY).divmod(1) end # :nodoc:
+
+    # Convert a (civil) Julian Day Number to an Astronomical Julian
+    # Day Number.
+    #
+    # +jd+ is the Julian Day Number to convert, and +fr+ is a
+    # fractional day.
+    # +of+ is the offset from UTC as a fraction of a day (defaults to 0).
+    #
+    # Returns the Astronomical Julian Day Number as a single
+    # numeric value.
+    def jd_to_ajd(jd, fr, of=0) jd + fr - of - HALF_DAYS_IN_DAY end # :nodoc:
+
+    # Convert a fractional day +fr+ to [hours, minutes, seconds,
+    # fraction_of_a_second]
+    def day_fraction_to_time(fr) # :nodoc:
+      ss,  fr = fr.divmod(SECONDS_IN_DAY) # 4p
+      h,   ss = ss.divmod(3600)
+      min, s  = ss.divmod(60)
+      return h, min, s, fr * 86400
+    end
+
+    def day_fraction_to_time_wo_sf(fr) # :nodoc:
+      ss      = fr.div(SECONDS_IN_DAY) # 4p
+      h,   ss = ss.divmod(3600)
+      min, s  = ss.divmod(60)
+      return h, min, s
+    end
+
+    # Convert an +h+ hour, +min+ minutes, +s+ seconds period
+    # to a fractional day.
+    begin
+      Rational(Rational(1, 2), 2) # a challenge
+
+      def time_to_day_fraction(h, min, s)
+	Rational(h * 3600 + min * 60 + s, 86400) # 4p
+      end
+    rescue
+      def time_to_day_fraction(h, min, s)
+	if Integer === h && Integer === min && Integer === s
+	  Rational(h * 3600 + min * 60 + s, 86400) # 4p
+	else
+	  (h * 3600 + min * 60 + s).to_r/86400 # 4p
+	end
+      end
+    end
+
+    # Convert an Astronomical Modified Julian Day Number to an
+    # Astronomical Julian Day Number.
+    def amjd_to_ajd(amjd) amjd + MJD_EPOCH_IN_AJD end # :nodoc:
+
+    # Convert an Astronomical Julian Day Number to an
+    # Astronomical Modified Julian Day Number.
+    def ajd_to_amjd(ajd) ajd - MJD_EPOCH_IN_AJD end # :nodoc:
+
+    # Convert a Modified Julian Day Number to a Julian
+    # Day Number.
+    def mjd_to_jd(mjd) mjd + MJD_EPOCH_IN_CJD end # :nodoc:
+
+    # Convert a Julian Day Number to a Modified Julian Day
+    # Number.
+    def jd_to_mjd(jd) jd - MJD_EPOCH_IN_CJD end # :nodoc:
+
+    # Convert a count of the number of days since the adoption
+    # of the Gregorian Calendar (in Italy) to a Julian Day Number.
+    def ld_to_jd(ld) ld +  LD_EPOCH_IN_CJD end # :nodoc:
+
+    # Convert a Julian Day Number to the number of days since
+    # the adoption of the Gregorian Calendar (in Italy).
+    def jd_to_ld(jd) jd -  LD_EPOCH_IN_CJD end # :nodoc:
+
+    # Convert a Julian Day Number to the day of the week.
+    #
+    # Sunday is day-of-week 0; Saturday is day-of-week 6.
+    def jd_to_wday(jd) (jd + 1) % 7 end # :nodoc:
+
+    # Is +jd+ a valid Julian Day Number?
+    #
+    # If it is, returns it.  In fact, any value is treated as a valid
+    # Julian Day Number.
+    def _valid_jd? (jd, sg=GREGORIAN) jd end # :nodoc:
+
+    # Do the year +y+ and day-of-year +d+ make a valid Ordinal Date?
+    # Returns the corresponding Julian Day Number if they do, or
+    # nil if they don't.
+    #
+    # +d+ can be a negative number, in which case it counts backwards
+    # from the end of the year (-1 being the last day of the year).
+    # No year wraparound is performed, however, so valid values of
+    # +d+ are -365 .. -1, 1 .. 365 on a non-leap-year,
+    # -366 .. -1, 1 .. 366 on a leap year.
+    # A date falling in the period skipped in the Day of Calendar Reform
+    # adjustment is not valid.
+    #
+    # +sg+ specifies the Day of Calendar Reform.
+    def _valid_ordinal? (y, d, sg=GREGORIAN) # :nodoc:
+      if d < 0
+	return unless j = find_ldoy(y, sg)
+	ny, nd = jd_to_ordinal(j + d + 1, sg)
+	return unless ny == y
+	d = nd
+      end
+      jd = ordinal_to_jd(y, d, sg)
+      return unless [y, d] == jd_to_ordinal(jd, sg)
+      jd
+    end
+
+    # Do year +y+, month +m+, and day-of-month +d+ make a
+    # valid Civil Date?  Returns the corresponding Julian
+    # Day Number if they do, nil if they don't.
+    #
+    # +m+ and +d+ can be negative, in which case they count
+    # backwards from the end of the year and the end of the
+    # month respectively.  No wraparound is performed, however,
+    # and invalid values cause an ArgumentError to be raised.
+    # A date falling in the period skipped in the Day of Calendar
+    # Reform adjustment is not valid.
+    #
+    # +sg+ specifies the Day of Calendar Reform.
+    def _valid_civil? (y, m, d, sg=GREGORIAN) # :nodoc:
+      if m < 0
+	m += 13
+      end
+      if d < 0
+	return unless j = find_ldom(y, m, sg)
+	ny, nm, nd = jd_to_civil(j + d + 1, sg)
+	return unless [ny, nm] == [y, m]
+	d = nd
+      end
+      jd = civil_to_jd(y, m, d, sg)
+      return unless [y, m, d] == jd_to_civil(jd, sg)
+      jd
+    end
+
+    # Do year +y+, week-of-year +w+, and day-of-week +d+ make a
+    # valid Commercial Date?  Returns the corresponding Julian
+    # Day Number if they do, nil if they don't.
+    #
+    # Monday is day-of-week 1; Sunday is day-of-week 7.
+    #
+    # +w+ and +d+ can be negative, in which case they count
+    # backwards from the end of the year and the end of the
+    # week respectively.  No wraparound is performed, however,
+    # and invalid values cause an ArgumentError to be raised.
+    # A date falling in the period skipped in the Day of Calendar
+    # Reform adjustment is not valid.
+    #
+    # +sg+ specifies the Day of Calendar Reform.
+    def _valid_commercial? (y, w, d, sg=GREGORIAN) # :nodoc:
+      if d < 0
+	d += 8
+      end
+      if w < 0
+	ny, nw, =
+	  jd_to_commercial(commercial_to_jd(y + 1, 1, 1, sg) + w * 7, sg)
+	return unless ny == y
+	w = nw
+      end
+      jd = commercial_to_jd(y, w, d, sg)
+      return unless [y, w, d] == jd_to_commercial(jd, sg)
+      jd
+    end
+
+    def _valid_weeknum? (y, w, d, f, sg=GREGORIAN) # :nodoc:
+      if d < 0
+	d += 7
+      end
+      if w < 0
+	ny, nw, =
+	  jd_to_weeknum(weeknum_to_jd(y + 1, 1, f, f, sg) + w * 7, f, sg)
+	return unless ny == y
+	w = nw
+      end
+      jd = weeknum_to_jd(y, w, d, f, sg)
+      return unless [y, w, d] == jd_to_weeknum(jd, f, sg)
+      jd
+    end
+
+    def _valid_nth_kday? (y, m, n, k, sg=GREGORIAN) # :nodoc:
+      if k < 0
+	k += 7
+      end
+      if n < 0
+	ny, nm = (y * 12 + m).divmod(12)
+	nm,    = (nm + 1)    .divmod(1)
+	ny, nm, nn, =
+	  jd_to_nth_kday(nth_kday_to_jd(ny, nm, 1, k, sg) + n * 7, sg)
+	return unless [ny, nm] == [y, m]
+	n = nn
+      end
+      jd = nth_kday_to_jd(y, m, n, k, sg)
+      return unless [y, m, n, k] == jd_to_nth_kday(jd, sg)
+      jd
+    end
+
+    # Do hour +h+, minute +min+, and second +s+ constitute a valid time?
+    #
+    # If they do, returns their value as a fraction of a day.  If not,
+    # returns nil.
+    #
+    # The 24-hour clock is used.  Negative values of +h+, +min+, and
+    # +sec+ are treating as counting backwards from the end of the
+    # next larger unit (e.g. a +min+ of -2 is treated as 58).  No
+    # wraparound is performed.
+    def _valid_time? (h, min, s) # :nodoc:
+      h   += 24 if h   < 0
+      min += 60 if min < 0
+      s   += 60 if s   < 0
+      return unless ((0...24) === h &&
+		     (0...60) === min &&
+		     (0...60) === s) ||
+		     (24 == h &&
+		       0 == min &&
+		       0 == s)
+      time_to_day_fraction(h, min, s)
+    end
+
+  end
+
+  extend  t
+  include t
+
+  # Is a year a leap year in the Julian calendar?
+  #
+  # All years divisible by 4 are leap years in the Julian calendar.
+  def self.julian_leap? (y) y % 4 == 0 end
+
+  # Is a year a leap year in the Gregorian calendar?
+  #
+  # All years divisible by 4 are leap years in the Gregorian calendar,
+  # except for years divisible by 100 and not by 400.
+  def self.gregorian_leap? (y) y % 4 == 0 && y % 100 != 0 || y % 400 == 0 end
+
+  class << self; alias_method :leap?, :gregorian_leap? end
+
+  def self.valid_jd_r? (jd, sg=ITALY)
+    !!_valid_jd?(jd, sg)
+  end
+
+  private_class_method :valid_jd_r?
+
+  def self.valid_ordinal_r? (y, d, sg=ITALY)
+    !!_valid_ordinal?(y, d, sg)
+  end
+
+  private_class_method :valid_ordinal_r?
+
+  def self.valid_civil_r? (y, m, d, sg=ITALY)
+    !!_valid_civil?(y, m, d, sg)
+  end
+
+  private_class_method :valid_civil_r?
+
+  def self.valid_commercial_r? (y, w, d, sg=ITALY)
+    !!_valid_commercial?(y, w, d, sg)
+  end
+
+  private_class_method :valid_commercial_r?
+
+  def self.valid_weeknum? (y, w, d, f, sg=ITALY) # :nodoc:
+    !!_valid_weeknum?(y, w, d, f, sg)
+  end
+
+  private_class_method :valid_weeknum?
+
+  def self.valid_nth_kday? (y, m, n, k, sg=ITALY) # :nodoc:
+    !!_valid_nth_kday?(y, m, n, k, sg)
+  end
+
+  private_class_method :valid_nth_kday?
+
+  def self.valid_time? (h, min, s) # :nodoc:
+    !!_valid_time?(h, min, s)
+  end
+
+  private_class_method :valid_time?
+
+  def self.new!(ajd=0, of=0, sg=ITALY)
+    jd, df = ajd_to_jd(ajd, 0)
+    if !(Fixnum === jd) ||
+	jd < sg || df !=0 || of != 0 ||
+        jd < -327 || jd > 366963925
+      return new_r!(ajd, of, sg)
+    end
+    new_l!(jd, sg)
+  end
+
+  # Create a new Date object from a Julian Day Number.
+  #
+  # +jd+ is the Julian Day Number; if not specified, it defaults to
+  # 0.
+  # +sg+ specifies the Day of Calendar Reform.
+  def self.jd_r(jd=0, sg=ITALY) # :nodoc:
+    jd = _valid_jd?(jd, sg)
+    new_r!(jd_to_ajd(jd, 0, 0), 0, sg)
+  end
+
+  private_class_method :jd_r
+
+  # Create a new Date object from an Ordinal Date, specified
+  # by year +y+ and day-of-year +d+. +d+ can be negative,
+  # in which it counts backwards from the end of the year.
+  # No year wraparound is performed, however.  An invalid
+  # value for +d+ results in an ArgumentError being raised.
+  #
+  # +y+ defaults to -4712, and +d+ to 1; this is Julian Day
+  # Number day 0.
+  #
+  # +sg+ specifies the Day of Calendar Reform.
+  def self.ordinal_r(y=-4712, d=1, sg=ITALY) # :nodoc:
+    unless jd = _valid_ordinal?(y, d, sg)
+      raise ArgumentError, 'invalid date'
+    end
+    new_r!(jd_to_ajd(jd, 0, 0), 0, sg)
+  end
+
+  private_class_method :ordinal_r
+
+  # Create a new Date object for the Civil Date specified by
+  # year +y+, month +m+, and day-of-month +d+.
+  #
+  # +m+ and +d+ can be negative, in which case they count
+  # backwards from the end of the year and the end of the
+  # month respectively.  No wraparound is performed, however,
+  # and invalid values cause an ArgumentError to be raised.
+  # can be negative
+  #
+  # +y+ defaults to -4712, +m+ to 1, and +d+ to 1; this is
+  # Julian Day Number day 0.
+  #
+  # +sg+ specifies the Day of Calendar Reform.
+  def self.civil_r(y=-4712, m=1, d=1, sg=ITALY) # :nodoc:
+    unless jd = _valid_civil?(y, m, d, sg)
+      raise ArgumentError, 'invalid date'
+    end
+    new_r!(jd_to_ajd(jd, 0, 0), 0, sg)
+  end
+
+  private_class_method :civil_r
+
+  # Create a new Date object for the Commercial Date specified by
+  # year +y+, week-of-year +w+, and day-of-week +d+.
+  #
+  # Monday is day-of-week 1; Sunday is day-of-week 7.
+  #
+  # +w+ and +d+ can be negative, in which case they count
+  # backwards from the end of the year and the end of the
+  # week respectively.  No wraparound is performed, however,
+  # and invalid values cause an ArgumentError to be raised.
+  #
+  # +y+ defaults to -4712, +w+ to 1, and +d+ to 1; this is
+  # Julian Day Number day 0.
+  #
+  # +sg+ specifies the Day of Calendar Reform.
+  def self.commercial_r(y=-4712, w=1, d=1, sg=ITALY) # :nodoc:
+    unless jd = _valid_commercial?(y, w, d, sg)
+      raise ArgumentError, 'invalid date'
+    end
+    new_r!(jd_to_ajd(jd, 0, 0), 0, sg)
+  end
+
+  private_class_method :commercial_r
+
+  def self.weeknum(y=-4712, w=0, d=1, f=0, sg=ITALY)
+    unless jd = _valid_weeknum?(y, w, d, f, sg)
+      raise ArgumentError, 'invalid date'
+    end
+    new!(jd_to_ajd(jd, 0, 0), 0, sg)
+  end
+
+  private_class_method :weeknum
+
+  def self.nth_kday(y=-4712, m=1, n=1, k=1, sg=ITALY)
+    unless jd = _valid_nth_kday?(y, m, n, k, sg)
+      raise ArgumentError, 'invalid date'
+    end
+    new!(jd_to_ajd(jd, 0, 0), 0, sg)
+  end
+
+  private_class_method :nth_kday
+
+  def self.rewrite_frags(elem) # :nodoc:
+    elem ||= {}
+    if seconds = elem[:seconds]
+      d,   fr = seconds.divmod(86400)
+      h,   fr = fr.divmod(3600)
+      min, fr = fr.divmod(60)
+      s,   fr = fr.divmod(1)
+      elem[:jd] = UNIX_EPOCH_IN_CJD + d
+      elem[:hour] = h
+      elem[:min] = min
+      elem[:sec] = s
+      elem[:sec_fraction] = fr
+      elem.delete(:seconds)
+      elem.delete(:offset)
+    end
+    elem
+  end
+
+  private_class_method :rewrite_frags
+
+  def self.complete_frags(elem) # :nodoc:
+    i = 0
+    g = [[:time, [:hour, :min, :sec]],
+	 [nil, [:jd]],
+	 [:ordinal, [:year, :yday, :hour, :min, :sec]],
+	 [:civil, [:year, :mon, :mday, :hour, :min, :sec]],
+	 [:commercial, [:cwyear, :cweek, :cwday, :hour, :min, :sec]],
+	 [:wday, [:wday, :hour, :min, :sec]],
+	 [:wnum0, [:year, :wnum0, :wday, :hour, :min, :sec]],
+	 [:wnum1, [:year, :wnum1, :wday, :hour, :min, :sec]],
+	 [nil, [:cwyear, :cweek, :wday, :hour, :min, :sec]],
+	 [nil, [:year, :wnum0, :cwday, :hour, :min, :sec]],
+	 [nil, [:year, :wnum1, :cwday, :hour, :min, :sec]]].
+      collect{|k, a| e = elem.values_at(*a).compact; [k, a, e]}.
+      select{|k, a, e| e.size > 0}.
+      sort_by{|k, a, e| [e.size, i -= 1]}.last
+
+    d = nil
+
+    if g && g[0] && (g[1].size - g[2].size) != 0
+      d ||= Date.today
+
+      case g[0]
+      when :ordinal
+	elem[:year] ||= d.year
+	elem[:yday] ||= 1
+      when :civil
+	g[1].each do |e|
+	  break if elem[e]
+	  elem[e] = d.__send__(e)
+	end
+	elem[:mon]  ||= 1
+	elem[:mday] ||= 1
+      when :commercial
+	g[1].each do |e|
+	  break if elem[e]
+	  elem[e] = d.__send__(e)
+	end
+	elem[:cweek] ||= 1
+	elem[:cwday] ||= 1
+      when :wday
+	elem[:jd] ||= (d - d.wday + elem[:wday]).jd
+      when :wnum0
+	g[1].each do |e|
+	  break if elem[e]
+	  elem[e] = d.__send__(e)
+	end
+	elem[:wnum0] ||= 0
+	elem[:wday]  ||= 0
+      when :wnum1
+	g[1].each do |e|
+	  break if elem[e]
+	  elem[e] = d.__send__(e)
+	end
+	elem[:wnum1] ||= 0
+	elem[:wday]  ||= 1
+      end
+    end
+
+    if g && g[0] == :time
+      if self <= DateTime
+	d ||= Date.today
+	elem[:jd] ||= d.jd
+      end
+    end
+
+    elem[:hour] ||= 0
+    elem[:min]  ||= 0
+    elem[:sec]  ||= 0
+    elem[:sec] = [elem[:sec], 59].min
+
+    elem
+  end
+
+  private_class_method :complete_frags
+
+  def self.valid_date_frags?(elem, sg) # :nodoc:
+    catch :jd do
+      a = elem.values_at(:jd)
+      if a.all?
+	if jd = _valid_jd?(*(a << sg))
+	  throw :jd, jd
+	end
+      end
+
+      a = elem.values_at(:year, :yday)
+      if a.all?
+	if jd = _valid_ordinal?(*(a << sg))
+	  throw :jd, jd
+	end
+      end
+
+      a = elem.values_at(:year, :mon, :mday)
+      if a.all?
+	if jd = _valid_civil?(*(a << sg))
+	  throw :jd, jd
+	end
+      end
+
+      a = elem.values_at(:cwyear, :cweek, :cwday)
+      if a[2].nil? && elem[:wday]
+	a[2] = elem[:wday].nonzero? || 7
+      end
+      if a.all?
+	if jd = _valid_commercial?(*(a << sg))
+	  throw :jd, jd
+	end
+      end
+
+      a = elem.values_at(:year, :wnum0, :wday)
+      if a[2].nil? && elem[:cwday]
+	a[2] = elem[:cwday] % 7
+      end
+      if a.all?
+	if jd = _valid_weeknum?(*(a << 0 << sg))
+	  throw :jd, jd
+	end
+      end
+
+      a = elem.values_at(:year, :wnum1, :wday)
+      if a[2]
+	a[2] = (a[2] - 1) % 7
+      end
+      if a[2].nil? && elem[:cwday]
+	a[2] = (elem[:cwday] - 1) % 7
+      end
+      if a.all?
+	if jd = _valid_weeknum?(*(a << 1 << sg))
+	  throw :jd, jd
+	end
+      end
+    end
+  end
+
+  private_class_method :valid_date_frags?
+
+  def self.valid_time_frags? (elem) # :nodoc:
+    h, min, s = elem.values_at(:hour, :min, :sec)
+    _valid_time?(h, min, s)
+  end
+
+  private_class_method :valid_time_frags?
+
+  def self.new_by_frags(elem, sg) # :nodoc:
+    elem = rewrite_frags(elem)
+    elem = complete_frags(elem)
+    unless jd = valid_date_frags?(elem, sg)
+      raise ArgumentError, 'invalid date'
+    end
+    new!(jd_to_ajd(jd, 0, 0), 0, sg)
+  end
+
+  private_class_method :new_by_frags
+
+  # Create a new Date object by parsing from a String
+  # according to a specified format.
+  #
+  # +str+ is a String holding a date representation.
+  # +fmt+ is the format that the date is in.  See
+  # date/format.rb for details on supported formats.
+  #
+  # The default +str+ is '-4712-01-01', and the default
+  # +fmt+ is '%F', which means Year-Month-Day_of_Month.
+  # This gives Julian Day Number day 0.
+  #
+  # +sg+ specifies the Day of Calendar Reform.
+  #
+  # An ArgumentError will be raised if +str+ cannot be
+  # parsed.
+  def self.strptime(str='-4712-01-01', fmt='%F', sg=ITALY)
+    elem = _strptime(str, fmt)
+    new_by_frags(elem, sg)
+  end
+
+  # Create a new Date object by parsing from a String,
+  # without specifying the format.
+  #
+  # +str+ is a String holding a date representation.
+  # +comp+ specifies whether to interpret 2-digit years
+  # as 19XX (>= 69) or 20XX (< 69); the default is to.
+  # The method will attempt to parse a date from the String
+  # using various heuristics; see #_parse in date/format.rb
+  # for more details.  If parsing fails, an ArgumentError
+  # will be raised.
+  #
+  # The default +str+ is '-4712-01-01'; this is Julian
+  # Day Number day 0.
+  #
+  # +sg+ specifies the Day of Calendar Reform.
+  def self.parse(str='-4712-01-01', comp=true, sg=ITALY)
+    elem = _parse(str, comp)
+    new_by_frags(elem, sg)
+  end
+
+  def self.iso8601(str='-4712-01-01', sg=ITALY) # :nodoc:
+    elem = _iso8601(str)
+    new_by_frags(elem, sg)
+  end
+
+  def self.rfc3339(str='-4712-01-01T00:00:00+00:00', sg=ITALY) # :nodoc:
+    elem = _rfc3339(str)
+    new_by_frags(elem, sg)
+  end
+
+  def self.xmlschema(str='-4712-01-01', sg=ITALY) # :nodoc:
+    elem = _xmlschema(str)
+    new_by_frags(elem, sg)
+  end
+
+  def self.rfc2822(str='Mon, 1 Jan -4712 00:00:00 +0000', sg=ITALY) # :nodoc:
+    elem = _rfc2822(str)
+    new_by_frags(elem, sg)
+  end
+
+  class << self; alias_method :rfc822, :rfc2822 end
+
+  def self.httpdate(str='Mon, 01 Jan -4712 00:00:00 GMT', sg=ITALY) # :nodoc:
+    elem = _httpdate(str)
+    new_by_frags(elem, sg)
+  end
+
+  def self.jisx0301(str='-4712-01-01', sg=ITALY) # :nodoc:
+    elem = _jisx0301(str)
+    new_by_frags(elem, sg)
+  end
+
+  class << self
+
+    def once(*ids) # :nodoc: -- restricted
+      for id in ids
+	module_eval <<-"end;"
+	  alias_method :__#{id.object_id}__, :#{id.to_s}
+	  private :__#{id.object_id}__
+	  def #{id.to_s}(*args)
+	    __ca__[#{id.object_id}] ||= __#{id.object_id}__(*args)
+	  end
+	end;
+      end
+    end # <<dummy
+
+    private :once
+
+  end
+
+  # Get the date as an Astronomical Modified Julian Day Number.
+  def amjd_r() ajd_to_amjd(ajd) end
+
+  once :amjd_r
+
+  def daynum() ajd_to_jd(ajd, offset) end
+
+  once :daynum
+  private :daynum
+
+  # Get the date as a Julian Day Number.
+  def jd_r() daynum[0] end # :nodoc:
+
+  # Get any fractional day part of the date.
+  def day_fraction_r() daynum[1] end # :nodoc:
+
+  # Get the date as a Modified Julian Day Number.
+  def mjd_r() jd_to_mjd(jd) end # :nodoc:
+
+  # Get the date as the number of days since the Day of Calendar
+  # Reform (in Italy and the Catholic countries).
+  def ld_r() jd_to_ld(jd) end # :nodoc:
+
+  once :jd_r, :day_fraction_r, :mjd_r, :ld_r
+  private :jd_r, :day_fraction_r, :mjd_r, :ld_r
+
+  # Get the date as a Civil Date, [year, month, day_of_month]
+  def civil() jd_to_civil(jd, start) end # :nodoc:
+
+  # Get the date as an Ordinal Date, [year, day_of_year]
+  def ordinal() jd_to_ordinal(jd, start) end # :nodoc:
+
+  # Get the date as a Commercial Date, [year, week_of_year, day_of_week]
+  def commercial() jd_to_commercial(jd, start) end # :nodoc:
+
+  def weeknum0() jd_to_weeknum(jd, 0, start) end # :nodoc:
+  def weeknum1() jd_to_weeknum(jd, 1, start) end # :nodoc:
+
+  once :civil, :ordinal, :commercial, :weeknum0, :weeknum1
+  private :civil, :ordinal, :commercial, :weeknum0, :weeknum1
+
+  # Get the year of this date.
+  def year_r() civil[0] end # :nodoc:
+
+  # Get the day-of-the-year of this date.
+  #
+  # January 1 is day-of-the-year 1
+  def yday_r() ordinal[1] end # :nodoc:
+
+  # Get the month of this date.
+  #
+  # January is month 1.
+  def mon_r() civil[1] end # :nodoc:
+
+  # Get the day-of-the-month of this date.
+  def mday_r() civil[2] end # :nodoc:
+
+  private :year_r, :yday_r, :mon_r, :mday_r
+
+  def wnum0_r() weeknum0[1] end # :nodoc:
+  def wnum1_r() weeknum1[1] end # :nodoc:
+
+  private :wnum0_r, :wnum1_r
+
+  # Get the time of this date as [hours, minutes, seconds,
+  # fraction_of_a_second]
+  def time() day_fraction_to_time(day_fraction) end # :nodoc:
+  def time_wo_sf() day_fraction_to_time_wo_sf(day_fraction) end # :nodoc:
+  def time_sf() day_fraction % SECONDS_IN_DAY * 86400 end # :nodoc:
+
+  once :time, :time_wo_sf, :time_sf
+  private :time, :time_wo_sf, :time_sf
+
+  # Get the hour of this date.
+  def hour_r() time_wo_sf[0] end # :nodoc: # 4p
+
+  # Get the minute of this date.
+  def min_r() time_wo_sf[1] end # :nodoc: # 4p
+
+  # Get the second of this date.
+  def sec_r() time_wo_sf[2] end # :nodoc: # 4p
+
+  # Get the fraction-of-a-second of this date.
+  def sec_fraction_r() time_sf end # 4p
+
+  private :hour_r, :min_r, :sec_r, :sec_fraction_r
+
+  def zone_r # :nodoc: # 4p - strftime('%:z')
+    sign = if offset < 0 then '-' else '+' end
+    fr = offset.abs
+    ss = fr.div(SECONDS_IN_DAY)
+    hh, ss = ss.divmod(3600)
+    mm     = ss.div(60)
+    format('%s%02d:%02d', sign, hh, mm)
+  end
+
+  private :zone_r
+
+  # Get the commercial year of this date.  See *Commercial* *Date*
+  # in the introduction for how this differs from the normal year.
+  def cwyear_r() commercial[0] end # :nodoc:
+
+  # Get the commercial week of the year of this date.
+  def cweek_r() commercial[1] end # :nodoc:
+
+  # Get the commercial day of the week of this date.  Monday is
+  # commercial day-of-week 1; Sunday is commercial day-of-week 7.
+  def cwday_r() commercial[2] end # :nodoc:
+
+  private :cwyear_r, :cweek_r, :cwday_r
+
+  # Get the week day of this date.  Sunday is day-of-week 0;
+  # Saturday is day-of-week 6.
+  def wday_r() jd_to_wday(jd) end # :nodoc:
+
+  once :wday_r
+  private :wday_r
+
+=begin
+  MONTHNAMES.each_with_index do |n, i|
+    if n
+      define_method(n.downcase + '?'){mon == i}
+    end
+  end
+=end
+
+  DAYNAMES.each_with_index do |n, i|
+    define_method(n.downcase + '?'){wday == i}
+  end
+
+  def nth_kday? (n, k) # :nodoc:
+    k == wday && jd === nth_kday_to_jd(year, mon, n, k, start)
+  end
+
+  private :nth_kday?
+
+  # Is the current date old-style (Julian Calendar)?
+  def julian_r? () jd < start end # :nodoc:
+
+  # Is the current date new-style (Gregorian Calendar)?
+  def gregorian_r? () !julian? end # :nodoc:
+
+  once :julian_r?, :gregorian_r?
+  private :julian_r?, :gregorian_r?
+
+  def fix_style # :nodoc:
+    if julian?
+    then self.class::JULIAN
+    else self.class::GREGORIAN end
+  end
+
+  private :fix_style
+
+  # Is this a leap year?
+  def leap_r? # :nodoc:
+    jd_to_civil(civil_to_jd(year, 3, 1, fix_style) - 1,
+		fix_style)[-1] == 29
+  end
+
+  once :leap_r?
+  private :leap_r?
+
+  # When is the Day of Calendar Reform for this Date object?
+  def start_r() @sg end # :nodoc:
+
+  # Create a copy of this Date object using a new Day of Calendar Reform.
+  def new_start_r(sg=self.class::ITALY) self.class.new_r!(ajd, offset, sg) end # :nodoc:
+
+  private :start_r, :new_start_r
+
+  # Create a copy of this Date object that uses the Italian/Catholic
+  # Day of Calendar Reform.
+  def italy() new_start(self.class::ITALY) end
+
+  # Create a copy of this Date object that uses the English/Colonial
+  # Day of Calendar Reform.
+  def england() new_start(self.class::ENGLAND) end
+
+  # Create a copy of this Date object that always uses the Julian
+  # Calendar.
+  def julian() new_start(self.class::JULIAN) end
+
+  # Create a copy of this Date object that always uses the Gregorian
+  # Calendar.
+  def gregorian() new_start(self.class::GREGORIAN) end
+
+  def new_offset_r(of=0) # :nodoc:
+    if String === of
+      of = Rational(zone_to_diff(of) || 0, 86400)
+    elsif Float === of
+      of = Rational((of * 86400).round, 86400)
+    end
+    self.class.new_r!(ajd, of, start)
+  end
+
+  private :new_offset_r
+
+  # Return a new Date object that is +n+ days later than the
+  # current one.
+  #
+  # +n+ may be a negative value, in which case the new Date
+  # is earlier than the current one; however, #-() might be
+  # more intuitive.
+  #
+  # If +n+ is not a Numeric, a TypeError will be thrown.  In
+  # particular, two Dates cannot be added to each other.
+  def plus_r (n) # :nodoc:
+    case n
+    when Numeric
+      if Float === n
+	n = Rational((n * 86400000000000).round, 86400000000000)
+      end
+      return self.class.new_r!(ajd + n, offset, start)
+    end
+    raise TypeError, 'expected numeric'
+  end
+
+  private :plus_r
+
+  # If +x+ is a Numeric value, create a new Date object that is
+  # +x+ days earlier than the current one.
+  #
+  # If +x+ is a Date, return the number of days between the
+  # two dates; or, more precisely, how many days later the current
+  # date is than +x+.
+  #
+  # If +x+ is neither Numeric nor a Date, a TypeError is raised.
+  def minus_r (x) # :nodoc:
+    case x
+    when Numeric
+      if Float === x
+	x = Rational((x * 86400000000000).round, 86400000000000)
+      end
+      return self.class.new_r!(ajd - x, offset, start)
+    when Date
+      return ajd - x.ajd
+    end
+    raise TypeError, 'expected numeric or date'
+  end
+
+  private :minus_r
+
+  # Compare this date with another date.
+  #
+  # +other+ can also be a Numeric value, in which case it is
+  # interpreted as an Astronomical Julian Day Number.
+  #
+  # Comparison is by Astronomical Julian Day Number, including
+  # fractional days.  This means that both the time and the
+  # offset are taken into account when comparing
+  # two DateTime instances.  When comparing a DateTime instance
+  # with a Date instance, the time of the latter will be
+  # considered as falling on midnight UTC.
+  def cmp_r (other) # :nodoc:
+    case other
+    when Numeric; return ajd <=> other
+    when Date;    return ajd <=> other.ajd
+    else
+      begin
+        l, r = other.coerce(self)
+        return l <=> r
+      rescue NoMethodError
+      end
+    end
+    nil
+  end
+
+  private :cmp_r
+
+  # The relationship operator for Date.
+  #
+  # Compares dates by Julian Day Number.  When comparing
+  # two DateTime instances, or a DateTime with a Date,
+  # the instances will be regarded as equivalent if they
+  # fall on the same date in local time.
+  def equal_r (other) # :nodoc:
+    case other
+    when Numeric; return jd == other
+    when Date;    return jd == other.jd
+    else
+      begin
+	l, r = other.coerce(self)
+	return l === r
+      rescue NoMethodError
+      end
+    end
+    false
+  end
+
+  private :equal_r
+
+  def next_day(n=1) self + n end
+  def prev_day(n=1) self - n end
+
+  # Return a new Date one day after this one.
+  def next() next_day end
+
+  alias_method :succ, :next
+
+  # Return a new Date object that is +n+ months later than
+  # the current one.
+  #
+  # If the day-of-the-month of the current Date is greater
+  # than the last day of the target month, the day-of-the-month
+  # of the returned Date will be the last day of the target month.
+  def >> (n)
+    y, m = (year * 12 + (mon - 1) + n).divmod(12)
+    m,   = (m + 1)                    .divmod(1)
+    d = mday
+    until jd2 = _valid_civil?(y, m, d, start)
+      d -= 1
+      raise ArgumentError, 'invalid date' unless d > 0
+    end
+    self + (jd2 - jd)
+  end
+
+  # Return a new Date object that is +n+ months earlier than
+  # the current one.
+  #
+  # If the day-of-the-month of the current Date is greater
+  # than the last day of the target month, the day-of-the-month
+  # of the returned Date will be the last day of the target month.
+  def << (n) self >> -n end
+
+  def next_month(n=1) self >> n end
+  def prev_month(n=1) self << n end
+
+  def next_year(n=1) self >> n * 12 end
+  def prev_year(n=1) self << n * 12 end
+
+  require 'enumerator'
+
+  # Step the current date forward +step+ days at a
+  # time (or backward, if +step+ is negative) until
+  # we reach +limit+ (inclusive), yielding the resultant
+  # date at each step.
+  def step(limit, step=1) # :yield: date
+=begin
+    if step.zero?
+      raise ArgumentError, "step can't be 0"
+    end
+=end
+    unless block_given?
+      return to_enum(:step, limit, step)
+    end
+    da = self
+    op = %w(- <= >=)[step <=> 0]
+    while da.__send__(op, limit)
+      yield da
+      da += step
+    end
+    self
+  end
+
+  # Step forward one day at a time until we reach +max+
+  # (inclusive), yielding each date as we go.
+  def upto(max, &block) # :yield: date
+    step(max, +1, &block)
+  end
+
+  # Step backward one day at a time until we reach +min+
+  # (inclusive), yielding each date as we go.
+  def downto(min, &block) # :yield: date
+    step(min, -1, &block)
+  end
+
+  # Is this Date equal to +other+?
+  #
+  # +other+ must both be a Date object, and represent the same date.
+  def eql_r? (other) Date === other && self == other end # :nodoc:
+
+  private :eql_r?
+
+  # Calculate a hash value for this date.
+  def hash_r() ajd.hash end # :nodoc:
+
+  private :hash_r
+
+  # Return internal object state as a programmer-readable string.
+  def inspect_r # :nodoc:
+    format('#<%s[R]: %s (%s,%s,%s)>', self.class, to_s_r, ajd, offset, start)
+  end
+
+  private :inspect_r
+
+  # Return the date as a human-readable string.
+  #
+  # The format used is YYYY-MM-DD.
+  def to_s_r() format('%.4d-%02d-%02d', year, mon, mday) end # :nodoc: # 4p
+
+  private :to_s_r
+
+end
+
+# Class representing a date and time.
+#
+# See the documentation to the file date.rb for an overview.
+#
+# DateTime objects are immutable once created.
+#
+# == Other methods.
+#
+# The following methods are defined in Date, but declared private
+# there.  They are made public in DateTime.  They are documented
+# here.
+#
+# === hour()
+#
+# Get the hour-of-the-day of the time.  This is given
+# using the 24-hour clock, counting from midnight.  The first
+# hour after midnight is hour 0; the last hour of the day is
+# hour 23.
+#
+# === min()
+#
+# Get the minute-of-the-hour of the time.
+#
+# === sec()
+#
+# Get the second-of-the-minute of the time.
+#
+# === sec_fraction()
+#
+# Get the fraction of a second of the time.  This is returned as
+# a +Rational+.
+#
+# === zone()
+#
+# Get the time zone as a String.  This is representation of the
+# time offset such as "+10:00".
+#
+# === offset()
+#
+# Get the time zone offset as a fraction of a day.  This is returned
+# as a +Rational+.
+#
+# === new_offset(of=0)
+#
+# Create a new DateTime object, identical to the current one, except
+# with a new time zone offset of +of+.  +of+ is the new offset from
+# UTC as a fraction of a day.
+#
+class DateTime < Date
+
+  def self.new!(ajd=0, of=0, sg=ITALY)
+    jd, df = ajd_to_jd(ajd, 0)
+    df, sf = (df * 86400).divmod(1)
+    sf, ssf = (sf * 1000000000).divmod(1)
+    odf, osf = (of * 86400).divmod(1)
+    if !(Fixnum === jd) ||
+	jd < sg || ssf != 0 || osf != 0 ||
+        jd < -327 || jd > 366963925
+      return new_r!(ajd, of, sg)
+    end
+    new_l!(jd, df, sf, odf, sg)
+  end
+
+  # Create a new DateTime object corresponding to the specified
+  # Julian Day Number +jd+ and hour +h+, minute +min+, second +s+.
+  #
+  # The 24-hour clock is used.  Negative values of +h+, +min+, and
+  # +sec+ are treating as counting backwards from the end of the
+  # next larger unit (e.g. a +min+ of -2 is treated as 58).  No
+  # wraparound is performed.  If an invalid time portion is specified,
+  # an ArgumentError is raised.
+  #
+  # +of+ is the offset from UTC as a fraction of a day (defaults to 0).
+  # +sg+ specifies the Day of Calendar Reform.
+  #
+  # All day/time values default to 0.
+  def self.jd_r(jd=0, h=0, min=0, s=0, of=0, sg=ITALY) # :nodoc:
+    unless (jd = _valid_jd?(jd, sg)) &&
+	   (fr = _valid_time?(h, min, s))
+      raise ArgumentError, 'invalid date'
+    end
+    if String === of
+      of = Rational(zone_to_diff(of) || 0, 86400)
+    elsif Float === of
+      of = Rational((of * 86400).round, 86400)
+    end
+    new_r!(jd_to_ajd(jd, fr, of), of, sg)
+  end
+
+  private_class_method :jd_r
+
+  # Create a new DateTime object corresponding to the specified
+  # Ordinal Date and hour +h+, minute +min+, second +s+.
+  #
+  # The 24-hour clock is used.  Negative values of +h+, +min+, and
+  # +sec+ are treating as counting backwards from the end of the
+  # next larger unit (e.g. a +min+ of -2 is treated as 58).  No
+  # wraparound is performed.  If an invalid time portion is specified,
+  # an ArgumentError is raised.
+  #
+  # +of+ is the offset from UTC as a fraction of a day (defaults to 0).
+  # +sg+ specifies the Day of Calendar Reform.
+  #
+  # +y+ defaults to -4712, and +d+ to 1; this is Julian Day Number
+  # day 0.  The time values default to 0.
+  def self.ordinal_r(y=-4712, d=1, h=0, min=0, s=0, of=0, sg=ITALY) # :nodoc:
+    unless (jd = _valid_ordinal?(y, d, sg)) &&
+	   (fr = _valid_time?(h, min, s))
+      raise ArgumentError, 'invalid date'
+    end
+    if String === of
+      of = Rational(zone_to_diff(of) || 0, 86400)
+    elsif Float === of
+      of = Rational((of * 86400).round, 86400)
+    end
+    new_r!(jd_to_ajd(jd, fr, of), of, sg)
+  end
+
+  private_class_method :ordinal_r
+
+  # Create a new DateTime object corresponding to the specified
+  # Civil Date and hour +h+, minute +min+, second +s+.
+  #
+  # The 24-hour clock is used.  Negative values of +h+, +min+, and
+  # +sec+ are treating as counting backwards from the end of the
+  # next larger unit (e.g. a +min+ of -2 is treated as 58).  No
+  # wraparound is performed.  If an invalid time portion is specified,
+  # an ArgumentError is raised.
+  #
+  # +of+ is the offset from UTC as a fraction of a day (defaults to 0).
+  # +sg+ specifies the Day of Calendar Reform.
+  #
+  # +y+ defaults to -4712, +m+ to 1, and +d+ to 1; this is Julian Day
+  # Number day 0.  The time values default to 0.
+  def self.civil_r(y=-4712, m=1, d=1, h=0, min=0, s=0, of=0, sg=ITALY) # :nodoc:
+    unless (jd = _valid_civil?(y, m, d, sg)) &&
+	   (fr = _valid_time?(h, min, s))
+      raise ArgumentError, 'invalid date'
+    end
+    if String === of
+      of = Rational(zone_to_diff(of) || 0, 86400)
+    elsif Float === of
+      of = Rational((of * 86400).round, 86400)
+    end
+    new_r!(jd_to_ajd(jd, fr, of), of, sg)
+  end
+
+  private_class_method :civil_r
+
+  # Create a new DateTime object corresponding to the specified
+  # Commercial Date and hour +h+, minute +min+, second +s+.
+  #
+  # The 24-hour clock is used.  Negative values of +h+, +min+, and
+  # +sec+ are treating as counting backwards from the end of the
+  # next larger unit (e.g. a +min+ of -2 is treated as 58).  No
+  # wraparound is performed.  If an invalid time portion is specified,
+  # an ArgumentError is raised.
+  #
+  # +of+ is the offset from UTC as a fraction of a day (defaults to 0).
+  # +sg+ specifies the Day of Calendar Reform.
+  #
+  # +y+ defaults to -4712, +w+ to 1, and +d+ to 1; this is
+  # Julian Day Number day 0.
+  # The time values default to 0.
+  def self.commercial_r(y=-4712, w=1, d=1, h=0, min=0, s=0, of=0, sg=ITALY) # :nodoc:
+    unless (jd = _valid_commercial?(y, w, d, sg)) &&
+	   (fr = _valid_time?(h, min, s))
+      raise ArgumentError, 'invalid date'
+    end
+    if String === of
+      of = Rational(zone_to_diff(of) || 0, 86400)
+    elsif Float === of
+      of = Rational((of * 86400).round, 86400)
+    end
+    new_r!(jd_to_ajd(jd, fr, of), of, sg)
+  end
+
+  private_class_method :commercial_r
+
+  def self.weeknum(y=-4712, w=0, d=1, f=0, h=0, min=0, s=0, of=0, sg=ITALY) # :nodoc:
+    unless (jd = _valid_weeknum?(y, w, d, f, sg)) &&
+	   (fr = _valid_time?(h, min, s))
+      raise ArgumentError, 'invalid date'
+    end
+    if String === of
+      of = Rational(zone_to_diff(of) || 0, 86400)
+    elsif Float === of
+      of = Rational((of * 86400).round, 86400)
+    end
+    new!(jd_to_ajd(jd, fr, of), of, sg)
+  end
+
+  private_class_method :weeknum
+
+  def self.nth_kday(y=-4712, m=1, n=1, k=1, h=0, min=0, s=0, of=0, sg=ITALY) # :nodoc:
+    unless (jd = _valid_nth_kday?(y, m, n, k, sg)) &&
+	   (fr = _valid_time?(h, min, s))
+      raise ArgumentError, 'invalid date'
+    end
+    if String === of
+      of = Rational(zone_to_diff(of) || 0, 86400)
+    elsif Float === of
+      of = Rational((of * 86400).round, 86400)
+    end
+    new!(jd_to_ajd(jd, fr, of), of, sg)
+  end
+
+  private_class_method :nth_kday
+
+  def self.new_by_frags(elem, sg) # :nodoc:
+    elem = rewrite_frags(elem)
+    elem = complete_frags(elem)
+    unless (jd = valid_date_frags?(elem, sg)) &&
+	   (fr = valid_time_frags?(elem))
+      raise ArgumentError, 'invalid date'
+    end
+    fr += (elem[:sec_fraction] || 0) / 86400
+    of = Rational(elem[:offset] || 0, 86400)
+    new!(jd_to_ajd(jd, fr, of), of, sg)
+  end
+
+  private_class_method :new_by_frags
+
+  # Create a new DateTime object by parsing from a String
+  # according to a specified format.
+  #
+  # +str+ is a String holding a date-time representation.
+  # +fmt+ is the format that the date-time is in.  See
+  # date/format.rb for details on supported formats.
+  #
+  # The default +str+ is '-4712-01-01T00:00:00+00:00', and the default
+  # +fmt+ is '%FT%T%z'.  This gives midnight on Julian Day Number day 0.
+  #
+  # +sg+ specifies the Day of Calendar Reform.
+  #
+  # An ArgumentError will be raised if +str+ cannot be
+  # parsed.
+  def self.strptime(str='-4712-01-01T00:00:00+00:00', fmt='%FT%T%z', sg=ITALY)
+    elem = _strptime(str, fmt)
+    new_by_frags(elem, sg)
+  end
+
+  # Create a new DateTime object by parsing from a String,
+  # without specifying the format.
+  #
+  # +str+ is a String holding a date-time representation.
+  # +comp+ specifies whether to interpret 2-digit years
+  # as 19XX (>= 69) or 20XX (< 69); the default is to.
+  # The method will attempt to parse a date-time from the String
+  # using various heuristics; see #_parse in date/format.rb
+  # for more details.  If parsing fails, an ArgumentError
+  # will be raised.
+  #
+  # The default +str+ is '-4712-01-01T00:00:00+00:00'; this is Julian
+  # Day Number day 0.
+  #
+  # +sg+ specifies the Day of Calendar Reform.
+  def self.parse(str='-4712-01-01T00:00:00+00:00', comp=true, sg=ITALY)
+    elem = _parse(str, comp)
+    new_by_frags(elem, sg)
+  end
+
+  def self.iso8601(str='-4712-01-01T00:00:00+00:00', sg=ITALY) # :nodoc:
+    elem = _iso8601(str)
+    new_by_frags(elem, sg)
+  end
+
+  def self.xmlschema(str='-4712-01-01T00:00:00+00:00', sg=ITALY) # :nodoc:
+    elem = _xmlschema(str)
+    new_by_frags(elem, sg)
+  end
+
+  def self.rfc2822(str='Mon, 1 Jan -4712 00:00:00 +0000', sg=ITALY) # :nodoc:
+    elem = _rfc2822(str)
+    new_by_frags(elem, sg)
+  end
+
+  class << self; alias_method :rfc822, :rfc2822 end
+
+  def self.httpdate(str='Mon, 01 Jan -4712 00:00:00 GMT', sg=ITALY) # :nodoc:
+    elem = _httpdate(str)
+    new_by_frags(elem, sg)
+  end
+
+  def self.jisx0301(str='-4712-01-01T00:00:00+00:00', sg=ITALY) # :nodoc:
+    elem = _jisx0301(str)
+    new_by_frags(elem, sg)
+  end
+
+  def to_s_r # :nodoc: # 4p
+    format('%.4d-%02d-%02dT%02d:%02d:%02d%s',
+	   year, mon, mday, hour, min, sec, zone)
+  end
+
+  private :to_s_r
+
+end
+
+class Time
+
+  def to_time() getlocal end
+
+  def to_date
+    jd = Date.__send__(:civil_to_jd, year, mon, mday, Date::ITALY)
+    Date.new!(Date.__send__(:jd_to_ajd, jd, 0, 0), 0, Date::ITALY)
+  end
+
+  def to_datetime
+    jd = DateTime.__send__(:civil_to_jd, year, mon, mday, DateTime::ITALY)
+    fr = DateTime.__send__(:time_to_day_fraction, hour, min, [sec, 59].min) +
+      Rational(subsec, 86400)
+    of = Rational(utc_offset, 86400)
+    DateTime.new!(DateTime.__send__(:jd_to_ajd, jd, fr, of),
+                  of, DateTime::ITALY)
+  end
+
+end
+
+class Date
+
+  def to_time() Time.local(year, mon, mday) end
+  def to_date() self end
+  def to_datetime() DateTime.new!(jd_to_ajd(jd, 0, 0), offset, start) end
+
+end
+
+class DateTime < Date
+
+  def to_time
+    d = new_offset(0)
+    d.instance_eval do
+      Time.utc(year, mon, mday, hour, min, sec +
+	       sec_fraction)
+    end.
+        getlocal
+  end
+
+  def to_date() Date.new!(jd_to_ajd(jd, 0, 0), 0, start) end
+  def to_datetime() self end
+
+end
+
+require 'date_core'
diff --git a/ext/date/lib/date/format.rb b/ext/date/lib/date/format.rb
new file mode 100644
index 0000000000..6894e945e3
--- /dev/null
+++ b/ext/date/lib/date/format.rb
@@ -0,0 +1,1311 @@
+# format.rb: Written by Tadayoshi Funaba 1999-2010
+# $Id: format.rb,v 2.43 2008-01-17 20:16:31+09 tadf Exp $
+
+class Date
+
+  module Format # :nodoc:
+
+    MONTHS = {
+      'january'  => 1, 'february' => 2, 'march'    => 3, 'april'    => 4,
+      'may'      => 5, 'june'     => 6, 'july'     => 7, 'august'   => 8,
+      'september'=> 9, 'october'  =>10, 'november' =>11, 'december' =>12
+    }
+
+    DAYS = {
+      'sunday'   => 0, 'monday'   => 1, 'tuesday'  => 2, 'wednesday'=> 3,
+      'thursday' => 4, 'friday'   => 5, 'saturday' => 6
+    }
+
+    ABBR_MONTHS = {
+      'jan'      => 1, 'feb'      => 2, 'mar'      => 3, 'apr'      => 4,
+      'may'      => 5, 'jun'      => 6, 'jul'      => 7, 'aug'      => 8,
+      'sep'      => 9, 'oct'      =>10, 'nov'      =>11, 'dec'      =>12
+    }
+
+    ABBR_DAYS = {
+      'sun'      => 0, 'mon'      => 1, 'tue'      => 2, 'wed'      => 3,
+      'thu'      => 4, 'fri'      => 5, 'sat'      => 6
+    }
+
+    ZONES = {
+      'ut'  =>  0*3600, 'gmt' =>  0*3600, 'est' => -5*3600, 'edt' => -4*3600,
+      'cst' => -6*3600, 'cdt' => -5*3600, 'mst' => -7*3600, 'mdt' => -6*3600,
+      'pst' => -8*3600, 'pdt' => -7*3600,
+      'a'   =>  1*3600, 'b'   =>  2*3600, 'c'   =>  3*3600, 'd'   =>  4*3600,
+      'e'   =>  5*3600, 'f'   =>  6*3600, 'g'   =>  7*3600, 'h'   =>  8*3600,
+      'i'   =>  9*3600, 'k'   => 10*3600, 'l'   => 11*3600, 'm'   => 12*3600,
+      'n'   => -1*3600, 'o'   => -2*3600, 'p'   => -3*3600, 'q'   => -4*3600,
+      'r'   => -5*3600, 's'   => -6*3600, 't'   => -7*3600, 'u'   => -8*3600,
+      'v'   => -9*3600, 'w'   =>-10*3600, 'x'   =>-11*3600, 'y'   =>-12*3600,
+      'z'   =>  0*3600,
+
+      'utc' =>  0*3600, 'wet' =>  0*3600,
+      'at'  => -2*3600, 'brst'=> -2*3600, 'ndt' => -(2*3600+1800),
+      'art' => -3*3600, 'adt' => -3*3600, 'brt' => -3*3600, 'clst'=> -3*3600,
+      'nst' => -(3*3600+1800),
+      'ast' => -4*3600, 'clt' => -4*3600,
+      'akdt'=> -8*3600, 'ydt' => -8*3600,
+      'akst'=> -9*3600, 'hadt'=> -9*3600, 'hdt' => -9*3600, 'yst' => -9*3600,
+      'ahst'=>-10*3600, 'cat' =>-10*3600, 'hast'=>-10*3600, 'hst' =>-10*3600,
+      'nt'  =>-11*3600,
+      'idlw'=>-12*3600,
+      'bst' =>  1*3600, 'cet' =>  1*3600, 'fwt' =>  1*3600, 'met' =>  1*3600,
+      'mewt'=>  1*3600, 'mez' =>  1*3600, 'swt' =>  1*3600, 'wat' =>  1*3600,
+      'west'=>  1*3600,
+      'cest'=>  2*3600, 'eet' =>  2*3600, 'fst' =>  2*3600, 'mest'=>  2*3600,
+      'mesz'=>  2*3600, 'sast'=>  2*3600, 'sst' =>  2*3600,
+      'bt'  =>  3*3600, 'eat' =>  3*3600, 'eest'=>  3*3600, 'msk' =>  3*3600,
+      'msd' =>  4*3600, 'zp4' =>  4*3600,
+      'zp5' =>  5*3600, 'ist' =>  (5*3600+1800),
+      'zp6' =>  6*3600,
+      'wast'=>  7*3600,
+      'cct' =>  8*3600, 'sgt' =>  8*3600, 'wadt'=>  8*3600,
+      'jst' =>  9*3600, 'kst' =>  9*3600,
+      'east'=> 10*3600, 'gst' => 10*3600,
+      'eadt'=> 11*3600,
+      'idle'=> 12*3600, 'nzst'=> 12*3600, 'nzt' => 12*3600,
+      'nzdt'=> 13*3600,
+
+      'afghanistan'           =>   16200, 'alaskan'               =>  -32400,
+      'arab'                  =>   10800, 'arabian'               =>   14400,
+      'arabic'                =>   10800, 'atlantic'              =>  -14400,
+      'aus central'           =>   34200, 'aus eastern'           =>   36000,
+      'azores'                =>   -3600, 'canada central'        =>  -21600,
+      'cape verde'            =>   -3600, 'caucasus'              =>   14400,
+      'cen. australia'        =>   34200, 'central america'       =>  -21600,
+      'central asia'          =>   21600, 'central europe'        =>    3600,
+      'central european'      =>    3600, 'central pacific'       =>   39600,
+      'central'               =>  -21600, 'china'                 =>   28800,
+      'dateline'              =>  -43200, 'e. africa'             =>   10800,
+      'e. australia'          =>   36000, 'e. europe'             =>    7200,
+      'e. south america'      =>  -10800, 'eastern'               =>  -18000,
+      'egypt'                 =>    7200, 'ekaterinburg'          =>   18000,
+      'fiji'                  =>   43200, 'fle'                   =>    7200,
+      'greenland'             =>  -10800, 'greenwich'             =>       0,
+      'gtb'                   =>    7200, 'hawaiian'              =>  -36000,
+      'india'                 =>   19800, 'iran'                  =>   12600,
+      'jerusalem'             =>    7200, 'korea'                 =>   32400,
+      'mexico'                =>  -21600, 'mid-atlantic'          =>   -7200,
+      'mountain'              =>  -25200, 'myanmar'               =>   23400,
+      'n. central asia'       =>   21600, 'nepal'                 =>   20700,
+      'new zealand'           =>   43200, 'newfoundland'          =>  -12600,
+      'north asia east'       =>   28800, 'north asia'            =>   25200,
+      'pacific sa'            =>  -14400, 'pacific'               =>  -28800,
+      'romance'               =>    3600, 'russian'               =>   10800,
+      'sa eastern'            =>  -10800, 'sa pacific'            =>  -18000,
+      'sa western'            =>  -14400, 'samoa'                 =>  -39600,
+      'se asia'               =>   25200, 'malay peninsula'       =>   28800,
+      'south africa'          =>    7200, 'sri lanka'             =>   21600,
+      'taipei'                =>   28800, 'tasmania'              =>   36000,
+      'tokyo'                 =>   32400, 'tonga'                 =>   46800,
+      'us eastern'            =>  -18000, 'us mountain'           =>  -25200,
+      'vladivostok'           =>   36000, 'w. australia'          =>   28800,
+      'w. central africa'     =>    3600, 'w. europe'             =>    3600,
+      'west asia'             =>   18000, 'west pacific'          =>   36000,
+      'yakutsk'               =>   32400
+    }
+
+    [MONTHS, DAYS, ABBR_MONTHS, ABBR_DAYS, ZONES].each do |x|
+      x.freeze
+    end
+
+    class BagStruct < Struct # :nodoc:
+
+      def to_hash
+	h = {}
+	members.each do |k|
+	  unless /\A_/ =~ k.to_s || self[k].nil?
+	    h[k] = self[k]
+	  end
+	end
+	h
+      end
+
+    end
+
+    Bag = BagStruct.new(:year, :mon, :yday, :mday, :wday,
+			:cwyear, :cweek, :cwday,
+			:hour, :min, :sec, :sec_fraction,
+			:wnum0, :wnum1, :seconds,
+			:zone, :offset, :leftover,
+			:_cent, :_merid, :_comp)
+
+  end
+
+  def emit(e, f) # :nodoc:
+    case e
+    when Numeric
+      sign = %w(+ + -)[e <=> 0]
+      e = e.abs
+    end
+
+    s = e.to_s
+
+    if f[:s] && f[:p] == '0'
+      f[:w] -= 1
+    end
+
+    if f[:s] && f[:p] == "\s"
+      s[0,0] = sign
+    end
+
+    if f[:p] != '-'
+      s = s.rjust(f[:w], f[:p])
+    end
+
+    if f[:s] && f[:p] != "\s"
+      s[0,0] = sign
+    end
+
+    s = s.upcase if f[:u]
+    s = s.downcase if f[:d]
+    s
+  end
+
+  def emit_w(e, w, f) # :nodoc:
+    f[:w] = [f[:w], w].compact.max
+    emit(e, f)
+  end
+
+  def emit_n(e, w, f) # :nodoc:
+    f[:p] ||= '0'
+    emit_w(e, w, f)
+  end
+
+  def emit_sn(e, w, f) # :nodoc:
+    if e < 0
+      w += 1
+      f[:s] = true
+    end
+    emit_n(e, w, f)
+  end
+
+  def emit_z(e, w, f) # :nodoc:
+    w += 1
+    f[:s] = true
+    emit_n(e, w, f)
+  end
+
+  def emit_a(e, w, f) # :nodoc:
+    f[:p] ||= "\s"
+    emit_w(e, w, f)
+  end
+
+  def emit_ad(e, w, f) # :nodoc:
+    if f[:x]
+      f[:u] = true
+      f[:d] = false
+    end
+    emit_a(e, w, f)
+  end
+
+  def emit_au(e, w, f) # :nodoc:
+    if f[:x]
+      f[:u] = false
+      f[:d] = true
+    end
+    emit_a(e, w, f)
+  end
+
+  private :emit, :emit_w, :emit_n, :emit_sn, :emit_z,
+	  :emit_a, :emit_ad, :emit_au
+
+  def strftime(fmt='%F')
+    fmt.gsub(/%([-_0^#]+)?(\d+)?([EO]?(?::{1,3}z|.))/m) do
+      f = {}
+      m = $&
+      s, w, c = $1, $2, $3
+      if s
+	s.scan(/./) do |k|
+	  case k
+	  when '-'; f[:p] = '-'
+	  when '_'; f[:p] = "\s"
+	  when '0'; f[:p] = '0'
+	  when '^'; f[:u] = true
+	  when '#'; f[:x] = true
+	  end
+	end
+      end
+      if w
+	f[:w] = w.to_i
+      end
+      case c
+      when 'A'; emit_ad(DAYNAMES[wday], 0, f)
+      when 'a'; emit_ad(ABBR_DAYNAMES[wday], 0, f)
+      when 'B'; emit_ad(MONTHNAMES[mon], 0, f)
+      when 'b'; emit_ad(ABBR_MONTHNAMES[mon], 0, f)
+      when 'C', 'EC'; emit_sn((year / 100).floor, 2, f)
+      when 'c', 'Ec'; emit_a(strftime('%a %b %e %H:%M:%S %Y'), 0, f)
+      when 'D'; emit_a(strftime('%m/%d/%y'), 0, f)
+      when 'd', 'Od'; emit_n(mday, 2, f)
+      when 'e', 'Oe'; emit_a(mday, 2, f)
+      when 'F'
+	if m == '%F'
+	  format('%.4d-%02d-%02d', year, mon, mday) # 4p
+	else
+	  emit_a(strftime('%Y-%m-%d'), 0, f)
+	end
+      when 'G'; emit_sn(cwyear, 4, f)
+      when 'g'; emit_n(cwyear % 100, 2, f)
+      when 'H', 'OH'; emit_n(hour, 2, f)
+      when 'h'; emit_ad(strftime('%b'), 0, f)
+      when 'I', 'OI'; emit_n((hour % 12).nonzero? || 12, 2, f)
+      when 'j'; emit_n(yday, 3, f)
+      when 'k'; emit_a(hour, 2, f)
+      when 'L'
+	f[:p] = nil
+	w = f[:w] || 3
+	u = 10**w
+	emit_n((sec_fraction * u).floor, w, f)
+      when 'l'; emit_a((hour % 12).nonzero? || 12, 2, f)
+      when 'M', 'OM'; emit_n(min, 2, f)
+      when 'm', 'Om'; emit_n(mon, 2, f)
+      when 'N'
+	f[:p] = nil
+	w = f[:w] || 9
+	u = 10**w
+	emit_n((sec_fraction * u).floor, w, f)
+      when 'n'; emit_a("\n", 0, f)
+      when 'P'; emit_ad(strftime('%p').downcase, 0, f)
+      when 'p'; emit_au(if hour < 12 then 'AM' else 'PM' end, 0, f)
+      when 'Q'
+	s = ((ajd - UNIX_EPOCH_IN_AJD) / MILLISECONDS_IN_DAY).round
+	emit_sn(s, 1, f)
+      when 'R'; emit_a(strftime('%H:%M'), 0, f)
+      when 'r'; emit_a(strftime('%I:%M:%S %p'), 0, f)
+      when 'S', 'OS'; emit_n(sec, 2, f)
+      when 's'
+	s = ((ajd - UNIX_EPOCH_IN_AJD) / SECONDS_IN_DAY).round
+	emit_sn(s, 1, f)
+      when 'T'
+	if m == '%T'
+	  format('%02d:%02d:%02d', hour, min, sec) # 4p
+	else
+	  emit_a(strftime('%H:%M:%S'), 0, f)
+	end
+      when 't'; emit_a("\t", 0, f)
+      when 'U', 'W', 'OU', 'OW'
+	emit_n(if c[-1,1] == 'U' then wnum0 else wnum1 end, 2, f)
+      when 'u', 'Ou'; emit_n(cwday, 1, f)
+      when 'V', 'OV'; emit_n(cweek, 2, f)
+      when 'v'; emit_a(strftime('%e-%b-%Y'), 0, f)
+      when 'w', 'Ow'; emit_n(wday, 1, f)
+      when 'X', 'EX'; emit_a(strftime('%H:%M:%S'), 0, f)
+      when 'x', 'Ex'; emit_a(strftime('%m/%d/%y'), 0, f)
+      when 'Y', 'EY'; emit_sn(year, 4, f)
+      when 'y', 'Ey', 'Oy'; emit_n(year % 100, 2, f)
+      when 'Z'; emit_au(strftime('%:z'), 0, f)
+      when /\A(:{0,3})z/
+	t = $1.size
+	sign = if offset < 0 then -1 else +1 end
+	fr = offset.abs
+	ss = fr.div(SECONDS_IN_DAY) # 4p
+	hh, ss = ss.divmod(3600)
+	mm, ss = ss.divmod(60)
+	if t == 3
+	  if    ss.nonzero? then t =  2
+	  elsif mm.nonzero? then t =  1
+	  else                   t = -1
+	  end
+	end
+	case t
+	when -1
+	  tail = []
+	  sep = ''
+	when 0
+	  f[:w] -= 2 if f[:w]
+	  tail = ['%02d' % mm]
+	  sep = ''
+	when 1
+	  f[:w] -= 3 if f[:w]
+	  tail = ['%02d' % mm]
+	  sep = ':'
+	when 2
+	  f[:w] -= 6 if f[:w]
+	  tail = ['%02d' % mm, '%02d' % ss]
+	  sep = ':'
+	end
+	([emit_z(sign * hh, 2, f)] + tail).join(sep)
+      when '%'; emit_a('%', 0, f)
+      when '+'; emit_a(strftime('%a %b %e %H:%M:%S %Z %Y'), 0, f)
+      else
+	m
+      end
+    end
+  end
+
+# alias_method :format, :strftime
+
+  def asctime() strftime('%c') end
+
+  alias_method :ctime, :asctime
+
+  def iso8601() strftime('%F') end
+
+  def rfc3339() strftime('%FT%T%:z') end
+
+  def xmlschema() iso8601 end # :nodoc:
+
+  def rfc2822() strftime('%a, %-d %b %Y %T %z') end
+
+  alias_method :rfc822, :rfc2822
+
+  def httpdate() new_offset(0).strftime('%a, %d %b %Y %T GMT') end # :nodoc:
+
+  def jisx0301
+    if jd < 2405160
+      strftime('%F')
+    else
+      case jd
+      when 2405160...2419614
+	g = 'M%02d' % (year - 1867)
+      when 2419614...2424875
+	g = 'T%02d' % (year - 1911)
+      when 2424875...2447535
+	g = 'S%02d' % (year - 1925)
+      else
+	g = 'H%02d' % (year - 1988)
+      end
+      g + strftime('.%m.%d')
+    end
+  end
+
+=begin
+  def beat(n=0)
+    i, f = (new_offset(HOURS_IN_DAY).day_fraction * 1000).divmod(1)
+    ('@%03d' % i) +
+      if n < 1
+	''
+      else
+	'.%0*d' % [n, (f / Rational(1, 10**n)).round]
+      end
+  end
+=end
+
+  def self.num_pattern? (s) # :nodoc:
+    /\A%[EO]?[CDdeFGgHIjkLlMmNQRrSsTUuVvWwXxYy\d]/ =~ s || /\A\d/ =~ s
+  end
+
+  private_class_method :num_pattern?
+
+  def self._strptime_i(str, fmt, e) # :nodoc:
+    fmt.scan(/%([EO]?(?::{1,3}z|.))|(.)/m) do |s, c|
+      a = $&
+      if s
+	case s
+	when 'A', 'a'
+	  return unless str.sub!(/\A(#{Format::DAYS.keys.join('|')})/io, '') ||
+			str.sub!(/\A(#{Format::ABBR_DAYS.keys.join('|')})/io, '')
+	  val = Format::DAYS[$1.downcase] || Format::ABBR_DAYS[$1.downcase]
+	  return unless val
+	  e.wday = val
+	when 'B', 'b', 'h'
+	  return unless str.sub!(/\A(#{Format::MONTHS.keys.join('|')})/io, '') ||
+			str.sub!(/\A(#{Format::ABBR_MONTHS.keys.join('|')})/io, '')
+	  val = Format::MONTHS[$1.downcase] || Format::ABBR_MONTHS[$1.downcase]
+	  return unless val
+	  e.mon = val
+	when 'C', 'EC'
+	  return unless str.sub!(if num_pattern?($')
+				 then /\A([-+]?\d{1,2})/
+				 else /\A([-+]?\d{1,})/
+				 end, '')
+	  val = $1.to_i
+	  e._cent = val
+	when 'c', 'Ec'
+	  return unless _strptime_i(str, '%a %b %e %H:%M:%S %Y', e)
+	when 'D'
+	  return unless _strptime_i(str, '%m/%d/%y', e)
+	when 'd', 'e', 'Od', 'Oe'
+	  return unless str.sub!(/\A( \d|\d{1,2})/, '')
+	  val = $1.to_i
+	  return unless (1..31) === val
+	  e.mday = val
+	when 'F'
+	  return unless _strptime_i(str, '%Y-%m-%d', e)
+	when 'G'
+	  return unless str.sub!(if num_pattern?($')
+				 then /\A([-+]?\d{1,4})/
+				 else /\A([-+]?\d{1,})/
+				 end, '')
+	  val = $1.to_i
+	  e.cwyear = val
+	when 'g'
+	  return unless str.sub!(/\A(\d{1,2})/, '')
+	  val = $1.to_i
+	  return unless (0..99) === val
+	  e.cwyear = val
+	  e._cent ||= if val >= 69 then 19 else 20 end
+	when 'H', 'k', 'OH'
+	  return unless str.sub!(/\A( \d|\d{1,2})/, '')
+	  val = $1.to_i
+	  return unless (0..24) === val
+	  e.hour = val
+	when 'I', 'l', 'OI'
+	  return unless str.sub!(/\A( \d|\d{1,2})/, '')
+	  val = $1.to_i
+	  return unless (1..12) === val
+	  e.hour = val
+	when 'j'
+	  return unless str.sub!(/\A(\d{1,3})/, '')
+	  val = $1.to_i
+	  return unless (1..366) === val
+	  e.yday = val
+	when 'L'
+	  return unless str.sub!(if num_pattern?($')
+				 then /\A([-+]?\d{1,3})/
+				 else /\A([-+]?\d{1,})/
+				 end, '')
+#	  val = Rational($1.to_i, 10**3)
+	  val = Rational($1.to_i, 10**$1.size)
+	  e.sec_fraction = val
+	when 'M', 'OM'
+	  return unless str.sub!(/\A(\d{1,2})/, '')
+	  val = $1.to_i
+	  return unless (0..59) === val
+	  e.min = val
+	when 'm', 'Om'
+	  return unless str.sub!(/\A(\d{1,2})/, '')
+	  val = $1.to_i
+	  return unless (1..12) === val
+	  e.mon = val
+	when 'N'
+	  return unless str.sub!(if num_pattern?($')
+				 then /\A([-+]?\d{1,9})/
+				 else /\A([-+]?\d{1,})/
+				 end, '')
+#	  val = Rational($1.to_i, 10**9)
+	  val = Rational($1.to_i, 10**$1.size)
+	  e.sec_fraction = val
+	when 'n', 't'
+	  return unless _strptime_i(str, "\s", e)
+	when 'P', 'p'
+	  return unless str.sub!(/\A([ap])(?:m\b|\.m\.)/i, '')
+	  e._merid = if $1.downcase == 'a' then 0 else 12 end
+	when 'Q'
+	  return unless str.sub!(/\A(-?\d{1,})/, '')
+	  val = Rational($1.to_i, 10**3)
+	  e.seconds = val
+	when 'R'
+	  return unless _strptime_i(str, '%H:%M', e)
+	when 'r'
+	  return unless _strptime_i(str, '%I:%M:%S %p', e)
+	when 'S', 'OS'
+	  return unless str.sub!(/\A(\d{1,2})/, '')
+	  val = $1.to_i
+	  return unless (0..60) === val
+	  e.sec = val
+	when 's'
+	  return unless str.sub!(/\A(-?\d{1,})/, '')
+	  val = $1.to_i
+	  e.seconds = val
+	when 'T'
+	  return unless _strptime_i(str, '%H:%M:%S', e)
+	when 'U', 'W', 'OU', 'OW'
+	  return unless str.sub!(/\A(\d{1,2})/, '')
+	  val = $1.to_i
+	  return unless (0..53) === val
+	  e.__send__(if s[-1,1] == 'U' then :wnum0= else :wnum1= end, val)
+	when 'u', 'Ou'
+	  return unless str.sub!(/\A(\d{1})/, '')
+	  val = $1.to_i
+	  return unless (1..7) === val
+	  e.cwday = val
+	when 'V', 'OV'
+	  return unless str.sub!(/\A(\d{1,2})/, '')
+	  val = $1.to_i
+	  return unless (1..53) === val
+	  e.cweek = val
+	when 'v'
+	  return unless _strptime_i(str, '%e-%b-%Y', e)
+	when 'w'
+	  return unless str.sub!(/\A(\d{1})/, '')
+	  val = $1.to_i
+	  return unless (0..6) === val
+	  e.wday = val
+	when 'X', 'EX'
+	  return unless _strptime_i(str, '%H:%M:%S', e)
+	when 'x', 'Ex'
+	  return unless _strptime_i(str, '%m/%d/%y', e)
+	when 'Y', 'EY'
+	  return unless str.sub!(if num_pattern?($')
+				 then /\A([-+]?\d{1,4})/
+				 else /\A([-+]?\d{1,})/
+				 end, '')
+	  val = $1.to_i
+	  e.year = val
+	when 'y', 'Ey', 'Oy'
+	  return unless str.sub!(/\A(\d{1,2})/, '')
+	  val = $1.to_i
+	  return unless (0..99) === val
+	  e.year = val
+	  e._cent ||= if val >= 69 then 19 else 20 end
+	when 'Z', /\A:{0,3}z/
+	  return unless str.sub!(/\A((?:gmt|utc?)?[-+]\d+(?:[,.:]\d+(?::\d+)?)?
+				    |[[:alpha:].\s]+(?:standard|daylight)\s+time\b
+				    |[[:alpha:]]+(?:\s+dst)?\b
+				    )/ix, '')
+	  val = $1
+	  e.zone = val
+	  offset = zone_to_diff(val)
+	  e.offset = offset
+	when '%'
+	  return unless str.sub!(/\A%/, '')
+	when '+'
+	  return unless _strptime_i(str, '%a %b %e %H:%M:%S %Z %Y', e)
+	else
+	  return unless str.sub!(Regexp.new('\\A' + Regexp.quote(a)), '')
+	end
+      else
+	case c
+	when /\A\s/
+	  str.sub!(/\A\s+/, '')
+	else
+	  return unless str.sub!(Regexp.new('\\A' + Regexp.quote(a)), '')
+	end
+      end
+    end
+  end
+
+  private_class_method :_strptime_i
+
+  def self._strptime(str, fmt='%F')
+    str = str.dup
+    e = Format::Bag.new
+    return unless _strptime_i(str, fmt, e)
+
+    if e._cent
+      if e.cwyear
+	e.cwyear += e._cent * 100
+      end
+      if e.year
+	e.  year += e._cent * 100
+      end
+    end
+
+    if e._merid
+      if e.hour
+	e.hour %= 12
+	e.hour += e._merid
+      end
+    end
+
+    unless str.empty?
+      e.leftover = str
+    end
+
+    e.to_hash
+  end
+
+  def self.s3e(e, y, m, d, bc=false)
+    unless String === m
+      m = m.to_s
+    end
+
+    if y && m && !d
+      y, m, d = d, y, m
+    end
+
+    if y == nil
+      if d && d.size > 2
+	y = d
+	d = nil
+      end
+      if d && d[0,1] == "'"
+	y = d
+	d = nil
+      end
+    end
+
+    if y
+      y.scan(/(\d+)(.+)?/)
+      if $2
+	y, d = d, $1
+      end
+    end
+
+    if m
+      if m[0,1] == "'" || m.size > 2
+	y, m, d = m, d, y # us -> be
+      end
+    end
+
+    if d
+      if d[0,1] == "'" || d.size > 2
+	y, d = d, y
+      end
+    end
+
+    if y
+      y =~ /([-+])?(\d+)/
+      if $1 || $2.size > 2
+	c = false
+      end
+      iy = $&.to_i
+      if bc
+	iy = -iy + 1
+      end
+      e.year = iy
+    end
+
+    if m
+      m =~ /\d+/
+      e.mon = $&.to_i
+    end
+
+    if d
+      d =~ /\d+/
+      e.mday = $&.to_i
+    end
+
+    if c != nil
+      e._comp = c
+    end
+
+  end
+
+  private_class_method :s3e
+
+  def self._parse_day(str, e) # :nodoc:
+    if str.sub!(/\b(#{Format::ABBR_DAYS.keys.join('|')})[^-\d\s]*/io, ' ')
+      e.wday = Format::ABBR_DAYS[$1.downcase]
+      true
+=begin
+    elsif str.sub!(/\b(?!\dth)(su|mo|tu|we|th|fr|sa)\b/i, ' ')
+      e.wday = %w(su mo tu we th fr sa).index($1.downcase)
+      true
+=end
+    end
+  end
+
+  def self._parse_time(str, e) # :nodoc:
+    if str.sub!(
+		/(
+		   (?:
+		     \d+\s*:\s*\d+
+		     (?:
+		       \s*:\s*\d+(?:[,.]\d*)?
+		     )?
+		   |
+		     \d+\s*h(?:\s*\d+m?(?:\s*\d+s?)?)?
+		   )
+		   (?:
+		     \s*
+		     [ap](?:m\b|\.m\.)
+		   )?
+		 |
+		   \d+\s*[ap](?:m\b|\.m\.)
+		 )
+		 (?:
+		   \s*
+		   (
+		     (?:gmt|utc?)?[-+]\d+(?:[,.:]\d+(?::\d+)?)?
+		   |
+		     [[:alpha:].\s]+(?:standard|daylight)\stime\b
+		   |
+		     [[:alpha:]]+(?:\sdst)?\b
+		   )
+		 )?
+		/ix,
+		' ')
+
+      t = $1
+      e.zone = $2 if $2
+
+      t =~ /\A(\d+)h?
+	      (?:\s*:?\s*(\d+)m?
+		(?:
+		  \s*:?\s*(\d+)(?:[,.](\d+))?s?
+		)?
+	      )?
+	    (?:\s*([ap])(?:m\b|\.m\.))?/ix
+
+      e.hour = $1.to_i
+      e.min = $2.to_i if $2
+      e.sec = $3.to_i if $3
+      e.sec_fraction = Rational($4.to_i, 10**$4.size) if $4
+
+      if $5
+	e.hour %= 12
+	if $5.downcase == 'p'
+	  e.hour += 12
+	end
+      end
+      true
+    end
+  end
+
+=begin
+  def self._parse_beat(str, e) # :nodoc:
+    if str.sub!(/@\s*(\d+)(?:[,.](\d*))?/, ' ')
+      beat = Rational($1.to_i)
+      beat += Rational($2.to_i, 10**$2.size) if $2
+      secs = Rational(beat, 1000)
+      h, min, s, fr = self.day_fraction_to_time(secs)
+      e.hour = h
+      e.min = min
+      e.sec = s
+      e.sec_fraction = fr * 86400
+      e.zone = '+01:00'
+      true
+    end
+  end
+=end
+
+  def self._parse_eu(str, e) # :nodoc:
+    if str.sub!(
+		/'?(\d+)[^-\d\s]*
+		 \s*
+		 (#{Format::ABBR_MONTHS.keys.join('|')})[^-\d\s']*
+		 (?:
+		   \s*
+		   (c(?:e|\.e\.)|b(?:ce|\.c\.e\.)|a(?:d|\.d\.)|b(?:c|\.c\.))?
+		   \s*
+		   ('?-?\d+(?:(?:st|nd|rd|th)\b)?)
+		 )?
+		/iox,
+		' ') # '
+      s3e(e, $4, Format::ABBR_MONTHS[$2.downcase], $1,
+	  $3 && $3[0,1].downcase == 'b')
+      true
+    end
+  end
+
+  def self._parse_us(str, e) # :nodoc:
+    if str.sub!(
+		/\b(#{Format::ABBR_MONTHS.keys.join('|')})[^-\d\s']*
+		 \s*
+		 ('?\d+)[^-\d\s']*
+		 (?:
+		   \s*
+		   (c(?:e|\.e\.)|b(?:ce|\.c\.e\.)|a(?:d|\.d\.)|b(?:c|\.c\.))?
+		   \s*
+		   ('?-?\d+)
+		 )?
+		/iox,
+		' ') # '
+      s3e(e, $4, Format::ABBR_MONTHS[$1.downcase], $2,
+	  $3 && $3[0,1].downcase == 'b')
+      true
+    end
+  end
+
+  def self._parse_iso(str, e) # :nodoc:
+    if str.sub!(/('?[-+]?\d+)-(\d+)-('?-?\d+)/, ' ')
+      s3e(e, $1, $2, $3)
+      true
+    end
+  end
+
+  def self._parse_iso2(str, e) # :nodoc:
+    if str.sub!(/\b(\d{2}|\d{4})?-?w(\d{2})(?:-?(\d))?\b/i, ' ')
+      e.cwyear = $1.to_i if $1
+      e.cweek = $2.to_i
+      e.cwday = $3.to_i if $3
+      true
+    elsif str.sub!(/-w-(\d)\b/i, ' ')
+      e.cwday = $1.to_i
+      true
+    elsif str.sub!(/--(\d{2})?-(\d{2})\b/, ' ')
+      e.mon = $1.to_i if $1
+      e.mday = $2.to_i
+      true
+    elsif str.sub!(/--(\d{2})(\d{2})?\b/, ' ')
+      e.mon = $1.to_i
+      e.mday = $2.to_i if $2
+      true
+    elsif /[,.](\d{2}|\d{4})-\d{3}\b/ !~ str &&
+	str.sub!(/\b(\d{2}|\d{4})-(\d{3})\b/, ' ')
+      e.year = $1.to_i
+      e.yday = $2.to_i
+      true
+    elsif /\d-\d{3}\b/ !~ str &&
+	str.sub!(/\b-(\d{3})\b/, ' ')
+      e.yday = $1.to_i
+      true
+    end
+  end
+
+  def self._parse_jis(str, e) # :nodoc:
+    if str.sub!(/\b([mtsh])(\d+)\.(\d+)\.(\d+)/i, ' ')
+      era = { 'm'=>1867,
+	      't'=>1911,
+	      's'=>1925,
+	      'h'=>1988
+	  }[$1.downcase]
+      e.year = $2.to_i + era
+      e.mon = $3.to_i
+      e.mday = $4.to_i
+      true
+    end
+  end
+
+  def self._parse_vms(str, e) # :nodoc:
+    if str.sub!(/('?-?\d+)-(#{Format::ABBR_MONTHS.keys.join('|')})[^-]*
+		-('?-?\d+)/iox, ' ')
+      s3e(e, $3, Format::ABBR_MONTHS[$2.downcase], $1)
+      true
+    elsif str.sub!(/\b(#{Format::ABBR_MONTHS.keys.join('|')})[^-]*
+		-('?-?\d+)(?:-('?-?\d+))?/iox, ' ')
+      s3e(e, $3, Format::ABBR_MONTHS[$1.downcase], $2)
+      true
+    end
+  end
+
+  def self._parse_sla(str, e) # :nodoc:
+    if str.sub!(%r|('?-?\d+)/\s*('?\d+)(?:\D\s*('?-?\d+))?|, ' ') # '
+      s3e(e, $1, $2, $3)
+      true
+    end
+  end
+
+  def self._parse_dot(str, e) # :nodoc:
+    if str.sub!(%r|('?-?\d+)\.\s*('?\d+)\.\s*('?-?\d+)|, ' ') # '
+      s3e(e, $1, $2, $3)
+      true
+    end
+  end
+
+  def self._parse_year(str, e) # :nodoc:
+    if str.sub!(/'(\d+)\b/, ' ')
+      e.year = $1.to_i
+      true
+    end
+  end
+
+  def self._parse_mon(str, e) # :nodoc:
+    if str.sub!(/\b(#{Format::ABBR_MONTHS.keys.join('|')})\S*/io, ' ')
+      e.mon = Format::ABBR_MONTHS[$1.downcase]
+      true
+    end
+  end
+
+  def self._parse_mday(str, e) # :nodoc:
+    if str.sub!(/(\d+)(st|nd|rd|th)\b/i, ' ')
+      e.mday = $1.to_i
+      true
+    end
+  end
+
+  def self._parse_ddd(str, e) # :nodoc:
+    if str.sub!(
+		/([-+]?)(\d{2,14})
+		  (?:
+		    \s*
+		    t?
+		    \s*
+		    (\d{2,6})?(?:[,.](\d*))?
+		  )?
+		  (?:
+		    \s*
+		    (
+		      z\b
+		    |
+		      [-+]\d{1,4}\b
+		    |
+		      \[[-+]?\d[^\]]*\]
+		    )
+		  )?
+		/ix,
+		' ')
+      case $2.size
+      when 2
+	if $3.nil? && $4
+	  e.sec  = $2[-2, 2].to_i
+	else
+	  e.mday = $2[ 0, 2].to_i
+	end
+      when 4
+	if $3.nil? && $4
+	  e.sec  = $2[-2, 2].to_i
+	  e.min  = $2[-4, 2].to_i
+	else
+	  e.mon  = $2[ 0, 2].to_i
+	  e.mday = $2[ 2, 2].to_i
+	end
+      when 6
+	if $3.nil? && $4
+	  e.sec  = $2[-2, 2].to_i
+	  e.min  = $2[-4, 2].to_i
+	  e.hour = $2[-6, 2].to_i
+	else
+	  e.year = ($1 + $2[ 0, 2]).to_i
+	  e.mon  = $2[ 2, 2].to_i
+	  e.mday = $2[ 4, 2].to_i
+	end
+      when 8, 10, 12, 14
+	if $3.nil? && $4
+	  e.sec  = $2[-2, 2].to_i
+	  e.min  = $2[-4, 2].to_i
+	  e.hour = $2[-6, 2].to_i
+	  e.mday = $2[-8, 2].to_i
+	  if $2.size >= 10
+	    e.mon  = $2[-10, 2].to_i
+	  end
+	  if $2.size == 12
+	    e.year = ($1 + $2[-12, 2]).to_i
+	  end
+	  if $2.size == 14
+	    e.year = ($1 + $2[-14, 4]).to_i
+	    e._comp = false
+	  end
+	else
+	  e.year = ($1 + $2[ 0, 4]).to_i
+	  e.mon  = $2[ 4, 2].to_i
+	  e.mday = $2[ 6, 2].to_i
+	  e.hour = $2[ 8, 2].to_i if $2.size >= 10
+	  e.min  = $2[10, 2].to_i if $2.size >= 12
+	  e.sec  = $2[12, 2].to_i if $2.size >= 14
+	  e._comp = false
+	end
+      when 3
+	if $3.nil? && $4
+	  e.sec  = $2[-2, 2].to_i
+	  e.min  = $2[-3, 1].to_i
+	else
+	  e.yday = $2[ 0, 3].to_i
+	end
+      when 5
+	if $3.nil? && $4
+	  e.sec  = $2[-2, 2].to_i
+	  e.min  = $2[-4, 2].to_i
+	  e.hour = $2[-5, 1].to_i
+	else
+	  e.year = ($1 + $2[ 0, 2]).to_i
+	  e.yday = $2[ 2, 3].to_i
+	end
+      when 7
+	if $3.nil? && $4
+	  e.sec  = $2[-2, 2].to_i
+	  e.min  = $2[-4, 2].to_i
+	  e.hour = $2[-6, 2].to_i
+	  e.mday = $2[-7, 1].to_i
+	else
+	  e.year = ($1 + $2[ 0, 4]).to_i
+	  e.yday = $2[ 4, 3].to_i
+	end
+      end
+      if $3
+	if $4
+	  case $3.size
+	  when 2, 4, 6
+	    e.sec  = $3[-2, 2].to_i
+	    e.min  = $3[-4, 2].to_i if $3.size >= 4
+	    e.hour = $3[-6, 2].to_i if $3.size >= 6
+	  end
+	else
+	  case $3.size
+	  when 2, 4, 6
+	    e.hour = $3[ 0, 2].to_i
+	    e.min  = $3[ 2, 2].to_i if $3.size >= 4
+	    e.sec  = $3[ 4, 2].to_i if $3.size >= 6
+	  end
+	end
+      end
+      if $4
+	e.sec_fraction = Rational($4.to_i, 10**$4.size)
+      end
+      if $5
+	e.zone = $5
+	if e.zone[0,1] == '['
+	  o, n, = e.zone[1..-2].split(':')
+	  e.zone = n || o
+	  if /\A\d/ =~ o
+	    o = format('+%s', o)
+	  end
+	  e.offset = zone_to_diff(o)
+	end
+      end
+      true
+    end
+  end
+
+  private_class_method :_parse_day, :_parse_time, # :_parse_beat,
+	:_parse_eu, :_parse_us, :_parse_iso, :_parse_iso2,
+	:_parse_jis, :_parse_vms, :_parse_sla, :_parse_dot,
+	:_parse_year, :_parse_mon, :_parse_mday, :_parse_ddd
+
+  def self._parse(str, comp=true)
+    str = str.dup
+
+    e = Format::Bag.new
+
+    e._comp = comp
+
+    str.gsub!(/[^-+',.\/:@[:alnum:]\[\]]+/, ' ')
+
+    _parse_time(str, e) # || _parse_beat(str, e)
+    _parse_day(str, e)
+
+    _parse_eu(str, e)     ||
+    _parse_us(str, e)     ||
+    _parse_iso(str, e)    ||
+    _parse_jis(str, e)    ||
+    _parse_vms(str, e)    ||
+    _parse_sla(str, e)    ||
+    _parse_dot(str, e)    ||
+    _parse_iso2(str, e)   ||
+    _parse_year(str, e)   ||
+    _parse_mon(str, e)    ||
+    _parse_mday(str, e)   ||
+    _parse_ddd(str, e)
+
+    if str.sub!(/\b(bc\b|bce\b|b\.c\.|b\.c\.e\.)/i, ' ')
+      if e.year
+	e.year = -e.year + 1
+      end
+    end
+
+    if str.sub!(/\A\s*(\d{1,2})\s*\z/, ' ')
+      if e.hour && !e.mday
+	v = $1.to_i
+	if (1..31) === v
+	  e.mday = v
+	end
+      end
+      if e.mday && !e.hour
+	v = $1.to_i
+	if (0..24) === v
+	  e.hour = v
+	end
+      end
+    end
+
+    if e._comp
+      if e.cwyear
+	if e.cwyear >= 0 && e.cwyear <= 99
+	  e.cwyear += if e.cwyear >= 69
+		      then 1900 else 2000 end
+	end
+      end
+      if e.year
+	if e.year >= 0 && e.year <= 99
+	  e.year += if e.year >= 69
+		    then 1900 else 2000 end
+	end
+      end
+    end
+
+    e.offset ||= zone_to_diff(e.zone) if e.zone
+
+    e.to_hash
+  end
+
+  def self._iso8601(str) # :nodoc:
+    if /\A\s*(([-+]?\d{2,}|-)-\d{2}-\d{2}|
+	      ([-+]?\d{2,})?-\d{3}|
+	      (\d{2}|\d{4})?-w\d{2}-\d|
+	      -w-\d)
+	(t
+	\d{2}:\d{2}(:\d{2}([,.]\d+)?)?
+	(z|[-+]\d{2}(:?\d{2})?)?)?\s*\z/ix =~ str
+      _parse(str)
+    elsif /\A\s*(([-+]?(\d{2}|\d{4})|--)\d{2}\d{2}|
+	      ([-+]?(\d{2}|\d{4}))?\d{3}|-\d{3}|
+	      (\d{2}|\d{4})?w\d{2}\d)
+	(t?
+	\d{2}\d{2}(\d{2}([,.]\d+)?)?
+	(z|[-+]\d{2}(\d{2})?)?)?\s*\z/ix =~ str
+      _parse(str)
+    elsif /\A\s*(\d{2}:\d{2}(:\d{2}([,.]\d+)?)?
+	(z|[-+]\d{2}(:?\d{2})?)?)?\s*\z/ix =~ str
+      _parse(str)
+    elsif /\A\s*(\d{2}\d{2}(\d{2}([,.]\d+)?)?
+	(z|[-+]\d{2}(\d{2})?)?)?\s*\z/ix =~ str
+      _parse(str)
+    end
+  end
+
+  def self._rfc3339(str) # :nodoc:
+    if /\A\s*-?\d{4}-\d{2}-\d{2} # allow minus, anyway
+	(t|\s)
+	\d{2}:\d{2}:\d{2}(\.\d+)?
+	(z|[-+]\d{2}:\d{2})\s*\z/ix =~ str
+      _parse(str)
+    end
+  end
+
+  def self._xmlschema(str) # :nodoc:
+    if /\A\s*(-?\d{4,})(?:-(\d{2})(?:-(\d{2}))?)?
+	(?:t
+	  (\d{2}):(\d{2}):(\d{2})(?:\.(\d+))?)?
+	(z|[-+]\d{2}:\d{2})?\s*\z/ix =~ str
+      e = Format::Bag.new
+      e.year = $1.to_i
+      e.mon = $2.to_i if $2
+      e.mday = $3.to_i if $3
+      e.hour = $4.to_i if $4
+      e.min = $5.to_i if $5
+      e.sec = $6.to_i if $6
+      e.sec_fraction = Rational($7.to_i, 10**$7.size) if $7
+      if $8
+	e.zone = $8
+	e.offset = zone_to_diff($8)
+      end
+      e.to_hash
+    elsif /\A\s*(\d{2}):(\d{2}):(\d{2})(?:\.(\d+))?
+	(z|[-+]\d{2}:\d{2})?\s*\z/ix =~ str
+      e = Format::Bag.new
+      e.hour = $1.to_i if $1
+      e.min = $2.to_i if $2
+      e.sec = $3.to_i if $3
+      e.sec_fraction = Rational($4.to_i, 10**$4.size) if $4
+      if $5
+	e.zone = $5
+	e.offset = zone_to_diff($5)
+      end
+      e.to_hash
+    elsif /\A\s*(?:--(\d{2})(?:-(\d{2}))?|---(\d{2}))
+	(z|[-+]\d{2}:\d{2})?\s*\z/ix =~ str
+      e = Format::Bag.new
+      e.mon = $1.to_i if $1
+      e.mday = $2.to_i if $2
+      e.mday = $3.to_i if $3
+      if $4
+	e.zone = $4
+	e.offset = zone_to_diff($4)
+      end
+      e.to_hash
+    end
+  end
+
+  def self._rfc2822(str) # :nodoc:
+    if /\A\s*(?:(?:#{Format::ABBR_DAYS.keys.join('|')})\s*,\s+)?
+	\d{1,2}\s+
+	(?:#{Format::ABBR_MONTHS.keys.join('|')})\s+
+	-?(\d{2,})\s+ # allow minus, anyway
+	\d{2}:\d{2}(:\d{2})?\s*
+	(?:[-+]\d{4}|ut|gmt|e[sd]t|c[sd]t|m[sd]t|p[sd]t|[a-ik-z])\s*\z/iox =~ str
+      e = _parse(str, false)
+      if $1.size < 4
+	if e[:year] < 50
+	  e[:year] += 2000
+	elsif e[:year] < 1000
+	  e[:year] += 1900
+	end
+      end
+      e
+    end
+  end
+
+  class << self; alias_method :_rfc822, :_rfc2822 end
+
+  def self._httpdate(str) # :nodoc:
+    if /\A\s*(#{Format::ABBR_DAYS.keys.join('|')})\s*,\s+
+	\d{2}\s+
+	(#{Format::ABBR_MONTHS.keys.join('|')})\s+
+	-?\d{4}\s+ # allow minus, anyway
+	\d{2}:\d{2}:\d{2}\s+
+	gmt\s*\z/iox =~ str
+      _rfc2822(str)
+    elsif /\A\s*(#{Format::DAYS.keys.join('|')})\s*,\s+
+	\d{2}\s*-\s*
+	(#{Format::ABBR_MONTHS.keys.join('|')})\s*-\s*
+	\d{2}\s+
+	\d{2}:\d{2}:\d{2}\s+
+	gmt\s*\z/iox =~ str
+      _parse(str)
+    elsif /\A\s*(#{Format::ABBR_DAYS.keys.join('|')})\s+
+	(#{Format::ABBR_MONTHS.keys.join('|')})\s+
+	\d{1,2}\s+
+	\d{2}:\d{2}:\d{2}\s+
+	\d{4}\s*\z/iox =~ str
+      _parse(str)
+    end
+  end
+
+  def self._jisx0301(str) # :nodoc:
+    if /\A\s*[mtsh]?\d{2}\.\d{2}\.\d{2}
+	(t
+	(\d{2}:\d{2}(:\d{2}([,.]\d*)?)?
+	(z|[-+]\d{2}(:?\d{2})?)?)?)?\s*\z/ix =~ str
+      if /\A\s*\d/ =~ str
+	_parse(str.sub(/\A\s*(\d)/, 'h\1'))
+      else
+	_parse(str)
+      end
+    else
+      _iso8601(str)
+    end
+  end
+
+  t = Module.new do
+
+    private
+
+    def zone_to_diff(zone) # :nodoc:
+      zone = zone.downcase
+      if zone.sub!(/\s+(standard|daylight)\s+time\z/, '')
+	dst = $1 == 'daylight'
+      else
+	dst = zone.sub!(/\s+dst\z/, '')
+      end
+      if Format::ZONES.include?(zone)
+	offset = Format::ZONES[zone]
+	offset += 3600 if dst
+      elsif zone.sub!(/\A(?:gmt|utc?)?([-+])/, '')
+	sign = $1
+	if zone.include?(':')
+	  hour, min, sec, = zone.split(':')
+	elsif zone.include?(',') || zone.include?('.')
+	  hour, fr, = zone.split(/[,.]/)
+	  min = Rational(fr.to_i, 10**fr.size) * 60
+	else
+	  case zone.size
+	  when 3
+	    hour = zone[0,1]
+	    min = zone[1,2]
+	  else
+	    hour = zone[0,2]
+	    min = zone[2,2]
+	    sec = zone[4,2]
+	  end
+	end
+	offset = hour.to_i * 3600 + min.to_i * 60 + sec.to_i
+	offset *= -1 if sign == '-'
+      end
+      offset
+    end
+
+  end
+
+  extend  t
+  include t
+
+end
+
+class DateTime < Date
+
+  def strftime(fmt='%FT%T%:z')
+    super(fmt)
+  end
+
+  def self._strptime(str, fmt='%FT%T%z')
+    super(str, fmt)
+  end
+
+  def iso8601_timediv(n) # :nodoc:
+    strftime('T%T' +
+	     if n < 1
+	       ''
+	     else
+	       '.%0*d' % [n, (sec_fraction / Rational(1, 10**n)).round]
+	     end +
+	     '%:z')
+  end
+
+  private :iso8601_timediv
+
+  def iso8601(n=0)
+    super() + iso8601_timediv(n)
+  end
+
+  def rfc3339(n=0) iso8601(n) end
+
+  def xmlschema(n=0) iso8601(n) end # :nodoc:
+
+  def jisx0301(n=0)
+    super() + iso8601_timediv(n)
+  end
+
+end