note
	description: "Absolute temporal values composed of a date and a time"
	legal: "See notice at end of class."
	status: "See notice at end of class."
	date: "$Date: 2017-03-29 12:26:46 +0000 (Wed, 29 Mar 2017) $"
	revision: "$Revision: 100065 $"
	access: date, time
	eis: "name=Obtaining a DATE from a DATE_TIME and vice versa", "src=$(ISE_DOC_UUID)/195849fc-1a9c-d734-2d2b-acae78133886#Obtaining_a_DATE_from_a_DATE_TIME_and_vice_versa", "tag=EiffelTime"
	eis: "name=DATE / TIME to STRING Conversion", "src=$(ISE_DOC_UUID)/88972ba4-694b-8558-b0c8-87b1fc40afc4", "tag=EiffelTime"

class interface
	DATE_TIME

create 
	make (y, mo, d, h, mi, s: INTEGER_32)
			-- Set year, month day to y, mo, d.
			-- Set hour, minute, second to h, mi, s.
		require
			correct_date_time: is_correct_date_time (y, mo, d, h, mi, s.to_double, False)
		ensure
			year_set: year = y
			month_set: month = mo
			day_set: day = d
			hour_set: hour = h
			minute_set: minute = mi
			second_set: second = s

	make_fine (y, mo, d, h, mi: INTEGER_32; s: REAL_64)
			-- Set year, month day to y, mo, d.
			-- Set hour, minute, second to h, m, s.
		require
			correct_date_time: is_correct_date_time (y, mo, d, h, mi, s, False)
		ensure
			year_set: year = y
			month_set: month = mo
			day_set: day = d
			hour_set: hour = h
			minute_set: minute = mi
			second_set: fine_second = s

	make_by_date_time (d: DATE; t: TIME)
			-- Set date to d and time to t
		require
			d_exists: d /= Void
			t_exists: t /= Void
		ensure
			date_set: date = d
			time_set: time = t

	make_by_date (d: DATE)
			-- Set date to d and time to origin of time.
		require
			d_exists: d /= Void
		ensure
			date_set: date = d
			time_set: time.is_equal (time.Origin)

	make_now
			-- Get the date and the time from the system.

	make_now_utc
			-- Get the date and the time from the system.

	make_from_epoch (s: INTEGER_32)
			-- Create a new date time from the number of
			-- seconds since epoch (1 Jan 1970 at 00:00:00).

	make_from_string (s: STRING_8; code: STRING_8)
			-- Initialize from a "standard" string of form
			-- code.
			-- (For 2-digit year specifications, the current century is used as
			-- base century.)
		require
			s_exists: s /= Void
			c_exists: code /= Void
			date_time_valid: date_time_valid (s, code)

	make_from_string_with_base (s: STRING_8; code: STRING_8; base: INTEGER_32)
			-- Initialize from a "standard" string of form
			-- code with base century base.
		require
			s_exists: s /= Void
			c_exists: code /= Void
			base_valid: base > 0 and (base \\ 100 = 0)
			date_time_valid: date_time_valid_with_base (s, code, base)

	make_from_string_default (s: STRING_8)
			-- Initialize from a "standard" string of form
			-- default_format_string.
			-- (For 2-digit year specifications, the current century is used as
			-- base century.)
		require
			s_exists: s /= Void
			date_time_valid: date_time_valid (s, default_format_string)

	make_from_string_default_with_base (s: STRING_8; base: INTEGER_32)
			-- Initialize from a "standard" string of form
			-- default_format_string with base century base.
		require
			s_exists: s /= Void
			base_valid: base > 0 and (base \\ 100 = 0)
			date_time_valid: date_time_valid_with_base (s, default_format_string, base)

feature -- Initialization

	make (y, mo, d, h, mi, s: INTEGER_32)
			-- Set year, month day to y, mo, d.
			-- Set hour, minute, second to h, mi, s.
		require
			correct_date_time: is_correct_date_time (y, mo, d, h, mi, s.to_double, False)
		ensure
			year_set: year = y
			month_set: month = mo
			day_set: day = d
			hour_set: hour = h
			minute_set: minute = mi
			second_set: second = s

	make_by_date (d: DATE)
			-- Set date to d and time to origin of time.
		require
			d_exists: d /= Void
		ensure
			date_set: date = d
			time_set: time.is_equal (time.Origin)

	make_by_date_time (d: DATE; t: TIME)
			-- Set date to d and time to t
		require
			d_exists: d /= Void
			t_exists: t /= Void
		ensure
			date_set: date = d
			time_set: time = t

	make_fine (y, mo, d, h, mi: INTEGER_32; s: REAL_64)
			-- Set year, month day to y, mo, d.
			-- Set hour, minute, second to h, m, s.
		require
			correct_date_time: is_correct_date_time (y, mo, d, h, mi, s, False)
		ensure
			year_set: year = y
			month_set: month = mo
			day_set: day = d
			hour_set: hour = h
			minute_set: minute = mi
			second_set: fine_second = s

	make_from_epoch (s: INTEGER_32)
			-- Create a new date time from the number of
			-- seconds since epoch (1 Jan 1970 at 00:00:00).

	make_from_string (s: STRING_8; code: STRING_8)
			-- Initialize from a "standard" string of form
			-- code.
			-- (For 2-digit year specifications, the current century is used as
			-- base century.)
		require
			s_exists: s /= Void
			c_exists: code /= Void
			date_time_valid: date_time_valid (s, code)

	make_from_string_default (s: STRING_8)
			-- Initialize from a "standard" string of form
			-- default_format_string.
			-- (For 2-digit year specifications, the current century is used as
			-- base century.)
		require
			s_exists: s /= Void
			date_time_valid: date_time_valid (s, default_format_string)

	make_from_string_default_with_base (s: STRING_8; base: INTEGER_32)
			-- Initialize from a "standard" string of form
			-- default_format_string with base century base.
		require
			s_exists: s /= Void
			base_valid: base > 0 and (base \\ 100 = 0)
			date_time_valid: date_time_valid_with_base (s, default_format_string, base)

	make_from_string_with_base (s: STRING_8; code: STRING_8; base: INTEGER_32)
			-- Initialize from a "standard" string of form
			-- code with base century base.
		require
			s_exists: s /= Void
			c_exists: code /= Void
			base_valid: base > 0 and (base \\ 100 = 0)
			date_time_valid: date_time_valid_with_base (s, code, base)

	make_now
			-- Get the date and the time from the system.

	make_now_utc
			-- Get the date and the time from the system.
	
feature -- Access

	date: DATE
			-- Date of the current object

	date_default_format_string: STRING_8
			-- Default output format for dates
			-- (from DATE_CONSTANTS)

	date_duration: DATE_DURATION
			-- Definite duration between origin of date and current date

	Date_time_tools: DATE_TIME_TOOLS
			-- Tools for outputting dates and times in different formats
			-- (from TIME_UTILITY)

	day: INTEGER_32
			-- Day of the current object
			-- (from DATE_TIME_MEASUREMENT)
		require -- from  DATE_MEASUREMENT
			True
		ensure -- from DATE_TIME_MEASUREMENT
			same_day: Result = date.day

	days: INTEGER_32
			-- Number of days elapsed since Origin

	days_in_i_th_month (i, y: INTEGER_32): INTEGER_32
			-- Number of days in the i th month at year y
			-- (from DATE_CONSTANTS)
		require -- from DATE_CONSTANTS
			i_large_enough: i >= 1
			i_small_enough: i <= Months_in_year

	Days_in_leap_year: INTEGER_32 = 366
			-- Number of days in a leap year
			-- (from DATE_CONSTANTS)

	Days_in_non_leap_year: INTEGER_32 = 365
			-- Number of days in a non-leap year
			-- (from DATE_CONSTANTS)

	Days_in_week: INTEGER_32 = 7
			-- Number of days in a week
			-- (from DATE_CONSTANTS)

	days_text: ARRAY [STRING_8]
			-- Short text representation of days
			-- (from DATE_CONSTANTS)

	default_format_string: STRING_8
			-- Default output format string
			-- (from TIME_UTILITY)

	fine_second: REAL_64
			-- Representation of second with decimals
			-- (from DATE_TIME_MEASUREMENT)
		require -- from  TIME_MEASUREMENT
			True
		ensure -- from DATE_TIME_MEASUREMENT
			same_fine_second: Result = time.fine_second

	fractional_second: REAL_64
			-- Fractional part of fine_second
			-- (from TIME_VALUE)

	generating_type: TYPE [detachable DATE_TIME]
			-- Type of current object
			-- (type of which it is a direct instance)
			-- (from ANY)
		ensure -- from ANY
			generating_type_not_void: Result /= Void

	generator: STRING_8
			-- Name of current object's generating class
			-- (base class of the type of which it is a direct instance)
			-- (from ANY)
		ensure -- from ANY
			generator_not_void: Result /= Void
			generator_not_empty: not Result.is_empty

	hour: INTEGER_32
			-- Hour of the current object
			-- (from DATE_TIME_MEASUREMENT)
		require -- from  TIME_MEASUREMENT
			True
		ensure -- from DATE_TIME_MEASUREMENT
			same_hour: Result = time.hour

	Hours_in_day: INTEGER_32 = 24
			-- Number of hours in a day
			-- (from TIME_CONSTANTS)

	long_days_text: ARRAY [STRING_8]
			-- Long text representation of days
			-- (from DATE_CONSTANTS)

	long_months_text: ARRAY [STRING_8]
			-- Long text representation of months
			-- (from DATE_CONSTANTS)

	Max_weeks_in_year: INTEGER_32 = 53
			-- Maximun number of weeks in a year
			-- (from DATE_CONSTANTS)

	minute: INTEGER_32
			-- Minute of the current object
			-- (from DATE_TIME_MEASUREMENT)
		require -- from  TIME_MEASUREMENT
			True
		ensure -- from DATE_TIME_MEASUREMENT
			same_minute: Result = time.minute

	Minutes_in_hour: INTEGER_32 = 60
			-- Number of minutes in an hour
			-- (from TIME_CONSTANTS)

	month: INTEGER_32
			-- Month of the current object
			-- (from DATE_TIME_MEASUREMENT)
		require -- from  DATE_MEASUREMENT
			True
		ensure -- from DATE_TIME_MEASUREMENT
			same_month: Result = date.month

	Months_in_year: INTEGER_32 = 12
			-- Number of months in year
			-- (from DATE_CONSTANTS)

	months_text: ARRAY [STRING_8]
			-- Short text representation of months
			-- (from DATE_CONSTANTS)

	Origin: DATE_TIME
			-- Origin date with origin time
		ensure -- from ABSOLUTE
			result_exists: Result /= Void

	second: INTEGER_32
			-- Second of the current object
			-- (from DATE_TIME_MEASUREMENT)
		require -- from  TIME_MEASUREMENT
			True
		ensure -- from DATE_TIME_MEASUREMENT
			same_second: Result = time.second

	seconds: INTEGER_32
			-- Number of seconds elapsed from midnight of the current date

	Seconds_in_day: INTEGER_32 = 86400
			-- Number of seconds in an hour
			-- (from TIME_CONSTANTS)

	Seconds_in_hour: INTEGER_32 = 3600
			-- Number of seconds in an hour
			-- (from TIME_CONSTANTS)

	Seconds_in_minute: INTEGER_32 = 60
			-- Number of seconds in a minute
			-- (from TIME_CONSTANTS)

	time: TIME
			-- Time of the current object

	time_default_format_string: STRING_8
			-- Default output format for times
			-- (from TIME_CONSTANTS)

	time_duration: TIME_DURATION
			-- Duration elapsed from midnight of the current date

	year: INTEGER_32
			-- Year of the current object
			-- (from DATE_TIME_MEASUREMENT)
		require -- from  DATE_MEASUREMENT
			True
		ensure -- from DATE_TIME_MEASUREMENT
			same_year: Result = date.year
	
feature -- Measurement

	duration: DATE_TIME_DURATION
			-- Definite duration elapsed from Origin
		require -- from  ABSOLUTE
			True
		ensure then
			definite_result: Result.definite
	
feature -- Comparison

	frozen deep_equal (a: detachable ANY; b: like arg #1): BOOLEAN
			-- Are a and b either both void
			-- or attached to isomorphic object structures?
			-- (from ANY)
		ensure -- from ANY
			instance_free: class
			shallow_implies_deep: standard_equal (a, b) implies Result
			both_or_none_void: (a = Void) implies (Result = (b = Void))
			same_type: (Result and (a /= Void)) implies (b /= Void and then a.same_type (b))
			symmetric: Result implies deep_equal (b, a)

	frozen equal (a: detachable ANY; b: like arg #1): BOOLEAN
			-- Are a and b either both void or attached
			-- to objects considered equal?
			-- (from ANY)
		ensure -- from ANY
			instance_free: class
			definition: Result = (a = Void and b = Void) or else ((a /= Void and b /= Void) and then a.is_equal (b))

	frozen is_deep_equal (other: DATE_TIME): BOOLEAN
			-- Are Current and other attached to isomorphic object structures?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		ensure -- from ANY
			shallow_implies_deep: standard_is_equal (other) implies Result
			same_type: Result implies same_type (other)
			symmetric: Result implies other.is_deep_equal (Current)

	is_equal (other: like Current): BOOLEAN
			-- Is the current object equal to other?
		require -- from ANY
			other_not_void: other /= Void
		ensure -- from ANY
			symmetric: Result implies other ~ Current
			consistent: standard_is_equal (other) implies Result
		ensure then -- from COMPARABLE
			trichotomy: Result = (not (Current < other) and not (other < Current))

	is_greater alias ">" (other: DATE_TIME): BOOLEAN
			-- Is current object greater than other?
			-- (from COMPARABLE)
		require -- from PART_COMPARABLE
			other_exists: other /= Void
		ensure then -- from COMPARABLE
			definition: Result = (other < Current)

	is_greater_equal alias ">=" (other: DATE_TIME): BOOLEAN
			-- Is current object greater than or equal to other?
			-- (from COMPARABLE)
		require -- from PART_COMPARABLE
			other_exists: other /= Void
		ensure then -- from COMPARABLE
			definition: Result = (other <= Current)

	is_less alias "<" (other: like Current): BOOLEAN
			-- Is the current object before other?
		require -- from PART_COMPARABLE
			other_exists: other /= Void
		ensure then -- from COMPARABLE
			asymmetric: Result implies not (other < Current)

	is_less_equal alias "<=" (other: DATE_TIME): BOOLEAN
			-- Is current object less than or equal to other?
			-- (from COMPARABLE)
		require -- from PART_COMPARABLE
			other_exists: other /= Void
		ensure then -- from COMPARABLE
			definition: Result = ((Current < other) or (Current ~ other))

	max (other: DATE_TIME): DATE_TIME
			-- The greater of current object and other
			-- (from COMPARABLE)
		require -- from COMPARABLE
			other_exists: other /= Void
		ensure -- from COMPARABLE
			current_if_not_smaller: Current >= other implies Result = Current
			other_if_smaller: Current < other implies Result = other

	min (other: DATE_TIME): DATE_TIME
			-- The smaller of current object and other
			-- (from COMPARABLE)
		require -- from COMPARABLE
			other_exists: other /= Void
		ensure -- from COMPARABLE
			current_if_not_greater: Current <= other implies Result = Current
			other_if_greater: Current > other implies Result = other

	frozen standard_equal (a: detachable ANY; b: like arg #1): BOOLEAN
			-- Are a and b either both void or attached to
			-- field-by-field identical objects of the same type?
			-- Always uses default object comparison criterion.
			-- (from ANY)
		ensure -- from ANY
			instance_free: class
			definition: Result = (a = Void and b = Void) or else ((a /= Void and b /= Void) and then a.standard_is_equal (b))

	frozen standard_is_equal (other: DATE_TIME): BOOLEAN
			-- Is other attached to an object of the same type
			-- as current object, and field-by-field identical to it?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		ensure -- from ANY
			same_type: Result implies same_type (other)
			symmetric: Result implies other.standard_is_equal (Current)

	three_way_comparison (other: DATE_TIME): INTEGER_32
			-- If current object equal to other, 0;
			-- if smaller, -1; if greater, 1
			-- (from COMPARABLE)
		require -- from COMPARABLE
			other_exists: other /= Void
		ensure -- from COMPARABLE
			equal_zero: (Result = 0) = (Current ~ other)
			smaller_negative: (Result = -1) = (Current < other)
			greater_positive: (Result = 1) = (Current > other)
	
feature -- Status report

	conforms_to (other: ANY): BOOLEAN
			-- Does type of current object conform to type
			-- of other (as per Eiffel: The Language, chapter 13)?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void

	is_leap_year (y: INTEGER_32): BOOLEAN
			-- Is year y a leap year?
			-- (from DATE_CONSTANTS)

	same_type (other: ANY): BOOLEAN
			-- Is type of current object identical to type of other?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		ensure -- from ANY
			definition: Result = (conforms_to (other) and other.conforms_to (Current))
	
feature -- Duplication

	frozen deep_copy (other: DATE_TIME)
			-- Effect equivalent to that of:
			--		copy (other . deep_twin)
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		ensure -- from ANY
			deep_equal: deep_equal (Current, other)

	frozen deep_twin: DATE_TIME
			-- New object structure recursively duplicated from Current.
			-- (from ANY)
		ensure -- from ANY
			deep_twin_not_void: Result /= Void
			deep_equal: deep_equal (Current, Result)

	frozen standard_copy (other: DATE_TIME)
			-- Copy every field of other onto corresponding field
			-- of current object.
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
			type_identity: same_type (other)
		ensure -- from ANY
			is_standard_equal: standard_is_equal (other)

	frozen standard_twin: DATE_TIME
			-- New object field-by-field identical to other.
			-- Always uses default copying semantics.
			-- (from ANY)
		ensure -- from ANY
			standard_twin_not_void: Result /= Void
			equal: standard_equal (Result, Current)

	frozen twin: DATE_TIME
			-- New object equal to Current
			-- twin calls copy; to change copying/twinning semantics, redefine copy.
			-- (from ANY)
		ensure -- from ANY
			twin_not_void: Result /= Void
			is_equal: Result ~ Current
	
feature -- Basic operations

	add (dtd: DATE_TIME_DURATION)
			-- Adds dtd to current duration
		require
			dtd_not_void: dtd /= Void

	day_add (d: INTEGER_32)
			-- Add d days to the current date.
		ensure
			days_set: days = old days + d

	frozen default: detachable DATE_TIME
			-- Default value of object's type
			-- (from ANY)

	frozen default_pointer: POINTER
			-- Default value of type POINTER
			-- (Avoid the need to write p.default for
			-- some p of type POINTER.)
			-- (from ANY)
		ensure -- from ANY
			instance_free: class

	default_rescue
			-- Process exception for routines with no Rescue clause.
			-- (Default: do nothing.)
			-- (from ANY)

	definite_duration (other: like Current): DATE_TIME_DURATION
			-- Duration from other to the current date, converted to a
			-- definite duration
		require
			other_exists: other /= Void
		ensure
			definite_result: Result.definite

	frozen do_nothing
			-- Execute a null action.
			-- (from ANY)
		ensure -- from ANY
			instance_free: class

	fine_second_add (s: REAL_64)
			-- Add s seconds to the current object.
			-- if s has decimals, fractional_second from time is modified.

	hour_add (h: INTEGER_32)
			-- Add h hours to the current time.

	minus alias "-" (other: DATE_TIME): INTERVAL [DATE_TIME]
			-- Interval between current object and other.
			-- (from ABSOLUTE)
		require -- from ABSOLUTE
			other_exists: other /= Void
			other_smaller_than_current: other <= Current
		ensure -- from ABSOLUTE
			result_exists: Result /= Void
			result_set: Result.start_bound.is_equal (other) and then Result.end_bound.is_equal (Current)

	minute_add (m: INTEGER_32)
			-- Add m minutes to the current time.

	plus alias "+" (d: DATE_TIME_DURATION): like Current
			-- Sum the current object with d
		require
			d_not_void: d /= Void
		ensure
			result_exists: Result /= Void

	relative_duration (other: like Current): DATE_TIME_DURATION
			-- Duration from other to current date
		require -- from ABSOLUTE
			other_exists: other /= Void
		ensure -- from ABSOLUTE
			result_exists: Result /= Void
		ensure then
			origin_set: equal (other, Result.origin_date_time)

	second_add (s: INTEGER_32)
			-- Add s seconds to the current time.
	
feature -- Element Change

	copy (other: like Current)
			-- set date and time with the other attributes.
		require -- from ANY
			other_not_void: other /= Void
			type_identity: same_type (other)
		ensure -- from ANY
			is_equal: Current ~ other

	set_date (d: DATE)
			-- Set date to d.
		require
			d_exists: d /= Void
		ensure
			date_set: date = d

	set_time (t: TIME)
			-- Set time to t.
		require
			t_exists: t /= Void
		ensure
			time_set: time = t
	
feature -- Output

	debug_output: STRING_8
			-- Printable representation of the current object
			-- With "standard" form: default_format_string
			-- Was declared in DATE_TIME as synonym of out.
		ensure -- from DEBUG_OUTPUT
			result_not_void: Result /= Void

	formatted_out (s: STRING_8): STRING_8
			-- Printable representation of the current object
			-- With "standard" form: s
		require
			s_exists: s /= Void

	Io: STD_FILES
			-- Handle to standard file setup
			-- (from ANY)
		ensure -- from ANY
			instance_free: class
			io_not_void: Result /= Void

	out: STRING_8
			-- Printable representation of the current object
			-- With "standard" form: default_format_string
			-- Was declared in DATE_TIME as synonym of debug_output.
		ensure -- from ANY
			out_not_void: Result /= Void

	print (o: detachable ANY)
			-- Write terse external representation of o
			-- on standard output.
			-- (from ANY)
		ensure -- from ANY
			instance_free: class

	frozen tagged_out: STRING_8
			-- New string containing terse printable representation
			-- of current object
			-- (from ANY)
		ensure -- from ANY
			tagged_out_not_void: Result /= Void
	
feature -- Platform

	Operating_environment: OPERATING_ENVIRONMENT
			-- Objects available from the operating system
			-- (from ANY)
		ensure -- from ANY
			instance_free: class
			operating_environment_not_void: Result /= Void
	
feature -- Preconditions

	date_time_valid (s: STRING_8; code_string: STRING_8): BOOLEAN
			-- Is the code_string enough precise
			-- To create an instance of type DATE_TIME
			-- And does the string s correspond to code_string?
			-- (from DATE_TIME_VALIDITY_CHECKER)
		require -- from DATE_TIME_VALIDITY_CHECKER
			s_exists: s /= Void
			code_exists: code_string /= Void

	date_time_valid_with_base (s: STRING_8; code_string: STRING_8; base: INTEGER_32): BOOLEAN
			-- Is the code_string enough precise
			-- To create an instance of type DATE_TIME
			-- And does the string s correspond to code_string?
			-- Use base century base.
			-- (from DATE_TIME_VALIDITY_CHECKER)
		require -- from DATE_TIME_VALIDITY_CHECKER
			s_exists: s /= Void
			code_exists: code_string /= Void
			base_valid: base > 0 and (base \\ 100 = 0)

	is_correct_date_time (y, mo, d, h, mi: INTEGER_32; s: REAL_64; twelve_hour_scale: BOOLEAN): BOOLEAN
			-- Is date-time specified by y, mo, d, h, mi, s
			-- correct?
			-- twelve_hour_scale specifies if the hour range is 1 - 12
			-- (if True) or 0 - 23 (if False).
			-- (from DATE_TIME_VALIDITY_CHECKER)
	
invariant
		-- from COMPARABLE
	irreflexive_comparison: not (Current < Current)

		-- from ANY
	reflexive_equality: standard_is_equal (Current)
	reflexive_conformance: conforms_to (Current)

		-- from DATE_TIME_MEASUREMENT
	date_exists: date /= Void
	time_exists: time /= Void

note
	copyright: "Copyright (c) 1984-2017, Eiffel Software and others"
	license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
	source: "[
		Eiffel Software
		5949 Hollister Ave., Goleta, CA 93117 USA
		Telephone 805-685-1006, Fax 805-685-6869
		Website http://www.eiffel.com
		Customer support http://support.eiffel.com
	]"

end -- class DATE_TIME

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