    indexing
    	description: "Durations of time"
    	legal: "See notice at end of class."
    	status: "See notice at end of class."
    	date: "$Date: 2006-01-22 18:25:44 -0800 (Sun, 22 Jan 2006) $"
    	revision: "$Revision: 56675 $"
    	access: time

    class interface
    	TIME_DURATION

    create
    	make (h, m, s: INTEGER_32)
    			-- Set hour, minute and second to `h', `m', `s' respectively.
    		ensure
    			hour_set: hour = h
    			minute_set: minute = m
    			second_set: second = s

    	make_fine (h, m: INTEGER_32; s: REAL_64)
    			-- Set `hour, minute and second to `h', `m' and truncated to
    			-- integer part of `s' respectively.
    			-- Set fractional_second to the fractional part of `s'.
    		ensure
    			hour_set: hour = h
    			minute_set: minute = m
    			fine_second_set: fine_second = s

    	make_by_seconds (s: INTEGER_32)
    			-- Set the object by the number of seconds `s'.
    		ensure
    			seconds_count_set: seconds_count = s

    	make_by_fine_seconds (s: REAL_64)
    			-- Set the object by the number of seconds `s'.
    		ensure
    			minute_large_enough: minute >= 0
    			minute_small_enough: minute < minutes_in_hour
    			second_large_enough: second >= 0
    			second_small_enough: second < seconds_in_minute
    			fine_seconds_set: dabs (fine_seconds_count - s) <= tolerance

    feature -- Access

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

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

    	generating_type: STRING_8
    			-- Name of current object's generating type
    			-- (type of which it is a direct instance)
    			-- (from ANY)

    	generator: STRING_8
    			-- Name of current object's generating class
    			-- (base class of the type of which it is a direct instance)
    			-- (from ANY)

    	hours_in_day: INTEGER_32 is 24
    			-- Number of hours in a day
    			-- (from TIME_CONSTANTS)

    	minutes_in_hour: INTEGER_32 is 60
    			-- Number of minutes in an hour
    			-- (from TIME_CONSTANTS)

    	seconds_in_day: INTEGER_32 is 86400
    			-- Number of seconds in an hour
    			-- (from TIME_CONSTANTS)

    	seconds_in_hour: INTEGER_32 is 3600
    			-- Number of seconds in an hour
    			-- (from TIME_CONSTANTS)

    	seconds_in_minute: INTEGER_32 is 60
    			-- Number of seconds in a minute
    			-- (from TIME_CONSTANTS)

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

    feature -- Comparison

    	frozen deep_equal (some: ANY; other: like arg #1): BOOLEAN
    			-- Are `some' and `other' either both void
    			-- or attached to isomorphic object structures?
    			-- (from ANY)
    		ensure -- from ANY
    			shallow_implies_deep: standard_equal (some, other) implies Result
    			both_or_none_void: (some = Void) implies (Result = (other = Void))
    			same_type: (Result and (some /= Void)) implies some.same_type (other)
    			symmetric: Result implies deep_equal (other, some)

    	frozen equal (some: ANY; other: like arg #1): BOOLEAN
    			-- Are `some' and `other' either both void or attached
    			-- to objects considered equal?
    			-- (from ANY)
    		ensure -- from ANY
    			definition: Result = (some = Void and other = Void) or else ((some /= Void and other /= Void) and then some.is_equal (other))

    	frozen standard_equal (some: ANY; other: like arg #1): BOOLEAN
    			-- Are `some' and `other' 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
    			definition: Result = (some = Void and other = Void) or else ((some /= Void and other /= Void) and then some.standard_is_equal (other))

    	frozen standard_is_equal (other: like Current): 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)

    	infix "<=" (other: like Current): BOOLEAN
    			-- Is current object less than or equal to `other'?
    			-- (from PART_COMPARABLE)
    		require -- from PART_COMPARABLE
    			other_exists: other /= Void

    	infix ">" (other: like Current): BOOLEAN
    			-- Is current object greater than `other'?
    			-- (from PART_COMPARABLE)
    		require -- from PART_COMPARABLE
    			other_exists: other /= Void

    	infix ">=" (other: like Current): BOOLEAN
    			-- Is current object greater than or equal to `other'?
    			-- (from PART_COMPARABLE)
    		require -- from PART_COMPARABLE
    			other_exists: other /= Void

    feature -- Status report

    	canonical: BOOLEAN
    			-- Is duration expressed minimally, i.e.
    			--	If duration is positive then
    			--		hour positive,
    			--		minute and second between 0 and 59,
    			--		fractional_second between 0 and 999?
    			--	If duration is negative then
    			--		hour negative,
    			--		minute and second between -59 and 0,
    			--		fractional_second between -999 and 0?

    	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_negative: BOOLEAN
    			-- Is duration negative?
    			-- (from DURATION)

    	is_positive: BOOLEAN
    			-- Is duration positive?

    	is_zero: BOOLEAN
    			-- Is duration zero?
    			-- (from DURATION)

    	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 -- Element change

    	prefix "+": like Current
    			-- Unary plus
    			-- (from DURATION)
    		ensure -- from GROUP_ELEMENT
    			result_exists: Result /= Void
    			result_definition: Result.is_equal (Current)

    	infix "-" (other: like Current): like Current
    			-- Difference with `other'
    			-- (from DURATION)
    		require -- from GROUP_ELEMENT
    			other_exists: other /= Void
    		ensure -- from GROUP_ELEMENT
    			result_exists: Result /= Void

    feature -- Conversion

    	time_modulo_day: like Current
    			-- Duration modulo duration of a day
    		ensure
    			result_smaller_than_day: Result.seconds_count < seconds_in_day
    			result_positive: Result >= zero

    	to_canonical: like Current
    			-- A new duration
    		ensure
    			result_canonical: Result.canonical

    	to_days: INTEGER_32
    			-- Total number of days equivalent to the current duration

    feature -- Duplication

    	copy (other: like Current)
    			-- Update current object using fields of object attached
    			-- to `other', so as to yield equal objects.
    			-- (from ANY)
    		require -- from ANY
    			other_not_void: other /= Void
    			type_identity: same_type (other)
    		ensure -- from ANY
    			is_equal: is_equal (other)

    	frozen deep_copy (other: like Current)
    			-- 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: like Current
    			-- New object structure recursively duplicated from Current.
    			-- (from ANY)
    		ensure -- from ANY
    			deep_equal: deep_equal (Current, Result)

    	frozen standard_copy (other: like Current)
    			-- 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: like Current
    			-- 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: like Current
    			-- New object equal to `Current'
    			-- twin calls copy; to change copying/twining semantics, redefine copy.
    			-- (from ANY)
    		ensure -- from ANY
    			twin_not_void: Result /= Void
    			is_equal: Result.is_equal (Current)

    feature -- Basic operations

    	frozen default: like Current
    			-- 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)

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

    	frozen do_nothing
    			-- Execute a null action.
    			-- (from ANY)

    	fine_second_add (s: REAL_64)
    			-- Add `s' seconds to the current time.
    			-- if `s' has decimals, fractional_second is modifed.

    	hour_add (h: INTEGER_32)
    			-- Add `h' hours to the current duration.
    		ensure
    			hour_set: hour = old hour + h

    	minute_add (m: INTEGER_32)
    			-- Add `m' minutes to the current duration.
    		ensure
    			minute_set: minute = old minute + m

    	second_add (s: INTEGER_32)
    			-- Add `s' seconds to the current duration.
    		ensure
    			second_set: second = old second + s

    	infix "+" (other: like Current): like Current
    			-- Sum with `other'
    		require -- from GROUP_ELEMENT
    			other_exists: other /= Void
    		ensure -- from GROUP_ELEMENT
    			result_exists: Result /= Void
    			commutative: Result.is_equal (other + Current)

    	prefix "-": like Current
    			-- Unary minus
    		ensure -- from GROUP_ELEMENT
    			result_exists: Result /= Void
    			result_definition: (Result + Current).is_equal (zero)

    feature -- Access

    	fine_seconds_count: REAL_64
    			-- Number of seconds and fractionals of seconds of current duration

    	seconds_count: INTEGER_32
    			-- Total number of seconds of current duration
    		ensure
    			same_count: Result = fine_seconds_count.truncated_to_integer

    	zero: TIME_DURATION
    			-- Neutral element for "+" and "-"
    		ensure -- from GROUP_ELEMENT
    			result_exists: Result /= Void

    feature -- Attributes

    	fine_second: REAL_64

    	fractional_second: REAL_64

    	hour: INTEGER_32

    	minute: INTEGER_32

    	second: INTEGER_32

    feature -- Comparaison

    	is_equal (other: like Current): BOOLEAN
    			-- Is the current duration equal to `other'?
    		require -- from ANY
    			other_not_void: other /= Void
    		ensure -- from ANY
    			symmetric: Result implies other.is_equal (Current)
    			consistent: standard_is_equal (other) implies Result

    	infix "<" (other: like Current): BOOLEAN
    			-- Is the current duration smaller than `other'?
    		require -- from PART_COMPARABLE
    			other_exists: other /= Void

    feature -- Element Change

    	set_fine_second (s: REAL_64)
    			-- Set fine_second to `s'.
    		require -- from TIME_MEASUREMENT
    			s_large_enough: s >= 0
    			s_small_enough: s < seconds_in_minute
    		ensure -- from TIME_MEASUREMENT
    			fine_second_set: fine_second = s

    	set_fractionals (f: REAL_64)
    			-- Set fractional_second to `f'.
    			-- `f' must have the same sign as second.
    		require -- from TIME_MEASUREMENT
    			f_large_enough: f >= 0
    			f_small_enough: f < 1
    		ensure -- from TIME_MEASUREMENT
    			second_same: second = old second

    	set_hour (h: INTEGER_32)
    			-- Set hour to `h'.
    		require -- from TIME_MEASUREMENT
    			h_large_enough: h >= 0
    			h_small_enough: h < hours_in_day
    		ensure -- from TIME_MEASUREMENT
    			hour_set: hour = h

    	set_minute (m: INTEGER_32)
    			-- Set minute to `m'.
    		require -- from TIME_MEASUREMENT
    			m_large_enough: m >= 0
    			m_small_enough: m < minutes_in_hour
    		ensure -- from TIME_MEASUREMENT
    			minute_set: minute = m

    	set_second (s: INTEGER_32)
    			-- Set second to `s'.
    			-- fractional_second is cut down to 0.
    		require -- from TIME_MEASUREMENT
    			s_large_enough: s >= 0
    			s_small_enough: s < seconds_in_minute
    		ensure -- from TIME_MEASUREMENT
    			second_set: second = s

    feature -- Initialization

    	make (h, m, s: INTEGER_32)
    			-- Set hour, minute and second to `h', `m', `s' respectively.
    		ensure
    			hour_set: hour = h
    			minute_set: minute = m
    			second_set: second = s

    	make_by_fine_seconds (s: REAL_64)
    			-- Set the object by the number of seconds `s'.
    		ensure
    			minute_large_enough: minute >= 0
    			minute_small_enough: minute < minutes_in_hour
    			second_large_enough: second >= 0
    			second_small_enough: second < seconds_in_minute
    			fine_seconds_set: dabs (fine_seconds_count - s) <= tolerance

    	make_by_seconds (s: INTEGER_32)
    			-- Set the object by the number of seconds `s'.
    		ensure
    			seconds_count_set: seconds_count = s

    	make_fine (h, m: INTEGER_32; s: REAL_64)
    			-- Set `hour, minute and second to `h', `m' and truncated to
    			-- integer part of `s' respectively.
    			-- Set fractional_second to the fractional part of `s'.
    		ensure
    			hour_set: hour = h
    			minute_set: minute = m
    			fine_second_set: fine_second = s

    feature -- Output

    	io: STD_FILES
    			-- Handle to standard file setup
    			-- (from ANY)

    	out: STRING_8
    			-- New string containing terse printable representation
    			-- of current object
    			-- Was declared in ANY as synonym of tagged_out.
    			-- (from ANY)

    	print (some: ANY)
    			-- Write terse external representation of `some'
    			-- on standard output.
    			-- (from ANY)

    	frozen tagged_out: STRING_8
    			-- New string containing terse printable representation
    			-- of current object
    			-- Was declared in ANY as synonym of out.
    			-- (from ANY)

    feature -- Platform

    	operating_environment: OPERATING_ENVIRONMENT
    			-- Objects available from the operating system
    			-- (from ANY)

    invariant
    	fractionals_large_enough: fractional_second > -1
    	fractionals_small_enough: fractional_second < 1
    	fractional_and_second_same_sign: second * fractional_second >= 0
    	equal_signs: canonical implies (hour >= 0 and minute >= 0 and fine_second >= 0) or (hour <= 0 and minute <= 0 and fine_second <= 0)

    		-- from DURATION
    	sign_correctness: is_positive xor is_negative xor is_zero

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

    		-- from GROUP_ELEMENT
    	neutral_addition: Current.is_equal (Current + zero)
    	self_subtraction: zero.is_equal (Current - Current)

    indexing
    	copyright: "Copyright (c) 1984-2006, Eiffel Software and others"
    	license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
    	source: "[
    		Eiffel Software
    		356 Storke Road, 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 TIME_DURATION