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