indexing
	description: "Contiguous integer intervals"
	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 $"

class interface
	INTEGER_INTERVAL

create 
	make (min_index, max_index: INTEGER_32)
			-- Set up interval to have bounds `min_index' and
			-- `max_index' (empty if `min_index' > `max_index')
		ensure
			lower_defined: lower_defined
			upper_defined: upper_defined
			set_if_non_empty: (min_index <= max_index) implies ((lower = min_index) and (upper = max_index))
			empty_if_not_in_order: (min_index > max_index) implies is_empty

feature -- Initialization

	adapt (other: INTEGER_INTERVAL)
			-- Reset to be the same interval as `other'.
		require
			other_not_void: other /= Void
		ensure
			same_lower: lower = other.lower
			same_upper: upper = other.upper
			same_lower_defined: lower_defined = other.lower_defined
			same_upper_defined: upper_defined = other.upper_defined
	
feature -- Access

	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)

	has (v: INTEGER_32): BOOLEAN
			-- Does `v' appear in interval?
			-- Was declared in INTEGER_INTERVAL as synonym of valid_index.
		require -- from  CONTAINER
			True
		ensure -- from CONTAINER
			not_found_in_empty: Result implies not is_empty
		ensure then
			iff_within_bounds: Result = ((upper_defined implies v <= upper) and (lower_defined implies v >= lower))

	item alias "[]" (i: INTEGER_32): INTEGER_32
			-- Entry at index `i', if in index interval
			-- Was declared in INTEGER_INTERVAL as synonym of infix "@".
		require -- from TABLE
			valid_key: valid_index (i)

	lower: INTEGER_32
			-- Smallest value in interval
		require
			lower_defined: lower_defined

	lower_defined: BOOLEAN
			-- Is there a lower bound?

	upper: INTEGER_32
			-- Largest value in interval
		require
			upper_defined: upper_defined

	upper_defined: BOOLEAN
			-- Is there an upper bound?

	valid_index (v: INTEGER_32): BOOLEAN
			-- Does `v' appear in interval?
			-- Was declared in INTEGER_INTERVAL as synonym of has.
		require -- from  TABLE
			True
		ensure then -- from INDEXABLE
			only_if_in_index_set: Result implies ((v >= index_set.lower) and (v <= index_set.upper))
		ensure then
			iff_within_bounds: Result = ((upper_defined implies v <= upper) and (lower_defined implies v >= lower))

	infix "@" (i: INTEGER_32): INTEGER_32
			-- Entry at index `i', if in index interval
			-- Was declared in INTEGER_INTERVAL as synonym of item.
		require -- from TABLE
			valid_key: valid_index (i)
	
feature -- Measurement

	additional_space: INTEGER_32
			-- Proposed number of additional items
			-- (from RESIZABLE)
		ensure -- from RESIZABLE
			at_least_one: Result >= 1

	capacity: INTEGER_32
			-- Maximum number of items in interval
			-- (here the same thing as count)

	count: INTEGER_32
			-- Number of items in interval
		require -- from  SET
			True
		require -- from  FINITE
			True
		ensure then
			definition: Result = upper - lower + 1

	growth_percentage: INTEGER_32 is 50
			-- Percentage by which structure will grow automatically
			-- (from RESIZABLE)

	index_set: INTEGER_INTERVAL
			-- Range of acceptable indexes
			-- (here: the interval itself)
		require -- from  INDEXABLE
			True
		ensure -- from INDEXABLE
			not_void: Result /= Void
		ensure then
			index_set_is_range: equal (Result, Current)

	minimal_increase: INTEGER_32 is 5
			-- Minimal number of additional items
			-- (from RESIZABLE)

	occurrences (v: INTEGER_32): INTEGER_32
			-- Number of times `v' appears in structure
		require -- from  BAG
			True
		ensure -- from BAG
			non_negative_occurrences: Result >= 0
		ensure then
			one_iff_in_bounds: Result = 1 implies has (v)
			zero_otherwise: Result /= 1 implies Result = 0
	
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))

	is_equal (other: like Current): BOOLEAN
			-- Is array made of the same items as `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
		ensure then
			iff_same_bounds: Result = ((lower_defined implies (other.lower_defined and lower = other.lower)) and (upper_defined implies (other.upper_defined and upper = other.upper)))

	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)
	
feature -- Status report

	all_cleared: BOOLEAN
			-- Are all items set to default values?
		ensure then
			iff_at_zero: Result = ((lower = 0) and (upper = 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

	extendible: BOOLEAN
			-- May new items be added?
			-- Answer: yes

	full: BOOLEAN
			-- Is structure full?
			-- (from BOUNDED)

	is_empty: BOOLEAN
			-- Is structure empty?
			-- (from FINITE)
		require -- from  CONTAINER
			True

	is_inserted (v: INTEGER_32): BOOLEAN
			-- Has `v' been inserted by the most recent insertion?
			-- (By default, the value returned is equivalent to calling 
			-- `has (v)'. However, descendants might be able to provide more
			-- efficient implementations.)
			-- (from COLLECTION)

	object_comparison: BOOLEAN
			-- Must search operations use equal rather than `='
			-- for comparing references? (Default: no, use `='.)
			-- (from CONTAINER)

	prunable: BOOLEAN
			-- May individual items be removed?
			-- Answer: no

	resizable: BOOLEAN
			-- May capacity be changed? (Answer: yes.)
			-- (from RESIZABLE)

	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 -- Status setting

	compare_objects
			-- Ensure that future search operations will use equal
			-- rather than `=' for comparing references.
			-- (from CONTAINER)
		require -- from CONTAINER
			changeable_comparison_criterion: changeable_comparison_criterion
		ensure -- from CONTAINER
			object_comparison

	compare_references
			-- Ensure that future search operations will use `='
			-- rather than equal for comparing references.
			-- (from CONTAINER)
		require -- from CONTAINER
			changeable_comparison_criterion: changeable_comparison_criterion
		ensure -- from CONTAINER
			reference_comparison: not object_comparison
	
feature -- Element change

	extend (v: INTEGER_32)
			-- Make sure that interval goes all the way
			-- to `v' (up or down).
			-- Was declared in INTEGER_INTERVAL as synonym of put.
		require -- from COLLECTION
			extendible: extendible
		ensure -- from COLLECTION
			item_inserted: is_inserted (v)
		ensure then -- from SET
			in_set_already: old has (v) implies (count = old count)
			added_to_set: not old has (v) implies (count = old count + 1)
		ensure then -- from BAG
			one_more_occurrence: occurrences (v) = old (occurrences (v)) + 1
		ensure then
			extended_down: lower = (old lower).min (v)
			extended_up: upper = (old upper).max (v)

	fill (other: CONTAINER [INTEGER_32])
			-- Fill with as many items of `other' as possible.
			-- The representations of `other' and current structure
			-- need not be the same.
			-- (from COLLECTION)
		require -- from COLLECTION
			other_not_void: other /= Void
			extendible: extendible

	put (v: INTEGER_32)
			-- Make sure that interval goes all the way
			-- to `v' (up or down).
			-- Was declared in INTEGER_INTERVAL as synonym of extend.
		require -- from COLLECTION
			extendible: extendible
		ensure -- from COLLECTION
			item_inserted: is_inserted (v)
		ensure then -- from SET
			in_set_already: old has (v) implies (count = old count)
			added_to_set: not old has (v) implies (count = old count + 1)
		ensure then
			extended_down: lower = (old lower).min (v)
			extended_up: upper = (old upper).max (v)
	
feature -- Removal

	changeable_comparison_criterion: BOOLEAN
			-- May object_comparison be changed?
			-- (Answer: only if set empty; otherwise insertions might
			-- introduce duplicates, destroying the set property.)
			-- (from SET)
		require -- from  CONTAINER
			True
		ensure then -- from SET
			only_on_empty: Result = is_empty

	prune_all (v: INTEGER_32)
			-- Remove all occurrences of `v'.
			-- (Reference or object equality,
			-- based on object_comparison.)
			-- (from COLLECTION)
		require -- from COLLECTION
			prunable: prunable
		ensure -- from COLLECTION
			no_more_occurrences: not has (v)

	wipe_out
			-- Remove all items.
		require -- from COLLECTION
			prunable: prunable
		ensure -- from COLLECTION
			wiped_out: is_empty
	
feature -- Resizing

	automatic_grow
			-- Change the capacity to accommodate at least
			-- Growth_percentage more items.
			-- (from RESIZABLE)
		ensure -- from RESIZABLE
			increased_capacity: capacity >= old capacity + old capacity * growth_percentage // 100

	grow (i: INTEGER_32)
			-- Ensure that capacity is at least `i'.
		require -- from  RESIZABLE
			True
		ensure -- from RESIZABLE
			new_capacity: capacity >= i
		ensure then
			no_loss_from_bottom: lower <= old lower
			no_loss_from_top: upper >= old upper

	resize (min_index, max_index: INTEGER_32)
			-- Rearrange interval to go from at most
			-- `min_index' to at least `max_index',
			-- encompassing previous bounds.

	resize_exactly (min_index, max_index: INTEGER_32)
			-- Rearrange interval to go from
			-- `min_index' to `max_index'.
	
feature -- Conversion

	as_array: ARRAY [INTEGER_32]
			-- Plain array containing interval's items
		require
			finite: upper_defined and lower_defined
		ensure
			same_lower: Result.lower = lower
			same_upper: Result.upper = upper

	linear_representation: LINEAR [INTEGER_32]
			-- Representation as a linear structure
	
feature -- Duplication

	copy (other: like Current)
			-- Reset to be the same interval as `other'.
		require -- from ANY
			other_not_void: other /= Void
			type_identity: same_type (other)
		ensure -- from ANY
			is_equal: is_equal (other)
		ensure then
			same_lower: lower = other.lower
			same_upper: upper = other.upper
			same_lower_defined: lower_defined = other.lower_defined
			same_upper_defined: upper_defined = other.upper_defined

	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)

	subinterval (start_pos, end_pos: INTEGER_32): like Current
			-- Interval made of items of current array within
			-- bounds `start_pos' and `end_pos'.

	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)
	
feature -- Iteration

	do_all (action: PROCEDURE [ANY, TUPLE [INTEGER_32]])
			-- Apply `action' to every item of current interval.
		require
			action_exists: action /= Void
			finite: upper_defined and lower_defined

	exists (condition: FUNCTION [ANY, TUPLE [INTEGER_32], BOOLEAN]): BOOLEAN
			-- Does at least one of  interval's values
			-- satisfy `condition'?
		require
			finite: upper_defined and lower_defined
			condition_not_void: condition /= Void
		ensure
			consistent_with_count: Result = (hold_count (condition) > 0)

	exists1 (condition: FUNCTION [ANY, TUPLE [INTEGER_32], BOOLEAN]): BOOLEAN
			-- Does exactly one of  interval's values
			-- satisfy `condition'?
		require
			finite: upper_defined and lower_defined
			condition_not_void: condition /= Void
		ensure
			consistent_with_count: Result = (hold_count (condition) = 1)

	for_all (condition: FUNCTION [ANY, TUPLE [INTEGER_32], BOOLEAN]): BOOLEAN
			-- Do all interval's values satisfy `condition'?
		require
			finite: upper_defined and lower_defined
			condition_not_void: condition /= Void
		ensure
			consistent_with_count: Result = (hold_count (condition) = count)

	hold_count (condition: FUNCTION [ANY, TUPLE [INTEGER_32], BOOLEAN]): INTEGER_32
			-- Number of  interval's values that
			-- satisfy `condition'
		require
			finite: upper_defined and lower_defined
			condition_not_void: condition /= Void
		ensure
			non_negative: Result >= 0
	
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
	count_definition: upper_defined and lower_defined implies count = upper - lower + 1
	index_set_is_range: equal (index_set, Current)
	not_infinite: upper_defined and lower_defined

		-- from RESIZABLE
	increase_by_at_least_one: minimal_increase >= 1

		-- from BOUNDED
	valid_count: count <= capacity
	full_definition: full = (count = capacity)

		-- from FINITE
	empty_definition: is_empty = (count = 0)
	non_negative_count: count >= 0

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

		-- from INDEXABLE
	index_set_not_void: index_set /= Void

indexing
	library: "EiffelBase: Library of reusable components for Eiffel."
	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 INTEGER_INTERVAL