indexing
	description: "Finite structures whose item count is subject to change"
	names: storage
	size: resizable

deferred class interface
	RESIZABLE [G]

feature -- Access

	has (v: G): BOOLEAN
			-- Does structure include v?
			-- (Reference or object equality,
			-- based on object_comparison.)
			-- (from CONTAINER)
		ensure -- from CONTAINER
			not_found_in_empty: Result implies not empty
	
feature -- Measurement

	additional_space: INTEGER
			-- Proposed number of additional items
		ensure
			at_least_one: Result >= 1

	capacity: INTEGER
			-- Number of items that may be stored
			-- (from BOUNDED)

	count: INTEGER
			-- Number of items
			-- (from FINITE)

	Growth_percentage: INTEGER is 50
			-- Percentage by which structure will grow automatically

	Minimal_increase: INTEGER is 5
			-- Minimal number of additional items
	
feature -- Status report

	changeable_comparison_criterion: BOOLEAN
			-- May object_comparison be changed?
			-- (Answer: yes by default.)
			-- (from CONTAINER)

	empty: BOOLEAN
			-- Is structure empty?
			-- (from FINITE)

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

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

	resizable: BOOLEAN
			-- May capacity be changed? (Answer: yes.)
	
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
		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
		ensure -- from CONTAINER
			reference_comparison: not object_comparison
	
feature -- Resizing

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

	grow (i: INTEGER)
			-- Ensure that capacity is at least i.
		ensure
			new_capacity: capacity >= i
	
feature -- Conversion

	linear_representation: LINEAR [G]
			-- Representation as a linear structure
			-- (from CONTAINER)
	
invariant

		-- from GENERAL
	reflexive_equality: standard_is_equal (Current);
	reflexive_conformance: conforms_to (Current);
	increase_by_at_least_one: minimal_increase >= 1;
		-- from BOUNDED
	valid_count: count <= capacity;
	full_definition: full = (count = capacity);
		-- from FINITE
	empty_definition: empty = (count = 0);
	non_negative_count: count >= 0;

end -- class RESIZABLE