deferred class
	EL_EXTENDABLE_AREA [G]

feature -- Status query

	not_empty: BOOLEAN
		do
			Result := area.count > 0
		end

feature -- Measurement

	area_count: INTEGER
		do
			Result := area.count
		end

feature {NONE} -- Implementation

	big_enough (a_area: like area; additional_count: INTEGER): like area
		local
			minimal: INTEGER
		do
			if a_area.count + additional_count > a_area.capacity then
				minimal := additional_count.max (Minimal_increase)
				-- changing from `aliased_resized_area' to `resized_area' fixed the bug in My Ching
				-- where strings where corrupted in test `ENCRYPTED_128_BIT_READING_LIST_TEST_SET'
				Result := a_area.resized_area (a_area.count + (a_area.capacity // 2).max (minimal))
			else
				Result := a_area
			end
		end

	set_if_changed (current_area, a_area: like area)
		do
			if current_area /= a_area then
				set_area (a_area)
			end
		end

feature {NONE} -- Deferred

	area: SPECIAL [G]
		deferred
		end

	new_filled_area (item: G; n: INTEGER): SPECIAL [G]
		deferred
		end

	set_area (a_area: like area)
		deferred
		end

feature {NONE} -- Constants

	Minimal_increase: INTEGER = 5
		-- Minimal number of additional items

note
	descendants: "[
			EL_EXTENDABLE_AREA* [G]
				${EL_SUBSTRING_32_BUFFER}
				${EL_COMPACT_SUBSTRINGS_32_BASE*}
					${EL_COMPACT_SUBSTRINGS_32_I*}
						${EL_COMPACT_SUBSTRINGS_32}
							${EL_COMPACT_SUBSTRINGS_32_BUFFER}
						${EL_ZSTRING_BASE*}
	]"
end