indexing
	description: "Command manager which is able to retrieve the command associated to a Windows message."
	status: "See notice at end of class."
	date: "$Date$"
	revision: "$Revision$"

class interface
	WEL_COMMAND_MANAGER

create 

	make
			-- Make a command manager.

feature -- Initialization

	accommodate (n: INTEGER)
			-- Reallocate table with enough space for n items;
			-- keep all current items.
			-- (from HASH_TABLE)
		require -- from HASH_TABLE
			n >= 0
		ensure -- from HASH_TABLE
			count_not_changed: count = old count
			slot_count_same_as_count: used_slot_count = count
			breathing_space: count * 100 < capacity * initial_occupation

	make
			-- Make a command manager.

	hash_table_make (n: INTEGER)
			-- Allocate hash table for at least n items.
			-- The table will be resized automatically
			-- if more than n items are inserted.
			-- (from HASH_TABLE)
		ensure -- from HASH_TABLE
			breathing_space: n * 100 < capacity * initial_occupation
			minimum_space: minimum_capacity * 100 < capacity * initial_occupation
			more_than_minimum: capacity >= minimum_capacity
			no_status: not special_status
	
feature -- Access

	current_keys: ARRAY [INTEGER]
			-- New array containing actually used keys, from 1 to count
			-- (from HASH_TABLE)
		ensure -- from HASH_TABLE
			good_count: Result.count = count

	cursor: CURSOR
			-- Current cursor position
			-- (from HASH_TABLE)
		ensure -- from HASH_TABLE
			cursor_not_void: Result /= void

	found_item: WEL_COMMAND_EXEC
			-- Item, if any, yielded by last search operation
			-- (from HASH_TABLE)

	has (key: INTEGER): BOOLEAN
			-- Is there an item in the table with key key?
			-- (from HASH_TABLE)
		ensure then -- from HASH_TABLE
			default_case: (key = computed_default_key) implies (Result = has_default)

	has_item (v: WEL_COMMAND_EXEC): BOOLEAN
			-- Does structure include v?
			-- (Reference or object equality,
			-- based on object_comparison.)
			-- (from HASH_TABLE)
		ensure -- from CONTAINER
			not_found_in_empty: Result implies not is_empty

	item (key: INTEGER): WEL_COMMAND_EXEC
			-- Item associated with key, if present
			-- otherwise default value of type G
			-- Was declared in HASH_TABLE as synonym of @.
			-- (from HASH_TABLE)
		require -- from TABLE
			valid_key: valid_key (k)
		ensure then -- from HASH_TABLE
			default_value_if_not_present: (not (has (key))) implies (Result = computed_default_value)

	item_for_iteration: WEL_COMMAND_EXEC
			-- Element at current iteration position
			-- (from HASH_TABLE)
		require -- from HASH_TABLE
			not_off: not off

	key_for_iteration: INTEGER
			-- Key at current iteration position
			-- (from HASH_TABLE)
		require -- from HASH_TABLE
			not_off: not off
		ensure -- from HASH_TABLE
			at_iteration_position: Result = key_at (iteration_position)

	infix "@" (key: INTEGER): WEL_COMMAND_EXEC
			-- Item associated with key, if present
			-- otherwise default value of type G
			-- Was declared in HASH_TABLE as synonym of item.
			-- (from HASH_TABLE)
		require -- from TABLE
			valid_key: valid_key (k)
		ensure then -- from HASH_TABLE
			default_value_if_not_present: (not (has (key))) implies (Result = computed_default_value)
	
feature -- Measurement

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

	count: INTEGER
			-- Number of items in table
			-- (from HASH_TABLE)

	occurrences (v: WEL_COMMAND_EXEC): INTEGER
			-- Number of table items equal to v.
			-- (from HASH_TABLE)
		ensure -- from BAG
			non_negative_occurrences: Result >= 0
	
feature -- Comparison

	is_equal (other: like Current): BOOLEAN
			-- Does table contain the same information as other?
			-- (from HASH_TABLE)
		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
	
feature -- Status report

	after: BOOLEAN
			-- Is cursor past last item?
			-- Was declared in HASH_TABLE as synonym of off.
			-- (from HASH_TABLE)
		ensure -- from HASH_TABLE
			definition: Result = ((not has_default and (iteration_position >= capacity)) or (has_default and (iteration_position = (capacity + 1))))

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

	conflict: BOOLEAN
			-- Did last operation cause a conflict?
			-- (from HASH_TABLE)

	exists (message: INTEGER): BOOLEAN
			-- Does a command associated to message exist?
		require
			positive_message: message >= 0

	Extendible: BOOLEAN is True
			-- May new items be added? (Answer: yes.)
			-- (from HASH_TABLE)

	found: BOOLEAN
			-- Did last operation find the item sought?
			-- (from HASH_TABLE)

	Full: BOOLEAN is False
			-- Is structure filled to capacity? (Answer: no.)
			-- (from HASH_TABLE)

	inserted: BOOLEAN
			-- Did last operation insert an item?
			-- (from HASH_TABLE)

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

	is_inserted (v: WEL_COMMAND_EXEC): 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)

	not_found: BOOLEAN
			-- Did last operation fail to find the item sought?
			-- (from HASH_TABLE)

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

	off: BOOLEAN
			-- Is cursor past last item?
			-- Was declared in HASH_TABLE as synonym of after.
			-- (from HASH_TABLE)
		ensure -- from HASH_TABLE
			definition: Result = ((not has_default and (iteration_position >= capacity)) or (has_default and (iteration_position = (capacity + 1))))

	prunable: BOOLEAN
			-- May items be removed? (Answer: yes.)
			-- (from HASH_TABLE)

	removed: BOOLEAN
			-- Did last operation remove an item?
			-- (from HASH_TABLE)

	replaced: BOOLEAN
			-- Did last operation replace an item?
			-- (from HASH_TABLE)

	valid_cursor (c: CURSOR): BOOLEAN
			-- Can cursor be moved to position c?
			-- (from HASH_TABLE)
		require -- from HASH_TABLE
			c_not_void: c /= void

	valid_key (k: INTEGER): BOOLEAN
			-- Is k a valid key?
			-- (Answer: always yes for hash tables in this version)
			-- (from HASH_TABLE)
		ensure then -- from HASH_TABLE
			Result
	
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 -- Cursor movement

	forth
			-- Advance cursor to next occupied position,
			-- or off if no such position remains.
			-- (from HASH_TABLE)
		require -- from HASH_TABLE
			not_off: not off

	go_to (c: CURSOR)
			-- Move to position c.
			-- (from HASH_TABLE)
		require -- from HASH_TABLE
			c_not_void: c /= void
			valid_cursor: valid_cursor (c)

	search (key: INTEGER)
			-- Search for item of key key.
			-- If found, set found to true, and set
			-- found_item to item associated with key.
			-- (from HASH_TABLE)
		ensure -- from HASH_TABLE
			found_or_not_found: found or not_found
			item_if_found: found implies (found_item = content.item (position))

	start
			-- Bring cursor to first position.
			-- (from HASH_TABLE)
	
feature -- Element change

	extend (new: WEL_COMMAND_EXEC; key: INTEGER)
			-- Assuming there is no item of key key,
			-- insert new with key.
			-- Set inserted.
			--
			-- To choose between various insert/replace procedures,
			-- see instructions in the Indexing clause.
			-- (from HASH_TABLE)
		require -- from HASH_TABLE
			not_present: not has (key)
		ensure -- from HASH_TABLE
			inserted: inserted
			insertion_done: item (key) = new
			one_more: count = old count + 1
			same_slot_count_or_one_more_unless_reallocated: (used_slot_count = old used_slot_count) or (used_slot_count = old used_slot_count + 1) or (used_slot_count = count)
			default_property: has_default = ((key = computed_default_key) or (old has_default))

	fill (other: CONTAINER [WEL_COMMAND_EXEC])
			-- 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

	hash_table_force (new: WEL_COMMAND_EXEC; key: INTEGER)
			-- Update table so that new will be the item associated
			-- with key.
			-- If there was an item for that key, set found
			-- and set found_item to that item.
			-- If there was none, set not_found and set
			-- found_item to the default value.
			--
			-- To choose between various insert/replace procedures,
			-- see instructions in the Indexing clause.
			-- (from HASH_TABLE)
		require else -- from HASH_TABLE
			True
		ensure then -- from HASH_TABLE
			insertion_done: item (key) = new
			now_present: has (key)
			found_or_not_found: found or not_found
			not_found_if_was_not_present: not_found = not (old has (key))
			same_count_or_one_more: (count = old count) or (count = old count + 1)
			same_slot_count_or_one_more_unless_reallocated: (used_slot_count = old used_slot_count) or (used_slot_count = old used_slot_count + 1) or (used_slot_count = count)
			found_item_is_old_item: found implies (found_item = old (item (key)))
			default_value_if_not_found: not_found implies (found_item = computed_default_value)
			default_property: has_default = ((key = computed_default_key) or ((key /= computed_default_key) and (old has_default)))

	put (new: WEL_COMMAND_EXEC; key: INTEGER)
			-- Insert new with key if there is no other item
			-- associated with the same key.
			-- Set inserted if and only if an insertion has
			-- been made (i.e. key was not present).
			-- If so, set position to the insertion position.
			-- If not, set conflict.
			-- In either case, set found_item to the item
			-- now associated with key (previous item if
			-- there was one, new otherwise).
			--
			-- To choose between various insert/replace procedures,
			-- see instructions in the Indexing clause.
			-- (from HASH_TABLE)
		require -- from TABLE
			valid_key: valid_key (k)
		ensure then -- from HASH_TABLE
			conflict_or_inserted: conflict or inserted
			insertion_done: inserted implies item (key) = new
			now_present: inserted implies has (key)
			one_more_if_inserted: inserted implies (count = old count + 1)
			one_more_slot_if_inserted_unless_reallocated: inserted implies ((used_slot_count = old used_slot_count + 1) or (used_slot_count = count))
			unchanged_if_conflict: conflict implies (count = old count)
			same_item_if_conflict: conflict implies (item (key) = old (item (key)))
			slot_count_unchanged_if_conflict: conflict implies (used_slot_count = old used_slot_count)
			found_item_associated_with_key: found_item = item (key)
			new_item_if_inserted: inserted implies (found_item = new)
			old_item_if_conflict: conflict implies (found_item = old (item (key)))
			default_property: has_default = ((inserted and (key = computed_default_key)) or ((conflict or (key /= computed_default_key)) and (old has_default)))

	replace (new: WEL_COMMAND_EXEC; key: INTEGER)
			-- Replace item at key, if present,
			-- with new; do not change associated key.
			-- Set replaced if and only if a replacement has been made
			-- (i.e. key was present); otherwise set not_found.
			-- Set found_item to the item previously associated
			-- with key (default value if there was none).
			--
			-- To choose between various insert/replace procedures,
			-- see instructions in the Indexing clause.
			-- (from HASH_TABLE)
		ensure -- from HASH_TABLE
			replaced_or_not_found: replaced or not_found
			insertion_done: replaced implies item (key) = new
			no_change_if_not_found: not_found implies item (key) = old (item (key))
			found_item_is_old_item: found_item = old (item (key))

	replace_key (new_key: INTEGER; old_key: INTEGER)
			-- If there is an item of key old_key and no item of key
			-- new_key, replace the former's key by new_key,
			-- set replaced, and set found_item to the item
			-- previously associated with old_key.
			-- Otherwise set not_found or conflict respectively.
			-- If conflict, set found_item to the item previously
			-- associated with new_key.
			--
			-- To choose between various insert/replace procedures,
			-- see instructions in the Indexing clause.
			-- (from HASH_TABLE)
		ensure -- from HASH_TABLE
			same_count: count = old count
			same_slot_count: used_slot_count = old used_slot_count
			replaced_or_conflict_or_not_found: replaced or conflict or not_found
			old_absent: (replaced and not equal (new_key, old_key)) implies (not has (old_key))
			new_present: (replaced or conflict) = has (new_key)
			new_item: replaced implies (item (new_key) = old (item (old_key)))
			not_found_iff_no_old_key: not_found = old (not has (old_key))
			conflict_iff_already_present: conflict = old (has (new_key))
			not_inserted_if_conflict: conflict implies (item (new_key) = old (item (new_key)))
			default_property: has_default = ((new_key = computed_default_key) or ((new_key /= computed_default_key) and (old has_default)))
	
feature -- Removal

	clear_all
			-- Reset all items to default values; reset status.
			-- (from HASH_TABLE)
		require -- from COLLECTION
			prunable
		ensure -- from COLLECTION
			wiped_out: is_empty
		ensure then -- from HASH_TABLE
			position_equal_to_zero: position = 0
			count_equal_to_zero: count = 0
			used_slot_count_equal_to_zero: used_slot_count = 0
			has_default_set: not has_default
			no_status: not special_status

	hash_table_remove (key: INTEGER)
			-- Remove item associated with key, if present.
			-- Set removed if and only if an item has been
			-- removed (i.e. key was present);
			-- if so, set position to index of removed element.
			-- If not, set not_found.
			-- (from HASH_TABLE)
		ensure -- from HASH_TABLE
			removed_or_not_found: removed or not_found
			not_present: not has (key)
			one_less: found implies (count = old count - 1)
			same_slot_count: used_slot_count = old used_slot_count
			default_case: (key = computed_default_key) implies (not has_default)
			non_default_case: (key /= computed_default_key) implies (has_default = old has_default)
	
feature -- Conversion

	linear_representation: ARRAYED_LIST [WEL_COMMAND_EXEC]
			-- Representation as a linear structure
			-- (from HASH_TABLE)
		ensure then -- from HASH_TABLE
			result_exists: Result /= void
			good_count: Result.count = count
	
feature -- Duplication

	copy (other: like Current)
			-- Re-initialize from other.
			-- (from HASH_TABLE)
		require -- from ANY
			other_not_void: other /= void
			type_identity: same_type (other)
		ensure -- from ANY
			is_equal: is_equal (other)
	
feature -- Basic routines

	force (command: WEL_COMMAND_EXEC; message: INTEGER)
			-- Put command associated to message.
		require
			command_not_void: command /= void
			positive_message: message >= 0
		ensure
			exists: exists (message)

	remove (message: INTEGER)
			-- Remove the command associated to message.
		require
			positive_message: message >= 0
		ensure
			not_exists: not exists (message)
	
invariant

		-- from ANY
	reflexive_equality: standard_is_equal (Current)
	reflexive_conformance: conforms_to (Current)
		-- from HASH_TABLE
	keys_not_void: keys /= void
	content_not_void: content /= void
	keys_same_capacity_plus_one: keys.count = capacity + 1
	content_same_capacity_plus_one: content.count = capacity + 1
	deleted_same_capacity: deleted_marks.count = capacity
	keys_starts_at_zero: keys.lower = 0
	content_starts_at_zero: content.lower = 0
	deleted_starts_at_zero: deleted_marks.lower = 0
	valid_iteration_position: off or truly_occupied (iteration_position)
	control_non_negative: control >= 0
	special_status: special_status = (conflict or inserted or replaced or removed or found or not_found)
	max_occupation_meaningful: (max_occupation > 0) and (max_occupation < 100)
	initial_occupation_meaningful: (initial_occupation > 0) and (initial_occupation < 100)
	sized_generously_enough: initial_occupation < max_occupation
	count_big_enough: 0 <= count
	count_small_enough: count <= capacity
	breathing_space: count * 100 <= capacity * max_occupation
	count_no_more_than_slot_count: count <= used_slot_count
	slot_count_big_enough: 0 <= count
	slot_count_small_enough: used_slot_count <= capacity
	extra_space_non_negative: extra_space >= 0
		-- from FINITE
	empty_definition: is_empty = (count = 0)
	non_negative_count: count >= 0

end -- class WEL_COMMAND_MANAGER