indexing
	description: "Two-dimensional arrays"
	legal: "See notice at end of class."
	status: "See notice at end of class."
	names: array2, matrix, table
	representation: array
	access: index, row_and_column, membership
	size: resizable
	contents: generic
	date: "$Date: 2006-01-22 18:25:44 -0800 (Sun, 22 Jan 2006) $"
	revision: "$Revision: 56675 $"

class interface
	ARRAY2 [G]

create 
	make (nb_rows, nb_columns: INTEGER_32)
			-- Create a two dimensional array which has `nb_rows'
			-- rows and `nb_columns' columns,
			-- with lower bounds starting at 1.
		require
			not_flat: nb_rows > 0
			not_thin: nb_columns > 0
		ensure
			new_count: count = height * width

feature -- Initialization

	initialize (v: G)
			-- Make each entry have value `v'.

	make (nb_rows, nb_columns: INTEGER_32)
			-- Create a two dimensional array which has `nb_rows'
			-- rows and `nb_columns' columns,
			-- with lower bounds starting at 1.
		require
			not_flat: nb_rows > 0
			not_thin: nb_columns > 0
		ensure
			new_count: count = height * width

	make_from_array (a: ARRAY [G])
			-- Initialize from the items of `a'.
			-- (Useful in proper descendants of class `ARRAY',
			-- to initialize an array-like object from a manifest array.)
			-- (from ARRAY)
		require -- from ARRAY
			array_exists: a /= Void

	make_from_cil (na: NATIVE_ARRAY [like array_item])
			-- Initialize array from `na'.
			-- (from ARRAY)
		require -- from ARRAY
			is_dotnet: {PLATFORM}.is_dotnet
			na_not_void: na /= Void
	
feature -- Access

	entry (i: INTEGER_32): G
			-- Entry at index `i', if in index interval
			-- (from ARRAY)
		require -- from ARRAY
			valid_key: valid_index (i)

	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: G): BOOLEAN
			-- Does `v' appear in array?
			-- (Reference or object equality,
			-- based on object_comparison.)
			-- (from ARRAY)
		ensure -- from CONTAINER
			not_found_in_empty: Result implies not is_empty

	item alias "[]" (row, column: INTEGER_32): G
			-- Entry at coordinates (`row', `column')
		require
			valid_row: (1 <= row) and (row <= height)
			valid_column: (1 <= column) and (column <= width)

	infix "@" (i: INTEGER_32): G assign put
			-- Entry at index `i', if in index interval
			-- Was declared in ARRAY as synonym of item.
			-- (from ARRAY)
		require -- from TABLE
			valid_key: valid_index (i)
		require -- from TO_SPECIAL
			valid_index: valid_index (i)
	
feature {ANY} -- Access

	area: SPECIAL [G]
			-- Special data zone
			-- (from TO_SPECIAL)
	
feature -- Measurement

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

	capacity: INTEGER_32
			-- Number of available indices
			-- Was declared in ARRAY as synonym of count.
			-- (from ARRAY)
		require -- from  BOUNDED
			True
		ensure then -- from ARRAY
			consistent_with_bounds: Result = upper - lower + 1

	count: INTEGER_32
			-- Number of available indices
			-- Was declared in ARRAY as synonym of capacity.
			-- (from ARRAY)
		require -- from  FINITE
			True
		ensure then -- from ARRAY
			consistent_with_bounds: Result = upper - lower + 1

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

	height: INTEGER_32
			-- Number of rows

	index_set: INTEGER_INTERVAL
			-- Range of acceptable indexes
			-- (from ARRAY)
		require -- from  INDEXABLE
			True
		ensure -- from INDEXABLE
			not_void: Result /= Void
		ensure then -- from ARRAY
			same_count: Result.count = count
			same_bounds: ((Result.lower = lower) and (Result.upper = upper))

	lower: INTEGER_32
			-- Minimum index
			-- (from ARRAY)

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

	occurrences (v: G): INTEGER_32
			-- Number of times `v' appears in structure
			-- (from ARRAY)
		ensure -- from BAG
			non_negative_occurrences: Result >= 0

	upper: INTEGER_32
			-- Maximum index
			-- (from ARRAY)

	width: INTEGER_32
			-- Number of columns
	
feature {ANY} -- Comparison

	is_equal (other: like Current): BOOLEAN
			-- Is array made of the same items as `other'?
			-- (from ARRAY)
		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 -- 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)
	
feature -- Status report

	all_default: BOOLEAN
			-- Are all items set to default values?
			-- (from ARRAY)
		ensure -- from ARRAY
			definition: Result = (count = 0 or else ((array_item (upper) = Void or else array_item (upper) = array_item (upper).default) and subarray (lower, upper - 1).all_default))

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

	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 items be added?
			-- (Answer: no, although array may be resized.)
			-- (from ARRAY)

	full: BOOLEAN
			-- Is structure filled to capacity? (Answer: yes)
			-- (from ARRAY)
		require -- from  BOX
			True

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

	is_inserted (v: G): 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 items be removed? (Answer: no.)
			-- (from ARRAY)

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

	same_items (other: like Current): BOOLEAN
			-- Do `other' and Current have same items?
			-- (from ARRAY)
		require -- from ARRAY
			other_not_void: other /= Void
		ensure -- from ARRAY
			definition: Result = ((count = other.count) and then (count = 0 or else (array_item (upper) = other.array_item (other.upper) and subarray (lower, upper - 1).same_items (other.subarray (other.lower, other.upper - 1)))))

	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))

	valid_index (i: INTEGER_32): BOOLEAN
			-- Is `i' within the bounds of the array?
			-- (from ARRAY)
		require -- from  TABLE
			True
		require -- from  TO_SPECIAL
			True
		ensure then -- from INDEXABLE
			only_if_in_index_set: Result implies ((i >= index_set.lower) and (i <= index_set.upper))

	valid_index_set: BOOLEAN
			-- (from ARRAY)
	
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

	enter (v: like array_item; i: INTEGER_32)
			-- Replace `i'-th entry, if in index interval, by `v'.
			-- (from ARRAY)
		require -- from ARRAY
			valid_key: valid_index (i)

	fill (other: CONTAINER [G])
			-- 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

	force (v: like item; row, column: INTEGER_32)
			-- Assign item `v' at coordinates (`row', `column').
			-- Resize if necessary.
		require
			row_large_enough: 1 <= row
			column_large_enough: 1 <= column

	put (v: like item; row, column: INTEGER_32)
			-- Assign item `v' at coordinates (`row', `column').
		require
			valid_row: 1 <= row and row <= height
			valid_column: 1 <= column and column <= width

	subcopy (other: ARRAY [like array_item]; start_pos, end_pos, index_pos: INTEGER_32)
			-- Copy items of `other' within bounds `start_pos' and `end_pos'
			-- to current array starting at index `index_pos'.
			-- (from ARRAY)
		require -- from ARRAY
			other_not_void: other /= Void
			valid_start_pos: other.valid_index (start_pos)
			valid_end_pos: other.valid_index (end_pos)
			valid_bounds: (start_pos <= end_pos) or (start_pos = end_pos + 1)
			valid_index_pos: valid_index (index_pos)
			enough_space: (upper - index_pos) >= (end_pos - start_pos)
	
feature -- Removal

	clear_all
			-- Reset all items to default values.
			-- (from ARRAY)
		ensure -- from ARRAY
			stable_lower: lower = old lower
			stable_upper: upper = old upper
			default_items: all_default

	discard_items
			-- Reset all items to default values with reallocation.
			-- (from ARRAY)
		ensure -- from ARRAY
			default_items: all_default

	prune_all (v: G)
			-- 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.
	
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

	conservative_resize (min_index, max_index: INTEGER_32)
			-- Rearrange array so that it can accommodate
			-- indices down to `min_index' and up to `max_index'.
			-- Do not lose any previously entered item.
			-- (from ARRAY)
		require -- from ARRAY
			good_indices: min_index <= max_index
		ensure -- from ARRAY
			no_low_lost: lower = min_index or else lower = old lower
			no_high_lost: upper = max_index or else upper = old upper

	grow (i: INTEGER_32)
			-- Change the capacity to at least `i'.
			-- (from ARRAY)
		ensure -- from RESIZABLE
			new_capacity: capacity >= i

	resize (nb_rows, nb_columns: INTEGER_32)
			-- Rearrange array so that it can accommodate
			-- `nb_rows' rows and `nb_columns' columns,
			-- without losing any previously
			-- entered items, nor changing their coordinates;
			-- do nothing if not possible.
		require
			valid_row: nb_rows >= 1
			valid_column: nb_columns >= 1
	
feature {ANY} -- Conversion

	to_c: ANY
			-- Address of actual sequence of values,
			-- for passing to external (non-Eiffel) routines.
			-- (from ARRAY)
		require -- from ARRAY
			not_is_dotnet: not {PLATFORM}.is_dotnet
	
feature -- Conversion

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

	to_cil: NATIVE_ARRAY [G]
			-- Address of actual sequence of values,
			-- for passing to external (non-Eiffel) routines.
			-- (from ARRAY)
		require -- from ARRAY
			is_dotnet: {PLATFORM}.is_dotnet
		ensure -- from ARRAY
			to_cil_not_void: Result /= Void

	to_special: SPECIAL [G]
			-- 'area'.
			-- (from ARRAY)
		ensure -- from ARRAY
			to_special_not_void: Result /= Void
	
feature {ANY} -- Duplication

	copy (other: like Current)
			-- Reinitialize by copying all the items of `other'.
			-- (This is also used by clone.)
			-- (from ARRAY)
		require -- from ANY
			other_not_void: other /= Void
			type_identity: same_type (other)
		ensure -- from ANY
			is_equal: is_equal (other)
		ensure then -- from ARRAY
			equal_areas: area.is_equal (other.area)
	
feature -- Duplication

	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)

	subarray (start_pos, end_pos: INTEGER_32): ARRAY [G]
			-- Array made of items of current array within
			-- bounds `start_pos' and `end_pos'.
			-- (from ARRAY)
		require -- from ARRAY
			valid_start_pos: valid_index (start_pos)
			valid_end_pos: end_pos <= upper
			valid_bounds: (start_pos <= end_pos) or (start_pos = end_pos + 1)
		ensure -- from ARRAY
			lower: Result.lower = start_pos
			upper: Result.upper = 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 [G]])
			-- Apply `action' to every item.
			-- Semantics not guaranteed if `action' changes the structure;
			-- in such a case, apply iterator to clone of structure instead.
			-- (from ARRAY)
		require -- from ARRAY
			action_not_void: action /= Void

	do_if (action: PROCEDURE [ANY, TUPLE [G]]; test: FUNCTION [ANY, TUPLE [G], BOOLEAN])
			-- Apply `action' to every item that satisfies `test'.
			-- Semantics not guaranteed if `action' or `test' changes the structure;
			-- in such a case, apply iterator to clone of structure instead.
			-- (from ARRAY)
		require -- from ARRAY
			action_not_void: action /= Void
			test_not_void: test /= Void

	for_all (test: FUNCTION [ANY, TUPLE [G], BOOLEAN]): BOOLEAN
			-- Is `test' true for all items?
			-- (from ARRAY)
		require -- from ARRAY
			test_not_void: test /= Void

	there_exists (test: FUNCTION [ANY, TUPLE [G], BOOLEAN]): BOOLEAN
			-- Is `test' true for at least one item?
			-- (from ARRAY)
		require -- from ARRAY
			test_not_void: test /= Void
	
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
	items_number: count = width * height

		-- from ARRAY
	area_exists: area /= Void
	consistent_size: capacity = upper - lower + 1
	non_negative_count: count >= 0
	index_set_has_same_count: valid_index_set

		-- 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 ARRAY2