note
	description: "Packed boolean strings"
	library: "Free implementation of ELKS library"
	status: "See notice at end of class."
	legal: "See notice at end of class."
	names: packed_booleans
	access: index
	representation: array
	size: fixed
	date: "$Date: 2020-02-18 09:43:52 +0000 (Tue, 18 Feb 2020) $"
	revision: "$Revision: 103939 $"

class 
	BOOL_STRING

create 
	make

feature -- Initialization

	make (n: INTEGER_32)
			-- Allocate area of n booleans.
		require
			non_negative_size: n >= 0
		do
			make_filled_area (False, n)
		ensure
			correct_allocation: count = n
			all_false: ∀ i: 1 |..| n ¦
					not item (i)
		end
	
feature {NONE} -- Initialization

	default_create
			-- Process instances of classes with no creation clause.
			-- (Default: do nothing.)
			-- (from ANY)
		do
		end

	make_empty_area (n: INTEGER_32)
			-- Creates a special object for n entries.
			-- (from TO_SPECIAL)
		require -- from TO_SPECIAL
			non_negative_argument: n >= 0
		do
			create area.make_empty (n)
		ensure -- from TO_SPECIAL
			area_allocated: area /= Void
			capacity_set: area.capacity = n
			count_set: area.count = 0
		end

	make_filled_area (a_default_value: BOOLEAN; n: INTEGER_32)
			-- Creates a special object for n entries.
			-- (from TO_SPECIAL)
		require -- from TO_SPECIAL
			non_negative_argument: n >= 0
		do
			create area.make_filled (a_default_value, n)
		ensure -- from TO_SPECIAL
			area_allocated: area /= Void
			capacity_set: area.capacity = n
			count_set: area.count = n
			area_filled: area.filled_with (a_default_value, 0, n - 1)
		end
	
feature -- Access

	area: SPECIAL [BOOLEAN]
			-- Special data zone.
			-- (from TO_SPECIAL)

	at alias "@" (i: INTEGER_32): BOOLEAN assign put
			-- Boolean at i-th position,
			-- beginning at left, 1 origin
			-- Was declared in BOOL_STRING as synonym of item.
		require -- from TO_SPECIAL
			valid_index: valid_index (i)
		do
			Result := area.item (i - 1)
		end

	generating_type: TYPE [detachable BOOL_STRING]
			-- Type of current object
			-- (type of which it is a direct instance)
			-- (from ANY)
		external
			"built_in"
		ensure -- from ANY
			generating_type_not_void: Result /= Void
		end

	generator: STRING_8
			-- Name of current object's generating class
			-- (base class of the type of which it is a direct instance)
			-- (from ANY)
		external
			"built_in"
		ensure -- from ANY
			generator_not_void: Result /= Void
			generator_not_empty: not Result.is_empty
		end

	item alias "[]" (i: INTEGER_32): BOOLEAN assign put
			-- Boolean at i-th position,
			-- beginning at left, 1 origin
			-- Was declared in BOOL_STRING as synonym of at.
		require -- from TO_SPECIAL
			valid_index: valid_index (i)
		do
			Result := area.item (i - 1)
		end
	
feature -- Measurement

	count: INTEGER_32
			-- Number of boolean in the area.
		do
			Result := area.count
		end
	
feature -- Comparison

	frozen deep_equal (a: detachable ANY; b: like arg #1): BOOLEAN
			-- Are a and b either both void
			-- or attached to isomorphic object structures?
			-- (from ANY)
		do
			if a = Void then
				Result := b = Void
			else
				Result := b /= Void and then a.is_deep_equal (b)
			end
		ensure -- from ANY
			instance_free: class
			shallow_implies_deep: standard_equal (a, b) implies Result
			both_or_none_void: (a = Void) implies (Result = (b = Void))
			same_type: (Result and (a /= Void)) implies (b /= Void and then a.same_type (b))
			symmetric: Result implies deep_equal (b, a)
		end

	frozen equal (a: detachable ANY; b: like arg #1): BOOLEAN
			-- Are a and b either both void or attached
			-- to objects considered equal?
			-- (from ANY)
		do
			if a = Void then
				Result := b = Void
			else
				Result := b /= Void and then a.is_equal (b)
			end
		ensure -- from ANY
			instance_free: class
			definition: Result = (a = Void and b = Void) or else ((a /= Void and b /= Void) and then a.is_equal (b))
		end

	frozen is_deep_equal alias "≡≡≡" (other: BOOL_STRING): BOOLEAN
			-- Are Current and other attached to isomorphic object structures?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		external
			"built_in"
		ensure -- from ANY
			shallow_implies_deep: standard_is_equal (other) implies Result
			same_type: Result implies same_type (other)
			symmetric: Result implies other.is_deep_equal (Current)
		end

	is_equal (other: like Current): BOOLEAN
			-- Is other attached to an object considered
			-- equal to current object?
		require -- from ANY
			other_not_void: other /= Void
		do
			if other = Current then
				Result := True
			else
				Result := area.same_items (other.area, 0, 0, count)
			end
		ensure -- from ANY
			symmetric: Result implies other ~ Current
			consistent: standard_is_equal (other) implies Result
		end

	frozen standard_equal (a: detachable ANY; b: like arg #1): BOOLEAN
			-- Are a and b either both void or attached to
			-- field-by-field identical objects of the same type?
			-- Always uses default object comparison criterion.
			-- (from ANY)
		do
			if a = Void then
				Result := b = Void
			else
				Result := b /= Void and then a.standard_is_equal (b)
			end
		ensure -- from ANY
			instance_free: class
			definition: Result = (a = Void and b = Void) or else ((a /= Void and b /= Void) and then a.standard_is_equal (b))
		end

	frozen standard_is_equal alias "≜" (other: BOOL_STRING): 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
		external
			"built_in"
		ensure -- from ANY
			same_type: Result implies same_type (other)
			symmetric: Result implies other.standard_is_equal (Current)
		end
	
feature -- Status report

	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
		external
			"built_in"
		end

	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
		external
			"built_in"
		ensure -- from ANY
			definition: Result = (conforms_to (other) and other.conforms_to (Current))
		end

	valid_index (i: INTEGER_32): BOOLEAN
			-- Is i within the bounds of Current?
		do
			Result := (1 <= i) and then (i <= count)
		end
	
feature -- Element change

	all_false
			-- Set all booleans to false.
		do
			area.fill_with (False, 0, count - 1)
		ensure
			all_false: ∀ i: 1 |..| count ¦
					not item (i)
		end

	all_true
			-- Set all booleans to true.
		do
			area.fill_with (True, 0, count - 1)
		ensure
			all_true: ∀ i: 1 |..| count ¦
					item (i)
		end

	put (v: like item; i: INTEGER_32)
			-- Put boolean v at i-th position
			-- beginning at left, 1 origin.
		require -- from TO_SPECIAL
			valid_index: valid_index (i)
		do
			area.put (v, i - 1)
		ensure -- from TO_SPECIAL
			inserted: item (i) = v
		end
	
feature {NONE} -- Element change

	set_area (other: like area)
			-- Make other the new area.
			-- (from TO_SPECIAL)
		do
			area := other
		ensure -- from TO_SPECIAL
			area_set: area = other
		end
	
feature -- Duplication

	frozen clone (other: detachable ANY): like other
		obsolete "Use `twin' instead. [2017-05-31]"
			-- Void if other is void; otherwise new object
			-- equal to other
			--
			-- For non-void other, clone calls copy;
			-- to change copying/cloning semantics, redefine copy.
			-- (from ANY)
		do
			if other /= Void then
				Result := other.twin
			end
		ensure -- from ANY
			instance_free: class
			equal: Result ~ other
		end

	copy (other: like Current)
			-- Update current object using fields of object attached
			-- to other, so as to yield equal objects.
		require -- from ANY
			other_not_void: other /= Void
			type_identity: same_type (other)
		do
			if other /= Current then
				standard_copy (other)
				set_area (other.area.twin)
			end
		ensure -- from ANY
			is_equal: Current ~ other
		ensure then
			not_shared_if_different: other /= Current implies area /= other.area
			equal_areas: area ~ other.area
		end

	frozen deep_clone (other: detachable ANY): like other
		obsolete "Use `deep_twin' instead. [2017-05-31]"
			-- Void if other is void: otherwise, new object structure
			-- recursively duplicated from the one attached to other
			-- (from ANY)
		do
			if other /= Void then
				Result := other.deep_twin
			end
		ensure -- from ANY
			instance_free: class
			deep_equal: deep_equal (other, Result)
		end

	frozen deep_copy (other: BOOL_STRING)
			-- Effect equivalent to that of:
			--		copy (other . deep_twin)
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		do
			copy (other.deep_twin)
		ensure -- from ANY
			deep_equal: deep_equal (Current, other)
		end

	frozen deep_twin: BOOL_STRING
			-- New object structure recursively duplicated from Current.
			-- (from ANY)
		external
			"built_in"
		ensure -- from ANY
			deep_twin_not_void: Result /= Void
			deep_equal: deep_equal (Current, Result)
		end

	frozen standard_clone (other: detachable ANY): like other
		obsolete "Use `standard_twin' instead. [2017-05-31]"
			-- Void if other is void; otherwise new object
			-- field-by-field identical to other.
			-- Always uses default copying semantics.
			-- (from ANY)
		do
			if other /= Void then
				Result := other.standard_twin
			end
		ensure -- from ANY
			instance_free: class
			equal: standard_equal (Result, other)
		end

	frozen standard_copy (other: BOOL_STRING)
			-- 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)
		external
			"built_in"
		ensure -- from ANY
			is_standard_equal: standard_is_equal (other)
		end

	frozen standard_twin: BOOL_STRING
			-- New object field-by-field identical to other.
			-- Always uses default copying semantics.
			-- (from ANY)
		external
			"built_in"
		ensure -- from ANY
			standard_twin_not_void: Result /= Void
			equal: standard_equal (Result, Current)
		end

	frozen twin: BOOL_STRING
			-- New object equal to Current
			-- twin calls copy; to change copying/twinning semantics, redefine copy.
			-- (from ANY)
		external
			"built_in"
		ensure -- from ANY
			twin_not_void: Result /= Void
			is_equal: Result ~ Current
		end
	
feature -- Basic operations

	frozen as_attached: attached BOOL_STRING
		obsolete "Remove calls to this feature. [2017-05-31]"
			-- Attached version of Current.
			-- (Can be used during transitional period to convert
			-- non-void-safe classes to void-safe ones.)
			-- (from ANY)
		do
			Result := Current
		end

	conjuncted alias "and" (other: like Current): like Current
			-- Logical and of 'Current' and other
		require
			other_not_void: other /= Void
			same_size: other.count = count
		local
			other_area, result_area: like area
			i: INTEGER_32
		do
			create Result.make (count)
			result_area := Result.area
			other_area := other.area
			from
				i := count - 1
			until
				i < 0
			loop
				result_area.put (area.item (i) and other_area.item (i), i)
				i := i - 1
			end
		end

	frozen default: detachable BOOL_STRING
			-- Default value of object's type
			-- (from ANY)
		do
		end

	frozen default_pointer: POINTER
			-- Default value of type POINTER
			-- (Avoid the need to write p.default for
			-- some p of type POINTER.)
			-- (from ANY)
		do
		ensure -- from ANY
			instance_free: class
		end

	default_rescue
			-- Process exception for routines with no Rescue clause.
			-- (Default: do nothing.)
			-- (from ANY)
		do
		end

	disjuncted alias "or" (other: like Current): like Current
			-- Logical or of 'Current' and other
		require
			other_not_void: other /= Void
			same_size: other.count = count
		local
			other_area, result_area: like area
			i: INTEGER_32
		do
			create Result.make (count)
			result_area := Result.area
			other_area := other.area
			from
				i := count - 1
			until
				i < 0
			loop
				result_area.put (area.item (i) or other_area.item (i), i)
				i := i - 1
			end
		end

	disjuncted_exclusive alias "xor" (other: like Current): like Current
			-- Logical exclusive or of 'Current' and other
		require
			other_not_void: other /= Void
			same_size: other.count = count
		local
			other_area, result_area: like area
			i: INTEGER_32
		do
			create Result.make (count)
			result_area := Result.area
			other_area := other.area
			from
				i := count - 1
			until
				i < 0
			loop
				result_area.put (area.item (i) xor other_area.item (i), i)
				i := i - 1
			end
		end

	frozen do_nothing
			-- Execute a null action.
			-- (from ANY)
		do
		ensure -- from ANY
			instance_free: class
		end

	left_shifted (n: INTEGER_32): like Current
			-- Left shifted 'Current' set, by n positions
		require
			non_negative_shift: n >= 0
		local
			result_area: like area
			shift_count: INTEGER_32
		do
			create Result.make (count)
			result_area := Result.area
			shift_count := count - n
			if shift_count > 0 then
				result_area.copy_data (area, n, 0, shift_count)
			end
		end

	negated alias "not": like Current
			-- Negation of 'Current'
		local
			result_area: like area
			i: INTEGER_32
		do
			create Result.make (count)
			result_area := Result.area
			from
				i := count - 1
			until
				i < 0
			loop
				result_area.put (not area.item (i), i)
				i := i - 1
			end
		end

	right_shifted (n: INTEGER_32): like Current
			-- Right shifted 'Current' set, by n positions
		require
			non_negative_shift: n >= 0
		local
			result_area: like area
			shift_count: INTEGER_32
		do
			create Result.make (count)
			result_area := Result.area
			shift_count := count - n
			if shift_count > 0 then
				result_area.copy_data (area, 0, n, shift_count)
			end
		end
	
feature -- Output

	Io: STD_FILES
			-- Handle to standard file setup
			-- (from ANY)
		once
			create Result;
			Result.set_output_default
		ensure -- from ANY
			instance_free: class
			io_not_void: Result /= Void
		end

	out: STRING_8
			-- New string containing terse printable representation
			-- of current object
			-- (from ANY)
		do
			Result := tagged_out
		ensure -- from ANY
			out_not_void: Result /= Void
		end

	print (o: detachable ANY)
			-- Write terse external representation of o
			-- on standard output.
			-- (from ANY)
		local
			s: READABLE_STRING_8
		do
			if attached o then
				s := o.out
				if attached {READABLE_STRING_32} s as s32 then
					Io.put_string_32 (s32)
				elseif attached {READABLE_STRING_8} s as s8 then
					Io.put_string (s8)
				else
					Io.put_string_32 (s.as_string_32)
				end
			end
		ensure -- from ANY
			instance_free: class
		end

	frozen tagged_out: STRING_8
			-- New string containing terse printable representation
			-- of current object
			-- (from ANY)
		external
			"built_in"
		ensure -- from ANY
			tagged_out_not_void: Result /= Void
		end
	
feature -- Platform

	Operating_environment: OPERATING_ENVIRONMENT
			-- Objects available from the operating system
			-- (from ANY)
		once
			create Result
		ensure -- from ANY
			instance_free: class
			operating_environment_not_void: Result /= Void
		end
	
feature {NONE} -- Retrieval

	frozen internal_correct_mismatch
			-- Called from runtime to perform a proper dynamic dispatch on correct_mismatch
			-- from MISMATCH_CORRECTOR.
			-- (from ANY)
		local
			l_msg: STRING_32
			l_exc: EXCEPTIONS
		do
			if attached {MISMATCH_CORRECTOR} Current as l_corrector then
				l_corrector.correct_mismatch
			else
				create l_msg.make_from_string ("Mismatch: ".as_string_32)
				create l_exc;
				l_msg.append (generating_type.name_32);
				l_exc.raise_retrieval_exception (l_msg)
			end
		end
	
invariant
		-- from ANY
	reflexive_equality: standard_is_equal (Current)
	reflexive_conformance: conforms_to (Current)

note
	copyright: "Copyright (c) 1984-2020, Eiffel Software and others"
	license: "Eiffel Forum License v2 (see http://www.eiffel.com/licensing/forum.txt)"
	source: "[
		Eiffel Software
		5949 Hollister Ave., 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 BOOL_STRING

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