note
	description: "[
		Encoding of arbitrary objects graphs between different version of
		programs containing types that might have changed and for which the
		retrieving system may know how to fix the mismatches.
	]"
	legal: "See notice at end of class."
	status: "See notice at end of class."
	date: "$Date: 2020-05-19 14:29:33 +0000 (Tue, 19 May 2020) $"
	revision: "$Revision: 104259 $"

class 
	SED_RECOVERABLE_SERIALIZER

create 
	make

feature {NONE} -- Initialization

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

	make (a_serializer: SED_READER_WRITER)
			-- Initialize current instance
			-- (from SED_SESSION_SERIALIZER)
		require -- from SED_SESSION_SERIALIZER
			a_serializer_not_void: a_serializer /= Void
			a_serializer_ready: a_serializer.is_ready_for_writing
		do
			create reflector
			create reflected_object.make (reflector)
			create object_indexes.make (1)
			traversable := Breadth_first_traversable
			serializer := a_serializer
			set_version ({SED_VERSIONS}.version_7_3)
		ensure -- from SED_SESSION_SERIALIZER
			serializer_set: serializer = a_serializer
		end
	
feature -- Access

	generating_type: TYPE [detachable SED_RECOVERABLE_SERIALIZER]
			-- 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

	root_object: detachable ANY
			-- Root object of object graph
			-- (from SED_SESSION_SERIALIZER)
		do
			Result := traversable.root_object
		end

	serializer: SED_READER_WRITER
			-- Serializer used to encode data
			-- (from SED_SESSION_SERIALIZER)
	
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: SED_RECOVERABLE_SERIALIZER): 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: SED_RECOVERABLE_SERIALIZER): BOOLEAN
			-- Is other attached to an object considered
			-- equal to current object?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		external
			"built_in"
		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: SED_RECOVERABLE_SERIALIZER): 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

	is_root_object_set: BOOLEAN
			-- Is root object of object graph set?
			-- (from SED_SESSION_SERIALIZER)

	is_traversing_mode_set: BOOLEAN
			-- Is traversing mode set?
			-- (from SED_SESSION_SERIALIZER)
		do
			Result := traversable /= Void
		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
	
feature {NONE} -- Status report

	has_reference_with_copy_semantics: BOOLEAN
			-- Does serialized data have some reference with copy semantics?
			-- If none, we optimize the serialization of references by not emitting
			-- a boolean switch each time we refer to an object.
			-- (from SED_SESSION_SERIALIZER)

	is_store_settings_enabled: BOOLEAN
			-- Are settings stored?
			-- By default not for SED_INDEPENDENT_SERIALIZER.
			-- (from SED_SESSION_SERIALIZER)
		do
			Result := True
		end
	
feature -- Element change

	set_breadth_first_traversing_mode
			-- Change graph traversing to breadth first.
			-- (from SED_SESSION_SERIALIZER)
		do
			traversable := Breadth_first_traversable
		ensure -- from SED_SESSION_SERIALIZER
			traversing_mode_set: is_traversing_mode_set
			breadth_first_mode: attached {OBJECT_GRAPH_BREADTH_FIRST_TRAVERSABLE} traversable
		end

	set_depth_first_traversing_mode
			-- Change graph traversing to depth first.
			-- (from SED_SESSION_SERIALIZER)
		do
			traversable := Depth_first_traversable
		ensure -- from SED_SESSION_SERIALIZER
			traversing_mode_set: is_traversing_mode_set
			depth_first_mode: attached {OBJECT_GRAPH_DEPTH_FIRST_TRAVERSABLE} traversable
		end

	set_root_object (an_object: like root_object)
			-- Make 'an_object' the root_object.
			-- (from SED_SESSION_SERIALIZER)
		require -- from SED_SESSION_SERIALIZER
			an_object_not_void: an_object /= Void
			traversing_mode_set: is_traversing_mode_set
		do
			traversable.set_root_object (an_object)
			is_root_object_set := True
		ensure -- from SED_SESSION_SERIALIZER
			root_object_set: root_object = an_object and is_root_object_set
			root_object_identity: root_object = traversable.root_object
		end

	set_serializer (a_serializer: like serializer)
			-- Set serializer with a_serializer.
			-- (from SED_SESSION_SERIALIZER)
		require -- from SED_SESSION_SERIALIZER
			a_serializer_not_void: a_serializer /= Void
			a_serializer_ready: a_serializer.is_ready_for_writing
		do
			serializer := a_serializer
		ensure -- from SED_SESSION_SERIALIZER
			serializer_set: serializer = a_serializer
		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: SED_RECOVERABLE_SERIALIZER)
			-- Update current object using fields of object attached
			-- to other, so as to yield equal objects.
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
			type_identity: same_type (other)
		external
			"built_in"
		ensure -- from ANY
			is_equal: Current ~ other
		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: SED_RECOVERABLE_SERIALIZER)
			-- 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: SED_RECOVERABLE_SERIALIZER
			-- 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: SED_RECOVERABLE_SERIALIZER)
			-- 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: SED_RECOVERABLE_SERIALIZER
			-- 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: SED_RECOVERABLE_SERIALIZER
			-- 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 SED_RECOVERABLE_SERIALIZER
		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

	frozen default: detachable SED_RECOVERABLE_SERIALIZER
			-- 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

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

	frozen encode
			-- Encode object graph starting with the root object.
			-- (from SED_SESSION_SERIALIZER)
		require -- from SED_SESSION_SERIALIZER
			traversing_mode_set: is_traversing_mode_set
			root_object_set: is_root_object_set
		local
			l_mem: detachable MEMORY
			l_is_collecting: BOOLEAN
			l_list_count: NATURAL_32
		do
			if not {PLATFORM}.is_dotnet then
				create l_mem
				l_is_collecting := l_mem.collecting;
				l_mem.collection_off
			end;
			traversable.set_is_skip_transient (True);
			traversable.set_is_skip_copy_semantics_reference (True);
			traversable.traverse
			if attached traversable.visited_objects as l_list and then attached traversable.visited_types as l_type_table then
				has_reference_with_copy_semantics := traversable.has_reference_with_copy_semantics
				l_list_count := l_list.count.to_natural_32
				if l_list.count > object_indexes.capacity then
					create object_indexes.make (l_list_count)
				end;
				serializer.write_compressed_natural_32 (l_list_count)
				write_header (l_list, l_type_table)
				encode_objects (l_list)
			end;
			traversable.wipe_out;
			object_indexes.wipe_out
			if l_mem /= Void and then l_is_collecting then
				l_mem.collection_on
			end
		end
	
feature {NONE} -- Implementation

	abstract_type (a_type_id: INTEGER_32): INTEGER_32
			-- Abstract type of a_type_id.
			-- (from SED_UTILITIES)
		require -- from SED_UTILITIES
			a_type_id_non_negative: a_type_id >= 0
		local
			l_spec_mapping: like Special_type_mapping
		do
			l_spec_mapping := Special_type_mapping;
			l_spec_mapping.search (a_type_id)
			if l_spec_mapping.found then
				Result := l_spec_mapping.found_item
			else
				Result := {REFLECTOR_CONSTANTS}.reference_type
			end
		end

	attributes_dynamic_types (a_type_table: HASH_TABLE [INTEGER_32, INTEGER_32]): HASH_TABLE [INTEGER_32, INTEGER_32]
			-- Table of dynamic types of attributes appearing in a_type_table.
			-- If encountering an expanded type inside one of the type of a_type_table,
			-- we add it to a_type_table.
		require
			a_type_table_not_void: a_type_table /= Void
		local
			l_reflector: like reflector
			i, nb: INTEGER_32
			l_dtype, l_obj_dtype: INTEGER_32
		do
			l_reflector := reflector
			from
				a_type_table.start
				create Result.make (500)
			until
				a_type_table.after
			loop
				from
					i := 1
					l_obj_dtype := a_type_table.item_for_iteration
					nb := l_reflector.field_count_of_type (l_obj_dtype)
					nb := nb + 1
				until
					i = nb
				loop
					if not l_reflector.is_field_transient_of_type (i, l_obj_dtype) then
						l_dtype := l_reflector.field_static_type_of_type (i, l_obj_dtype)
						if not a_type_table.has (l_dtype) then
							if l_reflector.is_field_expanded_of_type (i, l_obj_dtype) then
								a_type_table.put (l_dtype, l_dtype)
							else
								Result.put (l_dtype, l_dtype)
							end
						end
					end
					i := i + 1
				end;
				a_type_table.forth
			end
		ensure
			attributes_dynamic_types_not_void: Result /= Void
		end

	frozen encode_normal_object (a_reflected_object: REFLECTED_OBJECT)
			-- Encode normal object a_reflected_object.
			-- (from SED_SESSION_SERIALIZER)
		local
			i, nb: INTEGER_32
			l_ser: like serializer
			l_exp: REFLECTED_COPY_SEMANTICS_OBJECT
		do
			from
				l_ser := serializer
				i := 1
				nb := a_reflected_object.field_count + 1
			until
				i = nb
			loop
				if not a_reflected_object.is_field_transient (i) then
					inspect a_reflected_object.field_type (i)
					when {REFLECTOR_CONSTANTS}.boolean_type then
						l_ser.write_boolean (a_reflected_object.boolean_field (i))
					when {REFLECTOR_CONSTANTS}.character_8_type then
						l_ser.write_character_8 (a_reflected_object.character_8_field (i))
					when {REFLECTOR_CONSTANTS}.character_32_type then
						l_ser.write_character_32 (a_reflected_object.character_32_field (i))
					when {REFLECTOR_CONSTANTS}.natural_8_type then
						l_ser.write_natural_8 (a_reflected_object.natural_8_field (i))
					when {REFLECTOR_CONSTANTS}.natural_16_type then
						l_ser.write_natural_16 (a_reflected_object.natural_16_field (i))
					when {REFLECTOR_CONSTANTS}.natural_32_type then
						l_ser.write_natural_32 (a_reflected_object.natural_32_field (i))
					when {REFLECTOR_CONSTANTS}.natural_64_type then
						l_ser.write_natural_64 (a_reflected_object.natural_64_field (i))
					when {REFLECTOR_CONSTANTS}.integer_8_type then
						l_ser.write_integer_8 (a_reflected_object.integer_8_field (i))
					when {REFLECTOR_CONSTANTS}.integer_16_type then
						l_ser.write_integer_16 (a_reflected_object.integer_16_field (i))
					when {REFLECTOR_CONSTANTS}.integer_32_type then
						l_ser.write_integer_32 (a_reflected_object.integer_32_field (i))
					when {REFLECTOR_CONSTANTS}.integer_64_type then
						l_ser.write_integer_64 (a_reflected_object.integer_64_field (i))
					when {REFLECTOR_CONSTANTS}.real_32_type then
						l_ser.write_real_32 (a_reflected_object.real_32_field (i))
					when {REFLECTOR_CONSTANTS}.real_64_type then
						l_ser.write_real_64 (a_reflected_object.real_64_field (i))
					when {REFLECTOR_CONSTANTS}.pointer_type then
						l_ser.write_pointer (a_reflected_object.pointer_field (i))
					when {REFLECTOR_CONSTANTS}.reference_type then
						if has_reference_with_copy_semantics then
							if a_reflected_object.is_copy_semantics_field (i) then
								l_ser.write_boolean (True)
								l_exp := a_reflected_object.copy_semantics_field (i);
								l_ser.write_compressed_integer_32 (l_exp.dynamic_type)
								encode_normal_object (l_exp)
							else
								l_ser.write_boolean (False)
								encode_reference (a_reflected_object.reference_field (i))
							end
						else
							encode_reference (a_reflected_object.reference_field (i))
						end
					when {REFLECTOR_CONSTANTS}.expanded_type then
						l_ser.write_compressed_integer_32 (a_reflected_object.dynamic_type)
						encode_normal_object (a_reflected_object.expanded_field (i))
					else
						check
								False
						end
					end
				end
				i := i + 1
			end
		end

	frozen encode_objects (a_list: ARRAYED_LIST [separate ANY])
			-- Encode all objects referenced in a_list.
			-- (from SED_SESSION_SERIALIZER)
		require -- from SED_SESSION_SERIALIZER
			a_list_not_void: a_list /= Void
			a_list_not_empty: not a_list.is_empty
		local
			l_reflected_object: like reflected_object
			l_ser: like serializer
			l_object_indexes: like object_indexes
			l_obj: separate ANY
			i, nb: INTEGER_32
			l_area: SPECIAL [separate ANY]
			l_obj_index: NATURAL_32
		do
			l_reflected_object := reflected_object
			l_ser := serializer
			l_object_indexes := object_indexes
			from
				l_area := a_list.area
				i := 0
				nb := a_list.count
			until
				i = nb
			loop
				l_obj := l_area.item (i);
				l_reflected_object.set_object (l_obj)
				i := i + 1
				l_obj_index := l_object_indexes.index (l_obj);
				l_ser.write_compressed_natural_32 (l_obj_index)
				check
						l_obj_index = i.as_natural_32
				end
				if l_reflected_object.is_special then
					encode_special (l_obj, abstract_type (l_reflected_object.generic_dynamic_type (1)))
				elseif l_reflected_object.is_tuple then
					if attached {TUPLE} l_obj as l_tuple then
						encode_tuple_object (l_tuple)
					else
						check
							l_tuple_attached: False
						end
					end
				else
					encode_normal_object (l_reflected_object)
				end
			end
		end

	frozen encode_reference (an_object: detachable separate ANY)
			-- Encode reference to an_object.
			-- (from SED_SESSION_SERIALIZER)
		do
			if an_object /= Void then
				serializer.write_compressed_natural_32 (object_indexes.index (an_object))
			else
				serializer.write_compressed_natural_32 (0)
			end
		end

	frozen encode_special (an_object: separate ANY; a_item_type: INTEGER_32)
			-- Encode an object which is a special object.
			-- (from SED_SESSION_SERIALIZER)
		require -- from SED_SESSION_SERIALIZER
			an_object_not_void: an_object /= Void
			an_object_is_special: attached {separate SPECIAL [detachable ANY]} an_object
			a_item_type_non_negative: a_item_type >= 0
		do
			inspect a_item_type
			when {REFLECTOR_CONSTANTS}.boolean_type then
				if attached {SPECIAL [BOOLEAN]} an_object as l_spec_boolean then
					encode_special_boolean (l_spec_boolean)
				else
					check
						l_spec_boolean_not_void: False
					end
				end
			when {REFLECTOR_CONSTANTS}.character_8_type then
				if attached {SPECIAL [CHARACTER_8]} an_object as l_spec_character_8 then
					encode_special_character_8 (l_spec_character_8)
				else
					check
						l_spec_character_8_not_void: False
					end
				end
			when {REFLECTOR_CONSTANTS}.character_32_type, {REFLECTOR_CONSTANTS}.natural_32_type then
				if attached {SPECIAL [CHARACTER_32]} an_object as l_spec_character_32 then
					encode_special_character_32 (l_spec_character_32)
				elseif attached {SPECIAL [NATURAL_32]} an_object as l_spec_natural_32 then
					encode_special_natural_32 (l_spec_natural_32)
				else
					check
						l_spec_natural_32_not_void: False
					end
				end
			when {REFLECTOR_CONSTANTS}.natural_8_type then
				if attached {SPECIAL [NATURAL_8]} an_object as l_spec_natural_8 then
					encode_special_natural_8 (l_spec_natural_8)
				else
					check
						l_spec_natural_8_not_void: False
					end
				end
			when {REFLECTOR_CONSTANTS}.natural_16_type then
				if attached {SPECIAL [NATURAL_16]} an_object as l_spec_natural_16 then
					encode_special_natural_16 (l_spec_natural_16)
				else
					check
						l_spec_natural_16_not_void: False
					end
				end
			when {REFLECTOR_CONSTANTS}.natural_64_type then
				if attached {SPECIAL [NATURAL_64]} an_object as l_spec_natural_64 then
					encode_special_natural_64 (l_spec_natural_64)
				else
					check
						l_spec_natural_64_not_void: False
					end
				end
			when {REFLECTOR_CONSTANTS}.integer_8_type then
				if attached {SPECIAL [INTEGER_8]} an_object as l_spec_integer_8 then
					encode_special_integer_8 (l_spec_integer_8)
				else
					check
						l_spec_integer_8_not_void: False
					end
				end
			when {REFLECTOR_CONSTANTS}.integer_16_type then
				if attached {SPECIAL [INTEGER_16]} an_object as l_spec_integer_16 then
					encode_special_integer_16 (l_spec_integer_16)
				else
					check
						l_spec_integer_16_not_void: False
					end
				end
			when {REFLECTOR_CONSTANTS}.integer_32_type then
				if attached {SPECIAL [INTEGER_32]} an_object as l_spec_integer_32 then
					encode_special_integer_32 (l_spec_integer_32)
				else
					check
						l_spec_integer_32_not_void: False
					end
				end
			when {REFLECTOR_CONSTANTS}.integer_64_type then
				if attached {SPECIAL [INTEGER_64]} an_object as l_spec_integer_64 then
					encode_special_integer_64 (l_spec_integer_64)
				else
					check
						l_spec_integer_64_not_void: False
					end
				end
			when {REFLECTOR_CONSTANTS}.real_32_type then
				if attached {SPECIAL [REAL_32]} an_object as l_spec_real_32 then
					encode_special_real_32 (l_spec_real_32)
				else
					check
						l_spec_real_32_not_void: False
					end
				end
			when {REFLECTOR_CONSTANTS}.real_64_type then
				if attached {SPECIAL [REAL_64]} an_object as l_spec_real_64 then
					encode_special_real_64 (l_spec_real_64)
				else
					check
						l_spec_real_64_not_void: False
					end
				end
			when {REFLECTOR_CONSTANTS}.pointer_type then
				if attached {SPECIAL [POINTER]} an_object as l_spec_pointer then
					encode_special_pointer (l_spec_pointer)
				else
					check
						l_spec_pointer_not_void: False
					end
				end
			else
				check
					a_item_type_valid: a_item_type = {REFLECTOR_CONSTANTS}.reference_type
				end
				if attached {SPECIAL [detachable ANY]} an_object as l_spec_any then
					encode_special_reference (l_spec_any)
				else
					check
						l_spec_any_not_void: False
					end
				end
			end
		end

	frozen encode_special_boolean (a_spec: SPECIAL [BOOLEAN])
			-- Encode a_spec.
			-- (from SED_SESSION_SERIALIZER)
		require -- from SED_SESSION_SERIALIZER
			a_spec_not_void: a_spec /= Void
		local
			i, nb: INTEGER_32
			l_ser: like serializer
		do
			from
				nb := a_spec.count
				l_ser := serializer;
				l_ser.write_compressed_integer_32 (nb)
			until
				i = nb
			loop
				l_ser.write_boolean (a_spec.item (i))
				i := i + 1
			end
		end

	frozen encode_special_character_32 (a_spec: SPECIAL [CHARACTER_32])
			-- Encode a_spec.
			-- (from SED_SESSION_SERIALIZER)
		require -- from SED_SESSION_SERIALIZER
			a_spec_not_void: a_spec /= Void
		local
			i, nb: INTEGER_32
			l_ser: like serializer
		do
			from
				nb := a_spec.count
				l_ser := serializer;
				l_ser.write_compressed_integer_32 (nb)
			until
				i = nb
			loop
				l_ser.write_character_32 (a_spec.item (i))
				i := i + 1
			end
		end

	frozen encode_special_character_8 (a_spec: SPECIAL [CHARACTER_8])
			-- Encode a_spec.
			-- (from SED_SESSION_SERIALIZER)
		require -- from SED_SESSION_SERIALIZER
			a_spec_not_void: a_spec /= Void
		local
			i, nb: INTEGER_32
			l_ser: like serializer
		do
			from
				nb := a_spec.count
				l_ser := serializer;
				l_ser.write_compressed_integer_32 (nb)
			until
				i = nb
			loop
				l_ser.write_character_8 (a_spec.item (i))
				i := i + 1
			end
		end

	frozen encode_special_integer_16 (a_spec: SPECIAL [INTEGER_16])
			-- Encode a_spec.
			-- (from SED_SESSION_SERIALIZER)
		require -- from SED_SESSION_SERIALIZER
			a_spec_not_void: a_spec /= Void
		local
			i, nb: INTEGER_32
			l_ser: like serializer
		do
			from
				nb := a_spec.count
				l_ser := serializer;
				l_ser.write_compressed_integer_32 (nb)
			until
				i = nb
			loop
				l_ser.write_integer_16 (a_spec.item (i))
				i := i + 1
			end
		end

	frozen encode_special_integer_32 (a_spec: SPECIAL [INTEGER_32])
			-- Encode a_spec.
			-- (from SED_SESSION_SERIALIZER)
		require -- from SED_SESSION_SERIALIZER
			a_spec_not_void: a_spec /= Void
		local
			i, nb: INTEGER_32
			l_ser: like serializer
		do
			from
				nb := a_spec.count
				l_ser := serializer;
				l_ser.write_compressed_integer_32 (nb)
			until
				i = nb
			loop
				l_ser.write_integer_32 (a_spec.item (i))
				i := i + 1
			end
		end

	frozen encode_special_integer_64 (a_spec: SPECIAL [INTEGER_64])
			-- Encode a_spec.
			-- (from SED_SESSION_SERIALIZER)
		require -- from SED_SESSION_SERIALIZER
			a_spec_not_void: a_spec /= Void
		local
			i, nb: INTEGER_32
			l_ser: like serializer
		do
			from
				nb := a_spec.count
				l_ser := serializer;
				l_ser.write_compressed_integer_32 (nb)
			until
				i = nb
			loop
				l_ser.write_integer_64 (a_spec.item (i))
				i := i + 1
			end
		end

	frozen encode_special_integer_8 (a_spec: SPECIAL [INTEGER_8])
			-- Encode a_spec.
			-- (from SED_SESSION_SERIALIZER)
		require -- from SED_SESSION_SERIALIZER
			a_spec_not_void: a_spec /= Void
		local
			i, nb: INTEGER_32
			l_ser: like serializer
		do
			from
				nb := a_spec.count
				l_ser := serializer;
				l_ser.write_compressed_integer_32 (nb)
			until
				i = nb
			loop
				l_ser.write_integer_8 (a_spec.item (i))
				i := i + 1
			end
		end

	frozen encode_special_natural_16 (a_spec: SPECIAL [NATURAL_16])
			-- Encode a_spec.
			-- (from SED_SESSION_SERIALIZER)
		require -- from SED_SESSION_SERIALIZER
			a_spec_not_void: a_spec /= Void
		local
			i, nb: INTEGER_32
			l_ser: like serializer
		do
			from
				nb := a_spec.count
				l_ser := serializer;
				l_ser.write_compressed_integer_32 (nb)
			until
				i = nb
			loop
				l_ser.write_natural_16 (a_spec.item (i))
				i := i + 1
			end
		end

	frozen encode_special_natural_32 (a_spec: SPECIAL [NATURAL_32])
			-- Encode a_spec.
			-- (from SED_SESSION_SERIALIZER)
		require -- from SED_SESSION_SERIALIZER
			a_spec_not_void: a_spec /= Void
		local
			i, nb: INTEGER_32
			l_ser: like serializer
		do
			from
				nb := a_spec.count
				l_ser := serializer;
				l_ser.write_compressed_integer_32 (nb)
			until
				i = nb
			loop
				l_ser.write_natural_32 (a_spec.item (i))
				i := i + 1
			end
		end

	frozen encode_special_natural_64 (a_spec: SPECIAL [NATURAL_64])
			-- Encode a_spec.
			-- (from SED_SESSION_SERIALIZER)
		require -- from SED_SESSION_SERIALIZER
			a_spec_not_void: a_spec /= Void
		local
			i, nb: INTEGER_32
			l_ser: like serializer
		do
			from
				nb := a_spec.count
				l_ser := serializer;
				l_ser.write_compressed_integer_32 (nb)
			until
				i = nb
			loop
				l_ser.write_natural_64 (a_spec.item (i))
				i := i + 1
			end
		end

	frozen encode_special_natural_8 (a_spec: SPECIAL [NATURAL_8])
			-- Encode a_spec.
			-- (from SED_SESSION_SERIALIZER)
		require -- from SED_SESSION_SERIALIZER
			a_spec_not_void: a_spec /= Void
		local
			i, nb: INTEGER_32
			l_ser: like serializer
		do
			from
				nb := a_spec.count
				l_ser := serializer;
				l_ser.write_compressed_integer_32 (nb)
			until
				i = nb
			loop
				l_ser.write_natural_8 (a_spec.item (i))
				i := i + 1
			end
		end

	frozen encode_special_pointer (a_spec: SPECIAL [POINTER])
			-- Encode a_spec.
			-- (from SED_SESSION_SERIALIZER)
		require -- from SED_SESSION_SERIALIZER
			a_spec_not_void: a_spec /= Void
		local
			i, nb: INTEGER_32
			l_ser: like serializer
		do
			from
				nb := a_spec.count
				l_ser := serializer;
				l_ser.write_compressed_integer_32 (nb)
			until
				i = nb
			loop
				l_ser.write_pointer (a_spec.item (i))
				i := i + 1
			end
		end

	frozen encode_special_real_32 (a_spec: SPECIAL [REAL_32])
			-- Encode a_spec.
			-- (from SED_SESSION_SERIALIZER)
		require -- from SED_SESSION_SERIALIZER
			a_spec_not_void: a_spec /= Void
		local
			i, nb: INTEGER_32
			l_ser: like serializer
		do
			from
				nb := a_spec.count
				l_ser := serializer;
				l_ser.write_compressed_integer_32 (nb)
			until
				i = nb
			loop
				l_ser.write_real_32 (a_spec.item (i))
				i := i + 1
			end
		end

	frozen encode_special_real_64 (a_spec: SPECIAL [REAL_64])
			-- Encode a_spec.
			-- (from SED_SESSION_SERIALIZER)
		require -- from SED_SESSION_SERIALIZER
			a_spec_not_void: a_spec /= Void
		local
			i, nb: INTEGER_32
			l_ser: like serializer
		do
			from
				nb := a_spec.count
				l_ser := serializer;
				l_ser.write_compressed_integer_32 (nb)
			until
				i = nb
			loop
				l_ser.write_real_64 (a_spec.item (i))
				i := i + 1
			end
		end

	frozen encode_special_reference (a_spec: SPECIAL [detachable ANY])
			-- Encode a_spec.
			-- (from SED_SESSION_SERIALIZER)
		require -- from SED_SESSION_SERIALIZER
			a_spec_not_void: a_spec /= Void
		local
			i, nb: INTEGER_32
			l_reflected_object: like reflected_object
			l_exp: REFLECTED_COPY_SEMANTICS_OBJECT
			l_ser: like serializer
			l_has_copy_semantics: BOOLEAN
		do
			l_ser := serializer
			nb := a_spec.count;
			l_ser.write_compressed_integer_32 (nb)
			if version >= {SED_VERSIONS}.version_7_3 then
				from
					l_reflected_object := reflected_object;
					l_reflected_object.set_object (a_spec)
				until
					i = nb
				loop
					if l_reflected_object.is_special_copy_semantics_item (i) then
						l_has_copy_semantics := True
						i := nb - 1
					end
					i := i + 1
				end;
				l_ser.write_boolean (l_has_copy_semantics)
				if l_has_copy_semantics then
					from
						i := 0
					until
						i = nb
					loop
						if l_reflected_object.is_special_copy_semantics_item (i) then
							l_ser.write_boolean (True)
							l_exp := l_reflected_object.special_copy_semantics_item (i);
							l_ser.write_compressed_integer_32 (l_exp.dynamic_type)
							encode_normal_object (l_exp)
						else
							l_ser.write_boolean (False)
							encode_reference (a_spec.item (i))
						end
						i := i + 1
					end
				end
			end
			if not l_has_copy_semantics then
				from
					i := 0
				until
					i = nb
				loop
					encode_reference (a_spec.item (i))
					i := i + 1
				end
			end
		end

	frozen encode_tuple_object (a_tuple: TUPLE)
			-- Encode a TUPLE object.
			-- (from SED_SESSION_SERIALIZER)
		require -- from SED_SESSION_SERIALIZER
			a_tuple_not_void: a_tuple /= Void
		local
			i, nb: INTEGER_32
			l_code: NATURAL_8
			l_ser: like serializer
		do
			from
				l_ser := serializer
				i := 1
				nb := a_tuple.count + 1
			until
				i = nb
			loop
				l_code := a_tuple.item_code (i);
				l_ser.write_natural_8 (l_code)
				inspect l_code
				when {TUPLE}.boolean_code then
					l_ser.write_boolean (a_tuple.boolean_item (i))
				when {TUPLE}.character_8_code then
					l_ser.write_character_8 (a_tuple.character_8_item (i))
				when {TUPLE}.character_32_code then
					l_ser.write_character_32 (a_tuple.character_32_item (i))
				when {TUPLE}.natural_8_code then
					l_ser.write_natural_8 (a_tuple.natural_8_item (i))
				when {TUPLE}.natural_16_code then
					l_ser.write_natural_16 (a_tuple.natural_16_item (i))
				when {TUPLE}.natural_32_code then
					l_ser.write_natural_32 (a_tuple.natural_32_item (i))
				when {TUPLE}.natural_64_code then
					l_ser.write_natural_64 (a_tuple.natural_64_item (i))
				when {TUPLE}.integer_8_code then
					l_ser.write_integer_8 (a_tuple.integer_8_item (i))
				when {TUPLE}.integer_16_code then
					l_ser.write_integer_16 (a_tuple.integer_16_item (i))
				when {TUPLE}.integer_32_code then
					l_ser.write_integer_32 (a_tuple.integer_32_item (i))
				when {TUPLE}.integer_64_code then
					l_ser.write_integer_64 (a_tuple.integer_64_item (i))
				when {TUPLE}.real_32_code then
					l_ser.write_real_32 (a_tuple.real_32_item (i))
				when {TUPLE}.real_64_code then
					l_ser.write_real_64 (a_tuple.real_64_item (i))
				when {TUPLE}.pointer_code then
					l_ser.write_pointer (a_tuple.pointer_item (i))
				when {TUPLE}.reference_code then
					encode_reference (a_tuple.reference_item (i))
				else
					check
							False
					end
				end
				i := i + 1
			end
		end

	Is_special_flag: NATURAL_8 = 1
			-- (from SED_UTILITIES)

	Is_tuple_flag: NATURAL_8 = 2
			-- Various flags for storing objects
			-- (from SED_UTILITIES)

	Is_void_safe: BOOLEAN
			-- Is current system compiled in void-safe mode?
			-- (from SED_UTILITIES)
		once
			Result := {SPECIAL [ANY]} /= {SPECIAL [detachable ANY]}
		end

	Special_type_mapping: HASH_TABLE [INTEGER_32, INTEGER_32]
			-- Mapping betwwen dynamic type of SPECIAL instances
			-- to abstract element types.
			-- (from SED_UTILITIES)
		once
			create Result.make (10);
			Result.put ({REFLECTOR_CONSTANTS}.boolean_type, ({BOOLEAN}).type_id);
			Result.put ({REFLECTOR_CONSTANTS}.character_8_type, ({CHARACTER_8}).type_id);
			Result.put ({REFLECTOR_CONSTANTS}.character_32_type, ({CHARACTER_32}).type_id);
			Result.put ({REFLECTOR_CONSTANTS}.natural_8_type, ({NATURAL_8}).type_id);
			Result.put ({REFLECTOR_CONSTANTS}.natural_16_type, ({NATURAL_16}).type_id);
			Result.put ({REFLECTOR_CONSTANTS}.natural_32_type, ({NATURAL_32}).type_id);
			Result.put ({REFLECTOR_CONSTANTS}.natural_64_type, ({NATURAL_64}).type_id);
			Result.put ({REFLECTOR_CONSTANTS}.integer_8_type, ({INTEGER_8}).type_id);
			Result.put ({REFLECTOR_CONSTANTS}.integer_16_type, ({INTEGER_16}).type_id);
			Result.put ({REFLECTOR_CONSTANTS}.integer_32_type, ({INTEGER_32}).type_id);
			Result.put ({REFLECTOR_CONSTANTS}.integer_64_type, ({INTEGER_64}).type_id);
			Result.put ({REFLECTOR_CONSTANTS}.real_32_type, ({REAL_32}).type_id);
			Result.put ({REFLECTOR_CONSTANTS}.real_64_type, ({REAL_64}).type_id);
			Result.put ({REFLECTOR_CONSTANTS}.pointer_type, ({POINTER}).type_id)
		ensure -- from SED_UTILITIES
			special_type_mapping_not_void: Result /= Void
		end

	write_attributes (a_dtype: INTEGER_32)
			-- Write attribute description for type whose dynamic type id is a_dtype.
		require
			a_dtype_non_negative: a_dtype >= 0
		local
			l_reflector: like reflector
			l_ser: like serializer
			i, nb: INTEGER_32
		do
			l_reflector := reflector
			l_ser := serializer
			from
				i := 1;
				l_ser.write_compressed_natural_32 (l_reflector.persistent_field_count_of_type (a_dtype).to_natural_32)
				nb := l_reflector.field_count_of_type (a_dtype) + 1
			until
				i = nb
			loop
				if not l_reflector.is_field_transient_of_type (i, a_dtype) then
					l_ser.write_compressed_natural_32 (l_reflector.field_static_type_of_type (i, a_dtype).to_natural_32);
					l_ser.write_string_8 (l_reflector.field_name_8_of_type (i, a_dtype))
				end
				i := i + 1
			end
		end

	write_header (a_list: ARRAYED_LIST [separate ANY]; a_type_table: HASH_TABLE [INTEGER_32, INTEGER_32])
			-- Write header of storable.
		require -- from SED_SESSION_SERIALIZER
			a_list_not_void: a_list /= Void
			a_list_not_empty: not a_list.is_empty
		local
			l_attr_dtype_table: like attributes_dynamic_types
			l_dtype: INTEGER_32
			l_ser: like serializer
			l_reflector: like reflector
			l_is_independent_serializer: BOOLEAN
		do
			l_ser := serializer
			l_reflector := reflector
			write_settings
			l_is_independent_serializer := not is_store_settings_enabled
			l_attr_dtype_table := attributes_dynamic_types (a_type_table)
			from
				l_ser.write_compressed_natural_32 (a_type_table.count.to_natural_32);
				a_type_table.start
			until
				a_type_table.after
			loop
				l_dtype := a_type_table.item_for_iteration;
				l_ser.write_compressed_natural_32 (l_dtype.to_natural_32);
				l_ser.write_string_8 (l_reflector.type_name_8_of_type (l_dtype));
				a_type_table.forth
				if not l_is_independent_serializer and then version >= {SED_VERSIONS}.version_6_6 then
					if attached l_reflector.storable_version_of_type (l_dtype) as l_version and then not l_version.is_empty then
						l_ser.write_boolean (True);
						l_ser.write_string_8 (l_version)
					else
						l_ser.write_boolean (False)
					end
				end
			end
			from
				l_ser.write_compressed_natural_32 (l_attr_dtype_table.count.to_natural_32);
				l_attr_dtype_table.start
			until
				l_attr_dtype_table.after
			loop
				l_dtype := l_attr_dtype_table.item_for_iteration;
				l_ser.write_compressed_natural_32 (l_dtype.to_natural_32);
				l_ser.write_string_8 (l_reflector.type_name_8_of_type (l_dtype));
				l_attr_dtype_table.forth
			end
			from
				l_ser.write_compressed_natural_32 (a_type_table.count.to_natural_32);
				a_type_table.start
			until
				a_type_table.after
			loop
				l_dtype := a_type_table.item_for_iteration;
				l_ser.write_compressed_natural_32 (l_dtype.to_natural_32)
				write_attributes (l_dtype);
				a_type_table.forth
			end
			write_object_table (a_list)
		end

	frozen write_object_table (a_list: ARRAYED_LIST [separate ANY])
			-- Write mapping between object's reference ID in a_list with
			-- all the necessary information necessary to recreate it at a
			-- later time.
			-- (from SED_SESSION_SERIALIZER)
		require -- from SED_SESSION_SERIALIZER
			a_list_not_void: a_list /= Void
			a_list_not_empty: not a_list.is_empty
		local
			l_reflected_object: like reflected_object
			l_ser: like serializer
			l_object_indexes: like object_indexes
			i, nb: INTEGER_32
			l_obj: separate ANY
			l_area: SPECIAL [separate ANY]
		do
			l_ser := serializer;
			l_ser.write_boolean (True)
			l_reflected_object := reflected_object
			l_object_indexes := object_indexes
			from
				l_area := a_list.area
				i := 0
				nb := a_list.count
			until
				i = nb
			loop
				l_obj := l_area.item (i);
				l_reflected_object.set_object (l_obj)
				i := i + 1;
				l_ser.write_compressed_natural_32 (l_reflected_object.dynamic_type.to_natural_32);
				l_ser.write_compressed_natural_32 (l_object_indexes.index (l_obj))
				if l_reflected_object.is_special then
					l_ser.write_natural_8 (Is_special_flag);
					l_ser.write_compressed_integer_32 (abstract_type (l_reflected_object.generic_dynamic_type (1)))
					if attached {ABSTRACT_SPECIAL} l_obj as l_abstract_spec then
						l_ser.write_compressed_integer_32 (l_abstract_spec.capacity)
					else
						check
							l_abstract_spec_attached: False
						end
					end
				elseif l_reflected_object.is_tuple then
					l_ser.write_natural_8 (Is_tuple_flag)
				else
					l_ser.write_natural_8 (0)
				end
			end
		end

	frozen write_settings
			-- (from SED_SESSION_SERIALIZER)
		do
			if is_store_settings_enabled then
				serializer.write_compressed_natural_32 (version);
				serializer.write_boolean (has_reference_with_copy_semantics)
			end
		end
	
feature {NONE} -- Implementation: Access

	Breadth_first_traversable: OBJECT_GRAPH_BREADTH_FIRST_TRAVERSABLE
			-- Return an instance of OBJECT_GRAPH_BREADTH_FIRST_TRAVERSABLE.
			-- (from SED_SESSION_SERIALIZER)
		once
			Result := create {OBJECT_GRAPH_BREADTH_FIRST_TRAVERSABLE}
		end

	Depth_first_traversable: OBJECT_GRAPH_DEPTH_FIRST_TRAVERSABLE
			-- Return an instance of OBJECT_GRAPH_DEPTH_FIRST_TRAVERSABLE.
			-- (from SED_SESSION_SERIALIZER)
		once
			Result := create {OBJECT_GRAPH_DEPTH_FIRST_TRAVERSABLE}
		end

	object_indexes: SED_OBJECTS_TABLE
			-- Mapping between object and their associated index.
			-- (from SED_SESSION_SERIALIZER)

	reflected_object: REFLECTED_REFERENCE_OBJECT
			-- Facility to inspect object.
			-- (from SED_SESSION_SERIALIZER)

	reflector: REFLECTOR
			-- Facilities to inspect.
			-- (from SED_SESSION_SERIALIZER)

	traversable: OBJECT_GRAPH_TRAVERSABLE
			-- Object used for traversing object graph
			-- (from SED_SESSION_SERIALIZER)

	version: NATURAL_32
			-- Internal version of the format (See SED_VERSIONS for possible values).
			-- (from SED_SESSION_SERIALIZER)
	
feature {NONE} -- Implementation: Setting

	set_version (v: like version)
			-- Set version with v.
			-- (from SED_SESSION_SERIALIZER)
		do
			version := v
		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 SED_SESSION_SERIALIZER
	reflector_not_void: reflector /= Void
	reflected_object_not_void: reflected_object /= Void
	traversable_not_void: traversable /= Void
	serializer_not_void: serializer /= Void
	object_indexes_not_void: object_indexes /= Void

		-- from ANY
	reflexive_equality: standard_is_equal (Current)
	reflexive_conformance: conforms_to (Current)

note
	library: "EiffelBase: Library of reusable components for Eiffel."
	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 SED_RECOVERABLE_SERIALIZER

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