note
	description: "Stream of data stored in non Eiffel memory"
	library: "Free implementation of ELKS library"
	status: "See notice at end of class."
	legal: "See notice at end of class."
	date: "$Date: 2012-05-24 04:13:10 +0000 (Thu, 24 May 2012) $"
	revision: "$Revision: 91981 $"

class 
	MEMORY_STREAM

create 
	make,
	make_from_pointer

feature {NONE} -- Initialization

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

	make (a_size: INTEGER_32)
			-- Initialize current with a_size bytes.
		require
			valid_size: a_size >= 0
		do
			create internal_area.make (a_size)
			is_resizable := True
		ensure
			non_void_area: area /= default_pointer
			capacity_set: capacity = a_size
			is_resizable_set: is_resizable
		end

	make_from_pointer (an_area: POINTER; a_size: INTEGER_32)
			-- Initialize Current with an_area and a_size.
			-- Current will not be resizable as we do not know
			-- who created an_area.
		require
			an_area_not_null: an_area /= default_pointer
			valid_size: a_size >= 0
		do
			create internal_area.make (a_size)
			is_resizable := False
		ensure
			non_void_area: area /= default_pointer
			capacity_set: capacity = a_size
			is_resizable_set: not is_resizable
		end
	
feature -- Access

	area: POINTER
			-- Memory area that holds data.
		do
			Result := internal_area.item
		ensure
			non_void_area: Result /= default_pointer
		end

	at alias "@" (i: INTEGER_32): INTEGER_8 assign put
			-- Entry at index i.
			-- Was declared in MEMORY_STREAM as synonym of item.
		require
			valid_index: valid_index (i)
		do
			($Result).memory_copy (area.item + i, 1)
		end

	capacity: INTEGER_32
			-- Number of bytes in Current.
		do
			Result := internal_area.count
		end

	count: INTEGER_32
			-- Number of bytes in Current.
		do
			Result := internal_area.count
		end

	generating_type: TYPE [detachable MEMORY_STREAM]
			-- 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): INTEGER_8 assign put
			-- Entry at index i.
			-- Was declared in MEMORY_STREAM as synonym of at.
		require
			valid_index: valid_index (i)
		do
			($Result).memory_copy (area.item + i, 1)
		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: MEMORY_STREAM): 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
			Result := capacity = other.capacity and then area.memory_compare (other.area, capacity)
		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: MEMORY_STREAM): 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_resizable: BOOLEAN
			-- Can Current be resized?

	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 := (0 <= i) and then (i < capacity)
		end
	
feature {NONE} -- Status report

	is_in_final_collect: BOOLEAN
			-- Is GC currently performing final collection
			-- after execution of current program?
			-- Safe to use in dispose.
			-- (from DISPOSABLE)
		external
			"C inline use %"eif_memory.h%""
		alias
			"return eif_is_in_final_collect;"
		end
	
feature -- Element change

	append (other: like Current)
			-- Append other at the end of Current.
		require
			other_not_void: other /= Void
			resizable: is_resizable
		local
			l_mp: MANAGED_POINTER
		do
			create l_mp.make_from_pointer (other.area, other.capacity);
			internal_area.resize (capacity + other.capacity);
			internal_area.append (l_mp)
		end

	force (v: INTEGER_8; i: INTEGER_32)
			-- Replace i-th entry by v.
			-- If i is out of bound, reallocate Current.
		require
			positive_index: i > 0
		do
			if not valid_index (i) then
				internal_area.resize (i + 1)
			end;
			internal_area.put_integer_8 (v, i)
		ensure
			inserted: item (i) = v
		end

	put (v: INTEGER_8; i: INTEGER_32)
			-- Replace i-th entry by v.
		require
			valid_index: valid_index (i)
		do
			internal_area.put_integer_8 (v, i)
		ensure
			inserted: item (i) = v
		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)
			-- Copy other in Current
		require -- from ANY
			other_not_void: other /= Void
			type_identity: same_type (other)
		do
			area.memory_free
			make (other.capacity);
			area.memory_copy (other.area, other.capacity)
		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: MEMORY_STREAM)
			-- 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: MEMORY_STREAM
			-- 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: MEMORY_STREAM)
			-- 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: MEMORY_STREAM
			-- 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: MEMORY_STREAM
			-- 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 MEMORY_STREAM
		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 MEMORY_STREAM
			-- 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
	
feature -- Disposal

	dispose
			-- Release area.
		do
			area.item.memory_free
		end
	
feature {NONE} -- Disposal

	internal_area: MANAGED_POINTER
	
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
	
feature -- Setting

	set_capacity (n: INTEGER_32)
			-- Was declared in MEMORY_STREAM as synonym of set_count.
		require
			valid_index: valid_index (n - 1)
		do
			internal_area.resize (n)
		ensure
			capacity_set: capacity = n
		end

	set_count (n: INTEGER_32)
			-- Was declared in MEMORY_STREAM as synonym of set_capacity.
		require
			valid_index: valid_index (n - 1)
		do
			internal_area.resize (n)
		ensure
			capacity_set: capacity = n
		end
	
invariant
	non_void_internal_area: internal_area /= Void
	area_not_null: area /= default_pointer

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

note
	copyright: "Copyright (c) 1984-2012, 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 MEMORY_STREAM

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