note
	description: "A common ancestor for any image library classes"
	author: "Louis Marchand"
	date: "Thu, 02 Apr 2015 03:46:04 +0000"
	revision: "2.0"

deferred class 
	IMG_ANY

feature {NONE} -- Initialization

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

	generating_type: TYPE [detachable IMG_ANY]
			-- 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

	has_error: BOOLEAN
			-- Is the library has generate an error
			-- (from GAME_ERROR_MANAGER)
	
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: IMG_ANY): 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: IMG_ANY): 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: IMG_ANY): 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
	
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: IMG_ANY)
			-- 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: IMG_ANY)
			-- 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: IMG_ANY
			-- 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: IMG_ANY)
			-- 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: IMG_ANY
			-- 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: IMG_ANY
			-- 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 IMG_ANY
		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 IMG_ANY
			-- 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 {NONE} -- Implementation

	clear_error
			-- Remove error pending in Current
		require -- from  GAME_ERROR_MANAGER
			True
		do
			has_error := False
		ensure -- from GAME_ERROR_MANAGER
			no_error: not has_error
		ensure then -- from GAME_SDL_ANY
			no_error: not is_manual_error
		end

	disable_print_on_error
			-- Desactive the print_on_error functionnality.
			-- (from GAME_ERROR_MANAGER)
		do
			Print_on_error_internal.put (False)
		end

	enable_print_on_error
			-- Active the print_on_error functionnality.
			-- (from GAME_ERROR_MANAGER)
		do
			Print_on_error_internal.put (True)
		end

	is_manual_error: BOOLEAN
			-- Is the current pending error is a manual error (using manual_error as message)
			-- (from GAME_SDL_ANY)

	manage_error_boolean (a_boolean: BOOLEAN; a_message: READABLE_STRING_GENERAL)
			-- Create an error if a_boolean is false.
			-- If there is an error, append a_message to the error message
			-- on the SDL2 library
			-- (from GAME_SDL_ANY)
		do
			if not a_boolean then
				if Print_on_error_internal.item then
					Io.Error.put_string (a_message.to_string_8 + "%N");
					Io.Error.put_string (last_error.to_string_8 + "%N")
				end
				has_error := True
			end
		ensure -- from GAME_SDL_ANY
				not a_boolean implies has_error
		end

	manage_error_code (a_error_code: INTEGER_32; a_message: READABLE_STRING_GENERAL)
			-- If needed create an error depending of the error code a_code.
			-- If there is an error, append a_message to the error message
			-- on the SDL2 library
			-- (from GAME_SDL_ANY)
		do
			if a_error_code < 0 then
				if Print_on_error_internal.item then
					Io.Error.put_string (a_message.to_string_8 + "%N");
					Io.Error.put_string (last_error.to_string_8 + "%N")
				end
				has_error := True
			end
		end

	manage_error_pointer (a_pointer: POINTER; a_message: READABLE_STRING_GENERAL)
			-- Create an error if a_pointer is not valid.
			-- If there is an error, append a_message to the error message
			-- on the SDL2 library
			-- (from GAME_SDL_ANY)
		do
			if a_pointer.is_default_pointer then
				if Print_on_error_internal.item then
					Io.Error.put_string (a_message.to_string_8 + "%N");
					Io.Error.put_string (last_error.to_string_8 + "%N")
				end
				has_error := True
			end
		ensure -- from GAME_SDL_ANY
				a_pointer.is_default_pointer implies has_error
		end

	manual_error: detachable READABLE_STRING_GENERAL
			-- The specific message for the last error
			-- (from GAME_ERROR_MANAGER)

	print_on_error: BOOLEAN
			-- When an error occured, the library will print
			-- informations about the error on the error console
			-- output (default is True).
			-- (from GAME_ERROR_MANAGER)
		do
			Result := Print_on_error_internal.item
		end

	Print_on_error_internal: CELL [BOOLEAN]
			-- True when an error occured,
			-- The library will print it right away.
			-- (from GAME_ERROR_MANAGER)
		once ("PROCESS")
			create Result.put (True)
		end

	put_manual_error (a_general_message, a_specific_error: READABLE_STRING_GENERAL)
			-- Create an error using a_general_error for the debug information
			-- and a_specific_error for the lasting information
			-- (from GAME_SDL_ANY)
		do
			is_manual_error := True
			Precursor {GAME_ERROR_MANAGER} (a_general_message, a_specific_error)
		ensure -- from GAME_ERROR_MANAGER
				has_error
		end

	set_print_on_error (a_value: BOOLEAN)
			-- Assign to print_on_error the value of a_value
			-- (from GAME_ERROR_MANAGER)
		do
			if a_value then
				enable_print_on_error
			else
				disable_print_on_error
			end
		ensure -- from GAME_ERROR_MANAGER
			is_assign: print_on_error ~ a_value
		end
	
feature -- Implementation

	last_error: READABLE_STRING_GENERAL
			-- The last error generate by the library
		require -- from  GAME_ERROR_MANAGER
			True
		local
			l_string: C_STRING
		do
			if is_manual_error then
				Result := Precursor
			else
				create l_string.make_by_pointer ({IMG_SDL_IMAGE_EXTERNAL}.img_geterror)
				Result := l_string.string
			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)

end -- class IMG_ANY

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