note
	description: "An AUDIO_SOUND file format that can contain metadatas"
	author: "Louis Marchand"
	date: "Wed, 22 Feb 2017 03:42:57 +0000"
	revision: "0.1"

deferred class 
	METADATA_AUDIO_SOUND

feature -- Access

	album: detachable READABLE_STRING_GENERAL
			-- The media that Current is from
			-- Void if no 'album' available in Current
		deferred
		end

	artist: detachable READABLE_STRING_GENERAL
			-- The name of the creator of Current
			-- Void if no 'artist' available in Current
		deferred
		end

	comment: detachable READABLE_STRING_GENERAL
			-- Anything that can be add to the definition of Current
			-- Void if no 'comment' available in Current
		deferred
		end

	date: detachable READABLE_STRING_GENERAL
			-- The creation's date of Current
			-- Void if no 'date' available in Current
		deferred
		end

	generating_type: TYPE [detachable METADATA_AUDIO_SOUND]
			-- 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

	genre: detachable READABLE_STRING_GENERAL
			-- The conventional category of Current
			-- Void if no 'genre' available in Current
		deferred
		end

	has_error: BOOLEAN
			-- Is the library has generate an error
			-- (from GAME_ERROR_MANAGER)

	has_ressource_error: BOOLEAN
			-- Has an error occured while opening Current
			-- (from GAME_RESSOURCE)

	is_open: BOOLEAN
			-- Is Current has been properly opened
			-- (from GAME_RESSOURCE)

	is_openable: BOOLEAN
			-- Can Current be open
			-- (from GAME_RESSOURCE)
		deferred
		end

	last_error: READABLE_STRING_GENERAL
			-- The last error generate by the library
			-- (from GAME_ERROR_MANAGER)
		do
			if attached message as la_message then
				Result := la_message
			else
				Result := ""
			end
		end

	open
			-- Open Current
			-- (from GAME_RESSOURCE)
		require -- from GAME_RESSOURCE
			ressource_is_openable: is_openable
			ressource_is_not_open: not is_open and not has_ressource_error
		deferred
		ensure -- from GAME_RESSOURCE
			ressource_is_open: is_open or has_ressource_error
		end

	title: detachable READABLE_STRING_GENERAL
			-- The readable identifier of Current
			-- Void if no 'title' available in Current
		deferred
		end

	track_number: INTEGER_32
			-- The number of Current in the album
			-- 0 if no 'track_number' available in Current
		deferred
		end
	
feature --Access

	bits_per_sample: INTEGER_32
			-- Get the bit resolution of one frame of Current.
			-- (from AUDIO_SOUND)
		require -- from AUDIO_SOUND
			sound_is_open: is_open
		deferred
		end

	channel_count: INTEGER_32
			-- Get the channel number of Current (1=mono, 2=stereo, etc.).
			-- (from AUDIO_SOUND)
		require -- from AUDIO_SOUND
			sound_is_open: is_open
		deferred
		end

	close
			-- Stop the management of the stream
			-- (from AUDIO_SOUND)
		require -- from AUDIO_SOUND
			sound_is_open: is_open
		deferred
		ensure -- from AUDIO_SOUND
			sound_is_closed: not is_open
		end

	frequency: INTEGER_32
			-- Get the frequency (sample rate) of Current.
			-- (from AUDIO_SOUND)
		require -- from AUDIO_SOUND
			sound_is_open: is_open
		deferred
		end

	is_finished: BOOLEAN
			-- Current has finished it's playback
			-- (from AUDIO_SOUND)

	is_seekable: BOOLEAN
			-- Return true if Current support the seek functionnality.
			-- (from AUDIO_SOUND)
		require -- from AUDIO_SOUND
			sound_is_open: is_open
		deferred
		end

	is_signed: BOOLEAN
			-- True if the frames in the buffer are signed.
			-- (from AUDIO_SOUND)
		require -- from AUDIO_SOUND
			sound_is_open: is_open
		deferred
		end

	restart
			-- Restart Current to the beginning.
			-- (from AUDIO_SOUND)
		require -- from AUDIO_SOUND
			sound_is_open: is_open
		deferred
		end

	sample_count: INTEGER_64
			-- The total number of frames in Current
			-- (from AUDIO_SOUND)
		require -- from AUDIO_SOUND
			sound_is_open: is_open
			is_seekable: is_seekable
		deferred
		end

	sample_position: INTEGER_64
			-- The number of frames since the beginning of Current
			-- (from AUDIO_SOUND)
		require -- from AUDIO_SOUND
			sound_is_open: is_open
			is_seekable: is_seekable
		deferred
		end

	sample_seek (a_frame_number: INTEGER_64)
			-- Seek at the frame a_frame_number from the beginning of Current
			-- (from AUDIO_SOUND)
		require -- from AUDIO_SOUND
			sound_is_open: is_open
			is_seekable: is_seekable
			is_seek_inside: a_frame_number >= 1 and a_frame_number <= sample_count
		deferred
		end

	time_count: INTEGER_64
			-- The total number of milliseconds in Current
			-- (from AUDIO_SOUND)
		require -- from AUDIO_SOUND
			sound_is_open: is_open
			is_seekable: is_seekable
		do
			Result := (sample_count * 1000) // frequency.to_integer_64
		end

	time_position: INTEGER_64
			-- The number of milliseconds since the beginning of Current
			-- (from AUDIO_SOUND)
		require -- from AUDIO_SOUND
			sound_is_open: is_open
			is_seekable: is_seekable
		do
			Result := ((sample_position - 1) * 1000) // frequency.to_integer_64
		end

	time_seek (a_milliseconds: INTEGER_64)
			-- Seek at a_milliseconds from the beginning of Current
			-- (from AUDIO_SOUND)
		require -- from AUDIO_SOUND
			sound_is_open: is_open
			is_seekable: is_seekable
			is_seek_inside: a_milliseconds >= 1 and a_milliseconds <= time_count
		do
			sample_seek (((a_milliseconds * frequency.to_integer_64) // 1000) + 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: METADATA_AUDIO_SOUND): 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: METADATA_AUDIO_SOUND): 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: METADATA_AUDIO_SOUND): 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: METADATA_AUDIO_SOUND)
			-- 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: METADATA_AUDIO_SOUND)
			-- 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: METADATA_AUDIO_SOUND
			-- 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: METADATA_AUDIO_SOUND)
			-- 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: METADATA_AUDIO_SOUND
			-- 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: METADATA_AUDIO_SOUND
			-- 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 METADATA_AUDIO_SOUND
		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 METADATA_AUDIO_SOUND
			-- 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
			-- (from GAME_ERROR_MANAGER)
		do
			has_error := False
		ensure -- from GAME_ERROR_MANAGER
			no_error: not has_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

	message: 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_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_ERROR_MANAGER)
		local
			l_converter: UTF_CONVERTER
		do
			message := a_specific_error
			has_error := True
			if Print_on_error_internal.item then
				if a_general_message.is_valid_as_string_8 then
					Io.Error.put_string (a_general_message.to_string_8 + "%N")
				else
					create l_converter;
					Io.Error.put_string (l_converter.string_32_to_utf_8_string_8 (a_general_message.to_string_32) + "%N")
				end
				if a_specific_error.is_valid_as_string_8 then
					Io.Error.put_string (a_specific_error.to_string_8 + "%N")
				else
					create l_converter;
					Io.Error.put_string (l_converter.string_32_to_utf_8_string_8 (a_specific_error.to_string_32) + "%N")
				end
			end
		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 {AUDIO_SOURCE} 

	byte_per_buffer_sample: INTEGER_32
			-- The number of byte for one frame of Current.
			-- (from AUDIO_SOUND)
		require -- from AUDIO_SOUND
			sound_is_open: is_open
		deferred
		end

	fill_buffer (a_buffer: POINTER; a_max_length: INTEGER_32)
			-- Fill the next data samples in a_buffer (no more than a_max_length byte)
			-- The actual number of byte placed in a_buffer will be available in last_buffer_size
			-- Warning: side effect on a_buffer
			-- (from AUDIO_SOUND)
		require -- from AUDIO_SOUND
			sound_is_open: is_open
		deferred
		end

	last_buffer_size: INTEGER_32
			-- The size of the last buffer filled by fill_buffer
			-- (from AUDIO_SOUND)
	
feature {NONE} -- Initialisation

	default_create
			-- Initialization of Current
			-- (from GAME_RESSOURCE)
		require -- from  ANY
			True
		do
			is_open := False
			has_ressource_error := False
		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 AUDIO_SOUND
	errors_valid: has_error ~ has_ressource_error

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

end -- class METADATA_AUDIO_SOUND

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