note
	description: "An AUDIO_SOUND used to stream audio buffers"
	author: "Louis Marchand"
	date: "Fri, 16 Jun 2017 16:13:44 +0000"
	revision: "0.1"

class 
	AUDIO_SOUND_STREAMING

create 
	make

feature {NONE} -- Initialization

	make (a_channel_count, a_frequency, a_bits_per_sample: INTEGER_32)
			-- Initialization of Current using a_channel_count as channel_count,
			-- a_frequency as frequency and a_bits_per_sample as bits_per_sample
		require
			channel_valid: a_channel_count >= 1 and a_channel_count <= 2
			bits_per_sample_valid: a_bits_per_sample ~ 8 or a_bits_per_sample ~ 16
			frequency_valid: a_frequency > 0
		do
			sample_position := 0
			channel_count := a_channel_count
			frequency := a_frequency
			bits_per_sample := a_bits_per_sample
			is_signed := bits_per_sample ~ 16
			byte_per_buffer_sample := a_channel_count * (a_bits_per_sample // 2)
			create {LINKED_QUEUE [MANAGED_POINTER]} playing_queue.make
			is_open := True
			is_finished := False
		end
	
feature -- Access

	generating_type: TYPE [detachable AUDIO_SOUND_STREAMING]
			-- 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)

	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)

	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
	
feature --Access

	bits_per_sample: INTEGER_32
			-- Get the bit resolution of one frame of Current.

	channel_count: INTEGER_32
			-- Get the channel number of Current (1=mono, 2=stereo, etc.).

	close
			-- Do nothing
		require -- from AUDIO_SOUND
			sound_is_open: is_open
		do
			is_open := False
		ensure -- from AUDIO_SOUND
			sound_is_closed: not is_open
		end

	finish
			-- Terminate the streaming (after emptying playing_queue)
		do
			must_finish := True
		end

	frequency: INTEGER_32
			-- Get the frequency (sample rate) of Current.

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

	Is_openable: BOOLEAN = True
			-- Can Current be open

	Is_seekable: BOOLEAN = False
			-- Return true if Current support the seek functionnality.

	is_signed: BOOLEAN
			-- True if the frames in the buffer are signed.

	open
			-- Do nothing
		require -- from GAME_RESSOURCE
			ressource_is_openable: Is_openable
			ressource_is_not_open: not is_open and not has_ressource_error
		do
			is_open := True
		ensure -- from GAME_RESSOURCE
			ressource_is_open: is_open or has_ressource_error
		end

	playing_queue: QUEUE [MANAGED_POINTER]
			-- Every buffer to play.

	queue_buffer (a_buffer: MANAGED_POINTER)
			-- Add a_buffer os size a_size in the playing queue
		do
			playing_queue.extend (a_buffer)
		end

	restart
			-- Can be use to unfinished Current
		require -- from AUDIO_SOUND
			sound_is_open: is_open
		do
			is_finished := False
		end

	Sample_count: INTEGER_64 = 0
			-- Impossible to calculate

	sample_position: INTEGER_64
			-- The number of frames since the beginning of Current

	sample_seek (a_frame_number: INTEGER_64)
			-- Seek at the frame a_frame_number from the beginning of Current
		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
		do
			is_finished := False
		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: AUDIO_SOUND_STREAMING): 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: AUDIO_SOUND_STREAMING): 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: AUDIO_SOUND_STREAMING): 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: AUDIO_SOUND_STREAMING)
			-- 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: AUDIO_SOUND_STREAMING)
			-- 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: AUDIO_SOUND_STREAMING
			-- 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: AUDIO_SOUND_STREAMING)
			-- 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: AUDIO_SOUND_STREAMING
			-- 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: AUDIO_SOUND_STREAMING
			-- 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 AUDIO_SOUND_STREAMING
		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 AUDIO_SOUND_STREAMING
			-- 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 -- Implementation

	already_used_buffer: INTEGER_32
			-- The number of byte already used in the top item of playing_queue

	must_finish: BOOLEAN
			-- The finish has been called
	
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}{AUDIO_SOURCE} 

	byte_per_buffer_sample: INTEGER_32
			-- The number of byte for one frame of Current.

	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
		require -- from AUDIO_SOUND
			sound_is_open: is_open
		local
			l_space_left: INTEGER_32
		do
			l_space_left := a_max_length
			if already_used_buffer > 0 then
				if playing_queue.item.count - already_used_buffer > l_space_left then
					a_buffer.memory_copy (playing_queue.item.item + already_used_buffer, l_space_left)
					already_used_buffer := already_used_buffer + l_space_left
					l_space_left := 0
				else
					a_buffer.memory_copy (playing_queue.item.item + already_used_buffer, playing_queue.item.count - already_used_buffer)
					l_space_left := l_space_left - (playing_queue.item.count - already_used_buffer);
					playing_queue.remove
					already_used_buffer := 0
				end
			end
			from
			until
				l_space_left <= 0 or playing_queue.is_empty
			loop
				if playing_queue.item.count > l_space_left then
					a_buffer.memory_copy (playing_queue.item.item, l_space_left)
					already_used_buffer := l_space_left
					l_space_left := 0
				else
					a_buffer.memory_copy (playing_queue.item.item, playing_queue.item.count)
					l_space_left := l_space_left - playing_queue.item.count;
					playing_queue.remove
				end
			end
			last_buffer_size := a_max_length - l_space_left
			if must_finish and last_buffer_size <= 0 then
				is_finished := True
			end
		end
	
feature {AUDIO_SOURCE} 

	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
	already_used_buffer_valid: already_used_buffer > 0 implies playing_queue.count > 0

		-- 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 AUDIO_SOUND_STREAMING

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