note
	description: "Tools to capture audio from a capturing audio device"
	author: "Louis Marchand"
	date: "Thu, 15 Jun 2017 19:17:55 +0000"
	revision: "0.1"

class interface
	AUDIO_CAPTURE_CONTROLLER

create {AUDIO_LIBRARY_CONTROLLER}
	make (a_device: POINTER; a_frequency, a_channel_count, a_bits_per_sample, a_buffer_count: INTEGER_32)
			-- Initialization of Current using a_device as device, a_frequency as frequency
			-- a_channel_count as channel_count and a_bits_per_sample as bits_per_sample and a_buffer_count to initialize buffer
			-- and buffer_sample_count
		require
			device_valid: not a_device.is_default_pointer
			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

feature -- Access

	bits_per_sample: INTEGER_32
			-- The bit resolution of one frame of Current (without channel count).

	buffer: MANAGED_POINTER
			-- The data that has been read by update

	buffer_sample_count: INTEGER_32
			-- The number of samples that the buffer will be able to contain (for example,
			-- a stereo 16 bits capture with a buffer count of 1024 will have the size 1024*2*2 = 5096 bytes)

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

	frequency: INTEGER_32
			-- The frequency (sample rate) of Current.

	generating_type: TYPE [detachable AUDIO_CAPTURE_CONTROLLER]
			-- Type of current object
			-- (type of which it is a direct instance)
			-- (from ANY)
		ensure -- from ANY
			generating_type_not_void: Result /= Void

	generator: STRING_8
			-- Name of current object's generating class
			-- (base class of the type of which it is a direct instance)
			-- (from ANY)
		ensure -- from ANY
			generator_not_void: Result /= Void
			generator_not_empty: not Result.is_empty

	get_sample (a_index: INTEGER_32): LIST [INTEGER_16]
			-- Get the sample at the position a_index in the buffer (start at 1).
			-- The number of value in Result represent the channel_count
			-- If bits_per_sample is 8, the values are unsigned from 0 to 255 with 128 being an ouput level of 0
			-- If bits_per_sample is 16, the values are signed from -32768 to 32767 with 0 being an ouput level of 0
		require
			index_valid: a_index >= 1 and a_index <= buffer_sample_count
		ensure
			sample_count_valid: Result.count ~ channel_count

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

	has_samples: BOOLEAN
			-- Samples has been found by the last call to update

	is_capturing: BOOLEAN
			-- Current is presently capturing sound

	is_device_closed: BOOLEAN
			-- The capturing device id closed

	last_error: READABLE_STRING_GENERAL
			-- The last error generate by the library
			-- (from AUDIO_OPENAL_ERROR_MANAGER)

	start_capture
			-- Strart the capture (use update to fill the buffer)
		require
			device_open: not is_device_closed
			not_already_started: not is_capturing
		ensure
			capture_started: not has_error implies is_capturing

	stop_capture
			-- Stop the capture
		require
			device_open: not is_device_closed
			not_already_stopped: is_capturing
		ensure
			captue_stopped: not is_capturing

	update
			-- Update a_buffer with the new value of the capture
		require
			device_open: not is_device_closed
			is_capturing: is_capturing
	
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)
		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)

	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)
		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))

	frozen is_deep_equal alias "≡≡≡" (other: AUDIO_CAPTURE_CONTROLLER): BOOLEAN
			-- Are Current and other attached to isomorphic object structures?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		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)

	is_equal (other: AUDIO_CAPTURE_CONTROLLER): BOOLEAN
			-- Is other attached to an object considered
			-- equal to current object?
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		ensure -- from ANY
			symmetric: Result implies other ~ Current
			consistent: standard_is_equal (other) implies Result

	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)
		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))

	frozen standard_is_equal alias "≜" (other: AUDIO_CAPTURE_CONTROLLER): 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
		ensure -- from ANY
			same_type: Result implies same_type (other)
			symmetric: Result implies other.standard_is_equal (Current)
	
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

	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
		ensure -- from ANY
			definition: Result = (conforms_to (other) and other.conforms_to (Current))
	
feature -- Duplication

	copy (other: AUDIO_CAPTURE_CONTROLLER)
			-- 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)
		ensure -- from ANY
			is_equal: Current ~ other

	frozen deep_copy (other: AUDIO_CAPTURE_CONTROLLER)
			-- Effect equivalent to that of:
			--		copy (other . deep_twin)
			-- (from ANY)
		require -- from ANY
			other_not_void: other /= Void
		ensure -- from ANY
			deep_equal: deep_equal (Current, other)

	frozen deep_twin: AUDIO_CAPTURE_CONTROLLER
			-- New object structure recursively duplicated from Current.
			-- (from ANY)
		ensure -- from ANY
			deep_twin_not_void: Result /= Void
			deep_equal: deep_equal (Current, Result)

	frozen standard_copy (other: AUDIO_CAPTURE_CONTROLLER)
			-- 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)
		ensure -- from ANY
			is_standard_equal: standard_is_equal (other)

	frozen standard_twin: AUDIO_CAPTURE_CONTROLLER
			-- New object field-by-field identical to other.
			-- Always uses default copying semantics.
			-- (from ANY)
		ensure -- from ANY
			standard_twin_not_void: Result /= Void
			equal: standard_equal (Result, Current)

	frozen twin: AUDIO_CAPTURE_CONTROLLER
			-- New object equal to Current
			-- twin calls copy; to change copying/twinning semantics, redefine copy.
			-- (from ANY)
		ensure -- from ANY
			twin_not_void: Result /= Void
			is_equal: Result ~ Current
	
feature -- Basic operations

	frozen default: detachable AUDIO_CAPTURE_CONTROLLER
			-- Default value of object's type
			-- (from ANY)

	frozen default_pointer: POINTER
			-- Default value of type POINTER
			-- (Avoid the need to write p.default for
			-- some p of type POINTER.)
			-- (from ANY)
		ensure -- from ANY
			instance_free: class

	default_rescue
			-- Process exception for routines with no Rescue clause.
			-- (Default: do nothing.)
			-- (from ANY)

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

	Io: STD_FILES
			-- Handle to standard file setup
			-- (from ANY)
		ensure -- from ANY
			instance_free: class
			io_not_void: Result /= Void

	out: STRING_8
			-- New string containing terse printable representation
			-- of current object
			-- (from ANY)
		ensure -- from ANY
			out_not_void: Result /= Void

	print (o: detachable ANY)
			-- Write terse external representation of o
			-- on standard output.
			-- (from ANY)
		ensure -- from ANY
			instance_free: class

	frozen tagged_out: STRING_8
			-- New string containing terse printable representation
			-- of current object
			-- (from ANY)
		ensure -- from ANY
			tagged_out_not_void: Result /= Void
	
feature -- Platform

	Operating_environment: OPERATING_ENVIRONMENT
			-- Objects available from the operating system
			-- (from ANY)
		ensure -- from ANY
			instance_free: class
			operating_environment_not_void: Result /= Void
	
invariant
	buffer_count_valid: buffer.count ~ buffer_sample_count * channel_count * (bits_per_sample // 8)

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

end -- class AUDIO_CAPTURE_CONTROLLER

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