WSJT-X/portaudio-v19/docs/portaudio_h.txt

#ifndef PORT_AUDIO_H
#define PORT_AUDIO_H

#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */

/*
 * PortAudio Portable Real-Time Audio Library
 * PortAudio API Header File
 * Latest version available at: http://www.audiomulch.com/portaudio/
 *
 * Copyright (c) 1999-2000 Ross Bencina and Phil Burk
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files
 * (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge,
 * publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * Any person wishing to distribute modifications to the Software is
 * requested to send the modifications to the original developer so that
 * they can be incorporated into the canonical version.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR
 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
 * CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 */

typedef int PaError;
typedef enum {
	paNoError = 0,

	paHostError = -10000,
	paInvalidChannelCount,
	paInvalidSampleRate,
	paInvalidDeviceId,
	paInvalidFlag,
	paSampleFormatNotSupported,
	paBadIODeviceCombination,
	paInsufficientMemory,
	paBufferTooBig,
	paBufferTooSmall,
	paNullCallback,
	paBadStreamPtr,
	paTimedOut,
	paInternalError
} PaErrorNum;

/*
	Pa_Initialize() is the library initialisation function - call this before
	using the library.
*/

PaError Pa_Initialize( void );

/*
	Pa_Terminate() is the library termination function - call this after
	using the library.
*/

PaError Pa_Terminate( void );

/*
	Return host specific error.
	This can be called after receiving a paHostError.
*/
long Pa_GetHostError( void );

/*
	Translate the error number into a human readable message.
*/
const char *Pa_GetErrorText( PaError errnum );

/*
	Sample formats

	These are formats used to pass sound data between the callback and the
	stream. Each device has a "native" format which may be used when optimum
	efficiency or control over conversion is required.

	Formats marked "always available" are supported (emulated) by all devices.

	The floating point representation uses +1.0 and -1.0 as the respective
	maximum and minimum.
	
*/

typedef unsigned long PaSampleFormat;
#define paFloat32      ((PaSampleFormat) (1<<0))	/*always available*/
#define paInt16        ((PaSampleFormat) (1<<1))	/*always available*/
#define paInt32        ((PaSampleFormat) (1<<2))	/*always available*/
#define paInt24        ((PaSampleFormat) (1<<3))
#define paPackedInt24  ((PaSampleFormat) (1<<4))
#define paInt8         ((PaSampleFormat) (1<<5))
#define paUInt8        ((PaSampleFormat) (1<<6))    /* unsigned 8 bit, 128 is "ground" */
#define paCustomFormat ((PaSampleFormat) (1<<16))

/*
	Device enumeration mechanism.

   	Device ids range from 0 to Pa_CountDevices()-1.

	Devices may support input, output or both. Device 0 is always the "default"
	device and should support at least stereo in and out if that is available
	on the taget platform _even_ if this involves kludging an input/output
	device on platforms that usually separate input from output. Other platform
	specific devices are specified by positive device ids.
*/

typedef int PaDeviceID;
#define paNoDevice -1

typedef struct{
	int structVersion; 
	const char *name;
	int maxInputChannels;
	int maxOutputChannels;
/* Number of discrete rates, or -1 if range supported. */
	int numSampleRates;
/* Array of supported sample rates, or {min,max} if range supported. */
	const double *sampleRates;
	PaSampleFormat nativeSampleFormats;
} PaDeviceInfo;


int Pa_CountDevices();
/*
	Pa_GetDefaultInputDeviceID(), Pa_GetDefaultOutputDeviceID()

	Return the default device ID or paNoDevice if there is no devices.
	The result can be passed to Pa_OpenStream().
	
	On the PC, the user can specify a default device by
	setting an environment variable. For example, to use device #1.

		set PA_RECOMMENDED_OUTPUT_DEVICE=1
	
	The user should first determine the available device ID by using
	the supplied application "pa_devs".
*/
PaDeviceID Pa_GetDefaultInputDeviceID( void );
PaDeviceID Pa_GetDefaultOutputDeviceID( void );

/*
	PaTimestamp is used to represent a continuous sample clock with arbitrary
	start time useful for syncronisation. The type is used in the outTime
	argument to the callback function and the result of Pa_StreamTime()
*/

typedef double PaTimestamp;

/*
	Pa_GetDeviceInfo() returns a pointer to an immutable PaDeviceInfo structure
	referring to the device specified by id.
	If id is out of range the function returns NULL.

	The returned structure is owned by the PortAudio implementation and must
	not be manipulated or freed. The pointer is guaranteed to be valid until
	between calls to Pa_Initialize() and Pa_Terminate().
*/

const PaDeviceInfo* Pa_GetDeviceInfo( PaDeviceID devID );

/*
	PortAudioCallback is implemented by clients of the portable audio api.

	inputBuffer and outputBuffer are arrays of interleaved samples,
	the format, packing and number of channels used by the buffers are
	determined by parameters to Pa_OpenStream() (see below).

	framesPerBuffer is the number of sample frames to be processed by the callback.

	outTime is the time in samples when the buffer(s) processed by
	this callback will begin being played at the audio output.
	See also Pa_StreamTime()

	userData is the value of a user supplied pointer passed to Pa_OpenStream()
	intended for storing synthesis data etc.

	return value:
	The callback can return a nonzero value to stop the stream. This may be
	useful in applications such as soundfile players where a specific duration
	of output is required. However, it is not necessary to utilise this mechanism
	as StopStream() will also terminate the stream. A callback returning a
	nonzero value must fill the entire outputBuffer.

	NOTE: None of the other stream functions may be called from within the
	callback function except for Pa_GetCPULoad().

*/

typedef int (PortAudioCallback)(
		void *inputBuffer, void *outputBuffer,
		unsigned long framesPerBuffer,
		PaTimestamp outTime, void *userData );


/*
	Stream flags

	These flags may be supplied (ored together) in the streamFlags argument to
	the Pa_OpenStream() function.

	[ suggestions? ]
*/

#define   paNoFlag      (0)
#define   paClipOff     (1<<0)   /* disable defult clipping of out of range samples */
#define   paDitherOff   (1<<1)   /* disable default dithering */
#define   paPlatformSpecificFlags (0x00010000)
typedef   unsigned long PaStreamFlags;

/*
	A single PortAudioStream provides multiple channels of real-time
	input and output audio streaming to a client application.
	Pointers to PortAudioStream objects are passed between PortAudio functions.
*/

typedef void PortAudioStream;
#define PaStream PortAudioStream

/*
	Pa_OpenStream() opens a stream for either input, output or both.

	stream is the address of a PortAudioStream pointer which will receive
	a pointer to the newly opened stream.

	inputDevice is the id of the device used for input (see PaDeviceID above.)
	inputDevice may be paNoDevice to indicate that an input device is not required.

	numInputChannels is the number of channels of sound to be delivered to the
	callback. It can range from 1 to the value of maxInputChannels in the
	device input record for the device specified in the inputDevice parameter.
	If inputDevice is paNoDevice numInputChannels is ignored.

	inputSampleFormat is the format of inputBuffer provided to the callback
	function. inputSampleFormat may be any of the formats described by the
	PaSampleFormat enumeration (see above). PortAudio guarantees support for
	the sound devices native formats (nativeSampleFormats in the device info
	record) and additionally 16 and 32 bit integer and 32 bit floating point
	formats. Support for other formats is implementation defined.

	inputDriverInfo is a pointer to an optional driver specific data structure
	containing additional information for device setup or stream processing.
	inputDriverInfo is never required for correct operation. If not used
	inputDriverInfo should be NULL.

	outputDevice is the id of the device used for output (see PaDeviceID above.)
	outputDevice may be paNoDevice to indicate that an output device is not required.

	numOutputChannels is the number of channels of sound to be supplied by the
	callback. See the definition of numInputChannels above for more details.

	outputSampleFormat is the sample format of the outputBuffer filled by the
	callback function. See the definition of inputSampleFormat above for more
	details.

	outputDriverInfo is a pointer to an optional driver specific data structure
	containing additional information for device setup or stream processing.
	outputDriverInfo is never required for correct operation. If not used
	outputDriverInfo should be NULL.

	sampleRate is the desired sampleRate for input and output

	framesPerBuffer is the length in sample frames of all internal sample buffers
	used for communication with platform specific audio routines. Wherever
	possible this corresponds to the framesPerBuffer parameter passed to the
	callback function.

	numberOfBuffers is the number of buffers used for multibuffered
	communication with the platform specific audio routines. This parameter is
	provided only as a guide - and does not imply that an implementation must
	use multibuffered i/o when reliable double buffering is available (such as
	SndPlayDoubleBuffer() on the Macintosh.)

	streamFlags may contain a combination of flags ORed together.
	These flags modify the behavior of the
	streaming process. Some flags may only be relevant to certain buffer formats.

	callback is a pointer to a client supplied function that is responsible
	for processing and filling input and output buffers (see above for details.)

	userData is a client supplied pointer which is passed to the callback
	function. It could for example, contain a pointer to instance data necessary
	for processing the audio buffers.

	return value:
	Apon success Pa_OpenStream() returns PaNoError and places a pointer to a
	valid PortAudioStream in the stream argument. The stream is inactive (stopped).
	If a call to Pa_OpenStream() fails a nonzero error code is returned (see
	PAError above) and the value of stream is invalid.

*/

PaError Pa_OpenStream( PortAudioStream** stream,
				PaDeviceID inputDevice,
				int numInputChannels,
				PaSampleFormat inputSampleFormat,
				void *inputDriverInfo,
				PaDeviceID outputDevice,
				int numOutputChannels,
				PaSampleFormat outputSampleFormat,
				void *outputDriverInfo,
				double sampleRate,
				unsigned long framesPerBuffer,
				unsigned long numberOfBuffers,
				PaStreamFlags streamFlags,
				PortAudioCallback *callback,
				void *userData );


/*
	Pa_OpenDefaultStream() is a simplified version of Pa_OpenStream() that
	opens the default input and/or ouput devices. Most parameters have
	identical meaning to their Pa_OpenStream() counterparts, with the following
	exceptions:

	If either numInputChannels or numOutputChannels is 0 the respective device
	is not opened (same as passing paNoDevice in the device arguments to Pa_OpenStream() )

	sampleFormat applies to both the input and output buffers.
*/

PaError Pa_OpenDefaultStream( PortAudioStream** stream,
				int numInputChannels,
				int numOutputChannels,
				PaSampleFormat sampleFormat,
				double sampleRate,
				unsigned long framesPerBuffer,
				unsigned long numberOfBuffers,
				PortAudioCallback *callback,
				void *userData );
	   
/*
	Pa_CloseStream() closes an audio stream, flushing any pending buffers.
*/

PaError Pa_CloseStream( PortAudioStream* );

/*
 	Pa_StartStream() and Pa_StopStream() begin and terminate audio processing.
	Pa_StopStream() waits until all pending audio buffers have been played.
    Pa_AbortStream() stops playing immediately without waiting for pending
    buffers to complete.
*/

PaError Pa_StartStream( PortAudioStream *stream );

PaError Pa_StopStream( PortAudioStream *stream );

PaError Pa_AbortStream( PortAudioStream *stream );

/*
	Pa_StreamActive() returns one when the stream is playing audio,
	zero when not playing, or a negative error number if the
	stream is invalid.
	The stream is active between calls to Pa_StartStream() and Pa_StopStream(),
	but may also become inactive if the callback returns a non-zero value.
	In the latter case, the stream is considered inactive after the last
	buffer has finished playing.
*/

PaError Pa_StreamActive( PortAudioStream *stream );

/*
	Pa_StreamTime() returns the current output time for the stream in samples.
	This time may be used as a time reference (for example syncronising audio to
	MIDI).
*/

PaTimestamp Pa_StreamTime( PortAudioStream *stream );

/*
	The "CPU Load" is a fraction of total CPU time consumed by the
	stream's audio processing.
	A value of 0.5 would imply that PortAudio and the sound generating
	callback was consuming roughly 50% of the available CPU time.
	This function may be called from the callback function or the application.
*/
double Pa_GetCPULoad( PortAudioStream* stream );

/*
	Use Pa_GetMinNumBuffers() to determine minimum number of buffers required for
	the current host based on minimum latency. 
	On the PC, for the DirectSound implementation, latency can be optionally set
	by user by setting an environment variable.
	For example, to set latency to 200 msec, put:
	
	   set PA_MIN_LATENCY_MSEC=200
	
	in the AUTOEXEC.BAT file and reboot.
	If the environment variable is not set, then the latency will be determined
	based on the OS. Windows NT has higher latency than Win95.
*/

int Pa_GetMinNumBuffers( int framesPerBuffer, double sampleRate );

/*
	Sleep for at least 'msec' milliseconds.
	You may sleep longer than the requested time so don't rely
	on this for accurate musical timing.
*/
void Pa_Sleep( long msec );

/*
	Return size in bytes of a single sample in a given PaSampleFormat
	or paSampleFormatNotSupported. 
*/
PaError Pa_GetSampleSize( PaSampleFormat format );

#ifdef __cplusplus
}
#endif /* __cplusplus */
#endif /* PORT_AUDIO_H */