comparison src/libsamplerate-0.1.9/examples/audio_out.c @ 41:481f5f8c5634

Current libsamplerate source

+/*
+** Copyright (c) 1999-2016, Erik de Castro Lopo <[e-mail]>
+** All rights reserved.
+**
+** This code is released under 2-clause BSD license. Please see the
+** file at : https://github.com/erikd/libsamplerate/blob/master/COPYING
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <config.h>
+
+#include "audio_out.h"
+
+#if HAVE_ALSA_ASOUNDLIB_H
+	#define ALSA_PCM_NEW_HW_PARAMS_API
+	#define ALSA_PCM_NEW_SW_PARAMS_API
+	#include <alsa/asoundlib.h>
+	#include <sys/time.h>
+#endif
+
+#if (HAVE_SNDFILE)
+
+#include <float_cast.h>
+
+#include <sndfile.h>
+
+#define	BUFFER_LEN		(2048)
+
+#define MAKE_MAGIC(a,b,c,d,e,f,g,h)		\
+			((a) + ((b) << 1) + ((c) << 2) + ((d) << 3) + ((e) << 4) + ((f) << 5) + ((g) << 6) + ((h) << 7))
+
+typedef	struct AUDIO_OUT_s
+{	int magic ;
+} AUDIO_OUT ;
+
+
+/*------------------------------------------------------------------------------
+**	Linux (ALSA and OSS) functions for playing a sound.
+*/
+
+#if defined (__linux__)
+
+#if HAVE_ALSA_ASOUNDLIB_H
+
+#define	ALSA_MAGIC		MAKE_MAGIC ('L', 'n', 'x', '-', 'A', 'L', 'S', 'A')
+
+typedef struct
+{	int magic ;
+	snd_pcm_t * dev ;
+	int channels ;
+} ALSA_AUDIO_OUT ;
+
+static int alsa_write_float (snd_pcm_t *alsa_dev, float *data, int frames, int channels) ;
+
+static AUDIO_OUT *
+alsa_open (int channels, unsigned samplerate)
+{	ALSA_AUDIO_OUT *alsa_out ;
+	const char * device = "default" ;
+	snd_pcm_hw_params_t *hw_params ;
+	snd_pcm_uframes_t buffer_size ;
+	snd_pcm_uframes_t alsa_period_size, alsa_buffer_frames ;
+	snd_pcm_sw_params_t *sw_params ;
+
+	int err ;
+
+	alsa_period_size = 1024 ;
+	alsa_buffer_frames = 4 * alsa_period_size ;
+
+	if ((alsa_out = calloc (1, sizeof (ALSA_AUDIO_OUT))) == NULL)
+	{	perror ("alsa_open : malloc ") ;
+		exit (1) ;
+		} ;
+
+	alsa_out->magic	= ALSA_MAGIC ;
+	alsa_out->channels = channels ;
+
+	if ((err = snd_pcm_open (&alsa_out->dev, device, SND_PCM_STREAM_PLAYBACK, 0)) < 0)
+	{	fprintf (stderr, "cannot open audio device \"%s\" (%s)\n", device, snd_strerror (err)) ;
+		goto catch_error ;
+		} ;
+
+	snd_pcm_nonblock (alsa_out->dev, 0) ;
+
+	if ((err = snd_pcm_hw_params_malloc (&hw_params)) < 0)
+	{	fprintf (stderr, "cannot allocate hardware parameter structure (%s)\n", snd_strerror (err)) ;
+		goto catch_error ;
+		} ;
+
+	if ((err = snd_pcm_hw_params_any (alsa_out->dev, hw_params)) < 0)
+	{	fprintf (stderr, "cannot initialize hardware parameter structure (%s)\n", snd_strerror (err)) ;
+		goto catch_error ;
+		} ;
+
+	if ((err = snd_pcm_hw_params_set_access (alsa_out->dev, hw_params, SND_PCM_ACCESS_RW_INTERLEAVED)) < 0)
+	{	fprintf (stderr, "cannot set access type (%s)\n", snd_strerror (err)) ;
+		goto catch_error ;
+		} ;
+
+	if ((err = snd_pcm_hw_params_set_format (alsa_out->dev, hw_params, SND_PCM_FORMAT_FLOAT)) < 0)
+	{	fprintf (stderr, "cannot set sample format (%s)\n", snd_strerror (err)) ;
+		goto catch_error ;
+		} ;
+
+	if ((err = snd_pcm_hw_params_set_rate_near (alsa_out->dev, hw_params, &samplerate, 0)) < 0)
+	{	fprintf (stderr, "cannot set sample rate (%s)\n", snd_strerror (err)) ;
+		goto catch_error ;
+		} ;
+
+	if ((err = snd_pcm_hw_params_set_channels (alsa_out->dev, hw_params, channels)) < 0)
+	{	fprintf (stderr, "cannot set channel count (%s)\n", snd_strerror (err)) ;
+		goto catch_error ;
+		} ;
+
+	if ((err = snd_pcm_hw_params_set_buffer_size_near (alsa_out->dev, hw_params, &alsa_buffer_frames)) < 0)
+	{	fprintf (stderr, "cannot set buffer size (%s)\n", snd_strerror (err)) ;
+		goto catch_error ;
+		} ;
+
+	if ((err = snd_pcm_hw_params_set_period_size_near (alsa_out->dev, hw_params, &alsa_period_size, 0)) < 0)
+	{	fprintf (stderr, "cannot set period size (%s)\n", snd_strerror (err)) ;
+		goto catch_error ;
+		} ;
+
+	if ((err = snd_pcm_hw_params (alsa_out->dev, hw_params)) < 0)
+	{	fprintf (stderr, "cannot set parameters (%s)\n", snd_strerror (err)) ;
+		goto catch_error ;
+		} ;
+
+	/* extra check: if we have only one period, this code won't work */
+	snd_pcm_hw_params_get_period_size (hw_params, &alsa_period_size, 0) ;
+	snd_pcm_hw_params_get_buffer_size (hw_params, &buffer_size) ;
+	if (alsa_period_size == buffer_size)
+	{	fprintf (stderr, "Can't use period equal to buffer size (%lu == %lu)", alsa_period_size, buffer_size) ;
+		goto catch_error ;
+		} ;
+
+	snd_pcm_hw_params_free (hw_params) ;
+
+	if ((err = snd_pcm_sw_params_malloc (&sw_params)) != 0)
+	{	fprintf (stderr, "%s: snd_pcm_sw_params_malloc: %s", __func__, snd_strerror (err)) ;
+		goto catch_error ;
+		} ;
+
+	if ((err = snd_pcm_sw_params_current (alsa_out->dev, sw_params)) != 0)
+	{	fprintf (stderr, "%s: snd_pcm_sw_params_current: %s", __func__, snd_strerror (err)) ;
+		goto catch_error ;
+		} ;
+
+	/* note: set start threshold to delay start until the ring buffer is full */
+	snd_pcm_sw_params_current (alsa_out->dev, sw_params) ;
+
+	if ((err = snd_pcm_sw_params_set_start_threshold (alsa_out->dev, sw_params, buffer_size)) < 0)
+	{	fprintf (stderr, "cannot set start threshold (%s)\n", snd_strerror (err)) ;
+		goto catch_error ;
+		} ;
+
+	if ((err = snd_pcm_sw_params (alsa_out->dev, sw_params)) != 0)
+	{	fprintf (stderr, "%s: snd_pcm_sw_params: %s", __func__, snd_strerror (err)) ;
+		goto catch_error ;
+		} ;
+
+	snd_pcm_sw_params_free (sw_params) ;
+
+	snd_pcm_reset (alsa_out->dev) ;
+
+catch_error :
+
+	if (err < 0 && alsa_out->dev != NULL)
+	{	snd_pcm_close (alsa_out->dev) ;
+		return NULL ;
+		} ;
+
+	return (AUDIO_OUT *) alsa_out ;
+} /* alsa_open */
+
+static void
+alsa_play (get_audio_callback_t callback, AUDIO_OUT *audio_out, void *callback_data)
+{	static float buffer [BUFFER_LEN] ;
+	ALSA_AUDIO_OUT *alsa_out ;
+	int	read_frames ;
+
+	if ((alsa_out = (ALSA_AUDIO_OUT*) audio_out) == NULL)
+	{	printf ("alsa_close : AUDIO_OUT is NULL.\n") ;
+		return ;
+		} ;
+
+	if (alsa_out->magic != ALSA_MAGIC)
+	{	printf ("alsa_close : Bad magic number.\n") ;
+		return ;
+		} ;
+
+	while ((read_frames = callback (callback_data, buffer, BUFFER_LEN / alsa_out->channels)))
+		alsa_write_float (alsa_out->dev, buffer, read_frames, alsa_out->channels) ;
+
+	return ;
+} /* alsa_play */
+
+static int
+alsa_write_float (snd_pcm_t *alsa_dev, float *data, int frames, int channels)
+{	static	int epipe_count = 0 ;
+
+	int total = 0 ;
+	int retval ;
+
+	if (epipe_count > 0)
+		epipe_count -- ;
+
+	while (total < frames)
+	{	retval = snd_pcm_writei (alsa_dev, data + total * channels, frames - total) ;
+
+		if (retval >= 0)
+		{	total += retval ;
+			if (total == frames)
+				return total ;
+
+			continue ;
+			} ;
+
+		switch (retval)
+		{	case -EAGAIN :
+					puts ("alsa_write_float: EAGAIN") ;
+					continue ;
+					break ;
+
+			case -EPIPE :
+					if (epipe_count > 0)
+					{	printf ("alsa_write_float: EPIPE %d\n", epipe_count) ;
+						if (epipe_count > 140)
+							return retval ;
+						} ;
+					epipe_count += 100 ;
+
+#if 0
+					if (0)
+					{	snd_pcm_status_t *status ;
+
+						snd_pcm_status_alloca (&status) ;
+						if ((retval = snd_pcm_status (alsa_dev, status)) < 0)
+							fprintf (stderr, "alsa_out: xrun. can't determine length\n") ;
+						else if (snd_pcm_status_get_state (status) == SND_PCM_STATE_XRUN)
+						{	struct timeval now, diff, tstamp ;
+
+							gettimeofday (&now, 0) ;
+							snd_pcm_status_get_trigger_tstamp (status, &tstamp) ;
+							timersub (&now, &tstamp, &diff) ;
+
+							fprintf (stderr, "alsa_write_float xrun: of at least %.3f msecs. resetting stream\n",
+									diff.tv_sec * 1000 + diff.tv_usec / 1000.0) ;
+							}
+						else
+							fprintf (stderr, "alsa_write_float: xrun. can't determine length\n") ;
+						} ;
+#endif
+
+					snd_pcm_prepare (alsa_dev) ;
+					break ;
+
+			case -EBADFD :
+					fprintf (stderr, "alsa_write_float: Bad PCM state.n") ;
+					return 0 ;
+					break ;
+
+			case -ESTRPIPE :
+					fprintf (stderr, "alsa_write_float: Suspend event.n") ;
+					return 0 ;
+					break ;
+
+			case -EIO :
+					puts ("alsa_write_float: EIO") ;
+					return 0 ;
+
+			default :
+					fprintf (stderr, "alsa_write_float: retval = %d\n", retval) ;
+					return 0 ;
+					break ;
+			} ; /* switch */
+		} ; /* while */
+
+	return total ;
+} /* alsa_write_float */
+
+static void
+alsa_close (AUDIO_OUT *audio_out)
+{	ALSA_AUDIO_OUT *alsa_out ;
+
+	if ((alsa_out = (ALSA_AUDIO_OUT*) audio_out) == NULL)
+	{	printf ("alsa_close : AUDIO_OUT is NULL.\n") ;
+		return ;
+		} ;
+
+	if (alsa_out->magic != ALSA_MAGIC)
+	{	printf ("alsa_close : Bad magic number.\n") ;
+		return ;
+		} ;
+
+	memset (alsa_out, 0, sizeof (ALSA_AUDIO_OUT)) ;
+
+	free (alsa_out) ;
+
+	return ;
+} /* alsa_close */
+
+#endif /* HAVE_ALSA_ASOUNDLIB_H */
+
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <sys/soundcard.h>
+
+#define	OSS_MAGIC		MAKE_MAGIC ('L', 'i', 'n', 'u', 'x', 'O', 'S', 'S')
+
+typedef struct
+{	int magic ;
+	int fd ;
+	int channels ;
+} OSS_AUDIO_OUT ;
+
+static AUDIO_OUT *opensoundsys_open (int channels, int samplerate) ;
+static void opensoundsys_play (get_audio_callback_t callback, AUDIO_OUT *audio_out, void *callback_data) ;
+static void opensoundsys_close (AUDIO_OUT *audio_out) ;
+
+
+static AUDIO_OUT *
+opensoundsys_open (int channels, int samplerate)
+{	OSS_AUDIO_OUT	*opensoundsys_out ;
+	int stereo, fmt, error ;
+
+	if ((opensoundsys_out = calloc (1, sizeof (OSS_AUDIO_OUT))) == NULL)
+	{	perror ("opensoundsys_open : malloc ") ;
+		exit (1) ;
+		} ;
+
+	opensoundsys_out->magic	= OSS_MAGIC ;
+	opensoundsys_out->channels = channels ;
+
+	if ((opensoundsys_out->fd = open ("/dev/dsp", O_WRONLY, 0)) == -1)
+	{	perror ("opensoundsys_open : open ") ;
+		exit (1) ;
+		} ;
+
+	stereo = 0 ;
+	if (ioctl (opensoundsys_out->fd, SNDCTL_DSP_STEREO, &stereo) == -1)
+	{ 	/* Fatal error */
+		perror ("opensoundsys_open : stereo ") ;
+		exit (1) ;
+		} ;
+
+	if (ioctl (opensoundsys_out->fd, SNDCTL_DSP_RESET, 0))
+	{	perror ("opensoundsys_open : reset ") ;
+		exit (1) ;
+		} ;
+
+	fmt = CPU_IS_BIG_ENDIAN ? AFMT_S16_BE : AFMT_S16_LE ;
+	if (ioctl (opensoundsys_out->fd, SNDCTL_DSP_SETFMT, &fmt) != 0)
+	{	perror ("opensoundsys_open_dsp_device : set format ") ;
+	    exit (1) ;
+  		} ;
+
+	if ((error = ioctl (opensoundsys_out->fd, SNDCTL_DSP_CHANNELS, &channels)) != 0)
+	{	perror ("opensoundsys_open : channels ") ;
+		exit (1) ;
+		} ;
+
+	if ((error = ioctl (opensoundsys_out->fd, SNDCTL_DSP_SPEED, &samplerate)) != 0)
+	{	perror ("opensoundsys_open : sample rate ") ;
+		exit (1) ;
+		} ;
+
+	if ((error = ioctl (opensoundsys_out->fd, SNDCTL_DSP_SYNC, 0)) != 0)
+	{	perror ("opensoundsys_open : sync ") ;
+		exit (1) ;
+		} ;
+
+	return 	(AUDIO_OUT*) opensoundsys_out ;
+} /* opensoundsys_open */
+
+static void
+opensoundsys_play (get_audio_callback_t callback, AUDIO_OUT *audio_out, void *callback_data)
+{	OSS_AUDIO_OUT *opensoundsys_out ;
+	static float float_buffer [BUFFER_LEN] ;
+	static short buffer [BUFFER_LEN] ;
+	int		k, read_frames ;
+
+	if ((opensoundsys_out = (OSS_AUDIO_OUT*) audio_out) == NULL)
+	{	printf ("opensoundsys_play : AUDIO_OUT is NULL.\n") ;
+		return ;
+		} ;
+
+	if (opensoundsys_out->magic != OSS_MAGIC)
+	{	printf ("opensoundsys_play : Bad magic number.\n") ;
+		return ;
+		} ;
+
+	while ((read_frames = callback (callback_data, float_buffer, BUFFER_LEN / opensoundsys_out->channels)))
+	{	for (k = 0 ; k < read_frames * opensoundsys_out->channels ; k++)
+			buffer [k] = lrint (32767.0 * float_buffer [k]) ;
+		(void) write (opensoundsys_out->fd, buffer, read_frames * opensoundsys_out->channels * sizeof (short)) ;
+		} ;
+
+	return ;
+} /* opensoundsys_play */
+
+static void
+opensoundsys_close (AUDIO_OUT *audio_out)
+{	OSS_AUDIO_OUT *opensoundsys_out ;
+
+	if ((opensoundsys_out = (OSS_AUDIO_OUT*) audio_out) == NULL)
+	{	printf ("opensoundsys_close : AUDIO_OUT is NULL.\n") ;
+		return ;
+		} ;
+
+	if (opensoundsys_out->magic != OSS_MAGIC)
+	{	printf ("opensoundsys_close : Bad magic number.\n") ;
+		return ;
+		} ;
+
+	memset (opensoundsys_out, 0, sizeof (OSS_AUDIO_OUT)) ;
+
+	free (opensoundsys_out) ;
+
+	return ;
+} /* opensoundsys_close */
+
+#endif /* __linux__ */
+
+/*------------------------------------------------------------------------------
+**	Mac OS X functions for playing a sound.
+*/
+
+#if (defined (__MACH__) && defined (__APPLE__)) /* MacOSX */
+
+#include <Carbon.h>
+#include <CoreAudio/AudioHardware.h>
+
+#define	MACOSX_MAGIC	MAKE_MAGIC ('M', 'a', 'c', ' ', 'O', 'S', ' ', 'X')
+
+typedef struct
+{	int magic ;
+	AudioStreamBasicDescription	format ;
+
+	UInt32 			buf_size ;
+	AudioDeviceID 	device ;
+
+	int		channels ;
+	int 	samplerate ;
+	int		buffer_size ;
+	int		done_playing ;
+
+	get_audio_callback_t	callback ;
+
+	void 	*callback_data ;
+} MACOSX_AUDIO_OUT ;
+
+static AUDIO_OUT *macosx_open (int channels, int samplerate) ;
+static void macosx_play (get_audio_callback_t callback, AUDIO_OUT *audio_out, void *callback_data) ;
+static void macosx_close (AUDIO_OUT *audio_out) ;
+
+static OSStatus
+macosx_audio_out_callback (AudioDeviceID device, const AudioTimeStamp* current_time,
+	const AudioBufferList* data_in, const AudioTimeStamp* time_in,
+	AudioBufferList* data_out, const AudioTimeStamp* time_out, void* client_data) ;
+
+
+static AUDIO_OUT *
+macosx_open (int channels, int samplerate)
+{	MACOSX_AUDIO_OUT *macosx_out ;
+	OSStatus	err ;
+	size_t 		count ;
+
+	if ((macosx_out = calloc (1, sizeof (MACOSX_AUDIO_OUT))) == NULL)
+	{	perror ("macosx_open : malloc ") ;
+		exit (1) ;
+		} ;
+
+	macosx_out->magic = MACOSX_MAGIC ;
+	macosx_out->channels = channels ;
+	macosx_out->samplerate = samplerate ;
+
+	macosx_out->device = kAudioDeviceUnknown ;
+
+	/*  get the default output device for the HAL */
+	count = sizeof (AudioDeviceID) ;
+	if ((err = AudioHardwareGetProperty (kAudioHardwarePropertyDefaultOutputDevice,
+				&count, (void *) &(macosx_out->device))) != noErr)
+	{	printf ("AudioHardwareGetProperty failed.\n") ;
+		free (macosx_out) ;
+		return NULL ;
+		} ;
+
+	/*  get the buffersize that the default device uses for IO */
+	count = sizeof (UInt32) ;
+	if ((err = AudioDeviceGetProperty (macosx_out->device, 0, false, kAudioDevicePropertyBufferSize,
+				&count, &(macosx_out->buffer_size))) != noErr)
+	{	printf ("AudioDeviceGetProperty (AudioDeviceGetProperty) failed.\n") ;
+		free (macosx_out) ;
+		return NULL ;
+		} ;
+
+	/*  get a description of the data format used by the default device */
+	count = sizeof (AudioStreamBasicDescription) ;
+	if ((err = AudioDeviceGetProperty (macosx_out->device, 0, false, kAudioDevicePropertyStreamFormat,
+				&count, &(macosx_out->format))) != noErr)
+	{	printf ("AudioDeviceGetProperty (kAudioDevicePropertyStreamFormat) failed.\n") ;
+		free (macosx_out) ;
+		return NULL ;
+		} ;
+
+	macosx_out->format.mSampleRate = samplerate ;
+	macosx_out->format.mChannelsPerFrame = channels ;
+
+	if ((err = AudioDeviceSetProperty (macosx_out->device, NULL, 0, false, kAudioDevicePropertyStreamFormat,
+				sizeof (AudioStreamBasicDescription), &(macosx_out->format))) != noErr)
+	{	printf ("AudioDeviceSetProperty (kAudioDevicePropertyStreamFormat) failed.\n") ;
+		free (macosx_out) ;
+		return NULL ;
+		} ;
+
+	/*  we want linear pcm */
+	if (macosx_out->format.mFormatID != kAudioFormatLinearPCM)
+	{	free (macosx_out) ;
+		return NULL ;
+		} ;
+
+	macosx_out->done_playing = 0 ;
+
+	/* Fire off the device. */
+	if ((err = AudioDeviceAddIOProc (macosx_out->device, macosx_audio_out_callback,
+			(void *) macosx_out)) != noErr)
+	{	printf ("AudioDeviceAddIOProc failed.\n") ;
+		free (macosx_out) ;
+		return NULL ;
+		} ;
+
+	return (MACOSX_AUDIO_OUT *) macosx_out ;
+} /* macosx_open */
+
+static void
+macosx_play (get_audio_callback_t callback, AUDIO_OUT *audio_out, void *callback_data)
+{	MACOSX_AUDIO_OUT	*macosx_out ;
+	OSStatus	err ;
+
+	if ((macosx_out = (MACOSX_AUDIO_OUT*) audio_out) == NULL)
+	{	printf ("macosx_play : AUDIO_OUT is NULL.\n") ;
+		return ;
+		} ;
+
+	if (macosx_out->magic != MACOSX_MAGIC)
+	{	printf ("macosx_play : Bad magic number.\n") ;
+		return ;
+		} ;
+
+	/* Set the callback function and callback data. */
+	macosx_out->callback = callback ;
+	macosx_out->callback_data = callback_data ;
+
+	err = AudioDeviceStart (macosx_out->device, macosx_audio_out_callback) ;
+	if (err != noErr)
+		printf ("AudioDeviceStart failed.\n") ;
+
+	while (macosx_out->done_playing == SF_FALSE)
+		usleep (10 * 1000) ; /* 10 000 milliseconds. */
+
+	return ;
+} /* macosx_play */
+
+static void
+macosx_close (AUDIO_OUT *audio_out)
+{	MACOSX_AUDIO_OUT	*macosx_out ;
+	OSStatus	err ;
+
+	if ((macosx_out = (MACOSX_AUDIO_OUT*) audio_out) == NULL)
+	{	printf ("macosx_close : AUDIO_OUT is NULL.\n") ;
+		return ;
+		} ;
+
+	if (macosx_out->magic != MACOSX_MAGIC)
+	{	printf ("macosx_close : Bad magic number.\n") ;
+		return ;
+		} ;
+
+
+	if ((err = AudioDeviceStop (macosx_out->device, macosx_audio_out_callback)) != noErr)
+	{	printf ("AudioDeviceStop failed.\n") ;
+		return ;
+		} ;
+
+	err = AudioDeviceRemoveIOProc (macosx_out->device, macosx_audio_out_callback) ;
+	if (err != noErr)
+	{	printf ("AudioDeviceRemoveIOProc failed.\n") ;
+		return ;
+		} ;
+
+} /* macosx_close */
+
+static OSStatus
+macosx_audio_out_callback (AudioDeviceID device, const AudioTimeStamp* current_time,
+	const AudioBufferList* data_in, const AudioTimeStamp* time_in,
+	AudioBufferList* data_out, const AudioTimeStamp* time_out, void* client_data)
+{	MACOSX_AUDIO_OUT	*macosx_out ;
+	int		k, size, frame_count, read_count ;
+	float	*buffer ;
+
+	if ((macosx_out = (MACOSX_AUDIO_OUT*) client_data) == NULL)
+	{	printf ("macosx_play : AUDIO_OUT is NULL.\n") ;
+		return 42 ;
+		} ;
+
+	if (macosx_out->magic != MACOSX_MAGIC)
+	{	printf ("macosx_play : Bad magic number.\n") ;
+		return 42 ;
+		} ;
+
+	size = data_out->mBuffers [0].mDataByteSize ;
+	frame_count = size / sizeof (float) / macosx_out->channels ;
+
+	buffer = (float*) data_out->mBuffers [0].mData ;
+
+	read_count = macosx_out->callback (macosx_out->callback_data, buffer, frame_count) ;
+
+	if (read_count < frame_count)
+	{	memset (&(buffer [read_count]), 0, (frame_count - read_count) * sizeof (float)) ;
+		macosx_out->done_playing = 1 ;
+		} ;
+
+	return noErr ;
+} /* macosx_audio_out_callback */
+
+#endif /* MacOSX */
+
+
+/*------------------------------------------------------------------------------
+**	Win32 functions for playing a sound.
+**
+**	This API sucks. Its needlessly complicated and is *WAY* too loose with
+**	passing pointers arounf in integers and and using char* pointers to
+**  point to data instead of short*. It plain sucks!
+*/
+
+#if (defined (_WIN32) || defined (WIN32))
+
+#include <windows.h>
+#include <mmsystem.h>
+
+#define	WIN32_BUFFER_LEN	(1<<15)
+#define	WIN32_MAGIC			MAKE_MAGIC ('W', 'i', 'n', '3', '2', 's', 'u', 'x')
+
+typedef struct
+{	int 			magic ;
+
+	HWAVEOUT		hwave ;
+	WAVEHDR			whdr [2] ;
+
+	HANDLE			Event ;
+
+	short			short_buffer [WIN32_BUFFER_LEN / sizeof (short)] ;
+	float			float_buffer [WIN32_BUFFER_LEN / sizeof (short) / 2] ;
+
+	int				bufferlen, current ;
+
+	int				channels ;
+
+	get_audio_callback_t	callback ;
+
+	void 			*callback_data ;
+} WIN32_AUDIO_OUT ;
+
+static AUDIO_OUT *win32_open (int channels, int samplerate) ;
+static void win32_play (get_audio_callback_t callback, AUDIO_OUT *audio_out, void *callback_data) ;
+static void win32_close (AUDIO_OUT *audio_out) ;
+
+static DWORD CALLBACK
+	win32_audio_out_callback (HWAVEOUT hwave, UINT msg, DWORD data, DWORD param1, DWORD param2) ;
+
+static AUDIO_OUT*
+win32_open (int channels, int samplerate)
+{	WIN32_AUDIO_OUT *win32_out ;
+
+	WAVEFORMATEX wf ;
+	int error ;
+
+	if ((win32_out = calloc (1, sizeof (WIN32_AUDIO_OUT))) == NULL)
+	{	perror ("win32_open : malloc ") ;
+		exit (1) ;
+		} ;
+
+	win32_out->magic	= WIN32_MAGIC ;
+	win32_out->channels = channels ;
+
+	win32_out->current = 0 ;
+
+	win32_out->Event = CreateEvent (0, FALSE, FALSE, 0) ;
+
+	wf.nChannels = channels ;
+	wf.nSamplesPerSec = samplerate ;
+	wf.nBlockAlign = channels * sizeof (short) ;
+
+	wf.wFormatTag = WAVE_FORMAT_PCM ;
+	wf.cbSize = 0 ;
+	wf.wBitsPerSample = 16 ;
+	wf.nAvgBytesPerSec = wf.nBlockAlign * wf.nSamplesPerSec ;
+
+	error = waveOutOpen (&(win32_out->hwave), WAVE_MAPPER, &wf, (DWORD) win32_audio_out_callback,
+							(DWORD) win32_out, CALLBACK_FUNCTION) ;
+	if (error)
+	{	puts ("waveOutOpen failed.") ;
+		free (win32_out) ;
+		return NULL ;
+		} ;
+
+	waveOutPause (win32_out->hwave) ;
+
+	return (WIN32_AUDIO_OUT *) win32_out ;
+} /* win32_open */
+
+static void
+win32_play (get_audio_callback_t callback, AUDIO_OUT *audio_out, void *callback_data)
+{	WIN32_AUDIO_OUT	*win32_out ;
+	int		error ;
+
+	if ((win32_out = (WIN32_AUDIO_OUT*) audio_out) == NULL)
+	{	printf ("win32_play : AUDIO_OUT is NULL.\n") ;
+		return ;
+		} ;
+
+	if (win32_out->magic != WIN32_MAGIC)
+	{	printf ("win32_play : Bad magic number (%d %d).\n", win32_out->magic, WIN32_MAGIC) ;
+		return ;
+		} ;
+
+	/* Set the callback function and callback data. */
+	win32_out->callback = callback ;
+	win32_out->callback_data = callback_data ;
+
+	win32_out->whdr [0].lpData = (char*) win32_out->short_buffer ;
+	win32_out->whdr [1].lpData = ((char*) win32_out->short_buffer) + sizeof (win32_out->short_buffer) / 2 ;
+
+	win32_out->whdr [0].dwBufferLength = sizeof (win32_out->short_buffer) / 2 ;
+	win32_out->whdr [1].dwBufferLength = sizeof (win32_out->short_buffer) / 2 ;
+
+	win32_out->bufferlen = sizeof (win32_out->short_buffer) / 2 / sizeof (short) ;
+
+	/* Prepare the WAVEHDRs */
+	if ((error = waveOutPrepareHeader (win32_out->hwave, &(win32_out->whdr [0]), sizeof (WAVEHDR))))
+	{	printf ("waveOutPrepareHeader [0] failed : %08X\n", error) ;
+		waveOutClose (win32_out->hwave) ;
+		return ;
+		} ;
+
+	if ((error = waveOutPrepareHeader (win32_out->hwave, &(win32_out->whdr [1]), sizeof (WAVEHDR))))
+	{	printf ("waveOutPrepareHeader [1] failed : %08X\n", error) ;
+		waveOutUnprepareHeader (win32_out->hwave, &(win32_out->whdr [0]), sizeof (WAVEHDR)) ;
+		waveOutClose (win32_out->hwave) ;
+		return ;
+		} ;
+
+	waveOutRestart (win32_out->hwave) ;
+
+	/* Fake 2 calls to the callback function to queue up enough audio. */
+	win32_audio_out_callback (0, MM_WOM_DONE, (DWORD) win32_out, 0, 0) ;
+	win32_audio_out_callback (0, MM_WOM_DONE, (DWORD) win32_out, 0, 0) ;
+
+	/* Wait for playback to finish. The callback notifies us when all
+	** wave data has been played.
+	*/
+	WaitForSingleObject (win32_out->Event, INFINITE) ;
+
+	waveOutPause (win32_out->hwave) ;
+	waveOutReset (win32_out->hwave) ;
+
+	waveOutUnprepareHeader (win32_out->hwave, &(win32_out->whdr [0]), sizeof (WAVEHDR)) ;
+	waveOutUnprepareHeader (win32_out->hwave, &(win32_out->whdr [1]), sizeof (WAVEHDR)) ;
+
+	waveOutClose (win32_out->hwave) ;
+	win32_out->hwave = 0 ;
+
+	return ;
+} /* win32_play */
+
+static void
+win32_close (AUDIO_OUT *audio_out)
+{	WIN32_AUDIO_OUT *win32_out ;
+
+	if ((win32_out = (WIN32_AUDIO_OUT*) audio_out) == NULL)
+	{	printf ("win32_close : AUDIO_OUT is NULL.\n") ;
+		return ;
+		} ;
+
+	if (win32_out->magic != WIN32_MAGIC)
+	{	printf ("win32_close : Bad magic number.\n") ;
+		return ;
+		} ;
+
+	memset (win32_out, 0, sizeof (WIN32_AUDIO_OUT)) ;
+
+	free (win32_out) ;
+} /* win32_close */
+
+static DWORD CALLBACK
+win32_audio_out_callback (HWAVEOUT hwave, UINT msg, DWORD data, DWORD param1, DWORD param2)
+{	WIN32_AUDIO_OUT	*win32_out ;
+	int		read_count, frame_count, k ;
+	short	*sptr ;
+
+	/*
+	** I consider this technique of passing a pointer via an integer as
+	** fundamentally broken but thats the way microsoft has defined the
+	** interface.
+	*/
+	if ((win32_out = (WIN32_AUDIO_OUT*) data) == NULL)
+	{	printf ("win32_audio_out_callback : AUDIO_OUT is NULL.\n") ;
+		return 1 ;
+		} ;
+
+	if (win32_out->magic != WIN32_MAGIC)
+	{	printf ("win32_audio_out_callback : Bad magic number (%d %d).\n", win32_out->magic, WIN32_MAGIC) ;
+		return 1 ;
+		} ;
+
+	if (msg != MM_WOM_DONE)
+		return 0 ;
+
+	/* Do the actual audio. */
+	sample_count = win32_out->bufferlen ;
+	frame_count = sample_count / win32_out->channels ;
+
+	read_count = win32_out->callback (win32_out->callback_data, win32_out->float_buffer, frame_count) ;
+
+	sptr = (short*) win32_out->whdr [win32_out->current].lpData ;
+
+	for (k = 0 ; k < read_count ; k++)
+		sptr [k] = lrint (32767.0 * win32_out->float_buffer [k]) ;
+
+	if (read_count > 0)
+	{	/* Fix buffer length is only a partial block. */
+		if (read_count * sizeof (short) < win32_out->bufferlen)
+			win32_out->whdr [win32_out->current].dwBufferLength = read_count * sizeof (short) ;
+
+		/* Queue the WAVEHDR */
+		waveOutWrite (win32_out->hwave, (LPWAVEHDR) &(win32_out->whdr [win32_out->current]), sizeof (WAVEHDR)) ;
+		}
+	else
+	{	/* Stop playback */
+		waveOutPause (win32_out->hwave) ;
+
+		SetEvent (win32_out->Event) ;
+		} ;
+
+	win32_out->current = (win32_out->current + 1) % 2 ;
+
+	return 0 ;
+} /* win32_audio_out_callback */
+
+#endif /* Win32 */
+
+/*------------------------------------------------------------------------------
+**	Solaris.
+*/
+
+#if (defined (sun) && defined (unix)) /* ie Solaris */
+
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <sys/audioio.h>
+
+#define	SOLARIS_MAGIC	MAKE_MAGIC ('S', 'o', 'l', 'a', 'r', 'i', 's', ' ')
+
+typedef struct
+{	int magic ;
+	int fd ;
+	int channels ;
+	int samplerate ;
+} SOLARIS_AUDIO_OUT ;
+
+static AUDIO_OUT *solaris_open (int channels, int samplerate) ;
+static void solaris_play (get_audio_callback_t callback, AUDIO_OUT *audio_out, void *callback_data) ;
+static void solaris_close (AUDIO_OUT *audio_out) ;
+
+static AUDIO_OUT *
+solaris_open (int channels, int samplerate)
+{	SOLARIS_AUDIO_OUT	*solaris_out ;
+	audio_info_t		audio_info ;
+	int					error ;
+
+	if ((solaris_out = calloc (1, sizeof (SOLARIS_AUDIO_OUT))) == NULL)
+	{	perror ("solaris_open : malloc ") ;
+		exit (1) ;
+		} ;
+
+	solaris_out->magic		= SOLARIS_MAGIC ;
+	solaris_out->channels	= channels ;
+	solaris_out->samplerate	= channels ;
+
+	/* open the audio device - write only, non-blocking */
+	if ((solaris_out->fd = open ("/dev/audio", O_WRONLY | O_NONBLOCK)) < 0)
+	{	perror ("open (/dev/audio) failed") ;
+		exit (1) ;
+		} ;
+
+	/*	Retrive standard values. */
+	AUDIO_INITINFO (&audio_info) ;
+
+	audio_info.play.sample_rate = samplerate ;
+	audio_info.play.channels = channels ;
+	audio_info.play.precision = 16 ;
+	audio_info.play.encoding = AUDIO_ENCODING_LINEAR ;
+	audio_info.play.gain = AUDIO_MAX_GAIN ;
+	audio_info.play.balance = AUDIO_MID_BALANCE ;
+
+	if ((error = ioctl (solaris_out->fd, AUDIO_SETINFO, &audio_info)))
+	{	perror ("ioctl (AUDIO_SETINFO) failed") ;
+		exit (1) ;
+		} ;
+
+	return 	(AUDIO_OUT*) solaris_out ;
+} /* solaris_open */
+
+static void
+solaris_play (get_audio_callback_t callback, AUDIO_OUT *audio_out, void *callback_data)
+{	SOLARIS_AUDIO_OUT *solaris_out ;
+	static float float_buffer [BUFFER_LEN] ;
+	static short buffer [BUFFER_LEN] ;
+	int		k, read_frames ;
+
+	if ((solaris_out = (SOLARIS_AUDIO_OUT*) audio_out) == NULL)
+	{	printf ("solaris_play : AUDIO_OUT is NULL.\n") ;
+		return ;
+		} ;
+
+	if (solaris_out->magic != SOLARIS_MAGIC)
+	{	printf ("solaris_play : Bad magic number.\n") ;
+		return ;
+		} ;
+
+	while ((read_frames = callback (callback_data, float_buffer, BUFFER_LEN / solaris_out->channels)))
+	{	for (k = 0 ; k < read_frames * solaris_out->channels ; k++)
+			buffer [k] = lrint (32767.0 * float_buffer [k]) ;
+		write (solaris_out->fd, buffer, read_frames * solaris_out->channels * sizeof (short)) ;
+		} ;
+
+	return ;
+} /* solaris_play */
+
+static void
+solaris_close (AUDIO_OUT *audio_out)
+{	SOLARIS_AUDIO_OUT *solaris_out ;
+
+	if ((solaris_out = (SOLARIS_AUDIO_OUT*) audio_out) == NULL)
+	{	printf ("solaris_close : AUDIO_OUT is NULL.\n") ;
+		return ;
+		} ;
+
+	if (solaris_out->magic != SOLARIS_MAGIC)
+	{	printf ("solaris_close : Bad magic number.\n") ;
+		return ;
+		} ;
+
+	memset (solaris_out, 0, sizeof (SOLARIS_AUDIO_OUT)) ;
+
+	free (solaris_out) ;
+
+	return ;
+} /* solaris_close */
+
+#endif /* Solaris */
+
+/*==============================================================================
+**	Main function.
+*/
+
+AUDIO_OUT *
+audio_open (int channels, int samplerate)
+{
+#if defined (__linux__)
+	#if HAVE_ALSA_ASOUNDLIB_H
+		if (access ("/proc/asound/cards", R_OK) == 0)
+			return alsa_open (channels, samplerate) ;
+	#endif
+		return opensoundsys_open (channels, samplerate) ;
+#elif (defined (__MACH__) && defined (__APPLE__))
+	return macosx_open (channels, samplerate) ;
+#elif (defined (sun) && defined (unix))
+	return solaris_open (channels, samplerate) ;
+#elif (defined (_WIN32) || defined (WIN32))
+	return win32_open (channels, samplerate) ;
+#else
+	#warning "*** Playing sound not yet supported on this platform."
+	#warning "*** Please feel free to submit a patch."
+	printf ("Error : Playing sound not yet supported on this platform.\n") ;
+	return NULL ;
+#endif
+
+
+	return NULL ;
+} /* audio_open */
+
+void
+audio_play (get_audio_callback_t callback, AUDIO_OUT *audio_out, void *callback_data)
+{
+
+	if (callback == NULL)
+	{	printf ("Error : bad callback pointer.\n") ;
+		return ;
+		} ;
+
+	if (audio_out == NULL)
+	{	printf ("Error : bad audio_out pointer.\n") ;
+		return ;
+		} ;
+
+	if (callback_data == NULL)
+	{	printf ("Error : bad callback_data pointer.\n") ;
+		return ;
+		} ;
+
+#if defined (__linux__)
+	#if HAVE_ALSA_ASOUNDLIB_H
+		if (audio_out->magic == ALSA_MAGIC)
+			alsa_play (callback, audio_out, callback_data) ;
+	#endif
+		opensoundsys_play (callback, audio_out, callback_data) ;
+#elif (defined (__MACH__) && defined (__APPLE__))
+	macosx_play (callback, audio_out, callback_data) ;
+#elif (defined (sun) && defined (unix))
+	solaris_play (callback, audio_out, callback_data) ;
+#elif (defined (_WIN32) || defined (WIN32))
+	win32_play (callback, audio_out, callback_data) ;
+#else
+	#warning "*** Playing sound not yet supported on this platform."
+	#warning "*** Please feel free to submit a patch."
+	printf ("Error : Playing sound not yet supported on this platform.\n") ;
+	return ;
+#endif
+
+	return ;
+} /* audio_play */
+
+void
+audio_close (AUDIO_OUT *audio_out)
+{
+#if defined (__linux__)
+	#if HAVE_ALSA_ASOUNDLIB_H
+		if (audio_out->magic == ALSA_MAGIC)
+			alsa_close (audio_out) ;
+	#endif
+	opensoundsys_close (audio_out) ;
+#elif (defined (__MACH__) && defined (__APPLE__))
+	macosx_close (audio_out) ;
+#elif (defined (sun) && defined (unix))
+	solaris_close (audio_out) ;
+#elif (defined (_WIN32) || defined (WIN32))
+	win32_close (audio_out) ;
+#else
+	#warning "*** Playing sound not yet supported on this platform."
+	#warning "*** Please feel free to submit a patch."
+	printf ("Error : Playing sound not yet supported on this platform.\n") ;
+	return ;
+#endif
+
+	return ;
+} /* audio_close */
+
+#else /* (HAVE_SNDFILE == 0) */
+
+/* Do not have libsndfile installed so just return. */
+
+AUDIO_OUT *
+audio_open (int channels, int samplerate)
+{
+	(void) channels ;
+	(void) samplerate ;
+
+	return NULL ;
+} /* audio_open */
+
+void
+audio_play (get_audio_callback_t callback, AUDIO_OUT *audio_out, void *callback_data)
+{
+	(void) callback ;
+	(void) audio_out ;
+	(void) callback_data ;
+
+	return ;
+} /* audio_play */
+
+void
+audio_close (AUDIO_OUT *audio_out)
+{
+	audio_out = audio_out ;
+
+	return ;
+} /* audio_close */
+
+#endif /* HAVE_SNDFILE */
+