/*

	audio: audio output interface

	copyright ?-2016 by the mpg123 project - free software under the terms of the LGPL 2.1

	see COPYING and AUTHORS files in distribution or http://mpg123.org

	initially written by Michael Hipp

*/

#include "out123_int.h"

#include "wav.h"

#ifndef NOXFERMEM

#include "buffer.h"

static int have_buffer(out123_handle *ao)

{

	return (ao->buffer_pid != -1);

}

#endif

#include "stringlists.h"

#include "debug.h"

/* An output that is live and does not deal with pausing itself.

   The device needs to be closed if we stop feeding. */

#define SENSITIVE_OUTPUT(ao) \

  (    (ao)->propflags & OUT123_PROP_LIVE \

  && !((ao)->propflags & OUT123_PROP_PERSISTENT) )

static const char *default_name = "out123";

static int modverbose(out123_handle *ao, int final)

{

	debug3("modverbose: %x %x %x"

	,	(unsigned)ao->flags, (unsigned)ao->auxflags, (unsigned)OUT123_QUIET);

	return AOQUIET

	?	(final ? 0 : -1)

	:	ao->verbose;

}

static void check_output_module( out123_handle *ao

,	const char *name, const char *device, int final );

static void out123_clear_module(out123_handle *ao)

{

	ao->open = NULL;

	ao->get_formats = NULL;

	ao->write = NULL;

	ao->flush = NULL;

	ao->drain = NULL;

	ao->close = NULL;

	ao->deinit = NULL;

	ao->module = NULL;

	ao->userptr = NULL;

	ao->fn = -1;

	/* The default is live output devices, files are the special case. */

	ao->propflags = OUT123_PROP_LIVE;

}

/* Ensure that real name is not leaked, needs to be freed before any call to

   ao->open(ao). One might free it on closing already, but it might be sensible

   to keep it around, might still be the same after re-opening. */

static int aoopen(out123_handle *ao)

{

	if(ao->realname)

	{

		free(ao->realname);

		ao->realname = NULL;

	}

	return ao->open(ao);

}

out123_handle* attribute_align_arg out123_new(void)

{

	out123_handle* ao = malloc( sizeof( out123_handle ) );

	if(!ao)

		return NULL;

	ao->errcode = 0;

#ifndef NOXFERMEM

	ao->buffer_pid = -1;

	ao->buffer_fd[0] = -1;

	ao->buffer_fd[1] = -1;

	ao->buffermem = NULL;

#endif

	out123_clear_module(ao);

	ao->name = compat_strdup(default_name);

	ao->realname = NULL;

	ao->driver = NULL;

	ao->device = NULL;

	ao->flags = OUT123_KEEP_PLAYING;

	ao->rate = -1;

	ao->gain = -1;

	ao->channels = -1;

	ao->format = -1;

	ao->framesize = 0;

	ao->state = play_dead;

	ao->auxflags = 0;

	ao->preload = 0.;

	ao->verbose = 0;

	ao->device_buffer = 0.;

	ao->bindir = NULL;

	return ao;

}

void attribute_align_arg out123_del(out123_handle *ao)

{

	debug2("[%ld]out123_del(%p)", (long)getpid(), (void*)ao);

	if(!ao) return;

	out123_close(ao); /* TODO: That talks to the buffer if present. */

	out123_set_buffer(ao, 0);

#ifndef NOXFERMEM

	if(have_buffer(ao)) buffer_exit(ao);

#endif

	if(ao->name)

		free(ao->name);

	if(ao->bindir)

		free(ao->bindir);

	free(ao);

}

/* Error reporting */

/* Carefully keep that in sync with the error enum! */

/* Sizing according to contents so that we can check! */

static const char *const errstring[] =

{

	"no problem"

,	"out of memory"

,	"bad driver name"

,	"failure loading driver module"

,	"no driver loaded"

,	"no active audio device"

,	"some device playback error"

,	"failed to open device"

,	"buffer (communication) error"

,	"basic module system error"

,	"bad function argument(s)"

,	"unknown parameter code"

,	"attempt to set read-only parameter"

,	"invalid out123 handle"

};

const char* attribute_align_arg out123_strerror(out123_handle *ao)

{

	return out123_plain_strerror(out123_errcode(ao));

}

int out123_errcode(out123_handle *ao)

{

	if(!ao) return OUT123_BAD_HANDLE;

	else    return ao->errcode;

}

const char* attribute_align_arg out123_plain_strerror(int errcode)

{

	if(errcode == OUT123_ERR)

		return "some generic error";

	if(errcode >= OUT123_ERRCOUNT || errcode < 0)

		return "invalid error code";

	/* Let's be paranoid, one _may_ forget to extend errstrings when

	   adding a new entry to the enum. */

	if(errcode >= sizeof(errstring)/sizeof(char*))

		return "outdated error list (library bug)";

	return errstring[errcode];

}

static int out123_seterr(out123_handle *ao, enum out123_error errcode)

{

	if(!ao)

		return OUT123_ERR;

	ao->errcode = errcode;

	return errcode == OUT123_OK ? OUT123_OK : OUT123_ERR;

}

/* pre-playback setup */

int attribute_align_arg

out123_set_buffer(out123_handle *ao, size_t buffer_bytes)

{

	debug2("out123_set_buffer(%p, %"SIZE_P")", (void*)ao, (size_p)buffer_bytes);

	if(!ao)

		return OUT123_ERR;

	ao->errcode = 0;

	/* Close any audio output module if present, also kill of buffer if present,

	   then start new buffer process with newly allocated storage if given

	   size is non-zero. */

	out123_close(ao);

#ifndef NOXFERMEM

	if(have_buffer(ao))

		buffer_exit(ao);

	if(buffer_bytes)

		return buffer_init(ao, buffer_bytes);

#endif

	return 0;

}

int attribute_align_arg

out123_param( out123_handle *ao, enum out123_parms code

            , long value, double fvalue, const char *svalue )

{

	int ret = 0;

	debug4("out123_param(%p, %i, %li, %g)", (void*)ao, (int)code, value, fvalue);

	if(!ao)

		return OUT123_ERR;

	ao->errcode = 0;

	switch(code)

	{

		case OUT123_FLAGS:

			ao->flags = (int)value;

		break;

		case OUT123_PRELOAD:

			ao->preload = fvalue;

		break;

		case OUT123_GAIN:

			ao->gain = value;

		break;

		case OUT123_VERBOSE:

			ao->verbose = (int)value;

		break;

		case OUT123_DEVICEBUFFER:

			ao->device_buffer = fvalue;

		break;

		case OUT123_PROPFLAGS:

			ao->errcode = OUT123_SET_RO_PARAM;

			ret = OUT123_ERR;

		break;

		case OUT123_NAME:

			if(ao->name)

				free(ao->name);

			ao->name = compat_strdup(svalue ? svalue : default_name);

		break;

		case OUT123_BINDIR:

			if(ao->bindir)

				free(ao->bindir);

			ao->bindir = compat_strdup(svalue);

		break;

		default:

			ao->errcode = OUT123_BAD_PARAM;

			if(!AOQUIET) error1("bad parameter code %i", (int)code);

			ret = OUT123_ERR;

	}

#ifndef NOXFERMEM

	/* If there is a buffer, it needs to update its copy of parameters. */

	if(have_buffer(ao))

		/* No error check; if that fails, buffer is dead and we will notice

		   soon enough. */

		buffer_sync_param(ao);

#endif

	return ret;

}

int attribute_align_arg

out123_getparam( out123_handle *ao, enum out123_parms code

               , long *ret_value, double *ret_fvalue, char* *ret_svalue )

{

	int ret = 0;

	long value = 0;

	double fvalue = 0.;

	char *svalue = NULL;

	debug4( "out123_getparam(%p, %i, %p, %p)"

	,	(void*)ao, (int)code, (void*)ret_value, (void*)ret_fvalue );

	if(!ao)

		return OUT123_ERR;

	ao->errcode = 0;

	switch(code)

	{

		case OUT123_FLAGS:

			value = ao->flags;

		break;

		case OUT123_PRELOAD:

			fvalue = ao->preload;

		break;

		case OUT123_GAIN:

			value = ao->gain;

		break;

		case OUT123_VERBOSE:

			value = ao->verbose;

		break;

		case OUT123_DEVICEBUFFER:

			fvalue = ao->device_buffer;

		break;

		case OUT123_PROPFLAGS:

			value = ao->propflags;

		break;

		case OUT123_NAME:

			svalue = ao->realname ? ao->realname : ao->name;

		break;

		case OUT123_BINDIR:

			svalue = ao->bindir;

		break;

		default:

			if(!AOQUIET) error1("bad parameter code %i", (int)code);

			ao->errcode = OUT123_BAD_PARAM;

			ret = OUT123_ERR;

	}

	if(!ret)

	{

		if(ret_value)  *ret_value  = value;

		if(ret_fvalue) *ret_fvalue = fvalue;

		if(ret_svalue) *ret_svalue = svalue;

	}

	return ret;

}

int attribute_align_arg

out123_param_from(out123_handle *ao, out123_handle* from_ao)

{

	debug2("out123_param_from(%p, %p)", (void*)ao, (void*)from_ao);

	if(!ao || !from_ao) return -1;

	ao->flags     = from_ao->flags;

	ao->preload   = from_ao->preload;

	ao->gain      = from_ao->gain;

	ao->device_buffer = from_ao->device_buffer;

	ao->verbose   = from_ao->verbose;

	if(ao->name)

		free(ao->name);

	ao->name = compat_strdup(from_ao->name);

	if(ao->bindir)

		free(ao->bindir);

	ao->bindir = compat_strdup(from_ao->bindir);

	return 0;

}

#ifndef NOXFERMEM

/* Serialization of tunable parameters to communicate them between

   main process and buffer. Make sure these two stay in sync ... */

int write_parameters(out123_handle *ao, int who)

{

	int fd = ao->buffermem->fd[who];

	if(

		GOOD_WRITEVAL(fd, ao->flags)

	&&	GOOD_WRITEVAL(fd, ao->preload)

	&&	GOOD_WRITEVAL(fd, ao->gain)

	&&	GOOD_WRITEVAL(fd, ao->device_buffer)

	&&	GOOD_WRITEVAL(fd, ao->verbose)

	&&	GOOD_WRITEVAL(fd, ao->propflags)

	&& !xfer_write_string(ao, who, ao->name)

	&& !xfer_write_string(ao, who, ao->bindir)

	)

		return 0;

	else

		return -1;

}

int read_parameters(out123_handle *ao

,	int who, byte *prebuf, int *preoff, int presize)

{

	int fd = ao->buffermem->fd[who];

#define GOOD_READVAL_BUF(fd, val) \

	!read_buf(fd, &val, sizeof(val), prebuf, preoff, presize)

	if(

		GOOD_READVAL_BUF(fd, ao->flags)

	&&	GOOD_READVAL_BUF(fd, ao->preload)

	&&	GOOD_READVAL_BUF(fd, ao->gain)

	&&	GOOD_READVAL_BUF(fd, ao->device_buffer)

	&&	GOOD_READVAL_BUF(fd, ao->verbose)

	&&	GOOD_READVAL_BUF(fd, ao->propflags)

	&& !xfer_read_string(ao, who, &ao->name)

	&& !xfer_read_string(ao, who, &ao->bindir)

	)

		return 0;

	else

		return -1;

#undef GOOD_READVAL_BUF

}

#endif

int attribute_align_arg

out123_open(out123_handle *ao, const char* driver, const char* device)

{

	debug4( "[%ld]out123_open(%p, %s, %s)", (long)getpid(), (void*)ao

	,	driver ? driver : "<nil>", device ? device : "<nil>" );

	if(!ao)

		return OUT123_ERR;

	ao->errcode = 0;

	out123_close(ao);

	debug("out123_open() continuing");

	/* Ensure that audio format is freshly set for "no format yet" mode.

	   In out123_start*/

	ao->rate = -1;

	ao->channels = -1;

	ao->format = -1;

#ifndef NOXFERMEM

	if(have_buffer(ao))

	{

		if(buffer_open(ao, driver, device))

			return OUT123_ERR;

	}

	else

#endif

	{

		/* We just quickly check if the device can be accessed at all,

		   same as out123_encodings! */

		char *nextname, *modnames;

		const char *names = driver ? driver : DEFAULT_OUTPUT_MODULE;

		if(!names) return out123_seterr(ao, OUT123_BAD_DRIVER_NAME);

		/* It is ridiculous how these error messages are larger than the pieces

		   of memory they are about! */

		if(device && !(ao->device = compat_strdup(device)))

		{

			if(!AOQUIET) error("OOM device name copy");

			return out123_seterr(ao, OUT123_DOOM);

		}

		if(!(modnames = compat_strdup(names)))

		{

			out123_close(ao); /* Frees ao->device, too. */

			if(!AOQUIET) error("OOM driver names");

			return out123_seterr(ao, OUT123_DOOM);

		}

		/* Now loop over the list of possible modules to find one that works. */

		nextname = strtok(modnames, ",");

		while(!ao->open && nextname)

		{

			char *curname = nextname;

			nextname = strtok(NULL, ",");

			check_output_module(ao, curname, device, !nextname);

			if(ao->open)

			{

				if(AOVERBOSE(2))

					fprintf(stderr, "Chosen output module: %s\n", curname);

				/* A bit redundant, but useful when it's a fake module. */

				if(!(ao->driver = compat_strdup(curname)))

				{

					out123_close(ao);

					if(!AOQUIET) error("OOM driver name");

					return out123_seterr(ao, OUT123_DOOM);

				}

			}

		}

		free(modnames);

		if(!ao->open) /* At least an open() routine must be present. */

		{

			if(!AOQUIET)

				error2("Found no driver out of [%s] working with device %s."

				,	names, device ? device : "<default>");

			/* Proper more detailed error code could be set already. */

			if(ao->errcode == OUT123_OK)

				ao->errcode = OUT123_BAD_DRIVER;

			return OUT123_ERR;

		}

	}

	/* Got something. */

	ao->state = play_stopped;

	return OUT123_OK;

}

/* Be resilient, always do cleanup work regardless of state. */

void attribute_align_arg out123_close(out123_handle *ao)

{

	debug2("[%ld]out123_close(%p)", (long)getpid(), (void*)ao);

	if(!ao)

		return;

	ao->errcode = 0;

	out123_drain(ao);

	out123_stop(ao);

#ifndef NOXFERMEM

	if(have_buffer(ao))

		buffer_close(ao);

	else

#endif

	{

		if(ao->deinit)

			ao->deinit(ao);

		if(ao->module)

			close_module(ao->module, modverbose(ao, 0));

		/* Null module methods and pointer. */

		out123_clear_module(ao);

	}

	/* These copies exist in addition to the ones for the buffer. */

	if(ao->driver)

		free(ao->driver);

	ao->driver = NULL;

	if(ao->device)	

		free(ao->device);

	ao->device = NULL;

	if(ao->realname)

		free(ao->realname);

	ao->realname = NULL;

	ao->state = play_dead;

}

int attribute_align_arg 

out123_start(out123_handle *ao, long rate, int channels, int encoding)

{

	debug5( "[%ld]out123_start(%p, %li, %i, %i)", (long)getpid()

	,	(void*)ao, rate, channels, encoding );

	if(!ao)

		return OUT123_ERR;

	ao->errcode = 0;

	out123_stop(ao);

	debug("out123_start() continuing");

	if(ao->state != play_stopped)

		return out123_seterr(ao, OUT123_NO_DRIVER);

	/* Stored right away as parameters for ao->open() and also for reference.

	   framesize needed for out123_play(). */

	ao->rate      = rate;

	ao->channels  = channels;

	ao->format    = encoding;

	ao->framesize = out123_encsize(encoding)*channels;

#ifndef NOXFERMEM

	if(have_buffer(ao))

	{

		if(!buffer_start(ao))

		{

			ao->state = play_live;

			return OUT123_OK;

		}

		else

			return OUT123_ERR;

	}

	else

#endif

	{

		if(aoopen(ao) < 0)

			return out123_seterr(ao, OUT123_DEV_OPEN);

		ao->state = play_live;

		return OUT123_OK;

	}

}

void attribute_align_arg out123_pause(out123_handle *ao)

{

	debug3( "[%ld]out123_pause(%p) %i", (long)getpid()

	,	(void*)ao, ao ? (int)ao->state : -1 );

	if(ao && ao->state == play_live)

	{

#ifndef NOXFERMEM

		if(have_buffer(ao)){ debug("pause with buffer"); buffer_pause(ao); }

		else

#endif

		{

debug1("pause without buffer, sensitive=%d", SENSITIVE_OUTPUT(ao));

			/* Close live devices to avoid underruns. */

			if( SENSITIVE_OUTPUT(ao)

			  && ao->close && ao->close(ao) && !AOQUIET )

				error("trouble closing device");

		}

		ao->state = play_paused;

	}

}

void attribute_align_arg out123_continue(out123_handle *ao)

{

	debug3( "[%ld]out123_continue(%p) %i", (long)getpid()

	,	(void*)ao, ao ? (int)ao->state : -1 );

	if(ao && ao->state == play_paused)

	{

#ifndef NOXFERMEM

		if(have_buffer(ao)) buffer_continue(ao);

		else

#endif

		/* Re-open live devices to avoid underruns. */

		if(SENSITIVE_OUTPUT(ao) && aoopen(ao) < 0)

		{

			/* Will be overwritten by following out123_play() ... */

			ao->errcode = OUT123_DEV_OPEN;

			if(!AOQUIET)

				error("failed re-opening of device after pause");

			return;

		}

		ao->state = play_live;

	}

}

void attribute_align_arg out123_stop(out123_handle *ao)

{

	debug2("[%ld]out123_stop(%p)", (long)getpid(), (void*)ao);

	if(!ao)

		return;

	ao->errcode = 0;

	if(!(ao->state == play_paused || ao->state == play_live))

		return;

#ifndef NOXFERMEM

	if(have_buffer(ao))

		buffer_stop(ao);

	else

#endif

	if(   ao->state == play_live

	  || (ao->state == play_paused && !SENSITIVE_OUTPUT(ao)) )

	{

		if(ao->close && ao->close(ao) && !AOQUIET)

			error("trouble closing device");

	}

	ao->state = play_stopped;

}

size_t attribute_align_arg

out123_play(out123_handle *ao, void *bytes, size_t count)

{

	size_t sum = 0;

	int written;

	debug5( "[%ld]out123_play(%p, %p, %"SIZE_P") (%i)", (long)getpid()

	,	(void*)ao, bytes, (size_p)count, ao ? (int)ao->state : -1 );

	if(!ao)

		return 0;

	ao->errcode = 0;

	/* If paused, automatically continue. Other states are an error. */

	if(ao->state != play_live)

	{

		if(ao->state == play_paused)

			out123_continue(ao);

		if(ao->state != play_live)

		{

			ao->errcode = OUT123_NOT_LIVE;

			return 0;

		}

	}

	/* Ensure that we are writing whole PCM frames. */

	count -= count % ao->framesize;

	if(!count) return 0;

#ifndef NOXFERMEM

	if(have_buffer(ao))

		return buffer_write(ao, bytes, count);

	else

#endif

	do /* Playback in a loop to be able to continue after interruptions. */

	{

		errno = 0;

		written = ao->write(ao, (unsigned char*)bytes, (int)count);

		debug4( "written: %d errno: %i (%s), keep_on=%d"

		,	written, errno, strerror(errno)

		,	ao->flags & OUT123_KEEP_PLAYING );

		if(written >= 0){ sum+=written; count -= written; }

		else if(errno != EINTR)

		{

			ao->errcode = OUT123_DEV_PLAY;

			if(!AOQUIET)

				error1("Error in writing audio (%s?)!", strerror(errno));

			/* If written < 0, this is a serious issue ending this playback round. */

			break;

		}

	} while(count && ao->flags & OUT123_KEEP_PLAYING);

	debug3( "out123_play(%p, %p, ...) = %"SIZE_P

	,	(void*)ao, bytes, (size_p)sum );

	return sum;

}

/* Drop means to flush it down. Quickly. */

void attribute_align_arg out123_drop(out123_handle *ao)

{

	debug2("[%ld]out123_drop(%p)", (long)getpid(), (void*)ao);

	if(!ao)

		return;

	ao->errcode = 0;

#ifndef NOXFERMEM

	if(have_buffer(ao))

		buffer_drop(ao);

	else

#endif

	if(ao->state == play_live)

	{

		if(ao->propflags & OUT123_PROP_LIVE && ao->flush)

			ao->flush(ao);

	}

}

void attribute_align_arg out123_drain(out123_handle *ao)

{

	debug2("[%ld]out123_drain(%p) ", (long)getpid(), (void*)ao);

	if(!ao)

		return;

	ao->errcode = 0;

	/* If paused, automatically continue. */

	if(ao->state != play_live)

	{

		if(ao->state == play_paused)

			out123_continue(ao);

		if(ao->state != play_live)

			return;

	}

#ifndef NOXFERMEM

	if(have_buffer(ao))

		buffer_drain(ao);

	else

#endif

	{

		if(ao->drain)

			ao->drain(ao);

		out123_pause(ao);

	}

}

void attribute_align_arg out123_ndrain(out123_handle *ao, size_t bytes)

{

	debug3("[%ld]out123_ndrain(%p, %"SIZE_P")", (long)getpid(), (void*)ao, (size_p)bytes);

	if(!ao)

		return;

	ao->errcode = 0;

	/* If paused, automatically continue. */

	if(ao->state != play_live)

	{

		if(ao->state == play_paused)

			out123_continue(ao);

		if(ao->state != play_live)

			return;

	}

#ifndef NOXFERMEM

	if(have_buffer(ao))

		buffer_ndrain(ao, bytes);

	else

#endif

	{

		if(ao->drain)

			ao->drain(ao);

		out123_pause(ao);

	}

}

/* A function that does nothing and returns nothing. */

static void builtin_nothing(out123_handle *ao){}

static int test_open(out123_handle *ao)

{

	debug("test_open");

	return OUT123_OK;

}

static int test_get_formats(out123_handle *ao)

{

	debug("test_get_formats");

	return MPG123_ENC_ANY;

}

static int test_write(out123_handle *ao, unsigned char *buf, int len)

{

	debug2("test_write: %i B from %p", len, (void*)buf);

	return len;

}

static void test_flush(out123_handle *ao)

{

	debug("test_flush");

}

static void test_drain(out123_handle *ao)

{

	debug("test_drain");

}

static int test_close(out123_handle *ao)

{

	debug("test_drain");

	return 0;

}

/* Open one of our builtin driver modules. */

static int open_fake_module(out123_handle *ao, const char *driver)

{

	if(!strcmp("test", driver))

	{

		ao->propflags &= ~OUT123_PROP_LIVE;

		ao->open  = test_open;

		ao->get_formats = test_get_formats;

		ao->write = test_write;

		ao->flush = test_flush;

		ao->drain = test_drain;

		ao->close = test_close;

	}

	else

	if(!strcmp("raw", driver))

	{

		ao->propflags &= ~OUT123_PROP_LIVE;

		ao->open  = raw_open;

		ao->get_formats = raw_formats;

		ao->write = wav_write;

		ao->flush = builtin_nothing;

		ao->drain = wav_drain;

		ao->close = raw_close;

	}

	else

	if(!strcmp("wav", driver))

	{

		ao->propflags &= ~OUT123_PROP_LIVE;

		ao->open = wav_open;

		ao->get_formats = wav_formats;

		ao->write = wav_write;

		ao->flush = builtin_nothing;

		ao->drain = wav_drain;

		ao->close = wav_close;

	}

	else

	if(!strcmp("cdr", driver))

	{

		ao->propflags &= ~OUT123_PROP_LIVE;

		ao->open  = cdr_open;

		ao->get_formats = cdr_formats;

		ao->write = wav_write;

		ao->flush = builtin_nothing;

		ao->drain = wav_drain;

		ao->close = raw_close;

	}

	else

	if(!strcmp("au", driver))

	{

		ao->propflags &= ~OUT123_PROP_LIVE;

		ao->open  = au_open;

		ao->get_formats = au_formats;

		ao->write = wav_write;

		ao->flush = builtin_nothing;

		ao->drain = wav_drain;

		ao->close = au_close;

	}

	else return OUT123_ERR;

	return OUT123_OK;

}

/* Check if given output module is loadable and has a working device.

   final flag triggers printing and storing of errors. */

static void check_output_module( out123_handle *ao

,	const char *name, const char *device, int final )

{

	int result;

	debug3("check_output_module %p %p %p", (void*)ao, (void*)device, (void*)ao->device);

	if(AOVERBOSE(1))

		fprintf( stderr, "Trying output module: %s, device: %s\n"

		,	name, ao->device ? ao->device : "<nil>" );

	/* Use internal code. */

	if(open_fake_module(ao, name) == OUT123_OK)

		return;

	/* Open the module, initial check for availability+libraries. */

	ao->module = open_module( "output", name, modverbose(ao, final), ao->bindir);

	if(!ao->module)

		return;

	/* Check if module supports output */

	if(!ao->module->init_output)

	{

		if(final)

			error1("Module '%s' does not support audio output.", name);

		goto check_output_module_cleanup;

	}

	/* Should I do funny stuff with stderr file descriptor instead? */

	if(final)

	{

		if(AOVERBOSE(2))

			fprintf(stderr

			,	"Note: %s is the last output option... showing you any error messages now.\n"

			,	name);

	}

	else ao->auxflags |= OUT123_QUIET; /* Probing, so don't spill stderr with errors. */

	result = ao->module->init_output(ao);

	if(result == 0)

	{ /* Try to open the device. I'm only interested in actually working modules. */

		ao->format = -1;

		result = aoopen(ao);

		debug1("ao->open() = %i", result);

		if(result >= 0) /* Opening worked, close again. */

			ao->close(ao);

		else if(ao->deinit)

			ao->deinit(ao); /* Failed, ensure that cleanup after init_output() occurs. */