src/audio/SDL_audio.c
author Sam Lantinga <slouken@lokigames.com>
Thu, 26 Apr 2001 16:45:43 +0000
changeset 0 74212992fb08
child 21 75a95f82bc1f
permissions -rw-r--r--
Initial revision
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/*
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    SDL - Simple DirectMedia Layer
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    Copyright (C) 1997, 1998, 1999, 2000, 2001  Sam Lantinga
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    This library is free software; you can redistribute it and/or
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    modify it under the terms of the GNU Library General Public
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    License as published by the Free Software Foundation; either
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    version 2 of the License, or (at your option) any later version.
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    This library is distributed in the hope that it will be useful,
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    but WITHOUT ANY WARRANTY; without even the implied warranty of
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    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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    Library General Public License for more details.
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    You should have received a copy of the GNU Library General Public
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    License along with this library; if not, write to the Free
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    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
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    Sam Lantinga
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    slouken@devolution.com
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*/
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#ifdef SAVE_RCSID
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static char rcsid =
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 "@(#) $Id$";
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#endif
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/* Allow access to a raw mixing buffer */
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include "SDL.h"
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#include "SDL_audio.h"
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#include "SDL_timer.h"
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#include "SDL_error.h"
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#include "SDL_audio_c.h"
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#include "SDL_audiomem.h"
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#include "SDL_sysaudio.h"
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/* Available audio drivers */
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static AudioBootStrap *bootstrap[] = {
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#if defined(unix) && \
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   !defined(linux) && !defined(__FreeBSD__) && !defined(__CYGWIN32__) \
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   && !defined(__bsdi__)
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	&AUDIO_bootstrap,
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#endif
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#ifdef OSS_SUPPORT
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	&DSP_bootstrap,
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	&DMA_bootstrap,
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#endif
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#ifdef ALSA_SUPPORT
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	&ALSA_bootstrap,
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#endif
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#ifdef ARTSC_SUPPORT
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	&ARTSC_bootstrap,
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#endif
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#ifdef ESD_SUPPORT
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	&ESD_bootstrap,
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#endif
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#ifdef NAS_SUPPORT
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	&NAS_bootstrap,
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#endif
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#ifdef ENABLE_DIRECTX
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	&DSOUND_bootstrap,
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#endif
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#ifdef ENABLE_WINDIB
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	&WAVEOUT_bootstrap,
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#endif
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#ifdef __BEOS__
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	&BAUDIO_bootstrap,
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#endif
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#if defined(macintosh) || TARGET_API_MAC_CARBON
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	&SNDMGR_bootstrap,
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#endif
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#ifdef _AIX
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	&Paud_bootstrap,
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#endif
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	NULL
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};
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SDL_AudioDevice *current_audio = NULL;
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/* Various local functions */
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int SDL_AudioInit(const char *driver_name);
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void SDL_AudioQuit(void);
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/* The general mixing thread function */
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int SDL_RunAudio(void *audiop)
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{
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	SDL_AudioDevice *audio = (SDL_AudioDevice *)audiop;
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	Uint8 *stream;
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	int    stream_len;
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	void  *udata;
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	void (*fill)(void *userdata,Uint8 *stream, int len);
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	int    silence;
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	/* Perform any thread setup */
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	if ( audio->ThreadInit ) {
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		audio->ThreadInit(audio);
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	}
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	audio->threadid = SDL_ThreadID();
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	/* Set up the mixing function */
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	fill  = audio->spec.callback;
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	udata = audio->spec.userdata;
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	if ( audio->convert.needed ) {
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		if ( audio->convert.src_format == AUDIO_U8 ) {
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			silence = 0x80;
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		} else {
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			silence = 0;
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		}
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		stream_len = audio->convert.len;
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	} else {
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		silence = audio->spec.silence;
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		stream_len = audio->spec.size;
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	}
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	stream = audio->fake_stream;
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	/* Loop, filling the audio buffers */
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	while ( audio->enabled ) {
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		/* Wait for new current buffer to finish playing */
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		if ( stream == audio->fake_stream ) {
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			SDL_Delay((audio->spec.samples*1000)/audio->spec.freq);
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		} else {
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			audio->WaitAudio(audio);
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		}
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		/* Fill the current buffer with sound */
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		if ( audio->convert.needed ) {
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			/* The buffer may not be allocated yet */
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			if ( audio->convert.buf ) {
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				stream = audio->convert.buf;
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			} else {
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				continue;
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			}
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		} else {
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			stream = audio->GetAudioBuf(audio);
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			if ( stream == NULL ) {
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				stream = audio->fake_stream;
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			}
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		}
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		memset(stream, silence, stream_len);
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		if ( ! audio->paused ) {
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			SDL_mutexP(audio->mixer_lock);
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			(*fill)(udata, stream, stream_len);
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			SDL_mutexV(audio->mixer_lock);
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		}
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		/* Convert the audio if necessary */
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		if ( audio->convert.needed ) {
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			SDL_ConvertAudio(&audio->convert);
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			stream = audio->GetAudioBuf(audio);
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			if ( stream == NULL ) {
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				stream = audio->fake_stream;
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			}
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			memcpy(stream, audio->convert.buf,
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			               audio->convert.len_cvt);
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		}
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		/* Ready current buffer for play and change current buffer */
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		if ( stream != audio->fake_stream ) {
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			audio->PlayAudio(audio);
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		}
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	}
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	/* Wait for the audio to drain.. */
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	if ( audio->WaitDone ) {
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		audio->WaitDone(audio);
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	}
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	return(0);
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}
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int SDL_AudioInit(const char *driver_name)
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{
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	SDL_AudioDevice *audio;
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	int i = 0, idx;
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	/* Check to make sure we don't overwrite 'current_audio' */
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	if ( current_audio != NULL ) {
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		SDL_AudioQuit();
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	}
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	/* Select the proper audio driver */
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	audio = NULL;
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	idx = 0;
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#ifdef unix
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	if ( (driver_name == NULL) && (getenv("ESPEAKER") != NULL) ) {
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		/* Ahem, we know that if ESPEAKER is set, user probably wants
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		   to use ESD, but don't start it if it's not already running.
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		   This probably isn't the place to do this, but... Shh! :)
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		 */
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		for ( i=0; bootstrap[i]; ++i ) {
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			if ( strcmp(bootstrap[i]->name, "esd") == 0 ) {
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				const char *esd_no_spawn;
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				/* Don't start ESD if it's not running */
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				esd_no_spawn = getenv("ESD_NO_SPAWN");
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				if ( esd_no_spawn == NULL ) {
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					putenv("ESD_NO_SPAWN=1");
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				}
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				if ( bootstrap[i]->available() ) {
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					audio = bootstrap[i]->create(0);
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					break;
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				}
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#ifdef linux	/* No unsetenv() on most platforms */
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				if ( esd_no_spawn == NULL ) {
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					unsetenv("ESD_NO_SPAWN");
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				}
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#endif
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			}
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		}
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	}
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#endif /* unix */
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	if ( audio == NULL ) {
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		if ( driver_name != NULL ) {
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#if 0	/* This will be replaced with a better driver selection API */
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			if ( strrchr(driver_name, ':') != NULL ) {
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				idx = atoi(strrchr(driver_name, ':')+1);
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			}
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#endif
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			for ( i=0; bootstrap[i]; ++i ) {
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				if (strncmp(bootstrap[i]->name, driver_name,
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				            strlen(bootstrap[i]->name)) == 0) {
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					if ( bootstrap[i]->available() ) {
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						audio=bootstrap[i]->create(idx);
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						break;
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					}
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				}
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			}
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		} else {
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			for ( i=0; bootstrap[i]; ++i ) {
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				if ( bootstrap[i]->available() ) {
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					audio = bootstrap[i]->create(idx);
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					if ( audio != NULL ) {
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						break;
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					}
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				}
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			}
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		}
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		if ( audio == NULL ) {
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			SDL_SetError("No available audio device");
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#if 0 /* Don't fail SDL_Init() if audio isn't available.
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         SDL_OpenAudio() will handle it at that point.  *sigh*
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       */
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			return(-1);
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#endif
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		}
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	}
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	current_audio = audio;
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	if ( current_audio ) {
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		current_audio->name = bootstrap[i]->name;
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	}
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	return(0);
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}
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char *SDL_AudioDriverName(char *namebuf, int maxlen)
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{
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	if ( current_audio != NULL ) {
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		strncpy(namebuf, current_audio->name, maxlen-1);
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		namebuf[maxlen-1] = '\0';
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		return(namebuf);
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	}
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	return(NULL);
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}
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int SDL_OpenAudio(SDL_AudioSpec *desired, SDL_AudioSpec *obtained)
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{
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	SDL_AudioDevice *audio;
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	/* Start up the audio driver, if necessary */
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	if ( ! current_audio ) {
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		if ( (SDL_InitSubSystem(SDL_INIT_AUDIO) < 0) ||
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		     (current_audio == NULL) ) {
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			return(-1);
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		}
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	}
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	audio = current_audio;
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	/* Verify some parameters */
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	if ( desired->callback == NULL ) {
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		SDL_SetError("SDL_OpenAudio() passed a NULL callback");
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		return(-1);
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	}
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	switch ( desired->channels ) {
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	    case 1:	/* Mono */
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	    case 2:	/* Stereo */
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		break;
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	    default:
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		SDL_SetError("1 (mono) and 2 (stereo) channels supported");
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		return(-1);
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	}
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#ifdef macintosh
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	/* FIXME: Need to implement PPC interrupt asm for SDL_LockAudio() */
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#else
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	/* Create a semaphore for locking the sound buffers */
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	audio->mixer_lock = SDL_CreateMutex();
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	if ( audio->mixer_lock == NULL ) {
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		SDL_SetError("Couldn't create mixer lock");
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		SDL_CloseAudio();
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		return(-1);
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	}
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#endif
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	/* Calculate the silence and size of the audio specification */
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	SDL_CalculateAudioSpec(desired);
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	/* Open the audio subsystem */
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	memcpy(&audio->spec, desired, sizeof(audio->spec));
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	audio->convert.needed = 0;
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	audio->enabled = 1;
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	audio->paused  = 1;
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	audio->opened = audio->OpenAudio(audio, &audio->spec)+1;
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	if ( ! audio->opened ) {
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		SDL_CloseAudio();
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		return(-1);
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	}
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	/* If the audio driver changes the buffer size, accept it */
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	if ( audio->spec.samples != desired->samples ) {
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		desired->samples = audio->spec.samples;
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		SDL_CalculateAudioSpec(desired);
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	}
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	/* Allocate a fake audio memory buffer */
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	audio->fake_stream = SDL_AllocAudioMem(audio->spec.size);
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	if ( audio->fake_stream == NULL ) {
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		SDL_CloseAudio();
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		SDL_OutOfMemory();
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		return(-1);
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	}
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	/* See if we need to do any conversion */
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	if ( memcmp(desired, &audio->spec, sizeof(audio->spec)) == 0 ) {
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		/* Just copy over the desired audio specification */
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		if ( obtained != NULL ) {
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			memcpy(obtained, &audio->spec, sizeof(audio->spec));
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		}
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	} else {
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		/* Copy over the audio specification if possible */
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		if ( obtained != NULL ) {
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			memcpy(obtained, &audio->spec, sizeof(audio->spec));
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		} else {
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			/* Build an audio conversion block */
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			if ( SDL_BuildAudioCVT(&audio->convert,
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				desired->format, desired->channels,
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						desired->freq,
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				audio->spec.format, audio->spec.channels,
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						audio->spec.freq) < 0 ) {
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				SDL_CloseAudio();
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				return(-1);
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			}
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			if ( audio->convert.needed ) {
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				audio->convert.len = desired->size;
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				audio->convert.buf =(Uint8 *)SDL_AllocAudioMem(
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				   audio->convert.len*audio->convert.len_mult);
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				if ( audio->convert.buf == NULL ) {
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					SDL_CloseAudio();
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					SDL_OutOfMemory();
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					return(-1);
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				}
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			}
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		}
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	}
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	/* Start the audio thread if necessary */
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	switch (audio->opened) {
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		case  1:
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			/* Start the audio thread */
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			audio->thread = SDL_CreateThread(SDL_RunAudio, audio);
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			if ( audio->thread == NULL ) {
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				SDL_CloseAudio();
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				SDL_SetError("Couldn't create audio thread");
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				return(-1);
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			}
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			break;
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		default:
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			/* The audio is now playing */
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			break;
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	}
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	return(0);
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}
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SDL_audiostatus SDL_GetAudioStatus(void)
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{
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	SDL_AudioDevice *audio = current_audio;
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	SDL_audiostatus status;
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   392
	status = SDL_AUDIO_STOPPED;
slouken@0
   393
	if ( audio && audio->enabled ) {
slouken@0
   394
		if ( audio->paused ) {
slouken@0
   395
			status = SDL_AUDIO_PAUSED;
slouken@0
   396
		} else {
slouken@0
   397
			status = SDL_AUDIO_PLAYING;
slouken@0
   398
		}
slouken@0
   399
	}
slouken@0
   400
	return(status);
slouken@0
   401
}
slouken@0
   402
slouken@0
   403
void SDL_PauseAudio (int pause_on)
slouken@0
   404
{
slouken@0
   405
	SDL_AudioDevice *audio = current_audio;
slouken@0
   406
slouken@0
   407
	if ( audio ) {
slouken@0
   408
		audio->paused = pause_on;
slouken@0
   409
	}
slouken@0
   410
}
slouken@0
   411
slouken@0
   412
void SDL_LockAudio (void)
slouken@0
   413
{
slouken@0
   414
	SDL_AudioDevice *audio = current_audio;
slouken@0
   415
slouken@0
   416
	/* Obtain a lock on the mixing buffers */
slouken@0
   417
	if ( audio ) {
slouken@0
   418
		if ( audio->thread && (SDL_ThreadID() == audio->threadid) ) {
slouken@0
   419
			return;
slouken@0
   420
		}
slouken@0
   421
		SDL_mutexP(audio->mixer_lock);
slouken@0
   422
	}
slouken@0
   423
}
slouken@0
   424
slouken@0
   425
void SDL_UnlockAudio (void)
slouken@0
   426
{
slouken@0
   427
	SDL_AudioDevice *audio = current_audio;
slouken@0
   428
slouken@0
   429
	/* Release lock on the mixing buffers */
slouken@0
   430
	if ( audio ) {
slouken@0
   431
		if ( audio->thread && (SDL_ThreadID() == audio->threadid) ) {
slouken@0
   432
			return;
slouken@0
   433
		}
slouken@0
   434
		SDL_mutexV(audio->mixer_lock);
slouken@0
   435
	}
slouken@0
   436
}
slouken@0
   437
slouken@0
   438
void SDL_CloseAudio (void)
slouken@0
   439
{
slouken@0
   440
	SDL_QuitSubSystem(SDL_INIT_AUDIO);
slouken@0
   441
}
slouken@0
   442
slouken@0
   443
void SDL_AudioQuit(void)
slouken@0
   444
{
slouken@0
   445
	SDL_AudioDevice *audio = current_audio;
slouken@0
   446
slouken@0
   447
	if ( audio ) {
slouken@0
   448
		audio->enabled = 0;
slouken@0
   449
		if ( audio->thread != NULL ) {
slouken@0
   450
			SDL_WaitThread(audio->thread, NULL);
slouken@0
   451
		}
slouken@0
   452
		if ( audio->mixer_lock != NULL ) {
slouken@0
   453
			SDL_DestroyMutex(audio->mixer_lock);
slouken@0
   454
		}
slouken@0
   455
		if ( audio->fake_stream != NULL ) {
slouken@0
   456
			SDL_FreeAudioMem(audio->fake_stream);
slouken@0
   457
		}
slouken@0
   458
		if ( audio->convert.needed ) {
slouken@0
   459
			SDL_FreeAudioMem(audio->convert.buf);
slouken@0
   460
		}
slouken@0
   461
		if ( audio->opened ) {
slouken@0
   462
			audio->CloseAudio(audio);
slouken@0
   463
			audio->opened = 0;
slouken@0
   464
		}
slouken@0
   465
slouken@0
   466
		/* Free the driver data */
slouken@0
   467
		audio->free(audio);
slouken@0
   468
		current_audio = NULL;
slouken@0
   469
	}
slouken@0
   470
}
slouken@0
   471
slouken@0
   472
#define NUM_FORMATS	6
slouken@0
   473
static int format_idx;
slouken@0
   474
static int format_idx_sub;
slouken@0
   475
static Uint16 format_list[NUM_FORMATS][NUM_FORMATS] = {
slouken@0
   476
 { AUDIO_U8, AUDIO_S8, AUDIO_S16LSB, AUDIO_S16MSB, AUDIO_U16LSB, AUDIO_U16MSB },
slouken@0
   477
 { AUDIO_S8, AUDIO_U8, AUDIO_S16LSB, AUDIO_S16MSB, AUDIO_U16LSB, AUDIO_U16MSB },
slouken@0
   478
 { AUDIO_S16LSB, AUDIO_S16MSB, AUDIO_U16LSB, AUDIO_U16MSB, AUDIO_U8, AUDIO_S8 },
slouken@0
   479
 { AUDIO_S16MSB, AUDIO_S16LSB, AUDIO_U16MSB, AUDIO_U16LSB, AUDIO_U8, AUDIO_S8 },
slouken@0
   480
 { AUDIO_U16LSB, AUDIO_U16MSB, AUDIO_S16LSB, AUDIO_S16MSB, AUDIO_U8, AUDIO_S8 },
slouken@0
   481
 { AUDIO_U16MSB, AUDIO_U16LSB, AUDIO_S16MSB, AUDIO_S16LSB, AUDIO_U8, AUDIO_S8 },
slouken@0
   482
};
slouken@0
   483
slouken@0
   484
Uint16 SDL_FirstAudioFormat(Uint16 format)
slouken@0
   485
{
slouken@0
   486
	for ( format_idx=0; format_idx < NUM_FORMATS; ++format_idx ) {
slouken@0
   487
		if ( format_list[format_idx][0] == format ) {
slouken@0
   488
			break;
slouken@0
   489
		}
slouken@0
   490
	}
slouken@0
   491
	format_idx_sub = 0;
slouken@0
   492
	return(SDL_NextAudioFormat());
slouken@0
   493
}
slouken@0
   494
slouken@0
   495
Uint16 SDL_NextAudioFormat(void)
slouken@0
   496
{
slouken@0
   497
	if ( (format_idx == NUM_FORMATS) || (format_idx_sub == NUM_FORMATS) ) {
slouken@0
   498
		return(0);
slouken@0
   499
	}
slouken@0
   500
	return(format_list[format_idx][format_idx_sub++]);
slouken@0
   501
}
slouken@0
   502
slouken@0
   503
void SDL_CalculateAudioSpec(SDL_AudioSpec *spec)
slouken@0
   504
{
slouken@0
   505
	switch (spec->format) {
slouken@0
   506
		case AUDIO_U8:
slouken@0
   507
			spec->silence = 0x80;
slouken@0
   508
			break;
slouken@0
   509
		default:
slouken@0
   510
			spec->silence = 0x00;
slouken@0
   511
			break;
slouken@0
   512
	}
slouken@0
   513
	spec->size = (spec->format&0xFF)/8;
slouken@0
   514
	spec->size *= spec->channels;
slouken@0
   515
	spec->size *= spec->samples;
slouken@0
   516
}