audio/sdlaudio.c - third_party/qemu - Git at Google

 /*
  * QEMU SDL audio driver
  *
  * Copyright (c) 2004-2005 Vassili Karpov (malc)
  *
  * 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.
  *
  * 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.
  */

 #include "qemu/osdep.h"
 #include <SDL.h>
 #include <SDL_thread.h>
 #include "qemu/module.h"
 #include "audio.h"

 #ifndef _WIN32
 #ifdef __sun__
 #define _POSIX_PTHREAD_SEMANTICS 1
 #elif defined(__OpenBSD__) || defined(__FreeBSD__) || defined(__DragonFly__)
 #include <pthread.h>
 #endif
 #endif

 #define AUDIO_CAP "sdl"
 #include "audio_int.h"

 typedef struct SDLVoiceOut {
     HWVoiceOut hw;
     int exit;
     int initialized;
     Audiodev *dev;
     SDL_AudioDeviceID devid;
 } SDLVoiceOut;

 typedef struct SDLVoiceIn {
     HWVoiceIn hw;
     int exit;
     int initialized;
     Audiodev *dev;
     SDL_AudioDeviceID devid;
 } SDLVoiceIn;

 static void GCC_FMT_ATTR (1, 2) sdl_logerr (const char *fmt, ...)
 {
     va_list ap;

     va_start (ap, fmt);
     AUD_vlog (AUDIO_CAP, fmt, ap);
     va_end (ap);

     AUD_log (AUDIO_CAP, "Reason: %s\n", SDL_GetError ());
 }

 static int aud_to_sdlfmt (AudioFormat fmt)
 {
     switch (fmt) {
     case AUDIO_FORMAT_S8:
         return AUDIO_S8;

     case AUDIO_FORMAT_U8:
         return AUDIO_U8;

     case AUDIO_FORMAT_S16:
         return AUDIO_S16LSB;

     case AUDIO_FORMAT_U16:
         return AUDIO_U16LSB;

     case AUDIO_FORMAT_S32:
         return AUDIO_S32LSB;

     /* no unsigned 32-bit support in SDL */

     case AUDIO_FORMAT_F32:
         return AUDIO_F32LSB;

     default:
         dolog ("Internal logic error: Bad audio format %d\n", fmt);
 #ifdef DEBUG_AUDIO
         abort ();
 #endif
         return AUDIO_U8;
     }
 }

 static int sdl_to_audfmt(int sdlfmt, AudioFormat *fmt, int *endianness)
 {
     switch (sdlfmt) {
     case AUDIO_S8:
         *endianness = 0;
         *fmt = AUDIO_FORMAT_S8;
         break;

     case AUDIO_U8:
         *endianness = 0;
         *fmt = AUDIO_FORMAT_U8;
         break;

     case AUDIO_S16LSB:
         *endianness = 0;
         *fmt = AUDIO_FORMAT_S16;
         break;

     case AUDIO_U16LSB:
         *endianness = 0;
         *fmt = AUDIO_FORMAT_U16;
         break;

     case AUDIO_S16MSB:
         *endianness = 1;
         *fmt = AUDIO_FORMAT_S16;
         break;

     case AUDIO_U16MSB:
         *endianness = 1;
         *fmt = AUDIO_FORMAT_U16;
         break;

     case AUDIO_S32LSB:
         *endianness = 0;
         *fmt = AUDIO_FORMAT_S32;
         break;

     case AUDIO_S32MSB:
         *endianness = 1;
         *fmt = AUDIO_FORMAT_S32;
         break;

     case AUDIO_F32LSB:
         *endianness = 0;
         *fmt = AUDIO_FORMAT_F32;
         break;

     case AUDIO_F32MSB:
         *endianness = 1;
         *fmt = AUDIO_FORMAT_F32;
         break;

     default:
         dolog ("Unrecognized SDL audio format %d\n", sdlfmt);
         return -1;
     }

     return 0;
 }

 static SDL_AudioDeviceID sdl_open(SDL_AudioSpec *req, SDL_AudioSpec *obt,
                                   int rec)
 {
     SDL_AudioDeviceID devid;
 #ifndef _WIN32
     int err;
     sigset_t new, old;

     /* Make sure potential threads created by SDL don't hog signals.  */
     err = sigfillset (&new);
     if (err) {
         dolog ("sdl_open: sigfillset failed: %s\n", strerror (errno));
         return 0;
     }
     err = pthread_sigmask (SIG_BLOCK, &new, &old);
     if (err) {
         dolog ("sdl_open: pthread_sigmask failed: %s\n", strerror (err));
         return 0;
     }
 #endif

     devid = SDL_OpenAudioDevice(NULL, rec, req, obt, 0);
     if (!devid) {
         sdl_logerr("SDL_OpenAudioDevice for %s failed\n",
                    rec ? "recording" : "playback");
     }

 #ifndef _WIN32
     err = pthread_sigmask (SIG_SETMASK, &old, NULL);
     if (err) {
         dolog ("sdl_open: pthread_sigmask (restore) failed: %s\n",
                strerror (errno));
         /* We have failed to restore original signal mask, all bets are off,
            so exit the process */
         exit (EXIT_FAILURE);
     }
 #endif
     return devid;
 }

 static void sdl_close_out(SDLVoiceOut *sdl)
 {
     if (sdl->initialized) {
         SDL_LockAudioDevice(sdl->devid);
         sdl->exit = 1;
         SDL_UnlockAudioDevice(sdl->devid);
         SDL_PauseAudioDevice(sdl->devid, 1);
         sdl->initialized = 0;
     }
     if (sdl->devid) {
         SDL_CloseAudioDevice(sdl->devid);
         sdl->devid = 0;
     }
 }

 static void sdl_callback_out(void *opaque, Uint8 *buf, int len)
 {
     SDLVoiceOut *sdl = opaque;
     HWVoiceOut *hw = &sdl->hw;

     if (!sdl->exit) {

         /* dolog("callback_out: len=%d avail=%zu\n", len, hw->pending_emul); */

         while (hw->pending_emul && len) {
             size_t write_len, start;

             start = audio_ring_posb(hw->pos_emul, hw->pending_emul,
                                     hw->size_emul);
             assert(start < hw->size_emul);

             write_len = MIN(MIN(hw->pending_emul, len),
                             hw->size_emul - start);

             memcpy(buf, hw->buf_emul + start, write_len);
             hw->pending_emul -= write_len;
             len -= write_len;
             buf += write_len;
         }
     }

     /* clear remaining buffer that we couldn't fill with data */
     if (len) {
         audio_pcm_info_clear_buf(&hw->info, buf,
                                  len / hw->info.bytes_per_frame);
     }
 }

 static void sdl_close_in(SDLVoiceIn *sdl)
 {
     if (sdl->initialized) {
         SDL_LockAudioDevice(sdl->devid);
         sdl->exit = 1;
         SDL_UnlockAudioDevice(sdl->devid);
         SDL_PauseAudioDevice(sdl->devid, 1);
         sdl->initialized = 0;
     }
     if (sdl->devid) {
         SDL_CloseAudioDevice(sdl->devid);
         sdl->devid = 0;
     }
 }

 static void sdl_callback_in(void *opaque, Uint8 *buf, int len)
 {
     SDLVoiceIn *sdl = opaque;
     HWVoiceIn *hw = &sdl->hw;

     if (sdl->exit) {
         return;
     }

     /* dolog("callback_in: len=%d pending=%zu\n", len, hw->pending_emul); */

     while (hw->pending_emul < hw->size_emul && len) {
         size_t read_len = MIN(len, MIN(hw->size_emul - hw->pos_emul,
                                        hw->size_emul - hw->pending_emul));

         memcpy(hw->buf_emul + hw->pos_emul, buf, read_len);

         hw->pending_emul += read_len;
         hw->pos_emul = (hw->pos_emul + read_len) % hw->size_emul;
         len -= read_len;
         buf += read_len;
     }
 }

 #define SDL_WRAPPER_FUNC(name, ret_type, args_decl, args, dir) \
     static ret_type glue(sdl_, name)args_decl                  \
     {                                                          \
         ret_type ret;                                          \
         glue(SDLVoice, dir) *sdl = (glue(SDLVoice, dir) *)hw;  \
                                                                \
         SDL_LockAudioDevice(sdl->devid);                       \
         ret = glue(audio_generic_, name)args;                  \
         SDL_UnlockAudioDevice(sdl->devid);                     \
                                                                \
         return ret;                                            \
     }

 #define SDL_WRAPPER_VOID_FUNC(name, args_decl, args, dir)      \
     static void glue(sdl_, name)args_decl                      \
     {                                                          \
         glue(SDLVoice, dir) *sdl = (glue(SDLVoice, dir) *)hw;  \
                                                                \
         SDL_LockAudioDevice(sdl->devid);                       \
         glue(audio_generic_, name)args;                        \
         SDL_UnlockAudioDevice(sdl->devid);                     \
     }

 SDL_WRAPPER_FUNC(buffer_get_free, size_t, (HWVoiceOut *hw), (hw), Out)
 SDL_WRAPPER_FUNC(get_buffer_out, void *, (HWVoiceOut *hw, size_t *size),
                  (hw, size), Out)
 SDL_WRAPPER_FUNC(put_buffer_out, size_t,
                  (HWVoiceOut *hw, void *buf, size_t size), (hw, buf, size), Out)
 SDL_WRAPPER_FUNC(write, size_t,
                  (HWVoiceOut *hw, void *buf, size_t size), (hw, buf, size), Out)
 SDL_WRAPPER_FUNC(read, size_t, (HWVoiceIn *hw, void *buf, size_t size),
                  (hw, buf, size), In)
 SDL_WRAPPER_FUNC(get_buffer_in, void *, (HWVoiceIn *hw, size_t *size),
                  (hw, size), In)
 SDL_WRAPPER_VOID_FUNC(put_buffer_in, (HWVoiceIn *hw, void *buf, size_t size),
                       (hw, buf, size), In)
 #undef SDL_WRAPPER_FUNC
 #undef SDL_WRAPPER_VOID_FUNC

 static void sdl_fini_out(HWVoiceOut *hw)
 {
     SDLVoiceOut *sdl = (SDLVoiceOut *)hw;

     sdl_close_out(sdl);
 }

 static int sdl_init_out(HWVoiceOut *hw, struct audsettings *as,
                         void *drv_opaque)
 {
     SDLVoiceOut *sdl = (SDLVoiceOut *)hw;
     SDL_AudioSpec req, obt;
     int endianness;
     int err;
     AudioFormat effective_fmt;
     Audiodev *dev = drv_opaque;
     AudiodevSdlPerDirectionOptions *spdo = dev->u.sdl.out;
     struct audsettings obt_as;

     req.freq = as->freq;
     req.format = aud_to_sdlfmt (as->fmt);
     req.channels = as->nchannels;
     /* SDL samples are QEMU frames */
     req.samples = audio_buffer_frames(
         qapi_AudiodevSdlPerDirectionOptions_base(spdo), as, 11610);
     req.callback = sdl_callback_out;
     req.userdata = sdl;

     sdl->dev = dev;
     sdl->devid = sdl_open(&req, &obt, 0);
     if (!sdl->devid) {
         return -1;
     }

     err = sdl_to_audfmt(obt.format, &effective_fmt, &endianness);
     if (err) {
         sdl_close_out(sdl);
         return -1;
     }

     obt_as.freq = obt.freq;
     obt_as.nchannels = obt.channels;
     obt_as.fmt = effective_fmt;
     obt_as.endianness = endianness;

     audio_pcm_init_info (&hw->info, &obt_as);
     hw->samples = (spdo->has_buffer_count ? spdo->buffer_count : 4) *
         obt.samples;

     sdl->initialized = 1;
     sdl->exit = 0;
     return 0;
 }

 static void sdl_enable_out(HWVoiceOut *hw, bool enable)
 {
     SDLVoiceOut *sdl = (SDLVoiceOut *)hw;

     SDL_PauseAudioDevice(sdl->devid, !enable);
 }

 static void sdl_fini_in(HWVoiceIn *hw)
 {
     SDLVoiceIn *sdl = (SDLVoiceIn *)hw;

     sdl_close_in(sdl);
 }

 static int sdl_init_in(HWVoiceIn *hw, audsettings *as, void *drv_opaque)
 {
     SDLVoiceIn *sdl = (SDLVoiceIn *)hw;
     SDL_AudioSpec req, obt;
     int endianness;
     int err;
     AudioFormat effective_fmt;
     Audiodev *dev = drv_opaque;
     AudiodevSdlPerDirectionOptions *spdo = dev->u.sdl.in;
     struct audsettings obt_as;

     req.freq = as->freq;
     req.format = aud_to_sdlfmt(as->fmt);
     req.channels = as->nchannels;
     /* SDL samples are QEMU frames */
     req.samples = audio_buffer_frames(
         qapi_AudiodevSdlPerDirectionOptions_base(spdo), as, 11610);
     req.callback = sdl_callback_in;
     req.userdata = sdl;

     sdl->dev = dev;
     sdl->devid = sdl_open(&req, &obt, 1);
     if (!sdl->devid) {
         return -1;
     }

     err = sdl_to_audfmt(obt.format, &effective_fmt, &endianness);
     if (err) {
         sdl_close_in(sdl);
         return -1;
     }

     obt_as.freq = obt.freq;
     obt_as.nchannels = obt.channels;
     obt_as.fmt = effective_fmt;
     obt_as.endianness = endianness;

     audio_pcm_init_info(&hw->info, &obt_as);
     hw->samples = (spdo->has_buffer_count ? spdo->buffer_count : 4) *
         obt.samples;
     hw->size_emul = hw->samples * hw->info.bytes_per_frame;
     hw->buf_emul = g_malloc(hw->size_emul);
     hw->pos_emul = hw->pending_emul = 0;

     sdl->initialized = 1;
     sdl->exit = 0;
     return 0;
 }

 static void sdl_enable_in(HWVoiceIn *hw, bool enable)
 {
     SDLVoiceIn *sdl = (SDLVoiceIn *)hw;

     SDL_PauseAudioDevice(sdl->devid, !enable);
 }

 static void *sdl_audio_init(Audiodev *dev)
 {
     if (SDL_InitSubSystem (SDL_INIT_AUDIO)) {
         sdl_logerr ("SDL failed to initialize audio subsystem\n");
         return NULL;
     }

     return dev;
 }

 static void sdl_audio_fini (void *opaque)
 {
     SDL_QuitSubSystem (SDL_INIT_AUDIO);
 }

 static struct audio_pcm_ops sdl_pcm_ops = {
     .init_out = sdl_init_out,
     .fini_out = sdl_fini_out,
   /* wrapper for audio_generic_write */
     .write    = sdl_write,
   /* wrapper for audio_generic_buffer_get_free */
     .buffer_get_free = sdl_buffer_get_free,
   /* wrapper for audio_generic_get_buffer_out */
     .get_buffer_out = sdl_get_buffer_out,
   /* wrapper for audio_generic_put_buffer_out */
     .put_buffer_out = sdl_put_buffer_out,
     .enable_out = sdl_enable_out,
     .init_in = sdl_init_in,
     .fini_in = sdl_fini_in,
   /* wrapper for audio_generic_read */
     .read = sdl_read,
   /* wrapper for audio_generic_get_buffer_in */
     .get_buffer_in = sdl_get_buffer_in,
   /* wrapper for audio_generic_put_buffer_in */
     .put_buffer_in = sdl_put_buffer_in,
     .enable_in = sdl_enable_in,
 };

 static struct audio_driver sdl_audio_driver = {
     .name           = "sdl",
     .descr          = "SDL http://www.libsdl.org",
     .init           = sdl_audio_init,
     .fini           = sdl_audio_fini,
     .pcm_ops        = &sdl_pcm_ops,
     .can_be_default = 1,
     .max_voices_out = INT_MAX,
     .max_voices_in  = INT_MAX,
     .voice_size_out = sizeof(SDLVoiceOut),
     .voice_size_in  = sizeof(SDLVoiceIn),
 };

 static void register_audio_sdl(void)
 {
     audio_driver_register(&sdl_audio_driver);
 }
 type_init(register_audio_sdl);
	/*
	* QEMU SDL audio driver
	*
	* Copyright (c) 2004-2005 Vassili Karpov (malc)
	*
	* 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.
	*
	* 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.
	*/

	#include "qemu/osdep.h"
	#include <SDL.h>
	#include <SDL_thread.h>
	#include "qemu/module.h"
	#include "audio.h"

	#ifndef _WIN32
	#ifdef __sun__
	#define _POSIX_PTHREAD_SEMANTICS 1
	#elif defined(__OpenBSD__) \|\| defined(__FreeBSD__) \|\| defined(__DragonFly__)
	#include <pthread.h>
	#endif
	#endif

	#define AUDIO_CAP "sdl"
	#include "audio_int.h"

	typedef struct SDLVoiceOut {
	HWVoiceOut hw;
	int exit;
	int initialized;
	Audiodev *dev;
	SDL_AudioDeviceID devid;
	} SDLVoiceOut;

	typedef struct SDLVoiceIn {
	HWVoiceIn hw;
	int exit;
	int initialized;
	Audiodev *dev;
	SDL_AudioDeviceID devid;
	} SDLVoiceIn;

	static void GCC_FMT_ATTR (1, 2) sdl_logerr (const char *fmt, ...)
	{
	va_list ap;

	va_start (ap, fmt);
	AUD_vlog (AUDIO_CAP, fmt, ap);
	va_end (ap);

	AUD_log (AUDIO_CAP, "Reason: %s\n", SDL_GetError ());
	}

	static int aud_to_sdlfmt (AudioFormat fmt)
	{
	switch (fmt) {
	case AUDIO_FORMAT_S8:
	return AUDIO_S8;

	case AUDIO_FORMAT_U8:
	return AUDIO_U8;

	case AUDIO_FORMAT_S16:
	return AUDIO_S16LSB;

	case AUDIO_FORMAT_U16:
	return AUDIO_U16LSB;

	case AUDIO_FORMAT_S32:
	return AUDIO_S32LSB;

	/* no unsigned 32-bit support in SDL */

	case AUDIO_FORMAT_F32:
	return AUDIO_F32LSB;

	default:
	dolog ("Internal logic error: Bad audio format %d\n", fmt);
	#ifdef DEBUG_AUDIO
	abort ();
	#endif
	return AUDIO_U8;
	}
	}

	static int sdl_to_audfmt(int sdlfmt, AudioFormat fmt, int endianness)
	{
	switch (sdlfmt) {
	case AUDIO_S8:
	*endianness = 0;
	*fmt = AUDIO_FORMAT_S8;
	break;

	case AUDIO_U8:
	*endianness = 0;
	*fmt = AUDIO_FORMAT_U8;
	break;

	case AUDIO_S16LSB:
	*endianness = 0;
	*fmt = AUDIO_FORMAT_S16;
	break;

	case AUDIO_U16LSB:
	*endianness = 0;
	*fmt = AUDIO_FORMAT_U16;
	break;

	case AUDIO_S16MSB:
	*endianness = 1;
	*fmt = AUDIO_FORMAT_S16;
	break;

	case AUDIO_U16MSB:
	*endianness = 1;
	*fmt = AUDIO_FORMAT_U16;
	break;

	case AUDIO_S32LSB:
	*endianness = 0;
	*fmt = AUDIO_FORMAT_S32;
	break;

	case AUDIO_S32MSB:
	*endianness = 1;
	*fmt = AUDIO_FORMAT_S32;
	break;

	case AUDIO_F32LSB:
	*endianness = 0;
	*fmt = AUDIO_FORMAT_F32;
	break;

	case AUDIO_F32MSB:
	*endianness = 1;
	*fmt = AUDIO_FORMAT_F32;
	break;

	default:
	dolog ("Unrecognized SDL audio format %d\n", sdlfmt);
	return -1;
	}

	return 0;
	}

	static SDL_AudioDeviceID sdl_open(SDL_AudioSpec req, SDL_AudioSpec obt,
	int rec)
	{
	SDL_AudioDeviceID devid;
	#ifndef _WIN32
	int err;
	sigset_t new, old;

	/* Make sure potential threads created by SDL don't hog signals. */
	err = sigfillset (&new);
	if (err) {
	dolog ("sdl_open: sigfillset failed: %s\n", strerror (errno));
	return 0;
	}
	err = pthread_sigmask (SIG_BLOCK, &new, &old);
	if (err) {
	dolog ("sdl_open: pthread_sigmask failed: %s\n", strerror (err));
	return 0;
	}
	#endif

	devid = SDL_OpenAudioDevice(NULL, rec, req, obt, 0);
	if (!devid) {
	sdl_logerr("SDL_OpenAudioDevice for %s failed\n",
	rec ? "recording" : "playback");
	}

	#ifndef _WIN32
	err = pthread_sigmask (SIG_SETMASK, &old, NULL);
	if (err) {
	dolog ("sdl_open: pthread_sigmask (restore) failed: %s\n",
	strerror (errno));
	/* We have failed to restore original signal mask, all bets are off,
	so exit the process */
	exit (EXIT_FAILURE);
	}
	#endif
	return devid;
	}

	static void sdl_close_out(SDLVoiceOut *sdl)
	{
	if (sdl->initialized) {
	SDL_LockAudioDevice(sdl->devid);
	sdl->exit = 1;
	SDL_UnlockAudioDevice(sdl->devid);
	SDL_PauseAudioDevice(sdl->devid, 1);
	sdl->initialized = 0;
	}
	if (sdl->devid) {
	SDL_CloseAudioDevice(sdl->devid);
	sdl->devid = 0;
	}
	}

	static void sdl_callback_out(void opaque, Uint8 buf, int len)
	{
	SDLVoiceOut *sdl = opaque;
	HWVoiceOut *hw = &sdl->hw;

	if (!sdl->exit) {

	/* dolog("callback_out: len=%d avail=%zu\n", len, hw->pending_emul); */

	while (hw->pending_emul && len) {
	size_t write_len, start;

	start = audio_ring_posb(hw->pos_emul, hw->pending_emul,
	hw->size_emul);
	assert(start < hw->size_emul);

	write_len = MIN(MIN(hw->pending_emul, len),
	hw->size_emul - start);

	memcpy(buf, hw->buf_emul + start, write_len);
	hw->pending_emul -= write_len;
	len -= write_len;
	buf += write_len;
	}
	}

	/* clear remaining buffer that we couldn't fill with data */
	if (len) {
	audio_pcm_info_clear_buf(&hw->info, buf,
	len / hw->info.bytes_per_frame);
	}
	}

	static void sdl_close_in(SDLVoiceIn *sdl)
	{
	if (sdl->initialized) {
	SDL_LockAudioDevice(sdl->devid);
	sdl->exit = 1;
	SDL_UnlockAudioDevice(sdl->devid);
	SDL_PauseAudioDevice(sdl->devid, 1);
	sdl->initialized = 0;
	}
	if (sdl->devid) {
	SDL_CloseAudioDevice(sdl->devid);
	sdl->devid = 0;
	}
	}

	static void sdl_callback_in(void opaque, Uint8 buf, int len)
	{
	SDLVoiceIn *sdl = opaque;
	HWVoiceIn *hw = &sdl->hw;

	if (sdl->exit) {
	return;
	}

	/* dolog("callback_in: len=%d pending=%zu\n", len, hw->pending_emul); */

	while (hw->pending_emul < hw->size_emul && len) {
	size_t read_len = MIN(len, MIN(hw->size_emul - hw->pos_emul,
	hw->size_emul - hw->pending_emul));

	memcpy(hw->buf_emul + hw->pos_emul, buf, read_len);

	hw->pending_emul += read_len;
	hw->pos_emul = (hw->pos_emul + read_len) % hw->size_emul;
	len -= read_len;
	buf += read_len;
	}
	}

	#define SDL_WRAPPER_FUNC(name, ret_type, args_decl, args, dir) \
	static ret_type glue(sdl_, name)args_decl \
	{ \
	ret_type ret; \
	glue(SDLVoice, dir) sdl = (glue(SDLVoice, dir) )hw; \
	\
	SDL_LockAudioDevice(sdl->devid); \
	ret = glue(audio_generic_, name)args; \
	SDL_UnlockAudioDevice(sdl->devid); \
	\
	return ret; \
	}

	#define SDL_WRAPPER_VOID_FUNC(name, args_decl, args, dir) \
	static void glue(sdl_, name)args_decl \
	{ \
	glue(SDLVoice, dir) sdl = (glue(SDLVoice, dir) )hw; \
	\
	SDL_LockAudioDevice(sdl->devid); \
	glue(audio_generic_, name)args; \
	SDL_UnlockAudioDevice(sdl->devid); \
	}

	SDL_WRAPPER_FUNC(buffer_get_free, size_t, (HWVoiceOut *hw), (hw), Out)
	SDL_WRAPPER_FUNC(get_buffer_out, void , (HWVoiceOut hw, size_t *size),
	(hw, size), Out)
	SDL_WRAPPER_FUNC(put_buffer_out, size_t,
	(HWVoiceOut hw, void buf, size_t size), (hw, buf, size), Out)
	SDL_WRAPPER_FUNC(write, size_t,
	(HWVoiceOut hw, void buf, size_t size), (hw, buf, size), Out)
	SDL_WRAPPER_FUNC(read, size_t, (HWVoiceIn hw, void buf, size_t size),
	(hw, buf, size), In)
	SDL_WRAPPER_FUNC(get_buffer_in, void , (HWVoiceIn hw, size_t *size),
	(hw, size), In)
	SDL_WRAPPER_VOID_FUNC(put_buffer_in, (HWVoiceIn hw, void buf, size_t size),
	(hw, buf, size), In)
	#undef SDL_WRAPPER_FUNC
	#undef SDL_WRAPPER_VOID_FUNC

	static void sdl_fini_out(HWVoiceOut *hw)
	{
	SDLVoiceOut sdl = (SDLVoiceOut )hw;

	sdl_close_out(sdl);
	}

	static int sdl_init_out(HWVoiceOut hw, struct audsettings as,
	void *drv_opaque)
	{
	SDLVoiceOut sdl = (SDLVoiceOut )hw;
	SDL_AudioSpec req, obt;
	int endianness;
	int err;
	AudioFormat effective_fmt;
	Audiodev *dev = drv_opaque;
	AudiodevSdlPerDirectionOptions *spdo = dev->u.sdl.out;
	struct audsettings obt_as;

	req.freq = as->freq;
	req.format = aud_to_sdlfmt (as->fmt);
	req.channels = as->nchannels;
	/* SDL samples are QEMU frames */
	req.samples = audio_buffer_frames(
	qapi_AudiodevSdlPerDirectionOptions_base(spdo), as, 11610);
	req.callback = sdl_callback_out;
	req.userdata = sdl;

	sdl->dev = dev;
	sdl->devid = sdl_open(&req, &obt, 0);
	if (!sdl->devid) {
	return -1;
	}

	err = sdl_to_audfmt(obt.format, &effective_fmt, &endianness);
	if (err) {
	sdl_close_out(sdl);
	return -1;
	}

	obt_as.freq = obt.freq;
	obt_as.nchannels = obt.channels;
	obt_as.fmt = effective_fmt;
	obt_as.endianness = endianness;

	audio_pcm_init_info (&hw->info, &obt_as);
	hw->samples = (spdo->has_buffer_count ? spdo->buffer_count : 4) *
	obt.samples;

	sdl->initialized = 1;
	sdl->exit = 0;
	return 0;
	}

	static void sdl_enable_out(HWVoiceOut *hw, bool enable)
	{
	SDLVoiceOut sdl = (SDLVoiceOut )hw;

	SDL_PauseAudioDevice(sdl->devid, !enable);
	}

	static void sdl_fini_in(HWVoiceIn *hw)
	{
	SDLVoiceIn sdl = (SDLVoiceIn )hw;

	sdl_close_in(sdl);
	}

	static int sdl_init_in(HWVoiceIn hw, audsettings as, void *drv_opaque)
	{
	SDLVoiceIn sdl = (SDLVoiceIn )hw;
	SDL_AudioSpec req, obt;
	int endianness;
	int err;
	AudioFormat effective_fmt;
	Audiodev *dev = drv_opaque;
	AudiodevSdlPerDirectionOptions *spdo = dev->u.sdl.in;
	struct audsettings obt_as;

	req.freq = as->freq;
	req.format = aud_to_sdlfmt(as->fmt);
	req.channels = as->nchannels;
	/* SDL samples are QEMU frames */
	req.samples = audio_buffer_frames(
	qapi_AudiodevSdlPerDirectionOptions_base(spdo), as, 11610);
	req.callback = sdl_callback_in;
	req.userdata = sdl;

	sdl->dev = dev;
	sdl->devid = sdl_open(&req, &obt, 1);
	if (!sdl->devid) {
	return -1;
	}

	err = sdl_to_audfmt(obt.format, &effective_fmt, &endianness);
	if (err) {
	sdl_close_in(sdl);
	return -1;
	}

	obt_as.freq = obt.freq;
	obt_as.nchannels = obt.channels;
	obt_as.fmt = effective_fmt;
	obt_as.endianness = endianness;

	audio_pcm_init_info(&hw->info, &obt_as);
	hw->samples = (spdo->has_buffer_count ? spdo->buffer_count : 4) *
	obt.samples;
	hw->size_emul = hw->samples * hw->info.bytes_per_frame;
	hw->buf_emul = g_malloc(hw->size_emul);
	hw->pos_emul = hw->pending_emul = 0;

	sdl->initialized = 1;
	sdl->exit = 0;
	return 0;
	}

	static void sdl_enable_in(HWVoiceIn *hw, bool enable)
	{
	SDLVoiceIn sdl = (SDLVoiceIn )hw;

	SDL_PauseAudioDevice(sdl->devid, !enable);
	}

	static void sdl_audio_init(Audiodev dev)
	{
	if (SDL_InitSubSystem (SDL_INIT_AUDIO)) {
	sdl_logerr ("SDL failed to initialize audio subsystem\n");
	return NULL;
	}

	return dev;
	}

	static void sdl_audio_fini (void *opaque)
	{
	SDL_QuitSubSystem (SDL_INIT_AUDIO);
	}

	static struct audio_pcm_ops sdl_pcm_ops = {
	.init_out = sdl_init_out,
	.fini_out = sdl_fini_out,
	/* wrapper for audio_generic_write */
	.write = sdl_write,
	/* wrapper for audio_generic_buffer_get_free */
	.buffer_get_free = sdl_buffer_get_free,
	/* wrapper for audio_generic_get_buffer_out */
	.get_buffer_out = sdl_get_buffer_out,
	/* wrapper for audio_generic_put_buffer_out */
	.put_buffer_out = sdl_put_buffer_out,
	.enable_out = sdl_enable_out,
	.init_in = sdl_init_in,
	.fini_in = sdl_fini_in,
	/* wrapper for audio_generic_read */
	.read = sdl_read,
	/* wrapper for audio_generic_get_buffer_in */
	.get_buffer_in = sdl_get_buffer_in,
	/* wrapper for audio_generic_put_buffer_in */
	.put_buffer_in = sdl_put_buffer_in,
	.enable_in = sdl_enable_in,
	};

	static struct audio_driver sdl_audio_driver = {
	.name = "sdl",
	.descr = "SDL http://www.libsdl.org",
	.init = sdl_audio_init,
	.fini = sdl_audio_fini,
	.pcm_ops = &sdl_pcm_ops,
	.can_be_default = 1,
	.max_voices_out = INT_MAX,
	.max_voices_in = INT_MAX,
	.voice_size_out = sizeof(SDLVoiceOut),
	.voice_size_in = sizeof(SDLVoiceIn),
	};

	static void register_audio_sdl(void)
	{
	audio_driver_register(&sdl_audio_driver);
	}
	type_init(register_audio_sdl);