[PATCH] sndio audio backend for OpenBSD

Brad_Smith · June 13, 2012, 6:36am

Below is a patch for the SDL-1.2 branch to add the sndio audio backend
and disable the old BSD backend on OpenBSD. We’ve had this in the OpenBSD
ports tree over 3 years.

sndio is the sound API used on OpenBSD (going on 8 releases now).

I think I got the autoconf bits right as I had to rewrite that over what is
in the tree for autoconf as it is just some hacked up code for the generated
autoconf script at the moment.

diff -r 9cff1c7c0fff configure.in
— a/configure.in Sun Jun 03 05:03:45 2012 -0400
+++ b/configure.in Wed Jun 13 02:24:26 2012 -0400
@@ -486,6 +486,34 @@
fi
}

+dnl Find Sndio
+CheckSndio()
+{

AC_ARG_ENABLE(sndio,
+AC_HELP_STRING([–enable-sndio], [support the sndio audio API [[default=yes]]]),
```
             , enable_sndioaudio=yes)
```
if test x$enable_audio = xyes -a x$enable_sndioaudio = xyes; then

   AC_CHECK_HEADER(sndio.h, have_sndio_hdr=yes)

   AC_CHECK_LIB(sndio, sio_open, have_sndio_lib=yes)+

```
   AC_MSG_CHECKING(for sndio support)
```
```
   have_sndio=no
```

   if test x$have_sndio_hdr = xyes -a x$have_sndio_lib = xyes; then

```
       have_sndio=yes
```
```
       SNDIO_LIBS="-lsndio"
```
```
   fi
```
```
   AC_MSG_RESULT($have_nas)
```
```
   if test x$have_sndio = xyes; then
```

       AC_DEFINE(SDL_AUDIO_DRIVER_SNDIO)

       SOURCES="$SOURCES $srcdir/src/audio/sndio/*.c"

       EXTRA_LDFLAGS="$EXTRA_LDFLAGS $SNDIO_LIBS"

```
       have_audio=yes
```
```
   fi
```

+}
+
dnl Find PulseAudio
CheckPulseAudio()
{
@@ -2358,6 +2386,7 @@
CheckALSA
CheckARTSC
CheckESD

   CheckSndio
   CheckPulseAudio
   CheckNAS
   CheckX11

@@ -2390,7 +2419,7 @@
SOURCES="$SOURCES $srcdir/src/audio/sun/*.c"
have_audio=yes
;;

```
       netbsd|openbsd)
```

       netbsd)
           AC_DEFINE(SDL_AUDIO_DRIVER_BSD)
           SOURCES="$SOURCES $srcdir/src/audio/bsd/*.c"
           have_audio=yes

diff -r 9cff1c7c0fff include/SDL_config.h.in
— a/include/SDL_config.h.in Sun Jun 03 05:03:45 2012 -0400
+++ b/include/SDL_config.h.in Wed Jun 13 02:24:26 2012 -0400
@@ -182,6 +182,7 @@
#undef SDL_AUDIO_DRIVER_OSS_SOUNDCARD_H
#undef SDL_AUDIO_DRIVER_PAUD
#undef SDL_AUDIO_DRIVER_QNXNTO
+#undef SDL_AUDIO_DRIVER_SNDIO
#undef SDL_AUDIO_DRIVER_SNDMGR
#undef SDL_AUDIO_DRIVER_SUNAUDIO
#undef SDL_AUDIO_DRIVER_WAVEOUT
diff -r 9cff1c7c0fff src/audio/SDL_audio.c
— a/src/audio/SDL_audio.c Sun Jun 03 05:03:45 2012 -0400
+++ b/src/audio/SDL_audio.c Wed Jun 13 02:24:26 2012 -0400
@@ -42,6 +42,9 @@
#if SDL_AUDIO_DRIVER_ALSA
&ALSA_bootstrap,
#endif
+#if SDL_AUDIO_DRIVER_SNDIO

&SNDIO_bootstrap,
+#endif
#if SDL_AUDIO_DRIVER_BSD
&BSD_AUDIO_bootstrap,
#endif
diff -r 9cff1c7c0fff src/audio/SDL_sysaudio.h
— a/src/audio/SDL_sysaudio.h Sun Jun 03 05:03:45 2012 -0400
+++ b/src/audio/SDL_sysaudio.h Wed Jun 13 02:24:26 2012 -0400
@@ -102,6 +102,9 @@
SDL_AudioDevice *(*create)(int devindex);
} AudioBootStrap;

+#if SDL_AUDIO_DRIVER_SNDIO
+extern AudioBootStrap SNDIO_bootstrap;
+#endif
#if SDL_AUDIO_DRIVER_BSD
extern AudioBootStrap BSD_AUDIO_bootstrap;
#endif
diff -r 9cff1c7c0fff src/audio/sndio/SDL_sndioaudio.c
— /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/audio/sndio/SDL_sndioaudio.c Wed Jun 13 02:24:26 2012 -0400
@@ -0,0 +1,286 @@
+/*

- Copyright © 2008 Jacob Meuser
- Permission to use, copy, modify, and distribute this software for any
- purpose with or without fee is hereby granted, provided that the above
- copyright notice and this permission notice appear in all copies.
- THE SOFTWARE IS PROVIDED “AS IS” AND THE AUTHOR DISCLAIMS ALL WARRANTIES
- WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
- MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
- ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
- WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
- ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
- OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/

+#include “SDL_config.h”
+
+/* Allow access to a raw mixing buffer /
+
+#ifdef HAVE_SIGNAL_H
+#include <signal.h>
+#endif
+#include <unistd.h>
+
+#include “SDL_timer.h”
+#include “SDL_audio.h”
+#include “…/SDL_audiomem.h”
+#include “…/SDL_audio_c.h”
+#include “…/SDL_audiodev_c.h”
+#include “SDL_sndioaudio.h”
+
+/ The tag name used by sndio audio /
+#define SNDIO_DRIVER_NAME “sndio”
+
+/ Audio driver functions */
+static int SNDIO_OpenAudio(_THIS, SDL_AudioSpec *spec);
+static void SNDIO_WaitAudio(_THIS);
+static void SNDIO_PlayAudio(_THIS);
+static Uint8 SNDIO_GetAudioBuf(_THIS);
+static void SNDIO_CloseAudio(_THIS);
+
+/ Audio driver bootstrap functions */
+
+static int Audio_Available(void)
+{

struct sio_hdl *this_hdl;
int available = 0;
if ( (this_hdl = sio_open(NULL, SIO_PLAY, 0)) != NULL ) {
```
  sio_close(this_hdl);
```
```
  available = 1;
```
}
return available;
+}

+static void Audio_DeleteDevice(SDL_AudioDevice *device)
+{

SDL_free(device->hidden);
SDL_free(device);
+}

+static SDL_AudioDevice *Audio_CreateDevice(int devindex)
+{

SDL_AudioDevice *this;
/* Initialize all variables that we clean on shutdown */
this = (SDL_AudioDevice *)SDL_malloc(sizeof(SDL_AudioDevice));
if ( this ) {
```
  SDL_memset(this, 0, (sizeof *this));
```

  this->hidden = (struct SDL_PrivateAudioData *)

  		SDL_malloc((sizeof *this->hidden));

}
if ( (this == NULL) || (this->hidden == NULL) ) {
```
  SDL_OutOfMemory();
```
```
  if ( this ) {
```
```
  	SDL_free(this);
```
```
  }
```
```
  return(0);
```
}
SDL_memset(this->hidden, 0, (sizeof *this->hidden));
/* Set the function pointers */
this->OpenAudio = SNDIO_OpenAudio;
this->WaitAudio = SNDIO_WaitAudio;
this->PlayAudio = SNDIO_PlayAudio;
this->GetAudioBuf = SNDIO_GetAudioBuf;
this->CloseAudio = SNDIO_CloseAudio;
this->free = Audio_DeleteDevice;
hdl = NULL;
return this;
+}

+AudioBootStrap SNDIO_bootstrap = {

SNDIO_DRIVER_NAME, “sndio”,
Audio_Available, Audio_CreateDevice
+};

+/* This function waits until it is possible to write a full sound buffer */
+static void SNDIO_WaitAudio(_THIS)
+{

/* Check to see if the thread-parent process is still alive */
{ static int cnt = 0;

  /* Note that this only works with thread implementations

     that use a different process id for each thread.

```
  */
```

  if (parent && (((++cnt)%10) == 0)) { /* Check every 10 loops */

```
  	if ( kill(parent, 0) < 0 ) {
```
```
  		this->enabled = 0;
```
```
  	}
```
```
  }
```
}
+}

+static void SNDIO_PlayAudio(_THIS)
+{

int written;
/* Write the audio data */
written = sio_write(hdl, mixbuf, mixlen);
/* If we couldn’t write, assume fatal error for now */
if ( written == 0 ) {
```
  this->enabled = 0;
```
}
+#ifdef DEBUG_AUDIO
fprintf(stderr, “Wrote %d bytes of audio data\n”, written);
+#endif
+}

+static Uint8 *SNDIO_GetAudioBuf(_THIS)
+{

return(mixbuf);
+}

+static void SNDIO_CloseAudio(_THIS)
+{

if ( mixbuf != NULL ) {
```
  SDL_FreeAudioMem(mixbuf);
```
```
  mixbuf = NULL;
```
}
if ( hdl != NULL ) {
```
  sio_close(hdl);
```
```
  hdl = NULL;
```
}
+}

+static int SNDIO_OpenAudio(_THIS, SDL_AudioSpec *spec)
+{

struct sio_par par, reqpar;
int newrate;
mixbuf = NULL;
if ((hdl = sio_open(NULL, SIO_PLAY, 0)) == NULL) {
```
  SDL_SetError("sio_open() failed");
```
```
  return(-1);
```
}
sio_initpar(&par);
switch (spec->format) {
case AUDIO_S16LSB:
```
  par.bits = 16;
```
```
  par.sig = 1;
```
```
  par.le = 1;
```
```
  break;
```
case AUDIO_S16MSB:
```
  par.bits = 16;
```
```
  par.sig = 1;
```
```
  par.le = 0;
```
```
  break;
```
case AUDIO_S8:
```
  par.bits = 8;
```
```
  par.sig = 1;
```
```
  break;
```
case AUDIO_U16LSB:
```
  par.bits = 16;
```
```
  par.sig = 0;
```
```
  par.le = 1;
```
```
  break;
```
case AUDIO_U16MSB:
```
  par.bits = 16;
```
```
  par.sig = 0;
```
```
  par.le = 0;
```
```
  break;
```
case AUDIO_U8:
```
  par.bits = 8;
```
```
  par.sig = 0;
```
```
  break;
```
default:

  SDL_SetError("SNDIO unknown format");

```
  return(-1);
```
}
par.rate = spec->freq;
par.pchan = spec->channels;
par.round = spec->samples;
par.appbufsz = par.round * 2;
reqpar = par;
if (sio_setpar(hdl, &par) == 0) {
```
  SDL_SetError("sio_setpar() failed");
```
```
  return(-1);
```
}
if (sio_getpar(hdl, &par) == 0) {
```
  SDL_SetError("sio_getpar() failed");
```
```
  return(-1);
```
}
/* if wanted rate not found, find a multiple/factor */
if (par.rate != spec->freq) {
```
  newrate = par.rate;
```

  if ((newrate > spec->freq && newrate % spec->freq != 0) ||

       (newrate < spec->freq && spec->freq % newrate != 0)) {

  	if ((spec->freq < 44100 && 44100 % spec->freq == 0) ||

  	     (spec->freq > 44100 && spec->freq % 44100 == 0)) {

```
  		newrate = 44100;
```
```
  	}
```
```
  }
```
```
  /* only change sample rate */
```
```
  par = reqpar;
```
```
  par.rate = newrate;
```
```
  /* keep same latency */
```

  par.round = spec->samples * par.rate / reqpar.rate;

```
  par.appbufsz = par.round * 2;
```
```
  if (sio_setpar(hdl, &par) == 0) {
```

  	SDL_SetError("sio_setpar() failed");

```
  	return(-1);
```
```
  }
```
}
if (sio_getpar(hdl, &par) == 0) {
```
  SDL_SetError("sio_getpar() failed");
```
```
  return(-1);
```
}
if (par.bits == 16) {
```
  if (par.sig && par.le) {
```
```
  	spec->format = AUDIO_S16LSB;
```
```
  } else if (par.sig && !par.le) {
```
```
  	spec->format = AUDIO_S16MSB;
```
```
  } else if (!par.sig && par.le) {
```
```
  	spec->format = AUDIO_U16LSB;
```
```
  } else 
```
```
  	spec->format = AUDIO_U16MSB;
```
} else if (par.bits == 8) {

  spec->format = par.sig ? AUDIO_S8 : AUDIO_U8;

} else {

  SDL_SetError("SNDIO couldn't configure a suitable format");

```
  return(-1);
```
}
spec->freq = par.rate;
spec->channels = par.pchan;
spec->samples = par.round;
SDL_CalculateAudioSpec(spec);
/* Allocate mixing buffer */
mixlen = spec->size;
mixbuf = (Uint8 *)SDL_AllocAudioMem(mixlen);
if ( mixbuf == NULL ) {
```
  return(-1);
```
}
SDL_memset(mixbuf, spec->silence, spec->size);
/* Get the parent process id (we’re the parent of the audio thread) */
parent = getpid();
if ( sio_start(hdl) == 0 ) {
```
  SDL_SetError("sio_start() failed");
```
```
  return(-1);
```
}
/* We’re ready to rock and roll. */
return(0);
+}
diff -r 9cff1c7c0fff src/audio/sndio/SDL_sndioaudio.h
— /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/audio/sndio/SDL_sndioaudio.h Wed Jun 13 02:24:26 2012 -0400
@@ -0,0 +1,50 @@
+/*
- Permission to use, copy, modify, and distribute this software for any
- purpose with or without fee is hereby granted, provided that the above
- copyright notice and this permission notice appear in all copies.
- THE SOFTWARE IS PROVIDED “AS IS” AND THE AUTHOR DISCLAIMS ALL WARRANTIES
- WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
- MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
- ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
- WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
- ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
- OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/

+#include “SDL_config.h”
+
+#ifndef _SDL_sndioaudio_h
+#define _SDL_sndioaudio_h
+
+#include <sndio.h>
+
+#include “…/SDL_sysaudio.h”
+
+/* Hidden “this” pointer for the video functions */
+#define _THIS SDL_AudioDevice *this
+
+struct SDL_PrivateAudioData {

/* The stream descriptor for the audio device */
struct sio_hdl *hdl;
/* The parent process id, to detect when application quits */
pid_t parent;
/* Raw mixing buffer */
Uint8 *mixbuf;
int mixlen;

+};
+
+/* Old variable names /
+#define stream (this->hidden->stream)
+#define parent (this->hidden->parent)
+#define mixbuf (this->hidden->mixbuf)
+#define mixlen (this->hidden->mixlen)
+#define hdl (this->hidden->hdl)
+
+#endif / _SDL_sndioaudio_h */
+

–
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believed to be clean.

Brad_Smith · July 8, 2012, 3:06am

Still looking for any feedback. I’d like to get this in.On Wed, Jun 13, 2012 at 02:36:59AM -0400, Brad Smith wrote:

Below is a patch for the SDL-1.2 branch to add the sndio audio backend
and disable the old BSD backend on OpenBSD. We’ve had this in the OpenBSD
ports tree over 3 years.

sndio is the sound API used on OpenBSD (going on 8 releases now).

I think I got the autoconf bits right as I had to rewrite that over what is
in the tree for autoconf as it is just some hacked up code for the generated
autoconf script at the moment.

–
This message has been scanned for viruses and
dangerous content by MailScanner, and is
believed to be clean.

icculus · July 8, 2012, 11:21am

Still looking for any feedback. I’d like to get this in.

This looks reasonable to me.

This is now hg changeset dfcbd0d9209c, thanks!

–ryan.