oss.c - qemu - Git at Google

 /*
  * QEMU OSS Audio output driver
  *
  * Copyright (c) 2003 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 "vl.h"

 #ifndef _WIN32
 #include <fcntl.h>
 #include <errno.h>
 #include <stdio.h>
 #include <unistd.h>
 #include <string.h>
 #include <stdlib.h>
 #include <limits.h>
 #include <inttypes.h>
 #include <sys/types.h>
 #include <sys/ioctl.h>
 #include <sys/soundcard.h>


 /* http://www.df.lth.se/~john_e/gems/gem002d.html */
 /* http://www.multi-platforms.com/Tips/PopCount.htm */
 static inline uint32_t popcount (uint32_t u)
 {
   u = ((u&0x55555555) + ((u>>1)&0x55555555));
   u = ((u&0x33333333) + ((u>>2)&0x33333333));
   u = ((u&0x0f0f0f0f) + ((u>>4)&0x0f0f0f0f));
   u = ((u&0x00ff00ff) + ((u>>8)&0x00ff00ff));
   u = ( u&0x0000ffff) + (u>>16);
   return u;
 }

 static inline uint32_t lsbindex (uint32_t u)
 {
   return popcount ((u&-u)-1);
 }

 #define MIN(a, b) ((a)>(b)?(b):(a))
 #define MAX(a, b) ((a)<(b)?(b):(a))

 #define DEREF(x) (void)x
 #define log(...) fprintf (stderr, "oss: " __VA_ARGS__)
 #define ERRFail(...) do {                                       \
     int _errno = errno;                                         \
     fprintf (stderr, "oss: " __VA_ARGS__);                      \
     fprintf (stderr, "system error: %s\n", strerror (_errno));  \
     abort ();                                                   \
 } while (0)
 #define Fail(...) do {                          \
     fprintf (stderr, "oss: " __VA_ARGS__);      \
     fprintf (stderr, "\n");                     \
     abort ();                                   \
 } while (0)

 #ifdef DEBUG_OSS
 #define lwarn(...) fprintf (stderr, "oss: " __VA_ARGS__)
 #define linfo(...) fprintf (stderr, "oss: " __VA_ARGS__)
 #define ldebug(...) fprintf (stderr, "oss: " __VA_ARGS__)
 #else
 #define lwarn(...)
 #define linfo(...)
 #define ldebug(...)
 #endif


 #define IOCTL(args) do {                        \
   int ret = ioctl args;                         \
   if (-1 == ret) {                              \
     ERRFail (#args);                            \
   }                                             \
   ldebug ("ioctl " #args " = %d\n", ret);       \
 } while (0)

 static int audio_fd = -1;
 static int freq;
 static int conf_nfrags = 4;
 static int conf_fragsize;
 static int nfrags;
 static int fragsize;
 static int bufsize;
 static int nchannels;
 static int fmt;
 static int rpos;
 static int wpos;
 static int atom;
 static int live;
 static int leftover;
 static int bytes_per_second;
 static void *buf;
 static enum {DONT, DSP, TID} estimate = TID;

 static void (*copy_fn)(void *, void *, int);

 static void copy_no_conversion (void *dst, void *src, int size)
 {
     memcpy (dst, src, size);
 }

 static void copy_u16_to_s16 (void *dst, void *src, int size)
 {
     int i;
     uint16_t *out, *in;

     out = dst;
     in = src;

     for (i = 0; i < size / 2; i++) {
         out[i] = in[i] + 0x8000;
     }
 }

 static void pab (struct audio_buf_info *abinfo)
 {
     DEREF (abinfo);

     ldebug ("fragments %d, fragstotal %d, fragsize %d, bytes %d\n"
             "rpos %d, wpos %d, live %d\n",
             abinfo->fragments,
             abinfo->fragstotal,
             abinfo->fragsize,
             abinfo->bytes,
             rpos, wpos, live);
 }

 void AUD_reset (int rfreq, int rnchannels, audfmt_e rfmt)
 {
     int fmt_;
     int bits16;

     if (-1 == audio_fd) {
         AUD_open (rfreq, rnchannels, rfmt);
         return;
     }

     switch (rfmt) {
     case AUD_FMT_U8:
         bits16 = 0;
         fmt_ = AFMT_U8;
         copy_fn = copy_no_conversion;
         atom = 1;
         break;

     case AUD_FMT_S8:
         Fail ("can not play 8bit signed");

     case AUD_FMT_S16:
         bits16 = 1;
         fmt_ = AFMT_S16_LE;
         copy_fn = copy_no_conversion;
         atom = 2;
         break;

     case AUD_FMT_U16:
         bits16 = 1;
         fmt_ = AFMT_S16_LE;
         copy_fn = copy_u16_to_s16;
         atom = 2;
         break;

     default:
         abort ();
     }

     if ((fmt_ == fmt) && (bits16 + 1 == nchannels) && (rfreq == freq))
         return;
     else {
         AUD_open (rfreq, rnchannels, rfmt);
     }
 }

 void AUD_open (int rfreq, int rnchannels, audfmt_e rfmt)
 {
     int fmt_;
     int mmmmssss;
     struct audio_buf_info abinfo;
     int _fmt;
     int _freq;
     int _nchannels;
     int bits16;

     bits16 = 0;

     switch (rfmt) {
     case AUD_FMT_U8:
         bits16 = 0;
         fmt_ = AFMT_U8;
         copy_fn = copy_no_conversion;
         atom = 1;
         break;

     case AUD_FMT_S8:
         Fail ("can not play 8bit signed");

     case AUD_FMT_S16:
         bits16 = 1;
         fmt_ = AFMT_S16_LE;
         copy_fn = copy_no_conversion;
         atom = 2;
         break;

     case AUD_FMT_U16:
         bits16 = 1;
         fmt_ = AFMT_S16_LE;
         copy_fn = copy_u16_to_s16;
         atom = 2;
         break;

     default:
         abort ();
     }

     if (buf) {
         free (buf);
         buf = 0;
     }

     if (-1 != audio_fd)
         close (audio_fd);

     audio_fd = open ("/dev/dsp", O_WRONLY | O_NONBLOCK);
     if (-1 == audio_fd) {
         ERRFail ("can not open /dev/dsp");
     }

     _fmt = fmt_;
     _freq = rfreq;
     _nchannels = rnchannels;

     IOCTL ((audio_fd, SNDCTL_DSP_RESET, 1));
     IOCTL ((audio_fd, SNDCTL_DSP_SAMPLESIZE, &_fmt));
     IOCTL ((audio_fd, SNDCTL_DSP_CHANNELS, &_nchannels));
     IOCTL ((audio_fd, SNDCTL_DSP_SPEED, &_freq));
     IOCTL ((audio_fd, SNDCTL_DSP_NONBLOCK));

     /* from oss.pdf:

     The argument to this call is an integer encoded as 0xMMMMSSSS (in
     hex). The 16 least significant bits determine the fragment
     size. The size is 2^SSSS. For examp le SSSS=0008 gives fragment
     size of 256 bytes (2^8). The minimum is 16 bytes (SSSS=4) and the
     maximum is total_buffer_size/2. Some devices or processor
     architectures may require larger fragments - in this case the
     requested fragment size is automatically increased.

     So ahem... 4096 = 2^12, and grand total 0x0004000c
     */

     mmmmssss = (conf_nfrags << 16) | conf_fragsize;
     IOCTL ((audio_fd, SNDCTL_DSP_SETFRAGMENT, &mmmmssss));

     linfo ("_fmt = %d, fmt = %d\n"
            "_channels = %d, rnchannels = %d\n"
            "_freq = %d, freq = %d\n",
            _fmt, fmt_,
            _nchannels, rnchannels,
            _freq, rfreq);

     if (_fmt != fmt_) {
         Fail ("format %d != %d", _fmt, fmt_);
     }

     if (_nchannels != rnchannels) {
         Fail ("channels %d != %d", _nchannels, rnchannels);
     }

     if (_freq != rfreq) {
         Fail ("freq %d != %d", _freq, rfreq);
     }

     IOCTL ((audio_fd, SNDCTL_DSP_GETOSPACE, &abinfo));

     nfrags = abinfo.fragstotal;
     fragsize = abinfo.fragsize;
     freq = _freq;
     fmt = _fmt;
     nchannels = rnchannels;
     atom <<= nchannels >>  1;
     bufsize = nfrags * fragsize;

     bytes_per_second = (freq << (nchannels >> 1)) << bits16;

     linfo ("bytes per second %d\n", bytes_per_second);

     linfo ("fragments %d, fragstotal %d, fragsize %d, bytes %d, bufsize %d\n",
            abinfo.fragments,
            abinfo.fragstotal,
            abinfo.fragsize,
            abinfo.bytes,
            bufsize);

     if (NULL == buf) {
         buf = malloc (bufsize);
         if (NULL == buf) {
             abort ();
         }
     }

     rpos = 0;
     wpos = 0;
     live = 0;
 }

 int AUD_write (void *in_buf, int size)
 {
     int to_copy, temp;
     uint8_t *in, *out;

     to_copy = MIN (bufsize - live, size);

     temp = to_copy;

     in = in_buf;
     out = buf;

     while (temp) {
         int copy;

         copy = MIN (temp, bufsize - wpos);
         copy_fn (out + wpos, in, copy);

         wpos += copy;
         if (wpos == bufsize) {
             wpos = 0;
         }

         temp -= copy;
         in += copy;
         live += copy;
     }

     return to_copy;
 }

 void AUD_run (void)
 {
     int res;
     int bytes;
     struct audio_buf_info abinfo;

     if (0 == live)
         return;

     res = ioctl (audio_fd, SNDCTL_DSP_GETOSPACE, &abinfo);

     if (-1 == res) {
         int err;

         err = errno;
         lwarn ("SNDCTL_DSP_GETOSPACE failed with %s\n", strerror (err));
     }

     bytes = abinfo.bytes;
     bytes = MIN (live, bytes);
 #if 0
     bytes = (bytes / fragsize) * fragsize;
 #endif

     while (bytes) {
         int left, play, written;

         left = bufsize - rpos;
         play = MIN (left, bytes);
         written = write (audio_fd, (void *) ((uint32_t) buf + rpos), play);

         if (-1 == written) {
             if (EAGAIN == errno || EINTR == errno) {
                 return;
             }
             else {
                 ERRFail ("write audio");
             }
         }

         play = written;
         live -= play;
         rpos += play;
         bytes -= play;

         if (rpos == bufsize) {
             rpos = 0;
         }
     }
 }

 static int get_dsp_bytes (void)
 {
     int res;
     struct count_info info;

     res = ioctl (audio_fd, SNDCTL_DSP_GETOPTR, &info);
     if (-1 == res) {
         int err;

         err = errno;
         lwarn ("SNDCTL_DSP_GETOPTR failed with %s\n", strerror (err));
         return -1;
     }
     else {
         ldebug ("bytes %d\n", info.bytes);
         return info.bytes;
     }
 }

 void AUD_adjust_estimate (int _leftover)
 {
     leftover = _leftover;
 }

 int AUD_get_free (void)
 {
     int free, elapsed;

     free = bufsize - live;

     if (0 == free)
         return 0;

     elapsed = free;
     switch (estimate) {
     case DONT:
         break;

     case DSP:
         {
             static int old_bytes;
             int bytes;

             bytes = get_dsp_bytes ();
             if (bytes <= 0)
                 return free;

             elapsed = bytes - old_bytes;
             old_bytes = bytes;
             ldebug ("dsp elapsed %d bytes\n", elapsed);
             break;
         }

     case TID:
         {
             static uint64_t old_ticks;
             uint64_t ticks, delta;
             uint64_t ua_elapsed;
             uint64_t al_elapsed;

             ticks = qemu_get_clock(rt_clock);
             delta = ticks - old_ticks;
             old_ticks = ticks;

             ua_elapsed = (delta * bytes_per_second) / 1000;
             al_elapsed = ua_elapsed & ~3ULL;

             ldebug ("tid elapsed %llu bytes\n", ua_elapsed);

             if (al_elapsed > (uint64_t) INT_MAX)
                 elapsed = INT_MAX;
             else
                 elapsed = al_elapsed;

             elapsed += leftover;
         }
     }

     if (elapsed > free) {
         lwarn ("audio can not keep up elapsed %d free %d\n", elapsed, free);
         return free;
     }
     else {
         return elapsed;
     }
 }

 int AUD_get_live (void)
 {
     return live;
 }

 int AUD_get_buffer_size (void)
 {
     return bufsize;
 }

 void AUD_init (void)
 {
     int fsp;
     int _fragsize = 4096;

     DEREF (pab);

     fsp = _fragsize;
     if (0 != (fsp & (fsp - 1))) {
         Fail ("fragment size %d is not power of 2", fsp);
     }

     conf_fragsize = lsbindex (fsp);
 }

 #else

 void AUD_run (void)
 {
 }

 int AUD_write (void *in_buf, int size)
 {
     return 0;
 }

 void AUD_reset (int rfreq, int rnchannels, audfmt_e rfmt)
 {
 }

 void AUD_adjust_estimate (int _leftover)
 {
 }

 int AUD_get_free (void)
 {
     return 0;
 }

 int AUD_get_live (void)
 {
     return 0;
 }

 int AUD_get_buffer_size (void)
 {
     return 0;
 }

 void AUD_init (void)
 {
 }

 #endif
	/*
	* QEMU OSS Audio output driver
	*
	* Copyright (c) 2003 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 "vl.h"

	#ifndef _WIN32
	#include <fcntl.h>
	#include <errno.h>
	#include <stdio.h>
	#include <unistd.h>
	#include <string.h>
	#include <stdlib.h>
	#include <limits.h>
	#include <inttypes.h>
	#include <sys/types.h>
	#include <sys/ioctl.h>
	#include <sys/soundcard.h>


	/* http://www.df.lth.se/~john_e/gems/gem002d.html */
	/* http://www.multi-platforms.com/Tips/PopCount.htm */
	static inline uint32_t popcount (uint32_t u)
	{
	u = ((u&0x55555555) + ((u>>1)&0x55555555));
	u = ((u&0x33333333) + ((u>>2)&0x33333333));
	u = ((u&0x0f0f0f0f) + ((u>>4)&0x0f0f0f0f));
	u = ((u&0x00ff00ff) + ((u>>8)&0x00ff00ff));
	u = ( u&0x0000ffff) + (u>>16);
	return u;
	}

	static inline uint32_t lsbindex (uint32_t u)
	{
	return popcount ((u&-u)-1);
	}

	#define MIN(a, b) ((a)>(b)?(b):(a))
	#define MAX(a, b) ((a)<(b)?(b):(a))

	#define DEREF(x) (void)x
	#define log(...) fprintf (stderr, "oss: " __VA_ARGS__)
	#define ERRFail(...) do { \
	int _errno = errno; \
	fprintf (stderr, "oss: " __VA_ARGS__); \
	fprintf (stderr, "system error: %s\n", strerror (_errno)); \
	abort (); \
	} while (0)
	#define Fail(...) do { \
	fprintf (stderr, "oss: " __VA_ARGS__); \
	fprintf (stderr, "\n"); \
	abort (); \
	} while (0)

	#ifdef DEBUG_OSS
	#define lwarn(...) fprintf (stderr, "oss: " __VA_ARGS__)
	#define linfo(...) fprintf (stderr, "oss: " __VA_ARGS__)
	#define ldebug(...) fprintf (stderr, "oss: " __VA_ARGS__)
	#else
	#define lwarn(...)
	#define linfo(...)
	#define ldebug(...)
	#endif


	#define IOCTL(args) do { \
	int ret = ioctl args; \
	if (-1 == ret) { \
	ERRFail (#args); \
	} \
	ldebug ("ioctl " #args " = %d\n", ret); \
	} while (0)

	static int audio_fd = -1;
	static int freq;
	static int conf_nfrags = 4;
	static int conf_fragsize;
	static int nfrags;
	static int fragsize;
	static int bufsize;
	static int nchannels;
	static int fmt;
	static int rpos;
	static int wpos;
	static int atom;
	static int live;
	static int leftover;
	static int bytes_per_second;
	static void *buf;
	static enum {DONT, DSP, TID} estimate = TID;

	static void (copy_fn)(void , void *, int);

	static void copy_no_conversion (void dst, void src, int size)
	{
	memcpy (dst, src, size);
	}

	static void copy_u16_to_s16 (void dst, void src, int size)
	{
	int i;
	uint16_t out, in;

	out = dst;
	in = src;

	for (i = 0; i < size / 2; i++) {
	out[i] = in[i] + 0x8000;
	}
	}

	static void pab (struct audio_buf_info *abinfo)
	{
	DEREF (abinfo);

	ldebug ("fragments %d, fragstotal %d, fragsize %d, bytes %d\n"
	"rpos %d, wpos %d, live %d\n",
	abinfo->fragments,
	abinfo->fragstotal,
	abinfo->fragsize,
	abinfo->bytes,
	rpos, wpos, live);
	}

	void AUD_reset (int rfreq, int rnchannels, audfmt_e rfmt)
	{
	int fmt_;
	int bits16;

	if (-1 == audio_fd) {
	AUD_open (rfreq, rnchannels, rfmt);
	return;
	}

	switch (rfmt) {
	case AUD_FMT_U8:
	bits16 = 0;
	fmt_ = AFMT_U8;
	copy_fn = copy_no_conversion;
	atom = 1;
	break;

	case AUD_FMT_S8:
	Fail ("can not play 8bit signed");

	case AUD_FMT_S16:
	bits16 = 1;
	fmt_ = AFMT_S16_LE;
	copy_fn = copy_no_conversion;
	atom = 2;
	break;

	case AUD_FMT_U16:
	bits16 = 1;
	fmt_ = AFMT_S16_LE;
	copy_fn = copy_u16_to_s16;
	atom = 2;
	break;

	default:
	abort ();
	}

	if ((fmt_ == fmt) && (bits16 + 1 == nchannels) && (rfreq == freq))
	return;
	else {
	AUD_open (rfreq, rnchannels, rfmt);
	}
	}

	void AUD_open (int rfreq, int rnchannels, audfmt_e rfmt)
	{
	int fmt_;
	int mmmmssss;
	struct audio_buf_info abinfo;
	int _fmt;
	int _freq;
	int _nchannels;
	int bits16;

	bits16 = 0;

	switch (rfmt) {
	case AUD_FMT_U8:
	bits16 = 0;
	fmt_ = AFMT_U8;
	copy_fn = copy_no_conversion;
	atom = 1;
	break;

	case AUD_FMT_S8:
	Fail ("can not play 8bit signed");

	case AUD_FMT_S16:
	bits16 = 1;
	fmt_ = AFMT_S16_LE;
	copy_fn = copy_no_conversion;
	atom = 2;
	break;

	case AUD_FMT_U16:
	bits16 = 1;
	fmt_ = AFMT_S16_LE;
	copy_fn = copy_u16_to_s16;
	atom = 2;
	break;

	default:
	abort ();
	}

	if (buf) {
	free (buf);
	buf = 0;
	}

	if (-1 != audio_fd)
	close (audio_fd);

	audio_fd = open ("/dev/dsp", O_WRONLY \| O_NONBLOCK);
	if (-1 == audio_fd) {
	ERRFail ("can not open /dev/dsp");
	}

	_fmt = fmt_;
	_freq = rfreq;
	_nchannels = rnchannels;

	IOCTL ((audio_fd, SNDCTL_DSP_RESET, 1));
	IOCTL ((audio_fd, SNDCTL_DSP_SAMPLESIZE, &_fmt));
	IOCTL ((audio_fd, SNDCTL_DSP_CHANNELS, &_nchannels));
	IOCTL ((audio_fd, SNDCTL_DSP_SPEED, &_freq));
	IOCTL ((audio_fd, SNDCTL_DSP_NONBLOCK));

	/* from oss.pdf:

	The argument to this call is an integer encoded as 0xMMMMSSSS (in
	hex). The 16 least significant bits determine the fragment
	size. The size is 2^SSSS. For examp le SSSS=0008 gives fragment
	size of 256 bytes (2^8). The minimum is 16 bytes (SSSS=4) and the
	maximum is total_buffer_size/2. Some devices or processor
	architectures may require larger fragments - in this case the
	requested fragment size is automatically increased.

	So ahem... 4096 = 2^12, and grand total 0x0004000c
	*/

	mmmmssss = (conf_nfrags << 16) \| conf_fragsize;
	IOCTL ((audio_fd, SNDCTL_DSP_SETFRAGMENT, &mmmmssss));

	linfo ("_fmt = %d, fmt = %d\n"
	"_channels = %d, rnchannels = %d\n"
	"_freq = %d, freq = %d\n",
	_fmt, fmt_,
	_nchannels, rnchannels,
	_freq, rfreq);

	if (_fmt != fmt_) {
	Fail ("format %d != %d", _fmt, fmt_);
	}

	if (_nchannels != rnchannels) {
	Fail ("channels %d != %d", _nchannels, rnchannels);
	}

	if (_freq != rfreq) {
	Fail ("freq %d != %d", _freq, rfreq);
	}

	IOCTL ((audio_fd, SNDCTL_DSP_GETOSPACE, &abinfo));

	nfrags = abinfo.fragstotal;
	fragsize = abinfo.fragsize;
	freq = _freq;
	fmt = _fmt;
	nchannels = rnchannels;
	atom <<= nchannels >> 1;
	bufsize = nfrags * fragsize;

	bytes_per_second = (freq << (nchannels >> 1)) << bits16;

	linfo ("bytes per second %d\n", bytes_per_second);

	linfo ("fragments %d, fragstotal %d, fragsize %d, bytes %d, bufsize %d\n",
	abinfo.fragments,
	abinfo.fragstotal,
	abinfo.fragsize,
	abinfo.bytes,
	bufsize);

	if (NULL == buf) {
	buf = malloc (bufsize);
	if (NULL == buf) {
	abort ();
	}
	}

	rpos = 0;
	wpos = 0;
	live = 0;
	}

	int AUD_write (void *in_buf, int size)
	{
	int to_copy, temp;
	uint8_t in, out;

	to_copy = MIN (bufsize - live, size);

	temp = to_copy;

	in = in_buf;
	out = buf;

	while (temp) {
	int copy;

	copy = MIN (temp, bufsize - wpos);
	copy_fn (out + wpos, in, copy);

	wpos += copy;
	if (wpos == bufsize) {
	wpos = 0;
	}

	temp -= copy;
	in += copy;
	live += copy;
	}

	return to_copy;
	}

	void AUD_run (void)
	{
	int res;
	int bytes;
	struct audio_buf_info abinfo;

	if (0 == live)
	return;

	res = ioctl (audio_fd, SNDCTL_DSP_GETOSPACE, &abinfo);

	if (-1 == res) {
	int err;

	err = errno;
	lwarn ("SNDCTL_DSP_GETOSPACE failed with %s\n", strerror (err));
	}

	bytes = abinfo.bytes;
	bytes = MIN (live, bytes);
	#if 0
	bytes = (bytes / fragsize) * fragsize;
	#endif

	while (bytes) {
	int left, play, written;

	left = bufsize - rpos;
	play = MIN (left, bytes);
	written = write (audio_fd, (void *) ((uint32_t) buf + rpos), play);

	if (-1 == written) {
	if (EAGAIN == errno \|\| EINTR == errno) {
	return;
	}
	else {
	ERRFail ("write audio");
	}
	}

	play = written;
	live -= play;
	rpos += play;
	bytes -= play;

	if (rpos == bufsize) {
	rpos = 0;
	}
	}
	}

	static int get_dsp_bytes (void)
	{
	int res;
	struct count_info info;

	res = ioctl (audio_fd, SNDCTL_DSP_GETOPTR, &info);
	if (-1 == res) {
	int err;

	err = errno;
	lwarn ("SNDCTL_DSP_GETOPTR failed with %s\n", strerror (err));
	return -1;
	}
	else {
	ldebug ("bytes %d\n", info.bytes);
	return info.bytes;
	}
	}

	void AUD_adjust_estimate (int _leftover)
	{
	leftover = _leftover;
	}

	int AUD_get_free (void)
	{
	int free, elapsed;

	free = bufsize - live;

	if (0 == free)
	return 0;

	elapsed = free;
	switch (estimate) {
	case DONT:
	break;

	case DSP:
	{
	static int old_bytes;
	int bytes;

	bytes = get_dsp_bytes ();
	if (bytes <= 0)
	return free;

	elapsed = bytes - old_bytes;
	old_bytes = bytes;
	ldebug ("dsp elapsed %d bytes\n", elapsed);
	break;
	}

	case TID:
	{
	static uint64_t old_ticks;
	uint64_t ticks, delta;
	uint64_t ua_elapsed;
	uint64_t al_elapsed;

	ticks = qemu_get_clock(rt_clock);
	delta = ticks - old_ticks;
	old_ticks = ticks;

	ua_elapsed = (delta * bytes_per_second) / 1000;
	al_elapsed = ua_elapsed & ~3ULL;

	ldebug ("tid elapsed %llu bytes\n", ua_elapsed);

	if (al_elapsed > (uint64_t) INT_MAX)
	elapsed = INT_MAX;
	else
	elapsed = al_elapsed;

	elapsed += leftover;
	}
	}

	if (elapsed > free) {
	lwarn ("audio can not keep up elapsed %d free %d\n", elapsed, free);
	return free;
	}
	else {
	return elapsed;
	}
	}

	int AUD_get_live (void)
	{
	return live;
	}

	int AUD_get_buffer_size (void)
	{
	return bufsize;
	}

	void AUD_init (void)
	{
	int fsp;
	int _fragsize = 4096;

	DEREF (pab);

	fsp = _fragsize;
	if (0 != (fsp & (fsp - 1))) {
	Fail ("fragment size %d is not power of 2", fsp);
	}

	conf_fragsize = lsbindex (fsp);
	}

	#else

	void AUD_run (void)
	{
	}

	int AUD_write (void *in_buf, int size)
	{
	return 0;
	}

	void AUD_reset (int rfreq, int rnchannels, audfmt_e rfmt)
	{
	}

	void AUD_adjust_estimate (int _leftover)
	{
	}

	int AUD_get_free (void)
	{
	return 0;
	}

	int AUD_get_live (void)
	{
	return 0;
	}

	int AUD_get_buffer_size (void)
	{
	return 0;
	}

	void AUD_init (void)
	{
	}

	#endif