ALSA backend (based on Dummy backend and zita-alsa-pcmi)

1 files changed, 1127 insertions, 0 deletions

diff --git a/libs/backends/alsa/zita-alsa-pcmi.cc b/libs/backends/alsa/zita-alsa-pcmi.cc
new file mode 100644
index 0000000000..8947e1a12e
--- /dev/null
+++ b/libs/backends/alsa/zita-alsa-pcmi.cc
@@ -0,0 +1,1127 @@
+// ----------------------------------------------------------------------------
+//
+//  Copyright (C) 2006-2012 Fons Adriaensen <fons@linuxaudio.org>
+//
+//  This program is free software; you can redistribute it and/or modify
+//  it under the terms of the GNU General Public License as published by
+//  the Free Software Foundation; either version 3 of the License, or
+//  (at your option) any later version.
+//
+//  This program is distributed in the hope that it will be useful,
+//  but WITHOUT ANY WARRANTY; without even the implied warranty of
+//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//  GNU General Public License for more details.
+//
+//  You should have received a copy of the GNU General Public License
+//  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+// ----------------------------------------------------------------------------
+
+
+#include <endian.h>
+#include <sys/time.h>
+#include "zita-alsa-pcmi.h"
+
+
+// Public members ----------------------------------------------------------------------
+
+
+int zita_alsa_pcmi_major_version (void)
+{
+	return ZITA_ALSA_PCMI_MAJOR_VERSION;
+}
+
+
+int zita_alsa_pcmi_minor_version (void)
+{
+	return ZITA_ALSA_PCMI_MINOR_VERSION;
+}
+
+
+Alsa_pcmi::Alsa_pcmi (
+		const char        *play_name,
+		const char        *capt_name,
+		const char        *ctrl_name,
+		unsigned int       fsamp,
+		unsigned int       fsize,
+		unsigned int       nfrag,
+		unsigned int       debug)
+	: _fsamp (fsamp)
+	, _fsize (fsize)
+	, _nfrag (nfrag)
+	, _debug (debug)
+	, _state (-1)
+	, _play_handle (0)
+	, _capt_handle (0)
+	, _ctrl_handle (0)
+	, _play_hwpar (0)
+	, _play_swpar (0)
+	, _capt_hwpar (0)
+	, _capt_swpar (0)
+	, _play_nchan (0)
+	, _capt_nchan (0)
+	, _play_xrun (0)
+	, _capt_xrun (0)
+	, _synced (false)
+	, _play_npfd (0)
+	, _capt_npfd (0)
+{
+	const char *p;
+
+	p = getenv ("ZITA_ALSA_PCMI_DEBUG");
+	if (p && *p) _debug = atoi (p);
+	initialise (play_name, capt_name, ctrl_name);
+}
+
+
+Alsa_pcmi::~Alsa_pcmi (void)
+{
+	if (_play_handle) snd_pcm_close (_play_handle);
+	if (_capt_handle) snd_pcm_close (_capt_handle);
+	if (_ctrl_handle) snd_ctl_close (_ctrl_handle);
+
+	snd_pcm_sw_params_free (_capt_swpar);
+	snd_pcm_hw_params_free (_capt_hwpar);
+	snd_pcm_sw_params_free (_play_swpar);
+	snd_pcm_hw_params_free (_play_hwpar);
+}
+
+
+int Alsa_pcmi::pcm_start (void)
+{
+	unsigned int i, j, n;
+	int          err;
+
+	if (_play_handle)
+	{
+		n = snd_pcm_avail_update (_play_handle);
+		if (n != _fsize * _nfrag)
+		{
+			if (_debug & DEBUG_STAT) fprintf  (stderr, "Alsa_pcmi: full buffer not available at start.\n");
+			return -1;
+		}
+		for (i = 0; i < _nfrag; i++)
+		{
+			play_init (_fsize);
+			for (j = 0; j < _play_nchan; j++) clear_chan (j, _fsize);
+			play_done (_fsize);
+		}
+		if ((err = snd_pcm_start (_play_handle)) < 0)
+		{
+			if (_debug & DEBUG_STAT) fprintf (stderr, "Alsa_pcmi: pcm_start(play): %s.\n", snd_strerror (err));
+			return -1;
+		}
+	}
+	if (_capt_handle && !_synced && ((err = snd_pcm_start (_capt_handle)) < 0))
+	{
+		if (_debug & DEBUG_STAT) fprintf (stderr, "Alsa_pcmi: pcm_start(capt): %s.\n", snd_strerror (err));
+		return -1;
+	}
+
+	return 0;
+}
+
+
+int Alsa_pcmi::pcm_stop (void)
+{
+	int err;
+
+	if (_play_handle && ((err = snd_pcm_drop (_play_handle)) < 0))
+	{
+		if (_debug & DEBUG_STAT) fprintf (stderr, "Alsa_pcmi: pcm_drop(play): %s.\n", snd_strerror (err));
+		return -1;
+	}
+	if (_capt_handle && !_synced && ((err = snd_pcm_drop (_capt_handle)) < 0))
+	{
+		if (_debug & DEBUG_STAT) fprintf (stderr, "Alsa_pcmi: pcm_drop(capt): %s.\n", snd_strerror (err));
+		return -1;
+	}
+
+	return 0;
+}
+
+
+snd_pcm_sframes_t Alsa_pcmi::pcm_wait (void)
+{
+	bool              need_capt;
+	bool              need_play;
+	snd_pcm_sframes_t capt_av;
+	snd_pcm_sframes_t play_av;
+	unsigned short    rev;
+	int               i, r, n1, n2;
+
+	_state = 0;
+	need_capt = _capt_handle ? true : false;
+	need_play = _play_handle ? true : false;
+
+	while (need_play || need_capt)
+	{
+		n1 = 0;
+		if (need_play)
+		{
+			snd_pcm_poll_descriptors (_play_handle, _poll_fd, _play_npfd);
+			n1 += _play_npfd;
+		}
+		n2 = n1;
+		if (need_capt)
+		{
+			snd_pcm_poll_descriptors (_capt_handle, _poll_fd + n1, _capt_npfd);
+			n2 += _capt_npfd;
+		}
+		for (i = 0; i < n2; i++) _poll_fd [i].events |= POLLERR;
+
+		r = poll (_poll_fd, n2, 1000);
+		if (r < 0)
+		{
+			if (errno == EINTR) return 0;
+			if (_debug & DEBUG_WAIT) fprintf (stderr, "Alsa_pcmi: poll(): %s\n.", strerror (errno));
+			_state = -1;
+			return 0;
+		}
+		if (r == 0)
+		{
+			if (_debug & DEBUG_WAIT) fprintf (stderr, "Alsa_pcmi: poll timed out.\n");
+			_state = -1;
+			return 0;
+		}
+
+		if (need_play)
+		{
+			snd_pcm_poll_descriptors_revents (_play_handle, _poll_fd, n1, &rev);
+			if (rev & POLLERR)
+			{
+				if (_debug & DEBUG_WAIT) fprintf (stderr, "Alsa_pcmi: error on playback pollfd.\n");
+				_state = 1;
+				recover ();
+				return 0;
+			}
+			if (rev & POLLOUT) need_play = false;
+		}
+		if (need_capt)
+		{
+			snd_pcm_poll_descriptors_revents (_capt_handle, _poll_fd + n1, n2 - n1, &rev);
+			if (rev & POLLERR)
+			{
+				if (_debug & DEBUG_WAIT) fprintf (stderr, "Alsa_pcmi: error on capture pollfd.\n");
+				_state = 1;
+				recover ();
+				return 0;
+			}
+			if (rev & POLLIN) need_capt = false;
+		}
+	}
+
+	play_av = 999999999;
+	if (_play_handle && (play_av = snd_pcm_avail_update (_play_handle)) < 0)
+	{
+		_state = -1;
+		recover ();
+		return 0;
+	}
+	capt_av = 999999999;
+	if (_capt_handle && (capt_av = snd_pcm_avail_update (_capt_handle)) < 0)
+	{
+		_state = -1;
+		recover ();
+		return 0;
+	}
+
+	return (capt_av < play_av) ? capt_av : play_av;
+}
+
+
+int Alsa_pcmi::pcm_idle (int len)
+{
+	unsigned int       i;
+	snd_pcm_uframes_t  n, k;
+
+	if (_capt_handle)
+	{
+		n = len;
+		while (n)
+		{
+			k = capt_init (n);
+			capt_done (k);
+			n -= k;
+		}
+	}
+	if (_play_handle)
+	{
+		n = len;
+		while (n)
+		{
+			k = play_init (n);
+			for (i = 0; i < _play_nchan; i++) clear_chan (i, k);
+			play_done (k);
+			n -= k;
+		}
+	}
+	return 0;
+}
+
+
+int Alsa_pcmi::play_init (snd_pcm_uframes_t len)
+{
+	unsigned int                   i;
+	const snd_pcm_channel_area_t   *a;
+	int                            err;
+
+	if ((err = snd_pcm_mmap_begin (_play_handle, &a, &_play_offs, &len)) < 0)
+	{
+		if (_debug & DEBUG_DATA) fprintf (stderr, "Alsa_pcmi: snd_pcm_mmap_begin(play): %s.\n", snd_strerror (err));
+		return -1;
+	}
+	_play_step = (a->step) >> 3;
+	for (i = 0; i < _play_nchan; i++, a++)
+	{
+		_play_ptr [i] = (char *) a->addr + ((a->first + a->step * _play_offs) >> 3);
+	}
+
+	return len;
+}
+
+
+int Alsa_pcmi::capt_init (snd_pcm_uframes_t len)
+{
+	unsigned int                  i;
+	const snd_pcm_channel_area_t  *a;
+	int                           err;
+
+	if ((err = snd_pcm_mmap_begin (_capt_handle, &a, &_capt_offs, &len)) < 0)
+	{
+		if (_debug & DEBUG_DATA) fprintf (stderr, "Alsa_pcmi: snd_pcm_mmap_begin(capt): %s.\n", snd_strerror (err));
+		return -1;
+	}
+	_capt_step = (a->step) >> 3;
+	for (i = 0; i < _capt_nchan; i++, a++)
+	{
+		_capt_ptr [i] = (char *) a->addr + ((a->first + a->step * _capt_offs) >> 3);
+	}
+
+	return len;
+}
+
+
+void Alsa_pcmi::clear_chan (int chan, int len)
+{
+	_play_ptr [chan] = (this->*Alsa_pcmi::_clear_func)(_play_ptr [chan], len);
+}
+
+
+void Alsa_pcmi::play_chan (int chan, const float *src, int len, int step)
+{
+	_play_ptr [chan] = (this->*Alsa_pcmi::_play_func)(src, _play_ptr [chan], len, step);
+}
+
+
+void Alsa_pcmi::capt_chan  (int chan, float *dst, int len, int step)
+{
+	_capt_ptr [chan] = (this->*Alsa_pcmi::_capt_func)(_capt_ptr [chan], dst, len, step);
+}
+
+
+int Alsa_pcmi::play_done (int len)
+{
+	return snd_pcm_mmap_commit (_play_handle, _play_offs, len);
+}
+
+
+int Alsa_pcmi::capt_done (int len)
+{
+	return snd_pcm_mmap_commit (_capt_handle, _capt_offs, len);
+}
+
+
+void Alsa_pcmi::printinfo (void)
+{
+	fprintf (stdout, "playback :");
+	if (_play_handle)
+	{
+		fprintf (stdout, "\n  nchan  : %d\n", _play_nchan);
+		fprintf (stdout, "  fsamp  : %d\n", _fsamp);
+		fprintf (stdout, "  fsize  : %ld\n", _fsize);
+		fprintf (stdout, "  nfrag  : %d\n", _nfrag);
+		fprintf (stdout, "  format : %s\n", snd_pcm_format_name (_play_format));
+	}
+	else fprintf (stdout, " not enabled\n");
+	fprintf (stdout, "capture  :");
+	if (_capt_handle)
+	{
+		fprintf (stdout, "\n  nchan  : %d\n", _capt_nchan);
+		fprintf (stdout, "  fsamp  : %d\n", _fsamp);
+		fprintf (stdout, "  fsize  : %ld\n", _fsize);
+		fprintf (stdout, "  nfrag  : %d\n", _nfrag);
+		fprintf (stdout, "  format : %s\n", snd_pcm_format_name (_capt_format));
+		if (_play_handle) fprintf (stdout, "%s\n", _synced ? "synced" : "not synced");
+	}
+	else fprintf (stdout, " not enabled\n");
+}
+
+
+// Private members ---------------------------------------------------------------------
+
+
+void Alsa_pcmi::initialise (const char *play_name, const char *capt_name, const char *ctrl_name)
+{
+	unsigned int          fsamp;
+	snd_pcm_uframes_t     fsize;
+	unsigned int          nfrag;
+	int                   err;
+	int                   dir;
+	snd_ctl_card_info_t  *card;
+
+	if (play_name)
+	{
+		if (snd_pcm_open (&_play_handle, play_name, SND_PCM_STREAM_PLAYBACK, 0) < 0)
+		{
+			_play_handle = 0;
+			if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: Cannot open PCM device %s for playback.\n",
+					play_name);
+		}
+	}
+
+	if (capt_name)
+	{
+		if (snd_pcm_open (&_capt_handle, capt_name, SND_PCM_STREAM_CAPTURE, 0) < 0)
+		{
+			_capt_handle = 0;
+			if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: Cannot open PCM device %s for capture.\n",
+					capt_name);
+		}
+	}
+
+	if (! _play_handle && ! _capt_handle) return;
+
+	if (ctrl_name)
+	{
+		snd_ctl_card_info_alloca (&card);
+
+		if ((err = snd_ctl_open (&_ctrl_handle, ctrl_name, 0)) < 0)
+		{
+			if (_debug & DEBUG_INIT) fprintf  (stderr, "Alse_driver: ctl_open(): %s\n",
+					snd_strerror (err));
+			return;
+		}
+		if ((err = snd_ctl_card_info (_ctrl_handle, card)) < 0)
+		{
+			if (_debug & DEBUG_INIT) fprintf  (stderr, "Alsa_pcmi: ctl_card_info(): %s\n",
+					snd_strerror (err));
+			return;
+		}
+	}
+
+	if (_play_handle)
+	{
+		if (snd_pcm_hw_params_malloc (&_play_hwpar) < 0)
+		{
+			if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: can't allocate playback hw params\n");
+			return;
+		}
+		if (snd_pcm_sw_params_malloc (&_play_swpar) < 0)
+		{
+			if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: can't allocate playback sw params\n");
+			return;
+		}
+		if (set_hwpar (_play_handle, _play_hwpar, "playback", &_play_nchan) < 0) return;
+		if (set_swpar (_play_handle, _play_swpar, "playback") < 0) return;
+	}
+
+	if (_capt_handle)
+	{
+		if (snd_pcm_hw_params_malloc (&_capt_hwpar) < 0)
+		{
+			if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: can't allocate capture hw params\n");
+			return;
+		}
+		if (snd_pcm_sw_params_malloc (&_capt_swpar) < 0)
+		{
+			if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: can't allocate capture sw params\n");
+			return;
+		}
+		if (set_hwpar (_capt_handle, _capt_hwpar, "capture", &_capt_nchan) < 0) return;
+		if (set_swpar (_capt_handle, _capt_swpar, "capture") < 0) return;
+	}
+
+	if (_play_handle)
+	{
+		if (snd_pcm_hw_params_get_rate (_play_hwpar, &fsamp, &dir) || (fsamp != _fsamp) || dir)
+		{
+			if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: can't get requested sample rate for playback.\n");
+			return;
+		}
+		if (snd_pcm_hw_params_get_period_size (_play_hwpar, &fsize, &dir) || (fsize != _fsize) || dir)
+		{
+			if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: can't get requested period size for playback.\n");
+			return;
+		}
+		if (snd_pcm_hw_params_get_periods (_play_hwpar, &nfrag, &dir) || (nfrag != _nfrag) || dir)
+		{
+			if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: can't get requested number of periods for playback.\n");
+			return;
+		}
+
+		snd_pcm_hw_params_get_format (_play_hwpar, &_play_format);
+		snd_pcm_hw_params_get_access (_play_hwpar, &_play_access);
+
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+		switch (_play_format)
+		{
+			case SND_PCM_FORMAT_FLOAT_LE:
+				_clear_func = &Alsa_pcmi::clear_32;
+				_play_func  = &Alsa_pcmi::play_float;
+				break;
+
+			case SND_PCM_FORMAT_S32_LE:
+				_clear_func = &Alsa_pcmi::clear_32;
+				_play_func  = &Alsa_pcmi::play_32;
+				break;
+
+			case SND_PCM_FORMAT_S32_BE:
+				_clear_func = &Alsa_pcmi::clear_32;
+				_play_func  = &Alsa_pcmi::play_32swap;
+				break;
+
+			case SND_PCM_FORMAT_S24_3LE:
+				_clear_func = &Alsa_pcmi::clear_24;
+				_play_func  = &Alsa_pcmi::play_24;
+				break;
+
+			case SND_PCM_FORMAT_S24_3BE:
+				_clear_func = &Alsa_pcmi::clear_24;
+				_play_func  = &Alsa_pcmi::play_24swap;
+				break;
+
+			case SND_PCM_FORMAT_S16_LE:
+				_clear_func = &Alsa_pcmi::clear_16;
+				_play_func  = &Alsa_pcmi::play_16;
+				break;
+
+			case SND_PCM_FORMAT_S16_BE:
+				_clear_func = &Alsa_pcmi::clear_16;
+				_play_func  = &Alsa_pcmi::play_16swap;
+				break;
+
+			default:
+				if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: can't handle playback sample format.\n");
+				return;
+		}
+#elif __BYTE_ORDER == __BIG_ENDIAN
+		switch (_play_format)
+		{
+			case SND_PCM_FORMAT_S32_LE:
+				_clear_func = &Alsa_pcmi::clear_32;
+				_play_func  = &Alsa_pcmi::play_32swap;
+				break;
+
+			case SND_PCM_FORMAT_S32_BE:
+				_clear_func = &Alsa_pcmi::clear_32;
+				_play_func  = &Alsa_pcmi::play_32;
+				break;
+
+			case SND_PCM_FORMAT_S24_3LE:
+				_clear_func = &Alsa_pcmi::clear_24;
+				_play_func  = &Alsa_pcmi::play_24swap;
+				break;
+
+			case SND_PCM_FORMAT_S24_3BE:
+				_clear_func = &Alsa_pcmi::clear_24;
+				_play_func  = &Alsa_pcmi::play_24;
+				break;
+
+			case SND_PCM_FORMAT_S16_LE:
+				_clear_func = &Alsa_pcmi::clear_16;
+				_play_func  = &Alsa_pcmi::play_16swap;
+				break;
+
+			case SND_PCM_FORMAT_S16_BE:
+				_clear_func = &Alsa_pcmi::clear_16;
+				_play_func  = &Alsa_pcmi::play_16;
+				break;
+
+			default:
+				if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: can't handle playback sample format.\n");
+				return;
+		}
+#else
+#error "System byte order is undefined or not supported"
+#endif
+
+		_play_npfd = snd_pcm_poll_descriptors_count (_play_handle);
+	}
+
+	if (_capt_handle)
+	{
+		if (snd_pcm_hw_params_get_rate (_capt_hwpar, &fsamp, &dir) || (fsamp != _fsamp) || dir)
+		{
+			if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: can't get requested sample rate for capture.\n");
+			return;
+		}
+		if (snd_pcm_hw_params_get_period_size (_capt_hwpar, &fsize, &dir) || (fsize != _fsize) || dir)
+		{
+			if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: can't get requested period size for capture.\n");
+			return;
+		}
+		if (snd_pcm_hw_params_get_periods (_capt_hwpar, &nfrag, &dir) || (nfrag != _nfrag) || dir)
+		{
+			if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: can't get requested number of periods for capture.\n");
+			return;
+		}
+
+		if (_play_handle) _synced = ! snd_pcm_link (_play_handle, _capt_handle);
+
+		snd_pcm_hw_params_get_format (_capt_hwpar, &_capt_format);
+		snd_pcm_hw_params_get_access (_capt_hwpar, &_capt_access);
+
+#if __BYTE_ORDER == __LITTLE_ENDIAN
+		switch (_capt_format)
+		{
+			case SND_PCM_FORMAT_FLOAT_LE:
+				_capt_func  = &Alsa_pcmi::capt_float;
+				break;
+
+			case SND_PCM_FORMAT_S32_LE:
+				_capt_func  = &Alsa_pcmi::capt_32;
+				break;
+
+			case SND_PCM_FORMAT_S32_BE:
+				_capt_func  = &Alsa_pcmi::capt_32swap;
+				break;
+
+			case SND_PCM_FORMAT_S24_3LE:
+				_capt_func  = &Alsa_pcmi::capt_24;
+				break;
+
+			case SND_PCM_FORMAT_S24_3BE:
+				_capt_func  = &Alsa_pcmi::capt_24swap;
+				break;
+
+			case SND_PCM_FORMAT_S16_LE:
+				_capt_func  = &Alsa_pcmi::capt_16;
+				break;
+
+			case SND_PCM_FORMAT_S16_BE:
+				_capt_func  = &Alsa_pcmi::capt_16swap;
+				break;
+
+			default:
+				if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: can't handle capture sample format.\n");
+				return;
+		}
+#elif __BYTE_ORDER == __BIG_ENDIAN
+		switch (_capt_format)
+		{
+			case SND_PCM_FORMAT_S32_LE:
+				_capt_func  = &Alsa_pcmi::capt_32swap;
+				break;
+
+			case SND_PCM_FORMAT_S32_BE:
+				_capt_func  = &Alsa_pcmi::capt_32;
+				break;
+
+			case SND_PCM_FORMAT_S24_3LE:
+				_capt_func  = &Alsa_pcmi::capt_24swap;
+				break;
+
+			case SND_PCM_FORMAT_S24_3BE:
+				_capt_func  = &Alsa_pcmi::capt_24;
+				break;
+
+			case SND_PCM_FORMAT_S16_LE:
+				_capt_func  = &Alsa_pcmi::capt_16swap;
+				break;
+
+			case SND_PCM_FORMAT_S16_BE:
+				_capt_func  = &Alsa_pcmi::capt_16;
+				break;
+
+			default:
+				if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: can't handle capture sample format.\n");
+				return;
+		}
+#else
+#error "System byte order is undefined or not supported"
+#endif
+
+		_capt_npfd = snd_pcm_poll_descriptors_count (_capt_handle);
+	}
+
+	if (_play_npfd + _capt_npfd > MAXPFD)
+	{
+		if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: interface requires more than %d pollfd\n", MAXPFD);
+		return;
+	}
+
+	_state = 0;
+}
+
+
+int Alsa_pcmi::set_hwpar (snd_pcm_t *handle,  snd_pcm_hw_params_t *hwpar, const char *sname, unsigned int *nchan)
+{
+	bool err;
+
+	if (snd_pcm_hw_params_any (handle, hwpar) < 0)
+	{
+		if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: no %s hw configurations available.\n",
+				sname);
+		return -1;
+	}
+	if (snd_pcm_hw_params_set_periods_integer (handle, hwpar) < 0)
+	{
+		if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: can't set %s period size to integral value.\n",
+				sname);
+		return -1;
+	}
+	if (   (snd_pcm_hw_params_set_access (handle, hwpar, SND_PCM_ACCESS_MMAP_NONINTERLEAVED) < 0)
+			&& (snd_pcm_hw_params_set_access (handle, hwpar, SND_PCM_ACCESS_MMAP_INTERLEAVED) < 0)
+			&& (snd_pcm_hw_params_set_access (handle, hwpar, SND_PCM_ACCESS_MMAP_COMPLEX) < 0))
+	{
+		if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: the %s interface doesn't support mmap-based access.\n",
+				sname);
+		return -1;
+	}
+	if (_debug & FORCE_16B)
+	{
+		err =    (snd_pcm_hw_params_set_format (handle, hwpar, SND_PCM_FORMAT_S16_LE) < 0)
+			&& (snd_pcm_hw_params_set_format (handle, hwpar, SND_PCM_FORMAT_S16_BE) < 0);
+	}
+	else
+	{
+		err =    (snd_pcm_hw_params_set_format (handle, hwpar, SND_PCM_FORMAT_FLOAT_LE) < 0)
+			&& (snd_pcm_hw_params_set_format (handle, hwpar, SND_PCM_FORMAT_S32_LE) < 0)
+			&& (snd_pcm_hw_params_set_format (handle, hwpar, SND_PCM_FORMAT_S32_BE) < 0)
+			&& (snd_pcm_hw_params_set_format (handle, hwpar, SND_PCM_FORMAT_S24_3LE) < 0)
+			&& (snd_pcm_hw_params_set_format (handle, hwpar, SND_PCM_FORMAT_S24_3BE) < 0)
+			&& (snd_pcm_hw_params_set_format (handle, hwpar, SND_PCM_FORMAT_S16_LE) < 0)
+			&& (snd_pcm_hw_params_set_format (handle, hwpar, SND_PCM_FORMAT_S16_BE) < 0);
+	}
+	if (err)
+	{
+		if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: no supported sample format on %s interface.\n.",
+				sname);
+		return -1;
+	}
+	if (snd_pcm_hw_params_set_rate (handle, hwpar, _fsamp, 0) < 0)
+	{
+		if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: can't set %s sample rate to %u.\n",
+				sname, _fsamp);
+		return -1;
+	}
+	snd_pcm_hw_params_get_channels_max (hwpar, nchan);
+	if (*nchan > 1024)
+	{
+		if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: detected more than 1024 %s channnels, reset to 2.\n",
+				sname);
+		*nchan = 2;
+	}
+	if (_debug & FORCE_2CH)
+	{
+		*nchan = 2;
+	}
+	if (*nchan > MAXCHAN)
+	{
+		if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: number of %s channels reduced to %d.\n",
+				sname, MAXCHAN);
+		*nchan = MAXCHAN;
+	}
+
+	if (snd_pcm_hw_params_set_channels (handle, hwpar, *nchan) < 0)
+	{
+		if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: can't set %s channel count to %u.\n",
+				sname, *nchan);
+		return -1;
+	}
+	if (snd_pcm_hw_params_set_period_size (handle, hwpar, _fsize, 0) < 0)
+	{
+		if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: can't set %s period size to %lu.\n",
+				sname, _fsize);
+		return -1;
+	}
+	if (snd_pcm_hw_params_set_periods (handle, hwpar, _nfrag, 0) < 0)
+	{
+		if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: can't set %s periods to %u.\n",
+				sname, _nfrag);
+		return -1;
+	}
+	if (snd_pcm_hw_params_set_buffer_size (handle, hwpar, _fsize * _nfrag) < 0)
+	{
+		if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: can't set %s buffer length to %lu.\n",
+				sname, _fsize * _nfrag);
+		return -1;
+	}
+	if (snd_pcm_hw_params (handle, hwpar) < 0)
+	{
+		if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: can't set %s hardware parameters.\n",
+				sname);
+		return -1;
+	}
+
+	return 0;
+}
+
+
+int Alsa_pcmi::set_swpar (snd_pcm_t *handle, snd_pcm_sw_params_t *swpar, const char *sname)
+{
+	int err;
+
+	snd_pcm_sw_params_current (handle, swpar);
+
+	if ((err = snd_pcm_sw_params_set_tstamp_mode (handle, swpar, SND_PCM_TSTAMP_MMAP)) < 0)
+	{
+		if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: can't set %s timestamp mode to %u.\n",
+				sname, SND_PCM_TSTAMP_MMAP);
+		return -1;
+	}
+	if ((err = snd_pcm_sw_params_set_avail_min (handle, swpar, _fsize)) < 0)
+	{
+		if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: can't set %s avail_min to %lu.\n",
+				sname, _fsize);
+		return -1;
+	}
+	if ((err = snd_pcm_sw_params (handle, swpar)) < 0)
+	{
+		if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: can't set %s software parameters.\n",
+				sname);
+		return -1;
+	}
+
+	return 0;
+}
+
+
+int Alsa_pcmi::recover (void)
+{
+	int                err;
+	snd_pcm_status_t   *stat;
+
+	snd_pcm_status_alloca (&stat);
+
+	if (_play_handle)
+	{
+		if ((err = snd_pcm_status (_play_handle, stat)) < 0)
+		{
+			if (_debug & DEBUG_STAT) fprintf (stderr, "Alsa_pcmi: pcm_status(play): %s\n",
+					snd_strerror (err));
+		}
+		_play_xrun = xruncheck (stat);
+	}
+	if (_capt_handle)
+	{
+		if ((err = snd_pcm_status (_capt_handle, stat)) < 0)
+		{
+			if (_debug & DEBUG_STAT) fprintf (stderr, "Alsa_pcmi: pcm_status(capt): %s\n",
+					snd_strerror (err));
+		}
+		_capt_xrun = xruncheck (stat);
+	}
+
+	if (pcm_stop ()) return -1;
+	if (_play_handle && ((err = snd_pcm_prepare (_play_handle)) < 0))
+	{
+		if (_debug & DEBUG_STAT) fprintf (stderr, "Alsa_pcmi: pcm_prepare(play): %s\n",
+				snd_strerror (err));
+		return -1;
+	}
+	if (_capt_handle && !_synced && ((err = snd_pcm_prepare (_capt_handle)) < 0))
+	{
+		if (_debug & DEBUG_INIT) fprintf (stderr, "Alsa_pcmi: pcm_prepare(capt): %s\n",
+				snd_strerror (err));
+		return -1;
+	}
+	if (pcm_start ()) return -1;
+
+	return 0;
+}
+
+
+float Alsa_pcmi::xruncheck (snd_pcm_status_t *stat)
+{
+	struct timeval   tupd, trig;
+	int              ds, du;
+
+	if (snd_pcm_status_get_state (stat) == SND_PCM_STATE_XRUN)
+	{
+		snd_pcm_status_get_tstamp (stat, &tupd);
+		snd_pcm_status_get_trigger_tstamp (stat, &trig);
+		ds = tupd.tv_sec - trig.tv_sec;
+		du = tupd.tv_usec - trig.tv_usec;
+		if (du < 0)
+		{
+			du += 1000000;
+			ds -= 1;
+		}
+		return ds + 1e-6f * du;
+	}
+	return 0.0f;
+}
+
+
+char *Alsa_pcmi::clear_16 (char *dst, int nfrm)
+{
+	while (nfrm--)
+	{
+		*((short int *) dst) = 0;
+		dst += _play_step;
+	}
+	return dst;
+}
+
+char *Alsa_pcmi::clear_24 (char *dst, int nfrm)
+{
+	while (nfrm--)
+	{
+		dst [0] = 0;
+		dst [1] = 0;
+		dst [2] = 0;
+		dst += _play_step;
+	}
+	return dst;
+}
+
+char *Alsa_pcmi::clear_32 (char *dst, int nfrm)
+{
+	while (nfrm--)
+	{
+		*((int *) dst) = 0;
+		dst += _play_step;
+	}
+	return dst;
+}
+
+
+char *Alsa_pcmi::play_16 (const float *src, char *dst, int nfrm, int step)
+{
+	float     s;
+	short int d;
+
+	while (nfrm--)
+	{
+		s = *src;
+		if      (s >  1) d = 0x7fff;
+		else if (s < -1) d = 0x8001;
+		else d = (short int)((float) 0x7fff * s);
+		*((short int *) dst) = d;
+		dst += _play_step;
+		src += step;
+	}
+	return dst;
+}
+
+char *Alsa_pcmi::play_16swap (const float *src, char *dst, int nfrm, int step)
+{
+	float     s;
+	short int d;
+
+	while (nfrm--)
+	{
+		s = *src;
+		if      (s >  1) d = 0x7fff;
+		else if (s < -1) d = 0x8001;
+		else d = (short int)((float) 0x7fff * s);
+		dst [0] = d >> 8;
+		dst [1] = d;
+		dst += _play_step;
+		src += step;
+	}
+	return dst;
+}
+
+char *Alsa_pcmi::play_24 (const float *src, char *dst, int nfrm, int step)
+{
+	float   s;
+	int     d;
+
+	while (nfrm--)
+	{
+		s = *src;
+		if      (s >  1) d = 0x007fffff;
+		else if (s < -1) d = 0x00800001;
+		else d = (int)((float) 0x007fffff * s);
+		dst [0] = d;
+		dst [1] = d >> 8;
+		dst [2] = d >> 16;
+		dst += _play_step;
+		src += step;
+	}
+	return dst;
+}
+
+char *Alsa_pcmi::play_24swap (const float *src, char *dst, int nfrm, int step)
+{
+	float   s;
+	int     d;
+
+	while (nfrm--)
+	{
+		s = *src;
+		if      (s >  1) d = 0x007fffff;
+		else if (s < -1) d = 0x00800001;
+		else d = (int)((float) 0x007fffff * s);
+		dst [0] = d >> 16;
+		dst [1] = d >> 8;
+		dst [2] = d;
+		dst += _play_step;
+		src += step;
+	}
+	return dst;
+}
+
+char *Alsa_pcmi::play_32 (const float *src, char *dst, int nfrm, int step)
+{
+	float   s;
+	int     d;
+
+	while (nfrm--)
+	{
+		s = *src;
+		if      (s >  1) d = 0x007fffff;
+		else if (s < -1) d = 0x00800001;
+		else d = (int)((float) 0x007fffff * s);
+		*((int *) dst) = d << 8;
+		dst += _play_step;
+		src += step;
+	}
+	return dst;
+}
+
+char *Alsa_pcmi::play_32swap (const float *src, char *dst, int nfrm, int step)
+{
+	float   s;
+	int     d;
+
+	while (nfrm--)
+	{
+		s = *src;
+		if      (s >  1) d = 0x007fffff;
+		else if (s < -1) d = 0x00800001;
+		else d = (int)((float) 0x007fffff * s);
+		dst [0] = d >> 16;
+		dst [1] = d >> 8;
+		dst [2] = d;
+		dst [3] = 0;
+		dst += _play_step;
+		src += step;
+	}
+	return dst;
+}
+
+char *Alsa_pcmi::play_float (const float *src, char *dst, int nfrm, int step)
+{
+	while (nfrm--)
+	{
+		*((float *) dst) = *src;
+		dst += _play_step;
+		src += step;
+	}
+	return dst;
+}
+
+
+const char *Alsa_pcmi::capt_16 (const char *src, float *dst, int nfrm, int step)
+{
+	while (nfrm--)
+	{
+		const short int s = *((short int const *) src);
+		const float d = (float) s / (float) 0x7fff;
+		*dst = d;
+		dst += step;
+		src += _capt_step;
+	}
+	return src;
+}
+
+const char *Alsa_pcmi::capt_16swap (const char *src, float *dst, int nfrm, int step)
+{
+	float     d;
+	short int s;
+
+	while (nfrm--)
+	{
+		s =  (src [0] & 0xFF) << 8;
+		s += (src [1] & 0xFF);
+		d = (float) s / (float) 0x7fff;
+		*dst = d;
+		dst += step;
+		src += _capt_step;
+	}
+	return src;
+}
+
+const char *Alsa_pcmi::capt_24 (const char *src, float *dst, int nfrm, int step)
+{
+	float   d;
+	int     s;
+
+	while (nfrm--)
+	{
+		s  = (src [0] & 0xFF);
+		s += (src [1] & 0xFF) << 8;
+		s += (src [2] & 0xFF) << 16;
+		if (s & 0x00800000) s-= 0x01000000;
+		d = (float) s / (float) 0x007fffff;
+		*dst = d;
+		dst += step;
+		src += _capt_step;
+	}
+	return src;
+}
+
+const char *Alsa_pcmi::capt_24swap (const char *src, float *dst, int nfrm, int step)
+{
+	float   d;
+	int     s;
+
+	while (nfrm--)
+	{
+		s  = (src [0] & 0xFF) << 16;
+		s += (src [1] & 0xFF) << 8;
+		s += (src [2] & 0xFF);
+		if (s & 0x00800000) s-= 0x01000000;
+		d = (float) s / (float) 0x007fffff;
+		*dst = d;
+		dst += step;
+		src += _capt_step;
+	}
+	return src;
+}
+
+const char *Alsa_pcmi::capt_32 (const char *src, float *dst, int nfrm, int step)
+{
+	while (nfrm--)
+	{
+		const int s = *((int const *) src);
+		const float d = (float) s / (float) 0x7fffff00;
+		*dst = d;
+		dst += step;
+		src += _capt_step;
+	}
+	return src;
+}
+
+const char *Alsa_pcmi::capt_32swap (const char *src, float *dst, int nfrm, int step)
+{
+	float   d;
+	int     s;
+
+	while (nfrm--)
+	{
+		s  = (src [0] & 0xFF) << 24;
+		s += (src [1] & 0xFF) << 16;
+		s += (src [2] & 0xFF) << 8;
+		d = (float) s / (float) 0x7fffff00;
+		*dst = d;
+		dst += step;
+		src += _capt_step;
+	}
+	return src;
+}
+
+const char *Alsa_pcmi::capt_float (const char *src, float *dst, int nfrm, int step)
+{
+	while (nfrm--)
+	{
+		*dst = *((float const *) src);
+		dst += step;
+		src += _capt_step;
+	}
+	return src;
+}