/*
 *  PCM Plug-In shared (kernel/library) code
 *  Copyright (c) 1999 by Jaroslav Kysela <perex@suse.cz>
 *  Copyright (c) 2000 by Abramo Bagnara <abramo@alsa-project.org>
 *
 *
 *   This library is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Library General Public License as
 *   published by the Free Software Foundation; either version 2 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 Library General Public License for more details.
 *
 *   You should have received a copy of the GNU Library General Public
 *   License along with this library; if not, write to the Free Software
 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */
  
#if 0
#define PLUGIN_DEBUG
#endif
#ifdef __KERNEL__
#include "../../include/driver.h"
#include "../../include/pcm.h"
#define snd_pcm_plug_first(plug) ((plug)->runtime->oss.plugin_first)
#define snd_pcm_plug_last(plug) ((plug)->runtime->oss.plugin_last)
#define __vmalloc snd_vmalloc
#define __vfree snd_vfree
#else
#include <malloc.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <sys/uio.h>
#include "pcm_local.h"
#define snd_pcm_plug_first(plug) ((plug)->first)
#define snd_pcm_plug_last(plug) ((plug)->last)
#define __vmalloc malloc
#define __vfree free
#endif

static int snd_pcm_plugin_src_channels_mask(snd_pcm_plugin_t *plugin,
					    bitset_t *dst_vmask,
					    bitset_t **src_vmask)
{
	bitset_t *vmask = plugin->src_vmask;
	bitset_copy(vmask, dst_vmask, plugin->src_format.channels);
	*src_vmask = vmask;
	return 0;
}

static int snd_pcm_plugin_dst_channels_mask(snd_pcm_plugin_t *plugin,
					    bitset_t *src_vmask,
					    bitset_t **dst_vmask)
{
	bitset_t *vmask = plugin->dst_vmask;
	bitset_copy(vmask, src_vmask, plugin->dst_format.channels);
	*dst_vmask = vmask;
	return 0;
}

static int snd_pcm_plugin_alloc(snd_pcm_plugin_t *plugin, size_t frames)
{
	snd_pcm_format_t *format;
	ssize_t width;
	size_t size;
	unsigned int channel;
	snd_pcm_plugin_channel_t *c;
	if (plugin->stream == SND_PCM_STREAM_PLAYBACK)
		format = &plugin->src_format;
	else
		format = &plugin->dst_format;
	if ((width = snd_pcm_format_physical_width(format->format)) < 0)
		return width;
	size = frames * format->channels * width;
	assert(size % 8 == 0);
	size /= 8;
	if (plugin->buf_frames < frames) {
		if (plugin->buf)
			__vfree(plugin->buf);
		plugin->buf = __vmalloc(size);
		plugin->buf_frames = frames;
	}
	if (!plugin->buf)
		return -ENOMEM;
	c = plugin->buf_channels;
	if (format->interleave) {
		for (channel = 0; channel < format->channels; channel++, c++) {
			c->enabled = 1;
			c->wanted = 0;
			c->area.addr = plugin->buf;
			c->area.first = channel * width;
			c->area.step = format->channels * width;
		}
	} else {
		assert(size % format->channels == 0);
		size /= format->channels;
		for (channel = 0; channel < format->channels; channel++, c++) {
			c->enabled = 1;
			c->wanted = 0;
			c->area.addr = plugin->buf + (channel * size);
			c->area.first = 0;
			c->area.step = width;
		}
	}
	return 0;
}

int snd_pcm_plug_alloc(snd_pcm_plug_t *plug, size_t frames)
{
	int err;
#ifndef __KERNEL__
	plug->frames_alloc = frames;
#endif
	assert(snd_pcm_plug_first(plug));
	if (snd_pcm_plug_stream(plug) == SND_PCM_STREAM_PLAYBACK) {
		snd_pcm_plugin_t *plugin = snd_pcm_plug_first(plug);
		while (plugin->next) {
			if (plugin->dst_frames)
				frames = plugin->dst_frames(plugin, frames);
			assert(frames > 0);
			plugin = plugin->next;
			err = snd_pcm_plugin_alloc(plugin, frames);
			if (err < 0)
				return err;
		}
	} else {
		snd_pcm_plugin_t *plugin = snd_pcm_plug_last(plug);
		while (plugin->prev) {
			if (plugin->src_frames)
				frames = plugin->src_frames(plugin, frames);
			assert(frames > 0);
			plugin = plugin->prev;
			err = snd_pcm_plugin_alloc(plugin, frames);
			if (err < 0)
				return err;
		}
	}
	return 0;
}


ssize_t snd_pcm_plugin_client_channels(snd_pcm_plugin_t *plugin,
				       size_t frames,
				       snd_pcm_plugin_channel_t **channels)
{
	assert(frames <= plugin->buf_frames);
	*channels = plugin->buf_channels;
	return frames;
}

int snd_pcm_plugin_build(snd_pcm_plug_t *plug,
			 const char *name,
			 snd_pcm_format_t *src_format,
			 snd_pcm_format_t *dst_format,
			 size_t extra,
			 snd_pcm_plugin_t **ret)
{
	snd_pcm_plugin_t *plugin;
	size_t channels;
	
	assert(plug);
	assert(src_format && dst_format);
	plugin = (snd_pcm_plugin_t *)calloc(1, sizeof(*plugin) + extra);
	if (plugin == NULL)
		return -ENOMEM;
	plugin->name = name ? strdup(name) : NULL;
	plugin->plug = plug;
	plugin->stream = snd_pcm_plug_stream(plug);
	plugin->src_format = *src_format;
	plugin->src_width = snd_pcm_format_physical_width(src_format->format);
	assert(plugin->src_width > 0);
	plugin->dst_format = *dst_format;
	plugin->dst_width = snd_pcm_format_physical_width(dst_format->format);
	assert(plugin->dst_width > 0);
	if (plugin->stream == SND_PCM_STREAM_PLAYBACK)
		channels = src_format->channels;
	else
		channels = dst_format->channels;
	plugin->buf_channels = calloc(channels, sizeof(*plugin->buf_channels));
	if (plugin->buf_channels == NULL) {
		free(plugin);
		return -ENOMEM;
	}
	plugin->src_vmask = bitset_alloc(src_format->channels);
	if (plugin->src_vmask == NULL) {
		free(plugin->buf_channels);
		free(plugin);
		return -ENOMEM;
	}
	plugin->dst_vmask = bitset_alloc(dst_format->channels);
	if (plugin->dst_vmask == NULL) {
		free(plugin->buf_channels);
		free(plugin->src_vmask);
		free(plugin);
		return -ENOMEM;
	}
	plugin->client_channels = snd_pcm_plugin_client_channels;
	plugin->src_channels_mask = snd_pcm_plugin_src_channels_mask;
	plugin->dst_channels_mask = snd_pcm_plugin_dst_channels_mask;
	*ret = plugin;
	return 0;
}

int snd_pcm_plugin_free(snd_pcm_plugin_t *plugin)
{
	assert(plugin);
	if (plugin->private_free)
		plugin->private_free(plugin);
	if (plugin->name)
		free(plugin->name);
	free(plugin->buf_channels);
	if (plugin->buf)
		__vfree(plugin->buf);
	free(plugin->src_vmask);
	free(plugin->dst_vmask);
	free(plugin);
	return 0;
}

ssize_t snd_pcm_plug_client_size(snd_pcm_plug_t *plug, size_t drv_frames)
{
	snd_pcm_plugin_t *plugin, *plugin_prev, *plugin_next;
	int stream = snd_pcm_plug_stream(plug);

	assert(plug);
	if (drv_frames == 0)
		return 0;
	if (stream == SND_PCM_STREAM_PLAYBACK) {
		plugin = snd_pcm_plug_last(plug);
		while (plugin && drv_frames > 0) {
			plugin_prev = plugin->prev;
			if (plugin->src_frames)
				drv_frames = plugin->src_frames(plugin, drv_frames);
			plugin = plugin_prev;
		}
	} else if (stream == SND_PCM_STREAM_CAPTURE) {
		plugin = snd_pcm_plug_first(plug);
		while (plugin && drv_frames > 0) {
			plugin_next = plugin->next;
			if (plugin->dst_frames)
				drv_frames = plugin->dst_frames(plugin, drv_frames);
			plugin = plugin_next;
		}
	} else
		assert(0);
	return drv_frames;
}

ssize_t snd_pcm_plug_slave_size(snd_pcm_plug_t *plug, size_t clt_frames)
{
	snd_pcm_plugin_t *plugin, *plugin_prev, *plugin_next;
	ssize_t frames;
	int stream = snd_pcm_plug_stream(plug);
	
	assert(plug);
	if (clt_frames == 0)
		return 0;
	frames = clt_frames;
	if (stream == SND_PCM_STREAM_PLAYBACK) {
		plugin = snd_pcm_plug_first(plug);
		while (plugin && frames > 0) {
			plugin_next = plugin->next;
			if (plugin->dst_frames) {
				frames = plugin->dst_frames(plugin, frames);
				if (frames < 0)
					return frames;
			}
			plugin = plugin_next;
		}
	} else if (stream == SND_PCM_STREAM_CAPTURE) {
		plugin = snd_pcm_plug_last(plug);
		while (plugin) {
			plugin_prev = plugin->prev;
			if (plugin->src_frames) {
				frames = plugin->src_frames(plugin, frames);
				if (frames < 0)
					return frames;
			}
			plugin = plugin_prev;
		}
	} else
		assert(0);
	return frames;
}

unsigned int snd_pcm_plug_formats(unsigned int formats)
{
	int linfmts = (SND_PCM_FMT_U8 | SND_PCM_FMT_S8 |
		       SND_PCM_FMT_U16_LE | SND_PCM_FMT_S16_LE |
		       SND_PCM_FMT_U16_BE | SND_PCM_FMT_S16_BE |
		       SND_PCM_FMT_U24_LE | SND_PCM_FMT_S24_LE |
		       SND_PCM_FMT_U24_BE | SND_PCM_FMT_S24_BE |
		       SND_PCM_FMT_U32_LE | SND_PCM_FMT_S32_LE |
		       SND_PCM_FMT_U32_BE | SND_PCM_FMT_S32_BE);
	formats |= SND_PCM_FMT_MU_LAW;
#ifndef __KERNEL__
	formats |= SND_PCM_FMT_A_LAW | SND_PCM_FMT_IMA_ADPCM;
#endif
	
	if (formats & linfmts)
		formats |= linfmts;
	return formats;
}

static int preferred_formats[] = {
	SND_PCM_SFMT_S16_LE,
	SND_PCM_SFMT_S16_BE,
	SND_PCM_SFMT_U16_LE,
	SND_PCM_SFMT_U16_BE,
	SND_PCM_SFMT_S24_LE,
	SND_PCM_SFMT_S24_BE,
	SND_PCM_SFMT_U24_LE,
	SND_PCM_SFMT_U24_BE,
	SND_PCM_SFMT_S32_LE,
	SND_PCM_SFMT_S32_BE,
	SND_PCM_SFMT_U32_LE,
	SND_PCM_SFMT_U32_BE,
	SND_PCM_SFMT_S8,
	SND_PCM_SFMT_U8
};

int snd_pcm_plug_slave_fmt(int format, snd_pcm_params_info_t *slave_info)
{
	if ((snd_pcm_plug_formats(slave_info->formats) & (1 << format)) == 0)
		return -EINVAL;
	if (snd_pcm_format_linear(format)) {
		int width = snd_pcm_format_width(format);
		int unsignd = snd_pcm_format_unsigned(format);
		int big = snd_pcm_format_big_endian(format);
		int format1;
		int wid, width1=width;
		int dwidth1 = 8;
		for (wid = 0; wid < 4; ++wid) {
			int end, big1 = big;
			for (end = 0; end < 2; ++end) {
				int sgn, unsignd1 = unsignd;
				for (sgn = 0; sgn < 2; ++sgn) {
					format1 = snd_pcm_build_linear_format(width1, unsignd1, big1);
					if (format1 >= 0 &&
					    slave_info->formats & (1 << format1))
						goto _found;
					unsignd1 = !unsignd1;
				}
				big1 = !big1;
			}
			if (width1 == 32) {
				dwidth1 = -dwidth1;
				width1 = width;
			}
			width1 += dwidth1;
		}
		return -EINVAL;
	_found:
		return format1;
	} else {
		unsigned int i;
		switch (format) {
		case SND_PCM_SFMT_MU_LAW:
#ifndef __KERNEL__
		case SND_PCM_SFMT_A_LAW:
		case SND_PCM_SFMT_IMA_ADPCM:
#endif
			for (i = 0; i < sizeof(preferred_formats) / sizeof(preferred_formats[0]); ++i) {
				int format1 = preferred_formats[i];
				if (slave_info->formats & (1 << format1))
					return format1;
			}
		default:
			return -EINVAL;
		}
	}
}

struct {
	unsigned int rate;
	unsigned int flag;
} snd_pcm_rates[] = {
	{ 8000, SND_PCM_RATE_8000 },
	{ 11025, SND_PCM_RATE_11025 },
	{ 16000, SND_PCM_RATE_16000 },
	{ 22050, SND_PCM_RATE_22050 },
	{ 32000, SND_PCM_RATE_32000 },
	{ 44100, SND_PCM_RATE_44100 },
	{ 48000, SND_PCM_RATE_48000 },
	{ 88200, SND_PCM_RATE_88200 },
	{ 96000, SND_PCM_RATE_96000 },
	{ 176400, SND_PCM_RATE_176400 },
	{ 192000, SND_PCM_RATE_192000 }
};

int snd_pcm_plug_slave_rate(unsigned int rate, snd_pcm_params_info_t *slave_info)
{
        if (rate <= slave_info->min_rate)
		return slave_info->min_rate;
	else if (rate >= slave_info->max_rate)
		return slave_info->max_rate;
	else if (!(slave_info->rates & (SND_PCM_RATE_CONTINUOUS |
					       SND_PCM_RATE_KNOT))) {
		unsigned int k;
		unsigned int rate1 = 0, rate2 = 0;
		int delta1, delta2;
		for (k = 0; k < sizeof(snd_pcm_rates) / 
			     sizeof(snd_pcm_rates[0]); ++k) {
			if (!(snd_pcm_rates[k].flag & slave_info->rates))
				continue;
			if (snd_pcm_rates[k].rate < rate) {
				rate1 = snd_pcm_rates[k].rate;
			} else if (snd_pcm_rates[k].rate >= rate) {
				rate2 = snd_pcm_rates[k].rate;
				break;
			}
		}
		if (rate1 == 0)
			return rate2;
		if (rate2 == 0)
			return rate1;
		delta1 = rate - rate1;
		delta2 = rate2 - rate;
		if (delta1 < delta2)
			return rate1;
		else
			return rate2;
	}
	return rate;
}
		   
int snd_pcm_plug_slave_format(snd_pcm_format_t *format,
			      snd_pcm_info_t *slave_info,
			      snd_pcm_params_info_t *slave_params_info,
			      snd_pcm_format_t *slave_format)
{
	int slave_rate;
	*slave_format = *format;
	if ((slave_params_info->formats & (1 << format->format)) == 0) {
		int slave_fmt = snd_pcm_plug_slave_fmt(format->format, slave_params_info);
		if (slave_fmt < 0)
			return slave_fmt;
		slave_format->format = slave_fmt;
	}

	/* channels */
      	if (format->channels < slave_params_info->min_channels)
		slave_format->channels = slave_params_info->min_channels;
	else if (format->channels > slave_params_info->max_channels)
		slave_format->channels = slave_params_info->max_channels;

	/* rate */
	slave_rate = snd_pcm_plug_slave_rate(format->rate, slave_params_info);
	if (slave_rate < 0)
		return slave_rate;
	slave_format->rate = slave_rate;
		   
	/* interleave */
	if (!(slave_info->flags & SND_PCM_INFO_INTERLEAVE))
		slave_format->interleave = 0;
	if (!(slave_info->flags & SND_PCM_INFO_NONINTERLEAVE))
		slave_format->interleave = 1;
	return 0;
}

int snd_pcm_plug_format_plugins(snd_pcm_plug_t *plug, 
				snd_pcm_format_t *format, 
				snd_pcm_format_t *slave_format)
{
	snd_pcm_format_t tmpformat;
	snd_pcm_format_t dstformat;
	snd_pcm_format_t *srcformat;
	snd_pcm_plugin_t *plugin;
	int err;
	
	switch (snd_pcm_plug_stream(plug)) {
	case SND_PCM_STREAM_PLAYBACK:
		dstformat = *slave_format;
		srcformat = slave_format;
		*srcformat = *format;
		break;
	case SND_PCM_STREAM_CAPTURE:
		dstformat = *format;
		srcformat = format;
		*srcformat = *slave_format;
		break;
	default:
		assert(0);
		return -EINVAL;
	}
	tmpformat = *srcformat;
		
	pdprintf("srcformat: interleave=%i, format=%i, rate=%i, channels=%i\n", 
		 srcformat->interleave,
		 srcformat->format,
		 srcformat->rate,
		 srcformat->channels);
	pdprintf("dstformat: interleave=%i, format=%i, rate=%i, channels=%i\n", 
		 dstformat.interleave,
		 dstformat.format,
		 dstformat.rate,
		 dstformat.channels);

	if (srcformat->channels == 1)
		srcformat->interleave = dstformat.interleave;

	/* Format change (linearization) */
	if ((srcformat->format != dstformat.format ||
	     srcformat->rate != dstformat.rate ||
	     srcformat->channels != dstformat.channels) &&
	    !snd_pcm_format_linear(srcformat->format)) {
		if (snd_pcm_format_linear(dstformat.format))
			tmpformat.format = dstformat.format;
		else
			tmpformat.format = SND_PCM_SFMT_S16;
		tmpformat.interleave = dstformat.interleave;
		switch (srcformat->format) {
		case SND_PCM_SFMT_MU_LAW:
			err = snd_pcm_plugin_build_mulaw(plug,
							 srcformat, &tmpformat,
							 &plugin);
			break;
#ifndef __KERNEL__
		case SND_PCM_SFMT_A_LAW:
			err = snd_pcm_plugin_build_alaw(plug,
							srcformat, &tmpformat,
							&plugin);
			break;
		case SND_PCM_SFMT_IMA_ADPCM:
			err = snd_pcm_plugin_build_adpcm(plug,
							 srcformat, &tmpformat,
							 &plugin);
			break;
#endif
		default:
			return -EINVAL;
		}
		pdprintf("format format change: src=%i, dst=%i returns %i\n", srcformat->format, tmpformat.format, err);
		if (err < 0)
			return err;
		err = snd_pcm_plugin_append(plugin);
		if (err < 0) {
			snd_pcm_plugin_free(plugin);
			return err;
		}
		*srcformat = tmpformat;
	}

	/* channels reduction */
	if (srcformat->channels > dstformat.channels) {
		int sv = srcformat->channels;
		int dv = dstformat.channels;
		route_ttable_entry_t *ttable = calloc(1, dv*sv*sizeof(*ttable));
#if 1
		if (sv == 2 && dv == 1) {
			ttable[0] = HALF;
			ttable[1] = HALF;
		} else
#endif
		{
			int v;
			for (v = 0; v < dv; ++v)
				ttable[v * sv + v] = FULL;
		}
		tmpformat.channels = dstformat.channels;
		tmpformat.interleave = dstformat.interleave;
		if (srcformat->rate == dstformat.rate &&
		    snd_pcm_format_linear(dstformat.format))
			tmpformat.format = dstformat.format;
		err = snd_pcm_plugin_build_route(plug,
						 srcformat, &tmpformat,
						 ttable, &plugin);
		free(ttable);
		pdprintf("format channels reduction: src=%i, dst=%i returns %i\n", srcformat->channels, tmpformat.channels, err);
		if (err < 0) {
			snd_pcm_plugin_free(plugin);
			return err;
		}
		err = snd_pcm_plugin_append(plugin);
		if (err < 0) {
			snd_pcm_plugin_free(plugin);
			return err;
		}
		*srcformat = tmpformat;
	}

	/* rate resampling */
	if (srcformat->rate != dstformat.rate) {
		tmpformat.rate = dstformat.rate;
		tmpformat.interleave = dstformat.interleave;
		if (srcformat->channels == dstformat.channels &&
		    snd_pcm_format_linear(dstformat.format))
			tmpformat.format = dstformat.format;
        	err = snd_pcm_plugin_build_rate(plug,
        					srcformat, &tmpformat,
						&plugin);
		pdprintf("format rate down resampling: src=%i, dst=%i returns %i\n", srcformat->rate, tmpformat.rate, err);
		if (err < 0) {
			snd_pcm_plugin_free(plugin);
			return err;
		}      					    
		err = snd_pcm_plugin_append(plugin);
		if (err < 0) {
			snd_pcm_plugin_free(plugin);
			return err;
		}
		*srcformat = tmpformat;
        }

	/* channels extension  */
	if (srcformat->channels < dstformat.channels) {
		int sv = srcformat->channels;
		int dv = dstformat.channels;
		route_ttable_entry_t *ttable = calloc(1, dv * sv * sizeof(*ttable));
#if 0
		{
			int v;
			for (v = 0; v < sv; ++v)
				ttable[v * sv + v] = FULL;
		}
#else
		{
			/* Playback is spreaded on all channels */
			int vd, vs;
			for (vd = 0, vs = 0; vd < dv; ++vd) {
				ttable[vd * sv + vs] = FULL;
				vs++;
				if (vs == sv)
					vs = 0;
			}
		}
#endif
		tmpformat.channels = dstformat.channels;
		tmpformat.interleave = dstformat.interleave;
		if (snd_pcm_format_linear(dstformat.format))
			tmpformat.format = dstformat.format;
		err = snd_pcm_plugin_build_route(plug,
						 srcformat, &tmpformat,
						 ttable, &plugin);
		free(ttable);
		pdprintf("format channels extension: src=%i, dst=%i returns %i\n", srcformat->channels, tmpformat.channels, err);
		if (err < 0) {
			snd_pcm_plugin_free(plugin);
			return err;
		}      					    
		err = snd_pcm_plugin_append(plugin);
		if (err < 0) {
			snd_pcm_plugin_free(plugin);
			return err;
		}
		*srcformat = tmpformat;
	}

	/* format change */
	if (srcformat->format != dstformat.format) {
		tmpformat.format = dstformat.format;
		tmpformat.interleave = dstformat.interleave;
		if (tmpformat.format == SND_PCM_SFMT_MU_LAW) {
			err = snd_pcm_plugin_build_mulaw(plug,
							 srcformat, &tmpformat,
							 &plugin);
		}
#ifndef __KERNEL__
		else if (tmpformat.format == SND_PCM_SFMT_A_LAW) {
			err = snd_pcm_plugin_build_alaw(plug,
							srcformat, &tmpformat,
							&plugin);
		}
		else if (tmpformat.format == SND_PCM_SFMT_IMA_ADPCM) {
			err = snd_pcm_plugin_build_adpcm(plug,
							 srcformat, &tmpformat,
							 &plugin);
		}
#endif
		else if (snd_pcm_format_linear(srcformat->format) &&
			 snd_pcm_format_linear(tmpformat.format)) {
			err = snd_pcm_plugin_build_linear(plug,
							  srcformat, &tmpformat,
							  &plugin);
		}
		else
			return -EINVAL;
		pdprintf("format format change: src=%i, dst=%i returns %i\n", srcformat->format, tmpformat.format, err);
		if (err < 0)
			return err;
		err = snd_pcm_plugin_append(plugin);
		if (err < 0) {
			snd_pcm_plugin_free(plugin);
			return err;
		}
		*srcformat = tmpformat;
	}

	/* interleave */
	if (srcformat->interleave != dstformat.interleave) {
		tmpformat.interleave = dstformat.interleave;
		err = snd_pcm_plugin_build_copy(plug,
						srcformat, &tmpformat,
						&plugin);
		pdprintf("interleave change: src=%i, dst=%i returns %i\n", srcformat->interleave, tmpformat.interleave, err);
		if (err < 0)
			return err;
		err = snd_pcm_plugin_append(plugin);
		if (err < 0) {
			snd_pcm_plugin_free(plugin);
			return err;
		}
		*srcformat = tmpformat;
	}

	return 0;
}

ssize_t snd_pcm_plug_client_channels_buf(snd_pcm_plug_t *plug,
					 char *buf,
					 size_t count,
					 snd_pcm_plugin_channel_t **channels)
{
	snd_pcm_plugin_t *plugin;
	snd_pcm_plugin_channel_t *v;
	snd_pcm_format_t *format;
	int width, nchannels, channel;
	int stream = snd_pcm_plug_stream(plug);

	assert(buf);
	if (stream == SND_PCM_STREAM_PLAYBACK) {
		plugin = snd_pcm_plug_first(plug);
		format = &plugin->src_format;
	}
	else {
		plugin = snd_pcm_plug_last(plug);
		format = &plugin->dst_format;
	}
	v = plugin->buf_channels;
	*channels = v;
	if ((width = snd_pcm_format_physical_width(format->format)) < 0)
		return width;
	nchannels = format->channels;
	assert(format->interleave || format->channels == 1);
	for (channel = 0; channel < nchannels; channel++, v++) {
		v->enabled = 1;
		v->wanted = (stream == SND_PCM_STREAM_CAPTURE);
		v->area.addr = buf;
		v->area.first = channel * width;
		v->area.step = nchannels * width;
	}
	return count;
}

ssize_t snd_pcm_plug_client_channels_iovec(snd_pcm_plug_t *plug,
					   const struct iovec *vector,
					   unsigned long count,
					   snd_pcm_plugin_channel_t **channels)
{
	snd_pcm_plugin_t *plugin;
	snd_pcm_plugin_channel_t *v;
	snd_pcm_format_t *format;
	int width;
	unsigned int nchannels, channel;
	int stream = snd_pcm_plug_stream(plug);

	if (stream == SND_PCM_STREAM_PLAYBACK) {
		plugin = snd_pcm_plug_first(plug);
		format = &plugin->src_format;
	}
	else {
		plugin = snd_pcm_plug_last(plug);
		format = &plugin->dst_format;
	}
	v = plugin->buf_channels;
	*channels = v;
	if ((width = snd_pcm_format_physical_width(format->format)) < 0)
		return width;
	nchannels = format->channels;
	if (format->interleave) {
		assert(count == 1 && vector->iov_base);
		
		for (channel = 0; channel < nchannels; channel++, v++) {
			v->enabled = 1;
			v->wanted = (stream == SND_PCM_STREAM_CAPTURE);
			v->area.addr = vector->iov_base;
			v->area.first = channel * width;
			v->area.step = nchannels * width;
		}
		return vector->iov_len;
	} else {
		size_t len;
		assert(count == nchannels);
		len = vector->iov_len;
		for (channel = 0; channel < nchannels; channel++, v++, vector++) {
			assert(vector->iov_len == len);
			v->enabled = (vector->iov_base != NULL);
			v->wanted = (v->enabled && (stream == SND_PCM_STREAM_CAPTURE));
			v->area.addr = vector->iov_base;
			v->area.first = 0;
			v->area.step = width;
		}
		return len;
	}
}

int snd_pcm_plug_playback_channels_mask(snd_pcm_plug_t *plug,
					bitset_t *client_vmask)
{
	snd_pcm_plugin_t *plugin = snd_pcm_plug_last(plug);
	if (plugin == NULL) {
#ifndef __KERNEL__
		return snd_pcm_channels_mask(plug->slave, client_vmask);
#else
		return 0;
#endif
	} else {
		int schannels = plugin->dst_format.channels;
		bitset_t bs[bitset_size(schannels)];
		bitset_t *srcmask;
		bitset_t *dstmask = bs;
		int err;
		bitset_one(dstmask, schannels);
#ifndef __KERNEL__
		err = snd_pcm_channels_mask(plug->slave, dstmask);
		if (err < 0)
			return err;
#endif
		if (plugin == NULL) {
			bitset_and(client_vmask, dstmask, schannels);
			return 0;
		}
		while (1) {
			err = plugin->src_channels_mask(plugin, dstmask, &srcmask);
			if (err < 0)
				return err;
			dstmask = srcmask;
			if (plugin->prev == NULL)
				break;
			plugin = plugin->prev;
		}
		bitset_and(client_vmask, dstmask, plugin->src_format.channels);
		return 0;
	}
}

int snd_pcm_plug_capture_channels_mask(snd_pcm_plug_t *plug,
				       bitset_t *client_vmask)
{
	snd_pcm_plugin_t *plugin = snd_pcm_plug_first(plug);
	if (plugin == NULL) {
#ifndef __KERNEL__
		return snd_pcm_channels_mask(plug->slave, client_vmask);
#else
		return 0;
#endif
	} else {
		int schannels = plugin->src_format.channels;
		bitset_t bs[bitset_size(schannels)];
		bitset_t *srcmask = bs;
		bitset_t *dstmask;
		int err;
		bitset_one(srcmask, schannels);
#ifndef __KERNEL__
		err = snd_pcm_channels_mask(plug->slave, srcmask);
		if (err < 0)
			return err;
#endif
		while (1) {
			err = plugin->dst_channels_mask(plugin, srcmask, &dstmask);
			if (err < 0)
				return err;
			srcmask = dstmask;
			if (plugin->next == NULL)
				break;
			plugin = plugin->next;
		}
		bitset_and(client_vmask, srcmask, plugin->dst_format.channels);
		return 0;
	}
}

static int snd_pcm_plug_playback_disable_useless_channels(snd_pcm_plug_t *plug,
							  snd_pcm_plugin_channel_t *src_channels)
{
	snd_pcm_plugin_t *plugin = snd_pcm_plug_first(plug);
	unsigned int nchannels = plugin->src_format.channels;
	bitset_t bs[bitset_size(nchannels)];
	bitset_t *srcmask = bs;
	int err;
	unsigned int channel;
	for (channel = 0; channel < nchannels; channel++) {
		if (src_channels[channel].enabled)
			bitset_set(srcmask, channel);
		else
			bitset_reset(srcmask, channel);
	}
	err = snd_pcm_plug_playback_channels_mask(plug, srcmask);
	if (err < 0)
		return err;
	for (channel = 0; channel < nchannels; channel++) {
		if (!bitset_get(srcmask, channel))
			src_channels[channel].enabled = 0;
	}
	return 0;
}

static int snd_pcm_plug_capture_disable_useless_channels(snd_pcm_plug_t *plug,
							 snd_pcm_plugin_channel_t *src_channels,
							 snd_pcm_plugin_channel_t *client_channels)
{
	snd_pcm_plugin_t *plugin = snd_pcm_plug_last(plug);
	unsigned int nchannels = plugin->dst_format.channels;
	bitset_t bs[bitset_size(nchannels)];
	bitset_t *dstmask = bs;
	bitset_t *srcmask;
	int err;
	unsigned int channel;
	for (channel = 0; channel < nchannels; channel++) {
		if (client_channels[channel].enabled)
			bitset_set(dstmask, channel);
		else
			bitset_reset(dstmask, channel);
	}
	while (plugin) {
		err = plugin->src_channels_mask(plugin, dstmask, &srcmask);
		if (err < 0)
			return err;
		dstmask = srcmask;
		plugin = plugin->prev;
	}
#ifndef __KERNEL__
	err = snd_pcm_channels_mask(plug->slave, dstmask);
	if (err < 0)
		return err;
#endif
	plugin = snd_pcm_plug_first(plug);
	nchannels = plugin->src_format.channels;
	for (channel = 0; channel < nchannels; channel++) {
		if (!bitset_get(dstmask, channel))
			src_channels[channel].enabled = 0;
	}
	return 0;
}

ssize_t snd_pcm_plug_write_transfer(snd_pcm_plug_t *plug, snd_pcm_plugin_channel_t *src_channels, size_t size)
{
	snd_pcm_plugin_t *plugin, *next;
	snd_pcm_plugin_channel_t *dst_channels;
	int err;
	ssize_t frames = size;

	if ((err = snd_pcm_plug_playback_disable_useless_channels(plug, src_channels)) < 0)
		return err;
	
	plugin = snd_pcm_plug_first(plug);
	while (plugin && frames > 0) {
		if ((next = plugin->next) != NULL) {
			ssize_t frames1 = frames;
			if (plugin->dst_frames)
				frames1 = plugin->dst_frames(plugin, frames);
			if ((err = next->client_channels(next, frames1, &dst_channels)) < 0) {
				return err;
			}
			if (err != frames1) {
				frames = err;
				if (plugin->src_frames)
					frames = plugin->src_frames(plugin, frames1);
			}
		} else
			dst_channels = 0;
		pdprintf("write plugin: %s, %i\n", plugin->name, frames);
		if ((frames = plugin->transfer(plugin, src_channels, dst_channels, frames)) < 0)
			return frames;
		src_channels = dst_channels;
		plugin = next;
	}
	return snd_pcm_plug_client_size(plug, frames);
}

ssize_t snd_pcm_plug_read_transfer(snd_pcm_plug_t *plug, snd_pcm_plugin_channel_t *dst_channels_final, size_t size)
{
	snd_pcm_plugin_t *plugin, *next;
	snd_pcm_plugin_channel_t *src_channels, *dst_channels;
	ssize_t frames = size;
	int err;

	frames = snd_pcm_plug_slave_size(plug, frames);
	if (frames < 0)
		return frames;

	src_channels = 0;
	plugin = snd_pcm_plug_first(plug);
	while (plugin && frames > 0) {
		if ((next = plugin->next) != NULL) {
			if ((err = plugin->client_channels(plugin, frames, &dst_channels)) < 0) {
				return err;
			}
			frames = err;
			if (!plugin->prev) {
				if ((err = snd_pcm_plug_capture_disable_useless_channels(plug, dst_channels, dst_channels_final) < 0))
					return err;
			}
		} else {
			dst_channels = dst_channels_final;
		}
		pdprintf("read plugin: %s, %i\n", plugin->name, frames);
		if ((frames = plugin->transfer(plugin, src_channels, dst_channels, frames)) < 0)
			return frames;
		plugin = next;
		src_channels = dst_channels;
	}
	return frames;
}

int snd_pcm_area_silence(const snd_pcm_channel_area_t *dst_area, size_t dst_offset,
			 size_t samples, int format)
{
	/* FIXME: sub byte resolution and odd dst_offset */
	char *dst;
	unsigned int dst_step;
	int width;
	u_int64_t silence;
	if (!dst_area->addr)
		return 0;
	dst = dst_area->addr + (dst_area->first + dst_area->step * dst_offset) / 8;
	width = snd_pcm_format_physical_width(format);
	silence = snd_pcm_format_silence_64(format);
	if (dst_area->step == (unsigned int) width) {
		size_t dwords = samples * width / 64;
		samples -= dwords * 64 / width;
		while (dwords-- > 0)
			*((u_int64_t*)dst)++ = silence;
		if (samples == 0)
			return 0;
	}
	dst_step = dst_area->step / 8;
	switch (width) {
	case 4: {
		u_int8_t s0 = silence & 0xf0;
		u_int8_t s1 = silence & 0x0f;
		int dstbit = dst_area->first % 8;
		int dstbit_step = dst_area->step % 8;
		while (samples-- > 0) {
			if (dstbit) {
				*dst &= 0xf0;
				*dst |= s1;
			} else {
				*dst &= 0x0f;
				*dst |= s0;
			}
			dst += dst_step;
			dstbit += dstbit_step;
			if (dstbit == 8) {
				dst++;
				dstbit = 0;
			}
		}
		break;
	}
	case 8: {
		u_int8_t sil = silence;
		while (samples-- > 0) {
			*dst = sil;
			dst += dst_step;
		}
		break;
	}
	case 16: {
		u_int16_t sil = silence;
		while (samples-- > 0) {
			*(u_int16_t*)dst = sil;
			dst += dst_step;
		}
		break;
	}
	case 32: {
		u_int32_t sil = silence;
		while (samples-- > 0) {
			*(u_int32_t*)dst = sil;
			dst += dst_step;
		}
		break;
	}
	case 64: {
		while (samples-- > 0) {
			*(u_int64_t*)dst = silence;
			dst += dst_step;
		}
		break;
	}
	default:
		assert(0);
	}
	return 0;
}

int snd_pcm_areas_silence(const snd_pcm_channel_area_t *dst_areas, size_t dst_offset,
			  size_t vcount, size_t frames, int format)
{
	int width = snd_pcm_format_physical_width(format);
	while (vcount > 0) {
		void *addr = dst_areas->addr;
		unsigned int step = dst_areas->step;
		const snd_pcm_channel_area_t *begin = dst_areas;
		int vc = vcount;
		unsigned int v = 0;
		int err;
		while (1) {
			vc--;
			v++;
			dst_areas++;
			if (vc == 0 ||
			    dst_areas->addr != addr ||
			    dst_areas->step != step ||
			    dst_areas->first != dst_areas[-1].first + width)
				break;
		}
		if (v > 1 && v * width == step) {
			/* Collapse the areas */
			snd_pcm_channel_area_t d;
			d.addr = begin->addr;
			d.first = begin->first;
			d.step = width;
			err = snd_pcm_area_silence(&d, dst_offset * v, frames * v, format);
			vcount -= v;
		} else {
			err = snd_pcm_area_silence(begin, dst_offset, frames, format);
			dst_areas = begin + 1;
			vcount--;
		}
		if (err < 0)
			return err;
	}
	return 0;
}


int snd_pcm_area_copy(const snd_pcm_channel_area_t *src_area, size_t src_offset,
		      const snd_pcm_channel_area_t *dst_area, size_t dst_offset,
		      size_t samples, int format)
{
	/* FIXME: sub byte resolution and odd dst_offset */
	char *src, *dst;
	int width;
	int src_step, dst_step;
	src = src_area->addr + (src_area->first + src_area->step * src_offset) / 8;
	if (!src_area->addr)
		return snd_pcm_area_silence(dst_area, dst_offset, samples, format);
	dst = dst_area->addr + (dst_area->first + dst_area->step * dst_offset) / 8;
	if (!dst_area->addr)
		return 0;
	width = snd_pcm_format_physical_width(format);
	if (src_area->step == (unsigned int) width &&
	    dst_area->step == (unsigned int) width) {
		size_t bytes = samples * width / 8;
		samples -= bytes * 8 / width;
		memcpy(dst, src, bytes);
		if (samples == 0)
			return 0;
	}
	src_step = src_area->step / 8;
	dst_step = dst_area->step / 8;
	switch (width) {
	case 4: {
		int srcbit = src_area->first % 8;
		int srcbit_step = src_area->step % 8;
		int dstbit = dst_area->first % 8;
		int dstbit_step = dst_area->step % 8;
		while (samples-- > 0) {
			unsigned char srcval;
			if (srcbit)
				srcval = *src & 0x0f;
			else
				srcval = *src & 0xf0;
			if (dstbit)
				*dst &= 0xf0;
			else
				*dst &= 0x0f;
			*dst |= srcval;
			src += src_step;
			srcbit += srcbit_step;
			if (srcbit == 8) {
				src++;
				srcbit = 0;
			}
			dst += dst_step;
			dstbit += dstbit_step;
			if (dstbit == 8) {
				dst++;
				dstbit = 0;
			}
		}
		break;
	}
	case 8: {
		while (samples-- > 0) {
			*dst = *src;
			src += src_step;
			dst += dst_step;
		}
		break;
	}
	case 16: {
		while (samples-- > 0) {
			*(u_int16_t*)dst = *(u_int16_t*)src;
			src += src_step;
			dst += dst_step;
		}
		break;
	}
	case 32: {
		while (samples-- > 0) {
			*(u_int32_t*)dst = *(u_int32_t*)src;
			src += src_step;
			dst += dst_step;
		}
		break;
	}
	case 64: {
		while (samples-- > 0) {
			*(u_int64_t*)dst = *(u_int64_t*)src;
			src += src_step;
			dst += dst_step;
		}
		break;
	}
	default:
		assert(0);
	}
	return 0;
}

int snd_pcm_areas_copy(const snd_pcm_channel_area_t *src_areas, size_t src_offset,
		       const snd_pcm_channel_area_t *dst_areas, size_t dst_offset,
		       size_t vcount, size_t frames, int format)
{
	int width = snd_pcm_format_physical_width(format);
	while (vcount > 0) {
		unsigned int step = src_areas->step;
		void *src_addr = src_areas->addr;
		const snd_pcm_channel_area_t *src_start = src_areas;
		void *dst_addr = dst_areas->addr;
		const snd_pcm_channel_area_t *dst_start = dst_areas;
		int vc = vcount;
		unsigned int v = 0;
		while (dst_areas->step == step) {
			vc--;
			v++;
			src_areas++;
			dst_areas++;
			if (vc == 0 ||
			    src_areas->step != step ||
			    src_areas->addr != src_addr ||
			    dst_areas->addr != dst_addr ||
			    src_areas->first != src_areas[-1].first + width ||
			    dst_areas->first != dst_areas[-1].first + width)
				break;
		}
		if (v > 1 && v * width == step) {
			/* Collapse the areas */
			snd_pcm_channel_area_t s, d;
			s.addr = src_start->addr;
			s.first = src_start->first;
			s.step = width;
			d.addr = dst_start->addr;
			d.first = dst_start->first;
			d.step = width;
			snd_pcm_area_copy(&s, src_offset * v, &d, dst_offset * v, frames * v, format);
			vcount -= v;
		} else {
			snd_pcm_area_copy(src_start, src_offset, dst_start, dst_offset, frames, format);
			src_areas = src_start + 1;
			dst_areas = dst_start + 1;
			vcount--;
		}
	}
	return 0;
}