/* *  Rate conversion Plug-In *  Copyright (c) 1999 by Jaroslav Kysela <perex@suse.cz> * * *   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA * */  #include <sound/driver.h>#include <linux/time.h>#include <sound/core.h>#include <sound/pcm.h>#include "pcm_plugin.h"#define SHIFT	11#define BITS	(1<<SHIFT)#define R_MASK	(BITS-1)/* *  Basic rate conversion plugin */typedef struct {	signed short last_S1;	signed short last_S2;} rate_channel_t; typedef void (*rate_f)(snd_pcm_plugin_t *plugin,		       const snd_pcm_plugin_channel_t *src_channels,		       snd_pcm_plugin_channel_t *dst_channels,		       int src_frames, int dst_frames);typedef struct rate_private_data {	unsigned int pitch;	unsigned int pos;	rate_f func;	int get, put;	snd_pcm_sframes_t old_src_frames, old_dst_frames;	rate_channel_t channels[0];} rate_t;static void rate_init(snd_pcm_plugin_t *plugin){	unsigned int channel;	rate_t *data = (rate_t *)plugin->extra_data;	data->pos = 0;	for (channel = 0; channel < plugin->src_format.channels; channel++) {		data->channels[channel].last_S1 = 0;		data->channels[channel].last_S2 = 0;	}}static void resample_expand(snd_pcm_plugin_t *plugin,			    const snd_pcm_plugin_channel_t *src_channels,			    snd_pcm_plugin_channel_t *dst_channels,			    int src_frames, int dst_frames){	unsigned int pos = 0;	signed int val;	signed short S1, S2;	char *src, *dst;	unsigned int channel;	int src_step, dst_step;	int src_frames1, dst_frames1;	rate_t *data = (rate_t *)plugin->extra_data;	rate_channel_t *rchannels = data->channels;#define GET_S16_LABELS#define PUT_S16_LABELS#include "plugin_ops.h"#undef GET_S16_LABELS#undef PUT_S16_LABELS	void *get = get_s16_labels[data->get];	void *put = put_s16_labels[data->put];	signed short sample = 0;		for (channel = 0; channel < plugin->src_format.channels; channel++) {		pos = data->pos;		S1 = rchannels->last_S1;		S2 = rchannels->last_S2;		if (!src_channels[channel].enabled) {			if (dst_channels[channel].wanted)				snd_pcm_area_silence(&dst_channels[channel].area, 0, dst_frames, plugin->dst_format.format);			dst_channels[channel].enabled = 0;			continue;		}		dst_channels[channel].enabled = 1;		src = (char *)src_channels[channel].area.addr + src_channels[channel].area.first / 8;		dst = (char *)dst_channels[channel].area.addr + dst_channels[channel].area.first / 8;		src_step = src_channels[channel].area.step / 8;		dst_step = dst_channels[channel].area.step / 8;		src_frames1 = src_frames;		dst_frames1 = dst_frames;		while (dst_frames1-- > 0) {			if (pos & ~R_MASK) {				pos &= R_MASK;				S1 = S2;				if (src_frames1-- > 0) {					goto *get;#define GET_S16_END after_get#include "plugin_ops.h"#undef GET_S16_END				after_get:					S2 = sample;					src += src_step;				}			}			val = S1 + ((S2 - S1) * (signed int)pos) / BITS;			if (val < -32768)				val = -32768;			else if (val > 32767)				val = 32767;			sample = val;			goto *put;#define PUT_S16_END after_put#include "plugin_ops.h"#undef PUT_S16_END		after_put:			dst += dst_step;			pos += data->pitch;		}		rchannels->last_S1 = S1;		rchannels->last_S2 = S2;		rchannels++;	}	data->pos = pos;}static void resample_shrink(snd_pcm_plugin_t *plugin,			    const snd_pcm_plugin_channel_t *src_channels,			    snd_pcm_plugin_channel_t *dst_channels,			    int src_frames, int dst_frames){	unsigned int pos = 0;	signed int val;	signed short S1, S2;	char *src, *dst;	unsigned int channel;	int src_step, dst_step;	int src_frames1, dst_frames1;	rate_t *data = (rate_t *)plugin->extra_data;	rate_channel_t *rchannels = data->channels;	#define GET_S16_LABELS#define PUT_S16_LABELS#include "plugin_ops.h"#undef GET_S16_LABELS#undef PUT_S16_LABELS	void *get = get_s16_labels[data->get];	void *put = put_s16_labels[data->put];	signed short sample = 0;	for (channel = 0; channel < plugin->src_format.channels; ++channel) {		pos = data->pos;		S1 = rchannels->last_S1;		S2 = rchannels->last_S2;		if (!src_channels[channel].enabled) {			if (dst_channels[channel].wanted)				snd_pcm_area_silence(&dst_channels[channel].area, 0, dst_frames, plugin->dst_format.format);			dst_channels[channel].enabled = 0;			continue;		}		dst_channels[channel].enabled = 1;		src = (char *)src_channels[channel].area.addr + src_channels[channel].area.first / 8;		dst = (char *)dst_channels[channel].area.addr + dst_channels[channel].area.first / 8;		src_step = src_channels[channel].area.step / 8;		dst_step = dst_channels[channel].area.step / 8;		src_frames1 = src_frames;		dst_frames1 = dst_frames;		while (dst_frames1 > 0) {			S1 = S2;			if (src_frames1-- > 0) {				goto *get;#define GET_S16_END after_get#include "plugin_ops.h"#undef GET_S16_END			after_get:				S2 = sample;				src += src_step;			}			if (pos & ~R_MASK) {				pos &= R_MASK;				val = S1 + ((S2 - S1) * (signed int)pos) / BITS;				if (val < -32768)					val = -32768;				else if (val > 32767)					val = 32767;				sample = val;				goto *put;#define PUT_S16_END after_put#include "plugin_ops.h"#undef PUT_S16_END			after_put:				dst += dst_step;				dst_frames1--;			}			pos += data->pitch;		}		rchannels->last_S1 = S1;		rchannels->last_S2 = S2;		rchannels++;	}	data->pos = pos;}static snd_pcm_sframes_t rate_src_frames(snd_pcm_plugin_t *plugin, snd_pcm_uframes_t frames){	rate_t *data;	snd_pcm_sframes_t res;	snd_assert(plugin != NULL, return -ENXIO);	if (frames == 0)		return 0;	data = (rate_t *)plugin->extra_data;	if (plugin->src_format.rate < plugin->dst_format.rate) {		res = (((frames * data->pitch) + (BITS/2)) >> SHIFT);	} else {		res = (((frames << SHIFT) + (data->pitch / 2)) / data->pitch);			}	if (data->old_src_frames > 0) {		snd_pcm_sframes_t frames1 = frames, res1 = data->old_dst_frames;		while (data->old_src_frames < frames1) {			frames1 >>= 1;			res1 <<= 1;		}		while (data->old_src_frames > frames1) {			frames1 <<= 1;			res1 >>= 1;		}		if (data->old_src_frames == frames1)			return res1;	}	data->old_src_frames = frames;	data->old_dst_frames = res;	return res;}static snd_pcm_sframes_t rate_dst_frames(snd_pcm_plugin_t *plugin, snd_pcm_uframes_t frames){	rate_t *data;	snd_pcm_sframes_t res;	snd_assert(plugin != NULL, return -ENXIO);	if (frames == 0)		return 0;	data = (rate_t *)plugin->extra_data;	if (plugin->src_format.rate < plugin->dst_format.rate) {		res = (((frames << SHIFT) + (data->pitch / 2)) / data->pitch);	} else {		res = (((frames * data->pitch) + (BITS/2)) >> SHIFT);	}	if (data->old_dst_frames > 0) {		snd_pcm_sframes_t frames1 = frames, res1 = data->old_src_frames;		while (data->old_dst_frames < frames1) {			frames1 >>= 1;			res1 <<= 1;		}		while (data->old_dst_frames > frames1) {			frames1 <<= 1;			res1 >>= 1;		}		if (data->old_dst_frames == frames1)			return res1;	}	data->old_dst_frames = frames;	data->old_src_frames = res;	return res;}static snd_pcm_sframes_t rate_transfer(snd_pcm_plugin_t *plugin,			     const snd_pcm_plugin_channel_t *src_channels,			     snd_pcm_plugin_channel_t *dst_channels,			     snd_pcm_uframes_t frames){	snd_pcm_uframes_t dst_frames;	rate_t *data;	snd_assert(plugin != NULL && src_channels != NULL && dst_channels != NULL, return -ENXIO);	if (frames == 0)		return 0;#ifdef CONFIG_SND_DEBUG	{		unsigned int channel;		for (channel = 0; channel < plugin->src_format.channels; channel++) {			snd_assert(src_channels[channel].area.first % 8 == 0 &&				   src_channels[channel].area.step % 8 == 0,				   return -ENXIO);			snd_assert(dst_channels[channel].area.first % 8 == 0 &&				   dst_channels[channel].area.step % 8 == 0,				   return -ENXIO);		}	}#endif	dst_frames = rate_dst_frames(plugin, frames);	if (dst_frames > dst_channels[0].frames)		dst_frames = dst_channels[0].frames;	data = (rate_t *)plugin->extra_data;	data->func(plugin, src_channels, dst_channels, frames, dst_frames);	return dst_frames;}static int rate_action(snd_pcm_plugin_t *plugin,		       snd_pcm_plugin_action_t action,		       unsigned long udata ATTRIBUTE_UNUSED){	snd_assert(plugin != NULL, return -ENXIO);	switch (action) {	case INIT:	case PREPARE:		rate_init(plugin);		break;	default:		break;	}	return 0;	/* silenty ignore other actions */}int snd_pcm_plugin_build_rate(snd_pcm_plug_t *plug,			      snd_pcm_plugin_format_t *src_format,			      snd_pcm_plugin_format_t *dst_format,			      snd_pcm_plugin_t **r_plugin){	int err;	rate_t *data;	snd_pcm_plugin_t *plugin;	snd_assert(r_plugin != NULL, return -ENXIO);	*r_plugin = NULL;	snd_assert(src_format->channels == dst_format->channels, return -ENXIO);	snd_assert(src_format->channels > 0, return -ENXIO);	snd_assert(snd_pcm_format_linear(src_format->format) != 0, return -ENXIO);	snd_assert(snd_pcm_format_linear(dst_format->format) != 0, return -ENXIO);	snd_assert(src_format->rate != dst_format->rate, return -ENXIO);	err = snd_pcm_plugin_build(plug, "rate conversion",				   src_format, dst_format,				   sizeof(rate_t) + src_format->channels * sizeof(rate_channel_t),				   &plugin);	if (err < 0)		return err;	data = (rate_t *)plugin->extra_data;	data->get = getput_index(src_format->format);	data->put = getput_index(dst_format->format);	if (src_format->rate < dst_format->rate) {		data->pitch = ((src_format->rate << SHIFT) + (dst_format->rate >> 1)) / dst_format->rate;		data->func = resample_expand;	} else {		data->pitch = ((dst_format->rate << SHIFT) + (src_format->rate >> 1)) / src_format->rate;		data->func = resample_shrink;	}	data->pos = 0;	rate_init(plugin);	data->old_src_frames = data->old_dst_frames = 0;	plugin->transfer = rate_transfer;	plugin->src_frames = rate_src_frames;	plugin->dst_frames = rate_dst_frames;	plugin->action = rate_action;	*r_plugin = plugin;	return 0;}