Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 *  Linear conversion Plug-In

 *  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., 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"

static snd_pcm_sframes_t copy_transfer(struct snd_pcm_plugin *plugin,

                             const struct snd_pcm_plugin_channel *src_channels,

                             struct snd_pcm_plugin_channel *dst_channels,

                             snd_pcm_uframes_t frames)

{

        unsigned int channel;

        unsigned int nchannels;

        snd_assert(plugin != NULL && src_channels != NULL && dst_channels != NULL, return -ENXIO);

        if (frames == 0)

                return 0;

        nchannels = plugin->src_format.channels;

        for (channel = 0; channel < nchannels; channel++) {

                snd_assert(src_channels->area.first % 8 == 0 &&

                           src_channels->area.step % 8 == 0,

                           return -ENXIO);

                snd_assert(dst_channels->area.first % 8 == 0 &&

                           dst_channels->area.step % 8 == 0,

                           return -ENXIO);

                if (!src_channels->enabled) {

                        if (dst_channels->wanted)

                                snd_pcm_area_silence(&dst_channels->area, 0, frames, plugin->dst_format.format);

                        dst_channels->enabled = 0;

                        continue;

                }

                dst_channels->enabled = 1;

                snd_pcm_area_copy(&src_channels->area, 0, &dst_channels->area, 0, frames, plugin->src_format.format);

                src_channels++;

                dst_channels++;

        }

        return frames;

}

int snd_pcm_plugin_build_copy(struct snd_pcm_substream *plug,

                              struct snd_pcm_plugin_format *src_format,

                              struct snd_pcm_plugin_format *dst_format,

                              struct snd_pcm_plugin **r_plugin)

{

        int err;

        struct snd_pcm_plugin *plugin;

        int width;

        snd_assert(r_plugin != NULL, return -ENXIO);

        *r_plugin = NULL;

        snd_assert(src_format->format == dst_format->format, return -ENXIO);

        snd_assert(src_format->rate == dst_format->rate, return -ENXIO);

        snd_assert(src_format->channels == dst_format->channels, return -ENXIO);

        width = snd_pcm_format_physical_width(src_format->format);

        snd_assert(width > 0, return -ENXIO);

        err = snd_pcm_plugin_build(plug, "copy", src_format, dst_format,

                                   0, &plugin);

        if (err < 0)

                return err;

        plugin->transfer = copy_transfer;

        *r_plugin = plugin;

        return 0;

}