copy.c

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/*
 *  Linear conversion Plug-In
 *  Copyright (c) 2000 by Abramo Bagnara <[email protected]>
 *
 *
 *   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 <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;

    if (snd_BUG_ON(!plugin || !src_channels || !dst_channels))
        return -ENXIO;
    if (frames == 0)
        return 0;
    nchannels = plugin->src_format.channels;
    for (channel = 0; channel < nchannels; channel++) {
        if (snd_BUG_ON(src_channels->area.first % 8 ||
                   src_channels->area.step % 8))
            return -ENXIO;
        if (snd_BUG_ON(dst_channels->area.first % 8 ||
                   dst_channels->area.step % 8))
            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;

    if (snd_BUG_ON(!r_plugin))
        return -ENXIO;
    *r_plugin = NULL;

    if (snd_BUG_ON(src_format->format != dst_format->format))
        return -ENXIO;
    if (snd_BUG_ON(src_format->rate != dst_format->rate))
        return -ENXIO;
    if (snd_BUG_ON(src_format->channels != dst_format->channels))
        return -ENXIO;

    width = snd_pcm_format_physical_width(src_format->format);
    if (snd_BUG_ON(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;
}