1/*
2 *  Linear conversion Plug-In
3 *  Copyright (c) 2000 by Abramo Bagnara <abramo@alsa-project.org>
4 *
5 *
6 *   This library is free software; you can redistribute it and/or modify
7 *   it under the terms of the GNU Library General Public License as
8 *   published by the Free Software Foundation; either version 2 of
9 *   the License, or (at your option) any later version.
10 *
11 *   This program is distributed in the hope that it will be useful,
12 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
13 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14 *   GNU Library General Public License for more details.
15 *
16 *   You should have received a copy of the GNU Library General Public
17 *   License along with this library; if not, write to the Free Software
18 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
19 *
20 */
21
22#include <sound/driver.h>
23
24#ifdef CONFIG_SND_PCM_OSS_PLUGINS
25
26#include <linux/time.h>
27#include <sound/core.h>
28#include <sound/pcm.h>
29#include "pcm_plugin.h"
30
31static snd_pcm_sframes_t copy_transfer(struct snd_pcm_plugin *plugin,
32			     const struct snd_pcm_plugin_channel *src_channels,
33			     struct snd_pcm_plugin_channel *dst_channels,
34			     snd_pcm_uframes_t frames)
35{
36	unsigned int channel;
37	unsigned int nchannels;
38
39	snd_assert(plugin != NULL && src_channels != NULL && dst_channels != NULL, return -ENXIO);
40	if (frames == 0)
41		return 0;
42	nchannels = plugin->src_format.channels;
43	for (channel = 0; channel < nchannels; channel++) {
44		snd_assert(src_channels->area.first % 8 == 0 &&
45			   src_channels->area.step % 8 == 0,
46			   return -ENXIO);
47		snd_assert(dst_channels->area.first % 8 == 0 &&
48			   dst_channels->area.step % 8 == 0,
49			   return -ENXIO);
50		if (!src_channels->enabled) {
51			if (dst_channels->wanted)
52				snd_pcm_area_silence(&dst_channels->area, 0, frames, plugin->dst_format.format);
53			dst_channels->enabled = 0;
54			continue;
55		}
56		dst_channels->enabled = 1;
57		snd_pcm_area_copy(&src_channels->area, 0, &dst_channels->area, 0, frames, plugin->src_format.format);
58		src_channels++;
59		dst_channels++;
60	}
61	return frames;
62}
63
64int snd_pcm_plugin_build_copy(struct snd_pcm_substream *plug,
65			      struct snd_pcm_plugin_format *src_format,
66			      struct snd_pcm_plugin_format *dst_format,
67			      struct snd_pcm_plugin **r_plugin)
68{
69	int err;
70	struct snd_pcm_plugin *plugin;
71	int width;
72
73	snd_assert(r_plugin != NULL, return -ENXIO);
74	*r_plugin = NULL;
75
76	snd_assert(src_format->format == dst_format->format, return -ENXIO);
77	snd_assert(src_format->rate == dst_format->rate, return -ENXIO);
78	snd_assert(src_format->channels == dst_format->channels, return -ENXIO);
79
80	width = snd_pcm_format_physical_width(src_format->format);
81	snd_assert(width > 0, return -ENXIO);
82
83	err = snd_pcm_plugin_build(plug, "copy", src_format, dst_format,
84				   0, &plugin);
85	if (err < 0)
86		return err;
87	plugin->transfer = copy_transfer;
88	*r_plugin = plugin;
89	return 0;
90}
91
92#endif
93