1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
|
/*
* 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;
}
|
