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
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
|
/*
* Route 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 <linux/time.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include "pcm_plugin.h"
static void zero_areas(struct snd_pcm_plugin_channel *dvp, int ndsts,
snd_pcm_uframes_t frames, int format)
{
int dst = 0;
for (; dst < ndsts; ++dst) {
if (dvp->wanted)
snd_pcm_area_silence(&dvp->area, 0, frames, format);
dvp->enabled = 0;
dvp++;
}
}
static inline void copy_area(const struct snd_pcm_plugin_channel *src_channel,
struct snd_pcm_plugin_channel *dst_channel,
snd_pcm_uframes_t frames, int format)
{
dst_channel->enabled = 1;
snd_pcm_area_copy(&src_channel->area, 0, &dst_channel->area, 0, frames, format);
}
static snd_pcm_sframes_t route_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)
{
int nsrcs, ndsts, dst;
struct snd_pcm_plugin_channel *dvp;
int format;
if (snd_BUG_ON(!plugin || !src_channels || !dst_channels))
return -ENXIO;
if (frames == 0)
return 0;
nsrcs = plugin->src_format.channels;
ndsts = plugin->dst_format.channels;
format = plugin->dst_format.format;
dvp = dst_channels;
if (nsrcs <= 1) {
/* expand to all channels */
for (dst = 0; dst < ndsts; ++dst) {
copy_area(src_channels, dvp, frames, format);
dvp++;
}
return frames;
}
for (dst = 0; dst < ndsts && dst < nsrcs; ++dst) {
copy_area(src_channels, dvp, frames, format);
dvp++;
src_channels++;
}
if (dst < ndsts)
zero_areas(dvp, ndsts - dst, frames, format);
return frames;
}
int snd_pcm_plugin_build_route(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)
{
struct snd_pcm_plugin *plugin;
int err;
if (snd_BUG_ON(!r_plugin))
return -ENXIO;
*r_plugin = NULL;
if (snd_BUG_ON(src_format->rate != dst_format->rate))
return -ENXIO;
if (snd_BUG_ON(src_format->format != dst_format->format))
return -ENXIO;
err = snd_pcm_plugin_build(plug, "route conversion",
src_format, dst_format, 0, &plugin);
if (err < 0)
return err;
plugin->transfer = route_transfer;
*r_plugin = plugin;
return 0;
}
|
