1 /*
2 * Route 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 <linux/time.h>
23 #include <sound/core.h>
24 #include <sound/pcm.h>
25 #include "pcm_plugin.h"
26
27 static void zero_areas(struct snd_pcm_plugin_channel *dvp, int ndsts,
28 snd_pcm_uframes_t frames, snd_pcm_format_t format)
29 {
30 int dst = 0;
31 for (; dst < ndsts; ++dst) {
32 if (dvp->wanted)
33 snd_pcm_area_silence(&dvp->area, 0, frames, format);
34 dvp->enabled = 0;
35 dvp++;
36 }
37 }
38
39 static inline void copy_area(const struct snd_pcm_plugin_channel *src_channel,
40 struct snd_pcm_plugin_channel *dst_channel,
41 snd_pcm_uframes_t frames, snd_pcm_format_t format)
42 {
43 dst_channel->enabled = 1;
44 snd_pcm_area_copy(&src_channel->area, 0, &dst_channel->area, 0, frames, format);
45 }
46
47 static snd_pcm_sframes_t route_transfer(struct snd_pcm_plugin *plugin,
48 const struct snd_pcm_plugin_channel *src_channels,
49 struct snd_pcm_plugin_channel *dst_channels,
50 snd_pcm_uframes_t frames)
51 {
52 int nsrcs, ndsts, dst;
53 struct snd_pcm_plugin_channel *dvp;
54 snd_pcm_format_t format;
55
56 if (snd_BUG_ON(!plugin || !src_channels || !dst_channels))
57 return -ENXIO;
58 if (frames == 0)
59 return 0;
60 if (frames > dst_channels[0].frames)
61 frames = dst_channels[0].frames;
62
63 nsrcs = plugin->src_format.channels;
64 ndsts = plugin->dst_format.channels;
65
66 format = plugin->dst_format.format;
67 dvp = dst_channels;
68 if (nsrcs <= 1) {
69 /* expand to all channels */
70 for (dst = 0; dst < ndsts; ++dst) {
71 copy_area(src_channels, dvp, frames, format);
72 dvp++;
73 }
74 return frames;
75 }
76
77 for (dst = 0; dst < ndsts && dst < nsrcs; ++dst) {
78 copy_area(src_channels, dvp, frames, format);
79 dvp++;
80 src_channels++;
81 }
82 if (dst < ndsts)
83 zero_areas(dvp, ndsts - dst, frames, format);
84 return frames;
85 }
86
87 int snd_pcm_plugin_build_route(struct snd_pcm_substream *plug,
88 struct snd_pcm_plugin_format *src_format,
89 struct snd_pcm_plugin_format *dst_format,
90 struct snd_pcm_plugin **r_plugin)
91 {
92 struct snd_pcm_plugin *plugin;
93 int err;
94
95 if (snd_BUG_ON(!r_plugin))
96 return -ENXIO;
97 *r_plugin = NULL;
98 if (snd_BUG_ON(src_format->rate != dst_format->rate))
99 return -ENXIO;
100 if (snd_BUG_ON(src_format->format != dst_format->format))
101 return -ENXIO;
102
103 err = snd_pcm_plugin_build(plug, "route conversion",
104 src_format, dst_format, 0, &plugin);
105 if (err < 0)
106 return err;
107
108 plugin->transfer = route_transfer;
109 *r_plugin = plugin;
110 return 0;
111 }
112
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