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(dst_channel: &dvp->area, dst_offset: 0, samples: 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: &src_channel->area, src_offset: 0, dst_channel: &dst_channel->area, dst_offset: 0, samples: 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_channel: src_channels, dst_channel: dvp, frames, format); |
72 | dvp++; |
73 | } |
74 | return frames; |
75 | } |
76 | |
77 | for (dst = 0; dst < ndsts && dst < nsrcs; ++dst) { |
78 | copy_area(src_channel: src_channels, dst_channel: dvp, frames, format); |
79 | dvp++; |
80 | src_channels++; |
81 | } |
82 | if (dst < ndsts) |
83 | zero_areas(dvp, ndsts: 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(handle: plug, name: "route conversion" , |
104 | src_format, dst_format, extra: 0, ret: &plugin); |
105 | if (err < 0) |
106 | return err; |
107 | |
108 | plugin->transfer = route_transfer; |
109 | *r_plugin = plugin; |
110 | return 0; |
111 | } |
112 | |