Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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kernel
os
linux
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#include <linux/time.h>
24#include <sound/core.h>
25#include <sound/pcm.h>
26#include "pcm_plugin.h"
27
28static snd_pcm_sframes_t copy_transfer(snd_pcm_plugin_t *plugin,
29 const snd_pcm_plugin_channel_t *src_channels,
30 snd_pcm_plugin_channel_t *dst_channels,
31 snd_pcm_uframes_t frames)
32{
33 unsigned int channel;
34 unsigned int nchannels;
35
36 snd_assert(plugin != NULL && src_channels != NULL && dst_channels != NULL, return -ENXIO);
37 if (frames == 0)
38 return 0;
39 nchannels = plugin->src_format.channels;
40 for (channel = 0; channel < nchannels; channel++) {
41 snd_assert(src_channels->area.first % 8 == 0 &&
42 src_channels->area.step % 8 == 0,
43 return -ENXIO);
44 snd_assert(dst_channels->area.first % 8 == 0 &&
45 dst_channels->area.step % 8 == 0,
46 return -ENXIO);
47 if (!src_channels->enabled) {
48 if (dst_channels->wanted)
49 snd_pcm_area_silence(&dst_channels->area, 0, frames, plugin->dst_format.format);
50 dst_channels->enabled = 0;
51 continue;
52 }
53 dst_channels->enabled = 1;
54 snd_pcm_area_copy(&src_channels->area, 0, &dst_channels->area, 0, frames, plugin->src_format.format);
55 src_channels++;
56 dst_channels++;
57 }
58 return frames;
59}
60
61int snd_pcm_plugin_build_copy(snd_pcm_plug_t *plug,
62 snd_pcm_plugin_format_t *src_format,
63 snd_pcm_plugin_format_t *dst_format,
64 snd_pcm_plugin_t **r_plugin)
65{
66 int err;
67 snd_pcm_plugin_t *plugin;
68 int width;
69
70 snd_assert(r_plugin != NULL, return -ENXIO);
71 *r_plugin = NULL;
72
73 snd_assert(src_format->format == dst_format->format, return -ENXIO);
74 snd_assert(src_format->rate == dst_format->rate, return -ENXIO);
75 snd_assert(src_format->channels == dst_format->channels, return -ENXIO);
76
77 width = snd_pcm_format_physical_width(src_format->format);
78 snd_assert(width > 0, return -ENXIO);
79
80 err = snd_pcm_plugin_build(plug, "copy", src_format, dst_format,
81 0, &plugin);
82 if (err < 0)
83 return err;
84 plugin->transfer = copy_transfer;
85 *r_plugin = plugin;
86 return 0;
87}