Merge branch 'master' of /home/aia21/ntfs-2.6/
[linux-2.6] / sound / core / oss / copy.c
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
24 #ifdef CONFIG_SND_PCM_OSS_PLUGINS
25
26 #include <linux/time.h>
27 #include <sound/core.h>
28 #include <sound/pcm.h>
29 #include "pcm_plugin.h"
30
31 static snd_pcm_sframes_t copy_transfer(struct snd_pcm_plugin *plugin,
32                              const struct snd_pcm_plugin_channel *src_channels,
33                              struct snd_pcm_plugin_channel *dst_channels,
34                              snd_pcm_uframes_t frames)
35 {
36         unsigned int channel;
37         unsigned int nchannels;
38
39         snd_assert(plugin != NULL && src_channels != NULL && dst_channels != NULL, return -ENXIO);
40         if (frames == 0)
41                 return 0;
42         nchannels = plugin->src_format.channels;
43         for (channel = 0; channel < nchannels; channel++) {
44                 snd_assert(src_channels->area.first % 8 == 0 &&
45                            src_channels->area.step % 8 == 0,
46                            return -ENXIO);
47                 snd_assert(dst_channels->area.first % 8 == 0 &&
48                            dst_channels->area.step % 8 == 0,
49                            return -ENXIO);
50                 if (!src_channels->enabled) {
51                         if (dst_channels->wanted)
52                                 snd_pcm_area_silence(&dst_channels->area, 0, frames, plugin->dst_format.format);
53                         dst_channels->enabled = 0;
54                         continue;
55                 }
56                 dst_channels->enabled = 1;
57                 snd_pcm_area_copy(&src_channels->area, 0, &dst_channels->area, 0, frames, plugin->src_format.format);
58                 src_channels++;
59                 dst_channels++;
60         }
61         return frames;
62 }
63
64 int snd_pcm_plugin_build_copy(struct snd_pcm_substream *plug,
65                               struct snd_pcm_plugin_format *src_format,
66                               struct snd_pcm_plugin_format *dst_format,
67                               struct snd_pcm_plugin **r_plugin)
68 {
69         int err;
70         struct snd_pcm_plugin *plugin;
71         int width;
72
73         snd_assert(r_plugin != NULL, return -ENXIO);
74         *r_plugin = NULL;
75
76         snd_assert(src_format->format == dst_format->format, return -ENXIO);
77         snd_assert(src_format->rate == dst_format->rate, return -ENXIO);
78         snd_assert(src_format->channels == dst_format->channels, return -ENXIO);
79
80         width = snd_pcm_format_physical_width(src_format->format);
81         snd_assert(width > 0, return -ENXIO);
82
83         err = snd_pcm_plugin_build(plug, "copy", src_format, dst_format,
84                                    0, &plugin);
85         if (err < 0)
86                 return err;
87         plugin->transfer = copy_transfer;
88         *r_plugin = plugin;
89         return 0;
90 }
91
92 #endif