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 <linux/time.h>
23#include <sound/core.h>
24#include <sound/pcm.h>
25#include "pcm_plugin.h"
26
27static snd_pcm_sframes_t copy_transfer(struct snd_pcm_plugin *plugin,
28			     const struct snd_pcm_plugin_channel *src_channels,
29			     struct snd_pcm_plugin_channel *dst_channels,
30			     snd_pcm_uframes_t frames)
31{
32	unsigned int channel;
33	unsigned int nchannels;
34
35	if (snd_BUG_ON(!plugin || !src_channels || !dst_channels))
36		return -ENXIO;
37	if (frames == 0)
38		return 0;
39	nchannels = plugin->src_format.channels;
40	for (channel = 0; channel < nchannels; channel++) {
41		if (snd_BUG_ON(src_channels->area.first % 8 ||
42			       src_channels->area.step % 8))
43			return -ENXIO;
44		if (snd_BUG_ON(dst_channels->area.first % 8 ||
45			       dst_channels->area.step % 8))
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(struct snd_pcm_substream *plug,
62			      struct snd_pcm_plugin_format *src_format,
63			      struct snd_pcm_plugin_format *dst_format,
64			      struct snd_pcm_plugin **r_plugin)
65{
66	int err;
67	struct snd_pcm_plugin *plugin;
68	int width;
69
70	if (snd_BUG_ON(!r_plugin))
71		return -ENXIO;
72	*r_plugin = NULL;
73
74	if (snd_BUG_ON(src_format->format != dst_format->format))
75		return -ENXIO;
76	if (snd_BUG_ON(src_format->rate != dst_format->rate))
77		return -ENXIO;
78	if (snd_BUG_ON(src_format->channels != dst_format->channels))
79		return -ENXIO;
80
81	width = snd_pcm_format_physical_width(src_format->format);
82	if (snd_BUG_ON(width <= 0))
83		return -ENXIO;
84
85	err = snd_pcm_plugin_build(plug, "copy", src_format, dst_format,
86				   0, &plugin);
87	if (err < 0)
88		return err;
89	plugin->transfer = copy_transfer;
90	*r_plugin = plugin;
91	return 0;
92}
93