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
27static 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
39static 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
47static 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
87int 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