1/*
2 *  Linear conversion Plug-In
3 *  Copyright (c) 1999 by Jaroslav Kysela <perex@suse.cz>,
4 *			  Abramo Bagnara <abramo@alsa-project.org>
5 *
6 *
7 *   This library is free software; you can redistribute it and/or modify
8 *   it under the terms of the GNU Library General Public License as
9 *   published by the Free Software Foundation; either version 2 of
10 *   the License, or (at your option) any later version.
11 *
12 *   This program is distributed in the hope that it will be useful,
13 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
14 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15 *   GNU Library General Public License for more details.
16 *
17 *   You should have received a copy of the GNU Library General Public
18 *   License along with this library; if not, write to the Free Software
19 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
20 *
21 */
22
23#include <sound/driver.h>
24
25#ifdef CONFIG_SND_PCM_OSS_PLUGINS
26
27#include <linux/time.h>
28#include <sound/core.h>
29#include <sound/pcm.h>
30#include "pcm_plugin.h"
31
32/*
33 *  Basic linear conversion plugin
34 */
35
36struct linear_priv {
37	int conv;
38};
39
40static void convert(struct snd_pcm_plugin *plugin,
41		    const struct snd_pcm_plugin_channel *src_channels,
42		    struct snd_pcm_plugin_channel *dst_channels,
43		    snd_pcm_uframes_t frames)
44{
45#define CONV_LABELS
46#include "plugin_ops.h"
47#undef CONV_LABELS
48	struct linear_priv *data = (struct linear_priv *)plugin->extra_data;
49	void *conv = conv_labels[data->conv];
50	int channel;
51	int nchannels = plugin->src_format.channels;
52	for (channel = 0; channel < nchannels; ++channel) {
53		char *src;
54		char *dst;
55		int src_step, dst_step;
56		snd_pcm_uframes_t frames1;
57		if (!src_channels[channel].enabled) {
58			if (dst_channels[channel].wanted)
59				snd_pcm_area_silence(&dst_channels[channel].area, 0, frames, plugin->dst_format.format);
60			dst_channels[channel].enabled = 0;
61			continue;
62		}
63		dst_channels[channel].enabled = 1;
64		src = src_channels[channel].area.addr + src_channels[channel].area.first / 8;
65		dst = dst_channels[channel].area.addr + dst_channels[channel].area.first / 8;
66		src_step = src_channels[channel].area.step / 8;
67		dst_step = dst_channels[channel].area.step / 8;
68		frames1 = frames;
69		while (frames1-- > 0) {
70			goto *conv;
71#define CONV_END after
72#include "plugin_ops.h"
73#undef CONV_END
74		after:
75			src += src_step;
76			dst += dst_step;
77		}
78	}
79}
80
81static snd_pcm_sframes_t linear_transfer(struct snd_pcm_plugin *plugin,
82			       const struct snd_pcm_plugin_channel *src_channels,
83			       struct snd_pcm_plugin_channel *dst_channels,
84			       snd_pcm_uframes_t frames)
85{
86	struct linear_priv *data;
87
88	snd_assert(plugin != NULL && src_channels != NULL && dst_channels != NULL, return -ENXIO);
89	data = (struct linear_priv *)plugin->extra_data;
90	if (frames == 0)
91		return 0;
92#ifdef CONFIG_SND_DEBUG
93	{
94		unsigned int channel;
95		for (channel = 0; channel < plugin->src_format.channels; channel++) {
96			snd_assert(src_channels[channel].area.first % 8 == 0 &&
97				   src_channels[channel].area.step % 8 == 0,
98				   return -ENXIO);
99			snd_assert(dst_channels[channel].area.first % 8 == 0 &&
100				   dst_channels[channel].area.step % 8 == 0,
101				   return -ENXIO);
102		}
103	}
104#endif
105	convert(plugin, src_channels, dst_channels, frames);
106	return frames;
107}
108
109static int conv_index(int src_format, int dst_format)
110{
111	int src_endian, dst_endian, sign, src_width, dst_width;
112
113	sign = (snd_pcm_format_signed(src_format) !=
114		snd_pcm_format_signed(dst_format));
115#ifdef SNDRV_LITTLE_ENDIAN
116	src_endian = snd_pcm_format_big_endian(src_format);
117	dst_endian = snd_pcm_format_big_endian(dst_format);
118#else
119	src_endian = snd_pcm_format_little_endian(src_format);
120	dst_endian = snd_pcm_format_little_endian(dst_format);
121#endif
122
123	if (src_endian < 0)
124		src_endian = 0;
125	if (dst_endian < 0)
126		dst_endian = 0;
127
128	src_width = snd_pcm_format_width(src_format) / 8 - 1;
129	dst_width = snd_pcm_format_width(dst_format) / 8 - 1;
130
131	return src_width * 32 + src_endian * 16 + sign * 8 + dst_width * 2 + dst_endian;
132}
133
134int snd_pcm_plugin_build_linear(struct snd_pcm_substream *plug,
135				struct snd_pcm_plugin_format *src_format,
136				struct snd_pcm_plugin_format *dst_format,
137				struct snd_pcm_plugin **r_plugin)
138{
139	int err;
140	struct linear_priv *data;
141	struct snd_pcm_plugin *plugin;
142
143	snd_assert(r_plugin != NULL, return -ENXIO);
144	*r_plugin = NULL;
145
146	snd_assert(src_format->rate == dst_format->rate, return -ENXIO);
147	snd_assert(src_format->channels == dst_format->channels, return -ENXIO);
148	snd_assert(snd_pcm_format_linear(src_format->format) &&
149		   snd_pcm_format_linear(dst_format->format), return -ENXIO);
150
151	err = snd_pcm_plugin_build(plug, "linear format conversion",
152				   src_format, dst_format,
153				   sizeof(struct linear_priv), &plugin);
154	if (err < 0)
155		return err;
156	data = (struct linear_priv *)plugin->extra_data;
157	data->conv = conv_index(src_format->format, dst_format->format);
158	plugin->transfer = linear_transfer;
159	*r_plugin = plugin;
160	return 0;
161}
162
163#endif
164