summaryrefslogtreecommitdiffstats
path: root/sound/core/oss/linear.c
blob: 12ed27a57b275a2c6f491888d3ce6e91211f7ab8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
/*
 *  Linear conversion Plug-In
 *  Copyright (c) 1999 by Jaroslav Kysela <perex@suse.cz>,
 *			  Abramo Bagnara <abramo@alsa-project.org>
 *
 *
 *   This library is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Library General Public License as
 *   published by the Free Software Foundation; either version 2 of
 *   the License, or (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU Library General Public License for more details.
 *
 *   You should have received a copy of the GNU Library General Public
 *   License along with this library; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 */

#include <sound/driver.h>
#include <linux/time.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include "pcm_plugin.h"

/*
 *  Basic linear conversion plugin
 */
 
typedef struct linear_private_data {
	int conv;
} linear_t;

static void convert(snd_pcm_plugin_t *plugin,
		    const snd_pcm_plugin_channel_t *src_channels,
		    snd_pcm_plugin_channel_t *dst_channels,
		    snd_pcm_uframes_t frames)
{
#define CONV_LABELS
#include "plugin_ops.h"
#undef CONV_LABELS
	linear_t *data = (linear_t *)plugin->extra_data;
	void *conv = conv_labels[data->conv];
	int channel;
	int nchannels = plugin->src_format.channels;
	for (channel = 0; channel < nchannels; ++channel) {
		char *src;
		char *dst;
		int src_step, dst_step;
		snd_pcm_uframes_t frames1;
		if (!src_channels[channel].enabled) {
			if (dst_channels[channel].wanted)
				snd_pcm_area_silence(&dst_channels[channel].area, 0, frames, plugin->dst_format.format);
			dst_channels[channel].enabled = 0;
			continue;
		}
		dst_channels[channel].enabled = 1;
		src = src_channels[channel].area.addr + src_channels[channel].area.first / 8;
		dst = dst_channels[channel].area.addr + dst_channels[channel].area.first / 8;
		src_step = src_channels[channel].area.step / 8;
		dst_step = dst_channels[channel].area.step / 8;
		frames1 = frames;
		while (frames1-- > 0) {
			goto *conv;
#define CONV_END after
#include "plugin_ops.h"
#undef CONV_END
		after:
			src += src_step;
			dst += dst_step;
		}
	}
}

static snd_pcm_sframes_t linear_transfer(snd_pcm_plugin_t *plugin,
			       const snd_pcm_plugin_channel_t *src_channels,
			       snd_pcm_plugin_channel_t *dst_channels,
			       snd_pcm_uframes_t frames)
{
	linear_t *data;

	snd_assert(plugin != NULL && src_channels != NULL && dst_channels != NULL, return -ENXIO);
	data = (linear_t *)plugin->extra_data;
	if (frames == 0)
		return 0;
#ifdef CONFIG_SND_DEBUG
	{
		unsigned int channel;
		for (channel = 0; channel < plugin->src_format.channels; channel++) {
			snd_assert(src_channels[channel].area.first % 8 == 0 &&
				   src_channels[channel].area.step % 8 == 0,
				   return -ENXIO);
			snd_assert(dst_channels[channel].area.first % 8 == 0 &&
				   dst_channels[channel].area.step % 8 == 0,
				   return -ENXIO);
		}
	}
#endif
	convert(plugin, src_channels, dst_channels, frames);
	return frames;
}

int conv_index(int src_format, int dst_format)
{
	int src_endian, dst_endian, sign, src_width, dst_width;

	sign = (snd_pcm_format_signed(src_format) !=
		snd_pcm_format_signed(dst_format));
#ifdef SNDRV_LITTLE_ENDIAN
	src_endian = snd_pcm_format_big_endian(src_format);
	dst_endian = snd_pcm_format_big_endian(dst_format);
#else
	src_endian = snd_pcm_format_little_endian(src_format);
	dst_endian = snd_pcm_format_little_endian(dst_format);
#endif

	if (src_endian < 0)
		src_endian = 0;
	if (dst_endian < 0)
		dst_endian = 0;

	src_width = snd_pcm_format_width(src_format) / 8 - 1;
	dst_width = snd_pcm_format_width(dst_format) / 8 - 1;

	return src_width * 32 + src_endian * 16 + sign * 8 + dst_width * 2 + dst_endian;
}

int snd_pcm_plugin_build_linear(snd_pcm_plug_t *plug,
				snd_pcm_plugin_format_t *src_format,
				snd_pcm_plugin_format_t *dst_format,
				snd_pcm_plugin_t **r_plugin)
{
	int err;
	struct linear_private_data *data;
	snd_pcm_plugin_t *plugin;

	snd_assert(r_plugin != NULL, return -ENXIO);
	*r_plugin = NULL;

	snd_assert(src_format->rate == dst_format->rate, return -ENXIO);
	snd_assert(src_format->channels == dst_format->channels, return -ENXIO);
	snd_assert(snd_pcm_format_linear(src_format->format) &&
		   snd_pcm_format_linear(dst_format->format), return -ENXIO);

	err = snd_pcm_plugin_build(plug, "linear format conversion",
				   src_format, dst_format,
				   sizeof(linear_t), &plugin);
	if (err < 0)
		return err;
	data = (linear_t *)plugin->extra_data;
	data->conv = conv_index(src_format->format, dst_format->format);
	plugin->transfer = linear_transfer;
	*r_plugin = plugin;
	return 0;
}