sound/core/oss/linear.c

   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
  36 struct linear_priv {
  37         int conv;
  38 };
  39
  40 static 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
  81 static 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
 109 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
 134 int 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