164 lines
4.9 KiB
C
164 lines
4.9 KiB
C
/*
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* Linear conversion Plug-In
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* Copyright (c) 1999 by Jaroslav Kysela <perex@suse.cz>,
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* Abramo Bagnara <abramo@alsa-project.org>
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*
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*
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* This library is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Library General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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#include <sound/driver.h>
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#ifdef CONFIG_SND_PCM_OSS_PLUGINS
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#include <linux/time.h>
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#include <sound/core.h>
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#include <sound/pcm.h>
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#include "pcm_plugin.h"
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/*
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* Basic linear conversion plugin
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*/
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struct linear_priv {
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int conv;
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};
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static void convert(struct snd_pcm_plugin *plugin,
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const struct snd_pcm_plugin_channel *src_channels,
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struct snd_pcm_plugin_channel *dst_channels,
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snd_pcm_uframes_t frames)
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{
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#define CONV_LABELS
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#include "plugin_ops.h"
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#undef CONV_LABELS
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struct linear_priv *data = (struct linear_priv *)plugin->extra_data;
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void *conv = conv_labels[data->conv];
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int channel;
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int nchannels = plugin->src_format.channels;
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for (channel = 0; channel < nchannels; ++channel) {
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char *src;
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char *dst;
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int src_step, dst_step;
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snd_pcm_uframes_t frames1;
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if (!src_channels[channel].enabled) {
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if (dst_channels[channel].wanted)
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snd_pcm_area_silence(&dst_channels[channel].area, 0, frames, plugin->dst_format.format);
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dst_channels[channel].enabled = 0;
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continue;
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}
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dst_channels[channel].enabled = 1;
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src = src_channels[channel].area.addr + src_channels[channel].area.first / 8;
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dst = dst_channels[channel].area.addr + dst_channels[channel].area.first / 8;
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src_step = src_channels[channel].area.step / 8;
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dst_step = dst_channels[channel].area.step / 8;
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frames1 = frames;
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while (frames1-- > 0) {
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goto *conv;
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#define CONV_END after
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#include "plugin_ops.h"
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#undef CONV_END
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after:
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src += src_step;
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dst += dst_step;
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}
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}
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}
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static snd_pcm_sframes_t linear_transfer(struct snd_pcm_plugin *plugin,
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const struct snd_pcm_plugin_channel *src_channels,
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struct snd_pcm_plugin_channel *dst_channels,
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snd_pcm_uframes_t frames)
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{
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struct linear_priv *data;
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snd_assert(plugin != NULL && src_channels != NULL && dst_channels != NULL, return -ENXIO);
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data = (struct linear_priv *)plugin->extra_data;
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if (frames == 0)
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return 0;
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#ifdef CONFIG_SND_DEBUG
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{
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unsigned int channel;
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for (channel = 0; channel < plugin->src_format.channels; channel++) {
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snd_assert(src_channels[channel].area.first % 8 == 0 &&
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src_channels[channel].area.step % 8 == 0,
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return -ENXIO);
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snd_assert(dst_channels[channel].area.first % 8 == 0 &&
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dst_channels[channel].area.step % 8 == 0,
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return -ENXIO);
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}
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}
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#endif
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convert(plugin, src_channels, dst_channels, frames);
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return frames;
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}
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static int conv_index(int src_format, int dst_format)
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{
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int src_endian, dst_endian, sign, src_width, dst_width;
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sign = (snd_pcm_format_signed(src_format) !=
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snd_pcm_format_signed(dst_format));
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#ifdef SNDRV_LITTLE_ENDIAN
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src_endian = snd_pcm_format_big_endian(src_format);
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dst_endian = snd_pcm_format_big_endian(dst_format);
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#else
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src_endian = snd_pcm_format_little_endian(src_format);
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dst_endian = snd_pcm_format_little_endian(dst_format);
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#endif
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if (src_endian < 0)
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src_endian = 0;
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if (dst_endian < 0)
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dst_endian = 0;
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src_width = snd_pcm_format_width(src_format) / 8 - 1;
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dst_width = snd_pcm_format_width(dst_format) / 8 - 1;
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return src_width * 32 + src_endian * 16 + sign * 8 + dst_width * 2 + dst_endian;
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}
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int snd_pcm_plugin_build_linear(struct snd_pcm_substream *plug,
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struct snd_pcm_plugin_format *src_format,
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struct snd_pcm_plugin_format *dst_format,
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struct snd_pcm_plugin **r_plugin)
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{
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int err;
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struct linear_priv *data;
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struct snd_pcm_plugin *plugin;
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snd_assert(r_plugin != NULL, return -ENXIO);
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*r_plugin = NULL;
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snd_assert(src_format->rate == dst_format->rate, return -ENXIO);
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snd_assert(src_format->channels == dst_format->channels, return -ENXIO);
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snd_assert(snd_pcm_format_linear(src_format->format) &&
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snd_pcm_format_linear(dst_format->format), return -ENXIO);
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err = snd_pcm_plugin_build(plug, "linear format conversion",
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src_format, dst_format,
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sizeof(struct linear_priv), &plugin);
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if (err < 0)
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return err;
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data = (struct linear_priv *)plugin->extra_data;
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data->conv = conv_index(src_format->format, dst_format->format);
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plugin->transfer = linear_transfer;
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*r_plugin = plugin;
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return 0;
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}
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#endif
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