1 files changed, 109 insertions, 0 deletions
diff --git a/sound/core/oss/route.c b/sound/core/oss/route.c
new file mode 100644
index 00000000..c8171f57
--- /dev/null
+++ b/sound/core/oss/route.c
@@ -0,0 +1,109 @@
+/*
+ *  Route Plug-In
+ *  Copyright (c) 2000 by 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 <linux/time.h>
+#include <sound/core.h>
+#include <sound/pcm.h>
+#include "pcm_plugin.h"
+
+static void zero_areas(struct snd_pcm_plugin_channel *dvp, int ndsts,
+		       snd_pcm_uframes_t frames, snd_pcm_format_t format)
+{
+	int dst = 0;
+	for (; dst < ndsts; ++dst) {
+		if (dvp->wanted)
+			snd_pcm_area_silence(&dvp->area, 0, frames, format);
+		dvp->enabled = 0;
+		dvp++;
+	}
+}
+
+static inline void copy_area(const struct snd_pcm_plugin_channel *src_channel,
+			     struct snd_pcm_plugin_channel *dst_channel,
+			     snd_pcm_uframes_t frames, snd_pcm_format_t format)
+{
+	dst_channel->enabled = 1;
+	snd_pcm_area_copy(&src_channel->area, 0, &dst_channel->area, 0, frames, format);
+}
+
+static snd_pcm_sframes_t route_transfer(struct snd_pcm_plugin *plugin,
+					const struct snd_pcm_plugin_channel *src_channels,
+					struct snd_pcm_plugin_channel *dst_channels,
+					snd_pcm_uframes_t frames)
+{
+	int nsrcs, ndsts, dst;
+	struct snd_pcm_plugin_channel *dvp;
+	snd_pcm_format_t format;
+
+	if (snd_BUG_ON(!plugin || !src_channels || !dst_channels))
+		return -ENXIO;
+	if (frames == 0)
+		return 0;
+
+	nsrcs = plugin->src_format.channels;
+	ndsts = plugin->dst_format.channels;
+
+	format = plugin->dst_format.format;
+	dvp = dst_channels;
+	if (nsrcs <= 1) {
+		/* expand to all channels */
+		for (dst = 0; dst < ndsts; ++dst) {
+			copy_area(src_channels, dvp, frames, format);
+			dvp++;
+		}
+		return frames;
+	}
+
+	for (dst = 0; dst < ndsts && dst < nsrcs; ++dst) {
+		copy_area(src_channels, dvp, frames, format);
+		dvp++;
+		src_channels++;
+	}
+	if (dst < ndsts)
+		zero_areas(dvp, ndsts - dst, frames, format);
+	return frames;
+}
+
+int snd_pcm_plugin_build_route(struct snd_pcm_substream *plug,
+			       struct snd_pcm_plugin_format *src_format,
+			       struct snd_pcm_plugin_format *dst_format,
+			       struct snd_pcm_plugin **r_plugin)
+{
+	struct snd_pcm_plugin *plugin;
+	int err;
+
+	if (snd_BUG_ON(!r_plugin))
+		return -ENXIO;
+	*r_plugin = NULL;
+	if (snd_BUG_ON(src_format->rate != dst_format->rate))
+		return -ENXIO;
+	if (snd_BUG_ON(src_format->format != dst_format->format))
+		return -ENXIO;
+
+	err = snd_pcm_plugin_build(plug, "route conversion",
+				   src_format, dst_format, 0, &plugin);
+	if (err < 0)
+		return err;
+
+	plugin->transfer = route_transfer;
+	*r_plugin = plugin;
+	return 0;
+}