added pcm_empty plugin and .hgignore additions

.hgignore

@@ -28,6 +28,7 @@ ltconfig
 *.lo
 *.pc
 *.o
+*~
 include/config.h
 include/stamp-h1
 include/stamp-vh
@@ -36,3 +37,6 @@ utils/alsa-lib.spec
 alsalisp/alsalisp
 aserver/aserver
 src/pcm/pcm_symbols_list.c
+doc/doxygen/*
+test/namehint
+test/pcm

src/pcm/pcm_empty.c

@@ -0,0 +1,109 @@
+/**
+ * \file pcm/pcm_empty.c
+ * \ingroup PCM_Plugins
+ * \brief PCM Null Plugin Interface
+ * \author Jaroslav Kysela <perex@suse.cz>
+ * \date 2006
+ */
+/*
+ *  PCM - Null plugin
+ *  Copyright (c) 2006 by Jaroslav Kysela <perex@suse.cz>
+ *
+ *
+ *   This library is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU Lesser General Public License as
+ *   published by the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details.
+ *
+ *   You should have received a copy of the GNU Lesser 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 "pcm_local.h"
+#include "pcm_plugin.h"
+
+#ifndef PIC
+/* entry for static linking */
+const char *_snd_module_pcm_empty = "";
+#endif
+
+/*! \page pcm_plugins
+
+\section pcm_plugins_null Plugin: Null
+
+This plugin discards contents of a PCM stream or creates a stream with zero
+samples.
+
+Note: This implementation uses devices /dev/null (playback, must be writable)
+and /dev/full (capture, must be readable).
+
+\code
+pcm.name {
+        type null               # Null PCM
+}
+\endcode
+
+\subsection pcm_plugins_null_funcref Function reference
+
+<UL>
+  <LI>_snd_pcm_empty_open()
+</UL>
+
+*/
+
+/**
+ * \brief Creates a new Empty PCM
+ * \param pcmp Returns created PCM handle
+ * \param name Name of PCM
+ * \param root Root configuration node
+ * \param conf Configuration node with empty PCM description
+ * \param stream Stream type
+ * \param mode Stream mode
+ * \retval zero on success otherwise a negative error code
+ * \warning Using of this function might be dangerous in the sense
+ *          of compatibility reasons. The prototype might be freely
+ *          changed in future.
+ */
+int _snd_pcm_empty_open(snd_pcm_t **pcmp, const char *name ATTRIBUTE_UNUSED,
+		        snd_config_t *root, snd_config_t *conf, 
+		        snd_pcm_stream_t stream, int mode)
+{
+	snd_config_t *slave = NULL, *sconf;
+	snd_config_iterator_t i, next;
+	int err;
+
+	snd_config_for_each(i, next, conf) {
+		snd_config_t *n = snd_config_iterator_entry(i);
+		const char *id;
+		if (snd_config_get_id(n, &id) < 0)
+			continue;
+		if (snd_pcm_conf_generic_id(id))
+			continue;
+		if (strcmp(id, "slave") == 0) {
+			slave = n;
+			continue;
+		}
+		SNDERR("Unknown field %s", id);
+		return -EINVAL;
+	}
+	if (!slave) {
+		SNDERR("slave is not defined");
+		return -EINVAL;
+	}
+	err = snd_pcm_slave_conf(root, slave, &sconf, 0);
+	if (err < 0)
+		return err;
+	err = snd_pcm_open_slave(pcmp, root, sconf, stream, mode, conf);
+	snd_config_delete(sconf);
+	return err;
+}
+#ifndef DOC_HIDDEN
+SND_DLSYM_BUILD_VERSION(_snd_pcm_empty_open, SND_PCM_DLSYM_VERSION);
+#endif