direction: Add a couple of direction helper functions

src/pulse/direction.h

@@ -0,0 +1,37 @@
+#ifndef foodirectionhfoo
+#define foodirectionhfoo
+
+/***
+  This file is part of PulseAudio.
+
+  Copyright 2014 Intel Corporation
+
+  PulseAudio 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.
+
+  PulseAudio 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
+  General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with PulseAudio; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+  USA.
+***/
+
+#include <pulse/def.h>
+
+/** \file
+ * Utility functions for \ref pa_direction_t. */
+
+/** Return non-zero if the given value is a valid direction (either input,
+ * output or bidirectional). \since 6.0 */
+int pa_direction_valid(pa_direction_t direction) PA_GCC_CONST;
+
+/** Return a textual representation of the direction. \since 6.0 */
+const char *pa_direction_to_string(pa_direction_t direction);
+
+#endif