usrp3: Added SW muxer/demuxer for the zero_copy interface

- Can be used to share a single zero_copy_if object with multiple
  streams
- Allows creating of virtual streams that are indistinguishable
  from low-level streams

1 files changed, 72 insertions, 0 deletions

diff --git a/host/include/uhd/transport/muxed_zero_copy_if.hpp b/host/include/uhd/transport/muxed_zero_copy_if.hpp
new file mode 100644
index 000000000..17213885e
--- /dev/null
+++ b/host/include/uhd/transport/muxed_zero_copy_if.hpp
@@ -0,0 +1,72 @@
+//
+// Copyright 2016 Ettus Research LLC
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 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 General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+//
+
+#ifndef INCLUDED_LIBUHD_TRANSPORT_MUXED_ZERO_COPY_IF_HPP
+#define INCLUDED_LIBUHD_TRANSPORT_MUXED_ZERO_COPY_IF_HPP
+
+#include <uhd/transport/zero_copy.hpp>
+#include <uhd/config.hpp>
+#include <boost/function.hpp>
+#include <boost/noncopyable.hpp>
+#include <stdint.h>
+
+namespace uhd { namespace transport {
+
+/*!
+ * Implements a software muxed-demuxed zero-copy transport
+ * This is a wrapper around a base transport that allows
+ * creation of virtual zero_copy_if streams that are
+ * indistinguishable from physical transport streams.
+ * This class handles demuxing receive streams into the
+ * appropriate virtual streams with the given classifier
+ * function. A worker therad is spawned to handle the demuxing.
+ */
+class muxed_zero_copy_if : private boost::noncopyable {
+public:
+    typedef boost::shared_ptr<muxed_zero_copy_if> sptr;
+
+    /*!
+     * Function to classify the stream based on the payload.
+     * The classifier must return a stream number, an arbitrary
+     * identifier for a virtual stream that is consistent with
+     * the stream number used in the make_stream and remove_stream
+     * fuctions
+     * \param buff a pointer to the payload of the frame
+     * \param size number of bytes in the frame payload
+     * \return stream number
+     */
+    typedef boost::function<uint32_t(void* buff, size_t size)> stream_classifier_fn;
+
+    //! virtual dtor
+    virtual ~muxed_zero_copy_if() {}
+
+    //! Make a virtual transport for the specified stream number
+    virtual zero_copy_if::sptr make_stream(const uint32_t stream_num) = 0;
+
+    //! Unregister the stream number. All packets destined to the stream will be dropped.
+    virtual void remove_stream(const uint32_t stream_num) = 0;
+
+    //! Get number of frames dropped due to unregistered streams
+    virtual size_t get_num_dropped_frames() const = 0;
+
+    //! Make a new demuxer from a transport and parameters
+    static sptr make(zero_copy_if::sptr base_xport, stream_classifier_fn classify_fn, size_t max_streams);
+};
+
+}} //namespace uhd::transport
+
+#endif /* INCLUDED_LIBUHD_TRANSPORT_MUXED_ZERO_COPY_IF_HPP */