Created zero copy interface/framework, made use of it in usrp2 udp transport stuff.

4 files changed, 139 insertions, 69 deletions

diff --git a/host/include/uhd/transport/CMakeLists.txt b/host/include/uhd/transport/CMakeLists.txt
index 14b5ccd29..9a94ead1b 100644
--- a/host/include/uhd/transport/CMakeLists.txt
+++ b/host/include/uhd/transport/CMakeLists.txt
@@ -18,9 +18,9 @@
 
 INSTALL(FILES
     if_addrs.hpp
-    smart_buffer.hpp
     udp_simple.hpp
     udp_zero_copy.hpp
     vrt.hpp
+    zero_copy.hpp
     DESTINATION ${INCLUDE_DIR}/uhd/transport
 )
diff --git a/host/include/uhd/transport/smart_buffer.hpp b/host/include/uhd/transport/smart_buffer.hpp
deleted file mode 100644
index a9bc259e9..000000000
--- a/host/include/uhd/transport/smart_buffer.hpp
+++ /dev/null
@@ -1,45 +0,0 @@
-//
-// Copyright 2010 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_UHD_TRANSPORT_SMART_BUFFER_HPP
-#define INCLUDED_UHD_TRANSPORT_SMART_BUFFER_HPP
-
-#include <boost/asio/buffer.hpp>
-#include <boost/utility.hpp>
-#include <boost/shared_ptr.hpp>
-
-namespace uhd{ namespace transport{
-
-/*!
- * A buffer that knows how to free itself:
- *
- * This is just the smart buffer interface.
- * A transport implementation will have its own
- * internal (custom) smart buffer implementation.
- *
- * A smart buffer contains a boost asio const buffer.
- * On destruction, the buffer contents will be freed.
- */
-class smart_buffer : boost::noncopyable{
-public:
-    typedef boost::shared_ptr<smart_buffer> sptr;
-    virtual const boost::asio::const_buffer &get(void) const = 0;
-};
-
-}} //namespace
-
-#endif /* INCLUDED_UHD_TRANSPORT_SMART_BUFFER_HPP */
diff --git a/host/include/uhd/transport/udp_zero_copy.hpp b/host/include/uhd/transport/udp_zero_copy.hpp
index 0441a8e74..fd1cec46e 100644
--- a/host/include/uhd/transport/udp_zero_copy.hpp
+++ b/host/include/uhd/transport/udp_zero_copy.hpp
@@ -19,24 +19,22 @@
 #define INCLUDED_UHD_TRANSPORT_UDP_ZERO_COPY_HPP
 
 #include <uhd/config.hpp>
-#include <uhd/transport/smart_buffer.hpp>
-#include <boost/asio/buffer.hpp>
-#include <boost/utility.hpp>
+#include <uhd/transport/zero_copy.hpp>
 #include <boost/shared_ptr.hpp>
 
 namespace uhd{ namespace transport{
 
 /*!
  * A zero copy udp transport provides an efficient way to handle data.
- * by avoiding the extra copy when recv() is called on the socket.
- * Rather, the zero copy transport gives the caller a memory reference.
+ * by avoiding the extra copy when recv() or send() is called on the socket.
+ * Rather, the zero copy transport gives the caller memory references.
  * The caller informs the transport when it is finished with the reference.
  *
  * On linux systems, the zero copy transport can use a kernel packet ring.
  * If no platform specific solution is available, make returns a boost asio
- * implementation that wraps the functionality around a standard recv() call.
+ * implementation that wraps the functionality around a standard send/recv calls.
  */
-class UHD_API udp_zero_copy : boost::noncopyable{
+class UHD_API udp_zero_copy : public zero_copy_if{
 public:
     typedef boost::shared_ptr<udp_zero_copy> sptr;
 
@@ -54,22 +52,6 @@ public:
      * \param port a string representing the destination port
      */
     static sptr make(const std::string &addr, const std::string &port);
-
-    /*!
-     * Send a single buffer.
-     * Blocks until the data is sent.
-     * \param buff single asio buffer
-     * \return the number of bytes sent
-     */
-    virtual size_t send(const boost::asio::const_buffer &buff) = 0;
-
-    /*!
-     * Receive a buffer.
-     * Blocks until data is received or a timeout occurs.
-     * The memory is managed by the implementation.
-     * \return a smart buffer (empty on timeout)
-     */
-    virtual smart_buffer::sptr recv(void) = 0;
 };
 
 }} //namespace
diff --git a/host/include/uhd/transport/zero_copy.hpp b/host/include/uhd/transport/zero_copy.hpp
new file mode 100644
index 000000000..4fc1df9de
--- /dev/null
+++ b/host/include/uhd/transport/zero_copy.hpp
@@ -0,0 +1,133 @@
+//
+// Copyright 2010 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_UHD_TRANSPORT_ZERO_COPY_HPP
+#define INCLUDED_UHD_TRANSPORT_ZERO_COPY_HPP
+
+#include <uhd/config.hpp>
+#include <boost/asio/buffer.hpp>
+#include <boost/utility.hpp>
+#include <boost/shared_ptr.hpp>
+
+namespace uhd{ namespace transport{
+
+/*!
+ * A managed receive buffer:
+ * Contains a reference to transport-managed memory,
+ * and a method to release the memory after reading.
+ */
+class UHD_API managed_recv_buffer : boost::noncopyable{
+public:
+    typedef boost::shared_ptr<managed_recv_buffer> sptr;
+
+    /*!
+     * Signal to the transport that we are done with the buffer.
+     * This should be called to release the buffer to the transport.
+     * After calling, the referenced memory should be considered invalid.
+     */
+    virtual void done(void) = 0;
+
+    /*!
+     * Get the size of the underlying buffer.
+     * \return the number of bytes
+     */
+    size_t size(void){
+        return boost::asio::buffer_size(this->get());
+    }
+
+    /*!
+     * Get a pointer to the underlying buffer.
+     * \return a pointer into memory
+     */
+    template <class T> T cast(void){
+        return boost::asio::buffer_cast<T>(this->get());
+    }
+
+private:
+    /*!
+     * Get a reference to the internal const buffer.
+     * The buffer has a reference to memory and a size.
+     * \return a boost asio const buffer
+     */
+    virtual const boost::asio::const_buffer &get(void) = 0;
+};
+
+/*!
+ * A managed send buffer:
+ * Contains a reference to transport-managed memory,
+ * and a method to release the memory after writing.
+ */
+class UHD_API managed_send_buffer : boost::noncopyable{
+public:
+    typedef boost::shared_ptr<managed_send_buffer> sptr;
+
+    /*!
+     * Signal to the transport that we are done with the buffer.
+     * This should be called to commit the write to the transport object.
+     * After calling, the referenced memory should be considered invalid.
+     * \param num_bytes the number of bytes written into the buffer
+     */
+    virtual void done(size_t num_bytes) = 0;
+
+    /*!
+     * Get the size of the underlying buffer.
+     * \return the number of bytes
+     */
+    size_t size(void){
+        return boost::asio::buffer_size(this->get());
+    }
+
+    /*!
+     * Get a pointer to the underlying buffer.
+     * \return a pointer into memory
+     */
+    template <class T> T cast(void){
+        return boost::asio::buffer_cast<T>(this->get());
+    }
+
+private:
+    /*!
+     * Get a reference to the internal mutable buffer.
+     * The buffer has a reference to memory and a size.
+     * \return a boost asio mutable buffer
+     */
+    virtual const boost::asio::mutable_buffer &get(void) = 0;
+};
+
+/*!
+ * A zero-copy interface for transport objects.
+ * Provides a way to get send and receive buffers
+ * with memory managed by the transport object.
+ */
+class UHD_API zero_copy_if : boost::noncopyable{
+public:
+    typedef boost::shared_ptr<zero_copy_if> sptr;
+
+    /*!
+     * Get a new receive buffer from this transport object.
+     */
+    virtual managed_recv_buffer::sptr get_recv_buff(void) = 0;
+
+    /*!
+     * Get a new send buffer from this transport object.
+     */
+    virtual managed_send_buffer::sptr get_send_buff(void) = 0;
+};
+
+}} //namespace
+
+#endif /* INCLUDED_UHD_TRANSPORT_ZERO_COPY_HPP */