6 files changed, 59 insertions, 62 deletions
diff --git a/gnuradio-runtime/include/gnuradio/block.h b/gnuradio-runtime/include/gnuradio/block.h
index 5fd1316951..882a0466a8 100644
--- a/gnuradio-runtime/include/gnuradio/block.h
+++ b/gnuradio-runtime/include/gnuradio/block.h
@@ -540,8 +540,7 @@ public:
      * that is incompatible with the default buffer type created by this block.
      *
      */
-    buffer_sptr
-    replace_buffer(uint32_t src_port, uint32_t dst_port, block_sptr block_owner);
+    buffer_sptr replace_buffer(size_t src_port, size_t dst_port, block_sptr block_owner);
 
     // --------------- Performance counter functions -------------
 
@@ -943,7 +942,7 @@ protected:
      * that the downstream max number of items must be passed in to this
      * function for consideration.
      */
-    buffer_sptr allocate_buffer(int port,
+    buffer_sptr allocate_buffer(size_t port,
                                 int downstream_max_nitems,
                                 uint64_t downstream_lcm_nitems,
                                 uint32_t downstream_max_out_mult);
diff --git a/gnuradio-runtime/include/gnuradio/buffer_double_mapped.h b/gnuradio-runtime/include/gnuradio/buffer_double_mapped.h
index d4bfa28ff4..99b85fcc76 100644
--- a/gnuradio-runtime/include/gnuradio/buffer_double_mapped.h
+++ b/gnuradio-runtime/include/gnuradio/buffer_double_mapped.h
@@ -22,20 +22,6 @@ namespace gr {
 class vmcircbuf;
 
 /*!
- * \brief Note this function is only used and really intended to be used in
- *  qa_buffer.cc for the unit tests of buffer_double_mapped.
- *
- */
-GR_RUNTIME_API buffer_sptr make_buffer_double_mapped(int nitems,
-                                                     size_t sizeof_item,
-                                                     uint64_t downstream_lcm_nitems,
-                                                     uint32_t downstream_max_out_mult,
-                                                     block_sptr link = block_sptr(),
-                                                     block_sptr buf_owner = block_sptr());
-
-DEFINE_CUSTOM_BUFFER_TYPE(DEFAULT_NON_CUSTOM, make_buffer_double_mapped);
-
-/*!
  * \brief Single writer, multiple reader fifo.
  * \ingroup internal
  */
@@ -44,6 +30,13 @@ class GR_RUNTIME_API buffer_double_mapped : public buffer
 public:
     static buffer_type type;
 
+    static buffer_sptr make_buffer(int nitems,
+                                   size_t sizeof_item,
+                                   uint64_t downstream_lcm_nitems,
+                                   uint32_t downstream_max_out_mult,
+                                   block_sptr link = block_sptr(),
+                                   block_sptr buf_owner = block_sptr());
+
     gr::logger_ptr d_logger;
     gr::logger_ptr d_debug_logger;
 
diff --git a/gnuradio-runtime/include/gnuradio/buffer_type.h b/gnuradio-runtime/include/gnuradio/buffer_type.h
index b304899750..db8180ead0 100644
--- a/gnuradio-runtime/include/gnuradio/buffer_type.h
+++ b/gnuradio-runtime/include/gnuradio/buffer_type.h
@@ -18,20 +18,11 @@
 #include <functional>
 #include <mutex>
 #include <string>
+#include <typeinfo>
 #include <vector>
 
 namespace gr {
 
-// This is the function pointer declaration for the factory-like functions
-// used to create buffer subclasses
-typedef buffer_sptr (*factory_func_ptr)(int nitems,
-                                        size_t sizeof_item,
-                                        uint64_t downstrea_lcm_nitems,
-                                        uint32_t downstream_max_out_mult,
-                                        block_sptr link,
-                                        block_sptr buf_owner);
-
-
 /*!
  * \brief Base class for describing a buffer's type.
  */
@@ -45,10 +36,7 @@ public:
 
     // Temporarily define copy constructor to work around pybind issue with
     // default non-copyable function argument
-    buffer_type_base(buffer_type_base const& other)
-        : d_name(other.d_name), d_factory(other.d_factory)
-    {
-    }
+    buffer_type_base(buffer_type_base const& other) : d_name(other.d_name) {}
 
     void operator=(buffer_type_base const&) = delete;
 
@@ -76,42 +64,55 @@ public:
     /*!
      * \brief Make and return a buffer subclass of the corresponding type
      */
-    inline buffer_sptr make_buffer(int nitems,
-                                   size_t sizeof_item,
-                                   uint64_t downstream_lcm_nitems,
-                                   uint32_t downstream_max_out_mult,
-                                   block_sptr link,
-                                   block_sptr buf_owner) const
+    virtual buffer_sptr
+    make_buffer([[maybe_unused]] int nitems,
+                [[maybe_unused]] size_t sizeof_item,
+                [[maybe_unused]] uint64_t downstream_lcm_nitems,
+                [[maybe_unused]] uint32_t downstream_max_out_mult,
+                [[maybe_unused]] block_sptr link = block_sptr(),
+                [[maybe_unused]] block_sptr buf_owner = block_sptr()) const
     {
-        // Delegate call to factory function
-        return d_factory(nitems,
-                         sizeof_item,
-                         downstream_lcm_nitems,
-                         downstream_max_out_mult,
-                         link,
-                         buf_owner);
+        // NOTE: this is *never* intended to be called directly, instead the overridden
+        // version from a derived class (created from the template below) will be
+        // called.
+        return nullptr;
     }
 
 protected:
     const std::string d_name;
-    factory_func_ptr d_factory;
 
-    // Protected constructor
-    buffer_type_base(const char* name, factory_func_ptr factory_func)
-        : d_name(name), d_factory(factory_func)
-    {
-    }
+    buffer_type_base(const std::string name) : d_name(name) {}
 };
 
 typedef const buffer_type_base& buffer_type;
 typedef std::vector<std::reference_wrapper<const buffer_type_base>> gr_vector_buffer_type;
 
-#define DEFINE_CUSTOM_BUFFER_TYPE(CLASSNAME, FACTORY_FUNC_PTR)                    \
-    class GR_RUNTIME_API buftype_##CLASSNAME : public buffer_type_base            \
-    {                                                                             \
-    public:                                                                       \
-        buftype_##CLASSNAME() : buffer_type_base(#CLASSNAME, FACTORY_FUNC_PTR) {} \
-    };
+/*!
+ * \brief Template used to create buffer types. Note that the factory_class parameter
+ * must contain a static function make_buffer() that matches the signature below
+ * and will be used to create instances of the corresponding buffer type.
+ */
+template <typename classname, typename factory_class>
+struct buftype : public buffer_type_base {
+public:
+    using factory = factory_class;
+    buffer_sptr make_buffer(int nitems,
+                            size_t sizeof_item,
+                            uint64_t downstream_lcm_nitems,
+                            uint32_t downstream_max_out_mult,
+                            block_sptr link = block_sptr(),
+                            block_sptr buf_owner = block_sptr()) const override
+    {
+        return factory::make_buffer(nitems,
+                                    sizeof_item,
+                                    downstream_lcm_nitems,
+                                    downstream_max_out_mult,
+                                    link,
+                                    buf_owner);
+    }
+
+    buftype<classname, factory_class>() : buffer_type_base(typeid(classname).name()) {}
+};
 
 } // namespace gr
 
diff --git a/gnuradio-runtime/include/gnuradio/custom_lock.h b/gnuradio-runtime/include/gnuradio/custom_lock.h
index 5011abe5eb..b8d9ed6d47 100644
--- a/gnuradio-runtime/include/gnuradio/custom_lock.h
+++ b/gnuradio-runtime/include/gnuradio/custom_lock.h
@@ -67,4 +67,4 @@ private:
 
 } /* namespace gr */
 
-#endif /* INCLUDED_GR_CUSTOM_LOCK_H */
-\ No newline at end of file
+#endif /* INCLUDED_GR_CUSTOM_LOCK_H */
diff --git a/gnuradio-runtime/include/gnuradio/host_buffer.h b/gnuradio-runtime/include/gnuradio/host_buffer.h
index ac09cdfe33..d5b7e2230b 100644
--- a/gnuradio-runtime/include/gnuradio/host_buffer.h
+++ b/gnuradio-runtime/include/gnuradio/host_buffer.h
@@ -23,6 +23,13 @@ public:
 
     static buffer_type type;
 
+    static buffer_sptr make_buffer(int nitems,
+                                   size_t sizeof_item,
+                                   uint64_t downstream_lcm_nitems,
+                                   uint32_t downstream_max_out_mult,
+                                   block_sptr link = block_sptr(),
+                                   block_sptr buf_owner = block_sptr());
+
     virtual ~host_buffer();
 
     /*!
@@ -117,10 +124,6 @@ private:
                 block_sptr buf_owner);
 };
 
-// See buffer_type.h for details on this macro. It is used here to generate
-// compile-time class representing the host_buffer classes "type".
-DEFINE_CUSTOM_BUFFER_TYPE(HOST_BUFFER, &host_buffer::make_host_buffer);
-
 } // namespace gr
 
 #endif /* INCLUDED_HOST_BUFFER_H */
diff --git a/gnuradio-runtime/include/gnuradio/io_signature.h b/gnuradio-runtime/include/gnuradio/io_signature.h
index 60ac798f79..5424e506ff 100644
--- a/gnuradio-runtime/include/gnuradio/io_signature.h
+++ b/gnuradio-runtime/include/gnuradio/io_signature.h
@@ -123,7 +123,8 @@ public:
      *
      * \param min_streams  specify minimum number of streams (>= 0)
      * \param max_streams  specify maximum number of streams (>= min_streams or -1 ->
-     * infinite) \param sizeof_stream_items specify the size of the items in the streams
+     * infinite)
+     * \param sizeof_stream_items specify the size of the items in the streams
      * \param buftypes  the type of buffer each stream will should use
      *
      * If there are more streams than there are entries in