providing additional control over GNU Radio buffer allocation size for latency effects etc

unlimited io_signatures of -1 should work correctly with this patch now

4 files changed, 44 insertions, 2 deletions

diff --git a/gnuradio-core/src/lib/runtime/gr_basic_block.cc b/gnuradio-core/src/lib/runtime/gr_basic_block.cc
index d7263b92d..3d809aa8b 100644
--- a/gnuradio-core/src/lib/runtime/gr_basic_block.cc
+++ b/gnuradio-core/src/lib/runtime/gr_basic_block.cc
@@ -45,7 +45,9 @@ gr_basic_block::gr_basic_block(const std::string &name,
     d_input_signature(input_signature),
     d_output_signature(output_signature),
     d_unique_id(s_next_id++),
-    d_color(WHITE)
+    d_color(WHITE),
+    d_max_output_buffer(std::max(output_signature->max_streams(),1), -1),
+    d_min_output_buffer(std::max(output_signature->max_streams(),1), -1)
 {
     s_ncurrently_allocated++;
 }
diff --git a/gnuradio-core/src/lib/runtime/gr_basic_block.h b/gnuradio-core/src/lib/runtime/gr_basic_block.h
index 4d03b878e..4d16014dd 100644
--- a/gnuradio-core/src/lib/runtime/gr_basic_block.h
+++ b/gnuradio-core/src/lib/runtime/gr_basic_block.h
@@ -29,7 +29,9 @@
 #include <boost/enable_shared_from_this.hpp>
 #include <boost/function.hpp>
 #include <gr_msg_accepter.h>
+#include <gr_io_signature.h>
 #include <string>
+#include <iostream>
 
 /*!
  * \brief The abstract base class for all signal processing blocks.
@@ -73,6 +75,8 @@ protected:
     gr_io_signature_sptr d_output_signature;
     long                 d_unique_id;
     vcolor               d_color;
+    std::vector<long>    d_max_output_buffer;
+    std::vector<long>    d_min_output_buffer;
 
     gr_basic_block(void){} //allows pure virtual interface sub-classes
 
@@ -104,7 +108,21 @@ public:
     gr_io_signature_sptr input_signature() const  { return d_input_signature; }
     gr_io_signature_sptr output_signature() const { return d_output_signature; }
     gr_basic_block_sptr to_basic_block(); // Needed for Python type coercion
-
+    long max_output_buffer(size_t i){ return d_max_output_buffer.size()>i?d_max_output_buffer[i]:d_max_output_buffer[0]; }
+    void set_max_output_buffer(long max_output_buffer){ 
+        for(int i=0; i<output_signature()->max_streams(); i++){
+            set_max_output_buffer(max_output_buffer, i);
+        }
+    }
+    void set_max_output_buffer(long max_output_buffer, int port){ d_max_output_buffer[port] = max_output_buffer; }
+    long min_output_buffer(size_t i){ return d_min_output_buffer.size()>i?d_min_output_buffer[i]:d_min_output_buffer[0]; }
+    void set_min_output_buffer(long min_output_buffer){ 
+        for(int i=0; i<output_signature()->max_streams(); i++){
+            set_min_output_buffer(min_output_buffer, i);
+        }
+    }
+    void set_min_output_buffer(long min_output_buffer, int port){ d_min_output_buffer[port] = min_output_buffer; }
+    
     /*!
      * \brief Confirm that ninputs and noutputs is an acceptable combination.
      *
diff --git a/gnuradio-core/src/lib/runtime/gr_basic_block.i b/gnuradio-core/src/lib/runtime/gr_basic_block.i
index e43cc114c..848017dd8 100644
--- a/gnuradio-core/src/lib/runtime/gr_basic_block.i
+++ b/gnuradio-core/src/lib/runtime/gr_basic_block.i
@@ -42,6 +42,12 @@ public:
     long unique_id() const;
     gr_basic_block_sptr to_basic_block();
     bool check_topology (int ninputs, int noutputs);
+    long max_output_buffer(int i);
+    void set_max_output_buffer(long max_output_buffer);
+    void set_max_output_buffer(long max_output_buffer, int port);
+    long min_output_buffer(int i);
+    void set_min_output_buffer(long min_output_buffer);
+    void set_min_output_buffer(long min_output_buffer, int port);
 };
 
 %rename(block_ncurrently_allocated) gr_basic_block_ncurrently_allocated;
diff --git a/gnuradio-core/src/lib/runtime/gr_flat_flowgraph.cc b/gnuradio-core/src/lib/runtime/gr_flat_flowgraph.cc
index 030e2d97d..fb375b0f3 100644
--- a/gnuradio-core/src/lib/runtime/gr_flat_flowgraph.cc
+++ b/gnuradio-core/src/lib/runtime/gr_flat_flowgraph.cc
@@ -114,6 +114,21 @@ gr_flat_flowgraph::allocate_buffer(gr_basic_block_sptr block, int port)
   // ensure we have a buffer at least twice their decimation factor*output_multiple
   gr_basic_block_vector_t blocks = calc_downstream_blocks(block, port);
 
+
+  // limit buffer size if indicated
+  if(block->max_output_buffer(port) > 0){
+//    std::cout << "constraining output items to " << block->max_output_buffer(port) << "\n";
+    nitems = std::min((long)nitems, (long)block->max_output_buffer(port));
+    nitems -= nitems%grblock->output_multiple();
+    if( nitems < 1 )
+      throw std::runtime_error("problems allocating a buffer with the given max output buffer constraint!");
+  } else if(block->min_output_buffer(port) > 0){
+    nitems = std::max((long)nitems, (long)block->min_output_buffer(port));
+    nitems -= nitems%grblock->output_multiple();
+    if( nitems < 1 )
+      throw std::runtime_error("problems allocating a buffer with the given min output buffer constraint!");
+  }
+
   for (gr_basic_block_viter_t p = blocks.begin(); p != blocks.end(); p++) {
     gr_block_sptr dgrblock = cast_to_block_sptr(*p);
     if (!dgrblock)
@@ -125,6 +140,7 @@ gr_flat_flowgraph::allocate_buffer(gr_basic_block_sptr block, int port)
     nitems = std::max(nitems, static_cast<int>(2*(decimation*multiple+history)));
   }
 
+//  std::cout << "gr_make_buffer(" << nitems << ", " << item_size << ", " << grblock << "\n";
   return gr_make_buffer(nitems, item_size, grblock);
 }