1 files changed, 149 insertions, 0 deletions
diff --git a/lib/gain_handler.cpp b/lib/gain_handler.cpp
new file mode 100644
index 000000000..72343c1a4
--- /dev/null
+++ b/lib/gain_handler.cpp
@@ -0,0 +1,149 @@
+//
+// Copyright 2010 Ettus Research LLC
+//
+
+#include <usrp_uhd/gain_handler.hpp>
+#include <usrp_uhd/utils.hpp>
+#include <boost/assign/list_of.hpp>
+#include <boost/foreach.hpp>
+#include <boost/format.hpp>
+#include <vector>
+
+using namespace usrp_uhd;
+
+/***********************************************************************
+ * Helper functions and macros
+ **********************************************************************/
+#define GET_PROP_NAMES() \
+    wax::cast<prop_names_t>((*_wax_obj_ptr)[_gain_names_prop])
+
+/*!
+ * Helper function to simplify getting a named gain (also min, max, step).
+ */
+static gain_t get_named_gain(wax::obj::ptr wax_obj_ptr, wax::type prop, std::string name){
+    return wax::cast<gain_t>((*wax_obj_ptr)[named_prop_t(prop, name)]);
+}
+
+/***********************************************************************
+ * Class methods of gain handler
+ **********************************************************************/
+gain_handler::~gain_handler(void){
+    /* NOP */
+}
+
+void gain_handler::_check_key(const wax::type &key_){
+    wax::type key; std::string name;
+    tie(key, name) = extract_named_prop(key_);
+    
+    try{
+        //only handle non wildcard names
+        ASSERT_THROW(name != "");
+
+        //only handle these gain props
+        ASSERT_THROW(
+            _is_equal(key, _gain_prop)     or
+            _is_equal(key, _gain_min_prop) or
+            _is_equal(key, _gain_max_prop) or
+            _is_equal(key, _gain_step_prop)
+        );
+
+        //check that the name is allowed
+        prop_names_t prop_names = GET_PROP_NAMES();
+        ASSERT_THROW(not std::has(prop_names.begin(), prop_names.end(), name));
+
+        //if we get here, throw an exception
+        throw std::invalid_argument(str(
+            boost::format("Unknown gain name %s") % name
+        ));
+    }
+    catch(const std::assert_error &){}
+}
+
+bool gain_handler::intercept_get(const wax::type &key, wax::type &val){
+    _check_key(key); //verify the key
+
+    // use a vector of tuples to map properties to a reducer function
+    // we cant use a map because the wax::type cant be sorted
+    typedef boost::function<gain_t(gain_t, gain_t)> reducer_t;
+    typedef boost::tuple<wax::type, reducer_t> tuple_t;
+    reducer_t reducer_sum = boost::bind(std::sum<gain_t>, _1, _2);
+    reducer_t reducer_max = boost::bind(std::max<gain_t>, _1, _2);
+    std::vector<tuple_t> prop_to_reducer = boost::assign::tuple_list_of
+        (_gain_prop,      reducer_sum)(_gain_min_prop,  reducer_sum)
+        (_gain_max_prop,  reducer_sum)(_gain_step_prop, reducer_max);
+
+    /*!
+     * Handle getting overall gains when a name is not specified.
+     * For the gain props below, set the overall value and return true. 
+     */
+    BOOST_FOREACH(tuple_t p2r, prop_to_reducer){
+        if (_is_equal(key, p2r.get<0>())){
+            //form the gains vector from the props vector
+            prop_names_t prop_names = GET_PROP_NAMES();
+            std::vector<gain_t> gains(prop_names.size());
+            std::transform(
+                prop_names.begin(), prop_names.end(), gains.begin(),
+                boost::bind(get_named_gain, _wax_obj_ptr, p2r.get<0>(), _1)
+            );
+
+            //reduce across the gain vector
+            val = std::reduce<gain_t>(gains.begin(), gains.end(), p2r.get<1>());
+            return true;
+        }
+    }
+
+    return false;
+}
+
+bool gain_handler::intercept_set(const wax::type &key_, const wax::type &val){
+    _check_key(key_); //verify the key
+
+    wax::type key; std::string name;
+    tie(key, name) = extract_named_prop(key_);
+
+    /*!
+     * Verify that a named gain component is in range.
+     */
+    try{
+        //only handle the gain props
+        ASSERT_THROW(_is_equal(key, _gain_prop));
+
+        //check that the gain is in range
+        gain_t gain = wax::cast<gain_t>(val);
+        gain_t gain_min = get_named_gain(_wax_obj_ptr, _gain_min_prop,  name);
+        gain_t gain_max = get_named_gain(_wax_obj_ptr, _gain_max_prop,  name);
+        ASSERT_THROW(gain > gain_max or gain < gain_min);
+
+        //if we get here, throw an exception
+        throw std::range_error(str(
+            boost::format("gain %s is out of range of (%f, %f)") % name % gain_min % gain_max
+        ));
+    }
+    catch(const std::assert_error &){}
+
+    /*!
+     * Handle setting the overall gain.
+     */
+    if (_is_equal(key, _gain_prop) and name == ""){
+        gain_t gain = wax::cast<gain_t>(val);
+        prop_names_t prop_names = GET_PROP_NAMES();
+        BOOST_FOREACH(std::string name, prop_names){
+            //get the min, max, step for this gain name
+            gain_t gain_min  = get_named_gain(_wax_obj_ptr, _gain_min_prop,  name);
+            gain_t gain_max  = get_named_gain(_wax_obj_ptr, _gain_max_prop,  name);
+            gain_t gain_step = get_named_gain(_wax_obj_ptr, _gain_step_prop, name);
+
+            //clip g to be within the allowed range
+            gain_t g = std::min(std::max(gain, gain_min), gain_max);
+            //set g to be a multiple of the step size
+            g -= fmod(g, gain_step);
+            //set g to be the new gain
+            (*_wax_obj_ptr)[named_prop_t(_gain_prop, name)] = g;
+            //subtract g out of the total gain left to apply
+            gain -= g;
+        }
+        return true;
+    }
+
+    return false;
+}