Support for unit conversions with multiple factors

CMakeLists.txt

@@ -2,7 +2,7 @@
 set(AGENT_VERSION_MAJOR 2)
 set(AGENT_VERSION_MINOR 5)
 set(AGENT_VERSION_PATCH 0)
-set(AGENT_VERSION_BUILD 2)
+set(AGENT_VERSION_BUILD 3)
 set(AGENT_VERSION_RC "")
 
 # This minimum version is to support Visual Studio 2019 and C++ feature checking and FetchContent

src/mtconnect/device_model/data_item/unit_conversion.cpp

@@ -171,17 +171,31 @@ namespace mtconnect::device_model::data_item {
 
       factor = sscale / tscale;
 
-      key = source;
-      key = key.append("-").append(target);
+      vector<string> sunits;
+      boost::split(sunits, source, boost::is_any_of("_"));
 
-      const auto &conversion = m_conversions.find(string(key));
-      // Check for no support units and not power or factor scaling.
-      if (conversion == m_conversions.end() && factor == 1.0)
-        return nullptr;
-      else if (conversion != m_conversions.end())
+      vector<string> tunits;
+      boost::split(tunits, target, boost::is_any_of("_"));
+
+      if (sunits.size() == tunits.size())
       {
-        factor *= conversion->second.factor();
-        offset = conversion->second.offset();
+        for (auto si = sunits.begin(), ti = tunits.begin();
+             si != sunits.end() && ti != tunits.end(); si++, ti++)
+        {
+          key = *si;
+          key = key.append("-").append(*ti);
+
+          const auto &conversion = m_conversions.find(string(key));
+
+          // Check for no support units and not power or factor scaling.
+          if (conversion == m_conversions.end() && factor == 1.0)
+            return nullptr;
+          else if (conversion != m_conversions.end())
+          {
+            factor *= conversion->second.factor();
+            offset = conversion->second.offset();
+          }
+        }
       }
 
       if (tpower != 1.0)

src/mtconnect/entity/xml_parser.cpp

@@ -123,7 +123,6 @@ namespace mtconnect::entity {
           }
         }
 
-        /// TODO: Add support for tables
         DataSetValue value;
         auto valueNode = child->children;
         if (valueNode)

test_package/unit_conversion_test.cpp

@@ -142,4 +142,8 @@ TEST(UnitConversionTest, check_conversion_from_kw_h_to_watt_second)
   auto conv = UnitConversion::make("KILOWATT/HOUR", "WATT/SECOND");
   EXPECT_NEAR(0.16666, conv->convert(0.6), 0.001);
   EXPECT_NEAR(0.25556, conv->convert(0.92), 0.001);
+
+  conv = UnitConversion::make("KILOWATT_HOUR", "WATT_SECOND");
+  EXPECT_NEAR(2160000.0, conv->convert(0.6), 0.001);
+  EXPECT_NEAR(3312000.0, conv->convert(0.92), 0.001);
 }