Provides unit structure definitions and supports XML content parsing…

… for these units. (#156)

Co-authored-by: Wenweil1 <[email protected]>

include/fmi4cpp/fmi2/xml/model_description.hpp

@@ -6,6 +6,7 @@
 #include <fmi4cpp/fmi2/xml/fmu_attributes.hpp>
 #include <fmi4cpp/fmi2/xml/model_structure.hpp>
 #include <fmi4cpp/fmi2/xml/model_variables.hpp>
+#include <fmi4cpp/fmi2/xml/unit_definitions.hpp>
 
 #include <memory>
 #include <optional>
@@ -33,6 +34,7 @@ struct model_description_base
     std::shared_ptr<const fmi2::model_structure> model_structure;
 
     std::optional<fmi2::default_experiment> default_experiment;
+    std::optional<fmi2::unit_definitions> unit_definitions;
 
     size_t number_of_event_indicators;
     [[nodiscard]] size_t number_of_continuous_states() const;

include/fmi4cpp/fmi2/xml/unit_definitions.hpp

@@ -0,0 +1,54 @@
+/*
+ * File Name:    unit_definitions.h
+ * Description:  Defines structures for handling physical units and their conversions, including base units, display units, and unit definitions.
+ * Author:       weilong.wen
+ * Email:       [email protected]
+ * Created:     2025-02-03
+ */
+
+#ifndef FMI4CPP_UNITDEFINITIONS_HPP
+#define FMI4CPP_UNITDEFINITIONS_HPP
+
+#include <optional>
+#include <string>
+#include <vector>
+
+namespace fmi4cpp::fmi2
+{
+
+struct base_unit
+{
+    std::optional<int> kg = 0;
+    std::optional<int> m = 0;
+    std::optional<int> s = 0;
+    std::optional<int> A = 0;
+    std::optional<int> K = 0;
+    std::optional<int> mol = 0;
+    std::optional<int> cd = 0;
+    std::optional<int> rad = 0;
+    std::optional<double> factor = 1.0;
+    std::optional<double> offset = 0.0;
+};
+
+struct display_unit
+{
+    std::string name;
+    double factor = 1.0;
+    double offset = 0.0;
+};
+
+struct unit
+{
+    std::string name;
+    base_unit base_unit;
+    std::vector<display_unit> display_units;
+};
+
+struct unit_definitions
+{
+    std::vector<unit> units;
+};
+
+} // namespace fmi4cpp::fmi2
+
+#endif // FMI4CPP_UNITDEFINITIONS_HPP

src/CMakeLists.txt

@@ -33,6 +33,7 @@ set(publicHeaders
 
     "fmi4cpp/fmi2/xml/enums.hpp"
     "fmi4cpp/fmi2/xml/source_files.hpp"
+    "fmi4cpp/fmi2/xml/unit_definitions.hpp"
 
     "fmi4cpp/fmi2/xml/default_experiment.hpp"
     "fmi4cpp/fmi2/xml/fmu_attributes.hpp"

src/fmi4cpp/fmi2/xml/model_description_parser.cpp

@@ -148,6 +148,59 @@ std::unique_ptr<const model_structure> parse_model_structure(const pugi::xml_nod
     return std::make_unique<const model_structure>(outputs, derivatives, initial_unknowns);
 }
 
+base_unit parse_base_unit(const pugi::xml_node& node)
+{
+    base_unit baseUnit;
+    baseUnit.kg = parse_attribute<int>(node, "kg");
+    baseUnit.m = parse_attribute<int>(node, "m");
+    baseUnit.s = parse_attribute<int>(node, "s");
+    baseUnit.A = parse_attribute<int>(node, "A");
+    baseUnit.K = parse_attribute<int>(node, "K");
+    baseUnit.mol = parse_attribute<int>(node, "mol");
+    baseUnit.cd = parse_attribute<int>(node, "cd");
+    baseUnit.rad = parse_attribute<int>(node, "rad");
+    baseUnit.factor = parse_attribute<double>(node, "factor");
+    baseUnit.offset = parse_attribute<double>(node, "offset");
+
+    return baseUnit;
+}
+
+display_unit parse_display_unit(const pugi::xml_node& node)
+{
+    display_unit displayUnit;
+    displayUnit.name = parse_attribute<std::string>(node, "name");
+    displayUnit.factor = parse_attribute<double>(node, "factor");
+    displayUnit.offset = parse_attribute<double>(node, "offset");
+
+    return displayUnit;
+}
+
+unit parse_unit(const pugi::xml_node& node)
+{
+    unit Unit;
+    for (const pugi::xml_node& v : node) {
+        if (std::string("BaseUnit") == v.name()) {
+            Unit.base_unit = parse_base_unit(v);
+        } else if (std::string("DisplayUnit") == v.name()) {
+            Unit.display_units.push_back(parse_display_unit(v));
+        }
+    }
+    Unit.name = parse_attribute<std::string>(node, "name");
+
+    return Unit;
+}
+
+unit_definitions parse_unit_definitions(const pugi::xml_node& node)
+{
+    unit_definitions unitDefs;
+    for (const pugi::xml_node& v : node) {
+        if (std::string("Unit") == v.name()) {
+            unitDefs.units.push_back(parse_unit(v));
+        }
+    }
+    return unitDefs;
+}
+
 fmu_attributes parse_fmu_attributes(const pugi::xml_node& node)
 {
 
@@ -322,6 +375,8 @@ std::unique_ptr<const model_description> fmi4cpp::fmi2::parse_model_description(
             base.model_variables = std::move(parse_model_variables(v));
         } else if (std::string("ModelStructure") == v.name()) {
             base.model_structure = std::move(parse_model_structure(v));
+        } else if (std::string("UnitDefinitions") == v.name()) {
+            base.unit_definitions = std::move(parse_unit_definitions(v));
         }
     }