Export NGT Property to C API and add struct and function to get it

lib/NGT/Capi.cpp

@@ -395,6 +395,70 @@ bool ngt_set_property_distance_type_inner_product(NGTProperty prop, NGTError err
   return ngt_set_property_distance_type(prop, NGT::Index::Property::DistanceType::DistanceTypeInnerProduct, error);
 }
 
+NGTPropertyInfo ngt_get_property_info(NGTIndex index, NGTError error) {
+  NGT::Property prop;
+  try {
+    static_cast<NGT::Index*>(index)->getProperty(prop);
+  } catch(std::exception &err) {
+    std::stringstream ss;
+    ss << "Capi : " << __FUNCTION__ << "() : Error: " << err.what();
+    operate_error_string_(ss, error);
+    NGTPropertyInfo err_val = {0};
+    return err_val;
+  }
+  NGTPropertyInfo info = {
+    prop.dimension,
+    prop.threadPoolSize,
+    prop.objectType,
+    prop.distanceType,
+    prop.indexType,
+    prop.databaseType,
+    prop.objectAlignment,
+    prop.pathAdjustmentInterval,
+#ifdef NGT_SHARED_MEMORY_ALLOCATOR
+    prop.graphSharedMemorySize,
+    prop.treeSharedMemorySize,
+    prop.objectSharedMemorySize,
+#else
+    -1,
+    -1,
+    -1,
+#endif
+    prop.prefetchOffset,
+    prop.prefetchSize,
+    prop.accuracyTable.c_str(),
+    prop.searchType.c_str(),
+#ifdef NGT_INNER_PRODUCT
+    prop.maxMagnitude,
+#else
+    -1,
+#endif
+    prop.nOfNeighborsForInsertionOrder,
+    prop.epsilonForInsertionOrder,
+#ifdef NGT_REFINEMENT
+    prop.refinementObjectType,
+#else
+    -1,
+#endif
+    prop.truncationThreshold,
+    prop.edgeSizeForCreation,
+    prop.edgeSizeForSearch,
+    prop.edgeSizeLimitForCreation,
+    prop.insertionRadiusCoefficient,
+    prop.seedSize,
+    prop.seedType,
+    prop.truncationThreadPoolSize,
+    prop.batchSizeForCreation,
+    prop.graphType,
+    prop.dynamicEdgeSizeBase,
+    prop.dynamicEdgeSizeRate,
+    prop.buildTimeLimit,
+    prop.outgoingEdge,
+    prop.incomingEdge
+  };
+  return info;
+}
+
 NGTObjectDistances ngt_create_empty_results(NGTError error) {
   try{
     return static_cast<NGTObjectDistances>(new NGT::ObjectDistances());

lib/NGT/Capi.h

@@ -119,6 +119,43 @@ typedef struct {
   size_t indegreeHistogramSize;
 } NGTGraphStatistics;
 
+typedef struct {
+  int dimension;
+  int thread_pool_size;
+  int object_type;
+  int distance_type;
+  int index_type;
+  int database_type;
+  int object_alignment;
+  int path_adjustment_interval;
+  int graph_shared_memory_size;
+  int tree_shared_memory_size;
+  int object_shared_memory_size;
+  int prefetch_offset;
+  int prefetch_size;
+  const char* accuracy_table;
+  const char* search_type;
+  float max_magnitude;
+  int n_of_neighbors_for_insertion_order;
+  float epsilon_for_insertion_order;
+  int refinement_object_type;
+  int16_t truncation_threshold;
+  int16_t edge_size_for_creation;
+  int16_t edge_size_for_search;
+  int16_t edge_size_limit_for_creation;
+  double insertion_radius_coefficient;
+  int16_t seed_size;
+  int seed_type;
+  int16_t truncation_thread_pool_size;
+  int16_t batch_size_for_creation;
+  int graph_type;
+  int16_t dynamic_edge_size_base;
+  int16_t dynamic_edge_size_rate;
+  float build_time_limit;
+  int16_t outgoing_edge;
+  int16_t incoming_edge;
+} NGTPropertyInfo;
+
 NGTIndex ngt_open_index(const char *, NGTError);
 
 NGTIndex ngt_open_index_as_read_only(const char *, NGTError);
@@ -185,6 +222,8 @@ bool ngt_set_property_distance_type_normalized_cosine(NGTProperty, NGTError);
 
 bool ngt_set_property_distance_type_inner_product(NGTProperty, NGTError);
 
+NGTPropertyInfo ngt_get_property_info(NGTIndex, NGTError);
+
 NGTObjectDistances ngt_create_empty_results(NGTError);
 
 bool ngt_search_index(NGTIndex, double*, int32_t, size_t, float, float, NGTObjectDistances, NGTError);