even more efficient

code/FBXConverter.cpp

@@ -442,15 +442,17 @@ namespace Assimp {
         void FBXConverter::GetUniqueName(const std::string &name, std::string &uniqueName)
         {
             uniqueName = name;
-            int i = 0;
-            while (mNodeNames.find(uniqueName) != mNodeNames.end())
+            auto it_pair = mNodeNameInstances.insert({ name, 0 }); // duplicate node name instance count
+            unsigned int& i = it_pair.first->second;
+            auto uniqueIt_pair = mNodeNames.insert(uniqueName);
+            while (!uniqueIt_pair.second)
             {
                 i++;
                 std::stringstream ext;
                 ext << name << std::setfill('0') << std::setw(3) << i;
                 uniqueName = ext.str();
+                uniqueIt_pair = mNodeNames.insert(uniqueName);
             }
-            mNodeNames.insert(uniqueName);
         }
 
         const char* FBXConverter::NameTransformationComp(TransformationComp comp) {

code/FBXConverter.h

@@ -461,6 +461,10 @@ private:
     using NodeAnimBitMap = std::map<std::string, unsigned int> ;
     NodeAnimBitMap node_anim_chain_bits;
 
+    // number of nodes with the same name
+    using NodeAnimNameMap = std::unordered_map<std::string, unsigned int>;
+    NodeAnimNameMap mNodeNameInstances;
+
     using NodeNameCache = std::unordered_set<std::string>;
     NodeNameCache mNodeNames;
 

test/unit/utFBXImporterExporter.cpp

@@ -166,7 +166,7 @@ TEST_F(utFBXImporterExporter, importCubesComplexTransform) {
     ASSERT_STREQ(child1->mName.C_Str(), "Cube3");
 
     auto parent = child1;
-    constexpr size_t chain_length = 8u;
+    const size_t chain_length = 8u;
     const char* chainStr[chain_length] = {
         "Cube1001_$AssimpFbx$_Translation",
         "Cube1001_$AssimpFbx$_RotationPivot",