From c203321596a38502cb3008a3883805cb91d3535a Mon Sep 17 00:00:00 2001
From: Rainer Kuemmerle <rainer.kuemmerle@gmail.com>
Date: Sat, 25 Jan 2025 18:04:24 +0100
Subject: [PATCH] Apply minor syntax sugar

---
 g2o/core/abstract_graph.cpp            |  2 ++
 g2o/core/hyper_graph.h                 |  9 +++++----
 g2o/core/optimizable_graph.cpp         | 20 ++++++++------------
 unit_test/general/graph_operations.cpp | 11 ++++++++++-
 4 files changed, 25 insertions(+), 17 deletions(-)

diff --git a/g2o/core/abstract_graph.cpp b/g2o/core/abstract_graph.cpp
index fbf177405..9a4b1e47b 100644
--- a/g2o/core/abstract_graph.cpp
+++ b/g2o/core/abstract_graph.cpp
@@ -90,6 +90,8 @@ void AbstractGraph::clear() {
 
 void AbstractGraph::renameTags(
     const std::unordered_map<std::string, std::string>& tag_mapping) {
+  if (tag_mapping.empty()) return;
+
   auto map_tag = [&tag_mapping](const std::string& tag) {
     auto it = tag_mapping.find(tag);
     if (it == tag_mapping.end()) return tag;
diff --git a/g2o/core/hyper_graph.h b/g2o/core/hyper_graph.h
index b6e4b269f..db254d761 100644
--- a/g2o/core/hyper_graph.h
+++ b/g2o/core/hyper_graph.h
@@ -34,6 +34,7 @@
 #include <memory>
 #include <set>
 #include <unordered_map>
+#include <utility>
 #include <vector>
 
 #include "g2o_core_api.h"
@@ -153,7 +154,7 @@ class G2O_CORE_API HyperGraph {
     //! returns the set of hyper-edges that are leaving/entering in this vertex
     EdgeSetWeak& edges() { return edges_; }
     [[nodiscard]] HyperGraphElementType elementType() const final {
-      return kHgetVertex;
+      return HyperGraphElementType::kHgetVertex;
     }
 
    protected:
@@ -203,15 +204,15 @@ class G2O_CORE_API HyperGraph {
     /**
       set the ith vertex on the hyper-edge to the pointer supplied
       */
-    void setVertex(size_t i, const std::shared_ptr<Vertex>& v) {
+    void setVertex(size_t i, std::shared_ptr<Vertex> v) {
       assert(i < vertices_.size() && "index out of bounds");
-      vertices_[i] = v;
+      vertices_[i] = std::move(v);
     }
 
     [[nodiscard]] int id() const { return id_; }
     void setId(int id);
     [[nodiscard]] HyperGraphElementType elementType() const final {
-      return kHgetEdge;
+      return HyperGraphElementType::kHgetEdge;
     }
 
     [[nodiscard]] int numUndefinedVertices() const;
diff --git a/g2o/core/optimizable_graph.cpp b/g2o/core/optimizable_graph.cpp
index 491165fe7..f7efebc60 100644
--- a/g2o/core/optimizable_graph.cpp
+++ b/g2o/core/optimizable_graph.cpp
@@ -89,7 +89,7 @@ bool saveParameter(AbstractGraph& abstract_graph, Parameter* p) {
   if (tag.empty()) return false;
   std::vector<double> data;
   p->getParameterData(data);
-  abstract_graph.parameters().emplace_back(tag, p->id(), data);
+  abstract_graph.parameters().emplace_back(tag, p->id(), std::move(data));
   return true;
 }
 
@@ -108,8 +108,7 @@ void addDataToGraphElement(
     const std::vector<AbstractGraph::AbstractData>& data_vector) {
   Factory* factory = Factory::instance();
 
-  HyperGraph::GraphElemBitset elemDataBitset;
-  elemDataBitset[HyperGraph::kHgetData] = true;
+  const HyperGraph::GraphElemBitset elemDataBitset(1 << HyperGraph::kHgetData);
   for (const auto& abstract_data : data_vector) {
     const std::shared_ptr<HyperGraph::HyperGraphElement> element =
         factory->construct(abstract_data.tag, elemDataBitset);
@@ -355,13 +354,11 @@ bool OptimizableGraph::load(std::istream& is, io::Format format) {
     return false;
   }
 
-  if (!renamedTypesLookup_.empty()) {
-    abstract_graph.renameTags(renamedTypesLookup_);
-  }
+  abstract_graph.renameTags(renamedTypesLookup_);
 
   // Create the parameters of the graph
-  HyperGraph::GraphElemBitset elemParamBitset;
-  elemParamBitset[HyperGraph::kHgetParameter] = true;
+  const HyperGraph::GraphElemBitset elemParamBitset(
+      1 << HyperGraph::kHgetParameter);
   for (const auto& abstract_param : abstract_graph.parameters()) {
     const std::shared_ptr<HyperGraph::HyperGraphElement> pelement =
         factory->construct(abstract_param.tag, elemParamBitset);
@@ -384,8 +381,8 @@ bool OptimizableGraph::load(std::istream& is, io::Format format) {
   }
 
   // Create the vertices of the graph
-  HyperGraph::GraphElemBitset elemVertexBitset;
-  elemVertexBitset[HyperGraph::kHgetVertex] = true;
+  const HyperGraph::GraphElemBitset elemVertexBitset(
+      1 << HyperGraph::kHgetVertex);
   for (const auto& abstract_vertex : abstract_graph.vertices()) {
     const std::shared_ptr<HyperGraph::HyperGraphElement> graph_element =
         factory->construct(abstract_vertex.tag, elemVertexBitset);
@@ -411,8 +408,7 @@ bool OptimizableGraph::load(std::istream& is, io::Format format) {
   }
 
   // Create the edges of the graph
-  HyperGraph::GraphElemBitset elemEdgeBitset;
-  elemEdgeBitset[HyperGraph::kHgetEdge] = true;
+  const HyperGraph::GraphElemBitset elemEdgeBitset(1 << HyperGraph::kHgetEdge);
   for (const auto& abstract_edge : abstract_graph.edges()) {
     const std::shared_ptr<HyperGraph::HyperGraphElement> graph_element =
         factory->construct(abstract_edge.tag, elemEdgeBitset);
diff --git a/unit_test/general/graph_operations.cpp b/unit_test/general/graph_operations.cpp
index c7f417cce..1526be98f 100644
--- a/unit_test/general/graph_operations.cpp
+++ b/unit_test/general/graph_operations.cpp
@@ -51,7 +51,6 @@
 #include "g2o/types/slam3d/edge_se3_pointxyz.h"
 #include "g2o/types/slam3d/vertex_pointxyz.h"
 #include "g2o/types/slam3d/vertex_se3.h"
-#include "gmock/gmock.h"
 #include "unit_test/test_helper/allocate_optimizer.h"
 #include "unit_test/test_helper/eigen_matcher.h"
 
@@ -82,6 +81,16 @@ TEST(General, BinaryEdgeConstructor) {
   ASSERT_EQ(nullptr, e2.vertices()[1]);
 }
 
+TEST(General, GraphElemBitset) {
+  g2o::HyperGraph::GraphElemBitset elemParamBitset;
+  elemParamBitset[g2o::HyperGraph::kHgetParameter] = true;
+
+  const g2o::HyperGraph::GraphElemBitset elemParamFromInt(
+      1 << g2o::HyperGraph::kHgetParameter);
+
+  EXPECT_EQ(elemParamBitset, elemParamFromInt);
+}
+
 TEST(General, GraphAddVertex) {
   auto optimizer = g2o::internal::createOptimizerForTests();