remove const from functions returning by value

modules/core/include/opencv2/core/check.hpp

@@ -13,7 +13,7 @@ namespace cv {
 CV_EXPORTS const char* depthToString(int depth);
 
 /** Returns string of cv::Mat depth value: CV_8UC3 -> "CV_8UC3" or "<invalid type>" */
-CV_EXPORTS const String typeToString(int type);
+CV_EXPORTS String typeToString(int type);
 
 
 //! @cond IGNORED
@@ -23,7 +23,7 @@ namespace detail {
 CV_EXPORTS const char* depthToString_(int depth);
 
 /** Returns string of cv::Mat depth value: CV_8UC3 -> "CV_8UC3" or cv::String() */
-CV_EXPORTS const cv::String typeToString_(int type);
+CV_EXPORTS cv::String typeToString_(int type);
 
 enum TestOp {
   TEST_CUSTOM = 0,

modules/core/include/opencv2/core/utils/plugin_loader.private.hpp

@@ -147,7 +147,7 @@ public:
         return handle != NULL;
     }
     void* getSymbol(const char* symbolName) const;
-    const std::string getName() const;
+    std::string getName() const;
 private:
     void libraryLoad(const FileSystemPath_t& filename);
     void libraryRelease();

modules/core/src/check.cpp

@@ -14,7 +14,7 @@ const char* depthToString(int depth)
     return s ? s : "<invalid depth>";
 }
 
-const cv::String typeToString(int type)
+cv::String typeToString(int type)
 {
     cv::String s = detail::typeToString_(type);
     if (s.empty())
@@ -47,7 +47,7 @@ const char* depthToString_(int depth)
     return (depth <= CV_16F && depth >= 0) ? depthNames[depth] : NULL;
 }
 
-const cv::String typeToString_(int type)
+cv::String typeToString_(int type)
 {
     int depth = CV_MAT_DEPTH(type);
     int cn = CV_MAT_CN(type);

modules/core/src/ocl.cpp

@@ -231,7 +231,7 @@ static const bool CV_OPENCL_DISABLE_BUFFER_RECT_OPERATIONS = utils::getConfigura
 #endif
 );
 
-static const String getBuildExtraOptions()
+static String getBuildExtraOptions()
 {
     static String param_buildExtraOptions;
     static bool initialized = false;

modules/core/src/utils/plugin_loader.impl.hpp

@@ -56,7 +56,7 @@ void* DynamicLib::getSymbol(const char* symbolName) const
     return res;
 }
 
-const std::string DynamicLib::getName() const
+std::string DynamicLib::getName() const
 {
     return toPrintablePath(fname);
 }

modules/dnn/src/onnx/onnx_importer.cpp

@@ -205,7 +205,7 @@ private:
         bool param = utils::getConfigurationParameterBool("OPENCV_DNN_ONNX_USE_LEGACY_NAMES", false);
         return param;
     }
-    const std::string extractNodeName(const opencv_onnx::NodeProto& node_proto);
+    std::string extractNodeName(const opencv_onnx::NodeProto& node_proto);
 };
 
 
@@ -922,7 +922,7 @@ const ONNXImporter::DispatchMap& ONNXImporter::getDispatchMap(const opencv_onnx:
     return it->second;
 }
 
-const std::string ONNXImporter::extractNodeName(const opencv_onnx::NodeProto& node_proto)
+std::string ONNXImporter::extractNodeName(const opencv_onnx::NodeProto& node_proto)
 {
     // We need to rework DNN outputs API, this is a workaround for #21698
     if (node_proto.has_name() && !node_proto.name().empty())

modules/dnn/src/tensorflow/tf_importer.cpp

@@ -568,7 +568,7 @@ private:
     typedef std::map<std::string, TFImporterNodeParser> DispatchMap;
 
     const DispatchMap dispatch;
-    static const DispatchMap buildDispatchMap();
+    static DispatchMap buildDispatchMap();
 
     void parseConvolution        (tensorflow::GraphDef& net, const tensorflow::NodeDef& layer, LayerParams& layerParams);
     void parseBias               (tensorflow::GraphDef& net, const tensorflow::NodeDef& layer, LayerParams& layerParams);
@@ -645,7 +645,7 @@ protected:
     TFImporter* importer;
 };
 
-const TFImporter::DispatchMap TFImporter::buildDispatchMap()
+TFImporter::DispatchMap TFImporter::buildDispatchMap()
 {
     static DispatchMap dispatch;
     dispatch["Conv2D"] = dispatch["SpaceToBatchND"] = dispatch["DepthwiseConv2dNative"] =

modules/features2d/include/opencv2/features2d.hpp

@@ -1143,8 +1143,8 @@ protected:
         virtual void clear();
 
         const Mat& getDescriptors() const;
-        const Mat getDescriptor( int imgIdx, int localDescIdx ) const;
-        const Mat getDescriptor( int globalDescIdx ) const;
+        Mat getDescriptor( int imgIdx, int localDescIdx ) const;
+        Mat getDescriptor( int globalDescIdx ) const;
         void getLocalIdx( int globalDescIdx, int& imgIdx, int& localDescIdx ) const;
 
         int size() const;

modules/features2d/src/matchers.cpp

@@ -475,7 +475,7 @@ void DescriptorMatcher::DescriptorCollection::clear()
     mergedDescriptors.release();
 }
 
-const Mat DescriptorMatcher::DescriptorCollection::getDescriptor( int imgIdx, int localDescIdx ) const
+Mat DescriptorMatcher::DescriptorCollection::getDescriptor( int imgIdx, int localDescIdx ) const
 {
     CV_Assert( imgIdx < (int)startIdxs.size() );
     int globalIdx = startIdxs[imgIdx] + localDescIdx;
@@ -489,7 +489,7 @@ const Mat& DescriptorMatcher::DescriptorCollection::getDescriptors() const
     return mergedDescriptors;
 }
 
-const Mat DescriptorMatcher::DescriptorCollection::getDescriptor( int globalDescIdx ) const
+Mat DescriptorMatcher::DescriptorCollection::getDescriptor( int globalDescIdx ) const
 {
     CV_Assert( globalDescIdx < size() );
     return mergedDescriptors.row( globalDescIdx );

modules/gapi/include/opencv2/gapi/fluid/gfluidkernel.hpp

@@ -181,7 +181,7 @@ template<> struct fluid_get_in<cv::GMat>
 template<> struct fluid_get_in<cv::GScalar>
 {
     // FIXME: change to return by reference when moved to own::Scalar
-    static const cv::Scalar get(const cv::GArgs &in_args, int idx)
+    static cv::Scalar get(const cv::GArgs &in_args, int idx)
     {
         return in_args[idx].unsafe_get<cv::Scalar>();
     }

modules/gapi/include/opencv2/gapi/own/types.hpp

@@ -89,7 +89,7 @@ inline Rect& operator&=(Rect& lhs, const Rect& rhs)
     return lhs;
 }
 
-inline const Rect operator&(const Rect& lhs, const Rect& rhs)
+inline Rect operator&(const Rect& lhs, const Rect& rhs)
 {
     Rect result = lhs;
     return result &= rhs;

modules/stitching/include/opencv2/stitching.hpp

@@ -205,12 +205,12 @@ public:
     void setWaveCorrectKind(detail::WaveCorrectKind kind) { wave_correct_kind_ = kind; }
 
     Ptr<Feature2D> featuresFinder() { return features_finder_; }
-    const Ptr<Feature2D> featuresFinder() const { return features_finder_; }
+    Ptr<Feature2D> featuresFinder() const { return features_finder_; }
     void setFeaturesFinder(Ptr<Feature2D> features_finder)
         { features_finder_ = features_finder; }
 
     Ptr<detail::FeaturesMatcher> featuresMatcher() { return features_matcher_; }
-    const Ptr<detail::FeaturesMatcher> featuresMatcher() const { return features_matcher_; }
+    Ptr<detail::FeaturesMatcher> featuresMatcher() const { return features_matcher_; }
     void setFeaturesMatcher(Ptr<detail::FeaturesMatcher> features_matcher)
         { features_matcher_ = features_matcher; }
 

modules/stitching/include/opencv2/stitching/detail/motion_estimators.hpp

@@ -133,7 +133,7 @@ private:
 class CV_EXPORTS_W BundleAdjusterBase : public Estimator
 {
 public:
-    CV_WRAP const Mat refinementMask() const { return refinement_mask_.clone(); }
+    CV_WRAP Mat refinementMask() const { return refinement_mask_.clone(); }
     CV_WRAP void setRefinementMask(const Mat &mask)
     {
         CV_Assert(mask.type() == CV_8U && mask.size() == Size(3, 3));