Merge pull request #3967 from stweil/coverity

Fix a number of performance issues (reported by Coverity Scan)

Author: zdenop

src/api/hocrrenderer.cpp

@@ -412,7 +412,7 @@ char *TessBaseAPI::GetHOCRText(ETEXT_DESC *monitor, int page_number) {
                    << " id='"
                    << "timestep" << page_id << "_" << wcnt << "_" << tcnt
                    << "'>";
-          for (auto conf : timestep) {
+          for (auto &&conf : timestep) {
             hocr_str << "\n         <span class='ocrx_cinfo'"
                      << " id='"
                      << "choice_" << page_id << "_" << wcnt << "_" << ccnt

src/ccmain/control.cpp

@@ -1191,7 +1191,7 @@ bool Tesseract::SelectGoodDiacriticOutlines(int pass, float certainty_threshold,
     *ok_outlines = best_outlines;
     if (debug_noise_removal) {
       tprintf("%s noise combination ", blob ? "Adding" : "New");
-      for (auto best_outline : best_outlines) {
+      for (auto &&best_outline : best_outlines) {
         tprintf("%c", best_outline ? 'T' : 'F');
       }
       tprintf(" yields certainty %g, beating target of %g\n", best_cert, target_cert);

src/ccstruct/fontinfo.cpp

@@ -67,7 +67,7 @@ bool FontInfoTable::DeSerialize(TFile *fp) {
 bool FontInfoTable::SetContainsFontProperties(int font_id,
                                               const std::vector<ScoredFont> &font_set) const {
   uint32_t properties = at(font_id).properties;
-  for (auto f : font_set) {
+  for (auto &&f : font_set) {
     if (at(f.fontinfo_id).properties == properties) {
       return true;
     }

src/ccstruct/points.h

@@ -269,11 +269,11 @@ class TESS_API FCOORD {
   bool normalise();
 
   /// test equality
-  bool operator==(const FCOORD &other) {
+  bool operator==(const FCOORD &other) const {
     return xcoord == other.xcoord && ycoord == other.ycoord;
   }
   /// test inequality
-  bool operator!=(const FCOORD &other) {
+  bool operator!=(const FCOORD &other) const {
     return xcoord != other.xcoord || ycoord != other.ycoord;
   }
   /// rotate 90 deg anti

src/ccutil/params.h

@@ -253,7 +253,7 @@ class StringParam : public Param {
   bool empty() const {
     return value_.empty();
   }
-  bool operator==(const std::string &other) {
+  bool operator==(const std::string &other) const {
     return value_ == other;
   }
   void operator=(const std::string &value) {

src/ccutil/serialis.h

@@ -157,7 +157,7 @@ class TESS_API TFile {
       return false;
     } else if constexpr (std::is_same<T, std::string>::value) {
       // Serialize strings.
-      for (auto string : data) {
+      for (auto &&string : data) {
         if (!Serialize(string)) {
           return false;
         }

src/classify/adaptmatch.cpp

@@ -1079,7 +1079,7 @@ void Classify::MasterMatcher(INT_TEMPLATES_STRUCT *templates, int16_t num_featur
   int top = blob_box.top();
   int bottom = blob_box.bottom();
   UnicharRating int_result;
-  for (auto result : results) {
+  for (auto &&result : results) {
     CLASS_ID class_id = result.Class;
     BIT_VECTOR protos = classes != nullptr ? classes[class_id]->PermProtos : AllProtosOn;
     BIT_VECTOR configs = classes != nullptr ? classes[class_id]->PermConfigs : AllConfigsOn;

src/classify/shapeclassifier.cpp

@@ -174,7 +174,7 @@ void ShapeClassifier::UnicharPrintResults(const char *context,
             GetUnicharset().id_to_unichar(result.unichar_id));
     if (!result.fonts.empty()) {
       tprintf(" Font Vector:");
-      for (auto font : result.fonts) {
+      for (auto &&font : result.fonts) {
         tprintf(" %d", font.fontinfo_id);
       }
     }

src/dict/dawg.h

@@ -361,7 +361,7 @@ struct DawgPosition {
         dawg_index(dawg_idx),
         punc_index(punc_idx),
         back_to_punc(backtopunc) {}
-  bool operator==(const DawgPosition &other) {
+  bool operator==(const DawgPosition &other) const {
     return dawg_index == other.dawg_index && dawg_ref == other.dawg_ref &&
            punc_index == other.punc_index && punc_ref == other.punc_ref &&
            back_to_punc == other.back_to_punc;
@@ -382,7 +382,7 @@ class DawgPositionVector : public std::vector<DawgPosition> {
   /// true otherwise.
   inline bool add_unique(const DawgPosition &new_pos, bool debug,
                          const char *debug_msg) {
-    for (auto position : *this) {
+    for (auto &&position : *this) {
       if (position == new_pos) {
         return false;
       }

src/lstm/networkio.cpp

@@ -173,7 +173,7 @@ void NetworkIO::FromPixes(const StaticShape &shape, const std::vector<Image> &pi
   int target_height = shape.height();
   int target_width = shape.width();
   std::vector<std::pair<int, int>> h_w_pairs;
-  for (auto pix : pixes) {
+  for (auto &&pix : pixes) {
     Image var_pix = pix;
     int width = pixGetWidth(var_pix);
     if (target_width != 0) {