Improving hash for log once instances

nadrino · Apr 7, 2023 · b00922b · b00922b
1 parent c592711
commit b00922b
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Showing 3 changed files with 13 additions and 4 deletions.
diff --git a/include/Logger.h b/include/Logger.h
@@ -184,14 +184,14 @@ namespace {
     static inline std::string _currentPrefix_{};
     static inline std::string _outputFileName_{};
     static inline std::mutex _loggerMutex_{};
-    static inline std::unordered_set<void*> _onceLogList_{};
+    static inline std::unordered_set<size_t> _onceLogList_{};
     static inline Color _currentColor_{Logger::Color::RESET};
     static inline LogLevel _currentLogLevel_{Logger::LogLevel::TRACE};
     static inline LoggerUtils::StreamBufferSupervisor* _streamBufferSupervisorPtr_{nullptr};
     static inline LoggerUtils::StreamBufferSupervisor _streamBufferSupervisor_;
 
     // non-static
-    std::scoped_lock<std::mutex> _lock_{_loggerMutex_};
+    std::scoped_lock<std::mutex> _lock_{_loggerMutex_}; // one logger can be created at a given time
 #else
     // parameters
     static bool _enableColors_;

diff --git a/include/implementation/Logger.impl.h b/include/implementation/Logger.impl.h
@@ -209,14 +209,16 @@ namespace {
     _currentLineNumber_ = lineNumber_;
 
     if( once_ ){
-      if( _onceLogList_.find( reinterpret_cast<int *>( (int*) fileName_ - (int*) &lineNumber_ ) ) != _onceLogList_.end() ){
+      size_t instanceHash{(size_t) lineNumber_};
+      LoggerUtils::hashCombine(instanceHash, fileName_);
+      if( _onceLogList_.find( instanceHash ) != _onceLogList_.end() ){
         // mute
         Logger::_currentLogLevel_ = LogLevel::INVALID;
       }
       else{
         // will be printed only this time:
         // dirty trick (better way??): get unique identifier out of file name and lineNumber.
-        _onceLogList_.insert(reinterpret_cast<int *>( (int*) fileName_ - (int*) &lineNumber_ ) );
+        _onceLogList_.insert( instanceHash );
       }
     }
   }

diff --git a/include/implementation/LoggerUtils.h b/include/implementation/LoggerUtils.h
@@ -10,6 +10,7 @@
 #include "thread"
 #include "vector"
 #include "string"
+#include "functional"
 
 
 #ifndef HAS_CPP_17
@@ -95,6 +96,12 @@ namespace LoggerUtils{
   inline int getTerminalWidth();
   inline std::string getExecutableName();
 
+  // hash Utils
+  template <class T> inline void hashCombine(std::size_t& seed, const T& v) {
+    std::hash<T> hasher;
+    seed ^= hasher(v) + 0x9e3779b9 + (seed<<6) + (seed>>2);
+  }
+
 }
 
 #include "LoggerUtils.impl.h"