fix copy constructor (Coverity) and SetFunction

git-svn-id: http://root.cern.ch/svn/root/trunk@44142 27541ba8-7e3a-0410-8455-c3a389f83636

math/mathcore/inc/Math/RichardsonDerivator.h

@@ -191,11 +191,11 @@ public:
       return Derivative3(x);
    }
 
-   /** Set function for derivative calculation (function is not copied in)
+   /** Set function for derivative calculation (copy the function if option has been enabled in the constructor)
 
        \@param f Function to be differentiated
    */
-   void SetFunction (const IGenFunction & f) { fFunction = &f; }
+   void SetFunction (const IGenFunction & f);
 
    /** Set step size for derivative calculation
 

math/mathcore/src/RichardsonDerivator.cxx

@@ -28,7 +28,7 @@ RichardsonDerivator::RichardsonDerivator(double h) :
    // Default Constructor.
 }
 RichardsonDerivator::RichardsonDerivator(const ROOT::Math::IGenFunction & f, double h, bool copyFunc) : 
-   fFunctionCopied(false),
+   fFunctionCopied(copyFunc),
    fStepSize(h),
    fLastError(0),
    fFunction(0)
@@ -38,6 +38,7 @@ RichardsonDerivator::RichardsonDerivator(const ROOT::Math::IGenFunction & f, dou
    else fFunction = &f;
 }
 
+
 RichardsonDerivator::~RichardsonDerivator()
 {
    // destructor
@@ -54,15 +55,24 @@ RichardsonDerivator::RichardsonDerivator(const RichardsonDerivator & rhs)
 RichardsonDerivator &  RichardsonDerivator::operator= ( const RichardsonDerivator & rhs) 
 {
    // Assignment operator
+   if (&rhs == this) return *this;
    fFunctionCopied = rhs.fFunctionCopied;
    fStepSize = rhs.fStepSize;
    fLastError = rhs.fLastError;
-   fFunction = rhs.fFunction;
-   if (fFunctionCopied && fFunction != 0) 
-      fFunction = fFunction->Clone();
+   SetFunction(*rhs.fFunction);
    return *this;
 }
 
+void RichardsonDerivator::SetFunction(const ROOT::Math::IGenFunction & f)
+{
+   // set function
+   if (fFunctionCopied) {
+      if (fFunction) delete fFunction;
+      fFunction = f.Clone(); 
+   }
+   else fFunction = &f;
+}
+
 double RichardsonDerivator::Derivative1 (double x)
 {
    const double kC1 = 1.E-15;