ENH: Moving static InverseValue and SignOfValue functions to otbMath.h following code review

Code/BasicFilters/otbMaximumAutocorrelationFactorImageFilter.h

@@ -141,22 +141,6 @@ private:
   MaximumAutocorrelationFactorImageFilter(const Self &); //purposely not implemented
   void operator =(const Self&); //purposely not implemented
 
-  static RealType InverseValue(const RealType & value)
-  {
-    if(value != 0)
-      return 1/value;
-    else
-      return 0.; // ugly
-  }
-
-  static RealType SignOfValue(const RealType & value)
-  {
-    if(value==0)
-      return value;
-    else
-      return (value > 0 ? 1. : -1.);
-  }
-
   /** The covariance estimator for the image */
   CovarianceEstimatorPointer m_CovarianceEstimator;
 

Code/BasicFilters/otbMaximumAutocorrelationFactorImageFilter.txx

@@ -20,6 +20,7 @@
 
 #include "otbMaximumAutocorrelationFactorImageFilter.h"
 #include "otbMultiChannelExtractROI.h"
+#include "otbMath.h"
 #include "itkSubtractImageFilter.h"
 
 #include "vnl/algo/vnl_matrix_inverse.h"

Code/ChangeDetection/otbMultivariateAlterationDetectorImageFilter.h

@@ -155,22 +155,6 @@ private:
   MultivariateAlterationDetectorImageFilter(const Self &); //purposely not implemented
   void operator =(const Self&); //purposely not implemented
 
-  static RealType InverseValue(const RealType & value)
-  {
-    if(value != 0)
-      return 1/value;
-    else
-      return 0.; // ugly
-  }
-  
-  static RealType SignOfValue(const RealType & value)
-  {
-    if(value==0)
-      return value;
-    else
-      return (value > 0 ? 1. : -1.);
-  }
-
   CovarianceEstimatorPointer m_CovarianceEstimator;
   MatrixType                 m_CovarianceMatrix;
   VectorType                 m_MeanValues;

Code/ChangeDetection/otbMultivariateAlterationDetectorImageFilter.txx

@@ -19,6 +19,7 @@
 #define __otbMultivariateAlterationDetectorImageFilter_txx
 
 #include "otbMultivariateAlterationDetectorImageFilter.h"
+#include "otbMath.h"
 
 #include "vnl/algo/vnl_matrix_inverse.h"
 #include "vnl/algo/vnl_generalized_eigensystem.h"

Code/Common/otbMath.h

@@ -85,6 +85,16 @@ const long double CONST_SQRT1_2l =  0.7071067811865475244008443621048490L;  /* 1
 const long double CONST_SQRT3l =    1.7320508075688772935274463415058724L;  /* sqrt(3) */
 const long double CONST_EULERl =    0.5772156649015328606065120900824024L;  /* euler constant*/
 
+template <typename T> T InverseValue(const T & value)
+{
+  return ((value > 0 || value > 0) ? 1/value : 0);
+}
+
+template <typename T> T SignOfValue(const T & value)
+{
+  return (value > 0) ? 1 : ((value < 0) ? -1 : 0);
+}
+
 #endif
 
 }