[PropertyHelper] Use epsilon for float numbers comparison

include/yat4tango/PropertyHelper.hpp

@@ -28,14 +28,12 @@
 // DEPENDENCIES
 // ============================================================================
 #include <iostream>
+#include <limits>
 #include <yat/threading/Mutex.h>
 
 namespace yat4tango
 {
 
-#define FLOAT_PRECISION float(1e-8)
-#define DOUBLE_PRECISION double(1e-15)
-
 //-------------------------------------------------------------------------
 // Comparison functors specialization for floatting point numbers
 //-------------------------------------------------------------------------
@@ -44,7 +42,7 @@ struct PropertyHelper::ValueComp<float>
 {
   bool operator()(const float& v1, const float& v2)
   {
-    return yat::fp_is_equal(v1, v2, FLOAT_PRECISION);
+    return yat::fp_is_equal(v1, v2, std::numeric_limits<float>::epsilon());
   }
 };
 
@@ -53,7 +51,7 @@ struct PropertyHelper::ValueComp<double>
 {
   bool operator()(const double& v1, const double& v2)
   {
-    return yat::fp_is_equal(v1, v2, DOUBLE_PRECISION);
+    return yat::fp_is_equal(v1, v2, std::numeric_limits<double>::epsilon());
   }
 };
 
@@ -67,7 +65,7 @@ struct PropertyHelper::ValueComp< std::vector<float> >
 
     for( std::size_t i = 0; i < v1.size(); ++i )
     {
-      if( !yat::fp_is_equal(v1[i], v2[i], FLOAT_PRECISION) )
+      if( !yat::fp_is_equal(v1[i], v2[i], std::numeric_limits<float>::epsilon()) )
         return false;
     }
     return true;
@@ -84,7 +82,7 @@ struct PropertyHelper::ValueComp< std::vector<double> >
 
     for( std::size_t i = 0; i < v1.size(); ++i )
     {
-      if( !yat::fp_is_equal(v1[i], v2[i], DOUBLE_PRECISION) )
+      if( !yat::fp_is_equal(v1[i], v2[i], std::numeric_limits<double>::epsilon()) )
         return false;
     }
     return true;
@@ -115,11 +113,10 @@ bool PropertyHelper::value_cache(Tango::DeviceImpl* dev_p,
   else
   {
     MapIterator it;
+    T last_val;
     {
       yat::AutoMutex<> lock(s_mtx);
       it = (*values_cache_p).find(key);
-    }
-    T last_val;
       if( (*values_cache_p).end() == it )
       {
         // Value not cached yet
@@ -127,6 +124,7 @@ bool PropertyHelper::value_cache(Tango::DeviceImpl* dev_p,
       }
       else
         last_val = it->second;
+    }
 
     if( PropertyHelper::ValueComp<T>()(last_val, val) )
       return false;