Factored Approx out into own file

include/internal/catch_approx.hpp

@@ -0,0 +1,88 @@
+/*
+ *  catch_approx.hpp
+ *  Catch
+ *
+ *  Created by Phil on 28/04/2011.
+ *  Copyright 2010 Two Blue Cubes Ltd. All rights reserved.
+ *
+ *  Distributed under the Boost Software License, Version 1.0. (See accompanying
+ *  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+ *
+ */
+#ifndef TWOBLUECUBES_CATCH_APPROX_HPP_INCLUDED
+#define TWOBLUECUBES_CATCH_APPROX_HPP_INCLUDED
+
+#include "catch_capture.hpp"
+
+#include <cmath>
+
+namespace Catch
+{
+    
+    // !TBD Need to clean this all up
+#define CATCH_absTol 1e-10
+#define CATCH_relTol 1e-10
+    
+    inline double catch_max( double x, double y )
+    {
+        return x > y ? x : y;
+    }
+    namespace Detail
+    {
+        class Approx
+        {
+        public:
+            ///////////////////////////////////////////////////////////////////////////
+            // !TBD more generic
+            explicit Approx
+            (
+             double d
+             )
+            : m_d( d )
+            {
+            }
+            
+            ///////////////////////////////////////////////////////////////////////////
+            template<typename T>
+            friend bool operator == 
+            (
+             const T& lhs, 
+             const Approx& rhs
+             )
+            {
+                // !TBD Use proper tolerance
+                // From: http://realtimecollisiondetection.net/blog/?p=89
+                // see also: http://www.cygnus-software.com/papers/comparingfloats/comparingfloats.htm
+                return fabs( lhs - rhs.m_d ) <= catch_max( CATCH_absTol, CATCH_relTol * catch_max( fabs(lhs), fabs(rhs.m_d) ) );
+            }
+            
+            ///////////////////////////////////////////////////////////////////////////
+            template<typename T>
+            friend bool operator != 
+            (
+             const T& lhs, 
+             const Approx& rhs
+             )
+            {
+                return ! operator==( lhs, rhs );
+            }
+            
+            double m_d;
+        };
+    }
+  
+    ///////////////////////////////////////////////////////////////////////////////
+    template<>
+    inline std::string toString<Detail::Approx>
+    (
+        const Detail::Approx& value
+    )
+    {
+        std::ostringstream oss;
+        oss << "Approx( " << value.m_d << ")";
+        return oss.str();
+    }
+    
+} // end namespace Catch
+
+#endif // TWOBLUECUBES_CATCH_APPROX_HPP_INCLUDED