From e0a34e1dc83a684c4152460560ae1af1c32a832b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?S=C3=A9bastien=20Loriot?= <sloriot.ml@gmail.com>
Date: Mon, 15 Oct 2012 07:39:24 +0000
Subject: [PATCH] adding a specialization for Sqrt_extension for NT_converter
 and its test

---
 .../CGAL/Sqrt_extension/Sqrt_extension_type.h | 43 +++++++++++++++++++
 .../test/Number_types/Sqrt_extension.cpp      | 18 +++++++-
 2 files changed, 59 insertions(+), 2 deletions(-)

diff --git a/Number_types/include/CGAL/Sqrt_extension/Sqrt_extension_type.h b/Number_types/include/CGAL/Sqrt_extension/Sqrt_extension_type.h
index e5c5ec41246..f4ed07f7742 100644
--- a/Number_types/include/CGAL/Sqrt_extension/Sqrt_extension_type.h
+++ b/Number_types/include/CGAL/Sqrt_extension/Sqrt_extension_type.h
@@ -40,6 +40,7 @@
 #include <CGAL/Sqrt_extension_fwd.h>
 #include <boost/optional.hpp>
 #include <boost/type_traits/is_same.hpp>
+#include <CGAL/NT_converter.h>
 
 #define CGAL_int(T)    typename First_if_different<int,    T>::Type
 
@@ -672,6 +673,48 @@ Sqrt_extension<NT,ROOT,ACDE_TAG,FP_TAG> square (const Sqrt_extension<NT,ROOT,ACD
                                 x.gamma()));
 }
 
+//NT_converter specializations
+template <class NT1,class ROOT1,class NT2,class ROOT2,class ACDE_TAG,class FP_TAG>
+struct NT_converter < Sqrt_extension<NT1,ROOT1,ACDE_TAG,FP_TAG> , Sqrt_extension<NT2,ROOT2,ACDE_TAG,FP_TAG> >
+  : public std::unary_function< NT1, NT2 >
+{
+    Sqrt_extension<NT2,ROOT2,ACDE_TAG,FP_TAG>
+    operator()(const Sqrt_extension<NT1,ROOT1,ACDE_TAG,FP_TAG> &a) const
+    {
+      if(!a.is_extended()) {
+        return Sqrt_extension<NT2,ROOT2,ACDE_TAG,FP_TAG>(NT_converter<NT1,NT2>()(a.a0()));
+      } else {
+        return Sqrt_extension<NT2,ROOT2,ACDE_TAG,FP_TAG>
+            (NT_converter<NT1,NT2>()(a.a0()),
+             NT_converter<NT1,NT2>()(a.a1()),
+             NT_converter<ROOT1,ROOT2>()(a.root()));
+      }
+    }
+};
+
+template <class NT1,class NT2,class ROOT2,class ACDE_TAG,class FP_TAG>
+struct NT_converter < NT1 , Sqrt_extension<NT2,ROOT2,ACDE_TAG,FP_TAG> >
+  : public std::unary_function< NT1, NT2 >
+{
+    Sqrt_extension<NT2,ROOT2,ACDE_TAG,FP_TAG>
+    operator()(const NT1 &a) const
+    {
+        return Sqrt_extension<NT2,ROOT2,ACDE_TAG,FP_TAG>(NT_converter<NT1,NT2>()(a));
+    }
+};
+
+//needed because it's a better match than the specialization <NT1,NT1>
+template <class NT1,class ROOT1,class ACDE_TAG,class FP_TAG>
+struct NT_converter < Sqrt_extension<NT1,ROOT1,ACDE_TAG,FP_TAG>, Sqrt_extension<NT1,ROOT1,ACDE_TAG,FP_TAG> >
+  : public std::unary_function< NT1, NT1 >
+{
+    const Sqrt_extension<NT1,ROOT1,ACDE_TAG,FP_TAG>&
+    operator()(const Sqrt_extension<NT1,ROOT1,ACDE_TAG,FP_TAG> &a) const
+    {
+        return a;
+    }
+};
+
 // UNARY 
 template <class NT,class ROOT,class ACDE_TAG,class FP_TAG> Sqrt_extension<NT,ROOT,ACDE_TAG,FP_TAG>
   operator + (const Sqrt_extension<NT,ROOT,ACDE_TAG,FP_TAG>& p) { return p; }
diff --git a/Number_types/test/Number_types/Sqrt_extension.cpp b/Number_types/test/Number_types/Sqrt_extension.cpp
index e2a5fb1847b..52696fc389c 100644
--- a/Number_types/test/Number_types/Sqrt_extension.cpp
+++ b/Number_types/test/Number_types/Sqrt_extension.cpp
@@ -726,7 +726,20 @@ void sqrt_extension_test(){
     scalar_factor_traits_test<AT,ACDE_TAG>();
     test_algebraic_extension_traits<AT,ACDE_TAG>();
 
-    test_get_arithmetic_kernel<AT,ACDE_TAG>();    
+    test_get_arithmetic_kernel<AT,ACDE_TAG>();
+}
+
+#include <CGAL/internal/Exact_type_selector.h>
+void test_nt_converter()
+{
+  typedef CGAL::internal::Exact_type_selector<int>::Type NT;
+  typedef CGAL::Sqrt_extension<double,double> Source;
+  typedef CGAL::Sqrt_extension<NT,NT> Target;
+  
+  CGAL::NT_converter<Source,Target> converter;
+  
+  Source s;
+  Target t=converter(s);
 }
 
 int main(){ 
@@ -739,7 +752,8 @@ int main(){
   sqrt_extension_test<CGAL::CORE_arithmetic_kernel,CGAL::Tag_false>();
   sqrt_extension_test<CGAL::CORE_arithmetic_kernel,CGAL::Tag_true>();
 #endif // CGAL_HAS_CORE_ARITHMETIC_KERNEL
-    return 0;
+  test_nt_converter();
+  return 0;
 }