Fix Compilation errors when using the MS compiler

src/cpp/flann/algorithms/all_indices.h

@@ -76,12 +76,25 @@ struct same_type<T,T>
 };
 
 
-/**
- * Checks if an index and a distance can be used together
- */
-template<template <typename> class Index, typename Distance, typename ElementType>
-struct valid_combination
+
+struct DummyDistance
 {
+    typedef float ElementType;
+    typedef float ResultType;
+
+    template <typename Iterator1, typename Iterator2>
+    ResultType operator()(Iterator1 a, Iterator2 b, size_t size, ResultType /*worst_dist*/ = -1) const
+    {
+        return ResultType(0);
+    }
+
+    template <typename U, typename V>
+    inline ResultType accum_dist(const U& a, const V& b, int) const
+    {
+        return ResultType(0);
+    }
+};
+
 
 #define HAS_MEMBER(member) \
     template<typename T> \
@@ -93,14 +106,21 @@ struct valid_combination
         enum { value = sizeof (test<T>(0))==sizeof(Yes) }; \
     };
 
-	HAS_MEMBER(needs_kdtree_distance)
-	HAS_MEMBER(needs_vector_space_distance)
-	HAS_MEMBER(is_kdtree_distance)
-	HAS_MEMBER(is_vector_space_distance)
+HAS_MEMBER(needs_kdtree_distance)
+HAS_MEMBER(needs_vector_space_distance)
+HAS_MEMBER(is_kdtree_distance)
+HAS_MEMBER(is_vector_space_distance)
+
 
+/**
+ * Checks if an index and a distance can be used together
+ */
+template<template <typename> class Index, typename Distance, typename ElementType>
+struct valid_combination
+{
     static const bool value = same_type<ElementType,typename Distance::ElementType>::value &&
-    				(!needs_kdtree_distance<Index<Distance> >::value || is_kdtree_distance<Distance>::value) &&
-    				(!needs_vector_space_distance<Index<Distance> >::value || is_kdtree_distance<Distance>::value || is_vector_space_distance<Distance>::value);
+    				(!needs_kdtree_distance<Index<DummyDistance> >::value || is_kdtree_distance<Distance>::value) &&
+    				(!needs_vector_space_distance<Index<DummyDistance> >::value || is_kdtree_distance<Distance>::value || is_vector_space_distance<Distance>::value);
 
 };