BAN: implement quick sort and test for it

BAN/include/BAN/Sort.h

@@ -15,6 +15,43 @@ namespace BAN
 					swap(*lhs, *rhs);
 	}
 
+	namespace detail
+	{
 
+		template<typename It, typename Comp>
+		It sort_quick_partition(It begin, It end, Comp comp)
+		{
+			It pivot = end; --pivot;
+
+			It it1 = begin;
+			for (It it2 = begin; it2 != pivot; ++it2)
+			{
+				if (comp(*it2, *pivot))
+				{
+					swap(*it1, *it2);
+					++it1;
+				}
+			}
+
+			swap(*it1, *pivot);
+
+			return it1;
+		}
+
+	}
+
+	template<typename It, typename Comp = less<typename It::value_type>>
+	void sort_quick(It begin, It end, Comp comp = {})
+	{
+		{
+			It it = begin;
+			if (it == end || ++it == end)
+				return;
+		}
+
+		It mid = detail::sort_quick_partition(begin, end, comp);
+		sort_quick(begin, mid, comp);
+		sort_quick(++mid, end, comp);
+	}
 
 }