[Boost-commit] svn:boost r43415 - sandbox/switch/libs/switch/alternate/switch

From: steven_at_[hidden]
Date: 2008-02-25 17:48:07

Author: steven_watanabe
Date: 2008-02-25 17:48:07 EST (Mon, 25 Feb 2008)
New Revision: 43415
URL: http://svn.boost.org/trac/boost/changeset/43415

Log:
Optimized be replacing fold with a custom loop
Text files modified: 
   sandbox/switch/libs/switch/alternate/switch/case.hpp |    18 ++++++++++++++----                      
   1 files changed, 14 insertions(+), 4 deletions(-)

Modified: sandbox/switch/libs/switch/alternate/switch/case.hpp
==============================================================================
--- sandbox/switch/libs/switch/alternate/switch/case.hpp	(original)
+++ sandbox/switch/libs/switch/alternate/switch/case.hpp	2008-02-25 17:48:07 EST (Mon, 25 Feb 2008)
@@ -12,7 +12,6 @@
 
 #include <boost/utility/enable_if.hpp>
 #include <boost/mpl/int.hpp>
-#include <boost/mpl/fold.hpp>
 #include <boost/mpl/joint_view.hpp>
 #include <boost/mpl/single_view.hpp>
 #include <boost/mpl/range_c.hpp>
@@ -33,14 +32,25 @@
     typedef set type;
 };
 
-template<class S>
+template<int N>
 struct make_set {
-    typedef typename mpl::fold<S, empty_set, set<mpl::_, mpl::_> >::type type;
+    template<class Iter>
+    struct apply {
+        typedef set<typename make_set<N - 1>::template apply<typename boost::mpl::next<Iter>::type>::type, typename boost::mpl::deref<Iter>::type> type;
+    };
+};
+
+template<>
+struct make_set<0> {
+    template<class Iter>
+    struct apply {
+        typedef empty_set type;
+    };
 };
 
 template<class S, class N>
 struct contains_impl {
-    typedef typename switch_detail::make_set<S>::type as_set;
+    typedef typename make_set<boost::mpl::size<S>::value>::template apply<typename boost::mpl::begin<S>::type>::type as_set;
     static const bool value = (sizeof(as_set::lookup(N())) != 1);
 };