From 0d9709e1bf2b6e4842307575422563c43955373a Mon Sep 17 00:00:00 2001
From: Daniel Frey <d.frey@gmx.de>
Date: Fri, 22 Jan 2010 20:50:15 +0000
Subject: [PATCH] functional (_Index_tuple, [...]): Simplify and speed-up.

2010-01-22  Daniel Frey  <d.frey@gmx.de>

	* include/std/functional (_Index_tuple, _Build_index_tuple):
	Simplify and speed-up.

From-SVN: r156178
---
 libstdc++-v3/ChangeLog              |  5 +++++
 libstdc++-v3/include/std/functional | 24 ++++++++++++------------
 2 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index bfdf16a..28db3d7 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,3 +1,8 @@
+2010-01-22  Daniel Frey  <d.frey@gmx.de>
+
+	* include/std/functional (_Index_tuple, _Build_index_tuple):
+	Simplify and speed-up.
+
 2010-01-22  Joern Rennecke  <amylaar@spamcop.net>
 
 	PR libstdc++/36101, PR libstdc++/42813
diff --git a/libstdc++-v3/include/std/functional b/libstdc++-v3/include/std/functional
index f28490a..68b7842 100644
--- a/libstdc++-v3/include/std/functional
+++ b/libstdc++-v3/include/std/functional
@@ -847,22 +847,22 @@ namespace std
    * in a tuple. 
    */
   template<int... _Indexes>
-    struct _Index_tuple { };
+    struct _Index_tuple
+    {
+      typedef _Index_tuple<_Indexes..., sizeof...(_Indexes)> __next;
+    };
 
   /// Builds an _Index_tuple<0, 1, 2, ..., _Num-1>.
-  template<std::size_t _Num, typename _Tuple = _Index_tuple<> >
-    struct _Build_index_tuple;
- 
-  template<std::size_t _Num, int... _Indexes> 
-    struct _Build_index_tuple<_Num, _Index_tuple<_Indexes...> >
-    : _Build_index_tuple<_Num - 1, 
-                         _Index_tuple<_Indexes..., sizeof...(_Indexes)> >
-    { };
+  template<std::size_t _Num>
+    struct _Build_index_tuple
+    {
+      typedef typename _Build_index_tuple<_Num-1>::__type::__next __type;
+    };
 
-  template<int... _Indexes>
-    struct _Build_index_tuple<0, _Index_tuple<_Indexes...> >
+  template<>
+    struct _Build_index_tuple<0>
     {
-      typedef _Index_tuple<_Indexes...> __type;
+      typedef _Index_tuple<> __type;
     };
 
   /** 
-- 
2.7.4