From 744dbcbbc71a624caf0b49d8fab909958c4bba02 Mon Sep 17 00:00:00 2001
From: Joel de Guzman <djowel@gmail.com>
Date: Fri, 12 Aug 2011 05:13:03 +0000
Subject: [PATCH] added case for equal_to that returns false immediately if the
 tags are different in the first place

[SVN r73685]
---
 include/boost/fusion/iterator/equal_to.hpp    | 20 ++++++++++++++-----
 .../fusion/iterator/iterator_adapter.hpp      | 19 +++++++++++++-----
 2 files changed, 29 insertions(+), 10 deletions(-)

diff --git a/include/boost/fusion/iterator/equal_to.hpp b/include/boost/fusion/iterator/equal_to.hpp
index a0387417..26bb8d43 100644
--- a/include/boost/fusion/iterator/equal_to.hpp
+++ b/include/boost/fusion/iterator/equal_to.hpp
@@ -1,7 +1,7 @@
 /*=============================================================================
     Copyright (c) 2001-2006 Joel de Guzman
 
-    Distributed under the Boost Software License, Version 1.0. (See accompanying 
+    Distributed under the Boost Software License, Version 1.0. (See accompanying
     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 ==============================================================================*/
 #if !defined(FUSION_EQUAL_TO_05052005_1208)
@@ -37,8 +37,18 @@ namespace boost { namespace fusion
         template <>
         struct equal_to_impl<iterator_facade_tag>
         {
-            template <typename I1, typename I2>
-            struct apply : I1::template equal_to<I1, I2> {};
+            template <typename It1, typename It2, typename Tag1, typename Tag2>
+            struct dispatch : mpl::false_ {};
+
+            template <typename It1, typename It2, typename Tag>
+            struct dispatch<It1, It2, Tag, Tag> // same tag
+              : It1::template equal_to<It1, It2>
+            {};
+
+            template<typename It1, typename It2>
+            struct apply : dispatch<It1, It2,
+                typename It1::fusion_tag, typename It2::fusion_tag>
+            {};
         };
 
         template <>
@@ -63,7 +73,7 @@ namespace boost { namespace fusion
     namespace iterator_operators
     {
         template <typename Iter1, typename Iter2>
-        inline typename 
+        inline typename
         enable_if<
             mpl::and_<is_fusion_iterator<Iter1>, is_fusion_iterator<Iter2> >
             , bool
@@ -74,7 +84,7 @@ namespace boost { namespace fusion
         }
 
         template <typename Iter1, typename Iter2>
-        inline typename 
+        inline typename
         enable_if<
             mpl::and_<is_fusion_iterator<Iter1>, is_fusion_iterator<Iter2> >
             , bool
diff --git a/include/boost/fusion/iterator/iterator_adapter.hpp b/include/boost/fusion/iterator/iterator_adapter.hpp
index 9ba434cb..dea6ddb9 100644
--- a/include/boost/fusion/iterator/iterator_adapter.hpp
+++ b/include/boost/fusion/iterator/iterator_adapter.hpp
@@ -9,6 +9,7 @@
 
 #include <boost/fusion/iterator/detail/advance.hpp>
 #include <boost/fusion/iterator/iterator_facade.hpp>
+#include <boost/type_traits/remove_const.hpp>
 
 namespace boost { namespace fusion
 {
@@ -18,7 +19,9 @@ namespace boost { namespace fusion
             Derived_
           , typename Iterator_::category>
     {
-        typedef Iterator_ iterator_base_type;
+        typedef typename
+            remove_const<Iterator_>::type
+        iterator_base_type;
         iterator_base_type iterator_base;
 
         iterator_adapter(iterator_base_type const& iterator_base)
@@ -36,12 +39,18 @@ namespace boost { namespace fusion
         // default implementation
         template <typename Iterator, typename N>
         struct advance
-            : Derived_::template make<
+        {
+            typedef typename Derived_::template make<
                 typename result_of::advance<
                     typename Iterator::iterator_base_type, N
-                >::type
-            >
-        {
+                >::type>::type
+            type;
+
+            static type
+            call(Iterator const& it)
+            {
+                return type(fusion::advance<N>(it.iterator_base));
+            }
         };
 
         // default implementation